Seal Liver Research Articles

Trace elements in Alaska's ice seals in the 2000s and 2010s.

Ringed (Pusa hispida), bearded (Erignathus barbatus), spotted (Phoca largha), and ribbon (Histriophoca fasciata) seals are ice-associated seals that are important subsistence resources for coastal Alaska Native people. These seals are also mid- to upper trophic level Arctic predators and primary prey of polar bears (Ursus maritimus). We analyzed concentrations of 19 trace elements in seal liver, kidney, muscle, and blubber, including arsenic, cadmium, lead, mercury, and vanadium due to their potential toxicity. We also measured monomethyl mercury, the more biologically available and toxic form of mercury, in a subsample of seals. We tested for differences in elemental concentrations by seal sex, age, and two periods, 2003-2007 and 2011-2016, to detect environmental trends, assess seal health, and explore trace elements in seal tissues as indicators of seal diet. Trace element concentrations were within ranges that were similar or below that previously measured for these species throughout their range in the Arctic and subarctic. We found relationships between concentration and seal sex or age, as well as differences between periods, with a notable decline over time in magnesium for bearded seal liver and kidney, and ringed and spotted seal liver. Relative concentrations of methyl mercury and total mercury among the four seal species matched known patterns of piscivory and pelagic feeding. Cadmium concentrations were highest in bearded and ribbon seals, possibly due to greater benthic feeding and consumption of squid, respectively. Tissue trace element concentrations from sick seals collected during the 2011-2016 Northern Alaska Pinnipeds Unusual Mortality Event did not differ from those of healthy subsistence harvested seals. Our analysis of trace elements in four Alaskan ice seal species can inform toxicological risk assessments regarding non-essential elements of concern and assessments of nutritional benefits regarding essential elements for seals and for the people and polar bears that eat them.

Characterizing Important Dietary Exposure Sources of Perfluoroalkyl Acids in Inuit Youth and Adults in Nunavik Using a Feature Selection Tool.

Previous studies have identified the consumption of country foods (hunted/harvested foods from the land) as the primary exposure source of perfluoroalkyl acids (PFAA) in Arctic communities. However, identifying the specific foods associated with PFAA exposures is complicated due to correlation between country foods that are commonly consumed together. We used venous blood sample data and food frequency questionnaire data from the Qanuilirpitaa? ("How are we now?") 2017 (Q2017) survey of Inuit individuals y of age residing in Nunavik (). Adaptive elastic net, a machine learning technique, identified the most important food items for predicting PFAA biomarker levels while accounting for the correlation among the food items. We used generalized linear regression models to quantify the association between the most predictive food items and six plasma PFAA biomarker levels. The estimates were converted to percent changes in a specific PFAA biomarker level per standard deviation increase in the consumption of a food item. Models were also stratified by food type (market or country foods). Perfluorooctanesulfonic acid (PFOS), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) were associated with frequent consumption of beluga misirak (rendered fat) [14.6%; 95% confidence interval (CI): 10.3%, 18.9%; 14.6% (95% CI: 10.1%, 19.0%)], seal liver [9.3% (95% CI: 5.0%, 13.7%); 8.1% (95% CI: 3.5%, 12.6%)], and suuvalik (fish roe mixed with berries and fat) [6.0% (95% CI: 1.3%, 10.7%); 7.5% (95% CI: 2.7%, 12.3%)]. Beluga misirak was also associated with higher concentrations of perfluorohexanesulphonic acid (PFHxS) and perfluorononanoic acid (PFNA), albeit with lower percentage changes. PFHxS, perfluorooctanoic acid (PFOA), and PFNA followed some similar patterns, with higher levels associated with frequent consumption of ptarmigan [6.1% (95% CI: 3.2%, 9.0%); 5.1% (95% CI: 1.1%, 9.1%); 5.4% (95% CI: 1.8%, 9.0%)]. Among market foods, frequent consumption of processed meat and popcorn was consistently associated with lower PFAA exposure. Our study identifies specific food items contributing to environmental contaminant exposure in Indigenous or small communities relying on local subsistence foods using adaptive elastic net to prioritize responses from a complex food frequency questionnaire. In Nunavik, higher PFAA biomarker levels were primarily related to increased consumption of country foods, particularly beluga misirak, seal liver, suuvalik, and ptarmigan. Our results support policies regulating PFAA production and use to limit the contamination of Arctic species through long-range transport. https://doi.org/10.1289/EHP13556.

