Ultrastructural localization of integrin subunits alpha3 and alpha6 in capillarized sinusoids of the human cirrhotic liver

Integrin expression and function in the response of primary culture hepatic stellate cells to connective tissue growth factor (CCN2)

Production of connective tissue growth factor (CCN2, also known as CTGF) is a hallmark of hepatic fibrosis. This study examined early primary cultures of hepatic stellate cells (HSC) for (i) CCN2 regulation of its cognate receptor integrin subunits; and (ii) interactions between CCN2 and integrin α(5)β(1), heparan sulphate proteoglycans (HSPG) or fibronectin (FN) in supporting cell adhesion. HSC were isolated from healthy male Balb/c mice. mRNA levels of CCN2 or α(5), β(1), αv or β(3) integrin subunits were measured in days 1-7 primary culture HSC, and day 3 or day 7 cells treated with recombinant CCN2 or CCN2 small interfering RNA. Interactions between CCN2 and integrin α(5)β(1), HSPG or FN were investigated using an in vitro cell adhesion assay. Co-incident with autonomous activation over the first 7 days, primary culture HSC increasingly expressed mRNA for CCN2 or integrin subunits. Addition of exogenous CCN2 or knockdown of endogenous CCN2 differentially regulated integrin gene expression in day 3 versus day 7 cells. Either full length CCN2 ('CCN2(1-4)') or residues 247-349 containing module 4 alone ('CCN2(4)') supported day 3 cell adhesion in an integrin α(5)β(1) - and HSPG-dependent fashion. Adhesion of day 3 cells to FN was promoted in an integrin α(5) β(1)-dependent manner by CCN2(1-4) or CCN2(4), whereas FN promoted HSPG-dependent HSC adhesion to CCN2(1-4) or CCN2(4). These findings suggest CCN2 regulates integrin expression in primary culture HSC and supports HSC adhesion via its binding of cell surface integrin α(5)β(1), a novel CCN2 receptor in primary culture HSC which interacts co-operatively with HSPG or FN.

Circulating adhesion molecules in patients with virus-related chronic diseases of the liver

AIM: In the inflammatory state, intercellular adhesion molecule-1 (ICAM-1) and vascular cellular adhesion molecule-1 (VCAM-1) play a key role in promoting migration of immunological cells from the circulation to target site. Aim of our study was to investigate soluble forms of these molecules in patients with virus-related chronic liver diseases, to assess their behavior in different pathologies and correlation with severity of liver damage.

METHODS: Circulating ICAM-1 and VCAM-1 were assayed by EIA commercial kits (R&D System Co., Abington, UK) in 23 patients with chronic active hepatitis (CH), 50 subjects affected by liver cirrhosis (LC) and 15 healthy controls comparable for sex and age. In patients, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also detected by autoanalyzer.

RESULTS: LC patients had significantly higher ICAM-1 values than CH patients (38.567.4 ng/mL vs 20.896.42 ng/mL; P<0.001) and these ones had significantly higher values than controls (12.921.08 ng/mL; P<0.001). In CH group, ICAM-1 levels were significantly related to inflammatory activity (P = 0.041) and ALT values (r = 0.77; P<0.05). VCAM-1 values were significantly increased only in LC patients (P<0.001) and related to severity of liver impairment.

CONCLUSION: These findings suggest that the determination of serum ICAM-1 can be considered as an additional useful marker of hepatocellular necrosis and inflammatory activity in chronic hepatitis, while serum VCAM-1 is an indicator of liver fibrogenesis and severity of disease in cirrhosis.

Changes of ECM and CAM gene expression profile in the cirrhotic liver after HCV infection: Analysis by cDNA expression array

AIM: We aimed to observe the expression of extracellular matrix (ECM) and cellular adhesion molecules (CAM) in cirrhotic liver tissues after hepatitis C virus (HCV) infection.

METHODS: Twelve patients with post HCV inflammatory liver cirrhosis were selected to evaluate their liver function and other virological, pathological parameters. Then three specimens of cirrhotic patients whose health assessment results and laboratory data were similar and three normal liver specimens explanted from liver grafts prepared for liver transplantation were chosen for investigating gene expression of ECM and CAM using cDNA expression array.

RESULTS: The cDNA array assay revealed 36.7% (36/96) of genes with changes, in which 26.3% (26/96) was up-regulated and 10.1% (10/96) was down-regulated. Integrin (ITGA), collagen (COL), ADAMTS were identified as the characteristic changes of ECM and CAM gene expression levels. ITGA were demonstrated β1 and β2 sub-section changed in liver cirrhosis.

CONCLUSION: ECM and CAM play an important role in the progression of liver cirrhosis after HCV infection. The capital mechanism is related to the inflammatory cells infiltration, the activation and transformation of ECM producing cells and the imbalance between production and elimination of ECM.