Chronic ethanol exposure induces cardiac fibroblast transdifferentiation via ceramide accumulation and oxidative stress

In vivo and vitro experiments revealed that chronic ethanol exposure induced increased myocardial fibrosis and augmented the transdifferentiation of myocardial fibroblasts. Simultaneously, it elicited an upregulation in the production of long-chain and very-long-chain ceramides in cardiac fibroblasts. The excessive accumulation of ceramide leads to elevated levels of intracellular oxidative stress, culminating in the activation of TGF-β-SMAD3 signaling and the development of fibrosis. Intervention of these pathways with pharmacological inhibitors in vitro or in vivo inhibited fibrosis. In conclusion, ethanol increased ceramides and reactive oxygen species (ROS) in cardiac fibroblasts, resulting in the activation of TGF-β-SMAD3 signaling, transdifferentiation of fibroblasts, and myocardial fibrosis.