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Bar Shira E, Friedman A. Innate immune functions of avian intestinal epithelial cells: Response to bacterial stimuli and localization of responding cells in the developing avian digestive tract. PLoS One 2018; 13:e0200393. [PMID: 29979771 PMCID: PMC6034880 DOI: 10.1371/journal.pone.0200393] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 06/25/2018] [Indexed: 12/16/2022] Open
Abstract
Intestinal epithelial cells are multi-tasked cells that participate in digestion and absorption as well as in protection of the digestive tract. While information on the physiology and immune functions of intestinal epithelial cells in mammals is abundant, little is known of their immune function in birds and other species. Our main objectives were to study the development of anti-bacterial innate immune functions in the rapidly developing gut of the pre- and post-hatch chick and to determine the functional diversity of epithelial cells. After establishing primary intestinal epithelial cell cultures, we demonstrated their capacity to uptake and process bacteria. The response to bacterial products, LPS and LTA, induced expression of pro-inflammatory cytokine genes (IL-6, IL-18) as well as the expression of the acute phase proteins avidin, lysozyme and the secretory component derived from the polymeric immunoglobulin receptor. These proteins were then localized in gut sections, and the goblet cell was shown to store avidin, lysozyme as well as secretory component. Lysozyme staining was also located in a novel rod-shaped intestinal cell, situated at different loci along the villus, thus deviating from the classical Paneth cell in the mammal, that is restricted to crypts. Thus, in the chicken, the intestinal epithelium, and particularly goblet cells, are committed to innate immune protection. The unique role of the goblet cell in chicken intestinal immunity, as well as the unique distribution of lysozyme-positive cells highlight alternative solutions of gut protection in the bird.
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Affiliation(s)
- Enav Bar Shira
- Department of Animal Sciences, Robert H. Smith Faculty of Agriculture Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Aharon Friedman
- Department of Animal Sciences, Robert H. Smith Faculty of Agriculture Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
- * E-mail:
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Petruzzelli M, Piccinin E, Pinto C, Peres C, Bellafante E, Moschetta A. Biliary Phospholipids Sustain Enterocyte Proliferation and Intestinal Tumor Progression via Nuclear Receptor Lrh1 in mice. Sci Rep 2016; 6:39278. [PMID: 27995969 PMCID: PMC5171812 DOI: 10.1038/srep39278] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/21/2016] [Indexed: 01/02/2023] Open
Abstract
The proliferative-crypt compartment of the intestinal epithelium is enriched in phospholipids and accumulation of phospholipids has been described in colorectal tumors. Here we hypothesize that biliary phospholipid flow could directly contribute to the proliferative power of normal and dysplastic enterocytes. We used Abcb4-/- mice which lack biliary phospholipid secretion. We first show that Abcb4-/- mice are protected against intestinal tumorigenesis. At the molecular level, the transcriptional activity of the nuclear receptor Liver Receptor Homolog-1 (Lrh1) is reduced in Abcb4-/- mice and its re-activation re-establishes a tumor burden comparable to control mice. Feeding Abcb4-/- mice a diet supplemented with phospholipids completely overcomes the intestinal tumor protective phenotype, thus corroborating the hypothesis that the absence of biliary phospholipids and not lack of Abcb4 gene per se is responsible for the protection. In turn, phospholipids cannot re-establish intestinal tumorigenesis in Abcb4-/- mice crossed with mice with intestinal specific ablation of Lrh1, a nuclear hormone receptor that is activates by phospholipids. Our data identify the key role of biliary phospholipids in sustaining intestinal mucosa proliferation and tumor progression through the activation of nuclear receptor Lrh1.
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Affiliation(s)
- Michele Petruzzelli
- Department of Interdisciplinary Medicine, “Aldo Moro” University of Bari, 70124 Bari, Italy
- Fondazione Mario Negri Sud, Santa Maria Imbaro, 66030 Chieti, Italy
| | - Elena Piccinin
- Department of Interdisciplinary Medicine, “Aldo Moro” University of Bari, 70124 Bari, Italy
- National Cancer Research Center, IRCCS Istituto Oncologico “Giovanni Paolo II”, 70124 Bari, Italy
- INBB, National Institute for Biostuctures and Biosystems, 00136 Rome, Italy
| | - Claudio Pinto
- Fondazione Mario Negri Sud, Santa Maria Imbaro, 66030 Chieti, Italy
| | - Claudia Peres
- Department of Interdisciplinary Medicine, “Aldo Moro” University of Bari, 70124 Bari, Italy
- INBB, National Institute for Biostuctures and Biosystems, 00136 Rome, Italy
| | - Elena Bellafante
- Fondazione Mario Negri Sud, Santa Maria Imbaro, 66030 Chieti, Italy
| | - Antonio Moschetta
- Department of Interdisciplinary Medicine, “Aldo Moro” University of Bari, 70124 Bari, Italy
- National Cancer Research Center, IRCCS Istituto Oncologico “Giovanni Paolo II”, 70124 Bari, Italy
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Bar-Shira E, Cohen I, Elad O, Friedman A. Role of goblet cells and mucin layer in protecting maternal IgA in precocious birds. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 44:186-194. [PMID: 24370536 DOI: 10.1016/j.dci.2013.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 12/14/2013] [Accepted: 12/15/2013] [Indexed: 06/03/2023]
Abstract
Immune protection of the gut in early life depends on provision of maternal antibodies, particularly that of IgA. In precocial birds (in this study Gallus gallus domesticus) the egg provides the only source of maternal antibodies, IgA inclusive. The gut-life of IgA in hatchlings is expected to be brief due to antigen binding and intestinal washout, and maternal IgA is likely to be depleted prior to immune independence at 7-10 days of age in the domestic fowl. We followed the track of maternal IgA in mucosal surfaces of the fowl and describe for the first time a mechanism that might provide the means to extend the active period of maternal IgA in the gut. Maternal IgA was located in the gut, lung, and cloacal bursa in embryos and hatchlings prior to the appearance of endogenic IgA positive plasma cells (D3 in the bursa or D7 in the gut and lung); the source of IgA was most probably the yolk, as the plasma was devoid of IgA till D7 post-hatch. The levels of maternal IgA decreased with time, but were still easily determined at the onset of endogenous IgA production following maturation of the adaptive immune system. Persistence of maternal IgA in the gut was enabled by goblet cell up-take by a yet un-described mechanism, and its consequent release in a mucin-like layer on enterocyte apical surfaces.
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Affiliation(s)
- Enav Bar-Shira
- Animal Sciences, R.H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel
| | - Inbal Cohen
- Animal Sciences, R.H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel
| | - Ori Elad
- Animal Sciences, R.H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel
| | - Aharon Friedman
- Animal Sciences, R.H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel.
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The Importance of Villous Physiology and Morphology in Mechanistic Physiologically-Based Pharmacokinetic Models. Pharm Res 2013; 31:305-21. [DOI: 10.1007/s11095-013-1161-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/28/2013] [Indexed: 01/11/2023]
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Yang C, Albin DM, Wang Z, Stoll B, Lackeyram D, Swanson KC, Yin Y, Tappenden KA, Mine Y, Yada RY, Burrin DG, Fan MZ, Arrese M, Riquelme A. Apical Na+-D-glucose cotransporter 1 (SGLT1) activity and protein abundance are expressed along the jejunal crypt-villus axis in the neonatal pig. Am J Physiol Gastrointest Liver Physiol 2011; 300:G60-70. [PMID: 21030609 PMCID: PMC3025512 DOI: 10.1152/ajpgi.00208.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gut apical Na(+)-glucose cotransporter 1 (SGLT1) activity is high at the birth and during suckling, thus contributing substantially to neonatal glucose homeostasis. We hypothesize that neonates possess high SGLT1 maximal activity by expressing apical SGLT1 protein along the intestinal crypt-villus axis via unique control mechanisms. Kinetics of SGLT1 activity in apical membrane vesicles, prepared from epithelial cells sequentially isolated along the jejunal crypt-villus axis from neonatal piglets by the distended intestinal sac method, were measured. High levels of maximal SGLT1 uptake activity were shown to exist along the jejunal crypt-villus axis in the piglets. Real-time RT-PCR analyses showed that SGLT1 mRNA abundance was lower (P < 0.05) by 30-35% in crypt cells than in villus cells. There were no significant differences in SGLT1 protein abundances on the jejunal apical membrane among upper villus, middle villus, and crypt cells, consistent with the immunohistochemical staining pattern. Higher abundances (P < 0.05) of total eukaryotic initiation factor 4E (eIF4E) protein and eIE4E-binding protein 1 γ-isoform in contrast to a lower (P < 0.05) abundance of phosphorylated (Pi) eukaryotic elongation factor 2 (eEF2) protein and the eEF2-Pi to total eEF2 abundance ratio suggest higher global protein translational efficiency in the crypt cells than in the upper villus cells. In conclusion, neonates have high intestinal apical SGLT1 uptake activity by abundantly expressing SGLT1 protein in the epithelia and on the apical membrane along the entire crypt-villus axis in association with enhanced protein translational control mechanisms in the crypt cells.
