Impact of inflammatory cytokine and adipokine gene variations in the development of HIV-associated lipodystrophy

Cytokines affect lipid and glucose metabolism and also alter the body's habitus. They play a role in the development of lipodystrophy syndrome. Adipocytes secrete the pro-inflammatory cytokines IL-1, TNF-α and IL-6. The plasma cytokine concentration is associated with the percentage and distribution of fat tissue in the body. The metabolic disturbances are strongly associated with increased levels of pro-inflammatory cytokines (IL-1, IL-6 and TNF-α). Plasma levels of cytokines such as TNF-α, IL-6 and leptin were found to be increased while plasma resistin levels were found to be variable in patients suffering from obesity and type II diabetes mellitus. Until now, limited information has been available on the polymorphism of cytokine and adipokine genes in patients of HIV-associated lipodystrophy (HIVLD), which can contribute to individual variations in susceptibility to metabolic diseases, especially to HIVLD. Hence, we studied the association of cytokine and adipokine gene polymorphisms in various diseases and their impact on HIVLD. We carry out an extensive search using several databases, including PubMed, EMBASE and Google Scholar. The distribution of cytokine and adipokine gene polymorphisms and their expression levels varied among various populations. We examined the variants of cytokine and adipokine genes, which can contribute to individual variations in susceptibility to metabolic diseases, especially to HIVLD. In the current review, we present a brief account of the risk factors of HIVLD, the pathogenesis of HIVLD and the polymorphism of cytokine and adipokine genes in various diseases with special reference to their impact on HIVLD.

Exercise improves cytokine profile in HIV-infected people: A randomized clinical trial

PURPOSE

Verify the effects of concurrent training on cytokines in people living with HIV under antiretroviral therapy (ART) treatment.

METHODS

This was a blinded, parallel-group, clinical trial, where 49 participants, divided in two groups, either control group or concurrent training group, took part in the intervention. The control group performed recreational activities and concurrent training group participated of 16-week, 3 times per week of heart rate guided-aerobic plus resistance training for major muscular groups. Cytokines (interleukins 4, 5, 6, 8, 10, tumor necrosis factor-α, interferon-γ, and granulocyte-macrophage colony-stimulating factor) were measured before and after 16-week experimental period using flow cytometry.

RESULTS

From 49 participants who took part in the intervention, 28 completed the program and had data analyzed. There was a significant interaction for IL-8, which increased for control group: 7.1±5.1 vs. 8.1±6.0 and a decrease for concurrent training: 8.0±4.4 vs. 5.4±2.3. In addition, magnitude-based inference showed a likely beneficial effect for the training group when compared to the control group for IL-8, IL-5, and IL-10. The difference perceptual: mean and [CI 90%] between delta of difference within groups was -43.1 [-64.0 to -10.0] and -6.6 [-14.7 to 2.3], respectively.

CONCLUSION

Short-term exercise is able to decrease the levels of IL-5, IL-8, and IL-10 in HIV-infected people undergoing ART.

Hemeoxygenase-1 as a Novel Driver in Ritonavir-Induced Insulin Resistance in HIV-1-Infected Patients

BACKGROUND

Hemeoxygenase-1 (HO-1) has recently been identified as a major driver of metaflammation and obesity-related insulin resistance (IR). Drug-induced IR increases cardiovascular risk within the HIV-1-infected population receiving antiretroviral therapy (ART). We therefore investigated a possible role of HO-1 in ART-induced IR.

METHODS

Effects of HIV-1 protease inhibitor ritonavir and integrase inhibitor raltegravir (RAL) on expression levels of HO-1 and proinflammatory cytokines, including interleukin 1β (IL-1β), IL-6, IL-8, tumor necrosis factor-α (TNFα), chemokine (C-C motif) ligand 5 (CCL5), and monocyte chemotactic protein 1 (MCP-1), were studied in monocyte and hepatocyte cell lines. Plasma levels of HO-1 and inflammatory markers were measured in insulin-resistant and insulin-sensitive HIV-1-infected patients under ART and seronegative controls.

