A new method for treating fecal incontinence by implanting stem cells derived from human adipose tissue: preliminary findings of a randomized double-blind clinical trial

Regenerative Medicine in Urogynecology: Where We Are and Where We Want to Be

ABSTRACT

Pelvic floor disorders (PFDs) constitute a major public health issue given their negative effect on quality of life for millions of women worldwide and the associated economic burden. As the prevalence of PFDs continues to increase, novel therapeutic approaches for the effective treatment of these disorders are urgently needed. Regenerative medicine techniques, including cellular therapies, extracellular vesicles, secretomes, platelet-rich plasma, laser therapy, and bioinductive acellular biomaterial scaffolds, are emerging as viable clinical options to counteract urinary and fecal incontinence, as well as pelvic organ prolapse. This brief expert review explores the current state-of-science regarding application of these therapies for the treatment of PFDs. Although regenerative approaches have not been widely deployed in clinical care to date, these innovative techniques show a promising safety profile and potential to positively affect the quality of life of patients with PFDs. Furthermore, investigations focused on regeneration of the main constituents of the pelvic floor and lower urinary tract improve our understanding of the underlying pathophysiology of PFDs. Regenerative medicine techniques have a high potential not only to revolutionize treatment of PFDs but also to prevent these complex conditions.

Baiona's Consensus Statement for Fecal Incontinence. Spanish Association of Coloproctology

Faecal incontinence (FI) is a major health problem, both for individuals and for health systems. It is obvious that, for all these reasons, there is widespread concern for healing it or, at least, reducing as far as possible its numerous undesirable effects, in addition to the high costs it entails. There are different criteria for the diagnostic tests to be carried out and the same applies to the most appropriate treatment, among the numerous options that have proliferated in recent years, not always based on rigorous scientific evidence. For this reason, the Spanish Association of Coloproctology (AECP) proposed to draw up a consensus to serve as a guide for all health professionals interested in the problem, aware, however, that the therapeutic decision must be taken on an individual basis: patient characteristics/experience of the care team. For its development it was adopted the Nominal Group Technique methodology. The Levels of Evidence and Grades of Recommendation were established according to the criteria of the Oxford Centre for Evidence-Based Medicine. In addition, expert recommendations were added briefly to each of the items analysed.

The Mexican consensus on fecal incontinence

Fecal incontinence is the involuntary passage or the incapacity to control the release of fecal matter through the anus. It is a condition that significantly impairs quality of life in those that suffer from it, given that it affects body image, self-esteem, and interferes with everyday activities, in turn, favoring social isolation. There are no guidelines or consensus in Mexico on the topic, and so the Asociación Mexicana de Gastroenterología brought together a multidisciplinary group (gastroenterologists, neurogastroenterologists, and surgeons) to carry out the «Mexican consensus on fecal incontinence» and establish useful recommendations for the medical community. The present document presents the formulated recommendations in 35 statements. Fecal incontinence is known to be a frequent entity whose incidence increases as individuals age, but one that is under-recognized. The pathophysiology of incontinence is complex and multifactorial, and in most cases, there is more than one associated risk factor. Even though there is no diagnostic gold standard, the combination of tests that evaluate structure (endoanal ultrasound) and function (anorectal manometry) should be recommended in all cases. Treatment should also be multidisciplinary and general measures and drugs (lidamidine, loperamide) are recommended, as well as non-pharmacologic interventions, such as biofeedback therapy, in selected cases. Likewise, surgical treatment should be offered to selected patients and performed by experts.

The effect of Trolox on the rabbit anal sphincterotomy repair

INTRODUCTION

Fecal incontinence (FI) is caused by external anal sphincter injury. Vitamin E is a potential strategy for anal sphincter muscle repair via its antioxidant, anti-inflammatory, anti-fibrotic, and protective properties against myocyte loss. Thus, we aimed to evaluate the water-soluble form of vitamin E efficacy in repairing anal sphincter muscle defects in rabbits.

METHODS

Twenty-one male rabbits were equally assigned to the intact (without any intervention), control (sphincterotomy), and Trolox (sphincterotomy + Trolox administration) groups. Ninety days after sphincterotomy, the resting and squeeze pressures were evaluated by manometry, and the number of motor units in the sphincterotomy site was calculated by electromyography. Also, the amount of muscle and collagen in the injury site was investigated by Mallory's trichrome staining.

RESULTS

Ninety days after the intervention, the resting and squeeze pressures in the intact and Trolox groups were significantly higher than in the control group (P = 0.001). Moreover, the total collagen percentage of the sphincterotomy site was significantly lower in the Trolox group than in the control group (P = 0.002), and the total muscle percentage was significantly higher in the Trolox group compared to the control group (P = 0.001). Also, the motor unit number was higher in the Trolox group than in the control group (P = 0.001).

CONCLUSION

Trolox administration in the rabbit sphincterotomy model can decrease the amount of collagen and increase muscle, leading to improved anal sphincter electromyography and manometry results. Therefore, Trolox is a potential treatment strategy for FI.

Differentiation of Adipose-Derived Stem Cells into Smooth Muscle Cells in an Internal Anal Sphincter-Targeting Anal Incontinence Rat Model

OBJECTIVE

Studies on development of an anal incontinence (AI) model targeting smooth muscle cells (SMCs) of the internal anal sphincter (IAS) have not been reported. The differentiation of implanted human adipose-derived stem cells (hADScs) into SMCs in an IAS-targeting AI model has also not been demonstrated. We aimed to develop an IAS-targeting AI animal model and to determine the differentiation of hADScs into SMCs in an established model.

MATERIALS AND METHODS

The IAS-targeting AI model was developed by inducing cryoinjury at the inner side of the muscular layer via posterior intersphincteric dissection in Sprague-Dawley rats. Dil-stained hADScs were implanted at the IAS injury site. Multiple markers for SMCs were used to confirm molecular changes before and after cell implantation. Analyses were performed using H&E, immunofluorescence, Masson's trichrome staining, and quantitative RT-PCR.

