Fat distribution in HIV-infected patients reporting truncal enlargement quantified by whole-body magnetic resonance imaging

The use of non-invasive imaging modalities for the assessment of skeletal muscle quantity and quality in people with HIV: A narrative review

BACKGROUND

People with HIV (PWH) are prone to mobility impairments and physical dysfunction, with the loss of skeletal muscle quantity and quality being a major contributor to the dysfunction. Assessment of skeletal muscle is an important component of care for this patient population for early intervention and treatment. The use of non-invasive imaging techniques to evaluate skeletal muscle, such as dual X-ray absorptiometry, computer tomography and magnetic resonance imaging, has increased in popularity in recent years.

PURPOSE

This narrative review synthesizes the use of these techniques and summarizes the associations between outcomes from these imaging modalities and physical function in PWH.

Visceral adiposity in cirrhosis: Association with disease severity and impact of liver transplantation

BACKGROUND

Changes in adipose tissue distribution in liver cirrhosis are poorly characterized and may affect clinical outcomes.

METHODS

Adult liver transplant (LT) January 2008-August 2017 recipients with abdominal MRI within 6 months pre-LT were retrospectively assessed. Visceral adipose tissue, subcutaneous adipose tissue, and skeletal muscle area (cm2) were determined at L3. Visceral-to-subcutaneous adipose tissue ratio (VSR) was used to define relative adipose distribution, stratified by sex. Correlation was tested with Pearson. Body composition measures were compared by Child-Turcotte-Pugh (CTP) class, before and after LT, and evaluated as predictors of clinical outcomes.

RESULTS

A total of 318 patients were studied. Mean age was 56 years, 33.64% were female, and 47.80% had CTP C cirrhosis. CTP C was associated with a 0.42-point increase in VSR compared with CTP A (95% CI = 0.13-0.71, p < 0.01), adjusting for age, sex, diabetes, and HCC. Among the 79 (24.84%) patients with repeat MRI 1-2 years after LT, VSR significantly improved from before LT (1.31 vs. 0.95, p < 0.01). In adjusted analysis, CTP C was associated with a 0.86-point decrease in post-LT VSR compared with pre-LT VSR (95% CI = -1.27 to -0.44, p < 0.01). Body mass index poorly correlated with VSR before and after LT. Elevated pre-LT VSR trended toward an association with a 7.17-point decrease in pre-LT glomerular filtration rate (95% CI = -14.35 to -0.02, p = 0.05), adjusting for CTP C, age, sex, diabetes, hypertension, pre-LT sarcopenia, and hepatocellular carcinoma. Elevated pre-LT VSR did not affect 3-year post-LT mortality (log-rank p = 0.24).

CONCLUSIONS

Poorly represented by body mass index, visceral adiposity is increased in cirrhosis and is associated with CTP class. However, this adipose redistribution may be modifiable by LT.

Changes in Waist Circumference in HIV-Infected Individuals Initiating a Raltegravir or Protease Inhibitor Regimen: Effects of Sex and Race

Background

This study investigates the association of clinical and demographic predictors with abdominal fat gain, measured using waist circumference (WC) and self-reported abdominal size.

Methods

We analyzed data from ACTG A5257, a clinical trial that randomized treatment-naïve HIV-infected participants to 1 of 3 antiretroviral regimens: raltegravir (RAL) or the protease inhibitors (PIs) atazanavir/ritonavir (ATV/r) or darunavir/ritonavir (DRV/r), each in combination with tenofovir disoproxil fumarate/emtricitabine. Associations of treatment and baseline/demographic characteristics with 96-week WC change were assessed using repeated-measures models. Ordinal logistic regression was used to examine the associations of predictors with week 96 self-reported abdominal changes.

Results

The study population (n = 1809) was 76.0% male and predominantly black non-Hispanic (41.9%) and white non-Hispanic (34.1%). Mean baseline WC was 90.6 cm, with an average 96-week increase of 3.4 cm. WC increases were higher in the RAL arm compared with DRV/r (P = .0130). Females experienced greater increases in WC on RAL vs ATV/r than males (P = .0065). Similarly, a larger difference in WC change was found for RAL vs DRV/r for black vs nonblack individuals (P = .0043). A separate multivariable model found that in addition to the treatment regimen, higher baseline viral load and lower CD4+ were also associated with WC increases.

Conclusions

With antiretroviral therapy initiation, higher WC increases in the RAL arm compared with PIs were more pronounced in female and black participants, and a more advanced baseline HIV disease state was a strong predictor of larger abdominal increases. Understanding factors predisposing individuals to abdominal fat gain could inform health management after therapy initiation.

Whole body MRI of the non-human primate using a clinical 3T scanner: initial experiences

With the advent of parallel imaging MRI techniques, whole-body MRI is being increasingly used in clinical diagnosis. However, its application in preclinical research using large animals remains very limited. In the present study, the whole-body MRI techniques for adult macaque monkeys were explored using a conventional clinic 3T scanner. The T1, T2 anatomical images, and MR angiography of adult macaque whole bodies were illustrated. The preliminary results suggest whole-body MRI can be a robust tool to examine multiple organs of non-human primate (NHP) models from head to toe non-invasively and simultaneously using a conventional clinical setting. As NHPs are intensely used in biomedical research such as HIV/AIDS and vaccine discovery, whole body MRI techniques can have a wide range of applications in translational research using NHPs.

Estimation of Body Fat Mass Using Dual-Energy X-Ray Absorptiometry, Bioelectric Impedance Analysis, and Anthropometry in HIV-Positive Male Subjects Receiving Highly Active Antiretroviral Therapy

BACKGROUND

The purpose of this pilot study was to compare estimates of percentage body fat mass (FM) by bioelectric impedance analysis (BIA) and skinfold measurements (SF) with estimates obtained from dual-energy x-ray absorptiometry (DEXA) in 47 HIV-infected male subjects receiving highly active antiretroviral therapy (HAART). As different patterns of abdominal fat accumulation might affect the body FM estimation, correlation and agreement of these methods were also compared in patients with waist to hip ratio (WHR) < or =0.9 and >0.9.

METHODS

Body FM was estimated by BIA and by measuring skinfold thickness at biceps, triceps, and subscapular area, and was compared with DEXA as the reference method using paired t-test.

RESULTS

Estimates by SF were significantly higher and by BIA were significantly lower compared with DEXA for all subjects. This relationship persisted only in those with WHR >0.9. Both BIA and SF correlated significantly with DEXA, but they did not agree. However, both techniques showed a small intermethod bias, and the precision was within the acceptable range. This relationship persisted in those with WHR >0.9. In comparison with measurement by BIA, SF showed poorer agreement (larger bias and error).

CONCLUSION

For population studies and perhaps to monitor changes over time for intervention studies, the bias for both BIA and SF methods is relatively small and errors and precisions are within the acceptable range when compared with DEXA, and thus all 3 techniques can be used for routine monitoring of total body FM in male subjects with HIV infection.

Effect of Recombinant Human Growth Hormone and Rosiglitazone for HIV-Associated Abdominal Fat Accumulation on Adiponectin and other Markers of Inflammation

BACKGROUND/OBJECTIVE

In a previous report of HIV-infected patients with fat redistribution, we found that recombinant human growth hormone (rhGH) therapy reduced visceral adipose tissue (VAT) but increased insulin resistance, and that the addition of rosiglitazone reversed the negative effects of rhGH on insulin sensitivity. In this study, we sought to determine the effects of rhGH and rosiglitazone therapy on an array of inflammatory and fibrinolytic markers.

