title: Carnitine and/or Acetylcarnitine Deficiency as a Cause of Higher Levels of Ammonia.
abstract: Blood carnitine and/or acetylcarnitine deficiencies are postulated in the literature as possible causes of higher ammonia levels. The aim of this study was to investigate if the use of valproic acid, the age of the patients, or certain central nervous system pathologies can cause carnitine and/or acetylcarnitine deficiency leading to increased ammonia levels. Three groups of patients were studied: (A) epileptic under phenytoin monotherapy (n = 31); (B) with bipolar disorder under valproic acid treatment (n = 28); (C) elderly (n = 41). Plasma valproic acid and blood carnitine and acyl carnitine profiles were determined using a validated HPLC and LC-MS/MS method, respectively. Blood ammonia concentration was determined using an enzymatic automated assay. Higher ammonia levels were encountered in patients under valproic acid treatment and in the elderly. This may be due to the lower carnitine and/or acetylcarnitine found in these patients. Patients with controlled seizures had normal carnitine and acetylcarnitine levels. Further studies are necessary in order to conclude if the uncontrolled bipolar disorder could be the cause of higher carnitine and/or acetylcarnitine levels.
authors.affiliation: Pharmaceutical Sciences Department, Faculty of Chemistry, Universidad de la República, Avenida General Flores 2124, P.O. Box 1157, 11800 Montevideo, Uruguay.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Maldonado
authors.affiliation: Pharmaceutical Sciences Department, Faculty of Chemistry, Universidad de la República, Avenida General Flores 2124, P.O. Box 1157, 11800 Montevideo, Uruguay.
authors.forename: Natalia
authors.initials: N
authors.lastname: Guevara
authors.affiliation: Newborn Screening Laboratory, Social Security Institute, Tristán Narvaja 1716, 11200 Montevideo, Uruguay.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Queijo
authors.affiliation: Toxicology Department, Hospital de Clínicas, Universidad de la República, Avenida Italia s/n, 11609 Montevideo, Uruguay.
authors.forename: Raquel
authors.initials: R
authors.lastname: González
authors.affiliation: Pharmaceutical Sciences Department, Faculty of Chemistry, Universidad de la República, Avenida General Flores 2124, P.O. Box 1157, 11800 Montevideo, Uruguay.
authors.forename: Pietro
authors.initials: P
authors.lastname: Fagiolino
authors.affiliation: Pharmaceutical Sciences Department, Faculty of Chemistry, Universidad de la República, Avenida General Flores 2124, P.O. Box 1157, 11800 Montevideo, Uruguay.
authors.forename: Marta
authors.initials: M
authors.lastname: Vázquez
mesh_terms: D000108:Acetylcarnitine / Q000097:blood / Q000172:deficiency; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000641:Ammonia / Q000097:blood*; D001714:Bipolar Disorder / Q000097:blood / Q000188:drug therapy; D002331:Carnitine / Q000097:blood / Q000172:deficiency; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010672:Phenytoin / Q000008:administration & dosage*; D014635:Valproic Acid / Q000008:administration & dosage*
chemical_list: D014635:Valproic Acid; D010672:Phenytoin; D000108:Acetylcarnitine; D000641:Ammonia; D002331:Carnitine