Compactin and simvastatin, but not pravastatin, induce bone morphogenetic protein-2 in human osteosarcoma cells

Evaluating Bioassays for the Determination of Simvastatin's Osteogenic Activity: A Systematic Review

OBJECTIVE

Osteogenic differentiation is a complex process, and its analysis requires several biomarkers. Allied with this, there are no standardized bioassays to monitor the activity of simvastatin in osteogenesis in vitro. Therefore, identifying the most efficient and sensitive bioassays may enhance the quality of in vitro studies, bridging the gap with in vivo findings, saving time and resources, and benefiting the community. This systematic review aimed to determine the most efficient bioassay for simvastatin's osteogenic activity in vitro, in terms of sensitivity.

MATERIALS AND METHODS

In vitro studies evaluating undifferentiated mesenchymal cells treated with simvastatin were considered eligible. References were selected in a two-phase process. Electronic databases and the grey literature were screened up to September 2023. The Office of Health Assessment and Translation (OHAT) tool was used to assess the risk of bias. Certainty in cumulative evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria. Data were analyzed considering extracellular matrix mineralization, alkaline phosphatase, and the expression of potential target genes, such as bone morphogenetic protein-2 (BMP-2), collagen type I, Runt-related transcription factor 2, osterix, osteocalcin, and osteopontin.

RESULTS

Fourteen studies were included. A "probably low" or a "definitely low" risk of bias was assigned to the included studies. The simvastatin concentration ranged from 0.1 nM to 10 µM. Considering a minimum 4-fold increase, simvastatin caused robust mineralization of the extracellular matrix in four studies (4.0-, 4.4-, 5.0-, and 39.5-fold). Moreover, simvastatin substantially increased BMP-2 expression in mesenchymal cells in three studies (4-, 11-, and 19-fold).

CONCLUSION

Therefore, mineralization of the extracellular matrix and BMP-2 expression in mesenchymal cells are the most efficient bioassays for determining the osteogenic activity of simvastatin in vitro (high certainty level). These findings provide a standardized approach that can enhance the reliability and comparability of in vitro studies, bridging the gap with in vivo research and optimizing resources in the field of bone regeneration.

Comparison of the pleiotropic effect of atorvastatin and rosuvastatin on postmenopausal changes in bone turnover: A randomized comparative study

BACKGROUND

Statins are the first-line treatment for dyslipidemia, which is a major modifiable risk factor for atherosclerotic cardiovascular disease. Studies have shown that in addition to the beneficial lipid-lowering effect, statins also exhibit a number of pleiotropic effects that may find application in other diseases, including osteoporosis. This study aimed to assess the effect of statins on bone turnover, as measured by the concentration of bone turnover markers, and to compare the effect of atorvastatin as a lipophilic statin and rosuvastatin as a hydrophilic statin.

METHODS

This study included 34 postmenopausal women aged < 65 years with newly diagnosed dyslipidemia requiring statin therapy. Patients were randomly assigned to receive a statin drug. Statins were initiated at standard doses of 5 to 10 mg of rosuvastatin and 20 mg of atorvastatin. The levels of C-terminal telopeptide of type I collagen as a bone resorption marker and N-terminal propeptide of procollagen type I as a marker of bone formation, lipid concentrations and other biochemical parameters were assessed at baseline and after 6 and twelve months of treatment.

RESULTS

There were no statistically significant differences between the levels of bone turnover markers before and 6 months after statin implementation (P > .05) - for all patients or subgroups according to statin use. Analysis of the results showed that after 12 months, there was a statistically significant decrease in N-terminal propeptide of procollagen type I concentration in all subjects (P = .004). By statin subgroup, a statistically significant decrease in N-terminal propeptide of procollagen type I was observed only in patients receiving rosuvastatin (P = .012) and not in those receiving atorvastatin (P = .25). Moreover, changes in bone turnover markers did not correlate with changes in lipid concentrations.

CONCLUSIONS

These results may indicate the superiority of atorvastatin over rosuvastatin in inhibiting adverse changes in bone turnover in postmenopausal women. Confirmed by studies involving a larger population, the observed differences might find particular applications in clinical practice, and the choice of atorvastatin over rosuvastatin for women could be considered in the early postmenopausal period to reduce the risk of osteoporosis and subsequent osteoporotic fractures.

The effects of popular diets on bone health in the past decade: a narrative review

Bone health encompasses not only bone mineral density but also bone architecture and mechanical properties that can impact bone strength. While specific dietary interventions have been proposed to treat various diseases such as obesity and diabetes, their effects on bone health remain unclear. The aim of this review is to examine literature published in the past decade, summarize the effects of currently popular diets on bone health, elucidate underlying mechanisms, and provide solutions to neutralize the side effects. The diets discussed in this review include a ketogenic diet (KD), a Mediterranean diet (MD), caloric restriction (CR), a high-protein diet (HP), and intermittent fasting (IF). Although detrimental effects on bone health have been noticed in the KD and CR diets, it is still controversial, while the MD and HP diets have shown protective effects, and the effects of IF diets are still uncertain. The mechanism of these effects and the attenuation methods have gained attention and have been discussed in recent years: the KD diet interrupts energy balance and calcium metabolism, which reduces bone quality. Ginsenoside-Rb2, metformin, and simvastatin have been shown to attenuate bone loss during KD. The CR diet influences energy imbalance, glucocorticoid levels, and adipose tissue, causing bone loss. Adequate vitamin D and calcium supplementation and exercise training can attenuate these effects. The olive oil in the MD may be an effective component that protects bone health. HP diets also have components that protect bone health, but their mechanism requires further investigation. In IF, animal studies have shown detrimental effects on bone health, while human studies have not. Therefore, the effects of diets on bone health vary accordingly.

Differential effect of atorvastatin and pravastatin on thoracic spine attenuation: A sub-analysis of a randomized clinical trial

BACKGROUND

Statins reduce cardiovascular events and may improve bone mineral density.

METHODS

We conducted a sub-analysis of a randomized clinical trial that investigated the differential effect of moderate vs intensive low-density lipoprotein cholesterol (LDL-C) lowering therapies on coronary artery calcium (CAC) scores, and used the acquired images to assess the change in radiological attenuation of selected thoracic vertebrae. Baseline and 12-month unenhanced chest CT scans were performed in 420 hyperlipidemic, postmenopausal women randomized to atorvastatin (ATV) 80 mg/day or pravastatin (PRV) 40 mg/day in the Beyond Endorsed Lipid Lowering with Electron Beam Tomography Scanning (BELLES) trial. Bone attenuation was measured in three contiguous thoracic vertebrae at baseline and 12 months.

RESULTS

There were no differences in baseline demographic and clinical characteristics between treatment arms. The median percent lowering (interquartile range) in LDL-C was significantly greater with ATV than PRV [-53 (-69 to 20)% vs -28 (-55 to 74)%, p < 0.001], although the CAC score change was similar [12 (-63 to 208)% vs 13 (-75 to 358)%; p = 0.44]. At follow-up, the median bone attenuation loss was significantly greater with PRV than with ATV [-2.6 (-27 to 11)% vs 0 (-11 to 25)%; p < 0.001]. The attenuation loss in the PRV group was comparable to that of a historical untreated general population sample. In the entire cohort, the changes in LDL-C and total cholesterol were inversely correlated with bone attenuation change (p < 0.01). In adjusted multivariable linear regression analyses, race and percent change in LDL-C were independent predictors of bone attenuation change. Age, body mass index, history of smoking, diabetes mellitus, hypertension, peripheral vascular disease, or hormone replacement therapy did not affect percent change in BMD.

