The chronic stress risk phenotype mirrored in the human retina as a neurodegenerative condition.

The brain is the key organ that orchestrates the stress response which translates to the retina. The retina is an extension of the brain and retinal symptoms in subjects with neurodegenerative diseases substantiated the eye as a window to the brain. The retina is used in this study to determine whether chronic stress reflects neurodegenerative signs indicative of neurodegenerative conditions. A three-year prospective cohort (n = 333; aged 46 ± 9 years) was stratified into stress-phenotype cases (n = 212) and controls (n = 121) by applying the Malan stress-phenotype index. Neurodegenerative risk markers included ischemia (astrocytic S100 calcium-binding protein B/S100B); 24-h blood pressure, proteomics; inflammation (tumor-necrosis-factor-α/TNF-α); neuronal damage (neuron-specific-enolase); anti-apoptosis of retinal-ganglion-cells (beta-nerve-growth-factor), astrocytic activity (glial-fibrillary-acidic-protein); hematocrit (viscosity) and retinal follow-up data [vessels; stress-optic-neuropathy]. Stress-optic-neuropathy risk was calculated from two indices: a newly derived diastolic-ocular-perfusion-pressure cut-point ≥68 mmHg relating to the stress-phenotype; combined with an established cup-to-disk ratio cut-point ≥0.3. Higher stress-optic-neuropathy (39% vs. 17%) and hypertension (73% vs. 16%) prevalence was observed in the stress-phenotype cases vs. controls. Elevated diastolic-ocular-perfusion-pressure, indicating hypoperfusion, was related to arterial narrowing and trend for ischemia increases in the stress-phenotype. Ischemia in the stress-phenotype at baseline, follow-up and three-year changes was related to consistent inflammation (TNF-α and cytokine-interleukin-17-receptor-A), neuron-specific-enolase increases, consistent apoptosis (chitinase-3-like protein 1, low beta-nerve-growth-factor), glial-fibrillary-acidic-protein decreases, elevated viscosity, vein widening as risk marker of endothelial dysfunction in the blood-retinal barrier, lower vein count, and elevated stress-optic-neuropathy. The stress-phenotype and related neurodegenerative signs of ongoing brain ischemia, apoptosis and endothelial dysfunction compromised blood-retinal barrier permeability and optic nerve integrity. In fact, the stress-phenotype could identify persons at high risk of neurodegeneration to indicate a neurodegenerative condition.

Glial cell activity in cardiovascular diseases and risk of acute myocardial infarction.

Growing evidence indicates that the pathophysiological link between the brain and heart underlies cardiovascular diseases, specifically acute myocardial infarction (AMI). Astrocytes are the most abundant glial cells in the central nervous system and provide support/protection for neurons. Astrocytes and peripheral glial cells are emerging as key modulators of the brain-heart axis in AMI, by affecting sympathetic nervous system activity (centrally and peripherally). This review, therefore, aimed to gain an improved understanding of glial cell activity and AMI risk. This includes discussions on the potential role of contributing factors in AMI risk, i.e., autonomic nervous system dysfunction, glial-neurotrophic and ischemic risk markers [glial cell line-derived neurotrophic factor (GDNF), astrocytic S100 calcium-binding protein B (S100B), silent myocardial ischemia, and cardiac troponin T (cTnT)]. Consideration of glial cell activity and related contributing factors in certain brain-heart disorders, namely, blood-brain barrier dysfunction, myocardial ischemia, and chronic psychological stress, may improve our understanding regarding the pathological role that glial dysfunction can play in the development/onset of AMI. Here, findings demonstrated perturbations in glial cell activity and contributing factors (especially sympathetic activity). Moreover, emerging AMI risk included sympathovagal imbalance, low GDNF levels reflecting prothrombic risk, hypertension, and increased ischemia due to perfusion deficits (indicated by S100B and cTnT levels). Such perturbations impacted blood-barrier function and perfusion that were exacerbated during psychological stress. Thus, greater insights and consideration regarding such biomarkers may help drive future studies investigating brain-heart axis pathologies to gain a deeper understanding of astrocytic glial cell contributions and unlock potential novel therapies for AMI.

