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Gao X, Wang S, Shen S, Wang S, Xie M, Storey KB, Yu C, Lefai E, Song W, Chang H, Yang C. Differential bone remodeling mechanism in hindlimb unloaded and hibernating Daurian ground squirrels: a comparison between artificial and natural disuse within the same species. J Comp Physiol B 2023; 193:329-350. [PMID: 36988658 DOI: 10.1007/s00360-023-01482-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 02/06/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023]
Abstract
Loss of bone mass can occur in mammals after prolonged disuse but the situation for hibernators that are in a state of torpor for many months of the year is not yet fully understood. The present study assesses the bone remodeling mechanisms present in Daurian ground squirrels (Spermophilus dauricus) during hibernation as compared with a model of hindlimb disuse. Differences in microstructure, mechanical properties, bone remodeling-related proteins (Runx2, OCN, ALP, RANKL, CTK and MMP-9) and key proteins of Wnt/β-catenin signaling pathway (GSK-3β and phospho-β-catenin) were evaluated in ground squirrels under 3 conditions: summer active (SA) vs. hibernation (HIB) vs. hindlimb unloaded (HLU). The results indicated that the body weight in HLU ground squirrels was lower than the SA group, and the middle tibia diameter in the HLU group was lower than that in SA and HIB groups. The thickness of cortical and trabecular bone in femurs from HLU ground squirrels was lower than in SA and HIB groups. Most parameters of the tibia in the HLU group were lower than those in SA and HIB groups, which indicated cortical bone loss in ground squirrels. Moreover, our data showed that the changes in microscopic parameters in the femur were more obvious than those in the tibia in HLU and HIB ground squirrels. The levels of Runx2 and ALP were lower in HLU ground squirrels than SA and HIB groups. The protein levels of OCN were unchanged in the three groups, but the protein levels of ALP were lower in the HLU group than in SA and HIB groups. RANKL, CTK and MMP-9 protein levels were significantly decreased in tibia of HLU ground squirrels as compared with SA and HIB groups. In addition, the protein expression levels of RANKL, CTK and MMP-9 showed no statistical difference between SA and HIB ground squirrels. Thus, the mechanisms involved in the balance between bone formation and resorption in hibernating and hindlimb unloading ground squirrels may be different. The present study showed that in femur, the Wnt signaling pathway was inhibited, the protein level of GSK-3β was increased, and the protein expression of phospho-β-catenin was decreased in the HIB group as compared with the SA group, which indicates that the Wnt signaling pathway has a great influence on the femur of the HIB group. In conclusion, the natural anti-osteoporosis properties of Daurian ground squirrels are seasonal. The squirrels do not experience bone loss when they are inactive for a long time during hibernation, but the mechanisms of anti-osteoporosis did not work in HLU summer active squirrels.
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Affiliation(s)
- Xuli Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Siqi Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Siqi Shen
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Shuyao Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Manjiang Xie
- Department of Aerospace Physiology, Key Laboratory of Aerospace Medicine of Ministry of Education, Air Force Medical University, Xi'an, 710032, China
| | - Kenneth B Storey
- Department of Biology, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Caiyong Yu
- Military Medical Innovation Center, Air Force Medical University, Xi'an, 710032, Shaanxi, China
| | - Etienne Lefai
- INRAE, Unité de Nutrition Humaine, UMR 1019, Université Clermont Auvergne, 63000, Clermont-Ferrand, France
| | - Wenqian Song
- Northwest University Hospital, Xi'an, 710069, People's Republic of China
| | - Hui Chang
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China.
| | - Changbin Yang
- Military Medical Innovation Center, Air Force Medical University, Xi'an, 710032, Shaanxi, China.
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Bone adaptation and osteoporosis prevention in hibernating mammals. Comp Biochem Physiol A Mol Integr Physiol 2023; 280:111411. [PMID: 36871815 DOI: 10.1016/j.cbpa.2023.111411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023]
Abstract
Hibernating bears and rodents have evolved mechanisms to prevent disuse osteoporosis during the prolonged physical inactivity that occurs during hibernation. Serum markers and histological indices of bone remodeling in bears indicate reduced bone turnover during hibernation, which is consistent with organismal energy conservation. Calcium homeostasis is maintained by balanced bone resorption and formation since hibernating bears do not eat, drink, urinate, or defecate. Reduced and balanced bone remodeling protect bear bone structure and strength during hibernation, unlike the disuse osteoporosis that occurs in humans and other animals during prolonged physical inactivity. Conversely, some hibernating rodents show varying degrees of bone loss such as osteocytic osteolysis, trabecular loss, and cortical thinning. However, no negative effects of hibernation on bone strength in rodents have been found. More than 5000 genes in bear bone tissue are differentially expressed during hibernation, highlighting the complexity of hibernation induced changes in bone. A complete picture of the mechanisms that regulate bone metabolism in hibernators still alludes us, but existing data suggest a role for endocrine and paracrine factors such as cocaine- and amphetamine-regulated transcript (CART) and endocannabinoid ligands like 2-arachidonoyl glycerol (2-AG) in decreasing bone remodeling during hibernation. Hibernating bears and rodents evolved the capacity to preserve bone strength during long periods of physical inactivity, which contributes to their survival and propagation by allowing physically activity (foraging, escaping predators, and mating) without risk of bone fracture following hibernation. Understanding the biological mechanisms regulating bone metabolism in hibernators may inform novel treatment strategies for osteoporosis in humans.
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Nagy E, Sobh MM, Abdalbary M, Elnagar S, Elrefaey R, Shabaka S, Elshabrawy N, Shemies R, Tawfik M, Santos CGS, Barreto FC, El-Husseini A. Is Adynamic Bone Always a Disease? Lessons from Patients with Chronic Kidney Disease. J Clin Med 2022; 11:jcm11237130. [PMID: 36498703 PMCID: PMC9736225 DOI: 10.3390/jcm11237130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022] Open
Abstract
Renal osteodystrophy (ROD) is a common complication of end-stage kidney disease that often starts early with loss of kidney function, and it is considered an integral part in management of patients with chronic kidney disease (CKD). Adynamic bone (ADB) is characterized by suppressed bone formation, low cellularity, and thin osteoid seams. There is accumulating evidence supporting increasing prevalence of ADB, particularly in early CKD. Contemporarily, it is not very clear whether it represents a true disease, an adaptive mechanism to prevent bone resorption, or just a transitional stage. Several co-players are incriminated in its pathogenesis, such as age, diabetes mellitus, malnutrition, uremic milieu, and iatrogenic factors. In the present review, we will discuss the up-to-date knowledge of the ADB and focus on its impact on bone health, fracture risk, vascular calcification, and long-term survival. Moreover, we will emphasize the proper preventive and management strategies of ADB that are pivotal issues in managing patients with CKD. It is still unclear whether ADB is always a pathologic condition or whether it can represent an adaptive process to suppress bone resorption and further bone loss. In this article, we tried to discuss this hard topic based on the available limited information in patients with CKD. More studies are needed to be able to clearly address this frequent ROD finding.
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Affiliation(s)
- Eman Nagy
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Mahmoud M. Sobh
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Mohamed Abdalbary
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Sherouk Elnagar
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Rabab Elrefaey
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Shimaa Shabaka
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Nehal Elshabrawy
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Rasha Shemies
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Mona Tawfik
- Mansoura Nephrology and Dialysis Unit, Mansoura University, Mansoura 35516, Egypt
| | - Cássia Gomes S. Santos
- Department of Internal Medicine, Division of Nephrology, Federal University of Paraná, Curitiba 80060-00, PR, Brazil
| | - Fellype C. Barreto
- Department of Internal Medicine, Division of Nephrology, Federal University of Paraná, Curitiba 80060-00, PR, Brazil
| | - Amr El-Husseini
- Division of Nephrology & Bone and Mineral Metabolism, University of Kentucky, Lexington, KY 40536-0298, USA
- Correspondence: ; Tel.: +1-859-218-0934; Fax: +1-859-323-0232
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Babosová R, Zedda M, Belica A, Golej M, Chovancová G, Kalaš M, Vondráková M. The enrichment of knowledge about the microstructure of brown bear compact bone tissue. THE EUROPEAN ZOOLOGICAL JOURNAL 2022. [DOI: 10.1080/24750263.2022.2068682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- R. Babosová
- Department of Zoology and Anthropology, Constantine the Philosopher University in Nitra, Nitra, Slovakia
| | - M. Zedda
- Department of Veterinary Medicine, University of Sassari, Sassari, Italy
| | - A. Belica
- Department of Zoology and Anthropology, Constantine the Philosopher University in Nitra, Nitra, Slovakia
| | - M. Golej
- Earth Science Institute, Slovak Academy of Sciences, Bratislava, Slovakia
| | - G. Chovancová
- TANAP State Forests, Vysoké Tatry – Tatranská Lomnica, Slovakia
| | - M. Kalaš
- Administration of the Malá Fatra National Park, Varín, Slovakia
| | - M. Vondráková
- Department of Zoology and Anthropology, Constantine the Philosopher University in Nitra, Nitra, Slovakia
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Yin R, Zhang J, Xu S, Kong Y, Wang H, Gao Y. Resistance to disuse-induced iron overload in Daurian ground squirrels (Spermophilus dauricus) during extended hibernation inactivity. Comp Biochem Physiol B Biochem Mol Biol 2021; 257:110650. [PMID: 34298179 DOI: 10.1016/j.cbpb.2021.110650] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/15/2021] [Accepted: 07/18/2021] [Indexed: 11/30/2022]
Abstract
Iron overload occurs in disuse-induced osteoporosis. Hibernators are a natural animal model of resistance to disuse osteoporosis. We hypothesized that hibernators avoid iron overload to resist disuse-induced osteoporosis. Here, the role of iron metabolism in resistance to disuse osteoporosis was investigated by studying differences in iron content and iron metabolism in the femurs and livers of Daurian ground squirrels (Spermophilus dauricus) between the summer active and torpid states. Results showed that the femurs were generally well-maintained during torpor, with no significant differences observed in most bone microstructural parameters, except for a significantly lower (by 40%) trabecular bone connection density. Femur and liver iron concentrations were significantly lower during torpor (by 59% and 49%, respectively). Based on histological staining, livers were iron-negative and femurs showed a reduction in iron-positive area (by 83%) during torpor; The number of osteoblasts and osteoclasts showed no significant differences between the two groups. Most iron metabolism/homeostasis proteins expression levels in the femur and liver showed no significant differences between the two groups, with their stable expression likely preventing iron overload during inactivity. Higher femoral transferrin receptor 1 (TfR1) expression (by 108%) and lower liver ferritin expression (by 45%) were found in torpid squirrels. Lower liver ferritin may be related to the lower iron content, with the elevation in femoral TfR1 potentially related to restoration of bone iron levels. In conclusion, despite long periods of inactivity, iron levels in the femur and liver of squirrels were lower, bone formation and resorption were balanced and no iron overload was observed, as is found under disuse conditions in non-hibernators. Therefore, avoiding iron overload may be a potential mechanism for hibernators to avoid disuse-induced bone loss.