METHODS

72 patients with HIV-associated abdominal obesity and insulin resistance were randomized to treatment with rhGH, rosiglitazone, the combination of rhGH and rosiglitazone, or placebo for 12 weeks. Subjects with plasma and serum samples available at weeks 0 (n=63) and 12 (n=46-48) were assessed for adiponectin, C-reactive protein, homocysteine, interleukin-1, interleukin-6, tumor necrosis factor alpha, interferon gamma, fibrinogen, plasminogen activator inhibitor-1 antigen, and tissue plasminogen activator antigen.

RESULTS

Treatment with both rosiglitazone alone and the combination of rosiglitazone and rhGH for 12 weeks resulted in significant increases in adiponectin levels from baseline. Adiponectin levels did not change significantly in the rhGH arm alone . There were no significant changes in the other biomarkers among the different treatment groups.

DISCUSSION

In this study of HIV-infected patients with altered fat distribution, treatment with rosiglitazone had beneficial effects on adiponectin concentrations, an effect that was also seen with a combination of rosiglitazone and rhGH. RhGH administration alone, however, did not demonstrate any significant impact on adiponectin levels despite reductions in VAT.

Segmentation and quantification of adipose tissue by magnetic resonance imaging

In this brief review, introductory concepts in animal and human adipose tissue segmentation using proton magnetic resonance imaging (MRI) and computed tomography are summarized in the context of obesity research. Adipose tissue segmentation and quantification using spin relaxation-based (e.g., T1-weighted, T2-weighted), relaxometry-based (e.g., T1-, T2-, T2*-mapping), chemical-shift selective, and chemical-shift encoded water-fat MRI pulse sequences are briefly discussed. The continuing interest to classify subcutaneous and visceral adipose tissue depots into smaller sub-depot compartments is mentioned. The use of a single slice, a stack of slices across a limited anatomical region, or a whole body protocol is considered. Common image post-processing steps and emerging atlas-based automated segmentation techniques are noted. Finally, the article identifies some directions of future research, including a discussion on the growing topic of brown adipose tissue and related segmentation considerations.

The effect of recombinant human growth hormone with or without rosiglitazone on hepatic fat content in HIV-1-infected individuals: a randomized clinical trial

BACKGROUND

Hepatic fat is related to insulin resistance (IR) and visceral adipose tissue (VAT) in HIV+ and uninfected individuals. Growth hormone (GH) reduces VAT but increases IR. We evaluated the effects of recombinant human GH (rhGH) and rosiglitazone (Rosi) on hepatic fat in a substudy of a randomized controlled trial.

METHODS

HIV+ subjects with abdominal obesity and IR (QUICKI≤0.33) were randomized to rhGH 3 mg daily, Rosi 4 mg twice daily, the combination or double placebo. Hepatic fat was measured by magnetic resonance spectroscopy, visceral fat by MRI and IR by frequently sampled intravenous glucose tolerance tests at baseline and week 12.

RESULTS

31 subjects were studied at both time points. Significant correlations between hepatic fat and VAT (r=0.41; P=0.02) and QUICKI (r=0.39; P<0.05) were seen at baseline. IR rose with rhGH but not Rosi. When rhGH treatment groups were combined, hepatic fat expressed as percentage change decreased significantly (P<0.05) but did not change in Rosi (P=0.71). There were no correlations between changes in hepatic fat and VAT (P=0.4) or QUICKI (P=0.6). In a substudy of 21 subjects, a trend was noticed between changes in hepatic fat and serum insulin-like growth factor-1 (IGF-1; P=0.09).

CONCLUSIONS

Hepatic fat correlates significantly with both VAT and IR, but changes in hepatic fat do not correlate with changes in VAT and glucose metabolism. Hepatic fat content is reduced by rhGH but Rosi has no effect. These results suggest an independent effect of GH or IGF-1 on hepatic fat. The study was registered at Clinicaltrials.gov (NCT00130286).

From wasting to obesity, changes in nutritional concerns in HIV/AIDS

Optimal nutrition is an important part of human immunodeficiency virus (HIV) care; to support the immune system, limit HIV-associated complications as well as maintain better quality of life and survival. The presentation and nature of malnutrition in patients with HIV has changed dramatically over the past 30 years from predominantly a wasting syndrome to lipodystrophy and, now, frailty. Nevertheless, we continue to see all 3 presentations in patient care today. The pathogenesis of poor nutrition in HIV-infected patients depends on caloric intake, intestinal nutrient absorption/translocation, and resting energy expenditure, which are features seen in all chronic diseases.

Anthropometric and Nutritional Profile of People Living with HIV and AIDS in India: an Assessment

BACKGROUND

Importance of nutrition in human immunodeficiency virus (HIV) is well-established; however, the information regarding the diet quality of people living with HIV (PLHIV) especially in India is lacking.

OBJECTIVES

The objective of this study is to assess the anthropometric and nutritional profile of Indian PLHIV.

MATERIAL AND METHODS

The study was performed on 400 adult PLHIV registered at the Antiretroviral Center (ART) center in New Delhi, India. Anthropometric data including height, weight, waist, hip, mid arm, and calf circumferences, were collected; 1-day 24-h dietary recall was done to gather nutrient intake from which nutrient adequacy ratios were computed. Mini Nutritional Assessment (MNA) was also conducted.

RESULTS

The mean body mass index (BMI) of the sample was 19.73 ± 3.55 kg/m(2) with around 40% having BMI <18.5 kg/m(2) . All anthropometric measurements were found to correlate positively and significantly with CD4 count (P < 0.05). The sample consumed poor quality of diet as they could not meet even the 2/3(rd) of the Indian Council of Medical Research (2010) requirements for energy, protein, calcium, iron, riboflavin, niacin, folic acid, B12, copper, and zinc. Classification of subjects according to MNA indicated that more than 50% of the sample was at-risk of malnutrition and 34% were malnourished. With 40% of sample having BMI less than normal, 50% at risk of malnutrition together with poor nutrient intakes over a long period of time could contribute to further worsening of the nutritional status.

CONCLUSION

There is a need to develop a database on nutritional profile of PLHIV in India which reinforces the need for development of effective strategies to improve their nutritional status.

HIV-associated lipodystrophy: impact of antiretroviral therapy

In the late 1990s, reports of unusual changes in body fat distribution named 'lipodystrophy' (LD) began to appear in HIV patients mitigating the enormous enthusiasm about improvement of survival and quality of life provided by the combinations of antiretroviral (ARV) drug classes, the so-called highly active antiretroviral therapy (HAART), which had just become available at that time. The objective of this paper is to critically review the literature on LD and to discuss the impact of newer ARV agents, namely atazanavir, darunavir and raltegravir, as well as strategies of the late HAART era, including single-tablet regimens and nucleoside-sparing regimens. Studies in which LD was measured by dual-energy x-ray absorptiometry or by abdominal computed tomography or magnetic resonance imaging scan only, were included. We were unable to identify studies depicting a negative impact of drugs or ARV regimens on limb fat loss. On the contrary, a few studies identified a negative impact of atazanavir/ritonavir or darunavir/ritonavir on trunk fat increase. It should be noted that this anthropometric measure is a poor instrument since it cannot distinguish between subcutaneous and visceral fat. We conclude that presumably the body fat changes currently observed in HIV-infected patients is the net result of competing phenomena: on one side the natural history of lipohypertrophy as a result of HIV and HAART impact, and on the other side the physiological body fat changes observed in the aging population.

