Immune response in COVID-19: what is next?

Comparative Analysis of Virology and Pathogenesis of SARS-CoV-2 and HIV Infections: Implications for Public Health and Treatment Strategies

Introduction

Coronavirus Disease 19 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and Human Immunodeficiency Virus (HIV) are significant 21st-century pandemics with distinct virological and clinical characteristics. COVID-19 primarily presents as an acute respiratory illness, while HIV leads to chronic immune suppression. Understanding their differences can enhance public health strategies and treatment approaches.

Purpose

This narrative review compares the virology, transmission, immune responses, and clinical outcomes of SARS-CoV-2 and HIV to inform treatment strategies and public health interventions.

Methods

A narrative review was conducted, synthesizing data from peer-reviewed literature and expert commentary from 2010 to 2024. Databases such as PubMed, Cochrane Library, and Google Scholar were searched for relevant studies.

Results

SARS-CoV-2 primarily spreads through airborne droplets and contaminated surfaces, while HIV transmits through direct contact with infected bodily fluids. The immune response to SARS-CoV-2 involves both innate and adaptive systems, potentially leading to a cytokine storm in severe cases. In contrast, HIV evades the immune system by integrating into host cells, resulting in chronic infection and progressive immune deterioration. Treatment for SARS-CoV-2 focuses on symptom management and prevention, with antiviral medications and vaccines playing crucial roles. Conversely, HIV treatment relies on antiretroviral therapy (ART) to suppress viral replication and maintain immune function.

Conclusion

The review highlights the acute nature of SARS-CoV-2 versus the chronic progression of HIV. Tailored prevention and treatment strategies are essential for effective disease management.

Recommendations

Public health strategies should address the unique transmission routes and progression of both viruses. Further research into vaccine development and therapeutic interventions is critical for improving disease management.

Disease progression associated cytokines in COVID-19 patients with deteriorating and recovering health conditions

Understanding the immune response to COVID-19 is challenging due to its high variability among individuals. To identify differentially expressed cytokines between the deteriorating and recovering phases, we analyzed the Electronic Health Records (EHR) and cytokine profile data in a COVID-19 cohort of 444 infected patients and 145 non-infected healthy individuals. We categorized each patient's progression into Deterioration Phase (DP) and Recovery Phase (RP) using longitudinal neutrophil, lymphocyte and lactate dehydrogenase levels. A random forest model was built using healthy and severe patients to compute the contribution of each cytokine toward disease progression using Shapley Additive Explanations (SHAP). SHAP values were used for supervised clustering to identify DP and RP-related samples and their associated cytokines. The identified clusters effectively discriminated DP and RP samples, suggesting that the cytokine profiles differed between deteriorating and recovering health conditions. Especially, CXCL10, GDF15, PTX3, and TNFSF10 were differentially expressed between the DP and RP samples, which are involved in the JAK-STAT, NF- κ B, and MAPK signaling pathways contributing to the inflammatory response. Collectively, we characterized the immune response in terms of disease progression of COVID-19 with deteriorating and recovering health conditions.

Characterization of the symmetrical benzimidazole twin drug TL1228: the role as viral entry inhibitor for fighting COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is reliably one of the largest pandemics the world has suffered in recent years. In the search for non-biological antivirals, special emphasis was placed on drug repurposing to accelerate the clinical implementation of effective drugs.The life cycle of the virus has been extensively investigated and many human targets have been identified, such as the molecular chaperone GRP78, representing a host auxiliary factor for SARS-CoV-2 entry. Here we report the inhibitor capacity of TL1228, a small molecule discovered through an in silico screening approach, which could interfere with the interaction of SARS-CoV-2 and its target cells, blocking the recognition of the GRP78 cellular receptor by the viral Spike protein. TL1228 showed in vitro the ability to reduce significantly both pseudoviral and authentic viral activity even through the reduction of GRP78/ACE2 transcript levels. Importantly, TL1228 acts in modulating expression levels of innate immunity and as inflammation markers.

Immune Profile in COVID-19: Unveiling TR3-56 Cells in SARS-CoV-2 Infection

The emergence of COronaVIrus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), presented a global health challenge since its identification in December 2019. With clinical manifestations ranging from mild respiratory symptoms to severe multi-organ dysfunction, COVID-19 continues to affect populations worldwide. The complex interactions between SARS-CoV-2 variants and the human immune system are crucial for developing effective therapies, vaccines, and preventive measures. Understanding these immune responses highlights the intricate nature of COVID-19 pathogenesis. This retrospective study analyzed, by flow cytometry approach, a cohort of patients infected with SARS-CoV-2 during the initial pandemic waves from 2020 to 2021. It focused on untreated individuals at the time of hospital admission and examined the presence of TR3-56 cells in their immune profiles during the anti-viral immune response. Our findings provide additional insights into the complex immunological dynamics of SARS-CoV-2 infection and highlight the potential role of TR3-56 cells as crucial components of the immune response. We suggest that TR3-56 cells could serve as valuable biomarkers for identifying more severe cases of COVID-19, aiding in the assessment and management of the disease.

Immunological insights: assessing immune parameters in medical professionals exposed to SARS-CoV-2

BACKGROUND

The immunological background responsible for the severe course of COVID-19 and the immune factors that protect against SARS-CoV-2 infection are still unclear. The aim of this study was to investigate immune system status in persons with high exposure to SARS-CoV-2 infection.

METHODS

Seventy-one persons employed in the observation and infectious diseases unit were qualified for the study between November 2020 and October 2021. Symptomatic COVID-19 was diagnosed in 35 persons. Anti-SARS-CoV-2 antibodies were also found in 8 persons. Peripheral blood mononuclear cells subpopulations were analyzed by flow cytometry, and the concentrations of cytokines and anti-SARS-CoV-2 antibodies were determined by ELISA.

RESULTS

The percentages of cytotoxic T lymphocytes (CTLs), CD28+ and T helper (Th) cells with invariant T-cell receptors were significantly higher in persons with symptomatic COVID-19 than in those who did not develop COVID-19' symptoms. Conversely, symptomatic COVID-19 persons had significantly lower percentages of: a) CTLs in the late stage of activation (CD8+/CD95+), b) NK cells, c) regulatory-like Th cells (CD4+/CTLA-4+), and d) Th17-like cells (CD4+/CD161+) compared to asymptomatic COVID-19' persons. Additionally, persons with anti-SARS-CoV-2 antibodies had a significantly higher lymphocyte count and IL-6 concentration than persons without these antibodies.

CONCLUSION

Numerous lymphocyte populations are permanently altered by SARS-CoV-2 infection. High percentages of both populations: NK cells-as a part of the non-specific response, and T helper cells' as those regulating the immune response, could protect against the acute COVID-19 symptoms development. Understanding the immune background of COVID-19 may improve the prevention of this disease by identifying people at risk of a severe course of infection.

TRIAL REGISTRATION

This is a retrospective observational study without a trial registration number.

Changes in Circulating Adipokine Levels in COVID-19 Patients

Objective: The COVID-19 pandemic has posed significant global health challenges. Despite extensive research efforts, the inflammatory response triggered by SARS-CoV-2 remains to be further explored and understood. Our study aims to examine the changes in serum concentrations of pro-inflammatory adipokines-visfatin and leptin-in COVID-19 patients in relation to a healthy control group. Patients/Materials/Subjects and Methods: The study consisted of forty COVID-19 patients and twenty-four healthy patients in the control group. Two serum samples were collected: upon admission and on the seventh day of hospitalization. Concentrations of visfatin and leptin in the serum, alongside routine biochemical parameters, were measured using enzyme immunoassay or enzyme-linked immunosorbent assay kits. The Shapiro-Wilk test was used to assess normality. Differences between independent groups were compared using the Mann-Whitney U test and Kruskal-Wallis ANOVA. Correlations were evaluated with Spearman's rank correlation coefficient. Results: Our findings revealed significantly lower visfatin levels in COVID-19 patients compared to the control group upon admission (4.29 ng/mL, (3.0-6.88 ng/mL) vs. 37.16 ng/mL (24.74-50.12 ng/mL), p < 0.001 for visfatin 1 and 52.05 ng/mL, (31.2-69.66 ng/mL) vs. 37.16 ng/mL (24.74-50.12 ng/mL), p = 0.048 for visfatin 2). The visfatin level of COVID-19 patients returned to the normal levels, established in the control group. However, there was no significant difference in leptin levels between the two groups (p = 0.270 for leptin 1 and p = 0.129 for leptin 2). There was a positive correlation between BMI and leptin concentration (r = 0.66 and p = 0.00). Moreover, it was discovered that COVID-19 independently reduces visfatin levels during the first day of illness. Conclusions: The results of our research suggest that the onset of COVID-19 infection is correlated to visfatin levels. Association with leptin levels remains inconclusive. Further research is imperative to elucidate the intricate role of visfatin and leptin in SARS-CoV-2 infection and their potential as biomarkers for COVID-19 severity and prognosis.

