Retinal Vessel Functional Responses in South Africans Living With and Without HIV: The EndoAfrica-NWU Study.

OBJECTIVES: The effects of HIV and antiretroviral therapy (ART) on microvascular function are poorly explored. We compared retinal vessel functional responses to flicker light-induced provocation (FLIP) in people living with HIV (PLWH) and people living without HIV (PLWoutH). METHODS: We included 115 PLWH and 51 PLWoutH with a median age of 41 years. Treated PLWH received similar first-line fixed-dose combination ART. Clinical characteristics and retinal vessels functional responses to FLIP were compared in (a) PLWH and PLWoutH; and (b) PLWH groups stratified by the median of (i) CD4-count (511 cells/mm3), (ii) viral load (50 copies/mL), and (iii) ART duration (57.6 months). RESULTS: PLWH were older, smoked more, and had a lower prevalence of hypertension than PLWoutH (p < 0.05). Almost 64% of PLWH were infected for more than 5 years. Retinal vessel responses to FLIP were similar between PLWH and PLWoutH after taking confounders into account. In addition, PLWH subgroups stratified according to immuno-virological status by CD4-count, viral load, and ART duration showed no differences in retinal vessel responses to FLIP. CONCLUSION: Living with HIV and receiving ART were not associated with altered microvascular function as assessed with dynamic retinal vessel analysis in a South African case-control study.

Food intake in South African children and retinal microvascular health: The ExAMIN Youth SA study.

BACKGROUND AND AIMS: Retinal arteriolar narrowing and venular widening are associated with increased cardiovascular risk, even at young ages. Whether diet contributes to early microvascular changes in children is not widely explored. We explored the associations of frequency of healthy and unhealthy food group intake with retinal vessel calibers in black and white children. METHODS AND RESULTS: This study included school-aged (5-9 years) black (N = 433, 7.46 ± 0.98 years), and white (N = 403, 7.43 ± 0.82 years) children. Anthropometric and blood pressure measurements were taken, along with retinal vessel calibers (central retinal arteriolar (CRAE) and venular (CRVE) equivalents). Frequencies of food group intake were assessed using a food-frequency questionnaire. A factor analysis was performed to describe food group patters. Independent associations between retinal vessel calibers and frequencies of food group intake and food group patters were explored. In black children, cookies, cakes, and biscuits were associated with narrower arterioles (p < 0.05). In white children, cold sweetened beverages were associated with narrower arterioles (p = 0.02), whereas salty snacks were associated with narrower arterioles (p = 0.01) and wider venules (p < 0.05). Fruits were positively associated with CRAE (p = 0.03) in white children only. CONCLUSION: A higher frequency of unhealthy food group consumption was associated with retinal arteriolar narrowing and venular widening in both black and white children. However, fruit intake was shown beneficial for retinal microvascular health in white children only. Our findings may highlight the importance of promoting healthy eating patterns from early childhood which may reduce the risk of premature cardiovascular disease development.

To Airbnb or not to Airbnb: Does Airbnb feel safer than hotels during a pandemic?

Airbnb was able to recover faster than hotels from the downturn caused by the COVID-19 pandemic. This research note examines whether Airbnb's success resulted from tourists feeling safer in Airbnbs due to their greater opportunities for social distancing. Nearly 9500 U.S. adults were surveyed between March 2020 and July 2021, and asked the degree to which they would be concerned about staying in a hotel or Airbnb, within the context of the pandemic. Very similar levels of concern were associated with both lodging types, even as this concern decreased as the pandemic unfolded. The similar levels of concern towards hotels and Airbnbs suggest that other factors better explain Airbnb's comparatively rapid recovery from the pandemic. Implications and suggestions for future research are discussed.

Obesity, hypertension, and tobacco use associated with left ventricular remodeling and hypertrophy in South African women: Birth to Twenty Plus Cohort.

