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Skiba G, Sobol M, Raj S. Bone mineralisation, mechanical properties and body phosphorus content in growing gilts as affected by protein or feed intake during depletion-repletion periods. Arch Anim Nutr 2018; 72:478-491. [PMID: 30324824 DOI: 10.1080/1745039x.2018.1527145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The influence of feed or protein depletion-repletion on phosphorus balance, and bone characteristics was studied on 70 growing pigs from 90 to 168 d of age. During depletion period (90-118 d of age), C pigs were fed semi ad libitum (95% ad libitum intake) on control diet; FR pigs (feed-restricted group) consumed 40% less of control diet compared to C pigs; PR pigs (protein-restricted group) were fed semi ad libitum a low-protein diet containing 40% less protein than control diet. During repletion period (119-168 d of age), daily allowances for C pigs were equal of 95% ad libitum intake. Remaining pigs consumed a control diet at the same amount as C pigs. Pigs were slaughtered at 90 d of age ("zero" animals, n = 7), following seven animals from each group at d 118, 146 and 168 of age. At 118 d of age, phosphorus content in the body was lower (p < 0.001) in FR than C and PR pigs. Lower phosphorus deposition and utilisation was observed in FR animals. Humerus in FR pigs was lighter, had lower mineral content and density, but had greater stiffness than in PR and C pigs. During repletion period, FR pigs deposited more phosphorus and had better phosphorus utilisation than C and PR pigs. Humerus mineral density was greater in FR and PR than in C pigs. Humerus strength was the highest in PR pigs, and the lowest in FR pigs. Humerus stiffness was greater in PR than in C and FR pigs. In conclusion, during depletion period feed restriction affects bone growth more than protein restriction, and bone strength is less sensitive, than other bone characteristics, to feed restriction. Reductions in measured bone indices observed after lower feed intake can be fully compensated during the repletion period and resulted mainly from better utilisation of minerals.
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Affiliation(s)
- Grzegorz Skiba
- a The Kielanowski Institute of Animal Physiology and Nutrition , Polish Academy of Sciences , Jabłonna , Poland
| | - Monika Sobol
- a The Kielanowski Institute of Animal Physiology and Nutrition , Polish Academy of Sciences , Jabłonna , Poland
| | - Stanisława Raj
- a The Kielanowski Institute of Animal Physiology and Nutrition , Polish Academy of Sciences , Jabłonna , Poland
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DiVasta AD, Feldman HA, Rubin CT, Gallagher JS, Stokes N, Kiel DP, Snyder BD, Gordon CM. The ability of low-magnitude mechanical signals to normalize bone turnover in adolescents hospitalized for anorexia nervosa. Osteoporos Int 2017; 28:1255-1263. [PMID: 27909781 PMCID: PMC9769086 DOI: 10.1007/s00198-016-3851-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/21/2016] [Indexed: 12/24/2022]
Abstract
UNLABELLED We sought to determine whether low-magnitude mechanical stimulation (LMMS) normalizes bone turnover among adolescents hospitalized for anorexia nervosa (AN). Brief, daily LMMS prevents the decline in bone turnover typically seen during bed rest in AN. LMMS may have application for patients with AN in the inpatient setting to protect bone health. INTRODUCTION Malnourished adolescents with AN requiring medical hospitalization are at high risk for rapid reduction in skeletal quality. Even short-term bed rest can suppress normal patterns of bone turnover. We sought to determine whether LMMS normalizes bone turnover among adolescents hospitalized for complications of AN. METHODS In this randomized, double-blind trial, we prospectively enrolled adolescent females (n = 41) with AN, age 16.3 ± 1.9 years (mean ± SD) and BMI 15.6 ± 1.7 kg/m2. Participants were randomized to stand on a platform delivering LMMS (0.3 g at 32-37 Hz) or placebo platform for 10 min/day for 5 days. Serum markers of bone formation [bone-specific alkaline phosphatase (BSAP)], turnover [osteocalcin (OC)], and bone resorption [serum C-telopeptides (CTx)] were measured. From a random coefficients model, we constructed estimates and confidence intervals for all outcomes. RESULTS BSAP decreased by 2.8% per day in the placebo arm (p = 0.03) but remained stable in the LMMS group (p = 0.51, pdiff = 0.04). CTx did not change with placebo (p = 0.56) but increased in the LMMS arm (+6.2% per day, p = 0.04; pdiff = 0.01). Serum OC did not change in either group (p > 0.70). CONCLUSIONS Bed rest during hospitalization for patients with AN is associated with a suppression of bone turnover, which may contribute to diminished bone quality. Brief, daily LMMS prevents a decline in bone turnover during bed rest in AN. Protocols prescribing strict bed rest may not be appropriate for protecting bone health for these patients. LMMS may have application for these patients in the inpatient setting.
