Intermediate filament and associated proteins in the human heart: an immunofluorescence study of normal and pathological hearts.

The cytoskeleton of human ventricular myocardium in normal and pathological hearts has been analysed with immunocytochemical techniques. Specific antibodies against the intermediate filament proteins desmin (Mr 55 000) and vimentin (Mr 58 000) and antibodies against two cytoskeleton-associated proteins, a spectrin-like protein (Mr 230 000) and vinculin (Mr 130 000), have been used. We show that desmin is localized in the myocytes as an intermyofibrillar lattice at the Z disk level of the myofibrils, and at the intercalated disks. The spectrin-like protein is localized as a transverse striated pattern interlinked with fine longitudinal strands in the subplasmalemmal region of the myocytes. Vinculin is abundant in the intercalated disks and in myotendinous junctions but occurs also at the peripheral sarcolemma in the form of a regular repeat of dots and of fine bar-like extensions into the cytoplasm from the dots. These patterns were observed both in normal and in abnormal hearts, but a number of altered patterns in pathological myocytes were also seen. It is concluded that the intermediate filament system has important implications in the structural function of normal and abnormal hearts but that further studies are needed to elucidate how the different components are related to each other and how they are influenced by different disease processes.