Les composés perfluorés (PFC) de formule chimique générale CF3-(CF2)n-SO3- ( sulfonates) ou CF3-(CF2)n-1-CO2- (acides) sont des polluants organiques émergents, dont la persistance, la bioaccumulation et la toxicité sont maintenant considérées préoccupantes au plan sanitaire et environnemental. L'objectif de notre recherche a été de mettre en évidence les effets cancérogènes in vitro et le mécanisme d'action impliqué lors de l'exposition pendant 7 jours de cellules embryonnaires de hamster Syrien (SHE) aux principaux représentants perfluorés, le sulfonate de perfluorooctane (PFOS), le perfluorooctanoate (PFOA), et à leur substitut, le sulfonate de perfluorobutane (PFBS). Le test de transformation cellulaire dans sa version standard ou selon un protocole de type initiation-promotion a permis de détecter les substances cancérogènes de profil initiateur ou promoteur de tumeur. La génotoxicité des PFCs a été explorée par le test Comet en conditions alcalines. PFOS a présenté un profil cancérogène non génotoxique de type initiateur aux concentrations de 0,37 et 3,7 µM (p<=0,01), coïncidant avec les concentrations sériques des travailleurs exposés au PFOS. L'activation des gènes PPARs a été observée après 7 jours d'exposition au PFOS, avec une induction plus importante et plus précoce (dès 24 heures d'exposition) du gène ppar-bêta/gamma aux concentrations transformantes (p<=0,05). PFOA appliqué seul n'induit pas la transformation néoplasique des cellules SHE. Par contre, il induit la transformation des cellules présensibilisées par un initiateur. Il agit selon un profil cancérogène non génotoxique de type promoteur de tumeur aux concentrations de 3,7 x 10-4 à 37 µM. Ces concentrations coïncident avec les concentrations sériques mesurées dans les populations professionnellement et non professionnellement exposées. PFBS ne s'est révélé ni initiateur, ni promoteur de tumeur. La mise en cause de ces PFCs dans l'augmentation des cancers de la vessie (pour le PFOS) et celui de la prostate (pour le PFOA) chez les travailleurs exposés ne peut être exclue / Perfluorinated compounds (PFCs) is a collective name for fluorinated surfactants and polymers with the general structure CF3-(CF2)n-SO3- (sulfonates) or CF3-(CF2)n-1-CO2- .(acids). This group is characterized by a high persistence, bioaccumulation and long term toxicity which are rising environmental and public health concerns. In the present work, we analyzed the in vitro carcinogenic potential of the two major PFCs, perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA), and their substitute, perfluorobutane sulfonate (PFBS). Cell transformation assays were carried out on Syrian hamster embryo (SHE) cells in a 7 day-treatment using the standard and the initiation-promotion protocols. Genotoxicity was tested using the comet assay. PFOS was not genotoxic on SHE cells, but it induced cell transformation at non cytotoxic concentrations 0,37 and 3,7 µM (p<=0,01). These concentrations coincided with serum PFOS concentrations measured in occupationally exposed workers. An increased expression of PPARs was registered after 7 days. The ppar-beta/gamma mRNA appeared to increase rapidly (24 hours after PFOS treatment) at concentrations closely related to cell transformation (p<=0,05). PFOA was inactive alone, but induced cell transformation of SHE cells pre-initiated with benzo(a)pyrene (BaP). Therefore PFOA was shown to act as a tumor promoter and a non genotoxic carcinogen at a large range of concentrations (3,7 x 10-4 à 37 µM). This range of concentrations covered seric concentrations in non-occupationally exposed and occupationally exposed populations. PFBS was negative alone and on BaP-pretreated SHE cells. For this reason, its use as a substitute for PFOS appears to be justified. To conclude, the cell transforming potenty of PFOS and PFOA denotes in vitro carcinogenic potential. Consequently, the hypothesis of their implication in human cancer recorded in occupationally exposed populations cannot be ruled out

Background In some cross-sectional epidemiologic studies the shape of the association between serum concentrations of perfluoroalkyl acids (PFAAs) and lipids suggests departures from linearity. Objectives We used statistical approaches allowing for non-linearity to determine associations of prenatal exposures of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) with lipid concentrations. Methods PFAAs were measured in serum from pregnant women collected in 1991–1992 at enrollment in the Avon Longitudinal Study of Parents and Children and lipids in serum from their daughters at ages 7 (n = 111) and 15 (n = 88). The associations of PFAAs with lipids were first explored by cubic splines, followed by piecewise linear regressions by tertiles to obtain regression coefficients (β) and their 95% confidence limits (95% CL) (in mg/dL per 1 ng/mL). Results At age 7, total cholesterol was positively associated with prenatal PFOA concentrations in the lower tertile (β = 15.01; 95% CL = 2.34, 27.69) but not with PFOA concentrations in the middle (β = − 3.63; 95% CL = − 17.43, 10.16) and upper (β = − 1.58; 95% CL = − 4.58, 1.42) tertiles. At age 15, a similar pattern was noted as well. Positive associations between LDL-C and prenatal PFOA concentration in the lower tertile were observed in daughters at ages 7 (β = 14.91; 95% CL = 3.53, 28.12) and 15 (β = 13.93; 95% CL = 0.60, 27.26). LDL-C was not associated with PFOA concentrations in the middle or upper tertile at any age. Neither HDL-C nor triglycerides was associated with prenatal PFOA exposure. Non-linear patterns of association of total cholesterol and LDL-C with prenatal PFOS were less consistently noted. Conclusion Exposure to low levels of PFOA during prenatal development may alter lipid metabolism later in life. Given the small sample size further replication of the association in large independent cohorts is important.