RESULTS

Impaired smooth muscle layers accompanying other intact layers were identified in the cryoinjury group. Specific SMC markers, including SM22α, calponin, caldesmon, SMMHC, smoothelin, and SDF-1 were significantly decreased in the cryoinjured group compared with levels in the control group. However, CoL1A1 was increased significantly in the cryoinjured group. In the hADSc-treated group, higher levels of SMMHC, smoothelin, SM22α, and α-SMA were observed at two weeks after implantation than at one week after implantation. Cell tracking revealed that Dil-stained cells were located at the site of augmented SMCs.

CONCLUSIONS

This study first demonstrated that implanted hADSc restored impaired SMCs at the injury site, showing stem cell fate corresponding to the established IAS-specific AI model.

How Mechanical and Physicochemical Material Characteristics Influence Adipose-Derived Stem Cell Fate

Adipose-derived stem cells (ASCs) are a subpopulation of mesenchymal stem cells. Compared to bone marrow-derived stem cells, they can be harvested with minimal invasiveness. ASCs can be easily expanded and were shown to be able to differentiate into several clinically relevant cell types. Therefore, this cell type represents a promising component in various tissue engineering and medical approaches (e.g., cell therapy). In vivo cells are surrounded by the extracellular matrix (ECM) that provides a wide range of tissue-specific physical and chemical cues, such as stiffness, topography, and chemical composition. Cells can sense the characteristics of their ECM and respond to them in a specific cellular behavior (e.g., proliferation or differentiation). Thus, in vitro biomaterial properties represent an important tool to control ASCs behavior. In this review, we give an overview of the current research in the mechanosensing of ASCs and current studies investigating the impact of material stiffens, topography, and chemical modification on ASC behavior. Additionally, we outline the use of natural ECM as a biomaterial and its interaction with ASCs regarding cellular behavior.

Role of Autologous Fat Grafting in the Conservative Treatment of Fecal Incontinence in Children

Treatment of organic fecal incontinence in children, typical of anorectal malformations, is most often conservative; however, when necessary, it can be surgical. Autologous fat grafting, or lipofilling, can be used to improve fecal incontinence. We present our experience with the echo-assisted anal-lipofilling and its effects on fecal incontinence in children and on the quality of life of the entire family. Under general anesthesia, fat tissue was harvested according to the traditional technique, and processed in a closed system Lipogems^® set. Injection of the processed adipose tissue was guided by trans-anal ultrasound assistance. Ultrasound and manometry were also used for follow-up. From November 2018, we performed 12 anal-lipofilling procedures in six male patients (mean age 10.7 years). Five children had a stable improvement in bowel function with Krickenbeck's scale scores going from soiling grade 3 pre-treatment in 100% of children to grade 1 post-treatment in 75% of them. No major post-operative complications developed. An increase in thickness of the sphincteric apparatus was shown at ultrasound during follow-up. The quality of life of the entire family, evaluated with a questionnaire, improved after the surgical treatment of the children. Anal-lipofilling is a safe and effective procedure to reduce organic fecal incontinence thereby benefiting both the patients and their families.

Application of nanofat for treatment of traumatic faecal incontinence after sphincteroplasty - A pilot study

AIM

The aim of this study was to investigate whether the application of nanofat containing stem cells improves continence in women who had previously undergone anal sphincteroplasty with unsatisfactory long-term outcomes.

METHOD

This prospective pilot study included nine women with various degrees of anal incontinence who had previously undergone anal sphincteroplasty due to obstetric trauma. In all patients, the Wexner Incontinence Score (WS) and Faecal Incontinence Quality of Life Score (FIQLS), as well as anal manometry and endoanal ultrasound measurements, were performed before the procedure and during follow-up. In all patients, liposuction was performed and 50 ml of raw lipoaspirate was obtained and processed using a NanoFat Kit device. Approximately 20 ml of the mechanically emulsified and filtrated fat was obtained and the anal sphincter complex was infiltrated with it. Patient follow-up was conducted in person or via telephone 6 and 12 months after the procedure.

RESULTS

The squeeze pressure was significantly increased 6 months after the procedure (p = 0.01). The external anal sphincter measured at the 12 o'clock position was significantly thicker (p = 0.04). A significant decrease in the WS was observed both 6 and 12 months after the procedure compared with baseline values (p < 0.05 for both).

CONCLUSION

This study is the first to show that the application of nanofat as an injectable product improves continence in patients with unsatisfactory results after sphincteroplasty, suggesting it to be a promising and effective therapeutic tool. The procedure is safe and can be easily performed as an ambulatory procedure.

Local transplantation of syngeneic adipose stromal vascular fraction ameliorates damaged anal sphincter function in a rat model of vaginal distension

BACKGROUND

The adipose stromal vascular fraction contains abundant mesenchymal stem cells and is utilized for cell therapy of male stress urinary incontinence. The purpose of this paper was to explore the effect of local transplantation of the stromal vascular fraction on improvement of damaged anal sphincter function.

METHODS

A rat model of vaginal distension was used as a model of damaged anal sphincter function. The adipose stromal vascular fraction was separated from the inguinal fat of syngeneic green fluorescent protein transgenic rats and delivered into the internal anal sphincter of vaginal distension rats. The maximum resting pressure was evaluated during insertion and withdrawal of the catheter at 4 or 10 days after vaginal distension treatment to estimate anal sphincter function. Green fluorescent protein-transfected human-adipose-derived mesenchymal stem cells were transplanted into the internal anal sphincter of nude rats. Hematoxylin-eosin and Masson trichrome staining were performed to evaluate tissue damage and collagen synthesis. Transplanted cells were identified using a green fluorescent protein antibody and a human-specific antibody. Activation of the transplanted human-ADSC was evaluated by quantitative RT-PCR RESULTS: The mean maximum resting pressure (during catheter withdrawal) of vaginal distension rats was significantly lower than that of control rats, and stromal vascular fraction injection normalized it 4 days after treatment (control: 5.66 ± 0.98, vaginal distension: 4.04 ± 1.28, vaginal distension + stromal vascular fraction: 5.92 ± 1.28 [mmHg, control versus vaginal distension: P = .039; vaginal distension versus vaginal distension + stromal vascular fraction: P = .007]). Histological examination showed that vaginal distension disrupted the internal anal sphincter, and the transplanted syngeneic stromal vascular fraction survived for 10 days. Transplanted xenogeneic human-adipose-derived mesenchymal stem cells survived in the internal anal sphincter of nude rats for 4 and 10 days. Genes related to extracellular remodeling were up-regulated in the transplanted human-adipose-derived mesenchymal stem cells CONCLUSION: Syngeneic and heterotopic transplanted adipose-derived mesenchymal stem cells engrafted in the internal anal sphincter and ameliorated damaged anal sphincter function in a rat model of vaginal distension.

