title: In vivo retinal and choroidal hypoxia imaging using a novel activatable hypoxia-selective near-infrared fluorescent probe.
abstract: OBJECTIVE
  Retinal hypoxia plays a crucial role in ocular neovascular diseases, such as diabetic retinopathy, retinopathy of prematurity, and retinal vascular occlusion. Fluorescein angiography is useful for identifying the hypoxia extent by detecting non-perfusion areas or neovascularization, but its ability to detect early stages of hypoxia is limited. Recently, in vivo fluorescent probes for detecting hypoxia have been developed; however, these have not been extensively applied in ophthalmology. We evaluated whether a novel donor-excited photo-induced electron transfer (d-PeT) system based on an activatable hypoxia-selective near-infrared fluorescent (NIRF) probe (GPU-327) responds to both mild and severe hypoxia in various ocular ischemic diseases animal models.
  
  
  METHODS
  The ocular fundus examination offers unique opportunities for direct observation of the retina through the transparent cornea and lens. After injection of GPU-327 in various ocular hypoxic diseases of mouse and rabbit models, NIRF imaging in the ocular fundus can be performed noninvasively and easily by using commercially available fundus cameras. To investigate the safety of GPU-327, electroretinograms were also recorded after GPU-327 and PBS injection.
  
  
  RESULTS
  Fluorescence of GPU-327 increased under mild hypoxic conditions in vitro. GPU-327 also yielded excellent signal-to-noise ratio without washing out in vivo experiments. By using near-infrared region, GPU-327 enables imaging of deeper ischemia, such as choroidal circulation. Additionally, from an electroretinogram, GPU-327 did not cause neurotoxicity.
  
  
  CONCLUSIONS
  GPU-327 identified hypoxic area both in vivo and in vitro.
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Shinichi
authors: S
authors: Fukuda
authors: Laboratory of Bioorganic & Natural Products Chemistry, Kobe Pharmaceutical University, Kobe, Japan.
authors: Kensuke
authors: K
authors: Okuda
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Genichiro
authors: G
authors: Kishino
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Sujin
authors: S
authors: Hoshi
authors: Laboratory of Pharmaceutical and Medicinal Chemistry, Gifu Pharmaceutical University, Gifu, Japan.
authors: Itsuki
authors: I
authors: Kawano
authors: Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
authors: Masahiro
authors: M
authors: Fukuda
authors: Laboratory of Regenerative Medicine and Stem Cell Biology, Graduate School of Comprehensive Human Science, University of Tsukuba, Ibaraki, Japan.
authors: Toshiharu
authors: T
authors: Yamashita
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors: Simone
authors: S
authors: Beheregaray
authors: Laboratory of Regenerative Medicine and Stem Cell Biology, Graduate School of Comprehensive Human Science, University of Tsukuba, Ibaraki, Japan.
authors: Masumi
authors: M
authors: Nagano
authors: Laboratory of Regenerative Medicine and Stem Cell Biology, Graduate School of Comprehensive Human Science, University of Tsukuba, Ibaraki, Japan.
authors: Osamu
authors: O
authors: Ohneda
authors: Laboratory of Pharmaceutical and Medicinal Chemistry, Gifu Pharmaceutical University, Gifu, Japan.
authors: Hideko
authors: H
authors: Nagasawa
authors: Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan. oshika@eye.ac.
authors: Tetsuro
authors: T
authors: Oshika
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002829:Choroid / Q000098:blood supply* / Q000473:pathology; D004195:Disease Models, Animal; D004596:Electroretinography; D004730:Endothelium, Vascular / Q000473:pathology*; D005451:Fluorescein Angiography; D005456:Fluorescent Dyes / Q000494:pharmacology; D005654:Fundus Oculi; D006801:Humans; D000860:Hypoxia / Q000150:complications* / Q000175:diagnosis; D051379:Mice; D008810:Mice, Inbred C57BL; D011817:Rabbits; D015203:Reproducibility of Results; D012164:Retinal Diseases / Q000175:diagnosis* / Q000209:etiology; D013050:Spectrometry, Fluorescence / Q000379:methods*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes
keywords: Hypoxia imaging; In vivo imaging; Near-infrared fluorescent probe; Ocular ischemia