Browsing by Author "Davis, Michael D."
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Item 2020 Year in Review: Pharmacologic Treatments for COVID-19(2021-04) Saunders, Jessica L.; Davis, Michael D.; Pediatrics, School of MedicineCOVID-19, caused by SARS-CoV-2 infection, has led to a pandemic of acute respiratory illness. Pharmacologic treatments for COVID-19 have included treatments targeting infection prevention, prevention of viral replication, reducing inflammation and managing symptoms of respiratory failure caused by the disease. This is a review of key pharmacologic treatments for COVID-19 based on peer-reviewed articles from 2020.Item Antigen stasis and airway nitrosative stress in human primary ciliary dyskinesia(American Physiological Society, 2024) Gaston, Benjamin; Smith, Laura A.; Davis, Michael D.; Saunders, Jessica; Daniels, Ivana; Horani, Amjad; Brody, Steven L.; Giddings, Olivia; Zhao, Yi; Marozkina, Nadzeya; Pediatrics, School of MedicineNasal nitric oxide (nNO) is low in most patients with primary ciliary dyskinesia (PCD). Decreased ciliary motion could lead to antigen stasis, increasing oxidant production and NO oxidation in the airways. This could both decrease gas phase NO and increase nitrosative stress. We studied primary airway epithelial cells from healthy controls (HCs) and patients with PCD with several different genotypes. We measured antigen clearance in fenestrated membranes exposed apically to the fluorescently labeled antigen Dermatophagoides pteronyssinus (Derp1-f). We immunoblotted for 3-nitrotyrosine (3-NT) and for oxidative response enzymes. We measured headspace NO above primary airway cells without and with a PCD-causing genotype. We measured nNO and exhaled breath condensate (EBC) H2O2 in vivo. Apical Derp1-f was cleared from HC better than from PCD cells. DUOX1 expression was lower in HC than in PCD cells at baseline and after 24-h Derp1-f exposure. HC cells had less 3-NT and NO3- than PCD cells. However, NO consumption by HC cells was less than that by PCD cells; NO loss was prevented by superoxide dismutase (SOD) and by apocynin. nNO was higher in HCs than in patients with PCD. EBC H2O2 was lower in HC than in patients with PCD. The PCD airway epithelium does not optimally clear antigens and is subject to oxidative and nitrosative stress. Oxidation associated with antigen stasis could represent a therapeutic target in PCD, one with convenient monitoring biomarkers. NEW & NOTEWORTHY: The PCD airway epithelium does not optimally clear antigens, and antigen exposure can lead to NO oxidation and nitrosative stress. Oxidation caused by antigen stasis could represent a therapeutic target in PCD, and there are convenient monitoring biomarkers.Item Benefits of Airway Androgen Receptor Expression in Human Asthma(American Thoracic Society, 2021) Zein, Joe G.; McManus, Jeffrey M.; Sharifi, Nima; Erzurum, Serpil C.; Marozkina, Nadzeya; Lahm, Timothy; Giddings, Olivia; Davis, Michael D.; DeBoer, Mark D.; Comhair, Suzy A.; Bazeley, Peter; Kim, Hyun Jo; Busse, William; Calhoun, William; Castro, Mario; Chung, Kian Fan; Fahy, John V.; Israel, Elliot; Jarjour, Nizar N.; Levy, Bruce D.; Mauger, David T.; Moore, Wendy C.; Ortega, Victor E.; Peters, Michael; Bleecker, Eugene R.; Meyers, Deborah A.; Zhao, Yi; Wenzel, Sally E.; Gaston, Benjamin; Biostatistics, School of Public HealthRationale: Androgens are potentially beneficial in asthma, but AR (androgen receptor) has not been studied in human airways. Objectives: To measure whether AR and its ligands are associated with human asthma outcomes. Methods: We compared the effects of AR expression on lung function, symptom scores, and fractional exhaled nitric oxide (FeNO) in adults enrolled in SARP (Severe Asthma Research Program). The impact of sex and of androgens on asthma outcomes was also evaluated in the SARP with validation studies in the Cleveland Clinic Health System and the NHANES (U.S. National Health and Nutrition Examination Survey).Measurements and Main Results: In SARP (n = 128), AR gene expression from bronchoscopic epithelial brushings was positively associated with both FEV1/FVC ratio (R2 = 0.135, P = 0.0002) and the total Asthma Quality of Life Questionnaire score (R2 = 0.056, P = 0.016) and was negatively associated with FeNO (R2 = 0.178, P = 9.8 × 10-6) and NOS2 (nitric oxide synthase gene) expression (R2 = 0.281, P = 1.2 × 10-10). In SARP (n = 1,659), the Cleveland Clinic Health System (n = 32,527), and the NHANES (n = 2,629), women had more asthma exacerbations and emergency department visits than men. The levels of the AR ligand precursor dehydroepiandrosterone sulfate correlated