Use of the extracellular matrix from the porcine esophagus as a graft for bladder enlargement

Abstract

Introduction: Some patients with diseases that involve increased bladder pressure or low-capacity bladders may need bladder enlargement surgery. In current techniques for bladder enlargement, autologous tissue such as small intestine or colon tissue is used to perform cystoplasties, which is far from ideal for these patients. In search of biomaterials with appropriate regeneration and safety profiles, tissue engineering has resulted in preclinical studies with acellular matrices in animal models that have yielded positive preliminary results with respect to the urothelial cell and smooth muscle repopulation; these studies have primarily been performed with matrices originating from the bladder or intestinal submucosa.

Objective: The aim of the study was to assess an extracellular matrix device derived from the porcine esophagus for augmentation cystoplasty in an animal model.

Study design: Seven male Wistar rats weighing 357-390 g were subjected to augmentation cystoplasty with a circular segment of the acellular matrix from the porcine esophagus. Daily postoperative follow-up was performed with evaluation of changes in body weight, behavior, and wound status.

Results: During follow-up, there were no complications associated with the process. Three specimens were sacrificed at day 30, and three, at day 60. Necropsy was performed, with a description of the macroscopic findings and a morphological study. Epithelialization was observed, with different stages of mucosal development in all specimens analyzed. Repopulation of smooth muscle cells, mixed inflammatory infiltrate, and vascular neoformation were identified in the matrices.

Discussion: The urothelium and fibers of the smooth muscle were observed inside the implanted matrix. Additional investigations in larger animal models that allow urodynamic evaluation of the bladder with the matrix implanted are needed. However, to compare the results of this study model with those reported in the literature, a matrix derived from an organ different from the bladder was used because it could prevent the use of an intestinal segment in augmentation cystoplasty.

Conclusion: The acellular porcine esophagus matrix offers positive results regarding the repopulation of the urothelium and smooth muscle when used in augmentation cystoplasty in a murine model.

Keywords: Bladder enlargement; Bladder tissue engineering; Extracellular matrix; Urinary bladder surgery.