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19 result(s) for "Chen, Xiteng"
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Exosomes derived from MSCs ameliorate retinal laser injury partially by inhibition of MCP-1
Although accumulated evidence supports the notion that mesenchymal stem cells (MSCs) act in a paracrine manner, the mechanisms are still not fully understood. Recently, MSC-derived exosomes (MSC-Exos), a type of microvesicle released from MSCs, were thought to carry functional proteins and RNAs to recipient cells and play therapeutic roles. In the present study, we intravitreally injected MSCs derived from either mouse adipose tissue or human umbilical cord and their exosomes to observe and compare their functions in a mouse model of laser-induced retinal injury. We found that both MSCs and their exosomes reduced damage, inhibited apoptosis and suppressed inflammatory responses to obtain better visual function to nearly the same extent in vivo . Obvious down-regulation of monocyte chemotactic protein (MCP)-1 in the retina was found after MSC-Exos injection. In vitro , MSC-Exos also down-regulated MCP-1 mRNA expression in primarily cultured retinal cells after thermal injury. It was further demonstrated that intravitreal injection of an MCP-1-neutralizing antibody promoted the recovery of retinal laser injury, whereas the therapeutic effect of exosomes was abolished when MSC-Exos and MCP-1 were administrated simultaneously. Collectively, these results suggest that MSC-Exos ameliorate laser-induced retinal injury partially through down-regulation of MCP-1.
Effects of Mesenchymal Stem Cell-Derived Exosomes on Experimental Autoimmune Uveitis
We previously demonstrated that mesenchymal stem cells (MSCs) ameliorated experimental autoimmune uveoretinitis (EAU) in rats. Recently, MSC-derived exosomes (MSC-Exo) were thought to carry functions of MSCs. In this study, we tested the effect of local administration of human MSC-Exo on established EAU in the same species. Rats with EAU induced by immunization with interphotoreceptor retinol-binding protein 1177–1191 peptide were treated by periocular injections of increasing doses of MSC-Exo starting at the disease onset for 7 consecutive days. The in vitro effects of MSC-Exo on immune cell migration and responder T cell proliferation were examined by chemotactic assays and lymphocyte proliferation assays, respectively. We found that MSC-Exo greatly reduced the intensity of ongoing EAU as their parent cells by reducing the infiltration of T cell subsets, and other inflammatory cells, in the eyes. Furthermore, the chemoattractive effects of CCL2 and CCL21 on inflammatory cells were inhibited by MSC-Exo. However, no inhibitory effect of MSC-Exo on IRBP-specific T cell proliferation was observed. These results suggest that MSC-Exo effectively ameliorate EAU by inhibiting the migration of inflammatory cells, indicating a potential novel therapy of MSC-Exo for uveitis.
Effectiveness of toric intraocular lens implantation for correcting irregular corneal astigmatism in cataract eyes
A retrospective cohort study was conducted to observe the correction effect of Toric intraocular lens (IOL) implantation in cataract eyes with specific types of irregular corneal astigmatism. Thirty-four eyes with either the \"asymmetric bow-tie\" pattern (Type I) or the \"angled bow-tie\" pattern (Type II) were included. Corneal topography was assessed using Pentacam HR, and changes in preoperative corneal astigmatism, visual acuity, manifest refraction, and objective visual quality were measured and compared. The average uncorrected distance visual acuity improved significantly from 0.86 ± 0.40 logMAR to 0.22 ± 0.15 logMAR (P < 0.001). Preoperative corneal astigmatism of 2.05 ± 0.90 D was corrected to a postoperative residual astigmatism of 0.78 ± 0.57 D (P < 0.001), with 32% of eyes within 0.50 D. The residual astigmatism prediction errors in Type I and Type II cases were (0.97 ± 0.68 D) and (0.66 ± 0.37 D), respectively (P = 0.100). The mean spherical equivalent prediction error in Type II cases (0.07 ± 0.36 D) was significantly smaller than that in Type I cases (− 0.29 ± 0.52 D) (P = 0.030). This study concludes that Toric IOL implantation effectively corrects specific types of irregular corneal astigmatism in cataract surgery. Eyes with the \"angled bow-tie\" pattern show higher accuracy in refractive predictions compared to eyes with the \"asymmetric bow-tie\" pattern.
A Multi-Mode Wireless Power Transfer System Based on a Reconfigurable Transmitter for Charging Electric Bicycles
Due to the diverse needs of users, such as the requirement for rapid charging in time-sensitive situations and the need to minimize battery power consumption to extend battery life when the device is idle, a wireless charging system that combines fast and slow charging capabilities is crucial for adapting to various usage scenarios. This paper proposes a multi-mode wireless charging system based on a reconfigurable transmitter, which can simultaneously charge different types of batteries with both fast and slow charging capabilities. By applying different control logic to the power devices in the reconfigurable inverter, the system can achieve four operating modes: two different constant current (CC) modes and two different constant voltage (CV) modes. Furthermore, the system can switch between these modes by configuring the MOSFETs operating states: two three-coil configurations are used for the two CC modes, while two two-coil configurations are used for the two CV modes. Therefore, the system exhibits high versatility. To verify the theoretical analysis of the proposed system, an experimental prototype with an output specification of 3 A/2.2 A/78 V/65 V is built.