Background: Fatty acids (FA) have a role on energy storage and membrane formation. FA consists of an aliphatic chain with varying number of carbon and a carboxylic functional group. Perfluorooctanoic acid (PFOA) exhibits a similar structure to that of the FA. Given their structural resemblance, we hypothesized that alterations in FA metabolism could arise from competition with PFOA for endogenous FA binding sites in transport and with FA binding proteins. Objectives: Explore associations of serum concentrations of perfluorooctanoic acid (PFOA) with serum concentrations of linoleic (LA), eicosapentanoic (EPA), and docosapentanoic (DHA) acid in adults. Methods: We analyzed data from 1,829, 20-80 years old participants in the 2003–2004 National Health and Nutrition Examination Survey (NHANES). Linear regression models were used to estimate adjusted predicted means of the FA (in µmol/L) for quartiles of PFOA (in ng/mL) and explore linear trends. Results: Increasing concentrations of PFOA were not associated with adjusted predicted means of serum LA (Q1 3534, Q2 3445, Q3 3778, Q4 3399) (p trends=0.6460). Increasing concentrations of PFOA, however, were associated with increasing trends in adjusted predicted means of serum EPA (Q1 49.8, Q2 51.5, Q3 60.9, Q4 55.7).

Perfluoroalkyl compounds (PFCs) are a group of chemical surfactants most notably used in non-stick and stain-resistance applications. Due to their wide-spread use and inherent resistance to degradation, several PFCs have become persistent environmental contaminants. Despite the high concentrations of PFCs reported in wild birds and their eggs, very little is known about the toxicological effects they have on avian species. This thesis investigates the developmental toxicity of PFCs in an avian model species: the domestic chicken (Gallus gallus domesticus). Egg injection experiments were performed to assess the in ovo toxicity of perfluorooctane sulfonate (technical grade, T-PFOS), perfluorooctanoic acid (PFOA), perfluorodecane sulfonate (PFDS) and perfluoroundecanoic acid (PFUdA). Real-time RT-PCR was then used to measure the transcription of candidate biomarker genes in the liver tissue of day 20 embryos. Candidate genes were selected based on their responsiveness to PFC exposure in previously conducted in vitro screening assays. In ovo exposure to PFOS resulted in a dose-dependent decrease in embryo pipping success (a measure of hatching success) with an LD50 of 93 μg/g (3.54 μg/g-672,910 μg/g, 95% confidence interval), however the expression of peroxisome proliferator-activated receptor alpha (PPARα)-regulated genes was not affected in liver tissue as hypothesized. PFOA, PFDS and PFUdA had no effect on the pipping success of chicken embryos. The expression of cytochrome P450 1A4 (CYP1A4) and liver fatty acid binding protein (L-FABP) mRNA increased in embryo liver tissue following in ovo exposure to PFUdA but was only statistically significant at 10 μg/g, which is several orders of magnitude higher than concentrations reported in wild bird eggs. The isomer-specific accumulation of PFOS in chicken embryo livers was also investigated using an in-port derivatization gas-chromatography/mass spectrometry (GC-MS) method. Prior to incubation, chicken eggs were injected with T-PFOS, composed of 63% linear isomer (L-PFOS) and 37.3% branched isomers. The isomer profiles in day-20 embryo liver tissue showed up to 20% enrichment in the proportion of L-PFOS, compared to T-PFOS, with a corresponding decrease in the proportion of branched isomers. This enrichment was inversely proportional to dose. Finally, the transcriptional profiles of cultured chicken embryonic hepatocytes (CEH) exposed to either T-PFOS or L-PFOS were compared using Agilent 4x44k Chicken (V2) Gene Expression microarrays. At equal concentrations (10 μM), T-PFOS altered the expression of significantly more genes (340 genes, >1.5 fold change, false discovery rate adjusted p<0.05) compared to L-PFOS (130 genes). Functional analysis showed that L-PFOS and T-PFOS affected genes involved in lipid metabolism, cellular growth and proliferation, and cell-cell signaling. Pathway and interactome analysis suggested that gene expression may be affected through RXR, oxidative stress response, TP53 signaling, MYC signaling, Wnt/β-catenin signaling and PPARγ and SREBP receptors. In all functional categories and pathways examined, T-PFOS had a more pronounced