Airway Fluid Research Articles

RNA Sequencing Analysis of Monocytes Exposed to Airway Fluid From Children With Pediatric Acute Respiratory Distress Syndrome.

Monocytes are plastic cells that assume different polarization states that can either promote inflammation or tissue repair and inflammation resolution. Polarized monocytes are partially defined by their transcriptional profiles that are influenced by environmental stimuli. The airway monocyte response in pediatric acute respiratory distress syndrome (PARDS) is undefined. To identify differentially expressed genes and networks using a novel transcriptomic reporter assay with donor monocytes exposed to the airway fluid of intubated children with and at-risk for PARDS. To determine differences in gene expression at two time points using the donor monocyte assay exposed to airway fluid from intubated children with PARDS obtained 48-96 hours following initial tracheal aspirate sampling. In vitro pilot study carried out using airway fluid supernatant. Academic 40-bed PICU. Fifty-seven children: 44 children with PARDS and 13 children at-risk for PARDS. None. We performed bulk RNA sequencing using a transcriptomic reporter assay of monocytes exposed to airway fluid from intubated children to discover gene networks differentiating PARDS from at-risk for PARDS and those differentiating mild/moderate from severe PARDS. We also report differences in gene expression in children with PARDS 48-96 hours following initial tracheal aspirate sampling. We found that interleukin (IL)-10, IL-4, and IL-13, cytokine/chemokine signaling, and the senescence-associated secretory phenotype are upregulated in monocytes exposed to airway fluid from intubated children with PARDS compared with those at-risk for PARDS. Signaling by NOTCH, histone deacetylation/acetylation, DNA methylation, chromatin modifications (B-WICH complex), and RNA polymerase I transcription and its associated regulatory apparatus were upregulated in children with PARDS 48-96 hours following initial tracheal aspirate sampling. We identified gene networks important to the PARDS airway immune response using bulk RNA sequencing from a monocyte reporter assay that exposed monocytes to airway fluid from intubated children with and at-risk for PARDS. Mechanistic investigations are needed to validate our findings.

EPS9.08 A modelling framework for epithelial airway fluid and ion transport with multiple cell types: implications for success or failure in gene therapies for cystic fibrosis

EPS9.08 A modelling framework for epithelial airway fluid and ion transport with multiple cell types: implications for success or failure in gene therapies for cystic fibrosis

Adenylate cyclase 6 targets in Mucociliary Clearance

Background. Mucociliary clearance (MCC) is a frontline airway defense mechanism that relies on the appropriate interactions between the epithelium, ciliary beat frequency, and the quantity and quality of mucus. MCC is severely impaired in cystic fibrosis (CF) and drives lung function decline and ultimate respiratory failure and death. A great need remains to identify the key molecular players that regulate MCC in CF outside the scope of FDA approved CFTR therapy and to specifically target MCC dysfunction in CF using small molecules. Results. We discover a novel key role of cAMP-synthesizing enzyme Adenylate cyclase 6 (AC6) in MCC via (a) regulation of CFTR chloride channels in the secretory cells that generate airway surface liquid (ASL) component of MCC and (b) AC6 mediated regulation of ciliary beat frequency in the ciliated cells that is required for the mechanical clearance. Specific activators of AC6 (C20: Top candidate) were developed and improved MCC process ex vivo in CF explant tissues and cells. Together these mechanisms and small molecule approach that improve airway fluid balance and cilia function could be beneficial in CF and other respiratory diseases. Experimental Approach. We performed CFTR functional assessment in normal and CF patient derived airway epithelial cells by adapting patch-sequencing approach and using the specific activators of AC6. The effect of AC6 activators on MCC will be evaluated ex vivo in patient derived lung explant tissues , in vivo (micro-CT) in CF rat models and in vitro (ciliary beat frequency and bead flow measurements) in air-liquid interface airway epithelial cultures. Overall, these studies will be mechanistic and translational involving human disease specimens, animal models, drug development and computational analysis. Significance of the results. The proposed research can improve our understanding of epithelial biology and advance activators of AC6 as therapeutic agents to treat mucus clearance defects. These findings can be leveraged to modulate CFTR function and cilia-generate flow, presenting a potential therapeutic avenue for conditions that involve CFTR and cilia dysregulation associated with several respiratory diseases. National Institutes of Health (NIH) DK080834 and P30-DK117467 and HL147351 (to APN). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Preventable deaths in hospitalized trauma patients.

