Postoperative adaptation of the small intestine.

Abstract

AbstractFor nearly 100 years, the small intestine has been known to compensate for partial tissue loss. For only some 20 years has the phenomenon been studied in any depth, and a small proportion of these investigations has been undertaken in humans. Experimental and clinical data show that enteric mucosal hyperplasia in the remaining small bowel after enteric resection or bypass is accompanied by cytokinetic and functional adaptation. In general, the degree of adaptation depends on 3 factors: the amount of tissue excised or excluded, the particular enteric segment involved, and the presence or absence of a normal luminal stream. Thus, massive enterectomy can overwhelm the adaptive capacity of the gut, loss of jejunum is better tolerated than loss of terminal ileum, and total parenteral nutrition will abolish the compensatory response. The mechanisms that govern adaptive change are complex and interrelated. They involve both luminal agents (food, alimentary secretions) and humoral influences, of which enteroglucagon appears to be the most important. Wherever possible, small bowel operations should take account of adaptive phenomena in order to minimize metabolic and nutritional sequelae.