The influence of corneal biomechanical factors on surgically induced corneal astigmatism
To investigate the correlation between the corneal biomechanical properties of cataract patients measured by Corvis-ST and surgically induced corneal astigmatism (CSIA) derived from anterior segment swept-source OCT (CASIA2). A total of 149 eyes from 149 patients received phacoemulsification with a 2.2-mm clear corneal incision at the 135° were involved. Before surgery, all patients were examined by Corvis-ST for dynamic corneal response parameters (DCRs). The total corneal astigmatism was measured using CASIA2 before the operation and at 1 month follow-up. CSIA was obtained using Alpins vector analysis. After adjustment for age, central corneal thickness, and biomechanically corrected intraocular pressure, partial correlation analysis was used to analyze the correlation between the CSIA and DCRs. The centroid of CSIA was 0.48 D @ 43°, with a magnitude of 0.75 ± 0.44 D. The age of the patient was positively correlated with the magnitude of CSIA ( r  = .22, P  = .009). The partial correlation analysis revealed that deformation amplitude ratio (DA ratio, r = -.17, P  = .045) and integrated radius (IR, r = − .20, P  = .014) were both negatively correlated with the magnitude of CSIA. The magnitude of CSIA can be expressed as: . DA ratio and IR were negatively correlated with the magnitude of CSIA in 2.2-mm cataract surgery indicating an association of increased corneal stiffness with increased magnitude of CSIA.
Characteristics of antibiotic resistance genes in full-scale anaerobic digesters of food waste and the effects of application of biogas slurry on soil antibiotic resistance genes
The fate of antibiotic resistance genes (ARGs) in full-scale anaerobic digestion (AD) of food waste (FW) and in the soil applied with biogas slurry has not been fully understood. In this study, 12 targeted ARGs and intI1 in FW, intermediate product, and biogas slurry from three full-scale AD were analyzed. The results showed that subcritical water pretreatment was an effective method for ARG attenuation, by which the absolute abundance of total targeted ARGs was removed by 99.69%. The predominant ARGs ( ermB , tetM , and tetW ) in FW were removed more than 99% after subcritical water pretreatment. The result of field experiments with biogas slurry as fertilizer showed that the absolute abundance of several ARGs ( sul2 , tetM , blaOXA-1 , blaTEM ) and intI1 accumulated significantly compared to the control group (CK) during three consecutive growth stages of the rice. The detected abundance of ARGs in paddy field soil increased from 190.50 (CK) to 8.87 × 10 4 copies/g (wet weight) (soil) during tillering stage, and increased from 4102.65 (CK) to 4.38 × 10 4 copies/g (wet weight) (soil) during heading time. Biogas slurry improved the soil nutrients (TN, AN, TP, and AP); meanwhile, the concentrations of total salt and Cl − increased. Network analysis indicated that 28 genera were the possible hosts of ARGs; variation partitioning analysis (VPA) indicated that microbial communities (contribution 59.30%) were the main factors that affected the fate of ARGs and intI1 .
Enhanced immunosuppressive capability of mesenchymal stem cell-derived small extracellular vesicles with high expression of CD73 in experimental autoimmune uveitis
Background Autoimmune uveitis is an inflammatory disease triggered by an aberrant immune response. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) are emerging as potential therapeutic agents for this condition. CD73, an ectoenzyme present on MSC-sEVs, is involved in mitigating inflammation by converting extracellular adenosine monophosphate into adenosine. We hypothesize that the inhibitory effect of MSC-sEVs on experimental autoimmune uveitis (EAU) could be partially attributed to the surface expression of CD73. Methods To investigate novel therapeutic approaches for autoimmune uveitis, we performed lentiviral transduction to overexpress CD73 on the surface of MSC-sEVs, yielding CD73-enriched MSC-sEVs (sEVs-CD73). Mice with interphotoreceptor retinoid-binding protein (IRBP)-induced EAU were grouped randomly and treated with 50 µg MSC-sEVs, vector infected MSC-sEVs, sEVs-CD73 or PBS via single tail vein injection. We evaluated the clinical and histological features of the induced mice and analyzed the proportion and functional capabilities of T helper cells. Furthermore, T-cells were co-cultured with various MSC-sEVs in vitro, and we quantified the resulting inflammatory response to assess the potential therapeutic benefits of sEVs-CD73. Results Compared to MSC-sEVs, sEVs-CD73 significantly alleviates EAU, leading to reduced inflammation and diminished tissue damage. Treatment with sEVs-CD73 results in a decreased proportion of Th1 cells in the spleen, draining lymph nodes, and eyes, accompanied by an increased proportion of regulatory T-cells (Treg cells). In vitro assays further reveal that sEVs-CD73 inhibits T-cell proliferation, suppresses Th1 cells differentiation, and enhances Treg cells proportion. Conclusion Over-expression of CD73 on MSC-sEVs enhances their immunosuppressive effects in EAU, indicating that sEVs-CD73 has the potential as an efficient immunotherapeutic agent for autoimmune uveitis.