positively with the FEV1 in both women and men. Conclusions: Higher bronchial AR expression and higher androgen levels are associated with better lung function, fewer symptoms, and a lower FeNO in human asthma. The role of androgens should be considered in asthma management.Item Blood Biomarkers for Detection of Brain Injury in COVID-19 Patients(Mary Ann Liebert, 2021) DeKosky, Steven T.; Kochanek, Patrick M.; Valadka, Alex B.; Clark, Robert S. B.; Chou, Sherry H. Y.; Au, Alicia K.; Horvat, Christopher; Jha, Ruchira M.; Mannix, Rebekah; Wisniewski, Stephen R.; Wintermark, Max; Rowell, Susan E.; Welch, Robert D.; Lewis, Lawrence; House, Stacey; Tanzi, Rudolph E.; Smith, Darci R.; Vittor, Amy Y.; Denslow, Nancy D.; Davis, Michael D.; Glushakova, Olena Y.; Hayes, Ronald L.; Pediatrics, School of MedicineThe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus attacks multiple organs of coronavirus disease 2019 (COVID-19) patients, including the brain. There are worldwide descriptions of neurological deficits in COVID-19 patients. Central nervous system (CNS) symptoms can be present early in the course of the disease. As many as 55% of hospitalized COVID-19 patients have been reported to have neurological disturbances three months after infection by SARS-CoV-2. The mutability of the SARS-COV-2 virus and its potential to directly affect the CNS highlight the urgency of developing technology to diagnose, manage, and treat brain injury in COVID-19 patients. The pathobiology of CNS infection by SARS-CoV-2 and the associated neurological sequelae of this infection remain poorly understood. In this review, we outline the rationale for the use of blood biomarkers (BBs) for diagnosis of brain injury in COVID-19 patients, the research needed to incorporate their use into clinical practice, and the improvements in patient management and outcomes that can result. BBs of brain injury could potentially provide tools for detection of brain injury in COVID-19 patients. Elevations of BBs have been reported in cerebrospinal fluid (CSF) and blood of COVID-19 patients. BB proteins have been analyzed in CSF to detect CNS involvement in patients with infectious diseases, including human immunodeficiency virus and tuberculous meningitis. BBs are approved by the U.S. Food and Drug Administration for diagnosis of mild versus moderate traumatic brain injury and have identified brain injury after stroke, cardiac arrest, hypoxia, and epilepsy. BBs, integrated with other diagnostic tools, could enhance understanding of viral mechanisms of brain injury, predict severity of neurological deficits, guide triage of patients and assignment to appropriate medical pathways, and assess efficacy of therapeutic interventions in COVID-19 patients.Item Effects of pH alteration on respiratory syncytial virus in human airway epithelial cells(European Respiratory Society, 2023-07-03) Saunders, Jessica L.; Daniels, Ivana A.; Edwards, Taiya L.; Relich, Ryan F.; Zhao, Yi; Smith, Laura A.; Gaston, Benjamin M.; Davis, Michael D.; Pediatrics, School of MedicineBackground: Respiratory syncytial virus (RSV) is a leading cause of respiratory distress and hospitalisation in the paediatric population. Low airway surface pH impairs antimicrobial host defence and worsens airway inflammation. Inhaled Optate safely raises airway surface pH in humans and raises intracellular pH in primary human airway epithelial cells (HAECs) in vitro. We aimed to determine whether raising intracellular pH with Optate would decrease infection and replication of RSV in primary HAECs. Methods: We cultured HAECs from healthy subjects in both air-liquid interface and submerged conditions. We infected HAECs with green fluorescent protein-labelled RSV (GFP-RSV; multiplicity of infection=1) and treated them with Optate or PBS control. We collected supernatant after a 4-h incubation and then every 24 h. We used fluorescence intensity, fluorescent particle counts, plaque assays, Western blots and ELISA to quantitate infection. Results: In submerged culture, fluorescence intensity decreased in Optate-treated cells (48 h p=0.0174, 72 h p≤0.001). Similarly, Optate treatment resulted in decreased fluorescent particle count (48 h p=0.0178, 72 h p=0.0019) and plaque-forming units (48 h p=0.0011, 72 h p=0.0148) from cell culture supernatant. In differentiated HAECs cultured at ALI, Optate treatment decreased fluorescence intensity (p≤0.01), GFP via Western blot and ELISA (p<0.0001), and RSV-fusion protein via ELISA (p=0.001). Additionally, RSV infection decreased as Optate concentration increased in a dose-dependent manner (p<0.001). Conclusions: Optate inhibits RSV infection in