WHOLE BODY LEUCINE KINETICS DURING ACUTE INFECTION DECREASED BY MALNUTRITION

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study compared leucine kinetics and acute-phase protein and cytokine concentrations in three groups of Malawian children who were fed an isoenergetic, isonitrogenous diet: children with marasmus with (n = 25) and without (n = 17) infection and well-nourished children with infection (n = 13). The hypotheses tested were that whole-body leucine kinetics will be less in marasmic acutely infected children than in well-nourished acutely infected children but greater than in marasmic uninfected children. Children were studied after 24 h of therapy using standard 13C-leucine stable isotope tracer techniques. Well-nourished children with acute infection had greater leucine kinetic rates than did marasmic children with acute infection; nonoxidative leucine disposal was 153 +/- 31 versus 118 +/- 43 [mu]mol leucine kg-1 h-1, leucine derived from whole-body proteolysis was 196 +/- 34 versus 121 +/- 47, and leucine oxidation was 85 +/- 31 versus 45 +/- 13 (p < 0.01 for all comparisons). Leucine kinetic rates were similar in marasmic children with and without acute infection. Well-nourished children with acute infection increased their serum concentration of five of six acute-phase proteins during the first 24 h, whereas marasmic children with infection did not have any increases. The serum concentrations of IL-6 were elevated in well-nourished and marasmic children with infection. These data suggest that the cytokine stimulus for the acute-phase protein kinetic response to acute infection is present in marasmic children but that the acute-phase protein metabolic response is blunted by malnutrition.