Effect of bisphosphonate treatment of titanium surfaces on alkaline phosphatase activity in osteoblasts: a systematic review and meta-analysis

CeO2 Nanoparticle Bioactive Materials Promote MG-63 Osteogenic Differentiation and Antioxidant Activity Through NRF2 Signaling

The incidence of bone-related diseases is higher in the elderly population, which greatly affects the patients' quality of life. Throughout this research, we synthesized a biocomposite nanomaterial of CeO2. The unique structural characteristics of CeO2 nanoparticles (CeO2 NPs) were studied by means of XRD, TEM, and SEM. Nanoparticles of an osteosarcoma cell line (MG-63) were assayed for ALP enzyme levels, key proteins in osteoblasts, and stained with Alizarin Red S to assess the physical properties, bioactivity, and calcium deposition of the osteosarcoma cell line. Moreover, we used H2O2 to construct an oxidative stress model to evaluate the antioxidant activity of CeO2 NPs. Experimental data showed that the CeO2 NPs increased the antioxidant capacity of MG-63 cells and significantly increased alkaline phosphatase activity, calcium deposition, and bone growth as manifested by increased expression of bone differentiation proteins BMP2, OCN, OPN, and type I collagen. Interestingly, RNA interference and functional recovery experiments confirmed that CeO2 NPs enhanced the antioxidant activity of MG-63 cells related to NRF2 signaling. In conclusion, the material is expected to be a potential treatment for bone-related diseases.

Assessing bone formation on hydrophilic and hydrophobic implant surfaces in a murine model treated with bisphosphonates

OBJECTIVE

To evaluate the osseointegration of implants with hydrophobic (HFB) and hydrophilic (HFL) surfaces in a murine model of high-dose bisphosphonates (BPs).

MATERIALS AND METHODS

Sixty-four rats were randomly allocated into four groups: control group with HFB implants (CG-HFB), control group with HFL implants (CG-HFL), BP group with HFB implants (BP-HFB), and BP group with HFL implants (BP-HFL). Animals were euthanized after 15 and 45 days (n=8). The dependent variables assessed were the removal torque (biomechanical analysis), the bone volume around the implants (%BV/TV) (microtomographic analysis), the bone-implant contact (%BIC), the bone between the threads (%BBT) (histomorphometric analysis), and the expression of bone metabolism markers (immunohistochemistry analysis).

RESULTS

The CG-HFL and BP-HFL groups presented higher removal torque than the CG-HFB and BP-HFB implants. The %BIC of the CG-HFL surfaces was slightly higher than that of the CG-HFB implants. The BP-HFB and BP-HFL groups presented a higher %BIC than that of the CG-HFB and CG-HFL groups (p<0.001). BP therapy also increased the %BBT at both implant surfaces. Higher levels of ALP were observed in the matrix region of bone tissue on the HFL surfaces than on the HFB surfaces.

CONCLUSION

Both surfaces enable osseointegration in rats under BP therapy.

CLINICAL RELEVANCE

The study demonstrates that hydrophobic (HFB) and hydrophilic (HFL) implant surfaces can promote osseointegration in rats undergoing bisphosphonate therapy. The HFL surfaces exhibited improved biomechanical performance, higher bone-implant contact, and increased bone volume, suggesting their potential clinical relevance for implant success in individuals on bisphosphonate treatment.

Effects of Growth Factors on the Differentiation of Dental Stem Cells: A Systematic Review and Meta-analysis (Part I)

INTRODUCTION

To evaluate the biological interaction between dental stem cells (DSCs) and different growth factors in the field of regenerative endodontics.

METHODS

A systematic search was conducted in the electronic databases up to October 2021. This study followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Ex vivo studies evaluating the biological interactions of DSCs and growth factors were included. The meta-analysis was performed according to the type of growth factor. The outcomes were cell viability/ proliferation and mineralization. Standardized mean differences (SMDs) were estimated using the random-effect maximum-likelihood method (P < .05). Additional analysis was performed to find any potential source of heterogeneity.

