title: The biology of circulating microRNAs in cardiovascular disease.
abstract: BACKGROUND
  Since their first description in mammalian cells, more than 2500 microRNA molecules have been predicted or verified within human cells. Recently, extracellular microRNAs have been described, protected from degradation by specialized packaging in extracellular vesicles or RNA-binding proteins.
  
  
  METHODS
  We will discuss recent data regarding circulating microRNAs, their potential role as novel biomarkers and intercellular communicators, as well as future challenges of studying and applying such novel biology, particularly in the cardiovascular system.
  
  
  RESULTS
  Circulating microRNAs have been proposed as attractive candidates as both diagnostic and prognostic biomarkers in various diseases, including a spectrum of cardiovascular conditions. Moreover, consistent with our evolving appreciation of the role of exosomes and microvesicles in intercellular communication, it has been proposed that delivery of active microRNAs to recipient tissues may serve as a primary mode of intercellular communication. Indeed, the transfer of functional microRNAs has been demonstrated in in vitro models and has been reported in a few in vivo contexts. In addition, therapeutic application of extracellular microRNAs has also been explored.
  
  
  CONCLUSIONS
  Over recent years, increasing attention has been paid to the role of circulating miRNAs in cardiovascular disease. As biomarkers and intercellular communicators, circulating miRNAs could play important roles in the prediction, diagnosis and tailored treatment of cardiovascular diseases in the near future.
authors.affiliation: Divisions of Cardiovascular and Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.|Cardiology Division, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Pil-Ki
authors.initials: PK
authors.lastname: Min
authors.affiliation: Divisions of Cardiovascular and Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Stephen Y
authors.initials: SY
authors.lastname: Chan
mesh_terms: D015415:Biomarkers; D002318:Cardiovascular Diseases / Q000235:genetics*; D002450:Cell Communication / Q000235:genetics; D055354:Exosomes / Q000378:metabolism; D000067128:Extracellular Vesicles / Q000378:metabolism; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*
chemical_list: D015415:Biomarkers; D035683:MicroRNAs
keywords: Argonaute 2; circulating microRNAs; disease biomarker; exosome; intercellular communication