Characteristics of SARS-CoV-2 and Opisthorchis viverrini coinfections: insights into immune responses and clinical outcomes

The effects of co-infections with SARS-CoV-2 and parasitic diseases have been little investigated in terms of immune response, disease dynamics, and clinical outcomes. This study aimed to explore the impact of co-infection with Opisthorchis viverrini and SARS-CoV-2 on the immune response concerning clinical symptoms and the severity of pulmonary abnormalities. A cross-sectional study was conducted, including healthy participants as controls, participants with opisthorchiasis, SARS-CoV-2 infection, and a co-infection group with both diseases. Characteristics of SARS-CoV-2 infection were assessed based on clinical parameters and severity of pulmonary abnormalities, whereas opisthorchiasis burden was evaluated by eggs-per-gram (EPG) counts. Immune responses were assessed by measuring levels of interferon-γ (IFN-γ), SARS-CoV-2 anti-spike receptor binding domain (RBD) IgG, and neutralizing antibody against SARS-CoV-2. In the co-infected group, clinical parameters and hospitalization rates were lower than in the SARS-CoV-2 group. Pulmonary abnormalities, such as bronchial fibrosis, were commonly observed in the SARS-CoV-2 group, leading to hospitalization in some cases. Participants with opisthorchiasis had higher IFN-γ levels than healthy individuals. IFN-γ levels were significantly lower in the co-infection group compared with the SARS-CoV-2 group (P = 0.002). There was a significant (P = 0.044) positive correlation between RBD-specific IgG and percent neutralization levels in the SARS-CoV-2 group. Levels of both were somewhat lower (not statistically significant) in the co-infection group. A negative correlation was observed between opisthorchiasis burden (EPG counts) and IFN-γ and RBD-specific IgG levels in the co-infected group. Following vaccination, the increase in IgG levels against the RBD protein was significantly lower in the co-infected group than in the SARS-CoV-2 group. These results suggest that O. viverrini infection suppresses immune responses and may lead to a reduction in severity in cases of SARS-CoV-2 co-infection.

Comparison of long-term anti-RBD SARS-CoV-2 antibody response following different vaccination schemes in Tunisia

AIM

The study aimed to compare long-term vaccine-induced humoral immunity following different vaccines regimens.

METHODS

Anti-S-RBD total antibody levels were measured in blood samples of 167 participants nearly 6 months post-vaccination. Participants had received one; two or four doses of Pfizer vaccine or who received a third dose of mRNA vaccine (Pfizer) and primed with mRNA (Pfizer/Moderna), adenoviral (AstraZeneca/Jonson & Jonson) or inactivated (CoronaVac/Sinopharm) vaccine.

RESULTS

Among all vaccination regimens, fourth dose of Pfizer achieved the highest S-RBD antibody titers. Nevertheless, the third dose of mRNA vaccine primed with adenoviral vaccine achieved the lowest titers of S-RBD antibody. Notably, the group that received a third dose of mRNA primed with two doses of mRNA vaccine exhibited higher S-RBD antibody compared to groups inoculated with a third dose of mRNA and primed with inactivated or adenovirus vaccine.

CONCLUSION

Our data showed the superiority of three mRNA vaccinations compared to third heterologous vaccine (inactivated of adenoviral) including mRNA as booster in terms of humoral immunogenicity. Our findings supporting the use of additional booster shot from a more potent vaccine type such as mRNA vaccines. Nevertheless, due to the limited number of subjects, it is difficult to extrapolate the results of our study to the whole of Tunisian population. Future studies should investigate a larger cohort and other potential correlates of protection, such as cellular immunity and how it is affected by different vaccination schemes after long-term post-vaccination.

Novel immunomodulatory properties of adenosine analogs promote their antiviral activity against SARS-CoV-2

The COVID-19 pandemic reminded us of the urgent need for new antivirals to control emerging infectious diseases and potential future pandemics. Immunotherapy has revolutionized oncology and could complement the use of antivirals, but its application to infectious diseases remains largely unexplored. Nucleoside analogs are a class of agents widely used as antiviral and anti-neoplastic drugs. Their antiviral activity is generally based on interference with viral nucleic acid replication or transcription. Based on our previous work and computer modeling, we hypothesize that antiviral adenosine analogs, like remdesivir, have previously unrecognized immunomodulatory properties which contribute to their therapeutic activity. In the case of remdesivir, we here show that these properties are due to its metabolite, GS-441524, acting as an Adenosine A2A Receptor antagonist. Our findings support a new rationale for the design of next-generation antiviral agents with dual - immunomodulatory and intrinsic - antiviral properties. These compounds could represent game-changing therapies to control emerging viral diseases and future pandemics.

Anti-virus activity and mechanisms of natural polysaccharides from medicinal herbs

There has been a sudden increase in viral diseases, such as coronavirus disease 2019 (COVID-19), causing significant harm to human and animal well-being, as well as economic development. Medicinal herbs, with a history of thousands of years in clinical use, contain versatile polysaccharides as one of their primary compounds. This review offers an overview of the antiviral effects of polysaccharides from medicinal herbs on viruses in humans, poultry, swine and aquaculture in recent years. The mechanism of these antiviral polysaccharides, involved in hindering various stages of the viral life cycle thereby blocking virus infection, is summarized. The review also explores other underlying mechanisms of antiviral effects, such as enhancing the immune response, regulating inflammatory reactions, balancing gut flora, reducing oxidative stress, and suppressing apoptosis through various corresponding signaling pathways. The structure-function relationships discussed in this article also aid in understanding the antiviral mechanism of natural polysaccharides, indicating the need for more in-depth research and analysis. Natural polysaccharides from medicinal herbs have emerged as valuable resources in the fight against viral infections, exhibiting high effectiveness. This review emphasizes the promising role of polysaccharides from medicinal herbs as potential candidates for blocking viral infections in humans and animals.

Neutrophil extracellular traps characterize caseating granulomas

Tuberculosis (TB) remains one of the top 10 causes of death worldwide and still poses a serious challenge to public health. Recent attention to neutrophils has uncovered unexplored areas demanding further investigation. Therefore, the aim of this study was to determine neutrophil activation and circulatory neutrophil extracellular trap (NET) formation in various types of TB. Sera from TB patients (n = 91) and healthy controls (NHD; n = 38) were analyzed for NE-DNA and MPO-DNA complexes, cell-free DNA (cfDNA), and protease activity (elastase). We show that these NET parameters were increased in TB sera. Importantly, NET formation and NE activity were elevated in TB patients with extensive tissue damage when compared to those with minor damage and in patients with relapse, compared to new cases. We discuss the importance of balancing NET formation to prevent tissue damage or even relapse and argue to analyze circulating NET parameters to monitor the risk of disease relapse. To investigate the tissues for NETs and to find the source of the circulating NET degradation products, we collected sections of granulomas in lung and lymph node biopsies. Samples from other diseases with granulomas, including sarcoidosis (SARC) and apical periodontitis (AP), served as controls. Whereas NET formation characterizes the caseating granulomas, both caseating and non-caseating granulomas harbor DNA with unusual conformation. As TB is associated with hypercoagulation and thromboembolism, we further imaged the pulmonary vessels of TB patients and detected vascular occlusions with neutrophil aggregates. This highlights the dual role of neutrophils in the pathology of TB.

Chemokine receptors in COVID-19 infection

Chemokine receptors play diverse roles in the immune response against pathogens by recruiting innate and adaptive immune cells to sites of infection. However, their involvement could also be detrimental, causing tissue damage and exacerbating respiratory diseases by triggering histological alterations such as fibrosis and remodeling. This chapter reviews the role of chemokine receptors in the immune defense against SARS-CoV-2 infection. In COVID-19, CXCR3 is expressed mainly in T cells, and its upregulation is related to an increase in SARS-CoV-2-specific antibodies but also to COVID-19 severity. CCR5 is a key player in T-cell recruitment, and its suppression leads to reduced inflammation and viremia levels. Conversely, CXCR6 is implicated in the aberrant migration of memory T cells within airways. On the other hand, increased CCR4+ cells in the blood and decreased CCR4+ cells in lung cells are associated with severe COVID-19. Additionally, CCR2 is associated with an increase in macrophage recruitment to lung tissues. Elevated levels of CXCR1 and CXCR2, which are predominantly expressed in neutrophils, are associated with the severity of the disease, and finally, the expression of CX3CR1 in cytotoxic T lymphocytes affects the retention of these cells in lung tissues, thereby impacting the severity of COVID-19. Despite the efforts of many clinical trials to find effective therapies for COVID-19 using chemokine receptor inhibitors, no conclusive results have been found due to the small number of patients, redundancy, and co-expression of chemokine receptors by immune cells, which explains the difficulty in finding a single therapeutic target or effective treatment.

