Human gingival fibroblasts function is stimulated on machined hydrided titanium zirconium dental implants

Objectives

The aim of this study was to evaluate the influence of different titanium zirconium (TiZr) alloy surfaces on primary human gingival fibroblasts (HGF) for improved soft tissue integration of dental implants.

Methods

TiZr polished, machined and machined + HCl/H₂SO₄ acid-etched surfaces were modified by cathodic polarization and/or HNO₃/HF acid etching. Contact angle of surfaces was measured. The influence of modified TiZr surfaces on HGF was evaluated through the analysis of cell number, morphology, recovery after a wound (wound healing assay) and the expression of several genes, including matrix metalloproteinase-1 (MMP1) and metallopeptidase inhibitor-1 (TIMP1).

Results

Modification of TiZr surfaces decreased its hydrophilicity. Hydride implementation on TiZr surfaces via cathodic polarization increased TIMP1 expression and decreased MMP1/TIMP1 mRNA ratio. Cathodic polarization of machined surfaces promoted cell attachment. Cells on machined and machined + cathodic polarization surfaces grew aligned to the microgrooves whereas on all polished surfaces they grew randomly. Acid etching of polished and machined surfaces did not improve HGF function.

Conclusions

Hydride implementation on TiZr machined surfaces may be used as new dental implant material for improved soft tissue integration.

Clinical significance

Enhancing dental implant surfaces’ bioactivity by hydride implementation may promote soft tissue attachment and sealing around the implant and reduce peri-implantitis related to ECM-destruction compared with conventional machined surfaces.     

Nuclear magnetic resonance imaging of airways in humans with use of hyperpolarized 3He

The nuclear spin polarization of noble gases can be enhanced strongly by laser optical pumping followed by electron-nuclear polarization transfer. Direct optical pumping of metastable ³He atoms has been shown to produce enormous polarization on the order of 0.4–0.6. This is about 10⁵ times larger than the polarization of water protons at thermal equilibrium used in conventional MRI. We demonstrate that hyper-polarized ³He gas can be applied to nuclear magnetic resonance imaging of organs with air-filled spaces in humans. In vivo ³He MR experiments were performed in a whole-body MR scanner with a superconducting magnet ramped down to 0.8 T. Anatomical details of the upper respiratory tract and of the lungs of a volunteer were visualized with the FLASH technique demonstrating the potential of the method for fast imaging of airways in the human body and for pulmonary ventilation studies.     

Ion Microprobe Study of the Polarization Quenching Techniques in Single Crystal Diamond Radiation Detectors

Synthetic single crystal diamond grown using the chemical vapor deposition technique constitutes an extraordinary candidate material for monitoring radiation in extreme environments. However, under certain conditions, a progressive creation of space charge regions within the crystal can lead to the deterioration of charge collection efficiency. This phenomenon is called polarization and represents one of the major drawbacks associated with using this type of device. In this study, we explore different techniques to mitigate the degradation of signal due to polarization. For this purpose, two different diamond detectors are characterized by the ion beam-induced charge technique using a nuclear microprobe, which utilizes MeV energy ions of different penetration depths to probe charge transport in the detectors. The effect of polarization is analyzed by turning off the bias applied to the detector during continuous or discontinuous irradiation, and also by alternating bias polarity. In addition, the beneficial influence of temperature for reducing the effect of polarization is also observed. Finally, the effect of illuminating the detector with light is also measured. Our experimental results indicate that heating a detector or turning off the bias, and then applying it during continuous irradiation can be used as satisfactory methods for recovering the CCE value close to that of a prepolarized state. In damaged regions, illumination with white light can be used as a standard method to suppress the strength of polarization induced by holes.     

