Cardiometabolic Disease in Human Immunodeficiency Virus-Infected Children

Heart Failure with Preserved Ejection Fraction in Children

Diastolic dysfunction (DD) refers to abnormalities in the mechanical function of the left ventricle (LV) during diastole. Severe LVDD can cause symptoms and the signs of heart failure (HF) in the setting of normal or near normal LV systolic function and is referred to as diastolic HF or HF with preserved ejection fraction (HFpEF). Pediatric cardiologists have long speculated HFpEF in children with congenital heart disease and cardiomyopathy. However, understanding the risk factors, clinical course, and validated biomarkers predictive of the outcome of HFpEF in children is challenging due to heterogeneous etiologies and overlapping pathophysiological mechanisms. The natural history of HFpEF varies depending upon the patient's age, sex, race, geographic location, nutritional status, biochemical risk factors, underlying heart disease, and genetic-environmental interaction, among other factors. Pediatric onset HFpEF is often not the same disease as in adults. Advances in the noninvasive evaluation of the LV diastolic function by strain, and strain rate analysis with speckle-tracking echocardiography, tissue Doppler imaging, and cardiac magnetic resonance imaging have increased our understanding of the HFpEF in children. This review addresses HFpEF in children and identifies knowledge gaps in the underlying etiologies, pathogenesis, diagnosis, and management, especially compared to adults with HFpEF.

Multi-Parametric Diagnostic Approach and Potential Markers of Early Onset Subclinical Cardiovascular Disease in a Cohort of Children, Adolescents and Young Adults Vertically Infected with HIV on cART

Background: HIV infection and lifelong cART are responsible of an increase in cardiovascular risk. The aim of this study was to describe the subclinical cardiovascular disease and to identify early markers of cardiovascular damage in adolescents and young adults vertically infected with HIV on cART, through an innovative multi-parametric approach. Methods: We enrolled 52 patients vertically infected with HIV. Demographic records, traditional cardiovascular risk factors, laboratory findings and echocardiographic measurements were collected in a one-year routine follow up. The echocardiographic examination included measurements of the 2D and 3D ejection fraction (EF), E/A ratio, E/E′ ratio, carotid intima media thickness (cIMT), flow-mediated dilation (FMD) and global longitudinal strain (GLS). Results: At the time of enrolment, all the patients were on cART therapy. The viral load was suppressed in 95% of them. EF was normal in 94.2% of patients (66 ± 7.2%), and GLS (mean value: −20.0 ± 2.5%) was reduced in 29% of patients. The cIMT mean value was higher than the 95th centile for sex and age in 73%, and FMD was impaired in 45% of patients. Clinically evident disease was found in three patients: dilative cardiomyopathy in one, thoracic-abdominal aneurysm Crawford type II with a bilateral carotid dilation in one and carotid plaque with 30% of stenosis in a third patient. Conclusions: This study confirms the presence of clinical and subclinical cardiovascular disease in a very young population vertically infected with HIV, underlining the importance of an early, multi-parametric cardiovascular follow up.

Ventricular and atrial functions assessed by speckle-tracking echocardiography in patients with human immunodeficiency virus

PURPOSE

Antiretroviral therapy (ART) has dramatically changed the clinical manifestation of human immunodeficiency virus (HIV) associated cardiomyopathy from severe left ventricular (LV) systolic dysfunction to a pattern of subclinical cardiac dysfunction. The aim of this study was to evaluate by speckle tracking echocardiography (STE) LV, right ventricular (RV), and biatrial functions in HIV-infected patients under different ART combinations.

METHODS

We consecutively included 128 HIV-infected patients (mean age 44.2 ± 10.1 years, 110 males) and 100 controls (mean age 42.1 ± 9.4 years, 83 males). Ventricular and atrial functions were assessed by both conventional and STE.

