Polar bears (Ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation
Some hibernating animals are known to reduce muscle and bone loss associated with mechanical unloading during prolonged immobilisation, compared to humans. However, here we show that wild pregnant polar bears (Ursus maritimus) are the first known animals to avoid significant bone loss altogether, de...
Published in: | Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology |
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Online Access: | http://hdl.handle.net/2440/53736 https://doi.org/10.1016/j.cbpa.2007.11.012 |
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ftunivadelaidedl:oai:digital.library.adelaide.edu.au:2440/53736 2023-05-15T18:01:47+02:00 Polar bears (Ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation Lennox, Alanda R. Goodship, Allen Edward School of Medical Sciences : Pathology 2008 http://hdl.handle.net/2440/53736 https://doi.org/10.1016/j.cbpa.2007.11.012 en eng Elsevier Science Comparative Biochemistry and Physiology A-Molecular and Integrative Physiology, 2008; 149:203-208 1095-6433 http://hdl.handle.net/2440/53736 doi:10.1016/j.cbpa.2007.11.012 Polar bear Hibernation Disuse osteopenia Mechanical unloading Bone turnover Evolution Osteoporosis Environmental adaptation Journal article 2008 ftunivadelaidedl https://doi.org/10.1016/j.cbpa.2007.11.012 2023-02-05T19:22:14Z Some hibernating animals are known to reduce muscle and bone loss associated with mechanical unloading during prolonged immobilisation, compared to humans. However, here we show that wild pregnant polar bears (Ursus maritimus) are the first known animals to avoid significant bone loss altogether, despite six months of continuous hibernation. Using serum biochemical markers of bone turnover, we showed that concentrations for bone resorption are not significantly increased as a consequence of hibernation in wild polar bears. This is in sharp contrast to previous studies on other hibernating species, where for example, black bears (Ursus americanus), show a 3–4 fold increase in serum bone resorption concentrations post-hibernation, and must compensate for this loss through rapid bone recovery on remobilisation, to avoid the risk of fracture. In further contrast to black bears, serum concentrations of bone formation markers were highly significantly increased in pregnant female polar bears compared to non-pregnant, thus non-hibernating females both prior to and after hibernation. However, bone formation concentrations in new mothers were significantly reduced compared to pre-hibernation concentrations. The de-coupling of bone turnover in favour of bone formation prior to hibernation, suggests that wild polar bears may posses a unique physiological mechanism for building bone in protective preparation against expected osteopenia associated with disuse, starvation, and hormonal drives to mobilise calcium for reproduction, during hibernation. Understanding this physiological mechanism could have profound implications for a natural solution for the prevention of osteoporosis in animals subjected to captivity with inadequate space for exercise, humans subjected to prolonged bed rest while recovering from illness, or astronauts exposed to antigravity during spaceflight. Alanda R. Lennox and Allen E. Goodship Article in Journal/Newspaper polar bear Ursus maritimus The University of Adelaide: Digital Library Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 149 2 203 208 |
institution |
Open Polar |
collection |
The University of Adelaide: Digital Library |
op_collection_id |
ftunivadelaidedl |
language |
English |
topic |
Polar bear Hibernation Disuse osteopenia Mechanical unloading Bone turnover Evolution Osteoporosis Environmental adaptation |
spellingShingle |
Polar bear Hibernation Disuse osteopenia Mechanical unloading Bone turnover Evolution Osteoporosis Environmental adaptation Lennox, Alanda R. Goodship, Allen Edward Polar bears (Ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation |
topic_facet |
Polar bear Hibernation Disuse osteopenia Mechanical unloading Bone turnover Evolution Osteoporosis Environmental adaptation |
description |
Some hibernating animals are known to reduce muscle and bone loss associated with mechanical unloading during prolonged immobilisation, compared to humans. However, here we show that wild pregnant polar bears (Ursus maritimus) are the first known animals to avoid significant bone loss altogether, despite six months of continuous hibernation. Using serum biochemical markers of bone turnover, we showed that concentrations for bone resorption are not significantly increased as a consequence of hibernation in wild polar bears. This is in sharp contrast to previous studies on other hibernating species, where for example, black bears (Ursus americanus), show a 3–4 fold increase in serum bone resorption concentrations post-hibernation, and must compensate for this loss through rapid bone recovery on remobilisation, to avoid the risk of fracture. In further contrast to black bears, serum concentrations of bone formation markers were highly significantly increased in pregnant female polar bears compared to non-pregnant, thus non-hibernating females both prior to and after hibernation. However, bone formation concentrations in new mothers were significantly reduced compared to pre-hibernation concentrations. The de-coupling of bone turnover in favour of bone formation prior to hibernation, suggests that wild polar bears may posses a unique physiological mechanism for building bone in protective preparation against expected osteopenia associated with disuse, starvation, and hormonal drives to mobilise calcium for reproduction, during hibernation. Understanding this physiological mechanism could have profound implications for a natural solution for the prevention of osteoporosis in animals subjected to captivity with inadequate space for exercise, humans subjected to prolonged bed rest while recovering from illness, or astronauts exposed to antigravity during spaceflight. Alanda R. Lennox and Allen E. Goodship |
author2 |
School of Medical Sciences : Pathology |
format |
Article in Journal/Newspaper |
author |
Lennox, Alanda R. Goodship, Allen Edward |
author_facet |
Lennox, Alanda R. Goodship, Allen Edward |
author_sort |
Lennox, Alanda R. |
title |
Polar bears (Ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation |
title_short |
Polar bears (Ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation |
title_full |
Polar bears (Ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation |
title_fullStr |
Polar bears (Ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation |
title_full_unstemmed |
Polar bears (Ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation |
title_sort |
polar bears (ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation |
publisher |
Elsevier Science |
publishDate |
2008 |
url |
http://hdl.handle.net/2440/53736 https://doi.org/10.1016/j.cbpa.2007.11.012 |
genre |
polar bear Ursus maritimus |
genre_facet |
polar bear Ursus maritimus |
op_relation |
Comparative Biochemistry and Physiology A-Molecular and Integrative Physiology, 2008; 149:203-208 1095-6433 http://hdl.handle.net/2440/53736 doi:10.1016/j.cbpa.2007.11.012 |
op_doi |
https://doi.org/10.1016/j.cbpa.2007.11.012 |
container_title |
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology |
container_volume |
149 |
container_issue |
2 |
container_start_page |
203 |
op_container_end_page |
208 |
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1766171294833836032 |