Identification of novel genetic variations in ABCB6 and GRN genes associated with HIV-associated lipodystrophy

Protease inhibitors (PIs) are associated with an incidence of lipodystrophy among people living with HIV(PLHIV). Lipodystrophiesare characterised by the loss of adipose tissue. Evidence suggests that a patient's lipodystrophy phenotype is influenced by genetic mutation, age, gender, and environmental and genetic factors, such as single-nucleotide variants (SNVs). Pathogenic variants are considered to cause a more significant loss of adipose tissue compared to non-pathogenic. Lipid metabolising enzymes and transporter genes have a role in regulating lipoprotein metabolism and have been associated with lipodystrophy in HIV-infected patients (LDHIV). The long-term effect of the lipodystrophy syndrome is related to cardiovascular diseases (CVDs). Hence, we determined the SNVs of lipid metabolising enzymes and transporter genes in a total of 48 patient samples, of which 24 were with and 24 were without HIV-associated lipodystrophy (HIVLD) using next-generation sequencing. A panel of lipid metabolism, transport and elimination genes were sequenced. Three novel heterozygous non-synonymous variants at exon 8 (c.C1400A:p.S467Y, c.G1385A:p.G462E, and c.T1339C:p.S447P) in the ABCB6 gene were identified in patients with lipodystrophy. One homozygous non-synonymous SNV (exon5:c.T358C:p.S120P) in the GRN gene was identified in patients with lipodystrophy. One novelstop-gain SNV (exon5:c.C373T:p.Q125X) was found in the GRN gene among patients without lipodystrophy. Patients without lipodystrophy had one homozygous non-synonymous SNV (exon9:c.G1462T:p.G488C) in the ABCB6 gene. Our findings suggest that novel heterozygous non-synonymous variants in the ABCB6 gene may contribute to defective protein production, potentially intensifying the severity of lipodystrophy. Additionally, identifying a stop-gain SNV in the GRN gene among patients without lipodystrophy implies a potential role in the development of HIVLD.

Relationship Between Adiposity Indices, Lipodystrophy, and Sarcopenia in HIV-Positive Individuals With and Without Lipodystrophy

Metabolism disorders, as well as body shape abnormalities, have been associated with the introduction of antiretroviral therapy. The objective of this study was to compare the diagnostic ability of adiposity indices and to discuss criteria for the classification of lipodystrophy and sarcopenia (SP) in HIV-positive individuals. Anthropometric measurements were determined in 268 individuals of both genders, also submitted to the dual-energy X-ray absorptiometry exam. The adiposity indices calculated were body mass index, body mass index adjusted for fat mass (BMIfat), body adiposity index, body adiposity Index for the Fels Longitudinal Study sample, and The Clínica Universidad de Navarra body adiposity estimator. The presence of lipodystrophy was evaluated using the fat mass ratio (FMR). SP was classified using the appendicular lean mass/height² ratio. The subjects were divided into 3 groups: HIV⁺LIPO⁺ (n = 41), HIV⁺LIPO^- (n = 65), and control (C, HIV-negative individuals; n = 162). Among the adiposity indices assessed, BMIfat showed the strongest correlation with total body fat (in percent) for men (r = 0.87, p < 0.001) and women (r = 0.92, p < 0.001). The frequency of SP was 44.8% and 41.7% in HIV⁺LIPO⁺, 27.8% and 20.7% in HIV⁺LIPO^- and 63.3% and 45.45% in C, for men and women, respectively. The cutoff point suggested for the diagnosis of lipodystrophy according to the FMR was 1.14. The adiposity indices, particularly the BMIfat, have strong correlation with body fat determined by dual-energy X-ray absorptiometry in HIV-positive patients. The implementation of FMR is recommended for more standardized estimates of the frequency of lipodystrophy.

Altered relationship of plasma triglycerides to HDL cholesterol in patients with HIV/HAART-associated dyslipidemia: further evidence for a unique form of metabolic syndrome in HIV patients

INTRODUCTION

Plasma triglycerides (TG) and HDL-C are inversely related in Metabolic Syndrome (MetS), due to exchange of VLDL-TG for HDL-cholesteryl esters catalyzed by cholesteryl ester transfer protein (CETP). We investigated the relationship of TG to HDL-C in highly-active antiretroviral drug (HAART)-treated HIV patients.

METHODS

Fasting plasma TG and HDL-C levels were compared in 179 hypertriglyceridemic HIV/HAART patients and 71 HIV-negative persons (31 normotriglyceridemic (NL) and 40 hypertriglyceridemic due to type IV hyperlipidemia (HTG)). CETP mass and activity were compared in 19 NL and 87 HIV/HAART subjects.

RESULTS

Among the three groups, a plot of HDL-C vs. TG gave similar slopes but significantly different y-intercepts (9.24±0.45, 8.16±0.54, 6.70±0.65, sqrt(HDL-C) for NL, HIV and HTG respectively; P<0.001); this difference persisted after adjusting HDL-C for TG, age, BMI, gender, glucose, CD4 count, viral load and HAART strata (7.18±0.20, 6.20±0.05 and 4.55±0.15 sqrt(HDL-C) for NL, HIV and HTG, respectively, P<0.001). CETP activity was not different between NL and HIV, but CETP mass was significantly higher in HIV (1.47±0.53 compared to 0.93±0.27μg/mL, P<0.0001), hence CETP specific activity was lower in HIV (22.67±13.46 compared to 28.46±8.24nmol/μg/h, P=0.001).

CONCLUSIONS

Dyslipidemic HIV/HAART patients have a distinctive HDL-C plasma concentration adjusted for TG. The weak inverse relationship between HDL-C and TG is not explained by altered total CETP activity; it could result from a non-CETP-dependent mechanism or a decrease in CETP function due to inhibitors of CETP activity in HIV patients' plasma.

Prevalence of obesity and its relationship to clinical lipodystrophy in HIV-infected adults on anti-retroviral therapy

BACKGROUND

Combination antiretroviral therapy (cART) is associated with lipodystrophy (lipoatrophy and lipoaccumulation) and several metabolic abnormalities that together can contribute to an increased cardiovascular risk. The aim of this study was to evaluate the prevalence of obesity in patients on cART according to the presence of clinical lipodystrophy (CL) and to analyze factors associated with obesity.

METHODS

We evaluated 368 HIV-infected adults on cART.

RESULTS

CL was present in 59.0%. Independently of gender, patients with CL were more frequently underweight [5.7% (21/368)] and of normal weight [47.3% (174/368)], and less frequently overweight [33.2% (122/368)] or obese [13.9% (51/368)]. Mean body mass index was higher in patients with abdominal prominence regardless of the presence of clinical lipoatrophy. Patients with CL had lower waist circumference, higher waist/hip and fat mass ratio and lower total and subcutaneous fat, without significant difference in visceral fat but with a higher visceral/subcutaneous fat ratio, as evaluated by CT at abdominal level. CL was significantly less frequent in overweight [odds ratio (OR)=0.21, 95% confidence interval (CI): 0.05-0.92] and obese (OR=0.05, 95%CI: 0.01-0.26) patients, when compared to underweight ones, independent of age, gender, duration of infection, cART regimen, virological suppression, and HIV-infection risk factor.

CONCLUSIONS

Being overweight or obese is highly prevalent in HIV-infected patients on cART. Patients with CL were more frequently under- or normal weight, and less frequently overweight or obese. Obesity is a condition that should be considered in HIV patients on cART.

