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Dengue, caused by the dengue virus (DENV), is a global health threat transmitted by Aedes mosquitoes, resulting in 400 million cases annually. The disease ranges from mild to severe, with potential progression to hemorrhagic dengue. Current research is focused on natural antivirals due to challenges in vector control. This study evaluates the antiviral potential of peptides derived from the microalgae Phaeodactylum tricornutum, known for its bioactive compounds. Microalgae were cultivated under controlled conditions, followed by protein extraction and hydrolysis to produce four peptide fractions. These fractions were assessed for cytotoxicity via the MTT assay and antiviral activity against DENV serotype 2 using flow cytometry and plaque formation assays. The 10–30 kDa peptide fraction, at 150 and 300 μg/mL concentrations, demonstrated no cytotoxicity and significantly reduced the percentage of infected cells and viral titers. These findings suggest that peptides derived from Phaeodactylum tricornutum exhibit promising antiviral activity against dengue virus serotype 2, potentially contributing to developing new therapeutic approaches for dengue. [ABSTRACT FROM AUTHOR]

COVID-19 has a mortality rate exceeding 5.4 million worldwide. The early identification of patients at a high risk of mortality is essential to save their lives. The AST-to-lymphocyte ratio index (ALRI) is a novel biomarker of survival in patients with hepatocellular carcinoma, an organ susceptible to SARS-CoV-2 infection. For this study, the prognostic value of ALRI as a marker of COVID-19 mortality was evaluated. For this purpose, ALRI was compared with the main biomarkers for COVID-19 mortality (neutrophil-to-lymphocyte ratio [NLR], systemic immune-inflammation index [SII], platelet-to-lymphocyte ratio [PLR], lactate dehydrogenase (LDH)/lymphocyte ratio [LDH/LR]). A retrospective cohort of 225 patients with SARS-CoV-2 infection and without chronic liver disease was evaluated. In the non-survival group, the ALRI, NLR, SII, and LDH/LR were significantly higher than in the survival group (pcorrected < 0.05). ALRI had an area under the curve (AUC) of 0.81, a sensitivity of 70.37%, and a specificity of 75%, with a best cut-off value >42.42. COVID-19 patients with high ALRI levels had a mean survival time of 7.8 days. Multivariate Cox regression revealed that ALRI > 42.42 (HR = 2.32, 95% CI: 1.35–3.97; pcorrected = 0.01) was a prognostic factor of COVID-19 mortality. These findings prove that ALRI is an independent predictor of COVID-19 mortality and that it may help identify high-risk subjects with SARS-CoV-2 infection upon admission. [ABSTRACT FROM AUTHOR]

The tetraspanin CD81 has been reported to play an essential role as viral receptor, in the fusion of endosomal and viral membranes, genome replication, the release of viral particles, and the formation of extracellular vesicles with infectious components. However, the role of CD81 during dengue virus infection is little known. In this study, we analyzed the participation of CD81 in the infection of dengue virus serotype 2 incubating antibodies anti-CD81 in Huh-7 cells before interaction with exosomes or viral particles. Our results showed a significant reduction in the expression levels of viral proteins and the percentage of infected cells compared to infected cells without antibodies. These results suggest that CD81 is involved in the initial steps of dengue virus replicative cycle. [ABSTRACT FROM AUTHOR]

The Dengue (DENV) and Zika (ZIKV) viruses have been increasing in the last decade in the Americas. For lack of vaccines, FDA-approved drugs have been proposed in recent years to combat these viruses, most notably lipid-lowering drugs, which have demonstrated a wide in vitro antiviral spectrum. However, despite being safe, in vivo assays remain critical to reduce the risk of adverse effects during their use as antivirals. Therefore, the present study focuses on the advantages and disadvantages of using AG129 transgenic mice, triple knock-out for interferon alpha (INF-α), beta (INF-β) and gamma receptor (INFr-γ), as an in vivo model for the evaluation of candidate lipid-lowering drugs for treatment against flaviviruses. Immunodeficient AG129 mice showed the advantage of exhibiting clinical signs of ZIKV and DENV disease. However, we observed differences between females and males, during infection and lipid-lowering drug treatments, that should be considered. MET increased survival time and decreased disease severity of DENV-infected mice. Interestingly, MET did not counteract ZIKV disease in vivo; on the contrary, exacerbated severe signs were observed in females that require further study. [ABSTRACT FROM AUTHOR]

COVID-19 has a mortality toll exceeding 5.4 million worldwide. Early identification of patients at high mortality risk is essential to save their lives. AST-to-lymphocyte ratio index (ALRI) is a novel biomarker of survival in patients with hepatocellular carcinoma, an organ susceptible to SARS-CoV-2 infection. The prognostic value of ALRI as a marker of COVID-19 mortality was evaluated. For this purpose, ALRI was compared with main biomarkers for COVID-19 mortality (neutrophil-to-lymphocyte ratio [NLR], systemic immune-inflammation index [SII], plate-let-to-lymphocyte ratio [PLR], lactate dehydrogenase (LDH)/lymphocyte ratio [LDH/LR]). A retrospective cohort of 225 patients with SARS-CoV-2 infection and without chronic liver disease was evaluated. In non-survival group, the ALRI, NLR, SII, and LDH/LR were significantly higher than in survival group (Pcorrected < 0.05). ALRI had an area under the curve (AUC) of 0.81, sensitivity 70.37 %, and specificity 75 %, with a best cut-off value > 42.42. COVID-19 patients with high ALRI levels had a mean survival time of 7.8 days. Multivariate Cox regression revealed that ALRI > 42.42 (HR = 2.32, 95 % CI: 1.35-3.97; Pcorrected = 0.01) was a prognostic factor of COVID-19 mortality. These findings prove that ALRI is an independent predictor of COVID-19 mortality and may help identify high-risk subjects with SARS-CoV-2 infection at admission. [ABSTRACT FROM AUTHOR]