Premature expression of a muscle fibrosis axis in chronic HIV infection

Maladaptive Immune Activation in Age-Related Decline of Muscle Function

Age-related changes in immune competency and inflammation play a role in the decline of physical function. In this review of the conference on Function-Promoting Therapies held in March 2022, we discuss the biology of aging and geroscience with an emphasis on decline in physical function and the role of age-related changes in immune competence and inflammation. More recent studies in skeletal muscle and aging highlighting a crosstalk between skeletal muscle, neuromuscular feedback, and immune cell subsets are also discussed. The value of strategies targeting specific pathways that affect skeletal muscle and more systems-wide approaches that provide benefits in muscle homeostasis with aging are underscored. Goals in clinical trial design and the need for incorporating differences in life history when interpreting results from these intervention strategies are important. Where applicable, references are made to papers presented at the conference. We conclude by underscoring the need to incorporate age-related immune competency and inflammation when interpreting results from interventions that target specific pathways predicted to promote skeletal muscle function and tissue homeostasis.

Antiretroviral protease inhibitors induce features of cellular senescence that are reversible upon drug removal

Antiretroviral drugs have dramatically improved the prognosis of HIV-infected patients, with strikingly reduced morbidity and mortality. However, long-term use can be associated with signs of premature aging. Highly active antiretroviral therapy generally comprises two nucleoside reverse transcriptase inhibitors (NRTIs), with one of three additional antiretroviral drug classes, including protease inhibitors (PIs). One commonality between mitochondrial dysfunction (induced by NRTIs) and defects in lamin A (induced by PIs) is they can cause or accelerate cellular senescence, a state of essentially irreversible growth arrest, and the secretion of many bioactive molecules collectively known as the senescence-associated secretory phenotype (SASP). We hypothesized that senescent cells increase following treatment with certain HIV therapies. We compared the effects of two distinct HIV PIs: ritonavir-boosted atazanavir (ATV/r) and ritonavir-boosted darunavir (DRN/r), used in combination treatments for HIV infection. Upon ATV/r, but not DRN/r, treatment, cells arrested growth, displayed multiple features of senescence, and expressed significantly upregulated levels of many SASP factors. Furthermore, mice receiving sustained ATV/r treatment showed an increase in senescent cells and age-related decline in physiological function. However, removing treatment reversed the features of senescence observed in vivo and cell culture. Given how these features disappeared with drug removal, certain features of senescence may not be prognostic as defined by an irreversible growth arrest. Importantly, for patients that are treated or have been treated with ATV/r, our data suggest that switching to another PI that does not promote premature aging conditions (DRN/r) may improve the associated age-related complications.

Single nuclei profiling identifies cell specific markers of skeletal muscle aging, frailty, and senescence

Aging is accompanied by a loss of muscle mass and function, termed sarcopenia, which causes numerous morbidities and economic burdens in human populations. Mechanisms implicated in age-related sarcopenia or frailty include inflammation, muscle stem cell depletion, mitochondrial dysfunction, and loss of motor neurons, but whether there are key drivers of sarcopenia are not yet known. To gain deeper insights into age-related muscle loss, we performed transcriptome profiling on lower limb muscle biopsies from 72 young, elderly, and frail human subjects using bulk RNA-seq (N = 72) and single-nuclei RNA-seq (N = 17). This combined approach revealed changes in gene expression that occur with age and frailty in multiple cell types comprising mature skeletal muscle. Notably, we found increased expression of the genes MYH8 and PDK4, and decreased expression of the gene IGFN1, in aged muscle. We validated several key genes changes in fixed human muscle tissue using digital spatial profiling. We also identified a small population of nuclei that express CDKN1A, present only in aged samples, consistent with p21cip1-driven senescence in this subpopulation. Overall, our findings identify unique cellular subpopulations in aged and sarcopenic skeletal muscle, which will facilitate the development of new therapeutic strategies to combat age-related frailty.

Body composition, physical fitness and physical activity in Mozambican children and adolescents living with HIV

INTRODUCTION

As a result of the effectiveness of antiretroviral drugs (ART), HIV/AIDS has become a chronic disease, which has enabled children living with HIV to reach adolescence and adulthood. However, the long exposure to both the disease and ART has caused undesirable effects that compromise the physiological functioning and the quality of life of the subjects.

OBJECTIVE

To determine the body composition, physical fitness and habitual physical activity of children and adolescents living with HIV on ART.

