Diastolic dysfunction in people with HIV without known cardiovascular risk factors in Western Kenya

Objectives

Diastolic dysfunction (DD) has been reported to be highly prevalent in people living with HIV (PLWH) on antiretroviral therapy (ART) leading to the hypothesis that it may be an early marker of myocardial disease. Our objective was to evaluate the prevalence of DD in people living with human immunodeficiency virus without known history of diabetes or hypertension in Western Kenya.

Methods

In this cross-sectional study in western Kenya, 110 PLWH on ART and without known diabetes or hypertension were matched for age ±5 years and sex to HIV-uninfected controls. Study participants underwent a comprehensive two-dimensional echocardiogram and laboratory testing.

Results

The mean (SD) age in the HIV-positive group was 42.9 (8.6) years compared with 42.1 (12.9) years in the HIV-uninfected group. Mean (SD) CD4 +T cell count for the HIV-positive group was 557 (220) cells/ml. Mean systolic and diastolic blood pressures were within the normal range and comparable between the two groups. Mean body mass index was 25.2 (5.4) kg/m² and 26.3 (5.4) kg/m² in HIV-positive and uninfected participants, respectively. There was only 1 (0.9 %) case of DD in each group. Despite low prevalence of DD, PLWH had 5.76 g/m² higher left ventricular mass index (p=0.01) and 2.77 mL/m² larger left atrial volume (p=0.02) compared with the HIV-negative group after adjusting for risk factors associated with DD.

Conclusion

Contrary to prior reports, DD in PLWH was low. Environmental and cardiovascular disease risk factors such as diabetes and hypertension may be significant modifiers for development and progression of DD in PLWH.

Abstract 933: Integrated Omics Analysis of Diabetic Heart Failure in Human Myocardium

Background: Patients with diabetes mellitus (DM) have a higher risk of heart failure (HF). While metabolic dysregulation has been well-established in HF and DM separately, molecular mechanisms associated with diabetic HF are incompletely understood. Thus, we sought to test the overarching hypothesis that cardiac metabolic programming is distinct in diabetic HF compared to DM and HF individually.

Methods: RNA-sequencing and targeted metabolomics profiles were completed on human myocardial tissue from 54 unique individuals received from the Duke Human Heart Biorepository and the University of Colorado. Multi-omics profiles of cardiac tissue from 4 groups were compared: a) controls with no clinical evidence of DM or HF (n = 12), b) DM-only (n = 15), c) HF-only (n = 10), and d) HF+DM (n = 17).

Results: After using statistical criteria to prioritize genes, we looked for genes that function together or modulate the same activity. Genes encoding producers of reactive oxygen species (ROS), DUOX2, DUOXA2, and DUOXA1, were differentially upregulated in diabetic-HF, compared to DM or HF alone (FDR HF+DM vs DM-only/HF-only = 6.6 x 10 -7 /2.2 x 10 -4 , 7.7 x 10 -3 /6.7 x 10 -3 , and 3.6 x 10 -6 /0.013, respectively). Modulators of mTOR signaling, ERBB3, ERBB4, and PIK3R3, were also differentially regulated in diabetic-HF (FDR HF+DM vs DM-only/HF-only = 1.4 x 10 -3 /0.010, 0.012/7.4 x 10 -3 , and 0.011/9.3 x 10 -3 , respectively). Gene set enrichment analysis supported our focus on these genes; top enriched gene sets included mTOR signaling and processes related to oxidative stress response. In our metabolomics data, long chain acylcarnitines (AC) and ceramides (Cer) are decreased in diabetic-HF. For example, C20:1 AC can be converted to C20:1 Cer and accumulation of both is diminished in diabetic-HF (FDR = 0.0032 and 0.035, respectively).

Conclusions: We found that diabetic-HF was characterized by a distinct omics profile consistent with increased ROS production, diminished AC and Cer accumulation, and modulation of mTOR signaling. The fact that ceramide accumulation has been previously associated with oxidative stress and also linked to ERBB and PI3K pathways suggests that these data may reveal a unique regulation of these pathways in diabetic-HF.

