PMC

Correlation between the percentage of portal tracts that demonstrated positive staining for TGF-β protein within BDECs (TGF-β %PTI) and the percentage of portals tracts involved (%PTI) in the histological abnormalities associated with CFLD. TGF-β %PTI was significantly correlated with %PTI (r = 0.65, P < 0.03; n = 12).

Quantitation of TGF-β₁ mRNA expression in CFLD and correlation with the histological grade of hepatic fibrosis. TGF-β₁ mRNA expression was standardized to the expression of the housekeeping gene, β-actin, in each of the CFLD biopsies and controls. The expression of TGF-β₁ mRNA in each CFLD biopsy was then expressed as a -fold increase versus controls. TGF-β₁ mRNA expression was significantly correlated with the histological grade of fibrosis (r = 0.78, P < 0.005; n = 11).

Serial liver sections from a child with CFLD demonstrating that CK-19-positive BDECs are responsible for the increased expression of TGF-β protein in expanded portal tracts. Immunohistochemistry for TGF-β protein expression (brown) in BDECs within established bile ducts surrounded by areas of fibrosis (A) and hyperplastic bile ductules in expanded portal tracts and at the growing margin of the scar tissue formation (C). Immunohistochemistry for CK-19 expression (red) in serial liver sections of A and C, respectively, in BDECs within established bile ducts surrounded by areas of fibrosis (B) and hyperplastic bile ductules in expanded portal tracts and at the growing margin of the scar tissue formation (D). Original magnifications, ×200.

Sections of liver tissue from a child with CFLD demonstrating TGF-β₁ expression most prominently in BDECs and to a lesser degree by hepatocytes at the scar interface. Immunohistochemistry for TGF-β protein expression (brown) in BDECs (A), and along the fibrous edge of a regenerative nodule in hepatocytes (C) and BDECs (D). B: No significant expression of TGF-β protein was seen in control liver tissue. E: In situ hybridization for TGF-β₁ mRNA expression (blue) demonstrated in BDECs using the anti-sense probe. F: In situ hybridization control using the TGF-β₁ mRNA sense probe, confirming specificity seen in C. Original magnifications: ×400 (A, D); ×200 (B, C, E, F).

Serial sections of liver tissue from a child with CFLD and biliary fibrosis demonstrating activated HSCs as the cellular source of collagen production. A: Hematoxylin/van Gieson stain demonstrating a portal tract with bile duct proliferation and fibrosis (pink) extending into the parenchyma. B: Immunohistochemistry for SMA (brown) and in situ hybridization using the anti-sense probe for procollagen α₁(I) mRNA (blue) demonstrating activated HSCs around bile ducts and in the advancing edge of the fibrosis. C: Immunohistochemistry for SMA (brown) and in situ hybridization using the sense (control) probe for procollagen α₁(I) mRNA, confirming specificity of in situ hybridization seen in B. Activated HSCs (brown) are more clearly seen around bile ducts and in the advancing fibrosis. D: Co-localization of procollagen α₁(I) mRNA expression (blue) to SMA-positive-activated HSCs (brown), showing stellate-shaped morphology of HSCs. Original magnifications: ×200 (A–C); ×1000 (D).

Activated HSCs in the presence of periductal fibrosis (A and B) and in the absence of histological fibrosis (C and D). Serial sections of liver tissue from a child with CFLD demonstrating fibrogenic activity and fibrosis around a bile duct viewed at high power. A: Activated HSCs demonstrated by immunohistochemistry for SMA (brown) surrounding an expanded bile duct. Current fibrogenic activity is seen in an activated HSC demonstrated by co-localization of SMA (brown) and procollagen α₁(I) mRNA (blue) (asterisk). B: Hematoxylin/van Gieson staining of a serial section demonstrating collagen deposition (pink) co-localized to the area of activated HSCs surrounding the expanded bile duct. HSCs expressing procollagen α₁(I) mRNA in A is identified (asterisk). C: Increased expression of SMA was also observed in CFLD liver without histological evidence of fibrosis. Perisinusoidal-activated HSCs demonstrated by immunohistochemistry for SMA (brown). D: Serial section stained with hematoxylin/van Gieson graded zero for fibrosis. Original magnifications: ×1000 (A, B); ×100 (C, D).