Physiological effects of human muscle-derived stem cell implantation on urethral smooth muscle function

Improved global response outcome after intradetrusor injection of adult muscle-derived cells for the treatment of underactive bladder

We report on the first regulatory approved clinical trial of a prospective open-label physician-initiated study assessing the safety and efficacy of intradetrusor injected Autologous Muscle Derived Cells (AMDC) treatment for underactive bladder (UAB). 20 non-neurogenic UAB patients were treated. Approximately 50-250 mg of quadriceps femoris muscle was collected using a spirotome 8-gauge needle. The muscle biopsy samples were sent to Cook MyoSite (Pittsburgh, PA) for processing, isolation, and propagation of cells. Research patients received approximately 30 intradetrusor injections of 0.5 mL delivered to the bladder, for a total of 15 mL and 125 million AMDC, performed utilizing a flexible cystoscope under direct vision using topical local anesthesia. Follow-up assessments included adverse events and efficacy via voiding diary and urodynamic testing at 1, 3, 6 and 12 months post-injection. An optional second injection was offered at the end of the 6 months visit. 20 patients received the first injection and all 20 patients requested and received a second injection. Median patient age was 65 years old (range 41-82 years). There were 16 male (80%) and 4 female (20%) patients. Etiology included 7 men (35%) with persistent urinary retention after transurethral resection of the prostate for benign prostatic hyperplasia and 13 patients (65%) with idiopathic chronic urinary retention. At the primary outcome time point of 12 months, 11/19 patients (58%) reported a global response assessment (GRA) ≥ 5, showing slight to marked improvement in their UAB symptoms, compared to 6/20 (30%) patients at 3 months post-injection. No serious procedure or treatment-related adverse events occurred. Noted improvements included: decreased post void residual urine volume, increased voiding efficiency, and decreased catheter use. Intradetrusor-injected AMDC as a treatment for UAB was successfully completed in a 20-patient trial without serious adverse event and with signal of efficacy. Cellular therapy may be a promising novel treatment for catheter-dependent chronic urinary retention. A multicenter controlled trial is needed to further assess the promise of regenerative medicine in the treatment of lower urinary tract dysfunction.

Biological characterization of adipose-derived regenerative cells used for the treatment of stress urinary incontinence

OBJECTIVE

To assess the characteristics of adipose-derived regenerative cells, and provide supportive data explaining the mechanism of efficacy observed for the use of these cells in the treatment of stress urinary incontinence.

METHODS

Adipose tissues were harvested by abdominal liposuction from healthy donors and patients with stress urinary incontinence. Adipose-derived regenerative cells were isolated from tissues using the Celution system, and assessed for their characteristics and ability to differentiate into smooth muscle cells.

RESULTS

Adipose-derived regenerative cells isolated by the Celution system developed into fibroblastic colonies. Flow cytometric analysis of adipose-derived stem cell markers showed that adipose-derived regenerative cells were positive for CD34 and CD44, and negative for CD31. Immunofluorescence staining after differentiation showed that colony-forming cells were positive for alpha-smooth muscle actin, calponin and desmin, which are smooth muscle cell markers. A cytokine release assay showed that adherent cells secreted cytokines associated with angiogenesis, including vascular endothelial growth factor-A, angiopoietin-2 and placental growth factor.

CONCLUSIONS

Adipose-derived regenerative cells collected by the Celution system might have clonogenic capacity and an angiogenetic function. These properties might contribute to the mechanisms through which regenerative cell therapy by periurethral injection of autologous adipose-derived regenerative cells ameliorates stress urinary 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.

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.