Stress-induced cardiac troponin T, S100B and estradiol responses in defensive copers: The SABPA study.

Ineffective stress-coping in Africans is associated with cardiac ischemia during acute mental stress. Ischemic conditions may be worsened by stress-induced release of glial-derived S100­calcium-binding-protein ß (S100B), which is pro-apoptotic for cardiomyocytes. Whether estradiol as coping regulator and cardio-protective factor will protect against pro-apoptotic effects, remains unclear. Therefore, we aimed to investigate stress-induced associations between cardiac troponin T/cTnT (cardiac ischemic marker), S100B and estradiol in a bi-ethnic cohort of defensive copers of both sexes. The target population study included African and Caucasian teachers of both sexes (n = 344; aged 20-65 years). The Stroop-color-word-conflict-test was administrated for 1 min to induce acute mental stress in the participants. A chronic stress risk phenotype score was obtained. The Coping Strategy Indicator determined habitual defensive/avoidance/seeking social support coping scores. Fasting blood samples were obtained prior to and 10 min post-Stroop-stress to assess cTnT, S100B and estradiol levels. An interaction between ethnicity, sex and defensive coping (p < 0.05) was found for acute stress-induced percentage changes in estradiol. In defensive coping African men, the Stroop-color-word-conflict-test elicited decreases in S100B and increases in estradiol. Again, in this group, S100B decreases were related to unchanged cTnT, a chronic stress risk phenotype and acute estradiol increases (p < 0.05). No associations among main markers were apparent in the African women or the Caucasian defensive copers of both sexes. In the defensive coping African men, the markers studied may play a relevant role in the brain-cardiovascular system interaction during stress exposure. Further research is needed to elaborate on potential mechanisms and to establish clinical relevance.

The Role of Physical Activity Status in the Relationship between Obesity and Carotid Intima-Media Thickness (CIMT) in Urban South African Teachers: The SABPA Study.

Globally, the prevalence of physical inactivity and obesity are on the rise, which may increase carotid intima-media thickness (CIMT) as a marker of subclinical atherosclerosis. This study assessed the association between physical activity (PA), obesity, and CIMT. A cross-sectional study design was used, including a sub-sample (n = 216) of teachers who participated in the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SAPBA) study. Measurements included the following: physical activity status (measured with ActiHeart devices over 7 consecutive days), body mass index (BMI), waist circumference (WC), waist-to-height ratio (WtHR), CIMT (measured by SonoSite Micromax ultrasound), blood pressure (BP), fasting C-reactive protein (CRP), and cholesterol and glucose levels. Data were analysed using the Statistical Package for Social Science. One-third of the teachers were physically inactive (33%) and had low-grade inflammation CRP ≥ 3 mg/L (41%). Males were more sedentary and had higher BP and CIMT (p < 0.05). Independent of age and sex, WC or central obesity was 2.63 times more likely (p = 0.02) to contribute to atherosclerosis, especially in females (OR: 4.23, p = 0.04). PA levels were insignificantly and negatively (ß −0.034; 0.888; 0.240) related to subclinical atherosclerosis. The cardiovascular disease risk profiles and limited PA status may have curbed the beneficial impact of PA on the obesity and atherosclerosis.

Associations of conscientiousness with cardiac troponin T and stress coping responses in a teacher cohort: the SABPA prospective cohort study.

BACKGROUND: In a South African bi-ethnic cohort, defensive (DefS)/social support/avoidance coping strategies have been shown to influence cardiac troponin T (cTnT) levels through different stress signalling pathways. Personality traits (extraversion, neuroticism, conscientiousness, openness to experience, agreeableness) partially control stress coping responses and may affect prospective cardiac responses. Hence in this cohort, we aimed to examine relationships between personality traits and coping strategies, and to assess associations between cTnT changes over time, personality traits and coping strategies. METHODS: A cohort of African and Caucasian male and female teachers (n = 359) participating in both phases of the Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) study, was prospectively followed for three years. Personality traits (Basic Traits Inventory) and coping (Coping Strategy Indicator) scores were determined. Fasting serum samples for cTnT determination were collected. Established hypertension-related cTnT cut-off points of 4.2 pg/ml (Africans) and 5.6 pg/ml (Caucasians) were applied. RESULTS: Higher neuroticism and lower conscientiousness scores were found in the Africans than in the Caucasians (p < 0.05). Both traits correlated with all three coping strategies in Caucasians, but only with DefS and avoidance coping in Africans. Over a period of three years, cTnT levels decreased in both races. Compared to Africans, Caucasians showed a greater recovery from the ethnic-specific cTnT cut-off point over time. In the Africans with high DefS scores, cTnT level changes were inversely associated with conscientiousness (adjusted R2 = 0.14; ß = -0.26). In Caucasians scoring high in avoidance coping, conscientiousness (odds ratio 0.84) and neuroticism (odds ratio 0.90) showed a lower likelihood of predicting the cTnT cut-off point. CONCLUSION: In both races, conscientiousness may contribute to healthier stress coping responses and protect against cardiac ischaemia and risk of hypertension.

