L-carnitine blood levels and oxidative stress in treated phenylketonuric patients.
OBJECTIVE
L-carnitine exerts an important role by facilitating the mitochondrial transport of fatty acids, but is also a scavenger of free radicals, protecting cells from oxidative damage. Phenylketonuria (PKU), an inborn error of phenylalanine (Phe) metabolism, is currently treated with a special diet consisting of severe restriction of protein-enriched foods, therefore potentially leading to L-carnitine depletion. The aim of this study was to determine L-carnitine levels and oxidative stress parameters in blood of two groups of PKU patients, with good and poor adherence to treatment.


METHODS
Treatment of patients consisted of a low protein diet supplemented with a synthetic amino acids formula not containing Phe, L-carnitine, and selenium. L-carnitine concentrations and the oxidative stress parameters thiobarbituric acid reactive species (TBARS) and total antioxidant reactivity (TAR) were measured in blood of the two groups of treated PKU patients and controls.


RESULTS
We verified a significant decrease of serum L-carnitine levels in patients who strictly adhered to the diet, as compared to controls and patients who did not comply with the diet. Furthermore, TBARS measurement was significantly increased and TAR was significantly reduced in both groups of phenylketonuric patients relatively to controls. We also found a significant negative correlation between TBARS and L-carnitine levels and a significant positive correlation between TAR and L-carnitine levels in well-treated PKU patients.


CONCLUSIONS
Our results suggest that L-carnitine should be measured in plasma of treated PKU patients, and when a decrease of this endogenous component is detected in plasma, supplementation should be considered as an adjuvant therapy.
Sitta
Angela
A
Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Ramiro Barcelos 2700, Porto Alegre, RS 90035-003, Brazil.
Barschak
Alethéa G
AG
Deon
Marion
M
de Mari
Jurema F
JF
Barden
Amanda T
AT
Vanzin
Camila S
CS
Biancini
Giovana B
GB
Schwartz
Ida V D
IV
Wajner
Moacir
M
Vargas
Carmen R
CR
D000293:Adolescent; D002331:Carnitine / Q000032:analysis / Q000097:blood* / Q000172:deficiency*; D002648:Child; D018753:Diet, Protein-Restricted; D019587:Dietary Supplements / Q000592:standards; D015536:Down-Regulation / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D018384:Oxidative Stress / Q000502:physiology*; D010661:Phenylketonurias / Q000097:blood* / Q000178:diet therapy / Q000503:physiopathology; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis / Q000378:metabolism
D017392:Thiobarbituric Acid Reactive Substances; D002331:Carnitine