Treatment of Crohn's-Related Rectovaginal Fistula With Allogeneic Expanded-Adipose Derived Stem Cells: A Phase I-IIa Clinical Trial

TRANSPLANTATION OF ADIPOSE-DERIVED MESENCHYMAL STEM CELLS IN REFRACTORY CROHN'S DISEASE: SYSTEMATIC REVIEW

Background:

Crohn’s disease is a pathological condition that has different options of treatment, but there are patients who need other therapeutic approach, such as the use of adipose-derived mesenchymal stem cells.

Aim:

Systematic literature review to determine the different ways of adipose-derived mesenchymal stem cells administration in humans with luminal refractory and perianal fistulizing Crohn’s disease.

Methods:

It was conducted a search for articles (from 2008 to 2018) on PubMed and ScienceDirect databases using the keywords Crohn’s disease, fistulizing Crohn’s disease, luminal Crohn’s disease and transplantation of mesenchymal stem cells or mesenchymal stem cells or stromal cells. Thirteen publications were selected for analysis.

Results:

Only one study referred to the luminal Crohn´s disease. The number of cells administered was variable, occurring mainly through subcutaneous adipose tissue by liposuction. It could be highlighted the autologous transplant with exclusive infusion of mesenchymal stem cells. The procedures involved in pre-transplant were mainly curettage, setons placement and stitching with absorbable suture, and conducting tests and drug treatment for luminal Crohn´s disease. During transplant, the injection of mesenchymal stem cells across the fistula path during the transplant was mainly on the intestinal tract wall.

Conclusion:

Although the use of mesenchymal stem cells is promising, the transplant on the luminal region should be more investigated. The injection of mesenchymal stem cells, exclusively, is more explored when compared to treatment with other products. The preparation of the fistulizing tract and the location of cell transplantation involve standardized health care in most studies.

Mesenchymal stromal cell therapy in intestinal diseases

PURPOSE OF REVIEW

The advent of cell therapies, mainly based on the use of mesenchymal stromal cells (MSCs), represents a great step forward in the treatment of immune-mediated conditions. Here, we focus on those intestinal disorders wherein MSCs have been applied for immunotherapeutic purposes and whose results are available.

RECENT FINDINGS

By virtue of their ability to favour both tissue regeneration and immune tolerance, together with a substantial lack of immunogenicity, MSCs have gained huge attention in the last decade. Following abundant positive experimental data, a sizable number of clinical trials using MSCs as a new treatment in chronic inflammatory intestinal diseases were carried out with promising results and several are still ongoing. The main indication was refractory Crohn's disease wherein both feasibility and safety clearly emerged when treating the luminal phenotype with intravenous infusion/s, albeit no definitive conclusion on efficacy may be drawn. By contrast, the availability of robust demonstration also on the efficacy when treating the fistulizing phenotype through local injection/s of MSCs has led to approval of the marketing of an industrial preparation (darvadstrocel).

SUMMARY

Successful clinical implementation of this attractive option is hampered by a number of obstacles arising from methodology and regulation issues, which require the institution of interdisciplinary task forces before this cell therapy becomes a bedside reality.

Treatment Strategies in Crohn's-Associated Rectovaginal Fistula

Rectovaginal fistula (RVF) is a rare, but dreaded complication of Crohn's disease (CD) that is exceedingly difficult to manage. Treatment algorithms range from observation and medical therapy to local surgical repair and proctectomy. The multitude of surgical options and lack of consensus between experts speak to the complexity and shortcomings encountered to correct this disease process surgically. The key to successful management of these fistulae therefore rests on a multidisciplinary approach between the patient, gastroenterologists, and surgeons, with open communication about expectations and goals of care. In this article, we review the management of CD-associated RVF with an emphasis on surgical technique.

The Role of Monocytes and Macrophages in Autoimmune Diseases: A Comprehensive Review

Monocytes (Mo) and macrophages (Mϕ) are key components of the innate immune system and are involved in regulation of the initiation, development, and resolution of many inflammatory disorders. In addition, these cells also play important immunoregulatory and tissue-repairing roles to decrease immune reactions and promote tissue regeneration. Several lines of evidence have suggested a causal link between the presence or activation of these cells and the development of autoimmune diseases. In addition, Mo or Mϕ infiltration in diseased tissues is a hallmark of several autoimmune diseases. However, the detailed contributions of these cells, whether they actually initiate disease or perpetuate disease progression, and whether their phenotype and functional alteration are merely epiphenomena are still unclear in many autoimmune diseases. Additionally, little is known about their heterogeneous populations in different autoimmune diseases. Elucidating the relevance of Mo and Mϕ in autoimmune diseases and the associated mechanisms could lead to the identification of more effective therapeutic strategies in the future.

Regenerative Capacity of Adipose Derived Stem Cells (ADSCs), Comparison with Mesenchymal Stem Cells (MSCs)

Adipose tissue is now on the top one of stem cell sources regarding its accessibility, abundance, and less painful collection procedure when compared to other sources. The adipose derived stem cells (ADSCs) that it contains can be maintained and expanded in culture for long periods of time without losing their differentiation capacity, leading to large cell quantities being increasingly used in cell therapy purposes. Many reports showed that ADSCs-based cell therapy products demonstrated optimal efficacy and efficiency in some clinical indications for both autologous and allogeneic purposes, hence becoming considered as potential tools for replacing, repairing, and regenerating dead or damaged cells. In this review, we analyzed the therapeutic advancement of ADSCs in comparison to bone marrow (BM) and umbilical cord (UC)-mesenchymal stem cells (MSCs) and designed the specific requirements to their best clinical practices and safety. Our analysis was focused on the ADSCs, rather than the whole stromal vascular fraction (SVF) cell populations, to facilitate characterization that is related to their source of origins. Clinical outcomes improvement suggested that these cells hold great promise in stem cell-based therapies in neurodegenerative, cardiovascular, and auto-immunes diseases.