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Affiliation(s)
- Rongrong Yin
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 710069, China
| | - Jie Zhang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 710069, China
| | - Shenhui Xu
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 710069, China
| | - Yong Kong
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 710069, China
| | - Huiping Wang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 710069, China.
| | - Yunfang Gao
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 710069, China.
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Differentiating the causes of adynamic bone in advanced chronic kidney disease informs osteoporosis treatment. Kidney Int 2021; 100:546-558. [PMID: 34102219 DOI: 10.1016/j.kint.2021.04.043] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 04/15/2021] [Accepted: 04/20/2021] [Indexed: 12/15/2022]
Abstract
Patients with chronic kidney disease (CKD) have an increased fracture risk because of impaired bone quality and quantity. Low bone mineral density predicts fracture risk in all CKD stages, including advanced CKD (CKD G4-5D). Pharmacological therapy improves bone mineral density and reduces fracture risk in moderate CKD. Its efficacy in advanced CKD remains to be determined, although pilot studies suggest a positive effect on bone mineral density. Currently, antiresorptive agents are the most commonly prescribed drugs for the prevention and therapy of osteoporosis. Their use in advanced CKD has been limited by the lack of large clinical trials and fear of causing kidney dysfunction and adynamic bone disease. In recent decades, adynamic bone disease has evolved as the most predominant form of renal osteodystrophy, commonly associated with poor outcomes, including premature mortality and progression of vascular calcification. Evolving evidence indicates that reduction of bone turnover by parathyroidectomy or pharmacological therapies, such as calcimimetics and antiresorptive agents, are not associated with premature mortality or accelerated vascular calcification in CKD. In contrast, chronic inflammation, oxidative stress, malnutrition, and diabetes can induce low bone turnover and associate with poor prognosis. Thus, the conditions causing suppression of bone turnover rather than the low bone turnover per se may account for the perceived association with outcomes. Anabolic treatment, in contrast, has been suggested to improve turnover and bone mass in patients with advanced CKD and low bone turnover; however, uncertainty about safety even exceeds that of antiresorptive agents. Here, we critically review the pathophysiological concept of adynamic bone disease and discuss the effect of low bone turnover on the safety and efficacy of anti-osteoporosis pharmacotherapy in advanced CKD.
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Gao X, Wang S, Zhang J, Wang S, Bai F, Liang J, Wu J, Wang H, Gao Y, Chang H. Differential bone remodeling mechanism in hindlimb unloaded rats and hibernating Daurian ground squirrels: a comparison between artificial and natural disuse. J Comp Physiol B 2021; 191:793-814. [PMID: 34002279 DOI: 10.1007/s00360-021-01375-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 04/02/2021] [Accepted: 04/20/2021] [Indexed: 11/30/2022]
Abstract
To determine that differential bone remodeling mechanism (especially Wnt signaling) in hindlimb unloaded rats and hibernating Daurian ground squirrels, the bone microstructure, mechanical properties, and expression levels of bone remodeling related proteins and key proteins of Wnt/β-catenin signaling were analyzed in this study. The thickness of cortical and trabecular bone was decreased in femur of hindlimb unloaded rats, while it was maintained in femur of hibernating ground squirrels. Interestingly, the ultimate bending energy and ultimate normalized displacement were reduced and the bending rigidity was increased in tibia of hibernating ground squirrels. Besides, the protein level of Runx2 was decreased in femur and tibia of unloaded rats, while it was maintained in tibia and even increased in femur of hibernating ground squirrels. The protein levels of RANKL and MMP-9 were increased in femur and tibia in unloaded rats, while they were maintained in both femur and tibia of hibernating ground squirrels. The protein level of GSK-3β was increased in femur and tibia of unloaded rats, while it was maintained in both femur and tibia of hibernating ground squirrels. The phospho-β-catenin expression was increased in both femur and tibia of unloaded rats, while it was only decreased in femur, but maintained in tibia of hibernating ground squirrels. In conclusion, the femur and tibia in hindlimb unloaded rats showed obvious bone loss, while they mitigated disuse-induced bone loss in hibernating ground squirrels, involving differential protein expression of key molecules in bone remodeling. In comparison with hindlimb unloaded rats, promoting osteoblast differentiation through activating canonical GSK-3β/β-catenin signaling involving Runx2 might be an adaptation to natural disuse in femur of hibernating Daurian ground squirrels. However, there was no statistical change in the protein levels of bone formation related proteins, GSK-3β and phospho-β-catenin in tibia of hibernating Daurian ground squirrels.
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Affiliation(s)
- Xuli Gao
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, 710069, People's Republic of China.,Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Siqi Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Jie Zhang
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, 710069, People's Republic of China.,Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Shuyao Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Feiyan Bai
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Jing Liang
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Jiawei Wu
- Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Huiping Wang
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, 710069, People's Republic of China.,Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China
| | - Yunfang Gao
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, 710069, People's Republic of China. .,Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China.
| | - Hui Chang
- Shaanxi Key Laboratory for Animal Conservation, Northwest University, Xi'an, 710069, People's Republic of China. .,Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, 229# North Taibai Road, Xi'an, 710069, People's Republic of China.
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8
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Transcriptional changes and preservation of bone mass in hibernating black bears. Sci Rep 2021; 11:8281. [PMID: 33859306 PMCID: PMC8050052 DOI: 10.1038/s41598-021-87785-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/05/2021] [Indexed: 11/19/2022] Open
Abstract
Physical inactivity leads to losses of bone mass and strength in most mammalian species. In contrast, hibernating bears show no bone loss over the prolonged periods (4–6 months) of immobility during winter, which suggests that they have adaptive mechanisms to preserve bone mass. To identify transcriptional changes that underlie molecular mechanisms preventing disuse osteoporosis, we conducted a large-scale gene expression screening in the trabecular bone and bone marrow, comparing hibernating and summer active bears through sequencing of the transcriptome. Gene set enrichment analysis showed a coordinated down-regulation of genes involved in bone resorption, osteoclast differentiation and signaling, and apoptosis during hibernation. These findings are consistent with previous histological findings and likely contribute to the preservation of bone during the immobility of hibernation. In contrast, no significant enrichment indicating directional changes in gene expression was detected in the gene sets of bone formation and osteoblast signaling in hibernating bears. Additionally, we revealed significant and coordinated transcriptional induction of gene sets involved in aerobic energy production including fatty acid beta oxidation, tricarboxylic acid cycle, oxidative phosphorylation, and mitochondrial metabolism. Mitochondrial oxidation was likely up-regulated by transcriptionally induced AMPK/PGC1α pathway, an upstream stimulator of mitochondrial function.
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Donahue SW, Wojda SJ, McGee-Lawrence ME, Auger J, Black HL. Osteoporosis prevention in an extraordinary hibernating bear. Bone 2021; 145:115845. [PMID: 33450432 DOI: 10.1016/j.bone.2021.115845] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 11/20/2022]
Abstract
Disuse osteoporosis results from physical inactivity. Reduced mechanical loading of bone stimulates bone resorption leading to bone loss, decreased mechanical properties, and increased fracture risk. Compensatory mechanisms evolved in hibernators to preserve skeletal muscle and bone during the prolonged physical inactivity that occurs during annual hibernation. This paper reports the preservation of bone properties in an exceptionally old black bear that was physically inactive for about 6 months annually for 31 years. The biological mechanisms that preserve bone during prolonged disuse during hibernation are also reviewed.
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Affiliation(s)
- Seth W Donahue
- Department of Biomedical Engineering, University of Massachusetts, Amherst, United States of America.
| | - Samantha J Wojda
- Department of Biomedical Engineering, University of Massachusetts, Amherst, United States of America
| | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Department of Orthopaedic Surgery, Medical College of Georgia, Augusta University, United States of America
| | - Janene Auger
- Monte L. Bean Life Science Museum, Brigham Young University, United States of America
| | - Hal L Black
- Department of Plant and Wildlife Sciences, Brigham Young University, United States of America
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Zhang J, Chang H, Yin R, Xu S, Wang H, Gao Y. A temporal study on musculoskeletal morphology and metabolism in hibernating Daurian ground squirrels (Spermophilus dauricus). Bone 2021; 144:115826. [PMID: 33348129 DOI: 10.1016/j.bone.2020.115826] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 12/14/2022]
Abstract
Hibernators provide a natural model to study the mechanisms underlying the prevention of disuse-induced musculoskeletal deterioration. Currently, however, these mechanisms remain poorly understood. Here, we investigated changes in morphology and metabolic indices in the hindlimb skeletal muscle and bone of Daurian ground squirrels (Spermophilus dauricus) during different periods of hibernation, and further explored the possible mechanisms involved in the musculoskeletal maintenance of hibernators after prolonged inactivity. Results showed that, compared with levels in the summer active group (SA), almost all morphological indices of skeletal muscle and bone, including muscle mass, muscle fiber cross-sectional area, bone mass, bone length, and bone mechanical properties, were unchanged in the different periods of hibernation. Only a few microstructural parameters of bone showed deterioration in the post-hibernation group (POST), including increased specific bone surface (+71%), decreased trabecular thickness (-43%), and decreased average cortical thickness (-51%) in the tibia, and increased trabecular separation (+60%) in the femur. Furthermore, most examined metabolic indices involved in muscle protein turnover and bone remodeling were unchanged, except for several indices in the inter-bout arousal group (IBA), i.e., increase in the phosphorylation of eukaryotic initiation factor 4E binding protein 1 (4E-BP1) (IBA vs. SA, +80%) in the vastus medialis muscle, increase in chymotrypsin-like activity (IBA vs. SA, +62%) in the tibialis anterior muscle, increase in osteoblast number (IBA vs. SA, +110%; IBA vs. torpor (TOR), +68%) and osteoclast number (IBA vs. TOR, +105%) per bone surface in the tibia, and increase in osteoclast surface per bone surface (IBA vs. TOR, +128%) in the femur. The above evidence demonstrates that the musculoskeletal morphology of squirrels was largely preserved, and musculoskeletal metabolism was generally maintained after prolonged hibernation inactivity. These findings suggest that the well-maintained musculoskeletal metabolism may be a vital mechanism underlying the preservation of the musculoskeletal system during hibernation. The coincident up-regulation of several metabolic indicators during IBA indicates that musculoskeletal metabolism may be relatively active during this period; however, its role in musculoskeletal maintenance during hibernation needs further clarification.