METHODS

A total of 79 subjects of both genders aged 8-14 years, living with HIV in ART, selected by convenience participated in the study. The subjects underwent anthropometric assessment, physical fitness assessment and physical activity assessment.

RESULTS

Relative to reference norms, the values of the anthropometric indicators fell below 50th percentile (height/age = 92.4%; BMI/age 72.2%; sum of skinfolds = 51.9%; arm circumference = 63.3%). The prevalence of "low height/age" and "low weight/age" was 34.9% and 9.3%, respectively for boys, and 27.9% and 11.1%, respectively for girls. With the exception of trunk flexibility (12.3%), most subjects were considered unfit in the physical fitness tests (abdominal resistance = 76.4%; handgrip strength = 75.4%; lower limb power = 66.4%). The percentage of subjects with insufficient physical activity was 45.5% for boys and 77.8% for girls. The values for all variables were consistently and significantly lower when compared with studies done in Mozambicans boys and girls without HIV+ from both urban and rural areas.

CONCLUSION

The subjects participants in the study living with HIV and undergoing ART had impaired growth, low physical fitness and low levels of habitual physical activity in relation to the reference values of their peers without HIV, which compromised their physiological functioning and their quality of life.

Biological ageing with HIV infection: evaluating the geroscience hypothesis

Although people with HIV are living longer, as they age they remain disproportionately burdened with multimorbidity that is exacerbated in resource-poor settings. The geroscience hypothesis postulates that a discrete set of between five and ten hallmarks of biological ageing drive multimorbidity, but these processes have not been systematically examined in the context of people with HIV. We examine four major hallmarks of ageing (macromolecular damage, senescence, inflammation, and stem-cell dysfunction) as gerodrivers in the context of people with HIV. As a counterbalance, we introduce healthy ageing, physiological reserve, intrinsic capacity, and resilience as promoters of geroprotection that counteract gerodrivers. We discuss emerging geroscience-based diagnostic biomarkers and therapeutic strategies, and provide examples based on recent advances in cellular senescence, and other, non-pharmacological approaches. Finally, we present a conceptual model of biological ageing in the general population and in people with HIV that integrates gerodrivers and geroprotectors as modulators of homoeostatic reserves and organ function over the lifecourse.

Differences in Muscle Quantity and Quality by HIV Serostatus and Sex

OBJECTIVE

People with HIV (PWH) experience greater declines in both muscle function and muscle mass with aging. Whether changes in muscle quality and quantity with aging differ between men and women with HIV and the implications on muscle function are not established.

DESIGN

In coordinated substudies of the Multicenter AIDS Cohort Study and Women's Interagency HIV Study, participants completed physical function and falls assessments; total trunk/thigh density, inversely related to fatty infiltration, and area were quantified from computed tomography (CT) scans.

METHODS

Generalized linear models were used to explore variables affecting density/area, and associations between area/density and physical function and falls.

RESULTS

CT scans were available on 387 men (198 PWH) and 184 women (118 PWH). HIV serostatus was associated with greater lateralis, paraspinal, and hamstring area, but lower psoas area and density. Older age and female sex were associated with smaller trunk muscle area and lower density. Both lower muscle area and muscle density were associated with several measures of impaired physical function. The odds of falling were lower with greater hamstring density, but not associated with other measurers of muscle area or density.

CONCLUSIONS

In summary, older adults with HIV appear to have smaller and less dense (fattier) psoas, a key component in truncal stability and hip flexion that could have implications on physical function. The longitudinal associations of muscle area and density with physical function require careful investigation, with a particular focus on characteristics and interventions that can preserve muscle area, density, and function over time.

Physical Function Impairment and Frailty in Middle-Aged People Living With Human Immunodeficiency Virus in the REPRIEVE Trial Ancillary Study PREPARE

BACKGROUND

People with human immunodeficiency virus (PWH) are at risk for accelerated development of physical function impairment and frailty; both associated with increased risk of falls, hospitalizations, and death. Identifying factors associated with physical function impairment and frailty can help target interventions.

METHODS

The REPRIEVE trial enrolled participants 40-75 years of age, receiving stable antiretroviral therapy with CD4+ T-cell count >100 cells/mm3, and with low to moderate cardiovascular disease risk. We conducted a cross-sectional analysis of those concurrently enrolled in the ancillary study PREPARE at enrollment.

