title: High Protein Diet and Huntington's Disease.
abstract: Huntington's disease (HD) is a neurodegenerative disorder caused by the huntingtin (HTT) gene with expanded CAG repeats. In addition to the apparent brain abnormalities, impairments also occur in peripheral tissues. We previously reported that mutant Huntingtin (mHTT) exists in the liver and causes urea cycle deficiency. A low protein diet (17%) restores urea cycle activity and ameliorates symptoms in HD model mice. It remains unknown whether the dietary protein content should be monitored closely in HD patients because the normal protein consumption is lower in humans (~15% of total calories) than in mice (~22%). We assessed whether dietary protein content affects the urea cycle in HD patients. Thirty HD patients were hospitalized and received a standard protein diet (13.7% protein) for 5 days, followed by a high protein diet (HPD, 26.3% protein) for another 5 days. Urea cycle deficiency was monitored by the blood levels of citrulline and ammonia. HD progression was determined by the Unified Huntington's Disease Rating Scale (UHDRS). The HPD increased blood citrulline concentration from 15.19 μmol/l to 16.30 μmol/l (p = 0.0378) in HD patients but did not change blood ammonia concentration. A 2-year pilot study of 14 HD patients found no significant correlation between blood citrulline concentration and HD progression. Our results indicated a short period of the HPD did not markedly compromise urea cycle function. Blood citrulline concentration is not a reliable biomarker of HD progression.
authors.affiliation: Department of Neurology, Chang Gung Memorial Hospital, Linkou Medical Center and College of Medicine, Chang-Gung University, Taoyuan, Taiwan.
authors.forename: Chiung-Mei
authors.initials: CM
authors.lastname: Chen
authors.affiliation: Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Yow-Sien
authors.initials: YS
authors.lastname: Lin
authors.affiliation: Department of Neurology, Chang Gung Memorial Hospital, Linkou Medical Center and College of Medicine, Chang-Gung University, Taoyuan, Taiwan.
authors.forename: Yih-Ru
authors.initials: YR
authors.lastname: Wu
authors.affiliation: Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Pei
authors.initials: P
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, Medical Research and Medical Genetics, China Medical University Hospital, Taichung, 404, Taiwan.
authors.forename: Fuu-Jen
authors.initials: FJ
authors.lastname: Tsai
authors.affiliation: Department of Dietetics and Nutrition, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chueh-Lien
authors.initials: CL
authors.lastname: Yang
authors.affiliation: Department of Nutrition, Chang Gung Memorial Hospital, Linkou Medical Center and College of Medicine, Chang-Gung University, Taoyuan, Taiwan.
authors.forename: Ya-Tzu
authors.initials: YT
authors.lastname: Tsao
authors.affiliation: Department of Dietetics and Nutrition, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Wen
authors.initials: W
authors.lastname: Chang
authors.affiliation: Department of Nutrition, Chang Gung Memorial Hospital, Linkou Medical Center and College of Medicine, Chang-Gung University, Taoyuan, Taiwan.
authors.forename: I-Shan
authors.initials: IS
authors.lastname: Hsieh
authors.affiliation: Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors.forename: Yijuang
authors.initials: Y
authors.lastname: Chern
authors.affiliation: Department of Neurology, Yang-Ming University School of Medicine and Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Bing-Wen
authors.initials: BW
authors.lastname: Soong
mesh_terms: D000328:Adult; D002956:Citrulline / Q000097:blood; D004044:Dietary Proteins / Q000008:administration & dosage*; D018450:Disease Progression; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000097:blood / Q000503:physiopathology*; D008297:Male; D014508:Urea / Q000378:metabolism
chemical_list: D004044:Dietary Proteins; D002956:Citrulline; D014508:Urea