BACKGROUND: Left ventricular hypertrophy (LVH) is a marker of increased risk in developing future life-threatening cardiovascular disease (CVD), however, it is unclear how CVD risk factors, such as obesity, blood pressure (BP), and tobacco use, are associated with left ventricular (LV) remodeling and LVH in urban African populations. Therefore, we aimed to identify the prevalence of LVH as well as the health factors associated with LV remodeling and LVH, within black South African adult women and their pre-pubescent children. METHODS: Black female adults (n = 123; age: 29-68 years) and their children (n = 64; age: 4-10; 55% female) were recruited from the Birth to Twenty Plus Cohort in Soweto, South Africa. Tobacco and alcohol use, physical activity, presence of diabetes mellitus, heart disease, and medication were self-reported. Height, weight, and blood pressure were measured in triplicate to determine the prevalence of obesity and hypertension respectively. Echocardiography was used to assess LV mass at end-diastole, based on linear measurements, and indexed to body surface area to determine LVH. RESULTS: Hypertension and obesity prevalences were 35.8% and 59.3% for adults and 45.3% and 6.3% for children. Self-reported tobacco use in adults was 22.8%. LVH prevalence was 35.8% in adults (75% eccentric: 25% concentric), and 6.3% in children. Concentric remodeling was observed in 15.4% of adults, however, concentric remodeling was only found in one child. In adults, obesity [OR: 2.54 (1.07-6.02; p = 0.02)] and hypertension [3.39 (1.08-10.62; p = 0.04)] significantly increased the odds of LVH, specifically eccentric LVH, while concentric LVH was associated with self-reported tobacco use [OR: 4.58 (1.18-17.73; p = 0.03)]. Although no logistic regression was run within children, of the four children LVH, three had elevated blood pressure and the child with normal blood pressure was overweight. CONCLUSIONS: The association between obesity, hypertension, tobacco use, and LVH in adults, and the 6% prevalence of LVH in children, calls for stronger public health efforts to control risk factors and monitor children who are at risk.

Determining Underlying Mechanisms of Early Vascular Ageing by Clustered Analysis: The African-PREDICT Study.

OBJECTIVE: Identifying individuals at increased risk of early vascular ageing (EVA) is paramount to inform intervention and prevention strategies and curb the increasing burden of cardiovascular disease. METHODS: We stratified and phenotyped pre-screened young apparently healthy South African adults (20-30 yrs) (n=1,041) into vascular ageing profile groups based on carotid femoral pulse wave velocity (cfPWV) percentiles (healthy vascular ageing [HVA]; average vascular ageing [AVA] and EVA). We further compared various anthropometric, cardiovascular (CV), oxidative stress and lifestyle risk factors and determined factor scores to explore associations between CV measures and factor clusters to explore associations in those at risk of EVA. RESULTS: Young adults in the EVA group displayed marked phenotypic characteristics in terms of anthropometry, CV, and lifestyle risk factors, even though cfPWV were within healthy ranges. Blood pressure (brachial and central) and cfPWV were all incrementally higher across all three vascular ageing groups (p-trend ≤0.011). Hypertension, lifestyle risk factors such as self-reported smoking and alcohol consumption were all highest in the EVA group (p-trend ≤0.046). Additionally, in the EVA group only, cfPWV (adj. R2=0.028; ß=0.171; p=0.042) associated positively with Factor 2 (oxidative stress and antioxidant capacity). No associations existed between Factor 1 (basic lipids) and any anthropometric or CV measures (p>0.050). CONCLUSION: Young adults with higher cfPWV presented with a less favourable vascular profile and more unhealthy lifestyle behaviours compared to groups with lower cfPWV. In the EVA group, cfPWV positively associated with a cluster of oxidative stress and antioxidant capacity. Early lifestyle behaviours may have the ability to modify the balance between oxidants and antioxidants, potentially contributing to early onset arterial stiffness.

Socioeconomic inequalities, modifiable lifestyle risk factors, and retinal vessel calibers: The African-PREDICT Study.