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Affiliation(s)
- Chengbo Yang
- 1Center for Nutrition Modeling, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada;
| | - David M. Albin
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, Illinois;
| | - Zirong Wang
- 3College of Animal Science, Xinjiang Agricultural University, Urumqi, Xinjiang, China;
| | - Barbara Stoll
- 4Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas;
| | - Dale Lackeyram
- 1Center for Nutrition Modeling, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada;
| | - Kendall C. Swanson
- 1Center for Nutrition Modeling, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada;
| | - Yulong Yin
- 5Institute of Subtropical Agriculture, the Chinese Academy of Sciences, Changsha, Hunan, China; and
| | - Kelly A. Tappenden
- 2Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, Illinois;
| | - Yoshinori Mine
- 6Department of Food Science, University of Guelph, Guelph, Ontario, Canada
| | - Rickey Y. Yada
- 6Department of Food Science, University of Guelph, Guelph, Ontario, Canada
| | - Douglas G. Burrin
- 4Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas;
| | - Ming Z. Fan
- 1Center for Nutrition Modeling, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada;
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Prakash UNS, Srinivasan K. Beneficial influence of dietary spices on the ultrastructure and fluidity of the intestinal brush border in rats. Br J Nutr 2010; 104:31-9. [PMID: 20178671 DOI: 10.1017/s0007114510000334] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The beneficial influence of three common spices was examined in experimental rats on: (i) the membrane fluidity of intestinal brush-border membranes (BBM), (ii) the activity of intestinal membrane-bound enzymes, and (iii) ultrastructural alterations in the intestinal epithelium. Groups of male Wistar rats were maintained on dietary black pepper (0.5 %), red pepper (3.0 %), ginger (0.05 %) and spice bioactive compounds piperine (0.02 %) and capsaicin (0.01 %) for 8 weeks. A membrane fluidity study using an apolar fluorescent probe showed increased BBM fluidity in all the spice-fed animals. This was corroborated by a decreased cholesterol:phospholipid ratio in the jejunal and ileal regions of the intestine. These dietary spices stimulated the activities of BBM enzymes (glycyl-glycine dipeptidase, leucine amino peptidase and gamma-glutamyl transpeptidase) in the jejunal mucosa, suggesting a modulation in membrane dynamics due to the apolar spice bioactive compounds interacting with surrounding lipids and hydrophobic portions in the protein vicinity, which may decrease the tendency of membrane lipids to act as steric constraints to enzyme proteins and thus modify enzyme conformation. Scanning electronic microscopy of the intestinal villi in these spice treatments revealed alterations in the ultrastructure, especially an increase in microvilli length and perimeter which would mean a beneficial increase in the absorptive surface of the small intestine, providing for an increased bioavailability of micronutrients. Thus, dietary spices (black pepper, red pepper and ginger) were evidenced to induce alterations in BBM fluidity and passive permeability property, associated with the induction of an increased microvilli length and perimeter, resulting in an increased absorptive surface of the small intestine.
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Affiliation(s)
- Usha N S Prakash
- Department of Biochemistry and Nutrition, Central Food Technological Research Institute, CSIR, Mysore 570 020, India
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Drozdowski LA, Iordache C, Clandinin MT, Todd Z, Gonnet M, Wild G, Uwiera RR, Thomson AB. Maternal dexamethasone and GLP-2 have early effects on intestinal sugar transport in their suckling rat offspring. J Nutr Biochem 2009; 20:771-82. [DOI: 10.1016/j.jnutbio.2008.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2007] [Revised: 06/24/2008] [Accepted: 07/09/2008] [Indexed: 01/30/2023]
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Drozdowski LA, Clandinin MT, Thomson ABR. Morphological, kinetic, membrane biochemical and genetic aspects of intestinal enteroplasticity. World J Gastroenterol 2009; 15:774-87. [PMID: 19230039 PMCID: PMC2653378 DOI: 10.3748/wjg.15.774] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The process of intestinal adaptation (“enteroplasticity”) is complex and multifaceted. Although a number of trophic nutrients and non-nutritive factors have been identified in animal studies, successful, reproducible clinical trials in humans are awaited. Understanding mechanisms underlying this adaptive process may direct research toward strategies that maximize intestinal function and impart a true clinical benefit to patients with short bowel syndrome, or to persons in whom nutrient absorption needs to be maximized. In this review, we consider the morphological, kinetic and membrane biochemical aspects of enteroplasticity, focus on the importance of nutritional factors, provide an overview of the many hormones that may alter the adaptive process, and consider some of the possible molecular profiles. While most of the data is derived from rodent studies, wherever possible, the results of human studies of intestinal enteroplasticity are provided.
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9
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Murray LJ, Tully O, Rudolph DS, Whitby M, Valenzano MC, Mercogliano G, Thornton JJ, Mullin JM. Absence of Na +/sugar cotransport activity in Barrett’s metaplasia. World J Gastroenterol 2008; 14:1365-9. [PMID: 18322949 PMCID: PMC2693683 DOI: 10.3748/wjg.14.1365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate the presence of Na+-dependent, active, sugar transport in Barrett's epithelia as an intestinal biomarker, based on the well-documented, morphological intestinal phenotype of Barrett's esophagus (BE).
METHODS: We examined uptake of the nonmeta-bolizable glucose analogue, alpha-methyl-D-glucoside (AMG), a substrate for the entire sodium glucose cotransporter (SGLT) family of transport proteins. During upper endoscopy, patients with BE or with uncomplicated gastroesophageal reflux disease (GERD) allowed for duodenal, gastric fundic, and esophageal mucosal biopsies to be taken. Biopsies were incubated in bicarbonate-buffered saline (KRB) containing 0.1 mmol/L 14C-AMG for 60 min at 20°C. Characterized by abundant SGLT, duodenum served as a positive control while gastric fundus and normal esophagus, known to lack SGLT, served as negative controls.
RESULTS: Duodenal biopsies accumulated 249.84 ± 35.49 (SEM) picomoles AMG/&mgr;g DNA (n = 12), gastric fundus biopsies 36.20 ± 6.62 (n = 12), normal esophagus 12.10 ± 0.59 (n = 3) and Barrett’s metaplasia 29.79 ± 5.77 (n = 8). There was a statistical difference (P < 0.01) between biopsies from duodenum and each other biopsy site but there was no statistically significant difference between normal esophagus and BE biopsies. 0.5 mmol/L phlorizin (PZ) inhibited AMG uptake into duodenal mucosa by over 89%, but had no significant effect on AMG uptake into gastric fundus, normal esophagus, or Barrett’s tissue. In the absence of Na+ (all Na+ salts replaced by Li+ salts), AMG uptake in duodenum was decreased by over 90%, while uptake into gastric, esophageal or Barrett’s tissue was statistically unaffected.
CONCLUSION: Despite the intestinal enterocyte phenotype of BE, Na+-dependent, sugar transport activity is not present in these cells.
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Lodemann U, Lorenz BM, Weyrauch KD, Martens H. Effects ofBacillus cereus var.toyoi as probiotic feed supplement on intestinal transport and barrier function in piglets. Arch Anim Nutr 2008; 62:87-106. [DOI: 10.1080/17450390801912068] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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11
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Lorrot M, Benhamadouche-Casari H, Vasseur M. Mechanisms of net chloride secretion during rotavirus diarrhea in young rabbits: do intestinal villi secrete chloride? Cell Physiol Biochem 2006; 18:103-12. [PMID: 16914895 DOI: 10.1159/000095174] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Rotaviral diarrheal illness is one of the most common infectious diseases in children worldwide, but our understanding of its pathophysiology is limited. This study examines whether the enhanced net chloride secretion during rotavirus infection in young rabbits may occur as a result of hypersecretion in crypt cells that would exceed the substantial Cl(-) reabsorption observed in villi. By using a rapid filtration technique, we evaluated transport of (36)Cl and D-(14)C glucose across brush border membrane (BBM) vesicles purified from villus tip and crypt cells isolated in parallel from the entire small intestine. Rotavirus infection impaired SGLT1-mediated Na(+)-D-glucose symport activity in both villus and crypt cell BBM, hence contributing to the massive water loss along the cryptvillus axis. In the same BBM preparations, rotavirus failed to stimulate the Cl(-) transport activities (Cl(-)/H(+) symport, Cl(-)/anion exchange and voltage-activated Cl(-) conductance) at the crypt level, but not at the villus level, questioning, therefore, the origin of net chloride secretion. We propose that the chloride carrier might function in both normal (absorption) and reversed (secretion) modes in villi, depending on the direction of the chloride electrochemical gradient resulting from rotavirus infection, agreeing with our results that rotavirus accelerated both Cl(-) influx and Cl(-) efflux rates across villi BBM.
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Affiliation(s)
- Mathie Lorrot
- INSERM UMR 756, Université Paris XI, Faculté de Pharmacie, Châtenay-Malabry, France
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Abstract
Intestinal failure is a condition characterized by malnutrition and/or dehydration as a result of the inadequate digestion and absorption of nutrients. The most common cause of intestinal failure is short bowel syndrome, which occurs when the functional gut mass is reduced below the level necessary for adequate nutrient and water absorption. This condition may be congenital, or may be acquired as a result of a massive resection of the small bowel. Following resection, the intestine is capable of adaptation in response to enteral nutrients as well as other trophic stimuli. Identifying factors that may enhance the process of intestinal adaptation is an exciting area of research with important potential clinical applications.
