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Immunohistochemical localization of transforming growth factor β-1 and its relationship with collagen expression in advanced liver fibrosis due to biliary atresia.

Farrington C, Novak D, Liu C, Haafiz AB - Clin Exp Gastroenterol (2010)

Bottom Line: The intensities of portal and lobular TGFβ1 expressions were compared.The results obtained by coimmunofluorescence staining showed no colocalization of α-SMA and TGFβ1.These findings suggest a paracrine mechanisms of TGFβ1-driven fibrogenesis in advanced BA.

View Article: PubMed Central - PubMed

Affiliation: Hepatology and Liver Transplantation, Division of Pediatric Gastroenterology, Hepatology and Nutrition.

ABSTRACT

Purpose: Biliary atresia (BA) is the most common indication of liver transplantation in children. Pathogenesis of hepatic fibrosis, which is a prominent feature of BA, remains obscure. The purpose of this work was to determine the cellular sources of transforming growth factor beta-1 (TGFβ1) and establish the relationship between TGFβ1-producing cells and extracellular matrix producing myofibroblasts (MFBs) in advanced BA.

Methods: Trichrome staining and immunohistochemistry were carried out to determine the expression pattern of collagen and TGFβ1 protein in explant liver specimens from patients with BA. The intensities of portal and lobular TGFβ1 expressions were compared. Immunofluorescence technique was carried out to determine the relationship between α-smooth muscle actin (α-SMA)-positive-MFB and TGFβ1-positve cells.

Results: Lobular TGFβ1 protein expression was significantly higher than portal (89 ± 6 versus 10 ± 1 arbitrary units, P ≤ 0.05), whereas no difference was noted in livers used as control (10 ± 1.6 versus 19 ± 5 arbitrary units, P = 0.11). TGFβ1 expression was more in the center of nodules versus MFB in surrounding fibrous septa. Contrary to TGFβ1 expression, α1-SMA was mostly expressed in the portal structures and the adjacent fibrous septa enacting lobulation of the parenchyma. The results obtained by coimmunofluorescence staining showed no colocalization of α-SMA and TGFβ1.

Conclusions: TGFβ1 protein expression is mostly localized to hepatocytes in advanced BA. These findings suggest a paracrine mechanisms of TGFβ1-driven fibrogenesis in advanced BA.

No MeSH data available.


Related in: MedlinePlus

Trichrome staining for collagen in human biliary atresia. Trichrome staining was done as described in the Materials and methods section. A) Thick bands of collagen septa (green) separating nodular liver tissue. B) Trichrome staining of a healthy control liver (original magnification ×10).Abbreviation: BA, biliary atresia.
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f1-ceg-3-185: Trichrome staining for collagen in human biliary atresia. Trichrome staining was done as described in the Materials and methods section. A) Thick bands of collagen septa (green) separating nodular liver tissue. B) Trichrome staining of a healthy control liver (original magnification ×10).Abbreviation: BA, biliary atresia.

Mentions: The purpose of trichrome staining was two-fold: 1) to determine the distribution of collagen to serve as a reference for the distribution of TGFβ1 and 2) to determine the extent of fibrosis by the METAVIR scoring system. In this system, F0 represents no fibrosis; F1, portal fibrosis without septa; F2, portal fibrosis and few septa; F3, numerous septa extending to adjacent portal tracts or terminal hepatic venules; and F4, cirrhosis. The mean METAVIR score was 3.8 ± 0.8 (N = 30, minimum 3, maximum 4), consistent with advanced cirrhosis, a typical feature of end-stage liver disease due to BA. A representative trichrome-stained slide is shown in Figure 1A showing thick collagenous bands interspersed between nodular liver tissues, thus producing portal-to-portal bridging fibrosis, a histological pattern typical for biliary cirrhosis. In contrast, healthy control livers (Figure 1B) had only minimal collagen staining in portal areas, consistent with noted F0 METAVIR scores.