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Affiliation(s)
- Jie Zhang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, Xi'an 710069, China
| | - Hui Chang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, Xi'an 710069, China
| | - Rongrong Yin
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, Xi'an 710069, China
| | - Shenhui Xu
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, Xi'an 710069, China
| | - Huiping Wang
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, Xi'an 710069, China
| | - Yunfang Gao
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China; Key Laboratory of Resource Biology and Biotechnology in Western China, College of Life Sciences, Northwest University, Ministry of Education, Xi'an 710069, China.
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11
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Nishida K, Shimozuru M, Okamatsu-Ogura Y, Miyazaki M, Soma T, Sashika M, Tsubota T. Changes in liver microRNA expression and their possible regulatory role in energy metabolism-related genes in hibernating black bears. J Comp Physiol B 2021; 191:397-409. [PMID: 33459845 DOI: 10.1007/s00360-020-01337-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 12/22/2020] [Accepted: 12/30/2020] [Indexed: 01/12/2023]
Abstract
Hibernating bears survive up to 6 months without feeding while yet maintaining metabolic homeostasis. We previously reported expression changes in energy metabolism-related genes in the liver of hibernating Japanese black bears. The present study examined the role of microRNAs in the regulation of hepatic gene expression during hibernation. The quantitative analyses revealed significant increases in the expression of 4 microRNAs (miR-221-3p, miR-222-3p, miR-455-3p, and miR-195a-5p) and decreases of 2 microRNAs (miR-122-5p and miR-7a-1-5p) during hibernation. RNA sequencing and in silico target prediction regarding 3 upregulated microRNAs (miR-221-3p, miR-222-3p and miR-455-3p) found 13 target mRNAs with significantly decreased expression during hibernation. The transfection of microRNA mimics into cells showed that miR-222 and miR-455 reduced solute carrier family 16 member 4 (SLC16A4) and fatty acid synthase (FASN) mRNA expression, respectively. Our results suggest that the increased levels of hepatic miRNA during hibernation (miR-222-3p and miR-455-3p) negatively regulate the expression of targeted genes predicted to be involved in the transport of energy source and de novo fatty acid synthesis, is consistent with a regulatory role of these miRNAs in energy metabolism in hibernating black bears.
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Affiliation(s)
- Kazuhei Nishida
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Kita-ku, Sapporo, Hokkaido, 060-0818, Japan
| | - Michito Shimozuru
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Kita-ku, Sapporo, Hokkaido, 060-0818, Japan.
| | - Yuko Okamatsu-Ogura
- Laboratory of Biochemistry, Faculty of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Kita-ku, Sapporo, Hokkaido, 060-0818, Japan
| | - Mitsunori Miyazaki
- Department of Physical Therapy, School of Rehabilitation Sciences, Health Sciences University of Hokkaido, Hokkaido, 061-0293, Japan
| | - Tsukasa Soma
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Kita-ku, Sapporo, Hokkaido, 060-0818, Japan
| | - Mariko Sashika
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Kita-ku, Sapporo, Hokkaido, 060-0818, Japan
| | - Toshio Tsubota
- Laboratory of Wildlife Biology and Medicine, Faculty of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Kita-ku, Sapporo, Hokkaido, 060-0818, Japan
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12
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Walker EC, McGregor NE, Chan ASM, Sims NA. Measuring Bone Volume at Multiple Densities by Micro-computed Tomography. Bio Protoc 2021; 11:e3873. [PMID: 33732762 PMCID: PMC7953249 DOI: 10.21769/bioprotoc.3873] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/26/2020] [Accepted: 11/24/2020] [Indexed: 11/02/2022] Open
Abstract
Bone strength is controlled by both bone mass, and the organization and quality of the bone material. The current standard method for measuring bone mass in mouse and rat studies is micro-computed tomography. This method typically uses a single threshold to identify bone material in the cortical and trabecular regions. However, this single threshold method obscures information about the mineral content of the bone material and depends on normal morphology to separately analyze cortical and trabecular structures. To extend this method to identify bone mass at multiple density levels, we have established a protocol for unbiased selection and application of multiple thresholds using a standard laboratory-based micro-computed tomography instrument. This non-invasive method can be applied to longitudinal studies and archived samples and provides additional information about bone structure and strength.
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Affiliation(s)
- Emma C. Walker
- Bone Cell Biology and Disease Unit, St. Vincent’s Institute of Medical Research, Melbourne, Australia
| | - Narelle E. McGregor
- Bone Cell Biology and Disease Unit, St. Vincent’s Institute of Medical Research, Melbourne, Australia
| | - Audrey S. M. Chan
- Centre for Muscle Research, The University of Melbourne, Melbourne, Australia
| | - Natalie A. Sims
- Bone Cell Biology and Disease Unit, St. Vincent’s Institute of Medical Research, Melbourne, Australia
- Melbourne Medical School, The University of Melbourne, Melbourne, Australia
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13
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Nasoori A, Okamatsu-Ogura Y, Shimozuru M, Sashika M, Tsubota T. Hibernating bear serum hinders osteoclastogenesis in-vitro. PLoS One 2020; 15:e0238132. [PMID: 32853221 PMCID: PMC7451522 DOI: 10.1371/journal.pone.0238132] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/10/2020] [Indexed: 01/17/2023] Open
Abstract
Bears do not suffer from osteoporosis during hibernation, which is associated with long-term inactivity, lack of food intake, and cold exposure. However, the mechanisms involved in bone loss prevention have scarcely been elucidated in bears. We investigated the effect of serum from hibernating Japanese black bears (Ursus thibetanus japonicus) on differentiation of peripheral blood mononuclear cells (PBMCs) to osteoclasts (OCs). PBMCs collected from 3 bears were separately cultured with 10% serum of 4 active and 4 hibernating bears (each individual serum type was assessed separately by a bear PBMCs), and differentiation were induced by treatment with macrophage colony stimulating factor (M-CSF) and receptor activator of NF-kB ligand (RANKL). PBMCs that were cultured with the active bear serum containing medium (ABSM) differentiated to multi-nucleated OCs, and were positive for TRAP stain. However, cells supplemented with hibernating bear serum containing medium (HBSM) failed to form OCs, and showed significantly lower TRAP stain (p < 0.001). On the other hand, HBSM induced proliferation of adipose derived mesenchymal stem cells (ADSCs) similarly to ABSM (p > 0.05), indicating no difference on cell growth. It was revealed that osteoclastogenesis of PBMCs is hindered by HBSM, implying an underlying mechanism for the suppressed bone resorption during hibernation in bears. In addition, this study for the first time showed the formation of bears’ OCs in-vitro.
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Affiliation(s)
- Alireza Nasoori
- Laboratory of Wildlife Biology and Medicine, Department of Environmental Veterinary Science, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Yuko Okamatsu-Ogura
- Laboratory of Biochemistry, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Michito Shimozuru
- Laboratory of Wildlife Biology and Medicine, Department of Environmental Veterinary Science, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Mariko Sashika
- Laboratory of Wildlife Biology and Medicine, Department of Environmental Veterinary Science, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Toshio Tsubota
- Laboratory of Wildlife Biology and Medicine, Department of Environmental Veterinary Science, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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14
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Huang Y, Chen H, Yang P, Bai X, Shi Y, Vistro WA, Tarique I, Haseeb A, Chen Q. Hepatic lipid droplet breakdown through lipolysis during hibernation in Chinese Soft-Shelled Turtle ( Pelodiscus sinensis). Aging (Albany NY) 2020; 11:1990-2002. [PMID: 30926766 PMCID: PMC6503876 DOI: 10.18632/aging.101887] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/20/2019] [Indexed: 12/12/2022]
Abstract
Hibernation is an adaptive survival strategy in response to cold and foodless winter. To determine the underlying mechanisms of seasonal adaptions, transcriptome sequencing studies have been conducted in bears, ground squirrels and bats. Despite advances in identifying differentially expressed genes involved in metabolism, the precise mechanisms of these physiological adaptions remain unclear. In the present study, we examined liver of Chinese Soft-Shelled Turtle (Pelodiscus sinensis) and found that the contents of lipid droplet (LD) and triglyceride (TG) were significantly decreased during hibernation. Increases in mRNA expression levels of lipolysis-related genes and decreased levels of lipogenesis-related genes during hibernation indicated that LD hydrolysis was stimulated during hibernation. To continuously release fatty acids (FAs) from LD, adipose triglyceride lipase (ATGL) was recruited and accumulated on the surface of LDs via activation of Cyclic Adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling. Meanwhile, increased phosphorylation of the LD-associated protein, perilipin-5, activated the enzyme activity of ATGL via interaction between comparative gene identification-58 (CGI-58) and ATGL. Taken together, our results indicated that ATGL accumulation on the LD surface and its induced enzyme activity during hibernation promoted LD breakdown in the liver of Chinese Soft-Shelled Turtle (Pelodiscus sinensis), thereby enhancing mitochondrial β-oxidation to maintain energy hemostasis.
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Affiliation(s)
- Yufei Huang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
| | - Hong Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
| | - Ping Yang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
| | - Xuebing Bai
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
| | - Yonghong Shi
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China.,Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Waseem Ali Vistro
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
| | - Imran Tarique
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
| | - Abdul Haseeb
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
| | - Qiusheng Chen
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province 210095, China
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15
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Arfat Y, Rani A, Jingping W, Hocart CH. Calcium homeostasis during hibernation and in mechanical environments disrupting calcium homeostasis. J Comp Physiol B 2020; 190:1-16. [DOI: 10.1007/s00360-019-01255-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/21/2019] [Accepted: 12/16/2019] [Indexed: 12/22/2022]
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16
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Chen YC, Aui SP, Lai YS, Chang KT. Adult Stem Cells in Hibernation: Future Perspectives of Space Travel. Int J Stem Cells 2019; 12:381-387. [PMID: 31474026 PMCID: PMC6881040 DOI: 10.15283/ijsc19048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/20/2019] [Accepted: 07/05/2019] [Indexed: 11/09/2022] Open
Abstract
Space traveling is imperative for mankind in the future. Expectedly, hibernation will become an option for space traveler to overcome the endless voyage. With regard to some of the studies pointed out that during hibernation, muscle will undergo atrophy and meantime neurogenesis will reduce, these obstacles were frequently related with stem cell regeneration. Thus, investigation on whether hibernation will lead to dysfunction of stem cell becomes an important issue. By going through four main systems in this article, such as, hematopoietic system, skeletal muscle system, central nervous system and orthopedic system, we are expecting that stem cells regeneration capacity will be affected by hibernation. To date, these researches are majorly the read-out from short term or seasonal hibernating mammals. Proposing and creating a simulated long-term hibernation animal model is turning essential for the further investigation on the effect of longer period of hibernation to human stem cells.
