Immunological status of the olfactory bulb in a murine model of Toll-like receptor 3-mediated upper respiratory tract inflammation

Background Postviral olfactory dysfunction (PVOD) following a viral upper respiratory tract infection (URI) is one of the most common causes of olfactory disorders, often lasting for over a year. To date, the molecular pathology of PVOD has not been elucidated. Methods A murine model of Toll-like receptor 3 (TLR3)-mediated upper respiratory tract inflammation was used to investigate the impact of URIs on the olfactory system. Inflammation was induced via the intranasal administration of polyinosinic–polycytidylic acid (poly(I:C), a TLR3 ligand) to the right nostril for 3 days. Peripheral olfactory sensory neurons (OSNs), immune cells in the olfactory mucosa, and glial cells in the olfactory bulb (OB) were analyzed histologically. Proinflammatory cytokines in the nasal tissue and OB were evaluated using the quantitative real-time polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA). Results In the treated mice, OSNs were markedly reduced in the olfactory mucosa, and T cell and neutrophil infiltration therein was observed 1 day after the end of poly(I:C) administration. Moreover, there was a considerable increase in microglial cells and slight increase in activated astrocytes in the OB. In addition, qPCR and ELISA revealed the elevated expression of interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, and interferon-gamma both in the OB and nasal tissue. Conclusions Taken together, the decreased peripheral OSNs, OB microgliosis, and elevated proinflammatory cytokines suggest that immunological changes in the OB may be involved in the pathogenesis of PVOD.

Mucormycosis in Post COVID-19 Patients: A Case Study

Introduction: Acute respiratory distress syndrome (ARDS) is a common complication of severe pneumonia virus, such as the flu and COVID-19, which requires critical treatment, including asthma support, corticosteroids, and other treatments to prevent acute respiratory tract inflammation. Although steroid treatment is limited to the treatment of viral pneumonia, it is usually a double-edged sword, leading to increased morbidity and mortality. Mucormycosis is a fungal emergency with a high tendency for contaguous spread and a poor prognosis if not detected and treated promptly. Mucormycosis is believed to be caused by uncontrolled diabetes mellitus (DM) and other immunosuppressive disorders, such as corticosteroid therapy. Aim: To discuss causality factor of mucormycosis in COVID-19 infection. Conclusion: COVID-19 is correlated with a high rate of secondary infections, both bacterial and fungal, most likely as a result of immune dysregulation. Furthermore, the widespread use of steroids and broad-spectrum antibiotics as part of the COVID-19 remedy can result in the production or exacerbation of pre-existing fungal diseases. Physicians should be mindful of the likelihood of invasive secondary fungal infections in patients with COVID-19 infection, especially in those that have pre-existing risk factors, and should be able to detect and treat these infections early in order to reducing mortality and morbidity.

Hamster models of COVID-19 pneumonia reviewed: How human can they be?

The dramatic global consequences of the coronavirus disease 2019 (COVID-19) pandemic soon fueled quests for a suitable model that would facilitate the development and testing of therapies and vaccines. In contrast to other rodents, hamsters are naturally susceptible to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the Syrian hamster ( Mesocricetus auratus) rapidly developed into a popular model. It recapitulates many characteristic features as seen in patients with a moderate, self-limiting course of the disease such as specific patterns of respiratory tract inflammation, vascular endothelialitis, and age dependence. Among 4 other hamster species examined, the Roborovski dwarf hamster ( Phodopus roborovskii) more closely mimics the disease in highly susceptible patients with frequent lethal outcome, including devastating diffuse alveolar damage and coagulopathy. Thus, different hamster species are available to mimic different courses of the wide spectrum of COVID-19 manifestations in humans. On the other hand, fewer diagnostic tools and information on immune functions and molecular pathways are available than in mice, which limits mechanistic studies and inference to humans in several aspects. Still, under pandemic conditions with high pressure on progress in both basic and clinically oriented research, the Syrian hamster has turned into the leading non-transgenic model at an unprecedented pace, currently used in innumerable studies that all aim to combat the impact of the virus with its new variants of concern. As in other models, its strength rests upon a solid understanding of its similarities to and differences from the human disease, which we review here.

