Association of Circulating Platelet Extracellular Vesicles and Pulse Wave Velocity with Cardiovascular Risk Estimation.

Elevated circulating platelet-derived extracellular vesicles (EVs) have been reported in conditions associated with thrombotic risk. The present study aimed to assess the relationship between circulating platelet-derived EV levels, cardiovascular risk stratification and vascular organ damage, as assessed by pulse wave velocity (PWV). A total of 92 patients were included in the present analysis. Platelet EV were evaluated by flow cytometry (CD41+/Annexin v+). The cardiovascular risk was determined using the 2021 ESC guideline stratification and SCORE2 and SCORE-OP. PWV was performed as a surrogate to assess macrovascular damage. Risk stratification revealed significant group differences in EV levels (ANOVA, p = 0.04). Post hoc analysis demonstrated significantly higher levels of EVs in the very high-risk group compared with the young participants (12.53 ± 8.69 vs. 7.51 ± 4.67 EV/µL, p = 0.03). Linear regression models showed SCORE2 and SCORE-OP (p = 0.04) was a predictor of EV levels. EVs showed a significant association with macrovascular organ damage measured by PWV (p = 0.01). PWV progressively increased with more severe cardiovascular risk (p < 0.001) and was also associated with SCORE2 and SCORE-OP (p < 0.001). Within the pooled group of subjects with low to moderate risk and young participants (<40 years), those with EV levels in the highest tertile had a trend towards higher nocturnal blood pressure levels, fasting glucose concentration, lipid levels, homocysteine and PWV. Levels of platelet-derived EVs were highest in those patients with very high CV risk. Within a pooled group of patients with low to moderate risk, an unfavourable cardiometabolic profile was present with higher EV levels.

Circulating short-chain fatty acids in hypertension: a reflection of various hypertensive phenotypes.

BACKGROUND: Hypertension is the most common chronic condition globally, contributing to an increased risk of cardiovascular disease and premature death. Despite advances in treatment options, approximately 10% of patients have resistant hypertension, characterized by elevated blood pressure that does not respond to treatment. The gut microbiome is now increasingly recognized to play a role in the development and pathogenesis of several diseases, including hypertension, although the exact mechanisms remain unclear. METHOD: The aim of the present study was to investigate circulating levels of short-chain fatty acids, metabolites produced by gut bacteria, in essential ( n  = 168) and resistant hypertensive ( n  = 27) patients, compared with healthy controls ( n  = 38). RESULTS: Serum acetate was significantly lower in the resistant hypertensive population, compared with both the normotensive controls and those with essential hypertension (748 ±â€Š89 versus 1335 ±â€Š61 and 1171 ±â€Š22 nmol/ml, P  < 0.0001). Acetate was also significantly lower in treated versus untreated hypertensive patients or controls (1112 ±â€Š27 versus 1228 ±â€Š40 and 1327 ±â€Š63 nmol/l, P  < 0.01), with this finding more pronounced with increasing number of antihypertensive therapies. In contrast, propionate was lower and butyrate significantly higher in those with essential hypertension compared with controls (propionate: 25.2 ±â€Š7.5 versus 58.6 ±â€Š7.6 nmol/ml, P  < 0.0001; butyrate: 46.5 ±â€Š3.5 versus 14.7 ±â€Š9.9 nmol/ml, P  < 0.01). A novel and perhaps clinically relevant observation was the significant difference in acetate and propionate levels between patients taking ACE inhibitors or angiotensin-receptor blockers. CONCLUSION: The present study has highlighted differences in circulating short-chain fatty acids in different hypertensive phenotypes and a possible influence of drug number and class. Although further research is necessary, this may represent a novel therapeutic target, particularly in patients with resistant hypertension.

Circulating platelet-derived extracellular vesicles correlate with night-time blood pressure and vascular organ damage and may represent an integrative biomarker of vascular health.