CONCLUSIONS

These findings support the hypothesis that there is an interaction between bone and cardiometabolic health and that intensive lipid lowering has a beneficial effect on bone health.

The Development of Thermoresponsive Polymeric Simvastatin Prodrug for the Treatment of Experimental Periodontitis in Rats

Periodontitis (PD) is a severe inflammatory gum pathology that damages the periodontal soft tissue and bone. It is highly prevalent in the US, affecting more than 47% of adults. Besides routine scaling and root planing, there are few effective treatments for PD. Developed as an effective treatment for hyperlipidemia, simvastatin (SIM) is also known for its well-established anti-inflammatory and osteogenic properties, suggesting its potential utility in treating PD. Its clinical translation, however, has been impeded by its poor water-solubility, lack of osteotropicity, and side effects (e.g., hepatoxicity) associated with systemic exposure. To address these challenges, an N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-based thermoresponsive polymeric prodrug of SIM (ProGel-SIM) was developed as a local therapy for PD. Its aqueous solution is free-flowing at 4 °C and transitions into a hydrogel at ∼30 °C, allowing for easy local application and retention. After a thorough characterization of its physicochemical properties, ProGel-SIM was administered weekly into the periodontal pocket of an experimental rat model of PD. At 3 weeks post initiation of the treatment, the animals were euthanized with palate isolated for μ-CT and histological analyses. When compared to dose equivalent simvastatin acid (SMA, active form of SIM) treatment, the rats in the ProGel-SIM treated group showed significantly higher periodontal bone volume (0.34 mm3 vs 0.20 mm3, P = 0.0161) and less neutrophil (PMN) infiltration (P < 0.0001) and IL-1β secretion (P = 0.0036). No measurable side effect was observed. Collectively, these results suggest that ProGel-SIM may be developed as a promising drug candidate for the effective clinical treatment of PD.

Farnesyl diphosphate synthase promotes cell proliferation by regulating gene expression and alternative splicing profiles in HeLa cells

Farnesyl diphosphate synthase (FDPS), an essential enzyme involved in the mevalonate pathway, is implicated in various diseases, including multiple types of cancer. As an RNA-binding protein (RBP), FDPS is also involved in transcriptional and post-transcriptional regulation. However, to the best of our knowledge, transcriptome-wide targets of FDPS still remain unknown. In the present study, FDPS expression patterns in pan-cancer were analyzed. In addition, it was investigated how FDPS overexpression (FDPS-OE) regulates the transcriptome in HeLa cells. FDPS-OE increased the proliferation rate in HeLa cells by MTT assay. Using transcriptome-wide high throughput sequencing and bioinformatics analysis, it was found that FDPS upregulated the expression levels of genes enriched in cell proliferation and extracellular matrix organization, including the laminin subunit γ2, interferon-induced proteins with tetratricopeptide repeats 2 and matrix metallopeptidase 19 genes. According to alternative splicing (AS) analysis, FDPS modulated the splicing patterns of the bone morphogenic protein 1, semaphorin 4D, annexin A2 and sirtuin 2 genes, which are enriched in the cell cycle and DNA repair, and are related to cell proliferation. To corroborate the FDPS-regulated transcriptome findings, FDPS was overexpressed in human osteosarcoma cells. Differentially expressed genes and regulated AS genes in the cells were both validated by reverse transcription-quantitative PCR. The results suggested that, as an emerging RBP, FDPS may serve an important role in transcriptome profiles by altering gene expression and regulating AS. FDPS also affected the cell proliferation rate. These findings broaden the understanding of the molecular functions of FDPS, and the potential of FDPS as a target in therapy should be investigated.

Effect of simvastatin on osteogenesis of the extremity bones in aging rats

PURPOSE

Simvastatin is a prodrug of the potent 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor. The main purpose of the current study is to assess the accurate function of simvastatin on osteoporosis of extremity bones in aging rats.

MATERIALS AND METHODS

Fifty 15-month-old SD rats were divided into five groups (four simvastatin groups and one control group). The rats in four simvastatin groups were fed with different doses of simvastatin (5, 10, 20, and 40 mg/kg/d, respectively) for 3 months, whereas the rats in control group were fed the equal physiological saline. Calcium (Ca), phosphorus (P), and the lipid spectrum in serum were measured. Biochemical markers of bone metabolism, osteocalcin (OC), and tartrate-resistant acid phosphatase (Trap-5b), were analyzed using ELISA. The content of adipocytes in bone marrow was analyzed by histological staining. Finally, the bone quality of the femur and tibia were evaluated using dual-energy X-ray absorptiometry (DEXA), peri-quantity CT (pQCT), and the 3-point bending biomechanical test.

RESULTS

Simvastatin reduced serum triglycerides (TG), and 10 mg/kg/d of simvastatin significantly reduced the content of adipocytes in bone marrow compared to the control group. However, statistically significant differences between the simvastatin groups and the control group were not found in the CA, P, OC, Trap-5b, or the evaluation indexes of bone quality from DEXA, pQCT, and biomechanical tests.

CONCLUSION

Simvastatin could not prevent osteoporosis of the extremity bones in aging rats.

Molecular targets of statins and their potential side effects: Not all the glitter is gold

Statins are a class of drugs widely used worldwide to manage hypercholesterolemia and the prevention of secondary heart attacks. Currently, available statins vary in terms of their pharmacokinetic and pharmacodynamic profiles. Although the primary target of statins is the inhibition of HMG-CoA reductase (HMGR), the rate-limiting enzyme in cholesterol biosynthesis, statins exhibit many pleiotropic effects downstream of the mevalonate pathway. These pleiotropic effects include the ability to reduce myocardial fibrosis, pathologic cardiac disease states, hypertension, promote bone differentiation, anti-inflammatory, and antitumor effects through multiple mechanisms. Although these pleiotropic effects of statins may be a cause for enthusiasm, there are many adverse effects that, for the most part, are unappreciated and need to be highlighted. These adverse effects include myopathy, new-onset type 2 diabetes, renal and hepatic dysfunction. Although these adverse effects may be relatively uncommon, considering the number of people worldwide who use statins daily, the actual number of people affected becomes quite large. Also, co-administration of statins with several other medications, herbal agents, and foods, which interact through common enzymatic pathways, can have untoward clinical consequences. In this review, we address these concerns.

The associations of statin intake and the trabecular bone score and bone mineral density status in elderly Iranian individuals: a cross-sectional analysis of the Bushehr Elderly Health (BEH) program

In recent years, a growing interest on the impact of statin intake on bone health has emerged, although the reported results are controversial. The results of this study revealed that BMD at lumbar spine has a significant association with statin intake. However, such association appears to be weaker regarding TBS values compared to BMD. This study was performed with the aim of evaluating associations of statin intake with BMD and TBS using data from 2426 individuals aged ≥ 60 years from the second phase of the Bushehr Elderly Health (BEH) program. We found a positive association between statin and BMD at lumbar spine, whereas association between statin and TBS was detected only in the men in the final model.

INTRODUCTION

In recent years, a growing interest has been established to evaluate the impact of statin intake on bone health, although the reported results are controversial. This study aimed to evaluate the association of statin intake with bone health status according to BMD and TBS.

METHODS

This cross-sectional analysis used data from the elderly Iranian individuals who participated in the Bushehr Elderly Health (BEH) program. Dual x-ray absorptiometry (DXA) device was used to evaluate the BMD at lumbar spine (L1-L4), femoral neck, and total hip, as well as TBS at lumbar spine.

