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In the absence of infection, the pathophysiology of endotracheal tube-induced sore throat pain is unclear. Activated neutrophils release elastase, reactive oxygen species, and inflammatory cytokines known to contribute to neuropathic pain. Sterile tissue injury can cause the release of damage-associated molecular patterns such as mitochondrial DNA that promote neutrophil activation. We hypothesized that endotracheal tube-induced sore throat pain is linked to mitochondrial DNA-mediated neutrophil inflammation. A nonrandomized prospective survey for sore throat pain was conducted in 31 patients who required short-term intubation and had no evidence of upper airway infection. Patterns of neutrophil abundance, activation, and mitochondrial DNA levels were analyzed in tracheal lavage fluid following intubation and prior to extubation. Thirteen of 31 patients reported sore throat pain. Sore throat patients had high neutrophilia with elevated adhesion molecule and TLR9 expression and constitutive reactive oxygen species generation. Tracheal lavage fluid from sore throat patients accumulated mitochondrial DNA and stimulated neutrophils to release mediators associated with pain in a TLR9- and DNAse-dependent fashion. Endotracheal tube-induced sore throat is linked to the release of mitochondrial DNA and can drive TLR9-mediated inflammatory responses by neutrophils reported to cause pain. Mitigating the effects of cell-free mitochondrial DNA may prove beneficial for the prevention of endotracheal tube-mediated sore throat pain.

BackgroundThe most severe cases of Coronavirus-Disease-2019 (COVID-19) develop into Acute Respiratory Distress Syndrome (ARDS). It has been proposed that oxygenation may be inhibited by extracellular deoxyribonucleic acid (DNA) in the form of neutrophil extracellular traps (NETs). Dornase alfa (Pulmozyme, Genentech) is recombinant human deoxyribonuclease I that acts as a mucolytic by cleaving and degrading extracellular DNA. We performed a pilot study to evaluate the effects of dornase alfa in patients with ARDS secondary to COVID-19.MethodsWe performed a pilot, non-randomized, case-controlled clinical trial of inhaled dornase for patients who developed ARDS secondary to COVID-19 pneumonia.ResultsImprovement in arterial oxygen saturation to inhaled fraction of oxygen ratio (PaO2/FiO2) was noted in the treatment group compared to control at day 2 (95% CI, 2.96 to 95.66, P-value = 0.038), as well as in static lung compliance at days 3 through 5 (95% CI, 4.8 to 19.1 mL/cmH2O, 2.7 to 16.5 mL/cmH2O, and 5.3 to 19.2 mL/cmH2O, respectively). These effects were not sustained at 14 days. A reduction in bronchoalveolar lavage fluid (BALF) myeloperoxidase-DNA (DNA : MPO) complexes (95% CI, -14.7 to -1.32, P-value = 0.01) was observed after therapy with dornase alfa.ConclusionTreatment with dornase alfa was associated with improved oxygenation and decreased DNA : MPO complexes in BALF. The positive effects, however, were limited to the time of drug delivery. These data suggest that degradation of extracellular DNA associated with NETs or other structures by inhaled dornase alfa can be beneficial. We propose a more extensive clinical trial is warranted.Clinical Trial RegistrationClinicalTrials.gov, Identifier: NCT04402970.

Tracheitis secondary to placement of an endotracheal tube (ETT) is characterized by neutrophil accumulation in the tracheal lumen, which is generally associated with epithelial damage. Mitochondrial DNA (mtDNA), has been implicated in systemic inflammation and organ dysfunction following trauma; however, less is known about the effects of a foreign body on local trauma and tissue damage. We hypothesized that tracheal damage secondary to the ETT will result in local release of mtDNA at sufficient levels to induce TLR9 and NF‐κB activation. In a swine model we compared the differences between uncoated, and chloroquine (CQ) and N‐acetylcysteine (NAC) coated ETTs as measured by tracheal lavage fluids (TLF) over a period of 6 h. The swine model allowed us to recreate human conditions. ETT presence was characterized by neutrophil activation, necrosis, and release of proinflammatory cytokines mediated by TLR9/NF‐κB induction. Amelioration of the tracheal damage was observed in the CQ and NAC coated ETT group as shown in tracheal tissue specimens and TLF. The role of TLR9/NF‐κB dependent activity was confirmed by HEK‐Blue hTLR9 reporter cell line analysis after coincubation with TLF specimens with predetermined concentrations of NAC or CQ alone or TLR9 inhibitory oligodeoxynucleotide (iODN). These findings indicate that therapeutic interventions aimed at preventing mtDNA/TLR9/NF‐κB activity may have benefits in prevention of acute tracheal damage.

