| 1. |
- Pedrelli, M., et al.
(författare)
-
Athero-protective properties of plasma lipoproteins from brown bears (URSUS ARCTOS) during hibernation and active state
- 2020
-
Ingår i: Atherosclerosis. - : Elsevier. - 0021-9150 .- 1879-1484. ; 315, s. E69-E70
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background and Aims: Plasma cholesterol (TC) and triglyceride (TG) levels are twice as high in hibernating brown bears (Ursus arctos) than in healthy humans. Yet, bears display no signs of atherosclerosis. To explore this apparent paradox, lipoprotein structure and function of brown bears were analyzed and compared with those of healthy humans.Methods: Blood from the same wild free-ranging Swedish brown bears (n=10) was drawn during hibernation (winter) and active state (summer). Plasma lipoproteins were separated by size exclusion chromatography, ultracentrifugation and gel-electrophoresis. LDL binding to arterial proteoglycans (PGs) was measured. Data are presented as median (10th - 90th percentile).Results: During hibernation bear LDL carried 4.6 (2.3-5.9) mmol/L cholesterol esters (CE), 1.5 (1.1-2.4) mmol/L unesterified (UC), 3.7 (2.1-4.9) mmol/L TG and 2.5 (1.8-3.4) mmol/L phospholipid (PL). Human LDL were smaller than bear LDL, which were proportionally richer in TG (winter 31 (26-33)%, summer 30 (22-40)%vs human 9% (7-15); p<0.001) and had less CE (winter 36 (26-45)%, summer 25 (21-37)%vs human 48 (46-55)%; p<0.01)). Bear LDL were less positively charged and showed a pre-ß motility on agarose gel. Thus, bear LDL had about 10 times lower binding to PGs than human LDL.Conclusions: Despite high TC and TG levels, bear lipoproteins were less atherogenic than the human analogues. This was due to low LDL affinity for PGs, secondary to increased TG and PL, and to low positive charge. Our study provides further mechanistic insights for the atherosclerosis development, which is driven by the circulating lipoprotein composition and functions rather than plasma absolute lipid levels.
|
|
| 2. |
- Ecke, Frauke, et al.
(författare)
-
Sublethal Lead Exposure Alters Movement Behavior in Free-Ranging Golden Eagles
- 2017
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 51:10, s. 5729-5736
-
Tidskriftsartikel (refereegranskat)abstract
- Lead poisoning of animals due to ingestion of fragments from lead-based ammunition in carcasses and offal of shot wildlife is acknowledged globally and raises great concerns about potential behavioral effects leading to increased mortality risks. Lead levels in blood were correlated with progress of the moose hunting season. Based on analyses of tracking data, we found that even sublethal lead concentrations in blood (25 ppb, wet weight), can likely negatively affect movement behavior (flight height and movement rate) of free ranging scavenging Golden Eagles (Aquila chrysaetos). Lead levels in liver of recovered post-mortem analyzed eagles suggested that sublethal exposure increases the risk of mortality in eagles. Such adverse effects on animals are probably common worldwide and across species, where game hunting with lead-based ammunition is widespread. Our study highlights lead exposure as a considerably more serious threat to wildlife conservation than previously realized and suggests implementation of bans of lead ammunition for hunting.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Fröbert, Ole, 1964-, et al.
