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Journal of Clinical Endocrinology & Metabolism, doi:10.1210/jc.2005-1545
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The Journal of Clinical Endocrinology & Metabolism Vol. 91, No. 7 2605-2611
Copyright © 2006 by The Endocrine Society

Recombinant Methionyl Human Leptin Therapy in Replacement Doses Improves Insulin Resistance and Metabolic Profile in Patients with Lipoatrophy and Metabolic Syndrome Induced by the Highly Active Antiretroviral Therapy

Jennifer H. Lee, Jean L. Chan, Epaminondas Sourlas, Vassilios Raptopoulos and Christos S. Mantzoros

Division of Endocrinology, Diabetes, and Metabolism (J.H.L., J.L.C., C.S.M.), Department of Medicine, and Department of Radiology (V.R.), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215; and Boston University School of Public Health, Health Services Department, and Center for Health Quality, Outcomes, and Economic Research at Veterans Affairs Health Services Research (E.S.), Boston, Massachusetts 02118

Address all correspondence and requests for reprints to: Christos S. Mantzoros, M.D., Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Stoneman 816, Boston, Massachusetts 02215. E-mail: cmantzor{at}bidmc.harvard.edu.


   Abstract
Top
 Abstract
Introduction
 Subjects and Methods
 Results
 Discussion
 References
 
Context: Highly active antiretroviral therapy (HAART) for HIV-1 infection has been associated with a metabolic syndrome characterized by insulin resistance, hyperlipidemia, and redistribution of body fat (lipodystrophy). A subset of patients with predominant lipoatrophy has low levels of the adipocyte-secreted hormone leptin.

Objective: The objective of the study was to assess whether administration of recombinant methionyl human leptin (r-metHuLeptin) improves insulin resistance and other metabolic abnormalities in HIV+ leptin-deficient subjects with HAART-induced lipoatrophy.

Design, Setting, Patients, and Intervention: We conducted a randomized, placebo-controlled, double-blinded, crossover study from 2002 to 2004 in seven HIV+ men with HAART-induced lipoatrophy, serum leptin level less than 3 ng/ml, and fasting triglyceride level greater than 300 mg/dl, who were administered placebo for 2 months before or after administration of r-metHuLeptin at physiological doses for an additional 2 months.

Main Outcome Measures: Insulin resistance, lipid levels, inflammatory markers, body composition, and HIV control were measured.

Results: Compared with placebo, r-metHuLeptin therapy improved fasting insulin levels, insulin resistance (as expressed by the homeostasis model assessment index and an insulin suppression test), and high-density lipoprotein. Body weight and fat mass decreased on r-metHuLeptin, mainly due to a decrease in truncal fat but not peripheral fat or lean body mass. r-metHuLeptin was well tolerated, and HIV control was not adversely affected.

Conclusions: r-metHuLeptin replacement at physiological doses in HIV+ leptin-deficient patients with HAART-induced lipoatrophy improves insulin resistance, high-density lipoprotein, and truncal fat mass. Future larger and more long-term studies in HAART-induced lipoatrophy, including patients with more severe metabolic abnormalities, are warranted to evaluate the physiological and potentially therapeutic role of r-metHuLeptin for this condition and to fully clarify the underlying mechanisms of action.


   Introduction
Top
 Abstract
 Introduction
Subjects and Methods
 Results
 Discussion
 References
 
HIGHLY ACTIVE ANTIRETROVIRAL therapy (HAART) leads to profound suppression of HIV-1 replication but is also associated with the development of a metabolic syndrome characterized by insulin resistance, hyperlipidemia, and body fat redistribution (lipodystrophy) (1). The prevalence of HIV lipodystrophy increases with time of exposure to HAART and is as high as 84% in patients on protease inhibitor-containing HAART regimens (2, 3, 4, 5, 6). On the basis of clinical and imaging criteria, we previously classified HIV lipodystrophy into four subgroups: lipoatrophy (generalized fat depletion), lipohypertrophy (predominant fat accumulation), mixed lipodystrophy, and no lipodystrophy (7, 8). Of HIV patients with 6 months or more of antiretroviral exposure, we found that 19% have predominant lipoatrophy, with higher triglyceride, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) levels, compared with patients with no lipodystrophy, and the highest percentage of visceral fat and the lowest high-density lipoprotein (HDL) levels of the four subgroups (7). Importantly, we found that patients with lipoatrophy have the lowest levels of leptin (7), an adipocyte-secreted hormone that circulates at levels proportional to body fat mass and changes in nutritional status (9, 10). Given the high prevalence of HIV-infected subjects, their prolonged survival due to HAART, and the close association between the insulin resistance syndrome and increased risk of cardiovascular mortality (1, 11, 12), HAART-induced HIV lipodystrophy and metabolic syndrome represents a major health problem for which no approved effective treatment exists.

The HAART-induced metabolic syndrome is likely a multifactorial disorder, with complex interactions of drug, viral, and host-related factors potentially contributing to the development of this syndrome (13). Although the most compelling risk factor is antiretroviral therapy with protease inhibitors and nucleoside reverse transcriptase inhibitors, gender, genetic predisposition, virally mediated mechanisms involving HIV-1 accessory proteins (14, 15), and/or altered hormone (16, 17, 18, 19, 20), and/or inflammatory cytokine (21) levels may also contribute to this syndrome.