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Affiliation(s)
- Yu-Chih Chen
- Graduate Institute of Bioresources, National Pingtung University of Science and Technology, Neipu, Taiwan
| | - Shin-Peir Aui
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, Neipu, Taiwan
| | - Yin-Siew Lai
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, Neipu, Taiwan.,Flow Cytometry Center, Precision Instruments Center, National Pingtung University of Science and Technology, Neipu, Taiwan.,Research Center for Animal Biologics, National Pingtung University of Science and Technology, Neipu, Taiwan
| | - Ko-Tung Chang
- Department of Biological Science and Technology, National Pingtung University of Science and Technology, Neipu, Taiwan.,Flow Cytometry Center, Precision Instruments Center, National Pingtung University of Science and Technology, Neipu, Taiwan.,Research Center for Animal Biologics, National Pingtung University of Science and Technology, Neipu, Taiwan
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17
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Cravens EM, Kirkwood JS, Wolfe LM, Packer RA, Whalen LR, Wojda SJ, Prenni JE, Florant GL, Donahue SW. The effects of neurectomy and hibernation on bone properties and the endocannabinoid system in marmots (Marmota flaviventris). Comp Biochem Physiol A Mol Integr Physiol 2019; 241:110621. [PMID: 31783174 DOI: 10.1016/j.cbpa.2019.110621] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 10/15/2019] [Accepted: 11/21/2019] [Indexed: 01/26/2023]
Abstract
Hibernators have adapted a physiological mechanism allowing them to undergo long periods of inactivity without experiencing bone loss. However, the biological mechanisms that prevent bone loss are unknown. Previous studies found meaningful changes, between active and hibernating marmots, in the endocannabinoid system of many tissues, including bone. Cannabinoid receptors (CB1 and CB2) have divergent localization in bone. CB1 is predominately found on sympathetic nerve terminals, while CB2 is more abundant on bone cells and their progenitors. This study aimed to determine the contribution of innervation on endocannabinoid regulation of bone properties in hibernating (during torpor) and non-hibernating yellow-bellied marmots. Neurectomy, a model for disuse osteoporosis, was performed unilaterally in both hibernating and active marmots. Endocannabinoid concentrations were measured in bone marrow, cortical, and trabecular regions from fourth metatarsals of both hindlimbs using microflow chromatography-tandem quadrupole mass spectrometry. Trabecular bone architectural properties of fifth metatarsals were evaluated using micro-computed tomography. There were ligand-specific increases with neurectomy in active, but not hibernating, marmots. Trabecular bone architectural properties were not affected by neurectomy during hibernation, but did show some minor negative changes in active marmots. These findings suggest protection from bone loss in hibernating rodents is peripherally rather than centrally regulated. Furthermore, findings suggest even active marmots with normal metabolism are partially protected from disuse induced bone loss compared to laboratory rodents. Understanding the mechanism hibernators use to maintain bone density may guide development for novel bone loss prevention therapies.
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Affiliation(s)
- Emily M Cravens
- School of Bioengineering, Colorado State University, Fort Collins, CO, USA
| | - Jay S Kirkwood
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, USA
| | - Lisa M Wolfe
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, USA
| | - Rebecca A Packer
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Lawrence R Whalen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Samantha J Wojda
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Jessica E Prenni
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, USA
| | - Gregory L Florant
- Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Seth W Donahue
- School of Bioengineering, Colorado State University, Fort Collins, CO, USA.
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18
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Hibernating astronauts-science or fiction? Pflugers Arch 2018; 471:819-828. [PMID: 30569200 PMCID: PMC6533228 DOI: 10.1007/s00424-018-2244-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/29/2018] [Accepted: 12/03/2018] [Indexed: 12/13/2022]
Abstract
For long-duration manned space missions to Mars and beyond, reduction of astronaut metabolism by torpor, the metabolic state during hibernation of animals, would be a game changer: Water and food intake could be reduced by up to 75% and thus reducing payload of the spacecraft. Metabolic rate reduction in natural torpor is linked to profound changes in biochemical processes, i.e., shift from glycolysis to lipolysis and ketone utilization, intensive but reversible alterations in organs like the brain and kidney, and in heart rate control via Ca2+. This state would prevent degenerative processes due to organ disuse and increase resistance against radiation defects. Neuro-endocrine factors have been identified as main targets to induce torpor although the exact mechanisms are not known yet. The widespread occurrence of torpor in mammals and examples of human hypometabolic states support the idea of human torpor and its beneficial applications in medicine and space exploration.
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19
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Donahue SW. Krogh's principle for musculoskeletal physiology and pathology. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2018; 18:284-291. [PMID: 30179205 PMCID: PMC6146200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
August Krogh was a comparative physiologist who used frogs, guinea pigs, cats, dogs, and horses in his research that led to his Nobel Prize on muscle physiology. His idea to choose the most relevant organism to study problems in physiology has become known as Krogh's principle. Indeed, many important discoveries in physiology have been made using naturally occurring animal models. However, the majority of research today utilizes laboratory mouse and rat models to study problems in physiology. This paper discusses how Krogh's principle can be invoked in musculoskeletal research as a complementary approach to using standard laboratory rodent models for solving problems in musculoskeletal physiology. This approach may increase our ability to treat musculoskeletal diseases clinically. For example, it has been noted that progress in osteogenesis imperfecta research has been limited by the absence of a naturally occurring animal model. Several examples of naturally occurring animal models are discussed including osteoarthritis and osteosarcoma in dogs, resistance to disuse induced bone and skeletal muscle loss in mammalian hibernators, and bone phenotypic plasticity in fish lacking osteocytes. Many musculoskeletal diseases (e.g., osteoarthritis) occur naturally in companion animals, which may provide clues on etiology and progression of musculoskeletal diseases and accelerate the development of pharmaceutical therapies for humans.
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Affiliation(s)
- Seth W. Donahue
- Department of Biomedical Engineering, University of Massachusetts, USA,Corresponding author: Seth W. Donahue, Department of Biomedical Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA E-mail:
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20
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Jardim-Messeder D, Lambert K, Noctor S, Pestana FM, de Castro Leal ME, Bertelsen MF, Alagaili AN, Mohammad OB, Manger PR, Herculano-Houzel S. Dogs Have the Most Neurons, Though Not the Largest Brain: Trade-Off between Body Mass and Number of Neurons in the Cerebral Cortex of Large Carnivoran Species. Front Neuroanat 2017; 11:118. [PMID: 29311850 PMCID: PMC5733047 DOI: 10.3389/fnana.2017.00118] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/27/2017] [Indexed: 12/27/2022] Open
Abstract
Carnivorans are a diverse group of mammals that includes carnivorous, omnivorous and herbivorous, domesticated and wild species, with a large range of brain sizes. Carnivory is one of several factors expected to be cognitively demanding for carnivorans due to a requirement to outsmart larger prey. On the other hand, large carnivoran species have high hunting costs and unreliable feeding patterns, which, given the high metabolic cost of brain neurons, might put them at risk of metabolic constraints regarding how many brain neurons they can afford, especially in the cerebral cortex. For a given cortical size, do carnivoran species have more cortical neurons than the herbivorous species they prey upon? We find they do not; carnivorans (cat, mongoose, dog, hyena, lion) share with non-primates, including artiodactyls (the typical prey of large carnivorans), roughly the same relationship between cortical mass and number of neurons, which suggests that carnivorans are subject to the same evolutionary scaling rules as other non-primate clades. However, there are a few important exceptions. Carnivorans stand out in that the usual relationship between larger body, larger cortical mass and larger number of cortical neurons only applies to small and medium-sized species, and not beyond dogs: we find that the golden retriever dog has more cortical neurons than the striped hyena, African lion and even brown bear, even though the latter species have up to three times larger cortices than dogs. Remarkably, the brown bear cerebral cortex, the largest examined, only has as many neurons as the ten times smaller cat cerebral cortex, although it does have the expected ten times as many non-neuronal cells in the cerebral cortex compared to the cat. We also find that raccoons have dog-like numbers of neurons in their cat-sized brain, which makes them comparable to primates in neuronal density. Comparison of domestic and wild species suggests that the neuronal composition of carnivoran brains is not affected by domestication. Instead, large carnivorans appear to be particularly vulnerable to metabolic constraints that impose a trade-off between body size and number of cortical neurons.
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Affiliation(s)
- Débora Jardim-Messeder
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kelly Lambert
- Department of Psychology, University of Richmond, Richmond, VA, United States
| | - Stephen Noctor
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Fernanda M Pestana
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Mads F Bertelsen
- Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark
| | - Abdulaziz N Alagaili
- KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Osama B Mohammad
- KSU Mammals Research Chair, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Suzana Herculano-Houzel
- Department of Psychology, Vanderbilt University, Nashville, TN, United States.,Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
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21
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Mustonen AMJ, Finnilä MAJ, Puukka KS, Jämsä TJ, Saarakkala S, Tuukkanen JK, Nieminen TP. Raccoon dog model shows preservation of bone during prolonged catabolism and reduced physical activity. ACTA ACUST UNITED AC 2017; 220:2196-2202. [PMID: 28373598 DOI: 10.1242/jeb.135475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/27/2017] [Indexed: 11/20/2022]
Abstract
The raccoon dog (Nyctereutes procyonoides) is a promising animal model capable of preventing disuse-induced osteoporosis. Previous data suggest that this species resembles bears in the preservation of bone mass and biomechanical properties during prolonged passivity and catabolism. This longitudinal study examined the osteological properties of tibiae in farm-bred raccoon dogs that were either fed or fasted (n=6 per group) for a 10 week period. Peripheral quantitative computed tomography was utilized and plasma markers of bone turnover measured before fasting and at 9 weeks followed by mechanical testing (three-point bending), micro-computed tomography and Fourier transform infrared imaging at 10 weeks. Passive wintering with prolonged catabolism (body mass loss 32%) had no significant effects on bone mineralization, porosity or strength. The concentration of C-terminal telopeptide of type I collagen, indicative of bone resorption, increased in the plasma of the fasted raccoon dogs, while the bone formation markers were unchanged. The levels of 25-hydroxyvitamin D were reduced in the fasted animals. Based on these data, the preservation of bone in wintering raccoon dogs shares characteristics with that of bears with no apparent decrease in the formation of bone but increased resorption. To conclude, raccoon dogs were able to minimize bone loss during a 10 week period of catabolism and passivity.
