Inflammatory bowel disease (IBD) can present as either Crohn's disease or ulcerative colitis. Both phenotypes are inflammatory conditions of the gastrointestinal tract. Despite scientific advances, the overall incidence and morbidity of IBD continues to increase worldwide. Fortunately, we continue to develop novel therapies, in hopes of providing safer, more effective treatment options. Such therapies include cell therapy, exosome therapy, hyperbaric oxygen therapy, and central nerve stimulation. The aim of this review is to briefly highlight each of these novel therapeutic interventions as they relate to the treatment of IBD.

Crohn's disease (CD) is a chronic, recurrent gastrointestinal disorder characterized by a complex etiology. Among its perianal complications, anal fistulas represent a challenging comorbidity. With the increase of surgical options, a comprehensive bibliometric analysis was deemed necessary to consolidate the vast array of research in this field.

We extracted 1608 articles spanning from 1 January 1994, to 1 May 2024, from the Web of Science Core Collection. Using VOSviewer, CiteSpace, and Scimago Graphica for visual analytics, we synthesized key trends across multiple bibliometric indicators, encompassing geographic and institutional contributions, individual authorship, journal prominence, citation metrics, and thematic prevalence.

From the delineated corpus, we identified publications from 325 countries and 5110 research institutions, with the US and UK at the forefront of publication volume and academic impact. The data indicated a leading role for institutions like the Cleveland Clinic and Imperial College London. "Diseases of the Colon and Rectum" emerged as a central journal due to its high publication and citation frequency. Distinctly, the analysis uncovered trending keywords, signifying the field's prioritization on surgical intervention, biologic therapy, imaging modalities, and emerging biological treatments.

Our findings elucidate a trajectory toward prominent advancements in CD fistula research. This analysis underscores the field's shift towards integrative treatment strategies, spotlighting the pressing need for comprehensive comparative studies of surgical approaches. It underscores the imperative for robust clinical trials to standardize treatments and extend care to a broader CD patient population.

Subcutaneous adipose tissue provides distinct advantages as a source of mesenchymal stem cells due to its accessibility and the ease of isolating stem cells. Human adipose stem cells, located in the stromal-vascular fraction, can be harvested using mechanical methods to produce microfragmented adipose tissue (MFAT). Local injections of MFAT have shown potential in promoting natural tissue regeneration. This review introduces the concept of MFAT, highlights its clinical applications, and explores its potential in regenerative medicine, offering insights into its role as an innovative therapeutic approach.

Bone marrow mononuclear cells (BMMNCs) are becoming a promising cell therapy in regeneration medicine. BMMNCs are now obtained by density gradient centrifugation (DGC) in clinical practice, which is complicated and greatly influenced by human manipulation.

Our objective is to develop a simple and safe method to isolate BMMNCs.

Bone marrow was aspirated from nine minipigs. The optimal hypotonic sodium chloride (NaCl) concentration was first investigated based on the BMMNCs viability and lysis efficiency tests. Afterward, three different methods (ammonium chloride (NH4Cl) lysis, hypotonic NaCl lysis, and DGC) were used for BMMNCs isolation. Nucleated cell yield, residual red blood cells (RBCs) level, BMMNCs viability, apoptotic cell percentage, and colony-forming ability were measured in three groups. Cell morphology, cell phenotype, proliferative capacity, and osteogenic, adipogenic, and chondrogenic lineage differentiation potential of the bone marrow mesenchymal stem cells (BMSCs) were compared in three groups.

0.3% NaCl lysis group had optimal cell viability and lysis efficiency and the 0.3% NaCl lysis group had higher cell yield and lower RBCs remaining in BMMNCs compared to the DGC group. The BMSCs harvested from the NH4Cl lysis group had the worst proliferation ability. The NaCl lysis group was not inferior to the other two groups in terms of other biological characteristics of BMMNCs/BMSCs.

The optimal concentration for hypotonic NaCl lysis to obtain BMMNCs is 0.3%. Compared with NH4Cl lysis and DGC, the 0.3% NaCl lysis may be a safe, appropriate, and low-cost method for BMMNCs isolation.

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The adipose-derived stromal vascular fraction (SVF) plays a crucial role in regenerative medicine owing to its regenerative and immunomodulatory properties. However, the effective utilization of SVF in therapeutic applications requires careful consideration of storage conditions to maintain cell viability.

We conducted a research on 43 patients of different ages and sexes who were older than 18 years. This study explored the impact of different temperatures (-80, -20, and 4 °C) on SVF storage in platelet-poor plasma for 1 and 6 months. SVF extracted using a semi-UNISTATION™ system was subjected to rigorous analysis of cell count and viability using a LUNA-STEM™ Dual Fluorescence Cell Counter.

The results indicated a significant correlation between the storage conditions and SVF viability. Notably, storing SVF at 4 °C demonstrated the highest cell viability and count, while -80 °C storage exhibited the least favorable outcomes. This study emphasizes the importance of minimizing storage time to preserve SVF viability, as evidenced by a decline in both cell count and viability over a 6-month period. Comparisons with the existing literature underscore the need for precise protocols for SVF storage, with considerations for temperature and cryoprotective agents. These findings provide valuable insights for developing optimal SVF storage protocols to enhance therapeutic outcomes and reduce the need for repeated adipose tissue harvesting. Despite the limitations of the study, such as the use of a cell counter instead of flow cytometry, the results establish the foundation for further research on refining SVF storage methods.

The ideal storage temperature is from 4 °C, while the length of storage time inversely affects the viability of SVF; the longer the storage time, the lower the number and the viability of SVF cells, regardless of the temperature at which they are preserved.

Post-sleeve gastrectomy fistulas are a rare but possibly severe life-threatening complication. Besides early reoperation and drainage, endoscopy is the main treatment option. According to the clinical setting, endoscopic treatment options comprise stent or clip placement. New endoscopic therapies have recently gained attention, including endoscopic vacuum therapy, VacStent therapy, endoscopic internal drainage with pigtail stents, endoscopic suturing and stem cell injection. In this narrative review, we shed light on recent literature, developments, indications and contraindications of these treatments. Intragastric gastric band migration is a rare complication after gastric band positioning. Reoperation can sometimes be difficult, especially when a gastric band has already migrated far into the stomach. Endoscopic retrieval can be a valid, non-invasive therapeutic solution. We reviewed the current literature on this matter.

Tissue engineering and regenerative medicine (TERM) is an emerging field that has provided new therapeutic opportunities by delivering innovative solutions. The development of nontraditional therapies for previously unsolvable diseases and conditions has brought hope and excitement to countless individuals globally. Many regenerative medicine therapies have been developed and delivered to patients clinically. The technology platforms developed in regenerative medicine have been expanded to various medical areas; however, their applications in colorectal surgery remain limited. Applying TERM technologies to engineer biological tissue and organ substitutes may address the current therapeutic challenges and overcome some complications in colorectal surgery, such as inflammatory bowel diseases, short bowel syndrome, and diseases of motility and neuromuscular function. This review provides a comprehensive overview of TERM applications in colorectal surgery, highlighting the current state of the art, including preclinical and clinical studies, current challenges, and future perspectives. This article synthesizes the latest findings, providing a valuable resource for clinicians and researchers aiming to integrate TERM into colorectal surgical practice.