To study the preventable trauma deaths of hospitalized patients in the United Arab Emirates and to identify opportunities for improvement. We analyzed the Abu Dhabi Emirate Trauma Registry data of admitted patients who died in the emergency department or in hospital from 2014 to 2019. A panel of experts categorize the deaths into not preventable (NP), potentially preventable (PP), and definitely preventable (DP). A total of 405 deaths were included, and 82.7% were males. The majority (89.1%) were NP, occurring mainly in the emergency department (40.4%) and the intensive care unit (49.9%). The combined potentially preventable and preventable death rate was 10.9%. The median (Interquartile range) age of the DP was 57.5 (37-76) years, compared with 32 (24-42) and 34 (25-55) years for NP and PP, respectively (p=0.008). Most of the PP deaths occurred in the intensive care unit (55.6%), while the DP occurred mainly in the ward (50%). Falls accounted for 25% of PP and DP. Deficiencies in airway care, hemorrhage control, and fluid management were identified in 25%, 43.2% and 29.5% of the DP/PP deaths, respectively. Seventy-two percent of the Airway deficiencies occurred in the prehospital, while 34.1% of hemorrhage control deficiencies were in the emergency department. Fluid management deficiencies occurred in the emergency department and the operation theater. DP and PP deaths comprised 10.9% of the deaths. Most of the DP occurred in the emergency department and ward. Prehospital Airway and in-hospital hemorrhage and excessive fluid were the main areas for opportunities for improvement.

Select amino acids recover cytokine-altered ENaC function in human bronchial epithelial cells.

The airway epithelium plays a pivotal role in regulating mucosal immunity and inflammation. Epithelial barrier function, homeostasis of luminal fluid, and mucociliary clearance are major components of mucosal defense mechanisms. The epithelial sodium channel (ENaC) is one of the key players in controlling airway fluid volume and composition, and characteristic cytokines cause ENaC and barrier dysfunctions following pulmonary infections or allergic reactions. Given the limited understanding of the requisite duration and magnitude of cytokines to affect ENaC and barrier function, available treatment options for restoring normal ENaC activity are limited. Previous studies have demonstrated that distinct amino acids can modulate epithelial ion channel activities and barrier function in intestines and airways. Here, we have investigated the time- and concentration-dependent effect of representative cytokines for Th1- (IFN-γ and TNF-α), Th2- (IL-4 and IL-13), and Treg-mediated (TGF-β1) immune responses on ENaC activity and barrier function in human bronchial epithelial cells. When cells were exposed to Th1 and Treg cytokines, ENaC activity decreased gradually while barrier function remained largely unaffected. In contrast, Th2 cytokines had an immediate and profound inhibitory effect on ENaC activity that was subsequently followed by epithelial barrier disruption. These functional changes were associated with decreased membrane protein expression of α-, β-, and γ-ENaC, and decreased mRNA levels of β- and γ-ENaC. A proprietary blend of amino acids was developed based on their ability to prevent Th2 cytokine-induced ENaC dysfunction. Exposure to the select amino acids reversed the inhibitory effect of IL-13 on ENaC activity by increasing mRNA levels of β- and γ-ENaC, and protein expression of γ-ENaC. This study indicates the beneficial effect of select amino acids on ENaC activity in an in vitro setting of Th2-mediated inflammation suggesting these amino acids as a novel therapeutic approach for correcting this condition.

Liquid plug propagation in computer-controlled microfluidic airway-on-a-chip with semi-circular microchannels.

