Regulation of the Expression of SARS-CoV-2 Receptor Angiotensin-Converting Enzyme 2 in Nasal Mucosa

Fucoidan from Ascophyllum nodosum and Undaria pinnatifida attenuate SARS-CoV-2 infection in vitro and in vivo by suppressing ACE2 and alleviating inflammation

The global healthcare challenge posed by COVID-19 necessitates the continuous exploration for novel antiviral agents. Fucoidans have demonstrated antiviral activity. However, the underlying structure-activity mechanism responsible for the inhibitory activity of fucoidans from Ascophyllum nodosum (FUCA) and Undaria pinnatifida (FUCU) against SARS-CoV-2 remains unclear. FUCA was characterized as a homopolymer with a backbone structure of repeating (1 → 3) and (1 → 4) linked α-l-fucopyranose residues, whereas FUCU was a heteropolysaccharide composed of Fuc1-3Gal1-6 repeats. Furthermore, FUCA demonstrated significantly higher anti-SARS-CoV-2 activity than FUCU (EC50: 48.66 vs 69.52 μg/mL), suggesting the degree of branching rather than sulfate content affected the antiviral activity. Additionally, FUCA exhibited a dose-dependent inhibitory effect on ACE2, surpassing the inhibitory activity of FUCU. In vitro, both FUCA and FUCU treatments downregulated the expression of pro-inflammatory cytokines (IL-6, IFN-α, IFN-γ, and TNF-α) and anti-inflammatory cytokines (IL-10 and IFN-β) induced by viral infection. In hamsters, FUCA demonstrated greater effectiveness in attenuating lung and gastrointestinal injury and reducing ACE2 expression, compared to FUCU. Analysis of the 16S rRNA gene sequencing revealed that only FUCU partially alleviated the gut microbiota dysbiosis caused by SARS-CoV-2. Consequently, our study provides a scientific basis for considering fucoidans as poteintial prophylactic food components against SARS-CoV-2.

FGF7 enhances the expression of ACE2 in human islet organoids aggravating SARS-CoV-2 infection

The angiotensin-converting enzyme 2 (ACE2) is a primary cell surface viral binding receptor for SARS-CoV-2, so finding new regulatory molecules to modulate ACE2 expression levels is a promising strategy against COVID-19. In the current study, we utilized islet organoids derived from human embryonic stem cells (hESCs), animal models and COVID-19 patients to discover that fibroblast growth factor 7 (FGF7) enhances ACE2 expression within the islets, facilitating SARS-CoV-2 infection and resulting in impaired insulin secretion. Using hESC-derived islet organoids, we demonstrated that FGF7 interacts with FGF receptor 2 (FGFR2) and FGFR1 to upregulate ACE2 expression predominantly in β cells. This upregulation increases both insulin secretion and susceptibility of β cells to SARS-CoV-2 infection. Inhibiting FGFR counteracts the FGF7-induced ACE2 upregulation, subsequently reducing viral infection and replication in the islets. Furthermore, retrospective clinical data revealed that diabetic patients with severe COVID-19 symptoms exhibited elevated serum FGF7 levels compared to those with mild symptoms. Finally, animal experiments indicated that SARS-CoV-2 infection increased pancreatic FGF7 levels, resulting in a reduction of insulin concentrations in situ. Taken together, our research offers a potential regulatory strategy for ACE2 by controlling FGF7, thereby protecting islets from SARS-CoV-2 infection and preventing the progression of diabetes in the context of COVID-19.

Nasopharyngeal angiotensin converting enzyme 2 (ACE2) expression as a risk-factor for SARS-CoV-2 transmission in concurrent hospital associated outbreaks

BACKGROUND

Widespread human-to-human transmission of the severe acute respiratory syndrome coronavirus two (SARS-CoV-2) stems from a strong affinity for the cellular receptor angiotensin converting enzyme two (ACE2). We investigate the relationship between a patient's nasopharyngeal ACE2 transcription and secondary transmission within a series of concurrent hospital associated SARS-CoV-2 outbreaks in British Columbia, Canada.

METHODS

Epidemiological case data from the outbreak investigations was merged with public health laboratory records and viral lineage calls, from whole genome sequencing, to reconstruct the concurrent outbreaks using infection tracing transmission network analysis. ACE2 transcription and RNA viral load were measured by quantitative real-time polymerase chain reaction. The transmission network was resolved to calculate the number of potential secondary cases. Bivariate and multivariable analyses using Poisson and Negative Binomial regression models was performed to estimate the association between ACE2 transcription the number of SARS-CoV-2 secondary cases.