RESULTS

Among 2426 (1260 women and 1166 men) study participants, 778 were statin users. A positive significant association, irrespective of sex, was observed between statin intake and BMD at L1-L4, even after controlling for potential variables in total population (β = 0.016, p = 0.013). The mean TBS values at L1-L4 were negatively associated with statin intake in total population (β =  - 0.009, p = 0.001), while in the full adjusted model, significant positive association between TBS and statin intake was detected only in men (β = 0.013, p = 0.02).

CONCLUSION

The results of this study revealed that BMD at lumbar spine has a significant association with statin intake. However, such an association appears to be weaker regarding TBS values compared to BMD.

The role of statins in the differentiation and function of bone cells

BACKGROUND

Statins are 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors blocking cholesterol biosynthesis in hepatic cells, thereby causing an increase in low-density lipoprotein (LDL) receptors resulting in enhanced uptake and clearance of atherogenic LDL-cholesterol (LDL-C) from the blood. Accordingly, statins decrease the risk of developing atherosclerosis and its acute complications, such as acute myocardial infarction and ischaemic stroke. Besides the LDL-C-lowering impact, statins also have other so-called pleiotropic effects. Among them, the ability to modulate differentiation and function of bone cells and exert direct effects on osteosynthesis factors. Specifically, earlier studies have shown that statins cause in vitro and in vivo osteogenic differentiation.

DESIGN

The most relevant papers on the bone-related 'pleiotropic' effects of statins were selected following literature search in databases and were reveiwed.

RESULTS

Statins increase the expression of many mediators involved in bone metabolism including bone morphogenetic protein-2 (BMP-2), glucocorticoids, transforming growth factor-beta (TGF-β), alkaline phosphatase (ALP), type I collagen and collagenase-1. As a result, they enhance bone formation and improve bone mineral density by modulating osteoblast and osteoclast differentiation.

CONCLUSION

This review summarizes the literature exploring bone-related 'pleiotropic' effects of statins and suggests an anabolic role in the bone tissue for this drug class. Accordingly, current knowledge encourages further clinical trials to assess the therapeutic potential of statins in the treatment of bone disorders, such as arthritis and osteoporosis.

Cyclodextrin-Based Supramolecular Complexes of Osteoinductive Agents for Dental Tissue Regeneration

Oral tissue regeneration has received growing attention for improving the quality of life of patients. Regeneration of oral tissues such as alveolar bone and widely defected bone has been extensively investigated, including regenerative treatment of oral tissues using therapeutic cells and growth factors. Additionally, small-molecule drugs that promote bone formation have been identified and tested as new regenerative treatment. However, treatments need to progress to realize successful regeneration of oral functions. In this review, we describe recent progress in development of regenerative treatment of oral tissues. In particular, we focus on cyclodextrin (CD)-based pharmaceutics and polyelectrolyte complexation of growth factors to enhance their solubility, stability, and bioactivity. CDs can encapsulate hydrophobic small-molecule drugs into their cavities, resulting in inclusion complexes. The inclusion complexation of osteoinductive small-molecule drugs improves solubility of the drugs in aqueous solutions and increases in vitro osteogenic differentiation efficiency. Additionally, various anionic polymers such as heparin and its mimetic polymers have been developed to improve stability and bioactivity of growth factors. These polymers protect growth factors from deactivation and degradation by complex formation through electrostatic interaction, leading to potentiation of bone formation ability. These approaches using an inclusion complex and polyelectrolyte complexes have great potential in the regeneration of oral tissues.

Re-appraising the potential of naringin for natural, novel orthopedic biotherapies

Naringin is a naturally occurring flavonoid found in plants of the Citrus genus that has historically been used in traditional Chinese medical regimens for the treatment of osteoporosis. Naringin modulates signaling through numerous molecular pathways critical to musculoskeletal development, cellular differentiation, and inflammation. Administration of naringin increases in vitro expression of bone morphogenetic proteins (BMPs) and activation of the Wnt/β-catenin and extracellular signal-related kinase (Erk) pathways, thereby promoting osteoblastic proliferation and differentiation from stem cell precursors for bone formation. Naringin also inhibits osteoclastogenesis by both modifying RANK/RANKL interactions and inducing apoptosis in osteoclasts in vitro. In addition, naringin acts on the estrogen receptor in bone to mimic the native bone-preserving effects of estrogen, with few systemic side effects on other estrogen-sensitive tissues. The efficacy of naringin therapy in reducing the osteolysis characteristic of common musculoskeletal pathologies such as osteoporosis, degenerative joint disease, and osteomyelitis, as well as inflammatory conditions affecting bone such as diabetes mellitus, has been extensively demonstrated in vitro and in animal models. Naringin thus represents a naturally abundant, cost-efficient agent whose potential for use in novel musculoskeletal biotherapies warrants re-visiting and further exploration through human studies. Here, we review the cellular mechanisms of action that have been elucidated regarding the action of naringin on bone resident cells and the bone microenvironment, in vivo evidence of naringin’s osteostimulative and chondroprotective properties in the setting of osteolytic bone disease, and current limitations in the development of naringin-containing translational therapies for common musculoskeletal conditions.

Water/pH dual responsive in situ calcium supplement collaborates simvastatin for osteoblast promotion mediated osteoporosis therapy via oral medication

Calcium supplement is the most commonly adopted treatment for osteoporosis but usually requires high dose and frequency. The modality of calcium supplement is therefore overlooked by current nanomedicine-based osteoporosis therapies without proper oral formulations. Herein, we proposed a tetracycline (Tc) modified and monostearin (MS) coated amorphous calcium carbonate (ACC) platform (TMA) as oral bone targeted and osteoporosis microenvironment (water/pH) responsive carrier for in situ calcium supplement. Moreover, current osteoporosis therapies also fall short of finding suitable molecular target and effective therapeutic regimen to further increase the therapeutic efficacy over available treatment means. As a result, the simvastatin (Sim) was loaded into TMA to construct drug delivery system (TMA/Sim) capable of synergistically activating the bone morphogenetic proteins (BMPs)-Smad pathway to provide a novel therapeutic regimen for osteoblast promotion mediated osteoporosis therapy. Our results revealed that optimized TMA showed high accessibility and oral availability with targeted drug delivery to bone tissue. Most importantly, benefit from the effective in situ calcium supplement and targeted Sim delivery, this therapeutic regime (TMA/Sim) achieved better synergetic effects than conventional combination strategies with promising osteoporosis reversion performance under low calcium dosage (1/10 of commercial calcium carbonate tablet) and significantly attenuated side effects.

Response surface optimization of biocompatible elastic nanovesicles loaded with rosuvastatin calcium: enhanced bioavailability and anticancer efficacy

Statins are mainly used for the treatment of hyperlipidemia, but recently, their anticancer role was extremely investigated. The goal of this study was to statistically optimize novel elastic nanovesicles containing rosuvastatin calcium to improve its transdermal permeability, bioavailability, and anticancer effect. The elastic nanovesicles were composed of Tween® 80, cetyl alcohol, and clove oil. The nanodispersions were investigated for their entrapment efficiency, particle size, zeta potential, polydispersity index, and elasticity. The optimized elastic nanovesicular dispersion is composed of 20% cetyl alcohol, 53.47% Tween 80, and 26.53% clove oil. Carboxy methylcellulose was utilized to convert the optimized elastic nanovesicular dispersion into elastic nanovesicular gels. Both the optimized dispersion and the optimized gel (containing 2% w/v carboxymethylcellulose) were subjected to in vitro release study, scanning and transmission electron microscopy, histopathological evaluation, and ex vivo permeation. The cell viability assay of the optimized gel on MCF-7 and Hela cell lines showed significant antiproliferative and potent cytotoxic effects when compared to the drug gel. Moreover, the optimized gel accomplished a significant increase in rosuvastatin bioavailability upon comparison with the drug gel. The optimized gel could be considered as a promising nanocarrier for statins transdermal delivery to increase their systemic bioavailability and anticancer effect. Graphical abstract.