RESULTS

We show that, in contrast to RAL, ritonavir treatment significantly increases mRNA expression levels of HO-1, IL-8, TNFα, CCL5, and MCP-1 in vitro in a dose-dependent manner. HO-1 plasma levels were significantly higher in insulin-resistant compared to insulin-sensitive patients on ritonavir-boosted ART (lopinavir/ritonavir group: 3.90 ± 1.15 vs 2.56 ± 1.07 ng/mL, P < 0.005 and darunavir/ritonavir group: 3.16 ± 1.37 vs 2.28 ± 1.23 U/mL, P < 0.05) and were correlated with expression levels of TNFα in individuals on ritonavir-boosted ART (lopinavir/ritonavir group: r = 0.108, P < 0.05 and darunavir/ritonavir group: r = 0.221, P < 0.05) but not in HIV-1-infected individuals receiving RAL or in seronegative controls.

IMPLICATIONS

HIV-1-infected patients on stable ART are often faced with non-AIDS-related metabolic comorbidities, increasing their individual cardiovascular risk. Here, we provide insight into a novel mechanism of ritonavir-induced IR involving proinflammatory properties of HO-1. Our initial observations might also provide prognostic value in the future to identify patients at risk for the development type 2 diabetes mellitus.

A histomorphometric study on the effects of antiretroviral therapy (ART) combined with a high-calorie diet (HCD) on aortic perivascular adipose tissue (PVAT)

Perivascular adipose tissue (PVAT), surrounding arteries is metabolically active. Obesity and antiretroviral therapy (ART) may cause pathophysiological conditions in the aortic wall and surrounding PVAT. The aim of the study was to determine the histological effects on the aortic wall, aortic PVAT adipocyte morphology and leptin staining intensity in obese rats treated with ART. Wistar rats (N=36) were divided into four groups; a lean control (C/ART-), ART control (C/ART+), high-calorie diet (HCD) untreated (HCD/ART-) and HCD and ART experimental (HCD/ART+). The aorta and surrounding PVAT were stained with haematoxylin and eosin (H&E) and anti-leptin antibodies for immunohistochemistry (IHC). The C/ART+ group had a thinner tunica media compared to the HCD/ART- group. The tunica adventitia was thicker in the ART groups (C/ART+ and HCD/ART+) compared to the lean control group. White adipocytes in the HCD/ART- group was larger in size compared to the other three groups. The high-calorie diet groups (HCD/ART- and HCD/ART+) had increased adipocyte sizes, for both brown and differentiating adipocytes, compared to the control groups (C/ART- and C/ART+). The unilocular and differentiating adipocytes in the C/ART+ group showed intense leptin staining. Unilocular and differentiating adipocytes in the HCD/ART- and HCD/ART+ groups showed weak to no leptin staining intensity. The present study indicated that ART and a HCD, separately and combined, altered both the tunica media and adventitia of the aortic wall, whereas the HCD alone caused adipocytes to increase in size. The leptin staining intensity suggested that ART alone may lead to increased leptin expression, whereas ART combined with a HCD may cause leptin deficiency. Changes seen with ART in a rat model suggest that aortic wall thickness and PVAT adipocyte morphology alterations should be considered by clinicians in obese individuals receiving ART.

Dysfunctional Subcutaneous Fat With Reduced Dicer and Brown Adipose Tissue Gene Expression in HIV-Infected Patients

CONTEXT

HIV patients are at an increased risk for cardiometabolic disease secondary to depot-specific alterations in adipose function, but mechanisms remain poorly understood.

OBJECTIVE

The endoribonuclease Dicer has been linked to the modulation of brown and white adipocyte differentiation. We previously demonstrated that Dicer knockout mice undergo transformation of brown adipose tissue to white adipose tissue and develop a lipodystrophic phenotype. We hypothesized reduced Dicer and brown adipose tissue gene expression from nonlipomatous sc fat among HIV patients with a lipodystrophic phenotype.

