Novel model for evaluation of epidermal preservation and dermal collagen remodeling following photorejuvenation of human skin

Kao, Bunsho; Kelly, Kristen M.; Majaron, Boris; Nelson, J. Stuart

doi:10.1002/lsm.10114

Cited by 16 publications

(13 citation statements)

References 9 publications

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“…As we noted significant epidermal damage for continuous spurts longer than 80 millisecond, 1.85 seconds appears to be the maximum permissible time that the skin surface can be exposed to sub-zero temperatures without inducing cryo-injury. As described in the Introduction, we have previously demonstrated the usefulness of the RAFT model for evaluating wound healing response after irradiation with photorejuvenation devices [11]. This paper identifies an additional indication for this tissue culture model, evaluation of cryogen-induced effects.…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of cryogen spray cooling exposure on in vitro model human skin

et al. 2004

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Section: Discussionmentioning

confidence: 99%

“…In a previous study, we demonstrated the usefulness of an in vitro model of human skin (floating collagen gel: RAFT) to evaluate the wound healing response after irradiation with devices used for photorejuvenation [11]. The RAFT model mimics in vivo human skin in terms of structure, cellular activity, and function [12].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of cryogen spray cooling exposure on in vitro model human skin

et al. 2004

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“…In comparable studies, human subjects have been used; however, using humans provides two intrinsic difficulties: ͑1͒ in measuring gene expression on a single subject over time and ͑2͒ in stringent medical limits ͑ethical and practical͒ of harvesting tissue samples at multiple times for histological and biochemical analysis. 15,16 In light of these difficulties, animal models are used as a more viable model to study hsp70 expression and other laser-induced tissue effects. 5,17 The porcine model is the closest nonprimate equivalent to human skin and is the most widely used dermal wound repair model, but because of differences in tissue architecture and immune responses, even it does not accurately reflect human wound healing.…”

Section: Introductionmentioning

confidence: 99%

Assessing laser-tissue damage with bioluminescent imaging

et al. 2006

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Effective medical laser procedures are achieved by selecting laser parameters that minimize undesirable tissue damage. Traditionally, human subjects, animal models, and monolayer cell cultures have been used to study wound healing, tissue damage, and cellular effects of laser radiation. Each of these models has significant limitations, and consequently, a novel skin model is needed. To this end, a highly reproducible human skin model that enables noninvasive and longitudinal studies of gene expression was sought. In this study, we present an organotypic raft model (engineered skin) used in combination with bioluminescent imaging (BLI) techniques. The efficacy of the raft model was validated and characterized by investigating the role of heat shock protein 70 (hsp70) as a sensitive marker of thermal damage. The raft model consists of human cells incorporated into an extracellular matrix. The raft cultures were transfected with an adenovirus containing a murine hsp70 promoter driving transcription of luciferase. The model enables quantitative analysis of spatiotemporal expression of proteins using BLI. Thermal stress was induced on the raft cultures by means of a constant temperature water bath or with a carbon dioxide (CO2) laser (lambda=10.6 microm, 0.679 to 2.262 Wcm2, cw, unfocused Gaussian beam, omegaL=4.5 mm, 1 min exposure). The bioluminescence was monitored noninvasively with an IVIS 100 Bioluminescent Imaging System. BLI indicated that peak hsp70 expression occurs 4 to 12 h after exposure to thermal stress. A minimum irradiance of 0.679 Wcm2 activated the hsp70 response, and a higher irradiance of 2.262 Wcm2 was associated with a severe reduction in hsp70 response due to tissue ablation. Reverse transcription polymerase chain reaction demonstrated that hsp70 mRNA levels increased with prolonged heating exposures. Enzyme-linked immunosorbent protein assays confirmed that luciferase was an accurate surrogate for hsp70 intracellular protein levels. Hematoxylin and eosin stains verified the presence of the thermally denatured tissue regions. Immunohistochemical analyses confirmed that maximal hsp70 expression occurred at a depth of 150 microm. Bioluminescent microscopy was employed to corroborate these findings. These results indicate that quantitative BLI in engineered tissue equivalents provides a powerful model that enables sequential gene expression studies. Such a model can be used as a high throughput screening platform for laser-tissue interaction studies.

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“…Recently, the RAFT organotypic culture model 4,[9][10][11] has been developed to study wound healing. A RAFT is an artificial tissue model consisting of fibroblasts embedded in a collagen gel with or without keratinocytes seeded on the surface.…”

Section: Original Articlementioning

confidence: 99%

“…The RAFT cultures with keratinocytes resemble skin and simulate the extracellular matrix and native environment of fibroblasts. 9 This provides a more natural growth environment in which to investigate fibroblast activity. Figure 1 depicts the layers, cellular components, and extracellular matrix of a RAFT tissue construct.…”

Section: Original Articlementioning

confidence: 99%