RESULTS

The infection tracing transmission network provided n = 76 potential transmission events across n = 103 cases. Bivariate comparisons found that on average ACE2 transcription did not differ between patients and healthcare workers (P = 0.86). High ACE2 transcription was observed in 98.6% of transmission events, either the primary or secondary case had above average ACE2. Multivariable analysis found that the association between ACE2 transcription (log2 fold-change) and the number of secondary transmission events differs between patients and healthcare workers. In health care workers Negative Binomial regression estimated that a one-unit change in ACE2 transcription decreases the number of secondary cases (β = -0.132 (95%CI: -0.255 to -0.0181) adjusting for RNA viral load. Conversely, in patients a one-unit change in ACE2 transcription increases the number of secondary cases (β = 0.187 (95% CI: 0.0101 to 0.370) adjusting for RNA viral load. Sensitivity analysis found no significant relationship between ACE2 and secondary transmission in health care workers and confirmed the positive association among patients.

CONCLUSION

Our study suggests that ACE2 transcription has a positive association with SARS-CoV-2 secondary transmission in admitted inpatients, but not health care workers in concurrent hospital associated outbreaks, and it should be further investigated as a risk-factor for viral transmission.

COVID-19 and Nutrition: Focus on Chronic Kidney Disease

Some chronic diseases, including chronic kidney disease (CKD), may be associated with poor outcomes, including a high rate of hospitalization and death after COVID-19 infection. In addition to the vaccination program, diet intervention is essential for boosting immunity and preventing complications. A healthy diet containing bioactive compounds may help mitigate inflammatory responses and oxidative stress caused by COVID-19. In this review, we discuss dietary interventions for mitigating COVID-19 complications, including in persons with CKD, which can worsen COVID-19 symptoms and its clinical outcomes, while diet may help patients with CKD to resist the ravages of COVID-19 by improving the immune system, modulating gut dysbiosis, mitigating COVID-19 complications, and reducing hospitalization and mortality. The concept of food as medicine, also known as culinary medicine, for patients with CKD can be extrapolated to COVID-19 infection because healthy foods and nutraceuticals have the potential to exert an important antiviral, anti-inflammatory, and antioxidant role.

Understanding olfactory dysfunction in the COVID-19 era: insights from a cross-sectional survey of the Saudi community

Background and objectives

COVID-19 has emerged as a public health emergency caused by the coronavirus 2 (SARS-CoV2). However, only a few studies have reported that anosmia is an early predictor of COVID-19. Therefore, this study aimed to assess the current level of knowledge regarding smell dysfunction in COVID-19 era in Saudi community.

Materials and methods

An online survey was conducted using Survey Monkeys in Saudi Arabia. The survey was distributed through Twitter and WhatsApp. The questionnaire included individuals' demographic information, such as sex, age, residence, income, and qualifications, as well as their knowledge of the early symptoms of COVID-19. ANOVA and Mann-Whitney U-test were conducted to analyze the data. There were twelve items on knowledge dimensions which were assessed through five-point Likert scale.

Results

In total, 809 respondents completed the questionnaire. Among them, 658 (81.3%) had no knowledge of how sudden loss of or change in the sense of smell can be the only symptom of COVID-19. However, most participants, 738 (91.2%), knew that fever was a symptom of COVID-19. Similarly, 707 (87.4%) and 772 (95.5%) participants knew that cough and shortness of breath were the major symptoms of COVID-19, respectively. In addition, 395 (48.3%) participants had no information regarding taste changes as a symptom of COVID-19. Notably, participants who were female, married, or diagnosed with COVID-19 had significantly greater knowledge of smell-related issues due to COVID-19 than males, unmarried, and healthy/those without COVID-19.

Conclusion

This study revealed that the Saudi population has an fairly good level of knowledge regarding common COVID-19 symptoms as more than 90% of the participants understood symptoms of COVID-19, but less acceptable knowledge regarding smell and taste dysfunction as more than 80% had no knowledge of change in olfactory and taste function was due to COVID-19.

