کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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6223697 | 1607469 | 2013 | 5 صفحه PDF | دانلود رایگان |
ObjectiveTo determine whether levels of melatonin in blood and urine can serve as a peripheral biomarker to reflect brain serotonin synthesis in individuals with phenylketonuria (PKU).Study designWe measured the levels of melatonin, a serotonin metabolite in the pinealocytes, in the blood and urine of individuals with PKU in a randomized double-blind placebo controlled crossover study consisting of three 3-week phases in 10 adults with PKU: phase 1 (washout), phase 2 (supplementation of large neutral amino acid [LNAA] tablets or placebo), and phase 3 (alternate supplementation). An overnight protocol to measure blood melatonin and urine 6-sulfatoxymelatonin and dopamine in first void urine specimens was conducted after each phase for subjects with PKU and once in 10 controls.ResultsSignificantly lower concentrations of these neurotransmitter metabolites were observed in subjects with PKU after phase 1 compared with controls (serum melatonin PÂ =Â .008, urine melatonin PÂ =Â .0043, urine dopamine PÂ <Â .0001), with significant increases after LNAA supplementation compared with the placebo phase (serum melatonin PÂ =Â .0008, urine melatonin PÂ =Â .0008, urine dopamine PÂ =Â .0005). The mean tryptophan/LNAA and tyrosine/LNAA ratios were markedly lower in subjects with PKU compared with controls, and these ratios were significantly increased in the LNAA phase compared with the placebo phase (PÂ =Â .016, PÂ =Â .0003, respectively). Blood phenylalanine levels in subjects with PKU were not significantly different between placebo and LNAA phases (PÂ =Â .74).ConclusionBlood and urine melatonin levels may serve as biomarkers reflecting brain serotonin synthesis in subjects with PKU. Because this cannot be evaluated using blood phenylalanine levels, it may provide information on neurotransmitter metabolism for optimal dietary management.
Journal: The Journal of Pediatrics - Volume 162, Issue 5, May 2013, Pages 999-1003