First, when Smurf2 was overexpressed in the inner AF cells that express type II collagen during disc development, the cells started a senescence transition, reducing the ability to proliferate and synthesize matrix and leading to a decrease in cartilage matrix content at 2 months of age.23 Because matrix architecture in the inner AF was altered, moderate/severe clefts and tears occurred at 6 months of age.23 Second, the cells adjacent to the disrupted structure produced and released TGF‐β, which promoted CTGF production and secretion by local cells. This evidence concerns the gene CCN2 and atrial fibrillation.