Specifically, low levels of leptin may play an important role in the pathogenesis of this metabolic syndrome. Rodents (22) and humans (23) with severe congenital lipoatrophy have leptin deficiency, and administration of exogenous leptin substantially improves their severe insulin resistance, hyperlipidemia, hepatic steatosis, and body composition (22, 23). Because patients with HIV lipoatrophy have low leptin levels (7), we hypothesized that the relative leptin deficiency in these subjects may contribute to their insulin resistance and other metabolic abnormalities. To test this hypothesis, we conducted a proof-of-concept, double-blinded, randomized, placebo-controlled, crossover study involving replacement-dose recombinant methionyl human leptin (r-metHuLeptin) administration in patients with HAART-induced lipoatrophy, relative leptin deficiency, and metabolic syndrome to evaluate whether normalizing leptin levels would improve the metabolic profile in these patients.


   Subjects and Methods
Top
 Abstract
 Introduction
 Subjects and Methods
Results
 Discussion
 References
 
Subjects

Seven men 18 yr old or older, with HIV-1 infection, 6 months or more of cumulative HAART, serum leptin level less than 3 ng/ml, fasting triglyceride level greater than 300 mg/dl, and lipoatrophy as previously defined (8) that developed after HAART initiation, were studied. Exclusion criteria included active infectious diseases other than HIV infection, renal insufficiency, liver disease (aspartate aminotransferase or alanine aminotransferase ≥ 3 times normal), malignancy, diabetes before alanine HAART initiation, thyroid disease, hypercortisolism, and active alcohol or drug abuse.

Study design

The study protocol was approved by the Institutional Review Board of the Beth Israel Deaconess Medical Center, and all subjects provided written informed consent to participate. Ten of 25 screened subjects met the study eligibility criteria. Seven of the 10 eligible subjects entered a 1-month run-in phase, during which time they maintained a stable diet and exercise regimen. The remaining three eligible subjects expressed their inability to comply with the study requirements, i.e. with regard to travel to the study center for multiple visits. Six of the seven subjects studied were on protease inhibitors [three on Kaletra (lopinavir + ritonavir), two on indinavir, two on ritonavir (without lopinavir), one on saquinavir, and one on amprenavir]. Six of the seven subjects were on nucleoside reverse transcriptase inhibitors (five on stavudine, three on lamivudine, two on abacavir, and one on didanosine). Two of the seven subjects were also on nonnucleoside reverse transcriptase inhibitors (one on nevirapine and one on efavirenz). None of the subjects were on insulin sensitizers or lipid-lowering medications, except one subject who was on fish oil, which was continued at the same dose throughout the study.

Subjects with triglyceride level greater than 300 mg/dl but less than 1000 mg/dl at the end of the 1-month run-in phase were randomized by an independent research pharmacist, in a double-blind fashion, to initial treatment with either r-metHuLeptin or matching placebo at a dose of 0.04 mg/kg·d divided into two equal doses, which were self-administered by sc injection at 0800 and 2000 h daily for 2 months. They then discontinued treatment for a 1-month washout period before being crossed over to receive the other treatment for 2 months, followed by another 1-month washout period.

Subjects had the following baseline tests at the beginning of each r-metHuLeptin or placebo treatment period: hormone and other metabolic measurements [leptin, insulin, glucose, free fatty acids (FFAs), adiponectin], with HOMA-IR calculated as [(insulin [microinternational units per milliliter]) x (glucose [millimoles per liter])]/22.5, lipid measurements (total cholesterol, triglycerides, HDL, low-density lipoprotein (LDL), apolipoprotein A1 and B, lipoprotein particle size), thrombotic factors (factor VIII, fibrinogen), inflammatory markers [TNF{alpha}, IL-6, C-reactive protein (CRP)], and HIV markers (CD4 count, CD8 count, HIV viral load); body composition analysis with anthropometry and dual-energy x-ray absorptiometry (DEXA); and abdominal computed tomography (CT) for measurement of hepatic and im lipid content. Because this is the first r-metHuLeptin administration study in this population, a pharmacokinetic profile of leptin levels at time 0 (baseline), +10 min, +30 min, +1 h, +2 h, +3 h, +4 h, +5 h, +6 h, and +12 h was obtained after the first administered dose of study medication at the beginning of each treatment arm.

Subjects were advised to keep their HAART regimen (documented by review at each study visit), exercise regimen, and diet stable (monitored through log books) and returned every 2 wk during treatment for measurement of leptin, insulin, glucose, lipid levels, and liver function tests, with anthropometry measurements at 4 wk. At the end of each 2-month treatment period, subjects had repeat measurement of all the baseline tests as outlined above. In addition, they had a standard insulin suppression test (Galvin’s Index), which provides an estimation of insulin sensitivity over a 3-h period by assessing the decline in glucose over a 40-min period divided by the area under the insulin curve (24) and captures approximately 90% of information on insulin sensitivity (25).

The primary outcome was to study the effect of r-metHuLeptin replacement on insulin resistance, as expressed primarily by fasting insulin but also HOMA-IR and Galvin’s Index. Secondarily, we assessed lipid measurements, body composition, thrombotic factors, inflammatory markers, and measures of HIV control and immune function, as described above.

