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Fang YJ, Hsieh HH, Lin HJ, Lin CL, Lee WY, Chen CH, Tsai FJ, You BJ, Tien N, Lim YP. Relationship between venous thromboembolism and inflammatory bowel disease in Taiwan: a nationwide retrospective cohort study. BMC Cardiovasc Disord 2025; 25:153. [PMID: 40050756 PMCID: PMC11884027 DOI: 10.1186/s12872-025-04600-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2024] [Accepted: 02/21/2025] [Indexed: 03/10/2025] Open
Abstract
BACKGROUND Inflammation significantly influences thrombosis development, with venous thromboembolism (VTE) risk linked to various systemic inflammatory diseases, but not fully established in inflammatory bowel disease (IBD). Using a population-based cohort study conducted in Taiwan, we investigated the impact of IBD on the risk of VTE, deep vein thrombosis (DVT), and pulmonary embolism (PE), as well as the impact of anti-IBD treatments. METHODS A study was conducted on a cohort of patients with IBD diagnosed between 2010 and 2019 using the National Health Insurance database. The risks of VTE, DVT, and PE, as well as anti-IBD treatment use, were examined using Cox proportional hazard regression analysis. RESULTS The overall number of person-years recorded for 12,126 patients with IBD (mean age: 49.18 years; 55.31% male) and 12,126 controls (mean age: 49.19 years; 55.31% male) was 64,057 and 72,056, with a follow-up duration for the two cohorts was 5.28 and 5.94 years, respectively. After adjusting for age, gender, and comorbidities, the adjusted hazard ratios (aHRs) of VTE, DVT, and PE in patients with IBD were 5.58 [95% confidence interval (CI) = 3.97-7.87], 5.48 (95% CI = 3.83-7.86), and 4.96 (95% CI = 2.00-12.35) times higher, respectively, than those in the control cohort. Male patients with IBD and those under the age of 50 were more likely to develop VTE (aHR = 8.54, 95% CI = 2.00-12.35; aHR = 15.75, 95% CI = 5.73-43.26, respectively). Compared to the cohort of patients with IBD receiving no treatment, patients receiving anti-IBD treatments did not show a significant change in the risk of developing VTE. Additionally, compared to the IV steroid cohort, patients with IBD who only used oral steroids had a substantially lower incidence of VTE, particularly with average doses of ≤ 80 mg (aHR = 0.24, 95% CI = 0.10-0.59). CONCLUSION Patients with IBD are at an increased risk of developing VTE, particularly DVT and PE. While our study found that anti-IBD treatments did not significantly alter this risk, proactive management of associated factors and close monitoring remains essential for preventing VTE in this population. Identifying and addressing specific associated factors should be prioritized in clinical practice to mitigate the heightened risk of VTE in IBD patients.
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Affiliation(s)
- Yi-Jen Fang
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung-Hsing University, Taichung, Taiwan
- Digestive Disease Center, Show Chwan Memorial Hospital, Changhua, Taiwan
| | - Hui-Hsia Hsieh
- Department of Pharmacy, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 66, Sec. 1, Fengxing Rd., Tanzi Dist, Taichung, 427213, Taiwan.
- Department of Pharmacy, College of Pharmacy, China Medical University, No. 100, Sec. 1, Jingmao Rd., Beitun Dist, Taichung City, 406040, Taiwan.
| | - Heng-Jun Lin
- Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan
| | - Cheng-Li Lin
- Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan
| | - Wan-Yi Lee
- Department of Pharmacy, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 66, Sec. 1, Fengxing Rd., Tanzi Dist, Taichung, 427213, Taiwan
- Department of Pharmacy, College of Pharmacy, China Medical University, No. 100, Sec. 1, Jingmao Rd., Beitun Dist, Taichung City, 406040, Taiwan
| | - Chi-Hua Chen
- Department of Pharmacy, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 66, Sec. 1, Fengxing Rd., Tanzi Dist, Taichung, 427213, Taiwan
| | - Fuu-Jen Tsai
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan
- Division of Medical Genetics, China Medical University Children's Hospital, Taichung, Taiwan
- Department of Biotechnology and Bioinformatics, Asia University, Taichung, Taiwan
| | - Bang-Jau You
- Department of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan
| | - Ni Tien
- Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
| | - Yun-Ping Lim
- Department of Pharmacy, College of Pharmacy, China Medical University, No. 100, Sec. 1, Jingmao Rd., Beitun Dist, Taichung City, 406040, Taiwan.
