title: Identifying the Palisades of Vogt in Human Ex Vivo Tissue.
abstract: The Palisades of Vogt (POV) constitute the corneal epithelial stem cell niche, but identification of this region in ex vivo tissue is difficult. Here we introduce a simple, direct method of identifying the POV in unsectioned, ex vivo human tissue.
  
  
  
  Twenty-two eyes were studied, four whole and eighteen rims. Orientation of whole eyes was determined and the eyes were marked to maintain their cardinal orientation prior to dissection. Samples were imaged with brightfield, linearly polarized light and transmitted circularly polarized light (CPL), and optical coherence tomography (OCT) volumes were acquired in all twelve clock hrs around the limbus. Five samples were also fluorescently labeled to identify the epithelial basement membrane, and whole mounts were imaged with laser scanning confocal microscopy. Images were compared to confirm that the structures visible with polarized light were POV.
  
  
  
  Under CPL the POV presented as amber radial ridges visible in the superior and inferior regions of the tissue. Identification of POV was confirmed by correlating the structures seen under CPL, OCT and laser-scanning confocal microscopy.
  
  
  
  CPL can be used to quickly identify POV regions in donor tissue. This technique can assist in targeted harvesting of stem cell regions for research and tissue for limbal transplant.
authors: University of Pittsburgh School of Medicine, Department of Ophthalmology, Pittsburgh, Pennsylvania, USA; University of Pittsburgh Swanson School of Engineering, Department of Bioengineering, Pittsburgh, Pennsylvania, USA.
authors: Ian A
authors: IA
authors: Sigal
authors: University of Pittsburgh School of Medicine, Department of Ophthalmology, Pittsburgh, Pennsylvania, USA.
authors: Jessica
authors: J
authors: Steele
authors: University of Pittsburgh School of Medicine, Department of Ophthalmology, Pittsburgh, Pennsylvania, USA.
authors: Scott
authors: S
authors: Drexler
authors: University of Pittsburgh School of Medicine, Department of Ophthalmology, Pittsburgh, Pennsylvania, USA; University of Pittsburgh Swanson School of Engineering, Department of Bioengineering, Pittsburgh, Pennsylvania, USA. Electronic address: lathropkl@upmc.edu.
authors: Kira L
authors: KL
authors: Lathrop
mesh_terms: D000328:Adult; D000368:Aged; D019573:Epithelium, Corneal / Q000033:anatomy & histology* / Q000166:cytology; D006801:Humans; D016850:Limbus Corneae / Q000033:anatomy & histology* / Q000166:cytology; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008859:Microscopy, Polarization; D008875:Middle Aged; D013194:Staining and Labeling / Q000379:methods; D055153:Stem Cell Niche; D014019:Tissue Donors; D041623:Tomography, Optical Coherence
keywords: POV; cornea; corneal epithelium; corneal transplant; limbus; palisades of Vogt; polarized light; stem cell niche