Perianal fistulas may affect 15% to 50% of patients with Crohn's disease. Treatment is complex, requiring a multidisciplinary approach. Darvadstrocel (allogenic mesenchymal cells obtained from lipoaspirates) was approved in 2018 by the European and Spanish Agencies of Medicines and Medical Products as a treatment for fistulas in Crohn's disease. Recent guidelines from the European Crohn's and Colitis Organisation and Spanish Working Group on Crohn's Disease and Ulcerative Colitis state that darvadstrocel is effective with a favorable safety profile and a strong level of evidence (n = 2).

Presenting real-world effectiveness data for darvadstrocel in a Spanish population.

Observational retrospective cohort study with prospective data gathering.

The study was conducted at 14 institutions in Spain.

From November 2019 to April 2022, all patients (n = 73) treated with darvadstrocel in these institutions were included, fulfilling the following criteria: 1) complex fistula/s in a patient with Crohn's disease; 2) failure of conventional and antitumor necrosis factor treatment; and 3) the absence of collections of >2 cm confirmed by pelvic MRI at the time of surgery.

Darvadstrocel treatment.

Clinical response (closure of 50% or more of external openings), complete clinical closure (100% of external openings), and radiological closure (no fluid collection >2 cm, edema, or inflammation) evaluated 6 months after treatment.

Clinical response was observed in 63 patients (86.3%), complete clinical closure in 50 patients (68.5%), and radiological closure in 45 patients (69.2%). Combined clinical and radiological response was observed in 41 patients (63.1%). Not all clinically healed patients had radiological closure, and vice versa. No serious adverse events were reported.

Retrospective nature of the study.

Study results were consistent with those reported in previous clinical trials, real-world efficacy findings from the INSPIRE study (assessing darvadstrocel effectiveness in Europe, Israel, Switzerland, United Kingdom, and Japan), and previously published literature. Darvadstrocel was effective and demonstrated a favorable safety profile when used in normal clinical practice for the treatment of fistulas in Crohn's disease. See Video Abstract .

ANTECEDENTES:Las fístulas perianales pueden afectar entre el 15 y el 50% de los pacientes con enfermedad de Crohn. El tratamiento es complejo y requiere un enfoque multidisciplinario. El darvadstrocel (células mesenquimales alogénicas obtenidas a partir de lipoaspirados) fue aprobado en 2018 por las Agencias Europea y Española de Medicamentos y Productos Sanitarios como tratamiento de las fístulas en la EC. Las recientes directrices de la Organización Europea de Crohn y Colitis y del Grupo de Trabajo Español sobre la Enfermedad de Crohn y Colitis Ulcerosa afirman que darvadstrocel es eficaz con un perfil de seguridad favorable y un sólido nivel de evidencia (2).OBJETIVO:Presentar datos de eficacia real de darvadstrocel en población española.DISEÑO:Estudio de cohorte retrospectivo observacional con recopilación prospectiva de datos.ESCENARIO:14 instituciones.PACIENTES:Desde noviembre de 2019 hasta abril de 2022, se incluyeron todos los pacientes (73) tratados con darvadstrocel en estas instituciones, que cumplieron los siguientes criterios: 1) fístula/s compleja/s en un paciente con enfermedad de Crohn; 2) fracaso del tratamiento convencional y anti factor de necrosis tumoral; 3) ausencia de colecciones > 2 cm confirmada por resonancia magnética pélvica en el momento de la cirugía.INTERVENCIONES:Tratamiento con Darvadstrocel.PRINCIPALES MEDIDAS DE RESULTADO:Respuesta clínica (cierre de ≥50% de las aberturas externas), cierre clínico completo (100% de las aberturas externas) y cierre radiológico (sin acumulación de líquido >2 cm, sin edema ni inflamación) evaluados 6 meses después del tratamiento.RESULTADOS:Se observó respuesta clínica en 63 pacientes (86.3%), cierre clínico completo en 50 pacientes (68.5%) y cierre radiológico en 45 pacientes (69.2%). Se observó respuesta clínica y radiológica combinada en 41 pacientes (63.1%). No todos los pacientes clínicamente curados tuvieron cierre radiológico y viceversa. No hubo eventos adversos graves reportados.LIMITACIONES:Estudio retrospectivoCONCLUSIONES:Los resultados del estudio fueron consistentes con los informados en ensayos clínicos anteriores, los hallazgos de eficacia en el mundo real del estudio INSPIRE (que evalúa la efectividad de darvadstrocel en Europa, Israel, Suiza, el Reino Unido y Japón) y la literatura publicada anteriormente. Darvadstrocel fue eficaz y demostró un perfil de seguridad favorable cuando se utiliza en la práctica clínica habitual para el tratamiento de fístulas en la enfermedad de Crohn. (Traducción-Dr. Jorge Silva Velazco ).

Inflammatory bowel disease remains a difficult disease to effectively treat, especially fistulizing Crohn's disease. Perianal fistulas in the setting of Crohn's disease remain an area of unmet need with significant morbidity in this patient population. Up to one third of Crohn's patients will have perianal fistulizing disease and current medical and surgical interventions are of limited efficacy. Thus, most patients experience significant morbidity, narcotic use, and loss of employment and end up with multiple surgical interventions. Mesenchymal stem cells (MSCs) have shown efficacy in phase 3 clinical trials, but considerable infrastructure challenges make MSCs limited with regard to scalability in clinical practice. Extracellular vesicles, being derived from MSCs and capturing the secretome functionality of MSCs, offer similar physiological utility regarding mechanism, while also providing an off the shelf regenerative medicine product that could be widely used in daily clinical practice.

Inflammatory bowel disease (IBD) poses a significant challenge in modern medicine, with conventional treatments limited by efficacy and associated side effects, necessitating innovative therapeutic approaches. Mesenchymal stem cells (MSC) have emerged as promising candidates for IBD treatment due to their immunomodulatory properties and regenerative potential. This thesis aims to explore and compare various sources of MSC and evaluate their efficacy in treating IBD. This study comprehensively analyses MSC derived from multiple sources, including bone marrow, adipose tissue, umbilical cord, and other potential reservoirs. Core elements of this investigation include assessing differences in cell acquisition, immunomodulatory effects, and differentiation capabilities among these MSC sources, as well as comparing their clinical trial outcomes in IBD patients to their therapeutic efficacy in animal models. Through meticulous evaluation and comparative analysis, this thesis aims to elucidate disparities in the efficacy of different MSC sources for IBD treatment, thereby identifying the most promising therapeutic applications. The findings of this study are intended to advance our understanding of MSC biology and offer valuable insights for selecting the most effective MSC sources for personalized IBD therapy. Ultimately, this research endeavor will optimise therapeutic strategies for managing inflammatory bowel disease through the utilization of MSC.