RESULTS

Among the 266 participants, the median age was 51 years; 81% were male, and 45% were black, and 28% had hypertension. Body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) was 25 to <30 in 38% and ≥30 in 30%, 33% had a high waist circumference, 89% were physically inactive, 37% (95% confidence interval, 31%, 43%) had physical function impairment (Short Physical Performance Battery score ≤10), and 6% (4%, 9%) were frail and 42% prefrail. In the adjusted analyses, older age, black race, greater BMI, and physical inactivity were associated with physical function impairment; depression and hypertension were associated with frailty or prefrailty.

CONCLUSIONS

Physical function impairment was common among middle-aged PWH; greater BMI and physical inactivity are important modifiable factors that may prevent further decline in physical function with aging.

CLINICAL TRIALS REGISTRATION

NCT02344290.

Gene Expression: the Key to Understanding HIV-1 Infection?

Gene expression profiling of the host response to HIV infection has promised to fill the gaps in our knowledge and provide new insights toward vaccine and cure. However, despite 20 years of research, the biggest questions remained unanswered. A literature review identified 62 studies examining gene expression dysregulation in samples from individuals living with HIV. Changes in gene expression were dependent on cell/tissue type, stage of infection, viremia, and treatment status. Some cell types, notably CD4+ T cells, exhibit upregulation of cell cycle, interferon-related, and apoptosis genes consistent with depletion. Others, including CD8+ T cells and natural killer cells, exhibit perturbed function in the absence of direct infection with HIV. Dysregulation is greatest during acute infection. Differences in study design and data reporting limit comparability of existing research and do not as yet provide a coherent overview of gene expression in HIV. This review outlines the extraordinarily complex host response to HIV and offers recommendations to realize the full potential of HIV host transcriptomics.

Atypical Skeletal Muscle Profiles in Human Immunodeficiency Virus-Infected Asymptomatic Middle-Aged Adults

Background

Human immunodeficiency virus (HIV)-infected individuals are at increased risk of age-associated functional impairment, even with effective antiretroviral therapy (ART). A concurrent characterization of skeletal muscle, physical function, and immune phenotype in aviremic middle-aged HIV-infected adults represents a knowledge gap in prognostic biomarker discovery.

Methods

We undertook a prospective observational study of 170 middle-aged, HIV-infected ambulatory men and women with CD4+ T-cell counts of at least 350/µL and undetectable plasma viremia while on effective ART, and uninfected control participants. We measured biomarkers for inflammation and immune activation, fatigue, the Veterans Aging Cohort Study mortality index, and physical function. A subset also received a skeletal muscle biopsy and computed tomography scan.

Results

Compared to the uninfected participants, HIV-infected participants displayed increased immune activation (P < .001), inflammation (P = .001), and fatigue (P = .010), and in a regression model adjusting for age and sex displayed deficits in stair-climb power (P < .001), gait speed (P = .036), and predicted metabolic equivalents (P = .019). Skeletal muscle displayed reduced nuclear peroxisome proliferator-activated receptor-γ coactivator 1α-positive myonuclei (P = .006), and increased internalized myonuclei (P < .001) that correlated with immune activation (P = .003) and leukocyte infiltration (P < .001). Internalized myonuclei improved a model for HIV discrimination, increasing the C-statistic from 0.84 to 0.90.

Conclusions

Asymptomatic HIV-infected middle-aged adults display atypical skeletal muscle profiles, subclinical deficits in physical function, and persistent inflammation and immune activation. Identifying biomarker profiles for muscle dysregulation and risk for future functional decline in the HIV-infected population will be key to developing and monitoring preventive interventions.

Clinical Trials Registration

NCT03011957.

Objective impairments of gait and balance in adults living with HIV-1 infection: a systematic review and meta-analysis of observational studies

BACKGROUND

Gait and balance deficits are reported in adults with HIV infection and are associated with reduced quality of life. Current research suggests an increased fall-incidence in this population, with fall rates among middle-aged adults with HIV approximating that in seronegative elderly populations. Gait and postural balance rely on a complex interaction of the motor system, sensory control, and cognitive function. However, due to disease progression and complications related to ongoing inflammation, these systems may be compromised in people with HIV. Consequently, locomotor impairments may result that can contribute to higher-than-expected fall rates. The aim of this review was to synthesize the evidence regarding objective gait and balance impairments in adults with HIV, and to emphasize those which could contribute to increased fall risk.

METHODS

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search of published observational studies was conducted in March 2016. Methodological quality was assessed using the NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Narrative synthesis of gait and balance outcomes was performed, and meta-analyses where possible.

