Systematic review with meta-analysis: Safety and efficacy of local injections of mesenchymal stem cells in perianal fistulas

Darvadstrocel for complex perianal fistulas in Crohn's disease: A systematic review and meta-analysis

BACKGROUND

Local injection of darvadstrocel, a suspension of expanded adipose-derived allogenic mesenchymal stem cells, has been used for treatment-refractory perianal fistulas in Crohn's disease (CD).

OBJECTIVE

This study aimed to investigate efficacy and safety of darvadstrocel for complex perianal fistulas in CD.

METHODS

A systematic search was conducted through April 2024 in relevant databases for observational studies evaluating darvadstrocel. A random-effects meta-analysis model was used to calculate the pooled effect sizes (proportions or incidence rates [IRs]) with 95% confidence intervals (CIs) of effectiveness and safety outcomes. The risk of bias was evaluated using the Joanna Briggs Institute Critical Appraisal Tool. The I2 value assessed heterogeneity. Sensitivity and subgroup analyses were also conducted.

RESULTS

Twelve studies were included with 595 patients. The pooled rate of patients achieving clinical remission, defined as fistula healing, was 68.1% at month 6 (95% CI 63.4-72.7) and 77.2% (95% CI 70.1-83.8) at month 12. Combined remission, defined as clinical remission and absence of collections >2 cm confirmed by magnetic resonance imaging, was reported in 60.6% and in 69.7% of patients at months 6 and 12, respectively. The rate of patients with treatment failure, defined as no clinical remission at the last follow-up (mean 18.7 months; SD 9.9), was 34.5%. Failure rate was independent of follow-up time (p = 0.85). For effectiveness outcomes, between-study heterogeneity was negligible. Subgroup analysis indicated that none of the covariates modified the treatment effect. Pooled IRs per 100 patient-years of adverse events (AE), serious AEs, perianal abscesses, and reoperations were 19.6, 3.2, 16.9 and 7.1, respectively.

CONCLUSION

Evidence from observational studies supports the efficacy and safety of darvadstrocel for complex perianal fistulas in CD. Studies have reported high fistula healing rates that can be sustained long-term in most patients, with negligible between-study heterogeneity, as well as a favorable safety profile.

Acceptability of Allogeneic Mesenchymal Stromal Cell-Based Tissue Engineering for the Treatment of Periodontitis: A Qualitative Study in France

INTRODUCTION AND AIMS

Periodontitis, the main cause of tooth loss in adults, is a public health concern; its incidence increases with age, and its prevalence increases with increasing life expectancy of the population. Innovative therapies such as cell therapy represent promising future solutions for guided tissue regeneration. However, these therapies may be associated with fears and mistrust from the general public. The aim of this study was to estimate the acceptability of an advanced therapy medicinal product combining allogeneic mesenchymal stromal cells from adipose tissue with a natural fibrin hydrogel in the treatment of periodontitis.

METHODS

The methodology was based on a qualitative study conducted through semi-structured interviews with patients followed for periodontitis in the Oral Medicine Department of the Toulouse University Hospital, Toulouse, France. Qualitative studies are essential methodologies to understand the patterns of health behaviours, describe illness experiences, and design health interventions in a humanistic and person-centred way of discovering.

RESULTS

Eleven interviews (with 4 men and 7 women) were required to reach thematic saturation. Analysis allowed 4 main themes to emerge: (1) perception of new treatments, science, and caregivers; (2) conditions that the treatment must meet; (3) patient perception of the disease; and (4) factors related to the content of the treatment.

CONCLUSIONS

Patients find cell therapy for periodontitis to be acceptable. If they express a need to be informed about the benefit/risk ratio, they are not particularly worried about side effects of the treatment, for either allogeneic or blood-derived products. Periodontitis is a prototypical model of chronic inflammatory pathology and is multitissular, with hard- and soft-tissue lesions. In a patient-centred approach, the success of cell therapy will require a bilateral, informed decision, taking into account potential therapeutic effectiveness and patient expectations for regeneration.

Unveiling advanced strategies for therapeutic stem cell interventions in severe burn injuries: a comprehensive review

This comprehensive review explores the complex terrain of stem cell therapies as a potential therapeutic frontier in the healing of complicated burn wounds. Serious tissue damage, impaired healing processes, and possible long-term consequences make burn wounds a complex problem. An in-depth review is required since, despite medical progress, existing methods for treating severe burn wounds have significant limitations. Burn wounds are difficult to heal because they cause extensive tissue damage. The challenges of burn injury-induced tissue regeneration and functional recovery are also the subject of this review. Although there is a lot of promise in current stem cell treatments, there are also some limitations with scalability, finding the best way to transport the cells, and finding consistent results across different types of patients. To shed light on how to improve stem cell interventions to heal severe burn wounds, this review covers various stem cell applications in burn wounds and examines these obstacles. To overcome these obstacles, one solution is to enhance methods of stem cell distribution, modify therapies according to the severity of the burn, and conduct more studies on how stem cell therapy affects individual patients. Novel solutions may also be possible through the combination of cutting-edge technologies like nanotechnology and biotechnology. This review seeks to increase stem cell interventions by analyzing present challenges and suggesting strategic improvements. The goal is to provide a more effective and tailored way to repair serious burn wounds.