The use of mesenchymal stem cells is considered a novel and promising therapeutic option for patients with perianal fistulizing Crohn's disease; however, data on its clinical application remain scarce. This multicenter nationwide study aimed to assess the clinical efficacy of mesenchymal stem cells in closing complex anal fistulas.

In this study 14 Crohn's disease patients (3 males, 11 females) with complex anal fistulas treated in 3 tertiary hospitals in Austria were included between October 2018 and April 2021. Injection of 120 million allogeneic expanded adipose-derived mesenchymal stem cells (Cx601-darvadstrocel) was performed in each patient. Closure of the external fistula opening without secretion by external manual compression was defined as treatment success.

The median age of the patient population at the time of surgery was 32 years (range 26-53 years) with a median body mass index of 21.7 kg/m2 (range 16.7-26.6 kg/m2). Of the patients 12 (86%) received monoclonal antibodies (infliximab, adalimumab, ustekinumab, vedolizumab) at the time of surgery. The median number of complex fistulas was 1.4 (range 1-2), The median operative time was 20 min (range 6-50 min) with no perioperative complications. After a median follow-up of 92 weeks, we found successful fistula closure in 57.1% (n = 8) of treated patients. The perianal disease activity index did not improve significantly from initially 7 to a median of 6 after 52 weeks (p = 0.495).

Darvadstrocel is a safe, minimally invasive surgical technique without significant perioperative complications. Clinical success can be expected in about half of the treated patients.

Stem cell transplantation is a promising therapeutic option for curing perianal fistula in Crohn's disease (CD). Anti-tumor necrotic factor (TNF) therapy combined with drainage procedure is effective as well. However, previous studies are limited to proving whether the combination treatment of biologics and stem cell transplantation improves the effect of fistula closure.

This study aimed to evaluate the long-term outcomes of stem cell transplantation and compare Crohn's perianal fistula (CPF) closure rates after stem cell transplantation with and without anti-TNF therapy, and to identify the factors affecting CPF closure and recurrence.

The patients with CD who underwent stem cell transplantation for treating perianal fistula in our institution between Jun 2014 and December 2022 were enrolled. Clinical data were compared according to anti-TNF therapy and CPF closure.

A total of 65 patients were included. The median age of females was 26 years (range: 21-31) and that of males was 29 (44.6%). The mean follow-up duration was 65.88 ± 32.65 months, and complete closure was observed in 50 (76.9%) patients. The closure rates were similar after stem cell transplantation with and without anti-TNF therapy (66.7% vs 81.6% at 3 year, P = 0.098). The patients with fistula closure had short fistulous tract and infrequent proctitis and anorectal stricture (P = 0.027, 0.002, and 0.008, respectively). Clinical factors such as complexity, number of fistulas, presence of concurrent abscess, and medication were not significant for closure. The cumulative 1-, 2-, and 3-year closure rates were 66.2%, 73.8%, and 75.4%, respectively.

Anti-TNF therapy does not increase CPF closure rates in patients with stem cell transplantation. However, both refractory and non-refractory CPF have similar closure rates after additional anti-TNF therapy. Fistulous tract length, proctitis, and anal stricture are risk factors for non-closure in patients with CPF after stem cell transplantation.

Crohn-related rectovaginal fistulas are notoriously difficult to treat. Studies of mesenchymal stem cells for the treatment of perianal Crohn fistulizing disease have largely excluded rectovaginal fistulas. The aim of this study was to determine the safety and efficacy of mesenchymal stem cells for refractory rectovaginal fistulizing Crohn disease.

A phase IB/IIA randomized control trial was performed in a 3:1, single-blinded study. Patients included were adult women with an anovaginal/rectovaginal fistula in the setting of Crohn disease. Seventy-five million mesenchymal stem cells were administered with a 22G needle after curettage and primary closure of the fistula tract at day 0 and month 3. Adverse and serious adverse events were recorded at post-procedure day 1, week 2, week 6, month 3, month 6, and month 12, along with clinical healing, magnetic resonance imaging, and patient-reported outcomes.

A total of 19 patients were enrolled and treated-15 treatment and 4 control. There were no adverse or serious adverse events related to mesenchymal stem cell therapy. At 6 months, 50% of the treatment group and 0% of the control had complete clinical and radiographic healing; 91.7% of the treatment group had improvement at 6 months with only one patient having a lack of response, whereas only 50% of the control group had improvement at 6 months.

Bone marrow-derived mesenchymal stem cells offer a safe alternative treatment approach for rectovaginal fistulas in the setting of Crohn disease. Complete healing was achieved in half of the patients.

Perianal fistulizing Crohn's disease is notoriously difficult to treat. Recent studies of mesenchymal stem cells have demonstrated safety and efficacy of this novel treatment approach. However, no studies to date have included pediatric patients. We sought to determine safety and efficacy of mesenchymal stem cells for pediatric perianal fistulizing Crohn's disease.

This was a phase I clinical trial to evaluate safety and feasibility of mesenchymal stem cells in pediatric perianal Crohn's patients 13 to 17 years of age. At the time of an exam under anesthesia, following curettage of the fistula tract and closure of the internal opening with absorbable suture, 75 million mesenchymal stem cells were administered with a 22-gauge needle. This was repeated at 3 months if complete clinical and radiographic healing were not achieved. Adverse and serious adverse events at were measured at postprocedure day 1, week 2, week 6, month 3, month 6, and month 12. Clinical healing, radiographic healing per magnetic resonance imaging, and patient-reported outcomes were measured at the same time points.

Seven pediatric patients were enrolled and treated (6 male; median age of 16.7 years). There were no adverse or serious adverse events related to the investigational product or injection procedure. At 6 months, 83% had complete clinical and radiographic healing. The perianal Crohn's Disease Activity Index, Wexner incontinence score, and Van Assche score had all decreased at 6 months.

Bone marrow-derived mesenchymal stem cells offer a safe, and likely effective, treatment approach for pediatric perianal fistulizing Crohn's disease.

The injection of allogeneic adipose tissue-derived mesenchymal stem cells (MSC) into anal fistulas in patients with Crohn's disease has never been evaluated in "real-life" conditions in France.

We prospectively studied the first patients receiving MSC injections at our center and undergoing 12 months of follow-up. The primary endpoint was the clinical and radiological response rate. The secondary endpoints were symptomatic efficacy, safety, anal continence, quality of life (Crohn's anal fistula-quality of life scale, CAF-QoL), and predictive factors of success.

