The HIV-1/HAART associated metabolic syndrome – Novel adipokines, molecular associations and therapeutic implications

Longitudinal proteomics of leptin treatment in humans with acute and chronic energy deficiency-induced hypoleptinemia reveal novel, mainly immune-related, pleiotropic effects

BACKGROUND

Leptin is known for its metabolic, immunomodulatory and neuroendocrine properties, but the full spectrum of molecules downstream of leptin and relevant underlying mechanisms remain to be fully clarified. Our objective was to identify proteins and pathways influenced by leptin through untargeted proteomics in two clinical trials involving leptin administration in lean individuals.

METHODS

We performed untargeted liquid chromatography-tandem mass spectrometry serum proteomics across two studies a) short-term randomized controlled crossover study of lean male and female humans undergoing a 72-h fast with concurrent administration of either placebo or high-dose leptin; b) long-term (36-week) randomized controlled trial of leptin replacement therapy in human females with acquired relative energy deficiency and hypoleptinemia. We explored longitudinal proteomic changes and run adjusted mixed models followed by post-hoc tests. We further attempted to identify ontological pathways modulated during each experimental condition and/or comparison, through integrated qualitative pathway and enrichment analyses. We also explored dynamic longitudinal relationships between the circulating proteome with clinical and hormonal outcomes.

RESULTS

289 and 357 unique proteins were identified per each respective study. Short-term leptin administration during fasting markedly upregulated several proinflammatory molecules, notably C-reactive protein (CRP) and cluster of differentiation (CD) 14, and downregulated lecithin cholesterol acyltransferase and several immunoglobulin variable chains, in contrast with placebo, which produced minimal changes. Quantitative pathway enrichment further indicated an upregulation of the acute phase response and downregulation of immunoglobulin- and B cell-mediated immunity by leptin. These changes were independent of participants' biological sex. In the long term study, leptin likewise robustly and persistently upregulated proteins of the acute phase response, and downregulated immunoglobulin-mediated immunity. Leptin also significantly and differentially affected a wide array of proteins related to immune function, defense response, coagulation, and inflammation compared with placebo. These changes were more notable at the 24-week visit, coinciding with the highest measured levels of serum leptin. We further identified distinct co-regulated clusters of proteins and clinical features during leptin administration indicating robust longitudinal correlations between the regulation of immunoglobulins, immune-related molecules, serpins (including cortisol and thyroxine-binding globulins), lipid transport molecules and growth factors, in contrast with placebo, which did not produce similar associations.

CONCLUSIONS

These high-throughput longitudinal results provide unique functional insights into leptin physiology, and pave the way for affinity-based proteomic analyses measuring several thousands of molecules, that will confirm these data and may fully delineate underlying mechanisms.

Metabolic Dysfunction-Associated Steatotic Liver Disease in People Living with HIV-Limitations on Antiretroviral Therapy Selection

Chronic liver disease is one of the main causes of morbidity and mortality in people living with HIV (PLWH). The increasing life expectancy of PLWH, effective treatment for viral hepatitis, and Western dietary patterns as well as the adverse effects of antiretroviral therapy (ART) have rendered metabolic dysfunction-associated steatotic liver disease (MASLD) the most common chronic liver disease in PLWH. The risk factors for MASLD in PLWH include traditional MASLD risk factors and additional virus-specific factors, including the adverse effects of ART. The management of patients suffering from HIV and MASLD is often challenging. Apart from the conventional management of MASLD, there are also certain limitations concerning the use of ART in this patient population. In general, the appropriate combination of antiretroviral drugs should be chosen to achieve the triad of effective viral suppression, avoidance of mitochondrial dysfunction, and deterrence of worsening the patient's metabolic profile. In the current review, we discuss the epidemiology of MASLD in PLWH, the risk factors, and the disease pathogenesis, as well as the limitations in the use of ART in this patient population, while practical recommendations on how to overcome these limitations are also given.

Effects of Prolonged Administration of Tenofovir Disoproxil Fumarate-Containing Antiviral Regimen on Renal Function in Low-Risk of Kidney Injury HIV Patients

This study intended to investigate the impact of long-term tenofovir fumarate (TDF) antiviral regimen on renal function in human immunodeficiency virus (HIV)-infected patients with low-risk of kidney injury. The observational study involving 100 HIV-infected patients without underlying diseases who achieved virological suppression and immunological recovery after sustained antiviral regimen of TDF+ lamivudine+ efavirenz (TLE) for 3.19 years. Renal function, including estimated glomerular filtration rate (eGFR), blood and urine β2 microglobulin, and other parameters, was assessed every 3 months over a period of 2.5 years. The eGFR showed a slight increasement from 116.0 at month 0 to 119.7 at month 30. Blood β2 microglobulin increased from 2.02 mg/L at month 0 to 2.77 mg/L at month 30. Compared to month 0, the difference in blood β2 microglobulin was statistically significant at month 6 and months 12-30 (P < .05). The incidence of proximal renal tubular dysfunction fluctuated from 2% at month 0 to 2.5% at month 30. The urine β2 microglobulin fluctuated from 0.5 (0.3-1.1) to 0.8 (0.5-1.35) mg/L at months 18-30, which was higher than 0.41 (0.18-1.1) mg/L at month 0 (P < .05). The abnormal concentration proportion of urine β2 microglobulin fluctuated from 72.7% to 81.3% at months 18-30, which was higher than the proportion of 57.0% at month 0. The abnormal proportion of blood β2 microglobulin, urine β2 microglobulin, and proximal renal tubular dysfunction were not correlated with eGFR (r1 = 0.119, r2 = -0.008, r3 = -0.165, P > .05). Long-term TDF antiviral regimen in low-risk of kidney injury HIV-infected patients may lead to damage in the proximal renal tubules and glomeruli. Blood and urine β2 microglobulin levels may be helpful in screening for renal dysfunction.

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.

Safety and Tolerability of Antimicrobial Agents in the Older Patient

Older patients are at high risk of infections, which often present atypically and are associated with high morbidity and mortality. Antimicrobial treatment in older individuals with infectious diseases represents a clinical challenge, causing an increasing burden on worldwide healthcare systems; immunosenescence and the coexistence of multiple comorbidities determine complex polypharmacy regimens with an increase in drug-drug interactions and spread of multidrug-resistance infections. Aging-induced pharmacokinetic and pharmacodynamic changes can additionally increase the risk of inappropriate drug dosing, with underexposure that is associated with antimicrobial resistance and overexposure that may lead to adverse effects and poor adherence because of low tolerability. These issues need to be considered when starting antimicrobial prescriptions. National and international efforts have been made towards the implementation of antimicrobial stewardship (AMS) interventions to help clinicians improve the appropriateness and safety of antimicrobial prescriptions in both acute and long-term care settings. AMS programs were shown to decrease consumption of antimicrobials and to improve safety in hospitalized patients and older nursing home residents. With the abundance of antimicrobial prescriptions and the recent emergence of multidrug resistant pathogens, an in-depth review of antimicrobial prescriptions in geriatric clinical practice is needed. This review will discuss the special considerations for older individuals needing antimicrobials, including risk factors that shape risk profiles in geriatric populations as well as an evidence-based description of antimicrobial-induced adverse events in this patient population. It will highlight agents of concern for this age group and discuss interventions to mitigate the effects of inappropriate antimicrobial prescribing.