Elevated office blood pressure (BP) has previously been associated with increased levels of circulating extracellular vesicles (EVs). The present study aimed to assess the relationship between levels of platelet derived EVs, ambulatory BP parameters, and pulse wave velocity as a marker of macrovascular organ damage. A total of 96 participants were included in the study. Platelet-derived extracellular vesicles (pEVs) were evaluated by flow cytometry (CD41+/Annexin v+). BP evaluation included unobserved automated office BP and ambulatory BP monitoring. Carotid-femoral pulse wave velocity (PWV) was measured as a marker of macrovascular damage. pEVs correlated with nocturnal systolic BP (r = 0.31; p = .003) and nocturnal dipping (r = -0.29; p = .01) in univariable analysis. Multivariable regression models confirmed robustness of the association of EVs and nocturnal blood pressure (p = .02). In contrast, systolic office, 24h- and daytime-BP did not show significant associations with pEVs. No correlations were found with diastolic BP. Circulating pEVs correlated with pulse wave velocity (r = 0.25; p = .02). When comparing different hypertensive phenotypes, higher levels of EVs and PWV were evident in patients with sustained hypertension compared to patients with white coat HTN and healthy persons. Circulating platelet derived EVs were associated with nocturnal BP, dipping, and PWV. Given that average nocturnal BP is the strongest predictor of CV events, platelet derived EVs may serve as an integrative marker of vascular health, a proposition that requires testing in prospective clinical trials.

Retinal Capillary Damage Is Already Evident in Patients With Hypertension and Prediabetes and Associated With HbA1c Levels in the Nondiabetic Range.

OBJECTIVE: We analyzed whether any change in capillary density in the retinal circulation could be detected in patients with hypertension in the prediabetic stage. RESEARCH DESIGN AND METHODS: In a cross-sectional analysis, we assessed capillary density in the foveal (CDF) and parafoveal retinal areas using optical coherence tomography-angiography in 62 patients with hypertension and normal glucose metabolism and 40 patients with hypertension and prediabetes. RESULTS: The CDF was lower in patients with prediabetes than in those with normal glucose metabolism. Moreover, we found a correlation between CDF and HbA1c and glucose levels for the entire cohort. In patients with HbA1c <6.5% (48 mmol/mol), CDF was lower in patients with HOMA for insulin resistance (HOMA-IR) ≥2.5 than in patients with HOMA-IR <2.5. CONCLUSIONS: Patients with hypertension and prediabetes display retinal capillary changes, and an association with markers of glucose metabolism exists, even within a nondiabetic HbA1c range.

Autoencoded deep features for semi-automatic, weakly supervised physiological signal labelling.

BACKGROUND AND AIMS: Machine Learning is transforming data processing in medical research and clinical practice. Missing data labels are a common limitation to training Machine Learning models. To overcome missing labels in a large dataset of microneurography recordings, a novel autoencoder based semi-supervised, iterative group-labelling methodology was developed. METHODS: Autoencoders were systematically optimised to extract features from a dataset of 478621 signal excerpts from human microneurography recordings. Selected features were clusters with k-means and randomly selected representations of the corresponding original signals labelled as valid or non-valid muscle sympathetic nerve activity (MSNA) bursts in an iterative, purifying procedure by an expert rater. A deep neural network was trained based on the fully labelled dataset. RESULTS: Three autoencoders, two based on fully connected neural networks and one based on convolutional neural network, were chosen for feature learning. Iterative clustering followed by labelling of complete clusters resulted in all 478621 signal peak excerpts being labelled as valid or non-valid within 13 iterations. Neural networks trained with the labelled dataset achieved, in a cross validation step with a testing dataset not included in training, on average 93.13% accuracy and 91% area under the receiver operating curve (AUC ROC). DISCUSSION: The described labelling procedure enabled efficient labelling of a large dataset of physiological signal based on expert ratings. The procedure based on autoencoders may be broadly applicable to a wide range of datasets without labels that require expert input and may be utilised for Machine Learning applications if weak-labels were available.

