Implants made of magnesium(Mg)are increasingly employed in patients to achieve osteosynthesis while degrading in situ.Since Mg implants and Mg^(2+)have been suggested to possess anti-inflammatory properties,the clinic...Implants made of magnesium(Mg)are increasingly employed in patients to achieve osteosynthesis while degrading in situ.Since Mg implants and Mg^(2+)have been suggested to possess anti-inflammatory properties,the clinically observed soft tissue inflammation around Mg implants is enigmatic.Here,using a rat soft tissue model and a 1-28 d observation period,we determined the temporo-spatial cell distribution and behavior in relation to sequential changes of pure Mg implant surface properties and Mg^(2+)release.Compared to nondegradable titanium(Ti)implants,Mg degradation exacerbated initial inflammation.Release of Mg degradation products at the tissue-implant interface,culminating at 3 d,actively initiated chemotaxis and upregulated mRNA and protein immunomodulatory markers,particularly inducible nitric oxide synthase and toll-like receptor-4 up to 6 d,yet without a cytotoxic effect.Increased vascularization was demonstrated morphologically,preceded by high expression of vascular endothelial growth factor.The transition to appropriate tissue repair coincided with implant surface enrichment of Ca and P and reduced peri-implant Mg^(2+)concentration.Mg implants revealed a thinner fibrous encapsulation compared with Ti.The detailed understanding of the relationship between Mg material properties and the spatial and time-resolved cellular processes provides a basis for the interpretation of clinical observations and future tailoring of Mg implants.展开更多
Calcium phosphates(CaP)represent an important class of osteoconductive and osteoinductive biomaterials.As proof-of-concept,we show how a multi-component CaP formulation(monetite,beta-tricalcium phosphate,and calcium p...Calcium phosphates(CaP)represent an important class of osteoconductive and osteoinductive biomaterials.As proof-of-concept,we show how a multi-component CaP formulation(monetite,beta-tricalcium phosphate,and calcium pyrophosphate)guides osteogenesis beyond the physiological envelope.In a sheep model,hollow dome-shaped constructs were placed directly over the occipital bone.At 12 months,large amounts of bone(~75%)occupy the hollow space with strong evidence of ongoing remodelling.Features of both compact bone(osteonal/osteon-like arrangements)and spongy bone(trabeculae separated by marrow cavities)reveal insights into function/need-driven microstructural adaptation.Pores within the CaP also contain both woven bone and vascularised lamellar bone.Osteoclasts actively contribute to CaP degradation/removal.Of the constituent phases,only calcium pyrophosphate persists within osseous(cutting cones)and non-osseous(macrophages)sites.From a translational perspective,this multi-component CaP opens up exciting new avenues for osteotomy-free and minimally-invasive repair of large bone defects and augmentation of the dental alveolar ridge.展开更多
文摘Implants made of magnesium(Mg)are increasingly employed in patients to achieve osteosynthesis while degrading in situ.Since Mg implants and Mg^(2+)have been suggested to possess anti-inflammatory properties,the clinically observed soft tissue inflammation around Mg implants is enigmatic.Here,using a rat soft tissue model and a 1-28 d observation period,we determined the temporo-spatial cell distribution and behavior in relation to sequential changes of pure Mg implant surface properties and Mg^(2+)release.Compared to nondegradable titanium(Ti)implants,Mg degradation exacerbated initial inflammation.Release of Mg degradation products at the tissue-implant interface,culminating at 3 d,actively initiated chemotaxis and upregulated mRNA and protein immunomodulatory markers,particularly inducible nitric oxide synthase and toll-like receptor-4 up to 6 d,yet without a cytotoxic effect.Increased vascularization was demonstrated morphologically,preceded by high expression of vascular endothelial growth factor.The transition to appropriate tissue repair coincided with implant surface enrichment of Ca and P and reduced peri-implant Mg^(2+)concentration.Mg implants revealed a thinner fibrous encapsulation compared with Ti.The detailed understanding of the relationship between Mg material properties and the spatial and time-resolved cellular processes provides a basis for the interpretation of clinical observations and future tailoring of Mg implants.
文摘Calcium phosphates(CaP)represent an important class of osteoconductive and osteoinductive biomaterials.As proof-of-concept,we show how a multi-component CaP formulation(monetite,beta-tricalcium phosphate,and calcium pyrophosphate)guides osteogenesis beyond the physiological envelope.In a sheep model,hollow dome-shaped constructs were placed directly over the occipital bone.At 12 months,large amounts of bone(~75%)occupy the hollow space with strong evidence of ongoing remodelling.Features of both compact bone(osteonal/osteon-like arrangements)and spongy bone(trabeculae separated by marrow cavities)reveal insights into function/need-driven microstructural adaptation.Pores within the CaP also contain both woven bone and vascularised lamellar bone.Osteoclasts actively contribute to CaP degradation/removal.Of the constituent phases,only calcium pyrophosphate persists within osseous(cutting cones)and non-osseous(macrophages)sites.From a translational perspective,this multi-component CaP opens up exciting new avenues for osteotomy-free and minimally-invasive repair of large bone defects and augmentation of the dental alveolar ridge.