Metabolic Syndrome and Combination Antiretroviral Therapy in HIV Patients in Periurban Hospital in Ghana: A Case-Control Study

Background

There is an increasing prevalence of cardiovascular diseases (CVDs) and risk factors in HIV patients as the levels of AIDS-related mortality and morbidity decrease. Metabolic syndrome (MetS) is the accumulation of various CVD risk factors that predict the occurrence of CVDs. We investigated the prevalence of MetS and associated risk factors in HIV patients treated with combination antiretroviral therapy (cART), cART-naïve HIV patients, and non-HIV controls.

Methods

In a case-control design, 158 cART-treated HIV patients, 150 cART-naïve HIV patients, and 156 non-HIV controls were recruited from a periurban hospital in Ghana. A structured questionnaire was used to collect data on demography, lifestyle, and medication. Anthropometric indices and blood pressure were measured. Fasting blood samples were collected to measure the plasma levels of glucose, lipid profile, and CD4+ cells. The presence of MetS was defined using the joint scientific statement criteria.

Results

The prevalence of MetS was higher in cART-treated HIV patients compared with cART-naïve HIV patients and non-HIV controls (57.3% vs. 23.6% vs. 19.2% and p < 0.001, respectively). MetS was associated with cART-treated HIV patients (odds ratio (95% CI) = 7.24 (3.41-15.39) and p < 0.001), cART-naïve HIV patients (2.04 (1.01-4.15), p=0.048), and female gender (2.42 (1.39-4.23) and p=0.002). In cART-treated HIV patients, those on zidovudine (AZT)-based regimens were associated with increased likelihood (3.95 (1.49-10.43) and p < 0.006), while those on tenofovir (TDF)-based had decreased likelihood (0.32 (0.13-0.8) and p=0.015) of having MetS.

Conclusion

In our study population, there was a high prevalence of MetS in cART-treated HIV patients compared to cART-naïve HIV patients and non-HIV controls. HIV patients on AZT-based regimens had an increased likelihood of having MetS, while those on TDF-based regimens had a reduced likelihood of having MetS.

Synergic effect of metabolic syndrome and lipodystrophy on oxidative stress and inflammation process in treated HIV-patients

The aim of this study was to assess the effect of lipodystrophy (LD) associated to metabolic syndrome (MS) on oxidative stress and inflammation in a cohort of 243 HIV-infected patients with MS, all of them under three different antiretroviral regimens. We collected immunovirological, biochemical and metabolic data, as well as anthropometric measurements. In addition, cardiovascular risk was also assessed by means of Atherogenic Index of Plasma (API) and Framingham Risk Score. The MS-LD patient set was characterized by a lower initial lymphocyte CD4 count and CD4/CD8 ratio and a higher initial viral load than the group without LD. We also found worse lipidic and glycaemic profiles (with lower HDL-cholesterol and higher triglyceride and glucose levels) in the MS-LD group. BMI, systolic blood pressure and Framingham score were significantly increased compared to MS-Non LD. In addition, patients with MS and LD had significantly higher levels of carbonylated proteins, lipid peroxidation, IL-6 and IL-8, as well as a significant decrease in the levels of leptin, adiponectin and antioxidant activities of catalase, super oxide dismutase and glutathione associated enzymes. In MS-LD HIV-1 patients, a significant negative correlation was found between Framingham Risk Score and the antioxidant biomarkers, however a positive association was found between API and protein-C reactive and carbonylated proteins. Segregating by ART, the above-mentioned conditions were worse within the MS-LD group whose treatment contained protease inhibitors, such as lopinavir. In conclusion, HIV-1 infected patients treated for at least six months, especially with regimens including PIs, showed a worsening of inflammatory process and oxidative stress.

Emerging drugs for the treatment of HIV/AIDS: a review of 2019/2020 phase II and III trials

Introduction: The study of emerging drug trials to treat people living with HIV (PLWH) helps to understand any advantages and disadvantages of therapies that will be available on the market in the short-term future as well as the mechanisms underlying a better cure.Areas covered: This review analyzes phase 2 and 3 clinical trials published between 2019 and 2020 concerning six different emerging drugs. The majority of the trials focus on long acting drugs, but also on new orally administered compounds.Expert opinion: The biggest news in antiretroviral therapy (ART) is the approval of cabotegravir/rilpivirine as a complete long-acting (LA) therapeutic regimen. It paves the way for an innovation that may change the paradigms of HIV treatment in the long term, albeit it will not be obvious to implement and treatment adherence still needs to be fully evaluated. Results of phase 3 Islatravir trials are awaited. Lenacapavir may soon reach phase 3. These drugs may pave the way for 6-month ART in the next future. Fostemsavir has been recently approved. Albuvirtide, a fusion inhibitor approved in China, presents several limitations for its intravenous use only. UB-421 and VRC01 are monoclonal antibodies against HIV. This emerging technology has shown interesting results but needs further studies.

The 1G/1G+1G/2G Genotypes of MMP1 rs1799750 Are Associated with Higher Levels of MMP-1 and Are Both Associated with Lipodystrophy in People Living with HIV on Antiretroviral Therapy

