Leptin, IL-6, and suPAR reflect distinct inflammatory changes associated with adiposity, lipodystrophy and low muscle mass in HIV-infected patients and controls

Brief Report: Relationship Between Adiposity and Biomarkers of Aging and Frailty Among Adults Aging With HIV

BACKGROUND

This study examined the relationships among adiposity, handgrip, physical function, inflammation (ie, senescence-associated secretory phenotype chemokines as biomarkers of aging and frailty), and sex hormones in aging people with HIV.

METHODS

This cross-sectional exploratory study included 150 people with HIV aged ≥40 years (67.3% of participants were male). Our measures included (1) body mass index and waist circumference as measures of adiposity; (2) handgrip as a measure of muscle strength; (3) short physical performance battery as a measure of physical function; (4) interleukin-6, tumor necrosis factor alpha receptor II, high sensitivity C-reactive protein, C-X-C motif chemokine 10, and C-X3-C motif chemokine ligand 1 also known as fractalkine as senescence-associated secretory phenotype chemokines; and (5) free testosterone, estradiol, sex hormone-binding globulin, and dehydroepiandrosterone as sex hormones. Quantile regression analyses were used to identify relationships among inflammatory markers and hormones with age, adiposity, handgrip, and physical function.

RESULTS

Overall, 74% (n = 111) of participants were classified as overweight or obese and 53.3% (n = 80) presented with abdominal obesity. After controlling for age and sex, body mass index was positively associated with estradiol (β = 0.043, P < 0.01), and waist circumference was positively associated with high sensitivity C-reactive protein (β = 2.151, P < 0.01). After controlling for sex, age was positively associated with C-X-C motif chemokine 10 (β = 0.024, P = 0.03) and tumor necrosis factor alpha receptor II (β = 2.205, P = 0.01). After controlling for age and sex, short physical performance battery was negatively associated with dehydroepiandrosterone (β = -0.004, P = 0.01); no statistically significant associations were observed for handgrip.

CONCLUSION

Adiposity levels and aging were associated with inflammation (ie, C-X-C motif chemokine 10, tumor necrosis factor alpha receptor II, and high sensitivity C-reactive protein) among people with HIV aged 40 years and older.

Sarcopenic obesity definitions and their associations with physical frailty in older Brazilian adults: data from the SARCOS study

Objective

To identify the obesity diagnosis with the highest association with physical frailty associated with sarcopenia EWGSOP II (sarcopenic obesity).

Subjects and methods

We performed a cross-sectional analysis of 371 community-dwelling older adults. Appendicular skeletal lean mass and total body fat (TBF) were assessed using dual-energy x-ray absorptiometry, and physical frailty was defined using Fried's criteria. The phenotypes were identified according to the presence of sarcopenia by EWGSOP II and obesity, which was diagnosed using two concepts: BMI obesity (BMI ≥ 30 kg/m²) and TBF obesity (percentage of TBF ≥ 35% for women and ≥ 25% for men). Finally, the association of each group with physical frailty was evaluated.

Results

The mean age was 78.15 ± 7.22 years. Sarcopenia EWGSOP II was diagnosed in 19.8% (n = 73), body mass index obesity was identified in 21.8% (n = 81), TBF obesity was identified in 67.7% (n = 251), and physical frailty was identified in 38.5% (n = 142). In a regression analysis for frailty, sarcopenic TBF obesity presented an odds ratio of 6.88 (95% confidence interval 2.60-18.24; p < 0.001).

Conclusion

In older Brazilian adults, sarcopenic obesity diagnosed by TBF obesity has a robust association with frailty and is independent of body mass index.

People Living With HIV, Lean Mass, and Sarcopenia: A Systematic Review and Meta-Analysis

This systematic review aims to estimate the prevalence of sarcopenia in people living with HIV (PLHIV) and to assess whether there is a difference between the muscle mass of PLHIV and people living without HIV. A systematic review of randomized controlled trials, cohort studies, cross-sectional and case-control studies was carried out. PLHIV over 18 years of age and that had their muscle mass evaluated by dual-energy X-ray absorptiometry were included. Overall, 4,376 studies were found, of which 118 had their full texts evaluated. A total of 5,532 people living with HIV and 2,986 people living without HIV were identified in 41 studies. The frequency of sarcopenia defined by low muscle mass (Baumgartner's operational definition) alone was 30.3% (95%CI 24.3%, 37.1%) and the frequency of sarcopenia defined by low muscle mass with low muscle strength (EWGSOP definition) was 4.5% (95%CI 1.3%, 13.9%), p-value = 0.0006. The standardized mean differences of muscle mass between PLHIV and controls was -0.211 units of standard deviation (95%CI -0.419, -0.003). In the meta-regression analysis muscle mass mean difference was associated with BMI, CD4, percentage of subjects on ART, and study design. PLHIV have a lower muscle mass when compared to people living without HIV. This difference appears to be attenuated by higher BMI, CD4 levels, and the percentage of subjects using ART. Furthermore, the frequencies of sarcopenia assessed by the operational definition of Baumgartner and the EWGSOP are not comparable and cannot be interchanged in PLHIV.

Poorer Muscle Quality and Quantity With ART Initiation Is Associated With Greater Inflammation and Immune Activation

BACKGROUND

We have previously shown that the initiation of antiretroviral therapy (ART) is associated with a decrease in skeletal muscle density (greater fat accumulation), suggesting that gains in lean body mass seen in many ART studies may reflect gains in low quality, fatty muscle. Here, we explore whether skeletal muscle density and area are associated with markers of inflammation and immune activation.

METHODS

ART-naïve people with HIV were randomized to raltegravir or ritonavir-boosted atazanavir or darunavir, each with tenofovir disoproxil fumarate/emtricitabine. Abdominal computed tomography scans from baseline and week 96 were reanalyzed for psoas density and area and correlations explored with inflammation [interleukin-6 (IL-6) and high-sensitivity C-reactive protein] and immune activation [soluble CD14 (sCD14), soluble CD163 (sCD163), and %CD38+HLADR+ on CD4+ or CD8+ T cells].

RESULTS

Two hundred twenty-two participants had available inflammation/immune activation markers and paired computed tomography scans. At baseline, lower psoas density (greater fat) correlated with higher IL-6 (r = -0.26, P < 0.001) and sCD163 (r -0.15, P = 0.03) and lower lean psoas area correlated with higher IL-6, high-sensitivity C-reactive protein, sCD14, sCD163, and %CD38+HLADR+ on CD4+ T cells (r = -0.30-0.13; all P ≤ 0.05). From baseline to week 96, greater percent decrease in total psoas density (more fat) correlated with greater increase in IL-6 (r = -0.14; P = 0.04); greater % decrease in lean psoas area correlated greater increases in IL-6, sCD14, sCD163, and %CD38+HLADR+ on CD8+ T cells (r = -0.15 to -0.18; all P < 0.04).

CONCLUSIONS

Greater fat infiltration within the psoas muscle (lower density) and greater loss in lean psoas muscle area were associated with higher inflammation and immune activation, which may portend important effects on muscle function and cardiometabolic risk.

Association of GDF15 With Inflammation and Physical Function During Aging and Recovery After Acute Hospitalization: A Longitudinal Study of Older Patients and Age-Matched Controls

Growth differentiation factor 15 (GDF15) is a stress-induced cytokine. Its plasma levels increase during aging and acute illness. In older Patients and age-matched Controls, we evaluated whether GDF15 levels (i) were associated with recovery after acute illness, and (ii) reflected different trajectories of aging and longitudinal changes in health measures. Fifty-two older Patients (≥65 years) were included upon admission to the emergency department (ED). At 30 days after discharge (time of matching), Patients were matched 1:1 on age and sex with Controls who had not been hospitalized within 2 years of inclusion. Both groups were followed up after 1 year. We assessed plasma levels of GDF15 and inflammatory biomarkers, frailty, nutritional status (mini nutritional assessment short-form), physical and cognitive function, and metabolic biomarkers. In Patients, elevated GDF15 levels at ED admission were associated with poorer resolution of inflammation (soluble urokinase plasminogen activator receptor [suPAR]), slowing of gait speed, and declining nutritional status between admission and 30-day follow-up. At time of matching, Patients were frailer and overall less healthy than age-matched Controls. GDF15 levels were significantly associated with participant group, on average Patients had almost 60% higher GDF15 than age-matched Controls, and this difference was partly mediated by reduced physical function. Increases in GDF15 levels between time of matching and 1-year follow-up were associated with increases in levels of interleukin-6 in Patients, and tumor necrosis factor-α and suPAR in age-matched Controls. In older adults, elevated GDF15 levels were associated with signs of accelerated aging and with poorer recovery after acute illness.