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13
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Tomimatsu T, Horie T. Enhanced glucose absorption in the rat small intestine following repeated doses of 5-fluorouracil. Chem Biol Interact 2005; 155:129-39. [PMID: 15996645 DOI: 10.1016/j.cbi.2005.04.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 04/12/2005] [Indexed: 11/17/2022]
Abstract
Many studies demonstrated that 5-fluorouracil (5-FU) treatment of rodents caused the damage of small intestine, resulting in the malabsorption, while we recently found that repeated administration of 5-FU to rats increased Na(+)-dependent glucose absorption in the small intestine. This study investigated the cause of enhanced glucose absorption. 3-O-methyl-d-glucose (3-OMG) absorption was examined using the everted intestine technique. d-Glucose uptake, phlorizin binding, Western blot analysis and membrane fluidity were examined using small intestinal brush-border membrane vesicles (BBMV). Repeated oral administration of 5-FU to rats increased Na(+)-dependent 3-OMG absorption in the small intestine, while alkaline phosphatase activity in the small intestine decreased. Na(+)/K(+)-ATPase activity of 5-FU-treated rats was about three-fold higher than that of control rats. Although the amount of Na(+)-dependent glucose co-transporter (SGLT1) in 5-FU-treated rats decreased, the overshoot magnitude of d-glucose uptake in BBMV was not altered. Maximum binding of phlorizin in 5-FU-treated rats was 1.5-fold larger than that of control rats, but not altered the maximal rate of d-glucose absorption, Michaelis constant of d-glucose and dissociation constant of phlorizin. The membrane fluidity of 5-FU-treated rats increased. The enhanced d-glucose absorption in 5-FU-treated rats seems to occur secondarily due to the activation of Na(+)/K(+)-ATPase activity in basolateral membranes (BLM). Because the amounts of SGLT1 in 5-FU-treated rats decreased, the increase of turnover rate of SGLT1 and/or an expression of unknown Na(+)-dependent glucose co-transporter with high affinity for d-glucose and phlorizin sensitivity would contribute to the enhancement of d-glucose transport in 5-FU-treated rats.
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Affiliation(s)
- Takashi Tomimatsu
- Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan
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Drozdowski LA, Woudstra TD, Wild GE, Clandinin MT, Thomson ABR. Age-associated changes in intestinal fructose uptake are not explained by alterations in the abundance of GLUT5 or GLUT2. J Nutr Biochem 2005; 15:630-7. [PMID: 15542355 DOI: 10.1016/j.jnutbio.2004.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A reduction in nutrient absorption may contribute to malnourishment in the elderly. The objectives of this study were to determine the effects of aging on the absorption of fructose in rats, as well as the mechanisms of these adaptive changes. Male Fischer 344 rats aged 1, 9, and 24 months were fed standard Purina chow for 2 weeks (PMI #5001, PMI Nutritionals, Brentwood, MO). The uptake of (14)C-labeled D-fructose was determined in vitro using the intestinal sheet method. Intestinal samples were taken for RNA isolation and for brush border membrane (BBM) and basolateral membrane (BLM) preparation. Northern blotting, Western blotting, and immunohistochemistry were used to determine the effects of age and diet on GLUT5 and GLUT2. When expressed on the basis of intestinal or mucosal weights, aging was associated with a decline in jejunal and ileal fructose uptake, whereas jejunal fructose uptake was increased when expressed on the basis of serosal or mucosal surface area. The alterations in fructose uptake were not paralleled by changes in GLUT5 or GLUT2 abundance. These results indicate that 1) the effect of age on fructose uptake depends on the method used to express results, and 2) the age-associated changes in uptake are not explained by alterations in GLUT5 and GLUT2.
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Affiliation(s)
- Laurie A Drozdowski
- Nutrition and Metabolism Group, Division of Gastroenterology, Department of Medicine, 5146 Dentistry Pharmacy Building, University of Alberta, Edmonton, AB T6G 2N8, Canada
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15
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Drozdowski L, Woudstra T, Wild G, Clandinin MT, Thomson ABR. Dietary lipids modify the age-associated changes in intestinal uptake of fructose in rats. Am J Physiol Gastrointest Liver Physiol 2005; 288:G125-34. [PMID: 15513953 DOI: 10.1152/ajpgi.00311.2003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Because reduced nutrient absorption may contribute to malnourishment in the elderly, age and diet modulate fructose uptake in mice, and alterations in fructose uptake may be paralleled by changes in the abundance of fructose transporters, the objectives of this study were to determine 1) the effects of aging on fructose absorption in rats, 2) the effect of feeding diets enriched with saturated fatty acids (SFA) vs. polyunsaturated fatty acids (PUFA), and 3) the mechanisms of these age-and diet-associated changes. Male Fischer 344 rats aged 1, 9, and 24 mo received isocaloric diets enriched with SFA or PUFA. The uptake of (14)C-labeled D-fructose was determined in vitro using the intestinal sheet method. Northern and Western blot analyses and immunohistochemistry were used to determine the abundance of sodium-independent glucose and fructose transporters (GLUT)2 and GLUT5. When expressed on the basis of mucosal surface area, jejunal fructose uptake was increased in 9 and 24 mo compared with 1-mo-old animals fed SFA. PUFA-fed animals demonstrated increased fructose uptake at 24 mo compared with younger animals. Ileal fructose uptake was increased with SFA vs. PUFA in 9-mo-old rats but was reduced with SFA in 1- and 24-mo-old rats. Variations in GLUT2 and GLUT5 abundance did not parallel changes in uptake. These results indicate that 1) age increases fructose uptake when expressed on the basis of mucosal surface area, 2) age influences the adaptive response to dietary lipid modifications, and 3) alterations in fructose uptake are not explained by variations in GLUT2 or GLUT5.
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Affiliation(s)
- L Drozdowski
- Nutrition and Metabolism Group, Division of Gastroenterology, University of Alberta, Edmonton, AB T6G 2C8, Canada
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Drozdowski L, Woudstra T, Wild G, Clandindin MT, Thomson ABR. The age-associated decline in the intestinal uptake of glucose is not accompanied by changes in the mRNA or protein abundance of SGLT1. Mech Ageing Dev 2004; 124:1035-45. [PMID: 14659592 DOI: 10.1016/j.mad.2003.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Studies performed using human and animal models offer conflicting results regarding the effect of age on nutrient absorption. The objectives of this study were to determine (1) the effects of aging on the in vitro uptake of glucose in rats; and (2) the molecular mechanisms of these age-associated changes. Male Fischer 344 rats aged 1, 9 and 24 months were fed a standard laboratory diet (PMI # 5001). The uptake of 14C-labelled D-glucose was determined in vitro using the intestinal sheet method. Northern blotting, Western blotting and immunohistochemistry were used to determine the effects of age on the BBM sodium-dependent glucose transporter, SGLT1, and the BLM Na+K(+)-ATPase. When expressed on the basis of intestinal weight, mucosal weight or surface area, there was a reduction in glucose uptake in the 24-month-old animals. SGLT1, GLUT2 and Na+K(+)-ATPase mRNA and protein abundance did not parallel the changes seen in glucose uptake. These results indicate that (1) age reduces in vitro intestinal glucose uptake in the rat; and (2) this age-associated decline in glucose uptake was not explained by alterations in SGLT1, GLUT2 or Na+K(+)-ATPase.
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Affiliation(s)
- L Drozdowski
- Nutrition and Metabolism Group, Department of Medicine, Division of Gastroenterology, 5150 Dentistry Pharmacy Building, University of Alberta, Edmonton,Alta., Canada T6G 2N8
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Kimura Y, Buddington KK, Buddington RK. The influence of estradiol and diet on small intestinal glucose transport in ovariectomized rats. Exp Biol Med (Maywood) 2004; 229:227-34. [PMID: 14988514 DOI: 10.1177/153537020422900302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Although gender differences exist for intestinal absorption of nutrients and drugs, the possible role estradiol may play in modulating nutrient transport has not been established. Therefore, small intestine glucose transport was measured 1 week after administering estradiol to ovariectomized rats fed diets high in carbohydrate (C) or protein (P). Rats treated with estradiol ate 21% less (P<0.05) and lost body mass (7%; P<0.05) but did not have smaller intestines. Administration of estradiol increased rates of glucose transport, but only when the rats were fed the C diet. These findings indicate that estradiol causes a disconnect between food intake and the dimensions and nutrient transport capacities of the small intestine. Furthermore, the responses to estradiol are influenced by diet composition, are not of the same magnitude for rats and dogs, and can be predicted to affect systemic availability of nutrients and drugs.
