Prognostic Value of Response to Inhaled Nitric Oxide Administration in Patients with ARDS Related to SARS-CoV-2 Infection (preprint)

Background: The role of inhaled Nitric Oxide (iNO) in managing Acute Respiratory Distress Syndrome Covid-19 related (C-ARDS) is debatable. The study aimed to analyze the effect of iNO administration in patients with persistent severe hypoxia and Intensive Care Unit (ICU) mortality. Methods: This retrospective study included 98 consecutive critically ill patients with C-ARDS admitted to ICU from 1 October 2020 to 31 October 2021. Results: Of these patients, 28% had received iNO. Twelve (44.4%) were responders. Kaplan-Mayer plot shows mortality was higher in non-responders (86.6 vs 25.0%). Non-response to iNo was the most important predictive value (p. 0.01). The Receiver Operating Characteristic (ROC) curve for a percentage increase in PaO2 from baseline confirmed that it had a higher predictive value for in-hospital survival. A value of 19% can predict the death event with a sensitivity of 81.8% and a specificity of 81.2%. Conclusions: Therefore, we propose to use iNO as a vasoreactivity test for prognostic stratification in patients with persistent severe hypoxia.

Effect of apigetrin in pseudo-SARS-CoV-2-induced inflammatory and pulmonary fibrosis in vitro model (preprint)

SARS-CoV-2 has become a global public health problem. Acute respiratory distress syndrome (ARDS) is the leading cause of death due to the SARS-CoV-2 infection. Pulmonary fibrosis (PF) is a severe and frequently reported COVID-19 sequela. In this study, an in vitro model of ARDS and PF caused by SARS-CoV-2 was established in MH-S, THP-1, and MRC-5 cells using pseudo-SARS-CoV-2 (PSCV). Expression of proinflammatory cytokines (IL-6, IL-1β, and TNF-α) and HIF-1α was increased in PSCV-infected MH-S and THP-1 cells, ARDS model, consistent with other profiling data in SARS-CoV-2-infected patients have been reported. Hypoxia-inducible factor-1 alpha (HIF-1α) siRNA and cobalt chloride were tested using this in vitro model. Furthermore, apigetrin, a glycoside bioactive dietary flavonoid derived from several plants, including Crataegus pinnatifida, which is reported to be a HIF-1α inhibitor, was tested in this in vitro model [1]. Apigetrin significantly reduced the increased inflammatory cytokine (IL-6, IL-1β, and TNF-α) expression and secretion by PSCV in MH-S and THP-1 cells. Apigetrin inhibited the binding of the SARS-CoV-2 spike protein RBD to the ACE2 protein. An in vitro model of PF induced by SARS-CoV-2 was produced using a conditioned medium of THP-1 and MH-S cells that were PSCV-infected (CMPSCV) into MRC-5 cells. In a PF model, CMPSCV treatment of THP-1 and MH-S cells increased cell growth, migration, and collagen synthesis in MRC-5 cells. In contrast, apigetrin suppressed the increase in cell growth, migration, and collagen synthesis induced by CMPSCV in THP-1 and MH-S MRC-5 cells. Also, compared to control, fibrosis-related proteins (CTGF, COLA1, α-SMA, and HIF-1α) levels were over two-fold higher in CMPSV-treated MRC-5 cells. Apigetrin decreased protein levels in CMPSCV-treated MRC-5 cells. Thus, our data suggest that hypoxia-inducible factor-1 alpha (HIF-1α) might be a novel target for SARS-CoV-2 sequela therapies and apigetrin, representative of HIF-1alpha inhibitor, exerts anti-inflammatory and PF effects in PSCV-treated MH-S, THP-1, and CMPVSC-treated MRC-5 cells. These findings indicate that HIF-1α inhibition and apigetrin would have a potential value in controlling SARS-CoV-2-related diseases.