RESULTS

Seventeen studies were included, with fair to low methodological quality. All studies used clinical tests for gait-assessment. Gait outcomes assessed were speed, initiation-time and cadence. No studies assessed kinetics or kinematics. Balance was assessed using both instrumented and clinical tests. Outcomes were mainly related to center of pressure, postural reflex latencies, and timed clinical tests. There is some agreement that adults with HIV walk slower and have increased center of pressure excursions and -long loop postural reflex latencies, particularly under challenging conditions.

CONCLUSIONS

Gait and balance impairments exist in people with HIV, resembling fall-associated parameters in the elderly. Impairments are more pronounced during challenging conditions, might be associated with disease severity, are not influenced by antiretroviral therapy, and might not be associated with peripheral neuropathy. Results should be interpreted cautiously due to overall poor methodological quality and heterogeneity. Locomotor impairments in adults with HIV are currently insufficiently quantified. Future research involving more methodological uniformity is warranted to better understand such impairments and to inform clinical decision-making, including fall-prevention strategies, in this population.

Disease drivers of aging

It has long been known that aging, at both the cellular and organismal levels, contributes to the development and progression of the pathology of many chronic diseases. However, much less research has examined the inverse relationship-the contribution of chronic diseases and their treatments to the progression of aging-related phenotypes. Here, we discuss the impact of three chronic diseases (cancer, HIV/AIDS, and diabetes) and their treatments on aging, putative mechanisms by which these effects are mediated, and the open questions and future research directions required to understand the relationships between these diseases and aging.

Muscle power in children, youth and young adults who acquired HIV perinatally

OBJECTIVES

To compare muscle power between youth who acquired HIV perinatally and HIV unexposed uninfected (HUU) youth.

METHODS

We assessed muscle power (relative to body mass, P_max/mass), muscle force normalized to body weight (F_max/BW), force efficiency, jump height (H_max) and velocity (V_max) during a single two-legged jump with hands on waist on a force platform (Leonardo) in HIV+ youth (n=35, 9-21 y). Thirty-three and 22 participants returned at 12- and 24-months, respectively. We compared age- and sex-specific z-scores in the HIV+ youth to those in HUU controls (n=716, 9-21 y) adjusting for height and muscle cross-sectional area (MCSA, by pQCT).

RESULTS

At baseline, z-scores for Pmax/mass, F_max/BW and V_max were less than 1 standard deviation lower than HUU after adjusting for height and MCSA (p⟨0.05). P_max/mass z-score was negatively associated with level of immunosuppression (p=0.013), but this relationship was not significant after adjusting for height and MCSA (p=0.07). Z-scores for all mechanography outcomes remained stable over time in HIV+ youth.

CONCLUSION

Small deficits in muscle power were apparent in children and youth who acquired HIV perinatally, and the trajectory of muscle power did not change over two years. Further study is needed to identify effective strategies to improve dynamic muscle function in this population.

Geriatric syndromes: new frontiers in HIV and sarcopenia

: HIV infection, in many circumstances, can now be managed as a chronic disease due to the marked increase in life expectancy since the introduction of combination antiretroviral therapy (ART). As the patients who first had access to combination ART age into their 50s and 60s, the effects of chronic HIV infection on health have become an important research focus in HIV infection. People living with HIV appear to exhibit an earlier occurrence of some aging-related conditions compared to people without HIV, in part due to higher rates of comorbidities, high-risk behaviors (e.g. smoking, substance use), chronic immune activation, inflammation, and ART-specific factors. Some studies have even suggested an earlier-than-expected appearance of the 'geriatric syndromes,' which are complex medical syndromes of older adults that are associated with morbidity and mortality. The geriatric syndromes include a wide variety of disease processes ranging from incontinence and dementia to impairments in physical function. This review will focus on one geriatric syndrome, sarcopenia, in older HIV-infected populations, and its relation to other aging syndromes, including frailty and falls. The contribution of HIV itself, ART exposure, and specific comorbidities, and the importance of early recognition and prevention of these aging syndromes will be highlighted.

