Association of the polymorphisms of the genes APOC3 (rs2854116), ESR2 (rs3020450), HFE (rs1799945), MMP1 (rs1799750) and PPARG (rs1801282) with lipodystrophy in people living with HIV on antiretroviral therapy: a systematic review

The aim of this study was to perform a systematic review to identify data reported in the literature concerning the association of APOC3 (rs2854116), ESR2 (rs3020450), HFE (rs1799945), MMP1 (rs1799750) and PPARG (rs1801282) polymorphisms with lipodystrophy in people living with HIV (PLWHIV) on antirretroviral therapy. The research was conducted in six databases and the studies were selected in two steps. First, a search was undertaken in the following electronic databases: PubMed, Science Direct, Medline, World Wide Science, Directory of Open Access Journals, Scielo, Lilacs and Medcarib. The titles and abstracts of 24,859 articles were read to select those that match the elegibilty criteria. Five papers that addressed the association of HAART, lipodystrophy and polymorphisms were selected for the review. There was no association between the polymorphisms of the genes APOC3 and PPARG and lipodystrophy. Another study described an association between the variant allele (G) of HFE and protection concerning the development of lipoatrophy (0.02) when compared with the reference allele (C). On the other hand, the variant allele (T) of the ESR2 gene was associated with the development of lipoatrophy (p = 0.007) when compared with the reference allele (C). In addition, the genotype and the variant allele of the gene MMP1 (2G) were associated with lipodystrophy in PLWHIV on HAART (p = 0.0002 and p = 0.0008, respectively). Therefore, further studies with other populations, involving PLWHIV on HAART are necessary to better understand the role of genetic markers, which may be involved in a predisposition to lipodystrophy.

CT Fat Density Accurately Reflects Histologic Fat Quality in Adults With HIV On and Off Antiretroviral Therapy

CONTEXT

Microscopic measurement of adipocyte size is the gold standard for determining adipose tissue (AT) quality. AT density on CT may also reflect adipocyte quality (lower density = poorer quality).

OBJECTIVE

We used abdominal subcutaneous AT (SAT) specimens and CT scans to validate CT SAT density as a marker of SAT quality in adults living with HIV.

SETTING AND DESIGN

Secondary data analysis from completed trial of antiretroviral therapy (ART) initiation (ACTG A5224s). CT abdominal SAT density was measured in HU. SAT specimens were digitally scanned for calculation of mean adipocyte area.

PARTICIPANTS

Participants had SAT biopsy and CT data at baseline (n = 54) and HIV-1 RNA <50 copies per milliliter on ART and biopsy or CT data at week 96 (n = 30).

OUTCOME MEASURES

Spearman correlations and linear regression models adjusting for participant characteristics examined associations between SAT density and adipocyte area.

RESULTS

Baseline median age was 40 years, CD4+ T lymphocyte count 219 cells per cubic millimeter, and body mass index 26.0 kg/m2; 89% were male and 67% white. Median SAT area and density were 199 cm2 and -100 HU. Over 96 weeks, SAT area increased (+18%) and SAT density decreased (-3%). Mean SAT adipocyte area correlated with SAT density (P < 0.01) off and on ART after adjustment for SAT area, age, race, sex, CD4+ T lymphocyte count, and HIV-1 RNA.

CONCLUSIONS

CT SAT density correlates with biopsy-quantified SAT adipocyte size in adults with HIV on and off ART, suggesting that CT is a useful tool for noninvasive assessment of SAT quality.

Metabolic Syndrome and Cardiovascular Risk in HIV-Infected Patients with Lipodystrophy

In this cross-sectional study, we evaluate potential predictors of Metabolic Syndrome (MS) in a group of 54 Caucasian chronically HIV-infected patients with lipodystrophy. According to ATP-III criteria, 22 patients were affected by MS and 32 were not. The mean age of the sample was 41.2 ± 8.6 years, and most patients were males (74.1%); the two groups were homogeneous for gender, age, viro-immunologic status and the duration of antiviral therapy. The independent association between MS and several factors including demographic characteristics, type of highly-active antiviral therapy (HAART), viro-immunologic response, common cardiovascular risk factors (including Framingham scores), and selected cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10 and IL-18), was investigated using stepwise forward logistic regression. At multivariate analysis, the only independent predictors of the metabolic syndrome were triglycerides and IL-18. A10 mg/dL increase in triglycerides corresponds to an adjusted risk ratio for MS of 1.11 (95% IC: 1.04–1.19); and patients in the top tertile of IL-18 (those with IL-18 ≥ 530 pg/L) had more than three times the likelihood of MS, as compared to the bottom and medium fertiles of IL-18 (patients with IL-18 < 530 pg/L). This relationship was not attenuated by the inclusion of any other variable in the multivariate model. However, the association between metabolic syndrome and IL-18 is no longer significant when IL-18 is treated as a continuous variable (trend p = 0.087). Our results on HIV patients with lipodystrophy confirm previous findings on a strong independent association between IL-18 and MS in the general population. Further research is needed to clarify the mechanism of this association and its role in the development of cardiovascular disease in HIV patients.

IL-4 and IL-6 levels and adipose tissue distribution in HIV-1 patients under antiretroviral therapy

PURPOSE

Combined antiretroviral therapy (cART) for the treatment of HIV-1 infection has been associated with complications, including lipodystrophy. Several interleukins have been implicated in the pathology and physiology of lipodystrophy. The present study aimed to compare the levels of IL-4 and IL-6 in HIV-1 patients under cART with and without, clinically and fat mass ratio defined, lipodystrophy and in four different groups of fat distribution: (1) no lipodystrophy; (2) isolated central fat accumulation; (3) isolated lipoatrophy and (4) mixed forms of lipodystrophy.

METHODS

In the present cross-sectional study we evaluated IL-4 and IL-6 levels, insulin resistance and insulin sensitivity indexes in 86 HIV-infected adults under cART.

RESULTS

No significant differences in IL-4 and IL-6 levels between the four groups of body composition were observed. Patients with HOMA-IR >4 presented higher levels of IL-6 and lower levels of IL-4, although without statistical significance. No correlation between IL-6, or IL-4, HOMA-IR and quantitative body fat mass distribution was found.

CONCLUSION

Although there was a tendency for patients with isolated lipoatrophy and isolated fat accumulation to present higher IL-6 levels, these differences were not statistically significant. No differences were found relating IL-4 levels.

Leptin in congenital and HIV-associated lipodystrophy

Leptin is a hormone secreted by adipocytes that regulates energy metabolism via peripheral action on glucose synthesis and utilization as well as through central regulation of food intake. Patients with decreased amounts of fat in their adipose tissue (lipoatrophy) will have low leptin levels, and hypoleptinemic states have been associated with a variety of metabolic dysfunctions. Pronounced complications of insulin resistance, dyslipidemia and fatty liver are observed in patients suffering from congenital or acquired generalized lipodystrophy while somewhat less pronounced abnormalities are associated with human immunodeficiency virus (HIV) and the use of highly active antiretroviral therapy, the so-called HIV-associated lipodystrophy. Previous uncontrolled open-label studies have demonstrated that physiological doses of leptin repletion have corrected many of the metabolic derangements observed in subjects with rare fat maldistribution syndromes such as generalized lipodystrophy. In the much more commonly encountered HIV-associated lipodystrophy, leptin replacement has been shown to decrease central fat mass and to improve insulin sensitivity, dyslipidemia, and glucose levels. The United States Food and Drug Administration has recently granted approval for recombinant leptin therapy for congenital and acquired generalized lipodystrophy, however large, well-designed, placebo-controlled studies are needed to assess long-term efficacy, safety and adverse effects of leptin replacement. In this review, we present the role of leptin in the metabolic complications of congenital and acquired lipodystrophy and discuss current and emerging clinical therapeutic uses of leptin in humans with lipodystrophy.