Guideline for the diagnosis and treatment of Faecal Incontinence-A UEG/ESCP/ESNM/ESPCG collaboration

INTRODUCTION

The goal of this project was to create an up-to-date joint European clinical practice guideline for the diagnosis and treatment of faecal incontinence (FI), using the best available evidence. These guidelines are intended to help guide all medical professionals treating adult patients with FI (e.g., general practitioners, surgeons, gastroenterologists, other healthcare workers) and any patients who are interested in information regarding the diagnosis and management of FI.

METHODS

These guidelines have been created in cooperation with members from the United European Gastroenterology (UEG), European Society of Coloproctology (ESCP), European Society of Neurogastroenterology and Motility (ESNM) and the European Society for Primary Care Gastroenterology (ESPCG). These members made up the guideline development group (GDG). Additionally, a patient advisory board (PAB) was created to reflect and comment on the draft guidelines from a patient perspective. Relevant review questions were established by the GDG along with a set of outcomes most important for decision making. A systematic literature search was performed using these review questions and outcomes as a framework. For each predefined review question, the study or studies with the highest level of study design were included. If evidence of a higher-level study design was available, no lower level of evidence was sought or included. Data from the studies were extracted by two reviewers for each predefined important outcome within each review question. Where possible, forest plots were created. After summarising the results for each review question, a systematic quality assessment using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach was performed. For each review question, we assessed the quality of evidence for every predetermined important outcome. After evidence review and quality assessment were completed, recommendations could be formulated. The wording used for each recommendation was dependent on the level of quality of evidence. Lower levels of evidence resulted in weaker recommendations and higher levels of evidence resulted in stronger recommendations. Recommendations were discussed within the GDG to reach consensus.

RESULTS

These guidelines contain 45 recommendations on the classification, diagnosis and management of FI in adult patients.

CONCLUSION

These multidisciplinary European guidelines provide an up-to-date comprehensive evidence-based framework with recommendations on the diagnosis and management of adult patients who suffer from FI.

Fecal Incontinence: Pathogenesis, Diagnosis, and Updated Treatment Strategies

Fecal incontinence (FI) is defined as the involuntary loss or passage of solid or liquid stool in patients. FI is a common and debilitating condition in men and women. The incidence increases with age and also often goes unreported to health care providers. It is crucial that providers ask at-risk patients about possible symptoms. Evaluation and management is tailored to specific symptoms and characteristics of the incontinence. If conservative methods fail to improve symptoms, then other surgical options are considered, such as sacral nerve stimulation and anal sphincter augmentation. This review provides an update on current and future therapies.

Stromal cell derived factor 1 plasmid to regenerate the anal sphincters

The aim of this study was to evaluate regeneration of a chronic large anal sphincter defect in a pig model after treatment with a plasmid encoding Stromal Cell Derived Factor-1(SDF-1).

METHODS

Under ethics approved protocol 19 age/weight matched Sinclair mini-pigs were subjected to excision of the posterior 50% of anal sphincter muscle and left to recover for 6 weeks. They were randomly allocated to receive either saline treatment (Saline 1 ml, n = 5), 1 injection of SDF-1 plasmid 2 mg/ml (1 SDF-1, n = 9) or 2 injections of SDF-1, 2 mg/ml each at 2 weeks intervals (2 SDF-1, n = 5). Euthanasia occurred 8 weeks after the last treatment. In vivo outcomes included anal resting pressures done under anesthesia pre-injury, pre-injection and before euthanasia (8 weeks after treatment). Anal ultrasound was done pre injury and pre-euthanasia. Tissues were saved for histology and analyzed quantitatively. Two way ANOVA followed by Holm-Sidak test and one way ANOVA followed by the Tukey test were used for data analysis, p < 0.05 was regarded as significant.

RESULTS

Posterior anal pressures at the 3 time points were not significantly different in the saline group. In contrast, post-treatment pressures in the 1 SDF-1 group pressures were significantly higher than both pre-injury (p = 0.001) and pre-treatment time points (p = 0.003). At the post-treatment time point, both 1 SDF-1 (p = 0.01) and 2 SDF-1 (p = 0.01) groups had significantly higher mean pressures compared to the saline group. Histology showed distortion of normal anatomy with patchy regeneration in the control group while muscle was more organized in both treatment groups.

CONCLUSIONS

Eight weeks after a single or two doses of SDF-1injected into a chronic anal sphincter injury improved resting anal pressures and regenerated muscle in the entire defect. SDF-1 plasmid is effective in treating chronic defects of the anal sphincter in a large animal and could be clinically translated.

Combined application of chondroitinase ABC and photobiomodulation with low-intensity laser on the anal sphincter repair in rabbit

Background

Photobiomodulation with low-intensity laser (LIL) and chondroitinase ABC (ChABC) can repair damaged muscle tissue, so the aim of this study was to investigate the effect of co-administration of these two factors on anal sphincter repair in rabbits.

Methods

Male rabbits were studied in 5 groups (n = 7): Control (intact), sphincterotomy, laser, ChABC and laser + ChABC. 90 days after intervention were evaluated resting and maximum squeeze pressures, number of motor units, collagen amount, markers of muscle regeneration and angiogenesis.

Results

Resting pressure in the Laser + ChABC group was higher than the sphincterotomy, laser and ChABC groups (p < 0.0001). Maximum squeeze pressure in the all study groups was higher than sphincterotomy group (p < 0.0001). In the laser + ChABC and ChABC groups, motor unit numbers were more than the sphincterotomy group (p < 0.0001). Collagen content was significantly decreased in the laser (p < 0.0001) and laser + ChABC groups. ACTA1 (p = 0.001) and MHC (p < 0.0001) gene expression in the Laser + ChABC group were more than the laser or ChABC alone. VEGFA (p = 0.009) and Ki67 mRNA expression (p = 0.01) in the Laser + ChABC group were more than the laser group, But vimentin mRNA expression (p < 0.0001) was less than the laser group.

