Stem Cell Therapy in Inflammatory Bowel Disease: A Review of Achievements and Challenges

Umbilical cord mesenchymal stem cells in ulcerative colitis treatment: efficacy and possible mechanisms

BACKGROUND

Mesenchymal stem cells (MSCs) possess powerful immunomodulatory ability. This study aimed to assess the efficacy and safety of human umbilical cord-derived mesenchymal stem cells (UMSCs) in patients with ulcerative colitis (UC) and to explore the potential mechanisms.

METHODS

This prospective, self-controlled clinical study was conducted at Henan Provincial People's Hospital. Patients with moderate-to-severe active UC, unresponsive to traditional drugs were continuously enrolled from September 2018 to March 2023. UMSCs were administered intravenously monthly for two months at a cell dosage of 1 × 106 per kg. The primary outcome was a clinical response at 2 months. The levels of cytokines and progerin in the plasma of the patients were analyzed using enzyme-linked immunosorbent assay kits, and longitudinal data was analyzed using generalized estimation equation.

RESULTS

Forty-one patients were enrolled and received UMSC therapy. At 2 months, 73.2% (30/41) of patients achieved a clinical response, and 41.5% (17/41) achieved a clinical remission. At 6 months, 2 patients were lost to follow-up; the corresponding figures were 70.0% (25/41) and 34.2% (14/41), respectively. After UMSC therapy, the Mayo score, Mayo endoscopy score, mean and maximum values of Ulcerative Colitis Endoscopic Index of Severity and Nancy index were significantly reduced compared with baseline values. Additionally, the levels of progerin and inflammatory markers, such as interleukin (IL)-1β, IL-6, IL-8, IL-12, and IL-17 A decreased, while hemoglobin, albumin, and IL-10/IL-17 A ratio increased, particularly in the response group. Multiple stepwise logistic regression analysis showed age was an independent risk factor affecting efficacy (odds ratio, 0.875 (95% confidence interval (0.787, 0.972)); the area under the receiver operating characteristic curve for age was 0.79. No serious adverse events were observed during or after UMSC therapy.

CONCLUSION

UMSCs are safe and effective for patients with UC, with age being an independent risk factor affecting efficacy. Mechanistically, UMSC treatment may ameliorate cell senescence and suppress the secretion of pro-inflammatory cytokines.

TRIAL REGISTRATION

The study was retrospectively registered at www.chictr.org.cn/ (ChiCTR1900026035) on September 18, 2019.

Optimization of transplantation methods using isolated mesenchymal stem/stromal cells: clinical trials of inflammatory bowel diseases as an example

Mesenchymal stem/stromal cells (MSCs) are distributed in various tissues and are used in clinical applications as a source of transplanted cells because of their easy harvestability. Although MSCs express numerous cell-surface antigens, single-cell analyses have revealed a highly heterogeneous cell population depending on the original tissue and donor conditions, including age and interindividual differences. This heterogeneity leads to differences in their functions, such as multipotency and immunomodulatory effects, making it challenging to effectively treat targeted diseases. The therapeutic efficacy of MSCs is controversial and depends on the implantation site. Thus, there is no established recipe for the transplantation of MSCs (including the type of disease, type of origin, method of cell culture, form of transplanted cells, and site of delivery). Our recent preclinical study identified appropriate MSCs and their suitable transplantation routes in a mouse model of inflammatory bowel disease (IBD). Three-dimensional (3D) cultures of MSCs have been demonstrated to enhance their properties and sustain engraftment at the lesion site. In this note, we explore the methods of MSC transplantation for treating IBDs, especially Crohn's disease, from clinical trials published over the past decade. Given the functional changes in MSCs in 3D culture, we also investigate the clinical trials using 3D constructs of MSCs and explore suitable diseases that might benefit from this approach. Furthermore, we discuss the advantages of the prospective isolation of MSCs in terms of interindividual variability. This note highlights the need to define the method of MSC transplantation, including interindividual variability, the culture period, and the transplantation route.

Tissue engineering and regenerative medicine approaches in colorectal surgery

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.

Prospective therapeutic targets and recent advancements in the treatment of inflammatory bowel disease

OBJECTIVE

Inflammatory Bowel Disease (IBD) poses a persistent challenge in the realm of gastroenterology, necessitating continual exploration of innovative treatment strategies. The limited efficacy and potential side effects associated with existing therapeutic modalities underscore the urgent need for novel approaches in IBD management. This study aims to examine potential therapeutic targets and recent advancements in understanding the disease's intricate pathogenesis, with a spotlight on the gut microbiome, immune dysregulation, and genetic predispositions.