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Affiliation(s)
- Yasuhiro Kimura
- Department of Biological Sciences, Mississippi State University, Mississippi State, Mississippi 39762, USA
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18
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Thiesen A, Drozdowski L, Iordache C, Neo CC, Woudstra TD, Xenodemetropoulos T, Keelan M, Clandinin MT, Thomson ABR, Wild G. Adaptation following intestinal resection: mechanisms and signals. Best Pract Res Clin Gastroenterol 2003; 17:981-95. [PMID: 14642861 DOI: 10.1016/s1521-6918(03)00097-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The intestine has an inherent ability to adapt morphologically and functionally in response to internal and external environmental changes. The functional adaptations encompass modifications of the brush border membrane fluidity and permeability, as well as up- or down-regulation of carrier-mediated transport. Intestinal adaptation improves the nutritional status following the loss of a major portion of the small intestine, following chronic ingestion of ethanol, following sublethal doses of abdominal irradiation, in diabetes, in pregnancy and lactation, with ageing, and with fasting and malnutrition. Following intestinal resection, morphological and functional changes occur depending upon the extent of the intestine removed, the site studied, and the lipid content of the diet. Therefore, intestinal adaptation has important implications in the survival potential and welfare of the host. An understanding of the mechanisms of, and signals for, intestinal adaptation in the experimental setting forms the basis for the use of management strategies in humans with the short-bowel syndrome.
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Affiliation(s)
- A Thiesen
- Nutrition and Metabolism Research Group, Division of Gastroenterology, Department of Medicine, University of Alberta, 519 Newton Research Building, 205 College Plaza, 8215-112 Street, Edmonton, Alta, Canada T6G 2C2.
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19
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Abstract
OBJECTIVE To measure nutrient absorption by the intestine during postnatal development of dogs. ANIMAL 110 Beagles ranging from neonatal to adult dogs. PROCEDURE Rates of absorption for sugars (glucose, galactose, and fructose), amino acids (aspartate, leucine, lysine, methionine, and proline), a dipeptide (glycyl-sarcosine), and linoleic acid by the proximal, mid, and distal regions of the small intestine were measured as functions of age and concentration (kinetics) by use of intact tissues and brush-border membrane vesicles. Absorption of octanoic acid by the proximal portion of the colon was measured in intact tissues. RESULTS Rates of carrier-mediated transport by intact tissues decreased from birth to adulthood for aldohexoses and most amino acids but not for fructose and aspartate. Kinetics and characteristics of absorption suggest that there were changes in the densities, types, and proportions of various carriers for sugars and amino acids. Saturable absorption of linoleic acid in the small intestine and octanoic acid in the proximal portion of the colon increased after weaning. CONCLUSIONS AND CLINICAL RELEVANCE Rates of absorption decreased between birth and adulthood for most nutrients. However, because of intestinal growth, absorption capacities of the entire small intestine remained constant for leucine and proline and increased for glucose, galactose, fructose, aspartate, and proline but were less than predicted from the increase in body weight. Although postnatal ontogeny of nutrient absorption was consistent with changes in the composition of the natural and commercial diets of growing dogs, rates of amino acid and peptide absorption were lower than expected.
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Affiliation(s)
- Randal K Buddington
- Department of Biological Sciences, College of Arts and Science, Mississippi State University, Mississippi State, MS 39762, USA
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20
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Chotinsky D, Toncheva E, Profirov Y. Development of disaccharidase activity in the small intestine of broiler chickens. Br Poult Sci 2001; 42:389-93. [PMID: 11469561 DOI: 10.1080/00071660120055386] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
1. The changes in disaccharidase activity in the small intestine of broiler chickens were investigated in isolated enterocytes on d 18 of embryonic development and d 1, 7, 21, 35 and 56 after hatching. 2. The specific activities of maltase, lactase and trehalase were greatest on d 18 of embryonic development. After hatching, maltase specific activity gradually decreased until d 18. 3. After d 7 postnatally only traces of lactase and trehalase activity were found in the enterocytes. 4. Significant sucrase activity was found on d 18 of embryonic development and the activity of this enzyme increased 2-fold after hatch and remained generally constant up to d 35, after which the enzyme specific activity declined.
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Affiliation(s)
- D Chotinsky
- Department of Nutrition, Physiology and Biochemistry, Poultry Research Institute, Kostinbrod, Bulgaria
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21
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Jourd'heuil D, Meddings JB. Oxidative and drug-induced alterations in brush border membrane hemileaflet fluidity, functional consequences for glucose transport. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1510:342-53. [PMID: 11342171 DOI: 10.1016/s0005-2736(00)00367-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Oxidation of biological membranes has been suggested as a major pathological process in a variety of disease states including intestinal ischemia and inflammatory bowel disease. Previous studies on the small intestinal brush border membrane have shown that part of the decrease in the activity of the Na(+)-dependent glucose transporter (SGLT1) observed after oxidation could be secondary to the derangement in membrane fluidity that accompanied oxidative damage. The present study examined the relationship between oxidative-induced hemileaflet fluidity alterations and the resultant change in Na(+)-dependent glucose transport activity. To address this issue, in vitro oxidation of guinea pig brush border membrane vesicles was induced by incubation of the vesicles with ferrous sulfate and ascorbate. We found that oxidation decreased the fluidity of both the outer and inner hemileaflets, the decrease being greater in the outer leaflet. Moreover, the preferential alteration in hemileaflet fluidity was accompanied by a decrease in glucose transport. However, when membrane perturbing agents such as hexanol and A(2)C were used to restore membrane fluidity to levels comparable to controls, rates of glucose transport could not be interpreted in terms of variation of bulk membrane fluidity or variation in fluidity of any specific membrane leaflet. On the basis of these experiments, we propose that previous studies that reported coincidental alteration in membrane fluidity and glucose transport cannot be interpreted on the basis of bulk fluidity or hemileaflet fluidity.
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Affiliation(s)
- D Jourd'heuil
- Center for Cardiovascular Sciences, Albany Medical College, NY 12208, USA.
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22
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Uni Z, Geyra A, Ben-Hur H, Sklan D. Small intestinal development in the young chick: crypt formation and enterocyte proliferation and migration. Br Poult Sci 2000; 41:544-51. [PMID: 11201432 DOI: 10.1080/00071660020009054] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
1. Post-natch mucosal development was examined in the chick small intestinal epithelium using immunostaining with proliferating cell nuclear antigen (PCNA) and 5-bromo-2-deoxyuridine (BrdU). 2. On the day of hatching jejunal crypts were small and a single crypt per villus was observed. However, during the 108 h post-hatch crypts developed rapidly branching and increasing in size, cell numbers and cell size. 3. Almost all epithelial cells in the small intestine of the hatching chick were proliferating, as indicated by PCNA and BrdU, while more than 80% of proliferating cells were localised in the crypts after 108 h post hatch. 4. Estimate of villus cell transit time using BrdU was only possible from 48 h post-hatch when villus transit time was 72 h in the jejunum, whereas at 336 h transit time was 96 h. 5. In the 108 h post hatch a rapid transition occurs from total jejunal epithelial cell proliferation and immature crypts to a defined proliferative zone in the crypts, with constant division and migration.
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Affiliation(s)
- Z Uni
- Faculty of Agriculture, Food and Environmental Quality Sciences, Hebrew University of Jerusalem, Rehovot, Israel
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23
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Ljubuncic P, Said O, Ehrlich Y, Meddings JB, Shaffer EA, Bomzon A. On the in vitro vasoactivity of bile acids. Br J Pharmacol 2000; 131:387-98. [PMID: 11015287 PMCID: PMC1572336 DOI: 10.1038/sj.bjp.0703554] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We compared the vasorelaxant action of nine different bile acids and correlated their vasorelaxant activity with their individual indices for hydrophobicity or lipophilicity. Vasorelaxant activity correlated with the relative lipid solubility of bile acids with lipophilic bile acids exhibiting the greatest vasorelaxant activity with modest to no vasorelaxant activity exhibited by hydrophilic bile acids. We also investigated whether bile acid-induced vasorelaxation is mediated by antagonism of a prototypal contractile receptor, the alpha(1)-adrenoceptor, by stimulation of a bile acid surface membrane receptor, by the release of endothelium-derived relaxant factors, by promoting the generation of reactive oxygen species and increasing the extent of lipid peroxidation, or by modifying membrane fluidity. Lipophilic bile acids induce vasorelaxation possibly by antagonizing alpha(1)-adrenoceptors, a phenomenon that manifests itself as a lowering of the affinity of vascular alpha(1)-adrenoceptors. Bile acid-induced vasorelaxation was not dependent upon stimulation of a bile acid surface membrane receptor or the release of endothelium-derived relaxant factors. Lipophilic bile acids can also increase the extent of lipid peroxidation with a subtle reduction in the fluidity of rat vascular smooth muscle membranes not associated with loss of membrane cholesterol or phospholipid. We have concluded that lipophilic bile acids are non-selective vasorelaxants whose mechanism of action is a multifaceted process involving antagonism of contractile surface membrane receptors possibly effected by an increased extent of lipid peroxidation and/or membrane fluidity but occurs independent of the release of endothelial-derived relaxant factors or stimulation of a surface membrane bile acid binding site.
