TY - JOUR
T1 - The ocular hemodynamic response to nitric oxide synthase inhibition is unaltered in patients with early type I diabetes
AU - Dorner, Guido T.
AU - Garhöfer, Gerhard
AU - Selenko, Nicole
AU - Fasching, Peter
AU - Bayerle-Eder, Michaela
AU - Schmetterer, Leopold
AU - Wolzt, Michael
PY - 2003/8/1
Y1 - 2003/8/1
N2 - Background: An impaired ocular hemodynamic response to systemic nitric oxide synthesis inhibition has been demonstrated in patients with long-standing insulin-dependent diabetes mellitus. It is unclear whether this altered responsiveness is already detectable in early uncomplicated type I diabetes. Methods: The effect of the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) was studied in 10 male patients with early type I diabetes under euglycemic conditions and 10 healthy matched control subjects in a single (analyst) blinded cohort study design. Changes in ocular hemodynamics (fundus pulsation amplitude, mean flow velocity in the ophthalmic artery) and in pulse rate and mean blood pressure were measured in response to systemic intravenous doses of 1.5, 3, and 6 mg/kg L-NMMA. Results: L-NMMA dose-dependently and significantly decreased fundus pulsation amplitude (-21.0% vs -23.3% in diabetics and controls, respectively), mean flow velocity in the ophthalmic artery (-12.3% vs -10.8%) and pulse rate (-15.4% vs -16.6%) and increased mean arterial pressure (+19.5% vs +14.7%). The ocular and systemic hemodynamic effects of L-NMMA were not different between patients with diabetes and controls. Conclusion: The responsiveness of the choroidal vasculature and the ophthalmic artery to L-NMMA is not altered in early type 1 diabetes. An impaired hemodynamic response to nitric oxide synthesis inhibition in diabetes is therefore not caused by a primary defect but rather due to altered vascular responsiveness secondary to long-standing disease.
AB - Background: An impaired ocular hemodynamic response to systemic nitric oxide synthesis inhibition has been demonstrated in patients with long-standing insulin-dependent diabetes mellitus. It is unclear whether this altered responsiveness is already detectable in early uncomplicated type I diabetes. Methods: The effect of the nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA) was studied in 10 male patients with early type I diabetes under euglycemic conditions and 10 healthy matched control subjects in a single (analyst) blinded cohort study design. Changes in ocular hemodynamics (fundus pulsation amplitude, mean flow velocity in the ophthalmic artery) and in pulse rate and mean blood pressure were measured in response to systemic intravenous doses of 1.5, 3, and 6 mg/kg L-NMMA. Results: L-NMMA dose-dependently and significantly decreased fundus pulsation amplitude (-21.0% vs -23.3% in diabetics and controls, respectively), mean flow velocity in the ophthalmic artery (-12.3% vs -10.8%) and pulse rate (-15.4% vs -16.6%) and increased mean arterial pressure (+19.5% vs +14.7%). The ocular and systemic hemodynamic effects of L-NMMA were not different between patients with diabetes and controls. Conclusion: The responsiveness of the choroidal vasculature and the ophthalmic artery to L-NMMA is not altered in early type 1 diabetes. An impaired hemodynamic response to nitric oxide synthesis inhibition in diabetes is therefore not caused by a primary defect but rather due to altered vascular responsiveness secondary to long-standing disease.
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U2 - 10.1007/s00417-003-0708-7
DO - 10.1007/s00417-003-0708-7
M3 - Article
C2 - 12836035
AN - SCOPUS:0141739301
SN - 0721-832X
VL - 241
SP - 619
EP - 624
JO - Graefe's Archive for Clinical and Experimental Ophthalmology
JF - Graefe's Archive for Clinical and Experimental Ophthalmology
IS - 8
ER -