This paper introduces a two-inlet, one-outlet lung-on-a-chip device with semi-circular cross-section microchannels and computer-controlled fluidic switching that enables a broader systematic investigation of liquid plug dynamics in a manner relevant to the distal airways. A leak-proof bonding protocol for micro-milled devices facilitates channel bonding and culture of confluent primary small airway epithelial cells. Production of liquid plugs with computer-controlled inlet channel valving and just one outlet allows more stable long-term plug generation and propagation compared to previous designs. The system also captures both plug speed and length as well as pressure drop concurrently. In one demonstration, the system reproducibly generates surfactant-containing liquid plugs, a challenging process due to lower surface tension that makes the plug formation less stable. The addition of surfactant decreases the pressure required to initiate plug propagation, a potentially significant effect in diseases where surfactant in the airways is absent or dysfunctional. Next, the device recapitulates the effect of increasing fluid viscosity, a challenging analysis due to higher resistance of viscous fluids that makes plug formation and propagation more difficult particularly in airway-relevant length scales. Experimental results show that increased fluid viscosity decreases plug propagation speed for a given air flow rate. These findings are supplemented by computational modeling of viscous plug propagation that demonstrates increased plug propagation time, increased maximum wall shear stress, and greater pressure differentials in more viscous conditions of plug propagation. These results match physiology as mucus viscosity is increased in various obstructive lung diseases where it is known that respiratory mechanics can be compromised due to mucus plugging of the distal airways. Finally, experiments evaluate the effect of channel geometry on primary human small airway epithelial cell injury in this lung-on-a-chip. There is more injury in the middle of the channel relative to the edges highlighting the role of channel shape, a physiologically relevant parameter as airway cross-sectional geometry can also be non-circular. In sum, this paper describes a system that pushes the device limits with regards to the types of liquid plugs that can be stably generated for studies of distal airway fluid mechanical injury.

RNA Sequencing Analysis of CD4+ T Cells Exposed to Airway Fluid From Children With Pediatric Acute Respiratory Distress Syndrome.

To identify differentially expressed genes and networks using a novel transcriptomic reporter assay with donor CD4+ T cells exposed to the airway fluid of intubated children with mild versus severe PARDS. In vitro pilot study. Laboratory-based study using human airway fluid samples admitted to a 36-bed university-affiliated pediatric intensive care unit. Seven children with severe PARDS, nine children with mild PARDS, and four intubated children without lung injury as controls. None. We performed bulk RNA sequencing using a transcriptomic reporter assay of CD4+ T cells exposed to airway fluid from intubated children to discover gene networks differentiating severe from mild PARDS. We found that innate immunity pathways, type I (α and β), and type II (γ) interferon response and cytokine/chemokine signaling are downregulated in CD4+ T cells exposed to airway fluid from intubated children with severe PARDS compared with those with mild PARDS. We identified gene networks important to the PARDS airway immune response using bulk RNA sequencing from a novel CD4+ T-cell reporter assay that exposed CD4+ T cells to airway fluid from intubated children with severe and mild PARDS. These pathways will help drive mechanistic investigations into PARDS. Validation of our findings using this transcriptomic reporter assay strategy is needed.

WS05.02 A Phase-1 multiple ascending dose healthy volunteer study to evaluate the safety, tolerability, and pharmacokinetics of GDC-6988, a dry powder formulation of a selective inhaled potentiator of TMEM16A

Objectives: Cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulators are not indicated for ~10% of people with CF and may not fully restore CFTR function. GDC-6988 is a potent and selective potentiator of TMEM16A and is expected to enhance calcium-induced anion transport, increase airway fluid secretion, and promote mucus hydration and clearance. We previously reported outcomes in healthy volunteers with a nebulized formulation of GDC-6988. Here we present blinded outcomes from an ongoing Phase 1 study of a dry powder (DP) formulation of GDC-6988.

Further evidence of a type 2 inflammatory signature in chronic obstructive pulmonary disease or emphysema

BackgroundThere is increasing recognition of a type 2 (T2) inflammatory pattern in a subset of patients with chronic obstructive pulmonary disease (COPD) or emphysema, characterized by blood and airway eosinophilia. The mechanism underlying this is not well established. The recognition that CD125 (interleukin [IL]-5 receptor alpha) is expressed on some lung neutrophils and eosinophils in patients with asthma led us to speculate that CD125 may also be expressed on lung neutrophils in patients with COPD or emphysema. ObjectiveTo interrogate the expression of CD125 on lung neutrophils (and, when present, eosinophils) in patients with COPD/emphysema and identify a meaningful biomarker to predict neutrophil CD125 expression, including other markers of T2 inflammation. MethodsWe obtained blood and bronchoalveolar lavage (BAL) samples from patients with physician-diagnosed COPD/emphysema undergoing a clinically indicated bronchoscopy. ResultsWe found that a highly variable percentage of BAL neutrophils indeed expressed surface CD125 (0%-78.7%), with obvious clustering of CD125high and CD125low patterns. No correlation was found with clinical characteristics, blood or BAL eosinophil or neutrophil counts, BAL cytokines, or BAL eosinophil CD125 expression. ConclusionWe conclude that, similar to asthma, lung neutrophils from patients with COPD display interleukin-5 receptor alpha (CD125) on their surface. This along with the frequent presence of IL-4 and IL-5 in airway fluid further suggests a possible role of the T2 pathway in contributing to COPD severity. Trial RegistrationClinicalTrials.gov Identifier: NCT03984799

Combining Oxidative Stress Markers and Expression of Surfactant Protein A in Lungs in the Diagnosis of Seawater Drowning.

