Effects of spaceflight on bone mineralization in the rhesus monkey

Zérath, E.; Novikov, V. V.; LeBlanc, Adrian; Бакулин, А. В.; Оганов, В. С.; Grynpas, Marc D.

doi:10.1152/jappl.1996.81.1.194

Cited by 35 publications

(19 citation statements)

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“…Spaceflight decreases trabecular indices of bone formation in the iliac crest of monkeys [37,38], and human astronauts experience an imbalance in bone resorption and bone formation during spaceflight [2,39], which probably causes the cortical bone loss that is observed after 4-6 months in space [40,41]. Similarly, patients with acute spinal cord injury (< 6 months postinjury) experience increased bone resorption and increased urinary calcium excretion, which likely explains why spinal cord injury patients lose bone structural properties and demonstrate increased rates of bone fracture [12,16,42,43].…”

Section: Discussionmentioning

confidence: 99%

Decreased bone turnover with balanced resorption and formation prevent cortical bone loss during disuse (hibernation) in grizzly bears (Ursus arctos horribilis)

McGee

Maki

Johnson

et al. 2008

Bone

102

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Disuse uncouples bone formation from resorption, leading to increased porosity, decreased bone geometrical properties, and decreased bone mineral content which compromises bone mechanical properties and increases fracture risk. However, black bear bone properties are not adversely affected by aging despite annual periods of disuse (i.e., hibernation), which suggests that bears either prevent bone loss during disuse or lose bone and subsequently recover it at a faster rate than other animals. Here we show decreased cortical bone turnover during hibernation with balanced formation and resorption in grizzly bear femurs. Hibernating grizzly bear femurs were less porous and more mineralized, and did not demonstrate any changes in cortical bone geometry or whole bone mechanical properties compared to active grizzly bear femurs. The activation frequency of intracortical remodeling was 75% lower during hibernation than during periods of physical activity, but the normalized mineral apposition rate was unchanged. These data indicate bone turnover decreases during hibernation, but osteons continue to refill at normal rates. There were no changes in regional variation of porosity, geometry, or remodeling indices in femurs from hibernating bears, indicating that hibernation did not preferentially affect one region of the cortex. Thus, grizzly bears prevent bone loss during disuse by decreasing bone turnover and maintaining balanced formation and resorption, which preserves bone structure and strength. These results support the idea that bears possess a biological mechanism to prevent disuse osteoporosis.

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Section: Discussionmentioning

confidence: 99%

Decreased bone turnover with balanced resorption and formation prevent cortical bone loss during disuse (hibernation) in grizzly bears (Ursus arctos horribilis)

McGee

Maki

Johnson

et al. 2008

Bone

102

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“…Rahkmanov et al reported mineral loss in the proximal tibia after 2 weeks in space during an earlier mission [12]. In this mission, Zerath et al found less surface area involved and reduced mineralization rates in iliac crest biopsies, but at the organ level there was only a tendency for decreased mineral content during flight in two monkeys, and no changes in four chaired controls [22]. Whether these changes in the mineral content were associated with changes in bone biomechanics in the flight or control monkeys is not known.…”

Section: Introductionmentioning

confidence: 97%

Effects of chair restraint on the strength of the tibia in rhesus monkeys

Hutchinson

Бакулин

Rakhmanov

et al. 2001

J of Medical Primatology

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To determine the effects of the relative inactivity and unloading on the strength of the tibias of monkeys, Macaca mulatta, we used a non-invasive test to measure bending stiffness, or EI (Nm2), a mechanical property. The technique was validated by comparisons of in vivo measurements with standard measures of EI in the same bones post-mortem (r2 = 0.95, P < 0.0001). Inter-test precision was 4.28+/-1.4%. Normative data in 24 monkeys, 3.0+/-0.7 years and 3.6+/-0.6 kg, revealed EI to be 16% higher in the right than left tibia (4.4+/-1.6 vs. 3.7+/-1.6 Nm2, P < 0.05). Five monkeys, restrained in chairs for 14 days, showed decreases in EI. There were no changes in EI in two chaired monkeys that lost weight during a 2-week space flight. The factors that account for both the decreases in bone mechanical properties after chair restraint at 1 g and lack of change after microgravity remain to be identified. Metabolic factors associated with body weight changes are suggested by our results.