Drug Delivery Systems Based on Titania Nanotubes and Active Agents for Enhanced Osseointegration of Bone Implants

TiO2 nanotubes (TNTs) are attractive nanostructures for localized drug delivery. Owing to their excellent biocompatibility and physicochemical properties, numerous functionalizations of TNTs have been attempted for their use as therapeutic agent delivery platforms. In this review, we discuss the current advances in the applications of TNT-based delivery systems with an emphasis on the various functionalizations of TNTs for enhancing osteogenesis at the bone-implant interface and for preventing implant-related infection. Innovation of therapies for enhancing osteogenesis still represents a critical challenge in regeneration of bone defects. The overall concept focuses on the use of osteoconductive materials in combination with the use of osteoinductive or osteopromotive factors. In this context, we highlight the strategies for improving the functionality of TNTs, using five classes of bioactive agents: growth factors (GFs), statins, plant derived molecules, inorganic therapeutic ions/nanoparticles (NPs) and antimicrobial compounds.

No Bones About It: Small Molecules for Bone Regeneration

In this issue of Cell Chemical Biology, Cook et al. (2019) report a new small-molecule activator that enhances osteogenesis and skeletal regeneration in developmental and adult animal models, respectively. This discovery has therapeutic potential for healing following traumatic bone injury, as well as bone remodeling in response to osteoporosis.

Annatto-Derived Tocotrienol Promotes Mineralization of MC3T3-E1 Cells by Enhancing BMP-2 Protein Expression via Inhibiting RhoA Activation and HMG-CoA Reductase Gene Expression

PURPOSE

Annatto-derived tocotrienol (AnTT) has been shown to improve bone formation in animal models of osteoporosis and promote differentiation of pre-osteoblastic cells. However, the mechanism of action of AnTT in achieving these effects is unclear. This study aims to investigate the mechanism of action of AnTT on MC3T3-E1 pre-osteoblasts via the mevalonate pathway.

METHODS

Murine pre-osteoblastic cells, MC3T3-E1, were cultured with the density of 1 × 104 cells/mL and treated with 4 concentrations of AnTT (0.001-1 µg/mL). Expression of HMG-CoA reductase (HMGR) gene was carried out using qPCR after treatment with AnTT for 21 days. RhoA activation and bone morphogenetic protein-2 (BMP-2) were measured using immunoassay after 9 and 15 days of AnTT treatment. Lovastatin was used as the positive control. Mineralized nodules were detected using Von Kossa staining after 21 days of AnTT treatment.

RESULTS

The results showed that HMGR was up-regulated in the lovastatin group on day 9 and 21 compared to the control. Lovastatin also inhibited RhoA activation (day 9 and 15) and increased BMP-2 protein (day 15). On the other hand, AnTT at 0.001 μg/mL (day 3) and 0.1 μg/mL (day 21) significantly down-regulated HMGR gene expression compared to the control. On day 21, HMGR gene expression was significantly reduced in all groups compared to day 15. AnTT at 0.1 μg/mL significantly decreased RhoA activation on day 9 compared to the control. AnTT at 1 μg/mL significantly increased BMP-2 protein on day 15 compared to the control (P<0.05). Mineralized calcium nodules were more abundant in AnTT treated groups compared to the control on day 21.

CONCLUSION

AnTT suppresses the mevalonate pathway by downregulating HMGR gene expression and inhibiting RhoA activation, leading to increased BMP-2 protein in MC3T3-E1 cells. This explains the stimulating effects of AnTT on osteoblast mineralization.

Design and in vitro/in vivo evaluations of a multiple-drug-containing gingiva disc for periodontotherapy

In the current work, we set out to develop and evaluate a gingiva disc of cellulose acetate phthalate and poloxamer F-127 for the simultaneous delivery of multiple drugs, namely minocycline, celecoxib, doxycycline hyclate, and simvastatin, to abolish infection, impede inflammation, avert collagen destruction, and promote alveolar bone regeneration, respectively. In vitro release studies revealed the sustained release profiles of the drugs for 12 h and that they were active against Staphylococcus aureus, Escherichia coli and Streptococcus mutans. The in vivo bioactivity levels of these drugs were assessed by comparing the number of colony forming units during different phases of a study on Wistar rats, and the results showed a reduction in the number of bacterial colonies with the applied formulation. A mucosal irritation study conducted on Wistar rat gingiva confirmed the non-irritancy of the optimal gingiva disc. Hence, this customized, non-invasive polymeric gingiva disc displaying a sustained release of drugs can be a useful tool to treat acute to moderate stages of periodontitis.

Diagnosis of osteoporosis in statin-treated patients is dose-dependent

OBJECTIVE

Whether HMG-CoA-reductase inhibition, the main mechanism of statins, plays a role in the pathogenesis of osteoporosis, is not entirely known so far. Consequently, this study was set out to investigate the relationship of different kinds and dosages of statins with osteoporosis, hypothesising that the inhibition of the synthesis of cholesterol could influence sex-hormones and therefore the diagnosis of osteoporosis.

METHODS

Medical claims data of all Austrians from 2006 to 2007 was used to identify all patients treated with statins to compute their daily defined dose averages of six different types of statins. We applied multiple logistic regression to analyse the dose-dependent risks of being diagnosed with osteoporosis for each statin individually.

RESULTS

In the general study population, statin treatment was associated with an overrepresentation of diagnosed osteoporosis compared with controls (OR: 3.62, 95% CI 3.55 to 3.69, p<0.01). There was a highly non-trivial dependence of statin dosage with the ORs of osteoporosis. Osteoporosis was underrepresented in low-dose statin treatment (0-10 mg per day), including lovastatin (OR: 0.39, CI 0.18 to 0.84, p<0.05), pravastatin (OR: 0.68, 95% CI 0.52 to 0.89, p<0.01), simvastatin (OR: 0.70, 95% CI 0.56 to 0.86, p<0.01) and rosuvastatin (OR: 0.69, 95% CI 0.55 to 0.87, p<0.01). However, the exceeding of the 40 mg threshold for simvastatin (OR: 1.64, 95% CI 1.31 to 2.07, p<0.01), and the exceeding of a 20 mg threshold for atorvastatin (OR: 1.78, 95% CI 1.41 to 2.23, p<0.01) and for rosuvastatin (OR: 2.04, 95% CI 1.31 to 3.18, p<0.01) was related to an overrepresentation of osteoporosis.

CONCLUSION

Our results show that the diagnosis of osteoporosis in statin-treated patients is dose-dependent. Thus, osteoporosis is underrepresented in low-dose and overrepresented in high-dose statin treatment, demonstrating the importance of future studies' taking dose-dependency into account when investigating the relationship between statins and osteoporosis.