The diagnosis of seawater drowning (SWD) remains one of the most complex and contentious. It is one of the leading causes of unintentional death around the world. In most cases, the forensic pathologist must reach an accurate diagnosis from the autopsy findings and a series of complementary tests such as histopathological, biological, and chemical studies. Despite the lung being the most affected organ in death by submersion, there are few studies on this type of death's impact on this organ. The aim was to investigate human lung cadavers of forensic cases due to different causes of death, the concentration of the oxidative stress markers malondialdehyde (MDA) and γ-glutamyl-l-cysteinyl glycine (GSH), and the relationship with the expression of surfactant protein A (SP-A) to try to discriminate SWD from other types of causes of death. A total of 93 forensic autopsy cases were analyzed. Deaths were classified into three major groups based on the scene, cause of death, and autopsy findings (external foam, frothy fluid in airways, overlapping medial edges of the lungs): (a) drowning in seawater (n = 35), (b) other asphyxia (n = 33), such as hangings (n = 23), suffocations (n = 6), and strangulation (n = 4), and (c) other causes (n = 25), such as multiple suffocations. Oxidative stress markers (MDA and GSH) and the immunohistochemical expression of SP-A were determined in both lungs. MDA levels were statistically higher in both lungs in cases of SWD than in other causes of death (p = 0.023). Similarly, significantly higher levels of GSH were observed in SWD compared to the rest of the deaths (p = 0.002), which was more significant in the right lung. Higher immunohistochemical expression of SP-A was obtained in the cases of SWD than in the other causes of death, with higher levels in both lungs. The correlation analysis between the levels of oxidative stress (MDA and GSH) in the lung tissue and the expression level of SP-A showed positive and significant results in SWD, both in the alveolar membrane and the alveolar space. Determining the levels of MDA and GSH in lung tissue and the expression level of SP-A can be of great importance in diagnosing SWD and the circumstances of death. A better understanding of the physiology of submersion is essential for its possible repercussions in adopting measures in the approach to patients who have survived a submersion process. It is also necessary for forensic pathology to correctly interpret the events that lead to submersion.

New approach to establish a surgical planning in infantile vallecular cyst synchronous with laryngomalacia based on aerodynamic analysis

Background and objectivesA large proportion of infants with vallecular cyst (VC) have coexisting laryngomalacia (LM). Feeding difficulties, regurgitation, occasional cough, and sleep-disordered breathing are the common symptoms in moderate to severe cases. The surgical management of these cases is more challenging and remains controversial. The purpose of this study is to help surgeons select the effective surgical strategies by computer-aided design (CAD) and computational fluid dynamics (CFD) simulations of the upper airway flow characteristics. MethodsThe three dimensional (3D) geometric model of the upper airway was reconstructed based on two dimensional (2D) medical images of the patient with VC accompanied with LM. Virtual surgeries were carried out preoperatively to simulate three possible post-operative states in silico. The different outcomes of virtual surgical strategies were predicted based on computational evaluations of airway fluid dynamics including pressure, resistance, velocity, and wall shear stress (WSS). ResultsThe CFD results of this study suggested the importance of the angle between the rim of epiglottis and arytenoid epiglottic (AE) fold. There was a small impact on the upper airway flow field while the VC was removed and the angle of epiglottis was unchanged. The partial lifting of epiglottis can further improve the flow field. With performing supraglottoplasty (SGP) and the marsupialization of VC, epiglottis was completely recovered, and the flow field was significantly improved. The clinical symptoms of this patient improved greatly after surgeries and no recurrence or growth retardation were noted during 1-year follow-up. The clinical prognosis was consistent with the prediction of the CFD results. ConclusionsThe state of epiglottis needs to be carefully checked to evaluate the necessity of performing further SGP in the patients with VC accompanied with LM. CFD and CAD could be developed as a new approach to help surgeons predict the post-operative outcomes through quantification of the airflow dynamics, and make the optimal and individualized surgical approaches for patients with airway obstruction.

