Muscle Precursor Cells for the Restoration of Irreversibly Damaged Sphincter Function

Cell Therapy in the Treatment of Female Stress Urinary Incontinence: Current Status and Future Proposals

BACKGROUND

Stress urinary incontinence (SUI) is a common condition with a significant impact on the quality of life of female patients. The limitations of current treatment strategies have prompted the exploration of new effective and minimally invasive alternative approaches, including cell therapy.

METHODS

A literature search was conducted to update the current clinical status of stem cell therapy in the management of female stress urinary incontinence.

RESULTS

Over thirty clinical studies have been designed to assess the feasibility, safety and efficacy of cell therapy for female SUI. Despite differences in cell types and protocols, the overall treatment procedures were similar. Standard subjective and objective assessment tools, and follow-up periods ranged from 6 weeks to 6 years have been used. Cell injection has shown to be a safe therapy in the treatment of female SUI. However, the results from more recent randomized trials have shown less promising results than expected in restoring continence. Heterogeneous research methodologies using different cell types and doses make it difficult to draw conclusions about effectiveness. Several key points remain that need to be further explored in future clinical trials.

CONCLUSION

To advance in the development of cell therapy, it is essential to know the mechanisms involved to be able to direct it properly, its efficacy and the durability of the injected cells. Rigorous and homogenized preclinical and clinical studies that demonstrate its scope and improve its application are necessary for validation in the treatment of female SUI.

Transurethral injection of autologous muscle precursor cells for treatment of female stress urinary incontinence: a prospective phase I clinical trial

INTRODUCTION AND HYPOTHESIS

The purpose was to investigate the safety and feasibility of transurethral injections of autologous muscle precursor cells (MPCs) into the external urinary sphincter (EUS) to treat stress urinary incontinence (SUI) in female patients.

METHODS

Prospective and randomised phase I clinical trial. Standardised 1-h pad test, International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI-SF), urodynamic study, and MRI of the pelvis were performed at baseline and 6 months after treatment. MPCs gained through open muscle biopsy were transported to a GMP facility for processing and cell expansion. The final product was injected into the EUS via a transurethral ultrasound-guided route. Primary outcomes were defined as any adverse events (AEs) during follow-up. Secondary outcomes were functional, questionnaire, and radiological results.

RESULTS

Ten female patients with SUI grades I-II were included in the study and 9 received treatment. Out of 8 AEs, 3 (37.5%) were potentially related to treatment and treated conservatively: 1 urinary tract infection healed with antibiotics treatment, 1 dysuria and 1 discomfort at biopsy site. Functional urethral length under stress was 25 mm at baseline compared with 30 mm at 6 months' follow-up (p=0.009). ICIQ-UI-SF scores improved from 7 points at baseline to 4 points at follow-up (p=0.035). MRI of the pelvis revealed no evidence of tumour or necrosis, whereas the diameter of the EUS muscle increased from 1.8 mm at baseline to 1.9 mm at follow-up (p=0.009).

CONCLUSION

Transurethral injections of autologous MPCs into the EUS for treatment of SUI in female patients can be regarded as safe and feasible. Only a minimal number of expected and easily treatable AEs were documented.

Fibrotic remodeling and tissue regeneration mechanisms define the therapeutic potential of human muscular progenitors

Fibrosis is an intrinsic biological reaction toward the challenges of tissue injury that is implicated in the wound-healing process. Although it is useful to efficiently mitigate the damage, progression of fibrosis is responsible for the morbidity and mortality occurring in a variety of diseases. Because of lacking effective treatments, there is an emerging need for exploring antifibrotic strategies. Cell therapy based on stem/progenitor cells is regarded as a promising approach for treating fibrotic diseases. Appropriate selection of cellular sources is required for beneficial results. Muscle precursor cells (MPCs) are specialized progenitors harvested from skeletal muscle for conducting muscle regeneration. Whether they are also effective in regulating fibrosis has seldom been explored and merits further investigation. MPCs were successfully harvested from all human samples regardless of demographic backgrounds. The extracellular matrices remodeling was enhanced through the paracrine effects mediated by MPCs. The suppression effects on fibrosis were confirmed in vivo when MPCs were transplanted into the diseased animals with oral submucous fibrosis. The data shown here revealed the potential of MPCs to be employed to simultaneously regulate both processes of fibrosis and tissue regeneration, supporting them as the promising cell candidates for development of the cell therapy for antifibrosis and tissue regeneration.

Human primary muscle stem cells regenerate injured urethral sphincter in athymic rats

Background

The aim of the study was to demonstrate the efficacy of human muscle stem cells (MuSCs) isolated using innovative technology in restoring internal urinary sphincter function in a preclinical animal model.

Methods

Colonies of pure human MuSCs were obtained from muscle biopsy specimens. Athymic rats were subjected to internal urethral sphincter damage by electrocauterization. Five days after injury, 2 × 10⁵ muscle stem cells or medium as control were injected into the area of sphincter damage (n = 5 in each group). Peak bladder pressure and rise in pressure were chosen as outcome measures. To repeatedly obtain the necessary pressure values, telemetry sensors had been implanted into the rat bladders 10 days prior to injury.

Results

There was a highly significant improvement in the ability to build up peak pressure as well as a pressure rise in animals that had received muscle stem cells as compared to control (p = 0.007) 3 weeks after the cells had been injected. Only minimal histologic evidence of scarring was observed in treated rats.

Conclusion

Primary human muscle stem cells obtained using innovative technology functionally restore internal urethral sphincter function after injury. Translation into use in clinical settings is foreseeable.

The use of autologous skeletal muscle progenitor cells for adjunctive treatment of presumptive urethral sphincter mechanism incompetence in female dogs

BACKGROUND

Urethral sphincter mechanism incompetence (USMI) is a common problem in female dogs, but some dogs fail to achieve continence with standard treatment. Urethral submucosal injection of autologous skeletal muscle progenitor cells (skMPCs) previously has been shown to restore urethral function in a canine model of USMI.

HYPOTHESIS/OBJECTIVE

To determine if urethral submucosal injection of skMPC alters continence in dogs with USMI that had previously failed standard medical management. We hypothesized that the injections would lead to improved continence.

ANIMALS

Fifteen client-owned dogs with USMI that had failed standard medical management.

METHODS

Dogs were prospectively enrolled into a single-armed clinical trial. Once enrolled, a triceps muscle of each dog was biopsied; the tissue specimens were digested, cultured, and expanded to 100 million cells before injection into the urethral submucosa using a surgical approach. Continence was assessed at baseline and 3, 6, 12, and 24 months post-injection using continence scores and urethral pressure profilometry.

RESULTS

Median continence scores increased significantly from baseline at 3, 6, 12, and 24 months. Increases were seen in 14 of 15 dogs with 7, 6 or 1 dog achieving scores of 5, 4 or 3, respectively. Additional medication was required to achieve continence in all but 2 dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Urethral submucosal injection of skMPC can be used adjunctively to improve continence in dogs with difficult to manage USMI. The procedure is labor intensive but well tolerated; most dogs will require continued medication to remain continent.

Long-term effects of muscle-derived stem cell therapy on the regeneration of the urethra of female rats

INTRODUCTION AND HYPOTHESIS

The aim was to analyze the long-term effects of muscle-derived stem cells (MDSCs) therapy in traumatized urethras of female rats regarding messenger ribonucleic acid (mRNA) expression of collagens 1 and 3, Ngf and Ki67; and the mRNA and protein expression of Myh11 and Myh2.