RESULTS

Although there was not any significant difference in conventional echocardiographic variables, HIV-infected patients had significantly lower LV global longitudinal strain (GLS), RV GLS, left atrial (LA) reservoir and conduit strain, and right atrial conduit strain. HIV patients receiving integrase strand transfer inhibitors and protease inhibitors (PI) had significantly lower LV GLS and LA conduit strain, while patients receiving non-nucleoside reverse transcriptase inhibitors and PI had significantly lower RV GLS than controls. CD4 count at the time of echocardiography was strongly correlated with LV GLS (r = .619, P < .001) and RV GLS (r = .606, P < .001).

CONCLUSION

Biventricular and atrial functions are subclinically impaired in HIV-infected patients. ART regimen may also affect myocardial functions.

HIV-infected Children in Malawi Have Decreased Performance on the 6-minute Walk Test With Preserved Cardiac Mechanics Regardless of Antiretroviral Treatment Status

AIM

The aims of this study were to 1) determine if cardiac disease can be detected in HIV-infected children by strain imaging and 2) to evaluate differences in exercise performance between HIV-infected children on antiretroviral therapy (ART) and HIV-infected children not yet on ART and in HIV-uninfected children by 6-minute walk tests (6MWTs).

METHODS

This cross-sectional study evaluated cardiac function by echocardiogram and exercise performance by 6MWT in HIV-infected and HIV-uninfected children 4-18 years of age in Lilongwe, Malawi. Analyses compared HIV uninfected, HIV infected not yet on ART, and HIV infected on ART. Comparisons used χ(2) test, t test, analysis of variance and multiple linear regression.

RESULTS

No differences were found in ejection fraction, shortening fraction or strain in 73 children not yet on ART, 149 on ART and 77 HIV-uninfected controls. As viral load increased, children had worse circumferential strain. In addition, children receiving ART had better circumferential strain than those not yet on ART. Increased CD4 percentage was associated with better longitudinal strain and farther 6MWT distance. As longitudinal strain worsened, the 6MWT distance decreased. HIV-infected children not yet on ART walked a mean of 25.8 m less than HIV-uninfected children, and HIV-infected children on ART walked 25.9 m less (P = 0.015 comparing 3 groups).

CONCLUSIONS

HIV-uninfected children performed better on the 6MWT than HIV-infected children. Lower viral load, being on ART, and higher CD4 percentage were associated with better strain measures. Better longitudinal strain was associated with a farther 6MWT distance. Overall, ejection fraction, shortening fraction and strain measures between groups were similar, so cardiac strain did not detect cardiac dysfunction in this young population.

Metabolic Syndrome in Children and Adolescents Living with HIV

BACKGROUND

Metabolic syndrome (MetS) is considered an independent risk factor for developing cardiovascular disease. It is well known that the prevalence of metabolic disorders have increased in pediatric HIV-infected children. The objective of this study is to assess the prevalence and characteristics of MetS in HIV-infected children and adolescents in Spain.

METHODS

A cross-sectional multicenter study in 152 patients from the pediatric cohort of the Spanish AIDS Research Network (CoRISpe) was performed. MetS was defined according to the new International Diabetes Federation (IDF) diagnostic criteria and the modified National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATP III) criteria. Measurements included anthropometry, waist circumference, blood pressure, fasting lipids, glucose and insulin and lipodystrophy assessment. Demographic, clinical, immunological, virological and antiretroviral therapy data were obtained from the Network database.

RESULTS

An abnormally low high-density lipoprotein-cholesterol level was the most prevalent disturbance (21.05%) found. Three patients met IDF criteria for MetS (1.97%), and MetS was significantly associated with lipohypertrophy (P=0.029) in the analysis. When the modified NCEP-ATP III criteria were used, the prevalence of MetS was 5.92% (9 patients), and MetS was significantly associated with Tanner stage ≥2 (P=0.041), lipohypertrophy (P=0.001) and higher Z scores for weight and body mass index (P=0.002 and P<0.001). Insulin resistance was observed in 17 patients (11.18%) and was associated with MetS (as per the modified NCEP-ATP III criteria) (P=0.03) and lower high-density lipoprotein-cholesterol values (P=0.036).

CONCLUSIONS

The prevalence of MetS in our cohort was 1.97% or 5.92%, depending on the diagnostic criteria used. MetS should be actively assessed, particularly in children who show lipohypertrophy.