Mesenchymal stem cell therapy for Crohn's perianal fistula-a real-world experience

AIM

Remission rates of medically and surgically treated complex perianal fistulas in Crohn's disease are low. Recently, trials have demonstrated the potential for long-term remission with local injection of allogeneic adipose-derived mesenchymal stem cells (darvadstrocel). Our aim was to analyse outcomes from our real-world experience with this new treatment.

METHODS

All patients with Crohn's disease suffering complex perianal fistulas who consecutively underwent administration of darvadstrocel at two centres were followed up and evaluated. Patients were assessed for clinical remission, response, failure, and any complications during follow-up. The results of all patients with a minimum of 3 months' follow-up are presented.

RESULTS

Thirty-three patients with Crohn's disease and complex perianal fistulas were included. Of these, 20 (61%) experienced clinical remission that was maintained for a mean follow-up of 14 (3-32) months. A total of 24 of 33 (73%) experienced at least 3 months of clinical remission, with four later having recurrence (3-12 months). Among the remaining nine patients who did not experience clinical remission, two (6%) had partial remission (such as one of two fistulas closing), two (6%) showed signs of response but not remission, and five (15%) showed no signs of healing. The mean time to maintained clinical remission was 6 weeks (range 2 weeks to 6 months), and there were no severe adverse events.

CONCLUSION

In this real-world experience, treatment of Crohn's disease complex perianal fistulas with darvadstrocel had a 61% success rate for maintained clinical remission.

Mesenchymal stem cells transplantation for perianal fistulas: a systematic review and meta-analysis of clinical trials

BACKGROUND

Perianal fistulas, characterised as granulomatous inflammation of fistulas around the anal canal, are associated with significant morbidity resulting in a negative impact on quality of life and a tremendous burden to the healthcare system. Treatment of anal fistulas usually consists of anal surgery; however, results of closure rates are not satisfactory especially with complex perianal fistulas, after which many patients may suffer from anal incontinence. Recently, the administration of mesenchymal stem cells (MSCs) has shown promising efficacy. Herein, we aim to explore whether MSCs are effective for complex perianal fistulas and if they have either short-term, medium-term, long-term or over-long-term efficacy. Additionally, we want to elucidate whether factors such as drug dosage, MSC source, cell type, and disease aetiology influence treatment efficacy. We searched four online databases and analysed data based on information within the clinical trials registry. The outcomes of eligible trials were analysed with Review Manager 5.4.1. Relative risk and related 95% confidence interval were calculated to compare the effect between the MSCs and control groups. In addition, the Cochrane risk of bias tool was applied to evaluate the bias risk of eligible studies. Meta-analyses showed that therapy with MSCs was superior to conventional treatment for complex perianal fistulas in short-, long- and over-long-term follow-up phases. However, there was no statistical difference in treatment efficacy in the medium term between the two methods. Subgroup meta-analyses showed factors including cell type, cell source and cell dosage were superior compared to the control, but there was no significant difference between different experimental groups of those factors. Besides, local MSCs therapy has shown more promising results for fistulas as a result of Crohn's Disease (CD). Although we tend to maintain that MSCs therapy is effective for cryptoglandular fistulas equally, more studies are needed to confirm this conclusion in the future.

SHORT CONCLUSION

MSCs Transplantation could be a new therapeutic method for complex perianal fistulas of both cryptoglandular and CD origin showing high efficacy in the short-term to over-long-term phases, as well as high efficacy in sustained healing. The difference in cell types, cell sources and cell dosages did not influence MSCs' efficacy.

Autologous fat graft injections for the treatment of perianal fistulas in Crohn's disease: a systematic review and single-arm meta-analysis

BACKGROUND

Crohn's perianal fistulas are often refractory to standard management. Fat graft injections are hypothesised to improve fistula healing rates. We evaluated the treatment efficacy of fat graft injections for Crohn's perianal fistulas in a systematic review (PRISMA).

METHODS

We completed database searches of MEDLINE (Ovid), Embase, and PubMed. All studies published in English in full text or abstract, from January 2001 to August 2021, evaluating fat graft injections for Crohn's perianal fistulas were selected. Included randomized controlled trials, single-arm intervention trials, cohort studies, and case series; excluded single case reports. Primary outcome was pooled clinical healing, defined as non-draining treated fistulas, or closure, defined as closure of treated fistulas. Secondary outcomes were clinical healing, clinical closure, radiologic response, and adverse events.

