Assessment of mucociliary clearance as an indicator of nasal function in patients with COVID-19: a cross-sectional study

Optical Imaging of Cilia in the Head and Neck

Background/Objectives: Cilia are hair-like organelles with various mechanosensory and chemosensory functions. In particular, motile cilia generate directional fluid flow important for multiple processes. Motile ciliopathies have serious clinical implications, including developmental and respiratory disorders. Evaluating the most suitable imaging methods for studying ciliary structure and function has great clinical significance. Methods: Here, we provide an overview of ciliary function, imaging modalities, and applications in ciliopathic diseases. Results: Optical imaging has become a crucial tool for studying ciliary structure and function, providing high-resolution, non-invasive imaging capabilities that are valuable for in vivo applications. Optical coherence tomography (OCT) is well suited for the visualization of ciliary anatomy and quantitative studies of microfluidic flow. Conclusions: A deeper understanding of ciliary biology can lead to novel approaches in diagnosing, treating, and monitoring ciliopathies, contributing to more effective and individualized care.

Increased serum ferritin is associated with severity of orbital disease in COVID-19-associated rhino-orbito-cerebral mucormycosis: A quantitative analysis

CONTEXT

Effect of serum ferritin on severity of coronavirus disease 2019 (COVID-19)-associated rhino-orbito-cerebral mucormycosis.

PURPOSE

To study the association between increased serum ferritin and severity of orbital disease in COVID-19-associated rhino-orbito-cerebral mucormycosis.

SETTINGS AND DESIGN

A cross-sectional study.

METHODS

Hundred ( n ) out of 155 treatment-naive patients of COVID-19 infection presenting with the signs and symptoms of rhino-orbito-cerebral mucormycosis were enrolled in study. Based on the classification proposed by Honavar, the study patients were classified into four stages: Stage 1: involvement of the nasal mucosa ( n = 11), Stage 2: involvement of paranasal sinuses ( n = 14), Stage 3: involvement of the orbit ( n = 37), Stage 4: involvement of the central nervous system ( n = 38). Stage 3 was further divided into four substages: 3a: nasolacrimal duct, medial orbit, vision unaffected ( n = 4); 3b: diffuse orbital involvement (>1 quadrant or >2 structures), vision unaffected ( n = 15); 3c: central retinal artery occlusion or ophthalmic artery occlusion, superior ophthalmic vein thrombosis, involvement of superior orbital fissure, inferior orbital fissure, orbital apex, diminution or loss of vision ( n = 13); 3d: bilateral orbital involvement ( n = 5). Fasting blood sugar (FBS), postprandial blood sugar (PPBS), and inflammatory markers (serum ferritin, interleukin-6, C-reactive protein, and D-dimer) were assessed. Serum level of ferritin was analyzed by using chemiluminescence immunoassay method.

RESULTS

Mean FBS (mg/dl) was 165.03 ± 70.43 for stage 1, 185.67 ± 64.82 for stage 2, 159.05 ± 68.60 for stage 3, and 158.20 ± 62.05 for stage 4. Mean PPBS (mg/dl) was 238.70 ± 141.29 for stage 1, 252 ± 103.69 for stage 2, 257.09 ± 103.48 for stage 3, and 229.53 ± 76.81 for stage 4. Mean serum ferritin (μg/l) was 302.67 ± 266.95 in stage 1, 444.19 ± 116.36 in stage 2, 504.85 ± 205.99 in stage 3, and 825.95 ± 777.30 in stage 4. A statistically significant increase in serum ferritin levels with severity of disease ( P = 0.005) was noted. Similar trend was observed in substages of stage 3. Pearson correlation analysis showed a positive correlation between serum ferritin and severity of disease ( P = 0.0007).

CONCLUSION

Increased serum ferritin was significantly independently associated with severity of orbital disease in COVID-19-associated rhino-orbito-cerebral mucormycosis.

Nasal Obstruction Symptom Evaluation Score Analysis: Exploring Nasal Function in Premenopausal versus Postmenopausal Indian Women

Background

Menopause brings about significant hormonal changes that can affect various aspects of women's health, including nasal function. However, the specific impact of menopause on nasal health in Indian women remains underexplored. This study aims to compare nasal function using the Nasal Obstruction Symptom Evaluation (NOSE) score between premenopausal and postmenopausal Indian women.

