title: The expression of hepatic carboxypeptidase E is decreased in patients with cholesterol gallstone.
abstract: OBJECTIVE
  Decreased carboxypeptidase E (CPE) expression is associated with numerous pathophysiological conditions. This study aimed to investigate the potential function of hepatic CPE in cholesterol gallstone formation.
  
  
  METHODS
  Patients with cholesterol gallstone (CGS group) and patients without cholesterol gallstones (non-CGS group) were enrolled. The serum total cholesterol, triglyceride, and biliary composition were analyzed. Eight liver samples from two patients without CGS and six patients with CGS were subjected to cDNA microarray analysis. Hepatic CPE expression was detected by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and immunohistochemical analysis. Plasma CCK level was measured by ELISA.
  
  
  RESULTS
  cDNA microarray identified CPE as a gene downregulated in the CGS group. RT-PCR showed that CPE mRNA level was lower in CGS group than in control (P < 0.05, t-test). Moreover, Western blot and immunohistochemistry analysis showed that CPE protein level was significantly lower in CGS group than in the control group. In addition, plasma CCK level was lower in CGS group than in the control group. A positive correlation was found between serum CCK level and hepatic CPE mRNA level (r2 = 0.713, P = 0.003).
  
  
  CONCLUSIONS
  Down-expression of liver CPE may reduce the secretion of serum CCK and contribute to the formation of cholesterol gallstone.
authors.forename: Shu-Long
authors.initials: SL
authors.lastname: Dai
authors.forename: Jin
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of General Surgery, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China.
authors.forename: Kun-Xing
authors.initials: KX
authors.lastname: Yang
authors.forename: Shi-Yong
authors.initials: SY
authors.lastname: Yang
mesh_terms: D043423:Carboxypeptidase H / Q000235:genetics / Q000378:metabolism*; D016022:Case-Control Studies; D002766:Cholecystokinin / Q000097:blood; D002784:Cholesterol; D005260:Female; D042882:Gallstones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D002766:Cholecystokinin; D002784:Cholesterol; D043423:Carboxypeptidase H