The stimulatory impact of d-δ-Tocotrienol on the differentiation of murine MC3T3-E1 preosteoblasts

Osteoblasts and osteoclasts play essential and opposite roles in maintaining bone homeostasis. Osteoblasts fill cavities excavated by osteoclasts. The mevalonate pathway provides essential prenyl pyrophosphates for the activities of GTPases that promote differentiation of osteoclasts but suppress that of osteoblasts. Preclinical and clinical studies suggest that mevalonate suppressors such as statins increase bone mineral density and reduce risk of bone fracture. Tocotrienols down-regulate 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, the rate-limiting enzyme in the mevalonate pathway. In vivo studies have shown the bone-protective activity of tocotrienols. We hypothesize that d-δ-tocotrienol, a mevalonate suppressor, induces differentiation of murine MC3T3-E1 preosteoblasts. Alizarin staining showed that d-δ-tocotrienol (0-25 μmol/L) induced mineralized nodule formation in a concentration-dependent manner in MC3T3-E1 preosteoblasts. d-δ-Tocotrienol (0-25 μmol/L), but not D-α-tocopherol (25 μmol/L), significantly induced alkaline phosphatase activity, an indicator of preosteoblast differentiation. The expression of differentiation marker genes including BMP-2 and VEGFα was stimulated dose dependently by d-δ-tocotrienol (0-25 μmol/L). Concomitantly, Western blot analysis showed that d-δ-tocotrienol down-regulated HMG CoA reductase. d-δ-Tocotrienol (0-25 μmol/L) had no impact on the viability of MC3T3-E1 preosteoblasts following 48-h incubation, suggesting lack of cytotoxicity at these doses. Tocotrienols and other mevalonate suppressors have potential in maintaining bone health.

Alpha-5 Integrin Mediates Simvastatin-Induced Osteogenesis of Bone Marrow Mesenchymal Stem Cells

Simvastatin (SVS) promotes the osteogenic differentiation of mesenchymal stem cells (MSCs) and has been studied for MSC-based bone regeneration. However, the mechanism underlying SVS-induced osteogenesis is not well understood. We hypothesize that α5 integrin mediates SVS-induced osteogenic differentiation. Bone marrow MSCs (BMSCs) derived from BALB/C mice, referred to as D1 cells, were used. Alizarin red S (calcium deposition) and alkaline phosphatase (ALP) staining were used to evaluate SVS-induced osteogenesis of D1 cells. The mRNA expression levels of α5 integrin and osteogenic marker genes (bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), collagen type I, ALP and osteocalcin (OC)) were detected using quantitative real-time PCR. Surface-expressed α5 integrin was detected using flow cytometry analysis. Protein expression levels of α5 integrin and phosphorylated focal adhesion kinase (p-FAK), which is downstream of α5 integrin, were detected using Western blotting. siRNA was used to deplete the expression of α5 integrin in D1 cells. The results showed that SVS dose-dependently enhanced the gene expression levels of osteogenic marker genes as well as subsequent ALP activity and calcium deposition in D1 cells. Upregulated p-FAK was accompanied by an increased protein expression level of α5 integrin after SVS treatment. Surface-expressed α5 integrin was also upregulated after SVS treatment. Depletion of α5 integrin expression significantly suppressed SVS-induced osteogenic gene expression levels, ALP activity, and calcium deposition in D1 cells. These results identify a critical role of α5 integrin in SVS-induced osteogenic differentiation of BMSCs, which may suggest a therapeutic strategy to modulate α5 integrin/FAK signaling to promote MSC-based bone regeneration.

Graphene Family Materials in Bone Tissue Regeneration: Perspectives and Challenges

We have witnessed abundant breakthroughs in research on the bio-applications of graphene family materials in current years. Owing to their nanoscale size, large specific surface area, photoluminescence properties, and antibacterial activity, graphene family materials possess huge potential for bone tissue engineering, drug/gene delivery, and biological sensing/imaging applications. In this review, we retrospect recent progress and achievements in graphene research, as well as critically analyze and discuss the bio-safety and feasibility of various biomedical applications of graphene family materials for bone tissue regeneration.

Effect of local administration of simvastatin on postorthodontic relapse in a rabbit model

INTRODUCTION

Posttreatment relapse is a major challenging clinical issue. The objective of this study was to evaluate the effect of local administration of simvastatin on posttreatment relapse.

METHODS

Orthodontic tooth movement was induced in 10 white New Zealand rabbits. After 21 days of active tooth movement, the orthodontic appliances were removed, and the experimental teeth were allowed to relapse for 21 days. During the relapse phase, 1 mandibular quadrant received local simvastatin administration, and the other received the control vehicle solution on a weekly basis. Three-dimensional models of the experimental teeth were created to allow the measurement of experimental tooth movement and posttreatment relapse. The animals were killed at the end of the relapse phase for histomorphometric analysis of alveolar bone remodeling.

RESULTS

The mean relapse percentages were 75.83% in the quadrant receiving the control vehicle solution and 62.01% in the quadrant receiving simvastatin. Neither the relapse magnitude nor the relapse percentage showed a significant difference between the 2 quadrants. Histomorphometric analyses showed that local simvastatin administration yielded a significant reduction in the area of active bone-resorptive lacunae and a significant increase in newly formed bone area.

CONCLUSIONS

Although local administration of simvastatin aids in bone remodeling associated with posttreatment relapse by reducing the area of active bone resorption and upregulating bone formation, it did not significantly minimize posttreatment relapse.

Bone Morphogenetic Protein-Based Therapeutic Approaches

Bone morphogenetic proteins (BMPs) constitute the largest subdivision of the transforming growth factor (TGF)-β family of ligands and exert most of their effects through the canonical effectors Smad1, 5, and 8. Appropriate regulation of BMP signaling is critical for the development and homeostasis of numerous human organ systems. Aberrations in BMP pathways or their regulation are increasingly associated with diverse human pathologies, and there is an urgent and growing need to develop effective approaches to modulate BMP signaling in the clinic. In this review, we provide a wide perspective on diseases and/or conditions associated with dysregulated BMP signal transduction, outline the current strategies available to modulate BMP pathways, highlight emerging second-generation technologies, and postulate prospective avenues for future investigation.

Maxillary sinus lift using osteoinductive simvastatin combined with β-TCP versus β-TCP - a comparative pilot study to evaluate simvastatin enhanced and accelerated bone formation

PURPOSE

The aim of this study was to evaluate available bone quality and quantity after performing sinus augmentation using simvastatin/β-TCP combination versus β-TCP alone.

MATERIALS AND METHODS

This study included eight sinus lift procedures conducted on six patients. The sinuses were divided into two equal groups. The patients were recalled one, two weeks two, five, nine months post-operatively for post-operative evaluation. Radiographic evaluation involved cone beam computed tomography (CBCT) radiographs taken for every patient one week and nine months post-operatively to evaluate the changes in bone height, while histomorphometric evaluation involved transcortical bone biopsies taken after nine months during the second-stage surgery for implant placement.

RESULTS

The histomorphometric results showed that the amount of newly formed bone was higher in the simvastatin group when compared to the β-TCP group nine months after the surgery; the difference between the two groups was statistically significant. On the other hand, the radiographic evaluation showed that the rate of resorption of the simvastatin group was found to be higher than the control group; however, the difference between both groups was statistically insignificant.

CONCLUSION

These results showed that Simvastatin is safe to be used in sinus lift with promising osteoinductive capacity, yet further studies using larger sample size is needed.

