The impact of adolescents' health motivation on the relationship among mental stress, physical exercise, and stress symptoms during COVID-19: A dual moderation model.

Objective: Many Chinese teenagers are experiencing high mental stress levels due to epidemic-related restrictions and closures. Mental stress can induce numerous associated symptoms, and physical exercise is considered to buffer mental stress. However, it remains unclear whether health motivation regulates the relationships among mental stress, physical exercise, and stress symptoms. This study examined whether mental stress events during the epidemic can predict stress symptoms, whether physical exercise can buffer mental stress, and whether the mental stress buffer effect is enhanced when health motivation regarding physical exercise is high. Methods: In total, 2,420 junior high school students (1,190 boys and 1,230 girls; 826 seventh-grade students, 913 eighth-grade students, and 681 ninth-grade students) from nine provinces nationwide were selected to investigate mental stress events, symptoms, health motivation, and physical exercise in adolescents. The hypothesis was tested with a multiple regression analysis. Results: A positive relationship between adolescent mental stress events and stress symptoms was observed, and an interactive relationship was found among health motivation, physical exercise, and mental stress factors. Specifically, the mental stress-buffering effect of physical exercise was significant only when health motivation was high. Conclusion: In the post-epidemic period, the influence of mental stress events on stress symptoms in adolescents was found to be buffered by physical exercise only in terms of high health motivation. This result highlighted the role of health motivation in the buffering effect of physical exercise on mental stress during an epidemic.

Impact of vaccination against COVID-19 on the outcomes of in vitro fertilization-embryo transfer: a retrospective cohort study.

BACKGROUND: Vaccination against coronavirus disease 2019 (COVID-19) has become the primary approach in the fight against the spread of COVID-19. Studies have shown that vaccination against COVID-19 has adverse effects, particularly on human reproductive health, despite the fact that vaccination rates are still on the rise. However, few studies have reported whether vaccination affects the outcome of in vitro fertilization-embryo transfer (IVF-ET) or not. In this study, we compared the outcome of IVF-ET and the development of follicles and embryos between vaccinated and unvaccinated groups. METHODS: A single-center retrospective cohort study of 10,541 in vitro fertilization (IVF) cycles was conducted from June 2020 to August 2021. 835 IVF cycles with a history of vaccination against COVID-19 and 1670 IVF cycles that served as negative controls were selected and analyzed utilizing the Matchlt package of R software ( http://www.R-project.org/ ) and the nearest neighbor matching algorithm for propensity-matched analysis at a 1:2 ratio. RESULTS: The number of oocytes collected in the vaccinated group and the unvaccinated group were 8.00 (0, 40.00) and 9.00 (0, 77.00) ( P  = 0.073) and the good-quality embryo rates of the two groups were 0.56±0.32 and 0.56±0.31 averagely ( P  = 0.964). Clinical pregnancy rates for the vaccinated group and unvaccinated group were 42.4% (155/366) and 40.2% (328/816) ( P  = 0.486) and biochemical pregnancy rates were 7.1% (26/366) and 8.7% (71/816) ( P  = 0.355). Two other factors were analyzed in this study; vaccination among different genders and different types (inactivated vaccine or recombinant adenovirus vaccine) showed no statistically significant effect on the above outcomes. CONCLUSIONS: In our findings, vaccination against COVID-19 showed no statistically significant effect on the outcomes of IVF-ET and the development of follicles and embryos, nor did the gender of the vaccinated person or the formulation of vaccines show significant effects.

Efficacy of blood urea nitrogen-to-albumin ratio for predicting prognostic outcomes of inpatients with COVID-19: A meta-analysis.

