Highly active antiretroviral therapy dysregulates proliferation and differentiation of human pre-adipocytes.

Aim: To investigate the mechanism(s) by which potential effects of multi-drug highly-active antiretroviral therapy contributes to lipodystrophy syndrome.

Methods: Preadipocytes from healthy donors were assessed for proliferation and differentiation in the presence of nucleoside reverse transcriptase inhibitors (NRTIs), nonnucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors (PIs) individually and in combination. Effects on proliferation were assessed with a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay and effects on differentiation were assessed from glycerol-3-phosphate dehydrogenase (GP DH) activity and quantitation of Oil Red O staining for intracellular lipid. Data were analyzed with a randomized block ANOVA with post-hoc Fisher's Least Significant Difference test.

Results: Preadipocyte proliferation was inhibited by a combination of NNRTI + NRTI (14% at 48 h, < 0.001) and PI + NRTI (19% at 48 h, < 0.001) with additional suppression when ritonavir (RTV) was added (26% at 48 h). The drug combination of atazanavir (ATV) + RTV + emtricitabine (FTC) + tenofovir (TDF) had the greatest inhibitory effect on proliferation at 48 h. Preadipocyte differentiation was most significantly reduced by the efavirenz + FTC + TDF assessed either by GPDH activity (64%) or lipid accumulation (39%), < 0.001. Combining NRTIs with a PI (ATV + FTC + TDF) significantly suppressed differentiation (GPDH activity reduced 29%, lipid accumulation reduced by 19%, < 0.01). This effect was slightly greater when a boosting amount of RTV was added (ATV + FTC + TDF + RTV, < 0.001).

Conclusion: Although combination antiretroviral therapy is clinically more efficacious than single drug regimens, it also has a much greater inhibitory effect on preadipocyte proliferation and differentiation.