Lipid metabolism and lipodystrophy in HIV-1-infected patients: the role played by nonnucleoside reverse transcriptase inhibitors

Dyslipidemia and lipodystrophy represent significant healthcare concerns in HIV-infected patients due to their association with diabetes mellitus and increased cardiovascular disease risk. Since the lipid effects of the nonnucleoside reverse transcriptase inhibitors are not well characterized, we systematically summarized the effects of nonnucleoside reverse transcriptase inhibitor treatment on dyslipidemia and lipodystrophy in HIV-1 infection. As with other classes of antiretroviral agents, the nonnucleoside reverse transcriptase inhibitors are associated with lipid changes, although individual agents exhibit differing effects on lipid profiles. Comparative trials have shown that the risk for hypertriglyceridemia is lower with efavirenz than with the use of ritonavir-boosted lopinavir, but there is a greater likelihood of hypercholesterolemia compared to ritonavir-boosted atazanavir. Data also suggest that efavirenz results in greater increases in plasma lipid levels than integrase inhibitors and CC-chemokine-receptor-5 antagonists. Lipid disturbances are less frequent with the newer nonnucleoside reverse transcriptase inhibitors than with efavirenz. However, in most cases, no change in the total:high-density lipoprotein-cholesterol ratio was seen between the efavirenz and comparator groups. Switching from efavirenz to etravirine or rilpivirine, or the integrase inhibitors raltegravir or elvitegravir, resulted in significant reductions in lipid levels. There appears to be minimal potential for efavirenz or rilpivirine to result in development of lipodystrophy. Overall, nonnucleoside reverse transcriptase inhibitors have a smaller impact on plasma lipids than ritonavir-boosted protease inhibitors, with the newer agents exhibiting more favorable lipid profiles than efavirenz. When considering antiretroviral regimens, awareness of the different lipid effect profiles of the third agent is important, without forgetting the critical contribution of the background antiretrovirals.

Altered miRNA processing disrupts brown/white adipocyte determination and associates with lipodystrophy

miRNAs are important regulators of biological processes in many tissues, including the differentiation and function of brown and white adipocytes. The endoribonuclease dicer is a major component of the miRNA-processing pathway, and in adipose tissue, levels of dicer have been shown to decrease with age, increase with caloric restriction, and influence stress resistance. Here, we demonstrated that mice with a fat-specific KO of dicer develop a form of lipodystrophy that is characterized by loss of intra-abdominal and subcutaneous white fat, severe insulin resistance, and enlargement and "whitening" of interscapular brown fat. Additionally, KO of dicer in cultured brown preadipocytes promoted a white adipocyte-like phenotype and reduced expression of several miRNAs. Brown preadipocyte whitening was partially reversed by expression of miR-365, a miRNA known to promote brown fat differentiation; however, introduction of other miRNAs, including miR-346 and miR-362, also contributed to reversal of the loss of the dicer phenotype. Interestingly, fat samples from patients with HIV-related lipodystrophy exhibited a substantial downregulation of dicer mRNA expression. Together, these findings indicate the importance of miRNA processing in white and brown adipose tissue determination and provide a potential link between this process and HIV-related lipodystrophy.

Thiazolidinediones in the treatment of HIV/HAART-associated lipodystrophy syndrome

The treatment of HIV-1 infected patients with HAART has resulted in long-term suppression of viral replication and reduced progression to AIDS. However, the use of HAART has been associated with adverse effects, including metabolic dysregulation and changes in body fat deposition. This syndrome, known as HIV/HAART-associated lipodystrophy syndrome, is characterized by insulin resistance, dyslipidemia, lipodystrophy, and increased visceral adiposity, which contribute to an increased risk of cardiovascular disease amongst these patients. The thiazolidinediones are a class of agonists for the nuclear receptors, the peroxisome proliferator-activated receptor. Since peroxisome proliferator-activated receptor is critically involved in the regulation of insulin sensitivity and lipid metabolism, a number of clinical trials have analyzed whether thiazolidinediones could ameliorate the signs of HIV/HAART-associated lipodystrophy syndrome. Based on these trials, thiazolidinediones appear to up-regulate peroxisome proliferator-activated receptor-dependent genes such as adiponectin, an effect that could have important physiological benefits in the long-term for HIV/HAART-associated lipodystrophy syndrome patients. Critically, many of the studies were of short duration and thus the beneficial effects of thiazolidinediones might have been missed. In addition, the few studies on the thiazolidinedione pioglitazone showed a beneficial effect on limb fat mass that was not associated with a pro-atherogenic lipid profile. Based on these studies, a large-scale clinical trial of pioglitazone use in HIV/HAART-associated lipodystrophy syndrome patients is warranted.

Leptin replacement therapy does not improve the abnormal lipid kinetics of hypoleptinemic patients with HIV-associated lipodystrophy syndrome

Patients with HIV-associated dyslipidemic lipodystrophy (HADL) have characteristic lipid kinetic defects: accelerated lipolysis, blunted fat oxidation and increased hepatic fatty acid reesterification. HADL patients with lipoatrophy also have leptin deficiency. Small or non-randomized studies have suggested that leptin replacement improves glucose metabolism in HADL, with very limited data regarding its effects on the lipid kinetic abnormalities. We performed a randomized, double-blind, placebo-controlled, dose-escalating (0.02 mg/kg/d for two months; 0.04 mg/kg/d for a further two months) study of the effects of metreleptin on lipid kinetics in 17 adults with HADL, hypertriglyceridemia and hypoleptinemia. Rates of lipolysis, intra-adipocyte and intrahepatic reesterification and fatty acid oxidation were measured using infusions of (13)C(1)-palmitate and (2)H(5)-glycerol, and indirect calorimetry. Fasting lipid profiles and glucose and insulin responses to oral glucose challenge were also measured. Metreleptin treatment induced significant, dose-dependent increases in fasting plasma leptin levels. There was no significant change in total lipolysis, net lipolysis, adipocyte or hepatic re-esterification or fatty acid oxidation, or in fasting triglyceride or HDL-C concentrations, with metreleptin treatment. Metreleptin decreased fasting non-HDL-C levels (P<.01) and area-under-the-curve for glucose (P<.05). In hypoleptinemic HADL patients, treatment with metreleptin at 0.02 or 0.04 mg/kg/d does not improve abnormal fasting lipid kinetics, or triglyceride or HDL-C levels. Metreleptin does, however, improve glycemia and non-HDL-C in these patients. These results suggest a dissociation between leptin's effects on glucose metabolism compared to those on lipid kinetics in HADL.

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.

Comparative transcriptional profiling in HIV-infected patients using human stress arrays: clues to metabolic syndrome

Highly active antiretroviral therapy (HAART therapy) for HIV-1 infection has significantly increased the survival and quality of life of patients with this disease. However, in several epidemiological studies the onset of metabolic syndrome is a phenomenon reported to be extremely frequent. In the present study, genes involved in the molecular cascade responsible for the alteration of fat tissue and of lipid and glucose metabolism in patients with HIV-1 infection treated with antiretroviral therapy were identified. Towards this goal, hybridization using Atlas cDNA Expression Arrays allowed simultaneous monitoring of the expression levels of approximately 250 genes and identification of a panel of changes in relation to different therapeutic groups and in the presence of metabolic syndrome, with some genes being up-regulated, while others are down-regulated in the different subgroups of patients. The results of this analysis have shown a panel of transcriptional changes associated with oxidative stress mechanisms that provide a basis for further studies on understanding of mechanisms that, in vivo, are the foundation the metabolic disorders in patients with HIV infection.

Human monocytes accelerate proliferation and blunt differentiation of preadipocytes in association with suppression of C/EBPΑ mRNA

Obesity, type 2 diabetes, and HIV-associated lipodystrophy are associated with abnormalities in adipocyte growth and differentiation. In persons with these conditions, adipose depots contain increased numbers of macrophages, but the origins of these cells and their specific effects are uncertain. Peripheral blood mononuclear cells (PBMC)-derived monocytes, but not T cells, cocultured via transwells with primary subcutaneous preadipocytes, increased proliferation (approximately twofold) and reduced differentiation (~50%) of preadipocytes. Gene expression analyses in proliferating preadipocytes (i.e., prior to hormonal induction of terminal differentiation) revealed that monocytes down-regulated mRNA levels of CCAAT/enhancer binding protein, alpha (C/EBPα) and up-regulated mRNA levels of G0/G1 switch 2 (G0S2) message, genes important for the regulation of adipogenesis and the cell cycle. These data indicate that circulating peripheral blood monocytes can disrupt adipogenesis by interfering with a critical step in C/EBPα and G0S2 transcription required for preadipocytes to make the transition from proliferation to differentiation. Interactions between preadipocytes and monocytes also increased the inflammatory cytokines IL-6 and IL-8, as well as a novel chemotactic cytokine, CXCL1. Additionally, the levels of both IL-6 and CXCL1 were highest when preadipocytes and monocytes were cultured together, compared to each cell in culture alone. Such cross-talk amplifies the production of mediators of tissue inflammation.