(författare)
-
Platelet function in brown bear (Ursus arctos) compared to man
- 2010
-
Ingår i: Thrombosis Journal. - London, UK : BioMed Central (BMC). - 1477-9560. ; 8, s. 11-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Information on hemostasis and platelet function in brown bear (Ursus arctos) is of importance for understanding the physiological, protective changes during hibernation.Objective: The study objective was to document platelet activity values in brown bears shortly after leaving the den and compare them to platelet function in healthy humans.Methods: Blood was drawn from immobilized wild brown bears 7-10 days after leaving the den in mid April. Blood samples from healthy human adults before and after clopidogrel and acetylsalicylic acid administration served as control. We analyzed blood samples by standard blood testing and platelet aggregation was quantified after stimulation with various agonists using multiple electrode aggregometry within 3 hours of sampling.Results: Blood samples were collected from 6 bears (3 females) between 1 and 16 years old and from 10 healthy humans. Results of adenosine diphosphate, aspirin, and thrombin receptor activating peptide tests in bears were all half or less of those in humans. Platelet and white blood cell counts did not differ between species but brown bears had more and smaller red blood cells compared with humans.Conclusion: Using three different tests, we conclude that platelet function is lower in brown bears compared to humans. Our findings represent the first descriptive study on platelet function in brown bears and may contribute to explain how bears can endure denning without obvious thrombus building. However, the possibility that our findings reflect test-dependent and not true biological variations in platelet reactivity needs further studies.
|
|
| 7. |
- Fröbert, Ole, 1964-, et al.
(författare)
-
The brown bear as a translational model for sedentary lifestyle related diseases
- 2020
-
Ingår i: Journal of Internal Medicine. - : Wiley-Blackwell Publishing Inc.. - 0954-6820 .- 1365-2796. ; 287:3, s. 263-270
-
Forskningsöversikt (refereegranskat)abstract
- Sedentary lifestyle accelerates biological aging, is a major risk factor for developing metabolic syndrome and is associated with cardiovascular disease, diabetes mellitus, kidney failure, sarcopenia and osteoporosis. In contrast to the linear path to worsening health in humans with metabolic syndrome, brown bears have developed a circular metabolic plasticity enabling these animals to tolerate obesity and a "sedentary lifestyle" during hibernation and exit the den metabolically healthy in spring. Bears are close to humans physiology-wise, much closer than rodents, the preferred experimental animals in medical research, and may better serve as translational model to develop treatments for lifestyle-related diseases. In this review aspects of brown bear hibernation survival strategies are outlined and conceivable experimental strategies to learn from bears are described.
|
|
| 8. |
- Fuchs, Boris, et al.
(författare)
-
High concentrations of lead (Pb) in blood and milk of free-ranging brown bears (Ursus arctos) in Scandinavia
- 2021
-
Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 287
-
Tidskriftsartikel (refereegranskat)abstract
- Exposure to lead (Pb) is a global health problem for both humans and wildlife. Despite a dramatic decline in human Pb exposure following restrictions of leaded gasoline and industry and thereby an overall reduction of Pb entering the environment, Pb exposure continues to be a problem for wildlife species. Literature on scavenging terrestrial mammals, including interactions between Pb exposure and life history, is however limited.We quantified Pb concentration in 153 blood samples from 110 free-ranging Scandinavian brown bears (Ursus arctos), 1–25 years old, using inductively coupled plasma sector field mass spectrometry. We used generalized linear models to test effects of age, body mass, reproduction status and spatial distribution on the blood Pb concentrations of 56 female bears. We sampled 28 females together with 56 dependent cubs and paired their blood Pb concentrations. From 20 lactating females, we measured the Pb concentration in milk.The mean blood Pb concentration was 96.6 μg/L (range: 38.7.0–220.5 μg/L). Both the mean and range are well above established threshold concentrations for developmental neurotoxicity (12 μg/L), increased systolic blood pressure (36 μg/L) and prevalence of kidney disease in humans (15 μg/L). Lactating females had higher Pb blood concentrations compared to younger, non-lactating females. Blood Pb concentrations of dependent cubs were correlated with their mother's blood Pb concentration, which in turn was correlated with the Pb concentration in the milk.Life-long Pb exposure in Scandinavian brown bears may have adverse effects both on individual and population levels. The high blood Pb concentrations found in brown bears contrast the general reduction in environmental Pb contamination over the past decades in Scandinavia and more research is needed to identify the sources and pathways of Pb exposure in the brown bears.
|
|
| 9. |
- Fuchs, Boris, et al.
