Increased mitochondrial DNA content in peripheral blood lymphocytes from HIV-infected patients with lipodystrophy

Abstract

We have evaluated mitochondrial (mt) DNA content in CD4 and CD8 peripheral blood lymphocytes (PBLs) from HIV-infected patients taking highly active antiretroviral therapy (HAART) who display different types of adipose tissue alterations. A cross-sectional study was performed in a total of 23 patients with lipodystrophy (LD): nine patients with fat accumulation, six patients with fat loss, eight patients with combined form, who were compared to 11 individuals infected by HIV without LD (HIV-positive) and 10 seronegative controls (CTRL). PBLs were obtained by standard methods, that is, gradient density centrifugation on Ficoll, and CD4 or CD8 cells were positively isolated by magnetic sorting to eliminate the contamination of platelets. mtDNA content was then measured by an original assay based upon real-time PCR. mtDNA content was significantly increased in CD4 T cells from patients with LD, while no differences were present between CD4 and CD8 cells from HIV-positive and CTRL individuals. Nor were any differences found when comparing LD or HIV-positive patients treated with stavudine or zidovudine, or taking D-drugs or non D-drugs. Patients with fat accumulation had significantly higher mtDNA content compared to HIV-positive and CTRL, this phenomenon regarding both CD4 and CD8 PBLs. Considering all HIV-positive patients (including LD), mtDNA content showed a significant, positive correlation with cholesterolaemia but not with triglyceridaemia and glycaemia. Relatively high mtDNA content in LD patients, as well as the correlation between mtDNA content and cholesterol in all HIV-positive subjects, suggest the involvement of mitochondria in such a pathology. However, further studies are needed to confirm these initial observations and ascertain whether the quantification of mtDNA in PBL is a useful and reliable marker to investigate and monitor HAART-related changes in fat distributio