Biomarker research is emerging as a rising trend within hepatology. The need of this exploration includes the growing burden of global liver disease, lack of early presenting symptoms in the natural history of a disease that may take decades to become evident, the presence of an invasive reference test like liver biopsy to evaluate disease severity, and the inadequacy of robust tools to calculate the effectiveness of therapeutic interventions.

As defined by National Institute of Health, a biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. They can be further categorized into hierarchical systems based on their potential to evaluate natural history (type 0: prognosis), biological activity (type 1: response to therapy), and therapeutic efficacy (type 2: surrogate for clinical efficacy).

The variety of pathological injury occurring in liver disease includes steatosis, necroinflammation, apoptosis, and fibrosis that increases the pool of potential biomarkers. These biomarkers at baseline and/or changing over time have the potential to predict these adverse events directly, which in turn can improve prognosis and offers a meaningful evaluation of clinical efficacy.  In view of the limitations of biopsy, numerous studies showed that noninvasive biomarkers including serum analytes and transient elastography measured at baseline has the potential to predict liver-related outcomes between 5 and 8 years. 

Portal hypertension, one of the most severe complications of liver disease should be managed at the earliest and both existing and emerging therapeutic strategies in the context of established cirrhosis are targeted towards lowering portal hypertension. The gold standard for its evaluation is the non-invasive marker, hepatic venous pressure gradient (HVPG) and mounting evidence supports its prognostic value and effectiveness in directing management. 

Source: Aithal GP, Guha N, Fallowfield J, Castera L, Jackson AP. Biomarkers in liver disease: emerging methods and potential applications. Int J Hepatol. 2012;2012:437508.