DESIGN

Eighteen HIV (nine with and without lipodystrophic changes in fat distribution, characterized by excess dorsocervical adipose tissue [DCAT]) and nine non-HIV subjects underwent punch biopsy of abdominal sc fat to determine expression of Dicer and other adipose-related genes.

RESULTS

HIV subjects with long-duration antiretroviral use demonstrated excess DCAT vs non-HIV subjects (9.8 ± 1.0 vs 6.6 ± 0.8 cm(2), P = .02) with similar body mass index. Dicer expression was decreased in abdominal sc fat of HIV vs non-HIV (4.88 [1.91, 11.93] vs 17.69 [10.72, 47.91], P = .01), as were PPARα, ZIC1, PRDM16, DIO2, and HSP60 (all P ≤ .03). Moreover, the expression of Dicer (2.49 [0.02, 4.88] vs 11.20 [4.83, 21.45], P = .006), brown fat (PPARα [P = .002], ZIC1 [P = .004], LHX8 [P = .03], PRDM16 [P = .0008], PAT2 [P = .008], P2RX5 [P = .02]), beige fat (TMEM26 [P = .004], CD137 [P = .008]), and other genes (DIO2 [P = .002], leptin [P = .003], HSP60 [P = .0004]) was further decreased in abdominal sc fat comparing HIV subjects with vs without excess DCAT. Down-regulation of Dicer in the abdominal sc fat correlated with the down-regulation of all brown and beige fat genes (all P ≤ .01).

CONCLUSION

Our results demonstrate dysfunctional sc adipose tissue marked by reduced Dicer in relationship to the down-regulation of brown and beige fat-related genes in lipodystrophic HIV patients and may provide a novel mechanism for metabolic dysregulation. A strategy to increase browning of white adipose tissue may improve cardiometabolic health in HIV.

Telmisartan and Insulin Resistance in HIV (TAILoR): protocol for a dose-ranging phase II randomised open-labelled trial of telmisartan as a strategy for the reduction of insulin resistance in HIV-positive individuals on combination antiretroviral therapy

INTRODUCTION

Telmisartan, an angiotensin receptor blocker, has beneficial effects on insulin resistance and cardiovascular health in non-HIV populations. This trial will evaluate whether telmisartan can reduce insulin resistance in HIV-positive individuals on combination antiretroviral therapy.

METHODS AND ANALYSIS

This is a phase II, multicentre, randomised, open-labelled, dose-ranging trial of telmisartan in 336 HIV-positive individuals over a period of 48 weeks. The trial will use an adaptive design to inform the optimal dose of telmisartan. Patients will be randomised initially 1:1:1:1 to receive one of the three doses of telmisartan (20, 40 and 80 mg) or no intervention (control). An interim analysis will be performed when half of the planned maximum of 336 patients have been followed up for at least 24 weeks. The second stage of the study will depend on the results of interim analysis. The primary outcome measure is a reduction in insulin resistance (as measured by Homeostatic Model Assessment-Insulin Resistance (HOMA-IR)) in telmisartan treated arm(s) after 24 weeks of treatment in comparison with the non-intervention arm. The secondary outcome measures include changes in lipid profile; body fat redistribution (as measured by MRI); plasma and urinary levels of various biomarkers of cardiometabolic and renal health at 12, 24 and 48 weeks. Serious adverse events will be compared between different telmisartan treated dose arm(s) and the control arm.

ETHICS AND DISSEMINATION

The study, this protocol and related documents have been approved by the National Research Ethics Service Committee North West-Liverpool Central (Ref: 12/NW/0214). On successful completion, study data will be shared with academic collaborators. The findings from TAILoR will be disseminated through peer-reviewed publications, at scientific conferences, the media and through patient and public involvement.