OBJECTIVE: Lifestyle risk factors vary between socioeconomic status (SES) groups and may influence cardiovascular function differently. The retinal microvasculature allows for monitoring early changes in cardiovascular health, and therefore, we investigated whether retinal vessel calibers associate differently with modifiable risk factors in different SES groups. METHODS: We included 1064 young adults (aged 20-30 years) grouped by low and high SES. The central retinal artery and vein equivalents (CRAE, CRVE) were determined from fundus images captured using the Dynamic Retinal Vessel Analyzer (Imedos Systems GmbH, Jena, Germany). We collected anthropometry, self-reported alcohol consumption, and biochemical data. RESULTS: Retinal vessel calibers did not differ between SES groups (p ≥ .80) after adjusting for sex and ethnicity. Unique independent associations were observed in the low SES group, where CRAE (ß = 0.08, p = .042) and CRVE (ß = .14, p = .001) associated positively with cotinine and body mass index, respectively. In the high SES group, CRAE (ß = -0.09, p = .027) associated negatively with alcohol consumption. CONCLUSION: At young ages, retinal vessel calibers associated differently with modifiable lifestyle risk factors within each SES group. Our data highlight the importance of detecting adverse lifestyle risk factors among young adults from diverse socioeconomic settings to improve prevention of cardiovascular disease.

Retinal vasodilatory responses are inversely associated with plasminogen activator inhibitor-1: The African-PREDICT study.

AIMS: Plasminogen activator inhibitor-1 (PAI-1), traditionally associated with fibrinolysis, is increasingly implicated in impaired vascular function. However, studies on its association with microvascular function are limited to the cutaneous and coronary microvascular beds in older and diseased individuals. To better understand its potential involvement in the early stages of disease development, we investigated the associations of retinal vasodilatory responses to flicker light with PAI-1 activity (PAI-1act) in young and healthy individuals. METHODS: We included healthy Black and White women and men (n = 518; aged 20-30 years), and measured plasma PAI-1act and retinal vasodilatory responses to flicker light provocation. We also collected demographic and lifestyle data, measured blood pressure, anthropometry, blood lipids, inflammatory and other biomarkers. RESULTS: In multivariate regression analyses, maximal retinal venular dilation associated independently and inversely with PAI-1act (adj. R2 = 0.11; ß = -0.15; p = 0.001) in the total group. In exploratory subgroup analyses, this association remained in White women (adj. R2 = 0.07; ß = -0.23; p = 0.005), and was more robust with younger age and lower blood pressure and in non-smokers, but also with greater central adiposity, higher low-density lipoprotein cholesterol and inflammation (all p < 0.05). CONCLUSIONS: Our data suggest that in young individuals, PAI-1 may already be associated with subclinical microvascular dysfunction.

Potassium excretion and blood pressure are associated with heart rate variability in healthy black adults: The African-PREDICT study.

BACKGROUND AND AIMS: Heart rate variability (HRV) is a main determinant of autonomic function and related to the development of hypertension and cardiovascular (CV) disease. Hypertension develops in black populations at an earlier age, which could be due to differences in the autonomic nervous system activity and sodium/potassium handling in black and white populations. We investigated whether HRV is associated with 24 h urinary sodium and potassium excretion and blood pressure (BP) in a young bi-ethnic cohort. METHODS AND RESULTS: We examined 423 black and 483 white healthy adults (aged 24.5 ± 3.1 years) for 24 h HRV, including standard deviation of normal RR intervals (SDNN) reflecting autonomic variations over time, and root mean square of successive differences (RMSSD) reflecting parasympathetic activity. We measured 24 h urinary sodium and potassium concentration and BP. The black group had lower SDNN and potassium excretion as well as higher RMSSD, sodium and Na/k ratio compared to the white group (all p < 0.05). Only in black individuals, urinary potassium excretion was independently and negatively associated with SDNN (ß[95% CI];-0.26[-0.50;-0.02]ms) and RMSSD (-0.14[-0.27;-0.01]ms, p < 0.05). One unit increase in sodium/potassium (Na/K) ratio was associated with higher SDNN (ß[95% CI]; 3.04[0.89; 5.19]ms) and RMSSD (1.60[0.41; 2.78]ms) in the black cohort only (both p < 0.001). In both groups elevated 24 h diastolic BP was associated with lower RMSSD (p < 0.05). CONCLUSION: Lower potassium excretion and higher Na/K ratio related independently to higher HRV in young and healthy black adults. A better ethnic-specific understanding of sodium and potassium handling is required as part of preventive cardiology, especially in black individuals. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03292094; URL: https://clinicaltrials.gov/ct2/show/NCT03292094.

