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


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.
Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Richard A
RA
Ashley
Christopher C
CC
Roth
Blake W
BW
Palmer
Yusuf
Y
Kibar
Jonathan C
JC
Routh
Kar-Ming
KM
Fung
Dominic
D
Frimberger
Hsueh-Kung
HK
Lin
Bradley P
BP
Kropp
D000818:Animals; D003556:Cystitis / Q000209:etiology* / Q000473:pathology; D005260:Female; D005355:Fibrosis / Q000473:pathology; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000637:transplantation; D007421:Intestine, Small / Q000637:transplantation*; D009504:Neutrophils / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000502:physiology*; D013552:Swine; D001743:Urinary Bladder / Q000502:physiology*