Adaptation of vasomotor function of human coronary arterioles to the simultaneous presence of obesity and hypertension.
OBJECTIVE
We hypothesized that simultaneous presence of obesity and hypertension activates adaptive vascular mechanisms affecting dilations of human coronary arterioles.


RESULTS
Agonist-induced dilations were assessed in isolated pressurized coronary arterioles from patients (n=38) who underwent cardiac surgery. Among normotensives we found that dilations to bradykinin (BK) and the NO-donor, sodium-nitroprusside (SNP) were reduced in obese subjects (BK, 10(-7) mol/L, lean: 90+/-4%, obese: 64+/-7%; SNP, 10(-6) mol/L, lean: 89+/-7%, obese: 76+/-5%). However, among hypertensives, both BK- and SNP-induced dilations were significantly enhanced in obese patients, when compared with lean individuals (BK, lean: 71+/-7%, obese: 85+/-3%; SNP, lean: 60+/-6%, obese: 83+/-2%). Correspondingly, in hypertensive patients, but not in those of normotensives, a positive correlation was found between body mass index (BMI) and BK-induced (P=0.036, r=0.46), and also SNP-evoked (P=0.031, r=0.44) coronary dilations. Moreover, in additional 55 hypertensive patients flow-mediated (FMD) and nitroglycerin (NTG)-induced dilations of the brachial artery were assessed. In obese hypertensive individuals, FMD- and NTG-induced dilations were greater (FMD: 6.2+/-0.7%, NTG: 17.2+/-0.9%), than in lean hypertensive patients (FMD: 3.7+/-0.6%, NTG: 13.6+/-1.1%). Correspondingly, FMD- and NTG-induced dilations were positively correlated with BMI (P=0.020, r=0.31 and P=0.033, r=0.29, respectively).


CONCLUSIONS
These findings are the first to suggest that obesity may lead to activation of adaptive vascular mechanisms to enhance the dilator function of coronary and peripheral arterial vessels in hypertensive patients.
Fulop
Tibor
T
Institute of Cardiology, University of Debrecen, Moricz Zs. Krt. 22, 4032-Debrecen, Hungary.
Jebelovszki
Eva
E
Erdei
Nora
N
Szerafin
Tamas
T
Forster
Tamas
T
Edes
Istvan
I
Koller
Akos
A
Bagi
Zsolt
Z
D000368:Aged; D001160:Arterioles / Q000503:physiopathology; D015992:Body Mass Index; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001920:Bradykinin / Q000494:pharmacology / Q000502:physiology; D003331:Coronary Vessels / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D014463:Ultrasonography; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology