No variation in Hsp70 mRNA level during cardiac surgery in pediatric patients evaluated by semiquantitative RT-PCR

We evaluated mRNA expression of the heat shock protein gene, Hsp70-1, by means of a semiquantitative RT-PCR in atrial tissue specimens from pediatric patients collected before and after cardiopulmonary bypass surgery for congenital heart diseases, to see whether surgical stress may affect the expression level of this mRNA. We studied thirty nine pediatric patients (aged 3 months to 15 years) undergoing surgical correction of congenital heart malformation. Twenty-one patients were affected by the tetralogy of Fallot, two by combined atrioventricular septal defects, six by ventricular septal defect, three by atrial septal defect, two by atrioventricular canal defect, two by pulmonary valve stenosis, one by mitral insufficiency, and one by double-outlet right ventricle. Our results showed no significant changes in the Hsp70-1 mRNA expression in atrial tissue of patients before and after cross-clamping (the mean relative expression after cross-clamping was 1.0+/-0.6 compared to the baseline value). Furthermore, no significant correlations were observed between cross-clamping time and temperature, cardiopulmonary bypass time and mRNA variation. Our study suggests that, during cardioplegia, myocardial tissue does not have an appropriate adaptive response to surgical stress.