Stem cell applications in regenerative medicine for stress urinary incontinence: A review of effectiveness based on clinical trials

Stem cell therapy combined with controlled release of growth factors for the treatment of sphincter dysfunction

Sphincter dysfunction often occurs at the end of tubule organs such as the urethra, anus, or gastroesophageal sphincters. It is the primary consequence of neuromuscular impairment caused by trauma, inflammation, and aging. Despite intensive efforts to recover sphincter function, pharmacological treatments have not achieved significant improvement. Cell- or growth factor-based therapy is a promising approach for neuromuscular regeneration and the recovery of sphincter function. However, a decrease in cell retention and viability, or the short half-life and rapid degradation of growth factors after implantation, remain obstacles to the translation of these therapies to the clinic. Natural biomaterials provide unique tools for controlled growth factor delivery, which leads to better outcomes for sphincter function recovery in vivo when stem cells and growth factors are co-administrated, in comparison to the delivery of single therapies. In this review, we discuss the role of stem cells combined with the controlled release of growth factors, the methods used for delivery, their potential therapeutic role in neuromuscular repair, and the outcomes of preclinical studies using combination therapy, with the hope of providing new therapeutic strategies to treat incontinence or sphincter dysfunction of the urethra, anus, or gastroesophageal tissues, respectively.

Advances in the molecular pathogenesis and cell therapy of stress urinary incontinence

Stress urinary incontinence (SUI) is very common in women. It affects patients' mental and physical health, and imposed huge socioeconomic pressure. The therapeutic effect of conservative treatment is limited, and depends heavily on patient persistence and compliance. Surgical treatment often brings procedure-related adverse complications and higher costs for patients. Therefore, it is necessary to better understand the potential molecular mechanisms underlying stress urinary incontinence and develop new treatment methods. Although some progress has been made in the basic research in recent years, the specific molecular pathogenic mechanisms of SUI are still unclear. Here, we reviewed the published studies on the molecular mechanisms associated with nerves, urethral muscles, periurethral connective tissue and hormones in the pathogenesis of SUI. In addition, we provide an update on the recent progresses in research on the use of cell therapy for treating SUI, including research on stem cells therapy, exosome differentiation and gene regulation.

Synovial Fluid Derived from Human Knee Osteoarthritis Increases the Viability of Human Adipose-Derived Stem Cells through Upregulation of FOSL1

Knee osteoarthritis (Knee OA) is an irreversible condition that causes bone deformity and degeneration of the articular cartilage that comprises the joints, resulting in chronic pain and movement disorders. The administration of cultured adipose-derived stem cells (ADSCs) into the knee joint cavity improves the clinical symptoms of Knee OA; however, the effect of synovial fluid (SF) filling the joint cavity on the injected ADSCs remains unclear. In this study, we investigated the effect of adding SF from Knee OA patients to cultured ADSCs prepared for therapeutic use in an environment that mimics the joint cavity. An increase in the viability of ADSCs was observed following the addition of SF. Gene expression profiling of SF-treated ADSCs using DNA microarrays revealed changes in several genes involved in cell survival. Of these genes, we focused on FOSL1, which is involved in the therapeutic effect of ADSCs and the survival and proliferation of cancer stem cells. We confirmed the upregulation of FOSL1 mRNA and protein expression using RT-PCR and western blot analysis, respectively. Next, we knocked down FOSL1 in ADSCs using siRNA and observed a decrease in cell viability, indicating the involvement of FOSL1 in the survival of ADSCs. Interestingly, in the knockdown cells, ADSC viability was also decreased by SF exposure. These results suggest that SF enhances cell viability by upregulating FOSL1 expression in ADSCs. For therapy using cultured ADSCs, the therapeutic effect of ADSCs may be further enhanced if an environment more conducive to the upregulation of FOSL1 expression in ADSCs can be established.

Current status of stem cell treatments and innovative approaches for stress urinary incontinence

Stem cells are capable of self-renewal, differentiation, and the promotion of the release of chemokines and progenitor cells essential for tissue regeneration. Stem cells have the potential to develop into specialized cells if given the right conditions, to self-renew and maintain themselves, to generate a large number of new differentiated cells if injured, and to either generate new tissues or repair existing ones. In the last decade, it has become clear that treating lower urinary tract dysfunction with the patient's own adult stem cells is an effective, root-cause method. Regenerative medicine is predicated on the idea that a damaged rhabdosphincter can be repaired, leading to enhanced blood flow and improved function of the sphincter's exterior (striated) and internal (smooth) muscles. Stem cell therapy has the potential to cure stress urinary incontinence according to preclinical models. In contrast, stem cell treatment has not been licensed for routine clinical usage. This article reviews the current state of stem cell for stres urinary incontinence research and recommends future avenues to facilitate practical uses of this potential therapy modality.