(författare)
-
Toxic elements in arctic and sub-arctic brown bears: Blood concentrations of As, Cd, Hg and Pb in relation to diet, age, and human footprint
- 2023
-
Ingår i: Environmental Research. - : Academic Press Inc.. - 0013-9351 .- 1096-0953. ; 229
-
Tidskriftsartikel (refereegranskat)abstract
- Contamination with arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb) is a global concern impairing resilience of organisms and ecosystems. Proximity to emission sources increases exposure risk but remoteness does not alleviate it. These toxic elements are transported in atmospheric and oceanic pathways and accumulate in organisms. Mercury accumulates in higher trophic levels. Brown bears (Ursus arctos), which often live in remote areas, are long-lived omnivores, feeding on salmon (Oncorhynchus spp.) and berries (Vaccinium spp.), resources also consumed by humans.We measured blood concentrations of As, Cd, Hg and Pb in bears (n = 72) four years and older in Scandinavia and three national parks in Alaska, USA (Lake Clark, Katmai and Gates of the Arctic) using high-resolution, inductively-coupled plasma sector field mass spectrometry. Age and sex of the bears, as well as the typical population level diet was associated with blood element concentrations using generalized linear regression models.Alaskan bears consuming salmon had higher Hg blood concentrations compared to Scandinavian bears feeding on berries, ants (Formica spp.) and moose (Alces). Cadmium and Pb blood concentrations were higher in Scandinavian bears than in Alaskan bears. Bears using marine food sources, in addition to salmon in Katmai, had higher As blood concentrations than bears in Scandinavia. Blood concentrations of Cd and Pb, as well as for As in female bears increased with age. Arsenic in males and Hg concentrations decreased with age.We detected elevated levels of toxic elements in bears from landscapes that are among the most pristine on the planet. Sources are unknown but anthropogenic emissions are most likely involved. All study areas face upcoming change: Increasing tourism and mining in Alaska and more intensive forestry in Scandinavia, combined with global climate change in both regions. Baseline contaminant concentrations as presented here are important knowledge in our changing world.
|
|
| 10. |
- Ledin, Anna, et al.
(författare)
-
High plasma IgE levels within the Scandinavian wolf population, and its implications for mammalian IgE homeostasis
- 2008
-
Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 45:7, s. 1976-1980
-
Tidskriftsartikel (refereegranskat)abstract
- Immunoglobulin E (IgE) serves as an important link between innate and adaptive immunity through its ability to bind high affinity receptors on mast cells and basophils. Large differences in IgE levels may here affect this important link, and IgE levels in natural non-domestic animal populations may therefore be very informative concerning the levels of IgE that this system have been balanced against during recent mammalian evolution. However, very few such studies have been performed. Here, we present an analysis of total IgE levels in 65 Scandinavian wolves: 57 free living (wild), and 8 wolves in captivity (Zoo). The 57 wild wolves correspond to approximately 30% of the entire wolf population in Sweden and Norway and thus represent a large fraction of the entire population, making this a unique sample from a wild canine population. The median IgE level in these wolves was 67 μg/ml, which is approximately twice the level seen in domestic dogs and more than 100 times the levels in non-atopic humans. The collected information from domestic and wild populations now indicate that the very low IgE levels observed in man and laboratory rodents are most likely an effect of a life in a relatively parasite free environment, and that total IgE levels under maximally stimulatory (normal) conditions may reach 100-200 μg/ml.
|
|
| 11. |
- Moraeus, L., et al.
