Penetration and haptenation of p-phenylenediamine

Hepatocellular carcinoma antibodies preferably identify nitro-oxidative-DNA lesions induced by 4-Chloro-orthophenylenediamine and DEANO

The widespread use of oxidative hair colouring cosmetics threatens public health. Phenylenediamine derivatives serve as the main pigment in permanent hair colours. They interact with biological macromolecules, altering their functional and structural physiology. The study aimed to investigate the effect of a typical synthetic hair dye pigment, 4-Chloro-orthophenylenediamine (4-Cl-OPD), under a nitrating environment of DEANO on the calf thymus DNA molecule. The results showed single-stranded regions, base/sugar-phosphate backbone alterations, molecular changes, and nitro-oxidative lesions. These modifications are referred to as neo-epitopes on the DNA molecule. IgGs from cancer patients with a history of permanent hair dye use were screened for the recognition of neo-epitopes on DNA molecules. Hepatocellular carcinoma IgG showed the highest binding with 56% inhibition in the competition ELISA. The immune complex formation was observed through electrophoretic mobility shift assay. In conclusion, synthetic hair dye users are likely to present with heightened immunological triggers under elevated nitric oxide levels. The study reports chronic hair dye exposure as one of the factors responsible for altering the intricacies of the DNA's microarchitectural structure and inducing neo-epitopes on the molecule. The physiological status of NO may define the susceptibility towards 4-Cl-OPD and humoral response in hair dye users. Persistent nitro-oxidative stress due to 4-Cl-OPD and NO may induce a heightened immune response against neoepitopes in the nitro-oxidatively modified DNA. Therefore, chronic hair dye exposure may be identified as a risk to human health. These findings may contribute to a better understanding and reinforcement of hair dye as one of the modifiable risk factors responsible for the pro-inflammatory carcinogenic environment.

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.

Genotoxicity of oxidative hair dye precursors: A systematic review

This systematic review, conducted according to the PRISMA guidelines, focuses on genotoxicity of oxidative hair dye precursors. The search for original papers published from 2000 to 2021 was performed in Medline, Web of Science, Cochrane registry, Scientific Committee on Consumer Safety of the European Commission and German MAK Commission opinions. Nine publications on genotoxicity of p-phenylenediamine (PPD) and toluene-2,5-diamine (p-toluylenediamine; PTD) were included, reporting results of 17 assays covering main genotoxicity endpoints. PPD and PTD were positive in bacterial mutation in vitro assay, and PPD tested positive also for somatic cell mutations in the Rodent Pig-a assay in vivo. Clastogenicity of PPD and PTD was revealed by in vitro chromosomal aberration assay. The alkaline comet assay in vitro showed DNA damage after PPD exposure, which was not confirmed in vivo, where PTD exhibited positive results. PPD induced micronucleus formation in vitro, and increased micronucleus frequencies in mice erythrocytes following high dose oral exposure in vivo. Based on the results of a limited number of data from the classical genotoxicity assay battery, this systematic review indicates genotoxic potential of hair dye precursors PPD and PTD, which may present an important health concern for consumers and in particular for professional hairdressers.

p-Phenylenediamine induces immediate contact allergy and non-histaminergic itch via MRGPRX2

p-phenylenediamine (PPD) is a common component of hair dye known to induce immediate allergy, even acute dermatitis and contact dermatitis. MAS-related G protein coupled receptor-X2 (MRGPRX2) in mast cells (MCs) mediates small molecular substances-induced pseudo-allergic reactions. However, the role of MRGPRX2 in PPD-induced immediate contact allergy needs further exploration. The aim of this study was to investigate whether PPD activates MCs via MRGPRX2 and induces immediate allergies that contribute to contact dermatitis. Wild-type (WT) and kitw-sh/w-sh mice (MUT) were treated with PPD to observe local inflammation and MC degranulation in vivo. The release of inflammatory mediators was measured in vitro. Histamine 1 receptor (H1R)-/- mice were used to analyze itch type. PPD caused immediate contact allergy in WT mice, induced scratching, and local inflammatory reactions, while exhibiting minimal effects on MUT mice. PPD did not induce histamine release, but induced significant tryptase release in vivo and in vitro. PPD activated MRGPRX2 to induce MC degranulation in vitro. PPD caused immediate contact allergy in WT mice, induced scratching and local inflammatory reactions, while exhibited minimal effect on MUT mice. PPD did not induce histamine release, while induced significant tryptase release in vivo and in vitro. PPD induced immediate contact allergy by MCs activation via MRGPRX2 and lead to tryptase release. The scratching times showed no significant difference in WT mice or H1R-/- mice, which indicated PPD caused non-histaminergic itch. The results showed that PPD activated MCs via MRGPRX2 and induced immediate contact allergy, leading to the release of tryptase without monoamine release, which might induce non-histaminergic itch.

