Myoblasts and fibroblasts in stress urinary incontinence

Small extracellular vesicles secreted by vaginal fibroblasts exert inhibitory effect in female stress urinary incontinence through regulating the function of fibroblasts

Stress urinary incontinence (SUI) is a common condition in women and associated with extra-cellular matrix (ECM) reconstruction, which is mainly regulated by fibroblasts. However, the underlying mechanism remains obscure. Small extracellular vesicles (sEVs) play fundamental biological roles in various cellular functions. Some studies suggested that the sEVs were involved in the metabolism of ECM and the function of fibroblasts. The purpose of our study was to investigate the effect of sEVs secreted by vaginal fibroblasts on the pathogenesis of SUI. We showed that the fibroblasts of female anterior vaginal wall secreted sEVs. Moreover, fibroblasts of females with SUI had significantly elevated secretion of sEVs. The collagen contents, proliferation and migration capacity of fibroblasts were decreased when fibroblasts were co-cultured with fibroblasts-derived sEVs (fibroblast-sEVs) from SUI patients. Proteomic analysis revealed that fibroblast-sEVs contained various differentially expressed proteins including TIMP2, TGF-β and ABCC4, which were involved in signaling pathways of fibroblasts regulation. Therefore, we suggested that fibroblast-sEVs contributed to the pathogenesis of SUI through various proteins including TIMP2, TGF-β and ABCC4.

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

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

Controlled release of insulin-like growth factor 1 enhances urethral sphincter function and histological structure in the treatment of female stress urinary incontinence in a rat model

OBJECTIVES

To determine the effects of controlled release of insulin-like growth factor 1 (IGF-1) from alginate-poly-L-ornithine-gelatine (A-PLO-G) microbeads on external urethral sphincter (EUS) tissue regeneration in a rat model of stress urinary incontinence (SUI), as SUI diminishes the quality of life of millions, particularly women who have delivered vaginally, which can injure the urethral sphincter. Despite several well-established treatments for SUI, growth factor therapy might provide an alternative to promote urethral sphincter repair.

MATERIALS AND METHODS

In all, 44 female Sprague-Dawley rats were randomised into four groups: vaginal distension (VD) followed by periurethral injection of IGF-1-A-PLO-G microbeads (VD + IGF-1 microbeads; 1 × 10⁴ microbeads/1 mL normal saline); VD + empty microbeads; VD + saline; or sham-VD + saline (sham).

RESULTS

Urethral function (leak-point pressure, LPP) was significantly lesser 1 week after VD + saline [mean (sem) 23.9 (1.3) cmH₂ O] or VD + empty microbeads [mean (sem) 21.7 (0.8) cmH₂ O) compared to the sham group [mean (sem) 44.4 (3.4) cmH₂ O; P < 0.05), indicating that the microbeads themselves do not create a bulking or obstructive effect in the urethra. The LPP was significantly higher 1 week after VD + IGF-1 microbeads [mean (sem) 28.4 (1.2) cmH₂ O] compared to VD + empty microbeads (P < 0.05), and was not significantly different from the LPP in sham rats, demonstrating an initiation of a reparative effect even at 1 week after VD. Histological analysis showed well-organised skeletal muscle fibres and vascular development in the EUS at 1 week after VD + IGF-1 microbeads, compared to substantial muscle fibre attenuation and disorganisation, and less vascular formation at 1 week after VD + saline or VD + empty microbeads.

CONCLUSION

Periurethral administration of IGF-1-A-PLO-G microbeads facilitates recovery from SUI by promoting skeletal myogenesis and revascularisation. This therapy is promising, but detailed and longer term studies in animal models and humans are needed.

Skeletal myogenic differentiation of urine-derived stem cells and angiogenesis using microbeads loaded with growth factors

To provide site-specific delivery and targeted release of growth factors to implanted urine-derived stem cells (USCs), we prepared microbeads of alginate containing growth factors. The growth factors included VEGF, IGF-1, FGF-1, PDGF, HGF and NGF. Radiolabeled growth factors were loaded separately and used to access the in vitro release from the microbeads with a gamma counter over 4 weeks. In vitro endothelial differentiation of USCs by the released VEGF from the microbeads in a separate experiment confirmed that the released growth factors from the microbeads were bioactive. USCs and microbeads were mixed with the collagen gel type 1 (2 mg/ml) and used for in vivo studies through subcutaneous injection into nude mice. Four weeks after subcutaneous injection, we found that grafted cell survival was improved and more cells expressed myogenic and endothelial cell transcripts and markers compared to controls. More vessel formation and innervations were observed in USCs combined with six growth factors cocktail incorporated in microbeads compared to controls. In conclusion, a combination of growth factors released locally from the alginate microbeads induced USCs to differentiate into a myogenic lineage, enhanced revascularization and innervation, and stimulated resident cell growth in vivo. This approach could potentially be used for cell therapy in the treatment of stress urinary incontinence.

Tissue Engineering for the Lower Urinary Tract: A Review of a State of the Art Approach

OBJECTIVES

Tissue engineering (TE) has become synonymous with physiological and functional reconstructive approaches in medicine. Although the goals of TE are ambitious and have not yet been attained, significant milestones have been achieved and future possibilities are great. To examine these possibilities with a special emphasis on the lower urinary tract, we provide a review of the development of TE techniques and a high-level overview of related regulatory and legal issues.

METHODS

Current trends in the field of TE, including the use of stem cells, scaffold optimization, and acellular tissue and growth factors, were reviewed and critically assessed through a comprehensive literature review using the PubMed database. Because of the rapid development of new TE approaches, recent abstracts from international urology conventions were included. A review of 2007 European Medicines Agency and Commission for Advanced Therapies legal regulations was also performed.

RESULTS

Although several clinical TE approaches have been developed, most lack objective validation. A variety of TE techniques are currently under development or investigation, but thus far, no one approach is clearly superior on the basis of significant long-term studies. A medical product based on TE and stem cells can be successfully developed only with careful consideration of legal and ethical regulations.

CONCLUSIONS

TE holds the promise for a tremendous impact on reconstructive urology. However, research must be focused and intensified for the full potential clinical benefits to be made widely available. Because the product development is affected by legal regulations, consensus must be achieved.