Harringtonine: A more effective antagonist for Omicron variant.

Fusion with host cell membrane is the main mechanism of infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we propose that a new strategy to screen small-molecule antagonists blocking SARS-CoV-2 membrane fusion. Using cell membrane chromatography (CMC), we found that harringtonine (HT) simultaneously targeted SARS-CoV-2 S protein and host cell surface TMPRSS2 expressed by the host cell, and subsequently confirmed that HT can inhibit membrane fusion. HT effectively blocked SARS-CoV-2 original strain entry with the IC50 of 0.217 µM, while the IC50 in delta variant decreased to 0.101 µM, the IC50 in Omicron BA.1 variant was 0.042 µM. Due to high transmissibility and immune escape, Omicron subvariant BA.5 has become the dominant strain of the SARS-CoV-2 virus and led to escalating COVID-19 cases, however, against BA.5, HT showed a surprising effectiveness. The IC50 in Omicron BA.5 was even lower than 0.0019 µM. The above results revealed the effect of HT on Omicron is very significant. In summary, we characterize HT as a small-molecule antagonist by direct targeting on the Spike protein and TMPRSS2.

Unanswered questions on the airborne transmission of COVID-19.

Policies and measures to control pandemics are often failing. While biological factors controlling transmission are usually well explored, little is known about the environmental drivers of transmission and infection. For instance, respiratory droplets and aerosol particles are crucial vectors for the airborne transmission of the severe acute respiratory syndrome coronavirus 2, the causation agent of the coronavirus 2019 pandemic (COVID-19). Once expectorated, respiratory droplets interact with atmospheric particulates that influence the viability and transmission of the novel coronavirus, yet there is little knowledge on this process or its consequences on virus transmission and infection. Here we review the effects of atmospheric particulate properties, vortex zones, and air pollution on virus survivability and transmission. We found that particle size, chemical constituents, electrostatic charges, and the moisture content of airborne particles can have notable effects on virus transmission, with higher survival generally associated with larger particles, yet some viruses are better preserved on small particles. Some chemical constituents and surface-adsorbed chemical species may damage peptide bonds in viral proteins and impair virus stability. Electrostatic charges and water content of atmospheric particulates may affect the adherence of virion particles and possibly their viability. In addition, vortex zones and human thermal plumes are major environmental factors altering the aerodynamics of buoyant particles in air, which can strongly influence the transport of airborne particles and the transmission of associated viruses. Insights into these factors may provide explanations for the widely observed positive correlations between COVID-19 infection and mortality with air pollution, of which particulate matter is a common constituent that may have a central role in the airborne transmission of the novel coronavirus. Supplementary Information: The online version contains supplementary material available at 10.1007/s10311-022-01557-z.

Spike protein mediated membrane fusion during SARS-CoV-2 infection.

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed a serious threat to public health and has quickly become a global concern. The infection of SARS-CoV-2 begins with the binding of its spike protein to the receptor-angiotensin-converting enzyme 2 (ACE2), which, after a series of conformation changes, results in the fusion of viral-cell membranes and the release of the viral RNA genome into the cytoplasm. In addition, infected host cells can express spike protein on their cell surface, which will interact with ACE2 on neighboring cells, leading to cell membrane fusion and the formation of multinucleated cells or syncytia. Both viral entry and syncytia formation are mediated by spike-ACE2 interaction and share some common mechanisms of membrane fusion. Here in this review, we will summarize our current understanding of spike-mediated membrane fusion, which may shed light on future broad-spectrum antiviral development.

