Association of upper trunk and visceral adipose tissue volume with insulin resistance in control and HIV-infected subjects in the FRAM study

Association of interarm blood pressure difference with selected body circumferences among Walter Sisulu University community

BACKGROUND

A high interarm blood pressure difference (IAD) has been identified as a precursor of vascular diseases. Anthropometric measures for obesity such as body circumferences including waist circumference (WC), mid-upper arm circumference (MUAC) and neck circumference (NC) have been associated with a high IAD in Western countries. However, the prevalence of IAD and its association with body circumferences in South African communities such as universities is not well established. Therefore, this study aimed at investigating the correlation of IAD with selected body circumferences among the Walter Sisulu University (WSU) community.

METHODS

A total of 230 participants, 117 males and 113 females, consisting of 185 students and 45 staff members from WSU, aged 18-27 and 18-63 years respectively, participated in this cross-sectional study. The selected body circumferences: WC, MUAC, and NC were measured using standard procedures. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in both arms simultaneously using automated machines. IAD was achieved by calculating differences in SBP and DBP between the left (L) and right (R) arms, (R -L), and getting the absolute value, L-R (|L-R|).

RESULTS

14.78% of the participants had an interarm SBP difference (IASBPD) ≥ 10 mmHg, and 4.35% of participants had an interarm DBP difference (IADBPD) ≥ 10 mmHg. In a Pearson's correlation analysis, IASBPD was positively correlated with the selected body circumferences (WC, r = 0.29; P < 0.001; MUAC, r = 0.35; P < 0.001; NC, r = 0.27; P < 0.001) and mean arterial pressure (MAP) (r = 0.30; P < 0.001). In the multivariable-adjusted regression analyses, IASBPD was positively associated with MUAC (adjusted R2 = 0.128, β = 0.271 (95% CI = 0.09; 0.60), P = 0.008), and NC (adjusted R2 = 0.119, β = 0.190 (95% CI = 0.01; 0.32), P = 0.032) only, adjusted for MAP, age, gender, body mass index, smoking, and alcohol. There was no association of body circumferences with IADBPD.

CONCLUSION

A high IAD is common among students and staff members of the WSU community. Furthermore, IAD showed a positive correlation with MUAC and NC. These body circumferences can serve as indicators of high IAD, aiding in the early detection and prevention of vascular diseases.

Relationships of neck circumference and abdominal obesity with insulin resistance considering relative handgrip strength in middle-aged and older individuals

PURPOSE

This cross-sectional study evaluated how neck circumference (NC) influences the association between abdominal obesity (AO) and insulin resistance (IR) while considering relative handgrip strength (RHGS) in middle-aged and older people.

METHODS

Using data from the 2019 Korea National Health and Nutrition Examination Survey for 3804 Korean adults aged 40-80 years, AO (waist circumference [WC] ≥90 cm for men, ≥85 cm for women), large NC (sex-specific highest 5th quintile), weak RHGS (sex-specific 1st quintile of HGS/body mass index), and IR (homeostasis model assessment of IR [HOMA-IR] ≥2.5) were defined. A complex sample general linear model and logistic regression analyses were performed after adjusting for confounding factors.

RESULTS

As NC increased, the relationship between WC and HOMA-IR increased (p for interaction <0.001). In the group with AO, large NC, or both, the adjusted odds ratio (AOR) for IR increased in the group with weak RHGS than in the group with normal RHGS. In the group with normal NC, the AOR for IR in those with AO (vs. those without AO) was 3.3 (95% confidence interval, 2.6-4.3) even after controlling for RHGS; however, the AOR was 5.3 (95% confidence interval, 2.7-10.4) in the group with large NC. These relationships of WC, NC, and RHGS with IR were comparable across sex and age groups.

CONCLUSIONS

Large NC increased the association between AO and IR independent of RHGS and the relationships between large NC and AO and insulin resistance varied according to RHGS.

BODY COMPOSITION CHANGES IN MEN WITH HIV/HCV COINFECTION, HIV MONOINFECTION, AND HCV MONOINFECTION

Context

Both human immunodeficiency virus (HIV) infection and hepatitis C virus (HCV) infection represent systemic diseases that may develop metabolic complications, thus HIV/HCV coinfection metabolic changes need to be depicted.

Objective

We aimed to evaluate the body composition changes in patients with either HIV and HCV monoinfections or HIV/HCV coinfection.

Methods

123 young men divided into three groups: 41 with HIV/HCV coinfection, 42 with HIV-monoinfection, and 40 with HCV-monoinfection were evaluated for total and regional bone and soft tissue body composition assessments using a Dual-energy X-ray absorptiometry (DXA) and were compared with 40 healthy men with age and body mass index similar to the study groups. To detect sarcopenia, we calculated the appendicular limbs' lean mass index (ALMI), for obesity, we used the percent of body fat, and for lipodystrophy, we calculated the trunk/limbs index.

Results

HIV/HCV coinfection is associated with a significant higher bone demineralization in all regions of interest compared to HCV or HIV monoinfections and to controls. The prevalence of bone demineralization in HIV/HCV patients was 31.7%, more frequently at lumbar spine. Fat mass and lean mass were significantly lower in HIV/HCV-coinfected patients than in controls. Lipodystrophy was found in similar percentages in all three evaluated groups (80.4% in HIV/HCV, 92.5% in HIV, and 95% in the HCV group). Sarcopenia was higher in HIV/HCV group (43.9%) and important in HCV-monoinfection group (30%).

Conclusions

HIV/HCV-coinfected patients had the highest prevalence of bone demineralization, fat mass, and lean mass loss, compared to controls and to HIV and HCV monoinfections.

Unpacking determinants and consequences of food insecurity for insulin resistance among people living with HIV: Conceptual framework and protocol for the NOURISH-OK study

Background

Over the past four decades, advances in HIV treatment have contributed to a longer life expectancy for people living with HIV (PLWH). With these gains, the prevention and management of chronic co-morbidities, such as diabetes, are now central medical care goals for this population. In the United States, food insecurity disproportionately impacts PLWH and may play a role in the development of insulin resistance through direct and indirect pathways. The Nutrition to Optimize, Understand, and Restore Insulin Sensitivity in HIV for Oklahoma (NOURISH-OK) will use a novel, multi-level, integrated framework to explore how food insecurity contributes to insulin resistance among PLWH. Specifically, it will explore how food insecurity may operate as an intermediary risk factor for insulin resistance, including potential linkages between upstream determinants of health and downstream consequences of poor diet, other behavioral risk factors, and chronic inflammation.

Methods/design

This paper summarizes the protocol for the first aim of the NOURISH-OK study, which involves purposeful cross-sectional sampling of PLWH (n=500) across four levels of food insecurity to test our conceptual framework. Developed in collaboration with community stakeholders, this initial phase involves the collection of anthropometrics, fasting blood samples, non-blood biomarkers, 24-hour food recall to estimate the Dietary Inflammatory Index (DII®) score, and survey data. A 1-month, prospective observational sub-study (total n=100; n=25 for each food security group) involves weekly 24-hour food recalls and stool samples to identify temporal associations between food insecurity, diet, and gut microbiome composition. Using structural equation modeling, we will explore how upstream risk factors, including early life events, current discrimination, and community food access, may influence food insecurity and its potential downstream impacts, including diet, other lifestyle risk behaviors, and chronic inflammation, with insulin resistance as the ultimate outcome variable. Findings from these analyses of observational data will inform the subsequent study aims, which involve qualitative exploration of significant pathways, followed by development and testing of a low-DII® food as medicine intervention to reverse insulin resistance among PLWH (ClinicalTrials.gov Identifier: NCT05208671).

Discussion

The NOURISH-OK study will address important research gaps to inform the development of food as medicine interventions to support healthy aging for PLWH.

Genetic and cytometric analyses of subcutaneous adipose tissue in patients with hemophilia and HIV-associated lipodystrophy

Background

The authors recently performed plastic surgeries for a small number of patients with hemophilia, HIV infection, and morphologic evidence of lipodystrophy. Because the pathophysiological mechanism of HIV-associated lipodystrophy remains to be elucidated, we analyzed subcutaneous adipose tissues from the patients.

Methods

All six patients had previously been treated with older nucleoside analogue reverse-transcriptase inhibitors (NRTIs; stavudine, didanosine or zidovudine). Abdominal and inguinal subcutaneous fat samples were obtained from the HIV+ patients with hemophilia and HIV− healthy volunteers (n = 6 per group), and analyzed via DNA microarray, real-time PCR, flow cytometry and immunohistochemistry.

