Trends in the biological functions and medical applications of extracellular vesicles and analogues

Natural extracellular vesicles (EVs) play important roles in many life processes such as in the intermolecular transfer of substances and genetic information exchanges. Investigating the origins and working mechanisms of natural EVs may provide an understanding of life activities, especially regarding the occurrence and development of diseases. Additionally, due to their vesicular structure, EVs (in small molecules, nucleic acids, proteins, etc.) could act as efficient drug-delivery carriers. Herein, we describe the sources and biological functions of various EVs, summarize the roles of EVs in disease diagnosis and treatment, and review the application of EVs as drug-delivery carriers. We also assess the challenges and perspectives of EVs in biomedical applications.

Effects of angiotensin II receptor blocker usage on viral load, antibody dynamics, and transcriptional characteristics among COVID-19 patients with hypertension / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Epidemiological evidence suggests that patients with hypertension infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are at increased risk of acute lung injury. However, it is still not clear whether this increased risk is related to the usage of renin-angiotensin system (RAS) blockers. We collected medical records of coronavirus disease 2019 (COVID-19) patients from the First Affiliated Hospital, Zhejiang University School of Medicine (Hangzhou, China), and evaluated the potential impact of an angiotensin II receptor blocker (ARB) on the clinical outcomes of COVID-19 patients with hypertension. A total of 30 hypertensive COVID-19 patients were enrolled, of which 17 were classified as non-ARB group and the remaining 13 as ARB group based on the antihypertensive therapies they received. Compared with the non-ARB group, patients in the ARB group had a lower proportion of severe cases and intensive care unit (ICU) admission as well as shortened length of hospital stay, and manifested favorable results in most of the laboratory testing. Viral loads in the ARB group were lower than those in the non-ARB group throughout the disease course. No significant difference in the time of seroconversion or antibody levels was observed between the two groups. The median levels of soluble angiotensin-converting enzyme 2 (sACE2) in serum and urine samples were similar in both groups, and there were no significant correlations between serum sACE2 and biomarkers of disease severity. Transcriptional analysis showed 125 differentially expressed genes which mainly were enriched in oxygen transport, bicarbonate transport, and blood coagulation. Our results suggest that ARB usage is not associated with aggravation of COVID-19. These findings support the maintenance of ARB treatment in hypertensive patients diagnosed with COVID-19.

Study on the serotype, drug sensitivity and virulence genes of clinical isolates of Salmonella in Zhejiang Province / 中华传染病杂志

Objective:To investigate the serotype distribution, drug resistance and the virulence gene profiles of clinical isolates of Salmonella in Zhejiang Province. Methods:A retrospective study of 463 clinical isolates of Salmonella in nine regions of Zhejiang Province from 2010 to 2017 was conducted. Their serotypes were detected using the Kauffmann-White scheme based on serological detection. Antibiotics susceptibility tests were carried out using K-B disk diffusion method. Eleven virulence genes were detected by polymerase chain reaction. Results:A total of 35 serotypes were identified among the 463 strains of Salmonella. The dominant serotypes were Salmonella typhimurium (41.90%(194/463)) and Salmonella enteritis (22.25%(103/463)). The resistance rate of Salmonella to ampicillin was the highest (66.52%(308/463)), followed by ampicillin/sulbactam (46.87%(217/463)), while low resistance rate to piperacillin/tazobactam was observed (3.24%(15/463)). All strains were sensitive to imipenem and meropenem. Finally, 188 strains (40.60%) of multi-drug resistance were found. The virulence genes hilA, ssrB, marT, siiD, sopB and pagN were found in all Salmonella strains. The virulence gene vexA was found only in Salmonella typhi and Salmonella Dublin; virulence gene icmF was mainly found in Salmonella enteritis. The virulence plasmid gene spvB and pefA were mainly found in Salmonella enteritidis and Salmonella typhimurium and invariably appeared in pairs. The virulence gene cdtB was mainly found in Salmonella typhi and Salmonella paratyphi A. Conclusions:Salmonella typhimurium and Salmonella enteritis are the main clinically isolated Salmonella strains in Zhejiang Province. The situation of multi-drug resistance is severe and a variety of virulence genes are highly detected.