Regenerative Capacity of Adipose Derived Stem Cells (ADSCs), Comparison with Mesenchymal Stem Cells (MSCs)

Adipose tissue is now on the top one of stem cell sources regarding its accessibility, abundance, and less painful collection procedure when compared to other sources. The adipose derived stem cells (ADSCs) that it contains can be maintained and expanded in culture for long periods of time without losing their differentiation capacity, leading to large cell quantities being increasingly used in cell therapy purposes. Many reports showed that ADSCs-based cell therapy products demonstrated optimal efficacy and efficiency in some clinical indications for both autologous and allogeneic purposes, hence becoming considered as potential tools for replacing, repairing, and regenerating dead or damaged cells. In this review, we analyzed the therapeutic advancement of ADSCs in comparison to bone marrow (BM) and umbilical cord (UC)-mesenchymal stem cells (MSCs) and designed the specific requirements to their best clinical practices and safety. Our analysis was focused on the ADSCs, rather than the whole stromal vascular fraction (SVF) cell populations, to facilitate characterization that is related to their source of origins. Clinical outcomes improvement suggested that these cells hold great promise in stem cell-based therapies in neurodegenerative, cardiovascular, and auto-immunes diseases.

The clinical efficacy of stem cell therapy for complex perianal fistulas: a meta-analysis

BACKGROUND

Treatment of complex anal fistulas remains difficult. However, treatment with stem cells has had an encouraging success rate when applied to complex perianal fistulas. We systematically reviewed the current evidence through meta-analysis.

METHODS

We performed an electronic literature search on PubMed, Embase, and the Cochrane Library and identified studies (published between January 1946 and August 2017) that used stem cells to treat patients with complex perianal fistula. Each paper was evaluated for treatment success rate, target patients, types of stem cells used, number of cells used, and criteria for complete healing. Potential publication bias was assessed via visual inspection of a funnel plot and Orwin's fail-safe N. Out of 171 papers, 16 were included in the meta-analysis.

RESULTS

The overall healing rate of stem cell injection therapy for patients with complex perianal fistulas was 62.8% (95% CI 53.5-71.2, I² = 54.05%), whereas those for patients with Crohn's perianal fistulas alone and complex anal fistulas not associated with Crohn's disease were 64.1% and 61.5% (p = 0.840), respectively. Healing rates for autologous and allogenic stem cell treatment were 69.4% and 50.7% (p = 0.020), respectively. Four comparative studies out of 16 studies were analyzed separately. Stem cell therapy increased the healing rate compared to the control groups (OR 0.379, 95% CI 0.152-0.947).

CONCLUSIONS

Stem cell therapy is a good treatment option for complex perianal fistulas, which cannot be healed by conventional operative procedures. However, further research for additional supportive evidence, such as a large-scale randomized controlled trial, is required.

Delivery of oncolytic vaccinia virus by matched allogeneic stem cells overcomes critical innate and adaptive immune barriers

Background

Previous studies have identified IFNγ as an important early barrier to oncolytic viruses including vaccinia. The existing innate and adaptive immune barriers restricting oncolytic virotherapy, however, can be overcome using autologous or allogeneic mesenchymal stem cells as carrier cells with unique immunosuppressive properties.

Methods

To test the ability of mesenchymal stem cells to overcome innate and adaptive immune barriers and to successfully deliver oncolytic vaccinia virus to tumor cells, we performed flow cytometry and virus plaque assay analysis of ex vivo co-cultures of stem cells infected with vaccinia virus in the presence of peripheral blood mononuclear cells from healthy donors. Comparative analysis was performed to establish statistically significant correlations and to evaluate the effect of stem cells on the activity of key immune cell populations.

Results

Here, we demonstrate that adipose-derived stem cells (ADSCs) have the potential to eradicate resistant tumor cells through a combination of potent virus amplification and sensitization of the tumor cells to virus infection. Moreover, the ADSCs demonstrate ability to function as a virus-amplifying Trojan horse in the presence of both autologous and allogeneic human PBMCs, which can be linked to the intrinsic immunosuppressive properties of stem cells and their unique potential to overcome innate and adaptive immune barriers. The clinical application of ready-to-use ex vivo expanded allogeneic stem cell lines, however, appears significantly restricted by patient-specific allogeneic differences associated with the induction of potent anti-stem cell cytotoxic and IFNγ responses. These allogeneic responses originate from both innate (NK)- and adaptive (T)- immune cells and might compromise therapeutic efficacy through direct elimination of the stem cells or the induction of an anti-viral state, which can block the potential of the Trojan horse to amplify and deliver vaccinia virus to the tumor.