Nutrition and the HIV-associated lipodystrophy syndrome

HIV-associated lipodystrophy syndrome (HALS), comprising metabolic and morphological alterations, is a known side effect of highly active antiretroviral therapy (HAART). Evidence for the role of nutrition in the management of the systemic parameters of HALS is currently limited. In the present paper we review the current knowledge base surrounding HALS, focusing particularly on the role of nutrition in mitigating the systemic parameters of the syndrome. Reported prevalence of HALS was found to vary from 9 to 83 % due to lack of a standardised definition, as well as variations in assessment methods and in the study population used. HALS is associated with both morphological (lipoatrophy, lipohypertrophy) and metabolic (dyslipidaemia, glucose intolerance, diabetes, hypertension, endothelial dysfunction and atherosclerosis) alterations, which may occur singly or in combination, and are associated with an increased risk of CVD. HAART-induced adipocyte inflammation, oxidative stress and macrophage infiltration, as well as altered adipocyte function and mitochondrial toxicity, have been shown to be central to the development of HALS. The adipocyte, therefore, represents a plausible target for treatment. Pharmacological and surgical treatment interventions have shown effect. However, their use is associated with numerous adverse effects and complications. Targeted lifestyle interventions may provide a useful alternative for managing HALS owing to their safety and tolerability. A Mediterranean-style diet has been found to be effective in improving the systemic parameters of HALS. Furthermore, the effects of n-3 PUFA supplementation are encouraging and future randomised controlled trials investigating the beneficial effects of n-3 PUFA in HALS are justified.

Recombinant human growth hormone and rosiglitazone for abdominal fat accumulation in HIV-infected patients with insulin resistance: a randomized, double-blind, placebo-controlled, factorial trial

Background

Recombinant human growth hormone (rhGH) reduces visceral adipose tissue (VAT) volume in HIV-infected patients but can worsen glucose homeostasis and lipoatrophy. We aimed to determine if adding rosiglitazone to rhGH would abrogate the adverse effects of rhGH on insulin sensitivity (SI) and subcutaneous adipose tissue (SAT) volume.

Methodology/Principal Findings

Randomized, double-blind, placebo-controlled, multicenter trial using a 2×2 factorial design in which HIV-infected subjects with abdominal obesity and insulin resistance were randomized to rhGH 3 mg daily, rosiglitazone 4 mg twice daily, combination rhGH + rosiglitazone, or double placebo (control) for 12 weeks. The primary endpoint was change in SI by frequently sampled intravenous glucose tolerance test from entry to week 12. Body composition was assessed by whole body magnetic resonance imaging (MRI) and dual Xray absorptiometry (DEXA).

Seventy-seven subjects were randomized of whom 72 initiated study drugs. Change in SI from entry to week 12 differed across the 4 arms by 1-way ANCOVA (P = 0.02); by pair-wise comparisons, only rhGH (decreasing SI; P = 0.03) differed significantly from control. Changes from entry to week 12 in fasting glucose and glucose area under the curve on 2-hour oral glucose tolerance test differed across arms (1-way ANCOVA P = 0.004), increasing in the rhGH arm relative to control. VAT decreased significantly in the rhGH arms (−17.5% in rhGH/rosiglitazone and −22.7% in rhGH) but not in the rosiglitazone alone (−2.5%) or control arms (−1.9%). SAT did not change significantly in any arm. DEXA results were consistent with the MRI data. There was no significant rhGH x rosiglitazone interaction for any body composition parameter.

Conclusions/Significance

The addition of rosiglitazone abrogated the adverse effects of rhGH on insulin sensitivity and glucose tolerance while not significantly modifying the lowering effect of rhGH on VAT.

Trial Registration

Clinicaltrials.gov NCT00130286

Validation of an Elliptical Anthropometric Model to Estimate Visceral Compartment Area

OBJECTIVE

The visceral compartment is a surrogate for visceral adipose tissue. Cross-sectional visceral compartment area (VCA) has been approximated from waist circumference using a circular model. However, the two-dimensional shape of the abdomen is rarely circular. This study validated an elliptical model of cross-sectional total abdominal area (TAA), subcutaneous adipose tissue (SAT) area, and VCA at the L(4)-L(5) level.

RESEARCH METHODS AND PROCEDURES

We analyzed magnetic resonance images (MRIs) at the level of the L(4)-L(5) intervertebral space from 35 subjects with a wide range of abdominal adiposity. Waist circumference, abdominal thickness (midline sagittal diameter), abdominal width (coronal diameter at one-half of abdominal thickness), and abdominal SAT thickness at four sites (front, back, right, and left) were measured from MRI images using an image analysis software. The same anatomical regions were also estimated from anthropometrics purely by geometric formulae of circular and elliptical models. A simple linear regression model was used to interpret the association strength between anthropometric estimates and MRI measures.

RESULTS

Estimated TAA by either model was strongly related to MRI TAA (r(2) = 0.98, p < 0.0001). The SAT and VCA by MRI analysis showed a stronger association with calculation from an elliptical model (r(2) = 0.95 and 0.88, respectively; p < 0.001) than a circular model (r(2) = 0.69 and 0.25, respectively; p < 0.001). The absolute prediction residuals and variances were significantly smaller with an elliptical model than a circular model (p < 0.0001).

DISCUSSION

An elliptical anthropometric model might be superior to a circular model to estimate abdominal SAT and VCA.

Fat redistribution following suction lipectomy: defense of body fat and patterns of restoration

No randomized studies in humans have examined whether fat returns after removal or where it returns. We undertook a prospective, randomized-controlled trial of suction lipectomy in nonobese women to determine if adipose tissue (AT) is defended and if so, the anatomic pattern of redistribution. Healthy women with disproportionate AT depots (lower abdomen, hips, or thighs) were enrolled. Baseline body composition measurements included dual-energy X-ray absorptiometry (DXA) (a priori primary outcome), abdominal/limb circumferences, subcutaneous skinfold thickness, and magnetic resonance imaging (MRI) (torso/thighs). Participants (n = 32; 36 ± 1 year) were randomized to small-volume liposuction (n = 14, mean BMI: 24 ± 2 kg/m(2)) or control (n=18, mean BMI: 25 ± 2) following baseline. Surgery group participants underwent liposuction within 2-4 weeks. Identical measurements were repeated at 6 weeks, 6 months, and 1 year later. Participants agreed not to make lifestyle changes while enrolled. Between-group differences were adjusted for baseline level of the outcome variable. After 6 weeks, percent body fat (%BF) by DXA was decreased by 2.1% in the lipectomy group and by 0.28% in the control group (adjusted difference (AD): -1.82%; 95% confidence interval (CI): -2.79% to -0.85%; P = 0.0002). This difference was smaller at 6 months, and by 1 year was no longer significant (0.59% (control) vs. -0.41% (lipectomy); AD: -1.00%; CI: -2.65 to 0.64; P = 0.23). AT reaccumulated differently across various sites. After 1 year the thigh region remained reduced (0.77% (control) vs. -1.83% (lipectomy); AD: -2.59%; CI: -3.91 to -1.28; P = 0.0001), but AT reaccumulated in the abdominal region (0.64% (control) vs. 0.42% (lipectomy); AD: -0.22; CI: -2.35 to 1.91; P = 0.84). Following suction lipectomy, BF was restored and redistributed from the thigh to the abdomen.

A Comparison of Sonographic Assessments and Clinical Questionnaire in the Diagnosis of HIV-Associated Lipodystrophy

The study evaluated the use of sonographic measurements as an alternative to assessments based on clinical or other imaging techniques for the diagnosis of body-fat abnormalities. The study enrolled 179 HIV-infected patients, 81 (45.3%) of them diagnosed as lipodystrophy (LD)-positive based on a clinical standard questionnaire. Association between clinical LD and sonographic measurements of face, right upper limb, subcutaneous abdomen, and visceral compartments was evaluated by multiple logistic regression. The predicted probability of the logistic model was 0.64, corresponding to a maximum sensitivity of 69.1% (58%-79%), a specificity of 94.9% (88%-98%), and to positive and negative predictive values of 92% (82%-97%) and 79% (70%-86%), respectively. Kappa measure of concordance was 65% (54%-77%). Low sensitivity poses a problem for the use of sonography to detect LD in the clinical routine as a single exam, speaking in favor of the combined use of clinical and sonographic measurements over time.