RESULTS

Of 1258 publications identified, 891 articles were assessed for eligibility, and 107 relevant for manuscript review. Forty-nine patients received fat graft injections for Crohn's perianal fistulas across four single-arm intervention trials. Clinical healing or closure was achieved in 74% in a pooled single-arm meta-analysis (95% confidence interval: 57%, 85%), with moderate heterogeneity between studies. Clinical healing was achieved in 20% and 60% at 3 and 12 months, respectively. Clinical closure was achieved in 83% at 6 months. Variable parameters were used to define radiologic response, with success rates from 20% to 67%. Minimal adverse events were reported.

CONCLUSION

Fat graft injections show promise as a novel treatment for Crohn's perianal fistulas in this systematic review and meta-analysis. Assessment in controlled matched studies is warranted.

The Intersection of Human and Veterinary Medicine-A Possible Direction towards the Improvement of Cell Therapy Protocols in the Treatment of Perianal Fistulas

The effective treatment of perianal fistulizing Crohn's disease is still a challenge. Local administration of mesenchymal stromal cells (MSCs) is becoming a part of accepted treatment options. However, as a fledgling technique, it still can be optimized. A new trend in translational research, which is in line with "One Health" approach, bases on exploiting parallels between naturally occurring diseases affecting humans and companion animals. Canine anal furunculosis (AF) has been indicated as condition analogous to human perianal Crohn's disease (pCD). This narrative review provides the first comprehensive comparative analysis of these two diseases based on the published data. The paper also outlines the molecular mechanisms of action of MSCs which are likely to have a role in modulating the perianal fistula niche in humans, and refers them to the current knowledge on the immunomodulatory properties of canine MSCs. Generally, the pathogenesis of both diseases shares main determinants such as the presence of genetic predispositions, dysregulation of immune response and the relation to intestine microbiota. However, we also identified many aspects which should be further specified, such as determining the frequency of true fistulas formation in AF patients, elucidating the role of TNF and Th17 pathway in the pathogenesis of AF, or clarifying the role of epithelial-to-mesenchymal transition phenomenon in the formation of canine fistulae. Nevertheless, the available data support the hypothesis that the results from testing cell therapies in dogs with anal furunculosis have a significant translational value in optimizing MSC transplants procedures in pCD patients.

INSPECT: A Retrospective Study to Evaluate Long-term Effectiveness and Safety of Darvadstrocel in Patients With Perianal Fistulizing Crohn's Disease Treated in the ADMIRE-CD Trial

BACKGROUND

The efficacy of a single administration of darvadstrocel (expanded allogeneic adipose-derived mesenchymal stem cells) for treating complex perianal fistulas in patients with Crohn's disease was demonstrated in a randomized, double-blind trial (ADMIRE-CD [Adipose Derived Mesenchymal Stem Cells for Induction of Remission in Perianal Fistulizing Crohn\'s Disease] trial). The current chart review study (INSPECT [A retrospectIve chart review study evaluatINg the longer-term effectiveneSs of darvadstrocel in PatiEnts who CompleTed ADMIRE-CD]) evaluated the longer-term effectiveness and safety of darvadstrocel.

METHODS

Eligible patients had completed at least 52 weeks in the ADMIRE-CD trial. Data on clinical remission and fistula relapse outcomes were collected retrospectively at 104 and 156 weeks after treatment. Adverse events of special interest (tumorigenicity and ectopic tissue formation) were collected up to 208 weeks after treatment.

RESULTS

Eighty-nine patients were included (43 darvadstrocel patients, 46 control subjects). At 52, 104, and 156 weeks posttreatment, clinical remission was observed in 29 (67.4%) of 43, 23 (53.5%) of 43, and 23 (53.5%) of 43 darvadstrocel-treated patients, compared with 24 (52.2%) of 46, 20 (43.5%) of 46, and 21 (45.7%) of 46 control subjects, respectively. In patients with clinical remission at week 52, this remission was sustained at 104 and 156 weeks after treatment in 19 (65.5%) of 29 and 16 (55.2%) of 29 darvadstrocel-treated patients and in 17 (70.8%) of 24 and 13 (54.2%) of 24 control subjects, respectively. Time to fistula relapse and incidence of fistula relapse or new fistula occurrence were not significantly different between groups. Tumorigenicity was reported for 1 (2.2%) patient in the control group (malignant epidermoid carcinoma). No ectopic tissue formation was reported.

CONCLUSIONS

Real-world follow-up of patients from the ADMIRE-CD trial indicates that clinical remission of complex perianal fistulas can be sustained in the long term irrespective of whether it is achieved through darvadstrocel administration or maintenance treatment regimens and confirms a favorable long-term safety profile of darvadstrocel.

Mesenchymal Stem Cell Therapy Awareness, Knowledge, and Use for the Treatment of Fistulizing Crohn's Disease: An International Survey Among Gastroenterologists and Colorectal Surgeons

Introduction

Mesenchymal stem (or stromal) cells are a promising therapy for the treatment of various inflammatory and autoimmune diseases. This study aimed to understand awareness, knowledge, and perception of mesenchymal stem cells among gastroenterologists and colorectal surgeons, with particular focus on the perianal fistulizing Crohn’s disease indication.

