Bone morphogenetic protein-6 suppresses TGF-β_(2)-induced epithelial-mesenchymal transition in retinal pigment epithelium

AIM:To evaluate the effect of bone morphogenetic protein-6(BMP-6)on transforming growth factor(TGF)-β_(2)-induced epithelial-mesenchymal transition(EMT)in retinal pigment epithelium(RPE).METHODS:Adult retinal pigment epithelial cell line(ARPE-19)were randomly divided into control,TGF-β_(2)(5μg/L),and BMP-6 small interfering RNA(siRNA)group.The cell morphology was observed by microscopy,and the cell migration ability were detected by Transwell chamber.The EMT-related indexes and BMP-6 protein levels were detected by Western blotting.Furthermore,a BMP-6 overexpression plasmid was constructed and RPE cells were divided into the control group,TGF-β_(2)+empty plasmid group,BMP-6 overexpression group,and TGF-β_(2)+BMP-6 overexpression group.The EMT-related indexes and extracellular regulated protein kinases(ERK)protein levels were detected.RESULTS:Compared with the control group,the migration of RPE cells in the TGF-β_(2) group was significantly enhanced.TGF-β_(2) increased the protein expression levels ofα-smooth muscle actin(α-SMA),fibronectin and vimentin but significantly decreased the protein levels of E-cadherin and BMP-6(P<0.05)in RPE.Similarly,the migration of RPE cells in the BMP-6 siRNA group was also significantly enhanced.BMP-6 siRNA increased the protein expression levels ofα-SMA,fibronectin and vimentin but significantly decreased the protein expression levels of E-cadherin(P<0.05).Overexpression of BMP-6 inhibited the migration of RPE cells induced by TGF-β_(2) and prevented TGF-β_(2) from affecting EMT-related biomarkers(P<0.05).CONCLUSION:BMP-6 prevents the EMT in RPE cells induced by TGF-β_(2),which may provide a theoretical basis for the prevention and treatment of proliferative vitreoretinopathy.

Drilling Combined with Adipose-derived Stem Cells and Bone Morphogenetic Protein-2 to Treat Femoral Head Epiphyseal Necrosis in Juvenile Rabbits

This study was designed to evaluate the effects of drilling through the growth plate and using adipose-derived stem cells （ADSCs） and bone morphogenetic protein-2 （BMP-2） to treat femoral head epiphyseal ischemic necrosis, which can be done in juvenile rabbits. Passagefour bromodeoxyuridine （BrdU）-labeled ADSCs were cultured, assayed with MTT to determine their viability and stained with alizarin red dye to determine their osteogenic ability. Twomonth-old, healthy male rabbits （1.2 to 1.4 kg, n=45） underwent ischemic induction and were randomly divided into five groups （group A： animal model control; group B： drilling; group C： drilling ＆ ADSCs; group D： drilling ＆ BMP-2; and group E： drilling ＆ ADSCs ＆ BMP-2）. Magnetic resonance imaging （MRI）, X-ray imaging, hematoxylin and eosin staining and BrdU immunofluorescence detection were applied 4, 6 and 10 weeks after treatment. Approximately 90% of the ADSCs were labeled with BrdU and showed good viability and osteogenic ability. Similar results were observed in the rabbits in groups C and E at weeks 6 and 10. The animals of groups C and E demonstrated normal hip structure and improved femoral epiphyseal quotients and trabecular areas compared with those of the groups A and B （P〈0.01）. Group D demonstrated improved femoral epiphyseal quotients and trabecular areas compared with those of groups A and B （P〈0.05）. In summary, drilling through the growth plate combined with ADSC and BMP-2 treatments induced new bone formation and protected the femoral head epiphysis from collapsing in a juvenile rabbit model of femoral head epiphyseal ischemic necrosis.

