The Effect of Superpulsed Carbon Dioxide Laser Energy on Keloid and Normal Dermal Fibroblast Secretion of Growth Factors: A Serum-Free Study

Abstract

An in vitro model was used to determine the effect of superpulsed CO2 laser energy on normal dermal and keloid-producing fibroblast proliferation and release of growth factors. Growth factors assayed included basic fibroblast growth factor (bFGF) and transforming growth factor beta1 (TGF-beta1). bFGF is mitogenic, inhibits collagen production, and stabilizes cellular phenotype. TGF-beta1 stimulates growth and collagen secretion and is thought to be integral to keloid formation. Growth in a serum-free medium allowed measurement of these growth factors without confounding variables. Keloid and normal dermal fibroblasts cell lines were established from facial skin samples using standard explant techniques. Samples consisted of three separate keloid and three separate normal dermal fibroblast cell lines. Cells were used at passage 4 to seed 24-well trays at a concentration of 6 x 10(4) cells per milliliter in serum-free medium. At 48 hours, 18.8 percent of each cell well was exposed to a fluence of 2.4, 4.7, and 7.3 J/cm2 using the superpulsed CO2 laser. Cell viability and counts were established at four time points: 0 (time of superpulsed CO2 laser treatment), 24, 72, and 120 hours. Supernatants were collected and assessed for bFGF and TGF-beta1 using a sandwich enzyme immunoassay. All cell lines demonstrated logarithmic growth through 120 hours (conclusion of experiment), with a statistically significant shorter population doubling time for keloid fibroblasts (p < 0.05). Use of the superpulsed CO2 laser shortened population doubling times relative to that of controls; the differences were statistically significant in keloid dermal fibroblasts when fluences of 2.4 and 4.7 J/cm2 were used (p < 0.05 and 0.01, respectively). bFGF was present in greater levels in normal dermal fibroblasts than in keloid dermal fibroblasts. Application of superpulsed CO2 demonstrated a trend toward increased bFGF secretion in both fibroblast types; the increase was significant in the keloid group at 4.7J/cm2. A consistent trend in suppression of TGF-beta1 was seen in both groups exposed to superpulsed CO2, with the maximal effect occurring at 4.7 J/cm2. Serum-free culture sustains logarithmic cell growth and allows growth factor measurement without confounding variables from serum-containing media. Superpulsed CO2 enhances fibroblast replication and seems to stimulate bFGF secretion and to inhibit TGF-beta1 secretion. Given the function of these growth factors, the application of superpulsed CO2 may support normalized wound healing. These findings may explain the beneficial effects of laser resurfacing on a cellular level and support the use of superpulsed CO2 in the management of keloid scar tissue.

Connective Tissue Remodeling Induced by Carbon Dioxide Laser Resurfacing of Photodamaged Human Skin

“…21,22 Transforming growth factor ␤1 is powerfully profibrotic, and the elevated levels of this cytokine in CO 2 lasertreated skin, peaking 2 days after treatment but remaining high for at least 28 days after resurfacing, act to support ongoing new collagen formation. The increased TGF-␤1 levels reported herein are in contrast to those noted by Nowak et al 23 in a previous study regarding levels of this cytokine after CO 2 laser treatment in an in vitro model that used keloidal and normal dermal fibroblast cell lines. 23 In that study, there was a trend toward suppression of TGF-␤ in both normal and keloidal fibroblast-derived cell lines after CO 2 laser exposure.…”

“…The increased TGF-␤1 levels reported herein are in contrast to those noted by Nowak et al 23 in a previous study regarding levels of this cytokine after CO 2 laser treatment in an in vitro model that used keloidal and normal dermal fibroblast cell lines. 23 In that study, there was a trend toward suppression of TGF-␤ in both normal and keloidal fibroblast-derived cell lines after CO 2 laser exposure. Whether this difference is due to the fact that the current study specifically examined photodamaged skin rather than normal and keloidal tissue or perhaps is based on inherent differences between our in vivo study design and the in vitro nature of the previous work is not clear.…”

Combined Effect of Hyberbaric Oxygen and N-Acetylcysteine on Fibroblast Proliferation

“…It functions to stimulate mitosis, promote cell survival, inhibit collagen production, stabilize cellular phenotype, and induce angiogenesis. 25,26 It has a tissue half-life of roughly 8 hours. 27 This experiment showed a slight decrease in overall measured bFGF expression in eyelid dermal fibroblasts during the 7-day course of study when treated with 2 atm of HBO or 2 atm of HBO and NAC.…”

An unusual karyotype in leiomyoma: Case report and literature review

“…22 Interestingly, previous studies found that expression of TGFB3 mRNA levels in leiomyomas was elevated compared to matched myometrium. 23,24 These data suggest that TGFB3 may be important in uterine leiomyoma growth; however, there have been conflicting views on its effects, as high concentrations of TFGB3 did not simulate significant smooth muscle cell proliferation. 23 …”