Methods

A web-based questionnaire was distributed to currently practicing and registered gastroenterologists and colorectal surgeons across 15 countries in North America, Europe, and Asia Pacific.

Results

Of 146 clinicians, 115 (79%) were aware of mesenchymal stem cells. The majority were moderately to largely interested in this therapy (87%), willing to use it in patients with perianal fistulizing Crohn’s disease (82%), and believed it addresses unmet needs for these patients (93%). However, most responders reported having limited or no knowledge of this therapy (64%) or its efficacy (51%), safety (53%), and mechanism of action (65%) in perianal fistulizing Crohn’s disease. Many clinicians (46%) also expressed concerns about using this therapy in these patients. Attending discussions and presentations on mesenchymal stem cells and seeing more patients with Crohn’s disease were associated with increased awareness (both P < 0.001).

Conclusions

Many clinicians demonstrated an interest in mesenchymal stem cells in general and a willingness to use them to treat perianal fistulizing Crohn’s disease, but this survey showed suboptimal knowledge of what mesenchymal stem cells are and how they work in this indication. This may explain clinicians’ concerns about use of this therapy and calls out for education activities.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02113-5.

Stem cell transplantation for induction of remission in medically refractory Crohn's disease

BACKGROUND

Crohn's disease (CD) is an inflammatory bowel disease that causes inflammation and stricture, of any part of the mucosa and the gut wall. It forms skip lesions, sparing the areas in between the affected parts of the gastrointestinal tract. Crohn's disease could have one of three complications; fistula, intestinal obstruction due to stricture, or gastrointestinal inflammation presenting as severe diarrhoea. Stem cell therapy (SCT) is an innovative treatment that has been recently used in CD. The exact role of SCT in CD is still unclear. Stem cells modify the immunity of the patients or act as a "reset tool" for the immune system as in the case of systemically-injected stem cells, or regenerate the affected area of necrotic and inflammatory tissue as in the case of local injection into the lesion. Stem cells are a wide variety of cells including pluripotent stem cells or differentiated stem cells. The hazards range from rejection to symptomatic manifestations as fever or increase infection.  OBJECTIVES: The objective of this Cochrane systematic review is to assess the effects of stem cell transplantation compared to standard of care alone or with placebo on efficacy and safety outcomes in patients with refractory CD.

SEARCH METHODS

We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and clinical trial registries (Clinicaltrials.gov, World Health Organization-International Clinical Trials Registry Platform WHO ICTRP) from inception to 19 March 2021, without any language, publication year, or publication status restrictions. In addition, we searched references of included studies and review articles for further references. An update of the published studies was done during the writing of the review.

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) that assessed the effectiveness and safety of SCT in refractory CD versus standard care alone (control) or with placebo.

DATA COLLECTION AND ANALYSIS

Two review authors (SEN and SFA) independently screened the studies retrieved from the search results for inclusion, extracted data and assessed the risk of bias. Any disagreement was resolved through a consensus between the authors. We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We conducted our search on 19 March 2021 and identified 639 records. We added two records by a manual search of the published reviews on the topic to a total of 641 records. The Covidence program removed 125 duplicates making a total of 516 reports. Two review authors (SEN and SFA) screened titles and abstracts and excluded 451 records with the remaining 65 for full-text records screened independently by the two authors; only 18 studies were considered for inclusion.  We included seven RCTs with a total of 442 participants for the meta-analysis. The intervention group included 234 patients, and the control group included 208 patients. Nine trials are ongoing and, two abstracts are awaiting classification. All patients in the control and intervention groups received the standard therapy for CD. Only three studies used blinding methods for the control group in the form of a placebo, with one study of the three stated that the blinding method was inefficient. The patients and personnel were aware of the intervention in the rest of the four studies as they were open-label trials. However, the effect of unblinding was balanced by the low risk of detection bias in five of the included studies. The evidence is uncertain about the effect of SCT on achieving clinical remission as compared to control/placebo (risk ratio (RR) 1.88, 95% Confidence Interval (CI) 0.80 to 4.41; 3 studies; low-certainty evidence). The evidence is very uncertain about the effect of SCT on achieving Crohn's Disease Activity Index (CDAI) <150 at 24 weeks compared to control (RR1.02 95% CI 0.67 to 1.56; 4 studies; very-low certainty evidence). SCT is likely to achieve fistula closure as compared to the control/placebo both in the short term (RR 1.48, 95% CI 1.12 to 1.96); low-certainty evidence) and in the long term (RR 1.42, 95% CI 1.09 to 1.87; 4 studies; low-certainty evidence) follow-up. The evidence is very uncertain about the effect of SCT to cause no difference in the number of total adverse events as compared to the control/placebo (RR 0.99, 95% CI [0.88 to  1.13); 4 studies; very-low-certainty evidence). However, SCT is likely to increase the number of serious adverse events as compared to the control/placebo (RR 1.22, 95% CI 0.88 to 1.67; 7 studies; low-certainty evidence). The evidence is very uncertain about the effect of SCT to decrease the withdrawal due to adverse events as compared to the control/placebo (RR 0.78, 95% CI 0.32 to 1.89; 3 studies; very-low certainty evidence). Funding by pharmaceutical companies was found in three studies, with one including more than 50% of our studied population.