Bone morphogenetic protein-2 is a negative regulator of hepatocyte proliferation downregulated in the regenerating liver

AIM: To characterize the expression and dynamic changes of bone morphogenetic protein (BMP)-2 in hepatocytes in the regenerating liver in rats after partial hepatectomy (PH), and examine the effects of BMP-2 on proliferation of human Huh7 hepatoma cells. METHODS: Fifty-four adult male Wistar rats were randomly divided into three groups: A normal control (NC) group, a partial hepatectomized (PH) group and a sham operated (SO) group. To study the effect of liver regeneration on BMP-2 expression, rats were sacrificed before and at different time points after PH or the sham intervention (6, 12, 24 and 48 h). For each time point, six rats were used in parallel. Expression and distribution of BMP-2 protein were determined in regenerating liver tissue by Western blot analysis and immunohistochemistry. Effects of BMP-2 on cell proliferation of human Huh7 hepatoma cell line were assessed using an MTT assay.RESULTS: In the normal liver strong BMP-2 expression was observed around the central and portal veins. The expression of BMP-2 decreased rapidly as measured by both immunohistochemistry and Western blot analysis. This decrease was at a maximum of 3.22 fold after 12 h and returned to normal levels at 48 h after PH. No significant changes in BMP-2 immunoreactivity were observed in the SO group. BMP-2 inhibited serum induced Huh7 cell proliferation.CONCLUSION: BMP-2 is expressed in normal adult rat liver and negatively regulates hepatocyte proliferation. The observed down regulation of BMP-2 following partial hepatectomy suggests that such down regulation may be necessary for hepatocyte proliferation.

Effect of dopamine on bone morphogenesis protein-2 expression in human retinal pigment epithelium

AIM：To investigate the effect of dopamine on bone morphogenesis protein-2（BMP-2）expression in retinal pigment epithelium（RPE）cells in vitro.METHODS：ARPE-19 cells as a human RPE cell line were cultured with dopamine for different times（2,4,6,8,12,16and 24h）or with different concentrations（0.1,1,2,5,10,20,and 100μg/m L）in vitro.BMP-2 m RNA expression level in ARPE-19 cells was analyzed with real-time polymerase chain reaction（PCR）analysis and BMP-2 protein level was measured with Western blot analysis.The active form of BMP-2 in the culture medium was measured with enzymelinked immunosorbent assay（ELISA）.RESULTS：The expression level of BMP-2 increased significantly cultured with 20μg/m L dopamine,at different time points（P〈0.05）.BMP-2 m RNA level peaked 2h and the protein level peaked at 6 and 8h after treatment.The concentrations of secreted BMP-2 elevated at 12h and peaked at 24h（P〈0.05）in a time-dependent manner.Treated with 100μg/m L dopamine for 6h,the expression levels of BMP-2 m RNA and protein in ARPE-19 cells were enhanced significantly compared to that in the untreated cells（P〈0.05）.And secreted BMP-2 protein in the cell culture supernatant was also increased（P〈0.05）.CONCLUSION：Dopamine up-regulate BMP-2 expression in RPE cells,and this may be associated with its inhibitive effect on myopia development.

Use of recombinant human bone morphogenetic protein-2 in spine surgery

Bone morphogenetic proteins are osteoinductive factors which have gained popularity in orthopaedicsurgery and especially in spine surgery. The use of recombinant human bone morphogenetic protein-2 has been officially approved by the United States Food and Drug Administration only for single level anterior lumbar interbody fusion, nevertheless it is widely used by many surgeons with off-label indications. Despite advantages in bone formation, its use still remains a controversial issue and several complications have been described by authors who oppose their wide use.

The Effect of Simvastatin on mRNA Expression of Transforming Growth Factor-β1,Bone Morphogenetic Protein-2 and Vascular Endothelial Growth Factor in Tooth Extraction Socket

Aim To determine the effect of local simvastatin application on the mRNA expression level of transforming growth factor-β1 （TGF-β1）, bone morphogenetic protein-2 （BMP-2） and vascular endothelial growth factor （VEGF） in the tooth sockets of rat. Methodology Forty-eight male Wistar rats were randomly divided into experimental and control groups （n=24）. Polylactic acid/polyglycolic acid copolymer carriers, with or without simvastatin, were implanted into extraction sockets of right mandibular incisors. The expression of TGF-β1, BMP-2 and VEGF mRNA was determined by in situ hybridization in the tooth extraction socket at five days, one week, two weeks and four weeks after implantation. Results The fusiform stroma cells in the tooth extraction socket began to express TGF-β1, BMP-2 and VEGF mRNA in both experimental and control groups from one week after tooth extraction until the end of experiment. The expression of TGF-131 and BMP-2 mRNA in the experimental group was significantly up-regulated after one, two and four weeks, and expression of VEGF mRNA was significantly increased after one and two weeks compared with that in the control group. Conclusion The findings indicate that local administration of simvastatin can influence alveolar bone remodeling by regulating the expression of a school of growth factors which are crucial to osteogenesis in the tooth extraction socket.

