title: MicroRNA profiling of pericardial fluid samples from patients with heart failure.
abstract: OBJECTIVE
  Multicellular organisms maintain vital functions through intercellular communication. Release of extracellular vesicles that carry signals to even distant target organs is one way of accomplishing this communication. MicroRNAs can also be secreted from the cells in exosomes and act as paracrine signalling molecules. In addition, microRNAs have been implicated in the pathogenesis of a large number of diseases, including cardiovascular diseases, and are considered as promising candidate biomarkers due to their relative stability and easy quantification from clinical samples. Pericardial fluid contains hormones secreted by the heart and is known to reflect the cardiac function. In this study, we sought to investigate whether pericardial fluid contains microRNAs and if so, whether they could be used to distinguish between different cardiovascular pathologies and disease stages.
  
  
  RESULTS
  Pericardial fluid was collected from heart failure patients during open-heart surgery. MicroRNA profiles of altogether 51 patients were measured by quantitative real-time PCR (qPCR) using Exiqon human panels I and II. On the average, 256 microRNAs were detected per sample, and 70 microRNAs out of 742 profiled microRNAs were detected in every sample. The five most abundant microRNAs in pericardial fluid were miR-21-5p, miR-451a, miR-125b-5p, let-7b-5p and miR-16-5p. No specific signatures for cardiovascular pathologies or clinically assessed heart failure stages could be detected from the profiles and, overall, microRNA profiles of the samples were found to be very similar despite the heterogeneity in the study population.
  
  
  CONCLUSIONS
  Measured microRNA profiles did not separate the samples according to the clinical features of the patients. However, several previously identified heart failure marker microRNAs were detected. The pericardial fluid microRNA profile appeared to be a result of an active and selective secretory process indicating that microRNAs may act as paracrine signalling factors by mediating the local crosstalk between cardiac cells.
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Suvi M
authors.initials: SM
authors.lastname: Kuosmanen
authors.affiliation: School of Medicine, University of Eastern Finland, Kuopio, Finland; Heart Center, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Hartikainen
authors.affiliation: Heart Center, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Hippeläinen
authors.affiliation: School of Medicine, University of Eastern Finland, Kuopio, Finland; Anesthesia and Operative Services, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Hannu
authors.initials: H
authors.lastname: Kokki
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Anna-Liisa
authors.initials: AL
authors.lastname: Levonen
authors.affiliation: Department of Biotechnology and Molecular Medicine, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
authors.forename: Pasi
authors.initials: P
authors.lastname: Tavi
mesh_terms: D000368:Aged; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods*; D006333:Heart Failure / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D000069236:Pericardial Fluid / Q000378:metabolism; D019616:Thoracic Surgical Procedures
chemical_list: D035683:MicroRNAs