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Affiliation(s)
- A D DiVasta
- Division of Adolescent Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
- Division of Gynecology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA.
| | - H A Feldman
- Clinical Research Program, Boston Children's Hospital, Boston, MA, USA
| | - C T Rubin
- Department of Biomedical Engineering, State University of New York Stony Brook, Stony Brook, NY, USA
| | - J S Gallagher
- Division of Adolescent Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - N Stokes
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - D P Kiel
- Institute for Aging Research, Hebrew SeniorLife, Roslindale, MA, USA
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - B D Snyder
- Department of Orthopedic Surgery, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - C M Gordon
- Division of Adolescent and Transition Medicine, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Youn JC, Lee SJ, Lee HS, Oh J, Hong N, Park S, Lee SH, Choi D, Rhee Y, Kang SM. Exercise capacity independently predicts bone mineral density and proximal femoral geometry in patients with acute decompensated heart failure. Osteoporos Int 2015; 26:2121-9. [PMID: 25963233 DOI: 10.1007/s00198-015-3112-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/17/2015] [Indexed: 10/23/2022]
Abstract
UNLABELLED Heart failure is associated with increased risk of osteoporosis. We evaluated the prevalence and predictors of osteoporosis in hospitalized patients with ADHF using quantitative computed tomography. Osteoporosis and vertebral fracture are prevalent in patients with ADHF and exercise capacity independently predicts bone mass and femoral bone geometry. INTRODUCTION Heart failure is associated with reduced bone mass and increased risk of osteoporotic fractures. However, the prevalence and predictors of osteoporosis in hospitalized patients with acute decompensated heart failure (ADHF) are not well understood. METHODS Sixty-five patients (15 postmenopausal females and 50 males) with ADHF were prospectively and consecutively enrolled. After stabilization of heart failure symptoms, quantitative computed tomography for bone mineral density (BMD) and femoral geometry as well as biochemical, echocardiographic, and cardiopulmonary exercise tests were performed. RESULTS Fifteen postmenopausal female showed a high prevalence of osteoporosis (40%) and vertebral fracture (53%). Among 50 male patients, 12% had osteoporosis and 32% had osteopenia, while vertebral fracture was found in 12%. Lumbar volumetric BMD (vBMD) was significantly lower in ischemic patients than non-ischemic patients (107.9 ± 47.5 vs. 145.4 ± 40.9 mg/cm(3), p = 0.005) in male. Exercise capacity, indicated by peak oxygen consumption (VO2), was significantly associated with lumbar vBMD (r = 0.576, p < 0.001) and total hip areal BMD (aBMD) (r = 0.512, p = 0.001) and cortical thickness of the femur neck (r = 0.544, p = 0.001). When controlled for age, body mass index, N-terminal proBrain natriuretic protein (NT-proBNP), etiology of heart failure, hemoglobin, and thigh circumference, multivariate regression analysis revealed peak VO2 independently predicted lumbar vBMD (β = 0.448, p = 0.031), total hip aBMD (β = 0.547, p = 0.021), and cortical thickness of the femur neck (β = 0.590, p = 0.011). CONCLUSION In male patients with ADHF, osteoporosis and vertebral fracture are prevalent, and exercise capacity independently predicts bone mass and geometry. Given that heart failure patients with reduced exercise capacity carry a substantial increased risk of fracture, proper osteoporosis evaluation is important in these patients.
