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: Hyejun Ra, Wibool Piyawattanametha, Emilio Gonzalez-Gonzalez, Michael J Mandella, Gordon S Kino, Olav Solgaard, Devin Leake, Roger L Kaspar, Anthony Oro, Christopher H Contag
• Journal: The Journal of investigative dermatology (J Invest Dermatol) Vol. 131 Issue 5 Pg. 1061-6 (May 2011) ISSN: 1523-1747 [Electronic] United States
• PMID: 21191407 (Publication Type: Evaluation Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Contrast Media
• RNA, Small Interfering
• Indocyanine Green

Topics

• Animals
• Contrast Media
• Humans
• Indocyanine Green
• Keratinocytes (pathology)
• Mice
• Microscopy, Confocal (instrumentation, methods)
• Microscopy, Fluorescence (instrumentation, methods)
• Pachyonychia Congenita (drug therapy, pathology)
• RNA, Small Interfering (therapeutic use)
• Skin (pathology)
• Skin Diseases (diagnosis, pathology)