METHODS

Muscle-derived stem cells were injected into the tail vein of rats 3 days after trauma by vaginal distention. Urethras were analyzed from 30 animals divided into three groups: control without injury or treatment, trauma (30 days post-injury), and MDSC (30 days post-injury who received MDSC therapy). Real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry were performed. The Kruskal-Wallis and ANOVA tests were used with p < 0.05 indicating significance.

RESULTS

We detected increased Myh11 and Myh2 mRNA expression in the trauma group compared with the control group (p = 0.03 and p = 0.04 respectively). Ki67 and Col1a1 genes were overexpressed in the MDSC group compared with both the trauma (p = 0.02 and p = 0.008 respectively) and the control group (p = 0.01 and p = 0.03 respectively). Col3a1 gene was upregulated in the MDSC compared with the control group (p = 0.03). Ngf mRNA level was lower in the MDSC group than in the trauma group (p = 0.002). Myh11, Myh2, and Desmin proteins were overexpressed in the MDSC compared with the trauma group (1.5-fold, p = 0.01; 1.5-fold, p = 0.04; 1.3-fold, p = 0.01 respectively).

CONCLUSIONS

Muscle-derived stem cell therapy may have had long-term structural and molecular effects on the injured urethra of female rats, particularly on markers of cell proliferation, neural growth factor, extracellular matrix, and muscle content. This study suggests that MDSC therapy acted mainly to produce urethral sphincter regeneration marked by increased immunohistochemical expression of the proteins desmin, smooth muscle Myh11, and skeletal muscle Myh2.

Replacing Needle Injection by a Novel Waterjet Technology Grants Improved Muscle Cell Delivery in Target Tissues

Current regimen to treat patients suffering from stress urinary incontinence often seems not to yield satisfactory improvement or may come with severe side effects. To overcome these hurdles, preclinical studies and clinical feasibility studies explored the potential of cell therapies successfully and raised high hopes for better outcome. However, other studies were rather disappointing. We therefore developed a novel cell injection technology to deliver viable cells in the urethral sphincter complex by waterjet instead of using injection needles. We hypothesized that the risk of tissue injury and loss of cells could be reduced by a needle-free injection technology. Muscle-derived cells were obtained from young male piglets and characterized. Upon expansion and fluorescent labeling, cells were injected into cadaveric tissue samples by either waterjet or injection needle. In other experiments, labeled cells were injected by waterjet in the urethra of living pigs and incubated for up to 7 days of follow-up. The analyses documented that the cells injected by waterjet in vitro were viable and proliferated well. Upon injection in live animals, cells appeared undamaged, showed defined cellular somata with distinct nuclei, and contained intact chromosomal DNA. Most importantly, by in vivo waterjet injections, a significantly wider cell distribution was observed when compared with needle injections (P < .05, n ≥ 12 samples). The success rates of waterjet cell application in living animals were significantly higher (≥95%, n = 24) when compared with needle injections, and the injection depth of cells in the urethra could be adapted to the need by adjusting waterjet pressures. We conclude that the novel waterjet technology injects viable muscle cells in tissues at distinct and predetermined depth depending on the injection pressure employed. After waterjet injection, loss of cells by full penetration or injury of the tissue targeted was reduced significantly in comparison with our previous studies employing needle injections.

Injection of Porcine Adipose Tissue-Derived Stromal Cells by a Novel Waterjet Technology

Previously, we developed a novel, needle-free waterjet (WJ) technology capable of injecting viable cells by visual guided cystoscopy in the urethral sphincter. In the present study, we aimed to investigate the effect of WJ technology on cell viability, surface markers, differentiation and attachment capabilities, and biomechanical features. Porcine adipose tissue-derived stromal cells (pADSCs) were isolated, expanded, and injected by WJ technology. Cell attachment assays were employed to investigate cell-matrix interactions. Cell surface molecules were analyzed by flow cytometry. Cells injected by Williams Needle (WN), normal cannula, or not injected cells served as controls. Biomechanical properties were assessed by atomic force microscopy (AFM). pADSCs injected by the WJ were viable (85.9%), proliferated well, and maintained their in vitro adipogenic and osteogenic differentiation capacities. The attachment of pADSCs was not affected by WJ injection and no major changes were noted for cell surface markers. AFM measurements yielded a significant reduction of cellular stiffness after WJ injections (p < 0.001). WJ cell delivery satisfies several key considerations required in a clinical context, including the fast, simple, and reproducible delivery of viable cells. However, the optimization of the WJ device may be necessary to further reduce the effects on the biomechanical properties of cells.

Treatment of Stress Urinary Incontinence with Muscle Stem Cells and Stem Cell Components: Chances, Challenges and Future Prospects

Urinary incontinence (UI) is a major problem in health care and more than 400 million people worldwide suffer from involuntary loss of urine. With an increase in the aging population, UI is likely to become even more prominent over the next decades and the economic burden is substantial. Among the different subtypes of UI, stress urinary incontinence (SUI) is the most prevalent and focus of this review. The main underlying causes for SUI are pregnancy and childbirth, accidents with direct trauma to the pelvis or medical treatments that affect the pelvic floor, such as surgery or irradiation. Conservative approaches for the treatment of SUI are pelvic physiotherapy, behavioral and lifestyle changes, and the use of pessaries. Current surgical treatment options include slings, colposuspensions, bulking agents and artificial urinary sphincters. These treatments have limitations with effectiveness and bear the risk of long-term side effects. Furthermore, surgical options do not treat the underlying pathophysiological causes of SUI. Thus, there is an urgent need for alternative treatments, which are effective, minimally invasive and have only a limited risk for adverse effects. Regenerative medicine is an emerging field, focusing on the repair, replacement or regeneration of human tissues and organs using precursor cells and their components. This article critically reviews recent advances in the therapeutic strategies for the management of SUI and outlines future possibilities and challenges.

Evaluation of Urinary Sphincter Function by Rapid Magnetic Resonance Diffusion Tensor Imaging

PURPOSE

This study aimed to assess the feasibility of a rapid diffusion tensor imaging (DTI) for evaluation of the female urinary sphincter function based on differentiation between rest and muscle contraction.

METHODS

Magnetic resonance imaging (MRI) of the lower pelvis was performed at 3 Tesla in 10 healthy female volunteers (21-36 years; body mass index, 20.8±3.6 kg/m2) between June and July 2019. High-resolution T1- and T2-weighted images were acquired for anatomical reference, and following DTI performed in 4 experiment phases: twice during rest (denoted rest-1, rest-2) and contraction (contraction-1, contraction-2). Manual segmentation of the urinary sphincter and the levator ani muscles were performed by 2 independent readers. Mean diffusivity (MD) and fractional anisotropy (FA) values derived from DTI volumes were compared in search for significant differences between the experiment phases. Interreader agreement was assessed by intraclass correlation coefficient (ICC).

RESULTS

Kruskal-Wallis test showed significant differences between MD values among all the experiment phases, by both independent readers (1st: X2 [3,76]=17.16, P<0.001 and 2nd: X2 [3,76]=15.88, P<0.01). Post hoc analysis revealed differences in MD values by both readers between: rest-1 vs. contraction-1 (least P<0.05), rest-1 vs. contraction-2 (P<0.01), rest-2 vs. contraction-1 (P<0.03), rest-2 vs. contraction-2 (P=0.02) with overall mean 'rest' to 'contraction' ΔMD=20.6%. No MD or FA differences were found between rest-1 vs. rest-2 and contraction-1 vs. contraction-2 among all the experiment phases, and interreader agreement was ICC=0.85 (MD) and ICC=0.79 (FA).

