title: CSF/plasma ratios of amino acids: reference data and transports in children.
abstract: OBJECTIVE
  We intended to investigate the effects of age, gender, and medications on amino acid cerebrospinal fluid (CSF)/plasma ratios in children, and to determine whether amino acid transports across the blood-CSF barrier in children differ from those in adults.
  
  
  METHODS
  Amino acid concentrations measured by ion-exchange high-performance liquid chromatography were used (CSF from 99 children, simultaneously collected plasma from 76 children). Influence of age, gender, and medications on the amino acid CSF concentrations and CSF/plasma ratios were analyzed by linear multiple regression. Interactions of amino acid transports were analyzed by correlation analysis of CSF/plasma ratios.
  
  
  RESULTS
  CSF/plasma ratios of serine, valine, histidine, and arginine were higher in younger children. The glutamate CSF/plasma ratio was higher in older children. Serine, alanine, threonine, valine, and histidine CSF/plasma ratios were lower in females. Glutamine, methionine, tyrosine, and phenylalanine CSF/plasma ratios were elevated with valproate therapy. Serine, threonine, valine, leucine, and tyrosine CSF/plasma ratios were lower with clobazam therapy. The asparagine CSF/plasma ratio was elevated with pyridoxal phosphate therapy. Transports of most essential neutral amino acids interacted with each other, as did neutral amino acids with low molecular weights. Cationic amino acids interacted with each other and some essential neutral amino acids. Acidic amino acids had no interactions with other amino acids.
  
  
  CONCLUSIONS
  Age, gender, and anti-epileptic drugs affect amino acid CSF/plasma ratios in children. Transport interactions between amino acids in children showed no remarkable difference from those of adults and generally followed the substrate specificities of multiple amino acid transport systems.
authors.affiliation: Department of Child Neurology, Okayama University Hospital, Okayama, Japan. Electronic address: takiyama@okayama-u.ac.jp.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Akiyama
authors.affiliation: Department of Child Neurology, Okayama University Hospital, Okayama, Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Central Clinical Laboratory, Okayama University Hospital, Okayama, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Higashikage
authors.affiliation: Central Clinical Laboratory, Okayama University Hospital, Okayama, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Sato
authors.affiliation: Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Yoshinaga
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000596:Amino Acids / Q000097:blood* / Q000134:cerebrospinal fluid*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D002658:Developmental Disabilities / Q000097:blood* / Q000134:cerebrospinal fluid* / Q000188:drug therapy; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D008297:Male; D012016:Reference Values; D012044:Regression Analysis; D012189:Retrospective Studies; D012737:Sex Factors
chemical_list: D000596:Amino Acids
keywords: Blood–CSF barrier; Blood–brain barrier; Reference values; Transport systems