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Effects of zoledronic acid on physiologic bone remodeling of condylar part of TMJ: a radiologic and histomorphometric examination in rabbits. ScientificWorldJournal 2014; 2014:649026. [PMID: 24688415 PMCID: PMC3918717 DOI: 10.1155/2014/649026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 11/12/2013] [Indexed: 12/28/2022] Open
Abstract
Objective. The purpose of the present study is to evaluate the effects of systemically administered zoledronic acid (ZA) on the physiological bone remodeling and the microarchitectural parameters of the condylar part of TMJ in a rabbit model.
Study Design. Thirty skeletally mature male New Zealand white rabbits were randomly divided into two groups. The experimental group was administered an intravenous, single dose of 0.1 mg/kg ZA diluted with 15 mL of saline in a 15-minute perfusion with an infusion pump. The control group was administered only saline infusion for 15 minutes. All rabbits were sacrificed on the 21st postoperative day. Radiodensitometric and histomorphometric examinations were performed on the harvested mandibular condyles. The data were analyzed statistically.
Results. Radiodensitometric findings showed that ZA treatment resulted in a significant increase in the mineralization of mandibular condyle. This result was supported by the histomorphometric findings.
Conclusion. The present study has revealed that a temporary delay in the physiological bone remodeling using single dose of ZA increases bone mineral content and makes the microarchitecture of the mandibular condyle more compact. These effects may be regarded as base data and considered in numerous clinical situations including TMJ.
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Martin RM, Correa PHS. Bone quality and osteoporosis therapy. ACTA ACUST UNITED AC 2011; 54:186-99. [PMID: 20485908 DOI: 10.1590/s0004-27302010000200015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 02/28/2010] [Indexed: 01/10/2023]
Abstract
Although BMD measured by DXA is a useful clinical tool for osteoporosis diagnosis, changes resulting from osteoporosis treatment only partially explain the observed reduction in fractures. Several other bone properties that influence its resistance to fractures and explain this discrepancy have been defined as "bone quality". Bone quality is determined by its structural and material properties and orchestrated by bone turnover, a continuous process of renewal through which old or damaged bone is replaced by a mechanically healthy bone and calcium homeostasis is maintained. Bone structural properties include its geometry (size and shape) and microarchitecture (trabecular architecture and cortical porosity), while bone material properties include its mineral and collagen composition as well as microdamage and its repair. This review aims to update concepts surrounding bone quality and how drugs employed to treat osteoporosis might influence them.
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Fenton TR, Tough SC, Lyon AW, Eliasziw M, Hanley DA. Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill's epidemiologic criteria for causality. Nutr J 2011; 10:41. [PMID: 21529374 PMCID: PMC3114717 DOI: 10.1186/1475-2891-10-41] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 04/30/2011] [Indexed: 01/19/2023] Open
Abstract
Background Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria. Methods Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined. Results Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies did not provide evidence for an adverse role of phosphate, milk, and grain foods in osteoporosis. Conclusions A causal association between dietary acid load and osteoporotic bone disease is not supported by evidence and there is no evidence that an alkaline diet is protective of bone health.
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Affiliation(s)
- Tanis R Fenton
- Department of Community Health Sciences, University of Calgary, Calgary, AB, Canada.
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Fenton TR, Eliasziw M, Tough SC, Lyon AW, Brown JP, Hanley DA. Low urine pH and acid excretion do not predict bone fractures or the loss of bone mineral density: a prospective cohort study. BMC Musculoskelet Disord 2010; 11:88. [PMID: 20459740 PMCID: PMC2890599 DOI: 10.1186/1471-2474-11-88] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 05/10/2010] [Indexed: 11/25/2022] Open
Abstract
Background The acid-ash hypothesis, the alkaline diet, and related products are marketed to the general public. Websites, lay literature, and direct mail marketing encourage people to measure their urine pH to assess their health status and their risk of osteoporosis. The objectives of this study were to determine whether 1) low urine pH, or 2) acid excretion in urine [sulfate + chloride + 1.8x phosphate + organic acids] minus [sodium + potassium + 2x calcium + 2x magnesium mEq] in fasting morning urine predict: a) fragility fractures; and b) five-year change of bone mineral density (BMD) in adults. Methods Design: Cohort study: the prospective population-based Canadian Multicentre Osteoporosis Study. Multiple logistic regression was used to examine associations between acid excretion (urine pH and urine acid excretion) in fasting morning with the incidence of fractures (6804 person years). Multiple linear regression was used to examine associations between acid excretion with changes in BMD over 5-years at three sites: lumbar spine, femoral neck, and total hip (n = 651). Potential confounders controlled included: age, gender, family history of osteoporosis, physical activity, smoking, calcium intake, vitamin D status, estrogen status, medications, renal function, urine creatinine, body mass index, and change of body mass index. Results There were no associations between either urine pH or acid excretion and either the incidence of fractures or change of BMD after adjustment for confounders. Conclusion Urine pH and urine acid excretion do not predict osteoporosis risk.