Beyond the Virus: QTc Interval Changes in COVID-19 Survivors (preprint)

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses angiotensin-converting enzyme-2 receptors on host cells to enter the cells. These receptors are expressed on heart muscle tissue and the tissues of other major organs, which supports the primary accepted theory for the direct cardiac cell injury of coronavirus disease 2019 (COVID-19) and the associated cardiorespiratory manifestations. The SARS-CoV-2 infection leads to unstable myocardial cell membranes due to hypoxia, myocarditis, myocardial ischemia, and abnormal host immune response. This is the main reason behind arrhythmia and electrocardiogram (ECG) changes during COVID-19. However, the specific effect on QTc after Covid 19 infection has not been studied well. Therefore, this study aimed to examine the association between post COVID-19 infection and QTc changes.Objectives: Examine the association between post COVID-19 infection and QTc changes.Materials and Methods: This is a case control study conducted on middle age of either sex involves 50 adult patients with post-COVID-19 infections (eight were defaulted from the study because they were not cooperative), 23 females and 19 males with mean age (36.98 ± 12.2 years) who were non-vaccinated against Covid 19 after one month to two years of an acute episode of COVID-19 (confirmed by positive real-time reverse-transcription polymerase chain reaction (RT-PCR)) test according to the World Health Organization (WHO) selected randomly from those attending to the adult Holter and Echocardiography lab in Al-Zahraa Hospital/ Al-Hussein Medical City/ Karbala Province after being referred by Internist during the period from the 12th of October 2022 to the end of January 2024 and divided in to three groups : non hospitalize, hospitalize and admitted to intensive care while control group consisted of 40 healthy persons 23 females and 17 males with mean age (33.28 ± 9.58 years), whom referred by Internist for ECG with no Hx of the previous infection of covid 19. All of them have electrocardiographic evaluation by taking ECG.Conclusion That post COVID-19 patients had prolonged QT and QTc intervals increase the risk for cardiac arrhythmias.

Neuroleptic malignant syndrome in a patient with COVID-19 and the possible role of SARS-CoV-2 in its manifestation. Case report and overview of published cases (preprint)

Background: The manifestationof severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is more complex than that of pulmonary infection, and neuropsychiatric symptoms play a role in this complexity. In this paper, we present the case of a 29-year-old schizophrenic patient who suffered from neuroleptic malignant syndrome (NMS) that developed during coronavirus disease 2019 (COVID-19) infection, with an emphasis on the possible connection between these two conditions. Additionally, we provide an overview of published NMS cases in patients with COVID-19 or after vaccination against SARS-CoV-2. Case presentation: A 29-year-old patient treated for schizophrenia was admitted to the hospital for agitation and aggressivity; shortly after arrival at the hospital, laryngospasm and hypoxia occurred. The patient tested positive for SARS-CoV-2, and later, he developed pneumonia. After continuing restlessness, haloperidol was administered, and a few days later, neuroleptic malignant syndrome occurred. He was treated with bromocriptine and recovered. Conclusions: As SARS-CoV-2 is known to interact with angiotensin-converting enzyme 2 and DOPA-decarboxylase is known to be coexpressed with this receptor, we hypothesized that COVID-19 infection might playa substantial role in the development of NMS.

Biological Effects of Corticosteroids on Pneumococcal Pneumonia in Mice and Humans (preprint)

