Pulmonary pathology of ARDS in COVID-19: A pathological review for clinicians

Recent advances in TGF-β signaling pathway in COVID-19 pathogenesis: A review

The coronavirus disease 2019 (COVID-19) has resulted in approximately 7.0 million fatalities between 2019 and 2022, underscoring a pressing need for comprehensive research into its underlying mechanisms and therapeutic avenues. A distinctive feature of severe COVID-19 is the dysregulated immune response characterized by excessive activation of immune cells and the consequent cytokine storms. Recent advancements in our understanding of cellular signaling pathways have illuminated the role of Transforming Growth Factor Beta (TGF-β) as a pivotal signaling molecule with significant implications for the pathogenesis of infectious diseases, including COVID-19. Emerging evidence reveals that TGF-β signaling, when activated by viral components or secondary pathways, adversely affects diverse cell types, particularly immune cells, and lung tissue, leading to complications such as pulmonary fibrosis. In our review article, we critically evaluate recent literature on the involvement of TGF-β signaling in the progression of COVID-19. We discuss a range of pharmacological interventions, including nintedanib, pirfenidone, corticosteroids, proton pump inhibitors, and histone deacetylase inhibitors, and their potential to modulate the TGF-β pathway in the context of COVID-19 treatment. Additionally, we explore ongoing clinical trials involving mesenchymal stem cells, low-dose radiation therapy, and artemisinin derivatives to assess their impact on TGF-β levels and subsequent clinical outcomes in COVID-19 patients. This review is particularly relevant at this juncture as the global health community continues to grapple with the ramifications of the COVID-19 pandemic, highlighting the urgent need for targeted therapeutic strategies aimed at TGF-β modulation to mitigate disease severity and improve patient outcomes.

Machine Learning identifies remodeling patterns in human lung extracellular matrix

Organ function depends on the three-dimensional integrity of the extracellular matrix (ECM). The structure resulting from the location and association of ECM components is a central regulator of cell behavior, but a dearth of matrix-specific analysis keeps it unresolved. Here, we deploy a high-resolution, 3D ECM mapping method and design a machine-learning powered pipeline to detect and characterize ECM architecture during health and disease. We deploy these tools in the human lung, an organ heavily dependent on ECM structure that can host diseases with different histopathologies. We analyzed segments from healthy, emphysema, usual interstitial pneumonia, sarcoidosis, and COVID-19 patients, and produced a remodeling signature per disease and a health/disease probability map from which we inferred the architecture of healthy and diseased ECM. Our methods demonstrate that exaggerated matrix deposition, or fibrosis, is not a single phenomenon, but a series of disease-specific alterations. STATEMENT OF SIGNIFICANCE: : The extracellular matrix, or ECM, is the foremost biomaterial. It shapes and supports all tissues while regulating all cells. ECM structure is intricate, yet precise: each organ, at every stage, has a specific ECM structure. During disease, tissues suffer from structural changes that accelerate and perpetuate illness by dysregulating cells. Both healthy and diseased ECM structures are of great biomedical importance, but surprisingly, they have not been mapped in detail. Here, we present a method that combines tissue engineering with machine learning to reveal, map and analyze ECM structures, applied it to pulmonary diseases that kill millions every year. This method can bring objectivity and a higher degree of confidence into the diagnosis of pulmonary disease. In addition the amount of tissue needed for a firm diagnosis may be much smaller than required for manual microscopy evaluation.

Nebulized alteplase in coronavirus disease 2019 pneumonia: a case series

BACKGROUND

Many patients with severe coronavirus disease 2019 pneumonia exhibit signs of microthrombosis. Previous studies discussed intravenous fibrinolytic agents as potential add-on therapy in these patients. Therefore, we propose the inhalative administration of fibrinolytics as a possible safer alternative.

CASE PRESENTATION

This case series describes five white male patients, aged 51-78 years, treated with off-label inhalation of alteplase between November and December 2020. All patients suffered from severe severe acute respiratory syndrome coronavirus 2 infection with respiratory failure. Pulmonary embolism was ruled out by pulmonary angiogram in computed tomography scans, and all patients showed signs of coronavirus disease 2019 pneumonia. Four patients improved clinically, while one patient with advanced chronic diseases died due to multiple organ failure. No directly associated adverse effects were observed following inhalation of alteplase.

CONCLUSION

This case series warrants further attention to investigate inhalative alteplase as an additional treatment in patients with severe coronavirus disease 2019 infection.

Animal models of infection-induced acute lung injury

Aim: Acute lung injury (ALI) is characterized by severe hypoxemia, reduced lung elasticity, and notable pulmonary edema, often caused by infections and potentially progressing to ARDS. This article explores animal models of ALI and clarifies its main pathogenic mechanisms.

Materials and Methods: we reviewed 20 years of ALI animal model advancements via PubMed, assessing clinical symptoms, histopathology, and reproducibility, and provided guidance on selecting models aligned with ALI pathogenesis.

Results: key proinflammatory mediators and interleukins play a significant role in ALI development, though their interactions are not fully understood. Preclinical models are essential for investigating ALI causes and testing treatments. Animal models mimic ALI from sources such as infections, drugs, and I/R events, but differences between mouse and human lungs necessitate careful validation of these findings.

Conclusions: A comprehensive strategy is essential to address clinical treatment and drug R&D challenges to prevent severe complications and reduce mortality rates.

Atractylodin modulates ASAH3L to improve galactose metabolism and inflammation to alleviate acute lung injury

Acute lung injury (ALI) is a lung disease characterized by an excessive inflammatory response and damage to lung epithelial cells. Atractylodin (ATL) has good anti-inflammatory activity and protects the integrity of the epithelial cell barrier. However, the efficacy of ATL in the treatment of ALI and its mechanism is unclear. We investigated the efficacy of ATL in treating ALI and explored its targets and mechanisms. The results showed that ATL significantly reduced the wet-dry ratio of lungs of rats with ALI, improved the pathological changes, and lowered the expression of the inflammatory factors. Combined metabolomic and transcriptomic analyses showed that ATL can reduce inflammation by inhibiting and activating the HIF-1 signaling pathway and modulating ASAH3L to improve galactose metabolism, thereby alleviating ALI. In conclusion, ATL may be a potential drug for the treatment of acute lung injury.

COVID-19: a multi-organ perspective

In this mini review, we explore the complex network of inflammatory reactions incited by SARS-CoV-2 infection, which extends its reach well beyond the respiratory domain to influence various organ systems. Synthesizing existing literature, it elucidates how the hyperinflammation observed in COVID-19 patients affects multiple organ systems leading to physiological impairments that can persist over long after the resolution of infection. By exploring the systemic manifestations of this inflammatory cascade, from acute respiratory distress syndrome (ARDS) to renal impairment and neurological sequelae, the review highlights the profound interplay between inflammation and organ dysfunction. By synthesizing recent research and clinical observations, this mini review aims to provide an overview of the systemic interactions and complications associated with COVID-19, underscoring the need for an integrated approach to treatment and management. Understanding these systemic effects is crucial for improving patient outcomes and preparing for future public health challenges.

Revisiting the dimensions of universal vaccine with special focus on COVID-19: Efficacy versus methods of designing

Even though the use of SARS-CoV-2 vaccines during the COVID-19 pandemic showed unprecedented success in a short time, it also exposed a flaw in the current vaccine design strategy to offer broad protection against emerging variants of concern. However, developing broad-spectrum vaccines is still a challenge for immunologists. The development of universal vaccines against emerging pathogens and their variants appears to be a practical solution to mitigate the economic and physical effects of the pandemic on society. Very few reports are available to explain the basic concept of universal vaccine design and development. This review provides an overview of the innate and adaptive immune responses generated against vaccination and essential insight into immune mechanisms helpful in designing universal vaccines targeting influenza viruses and coronaviruses. In addition, the characteristics, safety, and factors affecting the efficacy of universal vaccines have been discussed. Furthermore, several advancements in methods worthy of designing universal vaccines are described, including chimeric immunogens, heterologous prime-boost vaccines, reverse vaccinology, structure-based antigen design, pan-reactive antibody vaccines, conserved neutralizing epitope-based vaccines, mosaic nanoparticle-based vaccines, etc. In addition to the several advantages, significant potential constraints, such as defocusing the immune response and subdominance, are also discussed.

Ferroptosis: a potential target for acute lung injury

Acute lung injury (ALI) is caused by a variety of intrapulmonary and extrapulmonary factors and is associated with high morbidity and mortality. Oxidative stress is an important part of the pathological mechanism of ALI. Ferroptosis is a mode of programmed cell death distinguished from others and characterized by iron-dependent lipid peroxidation. This article reviews the metabolic regulation of ferroptosis, its role in the pathogenesis of ALI, and the use of ferroptosis as a therapeutic target regarding the pharmacological treatment of ALI.

The influence of COVID-19 on short-term mortality in acute ischemic stroke: A systematic review and meta-analysis

OBJECTIVE

To evaluate the differences in short-term mortality risk between acute ischemic stroke (AIS) patients with and without SARS-CoV-2 infection.