Unanswered questions on the airborne transmission of COVID-19

Policies and measures to control pandemics are often failing. While biological factors controlling transmission are usually well explored, little is known about the environmental drivers of transmission and infection. For instance, respiratory droplets and aerosol particles are crucial vectors for the airborne transmission of the severe acute respiratory syndrome coronavirus 2, the causation agent of the coronavirus 2019 pandemic (COVID-19). Once expectorated, respiratory droplets interact with atmospheric particulates that influence the viability and transmission of the novel coronavirus, yet there is little knowledge on this process or its consequences on virus transmission and infection. Here we review the effects of atmospheric particulate properties, vortex zones, and air pollution on virus survivability and transmission. We found that particle size, chemical constituents, electrostatic charges, and the moisture content of airborne particles can have notable effects on virus transmission, with higher survival generally associated with larger particles, yet some viruses are better preserved on small particles. Some chemical constituents and surface-adsorbed chemical species may damage peptide bonds in viral proteins and impair virus stability. Electrostatic charges and water content of atmospheric particulates may affect the adherence of virion particles and possibly their viability. In addition, vortex zones and human thermal plumes are major environmental factors altering the aerodynamics of buoyant particles in air, which can strongly influence the transport of airborne particles and the transmission of associated viruses. Insights into these factors may provide explanations for the widely observed positive correlations between COVID-19 infection and mortality with air pollution, of which particulate matter is a common constituent that may have a central role in the airborne transmission of the novel coronavirus. Supplementary Information The online version contains supplementary material available at 10.1007/s10311-022-01557-z.

Rapid quantitative monitoring of SARS-CoV-2 spike protein-mediated syncytia formation using split NanoLuc.

SARS-CoV-2 infection causes syncytial pneumocyte in patients and this has been considered as a defining feature of severe COVID-19 cases. Traditional methods of syncytia quantification require the morphology characterization of fused cells either with light microscope or fluorescent microscope, which is time-consuming and not accurate. Here we developed a rapid and sensitive coculture system measuring spike-induced syncytia by using NanoLuc complementation system. We found the formation of syncytia occurred rapidly after ACE2-expressing cells exposure to spike protein. In addition, we found furin cleavage as well as the cell surface protease TMPRSS2 enhanced syncytia formation. Finally, we showed that this coculture system can be used to test the ability of different compound to inhibit syncytia formation, thus providing a useful tool to screen anti-syncytial drugs.

Cytoplasmic domain and enzymatic activity of ACE2 are not required for PI4KB dependent endocytosis entry of SARS-CoV-2 into host cells.

The recent COVID-19 pandemic poses a global health emergency. Cellular entry of the causative agent SARS-CoV-2 is mediated by its spike protein interacting with cellular receptor-human angiotensin converting enzyme 2 (ACE2). Here, by using lentivirus based pseudotypes bearing spike protein, we demonstrated that entry of SARS-CoV-2 into host cells was dependent on clathrin-mediated endocytosis, and phosphoinositides played essential roles during this process. In addition, we showed that the intracellular domain and the catalytic activity of ACE2 were not required for efficient virus entry. Finally, we showed that the current predominant Delta variant, although with high infectivity and high syncytium formation, also entered cells through clathrin-mediated endocytosis. These results provide new insights into SARS-CoV-2 cellular entry and present proof of principle that targeting viral entry could be an effective way to treat different variant infections.

Identifying Spatial Matching between the Supply and Demand of Medical Resource and Accessing Carrying Capacity: A Case Study of Shenzhen, China.

Previous Studies, such as the evaluation of the supply of and demand for regional medical resources and carrying capacity assessments, require further development. This paper aims to evaluate the carrying capacity and spatial distribution of medical resources in Shenzhen from the perspective of supply and demand, and to conduct a time-series variation of the coupling coordination degree from 1986 to 2019. The two-step floating catchment area method was employed to quantify the carrying capacity and coupling coordination degree method and spatial autocorrelation analysis were applied to analyze spatial distribution between supply and demand. The results were as follows. (1) The carrying capacity index in more than 50% of the districts was classified as low-grade. The percentage of regions with good grades was 8.27%. The regions with a high carrying capacity were distributed in the central and southeastern areas. (2) The coupling coordination continued to rise, increasing from 0.03397 in 1986 to 0.33627 in 2019. (3) The level of supply and demand for medical resources in Shenzhen increased from 1986 to 2019, and the highest degree of compatibility between the supply and the population size was largely concentrated in the western and eastern regions. This research can provide a theoretical reference for Shenzhen to rationally plan medical resources and improve the carrying capacity of medical resources.