Intervention of Shenhongtongluo Granules on inflammatory response and oxidative stress of atherosclerosisin rabbit / 国际生物医学工程杂志

Objective To study the effects of ShenhongTongluo Granules on blood lipids, inflammatory related factors and oxidative stress-related indexes in rabbit atherosclerosis model, and to explore the mechanism of Shenhongtongluo Granules on atherosclerosis. Methods 70 healthy male New Zealand white rabbits were randomly divided into blank control group, model group, aspirin combined with simvastatin group, aspirin group, simvastatin group, Shenhongtongluo Granule prevention group, and Shenhongtongluo Granule treatment group. The rabbit atherosclerosis model was established by lipidforage diet combined with immune stimulation, and the blank group was fed with commonforage. The Shenhongtongluo Granule prevention group was given Shenhongtongluo Granule at the beginning of modeling, and the other intervention groups were given the corresponding drugs after the successful modeling. Before and after modeling, lipid changes were checked in each group, including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), superoxide dismutase activity (SOD) and malondialde-hyde (MDA) in the serum. The aorta of the model group was separated and oil red O staining was performed to observe the pathological and morphological changes of the aorta. Western blotting and reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of Nox4 and p22phox. Western blotting was used to detect the expression of TLR4 and NF-κB protein in aorta. Results Twelve weeks after modeling, atheromatous plaques were obviously observed on the aorta stained with oil red O, indicating successful atherosclerosis modeling. Compared with the blank control group, TC, TG, and LDL-C in the serum of the atherosclerosis model group were significantly increased (all P<0.05). Compared with the model group, the atherosclerotic plaques in the Shenhongtongluo Granule prevention and the treatment groups were significantly reduced , the levels of TC , TG , LDL-C in serum were decreased, and the levels of SOD were increased, and MDA levels were reduced (all P<0.05). The expressions of TLR4, NF-κB, Nox4, and p22phox in the aorta of Shenhongtongluo Granule prevention group were significantly reduced (all P<0.05). Conclusions Shenhongtongluo Granules can inhibit the formation of atheromatous plaques, have a good effect on regulating blood lipids, and can improve the ability of anti-oxidative stress, and have a good preventive and therapeutic effect.

Dynamic changes in blood flow and function of the heart using 13N-NH3 PET gated myocardial perfusion imaging in Beagle dogs after local heart irradiation / 中华核医学与分子影像杂志

Objective To investigate the value of local myocardial blood flow and myocardial function parameters in monitoring the dynamic changes of radiation induced heart disease (RIHD) using 13NNH3 PET gated myocardial perfusion imaging(GMPI).Methods Six healthy male Beagle dogs underwent 13N-NH3 PET GMPI 1 week before irradiation and 3,6 and 12 months after irradiation in the anterior wall of the left ventricle with a single dose of 20 Gy.Global myocardial function parameters including left ventricular ejection fraction (LVEF),end-diastolic volume (EDV),end-systolic volume (ESV),and regional myocardial function parameters including wall motion (WM),wall thickening (WT),end-diastolic perfusion (EDP),end-systolic perfusion (ESP) before and after irradiation were compared by repeated measures analysis of variance and paired t test.Results There were no significant changes between EDV,ESV and LVEF at baseline and those at 3 months after irradiation.EDV at 6 months after irradiation still had no change,compared with baseline value and EDV at 3 months after irradiation,but ESV was increased and LVEF was decreased.Twelve months after irradiation,ESV was further expanded,LVEF was further reduced,and EDV began to increase (F values:20.974-177.846,all P＜0.05).Compared with the baseline,WM,WT,EDP and ESP were increased in 10％(2/20),20％(4/20),10％(2/20) and 15％(3/20) of myocardial segments at 3 months after irradiation (t values:14.446-672.315,all P＜0.05);those parameters were decreased in 15％(3/20),20％(4/20),15％(3/20) and 25％(5/20) of myocardial segments at 6 months after irradiation (t values:18.171-723.156,all P＜0.05),and were decreased in 35％(7/20),45％(9/20),40％(8/20) and 60％ (12/20) of myocardial segments at 12 months after irradiation (t values:14.783-711.259,all P＜0.05).Conclusions 13N-NH3 PET GMPI could be used to detect RIHD early and monitor the dynamic development of RIHD.Compared with the global left ventricular function parameters,regional myocardial function parameters (WM,WT,EDP and ESP) are more sensitive,which may be served as the early monitoring indicators for RIHD.