Biomarkers for length of hospital stay, changes in muscle mass, strength and physical function in older medical patients: protocol for the Copenhagen PROTECT study-a prospective cohort study

INTRODUCTION

Sarcopenia is generally used to describe the age-related loss of muscle mass and strength believed to play a major role in the pathogenesis of physical frailty and functional impairment that may occur with old age. The knowledge surrounding the prevalence and determinants of sarcopenia in older medical patients is scarce, and it is unknown whether specific biomarkers can predict physical deconditioning during hospitalisation. We hypothesise that a combination of clinical, functional and circulating biomarkers can serve as a risk stratification tool and can (i) identify older acutely ill medical patients at risk of prolonged hospital stays and (ii) predict changes in muscle mass, muscle strength and function during hospitalisation.

METHOD AND ANALYSIS

The Copenhagen PROTECT study is a prospective cohort study consisting of acutely ill older medical patients admitted to the acute medical ward at Copenhagen University Hospital, Bispebjerg and Frederiksberg, Denmark. Assessments are performed within 24 hours of admission and include blood samples, body composition, muscle strength, physical function and questionnaires. A subgroup of patients transferred to the Geriatric Department are included in a smaller geriatric cohort and have additional assessments at discharge to evaluate the relative change in circulating biomarker concentrations, body composition, muscle strength and physical function during hospitalisation. Enrolment commenced 4 November 2019, and proceeds until August 2021.

ETHICS AND DISSEMINATION

The study protocol has been approved by the local ethics committee of Copenhagen and Frederiksberg (H-19039214) and the Danish Data Protection Agency (P-2019-239) and all experimental procedures were performed in accordance with the Declaration of Helsinki. Findings from the project, regardless of the outcome, will be published in relevant peer-reviewed scientific journals in online (www.clinicaltrials.gov).

TRIAL REGISTRATION NUMBER

NCT04151108.

Resistance training with blood flow restriction: Impact on the muscle strength and body composition in people living with HIV/AIDS

The aim of the study was to compare the impact of 12-week resistance training with blood flow restriction (G_RTBFR) versus, traditional resistance training (G_TRT) and non-training on the muscle strength and body composition HIV/AIDS participants. Muscle strength was tested at baseline, and on the 6th, 21st and 36th training sessions, using maximal repetition test. Pre- and post-intervention body composition changes were measured by dual-energy X-ray absorptiometry. Resistance training was undertaken three times a week comprising bilateral elbow extension and flexion exercises, unilateral flexion and bilateral knee extension. Changes in strength and body composition (pre- and post-intervention) between groups were evaluated by mixed models of repeated measures, and by paired and unpaired comparisons, considering the Effect Size. All groups were similar at baseline for muscle strength and body composition. Post-intervention, the training groups showed similar, statistically significant increases in muscle strength (G_RTBFR=25.7-57.4%; G_TRT=24.5-52.3%) and skeletal muscle tissue (G_RTBFR=8.4%; G_TRT=8.3%). There was also a significant change in body fat (p=0.023-0.043), with significant effect sizes for strength and skeletal muscle tissue (0.41-2.27), respectively. These results suggest that both resistance training interventions promoted muscle hypertrophy, body fat reduction and positive impact on muscle strength in people living with HIV/AIDS. Resistance training with blood flow restriction proved to be an effective alternative to include patients with marked physical weakness, unable to engage in regular strength training programme.ClinicalTrials.gov identifier: NCT02783417.

Sex Differences in Circulating Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR) Levels and Adverse Outcomes in Coronary Artery Disease

Background

Women have higher circulating levels of soluble urokinase‐type plasminogen activator receptor (suPAR), and elevated suPAR is associated with cardiovascular risk. The independent association of sex with suPAR and the impact of sex on its association with cardiovascular risk are unknown.