Conclusions

Overall, our findings and data indicate the feasibility to establish simple and informative assays that capture critically important patient-specific differences in the immune responses to the virus and stem cells, which allows for proper patient-stem cell matching and enables the effective use of off-the-shelf allogeneic cell-based delivery platforms, thus providing a more practical and commercially viable alternative to the autologous stem cell approach.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1829-z) contains supplementary material, which is available to authorized users.

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

Perianal fistulas in Crohn's disease (CD) represent a highly debilitating and difficult‐to‐treat condition. Given emerging supportive evidence, we conducted a systematic review and meta‐analysis of all trials/observational studies to establish the safety and efficacy of local injections of mesenchymal stem cells (MSCs). The PRISMA‐P statement was applied for planning and reporting, and MEDLINE, EMBASE, Web of Science, Cochrane, CINAHL, ClinicalTrials.gov database, and ECCO 2017 proceedings were searched for published observational studies and one‐arm and randomized clinical trials (RCTs). Safety was assessed in terms of acute local/systemic events, long‐term events, and relatedness with MSC treatment. Efficacy was evaluated in terms of external and/or radiological closure of fistula tracks. After a review of 211 citations, 23 studies, including 696 participants, were evaluated. Four were RCTs with a total of 483 patients. Overall, fistula closure occurred in 80% of MSC‐treated patients. In RCTs, this rate was 64% in the MSC arm and 37% in the control arm (relative risk (RR) = 1.54). Radiological response occurred in 83% of MSC‐treated patients. Treatment‐related adverse events occurred in 1% of MSC‐treated patients, with severe treatment‐related adverse events reaching 0% over a median follow‐up of 6 months. In RCTs, treatment‐related adverse events occurred in 13% in the MSC arm and 24% in the control arm (RR = 0.65). The relapse rate was 0. These results suggest that a local MSC injection is safe and efficacious. Further clinical trials with standardized end‐points are required to ensure the timely implementation of this new therapy in the management of perianal CD.

Considerations for high-yield, high-throughput cell enrichment: fluorescence versus magnetic sorting

Efficient sorting methods are required for the isolation of cellular subpopulations in basic science and translational applications. Despite this, throughputs, yields, viabilities, and processing times of common sorting methods like fluorescence-activated cell sorting (FACS) and magnetic-activated cell sorting (MACS) are underreported. In the current study, we set out to quantify the ability of these sorting methods to separate defined mixtures of alkaline phosphatase liver/bone/kidney (ALPL)-expressing and non-expressing cell types. Results showed that initial MACS runs performed using manufacturer’s recommended antibody and microbead concentrations produced inaccurate ALPL+ vs. ALPL− cell splits compared to FACS when ALPL+ cells were present in larger proportions (>~25%). Accuracy at all proportions could be achieved by using substantially higher concentrations of labeling reagents. Importantly, MACS sorts resulted in only 7–9% cell loss compared to ~70% cell loss for FACS. Additionally, MACS processing was 4–6 times faster than FACS for single, low proportion samples but took similar time for single, high-proportion samples. When processing multiple samples, MACS was always faster overall due to its ability to run samples in parallel. Average cell viability for all groups remained high (>83%), regardless of sorting method. Despite requiring substantial optimization, the ability of MACS to isolate increased cell numbers in less time than FACS may prove valuable in both basic science and translational, cell-based applications.

The Association of Coloproctology of Great Britain and Ireland consensus guidelines in surgery for inflammatory bowel disease

AIM

There is a requirement of an expansive and up to date review of surgical management of inflammatory bowel disease (IBD) that can dovetail with the medical guidelines produced by the British Society of Gastroenterology.

METHODS

Surgeons who are members of the ACPGBI with a recognised interest in IBD were invited to contribute various sections of the guidelines. They were directed to produce a procedure based document using literature searches that were systematic, comprehensible, transparent and reproducible. Levels of evidence were graded. An editorial board was convened to ensure consistency of style, presentation and quality. Each author was asked to provide a set of recommendations which were evidence based and unambiguous. These recommendations were submitted to the whole guideline group and scored. They were then refined and submitted to a second vote. Only those that achieved >80% consensus at level 5 (strongly agree) or level 4 (agree) after 2 votes were included in the guidelines.

RESULTS

All aspects of surgical care for IBD have been included along with 157 recommendations for management.

CONCLUSION

These guidelines provide an up to date and evidence based summary of the current surgical knowledge in the management of IBD and will serve as a useful practical text for clinicians performing this type of surgery.

Stem cells for luminal, fistulizing, and perianal inflammatory bowel disease: a comprehensive updated review of the literature

Much research has been performed over the last decade on stem cell therapy as treatment for patients with inflammatory bowel disease. Hematopoietic and mesenchymal stem cells, both allogeneic (from someone else) and autologous (from own patient), have been studied with safe and efficacious results in the majority of patients treated for luminal, perianal, and/or fistulizing disease. Here in this review, we highlight all human trials that have been conducted utilizing stem cell therapy treatment in patients with inflammatory bowel disease.

Objective demonstration of improvement of neurogenic bowel dysfunction in a case of spinal cord injury following stem cell therapy

Constipation in spinal cord injury patients is a frequent complication that leads to a reduction of quality of life, extensive psychological and economic strain on patients and healthcare systems. We report a 58-year-old man with an incomplete SCI secondary to L1 vertebral fracture, presented gait disorder with neurogenic bowel and bladder dysfunction. He received 300 million autologous mesenchymal stromal cells (MSC) in the subarachnoid space by lumbar puncture. After the third administration of MSC the patient had an important improvement in almost every functional scale of spinal cord injury, especially in the Krogh's Neurogenic Bowel Dysfunction scale. Our present observation supports recent clinical findings about the benefit of autologous stem cell therapy for the improvement of bowel dysfunction in patients suffering spinal cord injury.

