Restoration of functional motor units in a rat model of sphincter injury by muscle precursor cell autografts1

Tissue-engineered sub-urethral sling with muscle-derived cells for urethral sphincter regeneration in an animal model of stress urinary incontinence

BACKGROUND

Stress urinary incontinence (SUI) is a widespread condition affecting more than 200 million people worldwide. Common treatments for this condition include retropubic colposuspension, and pelvic sling methods, which use autologous grafts or synthetic materials to support the bladder neck and urethral sphincter. Although these treatments have a cure rate of over 80%, adverse effects and recurrence may still occur. Several studies have focused on the potential of cell therapy. Muscle-derived cells (MDCs) can be easily obtained from small biopsied striated muscular tissues and possess superior multi-lineage differentiation and self-renewal capacity.

METHODS

Based on the unique characteristics of MDCs and previous favorable results in muscle regeneration, we fabricated a chitosan-gelatin hydrogel sling loaded with MDCs in a rat model of SUI. Leak point pressure and histological indices regarding inflammation, muscular atrophy, and collagen density were assessed to compare the effectiveness of cell injection and cell-laden sling.

RESULTS

The level of LPP was significantly reduced in the MODEL group versus the control animals. The LPP level was considerably higher in CELL INJECTION, SLING, and CELL/SLING groups compared to the MODEL group but did not reach the significance threshold. The inflammation rate was significantly lower in the CELL/SLING group compared to the SLING group.

CONCLUSION

The CELL/SLING group showed less atrophy compared to the other experimental groups, indicating that the cells may have higher viability on SLING than through injection. This also suggests that in long-term studies, as the degradation rate of hydrogels increases, the function of cells will become more apparent.

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.

Large Animal Models for Investigating Cell Therapies of Stress Urinary Incontinence

Stress urinary incontinence (SUI) is a significant health concern for patients affected, impacting their quality of life severely. To investigate mechanisms contributing to SUI different animal models were developed. Incontinence was induced under defined conditions to explore the pathomechanisms involved, spontaneous recovery, or efficacy of therapies over time. The animal models were coined to mimic known SUI risk factors such as childbirth or surgical injury. However, animal models neither reflect the human situation completely nor the multiple mechanisms that ultimately contribute to the pathogenesis of SUI. In the past, most SUI animal studies took advantage of rodents or rabbits. Recent models present for instance transgenic rats developing severe obesity, to investigate metabolic interrelations between the disorder and incontinence. Using recombinant gene technologies, such as transgenic, gene knock-out or CRISPR-Cas animals may narrow the gap between the model and the clinical situation of patients. However, to investigate surgical regimens or cell therapies to improve or even cure SUI, large animal models such as pig, goat, dog and others provide several advantages. Among them, standard surgical instruments can be employed for minimally invasive transurethral diagnoses and therapies. We, therefore, focus in this review on large animal models of SUI.

Use of uniformly sized muscle fiber fragments for restoration of muscle tissue function

Treatment of extensive muscle loss due to traumatic injury, congenital defects, or tumor ablations is clinically challenging. The current treatment standard is grafting of autologous muscle flaps; however, significant donor site morbidity and graft tissue availability remain a problem. Alternatively, muscle fiber therapy has been attempted to treat muscle injury by transplanting single fibers into the defect site. However, irregularly organized long fibers resulted in low survivability due to delay in vascular and neural integration, thus limiting the therapeutic efficacy. Therefore, no effective method is available to permanently restore extensive muscle injuries. To address the current limitations, we developed a novel method that produces uniformly sized native muscle fiber fragments (MFFs) for muscle transplantation. We hypothesized that fragmentation of muscle fibers into small and uniformly sized fragments would allow for rapid reassembly and efficient engraftment within the defect site, resulting in accelerated recovery of muscle function. Our results demonstrate that the processed MFFs have a dimension of approximately 100 μm and contain living muscle cells on extracellular matrices. In preclinical animal studies using volumetric defect and urinary incontinence models, histological and functional analyses confirmed that the transplanted MFFs into the injury sites were able to effectively integrate with host muscle tissue, vascular, and neural systems, which resulted in significant improvement of muscle function and mass. These results indicate that the MFF technology platform is a promising therapeutic option for the restoration of muscle function and can be applied to various muscle defect and injury cases.

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.

Injected Human Muscle Precursor Cells Overexpressing PGC-1α Enhance Functional Muscle Regeneration after Trauma

While many groups demonstrated new muscle tissue formation after muscle precursor cell (MPC) injection, the capacity of these cells to heal muscle damage, for example, sphincter in stress urinary incontinence, in long-term is still limited. Therefore, the first goal of our project was to optimize the functional regenerative potential of hMPC by genetic modification to overexpress human peroxisome proliferator-activated receptor gamma coactivator 1-alpha (hPGC-1α), key regulator of exercise-mediated adaptation. Moreover, we aimed at establishing a feasible methodology for noninvasive PET visualization of implanted cells and their microenvironment in muscle crush injury model. PGC-1α-bioengineered muscles showed enhanced marker expression for myogenesis (α-actinin, MyHC, and Desmin), vascularization (VEGF), neuronal (ACHE), and mitochondrial (COXIV) activity. Consistently, use of hPGC-1α_hMPCs produced significantly increased contractile force one to three weeks postinjury. PET imaging showed distinct differences in radiotracer signals ([¹⁸F]Fallypride and [¹¹C]Raclopride (both targeting dopamine 2 receptors (D2R)) and [⁶⁴Cu]NODAGA-RGD (targeting neovascularization)) between GFP_hMPCs and hD2R_hPGC-1α_hMPCs. After muscle harvesting, inflammation levels were in parallel to radiotracer uptake amount, with significantly lower uptake in hPGC-1α overexpressing samples. In summary, we facilitated early functional muscle tissue regeneration, introducing a novel approach to improve skeletal muscle regeneration. Besides successful tracking of hMPCs in muscle crush injuries, we showed that in high-inflammation areas, the specificity of radioligands might be significantly reduced, addressing a possible bottleneck of neovascularization PET imaging.

