title: In vivo distribution of single chain variable fragment (scFv) against atherothrombotic oxidized LDL/β2-glycoprotein I complexes into atherosclerotic plaques of WHHL rabbits: Implication for clinical PET imaging.
abstract: BACKGROUND
  Oxidized LDL (oxLDL) can exist as a complex with β2-glycoprotein I (β2GPI) in plasma/serum of patients with non-autoimmune atherosclerotic disease or antiphospholipid syndrome (APS). Nonetheless, direct in vivo evidence supporting the pathophysiological involvement of oxLDL/β2GPI complexes and specific autoantibody against the complexes in developing atherothrombosis has yet been established. In the present study, we demonstrated in vivo distribution of single chain variable fragment of IgG anti-oxLDL/β2GPI complexes (3H3-scFv) in Watanabe heritable hyperlipidemic (WHHL) rabbits by PET/CT imaging.
  
  
  METHODS
  An antibody-based PET probe,64Cu-3H3-scFv, was established, and WHHL rabbits were applied for a non-autoimmune atherosclerotic model to demonstrate in vivo distribution of the probe.
  
  
  RESULTS
  3H3-scFv has exhibits specificity towards β2GPI complexed with oxLDL but neither a free form of β2GPI nor oxLDL alone. Post-intravenous administration of64Cu-3H3-scFv into WHHL rabbits has demonstrated a non-invasive approach for in vivo visualization of atherosclerotic lesion. The imaging probe achieved ideal blood clearance and distribution for optimal imaging capacity in 24h, significantly shorter than that of an intact IgG-based imaging probe.64Cu-3H3-scFv targeted on atherosclerotic plaques in aortas of WHHL rabbits where extensive accumulation of lipid deposits was observed by lipid staining and autoradiography. The accumulation of64Cu-3H3-scFv in aortic segments of WHHL rabbits was 2.8-folds higher than that of controls (p=0.0045).
  
  
  CONCLUSIONS
  The present in vivo evidence supports the pathophysiological involvement of oxLDL/β2GPI complexes in atherosclerotic complications of WHHL rabbits.64Cu-3H3-scFv represents a novel PET imaging probe for non-invasive pathophysiological assessment of oxLDL/β2GPI complexes accumulated in atherosclerotic plaques.
authors.affiliation: Collaborative Research Center for OMIC, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Collaborative Research Center for OMIC, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: IVD Development Department, Medical and Biological Laboratories Co, Ltd., Ina, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Kita
authors.affiliation: IVD Development Department, Medical and Biological Laboratories Co, Ltd., Ina, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kojima
authors.affiliation: SHI Accelerator Service Ltd., Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hirano
authors.affiliation: Collaborative Research Center for OMIC, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Lianhua
authors.initials: L
authors.lastname: Shen
authors.affiliation: Collaborative Research Center for OMIC, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Takenaka
authors.affiliation: Collaborative Research Center for OMIC, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan; Department of Urology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kumon
authors.affiliation: Collaborative Research Center for OMIC, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan; Department of Cell Chemistry, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan. Electronic address: eijimatu@md.okayama-u.ac.jp.
authors.forename: Eiji
authors.initials: E
authors.lastname: Matsuura
mesh_terms: D000818:Animals; D006801:Humans; D008077:Lipoproteins, LDL; D058226:Plaque, Atherosclerotic / Q000276:immunology*; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D011817:Rabbits; D057127:Single-Chain Antibodies / Q000276:immunology*; D053482:beta 2-Glycoprotein I / Q000276:immunology*
chemical_list: D008077:Lipoproteins, LDL; D057127:Single-Chain Antibodies; D053482:beta 2-Glycoprotein I; C099252:oxidized low density lipoprotein
keywords: Autoantibody; Oxidized LDL (oxLDL)/β(2)-glycoprotein I (β(2)GPI) complexes; PET/CT imaging; Watanabe heritable hyperlipidemic (WHHL) rabbit