Von Willebrand factor, its cleaving protease (ADAMTS13), and inflammation in young adults: The African-PREDICT study.

BACKGROUND: The role of inflammation in the early development of vascular dysfunction remains complex. Interleukin-6 (IL-6) and C-reactive protein (CRP) can cause an acute imbalance in the von Willebrand factor (vWF)-ADAMTS13 interaction, indicating a possible link between markers of haemostasis and low-grade inflammation. To better understand these inter-relationships in the early phases of disease development, we investigated whether vWF and ADAMTS13 associate with the pro-inflammatory markers, IL-6 and CRP in healthy young adults. We considered the role of blood types, sex and race on these relationships. METHODS: In healthy black and white men and women (n = 1113; 24 ± 5 years; no previous diagnosis or medication use for chronic diseases) we analysed von Willebrand factor antigen (vWFag), ADAMTS13, IL-6 and CRP, and grouped blood types as non-O (A, B and AB) and O. Covariates included socioeconomic status, age, estimated glomerular filtration rate, 24-hour systolic blood pressure, waist circumference, glucose, total cholesterol, platelet count, γ-glutamyl transferase and total energy expenditure. RESULTS: In the total group, vWFag was highest in the third tertile of both IL-6 and CRP (p ≤ 0.014), while ADAMTS13 was lowest in the third compared to the first IL-6 tertile (p = 0.006). In multivariate regression, vWFag associated positively with IL-6 (Adj R2 = 0.169; ß = 0.123; p = 0.001) and CRP (Adj R2 = 0.163; ß=0.094; p = 0.019) in the total group, in the O blood group (all p ≤ 0.051) and white men (all p ≤ 0.035). ADAMTS13 associated negatively with IL-6 (Adj R2 = 0.053; ß = -0.154; p = 0.015) and CRP (Adj R2 = 0.055; ß = -0.177; p = 0.009), only in the O blood group. CONCLUSIONS: Markers of haemostasis associated independently with low-grade inflammation in the O type blood group and white men. An interplay between the haemostatic and inflammatory systems may already exist in young healthy adults and is dependent on blood groups, sex and race. This extends our understanding on the role of inflammation in the early development of vascular dysfunction prior to cardiovascular compromise.

Retinal vessel caliber and caliber responses in true normotensive black and white adults: The African-PREDICT study.

PURPOSE: Globally, a detrimental shift in cardiovascular disease risk factors and a higher mortality level are reported in some black populations. The retinal microvasculature provides early insight into the pathogenesis of systemic vascular diseases, but it is unclear whether retinal vessel calibers and acute retinal vessel functional responses differ between young healthy black and white adults. METHODS: We included 112 black and 143 white healthy normotensive adults (20-30 years). Retinal vessel calibers (central retinal artery and vein equivalent (CRAE and CRVE)) were calculated from retinal images and vessel caliber responses to flicker light induced provocation (FLIP) were determined. Additionally, ambulatory blood pressure (BP), anthropometry and blood samples were collected. RESULTS: The groups displayed similar 24 h BP profiles and anthropometry (all p > .24). Black participants demonstrated a smaller CRAE (158 ±â€¯11 vs. 164 ±â€¯11 MU, p < .001) compared to the white group, whereas CRVE was similar (p = .57). In response to FLIP, artery maximal dilation was greater in the black vs. white group (5.6 ±â€¯2.1 vs. 3.3 ±â€¯1.8%; p < .001). CONCLUSIONS: Already at a young age, healthy black adults showed narrower retinal arteries relative to the white population. Follow-up studies are underway to show if this will be related to increased risk for hypertension development. The reason for the larger vessel dilation responses to FLIP in the black population is unclear and warrants further investigation.