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Affiliation(s)
- Anne-Mari J Mustonen
- University of Eastern Finland, Faculty of Health Sciences, School of Medicine, Institute of Biomedicine/Anatomy, PO Box 1627, Kuopio FI-70211, Finland .,University of Eastern Finland, Faculty of Science and Forestry, Department of Environmental and Biological Sciences, PO Box 111, Joensuu FI-80101, Finland
| | - Mikko A J Finnilä
- University of Oulu, Faculty of Medicine, Research Unit of Medical Imaging, Physics and Technology, PO Box 5000, Oulu FI-90014, Finland.,University of Eastern Finland, Faculty of Science and Forestry, Department of Applied Physics, PO Box 1627, Kuopio FI-70211, Finland.,Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 5000, Oulu FI-90014, Finland
| | - Katri S Puukka
- NordLab Oulu, Oulu University Hospital, PO Box 500, Oulu FI-90029, OYS, Finland.,University of Oulu, Faculty of Medicine, Department of Clinical Chemistry, PO Box 8000, Oulu FI-90014, Finland
| | - Timo J Jämsä
- University of Oulu, Faculty of Medicine, Research Unit of Medical Imaging, Physics and Technology, PO Box 5000, Oulu FI-90014, Finland.,Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 5000, Oulu FI-90014, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, PO Box 50, Oulu FI-90029, Finland
| | - Simo Saarakkala
- University of Oulu, Faculty of Medicine, Research Unit of Medical Imaging, Physics and Technology, PO Box 5000, Oulu FI-90014, Finland.,Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 5000, Oulu FI-90014, Finland.,Department of Diagnostic Radiology, Oulu University Hospital, PO Box 50, Oulu FI-90029, Finland
| | - Juha K Tuukkanen
- Medical Research Center Oulu, Oulu University Hospital and University of Oulu, PO Box 5000, Oulu FI-90014, Finland.,University of Oulu, Faculty of Medicine, Research Group of Cancer Research and Translational Medicine, PO Box 5000, Oulu FI-90014, Finland
| | - T Petteri Nieminen
- University of Eastern Finland, Faculty of Health Sciences, School of Medicine, Institute of Biomedicine/Anatomy, PO Box 1627, Kuopio FI-70211, Finland.,University of Eastern Finland, Faculty of Science and Forestry, Department of Environmental and Biological Sciences, PO Box 111, Joensuu FI-80101, Finland
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Laurent MR, Dubois V, Claessens F, Verschueren SMP, Vanderschueren D, Gielen E, Jardí F. Muscle-bone interactions: From experimental models to the clinic? A critical update. Mol Cell Endocrinol 2016; 432:14-36. [PMID: 26506009 DOI: 10.1016/j.mce.2015.10.017] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/13/2015] [Accepted: 10/20/2015] [Indexed: 02/06/2023]
Abstract
Bone is a biomechanical tissue shaped by forces from muscles and gravitation. Simultaneous bone and muscle decay and dysfunction (osteosarcopenia or sarco-osteoporosis) is seen in ageing, numerous clinical situations including after stroke or paralysis, in neuromuscular dystrophies, glucocorticoid excess, or in association with vitamin D, growth hormone/insulin like growth factor or sex steroid deficiency, as well as in spaceflight. Physical exercise may be beneficial in these situations, but further work is still needed to translate acceptable and effective biomechanical interventions like vibration therapy from animal models to humans. Novel antiresorptive and anabolic therapies are emerging for osteoporosis as well as drugs for sarcopenia, cancer cachexia or muscle wasting disorders, including antibodies against myostatin or activin receptor type IIA and IIB (e.g. bimagrumab). Ideally, increasing muscle mass would increase muscle strength and restore bone loss from disuse. However, the classical view that muscle is unidirectionally dominant over bone via mechanical loading is overly simplistic. Indeed, recent studies indicate a role for neuronal regulation of not only muscle but also bone metabolism, bone signaling pathways like receptor activator of nuclear factor kappa-B ligand (RANKL) implicated in muscle biology, myokines affecting bone and possible bone-to-muscle communication. Moreover, pharmacological strategies inducing isolated myocyte hypertrophy may not translate into increased muscle power because tendons, connective tissue, neurons and energy metabolism need to adapt as well. We aim here to critically review key musculoskeletal molecular pathways involved in mechanoregulation and their effect on the bone-muscle unit as a whole, as well as preclinical and emerging clinical evidence regarding the effects of sarcopenia therapies on osteoporosis and vice versa.
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Affiliation(s)
- Michaël R Laurent
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium.
| | - Vanessa Dubois
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Frank Claessens
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Sabine M P Verschueren
- Research Group for Musculoskeletal Rehabilitation, Department of Rehabilitation Science, KU Leuven, 3000 Leuven, Belgium
| | - Dirk Vanderschueren
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Evelien Gielen
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium; Centre for Metabolic Bone Diseases, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Ferran Jardí
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, 3000 Leuven, Belgium
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23
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Reilly BD, Franklin CE. Prevention of muscle wasting and osteoporosis: the value of examining novel animal models. J Exp Biol 2016; 219:2582-95. [DOI: 10.1242/jeb.128348] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
ABSTRACT
Bone mass and skeletal muscle mass are controlled by factors such as genetics, diet and nutrition, growth factors and mechanical stimuli. Whereas increased mechanical loading of the musculoskeletal system stimulates an increase in the mass and strength of skeletal muscle and bone, reduced mechanical loading and disuse rapidly promote a decrease in musculoskeletal mass, strength and ultimately performance (i.e. muscle atrophy and osteoporosis). In stark contrast to artificially immobilised laboratory mammals, animals that experience natural, prolonged bouts of disuse and reduced mechanical loading, such as hibernating mammals and aestivating frogs, consistently exhibit limited or no change in musculoskeletal performance. What factors modulate skeletal muscle and bone mass, and what physiological and molecular mechanisms protect against losses of muscle and bone during dormancy and following arousal? Understanding the events that occur in different organisms that undergo natural periods of prolonged disuse and suffer negligible musculoskeletal deterioration could not only reveal novel regulatory factors but also might lead to new therapeutic options. Here, we review recent work from a diverse array of species that has revealed novel information regarding physiological and molecular mechanisms that dormant animals may use to conserve musculoskeletal mass despite prolonged inactivity. By highlighting some of the differences and similarities in musculoskeletal biology between vertebrates that experience disparate modes of dormancy, it is hoped that this Review will stimulate new insights and ideas for future studies regarding the regulation of atrophy and osteoporosis in both natural and clinical models of muscle and bone disuse.
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Affiliation(s)
- Beau D. Reilly
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Craig E. Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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24
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Doherty AH, Roteliuk DM, Gookin SE, McGrew AK, Broccardo CJ, Condon KW, Prenni JE, Wojda SJ, Florant GL, Donahue SW. Exploring the Bone Proteome to Help Explain Altered Bone Remodeling and Preservation of Bone Architecture and Strength in Hibernating Marmots. Physiol Biochem Zool 2016; 89:364-76. [DOI: 10.1086/687413] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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McGee-Lawrence M, Buckendahl P, Carpenter C, Henriksen K, Vaughan M, Donahue S. Suppressed bone remodeling in black bears conserves energy and bone mass during hibernation. ACTA ACUST UNITED AC 2016; 218:2067-74. [PMID: 26157160 DOI: 10.1242/jeb.120725] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Decreased physical activity in mammals increases bone turnover and uncouples bone formation from bone resorption, leading to hypercalcemia, hypercalcuria, bone loss and increased fracture risk. Black bears, however, are physically inactive for up to 6 months annually during hibernation without losing cortical or trabecular bone mass. Bears have been shown to preserve trabecular bone volume and architectural parameters and cortical bone strength, porosity and geometrical properties during hibernation. The mechanisms that prevent disuse osteoporosis in bears are unclear as previous studies using histological and serum markers of bone remodeling show conflicting results. However, previous studies used serum markers of bone remodeling that are known to accumulate with decreased renal function, which bears have during hibernation. Therefore, we measured serum bone remodeling markers (BSALP and TRACP) that do not accumulate with decreased renal function, in addition to the concentrations of serum calcium and hormones involved in regulating bone remodeling in hibernating and active bears. Bone resorption and formation markers were decreased during hibernation compared with when bears were physically active, and these findings were supported by histomorphometric analyses of bone biopsies. The serum concentration of cocaine and amphetamine regulated transcript (CART), a hormone known to reduce bone resorption, was 15-fold higher during hibernation. Serum calcium concentration was unchanged between hibernation and non-hibernation seasons. Suppressed and balanced bone resorption and formation in hibernating bears contributes to energy conservation, eucalcemia and the preservation of bone mass and strength, allowing bears to survive prolonged periods of extreme environmental conditions, nutritional deprivation and anuria.