Adipose tissue biology and HIV-infection

HIV-1/highly active antiretroviral therapy-associated lipodystrophy syndrome (HALS) is an adipose tissue redistribution disorder characterized by subcutaneous adipose tissue lipoatrophy, sometimes including visceral adipose tissue hypertrophy and accumulation of dorsocervical fat ('buffalo hump'). The pathophysiology of HALS appears to be multifactorial and several key pathophysiological factors associated with HALS have been identified. These include mitochondrial dysfunction, adipocyte differentiation disturbances, high adipocyte lipolysis, and adipocyte apoptosis. These alterations in adipose tissue biology expand to involve systemic metabolism through alterations in endocrine functions of adipose tissue (via disturbed adipokine release), enhanced production of pro-inflammatory cytokines and excessive free fatty-acid release due to lipolysis. The deleterious action of some antiretroviral drugs is an important factor in eliciting these alterations in adipose tissue. However, HIV-1 infection-related events and HIV-1-encoded proteins also contribute directly to the complex development of HALS through effects on adipocyte biology, or indirectly through the promotion of local inflammation in adipose tissue.

Nutritional and metabolic status of HIV-positive patients with lipodystrophy during one year of follow-up

OBJECTIVES

The aim of this prospective study was to compare changes in lipid metabolism and nutritional status after either 6 and 12 months of follow-up in subjects with lipodystrophy syndrome after traditional lifestyle therapy with or without fibric acid analogue intervention (bezafibrate and clofibrate).

METHODS

Food intake, alterations in body composition and metabolic abnormalities were assessed in subjects with lipodystrophy syndrome at the beginning of the study. The nutritional status and metabolic alterations of the subjects were monitored, and the subjects received nutritional counseling each time they were seen. The subjects were monitored either two times over a period no longer than six months (Group A; n = 18) or three times over a period of at least 12 months (Group B; n = 35). All of the subjects underwent nutrition counseling that was based on behavior modification. The fibric acid analogue was only given to patients with serum triglyceride levels above 400 mg/dL.

RESULTS

After six months of follow-up, Group A showed no alterations in the experimental parameters. After twelve months, there was a decrease in serum triglyceride levels (410.4 ± 235.5 vs. 307.7 ± 150.5 mg/dL, p < 0.05) and an increase in both HDLc levels (37.9 ± 36.6 vs. 44.9 ± 27.9 mg/dL, p,0.05) and lean mass (79.9 ± 7.8 vs. 80.3 ± 9.9 %, p < 0.05) in Group B.

CONCLUSION

After one year of follow-up (three sessions of nutritional and medical counseling), the metabolic parameters of the subjects with lipodystrophy improved after traditional lifestyle therapy with or without fibric acid analogue intervention.

The pilot study of DXA assessment in chinese HIV-infected men with clinical lipodystrophy

The aim of this study was to evaluate human immunodeficiency virus (HIV)-infected patient's body composition changes by dual-energy X-ray absorptiometry (DXA) and to analyze factors associated with lipodystrophy (LD). Total-body composition was measured by DXA in HIV-infected men and healthy men. HIV-infected men were divided into LD patients and non-LD patients according to whether they were complicated with LD. Healthy men were selected as controls. Fat mass (FM) of HIV-infected patients correlated negatively with the duration of HIV infection and with the duration of highly active antiretroviral therapy regimen (r(s)=-0.448 and -0.563; p=0.032 and 0.000, respectively). Multiple linear regression results showed that FM had positive correlation with weight and bone mineral content (BMC) and had negative correlation with lean mass (LM). Total body and regional FMs were found to be significantly different among LD patients, non-LD patients, and controls-the lowest in LD patients and the highest in controls (p<0.05). Total body, trunk, and leg BMCs of LD patients were lower than those of controls (p<0.05). Lumbar bone mineral density of LD patients was lower than that of non-LD patients and controls (p=0.04 and 0.007). LM of LD patients was higher than that of non-LD patients, and trunk LM had statistical difference between the 2 groups (p=0.003). Applying DXA to assess HIV-infected patient's body composition changes could provide objective information for physicians to prevent LD and osteoporosis.

Uridine metabolism in HIV-1-infected patients: effect of infection, of antiretroviral therapy and of HIV-1/ART-associated lipodystrophy syndrome

Background

Uridine has been advocated for the treatment of HIV-1/HAART-associated lipodystrophy (HALS), although its metabolism in HIV-1-infected patients is poorly understood.

Methods

Plasma uridine concentrations were measured in 35 controls and 221 HIV-1-infected patients and fat uridine in 15 controls and 19 patients. The diagnosis of HALS was performed following the criteria of the Lipodystrophy Severity Grading Scale. Uridine was measured by a binary gradient-elution HPLC method. Analysis of genes encoding uridine metabolizing enzymes in fat was performed with TaqMan RT-PCR.

Results

Median plasma uridine concentrations for HIV-1-infected patients were 3.80 µmol/l (interquartile range: 1.60), and for controls 4.60 µmol/l (IQR: 1.8) (P = 0.0009). In fat, they were of 6.0 (3.67), and 2.8 (4.65) nmol/mg of protein, respectively (P = 0.0118). Patients with a mixed HALS form had a median plasma uridine level of 4.0 (IC95%: 3.40–4.80) whereas in those with isolated lipoatrophy it was 3.25 (2.55–4.15) µmol/l/l (P = 0.0066). The expression of uridine cytidine kinase and uridine phosphorylase genes was significantly decreased in all groups of patients with respect to controls. A higher expression of the mRNAs for concentrative nucleoside transporters was found in HIV-1-infected patients with respect to healthy controls.

Conclusions

HIV-1 infection is associated with a decrease in plasma uridine and a shift of uridine to the adipose tissue compartment. Antiretroviral therapy was not associated with plasma uridine concentrations, but pure lipoatrophic HALS was associated with significantly lower plasma uridine concentrations.

Effects of insulin-like growth factor (IGF)-I/IGF-binding protein-3 treatment on glucose metabolism and fat distribution in human immunodeficiency virus-infected patients with abdominal obesity and insulin resistance

CONTEXT

HIV-infected patients on antiretroviral therapy are at increased risk for excess visceral adiposity and insulin resistance. Treatment with GH decreases visceral adiposity but worsens glucose metabolism. IGF-I, which mediates many of the effects of GH, improves insulin sensitivity in HIV-negative individuals.

OBJECTIVE

Our objective was to determine whether IGF-I, complexed to its major binding protein, IGF-binding protein-3 (IGFBP-3), improves glucose metabolism and alters body fat distribution in HIV-infected patients with abdominal obesity and insulin resistance.

METHODS

We conducted a pilot, open-label study in 13 HIV-infected men with excess abdominal adiposity and insulin resistance to assess the effect of 3 months of treatment with IGF-I/IGFBP-3 on glucose metabolism and fat distribution. Glucose metabolism was assessed by oral glucose tolerance test and hyperinsulinemic-euglycemic clamp. Endogenous glucose production (EGP), gluconeogenesis, whole-body lipolysis, and de novo lipogenesis (DNL) were measured with stable isotope infusions. Body composition was assessed by dual-energy x-ray absorptiometry and abdominal computed tomography scan.

RESULTS

Glucose tolerance improved and insulin-mediated glucose uptake increased significantly during treatment. EGP increased under fasting conditions, and suppression of EGP by insulin was blunted. Fasting triglycerides decreased significantly in association with a decrease in hepatic DNL. Lean body mass increased and total body fat decreased, whereas visceral adipose tissue did not change.

CONCLUSIONS

Treatment with IGF-I/IGFBP-3 improved whole-body glucose uptake and glucose tolerance, while increasing hepatic glucose production. Fasting triglycerides improved, reflecting decreased DNL, and visceral adiposity was unchanged.

Rosiglitazone improves lipoatrophy in patients receiving thymidine-sparing regimens

OBJECTIVE

Thymidine reverse transcriptase inhibitors (tNRTI) are strong inhibitors of PPAR-gamma and clearly implicated as a cause of lipoatrophy. Thiazolidenediaones (TZD), potent PPAR-gamma agonists, would be expected to be beneficial in HIV lipoatrophy, but prior studies have been conflicting. None specifically excluded the use of tNRTIs. We report the first study in individuals treated with tNRTI-sparing regimens using a TZD for treatment of HIV lipoatrophy.

DESIGN

This double-blind, placebo-controlled study evaluated limb fat in HIV-infected individuals with lipoatrophy who discontinued tNRTI at least 24 weeks prior to enrollment.

METHODS

Individuals were randomized to rosiglitazone vs. placebo for 48 weeks. Dual energy X-ray absorptiometry (DEXA)-scans and fasting metabolic assessments were serially performed.

