title: Targeting angiogenesis using a C-type atrial natriuretic factor-conjugated nanoprobe and PET.
abstract: Sensitive, specific, and noninvasive detection of angiogenesis would be helpful in discovering new strategies for the treatment of cardiovascular diseases. Recently, we reported the (64)Cu-labeled C-type atrial natriuretic factor (CANF) fragment for detecting the upregulation of natriuretic peptide clearance receptor (NPR-C) with PET on atherosclerosis-like lesions in an animal model. However, it is unknown whether NPR-C is present and overexpressed during angiogenesis. The goal of this study was to develop a novel CANF-integrated nanoprobe to prove the presence of NPR-C and offer sensitive detection with PET during development of angiogenesis in mouse hind limb.
  
  
  METHODS
  We prepared a multifunctional, core-shell nanoparticle consisting of DOTA chelators attached to a poly(methyl methacrylate) core and CANF-targeting moieties attached to poly(ethylene glycol) chain ends in the shell of the nanoparticle. Labeling of this nanoparticle with (64)Cu yielded a high-specific-activity nanoprobe for PET imaging NPR-C receptor in a mouse model of hind limb ischemia-induced angiogenesis. Histology and immunohistochemistry were performed to assess angiogenesis development and NPR-C localization.
  
  
  RESULTS
  (15)O-H(2)O imaging showed blood flow restoration in the previously ischemic hind limb, consistent with the development of angiogenesis. The targeted DOTA-CANF-comb nanoprobe showed optimized pharmacokinetics and biodistribution. PET imaging demonstrated significantly higher tracer accumulation for the targeted DOTA-CANF-comb nanoprobe than for either the CANF peptide tracer or the nontargeted control nanoprobe (P < 0.05, both). Immunohistochemistry confirmed NPR-C upregulation in the angiogenic lesion with colocalization in both endothelial and smooth muscle cells. PET and immunohistochemistry competitive receptor blocking verified the specificity of the targeted nanoprobe to NPR-C receptor.
  
  
  CONCLUSIONS
  As evidence of its translational potential, this customized DOTA-CANF-comb nanoprobe demonstrated superiority over the CANF peptide alone for imaging NPR-C receptor in angiogenesis.
authors: Department of Radiology, Washington University, St Louis, Missouri 63110, USA.
authors: Yongjian
authors: Y
authors: Liu
authors: Eric D
authors: ED
authors: Pressly
authors: Dana R
authors: DR
authors: Abendschein
authors: Craig J
authors: CJ
authors: Hawker
authors: Geoffrey E
authors: GE
authors: Woodard
authors: Pamela K
authors: PK
authors: Woodard
authors: Michael J
authors: MJ
authors: Welch
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000737:chemistry / Q000378:metabolism* / Q000493:pharmacokinetics; D001667:Binding, Competitive; D001775:Blood Circulation; D008297:Male; D051379:Mice; D064847:Multimodal Imaging; D058726:Nanoconjugates; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D017461:Receptors, Atrial Natriuretic Factor / Q000378:metabolism; D014057:Tomography, X-Ray Computed; D015854:Up-Regulation; D014867:Water
chemical_list: D058726:Nanoconjugates; D010104:Oxygen Radioisotopes; D014867:Water; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor