Paraphenylene diamine, a contact allergen, induces oxidative stress in normal human keratinocytes in culture

Ecotoxicity, Health Risks and Contact Allergy Due to p-Phenylenediamine in Hair Dyes and Tattoos: Female Students' Perspectives

While the financial advantages of hair coloring and tattooing are widely acknowledged, environmental hazards and health risks linked to this trend due to their p-phenylenediamine (PPD) content have received less attention. Health education on hair-dying products is warranted to enhance the public's awareness of hair-dying ingredients and their side effects.  A cross-sectional study was therefore conducted with 319 students to assess knowledge of ecotoxicity, health risks, and practices of hair dyeing and tattooing among undergraduate students. A random sample of 59 students was checked for any allergic morphology in the scalp and exposed areas of skin near the neck, ears, palms, and nails. Responses collected were used for data analyses using IBM SPSS Statistics for Windows, Version 17 (Released 2008; IBM Corp., Armonk, New York, United States). Use of hair dye was significantly high among study participants 58.5% (n=187; p<0.05). However, their knowledge regarding the presence of PPD in hair dyes and associated environmental toxicity (37.8%, n=121) was very limited. The majority of participants did not do any allergy tests before applying hair dye (88.9%, n=283). The study revealed that the main reason for hair coloring was as a fashion statement (93.7%, n=299). Regarding tattooing practices, 96.9% (n=309) of study participants had never practiced tattoos, and hence, the prevalence of tattooing was 3.9% (n=12). These data confirmed that the practice of hair dyeing as a style statement was high among students. However, the majority were unaware of their PPD contents and their potential ecotoxicity and health risks.

Rhus semialata M. extract ameliorate para-phenylenediamine-induced toxicity in keratinocytes

para-Phenylediamine (PPD), a major component of hair dyeing ingredients, can induce allergenic sensitization and exert mutagenic, tumorigenic and cytotoxic effect. In this study, we determined the cytotoxic effect of PPD on human keratinocytes and evaluated the protective effect of Rhus semialata M. extracts (RSE) on PPD induced cytotoxicity for the first time. We observed that RSE is a strong inhibitory agent against PPD-induced toxicity in human keratinocytes. The results indicated that RSE pretreatment significantly could suppress PPD induced cytotoxic effects, including decrease of cell viability, accumulation in subG1 phase of cells, and relocation of phosphatidylserine on keratinocytes. Also, we found that PPD caused cytotoxicity was associated with mitochondrial membrane potential loss and subsequent activation of caspase and PARP degradation. However, pretreatment of RSE showed preventive activities against PPD induced mitochondrial membrane potential loss and ROS production in keratinocytes. In conclusion, the results of present study suggest that RSE was able to protect the skin from several cytotoxic effects of PPD and could be a meaningful material in many industries using PPD.

The effects of para-phenylenediamine (PPD) on the skin fibroblast cells

1. Para-phenylenediamine (PPD) is the commonest and most well-known component of hair dyes. PPD is found in more than 1000 hair dye formulations and is the most frequently used permanent hair dye component in Europe, North America and East Asia. PPD containing hair dyes have been associated with cancer and mutagenicity. Apart from that, PPD has potential toxicity which includes acute toxicity such as allergic contact dermatitis and subacute toxicity. 2. In this study, we examined the effects of the PPD composition on the skin-isolated fibroblast cells. Fibroblast cells were isolated from the skin and cell viability, reactive oxygen species (ROS) production, the collapse of mitochondrial membrane potential (MMP), lipid peroxidation (LPO), damage to the lysosome release of lactate dehydrogenase (LDH) and finally release of cytochrome c were examined following the exposure to various concentrations of PPD. 3. Our results showed that exposure to PPD increased ROS generation, LPO, the collapse of MMP, LDH release and cytochrome c release. Our results suggest that PPD can induce damage to the lysosomal membrane. 4. These results showed that PPD composition has a selective toxicity on skin fibroblasts cell and mitochondria are considered one of the goals of its toxicity.

The oxidation of p-phenylenediamine, an ingredient used for permanent hair dyeing purposes, leads to the formation of hydroxyl radicals: Oxidative stress and DNA damage in human immortalized keratinocytes

The hair-dyeing ingredient, p-phenylenediamine (PPD), was previously reported to be mutagenic, possibly by inducing oxidative stress. However, the exact mechanism of PPD in inducing oxidative stress upon skin exposure during hair-dyeing in human keratinocytes remains unknown. The aim of our studies was therefore to investigate the toxicity of PPD and its by-products in human immortalized keratinocytes (HaCaT) after auto-oxidation and after reaction with hydrogen peroxide (H2O2). We found that the PPD half maximal effective cytotoxic concentration (EC50) to HaCaT is 39.37 and 35.63 μg/mL after 24 and 48 h, respectively, without addition of H2O2 to induce oxidation. When PPD (10 or 100 μg/mL) is combined with 10.5 μg/mL of H2O2, intracellular ROS production by HaCaT after 1 h was significantly increased and enhanced levels of DNA damage were observed after 4 h of exposure. After 24 h incubations, 20 μg/mL of PPD increased the level of DNA oxidation in HaCaT. Also, we found that the in vitro reaction between PPD and H2O2, even below the maximum allowance by cosmetic industries, released hydroxyl radicals which can damage DNA. Taken together, we conclude that PPD alone and when combined with H2O2 increases the formation of reactive oxygen species in human keratinocytes, leading to oxidative stress and subsequent DNA damage. These alterations suggest that the mechanism by which PPD exposure, alone or combined with H2O2, damages keratinocytes by the formation of the high reactive HO∙ radicals.

Evaluation of trace elements, oxidant/antioxidant status, vitamin C and β-carotene in dogs with dermatophytosis

The aim of the study was to determine zinc, copper and iron levels, erythrocyte oxidant/antioxidant status, vitamin C and β-carotene in dogs with dermatophytosis. A total of 23 dogs with clinically established diagnosis of dermatophytosis by trichogram and positive fungal culture and six dogs as control were included in this study. On cultural examination 52.17% fungal isolates were found to be Microsporum canis, 30.43% were Trichophyton mentagrophytes and 17.39% were M. gypseum. In comparison to healthy control, the dogs with dermatophytosis had significantly lower levels of zinc (P < 0.01), copper (P < 0.05), β-carotene and vitamin C levels (P < 0.05) and activities of superoxide dismutase (SOD) (P < 0.05) and catalase (P < 0.01), whereas the iron (P < 0.05) and malondialdehyde (MDA) (P < 0.01) levels were significantly increased. On correlation analysis, SOD activity was observed to be positively correlated (P < 0.05) with zinc and copper in both healthy and dermatophytosis affected dogs. In dermatophytosis affected dogs the MDA levels were negatively correlated (P < 0.05) with iron, β-carotene levels and the activities of antioxidant enzymes; SOD and catalase. Our results demonstrated that dermatophytosis in dogs is associated with significant alteration in oxidant/antioxidant balance and trace elements. It might be secondary consequence of dermatophytosis infection or contributing factor in its pathogenesis.

An experimental model of contact dermatitis: evaluation of the oxidative profile of Wistar rats treated with free and nanoencapsulated clobetasol

OBJECTIVE

An experimental animal model of contact dermatitis (CD) was used to investigate the effects of free and nanoencapsulated clobetasol propionate on the skin and on the oxidative profile of liver tissue.

METHODS

Female Wistar rats were divided into six groups, each containing eight rats. The first group, control (C), was sensitized with solid vaseline. Group 2, (CD), was sensitized with 5% NiSO(4). Groups 3 and 4 were sensitized with 5% NiSO(4) and treated with free (FC) and nanoencapsulated (NC) clobetasol (0.42 mg/g), respectively, daily for 5 days. Group 5 was treated with nanoencapsulated clobetasol (0.42 mg/g) on days 1, 3, and 5 (C135) and group 6 received a hydrogel containing empty nanoparticles (NP) daily for 5 days. Thiobarbituric acid reactive substances (TBARS), carbonyl levels, non-protein sulfhydryl groups (NPSH) and catalase activity were measured in liver homogenates.

RESULTS

A significant increase was observed in the levels of TBARS, NPSH, and catalase activity for the groups CD and NP.

DISCUSSION

Our results suggest that both NiSO(4) sensitization and NP administration induced oxidation of cellular lipids and activated the antioxidant enzyme catalase to protect from this damage. These results also indicated that daily treatment with the free and nanoencapsulated clobetasol, as well as treatment with the nanoencapsulated clobetasol every other day, were able to prevent these redox alterations and protect against histological damage.

p-Phenylenediamine allergy: the role of Bandrowski's base

p-Phenylenediamine (PPD) is a commonly used hair-dye and a potent skin allergen. The mechanism of sensitization is unknown, as PPD is protein unreactive. We studied Bandrowski's base (BB), a PPD trimer, as well as 1,4-benzoquinone (BQ), a PPD hapten. PPD patch-test positive patients were patch-tested to BB and BQ. All tests were negative to 0.01% BQ and 0.01% BB. Five of 14 (35.7%) tested had true positive reactions to 0.1% BQ. One percent BQ was found to be irritant. Seven of 43 tested (16%) were positive to either 0.1% or 1% BB. The positive reactions to BB were weak, even when PPD reactions were strong. Mice lymph node assay gave EC3 values of 0.14% for PPD compared with 0.03% for BB. Therefore, BB is approximately 10 times more potent than PPD, taking into account the molarity. We suggest that while PPD may act as a prohapten, there is probably a spectrum of antigenic determinants in vivo. BB may be bound or metabolized by keratinocytes before it reacts with Langerhans cells.

