Are there any genotoxic effects of laser epilation applications on human? An observational study.
Removal of unwanted hair from the body is an important concern for women of any age and even for men for cosmetic reasons. Increased hair development in some body areas also comprises an important cosmetic/psychosocial problem for some people. Light Amplification by the Stimulated Emission of Radiation (LASER) has largely replaced the traditional methods of hair removal because of the relatively permanent results obtained by this method when compared with the other methods. It was reported that, by this method which is based on the use of selective photothermolysis, the melanin pigment within the hair follicle is targeted without giving any damage to the surrounding tissue. M Conversion of laser to thermal energy at the hair follicle that absorbs laser causes thermal damage to the hair follicle. 
New applications that are implemented to our daily lives with the technological developments remind us the possibility of mutations in human beings that can be caused by the new application. For this reason, different in vitro, short term mutagenicity tests that can be used to investigate the potential mutagenic and carcinogenic effects of these new applications have been developed. Sister chromatid exchange (SCE) test is one of these. It is a sensitive and simple test as well as being safe and reliable.  SCE arises by reciprocal DNA interchanges between sister chromatids during replication of damaged DNA templates. Exposure to some chemical, viral or environmental hazards, ionizing radiation, ultraviolet light, psoralen+ultraviolet A (PUVA) therapy and malignancies can lead to certain levels of SCE.  In this study, we investigated whether laser hair removal has chromosomal side effects by using SCE analysis.
MATERIALS AND METHODS
This study was planned in a prospective manner. Forty healthy volunteer women that admitted to the dermatology clinics for the removal of unwanted hair by laser epilation were enrolled to the study. The patients were also followed in terms of the dermatologic complications that could occur as a result of the laser epilation procedure. Exclusion criteria were the presence of any chronic systemic disease like cardiovascular diseases, any malignancy, history of radiotherapy or chemotherapy, cigarette smoking or substance addiction, use of alcohol, current use of oral contraceptive pills, known hormonal disorders and history of laser hair removal or laser electrolysis. No topical anesthetics were used during the laser application. The laser session intervals were decided to be kept as at least 1 month. Alexandrite laser system (Light Age Epicare Duo) at 755 nm wavelength was used for the epilation procedure. Only patients that had laser epilation to the whole leg (lower leg + upper leg) and face were included. Skin types of all patients were classified according to the Fitzpatrick Scale.  The spot size, shooting time (millisecond) and energy (joules/[cm.sup.2]) were adjusted according to the Fitzpatrick skin type and the area of the skin in the body to which the procedure would be applied.
Analysis of Sister Chromatid Exchange
For SCE analysis, 1 mL of blood was drawn to heparinized tubes from each individual before and 24 hours after the 1st laser application. Cultures were established by adding 0.5 mL of blood to 5 mL karyotyping medium (Biological Industries, Beit Haemek, Israel) with 2% phytohaemagglutinin M (PHA) (Biological Industries, Beit Haemek, Israel), and incubating for 24 h at 37[degrees]C. A 5-bromo-2'-deoxyuridine (BrdU) (Sigma, St. Louis, MO, USA) solution was added to a final concentration of 5mg/mL. Lymphocytes were cultured in the dark for 48 h and metaphases were blocked during the last 2 h with colcemid (Biological Industries, Beit Haemek, Israel) at a final concentration of 0.1 g/mL. The preparations were stored at room temperature for 3 days. At the end of this duration, each preparation was stained with fluorescence-plus-Giemsa (FPG) technique. Fifty second-division metaphases were scored on coded slides by a single observer, and expressed as the number of SCEs/cell per subject. Staff performing the SCE analysis was blinded to the study. At least 20 metaphases/sample were investigated under microscope (Olympus BX50) at 100x amplification. In each chromosome, the dark stained areas where the SCE regions skip from one chromatid to the other were accepted as 1 change. By this way, mean SCE frequency of each case was evaluated.
