Body Fat Assessment and Adipocytokine Levels in the Lipodystrophy Syndrome in HIV-infected Patients
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Abstract
The lipodystrophy syndrome in HIV-infected patients (LDHIV) is characterized by body morphologic and metabolic changes. This case-control study compared 16 male, HIV-infected, severely lipodystrophic patients on protease inhibitor (PI) therapy to 14 HIV-infected, non-lipodystrophic men not on PI-inclusive HAART. Body fat distribution was assessed using anthropometry, whole-body MRI, and DEXA analysis. Adipocytokines were compared using fasting plasma adiponectin, leptin, and insulin levels. LDHIV patients compared to control subjects had lower peripheral fat with gluteal, suprailiac and triceps skinfolds (all p<0.01, with MRI thigh subcutaneous fat (ThSCF)(mean%±SD, LDHIV 12±5 vs. Controls 22±12 p=0.01) and with DEXA leg fat (%, 12±5 vs. 22±9, p=0.0006). Dorsocervical fat (DCF) accumulation was significantly greater in LDHIV subjects by MRI depth (mm, 47±24 vs. 19±7, p=0.0009) and DEXA head fat (%, 18±3 vs. 16±1, p=0.01), but not significantly by subscapular skinfold p=0.30. In LDHIV patients, abdominal fat was greater by waist circumference (cm, 98±5 vs. 86±9 p=0.0008), nearly significantly greater by MRI Intra-abdominal fat (cm2, 218±90 vs.157±70 p=0.057), and greater by DEXA Trunk percent total fat (%TF, 65±7 vs. 53±8 p=0.0005). In the correlation analysis of LDHIV patients, MRI IAF/ThSCF showed a strong negative relationship to DCF in all three methods r<-0.80, p<0.001, implying a novel split phenotype of either DCF or IAF accumulation. Five combined lipodystrophy parameters were derived, that well delineated the two groups (all p<0.00003). LDHIV patients compared to control subjects also had lower adiponectin levels (3.2±3.1 vs. 5.9±2.9 µg/mL, p=0.01), similar leptin levels (3.5±1.5 vs. 3.0±1.6 ng/mL, p=0.49), and higher insulin levels (20±11/19 vs. 12±6/11 µU/mL, p=0.04). There was a strong negative relationship between adiponectin and insulin levels in the LDHIV group (r=-0.73, p=0.01), but not in control subjects (p=0.33). Conversely, leptin and insulin levels in the control subjects were highly correlated (r=0.86, p<0.0001), but not in LDHIV patients (p=0.82). In conclusion, plasma adiponectin levels are low in patients with LDHIV and may be a better marker than leptin for the hyperinsulinemia of LDHIV. Also, this study has defined consistent methods to quantitatively assess the regional body fat changes and lipodystrophy severity in LDHIV using Anthropometry, DEXA, and MRI.