DNA damage and TNFalpha cytokine production in hairdressers with contact dermatitis

The present work was undertaken to study in hairdressers exposed to several irritants and allergens (prevalently hair-dyeing) and affected by hand contact dermatitis the possible correlation between exposure and direct-oxidative DNA damage, production of tumour necrosis factor alpha (TNFalpha) and allergic inflammatory disease. We evaluated in 19 hairdressers with hand contact dermatitis, 14 allergic contact dermatitis (ACD) and 5 irritant contact dermatitis (ICD) and in a selected control group TNFalpha serum levels by ELISA and direct-oxidative DNA damage by Fpg (formamido-pyrimidine-glycosylase)-modified Comet test on blood. Hairdressers were divided on the basis of number of hair-dyeing carried out weekly into 2 groups: low-exposure (<60 hair-dyeing/week) and high-exposure hairdressers (>or=60 hair-dyeing/week) that reflect also the exposure to other allergens and irritants and 2 different tasks (hairdressers and apprentice hairdressers, respectively). Serum levels of TNFalpha in hairdressers with ACD were significantly higher than controls with a correlation to exposure level. Significant DNA damage in ICD hairdressers with higher exposure as compared to controls was found. These findings suggest that occupational exposure can induce in hairdressers, particularly ICD, DNA damage, increase the TNFa levels particularly in ACD and induce allergic sensitization, suggesting a relationship between direct-oxidative DNA damage, TNFalpha production and allergic inflammatory disease.

Dermatotoxicity of epicutaneously applied anticoagulant warfarin

Dermatotoxic effects of epicutaneous application of a first-generation anticoagulant, warfarin (WF) were examined in rats. Selected parameters of skin activity were determined 24h following warfarin application, including metabolic viability of skin explants, some aspects of oxidative activity in skin tissue homogenates and inflammatory/immune relevant activity of epidermal cells from warfarin-treated skin. No changes in skin metabolic viability (MTT reduction) were noted ex vivo following WF application, suggesting the absence of immediate toxicity for skin. In contrast, increased formation of malondialdehyde (MDA), with a decrease in protein and non-protein thiols in homogenates of warfarin-treated skin was demonstrated, pointing to prooxidant activity in warfarin-treated skin. Increased costimulatory activity of epidermal cells isolated from warfarin-exposed skin in Con-A-stimulated T-cell activation/proliferation assay was noted, reflecting proinflammatory and immune-modulating capacity of warfarin for epidermis. No evident differences in skin histology between control and warfarin-treated skin were found at that time point, while striking changes in tissue integrity, cellularity and appearance 72 h following WF application were noted. The observed histological picture probably reflects a regenerative/inflammatory program related to oxidant/inflammation-type warfarin-evoked injury to the skin. Presented data demonstrate the potential of epicutaneously applied warfarin to modulate local skin activity in rats.

Allergic contact dermatitis is accompanied by severe abnormal changes in antioxidativity of blood

We investigated whether the oxidative stress (OS) caused by skin inflammation could reflect in the blood, in a 21-year-old female student sensitized to nickel, colophony and abitole with often relapsing allergic contact dermatitis (ACD). As glutathione redox ratio was increased in the blood not only during the relapse but also in the beginning of remission phase, we prescribed natural medical preparations of d-alpha-tocopherol (in the first week 100 mg three times a day followed by 100 mg/day) and ascorbic acid (200 mg/day) for 25 days to her. After using antioxidants in the remission period, one of the principal OS markers-the glutathione redox ratio reached the normal physiological level. In this report, we showed that during acute extensive ACD OS is expressed in the blood and simultaneous supplementation of d-alpha-tocopherol and ascorbic acid might reduce systemic OS.