Methods and Results

Plasma suPAR was measured using ELISA in 2 cohorts of 666 asymptomatic individuals (49 years, 65% women) and 4184 patients with coronary artery disease (63 years, 37% women). Independent association of sex with suPAR was studied using linear regression models adjusted for demographics, risk factors, and visceral adiposity in asymptomatic participants. Impact of sex on association of suPAR with all‐cause mortality was studied in patients with coronary artery disease using multivariable‐adjusted Cox models. Sex‐specific suPAR cutoffs for predicting all‐cause mortality were calculated. Asymptomatic women had 10% higher suPAR compared with men after adjusting for confounders, and visceral adiposity partly accounted for this association. Over a median follow‐up of 5.2 years, 795 deaths were recorded in patients with coronary artery disease. Log₂‐transformed suPAR was independently associated with mortality (hazard ratio per 1‐SD 1.72, 95% CI 1.60–1.85) and an interaction with sex was noted (P=0.005). Association of suPAR with mortality was slightly weaker in women (hazard ratio 1.61, 95% CI 1.41–1.83) compared with men (hazard ratio 1.83, 95% CI 1.67–2.00). However, using sex‐specific suPAR cut‐offs (4392 pg/mL for women and 3187 pg/mL for men), a similar mortality incidence was observed for both sexes (38.5% and 35.5%, respectively, P=0.3).

Conclusions

Women have 10% higher plasma suPAR levels compared with men. Elevated sex‐specific plasma suPAR levels are equally predictive of risk of adverse events in both sexes.

Sarcopenic Obesity, Insulin Resistance, and Their Implications in Cardiovascular and Metabolic Consequences

The prevalence of sarcopenic obesity is increasing worldwide, particularly amongst aging populations. Insulin resistance is the core mechanism of sarcopenic obesity and is also associated with variable cardiometabolic diseases such as cardiovascular disease, type 2 diabetes mellitus, and non-alcoholic fatty liver disease. Fat accumulation in muscle tissue promotes a proinflammatory cascade and oxidative stress, leading to mitochondrial dysfunction, impaired insulin signaling, and muscle atrophy. To compound the problem, decreased muscle mass aggravates insulin resistance. In addition, the crosstalk between myokines and adipokines leads to negative feedback, which in turn aggravates sarcopenic obesity and insulin resistance. In this review, we focus on the molecular mechanisms linking sarcopenic obesity and insulin resistance with various biological pathways. We also discuss the impact and mechanism of sarcopenic obesity and insulin resistance on cardiometabolic disease.

Histological and Molecular Adipose Tissue Changes Are Related to Metabolic Syndrome Rather Than Lipodystrophy in Human Immunodeficiency Virus-Infected Patients: A Cross-Sectional Study

Background

In human immunodeficiency virus (HIV)-infected patients on combination antiretroviral therapy (cART), lipodystrophy shares many similarities with metabolic syndrome, but only metabolic syndrome has objective classification criteria. We examined adipose tissue changes related to lipodystrophy and metabolic syndrome to clarify whether it may be acceptable to focus diagnosis on metabolic syndrome rather than lipodystrophy.

Methods

This is a cross-sectional study of 60 HIV-infected men on cART and 15 healthy men. We evaluated lipodystrophy (clinical assessment) and metabolic syndrome (JIS-2009). We compared adipocyte size, leukocyte infiltration, and gene expression in abdominal subcutaneous adipose tissue biopsies of patients with and without lipodystrophy and with and without metabolic syndrome.

Results

Lipodystrophy was only associated with increased macrophage infiltration (P = .04) and adiponectin messenger ribonucleic acid ([mRNA] P = .008), whereas metabolic syndrome was associated with larger adipocytes (P < .0001), decreased expression of genes related to adipogenesis and adipocyte function (P values between <.0001 and .08), increased leptin mRNA (P = .04), and a trend towards increased expression of inflammatory genes (P values between .08 and .6).