Simultaneously measured inter-arm blood pressure difference is not associated with pulse wave velocity in a clinical dataset of at-risk hypertensive patients.

Recent analysis of systolic inter-arm differences in blood pressure from the INTERPRESS-IPD Collaboration suggest an association with increased all-cause mortality, cardiovascular mortality and cardiovascular events. Previous studies have demonstrated associations with other risk parameters. We aimed to reproduce these associations in a cohort of 199 treated, at-risk hypertensive patients with pulse wave velocity (PWV) as a surrogate marker of cardiovascular (CV) damage. Simultaneously measured inter-arm blood pressure (BP) differences, 24 hour ambulatory BP and PWV were measured in 199 treated patients from a tertiary hospital hypertension outpatient clinic. Associations between systolic inter-arm BP difference and PWV were analyzed with uni- and multi-variate regression models. Out of 199 participants, 90 showed an inter-arm BP difference of more than 5 mmHg. The inter-arm difference was not associated with PWV. Furthermore, neither observed single BP measurements nor 24 hour ambulatory BP was associated with inter-arm BP differences. In our clinical patient cohort we failed to observe an association between inter-arm BP differences and PWV. Mode of assessment, study design and the sample characteristics of this treated, hypertensive cohort may have contributed to the negative findings. The limited sample size of the study poses a challenge to the detection of smaller effects in our study.

A standarized protocol for evaluation of large extracellular vesicles using the attune™ NXT system.

Extracellular vesicles (EVs) represent a promising biomarker in several medical areas. Flow cytometry (FC) is one of the most widely-used methods to characterize EVs, providing quantitative information and determination of EV subtypes. EV evaluation represents a challenge as no standardized methods are available to facilitate assessment across different research centers. This is principally because their size falls below the detection limit of most standard flow cytometers and a thorough optimization process is required to ensure instrument-specific sensitivity. We provide an overview of a standardized method to evaluate large EVs using the Attune™ Nxt Acoustic Focusing Flow Cytometer system (Thermo Fisher Scientific).

Homocysteine predicts vascular target organ damage in hypertension and may serve as guidance for first-line antihypertensive therapy.

Homocysteine is an independent risk factor for cardiovascular and cerebrovascular disease and has been proposed to contribute to vascular dysfunction. We sought to determine in a real-world clinical setting whether homocysteine levels were associated with hypertension mediated organ damage (HMOD) and could guide treatment choices in hypertension. We performed a cross-sectional analysis of prospectively collected data in 145 hypertensive patients referred to our tertiary hypertension clinic at Royal Perth Hospital and analyzed the association of homocysteine with HMOD, renin-angiotensin-aldosterone system (RAAS), and RAAS blockade. The average age of participants was 56 ± 17 years, and there was a greater proportion of males than females (89 vs. 56). Regression analysis showed that homocysteine was significantly associated with PWV (ß = 1.99; 95% CI 0.99-3.0; p < .001), albumin-creatinine ratio (lnACR: ß = 1.14; 95% CI 0.47, 1.8; p < .001), 24 h urinary protein excretion (ß = 0.7; 95% CI 0.48, 0.92; p < .001), and estimated glomerular filtration rate (ß = -29.4; 95% CI -36.35, -22.4; p < .001), which persisted after adjusting for potential confounders such as age, sex, 24 h BP, inflammation, smoking, diabetes mellitus (DM), and dyslipidemia. A positive predictive relationship was observed between plasma homocysteine levels and PWV, with every 1.0 µmol/L increase in homocysteine associated with a 0.1 m/s increase in PWV. Homocysteine was significantly associated with elevated aldosterone concentration (ß = 0.26; p < .001), and with attenuation of ACEi mediated systolic BP lowering and regression of HMOD compared to angiotensin receptor blockers in higher physiological ranges of homocysteine. Our results indicate that homocysteine is associated with hypertension mediated vascular damage and could potentially serve to guide first-line antihypertensive therapy.