Intrinsic myenteric denervation: A new model to increase the intestinal absorptive surface in short-bowel syndrome

Introduction. Short-bowel syndrome (SBS) is caused by resection of massive portions of the small intestine and is characterized by symptoms related to malabsorption, of which severe weight loss is the most apparent. Surgical treatments for SBS are not yet satisfactory. In rats, the myenteric denerva tion by benzalkonium chloride (BAC) leads to development of megaileum with visceral dilatation and mucosal hyperplasia and increases the intestinal tr ansit time. Such operation in the remaining intestinal segment after massiv e small bowel resection could increase the duration of contact between lumi nal nutrients and ileal mucosal epithelium, and furthermore, it could incre ase the superficial area of the mucosa. Thus, our aim in this study was to evaluate the epithelial morphology and body weight changes of animals after intrinsic ileal denervation associated with extensive small intestine rese ction. Material and methods. Wistar rats were submitted to resection of 80% of sma ll intestinal length (Group R). Another group (B) of animals also received topical serosal application of BAC 0.3%. Control animals were submitted to simulated surgery (Group C). Animals were weighed weekly and sacrificed aft er 90 days. Intestinal walls were collected for histological procedure and morphometry. Results. At the end of the experimental period all groups showed weight inc rease, which was reduced in the R group (P < 0.01). Interestingly, the dene rvated Group B showed a marked increase in weight, similar to the control a nimals. Morphometric analysis of the mucosal layer area showed a major incr ease in mucosal surface area, mainly in Group B. Conclusions. Our results showed that the ileal intrinsic denervation associ ated with massive intestinal resection induced an increase in the superfici al absorptive area and was able to improve the postsurgical conditions for the animals, with accentuated weight increase. This procedure may be a usef ul model for further studies related to the role of the enteric nervous sys tem on intestinal adaptations after extensive resections and may provide a new approach for the surgical treatment of short-bowel syndrome. (C) 1999 A cademic Press.