RESULTS

Twenty articles were included in the systematic review; meta-analysis was performed for fibroblast growth factor-2 (FGF-2) and Transforming growth factor-ß1 (TGF-β1) (n = 5). Results showed that use of FGF-2 significantly increased cell proliferation on day 1-(SMD = 3.56, P = 0.00), 3-(SMD = 9.04, P = 0.00), 5-(SMD = 8.37, P = 0.01), and 7 (SMD=8.51, P=0.00) than the control group. TGF-ß1 increased alkaline phosphatase (ALP) activity more than control only on day 3 (SMD = 3.68, P = 0.02). TGF-β1 had no significant effect on cell proliferation on days 1 and 3 (P > 0.05) and on ALP activity on days 5 and 7 (P > 0.05). Meta-regression analysis showed that different covariates (i.e., cell type, passage number, and growth factors' concentration) could significantly influence the effect sizes at different follow- ups (P < 0.05).

CONCLUSION

Specific growth factors might enhance the proliferation and mineralization of DSCs; however, the obtained evidence was weak. Due to the high heterogeneity among the included studies, other growth factors' inhibitory/stimulatory effects on DSCs could not be evaluated.

Bisphosphonate-incorporated coatings for orthopedic implants functionalization

Bisphosphonates (BPs), the stable analogs of pyrophosphate, are well-known inhibitors of osteoclastogenesis to prevent osteoporotic bone loss and improve implant osseointegration in patients suffering from osteoporosis. Compared to systemic administration, BPs-incorporated coatings enable the direct delivery of BPs to the local area, which will precisely enhance osseointegration and bone repair without the systemic side effects. However, an elaborate and comprehensive review of BP coatings of implants is lacking. Herein, the cellular level (e.g., osteoclasts, osteocytes, osteoblasts, osteoclast precursors, and bone mesenchymal stem cells) and molecular biological regulatory mechanism of BPs in regulating bone homeostasis are overviewed systematically. Moreover, the currently available methods (e.g., chemical reaction, porous carriers, and organic material films) of BP coatings construction are outlined and summarized in detail. As one of the key directions, the latest advances of BP-coated implants to enhance bone repair and osseointegration in basic experiments and clinical trials are presented and critically evaluated. Finally, the challenges and prospects of BP coatings are also purposed, and it will open a new chapter in clinical translation for BP-coated implants.

A Novel Porous Butyryl Chitin-Animal Derived Hydroxyapatite Composite Scaffold for Cranial Bone Defect Repair

Bone defects, a common orthopedic problem in clinical practice, are a serious threat to human health. As alternative materials to autologous bone grafts, synthetic cell-free functionalized scaffolds have been the focus of recent research in designing scaffolds for bone tissue engineering. Butyryl chitin (BC) is a derivative of chitin (CT) with improved solubility. It has good biocompatibility, but few studies have investigated its use in bone repair. In this study, BC was successfully synthesized with a degree of substitution of 2.1. BC films were prepared using the cast film method and showed strong tensile strength (47.8 ± 4.54 N) and hydrophobicity (86.4 ± 2.46°), which was favorable for mineral deposition. An in vitro cytological assay confirmed the excellent cell attachment and cytocompatibility of the BC film; meanwhile, in vivo degradation indicated the good biocompatibility of BC. Hydroxyapatite (HA), extracted from bovine cancellous bone, had good cytocompatibility and osteogenic induction activity for the mouse osteoblast cell line MC3T3-E1. With the aim of combining the advantages of BC and HA, a BC-HA composite scaffold, with a good pore structure and mechanical strength, was prepared by physical mixing. Administered into skull defects of rats, the scaffolds showed perfect bone-binding performance and effective structural support, and significantly promoted the regeneration of new bone. These results prove that the BC-HA porous scaffold is a successful bone tissue engineering scaffold and has strong potential to be further developed as a substitute for bone transplantation.

Isolation, Identification, and Characterization of Bioactive Peptides in Human Bone Cells from Tortoiseshell and Deer Antler Gelatin

Tortoiseshell and deer antler gelatin has been used to treat bone diseases in Chinese society. A pepsin-digested gelatin peptide with osteoblast-proliferation-stimulating properties was identified via LC-MS/MS. The resulting pentapeptide, TSKYR, was presumably subjected to further degradation into TSKY, TSK, and YR fragments in the small intestine. The above four peptides were chemically synthesized. Treatment of tripeptide TSK can lead to a significant 30- and 50-fold increase in the mineralized nodule area and density in osteoblast cells and a 47.5% increase in the number of chondrocyte cells. The calcium content in tortoiseshell was relatively higher than in human soft tissue. The synergistic effects of calcium ions and the peptides were observed for changes in osteoblast proliferation and differentiation. Moreover, these peptides can enhance the expression of RUNX2, OCN, FGFR2, and FRFR3 genes in osteoblasts, and aggrecan and collagen type II in chondrocyte (patent pending).