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Affiliation(s)
- J-C Youn
- Division of Cardiology, Severance Cardiovascular Hospital and Cardiovascular Research Institute, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea
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Khajuria DK, Razdan R, Mahapatra DR. Effect of combined treatment with zoledronic acid and propranolol on mechanical strength in an rat model of disuse osteoporosis. REVISTA BRASILEIRA DE REUMATOLOGIA 2014; 55:501-11. [PMID: 25480532 DOI: 10.1016/j.rbr.2014.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/12/2014] [Accepted: 07/28/2014] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVES A model that uses right hind-limb unloading of rats is used to study the consequences of skeletal unloading during various conditions like space flights and prolonged bed rest in elderly. This study was aimed to investigate the additive effects of antiresorptive agent zoledronic acid (ZOL), alone and in combination with propranolol (PRO) in a rat model of disuse osteoporosis. METHODS In the present study, 3-month-old male Wistar rats had their right hind-limb immobilized (RHLI) for 10 weeks to induce osteopenia, then were randomized into four groups: 1- RHLI positive control, 2- RHLI plus ZOL (50 μg/kg, i.v. single dose), 3- RHLI plus PRO (0.1mg/kg, s.c. 5 days per week), 4- RHLI plus PRO (0.1mg/kg, s.c. 5 days per week) plus ZOL (50 μg/kg, i.v. single dose) for another 10 weeks. One group of non-immobilized rats was used as negative control. At the end of treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and bone dry and ash weight. RESULTS With respect to improvement in the mechanical strength of the femoral mid-shaft, the combination treatment with ZOL plus PRO was more effective than ZOL or PRO monotherapy. Moreover, combination therapy using ZOL plus PRO was more effective in improving dry bone weight and preserved the cortical bone porosity better than monotherapy using ZOL or PRO in right hind-limb immobilized rats. CONCLUSIONS These data suggest that this combined treatment with ZOL plus PRO should be recommended for the treatment of disuse osteoporosis.
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Affiliation(s)
- Deepak Kumar Khajuria
- Departamento de Farmacologia, Al-Ameen College of Pharmacy, Bangalore, India; Laboratório de Integrativas Multiscale Materiais e Engenharia de Sistemas, Departamento de Engenharia Aeroespacial, Indian Institute of Science, Bangalore, India.
| | - Rema Razdan
- Departamento de Farmacologia, Al-Ameen College of Pharmacy, Bangalore, India
| | - Debiprosad Roy Mahapatra
- Laboratório de Integrativas Multiscale Materiais e Engenharia de Sistemas, Departamento de Engenharia Aeroespacial, Indian Institute of Science, Bangalore, India
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Khajuria DK, Disha C, Razdan R, Mahapatra DR, Vasireddi R. Prophylactic Effects of Propranolol versus the Standard Therapy on a New Model of Disuse Osteoporosis in Rats. Sci Pharm 2013; 82:357-74. [PMID: 24959400 PMCID: PMC4065128 DOI: 10.3797/scipharm.1310-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 12/09/2013] [Indexed: 11/22/2022] Open
Abstract
Disuse by bed rest, limb immobilization, or space flight causes rapid bone loss by arresting bone formation and accelerating bone resorption. Propranolol (a non-selective β-adrenergic antagonist) has been shown to improve bone properties by increasing bone formation and decreasing bone resorption in an ovariectomy-induced rat model. However, no studies have yet compared the osteoprotective properties of propranolol with well-accepted therapeutic interventions for the treatment and prevention of immobilization/disuse osteoporosis. To clarify this, we investigated the effects of propranolol compared with zoledronic acid and alfacalcidol in a new animal model of immobilization/disuse osteoporosis. Three-month-old male Wistar rats were divided into five groups with six animals in each group: (1) immobilized (IMM) control; (2) normal control; (3) IMM + zoledronic acid (50 μg/kg, intravenous single dose); (4) IMM + alfacalcidol (0.5 μg/kg, per oral daily); (5) IMM + propranolol (0.1 mg/kg, subcutaneously 5 days/week) for 10 weeks. In groups 1 and 3-5, the right hindlimb was immobilized. At the end of treatment, the femurs were removed and tested for bone porosity, bone mechanical properties, and cortical microarchitecture. Treatment with propranolol induced greater reductions in the bone porosity of the right femur and improved the mechanical properties of the femoral mid-shaft femur in comparison to the IMM control. Moreover, treatment with propranolol also improved the microarchitecture of cortical bones when compared with the IMM control, as indicated by scanning electron microscopy. The anti-osteoporotic property of propranolol was comparable with zoledronic acid and alfacalcidol. This study shows that the bone resorption induced by immobilization/disuse in rats can be suppressed by treatment with propranolol.