Exploring biomarkers associated with deteriorating vascular health using a targeted proteomics chip: The SABPA study.

ABSTRACT: In this observational study, by the use of a multiplex proteomic platform, we aimed to explore associations between 92 targeted proteins involved in cardiovascular disease and/or inflammation, and phenotypes of deteriorating vascular health, with regards to ethnicity.Proteomic profiling (92 proteins) was carried out in 362 participants from the Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) study of black and white African school teachers (mean age 44.7 ±â€Š9.9 years, 51.9% women, 44.5% Black Africans, 9.9% with known cardiovascular disease). Three proteins with <15% of samples below detectable limits were excluded from analyses. Associations between multiple proteins and prevalence of hypertension as well as vascular health [Carotid intima-media thickness (cIMT) and pulse wave velocity (PWV)] measures were explored using Bonferroni-corrected regression models.Bonferroni-corrected significant associations between 89 proteins and vascular health markers were further adjusted for clinically relevant co-variates. Hypertension was associated with growth differentiation factor 15 (GDF-15) and C-X-C motif chemokine 16 (CXCL16). cIMT was associated with carboxypeptidase A1 (CPA1), C-C motif chemokine 15 (CCL15), chitinase-3-like protein 1 (CHI3L1), scavenger receptor cysteine-rich type 1 protein M130 (CD163) and osteoprotegerin, whereas PWV was associated with GDF15, E-selectin, CPA1, fatty acid-binding protein 4 (FABP4), CXCL16, carboxypeptidase B (CPB1), and tissue-type plasminogen activator. Upon entering ethnicity into the models, the associations between PWV and CPA1, CPB1, GDF-15, FABP4, CXCL16, and between cIMT and CCL-15, remained significant.Using a multiplex proteomic approach, we linked phenotypes of vascular health with several proteins. Novel associations were found between hypertension, PWV or cIMT and proteins linked to inflammatory response, chemotaxis, coagulation or proteolysis. Further, we could reveal whether the associations were ethnicity-dependent or not.

Correction: Relationship between physical activity and carotid intima-media thickness among teachers in South Africa: the SABPA study.

In the Abstract, in Methods: Ultrasound CIMT imaging was done using the SonoSite Micromaxx. Physical activity was done over seven consecutive days. In the Abstract, in Results: The prevalence of obesity according to BMI and sedentary behaviour was above 30%; hypertension was 38.9% and low-grade inflammation (CRP) was 41.1%.

A Stress Syndrome Prototype Reflects Type 3 Diabetes and Ischemic Stroke Risk: The SABPA Study.

