10 research outputs found
Analysis of Thyroid Hormones in Serum of Baikal Seals and Humans by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) and Immunoassay Methods: Application of the LC-MS/MS Method to Wildlife Tissues
Thyroid hormones (THs) are essential for the regulation of growth and development in both humans and wildlife. Until recently, TH concentrations in the tissues of animals have been examined by immunoassay (IA) methods. IA methods are sensitive, but for TH analysis, they are compromised by a lack of adequate specificity. In this study, we determined the concentrations of six THs, l-thyroxine (T<sub>4</sub>), 3,3′,5-triiodo-l-thyronine (T<sub>3</sub>), 3,3′,5′-triiodo-l-thyronine (rT<sub>3</sub>), 3,5-diiodo-l-thyronine (3,5-T<sub>2</sub>), 3,3′-diiodo-l-thyronine (3,3′-T<sub>2</sub>), and 3-iodo-l-thyronine (3-T<sub>1</sub>), in the serum of humans (<i>n</i> = 79) and wild Baikal seals (<i>n</i> = 37), by isotope ([<sup>13</sup>C<sub>6</sub>]-T<sub>4</sub>)-dilution liquid chromatography (LC)-tandem mass spectrometry (MS/MS), and compared the TH levels with those measured by an electrochemiluminescent immunoassay (ECLIA) method. T<sub>3</sub> and T<sub>4</sub> were detected in all serum samples of both humans and Baikal seals, whereas T<sub>1</sub>, 3,3′-T<sub>2</sub>, and 3,5-T<sub>2</sub> were below the limit of detection (LOD). rT<sub>3</sub> was detected in Baikal seal sera at concentrations higher than T<sub>3</sub> in 28 seal samples, indicating an anomaly in deiodinase activity in Baikal seals. In humans, regression analyses of TH concentrations, measured by ECLIA and LC-MS/MS methods, showed significant correlations for T<sub>4</sub> (<i>r</i> = 0.852) and T<sub>3</sub> (<i>r</i> = 0.676; after removal of a serum sample with abnormal T<sub>3</sub> levels). In Baikal seals, a low correlation coefficient (<i>r</i> = 0.466) for T<sub>4</sub> levels and no correlation for T<sub>3</sub> levels (<i>p</i> = 0.093) were found between ECLIA and LC-MS/MS methods. These results suggest that interference by a nonspecific reaction against anti-T<sub>3</sub> and anti-T<sub>4</sub> antibodies used in the ECLIA can contribute to inaccuracies in TH measurement in Baikal seals. When the relationship between concentrations of THs in sera and dioxin-like toxic equivalents in blubber samples of Baikal seals (<i>n</i> = 19) was examined, a significantly negative correlation was found for serum T<sub>4</sub> levels measured by the LC-MS/MS method, but not for those measured by ECLIA. Thus, our results indicate that the LC-MS/MS method is more reliable and accurate for the elucidation of alteration in circulating TH levels in wildlife, as caused by environmental and physiological factors
Occurrence of Natural Mixed Halogenated Dibenzo‑<i>p</i>‑Dioxins: Specific Distribution and Profiles in Mussels from Seto Inland Sea, Japan
In addition to unintentional formation
of polychlorinated (PCDD/Fs),
polybrominated (PBDD/Fs), and mixed halogenated (PXDD/Fs) dibenzo-<i>p</i>-dioxins/dibenzofurans during industrial activities, recent
studies have shown that several PBDD and PXDD congeners can be produced
by marine algal species from the coastal environment. However, multiple
exposure status of anthropogenic and naturally derived dioxins in
marine organisms remains unclear. The present study examined the occurrence,
geographical distribution, and potential sources of PCDD/Fs, PBDD/Fs,
and PXDD/Fs using mussels and brown algae collected in 2012 from Seto
Inland Sea, Japan. The results showed the widespread occurrence of
not only PCDD/Fs but also PBDDs and PXDDs in Seto Inland Sea. The
geographical distribution pattern of PBDDs was similar to that of
PXDDs, which were obviously different from that of PCDDs and PCDFs,
and a significant positive correlation was observed between the levels
of their predominant congeners, i.e., 1,3,7-/1,3,8-TrBDDs and DiBMoCDDs.