The effects of intermittent, CD4-guided antiretroviral therapy on body composition and metabolic parameters

OBJECTIVE

To assess the effects of decreased antiretroviral therapy exposure on body fat and metabolic parameters.

DESIGN

Substudy of the Strategies for Management of Anti-Retroviral Therapy study, in which participants were randomized to intermittent CD4-guided [Drug Conservation (DC) group] or to continuous [Viral Suppression (VS) group] antiretroviral therapy.

METHODS

Participants at 33 sites were coenrolled in the Strategies for Management of Anti-Retroviral Therapy Body Composition substudy. Regional fat was assessed annually by whole-body dual-energy X-ray absorptiometry and abdominal computed tomography. Fasting metabolic parameters were assessed at months 4, 8, and annually. Treatment groups were compared for changes in fat and metabolic markers using longitudinal mixed models.

RESULTS

Two hundred and seventy-five patients were randomized to the DC (n = 142) or VS (n = 133) group and followed for a median of 2.0 years. By month 12, limb fat (DC-VS difference 9.8%, 95% confidence interval 3.5-16.1; P = 0.003) and subcutaneous abdominal fat (DC-VS difference 14.3 cm, 95% confidence interval -0.1 to 28.7; P = 0.05) increased in the DC group. There was no treatment difference in visceral abdominal fat (DC-VS difference -2.1%, 95% confidence interval -13.5 to 9.4; P = 0.72). Lipids significantly decreased in the DC group by month 4 and treatment differences persisted throughout follow-up (P < or = 0.001). By 12 months, hemoglobin A1C increased in the DC (+0.3%) and remained stable in the VS group (P = 0.003); the treatment difference remained significant throughout follow-up (P = 0.02).

CONCLUSION

After 12 months, intermittent antiretroviral therapy increased subcutaneous fat, had no effect on visceral abdominal fat, decreased plasma lipids, and increased hemoglobin A1C compared with continuous antiretroviral therapy.

Comparability of echographic and tomographic assessments of body fat changes related to the HIV associated adipose redistribution syndrome (HARS) in antiretroviral treated patients

To assess the comparability of ultrasonographic (US) subcutaneous fat thickness (SFT) measurements in comparison with computed tomography (CT) at reference points (RPs) representative of HIV related adipose redistribution syndrome (HARS) in patients treated with antiretrovirals. US and CT measurements were compared in nine patients with clinical reports of HARS. We obtained the best resolution of facial (at deepest point of Bichat pad), brachial (in the dorsal face of arm) and crural SFT (at mid thigh) by means of minimal transducer pressures avoiding potential biases such as stand off pads pressure on the skin and artefacts due to too abundant quantity of gel. CT scans were obtained in the same RP where US measurements were performed such as identified by means of metallic skin markers. Median US measurement of facial SFT was 8.8 mm (95% CI: 3.1 to 13.4), 3.95 mm (95% CI: 2.62 to 5.84) for brachial SFT and 4 mm (95% CI: 3.4 to 9.4) for crural SFT. Median CT assessments of facial SFT was 8.7 mm (95% CI: 3.5 to 13.5), 4.2 mm (95% CI: 2.6 to 5.88) for brachial SFT and 5 mm (95% CI: 3.9 to 10.3) for crural SFT, with no significant difference at each RP. A linear regression showed good CT/US comparability at each RP, with no significant deviation from linearity (p > 0.10). US shows to be highly comparable with CT, excluding invaliding biases as the transducer pressure on the skin. Given the proven efficacy on the HARS assessments, if well standardized, US could be a reliable method, simpler than CT in the management of body fat changes related to HARS.

Insulin Resistance, Hepatic Lipid and Adipose Tissue Distribution in HIV-Infected Men

Background

A large proportion of HIV-infected patients on antiretroviral medication develop insulin resistance, especially in the context of fat redistribution. This study investigates the interrelationships among fat distribution, hepatic lipid content, and insulin resistance in HIV-infected men.

Methods

We performed a cross-sectional analysis of baseline data from 23 HIV-infected participants in three prospective clinical studies. Magnetic resonance spectroscopy was used to quantify hepatic lipid concentrations. Magnetic resonance imaging was used to quantify whole-body adipose tissue compartments: that is, subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) volumes, as well as the intermuscular adipose tissue (IMAT) subcompartment and the omental-mesenteric adipose tissue (OMAT) and retroperitoneal adipose tissue (RPAT) subcompartments of VAT. The homeostasis model for assessment of insulin resistance (HOMA-IR) was calculated from fasting glucose and insulin concentrations.

Results

Hepatic lipid content correlated significantly with total VAT (r=0.62, P=0.0014), but not with SAT (r=0.053, P=0.81). In univariate analysis, hepatic lipid content was associated with the OMAT (r=0.67, P=0.0004) and RPAT (r=0.53, P=0.009) subcompartments; HOMA-IR correlated with both VAT and hepatic lipid contents (r=0.61, P=0.057 and r=0.68, P=0.0012, respectively). In stepwise linear regression models, hepatic lipid had the strongest associations with OMAT and with HOMA-IR.

Conclusion

Hepatic lipid content is associated with VAT volume, especially the OMAT subcompartment, in HIV-infected men. Hepatic lipid content is associated with insulin resistance in HIV-infected men. Hepatic lipid content might mediate the relationship between VAT and insulin resistance among treated, HIV-infected men.

Metabolic effects of a growth hormone-releasing factor in patients with HIV

BACKGROUND

Visceral adipose tissue accumulates during antiretroviral therapy in many patients who are infected with the human immunodeficiency virus (HIV); this process is associated with an increased cardiovascular risk. We assessed the use of a growth hormone-releasing factor analogue, tesamorelin, to decrease visceral adiposity.

METHODS

We randomly assigned 412 patients with HIV (86% of whom were men) who had an accumulation of abdominal fat to receive a daily subcutaneous injection of either 2 mg of tesamorelin or placebo for 26 weeks. The primary end point was the percent change from baseline in visceral adipose tissue as shown on computed tomography. Secondary end points included triglyceride levels, the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol, the level of insulin-like growth factor I (IGF-I), and self-assessed body image. Glycemic measures included glucose and insulin levels.

RESULTS

The measure of visceral adipose tissue decreased by 15.2% in the tesamorelin group and increased by 5.0% in the placebo group; the levels of triglycerides decreased by 50 mg per deciliter and increased by 9 mg per deciliter, respectively, and the ratio of total cholesterol to HDL cholesterol decreased by 0.31 and increased by 0.21, respectively (P<0.001 for all comparisons). Levels of total cholesterol and HDL cholesterol also improved significantly in the tesamorelin group. Levels of IGF-I increased by 81.0% in the tesamorelin group and decreased by 5.0% in the placebo group (P<0.001). Adverse events did not differ significantly between the two study groups, but more patients in the tesamorelin group withdrew from the study because of an adverse event. No significant differences were observed in glycemic measures.

CONCLUSIONS

Daily tesamorelin for 26 weeks decreased visceral fat and improved lipid profiles, effects that might be useful in HIV-infected patients who have treatment-associated central fat accumulation. (ClinicalTrials.gov number, NCT00123253 [ClinicalTrials.gov] .).

