ORCID Profile
0000-0001-5099-3408
Current Organisation
North-West University
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Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 12-2020
Publisher: Hindawi Limited
Date: 10-2016
Abstract: The objective of this study was to make use of a quantitative and qualitative approach comparing the systemic renin-angiotensin system (RAS) of hypertensive black and white African men by using RAS equilibrium analysis. This sub-study involved 23 black ( n = 15) and white ( n = 8) hypertensive men aged 39.5–41 years, living in the North West Province of South Africa. The RAS-Fingerprinting was determined with LC-MS/MS quantification of angiotensin peptides. Blood pressure and other variables were determined with known methods. The main finding of this study was the significant lower Ang I ( .0 and 45.1 pg/ml p = 0.005) and Ang II (15.6 and 123.9 pg/ml p ⩽ 0.001) encountered in the hypertensive black African men compared to their white counterparts. Levels of Ang 1-5 (downstream metabolite of Ang 1-7) (1.8 and 3.0 pg/ml), were detected in black and white hypertensive men, respectively. The observed differences between circulating RAS components, which are reflected via equilibrium angiotensin levels, point to a distinctive molecular regulation of the RAAS in the two study cohorts. The increased peripheral resistance observed in hypertensive black in iduals might take over a dominant role in control of blood pressure in this study population. A novel highly sensitive LC-MS/MS method resolved the issue of peptide recovery variations during s le preparation by using internal standards for each in idual angiotensin metabolite.
Publisher: Wiley
Date: 22-05-2014
DOI: 10.1111/ECI.12278
Abstract: Soluble urokinase plasminogen activator receptor (suPAR), a novel indicator of low-grade inflammation, is associated with cardiovascular disease and mortality in the general population, while an unhealthy lifestyle influences inflammatory status. We aimed to explore the relationship of suPAR with lifestyle and cardiometabolic risk factors in a black South African population. This cross-sectional study includes 1068 men and women (56·4 ± 10·1 years) from the North West province who took part in the South African leg of the Prospective Urban and Rural Epidemiology (PURE) study in 2010. Captured data included a detailed lifestyle profile (tobacco use, alcohol consumption, physical activity, psychological and dietary intake status), biochemical analyses (suPAR, C-reactive protein (CRP), glucose and lipids), as well as cardiovascular and anthropometric measurements. In exploratory analyses, we observed positive relationships between suPAR and lifestyle factors, such as tobacco use (P-trend < 0·001), both alcohol consumption (P-trend = 0·001) and γ-glutamyl transferase (GGT) (P-trend < 0·001) and unemployment (P-trend = 0·002). suPAR and CRP correlated significantly (r = 0·23 P < 0·001). These relationships were confirmed in multiple regression analyses as suPAR independently associated with tobacco use (β = 0·13 P < 0·001), GGT (β = 0·24 P < 0·001) and unemployment (β = 0·07 P = 0·039). suPAR did not associate with the cardiometabolic factors glucose, lipids, blood pressure or measures of adiposity. suPAR was independently associated with unhealthy lifestyle behaviours, but not with cardiometabolic risk factors suggesting that suPAR, as known predictor of cardiovascular disease and mortality, is augmented by modifiable cardiovascular risk factors. These findings emphasise the need for a healthy lifestyle to decrease the burden of cardiovascular disease in Africans.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.CYTO.2019.154894
Abstract: Inflammatory mediators have been implicated in the early stages of cardiovascular disease development, including hypertension. Since global reports reflect a higher hypertension prevalence in black than white populations, we hypothesise the involvement of specific inflammatory mediators. We therefore compared a detailed range of 22 inflammatory mediators between young black and white adults, and determined the relationship with blood pressure. We included 1197 adults (20-30 years 50% black 52% female) with detailed ambulatory blood pressures. Blood s les were analysed for 22 inflammatory mediators. For pro-inflammatory mediators, the black adults had higher C-reactive protein, interferon-inducible T-cell alpha chemoattractant, macrophage inflammatory protein 3 alpha (all p ≤ 0.008), but lower interferon-gamma, interleukin (IL)-1β, IL-8, IL-12, IL-17A, and tumour necrosis factor alpha (all p ≤ 0.048). For anti-inflammatory mediators the black group consistently had lower levels (IL-5, IL-10 and IL-13 (all p ≤ 0.012)), resulting in generally higher pro-to-anti-inflammatory ratios in black than white adults (p ≤ 0.001). In mediators with pro- and anti-inflammatory functions, the black group had lower granulocyte-macrophage colony-stimulating factor and IL-6 (both p ≤ 0.010). These patterns were confirmed after adjustment for age, sex and waist circumference, or when stratifying by hypertensive status, sex and socio-economic status. Multi-variable adjusted regression analyses and factor analysis yielded no relationship between inflammatory mediators and blood pressure in this young healthy population. Black and white ethnic groups each consistently presented with unique inflammatory mediator patterns regardless of blood pressure, sex or social class. No association with blood pressure was seen in either of the groups.