In HIV-infected patients, antiretroviral therapy (ART) is associated to adipose tissue redistribution known as lipodystrophy (LD). This study aimed at verifying the association between the polymorphism of the MMP1 gene (rs1799750) (1G/2G) and the serum levels of matrix metalloproteinase 1 (MMP-1) with LD and its subtypes in people living with HIV on ART. This is a cross-secional study. LD was self-reported. The determination of the MMP1 rs1799750 gene polymorphism was performed by real-time PCR, and the serum concentrations of MMP-1 were quantified by the enzyme-linked immunosorbent assay (ELISA) method. Of 404 participants, 204 (51%) were diagnosed with LD, of whom 89 (43%) had mixed lipodystrophy (ML), 72 (35%) had lipohypertrophy (LH), and 43 (22%) had lipoatrophy (LA). There was an association between the genotypes 1G/1G+1G/2G and higher serum levels of MMP-1 (p = .025). There was no association of MMP1 (1G/2G) with LD. Other factors associated with LD were current CD4 ≤ 350 [odds ratio (OR) = 4.85, confidence interval (CI) = 1.78-47.99, p = .0033] and serum MMP-1 levels >6.81 (OR = 2.67, CI = 1.21-6.08, p = .0165). Factors associated with ML: current CD4 ≤ 350 (OR = 5.59, CI = 1.69-20.39, p = .006); with LH: number of antiretroviral regimens used: 2 (OR = 2.06, CI = 1.01-4.20, p = .0460) and 3+ (OR = 2.09, CI = 1.00-4.35, p = .0477), and current CD4 ≤ 350 (OR = 2.08, CI = 1.00-4.24, p = .0461); and with LA: current viral load >40 (OR = 2.52, CI = 1.03-5.91, p = .0372) and current use of zidovudine (OR = 2.97, CI = 1.32-6.54, p = .0074). Higher levels of MMP-1 were associated with genotypes 1G/2G+1G/1G and with LD. Other individual risk factors were independently associated with LD, and its subtypes, suggesting that the pathogenesis itself is differently manifested for each type of LD.

Synergic effect of metabolic syndrome and lipodystrophy on oxidative stress and inflammation process in treated HIV-patients

The aim of this study was to assess the effect of lipodystrophy (LD) associated to metabolic syndrome (MS) on oxidative stress and inflammation in a cohort of 243 HIV-infected patients with MS, all of them under three different antiretroviral regimens. We collected immunovirological, biochemical and metabolic data, as well as anthropometric measurements. In addition, cardiovascular risk was also assessed by means of Atherogenic Index of Plasma (API) and Framingham Risk Score. The MS-LD patient set was characterized by a lower initial lymphocyte CD4 count and CD4/CD8 ratio and a higher initial viral load than the group without LD. We also found worse lipidic and glycaemic profiles (with lower HDL-cholesterol and higher triglyceride and glucose levels) in the MS-LD group. BMI, systolic blood pressure and Framingham score were significantly increased compared to MS-Non LD. In addition, patients with MS and LD had significantly higher levels of carbonylated proteins, lipid peroxidation, IL-6 and IL-8, as well as a significant decrease in the levels of leptin, adiponectin and antioxidant activities of catalase, super oxide dismutase and glutathione associated enzymes. In MS-LD HIV-1 patients, a significant negative correlation was found between Framingham Risk Score and the antioxidant biomarkers, however a positive association was found between API and protein-C reactive and carbonylated proteins. Segregating by ART, the above-mentioned conditions were worse within the MS-LD group whose treatment contained protease inhibitors, such as lopinavir. In conclusion, HIV-1 infected patients treated for at least six months, especially with regimens including PIs, showed a worsening of inflammatory process and oxidative stress.

Adipocytokine dysregulation, abnormal glucose metabolism, and lipodystrophy in HIV-infected adolescents receiving protease inhibitors

BACKGROUND

Lipodystrophy is common in HIV-infected patients receiving protease inhibitors (PIs), stavudine, and zidovudine. Adipocytokines may be altered in lipodystrophy. We evaluated risk factors, adipocytokine levels, insulin resistance, and lipid profiles in HIV-infected adolescents with different lipodystrophy types.

METHODS

A cross-sectional study was conducted in 80 perinatally HIV-infected adolescents receiving PI-based highly active antiretroviral therapy for ≥ 6 months. Patients underwent oral glucose tolerance tests and measurements of high-molecular-weight (HMW) adiponectin, leptin, resistin, insulin, and lipids. They were classified into 3 groups based on the clinical findings: no lipodystrophy, isolated lipoatrophy, and any lipohypertrophy (isolated lipohypertrophy or combined type).

RESULTS

Of the 80 patients (median age, 16.7 years), 18 (22.5%) had isolated lipoatrophy, while 8 (10%) had any lipohypertrophy (four with isolated lipohypertrophy, and four with the combined type). In a multivariate analysis, longer exposure to stavudine (OR: 1.03; 95% CI, 1.01-1.06; p = 0.005) and indinavir (OR: 1.03; 95% CI, 1.01-1.06; p = 0.012) were associated with lipoatrophy, while longer exposure to didanosine (OR: 1.04; 95% CI, 1.01-1.08; p = 0.017) and indinavir (OR: 1.10; 95% CI, 1.00-1.21; p = 0.045) were associated with any lipohypertrophy. Leptin levels were highest in the any-lipohypertrophy group and lowest in the isolated-lipoatrophy group (p = 0.013). HMW adiponectin levels were significantly lowest in the any-lipohypertrophy group and highest in the no-lipodystrophy group (p = 0.001). There were no significant differences in the levels of resistin among the three groups (p = 0.234). The prevalence of insulin resistance (p = 0.002) and prediabetes/diabetes (p < 0.001) were significantly highest in the any-lipohypertrophy group. Patients with lipoatrophy and those without lipodystrophy had comparable degrees of insulin resistance (p = 0.292). In multiple linear regression analysis, adjusted for age, sex, and waist-height ratio, HMW adiponectin levels were associated with Matsuda index (β = 0.5; p = 0.003) and quantitative insulin sensitivity check index (QUICKI) (β = 40.1; p = 0.010) and almost significantly associated with homeostatic model assessment of insulin resistance (HOMA-IR) (p = 0.054). Leptin and resistin levels were not associated with HOMA-IR, Matsuda index, or QUICKI (all p > 0.05).

CONCLUSIONS

Abnormal glucose metabolism and dysregulation of adipocytokines were common in the HIV-infected adolescents with lipohypertrophy and the combined type. Preventive screening for cardiovascular diseases caused by metabolic alterations should be routinely performed.

The effects of omega-3 fatty acid supplementation on inflammatory factors in HIV-infected patients: A systematic review and meta-analysis of randomized clinical trials

High concentrations of C-reactive protein (CRP) and inflammatory markers are common in human immunodeficiency virus (HIV)-infected patients and are associated with non-HIV related comorbidity and mortality. Data on the benefits of omega-3 fatty acid (omega-3 FA) supplementation for improving inflammation status in HIV-infected patients are controversial. Thus, we conducted a systematic review and meta-analysis on the beneficial effects of omega-3 FAs on controlling inflammation in HIV-infected patients. We conducted a comprehensive search of the major biomedical databases, including PubMed, EMBASE, Scopus, Web of Science and Cochrane library, for all potentially relevant studies published without restriction from the beginning of time to June 2020. Overall, nine RCTs were included comprising a total of 427 participants. A random-effects model was used to calculate 95% confidence intervals (CI) and the effect was measured as standardized mean difference (SMD). Supplementation of omega-3 FAs showed a significant reduction of CRP (SMD: -0.27, 95% CI: -0.48 to -0.07, P = 0.007). There was no significant difference in levels of TNF-α (SMD: 0.03, 95% CI: -0.79 to 0.85, P = 0.94, I² = 87%) and IL-6 (SMD: -0.13, 95% CI: -0.59 to 0.32, P = 0.57, I² = 73%, Fig. 3). The results indicate that the supplementation of omega-3 FAs in HIV-infected patients significantly decreases serum CRP levels when compared to the control group, however has no significant effect on IL-6 and TNF-α levels.

