A narrative review on serum biomarkers of cardiac fibrosis

Myocardial fibrosis is the excessive deposition of extracellular matrix (ECM) proteins in the cardiac interstitium leading to pathological conditions of the heart. The objective is to understand the pathophysiology of cardiac fibrosis and the quest for serum biomarkers that will assist in early diagnosis before the occurrence of major cardiac events. There are many serum biomarkers that get elevated highlighting ECM remodeling during cardiac fibrosis. Lysyl oxidase like -2 is one such ECM protein, plays a crucial role in the up-regulation of TGF - β, the transformation of cardiac fibroblast to myoblast, the migration of collagen, and cross-linking of collagen and elastin. However, assessment of lysyl oxidase like-2 (LOXL-2) in different pathologically driven cardiac fibrosis is limited. Also, none of the serum biomarkers has proved to be the most accurate diagnostic tool for assessing fibrosis independently; hence, meticulous, less invasive, and cost-effective serum biomarkers need to be scrutinized. Hence lysyl oxidase Like-2 (LOXL-2) in combination with other serum biomarkers like PICP/PINP/TIMP-1/ST-2, or Galectin-3 can be combined to assess the presence of fibrosis in the heart. This review includes the journal, articles, and research paper on cardiac fibrosis which was published in the last 10–15 years to highlight the huge gap in the treatment of cardiac fibrosis and the need for a new combination of biomarkers with better prognostic and diagnostic value.