Evidence of nucleoside analogue reverse transcriptase inhibitor--associated genetic and structural defects of mitochondria in adipose tissue of HIV-infected patients

Abstract

To investigate if possible mitochondrial injury can be found in adipose tissue of nucleoside analogue reverse transcriptase inhibitor (NRTI)-treated patients, subcutaneous fat was taken from the buttocks of 24 HIV-positive patients and 8 HIV-negative controls. The content of mitochondrial DNA (mtDNA) was quantified using a Southern blot technique. Fat biopsies were examined by electron microscopy and screened by restriction fragment length polymorphism analysis for the presence of the nt 8344 and 3243 mtDNA point mutations. Age, sex, and body mass index did not differ between the HIV-negative controls, the HIV-positive patients currently treated with NRTIs (NRTI group, n = 19), and the HIV-positive patients without NRTIs (no-NRTI group, n = 5). The mean mtDNA content was 44% lower in the NRTI group compared with the no-NRTI group ( p =.01) but did not differ between the control group and the no-NRTI group. When the HIV-infected patients were stratified to a group with clinical signs of lipoatrophy at the biopsy site (LA group, n = 11) and a group without lipoatrophy (no-LA group, n = 13), the mean mtDNA content in the LA group was 39% lower than that in the no-LA group ( p =.02). No point mutations or deletions were observed. The adipocytes of patients with lipoatrophy contained multiple small lipid vacuoles, and the mitochondria harbored inclusions reminiscent of mtDNA cytopathies. mtDNA depletion and ultrastructural abnormalities of adipocytes suggest a link between mitochondrial damage, the use of NRTIs, and lipoatrophy in HIV-infected patients.