Cell sheet formation enhances the therapeutic effects of adipose-derived stromal vascular fraction on urethral stricture.

Urethral stricture (US) is a common disease in urology, lacking effective treatment options. Although injecting a stem cells suspension into the affected area has shown therapeutic benefits, challenges such as low retention rate and limited efficacy hinder the clinical application of stem cells. This study evaluates the therapeutic impact and the mechanism of adipose-derived vascular fraction (SVF) combined with cell sheet engineering technique on urethral fibrosis in a rat model of US. The results showed that SVF-cell sheets exhibit positive expression of α-SMA, CD31, CD34, Stro-1, and eNOS. In vivo study showed less collagen deposition, low urethral fibrosis, and minimal tissue alteration in the group receiving cell sheet transplantation. Furthermore, the formation of a three-dimensional (3D) tissue-like structure by the cell sheets enhances the paracrine effect of SVF, facilitates the infiltration of M2 macrophages, and suppresses the TGF-β/Smad2 pathway through HGF secretion, thereby exerting antifibrotic effects. Small animal in vivo imaging demonstrates improved retention of SVF cells at the damaged urethra site with cell sheet application. Our results suggest that SVF combined with cell sheet technology more efficiently inhibits the early stages of urethral fibrosis.