Background: Streptococcus pneumoniae is the most common bacterial cause of community acquired pneumonia and the acute respiratory distress syndrome (ARDS). Some clinical trials have demonstrated a beneficial effect of corticosteroid therapy in community acquired pneumonia, COVID-19, and ARDS, but the mechanisms of this benefit remain unclear. The objective of this study was to investigate the effects of corticosteroids on the pulmonary biology of pneumococcal pneumonia in an observational cohort of mechanically ventilated patients and in a mouse model of bacterial pneumonia with Streptococcus pneumoniae. Methods: We studied gene expression with lower respiratory tract transcriptomes from a cohort of mechanically ventilated patients and in mice. We also carried out comprehensive physiologic, biochemical, and histological analyses in mice to identify the mechanisms of lung injury in Streptococcus pneumoniae with and without adjunctive steroid therapy. Results: Transcriptomic analysis identified pleiotropic effects of steroid therapy on the lower respiratory tract in critically ill patients with pneumococcal pneumonia, findings that were reproducible in mice. In mice with pneumonia, dexamethasone in combination with ceftriaxone reduced (1) pulmonary edema formation, (2) alveolar protein permeability, (3) proinflammatory cytokine release, (4) histopathologic lung injury score, and (5) hypoxemia but did not increase bacterial burden. Conclusions: The gene expression studies in patients and in the mice support the clinical relevance of the mouse studies, which replicate several features of pneumococcal pneumonia and steroid therapy in humans. In combination with appropriate antibiotic therapy in mice, treatment of pneumococcal pneumonia with steroid therapy reduced hypoxemia, pulmonary edema, lung permeability, and histologic criteria of lung injury, and also altered inflammatory responses at the protein and gene expression level. The results from these studies provide evidence for the mechanisms that may explain the beneficial effects of glucocorticoid therapy in patients with community acquired pneumonia from Streptococcus Pneumoniae.

Impact of mechanical power on mortality in ventilated critically ill patients. Retrospective study with continuous real-life data (preprint)

Background Over the past decade, numerous studies on potential factors contributing to ventilation-induced lung injury have been carried out. Mechanical power has been pointed out as the parameter that encloses all ventilation-induced lung injury-contributing factors. However, studies conducted to date provide data regarding mechanical power during the early hours of mechanical ventilation that may not correspond to the real scenario. Methods Retrospective observational study conducted at a single center in Spain. Patients admitted to the intensive care unit, > o = 18 years of age, and ventilated for over 24 hours were included. We extracted the mechanical power values throughtout the entire mechanical ventilation period from the clinical information system every two minutes. First, we calculate the cutoff-point for mechanical power beyond which there was a greater change in the probability of death. After, the sum of time values above the safe cut-off point was calculated to obtain the value in hours. We analyzed if the number of hours the patient was under ventilation with a mechanical power above the safe threshold was associated with mortality, invasive mechanical ventilation days, and intensive care unit length of stay. We repeated the analysis in different subgroups based on the degree of hypoxemia and in patients with SARS CoV-2 pneumonia. Results The cut-off point of mechanical power at with there is a higher increase in mortality was 18J/min. The greater the number or hours patients were under mechanical power > 18 J/min the higher the mortality in all the study population, in patients with SARS CoV-2 pneumonia and in mild to moderate hyopoxemic respiratory failure. The risk of death inceases 0.1% for each our with mechanical power exceeding 18 J/min. The number of hours with mechanical power > 18 J/min also affected the days of invasive mechanical ventilation and intensive care unit length of stay. Conclusions Continuous monitoring of mechanical power using an automated clinical information system shows that the number of hours with mechanical power > 18 J/min increases mortality in critically ill patients.

HIF-1α is Associated with Improved Survival in ARDS due to COVID-19: A Prospective Study (preprint)

Background Acute respiratory distress syndrome(ARDS) due to COVID-19 is accompanied by severe hypoxemia and hyperinflammation. Hypoxia-inducible factor(HIF) pathway plays a fundamental role in detecting hypoxia and developing appropriate responses. The epidemiological report claimed a lower rate of disease in the population living at high altitudes and hypothesized that adaptation to hypoxia might be advantageous for SARS-CoV-2 infection. This study was designed to examine the frequency of polymorphisms in the HIF-1α and PHD2(prolyl hydroxylase domain 2) genes, which are involved in the adaptation to hypoxia, and the relationship of existing polymorphisms with survival in the ARDS clinic developed due to COVID-19. Methods The study included 297 patients who developed ARDS due to COVID-19 infection and were admitted to the tertiary intensive care unit. Age, gender, hospitalization diagnosis, arterial blood pressure, heart rate, APACHEII score, SOFA laboratory parameters during hospitalization, vasopressor, dialysis and mechanical ventilation need during treatment, length of hospital stay, and 30-day mortality status were recorded. DNA was isolated from the blood samples by spin colon method with the QIAamp DNA MiniKit (Cat.No.51106, QIAGEN, Germany). Results Patients were divided into 3 groups according to their Hypoxia Inducible Factor-1α (C/T SNP [11549465]) genotypes. Frequencies were 71.13% for the homozygous CC genotype, 26.4% heterozygous CT genotype, and 2.36% for the homozygous TT genotype. Median age (p=0.631), APACHE II (p=0.205), and SOFA (p=0.077) scores were similar in all three groups. However, the need for dialysis, mechanical ventilation, and vasopressor was less in the homozygous TT-genotype group than in the other groups (p<0.05). The mortality rate was also lower in this group compared to other groups (p<0.05). PND2 (C/T SNP [480902] and [516651]) polymorphism, clinical and laboratory features were similar in all groups. Moreover, 30-day mortality did not differ between the groups. Conclusion In conclusion, we revealed polymorphism in HIF-lα and PHD2 genes in ARDS patients due to COVID-19. The rate of HIF-lα polymorphism was 26.4% heterozygous CT-genotype and 2.36% for homozygous TT-genotype. 30-day mortality and adverse outcome (dialysis, vasopressor use, MV need) were significantly lower in TT homozygous. However, none of the polymorphisms in the PHD2 genes affected mortality and adverse outcome.