Results

The time from initial NRTI treatment to collecting samples were 21.7 years in average. Cytometric analysis revealed infiltration of inflammatory M1 macrophages into HIV-infected adipose tissue and depletion of adipose-derived stem cells, possibly due to exhaustion following sustained adipocyte death. Genetic analysis revealed that adipose tissue from HIV+ group had increased immune activation, mitochondrial toxicity, chronic inflammation, progressive fibrosis and adipocyte dysfunction (e.g. insulin resistance, inhibited adipocyte differentiation and accelerated apoptosis). Of note, both triglyceride synthesis and lipolysis were inhibited in adipose tissue from patients with HIV.

Conclusions

Our findings provide important insights into the pathogenesis of HIV-associated lipodystrophy, suggesting that fat redistribution may critically depend on adipocytes’ sensitivity to drug-induced mitochondrial toxicity, which may lead either to atrophy or metabolic complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12981-022-00432-9.

Are Physical Fitness and CRP Related to Framingham Risk Score in HIV+ Adults?

Background. People living with HIV (PLWH) have increased risk of cardiovascular disease (CVD). The Framingham Risk Score (FRS) predicts a 10-year CVD risk. Its relationships to physical fitness and C-reactive protein (CRP) are not well established. The current aim is to determine the links between FRS, physical fitness, and CRP in PLWH. Methods. Participants (n = 87) were assessed on multiple biomarkers. The FRS was calculated with the respective variables. Other variables that correlated significantly with FRS were entered into a regression equation to determine their relationship to FRS. Results. The FRS for men was more than twice that for women (12.8 vs 6.0, P < .001). Men were more fit than women, but most participants were not fit. Aerobic capacity was predictive of FRS in men, but not in women, and muscular strength was not predictive of FRS. Women had more than double the CRP compared with men (7.9 vs 3.5 mg/L, P < .01), and it was unrelated to FRS. Conclusions. In men, aerobic capacity was significantly predictive of FRS, but muscular strength and CRP were unrelated to FRS in both genders. These results do not conclusively demonstrate that physical fitness and CRP are related to FRS in PLWH.

Chronic binge alcohol and ovariectomy dysregulate omental adipose tissue metaboproteome in simian immunodeficiency virus-infected female macaques

Effective antiretroviral therapy (ART) has significantly reduced mortality of people living with HIV (PLWH), and the prevalence of at-risk alcohol use is higher among PLWH. Increased survival and aging of PLWH is associated with increased prevalence of metabolic comorbidities especially among menopausal women, and adipose tissue metabolic dysregulation may be a significant contributing factor. We examined the differential effects of chronic binge alcohol (CBA) administration and ovariectomy (OVX) on the omental adipose tissue (OmAT) proteome in a subset of simian immunodeficiency virus (SIV)-infected macaques of a longitudinal parent study. Quantitative discovery-based proteomics identified 1,429 differentially expressed proteins. Ingenuity Pathway Analysis (IPA) was used to calculate z-scores, or activation predictions, for functional pathways and diseases. Results revealed that protein changes associated with functional pathways centered around the "OmAT metaboproteome profile." Based on z-scores, CBA did not affect functional pathways of metabolic disease but dysregulated proteins involved in adenosine monophosphate-activated protein kinase (AMPK) signaling and lipid metabolism. OVX-mediated proteome changes were predicted to promote pathways involved in glucose- and lipid-associated metabolic disease. Proteins involved in apoptosis, necrosis, and reactive oxygen species (ROS) pathways were also predicted to be activated by OVX and these were predicted to be inhibited by CBA. These results provide evidence for the role of ovarian hormone loss in mediating OmAT metaboproteome dysregulation in SIV and suggest that CBA modifies OVX-associated changes. In the context of OVX, CBA administration produced larger metabolic and cellular effects, which we speculate may reflect a protective role of estrogen against CBA-mediated adipose tissue injury in female SIV-infected macaques.

Anthropometric Indicators as a Tool for Diagnosis of Obesity and Other Health Risk Factors: A Literature Review

Obesity is characterized by the accumulation of an excessive amount of fat mass (FM) in the adipose tissue, subcutaneous, or inside certain organs. The risk does not lie so much in the amount of fat accumulated as in its distribution. Abdominal obesity (central or visceral) is an important risk factor for cardiovascular diseases, diabetes, and cancer, having an important role in the so-called metabolic syndrome. Therefore, it is necessary to prevent, detect, and appropriately treat obesity. The diagnosis is based on anthropometric indices that have been associated with adiposity and its distribution. Indices themselves, or a combination of some of them, conform to a big picture with different values to establish risk. Anthropometric indices can be used for risk identification, intervention, or impact evaluation on nutritional status or health; therefore, they will be called anthropometric health indicators (AHIs). We have found 17 AHIs that can be obtained or estimated from 3D human shapes, being a noninvasive alternative compared to X-ray-based systems, and more accessible than high-cost equipment. A literature review has been conducted to analyze the following information for each indicator: definition; main calculation or obtaining methods used; health aspects associated with the indicator (among others, obesity, metabolic syndrome, or diabetes); criteria to classify the population by means of percentiles or cutoff points, and based on variables such as sex, age, ethnicity, or geographic area, and limitations.

Mitochondria and ageing with HIV

PURPOSE OF REVIEW

Some older people living with HIV (PLWH) exhibit features of unsuccessful ageing, such as frailty. Mitochondrial dysfunction is one of the best characterized ageing mechanisms. There has been recent interest in whether some people ageing with HIV may have an excess of mitochondrial dysfunction. This review aims to address this question through: analogy with ageing and chronic disease; discussion of the key unknowns; suggested ways that measures of mitochondrial dysfunction might be incorporated into HIV research studies.

RECENT FINDINGS

Recent data suggest that mitochondrial dysfunction in PLWH may not be wholly a legacy effect of historical nucleoside analog reverse transcriptase inhibitor exposures. Research in the non-HIV setting has altered our understanding of the important mediators of mitochondrial dysfunction in ageing.

SUMMARY

Mitochondrial dysfunction is a very plausible driver of adverse ageing phenotypes in some older PLWH. As such it may be a target for therapeutic interventions. Currently, however, there remain considerable uncertainties around the extent of this phenomenon, and its relative importance. Current studies are likely to clarify these questions over the next few years.

Probing the Interface of HIV and Inflammaging

PURPOSE OF REVIEW

Systemic inflammation increases as a consequence of aging (inflammaging) and contributes to age-related morbidities. Inflammation in people living with HIV is elevated compared with the general population even after prolonged suppression of viremia with anti-retroviral therapy. Mechanisms that contribute to inflammation during aging and in treated HIV disease are potentially interactive, leading to an exaggerated inflammatory phenotype in people with HIV.

RECENT FINDINGS

Recent studies highlight roles for anti-retroviral therapy, co-infections, immune system alterations, and microbiome perturbations as important contributors to HIV-associated inflammation. These factors likely contribute to increased risk of age-related morbidities in people living with HIV. Understanding mechanisms that exaggerate the inflammaging process in people with HIV may lead to improved intervention strategies, ultimately, extending both lifespan and healthspan.

Distribution of body fat is associated with physical performance of male amateur triathlon athletes

BACKGROUND

Endurance sports are strongly associated with maximum oxygen uptake, anaerobic threshold, running economy and body fat percentage. Despite the importance for performance of the low-fat mass being a consensus in the literature, there are no data about the importance of the pattern of fat distribution. Therefore, the aim of the present study was to investigate the association between fat mass distribution with triathlon performance and physiological determinants of performance: maximal oxygen consumption (VO2max), ventilatory threshold (AT) and running economy (RE), and to verify the predictive value for performance of gynoid or android fat mass distribution.

METHODS

Thirty-nine triathletes (38.8±6.9 years, 174.8±6.5cm and 74.3±8.8kg) were evaluated for anthropometric (total body mass, fat mass, lean mass, android and gynoid fat mass) and physiological (VO2max, AT and RE) parameters. Split and overall race times were registered.

