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L-Arginine Minimises Stroke Damage in Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like Episodes: Presented at ANA

By Thomas S. May
Special to DG News

NEW YORK, NY -- October 16, 2002 -- L-arginine therapy minimises tissue injury from ischaemia in the acute phase of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS).

This is the conclusion of a study presented here October 15 at the 127^th annual meeting of the American Neurological Association (ANA), by Dr. Yasutoshi Koga, from the department of paediatrics and child health, Kurume University School of Medicine, in Kurume, Fukuoka, Japan.

People afflicted with MELAS are vulnerable to small strokes during childhood and early adulthood. Based on the assumption that such strokes are caused by impairment of vasodilation in some segment of the intracerebral artery, the researchers administered L-arginine, a drug that helps control the expansion of blood vessels, to patients with MELAS in the acute phase of stroke.

Patients received 0.5gm/kg L-arginine in a 10 percent solution in six separate stroke-like episodes, and a placebo in another six episodes. The investigators analysed clinical symptoms, biochemical parameters, and intracranial haemodynamics by computed tomography before and after treatment.

They found that 30 minutes after L-arginine administration, all of the symptoms -- except teichopsia -- improved drastically.

There was also significantly increased uptake in the infarcted region compared with the contralateral regions, showing improvement in regional cerebral blood flow in the region of the fresh infarct. Levels of lactate and lactate/pyruvate ratio recovered to steady state levels 24 hours after L-arginine administration.

The investigators concluded that L-arginine therapy improved microcirculation in the infarcted region and reduced tissue injury from ischaemia. L-arginine is the first drug that has been shown to rescue MELAS patients from the acute symptoms of stroke, the researchers contend.

"L-Arginine therapy also improved the blood flow in the area of the stroke, reducing tissue damage, and therefore constitutes a new potential therapy for use in the acute phase of stroke-like episodes in MELAS," Dr. Koga noted.

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