The introduction of neurotrophic factors into injured peripheral nerve sites is beneficial to peripheral nerve regeneration.However,neurotrophic facto rs are rapidly degraded in vivo and obstruct axonal regeneration w...The introduction of neurotrophic factors into injured peripheral nerve sites is beneficial to peripheral nerve regeneration.However,neurotrophic facto rs are rapidly degraded in vivo and obstruct axonal regeneration when used at a supraphysiological dose,which limits their clinical benefits.Bioactive mimetic peptides have been developed to be used in place of neurotrophic factors because they have a similar mode of action to the original growth fa ctors and can activate the equivalent receptors but have simplified sequences and structures.In this study,we created polydopamine-modified chitin conduits loaded with brain-derived neurotrophic factor mimetic peptides and vascular endothelial growth fa ctor mimetic peptides(Chi/PDA-Ps).We found that the Chi/PDA-Ps conduits were less cytotoxic in vitro than chitin conduits alone and provided sustained release of functional peptides.In this study,we evaluated the biocompatibility of the Chi/P DA-Ps conduits.Brain-derived neurotrophic factor mimetic peptide and vascular endothelial growth fa ctor mimetic peptide synergistically promoted prolife ration of Schwann cells and secretion of neurotrophic factors by Schwann cells and attachment and migration of endothelial cells in vitro.The Chi/P DA-Ps conduits were used to bridge a 2 mm gap between the nerve stumps in rat models of sciatic nerve injury.We found that the application of Chi/PDA-Ps conduits could improve the motor function of rats and reduce gastrocnemius atrophy.The electrophysiological results and the microstructure of regenerative nerves showed that the nerve conduction function and re myelination was further resto red.These findings suggest that the Chi/PDA-Ps conduits have great potential in peripheral nerve injury repair.展开更多
Hyaline cartilage plays a critical role in maintaining joint function and pain.However,the lack of blood supply,nerves,and lymphatic vessels greatly limited the self-repair and regeneration of damaged cartilage,giving...Hyaline cartilage plays a critical role in maintaining joint function and pain.However,the lack of blood supply,nerves,and lymphatic vessels greatly limited the self-repair and regeneration of damaged cartilage,giving rise to various tricky issues in medicine.In the past 30 years,numerous treatment techniques and commercial products have been developed and practiced in the clinic for promoting defected cartilage repair and regeneration.Here,the current therapies and their relevant advantages and disadvantages will be summarized,particularly the tissue engineering strategies.Furthermore,the fabrication of tissue-engineered cartilage under research or in the clinic was discussed based on the traid of tissue engineering,that is the materials,seed cells,and bioactive factors.Finally,the commercialized cartilage repair products were listed and the regulatory issues and challenges of tissue-engineered cartilage repair products and clinical application would be reviewed.展开更多
基金the National Natural Science Foundation of China,Nos.31771322,31571235the Natural Science Foundation of Beijing,No.7212121+3 种基金Beijing Science Technology New Star Cross Subject of China,No.2018019Shenzhen Science and Technology Plan Project of China,No.JCYJ 20190806162205278the Key Laboratory of Trauma and Neural Regeneration(Peking University),Ministry of Educationa grant from National Center for Trauma Medicine,No.BMU2020XY005-01(all to PXZ)。
文摘The introduction of neurotrophic factors into injured peripheral nerve sites is beneficial to peripheral nerve regeneration.However,neurotrophic facto rs are rapidly degraded in vivo and obstruct axonal regeneration when used at a supraphysiological dose,which limits their clinical benefits.Bioactive mimetic peptides have been developed to be used in place of neurotrophic factors because they have a similar mode of action to the original growth fa ctors and can activate the equivalent receptors but have simplified sequences and structures.In this study,we created polydopamine-modified chitin conduits loaded with brain-derived neurotrophic factor mimetic peptides and vascular endothelial growth fa ctor mimetic peptides(Chi/PDA-Ps).We found that the Chi/PDA-Ps conduits were less cytotoxic in vitro than chitin conduits alone and provided sustained release of functional peptides.In this study,we evaluated the biocompatibility of the Chi/P DA-Ps conduits.Brain-derived neurotrophic factor mimetic peptide and vascular endothelial growth fa ctor mimetic peptide synergistically promoted prolife ration of Schwann cells and secretion of neurotrophic factors by Schwann cells and attachment and migration of endothelial cells in vitro.The Chi/P DA-Ps conduits were used to bridge a 2 mm gap between the nerve stumps in rat models of sciatic nerve injury.We found that the application of Chi/PDA-Ps conduits could improve the motor function of rats and reduce gastrocnemius atrophy.The electrophysiological results and the microstructure of regenerative nerves showed that the nerve conduction function and re myelination was further resto red.These findings suggest that the Chi/PDA-Ps conduits have great potential in peripheral nerve injury repair.
文摘Hyaline cartilage plays a critical role in maintaining joint function and pain.However,the lack of blood supply,nerves,and lymphatic vessels greatly limited the self-repair and regeneration of damaged cartilage,giving rise to various tricky issues in medicine.In the past 30 years,numerous treatment techniques and commercial products have been developed and practiced in the clinic for promoting defected cartilage repair and regeneration.Here,the current therapies and their relevant advantages and disadvantages will be summarized,particularly the tissue engineering strategies.Furthermore,the fabrication of tissue-engineered cartilage under research or in the clinic was discussed based on the traid of tissue engineering,that is the materials,seed cells,and bioactive factors.Finally,the commercialized cartilage repair products were listed and the regulatory issues and challenges of tissue-engineered cartilage repair products and clinical application would be reviewed.