RESULTS

Overall race time relationship with gynoid fat mass (r=.529, p<.05) was classified as moderate higher than and with android fat mass (r=.416, p<.05) was classified as low. All split times and overall race time presented significant positive correlation with only total fat mass (%) (r =.329 to .574, p<.05) and with gynoid fat mass (%) (r=.359 to .529, p<.05). Overall race time can be better predicted by gynoid fat mass (ß=0.529, t=4.093, p<0.001, r2=0.28) than by android fat mass (ß =0.416, t=2.997, p=0.005, r2=0.17).

CONCLUSIONS

Fat mass distribution is associated with triathlon performance, and the gynoid fat pattern is worse for triathlon performance than the android pattern.

Changes in central adipose tissue after switching to integrase inhibitors

Background: Treatment with integrase strand transfer inhibitors (INSTIs) has been associated with excess weight gain, however the long-term effect of INSTI-based regimens on adipose tissue (AT) compartments remains unknown.Objectives: To evaluate the effect of switching to an INSTI on visceral (VAT) and subcutaneous (SAT) AT in virologically-suppressed adults with HIV.Methods: We performed a retrospective observational cohort study of ART experienced adults referred to the metabolic Clinic of the University of Modena and Reggio Emilia who had ≥2 assessments of body composition by abdominal computed tomography. An interrupted time series model with mixed-effect model incorporated was used to calculate VAT and SAT change rate, adjusting for smoking status, use of alcohol, and physical activity.Results: A total of 698 patients were included: 156 who switched to an INSTI-based regimen and 542 who did not. After switch to INSTI, mean SAT area increased approximately 3-fold (before 0.27 vs after 0.73 cm²/month; p = 0.011), and VAT area 7-fold (0.18 vs 1.30 cm²/month; p < 0.001).Conclusions: Among PLWH on ART, both SAT and VAT gain accelerated after switching to an INSTI-based regimen. The associations between INSTIs and central adiposity require further investigation.

HIV infection and coronary heart disease: mechanisms and management

Antiretroviral therapy has largely transformed HIV infection into a chronic disease condition. As such, physicians and other providers caring for individuals living with HIV infection need to be aware of the potential cardiovascular complications of HIV infection and the nuances of how HIV infection increases the risk of cardiovascular diseases, including acute myocardial infarction, stroke, peripheral artery disease, heart failure and sudden cardiac death, as well as how to select available therapies to reduce this risk. In this Review, we discuss the epidemiology and clinical features of cardiovascular disease, with a focus on coronary heart disease, in the setting of HIV infection, which includes a substantially increased risk of myocardial infarction even when the HIV infection is well controlled. We also discuss the mechanisms underlying HIV-associated atherosclerotic cardiovascular disease, such as the high rates of traditional cardiovascular risk factors in patients with HIV infection and HIV-related factors, including the use of antiretroviral therapy and chronic inflammation in the setting of effectively treated HIV infection. Finally, we highlight available therapeutic strategies, as well as approaches under investigation, to reduce the risk of cardiovascular disease and lower inflammation in patients with HIV infection.

Associations between subcutaneous fat density and systemic inflammation differ by HIV serostatus and are independent of fat quantity

OBJECTIVES

Adipose tissue (AT) density measurement may provide information about AT quality among people living with HIV. We assessed AT density and evaluated relationships between AT density and immunometabolic biomarker concentrations in men with HIV.

DESIGN

Cross-sectional analysis of men enrolled in the Multicenter AIDS Cohort Study.

METHODS

Abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) density (Hounsfield units, HU; less negative = more dense) were quantified from computed tomography (CT) scans. Multivariate linear regression models described relationships between abdominal AT density and circulating biomarker concentrations.

RESULTS

HIV+ men had denser SAT (-95 vs -98 HU HIV-, P < 0.001), whereas VAT density was equivalent by HIV serostatus men (382 HIV-, 462 HIV+). Historical thymidine analog nucleoside reverse transcriptase inhibitor (tNRTI) use was associated with denser SAT but not VAT. In adjusted models, a 1 s.d. greater SAT or VAT density was associated with higher levels of adiponectin, leptin, HOMA-IR and triglyceride:HDL cholesterol ratio and lower hs-CRP concentrations in HIV- men. Conversely, in HIV+ men, each s.d. greater SAT density was not associated with metabolic parameter improvements and was significantly (P < 0.05) associated with higher systemic inflammation. Trends toward higher inflammatory biomarker concentrations per 1 s.d. greater VAT density were also observed among HIV+ men.

CONCLUSIONS

Among men living with HIV, greater SAT density was associated with greater systemic inflammation independent of SAT area. AT density measurement provides additional insight into AT density beyond measurement of AT quantity alone, and may have implications for metabolic disease risk.

The association between neck adiposity and long-term outcome

Anthropometric indices of obesity (e.g. body mass index, waist circumference and neck circumference) are associated with poor long-term cardiovascular outcome. Prior studies have associated neck circumference and central body adiposity. We explored the association between neck fat volume (NFV) and long-term cardiovascular outcome. The study provides a retrospective analysis of all patients undergoing computerized tomography angiography for suspected cerebrovascular accident between January and December 2013. NFV was assessed by three dimensional reconstructions and was adjusted to height to account for differences in body sizes, thus yielding the NFV/height ratio (NHR). Univariate and multivariate analysis were utilized to explore the association between various indices including NHR and all-cause mortality. The analysis included 302 patients. The average age was 61.9±14.3 years, 60.6% of male gender. Diabetes mellitus, hypertension and cardiovascular disease were frequent in 31.5%, 69.9%, and 72.2% of patients, respectively. The median NHR was 492.53cm² [IQR 393.93–607.82]. Median follow up time was 41.2 months, during which 40 patients (13.2%) died. Multivariate analysis adjusting for age, sex, and diabetes mellitus indicated an independent association between the upper quartile of NHR and all-cause mortality (hazard ratio = 2.279; 95% CI = 1.209–4.299; p = .011). NHR is a readily available anthropometric index which significantly correlated with poor long-term outcome. Following validation in larger scale studies, this index may serve a risk stratifying tool for cardiovascular disease and future outcome.

Comparison of visceral fat measurement by dual-energy X-ray absorptiometry to computed tomography in HIV and non-HIV

Background/Objectives

Individuals with HIV are susceptible to visceral fat accumulation, which confers an increased risk of cardiometabolic disease. Advanced software to ascertain visceral fat content from dual-energy X-ray absorptiometry (DXA) has not been validated among this population. We sought to compare DXA with computed tomography (CT) in the measurement of visceral fat cross-sectional area (VAT) in HIV and non-HIV using Bland–Altman analyses.

Subjects/Methods

Data were combined from five previously conducted studies of individuals with HIV (n = 313) and controls without HIV (n = 144) in which paired DXA and CT scans were available. In cross-sectional analyses, DXA-VAT was compared with CT-VAT among participants with and without HIV. In longitudinal analyses, changes in VAT over time were compared between DXA and CT among participants with and without HIV receiving no intervention over 12 months and among individuals with HIV receiving tesamorelin—a medication known to reduce VAT—over 6 months.

Results

In HIV, DXA underestimated VAT compared with CT among individuals with increased visceral adiposity. The measurement bias was −9 ± 47 cm² overall, but became progressively larger with greater VAT (P < 0.0001), e.g., −61 ± 58 cm² among those with VAT ≥ 200 cm². Sex-stratified analyses revealed that the relationship between VAT and measurement bias was especially pronounced in men (P < 0.0001). Longitudinally, DXA underestimated changes in VAT, particularly among those at the extremes of VAT gain or loss (P < 0.0001). In contrast to the cross-sectional findings, the tendency for DXA to underestimate longitudinal changes in VAT was evident in both men and women. Analogous findings were seen among controls in cross-sectional and longitudinal analyses.

Conclusions

DXA underestimated VAT relative to CT in men with and without HIV, who had increased visceral adiposity. DXA also underestimated changes in VAT over time in men and women, irrespective of HIV status. DXA-VAT should be used with caution among both HIV and non-HIV-infected populations.

Neck circumference in relation to glycemic parameters: a systematic review and meta-analysis of observational studies

BACKGROUND

Recent studies have suggested that neck circumference (NC) is a supplemental screening measure for diagnosing metabolic complications and might be associated with glycemic parameters. The aim of the present study was to to evaluate the association between NC and glycemic parameters.