Interestingly, potential precursors of 1,3,7-/1,3,8-TrBDDs and DiBMoCDDs,
hydroxylated tetrabrominated diphenyl ethers (6-HO-BDE-47 and 2′-HO-BDE-68)
and their mixed halogenated analogue (HO-TrBMoCDE), were also identified
in the mussel and brown alga samples collected at the same site, by
comprehensive two-dimensional gas chromatography with time-of-flight
mass spectrometry (GC × GC–ToFMS) analyses. It is noteworthy
that residue levels of 1,3,7-/1,3,8-TrBDDs and DiBMoCDDs in the mussel
were 30 times higher than those in the brown alga, suggesting the
bioaccumulation of these natural dioxins
Species- and Tissue-Specific Profiles of Polybrominated Diphenyl Ethers and Their Hydroxylated and Methoxylated Derivatives in Cats and Dogs
The
adverse effects of elevated polybrominated diphenyl ether (PBDE)
levels, reported in the blood of domestic dogs and cats, are considered
to be of great concern. However, the tissue distribution of PBDEs
and their derivatives in these animals is poorly understood. This
study determined the concentrations and profiles of PBDEs, hydroxylated
PBDEs (OH-PBDEs), methoxylated PBDEs (MeO-PBDEs), and 2,4,6-tribromophenol
(2,4,6-tri-BPh) in the blood, livers, bile, and brains of dogs and
cats in Japan. Higher tissue concentrations of PBDEs were found in
cats, with the dominant congener being BDE209. BDE207 was also predominant
in cat tissues, indicating that BDE207 was formed via BDE209 debromination.
BDE47 was the dominant congener in dog bile, implying a species-specific
excretory capacity of the liver. OH-PBDE and MeO-PBDE concentrations
were several orders of magnitude higher in cat tissues, with the dominant
congener being 6OH-BDE47, possibly owing to their intake of naturally
occurring MeO-PBDEs in food, MeO-PBDE demethylation in the liver,
and lack of UDP-glucuronosyltransferase, UGT1A6. Relatively high concentrations
of BDE209, BDE207, 6OH-BDE47, 2′MeO-BDE68, and 2,4,6-tri-BPh
were found in cat brains, suggesting a passage through the blood–brain
barrier. Thus, cats in Japan might be at a high risk from PBDEs and
their derivatives, particularly BDE209 and 6OH-BDE47
Uptake and Tissue Distribution of Pharmaceuticals and Personal Care Products in Wild Fish from Treated-Wastewater-Impacted Streams
A fish
plasma model (FPM) has been proposed as a screening technique
to prioritize potential hazardous pharmaceuticals to wild fish. However,
this approach does not account for inter- or intraspecies variability
of pharmacokinetic and pharmacodynamic parameters. The present study
elucidated the uptake potency (from ambient water), tissue distribution,
and biological risk of 20 pharmaceutical and personal care product
(PPCP) residues in wild cyprinoid fish inhabiting treated-wastewater-impacted
streams. In order to clarify the uncertainty of the FPM for PPCPs,
we compared the plasma bioaccumulation factor in the field (BAF<sub>plasma</sub> = measured fish plasma/ambient water concentration ratio)
with the predicted plasma bioconcentration factor (BCF<sub>plasma</sub> = fish plasma predicted by use of theoretical partition coefficients/ambient
water concentration ratio) in the actual environment. As a result,
the measured maximum BAF<sub>plasma</sub> of inflammatory agents was
up to 17 times higher than theoretical BCF<sub>plasma</sub> values,
leading to possible underestimation of toxicological risk on wild
fish. When the tissue–blood partition coefficients (tissue/blood
concentration ratios) of PPCPs were estimated, higher transportability
into tissues, especially the brain, was found for psychotropic agents,
but brain/plasma ratios widely varied among individual fish (up to
28-fold). In the present study, we provide a valuable data set on
the intraspecies variability of PPCP pharmacokinetics, and our results
emphasize the importance of determining PPCP concentrations in possible
target organs as well as in the blood to assess the risk of PPCPs
on wild fish
Anthropogenic and Naturally Produced Brominated Phenols in Pet Blood and Pet Food in Japan
Present study determined concentrations
and residue patterns of
bromophenols (BPhs) in whole blood samples of pet cats and pet dogs
collected from veterinary hospitals in Japan. BPhs concentrations
were higher in cat blood than in dog blood, with statistically insignificant
differences (<i>p</i> = 0.07). Among the congeners, 2,4,6-tribromophenol
(TBPh) constituted the majority of BPhs (>90%) detected in both
species.
Analysis of commercial pet food to estimate exposure routes showed
that the most abundant congener in all pet food samples was 2,4,6-TBPh,
accounting for >99% of total BPhs. This profile is quite similar
to
the blood samples of the pets, suggesting that diet might be an important
exposure route for BPhs in pets. After incubation in polybrominated
diphenyl ether (PBDE) mixtures (BDE-47, BDE-99 and BDE-209), 2,4,5-TBPh
was found in dog liver microsomes but not in cat liver microsomes,
implying species-specific metabolic capacities for PBDEs. Formation
of 2,4,5-TBPh occurred by hydroxylation at the 1′ carbon atom
of the ether bond of BDE-99 is similar to human study reported previously.
