title: Creatine in the central nervous system: From magnetic resonance spectroscopy to creatine deficiencies.
abstract: Creatine (Cr) is an important organic compound acting as intracellular high-energy phosphate shuttle and in energy storage. While located in most cells where it plays its main roles in energy metabolism and cytoprotection, Cr is highly concentrated in muscle and brain tissues, in which Cr also appears to act in osmoregulation and neurotransmission. This review discusses the basis of Cr metabolism, synthesis and transport within brain cells. The importance of Cr in brain function and the consequences of its impaired metabolism in primary and secondary Cr deficiencies are also discussed. Cr and phosphocreatine (PCr) in living systems can be well characterized using in vivo magnetic resonance spectroscopy (MRS). This review describes how1H MRS allows the measurement of Cr and PCr, and how31P MRS makes it possible to estimate the creatine kinase (CK) rate constant and so detect dynamic changes in the Cr/PCr/CK system. Absolute quantification by MRS using creatine as internal reference is also debated. The use of in vivo MRS to study brain Cr in a non-invasive way is presented, as well as its use in clinical and preclinical studies, including diagnosis and treatment follow-up in patients.
authors.affiliation: Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
authors.forename: Veronika
authors.initials: V
authors.lastname: Rackayova
authors.affiliation: Centre d'Imagerie Biomedicale (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cudalbu
authors.affiliation: Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Petra J W
authors.initials: PJW
authors.lastname: Pouwels
authors.affiliation: Service of Biomedicine, Neurometabolic Unit, Lausanne University Hospital, Lausanne, Switzerland. Electronic address: Olivier.Braissant@chuv.ch.
authors.forename: Olivier
authors.initials: O
authors.lastname: Braissant
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D001927:Brain Diseases / Q000378:metabolism* / Q000473:pathology; D003401:Creatine / Q000172:deficiency* / Q000378:metabolism*; D004734:Energy Metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008954:Models, Biological
chemical_list: D003401:Creatine
keywords: (1)H MRS; (31)P MRS; Brain; Creatine; Creatine deficiencies; Guanidinoacetate