Alternative and legacy flame retardants in marine mammals from three northern ocean regions

Flame retardants are globally distributed contaminants that have been linked to negative health effects in humans and wildlife. As top predators, marine mammals bioaccumulate flame retardants and other contaminants in their tissues which is one of many human-imposed factors threatening population health. While some flame retardants, such as the polybrominated diphenyl ethers (PBDE), have been banned because of known toxicity and environmental persistence, limited data exist on the presence and distribution of current-use alternative flame retardants in marine mammals from many industrialized and remote regions of the world. Therefore, this study measured 44 legacy and alternative flame retardants in nine marine mammal species from three ocean regions: the Northwest Atlantic, the Arctic, and the Baltic allowing for regional, species, age, body condition, temporal, and tissue comparisons to help understand global patterns. PBDE concentrations were 100–1000 times higher than the alternative brominated flame retardants (altBFRs) and Dechloranes. 2,2′,4,5,5′-pentabromobiphenyl (BB-101) and hexabromobenzene (HBBZ) were the predominant altBFRs, while Dechlorane-602 was the predominant Dechlorane. This manuscript also reports only the second detection of hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO) in marine mammals. The NW Atlantic had the highest PBDE concentrations followed by the Baltic and Arctic which reflects greater historical use of PBDEs in North America compared to Europe and greater industrialization of North America and Baltic countries compared to the Arctic. Regional patterns for other compounds were more complicated, and there were significant interactions among species, regions, body condition and age class. Lipid-normalized PBDE concentrations in harbor seal liver and blubber were similar, but HBBZ and many Dechloranes had higher concentrations in liver, indicating factors other than lipid dynamics affect the distribution of these compounds. The health implications of contamination by this mixture of compounds are of concern and require further research.

Effect of cooking temperature on metal concentrations and speciation in fish muscle and seal liver

Fish and marine mammals constitute a significant part of the country food diet of many Indigenous communities in Canada. These animals sometimes accumulate essential elements as well as elevated levels of toxic metals. We experimentally assessed how changes in cooking temperature (23–99 °C by boiling) modified elemental concentrations in whitefish muscle and grey seal liver (two organs commonly consumed in some northern communities). Wet and dry elemental concentrations changed linearly as a function of temperature, and two patterns were observed: methylmercury, selenium, and rare earth elements tended to remain associated with the food during cooking, whereas alkali, alkaline-earth metals, and arsenic were significantly transferred to cooking juices. Mass balances indicated that speciation of mercury was stable during cooking. Because elements generally behaved similarly as those of their periodic table group or their ecotoxicological classes (A, B, intermediate), we propose that elemental behavior during cooking is partly a function of chemical affinity, and this relationship can be used to predict the behavior of data-poor elements of emerging concern, such as technology-critical elements. Furthermore, the marked increases and decreases in elemental concentrations during cooking (e.g., −14% As and +39% Se in whitefish; −22% Cd and +55% Hg in seal liver, on a wet weight basis) should be considered when assessing risk because current exposure models usually only consider elemental concentrations in raw food.

