Characterization of SARS-CoV-2 variants B.1.617.1 (Kappa), B.1.617.2 (Delta) and B.1.618 on cell entry, host range, and sensitivity to convalescent plasma and ACE2 decoy receptor

Recently, highly transmissible SARS-CoV-2 variants B.1.617.1 (Kappa), B.1.617.2 (Delta) and B.1.618 were identified in India with mutations within the spike proteins. The spike protein of Kappa contains four mutations E154K, L452R, E484Q and P681R, and Delta contains L452R, T478K and P681R, while B.1.618 spike harbors mutations {Delta}145-146 and E484K. However, it remains unknown whether these variants have altered in their entry efficiency, host tropism, and sensitivity to neutralizing antibodies as well as entry inhibitors. In this study, we found that Kappa, Delta or B.1.618 spike uses human ACE2 with no or slightly increased efficiency, while gains a significantly increased binding affinity with mouse, marmoset and koala ACE2 orthologs, which exhibits limited binding with WT spike. Furthermore, the P618R mutation leads to enhanced spike cleavage, which could facilitate viral entry. In addition, Kappa, Delta and B.1.618 exhibits a reduced sensitivity to neutralization by convalescent sera owning to the mutation of E484Q, T478K, {Delta}145-146 or E484K, but remains sensitive to entry inhibitors-ACE2-lg decoy receptor. Collectively, our study revealed that enhanced human and mouse ACE2 receptor engagement, increased spike cleavage and reduced sensitivity to neutralization antibodies of Kappa, Delta and B.1.618 may contribute to the rapid spread of these variants and expanded host range. Furthermore, our result also highlighted that ACE2-lg could be developed as broad-spectrum antiviral strategy against SARS-CoV-2 variants.

Mutation Y453F in the spike protein of SARS-CoV-2 enhances interaction with the mink ACE2 receptor for host adaption

COVID-19 patients transmitted SARS-CoV-2 to minks in the Netherlands in April 2020. Subsequently, the mink-associated virus (miSARS-CoV-2) spilled back over into humans. Genetic sequences of the miSARS-CoV-2 identified a new genetic variant known as "Cluster 5" that contained mutations in the spike protein. However, the functional properties of these "Cluster 5" mutations have not been well established. In this study, we found that the Y453F mutation located in the RBD domain of miSARS-CoV-2 is an adaptive mutation that enhances binding to mink ACE2 and other orthologs of Mustela species without compromising, and even enhancing, its ability to utilize human ACE2 as a receptor for entry. Structural analysis suggested that despite the similarity in the overall binding mode of SARS-CoV-2 RBD to human and mink ACE2, Y34 of mink ACE2 was better suited to interact with a Phe rather than a Tyr at position 453 of the viral RBD due to less steric clash and tighter hydrophobic-driven interaction. Additionally, the Y453F spike exhibited resistance to convalescent serum, posing a risk for vaccine development. Thus, our study suggests that since the initial transmission from humans, SARS-CoV-2 evolved to adapt to the mink host, leading to widespread circulation among minks while still retaining its ability to efficiently utilize human ACE2 for entry, thus allowing for transmission of the miSARS-CoV-2 back into humans. These findings underscore the importance of active surveillance of SARS-CoV-2 evolution in Mustela species and other susceptible hosts in order to prevent future outbreaks.

Self-assessment of COVID-19 vaccination efficacy using a simple POCT for SARS-CoV-2 S1 protein antibody IgG-IgM