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Affiliation(s)
- Meghan McGee-Lawrence
- Department of Cellular Biology and Anatomy, Georgia Regents University, Augusta, GA 30912, USA
| | - Patricia Buckendahl
- Center for Alcohol Studies, Rutgers University, New Brunswick, NJ 08901, USA
| | - Caren Carpenter
- Department of Orthopaedics and Rehabilitation, Yale University, New Haven, CT 06520, USA
| | - Kim Henriksen
- Nordic Bioscience Biomarkers and Research, Herlev, Denmark
| | - Michael Vaughan
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Seth Donahue
- Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523, USA
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26
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Shimozuru M, Nagashima A, Tanaka J, Tsubota T. Seasonal changes in the expression of energy metabolism-related genes in white adipose tissue and skeletal muscle in female Japanese black bears. Comp Biochem Physiol B Biochem Mol Biol 2016; 196-197:38-47. [DOI: 10.1016/j.cbpb.2016.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/10/2016] [Accepted: 02/10/2016] [Indexed: 10/24/2022]
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27
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Gorissen BMC, Wolschrijn CF, van Vilsteren AAM, van Rietbergen B, van Weeren PR. Trabecular bone of precocials at birth; Are they prepared to run for the wolf(f)? J Morphol 2016; 277:948-56. [PMID: 27098190 PMCID: PMC5111789 DOI: 10.1002/jmor.20548] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/18/2016] [Accepted: 03/20/2016] [Indexed: 02/02/2023]
Abstract
Bone is a dynamic tissue adapting to loading according to “Wolff's law of bone adaptation.” During very early life, however, such a mechanism may not be adequate enough to adapt to the dramatic change in environmental challenges in precocial species. Their neonates are required to stand and walk within hours after birth, in contrast to altricial animals that have much more time to adapt from the intrauterine environment to the outside world. In this study, trabecular bone parameters of the talus and sagittal ridge of the tibia from stillborn but full‐term precocials (calves and foals) were analyzed by micro‐CT imaging in order to identify possible anticipatory mechanisms to loading. Calculated average bone volume fraction in the Shetland pony (49–74%) was significantly higher compared to Warmblood foals (28–51%). Bovine trabecular bone was characterized by a low average bone volume fraction (22–28%), however, more directional anisotropy was found. It is concluded that anticipatory strategies in skeletal development exist in precocial species, which differ per species and are most likely related to anatomical differences in joint geometry and related loading patterns. The underlying regulatory mechanisms are still unknown, but they may be based on a genetic blueprint for the development of bone. More knowledge, both about a possible blueprint and its regulation, will be helpful in understanding developmental bone and joint diseases. J. Morphol. 277:948–956, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ben M C Gorissen
- Department of Pathobiology, Anatomy and Physiology Division, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Claudia F Wolschrijn
- Department of Pathobiology, Anatomy and Physiology Division, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Anouk A M van Vilsteren
- Department of Animal Sciences, Human and Animal Physiology Division, Wageningen University, Wageningen, The Netherlands
| | - Bert van Rietbergen
- Department of Biomedical Engineering, Orthopedic Biomechanics Division, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - P René van Weeren
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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28
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Abstract
Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.
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Affiliation(s)
- Stephen M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, USA
| | - Hannah V Carey
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin, USA
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29
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Abstract
Many environmental conditions can constrain the ability of animals to obtain sufficient food energy, or transform that food energy into useful chemical forms. To survive extended periods under such conditions animals must suppress metabolic rate to conserve energy, water, or oxygen. Amongst small endotherms, this metabolic suppression is accompanied by and, in some cases, facilitated by a decrease in core body temperature-hibernation or daily torpor-though significant metabolic suppression can be achieved even with only modest cooling. Within some ectotherms, winter metabolic suppression exceeds the passive effects of cooling. During dry seasons, estivating ectotherms can reduce metabolism without changes in body temperature, conserving energy reserves, and reducing gas exchange and its inevitable loss of water vapor. This overview explores the similarities and differences of metabolic suppression among these states within adult animals (excluding developmental diapause), and integrates levels of organization from the whole animal to the genome, where possible. Several similarities among these states are highlighted, including patterns and regulation of metabolic balance, fuel use, and mitochondrial metabolism. Differences among models are also apparent, particularly in whether the metabolic suppression is intrinsic to the tissue or depends on the whole-animal response. While in these hypometabolic states, tissues from many animals are tolerant of hypoxia/anoxia, ischemia/reperfusion, and disuse. These natural models may, therefore, serve as valuable and instructive models for biomedical research.
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Affiliation(s)
- James F Staples
- Department of Biology, University of Western Ontario, London, Ontario, Canada
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30
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Wojda SJ, Gridley RA, McGee-Lawrence ME, Drummer TD, Hess A, Kohl F, Barnes BM, Donahue SW. Arctic Ground Squirrels Limit Bone Loss during the Prolonged Physical Inactivity Associated with Hibernation. Physiol Biochem Zool 2015; 89:72-80. [PMID: 27082526 DOI: 10.1086/684619] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Prolonged disuse (e.g., physical inactivity) typically results in increased bone porosity, decreased mineral density, and decreased bone strength, leading to increased fracture risk in many mammals. However, bears, marmots, and two species of ground squirrels have been shown to preserve macrostructural bone properties and bone strength during long seasons of hibernation while they remain mostly inactive. Some small hibernators (e.g., 13-lined ground squirrels) show microstructural bone loss (i.e., osteocytic osteolysis) during hibernation, which is not seen in larger hibernators (e.g., bears and marmots). Arctic ground squirrels (Urocitellus parryii) are intermediate in size between 13-lined ground squirrels and marmots and are perhaps the most extreme rodent hibernator, hibernating for up to 8 mo annually with body temperatures below freezing. The goal of this study was to quantify the effects of hibernation and inactivity on cortical and trabecular bone properties in arctic ground squirrels. Cortical bone geometrical properties (i.e., thickness, cross-sectional area, and moment of inertia) at the midshaft of the femur were not different in animals sampled over the hibernation and active seasons. Femoral ultimate stress tended to be lower in hibernators than in summer animals, but toughness was not affected by hibernation. The area of osteocyte lacunae was not different between active and hibernating animals. There was an increase in osteocytic lacunar porosity in the hibernation group due to increased lacunar density. Trabecular bone volume fraction in the proximal tibia was unexpectedly greater in the hibernation group than in the active group. This study shows that, similar to other hibernators, arctic ground squirrels are able to preserve many bone properties during hibernation despite being physically inactive for up to 8 mo.
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31
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Kueper J, Beyth S, Liebergall M, Kaplan L, Schroeder JE. Evidence for the adverse effect of starvation on bone quality: a review of the literature. Int J Endocrinol 2015; 2015:628740. [PMID: 25810719 PMCID: PMC4355339 DOI: 10.1155/2015/628740] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/27/2015] [Accepted: 01/31/2015] [Indexed: 02/05/2023] Open
Abstract
Malnutrition and starvation's possible adverse impacts on bone health and bone quality first came into the spotlight after the horrors of the Holocaust and the ghettos of World War II. Famine and food restrictions led to a mean caloric intake of 200-800 calories a day in the ghettos and concentration camps, resulting in catabolysis and starvation of the inhabitants and prisoners. Severely increased risks of fracture, poor bone mineral density, and decreased cortical strength were noted in several case series and descriptive reports addressing the medical issues of these individuals. A severe effect of severely diminished food intake and frequently concomitant calcium- and Vitamin D deficiencies was subsequently proven in both animal models and the most common cause of starvation in developed countries is anorexia nervosa. This review attempts to summarize the literature available on the impact of the metabolic response to Starvation on overall bone health and bone quality.
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Affiliation(s)
- Janina Kueper
- Charité University of Medicine, Charitéplatz 1, 10117 Berlin, Germany
| | - Shaul Beyth
- Department of Orthopedic Surgery, Spine Surgery, Hadassah Medical Center, Kiryat Hadassah, P.O. Box 12000, 91120 Jerusalem, Israel
| | - Meir Liebergall
- Department of Orthopedic Surgery, Spine Surgery, Hadassah Medical Center, Kiryat Hadassah, P.O. Box 12000, 91120 Jerusalem, Israel
| | - Leon Kaplan
- Department of Orthopedic Surgery, Spine Surgery, Hadassah Medical Center, Kiryat Hadassah, P.O. Box 12000, 91120 Jerusalem, Israel
| | - Josh E. Schroeder
- Department of Orthopedic Surgery, Spine Surgery, Hadassah Medical Center, Kiryat Hadassah, P.O. Box 12000, 91120 Jerusalem, Israel
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32
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Doherty AH, Florant GL, Donahue SW. Endocrine regulation of bone and energy metabolism in hibernating mammals. Integr Comp Biol 2014; 54:463-83. [PMID: 24556365 DOI: 10.1093/icb/icu001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Precise coordination among organs is required to maintain homeostasis throughout hibernation. This is particularly true in balancing bone remodeling processes (bone formation and resorption) in hibernators experiencing nutritional deprivation and extreme physical inactivity, two factors normally leading to pronounced bone loss in non-hibernating mammals. In recent years, important relationships between bone, fat, reproductive, and brain tissues have come to light. These systems share interconnected regulatory mechanisms of energy metabolism that potentially protect the skeleton during hibernation. This review focuses on the endocrine and neuroendocrine regulation of bone/fat/energy metabolism in hibernators. Hibernators appear to have unique mechanisms that protect musculoskeletal tissues while catabolizing their abundant stores of fat. Furthermore, the bone remodeling processes that normally cause disuse-induced bone loss in non-hibernators are compared to bone remodeling processes in hibernators, and possible adaptations of the bone signaling pathways that protect the skeleton during hibernation are discussed. Understanding the biological mechanisms that allow hibernators to survive the prolonged disuse and fasting associated with extreme environmental challenges will provide critical information regarding the limit of convergence in mammalian systems and of skeletal plasticity, and may contribute valuable insight into the etiology and treatment of human diseases.
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Affiliation(s)
- Alison H Doherty
- *Department of Biology, Colorado State University, Fort Collins, CO 80523-1620, USA; Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1620, USA*Department of Biology, Colorado State University, Fort Collins, CO 80523-1620, USA; Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1620, USA
| | - Gregory L Florant
- *Department of Biology, Colorado State University, Fort Collins, CO 80523-1620, USA; Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1620, USA
| | - Seth W Donahue
- *Department of Biology, Colorado State University, Fort Collins, CO 80523-1620, USA; Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1620, USA
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Chow BA, Donahue SW, Vaughan MR, McConkey B, Vijayan MM. Serum immune-related proteins are differentially expressed during hibernation in the American black bear. PLoS One 2013; 8:e66119. [PMID: 23825529 PMCID: PMC3692520 DOI: 10.1371/journal.pone.0066119] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 05/01/2013] [Indexed: 11/23/2022] Open
Abstract
Hibernation is an adaptation to conserve energy in the face of extreme environmental conditions and low food availability that has risen in several animal phyla. This phenomenon is characterized by reduced metabolic rate (∼25% of the active basal metabolic rate in hibernating bears) and energy demand, while other physiological adjustments are far from clear. The profiling of the serum proteome of the American black bear (Ursus americanus) may reveal specific proteins that are differentially modulated by hibernation, and provide insight into the remarkable physiological adaptations that characterize ursid hibernation. In this study, we used differential gel electrophoresis (DIGE) analysis, liquid chromatography coupled to tandem mass spectrometry, and subsequent MASCOT analysis of the mass spectra to identify candidate proteins that are differentially expressed during hibernation in captive black bears. Seventy serum proteins were identified as changing by ±1.5 fold or more, out of which 34 proteins increased expression during hibernation. The majority of identified proteins are involved in immune system processes. These included α2-macroglobulin, complement components C1s and C4, immunoglobulin μ and J chains, clusterin, haptoglobin, C4b binding protein, kininogen 1, α2-HS-glycoprotein, and apoplipoproteins A-I and A-IV. Differential expression of a subset of these proteins identified by proteomic analysis was also confirmed by immunodetection. We propose that the observed serum protein changes contribute to the maintenance of the hibernation phenotype and health, including increased capacities for bone maintenance and wound healing during hibernation in bears.