Deiodinase 2 expression is increased in dorsocervical fat of patients with HIV-associated lipohypertrophy syndrome

CONTEXT

The pathogenesis and function of dorsocervical sc adipose tissue (DSAT) accumulation in HIV-infected patients is not known. Previous investigations using either UCP-1 expression or positron emission tomography have been inconclusive as to whether this depot represents brown adipose tissue (BAT). We investigated DSAT gene expression, including DIO2, a deiodinase that contributes to increased thermogenesis in brown fat, and simultaneously determined [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) uptake in lipodystrophic HIV and healthy control subjects.

DESIGN

Thirteen HIV-infected and three non-HIV-infected men were recruited. HIV-infected subjects had evidence of significant lipodystrophy, including fat atrophy of the face, arms, and legs, and/or fat accumulation of the neck and abdomen. Subjects were cooled, followed by [¹⁸F]FDG positron emission tomography/computed tomography, fat biopsy of DSAT, and measurement of resting energy expenditure (REE). HIV-infected subjects were characterized as lipohypertrophic and lipoatrophic and compared.

RESULTS

Mean standardized uptake value of [¹⁸F]FDG and UCP-1 expression were not significantly different in DSAT among the groups. However, lipohypertrophic subjects demonstrated increased expression of DIO2 in DSAT compared with lipoatrophic subjects (P = 0.03). Among HIV-infected patients, DIO2 expression was strongly related to REE (r = 0.78, P = 0.002) and was a predictor of REE in multivariate modeling controlling for age, TSH, and lean body mass (r² = 0.79, P = 0.008). One control subject demonstrated typical BAT in the supraclavicular area.

CONCLUSIONS

Adipose tissue accumulating in the dorsocervical area in HIV lipodystrophy does not appear to be classical BAT. However, DIO2 expression is increased in DSAT among patients with HIV lipodystrophy, particularly those with increased visceral adiposity, and is positively associated with energy expenditure.

Serum retinol-binding protein 4 correlates with obesity, insulin resistance, and dyslipidemia in HIV-infected subjects receiving highly active antiretroviral therapy

Highly active antiretroviral therapy (HAART) contributes to the development of metabolic complications including dyslipidemia, insulin resistance (IR), and lipodystrophy (LD). Recent studies reported that retinol-binding protein 4 (RBP4) is associated with IR, dyslipidemia, and obesity in non-HIV-infected populations. The aim of this study was to evaluate the associations between RBP4 and LD or metabolic abnormalities in HIV-infected subjects receiving HAART. We performed a cross-sectional study with 113 HIV-infected subjects receiving HAART for more than 6 months. Body composition and abdominal fat were measured by bioelectrical impedance analysis and ultrasonography, and fasting serum RBP4 was measured by enzyme-linked immunosorbent assay. Retinol-binding protein 4 levels in subjects with LD were similar to those without LD (P = .839). Retinol-binding protein 4 had significantly positive correlations with waist circumference (r = 0.298, P = .002), waist-to-hip ratio (r = 0.336, P = .001), body mass index (r = 0.310, P = .002), total body fat mass (r = 0.323, P = .001), total cholesterol (r = 0.188, P = .048), log (triglyceride) (r = 0.269, P = .004), and log (homeostasis model assessment of IR) (r = 0.207, P = .036), and negative correlations with quantitative insulin sensitivity check index (r = -0.209, P = .034) after adjustment for age and sex. In stepwise multivariate linear regression analysis, waist-to-hip ratio was the most significant independent predictor of increased RBP4 (standardized beta = .351, P = .001). These results suggest that serum RBP4 is associated with obesity, IR, and dyslipidemia in HIV-infected subjects receiving HAART.

Hypoadiponectinemia in lipodystrophic HIV individuals: a metabolic marker of subclinical cardiac damage

BACKGROUND AND AIM

To evaluate cardiovascular abnormalities in highly active antiretroviral therapy (HAART) treated HIV patients with no signs or symptoms of cardiovascular impairment, and to assess the relative role of multiple concomitant risk factors.

METHODS AND RESULTS

Forty-four consecutive HIV subjects (mean age 41+/-6 yrs) were enrolled. Inclusion criteria were HIV infection, CD4+cell count>150/ml, HAART treatment for at least 4 years. Metabolic serum levels, morphological and functional echocardiographic parameters were assessed in all subjects. Sixteen healthy age and sex matched subjects with no cardiovascular risk factors were recruited as controls. HIV patients showed increased left ventricular mass index with reduced mid-wall fractional shortening (mFS) when compared to controls (50.2+/-10.5 vs. 38.6+/-14.4, p=0.05 and 18.3+/-0.6 vs. 21.9+/-0.7, p<0.05, respectively). Twenty-nine patients were lipodystrophic (LD) and showed a longer HAART period (p=0.0004) and greater use of protease inhibitors (PI) (p=0.001). Coronary flow reserve (CFR) was significantly reduced in HIV patients as compared to controls (p<0.0001), as it was in LD subjects when compared to non-lipodystrophic ones (NLD) (p<0.001). Adiponectin concentrations were found to be significantly lower in LD subjects than in NLD ones (7.8+/-0.8 vs. 13.8+/-1.2 microg/ml, p=0.01), and showed a direct correlation with CFR. In multiple regression analysis, insulin, HDL and adiponectin accounted for 63% of CFR variations.

CONCLUSIONS

Left ventricular hypertrophy, depressed mFS and reduced CFR represent the main signs of subclinical cardiac damage in HIV subjects treated with HAART. Hypoadiponectinemia in these subjects seems to be a metabolic risk factor of cardiovascular impairment.

Hypopituitarism and HIV-infection: a new comorbidity in the HAART era?

Several comorbidities are associated with the HIV infection and may involve also the endocrine-metabolic system. Consistently, the recent development of the therapeutic regimen highly active antiretroviral therapy (HAART) ruled out a significant improvement both in the prognosis and life expectancy of HIV-infected patients, but disclosed also new serious drug-related toxicity. Of these, the lipodystrophy syndrome is the most frequent, occurring in up to 83% of HIV-infected patients under HAART. The HIV-related lipodystrophy is associated with alterations in GH dynamics, affecting both basal and stimulated GH secretion. This GHIGF- I secretive pattern resembles that of severe GH deficiency in adulthood due to pituitary diseases, but without leading to IGF-I serum levels below the normal range. The impairment of pituitary GH secretion has been ascribed to the hormonal and metabolic inhibitory effect due to adipose tissue redistribution in HIV-infected males, since in these patients pituitary GH secretion appeared to be inversely related to visceral adipose tissue accumulation and waist to-hip-ratio. However, whether these patients suffer from a true GH deficiency due to an intrinsic pituitary failure or display only a functional reduction of GH secretion due to visceral adiposity remains still a matter of debate, especially in HIV-infected females.

Treatment of facial lipoatrophy in HIV-infected patients

Standard management for facial lipoatrophy caused by antiretroviral drugs includes switching drugs and surgical autografting of adipose tissue. Local injections of polylactic acid have not been compared with surgery. Benefits usually seem to outweigh adverse effects in the short term but few long-term results are available.

Antiretroviral therapy and the human immunodeficiency virus--improved survival but at what cost?

Patients infected with human immunodeficiency virus are living longer since the introduction of combination antiretroviral therapy more than a decade ago - but at what cost? Highly active antiretroviral therapy has been associated with lipodystrophy and associated metabolic derangements such as dyslipidaemia, insulin resistance and diabetes. These complications are likely to contribute to an increased risk of premature and accelerated atherosclerosis with growing concern about potential cardiovascular consequences.