BackgroundMore than ten novel COVID-19 vaccines have been approved with protections against SARS-CoV-2 infections ranges between 52-95%. It is of great interest to the vaccinees who have received the COVID-19 vaccines, vaccine developers and authorities to identify the non-responders in a timely manner so intervention can take place by either giving additional boosts of the same vaccine or switching to a different vaccine to improve the protection against the SARS-CoV-2 infections. A robust correlation was seen between binding antibody titer and efficacy (p=0.93) in the clinic studies of 7 COVID-19 vaccines, so it is of urgency to develop a simple POCT for vaccinees to self-assess their immune response at home. MethodsUsing CHO cell-expressed full length SARS-CoV2 S1 protein as coating antigen on colloidal gold particles, a SARS-CoV-2 S1 IgG-IgM antibody lateral flow test kit (POCT) was developed. The test was validated with negative human sera collected prior to the COVID-19 outbreaks, and blood samples from human subjects prior, during, and post-immunization of COVID-19 vaccines. ResultsThe specificity of the POCT was 99.0%, as examined against 947 normal human sera and 20 whole blood samples collected pre-immunization. The limit of detection was 50 IU/mL of pseudovirus neutralizing titer (PVNT) using human anti-SARS-2 neutralizing standards from convalescent sera. The sensitivity of POCT for SARS-CoV-2 S1 protein antibody IgG-IgM was compared with SARS-CoV-2 RBD antibody ELISA and determined to be 100% using 23 blood samples from vaccinated human subjects and 10 samples from non-vaccinated ones. Whole blood samples were collected from 119 human subjects (ages between 22-61 years) prior to, during, and post-vaccination of five different COVID-19 vaccines. Among them, 115 people tested positive for SARS-CoV-2 S1 antibodies (showing positive at least once) and 4 people tested negative (tested negative at least twice on different days), demonstrating 96.64% of seroconversion after full-vaccination. 92.3% (36/39) of the human subjects who were younger than 45 achieved seroconversion within 2 weeks while only 57.1% (4/7) of subjects older than 45 tested positive for S1 antibodies, suggesting that younger people develop protection much faster than older ones. Even though the S1 antibody level in 88% of human subjects vaccinated with inactivated virus dropped below 50 IU/mL two months later, one boost could quickly raise the S1 antibody titer above 50 IU/mL of PVNT, indicates that the initial vaccination was successful and immunization memory was developed. ConclusionUsing the lateral flow tests of SARS-CoV2 S1 IgG+IgM, vaccinated human subjects can easily self-assess the efficacy of their vaccination at home. The vaccine developer could quickly identify those non-responders and give them an additional boost to improve the efficacy of their vaccines. Vaccinees who failed in response could switch to different types of COVID-19 vaccines since there are more than 10 COVID-19 vaccines approved using three different platform technologies. HighlightsO_LIMore than ten novel COVID-19 vaccines have been approved with protections against SARS-CoV-2 infections ranges between 52-95%. It is of great interest to the vaccinees who have received the COVID-19 vaccines, vaccine developers and authorities to identify the non-responders in a timely manner. C_LIO_LIA highly specific and very simple lateral flow test kit for measurement of SARS-CoV-2 S1IgG+IgM antibodies post-immunization of COVID-19 vaccine using peripheral blood was developed as a home-test assay with a limit of detection (LOD) at 50 IU/mL of pseudovirus neutralizing titer (PVNT). C_LIO_LIAfter full vaccinations with COVID-19 vaccines, 96.6% of the volunteers successfully achieved the seroconversion of SARS-CoV-2 S1 IgG+IgM antibody. C_LIO_LI92.3% (36/39) of the human subjects who were younger than 45 achieved seroconversion within 2 weeks while only 57.1% (4/7) of subjects older than 45 tested positive for S1 antibodies, suggesting that younger people develop protection much faster than older ones. C_LIO_LIEven though the S1 antibody level in 88% of human subjects vaccinated with inactivated virus dropped below the detection 2-6 months later, one boost could quickly raise the S1 antibody titer above 50 IU/mL of PVNT, indicating that the initial vaccination was successful and immunization memory was developed. C_LI