Vascular function and cardiovascular risk in a HIV infected and HIV free cohort of African ancestry: baseline profile, rationale and methods of the longitudinal EndoAfrica-NWU study.

BACKGROUND: People living with the Human Immunodeficiency Virus (PLHIV) have an increased susceptibility to develop non-communicable diseases such as cardiovascular disease (CVD). Infection with HIV contributes to the development of CVD independent of traditional risk factors, with endothelial dysfunction being the central physiological mechanism. While HIV-related mortality is declining due to antiretroviral treatment (ART), the number of deaths due to CVD is rising in South Africa - the country with the highest number of PLHIV and the world's largest ART programme. The EndoAfrica study was developed to determine whether HIV infection and ART are associated with cardiovascular risk markers and changes in vascular structure and function over 18 months in adults from different provinces of South Africa. This paper describes the rationale, methodology and baseline cohort profile of the EndoAfrica study conducted in the North West Province, South Africa. METHODS: In this case-control study, conducted between August 2017 and June 2018, 382 volunteers of African descent (276 women; 106 men), comprising of 278 HIV infected and 104 HIV free individuals were included. We measured health behaviours, a detailed cardiovascular profile, and performed biomarker analyses. We compared baseline characteristics, blood pressure, vascular function and biochemical markers between those infected and HIV free. RESULTS: At baseline, the HIV infected participants were older (43 vs 39 years), less were employed (21% vs 40%), less had a tertiary education (7% vs 16%) and their body mass index was lower (26 vs 29 kg/m2) than that of the HIV free participants. While the cardiovascular profile, flow-mediated dilation and pulse wave velocity did not differ, glycated haemoglobin was lower (p = 0.017) and total cholesterol, high density lipoprotein cholesterol, triglycerides, gamma-glutamyltransferase and tobacco use were higher (all p < 0.047) in PLHIV. CONCLUSION: Despite PLHIV being older, preliminary cross-sectional analysis suggests that PLHIV being treated with ART do not have poorer endothelial or vascular function compared to the HIV free participants. More detailed analyses on the baseline and follow-up data will provide further clarity regarding the cardiovascular profile of South Africans living with HIV.

Autonomic activity and its relationship with the endogenous cardiotonic steroid marinobufagenin: the African-PREDICT study.

Aim: Marinobufagenin (MBG), a cardiotonic steroid and a natriuretic hormone, is elevated in response to high salt diet consumption. In animal models salt intake stimulates adrenocortical MBG secretion via increased angiotensin II, sympathetic activity and aldosterone. No evidence in humans exists to suggest the involvement of the angiotensinergic-sympatho-excitatory pathway in MBG production. We investigated whether MBG is related to indices of autonomic activity in men and women. Methods: This cross-sectional study included 680 black and white, men and women from the African-PREDICT study (aged 20-30 years). Continuous 24 hr ECG recordings were used to obtain low and high frequency (LF, HF) heart rate variability (HRV). We measured 24 hr urinary MBG excretion and serum aldosterone. Results: We found a positive association of MBG excretion with estimated salt intake (P < 0.001) and aldosterone (P < 0.001) in women and men. In women only, a positive relationship was evident between MBG excretion and LF HRV in multivariate adjusted regression analyses (Adj. R 2 = 0.33; ß = 0.11; P = 0.030). In men, MBG excretion associated positively with HF HRV in similar regression analyses (R 2 = 0.36; ß = 0.12; P = 0.034). Sex-specific results were corroborated only in blacks, namely, a positive association of MBG excretion with LF HRV in black women (R 2 = 0.38; ß = 0.13; P = 0.036), and negative association with HF HRV in black men (R 2 = 0.40; ß = 0.18; P = 0.045). No relationships were evident in white women (P = 0.58) or men (P = 0.27). Conclusion: Our findings in this human cohort support suggested mechanisms whereby MBG is elevated as a result of increased salt intake, including autonomic activity, previously demonstrated in Dahl salt-sensitive hypertension.