Hydroxylated PBDEs were not detected in cats or dogs; therefore, diphenyl
ether bond cleavage of PBDEs can also be an important metabolic pathway
for BPhs formation in cats and dogs
Toxicological Assessment of Polychlorinated Biphenyls and Their Metabolites in the Liver of Baikal Seal (<i>Pusa sibirica</i>)
We
have previously reported that high accumulation of dioxins and
related compounds induced cytochrome P450 (CYP 1s) isozymes in the
liver of wild Baikal seals, implying the enhanced hydroxylation of
polychlorinated biphenyls (PCBs). The present study attempted to elucidate
the residue concentrations and patterns of PCBs and hydroxylated PCBs
(OH-PCBs) in the livers of Baikal seals. The hepatic residue concentrations
were used to assess the potential effects of PCBs and OH-PCBs in combination
with the analyses of serum thyroid hormones, hepatic mRNA levels,
and biochemical markers. The hepatic expression levels of CYP1 genes
were positively correlated with the concentration of each OH-PCB congener.
This suggests chronic induction of these CYP1 isozymes by exposure
to PCBs and hydroxylation of PCBs induced by CYP 1s. Hepatic mRNA
expression monitoring using a custom microarray showed that chronic
exposure to PCBs and their metabolites alters the gene expression
levels related to oxidative stress, iron ion homeostasis, and inflammatory
responses. In addition, the concentrations of OH-PCBs were negatively
correlated with l-thyroxine (T<sub>4</sub>) levels and the
ratios of 3,3′,5-triiodo-l-thyronine (T<sub>3</sub>)/reverse 3,3′,5′-triiodo-l-thyroninee (rT<sub>3</sub>). These observations imply that Baikal seals contaminated
with high levels of OH-PCBs may undergo the disruption of mechanisms
related to the formation (or metabolism) of T<sub>3</sub> and T<sub>4</sub> in the liver
Toxic Identification and Evaluation of Androgen Receptor Antagonistic Activities in Acid-Treated Liver Extracts of High-Trophic Level Wild Animals from Japan
Sulfuric
acid-treated liver extracts of representative high-trophic
level Japanese animals were analyzed by toxic identification and evaluation
(TIE) with chemically activated luciferase expression (CALUX) and
chemical analysis to elucidate androgen receptor (AR) antagonistic
activities and potential contributions of organochlorine pesticides
(OCPs) and polychlorinated biphenyls (PCBs). The activities were detected
in striped dolphins (<i>n</i> = 5), Stejneger’s beaked
whales (<i>n</i> = 6), golden eagle (<i>n</i> =
1), and Steller’s sea eagle (<i>n</i> = 1) with CALUX-flutamide
equivalents (FluEQs) as follow: 38 (20–52), 47 (21–96),
5.0, and 80 μg FluEQ/g-lipid, respectively. The AR antagonism
was detected in limited number of specimens at lower levels for finless
porpoise, raccoon dog, and common cormorant. Theoretical activities
(Theo-FluEQs) were calculated using the concentration of OCPs and
PCBs and their IC<sub>25</sub>-based relative potency (REP) values.
These total contribution to CALUX-FluEQ was 126%, 84%, 53%, 55%, and
44% for striped dolphin, Steller’s sea eagle, Stejneger’s
beaked whale, finless porpoise, and golden eagle, respectively, and
the main contributor was <i>p</i>,<i>p</i>′-DDE.
However, most of the activities for raccoon dog (7.6%) and common
cormorant (17%) could not be explained by OCPs and PCBs. This suggests
other unknown compounds could function as AR antagonists in these
terrestrial species
Similarities in the Endocrine-Disrupting Potencies of Indoor Dust and Flame Retardants by Using Human Osteosarcoma (U2OS) Cell-Based Reporter Gene Assays
Indoor
dust is a sink for many kinds of pollutants, including flame retardants
(FRs), plasticizers, and their contaminants and degradation products.