Contamination of country foods by perfluoroalkyl acids in the Arctic

BACKGROUND AND AIM: Perfluoroalkyl acids (PFAAs) are synthetic chemicals used in industrial and consumer applications. They are exceptionally stable and highly mobile in the environment, and have been detected in high concentrations in Nunavik Inuit adults. The study’s objectives were to study the associations between dietary profiles in Nunavik and PFAAs concentrations, and the associations between specific foods and PFAAs concentrations. METHODS: The study used data from the Qanuilirpitaa? 2017 Nunavik Inuit Health Survey. Nine PFAAs congeners were measured in plasma samples, including perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUdA). Dietary profiles were identified using latent profile analysis. Multiple linear regression models regressed log-transformed PFAAs concentrations against the dietary profiles, adjusting for sociodemographic variables. Elastic net was used to look at associations between PFAAs and dietary variables. RESULTS: We identified strong associations between the dietary profile defined by frequent country food consumption and all PFAAs congeners (PFOA, PFNA, PFDA, PFUdA, PFHxS, and PFOS) compared to the dietary profile defined by frequent market food consumption. Individuals with low consumption of all foods also had higher concentrations of all PFAAs congeners compared to individuals with frequent market food consumption. The associations were stronger with profiles defined by more frequent country food consumption, and particularly those with increased marine mammal consumption. Elastic net identified marine mammal products (seal liver, beluga misirak), wild birds (ptarmigan, goose eggs), Arctic char and fish roe as main exposure sources. CONCLUSIONS: Increased country food consumption was strongly associated with higher PFAAs concentrations, particularly PFOS and long-chain PFAAs congeners. The results provide further evidence that Arctic communities are disproportionately impacted by PFAAs, and further national and international regulations are required to protect the exceptional quality of country foods. KEYWORDS: PFAS; exposure; food; Indigenous

Age-specific trace element bioaccumulation in grey seals from the Gulf of St. Lawrence

We measured concentrations of 19 trace elements and mercury speciation in grey seals (Halichoerus grypus) from the Gulf of St. Lawrence (GSL), Canada. With interest growing in commercializing grey seal products for human consumption in this region, our goal was to measure essential and non-essential trace elements in grey seals to evaluate health concerns and nutritional benefits. From 2015 to 2019, 120 grey seals were sampled by hunters and researchers at 4 sites in the GSL. Muscle, liver, heart and kidney samples were analyzed for 10 non-essential elements (Sb, As, Be, B, Cd, Pb, Hg, Ni, Tl, Sn) and 9 essential elements (Co, Cr, Cu, Fe, Mg, Mn, Mo, Se, Zn). Both total mercury (THg) and methylmercury (MeHg) were analyzed for a subset of samples. Results showed a two-step bioaccumulation pattern with lower element concentrations in the muscle (Fe, Mg, Se) and livers (Cd, Cr, Hg, Mn, Mo, Se) of young-of-the-year harvested in the winter (<6 wks old) compared to older animals feeding at sea. We did not observe progressive age-dependent bioaccumulation for older seals (∼5 mos–29 yrs). Sex-specific differences were not very pronounced, but a few elements were 30–70% higher in the muscle (THg, MeHg) and liver (Mn, Zn) of male seals. Comparison to Canadian dietary reference intakes shows that a weekly portion of liver from young-of-the-year (<6 wks old) is a good source of essential elements (Cu, Fe) and that muscle and liver from this age category do not exceed reference values for toxic elements (As, Cd, Pb, MeHg). Discussions with regional public health professionals are on-going to develop dietary recommendations for the consumption of older grey seals.

Relationships between gene transcription and contaminant concentrations in Baltic ringed seals: A comparison between tissue matrices.

Ringed seals (Pusa hispida) are slowly recovering in the eastern and northern parts of the Baltic Sea after years of hunting pressure and contaminant exposure. Still, consequences of anthropogenic activities such as contaminant exposure and increasing temperatures are stressors that continue to have deleterious effects on their habitat and health. Transcription profiles of seven health-related genes involved in xenobiotic metabolism, endocrine disruption and stress were evaluated in blood, blubber, and liver of Baltic ringed seals in a multi-tissue approach. Selected persistent organic pollutants and total mercury concentrations were measured in blubber and liver, and muscle and liver of these animals, respectively. Concentrations of contaminants varied across tissues on a lipid weight basis but not with sex. mRNA transcript levels for all seven target genes did not vary between sexes or age classes. Transcript levels of thyroid hormone receptor alpha (TRα), retinoic acid receptor alpha (RARα) and heat shock protein 70 (HSP70) correlated with levels of persistent organic pollutants. TRα transcript levels also correlated positively with mercury concentrations in the liver. Of the three tissues assessed in this multi-tissue approach, blubber showed highest transcription levels of aryl hydrocarbon receptor nuclear translocator (ARNT), thyroid stimulating hormone receptor beta (TSHβ), oestrogen receptor alpha (ESR1) and peroxisome proliferator activated receptor alpha (PPARα). The wide range of genes expressed highlights the value of minimally invasive sampling (e.g. biopsies) for assessing health endpoints in free-ranging marine wildlife and the importance of identifying optimal matrices for targeted gene expression studies. This gene transcript profile study has provided baseline information on transcript levels of biomarkers for early on-set health effects in ringed seals and will be a useful guide to assess the impacts of environmental change in Baltic pinnipeds for conservation and management.