RESULTS

We enrolled 71 individuals, 17% were female and 51% white. Baseline characteristics were similar between groups except for higher total cholesterol in the placebo group (P = 0.04). At 48 weeks, limb fat (grams) increased significantly (P = 0.02) more in the rosiglitazone than in the placebo group: median (IQR) 448 (138, 1670) vs. 153 (-100, 682), respectively. Of lipids parameters, only total cholesterol increased significantly more in the rosiglitazone group (P = 0.008). Prevalence of metabolic syndrome and total bone mineral density did not change between or within groups.

CONCLUSION

In the absence of tNRTI, rosiglitazone significantly improves lipoatrophy without deleterious effect on bone mineral density. Total cholesterol, but not triglycerides, significantly increased in the rosiglitazone arm. The glitazones may be a promising addition for accelerating fat recovery in individuals who had switched off tNRTI and remain with significant lipoatrophy.

Longitudinal study of body composition of 101 HIV men with lipodystrophy: dual-energy X-ray criteria for lipodystrophy evolution

The aim of this study was to define evolution profiles of body composition among human immunodeficiency virus (HIV)-infected men with lipodystrophy. The design is a retrospective analysis using observational data collected longitudinally. We included 101 HIV-infected men with lipodystrophy managed in routine practice and who had 2 dual energy X-ray absorptiometry scans within a minimum interval of 18 mo. Lipodystrophy was defined as a fat mass ratio (FMR, defined as the ratio of the percentage of the trunk fat mass over the percentage of the lower limbs fat mass) equal or superior to 1.5. Patients were classified in "improved" group (IG: increase of lower limbs fat mass >/= 10%) or "nonimproved" group (NIG). Body composition, immunovirological and epidemiological data were collected and compared between the 2 groups. In the whole population, over a 4-yr period, a significant increase was observed for total fat mass, trunk fat mass, and lower limbs fat mass, whereas total lean mass was stable. Total body mineral density decreased. Fifty-nine patients (IG), less exposed to zidovudine than the NIG, had an increase of lower limbs fat mass higher than 10%. But only 13 (22%) regained a normal distribution of fat mass (FMR < 1.5), showing that lipodystrophy was slowly reversible. Among the NIG, 5 patients (11.9%), less exposed to zidovudine and with a higher mean of viral load, reached an FMR below 1.5. It was mainly because of a loss of trunk fat mass, which could be the sign of a lipodystrophy worsening. Lipodystrophy improved for 58.4% of men. The improvement was very slow. Recovery was observed only in patients with an earlier intervention. No correlation was observed between lipodystrophy and total body bone mineral density. The loss of trunk fat mass without gain of lower limbs fat mass may indicate a worsening of HIV disease.

Fat mass ratio: an objective tool to define lipodystrophy in hiv-infected patients under antiretroviral therapy

Human immunodeficiency virus (HIV) infection and its treatment with antiretroviral therapy (ART) have been associated with lipodystrophy. Different clinical methodologies have been used to define the syndrome. The aim of this study was to propose gender-specific reference values using objective measurements for defining lipodystrophy in HIV-infected patients. Using dual-energy X-ray absorptiometry (DXA), total body composition was analyzed in 221 HIV-infected patients under ART (146 men). We used fat mass ratio (FMR) as the ratio between the percent of the trunk fat mass and the percent of the lower-limb fat mass. One hundred forty patients (63.6%) presented clinically defined lipodystrophy. In men, the optimal cutoff value for the FMR was 1.961 (area under the receiver operating characteristic curve [AUC]: 0.74 [95% confidence interval (CI): 0.66-0.82], p<0.001), with a sensitivity 58.3%, a specificity 83.7%, a positive predictive value (PPV) of 89.6% and a negative predictive value (NPV) of 45.5%. In women, the optimal cutoff value for the FMR was 1.329 (AUC: 0.74 [95% CI: 0.63-0.86], p<0.001), with a sensitivity 51.4%, a specificity 94.6%, a PPV of 90.5%, and an NPV of 66.0%. The FMR evaluated by DXA with the gender-specific cutoffs defined here is an objective way to define HIV-related lipodystrophy.

A rosiglitazone-induced increase in adiponectin does not improve glucose metabolism in HIV-infected patients with overt lipoatrophy

HIV-infected patients on antiretroviral therapy frequently develop changes in body fat distribution and disturbances in glucose metabolism, associated with reduced adiponectin levels. Because adiponectin, principally the high-molecular-weight (HMW) form, has insulin-sensitizing properties, we investigated the effects of an increase in adiponectin on glucose metabolism in HIV-lipodystrophy. In this randomized, double-blind, placebo-controlled trial, we included HIV-1-infected patients with severe lipoatrophy, with an undetectable viral load and who had received neither protease inhibitors nor stavudine for ≥6 mo. Patients were randomized to rosiglitazone [8 mg daily (n = 8)] to increase adiponectin levels or placebo (n = 5) for 16 wk. Peripheral glucose disposal, glucose production, and lipolysis were measured after an overnight fast and during a hyperinsulinemic-euglycemic clamp using stable isotopes. Body composition was assessed by computed tomography and dual-energy X-ray absorptiometry. Although body fat distribution was unaffected, rosiglitazone increased total plasma adiponectin levels by 107% (P < 0.02) and the ratio of HMW to total adiponectin by 73% (P < 0.001). In the placebo group, neither total adiponectin levels (P = 0.62) nor the ratio of HMW to total adiponectin changed (P = 0.94). The marked increase in adiponectin induced by rosiglitazone was not associated with significant changes in basal endogenous glucose production (P = 0.90), basal lipolysis (P = 0.90), insulin-mediated suppression of glucose production (P = 0.17) and lipolysis (P = 0.54) nor with changes in peripheral glucose disposal (P = 0.13). Acknowledging the limited statistical power of our small study, these findings, if confirmed by larger studies, could question the importance of adiponectin in regulating glucose metabolism in HIV-lipodystrophy.

Clinical management of HIV-associated lipodystrophy

PURPOSE OF REVIEW

Lipodystrophy or fat re-distribution, and its associated metabolic abnormalities, are common in HIV patients. The pathogenesis is multifactorial. This article provides an update on the latest findings of the different clinical management strategies that have been utilized in patients with lipodystrophy.

RECENT FINDINGS

Treatment strategies need to be different in those patients with lipoatrophy when compared with patients with central fat accumulation (lipohypertrophy). Most of the treatments studied have produced minimal or modest effects, which are not sustained when the therapy is discontinued. The treatment of associated metabolic abnormalities such as insulin resistance and hyperlipidemia should have similar goals to that in the non-HIV population, but is complicated by the fact that response may be worse and there is a need to consider drug-drug interactions with the antiretrovirals.

SUMMARY

Multiple complex strategies will need to be utilized in these patients to treat the different features seen in lipodystrophy in order to reduce their long-term cardiovascular risk. Further research is also needed to evaluate combination therapies and to identify the underlying mechanisms in order to develop novel therapies for the future.

The effect of rosiglitazone on insulin sensitivity, beta cell function, bone mineral density, and body composition in hiv-positive patients on highly-active antiretroviral therapy (HAART)

Highly active antiretroviral therapy (HAART) leads to lipodystrophy and is associated with detrimental changes in glucose and lipid metabolism. This study investigated the impact of rosiglitazone on insulin sensitivity, beta cell function, bone mineral density, and body composition in HIV+ nondiabetic subjects under HAART. In this randomized, double blind, placebo controlled parallel group study, 40 HIV+ subjects were treated with rosiglitazone 4 mg/day (R, n=23) or placebo (P, n=17) for 6 months. Glucose, insulin and C peptide concentrations were analyzed for assessing insulin sensitivity and secretion. Adiponectin and leptin were evaluated. Body fluid compartments were measured with bioelectrical impedance spectroscopy, and bone mineral density and body composition with Dual X Ray absorptiometry. Rosiglitazone improved peripheral insulin sensitivity (+36.7+/-15.7 ml/min/m (2), p=0.03, means+/-SEM), while no change was observed in P (+4.5+/-19.5 ml/min/m (2), p=0.55). Liver insulin resistance, beta cell activity, and hepatic insulin clearance did not change. Plasma adiponectin increased (R: +2.47+/-0.86 microg/ml, p=0.01 vs. P: +0.45+/-0.60, p=0.28). Rosiglitazone had no influence on body composition, fat distribution and bone mineral density but expanded extra-cellular fluid volume in HIV infected persons (R: +0.50+/-0.21 l, p=0.02 vs. P: 0.10+/-0.25 l, p=0.32). Lipid metabolism in P remained unchanged, in R total cholesterol and LDL cholesterol levels increased significantly (p<0.05). Rosiglitazone treatment resulted in improved peripheral insulin sensitivity with increased circulating adiponectin in HIV patients under HAART. No effect was seen on body fat distribution, bone mineral density, and weight. These side effects and their potential for cardiac risk must be weighed against the beneficial effects on glucose metabolism.