Low Molecular Weight Heparin Improves the Inflammatory State of Acute Sinusitis Rats Through Inhibiting the TLR4-MyD88-NF-κB Signaling Pathway

Introduction: Low molecular weight heparin (LMWH), a natural sulfated glycosaminoglycan with an affinity for proangiogenic factors, is produced by chemical or enzymatic depolymerization of unfractionated heparin (UFH). Known for its anticoagulant effects, LMWH has recently been reported to have a strong anti-inflammatory effect on colitis, myocarditis, and airway inflammation. However, as a newly-developed drug, its anti-inflammatory mechanism in upper respiratory tract inflammation has not been well-studied.Methods: SD rats were randomly divided into control and experimental groups. The experimental group was established by building an acute nasal sinusitis model with expansion sponges mixed with Streptococcus pneumoniae. Then the experimental group rats were subcutaneously injected with different concentrations of LMWH. After seven consecutive days of injection, some rats were sacrificed, and blood and nasal mucosa samples were taken to determine their inflammation status. The remaining acute sinusitis rats were randomly selected for a week of nasal irrigation with normal saline or saline mixed with different concentrations of LMWH. One week later, rats were sacrificed, and samples of blood and nasal mucosa were taken to determine the inflammation status.Results: Rat nasal mucosa in the model group had obvious inflammation. The degree of nasal mucosa inflammation damage in the experimental group was lower than in the experimental control group, proving that LMWH has a protective effect on the nasal mucosa and that the effect correlates with dosage. Irrigation of the nose with saline mixed with LMWH can improve the anti-inflammatory effect. Protein related to the TLR4-MyD88-NF-κB signaling pathway was activated in the acute sinusitis rat model, and LMWH can significantly inhibit its expression.Conclusion: This is the first report of the anti-inflammatory effect of LMWH in acute upper respiratory tract inflammation, together with an explanation of its anti-inflammatory mechanism. The findings contribute a theoretical basis for its potential anti-tumor effect.

Recent Findings on Cell-Based Therapies for COVID19-Related Pulmonary Fibrosis

COVID-19 has spread worldwide, including the United States, United Kingdom, and Italy, along with its site of origin in China, since 2020. The virus was first found in the Wuhan seafood market at the end of 2019, with a controversial source. The clinical symptoms of COVID-19 include fever, cough, and respiratory tract inflammation, with some severe patients developing an acute and chronic lung injury, such as acute respiratory distress syndrome (ARDS) and pulmonary fibrosis (PF). It has already claimed approximately 300 thousand human lives and the number is still on the rise; the only way to prevent the infection is to be safe till vaccines and reliable treatments develop. In previous studies, the use of mesenchymal stem cells (MSCs) in clinical trials had been proven to be effective in immune modulation and tissue repair promotion; however, their efficacy in treating COVID-19 remains underestimated. Here, we report the findings from past experiences of SARS and MSCs, and how SARS could also induce PF. Such studies may help to understand the rationale for the recent cell-based therapies for COVID-19.

Comment on “The importance of physical exercise during the coronavirus (COVID-19) pandemic”

SUMMARY Currently, many people have been infected by the Coronavirus disease (COVID-19) and presented cardiorespiratory symptoms caused mainly by the host immune system response and respiratory tract inflammation. So far, there is no effective treatment to fight off COVID-19 and, despite many daily speculations about new treatments and vaccines, in this article, we discuss the effectiveness of a cheap and scientific proven technique to treat and prevent several diseases. Many studies have shown the benefits of physical exercise in individuals who have practiced it routinely. This approach is a great strategy to improve people's cardiorespiratory capacity, inflammation system, and immune response. Due to the quarantine period, the practice of physical exercise at home can also be used to fight off COVID-19 and must be inserted into people's routines.

The next-generation combination drugs as part of the comprehensive therapy for inflammatory diseases of the pharynx

Inflammatory diseases of the pharynx constitute one of the most significant nosologies groups in the ENT organ diseases profile. According to modern epidemiological data, acute and chronic tonsillopharyngitis are inferior only to influenza and other forms of ARVI with predominantly nasal and paranasal sinuses, as well as the lower respiratory tract inflammation in prevalence among the population. Infectious pathogens are the most common etiology of inflammatory diseases of the pharynx. Accordingly, the pharmacological agents should be selected among the drugs having pronounced antimicrobial activity against both bacterial and other organisms - viral and fungal, and an analgesic effect, as sore throat is the main symptom of tonsillofingitis. The combination preparation Septolete® total is one of such drugs.