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.

Establishing and monitoring of urethral sphincter deficiency in a large animal model

BACKGROUND

Different methods for induction and monitoring of urethral sphincter deficiency were explored in a large animal model.

METHODS

Sphincter deficiency was established in female pigs by dilatation and cauterization, and amount and frequencies of voiding were monitored and explored by pad test. Sphincteric closure pressures were recorded prior to and immediately after treatment of each animal, and on day 21 by two techniques: standard urethral pressure profilometry (s-UPP) and high-definition urethral pressure profilometry (HD-UPP). Tissue samples of the urethrae were analyzed by histochemistry (AZAN- and Sirius Red staining) and by immunohistochemistry detecting desmin and fast-myosin to depict muscular tissues.

RESULTS

After 3 weeks of observation animals treated by dilatation plus electrocautery presented with sphincter deficiency: measurements by both, s-UPP and HD-UPP demonstrated the maximal closure pressure reduced to baseline levels and a diminished area under the curve. Histological analyses documented, that dilatation yielded a pitted connective tissue and cauterization lead to muscle damage. Animals treated by either dilatation only or proximal injury only recovered within 3 weeks. By pad test no significant differences between untreated and treated animals or between the differently treated groups were recorded.

CONCLUSION

Significant urethral sphincter deficiency can be induced in female pigs by a combination of urethral dilatation and distal electrocautery. Sphincter deficiency can be measured by standard and high-definition urethral pressure profilometry. It was maintained over 21 days after induction and correlated with visible changes in the tissue structure of the distal urethra.

Efficacy and Initial Safety Profile of CXCL12 Treatment in a Rodent Model of Urinary Sphincter Deficiency

Disappointing results of skeletal muscle precursor cell (skMPC) therapy for women with intrinsic urinary sphincter deficiency (ISD) associated urinary incontinence has increased interest in alternative sphincter regenerative approaches. This study was to measure the safety and efficacy of the cell homing chemokine CXCL12 versus skMPCs in a rat model of ISD. Thirty‐six adult female Sprague Dawley rats were divided into 6 treatment (Tx) conditions: (a) no ISD/noTx [Control]; (b) ISD/noTx; (c) ISD + skMPCs; (d) ISD + 3.5 mg CXCL12; (e) ISD + 7mg CXCL12; and (f) ISD + 14 mg CXCL12. Tx's were injected directly into the sphincter complex 30 days post ISD and rats euthanized 30 days post Tx. Blood samples for measurements of kidney and liver function, white and red blood cell counts, were taken at baseline and at euthanasia. Leak point pressures (LPP) were measured prior to, and sphincter collagen/muscle content measured after, euthanasia. There were no effects of treatments on white or red/white blood cell counts, kidney/liver function tests or histopathology of the urinary sphincter complex or surrounding tissues. ISD lowered LPP 35% and sphincter muscle content by 17% versus control rats. CXCL12, but not skMPC injections, restored both LPP to control values in a dose‐dependent fashion. Both skMPCs and CXCL12 restored sphincter muscle content to control values. This chemokine approach may represent a novel therapeutic option for ISD and appears, at least short‐term, to produce little clinical or tissue pathology. Stem Cells Translational Medicine2017;6:1740–1746

Human Muscle Precursor Cells Overexpressing PGC-1α Enhance Early Skeletal Muscle Tissue Formation

Muscle precursor cells (MPCs) are activated satellite cells capable of muscle fiber reconstruction. Therefore, autologous MPC transplantation is envisioned for the treatment of muscle diseases. However, the density of MPCs, as well as their proliferation and differentiation potential, gradually declines with age. The goals of this research were to genetically modify human MPCs (hMPCs) to overexpress the peroxisome proliferator-activated receptor γ coactivator (PGC-1α), a key regulator of exercise-mediated adaptation, and thereby to enhance early skeletal muscle formation and quality. We were able to confirm the sustained myogenic phenotype of the genetically modified hMPCs. While maintaining their viability and proliferation potential, PGC-1α-modified hMPCs showed an enhanced myofiber formation capacity in vitro. Engineered muscle tissues were harvested 1, 2, and 4 weeks after subcutaneous injection of cell-collagen suspensions, and histological analysis confirmed the earlier myotube formation in PGC-1α-modified samples, predominantly of slow-twitch myofibers. Increased contractile protein levels were detected by Western blot. In summary, by genetically modifying hMPCs to overexpress PGC-1α, we were able to promote early muscle fiber formation in vitro and in vivo, with an initial switch to slow-type myofibers. Therefore, overexpressing PGC-1α is a novel strategy to further enhance skeletal muscle tissue engineering.

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.

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.

Prospective regenerative medicine therapies for obstetric trauma-induced fecal incontinence

Fecal incontinence is a major public health issue that has yet to be adequately addressed. Obstetric trauma and injury to the anal sphincter muscles are the most common cause of fecal incontinence. New therapies are emerging aimed at repair or regeneration of sphincter muscle and restoration of continence. While regenerative medicine offers an attractive option for fecal incontinence there are currently no validated techniques using this approach. Although many challenges are yet to be resolved, the advent of regenerative medicine is likely to offer disruptive technologies to treat and possibly prevent the onset of this devastating condition. This article provides a review on regenerative medicine approaches for treating fecal incontinence and a critique of the current landscape in this area.

