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Published on: December 16, 2021
[L-arginine therapy on MELAS]
1Department of Pediatrics and Child Health, Kurume University School of Medicine.
Abstract:
MELAS is the most dominant clinical features among mitochondrial disorders. However the natural course of MELAS has not been clarified yet. In order to elucidate the natural course of MELAS, we have done the Japanese Cohort study on MELAS. By the age of onset, we divided MELAS into two subgroups, a juvenile form (onset is less than 18 years of age) and an adult form (onset is more than 18 years of age). Juvenile form is significantly different from adult form not only in the mean age of onset, but the mean age of death and survival rate (juvenile has 3.2 times higher chance of death than adult). Our date indicate that juvenile form of MELAS is more severe and poor prognosis than those seen in adult form. Based on the hypothesis that MELAS is caused by impaired vasodilation in an intracerebral artery, we evaluated the effects of administering L-arginine, a nitric oxide precursor. Patients were administered L-arginine intravenously at acute phase, or per orally at interictal phase. L-arginine infusions significantly improved all stroke-like symptoms suggesting stroke within 30 min, and oral administration significantly decreased frequency and severity of stroke-like episodes. L-arginine therapy showed promise in treating stroke-like episodes in MELAS.
Insights
Juvenile Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) is more severe with a poorer prognosis than adult-onset MELAS. L-arginine shows promise in treating stroke-like episodes in MELAS patients.
Area of Science:
- Mitochondrial Medicine
- Neurology
- Genetics
Context:
- Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) is a significant mitochondrial disorder.
- The natural history and prognostic factors of MELAS remain incompletely understood.
- Distinguishing between juvenile and adult-onset MELAS is crucial for understanding disease trajectory.
Purpose:
- To elucidate the natural course of MELAS by analyzing a Japanese cohort.
- To compare the clinical characteristics and outcomes of juvenile-onset versus adult-onset MELAS.
- To investigate the therapeutic potential of L-arginine in managing MELAS-related stroke-like episodes.
Summary:
- The Japanese Cohort study on MELAS identified distinct differences between juvenile (onset <18 years) and adult (onset >18 years) forms.
- Juvenile MELAS exhibits a significantly earlier age of onset, earlier age of death, and a 3.2 times higher mortality rate compared to adult MELAS.
- Intravenous or oral administration of L-arginine, a nitric oxide precursor, demonstrated significant improvements in stroke-like symptoms and reduced their frequency and severity.
Impact:
- This study highlights the more severe prognosis of juvenile MELAS, emphasizing the need for early intervention and tailored management strategies.
- L-arginine therapy presents a promising treatment option for mitigating the debilitating stroke-like episodes characteristic of MELAS.
- Findings contribute to a better understanding of MELAS natural history and potential therapeutic targets, improving patient outcomes.
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