Synergistic effects of enamel matrix derivatives and surface morphology of anodized titanium on osteogenic differentiation of bone marrow mesenchymal stem cells sheet

OBJECTIVE

To explore the potential osteogenic induction mechanism of enamel matrix derivatives (EMDs) on bone marrow mesenchymal stem cell (BMSC) sheets with different titanium surface morphologies.

METHODS

The BMSCs were inoculated on the surfaces of titanium alloys with different morphologies: anodic oxidation (AO), sand-blasted, large grit and acid-etched, and no treatment (control). The proliferation and osteogenic differentiation of BMSCs on the different surface morphologies were observed with the same concentration of EMDs. To further understand the osteogenic mechanism of EMDs on BMSC sheets with different morphologies, a real-time RT-PCR and a western blot were used to detect the overall levels of osteogenic genes and osteogenic proteins. Finally, to verify the osteogenic effect of BMSC sheets stimulated by EMDs in vivo, BMSC sheets with different morphologies were implanted into the subcutaneous tissue of the back of nude mice, and the bone formation was detected by HE staining.

RESULTS

The EMDs and surface morphology in the AO group synergically increased the expression levels of osteogenic active factors (RUNX2, OSX and OCN) and enhanced the osteogenic differentiation effect of BMSCs. The in vivo experiments showed that the BMSC sheets in the AO group were rich in osteogenic active factors, and promoted the formation of ectopic bone tissue after implantation into the subcutaneous tissue of the back of nude mice.

CONCLUSION

EMDs and AO morphology synergically enhance the secretion of bone osteogenic active factors of BMSCs and promote the formation of heterotopic bone.

Drug distribution evaluation using FT-IR imaging on the surface of a titanium alloy coated with zinc titanate with potential application in the release of drugs for osteoporosis

The drugs most commonly used in the treatment of osteoporosis are bisphosphonates. This disease results in low mineral density and a weakened bone microstructure. The delivery methods for these drugs have many disadvantages, and new ones are being searched for. In this work, biocompatible zinc titanate coated titanium implants were obtained as potential new carriers for drugs. Such a material will release the drug, and it will have antibacterial properties. Gradual release of the bisphosphonate will have a positive effect on the recovery process and osteointegration. In addition, the drug will be released around the affected bones. The effectiveness of the modification and attachment of the drug was confirmed by SEM, XPS, EDS, FT-IR imaging, and UV-VIS. It was shown that the risedronate could be almost completely released upon contact with body fluids within a week. The drug is evenly distributed over the entire surface of the alloy as confirmed by FT-IR imaging. The results presented in this work will allow for the preparation of endoprostheses that release the drug and have antibacterial properties.

Construction of Local Drug Delivery System on Titanium-Based Implants to Improve Osseointegration

Titanium and its alloys are the most widely applied orthopedic and dental implant materials due to their high biocompatibility, superior corrosion resistance, and outstanding mechanical properties. However, the lack of superior osseointegration remains the main obstacle to successful implantation. Previous traditional surface modification methods of titanium-based implants cannot fully meet the clinical needs of osseointegration. The construction of local drug delivery systems (e.g., antimicrobial drug delivery systems, anti-bone resorption drug delivery systems, etc.) on titanium-based implants has been proved to be an effective strategy to improve osseointegration. Meanwhile, these drug delivery systems can also be combined with traditional surface modification methods, such as anodic oxidation, acid etching, surface coating technology, etc., to achieve desirable and enhanced osseointegration. In this paper, we review the research progress of different local drug delivery systems using titanium-based implants and provide a theoretical basis for further research on drug delivery systems to promote bone–implant integration in the future.

