|
Mitochondrial RNA and DNA alterations in subcutaneous fat tissue of HIV+ subjects with lipoatrophy are linked to antiretroviral therapy and not to HIV infection
Presented by Grace A McComsey, United States.
G.A. McComsey1, D.E. Libutti2, M. O'Riordan3, J.M. Shelton2, N. Storer4, J. Ganz5, J. Jasper5, D. Harrill4, M. Gerschenson2
1Case Western Reserve University, Pediatrics and Medicine, Cleveland, United States, 2John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States, 3Rainbow Babies and Children's Hospital, Cleveland, United States, 4Case Western Reserve University, Cleveland, United States, 5University Hospitals of Cleveland, Cleveland, United States
Background: The effect of antiretroviral therapy (ART) versus HIV itself on the expression of mtRNA and DNA levels in adipose tissue is unclear.
Methods: This is a single site, cross sectional, controlled observational study. Subcutaneous fat was collected from the lower abdomen of 45 HIV+ subjects on HAART with lipoatrophy, 11 HIV+ ART-naïve, and 9 HIV-negative controls. Total DNA was extracted and mtDNA copies/cell were measured by real-time PCR. Total RNA was extracted from fat tissue, reverse transcribed and 3 mt transcripts: NADH dehydrogenase subunit 1(ND1), cytochrome b (CYTB), and NADH dehydrogenase subunit 6 (ND6) genes were quantitated using Taqman probes. MtRNA content was normalized to nuclear-encoded ribosomal L13. We used Wilcoxon rank sum tests and Spearman rank correlation coefficients, as appropriate.
Results: ND1/L13 and CYTB/L13 were significantly reduced in HIV+ lipoatrophic subjects when compared to HIV-infected ART-naïve [3.4 (0.01-16.6) versus 7.2 (3.0-15.4); p=0.017 and 2.5 (0.03-17) versus 4.6 (1.9-22.3); p=0.006]. However, no difference was found between HIV+ naïve and controls (p=0.70 and 0.94, respectively for ND1/L13 and CYTB/L13). ND6/L13 was similar between all groups. DEXA-measured limb fat (grams) and fat mtDNA (copies/cell) were lower in HIV+ lipoatrophy versus HIV+ naïve [4382 (2158-12734) vs. 7662 (2268-18313); p=0.02 and 726 (194-3091) vs. 1372 (532-2721); p=0.03], with no difference found between HIV-naïve and controls (p=0.79). In a multiple regression analysis, only limb fat predicted the three mtRNAs. Levels of mtDNA did not correlate with mtRNAs or with limb fat.
Conclusion: HIV lipoatrophy is associated with mtDNA depletion and decrease in adipose tissue mtRNAs. HIV+ ART-naïve subjects had no mtDNA or mtRNA depletion. This suggests that the mitochondrial toxicity observed in subcutaneous fat tissue of HIV+ subjects with lipoatrophy is mainly driven by ART and not by HIV itself. Also the mtRNA abnormalities, and not mtDNA depletion, may be the driving force behind lipoatrophy in NRTI-treated subjects.
|