title: In vivo imaging of human and mouse skin with a handheld dual-axis confocal fluorescence microscope.
abstract: Advancing molecular therapies for the treatment of skin diseases will require the development of new tools that can reveal spatiotemporal changes in the microanatomy of the skin and associate these changes with the presence of the therapeutic agent. For this purpose, we evaluated a handheld dual-axis confocal (DAC) microscope that is capable of in vivo fluorescence imaging of skin, using both mouse models and human skin. Individual keratinocytes in the epidermis were observed in three-dimensional image stacks after topical administration of near-infrared (NIR) dyes as contrast agents. This suggested that the DAC microscope may have utility in assessing the clinical effects of a small interfering RNA (siRNA)-based therapeutic (TD101) that targets the causative mutation in pachyonychia congenita (PC) patients. The data indicated that (1) formulated indocyanine green (ICG) readily penetrated hyperkeratotic PC skin and normal callused regions compared with nonaffected areas, and (2) TD101-treated PC skin revealed changes in tissue morphology, consistent with reversion to nonaffected skin compared with vehicle-treated skin. In addition, siRNA was conjugated to NIR dye and shown to penetrate through the stratum corneum barrier when topically applied to mouse skin. These results suggest that in vivo confocal microscopy may provide an informative clinical end point to evaluate the efficacy of experimental molecular therapeutics.
authors.affiliation: James H. Clark Center for Biomedical Engineering & Sciences, Department of Pediatrics and the Molecular Imaging Program, Stanford University, Stanford, California, USA.|Edward L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
authors.forename: Hyejun
authors.initials: H
authors.lastname: Ra
authors.affiliation: James H. Clark Center for Biomedical Engineering & Sciences, Department of Pediatrics and the Molecular Imaging Program, Stanford University, Stanford, California, USA.|National Electronics and Computer Technology Center, Pathumthani, Thailand.|Advanced Imaging Research Center, Faculty of Medicine, Chulalongkorn University, Pathumwan, Thailand.
authors.forename: Wibool
authors.initials: W
authors.lastname: Piyawattanametha
authors.affiliation: James H. Clark Center for Biomedical Engineering & Sciences, Department of Pediatrics and the Molecular Imaging Program, Stanford University, Stanford, California, USA.
authors.forename: Emilio
authors.initials: E
authors.lastname: Gonzalez-Gonzalez
authors.affiliation: James H. Clark Center for Biomedical Engineering & Sciences, Department of Pediatrics and the Molecular Imaging Program, Stanford University, Stanford, California, USA.|Edward L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mandella
authors.affiliation: Edward L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
authors.forename: Gordon S
authors.initials: GS
authors.lastname: Kino
authors.affiliation: Edward L. Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
authors.forename: Olav
authors.initials: O
authors.lastname: Solgaard
authors.affiliation: Dharmacon Products, Thermo Fisher Scientific, Lafayette, Colorado, USA.
authors.forename: Devin
authors.initials: D
authors.lastname: Leake
authors.affiliation: James H. Clark Center for Biomedical Engineering & Sciences, Department of Pediatrics and the Molecular Imaging Program, Stanford University, Stanford, California, USA.|TransDerm, Santa Cruz, California, USA.
authors.forename: Roger L
authors.initials: RL
authors.lastname: Kaspar
authors.affiliation: Department of Dermatology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Oro
authors.affiliation: James H. Clark Center for Biomedical Engineering & Sciences, Department of Pediatrics and the Molecular Imaging Program, Stanford University, Stanford, California, USA.|Departments of Radiology and Microbiology & Immunology, Stanford University, Stanford, California, USA.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Contag
mesh_terms: D000818:Animals; D003287:Contrast Media; D006801:Humans; D007208:Indocyanine Green; D015603:Keratinocytes / Q000473:pathology; D051379:Mice; D018613:Microscopy, Confocal / Q000295:instrumentation / Q000379:methods; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods; D053549:Pachyonychia Congenita / Q000188:drug therapy / Q000473:pathology; D034741:RNA, Small Interfering / Q000627:therapeutic use; D012867:Skin / Q000473:pathology; D012871:Skin Diseases / Q000175:diagnosis* / Q000473:pathology
chemical_list: D003287:Contrast Media; D034741:RNA, Small Interfering; D007208:Indocyanine Green