Association of ITPA gene polymorphisms and the risk of ribavirin-induced anemia in HIV/hepatitis C virus (HCV)-coinfected patients receiving HCV combination therapy.

Polymorphisms of the ITPA gene have been associated with anemia during combination therapy in hepatitis C virus (HCV)-monoinfected patients. Our aim was to confirm this association in HIV/HCV-coinfected patients. In this prospective, observational study, 73 HIV/HCV-coinfected patients treated with pegylated interferon plus ribavirin (RBV) were enrolled. Two single nucleotide polymorphisms within or adjacent to the ITPA gene (rs1127354 and rs7270101) were genotyped. The associations between the ITPA genotype and anemia or treatment outcome were examined. Fifty-nine patients (80.8%) had CC at rs1127354, whereas 14 (19.2%) had a CA/AA ITPA genotype. Percent decreases from baseline hemoglobin level were significantly greater in patients with the CC genotype than in those with the CA/AA genotype at week 4 (P = 0.0003), week 12 (P < 0.0001), and week 36 (P = 0.0102) but not at the end of treatment. RBV dose reduction was more often needed in patients with the CC genotype than in those with the CA/AA genotype (odds ratio [OR] = 11.81; 95% confidence interval [CI] = 1.45 to 256.17; P = 0.0039), as was erythropoietin therapy (OR = 8.28; 95% CI = 1.04 to 371.12; P = 0.0057). Risk factors independently associated with percent hemoglobin nadir decrease were RBV dose reduction (OR = 11.72; 95% CI = 6.82 to 16.63; P < 0.001), baseline hemoglobin (OR = 1.69; 95% CI = 0.23 to 3.15; P = 0.024), and body mass index (OR = -0.7; 95% CI = -1.43 to 0.03; P = 0.061). ITPA polymorphism was not an independent predictor of sustained virological response. Polymorphisms at rs1127354 in the ITPA gene influence hemoglobin levels during combination HCV therapy and the need for RBV dose reduction and erythropoietin use in HIV/HCV-coinfected patients.

Effects of nevirapine and efavirenz on human adipocyte differentiation, gene expression, and release of adipokines and cytokines.

The non-nucleoside reverse transcriptase inhibitors (NNRTIs) nevirapine and efavirenz are drugs of choice for initial antiretroviral treatment for HIV-1 infection. Although NNRTIs have not traditionally been associated with the appearance of adipose alterations, recent data suggest that efavirenz may contribute to adipose tissue alterations in antiretroviral-treated patients, consistent with its ability to impair differentiation of adipocytes in cell cultures. No such effects have been reported for nevirapine, the other most commonly used NNRTI. In this study, we determined the effects of nevirapine on differentiation, gene expression and release of regulatory proteins (adipokines and cytokines) in differentiating human adipocytes, and compared them with those of efavirenz. Efavirenz caused a dose-dependent repression of adipocyte differentiation that was associated with down-regulation of the master adipogenesis regulator genes SREBP-1, PPARγ and C/EBPα, and their target genes encoding lipoprotein lipase, leptin and adiponectin, which are key proteins in adipocyte function. In contrast, nevirapine does not affect adipogenesis and causes a modest but significant coordinate increase in the expression of SREBP-1, PPARγ and C/EBPα and their target genes only at a concentration of 20 µM. Whereas efavirenz caused a significant increase in the release of pro-inflammatory cytokines (interleukin [IL]-8, IL-6, monocyte chemoattractant protein-1), plasminogen activator inhibitor type-1 and hepatocyte growth factor (HGF), nevirapine either had no effect on these factors or decreased their release (IL-6 and HGF). Nevirapine significantly increased adiponectin release, whereas efavirenz strongly repressed it. Moreover, nevirapine inhibited preadipocyte endogenous reverse transcriptase activity, whereas efavirenz did not alter it. It is concluded that, in contrast with the profound anti-adipogenic and pro-inflammatory response elicited by efavirenz, nevirapine does not impair adipogenesis.