Administration of an activin receptor IIB ligand trap protects male juvenile rhesus macaques from simian immunodeficiency virus-associated bone loss

HIV-infected individuals are at an increased risk of osteoporosis despite effective viral suppression. Observations that myostatin null mice have increased bone mass led us to hypothesize that simian immunodeficiency virus (SIV)-associated bone loss may be attenuated by blocking myostatin/TGFβ signaling. In this proof-of-concept study, pair-housed juvenile male rhesus macaques were inoculated with SIVmac239. Four weeks later, animals were treated with vehicle or Fc-conjugated soluble activin receptor IIB (ActR2B·Fc, iv. 10mg∗kg^-1∗week^-1) - an antagonist of myostatin and related members of TGFβ superfamily. Limb and trunk bone mineral content (BMC) and density (BMD) using dual-energy X-Ray absorptiometry, circulating markers of bone growth and turnover, and serum testosterone levels were measured at baseline and during the 12-week intervention period. The increase in BMC was significantly greater in the ActRIIB.Fc-treated group (+8g) than in the placebo group (-4g) (p<0.05). BMD also increased significantly more in the ActRIIB.Fc-treated macaques (+0.03g/cm²) than in the placebo-treated animals (+0g/cm²) (p<0.005). Serum osteocalcin was about two-fold higher in the ActRIIB.Fc-treated group than in the placebo group (p<0.05), but serum C-terminal telopeptide and testosterone levels did not differ significantly between groups. The expression levels of TNFalpha (p<0.05), GADD45 (p<0.005), and sclerostin (p<0.038) in the bone-marrow were significantly lower in the ActRIIB.Fc-treated group than in the placebo group.

CONCLUSION

The administration of ActRIIB.FC in SIV-infected juvenile macaques significantly increases BMC and BMD in association with reduced expression levels of markers of bone marrow inflammation.

Effects of fitness training on physical fitness parameters and quality of life in human immunodeficiency virus-positive Indian females

PURPOSE

Highly active antiretroviral therapy has significantly extended survival of human immunodeficiency virus (HIV) infected patients. These drugs suppress replication of HIV but at the same time, have many physical and mental side effects which may affect daily activities of the patients. The present study assessed if moderate intensity exercise program helped in enhancing the physical fitness and quality of life (QoL) in HIV positive females which may reduce the comorbidities associated with the disease and medications.

AIM AND OBJECTIVES

The aim of this study is to study the effects of moderate intensity physical training on physical fitness parameters and QoL in HIV positive females.

METHODOLOGY

Post IEC approval, a randomized control, single-blinded, parallel group trial was conducted on 55 females (20 experimental HIV, 20 control HIV, 15 control normal) matching the selection criteria. Post informed consent, their muscular endurance, flexibility, aerobic capacity, and QoL was assessed. Moderate intensity physical exercises were given to experimental HIV and control normal 5 days/week for 8 weeks and subjects were reassessed for above parameters. Intragroup analysis was performed using paired t-test while inter-group was by one-way ANOVA with alpha set at ≤0.05.

RESULTS

Moderate-intensity exercises improved muscular endurance (P < 0.05), flexibility (P < 0.05), and aerobic capacity (P < 0.05)in experimental HIV and control normal group as compared to control HIV group. QoL in experimental HIV showed improvement in all the domains.

CONCLUSION

Moderate-intensity exercises help improve the physical fitness as well as enhance the QoL in HIV positive females.

Hydroxyproline-containing collagen peptide derived from the skin of the Alaska pollack inhibits HIV-1 infection

The human immunodeficiency virus (HIV) is a lentivirus that results in acquired immunodeficiency syndrome (AIDS). HIV treatment involving chemical therapeutic agents has improved the quality of life of HIV/AIDS patients. The present study demonstrates that a hydroxyproline-containing marine collagen peptide (APHCP) derived from Alaska pollack inhibits HIV‑1 infection in the MT-4 human T cell‑line. APHCP inhibited HIV-1IIIB-induced cell lysis, syncytia formation, reverse transcriptase activity and viral p24 production at non‑cytotoxic concentrations; however, APHCP did not inhibit HIV‑2ROD infection in MT‑4 cells. This suggests that the anti‑HIV activity of APHCP is specific to HIV‑1. In addition, substitution of hydroxyproline residues in APHCP with prolines impaired its anti‑HIV‑1 activity, suggesting that the hydroxyl group of hydroxyprolines is required for the anti‑HIV‑1 activity of APHCP. These results suggested that the marine peptide APHCP may be a novel drug candidate in the development of next‑generation therapeutic agents for the treatment of HIV/AIDS.