Tissue-engineered repair material for pelvic floor dysfunction

Pelvic floor dysfunction (PFD) is a highly prevalent urogynecology disorder affecting many women worldwide, with symptoms including pelvic organ prolapse (POP), stress urinary incontinence (SUI), fecal incontinence, and overactive bladder syndrome (OAB). At present, the clinical treatments of PFD are still conservative and symptom-based, including non-surgical treatment and surgery. Surgical repair is an effective and durable treatment for PFD, and synthetic and biological materials can be used to enforce or reinforce the diseased tissue. However, synthetic materials such as polypropylene patches caused a series of complications such as mesh erosion, exposure, pain, and inflammation. The poor mechanical properties and high degradation speed of the biomaterial meshes resulted in poor anatomical reduction effect and limitation to clinical application. Therefore, the current treatment options are suboptimal. Recently, tissue-engineered repair material (TERM) has been applied to repair PFD and could markedly improve the prognosis of POP and SUI repair surgery in animal models. We review the directions and progression of TERM in POP and SUI repair. Adipose-derived stem cells (ADSCs) and endometrial mesenchymal stem cells (eMSCs) appear to be suitable cell types for scaffold seeding and clinical implantation. The multidisciplinary therapy approach to tissue engineering is a promising direction for tissue repair. More and longer follow-up studies are needed before determining cell types and materials for PFD repair.

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.

Autologous Muscle-Derived Cell Therapy for Swallowing Impairment in Patients Following Treatment for Head and Neck Cancer

OBJECTIVES/HYPOTHESIS

To evaluate the safety and potential efficacy of autologous muscle-derived cells (AMDCs) for the treatment of swallowing impairment following treatment for oropharynx cancer.

STUDY DESIGN

Prospective, phase I, open label, clinical trial.

METHODS

Oropharynx cancer survivors disease free ≥2 years post chemoradiation were recruited. All patients had swallowing impairment but were not feeding tube dependent (Functional Oral Intake Scale [FOIS] ≥ 5). Muscle tissue (50-250 mg) was harvested from the vastus lateralis and 150 × 10⁶ AMDCs were prepared (Cook MyoSite Inc., Pittsburgh, PA). The cells were injected into four sites throughout the intrinsic tongue musculature. Participants were followed for 24 months. The primary outcome measure was safety. Secondary endpoints included objective measures on swallowing fluoroscopy, oral and pharyngeal pressure, and changes in patient-reported outcomes.

RESULTS

Ten individuals were enrolled. 100% (10/10) were male. The mean age of the cohort was 65 (±8.87) years. No serious adverse event occurred. Mean tongue pressure increased significantly from 26.3 (±11.1) to 31.8 (±9.5) kPa (P = .017). The mean penetration-aspiration scale did not significantly change from 5.6 (±2.1) to 6.8 (±1.8), and the mean FOIS did not significantly change from 5.4 (±0.5) to 4.6 (±0.7). The incidence of pneumonia was 30% (3/10) and only 10% (1/10) experienced deterioration in swallowing function throughout 2 years of follow-up. The mean eating assessment tool (EAT-10) did not significantly change from 24.1 (±5.57) to 21.3 (±6.3) (P = .12).

CONCLUSION

Results of this phase I clinical trial demonstrate that injection of 150 × 10⁶ AMDCs into the tongue is safe and may improve tongue strength, which is durable at 2 years. A blinded placebo-controlled trial is warranted.

LEVEL OF EVIDENCE

3 Laryngoscope, 132:523-527, 2022.

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.

[Diagnostic testing of female urinary incontinence: dos and dont's]

Urinary incontinence causes significant limitations in quality of life and reduces mental and physical health. It is a widespread and chronic disease. About 200 million people are affected by urinary incontinence worldwide. Females are more often affected than males. For the therapy of female urinary incontinence various conservative and surgical treatment measures are available. A comprehensive diagnostic work-up is crucial for effective and successful use of those therapeutical measures. The current paper gives a review of diagnostic options for female urinary incontinence: from non-invasive up to invasive investigations. It presents potential pitfalls and possibilities for improving the diagnostic work-up.