AUTHORS' CONCLUSIONS

SCT shows an uncertain effect on clinical remission with low certainty of evidence. SCT shows an uncertain effect on CDAI score to reach <150 after 24 weeks of treatment, with very low certainty evidence. SCT shows beneficial effects on fistula-closure during short and long-term follow-up with low-certainty evidence in both outcomes. There was no change in the total number of adverse events with SCT as compared to control, with very low certainty evidence. While there was a moderate effect on increasing the number of serious adverse events in the SCT group, as compared to the control with low-certainty evidence. Withdrawal due to adverse events was slightly higher in the control group with very low certainty evidence. All the participants were refractory to standard medical treatment, but the number of participants was small, this may limit the generalizability of the results. Further research is needed for validation. More objective outcomes are needed in the assessment of stem cell effectiveness in the treatment of Crohn's disease, especially the intestinal CD subtype; with standardization of the dose, methods of stem cell preparation, route of administration, and inclusion criteria to the studies to achieve clear results.

Mesenchymal Stem Cells and PRP Therapy Favorize Leak Closure After Sleeve Gastrectomy in Zucker Rats

INTRODUCTION

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Mesenchymal Stem Cells for Cryptoglandular Anal Fistula: Current State of Art

Anal fistula is a common disease that needs surgical treatment to be resolved. Despite a variety of surgical options, the major problem is still to cure complex fistulas without any recurrence in the long-term follow-up but, at the same time, to avoid an impairment of continence. In recent years, one solution has been the application of mesenchymal stem cells derived from adipose tissue, especially in association with other treatments, such as the use of fibrin glue or the previous application of a seton. Their initial use in fistulas associated with Crohn's disease has shown encouraging results. In this non-systematic review our aim is to analyze the use in cryptoglandular fistulas: the rate of healing is not so high, and the number of studies is limited. Therefore, further randomized controlled trials are needed to establish their efficacy in the case of complex cryptoglandular anal fistulas and their possible complications.

Regenerative medicine for digestive fistulae therapy: Benefits, challenges and promises of stem/stromal cells and emergent perspectives via their extracellular vesicles

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.

Current Overview on the Use of Mesenchymal Stem Cells for Perianal Fistula Treatment in Patients with Crohn's Disease

Perianal fistula in patients with Crohn’s disease is an extremely challenging condition. The disease tends to reoccur, and with current treatment options, a large number of patients are left with active ailment and experience major morbidity. In recent years, hopeful results regarding local use of mesenchymal stem cells (MSCs) in perianal Crohn’s disease have been published. Although to this day there are no clear guidelines determining optimal dosage, injections frequency and culture conditions, their efficiency has proven to be much higher than conventionally used methods. According to studies, they can effectively induce as well as maintain fistula closure. This approach also avoids common side effects related to conventional surgical treatment.

Therapeutic and protective potential of mesenchymal stem cells, pharmaceutical agents and current vaccines against covid-19

It has been almost 18 months since the first outbreak of COVID-19 disease was reported in Wuhan, China. This unexpected devastating phenomenon, raised a great deal of concerns and anxiety among people around the world and imposed a huge economic burden on the nations' health care systems. Accordingly, clinical scientists, pharmacologists and physicians worldwide felt an urgent demand for a safe, effective therapeutic agent, treatment strategy or vaccine in order to prevent or cure the recently-emerged disease. Initially, due to lack of specific pharmacological agents and approved vaccines to combat the COVID-19, the disease control in the confirmed cases was limited to supportive care. Accordingly, repositioning or repurposing current drugs and examining their possible therapeutic efficacy received a great deal of attention. Despite revealing promising results in some clinical trials, the overall results are conflicting. For this reason, there is an urgent to seek and investigate other potential therapeutics. Mesenchymal stem cells (MSC) representing immunomodulatory and regenerative capacity to treat both curable and intractable diseases, have been investigated in COVID-19 clinical trials carried out in different parts of the world. Nevertheless, up to now, none of MSC-based approaches has been approved in controlling COVID-19 infection. Thanks to the fact that the final solution for defeating the pandemic is developing a safe, effective vaccine, enormous efforts and clinical research have been carried out. In this review, we will concisely discuss the safety and efficacy of the most relevant pharmacological agents, MSC-based approaches and candidate vaccines for treating and preventing COVID-19 infection.