HIV and antiretroviral therapy-related fat alterations

Early in the HIV epidemic, lipodystrophy, characterized by subcutaneous fat loss (lipoatrophy), with or without central fat accumulation (lipohypertrophy), was recognized as a frequent condition among people living with HIV (PLWH) receiving combination antiretroviral therapy. The subsequent identification of thymidine analogue nucleoside reverse transcriptase inhibitors as the cause of lipoatrophy led to the development of newer antiretroviral agents; however, studies have demonstrated continued abnormalities in fat and/or lipid storage in PLWH treated with newer drugs (including integrase inhibitor-based regimens), with fat gain due to restoration to health in antiretroviral therapy-naive PLWH, which is compounded by the rising rates of obesity. The mechanisms of fat alterations in PLWH are complex, multifactorial and not fully understood, although they are known to result in part from the direct effects of HIV proteins and antiretroviral agents on adipocyte health, genetic factors, increased microbial translocation, changes in the adaptive immune milieu after infection, increased tissue inflammation and accelerated fibrosis. Management includes classical lifestyle alterations with a role for pharmacological therapies and surgery in some patients. Continued fat alterations in PLWH will have an important effect on lifespan, healthspan and quality of life as patients age worldwide, highlighting the need to investigate the critical uncertainties regarding pathophysiology, risk factors and management.

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.

Diagnostic strategies and clinical management of lipodystrophy

Introduction: Lipodystrophy is a heterogeneous group of rare diseases characterized by various degrees of fat loss which leads to serious morbidity due to metabolic abnormalities associated with insulin resistance and subtype-specific clinical features associated with underlying molecular etiology.Areas covered: This article aims to help physicians address challenges in diagnosing and managing lipodystrophy. We systematically reviewed the literature on PubMed and Google Scholar databases to summarize the current knowledge in lipodystrophy management.Expert opinion: Adipose tissue is a highly active endocrine organ that regulates metabolic homeostasis in the human body through a comprehensive communication network with other organ systems such as the central nervous system, liver, digestive system, and the immune system. The adipose tissue is capable of producing and secreting numerous factors with important endocrine functions such as leptin that regulates energy homeostasis. Recent developments in the field have helped to solve some of the mysteries behind lipodystrophy that allowed us to get a better understanding of adipocyte function and differentiation. From a clinical standpoint, physicians who suspect lipodystrophy should distinguish the disease from several others that may present with similar clinical features. It is also important for physicians to carefully interpret clinical features, laboratory, and imaging results before moving to more sophisticated tests and making decisions about therapy.

Fatty liver in lipodystrophy: A review with a focus on therapeutic perspectives of adiponectin and/or leptin replacement

Lipodystrophy is a group of clinically heterogeneous, inherited or acquired, disorders characterized by complete or partial absence of subcutaneous adipose tissue that may occur simultaneously with the pathological, ectopic, accumulation of fat in other regions of the body, including the liver. Fatty liver adds significantly to hepatic and extra-hepatic morbidity in patients with lipodystrophy. Lipodystrophy is strongly associated with severe insulin resistance and related comorbidities, such as hyperglycemia, hyperlipidemia and nonalcoholic fatty liver disease (NAFLD), but other hepatic diseases may co-exist in some types of lipodystrophy, including autoimmune hepatitis in acquired lipodystrophies, or viral hepatitis in human immunodeficiency virus (HIV)-associated lipodystrophy. The aim of this review is to summarize evidence linking lipodystrophy with hepatic disease and to provide a special focus on potential therapeutic perspectives of leptin replacement therapy and adiponectin upregulation in lipodystrophy.

Lower serum adiponectin level is associated with lipodystrophy among HIV-infected men in the Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy (SUN) study

OBJECTIVES

Adiponectin levels are inversely related to cardiovascular risk and are low in diabetics and obese persons. We examined the association between adiponectin concentration and HIV-associated lipodystrophy, which remains unclear.

METHODS

The Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy (SUN) was a prospective cohort study of HIV-infected adults conducted in four US cities. Lean body and fat masses were assessed using dual-energy X-ray absorptiometry scans. Using baseline data from 2004 to 2006, we defined lipodystrophy using a sex-specific fat mass ratio and performed cross-sectional analyses of associated risks using multivariable logistic regression.

RESULTS

Among 440 male participants (median age 42 years; 68% non-Hispanic white; 88% prescribed combination antiretroviral therapy; median CD4 lymphocyte count 468 cells/μL; 76% with viral load < 400 HIV-1 RNA copies/mL; 5% diabetic; median body mass index 25 kg/m² ), median concentrations of leptin and adiponectin were 3.04 ng/L [interquartile range (IQR) 1.77-5.43 ng/L] and 8005 μg/mL (IQR 4950-11 935 μg/mL), respectively. The prevalence of lipodystrophy was 14%. Lipodystrophy was significantly associated with increasing age [prevalence ratio (PR) 1.50; 95% confidence interval (CI) 1.10-2.06, per 10 years], adiponectin < 8005 μg/mL (PR 5.02; 95% CI 2.53-9.95), ever stavudine use (PR 2.26; 95% CI 1.36-3.75), CD4 cell count > 500 cells/μL (PR 2.59; 95% CI 1.46-4.61), viral load < 400 copies/mL (PR 3.98; 95% CI 1.25-12.6), highly sensitive C-reactive protein < 1.61 mg/L (PR 1.91; 95% CI 1.11-3.28) and smoking (PR 0.42; 95% CI 0.22-0.78).

CONCLUSIONS

Among men in this HIV-infected cohort, the prevalence of lipodystrophy was similar to previous estimates for persons living with HIV, and was associated with lower adiponectin levels, potentially indicating increased cardiovascular disease risk.

An allosteric antibody to the leptin receptor reduces body weight and reverses the diabetic phenotype in the Lep(ob) /Lep(ob) mouse

OBJECTIVE

Leptin (LEP) deficiency results in major metabolic perturbations, including obesity, dyslipidemia, and diabetes. Although LEP deficiency can be treated with daily injections of a recombinant LEP, generation of an antibody activating the LEP receptor (LEPR) that has both an intrinsically long half-life and low immunogenicity could be useful in the treatment of this condition.