Dentin Matrix Protein 1 Silencing Inhibits Phosphorus Utilization in Primary Cultured Tibial Osteoblasts of Broiler Chicks

Three experiments were carried out in the present study to investigate whether dentin matrix protein 1 (DMP1) was involved in regulating phosphorus (P) metabolic utilization in primary cultured tibial osteoblasts of broiler chicks. Experiment 1 was conducted to select the optimal osteogenic inductive culture medium and the optimal induction time in primary cultured tibial osteoblasts of broiler chicks. In experiment 2, the siRNAs against DMP1 were designed, synthesized and transfected into primary cultured tibial osteoblasts of broiler chicks, and then the inhibitory efficiencies of siRNAs against DMP1 were determined, and the most efficacious siRNA was selected to be used for the DMP1 silencing. In experiment 3, with or without siRNA against DMP1, primary cultured tibial osteoblasts of broiler chicks were treated with the medium supplemented with 0.0, 1.0 or 2.0 mmol/L of P as NaH₂PO₄ for 12 days. The P metabolic utilization-related parameters were measured. The results showed that the osteogenic induced medium 2 and 12 days of the optimal induction time were selected; Among the designed siRNAs, the si340 was the most effective (P < 0.05) in inhibiting the DMP1 expression; DMP1 silencing decreased (P < 0.05) the expressions of DMP1 mRNA and protein, P retention rate, mineralization formation, alkaline phosphatase activity and bone gla-protein content in tibial osteoblasts at all of added P levels. It is concluded that DMP1 silencing inhibited P utilization, and thus DMP1 was involved in regulating P metabolic utilization in primary cultured tibial osteoblasts of broiler chicks, which provides a novel insight into the regulation of the P utilization in the bone of broilers, and will contribute to develop feasible strategies to improve the bone P utilization efficiency of broilers so as to decrease its excretion.

Involvement of MiRNA-211-5p and Arhgap11a Interaction During Osteogenic Differentiation of MC3T3-E1 Cells

Objective

MicroRNAs (miRNAs) are well-recognized for their abilities to regulate gene expression post-transcriptionally in plants and animals. Recently, miRNA-messenger RNA (mRNA) regulatory relationships have been confirmed during biological processes, including osteogenic differentiation. This study aimed to find out more candidate miRNA-mRNA pairs involved in the osteogenic differentiation of MC3T3-E1 cells.

Methods

An MC3T3-E1-based microarray dataset (accessioned as GSE46400) downloaded from the Gene Expression Omnibus included MC3T3-E1 cells with or without 14-day osteoblast differentiation osteoblast induction. Multiple miRNA-mRNA prediction databases were searched by differentially expressed genes (DEGs) to obtain pairs of a miRNA-DEG regulatory network. The MC3T3-E1 cells were cultured and incubated in the osteogenic differentiation medium for 14 days. The expressions of candidate miRNAs and mRNAs were determined by real-time quantitative PCR(RT-qPCR) in MC3T3-E1 cells. The miRNA-mRNA interactions were verified by dual-luciferase reporter gene assays and experiments using mimics miRNA or their inhibitors.

Results

We identified 715 upregulated DEGs and 603 downregulated DEGs between MC3T3-E1 cells with and without osteoblast induction by analyzing the raw data of the GSE46400 dataset. There were 7 overlapped miRNA-mRNA pairs identified during osteogenic differentiation of MC3T3-E1 cells, including mmu-miR-204-5p-Arhgap11a, mmu-miR-211-5p-Arhgap11a, mmu-miR-24-3p-H2afx, mmu-miR-3470b-Chek2, mmu-miR-3470b-Dlgap5, mmu-miR-466b-3p-Chek1, and mmu-miR-466c-3p-Chek1. The Arhgap11a, H2afx, Chek2, Dlgap5, and Chek1 were hub genes downregulated in MC3T3-E1 cells after osteogenic differentiation, verified by RT-qPCR results. The RT-qPCR also determined declined expressions of miR-204-5p and miR-24-3p concomitant with elevated expressions of miR-211-5p, miR-3470b, miR-466b-3p, and miR-466c-3p in the MC3T3-E1 cells, with osteoblast induction compared with undifferentiated MC3T3-E1 cells. Dual-luciferase reporter gene assays demonstrated Arhgap11a as the target of miR-211-5p. MiR-211-5p upregulation by its mimic increased Arhgap11a expression in MC3T3-E1 cells.

Conclusion

Our study characterizes miR-211-5p targeting Arhgap11a promotes the osteogenic differentiation of MC3T3-E1 cells, which provides novel targets to promote the osteogenesis process during bone repair.