Type 3 diabetes (T3D) accurately reflects that dementia, e.g., Alzheimer's disease, represents insulin resistance and neurodegeneration in the brain. Similar retinal microvascular changes were observed in Alzheimer's and chronic stressed individuals. Hence, we aimed to show that chronic stress relates to T3D dementia signs and retinopathy, ultimately comprising a Stress syndrome prototype reflecting risk for T3D and stroke. A chronic stress and stroke risk phenotype (Stressed) score, independent of age, race or gender, was applied to stratify participants (N = 264; aged 44 ± 9 years) into high stress risk (Stressed, N = 159) and low stress risk (non-Stressed, N = 105) groups. We determined insulin resistance using the homeostatic model assessment (HOMA-IR), which is interchangeable with T3D, and dementia risk markers (cognitive executive functioning (cognitiveexe-func); telomere length; waist circumference (WC), neuronal glia injury; neuron-specific enolase/NSE, S100B). Retinopathy was determined in the mydriatic eye. The Stressed group had greater incidence of HOMA-IR in the upper quartile (≥5), larger WC, poorer cognitiveexe-func control, shorter telomeres, consistently raised neuronal glia injury, fewer retinal arteries, narrower arteries, wider veins and a larger optic cup/disc ratio (C/D) compared to the non-Stressed group. Furthermore, of the stroke risk markers, arterial narrowing was related to glaucoma risk with a greater C/D, whilst retinal vein widening was related to HOMA-IR, poor cognitiveexe-func control and neuronal glia injury (Adjusted R2 0.30; p ≤ 0.05). These associations were not evident in the non-Stressed group. Logistic regression associations between the Stressed phenotype and four dementia risk markers (cognitiveexe-func, telomere length, NSE and WC) comprised a Stress syndrome prototype (area under the curve 0.80; sensitivity/specificity 85%/58%; p ≤ 0.001). The Stress syndrome prototype reflected risk for HOMA-IR (odds ratio (OR) 7.72) and retinal glia ischemia (OR 1.27) and vein widening (OR 1.03). The Stressed phenotype was associated with neuronal glia injury and retinal ischemia, potentiating glaucoma risk. The detrimental effect of chronic stress exemplified a Stress syndrome prototype reflecting risk for type 3 diabetes, neurodegeneration and ischemic stroke.

Circulating neurotrophins and hemostatic risk factors of atherothrombotic cardiovascular disease at baseline and during sympathetic challenge: the SABPA study.

Sympathetic activation may trigger acute coronary syndromes. We examined the relation between circulating neurotrophic factors and hemostatic risk factors of atherothrombotic cardiovascular disease at baseline and in response to acute mental stress to establish a brain-heart link. In 409 black and white South Africans, brain-derived neurotrophic factor (BDNF) and fibrinolytic measures were assessed at baseline. Glial cell-derived neurotrophic factor (GDNF), S100 calcium-binding protein (S100B), von Willebrand factor (VWF), fibrinogen and D-dimer were assessed at baseline and 10 min after the Stroop test. Neurotrophins were regressed on hemostatic measures adjusting for demographics, comorbidities, cardiometabolic factors and health behaviors. Higher baseline BDNF was associated with greater stress-induced increase in fibrinogen (p = 0.003) and lower D-dimer increase (p = 0.016). Higher baseline S100B was significantly associated with higher baseline VWF (p = 0.031) and lower fibrinogen increase (p = 0.048). Lower baseline GDNF was associated with higher baseline VWF (p = 0.035) but lower VWF increase (p = 0.001). Greater GDNF (p = 0.006) and S100B (p = 0.042) increases were associated with lower VWF increase. All associations showed small-to-moderate effect sizes. Neurotrophins and fibrinolytic factors showed no significant associations. The findings support the existence of a peripheral neurothrophin-hemostasis interaction of small-to-moderate clinical relevance. The implications for atherothrombotic cardiovascular disease need further exploration.

Delayed retinal vein recovery responses indicate both non-adaptation to stress as well as increased risk for stroke: the SABPA study.

