Parenteral nutrition (PN) depresses hepatic albumin synthesis in septic rats

Full text

Serum albumin concentration is frequently used as an indicator of nutritional response in patients receiving PN. The acute-phase response following injury and sepsis is characterised by increased hepatic synthesis of specific secreted proteins while production of albumin is decreased. We have investigated the effect of acute administration of PN on absolute and relative rates of hepatic albumin synthesis during sepsis in vivo. Two groups of male Wistar rats (mean weight 239 g) underwent caecal ligation and puncture (CLP), with a third group as unoperated controls allowed free access to chow and water (ad lib). Between 18 and 24 h later CLP survivors were infused by tail vein with 0.9% NaCl or a PN solution delivering 33% of calculated daily energy and protein requirements. Total hepatic protein synthesis rate (TPS), albumin synthesis rate (TAS) and relative albumin synthesis rate (RAS) were determined with a flooding dose of ³H-phenylalanine and the use of anti-rat albumin antibody to isolate the protein for radioactive counting.

Results

(mean ± SEM) are displayed in the table, with statistical analysis by ANOVA.

Table +P=>0.00001, *P=0.0011 compared with ad lib; #P=0.1, •P=0.0411compared with 0.9% NaCl

We have demonstrated that whereas TPS is increased in sepsis, TAS falls. Provision of PN has no effect on TPS, but significantly further depresses RAS. Reduced hepatic albumin synthesis in sepsis is not reversed by substrate provision, hence changes in serum albumin concentration are unlikely to be a useful monitor of efficacy of PN.