Deciphering Abnormal Platelet Subpopulations in Inflammatory Diseases through Machine Learning and Single-Cell Transcriptomics (preprint)

IntroductionThe transcriptional heterogeneity of activated platelets, play a significant role in contributing to negative outcomes in sepsis, COVID-19, and autoimmune diseases such as systemic lupus erythematosus (SLE). Despite this, our understanding of these heterogeneous platelet responses remains limited. In this study, we aim to investigate the diverse transcriptional profiles of activated platelets in these diseases, with the goal of deciphering this platelet heterogeneity for new therapeutic strategies to target abnormal and pathogenic platelet subtypes. Materials and methodsWe obtained the single cell transcriptional profiles of blood platelets from patients with COVID-19, sepsis, and SLE. Utilizing machine learning algorithms, Deep Neural Network (DNN) and eXtreme Gradient Boosting (XGB), we discerned the distinct transcriptomic signatures indicative of fatal versus survival clinical outcomes. Our methodological framework incorporated source data annotations and platelet markers and used SingleR and Seurat for detailed profiling. Additionally, we implemented Uniform Manifold Approximation and Projection (UMAP) for dimensionality reduction and visualization, aiding in the detection of various platelet subtypes and their correlation with disease status and patient outcomes. ResultsOur study identified distinct platelet subpopulations that are associated with disease severity. We demonstrated that alterations in platelet transcription patterns can exacerbate endotheliopathy, potentially heightening the risk of coagulation in fatal patients. Moreover, these changes can also influence lymphocyte function, indicating a more extensive role for platelets in inflammatory and immune responses. ConclusionsEnhanced transcriptional heterogeneity in activated platelets is linked to adverse outcomes in conditions such as sepsis, COVID-19, and autoimmune diseases. The discovery of these unique platelet subpopulations paves the way for innovative therapeutic strategies targeting platelet activation, which could potentially improve patient outcomes. Summary sentenceSingle-Cell RNA Sequencing Analysis of Platelets from COVID-19, Sepsis, and SLE Reveals Disease Signatures and Treatment Options to Prevent Patient Mortality. Graphical AbstractsO_LIThe platelet to T cell ratio proportion in PBMC was identified as the most potent predictor for distinguishing survivors from fatal patients, underscores the potential of this ratio as a prognostic biomarker. C_LIO_LIThe discovery of different platelet subgroups, especially active coagulation, hypoxic, and quiescent clusters, in fatal COVID-19 patients, indicates potential targeted treatment strategies. C_LIO_LIIn patients with severe and fatal conditions, we observed three key phenomena: the aggregation of platelets with monocytes, the amplification of endothelial dysfunction by platelets, and a decrease in lymphocyte activation and differentiation due to platelets. C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=197 SRC="FIGDIR/small/572680v1_ufig1.gif" ALT="Figure 1"> View larger version (64K): org.highwire.dtl.DTLVardef@141ca55org.highwire.dtl.DTLVardef@4ad1aborg.highwire.dtl.DTLVardef@b400forg.highwire.dtl.DTLVardef@9ad44e_HPS_FORMAT_FIGEXP M_FIG C_FIG

