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Kassem AA, Issa DAE, Kotry GS, Farid RM. Thiolated alginate-based multiple layer mucoadhesive films of metformin forintra-pocket local delivery: in vitro characterization and clinical assessment. Drug Dev Ind Pharm 2016; 43:120-131. [PMID: 27589817 DOI: 10.1080/03639045.2016.1224895] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Periodontal disease broadly defines group of conditions in which the supportive structure of the tooth (periodontium) is destroyed. Recent studies suggested that the anti-diabetic drug metformin hydrochloride (MF) has an osteogenic effect and is beneficial for the management of periodontitis. OBJECTIVE Development of strong mucoadhesive multiple layer film loading small dose of MF for intra-pocket application. METHODOLOGY Multiple layer film was developed by double casting followed by compression method. Either 6% carboxy methyl cellulose sodium (CMC) or sodium alginate (ALG) constituted the inner drug (0.6%) loaded layer. Thiolated sodium alginate (TSA; 2 or 4%) constituted the outer drug free layers to enhance mucoadhesion and achieve controlled drug release. Optimized formulation was assessed clinically on 20 subjects. RESULTS Films were uniform, thin and hard enough for easy insertion into periodontal pockets. Based on water uptake and in vitro drug release, CMC based film with 4% TSA as an outer layer was the optimized formulation with enhanced mucoadhesion and controlled drug release (83.73% over 12 h). SEM showed the effective fabrication of the triple layer film in which connective lines between the layers could be observed. FTIR examination suggests possibility of hydrogen bonding between the -NH groups of metformin and -OH groups of CMC. DSC revealed the presence of MF mainly in the amorphous form. Clinical results indicated improvement of all clinical parameters six months post treatment. CONCLUSION The results suggested that local application of the mucoadhesive multiple layer films loaded with metformin hydrochloride was able to manage moderate chronic periodontitis.
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Affiliation(s)
- Abeer Ahmed Kassem
- a Department of Pharmaceutical Sciences, Faculty of Pharmacy , Princess Nourah bint Abdulrahman University , Riyadh , Saudi Arabia.,b Department of Pharmaceutics, Faculty of Pharmacy , Alexandria University , Alexandria , Egypt
| | - Doaa Ahmed Elsayed Issa
- c Department of Pharmaceutical Sciences, Faculty of Pharmacy , Beirut Arab University , Beirut , Lebanon.,d Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Alexandria University , Alexandria , Egypt
| | - Gehan Sherif Kotry
- e Department of Oral Medicine, Periodontology, Oral Diagnosis and Radiology, Faculty of Dentistry , Alexandria University , Alexandria , Egypt
| | - Ragwa Mohamed Farid
- f Department of Pharmaceutics, Faculty of Pharmacy and Drug Manufacturing , Pharos University in Alexandria , Alexandria , Egypt
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102
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Choi HJ, Park C, Lee YK, Ha YC, Jang S, Shin CS. Risk of fractures and diabetes medications: a nationwide cohort study. Osteoporos Int 2016; 27:2709-2715. [PMID: 27080708 DOI: 10.1007/s00198-016-3595-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 04/07/2016] [Indexed: 12/14/2022]
Abstract
UNLABELLED The effects of diabetes medications on risk of fracture were investigated using the South Korea nationwide claims database. We demonstrated that the use of dipeptidyl peptidase-4 inhibitor could be associated with decreased risk of fracture. Thiazolidinedione use was associated with about 60 % increased risk of fracture in real clinical practice. INTRODUCTION The effects of diabetes medication on fracture have important clinical health consequences, since most diabetes patients are at high risk of fracture. We aimed to investigate the effect of diabetes medication on fracture risk. METHODS The nationwide medical claim database in South Korea was investigated. Among 2,886,555 subjects with antidiabetes prescriptions, 207,558 subjects aged 50 years and older, who initiated diabetes medication from 2008 to 2011, were analyzed. The subjects were classified based on diabetes medication classes: non-user (insufficient exposure), metformin (MET), sulfonylurea (SU), alpha-glucosidase inhibitor (AGI), MET + SU, MET + thiazolidinedione (TZD), MET + dipeptidyl peptidase-4 inhibitor (DPP4-I), and SU + TZD. RESULTS A total of 5996 fractures were observed. The fracture rate varied significantly across type of diabetes medications, with MET + DPP4-I combination group having the lowest rate and SU + TZD combination group having the highest rate. Compared to non-users, MET + DPP4-I inhibitor combination group had significantly reduced composite fracture risk (hazard ratio (HR) = 0.83, P = 0.025) and significantly reduced vertebral fracture risk (HR = 0.73, P = 0.013) in the unadjusted analysis. Compared to MET + SU users, MET + DPP4-I users showed a trend of lower non-vertebral fracture risk (HR = 0.82, P = 0.086) after adjusting for all confounding variables. Patients using TZD had significantly increased risk of fracture (HR = 1.59, P < 0.001) compared with patients not using TZDs adjusting for all confounding variables. CONCLUSIONS The results of this nationwide study showed a trend that DPP4 inhibitor might have a protective effect on bone metabolism compared with SU, when added to MET. Clinicians should take these results into consideration when prescribing diabetes medication, especially in elderly patients or those at high risk or fracture.
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Affiliation(s)
- H J Choi
- Department of Anatomy, Seoul National University College of Medicine, Seoul, South Korea
| | - C Park
- Division for Healthcare Technology Assessment Research, National Evidence-based Healthcare Collaborating Agency, Seoul, South Korea
| | - Y-K Lee
- Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Y-C Ha
- Department of Orthopaedic Surgery, Chung-Ang University Hospital, Seoul, South Korea
| | - S Jang
- College of Pharmacy Gachon University, Incheon, South Korea
| | - C S Shin
- Department of Internal Medicine, Seoul National University College of Medicine, 28 Yungun-Dong, Chongno-Gu, Seoul, 110-744, South Korea.
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Bastos MF, Serrão CR, Miranda TS, Cruz DF, de Souza Malta F, Duarte PM. Effects of metformin on bone healing around titanium implants inserted in non-diabetic rats. Clin Oral Implants Res 2016; 28:e146-e150. [DOI: 10.1111/clr.12960] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Marta Ferreira Bastos
- Department of Periodontics; Dental Research Division; Guarulhos University; Guarulhos São Paulo Brazil
| | - Caroline Ribeiro Serrão
- Department of Periodontics; Dental Research Division; Guarulhos University; Guarulhos São Paulo Brazil
| | | | - Daniele Ferreira Cruz
- Department of Periodontics; Dental Research Division; Guarulhos University; Guarulhos São Paulo Brazil
| | - Fernando de Souza Malta
- Department of Periodontics; Dental Research Division; Guarulhos University; Guarulhos São Paulo Brazil
| | - Poliana Mendes Duarte
- Department of Periodontics; Dental Research Division; Guarulhos University; Guarulhos São Paulo Brazil
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Malhotra A. Letters to the Editor: Re: Platelet-Rich Fibrin With 1% Metformin for the Treatment of Intrabony Defects in Chronic Periodontitis: A Randomized Controlled Clinical Trial. J Periodontol 2016; 87:849. [DOI: 10.1902/jop.2016.150690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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105
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La Fontaine J, Chen C, Hunt N, Jude E, Lavery L. Type 2 Diabetes and Metformin Influence on Fracture Healing in an Experimental Rat Model. J Foot Ankle Surg 2016; 55:955-60. [PMID: 27286924 DOI: 10.1053/j.jfas.2016.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Indexed: 02/03/2023]
Abstract
Persons with diabetes have a greater incidence of fractures compared with persons without diabetes. However, very little published information is available concerning the deleterious effect of late-stage diabetes on osseous structure and bone healing. The purpose of the present study was to evaluate the role of diabetes on fracture healing in a rat femur repair model. Thirty-six lean and diabetic Zucker rats were subdivided into 3 groups: (1) 12 lean rats as the control group; (2) 12 diabetic rats without blood glucose control (DM group); and (3) 12 diabetic rats treated with 300 mg/kg metformin to reduce the blood glucose levels (DM + Met group). Radiographs were taken every week to determine the incidence of bone repair and delayed union. All the rats were killed at 6 weeks after surgery. In both the sham-operated and the fractured and repaired femurs, significant decreases in the fracture-load/weight and marginal decreases in the fracture-load between the lean and DM groups were found. Metformin treatment significantly reduced the blood glucose and body weight 12 days postoperatively. Furthermore, a decrease in the fracture-load and fracture-load/weight in the repaired femurs was found in the DM + Met group. Diabetes impairs bone fracture healing. Metformin treatment reduces the blood glucose and body weight but had an adverse effect on fracture repair in diabetic rats. Further investigations are needed to reveal the mechanisms responsible for the effects of type 2 diabetes mellitus on bone and bone quality and the effect of medications such as metformin might have in diabetic bone in the presence of neuropathy and vascular disease.
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Affiliation(s)
- Javier La Fontaine
- Associate Professor, Department of Plastic Surgery, University of Texas Southwestern Medical Center, Dallas, TX.
| | - Chris Chen
- Assistant Professor, Department of Orthopedics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Nathan Hunt
- Staff Podiatrist, Orthopaedic Center of the Rockies, Fort Collins, CO
| | - Edward Jude
- Consultant Physician/Diabetologist, Tameside General Hospital, Ashton-Under-Lyne, UK
| | - Lawrence Lavery
- Professor, Department of Plastic Surgery, University of Texas Southwestern Medical Center, Dallas, TX
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106
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Wang YG, Qu XH, Yang Y, Han XG, Wang L, Qiao H, Fan QM, Tang TT, Dai KR. AMPK promotes osteogenesis and inhibits adipogenesis through AMPK-Gfi1-OPN axis. Cell Signal 2016; 28:1270-1282. [PMID: 27283242 DOI: 10.1016/j.cellsig.2016.06.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 05/27/2016] [Accepted: 06/05/2016] [Indexed: 12/16/2022]
Abstract
Several metabolic, genetic and oncogenic bone diseases share the common pathological phenotype of defective bone marrow stromal cell (BMSC) differentiation. Many reports in bone science in the past several years have suggested that the skeleton also has an endocrine role. The role of AMP-activated protein kinase (AMPK) as an energy metabolism sensor and how it regulates BMSC differentiation is largely unknown. In the current study, we used AMPK agonists to activate AMPK in MC3T3-E1 cells to investigate the functional roles of AMPK in osteogenesis. However, metformin and AICAR failed to activate AMPK consistently. Therefore, we established MC3T3-E1 and 3T3-L1 cell models of AMPK α subunit overexpression through lentivirus vector, in which AMPK was overactivated. AMPK hyperactivation stimulated MC3T3-E1 cell osteogenesis and inhibited 3T3-L1 cell adipogenesis. Osteopontin (OPN) mediated AMPK regulation of osteogenesis and adipogenesis. Furthermore, we provided evidence that the transcriptional repressor growth factor independence-1 (Gfi1) was downregulated and disassociated from the OPN promoter in response to AMPK activation, resulting in the upregulation of OPN. Overexpression of wild-type and dominant-negative Gfi1 modulated MC3T3-E1 osteogenesis and 3T3-L1 adipogenesis. Further evidence suggested that AMPK enhanced ectopic bone formation of MC3T3-E1 cells through the AMPK-Gfi1-OPN axis. In conclusion, AMPK was sufficient to stimulate osteogenesis of MC3T3-E1 cells and inhibit adipogenesis of 3T3-L1 cells through the AMPK-Gfi1-OPN axis. These findings helped elucidate the molecular mechanisms underlying AMPK regulation of osteogenesis and adipogenesis.
