51
|
Baldock PA, Lin S, Zhang L, Karl T, Shi Y, Driessler F, Zengin A, Hörmer B, Lee NJ, Wong IPL, Lin EJD, Enriquez RF, Stehrer B, During MJ, Yulyaningsih E, Zolotukhin S, Ruohonen ST, Savontaus E, Sainsbury A, Herzog H. Neuropeptide y attenuates stress-induced bone loss through suppression of noradrenaline circuits. J Bone Miner Res 2014; 29:2238-49. [PMID: 24535841 DOI: 10.1002/jbmr.2205] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 02/09/2014] [Accepted: 02/12/2014] [Indexed: 12/23/2022]
Abstract
Chronic stress and depression have adverse consequences on many organ systems, including the skeleton, but the mechanisms underlying stress-induced bone loss remain unclear. Here we demonstrate that neuropeptide Y (NPY), centrally and peripherally, plays a critical role in protecting against stress-induced bone loss. Mice lacking the anxiolytic factor NPY exhibit more anxious behavior and elevated corticosterone levels. Additionally, following a 6-week restraint, or cold-stress protocol, Npy-null mice exhibit three-fold greater bone loss compared to wild-type mice, owing to suppression of osteoblast activity. This stress-protective NPY pathway acts specifically through Y2 receptors. Centrally, Y2 receptors suppress corticotropin-releasing factor expression and inhibit activation of noradrenergic neurons in the paraventricular nucleus. In the periphery, they act to control noradrenaline release from sympathetic neurons. Specific deletion of arcuate Y2 receptors recapitulates the Npy-null stress response, coincident with elevated serum noradrenaline. Importantly, specific reintroduction of NPY solely in noradrenergic neurons of otherwise Npy-null mice blocks the increase in circulating noradrenaline and the stress-induced bone loss. Thus, NPY protects against excessive stress-induced bone loss, through Y2 receptor-mediated modulation of central and peripheral noradrenergic neurons.
Collapse
Affiliation(s)
- P A Baldock
- Neurological Disease Division, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia; Osteoporosis and Bone Biology Division, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia; Faculty of Medicine, University of New South Wales, Sydney, Australia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
52
|
Cao H, Kou X, Yang R, Liu D, Wang X, Song Y, Feng L, He D, Gan Y, Zhou Y. Force-induced Adrb2 in periodontal ligament cells promotes tooth movement. J Dent Res 2014; 93:1163-9. [PMID: 25252876 DOI: 10.1177/0022034514551769] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The sympathetic nervous system (SNS) regulates bone resorption through β-2 adrenergic receptor (Adrb2). In orthodontic tooth movement (OTM), mechanical force induces and regulates alveolar bone remodeling. Compressive force-associated osteoclast differentiation and alveolar bone resorption are the rate-limiting steps of tooth movement. However, whether mechanical force can activate Adrb2 and thus contribute to OTM remains unknown. In this study, orthodontic nickel-titanium springs were applied to the upper first molars of rats and Adrb1/2(-/-) mice to confirm the role of SNS and Adrb2 in OTM. The results showed that blockage of SNS activity in the jawbones of rats by means of superior cervical ganglion ectomy reduced OTM distance from 860 to 540 μm after 14 d of force application. In addition, the injection of nonselective Adrb2 agonist isoproterenol activated the downstream signaling of SNS to accelerate OTM from 300 to 540 μm after 7 d of force application. Adrb1/2(-/-) mice showed significantly reduced OTM distance (19.5 μm) compared with the wild-type mice (107.6 μm) after 7 d of force application. Histopathologic analysis showed that the number of Adrb2-positive cells increased in the compressive region of periodontal ligament after orthodontic force was applied on rats. Mechanistically, mechanical compressive force upregulated Adrb2 expression in primary-cultured human periodontal ligament cells (PDLCs) through the elevation of intracellular Ca(2+) concentration. Activation of Adrb2 in PDLCs increased the RANKL/OPG ratio and promoted the peripheral blood mononuclear cell differentiation to osteoclasts in the cocultured system. Upregulation of Adrb2 in PDLCs promoted osteoclastogenesis, which accelerated OTM through Adrb2-enhanced bone resorption. In summary, this study suggests that mechanical force-induced Adrb2 activation in PDLCs contributes to SNS-regulated OTM.
