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.

Heterotopic ossification after the use of recombinant human bone morphogenetic protein-7

AIM To present the incidence of heterotopic ossification after the use of recombinant human bone morphogenetic protein-7(rhB MP-7) for the treatment of nonunions.METHODS Bone morphogenetic proteins(BMPs) promote bone formation by auto-induction. Recombinant human BMP-7 in combination with bone grafts was used in 84 patients for the treatment of long bone nonunions. All patients were evaluated radiographicaly for the development of heterotopic ossification during the standard assessment for the nonunion healing. In all patients(80.9%) with radiographic signs of heterotopic ossification, a CT scan was performed. Nonunion site palpation and ROM evaluation of the adjacent jointswere also carried out. Factors related to the patient(age, gender), the nonunion(location, size, chronicity, number of previous procedures, infection, surrounding tissues condition) and the surgical procedure(graft and fixation type, amount of rhB MP-7) were correlated with the development of heterotopic ossification and statistical analysis with Pearsons χ~2 test was performed.RESULTS Eighty point nine percent of the nonunions treated with rh BMP-7, healed with no need for further procedures. Heterotopic bone formation occurred in 15 of 84 patients(17.8%) and it was apparent in the routine radiologi-cal evaluation of the nonunion site, in a mean time of 5.5 mo after the rh BMP-7 application(range 3-12). The heterotopic ossification was located at the femur in 8 cases, at the tibia in 6, and at the humerus in οne patient. In 4 patients a palpable mass was present and only in one patient, with a para-articular knee nonunion treated with rhB MP-7, the size of heterotopic ossification affected the knee range of motion. All the patients with heterotopic ossification were male. Statistical analysis proved that patient's gender was the only important factor for the development of heterotopic ossification(P = 0.007). CONCLUSION Heterotopic ossification after the use of rh BMP-7 in nonunions was common but it did not compromise the final clinical outcome in most cases, and affected only male patients.

Recombinant human bone morphogenetic protein-7 expressed from CHO cells possessing the activity of bone-induced in vitro

Objective To express the recombinant human bone morphogenetic protein-7 (rhBMP-7) in Chinese hamster ovary (CHO) cells and to establish the in vitro biological activity assay of rhBMP-7. Methods Human BMP-7 cDNA was subcloned into pcDNA3.1 mammalian expression vector and transfected to CHO cells by using the lipofectin transfection method. BMP-7 expression cell culture supernatants were harvested and purified for target protein. To analyze the bioactivity of the secreted rhBMP-7, a novel in vitro assay was established by measuring its alkaline phosphatase (ALP) stimulating of osteoblast cell line, W-20-17. Results BMP-7 stably expressing cell clone was selected, which secreted mature disulfide-linked homodimer form of hBMP-7 and had an apparent molecular weight of 36kDa. rhBMP-7 with >95% purity was obtained using 3 step chromatography method. Bioactivity assay showed that the purified protein specifically stimulated W-20-17 cell producing ALP, with a 4-fold increase of ALP activity at 100ng/ml or more, and the EC50 of 15.6ng/ml. Conclusion Purified rhBMP-7 from this CHO expression system has significant biological activity in induction of osteoblast phenotype, which demonstrates potential bone regeneration activity.

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.

CORAL AS A CARRIER FOR RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN-2

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EFFECTS OF TRANSFORMING GROWTH FACTOR β AND RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN 2 ON HUMAN PERIODONTAL LIGAMENT FIBROBLASTS

Objective To evaluate the effects of transforming growth factor β(TGF-β) and recombinant human bone morphogenetic protein 2 (rhBMP2) on human periodontal ligament fibroblasts (HPDLFs). Methods HPDLFs were done primary culture to detect the distinct concentrations of TGF-P and rhBMF2 on its proliferation, alkaline phosphatase (ALP) activity, osteocalcin (OC) synthesis and formation of the minerali-zed nodules, respectively. Results TGF-β (5～100ng/ml) significantly stimulated the proliferation of HPDLFs. The ALP activity of HPDLFs was evaluated evidently by 5ng/ml TGF-β. TGF-β( 0. 5 ～ 100ng/ml) had no effects on OC synthesis and formation of the mineralized nodules of HPDLFs. rhBMP2 (0. 25～2mg/ ml) had no remarkable effect on the proliferation of HPDLFs. The ALP activity, OC synthesis and forma-tion of the mineralized nodules of HPDLFs were significantly stimulated by 0. 5～ 2mg /ml rhBMP2. Conclusion The effects of TGF-β and rhBMP2 on HPDLFs are dose-dependent. TGF-P can stimulate HPDLFs to express the early marker of osteoblastic phenotype, and it lacks the ability to promote maturation of the osteogenic phenotype. rhBMP2 can not only stimulate the expression but also promote the maturation of osteoblas-tic phenotype of HPDLFs.