TRIAL REGISTRATION NUMBERS

04196/0024/001-0001;

EUDRACT

2012-000935-18;

ISRCTN

51069819.

HIV/AIDS and lipodystrophy: implications for clinical management in resource-limited settings

Introduction

Lipodystrophy is a term used to describe a metabolic complication of fat loss, fat gain, or a combination of fat loss and gain, which is associated with some antiretroviral (ARV) therapies given to HIV-infected individuals. There is limited research on lipodystrophy in low- and middle-income countries, despite accounting for more than 95% of the burden of HIV/AIDS. The objective of this review was to evaluate the prevalence, pathogenesis and prognosis of HIV-related lipoatrophy, lipohypertrophy and mixed syndrome, to inform clinical management in resource-limited settings.

Methods

We conducted a structured literature search using MEDLINE electronic databases. Relevant MeSH terms were used to identify published human studies on HIV and lipoatrophy, lipohypertrophy, or mixed syndrome in low-, low-middle- and upper-middle-income countries through 31 March 2014. The search resulted in 5296 articles; after 1599 studies were excluded (958 reviews, 641 non-human), 3697 studies were extracted for further review. After excluding studies conducted in high-income settings (n=2808), and studies that did not meet inclusion criteria (n=799), 90 studies were included in this review.

Results and Discussion

Of the 90 studies included in this review, only six were from low-income countries and eight were from lower middle-income economies. These studies focused on lipodystrophy prevalence, risk factors and side effects of antiretroviral therapy (ART). In most studies, lipodystrophy developed after the first six months of therapy, particularly with the use of stavudine. Lipodystrophy is associated with increased risk of cardiometabolic complications. This is disconcerting and anticipated to increase, given the rapid scale-up of ART worldwide, the increasing number and lifespan of HIV-infected patients on long-term therapy, and the emergence of obesity and non-communicable diseases in settings with extensive HIV burden.

Conclusions

Lipodystrophy is common in resource-limited settings, and has considerable implications for risk of metabolic diseases, quality of life and adherence. Comprehensive evidence-based interventions are urgently needed to reduce the burden of HIV and lipodystrophy, and inform clinical management in resource-limited settings.

Mitochondrial Toxicity of Indinavir, Stavudine and Zidovudine Involves Multiple Cellular Targets in white and brown adipocytes

Objective

To evaluate the mechanisms of mitochondrial toxicity associated with antiretroviral treatment.

Methods

3T3–F442A white and T37i brown adipocytes were exposed to stavudine (10 μM), zidovudine (1 μM) and indinavir (10 μM), alone or in combination. Adipocyte fat content was measured with Oil Red O staining. Quantification of mRNA levels and of mitochondrial DNA content used PCR-based techniques. Mitochondrial activities were evaluated with respiration, ATP synthesis and spectrophotometric assays. Mitochondrial mass was assessed by the fluorescent probe MitoTracker Red.

Results

In both cell types, all the treatments induced a severe defect of adipogenesis (low lipid content and decreased markers of adipogenic maturation: peroxisome proliferator-activated receptor [PPAR]γ2 and aP2 but also uncoupling protein 1 in brown adipocytes) as well as altered mitochondrial function (decreased respiration rate and increased mitochondrial mass). Drug combination did not give additional toxicity. Brown adipocytes appeared more affected than white adipocytes (lower respiration rate and decreased ATP production). The mechanisms of mitochondrial toxicity differed with the drug and the cell type. Only stavudine induced severe mitochondrial DNA depletion in both cell types. With all the treatments, white adipocytes showed a decrease in the expression of mitochondrial and nuclear-DNA-encoded respiratory chain subunits (cytochrome c oxidase [CytOx]2 and CytOx4), whereas brown adipocytes maintained normal expression in accordance with their increase of the transcriptional factors of mitochondrial biogenesis nuclear respiratory factor 1 and PPARγ coactivator (PGC)1-related cofactor PRC, but not PGC1α.

