Preferential loss of omental-mesenteric fat during growth hormone therapy of HIV-associated lipodystrophy

Abstract

. Preferential loss of omental-mesenteric fat during growth hormone therapy of HIV-associated lipodystrophy. J Appl Physiol 94: 2051-2057, 2003; 10.1152/japplphysiol.00845.2002.-Lipodystrophy with increased intra-abdominal fat in human immunodeficiency virus (HIV) infection is common in the era of highly active antiretroviral therapy. It contributes to the metabolic derangements, as it does in non-HIVrelated conditions. Growth hormone administration reduces intra-abdominal fat content. This study compared the relative changes in omental-mesenteric (OMAT) and retroperitoneal adipose tissues (RPAT) during therapy with recombinant human growth hormone (rhGH) in HIVassociated lipodystrophy. Of 30 subjects who began rhGH therapy (6 mg/day), 25 completed 12 wk and 19 completed 24 wk. Fourteen subjects were followed for an additional 12 wk. Volumes of OMAT and RPAT were calculated from total body MRI scans and compared by paired t-tests. Both OMAT and RPAT significantly decreased after 12 and 24 wk of rhGH treatment (P Ͻ 0.001), but the reduction was more pronounced in OMAT than in RPAT (P Ͻ 0.001). Both OMAT and RPAT increased significantly (P Ͻ 0.001) after therapy was discontinued, but OMAT increased significantly more than did RPAT (122 vs. 37%, P Ͻ 0.001). There is preferential loss and regain of OMAT, compared with RPAT, in subjects with HIV-associated lipodystrophy undergoing growth hormone treatment.intra-abdominal adipose tissue; retroperitoneal adipose tissue; visceral adipose tissue; fat redistribution; body composition; human immunodeficiency virus INCREASED INTRA-ABDOMINAL ADIPOSE TISSUE (IAAT) has been linked to metabolic perturbations, especially hyperlipidemia and insulin resistance (21, 23), and reduction of intra-abdominal fat has been shown to improve insulin sensitivity in both animals (2) and humans (17,26). A substantial proportion of human immunodeficiency virus (HIV)-infected individuals on highly active antiretroviral therapy (HAART) develop fat redistribution, or HIV lipodystrophy, which is characterized by increased IAAT and/or depletion of subcutaneous adipose tissue (3-5). It is believed that fat redistribution affects long-term health outcomes by exacerbating the associated metabolic alterations (9, 12), which is a rationale for its treatment. Studies have shown that growth hormone secretion is suppressed in HIV-positive or HIV-negative subjects with increased IAAT (24, 25), and therapy with recombinant human growth hormone (rhGH) reduces IAAT contents (6,16,28). However, the effect of rhGH on relative changes of IAAT subcompartments has not been investigated.The IAAT compartment is complex and includes the retroperitoneal adipose tissue (RPAT) compartment, which is located posterior to the parietal peritoneal membrane, and the omental and mesenteric adipose tissue (OMAT) compartment, which includes the omentum, the serosal layer of the luminal gastrointestinal tract, and the mesentery. The anatomic differences between OMAT and RPAT are quite straightforward. In addition to their different...

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