Publisher: Oxford University Press (OUP)
Date: 28-07-2016
Abstract: Inconsistent findings are reported on whether insulin-like growth factor-1 (IGF-1) is protective or harmful in predicting hypertension, carotid wall thickness and mortality. We determined the five-year prognostic value of IGF-1 for these outcomes in a large Black population prone to hypertension and cardiovascular disease. A longitudinal study as part of the PURE (Prospective Urban and Rural Epidemiology) study, North West Province, South Africa. We measured IGF-1 and IGF binding protein-3 (IGFBP-3) in 1038 HIV-uninfected participants (age range 32-94 years) and assessed blood pressure, carotid intima-media thickness and mortality. Over five years 116 deaths occurred. Baseline IGF-1 was similar in survivors and non-survivors (p = 0.50), but tended to be higher in survivors upon adjustment for IGFBP-3 and covariates (p = 0.061). Normotensives and hypertensives (p = 0.072), and those with carotid intima-media thickness < 0.9 mm and ≥ 0.9 mm also displayed similar baseline IGF-1 (p = 0.55). Multivariable-adjusted Cox-regression indicated high IGF-1 predicting lower risk for all-cause mortality (hazard ratio 0.45 0.23-0.88) and cardiovascular mortality (hazard ratio 0.26 0.08-0.83) when also adjusting for IGFBP-3. When including normo- and hypertensives at baseline, high IGF-1 was related to normotension at follow-up (hazard ratio 0.68 0.49-0.95). We found no association with carotid intima-media thickness (hazard ratio 0.59 0.31-1.14). In a Black South African population with low socio-economic status and harmful health behaviours, we found a protective independent association between IGF-1 and hypertension, cardiovascular and all-cause mortality, with no association with carotid wall thickness.
Publisher: Elsevier BV
Date: 04-2021
DOI: 10.1016/J.NUMECD.2020.12.021
Abstract: 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 otassium 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. 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 in iduals, urinary potassium excretion was independently and negatively associated with SDNN (β[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 otassium (Na/K) ratio was associated with higher SDNN (β[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). 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 in iduals. ClinicalTrials.gov Identifier: NCT03292094 URL: t2/show/NCT03292094.
Publisher: Springer Science and Business Media LLC
Date: 23-03-2017
DOI: 10.1038/JHH.2017.18
Abstract: Consistent reports indicate that hypertension is a particularly common finding in black populations. Hypertension occurs at younger ages and is often more severe in terms of blood pressure levels and organ damage than in whites, resulting in a higher incidence of cardiovascular disease and mortality. This review provides an outline of recent advances in the pathophysiological understanding of blood pressure elevation and the consequences thereof in black populations in Africa. This is set against the backdrop of populations undergoing demanding and rapid demographic transition, where infection with the human immunodeficiency virus predominates, and where under and over-nutrition coexist. Collectively, recent findings from Africa illustrate an increased lifetime risk to hypertension from foetal life onwards. From young ages black populations display early endothelial dysfunction, increased vascular tone and reactivity, microvascular structural adaptions as well as increased aortic stiffness resulting in elevated central and brachial blood pressures during the day and night, when compared to whites. Together with knowledge on the contributions of sympathetic activation and abnormal renal sodium handling, these pathophysiological adaptations result in subclinical and clinical organ damage at younger ages. This overall enhanced understanding on the determinants of blood pressure elevation in blacks encourages (a) novel approaches to assess and manage hypertension in Africa better, (b) further scientific discovery to develop more effective prevention and treatment strategies and
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.IJCARD.2015.03.041
Abstract: Elevated inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) are well-known risk factors for cardiovascular mortality. The less familiar marker, soluble urokinase plasminogen activator receptor (suPAR), is known to predict cancer, infections and all-cause mortality. We determined whether suPAR, CRP and IL-6 are predictive of both all-cause and cardiovascular mortality in a black population, highly burdened by cardiovascular disease and HIV infection. We included 1425 black South Africans, of which 208 died within five years after baseline data collection. EDTA plasma biomarker levels were determined, while all-cause and cardiovascular mortality were used as endpoints. At baseline suPAR, CRP and IL-6 were higher in non-survivors than in survivors (P<0.001). SuPAR (HR 1.27, 95% CI 1.09-1.48), IL-6 (HR 1.49, 95% CI 1.24-1.78) and CRP (HR 1.39, 95% CI 1.17-1.65) predicted all-cause mortality, while only suPAR (HR 1.40, 95% CI 1.04-1.87) and IL-6 (HR 1.61, 95% CI 1.10-2.35) predicted cardiovascular mortality. The prognostic value of suPAR was independent of IL-6 and CRP (P≤0.015). SuPAR predicted both all-cause and cardiovascular mortality, independent of traditional risk factors, HIV and other inflammatory markers, underlining the prognostic value of suPAR in a black population.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.HLC.2013.07.019