BACKGROUND: The associations between blood urea nitrogen (BUN)/albumin ratio and poor prognosis in patients with diagnosis of coronavirus disease 2019 (COVID-19) remain to be clarified. METHODS: A search based on 4 electronic databases (i.e., EMBASE, Google scholar, MEDLINE, and Cochrane Library) was performed on June 23, 2022. The association of BUN/Albumin ratio with poor prognostic outcomes, defined as patients with mortality/severe illnesses, were analyzed. RESULTS: Results from analysis of 7 cohort studies (3600 individuals with COVID-19) published between 2020 and 2022 showed a higher BUN/Albumin ratio in the poor-prognosis group (Mean difference:  = 2.838, 95% confidence interval: 2.015-3.66, P < .001, I2 = 92.5%) than the good-prognosis group. Additional investigation into the connection between BUN/Albumin ratio as a binary variable (i.e., high or low) and the risk of poor outcome also supported an association between a higher BUN/Albumin ratio and a poor prognostic risk (odd ratio = 3.009, 95% confidence interval: 1.565-5.783, P = .001, I2 = 93.7%, 5 studies). Merged analysis of poor prognosis produced a sensitivity of 0.76, specificity of 0.72, and area under curve of 0.81. CONCLUSION: This meta-analysis demonstrated a positive correlation between BUN/albumin ratio and poor outcome in patients with COVID-19. Additional large-scale prospective studies are needed to verify our findings.

Divalent siRNAs are bioavailable in the lung and efficiently block SARS-CoV-2 infection.

The continuous evolution of SARS-CoV-2 variants complicates efforts to combat the ongoing pandemic, underscoring the need for a dynamic platform for the rapid development of pan-viral variant therapeutics. Oligonucleotide therapeutics are enhancing the treatment of numerous diseases with unprecedented potency, duration of effect, and safety. Through the systematic screening of hundreds of oligonucleotide sequences, we identified fully chemically stabilized siRNAs and ASOs that target regions of the SARS-CoV-2 genome conserved in all variants of concern, including delta and omicron. We successively evaluated candidates in cellular reporter assays, followed by viral inhibition in cell culture, with eventual testing of leads for in vivo antiviral activity in the lung. Previous attempts to deliver therapeutic oligonucleotides to the lung have met with only modest success. Here, we report the development of a platform for identifying and generating potent, chemically modified multimeric siRNAs bioavailable in the lung after local intranasal and intratracheal delivery. The optimized divalent siRNAs showed robust antiviral activity in human cells and mouse models of SARS-CoV-2 infection and represent a new paradigm for antiviral therapeutic development for current and future pandemics.

Viral Entry Inhibitors Targeting Six-Helical Bundle Core against Highly Pathogenic Enveloped Viruses with Class I Fusion Proteins.

Type Ⅰ enveloped viruses bind to cell receptors through surface glycoproteins to initiate infection or undergo receptor-mediated endocytosis and initiate membrane fusion in the acidic environment of endocytic compartments, releasing genetic material into the cell. In the process of membrane fusion, envelope protein exposes fusion peptide, followed by an insertion into the cell membrane or endosomal membrane. Further conformational changes ensue in which the type 1 envelope protein forms a typical six-helix bundle structure, shortening the distance between viral and cell membranes so that fusion can occur. Entry inhibitors targeting viral envelope proteins, or host factors, are effective antiviral agents and have been widely studied. Some have been used clinically, such as T20 and Maraviroc for human immunodeficiency virus 1 (HIV-1) or Myrcludex B for hepatitis D virus (HDV). This review focuses on entry inhibitors that target the six-helical bundle core against highly pathogenic enveloped viruses with class I fusion proteins, including retroviruses, coronaviruses, influenza A viruses, paramyxoviruses, and filoviruses.

Immune Repertoire Sequencing Reveals an Abnormal Adaptive Immune System in COVID-19 Survivors.

Accumulating evidence suggests that SARS-CoV-2 impairs the adaptive immune system during acute infection. Still, it remains largely unclear whether the frequency and functions of T and B cells return to normal after the recovery of COVID-19. Here, we analyzed immune repertoires and SARS-CoV-2-specific neutralization antibodies in a prospective cohort of 40 COVID-19 survivors with a six-month follow-up after hospital discharge. Immune repertoire sequencing revealed abnormal T- and B-cell expression and function with large TCR/BCR clones, decreased diversity, abnormal class switch recombination and somatic hypermutation. A decreased number of B cells but an increased proportion of CD19+ CD138+ B cells were found in COVID-19 survivors. The proportion of CD4+ T cells, especially circulating follicular helper T (cTfh) cells, was increased, whereas the frequency of CD3+ CD4- T cells was decreased. SARS-CoV-2-specific neutralization IgG and IgM antibodies were identified in all survivors, especially those recorded with severe COVID-19 who showed a higher inhibition rate of neutralization antibodies. All severe cases complained of more than one COVID-19 sequelae after 6 months of recovery. Overall, our findings indicate that SARS-CoV-2-specific antibodies remain detectable even after 6 months of recovery. Because of their abnormal adaptive immune system with a low number of CD3+ CD4- T cells and high susceptibility to infections, COVID-19 patients might need more time and medical care to fully recover from immune abnormalities and tissue damage. This article is protected by copyright. All rights reserved.