HIV lipodystrophy and its metabolic consequences: implications for clinical practice

BACKGROUND

The introduction of highly active antiretroviral therapy (HAART) around 1996 markedly reduced mortality and morbidity from human immunodeficiency virus (HIV) infection. As life expectancy has improved, the chronic complications of HIV and HAART have become increasingly relevant.

SCOPE

This article provides an overview of the HIV-associated lipodystrophy, its pathogenesis and its clinical consequences (based on a search strategy in PubMed including literature published to November 2007).

FINDINGS

Lipodystrophy syndrome is characterized by abnormal fat distribution syndrome associated with metabolic disturbances and includes insulin resistance, deranged glucose and lipid metabolism. It is associated with increased risks of progression to type 2 diabetes and cardiovascular disease. Robust diagnostic criteria are required for lipodystrophy, and subsequent prospective cohort studies and randomized controlled trials are then required to determine the etiology and prognosis of lipodystrophy, and to evaluate therapeutic interventions for this consequence of HAART. Therapies to improve insulin resistance have been tried but they are frequently ineffective, and are limited by potential toxicity in this population. Hence, current management options for HIV associated lipodystrophy are limited and are mostly based on avoidance of risk factors and switching of antiretroviral drugs.

CONCLUSION

As the '3 by 5 strategy' of providing HIV drugs to the developing world is implemented worldwide, the numbers of patients adhering to antiretroviral medicines is dramatically increasing. One must be aware that in reducing the burden of acute retroviral disease, the treatments proposed might lead to significant rates of metabolic complications and further exacerbation of the epidemic of diabetes and cardiovascular disease.

A Randomized, Placebo‐Controlled Trial of Rosiglitazone for HIV‐Related Lipoatrophy

BACKGROUND

Thiazolidinediones such as rosiglitazone may have benefit in ameliorating human immunodeficiency virus (HIV) lipoatrophy.

METHODS

HIV-positive patients receiving stable, protease inhibitor-containing highly active antiretroviral therapy with HIV lipodystrophy were prospectively randomized to rosiglitazone (4 mg/day) or placebo. The primary end point was the 24-week percentage change in arm fat by dual-energy x-ray absorptiometry (DEXA). Clinical and anthropometric evaluations, fasting lipid parameters, oral glucose tolerance testing, CD36 expression, quality of life measures, and DEXA scanning were performed at baseline and week 24.

RESULTS

Seventy-eight of the 96 enrolled patients were evaluated. Median age was 46.8 years, 97.4% were male, and 54% were treated with thymidine analogues. Median baseline limb fat was 3.76 and 2.99 kg in the rosiglitazone and control groups, respectively. Median changes in arm, leg, trunk, and total body fat at 24 weeks were not significantly different between groups (7.1% vs. 5.0% [P=.94]; 0.1% vs. -2.4% [P=.90]; 1.2% vs. -1.4% [P=.81]; and 1.7% vs. 0.4% [P=.76]). There were no significant changes in secondary end points. There was no correlation between changes in body fat or treatment-arm and CD36 expression.

CONCLUSIONS

This randomized, placebo-controlled trial did not show benefit of 4 mg/day of rosiglitazone on lipoatrophy or metabolic parameters in patients with HIV lipodystrophy.

Long-term complications of antiretroviral therapy: lipoatrophy

The effective use of potent antiretroviral therapy has dramatically improved the life expectancy for HIV-infected individuals. Long-term complications of both HIV-infection and antiretroviral agents are therefore of increasing concern. Lipoatrophy (LA) or fat wasting is a complication most frequently associated with nucleoside reverse transcriptase inhibitors, thymidine analogues particularly. LA can be stigmatising and is associated with psychosocial complication. It can occur in isolation or as part of the 'metabolic' or 'lipodystrophy' syndrome, a triad of LA, fat accumulation and metabolic disturbance (insulin resistance and dyslipidaemia) with a subsequently increased risk of cardiovascular events. We aimed to review the definition, prevalence, pathogenesis, implications and treatment of HIV/highly active antiretroviral therapy-associated fat loss. We performed a review of PubMed, Medline and recent conference abstracts for information on LA. The current treatments available for treating LA are limited. Switching away from thymidine analogues can provide a small benefit but improvement is, at best, slow and partial. Specific medical therapies such as glitazones, metformin and stating have been disappointing to date. Surgical fillers can yield marked results but are costly, time consuming and only of value for facial LA, not other sites. Ultimately, prevention of this condition is the best approach by avoiding thymidine analogues wherever possible or careful monitoring with early switching away from these agents. New therapies to treat pre-existing fat loss are required.

Immediate versus delayed polyalkylimide gel injections to correct facial lipoatrophy in HIV-positive patients

OBJECTIVE

To evaluate the safety and efficacy of polyalkylimide gel (PAIG) in the treatment of HIV-associated facial lipoatrophy.

DESIGN

A randomized, open-label, single-centre study.

METHODS

HIV-positive individuals with facial lipoatrophy (based on physician assessment) were randomly assigned to immediate (weeks 0 and 6) or delayed (weeks 12 and 18) PAIG injections administered into the subcutaneous plane. Outcome measures included a change in facial lipoatrophy severity scores (five-point scale), adverse events, photographic assessment, and changes in quality of life (QoL), depression and anxiety using validated surveys.

RESULTS

Thirty-one patients (median age 48 years, 97% male) were enrolled and completed 48 weeks of follow-up. Overall, the median volume of product injected bilaterally was 16.0 ml. Adverse events, including swelling, redness, bruising and pain, were mild, and resolved after a median of 3 days. There were no cases of necrosis, nodules or infection. Compared with patients randomly assigned to delayed treatment, patients in the immediate therapy group had significantly lower physician-rated facial lipoatrophy scores (0 versus 2; P < 0.0001), improved QoL (P = 0.01), and lower anxiety (P = 0.02) at week 12. At week 48, median physician and patient facial lipoatrophy scores were 0 and 1, respectively, for the entire cohort, and were not significantly different between the groups. Significant improvements in patient anxiety (P = 0.001) and depression (P = 0.01) were observed from baseline to week 48.

CONCLUSION

Treatment with PAIG was effective and safe and led to improvements in facial lipoatrophy grading, QoL, anxiety and depression scores in HIV-infected patients with facial lipoatrophy.

Toxicogenetics of antiretroviral therapy: genetic factors that contribute to metabolic complications

Metabolic complications of antiretroviral therapy (ART) have emerged as a major concern for long-term, successful management of HIV infection. Variability in the response to ART between individuals has been increasingly linked to the genetic background of patients, as regards efficacy and susceptibility to adverse reactions (toxicogenetics). This review summarizes the biological and methodological background for the genetic prediction of metabolic toxicity of ART. Recent studies are discussed which suggest that single-nucleotide polymorphisms (SNPs) in several genes involved in lipid metabolism and lipid transport in the general population (ABCA1, APOA5, APOC3, APOE, CETP) might modulate plasma triglyceride and high-density lipoprotein cholesterol levels in HIV-infected patients. At present, genetic prediction of lipodystrophy is not possible. Lipodystrophy has been linked to an accumulation of mtDNA mutations, a finding causally associated with ageing phenotypes in animal models. No mutations in LMNA, a gene linked to rare, inherited forms of lipodystrophy, have been identified in small studies of patients with lipodystrophy, and a possible link to a TNF promoter SNP remains to be confirmed. With the rapidly decreasing cost of genetic testing, the main issues that need to be addressed prior to introduction of toxicogenetic prediction in HIV clinical practice include reproducibly high predictive values of SNP associations with clinically relevant and well defined metabolic outcomes, studies that evaluate the contribution of SNPs in the context of multi-SNP and haplotype analysis, and the validation of genetic markers in independent, large patient cohorts. Comprehensive, whole genome approaches are increasingly being used.

