The features of cardiomyopathy in AL and ATTR amyloidosis

Amyloidoses are protein misfolding diseases characterized by the accumulation of amyloid fibrils in the interstitium leading to the damage of an affected organ. Cardiac involvement is quite common and results from light chain amyloidosis (AL) or transthyretin amyloidosis (ATTR), including two subtypes: wild type (ATTRwt) and variant ATTR (ATTRv), which can lead to hereditary cardiac amyloidosis. Heart damage leads to life-threatening cardiomyopathy (CM) with poor prognosis. Besides the alteration of the tissue caused by the deposition of amyloid fibrils, experimental studies reveal some complex molecular mechanisms of the cytotoxic effects of amyloid. Although these effects are more prominent and defined in AL amyloidosis, they can also take place in ATTR and somehow affect the disease course. Analyzing the mechanisms on different levels is necessary for understanding of the development of the heart damage and prevention of progression of cardiac amyloidosis (CA). This study aims to conduct a comparative analysis of heart lesions and biochemical characteristics of AL and ATTR amyloidosis. This review was performed by searching the PubMed and Scopus databases for articles published until December 2023, using keywords such as “cardiomyopathy”, “AL amyloidosis”, “mass effect”, “cytotoxicity” and “ATTR amyloidosis”. Exclusion criteria included irrelevant articles and duplicates, with selected studies undergoing comprehensive review.