A critical review of Ginger's (Zingiber officinale) antioxidant, anti-inflammatory, and immunomodulatory activities

Ginger (Zingiber officinale) is a rhizome that has been used as a healthy herbal plant for years. Ginger's chemical components are recognized to provide beneficial health effects, namely as antioxidants and anti-inflammatory agents with the potential to operate as immunomodulators. This literature review covers numerous publications concerning ginger's immunomodulatory potential, associated with antioxidant and anti-inflammatory effects in modifying the body's immune system. Pathophysiology of oxidative stress and inflammation were introduced before diving deep down into the herbal plants as an immunomodulator. Ginger's antioxidant and anti-inflammatory properties are provided by gingerol, shogaols, paradol, and zingerone. Ginger's antioxidant mechanism is linked to Nrf2 signaling pathway activation. Its anti-inflammatory mechanism is linked to Akt inhibition and NF-KB activation, triggering the release of anti-inflammatory cytokines while reducing proinflammatory cytokines. Ginger consumption as food and drink was also explored. Overall, ginger and its active components have been shown to have strong antioxidant properties and the potential to reduce inflammation. Challenges and future prospects of ginger are also elaborated for future development. Future collaborations between researchers from various fields, including chemists, biologists, clinicians, pharmacists, and the food industry, are required further to investigate the effect of ginger on human immunity. Collaboration between researchers and industry can help accelerate the advancement of ginger applications.

Role of Inflammation in the Development of COVID-19 to Parkinson's Disease

Background

The coronavirus disease 2019 (COVID-19) can lead to neurological symptoms such as headaches, confusion, seizures, hearing loss, and loss of smell. The link between COVID-19 and Parkinson's disease (PD) is being investigated, but more research is needed for a definitive connection.

Methods

Datasets GSE22491 and GSE164805 were selected to screen differentially expressed gene (DEG), and immune infiltration and gene set enrichment analysis (GSEA) of the DEG were performed. WGCNA analyzed the DEG and selected the intersection genes. Potential biological functions and signaling pathways were determined, and diagnostic genes were further screened using gene expression and receiver operating characteristic (ROC) curves. Screening and molecular docking of ibuprofen as a therapeutic target. The effectiveness of ibuprofen was verified by constructing a PD model in vitro, and constructing "COVID19-PD" signaling pathway, and exploring the role of angiotensin-converting enzyme 2 (ACE2) in PD.

Results

A total of 13 DEG were screened from the GSE36980 and GSE5281 datasets. Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that the DEG were mainly associated with the hypoxia-inducible factor (HIF-1), epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor resistance, etc. After analysis, it is found that ibuprofen alleviates PD symptoms by inhibiting the expression of nuclear factor kappa-B (NF-κB), interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α). Based on signal pathway construction, the importance of ACE2 in COVID-19-induced PD has been identified. ACE2 is found to have widespread distribution in the brain. In the 1-methyl-4-phenyl-1,2,3,6-te-trahydropyridine (MPTP)-induced ACE2-null PD mice model, more severe motor and non-motor symptoms, increased NF-κB p65 and α-synuclein (α-syn) expression with significant aggregation, decreased tyrosine hydroxylase (TH), severe neuronal loss, and neurodegenerative disorders.

Conclusion

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection increases the risk of PD through an inflammatory environment and downregulation of ACE2, providing evidence for the molecular mechanism and targeted therapy associated with COVID-19 and PD.

Current landscape of long COVID clinical trials

Long COVID was reported as a multi-systemic condition after the infection of SARS-CoV-2, and more than 65 million people are suffering from this disease. It has been noted that around 10% of severe SARS-CoV-2 infected individuals are suffering from the enduring effects of long COVID. The symptoms of long COVID have also been noted in several mild or asymptomatic SARS-CoV-2 infected individuals. While limited reports on clinical trials investigating new therapeutics for long COVID exist, there is an abundance of scattered information available regarding these trials. This review explores the extensive literature search, and complete clinical trial database search to map the current status of long COVID clinical trials worldwide. The study listed about 110 long COVID clinical trials. In addition to conducting extensive long COVID clinical trials, we have comprehensively presented an overview of the condition, its symptoms, notable manifestations, associated clinical trials, the unique challenges it poses, and our recommendations for addressing long COVID.

A Comprehensive Review on Navigating the Neurological Landscape of COVID-19: Insights Into Etiopathogenesis and Clinical Management

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as a global health crisis with significant neurological implications. While initially characterized by respiratory symptoms, COVID-19 has been increasingly recognized for its diverse neurological manifestations, including encephalopathy, stroke, peripheral neuropathies, and neuropsychiatric disorders. Understanding the neurological landscape of COVID-19 is essential for elucidating its pathophysiology, optimizing clinical management, and improving patient outcomes. This comprehensive review provides insights into the etiopathogenesis, clinical manifestations, diagnostic approaches, management strategies, and prognostic implications of neurological involvement in COVID-19. Mechanistic insights highlight the multifactorial nature of neurological complications involving direct viral invasion, immune-mediated mechanisms, and thrombotic events. Diagnostic challenges underscore the importance of a multidisciplinary approach to patient care, while management strategies emphasize early recognition and appropriate intervention. Long-term neurological sequelae and prognostic factors are also examined, emphasizing the need for comprehensive follow-up and rehabilitation services. Finally, recommendations for future research prioritize efforts to elucidate underlying mechanisms, identify biomarkers, and evaluate rehabilitative interventions. By addressing these challenges, we can better understand and mitigate the neurological consequences of the ongoing COVID-19 pandemic.

The gasdermin family: emerging therapeutic targets in diseases

The gasdermin (GSDM) family has garnered significant attention for its pivotal role in immunity and disease as a key player in pyroptosis. This recently characterized class of pore-forming effector proteins is pivotal in orchestrating processes such as membrane permeabilization, pyroptosis, and the follow-up inflammatory response, which are crucial self-defense mechanisms against irritants and infections. GSDMs have been implicated in a range of diseases including, but not limited to, sepsis, viral infections, and cancer, either through involvement in pyroptosis or independently of this process. The regulation of GSDM-mediated pyroptosis is gaining recognition as a promising therapeutic strategy for the treatment of various diseases. Current strategies for inhibiting GSDMD primarily involve binding to GSDMD, blocking GSDMD cleavage or inhibiting GSDMD-N-terminal (NT) oligomerization, albeit with some off-target effects. In this review, we delve into the cutting-edge understanding of the interplay between GSDMs and pyroptosis, elucidate the activation mechanisms of GSDMs, explore their associations with a range of diseases, and discuss recent advancements and potential strategies for developing GSDMD inhibitors.

Transcriptional-profile changes in the medial geniculate body after noise-induced tinnitus

Tinnitus is a disturbing condition defined as the occurrence of acoustic hallucinations with no actual sound. Although the mechanisms underlying tinnitus have been explored extensively, the pathophysiology of the disease is not completely understood. Moreover, genes and potential treatment targets related to auditory hallucinations remain unknown. In this study, we examined transcriptional-profile changes in the medial geniculate body after noise-induced tinnitus in rats by performing RNA sequencing and validated differentially expressed genes via quantitative polymerase chain reaction analysis. The rat model of tinnitus was established by analyzing startle behavior based on gap-pre-pulse inhibition of acoustic startles. We identified 87 differently expressed genes, of which 40 were upregulated and 47 were downregulated. Pathway-enrichment analysis revealed that the differentially enriched genes in the tinnitus group were associated with pathway terms, such as coronavirus disease COVID-19, neuroactive ligand-receptor interaction. Protein-protein-interaction networks were established, and two hub genes (Rpl7a and AC136661.1) were identified among the selected genes. Further studies focusing on targeting and modulating these genes are required for developing potential treatments for noise-induced tinnitus in patients.

Comparison of Computed Tomography and Clinical Features Between Patients Infected with the SARS-CoV-2 Omicron Variant and the Original Strain

Purpose

To investigate potential differences in clinical and computed tomography (CT) features between patients with the SARS-CoV-2 Omicron variant and the original strain.

Patients and Methods

This retrospective study included 69 hospitalized patients infected with Omicron variant from November to December 2022, and 96 hospitalized patients infected with the original strain from February to March 2020 in Chongqing, China. The clinical features, CT manifestations, degrees of lung involvement in different stages on CT, and imaging changes after the reverse-transcription polymerase chain reaction (RT-PCR) results turned negative were compared between the two groups.

Results

For clinical features, patients with Omicron were predominantly old people and females, without manifestation of any clinical symptoms, who had low serum levels of C-reactive protein and procalcitonin. Shorter interval from symptoms onset to initial CT scan was observed in Omicron patients compared to patients with the original strain (all P < 0.05). For CT features, patients with Omicron were more likely to present with round-like opacities and tree-in-bud pattern (all P < 0.05), but less likely to exhibit a diffuse distribution, patchy and linear opacities, as well as vascular enlargement pattern (all P < 0.05). The Omicron group was more susceptible to exhibiting lower CT involvement scores in each stage (all P < 0.05) and imaging progression after the RT-PCR results turned negative (P < 0.001).