OBJECTIVES: Low or high sympatho-adrenal-medullary axis (SAM) and hypothalamic-pituitary-adrenal axis (HPA) dysregulation reflect chronic stress. Retinal vessel dynamics may relate to SAM, HPA activity and stroke risk. Our objectives were therefore to assess the relationships between retinal vessel, SAM and HPA responses, and to determine stroke risk. METHODS: A prospective bi-ethnic gender cohort (n = 275, 45 ± 9 years) was included. Urine/serum/saliva samples for SAM [norepinephrine:creatinine ratio (u-NE)] and HPA [adrenocorticotrophic hormone (ACTH), cortisol] were obtained at baseline, three-year follow up and upon flicker light-induced provocation. Diastolic ocular perfusion pressure was measured as a marker of hypo-perfusion. Retinal arterial narrowing and venous widening calibres were quantified from digital images in the mydriatic eye. A validated stress and stroke risk score was applied. RESULTS: An interaction term was fitted for venous dilation in u-NE tertiles (p ≤ 0.05) and not in u-NE median/quartiles/quintiles. Independent of race or gender, tertile 1 (low u-NE) had a 112% increase in u-NE, decreases in cortisol, and no changes in ACTH over three years (positive feedback). Tertile 3 (high u-NE) contradictorily had decreases in u-NE and cortisol, and increases in ACTH (negative feedback). In tertile 1, reduced arterial dilation, and faster arterial vasoconstriction and narrowing were related to higher SAM activity and hypo-perfusion (p ≤ 0.05), whereas delayed venous dilation, recovery and widening were related to cortisol hypo-secretion (p ≤ 0.05). In tertile 1, delayed venous recovery responses predicted stress and stroke risk [odds ratio 4.8 (1.2-19.6); p = 0.03]. These associations were not found in u-NE tertiles 2 and 3. CONCLUSIONS: In response to low norepinephrine, a reflex increase in SAM activity occurred, enhancing arterial vasoconstriction and hypo-perfusion. Concomitant HPA dysregulation attenuated retinal vein vasoactivity and tone, reflecting delayed vein recovery responses and non-adaptation to stress. These constrained vein recovery responses are indicative of increased chronic stress and stroke risk.

NT-proBNP and metabolic risk factors in a bi-ethnic cohort: the Ambulatory Blood Pressure in African prospective cohort study.

BACKGROUND: We explored the association of N-terminal probrain natriuretic peptide (NT-proBNP) with metabolic traits in a bi-ethnic African-Caucasian cohort. METHODS: Baseline examinations of the Sympathetic activity and Ambulatory Blood Pressure in African (SABPA) prospective cohort study were performed between 2008 and 2009, and re-examination after a three-year follow up in South African teachers (black African, n = 194; Caucasian, n = 203). RESULTS: Each one standard deviation increment of NT-proBNP was significantly inversely associated with body mass index ( ß -1.01), glycated haemoglobin ( ß -0.14 %), waist circumference (ß -1.82), HOMA-IR (ß -0.47), insulin (ß -1.66) and triglyceride levels (ß -0.04). Each one standard deviation increment of NT-proBNP was also associated with reduced odds of incident diabetes, and subjects within the highest quartile of NT-proBNP were at lowest risk (OR: 0.24; 95% CI: 0.06-0.96; p = 0.041). CONCLUSIONS: In the SABPA cohort, Africans and Caucasians had similar NT-proBNP levels; however, the associations for Africans were stronger. Those findings suggest that BNP may affect the propensity for metabolic disturbances differently in Africans and Caucasians.

Relationship between physical activity and carotid intima-media thickness among teachers in South Africa: the SABPA study.

OBJECTIVE: To determine the relationship between objectively measured physical activity (PA) and carotid intima-media thickness (CIMT) in teachers in South Africa. METHODS: A cross-sectional study was conducted among 215 teachers aged 25 to 65 years (mean age 49.67 ± 8.43 years) who participated in the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) prospective cohort study. CIMT was measured using the SonoSite Micromaxx ultrasound over seven consecutive days. Other measurements obtained included body mass index (BMI), waist circumference, 24-hour ambulatory blood pressure, and C-reactive protein (CRP) and fasting blood total cholesterol levels. Data were analysed using Statistical Package for Social Sciences (SPSS) version 25. RESULTS: The prevalence of obesity according to BMI and sedentary behaviour was above 30%; hypertension was 38.9% and CRP 41.1 mg/dl. Male teachers showed higher mean values for CIMT than female teachers (0.75 ± 0.16 vs 0.66 ± 0.12 mm; p ≤ 0.05). A borderline negative association existed between CIMT and mean seven-day awake metabolic equivalent of task (r = -0.19; p = 0.08) in female teachers in the light-PA group. CIMT was inversely associated with total energy expenditure (r = -0.31; p = 0.05) in sedentary male teachers. CONCLUSIONS: Participation in light PA was associated with lower CIMT values in female teachers. Given the health implications of cardiovascular disease risk among teachers, PA intervention studies are recommended to determine effective interventions to provide information on how to decrease the progression of subclinical atherosclerosis in this population.