Switching to a protease inhibitor-containing, nucleoside-sparing regimen (lopinavir/ritonavir plus efavirenz) increases limb fat but raises serum lipid levels: results of a prospective randomized trial (AIDS clinical trial group 5125s)

BACKGROUND

Subcutaneous limb fat loss continues to be one the most troubling side effects of long-term antiretroviral regimens. Nucleoside analogues and protease inhibitors (PIs) have been linked to the development of this complication.

METHODS

We evaluated the effects of nucleoside-sparing and PI-sparing regimens on fat distribution, bone mineral density, and metabolic parameters in 62 subjects, who were not selected for lipoatrophy, with advanced HIV (nadir CD4 count <or=200 cells/mm or HIV RNA level >or=80,000 copies/mL) and an undetectable HIV viral load. Participants were randomized to switch their initial successful antiretroviral regimen to open-label lopinavir/ritonavir (LPV/r) at a dose of 533/133 mg twice a day and efavirenz (EFV) at a dose of 600 mg/d (the nucleoside-sparing arm) versus EFV and 2 nucleoside analogues (the PI-sparing arm).

FINDINGS

At week 48, the median change in limb fat in the nucleoside-sparing arm was 562 g (6%, interquartile range [IQR]: -218-1186 g) versus a loss of -242 g (-4%, IQR: -539-452 g) in the nucleoside-containing PI-sparing arm (P = 0.086). At the time of last observation (median = 102 weeks, IQR: 73-152 weeks), a median gain of 782 g (10%, IQR: -380-1168 g) of limb fat was noted in the nonnucleoside arm (n = 22) versus a loss of 850 g (-15%, IQR: -1270 to -526 g) in the nucleoside-containing arm (n = 25; P = 0.002).

INTERPRETATION

The switch to a nucleoside-sparing combination antiretroviral regimen (LPV/r + EFV) was associated with significant improvement in limb fat. These results provide additional evidence that nucleoside analogues are important in the progressive limb fat loss that characterizes antiretroviral treatment and that switching medications can significantly improve this complication. This option has to be carefully balanced with the potential to increase serum lipid levels and the trend to increase virologic failure.

HIV-associated adipose redistribution syndrome (HARS): definition, epidemiology and clinical impact

A segment of the HIV infected population develops abnormal and excessive accumulation of adipose tissue in the trunk, including accumulation of visceral (deep abdominal) adipose tissue. This condition, known as HIV-related adipose redistribution syndrome (HARS), may also be accompanied by fat accumulation in the upper back/neck (dorsocervical region) and/or depletion of subcutaneous adipose tissue from the abdomen, face, limbs, or buttocks. HARS is estimated to occur in up to 32% of patients and is associated with health risks similar to those of metabolic syndrome. Techniques to detect and measure HARS include physician and patient assessments and radiologic or anthropometric methods.

Independent associations of insulin resistance with high whole-body intermuscular and low leg subcutaneous adipose tissue distribution in obese HIV-infected women

BACKGROUND

Obesity and insulin resistance are growing problems in HIV-positive (HIV+) women receiving highly active antiretroviral therapy (HAART).

OBJECTIVE

The objective was to determine the contribution of adipose tissue (AT) enlargement and distribution to the presence of insulin resistance in obese HIV+ women.

DESIGN

Whole-body intermuscular AT (IMAT), visceral AT (VAT), subcutaneous AT (SAT), and SAT distribution (leg versus upper body) were measured by whole-body magnetic resonance imaging. Insulin sensitivity (S(I)) was measured with an intravenous glucose tolerance test in obese HIV+ women recruited because of their desire to lose weight (n=17) and in obese healthy controls (n=32).

RESULTS

The HIV+ women had relatively less whole-body SAT and more VAT and IMAT than did the controls (P<0.05 for all). A significant interaction by HIV status was observed for the relation of total SAT with S(I) (P<0.001 for the regression's slope interactions after adjustment for age, height, and weight). However, relations of IMAT, VAT, and SAT distribution (leg SAT as a percentage of total SAT; leg SAT%) with S(I) did not differ significantly between groups. For both groups combined, the best model predicting a low S(I) included significant contributions by both high IMAT and low leg SAT%, independent of age, height, and weight, and no interaction between groups was observed (overall r(2)=0.44, P=0.0003).

CONCLUSION

In obese HIV+ women, high whole-body IMAT and low leg SAT% distribution are independently associated with insulin resistance.

HIV-associated adipose redistribution syndrome (HARS): etiology and pathophysiological mechanisms

Human immunodeficiency virus (HIV)-associated adipose redistribution syndrome (HARS) is a fat accumulation disorder characterized by increases in visceral adipose tissue. Patients with HARS may also present with excess truncal fat and accumulation of dorsocervical fat ("buffalo hump"). The pathophysiology of HARS appears multifactorial and is not fully understood at present. Key pathophysiological influences include adipocyte dysfunction and an excessive free fatty acid release by adipocyte lipolysis. The contributory roles of free fatty acids, cytokines, hormones including cortisol, insulin and the growth hormone-adipocyte axis are significant. Other potential humoral, paracrine, endocrine, and neural influences are also discussed.

IRM du tissu adipeux abdominal et lipodystrophie VIH, étude cas-témoin

PURPOSE

To characterize intra-abdominal adipose tissue changes in HIV patients with clinical lipodystrophy using a reproducible imaging technique. Materials and methods. 89 HIV patients with clinical lipodystrophy were included. A single axial T1W image was acquired at the mid L4 vertebral level. Two radiologists measured subcutaneous (SAT) and visceral (VAT) adipose tissues using a semi-automated method. Measurements were compared to a matched population (race, sex, age and BMI).

RESULTS

Measurements of abdominal adipose tissue on MRI are reproducible. Three clinical types of lipodystrophy are described in males with increased visceral (VAT) and reduced subcutaneous (SAT) adipose tissues compared to control subjects. Two clinical types of lipodystrophy are described in females with increased visceral (VAT) and unchanged subcutaneous (SAT) adipose tissues.

CONCLUSION

MRI with comparison between HIV patients and normal control subjects is a reproducible method to characterize adipose tissue changes of lipodystrophy and evaluate its severity. Evaluation of a adipose tissue distribution in a large control population would be helpful to the study of metabolic disorders.

Uridine Supplementation for the treatment of Antiretroviral Therapy-Associated Lipoatrophy: A Randomized, Double-Blind, Placebo-Controlled Trial

Background

Highly active antiretroviral therapy (HAART) is associated with loss of subcutaneous fat (lipoatrophy) presumably due to mitochondrial toxicity of nucleoside reverse transcriptase inhibitors. In vitro, uridine abrogates thymidine analogue-induced toxicity in adipocytes.

Methods

A total of 20 patients with HAART-associated lipoatrophy were randomized to receive either a dietary uridine supplement (36 g three times a day for 10 consecutive days/month) or placebo, for 3 months. Body composition was measured using dual energy X-ray absorptiometry, magnetic resonance imaging and proton spectroscopy. Data are mean ± standard error of mean.

Results

The mean increases in limb fat (880 ±140 versus 230 ±270 g; P<0.05), intra-abdominal fat (210 ±80 versus -80 ±70 cm3; P<0.05) and total body fat (1,920 ±240 versus 240 ±520 g; P<0.01) were significantly greater in the uridine than in the placebo group. Within the uridine group, the changes from baseline to 3 months were statistically significant in total limb fat ( P<0.001), intra-abdominal fat ( P<0.05) and total body fat ( P<0.001). The proportion of limb fat to total fat increased from 18% to 25% ( P<0.05) in the uridine group. Liver fat content and lean body mass remained unchanged in both groups. High-density lipoprotein-cholesterol concentrations decreased in the uridine and increased in the placebo group, whereas fasting serum insulin concentrations did not change. Uridine supplementation was well tolerated and the virological effect of HAART was not affected.