METHODS

PubMed, EMBASE, Scopus, and Cochrane Databases were systematically searched from December 1, 2019 to May 20, 2022 using the keywords coronavirus disease 2019 (COVID-19), COVID-19, SARS-CoV-2, and ischemic stroke. A random-effects model was estimated, and subgroup analysis and meta-regressions were performed. The quality of eligible studies was assessed using the Newcastle-Ottawa Scale.

RESULTS

A total of 26 eligible studies with 307,800 patients were included in this meta-analysis. The overall results show that in-hospital and 90-day mortality was 3.31-fold higher in AIS with SARS-CoV-2 patients compared with those without SARS-CoV-2. When matched for age and National Institutes of Health Stroke Scale score at admission, the risk ratio of in-hospital mortality from AIS among patients with SARS-CoV-2 versus without decreased to 2.83. Reperfusion therapy and endovascular thrombectomy may further reduce the risk of death in patients to some extent but do not increase the incidence of symptomatic intracerebral hemorrhage. Meta-regression showed that in-hospital mortality decreased with increasing National Institutes of Health Stroke Scale score in AIS with SARS-CoV-2 compared to those without SARS-CoV-2 and that the difference in mortality risk between the 2 was independent of age and sex.

CONCLUSIONS

The results of this study suggest that AIS patients with SARS-CoV-2 have higher short-term mortality compared to AIS patients without SARS-CoV-2, and reperfusion and endovascular thrombectomy therapy may reduce the risk of short-term mortality to some extent. The differences in in-hospital mortality risk were similar across ages and sexes. Focused attention is therefore needed on AIS patients with SARS-CoV-2 to control mortality.

Impact of Omega-3 Fatty Acid Supplementation in Parenteral Nutrition on Inflammatory Markers and Clinical Outcomes in Critically Ill COVID-19 Patients: A Randomized Controlled Trial

The heightened inflammatory response observed in COVID-19 patients suggests that omega-3 fatty acids (O3FA) may confer anti-inflammatory benefits. This randomized, double-blind, single-center clinical trial aimed to evaluate the effect of O3FA supplementation in parenteral nutrition (PN) on inflammatory markers in COVID-19 patients admitted to the intensive care unit (ICU). A total of 69 patients were randomized into three groups: one received standard lipid emulsion, and two received O3FA (Omegaven®) at doses of 0.1 g/kg/day and 0.2 g/kg/day, respectively, in addition to Smoflipid®. The primary outcomes measured were serum levels of C-reactive protein (CRP) and interleukin-6 (IL-6) on days 1, 5, and 10 of PN initiation. Secondary outcomes included additional inflammatory markers (TNF-α, IFN-γ, IL-1Ra, CXCL10), hepatic function, triglyceride levels, and clinical outcomes such as mortality and length of ICU and hospital stay. Results indicated a significant reduction in CRP, IL-6, and CXCL10 levels in the group receiving 0.1 g/kg/day O3FA compared to the control. Additionally, the higher O3FA dose was associated with a shorter ICU and hospital stay. These findings suggest that O3FA supplementation in PN may reduce inflammation and improve clinical outcomes in critically ill COVID-19 patients.

Survival analysis of COVID-19 versus non-COVID-19 patients requiring intensive care for acute respiratory distress syndrome: An observational retrospective study

Background/Aim

This study analyzed clinical factors impacting the survival of COVID-19 patients with acute respiratory distress síndrome, or ARDS (CARDS) to ICU compared to non-COVID-19 ARDS patients.

Methods

Clinical variables from 1,008 CARDS cases and 332 ARDS cases were computed using learning algorithms. The multivariable Cox proportional hazards regression models with the enter method evaluated risk factors and ICU mortality relationships. The survival analysis was completed with Kaplan-Meier and the log-rank tests.

Results

A Random Forest model revealed that mechanical ventilation-related factors, oxygenation, blood pH, superinfection, shock, and ICU length of stay have the greatest effects on ICU survival. According to a multivariate Cox model, reintubation and a high-flow nasal cannula were essential for survival in CARDS patients during the ICU stay. The length of stay in the ICU diminishes in patients older than 45 years, regardless of the source of ARDS.

Conclusion

This study gives recommendations for the respiratory care of ARDS in COVID-19 patients.

Severe COVID-19 infection: An institutional review and literature overview

BACKGROUND

Our study aimed to describe the group of severe COVID-19 patients at an institutional level, and determine factors associated with different outcomes.

METHODS

A retrospective chart review of patients admitted with severe acute hypoxic respiratory failure due to COVID-19 infection. Based on outcomes, we categorized 3 groups of severe COVID-19: (1) Favorable outcome: progressive care unit admission and discharge (2) Intermediate outcome: ICU care (3) Poor outcome: in-hospital mortality.

RESULTS

Eighty-nine patients met our inclusion criteria; 42.7% were female. The average age was 59.7 (standard deviation (SD):13.7). Most of the population were Caucasian (95.5%) and non-Hispanic (91.0%). Age, sex, race, and ethnicity were similar between outcome groups. Medicare and Medicaid patients accounted for 62.9%. The average BMI was 33.5 (SD:8.2). Moderate comorbidity was observed, with an average Charlson Comorbidity index (CCI) of 3.8 (SD:2.6). There were no differences in the average CCI between groups(p = 0.291). Many patients (67.4%) had hypertension, diabetes (42.7%) and chronic lung disease (32.6%). A statistical difference was found when chronic lung disease was evaluated; p = 0.002. The prevalence of chronic lung disease was 19.6%, 27.8%, and 40% in the favorable, intermediate, and poor outcome groups, respectively. Smoking history was associated with poor outcomes (p = 0.04). Only 7.9% were fully vaccinated. Almost half (46.1%) were intubated and mechanically ventilated. Patients spent an average of 12.1 days ventilated (SD:8.5), with an average of 6.0 days from admission to ventilation (SD:5.1). The intermediate group had a shorter average interval from admission to ventilator (77.2 hours, SD:67.6), than the poor group (212.8 hours, SD:126.8); (p = 0.001). The presence of bacterial pneumonia was greatest in the intermediate group (72.2%), compared to the favorable group (17.4%), and the poor group (56%); this was significant (p<0.0001). In-hospital mortality was seen in 28.1%.

CONCLUSION

Most patients were male, obese, had moderate-level comorbidity, a history of tobacco abuse, and government-funded insurance. Nearly 50% required mechanical ventilation, and about 28% died during hospitalization. Bacterial pneumonia was most prevalent in intubated groups. Patients who were intubated with a good outcome were intubated earlier during their hospital course, with an average difference of 135.6 hours. A history of cigarette smoking and chronic lung disease were associated with poor outcomes.

Therapeutic effects of high-dose vitamin C supplementation in patients with COVID-19: a meta-analysis

CONTEXT

Coronavirus disease 2019 (COVID-19) could induce the "cytokine storm" due to overactivation of immune system and accompanied by acute respiratory distress syndrome as a serious complication. Vitamin C has been effective in improving lung function of patients by reducing inflammation.

OBJECTIVE

The aim was to explore the therapeutic effects of high-dose vitamin C supplementation for patients with COVID-19 using meta-analysis.

DATA SOURCES

Published studies were searched from PubMed, Cochrane Library, Web of Science, EMBASE, and China National Knowledge Infrastructure databases up to August 2022 using the terms "vitamin C" and "COVID-19". Data analyses were performed independently by 2 researchers using the PRISMA guidelines.

DATA EXTRACTION

Heterogeneity between the included studies was assessed using I2 statistics. When I2 ≥50%, the random-effects model was used; otherwise, a fixed-effects model was applied. Stata 14.0 software was used to pool data by standardized mean differences (SMDs) with 95% CIs or odds ratios (ORs) with 95% CIs.

DATA ANALYSIS

The 14 studies had a total of 751 patients and 1583 control participants in 7 randomized controlled trials and 7 retrospective studies. The vitamin C supplement significantly increased ferritin (SMD = 0.272; 95% CI: 0.059 to 0.485; P = 0.012) and lymphocyte count levels (SMD = 0.376; 95% CI: 0.153 to 0.599; P = 0.001) in patients with COVID-19. Patients administered vitamin C in the length of intensive care unit staying (SMD = 0.226; 95% CI: 0.073 to 0.379; P = 0.004). Intake of vitamin C prominently alleviate disease aggravation (OR = 0.344, 95%CI: 0.135 to 0.873, P = 0.025).

CONCLUSIONS

High-dose vitamin C supplementation can alleviate inflammatory response and hinder the aggravation of COVID-19.

Role of biomarkers and molecular signaling pathways in acute lung injury

BACKGROUND

Acute lung injury (ALI) is caused by bacterial, fungal, and viral infections. When pathogens invade the lungs, the immune system responds by producing cytokines, chemokines, and interferons to promote the infiltration of phagocytic cells, which are essential for pathogen clearance. Their excess production causes an overactive immune response and a pathological hyper-inflammatory state, which leads to ALI. Until now, there is no particular pharmaceutical treatment available for ALI despite known inflammatory mediators like neutrophil extracellular traps (NETs) and reactive oxygen species (ROS).

