TY - JOUR
T1 - Effects of angiotensin II type 1-receptor blockade on retinal endothelial function
AU - Ott, Christian
AU - Schlaich, Markus P.
AU - Harazny, Joanna
AU - Schmidt, Bernhard M.W.
AU - Michelson, Georg
AU - Schmieder, Roland E.
PY - 2008/3
Y1 - 2008/3
N2 - OBJECTIVE: Hypercholesterolemia is an important risk factor for atherosclerotic vascular disease including stroke. Low-density lipoprotein-cholesterol may induce upregulation of angiotensin II type 1 (AT1)-receptors and their activation plays a pathogenetic role in atherosclerosis, possibly via enhanced breakdown of nitric oxide. We tested whether AT1-receptor blockade improved endothelial function of the retinal vasculature in normocholesterolemic and hypercholesterolemic subjects. METHODS: Thirty-one hypercholesterolemic and 17 normocholesterolemic subjects were randomly assigned to treatment with irbesartan and placebo in a double-blind crossover study. Retinal capillary flow was measured using scanning laser Doppler flowmetry. Diffuse luminance flicker was applied to provoke vasodilation that is in part nitric oxide dependent. RESULTS: Flicker-induced increases in retinal capillary flow were similar between hypercholesterolemic and normocholesterolemic subjects. In contrast to placebo, treatment with irbesartan led to a significant reduction of blood pressure, in our patients with normal blood pressure values. Therefore we divided our study cohort according to the median blood pressure reduction in response to irbesartan. Flicker-induced increases in retinal capillary flow were substantially higher in subjects with a systolic blood pressure reduction above median (> 6 mmHg) than in those with a reduction below median (≤6 mmHg) (16.2 ± 16% versus 6.88 ± 11%; P = 0.042). CONCLUSION: AT1-receptor blockade with irbesartan improves endothelial function of the retinal vasculature, taken as a model of cerebral circulation.
AB - OBJECTIVE: Hypercholesterolemia is an important risk factor for atherosclerotic vascular disease including stroke. Low-density lipoprotein-cholesterol may induce upregulation of angiotensin II type 1 (AT1)-receptors and their activation plays a pathogenetic role in atherosclerosis, possibly via enhanced breakdown of nitric oxide. We tested whether AT1-receptor blockade improved endothelial function of the retinal vasculature in normocholesterolemic and hypercholesterolemic subjects. METHODS: Thirty-one hypercholesterolemic and 17 normocholesterolemic subjects were randomly assigned to treatment with irbesartan and placebo in a double-blind crossover study. Retinal capillary flow was measured using scanning laser Doppler flowmetry. Diffuse luminance flicker was applied to provoke vasodilation that is in part nitric oxide dependent. RESULTS: Flicker-induced increases in retinal capillary flow were similar between hypercholesterolemic and normocholesterolemic subjects. In contrast to placebo, treatment with irbesartan led to a significant reduction of blood pressure, in our patients with normal blood pressure values. Therefore we divided our study cohort according to the median blood pressure reduction in response to irbesartan. Flicker-induced increases in retinal capillary flow were substantially higher in subjects with a systolic blood pressure reduction above median (> 6 mmHg) than in those with a reduction below median (≤6 mmHg) (16.2 ± 16% versus 6.88 ± 11%; P = 0.042). CONCLUSION: AT1-receptor blockade with irbesartan improves endothelial function of the retinal vasculature, taken as a model of cerebral circulation.
KW - Angiotensin II type 1-receptor blockers
KW - Cerebrovascular circulation
KW - Endothelium
KW - Hypercholesterolemia
KW - Nitric oxide
UR - http://www.scopus.com/inward/record.url?scp=39849089027&partnerID=8YFLogxK
U2 - 10.1097/HJH.0b013e3282f3adb0
DO - 10.1097/HJH.0b013e3282f3adb0
M3 - Article
C2 - 18300863
AN - SCOPUS:39849089027
SN - 0263-6352
VL - 26
SP - 516
EP - 522
JO - Journal of Hypertension
JF - Journal of Hypertension
IS - 3
ER -