Human Wharton's jelly mesenchymal stem cells protect axotomized rat retinal ganglion cells via secretion of anti-inflammatory and neurotrophic factors

Mesenchymal stem cell (MSC) transplantation is emerging as an ideal tool to restore the wounded central nervous system (CNS). MSCs isolated from extra-embryonic tissues have some advantages compared to MSCs derived from adult ones, such as an improved proliferative capacity, life span, differentiation potential and immunomodulatory properties. In addition, they are more immunoprivileged, reducing the probability of being rejected by the recipient. Umbilical cords (UCs) are a good source of MSCs because they are abundant, safe, non-invasively harvested after birth and, importantly, they are not encumbered with ethical problems. Here we show that the intravitreal transplant of Wharton´s jelly mesenchymal stem cells isolated from three different human UCs (hWJMSCs) delays axotomy-induced retinal ganglion cell (RGC) loss. In vivo, hWJMSCs secrete anti-inflammatory molecules and trophic factors, the latter alone may account for the elicited neuroprotection. Interestingly, this expression profile differs between naive and injured retinas, suggesting that the environment in which the hWJMSCs are modulates their secretome. Finally, even though the transplant itself is not toxic for RGCs, it is not innocuous as it triggers a transient but massive infiltration of Iba1⁺cells from the choroid to the retina that alters the retinal structure.

One more chance of fistula healing in inflammatory bowel disease: Stem cell therapy

Patients with fistulizing inflammatory bowel disease are traditionally difficult to treat. This patient population often experiences delayed or insufficient healing of fistulas using current standard regimens including antibiotics, immunomodulators, anti-tumor necrosis factor-αdrug, placement of setons, and surgical repair. Several studies over the last ten to fifteen years have been conducted using stem cell therapies with promising results in this patient population. These studies show stem cell therapy in fistulizing disease to be successful in healing between 60%-88% compared to currently 50% with infliximab. Moreover, remission was seen 24 wk to 52 wk in these studies. Further research with a multi-approach treatment using medications, stem cell therapy, and surgical interventions will likely be the future of this innovative treatment approach.

Standardization of mesenchymal stromal cell therapy for perianal fistulizing Crohn's disease

BACKGROUND

Local administration of mesenchymal stromal cells (MSCs) into the fistula tract seems to improve patient outcome in perianal fistulas due to Crohn's disease (CD). In this paper we propose a standardized and validated protocol for the local administration of MSCs for CD perianal fistulas to be able to reliably assess efficacy.

MATERIALS AND METHODS

A working group consisting of gastroenterologists and surgeons with expertise in the treatment of perianal CD developed a consensus perianal fistula treatment protocol for local MSC treatment of perianal fistulizing CD. The treatment protocol was validated during a trial of allogeneic bone marrow-derived MSCs for the treatment of refractory perianal Crohn's fistulas.

RESULTS

Localization and classification of perianal fistulas with MRI and rectoscopy is of crucial importance prior to surgical intervention with local therapy administration. Examination under anesthesia is necessary to incise and drain abscesses when present. Optimization of medical treatment when active luminal CD is present, is the first step before embarking on surgery and local therapy administration. In addition, strictures preventing the surgeon from adequately performing the surgical procedure have to be endoscopically dilated. Curettage of the fistula tract has an important role as long-standing CD perianal fistulas close poorly without removal of their epithelial lining. To diminish bacterial contamination of the fistula, the internal opening has to be closed. The origin of the fistula is the internal opening, therefore, efficacy of MSCs is presumably the highest when they are injected into the tissue around the internal opening.

CONCLUSION

In this article, we propose a standardized method of local MSC administration for perianal fistulizing CD. The use of this standardized and validated protocol for the administration of local treatment of CD perianal fistulas will allow reliable comparison of the efficacy of local therapies in future.

Mesenchymal stromal cells in the treatment of perianal fistulas in Crohn's disease

Significant unmet needs remain in patients with Crohn's disease and perianal fistulas. Mesenchymal stromal cells have potent immunomodulatory actions. The Phase II studies reported efficacy of local injection of mesenchymal stromal cells to achieve closure of fistulas. A Phase III trial demonstrated that in patients with Crohn's disease and refractory complex perianal fistulas, a single injection of 120 × 106 cells was superior to local injection of placebo associated with the same surgical procedure, in obtaining closure of the fistula tracts together with absence of abscesses >2 cm, 24 weeks after the injection, a stringent combined primary end point. The benefit over placebo was sustained 52 weeks after the single injection. The therapy is safe with adverse events limited to local pain.