CONCLUSION

Rapid DTI might prospectively act as a supporting tool for the evaluation of female pelvic floor muscle function, and incontinence assessment.

Rapid and precise delivery of cells in the urethral sphincter complex by a novel needle-free waterjet technology

OBJECTIVES

To investigate the therapy of stress urinary incontinence in a preclinical setting cells were injected into the urethrae of minipigs; however, cells injected by William's needle were frequently misplaced or lost; thus, we investigated if needle-free cell injections using a novel waterjet technology facilitates precise injections in the urethral sphincter complex.

MATERIALS AND METHODS

Porcine adipose tissue-derived stromal cells (pADSCs) were isolated from boars, expanded, labelled, and injected in the sphincter of female pigs by waterjet employing two different protocols. After incubation for 15 min or 3 days, the urethrae of the pigs were examined. Injected cells were visualised by imaging and fluorescence microscopy of tissue sections. DNA of injected male cells was verified by polymerase chain reaction (PCR) of the sex-determining region (SRY) gene. Cell injections by William's needle served as controls.

RESULTS

The new waterjet technology delivered pADSCs faster and with better on-site precision than the needle injections. Bleeding during or after waterjet injection or other adverse effects, such as swelling or urinary retention, were not observed. Morphologically intact pADSCs were detected in the urethrae of all pigs treated by waterjet. SRY-PCR of chromosomal DNA and detection of recombinant green fluorescent protein verified the injection of viable cells. In contrast, three of four pigs injected by William's needle displayed no or misplaced cells.

CONCLUSION

Transurethral injection of viable pADSCs by waterjet is a simple, fast, precise, and yet gentle new technology. This is the first proof-of-principle concept study providing evidence that a waterjet injects intact cells exactly in the tissue targeted in a preclinical in vivo situation. To further explore the clinical potential of the waterjet technology longer follow-up, as well as incontinence models have to be studied.

Magnetic targeting of super-paramagnetic iron oxide nanoparticle labeled myogenic-induced adipose-derived stem cells in a rat model of stress urinary incontinence

Cell-based injectable therapy utilizing stem cells is a promising approach for the treatment of stress urinary incontinence (SUI). Applying a magnetically controlled cell delivery approach has enormous potential to enhance cell retention capability within the specified site. To assess the therapeutic efficacy of cellular magnetic targeting, we applied an external magnetic force to target an adipose-derived stem cell based therapy in a rat model of SUI. The results revealed that magnetic attraction of transplanted cells under the magnetic field was generated by cell uptake of superparamagnetic iron oxide nanoparticles in vitro. More importantly, magnetic targeting improved the retention rate of transplanted cells and facilitated the restoration of sphincter structure and function in a rat SUI model according to the results of histological examination and urodynamic testing. Therefore, magnetically guided targeting strategy might be a potential therapy method for treatment of SUI.

[Modern Therapy of Urinary Incontinence Using Muscle Stem Cells]

Modern Therapy of Urinary Incontinence Using Muscle Stem Cells Abstract. Urinary incontinence affects a large number of patients, and the cost of treatment continues to rise with the demographic change. There are various conservative and surgical therapies, which are often limited in their effect or limited in time. We are lacking long-term and sustainable solutions, whereas the treatment with a regenerative approach using stem cells forms a promising alternative. Various preclinical and clinical studies have investigated the use of precursor cells to strengthen the urinary sphincter muscle. This review discusses the issue of stress incontinence from the physiological point of view to conventional treatment and novel therapies using muscle stem cells. In addition, the authors inform about an ongoing prospective trial at the University Hospital in Zurich, which makes use of this modern and regenerative therapy form.

Applicability of regenerative medicine and tissue engineering for the treatment of stress urinary incontinence in female patients

Stress urinary incontinence (SUI) is an age health-related issue that generates interest due to its considerable public health burden and the controversies surrounding treatment. It is highly prevalent affecting 30-40% of all women during their lifetime. Midurethral slings are the standard of gold standard treatment for female patients with SUI. They have excellent short-term cure rates; however, their efficacy tends to decrease over time and patients often report urinary incontinence recurrence. This paper addresses the applicability of regenerative medicine and tissue engineering for the treatment of SUI in female patients. Cell-based treatment with periurethral injection of autologous adipose or muscle-derived stem cells have been used for SUI; however, the cure rates and SUI recurrence at 1 year were 40% and 70%, respectively. Novel minimally invasive approaches, such as low-intensity extracorporeal shock wave therapies have shown promising results in SUI animal models. In addition, local injection of growth factors, chemokines, and specific antibodies have shown histological evidence of neoangiogenesis, nerve, and sphincter regeneration in rodents and nonhuman primates with SUI. The use of bioactive factors and proteins secreted by cells, which is called secretomes, have been recognized as key regulators of various mechanisms, such as immunomodulation, angiogenesis, inflammation, apoptosis, and tissue repair. Emerging therapies aiming to replace or restore tissues and organ functionality may improve the long-term efficacy and in the near future may represent the standard of care for the treatment of SUI.

Advances in stem cell therapy for male stress urinary incontinence

INTRODUCTION

Among the several options that have been proposed in recent years for the management of male stress urinary incontinence (SUI), stem cell therapy represents a new frontier in treatment. The aim of this paper is to update the current status of stem cell therapy in animal and human studies for the management of iatrogenic male SUI.

AREAS COVERED

A literature review was conducted based on MEDLINE/PubMed searches for English articles using a combination of the following keywords: stem cell therapy, urinary incontinence, prostatectomy, regenerative medicine, mesenchymal stem cells.

EXPERT OPINION

The few studies reported in the literature have demonstrated short-term safety and promising results of stem cell therapy in treating male SUI. However, many aspects need to be clarified before stem cell therapy can be introduced into daily urologic practice. In fact, important issues such as the limitations of these studies in terms of small sample sizes and short follow-ups, the incomplete knowledge of the mechanism of action of stem cells, the technical details regarding the delivery method and the best sources of stem cells, the safety risks regarding genomic or epigenetic changes and potential immune reactions in the longer term need to be identified in more stringent clinical trials.

Intraurethral co-transplantation of bone marrow mesenchymal stem cells and muscle-derived cells improves the urethral closure

Background

Cell therapy constitutes an attractive alternative to treat stress urinary incontinence. Although promising results have been demonstrated in this field, the procedure requires further optimization. The most commonly proposed cell types for intraurethral injections are muscle derived cells (MDCs) and mesenchymal stem/stromal cell (MSCs). The aim of this study was to evaluate the effects of MDC-MSC co-transplantation into the urethra.

Methods

Autologous transplantation of labeled MDCs, bone marrow MSCs or co-transplantation of MDC-MSC were performed in aged multiparous female goats (n = 6 in each group). The mean number of cells injected per animal was 29.6 × 10⁶(± 4.3 × 10⁶). PBS-injected animals constituted the control group (n = 5). Each animal underwent urethral pressure profile (UPP) measurements before and after the injection procedure. The maximal urethral closure pressure (MUCP) and functional area (FA) of UPPs were calculated. The urethras were collected at the 28th or the 84th day after transplantation. The marker fluorochrome (DID) was visualized and quantified using in vivo imaging system in whole explants. Myogenic differentiation of the graft was immunohistochemically evaluated.