METHODS

Phage display technology coupled with flow cytometry and cell-based in vitro assays were employed to identify an allosteric agonist of the mouse LEPR. LEP-deficient Lep(ob) /Lep(ob) mice were used to compare in vivo effects of LEP to antibody administration. To evaluate hypothalamic effects of treatment, changes in mRNA levels of neuropeptide Y and proopiomelanocortin were measured.

RESULTS

XPA.80.037 is a monoclonal antibody that demonstrates allosteric agonism of the mouse LEPR. Treatment of Lep(ob) /Lep(ob) mice with XPA.80.037 markedly reduced hyperphagia and body weight, normalized blood glucose and plasma insulin levels, and corrected dyslipidemia. These metabolic alterations correlated with changes in mRNA levels of neuropeptide Y and proopiomelanocortin, suggesting that XPA.80.037 had hypothalamic effects.

CONCLUSIONS

Agonist allosteric monoclonal antibodies to the LEPR can correct metabolic effects associated with LEP deficiency in vivo and thereby have the potential to treat conditions of LEP deficiency.

Hypertension Is a Key Feature of the Metabolic Syndrome in Subjects Aging with HIV

With widespread and effective antiretroviral therapy, the life expectancy in the HIV population has dramatically improved over the last two decades. Consequently, as patients are aging with HIV, other age-related comorbidities, such as metabolic disturbances and cardiovascular disease (CVD), have emerged as important causes of morbidity and mortality. An overrepresentation of traditional cardiovascular risk factors (RF), toxicities associated with long exposure to antiretroviral therapy, together with residual chronic inflammation and immune activation associated with HIV infection are thought to predispose to these metabolic complications and to the excess risk of CVD observed in the HIV population. The metabolic syndrome (MS) represents a clustering of RF for CVD that includes abdominal obesity, hypertension, dyslipidemia and insulin resistance. Hypertension is a prevalent feature of the MS in HIV, in particular in the aging population, and constitutes an important RF for CVD. Physicians should screen their patients for metabolic and cardiovascular risk at the regular visits to reduce MS and the associated CVD risk among people aging with HIV, since many of RF are under-diagnosed and under-treated conditions. Interventions to reduce these RF can include lifestyle changes and pharmacological interventions such as antihypertensive and lipid-lowering therapy, and treatment of glucose metabolism disturbances. Changes in antiretroviral therapy to more metabolic neutral antiretroviral drugs may also be considered.

Effect of adiponectin-encoding gene ADIPOQ single nucleotide polymorphisms +45 and +276 on serum lipid levels after antiretroviral therapy in Japanese patients with HIV-1-infection

Objectives

To investigate the association between single nucleotide polymorphisms (SNPs) in the adiponectin-encoding gene ADIPOQ and changes in serum lipid levels in HIV-1-infected patients after antiretroviral therapy (ART).

Methods

ART-naïve HIV-1-infected patients were recruited to this prospective analysis. SNP +45 and SNP +276 genotype was determined by direct sequencing. Multivariate linear regression analysis was performed to analyse the effects of genotype, and predisposing conditions on serum total cholesterol and triglyceride in the 4 months before and after ART initiation.

Results

The study enrolled 78 patients with HIV-1-infection (73 male, five female; age range 22–67 years). HIV-1 viral load ≥5 log₁₀ copies/ml, baseline total cholesterol ≥160 mg/dl, and CD4⁺ lymphocyte count <200/µl were associated with increased serum total cholesterol levels after ART initiation. Protease inhibitor treatment and body mass index ≥25 kg/m² were associated with increased triglyceride levels after ART initiation. There were no significant associations between SNP +45 or SNP +276 genotype and serum total cholesterol or triglyceride levels.

Conclusions

SNP +45 and SNP +276 genotype is not associated with changes in serum total cholesterol or triglyceride levels after ART initiation.

Effects of a Low Dose of Fish Oil on Inflammatory Markers of Brazilian HIV-Infected Adults on Antiretroviral Therapy: A Randomized, Parallel, Placebo-Controlled Trial

Background: The benefits of antiretroviral therapy for HIV-infected subjects have been limited by an increased risk of metabolic and cardiovascular diseases. The objective of this study was to assess the effects of a low dose of marine omega-3 fatty acids on inflammatory marker concentrations in HIV-infected subjects under antiretroviral therapy (ART). Methods: This was a randomized, parallel, placebo-controlled trial that investigated the effects of 3 g fish oil/day (540 mg of eicosapentaenoic acid—EPA plus 360 mg of docosahexaenoic acid—DHA) or 3 g soy oil/day (placebo) for 24 weeks in 83 male and non-pregnant female HIV-infected adults on ART. Results: There were no differences between groups for the measures at baseline. Multilevel analyses revealed no statistically significant relationship between the longitudinal changes in high sensitivity-C reactive protein (hs-CRP) (Wald Chi2 = 0.17, p = 0.918), fibrinogen (Wald Chi2 = 3.82, p = 0.148), and factor VIII (Wald Chi2 = 5.25, p = 0.073) with fish oil. No significant changes in interleukin-6 (IL6), interleukin-1 beta (IL1-beta) and tumor necrosis factor-alpha (TNF-alpha) serum concentrations were observed with fish oil supplements for 12 weeks. Conclusions: Compared to placebo, a low dose of 900 mg omega-3 fatty acids (EPA plus DHA) in fish oil capsules did not change hs-CRP, fibrinogen, factor VIII, IL6, IL1-beta and TNF-alpha serum concentrations in HIV-infected subjects on ART. Further investigations should consider the assessment of more sensitive inflammatory markers or higher doses to evaluate the effects of marine omega-3 fatty acids in this population. Registered at the Nederlands Trial Register, Identifier no. NTR1798.

Polymorphisms in adiponectin receptor genes are associated with lipodystrophy-related phenotypes in HIV-infected patients receiving antiretroviral therapy

OBJECTIVES

Adiponectin is a circulating peptide secreted by mature adipocytes that may act as a regulator of glucose and lipid metabolism. This study aimed to investigate the association between genetic variability in the adiponectin receptor genes ADIPOR1 (adiponectin receptor 1) and ADIPOR2 and lipodystrophy and its related anthropometric and metabolic phenotypes in HIV-infected patients on highly active antiretroviral therapy (HAART).