Susceptibilities of human ACE2 genetic variants in coronavirus infection

The COVID-19 pandemic, caused by SARS-CoV-2, has resulted in more than 1603 million cases worldwide and 3.4 million deaths (as of May 2021), with varying incidences and death rates among regions/ethnicities. Human genetic variation can affect disease progression and outcome, but little is known about genetic risk factors for SARS-CoV-2 infection. The coronaviruses SARS-CoV, SARS-CoV-2 and HCoV-NL63 all utilize the human protein angiotensin-converting enzyme 2 (ACE2) as the receptor to enter cells. We hypothesized that the genetic variability in ACE2 may contribute to the variable clinical outcomes of COVID-19. To test this hypothesis, we first conducted an in silico investigation of single-nucleotide polymorphisms (SNPs) in the coding region of ACE2 gene. We then applied an integrated approach of genetics, biochemistry and virology to explore the capacity of select ACE2 variants to bind coronavirus spike protein and mediate viral entry. We identified the ACE2 D355N variant that restricts the spike protein-ACE2 interaction and consequently limits infection both in vitro and in vivo. In conclusion, ACE2 polymorphisms could modulate susceptibility to SARS-CoV-2, which may lead to variable disease severity.

Spike mutations in SARS-CoV-2 variants confer resistance to antibody neutralization

New SARS-CoV-2 variants continue to emerge from the current global pandemic, some of which can replicate faster and with greater transmissibility and pathogenicity. In particular, UK501Y.V1 identified in UK, SA501Y.V2 in South Africa, and BR501Y.V3 in Brazil are raising serious concerns as they spread quickly and contain spike protein mutations that may facilitate escape from current antibody therapies and vaccine protection. Here, we constructed a panel of 28 SARS-CoV-2 pseudoviruses bearing single or combined mutations found in the spike protein of these three variants, as well as additional nine mutations that within or close by the major antigenic sites in the spike protein identified in the GISAID database. These pseudoviruses were tested against a panel of monoclonal antibodies (mAbs), including some approved for emergency use to treat SARS-CoV-2 infection, and convalescent patient plasma collected early in the pandemic. SA501Y.V2 pseudovirus was the most resistant, in magnitude and breadth, against mAbs and convalescent plasma, followed by BR501Y.V3, and then UK501Y.V1. This resistance hierarchy corresponds with Y144del and 242-244del mutations in the N-terminal domain as well as K417N/T, E484K and N501Y mutations in the receptor binding domain (RBD). Crystal structural analysis of RBD carrying triple K417N-E484K-N501Y mutations found in SA501Y.V2 bound with mAb P2C-1F11 revealed a molecular basis for antibody neutralization and escape. SA501Y.V2 and BR501Y.V3 also acquired substantial ability to use mouse and mink ACE2 for entry. Taken together, our results clearly demonstrate major antigenic shifts and potentially broadening the host range of SA501Y.V2 and BR501Y.V3, which pose serious challenges to our current antibody therapies and vaccine protection.

A novel cell culture system modeling the SARS-CoV-2 life cycle

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the global pandemic of COVID-19, and no effective antiviral agents and vaccines are available. SARS-CoV-2 is classified as a biosafety level-3 (BLS-3) agent, impeding the basic research into its biology and the development of effective antivirals. Here, we developed a biosafety level-2 (BSL-2) cell culture system for production of transcription and replication-competent SARS-CoV-2 virus-like-particles (trVLP). This trVLP expresses a reporter gene (GFP) replacing viral nucleocapsid gene (N), which is required for viral genome packaging and virion assembly (SARS-CoV-2-GFP/{Delta}N trVLP). The complete viral life cycle can be achieved and exclusively confined in the cells ectopically expressing SARS-CoV or SARS-CoV-2 N proteins, but not MERS-CoV N. Genetic recombination of N supplied in trans into viral genome was not detected, as evidenced by sequence analysis after one-month serial passages in the N-expressing cells. Moreover, intein-mediated protein trans-splicing approach was utilized to split the viral N gene into two independent vectors, and the ligated viral N protein could function in trans to recapitulate entire viral life cycle, further securing the biosafety of this cell culture model. Based on this BSL-2 SARS-CoV-2 cell culture model, we developed a 96-well format high throughput screening for antivirals discovery. We identified salinomycin, tubeimoside I, monensin sodium, lycorine chloride and nigericin sodium as potent antivirals against SARS-CoV-2 infection. Collectively, we developed a convenient and efficient SARS-CoV-2 reverse genetics tool to dissect the virus life cycle under a BSL-2 condition. This powerful tool should accelerate our understanding of SARS-CoV-2 biology and its antiviral development.