Materials and Methods

A comparative cross-sectional study was conducted involving 107 premenopausal and 111 postmenopausal women recruited from a tertiary care hospital in India. Demographic data, medical history, and NOSE scores were collected. Statistical analyses including Wilcoxon rank-sum test, Chi-squared test, logistic regression, and receiver operating characteristic curve analysis were performed.

Results

Postmenopausal women were significantly older with higher body mass index (BMI) compared to premenopausal women. Postmenopausal women consistently had higher NOSE scores indicating worse nasal function across various time points. Logistic regression revealed menopausal status as a significant predictor of severe nasal obstruction (odds ratio: 1.45, 95% confidence interval: 1.10-1.90, P = 0.015), independent of age, BMI, and other factors.

Conclusion

Menopause is associated with a significant decline in nasal function in Indian women, as evidenced by higher NOSE scores in postmenopausal women. Addressing nasal symptoms in postmenopausal women may improve their quality of life. Further research is needed to develop targeted interventions for managing nasal obstruction in this population.

The effects of mouth rinsing and gargling with mouthwash containing povidone-iodine and hydrogen peroxide on the cycle threshold value of Severe Acute Respiratory Syndrome Coronavirus 2: A randomized controlled trial of asymptomatic and mildly symptomatic patients

Background

Coronavirus disease 2019 can spread rapidly. Surgery in the oral cavity poses a high risk of transmission of severe acute respiratory syndrome coronavirus 2. The American Dental Association and the Centers for Disease Control and Prevention recommend the use of mouthwash containing 1.5% hydrogen peroxide (H 2O 2) or 0.2% povidone iodine (PI) to reduce the viral load in the upper respiratory tract and decrease the risk of transmission. The aim of the present study was to analyze the effect of mouth rinsing and gargling with mouthwash containing 1% PI, 0.5% PI, 3% H 2O 2, or 1.5% H 2O 2 and water on the cycle threshold (CT) value obtained by real-time reverse transcription polymerase chain reaction (RT-PCR).

Methods

This study is a randomized single blind controlled clinical trial which has been registered in the International Standard Randomized Controlled Trial Number (ISRCTN) registry on the 3 rd February 2022 (Registration number: ISRCTN18356379). In total, 69 subjects recruited from Persahabatan General Hospital who met the inclusion criteria were randomly assigned to one of four treatment groups or the control group. The subjects were instructed to gargle with 15 mL of mouthwash for 30 s in the oral cavity followed by 30 s in the back of the throat, three times per day for 5 days. CT values were collected on postprocedural days 1, 3, and 5.

Results

The results of the Friedman test significantly differed among the groups (n=15). The CT values increased from baseline (day 0) to postprocedural days 1, 3, and 5.

Conclusions

Mouth rinsing and gargling with mouthwash containing 1% PI, 0.5% PI, 3% H 2O 2, or 1.5% H 2O 2 and water increased the CT value.

A Comprehensive Literature Review on the Effects of Formaldehyde on the Upper Respiratory Tract

Prolonged exposure to indoor air pollutants at high concentrations can have adverse health effects on the respiratory system of individuals who spend most of their time indoors. Formaldehyde (FA) is a common indoor air pollutant because of its extensive use in household products such as cleaners, floorings, and furnishings. As a chemical, FA is highly water soluble and reactive. When its airborne form is inhaled, it is mainly absorbed in the upper airways. FA has been extensively studied for its carcinogenic effects, but it can also cause inflammation in the upper airways. The objective of the current review was to assess the secondary effects of such inflammation and how it can contribute to an increased risk for upper respiratory infections, which are mostly caused by viruses. A rigorous literature review was conducted through gathering, reading, and analyzing relevant literature, including peer-reviewed articles published after 1990 and seminal literature regardless of publication date. Findings from the review provide a greater understanding of the outcomes of FA exposure, the potential accumulative damage to the upper respiratory tract, and the associated increased risk for acute infections of the upper respiratory tract. This information can help in the development and enforcement of stricter regulations for furniture and building materials for household-related products to limit exposure to indoor pollutants such as FA.