Functional and histological evidence for the targeted therapy using biocompatible polycaprolactone beads and autologous myoblasts in a dog model of fecal incontinence

BACKGROUND

Injection of bulking agents into the anal canal is limited by several factors, including biological resorption, particle migration, and ongoing degradation of the injected bulking agent.

OBJECTIVE

We investigated whether an injection of polycaprolactone beads containing autologous myoblasts could improve sphincter function in a dog model of fecal incontinence.

DESIGN

The control sham surgery group underwent skin incision around the anal sphincter (n = 5). Fecal incontinence was induced by resecting 25% of the posterior internal/external anal sphincter in another 10 dogs. After 1 month of sphincter injury, dogs were then treated with (n = 5) or without (n = 5) polycaprolactone beads containing PKH-26-labeled autologous myoblasts.

SETTING

This study was conducted at the department of surgery in collaboration with the department of advanced materials.

OUTCOME MEASURES

Three months after injection treatment, the resting and contractile pressure differences of the anal sphincter were compared, and histopathological studies were performed.

RESULTS

The anal pressures in untreated dogs were significantly lower than those in the sham surgery group (p < 0.05). The resting and contractile pressure differences were higher in treated dogs than in untreated dogs (resting pressure difference: 0.7 ± 0.5 vs -0.6 ± 0.8 mmHg; coefficient of the difference in recovery rate, 0.38; 95% CI, 0.15-0.61, p = 0.001; contractile pressure difference: 1.1 ± 4.2 vs -3.9 ± 2.6 mmHg; coefficient, 1.63; 95% CI, 0.55-2.71, p = 0.003). Immunofluorescent staining confirmed that the myoblasts had differentiated and synthesized myosin heavy chain, as observed in vitro.

LIMITATIONS

This study was limited by the lack of comparison of injecting beads containing autologous myoblasts with injecting myoblasts alone.

CONCLUSION

This study shows that an injection of polycaprolactone beads containing autologous myoblasts may improve anal sphincter function in an animal model of fecal incontinence.

Prospects of stem cell treatment in benign urological diseases

Stem cells (SCs) are undifferentiated cells that are capable of self-renewal and differentiation and that therefore contribute to the renewal and repair of tissues. Their capacity for division, differentiation, and tissue regeneration is highly dependent on the surrounding environment. Several preclinical and clinical studies have utilized SCs in urological disorders. In this article, we review the current status of SC use in benign urological diseases (erectile dysfunction, Peyronie disease, infertility, and urinary incontinence), and we summarize the results of the preclinical and clinical trials that have been conducted.

External physical and biochemical stimulation to enhance skeletal muscle bioengineering

PURPOSE OF REVIEW

Cell based muscle tissue engineering carries the potential to revert the functional loss of muscle tissue caused by disease and trauma. Although muscle tissue can be bioengineered using various precursor cells, major limitations still remain.

RECENT FINDINGS

In the last decades several cellular pathways playing a crucial role in muscle tissue regeneration have been described. These pathways can be influenced by external stimuli and they not only orchestrate the regenerative process after physiologic wear and muscle trauma, but also play an important part in aging and maintaining the stem cell niche, which is required to maintain long-term muscle function.

SUMMARY

In this review article we will highlight possible new avenues using external physical and biochemical stimulation in order to optimize muscle bioengineering.

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.

Dual growth factor-loaded in situ gel-forming bulking agent: passive and bioactive effects for the treatment of urinary incontinence

Stress urinary incontinence (SUI) is one of the major medical problems for adult females and has a devastating effect on their quality of life. The major cause of the development of the SUI is dysfunction of the urethral supporting tissues as a result of aging and childbirth. In this study, in situ gel-forming bulking agent loaded with dual growth factors, nerve growth factor (NGF) and basic fibroblast growth factor (bFGF), was fabricated. The bulking agent consisted of three components; (i) polycaprolactone (PCL) beads, (ii) bFGF-loaded nanogels, and (iii) NGF-loaded in situ gel forming solution. The bulking agent can provide an initial passive bulking effect (from the PCL beads) and regenerate malfunctioning tissues around the urethra (from the sequential and continuous release of growth factors from the hydrogel) for the effective treatment of SUI. The PCL beads were located stably at the applied urethra site (urinary incontinent SD rat) without migration to provide a passive bulking effect. The sequential release of the growth factors (NGF within a week and bFGF for more than 4 weeks) from the bulking agent provided regeneration of damaged nerve and smooth muscle, and thus enhanced biological function around the urethra. From the findings, we suggest that dual growth factor (NGF and bFGF)-loaded in situ gel-forming bulking agent may be a promising injectable bioactive system for the treatment for SUI.

A novel animal model for external anal sphincter insufficiency

PURPOSE

Reliable animal models are essential to evaluate future therapeutic options like cell-based therapies for external anal sphincter insufficiency. The goal of our study was to describe the most reliable model for external sphincter muscle insufficiency by comparing three different methods to create sphincter muscle damage.

METHODS

In an experimental animal study, female Lewis rats (200-250 g) were randomly assigned to three treatment groups (n = 5, each group). The external sphincter muscle was weakened in the left dorsal quadrant by microsurgical excision, cryosurgery, or electrocoagulation by diathermy. Functional evaluation included in vivo measurements of resting pressure, spontaneous muscle contraction, and contraction in response to electrical stimulation of the afferent nerve at baseline and at 2, 4, and 6 weeks after sphincter injury. Masson's trichrome staining and immunofluorescence for skeletal muscle markers was performed for morphological analysis.