Heart rate variability analysis at admission in the ICU of Covid-19 patients cannot predict invasive mechanical ventilation need: a prospective study (preprint)

PURPOSE: cardiovascular response to stress (such as hypoxemia) is mediated by the autonomic nervous system (ANS) and heart rate variability is an important part of it. Neurotropism is an important feature of SARS-CoV-2 infection and clinical dissociation between hypoxemia and the cardiovascular response has been reported. We proposed that HRV could be used to identify, at admission in the intensive care unit (ICU), those patients who were going to need invasive mechanical ventilation (IMV) during their stay.  METHODS: We performed a prospective single-centre observational study analyzing adult patients admitted to ICU at Hospital Clínico San Carlos with respiratory failure due SARS-CoV-2 pneumonia but not under IMV. We recorded continuous EKG waveforms and obtained time and frequency domains and non-linear dynamics HRV metrics.  RESULTS: 47 patients were screened and 27 were finally analyzed. 15 (55.5%) of them required intubation and IMV. Heart rate was 80 beats/min in each group. HRV metrics were similar between groups in the time domain, frequency domain and after using nonlinear analysis. However, when comparing against literature control, Covid-19 patients admitted in the ICU had a diminished HRV but higher heart rates.  CONCLUSION: We found that HRV on ICU admission didn't discriminate patients requiring IMV. We found that Covid-19 patients had a diminished HRV although having higher heart rates than healthy literature controls.

Evidence associating neutrophilia, lung damage, hyperlactatemia, blood acidosis, impaired oxygen transport, and mortality in critically ill COVID-19 patients (preprint)

Background: COVID-19 severity and high in-hospital mortality are often associated with severe hypoxemia, hyperlactatemia, and acidosis. Since neutrophil numbers in severe COVID-19 can exceed 80% of the total circulating leukocytes and that they are massively recruited to infected lungs, we investigated whether metabolic acidosis mediated by the glycolytic neutrophils is associated with lung damage and impaired oxygen delivery in critically ill patients. Methods: Based on prospective mortality outcome, 102 critically ill-hospitalized COVID-19 patients were divided into two groups: ICU-Survivors (ICU-S, n=36) and ICU-Non-survivors (ICU-NS, n=66). Blood samples were collected from patients and control subjects to explore correlations between neutrophil counts, lung damage, glycolysis, blood lactate, blood pH, hemoglobin oxygen saturation, and mortality outcome. We also interrogated isolated neutrophils for glycolytic activities and for apoptosis using high-throughput fluorescence imaging complemented with transcriptomic analyses. Stratified survival analyses were conducted to estimate mortality risk associated with higher lactate among predefined subgroups. Results: Neutrophil counts were consistently higher in critically ill patients while exhibiting remarkably lower apoptosis. Transcriptomic analysis revealed miRNAs associated with downregulation of genes involved in neutrophils apoptosis. Both CT lung damage scores and neutrophil counts predicted mortality. Severinghaus fitting of hemoglobin oxygen saturation curve revealed a right-shift indicating lower oxygen capacity in non-survivors, which is consistent with lower blood-pH observed in the same group. Levels of blood lactate were increased in patients but significantly more in the ICU-NS relative to the control group. ROC analysis followed by Kaplan-Meyer survival analysis stratified to the obtained cut-off values showed that CT damage scores, neutrophil counts, and lactate levels are predictors of mortality within 15 days following blood collection. Conclusion: The current results implicate neutrophilia as a potential player in metabolic acidosis and deranged oxygen delivery associating SARS-CoV-2 infection thus contributing to mortality outcome.