Investigations on detoxification mechanisms of novel para-phenylenediamine analogues through N-acetyltransferase 1 (NAT-1)

Para-phenylenediamine (PPD) is one of the most used chemicals in oxidative hair dyes. However, its use has been associated with adverse effects on health, including contact dermatitis and other systemic toxicities. Novel PPD derivatives have been proposed as a safer replacement for PPD. This can be achieved if these molecules minimally permeate the skin and/or are easily metabolised by enzymes in the skin (e.g., N-acetyltransferase-1 (NAT-1)) into innocuous compounds before gaining systemic entry. This study investigated the detoxification pathway mediated by NAT-1 enzymes on 6 synthesized PPD analogues (namely, P1-P6) with different chemical properties, to study the role of functional groups on detoxification mechanisms in HaCaT skin cells. These compounds were carefully designed with different chemical properties (whereby the ortho position of PPD was substituted by nucleophile and electrophile groups to promote N-acetylation reactions, metabolism and clearance). Compounds P2-P4 N-acetylated at 54-49 nmol/mg/min, which is 1.6 times higher than N-acetylation of PPD, upregulated NAT-1 activity from 8-7% at 50 μM to 22-11% at 100 μM and showed 4 times higher rate of elimination (k equal to 0.141 ± 0.016-0.124 ± 0.01 h^-1) and 3 times faster rate of clearance (0.172 ± 0.007-0.158 ± 0.005 h^-1mgprotein^-1) than PPD (0.0316 ± 0.0019 h^-1, 0.0576 ± 0.003 h^-1mg protein^-1, respectively). The data suggest that nucleophile substituted compounds detoxify at a faster rate than PPD. Our metabolic and detoxification mechanistic studies revealed significantly higher rates of N-acetylation, NAT-1 activity and higher detoxification of P2-P4 in keratinocytes, suggesting the importance of nucleophilic groups at the ortho position in PPD to reduce toxicity of aniline-based dyes on human skin cells.

The expression pattern of N-acetyltransferase 1 in healthy human skin

Background

N‐acetyltransferase 1 (NAT1) is an enzyme expressed among others in keratinocytes in human skin. NAT1 is important in the biotransformation of aromatic amines, an important example being p‐phenylenediamine (PPD), a hair dye molecule. Unoxidized PPD penetrates the skin and is N‐acetylated by NAT1.

Objectives

To investigate in detail the expression pattern of NAT1 in human skin.

Materials and Methods

Cryosections obtained from healthy human skin were stained for NAT1 and expression patterns were observed. NAT1 double stainings were performed with antibodies against different cellular organelles to determine expression patterns.

Result

A speckled, granular expression of NAT1 was seen predominantly in the stratum basale. NAT1 was expressed in a cytoplasmic pattern, perinuclear, and in the nucleus. No co‐localisation was seen with the selected cellular organelles. Local differences in NAT1 expression patterns were observed between donors and between different biopsies obtained from the same donor.

Conclusions

NAT1 is expressed predominantly in the stratum basale and can be found in the cytoplasm, nucleus, and perinuclear in human skin. Further studies should be performed to investigate expression of NAT1 in a larger sample size.

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.

P-Phenylenediamine Hair Dye Allergy and Its Clinical Characteristics

Background

P-phenylenediamine (PPD) has been identified as the most frequent contact sensitizer of hair dye and the clinical characteristics of hair dye contact allergy (HDCA) are diverse.

Objective

The purpose of this study was to identify the clinical characteristics of HDCA and to assess the relationships between HDCA, exposure time to PPD and PPD positivity.

Methods

We analyzed 105 patients with patch test-confirmed hair dye allergy who presented between July 2009 and March 2015. Clinical symptoms, signs, associated skin diseases, involved ACD area, and patterns of hair dye use were obtained by reviewing medical records and by interview.

Results

HDCA was more common in women and in individuals aged more than 50 years. Pruritus was the most common symptom; erythematous macules and patches were the most frequently observed clinical signs. The most common site of HDCA was the face and non-specific eczema and urticaria were frequently observed with HDCA. Exposure time to hair dye, represented as frequency and duration, showed a positive correlation with the area affected by hair dye allergy (p<0.001). Hair dye allergy was identified in most patients (80%) before diagnosis by patch test. However, only 28.6% of all patients stopped using hair dye, even after the diagnosis was confirmed.