METHODS

We studied six single nucleotide polymorphisms (SNPs) in the adiponectin receptor genes ADIPOR1 (rs1342387 and rs10920533) and ADIPOR2 (rs11061925, rs10773983, rs929434 and rs767870) and their association with adiponectin plasma levels, lipodystrophy subtypes and other parameters linked to glucose and lipid metabolism involved in the lipodystrophic syndrome. The genotypes of 407 HIV-infected patients receiving HAART were investigated using real-time polymerase chain reaction. Mean biochemical and anthropometrical parameters were compared between the different genotypes using analysis of variance.

RESULTS

Two ADIPOR2 SNPs (rs11061925 and rs929434) were associated with fasting plasma triglyceride concentrations in the entire sample. Stronger significant associations were found between these SNPs and biochemical parameters (levels of triglycerides, total cholesterol, adiponectin and glucose) in men. We did not find any significant associations with ADIPOR1 gene variants.

CONCLUSIONS

SNPs in the ADIPOR2 gene appear to be involved in the metabolic alterations in HIV-infected men receiving HAART.

Involvement of the LPS-LPB-CD14-MD2-TLR4 inflammation pathway in HIV-1/HAART-associated lipodystrophy syndrome (HALS)

OBJECTIVES

A relationship between obesity and intestinal bacterial translocation has been reported. Very little information is available with respect to the involvement of the bacterial translocation mechanistic pathway in HIV-1/highly active antiretroviral therapy (HAART)-associated lipodystrophy syndrome (HALS). We determined whether lipopolysaccharide (LPS)-binding protein (LBP), cluster of differentiation 14 (CD14), myeloid differentiation protein 2 (MD2) and toll-like receptor 4 (TLR4) single-nucleotide polymorphisms and LPS, LBP and soluble CD14 (sCD14) plasma levels are involved in HALS.

PATIENTS AND METHODS

This cross-sectional multicentre study involved 558 treated HIV-1-infected patients, 240 with overt HALS and 318 without HALS. Anthropometric, clinical, immunovirological and metabolic variables were determined. Polymorphisms were assessed by genotyping. Plasma levels were determined by ELISA in 163 patients (81 with HALS and 82 without HALS) whose stored plasma samples were available. Student's t-test, one-way ANOVA, two-way repeated measures ANOVA, the χ(2) test and Pearson and Spearman correlation analyses were carried out for statistical analysis.

RESULTS

LBP rs2232582 T→C polymorphism was significantly associated with HALS (P = 0.01 and P = 0.048 for genotype and allele analyses, respectively). Plasma levels of LPS (P = 0.009) and LBP (P < 0.001) were significantly higher and sCD14 significantly lower (P < 0.001) in patients with HALS compared with subjects without HALS. LPS levels were independently predicted by triglycerides (P < 0.001) and hepatitis C virus (P = 0.038), LBP levels by HALS (P < 0.001) and sCD14 levels by age (P = 0.008), current HIV-1 viral load (P = 0.001) and protease inhibitor use (P = 0.018).

CONCLUSIONS

HALS is associated with LBP polymorphism and with higher bacterial translocation.

Assessment of serum IGF-1 and adipokines related to metabolic dysfunction in HIV-infected adults

PURPOSE

HIV/HAART associated metabolic syndrome (HAMS) seems to result from direct influence of HIV, adverse effects of combined antiretroviral therapy (cART) and individual genetic predisposition. This study aimed to assess the influence of HIV infection and cART on serum concentration of insulin-like growth factor-1 (IGF-1) and adipokines related to metabolic abnormalities.

METHODS

Seventy-two HIV infected patients including 48 HIV/HCV coinfected were enrolled in this study. Insulin resistance was evaluated by Homeostatic Model Assessment (HOMA) indexes. Serum concentrations of IGF-1, adiponectin, chemerin and visfatin were measured by ELISA.

RESULTS

Significant correlation between serum IGF-1 level and CD4 lymphocytes count was demonstrated and the lowest values were observed in subjects with CD4<200 cells/μL. Serum concentration of IGF-1 was significantly higher in patients treated with protease inhibitors based regimen compared to non-nucleoside reverse transcriptase inhibitors and healthy subjects. A significant negative correlation between serum concentration of adiponectin and waist-hip ratio as an indicator of central obesity, was found. There were significant positive correlations between serum concentration of chemerin and HOMA1-IR and serum IGF-1 concentration. Serum chemerin was increased in patients with insulin resistance vs. those with preserved insulin sensitivity.

CONCLUSIONS

According to these results HAMS is associated with insulin resistance and imbalance of adipokines serum concentration, therefore identification of pathways related to HAMS development might be helpful in management of the syndrome. Serum IGF-1 largely depends on level of immunodeficiency in HIV-infection and may provide a link between immune dysfunction and development of HIV-associated lipodystrophy, AIDS wasting syndrome, diabetes and/or cardiovascular diseases in HIV-infected patients.

HIV-1 Nef in macrophage-mediated disease pathogenesis

Combined anti-retroviral therapy (cART) has significantly reduced the number of AIDS-associated illnesses and changed the course of HIV-1 disease in developed countries. Despite the ability of cART to maintain high CD4+ T-cell counts, a number of macrophage-mediated diseases can still occur in HIV-infected subjects. These diseases include lymphoma, metabolic diseases, and HIV-associated neurological disorders. Within macrophages, the HIV-1 regulatory protein "Nef" can modulate surface receptors, interact with signaling pathways, and promote specific environments that contribute to each of these pathologies. Moreover, genetic variation in Nef may also guide the macrophage response. Herein, we review findings relating to the Nef-macrophage interaction and how this relationship contributes to disease pathogenesis.

Maraviroc reduces cytokine expression and secretion in human adipose cells without altering adipogenic differentiation

Maraviroc (MVC) is a drug approved for use as part of HAART in treatment-experienced HIV-1 patients with CCR5-tropic virus. Despite the current concerns on the alterations in adipose tissue that frequently appear in HIV-infected patients under HAART, there is no information available on the effects of MVC on adipose tissue. Here we studied the effects of MVC during and after the differentiation of human adipocytes in culture, and compared the results with the effects of efavirenz (EFV). We measured the acquisition of adipocyte morphology; the gene expression levels of markers for mitochondrial toxicity, adipogenesis and inflammation; and the release of adipokines and cytokines to the medium. Additionally, we determined the effects of MVC on lipopolysaccharide (LPS)-induced pro-inflammatory cytokine expression in adipocytes. Unlike EFV-treated pre-adipocytes, MVC-treated pre-adipocytes showed no alterations in the capacity to differentiate into adipocytes and accumulated lipids normally. Consistent with this, there were no changes in the mRNA levels of PPARγ or SREBP-1c, two master regulators of adipogenesis. In addition, MVC caused a significant decrease in the gene expression and release of pro-inflammatory cytokines, whereas EFV had the opposite effect. Moreover, MVC lowered inflammation-related gene expression and inhibited the LPS-induced expression of pro-inflammatory genes in differentiated adipocytes. We conclude that MVC does not alter adipocyte differentiation but rather shows anti-inflammatory properties by inhibiting the expression and secretion of pro-inflammatory cytokines. Collectively, our results suggest that MVC may minimize adverse effects on adipose tissue development, metabolism, and inflammation, and thus could be a potentially beneficial component of antiretroviral therapy.

