1. ¹Graduate Institute of Clinical Medical Sciences, Chang Gung University, Lin-Ko, Taiwan
2. ²Department of Pathology, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
3. ³Department of Pediatric Surgery, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
4. ⁴Department of Surgery, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
5. ⁵Department of Education and Research, Veterans General Hospital, Kaohsiung, Taiwan

Correspondence: Dr J-H Chuang, MD, Department of Pediatric Surgery, Chang Gung Memorial Hospital, 123 Ta-Pei Road, Niao-Sung Hsiang, Kaohsiung County 833, Taiwan. E-mail: jhchuang@adm.cgmh.org.tw

Received 27 May 2004; Revised 8 December 2004; Accepted 8 December 2004; Published online 28 January 2005.

Abstract

Matrix metalloproteinases (MMPs) are the proteases responsible for tissue remodeling during liver fibrosis caused by various disorders including biliary atresia. However, information regarding the relative contribution of these proteases to liver fibrosis is still limited. We studied matrix metalloproteinase-2 (MMP-2), -7, -9 and -13 mRNA expressions in the liver tissue of early-stage biliary atresia at the time of Kasai's procedure, late-stage biliary atresia at the time of liver transplantation with advanced fibrosis and nondiseased control without liver fibrosis. The results of real-time quantitative reverse transcriptase-PCR analysis revealed that only MMP-2 and -7 expressions were significantly different between groups. MMP-2 was significantly higher in Liver Transplantation group than both in Control (P=0.010) and in Kasai's Procedure (P=0.001) groups, whereas the difference of MMP-2 expression between Control and Kasai's Procedure was not significant. However, the relative expression level of MMP-7 was sequentially elevated when comparing Control, Kasai's Procedure and Liver Transplantation groups, and there was significant (P=0.019) difference when comparing Control and Liver Transplantation groups. Moreover, the fold difference in MMP-7 mRNA was much higher than that in MMP-2 mRNA between groups. The expressions of MMP-7 were further confirmed by agarose gel electrophoresis and Western blotting. Immunohistochemical analysis revealed a significant positive correlation of the scores of MMP-7 immunostaining with the stages of liver fibrosis. In situ hybridization demonstrated that the bile ductular epithelial cells, Kupffer cells and hepatocytes were the major producers of matrix metalloproteinase-7 in the liver. Our results imply that MMP-7 is a major MMP associated with the tissue remodeling during the progression of liver fibrosis in biliary atresia.