Conclusion

Our results provide evidence for dissociation between mitochondrial activity, transcription and mitochondrial DNA content, highlighting the complexity of mitochondrial toxicity, which affects multiple cellular targets.

Some HIV Antiretrovirals Increase Oxidative Stress and Alter Chemokine, Cytokine or Adiponectin Production in Human Adipocytes and Macrophages

Objectives

Adipose tissue from patients with HIV-related lipodystrophy presents a state of chronic inflammation. Altered expression of cytokines/adipokines and macrophage infiltration could be involved in patients’ insulin resistance and lipoatrophy. We tested whether antiretrovirals affected adipokine release by human subcutaneous adipocytes and cytokine/chemokine production by human macrophages and examined whether reactive oxygen species (ROS) hyperproduction was related to the effect of antiretrovirals.

Methods

Differentiated human adipocytes and PMA-THP-1 macrophages were treated with protease inhibitors (PIs: indinavir, nelfinavir, amprenavir, lopinavir, ritonavir and atazanavir) or nucleoside reverse transcriptase inhibitors (NRTIs: stavudine, zidovudine and abacavir) for 24–48 h without or with diphenylene iodonium (DPI), an inhibitor of oxidative stress. Lipid content was assessed by Oil Red O staining and ROS production by nitroblue tetrazolium (NBT) reduction. Cytokine/chemokines, adiponectin and leptin release was evaluated by ELISA or multiplex assays.

Results

In human adipocytes, PIs and NRTIs (except amprenavir, atazanavir and abacavir) reduced lipid content, adiponectin and leptin release and increased in parallel ROS production and monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-6 release. The effects of PIs, but not of NRTIs, were prevented by the addition of DPI. In PMA-THP-1 macrophages, all PIs, but no NRTI, increased macrophage inflammatory protein-1α and MCP-1 release. Lopinavir, nelfinavir, zidovudine and stavudine markedly increased ROS production and release of IL-1β and tumour necrosis factor-α.

Conclusions

Some PIs altered adipokine secretion and lipid content through ROS production in human subcutaneous adipocytes. Thymidine analogues altered adipocyte functions but their effect on adipokine secretion was not reverted by ROS production inhibition. Increased chemokine/cytokine production by adipocytes and macrophages could be involved in macrophage recruitment and participate in lipoatrophy and insulin resistance.

HIV-1 Infection Alters Gene Expression in Adipose Tissue, Which Contributes to HIV-1/Haart-Associated Lipodystrophy

Background

The aetiopathogenic bases of HIV-1-/highly active antiretroviral treatment (HAART)-associated lipodystrophy (HALS) are poorly known, but this syndrome indicates that adipose tissue is highly sensitive to either HIV-1 infection, antiretroviral drugs or their combination.

Methods

To assess the relative contribution of infection and drugs, we compared the expression of marker genes corresponding to mitochondrial function, adipocyte differentiation and metabolism, and adipokines in subcutaneous adipose tissue from healthy controls, untreated HIV-1-infected patients, and HIV-1-infected patients treated with HAART with or without HALS.

Results

Subcutaneous adipose tissue from HIV-1-infected patients contained lower concentrations of the mRNA of the mitochondrial DNA-encoded cytochrome c oxidase subunit II than that of controls. These concentrations decreased further in association with HAART. The expression of nuclear genes coding for mitochondrial proteins, peroxisome proliferator-activated receptor-γ, and adipocyte-specific markers was reduced in HIV-1-infected patients, treated or not, with respect to the controls. In contrast, the mRNA concentrations of uncoupling protein-3 and preadipocyte factor-1 increased in lipodystrophic HAART-treated patients. The genes coding for adipokines were strongly affected: tumour necrosis factor-α was upregulated, whereas adiponectin and leptin were downregulated in HIV-1-infected patients, treated or not. Thus, substantial alterations of gene expression were already present when naive patients were compared with controls. Further changes were associated with HAART and with the diagnosis of HALS.