OBJECTIVES

Therefore, the primary objective of this review is to provide the clear overview on the mechanisms controlling NETs, ROS formation, and other relevant processes during the pathogenesis of ALI. In addition, we have discussed the significance of epithelial and endothelial damage indicators and several molecular signaling pathways associated with ALI.

METHODS

The literature review was done from Web of Science, Scopus, PubMed, and Google Scholar for ALI, NETs, ROS, inflammation, biomarkers, Toll- and nucleotide-binding oligomerization domain (NOD)-like receptors, alveolar damage, pro-inflammatory cytokines, and epithelial/endothelial damage alone or in combination.

RESULTS

This review summarized the main clinical signs of ALI, including the regulation and distinct function of epithelial and endothelial biomarkers, NETs, ROS, and pattern recognition receptors (PRRs).

CONCLUSION

However, no particular drugs including vaccine for ALI has been established. Furthermore, there is a lack of validated diagnostic tools and a poor predictive rationality of current therapeutic biomarkers. Hence, extensive and precise research is required to speed up the process of drug testing and development by the application of artificial intelligence technologies, structure-based drug design, in-silico approaches, and drug repurposing.

A New Methodology for the Oxygen Measurement in Lung Tissue of an Aged Ferret Model Proves Hypoxia during COVID-19

Oxygen as a key element has a high impact on cellular processes. Infection with a pathogen such as SARS-CoV-2 and after inflammation may lead to hypoxic conditions in tissue that impact cellular responses. To develop optimized translational in vitro models for a better understanding of physiologic and pathophysiologic oxygen conditions, it is a prerequisite to determine oxygen concentrations generated in vivo. Our study objective was the establishment of an invasive method for oxygen measurements using a luminescence-based microsensor to determine the dissolved oxygen in the lung tissue of ferrets as animal models for SARS-CoV-2 research. By way of analogy to humans, aged ferrets are more likely to show clinical signs after SARS-CoV-2 infection than are young animals. To investigate oxygen concentrations during a respiratory viral infection, we intratracheally infected nine aged (3-yr-old) ferrets with SARS-CoV-2. The aged SARS-CoV-2-infected ferrets showed mild to moderate clinical signs associated with prolonged viral RNA shedding until 14 days postinfection. SARS-CoV-2-infected ferrets showed histopathologic lung lesion scores that significantly negatively correlated with oxygen concentrations in lung tissue. At 4 days postinfection, oxygen concentrations in lung tissue were significantly lower (mean percentage O2, 3.89 ≙ ≈ 27.78 mm Hg) than in the negative control group (mean percentage O2, 8.65 ≙ ≈ 61.4 mm Hg). In summary, we succeeded in determining the pathophysiologic oxygen conditions in the lung tissue of aged SARS-CoV-2-infected ferrets.

Cytokines from SARS-CoV-2 Spike-Activated Macrophages Hinder Proliferation and Cause Cell Dysfunction in Endothelial Cells

Endothelial dysfunction plays a central role in the severity of COVID-19, since the respiratory, thrombotic and myocardial complications of the disease are closely linked to vascular endothelial damage. To address this issue, we evaluate here the effect of conditioned media from spike S1-activated macrophages (CM_S1) on the proliferation of human umbilical endothelial cells (HUVECs), focusing on the specific role of interleukin-1-beta (IL-1β), interleukin-6 (IL-6), interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). Results obtained demonstrate that the incubation with CM_S1 for 72 h hinders endothelial cell proliferation and induces signs of cytotoxicity. Comparable results are obtained upon exposure to IFN-γ + TNF-α, which are thus postulated to play a pivotal role in the effects observed. These events are associated with an increase in p21 protein and a decrease in Rb phosphorylation, as well as with the activation of IRF-1 and NF-kB transcription factors. Overall, these findings further sustain the pivotal role of a hypersecretion of inflammatory cytokines as a trigger for endothelial activation and injury in the immune-mediated effects of COVID-19.

Interplay of TLR4 and SARS-CoV-2: Unveiling the Complex Mechanisms of Inflammation and Severity in COVID-19 Infections

The late 2019 emergence of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, caused profound and unprecedented disruption to the global socio-economic structure, negatively affecting millions of lives worldwide. A typical hallmark of severe COVID-19 is hyper inflammation due to aberrant cytokine release (cytokine storm) by innate immune cells. Recent studies have revealed that SARS-CoV-2, through its spike (S) protein, can activate the body's innate immune cells via Toll-Like Receptors (TLRs), particularly TLR4. In silico studies have demonstrated that the S protein binds with high affinity to TLR4, triggering downstream signaling processes that result in pro-inflammatory cytokine release. Compared to other TLRs, such as TLR2, TLR4 plays a more significant role in initiating and sustaining the inflammatory response associated with severe COVID-19. Furthermore, interactions between the virus and target cells can enhance the cellular expression of TLR4, making cells more susceptible to viral interactions and subsequent inflammation. This increased expression of TLR4 upon viral entry creates a feedback loop, where heightened TLR4 levels lead to amplified inflammatory responses, contributing to the severity of the disease. Additionally, TLR4's potent activation of inflammatory pathways sets it apart from other TLRs, underscoring its pivotal role in the pathogenesis of COVID-19. In this review, we thoroughly explore the multitude of regulatory signaling pathways that SARS-CoV-2 employs to incite inflammation. We specifically focus on the critical impact of TLR4 activation compared to other TLRs, highlighting how TLR4's interactions with the viral S protein can exacerbate the severity of COVID-19. By delving into the mechanisms of TLR4-mediated inflammation, we aim to shed light on potential therapeutic targets that could mitigate the inflammatory damage caused by severe COVID-19. Understanding the unique role of TLR4 in the context of SARS-CoV-2 infection could pave the way for novel treatment strategies that specifically inhibit this receptor's activity, thereby reducing the overall disease burden and improving patient outcomes.

Neurological Complications of COVID-19 Infection: A Comprehensive Review

The COVID-19 pandemic is well on its way to reaching endemic status across the globe. While the medical community's understanding of the respiratory complications induced by COVID-19 is improving, there is still much to be learned about the neurological manifestations associated with COVID-19 infection. This review aimed to compile relevant, available evidence of COVID-19-induced neurological complications and to provide information for each complication regarding symptomology, progression patterns, demographic risk factors, treatment, and causative mechanism of action when available. Data for this review was collected using a confined search on PubMed using the keywords ["COVID-19" OR "SARS-CoV-2"] AND ["neurological complications" OR "olfactory symptoms" OR "gustatory symptoms" OR "myalgia" OR "headache" OR "dizziness" OR "stroke" OR "seizures" OR "meningoencephalitis" OR "cerebellar ataxia" OR "acute myelitis" OR "Guillain Barré Syndrome" OR "Miller Fisher Syndrome" OR "Posterior Reversible Encephalopathy Syndrome"] between 2019 and 2023. A wide range of neurological manifestations impact a significant percentage of COVID-19 patients, and a deeper understanding of these manifestations is necessary to ensure adequate management. The most common neurological complications identified consist of olfactory and gustatory dysfunctions, myalgia, headache, and dizziness, while the most severe complications include stroke, seizures, meningoencephalitis, Guillain-Barré syndrome, Miller Fisher syndrome, acute myelitis, and posterior reversible encephalopathy syndrome. While this review effectively provides a roadmap of the neurological risks posed to COVID-19 patients, further research is needed to clarify the precise incidence of these complications and to elucidate the mechanisms responsible for their manifestation.

Aprotinin (II): Inhalational Administration for the Treatment of COVID-19 and Other Viral Conditions

Aprotinin is a broad-spectrum inhibitor of human proteases that has been approved for the treatment of bleeding in single coronary artery bypass surgery because of its potent antifibrinolytic actions. Following the outbreak of the COVID-19 pandemic, there was an urgent need to find new antiviral drugs. Aprotinin is a good candidate for therapeutic repositioning as a broad-spectrum antiviral drug and for treating the symptomatic processes that characterise viral respiratory diseases, including COVID-19. This is due to its strong pharmacological ability to inhibit a plethora of host proteases used by respiratory viruses in their infective mechanisms. The proteases allow the cleavage and conformational change of proteins that make up their viral capsid, and thus enable them to anchor themselves by recognition of their target in the epithelial cell. In addition, the activation of these proteases initiates the inflammatory process that triggers the infection. The attraction of the drug is not only its pharmacodynamic characteristics but also the possibility of administration by the inhalation route, avoiding unwanted systemic effects. This, together with the low cost of treatment (≈2 Euro/dose), makes it a good candidate to reach countries with lower economic means. In this article, we will discuss the pharmacodynamic, pharmacokinetic, and toxicological characteristics of aprotinin administered by the inhalation route; analyse the main advances in our knowledge of this medication; and the future directions that should be taken in research in order to reposition this medication in therapeutics.