These pollutants can be migrated to indoor dust from household items
such as televisions and computers. To reveal high-priority end points
of and contaminant candidates in indoor dust, using CALUX reporter
gene assays based on human osteosarcoma (U2OS) cell lines, we evaluated
and characterized the endocrine-disrupting potencies of crude extracts
of indoor dust collected from Japan (<i>n</i> = 8), the
United States (<i>n</i> = 21), Vietnam (<i>n</i> = 10), the Philippines (<i>n</i> = 17), and Indonesia
(<i>n</i> = 10) and for 23 selected FRs. The CALUX reporter
gene assays used were specific for compounds interacting with the
human androgen receptor (AR), estrogen receptor α (ERα),
progesterone receptor (PR), glucocorticoid receptor (GR), and peroxisome
proliferator-activated receptor γ2 (PPARγ2). Indoor dust
extracts were agonistic to ERα, GR, and PPARγ2 and antagonistic
against AR, PR, GR, and PPARγ2. In comparison, a majority of
FRs was agonistic to ERα and PPARγ2 only, and some FRs
demonstrated receptor-specific antagonism against all tested nuclear
receptors. Hierarchical clustering clearly indicated that agonism
of ERα and antagonism of AR and PR were common, frequently detected
end points for indoor dust and tested FRs. Given our previous results
regarding the concentrations of FRs in indoor dust and in light of
our current results, candidate contributors to these effects include
not only internationally controlled brominated FRs but also alternatives
such as some phosphorus-containing FRs. In the context of indoor pollution,
high-frequency effects of FRs such as agonism of ERα and antagonism
of AR and PR are candidate high-priority end points for further investigation
Organohalogen Compounds in Pet Dog and Cat: Do Pets Biotransform Natural Brominated Products in Food to Harmful Hydroxlated Substances?
There
are growing concerns about the increase in hyperthyroidism
in pet cats due to exposure to organohalogen contaminants and their
hydroxylated metabolites. This study investigated the blood contaminants
polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers
(PBDEs) and their hydroxylated and methoxylated derivatives (OH-PCBs,
OH-PBDEs, and MeO-PBDEs), in pet dogs and cats. We also measured the
residue levels of these compounds in commercially available pet foods.
Chemical analyses of PCBs and OH-PCBs showed that the OH-PCB levels
were 1 to 2 orders of magnitude lower in cat and dog food products
than in their blood, suggesting that the origin of OH-PCBs in pet
dogs and cats is PCBs ingested with their food. The major congeners
of OH-/MeO-PBDEs identified in both pet food products and blood were
natural products (6OH-/MeO-BDE47 and 2′OH-/MeO-BDE68) from
marine organisms. In particular, higher concentrations of 6OH-BDE47
than 2′OH-BDE68 and two MeO-PBDE congeners were observed in
the cat blood, although MeO-BDEs were dominant in cat foods, suggesting
the efficient biotransformation of 6OH-BDE47 from 6MeO-BDE47 in cats.
We performed in vitro demethylation experiments to confirm the biotransformation
of MeO-PBDEs to OH-PBDEs using liver microsomes. The results showed
that 6MeO-BDE47 and 2′MeO-BDE68 were demethylated to 6OH-BDE47
and 2′OH-BDE68 in both animals, whereas no hydroxylated metabolite
from BDE47 was detected. The present study suggests that pet cats
are exposed to MeO-PBDEs through cat food products containing fish
flavors and that the OH-PBDEs in cat blood are derived from the CYP-dependent
demethylation of naturally occurring MeO-PBDE congeners, not from
the hydroxylation of PBDEs
Identification of Major Dioxin-Like Compounds and Androgen Receptor Antagonist in Acid-Treated Tissue Extracts of High Trophic-Level Animals
We evaluated the applicability of combining <i>in vitro</i> bioassays with instrument analyses to identify potential endocrine disrupting pollutants in sulfuric acid-treated extracts of liver and/or blubber of high trophic-level animals. Dioxin-like and androgen receptor (AR) antagonistic activities were observed in Baikal seals, common cormorants, raccoon dogs, and finless porpoises by using a panel of rat and human cell-based chemical-activated luciferase gene expression (CALUX) reporter gene bioassays. On the other hand, no activity was detected in estrogen receptor α (ERα)-, glucocorticoid receptor (GR)-, progesterone receptor (PR)-, and peroxisome proliferator-activated receptor γ2 (PPARγ2)-CALUX assays with the sample amount applied. All individual samples (<i>n</i> = 66) showed dioxin-like activity, with values ranging from 21 to 5500 pg CALUX-2,3,7,8-tetrachlorodibenzo-<i>p</i>-dioxin equivalent (TEQ)/g-lipid. Because dioxins are expected to be strong contributors to CALUX-TEQs, the median theoretical contribution of dioxins calculated from the result of chemical analysis to the experimental CALUX-TEQs was estimated to explain up to 130% for all the tested samples (<i>n</i> = 54). Baikal seal extracts (<i>n</i> = 31), but not other extracts, induced AR antagonistic activities that were 8–150 μg CALUX-flutamide equivalent (FluEQ)/g-lipid. <i>p,p′</i>-DDE was identified as an important causative compound for the activity, and its median theoretical contribution to the experimental CALUX-FluEQs was 59% for the tested Baikal seal tissues (<i>n</i> = 25). Our results demonstrate that combining <i>in vitro</i> CALUX assays with instrument analysis is useful for identifying persistent organic pollutant-like compounds in the tissue of wild animals on the basis of <i>in vitro</i> endocrine disruption toxicity