Red light is part of the visible light spectrum that does not generate DNA adducts associated with skin cancer and photoaging and may represent a safer therapeutic modality for treatment of keloid scars and other fibrotic skin diseases. Our laboratory previously demonstrated that light-emitting diode-generated red light (LED-RL) inhibits proliferation of skin fibroblasts. The effects of LED-RL on keloidal skin are not well characterized.
To determine the effect of LED-RL on keloid-derived fibroblast proliferation and viability in vitro.
Irradiation of primary keloid-derived human skin fibroblasts using LED-RL panels was performed in vitro, and modulation of proliferation and viability was quantified using trypan blue dye exclusion assay. Statistical analysis was performed using analysis of variance to compare treatment arms and the Student t-test to compare each treatment arm with the paired bench control arm.
Keloid fibroblasts treated with LED-RL 240, 320, and 480 J/cm demonstrated statistically significant dose-dependent decreases in relative proliferation rate of 12.4%, 16.5%, and 28.9%, respectively, compared with matched nonirradiated controls (p < .05) and did not significantly alter viability relative to the matched nonirradiated controls.
Light-emitting diode-generated red light can inhibit keloid fibroblast proliferation in a dose-dependent manner without altering viability. Light-emitting diode-generated red light has the potential to contribute to the treatment of keloids and other fibrotic skin diseases and is worthy of further translational and clinical investigation.
Scars and lasers.
[Article in French]
1Centre Laser de L'Arche Jacques Coeur, France. Rbousquetemail@example.com
Different lasers are used to improve scars in combination with other therapies. The pulsed dye laser is considered to be the gold standard for hypertrophic scars and keloids. Ablative laser treatments are used with atrophic scars. Ablative or non-ablative fractional laser treatments are developing rapidly due to the lower risk of infection and easier follow-up care.
Photomed Laser Surg. 2010 Aug;28 Suppl 1:S151-6. doi: 10.1089/pho.2008.2475.
Low–level laser irradiation (InGaAlP-660 nm) increases fibroblast cell proliferation and reduces cell death in a dose-dependent manner.
Frigo L1, Fávero GM, Lima HJ, Maria DA, Bjordal JM, Joensen J, Iversen VV, Marcos RL, Parizzoto NA, Lopes-Martins RA.
1Biological Sciences and Health Center, Cruzeiro do Sul University, São Paulo, Brazil. firstname.lastname@example.org
BACKGROUND AND OBJECTIVE:
Impaired cell metabolism and increased cell death in fibroblast cells are physiological features of chronic tendinopathy. Although several studies have shown that low–level laser therapy (LLLT) at certain parameters has a biostimulatory effect on fibroblast cells, it remains uncertain if LLLT effects depend on the physiological state.
STUDY DESIGN/MATERIAL AND METHODS:
High-metabolic immortal cell culture and primary human keloid fibroblast cell culture were used in this study. Trypan blue exclusion and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test were used to determine cell viability and proliferation. Propidium iodide stain was used for cell-cycle analysis by flow cytometry. Laser irradiation was performed daily on three consecutive days with a GaAlAs 660-nm laser (mean output: 50 mW, spot size 2 mm(2), power density =2.5 W/cm(2)) and a typical LLLT dose and a high LLLT dose (irradiation times: 60 or 420 s; fluences:150 or 1050 J/cm(2); energy delivered: 3 or 21 J).
Primary fibroblast cell culture from human keloids irradiated with 3 J showed significant proliferation by the trypan blue exclusion test (p < 0.05), whereas the 3T3 cell culture showed no difference using this method. Propidium iodide staining flow cytometry data showed a significant decrease in the percentage of cells being in proliferative phases of the cell cycle (S/g(2)/M) when irradiated with 21 J in both cell types (hypodiploid cells increased).
Our data support the hypothesis that the physiological state of the cells affects the LLLT results, and that high-metabolic rate and short- cell-cycle 3T3 cells are not responsive to LLLT. In conclusion, LLLT with a dose of 3 J reduced cell death significantly, but did not stimulate cell cycle. A LLLT dose of 21 J had negative effects on the cells, as it increased cell death and inhibited cell proliferation.
