Body-Composition Changes in the Simian Immunodeficiency Virus-Infected Juvenile Rhesus Macaque

Background. Body-composition changes are common in individuals infected with human immunodeficiency virus. The purpose of the present study was to measure, as a model of wasting in acquired immunodeficiency syndrome (AIDS), longitudinal body-composition changes in macaques infected with simian immunodeficiency virus (SIV). Methods. Twelve juvenile macaques were inoculated with SIVmac239. Immunologic, virologic, somatometric, and dual-energy x-ray-absorptiometry measurements were performed prospectively every 4 weeks for 72 weeks and were compared to measurements taken from 8 uninfected control macaques. Results. During the first 4 weeks, body-fat percentage decreased in the SIV-infected macaques while leantissue percentage increased; during weeks 4–72, these macaques lost a greater percentage of total fat tissue but had more subcutaneous-fat deposition than did the uninfected control macaques. Just prior to death, the SIVinfected macaques that died (n = 7) had a greater loss in body-mass index, abdominal fat, fat tissue, and lean tissue, compared with that in SIV-infected macaques that survived (n = 5). Conclusions. Body-composition changes in SIV-infected juvenile macaques exhibit 3 phases: during acute infection, loss of body weight from fat tissue; a compensation period during which macaques grow, but at a reduced rate; and a terminal phase, during which tissue is lost from all body compartments. The SIV-infected juvenile macaque provides a useful model for the investigation of wasting in AIDS, particularly for pediatric AIDS wasting.