RESULTS

Peak contraction after electrical stimulation was significantly decreased after sphincter injury in all groups. Contraction forces recovered partially after cryosurgery and electrocoagulation but not after microsurgical excision. Morphological analysis revealed an incomplete destruction of the external sphincter muscle in the cryosurgery and electrocoagulation groups compared to the microsurgery group.

CONCLUSIONS

For the first time, three different models of external sphincter muscle insufficiency were directly compared. The animal model using microsurgical sphincter destruction offers the highest level of consistency regarding tissue damage and sphincter insufficiency, and therefore represents the most reliable model to evaluate future therapeutic options. In addition, this study represents a novel model to specifically test the external sphincter muscle function.

Regenerative medicine in urology

Repair and reconstruction of damaged tissues and organs has been a major issue in the medical field. Regenerative medicine and tissue engineering, as rapid evolving technologies, may offer alternative treatments and hope for patients with serious defects and end-stage diseases. Most urologic diseases could benefit from the development of regenerative medicine and tissue engineering. This article discusses the role of cells and materials in regenerative medicine, as well as the status of current role of regenerative medicine for the generation of specific urologic organs.

Applications of tissue engineering in the genitourinary tract

Congenital abnormalities and acquired disorders can lead to organ damage or loss of tissue within the genitourinary tract. For reconstructive purposes, tissue-engineering efforts are currently underway for virtually every type of tissue and organ within the urinary tract. Tissue engineering incorporates the fields of cell transplantation, materials science and engineering for the purpose of creating functional replacement tissue. This article reviews some of the principles of tissue engineering and some of the applications of these principles to the genitourinary tract.

Adipose-derived stem cells (ADSCs) and muscle precursor cells (MPCs) for the treatment of bladder voiding dysfunction

PURPOSE

Bladder outflow obstruction (BOO) is common in the elderly and can result in bladder voiding dysfunction (BVD) due to severe bladder muscle damage. The goal of this research was to evaluate the use of adult stem cells for the treatment of BVD due to decreased muscle contractility in a rat model.

MATERIALS AND METHODS

Adipose-derived stem cells (ADSCs) and muscle precursor cells (MPCs) were harvested from male Lewis rats and expanded in culture. BOO was induced by tying a suture around the urethra. Six weeks after obstruction, the development of BVD was confirmed by cystometric analysis in conscious rats, histology and molecular investigations. Injection of ADSCs or MPCs into the bladder wall and synchronous deligation was performed 6 weeks after the obstruction. After stem-cell treatment, morphological and functional changes were assessed. Age-matched rats and animals without cellular therapy but deligation-only served as controls.

RESULTS

Voiding pressures decreased progressively 6 weeks after obstruction with increased bladder capacities. Structural changes of the detrusor muscle occurred during the time of obstruction with an increased connective tissue-to-smooth muscle ratio and decreased SMA/smoothelin expression. After stem-cell injection, improved voiding pressures and voiding volumes were observed together with recovered tissue architecture. RT-PCR and Western blotting showed an up-regulation of important contractile proteins.

CONCLUSIONS

We established a reliable model for BVD and demonstrated that ADSCs and MPCs can prevent pathophysiological remodelling and provide regenerated bladder tissue and function.

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.

Autologous muscle-derived cells for the treatment of female stress urinary incontinence: a 2-year follow-up of a Polish investigation

AIMS

We evaluated the safety, feasibility and initial effects of therapy with muscle-derived cells (MDCs) for women with stress urinary incontinence (SUI).

METHODS

MDCs were isolated from an upper-arm muscle biopsy from 16 women with SUI. Cells were isolated by enzymatic digestion and expanded in vitro for 8-10 weeks. A quantity of 0.6-25 × 10(6) of the obtained cells were injected transurethrally into the urethral rhabdosphincter of women under local anesthesia. The cells were placed circumferentially at the 9, 12, and 3 O'clock positions with endoscopic guidance.

RESULTS

The initial results of the treatment of SUI with adult muscle-derived stem cells demonstrate the safety and feasibility of using these cells. The 2-year follow-up revealed a 75% success rate, with some patients achieving complete improvement (50%) and some patients achieving partial improvement (25%), suggesting that the prospects for this method are encouraging.

CONCLUSIONS

Stem cell therapy promises to become a minimally invasive method for the regeneration of the urethral rhabdosphincter muscle. Injecting a small number of cells does not preclude obtaining the desired therapeutic result.

Regenerative medicine as a new therapeutic strategy for lower urinary tract dysfunction

The use of regenerative medicine for the treatment of organic and functional disorders intractable to conventional treatment has increased worldwide. This innovative medical field might particularly hold promise for the treatment of life-threatening diseases or healing of irreplaceable organs, such as the heart, liver and brain. Dysfunction of the urogenital tract and associated organs other than the kidney might not have immediate life-threatening implications; furthermore, the effectiveness of alternative therapy, such as enterocystoplasty for bladder cancer, has been shown. Therefore, most physicians or scientists do not give much importance to these disorders. However, urological disease has increased in developed societies in recent years. Furthermore, medical costs have also escalated. Disorders of the lower urinary tract, such as urinary disturbance or incontinence, can lead to other complications, impairing quality of life and ultimately increasing short- and long-term medical expenses. Regenerative medicine might hold potential solutions to these problems. Recent advances in urogenital regenerative medicine are reviewed in the present article, with particular reference to lower urinary tract reconstruction. The potential of regenerative medicine for the treatment of intractable lower urinary tract dysfunction compared with conventional treatment is also discussed.

