Functional evaluation of the grafted wall with porcine-derived small intestinal submucosa (SIS) to a stomach defect in rats.
BACKGROUND
Small intestinal submucosa (SIS) represents a novel bio-scaffolding material that may be used to repair hollow-organ defects. However, it is unclear whether neurophysiologic responses return to SIS-grafted areas in the gut. We evaluated the functional recovery of a stomach defect grafted with the porcine-derived SIS.


METHODS
Twelve rats had a full-thickness defect created in the stomach. SIS was secured to the gastric wall. After 6 months, muscle strips were harvested from within the grafted area to perform both a histologic and a functional study. Additional full-thickness muscle strips were harvested from the posterior in the same stomach as controls. A dose response curve was obtained with carbachol (CCH) or sodium nitroprusside (SNP). Activation of intrinsic nerves was achieved by electrical field stimulation (EFS).


RESULTS
The response to CCH and amplitude in EFS showed tonic contraction in both controls and SIS strips in a concentration-dependent and frequency-dependent manner. The magnitude after each stimulation was significantly lower in SIS strips compared with controls (P < .01). However, the contraction ratio of EFS to ED(50) of CCH was not significantly different between the groups. Additionally, SNP produced relaxation in both strips in a concentration-dependent manner. Histologic findings revealed that an insufficient amount of smooth-muscle cells existed in the muscularis propria, whereas compensated growth was observed in the submucosa with nerve regeneration.


CONCLUSIONS
This study demonstrates that SIS provides a template for nerve migration to the graft in the rodent stomach. Innervations showed a similar distribution to that observed in the controls. The clinical implications of such findings warrant additional investigation.
Ueno
Tomio
T
Department of Surgery, Duke University Medical Center, Durham, NC, USA. tommy@yamaguchi-u.ac.jp
de la Fuente
Sebastian G
SG
Abdel-Wahab
Omar I
OI
Takahashi
Toku
T
Gottfried
Marcia
M
Harris
Mary B
MB
Tatewaki
Makoto
M
Uemura
Kenichiro
K
Lawson
D Curtis
DC
Mantyh
Christopher R
CR
Pappas
Theodore N
TN
D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002465:Cell Movement / Q000502:physiology; D018679:Cholinergic Agonists / Q000494:pharmacology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D004558:Electric Stimulation; D007413:Intestinal Mucosa / Q000294:innervation / Q000473:pathology / Q000637:transplantation*; D007421:Intestine, Small / Q000294:innervation / Q000473:pathology / Q000637:transplantation*; D008297:Male; D023421:Models, Animal; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology*; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013270:Stomach / Q000294:innervation / Q000473:pathology / Q000601:surgery*; D013552:Swine; D016378:Tissue Transplantation / Q000379:methods*; D014183:Transplantation, Heterologous / Q000379:methods
D018679:Cholinergic Agonists; D018680:Cholinergic Antagonists; D009599:Nitroprusside; D002217:Carbachol