Assessing the interchangeability of keratometry measurements from four biometric devices in intraocular lens power calculations: insights into the predictive accuracy of five modern IOL formulas
Background Achieving accurate intraocular lens (IOL) power calculation is crucial for successful refractive outcomes in cataract surgery. This study aimed to evaluate the interchangeability of keratometry (K) values obtained from four biometric devices (IOLMaster 700, CASIA2, Pentacam, and iTrace) and assess the predictive accuracy of five modern IOL calculation formulas (Barrett Universal II, Cooke K6, EVO 2.0, Kane, and PEARL-DGS) when using K values from these different devices. Methods This prospective study included K values obtained from four biometric devices for use in five IOL power calculation formulas. Predictive accuracy was assessed using multiple statistical parameters, including standard deviation (SD), mean absolute error (MAE), median absolute error (MedAE) and root mean square absolute error (RMSAE). The interchangeability of devices was evaluated by comparing predictive outcomes across devices and formulas, with statistical analyses focusing on consistency and agreement. Results Predictive accuracy across the five IOL formulas was stable and showed no statistically significant differences when using keratometry measurements from the same biometric device. However, significant variability was noted when comparing K values from different devices using the same formula. The SS-OCT-based devices (IOLMaster 700 and CASIA2) showed higher consistency in predictive accuracy compared to Scheimpflug-based Pentacam and ray-tracing-based iTrace. Despite this inter-device variability, all five IOL formulas showed overall robust performance across different devices. Conclusions Our findings indicate that keratometry measurements from different biometric devices are not fully interchangeable. SS-OCT-based devices (IOLMaster 700 and CASIA2) provided superior consistency in refractive prediction accuracy. Therefore, clinicians should carefully select biometric device-formula combinations based on the specific measurement principles and desired refractive outcomes. Further research involving larger sample sizes, additional IOL types and biometric devices, as well as assessment of surgeon-related factors, is warranted to optimize refractive accuracy in cataract surgery.
Optical coherence tomography biomarkers as outcome predictors to guide dexamethasone implant use in patients with iERM: a randomized controlled trial
Background We aimed to investigate the anatomical features of optical coherence tomography (OCT) and vitreous cytokine levels as predictors of outcomes of combined phacovitrectomy with intravitreal dexamethasone (DEX) implants for idiopathic epiretinal membrane (iERM) treatment. Methods A prospective, single-masked, randomized, controlled clinical trial included 48 eyes. They were randomly assigned in a 1:1 ratio to undergo the DEX group (combined phacovitrectomy with ERM peeling and Ozurdex implantation) and control group (phacovitrectomy only). Best-corrected visual acuity (BCVA) and central macular thickness (CMT) were assessed at 1 d, 1 week, 1 month, and 3 months. The structural features of OCT before surgery were analysed for stratified analysis. Baseline soluble CD14 (sCD14) and sCD163 levels in the vitreous fluid were measured using ELISA. Results BCVA and CMT were not significantly different in the DEX and control groups. Eyes with hyperreflective foci (HRF) at baseline achieved better BCVA ( P time*group =0.746; P group =0.043, Wald χ²=7.869) and lower CMT (Ptime*group = 0.079; Pgroup = 0.001, Wald χ²=6.774) responses to DEX during follow-up. In all patients, the mean vitreous level of sCD163 in eyes with HRF was significantly higher than that in eyes without HRF ( P  = 0.036, Z=-2.093) at baseline. In the DEX group, higher sCD163 predicted greater reduction in CMT from baseline to 1 month ( r  = 0.470, P  = 0.049). Conclusions We found that intraoperative DEX implantation did not have beneficial effects on BCVA and CMT over a 3-month period in all patients with iERM, implying that the use of DEX for all iERM is not recommended. In contrast, for those with HRF on OCT responded better to DEX implants at the 3-month follow-up and thier vitreous fluid expressed higher levels of sCD163 at baseline. These data support the hypothesis that DEX implants may be particularly effective in treating cases where ERM is secondary to inflammation. Trial registration The trail has been registered at Chinese Clinical Trail Registry( https://www.chictr.org.cn ) on 2021/03/12 (ChiCTR2100044228). And all patients in the article were enrolled after registration.
Mesenchymal-Stem-Cell-Based Strategies for Retinal Diseases
Retinal diseases are major causes of irreversible vision loss and blindness. Despite extensive research into their pathophysiology and etiology, pharmacotherapy effectiveness and surgical outcomes remain poor. Based largely on numerous preclinical studies, administration of mesenchymal stem cells (MSCs) as a therapeutic strategy for retinal diseases holds great promise, and various approaches have been applied to the therapies. However, hindered by the retinal barriers, the initial vision for the stem cell replacement strategy fails to achieve the anticipated effect and has now been questioned. Accumulating evidence now suggests that the paracrine effect may play a dominant role in MSC-based treatment, and MSC-derived extracellular vesicles emerge as a novel compelling alternative for cell-free therapy. This review summarizes the therapeutic potential and current strategies of this fascinating class of cells in retinal degeneration and other retinal dysfunctions.