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Affiliation(s)
- Yu-Gang Wang
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China
| | - Xin-Hua Qu
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China
| | - Ying Yang
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China
| | - Xiu-Guo Han
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China
| | - Lei Wang
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China
| | - Han Qiao
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China
| | - Qi-Ming Fan
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China.
| | - Ting-Ting Tang
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China.
| | - Ke-Rong Dai
- Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedic Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, People's Republic of China; The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai JiaoTong University School of Medicine (SJTUSM) & Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai 200025, China.
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107
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Metformin Decreases Reactive Oxygen Species, Enhances Osteogenic Properties of Adipose-Derived Multipotent Mesenchymal Stem Cells In Vitro, and Increases Bone Density In Vivo. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:9785890. [PMID: 27195075 PMCID: PMC4852347 DOI: 10.1155/2016/9785890] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/24/2016] [Accepted: 03/30/2016] [Indexed: 12/21/2022]
Abstract
Due to its pleiotropic effects, the commonly used drug metformin has gained renewed interest among medical researchers. While metformin is mainly used for the treatment of diabetes, recent studies suggest that it may have further application in anticancer and antiaging therapies. In this study, we investigated the proliferative potential, accumulation of oxidative stress factors, and osteogenic and adipogenic differentiation potential of mouse adipose-derived stem cells (MuASCs) isolated from mice treated with metformin for 8 weeks. Moreover, we investigated the influence of metformin supplementation on mice bone density and bone element composition. The ASCs isolated from mice who were treated with metformin for 8 weeks showed highest proliferative potential, generated a robust net of cytoskeletal projections, had reduced expression of markers associated with cellular senescence, and decreased amount of reactive oxygen species in comparison to control group. Furthermore, we demonstrated that these cells possessed greatest osteogenic differentiation potential, while their adipogenic differentiation ability was reduced. We also demonstrated that metformin supplementation increases bone density in vivo. Our result stands as a valuable source of data regarding the in vivo influence of metformin on ASCs and bone density and supports a role for metformin in regenerative medicine.
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108
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Increased risk of vertebral fracture in patients with diabetes: a meta-analysis of cohort studies. INTERNATIONAL ORTHOPAEDICS 2016; 40:1299-307. [DOI: 10.1007/s00264-016-3146-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Accepted: 02/16/2016] [Indexed: 12/31/2022]
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109
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Metformin alleviates vascular calcification induced by vitamin D3 plus nicotine in rats via the AMPK pathway. Vascul Pharmacol 2016; 81:83-90. [PMID: 26772768 DOI: 10.1016/j.vph.2016.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/08/2015] [Accepted: 01/01/2016] [Indexed: 12/18/2022]
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110
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Yokomoto-Umakoshi M, Kanazawa I, Takeno A, Tanaka KI, Notsu M, Sugimoto T. Activation of AMP-activated protein kinase decreases receptor activator of NF-κB ligand expression and increases sclerostin expression by inhibiting the mevalonate pathway in osteocytic MLO-Y4 cells. Biochem Biophys Res Commun 2016; 469:791-6. [DOI: 10.1016/j.bbrc.2015.12.072] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 01/01/2023]
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111
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Farr JN, Khosla S. Determinants of bone strength and quality in diabetes mellitus in humans. Bone 2016; 82:28-34. [PMID: 26211989 PMCID: PMC4679576 DOI: 10.1016/j.bone.2015.07.027] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 07/03/2015] [Accepted: 07/19/2015] [Indexed: 12/12/2022]
Abstract
There is growing evidence that the higher fracture rate observed in patients with type 2 diabetes mellitus (T2DM) is associated with normal, or even increased, areal bone mineral density (aBMD) by DXA. This has led to the hypothesis that patients with T2DM may have abnormalities in bone microarchitecture and/or material composition - i.e., key determinants of bone "quality." Consistent with this hypothesis, several studies using high-resolution peripheral quantitative computed tomography (HRpQCT) have demonstrated preserved indices of trabecular microarchitecture but increased cortical porosity in T2DM patients. In addition, a recent study using a novel in vivo microindentation device found an impairment in a measure of bone material properties (bone material strength index, BMSi) in postmenopausal women with longstanding T2DM; notably, the reduction in BMSi was associated with chronic glycemic control, suggesting that the skeleton should be included as another target organ subject to diabetic complications. The underlying pathogenesis of skeletal fragility in T2DM remains to be defined, although high levels of advanced glycation endproducts (AGEs) may play a role. In addition, T2DM is associated with reduced bone turnover, perhaps with an imbalance between bone resorption and bone formation. Although several studies have found increased serum sclerostin levels in patients with T2DM, the role of these increased levels in mediating the observed increases in cortical porosity or reduction in BMSi remains to be defined. Thus, although bone quality appears to be impaired in T2DM, the pathogenesis of these abnormalities and their relationship to the increased fracture risk observed in these patients needs further study.
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Affiliation(s)
- Joshua N Farr
- Endocrine Research Unit and Kogod Center on Aging, Mayo Clinic, Rochester, MN, USA.
| | - Sundeep Khosla
- Endocrine Research Unit and Kogod Center on Aging, Mayo Clinic, Rochester, MN, USA.
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112
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Pierrefite-Carle V, Santucci-Darmanin S, Breuil V, Camuzard O, Carle GF. Autophagy in bone: Self-eating to stay in balance. Ageing Res Rev 2015; 24:206-17. [PMID: 26318060 DOI: 10.1016/j.arr.2015.08.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 08/18/2015] [Accepted: 08/20/2015] [Indexed: 12/14/2022]
Abstract
Autophagy, a major catabolic pathway responsible of the elimination of damaged proteins and organelles, is now recognized as an anti-aging process. In addition to its basal role in cell homeostasis, autophagy is also a stress-responsive mechanism for survival purposes. Here, we review recent literature to highlight the autophagy role in the different bone cell types, i.e., osteoblasts, osteoclasts and osteocytes. We also discuss the effects of autophagy modulators in bone physiology and of bone anabolic compounds in autophagy. Finally, we analyzed studies regarding bone cell autophagy-deficient mouse models to obtain a more general view on how autophagy modulates bone physiology and pathophysiology, particularly during aging.
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Affiliation(s)
- Valérie Pierrefite-Carle
- UMR E-4320 TIRO-MATOs CEA/iBEB, Université Nice Sophia Antipolis, Faculté de Médecine Nice, France.
| | - Sabine Santucci-Darmanin
- UMR E-4320 TIRO-MATOs CEA/iBEB, Université Nice Sophia Antipolis, Faculté de Médecine Nice, France
| | - Véronique Breuil
- UMR E-4320 TIRO-MATOs CEA/iBEB, Université Nice Sophia Antipolis, Faculté de Médecine Nice, France; Service de Rhumatologie, CHU de Nice, Nice, France
| | - Olivier Camuzard
- UMR E-4320 TIRO-MATOs CEA/iBEB, Université Nice Sophia Antipolis, Faculté de Médecine Nice, France; Service de Chirurgie Réparatrice et de la main, CHU de Nice, Nice, France
| | - Georges F Carle
- UMR E-4320 TIRO-MATOs CEA/iBEB, Université Nice Sophia Antipolis, Faculté de Médecine Nice, France
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113
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Snacken M, Crenier L, Fery F, Praet JP, Pepersack T. Correlates of fractures in elderly, diabetic outpatients. Acta Clin Belg 2015; 70:331-8. [PMID: 25982152 DOI: 10.1179/2295333715y.0000000029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
It is widely recognized that patients presenting diabetes are at increased risk for fractures. In a retrospective case-control study, 101 cases were selected from medical charts of outpatients older than 70 with diabetes mellitus and a fracture within the past 5 years. Glycosylated hemoglobin (HbA1c) had been measured within 4 months around the assessment. Each case was matched for sex and age with one control, diabetic patient with no fracture. HbA1c level was similar in both groups. Patients with fractures presented significantly lower BMIs than controls, and had a higher rate of declared osteoporosis and comorbidity. A small number of cases were using vitamin D supplements while more were treated with benzodiazepine, opiates and Selective serotonin reuptake inhibitors (SSRI). This study suggests that, rather than the tight control of blood glucose, other factors such as medication and comorbidity could be associated with fracture risk in elderly diabetics.
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Affiliation(s)
- M Snacken
- Department of Geriatrics, Centre Hospitalier Universitaire Saint-Pierre, Université Libre de Bruxelles , Brussels, Belgium
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114
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Wang Y, Zhu G, Li N, Song J, Wang L, Shi X. Small molecules and their controlled release that induce the osteogenic/chondrogenic commitment of stem cells. Biotechnol Adv 2015; 33:1626-40. [PMID: 26341834 DOI: 10.1016/j.biotechadv.2015.08.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/21/2015] [Accepted: 08/23/2015] [Indexed: 12/17/2022]
Abstract
Stem cell-based tissue engineering plays a significant role in skeletal system repair and regenerative therapies. However, stem cells must be differentiated into specific mature cells prior to implantation (direct implantation may lead to tumour formation). Natural or chemically synthesised small molecules provide an efficient, accurate, reversible, and cost-effective way to differentiate stem cells compared with bioactive growth factors and gene-related methods. Thus, investigating the influences of small molecules on the differentiation of stem cells is of great significance. Here, we review a series of small molecules that can induce or/and promote the osteogenic/chondrogenic commitment of stem cells. The controlled release of these small molecules from various vehicles for stem cell-based therapies and tissue engineering applications is also discussed. The extensive studies in this field represent significant contributions to stem cell-based tissue engineering research and regenerative medicine.