Effects of ritonavir on adipocyte gene expression: evidence for a stress-related response

To understand the molecular mechanisms underlying the development of dyslipidemia and lipodystrophy that occurs after administration of aspartic acid protease inhibitors, we examined transcriptional profiles using cDNA microarrays in 3T3-L1 adipocytes exposed to 10 micromol/l ritonavir for 2-21 days. The expression levels of approximately 12,000 transcripts were assessed using the MgU74Av2 mouse microarray chip. Ritonavir altered gene expression of inflammatory cytokines, stress response genes localized to endoplasmic reticulum, oxidative stress genes, apoptosis-related genes, and expression of genes involved in cell adhesion and extracellular matrix remodeling. Microarray analysis also identified a novel gene downregulated by ritonavir, Cidea, whose expression levels may affect free-fatty acid metabolism. These changes suggest a unique, stress-related pattern in adipocytes induced by chronic exposure to the protease inhibitor, ritonavir.

Low-dose physiological growth hormone in patients with HIV and abdominal fat accumulation: a randomized controlled trial

CONTEXT

Antiretroviral therapy can be associated with visceral adiposity and metabolic complications, increasing cardiovascular risk, and reduced growth hormone (GH) secretion may be a contributing factor.

OBJECTIVE

To investigate the effects of low-dose physiological GH administration on body composition, glucose, and cardiovascular parameters in patients with human immunodeficiency virus (HIV) having abdominal fat accumulation and relative GH deficiency.

DESIGN, SETTING, AND PATIENTS

A randomized, double-blind, placebo-controlled trial of 56 patients with HIV, abdominal fat accumulation, and reduced GH secretion (peak GH <7.5 ng/mL) conducted at a US academic medical center between November 2003 and October 2007.

INTERVENTION

Patients were randomly assigned to receive either subcutaneous GH or matching placebo titrated to the upper quartile of normal insulinlike growth factor 1 (IGF-1) range for 18 months. Starting dose was 2 microg/kg/d and increased to maximum dose of 6 microg/kg/d (average dose, 0.33 mg/d).

MAIN OUTCOME MEASURES

Change in body composition assessed by computed tomographic scan and dual-energy x-ray absorptiometry. Secondary outcomes included glucose, IGF-1, blood pressure (BP), and lipids. Treatment effect was the difference in the change between GH and placebo groups, using all available data.

RESULTS

Fifty-five patients (26 with GH and 29 with placebo) were included in the safety analyses and 52 patients (25 with GH and 27 with placebo) were included in the efficacy analyses. Visceral adipose tissue area (treatment effect [last-value-carried-forward analysis {n = 56}, -19 cm(2); 95% confidence interval {CI}, -37 to -0.3 cm(2)], -19 cm(2); 95% CI, -38 to -0.5 cm(2); P = .049); trunk fat (-0.8 kg; 95% CI, -1.5 to -0.04 kg; P = .04); diastolic BP (-7 mm Hg; 95% CI, -11 to -2 mm Hg; P = .006); and triglycerides (-7 mg/dL, P = .002) improved but 2-hour glucose levels on glucose tolerance testing increased in the GH group vs the placebo group (treatment effect, 22 mg/dL; 95% CI, 6-37 mg/dL; P = .009). The IGF-1 levels increased (treatment effect, 129 ng/mL; 95% CI, 95-164 ng/mL; P < .001). Adverse events were not increased for GH vs placebo (23%; 95% CI, 9%-44% vs 28%; 95% CI, 13%-47%; P = .70).

CONCLUSIONS

In HIV-associated abdominal fat accumulation and relative GH deficiency, low-dose GH received for 18 months resulted in significantly reduced visceral fat and truncal obesity, triglycerides, and diastolic BP, but 2-hour glucose levels on glucose tolerance testing were increased.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00100698.

[Corporal fat distribution and lipidic and glicemic profiles of HIV-infected patients]

The aims of this study were to describe anthropometric data and glycemic and lipidic profiles of HIV-infected patients treated or not with antiretrovirals (ARV) drugs, and to assess association between these drugs and body composition changes, lipid and glucose homeostasis disturbances. There were 176 patients included (133 ARV-treated patients and 43 ARV-naïve). The patients were submitted to clinical evaluation, laboratorial analysis, ultrasonographic measurements, bioelectrical impedance analysis and skin folds thickness measurements. The ARV-treated group showed higher waist-to-hip ratio (p= 0.0002), higher intra-abdominal fat thickness measured by ultrasonography (p= 0.003) and lower bicipital (p= 0.01) and tricipital (p= 0.0002) skin folds. This group also showed higher triglyceride (p= 0.0002), total cholesterol (p= 0.00007), HDL cholesterol (p= 0.009), glucose measurements one hour (p= 0.01) and two hours (p= 0.001) after dextrose load, higher levels of fasting insulin (p= 0.03) and higher HOMAR index (p= 0.02). The antiretroviral drugs are associated with increased visceral fat and decreased peripheral fat pads. Beside that, these drugs are associated with atherogenic lipid profile and insulin resistance, two independent risk predictors of cardiovascular disease.

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.

Therapy insight: Body-shape changes and metabolic complications associated with HIV and highly active antiretroviral therapy

Increasingly effective therapies for HIV infection are now available. These treatments, referred to collectively as highly active antiretroviral therapy, comprise various combinations of anti-HIV drugs from different drug classes. Recently, a range of metabolic complications have emerged as important toxicities in treated patients. Complications present as abnormalities of body-fat mass distribution in association with an often significant dyslipidemia and glucose homeostasis dysregulation. The body-shape changes, manifesting as peripheral lipoatrophy or central lipohypertrophy, can have a negative impact on quality of life and consequently on adherence to treatment. The combination of central lipohypertrophy, dyslipidemia and insulin resistance is associated with accelerated rates of atherosclerosis and other potentially significant long-term effects. The pathogenesis of these effects is complex and is still being actively investigated. Possible contributing factors relate to host characteristics, HIV viral parameters and specific effects of anti-HIV drugs on adipose-tissue biology and on intermediary metabolism. Management of these complications involves manipulation of the anti-HIV drugs using an understanding of their particular effects on lipid and glucose metabolism, in association with standard therapeutic interventions. Individualized approaches, taking into consideration quality-of-life issues, and assessment of potential cardiovascular risks, are now an important component of effective care of HIV-infected patients.

Considering metabolic issues when initiating HIV therapy

Patients with HIV infection and their clinicians are increasingly considering the risk of metabolic complications when choosing HIV therapies. Fear of the potential metabolic consequences of antiretroviral agents may lead some to delay HIV therapy and threaten medication adherence once treatment is initiated. Until recently, there has been limited objective study of the relative contributions of specific antiretrovirals and particular combinations of these drugs to dyslipidemia and body fat changes; in lieu of data, unsupported perceptions regarding the links between therapies and these metabolic complications have predominated. Over the past year, a number of comparative clinical trials have clarified the association between exposure to antiretrovirals and lipid and fat disorders and, in some cases, have yielded results that challenge our perceptions regarding the causes of these complications.

Short-term overfeeding increases resting energy expenditure in patients with HIV lipodystrophy

BACKGROUND

HIV lipodystrophy and other lipodystrophy syndromes are characterized by extensive loss of subcutaneous adipose tissue. Lipodystrophy syndromes are also associated with increased resting energy expenditure (REE). This hypermetabolism may be an adaptive response to an inability to store triacylglycerol fuel in a normal manner.

OBJECTIVE

This study was done to determine whether REE increases significantly after short-term overfeeding in patients with HIV lipodystrophy.

DESIGN

REE was measured in HIV-infected patients with lipodystrophy (n = 9) and in HIV-infected (n = 10) and healthy (n = 9) controls after 3 d on a eucaloric diet and again after 3 d on a diet of similar composition but increased in calories by 50%.

RESULTS

After 3 d of eucaloric feeding, REE was significantly higher in patients with HIV lipodystrophy [33.2 +/- 0.27 kcal/kg lean body mass (LBM)] than for both HIV-infected and healthy controls (29.9 +/- 0.26 and 29.6 +/- 0.27 kcal/kg LBM, respectively; P < 0.01). Furthermore, after 3 d of overfeeding, REE increased significantly in patients with HIV lipodystrophy but not in the control groups (33.2 +/- 0.27 vs 34.7 +/- 0.27 kcal/kg LBM; P < 0.01). Finally, postprandial thermogenesis did not differ among the groups after a "normal" test meal but tended to be higher in patients with HIV lipodystrophy than in healthy controls after a large test meal.