We included 27 consecutive patients. The complete clinical and radiological response rates at M12 were 51.9% and 50%, respectively. The combined complete clinical-radiological response (deep remission) rate was 34.6%. No major adverse effects or changes in anal continence were reported. The perianal disease activity index decreased from 6.4 to 1.6 (p < 0.001) for all patients. The CAF-QoL score also decreased from 54.0 to 25.5 (p < 0.001). At the end of the study, M12, the CAF-QoL score was significantly lower only in patients with a complete combined clinical-radiological response relative to those without a complete clinical-radiological response (15.0 versus 32.8, p = 0.01). Having a multibranching fistula and infliximab treatment were associated with a combined complete clinical-radiological response.

This study confirms reported efficacy data for the injection of MSC for complex anal fistulas in Crohn's disease. It also shows a positive impact on the quality of life of patients, particularly those for whom a combined clinical-radiological response was achieved.

The aim of the study was to evaluate the efficacy and safety of allogeneic umbilical cord-derived mesenchymal stem cells (TH-SC01) for complex perianal fistula in patients with Crohn's disease (CD).

This was an open-label, single-arm clinical trial conducted at Jinling Hospital. Adult patients with complex treatment-refractory CD perianal fistulas (pfCD) were enrolled and received a single intralesional injection of 120 million TH-SC01 cells. Combined remission was defined as an absence of suppuration through an external orifice, complete re-epithelization, and absence of collections larger than 2 cm measured by magnetic resonance imaging (MRI) at 24 weeks after cell administration.

A total of 10 patients were enrolled. Six patients (60.0%) achieved combined remission at 24 weeks. The number of draining fistulas decreased in 9 (90.0%) and 7 (70.0%) patients at weeks 12 and 24, respectively. Significant improvement in Perianal Crohn Disease Activity Index, Pelvic MRI-Based Score, Crohn Disease Activity Index, and quality of life score were observed at 24 weeks. No serious adverse events occurred. The probability of remaining recurrence-free was 70% at week 52.

The study demonstrated that local injection of TH-SC01 cells might be an effective and safe treatment for complex treatment-refractory pfCD after conventional and/or biological treatments fail (ClinicalTrials.gov ID, NCT04939337).

The study was retrospectively registered on www.

gov (NCT04939337) on June 25, 2021.

Mesenchymal stem cells have been used for the treatment of perianal Crohn's fistulizing disease by direct injection. However, no studies to date have included patients with proctitis, anal canal involvement, and multiple branching tracts.

This study aimed to determine safety and efficacy of mesenchymal stem cells for refractory perianal Crohn's disease.

Phase IB/IIA randomized controlled trial.

Tertiary IBD referral center.

Adult Crohn's disease patients with perianal fistulizing disease.

Seventy-five million mesenchymal stem cells were administered with a 22-G needle by direct injection after curettage and primary closure of the fistula tract. A repeat injection of 75 million mesenchymal stem cells at 3 months was given if complete clinical and radiographic healing were not achieved.

Adverse and serious adverse events occurred at postprocedure day 1, week 2, week 6, month 3, month 6, and month 12. Clinical healing, radiographic healing per MRI, and patient-reported outcomes were collected at the same time points.

A total of 23 patients were enrolled and treated; 18 were treatment patients and 5 were control. There were no adverse or serious adverse events reported related to mesenchymal stem cell therapy. At 6 months, 83% of the treatment group and 40% of the control group had complete clinical and radiographic healing. The perianal Crohn's disease activity index, Wexner incontinence score, and VanAssche score had all significantly decreased in treatment patients at 6 months; none significantly decreased in the control group.

Single institution and single blinded.

Bone marrow-derived mesenchymal stem cells offer a safe and effective alternative treatment approach for severe perianal fistulizing Crohn's disease. See Video Abstract at http://links.lww.com/DCR/C128 .

ANTECEDENTES:Las células madre mesenquimales se han utilizado para el tratamiento de la enfermedad fistulizante de Crohn perianal mediante inyección dirigida. Sin embargo, ningún estudio hasta la fecha ha incluido pacientes con proctitis, afectación del canal anal y vías de ramificación múltiples.OBJETIVO:Determinar la seguridad y eficacia de las células madre mesenquimales para la enfermedad de Crohn perianal refractaria.DISEÑO:Ensayo de control aleatorizado de fase IB/IIA.AJUSTES:Centro de referencia de enfermedad inflamatoria intestinal terciaria.PACIENTES:Pacientes adultos con enfermedad de Crohn con enfermedad fistulizante perianal.INTERVENCIÓN:Se administraron 75 millones de células madre mesenquimales con una aguja 22G mediante inyección directa después del legrado y cierre primario del trayecto de la fístula. Se administró una inyección repetida de 75 millones de células madre mesenquimales a los 3 meses si no se lograba una curación clínica y radiográfica completa.PRINCIPALES MEDIDAS DE RESULTADOS:eventos adversos y adversos graves en el día 1, la semana 2, la semana 6, el mes 3, el mes 6 y el mes 12 después del procedimiento. Curación clínica, curación radiográfica por imagen de resonancia magnética y resultados informados por el paciente en los mismos puntos de tiempo.RESULTADOS:Un total de 23 pacientes fueron reclutados y tratados; 18 fueron de tratamiento y 5 de control. No se informaron eventos adversos o adversos graves relacionados con la terapia con células madre mesenquimales. A los seis meses, el 83 % del grupo de tratamiento y el 40 % del control tenían una curación clínica y radiográfica completa. El índice de actividad de la enfermedad de Crohn perianal, la puntuación de incontinencia de Wexner y la puntuación de VanAssche habían disminuido significativamente en los pacientes de tratamiento a los seis meses; ninguno disminuyó significativamente en el grupo de control.LIMITACIONES:Institución única y simple ciego.CONCLUSIONES:Las células madre mesenquimales derivadas de la médula ósea ofrecen un d tratamiento alternativo seguro y eficaz para la enfermedad de Crohn fistulizante perianal grave. Consulte Video Resumen en http://links.lww.com/DCR/C128 . (Traducción-Dr Yolanda Colorado ).

Local mesenchymal stem cell (MSC) therapy for complex perianal fistulas (PFs) has shown considerable promise. But, the long-term safety and efficacy of MSC therapy in complex PFs remain unknown.

To explore the long-term effectiveness and safety of local MSC therapy for complex PFs.

Sources included the PubMed, EMBASE, and Cochrane Library databases. A standard meta-analysis was performed using RevMan 5.3.

After screening, 6 studies met the inclusion criteria. MSC therapy was associated with an improved long-term healing rate (HR) compared with the control condition [odds ratio (OR) = 2.13; 95% confidence interval (95%CI): 1.34 to 3.38; P = 0.001]. Compared with fibrin glue (FG) therapy alone, MSC plus FG therapy was associated with an improved long-term HR (OR = 2.30; 95%CI: 1.21 to 4.36; P = 0.01). When magnetic resonance imaging was used to evaluate fistula healing, MSC therapy was found to achieve a higher long-term HR than the control treatment (OR = 2.79; 95%CI: 1.37 to 5.67; P = 0.005). There were no significant differences in long-term safety (OR = 0.77; 95%CI: 0.27 to 2.24; P = 0.64).

