Imbalance in Brush Border Enzyme Activities as a Possible Cause of Hepatic Dysfunction after Jejunoileal Bypass in the Rat

Abstract

Previous work in our laboratory and in others suggest that protein malnutrition plays an important role in the pathogenesis of hepatic dysfunction after jejunoileal bypass for morbid obesity. This experimental study was undertaken to attempt to correlate hepatic dysfunction (the criterion used was the bromsulphalein clearance) to morphological and enzymatic adaptation of the functioning intestine in the rat. It was observed that the period of impaired bromsulphalein clearance is concomitant with a slight ileal morphological adaptation and especially with a period of selective adaptation of maltase and sucrase activities, whereas there is no increase in aminopeptidase activity. These data support the hypothesis that after jejunoileal bypass a preferential absorption of carbohydrates along with a protein deficiency state could occur and as in kwashiorkor it results in an impaired nutritional status, a major contributing factor to bypass-induced liver injury.

Effect of Chronic Alcohol Administration on Liver Morphology and on Brush Border Membrane Enzymes after Jejunoileal Bypass Operation in Rat

“…This surgical procedure led to a very significant increase in the brush border sucrase activity in the ileum but had no effect on this enzyme activity in the functioning jejunum of the shunt when compared to the corresponding segments of the sham-oper ated rats. These latter findings confirm simi lar results obtained previously [6,7,9], It is noteworthy that alcohol administra tion mainly led to two different responses in the intestinal segments of the sham-operated rats and after bypass operation. Indeed, in the sham-operated rats, alcohol provoked a stimulation of the disaccharidase activities in the proximal jejunum but had no effect on sucrase activity in the distal ileum.…”

“…Brush border lactase activity, normally ab sent in the distal ileum, did not appear in the ileal part of the functioning shunt after by pass. The fact that, after jejunoileal bypass operation, lactase activity was not stimulated in the functioning jejunum and ileum, shows that the remaining lactose-hydrolyzing ca-pacify of the functioning shunt is very low and that lactose malabsorption could be an important contributing factor to the often severe postoperative diarrhea [22], The pre ferential adaptation of disaccharidase activi ties after jejunoileal bypass operation, which is facilitated by alcohol ingestion, suggests preferential digestion of dietary carbohy drates leading progressively to a protein de privation state [9], For some investigators [23], the protein deprivation state in relation to dietary carbohydrate intake might explain the increased hepatic steatosis seen after in testinal bypass. Furthermore, protein depri vation may also been responsible, at least in part, for the rapid weight loss observed in our experimental conditions after bypass.…”

“…Although various surgical ap proaches have been suggested, reduction of the absorptive surface of the intestine by ex tensive jejunoileal bypass operation has been mostly used [1,2], After small bowel bypass or resection, numerous adaptive changes oc cur in the remaining functional intestinal mucosa, promoting hypertrophy of the intes tinal wall and increasing cellular proliferation [3,4], Furthermore, changes in the specific activity of the disaccharidases and peptidases have been described in the intestinal mucosa of man and animals following bypass, but the results were conflicting [3,[5][6][7][8][9]. It is well established that intestinal enzymes are af fected by various factors including dietary factors.…”