Solvent-Responsive Magnetic Beads for Accurate Detection of SARS-CoV-2.

Although numerous approaches were proposed for the nucleic acid (NA)-based SARS-CoV-2 detection, the nonideal NA desorption efficiency of conventional magnetic beads (MBs) limits their widespread application. In this study, we developed solvent-responsive MBs (called responsive MBs), which, in the presence of buffers, modulated the absorption and desorption capacities of NA by flipping the surface -COO-. Relative to other commercial MBs, responsive MBs exhibited similar absorption profiles and markedly enhanced desorption profiles. When applied for NA detection of complex samples, responsive MBs exhibited better performance of RNA detection than DNA, with obvious advantages in sensitivity. Specifically, the RNA and DNA desorption rates of commercial MBs were ∼85 and 82.5%, while those of responsive MBs were nearly 94 and 93.5%, respectively. Furthermore, responsive MBs exhibited remarkable extraction ability in a wide range of tissues and better performance of RNA extraction than DNA. When applied for SARS-CoV-2 detection, the responsive MBs along with the simulated digital RT-LAMP (a previously established apparatus) further improved detection efficiency, yielding a precise quantitative detection as low as 25 copies and an ultimate sensibility detection of 5 copies/mL. It was also successfully employed in numerous NA-based technologies such as polymerase chain reaction (PCR), sequencing, and so on.

Effects of heterogeneous susceptibility on epidemiological models of reinfection.

This paper studies an epidemic model with heterogeneous susceptibility which generalizes the SIS (susceptible-infected-susceptible), SIR (susceptible-infected-recovered) and SIRI (susceptible-infected-recovered-infected) models. The proposed model considers the case that some infected people are susceptible again after recovery, some infected people develop immunity after infection, and some infected people are reinfected after recovery. We perform a comprehensive theoretical analysis of the model, showing that under appropriate initial conditions, delayed outbreak phenomenon occurs that can give people false impressions. Moreover, compared with the SIRI model, the proposed model exists the delayed outbreak phenomenon under more probable conditions. Finally, we present a numerical example to illustrate the effectiveness of the theoretical results.

Worse psychological traits associated with higher probability of emotional problems during the Omicron pandemic in Tianjin, China.

Background and Objectives: Individuals with specific psychological weaknesses are prone to mental problems during the coronavirus pandemic. This self-rating study assessed the combined effects of infection-related stress, resilience, worry, and loneliness on the likelihood of depression and anxiety among infected and non-infected individuals during the Tianjin Pandemic in 2022. Methods: Individuals infected with Omicron (n = 249) and health residents (n = 415) were recruited from two hospitals and communities in Tianjin. Each respondent completed the following on-site assessment: Self-developed Scale of Demographics, Zung Self-Rating Depression Scale (SDS), Zung Self-Rating Anxiety Scale (SAS), the Connor-Davidson Resilience Scale (CD-RISC), De Jong Gierveld Scale (DJGLS), and the Penn State Worry Questionnaire (PSWQ). The respondents were categorized into depression or non-depression group by SDS scores, and anxiety or non-anxiety group by SAS scores. Results: The overall scores of CD-RISC, DJGJLS, and PSWQ were significantly different both between the depression group and non-depression groups and between the anxiety group and non-anxiety groups. The greater likelihood of depression was associated with lower overall scores of CD-RISC and higher scores of PSWQ; the greater likelihood of anxiety was associated with higher scores of PSWQ. The likelihood of depression was also positively associated with having infection-related stress and three demographics. Conclusions: This on-site study demonstrates the importance of specific traits in a small-scale pandemic: the worse resilience and the greater worry propensity related to the higher probability of depression, and the greater propensity of worry related to the higher probability of anxiety. Moreover, those experiencing infection-related stress, being male, living alone, and being unemployed are more likely to have depressive problems.