primary HAECs in a dose-dependent manner. These findings suggest that Optate may have potential as an inhaled therapeutic for patients with RSV.Item Exhaled breath condensate biomarkers in critically ill, mechanically ventilated patients(IOP, 2020-11-12) Davis, Michael D.; Winters, Brett R.; Madden, Michael C.; Pleil, Joachim D.; Sessler, Curtis N.; Wallace, M. Ariel Geer; Ward-Caviness, Cavin K.; Montpetit, Alison J.; Pediatrics, School of MedicinePneumonia is a significant risk for critically ill, mechanically ventilated (CIMV) patients. Diagnosis of pneumonia generally requires a combination of clinician-guided diagnoses and clinical scoring systems. Exhaled breath condensate (EBC) can be safely collected non-invasively from CIMV patients. Hundreds of biomarkers in EBC are associated with acute disease states, including pneumonia. We evaluated cytokines in EBC from CIMV patients and hypothesized that these biomarkers would correlate with disease severity in pneumonia, sepsis, and death. EBC IL-2 levels were associated with chest radiograph severity scores (odds ratio = 1.68; 95% confidence interval = 1.09-2.60; P = 0.02). EBC TNF-α levels were also associated with pneumonia (odds ratio = 3.20; 95% confidence interval = 1.19-8.65; P = 0.02). The techniques and results from this study may be useful for all mechanically ventilated patients.Item Local Effects of Two Intravenous Formulations of Pulmonary Vasodilators on Airway Epithelium(AARC, 2020-10) Kuch, Bradley A.; Linssen, Rosalie; Yoshikawa, Hiroki; Smallwood, Craig D.; Davis, Michael D.; Pediatrics, School of MedicineBACKGROUND: Intravenous formulations of epoprostenol are frequently delivered via nebulizer to treat pulmonary hypertension in acutely ill patients. Although their efficacy as pulmonary vasodilators has been shown to be comparable to inhaled nitric oxide, the local effects of these formulations within the airways have not been determined. We hypothesized that the alkaline diluents of these compounds would lead to increased airway epithelial cell death and ciliary cessation. METHODS: Human bronchial epithelial cells were exposed to epoprostenol in glycine and arginine diluents or control fluid. Ciliary beat frequency, lactate dehydrogenase, and total RNA levels were measured before and after exposure. Results were compared between exposure and control groups. RESULTS: Ciliary beat frequency ceased immediately after exposure to epoprostenol with both diluents. Lactate dehydrogenase levels increased by 200% after exposure to epoprostenol and glycine diluent (P = .002). Total RNA levels were undetectable after exposure to epoprostenol and arginine, indicating complete cell death and lysis (P = .015). Ciliary beat frequency ceased after 30 s of exposure to epoprostenol and glycine (P = .008). There was no difference between cells exposed to epoprostenol and those exposed only to diluent. CONCLUSIONS: Exposure to intravenous formulations of epoprostenol in glycine and arginine caused increased cell death and ciliary cessation in bronchial epithelial cells. These findings suggest that undesired local effects may occur when these compounds are delivered as inhaled aerosols to patients.Item Methods to Detect Volatile Organic Compounds for Breath Biopsy Using Solid-Phase Microextraction and Gas Chromatography–Mass Spectrometry(MDPI, 2023-06-03) Schulz, Eray; Woollam, Mark; Grocki, Paul; Davis, Michael D.; Agarwal, Mangilal; Chemistry and Chemical Biology, School of ScienceVolatile organic compounds (VOCs) are byproducts from metabolic pathways that can be detected in exhaled breath and have been reported as biomarkers for different diseases. The gold standard for analysis is gas chromatography–mass spectrometry (GC–MS), which can be coupled with various sampling methods. The current study aims to develop and compare different methods for sampling and preconcentrating VOCs using solid-phase microextraction (SPME). An in-house sampling method, direct-breath SPME (DB–SPME), was developed to directly extract VOCs from breath using a SPME fiber. The method was optimized by exploring different SPME types, the overall exhalation volume, and breath fractionation. DB–SPME was quantitatively compared to two alternative methods involving the collection of breath in a Tedlar bag. In one method, VOCs were directly extracted from the Tedlar bag (Tedlar–SPME) and in the other, the VOCs were cryothermally transferred from the Tedlar bag to a headspace vial (cryotransfer). The methods were verified and quantitatively compared using breath samples (n = 15 for each method respectively) analyzed by GC–MS quadrupole time-of-flight (QTOF) for