Epidemiology associated with the exposure to Toxoplasma gondii in Nunavik’s Inuit population using the 2017 Qanuilirpitaa cross‐sectional health survey

Foci of high seroprevalence against Toxoplasma gondii are observed in Nunavik, the Inuit land of Northern Quebec (Canada). Considering the rare occurrence of felids in the region, exposure is suspected to be driven by water- and food-borne transmission routes. Hypotheses were that drinking untreated water from natural sources and eating country food mostly raw increased the risk of exposure to the parasite. Data from 1,300 Inuit participants of the 2017 Nunavik Health Survey were included in three weighted robust Poisson regression models. The effect of three types of exposure variables: (1) water treatment (yes/no) and if country food was mostly eaten raw (yes/no); (2) main source of drinking water (bottled/municipal/natural) and frequency of country food consumption (continuous) and (3) drinking water risk (low/intermediate/high) and frequency of a raw country food consumption (continuous), on the presence of Toxoplasma antibodies were estimated. Models were adjusted for age, sex and ecological region, with multiple sensitivity analyses being performed. Toxoplasma gondii seroprevalences were consistently correlated with age quadratically, sex (prevalence ratio=PRwoman/man ranged from 1.18 to 1.22), ecological region (PRHudsonBay/HudsonStrait ranged from 2.18 to 2.41; PRHudsonBay/UngavaBay ranged from 1.52 to 1.59) and consuming bivalve mollusc/urchin (PR varied from 1.02 to 1.21) across all three models. Each increase of two consumptions per month of beluga (PR ranged from 1.01 to 1.03), seal liver (PR ranged from 1.01 to 1.02) and goose (PR ranged from 1.01 to 1.02) were also associated with seropositivity, albeit more clearly in models 2 and 3, while drinking water mainly from natural (PR of 1.47) or municipal (PR=1.42) sources compared to bottled water, was correlated with seroprevalence, although results were compatible with the null. Our results suggest that both the oocyst- (mollusc/urchin, drinking water) and cyst-borne (walrus, seal liver and goose) transmission pathways could be present in Nunavik.

Mercury in Ringed Seals (Pusa hispida) from the Canadian Arctic in Relation to Time and Climate Parameters.

Mercury is found in Arctic marine mammals that are important in the diet of northern Indigenous peoples. The objectives of the present long‐term study, spanning a 45‐yr period, were to 1) investigate the temporal trends of total mercury (THg; muscle and liver) and selenium (Se; liver) in ringed seals (Pusa hispida) from different regions of the Canadian Arctic; and 2) examine possible relationships with age, diet, and climate parameters such as air temperature, precipitation, climatic indices, and ice‐coverage. Ringed seals were collected by hunters in northern communities in the Beaufort Sea, Central Arctic, Eastern Baffin Island, Hudson Bay, and Ungava/Nunatsiavut regions (Canada) between 1972 and 2017. Mercury levels did not change through time in seal liver, but THg levels in muscle decreased in seals from Hudson Bay (−0.91%/yr) and Ungava/Nunatsiavut (−1.30%/yr). Carbon stable isotope values in seal muscle decreased significantly through time in 4 regions. Selenium‐to‐THg ratios were found to be >1 for all years and regions. Variation partitioning analyses across regions indicated that THg trends in seals were mostly explained by age (7.3–21.7%), climate parameters (3.5–12.5%), and diet (up to 9%); climate indices (i.e., Arctic and North Atlantic Oscillations, Pacific/North American pattern) explained the majority of the climate portion. The THg levels had a positive relationship with Arctic Oscillation for multiple regions. Associations of THg with air temperature, total precipitation, and sea‐ice coverage, as well as with North Atlantic Oscillation and Pacific/North American pattern were found to vary with tissue type and geographical area. Environ Toxicol Chem 2020;39:2462–2474. © 2020 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Fisheries and Oceans Canada.