Assessments

Standard techniques were used to measure leptin (Linco Research, St. Charles, MO), adiponectin (Linco Research), insulin (Diagnostic Products Corp., Los Angeles, CA), TNF{alpha} (R&D Systems, Minneapolis, MN), IL-6 (R&D Systems), CRP (Diagnostic Systems Laboratory, Webster, TX), FFAs (Wako Chemicals, Neuss, Germany), lipoprotein particle size (Liposcience, Raleigh NC), and apolipoprotein A1 and B (Roche, Stockholm, Sweden). Other laboratory testing was performed at the BIDMC clinical laboratory. Body composition was measured using DEXA (QDR-4500; Hologic, Bedford, MA).

An eight-row multidetector CT scanner (LightSpeed Plus; GE Medical Systems, Milwaukee, WI) was used to assess liver volume and quantitate hepatic and im lipid content. Spiral CT was used to scan the liver and upper abdomen, and approximately 36 5-mm-thick slices were obtained in 3 sec. Using commercially available software (GE Advantage Windows, GE Medical Systems), the liver was segmented using a semiautomated technique that provides high accuracy in assessing liver volume (26). Normal liver volume for a male is considered 22.9 ml/kg, or 1603 ml for a 70-kg person. The mean attenuation of the liver volume in Hounsfield units (HU) was then measured, and an attenuation of 60–70 HU was considered normal (27). Considering fat attenuation at –100 HU, percent liver fat was then calculated using the following formula: [([60 – mean liver attenuation]/160) x 100]. Muscle attenuation over the left and right psoas muscles at the level of L4 was measured to assess im lipid content, which was calculated as follows: [([40 – mean muscle attenuation]/140) x 100]. Normal muscle attenuation is considered to be 40 HU (28).

Abdominal fat mass was measured using DEXA because its data reflect a larger area and assessment of truncal fat over the entire abdomen, not only from one slice. We previously reported a strong correlation between truncal fat, a marker of central adiposity obtained by DEXA, and waist circumference, a surrogate marker for central adiposity obtained at one level (Pearson coefficient = 0.90, P < 0.001) (29). Abdominal fat mass was also assessed by CT scanning to determine whether changes in abdominal fat represented changes in visceral fat and/or sc fat.

Statistical analysis

SAS (version 8.02, SAS Institute, Cary, NC) and SPSS (version 11.5, SPSS Inc., Chicago, IL) were used for statistical analysis, and P < 0.05 (two-tailed) was considered statistically significant for all analyses. Data are expressed as mean ± SEM. We used nonparametric Wilcoxon tests to compare change under r-metHuLeptin vs. placebo, with Wilcoxon’s rank sum (independent-samples tests) as primary analysis (intention-to-treat analysis, n = 7 receiving r-metHuLeptin and n = 7 completing placebo treatment), and Wilcoxon’s signed rank (paired tests) as secondary analysis (on-treatment analysis, n = 5 completing both r-metHuLeptin and placebo treatments). We also performed multivariate analysis by fitting a mixed model with a random subject component permitting correlation within patients and nonconstant variability, and controlling for treatment sequence, with and without additional adjustment for changes in visceral fat mass. To assess how quickly and stably the treatment improves insulin resistance and hyperlipidemia (repeated-measures analysis), we used the generalized estimating equation procedure, specifying a within-subject correlation structure and testing for significant differences in treatment effects between initiation of treatment and each of the four subsequent time points during treatment. We present both adjusted and unadjusted models herein. Using an alpha level of 0.05, our study had 90% power to detect a difference in means between the two groups that is equal to or larger than 2.2 SE of the mean of the respective variable (and 80% power to detect a difference in means between the two groups that is equal to or larger than 1.9 SE of the respective mean).


   Results
Top
 Abstract
 Introduction
 Subjects and Methods
 Results
Discussion
 References
 
Subjects had the following baseline characteristics at screening: age, 45.8 ± 2.00 yr; body mass index (BMI), 21.8 ± 0.80 kg/m2; fasting leptin, 1.34 ± 0.20 ng/ml; triglycerides, 530.0 ± 53.8 mg/dl; insulin, 11.5 ± 2.70 µIU/ml; glucose, 81.1 ± 6.70 mg/dl; hemoglobin A1c, 5.10 ± 0.30%; CD4 count, 454 ± 94 cells/µl; and HIV viral load, 24,524 ± 13,693 copies/ml. The subjects maintained a stable HAART regimen throughout the study.

Seven subjects completed at least one arm of the study; five subjects completed both r-metHuLeptin and placebo treatments. Two subjects were withdrawn, after 11/2 and 2 months of r-metHuLeptin, respectively, because their triglyceride levels were greater than the 1000 mg/dl level specified in the protocol. The two withdrawn subjects had triglyceride levels greater than 1000 mg/dl intermittently before starting the study. The subject who was withdrawn after 11/2 months of r-metHuLeptin therapy was on two nucleoside reverse transcriptase inhibitors and a protease inhibitor. The subject who was withdrawn after 2 months of therapy was on two protease inhibitors as well as fish oil, which was continued at the same dose throughout the study. After leaving the study, the two withdrawn subjects were started on lipid-lowering agents by their primary care physicians with improvement in their triglyceride levels.