compounds including but not limited to acetone, isoprene, toluene, limonene, and pinene. The cryotransfer method was the most sensitive, demonstrating the strongest signal for the majority of the VOCs detected in the exhaled breath samples. However, VOCs with low molecular weights, including acetone and isoprene, were detected with the highest sensitivity using the Tedlar–SPME. On the other hand, the DB–SPME was less sensitive, although it was rapid and had the lowest background GC–MS signal. Overall, the three breath-sampling methods can detect a wide variety of VOCs in breath. The cryotransfer method may be optimal when collecting a large number of samples using Tedlar bags, as it allows the long-term storage of VOCs at low temperatures (−80 °C), while Tedlar–SPME may be more effective when targeting relatively small VOCs. The DB-SPME method may be the most efficient when more immediate analyses and results are required.Item Somatic cell hemoglobin modulates nitrogen oxide metabolism in the human airway epithelium(Springer Nature, 2021-07-29) Marozkina, Nadzeya; Smith, Laura; Zhao, Yi; Zein, Joe; Chmiel, James F.; Kim, Jeeho; Kiselar, Janna; Davis, Michael D.; Cunningham, Rebekah S.; Randell, Scott H.; Gaston, Benjamin; Pediatrics, School of MedicineEndothelial hemoglobin (Hb)α regulates endothelial nitric oxide synthase (eNOS) biochemistry. We hypothesized that Hb could also be expressed and biochemically active in the ciliated human airway epithelium. Primary human airway epithelial cells, cultured at air–liquid interface (ALI), were obtained by clinical airway brushings or from explanted lungs. Human airway Hb mRNA data were from publically available databases; or from RT-PCR. Hb proteins were identified by immunoprecipitation, immunoblot, immunohistochemistry, immunofluorescence and liquid chromatography- mass spectrometry. Viral vectors were used to alter Hbβ expression. Heme and nitrogen oxides were measured colorimetrically. Hb mRNA was expressed in human ciliated epithelial cells. Heme proteins (Hbα, β, and δ) were detected in ALI cultures by several methods. Higher levels of airway epithelial Hbβ gene expression were associated with lower FEV1 in asthma. Both Hbβ knockdown and overexpression affected cell morphology. Hbβ and eNOS were apically colocalized. Binding heme with CO decreased extracellular accumulation of nitrogen oxides. Human airway epithelial cells express Hb. Higher levels of Hbβ gene expression were associated with airflow obstruction. Hbβ and eNOS were colocalized in ciliated cells, and heme affected oxidation of the NOS product. Epithelial Hb expression may be relevant to human airways diseases.Item The physics of human breathing: flow, timing, volume, and pressure parameters for normal, on-demand, and ventilator respiration(IOP, 2021-09-27) Pleil, Joachim D.; Wallace, M. Ariel Geer; Davis, Michael D.; Matty, Christopher M.; Pediatrics, School of MedicineNormal breathing for healthy humans is taken for granted; it occurs without conscious effort using ambient (1-atmosphere) pressure with 21% oxygen (O2) concentration. The body automatically adjusts for stress, exercise, altitude, and mild disease by increasing the volume and frequency of breathing. Longer term adaptations for exercise and altitude include increases in red blood cell counts and higher concentrations of capillaries in muscle tissue. When more challenging external environmental conditions or pulmonary illnesses exceed the capability for these adaptations, the human system requires technology to maintain sufficient ventilation to preserve life. On the environmental side there are two conditions to be addressed: toxicity of the surrounding atmosphere and changes in external pressure and O2concentration. On the medical side, mechanisms for assisting breathing include O2supplementation at ambient pressure, positive pressure/flow without additional O2, or a combination of both. This overview describes the various technologies applied to maintaining a safe breathing environment. Topics for environmental intervention include filter-based and flowing air-supply masks for toxic environments (occupational and laboratory protection), and on-demand gas supply systems for firefighters, self-contained underwater breathing apparatus divers, and altitude (high performance aircraft, spacecraft) applications. The topics for medical intervention include nasal cannula, continuous positive airway pressure, and medical ventilators. The primary purpose of this article is to provide a basic understanding of normal human breathing and the adaptation of breathing in different environments using available technologies.