Regulation of scleral fibroblast differentiation by bone morphogenetic protein-2

Bone morphogenesis proteins(BMPs) are multi-functional growth factors. They are expressed in retina,retinal pigment epithelium(RPE) and sclera and serve as a regulator in the growth and development of the eye. This article reviewed the chondrogenic potency of the sclera,biochemical and pathological changes of myopic scleral tissue and the differentiation of chondrogenesis by BMP-2. We proposed the hypothesis that BMP-2 can regulate differentiate of scleral fibroblasts and affect the development of myopia.

Curcumin Inhibits Prostate Cancer Bone Metastasis by Up-Regulating Bone Morphogenic Protein-7 <i>in Vivo</i>

A number of studies have focused on the beneficial properties of Curcumin (diferuloyl methane, used in South Asian cuisine and traditional medicine) such as the chemoprevention of cancer. Recent studies have also indicated that this material has significant benefits for the treatment of cancer and is currently undergoing several clinical trials. We have been interested in the application of this compound as a therapeutic agent for advanced prostate cancer, particularly the skeletal complications in this malignancy. Our earlier work indicated that this compound could inhibit the osteomimetic properties which occur in castration resistant prostate cancer cells, by interfering with the common denominators between these cancer cells and the bone cells in the metastatic tumor microenvironment, namely the osteoblasts and the osteoclast. We predicted that curcumin could break the vicious cycle of reciprocal stimulation that results in uncontrolled osteolysis in the bony matrix. In this work, we have evaluated the potential of this compound in inhibiting the bone metastasis of hormone refractory prostate cancer cells in an established animal model. Our results strongly suggest that curcumin modulates the TGF-βsignaling that occurs due to bone matrix degradation by up-regulating the metastasis inhibitory bone morphogenic protein-7 (BMP-7). This enhancement of BMP-7 in the context of TGF-β in the tumor microenvironment is shown to enhance the mesenchymal-to-epithelial transition. Most importantly, we show that as a result of BMP-7 up-regulation, a novel brown/beige adipogenic differentiation program is also up-regulated which plays a role in the inhibition of bone metastasis. Our results suggest that curcumin may subvert the TGF-β signaling to an alternative adipogenic differentiation program in addition to the previously established interference with the osteomimetic properties, thus inhibiting the bone metastatic processes in a chemopreventive as well as therapeutic setting.

Effects of exogenous recombinant human bone morphogenic protein-7 on the corneal epithelial mesenchymal transition and fibrosis

AIM：To evaluate the effect of exogenous recombinant human bone morphogenic protein-7（rhBMP-7）on transforming growth factor-β（TGF-β）-induced epithelial mesenchymal cell transition（EMT）and assessed its antifibrotic effect via topical application.METHODS：The cytotoxic effect of rhBMP-7 was evaluated and the EMT of human corneal epithelial cells（HECEs）was induced by TGF-β. HECEs were then cultured in the presence of rhBMP-7 and/or hyaluronic acid（HA）. EMT markers,fibronectin,E-cadherin,α-smooth muscle actin（α-SMA）,and matrix metaloproteinase-9（MMP-9）,were evaluated. The level of corneal fibrosis and the reepithelization rate were evaluated using a rabbit keratectomy model. Expression of α-SMA in keratocytes were quantified following treatment with different concentrations of rhBMP-7.RESULTS：Treatment with rhBMP-7 attenuated TGF-β-induced EMT in HECEs. It significantly attenuated fibronectin secretion（31.6%; P〈0.05）,the α-SMA protein level（72.2%; P〈0.01）,and MMP-9 expression（23.6%,P〈0.05）in HECEs compared with cells grown in the presence of TGF-β alone. E-cadherin expression was significantly enhanced（289.7%; P〈0.01）in the presence of rhBMP-7. Topical application of rhBMP-7 combined with 0.1% HA significantly reduced the amount of α-SMA~＋ cells by 43.18%（P〈0.05）at a concentration of 2.5 μg/mL and by 47.73%（P〈0.05）at 25 μg/mL,compared with the control group,without disturbing corneal reepithelization.CONCLUSION：rhBMP-7 attenuates TGF-β-induced EMT in vitro,and topical application of rhBMP-7 reduces keratocyte myodifferentiation during the early wound healing stages in vivo without hindering reepithelization. Topical rhBMP-7 application as biological eye drops seems to be feasible in diseases involving TGF-β-related corneal fibrosis with corneal reepithelization disorders.