Conclusion

Co-administration of ChABCs and photobiomodulation with LIL appears to improve the tissue structure and function of the anal sphincter in rabbits more than when used alone.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-02047-2.

Stem Cells in Clinical Trials for Pelvic Floor Disorders: a Systematic Literature Review

Pelvic floor disorders (PFDs) include a series of conditions that can be poorly tolerated, negatively affecting the quality of life. Current treatment options show unsatisfactory results and new ones are therefore needed. Stem cell (SC) therapy might be an alternative treatment strategy. This systematic review aims to define the state of art of SC therapy for PFDs in clinical trials, by systematically reviewing the available evidence. A systematic search strategy was conducted up to November 7, 2020, in PubMed, Scopus, Cochrane Library, and ISI Web of Science. Preclinical studies on animal models were not considered. Studies were included when the patients were affected by any PFDs and cells were isolated, cultured, and characterized as SC. The study protocol was registered in PROSPERO (CRD42020216551). A total of 11 prospective clinical studies were included in the final assessment, specifically 7 single-arm studies dealing with SC therapy for stress urinary incontinence and 4 with anal incontinence. Among the latter, there were two prospective, single-arm studies and two randomized controlled trials. No papers concerning the use of SC for prolapse repair were retrieved. Due to the great heterogeneity, data pooling was not possible. Stem cell injection resulted in a safe procedure, with few mild adverse side effects, mostly related to harvesting sites. However, a clear beneficial impact of SC treatment for the treatment of pelvic floor disorders could not be demonstrated. Further larger targeted studies with control arms are needed before any conclusions can be made.

Cell Therapy for Anal Sphincter Incontinence: Where Do We Stand?

Anal sphincter incontinence is a chronic disease, which dramatically impairs quality of life and induces high costs for the society. Surgery, considered as the best curative option, shows a disappointing success rate. Stem/progenitor cell therapy is pledging, for anal sphincter incontinence, a substitute to surgery with higher efficacy. However, the published literature is disparate. Our aim was to perform a review on the development of cell therapy for anal sphincter incontinence with critical analyses of its pitfalls. Animal models for anal sphincter incontinence were varied and tried to reproduce distinct clinical situations (acute injury or healed injury with or without surgical reconstruction) but were limited by anatomical considerations. Cell preparations used for treatment, originated, in order of frequency, from skeletal muscle, bone marrow or fat tissue. The characterization of these preparations was often incomplete and stemness not always addressed. Despite a lack of understanding of sphincter healing processes and the exact mechanism of action of cell preparations, this treatment was evaluated in 83 incontinent patients, reporting encouraging results. However, further development is necessary to establish the correct indications, to determine the most-suited cell type, to standardize the cell preparation method and to validate the route and number of cell delivery.

Bioengineering of the digestive tract: approaching the clinic

The field of regenerative medicine is developing technologies that, in the near future, will offer alternative approaches to either cure diseases affecting the gastrointestinal tract or slow their progression by leveraging the intrinsic ability of our tissues and organs to repair after damage. This article will succinctly illustrate the three technologies that are closer to clinical translation-namely, human intestinal organoids, sphincter bioengineering and decellularization, whereby the cellular compartment of a given segment of the digestive tract is removed to obtain a scaffold consisting of the extracellular matrix. The latter will be used as a template for the regeneration of a functional organ, whereby the newly generated cellular compartment will be obtained from the patient's own cells. Although clinical application of this technology is approaching, product development challenges are being tackled to warrant safety and efficacy.

Treatment of faecal incontinence with autologous expanded mesenchymal stem cells: results of a pilot study

AIM

Management of faecal incontinence (FI) remains challenging because no definitive optimal treatment for this condition has yet been determined. Regenerative medicine could be an attractive therapeutic alternative for treating FI. Here, we aimed to determine the safety and feasibility of autologous expanded mesenchymal stem cells derived from adipose tissue (AdMSCs) in the treatment of patients diagnosed with structural FI.

METHOD

This was a randomized, multicentre, triple-blinded, placebo-controlled pilot study conducted at four sites in Spain with 16 adults with FI and a sphincter defect. Autologous AdMSCs were obtained from patients from surgically excised adipose tissue. These patients were intralesionally infused with a single dose of 4 × 10⁷ AdMSCs or a placebo while under anaesthesia. We assessed the safety and feasibility of the treatment as the cumulative incidence of adverse events and the treatment efficacy using the Cleveland Clinic Faecal Incontinence Score, Faecal Incontinence Quality of Life score and Starck criteria to classify sphincter defects and anorectal physiology outcomes.

RESULTS

Adipose tissue extraction, cell isolation and intralesional infusion procedures were successful in all the patients. There was only one adverse event connected to adipose tissue extraction (a haematoma), and none was associated with the injection procedure. There were no significant differences in any of the assessed clinical, manometric or ultrasonographic parameters.

CONCLUSION

This study indicates that this infusion procedure in the anal sphincter is feasible and safe. However, it failed to demonstrate efficacy to treat patients with structural FI.

MSC-based therapy in female pelvic floor disorders

Mesenchymal stem cells (MSCs), also referred to as multipotent stromal cells or mesenchymal stromal cells, are present in multiple tissues and capable of differentiating into diverse cell lineages, holding a great promise in developing cell-based therapy for a wide range of conditions. Pelvic floor disorders (PFDs) is a common degenerative disease in women and may diminish a woman's quality of life at any age. Since the treatments for this disease are limited by the high rates of recurrence and surgical complications, seeking an ideal therapy in the restoration of pelvic floor function is an urgent issue at present. Herein, we summarize the cell sources of MSCs used for PFDs and discuss the potential mechanisms of MSCs in treating PFDs. Specifically, we also provide a comprehensive review of current preclinical and clinical trials dedicated to investigating MSC-based therapy for PFDs. The novel therapy has presented promising therapeutic effects which include relieving the symptoms of urinary or fecal incontinence, improving the biological properties of implanted meshes and promoting the injured tissue repair. Nevertheless, MSC-based therapies for PFDs are still experimental and the unstated issues on their safety and efficacy should be carefully addressed before their clinical applications.