Tissue engineered bulking agent with adipose-derived stem cells and silk fibroin microspheres for the treatment of intrinsic urethral sphincter deficiency

In this study we developed a tissue engineered bulking agent that consisted of adipose-derived stem cells (ADSCs) and silk fibroin microspheres to treat stress urinary incontinence caused by severe intrinsic sphincter deficiency (ISD). ISD models were established by completely transection of the bilateral pudendal nerve (PNT) and confirmed by the decreased leak-point pressure (LPP) and increased lumen area of urethra. Injection of silk fibroin microspheres could recover LPP and lumen area at 4 weeks but its efficacy disappears at 8, 12 weeks. Moreover, it was exciting to find that tissue engineered bulking agent brought long-term efficacy (at 4, 8, 12 weeks post-injection) on the recovery of LPP and lumen area. Concomitantly with the function, tissue engineered bulking agent treated group also improved the urethral sphincter structure as exhibited by better tissue regeneration. The findings showed that silk fibroin microspheres alone could work effectively in short-term, while tissue engineered bulking agent that combined silk fibroin microspheres with ADSCs exhibited promising long-term efficacy. This study developed a new strategy of tissue engineered bulking agent for future ISD therapy.

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.

Human muscle-derived cell populations isolated by differential adhesion rates: phenotype and contribution to skeletal muscle regeneration in Mdx/SCID mice

Muscle-derived stem cells (MDSCs) isolated from murine skeletal tissue by the preplate method have displayed the capability to commit to the myogenic lineage and regenerate more efficiently than myoblasts in skeletal and cardiac muscle in murine Duchenne Muscular Dystrophy mice (mdx). However, until now, these studies have not been translated to human muscle cells. Here, we describe the isolation, by a preplate technique, of candidate human MDSCs, which exhibit myogenic and regenerative characteristics similar to their murine counterparts. Using the preplate isolation method, we compared cells that adhere faster to the flasks, preplate 2 (PP2), and cells that adhere slower, preplate 6 (PP6). The human PP6 cells express several markers of mesenchymal stem cells and are distinct from human PP2 (a myoblast-like population) based on their expression of CD146 and myogenic markers desmin and CD56. After transplantation to the gastrocnemius muscle of mdx/SCID mice, we observe significantly higher levels of PP6 cells participating in muscle regeneration as compared with the transplantation of PP2 cells. This study supports some previous findings related to mouse preplate cells, and also identifies some differences between mouse and human muscle preplate cells.

Stem cell therapy for incontinence: where are we now? What is the realistic potential?

A significant number of women experience stress urinary incontinence (SUI), which greatly affects their quality of life. Recent research investigating utilization of stem cells and their derivatives for the prevention and treatment of SUI has been performed to test the effect of cell source and method of administration in several animal models of SUI. The type of stem cell, timing of optimal dose or doses after injury, mechanism of action of stem cells, and route of administration must be investigated both preclinically and clinically before stem cell therapy becomes a possible treatment for SUI, although the future of this therapy looks promising. This article reviews the progress in stem cell research for incontinence and describes areas of future work as suggested by research in other fields.

Regeneration of skeletal muscle

Skeletal muscle has a robust capacity for regeneration following injury. However, few if any effective therapeutic options for volumetric muscle loss are available. Autologous muscle grafts or muscle transposition represent possible salvage procedures for the restoration of mass and function but these approaches have limited success and are plagued by associated donor site morbidity. Cell-based therapies are in their infancy and, to date, have largely focused on hereditary disorders such as Duchenne muscular dystrophy. An unequivocal need exists for regenerative medicine strategies that can enhance or induce de novo formation of functional skeletal muscle as a treatment for congenital absence or traumatic loss of tissue. In this review, the three stages of skeletal muscle regeneration and the potential pitfalls in the development of regenerative medicine strategies for the restoration of functional skeletal muscle in situ are discussed.

Urethral compensatory mechanisms to maintain urinary continence after pudendal nerve injury in female rats

INTRODUCTION AND HYPOTHESIS

This study was conducted to investigate the urethral compensatory mechanisms to maintain urinary continence after pudendal nerve injury.