Bioaccumulation and biomagnification of perfluoroalkyl acids and precursors in East Greenland polar bears and their ringed seal prey

The bioaccumulation and biomagnification of 22 major perfluoroalkyl substances (PFAS) were investigated in tissues of polar bears (Ursus maritimus) and their major prey species, the ringed seal (Pusa hispida), from the Scoresby Sound region of East Greenland. In polar bear liver the mean Σ4PFSA (perfluoroalkyl sulfonic acid) concentration (C4, C6, C8 and C10) was 2611 ± 202 ng/g wet weight (ww; 99% perfluorooctane sulfonate (PFOS)) and two orders of magnitude higher than the 20 ± 3 ng/g ww (89% PFOS) concentration in fat. The mean Σ4PFSAs in seal liver was 111 ± 5 ng/g ww (98% PFOS) and three orders of magnitude higher relative to the 0.05 ± 0.01 ng/g ww concentration in blubber (100% perfluorohexane sulfonate). Perfluoro-1-octane sulfonamide (FOSA) was quantifiable in bear (mean 10 ± 1.4 ng/g ww) and seal (mean 0.6 ± 0.1 ng/g ww) liver but not in fat or blubber. The mean Σ13PFCAs (C4–C18; perfluoroalkyl carboxylic acids) in bear liver (924 ± 71 ng/g ww) was much greater than in seal liver (74 ± 6 ng/g ww). In bear fat and seal blubber, the mean Σ13PFCAs were 15 ± 1.9 and 0.9 ± 0.1 ng/g ww, respectively. Longer chain C11 to C14 PFCAs dominated in bear fat and seal blubber (60–80% of Σ13PFCA), whereas shorter-chain C9 to C11 PFCAs dominated in the liver (85–90% of Σ13PFCA). Biomagnification factors (BMFs) were orders of magnitude greater for PFHxS and C9 to C13 PFCAs when based on bear liver to seal blubber rather than bear liver to seal liver, and PFCA (C9 to C13) BMFs decreased with increasing chain length. Seal blubber to bear liver BMFs better reflects the dietary exposure relationship of PFAS between bears and seals.

137Cs and 40K in gray seals Halichoerus grypus in the southern Baltic Sea

This study presents levels of 137Cs and 40K concentrations in the placentas of seals gathered in the period 2007–2015. The mean activity of 137Cs and 40K was 5.49 Bq kg−1w.w. and 136.6 Bq kg−1 ww respectively. Statistically significant correlation was observed between the 137Cs activities in placenta and in herring—the staple food for seals. The concentrations of 137Cs and 40K were also determined in other tissues (muscle, liver, lung, and brain) of wild seals. The concentrations of 137Cs were from 2.59 Bq−1 ww (lungs) to 24.3 Bq kg−1 ww (muscles). The transfer factor values for 137Cs (seal tissue/fish) ranged from 0.89 to 2.42 in the case of the placentas and from 1.35 to 8.17 in the case of the muscle. For adults seal, the effective dose from 137Cs was 2.98 nGy h−1. The mean external radiation dose to pup was 0.77 nGy h−1 from 137Cs and 6.69 nGy h−1 from 40K.

Occurrence of substituted diphenylamine antioxidants and benzotriazole UV stabilizers in Arctic seabirds and seals

Substituted diphenylamine antioxidants (SDPAs) and benzotriazole UV stabilizers (BZT-UVs) are contaminants of emerging environmental concern. However, little is known about the occurrence of these contaminants in the Arctic. In this study, we investigated the levels of 11 SDPAs and 6 BZT-UVs in livers and eggs of two seabird species, the black-legged kittiwake (Rissa tridactyla) and northern fulmar (Fulmarus glacialis), as well as the liver of ringed seals (Pusa hispida) from Canadian high- and sub-Arctic sites. The concentrations of ΣSDPAs in seabird livers (median 336 pg g−1, wet weight (ww)) were significantly higher than the eggs (median 24 pg g−1, ww) and the seal livers (median 38 pg g−1, ww), suggesting liver was a primary tissue of SDPA accumulation in seabirds and that seabirds were at greater risk of exposure to SDPAs than marine mammals in the Arctic. The predominant SDPA was monostyryl octyl-diphenylamine and this compound was detected in every seabird and seal sample, indicating the widespread distribution of this contaminant in Arctic food webs. Unlike SDPAs, the detection rate and concentrations of BZT-UVs in seals were higher than in seabirds. The compound 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol (UV329) or its isomer 2-(2H-benzotriazol-2-yl)-4-(tert-butyl)-6-(sec-butyl) phenol (UV350) was the predominant BZT-UVs in seals, with the concentrations of ΣBZT-UVs between <method quantification limits and 1.66 × 104 pg g−1 (ww) (median: 2.36 × 103 pg g−1, ww). This is the first report of the different distribution patterns of SDPAs and BZT-UVs in wildlife from Canadian Arctic sites.