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Affiliation(s)
- Yingjun Wang
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou 510640, PR China; School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Guanglin Zhu
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou 510640, PR China; School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Nanying Li
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou 510640, PR China; School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Juqing Song
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou 510640, PR China; School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Lin Wang
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou 510640, PR China; School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Xuetao Shi
- National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou 510640, PR China; School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, PR China.
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115
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Simpson C, Jayaramaraju D, Agraharam D, Gudipati S, Shanmuganathan R, Giannoudis PV. The effects of diabetes medications on post-operative long bone fracture healing. EUROPEAN JOURNAL OF ORTHOPAEDIC SURGERY AND TRAUMATOLOGY 2015; 25:1239-43. [PMID: 26319001 DOI: 10.1007/s00590-015-1691-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 08/08/2015] [Indexed: 01/29/2023]
Abstract
PURPOSE Diabetes has long been known to have an impact on bone repair. More recently, however, most diabetic patients receive medications to normalise this hyperglycaemic environment. To date, no studies have investigated the effects of diabetic medications on fracture healing in humans. METHOD Patients were identified from two tertiary trauma centres. Inclusion criteria were adult patients having sustained a closed diaphyseal femoral or tibial fracture, treated surgically. Exclusion criteria were open, pathological or peri-prosthetic fractures, and patients having sustained polytrauma. Matched non-diabetic controls were identified, matched for age, sex, fracture classification and osteosynthesis. Output measures were: time to callus first appearance, bridging of involved cortices and time to union, along with the eventual outcome: union/non-union. RESULTS A total of 36 (25 males) eligible patients were identified with a control group of 166 patients (138 males). ANOVA demonstrated class of medication to have a significant effect at two of the three time points and on the eventual outcome. Multiple regression analysis also demonstrated significant impact (p = 0.02). CONCLUSION All classes of medication demonstrated anti-osteogenic effects compared to the control cohort. Biguanides demonstrated this in contrast to the in vitro evidence to date. Sulphonylureas demonstrated this to a greater extent; however, no in vitro evidence is available for comparison within this class. Clinicians should be aware of these delays in bone healing when treating diabetic patients and aim for optimal blood glucose control until such time as further research can be undertaken.
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Affiliation(s)
- C Simpson
- Academic Department of Trauma and Orthopaedics, Leeds General Infirmary, Great George Street, Leeds, England, UK. .,, 35 Potters Lane, East Leake, Loughborough, LE12 6NQ, England, UK.
| | - D Jayaramaraju
- Academic Department of Trauma and Orthopaedics, Ganga Medical Centre and Hospitals, Coimbatore, India
| | - D Agraharam
- Academic Department of Trauma and Orthopaedics, Ganga Medical Centre and Hospitals, Coimbatore, India
| | - S Gudipati
- Academic Department of Trauma and Orthopaedics, Leeds General Infirmary, Great George Street, Leeds, England, UK
| | - R Shanmuganathan
- Academic Department of Trauma and Orthopaedics, Ganga Medical Centre and Hospitals, Coimbatore, India
| | - P V Giannoudis
- Academic Department of Trauma and Orthopaedics, Leeds General Infirmary, Great George Street, Leeds, England, UK.,Leeds Biomedical Research Unit, Chappell Allerton Hospital, Leeds, England, UK
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Palermo A, D'Onofrio L, Eastell R, Schwartz AV, Pozzilli P, Napoli N. Oral anti-diabetic drugs and fracture risk, cut to the bone: safe or dangerous? A narrative review. Osteoporos Int 2015; 26:2073-89. [PMID: 25910746 DOI: 10.1007/s00198-015-3123-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/24/2015] [Indexed: 12/16/2022]
Abstract
Fracture risk is higher in older adults with type 2 diabetes and may be influenced by treatments for diabetes. Oral anti-diabetic drugs have different effects on bone metabolism. The purpose of this review is to describe the effects of these drugs on bone metabolism and fracture risk. Osteoporosis is a progressive skeletal disorder that is characterized by compromised bone strength and increased risk of fracture. This condition has become an important global health problem, affecting approximately 200 million people worldwide. Another chronic and highly prevalent condition is diabetes mellitus, which affects more than 380 million people; both type 1 and type 2 diabetes are risk factors for fracture. Type 2 diabetes, in particular, is associated with impaired bone strength, although it is characterized by normal or elevated bone mineral density. Several therapeutic strategies are available to achieve the best outcomes in the management of diabetes mellitus but these have different effects on bone metabolism. The purpose of this narrative review is to describe the effects of oral hypoglycemic agents (metformin, sulfonylureas, thiazolidinediones, meglitinides, dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists and sodium-dependent glucose transporter 2 inhibitors) on bone metabolism and on the risk of developing fragility fractures in patients with type 2 diabetes. Both diabetes and osteoporosis represent a significant burden in terms of healthcare costs and quality of life. It is very important to choose therapies for diabetes that ensure good metabolic control whilst preserving skeletal health.
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Affiliation(s)
- A Palermo
- Department of Endocrinology and Diabetes, University Campus Bio-Medico of Rome, Via Alvaro del Portillo, 21-00128, Rome, Italy
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Pujari-Palmer M, Pujari-Palmer S, Engqvist H, Karlsson Ott M. Rebamipide delivered by brushite cement enhances osteoblast and macrophage proliferation. PLoS One 2015; 10:e0128324. [PMID: 26023912 PMCID: PMC4449171 DOI: 10.1371/journal.pone.0128324] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/26/2015] [Indexed: 01/04/2023] Open
Abstract
Many of the bioactive agents capable of stimulating osseous regeneration, such as bone morphogenetic protein-2 (BMP-2) or prostaglandin E2 (PGE2), are limited by rapid degradation, a short bioactive half-life at the target site in vivo, or are prohibitively expensive to obtain in large quantities. Rebamipide, an amino acid modified hydroxylquinoline, can alter the expression of key mediators of bone anabolism, cyclo-oxygenase 2 (COX-2), BMP-2 and vascular endothelial growth factor (VEGF), in diverse cell types such as mucosal and endothelial cells or chondrocytes. The present study investigates whether Rebamipide enhances proliferation and differentiation of osteoblasts when delivered from brushite cement. The reactive oxygen species (ROS) quenching ability of Rebampide was tested in macrophages as a measure of bioactivity following drug release incubation times, up to 14 days. Rebamipide release from brushite occurs via non-fickian diffusion, with a rapid linear release of 9.70% ± 0.37% of drug per day for the first 5 days, and an average of 0.5%-1% per day thereafter for 30 days. Rebamipide slows the initial and final cement setting time by up to 3 and 1 minute, respectively, but does not significantly reduce the mechanical strength below 4% (weight percentage). Pre-osteoblast proliferation increases by 24% upon exposure to 0.4 uM Rebamipide, and by up to 73% when Rebamipide is delivered via brushite cement. Low doses of Rebamipide do not adversely affect peak alkaline phosphatase activity in differentiating pre-osteoblasts. Rebamipide weakly stimulates proliferation in macrophages at low concentrations (118 ± 7.4% at 1 uM), and quenches ROS by 40-60%. This is the first investigation of Rebamipide in osteoblasts.
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Affiliation(s)
- Michael Pujari-Palmer
- Division of Applied Material Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
| | - Shiuli Pujari-Palmer
- Division of Applied Material Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
| | - Håkan Engqvist
- Division of Applied Material Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
| | - Marjam Karlsson Ott
- Division of Applied Material Science, Department of Engineering Sciences, Uppsala University, Uppsala, Sweden
- * E-mail:
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Abstract
Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fragility fractures despite increased body weight and normal or higher bone mineral density. The mechanisms by which T2DM increases skeletal fragility are unclear. It is likely that a combination of factors, including a greater risk of falling, regional osteopenia, and impaired bone quality, contributes to the increased fracture risk. Drugs for the treatment of T2DM may also impact on the risk for fractures. For example, thiazolidinediones accelerate bone loss and increase the risk of fractures, particularly in older women. In contrast, metformin and sulfonylureas do not appear to have a negative effect on bone health and may, in fact, protect against fragility fracture. Animal models indicate a potential role for incretin hormones in bone metabolism, but there are only limited data on the impact of dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 agonists on bone health in humans. Animal models also have demonstrated a role for amylin in bone metabolism, but clinical trials in patients with type 1 diabetes with an amylin analog (pramlintide) have not shown a significant impact on bone metabolism. The effects of insulin treatment on fracture risk are inconsistent with some studies showing an increased risk and others showing no effect. Finally, although there is limited information on the latest class of medications for the treatment of T2DM, the sodium-glucose co-transporter-2 inhibitors, these drugs do not seem to increase fracture risk. Because diabetes is an increasingly common chronic condition that can affect patients for many decades, further research into the effects of agents for the treatment of T2DM on bone metabolism is warranted. In this review, the physiological mechanisms and clinical impact of diabetes treatments on bone health and fracture risk in patients with T2DM are described.
