Nitric oxide plasma levels in patients with chronic and acute cerebrovascular disorders

The authors carried out a study on plasma level of nitrites, stable end-products of nitric oxide, aimed at investigating some features of the cerebral microvascular function in chronic and acute cerebrovascular disorders,

The series consists of 16 patients with chronic cerebral vascular disease, 11 patients with TIA, 28 patients with thrombotic stroke and 27 normal controls; the diagnosis was done on the basis of clinical, ultrasonographic and tomodensitometric findings. For each subject the determination of nitrate plasma levels by a method based on the colorimetric reaction (developed by nitrites dissolved in an acid solution containing sulfanilamide) was performed; this reaction yields quantitative results exactly corresponding to the amount of nitric oxide.

In chronic cerebrovascular patients NO2-values tendentially higher (16.4 +/- 0.52 mumol/l) but not statistically different from those of controls (13.2 +/- 0.52) were obtained; also the values found in the group with TIA, even if slightly reduced (8.0 +/- 1.4 mumol/l), did not differ from controls; in the stroke group a significant (p < 0.05) reduction (6.4 +/- 0.52 mumol/l), as compared to controls, was found.

On the basis of these results and of the literature data on the physiopathological profile of NO, the authors suggest a compensatory increase of the basal tone of NO in chronic cerebrovascular diseases, while an impaired endothelial synthesis of the marker could play a critical role in TIA patients and more evidently in stroke patients, presenting a wide microvascular area completely and irreversibly excluded.