METHODS

We systematically searched the electronic databases (including MEDLINE, Scopus, EMBASE, and Google scholar) up to April 2018. Observational studies that reported correlation coefficient between NC and glycemic parameters were included in the analysis. A random effects model was used to estimate overall Fisher's Z and 95% confidence interval of glycemic parameters including fasting plasma glucose (FBG), serum fasting insulin level, homeostasis model assessment-estimated insulin resistance (HOMA-IR) and glycated hemoglobin (HbA1c).

RESULTS

A total of 21 studies (44,031 participants) were eligible for including in the systematic review and meta-analysis. Significant correlations were found between NC and FBG (Fisher's Z = 0.18; 95% CI 0.16, 0.21), serum fasting insulin level (Fisher's Z = 0.34; 95% CI 0.26, 0.41), HOMA-IR (Fisher's Z = 0.36; 95% CI 0.29, 0.43) and HbA1c (Fisher's Z = 0.14; 95% CI 0.09, 0.20). Meta-regression analysis showed that NC were marginally associated with FBG in a linear manner (β = 0.008, P = 0.09); but not related to serum fasting insulin level, HOMA-IR, and HbA1c.

CONCLUSIONS

This meta-analysis of cross-sectional studies showed that NC was positively correlated with glycemic parameters including FBG, serum fasting insulin level, HOMA-IR, and HbA1c. Further investigations with prospective design are required to confirm these findings.

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

Background

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

Methods

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

Results

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

Conclusions

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

Inflammageing: chronic inflammation in ageing, cardiovascular disease, and frailty

Most older individuals develop inflammageing, a condition characterized by elevated levels of blood inflammatory markers that carries high susceptibility to chronic morbidity, disability, frailty, and premature death. Potential mechanisms of inflammageing include genetic susceptibility, central obesity, increased gut permeability, changes to microbiota composition, cellular senescence, NLRP3 inflammasome activation, oxidative stress caused by dysfunctional mitochondria, immune cell dysregulation, and chronic infections. Inflammageing is a risk factor for cardiovascular diseases (CVDs), and clinical trials suggest that this association is causal. Inflammageing is also a risk factor for chronic kidney disease, diabetes mellitus, cancer, depression, dementia, and sarcopenia, but whether modulating inflammation beneficially affects the clinical course of non-CVD health problems is controversial. This uncertainty is an important issue to address because older patients with CVD are often affected by multimorbidity and frailty - which affect clinical manifestations, prognosis, and response to treatment - and are associated with inflammation by mechanisms similar to those in CVD. The hypothesis that inflammation affects CVD, multimorbidity, and frailty by inhibiting growth factors, increasing catabolism, and interfering with homeostatic signalling is supported by mechanistic studies but requires confirmation in humans. Whether early modulation of inflammageing prevents or delays the onset of cardiovascular frailty should be tested in clinical trials.

Abdominal fat depots, insulin resistance, and incident diabetes mellitus in women with and without HIV infection

OBJECTIVE

The aim of this study was to determine the associations between visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (SAT) mass with homeostatic model assessment-insulin resistance (HOMA-IR) and incidence of diabetes mellitus in women with and without HIV infection.

DESIGN

Cross-sectional design for associations between abdominal fat and HOMA-IR; longitudinal design for associations between abdominal fat and incident diabetes.

METHODS

We assessed associations between dual X-ray absorptiometry scan-derived VAT and SAT with HOMA-IR in a subsample from the Women's Interagency HIV Study (n = 226 with and n = 100 without HIV) using linear regression. We evaluated associations of VAT, SAT and HOMA-IR with incident diabetes mellitus using Cox proportional hazards models.

RESULTS

VAT mass was positively associated with log HOMA-IR in fully adjusted linear regression models stratified by HIV serostatus, including adjustment for SAT. During median follow-up of 10.6 years, incidence of diabetes was 1.63 [95% confidence interval (95% CI) 1.15-2.31] and 1.32 [95% CI 0.77-2.28] cases per 100 person-years in women with and without HIV (P = 0.52). In a fully adjusted model, baseline VAT (hazard ratio 2.64 per kg; 95% CI 1.14-6.12; P = 0.023) and SAT (hazard ratio 1.34 per kg; 95% CI 0.73-2.45; P = 0.35) were associated with incident diabetes, but the latter was not statistically significant.

CONCLUSION

VAT mass was independently associated with HOMA-IR in women with and without HIV and was independently associated with future development of diabetes.

Randomized, Placebo-Controlled Trial to Evaluate Effects of Eplerenone on Metabolic and Inflammatory Indices in HIV

CONTEXT

HIV-infected individuals demonstrate increased renin-angiotensin-aldosterone system activation in association with visceral adiposity, insulin resistance, and inflammation. A physiologically based treatment approach targeting mineralocorticoid receptor (MR) blockade may improve metabolic and inflammatory indices in HIV.

OBJECTIVE

To investigate effects of eplerenone on insulin sensitivity, inflammatory indices, and other metabolic parameters in HIV.

DESIGN

Six-month, double-blind, randomized, placebo-controlled trial.

SETTING

Academic clinical research center.

PARTICIPANTS

HIV-infected individuals with increased waist circumference and abnormal glucose homeostasis.

INTERVENTION

Eplerenone 50 mg or placebo daily.

OUTCOME

The primary end point was change in insulin sensitivity measured by the euglycemic-hyperinsulinemic clamp technique. Secondary end points included change in body composition and inflammatory markers.

RESULTS

Forty-six individuals were randomized to eplerenone (n = 25) vs placebo (n = 21). Eplerenone did not improve insulin sensitivity [0.48 (-1.28 to 1.48) vs 0.43 (-1.95 to 2.55) mg/min/μIU/mL insulin; P = 0.71, eplerenone vs placebo] when measured by the gold standard euglycemic-hyperinsulinemic clamp technique. Intramyocellular lipids (P = 0.04), monocyte chemoattractant protein-1 (P = 0.04), and high-density lipoprotein (P = 0.04) improved among those randomized to eplerenone vs placebo. Trends toward decreases in interleukin-6 (P = 0.10) and high-sensitivity C-reactive protein (P = 0.10) were also seen with eplerenone vs placebo. Plasma renin activity and aldosterone levels increased in the eplerenone vs placebo-treated group, demonstrating expected physiology. MR antagonism with eplerenone was well tolerated among the HIV population, with no considerable changes in blood pressure or potassium.

CONCLUSION

MR blockade may improve selected metabolic and inflammatory indices in HIV-infected individuals. Further studies are necessary to understand the clinical potential of MR antagonism in HIV.

Unanticipated increases in hepatic steatosis among human immunodeficiency virus patients receiving mineralocorticoid receptor antagonist eplerenone for non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease is common in human immunodeficiency virus, but there are no approved therapies. The aim of this open-label proof-of-concept study was to determine the effect of the mineralocorticoid receptor antagonist eplerenone on hepatic fat in human immunodeficiency virus-infected patients with hepatic fat ≥5% by magnetic resonance spectroscopy.

METHODS

Five subjects received eplerenone (25 mg daily × 1 week followed by 50 mg daily × 23 weeks). Laboratory tests were done at each visit, and the primary endpoint, change in hepatic fat content, was determined by MRI spectroscopy at baseline and week 24.

RESULTS

The study was stopped early after observing unexpected significant increases in hepatic fat at week 24 (mean increase 13.0 ± 7.3%, P = .02). The increases in steatosis were accompanied by a tendency for transaminase values to decrease (alanine aminotransferase mean change -14 ± 16 IU/L, P = .14). There were no consistent changes in other metabolic parameters or blood pressure. Repeat assessment of hepatic steatosis 1-2 months after stopping study medication revealed improvements in steatosis towards baseline values.

CONCLUSIONS

The unexpected observation of increased hepatic steatosis with the administration of eplerenone led to early termination of the investigation. While limited because of the small number of participants and the open-label design, this study provides data to suggest that mineralocorticoid receptor antagonism with eplerenone may not be an effective approach to treat hepatic steatosis in human immunodeficiency virus or the general population. Additional research is needed to determine the pathophysiological mechanism behind these unanticipated observations.