Hypoadiponectinemia, dyslipidemia, and impaired growth in children with HIV-associated facial lipoatrophy

OBJECTIVE

To compare growth, lipids and adipocytokines in HIV-positive children with and without lipoatrophy.

PATIENTS

Eleven HIV-positive children with facial lipoatrophy, and 22 age- and sex-matched HIV-positive controls without signs of fat abnormality.

METHODS

Clinical data including height, physical examination findings, medications, markers of viral control, cholesterol, and triglycerides were retrieved from the medical charts. Serum samples were analyzed for adiponectin, inflammatory markers, and high density lipoprotein cholesterol (HDL).

RESULTS

Lipoatrophy was associated with higher triglycerides (330 vs 133 mg/dl, p = 0.0003), lower HDL (33 vs 48 mg/dl, p = 0.02), and a greater frequency of hypercholesterolemia (total cholesterol > 200 mg/dl; 64% vs 23%, p < 0.03). Adiponectin was 53% lower in patients with lipodystrophy (6.9 microg/ml vs 14.8 microg/ml, p = 0.005), however there was no difference in the inflammatory markers soluble TNFa receptor 2 or interleukin 6. Strikingly, despite similar BMI z-scores and virological control, lipoatrophic patients were shorter by 1 standard deviation score (p = 0.03).

CONCLUSIONS

The presence of facial lipoatrophy in a child with HIV infection is a marker for significant metabolic derangements including dyslipidemia and hypoadiponectinemia, and suggests the need for careful growth evaluation.

Patogenia de la lipodistrofia y de las alteraciones metabólicas asociadas a la infección por el VIH

Lipodystrophy, and the metabolic alterations (dislipemia, insulin-resistance) associated with human immunodeficiency virus (HIV) infection, is a multifactorial syndrome due to the interaction of host related factors (cellular immune status, diet, gene mutations), viral factors (cytokine synthesis, polyunsaturated fatty acid or PUFA depletion), and pharmacological effects (mitochondrial DNA-polymerase inhibition, lipolysis inhibition, adiponectin synthesis reduction). HIV probably modifies the adipocyte differentiation and the lipid metabolism. This retroviral effect is mediated by proinflammatory cytokines (tumor necrosis factor) and the participation of other factors (drugs, diet), all in the context of a particular host genetic setting. The adipocyte (and several cellular receptors, fatty acids, membrane proteins, and cytokines) plays a central role in the pathogenesis of HIV-associated lipodystrophy.

Disorders of glucose metabolism in the context of human immunodeficiency virus infection

PURPOSE

To discuss the pathophysiology and the current treatment approaches for the dysregulation of glucose metabolism in the context of human immunodeficiency virus (HIV) infection.

DATA SOURCES

Selected research, clinical studies, clinical guidelines, and review articles.

CONCLUSIONS

In HIV infection, multiple factors are associated with the pathogenesis of glucose dysregulation. Studies suggest that protease inhibitors, a class of antiretroviral agent, as well as viral factors, lipodystrophy, hepatitis C infection, injection drug use, and second-generation antipsychotics have been implicated in the development of glucose disorders and diabetes. Current treatment recommendations are based on extrapolated data from non-HIV diabetic patients. More research is needed to establish the most appropriate management for the disorders of glucose metabolism in the context of HIV infection.

IMPLICATIONS FOR PRACTICE

If left untreated, patients are at increased risk for cardiovascular disease and complications associated with untreated diabetes.

The role of diet, exercise and smoking in dyslipidaemia in HIV-infected patients with lipodystrophy

BACKGROUND

Lipodystrophy in HIV-infected (LDHIV) patients receiving protease inhibitors (PIs) is associated with dyslipidaemia. Whether lifestyle factors play a role in dyslipidaemia in LDHIV subjects on PIs is not well characterized.

METHODS

A total of 45 LDHIV male and six LDHIV female patients on PIs were recruited, and data were collected on smoking, exercise, diet (by 3-day food record), and fasting levels of serum lipids and lipoproteins. The relationships between lifestyle factors and metabolic variables were analysed in male patients by Spearman's correlation test and the significant relationships were further analysed by adjusting for age, PI duration, and waist circumference by Spearman's partial correlation test.

RESULTS

In men, mean (+/-standard deviation) serum concentrations of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and non-HDL-C were 212+/-70, 35+/-7.3, 325+/-230 and 169+/-44 mg/dL, respectively. Sixty-seven percent of the men exercised regularly and 31.1% smoked. The reported diet was high in cholesterol (390+/-212 mg) and percentage energy from saturated (12.2+/-3.3%) and trans (2.4+/-1.2%) fats, and low in soluble fibre (6.9+/-2.3 g) compared with recent dietary guidelines. Following adjustments for the confounding variables, percentage energy intake from total protein and animal protein was positively related to TC (r=0.44, P<0.01 and r=0.37, P<0.05, respectively), TG (r=0.40, P<0.01 and r=0.46, P<0.01, respectively) and non-HDL-C (r=0.56, P<0.001 and r=0.49, P<0.01, respectively), that from trans fat was positively related to TG (r=0.34, P<0.05), and soluble fibre was negatively related to non-HDL-C (r=-0.41, P<0.01). Moderate to heavy aerobic exercise tended to be associated with higher HDL-C (r=0.30, P=0.07) whereas smoking was not associated with any of the metabolic variables.

CONCLUSIONS

Increased intake of total protein, animal protein and trans fat, and reduced soluble fibre consumption contribute to dyslipidaemia in LDHIV subjects on PIs.

Incidence of and risk factors for insulin resistance in treatment-naive HIV-infected patients 48 weeks after starting highly active antiretroviral therapy

OBJECTIVES

to assess the incidence and risk factors for insulin resistance (IR) in a cohort of naive HIV-infected patients 48 weeks after starting highly active antiretroviral therapy (HAART).

DESIGN

prospective, two centre, observational, cohort study.

METHODS

One-hundred and thirty-seven patients who started HAART and maintained the same regimen for 48 weeks were included. IR was determined by the homeostasis model assessment (HOMA-IR) method. Individuals with a HOMA-IR value >3.8 were defined as insulin resistant. Independent associations with the development of IR at 48 weeks were evaluated.

RESULTS

Seventeen (12.4%) individuals showed a HOMA-IR value >3.8 at baseline and were excluded for incidence analyses. Fifteen patients developed IR at 48 weeks of HAART, giving an incidence of 13%. Independent predictors of the development or IR were indinavir exposure (beta-coefficient 5.45, 95% confidence interval [CI] 1.30-22.8; P=0.02), and hepatitis C virus (HCV) antibody positivity (beta-coefficient 5.22, 95% CI 1.34-20.33; P=0.01). The appearance of IR was associated with a higher BMI (beta-coefficient 1.72 for each 2 kg/m2 increase, 95% CI 1.54-1.94; P=0.02) and with the presence of lipodystrophy at 48 weeks (beta-coefficient 5.59, 95% CI 1.45-21.5; P=0.01).

