Jean Claude Pairon

Adverse Effects of Industrial Multiwalled Carbon Nanotubes on Human Pulmonary Cells

The aim of this study was to evaluate adverse effects of multiwalled carbon nanotubes (MWCNT), produced for industrial purposes, on the human epithelial cell line A549. MWCNT were dispersed in dipalmitoyl lecithin (DPL), a component of pulmonary surfactant, and the effects of dispersion in DPL were compared to those in two other media: ethanol (EtOH) and phosphate-buffered saline (PBS). Effects of MWCNT were also compared to those of two asbestos fibers (chrysotile and crocidolite) and carbon black (CB) nanoparticles, not only in A549 cells but also in mesothelial cells (MeT5A human cell line), used as an asbestos-sensitive cell type. MWCNT formed agglomerates on top of both cell lines (surface area 15–35 μm2) that were significantly larger and more numerous in PBS than in EtOH and DPL. Whatever the dispersion media, incubation with 100 μg/ml MWCNT induced a similar decrease in metabolic activity without changing cell membrane permeability or apoptosis. Neither MWCNT cellular internalization nor oxidative stress was observed. In contrast, asbestos fibers penetrated into the cells, decreased metabolic activity but not cell membrane permeability, and increased apoptosis, without decreasing cell number. CB was internalized without any adverse effects. In conclusion, this study demonstrates that MWCNT produced for industrial purposes exert adverse effects without being internalized by human epithelial and mesothelial pulmonary cell lines.

Occupations and Industries in France at High Risk for Pleural Mesothelioma: A Population-Based Case-Control Study (1998-2002)

BACKGROUND Occupational exposure to asbestos, widely used in various industries for decades, is the most important risk factor for pleural mesothelioma. We report here the ranking of occupations and industries in France at high risk for this cancer among men and women. METHODS A population-based case-control study, conducted from 1998 to 2002, included 462 cases (80.3% men) and 897 controls. Data were collected in face-to-face interviews with a standardized questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each occupation and industry; subjects never employed in each category were the reference. RESULTS For men, risks were high for several occupations and industries. Besides the expected high risks for non-metallic mineral product makers and manufacturing asbestos products, occupations such as plumbers (OR = 5.57, 95% CI: 2.90-10.69), sheet-metal workers, welders, metal molders, coremakers, and cabinetmakers were also at high risk. Elevated risks were found in the industries of shipbuilding (OR = 9.13, 95% CI: 5.20-16.06) and construction, but also in the manufacturing of metal products, chemicals, and railroad and aircraft equipment. The results for women showed increased but not significant risks in several occupational activities. CONCLUSIONS This report provides new insight into the epidemiology of mesothelioma, confirming risks for occupational activities reported earlier and pointing out risks in activities never previously reported. It offers guidance to authorities for the compensation of asbestos victims and for prevention in at-risk activities still involving asbestos-containing products.

Lymphohistiocytoid variant of malignant mesothelioma of the pleura: a series of 22 cases.

The lymphohistiocytoid variant of diffuse malignant mesothelioma is rare with very few cases described in the literature. It is characterized by mesothelial cells with a histiocytelike appearance and an associated dense lymphoid infiltrate. We studied clinicopathologic features and immunohistochemical patterns of a series of 22 cases. The histiocytelike cells had a mesothelial immunophenotype: AE1/AE3 (100%), calretinin (100%), CK5/6 (46%), and EMA (52%). The prominent lymphoid component showed a cytotoxic T-cell immunophenotype. Prognosis was similar to that of a large series of epithelioid diffuse malignant mesotheliomas. Formely, it was classified within the sarcomatoid type. We suggest that it should be reclassified as an epithelioid variant because of its similar behavioural characteristics. There was no evidence of Epstein-Barr virus-related infection.

Attributable risk in men in two French case-control studies on mesothelioma and asbestos.

