Keeping the clocks ticking as we age: changes in sinoatrial node gene expression and function in the ageing heart.

摘要

The function of the sinoatrial node (SAN; the natural pacemaker of the heart) declines with age, leading to a condition called sick sinus syndrome, which is associated with a variety of cardiac arrhythmias or conduction disturbances (Dobrzynski et al. 2007). Sick sinus syndrome accounts for more than 50% of pacemaker implantations in people over 60 years of age. The decline in SAN function with age may occur as a result of structural changes (collagen deposition), alterations in ion channels (expression and/or function may be perturbed) and impairments in cell-to-cell communication (altered gap junction function). In this issue of Experimental Physiology, Tellez et al. (2011) have quantitatively characterized the expression of 86 mRNA transcripts (including ion channels, transporters, connexins and receptors) in the SAN and atrial myocardium from young (3 months) and aged (25 months) rats. Their data illustrate the enormous complexity of the ageing process in the heart.