Saline nasal irrigation and gargling in COVID-19: a multidisciplinary review of effects on viral load, mucosal dynamics, and patient outcomes

With unrelenting SARS-CoV-2 variants, additional COVID-19 mitigation strategies are needed. Oral and nasal saline irrigation (SI) is a traditional approach for respiratory infections/diseases. As a multidisciplinary network with expertise/experience with saline, we conducted a narrative review to examine mechanisms of action and clinical outcomes associated with nasal SI, gargling, spray, or nebulization in COVID-19. SI was found to reduce SARS-CoV-2 nasopharyngeal loads and hasten viral clearance. Other mechanisms may involve inhibition of viral replication, bioaerosol reduction, improved mucociliary clearance, modulation of ENaC, and neutrophil responses. Prophylaxis was documented adjunctive to personal protective equipment. COVID-19 patients experienced significant symptom relief, while overall data suggest lower hospitalization risk. We found no harm and hence recommend SI use, as safe, inexpensive, and easy-to-use hygiene measure, complementary to hand washing or mask-wearing. In view of mainly small studies, large well-controlled or surveillance studies can help to further validate the outcomes and to implement its use.

COVID-related mucormycosis mimicking dental infection

A recent increase in the prevalence of mucormycosis of the head and neck in patients who have recovered from COVID-19 following hospitalization has been reported. A Majority of the cases have been reported from India. Conditions such as diabetes mellitus, use of corticosteroids for other autoimmune conditions, organ transplant, immunosuppression, immunodeficiency, and malignancies especially hematologic ones, are all known risk factors for mucormycosis. Recently, hospitalization for COVID-19 has been added to the list of risk factors for opportunistic mucormycosis infection. This is likely attributable to the high doses and prolonged use of corticosteroids in the treatment of hospitalized COVID-19 patients. Case Description: Two patients with post-COVID-19 associated rhinocerebral mucormycosis presented with profound unexplained dental disease including tooth mobility and dental abscess mimicking periodontal disease. The patients were previously hospitalized for COVID-19 and received prolonged treatment with high doses of corticosteroids. The patients responded well to the surgical debridement with or without antifungal therapy. Conclusion: Oral healthcare providers including oral and maxillofacial surgeons, dentists, dental hygienists, and other dental practitioners can play a vital role in the recognition and early diagnosis of rhinocerebral mucormycosis given the large number of patients with severe COVID-19 infection who have recovered following hospitalization and/or received long-term high doses of immunosuppressive treatment.

Low dietary sodium potentially mediates COVID-19 prevention associated with whole-food plant-based diets

Compared with an omnivorous Western diet, plant-based diets containing mostly fruits, vegetables, grains, legumes, nuts and seeds, with restricted amounts of foods of animal origin, are associated with reduced risk and severity of COVID-19. Additionally, inflammatory immune responses and severe acute respiratory symptoms of COVID-19, including pulmonary oedema, shortness of breath, fever and nasopharyngeal infections, are associated with Na toxicity from excessive dietary Na. High dietary Na is also associated with increased risks of diseases and conditions that are co-morbid with COVID-19, including chronic kidney disease, hypertension, stroke, diabetes and obesity. This article presents evidence that low dietary Na potentially mediates the association of plant-based diets with COVID-19 prevention. Processed meats and poultry injected with sodium chloride contribute considerable amounts of dietary Na in the Western diet, and the avoidance or reduction of these and other processed foods in whole-food plant-based (WFPB) diets could help lower overall dietary Na intake. Moreover, high amounts of K in plant-based diets increase urinary Na excretion, and preagricultural diets high in plant-based foods were estimated to contain much lower ratios of dietary Na to K compared with modern diets. Further research should investigate low Na in WFPB diets for protection against COVID-19 and co-morbid conditions.

Biases in COVID-19 Case and Death Definitions: Potential Causes and Consequences

This paper investigates three controversies involving potential causes and consequences of information bias in case and death definitions during the coronavirus disease (COVID-19) pandemic. First, evidence suggests China's surveillance data were biased and misinterpreted by the World Health Organization (WHO), prompting the WHO to advise nations to copy China's lockdowns. China appeared to use narrow diagnostic definitions that undercounted cases and deaths. Second, novel genomic data disseminated during the pandemic without adequate guidance from rigorous epidemiologic studies biased infection control policies in many countries. A novel genomic sequence of a virus is insufficient to declare new cases of a novel disease. Third, media reports of COVID-19 surveillance data in many nations appeared to be biased. Broadened surveillance definitions captured additional information, but unadjusted surveillance data disseminated to the public are not true cases and deaths. Recommendations include clarification of the proper use of diagnostic and surveillance case and death definitions to avoid information bias.

