From: University of Illinois at Urbana-Champaign
Findings Challenge Notion Of Withholding Food To Fight Rotavirus
CHAMPAIGN, Ill. -- Malnutrition slows recovery from rotaviral infection, scientists say. Their new research, which challenges the long-accepted approach of withholding food to rest the bowels of infants and animals infected with the virus, documents what happens during recovery.
As part of a series of experiments, a team of University of Illinois nutritionists, animal scientists and veterinary pathobiologists compared the activity of the intestine of healthy neonatal pigs with those that were infected with rotavirus and fed either normally or subjected to protein-energy malnutrition. With diminished nourishment, rotavirus appeared to be recognized by T-cells sent by the immune system, but the task of intestinal epithelial cell recovery was slowed dramatically.
Malnourished pigs still had diarrhea 16 days after infection, while nourished piglets recovered in nine days. Using cellular and molecular techniques, researchers watched the epithelial cells, which absorb nutrients when healthy, as they became infected and began producing rotavirus. They also monitored the progress of T-cells and other immune responses.
Rotavirus strikes virtually every child before the age of four, usually in the first two years of life, and ultimately kills an estimated 870,000 children annually worldwide. There is no cure, although a vaccine became available late last year.
"Our data show that an animal responds to nourishment -- that it can still absorb and clear the infection even during the period of diarrhea," said H. Rex Gaskins, a professor of animal sciences and veterinary pathobiology and a researcher in the U. of I. Division of Nutritional Sciences. "If food is withheld, that is malnutrition. This work eventually will allow us to define what macronutrients, such as protein, carbohydrate or fat, are important for intestinal recovery from enteric infections."
The study, published in the April issue of the Journal of Nutrition, indicates that malnutrition affects the clearance of rotavirus more than immune responsiveness, suggesting that the new vaccine may be effective in developing countries where malnutrition is often present, Gaskins said.
"It appears that malnutrition does not affect the ability of the host to mount an immune response, but it affects the ability of the host to clear, or turn down, the inflammation that follows in the intestine after the response is launched," he said.
A soon-to-be published study, led by Gaskins and nutritionist Sharon Donovan, shows that intravenous nutritional therapy that is used for infants with diarrhea, because it bypasses the intestine, alters immune-cell activity. The findings suggest that oral nutrients may be required by the intestine to maintain structural integrity and for the development of local immune components.
The studies support the use of neonatal piglets as models for understanding nutrition and infectious disease interactions in human infants, said Gaskins, who in April will receive the American Society for Nutritional Sciences annual Bio-Serv Award in Experimental Nutrition.