Collapse
Affiliation(s)
- H Cao
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| | - X Kou
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| | - R Yang
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| | - D Liu
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| | - X Wang
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| | - Y Song
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| | - L Feng
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| | - D He
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| | - Y Gan
- Center for Temporomandibular Disorders and Orofacial Pain, Peking University School and Hospital of Stomatology, Beijing, China
| | - Y Zhou
- Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration
| |
Collapse
|
53
|
Elefteriou F, Campbell P, Ma Y. Control of bone remodeling by the peripheral sympathetic nervous system. Calcif Tissue Int 2014; 94:140-51. [PMID: 23765388 PMCID: PMC3883940 DOI: 10.1007/s00223-013-9752-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 05/15/2013] [Indexed: 12/21/2022]
Abstract
The skeleton is no longer seen as a static, isolated, and mostly structural organ. Over the last two decades, a more complete picture of the multiple functions of the skeleton has emerged, and its interactions with a growing number of apparently unrelated organs have become evident. The skeleton not only reacts to mechanical loading and inflammatory, hormonal, and mineral challenges, but also acts of its own accord by secreting factors controlling the function of other tissues, including the kidney and possibly the pancreas and gonads. It is thus becoming widely recognized that it is by nature an endocrine organ, in addition to a structural organ and site of mineral storage and hematopoiesis. Consequently and by definition, bone homeostasis must be tightly regulated and integrated with the biology of other organs to maintain whole body homeostasis, and data uncovering the involvement of the central nervous system (CNS) in the control of bone remodeling support this concept. The sympathetic nervous system (SNS) represents one of the main links between the CNS and the skeleton, based on a number of anatomic, pharmacologic, and genetic studies focused on β-adrenergic receptor (βAR) signaling in bone cells. The goal of this report was to review the data supporting the role of the SNS and βAR signaling in the regulation of skeletal homeostasis.
Collapse
Affiliation(s)
- Florent Elefteriou
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt Center for Bone Biology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA,
| | | | | |
Collapse
|
54
|
Toulis KA, Hemming K, Stergianos S, Nirantharakumar K, Bilezikian JP. β-Adrenergic receptor antagonists and fracture risk: a meta-analysis of selectivity, gender, and site-specific effects. Osteoporos Int 2014; 25:121-9. [PMID: 24114396 DOI: 10.1007/s00198-013-2498-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 08/12/2013] [Indexed: 10/26/2022]
Abstract
UNLABELLED By meta-analysis, the risk of fracture was 15% lower in patients treated with β-adrenergic blockers compared to controls independent of gender, fracture site, and dose. This might be attributable to β1-selective blockers. INTRODUCTION The aim of this study is to determine by meta-analysis whether β-adrenergic blockers (BBs) reduce fracture risk and whether the effect, if demonstrable, is dependent upon selectivity, dose, gender, or fracture site. METHODS A literature search was performed in electronic databases MEDLINE, EMBASE, and reference sections of relevant articles to identify eligible studies. Adjusted estimates of fracture risk effect size (ES) were pooled across studies using fixed or random-effects (RE) meta-analysis as appropriate. Dose-related effects were evaluated using meta-regression. To explore the relative efficacy of β1-selective blockers in comparison to nonselective BBs, adjusted indirect comparison was performed. RESULTS A total of 16 studies (7 cohort and 9 case-control studies), involving 1,644,570 subjects, were