CONCLUSIONS

HAART induces the development of IR in previously naive non-insulin-resistant HIV-infected individuals, with an incidence of 13% in the first year of therapy. Indinavir exposure, and HCV coinfection are associated with an increased risk of developing IR.

Increased intramyocellular lipid accumulation in HIV-infected women with fat redistribution

The human immunodeficiency virus (HIV)-lipodystrophy syndrome is associated with fat redistribution and metabolic abnormalities, including insulin resistance. Increased intramyocellular lipid (IMCL) concentrations are thought to contribute to insulin resistance, being linked to metabolic and body composition variables. We examined 46 women: HIV infected with fat redistribution (n = 25), and age- and body mass index-matched HIV-negative controls (n = 21). IMCL was measured by 1H-magnetic resonance spectroscopy, and body composition was assessed with computed tomography, dual-energy X-ray absorptiometry (DEXA), and magnetic resonance imaging. Plasma lipid profile and markers of glucose homeostasis were obtained. IMCL was significantly increased in tibialis anterior [135.0 +/- 11.5 vs. 85.1 +/- 13.2 institutional units (IU); P = 0.007] and soleus [643.7 +/- 61.0 vs. 443.6 +/- 47.2 IU, P = 0.017] of HIV-infected subjects compared with controls. Among HIV-infected subjects, calf subcutaneous fat area (17.8 +/- 2.3 vs. 35.0 +/- 2.5 cm2, P < 0.0001) and extremity fat by DEXA (11.8 +/- 1.1 vs. 15.6 +/- 1.2 kg, P = 0.024) were reduced, whereas visceral abdominal fat (125.2 +/- 11.3 vs. 74.4 +/- 12.3 cm2, P = 0.004), triglycerides (131.1 +/- 11.0 vs. 66.3 +/- 12.3 mg/dl, P = 0.0003), and fasting insulin (10.8 +/- 0.9 vs. 7.0 +/- 0.9 microIU/ml, P = 0.004) were increased compared with control subjects. Triglycerides (r = 0.39, P = 0.05) and extremity fat as percentage of whole body fat by DEXA (r = -0.51, P = 0.01) correlated significantly with IMCL in the HIV but not the control group. Extremity fat (beta = -633.53, P = 0.03) remained significantly associated with IMCL among HIV-infected patients, controlling for visceral abdominal fat, abdominal subcutaneous fat, and antiretroviral medications in a regression model. These data demonstrate increased IMCL in HIV-infected women with a mixed lipodystrophy pattern, being most significantly associated with reduced extremity fat. Further studies are necessary to determine the relationship between extremity fat loss and increased IMCL in HIV-infected women.

Persistence of lipoatrophy after a four-year long interruption of antiretroviral therapy for HIV1 infection: case report

BACKGROUND

HIV-infected patients on long-term highly active antiretroviral therapy often present peculiar patterns of fat redistribution, referred to as lipodystrophy. In spite of recent investigations, it is not known whether and to what extent the main features of lipodystrophy--that is lipoatrophy of peripheral fat at face, limbs and buttocks, as well as fat accumulation at breasts, abdomen and the dorso-cervical region--can be reversible once clinically manifest.

CASE PRESENTATION

A 35 year old Caucasian HIV infected female developed severe diffuse lipodystrophy while on highly active antiretroviral therapy. A remarkable increase of breast size, fat accumulation at waist, and a fat pad on her lumbar spine were paralleled by progressive and disfiguring lipoatrophy of face, limbs and buttocks. The patient decided to interrupt her therapy after 20 months, with a stably suppressed viremia and a CD4 lymphocyte count > 500/microL. She could carry on a safe treatment interruption for longer than 4 years. Most sites of fat accumulation switched to nearly normal appearance, whereas lipoatrophy was substantially unchanged at all affected sites.

CONCLUSION

our observation provides pictorial evidence that lipoatrophy may not be reversible even under ideal circumstances. Therefore, strategies to prevent lipoatrophy should be considered when defining therapeutic regimens for HIV infected patients, especially those at high risk.

Epidural spinal lipomatosis with acute onset of paraplegia in an HIV-positive patient treated with corticosteroids and protease inhibitor: case report

STUDY DESIGN

Case report.

OBJECTIVE

To report a case of HIV-related lipodystrophy with a rapid onset of symptoms from epidural lipomatosis in the wake of protease inhibitor and steroid treatment.

SUMMARY OF BACKGROUND DATA

Symptomatic spinal epidural lipomatosis is considered to be a rare condition usually presenting with slowly progressive cord or nerve root compression. Only 2 cases of spinal lipomatosis in HIV-related lipodystrophy have been reported.

METHODS

We describe the case of a 41-year-old male with HIV who received protease inhibitor medication and had neurologic deficits rapidly develop.

RESULTS

The patient had complete paraplegia develop within 12 hours from admission following a 1-day history of unsteady gait and a 3-day history of leg numbness. After diagnosis of epidural lipomatosis on magnetic resonance imaging, the patient underwent decompressive thoraco-laminectomy. He recovered well and was able to walk by postoperative day 4.

CONCLUSION

It is important to maintain an awareness for the possible association between HIV lipodystrophy and symptomatic epidural lipomatosis.

Management of dyslipidemia in patients with complicated metabolic syndrome

As the prevalence of the metabolic syndrome increases, 2 comorbid conditions--hepatic steatosis and human immunodeficiency virus (HIV) lipodystrophy--have become difficult clinical challenges. Dyslipidemia in patients with nonalcoholic fatty liver disease or nonalcoholic steatohepatitis may improve with use of statins, fibrates, niacin, and thiazolidinediones, but the data are presently very limited. HIV lipodystrophy is associated with a marked risk of coronary artery disease (CAD), and more aggressive management of the dyslipidemia is likely necessary to improve the prognosis.

Lipoatrophic men 44 months after the diagnosis of lipoatrophy are less lipoatrophic but more hypertensive

OBJECTIVES

To identify clinical factors associated with HIV-associated lipoatrophy and to evaluate body composition changes, blood pressure and lipid levels in lipoatrophic subjects 3-4 years after the atrophy diagnosis.

METHODS

Clinical signs of lipoatrophy were assessed in 308 ambulant HIV-positive patients in 2000-2001. Possible clinical risk factors, such as age, gender, race, wasting, duration of HIV infection, presence or absence of AIDS diagnosis, viral load and CD4 count, and detailed information about drug treatment were analysed and explored in a multivariate model. Lipoatrophic white males with triceps skin fold <10 mm were re-examined after 44 months. Signs of lipoatrophy and associated factors, blood pressure, lipid levels, diet and level of exercise at first and second visits were compared.

RESULTS

In the multivariate analysis, significant clinical risk factors for lipoatrophy were weight loss >7 kg compared to normal weight [odds ratio (OR) 3.76; 95% confidence interval (CI) 1.80-7.82; P<0.001], current and/or previous use of stavudine (OR 3.72; 95% CI 1.57-8.83; P=0.003) and duration of HIV infection >80 months (OR 2.28; 95% CI 1.13-4.59; P=0.021). Forty of 47 lipoatrophic white males with skin fold < 10 mm were available for re-examination. Of these, 15 (38%) no longer fulfilled the atrophy diagnosis (P<0.001). The prevalence of arm atrophy fell from 63 to 28% (P=0.001) and facial atrophy from 55 to 43% (P=0.23). Use of stavudine for < 36 months was significantly associated with lipoatrophy reversal (OR 5.00; 95% CI 1.15-21.80; P=0.032), but weight gain and increased CD4 count were not. Prevalence of hypertension increased from 28 to 50% (P=0.035), mean systolic blood pressure from 130+/-14 to 136+/-19 mmHg (P=0.021) and diastolic blood pressure from 82+/-10 to 87+/-12 mmHg (P<0.001). In spite of increased use of lipid-lowering drugs (from two to nine patients), levels of total cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides were unchanged.