Conclusion

Patients infected with the Omicron variant exhibited less severe changes on chest CT compared to those infected with the original strain. Furthermore, imaging progression under low viral load conditions was more common in patients with Omicron than in those with the original strain.

Studying the correlation of inflammatory cytokines to COVID-19 disease

Extreme response of the immune system develops cytokine storm which might be crucial in the pathology of COVID-19. The research aims to evaluate the serum level of IL-6, TNF-α, and IP-10 in severe, mild, and pre-vaccinated one-dose COVID-19 patients and investigate their clinical value and effect in the disease development among different groups of patients. A total of 72 samples were collected 18 as healthy control and 54 from confirmed COVID-19 patients including 18 mild, 18 severe, and 18 pre-vaccinated (one dose). It was confirmed that the severe group of COVID-19 patients had the highest circulating IL-6, TNF- α, and IP-10. IL-6 level in mild and pre-vaccinated (one dose) was significantly lower than in severe. In conclusion, IL-6, TNF-α, and IP-10 are associated with the pathogenicity of COVID-19, furthermore, vaccination could help to control severity of the disease.

Immune response variation in mild and severe COVID-19 patients

Sixty patients with COVID-19 infection were categorized into mild and severe groups, and their immune response was analyzed using flow cytometry and complete blood count. An observed increase in immune activation parameters, notably a higher percentage of CD4 lymphocytes co-expressing CD69 and CD25 molecules, and enhanced activity of the macrophage-monocyte cell line was noted in the mild group. Although Group 2 (severe COVID) had fewer CD4 cells, significant migration and proliferation were evident, with increased CD4CD69, CD8 HLA-DR+, and CD8CD69 lymphocytes. The CD4 to CD8 ratio in Group 1 suggested potential autoimmune reactions, while Group 2 indicated potential immunosuppression from severe infection and employing immunosuppressive drugs. Additionally, Group 2 exhibited an increased neutrophil count, hinting at possible bacterial co-infection. Group 1 showed differences in CD4RO and CD8RA lymphocyte populations, implying that cellular immunity plays a role in developing efficient postinfectious immunity. This intimation suggests that vaccination might mitigate the severity of the coronavirus infection and prevent complications, including long-term COVID-19.

The most exposed regions of SARS-CoV-2 structural proteins are subject to strong positive selection and gene overlap may locally modify this behavior

The SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic that emerged in 2019 has been an unprecedented event in international science, as it has been possible to sequence millions of genomes, tracking their evolution very closely. This has enabled various types of secondary analyses of these genomes, including the measurement of their sequence selection pressure. In this work, we have been able to measure the selective pressure of all the described SARS-CoV-2 genes, even analyzed by sequence regions, and we show how this type of analysis allows us to separate the genes between those subject to positive selection (usually those that code for surface proteins or those exposed to the host immune system) and those subject to negative selection because they require greater conservation of their structure and function. We have also seen that when another gene with an overlapping reading frame appears within a gene sequence, the overlapping sequence between the two genes evolves under a stronger purifying selection than the average of the non-overlapping regions of the main gene. We propose this type of analysis as a useful tool for locating and analyzing all the genes of a viral genome when an adequate number of sequences are available.IMPORTANCEWe have analyzed the selection pressure of all severe acute respiratory syndrome coronavirus 2 genes by means of the nonsynonymous (Ka) to synonymous (Ks) substitution rate. We found that protein-coding genes are exposed to strong positive selection, especially in the regions of interaction with other molecules (host receptor and genome of the virus itself). However, overlapping coding regions are more protected and show negative selection. This suggests that this measure could be used to study viral gene function as well as overlapping genes.

Longitudinal single cell atlas identifies complex temporal relationship between type I interferon response and COVID-19 severity

Due to the paucity of longitudinal molecular studies of COVID-19, particularly those covering the early stages of infection (Days 1-8 symptom onset), our understanding of host response over the disease course is limited. We perform longitudinal single cell RNA-seq on 286 blood samples from 108 age- and sex-matched COVID-19 patients, including 73 with early samples. We examine discrete cell subtypes and continuous cell states longitudinally, and we identify upregulation of type I IFN-stimulated genes (ISGs) as the predominant early signature of subsequent worsening of symptoms, which we validate in an independent cohort and corroborate by plasma markers. However, ISG expression is dynamic in progressors, spiking early and then rapidly receding to the level of severity-matched non-progressors. In contrast, cross-sectional analysis shows that ISG expression is deficient and IFN suppressors such as SOCS3 are upregulated in severe and critical COVID-19. We validate the latter in four independent cohorts, and SOCS3 inhibition reduces SARS-CoV-2 replication in vitro. In summary, we identify complexity in type I IFN response to COVID-19, as well as a potential avenue for host-directed therapy.

ERS International Congress 2023: highlights from the Paediatrics Assembly

Respiratory health in children is essential for general wellbeing and healthy development in the short and long term. It is well known that many respiratory diseases in adulthood have their origins in early life, and therefore research on prevention of respiratory diseases and management of children with respiratory diseases will benefit patients during the full life course. Scientific and clinical advances in the field of respiratory health are moving at a fast pace. This article summarises some of the highlights in paediatric respiratory medicine presented at the hybrid European Respiratory Society (ERS) International Congress 2023 which took place in Milan (Italy). Selected sessions are summarised by Early Career Members of the Paediatrics Assembly (Assembly 7) under the supervision of senior ERS officers, and cover a wide range of research areas in children, including respiratory physiology and sleep, asthma and allergy, cystic fibrosis, respiratory infection and immunology, neonatology and intensive care, respiratory epidemiology and bronchology.

Perspectives on Post-COVID-19 Pulmonary Fibrosis Treatment

Pulmonary fibrosis, a critical outcome of chronic inflammatory diseases, has gained prominence in the context of post-coronavirus (post-COVID-19) complications. This review delves into the multifaceted landscape of post-COVID-19 pulmonary fibrosis, elucidating the intricate molecular mechanisms underlying its pathogenesis and highlighting promising therapeutic avenues. Examining the aftermath of severe acute respiratory syndrome-2 (SARS-CoV-2) infection, the review reveals key signaling pathways implicated in the fibrotic cascade. Drawing parallels with previous coronavirus outbreaks enhances our understanding of the distinctive features of post-COVID-19 fibrosis. Antifibrotic drugs, like pirfenidone and nintedanib, take center stage; their mechanisms of action and potential applications in post-COVID-19 cases are thoroughly explored. Beyond the established treatments, this review investigates emerging therapeutic modalities, including anti-interleukin agents, immunosuppressants, and experimental compounds, like buloxybutide, saracatinib, sirolimus, and resveratrol. Emphasizing the critical importance of early intervention, this review highlights the dynamic nature of post-COVID-19 pulmonary fibrosis research. In conclusion, the synthesis of current knowledge offers a foundation for advancing our approaches to the prevention and treatment of these consequential sequelae of COVID-19.

Immune targets to stop future SARS-CoV-2 variants

IMPORTANCE

The emergence of SARS-CoV-2 had a major impact across the world. It is true that the collaboration of scientists from all over the world resulted in a rapid response against COVID-19, mainly with the development of vaccines against the disease. However, many viral genetic variants that threaten vaccines have emerged. Our study reveals highly conserved antigenic regions in the vaccines have emerged. Our study reveals highly conserved antigenic regions in the spike protein in all variants of concern (Alpha, Beta, Gamma, Delta, and Omicron) as well as in the wild-type virus. Such immune targets can be used to fight future SARS-CoV-2 variants.

Alleviating hypoxia to improve cancer immunotherapy

Tumor hypoxia resulting from abnormal and dysfunctional tumor vascular network poses a substantial obstacle to immunotherapy. In fact, hypoxia creates an immunosuppressive tumor microenvironment (TME) through promoting angiogenesis, metabolic reprogramming, extracellular matrix remodeling, epithelial-mesenchymal transition (EMT), p53 inactivation, and immune evasion. Vascular normalization, a strategy aimed at restoring the structure and function of tumor blood vessels, has been shown to improve oxygen delivery and reverse hypoxia-induced signaling pathways, thus alleviates hypoxia and potentiates cancer immunotherapy. In this review, we discuss the mechanisms of tumor tissue hypoxia and its impacts on immune cells and cancer immunotherapy, as well as the approaches to induce tumor vascular normalization. We also summarize the evidence supporting the use of vascular normalization in combination with cancer immunotherapy, and highlight the challenges and future directions of this overlooked important field. By targeting the fundamental problem of tumor hypoxia, vascular normalization proposes a promising strategy to enhance the efficacy of cancer immunotherapy and improve clinical outcomes for cancer patients.

Incidence and risk factors related to SARS-CoV-2 infection, reinfection, and seroconversion: Analysis of a healthcare workers cohort from a university hospital in Colombia

Objectives

To determine the incidence and factors associated with SARS-CoV-2 infection and seroconversion among healthcare workers (HCWs) during the COVID-19 pandemic in a university hospital in Colombia.