Suffocation in asthma and COVID-19: Supplementation of inhaled corticosteroids with alkaline hydrogen peroxide as an alternative to ECMO (preprint)

Suffocation syndrome is the leading cause of hypoxia and mortality in the most common lung diseases, asthma and COVID-19. Inhaled corticosteroids (ICSs) have been shown to be the main-stay of critical care in these diseases. Meanwhile, mortality from strangulated hypoxia is highest in low-income countries because ICSs are not currently available to many patients. Warm alkaline hydrogen peroxide solutions (WAHPSs) have reportedly been invented in recent years to urgently turn thick sputum, mucus, pus, serous fluid, blood clots and many other biological masses con-taining the enzyme catalase into a fluffy oxygenated foam. It has been shown that the mechanism of action of WAHPSs consists in alkaline saponification of lipid and protein-lipid complexes of bi-ological masses and their transformation into oxygen foam, because hydrogen peroxide is urgently decomposed into water and oxygen gas under the action of the biological masses catalase enzyme At that excess oxygen is absorbed into blood through lungs and increases blood oxygen saturation. Based on the described mechanism of action of WAHPSs and the high availability of their ingre-dients, it is suggested that mortality from choking and hypoxia in asthma and COVID-19 can be reduced by combining ICSs with inhaled WAHPSs, especially in poor countries. The essence of the inventions underlying the formation of WAHPSs is given.

Follow-Up In Patients With Respiratory Disability After ARDS Related To COVID-19: A Systematic Review (preprint)

Introduction: Acute Respiratory Distress Syndrome (ARDS) is an acute inflammatory pulmonary process that leads to protein-rich, non-hydrostatic pulmonary edema, undesirable hypoxemia, and lung stiffness. Due to COVID-19, a significant proportion of people who will require hospitalization to treat COVID-19, between 15%-30%, will develop severe respiratory failure, ARDS, and an increased likelihood of intubation for mechanical respiratory support. Aim: To investigate the pulmonary function in COVID-19-related ARDS survivors after hospitalization. Methods: A search was performed on the Greek and international literature, as well as at the online Databases PubMed, Cochrane, Embase, and Google Scholar. Exclusion and integration criteria were set for the studies found, and a flow chart was created for the studies included. Results: Through the search, 352 articles were found matching the subject under study, and after further evaluation, four articles were included. The majority of the articles highlight that after ARDS occurs due to COVID-19, patients face impaired pulmonary function in combination with other physical and psychological symptoms like weakness, anxiety, depression, and generalized functional disability. Conclusions: It is a fact that COVID-19 disease, in severe form and following the need for hospitalization due to the development of ARDS, results in an increased likelihood of prolonged occurrence of some symptoms of impaired respiratory function. Impaired CO2 diffusion is observed in the majority of studies as well as impaired respiratory function regarding prolonged imaging findings and impaired physical function. Keywords: ARDS, SARS-CoV-2, ICU, COVID-19, follow up, respiratory function

Effects of COVID-19 infection in patients with autoimmune pulmonary alveolar proteinosis: a single-center study (preprint)

Background:Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare interstitial lung disease. COVID-19 is associated with worse prognosis in previous lung diseases patients. But the prognosis of aPAP patients after infection with COVID-19 is unclear. In December 2022, China experienced a large-scale outbreak of Omicron variant of the SARS-CoV-2. In this study, we aim to explore the clinical outcomes of aPAP patients infected with COVID-19. Results: A total of 39 aPAP patients were included in this study. 30.77% patients had a decrease in oxygen saturation after COVID-19 infection. We compared the two groups of patients with or without decreased oxygen saturation after COVID-19 infection and found that patients who had previous oxygen therapy (decreased oxygen saturation vs. non decreased oxygen saturation: 6/12 vs. 4/27, P = 0.043), with lower baseline arterial oxygen partial pressure (74.50 ± 13.61 mmHg vs. 86.49 ± 11.92 mmHg, P = 0.009), lower baseline DLCO/VA% [77.0 (74.3, 93.6) % vs. 89.5 (78.2, 97.4) %, P = 0.036], shorter baseline 6MWD [464 (406, 538) m vs. 532 (470, 575) m, P = 0.028], higher disease severity score (P = 0.017), were more likely to have decreased oxygen saturation after COVID-19 infection. Conclusion: aPAP patients with poor baseline respiration have a higher probability of hypoxia after COVID-19 infection, but fatal events were rare.

