title: Association between self-replicating calcifying nanoparticles and aortic stenosis: a possible link to valve calcification.
abstract: OBJECTIVE
  Among various hypotheses proposed for pathological tissue calcification, recent evidence supports the possibility that self-replicating calcifying nanoparticles (CNPs) can contribute to such calcification. These CNPs have been detected and isolated from calcified human tissues, including blood vessels and kidney stones, and are referred to as nanobacteria. We evaluated calcific aortic valves for the presence of CNP.
  
  
  RESULTS
  Calcific aortic valves were obtained from 75 patients undergoing surgical valve replacement. The control group was formed by eight aortic valves corresponding to patients with heart transplants. In the microbiology laboratory, valves were screened for CNP using a 4-6 weeks specific culture method. The culture for CNP was positive in 48 of the 75 valves with aortic stenosis (64.0%) in comparison with zero of eight (0%) for the control group (P = 0.0005). The observation of cultures by way of scanning electron microscopy highlighted the resemblance in size and morphology of CNP.
  
  
  CONCLUSIONS
  Self-replicating calcific nanometer-scale particles, similar to those described as CNP from other calcific human tissues, can be cultured and visualized from calcific human aortic valves. This finding raises the question as to whether CNP contribute to the pathogenesis of the disease or whether they are only innocent bystanders.
authors.affiliation: Servicio de Microbiología, Facultad de Medicina, Hospital Clínico Universitario, Valladolid, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Bratos-Pérez
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Sánchez
authors.forename: Susana
authors.initials: S
authors.lastname: García de Cruz
authors.forename: Eduardo
authors.initials: E
authors.lastname: Villacorta
authors.forename: Igor F
authors.initials: IF
authors.lastname: Palacios
authors.forename: José M
authors.initials: JM
authors.lastname: Fernández-Fernández
authors.forename: Salvatore
authors.initials: S
authors.lastname: Di Stefano
authors.forename: Antonio
authors.initials: A
authors.lastname: Orduña-Domingo
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Carrascal
authors.forename: Pedro
authors.initials: P
authors.lastname: Mota
authors.forename: Cándido
authors.initials: C
authors.lastname: Martín-Luengo
authors.forename: Javier
authors.initials: J
authors.lastname: Bermejo
authors.forename: José A
authors.initials: JA
authors.lastname: San Roman
authors.forename: Antonio
authors.initials: A
authors.lastname: Rodríguez-Torres
authors.forename: Francisco
authors.initials: F
authors.lastname: Fernández-Avilés
mesh_terms: D000368:Aged; D001024:Aortic Valve Stenosis / Q000382:microbiology* / Q000473:pathology; D001419:Bacteria / Q000302:isolation & purification*; D002114:Calcinosis / Q000382:microbiology* / Q000473:pathology; D016022:Case-Control Studies; D046508:Culture Techniques; D005260:Female; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D053758:Nanoparticles