(författare)
-
Riksmaten Adolescents 2016-17: A national dietary survey in Sweden - design, methods, and participation
- 2018
-
Ingår i: Food & Nutrition Research. - : SNF Swedish Nutrition Foundation. - 1654-6628 .- 1654-661X. ; 62
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Nationally representative information on food consumption data is essential to evaluate dietary habits, inform policy-making and nutritional guidelines, as well as forming a basis for risk assessment and identification of risk groups. Objective: To describe the methods used in the Swedish national dietary survey of adolescents, Riksmaten Adolescents 2016-2017. Design: Students in grades 5, 8, and 11 (mean ages 12, 15, and 18 years) were recruited in this school-based cross-sectional survey. A new, validated, web-based method was used to assess dietary intake. Information on physical activity, health, and socioeconomic background was collected through web questionnaires. Physical activity was also evaluated by accelerometers. Weight and height were measured in all participants, while blood and urine samples were collected in a subsample of 40% of the participants. Results: A total of 3,477 (68%) respondents participated and 3,099 (60%) had complete dietary information. In the subsample, 1,305 (55%) respondents participated and 1,105 (46%) had complete dietary information. The participants were overall representative for the population with regard to socioeconomic background and school organization (public or independent). All types of municipalities were represented in the survey and overall, the geographic distribution corresponded to the underlying population. Some differences by school grade were observed. Sample weights were calculated for the total sample and the subsample. Conclusion: The Riksmaten Adolescents 2016-2017 provides valuable national data on diet, physical activity, and markers of exposure in age groups where data have been lacking. The data will provide a valuable basis for risk assessment, public health policy, and in-depth analyses.
|
|
| 12. |
- Pedrelli, Matteo, et al.
(författare)
-
Vasculoprotective properties of plasma lipoproteins from brown bears (Ursus arctos)
- 2021
-
Ingår i: Journal of Lipid Research. - : Elsevier. - 0022-2275 .- 1539-7262. ; 62
-
Tidskriftsartikel (refereegranskat)abstract
- Plasma cholesterol and triglyceride (TG) levels are twice as high in hibernating brown bears (Ursus arctos) than healthy humans. Yet, bears display no signs of early stage atherosclerosis development when adult. To explore this apparent paradox, we analyzed plasma lipoproteins from the same 10 bears in winter (hibernation) and summer using size exclusion chromatography, ultracentrifugation, and electrophoresis. LDL binding to arterial proteoglycans (PGs) and plasma cholesterol efflux capacity (CEC) were also evaluated. The data collected and analyzed from bears were also compared with those from healthy humans. In bears, the cholesterol ester, unesterified cholesterol, TG, and phospholipid contents of VLDL and LDL were higher in winter than in summer. The percentage lipid composition of LDL differed between bears and humans but did not change seasonally in bears. Bear LDL was larger, richer in TGs, showed prebeta electrophoretic mobility, and had 5-10 times lower binding to arterial PGs than human LDL. Finally, plasma CEC was higher in bears than in humans, especially the HDL fraction when mediated by ABCA1. These results suggest that in brown bears the absence of early atherogenesis is likely associated with a lower affinity of LDL for arterial PGs and an elevated CEC of bear plasma.
|
|
| 13. |
- Sommer, Felix, et al.
(författare)
-
The Gut Microbiota Modulates Energy Metabolism in the Hibernating Brown Bear Ursus arctos
- 2016
-
Ingår i: Cell Reports. - Cambridge, USA : Elsevier BV. - 2211-1247. ; 14:7, s. 1655-1661
-
Tidskriftsartikel (refereegranskat)abstract
- Hibernation is an adaptation that helps many animals to conserve energy during food shortage in winter. Brown bears double their fat depots during summer and use these stored lipids during hibernation. Although bears seasonally become obese, they remain metabolically healthy. We analyzed the microbiota of free-ranging brown bears during their active phase and hibernation. Compared to the active phase, hibernation microbiota had reduced diversity, reduced levels of Firmicutes and Actinobacteria, and increased levels of Bacteroidetes. Several metabolites involved in lipid metabolism, including triglycerides, cholesterol, and bile acids, were also affected by hibernation. Transplantation of the bear microbiota from summer and winter to germ-free mice transferred some of the seasonal metabolic features and demonstrated that the summer microbiota promoted adiposity without impairing glucose tolerance, suggesting that seasonal variation in the microbiota may contribute to host energy metabolism in the hibernating brown bear.
|
|
| 14. |
|
|
| 15. |
|
|
