Exposure to tungsten particles via inhalation triggers early toxicity marker expression in the rat brain.

OBJECTIVE: Our work is focused on tungsten, considered as an emerging contaminant. Its environmental dispersion is partly due to mining and military activities. Exposure scenario can also be occupational, in areas such as the hard metal industry and specific nuclear facilities. Our study investigated the cerebral effects induced by the inhalation of tungsten particles. METHODS: Inhalation exposure campaigns were carried out at two different concentrations (5 and 80 mg/m3) in single and repeated modes (4 consecutive days) in adult rats within a nose-only inhalation chamber. Processes involved in brain toxicity were investigated 24 h after exposure. RESULTS AND DISCUSSION: Site-specific effects in terms of neuroanatomy and concentration-dependent changes in specific cellular actors were observed. Results obtained in the olfactory bulb suggest a potential early effect on the survival of microglial cells. Depending on the mode of exposure, these cells showed a decrease in density accompanied by an increase in an apoptotic marker. An abnormal phenotype of the nuclei of mature neurons, suggesting neuronal suffering, was also observed in the frontal cortex, and can be linked to the involvement of oxidative stress. The differential effects observed according to exposure patterns could involve two components: local (brain-specific) and/or systemic. Indeed, tungsten, in addition to being found in the lungs and kidneys, was present in the brain of animals exposed to the high concentration. CONCLUSION: Our data question the perceived innocuity of tungsten relative to other metals and raise hypotheses regarding possible adaptive or neurotoxic mechanisms that could ultimately alter neuronal integrity.

Distribution of novel immune-checkpoint targets in ovarian cancer tumor microenvironment: A dynamic landscape.

BACKGROUND: The disappointing activity of single agent immune-checkpoint inhibitors in epitherlial ovarian cancer (EOC) has been attributed in part to its unique tumor microenvironment (TME). IDO, PDL1, LAG3 and TIM3 have been implicated in the immunotolerance of EOC. We investigated the expression of these co-regulators, their change with neoadjuvant chemotherapy (NACT), and their association with outcome. METHOD: We identified 98 patients with EOC treated with NACT and performed IDO, PDL1, LAG3 and TIM3 immunohistochemistry on samples obtained before and after NACT. The cut-off threshold to consider a positive sample was set at 5%. RESULTS: In our cohort, TIM3 was the most prevalent co-regulator, with more than 75% of the samples being TIM3 positive. In comparison, only 22%, 28% and 17% of the samples were considered IDO, PDL1 and LAG3 positive. More than half of ovarian tumors expressed 2, 3 or even all 4 co-inhibitory molecules. However, biomarkers were not correlated with each other. NACT had a marked impact on immune co-regulator expression with over 70% of patients showing a change in biomarker status from negative to positive or vice versa. There was no significant difference in the pattern of co-regulator expression between platinum-sensitive and resistant patients. Co-expression of multiple inhibitory molecules did not appear to affect overall and progression-free survival. CONCLUSION: TIM3 is the most abundant co-inhibitory molecule in OC and may represent an attractive target. In addition, OC frequently co-expressed 2 or more markers supporting ICI combinatorial approaches. Finally, NACT significantly altered the expression of immunosuppressive molecules suggesting that the choice of ICI combinations should be adapted to the composition of the post-NACT immune TME.