CENTRAL OBESITY AND HYPERTENSION - THE ROLE OF PLASMA ENDOTHELIN

Hypertension and central obesity are two conditions closely linked, bu t the mechanisms responsible for obesity-associated hypertension are s till unclear. In the last few years, several studies addressed the rol e of endothelin-1 (ET-1) in the development and maintenance of hyperte nsion. This study was designed to evaluate plasma ET-1 in normotensive and hypertensive central obese subjects compared with a lean healthy group. Our final goal was to analyze the relationship between plasma E T-1, blood pressure, and left ventricular structure and function in ce ntral obese subjects (both normotensives and hypertensives). ET-levels have been assessed by the radioimmunoassay method in 20 lean normoten sives and in 57 central obese subjects; 30 of them were hypertensives and 27 of them were normotensives. Twenty-four-hour mean blood pressur e (MBP/24 h) by noninvasive ambulatory blood pressure monitoring, left ventricular mass/ height (LVM/H), and left ventricular ejection fract ion (LVEF) by echocardiography and peak filling rate (PFR) by radionuc lide study were also measured. ET levels were significantly (P <.05) h igher in obese hypertensives and obese normotensives than in lean norm otensives. In addition, ET levels were significantly (P <.05) higher i n obese hypertensives than in obese normotensives. ET were directly re lated to LVM/H (r = 0.86; P <.001) and MBP/24 h (r = 0.48; P <.009) bu t only in obese hypertensives. Multiple regression analysis indicated that ET-1 plasma levels remain an independent predictor of MBP/24 h an d LVM/H also when age was included in the analysis. These data suggest that obesity-associated hypertension is characterized by an endotheli al dysfunction that may contribute to the higher cardiovascular risk d etectable in these patients. (C) 1996 American Journal of Hypertension , Ltd.