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Affiliation(s)
- Deepak Kumar Khajuria
- Department of Pharmacology, Al-Ameen College of Pharmacy, Bangalore, India. ; Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India
| | - Choudhary Disha
- Department of Pharmacology, Al-Ameen College of Pharmacy, Bangalore, India
| | - Rema Razdan
- Department of Pharmacology, Al-Ameen College of Pharmacy, Bangalore, India
| | - D Roy Mahapatra
- Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India
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DiVasta AD, Gordon CM. Exercise and bone: where do we stand? Metabolism 2013; 62:1714-7. [PMID: 24140089 DOI: 10.1016/j.metabol.2013.09.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 09/17/2013] [Accepted: 09/17/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Amy D DiVasta
- Division of Adolescent and Young Adult Medicine, Boston Children's Hospital, 333 Longwood Avenue, Boston, MA 02115, USA; Division of Pediatric and Adolescent Gynecology, Boston Children's Hospital, Boston, MA 02115, USA.
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Weremko D, Skiba G, Raj S, Fandrejewski H. The effects of feed and protein restriction between 90 and 118 days of age on performance, bone growth and mineralization of pigs reared to 168 days of age. Anim Feed Sci Technol 2013. [DOI: 10.1016/j.anifeedsci.2013.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Ryan W, Lynch P, O'Doherty J. Compensatory effect of dietary phosphorus on performance of growing pigs and development of bone mineral density assessed using dual energy X-ray absorptiometry. Livest Sci 2011. [DOI: 10.1016/j.livsci.2010.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Wynnyckyj C, Omelon S, Willett T, Kyle K, Goldberg H, Grynpas M. Mechanism of bone collagen degradation due to KOH treatment. Biochim Biophys Acta Gen Subj 2011; 1810:192-201. [DOI: 10.1016/j.bbagen.2010.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 09/03/2010] [Accepted: 10/08/2010] [Indexed: 11/30/2022]
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10
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Shen WW, Zhao JH. Pulsed electromagnetic fields stimulation affects BMD and local factor production of rats with disuse osteoporosis. Bioelectromagnetics 2010; 31:113-9. [PMID: 19670410 DOI: 10.1002/bem.20535] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Pulsed electromagnetic fields (PEMF) have been used widely to treat nonunion fractures and related problems in bone healing, as a biological and physical method. With the use of Helmholtz coils and PEMF stimulators to generate uniform time-varying electromagnetic fields, the effects of extremely low frequency electromagnetic fields on bone mineral density (BMD) and local factor production in disuse osteoporosis (DOP) rats were investigated. Eighty 4-month-old female Sprague Dawley (SD) rats were randomly divided into intact (INT) group, DOP group, calcitonin-treated (CT) group, and PEMF stimulation group. The right hindlimbs of all the rats were immobilized by tibia-tail fixation except for those rats in the INT group. Rats in the CT group were injected with calcitonin (2 IU/kg, i.p., once a day) and rats in the PEMF group were irradiated with PEMF immediately postoperative. The BMD, serum transforming growth factor-beta 1 (TGF-beta1), and interleukin-6 (IL-6) concentration of the proximal femur were measured 1, 2, 4, and 8 weeks after treatment. Compared with the CT and DOP groups, the BMD and serum TGF-beta1 concentration in the PEMF group increased significantly after 8 weeks. The IL-6 concentration in the DOP group was elevated significantly after operation. The PEMF group showed significantly lower IL-6 level than the DOP group. The results found demonstrate that PEMF stimulation can efficiently suppress bone mass loss. We, therefore, conclude that PEMF may affect bone remodeling process through promoting TGF-beta1 secretion and inhibiting IL-6 expression.