Results

The grafted cells were identified in all urethras collected at day 28 regardless of injected cell type. At this time point the strongest DID-derived signal (normalized to the number of injected cells) was noted in the co-transplanted group. There was a distinct decline in signal intensity between day 28 and day 84 in all types of transplantation. Both MSCs and MDCs contributed to striated muscle formation if transplanted directly to the external urethral sphincter. In the MSC group those events were rare. If cells were injected into the submucosal region they remained undifferentiated usually packed in clearly distinguishable depots. The mean increase in MUCP after transplantation in comparison to the pre-transplantation state in the MDC, MSC and MDC-MSC groups was 12.3% (± 11.2%, not significant (ns)), 8.2% (± 9.6%, ns) and 24.1% (± 3.1%, p = 0.02), respectively. The mean increase in FA after transplantation in the MDC, MSC and MDC-MSC groups amounted to 17.8% (± 15.4%, ns), 15.2% (± 12.9%, ns) and 17.8% (± 2.5%, p = 0.04), respectively.

Conclusions

The results suggest that MDC-MSC co-transplantation provides a greater chance of improvement in urethral closure than transplantation of each population alone.

Limited accuracy of transurethral and periurethral intrasphincteric injections of cellular suspension

AIMS

The efficacy of cell therapy in patients with stress urinary incontinence (SUI) is lower than expected. The aim of this study was to determine the injection accuracy rate both with transurethral and periurethral route.

METHODS

Autologous intraurethral cell transplantation was performed in female goats. The cells were injected either periurethrally (PERI group, two depots/animal, n = 8) or transurethrally (TRANS group, eight depots/animal, n = 11). Transurethral injections were performed under endoscopic guidance. The number and distribution of cell depots in urethras were analyzed in the three-step protocol: 1) screening of whole explants by in vivo imaging system; 2) systematic microscopic analysis of raw 10 μm cross-sections; 3) immunohistochemistry. As control, four urethras collected 1 day after transurethral transplantation were used. Episodes of cell suspension leakages after needle withdrawal were noted.

RESULTS

In all experimental animals depots were identified in the urethral wall 28 days after transplantation. The mean percentage of depots located in the urethral wall in relation to all performed injections amounted to 68.7% and 67.0% for PERI and TRANS groups, respectively. The mean proportions of depots which were identified in external urethral sphincter (EUS) amounted 18.8% and 17.1%, respectively. Suspension leakage was observed in 19% of transurethral injections.

CONCLUSIONS

Although majority of cell depots were administrated accurately into the urethral wall, the precise delivery of cells into EUS is limited regardless of injection method. The insufficient accuracy of cell delivery into EUS and cell suspension leakage can contribute to the low efficacy of cell therapy in human patients with SUI.

Urethral Sphincter Mechanism Incompetence in Dogs: An Update

Urethral sphincter mechanism incompetence (USMI) is the most common cause of acquired urinary incontinence in dogs. The pathogenesis of USMI is multifactorial and complex. Studies have shown variable results regarding the effects and timing of sterilization on the incidence of USMI. Diagnosis of USMI is often based on history, physical examination, and elimination of other differentials. Treatment options for USMI include medications, such as α-adrenergic agents and estrogen products, minimally-invasive urethral bulking procedures, surgical procedures (e.g., indwelling urethral occluders), or combination therapy. The overall prognosis for USMI is typically fair to good with long-term therapy.

Purified Human Skeletal Muscle-Derived Stem Cells Enhance the Repair and Regeneration in the Damaged Urethra

BACKGROUND

Postoperative damage of the urethral rhabdosphincter and nerve-vascular networks is a major complication of radical prostatectomy and generally causes incontinence and/or erectile dysfunction. The human skeletal muscle-derived stem cells, which have a synchronized reconstitution capacity of muscle-nerve-blood vessel units, were applied to this damage.

METHODS

Cells were enzymatically extracted from the human skeletal muscle, sorted using flow cytometry as CD34/45 (Sk-34) and CD29/34/45 (Sk-DN/29) fractions, and separately cultured/expanded in appropriate conditions within 2 weeks. Urethral damage was induced by manually removing one third of the wall of the muscle layer in nude rats. A mixture of expanded Sk-34 and Sk-DN/29 cells was applied on the damaged portion for the cell transplantation (CT) group. The same amount of media was used for the non-CT (NT) group. Urethral pressure profile was evaluated via electrical stimulation to assess functional recovery. Cell engraftments and differentiations were detected using immunohistochemistry and immunoelectron microscopy. Expression of angiogenic cytokines was also analyzed using reverse transcriptase-polymerase chain reaction and protein array.

RESULTS

At 6 weeks after transplantation, the CT group showed a significantly higher functional recovery than the NT group (70.2% and 39.1%, respectively; P < 0.05). Histological analysis revealed that the transplanted human cells differentiated into skeletal muscle fibers, nerve-related Schwann cells, perineuriums, and vascular pericytes. Active paracrine angiogenic cytokines in the mixed cells were also detected with enhanced vascular formation in vivo.

CONCLUSIONS

The transplantation of Sk-34 and Sk-DN/29 cells is potentially useful for the reconstitution of postoperative damage of the urethral rhabdosphincter and nerve-vascular networks.

In vivo imaging system for explants analysis-A new approach for assessment of cell transplantation effects in large animal models

Introduction

Despite spectacular progress in cellular transplantology, there are still many concerns about the fate of transplanted cells. More preclinical studies are needed, especially on large animal models, to bridge the translational gap between basic research and the clinic. Herein, we propose a novel approach in analysis of cell transplantation effects in large animals explants using in vivo imaging system (IVIS®) or similar equipment.

Material and methods

In the in vitro experiment cells labeled with fluorescent membrane dyes: DID (far red) or PKH26 (orange) were visualized with IVIS®. The correlation between the fluorescence signal and cell number with or without addition of minced muscle tissue was calculated. In the ex vivo study urethras obtained from goats after intraurethral cells (n = 9) or PBS (n = 4) injections were divided into 0.5 cm cross-slices and analyzed by using IVIS®. Automatic algorithm followed or not by manual setup was used to separate specific dye signal from tissue autofluorescence. The results were verified by systematic microscopic analysis of standard 10 μm specimens prepared from slices before and after immunohistochemical staining. Comparison of obtained data was performed using diagnostic test function.

Results

Fluorescence signal strength in IVIS® was directly proportional to the number of cells regardless of the dye used and detectable for minimum 0.25x10⁶ of cells. DID-derived signal was much less affected by the background signal in comparison to PKH26 in in vitro test. Using the IVIS® to scan explants in defined arrangement resulted in precise localization of DID but not PKH26 positive spots. Microscopic analysis of histological specimens confirmed the specificity (89%) and sensitivity (80%) of IVIS® assessment relative to DID dye. The procedure enabled successful immunohistochemical staining of specimens derived from analyzed slices.

Conclusions

The IVIS® system under appropriate conditions of visualization and analysis can be used as a method for ex vivo evaluation of cell transplantation effects. Presented protocol allows for evaluation of cell delivery precision rate, enables semi-quantitative assessment of signal, preselects material for further analysis without interfering with the tissue properties. Far red dyes are appropriate fluorophores to cell labeling for this application.

Cell therapy for stress urinary incontinence: Present-day frontiers

Stress urinary incontinence (SUI) significantly diminishes the quality of patients' lives. Currently available surgical and nonsurgical therapies remain far from ideal. At present, advances in cellular technologies have stirred growing interest in the use of autologous cell treatments aimed to regain urinary control. The objective was to conduct a review of the literature and analyse preclinical and clinical studies dedicated to various cell therapies for SUI, assessing their effectiveness, safety, and future prospects. A systematic literature search in PubMed was conducted using the following key terms: "stem," "cell," "stress," "urinary," and "incontinence." A total of 32 preclinical studies and 15 clinical studies published between 1946 and December 2014 were included in the review. Most preclinical trials have used muscle-derived stem cells and adipose-derived stem cells. However, at present, the application of other types of cells, such as human amniotic fluid stem muscle-derived progenitor cells and bone marrow mesenchymal stromal cells, is becoming more extensive. While the evidence shows that these therapies are effective and safe, further work is required to standardize surgical techniques, as well as to identify indications for their use, doses and number of doses. Future research will have to focus on clinical applications of cell therapies; namely, it will have to determine indications for their use, doses of cells, optimal surgical techniques and methods, attractive cell sources, as well as to develop clinically relevant animal models and make inroads into understanding the mechanisms of SUI improvement by cell therapies.