Heart rate variability, the dynamic nature of the retinal microvasculature and cardiac stress: providing insight into the brain-retina-heart link: the SABPA study.

BACKGROUND AND AIMS: Decreased heart-rate-variability (HRV) indicates increased sympathetic nervous system (SNS) activity and modulation with a shift in the sympatho-vagal balance towards SNS predominance. Increased SNS activity may precede volume-loading hypertension, contribute to increases in cardiac troponin T (cTnT), endothelial dysfunction and small vessel disease. Therefore, we investigated the retinal vasculature, HRV during flicker-light-induced-provocation (FLIP) and systemic cTnT, a marker of cardiac stress, to provide further evidence in support of the brain-retina-heart link. METHODS: Cross-sectional observations were obtained from a bi-ethnic cohort (N = 264), aged 23-68 years. Fasting serum samples for cTnT were obtained. Retinal vascular calibres were quantified from mydriatic eye fundus images and dynamic retinal vessel calibre responses were determined during FLIP. Time-and frequency domain parameters of HRV were calculated during FLIP for each participant. RESULTS: Africans had wider venules and attenuated time domain parameters during FLIP. In Africans, inverse associations emerged between arteriolar dilation and both cTnT and root-mean squared of the standard deviations of successive RR-intervals (rMSSD) (p = 0.030), and between arteriolar constriction and both low-frequency expressed in normalised units (LFnu) (p = 0.003) and high-frequency expressed in normalised units (p = 0.021). Wider venules inversely associated with standard deviation of the NN intervals (SDNN) as well as LFnu (p = 0.009) in Africans. An opposite profile was observed in Caucasians with both time-and frequency domain parameters of HRV in relation to retinal vessel structure and function. CONCLUSION: FLIP elicited increased SNS activity and modulation in this bi-ethnic cohort. In Africans, decreased HRV during FLIP accompanied arteriolar and venular responses and elevated systemic levels of cTnT, implying that the SNS exerted a significant effect on the smooth muscle tone of the retinal vasculature. Disrupted retinal autoregulation may imply general autonomic nervous system dysfunction; exemplifying central control by the brain on all systemic regulatory functions, across different vascular beds.

Relation of the renin-angiotensin-aldosterone system with potential cardiac injury and remodelling: the SABPA study.

Purpose: The renin-angiotensin-aldosterone system (RAAS) plays an important role in maintaining hemodynamic homeostasis. Ethnic disparities exist regarding RAAS activity due to sympathetic activity and sodium-water retention, however the implications thereof on cardiac damage is unknown. This study investigated the associations of cardiac troponin T (cTnT), N-terminal pro-brain natriuretic peptide (NTproBNP) and subclinical LVH with components of the RAAS (renin, aldosterone and aldosterone-to-renin ratio (ARR)) and copeptin in a black and white South African cohort.Materials and methods: The study population consisted of 305 participants (black = 139, white = 166) aged 20-62 years. Serum cTnT, NTproBNP, Cornell product, components of the RAAS (active renin, aldosterone and ARR) and copeptin were determined.Results: The black group had lower renin (p < 0.001) and higher ARR (p < 0.001), cTnT (p = 0.015) and Cornell product compared to whites (all p < 0.001). NTproBNP and copeptin were similar between the groups. After forward stepwise adjustments for multiple confounders, inverse associations of cTnT with renin (ß = -0.17, p = 0.018) and aldosterone (ß = -0.14, p = 0.048) as well as an inverse association between NTproBNP and aldosterone (ß = -0.25, p < 0.001) were observed in the white population only. In the black group cTnT associated positively with renin (ß = 0.16, p = 0.040) and copeptin (ß = 0.21, p = 0.020) and inversely with ARR (ß = -0.15, p = 0.047). Additionally, NTproBNP associated positively with copeptin (ß = 0.18, p = 0.045). No correlations were observed between the RAAS and Cornell product in any of the groups.Conclusions: Our findings suggest that RAAS, together with cardiac stress may function differently in cardiac damage and remodelling in the two ethnic groups; which may influence treatment in clinical practice.