The pharmacokinetic profile performed at the beginning of the r-metHuLeptin arm revealed leptin levels of 0.88 ± 0.49 ng/ml at baseline, 6.90 ± 1.00 ng/ml at 10 min, a peak of 16.0 ± 1.27 ng/ml at 4 h, and 2.53 ± 0.84 ng/ml at 12 h (Fig. 1Go). There were no significant differences in any variables at the beginning of the two treatment periods, indicating that the washout was successful. By univariate analysis, there were also no significant differences between the r-metHuLeptin and placebo arms with regard to intake of total kilocalories, protein, carbohydrates, total fat, and saturated fat. However, with multivariate analysis accounting for random subject effect and treatment order, there was a trend toward a significant decrease in total kilocalories (P = 0.06).


Figure 1
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  		FIG. 1. Pharmacokinetic profile of r-metHuLeptin.

 
During r-metHuLeptin therapy, body weight, BMI, and percentage and total fat mass declined, mainly due to a decrease in truncal but not peripheral fat (Table 1Go). Specifically, there was a 0.72% relative decrease in percent body fat, adjusting for the increased percent body fat on placebo (or 5.7% relative decrease). Similarly, total fat mass decreased by 0.94 kg (or 10.1%), after adjusting for the increase in fat mass on placebo. Moreover, r-metHuLeptin therapy resulted in a decrease in trunk fat by 0.86 kg (or 14.6%), after adjusting for the increase on placebo. These differences remained statistically significant after multivariate analysis adjusting for random subject effect and treatment order. Therefore, 91% of the decline in total fat mass (0.94 kg) was due to a decrease in trunk fat (0.86 kg).


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  		TABLE 1. Major study outcomes (mean ± SE) before and after treatment with r-metHuLeptin or placebo

 
Subcutaneous fat as assessed by CT increased from 18.3 ± 6.02 to 28.4 ± 8.58 cm2 on leptin therapy and decreased from 24.8 ± 10.3 to 21.4 ± 7.83 cm2 on placebo [P = 0.10 by independent samples test (n = 7), or simple univariate analysis]. Visceral fat as assessed by CT decreased from 183.4 ± 49.6 to 172.7 ± 48.0 cm2 on leptin therapy, and decreased from 167.6 ± 57.8 to 155.0 ± 54.0 cm2 on placebo (P = 1.0). The ratio of sc fat to visceral fat increased from 15.3 ± 6.0 to 20.1 ± 4.7% on leptin therapy and remained unchanged from 17.0 ± 6.2 to 17.4 ± 6.8% on placebo (P = 0.43).

Fasting insulin levels, HOMA-IR (Table 1Go), and Galvin’s Index (P = 0.06) (measures of insulin resistance) declined, whereas HDL levels increased, with r-metHuLeptin. Specifically, insulin decreased by 5 IU/ml, or 30% during r-metHuLeptin treatment, and after controlling for the increase on placebo, there was a relative decrease in insulin of 11.9 IU/ml, or 71.9%. Furthermore, by analysis of treatment-by-period interaction, the effect of r-metHuLeptin on insulin levels became statistically significant after 6 wk of therapy (P = 0.02) (Fig. 2Go). Similarly, HOMA-IR decreased by 1.06, or 29.6%, in the r-metHuLeptin arm, and after adjusting for placebo, there was a relative decrease in HOMA-IR of 2.67, or 74.6%, which became statistically significant after 4 wk of therapy (P = 0.02) (Fig. 2Go). Multivariate analysis adjusting for random subject effect and treatment order, with and without additional adjustment for change in visceral fat, did not materially alter the findings of the univariate models, with the exception of HDL and IL-6.


Figure 2
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  		FIG. 2. Effect of r-metHuLeptin or placebo on insulin (A) and HOMA-IR (B). Treatment-by-period interaction: *, P < 0.05; **, P < 0.01.

 
HDL increased by 3.49 mg/dl, or 11.1%, in the r-metHuLeptin arm, with a relative increase of 6.81 mg/dl, or 21.6% after adjusting for the decrease on placebo, which became statistically significant after 8 wk of therapy (P = 0.002) (data not shown). The difference remained borderline significant after adjusting for random subject effect and treatment order (P = 0.05). However, there was no significant difference in HDL after additionally adjusting for change in visceral fat (P = 0.11, Table 1Go), indicating that the effect of leptin on increasing HDL levels is at least in part mediated by changes in visceral fat mass. In contrast, multivariate analysis adjusting for random subject effect, treatment order, and sc to visceral fat ratio (instead of visceral fat alone) remained statistically significant (P = 0.03).

IL-6 decreased by 1.91 pg/ml, or 53.7%, in the r-metHuLeptin arm, but after adjusting for a decrease on placebo, there was a relative decrease of 1.41 pg/ml, or 39.6%. However, there was no significant difference in IL-6 levels between the two groups after multivariate analysis adjusting for random subject effect and treatment order (P = 0.17), or after additional adjustment for change in visceral fat (P = 0.24, Table 1Go), indicating that there is no significant effect of leptin on decreasing IL-6.