Extracellular matrix remodelling pathway in peripheral blood mononuclear cells from severe COVID-19 patients: an explorative study

There is a reciprocal relationship between extracellular matrix (ECM) remodelling and inflammation that could be operating in the progression of severe COVID-19. To explore the immune-driven ECM remodelling in COVID-19, we in this explorative study analysed these interactions in hospitalised COVID-19 patients. RNA sequencing and flow analysis were performed on peripheral blood mononuclear cells. Inflammatory mediators in plasma were measured by ELISA and MSD, and clinical information from hospitalised COVID-19 patients (N=15) at admission was included in the analysis. Further, we reanalysed two publicly available datasets: (1) lung tissue RNA-sequencing dataset (N=5) and (2) proteomics dataset from PBCM. ECM remodelling pathways were enriched in PBMC from COVID-19 patients compared to healthy controls. Patients treated at the intensive care unit (ICU) expressed distinct ECM remodelling gene profiles compared to patients in the hospital ward. Several markers were strongly correlated to immune cell subsets, and the dysregulation in the ICU patients was positively associated with plasma levels of inflammatory cytokines and negatively associated with B-cell activating factors. Finally, our analysis of publicly accessible datasets revealed (i) an augmented ECM remodelling signature in inflamed lung tissue compared to non-inflamed tissue and (ii) proteomics analysis of PBMC from severe COVID-19 patients demonstrated an up-regulation in an ECM remodelling pathway. Our results may suggest the presence of an interaction between ECM remodelling, inflammation, and immune cells, potentially initiating or perpetuating pulmonary pathology in severe COVID-19.

Imaging of the Spectrum of Acute Lung Injury

Organizing pneumonia, acute fibrinous and organizing pneumonia, and diffuse alveolar damage, represent multi-compartment patterns of lung injury. The initial region of injury in all remains the same and is centered on the fused basement membrane (BM) between the capillary endothelium and type I pneumocyte. Injury leads to cellular death, BM denudation, increased cellular permeability, and BM structural damage, which leads to exudation, organization, and attempts at repair. When acute lung injury does lead to fibrosis, in some instances it can lead to histologic and/or radiologic usual interstitial pneumonia or nonspecific interstital pneumonia patterns suggesting that lung injury is the primary mechanism for the development of fibrosis.

Pulmonary inflammation and viral replication define distinct clinical outcomes in fatal cases of COVID-19

COVID-19 has affected more than half a billion people worldwide, with more than 6.3 million deaths, but the pathophysiological mechanisms involved in lethal cases and the host determinants that determine the different clinical outcomes are still unclear. In this study, we assessed lung autopsies of 47 COVID-19 patients and examined the inflammatory profiles, viral loads, and inflammasome activation. Additionally, we correlated these factors with the patient's clinical and histopathological conditions. Robust inflammasome activation was detected in the lungs of lethal cases of SARS-CoV-2. Experiments conducted on transgenic mice expressing hACE2 and infected with SARS-CoV-2 showed that Nlrp3-/- mice were protected from disease development and lethality compared to Nlrp3+/+ littermate mice, supporting the involvement of this inflammasome in disease exacerbation. An analysis of gene expression allowed for the classification of COVID-19 patients into two different clusters. Cluster 1 died with higher viral loads and exhibited a reduced inflammatory profile than Cluster 2. Illness time, mechanical ventilation time, pulmonary fibrosis, respiratory functions, histopathological status, thrombosis, viral loads, and inflammasome activation significantly differed between the two clusters. Our data demonstrated two distinct profiles in lethal cases of COVID-19, thus indicating that the balance of viral replication and inflammasome-mediated pulmonary inflammation led to different clinical outcomes. We provide important information to understand clinical variations in severe COVID-19, a process that is critical for decisions between immune-mediated or antiviral-mediated therapies for the treatment of critical cases of COVID-19.

Pulmonary drug delivery devices and nanosystems as potential treatment strategies for acute respiratory distress syndrome (ARDS)

Despite advances in drug delivery technologies, treating acute respiratory distress syndrome (ARDS) is challenging due to pathophysiological barriers such as lung injury, oedema fluid build-up, and lung inflammation. Active pharmaceutical ingredients (API) can be delivered directly to the lung site of action with the use of aerosol-based drug delivery devices, and this circumvents the hepatic first-pass effect and improves the bioavailability of drugs. This review discusses the various challenges and barriers for pulmonary drug delivery, current interventions for delivery, considerations for effective drug delivery, and the use of nanoparticle drug delivery carriers as potential strategies for delivering therapeutics in ARDS. Nanosystems have the added benefit of entrapping drugs, increase pulmonary drug bioavailability, and using biocompatible and biodegradable excipients that can facilitate targeted and/or controlled delivery. These systems provide an alternative to existing conventional systems. An effective way to deliver drugs for the treatment of ARDS can be by using colloidal systems that are aerosolized or inhaled. Drug distribution to the deeper pulmonary tissues is necessary due to the significant endothelial cell destruction that is prevalent in ARDS. The particle size of nanoparticles (<0.5 μm) makes them ideal candidates for treating ARDS as they can reach the alveoli. A look into the various potential benefits and limitations of nanosystems used for other lung disorders is also considered to indicate how they may be useful for the potential treatment of ARDS.

Vitamin D level in COVID-19 patients has positive correlations with autophagy and negative correlations with disease severity

Background and Objectives

There is still incomplete understanding of the pathogenesis of COVID-19. Calcitriol, the main form of vitamin D in serum, regulates immune responses and increases resistance to pathogens, but the mechanism by which it protects against COVID-19 is uncertain. Autophagy has antiviral effects and helps to maintain homeostasis, but its specific role in COVID-19 is also uncertain. Both vitamin D and autophagy have important functions in the lung microenvironment. This study examined the relationship of serum vitamin D and autophagy-related proteins in patients with COVID-19 and evaluated their potential use as biomarkers.

Methods

Blood samples from COVID-19 patients at the Second Hospital of Jilin University were collected. The levels of vitamin D, autophagy-related proteins (Becline 1 [BECN1] and autophagy-related 7 [ATG7]), and inflammatory markers (TNF-α and IL-1β) were measured using enzyme-linked immunosorbent assays.

Results

We examined 25 patients with mild/moderate COVID-19 and 27 patients with severe/critical COVID-19. The group with severe/critical COVID-19 had more abnormalities in many laboratory indicators, including lower levels of autophagy markers (BECN1 and ATG7) and vitamin D, and higher levels of inflammatory markers (TNF-α and IL-1β). Partial correlation analysis showed that vitamin D had strong positive correlations with ATG7 (r = 0.819, p < 0.001) and BECN1 (r = 0.900, p < 0.001).

Conclusion

Our results demonstrated that the vitamin D level had significant negative correlations with COVID-19 severity and strong positive correlations with autophagy. These findings enhance our understanding of the pathogenesis of COVID-19, and provide a theoretical basis for clinical interventions that target autophagy and vitamin D.

Lung volume measurement using chest CT in COVID-19 patients: a cohort study in Japan

OBJECTIVE

This study aimed to investigate the utility of CT quantification of lung volume for predicting critical outcomes in COVID-19 patients.

METHODS

This retrospective cohort study included 1200 hospitalised patients with COVID-19 from 4 hospitals. Lung fields were extracted using artificial intelligence-based segmentation, and the percentage of the predicted (%pred) total lung volume (TLC (%pred)) was calculated. The incidence of critical outcomes and posthospitalisation complications was compared between patients with low and high CT lung volumes classified based on the median percentage of predicted TLCct (n=600 for each). Prognostic factors for residual lung volume loss were investigated in 208 patients with COVID-19 via a follow-up CT after 3 months.

RESULTS

The incidence of critical outcomes was higher in the low TLCct (%pred) group than in the high TLCct (%pred) group (14.2% vs 3.3%, p<0.0001). Multivariable analysis of previously reported factors (age, sex, body mass index and comorbidities) demonstrated that CT-derived lung volume was significantly associated with critical outcomes. The low TLCct (%pred) group exhibited a higher incidence of bacterial infection, heart failure, thromboembolism, liver dysfunction and renal dysfunction than the high TLCct (%pred) group. TLCct (%pred) at 3 months was similarly divided into two groups at the median (71.8%). Among patients with follow-up CT scans, lung volumes showed a recovery trend from the time of admission to 3 months but remained lower in critical cases at 3 months.

CONCLUSION

Lower CT lung volume was associated with critical outcomes, posthospitalisation complications and slower improvement of clinical conditions in COVID-19 patients.

