Effects of human immunodeficiency virus and metabolic complications on myocardial nutrient metabolism, blood flow, and oxygen consumption: a cross-sectional analysis

Functional capacity and ventilatory efficiency are preserved in well-controlled people living with human immunodeficiency virus/acquired immunodeficiency syndrome

To verify and compare the responses of the cardiopulmonary variables to the incremental test in physically inactive people living with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) (PLWHA) with well-controlled disease and physically inactive healthy subjects (non-HIV/AIDS). Participants performed a cardiopulmonary exercise test (CPX) on a treadmill. Data were analyzed using the Mann–Whitney test and Spearman correlation. Nine PLWHA (5 women) and 9 non-HIV/AIDS gender and activity level-matched controls were included in the data analysis. Data are expressed in median (range). No difference was shown in the PLWHA group when compared to the control group in functional capacity (peak oxygen consumption [VO_2peak]: 29.9 (20.9–36.4) mL/kg/min vs. 32.2 (24.5–39.4) mL/kg/min) and ventilatory efficiency (oxygen uptake efficiency slope [OUES]: 2,058 [1,474–3,204] vs. 2,612 [1,383–4,119]; minute ventilation carbon dioxide production slope: 27.4 [22.5–33.6] vs. 27.5 [20.4–38.1]). The results are also similar to maximal heart rate, oxygen pulse, gas exchange threshold, respiratory compensation point, heart rate recovery, and half-time of VO_2peak recovery. OUES had a strong correlation with VO_2peak in the PLWHA group (r_s=0.70, P=0.04) and control group (r_s=0.78, P=0.02). The results of this study indicate that functional capacity and ventilatory efficiency in PLWHA with well-controlled disease are preserved and are not different from sedentary subjects. In this sense, when CPX is unavailable, the aerobic assessment and prescription could be based on simpler procedures used in healthy subjects.

Cardiac Steatosis in HIV-A Marker or Mediator of Disease?

Although people living with HIV (PLHIV) are approaching normal life expectancy, a limitation to achieving this goal is managing the higher prevalence of co-morbidities, including cardiovascular disease. Whilst ischaemic heart disease likely contributes to a large proportion of cardiac disease in the modern era of treatment, cardio-metabolic disease, including cardiac steatosis, akin to obesity-related heart disease, is also a possible mechanism of increased cardiac morbidity and mortality. HIV and other metabolic and inflammatory diseases affecting the heart, including obesity, share many cardio-metabolic abnormalities, with increased pericardial and myocardial fat content, in association with chronic systemic inflammatory changes and alterations in cardiac metabolism. Understanding the mechanisms of HIV-associated cardiac steatosis remains an important challenge, as managing the untreated metabolic and inflammatory precipitants may substantially improve cardiac outcomes for PLHIV.

Cerebrospinal fluid metabolomics implicate bioenergetic adaptation as a neural mechanism regulating shifts in cognitive states of HIV-infected patients

OBJECTIVES

To identify prognostic surrogate markers for change in cognitive states of HIV-infected patients.

DESIGN

Longitudinal cerebrospinal fluid (CSF) samples were collected from 98 HIV-infected patients identified by temporal change in cognitive states classified as normal, stably impaired, improving and worsening.

METHODS

The metabolic composition of CSF was analysed using H nuclear magnetic resonance (H NMR) spectroscopy that focused on energy metabolites. Metabolic biomarkers for cognitive states were identified using multivariate partial least squares regression modelling of the acquired spectra, combined with nonparametric analyses of metabolites with clinical features.

RESULTS

Multivariate modelling and cross-validated recursive partitioning identified several energy metabolites that, when combined with clinical variables, classified patients based on change in neurocognitive states. Prognostic identification for worsening was achieved with four features that included no change in a detectable plasma viral load, elevated citrate and acetate; decreased creatine, to produce a model with a predictive accuracy of 92%, sensitivity of 88% and 96% specificity. Prognosis for improvement contained seven features that included first visit age less than 47 years, new or continued use of antiretrovirals, elevated glutamine and glucose; decreased myo-inositol, β-glucose and creatinine to generate a model with a predictive accuracy of 92%, sensitivity of 100% and specificity of 84%.

CONCLUSION

These CSF metabolic results suggest that worsening cognitive status in HIV-infected patients is associated with increased aerobic glycolysis, and improvements in cognitive status are associated with a shift to anaerobic glycolysis. Dietary, lifestyle and pharmacologic interventions that promote anaerobic glycolysis could protect the brain in setting of HIV infection with combined antiretroviral therapy.