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Affiliation(s)
- Wei-Wei Shen
- Department of Orthopaedics, Third Affiliated Daping Hospital, Research Institute of Surgery, Third Military Medical University, Chongqing, PR China
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Utz JC, Nelson S, O'Toole BJ, van Breukelen F. Bone strength is maintained after 8 months of inactivity in hibernating golden-mantled ground squirrels, Spermophilus lateralis. ACTA ACUST UNITED AC 2009; 212:2746-52. [PMID: 19684206 DOI: 10.1242/jeb.032854] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Prolonged inactivity leads to disuse atrophy, a loss of muscle and bone mass. Hibernating mammals are inactive for 6-9 months per year but must return to full activity immediately after completing hibernation. This necessity for immediate recovery presents an intriguing conundrum, as many mammals require two to three times the period of inactivity to recover full bone strength. Therefore, if hibernators experience typical levels of bone disuse atrophy during hibernation, there would be inadequate time available to recover during the summer active season. We examined whether there were mechanical consequences as a result of the extended inactivity of hibernation. We dissected femur and tibia bones from squirrels in various stages of the annual hibernation cycle and measured the amount of force required to fracture these bones. Three groups were investigated; summer active animals were captured during the summer and immediately killed, animals in the 1 month detraining group were captured in the summer and killed following a 1-month period of restricted mobility, hibernating animals were killed after 8 months of inactivity. A three-point bend test was employed to measure the force required to break the bones. Apparent flexural strength and apparent flexural modulus (material stiffness) were calculated for femurs. There were no differences between groups for femur fracture force, tibia fracture force, or femur flexural strength. Femur flexural modulus was significantly less for the 1 month detraining group than for the hibernation and summer active groups. Thus, hibernators seem resistant to the deleterious effects of prolonged inactivity during the winter. However, they may be susceptible to immobilization-induced bone loss during the summer.
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Affiliation(s)
- Jenifer C Utz
- School of Life Sciences, University of Nevada at Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, USA
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DiVasta AD, Feldman HA, Quach AE, Balestrino M, Gordon CM. The effect of bed rest on bone turnover in young women hospitalized for anorexia nervosa: a pilot study. J Clin Endocrinol Metab 2009; 94:1650-5. [PMID: 19223524 PMCID: PMC2684474 DOI: 10.1210/jc.2008-1654] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Malnourished adolescents with anorexia nervosa (AN) requiring medical hospitalization are at high risk for skeletal insults. Even short-term bed rest may further disrupt normal patterns of bone turnover. OBJECTIVE The objective of the study was to determine the effect of relative immobilization on bone turnover in adolescents hospitalized for AN. DESIGN This was a short-term observational study. SETTING The study was conducted at a tertiary care pediatric hospital. STUDY PARTICIPANTS Twenty-eight adolescents with AN, aged 13-21 yr with a mean body mass index of 15.9 +/- 1.8 kg/m(2), were enrolled prospectively on admission. INTERVENTION As per standard care, all subjects were placed on bed rest and graded nutritional therapy. MAIN OUTCOME MEASURE Markers of bone formation (bone specific alkaline phosphatase), turnover (osteocalcin), and bone resorption (urinary N-telopeptides NTx) were measured. RESULTS During the 5 d of hospitalization, serum osteocalcin increased by 0.24 +/- 0.1 ng/ml . d (P = 0.02). Urine N-telopeptides reached a nadir on d 3, declining -6.9 +/- 2.8 nm bone collagen equivalent per millimole creatinine (P = 0.01) but returned to baseline by d 5 (P > 0.05). Bone-specific alkaline phosphatase exhibited a decline that was strongly age dependent, being highly significant for younger subjects only [age 14 yr: -0.42 +/- 0.11 (P = 0.0002); age 18 yr: -0.03 +/- 0.08 (P = 0.68)]. Age had no effect on other outcome measures. CONCLUSION Limitation of physical activity during hospitalization for patients with AN is associated with suppressed bone formation and resorption and an imbalance of bone turnover. Future interventional studies involving mechanical stimulation and/or weight-bearing activity are needed to determine whether medical protocols prescribing strict bed rest are appropriate.
