Malnutrition impairs postresection intestinal adaptation

Background: Postresection intestinal adaptation is influenced by several fa ctors, including luminal nutrients. Adaptation is impaired in the absence o f luminal nutrients, even if the nutrition is maintained via total parenter al nutrition (TPN). Reduced enteral intake also inhibits adaptation if maln utrition is present, but the mechanism has not been completely defined. Our aim was to study the effect of reduced enteral nutrition on adaptation and enterocyte production and death after 50% proximal resection in rats. Meth ods: Eighteen Lewis rats underwent either transection (n =6) or 50% proxima l resection (n =12). The resected animals either ate ad libitum (n =6) or w ere offered 75% of ad libitum intake (n =6). Nutritional status and intesti nal adaptation were determined 14 days after surgery. Results: Resected ani mals receiving 75% normal intake had decreased body weight (89% +/- 4% vs 1 12% +/- 2% and 112% +/- 1%, p < .05) and serum albumin (2.7 +/- 0.1 vs 3.2 +/- 0.0 g/dL and 3.0 +/- 0.1 g/dL, p < .05) compared with resection with no rmal intake and transection, respectively. Intestinal weight (0.32 +/- 03 v s 0.22 +/- 0.02 g/cm and 0.19 +/- 0.03 g/cm, p < .05) and diameter (10.5 +/ - 0.5 vs 8.5 +/- 1.0 mm and 7.8 +/- 0.8 mm, p < .05) increased after resect ion alone compared with transection and malnourished resection groups. Gut weight and diameter and villus height were lower in malnourished resected a nimals than with transection. Crypt cell production rate was significantly lower in the reduced intake animals. Apoptosis was increased in both crypt and villus enterocytes in normally nourished but not malnourished resected animals. Villus apoptosis correlated with villus height. Conclusions: Intes tinal adaptation is impaired by a 25% reduction in enteral nutrients, confi rming that both the route and quantity of nutrient intake are important in this process. Both enterocyte production and loss via apoptosis are decreas ed by reduced enteral intake and malnutrition after resection. The correlat ion between villus height and apoptosis suggests that the reduced apoptosis reflects the smaller enterocyte number in malnourished animals rather than an adaptive response to maintain intestinal structure.