Methods

We analyzed the CoVIDA-Fundación Santa Fe de Bogotá (FSFB) cohort, consisting of 419 HCWs from the FSFB university hospital. The cohort was followed during active surveillance (June 25, 2020, to April 30, 2021) and passive surveillance (May 01, 2021, to March 16, 2022) periods. Incidence rates for SARS-CoV-2 infection, reinfection, and seroconversion were estimated, considering pre- and post-COVID-19 vaccination. Cox proportional-hazards models were used to identify factors related to infection and seroconversion during the active surveillance period.

Results

COVID-19 incidence rate ranged between 16-52 cases per 1000 person-month. SARS-CoV-2 reinfections were rare, ranging between less than one case to 13 cases per 1000 person-month. The seroconversion rates ranged between 52-55 cases per 1000 person-month. High socioeconomic level was a protective factor for SARS-CoV-2 infection, while SARS-CoV-2 infection was the main factor associated with seroconversion.

Conclusion

This study provides insights into the incidence and risk factors of SARS-CoV-2 infection among HCWs in a Colombian university hospital. The findings may offer valuable guidance for reducing virus spread within healthcare settings.

The Effects of Fermented Feed on the Growth Performance, Antioxidant Activity, Immune Function, Intestinal Digestive Enzyme Activity, Morphology, and Microflora of Yellow-Feather Chickens

This experiment was conducted to investigate the effects of fermented feed on growth performance, antioxidant activity, immune function, intestinal digestive enzyme activity, morphology, and microflora of yellow-feather chickens. A total of 240 one-day-old female yellow-feathered (Hexi dwarf) chickens were randomly divided into two treatment groups, with six replicates per group and 20 chickens per replicate. The control group (CK) received a basal diet, whereas the experimental group was fed a basal diet of +2.00% fermented feed (FJ). The trial lasted for 22 days. Compared with the CK, (1) the growth performance was not affected (p > 0.05); (2) immunoglobin a, immunoglobin g, immunoglobin m, interleukin-1β, and interleukin-6 were affected (p < 0.05); (3) liver superoxide dismutase, glutathione peroxidase, and catalase were higher (p < 0.05); (4) trypsin activity in the duodenum and cecal Shannon index were increased (p < 0.05); (5) the relative abundance of Actinobacteriota in cecum was increased (p < 0.05); (6) the abundance of dominant microflora of Bacteroides as well as Clostridia UCG-014_norank were increased (p < 0.05). In summary, the fermented feed improved the growth performance, antioxidant activity, immune function, intestinal digestive enzyme activity, morphology, and microflora of yellow-feather chickens.

Curcumin as an antiviral agent and immune-inflammatory modulator in COVID-19: A scientometric analysis

Background

Reports regarding the antiviral activity of curcumin have surfaced. However, to date there has been no scientometric analysis of the relationship between curcumin and Coronavirus Disease 2019 (COVID-19). To comprehensively understand the studies involving curcumin in the context of COVID-19, we conducted a scientometric analysis to provide an exhaustive review of these studies.

Methods

We systematically searched the Web of Science core collection database for bibliographic data indexed from January 1, 2020, to December 31, 2022, using keywords such as 'curcumin', 'COVID-19', and their synonyms. To clarify the research content and trends related to curcumin in COVID-19, we utilized VOSviewer, Origin 2023, and Charticulator for analysis, supplemented by external data.

Results

The final count of publications included in this study was 252. These publications originated from 63 countries or territories, with India contributing the highest number of publications. They were published across 170 journals. Notably, the Egyptian Knowledge Bank (EKB) emerged as the most important institution that carried out this study. The most cited publication had been referenced 166 times. The main elements involved in the keyword analysis were reflected in the antiviral activity of curcumin and the immuno-inflammatory modulation of the inflammatory cytokine storm. Furthermore, the pharmacological mechanisms of curcumin for treating COVID-19 emerged as a prominent area of research. Simultaneously, there exists direct evidence of clinical usage of curcumin to enhance COVID-19 outcomes.

Conclusions

The scientometric analysis underscores the burgeoning professional domain of curcumin-based treatment for COVID-19. Ongoing studies have focused on the antiviral activity of curcumin and its immunomodulatory effects on inflammatory cytokine storms. On the other hand, the pharmacological mechanism of curcumin in the treatment of COVID-19 is a hot spot in the research field at present, which may become the main research trend in this field in the future. While maintaining a focus on foundational research, the clinical application of curcumin in COVID-19 infection is developing in parallel, highlighting its obvious guiding value in clinical practice. These insights offer researchers a snapshot of the present state of curcumin treatment for COVID-19 and guide further mechanistic validation efforts in the future.

Macrophage polarization and metabolism in atherosclerosis

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of fatty deposits in the inner walls of vessels. These plaques restrict blood flow and lead to complications such as heart attack or stroke. The development of atherosclerosis is influenced by a variety of factors, including age, genetics, lifestyle, and underlying health conditions such as high blood pressure or diabetes. Atherosclerotic plaques in stable form are characterized by slow growth, which leads to luminal stenosis, with low embolic potential or in unstable form, which contributes to high risk for thrombotic and embolic complications with rapid clinical onset. In this complex scenario of atherosclerosis, macrophages participate in the whole process, including the initiation, growth and eventually rupture and wound healing stages of artery plaque formation. Macrophages in plaques exhibit high heterogeneity and plasticity, which affect the evolving plaque microenvironment, e.g., leading to excessive lipid accumulation, cytokine hyperactivation, hypoxia, apoptosis and necroptosis. The metabolic and functional transitions of plaque macrophages in response to plaque microenvironmental factors not only influence ongoing and imminent inflammatory responses within the lesions but also directly dictate atherosclerotic progression or regression. In this review, we discuss the origin of macrophages within plaques, their phenotypic diversity, metabolic shifts, and fate and the roles they play in the dynamic progression of atherosclerosis. It also describes how macrophages interact with other plaque cells, particularly T cells. Ultimately, targeting pathways involved in macrophage polarization may lead to innovative and promising approaches for precision medicine. Further insights into the landscape and biological features of macrophages within atherosclerotic plaques may offer valuable information for optimizing future clinical treatment for atherosclerosis by targeting macrophages.

Neutralizing antibody and T-cell responses against SARS-CoV-2 variants by heterologous CoronaVac/ChAdOx-1 vaccination in elderly subjects with chronic obstructive pulmonary disease

BACKGROUND

Data on humoral and cellular immune responses against SARS-CoV-2 after receiving heterologous CoronaVac/ChAdOx-1 (CoVac/ChAd) vaccination in subjects with chronic obstructive pulmonary disease (COPD) are still limited. Therefore, we determined the neutralizing antibody (NAb) and T-cell responses against SARS-CoV-2 wild type (WT) and variants of concern (VOCs) in COPD patients.

METHODS

The levels of NAb as well as specific CD4 and CD8 T-cell responses against SARS-CoV-2 WT and VOCs were determined in COPD patients before and after vaccination.

RESULTS

Four weeks after vaccinations, the median levels of % inhibition of NAb against SARS-CoV-2 WT, Alpha, Beta, and Delta variants were significantly higher compared to pre-vaccination. The induction of NAb against Omicron was very low compared to other variants. At four weeks after vaccination, in comparison to pre-vaccination, the increasing trend of TNF-α-, IFN-γ-, IL-4-, IL-17-, IL-10-, and FasL-producing CD4 T-cells upon stimulation with WT spike peptides were demonstrated. No difference in T-cell responses to spike peptides of Alpha, Beta, and Delta variants and their WT homologs was observed.

CONCLUSION

Heterologous CoVac/ChAd vaccine induced the production of NAb against SARS-CoV-2 WT, Alpha, Beta, and Delta variants, but low for Omicron in COPD patients. Induction of CD4 T-cell subset responses was slightly observed by this vaccine regimen.

CLINICAL TRIALS REGISTRY

This study was approved by the Clinical Trials Registry (Study ID: TCTR20210822002).

Harnessing metabolism of hepatic macrophages to aid liver regeneration

Liver regeneration is a dynamic and regulated process that involves inflammation, granulation, and tissue remodeling. Hepatic macrophages, abundantly distributed in the liver, are essential components that actively participate in each step to orchestrate liver regeneration. In the homeostatic liver, resident macrophages (Kupffer cells) acquire a tolerogenic phenotype and contribute to immunological tolerance. Following toxicity-induced damage or physical resection, Kupffer cells as well as monocyte-derived macrophages can be activated and promote an inflammatory process that supports the survival and activation of hepatic myofibroblasts and thus promotes scar tissue formation. Subsequently, these macrophages, in turn, exhibit the anti-inflammatory effects critical to extracellular matrix remodeling during the resolution stage. However, continuous damage-induced chronic inflammation generally leads to hepatic macrophage dysfunction, which exacerbates hepatocellular injury and triggers further liver fibrosis and even cirrhosis. Emerging macrophage-targeting strategies have shown efficacy in both preclinical and clinical studies. Increasing evidence indicates that metabolic rewiring provides substrates for epigenetic modification, which endows monocytes/macrophages with prolonged "innate immune memory". Therefore, it is reasonable to conceive novel therapeutic strategies for metabolically reprogramming macrophages and thus mediate a homeostatic or reparative process for hepatic inflammation management and liver regeneration.