Precise injection of human mesenchymal stromal cells in the urethral sphincter complex of Göttingen minipigs without unspecific bulking effects

AIM

To investigate if injection of cells in the urethral sphincter complex causes unspecific bulking effects.

METHODS

Human mesenchymal stromal cells were isolated, expanded, and characterized. For transurethral injection, cells were labeled with the fluorescent dye PKH26 and in magnetic resonance imaging associated experiments with superparamagnetic particles. Aliquots of cells in 250 µL solvent were injected under vision in the urethral sphincter of immuno-suppressed Göttingen minipigs. Sphincteric closure pressure was recorded by standard and high-definition urethral pressure profilometry prior to and after cell injection. The animals were sacrificed after surgery or after 3 weeks, 3, 6, or 12 months of follow-up. The localisation of the injected cells was explored by histochemistry. Sham-treated animals served as controls.

RESULTS

PKH26-labeled cells survive injections in sphincter tissue samples by Williams cystoscopic injection needle well. In our animal study, the cellular depots were detected in the submucosa or in deeper zones of the sphincter, depending of the length of the injection needle (4-8 mm). Adverse effects associated with injection of cells or solvent such as a noteworthy bleeding, incontinence, or obstruction, were not recorded (n = 96 minipigs). However, a transient infiltration of macrophages was detected 3 weeks after cell injection. Changes in the urethral pressure profiles were not observed in cell-treated (n = 72) compared to sham-treated animals (n = 24).

CONCLUSIONS

Injection of small aliquots of cells to investigate cell therapies in minipigs is a feasible and safe procedure, and it does not bias the intrinsic urethral wall pressure.

The Anatomy of Caprine Female Urethra and Characteristics of Muscle and Bone Marrow Derived Caprine Cells for Autologous Cell Therapy Testing

Cell therapy is emerging as an alternative treatment of stress urinary incontinence. However, many aspects of the procedure require further optimization. A large animal model is needed to reliably test cell delivery methods. In this study, we aim to determine suitability of the goat as an experimental animal for testing intraurethral autologous cell transplantation in terms of urethral anatomy and cell culture parameters. The experiments were performed in 12 mature/aged female goats. Isolated caprine muscle derived cells (MDC) were myogenic in vitro and mesenchymal stem cells (MSC) population was able to differentiate into adipo-, osteo- and chondrogenic lineages. The median yield of cells after 3 weeks of culture amounted 47 × 10(6) for MDC and 37 × 10(6) for MSC. Urethral pressure profile measurements revealed the mean functional urethral length of 3.75 ± 0.7 cm. The mean maximal urethral closure pressure amounted 63.5 ± 5.9 cmH₂ O and the mean functional area was 123.3 ± 19.4 cm*cmH₂ O. The omega- shaped striated urethral sphincter was well developed in the middle and distal third of the urethra and its mean thickness on cross section was 2.3 mm. In the proximal part of the urethra only loosely arranged smooth muscle fibers were identified. To conclude, presented data demonstrate that caprine MDC and MSC can be expanded in vitro in a repeatable manner even when mature or aged animals are cell donors. Results suggest that female caprine urethra has similar parameters to those reported in human and therefore the goat can be an appropriate experimental animal for testing intraurethral cell transplantation. Anat Rec, 00:000-000, 2016. © 2016 Wiley Periodicals, Inc. Anat Rec, 300:577-588, 2017. © 2016 Wiley Periodicals, Inc.

Regenerative Medicine Therapies for Stress Urinary Incontinence

PURPOSE

We summarize the current state of knowledge regarding cell therapy for stress urinary incontinence and introduce new approaches of using regenerative pharmacology as an adjunct or replacement for cell therapy.

MATERIALS AND METHODS

We reviewed the literature by searching PubMed®, Ovid and Biological Abstracts. The period searched was 1975 to December 2015. The inclusion terms separately or in combination were stress urinary incontinence, cell therapy, chemokine, vascularization, innervation, secretome and/or animal models. Epublished articles were not included. We did not exclude articles based on impact factor.

RESULTS

Cell therapy is currently proposed to restore functional muscle cells and aid in closure of the sphincter in women with sphincter associated incontinence. Clinical trials have included small numbers of patients and results have varied depending on the patient cohorts and the cells used. Results of preclinical studies have also varied but show a more favorable outcome. This difference was most likely explained by the fact that animal modeling is not directly translatable to the human condition. However, preclinical studies have identified an exciting new approach to regeneration of the urinary sphincter using the components of cells (secretomes) or chemokines that home reparative cells to sites of injury.

CONCLUSIONS

Cell therapy will continue to be explored. However, a regenerative pharmacological approach to the treatment of stress urinary incontinence holds the promise of bypassing the lengthy and expensive process of cell isolation and also increasing the availability of treatment in many clinical settings. This approach requires careful preclinical modeling and attention to its health benefit-to-risk ratio.

Optimum anesthesia for reliable urethral pressure profilometry in female dogs and goats

OBJECTIVES

To investigate the effects of propofol and isoflurane on urethral pressure profilometry of female dogs and goats, and to identify the method of anesthesia that least influences urethral pressure profilometry and to assess its reproducibility.

METHODS

The effects of premedication with midazolam, propofol sedation and isoflurane anesthesia were assessed in five female dogs. The effects of propofol and isoflurane were compared in seven goats, whereas in another group of 19 goats, the state of deep propofol sedation was compared with the state of recovery from propofol sedation. The coefficient of reproducibility and within-subject coefficient of variation were calculated to evaluate test-retest reproducibility.

RESULTS

In conscious female dogs, maximal urethral closure pressure and functional area were significantly higher than under propofol or isoflurane (P = 0.04), but not different from the recovery state. In six of seven goats, maximal urethral closure pressure and functional area were higher when measured under propofol sedation than under isoflurane (median maximal urethral closure pressure, 69 vs 47 cmH2 O; P = 0.03). Maximal urethral closure pressure was lower under propofol than during recovery from propofol in 17 of 19 goats (median maximal urethral closure pressure, 54 vs 66 cmH2 O; P < 0.001). The test-retest coefficient of reproducibility for goats was 28 cmH2 O, and the within-subject coefficient of variation was 16%.

CONCLUSIONS

In dogs, urethral pressure profilometry should be measured in conscious animals whenever possible. In goats, urethral pressure profilometry is least affected during recovery from propofol sedation, and it shows acceptable reproducibility under this condition.

Noninvasive PET Imaging and Tracking of Engineered Human Muscle Precursor Cells for Skeletal Muscle Tissue Engineering

Transplantation of human muscle precursor cells (hMPCs) is envisioned for the treatment of various muscle diseases. However, a feasible noninvasive tool to monitor cell survival, migration, and integration into the host tissue is still missing.