Construction of Adeno-associated Virus System for Human Bone Morphogenetic Protein 7 Gene

To construct the recombinant adeno-associated virus （rAAV） vector with human bone morphogenetic protein 7 （BMP7） and observe the BMP7 mRNA expression in vitro, BMP7 CDS sequence was cloned into expression plasmid pAAV-MCS of AAV Helper Free System. The recombinant plasmid was identified with enzyme digestion and sequencing. The recombinant plasmid, pAAV-RC, pHelper were co-transfected into AAV-293 cells according to the calcium phosphate-based protocol. The viral stock was collected by 4 rounds of freeze/thaw. After purified and concentrated, the recombinant virus titer was determined by dot-blot assay. HEK293 cells were transfected with the recombinant virus at different MOI, and the expression of BMP7 mRNA was detected by RT-PCR. The results showed rAAV-BMP7 was constructed and packaged successfully. The physical particle titer was 2.5×10^11 vector genomes/mL. There was different expression level of BMP7 mRNA after transfecton. These data suggested that recombinant AAV mediated a stable expression of hBMP7 mRNA in 293 cells. The AAV production method may pave the way of an effective strategy for the jaw bone defection around dental implants.

Inductive effect of bovinc bone morphogenetic protein on human dental pulp tissue in vitro

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SPECIFIC BINDING OF HUMAN BONEMORPHOGENETIC PROTEIN （2A） WITH MOUSEOSTEOBLASTIC CELLS

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Human bone morphogenetic protein-2 gene transfer induces human mesenchymal stem cell proliferation and differentiation in vitro

Objective: To identify eukaryotic expression vector of human bone morphogenetic protein 2 pcDNA3/BMP2, verify its expression in transfected human mesenchymal stem cells (hMSCs) and the effect on hMSCs differentiation. Methods: The BMP2 gene was cloned into a eukaryotic expression vector pcDNA3. Transfected the recombinant into hMSCs by liposome. Immunnohistochemistry and in situ hybridization methods were used to identify the expression of BMP2 mRNA and protein; ALP and Von Kossa stains were performed to identify the BMP2 gene differentiated effect on the hMSCs. Results: The pcDNA3/BMP2 fragments were as large as theory. BMP2 mRNA and protein were expressed and synthesized both in 48 h and 4 weeks after transfection, the ALP and Ca deposit exhibition, which marked the osteogenic lineage of hMSCs, were enhanced and sped. Conclusion: Transfection of pcDNA3/BMP2 is able to provide transient and persistent expression in hMSCs, and promote the MSCs differentiation to osteogenic lineage.

Bone morphogenetic protein-4 affects both trophoblast and non-trophoblast lineage-associated gene expression in human embryonic stem cells