CONCLUSIONS

Adaptive thermogenesis in the resting component of total daily energy expenditure and in the postprandial period may be a feature of the HIV lipodystrophy syndrome and may be due to an inability to store triacylglycerol fuel in a normal manner.

The role of protease inhibitors in the pathogenesis of HIV-associated insulin resistance: Cellular mechanisms and clinical implications

HIV-associated insulin resistance frequently presents as relative lack of peripheral adipose tissue storage associated with dyslipidemia. This review discusses explanations for the links between acute and subacute abnormalities in glucose metabolism and chronic changes in adipose tissue distribution. Specifically, the molecular mechanisms by which the HIV protease inhibitor class of drugs may affect the normal stimulatory effect of insulin on glucose and fat storage are reviewed. It is proposed that both chronic inflammation from HIV infection and treatment with some drugs in this class trigger cellular homeostatic stress responses with adverse effects on glucose metabolism. The physiologic outcome is such that total energy storage in the adipocytes is decreased, and the remaining adipocytes resist further energy storage. The excess circulating and dietary lipid metabolites, normally "absorbed" by adipose tissue, are deposited ectopically in lean (muscle and liver) tissue where they impair insulin action. This leads to a pathologic cycle of insulin resistance, lipotoxicity and lipoatrophy and a clinical phenotype of body fat distribution with elevated waist-to-hip ratio similar to the metabolic syndrome.

Inhibition of lipolysis stimulates peripheral glucose uptake but has no effect on endogenous glucose production in HIV lipodystrophy

HIV-infected patients with lipodystrophy (HIV lipodystrophy) are insulin resistant and have elevated plasma free fatty acid (FFA) concentrations. We aimed to explore the mechanisms underlying FFA-induced insulin resistance in patients with HIV lipodystrophy. Using a randomized, placebo-controlled, cross-over design, we studied the effects of an overnight acipimox-induced suppression of FFAs on glucose and FFA metabolism by using stable isotope-labeled tracer techniques during basal conditions and a two-stage euglycemic-hyperinsulinemic clamp (20 and 50 mU insulin/m(2) per min, respectively) in nine patients with nondiabetic HIV lipodystrophy. All patients received antiretroviral therapy. Biopsies from the vastus lateralis muscle were obtained during each stage of the clamp. Acipimox treatment reduced basal FFA rate of appearance by 68.9% (95% CI 52.6-79.5) and decreased plasma FFA concentration by 51.6% (42.0-58.9) (both, P < 0.0001). Endogenous glucose production was not influenced by acipimox. During the clamp, the increase in glucose uptake was significantly greater after acipimox treatment compared with placebo (acipimox: 26.85 micromol x kg(-1) x min(-1) [18.09-39.86] vs. placebo: 20.30 micromol x kg(-1) x min(-1) [13.67-30.13]; P < 0.01). Insulin increased phosphorylation of Akt Thr(308) and glycogen synthase kinase-3beta Ser(9), decreased phosphorylation of glycogen synthase (GS) site 3a + b, and increased GS activity (percent I-form) in skeletal muscle (P < 0.01). Acipimox decreased phosphorylation of GS (site 3a + b) (P < 0.02) and increased GS activity (P < 0.01) in muscle. The present study provides direct evidence that suppression of lipolysis in patients with HIV lipodystrophy improves insulin-stimulated peripheral glucose uptake. The increased glucose uptake may in part be explained by increased dephosphorylation of GS (site 3a + b), resulting in increased GS activity.

Increased resting energy expenditure, fat oxidation, and food intake in patients with highly active antiretroviral therapy-associated lipodystrophy

Highly active antiretroviral therapy (HAART) is associated with metabolic adverse events such as lipodystrophy in human immunodeficiency virus (HIV)-infected patients. The objective of the present study was to evaluate the effects of HAART-associated lipodystrophy on resting energy expenditure and caloric intake. In this cross-sectional study we compared resting energy expenditure (REE) and energy intake in 30 HAART-treated patients with lipodystrophy (HAART+LD+) with 13 HAART-treated patients without lipodystrophy (HAART+LD-). REE was measured using indirect calorimetry, and energy intake was recorded as a 3-day diary of food intake. REE (5,180+/-160 vs. 4,260+/-150 J/min, P<0.01) and also REE expressed per fat-free mass (86+/-1 vs. 78+/-2 J.kg fat-free mass-1.min-1, P<0.01) were significantly higher in the HAART+LD+ than the HAART+LD- group. Rate of lipid oxidation was significantly higher in the HAART+LD+ than the HAART+LD- group. Total energy and fat intakes were significantly increased in the HAART+LD+ compared with the HAART+LD- group. These results imply that HAART-associated lipodystrophy is associated with increased REE and lipid oxidation and with increased caloric and fat intake.

Effects of high-intensity endurance and resistance exercise on HIV metabolic abnormalities: a pilot study

The purposes of this pilot study were to examine the effects of a 16-week supervised high-intensity combined endurance and resistance exercise training program on HIV-associated metabolic abnormalities (abdominal adiposity, dyslipidemia, and insulin resistance) and to explore methodological issues related to the design and implementation of the research protocol in preparation for a randomized controlled trial. A one-group pretest-posttest design was used, with outcomes measured at baseline and within 1 week after the conclusion of the training program. The exercise program consisted of 16 weeks (preceded by a 2-week phase-in period) of three endurance sessions (20 min at 70%-80% of VO (2max)) and two resistance sessions per week (one set of 8-10 repetitions at 80% of one-repetition maximum on seven exercises). Outcome measures included lipid levels (total, high-density lipoprotein, and low-density lipoprotein cholesterol and triglycerides), visceral and subcutaneous adipose area measured by electron beam tomography, fat and lean mass of trunk and limbs measured by dual-energy X-ray absorptiometry, and insulin sensitivity measured by the homeostatic model assessment. Nine participants were recruited, 5 of whom completed the intervention and had pretest and posttest data available for analyses. Aerobic capacity and strength improved over the course of the intervention. Statistically significant decreases were found for total and trunk fat mass (1,324.9 g [+/-733.6] and 992.8 g [+/-733.6], respectively). Triglycerides decreased by 59 mg/dL (+/-69.88), and insulin sensitivity decreased by 15.7% (+/-41.7%), neither of which was a statistically significant change. Results suggest that further testing of the combined exercise intervention in a randomized controlled design is warranted.

Altered expression of nucleoside transporter genes (SLC28 and SLC29) in adipose tissue from HIV-1-infected patients

BACKGROUND

Nucleoside transporter proteins (NTs) encoded by members of the SLC28 and SLC29 gene families contribute to nucleoside and nucleobase recycling but also modulate extracellular adenosine levels and thus adenosine-regulated metabolic targets.

METHODS

We have examined the expression pattern of NT-encoding genes in human adipose tissue and we have further analysed whether the mRNA related to these genes show changes in their amounts associated with either HIV-1 infection, highly active antiretroviral therapy (HAART) or development of HIV-1-associated lipodystrophy syndrome (HALS).

RESULTS

Human adipocytes express SLC28A1, SLC28A2 and SLC28A3 (encoding hCNT1, hCNT2 and hCNT3, respectively) and SLC29A1 and SLC29A2 (encoding hENT1 and hENT2, respectively). HIV-1 infection, prior to HAART and HALS development, is associated with the upregulation of the mRNA levels of the genes encoding hCNT1, hCNT3 and hENT2. The increase in the mRNA amounts for the former two genes may be due to the action of tumour necrosis factor-alpha (TNF-alpha), a cytokine with enhanced expression in adipose tissue following HIV-1 infection, as the effect is also observed in human adipocytes in culture after treatment with TNF-alpha. HAART and HALS development are associated with the upregulation of the mRNA levels encoding hCNT2 and hENT1, and further enhancement of hCNT1, hCNT3 and hENT2 gene expression.

CONCLUSIONS

These data suggest that selected genes of the SLC28 and SLC29 families are not only targets of HIV-1 infection, but might also contribute to the development of adipose tissue alterations leading to lipodystrophy.