In Vitro Cultures of Adipose-Derived Stem Cells: An Overview of Methods, Molecular Analyses, and Clinical Applications

Adipose-derived stem cells (ASCs) exhibiting mesenchymal stem cell (MSC) characteristics, have been extensively studied in recent years. Because they have been shown to differentiate into lineages such as osteogenic, chondrogenic, neurogenic or myogenic, the focus of most of the current research concerns either their potential to replace bone marrow as a readily available and abundant source of MSCs, or to employ them in regenerative and reconstructive medicine. There is close to consensus regarding the methodology used for ASC isolation and culture, whereas a number of molecular analyses implicates them in potential therapies of a number of pathologies. When it comes to clinical application, there is a range of examples of animal trials and clinical studies employing ASCs, further emphasizing the advancement of studies leading to their more widespread use. Nevertheless, in vitro studies will most likely continue to play a significant role in ASC studies, both providing the molecular knowledge of their ex vivo properties and possibly serving as an important step in purification and application of those cells in a clinical setting. Therefore, it is important to consider current methods of ASC isolation, culture, and processing. Furthermore, molecular analyses and cell surface properties of ASCs are essential for animal studies, clinical studies, and therapeutic applications of the MSC properties.

Effects of local injection and intravenous injection of allogeneic bone marrow mesenchymal stem cells on the structure and function of damaged anal sphincter in rats

Anal sphincter injury leads to damage to the anal structure and functions and has been identified as a major risk factor for fecal incontinence. Bone marrow mesenchymal stem cells (BMSCs) with capacities of multidifferentiation, paracrine, and low immunogenicity have been widely used in tissue repair and regeneration. The primary objective of this research was to compare the effects of different injection therapies of BMSCs on the injured anal sphincters. Ninety-six Sprague-Dawley female rats were randomly divided into four groups (n = 24 each): intravenous injection, local injection, sham operation, and normal control. For the first three groups, 25% removal of the anal sphincter complex was performed and 0.3-ml phosphate-buffered saline (PBS) (containing 10⁷ green fluorescent protein-labeled allogeneic BMSCs) was given accordingly to the treatment group 24 h after operation for 7 consecutive days. The sham operation group was injected with 0.3-ml PBS only. All cases had undergone evaluation in the 1st, 7th, 14th, and 28th postoperative days. The rats were sacrificed on the 28th postoperative day, and the anal sphincters were dissected to be analyzed by morphological examination. At 14 days postoperatively, local injection of BMSC significantly improved the peak contraction pressure, electromyography amplitude, and frequency of the injured anal sphincter compared with tail vein, but there was no significant difference in resting pressure until 28 days after sphincterectomy. Masson staining results confirmed that the local injection group had significantly more new muscles on the wound. BMSC could remarkably improve peak contraction pressure, electromyography amplitude, and muscle fibers on the wound, and local injection is superior to intravenous injection.

PRIMARY SPHINCTEROPLASTY COMPARING TWO DIFFERENT STITCHES IN ANAL FISTULA TREATMENT: EXPERIMENTAL STUDY IN RATS

Background:

Anal fistula is by definition the communication between the rectum or anal canal with the perineal region, which may be epithelialized and has cryptoglandular origin in 90% of cases. There are a large number of techniques for successfully treating trans-sphincteric fistulas of 20-50%, including primary sphincteroplasty, but it is not clear whether the material used would influence the outcome.

Aim:

To analyze the efficacy of polydioxanone and polypropylene wire in primary post-fistulotomy sphincteroplasty in the treatment of trans-sphincteric fistulas in rats.

Methods:

Thirty Wistar rats had transfixation of the anal sphincter with steel wire, which remained for 30 days for the development of the anal fistula. After this period, it was removed and four groups were formed: A (control) without treatment; B (fistulotomy) submitted to such procedure and curettage only; C (polidioxanone) in which sphincteroplasty was performed after fistulotomy with polydioxanone wire; D (polypropylene) submitted to the same treatment as group C, but with polypropylene wire. After 30 days, euthanasia and removal of the specimens were performed for qualitative histopathological analysis, measurement of the area between the muscular cables edges and evaluation of the degree of local fibrosis.

Results:

There was persistence of the anal fistula in all animals of group A. There were no significant differences between groups B, C and D regarding the distance of the muscular cables (p=0.078) and the degree of fibrosis caused by the different treatments (p=0.373).

Conclusions:

There was no difference between polydioxanone and polypropylene wires in post-fistulotomy primary sphincteroplasty, and this technique was not superior to simple fistulotomy in relation to the distance of the muscular cables nor did it present differences in relation to the degree of local fibrosis.

Combination of laser and human adipose-derived stem cells in repair of rabbit anal sphincter injury: a new therapeutic approach

Background

Anal sphincter injury leads to fecal incontinence. Based on the regenerative capability of laser and human adipose-derived stem cells (hADSCs), this study was designed to assess the effects of co-application of these therapies on anal sphincter recovery after injury.

Design

Male rabbits were assigned to equal groups (n = 7) including control, sphincterotomy, sphincterotomy treated with laser (660 nm, 90 s, immediately after sphincterotomy, daily, 14 days), hADSCs (2 × 10⁶ hADSCs injected into injured area of the sphincter immediately after sphincterotomy), and laser + hADSCs. Ninety days after sphincterotomy, manometry and electromyography were performed, sphincter collagen content was evaluated, and Ki67, myosin heavy chain (MHC), skeletal muscle alpha-actin (ACTA1), vascular endothelial growth factor A (VEGFA), and vimentin mRNA gene expression were assessed.