Human embryonic stem cells (hESC) can be induced to differentiate to trophoblast by bone morphogenetic proteins (BMPs) and by aggregation to form embryoid bodies (EB), but there are many differences and controversies regarding the nature of the differentiated cells. Our goals herein were to determine if BG02 cells form trophoblast-like cells (a) in the presence of BMP4-plus-basic fibroblast growth factor (FGF-2) and (b) upon EB formation, and (c) whether the BMP4 antagonist noggin elicits direct effects on gene expression and hormone production in the cells. Transcriptome profiling of hESC incubated with BMP4/FGF-2 showed a down-regulation of pluripotency-associated genes, an up-regulation of trophoblast-associated genes, and either a down-regulation or no change in gene expression for many markers of the three embryonic germ layers. Yet, there was up-regulation of several genes associated with mesoderm, ectoderm, and endoderm, strongly suggesting that differentiation to trophoblast-like cells under the conditions used does not yield a homogeneous cell type. Several genes, heretofore unreported, were identified that are altered in hESC in response to BMP4-mediated differentiation. The production of human chorionic gonadotropin (hCG), progesterone, and estradiol in the differentiated cells confirmed that trophoblast-like cells were obtained. Gene expression by EB was characterized by an up-regulation of a number of genes associated with trophoblast, ectoderm, endoderm, and mesoderm, and the production of hCG and progesterone confirmed that trophoblast-like cells were formed. These results suggest that, in the presence of FGF-2, BG02 cells respond to BMP4 to yield trophoblast-like cells, which are also obtained upon EB formation. Thus, BMP4-mediated differentiation of hESC represents a viable cell system for studying early developmental events post-implantation;however, up-regulation of non-trophoblast genes suggests a somewhat diverse response to BMP4/FGF-2. Noggin altered the transcription of a limited number of genes but, not surprisingly, did not lead to secretion of hormones.

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.

Construction of bicistronic green fluorescent protein labeled pSELECT GFPzeo human bone morphogenetic protein 2 eukaryotic expression vector

Objective To construct green fluorescent protein (GFP)-labeled pSELECT-GFP zeohBMP2 eukaryotic expression vector.Methods The encoding fragment of hBMP2 gene was obtained from a recombinant plasmid pcDNA3.1/CT-hBMP2 by using polymerase

BMPRⅡ^(+)neural precursor cells isolated and characterized from organotypic neurospheres:an in vitro model of human fetal spinal cord development

Roof plate secretion of bone morphogenetic proteins(BMPs)directs the cellular fate of sensory neurons during spinal cord development,including the formation of the ascending sensory columns,though their biology is not well understood.Type-ⅡBMP receptor(BMPRⅡ),the cognate receptor,is expressed by neural precursor cells during embryogenesis;however,an in vitro method of enriching BMPRⅡ^(+)human neural precursor cells(hNPCs)from the fetal spinal cord is absent.Immunofluorescence was undertaken on intact second-trimester human fetal spinal cord using antibodies to BMPRⅡand leukemia inhibitory factor(LIF).Regions of highest BMPRⅡ^(+)immunofluorescence localized to sensory columns.Parenchymal and meningeal-associated BMPRⅡ^(+)vascular cells were identified in both intact fetal spinal cord and cortex by co-positivity with vascular lineage markers,CD34/CD39.LIF immunostaining identified a population of somas concentrated in dorsal and ventral horn interneurons,mirroring the expression of LIF receptor/CD118.A combination of LIF supplementation and high-density culture maintained culture growth beyond 10 passages,while synergistically increasing the proportion of neurospheres with a stratified,cytoarchitecture.These neurospheres were characterized by BMPRⅡ^(+)/MAP2ab^(+/–)/βⅢ-tubulin^(+)/nestin^(–)/vimentin^(–)/GFAP^(–)/NeuN^(–)surface hNPCs surrounding a heterogeneous core ofβⅢ-tubulin^(+)/nestin^(+)/vimentin^(+)/GFAP^(+)/MAP2ab^(–)/NeuN^(–)multipotent precursors.Dissociated cultures from tripotential neurospheres contained neuronal(βⅢ-tubulin^(+)),astrocytic(GFAP+),and oligodendrocytic(O4+)lineage cells.Fluorescence-activated cell sorting-sorted BMPRⅡ^(+)hNPCs were MAP2ab^(+/–)/βⅢ-tubulin^(+)/GFAP^(–)/O4^(–)in culture.This is the first isolation of BMPRⅡ^(+)hNPCs identified and characterized in human fetal spinal cords.Our data show that LIF combines synergistically with high-density reaggregate cultures to support the organotypic reorganization of neurospheres,characterized by surface BMPRⅡ^(+)hNPCs.Our study has provided a new methodology for an in vitro model capable of amplifying human fetal spinal cord cell numbers for>10 passages.Investigations of the role BMPRⅡplays in spinal cord development have primarily relied upon mouse and rat models,with interpolations to human development being derived through inference.Because of significant species differences between murine biology and human,including anatomical dissimilarities in central nervous system(CNS)structure,the findings made in murine models cannot be presumed to apply to human spinal cord development.For these reasons,our human in vitro model offers a novel tool to better understand neurodevelopmental pathways,including BMP signaling,as well as spinal cord injury research and testing drug therapies.