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Affiliation(s)
- Predrag Ljubuncic
- Department of Pharmacology, Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, P.O. Box 9647, Haifa, Israel 31096
| | - Omar Said
- Department of Pharmacology, Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, P.O. Box 9647, Haifa, Israel 31096
| | - Yaron Ehrlich
- Department of Pharmacology, Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, P.O. Box 9647, Haifa, Israel 31096
| | - Jon B Meddings
- Department of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Eldon A Shaffer
- Department of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Arieh Bomzon
- Department of Pharmacology, Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology, P.O. Box 9647, Haifa, Israel 31096
- Author for correspondence:
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24
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Abstract
AIM We examined the effect of proinflammatory and anti-inflammatory interleukins on jejunal nutrient transport and expression of the sodium-glucose linked cotransporter (SGLT-1). METHODS 3-O-methyl glucose and L-proline transport rates were examined in New Zealand White rabbit stripped, short circuited jejunal tissue. The effects of the proinflammatory cytokines interleukin (IL)-1alpha, IL-6, and IL-8, IL-1alpha plus the specific IL-1 antagonist, IL-1ra, and the anti-inflammatory cytokine IL-10 were investigated. In separate experiments, passive tissue permeability was assessed and brush border SGLT-1 expression was measured by western blot in tissues exposed to proinflammatory interleukins. RESULTS The proinflammatory interleukins IL-6, IL-1alpha, and IL-8 significantly increased glucose absorption compared with control levels. This increase in glucose absorption was due to an increase in mucosal to serosal flux. IL-1alpha and IL-8 also significantly increased L-proline absorption due to an increase in absorptive flux. The anti-inflammatory IL-10 had no effect on glucose transport. The receptor antagonist IL-1ra blocked the ability of IL-1alpha to stimulate glucose transport. IL-8 had no effect on passive tissue permeability. SGLT-1 content did not differ in brush border membrane vesicles (BBMV) from control or interleukin treated tissue. CONCLUSIONS These findings suggest that intestinal inflammation and release of inflammatory mediators such as interleukins increase nutrient absorption in the gut. The increase in glucose transport does not appear to be due to changes in BBMV SGLT-1 content.
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Affiliation(s)
- J Hardin
- Gastrointestinal Research Group, University of Calgary, Alberta, Canada
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25
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Gazawi H, Ljubuncic P, Cogan U, Hochgraff E, Ben-Shachar D, Bomzon A. The effects of bile acids on beta-adrenoceptors, fluidity, and the extent of lipid peroxidation in rat cardiac membranes. Biochem Pharmacol 2000; 59:1623-8. [PMID: 10799661 DOI: 10.1016/s0006-2952(00)00259-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bile acids have been proposed as a causative factor for the cardiomyopathy of cholestatic liver disease, since they cause negative inotropism and chronotropism and attenuate cardiac responsiveness to sympathetic stimulation. Bile acids can also modify membrane fluidity and generate reactive oxygen species (ROS). The effects of 10(-6)-10(-3) M deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) and their taurine conjugates, TDCA and TCDCA, on (1) the binding characteristics of beta-adrenoceptors, (2) membrane fluidity, and (3) the extent of lipid peroxidation in rat cardiac membranes were assessed. The results were compared to the effects of the oxidant, 10(-4)-10(-3) M hydrogen peroxide (H(2)O(2)), and the membrane-fluidizing compound, 5 x 10(-5) M 2-(2-methoxyethoxy)ethyl 8-(cis-2-n-octylcyclopropyl)octanoate (A(2)C). Cardiac beta-adrenoceptor density alone was reduced at 10(-4) M bile acid concentration while, at 10(-3) M bile acids, reductions in both receptor density and affinity were seen. At 10(-4) M H(2)O(2), receptor number and affinity were reduced, whereas A(2)C increased receptor affinity without affecting receptor density. Bile acids (10(-3) M) and 10(-4) M H(2)O(2) reduced membrane fluidity. H(2)O(2) caused a concentration-dependent increase in the extent of lipid peroxidation, whereas the bile acids and A(2)C had no effect. Bile acids (10(-4) M) reduced beta-adrenoceptor density in the absence of variations in membrane fluidity and in the extent of membrane lipid peroxidation. This result suggests that bile acids, at concentrations equivalent to the plasma/serum total or estimated free bile acid concentration, may have a possible role in the etiology of cardiomyopathy of cholestatic liver disease. At 10(-3) M bile acid concentration, beta-adrenoceptor number and affinity were adversely affected, accompanied by a decrease in membrane fluidity but without any significant increase in the extent of membrane lipid peroxidation. Although cardiac beta-adrenoceptor density and affinity and membrane fluidity were adversely affected by bile acids, the relevance of these findings to our understanding of the etiological basis of hepatic cardiomyopathy is questionable, since such concentrations exceeded the highest concentrations seen in the plasma and/or tissues of patients with cholestatic liver disease.
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Affiliation(s)
- H Gazawi
- Department of Pharmacology, Bruce Rappoport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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26
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Luxon BA, Milliano MT. Cytoplasmic transport of fatty acids in rat enterocytes: role of binding to fatty acid-binding protein. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:G361-6. [PMID: 10444450 DOI: 10.1152/ajpgi.1999.277.2.g361] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
The intracellular movement of fatty acids is thought to be facilitated through codiffusion with fatty acid-binding protein (FABP). This facilitation may occur by decreasing binding to immobile membranes, leading to faster cytoplasmic diffusion. The aims of this study were to measure the intracellular transport of 12-N-methyl-(7-nitrobenzo-2-oxa-1,3-diazol)aminostearate (NBD-stearate) in villus rat enterocytes and to determine 1) the mechanism of its cytoplasmic transport and 2) if its transport rate correlated with the known variation of FABP binding capacity along the length of the small intestine. Two-dimensional laser photobleaching was used to measure the movement of a fluorescent fatty acid NBD-stearate in enterocytes isolated from different segments of rat intestine. The fraction of NBD-stearate found in the cytostol of enterocytes was determined by differential centrifugation. Cytoplasmic transport of NBD-stearate occurred solely by diffusion and not by convection. Diffusion was homogeneous (nondirectional), consistent with isotropic diffusion. The diffusion rate varied with location along the intestine, correlating with the local FABP concentration and measured cytosolic binding. We conclude that cytoplasmic proteins like FABP promote the intracellular transport of fatty acids by enhancing their diffusive flux. We suggest that facilitation is not specific for a particular cell type but occurs in a variety of cells that transport fatty acids and may contain different types of FABP.
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Affiliation(s)
- B A Luxon
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, St. Louis University Health Sciences Center, St. Louis, Missouri 63110-0250, USA.
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27
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Donegan L, Hudye SA, Olson ME, Hardin JA, Gall DG. Effect of a dietary nonionic surfactant on small intestinal nutrient transport. Dig Dis Sci 1999; 44:1423-7. [PMID: 10489929 DOI: 10.1023/a:1026660004203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Nonionic surfactants are commonly present in many prepared foods and drug formulations as stabilizing agents. The aim of the current study was to examine the effect of the common nonionic surfactant Tween-80 on jejunal glucose transport. New Zealand White rabbits (800-1200 g) were fasted for 24 hr. Jejunal tissue was stripped and mounted in short-circuited Ussing chambers. Unidirectional 3-O-methyl glucose fluxes were determined during a 15-min basal transport period and a subsequent 15-min experimental period after the mucosal addition of Tween-80 at final concentrations of 0.001%, 0.01%, 0.05%, and 0.1%. Tween-80 at final concentrations of 0.1% and 0.05% significantly increased net 3-O-methyl glucose transport over basal levels. The increase in Jnet was due to a significant increase in the absorptive Jm-s flux. Tween-80 at 0.01% and 0.001% did not significantly alter net glucose transport although Jm-s was significantly increased in the presence of 0.01% Tween-80. Tween-80, in concentrations commonly found in prepared foods, enhances the intestinal absorption of glucose.
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Affiliation(s)
- L Donegan
- Gastrointestinal Research Group, University of Calgary, Alberta, Canada
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28
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Ismaili A, Meddings JB, Ratnam S, Sherman PM. Modulation of host cell membrane fluidity: a novel mechanism for preventing bacterial adhesion. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:G201-8. [PMID: 10409168 DOI: 10.1152/ajpgi.1999.277.1.g201] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Adhesion of bacterial enteropathogens to host mucosal surfaces is a critical primary step in the pathogenesis of diarrheal disease. We investigated the effects of altering the physical properties of eukaryotic cells on bacterial adhesion with the use of a series of three structurally dissimilar membrane fluidizers and several Escherichia coli as test strains. Lipid fluidity of the cell plasma membrane was measured by steady-state fluorescence anisotropy employing the probe 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3, 5-hexatriene. There was a dose-dependent and reversible inhibition of bacterial adhesion with increasing membrane fluidity. Time course experiments indicated that increasing membrane fluidity during the early stages of bacterial adhesion was essential for inhibition of attachment. None of the fluidizers affected the viability of either eukaryotic or prokaryotic cells. These findings demonstrate, for the first time, that changes in plasma membrane physical properties of epithelial cells can prevent microbial adhesion. This also suggests that altering the membrane properties of host cells could form a basis for novel strategies to prevent bacterial adhesion during infection in vivo.