Role of Hypoxia-Inducible Factor 1α in Adaptation to Hypoxia in the Pathogenesis of Novel Coronavirus Disease 2019

INTRODUCTION: A novel coronavirus (severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2)) emerged in December 2019 and rapidly spread over the world having provoked a pandemic of respiratory disease. This highly pathogenic virus can attack the lung tissue and derange gas exchange leading to acute respiratory distress syndrome and systemic hypoxia. Hypoxic conditions trigger activation of adaptation mechanisms including hypoxia-inducible factor-1á (HIF-1á) which is involved in the regulation of the key processes, e. g, proliferation and metabolism of cells and angiogenesis. Besides, the level of HIF-1á expression is associated with the intensity of the immune response of an organism including that of the innate immunity mediating inflammatory reaction. Therefore, understanding the peculiarities of the mechanisms underlying the pathogenesis of this disease is of great importance for effective therapy of coronavirus disease 2019 (COVID-19). AIM: Analysis of the current data on HIF-1á and its effect on the pathogenesis and progression of COVID-19. The analysis of the relevant domestic and international literature sources was performed in the following sections: HIF-1á as a key factor of adaptation to hypoxia, targets for HIF-1á in the aspect of the pathogenesis of COVID-19, disorders in HIF-1á-mediated adaptation to hypoxia as an element of the pathogenesis of hyperactivation of the immune cells. CONCLUSION: HIF-1á prevents penetration of SARS-CoV-2 virus into a cell and primarily acts as the main regulator of the proinflammatory activity at the inflammation site surrounded by hypoxia. In the conditions of the deranged metabolic flexibility, a high level of HIF-1á evokes an excessive inflammatory response of the immune cells. A high HIF-1á level in cells of the inflammation focus is associated with enhanced production of the factors of angiogenesis mediating vascular permeability and capillary leakage process. This is accompanied by tissue damage and organ failure. At the same time, HIF-1á can mediate the anti-inflammatory effect through activation of adenosine receptor-dependent pathway, which is considered as a probable protection of cells and organs against damage by hyperactive immune cells.

Infection kinetics, syncytia formation, and inflammatory biomarkers as predictive indicators for the pathogenicity of SARS-CoV-2 Variants of Concern in Calu-3 cells

The ongoing COVID-19 pandemic has led to the emergence of new SARS-CoV-2 variants as a result of continued host-virus interaction and viral genome mutations. These variants have been associated with varying levels of transmissibility and disease severity. We investigated the phenotypic profiles of six SARS-CoV-2 variants (WT, D614G, Alpha, Beta, Delta, and Omicron) in Calu-3 cells, a human lung epithelial cell line. In our model demonstrated that all variants, except for Omicron, had higher efficiency in virus entry compared to the wild-type. The Delta variant had the greatest phenotypic advantage in terms of early infection kinetics and marked syncytia formation, which could facilitate cell-to-cell spreading, while the Omicron variant displayed slower replication and fewer syncytia formation. We also identified the Delta variant as the strongest inducer of inflammatory biomarkers, including pro-inflammatory cytokines/chemokines (IP-10/CXCL10, TNF-α, and IL-6), anti-inflammatory cytokine (IL-1RA), and growth factors (FGF-2 and VEGF-A), while these inflammatory mediators were not significantly elevated with Omicron infection. These findings are consistent with the observations that there was a generally more pronounced inflammatory response and angiogenesis activity within the lungs of COVID-19 patients as well as more severe symptoms and higher mortality rate during the Delta wave, as compared to less severe symptoms and lower mortality observed during the current Omicron wave in Thailand. Our findings suggest that early infectivity kinetics, enhanced syncytia formation, and specific inflammatory mediator production may serve as predictive indicators for the virulence potential of future SARS-CoV-2 variants.

High-resolution Computed Tomography Thorax Volumetric Assessment in Coronavirus Disease 2019 Patients and Correlation with Pulmonary Function Tests

INTRODUCTION

Years after SARS coronavirus disease 2019 (COVID-19) recovery, residual pulmonary abnormalities may still exist. This brings on the question of whether or not COVID-19 could have comparable late consequences. Structural changes in the lungs after recovery can be better visualized using computed tomography (CT) thorax. Computed Tomography Lung Parenchymal changes during hospitalization by COVID-19 and after 4 months of follow-up to correlate with the volumetric high-resolution computed tomography thorax indices, Pulmonary function tests (PFTs) indices, SpO2, and 6 min Walking Test (6MWT).

MATERIALS AND METHODS

This is a Hospital based cross-sectional study, with a follow-up among 100 Patients from 2020 to 2022. Each patient's different CT parameters and HRCT volumetric indices Normal Lung (NL), Normal Lung Percentage (NL%), Whole Lung (WL) were correlated with the PFT indices (Forced expiratory volume in 1s [FEV1], forced vital capacity [FVC], FEV1/FVC), Oxygen Saturation (SpO2) and 6-Minute Walking Test (6MWT).

RESULTS

The mean NL (L) and NL% during COVID were significantly lower than the mean values 4 months post-COVID. Architectural distortion, bronchiolar dilatation, interstitial thickening, and parenchymal bands were reduced considerably after 4 months post-COVID, compared to during COVID. PFTs results, such as PFT indices, were not significantly different after 4 months post-COVID, compared to during COVID. SpO2 (%) and 6 MWT (m) were significantly increased. During COVID and post-COVID, the values of NL (L) and NL (%) had a significant positive correlation with PFT indices, SpO2, and 6MWT (m).

CONCLUSION

Hence, the different CT indices (NL and NL%) can be used as a surrogate for functional recovery of COVID patients since it correlates with the PFT indices (FEV1 and FEV1/FVC), SpO2, and 6MWT post-COVID.

Factors of Interleukin-6 Signaling in COVID-19 Patients with Lung Damage of Varying Degrees: A Pilot Study

Specific features of IL-6 signal transduction were studied in 89 patients with lung damage of varying degrees during the first COVID-19 pandemic wave. The levels of IL-6 signaling components (IL-6, sIL-6R, and sgp130) and highly sensitive C-reactive protein (hsCRP) were examined in patients with intact lungs (CT-0), mild (CT-1), moderate (CT-2), moderate to severe (CT-3), and severe (CT-4) lung damage. Seventy patients were re-examined 3-7 months after discharge from the hospital. The IL-6 and hsCRP levels increased several times with severing lung damage severity. In patients with CT-3, sIL6-R increased statistically significantly and remained high in CT-4 patients. sgp130 levels were lower in CT-1 and CT-2 patients and higher in CT-3 and CT-4 patients compared to CT-0 patients. We revealed a positive correlation between IL-6 and hsCRP levels in CT-1, CT-2, and CT-3 patients. In CT-3 patients, sIL-6R levels positively correlated with IL-6 concentration. The studied parameters decreased considerably in all patients 3-7 months after discharge. It can be suggested that IL-6 classic-signaling is predominant in CT-1 and CT-2, while trans-signaling prevails in CT-3. Disorders in regulatory mechanisms of IL-6 signaling occur in CT-4, which prevents physiological elimination of IL-6 hyperactivity. The results obtained are preliminary and require a broader study.

Serial electrical impedance tomography course in different treatment groups; The MaastrICCht cohort

PURPOSE

To describe the effect of dexamethasone and tocilizumab on regional lung mechanics over admission in all mechanically ventilated COVID-19 patients.

MATERIALS AND METHODS

Dynamic compliance, alveolar overdistension and collapse were serially determined using electric impedance tomography (EIT). Patients were categorized into three groups; no anti-inflammatory therapy, dexamethasone therapy, dexamethasone + tocilizumab therapy. The EIT variables were (I) visualized using polynomial regression, (II) evaluated throughout admission using linear mixed-effects models, and (III) average respiratory variables were compared.

RESULTS

Visual inspection of EIT variables showed a pattern of decreasing dynamic compliance. Overall, optimal set PEEP was lower in the dexamethasone group (-1.4 cmH2O, -2.6; -0.2). Clinically applied PEEP was lower in the dexamethasone and dexamethasone + tocilizumab group (-1.5 cmH2O, -2.6; -0.2; -2.2 cmH2O, -5.1; 0.6). Dynamic compliance, alveolar overdistension, and alveolar collapse at optimal set PEEP did not significantly differ between the three groups.

CONCLUSION

Optimal and clinically applied PEEP were lower in the dexamethasone and dexamethasone + tocilizumab groups. The results suggest that the potential beneficial effects of these therapies do not affect lung mechanics favorably. However, this study cannot fully rule out any beneficial effect of anti-inflammatory treatment on pulmonary function due to its observational nature.

Recommendations for Improving Chronic Care in Times of a Pandemic Based on Patient Experiences

OBJECTIVES

The COVID-19 pandemic had a profound and pervasive impact on the health of chronic care patients and disrupted care systems worldwide. Our research aimed to assess the impact of the pandemic on chronic care provision and provide recommendations for improving care provision, based on patient experiences.

DESIGN

Qualitative semi-structured interviews were held among patients with chronic obstructive pulmonary disease (COPD) or heart failure.

SETTING AND PARTICIPANTS

Using stratified sampling, 23 patients with COPD, heart failure, or both were recruited to participate in semi-structured interviews. In the summer of 2021, online interviews were conducted.

METHODS

An iterative process was adopted to analyze the data. Going back and forth through the data and our analytical structure, we first coded the data, and subsequently developed categories, themes, and aggregate dimensions. The data were synthesized in a data structure and a data table, which were analyzed using an interpretative approach.

RESULTS

We found 3 dimensions through which care might be improved: (1) proactive and adaptive health care organization and use of innovative technologies, (2) assistance in maintaining patient resilience and coping strategies, and (3) health care built on outreaching and person-centered care enabling identification of individual patient needs. Experiences of impaired accessibility to care, altered and unmet care demands and patient needs, and the negative impact of national containment strategies on patient resilience support the need for improvement in these dimensions.