Our study indicated that local MSC therapy promotes long-term and sustained healing of complex PFs and that this method is safe.

The efficacy of stromal vascular fraction (SVF) treatment, or stem cell treatment, directly depends on the SVF cell count and the cells' viability. The SVF cell count and viability are in direct correlation with the adipose tissue harvesting site that yields SVF cells, making this research a contribution to developing tissue guidance.

The aim of this study was to investigate the importance of harvesting subcutaneous adipose tissue-derived SVF cells on the concentration and viability of SVF.

Adipose tissue was collected by vibration-assisted liposuction from the regions of the upper and lower abdomen, lumbar region, and inner thigh region. With the semiautomatic UNISTATION 2nd Version system, the obtained fat was chemically processed (with collagenase enzyme) and a concentrate of SVF cells was obtained by centrifugation. These samples were then analyzed with the Luna-Stem Counter device to measure the number and viability of SVF cells.

When comparing the regions of the upper abdomen, lower abdomen, lumbar region, and inner thigh, the highest concentration of SVF was found in the lumbar region, specifically at an average of 97,498.00 per 1.0 mL of concentrate. The lowest concentration was found in the upper abdominal region. When ranking the viability values, the highest cell viability of SVF was observed in the lumbar region, measuring 36.6200%. The lowest viability was found in the upper abdominal region, measuring 24.4967%.

By comparing the upper and lower abdominal, lumbar, and inner thigh regions, the authors have come to the conclusion that, on average, the largest number of cells with the highest viability was obtained from the lumbar region.

Mesenchymal stromal cells nowadays emerge as a major player in the field of regenerative medicine and translational research. They constitute, with their derived products, the most frequently used cell type in different therapies. However, their heterogeneity, including different subpopulations, the anatomic source of isolation, and high donor-to-donor variability, constitutes a major controversial issue that affects their use in clinical applications. Furthermore, the intrinsic and extrinsic molecular mechanisms underlying their self-renewal and fate specification are still not completely elucidated. This review dissects the different heterogeneity aspects of the tissue source associated with a distinct developmental origin that need to be considered when generating homogenous products before their usage for clinical applications.

Perianal Crohn's disease affects 25%-35% of patients with Crohn's disease and has proven to be one of the most difficult complications of the disease to treat. Patients with perianal Crohn's disease have lower health-related quality of life scores typically related to pain and fecal incontinence. In addition, patients with perianal Crohn's disease have higher rates of hospitalizations, surgeries, and overall healthcare costs. A multidisciplinary approach is necessary for the successful management of Crohn's disease with perianal fistula. Medical management is required to treat the underlying immune dysregulation to heal the luminal inflammation and the inflammation within the fistula tracts. Current options for medical therapy include biologics, dual therapy with thiopurines, therapeutic drug monitoring, and a close follow-up. Surgical management is critical to drain abscesses before immunosuppressive therapy and place setons when appropriate. Once the patient's inflammatory burden is well managed, definitive surgical therapies including fistulotomies, advancement flaps, and ligation of intersphincteric fistula tract procedures can be considered. Most recently, the use of stem cell therapy in the treatment of perianal fistula has given new hope to the cure of perianal fistula in Crohn's disease. This review will outline the most current data in the medical and surgical management of perianal Crohn's disease.

This study provides an overview of the development of the first drug authorized for use in cell therapy.

We analyze the case of darvadstrocel, an example of a successful cell-therapy drug used worldwide to treat Crohn's perianal fistula. A bibliographic-historical analysis of the first cellular treatment approved by the EMA, including relevant aspects concerning the authors, who were involved in the whole process. We would like to highlight the following messages: Development: The article describes the development process of the drug, from initial concept through the clinical trial phases. Learning from failure: In describing the development of darvadstrocel, the authors highlight the importance of learning from failures, which is crucial to achieving successful outcomes. Collaboration: The article underscores the need for collaboration between public and private institutions to facilitate the advancement of cell-therapy drugs and ensure efficiency while adhering to regulatory guidelines.

Regulatory requirements play a crucial role in the design and development of advanced therapies such as cell-therapy drugs. The findings of this study underscore the significance of appropriate disease application, meticulous donor selection, robust manufacturing processes, and proper therapy administration. Only by adopting these measures can cell-therapy drugs successfully complete all phases of the clinical trial process.

Encapsulated cell-based therapies for solid tumors have shown promising results in pre-clinical settings. However, the inability to culture encapsulated therapeutic cells prior to their transplantation has limited their translation into clinical settings. In this study, we created a wide variety of engineered therapeutic cells (ThC) loaded in micropore-forming gelatin methacryloyl (GelMA) hydrogel (CellDex) capsules that can be cultured in vitro prior to their transplantation in surgically debulked solid tumors. We show that both allogeneic and autologous engineered cells, such as stem cells (SCs), macrophages, NK cells, and T cells, proliferate within CellDex capsules and migrate out of the gel in vitro and in vivo. Furthermore, tumor cell specific therapeutic proteins and oncolytic viruses released from CellDex capsules retain and prolong their anti-tumor effects. In vivo, ThCs in pre-manufactured Celldex capsules persist long-term and track tumor cells. Moreover, chimeric antigen receptor (CAR) T cell bearing CellDex (T-CellDex) and human SC releasing therapeutic proteins (hSC-CellDex) capsules show therapeutic efficacy in metastatic and primary brain tumor resection models that mimic standard of care of tumor resection in patients. Overall, this unique approach of pre-manufactured micropore-forming CellDex capsules offers an effective off-the-shelf clinically viable strategy to treat solid tumors locally.

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a group of chronic inflammatory diseases of the gastrointestinal tract. Repeated inflammation can lead to complications, such as intestinal fistula, obstruction, perforation, and bleeding. Unfortunately, achieving durable remission and mucosal healing (MH) with current treatments is difficult. Stem cells (SCs) have the potential to modulate immunity, suppress inflammation, and have anti-apoptotic and pro-angiogenic effects, making them an ideal therapeutic strategy to target chronic inflammation and intestinal damage in IBD. In recent years, hematopoietic stem cells (HSCs) and adult mesenchymal stem cells (MSCs) have shown efficacy in treating IBD. In addition, numerous clinical trials have evaluated the efficiency of MSCs in treating the disease. This review summarizes the current research progress on the safety and efficacy of SC-based therapy for IBD in both preclinical models and clinical trials. We discuss potential mechanisms of SC therapy, including tissue repair, paracrine effects, and the promotion of angiogenesis, immune regulation, and anti-inflammatory effects. We also summarize current SC engineering strategies aimed at enhancing the immunosuppressive and regenerative capabilities of SCs for treating intestinal diseases. Additionally, we highlight current limitations and future perspectives of SC-related therapy for IBD.