病毒性脑膜炎患儿血清和脑脊液中IP-10和TNF-α的表达情况及临床意义

目的探讨肿瘤坏死因子-α(TNF-α)、重组人干扰素诱导蛋白-10(IP-10)在病毒性脑膜炎患儿血清和脑脊液中的表达情况及临床意义。方法选取2019年7月至2020年12月在邢台市人民医院儿三科因急性中枢神经系统感染住院治疗的100例患儿作为研究对象。以脑膜炎感染类型分为病毒性脑膜炎组(52例)、化脓性脑膜炎组(34例)、结核性脑膜炎组(14例)。采用酶联免疫吸附试验检测所有研究对象血清及脑脊液TNF-α、IP-10水平。采用Pearson相关分析病毒性脑膜炎患儿血清及脑脊液TNF-α水平与IP-10水平的相关性。绘制受试者工作特征(ROC)曲线评估血清及脑脊液TNF-α和IP-10对病毒性脑膜炎的诊断价值。结果结核性脑膜炎组血清及脑脊液TNF-α和IP-10水平均高于化脓性脑膜炎组与病毒性脑膜炎组,且化脓性脑膜炎组均高于病毒性脑膜炎组,差异均有统计学意义(P<0.05)。病毒性脑膜炎患儿血清中IP-10水平与TNF-α水平呈明显正相关(r=0.313,P<0.05)。脑脊液中TNF-α水平与IP-10水平呈明显正相关(r=0.455,P<0.05)。ROC曲线分析结果显示,血清IP-10、TNF-α单独诊断病毒性脑膜炎的曲线下面积(AUC)分别为0.887、0.898,均小于2项指标联合诊断病毒性脑膜炎的0.958(Z=2.010、2.048,P<0.05);脑脊液IP-10、TNF-α单独诊断病毒性脑膜炎的AUC分别为0.926、0.908,均小于2项指标联合诊断病毒性脑膜炎的0.964(Z=2.208、2.260,P<0.05)。结论血清及脑脊液TNF-α和IP-10水平在病毒性脑膜炎患儿中明显降低,2项指标联合检测对病毒性脑膜炎的诊断具有重要临床价值。

骨形态发生蛋白10及其突变体在CHO细胞中的表达

为了解决骨形态发生蛋白10(bone morphogenetic protein 10,BMP10)前体蛋白proBMP10在中国仓鼠卵巢(CHO)细胞中由于Furin导致的表达产物不均一问题,构建了proBMP10在Furin酶切识别位点处的突变体proBMP10-1(R313K)和proBMP10-2(R316K),并分别将目的基因定点整合进CHO-K1-BAK-/BAX-基因组,成功构建了稳定表达目标蛋白质的重组CHO细胞株。结果表明,proBMP10-2 (R316K)不再被Furin切割,且具有生物活性,而proBMP10-1(R313K)仍然会被Furin切割。

Diagnostic Value of GDF10 for the Tumorigenesis and Immune Infiltration in Lung Squamous Cell Carcinoma

