Research progress and important scientific issues of organ fibrosis

Organ fibrosis is a common pathogenetic change of parenchymal organs under chronic conditions, characterized by increased fibrous connective tissues and reduced parenchymal cells. The essence of renal fibrosis is the "repair of scars" after renal tissue damage. It involves a loss of renal parenchyma cells, activation of myofibroblasts, deposition of extracellular matrix, imbalance of metabolism and abnormal interactions with organs. Hepatic fibrosis is a kind of repair response induced by various chronic hepatic diseases, including viral hepatitis and metabolic liver disease, and it is the common pathological basis of end-stage hepatic disease. Pulmonary fibrosis is a progressive and fatal inflammatory interstitial lung disease, characterized by inflammatory destruction and extracellular matrix deposition. Myocardial fibrosis is a process of pathological repair after a variety of injuries caused by hypertension, hypertrophic cardiomyopathy, viral cardiomyopathy, valve disorders, myocardial ischemia, diabetes, obesity and other metabolic abnormalities. Organ fibrosis indicates some common pathogenesis, but the exact mechanisms differ from organs and still need further investigation to identify biomarkers for early diagnosis and to devise drugs specifically for fibrosis. This article comprehensively summarizes the recent developments in organ fibrosis over the last 3 years, including underlying mechanisms and urgent scientific issues remained.