Intervertebral disc regeneration field is rapidly growing since disc disorders represent a major health problem in industrialized countries with very few possible treatments.Indeed, current available therapies are sym...Intervertebral disc regeneration field is rapidly growing since disc disorders represent a major health problem in industrialized countries with very few possible treatments.Indeed, current available therapies are symptomatic, and surgical procedures consist in disc removal and spinal fusion, which is not immune to regardable concerns about possible comorbidities, cost-effectiveness, secondary risks and long-lasting outcomes. This review paper aims to share recent advances in stem cell therapy for the treatment of intervertebral disc degeneration. In literature the potential use of different adult stem cells for intervertebral disc regeneration has already been reported. Bone marrow mesenchymal stromal/stem cells, adipose tissue derived stem cells, synovial stem cells, muscle-derived stem cells, olfactory neural stem cells, induced pluripotent stem cells, hematopoietic stem cells, disc stem cells, and embryonic stem cells have been studied for this purpose either in vitro or in vivo. Moreover, several engineered carriers(e.g., hydrogels), characterized by full biocompatibility and prompt biodegradation, have been designed and combined with different stem cell types in order to optimize the local and controlled delivery of cellular substrates in situ. The paper overviews the literature discussing the current status of our knowledge of the different stem cells types used as a cell-based therapy for disc regeneration.展开更多
Intervertebral disc(IVD)degeneration is a leading cause of back pain and precursor to more severe conditions,including disc herniation and spinal stenosis.While traditional growth factor therapies(e.g.,TGFβ)are effec...Intervertebral disc(IVD)degeneration is a leading cause of back pain and precursor to more severe conditions,including disc herniation and spinal stenosis.While traditional growth factor therapies(e.g.,TGFβ)are effective at transiently reversing degenerated disc by stimulation of matrix synthesis,it is increasingly accepted that bioscaffolds are required for sustained,complete IVD regeneration.Current scaffolds(e.g.,metal/polymer composites,non-mammalian biopolymers)can be improved in one or more IVD regeneration demands:biodegradability,noninvasive injection,recapitulated healthy IVD biomechanics,predictable crosslinking,and matrix repair induction.To meet these demands,tetrazine-norbornene bioorthogonal ligation was combined with gelatin to create an injectable bioorthogonal hydrogel(BIOGEL).The liquid hydrogel precursors remain free-flowing across a wide range of temperatures and crosslink into a robust hydrogel after 5-10 min,allowing a human operator to easily inject the therapeutic constructs into degenerated IVD.Moreover,BIOGEL encapsulation of TGFβpotentiated histological repair(e.g.,tissue architecture and matrix synthesis)and functional recovery(e.g.,high water retention by promoting the matrix synthesis and reduced pain)in an in vivo rat IVD degeneration/nucleotomy model.This BIOGEL procedure readily integrates into existing nucleotomy procedures,indicating that clinical adoption should proceed with minimal difficulty.Since bioorthogonal crosslinking is essentially non-reactive towards biomolecules,our developed material platform can be extended to other payloads and degenerative injuries.展开更多