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Affiliation(s)
- Tanis R Fenton
- Department of Community Health Sciences, Faculty of Medicine, University of Calgary TRW Building, 3rd Floor, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada.
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Kumar S, Matheny CJ, Hoffman SJ, Marquis RW, Schultz M, Liang X, Vasko JA, Stroup GB, Vaden VR, Haley H, Fox J, DelMar EG, Nemeth EF, Lago AM, Callahan JF, Bhatnagar P, Huffman WF, Gowen M, Yi B, Danoff TM, Fitzpatrick LA. An orally active calcium-sensing receptor antagonist that transiently increases plasma concentrations of PTH and stimulates bone formation. Bone 2010; 46:534-42. [PMID: 19786130 DOI: 10.1016/j.bone.2009.09.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 08/24/2009] [Accepted: 09/22/2009] [Indexed: 11/17/2022]
Abstract
Daily subcutaneous administration of exogenous parathyroid hormone (PTH) promotes bone formation in patients with osteoporosis. Here we describe two novel, short-acting calcium-sensing receptor antagonists (SB-423562 and its orally bioavailable precursor, SB-423557) that elicit transient PTH release from the parathyroid gland in several preclinical species and in humans. In an ovariectomized rat model of bone loss, daily oral administration of SB-423557 promoted bone formation and improved parameters of bone strength at lumbar spine, proximal tibia and midshaft femur. Chronic administration of SB-423557 did not increase parathyroid cell proliferation in rats. In healthy human volunteers, single doses of intravenous SB-423562 and oral SB-423557 elicited transient elevations of endogenous PTH concentrations in a profile similar to that observed with subcutaneously administered PTH. Both agents were well tolerated in humans. Transient increases in serum calcium, an expected effect of increased parathyroid hormone concentrations, were observed post-dose at the higher doses of SB-423557 studied. These data constitute an early proof of principle in humans and provide the basis for further development of this class of compound as a novel, orally administered bone-forming treatment for osteoporosis.
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Affiliation(s)
- Sanjay Kumar
- GlaxoSmithKline, UM 2230, 709 Swedeland Road, King of Prussia, PA 19406-2711, USA
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Rahmani P, Morin S. Prevention of osteoporosis-related fractures among postmenopausal women and older men. CMAJ 2009; 181:815-20. [PMID: 19841053 DOI: 10.1503/cmaj.080709] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Poupak Rahmani
- Department of Medicine, McGill University, Montréal, Que
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Fenton TR, Lyon AW, Eliasziw M, Tough SC, Hanley DA. Phosphate decreases urine calcium and increases calcium balance: a meta-analysis of the osteoporosis acid-ash diet hypothesis. Nutr J 2009; 8:41. [PMID: 19754972 PMCID: PMC2761938 DOI: 10.1186/1475-2891-8-41] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 09/15/2009] [Indexed: 11/30/2022] Open
Abstract
Background The acid-ash hypothesis posits that increased excretion of "acidic" ions derived from the diet, such as phosphate, contributes to net acidic ion excretion, urine calcium excretion, demineralization of bone, and osteoporosis. The public is advised by various media to follow an alkaline diet to lower their acidic ion intakes. The objectives of this meta-analysis were to quantify the contribution of phosphate to bone loss in healthy adult subjects; specifically, a) to assess the effect of supplemental dietary phosphate on urine calcium, calcium balance, and markers of bone metabolism; and to assess whether these affects are altered by the b) level of calcium intake, c) the degree of protonation of the phosphate. Methods Literature was identified through computerized searches regarding phosphate with surrogate and/or direct markers of bone health, and was assessed for methodological quality. Multiple linear regression analyses, weighted for sample size, were used to combine the study results. Tests of interaction included stratification by calcium intake and degree of protonation of the phosphate supplement. Results Twelve studies including 30 intervention arms manipulated 269 subjects' phosphate intakes. Three studies reported net acid excretion. All of the meta-analyses demonstrated significant decreases in urine calcium excretion in response to phosphate supplements whether the calcium intake was high or low, regardless of the degree of protonation of the phosphate supplement. None of the meta-analyses revealed lower calcium balance in response to increased phosphate intakes, whether the calcium intake was high or low, or the composition of the phosphate supplement. Conclusion All of the findings from this meta-analysis were contrary to the acid ash hypothesis. Higher phosphate intakes were associated with decreased urine calcium and increased calcium retention. This meta-analysis did not find evidence that phosphate intake contributes to demineralization of bone or to bone calcium excretion in the urine. Dietary advice that dairy products, meats, and grains are detrimental to bone health due to "acidic" phosphate content needs reassessment. There is no evidence that higher phosphate intakes are detrimental to bone health.
