Parenteral nutrition and fasting reduces mucosal addressin cellular adhesion molecule-1 (MAdCAM-1) mRNA in Peyer's patches of mice.

BACKGROUND

Mucosal addressin cellular adhesion molecule-1 (MAdCAM-1) in Peyer's patches (PP) is the gateway molecule for cellular migration into the mucosal immune system. Lack of enteral feeding during parenteral nutrition (PN) rapidly decreases PP MAdCAM-1, leading to drops in mucosal T and B cells and intestinal and respiratory IgA. We determined the molecular events associated with MAdCAM-1 mRNA and protein during PN (short and long term) and fasting (1 and 2 days).

METHODS

Experiment 1: Cannulated mice received PN for 8 hours (short-term PN, n = 6) or chow + saline (chow, n = 6). Experiment 2: Cannulated mice received PN (long-term PN, n = 4) or chow (n = 3) for 5 days. Experiment 3: Noncannulated chow mice were fasted for 1 and 2 days (n = 2/time). Total cellular RNA from the PP was quantified for MAdCAM-1 mRNA by real-time polymerase chain reaction (PCR). MAdCAM-1 protein was measured by Western blot.

RESULTS

PN rapidly down-regulated MAdCAM-1 gene expression. After 8 hours of PN with lack of enteral feeding, MAdCAM-1 mRNA levels dropped 20% (0.8-fold vs chow, p > .05); 5 days of PN reduced MAd-CAM-1 levels 64% (0.34-fold vs chow, p < .05). PN reduced MAdCAM-1 protein levels by 30% (chow: 329 +/- 14 vs PN: 230 +/- 35, p < .05) after 5 days. Fasting of uncannulated mice decreased MAdCAM-1 mRNA levels by 16% (0.84-fold, p < .05) at day 1 and 30% (0.7-fold, p < .05) by day 2 compared with chow.

CONCLUSIONS

Both PN with lack of enteral feeding and fasting down-regulate MAdCAM-1 mRNA and protein levels in PP. The MAdCAM-1 changes are due to lack of enteral stimulation rather than toxic effects of PN.