Heat shock protein 70-1 gene expression in pediatric heart surgery using blood cardioplegia.

Background: In response to many stress stimuli, cardiomyocytes produce a common set of heat shock proteins (HSP). Up-regulation of HSP70-1 (the inducible isoform) is known to reduce the risk of myocardial cell damage during open-heart surgery and seems to be protective against ischemia. We assessed hsp70-1 gene expression during blood cardioplegic arrest in children undergoing surgical correction of congenital heart defects. Methods: In tissue samples taken from the right atrium of 59 pediatric patients, we examined hsp70-1 gene expression using a real-time quantitative reverse transcription PCR, with 18S rRNA as internal standard. Results: On average, hsp70-1 gene expression was higher than the baseline level by a factor of 1.44± 0.17 (mean±SEM). A significant relationship between hsp70-1 mRNA levels and aortic cross-clamp time was observed (R2=0.069, p=0.044). Conversely, no significant correlation was observed between hsp70-1 mRNA levels and temperature. Conclusions: These data suggest that blood cardioplegia can induce an increment in the expression of hsp70-1, confirming its protective role in ischemia/ reperfusion injury.