There were no significant changes in percentage liver fat, liver volume, triglycerides, LDL, FFAs, TNF{alpha}, CRP, CD4+ lymphocytes, HIV viral load (Table 1Go), CD8+ lymphocytes, adiponectin, im lipid content, apolipoprotein levels, lipoprotein particle size, factor VIII, fibrinogen, or blood pressure between the two treatment arms (data not shown). No effect of treatment order was observed, and no subjects had side effects related to r-metHuLeptin treatment.


   Discussion
Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
References
 
HAART suppresses HIV-1 replication and thus improves morbidity and mortality in HIV+ patients but can result in a prevalent metabolic syndrome characterized by lipodystrophy, insulin resistance, and hyperlipidemia, leading to increased cardiovascular risk (1). This randomized, placebo-controlled study demonstrates that short-term r-metHuLeptin replacement therapy in HIV+ patients with relative leptin deficiency, lipoatrophy, and mild insulin resistance (including moderate hypertriglyceridemia, without pronounced intrahepatic or im fat accumulation) decreases central fat mass and improves insulin resistance, without adversely affecting HIV control. In contrast, the metabolic profile of patients on placebo tended to deteriorate over this time frame.

Uncontrolled studies of chronic r-metHuLeptin administration in humans with severe congenital non-HIV lipodystrophy and leptin deficiency have shown dramatic improvements in insulin resistance, hyperlipidemia, and hepatic steatosis (23, 30, 31). The more modest improvement with r-metHuLeptin observed herein, compared with that observed in congenital lipodystrophy, is likely related primarily to the milder degree of leptin deficiency, as well as the shorter duration of leptin deficiency, and/or the presence of less severe metabolic abnormalities (by design). Whereas the HAART-induced lipoatrophy and metabolic syndrome can range from mild metabolic abnormalities, such as in the subjects studied herein, to more severe manifestations, the degree of metabolic derangements is generally not as pronounced as in congenital severe lipodystrophy. Furthermore, given that HAART-induced lipoatrophy and metabolic syndrome is considerably more prevalent than congenital severe lipodystrophy, our findings are applicable to a much larger population.

It has been proposed that leptin may improve insulin resistance through several mechanisms, i.e. activating insulin signaling pathways including skeletal muscle phosphatidylinositol 3-kinase and AMP-activated protein kinase (32), decreasing intrahepatic and intramyocellular fat (33), decreasing caloric intake (30, 34), and/or decreasing body weight and fat mass (30). In contrast to the studies of leptin replacement for 4 months in patients with severe non-HIV lipodystrophy (30), we did not find a significant decrease in appetite, which may be due to the lower r-metHuLeptin dose used herein, and found only a trend toward decreased caloric intake after multivariate analysis. However, there was a significant decrease in body weight, BMI, percent body fat, and total fat mass, mainly due to decreased truncal fat.

Transgenic mouse models of lipoatrophy have provided further understanding about leptin’s role in the insulin resistance and metabolic profile associated with lipoatrophy. These models are characterized by marked insulin resistance, hyperlipidemia, and decreased expression and/or activation of leptin, adiponectin, and peroxisomal proliferator-activated receptor (PPAR)-{gamma} (35, 36, 37, 38), a nuclear factor that plays essential roles in adipogenesis, adiponectin production, and glucose and lipid metabolism (39, 40). In lipoatrophic mice, transplantation of ob/ob (leptin-deficient) adipose tissue had no effect on the metabolic phenotype, whereas leptin infusion (without adipose tissue transplantation) improved the metabolic status of the mice, thereby supporting the concept that leptin deficiency plays a major role in the metabolic derangements of lipoatrophy (38). Furthermore, leptin or adiponectin treatment alone improved insulin resistance partially, whereas the combination of the two completely reversed insulin resistance (37).

A critical step in the development of the HAART-induced metabolic syndrome is the inhibition of adipocyte expression of PPAR-{gamma} (41, 42). Because PPAR-{gamma} is preferentially expressed in peripheral adipose tissue (43), inhibition of PPAR-{gamma} expression by protease inhibitors would result in apoptosis and impaired differentiation of peripheral adipocytes, thus contributing to the fat redistribution, abnormal adipokine levels, and metabolic changes associated with the HAART-induced metabolic syndrome. We did not observe any significant change in adiponectin levels with r-metHuLeptin therapy, consistent with our previous data showing that leptin administration at physiological or pharmacological doses does not alter serum adiponectin levels in normal subjects (29). However, thiazolidinediones, PPAR-{gamma} agonists that increase adiponectin levels, have recently been shown to improve insulin sensitivity in HIV lipoatrophic humans (44, 45). Whether combination treatment with r-metHuLeptin and a medication that increases adiponectin levels, such as a thiazolidinedione, has a synergistic effect to improve insulin resistance and metabolic abnormalities in humans remains to be studied.

In summary, this study focused on a prevalent syndrome of lipoatrophy and mild insulin resistance, was of adequate power, found statistically significant results, and establishes the proof-of-concept for r-metHuLeptin replacement in HAART-induced lipoatrophy and metabolic syndrome. Strengths of this interventional study include the randomized, placebo-controlled design that reduces bias and confounding, the crossover methodology that increases study power, and the intensive evaluation of multiple parameters that more fully elucidates the role of leptin in this syndrome. Larger studies of patients with more severe HAART-induced lipoatrophy and metabolic abnormalities, using high-physiological and possibly pharmacological r-metHuLeptin doses over longer periods of time, are warranted to further evaluate the physiological and potentially therapeutic role of r-metHuLeptin in this disorder and clarify the underlying mechanisms of action.