Pathogenesis of lipodystrophy and lipid abnormalities in patients taking antiretroviral therapy

HIV-associated lipodystrophy, arising as a result of long-term therapy with antiretroviral medications, is a complex syndrome characterized by changes in regional fat mass, dyslipidemia, and insulin sensitivity that, once established, is difficult to reverse. The syndrome arises largely as a result of effects of nucleoside reverse transcriptase inhibitors and protease inhibitors on lipid metabolism. Many of these effects have their basis at a molecular level with nucleoside reverse transcriptase inhibitors linked to inhibition of mitochondrial RNA transcription, depletion of mitochondrial DNA and mitochondrial dysfunction and protease inhibitors linked with adipocyte toxicity through interference with the function of essential cellular transcription factors such as sterol regulatory element binding protein 1c. These molecular toxicities can affect non-adipose tissues, and together with secondary effects on lipid and glucose metabolism of changes in body fat mass, help to contribute to the dyslipidemia and insulin resistance characteristic of this syndrome. This review will summarize what is known of the molecular mechanisms underlying HIV-associated lipodystrophy. A greater understanding of these mechanisms is essential if effective therapeutic options are to be found.

Relationship of mitochondrial DNA depletion and respiratory chain activity in preadipocytes treated with nucleoside reverse transcriptase inhibitors

OBJECTIVE

To study the impact of adipocyte differentiation on nucleoside reverse transcriptase inhibitor (NRTI)-mediated mitochondrial DNA (mtDNA) depletion and to correlate mtDNA depletion with the activity of the respiratory chain complexes.

METHODS

We studied adipocyte phenotype, viability, differentiation (CCAAT/enhancer-binding protein [C/EBP]-alpha and peroxisome proliferator-activated receptor [PPAR]-gamma expression), adiponectin production, mtDNA content, activity of respiratory chain complexes and citrate synthase activity in 3T3-L1 adipocytes. Cells were exposed to zidovudine (6 microM or 180 microM), stavudine (3 microM or 90 microM), and zalcitabine (0.1 microM or 3 microM) at different developmental stages for up to 2 months.

RESULTS

Zidovudine and stavudine impaired adiponectin production in vitro at therapeutic Cmax concentrations, but none of the tested NRTIs had a negative impact on adipocyte differentiation or led to mtDNA depletion at these concentrations. Susceptibility of preadipocytes to mtDNA depletion was dependent on cell proliferation and differentiation, and mtDNA depletion occurred only after exposure to high drug concentrations. Under these conditions, stavudine led to up to 80% mtDNA depletion in both dividing and differentiating preadipocytes, whereas zidovudine affected mtDNA only in the differentiating cells. Despite mtDNA depletion by NRTIs, activity of the respiratory chain complexes was found to be unimpaired.

CONCLUSIONS

We found mtDNA depletion in adipocytes but proliferation and/or differentiation of the cells seems to be a prerequisite for this phenomenon. Depletion of mtDNA up to 80%, however, was not associated with impaired respiratory chain activity in 3T3-L1 preadipocytes.

Liver triglyceride content in HIV-1-infected patients on combination antiretroviral therapy studied with 1H-MR spectroscopy

OBJECTIVE

To carry out an exploratory evaluation of liver triglyceride content in HIV-1-infected patients receiving highly active antiretroviral therapy (HAART) using proton magnetic resonance spectroscopy and to study how both the treatment itself and the biochemical and physiological variables in which the treatment causes alterations are related to liver fat content.

METHODS

Intracellular hepatic triglyceride content was determined in 29 HIV-1-infected patients on their first HAART regime by means of localized water-unsuppressed single voxel proton spectra. Other measurements were body mass index, waist-to-hip ratio, lipodystrophy assessment and a detailed blood biochemical analysis. The relationship between intracellular hepatic triglycerides and relevant descriptive, treatment and biochemical variables was studied by correlation and regression analysis.

RESULTS

Intrahepatic triglycerides were detected in 58.6% of the patients and 13.8% showed a triglyceride content compatible with liver steatosis. Many variables (body mass index, waist-to-hip ratio, cumulative exposure to PIs, lactate, insulin, insulin resistance measured by the homeostasis model assessment method [HOMA-R index], pH, total triglycerides, high density lipoprotein cholesterol and very low density lipoprotein [VLDL] cholesterol) correlated individually with the amount of triglycerides. Stepwise multiple regression analysis showed that the combination of insulin or HOMA-R index and VLDL cholesterol accounted for up to 50.2% of the triglyceride liver variance. A positive relationship was found between the concomitant presence of the metabolic syndrome components (insulin resistance, dyslipidaemia and central obesity) and intrahepatic triglyceride content.

CONCLUSIONS

The study showed that intrahepatic triglyceride deposit appears to be a frequent feature of HIV-1-infected patients receiving HAART. A coherent multifactorial combination of biochemical and physiological factors associated with the deposit suggested that cumulative exposure to PIs might be a possible trigger event.

Is oxygen a key factor in the lipodystrophy phenotype?

BACKGROUND

The lipodystrophic syndrome (LD) is a disorder resulting from selective damage of adipose tissue by antiretroviral drugs included in therapy controlling human-immunodeficiency-virus-1. In the therapy cocktail the nucleoside reverse transcriptase inhibitors (NRTI) contribute to the development of this syndrome. Cellular target of NRTI was identified as the mitochondrial polymerase-gamma and their toxicity described as a mitochondrial DNA (mtDNA) depletion resulting in a mitochondrial cytopathy and involved in fat redistribution. No mechanisms offer explanation whatsoever for the lipo-atrophic and lipo-hypertrophic phenotype of LD. To understand the occurrence we proposed that the pO2 (oxygen partial pressure) could be a key factor in the development of the LD. For the first time, we report here differential effects of NRTIs on human adipose cells depending on pO2 conditions.

RESULTS AND DISCUSSION

We showed that the hypoxia conditions could alter adipogenesis process by modifying expression of adipocyte makers as leptin and the peroxisome proliferator-activated receptor PPARgamma and inhibiting triglyceride (TG) accumulation in adipocytes. Toxicity of NRTI followed on adipose cells in culture under normoxia versus hypoxia conditions showed, differential effects of drugs on mtDNA of these cells depending on pO2 conditions. Moreover, NRTI-treated adipocytes were refractory to the inhibition of adipogenesis under hypoxia. Finally, our hypothesis that variations of pO2 could exist between adipose tissue from anatomical origins was supported by staining of the hypoxic-induced angiopoietin ANGPTL4 depended on the location of fat.

CONCLUSION

Toxicity of NRTIs have been shown to be opposite on human adipose cells depending on the oxygen availability. These data suggest that the LD phenotype may be a differential consequence of NRTI effects, depending on the metabolic status of the targeted adipose tissues and provide new insights into the opposite effects of antiretroviral treatment, as observed for the lipo-atrophic and lipo-hypertrophic phenotype characteristic of LD.

Switching strategies to improve lipid profile and morphologic changes

Metabolic alterations and body fat changes are well-recognized limitations of protease inhibitor-based regimens. Strategies of replacing protease inhibitors with nonnucleoside reverse transcriptase inhibitors or abacavir have been shown to improve metabolic abnormalities, particularly by decreasing cholesterol and triglyceride levels, and reducing cardiovascular risk. The various therapeutic options show differences in efficacy, tolerability, and metabolic outcomes. Abacavir seems to be better tolerated, at least in the only randomized trial in which the three options were compared face-to-face, but it is associated with higher virologic failure in patients with prior suboptimal nucleoside therapy. Nonnucleoside reverse transcriptase inhibitors, particularly nevirapine, result in a better lipid profile with a greater increase in HDL cholesterol and in the HDUtotal cholesterol ratio, one of the most important parameters associated with a reduction in cardiovascular risk. Efavirenz has been associated with increased triglyceride levels in some studies. Although protease inhibitor compounds as a family have been linked to metabolic and body fat alterations, new drugs such as atazanavir seem to be associated with a more favorable lipid profile. Lipoatrophy is a stigmatizing complication in HIV-infected patients receiving HAART. There is strong evidence suggesting a prominent role of thymidine analogs, mainly stavudine, in its development. Substitution of stavudine or zidovudine for abacavir or tenofovir partially improves peripheral fat loss. In addition, the lipid profile significantly improves. Finally, although the extended use of non-thymidine nucleoside analogs and the development of new families of antiretroviral drugs will probably result in a lower impact in lipids and morphologic changes, many patients are currently under treatment with these compounds. In this setting, switching strategies may be useful to minimize clinical and psychological consequences, improving the quality of life of HIV-infected patients treated with HAART.

Multidisciplinary approach to the treatment of metabolic and morphologic alterations of HIV-related lipodystrophy

BACKGROUND

Treatment for metabolic and morphologic alterations in HIV-related lipodystrophy include medical therapy, physical exercise, and surgical interventions.