Primary sclerosing cholangitis (PSC) is a progressive liver disease for which there is no effective therapy. Hepatocytes and cholangiocytes from a PSC patient were cocultured with mesenchymal stem cells (MSCs) to assess in vitro change. A single patient with progressive PSC was treated with 150 million MSCs via direct injection into the common bile duct. Coculture of MSCs with cholangiocytes and hepatocytes showed in vitro improvement. Local delivery of MSCs into a single patient with progressive PSC was safe. Radiographic and endoscopic evaluation showed stable distribution of multifocal structuring in the early postoperative period. MSCs may be effective for the treatment of PSC.

It is very important to generate a comprehensive assessment of the fat grafting field due to the rapid growth of scientific literature. The current study aimed to use bibliometric analysis to evaluate fat grafting research qualitatively and quantitatively and determine the research hotspots and trends in this field.

Publications on fat grafting research were extracted from the Web of Science core collection database. VOSviewer 1.6.18 was applied to perform the bibliometric analysis of these articles.

A total of 2558 studies published by 594 different journals authored by 9097 researchers were contained in this study. In the co-authorship analysis, the bulk of the retrieved studies was conducted by the USA, followed by China, Italy and Japan, while the most productive institution, journal and author were Chinese Academy of Medicine Sciences, Plastic and Reconstruction Surgery and Klinger M, respectively. In the co-cited analysis, the most top cited author, journal, organization and country were Coleman Sr, Plastic and Reconstruction Surgery, New York University and the USA, respectively. The map of keywords occurrence revealed the most active research aspects were focused on "surgery," "cell," "breast reconstruction" and "survival" and the time overlay mapping showed that the most active research hotspots were "breast reconstruction" and "retention".

The research hotspots include the following four aspects: aesthetic surgeries, cell-assisted lipotransfer, breast reconstruction and grafted fat survival. Breast fat grafting and volume retention may be trends in the future. We are willing to provide more beneficial data to contribute valuable research for the fat grafting through this study.

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Refractory perianal Crohn's disease remains notoriously difficult to treat. We developed a novel technology using a commercially available bioabsorbable fistula plug to deliver autologous adipose-derived mesenchymal stem cells.

This study aimed to assess therapeutic safety and feasibility in the completed STOMP (stem cells on matrix plugs) phase 1 clinical trial.

Prospective single-arm phase I clinical trial.

Tertiary academic medical center.

Adults (aged 18-65 y) with complex single-tract Crohn's disease perianal fistula who have failed conventional therapy were included in this study.

Autologous adipose-derived mesenchymal stem cells were isolated, ex vivo culture expanded, and seeded onto a commercially available bioabsorbable fistula plug. Six weeks later, patients returned to the operating room for removal of the seton and placement of the stem cell-loaded plug.

Patients were followed up for a total of 8 visits through 12 months. Safety was the primary end point; clinical healing and MRI response were secondary end points.

Twenty patients (12 females; mean age 36 y) were treated with the stem cell-loaded plug. Of the 20 patients enrolled, 3 were not included in the 12-month analysis because of study withdrawal. Through 12 months, no patient experienced a serious adverse event related to the stem cell-loaded plug. Four patients experienced 7 serious adverse events and 12 patients experienced 22 adverse events. Complete clinical healing occurred in 14 of 18 patients at 6 months and 13 of 17 patients at 12 months. MRI response was observed in 12 of 18 patients at 6 months.

The main limitations were the small sample size and restrictive inclusion criteria.

A stem cell-loaded plug can safely and effectively deliver cell-based therapy for patients with single-tract fistulizing perianal Crohn's disease. See Video Abstract at http://links.lww.com/DCR/C70 .

ANTECEDENTES:La enfermedad de Crohn perianal refractaria sigue siendo notoriamente difícil de tratar. Desarrollamos una tecnología novedosa utilizando un tapón de fístula bioabsorbible disponible comercialmente para administrar células madre mesenquimales derivadas de tejido adiposo autólogo.OBJETIVO:Evaluar la seguridad y viabilidad terapéutica en el ensayo finalizado STOMP.DISEÑO:Ensayo clínico prospectivo de fase I de un solo brazo.AJUSTE:Centro médico académico terciario.PACIENTES:Adultos (18-65) con fístula perianal compleja de la enfermedad de Crohn de un solo tracto que han fracasado con la terapia convencional.INTERVENCIÓN:Se aislaron células madre mesenquimales derivadas de tejido adiposo autólogo, se expandieron en cultivo ex vivo y se sembraron en un tapón de fístula bioabsorbible disponible comercialmente. Seis semanas después, los pacientes regresaron al quirófano para retirar el setón y colocar el tapón cargado de células madre.PRINCIPALES MEDIDAS DE RESULTADO:Los pacientes fueron seguidos durante un total de 8 visitas durante 12 meses. La seguridad fue el criterio principal de valoración; la curación clínica y la respuesta a la resonancia magnética fueron criterios de valoración secundarios.RESULTADOS:Veinte pacientes (12 mujeres, edad media 36 años) fueron tratados con el tapón cargado de células madre. De los 20 pacientes inscritos, tres no se incluyeron en el análisis de 12 meses porque se retiraron del estudio. A lo largo de 12 meses, ningún paciente experimentó un evento adverso grave relacionado con el tapón cargado de células madre. Cuatro pacientes experimentaron 7 eventos adversos graves y 12 pacientes experimentaron 22 eventos adversos. La curación clínica completa ocurrió en 14 de 18 pacientes a los 6 meses y en 13 de 17 pacientes a los 12 meses. La respuesta a la resonancia magnética se observó en 12 de 18 pacientes a los 6 meses.LIMITACIONES:Las principales limitaciones son el tamaño pequeño de la muestra y los criterios de inclusión restrictivos.CONCLUSIONES:Un tapón cargado de células madre se puede administrar de manera segura y efectiva, una terapia basada en células para pacientes con enfermedad de Crohn perianal fistulizante de un solo tracto. Consule Video Resumen en http://links.lww.com/DCR/C70 . (Traducción- Dr. Yesenia Rojas-Khalil ).

Acute inflammatory diseases such as acute colitis, kidney injury, liver failure, lung injury, myocardial infarction, pancreatitis, septic shock, and spinal cord injury are significant causes of death worldwide. Despite advances in the understanding of its pathophysiology, there are many restrictions in the treatment of these diseases, and new therapeutic approaches are required. Mesenchymal stem cell-based therapy due to immunomodulatory and regenerative properties is a promising candidate for acute inflammatory disease management. Based on preclinical results, mesenchymal stem cells and their-derived secretome improved immunological and clinical parameters. Furthermore, many clinical trials of acute kidney, liver, lung, myocardial, and spinal cord injury have yielded promising results. In this review, we try to provide a comprehensive view of mesenchymal stem cell-based therapy in acute inflammatory diseases as a new treatment approach.

Mesenchymal stem cells (MSCs) have been used for the treatment of perianal Crohn's fistulizing disease by direction injection. No studies to date have included patients with an ileal pouch anal anastomosis (IPAA) in situ.