Effects of Dietary Supplementation with Carrot-Derived Rhamnogalacturonan-I (cRG-I) on Accelerated Protective Immune Responses and Quality of Life in Healthy Volunteers Challenged with Rhinovirus in a Randomized Trial

An adequate and balanced supply of nutrients is essential for maintaining health, and an optimal immune response is fast, contained and properly controlled, curbing infections quickly while minimizing damage. Several micronutrients contribute to normal immune function and certain dietary fibers, for example pectic polysaccharides, can play an important role in educating and regulating immune cell responses. The aim of this paper is to elaborate on our initial findings that dietary supplementation with carrot-derived rhamnogalacturonan-I (cRG-I) accelerates and augments local innate immune and anti-viral interferon response to a rhinovirus-16 (RV16) infection and reduces the severity and duration of symptoms in humans. Dietary intake of cRG-I also enhanced immune responses to this respiratory viral infection as measured by ex vivo stimulation of whole blood with the Toll-like receptor 3 (TLR3) ligand polyinosinic:polycytidylic acid and NK cell function. Consumption of cRG-I also reduced the negative effects of this common cold infection on quality of life as assessed by individual symptom scores. RG-I from carrot is a safe, sustainable, and economically viable solution that could easily be integrated into food products and dietary supplements aiming to support immune fitness and wellbeing.

Antioxidants and clinical outcomes of patients with coronavirus disease 2019: A systematic review of observational and interventional studies

Coronavirus disease 2019 (COVID-19) is a newly emerging viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Oxidative stress appears to be a prominent contributor to the pathogenicity of SARS-CoV-2. Therefore, we carried out a systematic review of human observational and interventional studies to investigate the role of some antioxidants such as vitamins A, E, D, and C, selenium, zinc, and α-lipoic acid in the main clinical outcomes of subjects with COVID-19. Google Scholar, Cochrane Library, Web of Science, Scopus, and Medline were searched using Medical Subject Headings (MeSH) and non-MeSH terms without restrictions. Finally, 36 studies for vitamins C and D, selenium, and zinc were included in this systematic review; however, no eligible studies were found for vitamins A and E as well as α-lipoic acid. The results showed the promising role of vitamin C in inflammation, Horowitz index, and mortality; vitamin D in disease manifestations and severity, inflammatory markers, lung involvement, ventilation requirement, hospitalization, intensive care unit (ICU) admission, and mortality; selenium in cure rate and mortality; and zinc in ventilation requirement, hospitalization, ICU admission, biomarkers of inflammation and bacterial infection, and disease complications. In conclusion, it seems that antioxidants, especially vitamins C and D, selenium, and zinc, can improve multiple COVID-19 clinical outcomes. Nevertheless, more studies are necessary to affirm these results.

The residual effect of coronovirus disease 2019 on olfactory acuity and mucociliary clearance time: a cross-sectional, controlled study

Objective

This study evaluated the olfactory, sinonasal and mucociliary functions of patients with post-coronavirus disease 2019 long-term persistent olfactory dysfunction.

Method

Three groups of 30 patients each were formed: patients with a history of coronavirus disease 2019 infection with self-reported, persistent, sudden-onset olfactory dysfunction (group 1), patients with a history of coronavirus disease 2019 infection without any self-reported olfactory dysfunction (group 2) and healthy controls with no history of coronavirus disease 2019 infection (group 3). Saccharin time, Sniffin’ Sticks, Turkish Nasal Obstruction Symptom Evaluation and Sino-Nasal Outcome Test 22 scores were compared.

Results

Turkish Nasal Obstruction Symptom Evaluation scores were similar between groups (p = 0.252). Sino-Nasal Outcome Test-22 scores were higher in group 1 than groups 2 and 3 (p < 0.01 and p < 0.001, respectively). Saccharin time was significantly longer in group 1 than groups 2 and 3 (p < 0.05 and p < 0.01, respectively). Group 1 had lower olfactory scores than groups 2 and 3 (p < 0.001 and p < 0.001, respectively).

Conclusion

Mucociliary clearance time was significantly prolonged in patients with post-coronavirus disease 2019 persistent olfactory dysfunction. Coronavirus disease 2019 infection was likely to cause asymptomatic olfactory dysfunction.