How an electronic health record became a real-world research resource: comparison between London's Whole Systems Integrated Care database and the Clinical Practice Research Datalink.

BACKGROUND: In the UK, several initiatives have resulted in the creation of local data warehouses of electronic patient records. Originally developed for commissioning and direct patient care, they are potentially useful for research, but little is known about them outside their home area. We describe one such local warehouse, the Whole Systems Integrated Care (WSIC) database in NW London, and its potential for research as the "Discover" platform. We compare Discover with the Clinical Practice Research Datalink (CPRD), a popular UK research database also based on linked primary care records. METHODS: We describe the key features of the Discover database, including scope, architecture and governance; descriptive analyses compare the population demographics and chronic disease prevalences with those in CPRD. RESULTS: As of June 2019, Discover held records for a total of 2.3 million currently registered patients, or 95% of the NW London population; CPRD held records for over 11 million. The Discover population matches the overall age-sex distribution of the UK and CPRD but is more ethnically diverse. Most Discover chronic disease prevalences were comparable to the national rates. Unlike CPRD, Discover has identifiable care organisations and postcodes, allowing mapping and linkage to healthcare provider variables such as staffing, and includes contacts with social, community and mental health care. Discover also includes a consent-to-contact register of over 3000 volunteers to date for prospective studies. CONCLUSIONS: Like CPRD, Discover has been a number of years in the making, is a valuable research tool, and can serve as a model for other areas developing similar data warehouses.

Leptin and the Retinal Microvasculature in Young Black and White Adults: The African-PREDICT Study.

BACKGROUND: Leptin is a vasoactive peptide that has been linked to diseases associated with macrovascular deterioration. What is still uncertain is its involvement in the microvasculature. Since microvascular changes are presumed to precede macrovascular deterioration, we examined whether measures of the retinal microvasculature are associated with leptin in healthy, young Black and White individuals. METHOD: We included 283 Black and 289 White men and women (aged 20-30 years). We determined serum leptin, calculated central retinal artery and vein equivalents and arterio-venous ratio. We also measured retinal vessel responses to light flicker provocation. RESULTS: Black men were leaner and had lower leptin than White men, whereas Black women had increased adiposity and leptin compared to White women (all p<0.001). Black groups had narrower retinal arteries, and greater maximum arteriolar and venular dilations in response to light flicker than the White groups (p<0.001). Arterio-venous ratio associated negatively with leptin (all p≤0.044) in all groups (except Black women), but was lost upon adjustment for body mass index and other covariates. We found an inverse association between maximal venular dilation and leptin only in Black men in single and multiple regression analyses (Std ß= -0.22; R2=0.05; p=0.035). No associations were found between other retinal measures with leptin in the other groups. CONCLUSION: We found an independent, negative association between retinal vein dilation with leptin in healthy, young Black men, suggesting a potential detrimental role for leptin in regulating microvascular responses in a population group known to be at greater risk of cardiovascular disease development.

Leptin and the vasculature in young adults: The African-PREDICT study.