Periurethral skeletal myofibre implantation in patients with urinary incontinence and intrinsic sphincter deficiency: a phase I clinical trial

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Cell therapy using muscle precursor cell (MPC) injections has shown promise for urinary incontinence due to intrinsic sphincter deficiency (ISD), but the cell-preparation process is complex and costly. Implantation of freshly isolated myofibres carrying MPCs, mainly satellite cells, was very efficient in repairing muscle damage in recent animal experiments. In a phase I clinical trial, we investigated whether periurethral myofibre implantation generated local myogenesis and improved continence in 10 patients (five men and five women) with ISD. We found that myofibre implantation increased intraurethral pressure and periurethral electromyographic activity in patients with ISD. There were no serious side-effects.

OBJECTIVES

To assess the safety of periurethral myofibre implantation in patients with urinary incontinence due to intrinsic sphincter deficiency (ISD) To assess the resulting myogenic process and effects on urinary continence.

PATIENTS AND METHODS

An open-label non-randomised phase I clinical trial was conducted in five men and five women with ISD (mean age, 62.5 years). A free muscle strip from the patient's gracilis muscle was implanted around the urethra as a means to deliver locally myofibres and muscle precursor cells (MPCs). Patients were assessed for collection formation and incomplete bladder emptying. The maximum urethral closure pressure (MUCP) and concomitant periurethral electromyographic (EMG) activity were recorded before surgery and 1 and 3 months after surgery. Continence was assessed using the 24-h pad test and self-completed questionnaires, for 12 months.

RESULTS

There were no serious side-effects. Continence improved significantly during the 12-month follow-up in four of the five women, including two who recovered normal continence. In the women, MUCP increased two-fold and de novo EMG periurethral activity was recorded. In the men, MUCP and EMG recordings showed similar improvements but the effect on continence was moderate. The few patients enrolled could affect these results.

CONCLUSIONS

This is the first report of a one-step procedure for transferring autologous MPCs via myofibre implantation in patients with ISD. EMG and urodynamic assessments showed improvement of periurethral muscle activity. Further work is needed to confirm and improve the therapeutic efficiency of this procedure.

Autologous muscle derived cell therapy for stress urinary incontinence: a prospective, dose ranging study

PURPOSE

In this feasibility study we assessed the 12-month safety and potential efficacy of autologous muscle derived cells (Cook MyoSite Incorporated, Pittsburgh, Pennsylvania) as therapy for stress urinary incontinence.

MATERIALS AND METHODS

A total of 38 women in whom stress urinary incontinence had not improved with conservative therapy for 12 or more months underwent intrasphincter injection of low doses (1, 2, 4, 8 or 16 × 10(6)) or high doses (32, 64 or 128 × 10(6)) of autologous muscle derived cells, which were derived from biopsies of their quadriceps femoris. All patients could elect a second treatment of the same dose after 3-month followup. Assessments were made at 1, 3, 6 and 12 months after the last treatment. The primary end point was the incidence and severity of adverse events. In addition, changes in stress urinary incontinence severity were evaluated by pad test, diary of incontinence episodes and quality of life surveys.

RESULTS

Of the 38 patients 33 completed the study. Treatment related complications were limited to minor events such as pain/bruising at the biopsy and injection sites. Of patients who received 2 treatments of autologous muscle derived cells who were eligible for analysis, a higher percentage of those in the high dose vs the low dose group experienced a 50% or greater reduction in pad weight (88.9%, 8 of 9 vs 61.5%, 8 of 13), had a 50% or greater reduction in diary reported stress leaks (77.8%, 7 of 9 vs 53.3%, 8 of 15) and had 0 to 1 leaks during 3 days (88.9%, 8 of 9 vs 33.3%, 5 of 15) at final followup.

CONCLUSIONS

Injection of autologous muscle derived cells in a wide range of doses appears safe with no major treatment related adverse events reported. In addition, treatment with autologous muscle derived cells shows promise for relieving stress urinary incontinence symptoms and improving quality of life.

Ciliary neurotrophic factor (CNTF) promotes skeletal muscle progenitor cell (MPC) viability via the phosphatidylinositol 3-kinase-Akt pathway

Muscle progenitor cells (MPCs) are currently being investigated as cellular vectors to deliver neurotrophic factor (NF) for the promotion of re-innervation after axonal injury. Ideally NF delivery in such a model would enhance axonal regeneration while simultaneously promoting MPC viability. To date, insulin-like growth factor 1 (IGF-1) is one of the few NFs known to promote both re-innervation and MPC viability. We herein identify ciliary neurotrophic factor (CNTF) as a factor that promotes MPC viability in culture, and demonstrate CNTF to impart greater viability effects on MPCs than IGF-1. We demonstrate that pharmacological inhibition via LY294002 results in abrogation of CNTF-mediated viability, suggesting that the CNTF-mediated MPC viability benefit occurs via the PI3-Akt pathway. Finally, we employ a genetic model, establishing MPC cultures from mice deficient in class IA PI-3 K (p85α(-/-) ) mice, and demonstrate that the viability benefit imparted by CNTF is completely abrogated in PI-3 K-deficient MPCs compared to wild-type controls. In summary, our investigations define CNTF as a promoter of MPC viability beyond IGF-1, and reveal that the CNTF-mediated MPC viability effects occur via the PI3-Akt pathway.

A nonhuman primate model of stable urinary sphincter deficiency

PURPOSE

The pathophysiology of urinary sphincter deficiency in women remains incompletely understood and current treatment options have limitations. Female nonhuman primates may represent a relevant animal model for studies of pathophysiology and treatment interventions because of their human-like reproductive and age associated stages of life (premenopause, perimenopause and postmenopause), lower urinary tract structure and bipedal posture. We developed and characterized a nonhuman primate model of defined injury to the urethral sphincter complex.