Hydroxychloroquine decreases human MSC-derived osteoblast differentiation and mineralization in vitro

We recently showed that patients with primary Sjögren Syndrome (pSS) have significantly higher bone mineral density (BMD) compared to healthy controls. The majority of those patients (69%) was using hydroxychloroquine (HCQ), which may have favourable effects on BMD. To study the direct effects of HCQ on human MSC‐derived osteoblast activity. Osteoblasts were cultured from human mesenchymal stromal cells (hMSCs). Cultures were treated with different HCQ doses (control, 1 and 5 µg/ml). Alkaline phosphatase activity and calcium measurements were performed to evaluate osteoblast differentiation and activity, respectively. Detailed microarray analysis was performed in 5 µg/ml HCQ‐treated cells and controls followed by qPCR validation. Additional cultures were performed using the cholesterol synthesis inhibitor simvastatin (SIM) to evaluate a potential mechanism of action. We showed that HCQ inhibits both MSC‐derived osteoblast differentiation and mineralization in vitro. Microarray analysis and additional PCR validation revealed a highly significant up‐regulation of the cholesterol biosynthesis, lysosomal and extracellular matrix pathways in the 5 µg/ml HCQ‐treated cells compared to controls. Besides, we demonstrated that 1 µM SIM also decreases MSC‐derived osteoblast differentiation and mineralization compared to controls. It appears that the positive effect of HCQ on BMD cannot be explained by a stimulating effect on the MSC‐derived osteoblast. The discrepancy between high BMD and decreased MSC‐derived osteoblast function due to HCQ treatment might be caused by systemic factors that stimulate bone formation and/or local factors that reduce bone resorption, which is lacking in cell cultures.

Locally Applied Simvastatin Promotes Bone Formation in a Rat Model of Spinal Fusion

Simvastatin, an inexpensive lipid-lowering drug widely used to prevent cardiovascular disorders, is known to increase osteoblastic activity, inhibit osteoclastic activity, and stimulate osteoblastic production of bone morphogenetic protein 2. Furthermore, local simvastatin application increased bone formation in animal models of fracture or bone defects. We investigated the effect of locally applied simvastatin in a rat model of spinal fusion. We performed posterolateral lumbar fusion surgery with iliac crest autograft in 36 rats divided into group I (n = 17; implanted with a gelatin scaffold) and group II (n = 19; implanted with a gelatin scaffold infused with 0.5 mg simvastatin). The rats were euthanized at 6 or 12 weeks postoperatively, and the spines were explanted and assessed. The fusion rates in group II (16.7%: 6 weeks, 30%: 12 weeks) were considerably higher than those in groups I (0%: 6 weeks, 0%: 12 weeks). The 6- and 12-week radiographic scores were significantly higher in group II than in group I. High-resolution micro-computerized tomography revealed that the tissue and bone volumes of the callus tended to be higher in group II than in group I. Histologic analysis of the spines explanted after 12 weeks demonstrated new bone formation between the transverse processes in group II, but thicker and wider individual trabeculae with fibrotic tissue and muscle fiber between the transverse processes in group I. Locally applied simvastatin was efficacious in accelerating bone formation in our rat model of spinal fusion, supporting its potential clinical application as a promoter of bone morphogenesis in spinal fusion. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1942-1948, 2017.

Microparticle-embedded fibroin/alginate beads for prolonged local release of simvastatin hydroxyacid to mesenchymal stem cells

In the present work, we propose silk fibroin/alginate (SF/Alg) beads embedding simvastatin-loaded biodegradable microparticles as a versatile platform capable of tuning SVA release and in so doing osteogenic effects. In a first part of the study, microparticles of poly(lactic-co-glycolic) acid incorporating simvastatin either as lactone (SVL) or as hydroxyacid form (SVA) were prepared by spray-drying. While SVA-loaded microparticles released the drug in three days, long-term release of SVA could be obtained from SVL-loaded microparticles. In this latter case, SVL was promptly transformed to the osteogenic active SVA during release. When tested on mesenchymal stem cells, a time- and dose-dependent effect of SVL-loaded microparticles on cell proliferation and alkaline phosphatase (ALP) activity was found. Thereafter, SVL-loaded microparticles were embedded in SF/Alg beads to limit the initial simvastatin burst and to achieve easier implantation as well. Microparticle-embedded beads showed no cytotoxicity while ALP activity increased. If correctly exploited, the developed system may be suitable as osteogenic polymer scaffolds releasing correct amount of the drug locally for long time-frames.

Effect of in-situ application of simvastatin gel in surgical management of osseous defects in chronic periodontitis-A randomized clinical trial

BACKGROUND

The present randomized controlled clinical study was designed to investigate the effect of in situ application of 1.2 mg Simvastatin (SV) gel in the surgical management of Intrabony defects in chronic periodontitis patients.

METHODOLOGY

20 patients contributing 40 sites were categorized into two treatment groups: Open flap debridement plus 1.2 mg SV gel (Group 1) and Open flap debridement plus Placebo gel (Group 2). Gingival index (GI), Plaque index (PI), Pocket depth (PD) and clinical attachment level (CAL) were recorded at baseline, 3 months, 6 months and 9 months. At baseline and at the end of 6 and 9 months Radiographic evaluation of Intrabony defect fill was done using Image j software.

RESULTS

Significant reduction of GI, PD and gain in CAL was observed at the end of 9 months in both groups. Amount of bone fill and percentage of original defect fill in Group 1 was statistically highly significant than Group 2 at the end of 6 and 9 months.

CONCLUSION

Higher amount of decrease in GI and PD along with more amount of CAL gain was observed in treatment group than control group. Radiological assessment confirmed that significant intrabony defect fill and percentage fill of original defect in treatment group than controlled group.

Healing of extraction socket following local application of simvastatin: A split mouth prospective study

BACKGROUND

The role of simvastatin in lowering serum cholesterol level is well described. However, recent findings suggest they have a role in bone formation as well.

AIM AND OBJECTIVES

The present prospective study was conducted to evaluate the efficacy of simvastatin on bone formation in extraction sockets.

MATERIALS AND METHODS

15 patients undergoing all four first premolar extraction were selected based on inclusion and exclusion criteria. Extraction sockets of left premolars (24 and 34) were considered as cases and right premolars (14 and 44) as controls. Overall 30 extraction sites were assigned to each group. Atraumatic extraction was done in all cases following which simvastatin mixed with gelatin sponge was placed in extraction socket of 24 and 34 while only gelatin sponge was placed in 14 and 44. All sockets were then closed with 3-0 vicryl. The patients were kept on follow-up and complications such as dry socket, pain, and swelling were recorded. Intra oral peri apical radiographs were taken immediately after extraction and at 2nd month and 4th month to record changes in the density of alveolar bone. The radiographic measurements were compared and the differences were statistically analyzed.

RESULT

Percent increase in bone density at the end of 8th week and 16th week was significantly high in case as compared to the control group.

CONCLUSION

Local application of simvastatin induces bone formation in extraction sockets. Application is very simple and provides a very cost effective way of faster bone regeneration following tooth extraction.

Thermoreversible in situ gel for subgingival delivery of simvastatin for treatment of periodontal disease

OBJECTIVE

The aim of this in vitro study was to formulate an in situ thermoreversible injectable gel with poloxamer (PM) and methylcellulose (MC) to deliver simvastatin (SMV) in a controlled manner.

SUBJECTS AND METHODS

Preformulation studies (Fourier transform infrared and differential scanning calorimetry) to assess the interaction between SMV and MC and PM were performed before gel formulation. Keeping the concentration of SMV at 2.2%, the concentration of PM and MC was altered to formulate in situ thermosensitive gel at 37°C. Rheological studies were carried to analyze the physical property of the various formulations. Drug release profile and stability studies were done for the selected formulation. The in vitro drug release profile was carried out for using open end tube method and ultraviolet spectroscopy.

RESULTS

The preformulation studies showed that there is no interaction between the polymer and drug based on the rheological studies of different formulation, the formulation. F8 gels at 37°C and attains a viscosity of 4150 cps.

CONCLUSIONS

PM 25% and MC 5% formed an ideal thermosensitive injectable gel at 37°C for subgingival delivery of SMV and also show controlled drug release for the period of 10 days in vitro.

Effect of simvastatin on osteogenesis of the lumbar vertebrae in ovariectomized rats

The aim of the present study was to assess the role of simvastatin on osteoporosis of the vertebrae by examining the effect of simvastatin on the osteogenesis of the lumbar vertebra in ovariectomized (OVX) rats. A total of 60 6-month-old female Sprague Dawley rats were divided into one sham group and five ovariectomized groups, consisting of four simvastatin groups and one control group. Four dosages of simvastatin (5, 10, 20 and 40 mg/kg/d) were administered by gavage for three months. L4 vertebrae were examined by dual-energy X-ray absorptiometry (DEXA) and peripheral quantitative computed tomography (pQCT) to determine the mineral apposition rate (MAR). L5 vertebrae were examined using a compression biomechanical test. Although the measurements from DEXA, pQCT and MAR, and the biomechanical parameters in the OVX + simvastatin rats were higher than those for the OVX + vehicle group, no significant differences were detected. Therefore, simvastatin may not improve osteogenesis of the lumbar vertebra in OVX rats or prevent osteoporosis of the spinal vertebrae.

Multiple drilling combined with simvastatin versus multiple drilling alone for the treatment of avascular osteonecrosis of the femoral head: 3-year follow-up study

Background

Multiple small drilling for core decompression is widely used to preserve the femoral head in patients with avascular necrosis of the femoral head (ANFH). Nevertheless, the clinical outcome remains controversial. Simvastatin has been demonstrated to promote bone formation and reduce bone adsorption. The purpose of this study was to determine whether simvastatin enhanced the effect of multiple decompressions in preventing progression of ANFH and to identify independent risk factors associated with poor results.

Methods

We retrospectively analyzed 58 hips in 36 patients, with a follow-up of 36 months. 20 patients (32 hips) underwent multiple drilling combined with simvastatin treatment (SIM group); 16 patients (26 hips) underwent multiple drilling alone (MD group). We defined clinical failure as a requirement for subsequent hip surgery or Harris Hip Score < 75. New occurrence of collapse or increased collapse > 2 mm on plain radiographs was defined as radiological failure.

Results

Successful clinical results were achieved in 27 of 32 hips (84 %) in the SIM group compared with 15 of 26 hips (58 %) in the MD group (OR = 0.2, CI (0.1, 0.6.), P = 0.032). Successful radiological results were achieved in 27 of 32 hips (84 %) in the SIM group and in 16 of 26 hips (61.5 %) in the MD group (P = 0.048). Body mass index, disease stage and location of lesion were independent prognostic factors for overall survival.

Conclusions

We believe that simvastatin could enhance the effects of multiple decompressions in preventing progression of ANFH and reducing the risk of femoral head collapse.

A Survey of Strategies to Modulate the Bone Morphogenetic Protein Signaling Pathway: Current and Future Perspectives

Bone morphogenetic proteins (BMPs) constitute the largest subdivision of the TGF-β family of ligands and are unequivocally involved in regulating stem cell behavior. Appropriate regulation of canonical BMP signaling is critical for the development and homeostasis of numerous human organ systems, as aberrations in the BMP pathway or its regulation are increasingly associated with diverse human pathologies. In this review, we provide a wide-perspective on strategies that increase or decrease BMP signaling. We briefly outline the current FDA-approved approaches, highlight emerging next-generation technologies, and postulate prospective avenues for future investigation. We also detail how activating other pathways may indirectly modulate BMP signaling, with a particular emphasis on the relationship between the BMP and Activin/TGF-β pathways.

Effect of treatment with simvastatin on bone microarchitecture of the femoral head in an osteoporosis animal model

The objective of this study was to evaluate the microarchitecture and trabecular bone strength at the distal region of the femur, and its biomechanical properties with simvastatin administration with two different doses in ovariectomized (OVX) rats. Ninety rats were divided into six groups to evaluate treatment with the simvastatin drug (n = 15): SH (Sham surgery), SH-5 (5 mg simvastatin), SH-20 (20 mg simvastatin), OVX, OVX-5, and OVX-20. Euthanasia was performed at three different times, five animals per period: 7, 14, and 28 days. The effectiveness of the treatments was evaluated by mechanical testing and histomorphometric analysis of the femurs. The results of analysis by the linear model of mixed effects showed 20 mg of simvastatin results in increased trabecular bone after 14 days (P = 0.039) of ingestion in ovariectomized animals. However, ingestion of 5 mg of simvastatin is able to sensitize the trabecular bone only at 28 days (P = 0.005) of ingestion. In the mechanical tests stiffness improves within 28 days (P = 0.003). Regarding maximum strength, no statistical differences were observed. According to these results, it can be concluded that for a decrease in oral intake, longer treatment times are required. Microsc. Res. Tech. 79:684-690, 2016. © 2016 Wiley Periodicals, Inc.

Simvastatin rescues homocysteine-induced apoptosis of osteocytic MLO-Y4 cells by decreasing the expressions of NADPH oxidase 1 and 2

Clinical studies have shown that hyperhomocysteinemia is associated with bone fragility. Homocysteine (Hcy) induces apoptosis of osteoblastic cell lineage by increasing oxidative stress, which may contribute to Hcy-induced bone fragility. Statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, ameliorate oxidative stress by regulating oxidant and anti-oxidant enzymes. However, the effects of statins on Hcy-induced apoptosis of osteocytes are unknown. This study was thus aimed to investigate whether or not statins prevent Hcy-induced apoptosis of osteocytic MLO-Y4 cells and regulate NADPH oxidase (Nox) expression. TUNEL staining showed that 5 mM Hcy induced apoptosis of MLO-Y4 cells, and that co-incubation of 10(-9) or 10(-8) M simvastatin significantly suppressed the apoptotic effect. Moreover, we confirmed the beneficial effect of simvastatin against Hcy's apoptotic effect by using a DNA fragment ELISA assay. However, TUNEL staining showed no significant effects of pravastatin, a hydrophilic statin, on the Hcy-induced apoptosis. Real-time PCR showed that Hcy increased the mRNA expressions of Nox1 and Nox2, whereas simvastatin inhibited the stimulation of Nox1 and Nox2 expressions by Hcy. In contrast, neither Hcy nor simvastatin had any effect on Nox4 expression. These findings indicate that simvastatin prevents the detrimental effects of Hcy on the apoptosis of osteocytes by regulating the expressions of Nox1 and Nox2, suggesting that statins may be beneficial for preventing Hcy-induced osteocyte apoptosis and the resulting bone fragility.

Secondary hyperparathyroidism prevalence and profile, between diabetic and non-diabetic patients with stage 3 to 4 chronic kidney disease attended in internal medicine wards. MiPTH study

AIMS

Secondary hyperparathyroidism (SHPTH) is a leading cause of renal osteodystrophy, and an independent risk factor for all-cause and cardiovascular mortality. Our aim is to establish differences in prevalence and profile of SHPTH, regarding diabetics or non-diabetics with chronic kidney disease (CKD).

METHODS

Cross-sectional multicenter study which included patients with stages 3 to 4 CKD. SHPTH was considered when the intact PTH levels (iPTH) were equal or higher than 70pg/ml. We divided the sample into two groups (diabetics and non-diabetics). We used robust statistical methods.

RESULTS

409 patients (214 diabetics) were studied. HPTH was found in 60.4% of diabetics vs 65% of non-diabetics (P=0.42). Diabetics with HPTH were younger (79.5 vs 82.3 years-old, P=0.005), and had more hypertension (P=0.0014), dyslipidemia (P=0.0001) and comorbidities. In multivariate analysis, we found a significant relationship in case of diabetics, with age (OR: 1.04, 95%CI 1.005-1.09 P=0.02 ), and with statins treatment (OR 2.3, 95%CI 1.17-4.54, P=0.01).