Comparison of severe and critical COVID-19 patients imported from Russia with and without influenza A infection in Heilongjiang Province: a retrospective study.

BACKGROUND: The rapid spread of coronavirus disease-19 (COVID-19) poses a global health emergency, and cases entering China from Russia are quite diverse. This study explored and compared the clinical characteristics and outcomes of severe and critically ill COVID-19 patients from Russia with and without influenza A infection, treated in a northern Chinese hospital (Russia imported patients). METHODS: A total of 32 severe and critically ill Russia-imported COVID-19 patients treated in the Heilongjiang Imported Severe and Critical COVID-19 Treatment Center from April 6 to May 11, 2020 were included, including 8 cases (group A) with and 24 cases (group B) without influenza A infection. The clinical characteristics of each group were compared, including prolonged hospital stay, duration of oxygen therapy, time from onset to a negative SARS-CoV-2 qRT-PCR RNA (Tneg) result, and duration of bacterial infection. RESULTS: The results showed that blood group, PaO2/FiO2, prothrombin time (PT), prothrombin activity (PTA), computed tomography (CT) score, hospital stay, duration of oxygenation therapy, Tneg, and duration of bacterial infection were statistically different between the two groups (P<0.05). Multivariant regression analysis showed that the Sequential Organ Failure Assessment (SOFA) score, C-reactive protein (CRP), and influenza A infection were factors influencing hospital stay; SOFA score, CRP, and CT score were factors influencing the duration of oxygenation therapy; PaO2/FiO2, platelet count (PLT), and CRP were factors influencing Tneg; and gender, SOFA score, and influenza A infection were factors influencing the duration of bacterial infection. CONCLUSIONS: Influenza A infection is common in Russia-imported COVID-19 patients, which can prolong the hospital stay and duration of bacterial infection. Routinely screening and treating influenza A should be conducted early in such patients.

Rapid and quantitative detection of SARS-CoV-2 IgG antibody in serum using optofluidic point-of-care testing fluorescence biosensor.

The COVID-19 pandemic brings unprecedented crisis for public health and economics in the world. Detecting specific antibodies to SARS-CoV-2 is a powerful supplement for the diagnosis of COVID-19 and is important for epidemiological studies and vaccine validations. Herein, a rapid and quantitative detection method of anti-SARS-CoV-2 IgG antibody was built based on the optofluidic point-of-care testing fluorescence biosensor. Without complicated steps needed, the portable system is suitable for on-site sensitive determination of anti-SARS-CoV-2 IgG antibody in serum. Under the optimal conditions, the whole detection procedure is about 25 min with a detection limit of 12.5 ng/mL that can well meet the diagnostic requirements. The method was not obviously affected by IgM and serum matrix and demonstrated to have good stability and reliability in real sample analysis. Compared to ELISA test results, the proposed method exhibits several advantages including wider measurement range and easier operation. The method provides a universal platform for rapid and quantitative analysis of other related biomarkers, which is of significance for the prevention and control of COVID-19 pandemic.

Analysis of Risk Factors for Thromboembolic Events in 88 Patients with COVID-19 Pneumonia in Wuhan, China: A Retrospective Descriptive Report.

