RESULTS: No significant differences in hepatic MRP2 expression level were observed between BA and controls groups. There was no correlation between MRP2 expression and age at time of surgery in BA and control groups. In BA patients, MRP2 expression level in the
jaundice and
jaundice-free group did not differ significantly (2.0 × 10-4 vs 3.1 × 10-4, p = 0.094). Although the serum level of total
bilirubin just before surgery did not correlate with MRP2 expression level (rs = 0.031, p = 0.914), the serum level of total
bilirubin measured at 2 weeks (rs = -0.569, p = 0.034) and 4 weeks after surgery (rs = -0.620, p = 0.018) were significantly correlated with MRP2 expression level. Furthermore, MRP2 expression level was inversely correlated with ratio of change in serum total
bilirubin level over 4 weeks (rs = -0.676, p = 0.008), which represents the serum
bilirubin level measured at 4 weeks after surgery divided by value just before surgery. There was no correlation between expression level of MRP2 and
nuclear receptors, such as
retinoid × receptor α, farnesoid × receptor, pregnane × receptor, or
constitutive androstane receptor.
CONCLUSIONS: Hepatic MRP2 expression level was associated with postoperative clearance of
jaundice in BA patients, at least within 1 month after
hepatoportoenterostomy. This finding suggests that not only morphological appearance of the liver tissue but also the
biological status of hepatocytes is important for BA pathophysiology.