title: Serum retinol binding protein 4 and clinical outcome in postoperative biliary atresia.
abstract: BACKGROUND
  Biliary atresia (BA), a chronic inflammatory disease of bile ducts, is characterized by the obliteration of bile flow. The aim of the present study was to investigate serum retinol binding protein 4 (RBP4) in postoperative BA patients and the association of RBP4 with clinical parameters and liver stiffness scores.
  
  
  METHODS
  A number of forty-eight BA patients post Kasai operation and 24 controls were enrolled. None of the patients had undergone liver transplantation. BA patients were classified into two groups according to their serum total bilirubin (TB) levels (non-jaundice, TB < 2 mg/dl vs. jaundice, TB ≥ 2 mg/dl) and liver stiffness (insignificant fibrosis, liver stiffness <7 kPa vs. significant fibrosis, liver stiffness ≥7 kPa). Serum RBP4 levels were determined by enzyme-linked immunosorbent assay (ELISA). Liver stiffness scores were measured by FibroScan.
  
  
  RESULTS
  BA patients had lower RBP4 levels (14.9 ± 1.0 vs. 18.7 ± 1.0 ng/ml, P = 0.02), but higher liver stiffness than controls (29.5 ± 3.3 vs. 5.0 ± 0.5 kPa, P < 0.001). Serum RBP4 levels were significantly decreased in BA patients with jaundice, compared with those without jaundice (9.5 ± 0.9 vs. 18.2 ± 1.2 ng/ml, P < 0.001). Moreover, BA patients with significant liver fibrosis displayed lower serum RBP4 than those with insignificant fibrosis (14.1 ± 1.2 vs. 21.2 ± 1.4 ng/ml, P = 0.02). Further analysis showed that serum RBP4 was strongly correlated with liver stiffness and serum albumin (r = -0.72, P < 0.001, and r = 0.65, P < 0.001, respectively). BA patients with portal hypertension (PH) had lower serum RBP4 than those without PH (12.8 ± 1.2 vs. 19.2 ± 1.7 ng/ml, P = 0.003).
  
  
  CONCLUSIONS
  Serum RBP4 levels decreased in BA patients compared with normal participants, and its levels declined significantly in patients with more severe disease. RBP4 may play a role in the pathogenesis of hepatic fibrosis and serve as a possible biomarker reflecting disease severity in postoperative BA patients.
authors.affiliation: Department of Physiology, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand.
authors.forename: Maneerat
authors.initials: M
authors.lastname: Chayanupatkul
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand. sittisak.h@chula.ac.th.
authors.forename: Sittisak
authors.initials: S
authors.lastname: Honsawek
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Centre of Excellence in Clinical Virology, Chulalongkorn University, Bangkok, 10330, Thailand.
authors.forename: Voranush
authors.initials: V
authors.lastname: Chongsrisawat
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Centre of Excellence in Clinical Virology, Chulalongkorn University, Bangkok, 10330, Thailand.
authors.forename: Linda
authors.initials: L
authors.lastname: Vimolket
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Centre of Excellence in Clinical Virology, Chulalongkorn University, Bangkok, 10330, Thailand.
authors.forename: Yong
authors.initials: Y
authors.lastname: Poovorawan