Mesenchymal stem cells and immune disorders: from basic science to clinical transition

As a promising candidate seed cell type in regenerative medicine, mesenchymal stem cells (MSCs) have attracted considerable attention. The unique capacity of MSCs to exert a regulatory effect on immunity in an autologous/allergenic manner makes them an attractive therapeutic cell type for immune disorders. In this review, we discussed the current knowledge of and advances in MSCs, including its basic biological properties, i.e., multilineage differentiation, secretome, and immunomodulation. Specifically, on the basis of our previous work, we proposed three new concepts of MSCs, i.e., "subtotipotent stem cell" hypothesis, MSC system, and "Yin and Yang" balance of MSC regulation, which may bring new insights into our understanding of MSCs. Furthermore, we analyzed data from the Clinical Trials database ( http://clinicaltrials.gov ) on registered clinical trials using MSCs to treat a variety of immune diseases, such as graft-versus-host disease, systemic lupus erythematosus, and multiple sclerosis. In addition, we highlighted MSC clinical trials in China and discussed the challenges and future directions in the field of MSC clinical application.

Stem cell therapy for faecal incontinence: Current state and future perspectives

Faecal continence is a complex function involving different organs and systems. Faecal incontinence is a common disorder with different pathogeneses, disabling consequences and high repercussions for quality of life. Current management modalities are not ideal, and the development of new treatments is needed. Since 2008, stem cell therapies have been validated, 36 publications have appeared (29 in preclinical models and seven in clinical settings), and six registered clinical trials are currently ongoing. Some publications have combined stem cells with bioengineering technologies. The aim of this review is to identify and summarise the existing published knowledge of stem cell utilization as a treatment for faecal incontinence. A narrative or descriptive review is presented. Preclinical studies have demonstrated that cellular therapy, mainly in the form of local injections of muscle-derived (muscle derived stem cells or myoblasts derived from them) or mesenchymal (bone-marrow- or adipose-derived) stem cells, is safe. Cellular therapy has also been shown to stimulate the repair of both acute and subacute anal sphincter injuries, and some encouraging functional results have been obtained. Stem cells combined with normal cells on bioengineered scaffolds have achieved the successful creation and implantation of intrinsically-innervated anal sphincter constructs. The clinical evidence, based on adipose-derived stem cells and myoblasts, is extremely limited yet has yielded some promising results, and appears to be safe. Further investigation in both animal models and clinical settings is necessary to drawing conclusions. Nevertheless, if the preliminary results are confirmed, stem cell therapy for faecal incontinence may well become a clinical reality in the near future.

Concise Review: Using Fat to Fight Disease: A Systematic Review of Nonhomologous Adipose-Derived Stromal/Stem Cell Therapies

The objective of this Review is to describe the safety and efficacy of adipose stem/stromal cells (ASC) and stromal vascular fraction (SVF) in treating common diseases and the next steps in research that must occur prior to clinical use. Pubmed, Ovid Medline, Embase, Web of Science, and the Cochrane Library were searched for articles about use of SVF or ASC for disease therapy published between 2012 and 2017. One meta-analysis, 2 randomized controlled trials, and 16 case series were included, representing 844 human patients. Sixty-nine studies were performed in preclinical models of disease. ASCs improved symptoms, fistula healing, remission, and recurrence rates in severe cases of inflammatory bowel disease. In osteoarthritis, ASC and SVF improved symptom-related, functional, radiographic, and histological scores. ASC and SVF were also shown to improve clinical outcomes in ischemic stroke, multiple sclerosis, myocardial ischemia, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, chronic liver failure, glioblastoma, acute kidney injury, and chronic skin wounds. These effects were primarily paracrine in nature and mediated through reduction of inflammation and promotion of tissue repair. In the majority of human studies, autologous ASC and SVF from liposuction procedures were used, minimizing the risk to recipients. Very few serious, treatment-related adverse events were reported. The main adverse event was postprocedural pain. SVF and ASC are promising therapies for a variety of human diseases, particularly for patients with severe cases refractory to current medical treatments. Further randomized controlled trials must be performed to elaborate potential safety and efficacy prior to clinical use. Stem Cells 2018;36:1311-1328.

A Cell-Based Approach to the Treatment of Inflammatory Bowel Disease-Entering an Era of Regenerative Medicine

Corticosteroids, and more recently biologics, have been the mainstay of therapy for patients with inflammatory bowel disease. Unfortunately, both are fraught with side effects and limited by lack of efficacy or loss of response. Many patients ultimately succumb to medically refractory disease and require an operation. As we enter an era of regenerative medicine, a new genre of cell-based therapeutics offers significant promise for both an improved safety profile and improved efficacy compared with conventional treatment approaches. The ability to restore and rebuild health with autologous products rather than react to disease with pharmaceuticals gives hope to those who treat inflammatory bowel disease. The rationale and ongoing trials in an emerging field of medicine-regenerative medicine-is herein discussed.

Micro-fragmented adipose tissue injection for the treatment of complex anal fistula: a pilot study accessing safety and feasibility

BACKGROUND

The aim of the present study was to evaluate the safety and efficacy of autologous, micro-fragmented and minimally manipulated adipose tissue injection associated closure of the internal opening in promoting healing of complex anal fistula.

METHODS

A pilot study was conducted on patients referred to our center with anal fistula, from April 2015-December 2016. Inclusion criteria were age over 16 years old and a diagnosis of complex anal fistula according to the American Gastroenterological Association classification The patients were divided into 2 groups; the "first time group" (Group I) in which micro-fragmented adipose tissue injection with closure of the internal opening was the first sphincter-saving procedure, and the "recurrent group" (Group II) consisting of patients who had failed prior sphincter-saving procedures. The procedure was carried out 4-6 weeks after seton placement. Follow-up visits were scheduled at 7 days, and 1, 3, 6 and 12 months after surgery. Fistula healing was defined as the closure of the internal and external openings without any discharge.