MATERIALS AND METHODS

We used 22 adult female cynomolgus monkeys in which injury to the sphincter complex was created by cauterizing and then transecting its pudendal innervation. Urodynamic studies were performed before and during pudendal and hypogastric nerve stimulation at baseline, and 3, 6 and 12 months after injury. We also analyzed sphincter structure in vivo by cystourethrography, and ex vivo by quantitative histology and immunohistochemistry at these time points.

RESULTS

Injury produced a 47% to 50% decrease in maximal urethral pressure (vs baseline p <0.05). It also abolished the increase in maximal urethral pressure in response to pudendal and hypogastric nerve stimulation (vs baseline p >0.05), which persisted more than 12 months after injury. Urodynamic changes were consistent with decreased skeletal and smooth muscle content, decreased nerve responses and an associated decrease in somatic and adrenergic innervation in the sphincter complex.

CONCLUSIONS

These structural and urodynamic changes are consistent with those in patients with stress urinary incontinence. They support the usefulness of nonhuman primates as translatable surrogates for pathophysiological studies of urinary sphincter deficiency and testing novel therapies for that condition.

Muscle Precursor Cells for the Restoration of Irreversibly Damaged Sphincter Function

Multiple modalities, including injectable bulking agents and surgery, have been used to treat stress urinary incontinence. However, none of these methods is able to fully restore normal striated sphincter muscle function. In this study, we explored the possibility of achieving functional recovery of the urinary sphincter muscle using autologous muscle precursor cells (MPCs) as an injectable, cell-based therapy. A canine model of striated urinary sphincter insufficiency was created by microsurgically removing part of the sphincter muscle in 24 dogs. Autologous MPCs were obtained, expanded in culture, and injected into the damaged sphincter muscles of 12 animals. The animals were followed for up to 6 months after injection, and urodynamic studies, functional organ bath studies, ultrastructural and histological examinations were performed. Animals receiving MPC injections demonstrated sphincter pressures of approximately 80% of normal values, while the pressures in the control animals without cells dropped and remained at 20% of normal values. Histological analysis indicated that the implanted cells survived and formed tissue, including new innervated muscle fibers, within the injected region of the sphincter. These results indicate that autologous muscle precursor cells may be able to restore otherwise irreversibly damaged urinary sphincter function clinically.

Stress urinary incontinence and overactive bladder syndrome: current options and new targets for management

In the United States, office visits for women seeking treatment for urinary incontinence more than doubled between 1994 and 2000, from 1845 per 100 000 women. This review article addresses treatment options for 2 common types of incontinence in women: stress urinary incontinence (SUI) and detrusor overactivity (DO), commonly referred to as urge urinary incontinence (UUI). In the past, those with SUI typically faced limited treatment options, such as Kegel exercises, pessaries, or major surgery (Burch or Marshall-Marchetti-Krantz operations). However, treatment options for women also included anticholinergic medications, behavioral therapy, and implantable neuromodulation. In recent years, more options have become available. For women with SUI, a variety of minimally invasive synthetic midurethral sling approaches (eg, retropubic, transobturator, and single incision) and office-based procedures (eg, periurethral injection of bulking agents and radiofrequency collagen denaturation [Renessa®; Novasys Medical]) are now offered. More outpatient options will hopefully be available soon, including an inflatable, free-floating balloon to act as a shock absorber, and injection of muscle-derived stem cells into the periurethral tissue. Women with UUI now have targeted options, such as posterior tibial nerve stimulation (PTNS) and intravesical injections of onabotulinumtoxinA (Botox®; Allergan, Inc.), in addition to nonoral systemic medications.

Recovery of the injured external anal sphincter after injection of local or intravenous mesenchymal stem cells

OBJECTIVES

To understand the endogenous process of wound healing after anal sphincter injury and to determine possible mechanisms by which mesenchymal stem cells (MSCs) exert their regenerative potential.

METHODS

Virginal female rats (n=204) underwent anal sphincter laceration and repair. Thereafter, animals were randomly assigned to control injection, injection with intravenous MSCs, or direct injection of MSCs into the injured sphincter. Twenty uninjured animals served as baseline controls. Sphincters were analyzed for contractile function and parameters of wound healing 24 hours, 48 hours, 7 days, and 21 days after injury.

RESULTS

Direct injection of MSCs into the injured anal sphincter resulted in improved contractile function 21 days after injury compared with controls. Although expression of both proinflammatory (cyclooxygenase-2 and interleukin-6) and anti-inflammatory (interleukin-10 and tumor necrosis factor-α-stimulated gene-6) genes were increased dramatically and transiently after injury, MSCs did not alter this response. In contrast, transforming growth factor (TFG)-β1 (an important mediator of matrix deposition by mesenchymal cells) and lysyl oxidase (an enzyme important for synthesis of collagen and elastin) expression increased dramatically at earlier time points in the direct MSC injection group compared with controls. Increased expression of TFG-β1 and lysyl oxidase in directly injected sphincters was associated with increased collagen deposition and engraftment of MSCs in the sphincter.

CONCLUSION

In this preclinical animal model, direct, but not intravenous, injection of MSCs into the injured anal sphincter at the time of repair resulted in improved contractile function of the sphincter after injury, increased matrix deposition in the external anal sphincter, and increased expression of TFG-β1 and lysyl oxidase in the acute phase after injury.

Urethral distension as a novel method to simulate sphincter insufficiency in the porcine animal model

OBJECTIVES

To describe a novel animal model of intrinsic sphincter deficiency.

