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Lamarre M, Marcotte M, Laurin D, Furrer D, Vedel I, Tourigny A, Giguère A, Carmichael PH, Martines R, Morais J, Kröger E. Discontinuation of bisphosphonates in seniors: a systematic review on health outcomes. Arch Osteoporos 2021; 16:133. [PMID: 34524561 DOI: 10.1007/s11657-021-01000-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 09/05/2021] [Indexed: 02/03/2023]
Abstract
PURPOSE Bisphosphonates are used to treat osteoporosis. Despite their benefits on bone mineral density (BMD) and fractures, they have shown adverse effects, sometimes severe, during chronic use. Taken for several years, they achieve long-term bone retention, making deprescribing feasible. This review aimed to synthesize evidence on the success and health outcomes of deprescribing of bisphosphonates in seniors, aged over 60 years. METHODS The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, including articles in English, French, or German published before July 2020. Eligible studies included seniors having discontinued bisphosphonates and reported on health outcomes; some allowed meta-analyses on fracture risk. RESULTS The review included 9 RCTs and 9 cohort studies of moderate quality. Bisphosphonates were discontinued after 2 to 7 years of use, and BMD or fractures were assessed during follow-up of 0.5 to 5 years. A significant reduction in BMD after discontinuation was observed in 9 of 10 studies. Results on fracture risk after discontinuation are mitigated: 6 RCT extensions showed no increase in the risk of any osteoporotic fractures after discontinuation. Meta-analyses including 4 RCTs showed an increased odds ratio of vertebral fractures of 2.04 (95% CI, 1.39-2.99) among discontinuers. Results from 2 large cohort studies showed no increased risks of any osteoporotic or vertebral fractures, while 2 studies found increased fracture risks. CONCLUSION Bisphosphonates have successfully been discontinued low overall fracture risk after at least 3 years of use, but a risk for decreased BMD and increased vertebral fractures remained.
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Affiliation(s)
- Marianne Lamarre
- Faculté de médecine, Université Laval, Quebec City, Quebec, Canada
| | - Martine Marcotte
- Centre d'excellence sur le vieillissement de Québec, CIUSSS Capitale Nationale, Quebec City, Quebec, Canada
| | - Danielle Laurin
- Centre d'excellence sur le vieillissement de Québec, CIUSSS Capitale Nationale, Quebec City, Quebec, Canada.,Faculté de pharmacie, Université Laval, Quebec City, Quebec, Canada.,Institut sur le vieillissement et la participation sociale des aînés de l, Université Laval, Quebec City, Quebec, Canada.,Centre de recherche du CHU de Québec, Université Laval, Quebec City, Quebec, Canada.,VITAM Centre de recherche sur la santé durable, Quebec City, Quebec, Canada
| | - Daniela Furrer
- Centre d'excellence sur le vieillissement de Québec, CIUSSS Capitale Nationale, Quebec City, Quebec, Canada
| | - Isabelle Vedel
- Faculty of Medicine, McGill University, Montreal, Quebec, Canada
| | - André Tourigny
- Faculté de médecine, Université Laval, Quebec City, Quebec, Canada.,Centre d'excellence sur le vieillissement de Québec, CIUSSS Capitale Nationale, Quebec City, Quebec, Canada.,Institut sur le vieillissement et la participation sociale des aînés de l, Université Laval, Quebec City, Quebec, Canada.,Centre de recherche du CHU de Québec, Université Laval, Quebec City, Quebec, Canada.,VITAM Centre de recherche sur la santé durable, Quebec City, Quebec, Canada
| | - Anik Giguère
- Faculté de médecine, Université Laval, Quebec City, Quebec, Canada.,Centre d'excellence sur le vieillissement de Québec, CIUSSS Capitale Nationale, Quebec City, Quebec, Canada.,Centre de recherche du CHU de Québec, Université Laval, Quebec City, Quebec, Canada.,VITAM Centre de recherche sur la santé durable, Quebec City, Quebec, Canada
| | - Pierre-Hugues Carmichael
- Centre d'excellence sur le vieillissement de Québec, CIUSSS Capitale Nationale, Quebec City, Quebec, Canada.,VITAM Centre de recherche sur la santé durable, Quebec City, Quebec, Canada
| | - Rosa Martines
- Centre d'excellence sur le vieillissement de Québec, CIUSSS Capitale Nationale, Quebec City, Quebec, Canada
| | - José Morais
- Faculty of Medicine, McGill University, Montreal, Quebec, Canada
| | - Edeltraut Kröger
- Centre d'excellence sur le vieillissement de Québec, CIUSSS Capitale Nationale, Quebec City, Quebec, Canada. .,Faculté de pharmacie, Université Laval, Quebec City, Quebec, Canada. .,Centre de recherche du CHU de Québec, Université Laval, Quebec City, Quebec, Canada. .,VITAM Centre de recherche sur la santé durable, Quebec City, Quebec, Canada. .,Faculty of Medicine, McGill University, Montreal, Quebec, Canada.