identified. The risk of any fracture was found to be significantly reduced in subjects receiving BBs as compared to control subjects (16 studies, RE pooled ES = 0.86, 95% CI 0.78-0.93; I(2) = 87 %). In a sensitivity analysis limited to those studies deemed to be most robust, the BB effect to reduce fracture risk was sustained (four studies, pooled ES = 0.79, 95% CI 0.67-0.94; I(2) = 96%). The risk of a hip fracture was lower in both women and men receiving BBs (women: pooled ES = 0.86, 95% CI 0.80-0.91; I(2) = 1% and men: pooled ES = 0.80, 95% CI 0.71-0.90; I(2) = 0%). Similar risk reductions were found for clinical vertebral and forearm fractures, although statistical significance was not reached. The reduction in risk did not appear to be dose-related (test for a linear trend p value 0.150). Using adjusted indirect comparisons, it was estimated that β1-selective agents were significantly more effective than nonselective BBs in reducing the risk of any fracture (six studies, β1-selective blockers vs. nonselective BBs: RE pooled ES = 0.82, 95% CI = 0.69-0.97). CONCLUSIONS The findings suggest that the risk of fracture is approximately 15% lower in patients treated with BBs compared to controls independent of gender, fracture site, and dose. This risk reduction might be associated with the effects of β1-selective blockers.
Collapse
Affiliation(s)
- K A Toulis
- Department of Endocrinology, 424 General Military Hospital, Ring Road, Efkarpia, P.O. Box 55535, Thessaloniki, Greece,
| | | | | | | | | |
Collapse
|
55
|
Roy B. Biomolecular basis of the role of diabetes mellitus in osteoporosis and bone fractures. World J Diabetes 2013; 4:101-113. [PMID: 23961320 PMCID: PMC3746082 DOI: 10.4239/wjd.v4.i4.101] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 06/04/2013] [Accepted: 07/18/2013] [Indexed: 02/05/2023] Open
Abstract
Osteoporosis has become a serious health problem throughout the world which is associated with an increased risk of bone fractures and mortality among the people of middle to old ages. Diabetes is also a major health problem among the people of all age ranges and the sufferers due to this abnormality increasing day by day. The aim of this review is to summarize the possible mechanisms through which diabetes may induce osteoporosis. Diabetes mellitus generally exerts its effect on different parts of the body including bone cells specially the osteoblast and osteoclast, muscles, retina of the eyes, adipose tissue, endocrine system specially parathyroid hormone (PTH) and estrogen, cytokines, nervous system and digestive system. Diabetes negatively regulates osteoblast differentiation and function while positively regulates osteoclast differentiation and function through the regulation of different intermediate factors and thereby decreases bone formation while increases bone resorption. Some factors such as diabetic neuropathy, reactive oxygen species, Vitamin D, PTH have their effects on muscle cells. Diabetes decreases the muscle strength through regulating these factors in various ways and ultimately increases the risk of fall that may cause bone fractures.
Collapse
|
56
|
Joyce NC, Hache LP, Clemens PR. Bone health and associated metabolic complications in neuromuscular diseases. Phys Med Rehabil Clin N Am 2012; 23:773-99. [PMID: 23137737 DOI: 10.1016/j.pmr.2012.08.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article reviews the recent literature regarding bone health as it relates to the patient living with neuromuscular disease (NMD). Studies defining the scope of bone-related disease in NMD are scant. The available evidence is discussed, focusing on abnormal calcium metabolism, increased fracture risk, and the prevalence of both scoliosis and hypovitaminosis D in Duchenne muscular dystrophy, amyotrophic lateral sclerosis, and spinal muscular atrophy. Future directions are discussed, including the urgent need for studies both to determine the nature and extent of poor bone health, and to evaluate the therapeutic effect of available osteoporosis treatments in patients with NMD.