disruptive effect on transctional regulation than L-PFOS. In summary, egg injection experiments showed that T-PFOS (but not linear PFOA, PFDS or PFUdA) may affect the hatching success of the chicken at environmentally relevant concentrations. It was also demonstrated that the accumulation of PFOS in embryonic liver is isomer specific, and leads to an enrichment of L-PFOS. The increased transcriptional disruption caused by T-PFOS in cultured hepatocytes over L-PFOS suggests that the branched isomers may be largely responsible for the toxicological effects of PFOS. Combined, the results from this thesis demonstrate the importance of considering PFOS isomer burdens during risk assessment. In addition, gene expression analysis identified several candidate mechanisms for PFOS toxicity.

Perfluoroalkyl compounds (PFCs) are a group of chemical surfactants most notably used in non-stick and stain-resistance applications. Due to their wide-spread use and inherent resistance to degradation, several PFCs have become persistent environmental contaminants. Despite the high concentrations of PFCs reported in wild birds and their eggs, very little is known about the toxicological effects they have on avian species. This thesis investigates the developmental toxicity of PFCs in an avian model species: the domestic chicken (Gallus gallus domesticus). Egg injection experiments were performed to assess the in ovo toxicity of perfluorooctane sulfonate (technical grade, T-PFOS), perfluorooctanoic acid (PFOA), perfluorodecane sulfonate (PFDS) and perfluoroundecanoic acid (PFUdA). Real-time RT-PCR was then used to measure the transcription of candidate biomarker genes in the liver tissue of day 20 embryos. Candidate genes were selected based on their responsiveness to PFC exposure in previously conducted in vitro screening assays. In ovo exposure to PFOS resulted in a dose-dependent decrease in embryo pipping success (a measure of hatching success) with an LD50 of 93 μg/g (3.54 μg/g-672,910 μg/g, 95% confidence interval), however the expression of peroxisome proliferator-activated receptor alpha (PPARα)-regulated genes was not affected in liver tissue as hypothesized. PFOA, PFDS and PFUdA had no effect on the pipping success of chicken embryos. The expression of cytochrome P450 1A4 (CYP1A4) and liver fatty acid binding protein (L-FABP) mRNA increased in embryo liver tissue following in ovo exposure to PFUdA but was only statistically significant at 10 μg/g, which is several orders of magnitude higher than concentrations reported in wild bird eggs. The isomer-specific accumulation of PFOS in chicken embryo livers was also investigated using an in-port derivatization gas-chromatography/mass spectrometry (GC-MS) method. Prior to incubation, chicken eggs were injected with T-PFOS, composed of 63% linear isomer (L-PFOS) and 37.3% branched isomers. The isomer profiles in day-20 embryo liver tissue showed up to 20% enrichment in the proportion of L-PFOS, compared to T-PFOS, with a corresponding decrease in the proportion of branched isomers. This enrichment was inversely proportional to dose. Finally, the transcriptional profiles of cultured chicken embryonic hepatocytes (CEH) exposed to either T-PFOS or L-PFOS were compared using Agilent 4x44k Chicken (V2) Gene Expression microarrays. At equal concentrations (10 μM), T-PFOS altered the expression of significantly more genes (340 genes, >1.5 fold change, false discovery rate adjusted p<0.05) compared to L-PFOS (130 genes). Functional analysis showed that L-PFOS and T-PFOS affected genes involved in lipid metabolism, cellular growth and proliferation, and cell-cell signaling. Pathway and interactome analysis suggested that gene expression may be affected through RXR, oxidative stress response, TP53 signaling, MYC signaling, Wnt/β-catenin signaling and PPARγ and SREBP receptors. In all functional categories and pathways examined, T-PFOS had a more pronounced disruptive effect on transctional regulation than L-PFOS. In summary, egg injection experiments showed that T-PFOS (but not linear PFOA, PFDS or PFUdA) may affect the hatching success of the chicken at environmentally relevant concentrations. It was also demonstrated that the accumulation of PFOS in embryonic liver is isomer specific, and leads to an enrichment of L-PFOS. The increased transcriptional disruption caused by T-PFOS in cultured hepatocytes over L-PFOS suggests that the branched isomers may be largely responsible for the toxicological effects of PFOS. Combined, the results from this thesis demonstrate the importance of considering PFOS isomer burdens during risk assessment. In addition, gene expression analysis identified several candidate mechanisms for PFOS toxicity.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第18971号 / 工博第4013号 / 新制||工||1618 / 31922 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 米田 稔, 教授 田中 宏明, 准教授 藤川 陽子 / 学位規則第4条第1項該当