Pleural mesothelioma is a primary tumor of the pleura that is mainly due to asbestos exposure. To study the relationship between mesothelioma and occupational asbestos exposure in France, two case–control studies (A and B) were conducted. A substantial difference in the attributable risk in the population (ARp) was observed among men: 44.5% (95% CI: [32.6–56.4]) in study A and 83.2% (95% CI: [76.8–89.6]) in study B. As different exposure assessment expert methods were used, the main objective of this work was to re-estimate the ARp men in two case–control studies according to a common standardized exposure assessment by using a Job Exposure Matrix (JEM) and to assess the role of subjects’ selection. The initial observed ARp difference was maintained: 36.3% (95% CI: [24.3–50.3]) in study A and 69.7% (95% CI: [51.7–83.2]) in study B. Further investigations highlighted the potential selection bias introduced in both studies, especially among controls. The ARp could be underestimated in study A and overestimated in study B. After weighting subjects according to distribution of socio-economic status in the general population for controls and according to distribution of socio-economic status of cases registered by the French National Mesothelioma Surveillance Program, re-estimated ARp values were 52.4% in study A and 70.2% in study B. These results provide additional information to describe the relationship between pleural mesothelioma and occupational asbestos exposure, but also confirm the importance of subjects’ recruitment in case control studies, particularly control selection.

Initial characterization of human thymocyte sialidase activity: evidence that this enzymatic system is not altered during the course of T-cell maturation.

1. The sialidase activity of human thymocyte was examined by a fluorogenic assay. 2. These studies revealed that human thymocyte sialidase activity is essentially acid-active and membrane-bound since 59.6% and 33% of the total activity was recovered in the lysosome-enriched and microsomal fractions, respectively. 3. A weak activity was also detected in the cytosolic fraction. 4. However, the acidic optimum pH of this soluble sialidase was at variance with the general concept of mammalian soluble sialidases which are known to be optimally active at more neutral pH. 5. This acidic soluble sialidase seems to be a general characteristic of the human T-cell lineage since examination of mature circulating T-cells revealed that they contain a soluble sialidase activity similar to that observed in thymocytes. 6. Analysis of mature and immature thymocyte subpopulation obtained by differential PNA agglutination indicated that this enzymatic system was not altered during the course of thymic maturation. 7. These results suggest that unlike in T-cell activation where changes in the level of sialidase activity were shown to influence the extent of cell surface sialylation and thereby the cell physiology, this enzymatic system seems not to be involved in the fluctuation of cell surface sialic acid content observed during thymic maturation.

Perspectives in Biological Monitoring of Inhaled Nanosized Particles

Given the results of experimental studies, occupational or environmental exposures to manufactured nanoparticles or to unintentionally produced ultrafine particles may result in health effects or diseases in humans. In this review, we synthesize published data of experimental studies on the distribution of inhaled nanoparticles and the first case reports to discuss the potential usefulness of their biological monitoring for clinical purposes. Toxicokinetic studies suggest that nanoparticles may be absorbed predominantly by respiratory and oral routes with possible systemic translocation, leading to accumulation in the peripheral organs or excretion in feces or urine. Some methods used in these studies may be applied successfully in retrospective evaluation of exposure or in follow-up of occupational exposure in the workplace. Biological monitoring of nanoparticles should be based on imaging methods that are essential to confirm their presence and to characterize them in tissue associated with analytical quantitative methods. The first case reports reviewed emphasize the urgent need for the development of standardized procedures for the preparation and analysis of biological samples with a view to characterizing and quantifying nanoparticles.

The role of p53 in lung macrophages following exposure to a panel of manufactured nanomaterials

