Vaginal reconstruction with a double-sided biomembrane-a preclinical experimental study on large animals

Tissue engineering techniques bring the promise of vaginal reconstruction with low invasiveness and fewer complications. However, existing biomaterial scaffolds remain limited in efficient vaginal recovery, focusing only on regenerating an epithelial layer, but muscle layers are missing or abnormal. The lack of a multi-tissue hierarchical structure in the reconstructed vagina leads to shrinking, stenosis, and fibrosis. Here, an acellular matrix named a double-sided biomembrane (DBM) is demonstrated for vaginal recovery. The regeneration of epithelial and muscle layers is achieved simultaneously since the smooth side of the DBM is helpful for guiding epithelial cell growth, while its loose and porous side guides muscle cell growth. In addition, the DBM demonstrates excellent mechanical properties similar to vaginal tissue, and hydrophilicity. Therefore, neovaginas were observed in the fourth and twelfth weeks after DBMs were transplanted to repair full-thickness vaginal defects (4 cm) that we established in large animals. The DBMs can effectively promote rapid epithelialization, the formation of large muscle bundles, higher rates of angiogenesis, and the restoration of physiological function in a neovagina. That is, the injured vagina achieves nearly complete recovery in anatomy and function, similar to a normal vagina. These preclinical results indicate that the DBM has prospects for vaginal injury repair. In brief, a portion of the vagina (4 cm) was removed in minipigs and replaced with an equal-sized DBM. The neovagina finally showed no significant difference from the normal vagina.