Adipose Tissue in HIV Infection

HIV infection and antiretroviral therapy (ART) treatment exert diverse effects on adipocytes and stromal-vascular fraction cells, leading to changes in adipose tissue quantity, distribution, and energy storage. A HIV-associated lipodystrophic condition was recognized early in the epidemic, characterized by clinically apparent changes in subcutaneous, visceral, and dorsocervical adipose depots. Underlying these changes is altered adipose tissue morphology and expression of genes central to adipocyte maturation, regulation, metabolism, and cytokine signaling. HIV viral proteins persist in circulation and locally within adipose tissue despite suppression of plasma viremia on ART, and exposure to these proteins impairs preadipocyte maturation and reduces adipocyte expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) and other genes involved in cell regulation. Several early nucleoside reverse transcriptase inhibitor and protease inhibitor antiretroviral drugs demonstrated substantial adipocyte toxicity, including reduced mitochondrial DNA content and respiratory chain enzymes, reduced PPAR-γ and other regulatory gene expression, and increased proinflammatory cytokine production. Newer-generation agents, such as integrase inhibitors, appear to have fewer adverse effects. HIV infection also alters the balance of CD4+ and CD8+ T cells in adipose tissue, with effects on macrophage activation and local inflammation, while the presence of latently infected CD4+ T cells in adipose tissue may constitute a protected viral reservoir. This review provides a synthesis of the literature on how HIV virus, ART treatment, and host characteristics interact to affect adipose tissue distribution, immunology, and contribution to metabolic health, and adipocyte maturation, cellular regulation, and energy storage. © 2017 American Physiological Society. Compr Physiol 7:1339-1357, 2017.

Upper Body Subcutaneous Fat Is Associated with Cardiometabolic Risk Factors

BACKGROUND

Upper body subcutaneous fat is a distinct fat depot that may confer increased cardiometabolic risk. We examined the cross-sectional associations between upper body subcutaneous fat volume and cardiometabolic risk factors.

METHODS

Participants were patients from the Framingham Heart Study who underwent multi-detector computed tomography between 2008 and 2011. Sex-specific multivariable-adjusted regression analyses were conducted. Covariates included age, ethnicity, smoking status, alcohol intake, physical activity, postmenopausal status, and hormone replacement therapy. Additional models included adjustment for body mass index (BMI), neck circumference, or abdominal visceral adipose tissue.

RESULTS

There were 2306 participants (mean age 60 years, 54.4% women) included. Mean upper body subcutaneous fat was 309.9 cm³ in women and 345.6 cm³ in men. Higher upper body subcutaneous fat volume was associated with adverse cardiometabolic risk factors. In women and men, each additional 50-cm³ increment in upper body subcutaneous fat was associated with a 3.23 and 2.65 kg/m² increase in BMI; 2.16 and 0.88 mm Hg increase in systolic blood pressure; 2.53 and 1.66 mg/dL increase in fasting plasma glucose; 0.12 and 0.11 mg/dL increase in log triglycerides; and 4.17 and 3.68 mg/dL decrease in high-density lipoprotein cholesterol, respectively (all P ≤.008). Similar patterns were observed with prevalent cardiometabolic risk factors. These associations remained significant after additional adjustment for BMI, neck circumference, or abdominal visceral adipose tissue.

CONCLUSIONS

Higher upper body subcutaneous fat is cross-sectionally associated with adverse cardiometabolic risk factors. Our findings underscore the importance of subcutaneous adiposity in the upper body region that may provide a better understanding of the pathogenic properties of obesity in the development of cardiometabolic sequelae.

HIV and its relationship to insulin resistance and lipid abnormalities

Antiretroviral therapy has revolutionized the care of people with human immunodeficiency virus (HIV) by reducing morbidity and mortality from acquired immunodeficiency syndrome-related conditions. Despite longer life expectancy, however, HIV-infected individuals continue to have a higher risk of death compared with the general population. This has been attributed to the increasing incidence of noncommunicable diseases, in particular, atherosclerotic cardiovascular diseases. This is driven, in part, by the emergence of metabolic disorders, particularly dyslipidemia, insulin resistance, and lipodystrophy, in those on antiretroviral therapy. The pathogenesis of these metabolic derangements is complex and multifactorial, and could be a consequence of an interplay between traditional age-related risk factors, HIV infection, antiretroviral therapy effects, and the inflammatory state and immune activation in this population. Understanding the contributions of each of these factors could not just impact the current management of these individuals and help mitigate the risk for premature cardiovascular disease, but also shape the future direction of research in HIV.

Ageing and inflammation in patients with HIV infection

Nowadays, HIV⁺ patients have an expected lifespan that is only slightly shorter than healthy individuals. For this reason, along with the fact that infection can be acquired at a relatively advanced age, the effects of ageing on HIV⁺ people have begun to be evident. Successful anti-viral treatment is, on one hand, responsible for the development of side effects related to drug toxicity; on the other hand, it is not able to inhibit the onset of several complications caused by persistent immune activation and chronic inflammation. Therefore, patients with a relatively advanced age, i.e. aged more than 50 years, can experience pathologies that affect much older citizens. HIV⁺ individuals with non-AIDS-related complications can thus come to the attention of clinicians because of the presence of neurocognitive disorders, cardiovascular diseases, metabolic syndrome, bone abnormalities and non-HIV-associated cancers. Chronic inflammation and immune activation, observed typically in elderly people and defined as 'inflammaging', can be present in HIV⁺ patients who experience a type of premature ageing, which affects the quality of life significantly. This relatively new condition is extremely complex, and important factors have been identified as well as the traditional behavioural risk factors, e.g. the toxicity of anti-retroviral treatments and the above-mentioned chronic inflammation leading to a functional decline and a vulnerability to injury or pathologies. Here, we discuss the role of inflammation and immune activation on the most important non-AIDS-related complications of chronic HIV infection, and the contribution of aging per se to this scenario.

Anatomic Fat Depots and Coronary Plaque Among Human Immunodeficiency Virus-Infected and Uninfected Men in the Multicenter AIDS Cohort Study

Methods. In a cross-sectional substudy of the Multicenter AIDS Cohort Study, noncontrast cardiac computed tomography (CT) scanning for coronary artery calcium (CAC) scoring was performed on all men, and, for men with normal renal function, coronary CT angiography (CTA) was performed. Associations between fat depots (visceral adipose tissue [VAT], abdominal subcutaneous adipose tissue [aSAT], and thigh subcutaneous adipose tissue [tSAT]) with coronary plaque presence and extent were assessed with logistic and linear regression adjusted for age, race, cardiovascular disease (CVD) risk factors, body mass index (BMI), and human immunodeficiency virus (HIV) parameters.

Results. Among HIV-infected men (n = 597) but not HIV-uninfected men (n = 343), having greater VAT was positively associated with noncalcified plaque presence (odds ratio [OR] = 1.04, P < .05), with a significant interaction (P < .05) by HIV serostatus. Human immunodeficiency virus-infected men had lower median aSAT and tSAT and greater median VAT among men with BMI <25 and 25–29.9 kg/m². Among HIV-infected men, VAT was positively associated with presence of coronary plaque on CTA after adjustment for CVD risk factors (OR = 1.04, P < .05), but not after additional adjustment for BMI. There was an inverse association between aSAT and extent of total plaque among HIV-infected men, but not among HIV-uninfected men. Lower tSAT was associated with greater CAC and total plaque score extent regardless of HIV serostatus.

Conclusions. The presence of greater amounts of VAT and lower SAT may contribute to increased risk for coronary artery disease among HIV-infected persons.

Neck circumference and prehypertension: the cardiometabolic risk in Chinese study

BACKGROUND

We have previously found that neck circumference was related to insulin resistance, a risk factor for hypertension in Chinese. Little is known about whether high neck circumference is associated with elevated blood pressure.

METHOD

The study samples were from a community-based health examination survey in central China. In total, 1709 men and women with neck circumference measurement were included. We analysed the associations between neck circumference and the risk of prehypertension.

RESULTS

Although neck circumference was strongly associated with SBP/DBP in a univariate analysis, it was no longer associated with SBP and the association was much weaker with DBP when the association was adjusted for BMI or waist circumference. Similarly, high neck circumference was significantly related to an increased risk of prehypertension [odds ratio 1.254; 95% confidence interval (95% CI) 1.171-1.343] in a univariate analysis, and the association became marginal in models further adjusting for BMI or waist.

CONCLUSION

Our data suggest that neck circumference as predictor for prehypertension is not obvious given the moderate improvement of disease prediction.