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Affiliation(s)
- Amy D DiVasta
- Division of Adolescent Medicine, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
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Thermostability of bone tissue after immobilization induced osteopenia in a rat model. Folia Histochem Cytobiol 2008; 46:379-82. [DOI: 10.2478/v10042-008-0043-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Portinho D, Boin VG, Bertolini GRF. Efeitos sobre o tecido ósseo e cartilagem articular provocados pela imobilização e remobilização em ratos Wistar. REV BRAS MED ESPORTE 2008. [DOI: 10.1590/s1517-86922008000500001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Longos períodos de imobilização conduzem à perda óssea e de propriedades do osso, e sua recuperação depende de vários fatores; além disso, a imobilização pode causar ulcerações no tecido cartilaginoso articular devido a alterações como perda de proteoglicanas, de massa e volume totais da cartilagem. O objetivo deste estudo foi verificar alterações histológicas, do tecido ósseo periarticular e da cartilagem articular, provocadas pela imobilização e remobilização de membros posteriores de ratos Wistar. Foram utilizados 12 ratos Wistar, divididos em dois grupos: GI - (n = 6): 15 dias com o membro posterior esquerdo imobilizado em plantiflexão, sendo o membro direito o controle; GR - (n = 6): período de 15 dias de remobilização livre na gaiola, associado a três séries diárias de alongamento do músculo sóleo esquerdo por 30 segundos. Foram avaliados no tecido ósseo as medidas de espessura do osso cortical, diâmetro do canal medular e número de osteócitos; no tecido cartilaginoso, foram mensurados a espessura média da cartilagem e o número de condrócitos. Como resultado, observou-se que para GI não houve alterações significativas na espessura do osso (p = 0,1156) nem no diâmetro do canal medular (p = 0,5698), mas diminuição significativa dos osteócitos em relação ao contralateral (p = 0,0005); em GR também houve decréscimo no número de osteócitos (p = 0,0001), mas as diferenças na espessura (p = 0,1343) e diâmetro do canal medular (p = 0,6456) mantiveram-se não significantes. Para os dados de cartilagem articular não houve diferenças significativas para as amostras, tanto na espessura da cartilagem para GI (p = 0,6640) e GR (p = 0,1633), quanto no número de condrócitos em GI (p = 0,9429) e GR (p = 0,1634). Conclui-se que duas semanas de imobilização e remobilização produziram apenas diminuição significativa no número de osteócitos nos ratos imobilizados; esse número continuou a diminuir mesmo nos animais remobilizados.