Conclusion

Uridine supplementation significantly and predominantly increased subcutaneous fat mass in lipoatrophic HIV-infected patients during unchanged HAART.

Body composition and metabolic effects of a diet and exercise weight loss regimen on obese, HIV-infected women

HIV has classically been a wasting disease. However, in the United States, obesity is increasingly common among HIV-infected individuals receiving effective antiviral treatment. The risks of obesity are unclear in HIV, although the increased prevalence of diabetes and cardiovascular disease in the presence or absence of obesity causes growing concern. This study aimed to assess the effects of weight loss (through energy restriction combined with aerobic and resistance exercise) on body composition, body fat distribution, resting energy expenditure, quality of life (QOL), strength and fitness, and metabolic risk factors in obese, HIV-infected women. Eighteen HIV-infected women with a body mass index of 30 or more completed a 12-week weight loss program. Before and after the intervention, body composition and fat distribution by dual energy x-ray absorptiometry and whole-body magnetic resonance imaging, resting energy expenditure by indirect calorimetry, QOL, strength, and fitness were measured. Insulin sensitivity by intravenous glucose tolerance test and circulating cardiovascular risk factors (including lipids, tissue plasminogen activator, and plasminogen activator inhibitor 1) were measured in a subset (n = 9). Daily food intake and total body weight decreased (mean +/- SD) by 3195 +/- 477 kJ and 6.7 +/- 4.2 kg, respectively. Weight lost was 95.5% fat by dual energy x-ray absorptiometry or 6.2 L of subcutaneous adipose tissue, 0.7 L visceral adipose tissue, and 0.8 L skeletal muscle by magnetic resonance imaging. Resting energy expenditure fell approximately 419 kJ, strength and fitness increased by 28.9% +/- 18.5% and 36.8% +/- 41.6%, respectively, and QOL improved in 11 of 13 dimensions. There was significant insulin resistance in the subset with metabolic measurements at baseline, and at follow-up there was no improvement in fasting glucose, insulin, or insulin sensitivity, nor was there any change in fasting lipids, tissue plasminogen activator, or plasminogen activator inhibitor 1. There was no significant change in CD4 count or HIV viral load. In conclusion, moderate weight loss achieved by a short-term program of diet and exercise in obese HIV-positive women appears safe and induces loss of adiposity in both the subcutaneous adipose tissue and visceral adipose tissue regions. Despite reduced food intake, weight and fat loss, as well as improvements in strength, fitness, and QOL, the lack of improvement in metabolic parameters suggests that additional interventions may be necessary to reduce the risk of diabetes and cardiovascular disease in this population.

Fat distribution in women with HIV infection

OBJECTIVE

Both peripheral fat loss and central fat gain have been reported in women with HIV infection. We determined the fat changes that are specific to HIV infection in women.

METHODS

HIV-infected and control women from the study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM) were compared. Lipoatrophy or lipohypertrophy was defined as concordance between participant report of fat change and clinical examination. Whole-body magnetic resonance imaging measured regional adipose tissue volumes. The relationship among different adipose tissue depots was assessed. Factors associated with individual depots were analyzed using multivariate linear regression.

RESULTS

HIV-infected women reported more fat loss than controls in all peripheral and most central depots. Peripheral lipoatrophy was more frequent in HIV-infected women than controls (28% vs. 4%, P < 0.001), whereas central lipohypertrophy was similar (62% vs. 63%). Among HIV-infected women, those with central lipohypertrophy were less likely to have peripheral lipoatrophy (odds ratio, 0.39; 95% confidence interval, 0.20 to 0.75, P = 0.006) than those without central lipohypertrophy. On magnetic resonance imaging, HIV-infected women with clinical peripheral lipoatrophy had less subcutaneous adipose tissue (SAT) in peripheral and central sites and less visceral adipose tissue (VAT) than HIV-infected women without peripheral lipoatrophy. Compared with controls, HIV-infected women had less SAT in the legs, regardless of the presence or absence of lipoatrophy. However, those without lipoatrophy had more VAT and upper trunk SAT than controls. Use of the antiretroviral drug stavudine was associated with less leg SAT but was not associated with VAT. The use of highly active antiretroviral therapy, however, was associated with more VAT.

CONCLUSIONS

Peripheral lipoatrophy occurs commonly in HIV-infected women but is not associated with reciprocally increased VAT or trunk fat.

Recombinant human growth hormone therapy in HIV-associated wasting and visceral adiposity

This article reviews the clinical data on recombinant human growth hormone therapy of body composition abnormalities in HIV-infected patients. Short-term recombinant human growth hormone therapy at pharmacologic doses modestly increases total body weight and lean body mass in patients with HIV wasting, resulting in improvements in physical capacity and quality of life. Short-term recombinant human growth hormone therapy has a clear dose-dependent impact on trunk and visceral fat in HIV-infected patients with central fat accumulation, resulting in improvements in perception of body image and a beneficial effect on lipid parameters. Recombinant human growth hormone therapy is also accompanied by dose-dependent side effects related to fluid retention and increased insulin resistance. The optimal treatment strategy, maintenance dose and duration of treatment have not been identified.

Mixed patterns of changes in central and peripheral fat following initiation of antiretroviral therapy in a randomized trial

INTRODUCTION

Although peripheral fat loss is a consistent feature of HIV-associated lipodystrophy, less is known about whether changes in central and peripheral fat occur in tandem or independently over time. We examined intraindividual changes in dual-energy x-ray absorptiometry (DEXA) and anthropometry data over 64 weeks after initiation of antiretroviral therapy (ART).

METHODS

In ACTG 384, ART-naive subjects were randomized to receive didanosine and stavudine or zidovudine and lamivudine plus efavirenz, nelfinavir, or both. In the metabolic substudy A5005S (N= 329), waist, hip, thigh, and arm circumferences were measured in triplicate. DEXA scanning was performed in 157 subjects.

RESULTS

Individual changes in limb and trunk fat at week 64 correlated positively (R =.72, P <.001). Most subjects had directionally concordant changes in limb and trunk fat (36% gained and 32% lost in both regions). In 26%, trunk fat increased while limb fat decreased, whereas the reverse occurred in only 6% (P <.001). Changes in waist and hip circumferences also correlated positively (R =.62, P <.001). The proportion of subjects with waist/hip ratio more than .95 (men) or .90 (women) was 34% at baseline and 47% at week 64 (P =.003). In those who developed increased waist/hip ratio, 76% had increased waist circumference.

CONCLUSIONS

Individual results obtained by both anthropometry and DEXA show diverse patterns of fat gain and loss over 64 weeks after initiation of ART, but changes tended to occur in the same direction. Increased waist/hip ratio was predominantly associated with increased waist circumference. There was no evidence that central fat accumulation and peripheral fat loss are linked in most subjects.

Leptin and Adiponectin in the HIV Associated Metabolic Syndrome: Physiologic and Therapeutic Implications

Leptin and adiponectin represent two newly discovered adipose tissue derived hormones with important roles in energy homeostasis and insulin resistance. Their interrelations with the manifestations of the HIV associated metabolic syndrome and specific somatomorphic changes i.e. fat redistribution is reviewed. A synopsis of published studies is presented and the potential role of leptin and adiponectin is discussed. We have described an association of the HIV metabolic syndrome with a state of reduced insulin sensitivity due to adiponectin deficiency. The metabolic syndrome is also accompanied by leptin deficiency in lipoatrophic subjects and possibly by a leptin resistance state in lipohypertrophic patients. Adiponectin and / or leptin therapy in a manner similar to other leptin deficiency states may assist in the future management of such patients.

