Cytokines induce stress protein formation in cultured cardiac myocytes.

Diseases accompanied by severe cardiac impairment like sepsis and chronic uremia are frequently linked to an increase in cytokine release. In order to investigate possible toxic effects of the immune mediators on myocardial cells, we studied the contractility of cardiac myocytes and the de novo formation of stress proteins in cultured heart cells under cytokine exposition. All cytokines investigated induce, concentration-dependently, arrhythmias and cessation of spontaneous contractions. Interleukin(IL)-2, IL-3, IL-6, and tumor necrosis factor (TNF) stimulate the synthesis of a 30 kD stress protein in heart cells, whereas IL-1 additionally evokes two proteins of the 70 kD family. These findings confirm a direct interference of the interleukins and TNF with myocytes and, especially, myocardial protein formation. As the induction of stress proteins makes cells more resistant towards a subsequent challenge, the cytokines are possibly involved in the activation of cell protecting mechanisms in cardiac myocytes.