COVID-19 Causes Ciliary Dysfunction as Demonstrated by Human Intranasal Micro-Optical Coherence Tomography Imaging

Severe acute respiratory syndrome coronavirus (SARS-CoV-2), causative agent of coronavirus disease 2019 (COVID-19), binds via ACE2 receptors, highly expressed in ciliated cells of the nasal epithelium. Micro-optical coherence tomography (μOCT) is a minimally invasive intranasal imaging technique that can determine cellular and functional dynamics of respiratory epithelia at 1-μm resolution, enabling real time visualization and quantification of epithelial anatomy, ciliary motion, and mucus transport. We hypothesized that respiratory epithelial cell dysfunction in COVID-19 will manifest as reduced ciliated cell function and mucociliary abnormalities, features readily visualized by μOCT. Symptomatic outpatients with SARS-CoV-2 aged ≥ 18 years were recruited within 14 days of symptom onset. Data was interpreted for subjects with COVID-19 (n=13) in comparison to healthy controls (n=8). Significant reduction in functional cilia, diminished ciliary beat frequency, and abnormal ciliary activity were evident. Other abnormalities included denuded epithelium, presence of mucus rafts, and increased inflammatory cells. Our results indicate that subjects with mild but symptomatic COVID-19 exhibit functional abnormalities of the respiratory mucosa underscoring the importance of mucociliary health in viral illness and disease transmission. Ciliary imaging enables investigation of early pathogenic mechanisms of COVID-19 and may be useful for evaluating disease progression and therapeutic response.

Graphical abstract

Influence of SARS-CoV-2 on airway mucus production: A review and proposed model

Coronavirus disease 2019 (COVID-19) is a worldwide pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has affected millions of lives. Individuals who survive severe COVID-19 can experience sustained respiratory symptoms that persist for months after initial infection. In other airway diseases, abnormal airway mucus contributes to sustained airway symptoms. However, the impact of SARS-CoV-2 on airway mucus has received limited attention. In the current review, we assess literature describing the impact of SARS-CoV-2 on airway pathophysiology with specific emphasis on mucus production. Accumulating evidence suggests that the 2 major secreted airway mucin glycoproteins, MUC5AC and MUC5B, are abnormal in some patients with COVID-19. Aberrations in MUC5AC or MUC5B in response to SARS-CoV-2 infection are likely due to inflammation, though the responsible mechanisms have yet to be determined. Thus, we also provide a proposed model highlighting mechanisms that can contribute to acute and sustained mucus abnormalities in SARS-CoV-2, with an emphasis on inflammatory cells and mediators, including mast cells and histamine. Last, we bring to light the challenges of studying abnormal mucus production in SARS-CoV-2 infections and discuss the strengths and limitations of model systems commonly used to study COVID-19. The evidence to date suggests that ferrets, nonhuman primates, and cats may have advantages over other models to investigate mucus in COVID-19.

Nasal Mucociliary Clearance and Sinonasal Symptoms in Healthcare Professionals Wearing FFP3 Respirators: A Prospective Cross-Sectional Study

Introduction

The purpose of the present study was to assess nasal mucociliary clearance (NMC) and sinonasal symptoms of healthcare professionals wearing filtering facepiece-3 (FFP3) respirators.

Methods

This prospective cross-sectional study was conducted at a large tertiary care academic center. Thirty-four healthcare professionals working at a coronavirus disease-19 patient care unit were included in the study. Visual analog scale (VAS) scores of sinonasal symptoms (nasal discharge, postnasal discharge, nasal blockage, hyposmia, facial pain/pressure, facial fullness, headache, fatigue, halitosis, cough) and the NMC times of the participants were assessed immediately before wearing FFP3 respirators and after 4 h of work with FFP3 respirators.

Results

The mean age of the participants was 28.82 ± 4.95 (range, 26–31) years. Twenty participants were female and 14 were male. After wearing the FFP3 respirators for 4 h, a statistically significant increase was observed in total VAS scores for all sinonasal symptoms and NMC times (p < 0.001). When the VAS score of each sinonasal symptom was evaluated separately, a statistically significant increase was found for VAS scores of nasal discharge, postnasal discharge, nasal blockage, hyposmia, facial pain/pressure, and facial fullness (p < 0.05).

