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BACKGROUND@#Catheter-based pulmonary vein isolation (PVI) is an effective and well-established intervention for symptomatic paroxysmal atrial fibrillation (PAF). Nevertheless, late recurrences of atrial fibrillation (LRAF) occurring during 3 to 12 months are common, and the underlying mechanisms remain elusive. Circular RNAs (circRNAs) in atrial tissue have been linked to the pathophysiological mechanisms and progression of PAF in a few studies. However, their expression patterns in peripheral blood and regulatory function in LRAF are not clear.@*METHODS@#In the present study, the expression profile of circulating circRNAs in three paired nonvalvular PAF patients with or without LRAF was investigated by high-throughput sequencing and validated by quantitative real-time polymerase chain reaction (qRT-PCR). Bioinformatics analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and circRNA/miRNA regulatory network, were performed to predict the functions and potential regulatory roles of differentially expressed (DE) circRNAs.@*RESULTS@#A total of 12,834 circRNAs, comprising 5,491 down-regulated and 7,343 up-regulated circRNAs, were found to be DE in blood smaples from the two groups in peripheral blood between LRAF and non-recurrence control individuals. The most enriched GO categories in terms of molecular function, biological process, and cellular component features were catalytic activity, cellular metabolic process, and intracellular part, respectively. The KEGG enrichment study revealed that the most important metabolic process controlled by DE circRNAs is endocytosis. In the circRNA/microRNAs interaction network, four up-regulated circRNAs (hsa_circ_0002665, hsa_circ_0001953, hsa_circ_0003831, and hsa_circ_0040533) and one down-regulated circRNA (hsa_circ_0041103) were predicted to play potential regulatory roles in the pathogenesis of LRAF.@*CONCLUSIONS@#This investigation discovered the expression pattern of circulating circRNAs that is indicative of PAF late recurrence, which may serve as risk markers or therapeutic targets for LRAF after PVI.
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<p><b>OBJECTIVE</b>To explore the correlation of lymphocyte G protein-coupled receptor kinases 2 (GRK2) expression of the very elderly with chronic heart failure (HF) and heart ejection fraction (EF).</p><p><b>METHODS</b>16 elderly patients with chronic heart failure were divided into 2 groups as following: EF < 45% (n=7), EF > or = 45% (n=9); and health elderly as control (n=8). Lymphocytes were obtained from blood, reverse transcription polymerase chain reaction were used to measure GRK2 mRNA levels.</p><p><b>RESULTS</b>Lymphocyte GRK2 mRNA levels of EF < 45% group were higher than that of EF > 45% group, which were greater than that of control.</p><p><b>CONCLUSION</b>Elevation of lymphocyte GRK2 levels in HF is associated with heart EF, lymphocytes may provide a surrogate for monitoring cardiac GRK2 in human HF.</p>