The Effects of Dietary Omega-3s on Muscle Composition and Quality in Older Adults

This review will focus on findings from the few studies performed to date in humans to examine changes in muscle protein turnover, lean or muscle mass and physical function following fish oil-derived omega-3 fatty acid treatment. Although considerable gaps in our current knowledge exist, hypertrophic responses (e.g., improvements in the rate of muscle protein synthesis and mTOR signaling during increased amino acid availability and an increase in muscle volume) have been reported in older adults following prolonged (8 to 24 weeks) of omega-3 fatty acid supplementation. There is also accumulating evidence that increased omega-3 fatty acid levels in red blood cells are positively related to strength and measures of physical function. As a result, increased omega-3 fatty acid consumption may prove to be a promising low-cost dietary approach to attenuate or prevent aging associated declines in muscle mass and function.

Early Regulation of Profibrotic Genes in Primary Human Cardiac Myocytes by Trypanosoma cruzi

The molecular mechanisms of Trypanosoma cruzi induced cardiac fibrosis remains to be elucidated. Primary human cardiomyoctes (PHCM) exposed to invasive T. cruzi trypomastigotes were used for transcriptome profiling and downstream bioinformatic analysis to determine fibrotic-associated genes regulated early during infection process (0 to 120 minutes). The identification of early molecular host responses to T. cruzi infection can be exploited to delineate important molecular signatures that can be used for the classification of Chagasic patients at risk of developing heart disease. Our results show distinct gene network architecture with multiple gene networks modulated by the parasite with an incline towards progression to a fibrogenic phenotype. Early during infection, T. cruzi significantly upregulated transcription factors including activator protein 1 (AP1) transcription factor network components (including FOSB, FOS and JUNB), early growth response proteins 1 and 3 (EGR1, EGR3), and cytokines/chemokines (IL5, IL6, IL13, CCL11), which have all been implicated in the onset of fibrosis. The changes in our selected genes of interest did not all start at the same time point. The transcriptome microarray data, validated by quantitative Real-Time PCR, was also confirmed by immunoblotting and customized Enzyme Linked Immunosorbent Assays (ELISA) array showing significant increases in the protein expression levels of fibrogenic EGR1, SNAI1 and IL 6. Furthermore, phosphorylated SMAD2/3 which induces a fibrogenic phenotype is also upregulated accompanied by an increased nuclear translocation of JunB. Pathway analysis of the validated genes and phospho-proteins regulated by the parasite provides the very early fibrotic interactome operating when T. cruzi comes in contact with PHCM. The interactome architecture shows that the parasite induces both TGF-β dependent and independent fibrotic pathways, providing an early molecular foundation for Chagasic cardiomyopathy. Examining the very early molecular events of T. cruzi cellular infection may provide disease biomarkers which will aid clinicians in patient assessment and identification of patient subpopulation at risk of developing Chagasic cardiomyopathy.

The effects of an ActRIIb receptor Fc fusion protein ligand trap in juvenile simian immunodeficiency virus-infected rhesus macaques

There are no approved therapies for muscle wasting in children infected with human immunodeficiency virus (HIV), which portends poor disease outcomes. To determine whether a soluble ActRIIb receptor Fc fusion protein (ActRIIB.Fc), a ligand trap for TGF-β/activin family members including myostatin, can prevent or restore loss of lean body mass and body weight in simian immunodeficiency virus (SIV)-infected juvenile rhesus macaques (Macaca mulatta). Fourteen pair-housed, juvenile male rhesus macaques were inoculated with SIVmac239 and, 4 wk postinoculation (WPI) treated with intramuscular injections of 10 mg ⋅ kg(-1) ⋅ wk(-1) ActRIIB.Fc or saline placebo. Body weight, lean body mass, SIV titers, and somatometric measurements were assessed monthly for 16 wk. Age-matched SIV-infected rhesus macaques were injected with saline. Intervention groups did not differ at baseline. Gains in lean mass were significantly greater in the ActRIIB.Fc group than in the placebo group (P < 0.001). Administration of ActRIIB.Fc was associated with greater gains in body weight (P = 0.01) and upper arm circumference than placebo. Serum CD4(+) T-lymphocyte counts and SIV copy numbers did not differ between groups. Administration of ActRIIB.Fc was associated with higher muscle expression of myostatin than placebo. ActRIIB.Fc effectively blocked and reversed loss of body weight, lean mass, and fat mass in juvenile SIV-infected rhesus macaques.