Conclusion

The present study shows that nasal mucosal functions might be affected significantly after 4 h of using FFP3 respirators. The long-term effects and clinical significance of these short-term changes should be investigated on healthcare professionals in further studies.

The effect of COVID-19 on nasal mucociliary clearance

BACKGROUND

The impacts of coronavirus disease-2019 (COVID-19) on nasal mucociliary clearance (MCC) have shown conflicting results.

OBJECTIVES

The aim of this study was to determine whether COVID-19 infections affect nasal mucociliary activity using the saccharin test to measure nasal MCC time.

MATERIAL AND METHODS

This prospective comparative investigation included 25 patients with COVID-19 infection and 25 healthy controls. The nasal MCC time was assessed using the saccharin test. Saccharin test was applied to COVID-19 patients between the 10th and 20th days of COVID-19 test positivity. Patients admitted to the otolaryngology outpatient clinic with non-nasal symptoms and no history of COVID-19 infection served as the control subjects.

RESULTS

Age, gender distribution, smoking, and alcohol usage, and the existence of other systemic disorders had no statistically significant differences between the groups (p = 0.25, p = 0.77, p = 1.00, p = 0.28, p = 0.54, respectively). The COVID-19 group had a mean nasal MCC time of 12.00 ± 2.51 min, compared to 9.77 ± 2.51 min in the control group. The nasal MCC time in the COVID-19 group was statistically significantly longer (p = 0.043).

CONCLUSIONS AND SIGNIFICANCE

The COVID-19 infection negatively affects mucociliary activity and causes prolongation of MCC. As the nasal defense mechanism weakens in the early period after COVID-19 infection, susceptibility to respiratory infections may occur.

The relationship between Covid-19 and mucociliary clearance

BACKGROUND

The effect of Covid-19 infection on nasal mucociliary clearance (MCC) is unknown.

AIMS/OBJECTIVES

The aim of this study is to investigate the relationship between Covid-19 and nasal MCC in terms of smoking, Covid-19 symptoms and treatment.

METHODS

Thirty-six patients who were hospitalized in the pandemic ward due to Covid-19 and 36 volunteers (Covid-19 negative test result) who presented to the otolaryngology outpatient clinic with non-nasal symptoms were included in this study. The Saccharin test was performed in both groups to evaluate nasal MCC.

RESULTS

The patients and control groups were not significantly different in terms of age and gender. The nasal MCC time was significantly higher in the patient group compared to the control group (19.18 ± 10.84 min and 13.78 ± 8.18 min, p = .003).

CONCLUSIONS AND SIGNIFICANCE

In this study, we found that Covid-19 prolonged nasal MCC time regardless of age. We suggest that corticosteroids should be included in the treatment of Covid-19, both with its symptom reduction and its positive effect on MCC duration.

In Vitro Ciliotoxicity and Cytotoxicity Testing of Repeated Chronic Exposure to Topical Nasal Formulations for Safety Studies

Certain active drugs and excipients of nasal formulations may impair ciliary function and mucociliary clearance. The ciliary beat frequency (CBF) is a key parameter for determining mucociliary clearance rate, and in vitro assessments of CBF have proven to be accurate and reproducible. Since topical nasal formulations are applied with repeated doses, it is essential to elucidate their chronic, as opposed to acute, effect on mucociliary clearance and nasal mucosa. The aim of this study was to assess for the first time the ciliotoxicity and cytotoxicity of nasal sprays intended for chronic treatment (with repeated doses) using a previously designed set-up for CBF measurements. For 2 weeks, the 3D nasal MucilAir™ in vitro models were treated daily with undiluted or clinically relevant doses of mometasone nasal spray, placebo nasal spray, culture medium, or they were untreated. We demonstrated a dose-dependent and time-dependent (cumulative) effect of the nasal sprays on ciliary activity and cytotoxicity using CBF measurements and ultrastructural analysis, respectively. Our results indicate that repeated administration of clinically relevant doses of mometasone nasal spray is safe for in vivo use, which is in good agreement with a previous clinical study. Overall, our study suggests that such in vitro assays have great potential for topical nasal drug screening.