Cardiac mechanics in patients with human immunodeficiency virus: a study of systolic myocardial deformation in children and young adults

Human immunodeficiency virus (HIV) infection causes dysfunction of different organ systems. Myocardial diastolic dysfunction has been reported previously in an adult HIV population. Our aim was to study myocardial strain in children and young adults infected by HIV who have apparently normal ejection fraction. Forty HIV-infected patients (mean age 20.6 ± 1.5 years) with normal ejection fraction and 55 matched normal controls (mean age 17 ± 1.5 years) were studied by two-dimensional echocardiogram. The images were stored then exported to velocity vector imaging software for analysis. Measures considered were left-ventricular peak global systolic strain (LV S) and strain rate (LV SR) as well as right-ventricular peak global systolic strain (RV S) and strain rate (RV SR). Circumferential measures of the left ventricle included the following: LV circumferential peak global systolic strain (LV circ S), strain rate (LV circ SR), radial velocity (LV rad vel), and rotational velocity (LV rot vel) at the level of the mitral valve. Statistical significance was set at p < 0.05. The means of all longitudinal deformation parameters were significantly lower in HIV patients compared with normal controls: LV S (-14.15 vs. -19.31), LV SR (-0.88 vs. -1.30), RV S (-19.58 vs. -25.09), and RV SR (-1.34 vs. -2.13), respectively (p < 0.05). LV rot vel was lower in patients compared with controls (43.23 vs. 51.71, p = 0.025). LV circ S, LV circ SR, and LV rad vel showed no significant difference between the two groups (p ≥ 0.05). HIV infection affects longitudinal systolic cardiac strain and strain rate in children and young adults. Normal ejection fraction might be attributed to preserved circumferential myocardial deformation. Strain and strain rate may help identify HIV patients at high risk for cardiac dysfunction and allow early detection of silent myocardial depression.

Pilot study of pioglitazone and exercise training effects on basal myocardial substrate metabolism and left ventricular function in HIV-positive individuals with metabolic complications

BACKGROUND

Individuals with HIV infection and peripheral metabolic complications have impaired basal myocardial insulin sensitivity that is related to left ventricular (LV) diastolic dysfunction. It is unknown whether interventions shown to be effective in improving peripheral insulin sensitivity can improve basal myocardial insulin sensitivity and diastolic function in people with HIV and peripheral metabolic complications.

OBJECTIVE

In a pilot study, we evaluated whether the peroxisome proliferator-activated receptor-gamma (PPAR-γ) agonist pioglitazone or combined endurance and resistance exercise training improves basal myocardial insulin sensitivity and diastolic function in HIV+ adults with peripheral metabolic complications.

DESIGN

Twenty-four HIV+ adults with metabolic complications including peripheral insulin resistance were randomly assigned to 4 months of pioglitazone (PIO; 30 mg/d) or supervised, progressive endurance and resistance exercise training (EXS; 90-120 min/d, 3 d/wk). Basal myocardial substrate metabolism was quantified by radioisotope tracer methodology and positron emission tomography (PET) imaging, and LV function was measured by echocardiography.

RESULTS

Twenty participants completed the study. Neither PIO nor EXS resulted in a detectable improvement in basal myocardial insulin sensitivity or diastolic function. Post hoc analyses revealed sample sizes of more than 100 participants are needed to detect significant effects of these interventions on basal myocardial insulin sensitivity and function.

CONCLUSIONS

PIO or EXS alone did not significantly increase basal myocardial insulin sensitivity or LV diastolic function in HIV+ individuals with peripheral metabolic complications.

Relationships among HIV infection, metabolic risk factors, and left ventricular structure and function

Our objective was to determine if the presence of metabolic complications (MC) conveyed an additional risk for left ventricular (LV) dysfunction in people with HIV. HIV⁺ and HIV⁻ men and women were categorized into four groups: (1) HIV⁺ with MC (43±7 years, n=64), (2) HIV⁺ without MC (42±7 years, n=59), (3) HIV⁻ with MC (44±8 years, n=37), or (4) HIV⁻ controls without MC (42±8 years, n=41). All participants underwent two-dimensional (2-D), Doppler, and tissue Doppler echocardiography. Overall, the prevalence of systolic dysfunction (15 vs. 4%, p=0.02) and LV hypertrophy (9 vs. 1%, p=0.03) was greater in HIV⁺ than in HIV⁻ participants. Participants with MC had a greater prevalence of LV hypertrophy (10% vs. 1%). Early mitral annular velocity during diastole was significantly (p<0.005) lower in groups with MC (HIV⁺/MC⁺: 11.6±2.3, HIV⁻/MC⁺: 12.0±2.3 vs. HIV⁺/MC⁻: 12.4±2.3, HIV⁻/MC⁻: 13.1±2.4 cm/s) and tended to be lower in groups with HIV (p=0.10). However, there was no interaction effect of HIV and MC for any systolic or diastolic variable. Regardless of HIV status, participants with MC had reduced LV diastolic function. Although both the presence of MC and HIV infection were associated with lower diastolic function, there was no additive negative effect of HIV on diastolic function beyond the effect of MC. Also, HIV was independently associated with lower systolic function. Clinical monitoring of LV function in individuals with metabolic risk factors, regardless of HIV status, is warranted.

