Katherine Samaras

A syndrome of peripheral lipodystrophy, hyperlipidaemia and insulin resistance in patients receiving Hiv protease inhibitors

Objective:To describe a syndrome of peripheral lipodystrophy (fat wasting of the face, limbs and upper trunk), hyperlipidaemia and insulin resistance in patients receiving potent HIV protease inhibitor therapy. Design:Cross-sectional study. Setting:Outpatient clinic of a university teaching hospital. Patients:HIV-infected patients either receiving at least one protease inhibitor (n = 116) or protease inhibitor-naive (n = 32), and healthy men (n = 47). Interventions and main outcome measures:Lipodystrophy was assessed by physical examination and questionnaire and body composition by dual-energy X-ray absorptiometry. Fasting triglyceride, cholesterol, free fatty acid, glucose, insulin, C-peptide and fructosamine levels, other metabolic parameters, CD4 lymphocyte counts, and HIV RNA load were also assessed. Results:HIV protease inhibitor-naive patients had similar body composition to healthy men. HIV protease inhibitor therapy was associated with substantially lower total body fat (13.2 versus 18.7 kg in protease inhibitor-naive patients; P = 0.005), and significantly higher total cholesterol and triglyceride levels. Lipodystrophy was observed clinically in 74 (64%) protease inhibitor recipients after a mean 13.9 months and 1(3%) protease inhibitor-naive patient (P = 0.0001). Fat loss occurred in all regions except the abdomen after a median 10 months. Patients with lipodystrophy experienced a relative weight loss of 0.5 kg per month and had significantly higher triglyceride, cholesterol, insulin and C-peptide levels and were more insulin-resistant than protease inhibitor recipients without lipodystrophy. Patients receiving ritonavir and saquinavir in combination had significantly lower body fat, higher lipids and shorter time to lipodystrophy than patients receiving indinavir. Three (2%) patients developed new or worsening diabetes mellitus. Conclusion:A syndrome of peripheral lipodystrophy, hyperlipidaemia and insulin resistance is a common complication of HIV protease inhibitors. Diabetes mellitus is relatively uncommon.

Pathogenesis of HIV-1-protease inhibitor-associated peripheral lipodystrophy, hyperlipidaemia, and insulin resistance

HIV-1 protease-inhibitor treatments are associated with a syndrome of peripheral lipodystrophy, central adiposity, breast hypertrophy in women, hyperlipidaemia, and insulin resistance. The catalytic region of HIV-1 protease, to which protease inhibitors bind, has approximately 60% homology to regions within two proteins that regulate lipid metabolism: cytoplasmic retinoic-acid binding protein type 1 (CRABP-1) and low density lipoprotein-receptor-related protein (LRP). We hypothesise that protease inhibitors inhibit CRABP-1-modified, and cytochrome P450 3A-mediated synthesis of cis-9-retinoic acid, a key activator of the retinoid X receptor; and peroxisome proliferator activated receptor type gamma (PPAR-gamma) heterodimer, an adipocyte receptor that regulates peripheral adipocyte differentiation and apoptosis. Protease-inhibitor binding to LRP would impair hepatic chylomicron uptake and triglyceride clearance by the endothelial LRP-lipoprotein lipase complex. The resulting hyperlipidaemia contributes to central fat deposition (and in the breasts in the presence of oestrogen), insulin resistance, and, in susceptible individuals, type 2 diabetes. Understanding the syndromes pathogenesis should lead to treatment strategies and to the design of protease inhibitors that do not cause this syndrome.

Prevalence of Metabolic Syndrome in HIV-Infected Patients Receiving Highly Active Antiretroviral Therapy Using International Diabetes Foundation and Adult Treatment Panel III Criteria: Associations with insulin resistance, disturbed body fat compartmentalization, elevated C-reactive protein, and hypoadiponectinemia