BACKGROUND Since the outbreak of COVID-19 in December 2019, there have been 96 623 laboratory-confirmed cases and 4784 deaths by December 29 in China. We aimed to analyze the risk factors and the incidence of thrombosis from patients with confirmed COVID-19 pneumonia. MATERIAL AND METHODS Eighty-eight inpatients with confirmed COVID-19 pneumonia were reported (31 critical cases, 33 severe cases, and 24 common cases). The thrombosis risk factor assessment, laboratory results, ultrasonographic findings, and prognoses of these patients were analyzed, and compared among groups with different severity. RESULTS Nineteen of the 88 cases developed DVT (12 critical cases, 7 severe cases, and no common cases). In addition, among the 18 patients who died, 5 were diagnosed with DVT. Positive correlations were observed between the increase in D-dimer level (≥5 µg/mL) and the severity of COVID-19 pneumonia (r=0.679, P<0.01), and between the high Padua score (≥4) and the severity (r=0.799, P<0.01). In addition, the CRP and LDH levels on admission had positive correlations with the severity of illness (CRP: r=0.522, P<0.01; LDH: r=0.600, P<0.01). A negative correlation was observed between the lymphocyte count on admission and the severity of illness (r=-0.523, P<0.01). There was also a negative correlation between the lymphocyte count on admission and mortality in critical patients (r=-0.499, P<0.01). Univariable logistic regression analysis showed that the occurrence of DVT was positively correlated with disease severity (crude odds ratio: 3.643, 95% CI: 1.218-10.896, P<0.05). CONCLUSIONS Our report illustrates that critically or severely ill patients have an associated high D-dimer value and high Padua score, and illustrates that a low threshold to screen for DVT may help improve detection of thromboembolism in these groups of patients, especially in asymptomatic patients. Our results suggest that early administration of prophylactic anticoagulant would benefit the prognosis of critical patients with COVID-19 pneumonia and would likely reduce thromboembolic rates.

Acute right ventricular dysfunction in severe COVID-19 pneumonia.

To investigate the right heart function in coronavirus disease 2019 (COVID-19) patients with acute respiratory distress syndrome (ARDS), a retrospective analysis of 49 COVID-19 patients with ARDS was performed. Patients were divided into severe group and critically-severe group according to the severity of illness. Age-matched healthy volunteers were recruited as a control group. The cardiac cavity diameters, tricuspid annular plane systolic excursion (TAPSE), tricuspid valve regurgitation pressure gradient biggest (TRPG), pulmonary arterial systolic pressure (PASP), maximum inferior vena cava diameter (IVCmax) and minimum diameter (IVCmin), and inferior vena cava collapse index (ICV-CI) were measured using echocardiography. We found that the TAPSE was significantly decreased in pneumonia patients compared to healthy subjects (P < 0.0001), and it was significantly lower in critically-severe patients (P = 0.0068). The TAPSE was less than 17 mm in three (8.6%) severe and five (35.7%) critically-severe patients. In addition, the TAPSE was significantly decreased in severe ARDS patients than in mild ARDS patients. The IVCmax and IVCmin were significantly increased in critically-severe patients compared to healthy subjects and severe patients (P < 0.01), whereas the ICV-CI was significantly decreased (P < 0.05). COVID-19 patients had significantly larger right atrium and ventricle than healthy controls (P < 0.01). The left ventricular ejection fraction (LVEF) in critically-severe patients was significantly lower than that in severe patients and healthy controls (P < 0.05). Right ventricular function was impaired in critically-severe COVID-19 patients. The assessment and protection of the right heart function in COVID-19 patients should be strengthened.

The value of lymphocyte count in determining the severity of COVID-19 and estimating the time for nucleic acid test results to turn negative.