   Acknowledgments
 
We are grateful to the nurses, technicians, and nutritionists at the Beth Israel Deaconess Medical Center General Clinical Research Center and Core Lab for their assistance in the conduct of the study.


   Footnotes
 
This work was supported by National Institutes of Health Grant MO1-RR01032; National Institute of Diabetes and Digestive and Kidney Diseases Grant R01-58785; National Center for Research Resources Grants K23 RR-018860 and 5T32DK07516-18; an Amgen, Inc. grant; and an Eli Lilly and Co. fellowship award. Amgen, Inc. supplied r-metHuLeptin for this study and approved the design of the study but had no role in the study design; conduct of the study; collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.

First Published Online April 24, 2006

Abbreviations: BMI, Body mass index; CRP, C-reactive protein; CT, computed tomography; DEXA, dual-energy x-ray absorptiometry; FFA, free fatty acid; HAART, highly active antiretroviral therapy; HDL, high-density lipoprotein; HOMA-IR, homeostasis model assessment of insulin resistance; HU, Hounsfield unit; LDL, low-density lipoprotein; PPAR, peroxisomal proliferator-activated receptor; r-metHuLeptin, recombinant methionyl human leptin.

Received July 12, 2005.

Accepted April 17, 2006.


   References
Top
 Abstract
 Introduction
 Subjects and Methods
 Results
 Discussion
 References
 