Conclusions

Disturbances in adipose tissue gene expression are already present in untreated HIV-1-infected patients, thus indicating a role of HIV-1 infection itself in eliciting adipose tissue alterations that are worsened by HAART, which ultimately leads to HALS.

Diseases of adipose tissue: genetic and acquired lipodystrophies

Human lipodystrophies represent a group of diseases characterized by altered body fat amount and/or repartition and major metabolic alterations with insulin resistance leading to diabetic complications and increased cardiovascular and hepatic risk. Genetic forms of lipodystrophies are rare. Congenital generalized lipodystrophy or Berardinelli-Seip syndrome, autosomal recessive, is characterized by a complete early lipoatrophy and severe insulin resistance and results, in most cases, from mutations either in the seipin gene of unknown function or AGPAT2 encoding an enzyme involved in triacylglycerol synthesis. The Dunnigan syndrome [FPLD2 (familial partial lipodystrophy of the Dunnigan type)] is due to mutations in LMNA encoding the lamin A/C, belonging to the complex group of laminopathies that could comprise muscular and cardiac dystrophies, neuropathies and syndromes of premature aging. Some FPLDs are linked to loss-of-function mutations in the PPAR-gamma gene (peroxisome-proliferator-activated receptor gamma; FPLD3) with severe metabolic alterations but a less severe lipodystrophy compared with FPLD2. The metabolic syndrome, acquired, represents the most common form of lipodystrophy. HIV-infected patients often present lipodystrophies, mainly related to side effects of antiretroviral drugs together with insulin resistance and metabolic alterations. Such syndromes help to understand the mechanisms involved in insulin resistance resulting from altered fat repartition and could benefit from insulin-sensitizing effects of lifestyle modifications or of specific medications.

Tumor necrosis factor alpha is associated with insulin-mediated suppression of free fatty acids and net lipid oxidation in HIV-infected patients with lipodystrophy

Tumor necrosis factor alpha (TNF-alpha) stimulates lipolysis in man. We examined whether plasma TNF-alpha is associated with the degree by which insulin suppresses markers of lipolysis, for example, plasma free fatty acid (FFA) and net lipid oxidation (LIPOX) rate in HIV-infected patients with lipodystrophy (LIPO) and those without (controls). LIPOX was estimated by indirect calorimetry during fasting and steady state of a hyperinsulinemic euglycemic clamp in 36 (18 LIPO and 18 controls) normoglycemic HIV-infected men on highly active antiretroviral therapy. In LIPO, TNF-alpha correlated with clamp FFA (r = 0.67, P < .01), clamp LIPOX (r = 0.47, P < .05), incremental FFA (r = 0.69, P < .01), and incremental LIPOX (r = 0.64, P < .01), all of which, but not the clamp LIPOX correlation (r = 0.29, P > .05), remained significant after correction for insulin sensitivity. None of these correlations were significant in controls. In all patients, TNF-alpha correlated with clamp FFA (r = 0.61, P < .001), clamp LIPOX (r = 0.43, P < .01), and incremental FFA (r = 0.43, P < .01), with the 2 former correlations remaining significant after correction for insulin sensitivity. LIPOX and FFA (fasting and clamp values combined) correlated strongly and positively in both LIPO (R2 = 0.43, P < .001) and controls (R2 = 0.60, P < .0001). Fasting FFA and LIPOX did not differ between study groups; however, the insulin-mediated suppression of FFA and LIPOX was attenuated in LIPO (P's < .05). Our data indicate that higher TNF-alpha, independently of insulin sensitivity, is associated with attenuated insulin-mediated suppression of FFA and LIPOX in HIV-LIPO, suggesting in turn that TNF-alpha stimulates lipolysis in this syndrome. Furthermore, FFA may be a major determinant of LIPOX in HIV-infected patients on highly active antiretroviral therapy.