title: Detection of hydroxyapatite in calcified cardiovascular tissues.
abstract: OBJECTIVE
  The objective of this study is to develop a method for selective detection of the calcific (hydroxyapatite) component in human aortic smooth muscle cells in vitro and in calcified cardiovascular tissues ex vivo. This method uses a novel optical molecular imaging contrast dye, Cy-HABP-19, to target calcified cells and tissues.
  
  
  METHODS
  A peptide that mimics the binding affinity of osteocalcin was used to label hydroxyapatite in vitro and ex vivo. Morphological changes in vascular smooth muscle cells were evaluated at an early stage of the mineralization process induced by extrinsic stimuli, osteogenic factors and a magnetic suspension cell culture. Hydroxyapatite components were detected in monolayers of these cells in the presence of osteogenic factors and a magnetic suspension environment.
  
  
  RESULTS
  Atherosclerotic plaque contains multiple components including lipidic, fibrotic, thrombotic, and calcific materials. Using optical imaging and the Cy-HABP-19 molecular imaging probe, we demonstrated that hydroxyapatite components could be selectively distinguished from various calcium salts in human aortic smooth muscle cells in vitro and in calcified cardiovascular tissues, carotid endarterectomy samples and aortic valves, ex vivo.
  
  
  CONCLUSIONS
  Hydroxyapatite deposits in cardiovascular tissues were selectively detected in the early stage of the calcification process using our Cy-HABP-19 probe. This new probe makes it possible to study the earliest events associated with vascular hydroxyapatite deposition at the cellular and molecular levels. This target-selective molecular imaging probe approach holds high potential for revealing early pathophysiological changes, leading to progression, regression, or stabilization of cardiovascular diseases.
authors.affiliation: Department of Radiology, The Methodist Hospital Research Institute, Weill Medical College of Cornell University, 6565 Fannin Street, #B5-009, Houston, TX 77030, USA.
authors.forename: Jae Sam
authors.initials: JS
authors.lastname: Lee
authors.forename: Joel D
authors.initials: JD
authors.lastname: Morrisett
authors.forename: Ching-Hsuan
authors.initials: CH
authors.lastname: Tung
mesh_terms: D001011:Aorta / Q000378:metabolism / Q000473:pathology; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D050197:Atherosclerosis / Q000378:metabolism* / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D002232:Carbocyanines / Q000378:metabolism; D002339:Carotid Arteries / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D017886:Durapatite / Q000378:metabolism*; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007700:Kinetics; D060526:Magnetic Fields; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging / Q000379:methods; D015335:Molecular Probes / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000473:pathology; D009842:Oligopeptides / Q000378:metabolism; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis; D058226:Plaque, Atherosclerotic; D011485:Protein Binding; D013997:Time Factors; D061205:Vascular Calcification / Q000378:metabolism* / Q000473:pathology; D055114:X-Ray Microtomography
chemical_list: D015415:Biomarkers; C098793:CY5.5 cyanine dye; D002232:Carbocyanines; D005456:Fluorescent Dyes; D015335:Molecular Probes; D009842:Oligopeptides; D015675:Osteocalcin; D017886:Durapatite; D016650:Fluorescein-5-isothiocyanate