Effects of tuberculosis and HIV infection on whole-body protein metabolism during feeding, measured by the [15N]glycine method
Paton, N.I.; Ng, Y-Ming.; Chee, C.B.E.; Persaud, C.; Jackson, A.A.
American Journal of Clinical Nutrition 78(2): 319-325
2003
ISSN/ISBN: 0002-9165 PMID: 12885716 Document Number: 249930
Background: Tuberculosis (TB) and HIV infection are wasting diseases that frequently occur together and have severe consequences on nutritional status. Objective: The objective was to determine the effects of TB and HIV, separately and together, on protein metabolism. Design: This study was conducted at the Communicable Disease Centre of Tan Tock Seng Hospital in Singapore, between October 1999 and June 2000. Protein metabolism was determined in the fed state in 11 healthy control subjects, in 10 patients with HIV infection without TB or other active infection (HIV group), in 10 patients with active TB without HIV infection (TB group), and in 8 patients with HIV infection and active TB (HIVTB group) with the use of oral [15N]glycine and measurement of enrichment in urinary urea and ammonia. Results: Whole-body protein flux and degradation were lower in the HIV group than in the control group (mean flux: 3.53+or-0.40 compared with 4.75+or-0.97 g/kg lean body mass per 12 h; P=0.002). Protein flux, synthesis and degradation were not significantly different between the control group and the TB and HIVTB groups. Net protein balance was strongly anabolic in the control, HIV and TB groups but was neutral in the HIVTB group (P<0.001 for comparison between groups). Conclusions: HIV infection is associated with a significant down-regulation of whole-body protein flux. TB alone is not associated with abnormal protein metabolism, but net anabolism in the fed state is impaired in the HIVTB group.