Regional variations in small intestinal submucosa evoke differences in inflammation with subsequent impact on tissue regeneration in the rat bladder augmentation model

Abstract

OBJECTIVE To examine the histological differences in the inflammatory response and regenerative outcomes of distal vs proximal porcine small intestinal submucosa (SIS) grafts in the rat bladder, as SIS from distal small intestine yields reliable and reproducible bladder regeneration, while SIS from proximal portions of small intestine does not provide similar results. MATERIALS AND METHODS In all, 30 Sprague‐Dawley rats underwent hemi‐cystectomy followed by anastomosis of a bladder patch of SIS prepared from either distal or proximal small intestine. After bladder harvest, immunohistochemistry was used to quantify mast cells, eosinophils, macrophages, and neutrophils (PMNs). Total cell count per unit area was compared across the time course in univariate and logistic regression modelling. RESULTS There were more eosinophils and mast cells in proximal SIS grafts, while there were more macrophages and PMNs in distal SIS grafts (all P < 0.05). Trichrome analysis showed increased collagen deposition in proximal SIS grafts and little smooth muscle regeneration. There was also significant graft contracture in proximal SIS grafts compared with distal SIS grafts (P < 0.05). CONCLUSIONS We conclude that the location of SIS origin may evoke different inflammatory responses, which results in altered bladder tissue regeneration.

Expression of VEGF and collagen using a latex biomembrane as bladder replacement in rabbits

“…On this basis, we confirmed the angiogenic potential of the membrane and demonstrated that the process is temporary, accompanying the reduction of the inflammatory process, important events for the lack of perpetuation of inadequate tissue response to the graft used. An explanation for this phenomenon could be the intense macrophage activity during the early phases of scarring (9), supporting the statement that these cells play a controlling role in fibroblast proliferation and migration, in matrix formation, and in angiogenesis (21,22).…”

Tissue Engineering for Tissue and Organ Regeneration

“…However, in two separate studies by Ashley et al, unseeded SIS would be found to be highly pro-inflammatory. (Ashley, 2009(Ashley, , 2010 The seminal work that laid the foundation for future bladder regenerative studies came from Oberpenning et al Within this study, autologous sources of canine urothelial and smooth muscle cells were harvested then seeded onto polymers and subsequently expanded ex vivo. Completely cystectomized canines were then transplanted with this new bladder construct and observed for approximately a year.…”

Aspects of Urological Tissue Engineering

“…However, in two separate studies by Ashley et al, unseeded SIS would be found to be highly pro-inflammatory. (Ashley, 2009(Ashley, , 2010 The seminal work that laid the foundation for future bladder regenerative studies came from Oberpenning et al (Oberpenning, 1999) Within this study, autologous sources of canine urothelial and smooth muscle cells were harvested then seeded onto polymers and subsequently expanded ex vivo. Completely cystectomized canines were then transplanted with this new bladder construct and observed for approximately a year.…”