METHODS

In this study, we designed an adenoviral delivery system to genetically modify hMPCs to express a signaling-deficient form of human dopamine D2 receptor (hD2R). The gene expression levels of the receptor were evaluated by reverse transcriptase polymerase chain reaction, and infection efficiency was evaluated by fluorescent microscopy. The viability, proliferation, and differentiation capacity of the transduced cells, as well as their myogenic phenotype, were determined by flow cytometry analysis and fluorescent microscopy. (18)F-fallypride and (18)F-fluoromisonidazole, two well-established PET radioligands, were assessed for their potential to image engineered hMPCs in a mouse model and their uptakes were evaluated at different time points after cell inoculation in vivo. Biodistribution studies, autoradiography, and PET experiments were performed to determine the extent of signal specificity. To address feasibility for tracking hMPCs in an in vivo model, the safety of the adenoviral gene delivery was evaluated. Finally, the harvested tissues were histologically examined to determine whether survival of the transplanted cells was sustained at different time points.

RESULTS

Adenoviral gene delivery was shown to be safe, with no detrimental effects on the primary human cells. The viability, proliferation, and differentiation capacity of the transduced cells were confirmed, and flow cytometry analysis and fluorescent microscopy showed that their myogenic phenotype was sustained. (18)F-fallypride and (18)F-fluoromisonidazole were successfully synthesized. Specific binding of (18)F-fallypride to hD2R hMPCs was demonstrated in vitro and in vivo. Furthermore, the (18)F-fluoromisonidazole signal was high at the early stages. Finally, sustained survival of the transplanted cells at different time points was confirmed histologically, with formation of muscle tissue at the site of injection.

CONCLUSION

Our proposed use of a signaling-deficient hD2R as a potent reporter for in vivo hMPC PET tracking by (18)F-fallypride is a significant step toward potential noninvasive tracking of hD2R hMPCs and bioengineered muscle tissues in the clinic.

Magnetization Transfer MR Imaging to Monitor Muscle Tissue Formation during Myogenic in Vivo Differentiation of Muscle Precursor Cells

Purpose To determine whether magnetization transfer (MT) magnetic resonance (MR) imaging may serve as a quantitative measure of the degree of fiber formation during differentiation of muscle precursor cells into engineered muscle tissue as a potential noninvasive monitoring tool in mice. Materials and Methods The study was approved by the local ethics committee (no. StV 01/2008) and the local Veterinary Office (license no. 99/2013). Human muscle progenitor cells (hMPCs) derived from rectus abdominis muscles were subcutaneously injected into CD-1 nude mice (CD-1 nude mice, Crl:CD1-Foxn1^nu; Charles River Laboratories, Wilmington, Mass) for development of muscle tissue. The mice underwent MR imaging examinations at 4.7 T at days 1, 3, 7, 14, 21, and 28 after cell transplantation by using a gradient-echo sequence with an MT prepulse and systematic variation of the off-resonance frequency (50-37 500 Hz) at an amplitude of 800°. Direct saturation was estimated from a Bloch equation simulation. The MT ratio (MTR) was correlated to immunohistochemistry findings, Western blot results, and results of myography. Data were analyzed by using one-way or two-way analysis of variance with the Sidak or Tukey multiple comparisons test. Results In the reference skeletal muscle, highest MT was found for 2500 Hz off-resonance frequency with an MTR ± standard deviation of 57.5% ± 3.5. The developing muscle tissue exhibited increasing MT values during the 28 days of myogenic in vivo differentiation and did not reach the values of native skeletal muscle. Mean values of MTR (2500 Hz) for hMPCs were 27.6% ± 6.3 (day 1), 24.7% ± 8.7 (day 3), 28.2% ± 5.7 (day 7), 35.9% ± 5.0 (day 14), 37.0% ± 7.9 (day 21), and 39.9% ± 8.1 (day 28). The results from MT MR imaging correlated qualitatively well with muscle tissue expression of specific skeletal markers, as well as muscle contractility. Conclusion MT MR imaging may be used to noninvasively monitor the process of myogenic in vivo differentiation of hMPCs as a biomarker of the quantity and quality of muscle fiber formation. ^© RSNA, 2016 Online supplemental material is available for this article.

Viability and MR detectability of iron labeled mesenchymal stem cells used for endoscopic injection into the porcine urethral sphincter

Direct stem cell therapies for functionally impaired tissue require a sufficient number of cells in the target region and a method for verifying the fate of the cells in the subsequent time course. In vivo MRI of iron labeled mesenchymal stem cells has been suggested to comply with these requirements. The study was conducted to evaluate proliferation, migration, differentiation and adhesion effects as well as the obtained iron load of an iron labeling strategy for mesenchymal stem cells. After injection into the porcine urethral sphincter, the labeled cells were monitored for up to six months using MRI. Mesenchymal stem cells were labeled with ferucarbotran (60/100/200 µg/mL) and ferumoxide (200 µg/mL) for the analysis of migration and viability. Phantom MR measurements were made to evaluate effects of iron labeling. For short and long term studies, the iron labeled cells were injected into the porcine urethral sphincter and monitored by MRI. High resolution anatomical images of the porcine urethral sphincter were applied for detection of the iron particles with a turbo-spin-echo sequence and a gradient-echo sequence with multiple TE values. The MR images were then compared with histological staining. The analysis of cell function after iron labeling showed no effects on proliferation or differentiation of the cells. Although the adherence increases with higher iron dose, the ability to migrate decreases as a presumed effect of iron labeling. The iron labeled mesenchymal stem cells were detectable in vivo in MRI and histological staining even six months after injection. Labeling with iron particles and subsequent evaluation with highly resolved three dimensional data acquisition allows sensitive tracking of cells injected into the porcine urethral sphincter for several months without substantial biological effects on mesenchymal stem cells.

Urovision 2020: The future of urology

Urology, as a specialty, has always been at the forefront of innovation and research. Newer technologies have been rapidly embraced and, in many cases, improved upon in order to achieve better patient outcomes. This review addresses the possible future directions that technological advances in urology may take. The role of further miniaturization of urolithiasis treatment, robotic surgery and other minimally invasive techniques is addressed. The potential for enhanced imaging and diagnostic techniques like magnetic resonance imaging and ultrasonography modifications, as well as the potential applications of nanotechnology and tissue engineering, are reviewed.

This article is based on the Dr. Sitharaman Best Essay award of the Urological Society of India for 2013.

Urinary incontinence in the bitch: an update

Urinary incontinence (UI), defined as the involuntary loss of urine during the filling phase of the bladder (Abrams et al. 2002), is a commonly seen problem in veterinary practice. Urinary sphincter mechanism incompetence (USMI) after spaying is the most common micturition disorder, and its medical treatment is normally successful, even though the underlying pathophysiological mechanism is not fully understood. Hormonal changes inducing structural and functional alterations in the bladder, as well as in the urethra composition, are discussed. To manage incontinent patients successfully, possible underlying abnormalities besides USMI should be ruled out. In the majority of cases, history, physical examination and simple tests including urinalysis and urine bacterial culture lead to a presumed aetiology. If USMI is the most likely cause, then the advantage of further diagnostic tests should be discussed with the owner before starting a trial therapy with alpha-adrenergic drugs. Potential side effects of this therapy have to be mentioned even though they rarely occur. It is important to thoroughly evaluate the success of the initial treatment. Its failure should lead to further diagnostic testing. Specialized clinical assessments may provide an aetiological diagnosis, and this could serve as a basis for discussing further treatment options. Surgical procedures, which may in rare cases cause irreversible side effects, may be instituted. If incontinence reoccurs after initial treatment was successfully performed, the diagnostic work-up including urinalysis should always be repeated. As results of urinalysis did not correlate well with results of bacterial culture, a urine culture is recommended (Comer and Ling 1981). Cystocentesis is the preferred method of urine collection (Bartges 2004). Equivocal results of quantitative cultures of urine samples obtained during midstream voiding or by catheterization require repeat collection by cystocentesis (Comer and Ling 1981).