Association of thymidylate synthase gene polymorphisms with stavudine triphosphate intracellular levels and lipodystrophy.

The antiviral activity and toxicity of stavudine (d4T) depend on its triphosphate metabolite, stavudine triphosphate (d4T-TP). Therefore, modifications in intracellular levels of d4T-TP may change the toxicity profile of stavudine. d4T-TP intracellular levels in peripheral blood mononuclear cells were determined with a prominence liquid chromatograph connected to a triple-quadruple mass spectrometer. Polymorphisms in the thymidylate synthase (TS), methylenetetrahydrofolate reductase (MTHFR), dihydrofolate reductase (DHFR), reduced folate carrier 1 (RFC1; SLC19A1), and cyclin D1 (CCND1) genes were determined by direct sequencing using an ABI Prism 3100 genetic analyzer or Fluidigm's Biomark system. The Mann-Whitney test, rank analysis of variance (with Bonferroni's adjusted post hoc comparisons), and logistic regression were used for the inferential analyses. Thirty-three stavudine-treated patients were enrolled in this cross-sectional study. d4T-TP intracellular levels were 11.50 fmol/10(6) cells (interquartile range [IQR] = 8.12 to 13.87 fmol/10(6) cells) in patients with a high-expression TS genotype (2/3G, 3C/3G, and 3G/3G), whereas in those with a low-expression TS genotype (2/2, 2/3C, and 3C/3C), they were 21.40 fmol/10(6) cells (IQR = 18.90 to 27.0 fmol/10(6) cells) (P < 0.0001). Polymorphisms in the MTHFR, DHFR, RFC1, and CCND1 genes did not influence the intracellular concentration of d4T-TP. d4T-TP levels were independently associated with the TS genotype (low versus high expression; odds ratio [OR] = 86.22; 95% confidence interval [CI] = 8.48 to nonestimable; P = 0.0023). The low-expression TS genotype was associated with the development of HIV/highly active antiretroviral therapy-associated lypodystrophy syndrome (HALS) (OR = 14.0; 95% CI = 2.09 to 108.0; P = 0.0032). Our preliminary data show that polymorphisms in the thymidylate synthase gene are strongly associated with d4T-TP intracellular levels and with development of HALS.

Differential effects of efavirenz and lopinavir/ritonavir on human adipocyte differentiation, gene expression and release of adipokines and pro-inflammatory cytokines.

In the present study, a comparative assessment of the effects of efavirenz (EFV) and lopinavir/ritonavir (LPV/r; 4:1) on human adipocytes in culture has been performed. Human pre-adipocytes were treated with EFV or LPV/r during or after adipogenic differentiation. Acquisition of adipocyte morphology, expression of gene markers of mitochondrial toxicity, adipogenesis and inflammation, and release of adipokines and cytokines to the medium were measured. Results indicated that EFV and LPV/r impaired adipocyte differentiation in association with a reduction in transcript levels for adipogenic differentiation genes (adiponectin, lipoprotein lipase, leptin) and master regulators of adipogenesis (PPAR, C/EBP). The effects were greater with EFV than LPV/r. Both LPV/r and EFV induced increases in monocytechemoattactant protein-1 (MCP-1) mRNA levels, but the effect was greater with EFV. Similarly, the release of proinflammatory cytokines and other inflammation-related molecules (interleukins 6 and 8, MCP-1, PAI-1) was enhanced to a much higher degree by EFV than by LPV/r. Adiponectin and leptin release by adipocytes was reduced by both drugs, although to a higher extent by EFV. Neither drug affected mitochondrial DNA levels, transcripts encoding mitochondrial proteins or lactate release by adipocytes. In previously differentiated adipocytes, EFV caused a significant reduction in PPARγ and adiponectin expression, whereas LPV/r did not. We conclude that both EFV and LPV/r impair human adipogenesis, reduce adipokine release and increase the expression and release of inflammation-related cytokines, but the overall effects are greater with EFV. These findings may have implications for the pathogenesis of HIV-1-associated lipodystrophy and the development of HIV-1 therapies.