Physical Activity and Its Association with Insulin Resistance in Multicenter AIDS Cohort Study Men

The association between physical activity (PA), degree of insulin resistance (IR), and HIV infection is unclear. We hypothesized that PA might differentially affect the degree of IR through the direct and indirect influences of HIV, antiretroviral medications, and sociodemographic characteristics. The International Physical Activity Questionnaire (IPAQ) was administered to Multicenter AIDS Cohort Study (MACS) participants from 4/2010 to 3/2011 to generate metabolic equivalents (METs) total score and PA category. We determined the concurrent homeostatic model assessment IR (mmol/liter) (HOMA-IR) value from fasting glucose and insulin. We examined the HIV-PA relationship using quantile regression and the HIV-PA-HOMA-IR value relationship using linear regression. Among the 1,281 men, the proportions of men in the low (25% in HIV(+) vs. 23% in HIV(-)), moderate (26% vs. 27%), and high (49% vs. 49%) PA categories were similar by HIV status. The HOMA-IR value was higher among the HIV(+) men (p<0.001), and both HIV infection and low PA were associated with a higher degree of IR (p<0.0001 and p=0.0007). However, the PA-HOMA-IR value interaction was not different by HIV status. The HOMA-IR value was higher among HIV(+) men although the PA was similar. It is unknown if more exercise will overcome the metabolic derangements associated with HIV and its treatment.

Serum adiponectin in HIV-1 and hepatitis C virus mono- and co-infected Kenyan injection drug users

Adiponectin is an important marker of anthropometric profiles of adipose tissue. However, association of adiponectin and adiposity in HIV mono- and co-infected and hepatitis (HCV) injection drug users (IDUs) has not been elucidated. Therefore, the relationship of total adiponectin levels with anthropometric indices of adiposity was examined in HIV mono-infected (anti-retroviral treatment, ART-naive, n=16 and -experienced, n=34); HCV mono-infected, n=36; HIV and HCV co-infected (ART-naive, n=5 and -experienced, n=13); uninfected, n=19 IDUs; and healthy controls, n=16 from coastal Kenya. Anthropometric indices of adiposity were recorded and total circulating adiponectin levels were measured in serum samples using enzyme-linked immunosorbent assay. Adiponectin levels differed significantly amongst the study groups (P<0.0001). Post-hoc analyses revealed decreased levels in HIV mono-infected ART-naive IDUs in comparison to uninfected IDUs (P<0.05) and healthy controls (P<0.05). However, adiponectin levels were elevated in HCV mono-infected IDUs relative to HIV mono-infected ART-naive (P<0.001) and -experienced (P<0.001) as well as HIV and HCV co-infected ART-naive (P<0.05) IDUs. Furthermore, adiponectin correlated with weight (ρ=0.687; P=0.003) and BMI (ρ=0.598; P=0.014) in HIV mono-infected ART-naive IDUs; waist circumference (ρ=-0.626; P<0.0001), hip (ρ=-0.561; P=0.001) circumference, and bust-to-waist ratio (ρ=0.561; P=0.001) in HIV mono-infected ART-experienced IDUs; waist girth (ρ=0.375; P=0.024) in HCV mono-infected IDUs; and waist-to-hip ratio (ρ=-0.872; P=0.048) in HIV and HCV co-infected ART-naive IDUs. Altogether, these results suggest suppression of adiponectin production in treatment-naive HIV mono-infected IDUs and that circulating adiponectin is a useful surrogate marker of altered adiposity in treatment-naive and -experienced HIV and HCV mono- and co-infected IDUs.

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.

Evaluation of neck circumference as a predictor of central obesity and insulin resistance in Chinese adults

OBJECTIVES

To evaluate whether neck circumference (NC) could be used as a valid and effective method for identifying obesity and insulin resistance (IR) in Chinese adults.

METHODS

A total of 3307 adults aged 20-65 years were randomly recruited from two communities of Tongzhou, Beijing. Height, weight, waist circumference (WC), hip circumference (HC), neck circumference (NC), blood pressure, fasting plasma glucose (FPG), fasting serum insulin (FINS), total cholesterol (TC), serum triglyceride (TG), High-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and Urinary albumin (UAlb) were measured. Pearson correlation coefficient was used to explore the relationship between NC and other measurements. Furthermore, the best cutoff values of NC for central obesity identification were determined by applying the receiver operating characteristic (ROC) curve analysis.

RESULTS

NC correlated positively with BMI, SBP and WC In both sexes. Both WC and NC correlated significantly positively with IR. A positive correlation between NC and FPG as well as a negative correlation between NC and HDL were found in obese men. NC≥38.5 cm for men and ≥34.5 cm for women were determined to be the best cutoff levels for identifying subjects with central obesity, with 82.9% accuracy for men and 79.9% accuracy for women.

CONCLUSIONS

NC correlated positively with BMI and WC in both genders, indicating that NC could be used as a valid marker for both overall obesity and central obesity. In addition, measuring NC was shown to be a useful test for IR identification. Large number of NC is suggested to be associated with high risk of developing metabolic disorders, such as diabetes and dyslipidemia.

Development and reproducibility of a computed tomography-based measurement for upper body subcutaneous neck fat

Background

Upper body subcutaneous neck fat (UBSF) is a unique fat depot anatomically separate from visceral abdominal fat that appears to be associated with cardiometabolic risk above and beyond generalized adiposity. We sought to develop a protocol to quantify UBSF using multidetector computed tomography measurements.

Methods and Results

Protocol development was performed in participants from the Framingham Heart Study who had participated in the multidetector computed tomography scanning substudy, consisting of chest scans. Volumetric assessment of UBSF was defined by 40 contiguous 0.625‐mm slices superior to the body of the sternum. The reader manually traced the chest to identify total neck fat. Breast tissue exterior to the chest wall was excluded. Subcutaneous and visceral fat volumes were obtained using standard protocols. Age‐ and sex‐adjusted Pearson correlation coefficients were used to assess the association among UBSF, traditional adiposity measures, and cardiometabolic risk factors. Inter‐ and intrareader reproducibility was assessed using intraclass correlation coefficients. Volumetric assessments were obtained in 92 participants because 8 scans were not readable (51% women; mean age: 59 years [women], 58 years [men]). The mean volume of UBSF was 310 cm³ for women and 345 cm³ for men. Intra‐ and interreader class correlation coefficients were 0.99 and 0.99, respectively. UBSF was correlated with waist circumference (r=0.90), neck circumference (r=0.75), body mass index (r=0.89), subcutaneous adipose tissue (r=0.87), and visceral adipose tissue (r=0.86).

Conclusions

UBSF can be quantified reproducibly using computed tomography in a community‐dwelling sample from the Framingham Heart Study.

RAAS Activation Is Associated With Visceral Adiposity and Insulin Resistance Among HIV-infected Patients

CONTEXT

Little is known about renin-angiotensin-aldosterone system (RAAS) activation in relationship to visceral adipose tissue (VAT) accumulation in HIV-infected patients, a population at significant risk for insulin resistance and other metabolic disease.

DESIGN

Twenty HIV and 10 non-HIV-infected subjects consumed a standardized low sodium or liberal sodium diet to stimulate or suppress the RAAS, respectively. RAAS parameters were evaluated in response to each diet and a graded angiotensin II infusion. Further analyses were performed after groups were substratified by median VAT measured by magnetic resonance imaging.

RESULTS

Aldosterone concentrations during the low-sodium diet were higher in HIV than non-HIV-infected subjects [13.8 (9.7, 30.9) vs 9.2 (7.6, 13.6) ng/dL, P = .03] and increased across groups stratified by visceral adipose tissue (VAT) [8.5 (7.1, 12.8), 9.2 (8.1, 21.5), 11.4 (9.4, 13.8), and 27.2 (13.0, 36.9) ng/dL in non-HIV-infected without increased VAT, non-HIV-infected with increased VAT, HIV-infected without increased VAT, HIV-infected with increased VAT, respectively, overall trend P = .02]. Under this condition, plasma renin activity [3.50 (2.58, 4.65) vs 1.45 (0.58, 2.33) ng/mL · h, P = .002] was higher among the HIV-infected subjects with vs without increased VAT. Differences in the suppressibility of plasma renin activity by graded angiotensin infusion were seen stratifying by VAT among the HIV-infected group (P < .02 at each dose). In addition, aldosterone (P = .007) was an independent predictor of insulin resistance in multivariate modeling, controlling for VAT and adiponectin.

CONCLUSION

These data suggest excess RAAS activation in relationship to visceral adiposity in HIV-infected patients that may independently contribute to insulin resistance. Mineralocorticoid blockade may have therapeutic potential to reduce metabolic complications in HIV-infected patients with increased visceral adiposity.