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“…Although each mission was limited to the participation of only two nonhuman primates in orbit for ϳ2 wk, the effects of microgravity on bone were evaluated by biopsies after the flight (38,39). As well, exercise activity, which may confound the interpretation of bone responses, was controlled during the flight.…”

mentioning

confidence: 99%

The calcium endocrine system of adolescent rhesus monkeys and controls before and after spaceflight

Arnaud

Navidi

Deftos

et al. 2002

American Journal of Physiology-Endocrinology and Metabolism

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. The calcium endocrine system of adolescent rhesus monkeys and controls before and after spaceflight. Am J Physiol Endocrinol Metab 282: E514-E521, 2002; 10.1152/ajpendo.00299.2001.-The calcium endocrine system of nonhuman primates can be influenced by chairing for safety and the weightless environment of spaceflight. The serum of two rhesus monkeys flown on the Bion 11 mission was assayed pre-and postflight for vitamin D metabolites, parathyroid hormone, calcitonin, parameters of calcium homeostasis, cortisol, and indexes of renal function. Results were compared with the same measures from five monkeys before and after chairing for a flight simulation study. Concentrations of 1,25-dihydroxyvitamin D were 72% lower after the flight than before, and more than after chairing on the ground (57%, P Ͻ 0.05). Decreases in parathyroid hormone did not reach significance. Calcitonin showed modest decreases postflight (P Ͻ 0.02). Overall, effects of spaceflight on the calcium endocrine system were similar to the effects of chairing on the ground, but were more pronounced. Reduced intestinal calcium absorption, losses in body weight, increases in cortisol, and higher postflight blood urea nitrogen were the changes in flight monkeys that distinguished them from the flight simulation study animals. rhesus monkey; 1,25-dihydroxyvitamin D EXPERIMENTS CONDUCTED on the Russian biosatellite missions have contributed a great deal of information on the effects of spaceflight on bone in the primate. Although each mission was limited to the participation of only two nonhuman primates in orbit for ϳ2 wk, the effects of microgravity on bone were evaluated by biopsies after the flight (38, 39). As well, exercise activity, which may confound the interpretation of bone responses, was controlled during the flight. Reduced mechanical stress is known to depress new bone formation in localized areas of the skeleton at any age (2) and to stimulate bone resorption in the mature skeleton (18,40). The role of the calcium endocrine system in this response of bone tissue has been studied through the analyses of blood samples acquired during ground-based simulations (2, 17, 40) and spaceflight (23, 30). Smith et. al (30) note in their detailed listing of human spaceflight results that the two major calcemic hormones, parathyroid hormone and 1,25-dihydroxyvitamin D, were suppressed and that calcitonin was unchanged. Decreases in parathyroid hormone are initiated by the release of calcium, not always detectable as an increase in serum, from an unloaded skeletal site. Suppressed parathyroid hormone would operate to reduce osteoclastic resorption and bone loss directly and indirectly by reduced intestinal absorption of calcium through decreases in the production of the vitamin D hormone. Collectively, these observations in humans place the calcium endocrine system in a role that responds to the biomechanical effects of weightlessness on bone that initiates increased resorption and decreased formation at different skeletal sites.In juvenile monkeys, pre...

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Effects of spaceflight on bone mineralization in the rhesus monkey

Cited by 35 publications

References 0 publications

Decreased bone turnover with balanced resorption and formation prevent cortical bone loss during disuse (hibernation) in grizzly bears (Ursus arctos horribilis)

Decreased bone turnover with balanced resorption and formation prevent cortical bone loss during disuse (hibernation) in grizzly bears (Ursus arctos horribilis)

Effects of chair restraint on the strength of the tibia in rhesus monkeys

The calcium endocrine system of adolescent rhesus monkeys and controls before and after spaceflight

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