METHODS

A comprehensive review was conducted to delve into the pressing demand for new avenues in IBD treatment. The study examined potential therapeutic targets such as phosphodiesterase 4 (PDE4) inhibitors, immune system modulators, Tyrosine kinase receptors (TYK), Toll-like receptors (TLRs), modulation of the gut microbiota, stem cell therapy, fibrosis management, interleukins (ILs) regulation, and oxidative stress mitigation. Additionally, advances in precision medicine, biologics, small molecule inhibitors, and microbiome modulation techniques were explored.

RESULTS

The investigation unveiled promising therapeutic targets and provided insights into recent breakthroughs that herald a transformative era in the therapeutic landscape for IBD. Advances in precision medicine, biologics, small molecule inhibitors, and the exploration of microbiome modulation techniques stood out as pivotal milestones in the field of gastroenterology.

CONCLUSIONS

The findings offer renewed hope for enhanced efficacy, reduced side effects, and improved patient outcomes in the treatment of IBD. These innovative approaches necessitate continual exploration and underscore the urgent need for novel strategies in IBD management, potentially revolutionizing the realm of gastroenterology.

The impact of interleukin-6 (IL-6) and mesenchymal stem cell-derived IL-6 on neurological conditions

Interleukin-6 (IL-6) is a versatile cytokine crucial for immune response modulation, inflammation regulation, and various physiological processes in the body. Its wide-ranging functions underscore its importance in maintaining health. Dysregulated IL-6 is closely associated with many diseases, making it a key research and therapeutic target. Elevated IL-6 levels in the central nervous system worsen neuroinflammation in neurodegenerative diseases by activating microglia and astrocytes and releasing pro-inflammatory cytokines and neurotoxic molecules. Moreover, dysregulated IL-6 weakens the blood-brain barrier, exacerbating neuroinflammation and neuronal damage by allowing peripheral immune cells and inflammatory mediators to enter the brain. Mesenchymal stem cells (MSCs) show promise in modulating neuroinflammation by regulating IL-6 levels. They effectively suppress pro-inflammatory cytokines, including IL-6, while promoting anti-inflammatory factors. This therapeutic approach highlights the importance of targeting IL-6 and other inflammatory mediators to alleviate neuroinflammation and its adverse effects on neurological disorders. This review provides a comprehensive overview of IL-6's involvement in neurological disorders, examining endogenous IL-6 and IL-6 derived from MSCs. We explore IL-6's mechanisms affecting neuronal function, survival, and immune modulation in the central nervous system. Additionally, we discuss the potential of MSC-derived IL-6 in neuroregeneration and neuroprotection. By elucidating IL-6's interplay with neurological pathologies, this review offers insights into novel therapeutic strategies targeting IL-6 signaling pathways for neurological disorders.

Mesenchymal Stromal Cells: New Generation Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, which has a high recurrence rate and is incurable due to a lack of effective treatment. Mesenchymal stromal cells (MSCs) are a class of pluripotent stem cells that have recently received a lot of attention due to their strong self-renewal ability and immunomodulatory effects, and a large number of experimental and clinical models have confirmed the positive therapeutic effect of MSCs on IBD. In preclinical studies, MSC treatment for IBD relies on MSCs paracrine effects, cell-to-cell contact, and its mediated mitochondrial transfer for immune regulation. It also plays a therapeutic role in restoring the intestinal mucosal barrier through the homing effect, regulation of the intestinal microbiome, and repair of intestinal epithelial cells. In the latest clinical trials, the safety and efficacy of MSCs in the treatment of IBD have been confirmed by transfusion of autologous or allogeneic bone marrow, umbilical cord, and adipose MSCs, as well as their derived extracellular vesicles. However, regarding the stable and effective clinical use of MSCs, several concerns emerge, including the cell sources, clinical management (dose, route and frequency of administration, and pretreatment of MSCs) and adverse reactions. This article comprehensively summarizes the effects and mechanisms of MSCs in the treatment of IBD and its advantages over conventional drugs, as well as the latest clinical trial progress of MSCs in the treatment of IBD. The current challenges and future directions are also discussed. This review would add knowledge into the understanding of IBD treatment by applying MSCs.