Patients with allergic and irritant contact dermatitis are characterized by striking change of iron and oxidized glutathione status in nonlesional area of the skin

To assess the consequences of oxidative stress in allergic and irritant contact dermatitis, we compared the iron level, unsaturated iron-binding capacity, total iron binding capacity, the percentage saturation of iron-binding capacity, the amount of diene conjugates as well as the amounts of total glutathione, reduced glutathione, oxidized glutathione, and the oxidized glutathione/reduced glutathione ratio in skin homogenate from lesional and nonlesional skin. Lesional skin samples were obtained from positive patch test sites to 5% NiSO4 in five subjects, and from chronic contact dermatitis lesions on the hands, which had exacerbated over 3--9 wk in six subjects. Contact dermatitis caused at least a 4-fold increase in the iron level in the lesional skin area compared with the nonlesional skin area (p < 0.02). The increase in the iron level depended on the duration of contact dermatitis and was accompanied by high unsaturated iron-binding capacity and total iron-binding capacity values in the positive patch test sites (p < 0.05), and by a high percentage saturation value in the chronic contact dermatitis lesions (p < 0.05). We found high indices for iron, total iron-binding capacity and diene conjugates in the apparently healthy skin of the patients with persistent contact dermatitis that significantly (p < 0.05) exceeded the corresponding values in the patients with only patch test reactions. In summary, we have succeeded in providing evidence that generalized oxidative damage of the skin occurs as a consequence of contact dermatitis in a restricted area.

Activation of oral keratinocytes by mercuric chloride: relevance to dental amalgam-induced oral lichenoid reactions

BACKGROUND

Despite the benefits of mercury-containing amalgam dental fillings there are growing concerns regarding the potential adverse health effects arising from exposure to mercury released from fillings. In some individuals this process may result in a local lichenoid reaction of the oral mucosa.

OBJECTIVES

The aim of this study was to investigate the possibility that mercury salts released from amalgam fillings might act directly on oral keratinocytes to induce changes that could promote the development of such lesions.

METHODS

In vitro experiments were performed in which normal oral and cutaneous keratinocytes were cultured in the presence of mercuric chloride (HgCl2). ICAM-1 expression and the release of cytokines was determined by enzyme-linked immunosorbent assay techniques. T-cell binding to HgCl2-pretreated keratinocytes was assessed using a colorimetric method.

RESULTS

Subcytotoxic concentrations of HgCl2 induced a concentration-related increase in ICAM-1 expression and consequent T-cell binding on oral, but not cutaneous, keratinocytes. HgCl2 also stimulated the release of low levels of tumour necrosis factor-alpha and interleukin-8 (but not RANTES), and inhibited the release of interleukin-1alpha by oral keratinocytes.

CONCLUSIONS

This study provides evidence that oral keratinocytes may play an integral part in initiating the pathogenesis of amalgam-induced lichenoid reactions.

The participation of proliferative keratinocytes in the preimmune response to sensitizing agents

The aims of this study were to investigate whether keratinocytes are capable of playing a direct preimmune role in the pathophysiology of allergic contact dermatitis (ACD) and to examine to what extent the degree of differentiation might influence this. We measured the ability of sensitizing agents to up-regulate intercellular adhesion molecule 1 (ICAM-1) expression in cultured normal human keratinocytes (NHK) and in the transformed human keratinocyte HaCaT cell line. In proliferative HaCaT cells, following a 24 h exposure, nickel compounds, para-phenylenediamine (pPD) and 1-chloro-2,4-dinitrobenzene produced a concentration-dependent up-regulation of ICAM-1 expression without reducing cell viability, while K2Cr2O7 led to ICAM-1 up-regulation at cytotoxic concentrations, and CrCl3 was without effect. In NHK, NiSO4 and pPD induced ICAM-1 expression to a significantly greater extent in proliferative cells than in differentiated cells, where involucrin expression was measured to assess the differentiation state. NiSO4- or pPD-pretreatment of proliferative HaCaT cells enhanced T-cell binding, which was abolished by neutralizing antibodies to ICAM-1 or CD18. Our investigations concerning the involvement of oxidative stress in the induction of ICAM-1 expression in response to sensitizing agents were inconclusive. The oxidizing agents FeCl3 and H2O2 up-regulated ICAM-1 expression in HaCaT cells but there was no clear relationship between the ability of agents to induce ICAM-1 expression and their ability to alter the levels of reduced glutathione. Although pPD increased interleukin-1 alpha release from NHK, this cytokine was not capable of inducing ICAM-1 expression in NHK. Tumour necrosis factor-alpha, which does induce ICAM-1 expression in NHK, was not detected in response to pPD, arguing against an autocrine pathway of ICAM-1 induction in response to pPD. In summary, we report the direct interaction of sensitizing agents with keratinocytes leading to the generation of immune signals, particularly by proliferative keratinocytes, suggesting an active role for the proliferative keratinocyte in the pathophysiology of ACD.