COVID-19 Vaccination and Disease Course in People with Multiple Sclerosis in Greece

Over the past three years, humanity faced the abrupt spread of COVID-19, responsible for a worldwide health crisis. Initially, it was believed that individuals with chronic disorders, including multiple sclerosis, were more likely to be infected and suffer a worse degree of COVID-19 disease. Therefore, data with regard to COVID-19 disease outcomes in these populations may provide additional insight with regard to the management of chronic diseases during viral pandemics. The objective of this study is to evaluate COVID-19 disease course in people with multiple sclerosis (PwMS) during the COVID-19 pandemic in Greece and explore the impact of vaccination in the outcome of SARS-CoV-2 infection in this population. Anonymized data, extracted from nationwide administrative records between February 2020 and December 2021, were retrospectively analyzed in order to identify PwMS with SARS-CoV-2 infection. Demographic data, as well as data regarding COVID-19 infection and vaccination, were additionally collected. The study sample included 2351 PwMS (65.1% females, 51.2% unvaccinated at the time of infection). A total of 260 PwMS were hospitalized, while 25 PwMS died from COVID-19 disease and its complications. Older age, male sex and the presence of comorbidities were independently associated with a higher probability of hospitalization. The risk of hospitalization was decreased in PwMS receiving some disease-modifying treatments. Anti-CD20s demonstrated high odds ratios without reaching statistical significance. Regarding fatal outcome, only age reached statistical significance. Vaccination provided a significant protective effect against hospitalization but did not exhibit a statistically significant effect on mortality.

Health disparities in COVID-19: immune and vascular changes are linked to disease severity and persist in a high-risk population in Riverside County, California

BACKGROUND

Health disparities in underserved communities, such as inadequate healthcare access, impact COVID-19 disease outcomes. These disparities are evident in Hispanic populations nationwide, with disproportionately high infection and mortality rates. Furthermore, infected individuals can develop long COVID with sustained impacts on quality of life. The goal of this study was to identify immune and endothelial factors that are associated with COVID-19 outcomes in Riverside County, a high-risk and predominantly Hispanic community, and investigate the long-term impacts of COVID-19 infection.

METHODS

112 participants in Riverside County, California, were recruited according to the following criteria: healthy control (n = 23), outpatients with moderate infection (outpatient, n = 33), ICU patients with severe infection (hospitalized, n = 33), and individuals recovered from moderate infection (n = 23). Differences in outcomes between Hispanic and non-Hispanic individuals and presence/absence of co-morbidities were evaluated. Circulating immune and vascular biomarkers were measured by ELISA, multiplex analyte assays, and flow cytometry. Follow-up assessments for long COVID, lung health, and immune and vascular changes were conducted after recovery (n = 23) including paired analyses of the same participants.

RESULTS

Compared to uninfected controls, the severe infection group had a higher proportion of Hispanic individuals (n = 23, p = 0.012) than moderate infection (n = 8, p = 0.550). Disease severity was associated with changes in innate monocytes and neutrophils, lymphopenia, disrupted cytokine production (increased IL-8 and IP-10/CXCL10 but reduced IFNλ2/3 and IFNγ), and increased endothelial injury (myoglobin, VCAM-1). In the severe infection group, a machine learning model identified LCN2/NGAL, IL-6, and monocyte activation as parameters associated with fatality while anti-coagulant therapy was associated with survival. Recovery from moderate COVID infection resulted in long-term immune changes including increased monocytes/lymphocytes and decreased neutrophils and endothelial markers. This group had a lower proportion of co-morbidities (n = 8, p = 1.0) but still reported symptoms associated with long COVID despite recovered pulmonary function.

CONCLUSION

This study indicates increased severity of COVID-19 infection in Hispanic individuals of Riverside County, California. Infection resulted in immunological and vascular changes and long COVID symptoms that were sustained for up to 11 months, however, lung volume and airflow resistance was recovered. Given the immune and behavioral impacts of long COVID, the potential for increased susceptibility to infections and decreased quality of life in high-risk populations warrants further investigation.

Long COVID as a Tauopathy: Of "Brain Fog" and "Fusogen Storms"

Long COVID, also called post-acute sequelae of SARS-CoV-2, is characterized by a multitude of lingering symptoms, including impaired cognition, that can last for many months. This symptom, often called "brain fog", affects the life quality of numerous individuals, increasing medical complications as well as healthcare expenditures. The etiopathogenesis of SARS-CoV-2-induced cognitive deficit is unclear, but the most likely cause is chronic inflammation maintained by a viral remnant thriving in select body reservoirs. These viral sanctuaries are likely comprised of fused, senescent cells, including microglia and astrocytes, that the pathogen can convert into neurotoxic phenotypes. Moreover, as the enteric nervous system contains neurons and glia, the virus likely lingers in the gastrointestinal tract as well, accounting for the intestinal symptoms of long COVID. Fusogens are proteins that can overcome the repulsive forces between cell membranes, allowing the virus to coalesce with host cells and enter the cytoplasm. In the intracellular compartment, the pathogen hijacks the actin cytoskeleton, fusing host cells with each other and engendering pathological syncytia. Cell-cell fusion enables the virus to infect the healthy neighboring cells. We surmise that syncytia formation drives cognitive impairment by facilitating the "seeding" of hyperphosphorylated Tau, documented in COVID-19. In our previous work, we hypothesized that the SARS-CoV-2 virus induces premature endothelial senescence, increasing the permeability of the intestinal and blood-brain barrier. This enables the migration of gastrointestinal tract microbes and/or their components into the host circulation, eventually reaching the brain where they may induce cognitive dysfunction. For example, translocated lipopolysaccharides or microbial DNA can induce Tau hyperphosphorylation, likely accounting for memory problems. In this perspective article, we examine the pathogenetic mechanisms and potential biomarkers of long COVID, including microbial cell-free DNA, interleukin 22, and phosphorylated Tau, as well as the beneficial effect of transcutaneous vagal nerve stimulation.

Immunogenicity of Mix-and-Match CoronaVac/BNT162b2 Regimen versus Homologous CoronaVac/CoronaVac Vaccination: A Single-Blinded, Randomized, Parallel Group Superiority Trial

(1) Background: This study aimed to compare the immunogenicity of the mix-and-match CoronaVac/BNT162b2 vaccination to the homologous CoronaVac/CoronaVac regimen. (2) Methods: We conducted a simple-blinded randomized superiority trial to measure SARS-CoV-2 neutralization antibodies and anti-spike receptor binding domain (RBD) IgG concentrations in blood samples of participants who had received the first dose of CoronaVac vaccine followed by a dose of BNT162b2 or CoronaVac vaccine. The primary endpoint for immunogenicity was the serum-neutralizing antibody level with a percentage of inhibition at 90% at 21-35 days after the boost. A difference of 25% between groups was considered clinically relevant. (3) Results: Among the 240 eligible participants, the primary endpoint data were available for 100 participants randomly allocated to the mix-and-match group versus 99 participants randomly allocated to the homologous dose group. The mix-and-match regimen elicited significantly higher levels of neutralizing antibodies (median level of 96%, interquartile range (IQR) (95-97) versus median level of 94%, IQR (81-96) and anti-spike IgG antibodies (median level of 13,460, IQR (2557-29,930) versus median level of 1190, IQR (347-4964) compared to the homologous group. Accordingly, the percentage of subjects with a percentage of neutralizing antibodies > 90% was significantly higher in the mix-and-match group (90.0%) versus the homologous (60.6%). Interestingly, no severe events were reported within 30 days after the second dose of vaccination in both groups. (4) Conclusions: Our data showed the superiority of the mix-and-match CoronaVac/BNT162b2 vaccination compared to the CoronaVac/CoronaVac regimen in terms of immunogenicity, thus constituting a proof-of-concept study supporting the use of inactivated vaccines in a mix-and-match strategy while ensuring good immunogenicity and safety.

COVID-19 induced ARDS: immunopathology and therapeutics

The coronavirus disease-2019 (COVID-19) pandemic is a significant threat in the modern era. Clinical studies show that the most common symptom of severe COVID-19 is viral pneumonia-induced acute respiratory distress syndrome (ARDS). The underlying mechanisms by which severe respiratory disease syndrome-coronavirus-2 (SARS-CoV-2) results in ARDS and how certain host factors confer an increased risk of developing severe disease remain unknown. Therefore, identifying the distinctive features of this severe and fatal disease and the therapeutic approaches to COVID-19-induced ARDS remains an immediate need to serve as a basis for best practice models of standardized ARDS treatment. This review article aims to comprehensively discuss the immunopathology of ARDS and provides an overview of the precise role of both the innate and adaptive immune system, with emphasis on the current treatment strategies being tested in the COVID-19-induced ARDS patients. This knowledge will supposedly help in revealing further mechanistic insights into understanding COVID-19-induced ARDS.

