Investigating the mechanism for maintaining eucalcemia despite immobility and anuria in the hibernating American black bear (Ursus americanus)

Seger, Rita L.; Cross, Randal A.; Rosen, Clifford J.; Causey, Robert; Gundberg, Caren M.; Carpenter, Thomas O.; Chen, Thomas; Halteman, William A.; Holick, Michael F.; Jakubas, Walter J.; Keisler, D.H.; Seger, Richard M.; Servello, Frederick A.

doi:10.1016/j.bone.2011.08.017

Cited by 36 publications

(43 citation statements)

References 43 publications

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“…It has been hypothesised that rates of bone resorption and formation remain stable in hibernating Ursus to help prevent calcium imbalance (Donahue et al, 2006). However, previous investigations using serum and histological markers of bone remodelling to investigate this idea provided inconsistent data (Donahue et al, 2006;Seger et al, 2011), possibly as a result of the effect of decreased renal function on serum markers. A more recent study using more reliable markers of bone turnover [bone-specific alkaline phosphatase (BSALP) and tartrate-resistant acid phosphatase (TRACP)] provided strong evidence that bone resorption and formation are suppressed during hibernation in black bears, in contrast to non-hibernating animals undergoing disuse (Fig.…”

Section: Mechanisms Underpinning the Inhibition Of Osteoporosismentioning

confidence: 87%

“…Despite the knowledge that sclerostin plays an important role in bone mechanotransduction in the majority of mammals, very little is known about sclerostin and related pathways during dormancy. Seger et al (2011) measured serum sclerostin levels in both hibernating and non-hibernating black bears, and found that there was no significant difference between the two groups. However, a subset of hibernating bears did show increased levels of serum sclerostin, which is a skeletal signal of unloading.…”

Section: Mechanisms Underpinning the Inhibition Of Osteoporosismentioning

confidence: 99%

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Prevention of muscle wasting and osteoporosis: the value of examining novel animal models

Reilly

Franklin

2016

Journal of Experimental Biology

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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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Section: Mechanisms Underpinning the Inhibition Of Osteoporosismentioning

confidence: 87%

Section: Mechanisms Underpinning the Inhibition Of Osteoporosismentioning

confidence: 99%

Prevention of muscle wasting and osteoporosis: the value of examining novel animal models

Reilly

Franklin

2016

Journal of Experimental Biology

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“…In denning bears, the Vit D-25 levels increased (Seger et al, 2011) and they could have participated in the prevention of bone loss. This is clearly different from the situation in A B Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The increasing sex steroid levels towards the mating season (Asikainen et al, 2003) could also promote the maintenance of bone mass (Horstman et al, 2012). Wintertime fasting does not affect the plasma leptin concentrations of raccoon dogs (Nieminen et al, 2002;Kinnunen et al, 2015), whereas in denning bears the leptin levels increase or remain stable (Donahue et al, 2006a;Seger et al, 2011). It has been suggested that the antiosteogenic effects of leptin are mediated by noradrenaline that is released through the activation of the sympathetic nervous system and acts on the β 2 -adrenergic receptors on osteoblasts (Elefteriou et al, 2004;He et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…For instance, denning bears experience increased serum cortisol levels (Donahue et al, 2003a, b), which could as a single finding indicate bone loss. Interestingly, the levels of sclerostin, which decreases bone formation, can be elevated in hibernating bears (Seger et al, 2011). Sclerostin antibody treatment is being investigated for its potential to prevent unloadinginduced osteoporosis (Qin et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

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Raccoon dog model shows preservation of bone during prolonged catabolism and reduced physical activity

Mustonen

Finnilä

Puukka

et al. 2017

Journal of Experimental Biology

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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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Calcium homeostasis during hibernation and in mechanical environments disrupting calcium homeostasis

et al. 2020

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Investigating the mechanism for maintaining eucalcemia despite immobility and anuria in the hibernating American black bear (Ursus americanus)

Cited by 36 publications

References 43 publications

Prevention of muscle wasting and osteoporosis: the value of examining novel animal models

Prevention of muscle wasting and osteoporosis: the value of examining novel animal models

Raccoon dog model shows preservation of bone during prolonged catabolism and reduced physical activity

Calcium homeostasis during hibernation and in mechanical environments disrupting calcium homeostasis

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