Methotrexate inhibition of SARS-CoV-2 entry, infection and inflammation revealed by bioinformatics approach and a hamster model.

Background: Drug repurposing is a fast and effective way to develop drugs for an emerging disease such as COVID-19. The main challenges of effective drug repurposing are the discoveries of the right therapeutic targets and the right drugs for combating the disease. Methods: Here, we present a systematic repurposing approach, combining Homopharma and hierarchal systems biology networks (HiSBiN), to predict 327 therapeutic targets and 21,233 drug-target interactions of 1,592 FDA drugs for COVID-19. Among these multi-target drugs, eight candidates (along with pimozide and valsartan) were tested and methotrexate was identified to affect 14 therapeutic targets suppressing SARS-CoV-2 entry, viral replication, and COVID-19 pathologies. Through the use of in vitro (EC50 = 0.4 µM) and in vivo models, we show that methotrexate is able to inhibit COVID-19 via multiple mechanisms. Results: Our in vitro studies illustrate that methotrexate can suppress SARS-CoV-2 entry and replication by targeting furin and DHFR of the host, respectively. Additionally, methotrexate inhibits all four SARS-CoV-2 variants of concern. In a Syrian hamster model for COVID-19, methotrexate reduced virus replication, inflammation in the infected lungs. By analysis of transcriptomic analysis of collected samples from hamster lung, we uncovered that neutrophil infiltration and the pathways of innate immune response, adaptive immune response and thrombosis are modulated in the treated animals. Conclusions: We demonstrate that this systematic repurposing approach is potentially useful to identify pharmaceutical targets, multi-target drugs and regulated pathways for a complex disease. Our findings indicate that methotrexate is established as a promising drug against SARS-CoV-2 variants and can be used to treat lung damage and inflammation in COVID-19, warranting future evaluation in clinical trials.

Immunoglobulin Y Specific for SARS-CoV-2 Spike Protein Subunits Effectively Neutralizes SARS-CoV-2 Infectivity and Ameliorates Disease Manifestations In Vivo.

(Background) The coronavirus disease 2019 (COVID-19) that is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) carries high infectivity and mortality. Efficient intervention strategies are urgently needed. Avian immunoglobulin Y (IgY) showed efficacy against viral infection whereas the in vivo efficacy remains unclear. (Methods) We immunized laying hens with S1, S1 receptor-binding domain (S1-RBD), or S2 subunits of the SARS-CoV-2 spike (S) protein. After immunization, IgYs were collected and extracted from the egg yolks. The neutralization potential of IgYs was examined by the plaque reduction neutralization test (PRNT). The bioutility of IgYs was examined in Syrian hamsters in vivo. (Results) IgYs exhibited typical banding patterns in SDS-PAGE and Western blot and were immunoreactive against S1, S1-RBD, and S2 subunits. The plaque reduction neutralization test (PRNT) showed that all purified IgYs potently neutralized different SARS-CoV-2 strains in vitro. In Syrian hamsters, the combination of IgYs for S1-RBD and S2 subunits administered before or after SARS-CoV-2 infection effectively restored body weight loss and reduced intrapulmonary lesions and the amount of immunoreactive N protein-positive cells, which were caused by SARS-CoV-2 infection. (Conclusions) Collectively, IgYs specific for S protein subunits effectively neutralized SARS-CoV-2 in vitro and in vivo and may serve as prophylactic or therapeutic antibodies in the prevention or treatment of COVID-19.

Anti-SARS-CoV-2 Activity of Adamantanes In Vitro and in Animal Models of Infection.