Ambulatory blood pressure monitoring and morning surge in blood pressure in adult black and white South Africans.

We examined whether there were differences in the circadian variation in blood pressure and the morning surge in blood pressure between black and white Africans. Clinic and ambulatory blood pressure data obtained from the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study was examined (n = 406; 49% black African). Ambulatory blood pressure readings were fitted to a six-parameter double logistic equation to determine the power and rate of the morning surge in blood pressure. Multiple linear regression analysis was used to examine differences in blood pressure between black and white participants. Clinic and ambulatory blood pressure were higher in black participants throughout the day and night. In those taking medications, blood pressure was less well controlled in black subjects. Despite the higher systolic blood pressure, the day-night difference estimated by the logistic function was similar in black and white participants. However, the rate of rise and power in the morning surge in blood pressure was lower in black participants. We conclude that black participants of the SABPA study present with higher blood pressure throughout the day and night but have a lower power of the morning surge in blood pressure due to a slower morning rate of increase. Moreover, they had an increased prevalence of undiagnosed hypertension and, in those taking medication, were less likely to have their blood pressure controlled than their white counterparts.

Correction to: Heart rate variability, the dynamic nature of the retinal microvasculature and cardiac stress: providing insight into the brain-retina-heart link: the SABPA study.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A primary aldosteronism-like phenotype identified with the aldosterone-to-angiotensin II ratio in black men: the SABPA study.

INTRODUCTION: Black populations may be more likely to have primary aldosteronism (PA) due to adrenal hyperplasia or other forms of adrenal hyperactivity, with suppressed renin levels and high levels of aldosterone, which may contribute to the development of hypertension. METHODS: This sub-study involved 35 black men matched for age, gender and race, and aged 20-65 years, living in the North West Province of South Africa. RAAS triple-A analysis was carried out with LC-MS/MS quantification. Blood pressure, electrocardiography and other variables were determined with known methods. RESULTS: Hypertensive subjects with higher aldosterone levels showed an increased aldosterone-angiotensin II ratio (AA2 ratio) compared to the hypertensive subjects with low aldosterone levels (10.2 vs 3.0 pmol/l; p = 0.003). The serum potassium concentration was significantly lower in the high-aldosterone group and the serum sodium-potassium ratio was significantly higher compared to the low-aldosterone group (3.9 vs 4.5, p = 0.016, 34.8 vs 31.8, p = 0.032, respectively). Furthermore, aldosterone was positively associated with both left ventricular hypertrophy (Cornell product) (Spearman R = 0.560; p = 0.037) and kidney function [albumin-to-creatinine ratio (ACR) ] (Spearman R = 0.589, p = 0.021) in the hypertensive high-serum aldosterone group. CONCLUSIONS: The AA2 ratio, a novel screening test that is currently being validated for PA case detection, was used to identify a PA-like phenotype in black men. Excess aldosterone was associated with endothelial dysfunction and left ventricular hypertrophy, independent of blood pressure.

Retinal-glia ischemia and inflammation induced by chronic stress: The SABPA study.

Background: Psychobiological processes linking stress and vascular diseases remain poorly understood. The retina and the brain share a common embryonic-diencephalon origin and blood-barrier physiology e.g. ongoing ischemia facilitates S100B release with astrocytic activity and glial-fibrillary-acidic-protein expression (GFAP). However, GFAP decreases revealed astrocyte pathology in the prefrontal cortex of depression/suicide cases; and might be a key mechanism in stress - disease pathways. Methods: A chronic emotional stress phenotype independent of age, ethnicity or sex was used to stratify the current prospective cohort (N â€‹= â€‹359; aged 46 â€‹± â€‹9 years) into Stress (N â€‹= â€‹236) and no-Stress groups (N â€‹= â€‹123). Prospective data for glia ischemia risk markers were obtained, including 24 â€‹h BP, fasting S100B, GFAP, HbA1C and tumor-necrosis-factor-α (TNF-α). At 3-yr follow-up: diastolic-ocular-perfusion-pressure (indicating hypo-perfusion risk) was measured and retinal vessel calibers were quantified from digital images in the mydriatic eye. Results: Higher hypertension (75% vs. 16%), diabetes (13% vs. 0%) and retinopathy (57% vs. 45%) prevalence was observed in Stress compared to no-Stress individuals. Stressed individuals had consistently raised S100B, TNF-α, HbA1C and higher diastolic-ocular-perfusion-pressure, but decreases in GFAP and GFAP:S100B. Furthermore stroke risk markers, arterial narrowing and venous widening were associated with consistently raised S100B, GFAP:S100B (p â€‹= â€‹0.060), TNF-α and higher diastolic-ocular-perfusion-pressure [Adj. R2 0.39-0.41, p â€‹≤ â€‹0.05]. No retinal-glia associations were evident in the no-Stress group. Conclusions: Retinal-glia ischemia and inflammation was induced by chronic stress. Persistent higher inflammation and S100B with GFAP decreases further reflected stress-induced astrocyte pathology in the human retina. It is recommended to increase awareness on chronic stress and susceptibility for brain ischemia.