Kellerin alleviates cognitive impairment in mice after ischemic stroke by multiple mechanisms

Ischemic stroke is a global disease with high disability and mortality rates. Cognitive impairment is one of the major clinical features of ischemic stroke, and microglia‐mediated inflammation has been shown to be an important contributor to the pathogenesis of ischemic stroke. Kellerin, extracted from Ferula sinkiangensis, was previously shown to inhibit microglial activation and exert a strong anti‐neuroinflammatory effect. However, there is no report of the potential therapeutic effect of kellerin on ischemic stroke by targeting microglial cells. In this study, we wanted to examine the effects of kellerin on ischemic stroke in the bilateral common carotid artery occlusion (BCCAO) model and the lipopolysaccharide (LPS)‐activated microglia model. We found that kellerin alleviated cognitive impairment, decreased neuronal loss, suppressed microglial activation, and transformed microglia from the pro‐inflammatory M1 phenotype to the anti‐inflammatory M2 phenotype in BCCAO mice. Moreover, in in vitro studies, we found that kellerin regulated microglial polarization and inhibited the NLRP3 and MAPK signaling pathways after LPS treatment. These findings provide a new understanding of the function of kellerin in ischemic stroke, and suggest that kellerin could be a potential therapeutic agent for the treatment of ischemic stroke.     

活性多酚化合物LM49对RAW264.7巨噬细胞极化的影响

目的初步探讨LM49(2,4'三羟基-5,2'-二溴二苯甲酮)对脂多糖(LPS)联合干扰素γ(IFN-γ)诱导的小鼠单核巨噬细胞(RAW264.7)M1/M2极化的影响及其调控机制。方法四曱基偶氮唑蓝(MTT)法测定LM49对细胞活力的影响;流式细胞术、实时荧光定量聚合酶链反应(PCR)和Westem-blot法测定LM49(5,10,20μmol·L^-1)与LPS/INF-γ共同作用于RAW264.7细胞后,巨噬细胞亚型标志物的表达情况及对核因子(NF)-κB和JAK/STAT信号通路的影响。结果与LPS/INF-γ造模组相比,LM49显著抑制CD16/32^+细胞数及诱导型一氧化氮合酶(iNOS)、白细胞介素(IL)4和肿瘤坏死因子(TNF)-αmRNA的表达,升高CD206^+细胞数及Arg-1和IL-10 mRNA的表达,且降低巨噬细胞M1/M2的比值;Westem-blot法验证LM49可显著降低TLR4、Myd88、NF-κB和STAT1蛋白的表达量,同时抑制p-JAK2和p-STATl蛋白磷酸化水平。结论LM49通过抑制TLR4-Myd88-NF-κB和JAK2-STAT1信号通路,抑制巨噬细胞Ml型极化及促进巨噬细胞M2型极化,调节巨噬细胞M1/M2的平衡。     

巨噬细胞的骨免疫学效应

背景：巨噬细胞以其显著的骨免疫学效应得到学者们的广泛关注,其功能和应用已成为研究热点。目前研究主要涉及巨噬细胞的起源、极化、骨免疫学效应及其在骨修复中的应用。目的：综述巨噬细胞的骨免疫学效应及其在骨修复中应用的研究进展,证实巨噬细胞在骨组织工程中具有卓越的研究价值和应用前景。方法：利用PubMed、Web of Science和CNKI数据库检索2010-2022年发表的相关文献,检索词为“巨噬细胞极化、骨、成骨、骨免疫学、生物材料、组织工程”“macrophage polarization,bone,osteogenesis,osteoimmunology,biomaterials,tissue engineering”,并纳入少量年份久远的经典文献。通过阅读标题和摘要进行初筛,排除与文章主题不相关的文献,最终纳入120篇文献进行综述分析。结果与结论：(1)巨噬细胞包括单核细胞来源的炎性巨噬细胞和组织驻留巨噬细胞,其中不同组织的驻留巨噬细胞具有不同的发育起源组合,绝大多数组织驻留巨噬细胞起源于胚胎时期的卵黄囊;(2)巨噬细胞具有高度可塑性,在不同刺激下极化为M1/M2表型,分别释放促...     