Prediction of Android and Gynoid Body Adiposity via a Three-dimensional Stereovision Body Imaging System and Dual-Energy X-ray Absorptiometry

OBJECTIVE

Current methods for measuring regional body fat are expensive and inconvenient compared to the relative cost-effectiveness and ease of use of a stereovision body imaging (SBI) system. The primary goal of this research is to develop prediction models for android and gynoid fat by body measurements assessed via SBI and dual-energy x-ray absorptiometry (DXA). Subsequently, mathematical equations for prediction of total and regional (trunk, leg) body adiposity were established via parameters measured by SBI and DXA.

METHODS

A total of 121 participants were randomly assigned into primary and cross-validation groups. Body measurements were obtained via traditional anthropometrics, SBI, and DXA. Multiple regression analysis was conducted to develop mathematical equations by demographics and SBI assessed body measurements as independent variables and body adiposity (fat mass and percentage fat) as dependent variables. The validity of the prediction models was evaluated by a split sample method and Bland-Altman analysis.

RESULTS

The R(2) of the prediction equations for fat mass and percentage body fat were 93.2% and 76.4% for android and 91.4% and 66.5% for gynoid, respectively. The limits of agreement for the fat mass and percentage fat were -0.06 ± 0.87 kg and -0.11% ± 1.97% for android and -0.04 ± 1.58 kg and -0.19% ± 4.27% for gynoid. Prediction values for fat mass and percentage fat were 94.6% and 88.9% for total body, 93.9% and 71.0% for trunk, and 92.4% and 64.1% for leg, respectively.

CONCLUSIONS

The three-dimensional (3D) SBI produces reliable parameters that can predict android and gynoid as well as total and regional (trunk, leg) fat mass.

Adiponectin and interleukin-6, but not adipose tissue, are associated with worse neurocognitive function in HIV-infected men

BACKGROUND

Generalized obesity has been associated with cognitive decline, a process potentially mediated by adipocytokines. The effects of regional adipose tissue (AT) on cognition, however, are not well understood. We explored cross-sectional relationships between regional AT, adipocytokines, inflammatory markers and neuropsychological (NP) test scores among HIV+ and HIV- men enrolled in the Multicenter AIDS Cohort Study.

METHODS

Visceral, subcutaneous abdominal and subcutaneous thigh AT areas were quantified by computed tomography (CT). NP tests (Trail Making Test parts A and B, and Symbol-Digit Modalities) obtained within 2 years of CT screened for psychomotor speed and executive function. Adiponectin, leptin, interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP) were measured.

RESULTS

Of 509 HIV+ and 271 HIV- participants, HIV+ men (98% on antiretroviral therapy, 81% HIV-1 RNA<50 copies/ml) had lower median subcutaneous AT and adiponectin levels and higher hs-CRP levels, but visceral AT, body mass index, IL-6 and NP scores did not vary by HIV serostatus. In multivariable analysis, older age, ≤ high school education and African American race, but not AT area or site, were associated with worse NP test scores among all participants. In HIV+ only, higher adiponectin and IL-6 were associated with worse cognitive function independent of AT area. No HIV-specific factors were associated with NP test scores.

CONCLUSIONS

Demographic factors were associated with NP test performance, but regional adiposity was not. In HIV+ only, higher adiponectin and IL-6 were associated with worse NP test scores, supporting a role for chronic inflammation and adipocytokine imbalance in neurocognitive decline in HIV+ persons.

Association of HIV and ART with cardiometabolic traits in sub-Saharan Africa: a systematic review and meta-analysis

Background Sub-Saharan Africa (SSA) has the highest burden of HIV in the world and a rising prevalence of cardiometabolic disease; however, the interrelationship between HIV, antiretroviral therapy (ART) and cardiometabolic traits is not well described in SSA populations.

Methods We conducted a systematic review and meta-analysis through MEDLINE and EMBASE (up to January 2012), as well as direct author contact. Eligible studies provided summary or individual-level data on one or more of the following traits in HIV+ and HIV-, or ART+ and ART- subgroups in SSA: body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TGs) and fasting blood glucose (FBG) or glycated hemoglobin (HbA1c). Information was synthesized under a random-effects model and the primary outcomes were the standardized mean differences (SMD) of the specified traits between subgroups of participants.

Results Data were obtained from 49 published and 3 unpublished studies which reported on 29 755 individuals. HIV infection was associated with higher TGs [SMD, 0.26; 95% confidence interval (CI), 0.08 to 0.44] and lower HDL (SMD, −0.59; 95% CI, −0.86 to −0.31), BMI (SMD, −0.32; 95% CI, −0.45 to −0.18), SBP (SMD, −0.40; 95% CI, −0.55 to −0.25) and DBP (SMD, −0.34; 95% CI, −0.51 to −0.17). Among HIV+ individuals, ART use was associated with higher LDL (SMD, 0.43; 95% CI, 0.14 to 0.72) and HDL (SMD, 0.39; 95% CI, 0.11 to 0.66), and lower HbA1c (SMD, −0.34; 95% CI, −0.62 to −0.06). Fully adjusted estimates from analyses of individual participant data were consistent with meta-analysis of summary estimates for most traits.

Conclusions Broadly consistent with results from populations of European descent, these results suggest differences in cardiometabolic traits between HIV-infected and uninfected individuals in SSA, which might be modified by ART use. In a region with the highest burden of HIV, it will be important to clarify these findings to reliably assess the need for monitoring and managing cardiometabolic risk in HIV-infected populations in SSA.

The association of adiposity with kidney function decline among HIV-infected adults: findings from the Fat Redistribution and Metabolic Changes in HIV Infection (FRAM) study

OBJECTIVES

The aim of the study was to investigate the association of adiposity with longitudinal kidney function change in 544 HIV-infected persons in the Study of Fat Redistribution and Metabolic Change in HIV infection (FRAM) cohort over 5 years of follow-up.

METHODS

The regional distribution of muscle and adipose tissue was quantified by whole-body magnetic resonance imaging (MRI), and total adiponectin and leptin levels were measured in serum. Kidney function was assessed using the estimated glomerular filtration rate from serum cystatin C (eGFRCys), obtained at baseline and follow-up. Rapid kidney function decline was defined as annual loss of eGFRCys ≥ 3 mL/min/1.73 m(2) , and incident chronic kidney disease (CKD) was defined as eGFRCys <60 mL/min/1.73 m(2) . Multivariate regression analysis was adjusted for age, race, gender, glucose, antihypertensive use, serum albumin, baseline and change in HIV viral load.

RESULTS

At baseline, mean age was 43 years, mean eGFRCys was 86 mL/min/1.73 m(2) , and 21% of patients had albuminuria. The mean (± standard deviation) eGFRCys decline was -0.11 ± 4.87 mL/min/1.73 m(2) per year; 23% of participants had rapid kidney function decline, and 10% developed incident CKD. The lowest tertile of visceral adipose tissue and the highest tertile of adiponectin were both marginally associated with annual kidney function decline of -0.5 mL/min/1.73 m(2) each, but these associations were not statistically significant after adjustment. We found no statistically significant associations of MRI-measured regional adiposity or serum adipokines with rapid kidney function decline or incident CKD (all P-values>0.1 in adjusted models).

CONCLUSIONS

Contrary to findings in the general population, adiposity did not have a substantial association with longitudinal change in kidney function among HIV-infected persons.

Hypothalamic-pituitary-adrenal axis in HIV infection and disease

HIV infection induces hypothalamic-pituitary-adrenal (HPA) axis derangements. Partial glucocorticoid resistance has been observed in a subset of AIDS patients, possibly owing to HIV-induced altered cytokine secretion and action. Because glucocorticoids have immunomodulatory effects, the severity of the HPA axis disorder could play a central role in disease progression. The characteristic phenotype of AIDS patients (visceral obesity, lipodystrophy) may be owing to effects of HIV proteins on the HPA axis, including changes in glucocorticoid and insulin sensitivity of target tissues, as well as altered cytokine production and interaction with the HPA axis, genetic causes, comorbidities, and, possibly, use of antiretroviral agents.

