Metabolic and catecholamine response to sympathetic stimulation in early-treated adult male patients with phenylketonuria

Abstract

Purpose Defective function of phenylalanine hydroxylase in phenylketonuria (PKU) results in the accumulation of phenylalanine (Phe) and the reduction of tyrosine (Tyr) in the blood, interfering in the normal development and function of organs and tissues in the body. Tyr is the precursor of catecholamines, secreted in response to stress by the adrenal medulla and paraganglia. The aim of this study was to evaluate plasma catecholamine and amino acid response to an escalating series of sympathetic stress tests in PKU patients. Methods Twelve males with classical PKU (aged 18–41 years) and ten healthy male controls were included in this study. The subjects were exposed to three different sympathetic stress stimulations: cold pressor, isometric handgrip, and peak treadmill tests to exhaustion. Physiological, metabolic, and hormonal changes were determined. Results Aerobic capacity (VO 2max ) was significantly lower in the PKU group ( p = 0.018); however, relative VO 2max was similar in the two groups during the spiroergometric test. No significant differences in norepinephrine or in epinephrine response were found between the two groups during the different stimulation tests. Blood Phe increased significantly in the PKU group compared with controls ( p = 0.027) during the spiroergometric test, while Tyr levels remained stable in both groups. Conclusion PKU itself might not influence stress-induced catecholamine changes. Only strenuous exercise increased blood Phe levels in PKU subjects.

Reduced macular thickness and macular vessel density in early-treated adult patients with PKU

“…Phenylalanine and tyrosine levels were measured by API2000 LC/MS/MS (Perkin-Elmer Sciex, Ontario, Canada) at the 1st Department of Pediatrics, Semmelweis University, Budapest from antecubital blood samples under standardized circumstances in compliance with the recommendations of the European guideline for adult patients with PKU. The analytical methods have been previously described [ 42 ].…”

Altered visual functions, macular ganglion cell and papillary retinal nerve fiber layer thickness in early-treated adult PKU patients

“…Phenylalanine and tyrosine levels were measured by API2000 LC/MS/MS (Perkin-Elmer Sciex, Ontario, Canada) at the 1st Department of Pediatrics, Semmelweis University, Budapest. The analysis was performed according to methods previously described [ 30 ].…”

Protein status in phenylketonuria: A scoping review

“…Three studies included functional assessments of protein status, with one study specifically related to muscle strength [43] and two studies including assessments of physical performance [71,79] (Table 3). One study was cross-sectional in design [43], and the other two studies did not state the study designs but were interventional according to the methodology.…”

“…One study was cross-sectional in design [43], and the other two studies did not state the study designs but were interventional according to the methodology. All studies included adolescents and adults with PKU, and made comparisons to healthy controls [71,79] or reference population data [43] (Table 2). 3).…”