Perfluoroalkyl compounds (PFCs) are a group of chemical surfactants most notably used in non-stick and stain-resistance applications. Due to their wide-spread use and inherent resistance to degradation, several PFCs have become persistent environmental contaminants. Despite the high concentrations of PFCs reported in wild birds and their eggs, very little is known about the toxicological effects they have on avian species. This thesis investigates the developmental toxicity of PFCs in an avian model species: the domestic chicken (Gallus gallus domesticus). Egg injection experiments were performed to assess the in ovo toxicity of perfluorooctane sulfonate (technical grade, T-PFOS), perfluorooctanoic acid (PFOA), perfluorodecane sulfonate (PFDS) and perfluoroundecanoic acid (PFUdA). Real-time RT-PCR was then used to measure the transcription of candidate biomarker genes in the liver tissue of day 20 embryos. Candidate genes were selected based on their responsiveness to PFC exposure in previously conducted in vitro screening assays. In ovo exposure to PFOS resulted in a dose-dependent decrease in embryo pipping success (a measure of hatching success) with an LD50 of 93 μg/g (3.54 μg/g-672,910 μg/g, 95% confidence interval), however the expression of peroxisome proliferator-activated receptor alpha (PPARα)-regulated genes was not affected in liver tissue as hypothesized. PFOA, PFDS and PFUdA had no effect on the pipping success of chicken embryos. The expression of cytochrome P450 1A4 (CYP1A4) and liver fatty acid binding protein (L-FABP) mRNA increased in embryo liver tissue following in ovo exposure to PFUdA but was only statistically significant at 10 μg/g, which is several orders of magnitude higher than concentrations reported in wild bird eggs. The isomer-specific accumulation of PFOS in chicken embryo livers was also investigated using an in-port derivatization gas-chromatography/mass spectrometry (GC-MS) method. Prior to incubation, chicken eggs were injected with T-PFOS, composed of 63% linear isomer (L-PFOS) and 37.3% branched isomers. The isomer profiles in day-20 embryo liver tissue showed up to 20% enrichment in the proportion of L-PFOS, compared to T-PFOS, with a corresponding decrease in the proportion of branched isomers. This enrichment was inversely proportional to dose. Finally, the transcriptional profiles of cultured chicken embryonic hepatocytes (CEH) exposed to either T-PFOS or L-PFOS were compared using Agilent 4x44k Chicken (V2) Gene Expression microarrays. At equal concentrations (10 μM), T-PFOS altered the expression of significantly more genes (340 genes, >1.5 fold change, false discovery rate adjusted p<0.05) compared to L-PFOS (130 genes). Functional analysis showed that L-PFOS and T-PFOS affected genes involved in lipid metabolism, cellular growth and proliferation, and cell-cell signaling. Pathway and interactome analysis suggested that gene expression may be affected through RXR, oxidative stress response, TP53 signaling, MYC signaling, Wnt/β-catenin signaling and PPARγ and SREBP receptors. In all functional categories and pathways examined, T-PFOS had a more pronounced disruptive effect on transctional regulation than L-PFOS. In summary, egg injection experiments showed that T-PFOS (but not linear PFOA, PFDS or PFUdA) may affect the hatching success of the chicken at environmentally relevant concentrations. It was also demonstrated that the accumulation of PFOS in embryonic liver is isomer specific, and leads to an enrichment of L-PFOS. The increased transcriptional disruption caused by T-PFOS in cultured hepatocytes over L-PFOS suggests that the branched isomers may be largely responsible for the toxicological effects of PFOS. Combined, the results from this thesis demonstrate the importance of considering PFOS isomer burdens during risk assessment. In addition, gene expression analysis identified several candidate mechanisms for PFOS toxicity.