A phase IB/IIA randomized control trial of bone marrow derived allogeneic MSCs via direct injection to treat adult patients with a peripouch fistula(s) was conducted. 75 million MSCs were administered with a 22G needle; repeat injection at 3 months was given if complete clinical and radiographic healing were not achieved. Adverse and serious adverse events at post procedure day 1, week 2, week 6, month 3, month 6 and month 12 were assessed. Clinical healing, radiographic healing per pelvic MRI, and patient reported outcomes were assessed at the same time points.

A total of 22 patients were enrolled and treated; 16 were treatment and 6 were control. There were no adverse or serious adverse events related to MSC therapy. At six months, 31% of the treatment group and 20% of the control had complete clinical and radiographic healing. When stratifying the treatment group into perianal (n=7) and anovaginal (n=8) fistulas, 6 month healing in the treatment groups was 57% and 0%, respectively. The perianal Crohn's disease activity index (PCDAI), Wexner incontinence score, and VanAssche score all significantly decreased in treatment patients at six months; only the PCDAI decreased in the control group.

Bone marrow derived allogeneic MSCs offer a safe and effective alternative treatment approach for peripouch fistulas in the setting of a Crohn's like phenotype of the pouch.

There have been no studies into the direct injection of mesenchymal stem cells (MSCs) for luminal ulcerative colitis (UC). Our aim was to investigate the efficacy of MSCs delivered locally via endoscopic delivery, as is done in the setting of perianal disease, to treat the local site of inflammation directly.

A phase IB/IIA randomized control clinical trial of remestemcel-L, an ex vivo expanded allogeneic bone marrow-derived MSC product, at a dose of 150 million MSCs versus placebo (2:1 fashion) delivered via direct injection using a 23-gauge sclerotherapy needle at the time of colonoscopy was designed to assess the safety and efficacy of endoscopic delivery of MSCs for UC. The main outcome measures were adverse events, Mayo score and Mayo endoscopic severity score at 2 weeks, 6 weeks and 3 months post-MSC delivery.

Six patients were enrolled and treated; four received MSCs and two placebo. All had been on prior anti-tumour necrosis factor or anti-integrin therapy. There were no adverse events related to MSCs. In the treatment group (n = 4), the Mayo endoscopic severity score decreased in all patients by 2 weeks after MSC delivery. At 3 months, all patients were extremely satisfied or satisfied with their MSC treatment based on the inflammatory bowel disease patient-reported treatment impact (IBD-PRTI), and treatment response was described as excellent or good in all patients. In the control group (n = 2), the Mayo endoscopic severity score did not increase as a result of being off alternative therapy. At 3 months, patients were dissatisfied according to the IBD-PRTI, and treatment response was poor or unchanged.

MSCs may offer a safe therapeutic option for the treatment of medically refractory UC. Early data suggest improved clinical and endoscopic scores by 2 weeks after MSC delivery.

Inflammatory bowel diseases (IBD) are chronic relapsing-remitting inflammatory diseases of the gastrointestinal tract that are typically categorized into two subtypes: Crohn's disease (CD) and ulcerative colitis (UC). Although MSCs therapy has achieved encouraging outcomes in IBD therapy, objective responses are limited in colon fibrosis stenosis owing to the complicated microenvironment of CD and MSCs heterogeneity of quality. Here, we chose IFN-γ and kynurenic acid (KYNA) to overcome the low response and heterogeneity of human adipose-derived MSCs (hADSCs) to treat IBD and expand the therapeutic effects based on the excellent ability of IFN-γ and KYNA to promote indoleamine 2,3-dioxygenase-1 (IDO-1) signaling, providing a potential protocol to treat IBD and fibrosis disease.

hADSCs were isolated, cultured, and identified from human abdominal adipose tissue. The CD pathology-like acute colitis and chronic colon fibrosis rat model was induced by 2,4,6-trinitrobenzen sulfonic acid (TNBS). hADSCs were pretreated in vitro with IFN-γ and KYNA and then were transplanted intravenously at day 1 and 3 of TNBS administration in colitis along with at day 1, 15, and 29 of TNBS administration in chronic colonic fibrosis. Therapeutic efficacy was evaluated by body weights, disease activity index, pathological staining, real-time PCR, Western blot, and flow cytometry. For knockout of IDO-1, hADSCs were transfected with IDO-1-targeting small gRNA carried on a CRISPR-Cas9-lentivirus vector.

hADSCs treated with IFN-γ and KYNA significantly upregulated the expression and secretion of IDO-1, which has effectively ameliorated CD pathology-like colitis injury and fibrosis. Notably, the ability of hADSCs with IDO-1 knockout to treat colitis was significantly impaired and diminished the protective effects of the primed hADSCs with IFN-γ and KYNA.

Inflammatory cytokines IFN-γ- and KYNA-treated hADSCs more effectively alleviate TNBS-induced colitis and colonic fibrosis through an IDO-1-dependent manner. Primed hADSCs are a promising new strategy to improve the therapeutic efficacy of MSCs and worth further research.

Inflammatory bowel disease (IBD) is a chronic, relapsing disease that severely affects patients' quality of life. The exact cause of IBD is uncertain, but current studies suggest that abnormal activation of the immune system, genetic susceptibility, and altered intestinal flora due to mucosal barrier defects may play an essential role in the pathogenesis of IBD. Unfortunately, IBD is currently difficult to be wholly cured. Thus, more treatment options are needed for different patients. Stem cell therapy, mainly including hematopoietic stem cell therapy and mesenchymal stem cell therapy, has shown the potential to improve the clinical disease activity of patients when conventional treatments are not effective. Stem cell therapy, an emerging therapy for IBD, can alleviate mucosal inflammation through mechanisms such as immunomodulation and colonization repair. Clinical studies have confirmed the effectiveness of stem cell transplantation in refractory IBD and the ability to maintain long-term remission in some patients. However, stem cell therapy is still in the research stage, and its safety and long-term efficacy remain to be further evaluated. This article reviews the upcoming stem cell transplantation methods for clinical application and the results of ongoing clinical trials to provide ideas for the clinical use of stem cell transplantation as a potential treatment for IBD.

Mesenchymal stem cells (MSCs) have been used to achieve exciting therapeutic outcomes in many animal studies and clinical trials for various autoimmune diseases, including inflammatory bowel disease (IBD). Type 1 regulatory T (Tr1) cells are the main source of interleukin (IL) 10 in the intestine. Whether Tr1 cells are involved during MSC-mediated IBD treatment is unclear. We treated a murine model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis with human umbilical cord-derived MSCs (hUCMSCs) and found that the disease severity was alleviated significantly in a dose-dependent manner. hUCMSCs increased the proportion of Tr1 cells and decreased that of T helper (Th)-1 and Th17 cells in the spleen and mesenteric lymph nodes in different stages of colitis. We found that the upregulation of Tr1 cells by hUCMSCs was abrogated after blocking indoleamine-2,3-dioxygenase (IDO), and IDO knockdown in hUCMSCs reversed the increase in Tr1 cell proportions caused by hUCMSCs in colitis. Moreover, hUCMSCs inhibited apoptosis and promoted the proliferation of Tr1 cells. Our results suggest that Tr1 cells play an important role in the amelioration of IBD by MSCs, and they are the target population for the alleviation of IBD by MSCs, providing meaningful references for the study of therapeutic mechanisms of MSCs in other inflammatory diseases.

