DNA methylation stability in cardiac tissues kept at different temperatures and time intervals.

Investigating DNA methylation (DNAm) in cardiac tissues is vital for epigenetic research in cardiovascular diseases (CVDs). During cardiac surgery, biopsies may not be immediately stored due to a lack of human or technical resources at the collection site. Assessing DNAm stability in cardiac samples left in suboptimal conditions is crucial for applying DNAm analysis.

Fresh and frozen cardiac tissue are comparable in DNA methylation array β-values, but formalin-fixed, paraffin-embedded tissue may overestimate DNA methylation levels.

Untreated fresh cardiac tissue is the optimal tissue material for investigating DNA methylation patterns of cardiac biology and diseases. However, fresh tissue is difficult to obtain. Therefore, tissue stored as frozen or formalin-fixed, paraffin-embedded (FFPE) is widely used for DNA methylation studies.