Systemic Immune Activation Profiles of HIV-1 Subtype C-Infected Children and Their Mothers

Little is known about immune activation profiles of children infected with HIV-1 subtype C. The current study compared levels of selected circulating biomarkers of immune activation in HIV-1 subtype C-infected untreated mothers and their children with those of healthy controls. Multiplex bead array, ELISA, and immunonephelometric procedures were used to measure soluble CD14 (sCD14), beta-2 microglobulin (β2M), CRP, MIG, IP-10, and transforming growth factor beta 1 (TGF-β1). Levels of all 6 biomarkers were significantly elevated in the HIV-infected mothers and, with the exception of MIG, in their children (P < 0.01–P < 0.0001). The effects of antiretroviral therapy (ART) and maternal smoking on these biomarkers were also assessed. With the exception of TGF-β1, which was unchanged in the children 12 months after therapy, initiation of ART was accompanied by decreases in the other biomarkers. Regression analysis revealed that although most biomarkers were apparently unaffected by smoking, exposure of children to maternal smoking was associated with a significant increase in IP-10. These findings demonstrate that biomarkers of immune activation are elevated in HIV-infected children pre-ART and decline, with the exception of TGF-β1, after therapy. Although preliminary, elevation of IP-10 in smoke-exposed infants is consistent with a higher level of immune activation in this group.

Habitual nutrient intake in HIV-infected youth and associations with HIV-related factors

Few studies have evaluated habitual nutrient intake among HIV-infected youth in the United States, even though diet may influence disease progression and risk of comorbidities. This study determined habitual micronutrient and macronutrient intake in HIV-infected youth. HIV-infected subjects and healthy controls 1-25 years old were prospectively enrolled. Nutrient intake was assessed via 24-h dietary recalls performed every 3 months for 1 year and compared to recommended intake from the U.S. Dietary Reference Intakes (DRIs) and Acceptable Macronutrient Distribution Ranges (AMDRs). Subjects with two or more food recalls were analyzed (175 HIV(+) and 43 healthy controls). Groups were similar in age, race, sex, body mass index, and kilocalorie intake. In both groups, intake of several micronutrients was below the DRI. In addition, HIV(+) subjects had a lower percentage DRI than controls for vitamins A, D, E, pantothenic acid, magnesium, calcium, folate, and potassium. HIV(+) subjects' percentage caloric intake from fat was above the AMDR and was higher than controls. Caloric intake was negatively correlated with current and nadir CD4 count. Zinc, riboflavin, and magnesium percentage DRI were positively associated with current CD4 count. In HIV(+) subjects not on antiretroviral therapy, HIV-1 RNA levels were negatively correlated with protein intake. HIV(+) youth have an inadequate dietary intake of several essential nutrients and poorer dietary intake compared to controls. Intake of some nutrients was associated with important HIV-related factors. Further investigation is warranted to determine the impact of dietary intake of specific nutrients on HIV progression and chronic complication risk in this population.

Physical fitness in children infected with the human immunodeficiency virus: associations with highly active antiretroviral therapy

Obesity, sedentary lifestyles, and antiretroviral therapies may predispose HIV-infected children to poor physical fitness. Estimated peak oxygen consumption (VO(2) peak), maximal strength and endurance, and flexibility were measured in HIV-infected and uninfected children. Among HIV-infected children, anthropometric and HIV disease-specific factors were evaluated to determine their association with VO(2) peak. Forty-five HIV-infected children (mean age 16.1 years) and 36 uninfected children (mean age 13.5 years) participated in the study. In HIV-infected subjects, median viral load was 980 copies/ml (IQR 200-11,000 copies/ml), CD4% was 28% (IQR 15-35%), and 82% were on highly active antiretroviral therapy (HAART). Compared to uninfected children, after adjusting for age, sex, race, body fat, and siblingship, HIV-infected children had lower VO(2) peak (25.92 vs. 30.90 ml/kg/min, p<0.0001), flexibility (23.71% vs. 46.09%, p=0.0003), and lower-extremity strength-to-weight ratio (0.79 vs. 1.10 kg lifted/kg of body weight, p=0.002). Among the HIV-infected children, a multivariable analysis adjusting for age, sex, race, percent body fat, and viral load showed VO(2) peak was 0.30 ml/kg/min lower per unit increase in percent body fat (p<0.0001) and VO(2) peak (SE) decreased 29.45 (± 1 .62), 28.70 (± 1.87), and 24.09 (± 0.75) ml/kg/min across HAART exposure categories of no exposure, <60, and ≥ 60 months, respectively (p<0.0001). HIV-infected children had, in general, lower measures of fitness compared to uninfected children. Factors negatively associated with VO(2) peak in HIV-infected children include higher body fat and duration of HAART ≥ 60 months. Future studies that elucidate the understanding of these differences and mechanisms of decreased physical fitness should be pursued.