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Affiliation(s)
- Matthew P Gilbert
- Division of Endocrinology and Diabetes (M.P.G.), The University of Vermont College of Medicine, Burlington, Vermont 05405; and Florida Hospital Diabetes and Translational Research Institutes and Sanford-Burnham Medical Research Institute, Orlando, Florida 32827
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Pradeep AR, Patnaik K, Nagpal K, Karvekar S, Ramamurthy BL, Naik SB, Suke D, Singh P, Raju A. Efficacy of locally-delivered 1% metformin gel in the treatment of intrabony defects in patients with chronic periodontitis: a randomized, controlled clinical trial. ACTA ACUST UNITED AC 2015; 7:239-45. [DOI: 10.1111/jicd.12150] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 01/14/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Avani R. Pradeep
- Department of Periodontics; Government Dental College and Research Institute; Bangalore Karnataka India
| | - Kaushik Patnaik
- Department of Periodontics; Government Dental College and Research Institute; Bangalore Karnataka India
| | - Kanika Nagpal
- Department of Periodontics; Government Dental College and Research Institute; Bangalore Karnataka India
| | - Shruti Karvekar
- Department of Periodontics; Government Dental College and Research Institute; Bangalore Karnataka India
| | - Bhaskar L. Ramamurthy
- Oxford Dental College and Hospital; Bangalore Karnataka India
- Azamgarh Dental College; Azamgarh Uttar Pradesh India
| | - Savitha B. Naik
- Department of Conservative Dentistry and Endodontics Government Dental College and Research Institute; Bangalore Karnataka India
| | - Deepak Suke
- Department of Periodontics; Government Dental College and Research Institute; Bangalore Karnataka India
| | - Priyanka Singh
- Department of Ophthalmology; Grant Medical College and J.J Group of Hospitals; Mumbai Maharashtra India
| | - Arjun Raju
- Department of Radio-Diagnosis; Uttarakhand Government Medical College; Haldwani Uttarakhand India
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Pradeep AR, Nagpal K, Karvekar S, Patnaik K, Naik SB, Guruprasad CN. Platelet-rich fibrin with 1% metformin for the treatment of intrabony defects in chronic periodontitis: a randomized controlled clinical trial. J Periodontol 2015; 86:729-37. [PMID: 25762357 DOI: 10.1902/jop.2015.140646] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Platelet-rich fibrin (PRF) is a second-generation platelet concentrate that releases various growth factors that promote tissue regeneration. Metformin (MF), a member of the biguanide group, has been shown to facilitate osteoblast differentiation and thus may exhibit a favorable effect on alveolar bone. The current study is designed to evaluate the efficacy of open-flap debridement (OFD) combined with PRF, 1% MF gel, and PRF + 1% MF gel in the treatment of intrabony defects (IBDs) in patients with chronic periodontitis (CP). METHODS One hundred twenty patients with single defects were categorized into four treatment groups: OFD alone, OFD with PRF, OFD with 1% MF, and OFD with PRF plus 1% MF. Clinical parameters such as site-specific plaque index (PI), modified sulcus bleeding index (mSBI), probing depth (PD), relative attachment level (RAL), and gingival marginal level (GML) were recorded at baseline (before surgery) and 9 months postoperatively. Percentage radiographic IBD depth reduction was evaluated using computer-aided software at baseline and 9 months. RESULTS PRF, 1% MF, and PRF + 1% MF groups showed significantly more PD reduction and RAL gain than the OFD-only group. Mean PD reduction and mean RAL gain were found to be greater in the PRF + 1% MF group compared to just PRF or MF at 9 months. Furthermore, PRF + 1% MF group sites showed a significantly greater percentage of radiographic defect depth reduction (52.65% ± 0.031%) compared to MF (48.69% ± 0.026%), PRF (48% ± 0.029%), and OFD alone (9.14% ± 0.04%) at 9 months. CONCLUSION The PRF + 1% MF group showed greater improvements in clinical parameters, with greater percentage radiographic defect depth reduction compared to MF, PRF, or OFD alone in treatment of IBDs in patients with CP.
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Affiliation(s)
- A R Pradeep
- *Department of Periodontics, Government Dental College and Research Institute, Bangalore, Karnataka, India
| | - Kanika Nagpal
- *Department of Periodontics, Government Dental College and Research Institute, Bangalore, Karnataka, India
| | - Shruti Karvekar
- *Department of Periodontics, Government Dental College and Research Institute, Bangalore, Karnataka, India
| | - Kaushik Patnaik
- *Department of Periodontics, Government Dental College and Research Institute, Bangalore, Karnataka, India
| | - Savitha B Naik
- †Department of Conservative Dentistry and Endodontics, Government Dental College and Research Institute
| | - C N Guruprasad
- *Department of Periodontics, Government Dental College and Research Institute, Bangalore, Karnataka, India
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Lastra ML, Molinuevo MS, Giussi JM, Allegretti PE, Blaszczyk-Lezak I, Mijangos C, Cortizo MS. Tautomerizable β-ketonitrile copolymers for bone tissue engineering: Studies of biocompatibility and cytotoxicity. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 51:256-62. [PMID: 25842133 DOI: 10.1016/j.msec.2015.03.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 02/02/2015] [Accepted: 03/09/2015] [Indexed: 01/10/2023]
Abstract
β-Ketonitrile tautomeric copolymers have demonstrated tunable hydrophilicity/hydrophobicity properties according to surrounding environment, and mechanical properties similar to those of human bone tissue. Both characteristic properties make them promising candidates as biomaterials for bone tissue engineering. Based on this knowledge we have designed two scaffolds based on β-ketonitrile tautomeric copolymers which differ in chemical composition and surface morphology. Two of them were nanostructured, using an anodized aluminum oxide (AAO) template, and the other two obtained by solvent casting methodology. They were used to evaluate the effect of the composition and their structural modifications on the biocompatibility, cytotoxicity and degradation properties. Our results showed that the nanostructured scaffolds exhibited higher degradation rate by macrophages than casted scaffolds (6 and 2.5% of degradation for nanostructured and casted scaffolds, respectively), a degradation rate compatible with bone regeneration times. We also demonstrated that the β-ketonitrile tautomeric based scaffolds supported osteoblastic cell proliferation and differentiation without cytotoxic effects, suggesting that these biomaterials could be useful in the bone tissue engineering field.
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Affiliation(s)
- M Laura Lastra
- Laboratorio de Investigaciones en Osteopatías y Metabolismo Mineral (LIOMM), Facultad de Ciencias Exactas, UNLP (1900), 47 y 115, 1900 La Plata, Argentina
| | - M Silvina Molinuevo
- Laboratorio de Investigaciones en Osteopatías y Metabolismo Mineral (LIOMM), Facultad de Ciencias Exactas, UNLP (1900), 47 y 115, 1900 La Plata, Argentina.
| | - Juan M Giussi
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata, CC16 suc. 4, 1900 La Plata, Argentina; Laboratorio de Estudio de Compuestos Orgánicos (LADECOR), Facultad de Ciencias Exactas, UNLP, 47 y 115, 1900 La Plata, Argentina
| | - Patricia E Allegretti
- Laboratorio de Estudio de Compuestos Orgánicos (LADECOR), Facultad de Ciencias Exactas, UNLP, 47 y 115, 1900 La Plata, Argentina
| | - Iwona Blaszczyk-Lezak
- Instituto de Ciencia y Tecnología de Polímeros, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
| | - Carmen Mijangos
- Instituto de Ciencia y Tecnología de Polímeros, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
| | - M Susana Cortizo
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata, CC16 suc. 4, 1900 La Plata, Argentina.
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Hegazy SK. Evaluation of the anti-osteoporotic effects of metformin and sitagliptin in postmenopausal diabetic women. J Bone Miner Metab 2015; 33:207-12. [PMID: 24633493 DOI: 10.1007/s00774-014-0581-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 02/13/2014] [Indexed: 12/21/2022]
Abstract
Osteoporosis is the most important metabolic bone disease in patients with diabetes mellitus. Several studies have documented that metformin is osteogenic in vitro. In contrast, others showed no effect of metformin on the osteogenic differentiation of bone marrow-derived mesenchymal stem cells. Incretin hormones have received much attention because of their beneficial effects beyond glycemia, including on bone health. The study evaluated the anti-osteoporotic effect of metformin and sitagliptin in postmenopausal diabetic women. Forty postmenopausal diabetic women were randomly divided into two equal groups. Group 1 received metformin (Glucophage(®) 500 mg) 1 tablet twice daily, and group 2 received sitagliptin (Januvia(®) 100 mg) 1 tablet/day, for 12 weeks. Fasting blood and urine samples were collected for measurement of serum total alkaline phosphatase (ALP), osteocalcin, and urinary deoxypyridinoline (DPD). Laboratory tests were measured at baseline, after 4 and 8 weeks, and at the end of the study. Bone mineral density of the anterior posterior lumbar spine was measured by dual energy X-ray absorptiometry at baseline and after 12 weeks of the intervention. In the metformin-treated group, the mean values for all markers of bone turnover at 12 weeks of treatment were not significantly different from baseline. In group 2, the mean serum total ALP was significantly decreased, serum osteocalcin levels were non-significantly decreased gradually by 10% at 12 weeks, while urinary DPD decreased significantly and was then maintained at 28% decrease at 12 weeks. In conclusion, metformin is neither osteogenic nor has anti-osteoporotic effect, while sitagliptin could positively regulate bone metabolism.
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Abstract
There are several mechanisms by which diabetes could affect bone mass and strength. These mechanisms include insulin deficiency; hyperglycemia; the accumulation of advanced glycation end products that may influence collagen characteristics; marrow adiposity and bone inflammation. Furthermore, associated diabetic complications and treatment with thaizolidinediones may also increase risk of fracturing. The following article provides its readers with an update on the latest information pertaining to diabetes related bone skeletal fragility. In the authors' opinion, future studies are needed in order to clarify the impact of different aspects of diabetes metabolism, glycemic control, and specific treatments for diabetes on bone. Given that dual energy x-ray absorptiometry is a poor predictor of bone morbidity in this group of patients, there is a need to explore novel approaches for assessing bone quality. It is important that we develop a better understanding of how diabetes affects bone in order to improve our ability to protect bone health and prevent fractures in the growing population of adults with diabetes.
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Affiliation(s)
- Naiemh Abdalrahman
- a Developmental Endocrinology Research Group, Royal Hospital for Sick Children, School of Medicine, University of Glasgow, Yorkhill, Glasgow G3 8SJ, UK
| | - Suet Ching Chen
- a Developmental Endocrinology Research Group, Royal Hospital for Sick Children, School of Medicine, University of Glasgow, Yorkhill, Glasgow G3 8SJ, UK
| | - Jessie Ruijun Wang
- a Developmental Endocrinology Research Group, Royal Hospital for Sick Children, School of Medicine, University of Glasgow, Yorkhill, Glasgow G3 8SJ, UK
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Dede AD, Tournis S, Dontas I, Trovas G. Type 2 diabetes mellitus and fracture risk. Metabolism 2014; 63:1480-90. [PMID: 25284729 DOI: 10.1016/j.metabol.2014.09.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 08/27/2014] [Accepted: 09/19/2014] [Indexed: 02/06/2023]
Abstract
Increased fracture risk, traditionally associated with type 1 diabetes, has lately been of great concern in patients with type 2 diabetes. A variable increase in fracture risk has been reported, ranging from 20% to 3-fold, depending on skeletal site, diabetes duration and study design. Longer disease duration, the presence of diabetic complications, inadequate glycemic control, insulin use and increased risk for falls are all reported to increase fracture risk. Patients with type 2 diabetes display a unique skeletal phenotype with either normal or more frequently increased, bone mineral density and impaired structural and geometric properties. Recently, alterations in bone material properties seem to be the predominant defect leading to increased bone fragility. Accumulation of advanced glycation end-products and changes in collagen cross-linking along with suppression of bone turnover seem to be significant factors impairing bone strength. FRAX score has been reported to underestimate fracture risk and lumbar spine BMD is inadequate in predicting vertebral fractures. Anti-diabetic medications, apart from thiazolidinediones, appear to be safe for the skeleton, although more data are needed. Optimal strategies to reduce skeletal fragility in type 2 diabetic patients are yet to be determined.
