The Effect Of Ursodeoxycholic Acid On Acute Cellular Rejection After Rat Liver Transplantation And Its Clinical Efficacy In The Early Stage After Adult Liver Transplantation

This study was designed to investigate the influence of ursodeoxycholic acid (UDCA) on common complications early after liver transplantation as well as possible mechanisms involved, and divided into the two parts as follows:(Ⅰ) The part of animal experimentObjectives:To investigate the effect of UDCA on acute cellular rejection (ACR) after rat liver transplantation and its possible mechanisms.Methods:After successful establishment of the ACR model of rat liver transplantation with stable biliary extra-drainage, 20 transplant rats were randomized to the UDCA or placebo group. Bile samples of all the rats were daily collected from postoperative day 1 to 7, and samples of whole blood and liver tissue were also done on day 7. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB), direct bilirubin (DB), alkaline phosphatase (AKP) andγ-glutamyl-transpeptidase (GGT) were measured. Histopathological assessment of ACR grading was made according to the Banff criterion. The mRNA expressions of interleukin (IL)-2, 4, 6, 10, tumor necrosis factor (TNF)-αand interferon (IFN)-γin liver tissue were analyzed with real-time fluorescence quantative PCR, and the protein levels of those cytokines were determined by Western blot analysis. Liquid chromatography-electrospray ionization tandem mass spectrometry (LC–MS/MS) was used to measure the bile and serum levels of ursodeoxycholic acid (UDCA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), cholic acid (CA), lithocholic acid (LCA), both in their conjugated (tauro- or glycol-conjugates) and unconjugated types.Results:1. Within post-transplant 7 days, the mean daily bile flow similarly decreased day by day between the two groups, and reached the significant differences on the 4th and 5th day (P=0.044, 0.008). No significant differences were found between them on the other days.2. The cases of mild ACR were significantly more in the UDCA group than those in the control group (P=0.023), and the incidence of interlobular biliary destruction had the contrary trend between the two groups (P=0.004).3. Though serum AST level of the UDCA group was significantly lower than that of the control group on day 7 (P=0.001), serum DB level of the former was significantly higher (P=0.039). There were no significant differences of other biochemical parameters between the two groups.4. In liver tissues harvested on day 7, the mRNA expression of IL-2 was lower in the UDCA group than that in the control group with significant difference (P=0.038), while the production of IL-4 was significantly promoted in the former (P<0.001). No significant differences were found about other cytokines between the two groups.5. The mean concentrations of total bile acids (TBA) in bile were similar between the two groups on postoperative every day (P>0.05). Compared with the control group, the bile concentrations of UDCA in the UDCA group were significantly higher on post-transplant day 2 to 4 (P<0.001, =0.016, <0.001), and UDCA proportions were also higher on day 2, 4 and 6 (P=0.009, 0.001, 0.043). Accordingly, the bile proportions of CA in the UDCA group were significantly lower than those in the control group on day 2, 4 and 7 (P<0.001, =0.005, 0.038), but on significant differences of the proportions of CDCA, DCA and LCA were found between the two groups.6. On the post-transplant 7th day, the serum concentrations of TBA, UDCA, CA, CDCA, DCA and LCA were similar between the two groups. However, the serum UDCA proportion of the UDCA group were higher than that of the control group (P=0.012), while the CA proportion was significantly lower than that of the latter (P=0.009). No significant differences of the other bile acids were found between the two groups. The serum concentrations of GUDCA and TUDCA in the UDCA group were significantly higher than those in the control group (P=0.014, 0.004). Among them, TUDCA proportion in the UDCA group were much lower (P=0.002), while unconjugated UDCA proportion in the former were higher than that in the latter (P<0.001).Conclusions:UDCA can turn down the severity of ACR after rat liver transplantation by decreasing histological ACR grading and the incidence of interlobular biliary destruction. Inhibition of the mRNA expression of IL-2 as well as promotion of IL-4 production in liver tissue might be the mechanism involved in its effect on ACR. Though UDCA treatment could not improve the ACR-induced cholestasis on the post-transplant 7th day, the proportion of non-toxic hydrophilic bile acid was apparently promoted without increase of TBA concentrations in either bile or serum.(Ⅱ) The part of clinical trialObjectives:To evaluate the efficacy of UDCA on graft function and common complications such as ischemia-reperfusion injury (IRI), ACR and drug-induced hepatotoxicity in the early stage after adult liver transplantation.Methods:Eighty liver transplant adult recipients were enrolled in our center and preoperatively randomized into the UDCA (42 cases) or control (38 cases) group between May, 2005 and June, 2006. The two groups were statistically compared in liver biochemical parameters on post-transplant day 1, 7, 14, 21, 28, rates of severe IRI-induced liver graft dysfunction, ACR episode, drug-induced hepatotoxicity, viral hepatitis and recurrence of primary liver disease as well as rates of vascular, biliary complications, infection and death within 1 and 3 months posttransplantation.Results:In the UDCA group, serum ALT levels on post-transplant day 7, 14, 21 were significantly lower than those in the control group(P=0.002, 0.030, 0.049). Compared with the control group, serum levels of AST and GGT were also lower in the UDCA group on day 7(P=0.012, 0.025). The cases of severe IRI-induced liver graft dysfunction in the UDCA group were significantly fewer than those in the control group (P=0.048). There were no significant differences in rates of ACR episode, histological ACR grading, drug-induced hepatotoxicity, rates of vascular, biliary complications infection, or death within 1 and 3 months posttransplantation between the two groups. No cases of viral hepatitis or recurrence of primary liver disease were found in the study.Conclusions:UDCA treatment can significantly promote graft function recovery and had a beneficial effect on ischemia-reperfusion injury early after adult liver transplantation. However, UDCA seemed to exert no significant influence on ACR episode, drug-induced hepatotoxicity, vascular/biliary complications, infection or death within the post-transplant 3 months.