Stress urinary incontinence animal models as a tool to study cell-based regenerative therapies targeting the urethral sphincter

Urinary incontinence (UI) is a major health problem causing a significant social and economic impact affecting more than 200million people (women and men) worldwide. Over the past few years researchers have been investigating cell therapy as a promising approach for the treatment of stress urinary incontinence (SUI) since such an approach may improve the function of a weakened sphincter. Currently, a diverse collection of SUI animal models is available. We describe the features of the different models of SUI/urethral dysfunction and the pros and cons of these animal models in regard to cell therapy applications. We also discuss different cell therapy approaches and cell types tested in preclinical animal models. Finally, we propose new research approaches and perspectives to ensure the use of cellular therapy becomes a real treatment option for SUI.

The dose-effect safety profile of skeletal muscle precursor cell therapy in a dog model of intrinsic urinary sphincter deficiency

Locally injected skeletal muscle precursor cells (skMPCs) integrate into and restore the muscle layers, innervation, vasculature, and function of the sphincter complex in animal models of intrinsic urinary sphincter deficiency (ISD). The goal of the present study was to test the dose-effect safety profile of skMPC therapy in a dog model of ISD. Sphincter deficiency was created in 20 adult female dogs by surgically removing the skeletal muscle layer of the urinary sphincter complex. skMPCs isolated from the hind leg were expanded in culture and injected 4 weeks later into the sphincter complex at a dose of 25 million cells (n = 5), 50 million cells (n = 5), or 100 million cells (n = 5) per milliliter in a 2-ml volume. Five dogs received no sphincter injection. The measures of maximal sphincter pressure, complete blood count, and blood chemistry were performed monthly until their sacrifice at 9 months. At that point, full necropsy was performed to assess the safety of the skMPC injections. Injection of different doses of cells had no effects on the body weight, blood cell count, or kidney or liver function test results (p > .05 among the skMPC doses). Some incidental pathologic features were found in the lower urinary tract in all groups and were most likely associated with repeat catheterization. The maximal urinary sphincter pressure was higher in the 50 million cells per milliliter treatment group than in the other experimental groups (p < .05). The findings of the present study have confirmed that urinary sphincter injection of skMPCs results in no significant local or systemic pathologic features within the dose range that improves sphincter pressures.

Viability, differentiation capacity, and detectability of super-paramagnetic iron oxide-labeled muscle precursor cells for magnetic-resonance imaging

Cell therapies are a promising approach for the treatment of a variety of human conditions including stress urinary incontinence, but their success greatly depends on the biodistribution, migration, survival, and differentiation of the transplanted cells. Noninvasive in vivo cell tracking therefore presents an important aspect for translation of such a procedure into the clinics. Upon labeling with superparamagnetic iron oxide (SPIO) nanoparticles, cells can be tracked by magnetic resonance imaging (MRI), but possible adverse effect of the labeling have to be considered when labeling stem cells with SPIOs. In this study, human muscle precursor cells (hMPC) were labeled with increasing concentrations of SPIO nanoparticles (100-1600 μg/mL) and cell viability and differentiation capacity upon labeling was assessed in vitro. While a linear dependence between cell viability and nanoparticle concentration could be observed, differentiation capacity was not affected by the presence of SPIOs. Using a nude mouse model, a concentration (400 μg/mL) could be defined that allows reliable detection of hMPCs by MRI but does not influence myogenic in vivo differentiation to mature and functional muscle tissue. This suggests that such an approach can be safely used in a clinical setting to track muscle regeneration in patients undergoing cell therapy without negative effects on the functionality of the bioengineered muscle.

Syngeneic Myoblast Transplantation Improves Muscle Function in a Murine Model of X-Linked Myotubular Myopathy

X-linked myotubular myopathy (XLMTM) is an isogenic muscle disease characterized by progressive wasting of skeletal muscle, weakness, and premature death of affected male offspring. Recently, the XLMTM gene knock-in mouse, Mtm1 p.R69C, was found to have a similar phenotype as the Mtm1 gene mutation in humans (e.g., central nucleation of small myofibers, attenuated muscle strength, and motor unit potentials). Using this rodent model, we investigated whether syngeneic cell therapy could mitigate muscle weakness. Donor skeletal muscle-derived myoblasts were isolated from C57BL6 wild-type (WT) and Mtm1 p.R69C (KI) mice for transplantation into the gastrocnemius muscle of recipient KI mice. Initial experiments demonstrated that donor skeletal muscle-derived myoblasts from WT and KI mice remained in the gastrocnemius muscle of the recipient KI mouse for up to 4 weeks posttransplantation. KI mice receiving syngeneic skeletal muscle-derived myoblasts displayed an increase in skeletal muscle mass, augmented force generation, and increased nerve-evoked skeletal muscle action potential amplitude. Taken together, these results support our hypothesis that syngeneic cell therapy may potentially be used to ameliorate muscle weakness and delay the progression of XLMTM, as application expands to other muscles.

Cell-based therapy for the deficient urinary sphincter

When sterile culture techniques of mammalian cells first became state of the art, there was tremendous anticipation that such cells could be eventually applied for therapeutic purposes. The discovery of adult human stem or progenitor cells further motivated scientists to pursue research in cell-based therapies. Although evidence from animal studies suggests that application of cells yields measurable benefits, in urology and many other disciplines, progenitor-cell-based therapies are not yet routinely clinically available. Stress urinary incontinence (SUI) is a condition affecting a large number of patients. The etiology of SUI includes, but is not limited to, degeneration of the urinary sphincter muscle tissue and loss of innervation, as well as anatomical and biomechanical causes. Therefore, different regimens were developed to treat SUI. However, at present, a curative functional treatment is not at hand. A progenitor-cell-based therapy that can tackle the etiology of incontinence, rather than the consequences, is a promising strategy. Therefore, several research teams have intensified their efforts to develop such a therapy for incontinence. Here, we introduce candidate stem and progenitor cells suitable for SUI treatment, show how the functional homogeneity and state of maturity of differentiated cells crucial for proper tissue integration can be assessed electrophysiologically prior to their clinical application, and discuss the trophic potential of adult mesenchymal stromal (or stem) cells in regeneration of neuronal function.

Towards a Treatment of Stress Urinary Incontinence: Application of Mesenchymal Stromal Cells for Regeneration of the Sphincter Muscle

Stress urinary incontinence is a significant social, medical, and economic problem. It is caused, at least in part, by degeneration of the sphincter muscle controlling the tightness of the urinary bladder. This muscular degeneration is characterized by a loss of muscle cells and a surplus of a fibrous connective tissue. In Western countries approximately 15% of all females and 10% of males are affected. The incidence is significantly higher among senior citizens, and more than 25% of the elderly suffer from incontinence. When other therapies, such as physical exercise, pharmacological intervention, or electrophysiological stimulation of the sphincter fail to improve the patient’s conditions, a cell-based therapy may improve the function of the sphincter muscle. Here, we briefly summarize current knowledge on stem cells suitable for therapy of urinary incontinence: mesenchymal stromal cells, urine-derived stem cells, and muscle-derived satellite cells. In addition, we report on ways to improve techniques for surgical navigation, injection of cells in the sphincter muscle, sensors for evaluation of post-treatment therapeutic outcome, and perspectives derived from recent pre-clinical studies.