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Affiliation(s)
- Anastasia D Dede
- Department of Endocrinology and Metabolism, Hippokrateion General Hospital, Vas. Sofias 114, 11527 Athens, Greece.
| | - Symeon Tournis
- Laboratory for Research of Musculoskeletal System "Theodoros Garofalidis", University of Athens, KAT Hospital, Athens, Greece
| | - Ismene Dontas
- Laboratory for Research of Musculoskeletal System "Theodoros Garofalidis", University of Athens, KAT Hospital, Athens, Greece
| | - George Trovas
- Laboratory for Research of Musculoskeletal System "Theodoros Garofalidis", University of Athens, KAT Hospital, Athens, Greece
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de Waard EAC, van Geel TACM, Savelberg HHCM, Koster A, Geusens PPMM, van den Bergh JPW. Increased fracture risk in patients with type 2 diabetes mellitus: an overview of the underlying mechanisms and the usefulness of imaging modalities and fracture risk assessment tools. Maturitas 2014; 79:265-74. [PMID: 25192916 DOI: 10.1016/j.maturitas.2014.08.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 08/06/2014] [Indexed: 12/11/2022]
Abstract
Type 2 diabetes mellitus has recently been linked to an increased fracture risk. Since bone mass seems to be normal to elevated in patient with type 2 diabetes, the increased fracture risk is thought to be due to both an increased falling frequency and decreased bone quality. The increased falling frequency is mainly a result of complications of the disease such as a retinopathy and polyneuropathy. Bone quality is affected through changes in bone shape, bone micro-architecture, and in material properties such as bone mineralization and the quality of collagen. Commonly used methods for predicting fracture risk such as dual energy X-ray absorptiometry and fracture risk assessment tools are helpful in patients with type 2 diabetes mellitus, but underestimate the absolute fracture risk for a given score. New imaging modalities such as high resolution peripheral quantitative computed tomography are promising for giving insight in the complex etiology underlying the fragility of the diabetic bone, as they can give more insight into the microarchitecture and geometry of the bone. We present an overview of the contributing mechanisms to the increased fracture risk and the usefulness of imaging modalities and risk assessment tools in predicting fracture risk in patients with type 2 diabetes.
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Affiliation(s)
- Ellis A C de Waard
- Maastricht University Medical Centre/NUTRIM, Department of Internal Medicine, Subdivision of Rheumatology, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
| | - Tineke A C M van Geel
- Maastricht University/CAPHRI and NUTRIM, Department of Family Medicine, P.O. Box 616, 6200MD Maastricht, The Netherlands
| | - Hans H C M Savelberg
- Maastricht University Medical Centre/NUTRIM, Department of Human Movement Science, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
| | - Annemarie Koster
- Maastricht University/CAPHRI, Department of Social Medicine, School for Public Health and Primary Care, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
| | - Piet P M M Geusens
- Maastricht University Medical Centre/CAPHRI, Department of Internal Medicine, Subdivision of Rheumatology, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands; University of Hasselt, Biomedical Research Institute, P.O. Box 6, 3590 Diepenbeek, Belgium
| | - Joop P W van den Bergh
- Maastricht University Medical Centre/NUTRIM, Department of Internal Medicine, Subdivision of Rheumatology, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands; University of Hasselt, Biomedical Research Institute, P.O. Box 6, 3590 Diepenbeek, Belgium; VieCuri Medical Centre, Department of Internal Medicine, Subdivision of Endocrinology, P.O. Box 1926, 5900 BX Venlo, The Netherlands
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FFAs-ROS-ERK/P38 pathway plays a key role in adipocyte lipotoxicity on osteoblasts in co-culture. Biochimie 2014; 101:123-31. [DOI: 10.1016/j.biochi.2014.01.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 01/03/2014] [Indexed: 01/31/2023]
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Farr JN, Drake MT, Amin S, Melton LJ, McCready LK, Khosla S. In vivo assessment of bone quality in postmenopausal women with type 2 diabetes. J Bone Miner Res 2014; 29:787-95. [PMID: 24123088 PMCID: PMC3961509 DOI: 10.1002/jbmr.2106] [Citation(s) in RCA: 361] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 09/14/2013] [Accepted: 09/26/2013] [Indexed: 01/13/2023]
Abstract
Although patients with type 2 diabetes (T2D) are at significant risk for well-recognized diabetic complications, including macrovascular disease, retinopathy, nephropathy, and neuropathy, it is also clear that T2D patients are at increased risk for fragility fractures. Furthermore, fragility fractures in patients with T2D occur at higher bone mineral density (BMD) values compared to nondiabetic controls, suggesting abnormalities in bone material strength (BMS) and/or bone microarchitecture (bone "quality"). Thus, we performed in vivo microindentation testing of the tibia to directly measure BMS in 60 postmenopausal women (age range, 50-80 years) including 30 patients diagnosed with T2D for >10 years and 30 age-matched, nondiabetic controls. Regional BMD was measured by dual-energy X-ray absorptiometry (DXA); cortical and trabecular bone microarchitecture was assessed from high-resolution peripheral quantitative computed tomography (HRpQCT) images of the distal radius and tibia. Compared to controls, T2D patients had significantly lower BMS: unadjusted (-11.7%; p<0.001); following adjustment for body mass index (BMI) (-10.5%; p<0.001); and following additional adjustment for age, hypertension, nephropathy, neuropathy, retinopathy, and vascular disease (-9.2%; p=0.022). By contrast, after adjustment for confounding by BMI, T2D patients had bone microarchitecture and BMD that were not significantly different than controls; however, radial cortical porosity tended to be higher in the T2D patients. In addition, patients with T2D had significantly reduced serum markers of bone turnover (all p<0.001) compared to controls. Of note, in patients with T2D, the average glycated hemoglobin level over the previous 10 years was negatively correlated with BMS (r=-0.41; p=0.026). In conclusion, these findings represent the first demonstration of compromised BMS in patients with T2D. Furthermore, our results confirm previous studies demonstrating low bone turnover in patients with T2D and highlight the potential detrimental effects of prolonged hyperglycemia on bone quality. Thus, the skeleton needs to be recognized as another important target tissue subject to diabetic complications. © 2014 American Society for Bone and Mineral Research.
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Affiliation(s)
- Joshua N Farr
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
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McCarty MF. AMPK activation--protean potential for boosting healthspan. AGE (DORDRECHT, NETHERLANDS) 2014; 36:641-663. [PMID: 24248330 PMCID: PMC4039279 DOI: 10.1007/s11357-013-9595-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 10/22/2013] [Indexed: 06/01/2023]
Abstract
AMP-activated kinase (AMPK) is activated when the cellular (AMP+ADP)/ATP ratio rises; it therefore serves as a detector of cellular "fuel deficiency." AMPK activation is suspected to mediate some of the health-protective effects of long-term calorie restriction. Several drugs and nutraceuticals which slightly and safely impede the efficiency of mitochondrial ATP generation-most notably metformin and berberine-can be employed as clinical AMPK activators and, hence, may have potential as calorie restriction mimetics for extending healthspan. Indeed, current evidence indicates that AMPK activators may reduce risk for atherosclerosis, heart attack, and stroke; help to prevent ventricular hypertrophy and manage congestive failure; ameliorate metabolic syndrome, reduce risk for type 2 diabetes, and aid glycemic control in diabetics; reduce risk for weight gain; decrease risk for a number of common cancers while improving prognosis in cancer therapy; decrease risk for dementia and possibly other neurodegenerative disorders; help to preserve the proper structure of bone and cartilage; and possibly aid in the prevention and control of autoimmunity. While metformin and berberine appear to have the greatest utility as clinical AMPK activators-as reflected by their efficacy in diabetes management-regular ingestion of vinegar, as well as moderate alcohol consumption, may also achieve a modest degree of health-protective AMPK activation. The activation of AMPK achievable with any of these measures may be potentiated by clinical doses of the drug salicylate, which can bind to AMPK and activate it allosterically.
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Affiliation(s)
- Mark F McCarty
- Catalytic Longevity, 7831 Rush Rose Dr., Apt. 316, Carlsbad, CA, 92009, USA,
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Salai M, Somjen D, Gigi R, Yakobson O, Katzburg S, Dolkart O. Effects of commonly used medications on bone tissue mineralisation in SaOS-2 human bone cell line: an in vitro study. Bone Joint J 2013; 95-B:1575-80. [PMID: 24151282 DOI: 10.1302/0301-620x.95b11.31158] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We analysed the effects of commonly used medications on human osteoblastic cell activity in vitro, specifically proliferation and tissue mineralisation. A list of medications was retrieved from the records of patients aged > 65 years filed in the database of the largest health maintenance organisation in our country (> two million members). Proliferation and mineralisation assays were performed on the following drugs: rosuvastatin (statin), metformin (antidiabetic), metoprolol (β-blocker), citalopram (selective serotonin reuptake inhibitor [SSRI]), and omeprazole (proton pump inhibitor (PPI)). All tested drugs significantly stimulated DNA synthesis to varying degrees, with rosuvastatin 5 µg/ml being the most effective among them (mean 225% (SD 20)), compared with metformin 10 µg/ml (185% (SD 10)), metoprolol 0.25 µg/ml (190% (SD 20)), citalopram 0.05 µg/ml (150% (sd 10)) and omeprazole 0.001 µg/ml (145% (SD 5)). Metformin and metoprolol (to a small extent) and rosuvastatin (to a much higher extent) inhibited cell mineralisation (85% (SD 5)). Our results indicate the need to evaluate the medications prescribed to patients in terms of their potential action on osteoblasts. Appropriate evaluation and prophylactic treatment (when necessary) might lower the incidence and costs associated with potential medication-induced osteoporosis.