RESULTS

Out of 47 patients with complex transsphincteric anal fistula, 19 met the inclusion criteria and were selected to undergo the procedure. Twelve of these patients (Group I) had micro-fragmented adipose tissue injection as first-line treatment, and 7 (Group II) had failed previous sphincter-saving procedures. The mean operative time was 55 ± 6 min (range 50-70 min). The mean postoperative pain score measured with the visual analog pain scale was 2 ± 1.4 (range 0-4). No intraoperative difficulties related to the use of the kit were recorded. There were no cases of postoperative fever or abdominal sepsis related to the procedure and no post-treatment perianal bleeding or impaired anal continence. Only 3 cases of minor abdominal wall hematoma that did not require any treatment and 1 case of perianal abscess were observed. Patients were evaluated for a mean follow-up time of 9 ± 3.1 months (range 3-12 months). The overall healing rate was 73.7, 83.3% for Group I and 57.1% for Group II.

CONCLUSIONS

The injection of autologous, micro-fragmented and minimally manipulated adipose tissue associated with closure of the internal opening is a safe, feasible and reproducible procedure and may enhance complex anal fistula healing.

Proceedings of the signature series event of the international society for cellular therapy: "Advancements in cellular therapies and regenerative medicine in digestive diseases," London, United Kingdom, May 3, 2017

A summary of the First Signature Series Event, "Advancements in Cellular Therapies and Regenerative Medicine for Digestive Diseases," held on May 3, 2017, in London, United Kingdom, is presented. Twelve speakers from three continents covered major topics in the areas of cellular therapy and regenerative medicine applied to liver and gastrointestinal medicine as well as to diabetes mellitus. Highlights from their presentations, together with an overview of the global impact of digestive diseases and a proposal for a shared online collection and data-monitoring platform tool, are included in this proceedings. Although growing evidence demonstrate the feasibility and safety of exploiting cell-based technologies for the treatment of digestive diseases, regulatory and methodological obstacles will need to be overcome before the successful implementation in the clinic of these novel attractive therapeutic strategies.

Rat model of anal sphincter injury and two approaches for stem cell administration

AIM

To establish a rat model of anal sphincter injury and test different systems to provide stem cells to injured area.

METHODS

Adipose-derived stem cells (ASCs) were isolated from BDIX rats and were transfected with green fluorescent protein (GFP) for cell tracking. Biosutures (sutures covered with ASCs) were prepared with 1.5 x 10⁶ GFP-ASCs, and solutions of 10⁶ GFP-ASCs in normal saline were prepared for injection. Anorectal normal anatomy was studied on Wistar and BDIX female rats. Then, we designed an anal sphincter injury model consisting of a 1-cm extra-mucosal miotomy beginning at the anal verge in the anterior middle line. The sphincter lesion was confirmed with conventional histology (hematoxylin and eosin) and immunofluorescence with 4', 6-diamidino-2-phenylindole (commonly known as DAPI), GFP and α-actin. Functional effect was assessed with basal anal manometry, prior to and after injury. After sphincter damage, 36 BDIX rats were randomized to three groups for: (1) Cell injection without repair; (2) biosuture repair; and (3) conventional suture repair and cell injection. Functional and safety studies were conducted on all the animals. Rats were sacrificed after 1, 4 or 7 d. Then, histological and immunofluorescence studies were performed on the surgical area.

RESULTS

With the described protocol, biosutures had been covered with at least 820000-860000 ASCs, with 100% viability. Our studies demonstrated that some ASCs remained adhered after suture passage through the muscle. Morphological assessment showed that the rat anal anatomy is comparable with human anatomy; two sphincters are present, but the external sphincter is poorly developed. Anal sphincter pressure data showed spontaneous, consistent, rhythmic anal contractions, taking the form of “plateaus” with multiple twitches (peaks) in each pressure wave. These basal contractions were very heterogeneous; their frequency was 0.91-4.17 per min (mean 1.6980, SD 0.57698), their mean duration was 26.67 s and mean number of peaks was 12.53. Our morphological assessment revealed that with the aforementioned surgical procedure, both sphincters were completely sectioned. In manometry, the described activity disappeared and was replaced by a gentle oscillation of basal line, without a recognizable pattern. Surprisingly, these findings appeared irrespective of injury repair or not. ASCs survived in this potentially septic area for 7 d, at least. We were able to identify them in 84% of animals, mainly in the muscular section area or in the tissue between the muscular endings. ASCs formed a kind of “conglomerate” in rats treated with injections, while in the biosuture group, they wrapped the suture. ASCs were also able to migrate to the damaged zone. No relevant adverse events or mortality could be related to the stem cells in our study. We also did not find unexpected tissue growths.

CONCLUSION

The proposed procedure produces a consistent sphincter lesion. Biosutures and injections are suitable for cell delivery. ASCs survive and are completely safe in this clinical setting.

Hematopoietic and mesenchymal stem cells: a promising new therapy for spondyloarthritis?

