Background: In myocardium of patients with chronic atrial fibrillation (AF) the expression of the mitochondrial heat shock proteins HSP60 and HSP10 is increased. They are responsible for folding and translocation of proteins inside the mitochondria. Import of these proteins is accomplished by mortalin. The aim of our study was to investigate if the expression of the heat shock protein mortalin is also increased in patients with AF.
Methods: Right atrial samples from 18 patients undergoing elective cardiac surgery were excised and immediately frozen in liquid nitrogen: 8 patients had chronic AF (> or = 3 month) and 10 patients were in sinus rhythm (SR). Mortalin was determined by SDS-PAGE, Western blot and quantified by optical densitometry.
Results: In myocardial samples from patients with chronic AF we found a more than 2-fold increase in mortalin expression.
Conclusions: The increased expression of mortalin may represent an adaptive heat shock response to restore cellular homeostasis.