Coronavirus disease 2019 (COVID-19) has had devastating effects worldwide, with particularly high morbidity and mortality in outbreaks on residential care facilities. Amantadine, originally licensed as an antiviral agent for therapy and prophylaxis against influenza A virus, has beneficial effects on patients with Parkinson's disease and is used for treatment of Parkinson's disease, multiple sclerosis, acquired brain injury, and various other neurological disorders. Recent observational data suggest an inverse relationship between the use of amantadine and COVID-19. Adamantanes, including amantadine and rimantadine, are reported to have in vitro activity against severe acute respiratory syndrome coronavirus (SARS-CoV) and, more recently, SARS-CoV-2. We hypothesized that adamantanes have antiviral activity against SARS-CoV-2, including variant strains. To assess the activity of adamantanes against SARS-CoV-2, we used in vitro and in vivo models of infection. We established that amantadine, rimantadine, and tromantadine inhibit the growth of SARS-CoV-2 in vitro in cultured human epithelial cells. While neither rimantadine nor amantadine reduces lung viral titers in mice infected with mouse-adapted SARS-CoV-2, rimantadine significantly reduces viral titers in the lungs in golden Syrian hamsters infected with SARS-CoV-2. In summary, rimantadine has antiviral activity against SARS-CoV-2 in human alveolar epithelial cells and in the hamster model of SARS-CoV-2 lung infection. The evaluation of amantadine or rimantadine in human randomized controlled trials can definitively address applications for the treatment or prevention of COVID-19.

Preparation of the RIPK3 Polyclonal Antibody and Its Application in Immunoassays of Nephropathogenic Infectious Bronchitis Virus-Infected Chickens.

Receptor interacting protein kinase 3 (RIPK3) is a vital serine/threonine kinase in regulating the programmed destruction of infected cells to defend against RNA viruses. Although the role of RIPK3 in viruses in mice is well characterized, it remains unclear where in nephropathogenic infectious bronchitis virus (NIBV) in chickens. Here, we use a self-prepared polyclonal antibody to clarify the abundance of RIPK3 in tissues and define the contributions of RIPK3 in tissue damage caused by NIBV infection in chickens. Western blot analyses showed that RIPK3 polyclonal antibody can specifically recognize RIPK3 in the vital tissues of Hy-Line brown chicks and RIPK3 protein is abundantly expressed in the liver and kidney. Moreover, NIBV significantly upregulated the expression levels of RIPK3 in the trachea and kidney of chicks in a time-dependent manner. In addition, the activation of necroptosis in response to NIBV infection was demonstrated by the coimmunoprecipitation (CoIP) experiments through RIPK3 in the necrosome, which phosphorylates its downstream mixed-spectrum kinase structural domain-like protein (MLKL). Our findings offered preliminary insights into the key role of RIPK3 protein in studying the underlying mechanism of organ failure caused by NIBV infection.

Effect on implant drills and postoperative reactions for pre-extraction interradicular implant bed preparation during the COVID-19 pandemic and beyond.

The aim of the present study was to observe the abrasion of implant drills and postoperative reactions for the preparation of the interradicular immediate implant bed during the COVID-19 pandemic and beyond. Thirty-two implant drills were included in four groups: blank, improved surgery, traditional surgery, and control. In the improved surgery group, a dental handpiece with a surgical bur was used to decoronate the first molar and create a hole in the middle of the retained root complex, followed by the pilot drilling protocol through the hole. The remaining root complex was separated using a surgical bur and then extracted. Subsequently, the implant bed was prepared. Implant drills were used in the traditional surgery group to complete the decoronation, hole creation, and implant-drilling processes. The tooth remained intact until the implant bed was prepared. The surface roughness of the pilot drill was observed and measured. Surgery time, postoperative reactions (swelling, pain, and trismus), and fear of coronavirus disease 2019 scale (FCV-19S) were measured and recorded, respectively. Statistical analysis revealed significant difference with surface roughness among blank group (0.41 ± 0.05 µm), improved surgery group (0.37 ± 0.06 µm), traditional surgery group (0.16 ± 0.06 µm), and control group (0.26 ± 0.04 µm) (P < .001). Significant differences were revealed with surgery time between improved surgery group (5.63 ± 1.77 min) and traditional surgery group (33.63 ± 2.13 min) (P < .001). Swelling, pain, and trismus (improved group: r ≥ 0.864, P ≤ .006; traditional group: r ≥ 0.741, P ≤ .035) were positively correlated with the FCV-19S. This study proved that a new pilot drill could only be used once in traditional surgery but could be used regularly in improved surgery. Improved surgery was more effective, efficient, and economical than the traditional surgery. The higher FCV-19S, the more severe swelling, pain, and trismus.