CONCLUSIONS

In this study, we found that weight loss >7 kg, use of stavudine and long duration of HIV infection were significant risk factors for clinical lipoatrophy. Clinical lipoatrophy was partly reversible, and <36 months on stavudine was significantly associated with atrophy reversal. The prevalence of hypertension and the yearly increase of mean blood pressure were disturbingly high in these patients. However, the number of patients in this study was limited, and prospective studies in larger cohorts are required to confirm these findings.

Prevalence of fat redistribution and metabolic disorders in human immunodeficiency virus-infected children

In this study we assessed the prevalence of fat redistribution and metabolic disorders in a population of HIV-infected children on antiretroviral treatment. To make associations with epidemiological parameters, clinical-immune status, viral load and highly active antiretroviral therapy (HAART), we performed a cross-sectional study in HIV-infected children. Epidemiological parameters (age, sex, family history), clinical and immune status, viral load, and duration of antiretroviral treatment (ART) and HAART, including protease inhibitors, were recorded. Presence of clinical signs of fat redistribution and lipid, glucose and lactic acid levels were evaluated. A total of 56 HIV-infected children, including 30 boys (54%), aged between 21 months and 18 years (mean 9.5 years) were studied. In all, 49 patients (87.5%) were receiving ART (mean duration 4 years) and 43 (77%) were receiving HAART (mean duration 3.6 years). Fat redistribution or lipodystrophy was present in 14 patients (25%); seven had lipohypertrophy (12.5%), two lipoatrophy (3.5%) and five a mixed pattern (8.9%). Fat redistribution was higher in children older than 11 years (50%). Of the lipodystrophic patients, 71.4% presented hypertriglyceridaemia (> 130 mg/dl) and 57% hypercholesterolaemia (> 180 mg/dl). We found significant associations between lipodystrophy and age, ART and HAART duration and hypertriglyceridaemia ( P < 0.001, 0.002, 0.016 and < 0.001, respectively), but no significant association with sex, family history, clinical or immune status and viral load.

CONCLUSION

The prevalence of lipodystrophy was 25% (95% confidence interval 14.8-34.6) with lipohypertrophy being the commonest pattern. Clinical fat redistribution was significantly associated with older age, duration of antiretroviral treatment and highly active antiretroviral therapy and hypertriglyceridaemia.

Buffalo Hump Seen in HIV-Associated Lipodystrophy is Associated With Hyperinsulinemia But Not Dyslipidemia

Accumulation of dorsocervical fat, or a "buffalo hump" (BH), is commonly reported in adults with HIV-associated lipodystrophy (HIVLD). The pathogenesis underlying this aspect of a syndrome characterized by loss of subcutaneous fat from other body sites is poorly understood. We aimed to identify risk factors for a BH in HIV-infected adults in cross-sectional analyses of 2 HIV-infected ambulatory populations. The first group (Australian Lipodystrophy Prevalence Survey [APS]) consisted of 1348 Australian HIV-infected adults (95% male) irrespective of changes in body composition. The second group (Lipodystrophy Case Definition [LDCD] study) comprised 417 subjects (83% male) with at least 1 reported moderate or severe feature of HIVLD. A BH was reported in 24 (2%) APS subjects and 79 (19%) LDCD study subjects. A BH was not an isolated finding. Patients with a BH had a high prevalence of other features of HIVLD, similar to lipodystrophic patients without a BH, such as facial lipoatrophy reported in 100% and 61% BH-positive subjects from the APS and LDCD study, respectively. In both groups, those with a BH had higher fasting insulin (P<or=0.007), a higher body mass index (P<or=0.003), a higher waist/hip ratio (P<or=0.001), higher limb fat (P<or=0.003), and higher systolic blood pressure (P<0.05). On multivariate analysis, higher serum insulin, systolic blood pressure, age, and duration of exposure to ritonavir were independently associated with a BH in the APS group. In the LDCD group, higher insulin, diastolic blood pressure, and duration of exposure to zidovudine were independently associated with a BH. There was no association between a BH and hyperlipidemia. These data show that a BH is associated with other physical features of the lipodystrophy phenotype and suggest that hyperinsulinemia, a feature common to HIVLD, obesity, and hypercortisolism, is an important component of this phenotype, thus warranting closer monitoring of BH-positive patients for glucose intolerance and diabetes.

Diastasis recti abdominis in HIV-infected men with lipodystrophy

Diastasis recti abdominis is a condition in which the rectus abdominus muscle separates in the midline at the linea alba producing a ventral herniation. We have observed the occurrence of this condition in HIV-infected men attending an osteopathic clinic. Two such cases are described in detail. An apparent association with HIV-associated lipodystrophy syndrome and implications for management are explored.

Fenofibrate is effective in treating hypertriglyceridemia associated with HIV lipodystrophy

OBJECTIVE

To determine the effectiveness of fenofibrate in treating hypertriglyceridemia associated with highly active antiretroviral therapy-associated HIV lipodystrophy syndrome (HLS).

METHODS

The authors recruited from their HIV metabolic clinic 55 adult patients with anthropomorphic changes consistent with HLS together with hypertriglyceridemia. The patients had no prior history of taking lipid-lowering medications and were free of liver and renal disease. They were on various highly active antiretroviral therapy regimens, and these regimens were not altered during the course of the study. Fenofibrate was started at 54 mg a day and the dose increased every 2 weeks to a maximum of 162 mg/day. Fasting lipid concentrations were measured at baseline and 6 months after the intervention.

RESULTS

At baseline, the fasting plasma concentrations of total cholesterol, triglyceride, and high-density lipoprotein (HDL) cholesterol were 259 +/- 11, 886 +/- 172, and 35.7 +/- 2.3 (mean +/- SEM) mg/dL, respectively. After 6 months of fenofibrate treatment, the fasting plasma concentrations were as follows: total cholesterol, 243 +/- 13; triglycerides, 552 +/- 104, and HDL cholesterol, 35.7 +/- 1.8 mg/dL. The decrease in fasting plasma triglyceride concentration was statistically significant (P < 0.05). Fenofibrate was well tolerated, and no subjects dropped out of the study.

CONCLUSION

Fenofibrate is an effective, well-tolerated treatment for hypertriglyceridemia associated with HLS.