Pharmacotherapy of pediatric HIV infection

The delivery of safe and effective antiretroviral therapy to children and adolescents is crucial to save the lives of millions of children worldwide. The immunologic response to human immunodeficiency infection is closely related to a child's development and creates age-specific parameters for the evaluation of therapeutic response to antiretroviral therapy. Similarly, the development and maturation of organ systems involved in drug absorption, distribution, metabolism, and elimination determines significant changes in the pharmacokinetics of antiretroviral drugs throughout childhood. The authors review the evolution in treatment of pediatric HIV from infancy through adolescence.

Abnormal cardiac strain in children and young adults with HIV acquired in early life

BACKGROUND

Traditional measures of cardiac function are now often normal in adolescents and young adults treated with antiretroviral therapy for human immunodeficiency virus (HIV) infection. There is, however, evidence of myocardial abnormalities in adults with HIV. Cardiac strain analysis may detect impairment in cardiac function that may be missed by conventional measurements in this population.

METHODS

This was a retrospective study in which echocardiograms of HIV-infected subjects (n = 28) aged 7 to 29 years who participate in a natural history study of HIV acquired early in life were analyzed and compared with matched controls. Standard echocardiographic measures, along with speckle tracking-derived strain and strain rate, were assessed.

RESULTS

Among the HIV-infected subjects, the median CD4 count was 667 cells/mm(3), and the mean duration of antiretroviral therapy was 14.6 years. Ejection fractions and fractional shortening were normal. There were no significant differences in measures of systolic or diastolic function between the groups. The HIV-infected group had borderline increased left ventricular mass indices. Global longitudinal and circumferential strain and strain rate, as well as global radial strain rate, were significantly impaired in the HIV-infected group compared with controls. There were no associations identified between left ventricular mass index or strain indices and current CD4 count, CD4 nadir, HIV viral load, or duration of antiretroviral therapy.

CONCLUSIONS

HIV-infected participants demonstrated impaired strain and strain rate despite having normal systolic function and ejection fractions. Strain and strain rate may prove to be prognostic factors for long-term myocardial dysfunction. Therefore, asymptomatic children and young adults with long-standing HIV infection may benefit from these more sensitive measures.

Metabolic abnormalities and viral replication are associated with biomarkers of vascular dysfunction in HIV-infected children

OBJECTIVES

HIV-infected children may be at risk for premature cardiovascular disease. We compared levels of biomarkers of vascular dysfunction in HIV-infected children (with and without hyperlipidaemia) with those in HIV-exposed, uninfected (HEU) children enrolled in the Pediatric HIV/AIDS Cohort Study (PHACS), and determined factors associated with these biomarkers.

METHODS

A prospective cohort study was carried out. Biomarkers of inflammation [C-reactive protein (CRP), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP1)], coagulant dysfunction (fibrinogen and P-selectin), endothelial dysfunction [soluble intracellular cell adhesion molecule-1 (sICAM), soluble vascular cell adhesion molecule-1 (sVCAM) and E-selectin], and metabolic dysfunction (adiponectin) were measured in 226 HIV-infected and 140 HEU children. Anthropometry, body composition, lipids, glucose, insulin, HIV disease severity, and antiretroviral therapy were recorded.

