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Link to original content: https://www.ncbi.nlm.nih.gov/pubmed/22686205
Brown bears (Ursus arctos) seem resistant to atherosclerosis despite highly elevated plasma lipids during hibernation and active state - PubMed Skip to main page content
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. 2012 Jun;5(3):269-72.
doi: 10.1111/j.1752-8062.2011.00370.x. Epub 2012 Jan 10.

Brown bears (Ursus arctos) seem resistant to atherosclerosis despite highly elevated plasma lipids during hibernation and active state

Karin Arinell  1 , Berolla Sahdo, Alina L Evans, Jon M Arnemo, Ulrik Baandrup, Ole Fröbert
Affiliations

Brown bears (Ursus arctos) seem resistant to atherosclerosis despite highly elevated plasma lipids during hibernation and active state

Karin Arinell et al. Clin Transl Sci. 2012 Jun.

Abstract

Hibernation is an extreme physiological challenge for the brown bear (Ursus arctos) in which metabolism is based mainly on lipids. The study objective was to compare plasma lipids in hibernating and active free-ranging brown bears and relate them to arterial histopathology. Blood was drawn from seven immobilized free-ranging brown bears (three females, 2-3 years old) during hibernation in February and from the same bears while active in June and analyzed by enzymatic and automated hematology methods within 48 hours of sampling. Left anterior descending coronary arteries and aortic arches from 12 bears (six females, 1.5-12 years old) killed in hunting were examined by histopathology. Total plasma cholesterol decreased from hibernation to the active period (11.08 ± 1.04 mmol/L vs. 7.89 ± 1.96 mmol/L, P= 0.0028) as did triglyceride (3.16 ± 0.62 mmol/L vs. 1.44 ± 0.27 mmol/L, P= 0.00012) and LDL cholesterol (4.30 ± 0.71 mmol/L vs. 2.02 ± 1.03 mmol/L, P= 0.0075), whereas HDL cholesterol was unchanged. No atherosclerosis, fatty streaks, foam cell infiltration, or inflammation were seen in any arterial samples. Brown bears tolerate elevated cholesterol levels, obesity, physical inactivity, and circulatory slow flow during hibernation without signs of -atherosclerosis. This species might serve as a reverse translational model for atherosclerosis resistance.

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Figures

Figure 1
Figure 1
Individual total plasma cholesterol levels of seven free‐ranging brown bears during hibernation in February and when active in June (A). Analogous graphic presentations of LDL‐cholesterol (B), HDL‐cholesterol (C) and triglycerides (D).
Figure 2
Figure 2
Section of the aortic arch (Mason trichrome stain) from an 8‐year‐old male brown bear weighing 238 kg and shot during hunting. Red color denotes smooth muscle, blue is collagen tissue, and distinct dark fibers signify elastic lamellae. No atherosclerotic changes were found.
Figure 3
Figure 3
Section of the left anterior descending coronary artery (muscular type of artery) from a 4‐year‐old female brown bear weighing 101 kg and shot during hunting (staining as in Figure 1). No atherosclerotic changes were found.
See this image and copyright information in PMC

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