Peripheral blood lymphocyte count is shown to be decreased in patients with COVID-19 in the early stage of the disease. The degree of lymphocyte count reduction is related to COVID-19 severity and could be used as an indicator to reflect the disease severity. Our aim was to investigate the value of lymphocyte count in determining COVID-19 severity and estimating the time for SARS-CoV-2 nucleic acid test results to turn negative. We retrospectively analyzed clinical data of 201 patients with severe and critical COVID-19. The patients were admitted to the West Campus of Union Hospital of Tongji Medical College of Huazhong University of Science and Technology. The data included age, gender, chronic disease, lymphocyte count, and SARS-CoV-2 nucleic acid test results. The age of patients in critically ill group was higher than in severely ill group (p = 0.019). The lymphocyte count of critically ill patients was lower than of severely ill patients. The cutoff value of lymphocyte count to distinguish between the critically ill and the severely ill was 0.735 × 109/L (p = 0.001). The cutoff value of lymphocyte count for SARS-CoV-2 nucleic acid test results turning negative in severely and critically ill patients with chronic diseases (hypertension, diabetes, and coronary heart disease) was 0.835 × 109/L (p = 0.017). The cutoff value of lymphocyte count for SARS-CoV-2 nucleic acid test results turning negative in severely and critically ill male patients was 0.835 × 109/L (p < 0.0001). Lymphocyte count could be an effective indicator to predict COVID-19 severity. It may also be useful in determining the time for nucleic acid test results to turn negative in COVID-19 patients with underlying chronic diseases or male COVID-19 patients with severe and critical conditions.

Clinical characteristics of patients with COVID-19 presenting with gastrointestinal symptoms as initial symptoms: Retrospective case series.

BACKGROUND: A large number of pneumonia cases due to coronavirus disease 2019 (COVID-19) have been first reported in China. Meanwhile, the virus is sweeping all around the world and has infected millions of people. Fever and pulmonary symptoms have been noticed as major and early signs of infection, whereas gastrointestinal symptoms were also observed in a significant portion of patients. The clinical investigation of disease onset was underestimated, especially due to the neglection of cases presenting with gastrointestinal symptoms. AIM: To characterize the clinical features of coronavirus-infected patients with gastrointestinal symptoms as initial symptoms. METHODS: This is a retrospective, single-center case series of the general consecutive hospitalized patients with confirmed COVID-19 at Wuhan Union Hospital from February 2, 2020 to February 13, 2020. According to their initial symptoms, these patients were classified into two groups. Patients in group one presented with pulmonary symptoms (PS) as initial symptoms, and group two presented with gastrointestinal symptoms (GS). Epidemiological, demographic, clinical, laboratory, and treatment data were collected for analysis. RESULTS: Among the 50 patients recruited, no patient has been admitted to intensive care units, and no patient died during the study. The duration of hospitalization was longer in the GS group than in the PS group (12.13 ± 2.44 vs 10.00 ± 2.13, P < 0.01). All of the 50 patients exhibited decreased lymphocytes. However, lymphocytes in the GS group were significantly lower compared to those in the PS group (0.94 ± 0.06 vs 1.04 ± 0.15, P < 0.01). Procalcitonin and hs-CRP were both significantly higher in the GS group than in the PS group. Accordingly, the duration of viral shedding was significantly longer in the GS group compared to the PS group (10.22 ± 1.93 vs 8.15 ± 1.87, P < 0.01). CONCLUSION: COVID-19 patients presenting with gastrointestinal symptoms as initial symptoms need more days of viral shedding and hospitalization than the patients presenting with pulmonary symptoms.

Expert recommendations on blood purification treatment protocol for patients with severe COVID-19.

Coronavirus disease (COVID-19) was first diagnosed in Wuhan in December 2019. The World Health Organization defined the subsequent outbreak of COVID-19 worldwide as a public health emergency of international concern. Epidemiological data indicate that at least 20% of COVID-19 patients have severe disease. In addition to impairment of the respiratory system, acute kidney injury (AKI) is a major complication. Immune damage mediated by cytokine storms and concomitant AKI is a key factor for poor prognosis. Based on previous experience of blood purification for patients with severe acute respiratory syndrome and Middle East respiratory syndrome combined with clinical front-line practice, we developed a blood purification protocol for patients with severe COVID-19. This protocol is divided into four major steps. The first step is to assess whether patients with severe COVID-19 require blood purification. The second step is to prescribe a blood purification treatment for patients with COVID-19. The third step is to monitor and adjust parameters of blood purification. The fourth step is to evaluate the timing of discontinuation of blood purification. It is expected that blood purification will play a key role in effectively reducing the mortality of patients with severe COVID-19 through the standardized implementation of the present protocol.