Collapse
Affiliation(s)
- Nanette C Joyce
- Department of Rehabilitation Medicine, University of California, Davis, Sacramento, CA 95817, USA.
| | | | | |
Collapse
|
57
|
Yu H, Watt H, Kesavan C, Johnson PJ, Wergedal JE, Mohan S. Lasting consequences of traumatic events on behavioral and skeletal parameters in a mouse model for post-traumatic stress disorder (PTSD). PLoS One 2012; 7:e42684. [PMID: 22927935 PMCID: PMC3425500 DOI: 10.1371/journal.pone.0042684] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 07/11/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Post-traumatic stress disorder (PTSD) is an anxiety disorder that not only affects mental health, but may also affect bone health. However, there have been no studies to examine the direct relationship between PTSD and bone. METHODOLOGY/PRINCIPAL FINDINGS We employed electric shocks in mice to simulate traumatic events that cause PTSD. We also injected the anxiogenic drug FG-7142 prior to electric shocks. Electric shocks created lasting conditioned fear memory in all mice. In young mice, electric shocks elicited not only behavioral response but also skeletal response, and injection of FG-7142 appeared to increase both types of response. For example in behavioral response within the first week, mice shocked alone froze an average of 6.2 sec in 10 sec tests, and mice injected with FG-7142 froze 7.6 sec, both significantly different (P<0.05) from control mice, which only froze 1.3 sec. In skeletal response at week 2, shocks alone reduced 6% bone mineral content (BMC) in total body (P = 0.06), while shocks with FG-7142 injection reduced not only 11% BMC (P<0.05) but also 6% bone mineral density (BMD) (P<0.05). In addition, FG-7142 injection also caused significant reductions of BMC in specific bones such as femur, lumbar vertebra, and tibia at week 3. Strong negative correlations (R(2) = -0.56, P<0.05) and regression (y = 0.2527-0.0037 * x, P<0.01) between freezing behavior and total body BMC in young mice indicated that increased contextual PTSD-like behavior was associated with reduced bone mass acquisition. CONCLUSIONS/SIGNIFICANCE This is the first study to document evidence that traumatic events induce lasting consequences on both behavior and skeletal growth, and electric shocks coupled with injection of anxiogenic FG-7142 in young mice can be used as a model to study the effect of PTSD-like symptoms on bone development.
Collapse
Affiliation(s)
- Hongrun Yu
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - Heather Watt
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California, United States of America
| | - Chandrasekhar Kesavan
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - Patrick J. Johnson
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California, United States of America
| | - Jon E. Wergedal
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - Subburaman Mohan
- Musculoskeletal Disease Center, Jerry L. Pettis Memorial VA Medical Center, Loma Linda, California, United States of America
- Department of Medicine, Loma Linda University, Loma Linda, California, United States of America
- * E-mail:
| |
Collapse
|
58
|
Campbell JP, Karolak MR, Ma Y, Perrien DS, Masood-Campbell SK, Penner NL, Munoz SA, Zijlstra A, Yang X, Sterling JA, Elefteriou F. Stimulation of host bone marrow stromal cells by sympathetic nerves promotes breast cancer bone metastasis in mice. PLoS Biol 2012; 10:e1001363. [PMID: 22815651 PMCID: PMC3398959 DOI: 10.1371/journal.pbio.1001363] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 06/06/2012] [Indexed: 01/10/2023] Open
Abstract
The activation of sympathetic nerves by psychosocial stress creates a favorable environment in bone for the establishment of cancer cells in a mouse model of breast cancer. Bone and lung metastases are responsible for the majority of deaths in patients with breast cancer. Following treatment of the primary cancer, emotional and psychosocial factors within this population precipitate time to recurrence and death, however the underlying mechanism(s) remain unclear. Using a mouse model of bone metastasis, we provide experimental evidence that activation of the sympathetic nervous system, which is one of many pathophysiological consequences of severe stress and depression, promotes MDA-231 breast cancer cell colonization of bone via a neurohormonal effect on the host bone marrow stroma. We demonstrate that induction of RANKL expression in bone marrow osteoblasts, following β2AR stimulation, increases the migration of metastatic MDA-231 cells in vitro, independently of SDF1-CXCR4 signaling. We also show that the stimulatory effect of endogenous (chronic stress) or pharmacologic sympathetic activation on breast cancer bone metastasis in vivo can be blocked with the β-blocker propranolol, and by knockdown of RANK expression in MDA-231 cells. These findings indicate that RANKL promotes breast cancer cell metastasis to bone via its pro-migratory effect on breast cancer cells, independently of its effect on bone turnover. The emerging clinical implication, supported by