It is not just muscle mass: a review of muscle quality, composition and metabolism during ageing as determinants of muscle function and mobility in later life

Worldwide estimates predict 2 billion people will be aged over 65 years by 2050. A major current challenge is maintaining mobility and quality of life into old age. Impaired mobility is often a precursor of functional decline, disability and loss of independence. Sarcopenia which represents the age-related decline in muscle mass is a well-established factor associated with mobility limitations in older adults. However, there is now evidence that not only changes in muscle mass but other factors underpinning muscle quality including composition, metabolism, aerobic capacity, insulin resistance, fat infiltration, fibrosis and neural activation may also play a role in the decline in muscle function and impaired mobility associated with ageing. Importantly, changes in muscle quality may precede loss of muscle mass and therefore provide new opportunities for the assessment of muscle quality particularly in middle-aged adults who could benefit from interventions to improve muscle function. This review will discuss the accumulating evidence that in addition to muscle mass, factors underpinning muscle quality influence muscle function and mobility with age. Further development of tools to assess muscle quality in community settings is needed. Preventative diet, exercise or treatment interventions particularly in middle-aged adults at the low end of the spectrum of muscle function may help preserve mobility in later years and improve healthspan.

Physical activity and capacity at initiation of antiretroviral treatment in HIV patients in Ethiopia

SUMMARY We described levels of habitual physical activity and physical capacity in HIV patients initiating antiretroviral treatment in Ethiopia and assessed the role of HIV and nutritional indicators on these outcomes. Physical activity energy expenditure (PAEE) and activity levels were measured with combined heart rate and movement sensors. Physical capacity was assessed by grip strength, sleeping heart rate and heart rate economy. Grip strength data was also available from a sex- and age-matched HIV-negative reference group. Median PAEE was 27.9 (interquartile range 17.4-39.8) kJ/kg per day and mean ± s.d. grip strength was 23.6 ± 6.7 kg. Advanced HIV disease predicted reduced levels of both physical activity and capacity; e.g. each unit viral load [log(1+copies/ml)] was associated with -15% PAEE (P < 0.001) and -1.0 kg grip strength (P < 0.001). Grip strength was 4.2 kg lower in patients compared to HIV-negative individuals (P < 0.001). Low body mass index (BMI) predicted poor physical activity and capacity independently of HIV status, e.g. BMI <16 was associated with -42% PAEE (P < 0.001) and -6.8 kg grip strength (P < 0.001) compared to BMI ≥18.5. The study shows that advanced HIV and malnutrition are associated with considerably lower levels of physical activity and capacity in patients at initiation of antiretroviral treatment.

Decline in locomotor functions over time in HIV-infected patients

OBJECTIVES

To assess changes in locomotor function in HIV-infected patients and to evaluate the determinants of variations in lower limb muscle performance.

DESIGN

Longitudinal study within the ANRS CO3 Aquitaine Cohort.

METHODS

Standardized locomotor tests, including global functional capacity [6-min walk distance (6MWD)] and lower limb muscle performance tests [five times sit-to-stand (5STS) test], were performed in HIV-infected adults at baseline and 2-year follow-up. Evolution of performances and determinants of 5STS time were studied in linear mixed-effects models.

RESULTS

At baseline (354 patients, 90% on antiretroviral treatment), median 5STS time was 9.8 s and 6MWD 549 m. Poorer performances were associated with falls, reported by 12% of 178 patients at follow-up. Estimated mean deterioration was +0.24 s/year (P < 10) for 5STS time and -11 m/year (P < 10) for 6MWD. In multivariable analyses, older age was associated with worse baseline 5STS time (+0.47 s/10-year age increase; P = 10), but not with further deterioration. Deterioration was greater in prior injecting drug users compared to others (difference in slope +0.62 s/year; P = 0.04). 5STS time at any time point was worse in patients with history of cerebral AIDS conditions (+2.47 s; P < 10) and diabetes (+0.95 s; P = 0.02) than in others. No significant associations were found for antiretroviral treatment type, viral load or CD4 cell count.

CONCLUSION

Compared to published data from healthy persons of similar age, baseline 5STS time and 6MWD were poorer in HIV-infected adults and associated with subsequent falls. Test performances deteriorated further over time. Age, diabetes, neurologic complications and injection drug use, rather than virologic factors, contribute to variations in lower limb muscle performance.

Effects of nutritional supplementation for HIV patients starting antiretroviral treatment: randomised controlled trial in Ethiopia

OBJECTIVES

To determine the effects of lipid based nutritional supplements with either whey or soy protein in patients with HIV during the first three months of antiretroviral treatment (ART) and to explore effects of timing by comparing supplementation at the start of ART and after three months delay.