Results

The laser + hADSCs group had a higher resting pressure compared with the sphincterotomy (p < 0.0001), laser (p < 0.0001), and hADSCs (p = 0.04) groups. Maximum squeeze pressure was improved in all treated animals compared with the sphincterotomized animals (p < 0.0001), without a significant difference between treatments (p > 0.05). In the laser + hADSCs group, motor unit numbers were higher than those in the laser group (p < 0.0001) but did not differ from the hADSCs group (p = 0.075). Sphincterotomy increased collagen content, but the muscle content (p = 0.36) and collagen content (p = 0.37) were not significantly different between the laser + hADSCs and control groups. Laser + hADSCs increased ACTA1 (p = 0.001) and MHC (p < 0.0001) gene expression compared with laser or hADSCs alone and was associated with increased VEGFA (p = 0.009) and Ki67 mRNA expression (p = 0.01) and decreased vimentin mRNA expression (p < 0.0001) compared with laser.

Conclusion

The combination of laser and hADSCs appears more effective than either treatment alone for promoting myogenesis, angiogenesis, and functional recovery after anal sphincterotomy.

Posterior Tibial Nerve Stimulation in Fecal Incontinence: A Systematic Review and Meta-Analysis

Introduction:

The present systematic review and meta-analysis aims to investigate the role of Posterior Tibial Nerve Stimulation (PTNS) in the control of Fecal Incontinence (FI).

Methods:

Two independent reviewers extensively searched in the electronic databases of Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, CINAHL, and Scopus for the studies published until the end of 2016. Only randomized clinical trials were included. The studied outcomes included FI episodes, FI score, resting pressure, squeezing pressure, and maximum tolerable pressure. The data were reported as Standardized Mean Differences (SMD) with 95% confidence interval.

Results:

Five articles were included in the present study (249 patients under treatment with PTNS and 239 in the sham group). Analyses showed that PTNS led to a significant decrease in the number of FI episodes (SMD=−0.38; 95% CI: −0.67–0.10; P=0.009). Yet, it did not have an effect on FI score (SMD=0.13; 95% CI: −0.49–0.75; P=0.68), resting pressure (SMD=0.12; 95% CI: −0.14–0.37; P=0.67), squeezing pressure (SMD=−0.27; 95% CI: −1.03–0.50; P=0.50), and maximum tolerable pressure (SMD=−0.10; 95% CI: −0.40–0.24; P=0.52).

Conclusion:

Based on the results, it seems that the prescription of PTNS alone cannot significantly improve FI.

Cell therapy to improve regeneration of skeletal muscle injuries

Diseases that jeopardize the musculoskeletal system and cause chronic impairment are prevalent throughout the Western world. In Germany alone, ~1.8 million patients suffer from these diseases annually, and medical expenses have been reported to reach 34.2bn Euros. Although musculoskeletal disorders are seldom fatal, they compromise quality of life and diminish functional capacity. For example, musculoskeletal disorders incur an annual loss of over 0.8 million workforce years to the German economy. Among these diseases, traumatic skeletal muscle injuries are especially problematic because they can occur owing to a variety of causes and are very challenging to treat. In contrast to chronic muscle diseases such as dystrophy, sarcopenia, or cachexia, traumatic muscle injuries inflict damage to localized muscle groups. Although minor muscle trauma heals without severe consequences, no reliable clinical strategy exists to prevent excessive fibrosis or fatty degeneration, both of which occur after severe traumatic injury and contribute to muscle degeneration and dysfunction. Of the many proposed strategies, cell-based approaches have shown the most promising results in numerous pre-clinical studies and have demonstrated success in the handful of clinical trials performed so far. A number of myogenic and non-myogenic cell types benefit muscle healing, either by directly participating in new tissue formation or by stimulating the endogenous processes of muscle repair. These cell types operate via distinct modes of action, and they demonstrate varying levels of feasibility for muscle regeneration depending, to an extent, on the muscle injury model used. While in some models the injury naturally resolves over time, other models have been developed to recapitulate the peculiarities of real-life injuries and therefore mimic the structural and functional impairment observed in humans. Existing limitations of cell therapy approaches include issues related to autologous harvesting, expansion and sorting protocols, optimal dosage, and viability after transplantation. Several clinical trials have been performed to treat skeletal muscle injuries using myogenic progenitor cells or multipotent stromal cells, with promising outcomes. Recent improvements in our understanding of cell behaviour and the mechanistic basis for their modes of action have led to a new paradigm in cell therapies where physical, chemical, and signalling cues presented through biomaterials can instruct cells and enhance their regenerative capacity. Altogether, these studies and experiences provide a positive outlook on future opportunities towards innovative cell-based solutions for treating traumatic muscle injuries-a so far unmet clinical need.

A systematic review and network meta-analysis comparing treatments for faecal incontinence

BACKGROUND

Although numerous treatments exist for fecal incontinence (FI), no consensus exists on the best treatment strategy. The aim was to review the literature and to compare the clinical outcomes and effectiveness of treatments available for FI.

MATERIALS AND METHOD

A systematic literature review was performed, from inception to May 2018, of the following databases: MEDLINE, EMBASE, Science Citation Index Expanded, Cochrane Library. The search terms used were "faecal incontinence" and "treatment". Only randomized controlled trials (RCTs) comparing treatments for FI were considered. A Bayesian network meta-analysis was performed using the Markov chain Monte Carlo method.

RESULT

Forty-seven RCTs were included comparing 37 treatments and reporting on 3748 participants. No treatment ranked best or worst with high probability for any outcome of interest. No significant difference was identified between treatments for frequency of FI per week, or in changing the resting pressure, maximum resting pressure, squeeze pressure, and maximum squeeze pressure. Radiofrequency resulted in more adverse events compared to placebo. Sacral nerve stimulation (SNS) and zinc-aluminium improved the fecal incontinence quality of life questionnaire (FIQL) lifestyle, coping, and embarrassment domains compared to placebo. Transcutaneous posterior tibial nerve stimulation (TPTNS) improved the FIQL embarrassment domain compared to placebo. Autologous myoblasts and zinc-aluminium improved the FIQL depression domain compared to placebo. SNS, artificial bowel sphincter (ABS), and zinc-aluminium significantly improved incontinence scores compared to placebo. Injection of non-animal stabilized hyaluronic acid/dextranomer (NASHA/Dx) resulted in more patients with ≥50% reduction in FI episodes compared to placebo.

CONCLUSION

SNS, ABS, TPTNS, NASHA/Dx, zinc-aluminium, and autologous myoblasts resulted in isolated improvements in specific outcomes of interest. No difference was identified in incontinence episodes, no treatment ranked best persistently or persistently improved outcomes, and many included treatments did not significantly benefit patients compared to placebo. Large multicentre RCTs with long-term follow-up and standardized inclusion criteria and outcome measures are needed.

