Plasma leptin concentration increases early during highly active antiretroviral therapy for acquired immunodeficiency syndrome, independent of body weight.

Leptin, the protein product of the obese gene (ob), is secreted by adipocytes. Circulating leptin levels correlate with fat mass in humans, including individuals infected with HIV. Leptin serves as an adipostatic hormone, a permissive factor for reproduction and a modulator of immune function. Leptin is a cytokine, and has been demonstrated to enhance CD4 cell proliferation and IL-2 secretion from CD4 cells in vitro. The role of leptin in HIV-positive patients treated with highly active antiretroviral therapy (HAART) has not been well defined. We haveevaluated leptin levels in HIV-infected individualsduringthe early phase of HAART. We measured plasma leptin levels in 15 antiretroviral-naive HIV positive patients at baseline and after 1 and 4 weeks of HAART. After the first week of therapy, mean leptin level and CD4 count were increased compared to baseline, 6.0 vs 7.2 ng/ml (p = 0.004) and 377 vs 432 cells/ul (p = 0.014), respectively. In contrast, mean body mass index (BMI) remained unchanged 27.0 vs 26.8 kg/m2 (p < 0.08). After four weeks of therapy, leptin and BMI values were unchanged compared to baseline, 6.0 vs 5.9 (p < 0.4) and 27.0 vs 26.9 (p < 0.5), respectively, whereas CD4 count continued to increase to 491 cells/ul (p < 0.012 compared to baseline). These data demonstrate an early transient increase in plasma leptin levels in HIV positive patients initiated on HAART, despite a lack of change in BMI. It is unclear if the transient increase in leptin is related to its role as a cytokine, a metabolic regulator, or reproductive factor.

Dermostatin A and B: chromatography, structural and configurational studies using HPLC, CCD, 13C (125 MHz) and 1H (500 MHz) NMR spectroscopy.

HPLC of crude Dermostatin indicated presence of three pairs of components. Hence, attempts were made to purify Dermostatin. Purification of crude Dermostatin has been carried out using column chromatography and counter current distribution methods. Each of these fractions were tested for activity. The major fraction which showed greater activity was taken for the preparation of Dermostatin nona-acetate. Structural characterisation of Dermostatin nona-acetate has been carried out using UV-visible spectroscopy in different solvents to obtain the characteristic spectrum of a carbonyl conjugated hexaene at room temperature. Structural and configurational studies of Dermostatin nona-acetate using 500 MHz 1H NMR and 125 MHz 13C NMR has been used in the assignment of various functional groups in Dermostatin A and B as well as to provide corroboration to the earlier structural elucidation.