Diagnosis and management of body morphology changes and lipid abnormalities associated with HIV Infection and its therapies

Body-shape changes and lipid abnormalities are common metabolic disorders in HIV-infected persons. It is likely that numerous factors contribute to body-morphology changes, including antiretroviral therapy, HIV infection itself, and immune reconstitution under antiretroviral therapy. A recent large cross-sectional investigation, the Fat Redistribution and Metabolism (FRAM) study, suggests that lipoatrophy is the most common feature of body-shape changes. Recent findings suggest modest benefit in reversing fat wasting by switching to abacavir from stavudine or zidovudine but no benefit from rosiglitazone treatment or switching from protease inhibitor to nonnucleoside reverse transcriptase inhibitor therapy. Human growth hormone treatment reduces fat accumulation, but treatment is expensive and gains in this regard are lost when treatment is stopped. Guidelines for treating lipid abnormalities in the non-HIV-infected population generally apply to HIV-infected persons; however, drug-drug interactions and overlapping toxicities between HIV and lipid therapies must be recognized. Although antiretroviral agents can raise lipid levels, there are data to suggest that in the case of cholesterol, HIV therapy reverses HIV infection-induced reductions of all cholesterol subsets. There are conflicting data regarding whether there is increased cardiovascular morbidity and mortality in the HIV-infected population. On balance, it appears that cardiovascular disease due to HIV-associated lipid disorders currently is a relatively infrequent problem, but once that is increasing in magnitude. This article summarizes a presentation by David A. Wohl, MD, at the February 2004 International AIDS Society-USA course in Atlanta.

Metabolic effects of rosiglitazone in HIV lipodystrophy: a randomized, controlled trial

BACKGROUND

Patients with HIV infection who are treated with antiretroviral agents often lose subcutaneous fat and have metabolic abnormalities, including insulin resistance and reduced adiponectin levels, which may be related to disrupted subcutaneous adipogenesis and altered peroxisome proliferator-activated receptor-gamma signaling.

OBJECTIVE

To investigate the effects of rosiglitazone (4 mg/d), a peroxisome proliferator-activated receptor-gamma agonist, in HIV-infected men and women with hyperinsulinemia and lipoatrophy.

DESIGN

A randomized, double-blind, placebo-controlled, 3-month study.

SETTING

University hospital.

PATIENTS

28 HIV-infected men and women with hyperinsulinemia and lipoatrophy.

MEASUREMENTS

Insulin sensitivity measured by euglycemic hyperinsulinemic clamp testing; subcutaneous leg fat area measured by computed tomography; adiponectin, free fatty acid, and lipid levels; and safety variables.

RESULTS

Rosiglitazone, when compared with placebo, improved insulin sensitivity (mean [+/-SD] change, 1.5 +/- 2.1 mg of glucose/kg of lean body mass per minute vs. -0.4 +/- 1.6 mg/kg per minute; P = 0.02), increased adiponectin levels (mean [+/-SD], 2.2 +/- 2.2 micro g/mL vs. 0.1 +/- 1.1 microg/mL; P = 0.006), and reduced free fatty acid levels (mean [+/-SD], -0.09 +/- 0.1 mmol/L vs. 0.01 +/- 0.1 mmol/L; P = 0.02). Mean percentage (+/-SD) of body fat (1.38% +/- 3.03% vs. -0.83% +/- 2.76%; P = 0.03) and subcutaneous leg fat area (2.3 +/- 8.4 cm2 vs. -0.9 +/- 1.9 cm2; P = 0.02) increased significantly with rosiglitazone compared with placebo. Mean total cholesterol levels (+/-SD) also increased with rosiglitazone compared with placebo (0.6 +/- 1.0 mmol/L [25 +/- 37 mg/dL] vs. -0.4 +/- 0.6 mmol/L [-15 +/- 25 mg/dL]; P = 0.007).

LIMITATIONS

The study was relatively small and of short duration.

CONCLUSIONS

The authors demonstrated positive effects of rosiglitazone on lipoatrophy; insulin sensitivity; and metabolic indices, including adiponectin levels, in HIV-infected patients with lipoatrophy and insulin resistance. Peroxisome proliferator-activated receptor-gamma agonists may correct the metabolic abnormalities associated with disrupted adipogenesis in this population. Further studies must determine the clinical utility of such agents in HIV-infected patients.

Benfluorex as a therapeutic option for insulin resistance in HIV lipodystrophy syndrome

BACKGROUND

HIV lipodystrophy syndrome, characterized by a significant excess of visceral adiposity and a reduced subcutaneous fat mass in association with insulin resistance and dyslipidemia, still affects the majority of antiretroviral-treated HIV-infected patients. The therapeutic management of this syndrome has not yet been well established. Benfluorex is known to decrease insulin resistance with no side effects on lactate levels in HIV-negative patients.

METHOD

We conducted an open-label study of benfluorex (150 mg, 2-3 times a day) that was prescribed for 60 HIV-infected patients who were diagnosed with glucose metabolism abnormalities by oral glucose tolerance test (OGTT); 47 of these patients had visceral fat accumulation measured by computed tomography (VAT). Median follow-up was 12 months (interquartile range [IQR] = 6-12 months). The great majority of patients (90%) were treated with at least triple therapy (in 70% the therapy included at least one PI), with a nonsignificant change over the study period.

RESULTS

Added to antiretroviral therapy, benfluorex improved OGTT in 47/60 cases, including total normalization in 34/60 without lactate concentration modification. A trend toward a decrease in VAT distribution was observed (p =.06). No significant difference was observed in subcutaneous fat distribution, although an increase in subcutaneous thigh adipose tissue was observed in 17/47 (36.2%) cases and 6 patients (12.7%) presented both subcutaneous fat increase and VAT decrease.

Metabolic complications associated with HIV protease inhibitor therapy

HIV protease inhibitors were introduced into clinical practice over 7 years ago as an important component of combination antiretroviral drug regimens which in many ways revolutionised the treatment of HIV infection. The significant improvements in prognosis that have resulted from the use of these regimens, combined with the need for lifelong treatment, have increasingly focused attention on the adverse effects of antiretroviral drugs and on the metabolic complications of HIV protease inhibitors in particular. In this review, the cluster of metabolic abnormalities characterised by triglyceride-rich dyslipidaemia and insulin resistance associated with HIV protease inhibitor therapy are considered, along with implications for cardiovascular risk in patients affected by these complications. Toxicity profiles of individual drugs within the HIV protease inhibitor class are examined, as there is an increased recognition of significant intra-class differences both in terms of absolute risk of metabolic complications as well as the particular metabolic phenotype associated with these drugs. Guidelines for clinical assessment and treatment are emphasised, along with pathophysiological mechanisms that may provide a rational basis for the treatment of metabolic complications. Finally, these drug-specific effects are considered within the context of HIV-specific effects on lipid metabolism as well as lifestyle factors that have contributed to a rapidly increasing incidence of similar metabolic syndromes in the general population. These data highlight the importance of individualising patient management in terms of choice of antiretroviral regimen, assessment of metabolic outcomes and use of therapeutic interventions, based on the assessment of baseline (pre-treatment) metabolic status as well as the presence of potentially modifiable cardiovascular risk factors.

Improvement of fat redistribution, insulin resistance and hepatic fatty infiltration in HIV-associated lipodystrophy syndrome by pioglitazone: a case report

HIV-associated lipodystrophy syndrome is a syndrome occurring in HIV-infected patients who were treated with highly-active antiretroviral therapy (HAART), especially regimen containing protease inhibitors. The syndrome consists of fat redistribution, with loss of subcutaneous fat and increase in visceral fat, and metabolic disturbances, including glucose intolerance or overt diabetes and dyslipidemia. No standard treatment has been established for this syndrome. Pioglitazone is an oral antidiabetic agent that acts primarily on adipose tissue to reduce insulin resistance. The authors report a 50-year old HIV-infected woman who developed HIV-associated lipodystrophy syndrome after 3 months of HAART. She had significant weight loss with obvious loss of subcutaneous fat, together with development of hypertension, diabetes and dyslipidemia. After treatment with 30 milligrams of pioglitazone daily, her body weight increased within the first month of treatment. Subcutaneous fat loss was restored. Improvement in glycemic and lipid control was also noted. CT scan of the abdomen revealed that fatty infiltration in the liver was markedly decreased. Visceral fat as assessed by CT scan had also decreased. Pioglitazone appeared to have beneficial effects in this patient.