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Affiliation(s)
- M Salai
- Tel-Aviv Sourasky Medical Center, Division of Orthopedic Surgery, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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130
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Zhou R, Wang Z, Ma C. Hispidulin Exerts Anti-osteoporotic Activity in Ovariectomized Mice via Activating AMPK Signaling Pathway. Cell Biochem Biophys 2013; 69:311-7. [DOI: 10.1007/s12013-013-9800-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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131
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Agarwal A. Osteogenic action of anti-diabetic drug metformin in periodontal disease. J Pharm Bioallied Sci 2013; 5:327. [PMID: 24302843 PMCID: PMC3831748 DOI: 10.4103/0975-7406.120070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Ashish Agarwal
- Department of Periodontology, Institute of Dental Sciences, Bareilly, Uttar Pradesh, India E-mail:
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132
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Jeyabalan J, Viollet B, Smitham P, Ellis SA, Zaman G, Bardin C, Goodship A, Roux JP, Pierre M, Chenu C. The anti-diabetic drug metformin does not affect bone mass in vivo or fracture healing. Osteoporos Int 2013; 24:2659-70. [PMID: 23644877 PMCID: PMC3777188 DOI: 10.1007/s00198-013-2371-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 04/08/2013] [Indexed: 02/15/2023]
Abstract
SUMMARY The present study shows no adverse effects of the anti-diabetic drug metformin on bone mass and fracture healing in rodents but demonstrates that metformin is not osteogenic in vivo, as previously proposed. INTRODUCTION In view of the increased incidence of fractures in patients with type 2 diabetes mellitus (T2DM), we investigated the effects of metformin, a widely used T2DM therapy, on bone mass and fracture healing in vivo using two different rodent models and modes of metformin administration. METHODS We first subjected 12-week-old female C57BL/6 mice to ovariectomy (OVX). Four weeks after OVX, mice received either saline or metformin administered by gavage (100 mg/kg/daily). After 4 weeks of treatment, bone micro-architecture and cellular activity were determined in tibia by micro-CT and bone histomorphometry. In another experiment, female Wistar rats aged 3 months were given only water or metformin for 8 weeks via the drinking water (2 mg/ml). After 4 weeks of treatment, a mid-diaphyseal osteotomy was performed in the left femur. Rats were sacrificed 4 weeks after osteotomy and bone architecture analysed by micro-CT in the right tibia while fracture healing and callus volume were determined in the left femur by X-ray analysis and micro-CT, respectively. RESULTS In both models, our results show no significant differences in cortical and trabecular bone architecture in metformin-treated rodents compared to saline. Metformin had no effect on bone resorption but reduced bone formation rate in trabecular bone. Mean X-ray scores assessed on control and metformin fractures showed no significant differences of healing between the groups. Fracture callus volume and mineral content after 4 weeks were similar in both groups. CONCLUSIONS Our results indicate that metformin has no effect on bone mass in vivo or fracture healing in rodents.
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Affiliation(s)
- J. Jeyabalan
- Department of Comparative and Biomedical Sciences, Royal Veterinary College, Royal College Street, London, NW1 0TU UK
| | - B. Viollet
- INSERM U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - P. Smitham
- Institute of Orthopaedics & Musculoskeletal Science, UCL, Royal National Orthopaedic Hospital, Stanmore, UK
| | - S. A. Ellis
- Department of Comparative and Biomedical Sciences, Royal Veterinary College, Royal College Street, London, NW1 0TU UK
| | - G. Zaman
- Department of Comparative and Biomedical Sciences, Royal Veterinary College, Royal College Street, London, NW1 0TU UK
| | - C. Bardin
- UF Pharmacocinétique et Pharmacochimie, CHU Cochin AP–HP, Paris, France
| | - A. Goodship
- Institute of Orthopaedics & Musculoskeletal Science, UCL, Royal National Orthopaedic Hospital, Stanmore, UK
| | - J. P. Roux
- INSERM UMR1033, Université de Lyon, Lyon, France
| | - M. Pierre
- INSERM UMR1033, Université de Lyon, Lyon, France
| | - C. Chenu
- Department of Comparative and Biomedical Sciences, Royal Veterinary College, Royal College Street, London, NW1 0TU UK
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133
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Cao X, Li H, Tao H, Wu N, Yu L, Zhang D, Lu X, Zhu J, Lu Z, Zhu Q. Metformin inhibits vascular calcification in female rat aortic smooth muscle cells via the AMPK-eNOS-NO pathway. Endocrinology 2013; 154:3680-9. [PMID: 24025223 DOI: 10.1210/en.2013-1002] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Metformin exhibits diverse protective effects against diabetic complications, such as bone loss. Here, we investigated the effect of metformin on vascular calcification, another type 2 diabetes complication. In female rat aortic smooth muscle cells (RASMCs), we observed that metformin significantly alleviated β-glycerophosphate-induced Ca deposition and alkaline phosphatase activity, corresponding with reduced expression of some specific genes in osteoblast-like cells, including Runx2 and bone morphogenetic protein-2, and positive effects on α-actin expression, a specific marker of smooth muscle cells. Mechanistic analysis showed that phosphorylation levels of both AMP-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS) were increased with NO overproduction. After inhibition of either AMPK or eNOS with the pharmacologic inhibitors, compound C or Nω-Nitro-L-arginine methyl ester, NO production was lowered and metformin-meditated vascular protection against β-glycerophosphate-induced Ca deposition was removed. Our results support that metformin prevents vascular calcification via AMPK-eNOS-NO pathway.
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MESH Headings
- AMP-Activated Protein Kinases/antagonists & inhibitors
- AMP-Activated Protein Kinases/chemistry
- AMP-Activated Protein Kinases/metabolism
- Animals
- Aorta/cytology
- Aorta/drug effects
- Aorta/metabolism
- Aorta/pathology
- Cell Transdifferentiation/drug effects
- Cells, Cultured
- Diabetic Angiopathies/chemically induced
- Diabetic Angiopathies/metabolism
- Diabetic Angiopathies/pathology
- Diabetic Angiopathies/prevention & control
- Enzyme Activation/drug effects
- Enzyme Inhibitors/adverse effects
- Female
- Glycerophosphates/adverse effects
- Glycerophosphates/antagonists & inhibitors
- Hypoglycemic Agents/antagonists & inhibitors
- Hypoglycemic Agents/pharmacology
- Metformin/antagonists & inhibitors
- Metformin/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Nitric Oxide/metabolism
- Nitric Oxide Synthase Type III/antagonists & inhibitors
- Nitric Oxide Synthase Type III/chemistry
- Nitric Oxide Synthase Type III/metabolism
- Phosphorylation/drug effects
- Protein Kinase Inhibitors/adverse effects
- Protein Processing, Post-Translational/drug effects
- Rats
- Rats, Sprague-Dawley
- Signal Transduction/drug effects
- Vascular Calcification/chemically induced
- Vascular Calcification/metabolism
- Vascular Calcification/pathology
- Vascular Calcification/prevention & control
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Affiliation(s)
- Xiaorui Cao
- PhD, State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, 710032 Xi'an, China, ; or Qingshen Zhu, MD, PhD, Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, 710032 Xi'an, China, E-mail:
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134
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Montagnani A, Gonnelli S. Antidiabetic therapy effects on bone metabolism and fracture risk. Diabetes Obes Metab 2013; 15:784-91. [PMID: 23368527 DOI: 10.1111/dom.12077] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 09/25/2012] [Accepted: 01/21/2013] [Indexed: 12/22/2022]
Abstract
Patients with diabetes are at greater risk of fractures mostly due to not only to extraskeletal factors, such as propensity to fall, but also to bone quality alteration, which reduces bone strength. In people with diabetes, insulin deficiency and hyperglycaemia seem to play a role in determining bone formation alteration by advanced glycation end product (AGE) accumulation or AGE/RAGE (receptors for AGE) axis imbalance, which directly influence osteoblast activity. Moreover, hyperglycaemia and oxidative stress are able to negatively influence osteocalcin production and the Wnt signalling pathways with an imbalance of osteoblast/osteoclast activity leading to bone quality reduction as global effect. In addition, other factors such as insulin growth factors and peroxisome proliferator-activated receptor-γ pathways seem to have an important role in the pathophysiology of osteoporosis in diabetes. Although there are conflicting data in literature, adequate glycaemic control with hypoglycaemic treatment may be an important element in preventing bone tissue alterations in both type 1 and type 2 diabetes. Attention should be paid to the use of thiazolidinediones, especially in older women, because the direct negative effect on bone could exceed the positive effect of glycaemic control. Finally, preliminary data on animals and in humans suggest the hypothesis that incretins and dipeptidyl peptidase-4 inhibitors could have a positive effect on bone metabolism by a direct effect on bone cells; however, such issue needs further investigations.
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Affiliation(s)
- A Montagnani
- Metabolic Bone Diseases and Osteoporosis Ambulatory, Internal Medicine Unit, Misericordia Hospital, Grosseto, Italy.
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135
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Rao NS, Pradeep A, Kumari M, Naik SB. Locally Delivered 1% Metformin Gel in the Treatment of Smokers with Chronic Periodontitis: A Randomized Controlled Clinical Trial. J Periodontol 2013; 84:1165-71. [DOI: 10.1902/jop.2012.120298] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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136
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Tolosa MJ, Chuguransky SR, Sedlinsky C, Schurman L, McCarthy AD, Molinuevo MS, Cortizo AM. Insulin-deficient diabetes-induced bone microarchitecture alterations are associated with a decrease in the osteogenic potential of bone marrow progenitor cells: preventive effects of metformin. Diabetes Res Clin Pract 2013; 101:177-86. [PMID: 23806481 DOI: 10.1016/j.diabres.2013.05.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/21/2013] [Accepted: 05/30/2013] [Indexed: 12/15/2022]
Abstract
AIMS Diabetes mellitus is associated with metabolic bone disease and increased low-impact fractures. The insulin-sensitizer metformin possesses in vitro, in vivo and ex vivo osteogenic effects, although this has not been adequately studied in the context of diabetes. We evaluated the effect of insulin-deficient diabetes and/or metformin on bone microarchitecture, on osteogenic potential of bone marrow progenitor cells (BMPC) and possible mechanisms involved. METHODS Partially insulin-deficient diabetes was induced in rats by nicotinamide/streptozotocin-injection, with or without oral metformin treatment. Femoral metaphysis micro-architecture, ex vivo osteogenic potential of BMPC, and BMPC expression of Runx-2, PPARγ and receptor for advanced glycation endproducts (RAGE) were investigated. RESULTS Histomorphometric analysis of diabetic femoral metaphysis demonstrated a slight decrease in trabecular area and a significant reduction in osteocyte density, growth plate height and TRAP (tartrate-resistant acid phosphatase) activity in the primary spongiosa. BMPC obtained from diabetic animals showed a reduction in Runx-2/PPARγ ratio and in their osteogenic potential, and an increase in RAGE expression. Metformin treatment prevented the diabetes-induced alterations in bone micro-architecture and BMPC osteogenic potential. CONCLUSION Partially insulin-deficient diabetes induces deleterious effects on long-bone micro-architecture that are associated with a decrease in BMPC osteogenic potential, which could be mediated by a decrease in their Runx-2/PPARγ ratio and up-regulation of RAGE. These diabetes-induced alterations can be totally or partially prevented by oral administration of metformin.