Allogeneic expanded adipose-derived mesenchymal stem cell therapy for perianal fistulas in Crohn's disease: A case series

AIM

Even with optimal medical and surgical therapy, perianal fistulas in patients with Crohn's disease (CD) have low closure rates. As a new therapeutic option, administration of local mesenchymal stem cells (MSCs) has proved to be an innovative option after failure of treatment with immunosuppressive or immunomodulatory agents. The aim of this work is to share our first experience with MSC administration and demonstrate its efficacy, safety and feasibility outside a clinical trial.

METHOD

A total of 11 CD patients with complex perianal fistulas with nonactive or mildly active luminal disease were treated with local injection of 120 million allogeneic adipose-derived stem cells at a tertiary hospital between February 2019 and June 2020.

RESULTS

The mean age of the 11 patients was 38.3 years, 72.7% were men and 27.2% were smokers. The mean duration of fistula manifestation was 7.8 years and, except for one patient (therapy with tacrolimus), all other patients had been treated with an antitumour necrosis factor agent without fistula healing in the last 6 months. After a mean follow-up time of 41.5 weeks, 72.7% (8/11) of patients had complete closure of their fistula and three patients failed MSC treatment. Complete fistula healing could be observed 4-6 weeks postoperatively in half of the patients, while 36.5% (4/11) of patients developed a perianal abscess which had to be drained. One patient experienced cytomegalovirus viraemia 2 weeks after MSC administration and one patient developed a testicular carcinoma 16 weeks after treatment.

CONCLUSION

This case series demonstrates that the efficacy and safety of darvadstrocel in the ADMIRE trial can be replicated outside a clinical trial. This new modality in the treatment of complex perianal fistulas appears to be a promising therapeutic option for a challenging patient population.

Herb-partitioned moxibustion alleviates colonic inflammation in Crohn's disease rats by inhibiting hyperactivation of the NLRP3 inflammasome via regulation of the P2X7R-Pannexin-1 signaling pathway

Crohn's disease is a chronic inflammatory bowel disease and the NLRP3 inflammasome plays an important role in Crohn's disease. Previous studies have shown that Herb-partitioned moxibustion treating (at Qihai (CV 6) and Tianshu (ST 25)) prevented the excessive activation of the NLRP3 inflammasome and repaired damaged colonic mucosa in Crohn's disease. However, the mechanism by which Herb-partitioned moxibustion (at CV 6 and ST 25) regulates NLRP3 remains unclear. In this study, we treated Crohn's disease rats with herb-partitioned moxibustion (at CV 6 and ST 25) to investigate the mechanism by which Herb-partitioned moxibustion regulates the colonic NLRP3 inflammasome by observing colon length, the colon macroscopic damage indexes, and the expression of ATP, P2X7R, Pannexin-1, NF-κBp65, NLRP3, ASC, caspase-1, IL-1β and IL-18 in the colon in Crohn's disease. Here, this study shows that herb-partitioned moxibustion (at CV 6 and ST 25) can reduce colon macroscopic damage indexes and colon histopathological scores, alleviate colon shortening and block the abnormal activation of the NLRP3 inflammasome by inhibiting the ATP content and the expression of P2X7R, Pannexin-1 and NF-κBp65, thereby reducing the release of the downstream inflammatory cytokine IL-1β and ultimately suppressing colonic inflammation in Crohn's disease rats. This study for the first time identifies the mechanism by which herb-partitioned moxibustion (at CV 6 and ST 25) may inhibit the abnormal activation of the NLRP3 inflammasome by inhibiting the P2X7R-Pannexin-1 signaling pathway in Crohn's disease rats.

Mesenchymal stromal cell therapeutic potency is dependent upon viability, route of delivery, and immune match

Culture-adapted bone marrow mesenchymal stromal cells (MSCs) deploy paracrine anti-inflammatory and tissue regenerative functionalities that can be harnessed as a living cell pharmaceutical product. Independent of clinical indication, a near majority of human clinical trials administer MSC IV, often with an allogeneic MSC cell product immediately after thawing from cryostorage. Despite hundreds of studies in a wide assortment of inflammatory, degenerative, and acute tissue injury syndromes, human clinical outcomes often fail to mirror promising rigorously conducted preclinical animal studies. Using a mouse model of toxic colitis, we demonstrate that replication fit MSCs harvested in log phase of growth have substantial impact on colitis clinical and pathologic endpoints when delivered subcutaneously or intraperitoneally, whereas the maximum tolerated IV bolus dosing failed to do so. We also demonstrate that heat-inactivated MSCs lose all therapeutic utility and the observation is mirrored by use of viable MSC administered immediately postthaw from cryostorage. Using luciferase transgenic MSC as donor cells, we demonstrate that transient in vivo engraftment is severely compromised when MSCs are dead or thawed and further demonstrate that MSC redosing is feasible in relapsing colitis, but only syngeneic MSCs lead to sustained improvement of clinical endpoints. These data support the notion that pharmaceutical potency of MSC requires viability and functional fitness. Reciprocally, IV administration of thawed MSC products may be biased against positive clinical outcomes for treatment of colitis and that extravascular administration of syngeneic, fit MSCs allows for effect in a recurrent therapy model.

