| Autor: |
Browne, D. L., Meeking, D. R., Allard, S. E., Munday, J. L., Shaw, K. M., Cummings, M. H. |
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| Zdroj: |
Diabetic Medicine; Jan2006, Vol. 23 Issue 1, p53-59, 7p |
| Abstrakt: |
Aims Previously, we have demonstrated that patients with normoalbuminuric Type 1 diabetes are characterized by impaired nitric oxide bioavailability compensated for by increased vasodilatory prostanoid-mediated vasodilation. Experimental evidence suggests vascular responses to endogenous angiotensin II involve the nitric oxide and prostaglandin pathways. We examined whether selective blockade of angiotensin II influences endothelial tone with particular reference to the nitric oxide/prostaglandin pathways in patients with Type 1 diabetes free from vascular complications. Methods At baseline, we studied changes in forearm blood flow in response to brachial arterial infusions of acetylcholine,l-NMMA, a combination ofl-NMMA and the cyclo-oxygenase inhibitor indomethacin and nitroprusside in 30 patients with normoalbuminuric Type 1 diabetes [21 male, 9 female; age 38.5 ± 1.9 years (mean ± sem)]. Patients were randomized to 2 weeks’ treatment with placebo or the selective angiotensin II receptor blocking agent irbesartan, 300 mg, prior to forearm vasoactive responses being re-examined. Results The forearm responses to nitroprusside and acetylcholine were unchanged by both placebo ( P = 0.23 and P = 0.36, respectively) and irbesartan ( P = 0.41 and P = 0.36). Similarily, dose–response curves to acetylcholine in the presense ofl-NMMA alone ( P = 0.42) and a combination ofl-NMMA and indomethacin ( P = 0.44) were not altered by angiotensin II blockade. Conclusion This study demonstrated that physiological blockade of endogenous angiotensin II in Type 1 diabetes does not augment agonist-evoked vasodilation or the contribution of nitric oxides and prostanoids to endothelial tone. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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