  1. Grinspoon S, Carr A 2005 Cardiovascular risk and body-fat abnormalities in HIV-infected adults. N Engl J Med 352:48–62[Free Full Text]
  2. Tsiodras S, Mantzoros C, Hammer S, Samore M 2000 Effects of protease inhibitors on hyperglycemia, hyperlipidemia, and lipodystrophy: a 5-year cohort study. Arch Intern Med 160:2050–2056[Abstract/Free Full Text]
  3. Carr A, Samaras K, Burton S, Law M, Freund J, Chisholm DJ, Cooper DA 1998 A syndrome of peripheral lipodystrophy, hyperlipidaemia and insulin resistance in patients receiving HIV protease inhibitors. AIDS 12:F51–F58
  4. Carr A, Samaras K, Thorisdottir A, Kaufmann GR, Chisholm DJ, Cooper DA 1999 Diagnosis, prediction, and natural course of HIV-1 protease-inhibitor-associated lipodystrophy, hyperlipidaemia, and diabetes mellitus: a cohort study. Lancet 353:2093–2099[CrossRef][Medline]
  5. Reus S, Arroyo E, Boix V, Portilla J 2000 [Lipodystrophy and hyperglycemia produced by protease inhibitors]. An Med Interna 17:123–126[Medline]
  6. Martinez E, Mocroft A, Garcia-Viejo MA, Perez-Cuevas JB, Blanco JL, Mallolas J, Bianchi L, Conget I, Blanch J, Phillips A, Gatell JM 2001 Risk of lipodystrophy in HIV-1-infected patients treated with protease inhibitors: a prospective cohort study. Lancet 357:592–598[CrossRef][Medline]
  7. Nagy GS, Tsiodras S, Martin LD, Avihingsanon A, Gavrila A, Hsu WC, Karchmer AW, Mantzoros CS 2003 Human immunodeficiency virus type 1-related lipoatrophy and lipohypertrophy are associated with serum concentrations of leptin. Clin Infect Dis 36:795–802[CrossRef][Medline]
  8. Addy CL, Gavrila A, Tsiodras S, Brodovicz K, Karchmer AW, Mantzoros CS 2003 Hypoadiponectinemia is associated with insulin resistance, hypertriglyceridemia, and fat redistribution in human immunodeficiency virus-infected patients treated with highly active antiretroviral therapy. J Clin Endocrinol Metab 88:627–636[Abstract/Free Full Text]
  9. Havel PJ 2004 Update on adipocyte hormones: regulation of energy balance and carbohydrate/lipid metabolism. Diabetes 53(Suppl 1):S143–S151
  10. Kershaw EE, Flier JS 2004 Adipose tissue as an endocrine organ. J Clin Endocrinol Metab 89:2548–2556[Abstract/Free Full Text]
  11. Haffner SM, D’Agostino Jr R, Mykkanen L, Tracy R, Howard B, Rewers M, Selby J, Savage PJ, Saad MF 1999 Insulin sensitivity in subjects with type 2 diabetes. Relationship to cardiovascular risk factors: the Insulin Resistance Atherosclerosis Study. Diabetes Care 22:562–568[Abstract]
  12. Isomaa B, Almgren P, Tuomi T, Forsen B, Lahti K, Nissen M, Taskinen MR, Groop L 2001 Cardiovascular morbidity and mortality associated with the metabolic syndrome. Diabetes Care 24:683–689[Abstract/Free Full Text]
  13. Leow MK, Addy CL, Mantzoros CS 2003 Clinical review 159: human immunodeficiency virus/highly active antiretroviral therapy-associated metabolic syndrome: clinical presentation, pathophysiology, and therapeutic strategies. J Clin Endocrinol Metab 88:1961–1976[Free Full Text]
  14. Kino T, Gragerov A, Kopp JB, Stauber RH, Pavlakis GN, Chrousos GP 1999 The HIV-1 virion-associated protein vpr is a coactivator of the human glucocorticoid receptor. J Exp Med 189:51–62[Abstract/Free Full Text]
  15. Kino T, Chrousos GP 2004 Human immunodeficiency virus type 1 accessory protein Vpr: a causative agent of the AIDS-related insulin resistance/lipodystrophy syndrome? Ann NY Acad Sci 1024:153–167[Abstract/Free Full Text]
  16. Rietschel P, Hadigan C, Corcoran C, Stanley T, Neubauer G, Gertner J, Grinspoon S 2001 Assessment of growth hormone dynamics in human immunodeficiency virus-related lipodystrophy. J Clin Endocrinol Metab 86:504–510[Abstract/Free Full Text]
  17. Engelson ES, Glesby MJ, Mendez D, Albu JB, Wang J, Heymsfield SB, Kotler DP 2002 Effect of recombinant human growth hormone in the treatment of visceral fat accumulation in HIV infection. J Acquir Immune Defic Syndr 30:379–391[Medline]
  18. Schwarz JM, Mulligan K, Lee J, Lo JC, Wen M, Noor MA, Grunfeld C, Schambelan M 2002 Effects of recombinant human growth hormone on hepatic lipid and carbohydrate metabolism in HIV-infected patients with fat accumulation. J Clin Endocrinol Metab 87:942
  19. Hadigan C, Corcoran C, Stanley T, Piecuch S, Klibanski A, Grinspoon S 2000 Fasting hyperinsulinemia in human immunodeficiency virus-infected men: relationship to body composition, gonadal function, and protease inhibitor use. J Clin Endocrinol Metab 85:35–41[Abstract/Free Full Text]
  20. Hadigan C, Corcoran C, Piecuch S, Rodriguez W, Grinspoon S 2000 Hyperandrogenemia in human immunodeficiency virus-infected women with the lipodystrophy syndrome. J Clin Endocrinol Metab 85:3544–3550[Abstract/Free Full Text]
  21. Imami N, Antonopoulos C, Hardy GA, Gazzard B, Gotch FM 1999 Assessment of type 1 and type 2 cytokines in HIV type 1-infected individuals: impact of highly active antiretroviral therapy. AIDS Res Hum Retroviruses 15:1499–1508[CrossRef][Medline]
  22. Shimomura I, Hammer RE, Ikemoto S, Brown MS, Goldstein JL 1999 Leptin reverses insulin resistance and diabetes mellitus in mice with congenital lipodystrophy. Nature 401:73–76[CrossRef][Medline]
  23. Oral EA, Simha V, Ruiz E, Andewelt A, Premkumar A, Snell P, Wagner AJ, DePaoli AM, Reitman ML, Taylor SI, Gorden P, Garg A 2002 Leptin-replacement therapy for lipodystrophy. N Engl J Med 346:570–578[Abstract/Free Full Text]
  24. Galvin P, Ward G, Walters J, Pestell R, Koschmann M, Vaag A, Martin I, Best JD, Alford F 1992 A simple method for quantitation of insulin sensitivity and insulin release from an intravenous glucose tolerance test. Diabet Med 9:921–928[Medline]
  25. Howard G, O’Leary DH, Zaccaro D, Haffner S, Rewers M, Hamman R, Selby JV, Saad MF, Savage P, Bergman R 1996 Insulin sensitivity and atherosclerosis. The Insulin Resistance Atherosclerosis Study (IRAS) Investigators. Circulation 93:1809–1817[Abstract/Free Full Text]
