RNA isolation from fetal and adult human tissues for transcriptional profiling.

Investigations involving rare human tissues that are difficult to acquire due to their scarcity are highly challenging. The need to verify microarray analysis data by additional methods such as immunohistochemical staining and quantitative PCR creates an even greater demand for these valuable tissues. Furthermore, since rare human tissues may come from different sources and may have been processed by variable methods, the comparability of these samples must be verified. The aim of this study was to determine and validate a processing method that allows the analysis of human fetal and adult cardiovascular tissues from different sources that were preserved using varying methods. Due to restricted access to fresh human tissues and the need to accumulate these samples over an extended period of time, we used formalin-fixed paraffin-embedded tissues for gene expression analyses. We analyzed RNA levels from four different age groups: fetal first and second trimester, adolescents, and adults. In this study, we present an improved standard processing procedure for tissue sample processing and analysis of rare human cardiovascular tissues.