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Affiliation(s)
- María José Tolosa
- Laboratorio de Investigación en Osteopatías y Metabolismo Mineral, Department of Biological Sciences, School of Exact Sciences, National University of La Plata, Argentina
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137
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Bilezikian JP, Josse RG, Eastell R, Lewiecki EM, Miller CG, Wooddell M, Northcutt AR, Kravitz BG, Paul G, Cobitz AR, Nino AJ, Fitzpatrick LA. Rosiglitazone decreases bone mineral density and increases bone turnover in postmenopausal women with type 2 diabetes mellitus. J Clin Endocrinol Metab 2013; 98:1519-28. [PMID: 23450056 DOI: 10.1210/jc.2012-4018] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
CONTEXT Postmenopausal status and type 2 diabetes mellitus (T2DM) are independent risk factors for fractures. An increased fracture risk has been observed with rosiglitazone (RSG), a thiazolidinedione, in patients with T2DM. DESIGN AND SETTING This was a randomized, double-blind study in postmenopausal women with T2DM. A 52-week double-blind phase (RSG or metformin [MET]) was followed by a 24-week open-label phase, during which time all patients received MET. MAIN OUTCOME MEASURES The primary endpoint was to assess the mean percentage change in bone mineral density (BMD) at the femoral neck (FN) by dual-energy x-ray absorptiometry from baseline to week 52 in the RSG treatment group. Key secondary objectives included assessment of changes in BMD at the total hip, trochanter, and lumbar spine and to evaluate RSG effects on bone turnover markers. RESULTS From baseline to week 52, RSG was associated with a reduction in FN BMD by dual-energy x-ray absorptiometry (-1.47%). During the open-label phase (weeks 52-76), no further loss in FN BMD was observed. A decrease in BMD occurred at the total hip during RSG or MET treatment at 52 weeks (-1.62 and -0.72%, respectively). Total hip BMD loss by RSG was attenuated after switching to MET and was similar between treatment groups at the end of the open-label phase. From baseline to week 52, bone turnover markers significantly increased with RSG compared with MET, but decreased significantly during the open-label phase. CONCLUSIONS RSG for 52 weeks in postmenopausal women with T2DM was associated with small reductions in FN, total hip, and lumbar spine BMD and increased bone turnover markers. These effects are attenuated after cessation of RSG treatment.
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Affiliation(s)
- John P Bilezikian
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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138
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Ko JC, Huang YC, Chen HJ, Tseng SC, Chiu HC, Wo TY, Huang YJ, Weng SH, Chiou RYY, Lin YW. Metformin induces cytotoxicity by down-regulating thymidine phosphorylase and excision repair cross-complementation 1 expression in non-small cell lung cancer cells. Basic Clin Pharmacol Toxicol 2013; 113:56-65. [PMID: 23362830 DOI: 10.1111/bcpt.12052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 01/02/2013] [Indexed: 01/22/2023]
Abstract
Metformin is an antidiabetic drug recently shown to inhibit cancer cell proliferation and growth, although the involved molecular mechanisms have not been elucidated. In many cancer cells, high expression of thymidine phosphorylase (TP) and Excision repair cross-complementation 1 (ERCC1) is associated with poor prognosis. We used A549 and H1975 human non-small cell lung cancer (NSCLC) cell lines to investigate the role of TP and ERCC1 expression in metformin-induced cytotoxicity. Metformin treatment decreased cellular TP and ERCC1 protein and mRNA levels by down-regulating phosphorylated MEK1/2-ERK1/2 protein levels in a dose- and time-dependent manner. The enforced expression of the constitutively active MEK1 (MEK1-CA) vectors significantly restored cellular TP and ERCC1 protein levels and cell viability. Specific inhibition of TP and ERCC1 expression by siRNA enhanced the metformin-induced cytotoxicity and growth inhibition. Arachidin-1, an antioxidant stilbenoid, further decreased TP and ERCC1 expression and augmented metformin's cytotoxic effect, which was abrogated in lung cancer cells transfected with MEK1/2-CA expression vector. In conclusion, metformin induces cytotoxicity by down-regulating TP and ERCC1 expression in NSCLC cells.
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Affiliation(s)
- Jen-Chung Ko
- Department of Internal Medicine, National Taiwan University Hospital, Hsin-Chu Branch, Taiwan
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139
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Pradeep A, Rao NS, Naik SB, Kumari M. Efficacy of Varying Concentrations of Subgingivally Delivered Metformin in the Treatment of Chronic Periodontitis: A Randomized Controlled Clinical Trial. J Periodontol 2013; 84:212-20. [DOI: 10.1902/jop.2012.120025] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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140
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AICAR, a small chemical molecule, primes osteogenic differentiation of adult mesenchymal stem cells. Int J Artif Organs 2012; 34:1128-36. [PMID: 22198598 DOI: 10.5301/ijao.5000007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2011] [Indexed: 12/14/2022]
Abstract
The chemical approach to controlling stem cell fates is emerging as a powerful tool, holding great promise in tissue engineering and regenerative medicine. Various small molecules have been demonstrated capable of modulating stem cell differentiation. In this paper, we studied the effects of 5-aminoimidazole-4-carboxamide-1-ß-riboside (AICAR), an activator of AMP-activated protein kinase (AMPK), on mesenchymal stem cells (MSCs). AICAR at high concentrations (1.0-2.0 mM) significantly inhibited proliferation of both human amnion-derived MSCs (hAMSCs) and rabbit bone marrow-derived MSCs (BM-MSCs). Most importantly, AICAR efficiently promoted the osteogenic differentiation of hAMSCs and BM-MSCs in both growth medium and osteogenic medium. However, Metformin, another AMPK activator, showed no such effects. Meanwhile, AICAR significantly inhibited adipogenic differentiation of hAMSCs and BM-MSCs. Our data suggests that AICAR represents a potent molecule, which can be applied in bone tissue regeneration.
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141
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Protective effect of metformin on periapical lesions in rats by decreasing the ratio of receptor activator of nuclear factor kappa B ligand/osteoprotegerin. J Endod 2012; 38:943-7. [PMID: 22703658 DOI: 10.1016/j.joen.2012.03.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 03/02/2012] [Accepted: 03/11/2012] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Metformin, one of the antihyperglycemic agents commonly used for the treatment of type 2 diabetes, was shown to inhibit osteoclast formation. The current study aimed to investigate the effects of systemically administered metformin on alveolar bone resorption and on the ratio of receptor activator of nuclear factor kappa B ligand/osteoprotegerin (RANKL/OPG) in rats subjected to experimental periapical lesions. METHODS Forty adult male Wistar rats were divided equally into control and experimental groups, and the pulp chambers of their mandibular first molars were exposed to the oral environment to induce periapical lesions. The experimental group received daily intramuscular injections of metformin at 40 mg/kg doses, whereas the control group received only the saline vehicle. The injections were initiated 1 day before the periapical lesion induction and then were continued daily throughout the entire experimental period. Two or 4 weeks after pulp exposure, the rats were killed, and the mandibles were prepared for histologic analysis, enzyme histochemistry, immunohistochemistry, and immunofluorescence. RESULTS The number of RANKL-positive and tartrate-resistant acid phosphatase (TRAP)-positive cells in the metformin-treated groups decreased on day 14, whereas the number of OPG-positive cells increased on day 28. The periapical bone loss area in the metformin-treated group significantly decreased on day 28 compared with the control group. CONCLUSIONS Metformin inhibits the periapical lesions possibly by lowering the RANKL/OPG ratio, subsequently reducing the number of osteoclasts and bone resorption areas.
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142
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Mai QG, Zhang ZM, Xu S, Lu M, Zhou RP, Zhao L, Jia CH, Wen ZH, Jin DD, Bai XC. Metformin stimulates osteoprotegerin and reduces RANKL expression in osteoblasts and ovariectomized rats. J Cell Biochem 2012; 112:2902-9. [PMID: 21618594 DOI: 10.1002/jcb.23206] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Anti-diabetic drug metformin has been shown to enhance osteoblasts differentiation and inhibit osteoclast differentiation in vitro and prevent bone loss in ovariectomized (OVX) rats. But the mechanisms through which metformin regulates osteoclastogensis are not known. Osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) are cytokines predominantly secreted by osteoblasts and play critical roles in the differentiation and function of osteoclasts. In this study, we demonstrated that metformin dose-dependently stimulated OPG and reduced RANKL mRNA and protein expression in mouse calvarial osteoblasts and osteoblastic cell line MC3T3-E1. Inhibition of AMP-activated protein kinase (AMPK) and CaM kinase kinase (CaMKK), two targets of metformin, suppressed endogenous and metformin-induced OPG secretion in osteoblasts. Moreover, supernatant of osteoblasts treated with metformin reduced formation of tartrate resistant acid phosphatase (TRAP)-positive multi-nucleated cells in Raw264.7 cells. Most importantly, metformin significantly increased total body bone mineral density, prevented bone loss and decreased TRAP-positive cells in OVX rats proximal tibiae, accompanied with an increase of OPG and decrease of RANKL expression. These in vivo and in vitro studies suggest that metformin reduces RANKL and stimulates OPG expression in osteoblasts, further inhibits osteoclast differentiation and prevents bone loss in OVX rats.
