Construction of cavernosum smooth muscle using umbilical artery smooth muscle cells seeded on acellular corporal collagen matrices.

The objective of this study was to investigate the feasibility of tissue engineering of corpus cavernosal smooth muscle. Acellular corporal collagen matrices (ACCMs) were obtained from the penis of adult rabbits by a cell removal procedure. ACCMs were implanted into the back muscles of allogenic rabbits to investigate the resulting immunological reaction. Human umbilical artery smooth muscle cells (HUASMCs) were isolated from human umbilical arteries through explant techniques and expanded in vitro. Subsequently, third and fifth passage HUASMCs were seeded to ACCMs at a concentration of 30 x 10(6) cells/mL. Then, seeded ACCMs were implanted subcutaneously in athymic mice. The implants were retrieved at 10, 20 and 40 days after implantation. Histochemistry, immunohistochemistry and scanning electron microscopy were performed to analyse the morphological characteristics of the engineered tissues. Additionally, organ bath studies were performed to address the contractility of the engineered tissues. The decellularization process successfully extracted all cellular components while preserving the original collagen fibers. The immunological reaction to ACCMs consisted of only a transient nonspecific inflammatory response. Light and scanning electron microscopy demonstrated that HUASMCs extended onto the three-dimensional ACCMs scaffolds in vitro. Histological analyses of the explants from all time points demonstrated a progressive regeneration of smooth muscle, with structures very similar to native corpus cavernosum smooth muscle. The maximum contraction force induced by phenylephrine and electrical stimulation were 3.64 +/- 0.18 g/100 mg and 2.50 +/- 0.21 g/100 mg, respectively. Our study demonstrates that HUASMCs can be seeded on three-dimensional ACCM scaffolds and will develop tissues similar to that of the native corpus cavernosum smooth muscle.