Heterogeneity of mesenchymal stem cells as a limiting factor in their clinical application to inflammatory bowel disease in dogs and cats

Inflammatory bowel disease (IBD) is a major subtype of chronic enteropathies in dogs and cats. Conventional drugs such as immunomodulatory medicines as glucocorticoids and/or other anti-inflammatory are mainly applied for treatment. However, these drugs are not always effective to maintain remission from IBD and are limited by unacceptable side effects. Hence, more effective and safe therapeutic options need to be developed. Mesenchymal stem cells (MSCs) are multipotent stem cells with a self-renewal capacity, and have immunomodulatory, anti-inflammatory, anti-fibrotic, and tissue repair properties. Therefore, the application of MSCs as an alternative therapy for IBD has great potential in veterinary medicine. The efficacy of adipose tissue-derived MSC (ADSC) therapy for IBD in dogs and cats has been reported, including numerous studies in animal models. However, treatment outcomes in clinical trials of human IBD patients have not been consistent with preclinical studies. MSC-based therapy for various diseases has received widespread attention, but various problems in such therapy remain, among which no consensus has been reached on the preparation and treatment procedures for MSCs, and cellular heterogeneity of MSCs may be an issue. This review describes the current status of ADSC therapy for canine and feline IBD and summarizes the cellular heterogeneity of canine ADSCs, to highlight the necessity for further reduction or elimination of MSCs heterogeneity and standardization of MSC-based therapies.

Perianal Fistula; from Etiology to Treatment - A Review

Anal fistula has been a challenging clinical issue for years due to its complex pathogenesis. The risk of frequent recurrence and incontinence complicates long-term treatment. Recent scientific literature has reviewed new techniques used for anal fistula treatment in recent years, assessing the advantages and disadvantages of each based on clinical outcomes. Although surgery is the main method used to treat anal fistula, there is no simple technique that can completely heal complex anal fistula. The surgical treatment should consider the healing outcome and the protection of anal function comprehensively. Several innovative techniques have emerged in recent years, such as combined techniques based on drainage seton and LIFT-plug, which appear to be relatively effective therapies. However, more multi-center prospective trials with long-term follow-up are needed to validate their effectiveness. In some situations, medical treatment may also be considered.

Bone marrow-derived mesenchymal stem cells mitigate chronic colitis and enteric neuropathy via anti-inflammatory and anti-oxidative mechanisms

Current treatments for inflammatory bowel disease (IBD) are often inadequate due to limited efficacy and toxicity, leading to surgical resection in refractory cases. IBD's broad and complex pathogenesis involving the immune system, enteric nervous system, microbiome, and oxidative stress requires more effective therapeutic strategies. In this study, we investigated the therapeutic potential of bone marrow-derived mesenchymal stem cell (BM-MSC) treatments in spontaneous chronic colitis using the Winnie mouse model which closely replicates the presentation and inflammatory profile of ulcerative colitis. The 14-day BM-MSC treatment regimen reduced the severity of colitis, leading to the attenuation of diarrheal symptoms and recovery in body mass. Morphological and histological abnormalities in the colon were also alleviated. Transcriptomic analysis demonstrated that BM-MSC treatment led to alterations in gene expression profiles primarily downregulating genes related to inflammation, including pro-inflammatory cytokines, chemokines and other biomarkers of inflammation. Further evaluation of immune cell populations using immunohistochemistry revealed a reduction in leukocyte infiltration upon BM-MSC treatment. Notably, enteric neuronal gene signatures were the most impacted by BM-MSC treatment, which correlated with the restoration of neuronal density in the myenteric ganglia. Moreover, BM-MSCs exhibited neuroprotective effects against oxidative stress-induced neuronal loss through antioxidant mechanisms, including the reduction of mitochondrial-derived superoxide and attenuation of oxidative stress-induced HMGB1 translocation, potentially relying on MSC-derived SOD1. These findings suggest that BM-MSCs hold promise as a therapeutic intervention to mitigate chronic colitis by exerting anti-inflammatory effects and protecting the enteric nervous system from oxidative stress-induced damage.