Objective:Lung squamous cell carcinoma(LUSC)is associated with a low survival rate.Evidence suggests that bone morphogenetic proteins(BMPs)and their receptors(BMPRs)play crucial roles in tumorigenesis and progression.However,a comprehensive analysis of their role in LUSC is lacking.Our study aimed to explore the relationship between BMPs/BMPRs expression levels and the tumorigenesis and prognosis of LUSC.Methods:The“R/Limma”package was utilized to analyze the differential expression characteristics of BMPs/BMPRs in LUSC,using data from TCGA,GTEx,and GEO databases.Concurrently,the“survminer”packages were employed to investigate their prognostic value and correlation with clinical features in LUSC.The core gene associated with LUSC progression was further explored through weighted gene correlation network analysis(WGCNA).LASSO analysis was conducted to construct a prognostic risk model for LUSC.Clinical specimens were examined by immunohistochemical analysis to confirm the diagnostic value in LUSC.Furthermore,based on the tumor immune estimation resource database and tumor-immune system interaction database,the role of the core gene in the tumor microenvironment of LUSC was explored.Results:GDF10 had a significant correlation only with the pathological T stage of LUSC,and the protein expression level of GDF10 decreased with the tumorigenesis of LUSC.A prognostic risk model was constructed with GDF10 as the core gene and 5 hub genes(HRASLS,HIST1H2BH,FLRT3,CHEK2,and ALPL)for LUSC.GDF10 showed a significant positive correlation with immune cell infiltration and immune checkpoint expression.Conclusion:GDF10 might serve as a diagnostic biomarker reflecting the tumorigenesis of LUSC and regulating the tumor immune microenvironment to guide more effective treatment for LUSC.

A型肉毒毒素防治额部外伤瘢痕的美学效果及对血清TGF-β_(1)、BMP-7水平的影响

目的:探讨A型肉毒毒素防治额部外伤瘢痕的美学效果及对血清TGF-β_(1)、BMP-7水平的影响。方法:选取2020年7月-2022年10月笔者医院收治的84例额部外伤患者为研究对象,按随机数字表法分为观察组和对照组,各42例。对照组采用清创美容缝合联合外用硅凝胶制剂防治瘢痕;观察组采用美容缝合拆线后伤口两侧注射A型肉毒毒素防治瘢痕。拆线后3个月,统计比较两组瘢痕临床防治有效率、瘢痕评分[温哥华瘢痕量表(Vancouver scar scale,VSS)]、瘢痕疼痛或瘙痒程度评分[视觉模拟评分法(Visual analogue scale,VAS)]、患者满意度、血清转化生长因子β_(1)(Transforming growth factor-β_(1),TGF-β_(1))和骨成型蛋白7(Recombinant bone morphogenetic protein 7,BMP-7)水平及不良反应。结果:观察组VSS评分、瘢痕疼痛或瘙痒程度VAS评分低于对照组(P<0.05);观察组瘢痕临床防治有效率为90.47%,高于对照组的69.04%(P<0.05);观察组患者满意度高于对照组(P<0.05);观察组TGF-β_(1)水平低于对照组,BMP-7水平高于对照组(P<0.05);两组均未发生严重不良反应。结论:额部软组织外伤患者美容缝合拆线后伤口两侧注射A型肉毒毒素可抑制瘢痕形成,有效提升瘢痕防治有效率及患者满意度,其临床效果可能与调控血清TGF-β_(1)和BMP-7水平有关,且安全性较高,具有一定的临床应用价值。

Reconstruction of orbital defect in rabbits with composite of calcium phosphate cement and recombinant human bone morphogenetic protein-2

Background Calcium phosphate cement （CPC） is a biocompatible and osteoconductive bone substitute, and recombinant human bone morphogenetic protein-2 （rhBMP-2） has strong osteoinductibility, therefore we developed a composite bone substitute with CPC and rhBMP-2 and evaluate its reconstruction effect in rabbit orbital defect.Methods Thirty-six rabbits were randomly divided into two groups and a 5 mmx5 mmx2 mm bone defect in the infraorbital rim was induced by surgery in each orbit （72 orbits in all）. The orbital defects were treated with pure CPC or composite of CPC and rhBMP-2. The osteogenesis ability of different bone substitute was evaluated by gross observation, histological examination, histomorphometrical evaluation, compressive load-to-failure testing, and scanning electron microscope （SEM）.Results Gross observation showed that both bone substitutes were safe and effective for reconstruction of orbital defect. However, histological examination, histomorphometrical evaluation and SEM showed that CPC/rhBMP-2 group had faster speed in new bone formation and degradation of substitute material than CPC group. Compressive load-to-failure testing showed that CPC/rhBMP-2 group had stronger compressive strength than CPC group at every stage with significant difference （P ＜0.05）.Conclusion Composite of CPC/rhBMP-2 is an ideal bioactive material for repairing orbital defect, with good osteoconductibility and osteoinductibility.