OBJECTIVE—Metabolic syndrome is a cluster of risk factors for cardiovascular disease and type 2 diabetes. Definitions exist to identify those “at risk.” Treatment of HIV infection with highly active antiretroviral therapy can induce severe metabolic complications including lipodystrophy, dyslipidemia, and insulin resistance. The purpose of this study was to report the prevalence of metabolic syndrome in HIV-infected patients and compare insulin resistance and total body, limb, and visceral fat and adipokines in those with and without metabolic syndrome. RESEARCH DESIGN AND METHODS—This was an international cross-sectional study of a well-characterized cohort of 788 HIV-infected adults recruited at 32 centers. Metabolic syndrome prevalence was examined using International Diabetes Federation (IDF) and U.S. National Cholesterol Education Program Adult Treatment Panel III (ATPIII) criteria, relative to body composition (whole-body dual-energy X-ray absorptiometry and abdominal computed tomography), lipids, glycemic parameters, insulin resistance, leptin, adiponectin, and C-reactive protein (CRP). RESULTS—The prevalence of metabolic syndrome was 14% (n = 114; 83 men) by IDF criteria and 18% (n = 139; 118 men) by ATPIII criteria; the concordance was significant but only moderate (κ = 0.46, P < 0.0001). Many patients (49%) had at least two features of metabolic syndrome but were not classified as having metabolic syndrome as their waist circumferences or waist-to-hip ratios were in the non–metabolic syndrome range. Metabolic syndrome was more common in those currently receiving protease inhibitors (P = 0.04). Type 2 diabetes prevalence was five- to ninefold higher in those with metabolic syndrome. With IDF criteria, subjects with metabolic syndrome showed disturbances in inflammation and adipokines: they had higher CRP (5.5 ± 7.0 vs. 3.9 ± 6.0 mg/l, P < 0.003) and leptin (9 ± 9 vs. 4 ± 6 ng/ml, P < 0.0001) and lower adiponectin (12 ± 8 vs. 15 ± 10 μg/ml, P < 0.0001) levels. By ATPIII criteria, those with metabolic syndrome had higher leptin (6 ± 8 ng/ml, P = 0.006) and lower adiponectin (15 ± 10 vs. 18 ± 8 μg/ml, P < 0.0001) levels. CONCLUSIONS—Metabolic syndrome prevalence in HIV-positive adults was lower than that reported for the general population. Metabolic syndrome was associated with a substantially increased prevalence of type 2 diabetes in this specific cohort. Many subjects without metabolic syndrome had at least two metabolic syndrome components (particularly elevated lipid levels) but did not meet waist circumference or waist-to-hip ratio cutoff metabolic syndrome criteria in this group with high rates of body fat partitioning disturbances.

No effect of rosiglitazone for treatment of HIV-1 lipoatrophy: randomised, double-blind, placebo-controlled trial

BACKGROUND Lipodystrophy commonly complicates antiretroviral therapy of HIV-1 infection. Thiazolidinediones such as rosiglitazone promote subcutaneous fat growth in type 2 diabetics and adults with congenital lipodystrophy, and can prevent HIV-1 protease inhibitor toxicity to adipocytes in vitro. We postulated that rosiglitazone would improve HIV lipoatrophy. METHODS 108 HIV-1-infected lipoatrophic adults on antiretroviral therapy were randomised to rosiglitazone 4 mg twice daily (n=53) or matching placebo (n=55) for 48 weeks. The study had 80% power to detect a 0.5 kg difference in changes in limb fat (using dual-energy X-ray absorptiometry) between groups at week 48 by intention-to-treat analysis, and a 0.7 kg difference within each protease inhibitor stratum. FINDINGS Limb fat increased by 0.14 kg in the rosiglitazone group and 0.18 kg in the placebo group (mean difference -0.04 kg [95%CI -0.29 to 0.21]; p=0.74 by t test), with three participants (one on rosiglitazone and two controls), lost to follow-up. Rosiglitazone had no significant benefit on any other measure of lipodystrophy, despite large relative increases in plasma adiponectin (4.2 mmol/L [102%]; p<0.0001) and in three markers of insulin sensitivity (p=0.01 to 0.02). Six participants ceased study drug in each group, four participants (three on rosiglitazone and one control) for related adverse events. The main adverse effects, which seem to be almost unique to this population, were asymptomatic hypertriglyceridaemia (mean relative increase 0.9 mmol/L at week 48; p=0.04) and hypercholesterolaemia (1.5 mmol/L; p=0.001). INTERPRETATION Rosiglitazone for 48 weeks did not improve lipoatrophy in HIV-1-infected adults receiving antiretroviral therapy. Use of less toxic antiretroviral treatment is necessary to prevent lipoatrophy.

Epigenetics and human obesity

Background:Recent technological advances in epigenome profiling have led to an increasing number of studies investigating the role of the epigenome in obesity. There is also evidence that environmental exposures during early life can induce persistent alterations in the epigenome, which may lead to an increased risk of obesity later in life.Method:This paper provides a systematic review of studies investigating the association between obesity and either global, site-specific or genome-wide methylation of DNA. Studies on the impact of pre- and postnatal interventions on methylation and obesity are also reviewed. We discuss outstanding questions, and introduce EpiSCOPE, a multidisciplinary research program aimed at increasing the understanding of epigenetic changes in emergence of obesity.Results:An electronic search for relevant articles, published between September 2008 and September 2013 was performed. From the 319 articles identified, 46 studies were included and reviewed. The studies provided no consistent evidence for a relationship between global methylation and obesity. The studies did identify multiple obesity-associated differentially methylated sites, mainly in blood cells. Extensive, but small, alterations in methylation at specific sites were observed in weight loss intervention studies, and several associations between methylation marks at birth and later life obesity were found.Conclusions:Overall, significant progress has been made in the field of epigenetics and obesity and the first potential epigenetic markers for obesity that could be detected at birth have been identified. Eventually this may help in predicting an individual’s obesity risk at a young age and opens possibilities for introducing targeted prevention strategies. It has also become clear that several epigenetic marks are modifiable, by changing the exposure in utero, but also by lifestyle changes in adult life, which implies that there is the potential for interventions to be introduced in postnatal life to modify unfavourable epigenomic profiles.