Advancements in hydrogel-based drug delivery systems for the treatment of inflammatory bowel disease: a review

Inflammatory bowel disease (IBD) is a chronic disorder that affects millions of individuals worldwide. However, current drug therapies for IBD are plagued by significant side effects, low efficacy, and poor patient compliance. Consequently, there is an urgent need for novel therapeutic approaches to alleviate IBD. Hydrogels, three-dimensional networks of hydrophilic polymers with the ability to swell and retain water, have emerged as promising materials for drug delivery in the treatment of IBD due to their biocompatibility, tunability, and responsiveness to various stimuli. In this review, we summarize recent advancements in hydrogel-based drug delivery systems for the treatment of IBD. We first identify three pathophysiological alterations that need to be addressed in the current treatment of IBD: damage to the intestinal mucosal barrier, dysbiosis of intestinal flora, and activation of inflammatory signaling pathways leading to disequilibrium within the intestines. Subsequently, we discuss in depth the processes required to prepare hydrogel drug delivery systems, from the selection of hydrogel materials, types of drugs to be loaded, methods of drug loading and drug release mechanisms to key points in the preparation of hydrogel drug delivery systems. Additionally, we highlight the progress and impact of the hydrogel-based drug delivery system in IBD treatment through regulation of physical barrier immune responses, promotion of mucosal repair, and improvement of gut microbiota. In conclusion, we analyze the challenges of hydrogel-based drug delivery systems in clinical applications for IBD treatment, and propose potential solutions from our perspective.

Efficacy and safety of stem cell therapy for Crohn's disease: a meta-analysis of randomized controlled trials

PURPOSE

Small-scale clinical trials have provided evidence suggesting the effectiveness of stem-cell therapy (SCT) for patients diagnosed with Crohn's disease (CD). The objective of the research was to systematically assess the effectiveness and safety of SCT for individuals diagnosed with CD through a comprehensive review and meta-analysis.

METHODS

A search was conducted in Medline (PubMed), CENTER (Cochrane Library), and Embase (Ovid) to find randomized controlled trials (RCTs) that assessed the impact of SCT on the occurrence of clinical remission (CR) and severe adverse events (SAE) among patients diagnosed with CD. The Cochrane Q test and estimation of I2 were used to assess heterogeneity among studies. After incorporating heterogeneity, a random-effects model was employed for data pooling.

RESULTS

Overall, 12 RCTs involving 632 adult patients with medically refractory CD or CD-related fistula were included. In comparison with placebo or no treatment, SCT showed a greater likelihood of CR (odds ratio [OR] 2.08, 95% CI 1.39-3.12, p < 0.001) without any notable heterogeneity (I2 = 0%). Consistent results were observed in subgroup analyses based on study design, patient diagnosis, source and type of stem cells, and follow-up durations, with all p-values for subgroup analyses being greater than 0.05. The occurrence of SAE was similar among patients assigned to SCT and the placebo/no treatment cohorts (OR 0.70, 95% CI 0.37-1.33, p = 0.28; I2 = 0%).

CONCLUSIONS

For patients with medically refractory CD or CD-related fistula, SCT may be an alternatively effective and safe treatment.

Blood-Based Biomarkers Reflecting Protease 3 and MMP-12 Catalyzed Elastin Degradation as Potential Noninvasive Surrogate Markers of Endoscopic and Clinical Disease in Inflammatory Bowel Disease

Chronic inflammation in inflammatory bowel disease (IBD) triggers significant extracellular matrix remodeling, including elastin remodeling, leading to severe clinical complications. Novel methods to assess intestinal tissue destruction may act as surrogate markers of endoscopic disease activity, relieving patients of invasive endoscopy. We explored the noninvasive blood-based biomarkers ELP-3 and ELM-12, measuring elastin degradation in IBD. In a study involving 104 Crohn's disease (CD), 39 ulcerative colitis (UC), and 29 healthy donors, we assessed these biomarkers' association with endoscopic and clinical disease activity using ELISA. Patients were evaluated based on the SES-CD and CDAI for CD patients and modified MES and partial Mayo for UC patients. ELP-3 and ELM-12 were elevated in patients with IBD. Discerning CD patients in endoscopic remission and mild from moderate to severe, ELP-3 provided an AUC of 0.69 and ELM-12 an AUC of 0.73. The ELP-3 biomarker was associated with UC patients and provided the highest diagnostic power of 0.87 for remission vs. active clinical disease. The data suggest an association of ELP-3 with active CD and ELM-12 with endoscopic remission in CD patients. Additionally, ELP-3 could identify UC patients with active clinical disease from patients in remission. The noninvasive biomarkers ELP-3 and ELM-12 could be potential surrogate biomarkers of elastin degradation and endoscopic and clinical disease markers.