Low Dose of Ti3 C2 MXene Quantum Dots Mitigate SARS-CoV-2 Infection

MXene QDs (MQDs) have been effectively used in several fields of biomedical research. Considering the role of hyperactivation of immune system in infectious diseases, especially in COVID-19, MQDs stand as a potential candidate as a nanotherapeutic against viral infections. However, the efficacy of MQDs against SARS-CoV-2 infection has not been tested yet. In this study, Ti3 C2 MQDs are synthesized and their potential in mitigating SARS-CoV-2 infection is investigated.  Physicochemical characterization suggests that MQDs are enriched with abundance of bioactive functional groups such as oxygen, hydrogen, fluorine, and chlorine groups as well as surface titanium oxides. The efficacy of MQDs is tested in VeroE6 cells infected with SARS-CoV-2. These data demonstrate that the treatment with MQDs is able to mitigate multiplication of virus particles, only at very low doses such as 0,15 µg mL-1 . Furthermore, to understand the mechanisms of MQD-mediated anti-COVID properties, global proteomics analysis are performed and determined differentially expressed proteins between MQD-treated and untreated cells. Data reveal that MQDs interfere with the viral life cycle through different mechanisms including the Ca2 + signaling pathway, IFN-α response, virus internalization, replication, and translation. These findings suggest that MQDs can be employed to develop future immunoengineering-based nanotherapeutics strategies against SARS-CoV-2 and other viral infections.

Aged mesenchymal stem cells and inflammation: from pathology to potential therapeutic strategies

Natural ageing of organisms and corresponding age-related diseases result mainly from stem cell ageing and "inflammaging". Mesenchymal stem cells (MSCs) exhibit very high immune-regulating capacity and are promising candidates for immune-related disease treatment. However, the effect of MSC application is not satisfactory for some patients, especially in elderly individuals. With ageing, MSCs undergo many changes, including altered cell population reduction and differentiation ability, reduced migratory and homing capacity and, most important, defective immunosuppression. It is necessary to explore the relationship between the "inflammaging" and aged MSCs to prevent age-related diseases and increase the therapeutic effects of MSCs. In this review, we discuss changes in naturally ageing MSCs mainly from an inflammation perspective and propose some ideas for rejuvenating aged MSCs in future treatments.

Aggregate Index of Systemic Inflammation (AISI), Disease Severity, and Mortality in COVID-19: A Systematic Review and Meta-Analysis

Combined indices of different haematological cell types appear to be particularly promising for investigating the link between systemic inflammation and coronavirus disease 2019 (COVID-19). We conducted a systematic review and meta-analysis to assess the aggregate index of systemic inflammation (AISI), an emerging index derived from neutrophil, monocyte, platelet, and lymphocyte counts, in hospitalized COVID-19 patients with different disease severity and survival status. We searched electronic databases between the 1st of December 2019 and the 10th of June 2023 and assessed the risk of bias and the certainty of evidence. In 13 studies, severe disease/death was associated with significantly higher AISI values on admission vs. non-severe disease/survival (standard mean difference (SMD) = 0.68, 95% CI 0.38 to 0.97, p < 0.001). The AISI was also significantly associated with severe disease/death in five studies reporting odds ratios (4.39, 95% CI 2.12 to 9.06, p ˂ 0.001), but not in three studies reporting hazard ratios (HR = 1.000, 95% CI 0.999 to 1.002, p = 0.39). The pooled sensitivity, specificity, and area under the curve values for severe disease/death were 0.66 (95% CI 0.58 to 0.73), 0.78 (95% CI 0.73 to 0.83), and 0.79 (95% CI 0.76 to 0.83), respectively. Our study has shown that the AISI on admission can effectively discriminate between patients with different disease severity and survival outcome (PROSPERO registration number: CRD42023438025).

Systemic inflammation index, disease severity, and mortality in patients with COVID-19: a systematic review and meta-analysis

Introduction

An excessive systemic pro-inflammatory state increases the risk of severe disease and mortality in patients with coronavirus disease 2019 (COVID-19). However, there is uncertainty regarding whether specific biomarkers of inflammation can enhance risk stratification in this group. We conducted a systematic review and meta-analysis to investigate an emerging biomarker of systemic inflammation derived from routine hematological parameters, the systemic inflammation index (SII), in COVID-19 patients with different disease severity and survival status.

Methods

A systematic literature search was conducted in PubMed, Web of Science, and Scopus, between the 1st of December 2019 and the 15th of March 2023. Risk of bias and certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist and the Grades of Recommendation, Assessment, Development and Evaluation, respectively (PROSPERO registration number: CRD42023420517).

Results

In 39 studies, patients with a severe disease or non-survivor status had significantly higher SII values on admission compared to patients with a non-severe disease or survivor status (standard mean difference (SMD)=0.91, 95% CI 0.75 to 1.06, p<0.001; moderate certainty of evidence). The SII was also significantly associated with the risk of severe disease or death in 10 studies reporting odds ratios (1.007, 95% CI 1.001 to 1.014, p=0.032; very low certainty of evidence) and in six studies reporting hazard ratios (1.99, 95% CI 1.01 to 3.92, p=0.047; very low certainty of evidence). Pooled sensitivity, specificity, and area under the curve for severe disease or mortality were 0.71 (95% CI 0.67 to 0.75), 0.71 (95% CI 0.64 to 0.77), and 0.77 (95% CI 0.73 to 0.80), respectively. In meta-regression, significant correlations were observed between the SMD and albumin, lactate dehydrogenase, creatinine, and D-dimer.

Discussion

Our systematic review and meta-analysis has shown that the SII on admission is significantly associated with severe disease and mortality in patients with COVID-19. Therefore, this inflammatory biomarker derived from routine haematological parameters can be helpful for early risk stratification in this group.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023420517.

Comparison of C-reactive protein with distinct hyperinflammatory biomarkers in association with COVID-19 severity, mortality and SARS-CoV-2 variants

C-reactive protein (CRP) has been one of the most investigated inflammatory-biomarkers during the ongoing COVID-19 pandemics caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The severe outcome among patients with SARS-CoV-2 infection is closely related to the cytokine storm and the hyperinflammation responsible for the acute respiratory distress syndrome and multiple organ failure. It still remains a challenge to determine which of the hyperinflammatory biomarkers and cytokines are the best predictors for disease severity and mortality in COVID-19 patients. Therefore, we evaluated and compared the outcome prediction efficiencies between CRP, the recently reported inflammatory modulators (suPAR, sTREM-1, HGF), and the classical biomarkers (MCP-1, IL-1β, IL-6, NLR, PLR, ESR, ferritin, fibrinogen, and LDH) in patients confirmed with SARS-CoV-2 infection at hospital admission. Notably, patients with severe disease had higher serum levels of CRP, suPAR, sTREM-1, HGF and classical biomarkers compared to the mild and moderate cases. Our data also identified CRP, among all investigated analytes, to best discriminate between severe and non-severe forms of disease, while LDH, sTREM-1 and HGF proved to be excellent mortality predictors in COVID-19 patients. Importantly, suPAR emerged as a key molecule in characterizing the Delta variant infections.

Generalizing the Wells-Riley Infection Probability: A Superstatistical Scheme for Indoor Infection Risk Estimation

Recent evidence supports that air is the main transmission pathway of the recently identified SARS-CoV-2 coronavirus that causes COVID-19 disease. Estimating the infection risk associated with an indoor space remains an open problem due to insufficient data concerning COVID-19 outbreaks, as well as, methodological challenges arising from cases where environmental (i.e., out-of-host) and immunological (i.e., within-host) heterogeneities cannot be neglected. This work addresses these issues by introducing a generalization of the elementary Wells-Riley infection probability model. To this end, we adopted a superstatistical approach where the exposure rate parameter is gamma-distributed across subvolumes of the indoor space. This enabled us to construct a susceptible (S)-exposed (E)-infected (I) dynamics model where the Tsallis entropic index q quantifies the degree of departure from a well-mixed (i.e., homogeneous) indoor-air-environment state. A cumulative-dose mechanism is employed to describe infection activation in relation to a host's immunological profile. We corroborate that the six-foot rule cannot guarantee the biosafety of susceptible occupants, even for exposure times as short as 15 min. Overall, our work seeks to provide a minimal (in terms of the size of the parameter space) framework for more realistic indoor SEI dynamics explorations while highlighting their Tsallisian entropic origin and the crucial yet elusive role that the innate immune system can play in shaping them. This may be useful for scientists and decision makers interested in probing different indoor biosafety protocols more thoroughly and comprehensively, thus motivating the use of nonadditive entropies in the emerging field of indoor space epidemiology.