METHODS

The study was carried out on 10 female pigs. Injury to the urethral sphincter was induced by distension of the urethra. This was obtained by using the balloon of an 18-F Dufour catheter for 5 min followed by its retraction through the urethra without draining the balloon. The urethral pressure profile was evaluated before injury, immediately postinjury and at day 28 postinjury in the experimental group (n = 5), and on day 1 and day 28 in the control uninjured group (n = 5). The maximal urethral closure pressure, the functional urethral length and the area under curve of the urethral pressure profile were measured.

RESULTS

The mean maximal urethral closure pressure at the beginning of the experiment was 32 cmH(2) O, and the mean functional urethral length was 4.88 cm. The assessment at day 28 showed a reduction of the maximal urethral closure pressure (50% of the control, P > 0.05), the functional urethral length (52.5% of the control, P < 0.05) and the area under curve (52% of the control, P < 0.05) in injured pigs. Histologically, a fibrosis of the sphincter was detected without rupture of the muscle layer in all the samples.

CONCLUSIONS

The proposed porcine model can be used to obtain intrinsic sphincter deficiency-like urodynamic findings without rupturing the sphincter. This methodology can be applied to investigate therapies for intrinsic sphincter deficiency.

Autologous Bone Marrow-Derived Cells Regenerate Urethral Sphincters

Regenerative medicine based on tissue engineering and/or stem cell therapy techniques has the potential to improve irreversibly damaged tissues. Surgical injury to the lower urinary tract can occur as a result of radical prostatectomy or bladder neck surgery. Regeneration of urethral sphincters could be an effective treatment for post-surgical intrinsic sphincter deficiency (ISD)-related urinary incontinence. The replacement, enhancement, and/or recovery the urethral sphincter striated and smooth muscles could increase urethral closure pressure to help patients regain continence. Stem cells from muscle-derived satellite or adipose-derived mesenchymal cells provide temporary improvement in urethral closure pressure but do not reconstruct the muscle layer structures. Our strategy to accomplish regeneration of urethral sphincters is the utilization of autologous bone marrow-derived cells. We have developed a freeze injury model of ISD in rabbits. Freezing of the urinary sphincter causes loss of the majority of striated and smooth muscle cells, and causes a significant decrease in leak point pressure. In this review, we show that the autologous bone marrow-derived cells implanted within the freeze-injured sphincters differentiate into striated or smooth muscle cells. These cells then develop to reconstitute muscle layer structures within the sphincter. Furthermore, the leak point pressure of cell-implanted rabbits is significantly higher than that of cell-free injected controls. We conclude that implantation of autologous bone marrow-derived cells could be an effective treatment for human post-surgical ISD-related urinary incontinence.

Stem cell therapy for stress urinary incontinence: a critical review

Stress urinary incontinence (SUI) is a prevailing health problem that severely impacts quality of life. Because SUI is mainly due to urethral sphincter deficiency, several preclinical and clinical trials have investigated whether transplantation of patient's own skeletal muscle-derived cells (SkMDCs) can restore the sphincter musculature. The specific cell type of SkMDCs has been described as myoblasts, satellite cells, muscle progenitor cells, or muscle-derived stem cells, and thus may vary from study to study. In more recent years, other stem cell (SC) types have also been tested, including those from the bone marrow, umbilical cord blood, and adipose tissue. These studies were mostly preclinical and utilized rat SUI models that were established predominantly by pudendal or sciatic nerve injury. Less frequently used animal models were sphincter injury and vaginal distension. While transurethral injection of SCs was employed almost exclusively in clinical trials, periurethral injection was used in all preclinical trials. Intravenous injection was also used in one preclinical study. Functional assessment of therapeutic efficacy in preclinical studies has relied almost exclusively on leak point pressure measurement. Histological assessment examined the sphincter muscle content, existence of transplanted SCs, and possible differentiation of these SCs. While all of these studies reported favorable functional and histological outcomes, there are questions about the validity of the animal model and claims of multilineage differentiation. In any event, SC transplantation appears to be a promising treatment for SUI.

Long-term cryopreservation of pyramidalis muscle specimens as a source of striated muscle stem cells for treatment of post-prostatectomy stress urinary incontinence

BACKGROUND

Stem-cell injection into the degenerated external urethral sphincter is a new treatment modality for stress urinary incontinence (SUI). We examined the possibility of long-term cryopreserved pyramidalis muscle (PM) specimens as a source of striated muscle stem cells for the treatment of post-prostatectomy SUI.

METHODS

PM specimens were obtained from five male patients (mean age, 61-70 years) who underwent radical prostatectomy for prostate cancer. Specimens (volume, approximately 125 mm³ ) were obtained from the incisional edge, minced, and stored at -80°C in a freezing medium (Cell Banker 1®). After 24-60 months, the specimens were thawed and directly incubated at 37°C. Satellite cells were selectively cultured by magnetic affinity cell sorting using an anti-neural cell adhesion molecule (NCAM) antibody. Osteogenic and adipogenic differentiation were induced by bone morphogenic protein-7 (BMP-7) and γ-linolenic acid, respectively.

RESULTS

NCAM-positive cells (>99% purity) were selectively cultured from all cryopreserved PM specimens and confirmed as being of striated muscle origin by the expression of desmin and MyoD. They fused and differentiated into multinucleated myotubes 7 days after incubation in a differentiation induction medium. Stimulation by BMP-7 and γ-linolenic acid induced expression of alkaline phosphatase (osteoblast marker) and lipid deposition within the cytoplasm (adipocyte characteristic), respectively.

CONCLUSIONS

Long-term cryopreserved PM specimens can be used to culture muscle stem cells. Therefore, this method may be utilized for SUI treatment when necessary. Moreover, complete remove of the prostate gland without fear of injury to the urethral sphincter may be possible in patients with apical cancer or T3 prostate cancer.

