Carnitine supplementation in progressive supranuclear palsy.

Abstract

Mitochondrial dysfunction has been implicated in the pathogenesis of several neurodegenerative disorders, including progressive supranuclear palsy (PSP). PSP is a Parkinsonian syndrome characterized by a rapidly progressive state that manifests itself as tremors, bradykinesia, and supranuclear gaze palsy. Carnitine plays an essential role in mitochondrial function by transporting fatty acids across the mitochondrial membrane to be used in energy production. Mitochondrial dysfunction can bring about rapid neuronal depolarization and a calcium-mediated cellular apoptosis owing to a loss of oxidative metabolism, likely contributing to the PSP disease process. A White man aged 65 years with PSP presented with small bowel obstruction and severe malnutrition as a result of prior gastrointestinal surgeries for which a gastrostomy tube was placed. During his hospitalization, the patient was found to be deficient in both free and total carnitine. He was treated with levocarnitine supplementation and exhibited marked improvement in tremors, fatigue, and physical therapy activities. Posthospitalization follow-up showed sustained improvement in symptoms with continued levocarnitine supplementation. Treatment of PSP remains largely supportive in nature. No studies have investigated the role of carnitine supplementation in PSP. To our knowledge, this is the first case report to identify improvement in PSP symptoms after carnitine repletion and supportive care. Numerous animal studies have reported on carnitine supplementation in the context of mitochondrial dysfunction associated with neurodegenerative diseases, such as Parkinson disease and Alzheimer disease. Further investigation is necessary to elucidate the precise role of carnitine and other nutrition supplements in the pathophysiology of PSP.