METHODS

In naive, acute pudendal nerve transection (PNT) and 4 weeks after PNT (PNT-4w) female rats, leak point pressures (LPPs) during bladder compression were measured before and after the application of hexamethonium (C6), propranolol, and N (ω)-nitro-L: -arginine-methyl ester (L: -NAME), or terazosin and atropine. Responses to carbachol and phenylephrine of proximal and middle urethral muscle strips from naive and PNT-4w rats were also examined.

RESULTS

LPPs were significantly decreased in PNT rats but not in PNT-4w rats. LPPs in PNT rats were significantly increased by C6 or L-NAME while LPPs in PNT-4w rats were significantly decreased by C6, or terazosin and atropine. Excitatory responses to carbachol and phenylephrine in the proximal urethral muscle were significantly larger in PNT-4w rats.

CONCLUSIONS

These results suggest that α(1)-adrenoceptor and muscarinic receptor-mediated contractility is upregulated in the proximal urethra 4 weeks after PNT.

Bioactive porous beads as an injectable urethral bulking agent: their in vitro evaluation on smooth muscle cell differentiation

Growth factor (basic fibroblast growth factor or vascular endothelial growth factor)-immobilized polycaprolactone (PCL)/Pluronic F127 porous beads were prepared as an injectable bulking agent for effective treatment of urinary incontinence. The growth factor-immobilized porous beads may stimulate smooth muscle cell (SMC) differentiation of muscle-derived stem cells or defect tissues around urethra to improve the sphincter function (bioactive therapy) as well as to provide a bulking effect (passive therapy). The porous PCL/F127 beads were fabricated by an isolated particle-melting/melt-molding particulate-leaching method. The growth factors were easily immobilized onto the surfaces of the PCL/F127 porous beads via heparin binding and were continuously released for up to 28 days. Both growth factor-immobilized porous beads had a positive effect for the SMC differentiation of muscle-derived stem cells, as were demonstrated by the analyses of quantitative polymerase chain reactions, Western blot using SMC-specific markers, and immunohistochemical staining. In particular, the basic fibroblast growth factor-immobilized porous beads showed desirable SMC differentiation behavior that can be applied as an injectable bulking agent for the treatment of urinary incontinence.

Transplantation of muscle-derived stem cells plus biodegradable fibrin glue restores the urethral sphincter in a pudendal nerve-transected rat model

We investigated whether fibrin glue (FG) could promote urethral sphincter restoration in muscle-derived stem cell (MDSC)-based injection therapies in a pudendal nerve-transected (PNT) rat, which was used as a stress urinary incontinence (SUI) model. MDSCs were purified from the gastrocnemius muscles of 4-week-old inbred female SPF Wistar rats and labeled with green fluorescent protein. Animals were divided into five groups (N = 15): sham (S), PNT (D), PNT+FG injection (F), PNT+MDSC injection (M), and PNT+MDSC+FG injection (FM). Each group was subdivided into 1- and 4-week groups. One and 4 weeks after injection into the proximal urethra, leak point pressure (LPP) was measured to assess urethral resistance function. Histology and immunohistochemistry were performed 4 weeks after injection. LPP was increased significantly in FM and M animals after implantation compared to group D (P < 0.01), but was not different from group S. LPP was slightly higher in the FM group than in the M group but there was no significant difference between them at different times. Histological and immunohistochemical examination demonstrated increased numbers of surviving MDSCs (109 ± 19 vs 82 ± 11/hpf, P = 0.026), increased muscle/collagen ratio (0.40 ± 0.02 vs 0.34 ± 0.02, P = 0.044), as well as increased microvessel density (16.9 ± 0.6 vs 14.1 ± 0.4/hpf, P = 0.001) at the injection sites in FM compared to M animals. Fibrin glue may potentially improve the action of transplanted MDSCs to restore the histology and function of the urethral sphincter in a SUI rat model. Injection of MDSCs with fibrin glue may provide a novel cellular therapy method for SUI.