Ma Jun
,
Zhao Nan
,
Betts Lexxus
,
Zhu Donghui
材料科学技术（英）
doi:10.1016/j.jmst.2015.12.018
Biodegradable magnesium (Mg) alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept “bio-adaption” between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases: inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products (e.g., ions and hydrogen) will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed.
关键词:
Mg stent
,
Bio-adaptation
,
Vessel
,
Wound healing
Chen Shaoming
,
Gao Manman
,
Zhou Zhiyu
,
Liang Jiabi
,
Gong Ming
,
Dai Xuejun
,
Liang Tangzhao
,
Ye Jiacheng
,
Wu Gang
,
Zou Lijin
,
Wang Yingjun
,
Zou Xuenong
材料科学技术（英）
doi:10.1016/j.jmst.2016.08.001
Although cartilage tissue engineering has been developed for decades, it is still unclear whether angiogenesis was the accompaniment of chondrogenesis in cartilage regeneration. This study aimed to explore the process of anti-angiogenesis during cartilage regenerative progress in cartilage repair extracellular matrix (ECM) materials under Hypoxia. C3H10T1/2 cell line, seeded as pellet or in ECM materials, was added with chondrogenic medium or DMEM medium for 21 days under hypoxia or normoxia environment. Genes and miRNAs related with chondrogenesis and angiogenesis were detected by RT-qPCR technique on Days 7, 14, and 21. Dual-luciferase report system was used to explore the regulating roles of miRNAs on angiogenesis. Results showed that the chondrogenic medium promotes chondrogenesis both in pellet and ECM materials culture. HIF1α was up-regulated under hypoxia compared with normoxia (P?<?0.05). Meanwhile, hypoxia enhanced chondrogenesis. miR-140-5p exhibited higher expression while miR-146b exhibited lower expression. The chondrogenic phenotype was more stabilized in the ECM materials in chondrogenic medium than DMEM medium, with lower VEGFα expression even under hypoxia. Dual-luciferase report assays demonstrated that miR-140-5p directly targets VEGFα by binding its 3′-UTR. Taken together, chondrogenic cytokines, ECM materials and hypoxia synergistically promoted chondrogenesis and inhibited angiogenesis. miR-140-5p played an important role in this process.
关键词:
Biomaterials
,
Bio-adaptation
,
Hypoxia
,
Chondrogenesis
,
Angiogenesis
,
miRNAs
