OBJECTIVE: Established hypertension is characterized by increased peripheral vascular resistance and endothelial dysfunction, features that may underlie the reduced exercise-induced vasodilatation seen in hypertensive patients. Sildenafil citrate is a phosphodiesterase type 5 (PDE5) inhibitor used clinically for the treatment of male erectile dysfunction. Its vasodilating properties are due to the inhibition of cyclic guanosine monophosphate (cGMP) breakdown and prolongation of the signalling actions of the nitric oxide (NO)-cGMP pathway in vascular smooth muscle cells. Sildenafil has beneficial effects on endothelial function and exercise tolerance in congestive heart failure and pulmonary hypertension, and we hypothesized that it would improve exercise-induced vasodilatation in hypertensive patients. METHODS AND RESULTS: Ten hypertensive patients and ten matched normotensive subjects were studied in a three-way, randomized, single-blind and placebo-controlled study. On each study day, forearm blood flow (FBF) responses to handgrip exercise were assessed before and after intra-arterial (brachial) infusion of sildenafil, verapamil (a control, cGMP-independent vasodilator), and saline (placebo). Preinfusion exercise-induced vasodilatation was significantly reduced in hypertensive patients compared to normotensive controls. Sildenafil and verapamil infusions both caused a similar increase in baseline FBF. However, while verapamil did not affect the vasodilator response to handgrip exercise in either group, sildenafil substantially enhanced this response in hypertensive patients, but not in normotensive subjects. CONCLUSIONS: Our data suggest that sildenafil, through an increase in cGMP levels in the vasculature, substantially and selectively improves the vasodilator response to handgrip exercise in hypertensive patients. These findings represent an essential first step in support of further studies exploring the potentially beneficial effects of PDE5 inhibition on impaired exercise capacity in hypertension.
RCT Entities:
OBJECTIVE: Established hypertension is characterized by increased peripheral vascular resistance and endothelial dysfunction, features that may underlie the reduced exercise-induced vasodilatation seen in hypertensivepatients. Sildenafil citrate is a phosphodiesterase type 5 (PDE5) inhibitor used clinically for the treatment of male erectile dysfunction. Its vasodilating properties are due to the inhibition of cyclic guanosine monophosphate (cGMP) breakdown and prolongation of the signalling actions of the nitric oxide (NO)-cGMP pathway in vascular smooth muscle cells. Sildenafil has beneficial effects on endothelial function and exercise tolerance in congestive heart failure and pulmonary hypertension, and we hypothesized that it would improve exercise-induced vasodilatation in hypertensivepatients. METHODS AND RESULTS: Ten hypertensivepatients and ten matched normotensive subjects were studied in a three-way, randomized, single-blind and placebo-controlled study. On each study day, forearm blood flow (FBF) responses to handgrip exercise were assessed before and after intra-arterial (brachial) infusion of sildenafil, verapamil (a control, cGMP-independent vasodilator), and saline (placebo). Preinfusion exercise-induced vasodilatation was significantly reduced in hypertensivepatients compared to normotensive controls. Sildenafil and verapamil infusions both caused a similar increase in baseline FBF. However, while verapamil did not affect the vasodilator response to handgrip exercise in either group, sildenafil substantially enhanced this response in hypertensivepatients, but not in normotensive subjects. CONCLUSIONS: Our data suggest that sildenafil, through an increase in cGMP levels in the vasculature, substantially and selectively improves the vasodilator response to handgrip exercise in hypertensivepatients. These findings represent an essential first step in support of further studies exploring the potentially beneficial effects of PDE5 inhibition on impaired exercise capacity in hypertension.
Authors: Jacqueline K Limberg; Katherine R Malterer; J Mikhail Kellawan; William G Schrage; Brad W Wilkins; Wayne T Nicholson; John H Eisenach; Michael J Joyner; Timothy B Curry Journal: Eur J Appl Physiol Date: 2016-12-24 Impact factor: 3.078
Authors: Peter Steele; Geoff Strange; John Wlodarczyk; Brad Dalton; Simon Stewart; Eli Gabbay; Anne Keogh Journal: BMC Cardiovasc Disord Date: 2010-02-22 Impact factor: 2.298
Authors: J Mikhail Kellawan; Jacqueline K Limberg; Zachariah M Scruggs; Wayne T Nicholson; William G Schrage; Michael J Joyner; Timothy B Curry Journal: J Appl Physiol (1985) Date: 2017-10-05