DISCUSSION

The prevalence of SHPTH between the groups was similar, however, diabetics had more presence of hypertension and dyslipidemia, and SHPTH in this case was also related with moderate microalbuminuria and lower levels of vitamin D. An association with statins was also found in this group.

Localized rosuvastatin via implantable bioerodible sponge and its potential role in augmenting bone healing and regeneration

OBJECTIVE

Statins proved potential bone healing properties. Rosuvastatin is a synthetic, hydrophilic, potent and highly efficacious statin. In the current work, an attempt was investigated to develop, evaluate various bioerodible composite sponges enclosing rosuvastatin and explore their potential in augmenting bone healing and regeneration.

METHOD

Twelve lyophilized sponge formulae were prepared adapting a 4¹.3¹ full factorial design. Xanthan gum, polycarbophil, Carbopol® and sodium alginate were investigated as anionic polymers, each at three chitosan:anionic polymer ratios (1:3, 1:1, 3:1). The formula of choice was implanted in fractured rat femora.

RESULTS

Visual and microscopic examination showed flexible homogenous porous structures with considerable bending ability. Polyelectrolyte complex formation was proved by DSC and FT-IR for all chitosan/anionic combinations except with xanthan gum where chitosan probably bound to the drug rather than xanthan gum. Statistical analysis proved that anionic polymer type and chitosan: polymer ratio, as well as, their interactions, exhibited significant effects on the release parameters at p ≤ 0.05. The optimum chitosan/anionic polymer complexation ratios were 3:1 for polycarbophil and 1:1 for Carbopol and alginate. The release at these ratios followed Fiction diffusion while other ratios had anomalous diffusion. Imwitor® 900K and HPMC K100M were added as release retarardants for further release optimization. The formula of choice was implanted in fractured rat femora. Histopathological examination revealed advanced stages of healing in treated femora compared to control ones.

CONCLUSION

Biodegradable sponges for local rosuvastatin delivery proved significantly enhanced wound healing and regeneration properties to fractured bones.

Naringin rescued the TNF-α-induced inhibition of osteogenesis of bone marrow-derived mesenchymal stem cells by depressing the activation of NF-кB signaling pathway

Naringin exhibits antiinflammatory activity and is shown to induce bone formation. Yet the impact of naringin on inflammation-affected bone marrow-derived mesenchymal stem cell (BM-MSC), a promising tool for the regenerative treatment of bone injury, remained to be investigated. We first cultured and characterized the BM-MSCs in vitro and observe the effects of treatments of TNF-α, naringin, or the combination of both on osteogenic differentiation. TNF-α administered at the concentration of 20 ng/ml results in significant reductions in MSC's cell survival, alkaline phosphatase activity and expressions of two osteogenic genes, Runx2 and Osx. Simultaneous treatment of both TNF-α and naringin is able to rescue such reductions. Further mechanistic studies indicate that TNF-α treatment activates the NF-кB signaling pathway, evidenced by elevated p-IкBα level as well as the increased nuclear fraction of NF-кB subunit, p65. Finally, treatment with both TNF-α and naringin decreases expressions of p-IкBα and nuclear p65, and thus represses NF-кB pathway activated by sole TNF-α treatment. Our findings provide a molecular basis by which naringin restores the TNF-α-induced damage in MSCs and provide novel insights into the application of naringin in the MSC-based treatments for inflammation-induced bone injury.

Simvastatin and zinc synergistically enhance osteoblasts activity and decrease the acute response of inflammatory cells

Several ceramic biomaterials have been suggested as promising alternatives to autologous bone to replace or restore bone after trauma or disease. The osteoinductive potential of most scaffolds is often rather low by themselves and for this reason growth factors or drugs have been supplemented to these synthetic materials. Although some growth factors show good osteoinductive potential their drawback is their high cost and potential severe side effects. In this work the combination of the well-known drug simvastatin (SVA) and the inorganic element Zinc (Zn) is suggested as a potential additive to bone grafts in order to increase their bone regeneration/formation. MC3T3-E1 cells were cultured with Zn (10 and 25 µM) and SVA (0.25 and 0.4 µM) for 10 days to evaluate proliferation and differentiation, and for 22 days to evaluate secretion of calcium deposits. The combination of Zn (10 µM) and SVA (0.25 µM) significantly enhanced cell differentiation and mineralization in a synergetic manner. In addition, the release of reactive oxygen species (ROS) from primary human monocytes in contact with the same concentrations of Zn and SVA was evaluated by chemiluminescence. The combination of the additives decreased the release of ROS, although Zn and SVA separately caused opposite effects. This work shows that a new combination of additives can be used to increase the osteoinductive capacity of porous bioceramics.

The functional mechanism of simvastatin in experimental osteoporosis

Osteoporosis is a systemic and metabolic bone disease. New drugs with good curative effect, fewer side effects, and high safety need to be developed urgently. Recently, simvastatin has been used to treat osteoporosis more frequently; however, its clinical effect and treatment mechanism are still unknown. With the use of animal models, the treatment effectiveness of simvastatin on experimental osteoporosis was investigated and the functional mechanism was preliminarily explored. The results show that simvastatin significantly increased the mechanical parameters such as maximum load, stiffness, and energy-absorbing capacity, and improved the microarchitecture. They indicated that the antiosteoporosis activity of simvastatin may be due to the promotion of proliferation and differentiation of osteoblasts. Simvastatin was effective in treating experimental osteoporosis. This study provides necessary experimental evidence for the clinical application of simvastatin in osteoporosis treatment.

The effect of simvastatin on relapse of tooth movement and bone mineral density in rats measured by a new method using microtomography

PURPOSE

To evaluate the effect of simvastatin on relapse of tooth movement in rats using microtomography (micro CT), as well as the correlation of bone density with the orthodontic relapse.

METHODS

Twenty-five adult male Wistar rats, divided into two groups, had stainless steel springs installed on left maxillary first molar. The molars were moved for 18 days, and after removing the springs, were applied by oral gavage, 5mg/kg of simvastatin in the experimental group for 20 days. Tooth relapse was assessed with a micro CT scanner, and the images chosen through the Data Viewer software 1.5.0.0 had their measurement guides made and checked by the software Image ProR plus 5.1, and compared by Mann-Whitney test. After rats were sacrificed, bone mineral density was evaluated by micro CT through the software CT Analyzer 1.13 and compared by independent T-test, as well as by Spearman correlation test.

RESULTS

Relapse and bone mineral density (BMD) was lower in the experimental group than in the control group, however without a statistically significant difference.

CONCLUSION

Simvastatin did not inhibit the relapse of tooth movement in rats, and there was no correlation between bone density and orthodontic relapse.

The effect of simvastatin treatment on bone repair of femoral fracture in animal model

The aim of this research was to evaluate the fracture healing area in osteoporotic femur of female rats restrained by stainless steel wire by statin administration in two different doses (5 mg and 20 mg). Ninety female rats were divided into six groups (n = 15): SH, SH-5 mg, SH-20 mg, OVX, OVX-5 mg, and OVX-20 mg. The surgery consisted of the fracture of the left femur bone and stabilization by K-wire and the administration was restricted and weekly controlled in the drinking water. The euthanasia was conducted at three different moments, five animals per period: 7 d, 14 d, and 28 d. Densitometry, zymography, and histological analyses showed a significant difference between some groups. According to these findings, simvastatin promoted a positive action for bone repair, especially in the osteometabolic group treated with 20 mg of the drug.