Comparative analysis reveals the species-specific genetic determinants of ACE2 required for SARS-CoV-2 entry

Coronavirus interaction with its viral receptor is a primary genetic determinant of host range and tissue tropism. SARS-CoV-2 utilizes ACE2 as the receptor to enter host cell in a species-specific manner. We and others have previously shown that ACE2 orthologs from New World monkey, koala and mouse cannot interact with SARS-CoV-2 to mediate viral entry, and this defect can be restored by humanization of the restrictive residues in New World monkey ACE2. To better understand the genetic determinants behind the ability of ACE2 orthologs to support viral entry, we compared koala and mouse ACE2 sequences with that of human and identified the key residues in koala and mouse ACE2 that restrict viral receptor activity. Humanization of these critical residues rendered both koala and mouse ACE2 capable of binding the spike protein and facilitating viral entry. The single mutation that allowed for mouse ACE2 to serve as a viral receptor provides a potential avenue for the development of SARS-CoV-2 mouse model.

Recombinant SARS-CoV-2 spike S1-Fc fusion protein induced high levels of neutralizing responses in nonhuman primates

The COVID-19 outbreak has become a global pandemic responsible for over 2,000,000 confirmed cases and over 126,000 deaths worldwide. In this study, we examined the immunogenicity of CHO-expressed recombinant SARS-CoV-2 S1-Fc fusion protein in mice, rabbits, and monkeys as a potential candidate for a COVID-19 vaccine. We demonstrate that the S1-Fc fusion protein is extremely immunogenic, as evidenced by strong antibody titers observed by day 7. Strong virus neutralizing activity was observed on day 14 in rabbits immunized with the S1-Fc fusion protein using a pseudovirus neutralization assay. Most importantly, in less than 20 days and three injections of the S1-Fc fusion protein, two monkeys developed higher virus neutralizing titers than a recovered COVID-19 patient in a live SARS-CoV-2 infection assay. Our data strongly suggests that the CHO-expressed SARS-CoV-2 S1-Fc recombinant protein could be a strong candidate for vaccine development against COVID-19. HighlightsO_LICHO-expressed S1-Fc protein is very immunogenic in various animals and can rapidly induce strong antibody production C_LIO_LIS1-Fc protein solicits strong neutralizing activities against live virus C_LIO_LIStable CHO cell line expressing 50 mg/L of S1-Fc and a 3,000 L Bioreactor can produce 3 million doses of human COVID-19 vaccine every 10 days, making it an accessible and affordable option for worldwide vaccination C_LI

Functional and Genetic Analysis of Viral Receptor ACE2 Orthologs Reveals Broad Potential Host Range of SARS-CoV-2

The pandemic of Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a major global health threat. Epidemiological studies suggest that bats are the natural zoonotic reservoir for SARS-CoV-2. However, the host range of SARS-CoV-2 and intermediate hosts that facilitate its transmission to humans remain unknown. The interaction of coronavirus with its host receptor is a key genetic determinant of host range and cross-species transmission. SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) as the receptor to enter host cells in a species-dependent manner. It has been shown that human, palm civet, pig and bat ACE2 can support virus entry, while the murine ortholog cannot. In this study, we characterized the ability of ACE2 from diverse species to support viral entry. We found that ACE2 is expressed in a wide range of species, with especially high conservation in mammals. By analyzing amino acid residues of ACE2 critical for virus entry, based on structure of SARS-CoV spike protein interaction with human, bat, palm civet, pig and ferret ACE2, we identified approximately eighty ACE2 proteins from mammals that could potentially mediate SARS-CoV-2 entry. We chose 48 representative ACE2 orthologs among eighty orthologs for functional analysis and it showed that 44 of these mammalian ACE2 orthologs, including those of domestic animals, pets, livestock, and animals commonly found in zoos and aquaria, could bind SARS-CoV-2 spike protein and support viral entry. In contrast, New World monkey ACE2 orthologs could not bind SARS-CoV-2 spike protein and support viral entry. We further identified the genetic determinant of New World monkey ACE2 that restricts viral entry using genetic and functional analyses. In summary, our study demonstrates that ACE2 from a remarkably broad range of species can facilitate SARS-CoV-2 entry. These findings highlight a potentially broad host tropism of SARS-CoV-2 and suggest that SARS-CoV-2 might be distributed much more widely than previously recognized, underscoring the necessity to monitor susceptible hosts to prevent future outbreaks.

