Relationship between Arterial Blood Pressure, Angiotensin Ii and Leptin

Obesity and hypertension are two closely associated conditions and obesity probably predisposed to hypertension. The mechanism of the association between obesity and hypertension is not clear. The aim of the present study was to clarify the relationship between blood pressure (BP), body mass index (BMI), serum angiotensinII (AGII) & serum leptin levels and to investigate the relation between serum AGII & Leptin. This study also aimed to role out if there is a difference in serum AGII & leptin levels between lean and obese hypertensive females. We measured fasting serum AGII and leptin levels in 16 normotensive lean (LN) females, 25 obese normotensive (ON) females, 12 lean hypertensive (LH) females and 25 obese hypertensive (OH) females. All subjects had no evidence of pre-existing cardiovascular disease, were non pregnant, had no previous history of ill health or smoking and were not on antihypertensive therapy. In lean groups there were a significant increase in BMI & Serum AGII in hypertensive group compared to normotensive group while the serum leptin level was insignificantly higher in hypertensive group than in normotensive group. On the other hand there was a significant increase in serum AGII, BMI and serum leptin for obese hypertensive compared to obese normotensive group. The mean ABP was significantly correlated to serum AGII, serum leptin and BMI in all groups. A significant correlation was found between serum AGII and serum leptin if all studied females (LN, LH, ON & OH) or obese females (ON& OH) were analyzed (P = 0.000 &0.04). But in lean females (LN& LH) there was no relation between serum AGII & serum leptin. In CONCLUSION When obesity is present, both serum AGII & serum leptin were strong predictor of BP, which is not the case in lean females in whom only serum AGII is a predictor of BP. Elevation of serum AGII & serum leptin levels when associated with increased BMI may contribute to the pathophysiology of obesity-induced hypertension. Further study on leptin resistance in obese persons and its relation to incresded arterial blood pressure has to be done.