Uridine Metabolism in HIV-1-Infected Patients: Effect of Infection, of Antiretroviral Therapy and of HIV-1/ART-Associated Lipodystrophy Syndrome

Background Uridine has been advocated for the treatment of HIV-1/HAART-associated lipodystrophy (HALS), although its metabolism in HIV-1-infected patients is poorly understood. Methods Plasma uridine concentrations were measured in 35 controls and 221 HIV-1-infected patients and fat uridine in 15 controls and 19 patients. The diagnosis of HALS was performed following the criteria of the Lipodystrophy Severity Grading Scale. Uridine was measured by a binary gradient-elution HPLC method. Analysis of genes encoding uridine metabolizing enzymes in fat was performed with TaqMan RT-PCR. Results Median plasma uridine concentrations for HIV-1-infected patients were 3.80 µmol/l (interquartile range: 1.60), and for controls 4.60 µmol/l (IQR: 1.8) (P = 0.0009). In fat, they were of 6.0 (3.67), and 2.8 (4.65) nmol/mg of protein, respectively (P = 0.0118). Patients with a mixed HALS form had a median plasma uridine level of 4.0 (IC95%: 3.40-4.80) whereas in those with isolated lipoatrophy it was 3.25 (2.55-4.15) µmol/l/l (P = 0.0066). The expression of uridine cytidine kinase and uridine phosphorylase genes was significantly decreased in all groups of patients with respect to controls. A higher expression of the mRNAs for concentrative nucleoside transporters was found in HIV-1-infected patients with respect to healthy controls. Conclusions HIV-1 infection is associated with a decrease in plasma uridine and a shift of uridine to the adipose tissue compartment. Antiretroviral therapy was not associated with plasma uridine concentrations, but pure lipoatrophic HALS was associated with significantly lower plasma uridine concentrations

Differential gene expression indicates that ‘buffalo hump’ is a distinct adipose tissue disturbance in HIV-1-associated lipodystrophy

Objective: To elucidate the molecular basis of the progressive enlargement of dorso-cervical adipose tissue, the so-called 'buffalo hump', that appears in a sub-set of patients with HIV-1/HAART-associated lipodystrophy. Design: Analysis of the expression of marker genes of mitochondrial function, adipogenesis, inflammation and cell proliferation in ten 'buffalo hump' samples and ten subcutaneous fat samples from HIV-1-infected/HAART-treated patients, and in ten healthy controls. Methods: Quantitative real-time polymerase chain reaction analysis of mitochondrial DNA and gene transcripts, and immunoblot for specific proteins. Results: 'Buffalo hump' patients had lower levels of mitochondrial DNA and mitochondrial DNA-encoded transcripts with respect to healthy controls. The uncoupling protein (UCP)-1 gene was expressed only in 'buffalo hump' fat. There were no significant changes in the expression of UCP2, UCP3 or of marker genes of adipogenesis in 'buffalo hump' patients relative to healthy controls. 'Buffalo hump' fat did not show the high expression of tumor necrosis factor-α and β2-microglobulin identified in lipoatrophic subcutaneous fat from patients. The expression of the macrophage marker CD68 was also lower in 'buffalo hump' than in subcutaneous fat from patients. In contrast, 'buffalo hump' showed a higher expression of the cell proliferation marker PCNA. Conclusions: 'Buffalo hump' adipose tissue shows specific disturbances in gene expression with respect to subcutaneous fat from HIV-1-infected/HAART-treated patients. Mitochondrial alterations cannot explain the differential behavior of 'buffalo hump' with respect to adipose depots prone to lipoatrophy. The absence of a local inflammatory status in 'buffalo hump' may explain in part the differential behavior of this adipose tissue

Effects of Switching from Stavudine to Raltegravir on Subcutaneous Adipose Tissue in HIV-Infected Patients with HIV/HAART-Associated Lipodystrophy Syndrome (HALS). A Clinical and Molecular Study

HIV-1/HAART-associated lipodystrophy syndrome (HALS) has been associated with exposure to stavudine (d4T) through mitochondrial dysfunction. We performed a 48-week study to assess the effects of switching from d4T to raltegravir (RAL) on metabolic and fat molecular parameters of patients with HALS. Forty-two patients with HALS and a median exposure to d4T > 7 years were switched to RAL and followed for 48 weeks. Fasting metabolic tests, HIV RNA, CD4 cell count, and fat measured by DEXA were obtained at baseline and week 48. mtDNA and gene transcripts for PPAR gamma, adiponectin, cytochrome b, Cox IV, TNF alpha, MCP-1 and CD68 were assessed in paired subcutaneous fat tissue biopsies. Lipid parameters, fasting glucose, insulin, and HOMA-IR did not change significantly. Whole body fat (P = 0.0027) and limb fat mass (P<0.0001) increased from baseline. Trunk/limb fat ratio (P = 0.0022), fat mass ratio (P = 0.0020), fat mass index (P = 0.0011) and percent leg fat normalized to BMI (P<0.0001) improved after 48 weeks. Relative abundance of mtDNA, expression of PPAR gamma, adiponectin, Cyt b, and MCP-1 genes increased, whereas Cox IV, TNF alpha, and CD68 did not change significantly from baseline. Switching from d4T to RAL in patients with HALS is associated with an increase in limb fat mass and an improvement in markers of adipocyte differentiation and mitochondrial function in SAT