In the lungs of infected individuals, the downstream molecular signaling pathways induced by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are incompletely understood. Here, we describe and examine predictions of a model in which NOTCH may represent a central signaling axis in lung infection in Coronavirus Disease 2019 (COVID-19). A pathway involving NOTCH signaling, furin, ADAM17, and ACE2 may be capable of increasing SARS-CoV-2 viral entry and infection. NOTCH signaling can also upregulate IL-6 and pro-inflammatory mediators induced to hyperactivation in COVID-19. Furthermore, if NOTCH signaling fails to turn down properly and stays elevated, airway regeneration during lung healing can be inhibited—a process that may be at play in COVID-19. With specific NOTCH inhibitor drugs in development and clinical trials for other diseases being conducted, the roles of NOTCH in all of these processes central to both infection and healing merit contemplation if such drugs might be applied to COVID-19 patients.

Background SARS-CoV-2 virus is the cause of the current global pandemic and has affected more than 188 countries worldwide. Infection by the virus can have diverse clinical manifestations with one of the most severe clinical manifestation being respiratory failure and the development of acute respiratory distress syndrome. Clinical manifestations of acute respiratory distress syndrome secondary to SARS-CoV-2 are also diverse with a lack of diagnostic tools to distinguish between primary viral infection and secondary bacterial infections. Methods Single center, retrospective case-control study of bronchoalveolar lavage fluid cell counts, flow cytometry and culture results from mechanically ventilated patients with SARS-CoV-2 (COVID-19) pneumonia and acute respiratory distress syndrome. Results Neutrophils were the predominant cell type in bronchoalveolar fluid samples up to two weeks into mechanical ventilation. There also was a strong correlation between positive respiratory cultures and significant elevation in bronchoalveolar fluid neutrophil counts/percentages and serum c-reactive protein (CRP) levels. Absolute levels of T cell subtypes correlated with reduced lung compliance measurements. Conclusion Patients with SARS-CoV-2 and severe respiratory disease are at risk for secondary infections. In some COVID-19 patients, serum CRP and bronchoalveolar fluid neutrophils may be correlated with a secondary infection.

Bladder instrumentation engages the innate immune system via neutrophil activation, promoting inflammation and pain. Elevated levels of mitochondrial DNA (mtDNA) have been associated with tissue damage and organ dysfunction. We hypothesized that local bladder trauma induced by a Foley catheter (FC) will result in mtDNA release, migration of neutrophils into the bladder lumen, and activation of the Toll-like receptor 9 (TLR9) and nuclear factor kappa B (NF-κB) pathway leading to bladder tissue damage. We randomized 10 swine into two groups receiving uncoated, or chloroquine/N-Acetylcysteine (CQ/NAC)-coated FCs. Urine samples were analyzed for mtDNA activation of TLR9/NF-κB as demonstrated by indicators of neutrophil adhesion, migration, and activation. We found that uncoated FCs resulted in a unique active neutrophil phenotype that correlated with bladder epithelial injury, neutrophilia, necrosis, mtDNA release, TLR9/NF-κB activation, transcription and secretion of pro-inflammatory cytokines, and enhanced respiratory burst. In our study we observed that the high levels of mtDNA and elevated TLR9/NF-κB activity were ameliorated in the CQ/NAC-coated FC group. These findings suggest that post-migrated bladder luminal neutrophils are involved in local tissue damage and amelioration of the mtDNA/TLR9/NF-κB inflammatory axis may represent a therapeutic target to prevent inflammation, and bladder tissue injury.

RESULTS: Results showed significant reductions of encrustation on polyether PU and polyester PU compared to silicone (p-values < .0001) and similar levels of encrustation on polycarbonate PU compared to silicone (p-values < .510).CONCLUSIONS: This study showed how polycarbonate PU encrusted much more than polyether and polyester PU, though all three are called 'polyurethane.' Furthermore, results suggest polyester and polyether PU perform better than silicone in terms of encrustation resistance. Future work includes clinical trials to confirm results.Note: The first experiment was done before the submission deadline and the duplicate experiment was done after the submission deadline to confirm findings.