CD4+ Cell Count, Viral Load, and Highly Active Antiretroviral Therapy Use Are Independent Predictors of Body Composition Alterations in HIV-Infected Adults: A Longitudinal Study

BACKGROUND

To understand the concurrent effects of human immunodeficiency virus (HIV) infection, the immune system, and antiretroviral therapy on body composition alterations, we examined annualized composition changes in HIV-infected adults who were receiving stable antiretroviral therapy.

METHODS

With use of data from the Nutrition For Healthy Living Study, we performed multivariate analyses using longitudinal models to evaluate the relationship of CD4+ cell count, viral load, and highly active antiretroviral therapy (HAART) or antiretroviral therapy (ART) with changes in trunk and extremity composition for 110 men and 42 women who provided data relating to 194 study intervals (i.e., intervals of time between 2 assessment visits). Of these intervals, 165 involved HAART use (89.7% involved protease inhibitor-based regimens), and 29 did not involve HAART use. Patients receiving HAART or ART (who had continuous use during the interval) were compared with HAART- or ART-naive subjects.

RESULTS

The median length of intervals between visits was 12.9 months (interquartile range, 12.1-17.6 months). In models adjusted for HAART or ART use, baseline CD4+ cell count was positively associated with increased trunk fat (mean increase per year, 2.3% per 100 cells/mm3; 95% confidence interval [CI], 0.7%-3.9%]) and, in men, with increased extremity fat (mean increase per year, 1.8% per 100 cells/mm3; 95% CI, 0.6%-3.0%). Increase in CD4+ cell count predicted increased extremity lean mass (mean increase per year, 0.6% per 100 cells/mm3; 95% CI, 0.05%-1.1%). Higher baseline viral load predicted fat loss (trunk fat loss per year, -5.0% per log10 copies/mL; 95% CI, -9.4% to -0.7%; extremity fat loss per year, -3.4% per log10 copies/mL; 95% CI, -6.1% to -0.6%), as did zidovudine use (trunk fat loss per year, -10.8%; 95% CI, -20.4% to -1.4%; extremity fat loss per year, -4.9%; 95% CI, -9.8% to -0.01%). HAART use independently predicted decreased bone mineral content (extremity bone mineral content loss per year, -1.6%; 95% CI, -3.1% to -0.08%) but did not predict changes in fat or lean mass. Receipt of protease inhibitor-based HAART predicted a -1.9% decrease in extremity bone mineral content per year (95% CI, -3.6% to -0.2%), and zidovudine use predicted a -2.6% decrease in trunk bone mineral content per year (95% CI, -4.4% to -0.8%).

CONCLUSIONS

Baseline viral load, CD4+ cell count, and change in CD4+ cell count predicted alterations in trunk fat, extremity fat, and lean mass. HAART use and zidovudine use were associated with bone loss, and zidovudine use was associated with fat loss, but HAART use was not associated with fat mass changes.

Fat distribution in men with HIV infection

OBJECTIVE

Both peripheral fat loss and central fat gain have been reported in HIV infection. Which changes are specific to HIV were determined by comparison with control subjects and the associations among different adipose tissue depots were determined.

METHODS

Cross-sectional analysis of HIV-positive and control men from the study of Fat Redistribution and Metabolic Change in HIV Infection. Lipoatrophy or lipohypertrophy was defined as concordance between participant report of change and examination. Regional adipose tissue volume was measured by magnetic resonance imaging (MRI).

RESULTS

HIV-positive men reported more fat loss than controls in all peripheral and most central depots. Peripheral lipoatrophy was more frequent in HIV-positive men than in controls (38.3% vs. 4.6%, P < 0.001), whereas central lipohypertrophy was less frequent (40.2% vs. 55.9%, P = 0.001). Among HIV-positive men, the presence of central lipohypertrophy was not positively associated with peripheral lipoatrophy (odds ratio = 0.71, CI: 0.47 to 1.06, P = 0.10). On MRI, HIV-positive men with clinical peripheral lipoatrophy had less subcutaneous adipose tissue (SAT) in peripheral and central sites and less visceral adipose tissue (VAT) than HIV-positive men without peripheral lipoatrophy. HIV-positive men both with and without lipoatrophy had less SAT than controls, with legs and lower trunk more affected than upper trunk. Use of the antiretroviral drugs stavudine or indinavir was associated with less leg SAT but did not appear to be associated with more VAT; nevirapine use was associated with less VAT.

CONCLUSION

Both peripheral and central subcutaneous lipoatrophy was found in HIV infection. Lipoatrophy in HIV-positive men is not associated with reciprocally increased VAT.

The Protease Inhibitor Transfer Study (PROTRA 1): abacavir and efavirenz in combination as a substitute for a protease inhibitor in heavily pretreated HIV-1-infected patients with undetectable plasma viral load

OBJECTIVES

The aim of the study was to evaluate the safety and efficacy of abacavir (ABC) and efavirenz (EFV) instead of a protease inhibitor (PI) in HIV-1-infected subjects treated with two nucleoside reverse transcriptase inhibitors (NRTIs) and one PI with undetectable viral loads (< 50 HIV -1 RNA copies/mL). To be eligible for inclusion, patients had to have a history of viral load < 400 copies/mL for at least 3 months and had to be naive to treatment with nonnucleoside reverse transcriptase inhibitors (NNRTIs) and ABC, but multiple pretreatment and treatment failure were allowed.

DESIGN

An open-label, single-centre pilot study of duration 48 weeks was conducted. ABC was added to the original treatment with two NRTIs and one PI at baseline, and at week 6 the PI was replaced by EFV. At each study visit, CD4 cell count, viral load [measured by polymerase chain reaction (PCR)] and clinical chemistry were measured. Fasting blood samples were taken at baseline and at weeks 12, 24, 36 and 48 to measure levels of cholesterol [high-density lipoprotein (HDL)/low-density lipoprotein (LDL)], triglycerides, insulin and C-peptide. Additionally, an oral glucose tolerance test (OGTT) was performed. A bioelectric impedance analysis (BIA) and a single slice abdominal and mid-thigh computed tomography (CT) scan were carried out to assess changes in body composition.

RESULTS

Thirty patients were included in the study. Three patients experienced ABC-hypersensitivity and one patient demonstrated virological failure caused by nonadherence. At week 48, all remaining patients had viral loads < 50 copies/mL with stable CD4 counts. The fasting metabolic parameters and abdominal fat distribution remained unchanged.

CONCLUSIONS

In heavily pretreated patients, ABC and EFV in combination provide an effective, simplified and well-tolerated alternative to PI treatment.

A comparison of abdominal subcutaneous adipose tissue pattern in obese and lean HIV-infected women

Cells from the superficial and deep subcompartments of the abdominal subcutaneous adipose tissue (SAT) compartment have distinct metabolic activities in vitro. The effect of differing energy balance on the relative in vivo sizes of these subcompartments has not been reported. We retrospectively investigated the effects of obesity and leanness on the relative amounts of superficial and deep SAT in the bulky posterior abdominal adipose tissue in HIV(+) women. We studied the baseline results of MRI scans in 32 obese and 28 lean HIV-infected women. We also compared the change in response to specific interventions. Abdominal MRI slices were obtained at the L4-L5 and L2-L3 intervertebral spaces and were divided into anterior and posterior halves. The posterior portions were further subdivided into deep (PDSAT) and superficial layers (PSSAT) based on tissue planes visible on the MRI. Fat areas in adjacent landmark levels at the trochanter and anterior superior iliac spine were also obtained. PDSAT was larger at L4-L5 than at L2-L3 in both the lean and obese groups. PDSAT was larger than PSSAT at L4-L5 in obese women, and there was preferential loss of PDSAT in obese women who completed a 12-wk energy-deficit diet and exercise program. The contents of PDSAT and PSSAT did not differ in the lean group, and proportional increases in both SAT subcompartments were noted in response to weight gain. In summary, obesity is associated with a preferential increase in PDSAT and greater loss in PDSAT after weight loss. This study defines distinct metabolism responses in fat subcompartments.