Conclusion

The extent of hair dye allergy involvement was related to exposure time to hair dye. For effective treatment of HDCA, it is important to properly educate patients with HDCA about the clinical manifestations of HDCA and to keep away from allergens.

Allergic Contact Dermatitis Due to Paraphenylenediamine: An Update

Paraphenylenediamine (PPD) is an amine that is mainly used as an ingredient in hair dyes and henna tattoos. The incidence of allergic contact dermatitis to PPD is increasing, particularly in younger patients. In this article, we review the main sources of PPD and the substances with which it can interact and present a practical algorithm for diagnosing and treating suspected cases of PPD allergy.

Biotransformation of 2,4-toluenediamine in human skin and reconstructed tissues

Reconstructed human epidermis (RHE) is used for risk assessment of chemicals and cosmetics and RHE as well as reconstructed human full-thickness skin (RHS) become important for e.g., the pre-clinical development of drugs. Yet, the knowledge regarding their biotransformation capacity is still limited, although the metabolic activity is highly relevant for skin sensitization, genotoxicity, and the efficacy of topical dermatics. The biotransformation of the aromatic amine 2,4-toluenediamine (2,4-TDA) has been compared in two commercially available RHS to normal human skin ex vivo, and in primary epidermal keratinocytes and dermal fibroblasts as well as in vitro generated epidermal Langerhans cells and dermal dendritic cells. The mono N-acetylated derivative N-(3-amino-4-methyl-phenyl)acetamide (M1) was the only metabolite detectable in substantial amounts indicating the predominance of N-acetylation. RHS exceeded human skin ex vivo in N-acetyltransferase activity and in cell cultures metabolite formation ranked as follows: keratinocytes > fibroblasts ~ Langerhans cells ~ dendritic cells. In conclusion, our results underline the principal suitability of RHS as an adequate test matrix for the investigation of N-acetylation of xenobiotics which is most relevant for risk assessment associated with cutaneous exposure to aromatic amines.

Real-time detection of p-phenylenediamine penetration into human skin by in vivo Raman spectroscopy

BACKGROUND

Penetration, autoxidation and N-acetylation of p-phenylenediamine (PPD) have been studied in vitro and ex vivo. However, a clear understanding of in vivo PPD penetration and the formation of PPD derivatives is lacking.

OBJECTIVES

To obtain insights into the in vivo penetration, clearance and formation of PPD derivatives in human skin.

METHODS

Patch test chambers containing PPD 1% pet. were applied to the forearms of two human volunteers, with increasing application times. Non-invasive Raman microspectroscopy was used for detection of PPD (derivatives) in skin at several follow-up times.

RESULTS

Application of a PPD 1% pet. patch for 30 min resulted in substantial amounts of PPD in the stratum corneum of 90 mg PPD/g keratin. PPD contents were highest after three applications for 1 h each (330 mg PPD/g keratin), followed by single applications for 2 h 40 min, 2 h, and 23 h. The PPD half-time in the skin was 3 h. No spectral contributions of Bandrowski's base, monoacetyl-PPD and diacetyl-PPD were detected.

CONCLUSIONS

We have gained insights into the in vivo penetration of PPD in human skin by using non-invasive Raman spectroscopy. Penetration into the skin was fast, and the PPD concentrations detected in the stratum corneum were high. PPD was detected in both the stratum corneum and the viable epidermis. Oxidized or acetylated PPD derivatives could not be detected.

Two sensitizing oxidation products of p-phenylenediamine patch tested in patients allergic to p-phenylenediamine

BACKGROUND

The results from a previous study indicated the presence of several possible sensitizers formed during oxidation of the potent sensitizer p-phenylenediamine (PPD) to which PPD-sensitized patients might react, in various patterns.

OBJECTIVES

To extract and analyse a yellow spot from a thin-layer chromatogram with oxidized PPD, to which 6 of 14 (43%) PPD-positive patients had reacted in a previous study, in order to identify potential sensitizer(s) and to patch test this/these substance(s) in the 14 PPD-positive patients.

METHODS

The yellow spot was extracted from a thin-layer chromatogram of oxidized PPD, and two substances, suspected to be allergens, were identified by analysis with gas chromatography mass spectrometry (GCMS). The 14 PPD-positive patients, who had been previously tested with the thin-layer chromatogram of oxidized PPD, participated in the investigation, and were tested with dilutions of the two substances.

RESULTS

GCMS analysis identified 4-nitroaniline and 4,4'-azodianiline in the yellow spot. Of the 14 PPD-positive test patients, 5 (36%) reacted to 4-nitroaniline and 9 (64%) reacted to 4,4'-azodianiline.