Distribución anormal de la grasa corporal y tipo de tratamiento antirretroviral como predictores de riesgo de enfermedad cardiovascular en pacientes infectados por el virus de la inmunodeficiencia humana

BACKGROUND AND OBJECTIVE

Dyslipidemia, insulin resistance and body fat redistribution are respectively short and long-term complications of protease inhibitor-containing antiretroviral regimens. To establish whether differences in the type of antiretroviral therapy (protease-containing or protease-sparing) or the presence and severity of body fat redistribution, explained differences in cardiovascular risk, we undertook a cross-sectional study.

PATIENTS AND METHOD

The study was carried out in 219 consecutive HIV-infected patients attending an outpatient HIV clinic between February and April, 2002. Age, sex, smoking status, weight, height, waist circumference, blood pressure, antihypertensive treatment, total cholesterol, HDL cholesterol, triglycerides, and glucose concentrations, in addition to changes in body fat distribution were measured in 31 HIV-infected patients with no antiretroviral therapy, 35 HIV-infected patients treated with protease inhibitor-sparing regimens, and 153 HIV-infected patients treated with protease inhibitor-containing regimens. A ten-year cardiovascular disease risk was estimated according to the Framingham score.

RESULTS

Patients treated with protease inhibitor-containing regimens as well as patients treated with protease inhibitor-sparing agents showed higher concentrations of cholesterol (p < 0.001), triglycerides (p = 0.004), glucose (p = 0.028), and greater changes in body fat distribution (p = 0.001) than patients with no antiretroviral therapy. An abnormal body fat distribution score was more strongly associated (p < 0.001) with the estimated 10-year cardiovascular disease risk than the type of HAART (p = 0.036). Ten-year cardiovascular disease risk increased linearly from 7.48% to 11.16% and to 19.50% in patients with no or mild, moderate and severe lipodystrophy scores, respectively.

CONCLUSIONS

The results of this study encourage the use of cardiovascular preventive strategies in HIV-infected patients with severe lipodystrophy.

Mechanisms and strategies for insulin resistance in acquired immune deficiency syndrome

Abnormalities of glucose regulation, including impaired glucose tolerance and insulin resistance, are often seen among human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy. Insulin resistance in this population may result from antiviral medication directly impairing glucose uptake in the muscle, effects of HIV per se, or indirect effects, such as fat redistribution. Insulin resistance may increase the risk of coronary heart disease among this population of patients, in part by inhibiting normal thrombolysis. The optimal treatment for insulin resistance and impaired glucose intolerance in HIV-infected patients is not known, but preliminary studies have suggested that metformin, an insulin sensitizing agent, improves insulin sensitivity, blood pressure, and waist circumference. Initial studies of thiazolidinediones also suggest the potential utility of such agents to improve insulin sensitivity, decrease hepatic steatosis, and increase subcutaneous fat. Further studies are needed to determine the optimal treatment strategy for insulin resistance in this population.

HIV infection--a risk factor for osteoporosis

Osteopenia and osteoporosis have recently been described as complications of antiretroviral therapy in HIV-infected patients. The advent of highly active antiretroviral therapy in conjunction with improved standard antiviral and antibiotic regimens has dramatically changed the clinical course of HIV infection, resulting in prolonged survival. The pathogenesis and role of each individual medication are poorly understood. Avascular necrosis has also been described in AIDS patients receiving or not receiving antiretroviral therapy. This article is a clinically focused review of the literature on osteopenia, osteoporosis, and mineral metabolism related to HIV infection. In patients with HIV infection, the risks of osteopenia and osteoporosis are not very clear. The suggested risk factors for the development of osteopenia are use of protease inhibitors, longer duration of HIV infection, high viral load, high lactate levels, low bicarbonate levels, raised alkaline phosphatase level, and lower body weight before antiretroviral therapy. There have also been a few case reports of pathologic fractures in AIDS patients with antiretroviral therapy-induced osteopenia and osteoporosis. The underlying mechanism triggering bone loss in HIV-infected patients is unknown. The proinflammatory cytokines tumor necrosis factor and interleukin-6 have been found to be constitutionally produced in increased amounts in HIV-positive individuals, and they may have a role in osteoclast activation and resorption. Serum markers of bone formation are decreased and resorption is increased in patients with advanced clinical disease. Hypocalcemia, hypercalcemia, and abnormalities of the parathyroid hormone axis have been described in HIV infection. Histomorphometric analyses have shown altered bone remodeling in HIV-infected patients when compared with controls. Patients with known risk factors for osteoporosis-advancing age, low body weight, and prolonged duration of HIV infection-and those receiving protease inhibitor treatment should be considered for dual x-ray absorptiometry imaging. If bone mineral density is osteopenic or osteoporotic, then the patient should also be screened for other known medical causes of osteoporosis and consider treatment with a bisphosphonate or, if hypogonadal, testosterone replacement under close monitoring.

Rosiglitazone in the treatment of HAART-associated lipodystrophy--a randomized double-blind placebo-controlled study

Highly active antiretroviral therapy (HAART) is associated with metabolic adverse events such as insulin resistance and lipodystrophy, that is, atrophy of subcutaneous fat and accumulation of intra-abdominal fat. Currently, there is no pharmacological treatment for lipoatrophy. Glitazones, a novel class of insulin-sensitizing anti-diabetic agents, increase subcutaneous fat in patients with type 2 diabetes. There are no controlled studies of glitazones in patients with HAART-associated lipodystrophy (HAL). In this randomized, double-blind, placebo-controlled study, 30 patients with HAL received either rosiglitazone (8 mg daily) or placebo for 24 weeks. Baseline characteristics were compared to a group of 30 age-, sex- and weight-matched HIV-negative controls. At baseline, patients with HAL had 1.8-fold (P<0.001) more intra-abdominal and 2.4-fold (P<0.05) more liver fat than HIV-negative controls, who had 1.8-fold (P<0.001) more subcutaneous fat than the patients. After 24 weeks of treatment, rosiglitazone had no effect on body weight, subcutaneous or intra-abdominal fat (magnetic resonance imaging), total body fat (bioimpedance analysis), anthropometric measurements or serum leptin concentrations (a circulating marker of adipose tissue mass). However, rosiglitazone decreased % liver fat (spectroscopy) and serum insulin concentrations, and normalized liver function tests. During the first 12 weeks of rosiglitazone treatment, serum triglycerides increased from 3.5 +/- 0.5 to 6.5 +/- 2.0 mmol/l (from 310 +/- 44 to 575 +/- 177 mg/dl) (P<0.05) and serum cholesterol from 6.0 +/- 0.4 to 7.8 +/- 0.7 mmol/l (from 232 +/- 15 to 301 +/- 27 mg/dl) (P<0.01). Contrary to data in other patient groups, rosiglitazone did not increase subcutaneous fat in patients with HAL after 24 weeks of treatment. Rosiglitazone seemed to ameliorate insulin resistance judged by the decreased serum insulin concentrations and % liver fat. Rosiglitazone unexpectedly caused significant increases in serum triglyceride and cholesterol concentrations, which must be carefully monitored if glitazones are used in these patients.