Alendronate disturbs femoral growth due to changes during immunolocalization of transforming growth factor-β1 and bone morphogenetic protein-2 in epiphyseal plate

BACKGROUND The epiphyseal growth plate is an important anatomical segment localized on the ends of a long bone.Despite the abovementioned atractive reasons for alendronate’s use,few data on the effect of alendronate during epiphyseal growth exist.AIM Verify the effect of alendronate on the growth epiphyseal plate,and compare its effect with the size of the femur during the double-staining of the immunolocalization of transforming growth factor-β1(TGF-β1)and bone morphogenetic protein-2(BMP2)in endochondral ossifing in specimens that have received alendronate.METHODS Forty newborn rats were randomly divided into two groups:a control group(were given applications of 1 mg/kg physiologic saline)and a group that received Alendronate(a dose of 2.5 mg/kg).These groups were then divided into two subgroups for euthanasia in two and 12 d of life.After euthanasia,the femurs were removed,and the femoral bones were measured linearly between the apex of the greater trochanter until the lower intercondylar midlle face to verify the probable bone growth between 3 and 12 d in control and alednroanto treated rats.Posteriorly,the surgical pieces were also sent to the histopathology laboratory to produce histological slides.The obtained slides were stained with hematoxylin and eosin to measure each of the cartilage zones in endochondral development.and other slides were immunohistochemically tested for anti-TGF-β1 and BMP-2 antibodies to investigate the immunolocalization of these proteins in the epiphyseal plaque area.RESULTS On the third day,some diferences between the control group and specimens treated with alendronate were verified.Macroscopiccaly,we found similarities in size between the femoral bones when we compared the control group with the specimens that received alendronate.On the 12^th day,the bone size of the mice receiving the drug was significantly smaller than those of the control group.These results coincide with changes in the TGF-β1 and BMP-2 expression.In the specimens that received alendronate,the TGF-β1 was expressed in some sites of trabecular bone that was neoformed,peripherally to the bone marrow area.The BMP-2 was also positive in proliferative chondrocytes and hypertrofic chondrocytes.On the 12^th day,all layers of chondrocytes exhibited positivity for BMP-2 in the specimens that received alendronate.In the interface between the trabecular bone and cartilage,an area of disorganized bone deposition was evident.Neoformed bone also appeared to be different at 12 d.In the control group,BMP-2 was positive in an intense area of bone trabeculae,whereas the alendronate-treated group showed TGF-β1 positive trabeculae and a greater bone area.CONCLUSION Alendronate alters the immunolocalization of TGF-β1 and BMP-2 simultaneously,a condition that changes the usual histological aspects of the cartilage zone and impairs epiphysis growth and femur growth.

Implantation of xenogeneic bone combined with recombinant human bone morphogenetic protein-2 into bone defect—An scanning electron microscopic study

To determine the ability of a new type of composite xenogeneic bone grafting to repair bone defect. Methods: The new type of composite xenogeneic bone was obtained by combining the chemically treated cance1lous bone with recombinant human bone morphogenetic protein-2 (rhBMP-2). It was implanted on the bone defect of rabbit. Results: There was a large amount of new bone formation within the combined material and the amount was increasing as the time elapsed. In contrast, there was a lot of fibrous tissue with a little new bone formed on the area of the bone defect when the treated cancellous bone was implanted alone. Conclusion: The results imply that the rhBMP-2 plays a very important role in new bone formation and the composite xenogeneic bone appear to be an ideal material for repair of bone defect.