Nasal application of sesame oil-based Anu taila as 'biological mask' for respiratory health during COVID-19

This article narrates the potential role of sesame oil-based Anu taila for respiratory health and the prevention of COVID-19. Ayurveda recommends the use of sesame oil and A. taila as a part of daily routine (dinacharya) for oral gargling and transnasal application (Nasya) for preventing upper respiratory tract infections. Recent studies on COVID-19 have elucidated the activity of certain fatty acids in restricting viral binding. Based on the evidence gathered from in-silico, pre-clinical, and pharmacological studies as well as references from classical textbooks of Ayurveda, this article infers that the transnasal application of sesame oil and/or A. taila could provide resilience/protection to the respiratory system. It can act as a 'biological mask' to prevent respiratory infections like COVID-19. Detailed pharmacological study can give fuller confirmation of our informed "inference" that A. taila offers a cost-effective intervention for the prevention of COVID-19 like infections of the upper respiratory tract.

Lipid alternations in the plasma of COVID-19 patients with various clinical presentations

Background

COVID-19 is a highly infectious respiratory disease that can manifest in various clinical presentations. Although many studies have reported the lipidomic signature of COVID-19, the molecular changes in asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals remain elusive.

Methods

This study combined a comprehensive lipidomic analysis of 220 plasma samples from 166 subjects: 62 healthy controls, 16 asymptomatic infections, and 88 COVID-19 patients. We quantified 732 lipids separately in this cohort. We performed a difference analysis, validated with machine learning models, and also performed GO and KEGG pathway enrichment analysis using differential lipids from different control groups.

Results

We found 175 differentially expressed lipids associated with SASR-CoV-2 infection, disease severity, and viral persistence in patients with COVID-19. PC (O-20:1/20:1), PC (O-20:1/20:0), and PC (O-18:0/18:1) better distinguished asymptomatic infected individuals from normal individuals. Furthermore, some patients tested positive for SARS-CoV-2 nucleic acid by RT-PCR but did not become negative for a longer period of time (≥60 days, designated here as long-term nucleic acid test positive, LTNP), whereas other patients became negative for viral nucleic acid in a shorter period of time (≤45 days, designated as short-term nucleic acid test positive, STNP). We have found that TG (14:1/14:1/18:2) and FFA (4:0) were differentially expressed in LTNP and STNP.

Conclusion

In summary, the integration of lipid information can help us discover novel biomarkers to identify asymptomatic individuals and further deepen our understanding of the molecular pathogenesis of COVID-19.

Investigation of Cognitive Impairment in the Course of Post-COVID Syndrome

(1) Background: The study presents results from an investigation of cognitive impairment in patients hospitalized in the first psychiatric clinic in Bulgaria to treat patients with COVID-19 during the pandemic period between 2020 and 2022. One hundred and twenty patients who had recovered from acute COVID-19 infection (up to 12 weeks ago) and had no previous history of cognitive impairment participated in the study. In 23 of them (19.17%), disturbance of cognitive functioning was observed. (2) Methods: All 23 patients underwent neuropsychological (Luria's test, Platonov's Maze test, MMSE, Boston Naming test) and neuroimaging examinations. Only seven of them had evidence of cortical atrophy on CT/MRI images. The most significantly demonstrative image of one of those patients is presented. (3) Results: The neuropsychological testing results of both groups show a certain decrease in fixation and memory retention as well as in the range, concentration, distribution and switching of attention. Deviations from the norm on the MMSE, as well as on the Boston Naming Test, were found in the group of patients with cortical atrophy (mild to moderate aphasia). Neuroprotective agents such as Citicoline, Piracetam and Memantine were prescribed to the patients with evident cortical atrophy. After 3 months, positive results of the neuropsychological examination were reported in both groups. (4) Conclusions: Although there are limited data on the benefit of prescribing pro-cognitive agents in the post-COVID period, our clinical experience suggests that it might be useful in the recovery process from the infection's consequences on cognition for patients with brain pathology.

Short-chain fatty acids profile in patients with SARS-CoV-2: A case-control study

Background and Aims

SARS-CoV-2, as a new pandemic disease, affected the world. Short-chain fatty acids (SCFAs) such as acetic, propionic, and butyric acids are the main metabolites of human gut microbiota. The positive effects of SCFAs have been shown in infections caused by respiratory syncytial virus, adenovirus, influenza, and rhinovirus. Therefore, this study aimed to evaluate the concentration of SCFAs in patients with SARS-CoV-2 compared with the healthy group.

Methods

This research was designed based on a case and control study. Twenty healthy individuals as the control group and 20 persons admitted to the hospital with a positive test of coronavirus disease (COVID-19) real-time polymerase chain reaction were included in the study as the patient group from September 2021 to October 2021, in Tabriz, Iran. Stool specimens were collected from volunteers, and analysis of SCFAs was carried out by a high-performance liquid chromatography system.