The clinical relevance of cell-based therapy for the treatment of stress urinary incontinence

Stress urinary incontinence is a common disorder affecting the quality of life for millions of women worldwide. Effective surgical procedures involving synthetic permanent meshes exist, but significant short- and long-term complications occur. Cell-based therapy using autologous stem cells or progenitor cells presents an alternative approach, which aims at repairing the anatomical components of the urethral continence mechanism. In vitro expanded progenitor cells isolated from muscle biopsies have been most intensely investigated, and both preclinical trials and a few clinical trials have provided proof of concept for the idea. An initial enthusiasm caused by positive results from early clinical trials has been dampened by the recognition of scientific irregularities. At the same time, the safety issue for cell-based therapy has been highlighted by the appearance of new and comprehensive regulatory demands. The influence on the cost effectiveness, the clinical relevance and the future perspectives of the present clinical approach are discussed.

Development of cellular therapy for the treatment of stress urinary incontinence

Stress urinary incontinence (SUI) is highly prevalent and associated with a reduced quality of life. An intact rhabdosphincter at the mid-urethra is mandatory to maintain urinary continence. Adult stem cell injection therapy for the regenerative repair of an impaired sphincter is currently at the forefront of incontinence research. The implanted cells will fuse with muscle and release trophic factors promoting nerve and muscle integration. Hereby, we review the use of mesenchymal stem cell therapy for SUI and the experience with the development of muscle-derived stem cells.

Bioactive porous beads as an injectable urethral bulking agent: in vivo animal study for the treatment of urinary incontinence

In our previous study, growth factor (basic fibroblast growth factor [bFGF] or vascular endothelial growth factor)-immobilized polycaprolactone (PCL)/Pluronic F127 porous beads were fabricated by an isolated particle-melting/melt-molding particulate-leaching method. The growth factors were easily immobilized onto the pore surfaces of the PCL/F127 beads via heparin binding, and were continuously released for up to 28 days. In this study, the growth factor-immobilized porous beads were investigated for their potential use as an injectable urethral bulking agent for the treatment of stress urinary incontinence (SUI). From the in vivo study using Sprague-Dawley rats as an urinary incontinent animal model, it was observed that the growth factor (bFGF or vascular endothelial growth factor)-immobilized porous beads had effective cure behaviors for SUI as follows: the narrowed urethral lumen and the regeneration of smooth muscle around the urethra. In particular, the bFGF-immobilized PCL/F127 porous beads showed desirable smooth muscle regeneration and electrical contractility, which indicates it can be a good candidate as an injectable bioactive bulking agent for the treatment of SUI.

Implantation of autologous bone-marrow-derived cells reconstructs functional urethral sphincters in rabbits

The purpose of this study was to determine if implantation of autologous bone-marrow-derived cells has the potential to treat stress urinary incontinence caused by intrinsic sphincter deficiency. Bone marrow cells harvested from femurs of New Zealand White rabbits were cultured for 10 days. Seven days before implantation, the urethral sphincters located at the internal urethral orifice were cryo-injured by spraying liquid nitrogen for 15 s. The cultured autologous bone-marrow-derived cells were implanted 7 days after cryo-injury. For controls, cell-free solutions were injected. At 7 and 14 days after implantation, leak point pressures were determined and the urethral sphincters were examined by immunohistochemistry. At 7 and 14 days, the cell-implanted regions contained numerous striated and smooth muscle-like cells expressing myoglobin and smooth muscle actin, respectively. The proportions of myoglobin- and smooth muscle actin-expressing areas in both the 7- and 14-day cell-implanted regions were significantly higher than in controls. By 14 days, these differentiated cells formed contacts with similar cells, creating layered muscle structures. At that time, the leak point pressure of the cell-implanted rabbits was significantly higher than that of the controls. In conclusion, autologous bone-marrow-derived cells can reconstruct functional urethral sphincters.

Bone marrow mesenchymal stromal cell therapy for external urethral sphincter restoration in a rat model of stress urinary incontinence

OBJECTIVE

To assess the effect of intra-sphincteric injections of bone marrow mesenchymal stromal cells (MSCs) on Valsalva leak point pressure (VLPP) changes in an animal model of stress urinary incontinence (SUI).

MATERIALS AND METHODS

Twenty-four female Sprague-Dawley rats underwent bilateral pudendal nerve section to induce SUI. Six rats were SUI controls, 6 received periurethral injection of Plasma-Lyte (SUI placebo control) and 12 were given periurethral injection of PKH26-labeled MSCs. Four weeks after injection, conscious cystometry was undertaken in animals and VLPP recorded. All groups were sacrificed, and frozen urethra sections were submitted to pathology and immunohistochemistry assessment.

RESULTS

Rat MSCs were positive for the cell surface antigens CD44, CD73, CD90, and RT1A, and negative for CD31, CD45, and RT1B, confirming their stem cell phenotype. In vitro, differentiated MSCs expressed α-smooth muscle actin (SMA) and desmin, markers of smooth and striated muscles in vivo. Immunohistochemistry of rat urethras revealed PKH26-labeled MSCs in situ and at the injection site. LPP was significantly improved in animals injected with MSCs. Mean LPP was 24.28 ± 1.47 cmH(2) O in rats implanted with MSCs and 16.21 ± 1.26 cmH(2) O in SUI controls (P<0.001). Atrophic urethras with implanted MSCs were positively stained for myosin heavy chain and desmin.

CONCLUSION

Rat MSCs have the ability to differentiate and skew their phenotype towards smooth and striated muscles, as demonstrated by SMA up-regulation and desmin expression. Periurethral injection of MSCs in an animal model of SUI restored the damaged external urethral sphincter and significantly improved VLPP.