DESIGN

Randomised controlled trial.

SETTING

Three public ART facilities in Jimma, Oromia region, Ethiopia.

PARTICIPANTS

Adults with HIV eligible for ART with body mass index (BMI) >16.

INTERVENTION

Daily supplementation with 200 g (4600 kJ) of supplement containing whey or soy during either the first three or the subsequent three months of ART.

OUTCOME MEASURES

Primary: lean body mass assessed with deuterium dilution, grip strength measured with dynamometers, and physical activity measured with accelerometer and heart rate monitors. Secondary: viral load and CD4 counts. Auxiliary: weight and CD3 and CD8 counts.

RESULTS

Of 318 patients enrolled, 210 (66%) were women, mean age was 33 (SD 9), and mean BMI was 19.5 (SD 2.4). At three months, participants receiving the supplements containing whey or soy had increased their lean body mass by 0.85 kg (95% confidence interval 0.16 kg to 1.53 kg) and 0.97 kg (0.29 kg to 1.64 kg), respectively, more than controls. This was accompanied by an increased gain of grip strength of 0.68 kg (-0.11 kg to 1.46 kg) for the whey supplement group and 0.93 kg (0.16 kg to 1.70 kg) for the soy supplement group. There were no effects on physical activity. Total weight gain increased by 2.05 kg (1.12 kg to 2.99 kg) and 2.06 kg (1.14 kg to 2.97 kg) for the whey and soy groups, respectively. In addition, in the whey supplement group overall CD3 counts improved by 150 cells/µL (24 to 275 cells/µL), of which 112 cells/µL (15 to 209 cells/µL) were CD8 and 25 cells/µL (-2 to 53 cells/µL) were CD4. Effects of the soy containing supplement on immune recovery were not significant. The effects of the two supplements, however, were not significantly different in direct comparison. Exploratory analysis showed that relatively more lean body mass was gained by patients with undetectable viral load at three months. Patients receiving delayed supplementation had higher weight gain but lower gains in functional outcomes.

CONCLUSIONS

Lipid based nutritional supplements improved gain of weight, lean body mass, and grip strength in patients with HIV starting ART. Supplements containing whey were associated with improved immune recovery. Trial registration Controlled-trials.com ISRCTN32453477.

Comparisons of creatinine and cystatin C for detection of kidney disease and prediction of all-cause mortality in HIV-infected women

BACKGROUND

Cystatin C could improve chronic kidney disease (CKD) classification in HIV-infected women relative to serum creatinine.

DESIGN

Retrospective cohort analysis.

METHODS

Cystatin C and creatinine were measured from specimens taken and stored during the 1999-2000 examination among 908 HIV-infected participants in the Women's Interagency HIV study (WIHS). Mean follow-up was 10.2 years. Predictors of differential glomerular filtration rate (GFR) estimates were evaluated with multivariable linear regression. The associations of baseline categories (<60, 60-90, and >90 ml/min per 1.73 m) of creatinine estimated GFR (eGFRcr), cystatin C eGFR (eGFRcys), and combined creatinine-cystatin C eGFR (eGFRcr-cys) with all-cause mortality were evaluated using multivariable Cox regression. The net reclassification index (NRI) was calculated to evaluate the effect of cystatin C on reclassification of CKD staging.

RESULTS

CKD risk factors were associated with lower eGFRcys and eGFRcr-cys values compared with eGFRcr. Relative to eGFR more than 90, the eGFR less than 60 category by eGFRcys (Adjusted hazard ratio: 2.56; 95% confidence interval: 1.63-4.02), eGFRcr-cys (3.11; 1.94-5.00), and eGFRcr (2.34; 1.44-3.79) was associated with increased mortality risk. However, the eGFR 60-90 category was associated with increased mortality risk for eGFRcys (1.80; 1.28-2.53) and eGFRcr-cys (1.91; 1.38-2.66) but not eGFRcr (1.20; 0.85-1.67). The overall NRI for mortality was 26% when reclassifying from eGFRcr to eGFRcys (P < 0.001) and was 20% when reclassifying from eGFRcr to eGFRcr-cys (P < 0.001).

CONCLUSION

The addition of cystatin C may improve mortality risk prediction by stages of kidney function relative to creatinine. CKD risk factors are associated with an overestimate of GFR by serum creatinine relative to cystatin C.