Abstract: The use of antiretroviral treatment is known to be accompanied by several negative health outcomes and may negatively affect a country such as South Africa, which is the most burdened by the human immunodeficiency virus (HIV) in the world. We aimed to determine whether receiving antiretroviral treatment changes the cardiometabolic profile of HIV-infected South Africans. In this sub-study, embedded in the Prospective Urban and Rural Epidemiology (PURE) study, we compared the cardiometabolic profile in a cohort of 66 treated and 71 never treated HIV-infected participants from the North-West province, South Africa. By using standard techniques, these participants' cardiometabolic, biochemical and lifestyle variables were assessed in 2005 and 2010, respectively. The treated group showed a higher percentage change in pulse pressure (13.3% p = 0.004), systolic blood pressure (4.5% p = 0.029) and CD4 cell count (9.2% p = 0.009) levels over five years. During follow-up (2010), lipid variables were worse in the treated group. Further, antiretroviral treatment was associated with the percentage change in pulse pressure (R(2) = 0.24 β = 0.19 p = 0.020). We concluded that Africans receiving antiretroviral treatment had a greater increase in pulse pressure and systolic blood pressure, as well as an unfavourable lipid profile when compared to never treated participants. Whether, in the long term, antiretroviral treatment will lead to increased arterial stiffness and/or accelerated atherosclerosis among this HIV-infected African population remains to be seen.
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.JASH.2014.12.003
Abstract: Evidence of the relationship between left ventricular hypertrophy and urinary albumin excretion is contradictory and limited in black adults in whom hypertensive heart disease is common. We aimed to investigate the relationship between subclinical left ventricular hypertrophy and albuminuria in non-diabetic hypertensive blacks. Urinary albumin-to-creatinine ratio (UACR) was determined from 8-hour overnight urine collection. We recorded ambulatory blood pressure and 12-lead electrocardiogram during a typical working day. Cornell product (P = .002), UACR (P = .042), 24-hour systolic pressure (P < .0001), and 24-hour pulse pressure (P < .0001) were higher in the hypertensive group. Cornell product was associated with UACR in single (r = 0.25 P = .012), partial (P trend = .002), and multiple regression (β = 0.326 P = .0005) analyses in the hypertensive group only, even below the threshold for microalbuminuria and independent of 24-hour systolic pressure. Urinary albumin excretion is associated with subclinical left ventricular hypertrophy in non-diabetic hypertensive blacks and may be a useful marker of early cardiovascular disease in blacks.
Publisher: Springer Science and Business Media LLC
Date: 05-03-2015
DOI: 10.1038/HR.2015.22
Abstract: Soluble urokinase plasminogen activator receptor (suPAR) is a biomarker that links inflammation with cardiovascular risk. However, studies linking suPAR and hypertension are scant. First, we determined whether baseline suPAR is elevated in normotensive black South Africans who developed hypertension over 5 years, compared with those who remained normotensive and second, whether hypertension is associated with suPAR. This substudy is embedded in the South African leg of the Prospective Urban and Rural Epidemiology study, performed in the North West Province. We investigated 429 normotensive in iduals, of which 191 developed hypertension and 238 remained normotensive over 5 years. We determined suPAR from plasma (ethylenediaminetetraacetic acid) s les with the suPARnostic ELISA Kit and blood pressure with an OMRON HEM-757 device. Despite similar mean baseline suPAR levels (P=0.43), suPAR increased more in the group that developed hypertension compared with those who remained normotensive (14.2% vs. 6.94% P=0.007). Five-year percentage change in systolic blood pressure correlated positively (r=0.23 P=0.002) and associated independently with baseline suPAR (β=0.14 P=0.043), only in participants who developed hypertension. Participants were 1.41 times more likely (P=0.015) to develop hypertension with 1 s.d. increase in percentage change in suPAR levels over 5 years. Change in systolic blood pressure was associated with baseline suPAR in hypertensive participants and change in suPAR with hypertensive status. This study highlights the need for more research on the role of suPAR in hypertension and cardiovascular disease development in black South Africans.