Biomimetic Scaffolds in Skeletal Muscle Regeneration

Skeletal muscle tissue has inherent capacity for regeneration in response to minor injuries. However, in the case of severe trauma, tumor ablations, or in congenital muscle defects, these myopathies can cause irreversible loss of muscle mass and function, a condition referred to as volumetric muscle loss (VML). The natural muscle repair mechanisms are overwhelmed, prompting the search for new muscle regenerative strategies, such as using biomaterials that can provide regenerative signals to either transplanted or host muscle cells. Recent studies involve the use of suitable biomaterials which may be utilized as a template to guide tissue reorganization and ultimately provide optimum micro-environmental conditions to cells. These strategies range from approaches that utilize biomaterials alone to those that combine materials with exogenous growth factors, and ex vivo cultured cells. A number of scaffold materials have been used in the development of grafts to treat VML. In this brief review, we outline the natural skeletal regeneration process, available treatments used in the clinic for muscle injury and promising tissue bioengineering and regenerative approaches for muscle loss treatment.

Regenerative medicine as a therapeutic option for fecal incontinence: a systematic review of preclinical and clinical studies

BACKGROUND

Fecal incontinence is the uncontrollable loss of stool and has a prevalence of around 7-15%. This condition has serious implications for patients' quality of life. Current treatment options show unsatisfactory results. A novel treatment option is therefore needed.

OBJECTIVE

This systematic review aims to perform a quality assessment and to give a critical overview of the current research available on regenerative medicine as a treatment for fecal incontinence.

STUDY DESIGN

A systematic search strategy was applied in PubMed, Cochrane Library, EMBASE, MEDLINE, Web of Science, and Cinahl from inception until March of 2018. Studies were found relevant when the animals or patients in the studied group had objectively determined or induced fecal incontinence, and the intervention must have used any kind of cells, stem cells, or biocompatible material, with or without the use of trophic factors. Studies were screened on title and consecutively on abstract for relevance by 2 independent investigators. The risk of bias of preclinical studies was assessed using the SYstematic Review Centre for Laboratory animal Experimentation risk of bias tool for animal studies, and for clinical studies the Cochrane risk of bias tool for randomized trials was used.

RESULTS

In all, 34 preclinical studies and 5 clinical studies were included. Animal species, type of anal sphincter injury, intervention, and outcome parameters were heterogenous. Therefore, a meta-analysis could not be performed. The overall risk of bias of the included studies was high.

CONCLUSION

The efficacy of regenerative medicine to treat fecal incontinence could not be determined due to the high risk of bias and heterogenicity of the available preclinical and clinical studies. The findings of this systematic review may result in improved study design of future studies, which could help the translation of regenerative medicine to the clinic as an alternative to current treatments for fecal incontinence.

A systematic review of the literature reporting on randomised controlled trials comparing treatments for faecal incontinence in adults

AIM

To perform a review of the literature reporting on randomised controlled trials (RCTs) comparing treatments for faecal incontinence (FI) in adults.

METHODS

A literature search of MEDLINE, Embase, Science Citation Index Expanded and Cochrane was performed in order to identify RCTs reporting on treatments for FI.

RESULTS

The review included 60 RCTs reporting on 4838 patients with a mean age ranging from 36.8 to 88 years. From the included RCTs, 32 did not identify a significant difference between the treatments compared. Contradictory results were identified in RCTs comparing percutaneous posterior tibial nerve stimulation and transcutaneous tibial nerve stimulation versus sham stimulation, biofeedback-pelvic floor muscle training (BF-PFMT) versus PFMT, and between bulking agents such as PTQ^TM versus Durasphere^®. In two separate RCTs, combination treatment of amplitude-modulated medium frequency stimulation and electromyography-biofeedback (EMG-BF), was noted to be superior to EMG-BF and low-frequency electrical stimulation alone. Combination of non-surgical treatments such as BF with sphincteroplasty significantly improved continence scores compared to sphincteroplasty alone. Surgical treatments were associated with higher rates of serious adverse events compared to non-surgical interventions.

CONCLUSIONS

The current evidence has not identified significant differences between treatments for FI, and where differences were identified, the results were contradictory between RCTs.

Isolation of internal and external sphincter progenitor cells from the human anal sphincter with or without radiotherapy

AIM

We aimed to isolate and propagate internal and external anal sphincter progenitor cells from the human anal sphincter, with or without radiotherapy, for tailored cell therapy of faecal incontinence.

METHODS

Sphincter progenitor cells were isolated from normal internal and external anal sphincters collected from 10 patients with rectal cancer who had undergone abdominoperineal resection with (n = 6) or without (n = 4) preoperative chemoradiotherapy. The isolated cells and differentiated muscle fibres were identified using immunofluorescence assay, western blotting and reverse transcription polymerase chain reaction (RT-PCR). The proliferation of progenitor cells with and without radiotherapy was compared by quantitative 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

The immunofluorescence assay before differentiation confirmed that the internal anal sphincter progenitor cells expressed CD34 and neural-glial antigen 2 (NG2), whereas the external anal sphincter progenitor cells expressed CD34 and PAX7. After differentiation, the internal anal sphincter progenitor cells expressed desmin, calponin and α-smooth muscle actin, whereas the external anal sphincter progenitor cells expressed desmin, myogenic factor 4 and myosin heavy chain. The differential expression profiles of both cell types were confirmed by western blotting and RT-PCR. MTT assays showed that the viability of internal and external anal sphincter progenitor cells was significantly lower in the radiotherapy group than that in the nonradiotherapy group.

CONCLUSIONS

This study describes the differential harvest internal and external sphincter muscle progenitor cells from human anal sphincters. We confirm that radiotherapy decreases the viability of internal and external anal sphincter progenitor cells.

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.

Functional and histologic effects after implanting pluripotent stem cells in a murine model with sphincterotomy

INTRODUCTION AND AIMS

Fecal incontinence is a disabling condition with devastating consequences for the patients. Medical and surgical options are not very satisfactory, reason by which regenerative medicine has been considered in this field. In the present research, we analyzed functional and histologic effects after implanting pluripotent stem cells (PSCs) in a murine model with sphincterotomy.

