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

Exosome Therapy in Stress Urinary Incontinence: A Comprehensive Literature Review

Stress urinary incontinence (SUI) is characterized by the involuntary leakage of urine when bladder pressure exceeds urethral closing pressure during routine activities such as physical exertion, coughing, exercise, or sneezing. SUI is the most prevalent form of urinary incontinence, with a reported prevalence ranging from 10% to 70%, and its incidence increases with age. As the global population continues to age, the prevalence and clinical significance of SUI are expected to rise accordingly. The pathophysiology of SUI is primarily driven by two mechanisms: urethral hypermobility, resulting from compromised supporting structures, and intrinsic urethral sphincter deficiency, characterized by the deterioration of urethral mucosa and muscle tone. Current treatment options for SUI include conservative management strategies, which heavily rely on patient adherence and are associated with high recurrence rates, and surgical interventions, such as sling procedures, which offer effective solutions but are costly and carry the risk of adverse side effects. These limitations highlight the urgent need for more effective and comprehensive treatment modalities. Exosomes, nano-sized (30-150 nm) extracellular vesicles secreted by nearly all cell types, have emerged as a novel therapeutic option due to their regenerative, anti-fibrotic, pro-angiogenic, anti-apoptotic, anti-inflammatory, and anti-hypoxic properties. These biological functions position exosomes as a promising alternative to conventional therapies for SUI. Exosome therapy has the potential to enhance tissue regeneration, restore urethral function, and repair nerve and muscle damage, thereby reducing symptom burden and improving patients' quality of life. Additionally, exosome-based treatments could offer a less invasive alternative to surgery, potentially decreasing the need for repeated interventions and minimizing complications associated with current procedures. In this literature review, we critically assess the current state of research on the potential use of exosomes in treating SUI, highlighting their therapeutic mechanisms and potential clinical benefits.

Associations between metabolic score for visceral fat and urinary incontinence among US adult women: a population-based cross-sectional study

BACKGROUND

This study aimed to elucidate the association between metabolic score for visceral fat (METS-VF) and urinary incontinence (UI) prevalence among adult women in the US.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES, 2007-2016), the study conducted a cross-sectional analysis of 4,190 adult women aged ≥ 20 years. The investigation evaluated the relationship between METS-VF and the prevalence and severity of three types of UI: stress urinary incontinence (SUI), urgency urinary incontinence (UUI), and mixed urinary incontinence (MUI). Weighted multivariable logistic regression models and restricted cubic splines (RCS) were employed to assess these associations. Subgroup analyses and interaction tests were performed to explore potential modifying factors.

RESULTS

METS-VF was positively associated with the prevalence of SUI, UUI, and moderate to severe UI in the fully adjusted model. After categorizing METS-VF into quartiles, higher METS-VF quartiles were linked to increased susceptibility to all UI types, with a notable positive correlation observed for moderate and severe UI. RCS analysis revealed a nonlinear dose-response relationship between METS-VF and both UUI and MUI. Subgroup analyses and interaction tests suggested that age, ethnicity, and vaginal delivery times may influence the positive association between METS-VF and SUI.

CONCLUSION

METS-VF was positively associated with UI prevalence (SUI, UUI) and moderate to severe UI. These findings underscore the importance of visceral fat assessment in identifying individuals at risk for UI, offering novel insights for prevention and management strategies. METS-VF may serve as a practical tool for early risk stratification and personalized clinical interventions.

Association between SMAD3 and SMAD7 gene polymorphisms and susceptibility to stress urinary incontinence in Chinese women

OBJECTIVE

This study aimed to investigate the correlation between single nucleotide polymorphisms (SNPs) in SMAD3 and SMAD7 genes and the genetic risk of stress urinary incontinence (SUI) in Chinese women.

METHODS

A case-control study was conducted with 117 women diagnosed with SUI and 103 healthy controls. SNPs in SMAD3 (rs28683050, rs12901499) and SMAD7 (rs12953717, rs4939827) were analyzed using polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP). Allele and genotype frequencies were assessed using the SHEsis online platform. Epidemiological, clinical, and laboratory data were collected retrospectively. SUI patients underwent pelvic floor muscle training (PFMT), and treatment outcomes were evaluated after 3 months.

RESULTS

The G allele and GG genotype of rs12901499 in SMAD3 were significantly more common in the SUI case group (p_allele < 0.001, p_genotype = 0.002). Similarly, the T allele and TT genotype at rs12953717 in SMAD7 were more frequent in the SUI case group (p_allele = 0.002, p_genotype = 0.007). Multivariate logistic regression revealed that body mass index (BMI), family history, and the rs12901499 and rs12953717 polymorphisms were significant risk factors for SUI (P < 0.05). Furthermore, the TT genotype at rs12953717 was associated with poorer PFMT treatment outcomes.

CONCLUSION

Our findings suggest that the rs12901499 and rs12953717 polymorphisms are potential risk factors for SUI in women. Additionally, the rs12953717 polymorphism may influence the effectiveness of PFMT in SUI treatment.