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan.
- Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.
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Bhardwaj A, Singh A, Midha V, Sood A, Wander GS, Mohan B, Batta A. Cardiovascular implications of inflammatory bowel disease: An updated review. World J Cardiol 2023; 15:553-570. [PMID: 38058397 PMCID: PMC10696203 DOI: 10.4330/wjc.v15.i11.553] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 10/22/2023] [Accepted: 11/08/2023] [Indexed: 11/23/2023] Open
Abstract
Emerging data highlights the heightened risk of atherosclerotic cardiovascular diseases (ASCVD) in patients with chronic inflammatory disorders, particularly those afflicted with inflammatory bowel disease (IBD). This review delves into the epidemiological connections between IBD and ASCVD, elucidating potential underlying mechanisms. Furthermore, it discusses the impact of current IBD treatments on cardiovascular risk. Additionally, the cardiovascular adverse effects of novel small molecule drugs used in moderate-to-severe IBD are investigated, drawing parallels with observations in patients with rheumatoid arthritis. This article aims to comprehensively evaluate the existing evidence supporting these associations. To achieve this, we conducted a meticulous search of PubMed, spanning from inception to August 2023, using a carefully selected set of keywords. The search encompassed topics related to IBD, such as Crohn's disease and ulcerative colitis, as well as ASCVD, including coronary artery disease, cardiovascular disease, atrial fibrillation, heart failure, conduction abnormalities, heart blocks, and premature coronary artery disease. This review encompasses various types of literature, including retrospective and prospective cohort studies, clinical trials, meta-analyses, and relevant guidelines, with the objective of providing a comprehensive overview of this critical intersection of inflammatory bowel disease and cardiovascular health.
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Affiliation(s)
- Arshia Bhardwaj
- Department of Gastroenterology, Dayanand Medical College and Hospital, Punjab, Ludhiana 141001, India
| | - Arshdeep Singh
- Department of Gastroenterology, Dayanand Medical College and Hospital, Punjab, Ludhiana 141001, India
| | - Vandana Midha
- Department of Internal Medicine, Dayanand Medical College and Hospital, Punjab, Ludhiana 141001, India
| | - Ajit Sood
- Department of Gastroenterology, Dayanand Medical College and Hospital, Punjab, Ludhiana 141001, India
| | - Gurpreet Singh Wander
- Department of Cardiology, Dayanand Medical College and Hospital, Punjab, Ludhiana 141001, India
| | - Bishav Mohan
- Department of Cardiology, Dayanand Medical College and Hospital, Punjab, Ludhiana 141001, India
| | - Akash Batta
- Department of Cardiology, Dayanand Medical College and Hospital, Punjab, Ludhiana 141001, India.
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Massironi S, Mulinacci G, Gallo C, Viganò C, Fichera M, Villatore A, Peretto G, Danese S. The oft-overlooked cardiovascular complications of inflammatory bowel disease. Expert Rev Clin Immunol 2023; 19:375-391. [PMID: 36722283 DOI: 10.1080/1744666x.2023.2174971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/13/2023] [Accepted: 01/27/2023] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Inflammatory bowel disease (IBD) may be associated with several extraintestinal comorbidities, including cardiovascular disease (CVD). Chronic inflammation is recognized as an important factor in atherogenesis, thrombosis, and myocarditis. AREAS COVERED IBD patients may be at increased risk for developing early atherosclerosis, cardiovascular events, peripheral artery disease, venous thromboembolism, myocarditis, and arrhythmias. Anti-tumor necrosis factor agents and thiopurines have been shown to have a protective effect against acute arterial events, but more research is needed. However, an increased risk of venous thromboembolism and major cardiovascular events has been described with the use of Janus kinase inhibitors. EXPERT OPINION CVD risk is slightly increased in patients with IBD, especially during flares. Thromboprophylaxis is strongly recommended in hospitalized patients with active disease as the benefit of anticoagulation outweighs the risk of bleeding. The pathogenetic relationship between CVD and IBD and the impact of IBD drugs on CVD outcomes are not fully elucidated. CVD risk doesn't have the strength to drive a specific IBD treatment. However, proper CVD risk profiling should always be done and the best strategy to manage CVD risk in IBD patients is to combine appropriate thromboprophylaxis with early and durable remission of the underlying IBD.
