Profiling steroid and thyroid hormones with hair analysis in a cohort of women aged 25 to 45 years old.

Objective: Endogenous hormones regulate numerous physiological processes in humans. Some of them are routinely measured in blood, saliva and/or urine for the diagnosis of disorders. The analysis of fluids may, however, require multiple samples collected at different time points to avoid the high variability in the concentration of some hormones. In contrast, hair analysis has been proposed as an interesting alternative to reveal average hormone levels over a longer period. In this work, we developed and validated an analytical method for analyzing 36 endogenous steroid and thyroid hormones and one pineal hormone in human hair using ultra-performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS). Methods: Sample preparation involved hair decontamination, pulverization, methanol extraction, and purification with C18-solid phase extraction. Extracts were then divided into two portions, respectively injected into an UPLC-MS/MS system, and analyzed using two different instrumental methods. The method was applied to a healthy female population aged 25-45 years. Results: The method was validated on supplemented hair samples for the 37 targeted hormones, and its application to the population under study allowed to detect 32 compounds in 2-100% of the samples. Complete reference intervals (2.5-97.5th percentiles) were established for estrone, 17ß-estradiol, androstenedione, dehydroepiandrosterone, progesterone, 17α-hydroxyprogesterone, cortisone, cortisol and 3,3',5-triiodo-L-thyronine. Hair cortisone, cortisol, tetrahydrocortisone and tetrahydrocortisol concentrations were highly correlated with each other, with Kendall's τ correlation coefficients ranging from 0.52 to 0.68. Conclusion: Allowing the detection of 32 hormones from different chemical classes, the present method will allow to broaden hormonal profiling for better identifying endocrine disorders.

Mechanisms involved in the death of steatotic WIF-B9 hepatocytes co-exposed to benzo[a]pyrene and ethanol: a possible key role for xenobiotic metabolism and nitric oxide.

We previously demonstrated that co-exposing pre-steatotic hepatocytes to benzo[a]pyrene (B[a]P), a carcinogenic environmental pollutant, and ethanol, favored cell death. Here, the intracellular mechanisms underlying this toxicity were studied. Steatotic WIF-B9 hepatocytes, obtained by a 48h-supplementation with fatty acids, were then exposed to B[a]P/ethanol (10 nM/5 mM, respectively) for 5 days. Nitric oxide (NO) was demonstrated to be a pivotal player in the cell death caused by the co-exposure in steatotic hepatocytes. Indeed, by scavenging NO, CPTIO treatment of co-exposed steatotic cells prevented not only the increase in DNA damage and cell death, but also the decrease in the activity of CYP1, major cytochrome P450s of B[a]P metabolism. This would then lead to an elevation of B[a]P levels, thus possibly suggesting a long-lasting stimulation of the transcription factor AhR. Besides, as NO can react with superoxide anion to produce peroxynitrite, a highly oxidative compound, the use of FeTPPS to inhibit its formation indicated its participation in DNA damage and cell death, further highlighting the important role of NO. Finally, a possible key role for AhR was pointed out by using its antagonist, CH-223191. Indeed it prevented the elevation of ADH activity, known to participate to the ethanol production of ROS, notably superoxide anion. The transcription factor, NFκB, known to be activated by ROS, was shown to be involved in the increase in iNOS expression. Altogether, these data strongly suggested cooperative mechanistic interactions between B[a]P via AhR and ethanol via ROS production, to favor cell death in the context of prior steatosis.

Determination of farm workers' exposure to pesticides by hair analysis.

In the present work, a highly sensitive method based on solid phase microextraction and gas chromatography tandem (triple quadrupole) mass spectrometry was used to test hair samples for 50 pesticides including 39 molecules from different chemical families currently used in agriculture and 11 organochlorines. The population investigated was composed of 18 farm workers who provided hair samples repeatedly collected during the entire treatment period (from March to November 2009). Among the 62 hair samples that were collected, 33 different target molecules were detected. The most frequently detected agricultural pesticides were Diflufenican and Pyrimethanil, two herbicides which were detected in 13 subjects. The concentration in volunteers' hair matched with agricultural activity and the highest concentration was observed for Cyprodinil (1161pg/mg), an anilinopyrimidine used as a fungicide. For organochlorines, p,p'-DDE and γ-HCH were the most frequently detected molecules as they were present in at least one of the hair samples provided by each of the 18 volunteers. The highest concentrations detected for these chemicals reached 21.0pg/mg for p,p'-DDE and 23.5pg/mg for γ-HCH, but the highest concentration of organochlorine was observed for ß-endosulfan (105pg/mg). The results suggest that farm workers have a weak, though constant exposure to organochlorine pesticides, especially to p,p'-DDE and γ-HCH, while exposure to currently used pesticides is strongly associated with occupation. Observations also suggest that spraying work would not necessarily be the only source of exposure to agricultural pesticides and that worker not directly involved in spraying can also be submitted to significant level of exposure.