Programmable antivirals targeting critical conserved viral RNA secondary structures from influenza A virus and SARS-CoV-2.

Influenza A virus's (IAV's) frequent genetic changes challenge vaccine strategies and engender resistance to current drugs. We sought to identify conserved and essential RNA secondary structures within IAV's genome that are predicted to have greater constraints on mutation in response to therapeutic targeting. We identified and genetically validated an RNA structure (packaging stem-loop 2 (PSL2)) that mediates in vitro packaging and in vivo disease and is conserved across all known IAV isolates. A PSL2-targeting locked nucleic acid (LNA), administered 3 d after, or 14 d before, a lethal IAV inoculum provided 100% survival in mice, led to the development of strong immunity to rechallenge with a tenfold lethal inoculum, evaded attempts to select for resistance and retained full potency against neuraminidase inhibitor-resistant virus. Use of an analogous approach to target SARS-CoV-2, prophylactic administration of LNAs specific for highly conserved RNA structures in the viral genome, protected hamsters from efficient transmission of the SARS-CoV-2 USA_WA1/2020 variant. These findings highlight the potential applicability of this approach to any virus of interest via a process we term 'programmable antivirals', with implications for antiviral prophylaxis and post-exposure therapy.

Association of Prognostic Nutritional Index with Severity and Mortality of Hospitalized Patients with COVID-19: A Systematic Review and Meta-Analysis.

The associations of prognostic nutritional index (PNI) with disease severity and mortality in patients with coronavirus disease 2019 (COVID-19) remain unclear. Electronic databases, including MEDLINE, EMBASE, Google scholar, and Cochrane Library, were searched from inception to 10 May 2022. The associations of PNI with risk of mortality (primary outcome) and disease severity (secondary outcome) were investigated. Merged results from meta-analysis of 13 retrospective studies (4204 patients) published between 2020 and 2022 revealed a lower PNI among patients in the mortality group [mean difference (MD): -8.65, p < 0.001] or severity group (MD: -5.19, p < 0.001) compared to those in the non-mortality or non-severity groups. A per-point increase in PNI was associated with a reduced risk of mortality [odds ratio (OR) = 0.84, 95% CI: 0.79 to 0.9, p < 0.001, I2 = 67.3%, seven studies] and disease severity (OR = 0.84, 95% CI: 0.77 to 0.92, p < 0.001, I2 = 83%, five studies). The pooled diagnostic analysis of mortality yielded a sensitivity of 0.76, specificity of 0.71, and area under curve (AUC) of 0.79. Regarding the prediction of disease severity, the sensitivity, specificity, and AUC were 0.8, 0.61, and 0.65, respectively. In conclusion, this study demonstrated a negative association between PNI and prognosis of COVID-19. Further large-scale trials are warranted to support our findings.

Effect Evaluation of Echocardiography on Right Ventricular Function in Patients after the Recovering from Coronavirus Disease 2019.

This research was aimed at exploring the changes in right ventricular function in patients after the recovery of coronavirus disease 2019 (COVID-19) under echocardiography and providing a reference for the rehabilitation and treatment of COVID-19 patients. Three echocardiographic follow-up examinations were performed on 40 recovered COVID-19 patients and 40 healthy people. Right ventricular function between patients after COVID-19 rehabilitation and healthy people was compared. The mean values of right ventricular fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), right ventricular ejection fraction (RVEF), right myocardial performance index (RMPI), and tricuspid annular plane systolic speed (S') were compared between patients after COVID-19 rehabilitation and healthy subjects. The technical parameters of two-dimensional speckle tracking were compared. The results showed that the differences in RVFAC, TAPSE, RVEF, and RMPI between COVID-19 patients and healthy controls were not significant during the three follow-up periods (P > 0.05). At the first follow-up, the S' was 12.78 cm/s in COVID-19 patients and 13.18 cm/s in healthy subjects. At the second follow-up, the S' was 11.98 cm/s in COVID-19 patients and 12.77 cm/s in healthy subjects. At the third follow-up, the S' was 12.79 cm/s in COVID-19 patients and 13.12 cm/s in healthy subjects. There was no significant difference between the two groups (P > 0.05). In addition, there was no significant difference in right ventricular function between COVID-19 patients and healthy controls, and there was no significant difference in cardiovascular symptoms (P > 0.05). In summary, COVID-19 had no substantial effect on right ventricular function and better recovery in patients.

