In biliary atresia (BA), a cholangiopathy of elusive etiology invariably leads to cirrhosis, and a disturbed angiogenesis may be involved. We evaluated the hepatobiliary immunolocalization of vascular endothelial growth factor (VEGF) A, VEGF receptor 1 (R1), and R2 in BA. We analyzed biopsies obtained at portoenterostomy from infants with BA (n=52), including embryonic (n=14) and perinatal (n=38) types. Controls were infants with intrahepatic cholestasis (IC; n=7). In BA, VEGF A immunolocalization was also evaluated in explants (n=33) and at the porta hepatis (n=16). We morphometrically assessed the percentage of CK7 (PCK7) positivity in BA and the ratio medial layer thickness/luminal diameter in hepatic artery branches in BA and IC. We found that arteries were more frequently positive for VEGF A in BA at portoenterostomy (P=0.006) than in other groups. In explants, VEGF A immunolocalization was mainly lobular (P<0.001). VEGFR2 was less frequently positive in BA than IC in bile ducts (P=0.023) and hepatocytes (P=0.011). A higher PCK7 positivity was associated with arterial (P<0.001) and biliary (P=0.040) VEGF A positivity. PCK7 was correlated with biliary (P=0.031), arterial (P=0.031), and hepatocytic (P=0.032) VEGF A positivity in BA at portoenterostomy. VEGF A was positive in arteries and bile ducts at the porta hepatis mainly in the perinatal BA type (P=0.013). Biliary (P=0.016) and arterial (P=0.044) VEGF A positivity were associated with higher ratio medial layer thickness/luminal diameter values. Our findings suggest that hypoxia/ischemia affects the portal structures in BA at portoenterostomy, beginning at the porta hepatis, and it is associated both with the extent of biliary proliferation and medial layer thickening.

Na+, K+-ATPase activity was measured in synaptic plasma membrane from cerebral cortex of Wistar rats subjected to experimental phenylketonuria, i.e., chemical hyperphenylalaninemia induced by subcutaneous administration of 5.2 micromol phenylalanine / g body weight (twice a day) plus 0.9 micromol p-chlorophenylalanine / g body weight (once a day). The treatment was performed from the 6th to the 14th postpartum day and rats were killed 12 h after the last injection. Synaptic plasma membrane from cerebral cortex was prepared by a discontinuous density sucrose gradient for Na+, K+-ATPase activity determination. The results showed that the enzyme activity was decreased by 30% in animals subjected to experimental phenylketonuria when compared to control. The in vitro effects of the drugs on Na+, K+-ATPase activity were also investigated. Phenylalanine and p-chlorophenylalanine inhibited the enzyme activity and this inhibition was reversed by alanine. In addition, competition between phenylalanine and p-chlorophenylalanine for binding to the enzyme was observed, suggesting a common binding site for these substances. Our results suggest that reduction of Na+, K+-ATPase activity may be one of the mechanisms related to the brain dysfunction observed in human PKU.