Sports despite masks: No negative effects of FFP2 face masks on cardiopulmonary exercise capacity in children (preprint)

Introduction: Face masks were recognized as one of the most effective ways for preventing the spread of the COVID-19-virus in adults, the benefits of wearing those were extended to children and adolescents and led to limited physical education (PE) lessons or cancellation of them. This further decreased the amount of physical activity available to children and adolescents during the pandemic. However, there is little published data on the potential adverse effects on wearing the most effective and partially mandatory FFP2/N95 face-masks during PE or physical activity (PA) in this age. Even though the pandemic has been declared as passed by the WHO, the rise of a new pandemic and thus the use of face-masks for limiting its spread is inevitable, so we need to be prepared in a better way for alternative options to lockdown and limitation of PA in such a scenario.Material and Methods 20 healthy children aged 8–10 years performed two identical cardiopulmonary exercise tests as an incremental step test on a treadmill within an interval of two weeks, one time without wearing a protective mask and one time wearing a FFP2 mask. The cardiopulmonary exercise parameter and especially the endexpiratory gas exchange for oxygen and carbon dioxide (petO2 and petCO2) were documented for each step, at rest and 1 minute after reaching physical exhaustion.Results 12 boys (mean age 8.5 ± 1.4 years) and 8 girls (mean age 8.8 ± 1.4 years) showed no adverse events until maximal exertion. The mean parameters measured at peak exercise did not differ significantly between both examinations (mean Peak VO2 = 42.7 ± 9.5 vs 47.8 ± 12.9 ml/min/kg, mean O2pulse 7.84 ± 1.9 ml/min vs. 6.89 ± 1.8, mean VE/VCO2slope 33.4 ± 5.9 vs. 34.0 ± 5.3). The most significant difference was the respiratory exchange rate (RER, 1.01 ± 0.08 vs 0.95 ± 0.08). The measured respiratory gases (end tidal O2 and CO2) decreased respectively increased significantly into nearly each step wearing an additional FFP2-mask without reaching levels of hypercapnia or hypoxia.Conclusion In this study, no significant differences of the cardiorespiratory function at peak exercise could be discerned when wearing a FFP2/N95 face mask. While the end-tidal values for CO2 increased significantly and the end-tidal values for O2 decreased significantly, these values did never reach pathological levels. Furthermore, the children terminated the exercise at a lower RER and heart rate (HR) suggesting a subconscious awareness of the higher strain. Since the detrimental effects of limiting sports during the pandemic are well documented, stopping PE lessons altogether because of the minor physiological effects wearing these masks instead of simply stopping pushing children to perform at their best seems premature and should be reconsidered in the future.

HCG18, LEF1AS1 and lncCEACAM21 as biomarkers of disease severity in the Peripheral Blood Mononuclear Cells of COVID-19 patients (preprint)

Background Even after 3 years from SARS-CoV-2 identification, COVID-19 is still a persistent and dangerous global infectious disease. Significant improvements in our understanding of the disease pathophysiology have now been achieved. Nonetheless, reliable and accurate biomarkers for the early stratification of COVID-19 severity are still lacking. Long noncoding RNAs (LncRNAs) are ncRNAs longer than 200 nucleotides, regulating the transcription and translation of protein‐coding genes and they can be found in the peripheral blood, thus holding a promising biomarker potential. Specifically, peripheral blood mononuclear cells (PBMCs) have emerged as a source of indirect biomarkers mirroring the conditions of tissues: they include monocytes, B and T lymphocytes, and natural killer T cells (NKT), being highly informative for immune-related events. Methods We profiled by RNA-Sequencing a panel of 2,906 lncRNAs to investigate their modulation in PBMCs of a pilot group of COVID-19 patients, followed by qPCR validation in 111 hospitalized COVID-19 patients. Results The levels of four lncRNAs were found to be decreased in association with COVID-19 mortality and disease severity: HLA Complex Group 18-242 and -244 (HCG18-242 and HCG18-244), Lymphoid Enhancer Binding Factor 1-antisense 1 (LEF1-AS1) and lncCEACAM21 (i.e. ENST00000601116.5, a lncRNA in the CEACAM21 locus). Interestingly, these deregulations were confirmed in an independent patient group of hospitalized patients and by the re-analysis of publicly available single-cell transcriptome datasets. The identified lncRNAs were expressed in all of the PBMC cell types and inversely correlated with the neutrophil/lymphocyte ratio (NLR), an inflammatory marker. In vitro, the expression of LEF1-AS1 and lncCEACAM21 was decreased upon THP-1 monocytes exposure to a relevant stimulus, hypoxia. Conclusion The identified COVID-19-lncRNAs are proposed as potential innovative biomarkers of COVID-19 severity and mortality.