Relation of leptin pulse dynamics to fat distribution in HIV-infected patients

BACKGROUND

HIV-infected patients are affected by changes in fat distribution, ie, significant losses of subcutaneous fat in association with metabolic abnormalities.

OBJECTIVE

The objective was to investigate the relation between leptin secretion and subcutaneous fat loss in HIV-infected patients.

DESIGN

We investigated leptin pulse dynamics, measured every 20 min overnight from 2000 to 0800 in 41 HIV-infected patients with a mean (+/-SEM) age of 42.7 +/- 1.1 y and body mass index (in kg/m(2)) of 24.7 +/- 0.4 and in 20 healthy control subjects (age: 42.8 +/- 1.8 y; body mass index: 24.6 +/- 0.5). Leptin pulse variables were compared with total body fat, abdominal subcutaneous fat, and abdominal visceral fat in univariate and multivariate regression analyses.

RESULTS

The number of leptin pulses was not significantly different between the HIV-infected and control subjects. Subcutaneous fat correlated significantly with mean leptin secretion (r = 0.72, P <0.0001), leptin pulse amplitude (r = 0.62, P <0.0001), and leptin nadir (r = 0.62, P <0.0001) in the HIV-infected patients. In stepwise regression modeling, subcutaneous fat (P <0.0001), but not visceral fat, was significantly associated with leptin secretion (overall R(2) for the model = 0.57, P <0.0001) in the HIV-infected patients. For each 1-cm(2) decrease in abdominal subcutaneous fat area, leptin decreased by 0.044 ng/mL when visceral fat was controlled for. Subcutaneous fat was also significantly related to leptin in the control subjects.

CONCLUSIONS

This is the first study to investigate the relation between fat distribution and leptin pulse dynamics in HIV-infected patients. There was a significant reduction in leptin secretion with subcutaneous fat loss in this population.

Lipodystrophies: rare disorders causing metabolic syndrome

Recent advances in the understanding of the molecular basis of genetic lipodystrophies have promoted understanding of how adipose tissue disorders can cause the metabolic syndrome and its complications. These discoveries hold promise for elucidating pathways and mechanisms by which common disorders of obesity cause metabolic complications. Novel therapeutic approaches for patients with lipodystrophies also may have implications for treatment of the metabolic syndrome in patients with regional adiposity. This article reviews these recent advances in our knowledge of the clinical features, metabolic abnormalities, and pathogenetic or other bases of various types of lipodystrophies.

What is HIV-associated lipodystrophy? Defining fat distribution changes in HIV infection

PURPOSE OF REVIEW

The prevalence of lipodystrophy in HIV infection reported in the early literature has varied widely due in part to the different methods used in assessing and defining lipodystrophy in studies. There remains a lack of clarity regarding whether the peripheral lipoatrophy and central lipohypertrophy initially described in HIV infection are a result of separate mechanisms or a single mechanism. We review the current methods used to assess and define lipodystrophy in HIV infection; the prevalence and incidence of lipodystrophy reported in the recent HIV literature; and future directions in elucidating the morphologic changes associated with HIV infection.

RECENT FINDINGS

Different methods of assessing and defining lipodystrophy continue to lead to varying prevalence and incidence rates in recent large cross-sectional and prospective studies. Recent studies that include a predominantly HIV-uninfected comparison group and utilize bi-directional surveys to describe fat loss and fat gain in both peripheral and central body sites suggest that there is an HIV-associated lipoatrophy that affects both peripheral and central sites. In one study that used objective measures to quantify fat such as magnetic resonance imaging, HIV-associated subcutaneous lipoatrophy appeared to predominate when compared with a healthy control group.

SUMMARY

Peripheral and central lipoatrophy affecting subcutaneous fat is emerging as the dominant morphologic change associated with HIV infection when compared with those without known HIV infection. Studies of lipodystrophy in HIV infection should focus on lipoatrophy using direct measures of fat when possible.

Increased systemic and adipose tissue cytokines in patients with HIV-associated lipodystrophy

The lipodystrophy syndrome (adipose tissue redistribution and metabolic abnormalities) observed with highly active antiretroviral therapy (HAART) during human immunodeficiency virus (HIV) infection may be related to increased proinflammatory cytokine activity. We measured acute cytokine (TNF-alpha, IL-6, leptin), glycerol, and lactate secretion from abdominal subcutaneous adipose tissue (SAT), and systemic cytokine levels, in HIV-infected subjects with and without lipodystrophy (HIVL+ and HIVL-, respectively) and healthy non-HIV controls. Lipodystrophy was confirmed and characterized as adipose tissue redistribution in HIVL+ compared with HIVL- and controls, by dual-energy X-ray absorptiometry and by whole body MRI. TNF-alpha secretion from abdominal SAT and circulating levels of IL-6, soluble TNF receptors I and II, and insulin were elevated in HIVL+ relative to HIVL- and/or controls, particularly in HIVL+ undergoing HAART. In the HIV-infected group as a whole, IL-6 secretion from abdominal SAT and serum IL-6 were positively associated with visceral fat and were negatively associated with the relative amount of lower limb adipose tissue (P < 0.01). Decreased leptin and increased lactate secretion from abdominal SAT were specifically associated with HAART. In conclusion, increased cytokine secretion from adipose tissue and increased systemic proinflammatory cytokine activity may play a significant role in the adipose tissue remodeling and/or the metabolic abnormalities associated with the HIV-lipodystrophy syndrome in patients undergoing HAART.

Incidence of lipoatrophy and lipohypertrophy in the women's interagency HIV study

OBJECTIVE

To estimate the incidence of lipoatrophy and lipohypertrophy among HIV-infected and HIV-uninfected women from the Women's Interagency HIV Study.

DESIGN

Eight hundred fifteen women with semiannual data on self-report of bidirectional change in body fat, anthropometric measurements, weight, and bioelectric impedance analysis were included in a 30-month incidence analysis.

METHODS

Lipoatrophy and lipohypertrophy in both peripheral (arms, legs, and buttocks) and central (waist, chest, and upper back) sites were defined by self-report of either a decrease or an increase in a body fat region over the previous 6 months that was confirmed by a corresponding change in anthropometric measurement.

RESULTS

Weight and total body fat increased in HIV-uninfected women but remained stable in HIV-infected women over 30 months. Among HIV-infected women, the incidence of peripheral (relative hazard, 2.1; 95% confidence interval [CI], 1.4-3.3) and central (relative hazard, 1.9; 95% CI, 1.2-2.8) lipoatrophy was about double that among HIV-uninfected women, after adjustment for age and race. The incidence of peripheral lipohypertrophy appeared lower among HIV-infected women than among HIV-uninfected women (relative hazard, 0.8; 95% CI, 0.6-1.1), while the incidence of central lipohypertrophy did not differ by HIV status. Of HIV-infected women with 2 of 4 lipodystrophy outcomes, most (81%) had combined peripheral and central lipoatrophy or combined peripheral and central lipohypertrophy. Only 14% of these women had both peripheral lipoatrophy and central lipohypertrophy.

CONCLUSIONS

These prospective data suggest that lipoatrophy, affecting both peripheral and central sites, predominates in HIV-infected women. The simultaneous occurrence of peripheral lipoatrophy and central lipohypertrophy was uncommon.