METHOD

We assessed the efficacy and safety of a comprehensive multidisciplinary approach for treating morphological and metabolic alterations of the lipodystrophy syndrome in consecutive patients attending the Metabolic Clinic (MC) of the University of Modena and Reggio Emilia who had at least 2 evaluations over a 48-week period. 245 patients were evaluated: 143 (62.4%) were men, 74 (36.1%) presented with lipoatrophy, 10 (4.9%) with fat accumulation, 93 (45%) with mixed forms, 24 (11.3%) had hypercholesterolemia (LDL >160 mg/dL), 87 (38%) had hypertriglyceridemia (TG >150 mg/dL), 13 (5.7%) had diabetes (glucose >126 mg/dL), and 78 (44%) had insulin resistance (HOMA-IR >4).

RESULTS

At follow-up, a significant improvement was observed in both objective and subjective variables. Anthropometric improvement was observed in waist to hip ratio, waist circumference, and right and left cheek dermal thickness measurements. A nonsignificant improvement was observed in fat and lean regional mass by DEXA; CT showed improvement in visceral and subcutaneous adipose tissue. Glucose, HOMA-IR, total cholesterol, and APO B improved. Subjective variables improved in aesthetic satisfaction.

CONCLUSION

We conclude that the medical and surgical interventions proposed in this multidisciplinary therapeutic approach are efficacious and safe in the management of lipodystrophy.

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.

Adipose tissue lipin expression levels distinguish HIV patients with and without lipodystrophy

OBJECTIVE

Lipodystrophy is the major complication of antiretroviral therapy in HIV-infected patients. Its pathophysiology is not well understood, but has been linked to antiadipogenic effects of antiretroviral drugs. Lipin represents a newly characterized protein that is critical for adipocyte differentiation, and lipin deficiency leads to lipodystrophy in the mouse. The objective of this study was to determine whether altered lipin gene expression is associated with HIV lipodystrophy in humans.

DESIGN

We measured lipin mRNA levels in subcutaneous abdominal and femoral-gluteal adipose tissue biopsies from HIV-infected patients with or without lipodystrophy, and in healthy controls. Real-time reverse transcription-PCR was performed to quantitate total lipin expression levels, and expression of two lipin isoforms (lipin-alpha and -beta) that are generated by alternative mRNA splicing.

RESULTS

As predicted from studies with mice, lipin mRNA levels were correlated with limb fat mass in HIV patients, with lower lipin levels in patients with lipodystrophy than those without lipodystrophy. Unexpectedly, however, this was explained by an increase in lipin-beta expression in HIV patients without lipodystrophy compared to patients with lipodystrophy and control subjects. In addition, lipin expression levels were inversely correlated with adipose tissue expression of inflammatory cytokines interleukin (IL)-6, IL-8 and IL-18, which typically increase in HIV-associated lipoatrophy.

CONCLUSIONS

Elevated lipin expression levels are associated both with the maintenance of greater fat mass and lower cytokine expression in HIV-infected patients. Based on the demonstrated role for lipin in promoting lipogenic gene expression, these observations raise the possibility that variations in lipin levels may contribute to variations in adipose tissue mass and function that distinguish HIV patients with and without lipodystrophy.

Recombinant methionyl human leptin therapy in replacement doses improves insulin resistance and metabolic profile in patients with lipoatrophy and metabolic syndrome induced by the highly active antiretroviral therapy

CONTEXT

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

OBJECTIVE

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

DESIGN, SETTING, PATIENTS, AND INTERVENTION

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

MAIN OUTCOME MEASURES

Insulin resistance, lipid levels, inflammatory markers, body composition, and HIV control were measured.

RESULTS

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

CONCLUSIONS

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

Physiologic growth hormone replacement improves fasting lipid kinetics in patients with HIV lipodystrophy syndrome

BACKGROUND

HIV lipodystrophy syndrome (HLS) is characterized by accelerated lipolysis, inadequate fat oxidation, increased hepatic reesterification, and a high frequency of growth hormone deficiency (GHD). The effect of growth hormone (GH) replacement on these lipid kinetic abnormalities is unknown.

OBJECTIVE

We aimed to measure the effects of physiologic GH replacement on lipid kinetics in men with HLS and GHD.

DESIGN

Seven men with HLS and GHD were studied with the use of infusions of [13C1]palmitate, [2H5]glycerol, and [2H3]leucine to quantify total and net lipolysis, palmitate and free fatty acid (FFA) oxidation, and VLDL apolipoprotein B-100 synthesis before and after 6 mo of GH replacement (maximum: 5 microg x kg(-1) x d(-1)).

RESULTS

GH replacement decreased the rates of total lipolysis [FFA(total) rate of appearance (x +/- SE): from 4.80 +/- 1.24 to 3.32 +/- 0.76 mmol FFA x kg fat(-1) x h(-1); P < 0.05] and net lipolysis (FFA(net) rate of appearance: from 1.87 +/- 0.34 to 1.20 +/- 0.25 mmol FFA x kg fat(-1) x h(-1); P < 0.05). Fat oxidation decreased (from 0.28 +/- 0.02 to 0.20 +/- 0.02 mmol FFA x kg lean body mass(-1) x h(-1); P < 0.002), as did the rate of appearance of FFAs available for intrahepatic reesterification (from 0.50 +/- 0.13 to 0.29 +/- 0.09 mmol FFA x kg fat(-1) x h(-1); P < 0.03). Fractional and absolute synthetic rates of VLDL apolipoprotein B-100 were unaltered. These kinetic changes were associated with a decrease in the waist-to-hip ratio but no significant change in fasting plasma lipid concentrations. Fasting plasma glucose concentrations increased after treatment (from 5.2 +/- 0.2 to 5.8 +/- 0.3 mmol/L; P < 0.01).

CONCLUSIONS

Physiologic GH replacement has salutary effects on abnormal lipid kinetics in HLS. The effects are mediated by diminished lipolysis and hepatic reesterification rather than by increased fat oxidation.

Toxic metabolic syndrome associated with HAART

Acquired fat redistribution, that is, peripheral fat loss often accompanied by central fat accumulation in patients with HIV infection is the most common form of lipodystrophy in man. Approximately 30 - 50% of HIV-infected individuals after > or = 12 months on highly active antiretroviral therapy (HAART) may encounter the HIV-associated lipodystrophy syndrome (HALS), which attenuates patient compliance to this treatment. HALS is characterised by impaired glucose and lipid metabolism and other risk factors for cardiovascular disease. This review depicts the metabolic abnormalities associated with HAART by describing the key cell and organ systems that are involved, emphasising the role of insulin resistance. An opinion on the remedies available to treat the metabolic abnormalities and phenotype of HALS is provided.

Growth hormone secretion among HIV infected patients: effects of gender, race and fat distribution

OBJECTIVE

To determine the effects of gender, race, and fat redistribution on growth hormone (GH) secretory patterns in HIV-infected patients.

DESIGN

We investigated GH responses to growth hormone releasing hormone (GHRH) + arginine stimulation testing in HIV-infected subjects with fat redistribution, comparing HIV-infected males (n = 139) and females (n = 25) to non HIV-infected male (n = 25) and female (n = 26) control subjects similar in age, body mass index and race.

METHODS

A standard GHRH + arginine stimulation test [GHRH 1 microg/kg and arginine 0.5 g/kg (maximum dose 30 g)] was performed, and fat redistribution was assessed by anthropometry.

RESULTS

HIV-infected women had significantly higher peak GH in response to GHRH + arginine (36.4 +/- 7.3 versus 18.9 +/- 2.0 ng/ml; P = 0.003) and GH area under curve (AUC) (2679 +/- 593 versus 1284 +/- 133 (mg-min)/dl, P < 0.001) compared to HIV-infected men. Among men, a cutoff of 7.5 ng/ml for peak GH response on the GHRH + arginine test achieved good specificity and sensitivity and optimally separated the HIV and control groups (e.g., the failure rates were 37% versus 8%; P = 0.004, respectively). Among women, no specific cutoff could be determined to separate the HIV-infected and control subjects. Non-Caucasians demonstrated a higher GH AUC response compared to Caucasians, among the HIV-infected male subjects. In stepwise regression modeling waist-to-hip ratio was most significantly related to peak GH in response to GHRH + arginine in HIV-infected men.

CONCLUSIONS

HIV-infected men with fat redistribution have significantly reduced GH peak responses and increased failure rates to standardized GH stimulation testing in comparison to healthy male control subjects and to HIV-infected women of similar age and body mass index. GH secretion is related to gender and race in HIV-infected patients.