Serological diagnostic kit of SARS-CoV-2 antibodies using CHO-expressed full-length SARS-CoV-2 S1 proteins

WHO has declared COVID-19 a pandemic with more than 300,000 confirmed cases and more than 14,000 deaths. There is urgent need for accurate and rapid diagnostic kits. Here we report the development and validation of a COVID-19/SARS-CoV-2 S1 serology ELISA kit for the detection of total anti-virus antibody (IgG+IgM) titers in sera from either the general population or patients suspected to be infected. For indirect ELISA, CHO-expressed recombinant full length SARS-CoV-2-S1 protein with 6* His tag was used as the coating antigen to capture the SARS-CoV-2-S1 antibodies specifically. The specificity of the ELISA kit was determined to be 97.5%, as examined against total 412 normal human sera including 257 samples collected prior to the outbreak and 155 collected during the outbreak. The sensitivity of the ELISA kit was determined to be 97.5% by testing against 69 samples from hospitalized and/or recovered COVID-19 patients. The overall accuracy rate reached 97.3%. Most importantly, in one case study, the ELISA test kit was able to identify an infected person who had previously been quarantined for 14 days after coming into contact with a confirmed COVID-19 patient, and discharged after testing negative twice by nucleic acid test. With the assays developed here, we can screen millions of medical staffs in the hospitals and people in residential complex, schools, public transportations, and business parks in the epidemic centers of the outbreaks to fish out the "innocent viral spreaders", and help to stop the further spreading of the virus.

Generation of antibodies against COVID-19 virus for development of diagnostic tools

The COVID-19 China coronavirus started in Dec 2019 was challenged by the lack of accurate serological diagnostic tool for this deadly disease to quickly identify and isolate the infected patients. The generation of COVID-19-specific antibodies is essential for such tasks. Here we report that polyclonal and monoclonal antibodies were generated by immunizing animals with synthetic peptides corresponding to different areas of Nucleoprotein (N) of COVID-19. The specificities of the COVID-19 antibodies were assessed by Western Blot analysis against NPs from COVID-19, MERS and SARS. Antibodies were used for immunohistochemistry staining of the tissue sections from COVID-19 infected patient, as a potential diagnostic tool. A Sandwich ELISA kit was quickly assembled for quantitation of the virus/NP of COVID-19 concentrations in the vaccine preparations. Development of POCT is also aggressively undergoing.

Compliance of secondary prevention in patients with coronary artery disease post coronary revascularization / 中华全科医师杂志

Objective To investigate the compliance status of secondary prevention in patients with coronary artery disease (CAD) following revascularization.MethodsA total of 512 patients with CAD who received procedures for coronary revascularization were enrolled in the study from January 2009 to October 2010,including 472 cases of percutaneous coronary intervention stenting,25 cases of coronary artery bypass grafting and 15 cases of stenting plus bypass.The demographic information,prophylactic drug therapies, lifestylechangesandmodifiableriskfactorsweresurveyedwithquestionnaires,anthroposomatologicalmeasurementsandlaboratorytestsinpatients3monthsaftercoronary revascularization.ResultsThe proportion of patients on statins,aspirin,β-blockers,angiotensin-converting enzymeinhibitors/angiotensinreceptorblockers(ACEIs/ARBs)andinfluenzavaccinationwere 81.4％ (417/512),93.9％ ( 481/512 ),82.0％ ( 420/512 ),76.2％ ( 390/512 ) and 3.7％ ( 19/512 ) respectively.Based on the criteria recommended by the American Heart Association/American College of Cardiology (AHA/ACC)Guidelines for Secondary Prevention for Patients with Coronary and Other Atherosclerotic Vascular Disease: 2006 Update, the percentages of achieving therapeutic targets of modifiable risk factor management were as follows:glycosylated hemoglobin (90.2％,462/512 ),total cholesterol ( 68.6％,351/512 ),triglycerides ( 58.8％,301/512 ),high-density lipoprotein cholesterol ( 91.6％,469/512 ),low-density lipoprotein cholesterol ( 44.5 ％,228/512 ),systolic pressure ( 75.2 ％,385/512 ) and diastolic pressure (90.4％,463/512 ) respectively.And the proportions of improved lifestyle were as follows:smoking cessation/non-smoking 81.4％ (417/512),diet control 78.5％ ( 402/512 ),achieving weight targets 61.7％ (316/512)and regular exercise 58.2％ (298/512).ConclusionsThere is a relatively high percentage of standardized antiplatelet therapy and continuous statins medication in patients with coronary artery disease following revascularization. However,many significant modifiable risk factors have not been controlled optimally and lifestyle of patients needs further improvement. There is still a considerable scope for further improvement of secondary prevention in this group of patients.

