Microbial Interventions to Control and Reduce Blood Pressure in Australia (MICRoBIA): rationale and design of a double-blinded randomised cross-over placebo controlled trial

Background: Hypertension is a prevalent chronic disease worldwide that remains poorly controlled. Recent studies support the concept that the gut microbiota is involved in the development of hypertension and that dietary fibre intake may act through the gut microbiota to lower blood pressure (BP). Resistant starch is a type of prebiotic fibre which is metabolised by commensal bacteria in the colon to produce short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate. Previous work in pre-clinical models provides strong evidence that both prebiotic fibre as well as SCFAs (i.e. postbiotics) can prevent the development of hypertension. The aim of this clinical trial is to determine if acetylated and butyrylated modified resistant starch can decrease BP of hypertensive individuals via the modulation of the gut microbiota and release of high levels of SCFAs.Methods: This is a phase IIa double-blinded, randomised, cross-over, placebo controlled trial. Participants are randomly allocated to receive either a diet containing 40 g/day of the modified resistant starch or placebo (corn starch or regular flour) for 3 weeks on each diet, with a 3-week washout period between the two diets. BP is measured in the office, at home, and using a 24-h ambulatory device. Arterial stiffness is measured using carotid-to-femoral pulse wave velocity. Our primary endpoint is a reduction in ambulatory daytime systolic BP. Secondary endpoints include changes to circulating cytokines, immune markers, and modulation to the gut microbiome.Discussion: The findings of this study will provide the first evidence for the use of a combination of pre- and postbiotics to lower BP in humans. The results are expected at the end of 2021

Association of hearing impairment with incident depressive symptoms: a community-based prospective study

Objective: The aim was to investigate the potential association between hearing impairment and incident depressive symptoms.Methods: Using a prospective community-based cohort study in France (the Paris Prospective Study III), participants aged 50-75 years were recruited between 2008 and 2012 and thereafter followed up every 2 years up to 2018. Hearing impairment, measured at study recruitment by audiometry testing, was defined as a pure tone average >25 decibels in the better ear. Incident depressive symptoms, measured using the validated 13-item Questionnaire of Depression 2nd version, was assessed during follow-up. Multivariate generalized estimating equations were used to compute odds ratio (OR) and 95% confidence intervals (CI).Results: Among 7591 participants free of depressive symptoms at baseline (mean age 59.8 years, 63% of men), 14.3% had hearing impairment. Over 6 years of follow-up, 479 subjects (6.3%) had incident depressive symptoms. The OR for incident depressive symptoms was 1.36 for subjects with baseline hearing impairment (95% CI, 1.06-1.73). A pooled analysis of 4 published prospective studies yielded a multivariable relative risk of baseline hearing impairment for incident depressive symptoms of 1.29 (95% CI, 1.09-1.53).Conclusions: In this community-based prospective cohort study of participants aged 50 to 75 years, baseline hearing impairment was associated with a 36% increased odds of incident depressive symptoms

Carotid artery stiffness and incident depressive symptoms: The Paris Prospective Study III

Background: Arterial stiffness may contribute to late-life depression via cerebral microvascular damage, but evidence is scarce. No longitudinal study has evaluated the association between arterial stiffness and risk of depressive symptoms. Therefore, we investigated the association between carotid artery stiffness and incident depressive symptoms in a large community-based cohort study.Methods: This longitudinal study included 7013 participants (mean age 59.7 ± 6.3 years; 35.8% women) free of depressive symptoms at baseline. Carotid artery stiffness (high-resolution echo tracking) was determined at baseline. Presence of depressive symptoms was determined at baseline and at 4 and 6 years of follow-up, and was defined as a score ≥7 on the validated Questionnaire of Depression, Second Version, Abridged and/or new use of antidepressant medication. Logistic regression and generalized estimating equations were used.Results: In total, 6.9% (n = 484) of the participants had incident depressive symptoms. Individuals in the lowest tertile of carotid distensibility coefficient (indicating greater carotid artery stiffness) compared with those in the highest tertile had a higher risk of incident depressive symptoms (odds ratio: 1.43; 95% confidence interval: 1.10-1.87), after adjustment for age, sex, living alone, education, lifestyle, cardiovascular risk factors, and baseline Questionnaire of Depression, Second Version, Abridged scores. Results were qualitatively similar when we used carotid Young's elastic modulus as a measure of carotid stiffness instead of carotid distensibility coefficient, and when we used generalized estimating equations instead of logistic regression.Conclusions: Greater carotid stiffness is associated with a higher incidence of depressive symptoms. This supports the hypothesis that carotid stiffness may contribute to the development of late-life depression

Body silhouette trajectories across the lifespan and vascular aging: The Paris Prospective Study 3

Vascular aging is a major contributor to cardiovascular disease and can be quantified by higher carotid stiffness, intima-media thickness and diameter, and hypertension. Weight gain across the lifetime may be an important, modifiable determinant of vascular aging. We therefore aimed to assess lifetime body silhouette trajectories (a marker of weight change across the lifespan) in relation to vascular aging in late adulthood. We used cross-sectional data from a community-based cohort study (n=8243; age, 59.4; 38.7% women). A linear mixed model was used to assess trajectories of recalled body silhouettes from age 8 to 45 years. We assessed carotid artery properties (ultrasonography), resting hypertension (blood pressure ≥140/90 mm Hg or use of antihypertensives), and exaggerated exercise blood pressure, a marker of masked hypertension (systolic blood pressure ≥150 mm Hg during submaximal exercise) at study recruitment when the participants were 50 to 75 years of age. We identified 5 distinct body silhouette trajectories: lean stable (32.0%), lean increase (11.1%), moderate stable (32.5%), lean-marked increase (16.3%), and heavy stable (8.1%). Compared with individuals in the lean-stable trajectory, those in the moderate-stable, lean-marked increase, and heavy-stable trajectories had higher carotid stiffness, intima-media thickness and diameter (odds ratios between 1.23 and 2.10 for highest quartile versus lowest quartile of manifestations of vascular aging; PP<0.05). Vascular aging was most prominent among individuals who were lean in early life but markedly gained weight during young adulthood and among those who were heavy in early life and maintained weight

The Ultrasound Window Into Vascular Ageing: A Technology Review by the VascAgeNet COST Action

Non-invasive ultrasound (US) imaging enables the assessment of the properties of superficial blood vessels. Various modes can be used for vascular characteristics analysis, ranging from radiofrequency (RF) data, Doppler- and standard B/M-mode imaging, to more recent ultra-high frequency and ultrafast techniques. The aim of the present work was to provide an overview of the current state-of-the-art non-invasive US technologies and corresponding vascular ageing characteristics from a technological perspective. Following an introduction about the basic concepts of the US technique, the characteristics considered in this review are clustered into: 1) vessel wall structure; 2) dynamic elastic properties, and 3) reactive vessel properties. The overview shows that ultrasound is a versatile, non-invasive, and safe imaging technique that can be adopted for obtaining information about function, structure, and reactivity in superficial arteries. The most suitable setting for a specific application must be selected according to spatial and temporal resolution requirements. The usefulness of standardization in the validation process and performance metric adoption emerges. Computer-based techniques should always be preferred to manual measures, as long as the algorithms and learning procedures are transparent and well described, and the performance leads to better results. Identification of a minimal clinically important difference is a crucial point for drawing conclusions regarding robustness of the techniques and for the translation into practice of any biomarker