Background Injectable three-dimensional （3D） scaffolds have the advantages of fluidity and moldability to fill irregularshaped defects,simple incorporation of bioactive factors,and limited surgical invasiveness.Adip...Background Injectable three-dimensional （3D） scaffolds have the advantages of fluidity and moldability to fill irregularshaped defects,simple incorporation of bioactive factors,and limited surgical invasiveness.Adipose-derived stem cells （ADSCs） are multipotent and can be differentiated toward nucleus pulposus （NP）-Iike cells.A hypoxic environment may be important for differentiation to NP-like cells because the intervertebral disc is an avascular tissue.Hence,we investigated the induction effects of hypoxia and an injectable 3D chitosan-alginate （C/A） gel scaffold on ADSCs.Methods The C/A gel scaffold consisted of medical-grade chitosan and alginate.Gel porosity was calculated by liquid displacement method.Pore microstructure was analyzed by light and scanning electron microscopy.ADSCs were isolated and cultured by conventional methods.Passage 2 BrdU-labeled ADSCs were co-cultured with the C/A gel.ADSCs were divided into three groups （control,normoxia-induced,and hypoxia-induced groups）.In the control group,cells were cultured in 10％ FBS/DMEM.Hypoxia-induced and normoxia-induced groups were induced by adding transforming growth factor-β1,dexamethasone,vitamin C,sodium pyruvate,proline,bone morphogenetic protein-7,and 1％ ITS-plus to the culture medium and maintaining in 2％ and 20％ O2,respectively.Histological and morphological changes were observed by light and electron microscopy.ADSCs were characterized by flow cytometry.Cell viability was investigated by BrdU incorporation.Proteoglycan and type Ⅱ collagen were measured by safranin O staining and the Sicool method,respectively.mRNA expression of hypoxia-inducing factor-1α （HIF-1α）,aggrecan,and Type Ⅱ collagen was determined by reverse transcription-polymerase chain reaction.Results C/A gels had porous exterior surfaces with 80.57％ porosity and 50-200 μm pore size.Flow cytometric analysis of passage 2 rabbit ADSCs showed high CD90 expression,while CD45 expression was very low.The morphology of induced ADSCs resembled that of NP cells.BrdU immunofluorescence showed that most ADSCs survived and proliferated in the C/A gel scaffold.Scanning electron microscopy showed that ADSCs grew well in the C/A gel scaffold.ADSCs in the C/A gel scaffold were positive for safranin O staining.Hypoxia-induced and normoxia-induced groups produced more proteoglycan and Type Ⅱ collagen than the control group （P ＜0.05）.Proteoglycan and Type Ⅱ collagen levels in the hypoxia-induced group were higher than those in the normoxia-induced group （P ＜0.05）.Compared with the control group,higher mRNA expression of HIF-1α,aggrecan,and Type Ⅱ collagen was detected in hypoxia-induced and normoxiainduced groups （P ＜0.05）.Expression of these genes in the hypoxia-induced group was significantly higher than that in the normoxia-induced group （P ＜0.05）.Conclusion ADSCs grow well in C/A gel scaffolds and differentiate toward NP-like cells that produce the same extracellular matrix as that of NP cells under certain induction conditions,which is promoted in a hypoxic state.展开更多
文摘Intervertebral disc regeneration field is rapidly growing since disc disorders represent a major health problem in industrialized countries with very few possible treatments.Indeed, current available therapies are symptomatic, and surgical procedures consist in disc removal and spinal fusion, which is not immune to regardable concerns about possible comorbidities, cost-effectiveness, secondary risks and long-lasting outcomes. This review paper aims to share recent advances in stem cell therapy for the treatment of intervertebral disc degeneration. In literature the potential use of different adult stem cells for intervertebral disc regeneration has already been reported. Bone marrow mesenchymal stromal/stem cells, adipose tissue derived stem cells, synovial stem cells, muscle-derived stem cells, olfactory neural stem cells, induced pluripotent stem cells, hematopoietic stem cells, disc stem cells, and embryonic stem cells have been studied for this purpose either in vitro or in vivo. Moreover, several engineered carriers(e.g., hydrogels), characterized by full biocompatibility and prompt biodegradation, have been designed and combined with different stem cell types in order to optimize the local and controlled delivery of cellular substrates in situ. The paper overviews the literature discussing the current status of our knowledge of the different stem cells types used as a cell-based therapy for disc regeneration.