Expression of mature peptide of human bone morphogenetic protein-2 in Escherichia coli

To express die mature peptide of human bone morphogenetic protein-2 in Escherichia coil. Methods: TheDNA fragment encoding the mature peptide of human bone morphogenetic protein-2 (hBMP-2m) was inserted into expression vectorpDH in which foreign gene was controlled by PRPL promoters. E. coli DH5a transformed with recombinant plasmid pDHB2m wasinduced at 42℃to express the target protein. The expressed product was partially purified and refolded, and then implanted intorat thigh muscles to assay its bone inductive activity. Results: After induction, a protein band on SDS-PAGE gel with an apparentmol. wt. of 13kD was observed to anticipate in the strain carrying pDHB2m, but not in the control. The expressed hBMP-2m accounted for 45%-60% of the total bacterial protein. The expressed product existed in a form of inclusion body. After partially purified and refolded, rhBMP-2m could induce the formation of cartilage and bone tissue heterotopically. Conclusion: The maturepeptide of human bone morphogenetic protein-2 has ben successfully expressed in E. coli and the product has ectopic bone inductive activity.

Three-dimensional kagome structures in a PCL/HA-based hydrogel scaffold to lead slow BMP-2 release for effective bone regeneration

Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteoconductivity and osteoinductivity is required for clinical therapy.Recently,the three-dimensional(3D)kagome structure has been shown to be advantageous for bone tissue regeneration due to its mechanical properties.In this study,a polycaprolactone(PCL)kagome-structure scaffold containing a hyaluronic acid(HA)-based hydrogel was fabricated using a 3D printing technique.The retention capacity of the hydrogel in the scaffold was assessed in vivo with a rat calvaria subcutaneous model for 3 weeks,and the results were compared with those obtained with conventional 3D-printed PCL grid-structure scaffolds containing HA-based hydrogel and bulk-type HA-based hydrogel.The retained hydrogel in the kagome-structure scaffold was further evaluated by in vivo imaging system analysis.To further reinforce the osteoinductivity of the kagome-structure scaffold,a PCL kagome-structure scaffold with bone morphogenetic protein-2(BMP-2)containing HA hydrogel was fabricated and implanted in a calvarial defect model of rabbits for 16 weeks.The bone regeneration characteristics were evaluated with hematoxylin and eosin(H&E),Masson’s trichrome staining,and micro-CT image analysis.

Bone morphogenetic protein-7 induced bone marrow stromal cells differentiate into neuron-like cells

Bone morphogenetic protein-7 is widely accepted as an inducer for bone marrow stem cells differentiating into osteoblasts and chondrocytes. Whether bone marrow stromal cells differentiate into neuron-like cells remains unclear. The current study examined the presence of positive cells for intermediate filament protein and microtubule associated protein-2 in the cytoplasm of bone marrow stromal cells induced by bone morphogenetic protein-7 under an inverted microscope, while no expression of glial fibrillary acidic protein was found. Reverse transcription PCR electrophoresis also revealed a positive target band for intermediate filament protein and microtubule-associated protein 2 mRNA. These results confirmed that bone morphogenetic protein-7 induces rat bone marrow stromal cells differentiating into neuron-like cells.

Injectable bioactive polymethyl methacrylate-hydrogel hybrid bone cement loaded with BMP-2 to improve osteogenesis for percutaneous vertebroplasty and kyphoplasty

