Leptin for Abnormal Lipid Kinetics in HIV Lipodystrophy Syndrome
Drug: Human recombinant leptin ("metreleptin")
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
|Official Title:||The Effect of Leptin Therapy on Abnormal Lipid Kinetics in Subjects With HIV Lipodystrophy Syndrome|
- Rate of Total Lipolysis [ Time Frame: 4 months after treatment ]Rate of total lipolysis was measured in plasma samples by mass spectrometry following stable isotope infusions of labeled glycerol and palmitate
- Rate of Net Lipolysis [ Time Frame: 4 months after treatment ]Rate of net lipolysis was measured in plasma samples by mass spectrometry following stable isotope infusions of labeled glycerol and palmitate
- Rates of Fatty Acid Oxidation [ Time Frame: 4 months after treatment ]Rates of fatty acid oxidation were measured in breath samples following stable isotope infusions of 13C-labeled palmitate.
- Fasting Plasma Non-HDL-C [ Time Frame: 4 months after treatment. ]Fasting plasma non-HDL-cholesterol was calculated from measured total cholesterol and HDL cholesterol.
- Glucose Levels After Glucose Challenge [ Time Frame: 4 months after treatment. ]An oral glucose tolerance test was performed. This is not PD/PK in the sense that we are not studying the distribution or clearance of a drug. Rather, we are performing a standard clinical test of glucose tolerance. i.e., a test for diabetes and pre-diabetes. Although multiple time points are used in this test, the outcome is a single value, either a blood glucose level after 2 hours or an area-under-the-curve. In this study we are reporting the area-under-the-curve.
- Insulin Levels After Oral Glucose Challenge. [ Time Frame: 4 months after treatment. ]An oral glucose tolerance test was performed to measure endogenous insulin response. This is not PD/PK in the sense that we are not studying the distribution or clearance of a drug. Rather, we are performing a clinical test of endogenous insulin response to glucose i.e., an endocrine test. Although multiple time points are used in this test, the outcome is a single value, i.e., an area-under-the-curve for insulin.
|Study Start Date:||February 2003|
|Study Completion Date:||October 2011|
|Primary Completion Date:||June 2011 (Final data collection date for primary outcome measure)|
Experimental: human recombinant leptin (metreleptin)
Each subject received 0.02 mg leptin / kg body weight daily by subcutaneous injection for two months, followed by 0.04 mg leptin / kg for two more months.
Drug: Human recombinant leptin ("metreleptin")
Metreleptin was administered at a dose of 0.02 mg / kg body weight for two months, followed by a dose of 0.04 mg / kg for two more months.
Other Name: metreleptin
Placebo Comparator: Placebo injection
Each subject received placebo at a dose of 0.02 mg / kg body weight daily by subcutaneous injection for two months, followed by a dose of 0.04 mg / kg for two more months.
Placebo was administered at a dose of 0.02 mg / kg body weight daily by subcutaneous injection for two months, followed by 0.04 mg / kg for two more months.
The HIV lipodystrophy syndrome (HLS) is characterized by peripheral fat wasting and central obesity, and hyperlipidemia (mainly hypertriglyceridemia), which results in insulin resistance. HLS patients are at high risk for cardiovascular disease, diabetes mellitus and the metabolic syndrome.
The investigators have previously shown that the alterations in lipid metabolism in the so-called mixed form of HLS are due to dysregulation of lipid kinetics at two levels. First, there appears to be an acceleration in lipid kinetics, with higher total and net lipolysis despite higher intra-adipocyte re-esterification. However, the percentage of fatty acid flux being oxidized remains the same, leading to increased hepatic recycling of fatty acids to triglycerides (TG), and export of TG-rich VLDL into the circulation. Second, there is reduced clearance of chylomicron and VLDL-TG from the plasma, resulting in the striking hypertriglyceridemia associated with this syndrome. The investigators propose that these alterations in lipid kinetics account for the phenotypic changes characteristic of this syndrome: increased lipolysis would facilitate peripheral lipoatrophy, increased intra-adipocyte re-esterification (if selective in intrabdominal depots) would contribute to the central obesity, and increased hepatic re-esterification together with impaired VLDL- and chylomicron-TG clearance would lead to hypertriglyceridemia.
Rational treatment of HLS should be targeted at these fundamental kinetic defects. Leptin is in many ways an ideal agent, since it increases fat oxidation, and shifts the ratio of utilization of free fatty acids derived from lipolysis towards oxidation and away from re-esterification, and decreases plasma triglyceride levels. HLS patients with lipoatrophy have low circulating levels of leptin. Moreover, leptin has been shown to be effective in correcting similar defects in fat redistribution and circulating lipids in non-HIV forms of lipodystrophy. Hence, the investigators propose to study (using a blinded, placebo-controlled, dose escalating design) the effect of leptin therapy on lipid kinetics and fat distribution in adult subjects with the lipoatrophic and mixed (peripheral lipoatrophy and central adiposity) forms of HLS. The investigators will use state of the art stable isotope tracer techniques and gas chromatography mass spectrometry (GCMS) to measure whole body lipolysis, lipid oxidation, lipid re-esterification and hepatic lipid recycling.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01511016
|United States, Texas|
|Baylor College of Medicine|
|Houston, Texas, United States, 77030|
|Principal Investigator:||Ashok Balasubramanyam, MD||Baylor College of Medicine|