Titanium with nanotopography attenuates the osteoclast-induced disruption of osteoblast differentiation by regulating histone methylation

The bone remodeling process is crucial for titanium (Ti) osseointegration and involves the crosstalk between osteoclasts and osteoblasts. Considering the high osteogenic potential of Ti with nanotopography (Ti Nano) and that osteoclasts inhibit osteoblast differentiation, we hypothesized that nanotopography attenuate the osteoclast-induced disruption of osteoblast differentiation. Osteoblasts were co-cultured with osteoclasts on Ti Nano and Ti Control and non-co-cultured osteoblasts were used as control. Gene expression analysis using RNAseq showed that osteoclasts downregulated the expression of osteoblast marker genes and upregulated genes related to histone modification and chromatin organization in osteoblasts grown on both Ti surfaces. Osteoclasts also inhibited the mRNA and protein expression of osteoblast markers, and such effect was attenuated by Ti Nano. Also, osteoclasts increased the protein expression of H3K9me2, H3K27me3 and EZH2 in osteoblasts grown on both Ti surfaces. ChIP assay revealed that osteoclasts increased accumulation of H3K27me3 that represses the promoter regions of Runx2 and Alpl in osteoblasts grown on Ti Control, which was reduced by Ti Nano. In conclusion, these data show that despite osteoclast inhibition of osteoblasts grown on both Ti Control and Ti Nano, the nanotopography attenuates the osteoclast-induced disruption of osteoblast differentiation by preventing the increase of H3K27me3 accumulation that represses the promoter regions of some key osteoblast marker genes. These findings highlight the epigenetic mechanisms triggered by nanotopography to protect osteoblasts from the deleterious effects of osteoclasts, which modulate the process of bone remodeling and may benefit the osseointegration of Ti implants.

The Effects of Local Alendronate With or Without Recombinant Human Bone Morphogenetic Protein 2 on Dental Implant Stability and Marginal Bone Level: A Randomized Controlled Study

ABSTRACT

The aim of this study was to evaluate the effects of local application of bisphosphonate gel and recombinant human bone morphogenic protein 2 gel, on titanium dental implant stability and marginal bone level. Twenty-seven patients with upper and lower missing posterior tooth/teeth were included in the study with a total of 71 implants that were used for rehabilitation. The implants were randomly divided into 4 groups: 3 study groups and 1 control. Group1; local application of bisphosphonate gel, group 2; local application of recombinant human bone morphogenic protein 2 gel, group 3; local application of a mixed formula of both gels. The gel application was immediately preimplant insertion, group 4; implant insertion without application of any medication. Using resonance frequency analyzer, implant stability was measured 4 times; primary, 8 weeks (second stage surgery), 12 weeks, and at least 14 weeks post functional loading. The level of the marginal bone around each implant were assessed using cone beam computed tomography. Four implants failed. Generally, there was a similar pattern of changes in implant stability over the study period in all groups and the stability was dependent on the healing time with no significant difference between groups. There was no significant treatment effect regarding marginal bone level differences of study groups against control, although there were significant differences on palatal and mesiodistal surfaces among the study (test) groups.

Effects of bisphenols on Blood-Testis Barrier protein expression in vitro: A systematic review and meta-analysis

Bisphenols are a group of environmental endocrine-disrupting chemicals that produce alterations in the expression of intercellular junction proteins of the Blood-Testis Barrier (BTB) involved in spermatogenesis. The association between bisphenol exposure and BTB protein expression is controversial. Therefore, we performed this systematic review and meta-analysis to clarify bisphenol effects on Sertoli cell BTB protein expression in vitro. The Standardized Mean Difference (SMD) with a 95 % confidence interval (95 % CI) was used to evaluate the association between alterations in the BTB protein expression and bisphenol exposure in vitro. Six articles were included in the meta-analysis. Bisphenol-A (BPA) exposure at 200 μM was associated with significant decrease in BTB protein expression (SMD = -2.70, 95 %CI: -3.59, -1.80, p het = 0.46, p = <0.00001). In the moderate (40-50 μM) and low dose (<25 μM), no significant associations were obtained. We also found a non-monotonic dose-response curve of bisphenol effect in ZO-1 protein expression; low and high doses presented a significant decrease compared to control, while moderate dose presented no change. The current temporary Tolerable Daily Intake (tTDI) of BPA is 4 μg/kg bw/day. The 5-25 μM doses of BPA are equivalent to ∼1-5 mg/kg bw, respectively. Although the low dose group (<25 μM) assessed doses below the previous NOAEL value, these doses are above the current tTDI. Thus, it is necessary to conduct more studies with lower bisphenol concentrations to avoid underestimating the potential adverse effects of bisphenols at doses below tTDI.