Correlation between white blood cell count to mean platelet volume ratio and short-term prognosis of large artery atherosclerotic stroke / 国际脑血管病杂志

Objective To investigate the correlation between white blood cell count to mean platelet volume ratio (WMR) in peripheral blood and short-term prognosis of large artery atherosclerotic stroke (LAA).Methods From March 2015 to March 2018,patients with acute ischemic stroke admitted to the Department of Neurology,the Second Hospital of Tianjin Medical University were enrolled retrospectively.According to the TOAST etiological classification criteria,they were divided into LAA group and non-LAA group.According to the modified Rankin scale (mRS) score at 14 d after onset,they were divided into short-term good outcome group (0-2) and short-term poor outcome group (＞2).The clinical data,routine laboratory results and WlMR were collected and compared.Multivariatelogistic regression analysis was used to determine the independent risk factors for LAA and its short-term poor outcome.Receiver operating characteristic (ROC) curve was used to evaluate the predictive value of WMR for LAA short-term poor outcome.Results A total of 873 patients with acute ischemic stroke were enrolled,including 447 in the LAA group and 400 in the non-LAA group.WMR in the LAA group was significantly higher than that in the nonLAA group (0.96 ±0.16 vs.0.94 ±0.05;t =-2.397,P =0.017).Multivariate logistic regression analysis showed that WMR was not an independent risk factor for LAA (odds ratio 1.150,95％ confidence interval 0.999-1.325;P =0.052).WMR in the LAA short-term poor outcome group was significantly higher than that in the LAA short-term good outcome group (1.04 ± 0.129 vs.0.87 ± 0.146;t =-13.338,P ＜ 0.001).Multivariate logistic regression showed that WMR was an independent risk factor for LAA shortterm poor outcome (odds ratio 1.242,95％ confidence interval 1.025-1.504;P=0.027).ROC curve analysis showed that the optimal cutoff value of WMR in predicting LAA short-term poor outcome was 0.89,the area under the curve (AUC) was 0.799 (95％ confidence interval 0.755-0.843),the sensitivity was 85％,the specificity was 77.7％,the positive predictive value was 74.04％,and the negative predictive value was 86.93％.Conclusion The increased level of WMR are not independent risk factor for LAA,but are independent associated with poor short-term outcomes in LAA.

Optimization of N2a cell transfection mediated by liposome / 中国组织工程研究

BACKGROUND:Cationic liposome-mediated celltransfection is reliable and repeatable. However the transfection efficiency is often low. OBJECTIVE:To study the optimized methods for gene transfection mediated by liposome into N2a cells (mouse neuroblastma cells). METHODS:Using traditional adherent method and improved suspension method, 500 ng recombinant plasmid pcDNA3-GFP carrying green fluorescence protein was transfected into N2a cells in 24-wel culture plate, which was mediated by 1.5μL Lipofectamine?LTX Reagent. The expression of green fluorescent protein was observed by inverted fluorescence microscope, and the transfection efficiencies at different transfection ways were calculated. By using improved suspension transfection method, 500 ng plasmid DNA was transfected with different doses of Lipofectamine?LTX Reagent (1.0, 1.5, 2.0, 2.5μL). The optimal ratio of liposome and DNA was explored. RESULTS AND CONCLUSION:The transfection efficiency of suspension transfection method was significantly higher than that of the tranditional adherent method (P<0.01) when using 1.5μL liposome/500 ng DNA. The transfection efficiency of the 1.0, 1.5, 2.0, 2.5μL Lipofectamine?LTX on 500 ng plasmid DNA was respectively (76.60±3.85)%, (80.00±4.17)%, (88.00±5.89)%, (54.96±4.23)%. It showed the 500 ng DNA and 2.0μL liposome achieve the highest transfection efficiency.