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Teraishi T, Kajiwara M, Hori H, Sasayama D, Hidese S, Matsuo J, Ishida I, Kajiwara Y, Ozeki Y, Ota M, Hattori K, Higuchi T, Kunugi H. 13C-phenylalanine breath test and serum biopterin in schizophrenia, bipolar disorder and major depressive disorder. J Psychiatr Res 2018; 99:142-150. [PMID: 29454221 DOI: 10.1016/j.jpsychires.2018.01.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 12/23/2017] [Accepted: 01/26/2018] [Indexed: 10/18/2022]
Abstract
Phenylalanine is required for the synthesis of the neurotransmitters dopamine, noradrenaline, and adrenaline. The rate-limiting step for phenylalanine metabolism is catalyzed by phenylalanine hydroxylase (PAH) and its cofactor tetrahydrobiopterin. We aimed to detect altered phenylalanine metabolism in major psychiatric disorders using the l-[1-13C]phenylalanine breath test (13C-PBT) and serum biopterin levels. We also investigated association of PAH mutations with schizophrenia and phenylalanine metabolism. 13C-phenylalanine (100 mg) was orally administered, and the breath 13CO2/12CO2 ratio was monitored for 120 min in four groups: 103 patients with schizophrenia (DSM-IV), 39 with bipolar disorder, 116 with major depressive disorder (MDD), and 241 healthy controls. Serum biopterin levels were measured by high performance liquid chromatography. Mutation screening of PAH exons was performed by direct sequencing in 46 schizophrenia patients. Association analysis was performed using six tag single nucleotide polymorphisms and the PAH Arg53His mutation by TaqMan assays in 616 schizophrenia patients and 1194 healthy controls. Analyses of covariance controlling for age, sex, and body weight showed that the index for the amount of exhaled 13CO2 was significantly lower in the schizophrenia group than in the other three groups (all p < 0.05). Biopterin levels in schizophrenia and MDD were significantly lower than those in controls. Biopterin levels correlated with 13C-PBT indices in controls. PAH polymorphisms were not associated with schizophrenia or 13C-PBT indices. 13C-PBT revealed reduced phenylalanine metabolism in schizophrenia, though we obtained no evidence of involvement of PAH polymorphism. Serum biopterin levels were lower in schizophrenia and MDD, warranting further investigation.
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Affiliation(s)
- Toshiya Teraishi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan
| | - Masahiro Kajiwara
- Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa, 245-0066, Japan; Tri-X Biomedical, Inc., 4-12-5-406, Minamiyawata, Ichikawa, Chiba, 272-0023, Japan
| | - Hiroaki Hori
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan
| | - Daimei Sasayama
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan
| | - Shinsuke Hidese
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan
| | - Junko Matsuo
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan
| | - Ikki Ishida
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan
| | - Yasuhiro Kajiwara
- Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama, Kanagawa, 245-0066, Japan
| | - Yuji Ozeki
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan; Department of Psychiatry, Dokkyo Medical University School of Medicine, Tochigi, 321-0293, Japan
| | - Miho Ota
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan
| | - Kotaro Hattori
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan
| | - Teruhiko Higuchi
- National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8551, Japan
| | - Hiroshi Kunugi
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1, Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan.
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