Perfluoroalkyl compounds (PFCs) are a group of chemical surfactants most notably used in non-stick and stain-resistance applications. Due to their wide-spread use and inherent resistance to degradation, several PFCs have become persistent environmental contaminants. Despite the high concentrations of PFCs reported in wild birds and their eggs, very little is known about the toxicological effects they have on avian species. This thesis investigates the developmental toxicity of PFCs in an avian model species: the domestic chicken (Gallus gallus domesticus). Egg injection experiments were performed to assess the in ovo toxicity of perfluorooctane sulfonate (technical grade, T-PFOS), perfluorooctanoic acid (PFOA), perfluorodecane sulfonate (PFDS) and perfluoroundecanoic acid (PFUdA). Real-time RT-PCR was then used to measure the transcription of candidate biomarker genes in the liver tissue of day 20 embryos. Candidate genes were selected based on their responsiveness to PFC exposure in previously conducted in vitro screening assays. In ovo exposure to PFOS resulted in a dose-dependent decrease in embryo pipping success (a measure of hatching success) with an LD50 of 93 μg/g (3.54 μg/g-672,910 μg/g, 95% confidence interval), however the expression of peroxisome proliferator-activated receptor alpha (PPARα)-regulated genes was not affected in liver tissue as hypothesized. PFOA, PFDS and PFUdA had no effect on the pipping success of chicken embryos. The expression of cytochrome P450 1A4 (CYP1A4) and liver fatty acid binding protein (L-FABP) mRNA increased in embryo liver tissue following in ovo exposure to PFUdA but was only statistically significant at 10 μg/g, which is several orders of magnitude higher than concentrations reported in wild bird eggs. The isomer-specific accumulation of PFOS in chicken embryo livers was also investigated using an in-port derivatization gas-chromatography/mass spectrometry (GC-MS) method. Prior to incubation, chicken eggs were injected with T-PFOS, composed of 63% linear isomer (L-PFOS) and 37.3% branched isomers. The isomer profiles in day-20 embryo liver tissue showed up to 20% enrichment in the proportion of L-PFOS, compared to T-PFOS, with a corresponding decrease in the proportion of branched isomers. This enrichment was inversely proportional to dose. Finally, the transcriptional profiles of cultured chicken embryonic hepatocytes (CEH) exposed to either T-PFOS or L-PFOS were compared using Agilent 4x44k Chicken (V2) Gene Expression microarrays. At equal concentrations (10 μM), T-PFOS altered the expression of significantly more genes (340 genes, >1.5 fold change, false discovery rate adjusted p<0.05) compared to L-PFOS (130 genes). Functional analysis showed that L-PFOS and T-PFOS affected genes involved in lipid metabolism, cellular growth and proliferation, and cell-cell signaling. Pathway and interactome analysis suggested that gene expression may be affected through RXR, oxidative stress response, TP53 signaling, MYC signaling, Wnt/β-catenin signaling and PPARγ and SREBP receptors. In all functional categories and pathways examined, T-PFOS had a more pronounced disruptive effect on transctional regulation than L-PFOS. In summary, egg injection experiments showed that T-PFOS (but not linear PFOA, PFDS or PFUdA) may affect the hatching success of the chicken at environmentally relevant concentrations. It was also demonstrated that the accumulation of PFOS in embryonic liver is isomer specific, and leads to an enrichment of L-PFOS. The increased transcriptional disruption caused by T-PFOS in cultured hepatocytes over L-PFOS suggests that the branched isomers may be largely responsible for the toxicological effects of PFOS. Combined, the results from this thesis demonstrate the importance of considering PFOS isomer burdens during risk assessment. In addition, gene expression analysis identified several candidate mechanisms for PFOS toxicity.

No description available.

Diploma work focuses on the determination of selected representatives of perfluoroalkyl substances in complex matrices, particularly, in sewage sludge and feed. In case of sewage sludge, samples were extracted into methanol and three extractions techniques were compared: accelerated Soxhlet, pressurized liquid extraction and Powley method. Powley method showed sufficient efficiency, the lowest matrix effect and minimal background. Perfluorooctane sulfonate was present in all tested samples of sewage sludge (0.74–38.02 ng.g-1). Other detected compounds were perfluorodecanoic acid and perfluorooctanoic acid. Three extraction techniques were tested on feed samples (QuEChERS, fast methanol extraction and Powley method into acetonitrile). Powley method provided the cleanest extracts and showed simultaneously the highest recovery of native perfluoroalkyl substances and the lowest matrix effects. Perfluorooctane sulfonate and perfluorooctanoic acid were rarely present in samples of complete and supplemental feeds, while other perfluoroalkyl substances were found at levels below limit of quantification or they were not detected at all. Perfluorooctane sulfonate (0.100–2.768 ng.g-1), perfluoroundecanoic acid and perfluorotridecanoic acid were determined in all fish meal samples.