Sleeve gastrectomy (SG) is the most performed bariatric surgery but gastric leaks following SG occur in up to 2% of cases. Regenerative medicine is emerging as a promising field offering multiple possibilities in wound healing. We studied the efficiency of locally administered mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) on leak closure following SG in rats.

The amount of PRP and MSCs extracted from one rat was analyzed and a model of gastric leak was developed in 10-week-old male Zucker rats. Twenty-four rats underwent SG fashioned with a leak. After 24 h, a second surgery was performed. The control group was treated by peritoneal lavage and drainage only while the experimental group received an additional treatment of locally administered MSCs and PRP at the leak orifice. Analysis of the leak healing process was done by an anatomopathological examination of the stomach 1, 2, 3, and 4 weeks after SG.

The extraction of MSCs and PRP from one rat was necessary for three recipients. Anatomopathological examination suggests that the closure of the leak orifice was faster in the experimental group. Statistical analysis revealed a significantly increased mucosae renewal and fibrosis score at the leak orifice after treatment with MSCs and PRP (p < 0.001).

These results suggest that PRP and MSCs may accelerate the closure of leaks following SG in rats and may become a new tool in the treatment of human gastric leaks but more research on this topic is needed to confirm these findings.

Rectovaginal fistula (RVF) occurring during the course of Crohn's disease (CD) constitutes a therapeutic challenge and is characterized by a high rate of recurrence. To optimize the outcome of CD-related RVF repair, the best conditions for correct healing should be obtained. Remission of CD should be achieved with no active proctitis, the perianal CD activity should be minimized, and local septic complications should be controlled. The objective of surgical repair is to close the fistula tract with minimal recurrence and functional disturbance. Several therapeutic strategies exist and the approach should be tailored to the anatomy of the RVF and the quality of the local supporting tissues. Herein, we review the medical and surgical management of CD-related RVF.

Regenerative medicine is an emerging therapeutic method that aims to reconstruct tissues and organs. This advanced therapeutic approach has demonstrated great potential in addressing the limitations of medical and surgical procedures for treating perineal fistula in patients with Crohn's disease. Recent developments in stem cell technology have led to a massive good manufacturing practices (GMPs) production of various stem cells, including mesenchymal and embryonic cells, along with induction of pluripotent stem cells to repair damaged tissues in the fistula. The recent advances in separation and purification of exosomes, as biologic nanovesicles carrying anti-inflammatory and regenerative agents, have made them powerful tools to treat this inflammatory disease. Further, tremendous advances in nanotechnology, biomaterials, and scaffold fabrication methods enable tissue engineering methods to synthesize tissue-like structures to assist surgical techniques. This review focuses on advanced regenerative-based methods including stem cell therapy, exosome therapy, and tissue engineering used in the treatment of perianal fistula. Relevant in vitro and in vivo studies and the latest innovations in implementation of regenerative medicine for this disease are also separately reviewed. Additionally, current challenges regarding implementation of g stem cells, exosomes, and tissue engineering methods for bridging the gaps between laboratory findings and clinic application will be discussed.

Despite current management strategies, digestive fistulae remain extremely debilitating complications associated with significant morbidity and mortality, generating a need to develop innovative therapies in these indications. A number of clinical trials and experimental studies have thus investigated the potential of stem/stromal cells (SCs) or SC-derived extracellular vesicles (EVs) administration for post-surgical and Crohn's-associated fistulae. This review summarizes the physiopathology and current standards-of-care for digestive fistulae, along with relevant evidence from animal and clinical studies regarding SC or EV treatment for post-surgical digestive fistulae. Additionally, existing preclinical models of fistulizing Crohn's disease and results of SC therapy trials in this indication will be presented. The optimal formulation and administration protocol of SC therapy products for gastrointestinal fistula treatment and the challenges for a widespread use of darvadstrocel (Alofisel) in clinical practice will be discussed. Finally, the potential advantages of EV therapy and the obstacles towards their clinical translation will be introduced.

The safety of banked human adipose-derived stem cells (hADSCs) purified by 155 mM ammonium chloride (NH₄Cl)-based erythrocyte lysis has not been evaluated. This study was conducted to determine the impact of NH₄Cl-based erythrocyte lysis on the biological characteristics of cryopreserved hADSCs. Stromal vascular fractions (SVFs) were obtained from lipoaspirates and purified with NH₄Cl-based erythrocyte lysis (lysis group) or without (nonlysis group). The hADSCs were freshly isolated (fresh group) from SVFs and/or cryopreserved for 2 weeks (cryo group). The morphologies, immunophenotypes, viability, apoptosis, and growth kinetics of each group were compared. The cell cycle and differentiation capacity assays were performed in both cryopreserved groups. All groups showed similar cell morphology, immunological phenotypes, and viability. However, the main effect of lysis and its interaction with cryopreservation were observed when early apoptosis was regarded as a dependent variable in two-way repeated-measures analysis of variance. After cryopreservation, significant growth retardation and S-phase fraction reduction were observed in lytic hADSCs compared with those in nonlytic hADSCs. No significant differences in the adipogenic and osteogenic differentiation capacities were found between the two groups. Although NH₄Cl-based erythrocyte lysis did not affect the cell morphology, immunological phenotypes, viability, and adipogenic and osteogenic differentiation capacities of cryopreserved hADSCs, exposure to NH₄Cl-based erythrocyte lysis or its synergistic action with cryopreservation may induce apoptosis and inhibit the proliferation and mitosis of cryopreserved hADSCs. These results indicate that NH₄Cl-based erythrocyte lysis is not suitable for high-quality banked collection of hADSCs for future clinical applications. Further development of safe, convenient, and cost-effective purification methods of hADSCs is warranted.

Tissue reconstruction and regeneration represent one of the greatest challenges in any surgical field. Regenerative medicine combined with stem cell-based therapy is a novel and promising field of medicine. Stem cells possess the ability to differentiate into specialized cells and to decrease inflammation and therefore can play a role in repair or regeneration of damaged tissues. Colorectal surgery often deals with infected, poorly vascularized, radiated, and inflamed tissue, as well as instances where imperfect healing might have grave implications. This problem has led researchers to study utilizing stem cells in many colorectal conditions, such as anastomotic healing, perianal fistulae, rectovaginal fistulae, anal fissure, and fecal incontinence. The purpose of this review was to discuss prominent studies that explored stem cells utilization in treating different colorectal pathologies.