Conclusions

Metabolic syndrome rather than lipodystrophy was associated with major unfavorable abdominal subcutaneous adipose tissue changes. In a clinical setting, it may be more relevant to focus on metabolic syndrome diagnosis in HIV-infected patients on cART with regards to adipose tissue dysfunction and risk of cardiometabolic complications.

Abdominal obesity, sarcopenia, and osteoporosis are associated with frailty in men living with and without HIV

OBJECTIVE

The relationships between frailty and body composition in older adults with HIV infection are poorly understood. We sought to describe associations between frailty and measures of body composition among adult men with HIV and without HIV.

DESIGN/METHODS

Men with and without HIV (age 50-69 years) in the Multicenter AIDS Cohort Study (MACS) Bone Strength Substudy were included if evaluated for frailty (by Fried phenotype) and body composition [BMI, waist circumference, abdominal visceral (VAT) and subcutaneous (SAT) adipose tissue, sarcopenia, and osteopenia/osteoporosis]. All participants with HIV infection were on antiretroviral therapy. Multivariate multinomial logistic regression models were used to determine associations of frailty with body composition.

RESULTS

A total of 399 men, including 199 men with HIV and 200 men without HIV, both with median age 60 years, constituted our study population. Frailty prevalence was 16% (men with HIV) vs. 8% (men without HIV). HIV serostatus was associated with a 2.43 times higher odds of frailty (P = 0.01). Higher waist circumference, VAT, sarcopenia, and femoral neck osteoporosis were associated with increased odds of frailty (aOR 4.18, 4.45, 4.15, and 13.6, respectively, and all P < 0.05); BMI and SAT were not. None of these measures presented a differential association with frailty by HIV serostatus (all P > 0.20).

CONCLUSION

Higher abdominal obesity and sarcopenia were associated with frailty among men with and without HIV. Assessment of these body composition parameters may help detect frailty in the clinical setting.

Inflammation and post-operative recovery in patients undergoing total knee arthroplasty-secondary analysis of a randomized controlled trial

OBJECTIVE

Reduced function persists for many patients after total knee arthroplasty (TKA). Inflammation is part of osteoarthritis' pathophysiology, and surgery induces a marked inflammatory response. We therefore wanted to explore the role of inflammation in long-term recovery after TKA, and thus conducted this secondary analysis of our randomized controlled trial (RCT) of physical rehabilitation ± progressive strength training (PST). We aimed to investigate whether (1) inflammation is associated with functional performance, knee-extension strength, and knee pain before TKA; (2) PST affects inflammation, and the inflammatory state over time; (3) baseline or surgery-induced inflammation modifies the effect of rehabilitation ± PST on change in 6-min walk test (Δ6MWT); and (4) baseline or surgery-induced inflammation is associated with Δ6MWT following TKA.

DESIGN

In the primary trial report's per-protocol analysis, 72/82 patients were included. Sixty had ≥1 blood sample before and after TKA, and were included in this secondary analysis. Inflammation was measured by interferon γ-inducible protein (IP)-10, soluble urokinase plasminogen activator receptor (suPAR), interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α at baseline; day 1, week 4, 8, and 26 after TKA.

RESULTS

At baseline, suPAR (P = 006) was negatively associated with 6MWT. Neither baseline nor surgery-induced inflammation modified the response to rehabilitation ± PST. Only surgery-induced IL-10 was associated with Δ6MWT_{26 weeks-baseline} (P = 0.001), also adjusted for 6MWT_baseline, age, sex and body mass index (BMI).

CONCLUSION

In this secondary analysis, only increased surgery-induced IL-10 response was associated with decreased long-term functional performance after TKA. The importance of controlling the surgery-induced immune response remains to be investigated further.

TRIAL IDENTIFICATION

NCT01351831.

Correlation of Leptin, Adiponectin, and Resistin Levels in Different Types of Lipodystrophy in HIV/AIDS Patients

BACKGROUND

Leptin, adiponectin, and resistin may play an important role in the development of lipodystrophy (LD) in HIV/AIDS patients. The aim of this study was to correlate levels of leptin, adiponectin, and resistin between HIV/AIDS patients with LD and without lipodystrophy (non-LD), as well as between subgroups of LD [lipoatrophy (LA), lipohypertrophy (LH), and mixed fat redistribution (MFR)] and non-LD patients.