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Affiliation(s)
- A Ismaili
- Division of Gastroenterology and Nutrition, Research Institute, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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29
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Tanii H, Horie T. Enhancement of glucose transport in small intestinal brush border membrane of retinol administered rat. Life Sci 1999; 64:1259-64. [PMID: 10227581 DOI: 10.1016/s0024-3205(99)00060-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Retinylpalmitate (200 IU/kg body weight) was administered intraperitoneally to rats once daily for 4 days. Brush border membrane vesicles (BBMVs) were prepared from small intestinal epithelium cells from along the crypt-villus axis. D-glucose uptake by BBMVs was examined under the inwardly directed Na+ gradient. The D-glucose uptake by BBMVs from the villus-tip and mid-villus cells of retinylpalmitate treated rats was significantly larger than that of control (corn oil treated) rats, respectively. Thus, retinol treatment of rats promoted the D-glucose transport in small intestinal brush border membrane. Interestingly, the enhancement of D-glucose transport was more prominent in villus-tip and mid-villus than in lower villus.
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Affiliation(s)
- H Tanii
- Laboratory of Biopharmaceutics, Faculty of Pharmaceutical Sciences, Chiba University, Japan
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30
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Hahn T, Barth S, Hofmann W, Reich O, Lang I, Desoye G. Hyperglycemia regulates the glucose-transport system of clonal choriocarcinoma cells in vitro. A potential molecular mechanism contributing to the adjunct effect of glucose in tumor therapy. Int J Cancer 1998; 78:353-60. [PMID: 9766571 DOI: 10.1002/(sici)1097-0215(19981029)78:3<353::aid-ijc16>3.0.co;2-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Glucose is taken up by tumor cells via sodium-independent facilitated diffusion along a concentration gradient. To examine the regulation of this process by substrate concentration, we investigated the effect of hyperglycemia on the glucose-transport system of choriocarcinoma-derived JAR and JEG-3 cells by culturing them for 24, 48 and 96 hr in medium containing either 5.5 (normoglycemia) or 25 (hyperglycemia) mM D-glucose, respectively. Immunocytochemically, choriocarcinoma cells expressed the high-affinity glucose transporter isoforms GLUT1 and GLUT3. Based on initial uptake measurements using 3-O-[14C]methyl-D-glucose, kinetic parameters were calculated as Km = 15 mM and Vmax = 95 fmol/sec per cell for JAR and Km = 9 mM and Vmax = 64 fmol/sec per cell for JEG-3 cells. In JAR cells cultured under hyperglycemic conditions, uptake rates were significantly increased at 15, 20 and 25 mM exogenous D-glucose concentrations as compared with normoglycemic conditions. This effect was due to an increase in Vmax, whereas Km remained unchanged. Using Northern blotting, GLUT1 mRNA levels were higher but GLUT3 transcripts were reduced upon hyperglycemia. Western blotting revealed elevated GLUT1 and GLUT3 expression under hyperglycemic conditions. Hyperglycemia did not significantly influence the glucose-transport system of JEG-3 cells. We conclude that sustained hyperglycemia stimulates the glucose-transport system of JAR, but not of JEG-3, choriocarcinoma cells in vitro due to changes in GLUT1 and GLUT3 expression levels. We speculate that this mechanism may contribute to the beneficial effects of induced hyperglycemia as an adjuvant in tumor therapy.
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Affiliation(s)
- T Hahn
- Department of Obstetrics and Gynecology, University of Graz, Austria.
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31
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Dias VC, Madsen KL, Mulder KE, Keelan M, Yatscoff RW, Thomson AB. Oral administration of rapamycin and cyclosporine differentially alter intestinal function in rabbits. Dig Dis Sci 1998; 43:2227-36. [PMID: 9790458 DOI: 10.1023/a:1026610404647] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The immunosuppressive drugs rapamycin (Rap) and cyclosporine A (CsA) are used clinically to modify or abolish immune-mediated functions. This study examined the effect of orally administered regimens of Rap, CsA, and a combination of Rap/CsA on intestinal function in male New Zealand white rabbits. Animals received oral doses of CsA (15 mg/kg/body weight/day), low-dose (LD) and high-dose (HD) Rap (0.25 or 1 mg/kg/body wt/day, respectively), or Rap/CsA (0.25 and 5 mg/kg/body wt/day, or 0.5 and 5 mg/kg/body wt/day, respectively) for 20 days. We measured in vitro uptake of nutrients and permeability, and morphometric measurements in the jejunum and ileum were made. Animals receiving HD-Rap or HD-Rap/CsA had decreased food intake, body weight, and intestinal weight, when compared with LD-Rap, LD-Rap/CsA, CsA, or controls. The maximal transport rate (Vmax) for the active jejunal uptake of D-glucose was increased in HD-Rap and CsA, but not in the HD-Rap/CsA-treated animals. The jejunal Vmax of D-glucose in the LD-Rap- or -Rap/CsA-treated animals was no different from controls. In the HD-Rap- and HD-Rap/ CsA-treated animals, jejunal rates of uptake of stearic, linoleic, and linolenic acids were reduced when compared with controls. Jejunal and ileal permeability (as assessed by the passive uptake of L-glucose, tissue conductance, and mucosal-to-serosal flux of [3H]inulin) was increased in animals treated with HD-Rap or HD-Rap/CsA, when compared with CsA or controls. These parameters of permeability were no different at lower doses of Rap or Rap/CsA. The jejunal and ileal villous surface area was increased in CsA, but decreased in HD-Rap or HD-Rap/CsA animals. Thus, HD-Rap given alone or in combination with CsA reduced body weight gain, in part due to reduced food intake and malabsorption of lipids, which was due at least in part to reduced intestinal surface area. The relevance of these findings to patients undergoing chronic immunosuppressive drug therapy needs to be established.
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Affiliation(s)
- V C Dias
- Department of Laboratory Medicine, University of Alberta, Edmonton, Canada
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32
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Hahn T, Barth S, Weiss U, Mosgoeller W, Desoye G. Sustained hyperglycemia in vitro down-regulates the GLUT1 glucose transport system of cultured human term placental trophoblast: a mechanism to protect fetal development? FASEB J 1998; 12:1221-31. [PMID: 9737725 DOI: 10.1096/fasebj.12.12.1221] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The trophoblast of human placenta is directly exposed to the maternal circulation. It forms the main barrier to maternal-fetal glucose transport. The present study investigated the effect of sustained hyperglycemia in vitro on the glucose transport system of these cells. Trophoblasts isolated from term placentas and immunopurified were cultured for 24, 48, and 96 h in DMEM containing either 5.5 (normoglycemia) or 25 mmol/l D-glucose (hyperglycemia), respectively. Initial uptake of glucose was measured using 3-O-[14C]methyl-D-glucose. Kinetic parameters were calculated as K(M) = 73 mmol/l and Vmax = 29 fmol s(-1) per trophoblast cell. Uptake rates of cells cultured under hyperglycemic conditions did not differ at exogenous D-glucose concentrations in the physiological range (1, 5.5, 10, and 15 mmol/l), but were significantly decreased by 25% (P<0.05) at diabetes-like concentrations (20 and 25 mmol/l) as compared to normoglycemic conditions. This effect was due to a decrease in Vmax (-50%), whereas K(M) remained virtually unaffected. GLUT1 mRNA levels were lower by 50% (P<0.05; Northern blotting) and GLUT1 protein was reduced by 16% (P<0.05; Western blotting) in trophoblast cells cultured under hyperglycemic vs. normoglycemic conditions. We conclude that prolonged hyperglycemia in vitro reduces trophoblast glucose uptake at substrate concentrations corresponding to blood levels of poorly controlled diabetic gravidas. This effect is due to diminished GLUT1 mRNA and protein expression in the trophoblast.
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Affiliation(s)
- T Hahn
- Department of Obstetrics and Gynecology, University of Graz Medical School, Austria.
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Zhang H, Malo C, Boyle CR, Buddington RK. Diet influences development of the pig (Sus scrofa) intestine during the first 6 hours after birth. J Nutr 1998; 128:1302-10. [PMID: 9687548 DOI: 10.1093/jn/128.8.1302] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Structural and functional responses of the intestine to colostrum, milk replacer, oral electrolyte solution and food deprivation were examined during the first 6 h after birth in pigs. Total intestinal weight, surface area and mucosal mass were highest (P < 0.05) in pigs fed colostrum. The other diet groups did not differ, except that food-deprived pigs had lower surface area than the other groups. Feeding colostrum was associated with higher mucosal protein content (P < 0.05). Total intestinal brush border membrane protein content of pigs fed milk replacer, oral electrolyte solution and food-deprived pigs were 61, 44 and 56%, respectively, of those fed colostrum (P < 0.05). Pigs fed colostrum had higher total mucosal maltase activities than those that were food deprived, and total brush border membrane activities were higher than in those fed oral electrolyte solution. Total intestinal brush border membrane aminooligopeptidase activity was higher in pigs fed colostrum than in those given oral electrolyte solution or deprived of food, but total intestinal homogenate activities did not differ among groups. Diet influenced lactase activity only in the mid-region, and sucrase was not responsive to diet. Intestinal glucose transport capacity by intact intestinal tissues did not differ among diet groups. The ability of brush border membrane vesicles to actively accumulate glucose was lost when pigs were fed colostrum and milk replacer, but not when fed oral electrolyte solution or deprived of food. Our findings reveal how diet during the first 6 h after birth influences the structure and functional characteristics of the intestine. The responses vary between brush border membrane proteins and intestinal regions, and appear to differ from those described for older animals.