recent epidemiological studies, is that βAR-blockers and drugs interfering with RANKL signaling, such as Denosumab, could increase patient survival if used as adjuvant therapy to inhibit both the early colonization of bone by metastatic breast cancer cells and the initiation of the “vicious cycle” of bone destruction induced by these cells. Improved detection programs and better drugs to eradicate breast tumors have increased survival in women with breast cancer. However, pain and metastasis to distant organs, including bone, remain significant clinical problems. Understanding why and how metastatic cancer cells colonize specific organs is therefore critical if we are to further improve morbidity and mortality for these patients. Using a mouse model of breast cancer bone metastasis, we present evidence that activation of sympathetic nerves, which is typical in chronic stress or depression, promotes the colonization and establishment of metastatic cancer cells within the bone marrow, leading to an increase in bone osteolytic lesions. We show that this effect is mediated via a β-adrenergic receptor-dependent response of the host bone marrow stroma to catecholamines, that are released upon sympathetic activation, and via the pro-migratory activity of RANKL, a cytokine that is well known to promote bone resorption. Of importance clinically, blocking sympathetic activation with a β-blocker, or blocking RANKL signaling in cancer cells, inhibited the stimulatory effect of sympathetic activation on bone metastasis in this mouse model. Stress-induced sympathetic activation may thus explain, at least in part, the reduced survival rate of breast cancer patients experiencing severe depression. The data also support the use of β-blockers or RANKL blockade as possible adjuvant therapy for women with breast cancer.
Collapse
Affiliation(s)
- J. Preston Campbell
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Matthew R. Karolak
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Yun Ma
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Daniel S. Perrien
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Orthopaedic Surgery and Rehabilitation, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, United States of America
| | - S. Kathryn Masood-Campbell
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Niki L. Penner
- Department of Medicine, Division of Allergy, Pulmonary, and Critical Care Medicine, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Steve A. Munoz
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Andries Zijlstra
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Xiangli Yang
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Julie A. Sterling
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Veterans Affairs (VISN 9), Nashville, Tennessee, United States of America
| | - Florent Elefteriou
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
- Vanderbilt Center for Bone Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Cancer Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
| |
Collapse
|
59
|
Doorn J, Leusink M, Groen N, van de Peppel J, van Leeuwen JPTM, van Blitterswijk CA, de Boer J. Diverse effects of cyclic AMP variants on osteogenic and adipogenic differentiation of human mesenchymal stromal cells. Tissue Eng Part A 2012; 18:1431-42. [PMID: 22646480 DOI: 10.1089/ten.tea.2011.0484] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Osteogenic differentiation of human mesenchymal stromal cells (hMSCs) may potentially be used in cell-based bone tissue-engineering applications to enhance the bone-forming potential of these cells. Osteogenic differentiation and adipogenic differentiation are thought to be mutually exclusive, and although several signaling pathways and cues that induce osteogenic or adipogenic differentiation, respectively, have been identified, there is no general consensus on how to optimally differentiate hMSCs into the osteogenic lineage. Some pathways have also been reported to be involved in both adipogenic and osteogenic differentiation, as for example, the protein kinase A (PKA) pathway, and the aim of this study was to investigate the role of cAMP/PKA signaling in differentiation of hMSCs in more detail. We show that activation of this pathway with dibutyryl-cAMP results in enhanced alkaline phosphatase expression, whereas another cAMP analog induces adipogenesis in long-term mineralization cultures. Adipogenic differentiation, induced by 8-bromo-cAMP, was accompanied by stronger PKA activity and higher expression of cAMP-responsive genes, suggesting that stronger activation correlates with adipogenic differentiation. In addition, a whole-genome expression analysis showed an increase in expression of adipogenic genes in 8-br-cAMP-treated cells. Furthermore, by means of quantitative polymerase chain reaction, we show differences in peroxisome proliferator-activated receptor-γ activation, either alone or in combination with dexamethasone, thus demonstrating differential effects of the PKA pathway, most likely depending on its mode of activation.