CONCLUSION

The results show that 4-nitroaniline and 4,4'-azodianiline, formed during oxidation of PPD, are potent sensitizers. PPD-sensitized patients react to a high extent to concentrations equimolar to PPD of 4-nitroaniline and 4,4'-azodianiline.

Analysis of the Results from the Patch Test to Para-Phenylenediamine in the TRUE Test in Patients with a Hair Dye Contact Allergy

Background

Para-phenylenediamine (PPD) is the primary patch test screening agent for hair dye contact allergy (HDCA). However, no recent studies have been published that describe the results of reactions to patch tests using PPD and hair dyes in Korea.

Objective

To analyze the results of the patch tests to PPD using the thin-layer rapid use epicutaneous (TRUE) Test system in patients with HDCA and to investigate patients' awareness that hair dyes contains allergens, which cause the development of HDCA.

Methods

Eighty-four patients with suspected HDCA (32 men and 52 women) underwent patch testing using the TRUE Test system and their own hair dyes. The patients' demographic data, behavior associated with hair dyeing, and clinical manifestations of HDCA were examined retrospectively.

Results

Positive patch-test reactions to hair dyes occurred in 53.6% of patients who used hair dyes, and they were diagnosed with HDCA. Although there was a significant correlation between HDCA and PPD sensitization (p=0.001), only 40% of the patients with HDCA showed positive reactions to PPD. Of the 45 patients diagnosed with HDCA, only 7 (15.6%) were aware that their hair dyes contained allergens that caused HDCA.

Conclusion

This study's findings show that PPD is an effective HDCA marker. However, we propose that investigations on hair dye components other than PPD should be conducted to develop and validate additional predictive HDCA markers.

Cross-elicitation responses to 2-methoxymethyl-p-phenylenediamine under hair dye use conditions in p-phenylenediamine-allergic individuals

BACKGROUND

The factors influencing elicitation responses in individuals allergic to p-phenylenediamine (PPD) in hair dyes are not well understood.

OBJECTIVES

Investigation of the elicitation response to the new, less-sensitizing PPD alternative 2-methoxymethyl-p-phenylenediamine (ME-PPD) under simulated hair dye use conditions.

METHODS

The cross-elicitation response to ME-PPD (2% in a hair dye test product for 30 min on forearm then rinsing) was analysed at days 2 and 3 in 30 PPD-allergic individuals with diagnostic patch test grades +, ++ or +++ according to the classification of the International Contact Dermatitis Research Group.

RESULTS

Cross-reactivity to the ME-PPD-containing hair dye test product was elicited in nine of 30 subjects (30%), while 70% were negative. Cross-reactivity was elicited in two of four cases with grade +++, three of 10 with grade ++ and four of 16 with grade +. Under identical conditions, PPD was previously found to elicit a response in 21 of 27 PPD-allergic individuals. In 18 of these 21 individuals, either the strength of the cross-elicitation response to ME-PPD was decreased or no response occurred.

CONCLUSIONS

Under simulated hair dye use conditions, a significantly lower degree of cross-elicitation to ME-PPD (30%) was observed than previously reported for PPD (32 of 38, 84%). Additionally, a decreased cross-elicitation strength was observed across all three patch test grades, likely reflecting the reduced skin-sensitization properties of ME-PPD. Consequently, careful dermatological evaluation is required to assess cross-reactivity to ME-PPD in patients allergic to hair dyes.

The importance of hapten-protein complex formation in the development of drug allergy

PURPOSE OF REVIEW

Drug allergy is an adverse drug reaction that is immune-mediated. Immune activation can occur when drugs or haptens bind covalently to proteins and then act as antigens. The purpose of this review is to summarize the recent data on the formation of hapten-protein complexes and to assess the importance of these complexes in the generation of drug allergy.

RECENT FINDINGS

The formation of hapten-protein complexes by drugs and their reactive metabolites has largely been investigated using model proteins such as human serum albumin. Precise identification of the structure of the hapten and the resulting modified residue(s) in the protein has been undertaken for a small number of drugs, such as p-phenylenediamine, nevirapine, carbamazepine, β-lactams and abacavir. Some progress has also been made in identifying hapten-protein complexes in the serum of patients with allergy.

SUMMARY

Drug-specific T cells have been isolated from different patients with allergy. Formation of hapten-protein complexes, their processing and antigen presentation have been implicated in the development of drug allergy to p-phenylenediamine, sulfonamides and β-lactams. However, evidence also supports the pi mechanism of immune activation wherein drugs interact directly with immune receptors. Thus, multiple mechanisms of immune activation may occur for the same drug.