Manufactured nanomaterials (MNMs) have the potential to improve everyday life as they can be utilised in numerous medical applications and day-to-day consumer products. However, this increased use has led to concerns about the potential environmental and human health impacts. The protein p53 is a key transcription factor implicated in cellular defence and reparative responses to various stress factors. Additionally, p53 has been implicated in cellular responses following exposure to some MNMs. Here, the role of the MNM mediated p53 induction and activation and its downstream effects following exposure to five well-characterised materials [namely two types of TiO2, two carbon black (CB), and one single-walled carbon nanotube (SWCNT)] were investigated. MNM internalisation, cellular viability, p53 protein induction and activation, oxidative stress, inflammation and apoptosis were measured in murine cell line and primary pulmonary macrophage models. It was observed that p53 was implicated in the biological responses to MNMs, with oxidative stress associated with p53 activation (only following exposure to the SWCNT). We demonstrate that p53 acted as an antioxidant and anti-inflammatory in macrophage responses to SWCNT and CB NMs. However, p53 was neither involved in MNM-induced cellular toxicity, nor in the apoptosis induced by these MNMs. Moreover, the physicochemical characteristics of MNMs seemed to influence their biological effects-SWCNT the materials with the largest surface area and a fibrous shape were the most cytotoxic in this study and were capable of the induction and activation of p53.

New insights on diagnostic reproducibility of biphasic mesotheliomas: a multi-institutional evaluation by the international mesothelioma panel from the MESOPATH reference center

Introduction: The 2015 WHO classification of tumors categorized malignant mesothelioma into epithelioid, biphasic (BMM), and sarcomatoid (SMM) for prognostic relevance and treatment decisions. The survival of BMM is suspected to correlate with the amount of the sarcomatoid component. The criteria for a sarcomatoid component and the interobserver variability between pathologists for identifying this component are not well described. In ambiguous cases, a “transitional” (TMM) subtype has been proposed but was not accepted as a specific subtype in the 2015 WHO classification. The aims of this study were to evaluate the interobserver agreement in the diagnosis of BMM, to determine the nature and the significance of TMM subtype, and to relate the percentage of sarcomatoid component with survival. The value of staining for BRCA‐1‐associated protein (BAP1) and CDKN2A(p16) fluorescence in situ hybridization (FISH) were also assessed with respect to each of the tumoral components. Methods: The study was conducted by the International Mesothelioma Panel supported by the French National Cancer Institute, the network of rare cancer (EURACAN) and in collaboration with the International Association for the Study of Lung Cancer (IASLC). The patient cases include a random group of 42 surgical biopsy samples diagnosed as BMM with evaluation of SMM component by the French Panel of MESOPATH experts was selected from the total series of 971 BMM cases collected from 1998 to 2016. Fourteen international pathologists with expertise in mesothelioma reviewed digitally scanned slides (hematoxylin and eosin – stained and pan‐cytokeratin) without knowledge of prior diagnosis or outcome. Cases with at least 7 of 14 pathologists recognizing TMM features were selected as a TMM group. Demographic, clinical, histopathologic, treatment, and follow‐up data were retrieved from the MESOBANK database. BAP1 (clone C‐4) loss and CDKN2A(p16) homozygous deletion (HD) were assessed by immunohistochemistry (IHC) and FISH, respectively. Kappa statistics were applied for interobserver agreement and multivariate analysis with Cox regression adjusted for age and gender was performed for survival analysis. Results: The 14 panelists recorded a total of 544 diagnoses. The interobserver correlation was moderate (weighted Kappa = 0.45). Of the cases originally classified as BMM by MESOPATH, the reviewers agreed in 71% of cases (385 of 544 opinions), with cases classified as pure epithelioid in 17% (93 of 544), and pure sarcomatoid in 12% (66 of 544 opinions). Diagnosis of BMM was made on morphology or IHC alone in 23% of the cases and with additional assessment of IHC in 77% (402 of 544). The median overall survival (OS) of the 42 BMM cases was 8 months. The OS for BMM was significantly different from SMM and epithelioid malignant mesothelioma (p < 0.0001). In BMM, a sarcomatoid component of less than 80% correlated with a better survival (p = 0.02). There was a significant difference in survival between BMM with TMM showing a median survival at 6 months compared to 12 months for those without TMM (p < 0.0001). BAP1 loss was observed in 50% (21 of 42) of the total cases and in both components in 26%. We also compared the TMM group to that of more aggressive patterns of epithelioid subtypes of mesothelioma (solid and pleomorphic of our large MESOPATH cohort). The curve of transitional type was persistently close to the OS curve of the sarcomatoid component. The group of sarcomatoid, transitional, and pleomorphic mesothelioma were very close to each other. We then considered the contribution of BAP1 immunostaining and loss of CDKN2A(p16) by FISH. BAP1 loss was observed in 50% (21 of 41) of the total cases and in both component in 27% of the cases (11 of 41). There was no significant difference in BAP1 loss between the TMM and non‐TMM groups. HD CDKN2A(p16) was detected in 74% of the total cases with no significant difference between the TMM and non‐TMM groups. In multivariate analysis, TMM morphology was an indicator of poor prognosis with a hazard ratio = 3.2; 95% confidence interval: 1.6 – 8.0; and p = 0.003 even when compared to the presence of HD CDKN2A(p16) on sarcomatoid component (hazard ratio = 4.5; 95% confidence interval: 1.2 – 16.3, p = 0.02). Conclusions: The interobserver concordance among the international mesothelioma and French mesothelioma panel suggests clinical utility for an updated definition of biphasic mesothelioma that allows better stratification of patients into risk groups for treatment decisions, systemic anticancer therapy, or selection for surgery or palliation. We also have shown the usefulness of FISH detection of CDKN2A(p16) HD compared to BAP1 loss on the spindle cell component for the separation in ambiguous cases between benign florid stromal reaction from true sarcomatoid component of biphasic mesothelioma. Taken together our results further validate the concept of transitional pattern as a poor prognostic indicator.