Effect of controlled release of HGF on extracellular vesicle secretion by urine-derived stem cells

Introduction

The hepatic growth factor (HGF) stimulates DNA synthesis and cell proliferation and plays a role in tissue protection and regeneration. In this study, we have examined the effect of incubation of HGF with urine-derived stem cells (USCs) on the secretion of small extracellular vesicles (sEV) by the cells.

Materials and Methods

HGF in the incubation medium was either a bolus administration or a controlled release of an equivalent amount from microbeads within the size range of 50-200 µm made with ultrapurified low-viscosity high-guluronic acid (UP-LVG) alginate. USCs were incubated with or without HGF for 3 days or 7 days before removal of the incubation media, followed by harvesting sEV by the precipitation method. The protein content of isolated sEV was measured by bicinchoninic acid assay (BCA) for these three groups: control (no HGF beads), bolus HGF, and HGF beads. We also performed nanoparticle tracking analysis (NTA), Western blot assay, and ELISA for the HGF content of samples.

Results

We found a significantly higher concentration of proteins in the HGF microbead group (control release group) compared to the bolus group and the control group after 7 days (p < 0.0017). The NTA data aligned with the BCA; they showed a significantly higher concentration of particles within the size range of sEV (<200 nm) in the group treated with HGF beads compared to the two other groups on day 7 (p < 0.0001).

Conclusion

We found that administration of HGF to USCs by controlled release of the growth factor significantly enhances the levels of sEV secretion during 7 days of incubation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Whole body vibration training promotes proprioceptive pathway for the treatment of stress urinary incontinence in rats

Background

Stress urinary incontinence (SUI) is the most ubiquitous form of urinary incontinence in women. The therapeutic management of patients with SUI is challenging. The aim of this study is to evaluate the efficacy of whole body vibration training (WBVT) for SUI.

Methods

Thirty-five female rats were randomly divided into a sham group (Sham group, n=5), SUI + WBVT group (n=15) and SUI + whole body rest group (SUI + WBR group, n=15). The SUI + WBVT group was trained as follows: frequency 30 Hz, amplitude four mm, one min/repeat, four min rest, repeated 10 times, five days/week. After the intervention, five rats were taken on the 7th, 14th and 21st day to observe the urodynamic changes, levator ani muscle and dorsal root ganglia (DRG) morphology, and to observe the expression of neurotrophic factor-3/tyrosine protein kinase C (NT-3/TrkC) by Western blot.

Results

The urodynamic results showed that the difference in bladder leak point pressure/abdominal leak point pressure (BLPP/ALPP) between the Sham group and the SUI + WBR group was statistically significant (P<0.001) on 7th day, indicating successful modeling. The BLPP/ALPP of the SUI + WBVT group and the SUI + WBR group improved on 7th, 14th, and 21st day, and the BLPP/ALPP of SUI + WBVT group was higher than the SUI + WBR group. Compared with the Sham group, pathological changes appeared in the muscle shuttles in the SUI + WBVT group and SUI + WBR group. Western blot showed a gradual up-regulation of NT-3/TrkC.

Conclusions

WBVT can be used to treat SUI by affecting the expression of NT-3/TrkC, improving the structural morphology of the proprioceptors, and restoring the urinary control function. This study provides evidence for the clinical practice of WBVT. Future studies could further refine the behavioral and electrophysiological aspects of the assessment.

Association between exposure to multiple metals and stress urinary incontinence in women: a mixture approach

There is limited evidence linking exposure to heavy metals, especially mixed metals, to stress urinary incontinence (SUI). This study aimed to explore the relationship between multiple metals exposure and SUI in women. The data were derived from the National Health and Nutrition Examination Survey (NHANES), 2007-2020. In the study, a total of 13 metals were analyzed in blood and urine. In addition, 5155 adult women were included, of whom 2123 (41.2%) suffered from SUI. The logistic regression model and restricted cubic spline (RCS) were conducted to assess the association of single metal exposure with SUI risk. The Bayesian kernel machine regression (BKMR) and weighted quantile sum (WQS) were used to estimate the combined effect of multiple metals exposure on SUI. First, we observed that blood Pb, Hg and urinary Pb, Cd were positively related to SUI risk, whereas urinary W was inversely related by multivariate logistic regression (all p-FDR < 0.05). Additionally, a significant non-linear relationship between blood Hg and SUI risk was observed by RCS analysis. In the co-exposure models, WQS model showed that exposure to metal mixtures in blood [OR (95%CI) = 1.18 (1.06, 1.31)] and urine [OR (95%CI) = 1.18 (1.03, 1.34)] was positively associated with SUI risk, which was consistent with the results of BKMR model. A potential interaction was identified between Hg and Cd in urine. Hg and Cd were the main contributors to the combined effects. In summary, our study indicates that exposure to heavy metal mixtures may increase SUI risk in women.