Profilin 1 knockdown prevents ischemic brain damage by promoting M2 microglial polarization associated with the RhoA/ROCK pathway

Microglial polarization to the anti-inflammatory M2 phenotype is essential in resolving neuroinflammation, making it a promising therapeutic strategy for stroke intervention. The actin cytoskeleton is known to be important for the physiological functions of microglia, including migration and phagocytosis. Profilin 1 (PFN1), an actin-binding protein, is involved in the dynamic transformation and reorganization of actin. However, the role of PFN1 in microglial polarization and ischemia/reperfusion injury is unclear. The role of PFN1 on microglial polarization was examined in vitro in BV2 microglial cells subjected to oxygen-glucose deprivation/reoxygenation (OGDR) and in vivo in male mice after transient middle cerebral artery occlusion (MCAO). Knockdown of PFN1 inhibited M1 microglial polarization and promoted M2 microglia polarization 48 hr after OGDR stimulation in BV2 cells and 7 days after MCAO-induced injury in male mice. RhoA/ROCK pathway was involved in the regulation of PFN1 during microglial polarization. Knockdown of PFN1 also significantly attenuated brain infarcts and edema, improved cerebral blood flow and neurological deficits in MCAO-injured mice. Inhibition of PFN1 effectively protected the brain against ischemia/reperfusion injuries by promoting M2 microglial polarization in vitro and in vivo.     

Generation of A Space-Variant Vector Beam with Catenary-Shaped Polarization States

We demonstrate the generation of a space-variant vector beam with catenary-shaped polarization states based on the polarization interferometry. With a spatial light modulator and a common path interferometric configuration, two orthogonally circularly polarized beams with different phase modulation overlap each other, yielding the vector beams. In addition, the polarization states of this vector beam are scalable to the arbitrary spatial distribution because of its great flexibility and universal applicability. It is expected that this vector beam may have many potential and intriguing applications in the micro/nano material processing, liquid crystal elements fabrication and optical micro-manipulation, and so on.     

巨噬细胞极化与动脉粥样硬化

巨噬细胞是动脉粥样硬化过程中最具代表性的炎症细胞。机体通过多个信号通路选择性表达靶基因,使巨噬细胞呈现相应特征性的分子标志物,最终实现不同极性及功能,即促炎的M1型和抗炎的M2型巨噬细胞。MI/M2型巨噬细胞具有可塑性,二者的分化影响着动脉粥样硬化的发展结局。因此,如何控制巨噬细胞介导的炎症反应已成为心血管领域的关注热点,也为动脉粥样硬化的防治带来新的希望。     

Macrophage polarization in response to wear particles in vitro

Total joint replacement is a highly successful surgical procedure for treatment of patients with disabling arthritis and joint dysfunction. However, over time, with high levels of activity and usage of the joint, implant wear particles are generated from the articulating surfaces. These wear particles can lead to activation of an inflammatory reaction, and subsequent bone resorption around the implant （periprosthetic osteolysis）. Cells of the monocyte/macrophage lineage orchestrate this chronic inflammatory response, which is dominated by a pro-inflammatory （M 1） macrophage phenotype rather than an anti-inflammatory pro-tissue healing （M2） macrophage phenotype. While it has been shown that interleukin-4 （IL-4） selectively polarizes macrophages towards an M2 anti-inflammatory phenotype which promotes bone healing, rather than inflammation, little is known about the time course in which this occurs or conditions in which repolarization through I L-4 is most effective. The goal of this work was to study the time course of murine macrophage polarization and cytokine release in response to challenge with combinations of polymethyl methacrylate （PMMA） particles, lipopolysaccharide （LPS） and IL-4 in vitro. Treatment of particle-challenged monocyte/macrophages with IL-4 led to an initial suppression of pro-inflammatory cytokines and inducible nitric oxide synthase （iNOS） production and subsequent polarization into an M2 anti-inflammatory phenotype. This result was optimized when IL-4 was delivered before PMMA particle challenge, to an M 1 phenotype rather than to uncommitted （MO） macrophages. The effects of this polarization were sustained over a 5-day time course. Polarization of M1 macrophages into an M2 phenotype may be a strategy to mitigate wear particle associated periprosthetic osteolysis.