All statistical analyses were performed using the SPSS software package 15.0 (SPSS Inc, Chicago, IL, USA). Data were presented as frequencies and percentages for categorical variables and mean [+ or -] SD or median for continuous variables, unless otherwise indicated. A Wilcoxon's Rank Test was performed for the assessment of any differences between the first and second values of the dependent groups. Correlation between continuous variables was determined by Pearson correlation coefficients. A p-value of < 0.05 was considered as statistically significant.
Forty voluntary women that had laser epilation to the whole leg (lower + upper) and face were included in the study. The mean age of the women was 24.9 [+ or -] 2.14. The SCE frequencies that were obtained prior to the laser epilation were compared to those obtained after the laser epilation and no statistically significant differences were observed (Table 1). According to the skin types, eight (20%) cases were evaluated as type II, 18 (45%) cases were evaluated as type III, 14 (35%) cases were evaluated as type IV using the Fitzpatrick scale. Short-term adverse effects, including erythema, pruritus, and folliculitis were seen in a few case. They generally occurred in subjects with darker skin types. There were no long-term permanent pigmentary changes.
Electromagnetic radiation (EMR) is the primary form of energy that includes photons and shows wave properties. It includes X rays, gamma rays, ultraviolet radiation, visible light, infrared radiation, microwave and radio waves, from shorter to longer wavelengths, respectively. Laser beams are reported to be in a spectrum between the visible light and infrared wavelength.  Because of the infrared energy it includes, it is reported that laser beam has a propensity to cause an increased temperature within the tissue which could result in thermal damage. 
There are many temporary or permanent side effects that are reported to occur due to laser epilation procedures. Most of these are the dermatologic side effects that occur as a result of increased temperature within the tissues and include pain, erythema, hyper- or hypopigmentation.  However, as far as we know, the relation of laser epilation with genotoxicity has not been studied before. Previously, it was known that visible light would have no effect on DNA since it is not absorbed by DNA. But in a recent study, Kamil et al. reported that visible light on its own, without an additional exogenous light source could lead to local sublethal DNA damage.  But, the study conditions and methods in this study were different from ours and they used HeLa cells instead of the lymphocytes. Absence of chromophores in lymphocytes and the different methods that we used may be the cause of the different results that we obtained in our study.
In a similar study performed by Kong et al. by using phase contrast microscope, it was found that some of the high power and pulsed lasers could lead to nuclear damage and some morphologic changes.  But the parameter evaluated in this study was the nuclear damage instead of the change in SCE frequencies. Also the laser system they used was also different and at a different wavelength from the system that we used (Alexandrite).
The mutagenic and carcinogenic effects of the phototherapy lamps which emits short wavelength visible light similar to laser have been demonstrated in an in vitro study. But since the spectrum of the phototherapy lamps also includes ultraviolet lights, different from our study, the SCE changes that were observed in this study could have been occurred due to the ultraviolet light.
In contrast to all of these studies, we found that the laser application for epilation, the light given by which is in a spectrum between visible light and the infrared wavelength, does not cause genotoxic changes. This may be due to that the tissue absorption of laser does not differ according to the wavelength of the light and that the 755 nm wavelength of the device we used is more selective for melanin. But we could not meet any other study in the literature about the genotoxic effect of laser devices with other wavelengths, either. For this reason, we could not compare our results with the effects of laser applications at different wavelengths and this was an important limitation of our study.
Together with some recent studies, the permanent results obtained by the laser for the removal of unwanted hair as well as its use in the treatment of many dermatologic diseases because of its stimulating effect on collagen synthesis have been accepted as advantages of laser.  But, in spite of these favorable developments, what kind of effects the laser can have over apoptosis genes and DNA repair mechanisms is not known. There is no clear data about how the laser affects the surrounding tissues while targeting the hair roots. For this reason, further studies may be needed to clarify whether laser epilation procedures have an inducing effect on frequent cancers which originate from the skin appendages, and especially from the epithelium around the hair follicle such as basal cell carcinoma. For this purpose, studies that are performed on a greater number of patients with more intensive sequences and by the examination of skin biopsy samples may be more valuable. Since it will be unwise to perform biopsy for such a reason on human, in vivo studies performed on laboratory animals can be planned.