Oximetry at admission as a predictor of tomographic and functional impairment after 3-6 months in hospitalized patients with COVID-19.

OBJECTIVE: To investigate characteristics that may be associated with radiologic and functional findings following discharge in patients with severe coronavirus disease 2019 (COVID-19). METHODS: This single-center, prospective, observational cohort study comprised patients aged >18 years who were hospitalized with COVID-19 pneumonia, between May and October 2020. After 3 to 6 months of discharge, patients were clinically evaluated and underwent spirometry, a 6-minute walk test (6MWT), and chest computed tomography (CT). Statistical analysis was performed using association and correlation tests. RESULTS: A total of 134 patients were included (25/114 [22%] were admitted with severe hypoxemia). On the follow-up chest CT, 29/92 (32%) had no abnormalities, regardless of the severity of the initial involvement, and the mean 6MWT distance was 447 m. Patients with desaturation on admission had an increased risk of remaining CT abnormalities: patients with SpO2 between 88 and 92% had a 4.0-fold risk, and those with SpO2 < 88% had a 6.2-fold risk. The group with SpO2 < 88% also walked shorter distances than patients with SpO2 between 88 and 92%. CONCLUSION: Initial hypoxemia was found to be a good predictor of persistent radiological abnormalities in follow-up and was associated with low performance in 6MWT.

Chronic airway epithelial hypoxia exacerbates injury in muco-obstructive lung disease through mucus hyperconcentration.

Unlike solid organs, human airway epithelia derive their oxygen from inspired air rather than the vasculature. Many pulmonary diseases are associated with intraluminal airway obstruction caused by aspirated foreign bodies, virus infection, tumors, or mucus plugs intrinsic to airway disease, including cystic fibrosis (CF). Consistent with requirements for luminal O2, airway epithelia surrounding mucus plugs in chronic obstructive pulmonary disease (COPD) lungs are hypoxic. Despite these observations, the effects of chronic hypoxia (CH) on airway epithelial host defense functions relevant to pulmonary disease have not been investigated. Molecular characterization of resected human lungs from individuals with a spectrum of muco-obstructive lung diseases (MOLDs) or COVID-19 identified molecular features of chronic hypoxia, including increased EGLN3 expression, in epithelia lining mucus-obstructed airways. In vitro experiments using cultured chronically hypoxic airway epithelia revealed conversion to a glycolytic metabolic state with maintenance of cellular architecture. Chronically hypoxic airway epithelia unexpectedly exhibited increased MUC5B mucin production and increased transepithelial Na+ and fluid absorption mediated by HIF1α/HIF2α-dependent up-regulation of ß and γENaC (epithelial Na+ channel) subunit expression. The combination of increased Na+ absorption and MUC5B production generated hyperconcentrated mucus predicted to perpetuate obstruction. Single-cell and bulk RNA sequencing analyses of chronically hypoxic cultured airway epithelia revealed transcriptional changes involved in airway wall remodeling, destruction, and angiogenesis. These results were confirmed by RNA-in situ hybridization studies of lungs from individuals with MOLD. Our data suggest that chronic airway epithelial hypoxia may be central to the pathogenesis of persistent mucus accumulation in MOLDs and associated airway wall damage.

Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.