Poly methyl methacrylate(PMMA)bone cement is used in augmenting and stabilizing fractured vertebral bodies through percutaneous vertebroplasty(PVP)and percutaneous kyphoplasty(PKP).However,applications of PMMA bone cement are limited by the high elasticity modulus of PMMA,its low biodegradability,and its limited ability to regenerate bone.To improve PMMA bio activity and biodegradability and to modify its elasticity modulus,we mixed PMMA bone cement with oxidized hyaluronic acid and carboxymethyl chitosan in situ cross-linking hydrogel loaded with bone morphogenetic protein-2(BMP-2)to achieve novel hybrid cement.These fabric ated PMMA-hydrogel hybrid cements exhibited lower setting temperatures,a lower elasticity modulus,and better biodegradability and biocompatibility than that of pure PMMA cement,while retaining acceptable setting times,mechanical strength,and inj ectability.In addition,we detected release of BMP-2 from the PMMA-hydrogel hybrid cements,significantly enhancing in vitro osteogenesis of bone marrow mesenchymal stem cells by up-regulating the gene expression of Runx2,Coll,and OPN.Use of PMMA-hydrogel hybrid cements loaded with BMP-2 on rabbit femoral condyle bone-defect models revealed their biodegradability and enhanced bone formation.Our study demonstrated the favorable mechanical properties,biocompatibility,and biodegradability of fabricated PMMA-hydrogel hybrid cements loaded with BMP-2,as well as their ability to improve osteogenesis,making them a promising material for use in PKP and PVP.

Synthesis and Characterization of UPPE-PLGA-rhBMP2 Scaffolds for Bone Regeneration

A novel unsaturated polyphosphoester(UPPE) was devised in our previous research,which is a kind of promising scaffold for improving bone regeneration.However,the polymerization process of UPPE scaffolds was unfavorable,which may adversely affect the bioactivity of osteoinductive molecules added if necessary,such as recombinant human bone morphogenetic protein-2(rhBMP2).The purpose of this study was to build a kind of optimal scaffold named UPPE-PLGA-rhBMP2(UPB) and to investigate the bioactivity of rhBMP2 in this scaffold.Furthermore,the cytotoxicity and biocompatibility of UPB scaffold was assessed in vitro.A W1/O/W2 method was used to fabricate PLGA-rhBMP2 microspheres,and then the microspheres were added to UPPE for synthesizing UPB scaffold.The morphological characters of PLGA-rhBMP2 microspheres and UPB scaffolds were observed under the scanning electron microscopy and laser scanning confocal microscopy.The cumulative release of UPB scaffolds was detected by using ELISA.The cytotoxicity and biocompatibility of UPB scaffolds were evaluated through examining the adsorption and apoptosis of bone marrow stromal cells(bMSCs) seeded on the surface of UPB scaffolds.The bioactivity of rhBMP2 in UPB scaffolds was assessed through measuring the alkaline phosphates(ALP) activity in bMSCs seeded.The results showed that UPB scaffolds sequentially exhibited burst and sustained release of rhBMP2.The cytotoxicity was greatly reduced when the scaffolds were immersed in buffer solution for 2 h.bMSCs attached and grew on the surface of soaked UPB scaffolds,exerting well biocompatibility.The ALP activity of bMSCs seeded was significantly enhanced,indicating that the bioactivity of rhBMP2 remained and still took effect after the unfavorable polymerization process of scaffolds.It was concluded that UPB scaffolds have low cytotoxicity,good biocompatibility and preserve bioactivity of rhBMP2.UPB scaffolds are promising in improving bone regeneration.

Bone Regeneration Enhanced by Antigen-Extracted Xenogeneic Cancellous Bone Graft with rhBMP-2 in Rabbits Mandibular Defect Repair