CONCLUSIONS AND IMPLICATIONS

The in-depth insight gained on the impact of the pandemic on chronic care provision was used to propose recommendations for improving care, supported by not only the what and how but also the why developments require additional efforts made by policymakers and change agents, augmented by structural use and development of innovations. Health care organizations should be enabled to rapidly respond to changing internal and external environments, develop and implement innovations, and match care to patient needs.

A Hybrid Deep Learning CNN model for COVID-19 detection from chest X-rays

Coronavirus disease (COVID-2019) is emerging in Wuhan, China in 2019. It has spread throughout the world since the year 2020. Millions of people were affected and caused death to them till now. To avoid the spreading of COVID-2019, various precautions and restrictions have been taken by all nations. At the same time, infected persons are needed to identify and isolate, and medical treatment should be provided to them. Due to a deficient number of Reverse Transcription Polymerase Chain Reaction (RT-PCR) tests, a Chest X-ray image is becoming an effective technique for diagnosing COVID-19. In this work, the Hybrid Deep Learning CNN model is proposed for the diagnosis COVID-19 using chest X-rays. The proposed model consists of a heading model and a base model. The base model utilizes two pre-trained deep learning structures such as VGG16 and VGG19. The feature dimensions from these pre-trained models are reduced by incorporating different pooling layers, such as max and average. In the heading part, dense layers of size three with different activation functions are also added. A dropout layer is supplemented to avoid overfitting. The experimental analyses are conducted to identify the efficacy of the proposed hybrid deep learning with existing transfer learning architectures such as VGG16, VGG19, EfficientNetB0 and ResNet50 using a COVID-19 radiology database. Various classification techniques, such as K-Nearest Neighbor (KNN), Naive Bayes, Random Forest, Support Vector Machine (SVM), and Neural Network, were also used for the performance comparison of the proposed model. The hybrid deep learning model with average pooling layers, along with SVM-linear and neural networks, both achieved an accuracy of 92%.These proposed models can be employed to assist radiologists and physicians in avoiding misdiagnosis rates and to validate the positive COVID-19 infected cases.

Age and period of ventilator use are related to walking independence at the time of discharge in patients with severe COVID-19 pneumonia: a single-center retrospective observational study

[Purpose] This study aimed to identify the factors and cutoffs associated with walking independence in patients with severe COVID-19 pneumonia. [Participants and Methods] In total, 112 patients with COVID-19 pneumonia (98 males and 14 females) who were hospitalized between March 2020 and August 2021 and underwent physiotherapy during mechanical ventilation were included in the study. Attributes, respiratory function, physical function, and bed-withdrawal status were compared between two groups of patients, who were classified according to their ability to walk independently at discharge. The independent variables were reduced to four components by principal component analysis. Logistic regression analysis was performed with walking independence at discharge as the dependent variable. Receiver operating characteristic curves for the extracted factors were drawn, and cutoff values were calculated. [Results] At discharge, 76 patients were able to walk independently, while 36 were not. The logistic regression analysis was adjusted according to age and mechanical ventilation time. Cutoffs were an age of 56 years and a ventilation period of 7.5 days. [Conclusion] In cases of patients with severe COVID-19 pneumonia who required ventilators, age and mechanical ventilation time were associated with ambulatory independence at discharge, indicating the importance of reducing the ventilation period by providing respiratory physiotherapy, including expectoration, positioning, and weaning.

COVID-19 in the Netherlands: lessons from a nationwide query of dutch autopsy, histology, and cytology pathological reports

Since the onset of the COVID-19 pandemic, autopsies have played a valuable role in understanding the pathophysiology of COVID-19. In this study, we have analyzed COVID-19-related pathology reports from autopsies, histology, and cytology on a nationwide level. Pathology reports from all 43 pathology laboratories in the Netherlands stating "COVID," "Corona," and/or "SARS" were queried from the Dutch Nationwide Pathology Database (Palga). Consecutive reports of the included patients were also retrieved. Out of 5065 entries, a total of 1833 eligible COVID-19-related pathology reports between January 2020 and June 2021 were included in this collection of reports. Lung histopathology reports reflected differences in the severity of abnormalities (acute diffuse alveolar damage, alveolar histiocytes, and thrombi during the first three pandemic waves (Wuhan variant) versus the fourth wave (alpha variant)). Autopsy reports from 2020 state significantly shorter disease duration and younger age of death compared to autopsy reports from 2021. All reports together reflected a more granular pathology with comorbidities such as chronic histiocytic intervillositis, perniosis, and thrombi found in a variety of organs (lungs, kidneys, and small and large intestines). This nationwide overview of pathology reports provides data related to deaths as well as comorbidities in a clinical setting of COVID-19. Certain findings reported in SARS-CoV-infected lungs and placentas were also reported in post-COVID-19 tissue of the same kind. Consecutive reports after the earliest reports with COVID-19 allowed for follow-up reports. These follow-up reports can help with post-viral studies regarding long-term effects of COVID-19 as well as identifying the effects of different SARS-CoV-2 variants.

Neutrophil Activity and Extracellular Matrix Degradation: Drivers of Lung Tissue Destruction in Fatal COVID-19 Cases and Implications for Long COVID

Pulmonary fibrosis, severe alveolitis, and the inability to restore alveolar epithelial architecture are primary causes of respiratory failure in fatal COVID-19 cases. However, the factors contributing to abnormal fibrosis in critically ill COVID-19 patients remain unclear. This study analyzed the histopathology of lung specimens from eight COVID-19 and six non-COVID-19 postmortems. We assessed the distribution and changes in extracellular matrix (ECM) proteins, including elastin and collagen, in lung alveoli through morphometric analyses. Our findings reveal the significant degradation of elastin fibers along the thin alveolar walls of the lung parenchyma, a process that precedes the onset of interstitial collagen deposition and widespread intra-alveolar fibrosis. Lungs with collapsed alveoli and organized fibrotic regions showed extensive fragmentation of elastin fibers, accompanied by alveolar epithelial cell death. Immunoblotting of lung autopsy tissue extracts confirmed elastin degradation. Importantly, we found that the loss of elastin was strongly correlated with the induction of neutrophil elastase (NE), a potent protease that degrades ECM. This study affirms the critical role of neutrophils and neutrophil enzymes in the pathogenesis of COVID-19. Consistently, we observed increased staining for peptidyl arginine deiminase, a marker for neutrophil extracellular trap release, and myeloperoxidase, an enzyme-generating reactive oxygen radical, indicating active neutrophil involvement in lung pathology. These findings place neutrophils and elastin degradation at the center of impaired alveolar function and argue that elastolysis and alveolitis trigger abnormal ECM repair and fibrosis in fatal COVID-19 cases. Importantly, this study has implications for severe COVID-19 complications, including long COVID and other chronic inflammatory and fibrotic disorders.

The effectiveness of glucocorticoid treatment in post-COVID-19 pulmonary involvement

RATIONALE

Persistent respiratory symptoms following Coronavirus Disease 2019 (COVID-19) are associated with residual radiological changes in lung parenchyma, with a risk of development into lung fibrosis, and with impaired pulmonary function. Previous studies hinted at the possible efficacy of corticosteroids (CS) in facilitating the resolution of post-COVID residual changes in the lungs, but the available data is limited.

AIM

To evaluate the effects of CS treatment in post-COVID respiratory syndrome patients.

PATIENTS AND METHODS

Post-COVID patients were recruited into a prospective single-center observational study and scheduled for an initial (V1) and follow-up visit (V2) at the Department of Respiratory Medicine and Tuberculosis, University Hospital Olomouc, comprising of pulmonary function testing, chest x-ray, and complex clinical examination. The decision to administer CS or maintain watchful waiting (WW) was in line with Czech national guidelines.

RESULTS

The study involved 2729 COVID-19 survivors (45.7% male; mean age: 54.6). From 2026 patients with complete V1 data, 131 patients were indicated for CS therapy. These patients showed significantly worse radiological and functional impairment at V1. Mean initial dose was 27.6 mg (SD ± 10,64), and the mean duration of CS therapy was 13.3 weeks (SD ± 10,06). Following therapy, significantly better improvement of static lung volumes and transfer factor for carbon monoxide (DLCO), and significantly better rates of good or complete radiological and subjective improvement were observed in the CS group compared to controls with available follow-up data (n = 894).

CONCLUSION

Better improvement of pulmonary function, radiological findings and subjective symptoms were observed in patients CS compared to watchful waiting. Our findings suggest that glucocorticoid therapy could benefit selected patients with persistent dyspnea, significant radiological changes, and decreased DLCO.

