Myocardial extracellular volume fraction is positively associated with activated monocyte subsets among cART-treated persons living with HIV in South Africa.

BACKGROUND: Despite treatment with combination antiretroviral therapy (cART), persons living with HIV (PLWH) are at higher risk of cardiac structural abnormalities that may presage clinical heart failure, including myocardial fibrosis. This study assessed whether circulating cellular and soluble protein markers of immune activation cross-sectionally associate with myocardial fibrosis among cART-treated PLWH in South Africa. METHODS: Participants were enrolled in Khayelitsha township near Cape Town, SA. Cardiac magnetic resonance imaging was performed. Plasma protein biomarkers were measured using enzyme-linked immunoassays and monocyte phenotypes were evaluated using flow cytometry. Associations were assessed using multivariable linear and logistic regression. RESULTS: Among 69 cART-treated PLWH, mean (SD) age was 48 (10) years, 71% were female, and time since HIV diagnosis was 9 (6) years. Evidence of left ventricular fibrosis by late gadolinium enhancement was present in 74% of participants and mean (SD) extracellular volume fraction (ECV) was 30.9 (5.9)%. Degree of myocardial fibrosis/inflammation measured by ECV was positively associated with percentages of circulating non-classical and intermediate monocyte phenotypes reflecting inflammation and tissue injury. CONCLUSION: These data generate hypotheses on possible immune mechanisms of HIV-associated non-ischemic myocardial disease, specifically among cART-treated PLWH in sub-Saharan Africa, where the majority of the HIV burden exists globally.

Predicting eyes at risk for rapid glaucoma progression based on an initial visual field test using machine learning.

OBJECTIVE: To assess whether machine learning algorithms (MLA) can predict eyes that will undergo rapid glaucoma progression based on an initial visual field (VF) test. DESIGN: Retrospective analysis of longitudinal data. SUBJECTS: 175,786 VFs (22,925 initial VFs) from 14,217 patients who completed ≥5 reliable VFs at academic glaucoma centers were included. METHODS: Summary measures and reliability metrics from the initial VF and age were used to train MLA designed to predict the likelihood of rapid progression. Additionally, the neural network model was trained with point-wise threshold data in addition to summary measures, reliability metrics and age. 80% of eyes were used for a training set and 20% were used as a test set. MLA test set performance was assessed using the area under the receiver operating curve (AUC). Performance of models trained on initial VF data alone was compared to performance of models trained on data from the first two VFs. MAIN OUTCOME MEASURES: Accuracy in predicting future rapid progression defined as MD worsening more than 1 dB/year. RESULTS: 1,968 eyes (8.6%) underwent rapid progression. The support vector machine model (AUC 0.72 [95% CI 0.70-0.75]) most accurately predicted rapid progression when trained on initial VF data. Artificial neural network, random forest, logistic regression and naïve Bayes classifiers produced AUC of 0.72, 0.70, 0.69, 0.68 respectively. Models trained on data from the first two VFs performed no better than top models trained on the initial VF alone. Based on the odds ratio (OR) from logistic regression and variable importance plots from the random forest model, older age (OR: 1.41 per 10 year increment [95% CI: 1.34 to 1.08]) and higher pattern standard deviation (OR: 1.31 per 5-dB increment [95% CI: 1.18 to 1.46]) were the variables in the initial VF most strongly associated with rapid progression. CONCLUSIONS: MLA can be used to predict eyes at risk for rapid progression with modest accuracy based on an initial VF test. Incorporating additional clinical data to the current model may offer opportunities to predict patients most likely to rapidly progress with even greater accuracy.

Myocardial Fibrosis Among Antiretroviral Therapy-Treated Persons With Human Immunodeficiency Virus in South Africa.

BACKGROUND: Heart failure is a prominent cardiovascular disease (CVD) manifestation in sub-Sarahan Africa. Myocardial fibrosis is a central feature of heart failure that we aimed to characterize among persons with human immunodeficiency virus (PWH) in South Africa. METHODS: Cardiovascular magnetic resonance (CMR) imaging was performed among PWH with viral suppression and uninfected controls, both free of known CVD. Plasma levels of N-terminal pro B-type natriuretic peptide (NT-proBNP) were measured. Comparisons by human immunodeficiency virus (HIV) status were made using linear and logistic regression, adjusted for age, sex, and hypertension. RESULTS: One hundred thirty-four PWH and 95 uninfected persons completed CMR imaging; age was 50 and 49 years, with 63% and 67% female, respectively. Compared with controls, PWH had greater myocardial fibrosis by extracellular volume fraction ([ECV] absolute difference, 1.2%; 95% confidence interval [CI], 0.1-2.3). In subgroup analyses, the effect of HIV status on ECV was more prominent among women. Women (vs controls) were also more likely to have elevated NT-proBNP levels (>125 pg/mL; odds ratio, 2.4; 95% CI, 1.0-6.0). Among all PWH, an elevated NT-proBNP level was associated with higher ECV (3.4% higher; 95% CI, 1.3-5.5). CONCLUSIONS: Human immunodeficiency virus disease may contribute to myocardial fibrosis, with an effect more prominent among women. Research is needed to understand heart failure risk among PWH within sub-Saharan Africa.

Genome-wide association study identifies genetic variants in GOT1 determining serum aspartate aminotransferase levels.

We carried out a genome-wide association study of serum aspartate aminotransferase (AST) activity in 866 Amish participants of the Heredity and Phenotype Intervention Heart Study and identified significant association of AST activity with a cluster of single nucleotide polymorphisms located on chromosome 10q24.1 (peak association was rs17109512; P=2.80E-14), in the vicinity of GOT1, the gene encoding cytosolic AST (cAST). Sequencing of GOT1 revealed an in-frame deletion of three nucleic acids encoding asparagine at position 389 c.1165_1167delAAC (p.Asn389del) in the gene. Deletion carriers had significantly lower AST activity levels compared with homozygotes for the common allele (mean±s.d.: 10.0±2.8 versus 18.8±5.2 U l(-1); P=2.80E-14). Further genotyping of the deletion in other Amish samples (n=1932) identified an additional 20 carriers (minor allele frequency (MAF)=0.0052). The deletion was not detected in 647 outbred Caucasians. Asn at codon 389 is conserved among known mammalian cASTs. In vitro transient transfection of wild-type and mutant cAST indicated that mutant cAST protein was barely detectable in the cells. Furthermore, even after correction for cAST expression, mutant cAST had markedly diminished enzymatic activity. Remarkably, we did not find any association between the deletion and metabolic traits including serum fasting glucose or insulin, fasting and post-meal lipids, inflammatory markers, or sub-clinical markers of cardiovascular disease. In conclusion, we discovered a rare in-frame deletion in GOT1 gene, which inactivates cAST enzyme in the Old Order Amish. This finding will help us to understand structure and function of the enzyme and would be useful for predicting serum AST levels.