BACKGROUND AND AIM: Information regarding the effect of leptin on the vasculature in young healthy adults at risk for cardiovascular disease development is limited. We therefore examined the associations between measures of subclinical atherosclerosis (carotid intima-media thickness, carotid cross-sectional wall area), large artery stiffness (pulse wave velocity) and a measure of endothelial dysfunction (von Willebrand factor [vWF]) with leptin in young healthy men and women. METHODS: In a cross-sectional study in South Africa involving 820 normotensive individuals (337 men and 483 women) aged 20-30 years, we measured carotid intima-media thickness, carotid cross-sectional wall area, pulse wave velocity, vWF from citrated plasma and leptin from serum. RESULTS: Despite sevenfold higher leptin in women than men (P < 0.001), only in young healthy men, we observed negative, independent associations between measures of carotid wall thickness (carotid intima-media thickness: R2  = 0.05; ß = -0.20; P = 0.036; carotid cross-sectional wall area: R2  = 0.05; ß = -0.20; P = 0.035) with leptin in multivariable-adjusted regression analyses. When reviewing these associations across body mass index categories, we found an association to be evident only in overweight men (carotid intima-media thickness: R2  = 0.15; ß = -0.41; P = 0.007; carotid cross-sectional wall area: R2  = 0.21; ß = -0.47; P = 0.002). No association was observed in the women or between pulse wave velocity and vWF with leptin. CONCLUSION: In young healthy men, we found a beneficial inverse association between measures of carotid wall thickness and circulating leptin, thereby supporting a potential vascular protective role of leptin.

The Association of Measures of the Micro- and Macro-Vasculature with Selenium and GPx Activity in a Young Bi-Ethnic Population: The African-PREDICT Study.

Objective: Selenium plays an important physiological role as component for antioxidant selenoproteins such as glutathione peroxidase (GPx). Since oxidative stress contributes to hypertension development, it is likely that selenium deficiency may contribute to the burden of cardiovascular disease. To better understand the involvement of selenium and GPx in the early development of cardiovascular disease, we investigated in young, healthy black and white African men and women whether measures of the micro- and macrovasculature are related to selenium and GPx activity. Methods: In young adults (N = 394; aged 20-30 years) we determined serum selenium, GPx activity, microvascular measures (central retinal artery equivalent, central retinal vein equivalent, arteriolar-to-venular ratio [AVR], and estimated glomerular filtration rate [eGFR]), and macrovascular measures (pulse wave velocity, 24-hour pulse pressure [PP] and augmentation index [Aix]). Results: In multivariable-adjusted regression analyses, there were vasculoprotective associations between serum selenium and a microvascular measure (AVR [ß = 0.23; p = 0.036]) in black African women and with a macrovascular measure (24-hour PP [ß = -0.15; p = 0.048]) in white African women. In turn, GPx activity also showed a protective association with a microvascular measure (eGFR) in white African men (ß = 0.23; p = 0.035), as well as with macrovascular measures (AIx, PP) in the black (ß = -0.25; p = 0.027) and white African men (ß = -0.22; p = 0.035), and black African women (ß = -0.32; p = 0.001). Conclusions: Collectively the findings suggest a protective role for the micronutrient selenium and GPx on both the micro- and macrovasculature in a young, healthy bi-ethnic population.

The Na+K+-ATPase Inhibitor Marinobufagenin and Early Cardiovascular Risk in Humans: a Review of Recent Evidence.

PURPOSE OF REVIEW: This review synthesizes recent findings in humans pertaining to the relationships between marinobufagenin (MBG), a steroidal Na+/K+-ATPase inhibitor and salt-sensitivity biomarker, and early cardiovascular risk markers. RECENT FINDINGS: Twenty-four-hour urinary MBG strongly associates with habitual salt intake in young healthy adults (aged 20-30 years). Furthermore, in young healthy adults free of detected cardiovascular disease, MBG associates with increased large artery stiffness and left ventricular mass independent of blood pressure. These findings in human studies corroborate mechanistic data from rat studies whereby stimulation of MBG by a high salt intake or MBG infusion increased vascular fibrosis and cardiac hypertrophy. Twenty-four-hour urinary MBG may be a potential biomarker of early cardiovascular risk. Adverse associations between MBG-which increases with salt consumption-and early cardiovascular risk markers support the global efforts to reduce population-wide salt intake in an effort to prevent and control the burden of non-communicable diseases.

