“Optimal timing for RNA isolation: Recommendations for placenta sample collection under clinical conditions”

In placenta research, tissue quality is essential for following laboratory investigations. In clinical settings with deliveries as an unpredictable factor, delayed sampling or incorrect storage until sampling is a common problem. Therefore, we set out to define time points for different storage conditions where good tissue quality is still achievable. RNA related parameters like 260/280-ratio, RNA integrity number (RIN) and gene expression were analyzed in 172 samples over a 24-h interval. We suggest a cut-off-point of 3-h after delivery of the placenta to ensure good tissue and RNA quality, especially when selecting genes with complex or low mRNA expression levels.