Subcutaneous and visceral adipose tissue gene expression of serum adipokines that predict type 2 diabetes.

Type 2 diabetes mellitus (T2D) is predicted by central obesity and circulating adipokines regulating inflammation. We hypothesized that visceral adipose tissue (VAT) in T2D expresses greater levels of proinflammatory molecules. Paired samples of subcutaneous (SAT) and VAT were excised at elective surgery (n = 16, 6 with T2D, n = 8 age‐ and gender‐ matched controls). Metabolic parameters were measured in the fasted state: body composition by dual‐energy X‐ray absorptiometry and insulin action by hyperinsulinemic–euglycemic clamp. Adipose tissue mRNA gene expression was measured by quantitative reverse transcriptase‐PCR. Subjects with T2D had higher VAT expression of molecules regulating inflammation (tumor necrosis factor‐α (TNFα), macrophage inflammatory protein (MIP), interleukin‐8 (IL‐8)). Fasting glucose related to VAT expression of TNFα, MIP, serum amyloid A (SAA), IL‐1α, IL‐1β, IL‐8, and IL‐8 receptor. Abdominal fat mass was related to VAT expression of MIP, SAA, cAMP response element–binding protein (CREBP), IL‐1β, and IL‐8. Insulin action related inversely to VAT complement C3 expression only. There were depot‐specific differences in expression of serum T2D predictors: VAT expressed higher levels of complement C3; SAT expressed higher levels of retinol‐binding protein‐4 (RBP4), adiponectin, and leptin. In summary, VAT in T2D expresses higher levels of adipokines involved in inflammation. VAT expression of these molecules is related to fasting glucose and insulin action. Increased production of these proinflammatory molecules by VAT may explain the links observed between visceral obesity, insulin resistance, and diabetes risk.

Obesity Is an Important Determinant of Baseline Serum C-Reactive Protein Concentration in Monozygotic Twins, Independent of Genetic Influences

Background—C-reactive protein (CRP) values predict atherothrombotic cardiovascular disease and type 2 diabetes mellitus. Associations between CRP and obesity, predominantly assessed anthropometrically, may partly explain these observations. Previous studies have been unable to control for genetic influences on CRP and obesity. The aim of this study was to examine the relationship between CRP and accurately measured body fat, lipids, apolipoproteins, blood pressure, and environmental and behavioral factors, independent of genetic influences. Methods and Results—One hundred ninety-four healthy female twins (age 57.2±7 years) were studied after excluding pairs with CRP values >10 mg/L. Total body fat and central abdominal fat (CAF) were measured by dual-energy x-ray absorptiometry. CRP concentration was strongly related to surrogate and direct measures of body fat (r =0.31 to 0.54, P <0.001), diastolic blood pressure (r =0.20, P =0.003), and lipid and apolipoprotein levels (r =0.21 to 0.51, P <0.008). Light-to-moderate alcohol consumers and nonusers of hormone replacement therapy (HRT) had lower CRP levels than abstainers and HRT users, respectively. In stepwise multiple regression analysis, CAF, triglycerides, apolipoprotein B, and HRT use explained 46% of the variance in circulating CRP. In analyses controlling for genetic influences in monozygotic twins, within-pair differences in CRP were associated with within-pair differences in total body fat (r =0.39, P <0.001), CAF (r =0.34, P =0.002), diastolic blood pressure (r =0.24, P =0.03), apolipoprotein AI (r =−0.33, P =0.01), HDL cholesterol (r =−0.42, P =0.001), and triglycerides (r =0.35, P =0.007). Conclusions—CRP was strongly related to total and central abdominal obesity, blood pressure, and lipid levels, independent of genetic influences. These relationships are likely to contribute significantly to prospective associations between CRP and type 2 diabetes and coronary events.