Mesenchymal stem cell immunomodulation: In pursuit of controlling COVID-19 related cytokine storm

The coronavirus disease 2019 (COVID-19) pandemic has grown to be a global public health crisis with no safe and effective treatments available yet. Recent findings suggest that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the coronavirus pathogen that causes COVID-19, could elicit a cytokine storm that drives edema, dysfunction of the airway exchange, and acute respiratory distress syndrome in the lung, followed by acute cardiac injury and thromboembolic events leading to multiorgan failure and death. Mesenchymal stem cells (MSCs), owing to their powerful immunomodulatory abilities, have the potential to attenuate the cytokine storm and have therefore been proposed as a potential therapeutic approach for which several clinical trials are underway. Given that intravenous infusion of MSCs results in a significant trapping in the lung, MSC therapy could directly mitigate inflammation, protect alveolar epithelial cells, and reverse lung dysfunction by normalizing the pulmonary microenvironment and preventing pulmonary fibrosis. In this review, we present an overview and perspectives of the SARS-CoV-2 induced inflammatory dysfunction and the potential of MSC immunomodulation for the prevention and treatment of COVID-19 related pulmonary disease.

Perianal fistulodesis – A pilot study of a novel minimally invasive surgical and medical approach for closure of perianal fistulae

BACKGROUND

Perianal fistulae strongly impact on quality of life of affected patients.

AIM

To challenge and novel minimally invasive treatment options are needed.

METHODS

Patients with Crohn’s disease (CD) in remission and patients without inflammatory bowel disease (non-IBD patients) were treated with fistulodesis, a method including curettage of fistula tract, flushing with acetylcysteine and doxycycline, Z-suture of the inner fistula opening, fibrin glue instillation, and Z-suture of the outer fistula opening followed by post-operative antibiotic prophylaxis with ciprofloxacin and metronidazole for two weeks. Patients with a maximum of 2 fistula openings and no clinical or endosonographic signs of a complicated fistula were included. The primary end point was fistula healing, defined as macroscopic and clinical fistula closure and lack of patient reported fistula symptoms at 24 wk.

RESULTS

Fistulodesis was performed in 17 non-IBD and 3 CD patients, with a total of 22 fistulae. After 24 wk, all fistulae were healed in 4 non-IBD and 2 CD patients (overall 30%) and fistula remained closed until the end of follow-up at 10-25 mo. In a secondary per-fistula analysis, 7 out of 22 fistulae (32%) were closed. Perianal disease activity index (PDAI) improved in patients with fistula healing. Low PDAI was associated with favorable outcome (P = 0.0013). No serious adverse events were observed.

CONCLUSION

Fistulodesis is feasible and safe for perianal fistula closure. Overall success rates is at 30% comparable to other similar techniques. A trend for better outcomes in patients with low PDAI needs to be confirmed.

Developing cell therapies as drug products

In the last 20 years, the global regulatory frameworks for drug assessment have been managing the challenges posed by using cellular products as new therapeutic tools. Currently, they are defined as "Advanced Therapy Medicinal Products", comprising a large group of cellular types that either alone or in combination with gene and tissue engineering technology. They have the potential to change the natural course of still lethal or highly debilitating diseases, including cancers, opportunistic infections and chronic inflammatory conditions. Globally, more than 50 cell-based products have obtained market authorization. This overview describes the advantages and unsolved challenges on developing cells as innovative therapeutic vehicles. The main cell therapy players and the legal framework are discussed, starting from chimeric antigen receptor T-cells for leukaemia and solid tumours, dealing then with lymphocytes as potent anti-microbiological tools and then focusing on mesenchymal stem/stromal cells whose role covers regenerative medicine, immunology and anti-tumour therapy.

Systematic Review of Stem-Cell-Based Therapy of Burn Wounds: Lessons Learned from Animal and Clinical Studies

Treatment of severe burn wounds presents a daunting medical challenge, and novel approaches promoting healing and reducing scarring are highly desirable. The application of mesenchymal stem/stromal cells (MSCs) has been suggested as a novel treatment. In this paper, we present systematic reviews of pre-clinical and clinical studies of MSC therapy for second- or third-degree thermal burn wounds. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, the PubMed and Embase databases were searched, and interventional studies of MSC therapy using rodent models (21 studies) or human burn patients (three studies) were included in the pre-clinical and clinical reviews, respectively, where both overall outcome and wound-healing-phase-specific methodologies and effects were assessed. The pre-clinical studies demonstrated a promising effect of the application of MSCs on several wound healing phases. The clinical studies also suggested that the MSC treatment was beneficial, particularly in the remodeling phase. However, the limited number of studies, their lack of homogeneity in study design, relatively high risk of bias, lack of reporting on mode of action (MOA), and discontinuity of evidence restrict the strength of these findings. This comprehensive review presents an overview of available methodologies to assess the MOA of MSC treatment for distinct wound healing phases. Furthermore, it includes a set of recommendations for the design of high-quality clinical studies that can determine the efficacy of MSCs as a therapy for burn wounds.