Restoration of anal sphincter function after myoblast cell therapy in incontinent rats

Fecal incontinence (FI) remains a socially isolating condition with profound impact on quality of life for which autologous myoblast cell therapy represents an attractive treatment option. We developed an animal model of FI and investigated the possibility of improving sphincter function by intrasphincteric injection of syngeneic myoblasts. Several types of anal cryoinjuries were evaluated on anesthetized Fischer rats receiving analgesics. The minimal lesion yielding sustainable anal sphincter deficiency was a 90° cryoinjury of the sphincter, repeated after a 24-h interval. Anal sphincter pressure was evaluated longitudinally by anorectal manometry under local electrostimulation. Myoblasts were prepared using a protocol mimicking a clinical-grade process and further transduced with a GFP-encoding lentiviral vector before intrasphincteric injection. Experimental groups were uninjured controls, cryoinjured + PBS, and cryoinjured + myoblasts (different doses or injection site). Myoblast injection was well tolerated. Transferred myoblasts expressing GFP integrated into the sphincter and differentiated in situ into dystrophin-positive mature myofibers. Posttreatment sphincter pressures increased over time. At day 60, pressures in the treated group were significantly higher than those of PBS-injected controls and not significantly different from those of normal rats. Longitudinal follow-up showed stability of the therapeutic effect on sphincter function over a period of 6 months. Intrasphincteric myoblast injections at the lesion borders were equally as effective as intralesion administration, but an injection opposite to the lesion was not. These results provide proof of principle for myoblast cell therapy to treat FI in a rat model. This strategy is currently being evaluated in humans in a randomized double-blind placebo-controlled clinical trial.

The effect of endoscopic administration of autologous porcine muscle-derived cells into the urethral sphincter

OBJECTIVE

To verify the fate of autologous porcine myogenic cells after endoscopic administration into the urethral sphincter.

METHODS

This study was performed on pig animal models. The muscle-derived cells (MDCs) were isolated and identified. After the third passage, the 6 × 10(7) of PKH26 labeled cells were injected into the urethral sphincter using a urethrocystoscope. The urethras were collected after 28 days. To analyze the fate of injected cells, the PKH26 presence, the desmin expression, and the distribution of acetylcholine receptors were evaluated in the tissue sections. Moreover, the maximal urethral closure pressure (MUCP) was assessed in experimental and control groups at day 1 and day 28.

RESULTS

The isolated porcine MDCs expressed desmin and were able to differentiate into myotubes in vitro. At day 28 after the transplantation, the depots of PKH26-positive cells were observed in the muscular layer, but also in the submucosa. The staining for desmin revealed that cells located in the muscle layer were integrated with muscle fibers that possessed acetylcholine receptors. However, cells administered into nonmuscle tissue did not express desmin. Urethral pressure profilometry demonstrated no significant differences between MUCP in the transplanted group in comparison to the control group at day 28.

CONCLUSION

The present study demonstrates the successful endoscopic transplantation of myogenic cells into the urethral sphincter. The experiments indicated the key importance of precise cell administration in terms of their fate after the injection.

Long-term structural and functional effects of autologous muscle precursor cell therapy in a nonhuman primate model of urinary sphincter deficiency

PURPOSE

We measured the long-term efficacy of autologous muscle precursor cell therapy in premenopausal female nonhuman primates with sustained urinary sphincter deficiency.

MATERIALS AND METHODS

Urinary sphincter deficiency was created in adult premenopausal female cynomolgus monkeys by selectively cauterizing and then transecting the pudendal innervation to the sphincter complex. The monkeys were then treated (18) or not treated (18) with intra-urinary sphincter injections of 5 million autologous green fluorescent protein labeled skeletal muscle precursor cells. Four untreated, uninjured monkeys served as controls. Maximal urethral pressure measurement and corresponding histological analysis of the structural and cellular components of the sphincter complex were performed up to 12 months after injection.

RESULTS

Cell treatment produced sustained (12 months) increases in resting, somatic nerve stimulated and adrenergic nerve stimulated maximal urethral pressure, and a greater percent of sphincter area occupied by muscle as well as a decrease in the sphincter area occupied by collagen compared to the untreated group (each p>0.05). These results were within control values (each p>0.05). By 3 months after injection green fluorescent protein positive cells were found in the skeletal muscle layer, expressing desmin and connexin-43, and in the smooth muscle layer, expressing α-smooth muscle actin and connexin-43, and they were incorporated into the subendothelial vasculature, expressing Von Willebrand factor. Cell injected sphincter tissue contained a mixture of green fluorescent protein positive cells and predominantly green fluorescent protein negative cells.

CONCLUSIONS

Injected skeletal muscle progenitor cells incorporated into the injured sphincter complex resulted in long-term structural and functional restoration of the injured sphincter complex in this nonhuman primate model.

Myoblasts inhibit prostate cancer growth by paracrine secretion of tumor necrosis factor-α

PURPOSE

Myoblasts can form muscle fibers after transplantation. Therefore, they are envisioned as a treatment for urinary incontinence after radical prostatectomy. However, to our knowledge the safety of this treatment and the interaction of myoblasts with any remaining neighboring cancer are unknown. We investigated the interactions between myoblasts and prostate carcinoma cells in vitro and in vivo.

MATERIALS AND METHODS

Myoblasts isolated from the rectus abdominis were used in a series of co-culture experiments with prostate cancer cells and subcutaneously co-injected in vivo. Cell proliferation, cell cycle arrest and apoptosis of cancer in co-culture with myoblasts were assessed. Tumor volume and metastasis formation were evaluated in a mouse model. Tissue specific markers were assessed by immunohistochemistry, fluorescence activated cell sorting analysis, Western blot and real-time quantitative polymerase chain reaction.

RESULTS

Myoblasts in proximity to tumor provided paracrine tumor necrosis factor-α to their microenvironment, decreasing the tumor growth of all prostate cancer cell lines examined. Co-culture experiments revealed induction of cell cycle arrest, tumor death by apoptosis and increased myoblast differentiation. This effect was largely blocked by tumor necrosis factor-α inhibition. The same outcome was noted in a mouse model, in which co-injected human myoblasts also inhibited the tumor growth and metastasis formation of all prostate cancer cell lines evaluated.

CONCLUSIONS

Myoblasts restrict prostate cancer growth and limit metastasis formation by paracrine tumor necrosis factor-α secretion in vitro and in vivo.

Muscle-derived cells for treatment of iatrogenic sphincter damage and urinary incontinence in men

Introduction. Aim of this study was to assess the safety and efficacy of injection of autologous muscle-derived cells into the urinary sphincter for treatment of postprostatectomy urinary incontinence in men and to characterize the injected cells prior to transplantation. Methods. 222 male patients with stress urinary incontinence and sphincter damage after uroloical procedures were treated with transurethral injection of autologous muscle-derived cells. The transplanted cells were investigated after cultivation and prior to application by immunocytochemistry using different markers of myogenic differentiation. Feasibility and functionality assessment was achieved with a follow-up of at least 12 months. Results. Follow-up was at least 12 months. Of the 222 treated patients, 120 responded to therapy of whom 26 patients (12%) were continent, and 94 patients (42%) showed improvement. In 102 (46%) patients, the therapy was ineffective. Clinical improvement was observed on average 4.7 months after transplantation and continued in all improved patients. The cells injected into the sphincter were at least ~50% of myogenic origin and representative for early stages of muscle cell differentiation. Conclusions. Transurethral injection of muscle-derived cells into the damaged urethral sphincter of male patients is a safe procedure. Transplanted cells represent different phases of myogenic differentiation.