Adiponectin (Adpn), an adipose tissue-derived
hormone, prevents endothelial
inflammation and early
atherogenesis. Classic
phenylketonuria (PKU), an inborn error of
phenylalanine (Phe) metabolism, results in a reduction of
catecholamine biosynthesis and requires treatment with lifelong low-Phe diet to prevent mental dysfunction and allow proper intellectual development. In this study, we evaluated the effect of the quality of PKU diet on plasma Adpn concentrations and related biochemical indices of endothelial dysfunction and
atherogenesis. Patients with PKU were divided into groups A (n = 18), who were on a strict diet, and B (n = 18), who were on a loose diet, after evaluation of their 30-day dietetic diaries and measurement of Phe blood concentrations. Twenty healthy children of similar ages and body mass indexes served as controls (group C). Group A patients had normal circulating
catecholamines and Adpn and decreased
tumor necrosis factor alpha concentrations and
low-density lipoprotein cholesterol/
apolipoprotein B ratio compared with groups B and C. Despite these favorable parameters, however,
homocysteine concentration was twice as high in group A compared with groups B and C. Interestingly, group B patients under loose dietary control had significantly elevated Adpn concentrations compared with groups A and C and increased
tumor necrosis factor alpha and an unfavorable
lipid profile, but normal levels of
homocysteine. These data support the hypothesis that
catecholamines inhibit Adpn secretion and that the elevated Adpn of the poorly controlled patients might moderate their risk for endothelial dysfunction and
atherogenesis.
Homocysteine production appears to be unfavorably affected by a strict PKU diet, diverging from the rest of the
atherogenesis risk factors, which were improved in the well-controlled patients.