Induction of PDGF-B in TCA-treated epidermal keratinocytes

Abstract

Trichloroacetic acid (TCA) is one of the most widely used peeling agents, and induces full necrosis of the whole epidermis, followed by reconstitution of the epidermis and the matrix of the papillary dermis. The cytotoxic effects of TCA, such as suppressing proliferation of keratinocytes and fibroblasts and protein synthesis by fibroblasts, have already been reported. However, the entire biological mechanism responsible for TCA peeling has yet to be determined. Hypothetical activation effects of TCA treatment on epidermal cells to induce production of growth factors and cytokines are examined, and are compared with its cytotoxic effects in terms of time course and applied TCA concentrations. After various periods of incubation with TCA, viability of Pam212 murine keratinocytes was investigated with MTT assay and dye exclusion assay, and production of growth factors and cytokines with reverse transcription-polymerase chain reaction (RT-PCR). Changes in platelet-derived growth factor (PDGF)-B mRNA expression and protein production in the human skin specimens after TCA application were then examined by RT-PCR and immunohistochemistry, respectively. Incubation with TCA showed cytotoxicity and induced death of Pam212 cells, depending on the incubation period and the TCA concentration. In addition, expressions of PDGF-B, tumor growth factor (TGF)-alpha, TGF- beta1 and vascular endothelial growth factor, which are the growth factors reportedly secreted from keratinocytes during wound healing, were all detected in Pam212 cells after short-term treatment with TCA. Expressions of inflammatory cytokines such as interleukin (IL)-1 and IL-10 were also induced. In TCA-treated NIH-3T3 fibroblasts, in contrast, observed was upregulation of only keratinocyte growth factor, which is reportedly secreted from fibroblasts, as well as the similar cytotoxic effect. In human skin, PDGF-B mRNA expression became significantly upregulated after TCA application, and then immediately downregulated. Immunoreactive PDGF-B in the cytoplasm of keratinocytes became detectable throughout the epidermis after TCA application, reached maximum after the peak of mRNA expression, and then declined significantly over 24 h when the epidermis became completely necrotic. The TCA-treated epidermis acts as a major source of growth factors, including PDGF-B, before undergoing full necrosis. This effect might contribute to a promotion of re-epithelialization and dermal regeneration without wound contraction and scarring.

Seborrhoeic keratosis removal in a multicentre phase I/II clinical trial using a novel topical formulation (BL-5010)

“…TCA, widely used as a peeling agent for the treatment of hyperkeratotic lesions, is known to induce coagulative necrosis of cells and eradication of solar elastosis, which is replaced by a thickened, homogenized band of dermal collagen and formation of normal epidermis . TCA treatment is also followed by the induction of various interleukins and growth factors, contributing to the healing and regeneration processes of the skin . Formic acid, used to remove tattoos and warts, to treat head lice and nits, and as a preservative in cosmetics, causes nonspecific protein cross‐linking and inhibition of mitochondrial function, leading to cell death, fixation and mummification of the tissues …”

Influence of chemical peeling on the skin stress response system

“…Previously, we showed that some specific growth factors including platelet-derived growth factor (PDGF)-B are transiently produced by TCA-treated Pam212 murine keratinocytes and human skin specimens after TCA application (25). The sources of PDGF in human dermal wound repair are keratinocytes, as well as platelets and monocytes.…”

Influence of trichloroacetic acid peeling on the skin stress response system

“…Culture of murine epidermal cell clone (Pam212) in the presence of TCA was described previously. 1 In brief, Pam212 was cultured in Dulbecco's modified Eagles medium (DMEM) supplemented with 5% fetal bovine serum and appropriate amounts of antibiotics and antimycotics (penicillin, streptomycin and amphotericin B) (Life Technologies, Carlsbad, CA, USA). The stock solution of TCA was prepared as a concentration of 5% (w ⁄ v) in DMEM and added at indicated concentrations to the cell culture showing approximately 70% confluency.…”

“…This fundamentally toxic reagent induces full necrosis of the whole epidermis, and the following reconstitution of the epidermis and the papillary dermis might have an important role in its rejuvenating effects. Previously, we have shown that some specific growth factors including platelet‐derived growth factor (PDGF)‐B, as well as various inflammatory cytokines, are transiently produced by TCA‐treated keratinocytes before their necrosis 1 . Induction of these growth factors and cytokines would be beneficial to better and faster wound healing.…”

“…Previously, we have shown that some specific growth factors including plateletderived growth factor (PDGF)-B, as well as various inflammatory cytokines, are transiently produced by TCA-treated keratinocytes before their necrosis. 1 Induction of these growth factors and cytokines would be beneficial to better and faster wound healing. However, the entire biological mechanisms involved in the TCA peeling have yet to be determined, especially those regulating inflammation.…”