The effect of different dosage of aspirin on inflammatory biomarkers and prognosis in acute coronary syndrome / 中华内科杂志

Objective To observe and assess the effect of different dosages of aspirin on inflammatory biomarkers, hemorheology (platelet aggregation rate) and clinical prognosis in patients with acute coronary syndrome ( ACS). Methods ACS patients were randomly assigned to receive different dosages of aspirin treatment orally. Patients in group A,B and C took 100 mg, 500 mg and 1000 mg of aspirin per day respectively. They were treated and followed-up for 1 year. High-sensitivity C-reactive protein ( hsCRP) , IL-6, tumor necrosis TNFot and platelet aggregation rate were examined and major adverse cardiac events( MACE) were recorded. Results A total of 312 patients with ACS were enrolled in the study. The baseline characteristics of the three groups were not different with respect to age, gender, cardiovascular risk profile, level of inflammatory biomarkers and concomitant treatment before and after randomization. The levels of baseline serum hsCRP, IL-6 and TNFa were higher in subjects of the study as compared with normal reference value (P<0. 05, <0. 05, <0. 01) and they decreased significantly after therapy with 3 different doses of aspirin (detected at 30 days, 6 months and 12 months, P <0. 001 ) , but there were no significant differences among the three groups( P >0. 05) . Rehospitalization , MACE and the change of platelet aggregation ratio were not significantly different among the three groups. The incidence of gastrointestinal complaints was significantly higher in groups B and C than in group A ( P < 0. 05 ). Conclusions The levels of serum inflammatory biomarker increase in patients with ACS. Aspirin therapy may decrease the level of inflammatory markers significantly, but increasing the dosage of aspirin from 100 mg to 1000 mg daily does not decrease the level of inflammatory markers and the clinical MACEs further. However, the incidence of gastrointestinal complaints increase significantly with the increase of aspirin dosage.

Influence of valsartan-eluting stent implantation into rabbit abdominal aorta on collagen deposition and AT2 receptor expression / 中国组织工程研究

