Effectiveness of bisphosphonates on nonvertebral and hip fractures in the first year of therapy: The risedronate and alendronate (REAL) cohort study

INTRODUCTION: Randomized clinical trials have shown that risedronate and alendronate reduce fractures among women with osteoporosis. The aim of this observational study was to observe, in clinical practice, the incidence of hip and nonvertebral fractures among women in the year following initiation of once-a-week dosing of either risedronate or alendronate. METHODS: Using records of health service utilization from July 2002 through September 2004, we created two cohorts: women (ages 65 and over) receiving risedronate (n = 12,215) or alendronate (n = 21,615). Cox proportional hazard modeling was used to compare the annual incidence of nonvertebral fractures and of hip fractures between cohorts, adjusting for potential differences in risk factors for fractures. RESULTS: There were 507 nonvertebral fractures and 109 hip fractures. Through one year of therapy, the incidence of nonvertebral fractures in the risedronate cohort (2.0%) was 18% lower (95% CI 2% – 32%) than in the alendronate cohort (2.3%). The incidence of hip fractures in the risedronate cohort (0.4%) was 43% lower (95% CI 13% – 63%) than in the alendronate cohort (0.6%). These results were consistent across a number of sensitivity analyses. CONCLUSION: Patients receiving risedronate have lower rates of hip and nonvertebral fractures during their first year of therapy than patients receiving alendronate

Roles of Electrostatics and Conformation in Protein-Crystal Interactions

In vitro studies have shown that the phosphoprotein osteopontin (OPN) inhibits the nucleation and growth of hydroxyapatite (HA) and other biominerals. In vivo, OPN is believed to prevent the calcification of soft tissues. However, the nature of the interaction between OPN and HA is not understood. In the computational part of the present study, we used molecular dynamics simulations to predict the adsorption of 19 peptides, each 16 amino acids long and collectively covering the entire sequence of OPN, to the {100} face of HA. This analysis showed that there is an inverse relationship between predicted strength of adsorption and peptide isoelectric point (P<0.0001). Analysis of the OPN sequence by PONDR (Predictor of Naturally Disordered Regions) indicated that OPN sequences predicted to adsorb well to HA are highly disordered. In the experimental part of the study, we synthesized phosphorylated and non-phosphorylated peptides corresponding to OPN sequences 65–80 (pSHDHMDDDDDDDDDGD) and 220–235 (pSHEpSTEQSDAIDpSAEK). In agreement with the PONDR analysis, these were shown by circular dichroism spectroscopy to be largely disordered. A constant-composition/seeded growth assay was used to assess the HA-inhibiting potencies of the synthetic peptides. The phosphorylated versions of OPN65-80 (IC50 = 1.93 µg/ml) and OPN220-235 (IC50 = 1.48 µg/ml) are potent inhibitors of HA growth, as is the nonphosphorylated version of OPN65-80 (IC50 = 2.97 µg/ml); the nonphosphorylated version of OPN220-235 has no measurable inhibitory activity. These findings suggest that the adsorption of acidic proteins to Ca2+-rich crystal faces of biominerals is governed by electrostatics and is facilitated by conformational flexibility of the polypeptide chain

Surface Aggregation of Urinary Proteins and Aspartic Acid-Rich Peptides on the Faces of Calcium Oxalate Monohydrate Investigated by In Situ Force Microscopy

The growth of calcium oxalate monohydrate in the presence of Tamm-Horsfall protein (THP), osteopontin, and the 27-residue synthetic peptides (DDDS)6DDD and (DDDG)6DDD (D = aspartic acid, S = serine, and G = glycine) was investigated via in situ atomic force microscopy. The results show that these four growth modulators create extensive deposits on the crystal faces. Depending on the modulator and crystal face, these deposits can occur as discrete aggregates, filamentary structures, or uniform coatings. These proteinaceous films can lead to either the inhibition of or an increase in the step speeds (with respect to the impurity-free system), depending on a range of factors that include peptide or protein concentration, supersaturation, and ionic strength. While THP and the linear peptides act, respectively, to exclusively increase and inhibit growth on the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( {\bar{1}01} \right)$$\end{document} face, both exhibit dual functionality on the (010) face, inhibiting growth at low supersaturation or high modulator concentration and accelerating growth at high supersaturation or low modulator concentration. Based on analyses of growth morphologies and dependencies of step speeds on supersaturation and protein or peptide concentration, we propose a picture of growth modulation that accounts for the observations in terms of the strength of binding to the surfaces and steps and the interplay of electrostatic and solvent-induced forces at the crystal surface

Effect of Longâ Term Oral Bisphosphonates on Implant Wound Healing: Literature Review and a Case Report

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141603/1/jper0584.pd

Effects of discontinuing oral bisphosphonate treatments for postmenopausal osteoporosis on bone turnover markers and bone density

The antiresorptive potency varies between different bisphosphonates. We investigated the effect of stopping oral bisphosphonate treatment for postmenopausal osteoporosis (ibandronate, alendronate, risedronate) on BTMs and BMD. After stopping treatment, all three groups showed an increase in BTMs and a decrease in hip BMD; however, none returned to pre-treatment baseline values. INTRODUCTION: Bisphosphonates (BPs) continue to suppress bone turnover markers (BTMs) after treatment has stopped, leading to the suggestion that a pause in treatment could be considered for low-risk patients. Indirect comparisons suggest that after cessation of treatment, the effects on bone may differ between drugs. We investigated the effects of stopping oral BP treatments for postmenopausal osteoporosis on BTMs and bone mineral density (BMD). METHODS: We studied postmenopausal osteoporotic women who had previously taken part in a 2-year randomised study of three oral BPs (ibandronate, alendronate, or risedronate). At the end of the study, women with hip BMD T-score > - 2.5 and considered clinically appropriate to discontinue treatment were invited to participate in a further 2-year observational study. Biochemical response was assessed using BTMs, and BMD was measured by dual-energy X-ray absorptiometry. RESULTS: All BTMs increased after treatment withdrawal but remained below the pre-treatment baseline with less suppression of BTMs for the risedronate group compared to alendronate and ibandronate up to 48 weeks. There was no difference between the BP groups 96 weeks after stopping treatment. The change in BMD during the 96 weeks after stopping treatment was - 1.6% (95% CI - 1.9 to - 1.2, P < 0.001) for the total hip and - 0.6% (95% CI - 1.1 to - 0.2, P = 0.17) at the lumbar spine with no difference between the three BP groups (P = 0.85 and P = 0.48, respectively). CONCLUSION: For all treatment groups, there was an increase in BTMs and a decrease in hip BMD after stopping BPs for 2 years; however, none returned to pre-treatment baseline values

Treatment of OPG-deficient mice with WP9QY, a RANKL-binding peptide, recovers alveolar bone loss by suppressing osteoclastogenesis and enhancing osteoblastogenesis.

Osteoblasts express two key molecules for osteoclast differentiation, receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG), a soluble decoy receptor for RANKL. RANKL induces osteoclastogenesis, while OPG inhibits it by blocking the binding of RANKL to RANK, a cellular receptor of RANKL. OPG-deficient (OPG–/–) mice exhibit severe alveolar bone loss with enhanced bone resorption. WP9QY (W9) peptide binds to RANKL and blocks RANKL-induced osteoclastogenesis. W9 is also reported to stimulate bone formation in vivo. Here, we show that treatment with W9 restores alveolar bone loss in OPG–/–mice by suppressing osteoclastogenesis and enhancing osteoblastogenesis. Administration of W9 or risedronate, a bisphosphonate, to OPG–/–mice significantly decreased the osteoclast number in the alveolar bone. Interestingly, treatment with W9, but not risedronate, enhanced Wnt/β-catenin signaling and induced alveolar bone formation in OPG–/–mice. Expression of sclerostin, an inhibitor of Wnt/β-catenin signaling, was significantly lower in tibiae of OPG–/–mice than in wild-type mice. Treatment with risedronate recovered sclerostin expression in OPG–/–mice, while W9 treatment further suppressed sclerostin expression. Histomorphometric analysis confirmed that bone formation-related parameters in OPG–/–mice, such as osteoblast number, osteoblast surface and osteoid surface, were increased by W9 administration but not by risedronate administration. These results suggest that treatment of OPG–/–mice with W9 suppressed osteoclastogenesis by inhibiting RANKL signaling and enhanced osteoblastogenesis by attenuating sclerostin expression in the alveolar bone. Taken together, W9 may be a useful drug to prevent alveolar bone loss in periodontitis