文摘Intervertebral disc(IVD)degeneration is a leading cause of back pain and precursor to more severe conditions,including disc herniation and spinal stenosis.While traditional growth factor therapies(e.g.,TGFβ)are effective at transiently reversing degenerated disc by stimulation of matrix synthesis,it is increasingly accepted that bioscaffolds are required for sustained,complete IVD regeneration.Current scaffolds(e.g.,metal/polymer composites,non-mammalian biopolymers)can be improved in one or more IVD regeneration demands:biodegradability,noninvasive injection,recapitulated healthy IVD biomechanics,predictable crosslinking,and matrix repair induction.To meet these demands,tetrazine-norbornene bioorthogonal ligation was combined with gelatin to create an injectable bioorthogonal hydrogel(BIOGEL).The liquid hydrogel precursors remain free-flowing across a wide range of temperatures and crosslink into a robust hydrogel after 5-10 min,allowing a human operator to easily inject the therapeutic constructs into degenerated IVD.Moreover,BIOGEL encapsulation of TGFβpotentiated histological repair(e.g.,tissue architecture and matrix synthesis)and functional recovery(e.g.,high water retention by promoting the matrix synthesis and reduced pain)in an in vivo rat IVD degeneration/nucleotomy model.This BIOGEL procedure readily integrates into existing nucleotomy procedures,indicating that clinical adoption should proceed with minimal difficulty.Since bioorthogonal crosslinking is essentially non-reactive towards biomolecules,our developed material platform can be extended to other payloads and degenerative injuries.
基金This study was supported by a grant from the Natural Science Foundation of Beijing （No. 5062039）.
文摘Background Injectable three-dimensional （3D） scaffolds have the advantages of fluidity and moldability to fill irregularshaped defects,simple incorporation of bioactive factors,and limited surgical invasiveness.Adipose-derived stem cells （ADSCs） are multipotent and can be differentiated toward nucleus pulposus （NP）-Iike cells.A hypoxic environment may be important for differentiation to NP-like cells because the intervertebral disc is an avascular tissue.Hence,we investigated the induction effects of hypoxia and an injectable 3D chitosan-alginate （C/A） gel scaffold on ADSCs.Methods The C/A gel scaffold consisted of medical-grade chitosan and alginate.Gel porosity was calculated by liquid displacement method.Pore microstructure was analyzed by light and scanning electron microscopy.ADSCs were isolated and cultured by conventional methods.Passage 2 BrdU-labeled ADSCs were co-cultured with the C/A gel.ADSCs were divided into three groups （control,normoxia-induced,and hypoxia-induced groups）.In the control group,cells were cultured in 10％ FBS/DMEM.Hypoxia-induced and normoxia-induced groups were induced by adding transforming growth factor-β1,dexamethasone,vitamin C,sodium pyruvate,proline,bone morphogenetic protein-7,and 1％ ITS-plus to the culture medium and maintaining in 2％ and 20％ O2,respectively.Histological and morphological changes were observed by light and electron microscopy.ADSCs were characterized by flow cytometry.Cell viability was investigated by BrdU incorporation.Proteoglycan and type Ⅱ collagen were measured by safranin O staining and the Sicool method,respectively.mRNA expression of hypoxia-inducing factor-1α （HIF-1α）,aggrecan,and Type Ⅱ collagen was determined by reverse transcription-polymerase chain reaction.Results C/A gels had porous exterior surfaces with 80.57％ porosity and 50-200 μm pore size.Flow cytometric analysis of passage 2 rabbit ADSCs showed high CD90 expression,while CD45 expression was very low.The morphology of induced ADSCs resembled that of NP cells.BrdU immunofluorescence showed that most ADSCs survived and proliferated in the C/A gel scaffold.Scanning electron microscopy showed that ADSCs grew well in the C/A gel scaffold.ADSCs in the C/A gel scaffold were positive for safranin O staining.Hypoxia-induced and normoxia-induced groups produced more proteoglycan and Type Ⅱ collagen than the control group （P ＜0.05）.Proteoglycan and Type Ⅱ collagen levels in the hypoxia-induced group were higher than those in the normoxia-induced group （P ＜0.05）.Compared with the control group,higher mRNA expression of HIF-1α,aggrecan,and Type Ⅱ collagen was detected in hypoxia-induced and normoxiainduced groups （P ＜0.05）.Expression of these genes in the hypoxia-induced group was significantly higher than that in the normoxia-induced group （P ＜0.05）.Conclusion ADSCs grow well in C/A gel scaffolds and differentiate toward NP-like cells that produce the same extracellular matrix as that of NP cells under certain induction conditions,which is promoted in a hypoxic state.