Current Understanding in the Pathophysiology of SARS-CoV-2-Associated Rhino-Orbito-Cerebral Mucormycosis: A Comprehensive Review

AIM

Recently, with the second wave of COVID-19, the Indian subcontinent has witnessed a dramatic rise in mucormycosis infection in patients recovered from COVID-19. This association has been documented in various case reports/case series and institutional experiences, and the mortality associated with this fungal infection is emerging as a cause of concern. The aim of the present paper is to provide a scientific overview on the pathogenesis of mucormycosis in COVID-19 beyond the conventional understanding of the disease process, which may not otherwise explain the increased incidence of mucormycosis in SARS-CoV-2.

METHODOLOGY

This paper is structured as a narrative review of the published literature on the pathogenesis of COVID-19 which contributes to the development of mucormycosis. Apart from the acknowledged role of ketoacidosis, high blood sugar, and iron metabolism in the pathogenesis of mucormycosis, other factors involved in pathophysiology of COVID-19 which might alter or enhance the mucormycosis infection such as (1) the role of ferritin, (2) high serum iron, (3) free radical-induced endothelitis, (4) hepcidin activation, (5) upregulation of glucose receptor protein (GRP78) are discussed in the pathophysiology of COVID-19-associated mucormycosis.

CONCLUSION

A new proposal for the pathogenesis based on the ferritin, viral mimicry of hepcidin and GRP78-CotH3 interaction, which clearly explains the surge in mucormycosis in SARS-CoV-2 infection, has been explained.

[Mucociliary clearance in COVID-19 - an underestimated danger area in early phase of disease?]

BACKGROUND

As with other inflammatory diseases, the (dry) cough in COVID-19 patients indicates that mucociliary clearance (MCC) is at least at risk, if not overloaded, damaged or largely inoperable. Coughing is an important secondary mechanism that only takes over bronchial cleansing as a replacement if the MCC has failed.

METHOD

The review article describes the physiology and pathophysiology of MCC and its possible role in the pathogenesis of COVID-19.

RESULTS AND CONCLUSIONS

Human and animal studies as well as autopsy reports indicate that MCC could also be important for the COVID-19 pathogenesis. In primary care, MCC plays a major role in inflammatory respiratory diseases. In Germany, drugs for self-medication are approved for treatment and, due to the high quality of studies, are also recommended in the respective guidelines. A symptomatic approach to stabilize the airway barrier would also be conceivable in the early outpatient phase of COVID-19.

Is loss of smell an early predictor of COVID-19 severity: a systematic review and meta-analysis

Anecdotal evidence suggests that the severity of coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is likely to be distinguished by variations in loss of smell (LOS). Thus, we conducted a meta-analysis of 45 articles that include a total of 42,120 COVID-19 patients from 17 different countries to demonstrate that severely ill or hospitalized COVID-19 patients have a lesser chance of experiencing LOS than non-severely ill or non-hospitalized COVID-19 patients (odds ratio = 0.527 [95% CI 0.373–0.744; p < 0.001] and 0.283 [95% CI 0.173–0.462; p < 0.001], respectively). We also proposed a possible mechanism underlying the association of COVID-19 severity with anosmia, which may explain why patients without sense of smell develop severe COVID-19. Variations in LOS according to the severity of COVID-19 is a global phenomenon, with few exceptions. Since severely ill patients have a lower rate of anosmia, patients without anosmia should be monitored more closely in the early stages of COVID-19, for early diagnosis of severity of illness. An understanding of how the severity of COVID-19 infection and LOS are associated has profound implications for the clinical management and mitigation strategies for the disease.

Sodium Toxicity in the Nutritional Epidemiology and Nutritional Immunology of COVID-19

Dietary factors in the etiology of COVID-19 are understudied. High dietary sodium intake leading to sodium toxicity is associated with comorbid conditions of COVID-19 such as hypertension, kidney disease, stroke, pneumonia, obesity, diabetes, hepatic disease, cardiac arrhythmias, thrombosis, migraine, tinnitus, Bell's palsy, multiple sclerosis, systemic sclerosis, and polycystic ovary syndrome. This article synthesizes evidence from epidemiology, pathophysiology, immunology, and virology literature linking sodium toxicological mechanisms to COVID-19 and SARS-CoV-2 infection. Sodium toxicity is a modifiable disease determinant that impairs the mucociliary clearance of virion aggregates in nasal sinuses of the mucosal immune system, which may lead to SARS-CoV-2 infection and viral sepsis. In addition, sodium toxicity causes pulmonary edema associated with severe acute respiratory syndrome, as well as inflammatory immune responses and other symptoms of COVID-19 such as fever and nasal sinus congestion. Consequently, sodium toxicity potentially mediates the association of COVID-19 pathophysiology with SARS-CoV-2 infection. Sodium dietary intake also increases in the winter, when sodium losses through sweating are reduced, correlating with influenza-like illness outbreaks. Increased SARS-CoV-2 infections in lower socioeconomic classes and among people in government institutions are linked to the consumption of foods highly processed with sodium. Interventions to reduce COVID-19 morbidity and mortality through reduced-sodium diets should be explored further.

