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
The aim of the present study was the in vitro and in vivo analysis of a bi-layered 3D-printed scaffold combining a PLA layer and a biphasic PLA/bioglass G5 layer for regeneration of osteochondral defects in vivo Focus...The aim of the present study was the in vitro and in vivo analysis of a bi-layered 3D-printed scaffold combining a PLA layer and a biphasic PLA/bioglass G5 layer for regeneration of osteochondral defects in vivo Focus of the in vitro analysis was on the(molecular)weight loss and the morphological and mechanical variations after immersion in SBF.The in vivo study focused on analysis of the tissue reactions and differences in the implant bed vascularization using an established subcutaneous implantation model in CD-1 mice and established histological and histomorphometrical methods.Both scaffold parts kept their structural integrity,while changes in morphology were observed,especially for the PLA/G5 scaffold.Mechanical properties decreased with progressive degradation,while the PLA/G5 scaffolds presented higher compressive modulus than PLA scaffolds.The tissue reaction to PLA included low numbers of BMGCs and minimal vascularization of its implant beds,while the addition of G5 lead to higher numbers of BMGCs and a higher implant bed vascularization.Analysis revealed that the use of a bi-layered scaffold shows the ability to observe distinct in vivo response despite the physical proximity of PLA and PLA/G5 layers.Altogether,the results showed that the addition of G5 enables to reduce scaffold weight loss and to increase mechanical strength.Furthermore,the addition of G5 lead to a higher vascularization of the implant bed required as basis for bone tissue regeneration mediated by higher numbers of BMGCs,while within the PLA parts a significantly lower vascularization was found optimally for chondral regeneration.Thus,this data show that the analyzed bi-layered scaffold may serve as an ideal basis for the regeneration of osteochondral tissue defects.Additionally,the results show that it might be able to reduce the number of experimental animals required as it may be possible to analyze the tissue response to more than one implant in one experimental animal.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We thank the Spanish MINECO for supporting the project MAT2012-38793 and for funding MN through the Ramon y Cajal program and TS through the“Personal Tecnico de Apoyo”subprogram.
文摘The aim of the present study was the in vitro and in vivo analysis of a bi-layered 3D-printed scaffold combining a PLA layer and a biphasic PLA/bioglass G5 layer for regeneration of osteochondral defects in vivo Focus of the in vitro analysis was on the(molecular)weight loss and the morphological and mechanical variations after immersion in SBF.The in vivo study focused on analysis of the tissue reactions and differences in the implant bed vascularization using an established subcutaneous implantation model in CD-1 mice and established histological and histomorphometrical methods.Both scaffold parts kept their structural integrity,while changes in morphology were observed,especially for the PLA/G5 scaffold.Mechanical properties decreased with progressive degradation,while the PLA/G5 scaffolds presented higher compressive modulus than PLA scaffolds.The tissue reaction to PLA included low numbers of BMGCs and minimal vascularization of its implant beds,while the addition of G5 lead to higher numbers of BMGCs and a higher implant bed vascularization.Analysis revealed that the use of a bi-layered scaffold shows the ability to observe distinct in vivo response despite the physical proximity of PLA and PLA/G5 layers.Altogether,the results showed that the addition of G5 enables to reduce scaffold weight loss and to increase mechanical strength.Furthermore,the addition of G5 lead to a higher vascularization of the implant bed required as basis for bone tissue regeneration mediated by higher numbers of BMGCs,while within the PLA parts a significantly lower vascularization was found optimally for chondral regeneration.Thus,this data show that the analyzed bi-layered scaffold may serve as an ideal basis for the regeneration of osteochondral tissue defects.Additionally,the results show that it might be able to reduce the number of experimental animals required as it may be possible to analyze the tissue response to more than one implant in one experimental animal.