Results

The amount of acetic acid in the healthy group was 67.88 ± 23.09 μmol/g, while in the group of patients with COVID-19 was 37.04 ± 13.29 μmol/g. Therefore, the concentration of acetic acid in the patient group was significantly (p < 0.001) lower than in the healthy group. Propionic and butyric acid were present in a higher amount in the control group compared with the case group; however, this value was not statistically significant (p > 0.05).

Conclusion

This study showed that the concentration of acetic acid as the metabolite caused by gut microbiota is significantly disturbed in patients with COVID-19. Therefore, therapeutic interventions based on gut microbiota metabolites in future research may be effective against COVID-19.

Acetate-encapsulated Linolenic Acid Liposomes Reduce SARS-CoV-2 and RSV Infection

Emergent Coronaviridae viruses, such as SARS-CoV-1 in 2003, MERS-CoV in 2012, and SARS-CoV-2 (CoV-2) in 2019, have caused millions of deaths. These viruses have added to the existing respiratory infection burden along with respiratory syncytial virus (RSV) and influenza. There are limited therapies for respiratory viruses, with broad-spectrum treatment remaining an unmet need. Since gut fermentation of fiber produces short-chain fatty acids (SCFA) with antiviral potential, developing a fatty acid-based broad-spectrum antiviral was investigated. Molecular docking of fatty acids showed α-linolenic acid (ALA) is likely to interact with CoV-2-S, NL63-CoV-S, and RSV-F, and an ALA-containing liposome interacted with CoV-2 directly, degrading the particle. Furthermore, a combination of ALA and a SCFA-acetate synergistically inhibited CoV2-N expression and significantly reduced viral plaque formation and IL-6 and IL-1β transcript expression in Calu-3 cells, while increasing the expression of IFN-β. A similar effect was also observed in RSV-infected A549 cells. Moreover, mice infected with a murine-adapted SARS-CoV-2 (MA10) and treated with an ALA-liposome encapsulating acetate showed significant reductions in plaque-forming units present in lung tissue and in infection-associated lung inflammation and cytokines. Taken together, these results demonstrate that the ALA liposome-encapsulating acetate can be a promising broad antiviral therapy against respiratory infections.

A Review of the Role of Pollen in COVID-19 Infection

There is current interest in the role of ambient pollen in the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2 or COVID-19) infection risk. The aim of this review is to summarise studies published up until January 2023 investigating the relationship between airborne pollen and the risk of COVID-19 infection. We found conflicting evidence, with some studies showing that pollen may increase the risk of COVID-19 infection by acting as a carrier, while others showed that pollen may reduce the risk by acting as an inhibiting factor. A few studies reported no evidence of an association between pollen and the risk of infection. A major limiting factor of this research is not being able to determine whether pollen contributed to the susceptibility to infection or just the expression of symptoms. Hence, more research is needed to better understand this highly complex relationship. Future investigations should consider individual and sociodemographic factors as potential effect modifiers when investigating these associations. This knowledge will help to identify targeted interventions.

Recent developments in the immunopathology of COVID-19

There has been an important change in the clinical characteristics and immune profile of Coronavirus disease 2019 (COVID-19) patients during the pandemic thanks to the extensive vaccination programs. Here, we highlight recent studies on COVID-19, from the clinical and immunological characteristics to the protective and risk factors for severity and mortality of COVID-19. The efficacy of the COVID-19 vaccines and potential allergic reactions after administration are also discussed. The occurrence of new variants of concerns such as Omicron BA.2, BA.4, and BA.5 and the global administration of COVID-19 vaccines have changed the clinical scenario of COVID-19. Multisystem inflammatory syndrome in children (MIS-C) may cause severe and heterogeneous disease but with a lower mortality rate. Perturbations in immunity of T cells, B cells, and mast cells, as well as autoantibodies and metabolic reprogramming may contribute to the long-term symptoms of COVID-19. There is conflicting evidence about whether atopic diseases, such as allergic asthma and rhinitis, are associated with a lower susceptibility and better outcomes of COVID-19. At the beginning of pandemic, the European Academy of Allergy and Clinical Immunology (EAACI) developed guidelines that provided timely information for the management of allergic diseases and preventive measures to reduce transmission in the allergic clinics. The global distribution of COVID-19 vaccines and emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with reduced pathogenic potential dramatically decreased the morbidity, severity, and mortality of COVID-19. Nevertheless, breakthrough infection remains a challenge for disease control. Hypersensitivity reactions (HSR) to COVID-19 vaccines are low compared to other vaccines, and these were addressed in EAACI statements that provided indications for the management of allergic reactions, including anaphylaxis to COVID-19 vaccines. We have gained a depth knowledge and experience in the over 2 years since the start of the pandemic, and yet a full eradication of SARS-CoV-2 is not on the horizon. Novel strategies are warranted to prevent severe disease in high-risk groups, the development of MIS-C and long COVID-19.