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Affiliation(s)
- Qi-Guang Mai
- Department of Orthopedic, The Third Affiliated Hospital of Southern Medical University, Guangzhou 510665, China
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143
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Sun DC, Li DH, Ji HC, Rao GZ, Liang LH, Ma AJ, Xie C, Zou GK, Song YL. In vitro culture and characterization of alveolar bone osteoblasts isolated from type 2 diabetics. Braz J Med Biol Res 2012; 45:502-9. [PMID: 22473318 PMCID: PMC3854304 DOI: 10.1590/s0100-879x2012007500054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 03/23/2012] [Indexed: 11/22/2022] Open
Abstract
In order to understand the mechanisms of poor osseointegration following dental implants in type 2 diabetics, it is important to study the biological properties of alveolar bone osteoblasts isolated from these patients. We collected alveolar bone chips under aseptic conditions and cultured them in vitro using the tissue explants adherent method. The biological properties of these cells were characterized using the following methods: alkaline phosphatase (ALP) chemical staining for cell viability, Alizarin red staining for osteogenic characteristics, MTT test for cell proliferation, enzyme dynamics for ALP contents, radio-immunoassay for bone gla protein (BGP) concentration, and ELISA for the concentration of type I collagen (COL-I) in the supernatant. Furthermore, we detected the adhesion ability of two types of cells from titanium slices using non-specific immunofluorescence staining and cell count. The two cell forms showed no significant difference in morphology under the same culture conditions. However, the alveolar bone osteoblasts received from type 2 diabetic patients had slower growth, lower cell activity and calcium nodule formation than the normal ones. The concentration of ALP, BGP and COL-I was lower in the supernatant of alveolar bone osteoblasts received from type 2 diabetic patients than in that received from normal subjects (P < 0.05). The alveolar bone osteoblasts obtained from type 2 diabetic patients can be successfully cultured in vitro with the same morphology and biological characteristics as those from normal patients, but with slower growth and lower concentration of specific secretion and lower combining ability with titanium than normal ones.
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Affiliation(s)
- Dao-Cai Sun
- Department of Implant Dentistry, School of Stomatology, Fourth Military Medical University, Xi'an, China
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144
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Abstract
There is increasing evidence that osteoporosis, similarly to obesity and diabetes, could be another disorder of energy metabolism. AMP-activated protein kinase (AMPK) has emerged over the last decade as a key sensing mechanism in the regulation of cellular energy homeostasis and is an essential mediator of the central and peripheral effects of many hormones on the metabolism of appetite, fat and glucose. Novel work demonstrates that the AMPK signaling pathway also plays a role in bone physiology. Activation of AMPK promotes bone formation in vitro and the deletion of α or β subunit of AMPK decreases bone mass in mice. Furthermore, AMPK activity in bone cells is regulated by the same hormones that regulate food intake and energy expenditure through AMPK activation in the brain and peripheral tissues. AMPK is also activated by antidiabetic drugs such as metformin and thiazolidinediones (TZDs), which also impact on skeletal metabolism. Interestingly, TZDs have detrimental skeletal side effects, causing bone loss and increasing the risk of fractures, although the role of AMPK mediation is still unclear. These data are presented in this review that also discusses the potential roles of AMPK in bone as well as the possibility for AMPK to be a future therapeutic target for intervention in osteoporosis.
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Affiliation(s)
- J Jeyabalan
- Royal Veterinary College, Royal College Street, London NW1 0TU, UK
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145
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Serezhenkov VA, Kuznetsov IS, Romantsova TI, Kuznetsova MI, Vanin AF. Antidiabetes drug metformin is a donor of nitric oxide: EPR measurement of efficiency. Biophysics (Nagoya-shi) 2012. [DOI: 10.1134/s0006350911060169] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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146
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Ginsenoside Rd stimulates the differentiation and mineralization of osteoblastic MC3T3-E1 cells by activating AMP-activated protein kinase via the BMP-2 signaling pathway. Fitoterapia 2012; 83:215-22. [DOI: 10.1016/j.fitote.2011.10.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 10/21/2011] [Accepted: 10/23/2011] [Indexed: 11/17/2022]
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Simpson CM, Calori GM, Giannoudis PV. Diabetes and fracture healing: the skeletal effects of diabetic drugs. Expert Opin Drug Saf 2011; 11:215-20. [PMID: 22145960 DOI: 10.1517/14740338.2012.639359] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Over 39,000 diabetic patients are surgically treated for trauma and orthopaedic injuries annually in the UK, yet the effects of diabetic medications on the skeletal system is an under researched and under acknowledged field. AREAS COVERED This review covers all English language novel experimental data reports investigating the effects of the main classes of diabetic drugs on the skeletal system, specifically their effects on fracture healing, located through the literature search engines Medline and Web of Science. EXPERT OPINION Post-surgical gylcaemic control is paramount in insulin-controlled type 1 diabetic patients. Data on pharmacological control compounds used in type 2 diabetes are limited. Reports to date indicate thiazolidinediones to exert anti-osteogenic effects, in contrast to the observed osteogenic effects of biguanides. Ongoing research is desirable to guide future clinical recommendations.
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Affiliation(s)
- Christopher M Simpson
- University of Leeds, Leeds Teaching Hospitals NHS Trust, School of Medicine, Academic Dept. of Trauma and Orthopaedics, Leeds, UK
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148
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Sullivan TR, Duque G, Keech AC, Herrmann M. An old friend in a new light: the role of osteocalcin in energy metabolism. Cardiovasc Ther 2011; 31:65-75. [PMID: 21975009 DOI: 10.1111/j.1755-5922.2011.00300.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Accumulating evidence suggests interactions between bone and energy metabolism, which may affect the risk of cardiovascular disease. Recent animal studies indicate that osteocalcin (OC) plays a key role in the coordinated regulation of glucose and insulin metabolism while insulin receptors on osteoblasts may regulate bone turnover and circulating OC levels. Association studies, weight loss interventions, and observational data lend some support to the existence and relevance of these mechanisms in humans. However, corroborating evidence from pharmacologic interventions in either bone or glucose metabolism is limited by the number, design, and complex pharmacological effects of the drugs used. Furthermore, such clinical trials are complicated by the alteration of metabolic feedback mechanisms in the insulin resistant state. Purpose-designed studies are needed to further establish the existence and significance of the role of OC and its subfractions in human insulin metabolism. In this review we summarize existing animal evidence regarding the role of OC and its subfractions in bone and energy metabolism and assess current clinical trial evidence relating to the significance and consequences of this relationship in humans.
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Affiliation(s)
- Tim R Sullivan
- Hornsby Kuring-gai Hospital, Northern Sydney Health Service, Hornsby, Australia
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149
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Sedlinsky C, Molinuevo MS, Cortizo AM, Tolosa MJ, Felice JI, Sbaraglini ML, Schurman L, McCarthy AD. Metformin prevents anti-osteogenic in vivo and ex vivo effects of rosiglitazone in rats. Eur J Pharmacol 2011; 668:477-85. [PMID: 21839072 DOI: 10.1016/j.ejphar.2011.07.033] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 06/30/2011] [Accepted: 07/24/2011] [Indexed: 02/08/2023]
Abstract
Long-term treatment with the insulin-sensitizer rosiglitazone reduces bone mass and increases fracture risk. We have recently shown that orally administered metformin stimulates bone reossification and increases the osteogenic potential of bone marrow progenitor cells (BMPC). In the present study we investigated the effect of a 2-week metformin and/or rosiglitazone treatment on bone repair, trabecular bone microarchitecture and BMPC osteogenic potential, in young male Sprague-Dawley rats. Compared to untreated controls, rosiglitazone monotherapy decreased bone regeneration, femoral metaphysis trabecular area, osteoblastic and osteocytic density, and TRAP activity associated with epiphyseal growth plates. It also decreased the ex vivo osteogenic commitment of BMPC, inducing an increase in PPARγ expression, and a decrease in Runx2/Cbfa1 expression, in AMP-kinase phosphorylation, and in osteoblastic differentiation and mineralization. After monotherapy with metformin, with the exception of PPARγ expression which was blunted, all of the above parameters were significantly increased (compared to untreated controls). Metformin/rosiglitazone co-treatment prevented all the in vivo and ex vivo anti-osteogenic effects of rosiglitazone monotherapy, with a reversion back to control levels of PPARγ, Runx2/Cbfa1 and AMP-kinase phosphorylation of BMPC. In vitro co-incubation of BMPC with metformin and compound C-an inhibitor of AMPK phosphorylation-abrogated the metformin-induced increase in type-1 collagen production, a marker of osteoblastic differentiation. In conclusion, in rodent models metformin not only induces direct osteogenic in vivo and ex vivo actions, but when it is administered orally in combination with rosiglitazone it can prevent several of the adverse effects that this thiazolidenedione shows on bone tissue.
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Affiliation(s)
- Claudia Sedlinsky
- GIOMM (Grupo de Investigación en Osteopatías y Metabolismo Mineral), Department of Biological Sciences, School of Exact Sciences, National University of La Plata, La Plata, Argentina
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150
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Takatani T, Minagawa M, Takatani R, Kinoshita K, Kohno Y. AMP-activated protein kinase attenuates Wnt/β-catenin signaling in human osteoblastic Saos-2 cells. Mol Cell Endocrinol 2011; 339:114-9. [PMID: 21501658 DOI: 10.1016/j.mce.2011.04.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 03/28/2011] [Accepted: 04/01/2011] [Indexed: 01/05/2023]
Abstract
AMP-activated protein kinase (AMPK) is a key sensor of cellular energetic conditions. Recent studies suggest that AMPK affects osteoblast differentiation, although its role and mechanism are not fully understood. One of the most important signals in osteoblast differentiation is the Wnt/β-catenin pathway which induces T-cell transcription factor 1 (TCF)-dependent transcription. Using human osteoblast-like Saos-2 cells, we determined whether AMPK modulates Wnt/β-catenin signaling in osteoblasts. Chemical activators of AMPK (AICAR [5-aminoimidazole-4-carboxamide riboside], metformin) suppressed Wnt3a-induced TCF-dependent transcriptional activity. Transactivation by Wnt was potentiated by inhibiting β-catenin degradation with lithium chloride (LiCl). LiCl-induced Wnt transactivation was suppressed by addition of metformin. Metformin increased the phosphorylation of β-catenin and decreased β-catenin protein levels leading to suppression of Wnt/β-catenin signaling. Our present study showed that AMPK attenuates Wnt/β-catenin signaling by reducing β-catenin protein levels in osteoblast-like cells.
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Affiliation(s)
- Tomozumi Takatani
- Department of Pediatrics, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8670, Japan.
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