Mechanisms of liver fibrosis and methods of its assessment Emil Błazik, Magdalena Durlik Medical Science Review - Hepatologia 2010; 10 25-29 aaICID: 911665
Article type: Review article
IC™ Value: 3.34
Abstract provided by Publisher
Liver diseases which lead to hepatic dysfunction due to fibrosis constitute a major problem of modern hepatology. Fibrosis can be precipitated by infections, autoimmune reactions, poisonous and radioactive substances. Regenerative pathways are initially activated, but unrelenting exposure to harmful stimuli modifies proper healing, results in over-accumulation of extra-cellular matrix (ECM), due to both, continuous excessive synthesis of ECM components and lowered activity of proteolytic enzymes – metaloproteinases (MMPs). Overall remodeling of the liver depends on activation of hepatic stellate cells and their differentiation into a-SMA fibroblasts. This process is controlled by many cytokines secreted by monocytes and fibroblasts per se. Once started, fibrosis becomes irreversible, it can only be followed up as to its further progression. Liver biopsy remains a gold standard in evaluation of fibrosis, however at cost of sporadic serious complications, such as bleeding, pain or death. Organ/biopsy specimen disproportion, focal nature of fibrosis, interpersonal variability of evaluation by pathologists may result in inconsistency of biopsy results. Several fibrosis scoring systems have been developed to standardize interpretation of biopsy. Nevertheless, biopsy complications compel the search for non-invasive markers of fibrosis. Currently available assessment indexes account for direct and indirect markers. However, the accuracy of indirect scoring systems is insufficient. Therefore, other proteins/peptides are being tested as candidate markers in diagnostic panels, i.e. N-terminal peptide of III -pro-collagen and collagen type IV, MMP2, tissue inhibitor of metaloproteinases 1. Visualization techniques as ultrasound or MRI elastometry are currently studied as alternative fibrosis evaluation tools, with some success.