Nasal Microbiome and Its Interaction with the Host in Childhood Asthma

Childhood asthma is a major chronic non-communicable disease in infants and children, often triggered by respiratory tract infections. The nasal cavity is a reservoir for a broad variety of commensal microbes and potential pathogens associated with respiratory illnesses including asthma. A healthy nasal microenvironment has protective effects against respiratory tract infections. The first microbial colonisation in the nasal region is initiated immediately after birth. Subsequently, colonisation by nasal microbiota during infancy plays important roles in rapidly establishing immune homeostasis and the development and maturation of the immune system. Dysbiosis of microbiota residing in the mucosal surfaces, such as the nasopharynx and guts, triggers immune modulation, severe infection, and exacerbation events. Nasal microbiome dysbiosis is related to the onset of symptomatic infections. Dynamic interactions between viral infections and the nasal microbiota in early life affect the later development of respiratory infections. In this review, we summarise the existing findings related to nasal microbiota colonisation, dynamic variations, and host–microbiome interactions in childhood health and respiratory illness with a particular examination of asthma. We also discuss our current understanding of biases produced by environmental factors and technical concerns, the importance of standardised research methods, and microbiome modification for the prevention or treatment of childhood asthma. This review lays the groundwork for paying attention to an essential but less emphasized topic and improves the understanding of the overall composition, dynamic changes, and influence of the nasal microbiome associated with childhood asthma.

Chronic Rhinosinusitis and COVID-19

The COVID-19 pandemic has raised awareness about olfactory dysfunction, although a loss of smell was present in the general population before COVID-19. Chronic rhinosinusitis (CRS) is a common upper airway chronic inflammatory disease that is also one of the most common causes of olfactory dysfunction. It can be classified into different phenotypes (ie, with and without nasal polyps) and endotypes (ie, type 2 and non-type 2 inflammation). However, scientific information regarding CRS within the context of COVID-19 is still scarce. This review focuses on (1) the potential effects of severe acute respiratory syndrome coronavirus 2 infection on CRS symptoms, including a loss of smell, and comorbidities; (2) the pathophysiologic mechanisms involved in the olfactory dysfunction; (3) CRS diagnosis in the context of COVID-19, including telemedicine; (4) the protective hypothesis of CRS in COVID-19; and (5) the efficacy and safety of therapeutic options for CRS within the context of COVID-19.

Anosmia (smell failure) and dysgeusia (taste distortion) in COVID-19: it is genetic

The COVID-19 pandemic is a very contagious respiratory illness with has affected millions of individuals worldwide. In addition to the well-known symptoms of any respiratory virus, COVID-19 can present with anosmia (failure to smell) and dysgeusia (distortion of the sense of taste). It appears to be a genetic link to the biological mechanisms underlying COVID-19-related anosmia and dysgeusia. Significant locus in the vicinity of the UGT2A1 and UGT2A2 genes are currently considered as the main culprit of the symptoms. However, more studies are needed to delineate a clear pathophysiology.Communicated by Ramaswamy H. Sarma.

Short-chain fatty acids-microbiota crosstalk in the coronavirus disease (COVID-19)

The novel coronavirus disease (COVID-19) still remains a major challenge to the health-care systems worldwide, inciting ongoing search for pharmaceutical and non-pharmaceutical interventions which could benefit patients already infected with SARS-CoV-2 or at increased risk thereof. Although SARS-CoV-2 primarily affects the respiratory system, it may also infect other organs and systems, including gastrointestinal tract, where it results in microbial dysbiosis. There is an emerging understanding of the role the gut microbiota plays in maintaining immune homeostasis, both inside the gastrointestinal tract and beyond (i.e. through gut-lung and gut-brain axes). One family of compounds with recognized immunomodulatory and anti-inflammatory properties are short chain fatty acids (SCFAs). SCFAs are believed that they have a protective effect in case of gastrointestinal diseases. Moreover, they are responsible for maintaining proper intestinal barrier and they take part in relevant immune functions. This review presents mechanisms of action and potential benefits of SCFA-based probiotics and direct SCFA supplementation as a strategy to support immune function amid the COVID-19 pandemic.