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Dionne J, Lefèvre T, Bilodeau P, Lamarre M, Auger M. A quantitative analysis of the supercontraction-induced molecular disorientation of major ampullate spider silk. Phys Chem Chem Phys 2018; 19:31487-31498. [PMID: 29159351 DOI: 10.1039/c7cp05739c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spider silks exhibit remarkable properties, among which the so-called supercontraction, a physical phenomenon by which fibers undergo a longitudinal shrinkage and a radial swelling when exposed to water. The process is marked by a significant decrease in chain orientation resulting from plasticisation of the amorphous phase. Despite several studies that determined the Hermans orientation function, more quantitative data are required to be able to describe theoretically the macroscopic water-induced shrinkage from molecular reorganization. Here, we have examined the supercontraction of the major ampullate silk single fibers of Nephila clavipes (Nc) and Araneus diadematus (Ad) using polarized Raman spectromicroscopy. We determined the order parameters, the orientation distribution and the secondary structure content. Our data suggest that supercontraction induces a slight increase in β-sheet content, consistently with previous works. The β-sheet orientation is slightly affected by supercontraction compared to that of the amorphous phase, which becomes almost isotropic with shrinkage. Despite an initially lower orientation level, the Ad fiber shows a larger orientation decrease than Nc, consistently with its higher shrinkage amplitude. Although they share similar trends, absolute values of the orientation parameters from this work differ from those found in the literature. We took advantage of having determined the distribution of orientation to estimate the amplitude of shrinkage from changes in macromolecular size resulting from molecular disorientation. Our calculations show that more realistic models are needed to correlate molecular reorientation/refolding to macroscopic shrinkage. This work also underlines that more accurate data relative to molecular orientation are necessary.
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Affiliation(s)
- J Dionne
- Département de chimie, Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Université Laval, Pavillon Alexandre-Vachon, QC G1V 0A6, Canada.
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Marchand C, Bachand J, Périnêt J, Baraghis E, Lamarre M, Rivard GE, De Crescenzo G, Hoemann CD. C3, C5, and factor B bind to chitosan without complement activation. J Biomed Mater Res A 2010; 93:1429-41. [PMID: 19927329 DOI: 10.1002/jbm.a.32638] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Chitosan is a polycationic and biocompatible polysaccharide composed of glucosamine and N-acetyl glucosamine that is chemotactic for neutrophils and stimulates wound repair through mechanisms that remain unclear. It was previously shown that chitosan depletes complement proteins from plasma, suggesting that chitosan activates complement. Complement activation leads to cleavage of C5 to produce C5a, a neutrophil chemotactic factor. Here, we tested the hypothesis that chitosan generates C5a in human whole blood, citrated plasma, and serum. C5a fragment appeared in coagulating whole blood, and mixtures of chitosan-glycerol phosphate/whole blood, in parallel with platelet and thrombin activation. However, in plasma and serum, thrombin and chitosan-GP failed to generate C5a, although native C3, C5, and factor B adsorbed noncovalently to insoluble chitosan particles incubated in citrated plasma, serum, EDTA-serum and methylamine-treated plasma. By surface plasmon resonance, pure C3 adsorbed to chitosan. The profile of serum factors associating with chitosan was consistent with a model in which anionic blood proteins with a pI lower than the pK(0) 6.78 of chitosan (the upper limit of chitosan pK(a)) associate electrostatically with cationic chitosan particles. Zymosan, a yeast ghost particle, activated complement in serum and citrated plasma, but not in EDTA-serum or methylamine plasma, to generate fluid-phase C5a, while C3b formed covalent cross-links with zymosan-associated proteins and became rapidly cleaved to iC3b, with factor Bb stably associated. These data demonstrate that chitosan is a nonreactive biomaterial that does not directly activate complement, and provide a novel basis for predicting anionic serum protein-chitosan interactions.
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Affiliation(s)
- C Marchand
- Institute of Biomedical Engineering, Ecole Polytechnique, Montréal, Quebec, Canada H3C 3A7
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