METHODS

Cross-sectional study of 66 HIV/AIDS patients. Serum levels of leptin, adiponectin, and resistin were measured. The associations between adipocytokine levels and metabolic variables were estimated by Spearman correlation. Analysis of covariance with bootstrapping method was used to examine the relationship between adiponectin and leptin and lipodystrophy categories.

RESULTS

The LD was observed in 29 (44%) patients, while 15 (52%) of them had LA, 4 (14%) had LH, and 10 (34%) patients had MFR. No significant differences regarding leptin, adiponectin, and resistin levels, between LD and non-LD patients, were observed. LH patients had significantly higher levels of leptin and adiponectin in comparison with non-LD patients (P = 0.039, P = 0.011, respectively). Within the LD group, LA patients had significantly lower levels of leptin (LA vs. LH, P = 0.020; LA vs. MFR, P = 0.027), while LH patients had significantly higher levels of adiponectin (LH vs. LA, P = 0.027; LH vs. MFR, P = 0.028). Correlation of adiponectin with LD remains significant in the LH subgroup after adjustment for age, body mass index, cystatin-C, plasminogen activator inhibitor-1 (PAI-1), and interferon gamma (IFN-γ) (P = 0.001).

CONCLUSIONS

Adiponectin and leptin levels differ significantly between LH patients and non-LD patients, as well as between the LD subgroups. Adiponectin may be a more useful marker of LD in HIV/AIDS patients.

Does persistent HIV replication explain continued lymphoma incidence in the era of effective antiretroviral therapy?

Non-Hodgkin lymphomas are highly increased in incidence in individuals infected with HIV, and this continues to be the case in spite of highly effective combined antiretroviral therapy (cART). New evidence has demonstrated that while successful virtual recovery of CD4 counts and elimination of HIV from peripheral blood can be achieved with cART, viral replication can still occur in lymphoid tissues. In addition, recent studies have suggested that adipose tissue provides an additional reservoir for HIV-infected macrophages and T lymphocytes even in the context of successful cART therapy. In this review article, we discuss possible mechanisms leading to the development of lymphoma in the cART era.

Obesity in patients with HIV infection: epidemiology, consequences and treatment options

Even though wasting used to characterize patients with HIV infection prior to the antiretroviral therapy (ART) era, obesity is becoming increasingly prevalent in this population. Areas covered: In the present review, we discuss the epidemiology, consequences and treatment options for obesity in patients with HIV infection. Expert commentary: Obesity exerts a multitude of detrimental cardiometabolic effects and appears to contribute to the increasing cardiovascular mortality of this population. However, there are very limited data on the optimal management of obesity in patients with HIV infection. Given the potential for interactions between antiobesity agents and ART that might compromise viral control, lifestyle changes should represent the cornerstone for the prevention and management of obesity in HIV infection.

Low-dose growth hormone therapy reduces inflammation in HIV-infected patients: a randomized placebo-controlled study

BACKGROUND

Combination antiretroviral therapy (cART) has drastically increased the life expectancy of HIV-infected patients. However, HIV-infected patients exhibit increased inflammation and 33-58% exhibit a characteristic fat re-distribution termed HIV-associated lipodystrophy syndrome (HALS). Recombinant human growth hormone (rhGH) has been tested as treatment of HALS. Low-dose rhGH therapy improves thymopoiesis and fat distribution in HIV-infected patients and appears to be well tolerated. However, since high-dose rhGH is associated with adverse events related to inflammation, we wanted to investigate the impact of low-dose rhGH therapy on inflammation in HIV-infected patients.

METHODS

Forty-six cART-treated HIV-infected men were included in the HIV-GH low-dose (HIGH/Low) study: a randomized, placebo-controlled, double-blinded trial. Subjects were randomized 3:2 to 0.7 mg/day rhGH, or placebo for 40 weeks. rhGH was self-administered between 1 pm and 3 pm. The primary outcome of this substudy was changes in inflammation measured by plasma C-reactive protein (CRP) and soluble urokinase plasminogen activator receptor (suPAR).