MATERIALS AND METHODS

Female Wistar rats were subjected to sphincterotomy and divided into three groups. Group 1 (control group) was treated with 300μL of balanced saline solution and group 2 (late treatment) and group 3 (early treatment) received 50,000 PSCs resuspended in 300μL of balanced saline solution. All animals were evaluated through high-resolution anorectal manometry 24hours before and after sphincterotomy and every month for three months. Finally, the rats were euthanized and histopathologic sections from the anal canal were obtained.

RESULTS

All groups showed a decrease in resting anal pressure and squeeze anal pressure 24hours after sphincterotomy. At the third month, higher anal pressures in the groups treated with PSCs were detected. Regarding the histologic effects, the microscopic architecture was restored and there was a significant decrease in the inflammatory response in the groups treated with PSCs.

CONCLUSION

PSCs implantation improves anal tone, as well as histologic structure, presenting better regenerative results when implanted as early treatment.

Comment on "A new method for treating fecal incontinence by implanting stem cells derived from human adipose tissue: preliminary findings of a randomized double-blind clinical trial"

In the study by Sarveazad et al. adipose tissue-derived stem cells were injected to reinforce anal sphincter repair. The authors came to the conclusion that injection of stem cells during repair surgery for fecal incontinence may cause replacement of fibrous tissue, which may be a key point in treatment of fecal incontinence. The authors emphasized in their “Discussion” section that the ability of stem cells to differentiate into muscle fibers, replacing the fibrous tissue at the site of repair, is their main action, which may not be accurate. We think that healing of repaired anal sphincter begins with granulation tissue formation, which then matures into fibrous tissue that becomes infiltrated by muscle fibers from the approximated cut ends of the sphincter, resulting in regain of sphincter muscle continuity. This is supported by many experimental studies that have evaluated local injection of stem cells during sphincteroplasty in rats and shown that the injected stem cells do not differentiate into muscle fibers but may induce healing by a strong fibrous tissue. Further studies are needed to determine the main mechanism of action of mesenchymal stems cells in augmenting anal sphincter repair.

Functional Outcome of Human Adipose Stem Cell Injections in Rat Anal Sphincter Acute Injury Model

Anal incontinence is a devastating condition that significantly reduces the quality of life. Our aim was to evaluate the effect of human adipose stem cell (hASC) injections in a rat model for anal sphincter injury, which is the main cause of anal incontinence in humans. Furthermore, we tested if the efficacy of hASCs could be improved by combining them with polyacrylamide hydrogel carrier, Bulkamid. Human ASCs derived from a female donor were culture expanded in DMEM/F12 supplemented with human platelet lysate. Female virgin Sprague‐Dawley rats were randomized into four groups (n = 14–15/group): hASCs in saline or Bulkamid (3 × 10⁵/60 μl) and saline or Bulkamid without cells. Anorectal manometry (ARM) was performed before anal sphincter injury, at two (n = 58) and at four weeks after (n = 33). Additionally, the anal sphincter tissue was examined by micro‐computed tomography (μCT) and the histological parameters were compared between the groups. The median resting and peak pressure during spontaneous contraction measured by ARM were significantly higher in hASC treatment groups compared with the control groups without hASCs. There was no statistical difference in functional results between the hASC‐carrier groups (saline vs. Bulkamid). No difference was detected in the sphincter muscle continuation between the groups in the histology and μCT analysis. More inflammation was discovered in the group receiving saline with hASC. The hASC injection therapy with both saline and Bulkamid is a promising nonsurgical treatment for acute anal sphincter injury. Traditional histology combined with the 3D μCT image data lends greater confidence in assessing muscle healing and continuity. Stem Cells Translational Medicine2018;7:295–304

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.

Stromal Cell-Derived Factor 1 Plasmid Regenerates Both Smooth and Skeletal Muscle After Anal Sphincter Injury in the Long Term

BACKGROUND

Regenerating muscle at a time remote from injury requires re-expression of cytokines to attract stem cells to start and sustain the process of repair.

OBJECTIVE

We aimed to evaluate the sustainability of muscle regeneration after treatment with a nonviral plasmid expressing stromal cell-derived factor 1.

DESIGN

This was a randomized study.

SETTINGS

The study was conducted with animals in a single research facility.

INTERVENTIONS

Fifty-six female age-/weight-matched Sprague-Dawley rats underwent excision of the ventral half of the anal sphincter complex. Three weeks later, rats were randomly allocated (n = 8) to one of the following groups: no treatment, 100 μg of plasmid encoding stromal cell-derived factor 1 injected locally, local injection of plasmid and 8 × 10 bone marrow-derived mesenchymal stem cells, and plasmid encoding stromal cell-derived factor 1 injected locally with injection of a gelatin scaffold mixed with bone marrow-derived mesenchymal stem cells.

MAIN OUTCOME MEASURES

Anal manometry, histology, immunohistochemistrym and morphometry were performed 8 weeks after treatment. Protein expression of cytokines CXCR4 and Myf5 was investigated 1 week after treatment (n = 6 per group). ANOVA was used, with p < 0.0083 indicating significant differences for anal manometry and p < 0.05 for all other statistical analysis.

RESULTS

Eight weeks after treatment, all of the groups receiving the plasmid had significantly higher anal pressures than controls and more organized muscle architecture in the region of the defect. Animals receiving plasmid alone had significantly greater muscle in the defect (p = 0.03) than either animals with injury alone (p = 0.02) or those receiving the plasmid, cells, and scaffold (p = 0.03). Both smooth and skeletal muscles were regenerated significantly more after plasmid treatment. There were no significant differences in the protein levels of CXCR4 or Myf5.

LIMITATIONS

The study was limited by its small sample size and because stromal cell-derived factor 1 was not blocked.

CONCLUSIONS

A plasmid expressing stromal cell-derived factor 1 may be sufficient to repair an injured anal sphincter even long after the injury and in the absence of mesenchymal stem cell or scaffold treatments. See Video Abstract at http://links.lww.com/DCR/A451.