ENDOGENOUS ERYTHROPOIETIN CORRELATES WITH BLOOD-PRESSURE IN ESSENTIAL-HYPERTENSION

Patients on maintenance hemodialysis with a family history of essentia l hypertension are at higher risk for increased arterial blood pressur e when treated with erythropoietin than patients without family histor y. This study was performed to elucidate the role of endogenous erythr opoietin in essential hypertension. We conducted a study in 42 untreat ed patients (mean age, 51 +/- 9 years) with essential hypertension Wor ld Health Organization stages I or II. Ambulatory 24-hour blood pressu re (Spacelab 90207), cardiac output (2D guided M-mode echocardiography and CW Doppler sonography), renal hemodynamics (paraaminohippurate an d inulin clearance), and endogenous erythropoietin (radioimmunoassay) together with erythrocyte count, hemoglobin, and hematocrit were measu red in parallel. Mean 24-hour systolic blood pressure was 145 +/- 13 m m Hg, and mean diastolic blood pressure was 93 +/- 8 mm Hg, The averag e erythropoietin concentration was 15.3 +/- 3.7 mU/mL and within the n ormal range. We found that the higher erythropoietin concentrations, t he more elevated was both 24-hour ambulatory systolic (r = 0.51, P < 0 .005) and diastolic blood pressure (r = 0.49, P < 0.005). Also, the co ncentration of endogeneous erythropoietin was correlated with total pe ripheral resistance as noninvasively determined by echocardiographic a nd Doppler sonographic measurements (r = 0.40, P < 0.02 and r = 0.49, P < 0.02, respectively), With increasing erythropoietin concentrations , renal plasma flow and renal blood flow were found to be progressivel y reduced (r = -0.32, P < 0.05 and r = -0.35, P < 0.05, respectively) and renal vascular resistance increased (r = 0.41, P < 0.01). Neither hematocrit nor hemoglobin nor erythrocyte count were related to endoge nous erythropoietin concentrations, In human essential hypertension, t he level of arterial blood pressure is related to endogenous erythropo ietin, which is hemodynamically mediated by an increase of total perip heral resistance. Because erythropoietin has shown proliferative and v asoconstricting effects on the endothelium in experimental studies, we suggest that endogenous erythropoietin might be an aggravating or eve n a promoting factor in the pathogenesis of essential hypertension. (C ) 1997 by the National Kidney Foundation, Inc.