筋萎縮性側索硬化症の代謝異常と栄養療法

抄録

Weight loss is frequently observed in early–stage amyotrophic lateral sclerosis (ALS) and is considered an independent predictor of survival. Weight loss observed in ALS is associated with multifactorial etiology, including muscle wasting and dysphagia ; however, recent studies have implicated disease–specific hypermetabolism in weight loss and disease progression in ALS. The pathophysiology of hypermetabolism as a contributor to weight loss in ALS remains unclear ; however, hypothalamic involvement is considered an early extra–motor manifestation of ALS. TDP–43 protein aggregates detected in the hypothalamic subnuclei may be associated with weight loss or abnormalities of eating behavior in patients with ALS. Weight loss from diagnosis up to tracheostomy also predicts functional prognosis during the long–term period with ventilator. In fact, patients with ALS who survive with prolonged mechanical ventilatory support often develop significant brain and brainstem atrophy, including atrophy of the limbic motor system and the hypothalamus. Nutritional intervention to maintain body weight may be a useful disease–modifying therapeutic approach, and recent studies have reported that slowing of weight reduction rate after diagnosis may be associated with better survival and that a high–calorie diet improves survival in patients with rapidly progressive disease. Nutritional education regarding a high–calorie diet, weight control, and early gastric tube placement are important after diagnosis. Researchers from the USA, Europe, and Japan have established formulas to estimate the recommended daily energy intake. Although a lipid shift in energy metabolism might occur in the brain and muscles in patients with ALS, the effectiveness of high–fat diets requires further investigation.