BACKGROUND A major problem in the healing of bone defects is insufficient or absent blood supply within the defect.To overcome this challenging problem,a plethora of approaches within bone tissue engineering have been...BACKGROUND A major problem in the healing of bone defects is insufficient or absent blood supply within the defect.To overcome this challenging problem,a plethora of approaches within bone tissue engineering have been developed recently.Bearing in mind that the interplay of various diffusible factors released by endothelial cells(ECs)and osteoblasts(OBs)have a pivotal role in bone growth and regeneration and that adjacent ECs and OBs also communicate directly through gap junctions,we set the focus on the simultaneous application of these cell types together with platelet-rich plasma(PRP)as a growth factor reservoir within ectopic bone tissue engineering constructs.AIM To vascularize and examine osteogenesis in bone tissue engineering constructs enriched with PRP and adipose-derived stem cells(ASCs)induced into ECs and OBs.METHODS ASCs isolated from adipose tissue,induced in vitro into ECs,OBs or just expanded were used for implant construction as followed:BPEO,endothelial and osteogenic differentiated ASCs with PRP and bone mineral matrix;BPUI,uninduced ASCs with PRP and bone mineral matrix;BC(control),only bone mineral matrix.At 1,2,4 and 8 wk after subcutaneous implantation in mice,implants were extracted and endothelial-related and bone-related gene expression were analyzed,while histological analyses were performed after 2 and 8 wk.RESULTS The percentage of vascularization was significantly higher in BC compared to BPUI and BPEO constructs 2 and 8 wk after implantation.BC had the lowest endothelial-related gene expression,weaker osteocalcin immunoexpression and Spp1 expression compared to BPUI and BPEO.Endothelial-related gene expression and osteocalcin immunoexpression were higher in BPUI compared to BC and BPEO.BPEO had a higher percentage of vascularization compared to BPUI and the highest CD31 immunoexpression among examined constructs.Except Vwf,endothelial-related gene expression in BPEO had a later onset and was upregulated and well-balanced during in vivo incubation that induced late onset of Spp1 expression and pronounced osteocalcin immunoexpression at 2 and 8 wk.Tissue regression was noticed in BPEO constructs after 8 wk.CONCLUSION Ectopically implanted BPEO constructs had a favorable impact on vascularization and osteogenesis,but tissue regression imposed the need for discovering a more optimal EC/OB ratio prior to considerations for clinical applications.展开更多
Covalent binding between bioactive substances and materials in different ways can significantly improve the bone inductivity and biological activity of bone repair materials.However,there is a lack of systematic under...Covalent binding between bioactive substances and materials in different ways can significantly improve the bone inductivity and biological activity of bone repair materials.However,there is a lack of systematic understanding of how these binding modes affect biological activities of the active substances.In this study,four kinds of functionalized Multi-walled carbon nanotubes(MWCNTs)were prepared,ensuring the same grafting rate of different functional groups.Subsequently,two kinds of osteogenic-related peptides,bone morphogenetic protein-2 mimicking peptides and osteogenic growth mimicking peptides,were covalently bound to functionalized MWCNTs,ensuring the same molar mass of peptides bound to different functionalized MWCNTs in this process.Then the same amount of functionalized MWC-NTs/Peptides composites were introduced into the scaffolds,and through the ectopic osteogenesis model in rats and calvarial defect model in rabbits,ectopic osteogenesis and bone repair ability of the composites were analyzed.Furthermore,the effects of different covalent binding modes on peptide-induced osteogenesis and bone repair were studied.The results showed that the negative influencing trend of different covalent binding modes of osteogenic-related peptides with artificial carriers on their biological activities was in the order as follows:amide binding(carboxyl)>silane coupling>dopamine bind-ing>amide binding(amino),whose mechanism might be mainly that the covalent binding of peptides with different functional groups resulted in different charges.We believe that the results of this study have important guiding significance for the research and development of bone repair materials covalently bound with bioactive substances.展开更多
基金Supported by Ministry of Education,Science and Technological Development of the Republic of Serbia,No.III 41017.