Clinical and Echocardiographic Predictors of Outcomes in Patients With Pulmonary Hypertension

In pulmonary hypertension (PH), measurement of various echocardiographic parameters that assess right heart function is recommended by current clinical guidelines. Limited data exists on the combined value of clinical and echocardiographic parameters in precapillary PH in the modern era of therapy. We examined the association of clinical and echocardiographic parameters with surrogate outcomes (6-minute walk distance) and hard outcomes (hospitalization or death) in patients with precapillary PH. A cohort of patients with an established diagnosis of precapillary PH who underwent transthoracic echocardiography at the Duke Echo Lab were prospectively enrolled from 2010 to 2014. Univariable and multivariable models were constructed to examine the relation of clinical and echocardiographic parameters with surrogate and hard outcomes. Of the 98 patients with analyzable echocardiograms with good image quality, 85 were woman, mean age was 59.4 years, and 47% had ≥World Health Organization functional class III symptoms. The mean 6-minute walk distance was 354(±132) m, and 83% were on pulmonary arterial hypertension medications. At 24 months, the cumulative incidence rate for hospitalization or death was 47%. In univariable analyses, the REVEAL (Registry to Evaluate Early and Long-term PAH Disease Management) risk score (HR 1.72 per 1 SD (2.81) increment, 95% CI 1.34, 2.22; p=<0.001), RV global longitudinal strain (RVGLS) (HR 1.54 per 1 SD (5.31) worsening, 95% CI , 2.12; p=0.008) and log-2 NT proBNP (HR 1.43 per 1-fold increase, 95% CI 1.25, 1.63; p=<0.001) were significantly associated with hospitalization or death.

Alternative Methods of Mitigating Automation Distrust Impacts

Previous research into the incorporation of configural justification displays in an unreliable automated command and control environment has shown that they significantly improve operator decision time based upon system recommendations for courses of action. The objective of this research was to determine if different styles of configural displays would affect this decision time. Results from experimentation with Theater High Altitude Area Defense (THAAD) soldiers shows that the type of justification aid does not affect decision time or accuracy of decisions. Rather, soldiers monitoring these displays may have relied on color rather than spatial plots when periodically asked by the computer to authorize recommendations for courses of action.

Reduced force production during low blood flow to the heart correlates with altered troponin I phosphorylation

A rat model of low myocardial blood flow was established to test the hypothesis that post-translational changes to proteins of the thin and thick muscle filaments correlate with decreased cardiac contractility. Following 3 days of low blood flow by constriction of the left anterior descending artery, rat hearts demonstrated a reduction in fractional shortening at rest and a relative decline in fractional shortening when challenged with high dose versus low dose dobutamine, reflecting reduced energy reserves. Permeabilized fibers from low blood flow hearts demonstrated a decline in maximum force per cross-section and Ca2+ sensitivity as compared to their sham operated counterparts. An examination of sarcomeric proteins by twodimensional gel electrophoresis, mass spectrometry, and phospho-specific antibodies provided evidence for Ser23/24 and Ser43/45 phosphorylation of troponin I (TnI). Total TnI phosphorylation was not different between the groups, but Ser23/24 phosphorylation declined with low blood flow, implying an accompanying increase in phosphorylation at other sites of TnI. Affinity chromatography demonstrated that TnI from low blood flow myocardium had reduced relative affinity to Ca2+ bound troponin C compared to TnI from sham operated hearts, providing a mechanism for reduced Ca2+ sensitivity of force production in low blood flow fibers. These findings suggest that altered TnI function, due to changes in the distribution of phosphorylated sites, is an early contributor to reduced contractility of the heart.