Ketogenic Diet and Ketone Bodies as Clinical Support for the Treatment of SARS-CoV-2-Review of the Evidence

One of the proposed nutritional therapies to support drug therapy in COVID-19 is the use of a ketogenic diet (KD) or ketone bodies. In this review, we summarized the evidence from tissue, animal, and human models and looked at the mechanisms of action of KD/ketone bodies against COVID-19. KD/ketone bodies were shown to be effective at the stage of virus entry into the host cell. The use of β-hydroxybutyrate (BHB), by preventing the metabolic reprogramming associated with COVID-19 infection and improving mitochondrial function, reduced glycolysis in CD4+ lymphocytes and improved respiratory chain function, and could provide an alternative carbon source for oxidative phosphorylation (OXPHOS). Through multiple mechanisms, the use of KD/ketone bodies supported the host immune response. In animal models, KD resulted in protection against weight loss and hypoxemia, faster recovery, reduced lung injury, and resulted in better survival of young mice. In humans, KD increased survival, reduced the need for hospitalization for COVID-19, and showed a protective role against metabolic abnormalities after COVID-19. It appears that the use of KD and ketone bodies may be considered as a clinical nutritional intervention to assist in the treatment of COVID-19, despite the fact that numerous studies indicate that SARS-CoV-2 infection alone may induce ketoacidosis. However, the use of such an intervention requires strong scientific validation.

Ultrastructural study confirms the formation of single and heterotypic syncytial cells in bronchoalveolar fluids of COVID-19 patients

BACKGROUND

SARS-CoV-2 was reported to induce cell fusions to form multinuclear syncytia that might facilitate viral replication, dissemination, immune evasion, and inflammatory responses. In this study, we have reported the types of cells involved in syncytia formation at different stages of COVID-19 disease through electron microscopy.

METHODS

Bronchoalveolar fluids from the mild (n = 8, SpO2 > 95%, no hypoxia, within 2-8 days of infection), moderate (n = 8, SpO2 90% to ≤ 93% on room air, respiratory rate ≥ 24/min, breathlessness, within 9-16 days of infection), and severe (n = 8, SpO2 < 90%, respiratory rate > 30/min, external oxygen support, after 17th days of infection) COVID-19 patients were examined by PAP (cell type identification), immunofluorescence (for the level of viral infection), scanning (SEM), and transmission (TEM) electron microscopy to identify the syncytia.

RESULTS

Immunofluorescence studies (S protein-specific antibodies) from each syncytium indicate a very high infection level. We could not find any syncytial cells in mildly infected patients. However, identical (neutrophils or type 2 pneumocytes) and heterotypic (neutrophils-monocytes) plasma membrane initial fusion (indicating initiation of fusion) was observed under TEM in moderately infected patients. Fully matured large-size (20-100 μm) syncytial cells were found in severe acute respiratory distress syndrome (ARDS-like) patients of neutrophils, monocytes, and macrophage origin under SEM.

CONCLUSIONS

This ultrastructural study on the syncytial cells from COVID-19 patients sheds light on the disease's stages and types of cells involved in the syncytia formations. Syncytia formation was first induced in type II pneumocytes by homotypic fusion and later with haematopoetic cells (monocyte and neutrophils) by heterotypic fusion in the moderate stage (9-16 days) of the disease. Matured syncytia were reported in the late phase of the disease and formed large giant cells of 20 to 100 μm.

TLRs: Innate Immune Sentries against SARS-CoV-2 Infection

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been responsible for a devastating pandemic since March 2020. Toll-like receptors (TLRs), crucial components in the initiation of innate immune responses to different pathogens, trigger the downstream production of pro-inflammatory cytokines, interferons, and other mediators. It has been demonstrated that they contribute to the dysregulated immune response observed in patients with severe COVID-19. TLR2, TLR3, TLR4 and TLR7 have been associated with COVID-19 severity. Here, we review the role of TLRs in the etiology and pathogenesis of COVID-19, including TLR7 and TLR3 rare variants, the L412F polymorphism in TLR3 that negatively regulates anti-SARS-CoV-2 immune responses, the TLR3-related cellular senescence, the interaction of TLR2 and TLR4 with SARS-CoV-2 proteins and implication of TLR2 in NET formation by SARS-CoV-2. The activation of TLRs contributes to viral clearance and disease resolution. However, TLRs may represent a double-edged sword which may elicit dysregulated immune signaling, leading to the production of proinflammatory mediators, resulting in severe disease. TLR-dependent excessive inflammation and TLR-dependent antiviral response may tip the balance towards the former or the latter, altering the equilibrium that drives the severity of disease.

More than a key-the pathological roles of SARS-CoV-2 spike protein in COVID-19 related cardiac injury

Cardiac injury is common in hospitalized coronavirus disease 2019 (COVID-19) patients and cardiac abnormalities have been observed in a significant number of recovered COVID-19 patients, portending long-term health issues for millions of infected individuals. To better understand how Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2, CoV-2 for short) damages the heart, it is critical to fully comprehend the biology of CoV-2 encoded proteins, each of which may play multiple pathological roles. For example, CoV-2 spike glycoprotein (CoV-2-S) not only engages angiotensin converting enzyme II (ACE2) to mediate virus infection but also directly activates immune responses. In this work, the goal is to review the known pathological roles of CoV-2-S in the cardiovascular system, thereby shedding lights on the pathogenesis of COVID-19 related cardiac injury.

SARS-CoV-2 infection and immune responses

The recent pandemic caused by the SARS-CoV-2 virus continues to be an enormous global challenge faced by the healthcare sector. Availability of new vaccines and drugs targeting SARS-CoV-2 and sequelae of COVID-19 has given the world hope in ending the pandemic. However, the emergence of mutations in the SARS-CoV-2 viral genome every couple of months in different parts of world is a persistent danger to public health. Currently there is no single treatment to eradicate the risk of COVID-19. The widespread transmission of SARS-CoV-2 due to the Omicron variant necessitates continued work on the development and implementation of effective vaccines. Moreover, there is evidence that mutations in the receptor domain of the SARS-CoV-2 spike glycoprotein led to the decrease in current vaccine efficacy by escaping antibody recognition. Therefore, it is essential to actively identify the mechanisms by which SARS-CoV-2 evades the host immune system, study the long-lasting effects of COVID-19 and develop therapeutics targeting SARS-CoV-2 infections in humans and preclinical models. In this review, we describe the pathogenic mechanisms of SARS-CoV-2 infection as well as the innate and adaptive host immune responses to infection. We address the ongoing need to develop effective vaccines that provide protection against different variants of SARS-CoV-2, as well as validated endpoint assays to evaluate the immunogenicity of vaccines in the pipeline, medications, anti-viral drug therapies and public health measures, that will be required to successfully end the COVID-19 pandemic.

Differential regulatory T cell signature after recovery from mild COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by a range of symptoms in which host immune response have been associated with disease progression. However, the putative role of regulatory T cells (Tregs) in determining COVID-19 outcomes has not been thoroughly investigated. Here, we compared peripheral Tregs between volunteers not previously infected with SARS-CoV-2 (healthy control [HC]) and volunteers who recovered from mild (Mild Recovered) and severe (Severe Recovered) COVID-19. Peripheral blood mononuclear cells (PBMC) were stimulated with SARS-CoV-2 synthetic peptides (Pool Spike CoV-2 and Pool CoV-2) or staphylococcal enterotoxin B (SEB). Results of a multicolor flow cytometric assay showed higher Treg frequency and expression of IL-10, IL-17, perforin, granzyme B, PD-1, and CD39/CD73 co-expression in Treg among the PBMC from the Mild Recovered group than in the Severe Recovered or HC groups for certain SARS-CoV-2 related stimulus. Moreover, Mild Recovered unstimulated samples presented a higher Tregs frequency and expression of IL-10 and granzyme B than did that of HC. Compared with Pool CoV-2 stimuli, Pool Spike CoV-2 reduced IL-10 expression and improved PD-1 expression in Tregs from volunteers in the Mild Recovered group. Interestingly, Pool Spike CoV-2 elicited a decrease in Treg IL-17+ frequency in the Severe Recovered group. In HC, the expression of latency-associated peptide (LAP) and cytotoxic granule co-expression by Tregs was higher in Pool CoV-2 stimulated samples. While Pool Spike CoV-2 stimulation reduced the frequency of IL-10+ and CTLA-4+ Tregs in PBMC from volunteers in the Mild Recovered group who had not experienced certain symptoms, higher levels of perforin and perforin+granzyme B+ co-expression by Tregs were found in the Mild Recovered group in volunteers who had experienced dyspnea. Finally, we found differential expression of CD39 and CD73 among volunteers in the Mild Recovered group between those who had and had not experienced musculoskeletal pain. Collectively, our study suggests that changes in the immunosuppressive repertoire of Tregs can influence the development of a distinct COVID-19 clinical profile, revealing that a possible modulation of Tregs exists among volunteers of the Mild Recovered group between those who did and did not develop certain symptoms, leading to mild disease.