LGALS3BP/Gal-3 promotes osteogenic differentiation of human periodontal ligament stem cells

OBJECTIVE

To identify the role of LGALS3BP/Gal-3 in the process of human periodontal ligament stem cells (hPDLSCs) differentiating into osteoblasts.

METHODS

IP-WB experiments were carried out to examine the binding of LGALS3BP and Gal-3. Western blot was performed to detect the expressions of LGALS3BP and Gal-3 in hPDLSCs with or without osteogenic differentiation inducement. The expressions of differentiation-related Oct4, Sox2 and Runx2 were also detected by western blot. Alkaline Phosphatase (ALP) Assay Kit was used to measure ALP activity in hPDLSCs. The mineralization ability of hPDLSCs was observed by staining with Alizarin Red S solution.

RESULTS

LGALS3BP bound with Gal-3 in hPDLSCs, and the expression of LGALS3BP and Gal-3 was improved after osteogenic differentiation of hPDLSCs. Recombinant GAL-3 promoted the expression of differentiation-related proteins Oct4 and Sox2 and Runx2 in osteogenic differentiation-induced hPDLSCs. Recombinant GAL-3 also promoted the differentiation of osteogenesis-induced hPDLSCs. Furthermore, LGALS3BP had a facilitating effect on differentiation-related protein expression, while it could be reversed by shGal-3. LGALS3BP also promoted osteogenic capacity of hPDLSCs, and shGal-3 could reverse this effect.

CONCLUSION

LGALS3BP binds to Gal-3, producing a promoting effect on the osteogenic differentiation of human periodontal ligament stem cells.

Quality assessment tools used in systematic reviews of in vitro studies: A systematic review

BACKGROUND

Systematic reviews (SRs) and meta-analyses (MAs) are commonly conducted to evaluate and summarize medical literature. This is especially useful in assessing in vitro studies for consistency. Our study aims to systematically review all available quality assessment (QA) tools employed on in vitro SRs/MAs.

METHOD

A search on four databases, including PubMed, Scopus, Virtual Health Library and Web of Science, was conducted from 2006 to 2020. The available SRs/MAs of in vitro studies were evaluated. DARE tool was applied to assess the risk of bias of included articles. Our protocol was developed and uploaded to ResearchGate in June 2016.

RESULTS

Our findings reported an increasing trend in publication of in vitro SRs/MAs from 2007 to 2020. Among the 244 included SRs/MAs, 126 articles (51.6%) had conducted the QA procedure. Overall, 51 QA tools were identified; 26 of them (51%) were developed by the authors specifically, whereas 25 (49%) were pre-constructed tools. SRs/MAs in dentistry frequently had their own QA tool developed by the authors, while SRs/MAs in other topics applied various QA tools. Many pre-structured tools in these in vitro SRs/MAs were modified from QA tools of in vivo or clinical trials, therefore, they had various criteria.

CONCLUSION

Many different QA tools currently exist in the literature; however, none cover all critical aspects of in vitro SRs/MAs. There is a need for a comprehensive guideline to ensure the quality of SR/MA due to their precise nature.

Bisphosphonates Reduce Smoking-Induced Osteoporotic-Like Alterations by Regulating RANKL/OPG in an Osteoblast and Osteoclast Co-Culture Model

Co-culture models have become mandatory for obtaining better insights into bone homeostasis, which relies on the balance between osteoblasts and osteoclasts. Cigarette smoking (CS) has been proven to increase the risk of osteoporosis; however, there is currently no proven treatment for osteoporosis in smokers excluding cessation. Bisphosphonates (BPs) are classical anti-osteoclastic drugs that are commonly used in examining the suitability of bone co-culture systems in vitro as well as to verify the response to osteoporotic stimuli. In the present study, we tested the effects of BPs on cigarette smoke extract (CSE)-affected cells in the co-culture of osteoblasts and osteoclasts. Our results showed that BPs were able to reduce CSE-induced osteoporotic alterations in the co-culture of osteoblasts and osteoclasts such as decreased matrix remodeling, enhanced osteoclast activation, and an up-regulated receptor activator of nuclear factor (NF)-kB-ligand (RANKL)/osteoprotegerin (OPG) ratio. In summary, BPs may be an effective alternative therapy for reversing osteoporotic alterations in smokers, and the potential mechanism is through modulation of the RANKL/OPG ratio.