BACKGROUND:Clinical trials have shown that oral administration of valsartan can decrease in-stent restenosis after stent implantation.But whether valsartan used locally also has the sanle effect and the possible mechanism should be validated.OBJECTIVE:To observe the effect of valsartan-eluting stents on collagen deposition in neointima and AT2 receptor expression after implanting valsartan-eluting stents into rabbit abdominal orta.DESIGN:Randomized and controlled animal experiment.SETTING:Beijing Friendship Hospital.MATERIALS:The experiment was performed at the Laboratory of Beijing Friendship Hospital between October 2004 and March 2006.Fifteen New Zealand white rabbits,irrespective of gender,weighing 2.75-3.25 kg were selected(Animal Laboratory of Beijing Friendship Hospital).The rabbits were adaptively fed for one week.All the operations of rabbits during the experiment were accorded with animal ethical standards.Valsartan powder was presented as a gift by Novartis.China;Reagent of MASSON was provided by Department of Pathology of Beijing Friendship Hospital;1%picrosirius solution was provided by the Department of Pathology of China-Japan Friendship Hospital:Mice-anti-rabbit monoclonal AT2 antibody was product of Santa Cruz Biotechnology (USA);Envision reagent was purphased from Dako;primers were synthesized by SBS Genetech(SBS).METHODS:①The animals were randomized into bare-metal stent group,carrier-eluting stent group and valsartan-eluting stent group with 5 animals in each group.All rabbits were implanted with corresponding types of above-mentioned stents into abdominal aortas down below renal artery.②Quantitative angiography before,immediately after and 3 months after stent implantation were performed to compare vascular diameters of the aortas.③Three months Iater,the rabbits were executed after anaesthesia.The vessels with stents were processed with HE staining.Indices of the vascular neointimal formation,I.e. iBrier and external elastic membrane luminal area,the maximal intimal thickness,neointimal area and stenosis area percent were measured.④The collagen deposition in neointima was observed through MASSON staining,and the type of collagen was identified through picrosirius stain.⑤The expressions of AT2R mRNA and proteins were also compared by RT-PCR and immunohistochemistry among three groups.MAIN OUTCOME MEASURES:①The diameters of aorta with stent at different time;②Inner and extemal elastic membrane luminal area,the maximal intimal thickness,neointimal area and stenosis area percent;③Collagen deposition and type of collagen of the aorta with stent;④AT2R mRNA and protein expressions.RESULTS:Of 15 rabbits selected in the experiment,1 rabbit of the bare-metal stent group died during stent implanting,and 1 of the carrier-eluting stent group died during breeding after stenting.Finally,13 rabbits were included in final analysis.①There were no significant differences in the mean aortic diameters between any two of the three groups before,immediately after and 3 months after stent implantation(P＞0.05).②A larger 1uminal area and a less neointimal hyperplasia in valsartan eluting-stents group were found compared with the other two groups(P＜0.01).③MASSON staining showed that collagen deposition was rich in neointima of bare-metal stent group and carrier-eluting stent group while rare in neointima of valsartan eluting stent group.Pierosirius staining suggested that the deposited collagen was type Ⅲ collagen predominantly accompanied by type Ⅰ collagen around stents struts;the type Ⅲcollagen deposition was obviously decreased in valsartan eluting stent group.④AT2R protein only expressed in adventitia of bare-metal stet group and arrier-eluting stent group while expressed in all layers of valsartan eluting-stents group.The AT2R mRNA/a-Actin mRNA of valsartan eluting stent group was significantly higher than that in the other two groups(P＜0.01).CONCLUSION:Valsartan eluting-stents inhibits neointimal hyperplasia after stenting by decreasing collagen deposition.especially collagen Ⅲ.The mechanism may be related with the upregulation of AT2R mRNA and protein expressions by valsartan-eluting stent.

Effect of primary percutaneous transluminal coronary angioplasty and stent implantation on left ventricular remodeling and function in patients with acute myocardial infarction:compared with thrombolytic therapy / 中国介入心脏病学杂志

Objective To observe prospectively the changes of left ventricular size and function, and to evaluate the impact of primary percutaneous transluminal coronary angioplasty (p-PTCA) and stent implantation and thrombolytic therapy on left ventricular remodeling and function. Methods The patients with a first acute myocardial infarct and without contraindications to thrombolytic therapy were randomly assingned to p-PTCA group or urokinase (1?500?000 IU) therapy group within 12 hrs from the onset of symptoms or within 12～24 hrs if the evidence of myocardial ischemia in infarc zones was available. Two-demensional echocardaography were applied in the 2 nd , 12 th , and 24 th week after infarction, and major cardiac events were recorded. Results Sixty-five patients were enrolled (male 55, female 10, age 58.95?8.94 y). The patency of infarct related artery of 32 patients assigned to p-PTCA was 100%, while that of thrombolytic therapy group (33 patients) was 75.76%. The differences of end-systolic volume index (ESVI), end-diastolic volume index (EDVI), left ventricular ejection fraction (LVEF), and regional wall motion score index (RWMI) were significant statistically between p-PTCA group and thrombolytic therapy group ( P