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Affiliation(s)
- Sara Massironi
- Division of Gastroenterology, and Center for Autoimmune Liver Diseases, European Reference Network on Hepatological Diseases (ERN RARE-LIVER), Fondazione IRCCS San Gerardo dei Tintori, University of Milano-Bicocca School of Medicine, Monza, Italy
| | - Giacomo Mulinacci
- Division of Gastroenterology, and Center for Autoimmune Liver Diseases, European Reference Network on Hepatological Diseases (ERN RARE-LIVER), Fondazione IRCCS San Gerardo dei Tintori, University of Milano-Bicocca School of Medicine, Monza, Italy
| | - Camilla Gallo
- Division of Gastroenterology, and Center for Autoimmune Liver Diseases, European Reference Network on Hepatological Diseases (ERN RARE-LIVER), Fondazione IRCCS San Gerardo dei Tintori, University of Milano-Bicocca School of Medicine, Monza, Italy
| | - Chiara Viganò
- Division of Gastroenterology, and Center for Autoimmune Liver Diseases, European Reference Network on Hepatological Diseases (ERN RARE-LIVER), Fondazione IRCCS San Gerardo dei Tintori, University of Milano-Bicocca School of Medicine, Monza, Italy
| | - Maria Fichera
- Division of Gastroenterology, and Center for Autoimmune Liver Diseases, European Reference Network on Hepatological Diseases (ERN RARE-LIVER), Fondazione IRCCS San Gerardo dei Tintori, University of Milano-Bicocca School of Medicine, Monza, Italy
| | - Andrea Villatore
- Myocarditis Disease Unit, Department of Cardiac Electrophysiology and Arrhythmology, IRCCS Ospedale San Raffaele, Milan, Italy, and Vita-Salute San Raffaele University, Milan, Italy
| | - Giovanni Peretto
- Myocarditis Disease Unit, Department of Cardiac Electrophysiology and Arrhythmology, IRCCS Ospedale San Raffaele, Milan, Italy, and Vita-Salute San Raffaele University, Milan, Italy
| | - Silvio Danese
- Gastroenterology and Endoscopy, IRCCS Ospedale San Raffaele, Milan, Italy, and Vita-Salute San Raffaele University, Milan, Italy
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Olivera PA, Zuily S, Kotze PG, Regnault V, Al Awadhi S, Bossuyt P, Gearry RB, Ghosh S, Kobayashi T, Lacolley P, Louis E, Magro F, Ng SC, Papa A, Raine T, Teixeira FV, Rubin DT, Danese S, Peyrin-Biroulet L. International consensus on the prevention of venous and arterial thrombotic events in patients with inflammatory bowel disease. Nat Rev Gastroenterol Hepatol 2021; 18:857-873. [PMID: 34453143 PMCID: PMC8395387 DOI: 10.1038/s41575-021-00492-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/05/2021] [Indexed: 12/11/2022]
Abstract
Patients with inflammatory bowel disease (IBD) are at increased risk of thrombotic events. Therapies for IBD have the potential to modulate this risk. The aims of this Evidence-Based Guideline were to summarize available evidence and to provide practical recommendations regarding epidemiological aspects, prevention and drug-related risks of venous and arterial thrombotic events in patients with IBD. A virtual meeting took place in May 2020 involving 14 international IBD experts and 3 thrombosis experts from 12 countries. Proposed statements were voted upon in an anonymous manner. Agreement was defined as at least 75% of participants voting as 'fully agree' or 'mostly agree' with each statement. For each statement, the level of evidence was graded according to the Scottish Intercollegiate Guidelines Network (SIGN) grading system. Consensus was reached for 19 statements. Patients with IBD harbour an increased risk of venous and arterial thrombotic events. Thromboprophylaxis is indicated during hospitalization of any cause in patients with IBD. Disease activity is a modifiable risk factor in patients with IBD, and physicians should aim to achieve deep remission to reduce the risk. Exposure to steroids should be limited. Antitumour necrosis factor agents might be associated with a reduced risk of thrombotic events.