Collapse
Affiliation(s)
- Joyce Doorn
- Department of Tissue Regeneration, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
60
|
Lecka-Czernik B. Marrow fat metabolism is linked to the systemic energy metabolism. Bone 2012; 50:534-9. [PMID: 21757043 PMCID: PMC3197966 DOI: 10.1016/j.bone.2011.06.032] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/24/2011] [Accepted: 06/25/2011] [Indexed: 12/25/2022]
Abstract
Recent advances in understanding the role of bone in the systemic regulation of energy metabolism indicate that bone marrow cells, adipocytes and osteoblasts, are involved in this process. Marrow adipocytes store significant quantities of fat and produce adipokines, leptin and adiponectin, which are known for their role in the regulation of energy metabolism, whereas osteoblasts produce osteocalcin, a bone-specific hormone that has a potential to regulate insulin production in the pancreas and adiponectin production in fat tissue. Both osteoblasts and marrow adipocytes express insulin receptor and respond to insulin-sensitizing anti-diabetic TZDs in a manner, which tightly links bone with the energy metabolism system. Metabolic profile of marrow fat resembles that of both, white and brown fat, which is reflected by its plasticity in acquiring different functions including maintenance of bone micro-environment. Marrow fat responds to physiologic and pathologic changes in energy metabolism status by changing volume and metabolic activity. This review summarizes available information on the metabolic function of marrow fat and provides hypothesis that this fat depot may acquire multiple roles depending on the local and perhaps systemic demands. These functions may include a role in bone energy maintenance and endocrine activities to serve osteogenesis during bone remodeling and bone healing.
Collapse
Affiliation(s)
- Beata Lecka-Czernik
- Department of Orthopaedic Surgery, University of Toledo Health Sciences Campus, Toledo, OH 43614, USA.
| |
Collapse
|
61
|
Bone mineral density in spinal cord injury: an evaluation of the distal femur. J Osteoporos 2012; 2012:519754. [PMID: 22970408 PMCID: PMC3434402 DOI: 10.1155/2012/519754] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 07/09/2012] [Indexed: 12/21/2022] Open
Abstract
Osteoporosis (OP) in spinal cord injury (SCI) patients is a secondary process in which numerous factors are involved. Diagnosing OP and the threshold for fractures in this population, based on bone mineral density (BMD) measured by double energy X-ray absorptiometry (DXA), is still a challenge. The aim of this study was to evaluate bone mineral loss by DXA, its relationship with body composition and fracture incidence, in complete paraplegics patients, compared with aged-matched controls; we include a nonstandard bone site, the distal femur, and describe the technical and practical aspects of this procedure. Twenty-five SCI patients were included in the study and 17 subjects as control group. No prior or recent fractures were observed in X-ray analysis. The BMD of all femoral sites was significantly lower in patients than in controls (femoral neck, total femur, and distal femur); no difference was observed between BMD of the lumbar spine of patients and controls. We found inverse relationship between time of SCI and bone mineral mass only for distal femur BMD. We conclude that the distal femur is a more sensitive bone site for assessing bone loss by DXA, in SCI patients, than the proximal femoral sites.
Collapse
|