Alterations in gene expression of proteins involved in the calcium handling in patients with atrial fibrillation

Gene Expression in Human Atrial Fibrillation, Introduction: Atrial fibrilla tion (AF) leads to a loss of atrial contraction within hours to days. Durin g persistence of AF, cellular dedifferentiation and hypertrophy occur, even tually resulting in degenerative changes and cell death, Abnormalities in t he calcium handling in response to tachycardia-induced intracellular calciu m overload play a pivotal role in these processes. Methods and Results: The purpose was to investigate the mRNA expression of proteins and ion channels influencing the calcium handling in patients with persistent AF, Right atrial appendages were obtained from 18 matched contr ols in sinus rhythm (group 1) and 18 patients with persistent AF undergoing elective cardiac surgery. Previous duration of AF was less than or equal t o 6 months in 9 (group 2) and > 6 months in 9 patients (group 3), In a sing le semiquantitative polymerase chain reaction, the mRNA of interest and of glyceraldehyde-3-phosphate dehydrogenase, were coamplified and separated by gel electrophoresis. L-type calcium channel alpha(1) subunit mRNA content was inversely related to the duration of AF: -26% in group 2 compared to gr oup 1 (P = 0.2), and -49% in group 3 compared to group 1 (P = 0.01), Inhibi tory guanine nucleotide binding protein i alpha(2) mRNA content was reduced in group 3 compared to group 1 (-30%, P = 0.01), Sarcoplasmic reticulum ca lcium ATPase, phospholamban and sodium-calcium exchanger mRNA contents were not affected by AF, Conclusions: AF-induced alterations in mRNA contents of proteins and ion ch annels involved in the calcium handling seem to occur in relation to the pr evious duration of AF, In the present patient population, these changes wer e significantly only if AF lasted > 6 months.