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Affiliation(s)
- Pablo A Olivera
- Gastroenterology Section, Department of Internal Medicine, Centro de Educación Médica e Investigaciones Clínicas (CEMIC), Buenos Aires, Argentina
| | - Stephane Zuily
- Vascular Medicine Division and Regional Competence Center for Rare Vascular and Systemic Autoimmune Diseases, Centre Hospitalier Régional Universitaire de Nancy, Vandoeuvre-lès-Nancy, France
- University of Lorraine, INSERM, DCAC, Nancy, France
| | - Paulo G Kotze
- IBD outpatient clinics, Colorectal Surgery Unit, Catholic University of Paraná (PUCPR), Curitiba, Brazil
| | | | - Sameer Al Awadhi
- Gastroenterology Division, Rashid Hospital, Dubai Health Authority, Dubai, UAE
| | - Peter Bossuyt
- Imelda GI Clinical Research Center, Imelda General Hospital, Bonheiden, Belgium
| | - Richard B Gearry
- Department of Medicine, University of Otago, Christchurch, New Zealand
| | - Subrata Ghosh
- NIHR Biomedical Research Centre, University of Birmingham and University Hospitals NHS Foundation Trust, Birmingham, UK
| | - Taku Kobayashi
- Center for Advanced IBD Research and Treatment, Kitasato University, Kitasato Institute Hospital, Tokyo, Japan
| | | | - Edouard Louis
- Department of Gastroenterology, CHU Liège University Hospital, Liège, Belgium
| | - Fernando Magro
- Department of Gastroenterology, Centro Hospitalar São João, Porto, Portugal
| | - Siew C Ng
- Department of Medicine and Therapeutics, Institute of Digestive Disease, LKS Institute of Health Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Alfredo Papa
- Division of Internal Medicine and Gastroenterology, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
- Catholic University of Rome, Rome, Italy
| | - Tim Raine
- Department of Gastroenterology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | | | - David T Rubin
- University of Chicago Medicine, Inflammatory Bowel Disease Center, Chicago, IL, USA
| | - Silvio Danese
- IBD Center, Department of Gastroenterology, Humanitas Clinical and Research Center - IRCCS, Milan, Italy
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Milan, Italy
| | - Laurent Peyrin-Biroulet
- Department of Gastroenterology and INSERM NGERE U1256, University Hospital of Nancy, University of Lorraine, Vandoeuvre-lès-Nancy, France.
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Anticoagulant therapy for venous thromboembolism in patients with inflammatory bowel disease. Eur J Gastroenterol Hepatol 2018; 30:526-530. [PMID: 29462026 DOI: 10.1097/meg.0000000000001084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND There is lack of evidence to guide the type, intensity, and the duration of anticoagulation following venous thromboembolism (VTE) in patients with inflammatory bowel disease (IBD). PATIENTS AND METHODS Registro Informatizado Enfermedad Trombo Embólica (RIETE) is an ongoing, multicenter, observational registry of consecutive patients with symptomatic, objectively confirmed, acute VTE. We used the RIETE database to compare the rate of VTE recurrences and major bleeding during the course of anticoagulation in noncancer patients with or without IBD. RESULTS As of October 2014, 41 927 patients without active cancer have been recruited in RIETE. Of these, 265 (0.63%) had IBD and 85 (32%) had the VTE during an acute flare. The duration of anticoagulation was similar in patients with VTE during an acute flare (8.3±8.8 months), in remission (9.4±11.5 months), or without IBD (10.0±12.8 months). The rate of VTE recurrences [7.25, 95% confidence interval (CI): 1.46-21.2; 8.84, 95% CI: 3.23-19.2; and 5.85, 95% CI: 5.46-6.26 per 100 patient-years, respectively] and major bleeding (7.25, 95% CI: 1.46-21.2; 2.95, 95% CI: 0.33-10.6; and 4.79, 95% CI: 4.44-5.15, respectively) were similar in all three subgroups. Propensity score matching analysis confirmed the absence of differences in the rate of VTE recurrences (rate ratio: 1.16, 95% CI: 0.54-2.47) or major bleeding (rate ratio: 0.84, 95% CI: 0.31-2.23) between patients with or without IBD. CONCLUSION Therapeutic anticoagulation for patients with IBD and VTE is as safe and effective as for those with VTE without IBD.
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Tian LL, Huang LY. Inflammatory bowel disease and thromboembolic events. Shijie Huaren Xiaohua Zazhi 2017; 25:589-595. [DOI: 10.11569/wcjd.v25.i7.589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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
Thromboembolism (TE) is an extraintestinal manifestation (EIM) of inflammatory bowel disease (IBD). According to previous pathological reports, the incidence of IBD complicated with TE is as high as 41%. However, this EIM is often overlooked. This review summarizes the results of the relevant clinical studies to date, analyzes the potential prothrombotic risk of IBD drug therapy, and discusses the current status on the treatment and prevention of TE, with an aim to provide a comprehensive reference for clinical work.
