title: Increased plasma agmatine levels in patients with schizophrenia.
abstract: Agmatine is an endogenous substance, synthesized from l-arginine, and it is proposed to be a new neurotransmitter. Preclinical studies indicated that agmatine may have an important role in the pathophysiology of schizophrenia. This study was organized to investigate plasma agmatine in patients with schizophrenia and in healthy controls. Eighteen patients with schizophrenia and 19 healthy individuals constituted the subjects. Agmatine levels in the plasma were measured using the HPLC method. The S100B protein level, which is a peripheral biomarker for brain damage, was also measured using the ELISA method. While plasma levels of agmatine in patients with schizophrenia were significantly increased (p < 0.0001) compared to those of healthy individuals (control), there were no significant changes in the levels of S100B protein (p = 0.660). An ROC (receiver operating characteristic) curve analysis revealed that measuring plasma agmatine levels as a clinical diagnostic test would significantly differentiate between patients with schizophrenia and those in the control group (predictive value: 0.969; p < 0.0001). The predictive value of S100B measurements was not statistically significant (p > 0.05). A multiple regression analysis revealed that the age of the patient and the severity of the illness, as indicated by the PANSS score, significantly contributed the plasma agmatine levels in patients with schizophrenia. These results support the hypothesis that an excess agmatine release is important in the development of schizophrenia. The findings also imply that the plasma agmatine level may be a potential biomarker of schizophrenia.
authors.affiliation: Uskudar University, Neuropsychopharmacology Application and Research Center, Istanbul, Turkey. tayfunuzbay@yahoo.com
authors.forename: Tayfun
authors.initials: T
authors.lastname: Uzbay
authors.forename: Gokhan
authors.initials: G
authors.lastname: Goktalay
authors.forename: Hakan
authors.initials: H
authors.lastname: Kayir
authors.forename: Salih S
authors.initials: SS
authors.lastname: Eker
authors.forename: Asli
authors.initials: A
authors.lastname: Sarandol
authors.forename: Sema
authors.initials: S
authors.lastname: Oral
authors.forename: Levent
authors.initials: L
authors.lastname: Buyukuysal
authors.forename: Gokhan
authors.initials: G
authors.lastname: Ulusoy
authors.forename: Selcuk
authors.initials: S
authors.lastname: Kirli
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000376:Agmatine / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D055664:Electrochemical Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012559:Schizophrenia / Q000097:blood*; D018709:Statistics, Nonparametric; D014421:Turkey; D055815:Young Adult
chemical_list: D000376:Agmatine