Organ-specific differences in mercury speciation and accumulation across ringed seal (Phoca hispida) life stages

Methylmercury (MeHg) is a central nervous system toxicant and exposures can adversely affect the health of marine mammals. Mercuric selenide (HgSe) in marine mammal tissues is hypothesized to result from a protective detoxification mechanism, but toxicokinetic processes contributing to its formation are poorly understood. Here, new data is reported on speciated Hg concentrations in multiple organs of n = 56 ringed seals (Phoca hispida) from Labrador, Canada, and compare concentrations to previously published data from Greenland seals. A higher proportion of Hg is found to accumulate in the kidney of young-of-the-year (YOY) ringed seals compared to adults. A toxicokinetic model for Hg species is developed and evaluated to better understand factors affecting variability in Hg concentrations among organs and across life stages. Prior work postulated that HgSe formation only occurs in the liver of mature seals, but model results suggest HgSe formation occurs across all life stages. Higher proportions of HgSe in mature seal livers compared to YOY seals likely results from the slow accumulation and elimination of HgSe (total body half-life = 500 days) compared to other Hg species. HgSe formation in the liver reduces modeled blood concentrations of MeHg by only 6%. Thus, HgSe formation may not substantially reduce MeHg transport across the blood-brain barrier of ringed seals, leaving them susceptible to the neurotoxic effects of MeHg exposure.

Hg-Stable Isotope Variations in Marine Top Predators of the Western Arctic Ocean

Recent studies on mercury (Hg)-stable isotopes in Alaskan seabird eggs and ringed seal livers illustrated the control of sea ice cover on marine methyl-Hg photochemistry. Here, complementary marine mammal tissues have been analyzed to document variations in Hg-, carbon (C)-, and nitrogen (N)-stable isotope compositions of Arctic marine food webs. Hg-stable isotope ratios were measured in liver samples of 55 beluga whales (Delphinapterus leucas) and 15 polar bears (Ursus maritimus) collected since 1990. Large variations in δ202Hg (≈2.1‰) and Δ199Hg (≈1.7‰) are observed between species and within species stocks covering the Gulf of Alaska–Bering Sea–Arctic Ocean regions. Polar bears, mainly feeding on ringed seal (δ15N shift of 4.2‰), show identical liver Δ199Hg of 0.5‰, confirming the absence of metabolic mass-independent fractionation, and 0.33 ± 0.11‰ enrichment in heavy Hg isotopes. Beluga whale liver total Hg concentrations increase with age, reflecting lifetime bioaccumulation, while Hg speciation shi...

Morphometric, molecular and histopathologic description of hepatic infection by Orthosplanchnus arcticus (Trematoda: Digenea: Brachycladiidae) in ringed seals (Pusa hispida) from Northwest Greenland

