Introduction:
Morbidity and mortality attributable to hypertension are higher in African American (AAEH) compared to Caucasian essential hypertensive (EH) patients, possibly related to a differential effect on vascular injury and repair. While circulating endothelial progenitor cells (EPC) preserve endothelial integrity IEC detach from sites of injury and represent markers of vascular damage. We hypothesized that plasma levels of IEC and inflammatory markers would be higher in AAEH compared to EH patients.
METHODS:
Inferior vena cava levels of CD34+/KDR+ (EPC) and VAP-1+ (IEC) cells were measured by FACS in EH and AAEH under fixed sodium intake (150 mEq/d) and blockade of the renin-angiotensin-system, and compared to systemic levels in normotensive control subjects (n=19 each). Systemic levels of inflammatory cytokines and EPC homing factors were measured by Luminex.
Results:
Blood pressure, serum creatinine, lipids, antihypertensive medications, and EPC levels did not differ between EH and AAEH patients. Circulating IEC were higher in AAEH, and inversely correlated with EPC levels (Figure). Systemic levels of inflammatory cytokines and EPC homing factors were higher in AAEH compared to EH patients (Table), and correlated directly with IEC.
Conclusion:
Despite preserved kidney function and controlled BP, circulating inflammatory markers were elevated in AAEH and correlated with increased IEC and decreased EPC levels. Increased release of cytokines and IEC in AAEH may impair EPC reparative capacity and predispose to hypertensive vascular injury. This process may aggravate vascular damage and accelerate hypertension-related morbidity/mortality rates in AAEH.
The role of inflammation in vascular injury and repair