Immunohistochemical localization of transforming growth factor β-1 and its relationship with collagen expression in advanced liver fibrosis due to biliary atresia.

Farrington C, Novak D, Liu C, Haafiz AB - Clin Exp Gastroenterol (2010)

Trichrome staining for collagen in human biliary atresia. Trichrome staining was done as described in the Materials and methods section. A) Thick bands of collagen septa (green) separating nodular liver tissue. B) Trichrome staining of a healthy control liver (original magnification ×10).Abbreviation: BA, biliary atresia.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3108674&req=5

f1-ceg-3-185: Trichrome staining for collagen in human biliary atresia. Trichrome staining was done as described in the Materials and methods section. A) Thick bands of collagen septa (green) separating nodular liver tissue. B) Trichrome staining of a healthy control liver (original magnification ×10).Abbreviation: BA, biliary atresia.
Mentions: The purpose of trichrome staining was two-fold: 1) to determine the distribution of collagen to serve as a reference for the distribution of TGFβ1 and 2) to determine the extent of fibrosis by the METAVIR scoring system. In this system, F0 represents no fibrosis; F1, portal fibrosis without septa; F2, portal fibrosis and few septa; F3, numerous septa extending to adjacent portal tracts or terminal hepatic venules; and F4, cirrhosis. The mean METAVIR score was 3.8 ± 0.8 (N = 30, minimum 3, maximum 4), consistent with advanced cirrhosis, a typical feature of end-stage liver disease due to BA. A representative trichrome-stained slide is shown in Figure 1A showing thick collagenous bands interspersed between nodular liver tissues, thus producing portal-to-portal bridging fibrosis, a histological pattern typical for biliary cirrhosis. In contrast, healthy control livers (Figure 1B) had only minimal collagen staining in portal areas, consistent with noted F0 METAVIR scores.

Bottom Line: The intensities of portal and lobular TGFβ1 expressions were compared.The results obtained by coimmunofluorescence staining showed no colocalization of α-SMA and TGFβ1.These findings suggest a paracrine mechanisms of TGFβ1-driven fibrogenesis in advanced BA.

View Article: PubMed Central - PubMed

Affiliation: Hepatology and Liver Transplantation, Division of Pediatric Gastroenterology, Hepatology and Nutrition.

ABSTRACT

Purpose: Biliary atresia (BA) is the most common indication of liver transplantation in children. Pathogenesis of hepatic fibrosis, which is a prominent feature of BA, remains obscure. The purpose of this work was to determine the cellular sources of transforming growth factor beta-1 (TGFβ1) and establish the relationship between TGFβ1-producing cells and extracellular matrix producing myofibroblasts (MFBs) in advanced BA.

Methods: Trichrome staining and immunohistochemistry were carried out to determine the expression pattern of collagen and TGFβ1 protein in explant liver specimens from patients with BA. The intensities of portal and lobular TGFβ1 expressions were compared. Immunofluorescence technique was carried out to determine the relationship between α-smooth muscle actin (α-SMA)-positive-MFB and TGFβ1-positve cells.

Results: Lobular TGFβ1 protein expression was significantly higher than portal (89 ± 6 versus 10 ± 1 arbitrary units, P ≤ 0.05), whereas no difference was noted in livers used as control (10 ± 1.6 versus 19 ± 5 arbitrary units, P = 0.11). TGFβ1 expression was more in the center of nodules versus MFB in surrounding fibrous septa. Contrary to TGFβ1 expression, α1-SMA was mostly expressed in the portal structures and the adjacent fibrous septa enacting lobulation of the parenchyma. The results obtained by coimmunofluorescence staining showed no colocalization of α-SMA and TGFβ1.

Conclusions: TGFβ1 protein expression is mostly localized to hepatocytes in advanced BA. These findings suggest a paracrine mechanisms of TGFβ1-driven fibrogenesis in advanced BA.

No MeSH data available.


Related in: MedlinePlus