A primary aldosteronism-like phenotype identified with the aldosterone-to-angiotensin II ratio in black men: the SABPA study

Introduction:Black populations may be more likely to have primary aldosteronism (PA) due to adrenal hyperplasia orother forms of adrenal hyperactivity, with suppressed renin levels and high levels of aldosterone, which may contribute to the development of hypertension.Methods:This sub-study involved 35 black men matched for age, gender and race, and aged 20­65 years, living in the North West Province of South Africa. RAAS triple-A analysis was carried out with LC-MS/MS quantification. Blood pressure, electrocardiography and other variables were deter -mined with known methods.Results:Hypertensive subjects with higher aldosterone levels showed an increased aldosterone­angiotensin II ratio (AA2ratio) compared to the hypertensive subjects with low aldos-terone levels (10.2 vs 3.0 pmol/l;p= 0.003). The serum potassium concentration was significantly lower in the high-aldosterone group and the serum sodium­potassium ratio was significantly higher compared to the low-aldosterone group(3.9 vs 4.5,p= 0.016, 34.8 vs 31.8,p= 0.032, respectively).Furthermore, aldosterone was positively associated with both left ventricular hypertrophy (Cornell product) (SpearmanR=0.560;p= 0.037) and kidney function [albumin-to-creatinineratio (ACR)] (SpearmanR= 0.589,p= 0.021) in the hyper-tensive high-serum aldosterone group Conclusions:The AA2 ratio, a novel screening test that is currently being validated for PA case detection, was used toidentify a PA-like phenotype in black men. Excess aldosterone was associated with endothelial dysfunction and left ventricu-lar hypertrophy, independent of blood pressure

Copeptin relates to a fatty liver and measures of obesity in a South African population with mixed ethnicities.

PURPOSE: Elevated copeptin, a vasopressin marker, is linked to metabolic disease, and obese rats with low-vasopressin concentration had a decreased risk of liver steatosis. We here investigated the association between copeptin and nonalcoholic fatty liver disease (NAFLD) and possible differences in copeptin concentration between ethnicities. METHODS: In this cross-sectional study of 361 South Africans (n = 172 African black, 189 = Caucasian) with a mean age of 45 years and 45% men, plasma copeptin was measured and associated with NAFLD according to a validated fatty liver index accounting for measures of BMI, waist, triglycerides, and gamma-glutamyltransferase. RESULTS: There was no significant difference in copeptin concentrations between ethnicities after age and gender adjustment (p = 0.24). Increasing copeptin tertile levels were significantly associated with obesity, overweight, and abdominal obesity, respectively, after multivariate adjustment for age, gender, ethnicity, and high HOMA-IR (p = 0.02 for all). Individuals in the second and third copeptin tertile had an increased odds (95% CI) of NAFLD of 1.77 (1.04-3.02) and 2.97 (1.74-5.06), respectively, compared to the bottom tertile (p < 0.001). The association between increasing copeptin tertile and NAFLD remained significant after adjustment for age, gender, ethnicity, high HOMA-IR, self-reported current alcohol intake, and statin treatment (p = 0.01). CONCLUSIONS: Elevated plasma copeptin is independently associated with NAFLD in a population with mixed ethnicities, pointing at the pharmacologically modifiable vasopressin system as a new mechanism behind NAFLD.