The natural history of HIV-associated lipodystrophy in the changing scenario of HIV infection

OBJECTIVES

In long-term HIV-infected patients, peripheral lipoatrophy (LA) and central lipohypertrophy (LH) appear to be related to the same insults (virus and antiretroviral drugs), but are likely to be associated with different fat depot physiologies. The objective of this study was to describe the natural history of lipodystrophy assessed using dual energy X-ray absorptiometry (DEXA) and computed tomography (CT) in a large HIV out-patients metabolic clinic.

METHODS

An observational retrospective study was carried out including HIV-infected patients recruited at the Metabolic Clinic of Modena, Modena, Italy, who were assessed for lipodystrophy and had at least two anthropometric evaluations using DEXA for leg fat per cent mass and abdominal CT for visceral adipose tissue (VAT). Factors associated with leg fat per cent and VAT changes were analysed using multivariable generalized estimating equation (GEE) regression models.

RESULTS

A total of 6789 DEXAs and 7566 CT scans were evaluated in the observation period. A total of 1840 patients were included; the mean age was 45.2 ± 7.2 (standard deviation) years, 621 (34%) were women, and the median HIV infection duration was 176 (interquartile range 121-232) years. According to the GEE multivariable regression analysis, leg fat per cent evaluated with DEXA appeared to increase over calendar years (ß = 0.92; P < 0.001); moreover, a progressive increase in VAT was observed in the cohort (ß = 5.69; P < 0.001). No association with antiretroviral drugs was found.

CONCLUSIONS

In our study, neither LA nor LH appeared to be associated with antiretroviral drug exposure. We observed a progressive increase in LH in HIV-infected patients over calendar years. This anthropometric change, together with loss of appendicular lean mass, could describe a physiological aging process in HIV-infected patients.

HIV-associated lipodystrophy: impact of antiretroviral therapy

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

HIV infection and cardiovascular disease

AIMS

With the success of antiretroviral therapy (ART), non-human immunodeficiency virus (HIV)-related comorbidities like cardiovascular diseases (CVDs) are of increasing concern. We describe important recent research developments on the epidemiology of CVD in HIV infection, ART-related metabolic changes, and cardioprotective anti-inflammatory mechanisms, and summarize management strategies for CVD risk reduction.

METHODS AND RESULTS

We systematically identified and analysed systematic reviews and most cited literature published in the last 3 years and supplemented findings with selected evidence based on clinical expertise. Among HIV-infected individuals, the prevalence of CVD risk factors and the risk for CVD is higher compared with HIV negatives. Antiretroviral drugs may induce dyslipidaemia, reduce insulin sensitivity, and promote body fat redistribution that additionally contributes to CVD risk. Some antiretroviral drugs may increase risk for CVD events, but the absolute risk increase is moderate and has to be put into perspective with the massive HIV-related benefits. Sustained HIV suppression reduces systemic inflammatory markers and is associated with a moderate reduction in CVD events. Regular CVD risk assessment and counselling to stop smoking must be regularly done in all HIV-infected individuals. Statins are effective for the treatment of dyslipidaemia in HIV infection, but drug interactions with ART need to be considered.

CONCLUSION

Human immunodeficiency virus-infected individuals are at increased risk for CVD. Timely initiation of ART with consequent viral suppression is likely to reduce CVD events and to offset potential side effects from ART-induced metabolic changes. Reduction in smoking in HIV-infected individuals is a public health priority.

Thirty years of the human immunodeficiency virus epidemic and beyond

After more than 30 years of battling a global epidemic, the prospect of eliminating human immunodeficiency virus (HIV) as the most challenging infectious disease of the modern era is within our reach. Major scientific discoveries about the virus responsible for this immunodeficiency disease state, including its pathogenesis, transmission patterns and clinical course, have led to the development of potent antiretroviral drugs that offer great hopes in HIV treatment and prevention. Although these agents and many others still in development and testing are capable of effectively suppressing viral replication and survival, the medical management of HIV infection at the individual and the population levels remains challenging. Timely initiation of antiretroviral drugs, adherence to the appropriate therapeutic regimens, effective use of these agents in the pre and post-exposure prophylaxis contexts, treatment of comorbid conditions and addressing social and psychological factors involved in the care of individuals continue to be important considerations.

The association between diet and physical activity on insulin resistance in the Women's Interagency HIV Study

OBJECTIVES

To evaluate the association of diet and physical activity with insulin resistance (IR) in HIV-infected and HIV-uninfected women.

METHODS

Cross-sectional analyses of summary dietary measures and physical activity intensity scores obtained from women enrolled in the San Francisco (n = 113) and Chicago (n = 65) Women's Interagency HIV Study (WIHS) sites. IR was estimated using the homeostasis model assessment (HOMA-IR). Stepwise regression models assessed the association of diet and physical activity with HOMA-IR after adjustment for demographic, behavioral, and clinical factors.

RESULTS

Compared with HIV-uninfected women, HIV-infected women were older and more likely to have health insurance. In multivariable analysis including all women, being from San Francisco ( P = 0.005), having a higher mean body mass index (BMI, P < 0.001), and having a higher percent kilocalories from sweets (P = 0.025) were associated with greater HOMA-IR; heavy intensity physical activity (P = 0.006) and annual household income more than $36,000 ( P = 0.02) was associated with a lower HOMA-IR. In analysis limited to HIV-infected women, having a higher body mass index (P < 0.001) and a history of protease inhibitor use (P = 0.002) were significantly associated with higher HOMA-IR; heavy intensity activity (P = 0.06) was marginally associated with lower HOMA-IR and being menopausal (P = 0.05) was marginally associated with higher HOMA-IR.

CONCLUSIONS

Among urban women with or at risk for HIV-infection, heavy intensity physical activity was associated with lower HOMA-IR, whereas higher percent kilocalories from sweets were associated with higher HOMA-IR. Given the overall health benefits of physical activity and a diet low on sugar, these behaviors should be encouraged whenever possible.

Comparison among T1-weighted magnetic resonance imaging, modified dixon method, and magnetic resonance spectroscopy in measuring bone marrow fat

INTRODUCTION

An increasing number of studies are utilizing different magnetic resonance (MR) methods to quantify bone marrow fat due to its potential role in osteoporosis. Our aim is to compare the measurements of bone marrow fat among T1-weighted magnetic resonance imaging (MRI), modified Dixon method (also called fat fraction MRI (FFMRI)), and magnetic resonance spectroscopy (MRS).

METHODS

Contiguous MRI scans were acquired in 27 Caucasian postmenopausal women with a modified Dixon method (i.e., FFMRI). Bone marrow adipose tissue (BMAT) of T1-weighted MRI and bone marrow fat fraction of the L3 vertebra and femoral necks were quantified using SliceOmatic and Matlab. MRS was also acquired at the L3 vertebra.

RESULTS

Correlation among the three MR methods measured bone marrow fat fraction and BMAT ranges from 0.78 to 0.88 (P < 0.001) in the L3 vertebra. Correlation between BMAT measured by T1-weighted MRI and bone marrow fat fraction measured by modified FFMRI is 0.86 (P < 0.001) in femoral necks.

CONCLUSION

There are good correlations among T1-weighted MRI, FFMRI, and MRS for bone marrow fat quantification. The inhomogeneous distribution of bone marrow fat, the threshold segmentation of the T1-weighted MRI, and the ambiguity of the FFMRI may partially explain the difference among the three methods.

Impact of age on markers of HIV-1 disease

Aging is a complicated process characterized by a progressive loss of homeostasis, which results in an increased vulnerability to multiple diseases. HIV-1-infected patients demonstrate a premature aging phenotype and develop certain age-related diseases earlier in their lifespan than what is seen in the general population. Age-related comorbidities may include the development of bone disease, metabolic disorders, neurologic impairment and immunosenescence. Age also appears to have an effect on traditional markers of HIV-1 disease progression, including CD4+ T-cell count and viral load. These effects are not only a consequence of HIV-1 infection, but in many cases, are also linked to antiretroviral therapy. This review summarizes the complex interplay between HIV-1 infection and aging, and the impact that aging has on markers of HIV-1 disease.

Liver injury in HIV monoinfected patients: should we turn a blind eye to it?

With the advent of combined antiretroviral therapies, liver diseases have emerged as a key issue in the management of HIV infection. In addition to hepatitis co-infection, a large spectrum of liver diseases can affect the prognosis of HIV infection. Acute or progressive hepatic injuries require an accurate diagnosis for a better clinical management. Here, we provide an overview of the main liver diseases associated with HIV infection, which are not covered by the widely documented field of viral hepatitis co-infection.