Although our study could not demonstrate an in vitro genotoxic effect of laser wavelength that is used for epilation procedures, our results need to be supported by studies that will be performed on different patient groups with a greater number of cases.
[1.] Zandi S, Lui H. Long-term removal of unwanted hair using light. Dermatol Clin. 2013; 1:179-91.
[2.] Anderson RR, Parrish JA. Selective photothermolysis: precise microsurgery by selective absorption of pulsed radiation. Science. 1983; 220:524-7.
[3.] Mortelmans K, Zeiger E. The Ames Salmonella/ microsome mutagenicity assay. Mutat Res. 2000; 455:29-60
[4.] Wilson DM, Thompson LH. Molecular mechanisms of sister-chromatid exchange. Mutat Res. 2007; 616:11-23.
[5.] Sachdeva S. Fitzpatrick skin typing: Applications in dermatology Indian J Dermatol Venereol Leprol. 2009; 75:1
[6.] Narurkar VA. Lasers, light sources, and radiofrequency devices for skin rejuvenation. Semin Cutan Med Surg. 2006; 25:145-50
[7.] Tanzi EL, Lupton JR, Alster TS. Lasers in dermatology: four decades of progress. J Am Acad Dermatol. 2003; 49:1-31; quiz 31-4
[8.] Uyar B, Saklamaz A. Effects of the 755-nm Alexandrite laser on fine dark facial hair: Review of 90 cases. J Dermatol. 2012; 39:430-2
[9.] Solarczyk KJ, Zar\ebski M, Dobrucki JW. Inducing local DNA damage by visible light to study chromatin repair. DNA Repair (Amst). 2012; 11(12):996-1002.
[10.] Kong X, Mohanty SK, Stephens J, Heale JT, GomezGodinez V, Shi LZ, Kim J, Yokomori K, Berns MW. Comparative analysis of different laser systems to study cellular responses to DNA damage in mammalian cells. Nucleic Acids Res. 2009; 37-68
[11.] Karadag A, Yesilyurt A, Unal S, Keskin I, Demirin H, Uras N, et al. A chromosomal-effect study of intensive phototherapy versus conventional phototherapy in newborns with jaundice. Mutat Res. 2009; 676:17-20
[12.] Dang Y, Liu B, Liu L, Ye X, Bi X, Zhang Y, et al. The 800nm diode laser irradiation induces skin collagen synthesis by stimulating TGF-(3/Smad signaling pathway. Lasers Med Sci. 2011; 26:837-43
Cite this article as: Ocak Z, Ozlu T, Tasdemir S, Bilen H, Kocaman E. Are there any genotoxic effects of laser epilation applications on human? An observational study.
Source of Support: Nil
Conflict of interest: None declared
Zeynep Ocak (1), Tulay Ozlu (2), Sener Tasdemir (3), Handan Bilen (4), Ertugrul Mevlut Kocaman (1)
(1) Department of Medical Genetics, Abant Izzet Baysal University Medical School, Bolu, Turkey
(2) Department of Obstetrics and Gynecology, Abant Izzet Baysal University Medical School, Bolu, Turkey
(3) Department of Medical Genetics, Ataturk University Medical School, Erzurum, Turkey
(4) Department of Dermatology, Ataturk University Medical School, Erzurum, Turkey
Zeynep Ocak (email@example.com)
Table-1: SCE Frequencies in the Groups during the Study Prior to Laser After Laser p-Value * Epilation Epilation Min-max-median 3.30-4.30-4.15 3.40-4.35-4.10 0.443 Wilcon Signed Ranks Test; SCE: sister chromatid exchange; * Value resembles all groups
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|Title Annotation:||RESEARCH ARTICLE|
|Author:||Ocak, Zeynep; Ozlu, Tulay; Tasdemir, Sener; Bilen, Handan; Kocaman, Ertugrul Mevlut|
|Publication:||National Journal of Physiology, Pharmacy and Pharmacology|
|Date:||Jan 1, 2014|
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