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.CLNU.2018.05.008
Abstract: The relationship between total body iron and cardiovascular disease remains controversial and information absent in black sub-Saharan Africans in whom alcohol consumption tends to be high. The level of total body iron is tightly regulated, however this regulation is compromised by high alcohol intake causing iron loading. The aim of this study is to investigate total body iron, as represented by serum ferritin, and its interaction with measures of alcohol intake in predicting all-cause and cardiovascular mortality. We followed health outcomes for a median of 9.22 years in 877 randomly selected HIV negative African women (mean age: 50.4 years). One hundred and five deaths occurred of which 40 were cardiovascular related. Ferritin averaged 84.0 (5th to 95th percentile interval, 7.5-533.3) ng/ml and due to the augmenting effect of inflammation, lowered to 75.3 (6.9-523.2) ng/ml after excluding 271 participants with high-sensitivity C-reactive protein (CRP) levels (above 8 mg/l). CRP increased by quartiles of ferritin in the total group (P trend = 0.002), but this relationship was absent after excluding the 271 participants with high CRP values (P trend = 0.10). Ferritin, gamma-glutamyl transferase and carbohydrate deficient transferrin (all P < 0.0001) were higher in drinkers compared to non-drinkers, but CRP was similar (P = 0.77). In multivariable-adjusted analyses, ferritin predicted both all-cause (hazard ratio, 2.08 95% confidence interval, 1.62-2.68 P < 0.0001) and cardiovascular (1.94 1.29-2.92 P = 0.002) mortality. In participants with CRP levels below or equal to 8 mg/l, the significant relationship remained between ferritin and all-cause (2.51 1.81-3.49 P < 0.0001) and cardiovascular mortality (2.34 1.45-3.76 P = 0.0005). In fully adjusted models, interactions existed between ferritin and gamma-glutamyl transferase, self-reported alcohol use and carbohydrate deficient transferrin in predicting all-cause (P ≤ 0.012) and cardiovascular mortality (P ≤ 0.003). Iron loading in African women predicted all-cause and cardiovascular mortality and the intake of alcohol seems mechanistically implicated.
Publisher: Oxford University Press (OUP)
Date: 06-01-2019
Abstract: Globally hypertension is stabilising, but in sub-Saharan Africa the incidence of hypertension remains on an increase. Although this might be attributed to poor healthcare and ineffective antihypertensive treatment, there is a limited understanding of population and in idual-specific cardiovascular pathophysiology – necessary for effective prevention and treatment strategies in Africa. As there is a lack of longitudinal studies tracking the early pathophysiological development of hypertension in black populations, the African-PREDICT study was initiated. The purpose of this paper is to describe the detailed methodology and baseline cohort profile of the study. From 2013 to 2017, the study included 1202 black ( N = 606) and white ( N = 596) men and women (aged 20–30 years) from South Africa – screened to be healthy and clinic normotensive. At baseline, and each 5-year follow-up examination, detailed measures of health behaviours, cardiovascular profile and organ damage are taken. Also, comprehensive biological s ling for the ‘omics’ and biomarkers is performed. Overall, the baseline black and white cohort presented with similar ages, clinic and 24-hour blood pressures, but black adults had lower socioeconomic status and higher central systolic blood pressure than white in iduals. The prospective African-PREDICT study in young black and white adults will contribute to a clear understanding of early cardiovascular disease development.
Publisher: Springer Science and Business Media LLC
Date: 03-06-2020
DOI: 10.1007/S00394-020-02292-3
Abstract: Low-grade inflammation and a diet high in salt are both established risk factors for cardiovascular disease. High potassium (K + ) intake was found to counter increase in blood pressure due to high salt intake and may potentially also have protective anti-inflammatory effects. To better understand these interactions under normal physiological conditions, we investigated the relationships between 22 inflammatory mediators with 24-h urinary K + in young healthy adults stratified by low, medium and high salt intake (salt tertiles). We stratified by ethnicity due to potential salt sensitivity in black populations. In 991 healthy black ( N = 457) and white ( N = 534) adults, aged 20–30 years, with complete data for 24-h urinary sodium and K + , we analysed blood s les for 22 inflammatory mediators. We found no differences in inflammatory mediators between low-, mid- and high-sodium tertiles in either the black or white groups. In multivariable-adjusted regression analyses in white adults, we found only in the lowest salt tertile that K + associated negatively with pro-inflammatory mediators, namely interferon gamma, interleukin (IL) -7, IL-12, IL-17A, IL-23 and tumour necrosis factor alpha (all p ≤ 0.046). In the black population, we found no independent associations between K + and any inflammatory mediator. In healthy white adults, 24-h urinary K + associated independently and negatively with specific pro-inflammatory mediators, but only in those with a daily salt intake less than 6.31 g, suggesting K + to play a protective, anti-inflammatory role in a low-sodium environment. No similar associations were found in young healthy black adults.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Shani Le Roux.