  26. Kamel IR, Kruskal JB, Pomfret EA, Keogan MT, Warmbrand G, Raptopoulos V 2001 Impact of multidetector CT on donor selection and surgical planning before living adult right lobe liver transplantation. AJR Am J Roentgenol 176:193–200[Abstract/Free Full Text]
  27. Raptopoulos V, Karellas A, Bernstein J, Reale FR, Constantinou C, Zawacki JK 1991 Value of dual-energy CT in differentiating focal fatty infiltration of the liver from low-density masses. AJR Am J Roentgenol 157:721–725[Abstract/Free Full Text]
  28. O’Doherty DS, Schellinger D, Raptopoulos V 1977 Computed tomographic patterns of pseudohypertrophic muscular dystrophy: preliminary results. J Comput Assist Tomogr 1:482–486[Medline]
  29. Gavrila A, Chan JL, Yiannakouris N, Kontogianni M, Miller LC, Orlova C, Mantzoros CS 2003 Serum adiponectin levels are inversely associated with overall and central fat distribution but are not directly regulated by acute fasting or leptin administration in humans: cross-sectional and interventional studies. J Clin Endocrinol Metab 88:4823–4831[Abstract/Free Full Text]
  30. Moran SA, Patten N, Young JR, Cochran E, Sebring N, Reynolds J, Premkumar A, DePaoli AM, Skarulis MC, Oral EA, Gorden P 2004 Changes in body composition in patients with severe lipodystrophy after leptin replacement therapy. Metabolism 53:513–519[CrossRef][Medline]
  31. Javor ED, Ghany MG, Cochran EK, Oral EA, DePaoli AM, Premkumar A, Kleiner DE, Gorden P 2005 Leptin reverses nonalcoholic steatohepatitis in patients with severe lipodystrophy. Hepatology 41:753–760[CrossRef][Medline]
  32. Kim YB, Uotani S, Pierroz DD, Flier JS, Kahn BB 2000 In vivo administration of leptin activates signal transduction directly in insulin-sensitive tissues: overlapping but distinct pathways from insulin. Endocrinology 141:2328–2339[Abstract/Free Full Text]
  33. Petersen KF, Oral EA, Dufour S, Befroy D, Ariyan C, Yu C, Cline GW, DePaoli AM, Taylor SI, Gorden P, Shulman GI 2002 Leptin reverses insulin resistance and hepatic steatosis in patients with severe lipodystrophy. J Clin Invest 109:1345–1350[CrossRef][Medline]
  34. McDuffie JR, Riggs PA, Calis KA, Freedman RJ, Oral EA, DePaoli AM, Yanovski JA 2004 Effects of exogenous leptin on satiety and satiation in patients with lipodystrophy and leptin insufficiency. J Clin Endocrinol Metab 89:4258–4263[Abstract/Free Full Text]
  35. Shimomura I, Hammer RE, Richardson JA, Ikemoto S, Bashmakov Y, Goldstein JL, Brown MS 1998 Insulin resistance and diabetes mellitus in transgenic mice expressing nuclear SREBP-1c in adipose tissue: model for congenital generalized lipodystrophy. Genes Dev 12:3182–3194[Abstract/Free Full Text]
  36. Moitra J, Mason MM, Olive M, Krylov D, Gavrilova O, Marcus-Samuels B, Feigenbaum L, Lee E, Aoyama T, Eckhaus M, Reitman ML, Vinson C 1998 Life without white fat: a transgenic mouse. Genes Dev 12:3168–3181[Abstract/Free Full Text]
  37. Yamauchi T, Kamon J, Waki H, Terauchi Y, Kubota N, Hara K, Mori Y, Ide T, Murakami K, Tsuboyama-Kasaoka N, Ezaki O, Akanuma Y, Gavrilova O, Vinson C, Reitman ML, Kagechika H, Shudo K, Yoda M, Nakano Y, Tobe K, Nagai R, Kimura S, Tomita M, Froguel P, Kadowaki T 2001 The fat-derived hormone adiponectin reverses insulin resistance associated with both lipoatrophy and obesity. Nat Med 7:941–946[CrossRef][Medline]
  38. Colombo C, Cutson JJ, Yamauchi T, Vinson C, Kadowaki T, Gavrilova O, Reitman ML 2002 Transplantation of adipose tissue lacking leptin is unable to reverse the metabolic abnormalities associated with lipoatrophy. Diabetes 51:2727–2733[Abstract/Free Full Text]
  39. Lee CH, Olson P, Evans RM 2003 Minireview: lipid metabolism, metabolic diseases, and peroxisome proliferator-activated receptors. Endocrinology 144:2201–2207[Abstract/Free Full Text]
  40. He W, Barak Y, Hevener A, Olson P, Liao D, Le J, Nelson M, Ong E, Olefsky JM, Evans RM 2003 Adipose-specific peroxisome proliferator-activated receptor {gamma} knockout causes insulin resistance in fat and liver but not in muscle. Proc Natl Acad Sci USA 100:15712–15717[Abstract/Free Full Text]
  41. Caron M, Auclair M, Vigouroux C, Glorian M, Forest C, Capeau J 2001 The HIV protease inhibitor indinavir impairs sterol regulatory element-binding protein-1 intranuclear localization, inhibits preadipocyte differentiation, and induces insulin resistance. Diabetes 50:1378–1388[Abstract/Free Full Text]
  42. Bastard JP, Caron M, Vidal H, Jan V, Auclair M, Vigouroux C, Luboinski J, Laville M, Maachi M, Girard PM, Rozenbaum W, Levan P, Capeau J 2002 Association between altered expression of adipogenic factor SREBP1 in lipoatrophic adipose tissue from HIV-1-infected patients and abnormal adipocyte differentiation and insulin resistance. Lancet 359:1026–1031[CrossRef][Medline]
  43. Adams M, Montague CT, Prins JB, Holder JC, Smith SA, Sanders L, Digby JE, Sewter CP, Lazar MA, Chatterjee VK, O’Rahilly S 1997 Activators of peroxisome proliferator-activated receptor {gamma} have depot-specific effects on human preadipocyte differentiation. J Clin Invest 100:3149–3153[Medline]
  44. Hadigan C, Yawetz S, Thomas A, Havers F, Sax PE, Grinspoon S 2004 Metabolic effects of rosiglitazone in HIV lipodystrophy: a randomized, controlled trial. Ann Intern Med 140:786–794[Abstract/Free Full Text]
  45. Gavrila A, Hsu W, Tsiodras S, Doweiko J, Gautam S, Martin L, Moses AC, Karchmer AW, Mantzoros CS 2005 Improvement in highly active antiretroviral therapy-induced metabolic syndrome by treatment with pioglitazone but not with fenofibrate: a 2 x 2 factorial, randomized, double-blinded, placebo-controlled trial. Clin Infect Dis 40:745–749[Medline]



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