In Vivo, Nucleoside Reverse-Transcriptase Inhibitors Alter Expression of Both Mitochondrial and Lipid Metabolism Genes in the Absence of Depletion of Mitochondrial DNA

BACKGROUND Nucleoside reverse-transcriptase inhibitors (NRTIs), which are used to treat human immunodeficiency virus (HIV) infection, can cause mitochondrial dysfunction and have been associated with lipoatrophy. The effects of this mitochondrial dysfunction on lipid metabolism, at a molecular level in vivo, have not been described. METHODS We examined early changes (by 2 weeks after initiation of therapy) in expression of mitochondrial and nuclear genes in adipose tissue from 20 HIV-negative subjects randomized to receive dual-NRTI therapy (zidovudine/lamivudine or stavudine/lamivudine) for 6 weeks. RESULTS We observed decreased transcription of mitochondrial (mt) RNA without significant depletion of mtDNA. Decreases in mtRNA coincided with simultaneous up-regulation of nuclear genes involved in transcriptional regulation of mtRNA (NRF1 and TFAM) and oxidation of fatty acids (PPARA and LPL), whereas PPARG, which is important for differentiation of adipose tissue, was down-regulated. Many nuclear changes correlated with changes in peroxisome proliferator-activated receptor-gamma coactivator-1 (PGC1), suggesting a central role for PGC1 in nuclear responses to mitochondrial dysfunction. Expression of peripheral blood monocyte mtRNA also decreased, suggesting that monocytes may be surrogates for NRTI-induced mitochondrial dysfunction in other tissues. CONCLUSIONS Independent of HIV, NRTIs decrease transcription of mtRNA in vivo. The absence of depletion of mtDNA suggests that NRTIs cause mitochondrial dysfunction by means other than through inhibition of DNA polymerase- gamma , whereas disruption of expression of lipid metabolism genes offers an explanation for NRTI-induced lipoatrophy.

Metabolic syndrome, cardiovascular disease and type 2 diabetes mellitus after initiation of antiretroviral therapy in HIV infection

Background:Metabolic syndrome (MS) identifies individuals at risk of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). Little is known about MS and its consequences following initiation of antiretroviral therapy (ART). Methods:HIV-infected adults (881) initiating ART were evaluated for prevalence and incidence of MS and subsequent diagnosis of CVD and T2DM over a 3-year period. MS was defined by criteria of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Third Report; ATP-III) or of the International Diabetes Federation (IDF). Results:The prevalence of baseline MS was 8.5% and 7.8% (ATP-III and IDF, respectively). During follow-up, 234 (12/100 patient-years) (ATP-III) and 178 (8/100 patient-years) (IDF) progressed to MS. MS at baseline had a borderline association with increased risk of CVD [ATP-III: hazard ratio (HR), 2.56; 95% confidence interval (CI), 0.86–7.60; P = 0.095; IDF: HR, 2.89; 95% CI, 0.98–8.63; P = 0.058] and was significantly associated with an increased risk of T2DM (ATP-III: HR, 4.34; 95% CI, 1.83–10.25; P = 0.001; IDF: HR, 3.33; 95% CI, 1.35–8.17; P = 0.009). Incident MS was significantly associated with an increased risk of both CVD (ATP-III: HR, 2.73; 95% CI, 1.07–6.96; P = 0.036; IDF: HR, 3.05; 95% CI, 1.20–7.75; P = 0.019) and T2DM (ATP-III: HR, 4.89; 95% CI, 2.22–10.78; P < 0.0001; IDF: HR, 4.84; 95% CI, 2.20–10.64; P < 0.0001). Conclusions:Substantial progression to MS occurs within 3 years following initiation of ART. Since baseline and incident MS identifies individuals at risk for subsequent CVD and T2DM, it warrants evaluation in patients commencing ART.

Low Bone Mineral Density, Renal Dysfunction, and Fracture Risk in HIV Infection: A Cross-Sectional Study

BACKGROUND Reduced bone mineral density (BMD) is common in adults infected with human immunodeficiency virus (HIV). The role of proximal renal tubular dysfunction (PRTD) and alterations in bone metabolism in HIV-related low BMD are incompletely understood. METHODS We quantified BMD (dual-energy x-ray absorptiometry), blood and urinary markers of bone metabolism and renal function, and risk factors for low BMD (hip or spine T score, -1 or less) in an ambulatory care setting. We determined factors associated with low BMD and calculated 10-year fracture risks using the World Health Organization FRAX equation. RESULTS We studied 153 adults (98% men; median age, 48 years; median body mass index, 24.5; 67 [44%] were receiving tenofovir, 81 [53%] were receiving a boosted protease inhibitor [PI]). Sixty-five participants (42%) had low BMD, and 11 (7%) had PRTD. PI therapy was associated with low BMD in multivariable analysis (odds ratio, 2.69; 95% confidence interval, 1.09-6.63). Tenofovir use was associated with increased osteoblast and osteoclast activity (P< or = .002). The mean estimated 10-year risks were 1.2% for hip fracture and 5.4% for any major osteoporotic fracture. CONCLUSIONS In this mostly male population, low BMD was significantly associated with PI therapy. Tenofovir recipients showed evidence of increased bone turnover. Measurement of BMD and estimation of fracture risk may be warranted in treated HIV-infected adults.