Exposure to azide markedly decreases the abundance of mRNAs encoding cholesterol synthetic enzymes and inhibits cholesterol synthesis

This study was performed to identify genes that are regulated in the adaptive response to prolonged inhibition of oxidative phosphorylation. Gene microarray analysis in control Clone 9 cells and Clone 9 cells exposed to 5 mM azide for 24 h was carried out as a condition of "Chemical hypoxia." Among several hundred mRNAs whose abundances were either increased or decreased, we noted that the abundance of mRNAs encoding enzymes that catalyze the sequential steps of cholesterol synthesis was decreased; this finding was verified by real-time PCR. Exposure to azide for 24 h markedly inhibited the biosynthesis of cholesterol by approximately 90% and decreased the cellular content of cholesterol by 30%, similar results were observed in HepG2 cells. The abundance of sterol regulatory element binding protein (SREBP)-2 mRNA decreased to 0.37 and 0.25 that of controls after 2 and 24 h exposure, respectively. After 24 h of exposure to azide the precursor and nuclear forms of SREBP-2 protein decreased by approximately 80% and approximately 50%, respectively. Stimulation of AMP-activated protein kinase (AMPK) by AICAR in Clone 9 cells increased the abundance of mRNAs encoding cholesterol biosynthetic enzymes and that of SREBP-1c, and had no effect on SREBP-2 mRNA abundance. We conclude that the decrease in the abundance of multiple mRNAs encoding cholesterol biosynthetic enzymes may be mediated by decreased expression of SREBP-2 mRNA and protein and does not involve stimulation of AMPK. The decrease in SREBP-2 mRNA and protein abundance in the face of decreased cell cholesterol content raises the possibility of a novel regulatory pathway.

Immunolocalization of transforming growth factor-beta1 during follicular development and atresia in the mouse ovary

In each estrous cycle not all follicles recruited grow to ovulate, as some degenerate through the process of atresia. Apoptosis is the mechanism underlying follicle atresia. TGF-beta1 has been implicated in the induction and promotion of apoptosis in many cell types and it is expressed in the ovary. In this study immunohistochemistry was used to localize TGF-beta1 in order to correlate the growth factor expression with morphological follicular atresia during diestrus in mice. Small and medium sized follicles had no staining for TGF-beta1 in the granulosa or theca cell layer. Weak to moderate TGF-beta1 expression was present in the theca cells of both large healthy and atretic antral follicles. Large healthy antral follicles showed weak granulosa staining but this was not observed in atretic follicles. Strong TGF-beta1 staining was present in the interstitial, corpus luteum and oocytes of all follicle stages. These results suggest that in the mouse TGF-beta1 promote follicular growth and differentiation rather than follicular atresia.

Platelet-induced granulocyte aggregation in vitro

Recent studies have shown that the response of granulocytes to stimulation is increased by the presence of platelets. Using an assay based on counting aggregates with a Coulter Counter, we found that heparinized or citrated platelet-rich plasma directly caused aggregation of isolated granulocytes. Platelets themselves were frequently present within the granulocyte aggregates. The degree of aggregation depended on the platelet:granulocyte ratio, and increased over a 2--5 min period of mixing, with a slower increase thereafter. Aggregation was calcium-dependent, increased by stimulation of the platelets with ADP or collagen but not serotonin, and only slightly reduced by a thrombin inhibitor (hirudin, at concentrations up to 0.9 U/ml). A similar adhesive interaction in vivo might be relevant to thrombotic and ischaemic pathology.

[Correlation between the results of Doppler velocimetry with spectral analysis and the viscosity of cord blood]

The contribution of rheological factors to be impedance of blood flow in the umbilical artery as determined by continuous wave Doppler ultrasound was investigated. Of the 51 pregnancies recruited, six were complicated by pre-eclampsia, 10 by intrauterine growth retardation, 15 by both pre-eclampsia and fetal growth retardation, and there were 20 controls. A significant correlation was demonstrated between both plasma viscosity and gestational age and the resistance index used to characterize the Doppler waveform. Multiple regression analysis demonstrated that changes in plasma viscosity explained 55 p. cent of the variance seen in the resistance index and that this was statistically significant. This finding is, however, unlikely to be of clinical significance as whole blood viscosity had an insignificant effect on the impedance in the umbilical artery. We postulate that vascular factors such as the number and calibre of the placenta arterioles are a more important determinant of umbilical artery impedance.