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Abstract
Thrombosis in inflammatory bowel disease (IBD) is an increasingly noted extraintestinal manifestation with high morbidity and mortality. While controlling the activity of the disease with the appropriate therapy, thromboembolism prophylaxis should be applied to all patients. All common risk factors for thromboembolism are also valid for patients with IBD; however, it is clear that uncontrolled disease and hospitalization are major disease-specific risk factors for venous thromboembolism in patients with IBD. Pharmacological thromboprophylaxis with currently available anticoagulants does not increase the risk of further bleeding in patients with IBD with mild-to-moderate bleeding. In severe bleeding or with increased risk of further bleeding due to other comorbid conditions, thromboprophylaxy with mechanical methods should be the treatment option. Whether thrombosis is the cause or the result of intestinal inflammation remains to be elucidated, and other issues in the etiology, such as the role of intestinal flora in thrombosis pathogenesis, will be the subject of future studies.
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Zitomersky NL, Verhave M, Trenor CC. Thrombosis and inflammatory bowel disease: a call for improved awareness and prevention. Inflamm Bowel Dis 2011; 17:458-70. [PMID: 20848518 DOI: 10.1002/ibd.21334] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Thrombotic complications in patients with inflammatory bowel disease (IBD) are common and require improved awareness and prevention. In this review the interface between IBD and thrombosis is discussed, with emphasis on risk assessment and data to aid clinical decision making. Thromboembolic complications are 3-fold more likely in IBD patients than controls and the relative risk exceeds 15 during disease flares. Improved assessment of thrombosis risk for an individual patient includes thorough personal and family history and awareness of prothrombotic medications and lifestyle choices. Patients with the highest risk of thrombosis are those with active colonic disease, personal or strong family history of thrombosis, and those with significant acquired risk factors. Combined risk factors or hospitalization should prompt mechanical thromboprophylaxis. Indications for prophylactic anticoagulation are not defined currently by clinical studies, especially in pediatric patients, although some groups now advocate prophylactic anticoagulation for all hospitalized IBD patients and even some outpatients with disease flares. Thrombosis management requires a multidisciplinary therapeutic approach to balance anticoagulation and bleeding risk. While bleeding may occur with anticoagulation in IBD, data and experience indicate that therapeutic heparin is safe and bleeding manifestations can be managed supportively in most patients. Until prospective trials of prophylactic anticoagulation are published, management of thrombotic risk and prophylaxis in IBD will remain a clinical challenge.
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Affiliation(s)
- Naamah L Zitomersky
- Division of Gastroenterology, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Fareed J, Bacher P, Messmore HL, Walenga JM, Hoppensteadt DA, Strano A, Pifarre R. Pharmacological modulation of fibrinolysis by antithrombotic and cardiovascular drugs. Prog Cardiovasc Dis 1992; 34:379-98. [PMID: 1579631 DOI: 10.1016/0033-0620(92)90006-l] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- J Fareed
- Department of Pathology, Loyola University Medical Center, Maywood, IL 60153
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Fischer-Nielsen A, Poulsen HE, Loft S. 8-Hydroxydeoxyguanosine in vitro: effects of glutathione, ascorbate, and 5-aminosalicylic acid. Free Radic Biol Med 1992; 13:121-6. [PMID: 1516838 DOI: 10.1016/0891-5849(92)90073-p] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Oxidative DNA damage, as expressed by 8-hydroxydeoxyguanosine (8-OHdG), was investigated in calf thymus DNA exposed to either ultraviolet radiation or to FeCl2/H2O2 in a Fenton-like reaction. The influence of iron (absent in the UV system and present in the FeCl2/H2O2 system) and pH (7.4 and 4.0) on the effect of glutathione (GSH), ascorbate, and 5-aminosalicylic acid (5-ASA, a drug used in the treatment of chronic inflammatory bowel diseases) was examined in these systems. Without iron, all three compounds considerably reduced 8-OHdG formation (i.e., acted as scavengers), while in the presence of iron salts, 8-OHdG formation was accelerated (except for GSH at pH 7.4), i.e., the compounds acted as prooxidants. This effect was augmented at low pH. The prooxidant property of 5-ASA may have implications for its clinical use. Maximum scavenging effect for all the compounds investigated was obtained at much lower doses than the maximum enhancing effect. This demonstrates that to the end of oxy-radical scavenging, the concentration of the GSH, ascorbate, and 5-ASA, respectively, should be chosen to obtain maximum antioxidant effect and minimum prooxidant effects. The significance of this finding for the selection of antioxidant dose is important but remains to be investigated further.
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