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Affiliation(s)
- Brian A. Chow
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Seth W. Donahue
- Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado, United States of America
| | - Michael R. Vaughan
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Brendan McConkey
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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34
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Shimozuru M, Iibuchi R, Yoshimoto T, Nagashima A, Tanaka J, Tsubota T. Pregnancy during hibernation in Japanese black bears: effects on body temperature and blood biochemical profiles. J Mammal 2013. [DOI: 10.1644/12-mamm-a-246.1] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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35
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Hibernating bears (Ursidae): metabolic magicians of definite interest for the nephrologist. Kidney Int 2012; 83:207-12. [PMID: 23254895 DOI: 10.1038/ki.2012.396] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Muscle loss, osteoporosis, and vascular disease are common in subjects with reduced renal function. Despite intensive research of the underlying risk factors and mechanisms driving these phenotypes, we still lack effective treatment strategies for this underserved patient group. Thus, new approaches are needed to identify effective treatments. We believe that nephrologists could learn much from biomimicry; i.e., studies of nature's models to solve complicated physiological problems and then imitate these fascinating solutions to develop novel interventions. The hibernating bear (Ursidae) should be of specific interest to the nephrologist as they ingest no food or water for months, remaining anuric and immobile, only to awaken with low blood urea nitrogen levels, healthy lean body mass, strong bones, and without evidence for thrombotic complications. Identifying the mechanisms by which bears prevent the development of azotemia, sarcopenia, osteoporosis, and atherosclerosis despite being inactive and anuric could lead to novel interventions for both prevention and treatment of patients with chronic kidney disease.
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36
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Gray SK, McGee-Lawrence ME, Sanders JL, Condon KW, Tsai CJ, Donahue SW. Black bear parathyroid hormone has greater anabolic effects on trabecular bone in dystrophin-deficient mice than in wild type mice. Bone 2012; 51:578-85. [PMID: 22584007 PMCID: PMC3412940 DOI: 10.1016/j.bone.2012.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 05/03/2012] [Accepted: 05/04/2012] [Indexed: 12/12/2022]
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease that has deleterious consequences in muscle and bone, leading to decreased mobility, progressive osteoporosis, and premature death. Patients with DMD experience a higher-than-average fracture rate, particularly in the proximal and distal femur and proximal tibia. The dystrophin-deficient mdx mouse is a model of DMD that demonstrates muscle degeneration and fibrosis and osteoporosis. Parathyroid hormone, an effective anabolic agent for post-menopausal and glucocorticoid-induced osteoporosis, has not been explored for DMD. Black bear parathyroid hormone (bbPTH) has been implicated in the maintenance of bone properties during extended periods of disuse (hibernation). We cloned bbPTH and found 9 amino acid residue differences from human PTH. Apoptosis was mitigated and cAMP was activated by bbPTH in osteoblast cultures. We administered 28nmol/kg of bbPTH 1-84 to 4-week old male mdx and wild type mice via daily (5×/week) subcutaneous injection for 6 weeks. Vehicle-treated mdx mice had 44% lower trabecular bone volume fraction than wild type mice. No changes were found in femoral cortical bone geometry or mechanical properties with bbPTH treatment in wild type mice, and only medio-lateral moment of inertia changed with bbPTH treatment in mdx femurs. However, μCT analyses of the trabecular regions of the distal femur and proximal tibia showed marked increases in bone volume fraction with bbPTH treatment, with a greater anabolic response (7-fold increase) in mdx mice than wild type mice (2-fold increase). Trabecular number increased in mdx long bone, but not wild type bone. Additionally, greater osteoblast area and decreased osteoclast area were observed with bbPTH treatment in mdx mice. The heightened response to PTH in mdx bone compared to wild type suggests a link between dystrophin deficiency, altered calcium signaling, and bone. These findings support further investigation of PTH as an anabolic treatment for DMD-induced osteoporosis.
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Affiliation(s)
- Sarah K Gray
- Michigan Tech University, Dept. of Biomedical Engineering, 309 M&M Bldg., 1400 Townsend Dr., Houghton, MI 49931, USA
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37
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Shimozuru M, Kamine A, Tsubota T. Changes in expression of hepatic genes involved in energy metabolism during hibernation in captive, adult, female Japanese black bears (Ursus thibetanus japonicus). Comp Biochem Physiol B Biochem Mol Biol 2012; 163:254-61. [PMID: 22771378 DOI: 10.1016/j.cbpb.2012.06.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/29/2012] [Accepted: 06/29/2012] [Indexed: 01/17/2023]
Abstract
Hibernating bears survive up to 6 months without feeding by utilizing stored body fat as fuel. To investigate how bears maintain energy homeostasis during hibernation, we analyzed changes in mRNA expression of hepatic genes involved in energy metabolism throughout the hibernation period in captive, adult, female Japanese black bears (Ursus thibetanus japonicus). Real-time PCR analysis revealed down-regulation of glycolysis- (e.g., glucokinase), amino acid catabolism- (e.g., alanine aminotransferase) and de novo lipogenesis-related genes (e.g., acetyl-CoA carboxylase 1), and up-regulation of gluconeogensis- (e.g., pyruvate carboxylase), β-oxidation- (i.e., uncoupling protein 2) and ketogenesis-related genes (i.e., 3-hydroxy-3-methylglutary-CoA synthase 2), during hibernation, compared to the active period (June). In addition, we found that glycolysis-related genes (i.e., glucokinase and pyruvate kinase) were more suppressed in the early phase of hibernation (January) compared to the late phase (March). One week after the commencement of feeding in April, expression levels of most genes returned to levels comparable to those seen in June, but β-oxidation-related genes were still up-regulated during this period. These results suggest that the modulation of gene expression is not static, but changes throughout the hibernation period. The transcriptional modulation during hibernation represents a unique physiological adaptation to prolonged fasting in bears.
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Affiliation(s)
- Michito Shimozuru
- Laboratory of Wildlife Biology and Medicine, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
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Preservation of bone mass and structure in hibernating black bears (Ursus americanus) through elevated expression of anabolic genes. Funct Integr Genomics 2012; 12:357-65. [PMID: 22351243 DOI: 10.1007/s10142-012-0266-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 01/12/2012] [Accepted: 02/07/2012] [Indexed: 10/28/2022]
Abstract
Physical inactivity reduces mechanical load on the skeleton, which leads to losses of bone mass and strength in non-hibernating mammalian species. Although bears are largely inactive during hibernation, they show no loss in bone mass and strength. To obtain insight into molecular mechanisms preventing disuse bone loss, we conducted a large-scale screen of transcriptional changes in trabecular bone comparing winter hibernating and summer non-hibernating black bears using a custom 12,800 probe cDNA microarray. A total of 241 genes were differentially expressed (P < 0.01 and fold change >1.4) in the ilium bone of bears between winter and summer. The Gene Ontology and Gene Set Enrichment Analysis showed an elevated proportion in hibernating bears of overexpressed genes in six functional sets of genes involved in anabolic processes of tissue morphogenesis and development including skeletal development, cartilage development, and bone biosynthesis. Apoptosis genes demonstrated a tendency for downregulation during hibernation. No coordinated directional changes were detected for genes involved in bone resorption, although some genes responsible for osteoclast formation and differentiation (Ostf1, Rab9a, and c-Fos) were significantly underexpressed in bone of hibernating bears. Elevated expression of multiple anabolic genes without induction of bone resorption genes, and the down regulation of apoptosis-related genes, likely contribute to the adaptive mechanism that preserves bone mass and structure through prolonged periods of immobility during hibernation.
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Doherty AH, Frampton JD, Vinyard CJ. Hibernation does not reduce cortical bone density, area or second moments of inertia in woodchucks (Marmota monax). J Morphol 2012; 273:604-17. [DOI: 10.1002/jmor.20007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 11/16/2011] [Accepted: 11/30/2011] [Indexed: 11/12/2022]
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Wojda SJ, McGee-Lawrence ME, Gridley RA, Auger J, Black HL, Donahue SW. Yellow-bellied marmots (Marmota flaviventris) preserve bone strength and microstructure during hibernation. Bone 2012; 50:182-8. [PMID: 22037004 PMCID: PMC3489026 DOI: 10.1016/j.bone.2011.10.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 09/12/2011] [Accepted: 10/11/2011] [Indexed: 11/23/2022]
Abstract
Reduced skeletal loading typically results in decreased bone strength and increased fracture risk for humans and many other animals. Previous studies have shown bears are able to prevent bone loss during the disuse that occurs during hibernation. Studies with smaller hibernators, which arouse intermittently during hibernation, show that they may lose bone at the microstructural level. These small hibernators, like bats and squirrels, do not utilize intracortical remodeling. However, slightly larger mammals like marmots do. In this study we examined the effects of hibernation on bone structural, mineral, and mechanical properties in yellow-bellied marmots (Marmota flaviventris). This was done by comparing cortical bone properties in femurs and trabecular bone properties in tibias from marmots killed before hibernation (fall) and after hibernation (spring). Age data were not available for this study; however, based on femur length the post-hibernation marmots were larger than the pre-hibernation marmots. Thus, cross-sectional properties were normalized by allometric functions of bone length for comparisons between pre- and post-hibernation. Cortical thickness and normalized cortical area were higher in post-hibernation samples; no other normalized cross-sectional properties were different. No cortical bone microstructural loss was evident in osteocyte lacunar measurements, intracortical porosity, or intracortical remodeling cavity density. Osteocyte lacunar area, porosity, and density were surprisingly lower in post-hibernation samples. Trabecular bone volume fraction was not different between pre- and post-hibernation. Measures of both trabecular and cortical bone mineral content were higher in post-hibernation samples. Three-point bending failure load, failure energy, elastic energy, ultimate stress, and yield stress were all higher in post-hibernation samples. These results support the idea that, like bears, marmots are able to prevent disuse osteoporosis during hibernation, thus preventing increased fracture risk and promoting survival of the extreme environmental conditions that occur in hibernation.
