Gene expression profiling of hair-dying agent, para-phenylenediamine, in human keratinocytes (HaCaT) cells

Accuracy of Rapid Emergency Medicine Score and Sequential Organ Failure Assessment Score in predicting acute paraphenylenediamine poisoning adverse outcomes

Paraphenylenediamine (PPD) is a commonly used xenobiotic in hair dying, causing deleterious outcomes in acute poisoning. Although many epidemiological studies and case reports explained their clinical presentations and fatal consequences, no studies have evaluated the early determinants of adverse outcomes. Therefore, the present study aimed to assess the initial predictors of acute PPD poisoning adverse outcomes, focusing on the discriminatory accuracy of the Rapid Emergency Medicine Score (REMS) and Sequential Organ Failure Assessment (SOFA) score. A retrospective cohort study included all acute PPD-poisoned patients admitted to three Egyptian emergency hospitals from January 2020 to January 2022. Data was gathered on admission, including demographics, toxicological, clinical, scoring systems, and laboratory investigations. Patients were categorized according to their outcomes (mortality and complications). Ninety-seven patients with acute PPD poisoning were included, with a median age of 23 years, female predominance (60.8%), and suicidal intention (95.9%). Out of all patients, 25.77% died, and 43.29% had complicated outcomes. Respiratory failure was the primary cause of fatalities (10.30%), while acute renal failure (38.14%) was a chief cause of complications. The delay time till hospitalization, abnormal electrocardiogram, initial creatine phosphokinase, bicarbonate level, REMS, and SOFA scores were the significant determinants for adverse outcomes. The REMS exhibited the highest odds ratio (OR = 1.91 [95% confidence interval (CI): 1.41-2.60], p < 0.001) and had the best discriminatory power with the area under the curve (AUC) = 0.918 and overall accuracy of 91.8% in predicting mortality. However, the SOFA score had the highest odds ratio (OR = 4.97 [95% CI: 1.16-21.21], p = 0.001) and only yielded a significant prediction for complicated sequels with AUC = 0.913 and overall accuracy of 84.7%. The REMS is a simple clinical score that accurately predicts mortality, whereas the SOFA score is more practicable for anticipating complications in acute PPD-poisoned patients.

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 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.

Implication of microRNA regulation in para-phenylenediamine-induced cell death and senescence in normal human hair dermal papilla cells

Para-phenylenediamine (PPD) is a major component of hair coloring and black henna products. Although it has been largely demonstrated that PPD induces allergic reactions and increases the risk of tumors in the kidney, liver, thyroid gland and urinary bladder, the effect on dermal papilla cells remains to be elucidated. Therefore, the current study evaluated the effects of PPD on growth, cell death and senescence using cell-based assays and microRNA (miRNA) microarray in normal human hair dermal papilla cells (nHHDPCs). Cell viability and cell cycle analyses demonstrated that PPD exhibited a significant cytotoxic effect on nHHDPCs through inducing cell death and G₂ phase cell cycle arrest in a dose-dependent manner. It was additionally observed that treatment of nHHDPCs with PPD induced cellular senescence by promoting cellular oxidative stress. In addition, the results of the current study indicated that these PPD-mediated effects were involved in the alteration of miRNA expression profiles. Treatment of nHHDPCs with PPD altered the expression levels of 74 miRNAs by ≥2-fold (16 upregulated and 58 downregulated miRNAs). Further bioinformatics analysis determined that these identified miRNA target genes were likely to be involved in cell growth, cell cycle arrest, cell death, senescence and the induction of oxidative stress. In conclusion, the observations of the current study suggested that PPD was able to induce several cytotoxic effects through alteration of miRNA expression levels in nHHDPCs.

A comparative study of the infrared and Raman spectra of aniline and o-, m-, p-phenylenediamine isomers

The structural stabilities of o-, m- and p-phenylenediamine (PDA) isomers were investigated by DFT-B3LYP and ab initio MP2 calculations with the 6-311G(**) basis set. From the calculations the three isomers were predicted to exist predominantly in an anti (transoid) structure. In the o-isomer, the syn (cisoid) form is calculated to turn to the anti (transoid) form with the two HNCC torsional angles of about 44 and 10° and the NH2 inversion barrier of 3-4 kcal/mol. The CCNH torsional angles in the m-PDA and p-PDA isomers were calculated to be about 25-26° as compared to 20° in aniline. A comparison of the Raman spectra of the three PDA-s with those of aniline shows the high sensitivity of the ring breathing mode to the nature of substituents in the aniline ring. The vibrational wavenumbers were computed at the DFT-B3LYP for aniline and the o-, m- and p-PDA isomers for the purpose of comparison. Complete vibrational assignments were made on the basis of normal coordinate analyses and potential energy distributions for aniline and the o-, m- and p-PDA molecules.

Colitis-accelerated colorectal cancer and metabolic dysregulation in a mouse model

The connection between inflammation and colorectal cancer (CRC) has been well recognized, and numerous related molecular mechanisms have been uncovered. To gain further insight, we used BALB/c mice treated with azoxymethane (AOM) and dextran sulfate sodium salt (DSS) to establish a colitis-associated CRC model recapitulating tubulovillous adenoma with high-grade dysplasia at week 14. We evaluated the mice in four groups: a control group fed a standard diet; a group given DSS, in which we observed no tumor or dysplasia; a group given AOM, in which we observed few dysplastic foci despite repeated administrations of the carcinogen and a group given both AOM and DSS, in which our observations agreed with those of other studies that found accelerated colorectal carcinogenesis following DSS-induced colitis. We examined the messenger RNA and micro RNA (miRNA) expression profiles of the four groups. In colitis-associated CRC, we observed the dysregulation of many pathways, including the upregulation of Wnt signaling and CRC pathways and the downregulation of apoptosis. Also, most differentially expressed genes were significantly enriched in metabolic rather than immune/inflammation pathways/processes. Additionally, we demonstrated that the expression of several important miRNAs involved in both the inflammatory response and metabolism was dramatically altered during colitis-associated CRC. Gene network analysis and gene profile analysis confirmed a close relationship between metabolic and inflammatory genes in colitis-associated CRC. Thus, our study may provide a framework for identifying metabolic genes as targets of novel molecular-based therapies against CRC.