In the last years, a considerable progress has been made in the treatment of spondyloarthritides. Nonetheless, there remain a considerable number of patients who are unresponsive to all current therapies. Since the late 1990s, numerous trials have investigated the use of stem cell transplantation as a new approach for the treatment of autoimmune disease, particularly with hematopoietic stem cell transplantation. More recently, the research has focused on mesenchymal stem cell application due to their low immunogenicity and immunomodulatory properties. In this article, we summarize available data on hematopoietic stem cell and mesenchymal stem cell use for the treatment of spondyloarthritides and discuss the data gaps and possible research agenda in this area.

Stem Cell Therapy in Refractory Perineal Crohn's Disease: Long-term Follow-up

AIM

To describe the long-term outcomes of adipose-mesenchymal stem cells, platelet-rich plasma, and endorectal advancement flaps in patients with Perineal Crohn's Disease.

METHOD

This was a single-center, prospective, observational pilot study performed between March 2013 and December 2016. The study included adult patients diagnosed with Perianal Crohn's Disease (with complex perianal fistulas) refractory to previous surgical and/or biological treatment. Patients underwent surgical treatment in two stages. Stage 1: Fistula mapping, drainage, seton placement and lipoaspiration to obtain adipose-mesenchymal stem cells were performed. Stage 2: The setons were removed, and the fistula tract was debrided. A small endorectal advancement flap was created, with closure of the previous internal fistula opening. Then, 100-120 million adipose-mesenchymal stem cells mixed with platelet-rich plasma were injected into the internal fistula opening and fistula tract.

RESULTS

The study included nine patients (seven females), with a median age of 36 years (r = 23-57). Eleven fistula tracks were treated, of which, two were pouch-vaginal fistulas. The median follow-up period was 31 months (r=21-37). At the end of the follow-up period, 10/11 (91%) fistulas were completely healed and 1/11 (9%) was partially healed. At the end of this period, there was no evidence of fistula relapse or adverse reactions in any patients. The Perianal Disease Activity Index and Inflammatory Bowel Disease Questionnaire scores significantly improved after the procedure.

CONCLUSION

Combined therapy with adipose-mesenchymal stem cells, platelet-rich plasma and endorectal advancement flaps yielded good results in patients with refractory Perineal Crohn's Disease. This article is protected by copyright. All rights reserved.

Efficacy of autologous fat graft injection in the treatment of anovaginal fistulas

BACKGROUND

Injection of autologous fat is an established method within plastic surgery for soft tissue augmentation. The aim of the present study was to determine whether transperineal fat graft injection could promote healing of anovaginal fistulas.

METHODS

The procedures were performed at the University Hospital of North Norway, Tromsø, Norway, and at Aarhus University Hospital, Aarhus, Denmark, between May 2009 and September 2016. After abdominal liposuction, fat was injected around the fistula tract that was finally transected percutaneously with a sharp cannula and fat injected between the cut parts. The internal opening was closed with a suture. Patients had a minimum follow-up of 6 months after last fat graft injection.

RESULTS

Twenty-seven women underwent 48 procedures. The cause of fistula was obstetric (n = 9), abscess (n = 9), Crohn's disease (n = 7), radiation for anal cancer (n = 1) and endoscopic surgery after radiation for rectal cancer (n = 1). The mean amount of injected fat was 73 ml (SD ± 20 ml), and operating time was 63 min (SD ± 21 min). At median follow-up of 20 months (range 6-87 months) after the last injection, fistulas were healed in 21 women (77%), in 8 women after just one procedure. Healing was achieved in 6 of 7 women (86%) with Crohn's disease and in both women who had undergone radiation therapy. One woman developed an abscess and additional trans-sphincteric fistula 8 weeks after injection.

CONCLUSIONS

Fat graft injection for anovaginal fistulas is effective and safe.

Concise Review: A Safety Assessment of Adipose-Derived Cell Therapy in Clinical Trials: A Systematic Review of Reported Adverse Events

The popularity of adipose-derived cell therapy has increased over the last decade, and the number of studies published annually is growing. However, concerns regarding safety in the setting of previous malignancy or the use of allogeneic cells have been raised. We therefore aimed to systematically review all clinical studies using adipose-derived cell therapy to identify reported adverse events with a special focus on risk of thromboembolic, immunological, and oncological safety concerns. Our systematic search resulted in 70 included studies involving more than 1,400 patients that were treated with adipose-derived cell therapy. Safety assessment method was not described in 32 of the included studies. For studies involving systemic or cardiac administration, one case of pulmonary thromboembolism and cases of both myocardial and cerebral infarctions were described. In the setting of allogeneic cell therapy studies, where the production of specific antibodies toward donor cells was examined, it was noted that 19%-34% of patients develop antibodies, but the consequence of this is unknown. With regard to oncological safety, only one case of breast cancer recurrence was identified out of 121 patients. Adipose-derived cell therapy has so far shown a favorable safety profile, but safety assessment description has, in general, been of poor quality, and only adverse events that are looked for will be found. We encourage future studies to maintain a strong focus on the safety profile of cell therapy, so its safeness can be confirmed. Stem Cells Translational Medicine 2017;6:1786-1794.