Enhancement of the therapeutic efficacy of mesenchymal stem cell-derived exosomes in osteoarthritis

Osteoarthritis (OA), a common joint disorder with articular cartilage degradation as the main pathological change, is the major source of pain and disability worldwide. Despite current treatments, the overall treatment outcome is unsatisfactory. Thus, patients with severe OA often require joint replacement surgery. In recent years, mesenchymal stem cells (MSCs) have emerged as a promising therapeutic option for preclinical and clinical palliation of OA. MSC-derived exosomes (MSC-Exos) carrying bioactive molecules of the parental cells, including non-coding RNAs (ncRNAs) and proteins, have demonstrated a significant impact on the modulation of various physiological behaviors of cells in the joint cavity, making them promising candidates for cell-free therapy for OA. This review provides a comprehensive overview of the biosynthesis and composition of MSC-Exos and their mechanisms of action in OA. We also discussed the potential of MSC-Exos as a therapeutic tool for modulating intercellular communication in OA. Additionally, we explored bioengineering approaches to enhance MSC-Exos' therapeutic potential, which may help to overcome challenges and achieve clinically meaningful OA therapies.

Application of Nanoparticles in the Diagnosis of Gastrointestinal Diseases: A Complete Future Perspective

The diagnosis of gastrointestinal (GI) diseases currently relies primarily on invasive procedures like digestive endoscopy. However, these procedures can cause discomfort, respiratory issues, and bacterial infections in patients, both during and after the examination. In recent years, nanomedicine has emerged as a promising field, providing significant advancements in diagnostic techniques. Nanoprobes, in particular, offer distinct advantages, such as high specificity and sensitivity in detecting GI diseases. Integration of nanoprobes with advanced imaging techniques, such as nuclear magnetic resonance, optical fluorescence imaging, tomography, and optical correlation tomography, has significantly enhanced the detection capabilities for GI tumors and inflammatory bowel disease (IBD). This synergy enables early diagnosis and precise staging of GI disorders. Among the nanoparticles investigated for clinical applications, superparamagnetic iron oxide, quantum dots, single carbon nanotubes, and nanocages have emerged as extensively studied and utilized agents. This review aimed to provide insights into the potential applications of nanoparticles in modern imaging techniques, with a specific focus on their role in facilitating early and specific diagnosis of a range of GI disorders, including IBD and colorectal cancer (CRC). Additionally, we discussed the challenges associated with the implementation of nanotechnology-based GI diagnostics and explored future prospects for translation in this promising field.

Stem cell-derived intestinal organoids: a novel modality for IBD

The organoids represent one of the greatest revolutions in the biomedical field in the past decade. This three-dimensional (3D) micro-organ cultured in vitro has a structure highly similar to that of the tissue and organ. Using the regeneration ability of stem cells, a 3D organ-like structure called intestinal organoids is established, which can mimic the characteristics of real intestinal organs, including morphology, function, and personalized response to specific stimuli. Here, we discuss current stem cell-based organ-like 3D intestinal models, including understanding the molecular pathophysiology, high-throughput screening drugs, drug efficacy testing, toxicological evaluation, and organ-based regeneration of inflammatory bowel disease (IBD). We summarize the advances and limitations of the state-of-the-art reconstruction platforms for intestinal organoids. The challenges, advantages, and prospects of intestinal organs as an in vitro model system for precision medicine are also discussed. Key applications of stem cell-derived intestinal organoids. Intestinal organoids can be used to model infectious diseases, develop new treatments, drug screens, precision medicine, and regenerative medicine.

Creeping Fat in Crohn's Disease-Surgical, Histological, and Radiological Approaches

During the course of Crohn's disease, the response of mesenteric adipose tissue to the production of inflammatory mediators and bacterial invasion through the intestinal mucosa results in the formation of creeping fat. Creeping fat describes the arresting finger-like projections that surround the inflamed bowel. In this review, the microscopic and macroscopic features of creeping fat and histological evidence for the importance of this tissue are discussed. Moreover, the most recent insights into the radiological assessment of creeping fat in patients with Crohn's disease are reported. Advances in imaging techniques have revolutionized the possibility of visualization and quantification of adipose tissue depots with excellent accuracy. Visceral fat has been significantly correlated with various Crohn's-disease-related outcomes. Despite the difficulties in distinguishing physiologic perienteric fat from creeping fat, the growing interest in fat-wrapping in Crohn's disease has rejuvenated radiologic research. With regard to the noninvasive fat-wrapping assessment, a novel CT enterography-based mesenteric creeping fat index has been developed for the mitigation of the confounding effect of normal retroperitoneal and perienteric adipose tissue. Research on machine learning algorithms and computational radiomics in conjunction with mechanistic studies may be the key for the elucidation of the complex role of creeping fat in Crohn's disease.