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Affiliation(s)
- H Zhang
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762-5759, USA
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Sundaram U, Wisel S, Rajendren VM, West AB. Mechanism of inhibition of Na+-glucose cotransport in the chronically inflamed rabbit ileum. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:G913-9. [PMID: 9357835 DOI: 10.1152/ajpgi.1997.273.4.g913] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In a rabbit model of chronic ileal inflammation, we previously demonstrated that coupled NaCl absorption was reduced because of an inhibition of Cl-/HCO3- but not Na+/H+ exchange on the brush-border membrane (BBM) of villus cells. In this study we determined the alterations in Na+-stimulated glucose [Na+-O-methyl-D-glucose (Na+-OMG)] absorption during chronic ileitis. Na+-OMG uptake was reduced in villus cells from the chronically inflamed ileum. Na+-K+-adenosinetriphosphatase (ATPase), which provides the favorable Na+ gradient for this cotransporter in intact cells, was found to be reduced also. However, in villus cell BBM vesicles from the inflamed ileum Na+-OMG uptake was reduced as well, suggesting an effect at the level of the cotransporter itself. Kinetic studies demonstrated that Na+-OMG uptake in the inflamed ileum was inhibited by a decrease in the maximal rate of uptake for OMG without a change in the affinity. Analysis of steady-state mRNA and immunoreactive protein levels of this cotransporter demonstrates reduced expression. Thus Na+-glucose cotransport was inhibited in the chronically inflamed ileum, and the inhibition was secondary to a decrease in the number of cotransporters and not solely secondary to an inhibition of Na+-K--ATPase or altered affinity for glucose.
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Affiliation(s)
- U Sundaram
- Department of Medicine, Ohio State University School of Medicine, Columbus 43210, USA
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35
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Keelan M, Clandinin MT, Thomson ABR. Dietary lipids influence the activity of Δ5-desaturase and phospholipid fatty acids in rat enterocyte microsomal membranes. Can J Physiol Pharmacol 1997. [DOI: 10.1139/y97-125] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Keelan M, Clandinin MT, Thomson AB. Refeeding varying fatty acid and cholesterol diets alters phospholipids in rat intestinal brush border membrane. Lipids 1997; 32:895-901. [PMID: 9270983 DOI: 10.1007/s11745-997-0115-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Refeeding a diet initially given shortly after weaning results in a different adaptive change in the in vitro intestinal uptake of sugars and lipids than if the diet is given for the first time at a later age. This study was undertaken in rats to test the hypothesis that changes in nutrient uptake associated with refeeding diets containing beef tallow (S), beef tallow plus 1% cholesterol (Sc), fish oil (F), or fish oil plus cholesterol (Fc) are associated with changes in the brush border membrane (BBM) phospholipids and phospholipid fatty acids. Weanling Sprague-Dawley rats were fed ad libitum one of the four diets. At 35 d of age (about 2 wk after weaning), the rats were maintained on either the same diet used at weaning, or were switched to one of the other semisynthetic diets which were then fed for a further 7 wk. At week nine (2 + 7) the rats were either continued on the same diet or were switched back to the original diet for 2 wk (2 + 7 + 2). The groups of animals which were compared included SSSc vs. ScSSc; ScScS vs. SScS; FFFc vs. FcFFc; and FcFcF vs. FFcF. Refeeding S, Sc, F, or Fc had no effect on food consumption or on body weight gain. Refeeding Fc resulted in increased ileal BBM total phospholipids, whereas rechallenge with F resulted in a decline in the jejunal BBM ratio of phospho-lipid/cholesterol. Refeeding Sc resulted in a decrease in the ileal BBM phosphatidylcholine (PC). In rats rechallenged with Fc, there was increased ileal BBM sphingomyelin (SM), increased ileal BBM phosphatidylethanolamine (PE), decreased ileal BBM PC/PE, and an increased ileal BBM SM/PC. Refeeding had no effect on the fatty acyl constituents of the jejunal of ileal BBM PC or PE. These results suggest that there are late effects of the early introduction of dietary cholesterol on intestinal BBM phospholipid content and composition that may contribute to the previously reported changes in intestinal nutrient absorption.
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Affiliation(s)
- M Keelan
- Department of Medicine, University of Alberta, Edmonton, Canada
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Abstract
The first part of this review dealt with the physiology of glucose transport with specific emphasis on transporters of the brush border membrane (BBM) and the basolateral membrane (BLM). On the BBM, the sodium (Na)/glucose transporters (SGLT1 and SGLT2), the Na-independent transporter (GLUT5) and on the BLM the hexose transporter (GLUT2) are discussed. The molecular biology of these transporters is also reviewed. In the second part of the review, we discuss the manner in which intestinal adaptation may be modified by alterations in the diet, especially the lipid constituents, and two important examples of intestinal adaptation will be given: diabetes mellitus and inflammatory bowel disease.
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Affiliation(s)
- A B Thomson
- Division of Gastroenterology, University of Alberta, Edmonton, Canada
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Hyson DH, Thomson ABR, Keelan M, Kappagoda CT. A high cholesterol diet blocks the effect of calcium channel blockers on the uptake of sugars in rabbit intestine. Can J Physiol Pharmacol 1997. [DOI: 10.1139/y96-159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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39
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Madsen KL, Ariano D, Fedorak RN. Insulin downregulates diabetic-enhanced intestinal glucose transport rapidly in ileum and slowly in jejunum. Can J Physiol Pharmacol 1996. [DOI: 10.1139/y96-141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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40
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Affiliation(s)
- A A Izzo
- Department of Experimental Pharmacology, University of Naples Federico, Italy
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41
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Debnam ES, Unwin RJ. Hyperglycemia and intestinal and renal glucose transport: implications for diabetic renal injury. Kidney Int 1996; 50:1101-9. [PMID: 8887266 DOI: 10.1038/ki.1996.416] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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42
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Hyson DA, Thomson AB, Kappagoda CT. Calcium channel blockers modify jejunal uptake of D-galactose in rabbits. Dig Dis Sci 1996; 41:1871-5. [PMID: 8794809 DOI: 10.1007/bf02088760] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Calcium channel blockers modify the intestinal uptake of lipids. This study was undertaken to test the hypothesis that two different types of calcium channel blockers influence the uptake of D-galactose, a sugar absorbed by the sodium-dependent glucose transporter (SGLT1) in the intestinal brush border membrane. Nisoldipine (1 mg/kg/day) or verapamil (4 mg/kg/day) were given by mouth to New Zealand white rabbits for three weeks, and then the rates of uptake of varying concentrations (2-64 mM) of galactose were examined in an in vitro preparation of jejunum using the incorporation of 14C-labeled substrate into intact tissue segments. The maximal transport capacities (Vmax) for D-galactose were increased in animals given nisoldipine or verapamil, as compared to controls. The value of the apparent Michaelis constant Km* for D-galactose was higher with nisoldipine group and lower with verapamil, than in controls. The apparent passive permeability (Pd*) of D-galactose was estimated from the uptake of L-glucose: Pd* was lower with nisoldipine and higher with verapamil, as compared to controls. The effect of these drugs on sugar uptake is not due to differences in the animals' food intake, body weight gain, or mucosal surface area. Thus, the two different classes of calcium channel blockers, the dihydropyridine nisoldipine and the phenylalkylamine verapamil, have different effects on the K(m)* and Pd*, but not on the Vmax of D-galactose uptake.
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Affiliation(s)
- D A Hyson
- Department of Medicine, University of Alberta, Edmonton, Canada
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43
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Jourd'heuil D, Aspinall A, Reynolds JD, Meddings JB. Membrane fluidity increases during apoptosis of sheep ileal Peyer's patch B cells. Can J Physiol Pharmacol 1996. [DOI: 10.1139/y96-069] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Vázquez CM, Coleto R, Zanetti R, Ruiz-Gutierrez V. Increased sodium-dependent D-glucose transport in the jejunal brush-border membrane of spontaneously hypertensive rat. Pflugers Arch 1996; 432:329-35. [PMID: 8662284 DOI: 10.1007/s004240050140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The current studies explore the effect of hypertension on D-glucose transport into jejunal brush-border membrane vesicles (BBMV). Spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats, as a control group, were used. The purity of the BBMV from both groups of animals was validated by the finding that the specific activity of brush-border enzyme marker, sucrase, was severalfold greater in membrane vesicles compared with corresponding values in mucosal homogenate. D-glucose uptake was Na+ dependent in both groups of animals, with a transient increase in the intravesicular concentration of D-glucose. However, the initial rate and the magnitude of the accumulation of Na+-dependent D-glucose was significantly higher in SHR compared with WKY rats. In order to investigate the mechanism(s) for the increase in Na+-dependent D-glucose transport in SHR, several experiments were performed: (1) an experiment that indicated 22Na uptake, as an indicator for Na+ permeability, was similar between SHR and WKY rats, (2) kinetic studies that indicated that Vmax values of SHR were significantly greater that those of WKY rats. In contrast, similar Km values for glucose were found between SHR and WKY rats, (3) Na+-dependent phlorizin binding measurements that were not altered by hypertension and (4) a study of the brush-border membrane lipid composition that showed a significant increase in the free cholesterol/phospholipid ratio in SHR. We conclude that altered membrane cholesterol content and consequently altered lipid fluidity could be, at least in part, responsible for the observed increase in Na+-dependent D-glucose transport in SHR.
