In Vivo Imaging of Human and Mouse Skin with a Handheld Dual-Axis Confocal Fluorescence Microscope

James H Clark Center for Biomedical Engineering & Sciences, Department of Pediatrics, Stanford University, Stanford, California 94305, USA.
Journal of Investigative Dermatology (Impact Factor: 7.22). 12/2010; 131(5):1061-6. DOI: 10.1038/jid.2010.401
Source: PubMed


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.

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Available from: Emilio Gonzalez-Gonzalez, Jul 31, 2014
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    • "gene expression observed in other skin systems using intradermal injection, topical administration, or microneedle arrays (Gonzalez-Gonzalez et al., 2009, 2010b; Hsu and Mitragotri, 2011). The reason that more inhibition is not achieved is not clear, but similar results have been observed in nonskin tissues including eye (Huang et al., 2011), brain (Kuwahara et al., 2011), and heart (Guido et al., 2011), while higher levels of inhibition (up to 95%) have been reported in liver (Zimmermann et al., 2006; Frank-Kamenetsky et al., 2008; Tadin-Strapps et al., 2011). Although incomplete inhibition of gene expression was observed after treatment with sd-CD44 siRNA, complete silencing of a gene target may not be necessary to achieve a therapeutic effect. "
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