Myocardial Oedema as a Consequence of Viral Infection and Persistence-A Narrative Review with Focus on COVID-19 and Post COVID Sequelae

Microvascular integrity is a critical factor in myocardial fluid homeostasis. The subtle equilibrium between capillary filtration and lymphatic fluid removal is disturbed during pathological processes leading to inflammation, but also in hypoxia or due to alterations in vascular perfusion and coagulability. The degradation of the glycocalyx as the main component of the endothelial filtration barrier as well as pericyte disintegration results in the accumulation of interstitial and intracellular water. Moreover, lymphatic dysfunction evokes an increase in metabolic waste products, cytokines and inflammatory cells in the interstitial space contributing to myocardial oedema formation. This leads to myocardial stiffness and impaired contractility, eventually resulting in cardiomyocyte apoptosis, myocardial remodelling and fibrosis. The following article reviews pathophysiological inflammatory processes leading to myocardial oedema including myocarditis, ischaemia-reperfusion injury and viral infections with a special focus on the pathomechanisms evoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition, clinical implications including potential long-term effects due to viral persistence (long COVID), as well as treatment options, are discussed.

Bosentan and Pulmonary Hypertension Caused by COVID-19: A Pilot Randomized Double-blind Clinical Study

INTRODUCTION/OBJECTIVE

Coronavirus disease 2019 (COVID-19) has been the biggest pandemic in history, with severe complications, such as acute respiratory distress syndrome and pulmonary hypertension (PH). An endothelin-1 (ET-1) receptor antagonist, such as bosentan, may be beneficial in treating elevated ET-1 levels. Hence, our study aimed to evaluate the therapeutic effects of bosentan in patients with COVID-19-induced PH.

METHODS

A single-centre, randomized, double-blind study involving 72 participants was carried out; 36 received bosentan and the other 36 received a placebo. Pulmonary arterial pressure, tricuspid valve pressure gradient, and right atrial pressure were measured using echocardiography. The Cox proportional hazards regression model was used to investigate the impact of bosentan and patients' age on mortality during a 6-month follow-up period.

RESULTS

In-hospital mortality was significantly lower in the case group (13%) compared with the control group (33.3%) (P=0.003). Additionally, bosentan improved echocardiographic parameters, such as systolic pulmonary artery pressure and tricuspid regurgitation gradient (P=0.011 and P=0.003, respectively). Bosentan use was a significant predictor of long-term mortality rates for 600 days [age-adjusted hazard ratio of 5.24 (95% CI 1.34 to 20.46)].

CONCLUSION

This study provided a mixed perspective on the use of bosentan therapy in patients with COVID-19-related PH. Bosentan effectively reduced in-hospital mortality and improved echocardiographic measures. However, the treatment group showed an increased requirement for supplemental oxygen therapy and long-term mortality. Further studies with larger sample sizes are necessary to elucidate the effects of bosentan in PH following COVID-19.

Catalase: A Potential Pharmacologic Target for Hydrogen Peroxide in the Treatment of COVID-19

BACKGROUND

Acute respiratory distress syndrome in the elderly with COVID-19 complicated by airway obstruction with sputum and mucus, and cases of asphyxia with blood, serous fluid, pus, or meconium in newborns and people of different ages can sometimes cause hypoxemia and death from hypoxic damage to brain cells, because the medical standard does not include intrapulmonary injections of oxygen-producing solutions. The physical-chemical repurposing of hydrogen peroxide from an antiseptic to an oxygen-producing antihypoxant offers hope for the development of new drugs.

METHODS

This manuscript is a meta-analysis performed according to PRISMA guidelines.

RESULTS

It is shown that replacement of the traditional acidic activity of hydrogen peroxide solutions by alkaline activity with pH 8.4 and heating the solutions to the temperature of +37 - +42 °C allows to repurpose hydrogen peroxide from antiseptics into inhalation and intrapulmonary mucolytics, pyolytics and antihypoxants releasing oxygen. The fact is that warm alkaline hydrogen peroxide solution (WAHPS) in local interaction with sputum, mucus, pus, blood and meconium provides optimal conditions for the metabolism of hydrogen peroxide to oxygen gas under the action of the enzyme catalase, always present in these tissues. It was established that WAHPS liquefies these biological masses due to alkaline saponification of lipid and protein-lipid complexes and simultaneously transforms dense masses into soft oxygen foam due to active enzymatic metabolism of hydrogen peroxide to oxygen gas, the rapidly appearing bubbles of which are formed by the type of "cold boiling" and literally explode these masses. The results of the first experiments showed that inhalation and intrapulmonary injections of WAHPS can significantly optimize the treatment of suffocation and hypoxemia.

DISCUSSION

The results showed that catalase, which is found in sputum, mucus, pus, and blood, may be a target for localized WAHPS because this enzyme provides an intensive metabolism of hydrogen peroxide to oxygen gas up to the formation of the cold boiling process.

CONCLUSION

These data provide a new perspective way for intrapulmonary drugs and new technologies for the emergency increase of blood oxygenation through the lungs in asphyxia with thick sputum, mucus, pus, meconium and blood.

Diffuse bilateral 18F-Fluoroestradiol pulmonary uptake in patients with metastatic estrogen receptor positive breast cancer: A case report

INTRODUCTION

Breast cancer is the most commonly diagnosed cancer in women and hormonal therapy is an established treatment for estrogen receptor (ER) positive breast cancers. 18F-Fluoroestradiol (FES) is an emerging radiotracer used to determine hormone status in patients with ER positive breast cancer as FES specifically binds to the alpha subtype of estrogen receptors. As with all radiotracers, FES demonstrates background uptake within various tissues and organs besides the targeted breast cancer and metastatic disease. To date, FES has mostly been shown to demonstrate uptake within the lungs from metastatic disease or in a more focal region after radiation therapy.

CASE AND OUTCOMES

We present two patients with stage IV ER positive breast cancer who underwent FES positron emission tomography and computed tomography (PET/CT) scans to evaluate for metastatic disease; both of which demonstrated diffuse bilateral mild-moderate pulmonary uptake. The first patient had a severe lung injury which was improving but still present at the time of her FES PET/CT. The second patient had a remote history of prior right breast radiation therapy for a prior breast cancer as well as emphysema and mild interstitial disease.

DISCUSSION

To date, FES uptake within the lungs has been shown to be secondary to fibrotic changes secondary to prior radiation therapy and the uptake is localized to a focal region within the lung corresponding to the localized region around the tumor needing radiation therapy. We present two FES PET/CT scans that demonstrate diffuse bilateral mild-moderate uptake. We believe the first patient's bilateral FES uptake was secondary to inflammatory changes from her acute lung injury. Our second patient has a remote history of right breast radiation therapy that would not account for her diffuse lung uptake but does have emphysema and mild interstitial disease which can account for the FES uptake seen in her FES PET/CT.

CONCLUSION

18F-Fluoroestradiol is an emerging radiotracer that binds to estrogen receptors and is being used to determine hormone receptor status in women with ER positive breast cancers, which is the most commonly diagnosed cancer in women. Therefore, it's important to understand where it might demonstrate uptake and why. We highlighted two unique cases of mild-moderate pulmonary uptake of FES to provide further information about FES. Overall, we conclude that diffuse bilateral mild-moderate FES uptake within the lungs is likely secondary to inflammation, interstitial disease, or a combination thereof.

Efficacy and Safety of Glucocorticoid in the Treatment of Acute Respiratory Distress Syndrome caused by Covid-19: A Systematic Review and Meta-Analysis

BACKGROUND

Glucocorticoids are often used to treat acute respiratory distress syndrome (ARDS) and novel coronavirus disease 2019 (COVID-19). However, the efficacy and safety of glucocorticoids in the treatment of ARDS caused by COVID-19 are still controversial; therefore, we conducted this meta-analysis of the literature on this topic.

METHODS

Four databases (PubMed, EMBASE, Cochrane Library, and Web of Science) were searched from the establishment of the databases to August 16, 2023. Randomized controlled trials (RCTs) and cohort studies that compared glucocorticoid versus standard treatment for ARDS caused by COVID-19 were included. The Newcastle-Ottawa Scale (NOS) checklist and the Cochrane Handbook for Systematic Reviews of Interventions were used to evaluate the risk of bias. Review Manager 5.4 software and STATA 17.0 were used for meta-analy-sis, and the relative risk (RR), mean difference, and 95% confidence intervals (CIs) were then determined. Results: A total of 17 studies involving 8592 patients were evaluated, including 14 retrospective studies and 3 RCTs. Sixteen studies reported data on all-cause mortality. The results of the meta-analysis showed that glucocorticoids did not reduce all-cause (RR, 0.96; 95% CI 0.82-1.13, P = .62) or 28-day (RR, 1.01; 95% CI 0.78-1.32, P = .93) mortality. Subgroup analysis showed that only methylprednisolone reduced all-cause mortality. No matter whether glucocorticoid use was early or delayed, high-dose or low-dose, long-term or short-term, no regimen reduced all-cause mortality. Furthermore, there were no significant differences in length of intensive care unit (ICU) stay, length of hospital stay, hyperglycemia, and ventilator-associated pneumonia (VAP); how-ever, glucocorticoids increased the number of ventilator-free days.

CONCLUSIONS

Although methylprednisolone may reduce all-cause mortality from ARDS caused by COVID-19, this effect was not found with other types of glucocorticoids. At the same time, glucocorticoid use was associ-ated with more ventilator-free days, without increasing the incidence of hyperglycemic events or VAP. Con-sidering that almost all of the included studies were retrospective cohort studies, more RCTs are needed to confirm these findings.

