Exploring soluble urokinase plasminogen activator receptor and its relationship with arterial stiffness in a bi-ethnic population: the SAfrEIC-study.

Introduction: Elevated soluble urokinase-type plasminogen activator receptor (suPAR) indicates an inflammatory state caused by conditions such as HIV and cancer. Recently suPAR was identified as an indicator of cardiovascular disease (CVD). CVD is highly prevalent in black South Africans, but the potential role of suPAR is unknown. We investigated suPAR as a possible marker of arterial stiffness in Africans and Caucasians.

Methods: This study involved 207 Africans and 314 Caucasians (aged 20-70 yrs). C-reactive protein (CRP) and suPAR were determined in fasting blood samples. We measured blood pressure, pulse wave velocity (PWV) and Windkessel arterial compliance (Cwk).

Results: Africans displayed higher suPAR, CRP, PWV and lower Cwk (p<0.001) compared to Caucasians. SuPAR was elevated in Africans irrespective of gender and smoking. We found strong relationships between PWV and suPAR (r=0.27; p<0.001) and Cwk and suPAR (r=-0.39; p<0.001) in the whole group, but found no independent relationship of any arterial stiffness measure and suPAR in Africans after adjustment for confounders. Caucasian men indicated a weak significant independent association between Cwk and suPAR (β=-0.09; p=0.028).

Conclusion: Africans had higher levels of suPAR and arterial stiffness than Caucasians (p<0.001), but there was no independent relationship between arterial stiffness and suPAR in the Africans. It is speculated that due to the inflammatory role of suPAR, it will have stronger relationships with atherosclerosis, which has not yet manifested in this relatively young population group. SuPAR may therefore not be an ideal early marker of cardiovascular dysfunction, but may rather indicate established CVD.