Are cardiomyocytes able to generate pre-amyloid peptides?

We performed ultrastructural testing of a cardiac biopsy taken from a heart with amyloidosis in which transthyretin mutation and light chain A amyloidosis were excluded. Cardiomyocytes of the affected heart showed accumulation of endosomal-like structures in which soluble amyloid oligomeric conformation was deposited. Intracellular accumulation of β -amyloid as well as phosphorylated tau protein seen in the immunohistochemical study suggest that the heart tissue may generate an amyloidogenic peptide leading to cardiomyocyte destruction and heart dysfunction.