IL6 and cardiac hypertrophy: In addition, Datta et al. demonstrated that HSP90 increased the synthesis and secretion of exosomal IL-6, and that during hypertrophy, HSP90 is packaged with IL-6 in the exosomes for transfer to CFs, activating STAT-3 signaling pathway and excessive collagen synthesis, ultimately resulting in severely impaired cardiac function during cardiac hypertrophy [103].