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Trebacz H, Zdunek A. Three-point bending and acoustic emission study of adult rat femora after immobilization and free remobilization. J Biomech 2006; 39:237-45. [PMID: 16321625 DOI: 10.1016/j.jbiomech.2004.10.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2003] [Accepted: 10/13/2004] [Indexed: 11/18/2022]
Abstract
The experiment concerned effects of immobilization and remobilization on mechanical properties of femoral shaft. Twenty-four weeks old male rats were used: two groups (I3 and I3R4) with the right hindlimb immobilized for 3 weeks by taping, and one control (C). In I3R4 immobilization was followed by 4 weeks of free remobilization. Mechanical properties in three-point bending, mass, geometry, and mineralization of bone tissue were measured post mortem in both femora in I3 and I3R4 and in right femora in control. Acoustic emission signals (AE) were recorded during the bending test. The right femora in I3, I3R4 and C did not differ significantly in size, mass and mineralization (ANOVA). The differences were significant considering mechanical parameters and AE signals. In I3 yield bending moment and stiffness were lower (p=0.013 and 0.025) and deflection was larger (p=0.030) than in C. In I3R4 maximum bending moment, yield moment, stiffness and work to failure were lower than in C (p=0.013, 0.009, 0.032, and 0.005). Paired t-test showed that remobilization resulted in worsening of properties of right femora. Side-to-side differences in I3R4 were more pronounced than in I3. Moreover, AE signals from the right femora were more numerous and burst type than from the left. The results demonstrate that strength of bone decreases during the first period of free remobilization. The decrease is accompanied by a significant decrease of bone toughness. The AE data support the hypothesis that immobilization-related degradation of bone mechanical properties is associated with increasing brittleness of cortical bone tissue.
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Affiliation(s)
- Hanna Trebacz
- Department of Biophysics, Medical University of Lublin, Al. Racławickie 1, Poland.
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Donahue SW, McGee ME, Harvey KB, Vaughan MR, Robbins CT. Hibernating bears as a model for preventing disuse osteoporosis. J Biomech 2005; 39:1480-8. [PMID: 15975583 DOI: 10.1016/j.jbiomech.2005.03.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2004] [Accepted: 03/26/2005] [Indexed: 11/22/2022]
Abstract
The hibernating bear is an excellent model for disuse osteoporosis in humans because it is a naturally occurring large animal model. Furthermore, bears and humans have similar lower limb skeletal morphology, and bears walk plantigrade like humans. Black bears (Ursus americanus) may not develop disuse osteoporosis during long periods of disuse (i.e. hibernation) because they maintain osteoblastic bone formation during hibernation. As a consequence, bone volume, mineral content, porosity, and strength are not adversely affected by annual periods of disuse. In fact, cortical bone bending strength has been shown to increase with age in hibernating black bears without a significant change in porosity. Other animals require remobilization periods 2-3 times longer than the immobilization period to recover the bone lost during disuse. Our findings support the hypothesis that black bears, which hibernate for as long as 5-7 months annually, have evolved biological mechanisms to mitigate the adverse effects of disuse on bone porosity and strength.
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Affiliation(s)
- Seth W Donahue
- Department of Biomedical Engineering, Michigan Technological University, 309 Minerals and Materials Engineering Building, 1400 Townsend Drive, Houghton, MI 49931, USA.
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Donahue SW, Vaughan MR, Demers LM, Donahue HJ. Bone formation is not impaired by hibernation (disuse) in black bears Ursus americanus. J Exp Biol 2003; 206:4233-9. [PMID: 14581593 DOI: 10.1242/jeb.00671] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SUMMARY
Disuse by bed rest, limb immobilization or space flight causes rapid bone loss by arresting bone formation and accelerating bone resorption. This net bone loss increases the risk of fracture upon remobilization. Bone loss also occurs in hibernating ground squirrels, golden hamsters, and little brown bats by arresting bone formation and accelerating bone resorption. There is some histological evidence to suggest that black bears Ursus americanus do not lose bone mass during hibernation (i.e. disuse). There is also evidence suggesting that muscle mass and strength are preserved in black bears during hibernation. The question of whether bears can prevent bone loss during hibernation has not been conclusively answered. The goal of the current study was to further assess bone metabolism in hibernating black bears. Using the same serum markers of bone remodeling used to evaluate human patients with osteoporosis, we assayed serum from five black bears, collected every 10 days over a 196-day period, for bone resorption and formation markers. Here we show that bone resorption remains elevated over the entire hibernation period compared to the pre-hibernation period, but osteoblastic bone formation is not impaired by hibernation and is rapidly accelerated during remobilization following hibernation.
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Affiliation(s)
- Seth W Donahue
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, USA.
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