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Affiliation(s)
- C M Vázquez
- Departamento de Fisiología y Biología Animal, Facultad de Farmacia, C/Tramontana s/n, E-41012 Seville Spain
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45
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Gonzalez E, Vinardell MP. Ontogenetic development of proline intestinal transport in the domestic fowl. Br Poult Sci 1996; 37:383-94. [PMID: 8773847 DOI: 10.1080/00071669608417869] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
1. The proline disappearance from the jejunal and ileal lumen of chickens aged from 1 day to 15 weeks were studied using a perfusion method "in vivo". 2. A decrease in proline transport was observed from younger to older animals. The 2 intestinal segments showed different behaviours, the 1-day and 1-week-old animals showed the same value in the jejunum, whereas in the ileum a progressive decrease in proline transport was observed from the first week of life. 3. The differences observed in the 2 segments could be attributed to the different rates of growth of the jejunum and ileum with age; the jejunum showed a peak of growth in the second week of life whereas the ileum showed a peak of growth in the first week. Proline transport in the jejunum decreased until the fifth week and remained constant thereafter.
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Affiliation(s)
- E Gonzalez
- Department de Ciències Fisiològiques Humanes i de la Nutrició, Facultat de Farmàcia, Universitat de Barcelona, Spain
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46
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Abstract
BACKGROUND There is considerable interest in gene expression along the crypt-villus axis of the small intestinal epithelium, particularly in the identification of genes expressed in intestinal crypts. METHODS In an attempt to identify crypt-expressed genes, single-stranded cDNA made from normal mouse jejunal epithelium was used in subtractive hybridization against single-stranded cDNA from epithelium from which crypt cells were depleted by 2,000 rads of gamma irradiation. Partial DNA sequence and in situ hybridization of 72 resulting clones were determined. RESULTS The sequence of 45 clones matched previously published genes. Gene expression patterns fell into three categories: expression throughout the crypt-villus axis, expression restricted to the villus, and expression restricted to the crypt. Clones in the first two categories could be further divided into three subgroups: those with uniform expression, those with an increasing gradient of expression, and those with a decreasing gradient of expression along the crypt-villus axis. Twenty two clones showed a stronger expression in crypt and lower villus cells, four of these were differentially localized to the crypt. Two of the crypt localized clones were uniformly expressed throughout the crypt, expression of one was stronger in the lower crypt, and expression of the remaining clone was enhanced Paneth cells. We report the full-length cDNA sequence of the Paneth-cell-enhanced clone. CONCLUSIONS The screen isolated crypt-expressed genes that may prove useful tools in the study of crypt biology. In a companion report, we characterize one of the crypt clones.
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Affiliation(s)
- H Cheng
- Department of Anatomy and Cell Biology, University of Toronto, Ontario, Canada
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47
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Stern M, Knauss M, Stallmach A. Crypt-villus differentiation reflected by lectin and protein binding to rat small intestinal brush border membranes. Dig Dis Sci 1995; 40:2438-45. [PMID: 7587828 DOI: 10.1007/bf02063251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To compare differentiation along the crypt-villus axis in adult rats with changes observed in postnatal maturation with respect to binding capacities for lectins and food proteins, crypts and villi were isolated by in vivo perfusion and in vitro incubation. Brush border membranes were prepared from adults and newborns, and binding of 125I-labeled lectins and food proteins was assessed by airfuge ultracentrifugation. Crypt and villus membrane protein patterns looked almost identical, unlike newborn membranes. Considerable shifts in lectin binding to membranes were observed during postnatal maturation, but not in crypt-villus differentiation. For instance, fucose-specific lectin binding patterns in both preparations resembled the general adult mode. Contrary to differences in food protein binding between newborn and adult membranes, food protein binding did not show a consistent significant difference between membranes of crypt and villus origin in adult animals. In conclusion, membrane differentiation along the crypt-villus axis was found to follow a pattern dissimilar from neonatal maturation as far as protein and carbohydrate composition and food protein binding were concerned.
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Affiliation(s)
- M Stern
- Pediatric Gastroenterology Group, University Children's Clinic, Tuebingen, Germany
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48
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Munck LK. Chloride-dependent amino acid transport in the small intestine: occurrence and significance. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1241:195-213. [PMID: 7640296 DOI: 10.1016/0304-4157(95)00005-c] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The unidirectional influx of amino acids, D-glucose and ions across the brush-border membrane of the small intestine of different species has been measured in vitro with emphasis on characterization of topographic and species differences and on chloride dependence. The regional differences in transport along the small intestine are outlined and shown to be caused by variation in transport capacity, while the apparent affinity constants are unchanged. Rabbit small intestine is unique by exhibiting maximal rates of transport in the distal ileum and a very steep decline in the oral direction from where tissues are normally harvested for preparation of brush-border membrane vesicles. Transport in the guinea pig and rat is much more constant throughout the small intestine. Since the capacity of nutrient carriers is regulated by their substrates it is possible that bacterial breakdown of peptides and proteins in rabbit distal ileum increases the concentration of amino acids leading to an upregulation of the carriers. Chloride dependence is a characteristics of the carrier rather than the transported amino acid, and is used to improve the classification of amino acid carriers in rabbit small intestine. In this species the imino acid carrier, the beta-amino acid carrier, and the beta-alanine carrier, which should be renamed the B0,+ carrier, are chloride-dependent. The steady-state mucosal uptake of classical substrates for these carriers in biopsies from the human duodenum is also chloride-dependent. The carrier of beta-amino acids emerges as ubiquitous and chloride-dependent, and evidence of cotransport with both sodium and chloride is reviewed. A sodium:chloride:2-methyl-aminoisobutyric acid coupling stoichiometry of approx. 2:1:1 is suggested by ion activation studies. Direct measurements of coupled ion fluxes in rabbit distal ileum confirm that sodium, chloride and 2-methyl-aminoisobutyric acid are cotransported on the imino acid carrier with an identical influx stoichiometry. Control experiments and reference to the literature on the electrophysiology of the small intestine exclude alterations of the membrane potential as a feasible explanation of the chloride dependence. Thus, it is concluded that chloride is cotransported with both sodium and 2-methyl-aminoisobutyric acid across the brush-border membrane of rabbit distal ileum.
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Affiliation(s)
- L K Munck
- Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark
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49
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Uhing MR, Kimura RE. The effect of surgical bowel manipulation and anesthesia on intestinal glucose absorption in rats. J Clin Invest 1995; 95:2790-8. [PMID: 7769118 PMCID: PMC295964 DOI: 10.1172/jci117983] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The effects of surgical bowel manipulation and anesthesia on intestinal glucose absorption were determined in chronically catheterized rats. Total and passive rates of glucose absorption were measured using 3-O-methyl-glucose (3OMG) and L-glucose, metabolically inert analogues of D-glucose. The rates of 3OMG absorption immediately postoperative and 4 h later were 86 and 62% less than the absorption rate 6 d postoperative. The absorption rates of 3OMG 1 and 2 d postoperative were not different from 6 d postoperative. Absorption of L-glucose was not altered by bowel manipulation and anesthesia. Even after correction for the increased resistance of the unstirred water layer (UWL) after bowel manipulation, the rates of total and active intestinal glucose absorption immediately postoperative were only 11 and 15% of predicted rates of absorption. In chronically catheterized rats, > 75% of luminal 3OMG at a concentration of 400 mM was absorbed by active transport. The Km and Vmax of 3OMG active transport corrected for the resistance of the UWL were 11.3 mM and 15.6 mumoles/min, respectively. We conclude that measurements of intestinal glucose absorption performed within 24 h of surgical bowel manipulation greatly underestimate active absorption even if corrections are made to account for the increased resistance of the UWL.
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Affiliation(s)
- M R Uhing
- Department of Pediatrics, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA
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50
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Uhing MR, Kimura RE. Active transport of 3-O-methyl-glucose by the small intestine in chronically catheterized rats. J Clin Invest 1995; 95:2799-805. [PMID: 7769119 PMCID: PMC295965 DOI: 10.1172/jci117984] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A method is described for determining the fraction of intestinal 3-O-methyl-glucose (3OMG) absorption that occurs by active transport in chronically catheterized rats without the influence of anesthesia or surgical bowel manipulation. That fraction was determined by simultaneously measuring portal venous-aortic blood concentration gradients (delta C) of 3-O-methyl-glucose (3OMG) and L-glucose, metabolically inert analogues of D-glucose. 3OMG is actively and passively absorbed by the same mechanisms as D-glucose, L-glucose is only passively absorbed. The fraction of 3OMG that is actively transported was calculated from the difference between 3OMG and L-glucose absorption, divided by total 3OMG absorption. We found that more than 94% of 3-O-methyl-glucose is absorbed by active transport when luminal concentrations range from 50 to 400 mM. We conclude that in unrestrained, unanesthetized chronically catheterized rats, most 3OMG is actively absorbed by the intestine even at high luminal concentrations.
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Affiliation(s)
- M R Uhing
- Department of Pediatrics, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA
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