RESULTS

Both CRP (-66%, p = 0.002) and suPAR (-9.7%, p = 0.06) decreased in the rhGH group compared to placebo; however, only CRP decreased significantly. The effect of rhGH on inflammation was not mediated through rhGH-induced changes in insulin-like growth factor 1, body composition, or immune parameters.

CONCLUSION

Daily 0.7 mg rhGH treatment for 40 weeks, administered at nadir endogenous GH secretion, significantly reduced CRP. The effect does not appear to be mediated by other factors. Our findings suggest that low-dose rhGH treatment may minimize long-term risks associated with high-dose rhGH therapy.

Current topics in HIV pathogenesis, part 2: Inflammation drives a Warburg-like effect on the metabolism of HIV-infected subjects

HIV-1 infection leads to a depletion of CD4 T-cells associated with a persistent immune inflammation and changes in cellular metabolism. Most effort of managing HIV infection with combination of antiretroviral therapies (ART) has been focused on CD4 T-cell recovery, while control of persistent immune inflammation and metabolism were relatively underappreciated in the past. Recent discoveries on the interplay between innate immunity, inflammation (especially the inflammasome) and metabolic changes in the context of cancer and autoimmunity provide an emerging field for chronic viral infections including HIV-1. In a previous review, we described the deregulated metabolism contributing to immune dysfunctions such as alteration of memory T-cell responses, mucosal protection, and dendritic cell-related antigen presentation. Here, we summarize the latest knowledge on the detrimental influence of long-lasting inflammation and inflammasome activation induced by HIV-1, gut dysbiosis, and bacterial translocation, on metabolism during the course of viral infection. We also report on the inability of ART to fully counteract inflammation, resulting in partial metabolic improvement and leading to an insufficient decrease in the risk of non-AIDS events. Further advances in our understanding of the relationship between inflammation, altered metabolism, and long-term ART is warranted. Additionally, there is a critical need for developing new strategies to regulate the pro-inflammatory signals to enhance cellular metabolism and immune functions in order to improve the quality of life of individuals living with HIV-1.

Immunosenescence of the CD8(+) T cell compartment is associated with HIV-infection, but only weakly reflects age-related processes of adipose tissue, metabolism, and muscle in antiretroviral therapy-treated HIV-infected patients and controls

Background

Despite effective antiretroviral therapy (ART), HIV-infected patients exhibit systemic inflammation, early onset of age-related diseases, and features of immunosenescence. The role of inflammation in the development of age-related diseases is widely recognized. However, the role of immunosenescence is not well established. Studying immunosenescence in HIV-infection could give insight into its role in ageing processes. In this cross-sectional study, we aimed to investigate whether ART-treated HIV-infected patients exhibit immunosenescence; and whether immunosenescence is associated with age-related processes of inflammation, metabolism, adipose tissue, and muscle. T cell immunosenescence and exhaustion were assessed by flow cytometry analysis of CD8⁺ cells from 43 ART-treated HIV-infected patients (HIV⁺) and ten Controls using markers of differentiation: CD27/CD28; maturation: CD27/CD45RA; senescence: killer cell lectin-like receptor G1 (KLRG1); and exhaustion: programmed death-1 (PD-1). Relationships between CD8⁺ T cell immunosenescence, exhaustion, and age-related processes were assessed using linear regressions.

Results

HIV-infection was strongly associated with more highly differentiated and mature CD8⁺ T cell phenotypes. PD-1 and KLRG1 expression did not differ between HIV⁺ and Controls, but depended on differentiation and maturation stages of the cells. CD8⁺ T cell maturation was associated with age. KLRG1 expression was associated with age, metabolic syndrome, visceral adipose tissue, and high muscle mass. PD-1 expression was not associated with age-related parameters.

Conclusions

HIV-infection strongly affected CD8⁺ T cell differentiation and maturation, whereas age-related processes were only weakly associated with immune parameters. Our findings suggest that, in contrast to inflammation, immunosenescence appears to be highly dependent on HIV-infection and is only to a small extent associated with age-related parameters in well-treated HIV-infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-015-0136-6) contains supplementary material, which is available to authorized users.