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Affiliation(s)
- Tanis R Fenton
- Clinical Nutrition, Alberta Health Services, Calgary, AB, Canada.
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Leeming DJ, Henriksen K, Byrjalsen I, Qvist P, Madsen SH, Garnero P, Karsdal MA. Is bone quality associated with collagen age? Osteoporos Int 2009; 20:1461-70. [PMID: 19330423 DOI: 10.1007/s00198-009-0904-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 02/27/2009] [Indexed: 12/27/2022]
Abstract
The World Health Organization defines osteoporosis as a systemic disease characterized by decreased bone tissue mass and microarchitectural deterioration, resulting in increased fracture risk. Since this statement, a significant amount of data has been generated showing that these two factors do not cover all risks for fracture. Other independent clinical factors, such as age, as well as aspects related to qualitative changes in bone tissue, are believed to play an important role. The term "bone quality" encompasses a variety of parameters, including the extent of mineralization, the number and distribution of microfractures, the extent of osteocyte apoptosis, and changes in collagen properties. The major mechanism controlling these qualitative factors is bone remodeling, which is tightly regulated by the osteoclast/osteoblast activity. We focus on the relationship between bone remodeling and changes in collagen properties, especially the extent of one posttranslational modification. In vivo, measurements of the ratio between native and isomerized C-telopeptides of type I collagen provides an index of bone matrix age. Current preclinical and clinical studies suggests that this urinary ratio provides information about bone strength and fracture risk independent of bone mineral density and that it responds differently according to the type of therapy regulating bone turnover.
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Affiliation(s)
- D J Leeming
- Nordic Bioscience, Herlev Hovedgade 207, 2730, Herlev, Denmark.
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Abstract
Denosumab (anti-receptor activator of nuclear factor-kappaB ligand antibody) is a novel agent, a fully human monoclonal antibody that inhibits osteoclastic-medicated bone resorption by binding to osteoblast-produced RANKL. By reducing RANKL binding to the osteoclast receptor RANK, bone resorption and turnover decrease. In phase 2 dose-ranging studies, denosumab had a rapid onset and offset effect. Also, in patients who had received 2 years of denosumab and were discontinued for the third year, rechallenge with denosumab during the fourth year demonstrated a return of responsiveness to denosumab that mimicked the initial treatment. Phase 3 pivotal fracture data were recently presented with positive outcome data; denosumab (60 mg subcutaneously every 6 months) significantly reduced vertebral, nonvertebral, and hip fracture risk compared with placebo, and had an excellent safety profile through 3 years of use. Denosumab will offer a novel approach to managing postmenopausal osteoporosis, one that should be associated with a high adherence rate and global fracture risk reduction.
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Affiliation(s)
- Paul D Miller
- Department of Medicine, University of Colorado Health Sciences Center, Colorado Center for Bone Research, 3190 South Wadsworth Boulevard, Lakewood, CO 80227, USA.