Photomed Laser Surg. 2010 Jun;28(3):417-22. doi: 10.1089/pho.2009.2548.
Effects of low–level laser therapy on pain and scar formation after inguinal herniation surgery: a randomized controlled single-blind study.
Carvalho RL1, Alcântara PS, Kamamoto F, Cressoni MD, Casarotto RA.
1Postgraduate Program in Rehabilitation Sciences, University of São Paulo, São Paulo, Brazil.
The aim of this study was to investigate the efficacy of an infrared GaAlAs laser operating with a wavelength of 830 nm in the postsurgical scarring process after inguinal-hernia surgery.
Low–level laser therapy (LLLT) has been shown to be beneficial in the tissue-repair process, as previously demonstrated in tissue culture and animal experiments. However, there is lack of studies on the effects of LLLT on postsurgical scarring of incisions in humans using an infrared 830-nm GaAlAs laser.
Twenty-eight patients who underwent surgery for inguinal hernias were randomly divided into an experimental group (G1) and a control group (G2). G1 received LLLT, with the first application performed 24 h after surgery and then on days 3, 5, and 7. The incisions were irradiated with an 830-nm diode laser operating with a continuous power output of 40 mW, a spot-size aperture of 0.08 cm(2) for 26 s, energy per point of 1.04 J, and an energy density of 13 J/cm(2). Ten points per scar were irradiated. Six months after surgery, both groups were reevaluated using the Vancouver Scar Scale (VSS), the Visual Analog Scale, and measurement of the scar thickness.
G1 showed significantly better results in the VSS totals (2.14 +/- 1.51) compared with G2 (4.85 +/- 1.87); in the thickness measurements (0.11 cm) compared with G2 (0.19 cm); and in the malleability (0.14) compared with G2 (1.07). The pain score was also around 50% higher in G2.
Infra-red LLLT (830 nm) applied after inguinal-hernia surgery was effective in preventing the formation of keloids. In addition, LLLT resulted in better scar appearance and quality 6 mo postsurgery.
Acta Cir Bras. 2011 Feb;26(1):25-30.
In vitro effect of 470 nm LED (Light Emitting Diode) in keloid fibroblasts.
Bonatti S1, Hochman B, Tucci-Viegas VM, Furtado F, Pinfildi CE, Pedro AC, Ferreira LM.
1Department of Surgery, UNIFESP, Sao Paulo, SP, Brazil.
To quantify keloid fibroblasts after irradiation with 470nm blue LED, in vitro.
Fibroblasts from keloid and adjacent skin have been obtained from 6 patients. Cells have been cultivated and maintained in DMEM culture medium. In Petri dishes, they were irradiated with energy doses of 6J, 12J and 18J. After 24 h, counting was done by the average of the triplicates for each sample.
There were no significant differences in the number of irradiated keloid fibroblasts at the studied doses (p=0.261). In adjacent skin fibroblasts, differences were observed (p=0.025) concerning the doses of 18 J and 6 J (p=0.03).
There was a reduction in the number of adjacent skin fibroblasts irradiated with 470nm blue LED at the energy dose of 18 J compared to the ones irradiated at the energy dose of 6 J. There were no changes in keloid fibroblasts counting at any of the doses applied, 24 h after irradiation.
Indian J Dermatol Venereol Leprol. 2005 Jan-Feb;71(1):31-4.
Efficacy of diode laser for treating acne keloidalis nuchae.
1The Skin and Laser Centre, Mumbai, Maharashtra, India. email@example.com
Acne keloidalis nuchae is usually treated with oral antibiotics, local antiseptics or intralesional steroids but with limited success. I assessed the efficacy of diode laser for treating the inflammatory and keloidal papules of acne keloidalis nuchae in two cases. The lesions in both the cases showed about 90 to 95% clearance after 4 treatment sessions at one to one and half month intervals. No new lesions were observed during the follow up period of six months after the last laser treatment. Thus, after clearing bacterial infection, laser hair epilation can be used as the first line of therapy for treating papules of acne keloidalis nuchae. This is the first attempt at treating acne keloidalis nuchae with a diode laser.