文摘BACKGROUND A major problem in the healing of bone defects is insufficient or absent blood supply within the defect.To overcome this challenging problem,a plethora of approaches within bone tissue engineering have been developed recently.Bearing in mind that the interplay of various diffusible factors released by endothelial cells(ECs)and osteoblasts(OBs)have a pivotal role in bone growth and regeneration and that adjacent ECs and OBs also communicate directly through gap junctions,we set the focus on the simultaneous application of these cell types together with platelet-rich plasma(PRP)as a growth factor reservoir within ectopic bone tissue engineering constructs.AIM To vascularize and examine osteogenesis in bone tissue engineering constructs enriched with PRP and adipose-derived stem cells(ASCs)induced into ECs and OBs.METHODS ASCs isolated from adipose tissue,induced in vitro into ECs,OBs or just expanded were used for implant construction as followed:BPEO,endothelial and osteogenic differentiated ASCs with PRP and bone mineral matrix;BPUI,uninduced ASCs with PRP and bone mineral matrix;BC(control),only bone mineral matrix.At 1,2,4 and 8 wk after subcutaneous implantation in mice,implants were extracted and endothelial-related and bone-related gene expression were analyzed,while histological analyses were performed after 2 and 8 wk.RESULTS The percentage of vascularization was significantly higher in BC compared to BPUI and BPEO constructs 2 and 8 wk after implantation.BC had the lowest endothelial-related gene expression,weaker osteocalcin immunoexpression and Spp1 expression compared to BPUI and BPEO.Endothelial-related gene expression and osteocalcin immunoexpression were higher in BPUI compared to BC and BPEO.BPEO had a higher percentage of vascularization compared to BPUI and the highest CD31 immunoexpression among examined constructs.Except Vwf,endothelial-related gene expression in BPEO had a later onset and was upregulated and well-balanced during in vivo incubation that induced late onset of Spp1 expression and pronounced osteocalcin immunoexpression at 2 and 8 wk.Tissue regression was noticed in BPEO constructs after 8 wk.CONCLUSION Ectopically implanted BPEO constructs had a favorable impact on vascularization and osteogenesis,but tissue regression imposed the need for discovering a more optimal EC/OB ratio prior to considerations for clinical applications.
基金support from the National Natural Science Foundation of China(Nos.32171345 and 31771042)the Hebei Provincial Natural Science Foundation of China(No.C2022104003)+2 种基金the Fok Ying Tung Education Foundation(No.141039)the Fund of Key Laboratory of Advanced Materials of Ministry of Educationthe International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology of China,and the 111 Project(No.B13003).
文摘Covalent binding between bioactive substances and materials in different ways can significantly improve the bone inductivity and biological activity of bone repair materials.However,there is a lack of systematic understanding of how these binding modes affect biological activities of the active substances.In this study,four kinds of functionalized Multi-walled carbon nanotubes(MWCNTs)were prepared,ensuring the same grafting rate of different functional groups.Subsequently,two kinds of osteogenic-related peptides,bone morphogenetic protein-2 mimicking peptides and osteogenic growth mimicking peptides,were covalently bound to functionalized MWCNTs,ensuring the same molar mass of peptides bound to different functionalized MWCNTs in this process.Then the same amount of functionalized MWC-NTs/Peptides composites were introduced into the scaffolds,and through the ectopic osteogenesis model in rats and calvarial defect model in rabbits,ectopic osteogenesis and bone repair ability of the composites were analyzed.Furthermore,the effects of different covalent binding modes on peptide-induced osteogenesis and bone repair were studied.The results showed that the negative influencing trend of different covalent binding modes of osteogenic-related peptides with artificial carriers on their biological activities was in the order as follows:amide binding(carboxyl)>silane coupling>dopamine bind-ing>amide binding(amino),whose mechanism might be mainly that the covalent binding of peptides with different functional groups resulted in different charges.We believe that the results of this study have important guiding significance for the research and development of bone repair materials covalently bound with bioactive substances.