Changes in the flow properties of white blood cells after acute myocardial infarction

Because they can obstruct blood vessels and release noxious substances, white blood cells may contribute to the development of tissue ischaemia. The flow properties of white cells were tested after myocardial infarction, by measuring the filtration rates of cell suspensions through 8 microns pore filters. Compared with mononuclear cells from age matched controls, mononuclear cells from patients with infarction showed impaired filterability within the first day after the onset of pain; this condition persisted for at least two days and by day 10 it was improved. On day 1, granulocyte filterability and the proportion showing morphological evidence of activation were nearly normal. By day 3 the flow resistance and activation had increased, but the changes seen depended on the age of the patient. The filterability and activation of granulocytes from patients aged less than 60 were significantly increased from day 1, whereas there were no changes in granulocytes from patients aged greater than 60 years. Suspensions of unfractionated white cells showed changes intermediate between the mononuclear cells and granulocytes. A group of five patients who presented with chest pain but who were subsequently found not to have had an infarction showed no evidence of abnormal filterability or activation. The changes in filterability probably reflect white cell activation, which may have an adverse effect on the perfusion of the ischaemic myocardium.

Correlation between Doppler flow velocity waveforms and cord blood viscosity

The contribution of rheological factors to the impedance of blood flow in the umbilical artery as determined by continuous-wave Doppler ultrasound was investigated. Of the 51 pregnancies recruited, six were complicated by pre-eclampsia, 10 by intrauterine growth retardation, 15 by both pre-eclampsia and fetal growth retardation, and there were 20 controls. A significant correlation was demonstrated between both plasma viscosity and gestational age and the resistance index used to characterize the Doppler waveform. Multiple regression analysis demonstrated that changes in plasma viscosity explained 55% of the variance seen in the resistance index and that this was statistically significant. This finding is, however, unlikely to be of clinical significance as whole blood viscosity had an insignificant effect on the impedance in the umbilical artery. We postulate that vascular factors such as the number and calibre of the placental arterioles are a more important determinant of umbilical artery impedance.

Effects of preparative procedures and of cell activation on flow of white cells through micropore filters

Using newly developed filtration techniques to analyse the flow resistance of white blood cells (WBC), the effects of preparative procedures and of various treatments (including activation) have been tested. Flow rates of WBC were measured using both 5 and 8 micron pore filters. It was found that EDTA was the anticoagulant of choice over heparin and sodium citrate, and that calcium-containing media should be avoided because they promoted cell-cell aggregation. Exposure to density separation media did not significantly alter filtration rates, but storage of prepared WBC for even 1 h caused deterioration in flow. Storage of whole blood before preparation of the WBC had a much lesser effect. Storage appeared to be linked to cell activation, and use of the activating agents phorbol ester (PE, 4.5 x 10(6) M/l) and f-methyl-leucyl-phenylalanine (FMPL, 10(-7) and 10(-9) M/l) also increased WBC resistance to pore transit. The effect of PE was greater, causing rapid pore blockage, but was non-specific, while the lesser effect of FMLP was restricted to granulocytes and was concentration dependent. Cell volume was increased by these agents, but measurement of the filterability of hypotonically swollen granulocytes showed that volume changes alone only partly explained the activation effects. These results suggest that activation in vivo would have a significant rheological effect, detectable by filtration methods.

Maternal blood viscosity and uteroplacental blood flow velocity waveforms in normal and complicated pregnancies

According to the Poiseuille-Hagen law, viscosity influences flow resistance. A possible effect of blood viscosity upon the resistance index of the uteroplacental circulation as measured by continuous wave Doppler ultrasound was investigated in 50 pregnant women. It was found that blood viscosity variables explained only about 10% of the variation in the resistance index in all patients, which was not statistically significant. It is suggested, therefore, that the vascular contribution to flow resistance may be more important.