The effects of large piece xenogeneic bone which was separated from healthy pigs as a scaffold on repair of mandibular defect was investigated and the applicability of antigen-extracted xenogeneic cancellous bone (AXCB) soaked with rhBMP-2 in bone defect repair was assessed. Mandibular defects were created in 48 New Zealand Rabbits, and then randomly divided into 4 groups, which was grafted in the mandibular defects with AXCB, AXCB soaked with rhBMP-2, autograft bone, or blank. Equal number of animals from each group was classified into three time points (4, 8, and 12 weeks) after operation for gross pathological observation, hematoxylin and eosin (H & E) staining, radiographic examination, and bone density measurement. H & E staining revealed that the area percentage of bone regeneration in the group of AXCB/rhBMP-2 graft was 27.72 ± 4.68, 53.90 ± 21.92, and 77.35 ± 9.83 when at 4, 8, and 12 weeks, which was better than that of auto bone graft, prompting that the group of AXCB/rhBMP-2 graft had commendable osteogenic effect. And comparing with the AXCB without rhBMP-2, of which the area percentage of bone regeneration was only 14.03 ± 5.02, 28.49 ± 11.35, and 53.90 ± 21.92, the osteogenic effect of AXCB/rhBMP-2 graft was demonstrated to be much better. In the group of AXCB/rhBMP-2 graft, the area percentage of bone regeneration increased, and the implanted materials were gradually degraded and replaced by autogenous bone regeneration over time. We concluded that antigen-extracted xenogeneic cancellous bone (AXCB) graft soaked with rhBMP-2 had shown excellent osteogenic effect in repair of bone defects, with good biocompability.

Three-dimensional bioprinting of multicell-laden scaffolds containing bone morphogenic protein-4 for promoting M2 macrophage polarization and accelerating bone defect repair in diabetes mellitus

Critical-sized bone defect repair in patients with diabetes mellitus remains a challenge in clinical treatment because of dysfunction of macrophage polarization and the inflammatory microenvironment in the bone defect region.Three-dimensional(3D)bioprinted scaffolds loaded with live cells and bioactive factors can improve cell viability and the inflammatory microenvironment and further accelerating bone repair.Here,we used modified bioinks comprising gelatin,gelatin methacryloyl(GelMA),and 4-arm poly(ethylene glycol)acrylate(PEG)to fabricate 3D bioprinted scaffolds containing BMSCs,RAW264.7 macrophages,and BMP-4-loaded mesoporous silica nanoparticles(MSNs).Addition of MSNs effectively improved the mechanical strength of GelMA/gelatin/PEG scaffolds.Moreover,MSNs sustainably released BMP-4 for long-term effectiveness.In 3D bioprinted scaffolds,BMP-4 promoted the polarization of RAW264.7 to M2 macrophages,which secrete anti-inflammatory factors and thereby reduce the levels of pro-inflammatory factors.BMP-4 released from MSNs and BMP-2 secreted from M2 macrophages collectively stimulated the osteogenic differentiation of BMSCs in the 3D bioprinted scaffolds.Furthermore,in calvarial critical-size defect models of diabetic rats,3D bioprinted scaffolds loaded with MSNs/BMP-4 induced M2 macrophage polarization and improved the inflammatory microenvironment.And 3D bioprinted scaffolds with MSNs/BMP-4,BMSCs,and RAW264.7 cells significantly accelerated bone repair.In conclusion,our results indicated that implanting 3D bioprinted scaffolds containing MSNs/BMP-4,BMSCs,and RAW264.7 cells in bone defects may be an effective method for improving diabetic bone repair,owing to the direct effects of BMP-4 on promoting osteogenesis of BMSCs and regulating M2 type macrophage polarization to improve the inflammatory microenvironment and secrete BMP-2.

毛细管电泳免疫化学发光检测鼠血管平滑肌细胞中zmol骨形成蛋白-2

In this study, a capillary electrophoresis immunoassay(CEIA) method based on the enhanced chemiluminescence(CL) detection was developed. A horseradish peroxidase(HRP) label catalyzing the luminol/H 2O 2/p-iodophenol(PIP) reaction was performed, and the HRP was detected with detection limit(S/N=3) of 4.4 pmol/L(53 zmol), which is one of the highest sensitivity of HRP reported yet. The HRP was linked to bone morphogenic protein-2(BMP-2) in rat vascular smooth muscle(VSM) cells in noncompetitive format and first detected by CL. HRP-Ab 2-mAb-BMP-2 complexes were baseline separated from free HRP label in 3 min. The detection limit(S/N=3) of BMP-2 is 6.2 pmol/L(75 zmol). This technique has been applied to arteriosclerosis pathology research. The change of BMP-2 contentin VSM cells which were stimulated by angiotensin Ⅱ(AgⅡ) for different hours was investigated in the concentration range of 1.0-10.0 pmol/L. The results are in accord with that obtained by common used Pathology image analysis system.