Effects of short-chain fatty acids and total parenteral nutrition on intestinal gene expression.

摘要

The supplementation of total parenteral nutrition (TPN) formulas with short chain fatty acids (SCFAs) increases glucose uptake and the expression of glucose transporters following intestinal resection. While several signals may be involved in intestinal adaptation, increases in proglucagon and early response genes mRNA levels are seen in non-resected animals receiving SCFA supplemented TPN. While the effects of a mixture of SCFAs are well documented, the relative contribution of the individual SCFAs is unknown. Butyrate is of interest as it is a preferred fuel of colonocytes, with documented effects on cellular proliferation and gene expression. Accordingly, this study was undertaken to determine the relative role of butyrate in initiating an adaptive response in non-resected rats receiving TPN. Animals received standard TPN for 66 hours, followed by 6 hours of either (a) standard TPN, (b) TPN supplemented with a mixture of SCFAs (60 mM total), (c) TPN supplemented with butyrate (9 mM). An oral control group was fed an elemental diet, similar in macronutrient content to the TPN, such that all animals received the same amount of energy daily. SCFAs increased ileal GLUT2 mRNA expression compared to the orally fed group. SCFAs also increased proglucagon mRNA expression as compared to the TPN group. The ileal protein abundance of SGLT1 was reduced by both TPN and butyrate compared to the orally fed group. No changes in Na +K+-ATPase or early response gene expression were found in this study. In conclusion, 9 mM butyrate was not able to mimic the effects of a 60 mM mixture of SCFAs on GLUT2 and proglucagon expression.