Metabolic effects of darunavir/ritonavir versus atazanavir/ritonavir in treatment-naive, HIV type 1-infected subjects over 48 weeks

We assessed metabolic changes for darunavir/ritonavir (DRV/r) once daily (qd) versus atazanavir/ritonavir (ATV/r) qd with fixed-dose tenofovir/emtricitabine. This was a phase 4, multicenter, open-label, randomized exploratory study. Treatment-naive, HIV-1-infected adults received DRV/r 800/100 mg qd or ATV/r 300/100 mg qd, both with emtricitabine/tenofovir 200/300 mg qd. Primary end point: change in triglyceride levels from baseline to week 12. Secondary end points: week 12 and week 48 changes in lipid parameters, insulin sensitivity, inflammatory/coagulation/bacterial translocation biomarkers, viral load, CD4(+) cell count, and week 48 changes in adipose tissue distribution and subjects' perceptions of body changes. In the DRV/r arm, 32/34 and 29/34 subjects completed weeks 12 and 48, respectively; in the ATV/r arm, 30/31 and 25/31 subjects completed weeks 12 and 48, respectively. Small changes in lipid parameters from baseline to weeks 12 and 48 were observed in both arms. Differences were noted between arms in mean changes in total cholesterol (DRV/r, 20.3 mg/dl; ATV/r, 4.6 mg/dl) and apolipoprotein A1 (DRV/r, 10.7 mg/dl; ATV/r, -0.7 mg/dl) at week 12. At week 48, no clinically relevant differences between arms were noted for changes in any lipid parameter, fasting glucose, or insulin sensitivity. Biomarkers generally decreased and efficacy parameters improved in both arms over 48 weeks. Changes in adipose tissue were small and comparable between arms. Subjects' perceptions of body changes generally improved in both study arms. This first pilot comparison in HIV-1-infected subjects suggests that DRV/r has a metabolic profile similar to ATV/r over 48 weeks of treatment. Further randomized studies are warranted.

Asthma diagnosis and airway bronchodilator response in HIV-infected patients

BACKGROUND

Despite the high prevalence of respiratory symptoms and obstructive lung disease in HIV-infected subjects, the prevalence of bronchodilator reversibility (BDR) and asthma has not been systematically studied during the era of combination antiretroviral therapy (ART).

OBJECTIVE

We sought to determine the prevalence of asthma diagnosis and related pulmonary function abnormalities in an HIV-infected cohort and to identify potential mechanisms.

METHODS

We performed a cross-sectional analysis of 223 HIV-infected subjects with data on respiratory symptoms and diagnoses, pulmonary function, sputum cell counts, and asthma-related cytokines and chemokines in serum/sputum.

RESULTS

Doctor-diagnosed asthma was present in 46 (20.6%), and BDR (≥200 mL and ≥12% increase in FEV(1) or forced vital capacity) was present in 20 (9.0%) participants. Pulmonary symptoms and function were worse in those with doctor-diagnosed asthma. Doctor-diagnosed asthma was independently associated with female sex (P = .04), body mass index of greater than 29.6 kg/m(2) (vs <29.6 kg/m(2), P = .03), history of bacterial or Pneumocystis pneumonia (P = .01), and not currently taking ART (P = .04) and in univariate analysis with parental history of asthma (n = 180, P = .004). High sputum eosinophil percentages (>2.3% based on the highest decile) were more likely in those with doctor-diagnosed asthma (P = .02) or BDR (P = .02). Doctor-diagnosed asthma tended to be more common with high sputum IL-4 (P = .02) and RANTES (P = .02) levels, whereas BDR was associated with high plasma macrophage inflammatory protein 1α (P = .002) and sputum macrophage inflammatory protein 1β (P = .001) levels.

CONCLUSION

Asthma diagnosis and BDR are prevalent in an HIV-infected outpatient cohort, and associations with family history, obesity, allergic inflammation, prior infection, absence of ART, and increased HIV-stimulated cytokines suggest possible mechanisms of HIV-associated asthma.

Dysregulation of glucose metabolism in HIV patients: epidemiology, mechanisms, and management

HIV-infected patients on highly active antiretroviral therapy (HAART) have increased prevalence of a number of chronic metabolic disorders of multifactorial but unclear etiology. These include disorders of lipid metabolism with or without lipodystrophy, insulin resistance, and an increased prevalence of impaired glucose tolerance, diabetes mellitus, and cardiometabolic syndrome. While much attention has been focused on the lipid and cardiovascular disorders, few investigations have attempted to characterize the prevalence, incidence, etiology, mechanisms, and management of glycemic disorders in HIV patients. In this review, we have focused specifically on a comprehensive assessment of dysglycemia in the context of HIV infection and HAART.

Zinc alpha-2 glycoprotein is implicated in dyslipidaemia in HIV-1-infected patients treated with antiretroviral drugs

OBJECTIVES

Treated HIV-1-infected patients with lipodystrophy often develop insulin resistance and proatherogenic dyslipidaemia. Zinc alpha-2 glycoprotein (ZAG) is a recently characterized adipokine which has been shown to be involved in the development of obesity and metabolic syndrome in uninfected subjects. We assessed the relationship between circulating ZAG levels and metabolic derangements in HIV-1-infected patients receiving antiretroviral drugs.

METHODS

Plasma ZAG levels were assessed in 222 individuals: 166 HIV-1-infected patients treated with antiretroviral drugs (77 with lipodystrophy and 89 without lipodystrophy) and 56 uninfected controls. Plasma ZAG levels were assessed by enzyme-linked immunosorbent assay (ELISA) and were correlated with fat distribution abnormalities and metabolic parameters.

RESULTS

HIV-1-infected patients had lower plasma ZAG levels compared with uninfected controls (P < 0.001). No differences were found in ZAG plasma levels according to the presence of lipodystrophy, components of the metabolic syndrome or type of antiretroviral treatment regimen. Circulating ZAG levels were strongly determined by high-density lipoprotein cholesterol (HDLc) in men (B = 0.644; P < 0.001) and showed a positive correlation with total cholesterol (r = 0.312; P < 0.001) and HDLc (r = 0.216; P = 0.005).