Spleen Tyrosine Kinase phosphorylates VE-cadherin to cause endothelial barrier disruption in acute lung injury

Increased endothelial cell (EC) permeability is a cardinal feature of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Tyrosine phosphorylation of VE-cadherin is a key determinant of EC barrier disruption. However, the identity and role of tyrosine kinases in this context are incompletely understood. Here we report that Spleen Tyrosine Kinase (Syk) is a key mediator of EC barrier disruption and lung vascular leak in sepsis. Inhibition of Syk by pharmacological or genetic approaches, each reduced thrombin-induced EC permeability. Mechanistically, Syk associates with and phosphorylates VE-cadherin to cause EC permeability. To study the causal role of endothelial Syk in sepsis-induced ALI, we used a remarkably efficient and cost-effective approach based on gene transfer to generate EC-ablated Syk mice. These mice were protected against sepsis-induced loss of VE-cadherin and inflammatory lung injury. Notably, the administration of Syk inhibitor R788 (fostamatinib); currently in phase II clinical trial for the treatment of COVID-19, mitigated lung injury and mortality in mice with sepsis. These data identify Syk as a novel kinase for VE-cadherin and a druggable target against ALI in sepsis.

Effect of COVID-19 on the Long-term Cardiovascular Outcomes among Patients with Alcohol Use Disorder: A Retrospective Cohort Study Including 45,842 Patients

OBJECTIVES

This study was conducted to determine the risk of major acute cardiovascular events (MACEs) following COVID-19 among patients with alcohol use disorder (AUD).

METHODS

This is a 1-year follow-up retrospective cohort study that used data from TriNetX, a multi-institutional research network platform. We compared the risks of incident MACEs in patients with AUD who had a positive diagnosis for COVID-19 and patients who had not had COVID-19 during the follow-up year.

RESULTS

We enrolled 45,842 patients with AUD with and without COVID-19 history who had similar baseline characteristics from matching. During the follow-up period, the patients with AUD with COVID-19 history had a higher risk of overall MACEs than that of those without COVID-19 history (hazard ratio [HR], 2.013; 95% confidence interval [CI], 1.810-2.240). In addition, the patients with AUD with COVID-19 history had a higher risk of myocardial infarction (HR, 3.778; 95% CI, 2.873-4.969), stroke (HR, 2.411; 95% CI, 2.016-2.883), heart failure (HR, 2.206; 95% CI, 1.866-2.607), arrhythmia (HR, 2.359; 95% CI, 2.041-2.727), and inflammatory heart disease (HR, 3.042; 95% CI, 1.976-4.682).

CONCLUSIONS

Patients with AUD who survived COVID-19 had a significantly higher risk of incident cardiovascular diseases within 12 months than that of the patients with AUD without COVID-19 history.

Alismol Purified from the Tuber of Alisma orientale Relieves Acute Lung Injury in Mice via Nrf2 Activation

Since the ethanol extract of Alisma orientale Juzepzuk (EEAO) suppresses lung inflammation by suppressing Nuclear Factor-kappa B (NF-κB) and activating Nuclear Factor Erythroid 2-related Factor 2 (Nrf2), we set out to identify chemicals constituting EEAO that suppress lung inflammation. Here, we provide evidence that among the five most abundant chemical constituents identified by Ultra Performance Liquid Chromatography (UPLC) and Nuclear Magnetic Resonance (NMR), alismol is one of the candidate constituents that suppresses lung inflammation in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model and protects mice from ALI-like symptoms. Alismol did not induce cytotoxicity or reactive oxygen species (ROS). When administered to the lung of LPS-induced ALI mice (n = 5/group), alismol decreased the level of neutrophils and of the pro-inflammatory molecules, including Tumor Necrosis Factor-alpha (TNF-α), Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), Monocyte Chemoattractant Protein-1 (MCP-1), Interferon-gamma (IFN-γ), and Cyclooxygenase-2 (COX-2), suggesting an anti-inflammatory activity of alismol. Consistent with these findings, alismol ameliorated the key features of the inflamed lung of ALI, such as high cellularity due to infiltrated inflammatory cells, the development of hyaline membrane structure, and capillary destruction. Unlike EEAO, alismol did not suppress NF-κB activity but rather activated Nrf2. Consequently, alismol induced the expression of prototypic genes regulated by Nrf2, including Heme Oxygenase-1 (HO-1), NAD(P)H: quinine oxidoreductase-1 (NQO-1), and glutamyl cysteine ligase catalytic units (GCLC). Alismol activating Nrf2 appears to be associated with a decrease in the ubiquitination of Nrf2, a key suppressive mechanism for Nrf2 activity. Together, our results suggest that alismol is a chemical constituent of EEAO that contributes at least in part to suppressing some of the key features of ALI by activating Nrf2.

Role of interleukin 6 and its soluble receptor on the diffusion barrier dysfunction of alveolar tissue

During respiratory infection, barrier dysfunction in alveolar tissue can result from "cytokine storm" caused by overly reactive immune response. Particularly, interleukin 6 (IL-6) is implicated as a key biomarker of cytokine storm responsible for and further progression to pulmonary edema. In this study, alveolar-like tissue was reconstructed in a microfluidic device with: (1) human microvascular lung endothelial cells (HULEC-5a) cultured under flow-induced shear stress and (2) human epithelial cells (Calu-3) cultured at air-liquid interface. The effects of IL-6 and the soluble form of its receptor (sIL-6R) on the permeability, electrical resistance, and morphology of the endothelial and epithelial layers were evaluated. The diffusion barrier properties of both the endothelial and epithelial layers were significantly degraded only when IL-6 treatment was combined with sIL-6R. As suggested by recent review and clinical studies, our results provide unequivocal evidence that the barrier dysfunction occurs through trans-signaling in which IL-6 and sIL-6R form a complex and then bind to the surface of endothelial and epithelial cells, but not by classical signaling in which IL-6 binds to membrane-expressed IL-6 receptor. This finding suggests that the role of both IL-6 and sIL-6R should be considered as important biomarkers in developing strategies for treating cytokine storm.

Clinical analysis of prolonged viral clearance time in patients with lymphoma combined with novel coronavirus infection

Objective: To compare the period of viral clearance and its influencing factors after severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection between patients with lymphoma and lung cancer. Methods: We retrospectively collected the clinical data of patients with lymphoma and lung cancer (118 cases) diagnosed with SARS-CoV-2 infection and hospitalized in the First Affiliated Hospital of Anhui Medical University between 1 December 2022, and 15 March 2023. Finally, 87 patients with prolonged virus clearance times were included and divided into lymphoma (40 cases) and lung cancer (47 cases) groups. We used the Kaplan-Meier method to draw a negative turn curve. We performed a univariate analysis of the prolongation of virus clearance time and a Cox regression model for multivariate analysis. Results: The median times for viral clearance in the lung cancer and lymphoma groups were 18 (95% confidence interval [CI] 15.112-20.888) and 32 (95%CI 27.429-36.571) days, respectively. Log-rank analysis showed a statistically significant difference (p = 0.048), and the lymphocyte count in the lymphoma group was lower than that in the lung cancer group (p = 0.044). We used the Cox regression model to conduct a multivariate analysis, which revealed that in lymphoma patients, the interval between the time of diagnosis and the time of SARS-CoV-2 infection <24 months (hazard ratio [HR]: 0.182, 95%CI: 0.062-0.535, p = 0.02), an interval between the last anti-CD20 monoclonal antibody treatment and the time of SARS-CoV-2 infection of <2 months (HR: 0.101, 95%CI: 0.029-0.358, p < 0.001), and a decrease in peripheral blood lymphocyte levels (HR: 0.380, 95%CI: 0.179-0.808, p = 0.012) were independent risk factors for prolonged viral clearance time. Conclusion: Patients with lymphoma combined with SARS-CoV-2 infection had a longer virus clearance time than did patients with lung cancer. Moreover, the lymphocyte count in the lymphoma group was lower than that in the lung cancer group; therefore, the immune status of patients with lymphoma is lower than that of patients with lung cancer. An interval between lymphoma diagnosis and SARS-CoV-2 infection of <2 years, anti-CD20 monoclonal antibody treatment within the past 2 months, and a decrease in lymphocyte levels in the peripheral blood prolonged the virus clearance time in the patients in this study.

Predictive Value of Pulmonary Involvement in Stroke Patients Co-Infected with COVID-19

In response to the intricate clinical challenges posed by the intersection of COVID-19 and acute ischemic stroke, the Neuropsychiatry Hospital of Craiova, Romania, initiated a comprehensive study. This research aims to unravel the impacts of pulmonary complications on ischemic stroke outcomes, comparing patients with concurrent SARS-CoV-2 infection to those without. The study integrates pulmonary assessments, acknowledging the significant role respiratory involvement plays in the progression and prognosis of stroke patients during the pandemic. By systematically examining individuals with both acute ischemic stroke and COVID-19, the study seeks to shed light on the complex interplay between cerebral and pulmonary health. The findings are expected to enhance patient care by informing clinical decisions and leading to more effective management approaches for stroke patients in the COVID-19 era.