Compartmental Model Suggests Importance of Innate Immune Response to COVID-19 Infection in Rhesus Macaques

The pandemic outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has quickly spread worldwide, creating a serious health crisis. The virus is primarily associated with flu-like symptoms but can also lead to severe pathologies and death. We here present an ordinary differential equation model of the intrahost immune response to SARS-CoV-2 infection, fitted to experimental data gleaned from rhesus macaques. The model is calibrated to data from a nonlethal infection, but the model can replicate behavior from various lethal scenarios as well. We evaluate the sensitivity of the model to biologically relevant parameters governing the strength and efficacy of the immune response. We also simulate the effect of both anti-inflammatory and antiviral drugs on the host immune response and demonstrate the ability of the model to lessen the severity of a formerly lethal infection with the addition of the appropriately calibrated drug. Our model emphasizes the importance of tight control of the innate immune response for host survival and viral clearance.

The effect of N95 and surgical masks on mucociliary clearance function and sinonasal complaints

PURPOSE

The aim of this study was to reveal the effect of N95 and surgical masks on mucociliary clearance function and sinonasal complaints.

METHODS

Sixty participants were enrolled in this study, including 30 people in N95 mask group and 30 people in surgical mask group. Two interviews, three days apart, were performed with all participants. The participants were asked not to use any mask before the first interview while they were asked to use the determined mask just before the second interview for 8 h. In both interviews, the mucociliary clearance times (MCTs) were measured and participants were asked to score ten distinct sinonasal complaints using visual analog scale (VAS). Data obtained from first interview were named pre-mask data, data obtained from second interview were called after-mask data. In both groups, pre-mask MCTs and VAS scores were compared with after-mask MCTs and VAS scores.

RESULTS

After-mask MCTs (mean = 13.03 ± 6.05 min) were significantly longer than pre-mask MCTs (mean = 10.19 ± 4.21 min) in N95 mask group (p = 0.002). No significant difference was found between after-mask and pre-mask MCTs (mean = 12.05 ± 5.21 min, mean = 11.00 ± 5.44 min, respectively) in surgical mask group (p = 0.234). When after-mask VAS scores were compared with pre-mask VAS scores, it was found that N95 mask use increased nasal blockage and postnasal discharge, surgical mask usage increased nasal blockage.

CONCLUSION

While the use of N95 mask leads to nasal blockage and postnasal discharge, surgical mask use results in nasal blockage. N95 masks cause impairment in mucociliary clearance function. But all these effects are mild. Surgical masks have not been found to have any effect on mucociliary clearance function.

Potential Applications of Conducting Polymers to Reduce Secondary Bacterial Infections among COVID-19 Patients: a Review

The COVID-19 pandemic is a motivation for material scientists to search for functional materials with valuable properties to alleviate the risks associated with the coronavirus. The formulation of functional materials requires synergistic understanding on the properties of materials and mechanisms of virus transmission and disease progression, including secondary bacterial infections that are prevalent in COVID-19 patients. A viable candidate in the struggle against the pandemic is antimicrobial polymer, due to their favorable properties of flexibility, lightweight, and ease of synthesis. Polymers are the base material for personal protective equipment (PPE), such as gloves, face mask, face shield, and coverall suit for frontliners. Conducting polymers (CPs) are polymers with electrical properties due to the addition of dopant in the polymer structure. The conductivity of polymers augments their antiviral and antibacterial properties. This review discusses the types of CPs and how their properties could be exploited to ward off bacterial infections in hospital settings, specifically in cases involving COVID-19 patients. This review also covers common CPs fabrication techniques. The key components to produce CPs at several possibilities to fit the current needs in fighting secondary bacterial infections are also discussed.