RESULTS

The median ages of the children were 12.3 years in the HIV-infected group and 10.1 years in the HEU group. Body mass index (BMI) z-scores, waist and hip circumferences, and percentage body fat were lower in the HIV-infected children. Total and non-high-density lipoprotein (HDL) cholesterol and triglycerides were higher in HIV-infected children. HIV-infected children also had higher MCP-1, fibrinogen, sICAM and sVCAM levels. In multivariable analyses in the HIV-infected children alone, BMI z-score was associated with higher CRP and fibrinogen, but lower MCP-1 and sVCAM. Unfavourable lipid profiles were positively associated with IL-6, MCP-1, fibrinogen, and P- and E-selectin, whereas increased HIV viral load was associated with markers of inflammation (MCP-1 and CRP) and endothelial dysfunction (sICAM and sVCAM).

CONCLUSIONS

HIV-infected children have higher levels of biomarkers of vascular dysfunction than do HEU children. Risk factors associated with higher biomarkers include unfavourable lipid levels and active HIV replication.

Biomarkers of vascular dysfunction in children infected with human immunodeficiency virus-1

BACKGROUND

: We compared biomarkers of vascular dysfunction among HIV-infected children to a demographically similar group of uninfected children and determined factors associated with these biomarkers.

METHODS AND RESULTS

: We measured several biomarkers of vascular dysfunction: C-reactive protein (CRP), interleukin-6 (IL-6), and monocyte chemoattractant protein -1 (MCP-1) (inflammation); fibrinogen and P-selectin (coagulant dysfunction); soluble intracellular cell adhesion molecule-1 (sICAM), soluble vascular cell adhesion molecule-1 (sVCAM), and E-selectin (endothelial dysfunction); and leptin (metabolic dysfunction). Anthropometry, body composition, CD4%, HIV viral load, and antiretroviral therapy were recorded. Mean age was 14.8 years (106 HIV-infected children) and 12.3 years (55 control children). Sex and body mass index Z scores were similar. Infected children had higher sICAM, sVCAM, MCP-1, IL-6, and fibrinogen levels. E-selectin (P = 0.07), and CRP (P = 0.08) trended to be greater in the HIV group, yet leptin and P-selectin were similar. In multivariable analyses in the HIV-infected children alone, each 1 standard deviation increase in waist to hip ratio was associated with increases in sICAM (17%), MCP-1 (19%), IL6 (18%), and CRP (59%). CD4% was inversely associated with sVCAM, MCP-1, IL6, fibrinogen, and CRP.

CONCLUSIONS

: HIV-infected children have higher levels of biomarkers of vascular dysfunction than healthy children. Risk factors associated with these biomarkers include higher waist to hip ratios and HIV disease severity.

Clinical research directions in pediatric cardiology

PURPOSE OF REVIEW

Clinical research in pediatric cardiology is under-appreciated and under-funded, yet it has enormous implications for cardiovascular health and healthcare over the entire life-course. Renewed interest in federally funded clinical research makes it timely to propose a comprehensive research agenda that, with its associated rationale, will attract public funds for research into child cardiovascular health and disease.

RECENT FINDINGS

We propose here a comprehensive pediatric cardiology research agenda consisting of 22 topics and associated research questions. We describe the following five topics in more detail: the need for life-course studies of pediatric cardiac disease and epigenetic factors for later onset of cardiovascular effects; the need to study cardiometabolic disease risk in children; recent pediatric cardiology clinical trials and observational studies; the need to explore the role of physical activity in preventing and treating pediatric cardiology patients; and the need to develop and implement evidence-based interventions to manage pediatric cardiovascular problems.

SUMMARY

If the field of pediatric cardiology can adopt a comprehensive research agenda that identifies the most-needed studies, then research could be better coordinated, long-term and collaborative studies would be more readily organized and funded, and the overall financial and scientific efficiency of research in pediatric cardiology would be improved. Targeted research efforts are more likely to realize potential breakthroughs in areas such as genetic and epigenetic screening, biomarkers, cardioprotective strategies, life-course studies, long-term monitoring technologies, environmental influences on disease, evidence-based practice guidelines, and more rapid and safer development of drugs.