The regeneration of osteochondral defects remains a significant challenge due to the distinct structural and functional requirements of cartilage and subchondral bone.Current strategies often employ multiphasic scaffo...The regeneration of osteochondral defects remains a significant challenge due to the distinct structural and functional requirements of cartilage and subchondral bone.Current strategies often employ multiphasic scaffolds to mimic the complex osteochondral unit.In this study,we developed an injectable hydrogel system with inner and outer layers exhibiting distinct degradation rates and cell combinations,designed to regenerate critical-sized osteochondral defects in a long-term rabbit model.The hydrogel system is based on elastin-like recombinamers(ELRs),which promote cell adhesion,proliferation,and mechanical integrity.Bioactive sequences,including RGD for cell adhesion and proteolytic motifs with different degradation kinetics,slow-cleaving(DRIR)and fast-cleaving(GTAR),were incorporated into the design.These hydrogels are delivered in liquid form,solidifying in situ to conform to osteochondral defects.To explore the role of cellular interactions,mesenchymal stem cells(MSCs)and chondrocytes were incorporated into the hydrogels.After six months in vivo,outcomes were evaluated via glycosaminoglycan quantification,histological,and immunohistochemistry analyses,revealing cartilage-like tissue production.Statistical analysis using a modified O’Driscoll score demonstrated significant differences(p<0.05)between homogeneous hydrogels(with either fast or slow degradation rates)and both the untreated control and the chondrocyte-only condition.No significant differences were found among other experimental groups based on the O’Driscoll score;however,histological analysis confirmed promising cartilage-like tissue formation,even in the cell-free hydrogel condition.These findings highlight the potential of in situ crosslinkable ELR hydrogels as a versatile and effective strategy for osteochondral repair,demonstrating substantial cartilage-like tissue formation,even without cellular components.Moreover,the incorporation of MSCs—likely through paracrine signaling—significantly enhanced overall regenerative outcomes,offering a promising stem cell–based approach for treating osteochondral lesions.展开更多
基金funding from the Spanish Government(grants PID2021‐122444OB‐100 and PID2022‐137484OB‐I00 funded by MCIN/AEI/10.13039/501100011033 and by ERDF,EU)the Department of Education,Junta de Castilla y León(grant VA188P23 and CLU-2023-1-05 cofunded by ERDF)Centro en Red de Medicina Regenerativa y Terapia Celular de Castilla y León.
文摘The regeneration of osteochondral defects remains a significant challenge due to the distinct structural and functional requirements of cartilage and subchondral bone.Current strategies often employ multiphasic scaffolds to mimic the complex osteochondral unit.In this study,we developed an injectable hydrogel system with inner and outer layers exhibiting distinct degradation rates and cell combinations,designed to regenerate critical-sized osteochondral defects in a long-term rabbit model.The hydrogel system is based on elastin-like recombinamers(ELRs),which promote cell adhesion,proliferation,and mechanical integrity.Bioactive sequences,including RGD for cell adhesion and proteolytic motifs with different degradation kinetics,slow-cleaving(DRIR)and fast-cleaving(GTAR),were incorporated into the design.These hydrogels are delivered in liquid form,solidifying in situ to conform to osteochondral defects.To explore the role of cellular interactions,mesenchymal stem cells(MSCs)and chondrocytes were incorporated into the hydrogels.After six months in vivo,outcomes were evaluated via glycosaminoglycan quantification,histological,and immunohistochemistry analyses,revealing cartilage-like tissue production.Statistical analysis using a modified O’Driscoll score demonstrated significant differences(p<0.05)between homogeneous hydrogels(with either fast or slow degradation rates)and both the untreated control and the chondrocyte-only condition.No significant differences were found among other experimental groups based on the O’Driscoll score;however,histological analysis confirmed promising cartilage-like tissue formation,even in the cell-free hydrogel condition.These findings highlight the potential of in situ crosslinkable ELR hydrogels as a versatile and effective strategy for osteochondral repair,demonstrating substantial cartilage-like tissue formation,even without cellular components.Moreover,the incorporation of MSCs—likely through paracrine signaling—significantly enhanced overall regenerative outcomes,offering a promising stem cell–based approach for treating osteochondral lesions.