For the first time in > 30 years of routine sampling under the Arctic Monitoring and Assessment Program, a parasite was found in the liver of ringed seals (Phoca hispida) collected near Qaanaaq (Thule), Northwest Greenland, in 2008 and 2014. Concerns regarding changes to parasite occurrence, possibly related to climate change and bioaccumulation of immunomodulating anthropogenic pollutants, spurred further investigations into parasite characterization, and implications for wildlife health and seal hunters. Microscopic, molecular, and morphometric analyses are presented herein. Of 40 seals, 6 (15%) were infected, and 5 of 6 of these seals had severe infections. The parasite was identified morphologically as Orthosplanchnus arcticus Odhner, 1905 (Trematoda; Digenea: Brachycladiidae). Macro- and microscopic pathologic study indicated mild-to-severe biliary hyperplasia associated, stasis associated, and fibrosis associated with trematode infections. Molecular analysis of the trematode confirmed its classification within the Brachycladiidae using sequencing and comparing Internal Transcribed Spacer-1, mitochondrial-NADH Dehydrogenase 3, 18S ribosomal DNA, and Cyclooxygenase-1 regions. This is the first ever report of O. arcticus in ringed seals from Qaanaaq and is one of the most northern records of this parasite. We found significant liver pathology in severely infected seals, but its effects on health of seals in this population are unknown. Host-specificity and the lifecycle of O. arcticus are unknown, but transmission may involve subsistence and commercially harvested Arctic fish species. Further work is needed to answer these questions. Surveying parasites in Arctic wildlife is important in order to assess potential effects on wildlife and human health (i.e., zoonoses).

Isolation of Brucella pinnipedialis from Grey Seals (Halichoerus grypus) in the Baltic Sea.

Brucella infection in seals was reported for the first time in 1994 around the coast of Scotland. Since then, marine mammal Brucella infections were found to be widely distributed in the northern hemisphere. Two Brucella species affect marine mammals: Brucella pinnipedialis in pinnipeds and Brucella ceti in cetaceans. We examined the livers of Baltic grey seals (Halichoerus grypus) from the Finnish coast (n=122) hunted, found dead, or killed as by-catch in fishing gear in 2013-15 as part of population health monitoring. We detected B. pinnipedialis in the livers of three grey seals. The bacterium was isolated from livers displaying parasitic cholangitis. We also detected Brucella DNA in liver flukes (Pseudamphistomum truncatum) obtained from a Brucella-infected grey seal, suggesting that flukes might be possible vectors of this pathogen in the marine environment.

Activity concentration measurements of selected radionuclides in seals from Canadian Arctic

The activity concentrations of naturally occurring radionuclides (such as 226Ra, 210Pb and 210Po) and long lived 137Cs were measured in a total of 119 tissue samples (43 blubber, 43 liver, and 33 muscle samples) from 40 ringed seals and 4 bearded seals collected in the Arviat area of Canada during the fall of 2014. Activity concentration of 210Po was measured in all seal liver and muscle samples individually. The average 210Po activity concentrations were 25 ± 7.6 Bq/kg fresh weight (fw) in muscle and 211 ± 58 Bq/kg fw in liver for ringed seals, and 20 ± 6.1 Bq/kg fw in muscle and 231 ± 150 Bq/kg fw in liver for bearded seals. Due to insufficient sample material for most samples collected, gamma counting for radioactive caesium and radiochemical analysis for 226Ra and 210Pb were performed for pooled samples. Activity concentrations of 210Pb and 226Ra were generally below detection limits. While 134Cs activity concentration was not detectable, 137Cs activity concentration was detected in muscle and liver samples. On average, the 137Cs activity concentrations were 0.25 ± 0.05 and 0.12 ± 0.04 Bq/kg fw in muscle and liver samples of ringed seals, and 0.11 ± 0.02 and 0.10 ± 0.03 Bq/kg fw in muscle and liver samples of bearded seals, respectively. Neither 210Po nor 137Cs were detected in the blubber samples. This study confirmed that 210Po is the dominant contributor to radiation doses resulting from seal consumption. Man-made contaminant 137Cs only contributes less than 0.01% of the total ingestion dose obtained from Arviat seals.

Mercury in the ecosystem of Admiralty Bay, King George Island, Antarctica: Occurrence and trophic distribution

Mercury (Hg) can reach the environment through natural and human-related sources, threatening ecosystems all over the planet due to its well known deleterious effects. Therefore, Antarctic trophic webs, despite being relatively isolated, are not exempt of its influence. To evaluate Hg concentrations in an Antarctic ecosystem, different tissues from 2 species of invertebrates, 2 of fish, 8 of birds, 4 of pinnipeds and at least 5 of vegetation were investigated (n=176). For animals, values ranged from 0.018 to 48.7μgg−1 dw (whole Antarctic krill and Antarctic Fur Seal liver). They were generally correlated to trophic position (assessed by δ15N and δ13C) but also to cephalopods and myctophids consumption. For vegetation, values ranged from 0.014 to 0.227μgg−1 dw (Colobanthus quitensis and an unidentified lichen), with lichens presenting significantly higher values than mosses, likely due to year-round exposure and absorption of animal derived organic matter, as hypothesized by literature.