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Affiliation(s)
- Samantha J Wojda
- Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University, Townsend Drive, Houghton, MI 49931, USA
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Alexandre C, Vico L. Pathophysiology of bone loss in disuse osteoporosis. Joint Bone Spine 2011; 78:572-6. [DOI: 10.1016/j.jbspin.2011.04.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2011] [Indexed: 12/31/2022]
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Rogers TA, Bedrosian B, Graham J, Foresman KR. Lead exposure in large carnivores in the greater Yellowstone ecosystem. J Wildl Manage 2011. [DOI: 10.1002/jwmg.277] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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McGee-Lawrence ME, Stoll DM, Mantila ER, Fahrner BK, Carey HV, Donahue SW. Thirteen-lined ground squirrels (Ictidomys tridecemlineatus) show microstructural bone loss during hibernation but preserve bone macrostructural geometry and strength. ACTA ACUST UNITED AC 2011; 214:1240-7. [PMID: 21430199 DOI: 10.1242/jeb053520] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lack of activity causes bone loss In most animals. Hibernating bears have physiological processes to prevent cortical and trabecular bone loss associated with reduced physical activity, but different mechanisms of torpor among hibernating species may lead to differences in skeletal responses to hibernation. There are conflicting reports regarding whether small mammals experience bone loss during hibernation. To investigate this phenomenon, we measured cortical and trabecular bone properties in physically active and hibernating juvenile and adult 13-lined ground squirrels (Ictidomys tridecemlineatus, previous genus name Spermophilus). Cortical bone geometry, strength and mineral content were similar in hibernating compared with active squirrels, suggesting that hibernation did not cause macrostructural cortical bone loss. Osteocyte lacunar size increased (linear regression, P=0.001) over the course of hibernation in juvenile squirrels, which may indicate an osteocytic role in mineral homeostasis during hibernation. Osteocyte lacunar density and porosity were greater (+44 and +59%, respectively; P<0.0001) in hibernating compared with active squirrels, which may reflect a decrease in osteoblastic activity (per cell) during hibernation. Trabecular bone volume fraction in the proximal tibia was decreased (-20%; P=0.028) in hibernating compared with physically active adult squirrels, but was not different between hibernating and active juvenile squirrels. Taken together, these data suggest that 13-lined ground squirrels may be unable to prevent microstructural losses of cortical and trabecular bone during hibernation, but importantly may possess a biological mechanism to preserve cortical bone macrostructure and strength during hibernation, thus preventing an increased risk of bone fracture during remobilization in the spring.
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Fink T, Rasmussen JG, Emmersen J, Pilgaard L, Fahlman Å, Brunberg S, Josefsson J, Arnemo JM, Zachar V, Swenson JE, Fröbert O. Adipose-derived stem cells from the brown bear (Ursus arctos) spontaneously undergo chondrogenic and osteogenic differentiation in vitro. Stem Cell Res 2011; 7:89-95. [DOI: 10.1016/j.scr.2011.03.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 01/16/2011] [Accepted: 03/17/2011] [Indexed: 02/08/2023] Open
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Vitamin D status and bone and connective tissue turnover in brown bears (Ursus arctos) during hibernation and the active state. PLoS One 2011; 6:e21483. [PMID: 21731765 PMCID: PMC3121767 DOI: 10.1371/journal.pone.0021483] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 05/31/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Extended physical inactivity causes disuse osteoporosis in humans. In contrast, brown bears (Ursus arctos) are highly immobilised for half of the year during hibernation without signs of bone loss and therefore may serve as a model for prevention of osteoporosis. AIM To study 25-hydroxy-vitamin D (25OHD) levels and bone turnover markers in brown bears during the hibernating state in winter and during the active state in summer. We measured vitamin D subtypes (D₂ and D₃), calcitropic hormones (parathyroid hormone [PTH], 1,25-dihydroxy-vitamin D [1,25(OH)₂D]) and bone turnover parameters (osteocalcin, ICTP, CTX-I), PTH, serum calcium and PIIINP. MATERIAL AND METHODS We drew blood from seven immobilised wild brown bears during hibernation in February and in the same bears while active in June. RESULTS Serum 25-hydroxy-cholecalciferol (25OHD₃) was significantly higher in the summer than in the winter (22.8±4.6 vs. 8.8±2.1 nmol/l, two tailed p-2p = 0.02), whereas 25-hydroxy-ergocalciferol (25OHD₂) was higher in winter (54.2±8.3 vs. 18.7±1.7 nmol/l, 2p<0.01). Total serum calcium and PTH levels did not differ between winter and summer. Activated 1,25(OH)₂D demonstrated a statistically insignificant trend towards higher summer levels. Osteocalcin levels were higher in summer than winter, whereas other markers of bone turnover (ICTP and CTX-I) were unchanged. Serum PIIINP, which is a marker of connective tissue and to some degree muscle turnover, was significantly higher during summer than during winter. CONCLUSIONS Dramatic changes were documented in the vitamin D₃/D₂ ratio and in markers of bone and connective tissue turnover in brown bears between hibernation and the active state. Because hibernating brown bears do not develop disuse osteoporosis, despite extensive physical inactivity we suggest that they may serve as a model for the prevention of this disease.
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Nieminen P, Finnilä MAJ, Tuukkanen J, Jämsä T, Mustonen AM. Preservation of bone mass and biomechanical properties during winter sleep--the raccoon dog (Nyctereutes procyonoides) as a novel model species. Bone 2011; 48:878-84. [PMID: 21146643 DOI: 10.1016/j.bone.2010.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 11/15/2010] [Accepted: 12/02/2010] [Indexed: 01/22/2023]
Abstract
It has been established that almost 40% of postmenopausal women in the United States have osteopenia and models to study its prevention are thus urgently needed. Bears (Ursus spp.) displaying winter sleep were previously introduced as promising models to study the treatment of disuse-induced bone loss. The present study examined the potential of another analogous model species, the raccoon dog (Nyctereutes procyonoides), in bone research. Similar to bears, raccoon dogs display prolonged passivity and catabolism in winter, but they are of a moderate body mass, easy to handle and reared on farms. Wild specimens (n=51) were hunted in winter 2007-2008. The bone mineral density of femoral diaphysis and neck was examined with peripheral quantitative computed tomography, after which their mechanical properties were tested with the three-point bending and femoral neck loading tests. A subsample of the specimens was analyzed histologically. While the body mass of the raccoon dogs decreased from 7.0±0.3 to 4.5±0.2 kg (-36%) during winter, the bone mass and biomechanical properties remained unchanged despite of heavy wintertime catabolism similar to bears. Thus, the cortical mineral density remained at approximately 1400 mg/cm(3), the trabecular mineral density at 450 mg/cm(3) and the maximum load of the femoral neck at 700 N. However, in histological samples, the proportion of osteoid perimeter vs. mineralized bone perimeter decreased during wintering. A possible mechanism of bone mass preservation is the endocrine status of overwintering raccoon dogs, which could participate in preventing bone loss.
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Affiliation(s)
- Petteri Nieminen
- University of Eastern Finland, Department of Medicine, Institute of Biomedicine, P.O. Box 1674, FI-70211, Kuopio, Finland.
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Motyl KJ, Rosen CJ. Temperatures rising: brown fat and bone. DISCOVERY MEDICINE 2011; 11:179-185. [PMID: 21447277 PMCID: PMC3629549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Caloric restriction is associated with a reduction in body weight and temperature, as well as a reduction in trabecular bone volume and paradoxically an increase in adipocytes within the bone marrow. The nature of these adipocytes is uncertain, although there is emerging evidence of a direct relationship between bone remodeling and brown adipocytes. For example, in heterotrophic ossification, brown adipocytes set up a hypoxic gradient that leads to vascular invasion, chondrocyte differentiation, and subsequent bone formation. Additionally, deletion of retinoblastoma protein in an osteosarcoma model leads to increased hibernoma (brown fat tumor). Brown adipose tissue (BAT) becomes senescent with age at a time when thermoregulation is altered, bone loss becomes apparent, and sympathetic activity increases. Interestingly, heart rate is an unexpected but good predictor of fracture risk in elderly individuals, pointing to a key role for the sympathetic nervous system in senile osteoporosis. Hence the possibility exists that BAT could play an indirect role in age-related bone loss. However, evidence of an indirect effect from thermogenic dysfunction on bone loss is currently limited. Here, we present current evidence for a relationship between brown adipose tissue and bone as well as provide novel insights into the effects of thermoregulation on bone mineral density.
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Affiliation(s)
- Katherine J. Motyl
- Maine Medical Center Research Institute 81 Research Drive Scarborough, ME 04074
| | - Clifford J. Rosen
- Maine Medical Center Research Institute 81 Research Drive Scarborough, ME 04074
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Zhao S, Shao C, Goropashnaya AV, Stewart NC, Xu Y, Tøien Ø, Barnes BM, Fedorov VB, Yan J. Genomic analysis of expressed sequence tags in American black bear Ursus americanus. BMC Genomics 2010; 11:201. [PMID: 20338065 PMCID: PMC2996962 DOI: 10.1186/1471-2164-11-201] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 03/26/2010] [Indexed: 11/18/2022] Open
Abstract
Background Species of the bear family (Ursidae) are important organisms for research in molecular evolution, comparative physiology and conservation biology, but relatively little genetic sequence information is available for this group. Here we report the development and analyses of the first large scale Expressed Sequence Tag (EST) resource for the American black bear (Ursus americanus). Results Comprehensive analyses of molecular functions, alternative splicing, and tissue-specific expression of 38,757 black bear EST sequences were conducted using the dog genome as a reference. We identified 18 genes, involved in functions such as lipid catabolism, cell cycle, and vesicle-mediated transport, that are showing rapid evolution in the bear lineage Three genes, Phospholamban (PLN), cysteine glycine-rich protein 3 (CSRP3) and Troponin I type 3 (TNNI3), are related to heart contraction, and defects in these genes in humans lead to heart disease. Two genes, biphenyl hydrolase-like (BPHL) and CSRP3, contain positively selected sites in bear. Global analysis of evolution rates of hibernation-related genes in bear showed that they are largely conserved and slowly evolving genes, rather than novel and fast-evolving genes. Conclusion We provide a genomic resource for an important mammalian organism and our study sheds new light on the possible functions and evolution of bear genes.
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Affiliation(s)
- Sen Zhao
- CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes of Biological Sciences, 320 Yue Yang Road, Shanghai, 200031, China
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van Breukelen F, Krumschnabel G, Podrabsky JE. Vertebrate cell death in energy-limited conditions and how to avoid it: what we might learn from mammalian hibernators and other stress-tolerant vertebrates. Apoptosis 2010; 15:386-99. [DOI: 10.1007/s10495-010-0467-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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