Association between Fibrinogen-to-Albumin Ratio and Prognosis of Hospitalized Patients with COVID-19: A Systematic Review and Meta-Analysis.

Although the fibrinogen-to-albumin ratio (F/R ratio) has been used as an inflammation marker to predict clinical outcomes in patients with cardiovascular diseases, its association with the prognosis of patients with coronavirus disease 2019 (COVID-19) remains unclear. Electronic databases including EMBASE, MEDLINE, Google Scholar, and Cochrane Library were searched from inception to 20 June 2022. The associations of F/R ratio with poor prognosis (defined as the occurrence of mortality or severe disease) were investigated in patients with COVID-19. A total of 10 studies (seven from Turkey, two from China, one from Croatia) involving 3675 patients published between 2020 and 2022 were eligible for quantitative syntheses. Merged results revealed a higher F/R ratio in the poor prognosis group (standardized mean difference: 0.529, p < 0.001, I2 = 84.8%, eight studies) than that in the good prognosis group. In addition, a high F/R ratio was associated with an increased risk of poor prognosis (odds ratio: 2.684, I2 = 59.5%, five studies). Pooled analysis showed a sensitivity of 0.75, specificity of 0.66, and area under curve of 0.77 for poor prognosis prediction. In conclusion, this meta-analysis revealed a positive correlation between F/A ratio and poor prognostic outcomes of COVID-19. Because of the limited number of studies included, further investigations are warranted to support our findings.

A Newly Engineered A549 Cell Line Expressing ACE2 and TMPRSS2 Is Highly Permissive to SARS-CoV-2, Including the Delta and Omicron Variants.

New variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to emerge, causing surges, breakthrough infections, and devastating losses-underscoring the importance of identifying SARS-CoV-2 antivirals. A simple, accessible human cell culture model permissive to SARS-CoV-2 variants is critical for identifying and assessing antivirals in a high-throughput manner. Although human alveolar A549 cells are a valuable model for studying respiratory virus infections, they lack two essential host factors for SARS-CoV-2 infection: angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). SARS-CoV-2 uses the ACE2 receptor for viral entry and TMPRSS2 to prime the SARS-CoV-2 spike protein, both of which are negligibly expressed in A549 cells. Here, we report the generation of a suitable human cell line for SARS-CoV-2 studies by transducing human ACE2 and TMPRSS2 into A549 cells. We show that subclones highly expressing ACE2 and TMPRSS2 ("ACE2plus" and the subclone "ACE2plusC3") are susceptible to infection with SARS-CoV-2, including the delta and omicron variants. These subclones express more ACE2 and TMPRSS2 transcripts than existing commercial A549 cells engineered to express ACE2 and TMPRSS2. Additionally, the antiviral drugs EIDD-1931, remdesivir, nirmatrelvir, and nelfinavir strongly inhibit SARS-CoV-2 variants in our infection model. Our data show that ACE2plusC3 cells are highly permissive to SARS-CoV-2 infection and can be used to identify anti-SARS-CoV-2 drugs.

SARS-CoV-2 ORF8 reshapes the ER through forming mixed disulfides with ER oxidoreductases.

The replication machinery of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is closely associated with the endoplasmic reticulum (ER) in host cells. Activation of the unfolded protein response (UPR) is a strategy hijacked by coronavirus to facilitate its replication and suppress host innate immunity. Here, we have found that SARS-CoV-2 ORF8 protein accumulates in the ER and escapes the degradation system by forming mixed disulfide complexes with ER oxidoreductases. ORF8 induces the activation of three UPR pathways through targeting key UPR components, remodels ER morphology and accelerates protein trafficking. Moreover, small molecule reducing agents release ORF8 from the mixed disulfide complexes and facilitate its degradation, therefore mitigate ER stress. Our study reveals a unique mechanism by which SARS-CoV-2 ORF8 escapes degradation by host cells and regulates ER reshaping. Targeting ORF8-involved mixed disulfide complexes could be a new strategy to alleviate SARS-CoV-2 induced ER stress and related diseases.