Studying Closed Hydrodynamic Models of "In Vivo" DNA Perfusion in Pig Liver for Gene Therapy Translation to Humans.

IntroductionExpressing exogenous genes after naked DNA delivery into hepatocytes might achieve sustained and high expression of human proteins. Tail vein DNA injection is an efficient procedure for gene transfer in murine liver. Hydrodynamic procedures in large animals require organ targeting, and improve with liver vascular exclusion. In the present study, two closed liver hydrofection models employing the human alpha-1-antitrypsin (hAAT) gene are compared to reference standards in order to evaluate their potential clinical interest.Material and MethodsA solution of naked DNA bearing the hAAT gene was retrogradely injected in 7 pig livers using two different closed perfusion procedures: an endovascular catheterization-mediated procedure (n = 3) with infrahepatic inferior vena cava and portal vein blockage; and a surgery-mediated procedure (n = 4) with completely sealed liver. Gene transfer was performed through the suprahepatic inferior cava vein in the endovascular procedure and through the infrahepatic inferior vena cava in the surgical procedure. The efficiency of the procedures was evaluated 14 days after hydrofection by quantifying the hAAT protein copies per cell in tissue and in plasma. For comparison, samples from mice (n = 7) successfully hydrofected with hAAT and healthy human liver segments (n = 4) were evaluated.ResultsGene decoding occurs efficiently using both procedures, with liver vascular arrest improving its efficiency. The surgically closed procedure (sealed organ) reached higher tissue protein levels (4x10^5- copies/cell) than the endovascular procedure, though the levels were lower than in human liver (5x10^6- copies/cell) and hydrofected mouse liver (10^6- copies/cell). However, protein levels in plasma were lower (p<0.001) than the reference standards in all cases.ConclusionHydrofection of hAAT DNA to “in vivo” isolated pig liver mediates highly efficient gene delivery and protein expression in tissue. Both endovascular and surgically closed models mediate high tissue protein expression. Impairment of protein secretion to plasma is observed and might be species-related. This study reinforces the potential application of closed liver hydrofection for therapeutic purposes, provided protein secretion improves.

Mercury diminishes the cardiovascular protective effect of omega-3 polyunsaturated fatty acids in the modern diet of Inuit in Canada

BackgroundInuit in Canada have low reported incidence of myocardial infarction (MI) because of their traditional rich n-3 fatty acids marine diet. They are experiencing rapid nutrition transition and ischemic heart disease is now becoming a health concern. ObjectivesOur goal was to describe the modern Inuit diet, the eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and methyl mercury (MeHg) intake and estimate their contributions to the risk of MI. We also estimated the effect of promoting the consumption of more traditional food on Inuit's MI risk. MethodsWe estimated the effect of Inuit diet on MI risk with modelling. Model formulas and assumptions were extracted from various epidemiology studies and literatures. International Polar Year Inuit Health Survey (IHS) was a comprehensive health and nutrition survey conducted in 2007–8 with 2072 participants (aged 18–79) in Canada. Traditional food intake, blood biomarkers values from the IHS served as the baseline parameters of model input. ResultsInuit traditional diet contained both high level of EPA, DHA and MeHg and their combined net effect was estimated to reduce the relative risk of MI by 1% for men and 2% for women. Arctic char meat provided the largest amount of EPA and DHA. Ringed seal liver was the main source for MeHg. Increase intake of selected fish, like salmon, herring and Arctic char by 75g per day can reduce the relative risk of MI (RR 0.70, 0.78 and 0.90 respectively). ConclusionsIn the Inuit diet, the beneficial effect on MI of EPA and DHA is diminished by the adverse effect of MeHg. Promoting the increase consumption of fish species with high EPA+DHA and low MeHg may help to prevent MI among Inuit.