Clinical trials using mesenchymal stem cells in liver diseases and inflammatory bowel diseases

Mesenchymal stem cell (MSC) therapies have been used in clinical trials in various fields. These cells are easily expanded, show low immunogenicity, can be acquired from medical waste, and have multiple functions, suggesting their potential applications in a variety of diseases, including liver disease and inflammatory bowel disease. MSCs help prepare the microenvironment, in response to inflammatory cytokines, by producing immunoregulatory factors that modulate the progression of inflammation by affecting dendritic cells, B cells, T cells, and macrophages. MSCs also produce a large amount of cytokines, chemokines, and growth factors, including exosomes that stimulate angiogenesis, prevent apoptosis, block oxidation reactions, promote remodeling of the extracellular matrix, and induce differentiation of tissue stem cells. According to ClinicalTrials.gov, more than 680 clinical trials using MSCs are registered for cell therapy of many fields including liver diseases (more than 40 trials) and inflammatory bowel diseases (more than 20 trials). In this report, we introduce background and clinical studies of MSCs in liver disease and inflammatory bowel diseases.

Current and emerging therapeutic targets for IBD

Various therapeutic advances have led to a paradigm shift in the clinical management of patients with IBD. The introduction of immunosuppressive (such as azathioprine) and biologic agents (such as TNF blockers) has markedly reduced the need to use corticosteroids for therapy. Furthermore, the α4β7 integrin blocker vedolizumab has been introduced for clinical IBD therapy. Moreover, various new inhibitors of cytokines (for example, IL-6-IL-6R and IL-12-IL-23 blockers or apremilast), modulators of cytokine signalling events (for example, JAK inhibitors or SMAD7 blocker), inhibitors of transcription factors (for example, GATA3 or RORγt) and new anti-adhesion and anti-T-cell-activation and migration strategies (for example, β7 integrin, sphingosine 1-phosphate receptors and MAdCAM1 inhibitors, regulatory T-cell therapy and stem cells) are currently being evaluated in controlled clinical trials. This Review aims to provide a comprehensive overview about current and future therapeutic approaches for IBD therapy. Furthermore, potential mechanisms of action of these therapeutic approaches and their implications for clinical therapy in IBD are discussed.

Management of rectovaginal fistulas and patient outcome

Rectovaginal fistulas are a relatively rare, but debilitating condition which pose a significant treatment challenge. Areas covered: In this manuscript we discuss the etiology, classification as well as the manifestations and evaluation of rectovaginal fistulas. We summarize the different surgical techniques and evaluate their success rates and perioperative considerations according to cited sources. Expert commentary: A deep understanding of the disease, treatment options, and familiarity with the different surgical treatment options available is mandatory for choosing the correct treatment. When the surgical treatment is tailored to the specific fistula and patient, many patients can eventually have successful resolution. This review will address the management and patient outcomes after treatment for rectovaginal fistulas.

Efficacy of Mesenchymal Stromal Cells for Fistula Treatment of Crohn's Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND AIM

The introduction of mesenchymal stromal cells (MSCs) has changed the management of Crohn's fistula, while it remains controversial. The aim of this study was to provide an overview of efficacy and optimum state of MSCs treatment on Crohn's fistula.

METHODS

Studies reporting MSCs treatment on Crohn's fistula were searched and included. A fixed-effects model was used to assess the efficacy of MSCs, and outcomes of healing and recurrence were used to evaluate the best states of MSCs intervention.

RESULTS

Fourteen articles were enrolled (n = 477). Pooled analysis showed MSCs had a significant efficacy compared to other treatments [risk difference: 0.21 (0.09, 0.32), P = 0.000]. Notably, after MSCs treatment, the group of Crohn's disease activity index (CDAI) baseline >150 group had a higher healing rate (HR) and a clinical response (a change in CDAI of >50 points) (79.17 ± 8.78 vs. 47.54 ± 15.90, P = 0.011) compared to CDAI baseline of <150. The duration time of CD and fistulas had a negative correlation with HR accompanied by MSC therapy (r = -0.900, -0.925). Then, a moderate dose MSCs (2-4 × 10⁷ cells/ml) had a higher HR (80.07%) and lower recurrence rate (RR 13.98%) compared to other dosages. Moreover, adipose-derived MSCs therapy had an advantage over bone marrow-derived MSCs in terms of low RR (7.4 ± 4.28 vs. 13.39 ± 0.89).

CONCLUSIONS

The evidence supported the effect of MSCs at a more appropriate time of Crohn's fistula. And CDAI baseline (the points >150) has been a candidate for evaluating effectiveness of MSCs application on Crohn's fistula.

Is Stem Cell Therapy Ready for Prime Time in Treatment of Inflammatory Bowel Diseases?

Autologous hematopoietic stem cell transplantation (HSCT) and mesenchymal stromal cell therapy have been proposed for patients with refractory Crohn's disease (CD) and fistulizing CD, respectively. Will these highly advanced techniques be available only for select patients, at specialized centers, or is further clinical development justified, with the aim of offering widespread, more definitive therapeutic options for often very difficult to treat disease? Patients with CD who are eligible for HSCT have typically been failed by most approved therapies, have undergone multiple surgeries, and have coped with years of disease activity and poor quality of life. The objective of HSCT is to immediately shut down the immune response and allow the transplanted stem cells to develop into self-tolerant lymphocytes. For patients with fistulizing CD, mesenchymal stromal cell therapy deposits MSCs locally, into fistulizing tracts, to down-regulate the local immune response and induce wound healing. Recent trials have produced promising results for HSCT and mesenchymal stromal cell therapy as alternatives to systemic therapies and antibiotics for patients with inflammatory bowel diseases, but are these immunotherapies ready for prime time?