Quantitative Measurements of Codeine and Fentanyl on a Surface-Enhanced Raman-Active Pad Test.

The USA is in the midst of an opioid crisis that included over 60,000 overdose fatalities in 2017, mostly unintentional. This is due to excessive use of prescription opioids and the use of very strong synthetic opioids, such as fentanyl, mixed with illicit street drugs. The ability to rapidly determine if people or packages entering the country have or contain drugs could reduce their availability, and thereby decrease the use of illicit drugs. In an effort to address this problem, we have been investigating the ability of surface-enhanced Raman spectroscopy to detect trace amounts of opioids on clothing and packages. Here, we report the measurement of codeine and fentanyl at 100 ng/mL for 5 min on a pad impregnated with gold colloids, as well as a preliminary measurement of 500 pg of fentanyl on a glass surface using one of these pads. The calculated limit of detection for this measurement was 40 pg. This data strongly suggests that these pads, used with portable Raman analyzers, would be invaluable to airport security, drug raids, crime scenes, and forensic analysis.

Leptin and its Relation to Autonomic Activity, Endothelial Cell Activation and Blood Pressure in a Young Black and White Population: The African-PREDICT study.

An increasing prevalence of obesity-related hypertension is observed in the youth and may have severe consequences for future cardiovascular disease development. Previous studies portrayed leptin as a potential factor involved in obesity-related hypertension development. In order to understand leptin's contributions to early cardiovascular deterioration, we investigated leptin and its associations with measures of autonomic activity, endothelial activation, and blood pressure in young healthy black and white men and women. We included 820 participants (aged 20-30 years) and determined serum leptin and endothelial cellular adhesion molecules. We measured 24-h blood pressure, heart rate, and heart rate variability components. In multivariate-adjusted regression analyses, we found consistent associations between markers of autonomic activity (such as 24-h heart rate, day and night-time heart rate as well as heart rate variability total power) and leptin in both white (all p≤0.001) and black men (all p≤0.040). These findings were absent or less prominent in women, despite their almost 10-fold higher leptin levels than men. Only in white men, 24-h diastolic blood pressure was associated with leptin (Std ß=0.37; p=0.006). This association was found to be partly mediated by autonomic activity (24-h heart rate variability total power). No independent associations were observed between leptin and markers of endothelial cell activation, irrespective of race or gender. Leptin's independent association with autonomic neural activity in a young apparently healthy population suggests an early influence of leptin on autonomic function and future blood pressure elevation especially in men.

Large artery stiffness is associated with salt intake in young healthy black but not white adults: the African-PREDICT study.

PURPOSE: There is global consensus on the benefits of reducing excessive salt intake. Indeed, lower salt intake associates with reduced arterial stiffness, a well-established predictor of cardiovascular risk, in older populations. Whether high habitual salt intake in healthy normotensive youth may already contribute to increased arterial stiffness is unknown. We, therefore, determined whether estimated salt intake is associated with large artery stiffness in young healthy black and white adults. METHODS: We included 693 black and white adults (51% black; 42% men), aged 20-30 years. Participants were normotensive based on clinic blood pressure, and no previous diagnosed chronic illnesses. We measured carotid femoral pulse wave velocity (cfPWV) and determined estimated salt intake based on 24 h urinary sodium excretion. RESULTS: We found estimated salt consumption of > 5 g/day in 47% of our population, whereas 21% consumed > 10 g/day. In multivariable-adjusted regression analyses a positive association existed between estimated salt intake and cfPWV in the total group (Adj. R2 = 0.32; std. ß = 0.10; p = 0.007), and black adults (Adj. R2 = 0.37; std. ß = 0.12; p = 0.029). This was independent of age, sex, mean arterial pressure, and other covariates. No association was evident in white individuals (p = 0.19). CONCLUSION: Excessive salt intake is positively associated with large artery stiffness-independent of blood pressure-in young adults, especially in black individuals. Our results suggest a potential contributory role of salt consumption towards early vascular aging.