We investigated a possible link between cardiac diseases and accompanying gene expression changes of key proteins in the Gq-coupled pathway such as PKCs, PLCs and InsP3R. For this we compared transcript levels of the respective genes in samples from control and diseased human hearts (auricles) using quantitative realtime PCR. To exclude that such changes depend on alterations of the tissue composition, we determined transcript levels of characteristic marker genes for particular cell types. Our results showed that in tissues from patients with atrial arrhythmias (without medication) the amount of fibronectin was significantly increased compared to tissue samples of arrhythmic atria with medications (beta-blocker, ACE inhibitors) and control tissues. Furthermore, the conventional PKC-isoform alpha that had formerly been linked to cardiac hypertrophy, displayed a significant correlation to fibronectin, vimentin (fibroblast) and endomucin (endothelia) with a lack of correlation to the cardiac myocyte markers troponin 1 and ryanidin receptor 2. This suggests, that observed changes in the atrial tissue might be related to alterations in the tissue composition rather than to changes in gene expression pattern of muscle cells.

This work was supported in part by the DFG (SFB 530) and the Saarland University science funding grants.