Determinants of malignant pleural mesothelioma survival and burden of disease in France: a national cohort analysis

This study was undertaken to determine the healthcare burden of malignant pleural mesothelioma (MPM) in France and to analyze its associations with socioeconomic deprivation, population density, and management outcomes. A national hospital database was used to extract incident MPM patients in years 2011 and 2012. Cox models were used to analyze 1‐ and 2‐year survival according to sex, age, co‐morbidities, management, population‐density index, and social deprivation index. The analysis included 1,890 patients (76% men; age: 73.6 ± 10.0 years; 84% with significant co‐morbidities; 57% living in urban zones; 53% in highly underprivileged areas). Only 1% underwent curative surgical procedure; 65% received at least one chemotherapy cycle, 72% of them with at least one pemetrexed and/or bevacizumab administration. One‐ and 2‐year survival rates were 64% and 48%, respectively. Median survival was 14.9 (95% CI: 13.7–15.7) months. The mean cost per patient was 27,624 ± 17,263 euros (31% representing pemetrexed and bevacizumab costs). Multivariate analyses retained men, age >70 years, chronic renal failure, chronic respiratory failure, and never receiving pemetrexed as factors of poor prognosis. After adjusting the analysis to age, sex, and co‐morbidities, living in rural/semi‐rural area was associated with better 2‐year survival (HR: 0.83 [95% CI: 0.73–0.94]; P < 0.01); social deprivation index was not significantly associated with survival. With approximately 1,000 new cases per year in France, MPMs represents a significant national health care burden. Co‐morbidities, sex, age, and living place appear to be significant factors of prognosis.

Prevalence of occupational exposure to asbestos and crystalline silica according to phenotypes of lung cancer from the CaProMat study: A case‐only study

BACKGROUND The objective of the study was to compare the prevalence of occupational exposure to asbestos and crystalline silica according to histological types of lung cancer and age at diagnosis. METHODS CaProMat study is a pooled case-only study conducted between 1996 and 2011. The current study consisted of 6521 lung cancer cases. Occupational exposure to asbestos and crystalline silica was assessed by two Job-Exposure Matrices. A weighted prevalence of exposure was derived and compared according to histological types and age at diagnosis. RESULTS There was no difference of weighted prevalence of exposure to asbestos and crystalline silica according to histological types of lung cancer. There was a statistically significant difference of weighted prevalence of exposure to asbestos and crystalline silica according to age at diagnosis. CONCLUSIONS Due to the limited clinical importance of the difference, neither the histological type, nor the age at diagnosis can be used as an indicator for the occupational exposure to asbestos or crystalline silica.