title: Cutaneous penetration of the topically applied photosensitizer Pc 4 as detected by intravital 2-photon laser scanning microscopy.
abstract: The fundamental mechanism of photodynamic therapy (PDT)-induced cell death has been characterized, but early critical PDT events in vivo remain incompletely defined. With the recent development in advanced fluorescence imaging modalities, such as intravital 2-photon laser scanning microscopy (2P-LSM), researchers are now able to investigate and visualize biological processes with high resolution in real time. This powerful imaging technology allows deep tissue visualization with single-cell resolution, thus providing dynamic information on the 3-dimensional architectural makeup of the tissue. The main goal of this study was to determine the cutaneous penetration of a topically applied photosensitizer, the silicon phthalocyanine Pc 4, into the skin of live animals and to assess the effective absorption of Pc 4 through the skin barrier. Our 2P-LSM images indicate that Pc 4 penetrates to the epidermal/dermal junction of mouse skin. The data also indicate that the degree of Pc 4 absorption is dose dependent. These findings represent initial steps that may help in improving the clinical utilization of topical Pc 4-PDT.
authors.affiliation: Division of Pediatric Hematology/Oncology, Department of Pediatrics, Case Western Reserve University/University Hospitals Case Medical Center, Cleveland, OH 44106, USA.
authors.forename: Alex Y
authors.initials: AY
authors.lastname: Huang
authors.forename: Jay T
authors.initials: JT
authors.lastname: Myers
authors.forename: Deborah
authors.initials: D
authors.lastname: Barkauskas
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Howell
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Oleinick
authors.forename: Thomas S
authors.initials: TS
authors.lastname: McCormick
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Cooper
authors.forename: Elma D
authors.initials: ED
authors.lastname: Baron
authors.forename: Minh
authors.initials: M
authors.lastname: Lam
mesh_terms: D000287:Administration, Topical; D000818:Animals; D005260:Female; D007211:Indoles / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal / Q000379:methods*; D036641:Microscopy, Fluorescence, Multiphoton / Q000295:instrumentation / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D012867:Skin / Q000166:cytology* / Q000378:metabolism*; D012869:Skin Absorption / Q000502:physiology*
chemical_list: D007211:Indoles; D017319:Photosensitizing Agents; C107448:phthalocyanine Pc 4