CONCLUSIONS

HIV-1-infected patients have lower plasma ZAG levels than uninfected controls. In infected patients, plasma ZAG levels are in close relationship with total cholesterol and HDLc.

The pathophysiology of HIV-/HAART-related metabolic syndrome leading to cardiovascular disorders: the emerging role of adipokines

Individuals infected with human immunodeficiency virus (HIV) frequently demonstrate metabolic syndrome (MS) associated with increased incidence of cardiovascular disorders. Characteristics of HIV infection, such as immunodeficiency, viral load, and duration of the disease, in addition to the highly active antiretroviral therapy (HAART) have been suggested to induce MS in these patients. It is well documented that MS involves a number of traditional cardiovascular risk factors, like glucose, lipids, and arterial blood pressure abnormalities, leading to extensive atherogenic arterial wall changes. Nevertheless, the above traditional cardiovascular risk factors merely explain the exacerbated cardiovascular risk in MS. Nowadays, the adipose-tissue derivatives, known as adipokines, have been suggested to contribute to chronic inflammation and the MS-related cardiovascular disease. In view of a novel understanding on how adipokines affect the pathogenesis of HIV/HAART-related MS and cardiovascular complications, this paper focuses on the interaction of the metabolic pathways and the potential cardiovascular consequences. Based on the current literature, we suggest adipokines to have a role in the pathogenesis of the HIV/HAART-related MS. It is crucial to understand the pathophysiology of the HIV/HAART-related MS and apply therapeutic strategies in order to reduce cardiovascular risk in HIV patients.

Leptin in human physiology and pathophysiology

Leptin, discovered through positional cloning 15 years ago, is an adipocyte-secreted hormone with pleiotropic effects in the physiology and pathophysiology of energy homeostasis, endocrinology, and metabolism. Studies in vitro and in animal models highlight the potential for leptin to regulate a number of physiological functions. Available evidence from human studies indicates that leptin has a mainly permissive role, with leptin administration being effective in states of leptin deficiency, less effective in states of leptin adequacy, and largely ineffective in states of leptin excess. Results from interventional studies in humans demonstrate that leptin administration in subjects with congenital complete leptin deficiency or subjects with partial leptin deficiency (subjects with lipoatrophy, congenital or related to HIV infection, and women with hypothalamic amenorrhea) reverses the energy homeostasis and neuroendocrine and metabolic abnormalities associated with these conditions. More specifically, in women with hypothalamic amenorrhea, leptin helps restore abnormalities in hypothalamic-pituitary-peripheral axes including the gonadal, thyroid, growth hormone, and to a lesser extent adrenal axes. Furthermore, leptin results in resumption of menses in the majority of these subjects and, in the long term, may increase bone mineral content and density, especially at the lumbar spine. In patients with congenital or HIV-related lipoatrophy, leptin treatment is also associated with improvements in insulin sensitivity and lipid profile, concomitant with reduced visceral and ectopic fat deposition. In contrast, leptin's effects are largely absent in the obese hyperleptinemic state, probably due to leptin resistance or tolerance. Hence, another emerging area of research pertains to the discovery and/or usefulness of leptin sensitizers. Results from ongoing studies are expected to further increase our understanding of the role of leptin and the potential clinical applications of leptin or its analogs in human therapeutics.

A polymorphism in the leptin gene promoter is associated with anemia in patients with HIV disease

To study factors associated with anemia and its effect on survival in HIV-infected persons treated with modern combined antiretroviral therapy (cART), we characterized the prevalence of anemia in the Veterans Aging Cohort Study (VACS) and used a candidate gene approach to identify proinflammatory gene single nucleotide polymorphisms (SNPs) associated with anemia in HIV disease. The study comprised 1597 HIV(+) and 865 HIV(-) VACS subjects with DNA, blood, and annotated clinical data available for analysis. Anemia was defined according to World Health Organization criteria (hemoglobin < 13 g/dL and < 12 g/dL in men and women, respectively). The prevalence of anemia in HIV(+) and HIV(-) subjects was 23.1% and 12.9%, respectively. Independent of HIV status, anemia was present in 23.4% and 8% in blacks and whites, respectively. Analysis of our candidate genes revealed that the leptin -2548 G/A SNP was associated with anemia in HIV(+), but not HIV(-), patients, with the AA and AG genotypes significantly predicting anemia (P < .003 and P < .039, respectively, logistic regression). This association was replicated in an independent cohort of HIV(+) women. Our study provides novel insight into the association between genetic variability in the leptin gene and anemia in HIV(+) individuals.

Hypertriglyceridemia, Metabolic Syndrome, and Cardiovascular Disease in HIV-Infected Patients: Effects of Antiretroviral Therapy and Adipose Tissue Distribution

The use of combination antiretroviral therapy (CART) in HIV-infected patients has resulted in a dramatic decline in AIDS-related mortality. However, mortality due to non-AIDS conditions, particularly cardiovascular disease (CVD) seems to increase in this population. CART has been associated with several metabolic risk factors, including insulin resistance, low HDL-cholesterol, hypertriglyceridemia and postprandial hyperlipidemia. In addition, HIV itself, as well as specific antiretroviral agents, may further increase cardiovascular risk by interfering with endothelial function. As the HIV population is aging, CVD may become an increasingly growing health problem in the future. Therefore, early diagnosis and treatment of cardiovascular risk factors is warranted in this population. This paper reviews the contribution of both, HIV infection and CART, to insulin resistance, postprandial hyperlipidemia and cardiovascular risk in HIV-infected patients. Strategies to reduce cardiovascular risk are also discussed.

Molecular mechanisms for insulin resistance in treated HIV-infection

Identification and characterization of the molecular mechanisms contributing to the high incidence of insulin resistance in HIV infected patients treated with combined antiretroviral therapy remains a critically important goal in the quest to improve the safety of antiretroviral treatment regimens. The use of in vitro model systems together with the investigation of drug-mediated effects on glucose homeostasis in animals and healthy human volunteers has provided important insight into the contribution of individual drugs to insulin resistance and affected cellular pathways. HIV protease inhibitor mediated blockade of glucose transport and nucleoside reverse transcriptase inhibitor mediated mitochondrial toxicity have been well characterized. Together with growing understanding of mediators of insulin resistance in non-HIV metabolic syndrome, additional cellular effects including the induction of endoplasmic reticulum and oxidative stress, altered adipocytokine secretion, and lipotoxicity have been integrated into this developing picture. Further elucidation of these mechanisms provides potential for the continued development of safer antiviral drugs and targeted treatment of insulin resistance in affected patients.