Comprehensive cardiac magnetic resonance imaging and spectroscopy reveal a high burden of myocardial disease in HIV patients

BACKGROUND

HIV infection continues to be endemic worldwide. Although treatments are successful, it remains controversial whether patients receiving optimal therapy have structural, functional, or biochemical cardiac abnormalities that may underlie their increased cardiac morbidity and mortality. The purpose of this study was to characterize myocardial abnormalities in a contemporary group of HIV-infected individuals undergoing combination antiretroviral therapy.

METHODS AND RESULTS

Volunteers with HIV who were undergoing combination antiretroviral therapy and age-matched control subjects without a history of cardiovascular disease underwent cardiac magnetic resonance imaging and spectroscopy for the determination of cardiac function, myocardial fibrosis, and myocardial lipid content. A total of 129 participants were included in this analysis. Compared with age-matched control subjects (n=39; 30.23%), HIV-infected subjects undergoing combination antiretroviral therapy (n=90; 69.77%) had 47% higher median myocardial lipid levels (P <0.003) and 74% higher median plasma triglyceride levels (both P<0.001). Myocardial fibrosis, predominantly in the basal inferolateral wall of the left ventricle, was observed in 76% of HIV-infected subjects compared with 13% of control subjects (P<0.001). Peak myocardial systolic and diastolic longitudinal strain were also lower in HIV-infected individuals than in control subjects and remained statistically significant after adjustment for available confounders.

CONCLUSIONS

Comprehensive cardiac imaging revealed cardiac steatosis, alterations in cardiac function, and a high prevalence of myocardial fibrosis in a contemporary group of asymptomatic HIV-infected subjects undergoing combination antiretroviral therapy. Cardiac steatosis and fibrosis may underlie cardiac dysfunction and increased cardiovascular morbidity and mortality in subjects with HIV.

Interventions to address chronic disease and HIV: strategies to promote exercise and nutrition among HIV-infected individuals

Food insecurity, micronutrient deficits, dyslipidemia, insulin resistance, obesity, cardiovascular disease, and bone disorders complicate the treatment of HIV infection. Nutrition and exercise interventions can be effective in ameliorating these symptoms that are associated with HIV and antiretroviral therapy (ART). In this literature review, we examine the most recent nutrition and exercise interventions for HIV-infected patients. Macronutrient supplementation can be useful in treating malnutrition and wasting. Multivitamin (vitamin B complex, vitamin C, and vitamin E) supplements and vitamin D may improve quality of life and decrease morbidity and mortality. Nutritional counseling and exercise interventions are effective for treating obesity, fat redistribution, and metabolic abnormalities. Physical activity interventions improve body composition, strength, and fitness in HIV-infected individuals. Taken collectively, the evidence suggests that a proactive approach to nutrition and physical activity guidance and interventions can improve outcomes and help abrogate the adverse metabolic, cardiovascular, and psychological consequences of HIV and its treatments.

Reduced diastolic function and left ventricular mass in HIV-negative preadolescent children exposed to antiretroviral therapy in utero

OBJECTIVE

Abnormalities in left ventricular morphology and function have been reported in HIV-negative infants exposed to antiretroviral therapy (ART) in utero that persists throughout preschool age. The objective of this study was to determine if these abnormalities persist, resolve, or worsen during preadolescence.

DESIGN

Cross-sectional observation study.

METHODS

Thirty HIV-negative children born to HIV-positive women and exposed to ART in utero (mean age 8 ± 2 years, 37% female, 74% African-American) and 30 HIV-negative children born to HIV-negative women (mean age 8 ± 3 years, 37% female, 76% African-American) underwent two-dimensional Doppler, tissue Doppler, and strain echocardiography to evaluate left ventricular systolic and diastolic function.

RESULTS

Weight, body surface area, heart rate and blood pressure were similar between groups. For the ART-exposed group, left ventricular mass index was lower (60 ± 9 vs. 67 ± 12 g/m, P < 0.02) and early diastolic annular velocity was lower (15.0 ± 2.2 vs. 16.3 ± 2.5 cm/s, P < 0.03) compared to controls. Left ventricular systolic function did not differ between groups. Lower maternal third trimester CD4 count was associated with lower early diastolic annular velocity; other non-HIV-related variables including cocaine use and increased maternal age correlated with lower left ventricular mass index.

CONCLUSIONS

Abnormalities in left ventricular systolic performance previously reported in HIV-negative infants and preschool aged children exposed to ART in utero were not apparent in preadolescent children. Left ventricular diastolic relaxation was reduced compared with controls suggesting residual effects of ART exposure on left ventricular diastolic function. Larger, longitudinal studies are necessary to confirm these observations.