Management of patients with complex perianal fistulas in Crohn's disease: Optimal patient flow in the Italian clinical reality

Perianal fistulizing Crohn's disease (PFCD) is a common, disabling and aggressive phenotype that negatively impacts on the quality of life of affected patients. Its successful treatment is still a struggle for both physicians and patients. Significant advances in the management of this condition have occurred in the last two decades holding promise for a better future. This culminated into the concept of a collaborative multidisciplinary approach using the latest medical therapies combined with modern surgical and endoscopic techniques. Despite this, PFCD management and treatment have not been standardized yet. Thus the gastroenterologist and surgeon have to be familiar with several approaches and/or techniques. The positioning of each therapeutic option will certainly evolve with new data, but for the time being it should be driven by patient's characteristics, physician's preference and/or experience, costs and availability in local practice. Additionally, patient's perception of benefits and risks of treatment may differ from those of physicians and recognition of this difference is a starting point for difficult clinical decision-making. In this paper, a multidisciplinary group of Italian IBD experts explore and discuss current medical and surgical therapeutic options, highlighting areas of unmet needs in PFCD, with particular focus on the optimal patient flow within the Italian clinical reality.

A novel rat model of inflammatory bowel disease developed using a device created with a 3D printer

Objective

Inflammatory bowel disease (IBD) is an intractable condition. Existing models of experimental IBD are limited by their inability to create consistent ulcers between animals. The aim of this study was to develop a novel model of experimental colitis with ulcers of reproducible size.

Design

We used a 3D printer to fabricate a novel device containing a small window (10 × 10 mm) that could be inserted rectally to facilitate the creation of a localized ulcer in the rat intestinal mucosa. The mucosa within the window of the device was exposed to 2,4,6-trinitrobenzene sulfonic acid (TNBS) to generate ulceration. We evaluated the effects of conventional drug therapies (mesalazine and prednisolone) and local transplantation of allogeneic adipose-derived mesenchymal stem cells (ASCs) on ulcer size (measured from photographic images using image analysis software) and degree of inflammation (assessed histologically).

Results

The novel method produced localized, circular or elliptical ulcers that were highly reproducible in terms of size and depth. The pathological characteristics of the lesions were similar to those reported previously for conventional models of TNBS-induced colitis that show greater variation in ulcer size. Ulcer area was significantly reduced by the administration of mesalazine or prednisolone as an enema or localized injection of ASCs.

Conclusion

The new model of TNBS-induced colitis, made with the aid of a device fabricated by 3D printing, generated ulcers that were reproducible in size. We anticipate that our new model of colitis will provide more reliable measures of treatment effects and prove useful in future studies of IBD therapies.

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Adipose-derived stem cells (ASCs) are being explored as a new treatment for IBD because they can downregulate inflammation and improve tissue repair.

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A new model of TNBS-induced colitis was developed using a custom-designed device fabricated by a 3D printer.

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The novel model of colitis generated ulcers that were highly reproducible in size.

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The size of the ulcer was reduced by mesalazine or prednisolone (administered as an enema) or by localized injection of ASCs.

Treatment of complex recurrent fistula-in-ano by surgery combined to autologous bone marrow-derived mesenchymal stroma cells and platelet-rich plasma injection

PURPOSE

We report a case of successful management of complex recurrent cryptoglandular fistula-in-ano by surgery combined with autologous bone marrow-derived mesenchymal stroma cells (MSCs) and platelet-rich plasma (PRP) injection.

METHODS

Clinical, radiological, and surgical data of the patient were reviewed, as well as the current literature on complex fistula-in-ano.

RESULTS

A 37-year-old man with a recurrent cryptoglandular perianal fistula was addressed to our department. Inflammatory bowel disease was excluded by clinical history, endoscopy, and blood tests. Physical examination and MRI showed an anterior external orifice on the midline, 5 cm from the anal verge, with an internal orifice on the same line. Surgery combined to injection of MSC-PRP solution was successfully performed. MSC-PRP solution was prepared while the patient was under general anesthesia: bone marrow MSCs were obtained by centrifugation of a tibial puncture specimen and PRP from a peripheral whole blood sample of the patient. There were no adverse events post-operatively. Clinical and MRI examination 4 months after treatment confirmed the absence of perianal fistula. More than 2 years after surgery, there has been no recurrence.

CONCLUSIONS

Treatment of complex recurrent cryptoglandular fistula-in-ano by surgery combined to autologous bone marrow-derived MSCs and PRP injection seems safe in selected patients, allowing long-term healing. This procedure seems promising but further evaluation by clinical trials is warranted.