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Abstract
Bone-active agents that decrease bone turnover (the anti-resorptive agents) have been, to date, the most thoroughly studied pharmacological agents for the management of osteoporosis in a variety of populations - postmenopausal, male, and glucocorticoid-induced osteoporosis - and have received both Food and Drug Administration (FDA) and Committee for Medicinal Products for Human Use (CHMP) as well as other worldwide registrations for the management of these conditions. While the mechanisms of action of 'anti-resorptives' as a class differ, their effect on increasing bone strength and reducing the risk of fragility fractures share common pathways: an increase in bone mineral content, and a reduction in bone turnover. Within the category of anti-resorptives: estrogen, selective estrogen receptor modulators, tibolone, calcitonin, bisphosphonates and denosumab all reduce vertebral fractures risk, but differ in their ability to reduce the risk of non-vertebral fractures in randomized clinical trials. This chapter will discuss the data on these effects for each class of anti-resorptive agent.
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Affiliation(s)
- Paul D Miller
- Colorado Center for Bone Research, Lakewood, Colorado 80227, USA.
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Laroche M. Treatment of osteoporosis: all the questions we still cannot answer. Am J Med 2008; 121:744-7. [PMID: 18724959 DOI: 10.1016/j.amjmed.2008.03.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 03/19/2008] [Accepted: 03/19/2008] [Indexed: 10/21/2022]
Abstract
Many questions remain with regard to the treatment of osteoporosis. The increase in bone mineral density due to bisphosphonates accounts for only a quarter of their antifracture action. The studies of bone mineral density equivalences that have validated certain modes of administration are therefore not relevant. No comparative study on the same patient cohort has been carried out, and the inclusion criteria of the pilot studies on the drugs currently available are all different. This makes any comparison impossible, and thus, the choice of treatment is subjective. Certain combinations (antiresorptive drugs and anabolic agents) are logical, but no major study is available to validate them. Drugs with a long latency period could interfere with later treatments or allow therapeutic windows, but the data in the literature in support of these hypotheses are scarce. The osteoporotic patient will require treatment for 10 to 30 years, depending on the age at diagnosis, but the available data on the efficacy and nontoxicity of the drugs are based on studies of a duration of only 3 or 5 years.
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Affiliation(s)
- Michel Laroche
- Service de Rhumatologie, Hôpital Rangueil-Larrey, Toulouse, France.
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Morin S, Rahme E, Behlouli H, Tenenhouse A, Goltzman D, Pilote L. Effectiveness of antiresorptive agents in the prevention of recurrent hip fractures. Osteoporos Int 2007; 18:1625-32. [PMID: 17634854 DOI: 10.1007/s00198-007-0421-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 06/13/2007] [Indexed: 02/07/2023]
Abstract
UNLABELLED Hip fracture is associated with recurrent fractures and increased mortality. The results of our retrospective cohort study support the use of antiresorptive agents to prevent recurrent hip fractures in this population. INTRODUCTION Hip fracture, the most serious consequence of osteoporosis, is associated with recurrent fractures and increased mortality. Antiresorptive therapy has proven efficacy in the prevention of fractures after vertebral fractures. It is unknown if it can prevent recurrent fractures after a hip fracture. METHODS We designed a population based, retrospective cohort study, using administrative databases and identified patients hospitalized for a hip fracture between 1996 and 2002. The exposure was defined as being dispensed a prescription for an antiresorptive agent at any time following discharge. Multivariate Cox regression models were used to estimate the hazard ratio of recurrent hip fracture. Subgroup and propensity score analyses were performed. RESULTS A total of 20,644 patients were identified; 6,779 filled a prescription for antiresorptive agents. There were 992 recurrent hip fractures. Patients exposed to antiresorptives had a 26% reduction in the rate of recurrent fractures (adjusted hazard ratio 0.74; 95% CI, 0.64-0.86) compared to patients who were not. All subgroups experienced a reduction in recurrent fracture, except the very elderly. Propensity score analyses were consistent with the main analysis. CONCLUSIONS Antiresorptive therapy reduces the risk of recurrent hip fractures in elderly patients. These results provide evidence that this therapy should be considered for secondary prevention of hip fractures.
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Affiliation(s)
- S Morin
- Division of Internal Medicine, McGill University Health Center (MUHC), 1650 Cedar Ave, Room B2-118, Montreal, QC, H3G 1A4, Canada.
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