Soluble urokinase plasminogen activator receptor and cardiovascular function in African and Caucasian populations : the SAfrEIC study
Motivation - Soluble urokinase plasminogen activator receptor (suPAR) is a known inflammatory marker, which is found in various body fluids. SuPAR reflects the immune and pro–inflammatory status of patients caused by HIV and tuberculosis, amongst others. However, recent studies have shown that suPAR is related to cardiovascular function. The cardiovascular health of the black South African population is a major health concern as this group suffers mostly from hypertension and stroke, leading to an alarming increase in cardiovascular morbidity and mortality. SuPAR may be able to contribute to early detection and prevention of cardiovascular diseases. No studies regarding the associations of suPAR with cardiovascular function have been investigated on black South Africans. Objectives - To investigate suPAR as a possible marker of cardiovascular function in African and Caucasian men and women, by determining possible gender and ethnic–specific associations of suPAR with cardiovascular function. Methodology - There were 207 African and 314 Caucasian men and women (aged 20–79 yrs.) included in this study. High–sensitivity C–reactive protein, glucose, lipids and creatinine were determined in fasting serum and suPAR was analyzed in plasma samples. Blood pressure was measured using the OMRON apparatus (HEM–747), with a 5–min rest interval between measurements. The Finometer device was used to determine the Windkessel compliance and the carotid dorsalis–pedis pulse wave velocity (PWV) was measured with the Complior (SP acquisition system) on the left side of each subject in the supine position. The means, adjusted means and proportions were compared between the groups by using independent t–tests, analysis of co–variance and the chi–square test, respectively. Associations were investigated between cardiovascular variables and suPAR using single and multiple regression analyses with either pulse wave velocity, systolic blood pressure, diastolic blood pressure or Windkessel compliance as dependent variable. Covariates included were age, body mass index, smoking, alcohol use, physical activity, glucose and high–density lipoprotein cholesterol. Results and conclusion - SuPAR levels were significantly higher in Africans (P<0.001) compared to Caucasians. After adjusting for body mass index, suPAR increased significantly with age in all groups, except for African women. Moreover, the suPAR levels of African men and women were significantly higher than the Caucasians within each age quartile. While adjusting for age and body mass index, the cardiovascular profiles of the African and Caucasian men were less favourable compared to women, but suPAR levels were significantly higher in Caucasian women compared to men. In single regression, various measures of cardiovascular function correlated with suPAR in African men and Caucasian men and women. After adjusting for confounders the associations disappeared in Caucasian women, and remained non-significant in the African women. However, the association between PWV and suPAR remained significant in African men (B=0.19; P=0.030), while the association of systolic blood pressure (B=0.20; P=0.017), diastolic blood pressure (B=0.17; P=0.020) and Windkessel compliance (B=–0.14; P=0.004) with suPAR remained significant in Caucasian men. In conclusion, Africans presented higher suPAR levels compared to Caucasians, even when stratified by age. Gender specific associations indicated that suPAR was associated with arterial stiffness in African and Caucasian men only, therefore, indicating that suPAR could be a possible biomarker for predicting cardiovascular dysfunction.
- Health Sciences