21: EXPRESSION PATTERNS OF AIRWAY FLUID CYTOKINES FROM CHILDREN WITH PEDIATRIC ARDS

Introduction: Pediatric acute respiratory distress syndrome (PARDS) is a heterogeneous illness affecting 6% of mechanically ventilated children and with an overall mortality of 17%. Studies in PARDS have mainly focused on plasma biomarkers which may not reflect airway biomarkers. We lack adequate understanding of the inflammatory mediators and underlying immune responses in the airways of PARDS patients. Our objective was to compare the levels of cytokines in the airway fluid of intubated children with severe versus non-severe PARDS. Methods: We performed a prospective observational cohort study in a single 36-bed quaternary care academic safety-net hospital pediatric ICU. We enrolled children aged 14 days - 17 years intubated for acute respiratory failure between January 2018 and November 2021 that met PALICC-1 criteria for PARDS. We measured levels of 23 cytokines, chemokines, and protein biomarkers in the tracheal aspirate from 49 intubated children with PARDS and stratified patients as severe PARDS (OI>16 or OSI>12.3) or non-severe (OI 4 to 16 or OSI 5 to 12.3). Results: Cytokine levels were normalized to total protein and compared between patients with severe and non-severe PARDS. Levels of interleukin (IL) -4, -5, -6, -7, -8, -12(p-70), -17a, -21, fractalkine, IFN-γ, macrophage inflammatory protein-1a (MIP-1a), and MIP-1b were higher in patients with severe versus non-severe PARDS. Conclusions: This is the first large study to measure levels of multiple cytokines in the airway fluid of patients with PARDS, demonstrating numerous cytokines that are elevated in patients with severe PARDS compared to non-severe disease. Whether clusters of children with a hyperinflammatory vs. hypoinflammatory cytokine profile exist requires a larger sample size and external cohort for discovery and validation.

Expression Patterns of Airway Fluid Cytokines From Intubated Children With Pediatric Acute Respiratory Distress Syndrome.

Prospective observational cohort study. Single 36-bed quaternary care academic safety-net hospital PICU. Children intubated for acute respiratory failure between January 2018 and November 2021 stratified by Pediatric Acute Lung Injury Consensus Conference-1 criteria for PARDS. None. We measured levels of 23 cytokines, chemokines, and protein biomarkers in the tracheal aspirate from 82 intubated children, between 14 days and 17 years old, at risk for or with PARDS. Levels of interleukin-4, -5, -7, -8, -12(p-70), -17a, -21, and fractalkine were higher in patients with severe versus nonsevere PARDS. There were no associations between airway and plasma cytokines. Proinflammatory cytokines are elevated in the airway fluid from intubated children with severe PARDS and reflect diverse patterns of airway inflammation.

Drug Repurposing for Cystic Fibrosis: Identification of Drugs That Induce CFTR-Independent Fluid Secretion in Nasal Organoids.

Individuals with cystic fibrosis (CF) suffer from severe respiratory disease due to a genetic defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which impairs airway epithelial ion and fluid secretion. New CFTR modulators that restore mutant CFTR function have been recently approved for a large group of people with CF (pwCF), but ~19% of pwCF cannot benefit from CFTR modulators Restoration of epithelial fluid secretion through non-CFTR pathways might be an effective treatment for all pwCF. Here, we developed a medium-throughput 384-well screening assay using nasal CF airway epithelial organoids, with the aim to repurpose FDA-approved drugs as modulators of non-CFTR-dependent epithelial fluid secretion. From a ~1400 FDA-approved drug library, we identified and validated 12 FDA-approved drugs that induced CFTR-independent fluid secretion. Among the hits were several cAMP-mediating drugs, including β2-adrenergic agonists. The hits displayed no effects on chloride conductance measured in the Ussing chamber, and fluid secretion was not affected by TMEM16A, as demonstrated by knockout (KO) experiments in primary nasal epithelial cells. Altogether, our results demonstrate the use of primary nasal airway cells for medium-scale drug screening, target validation with a highly efficient protocol for generating CRISPR-Cas9 KO cells and identification of compounds which induce fluid secretion in a CFTR- and TMEM16A-indepent manner.

Post-endotoxin exposure-induced lung inflammation and resolution consequences beneficially impacted by lung-delivered IL-10 therapy

Although lung diseases typically result from long-term exposures, even a robust, one-time exposure can result in long-lasting consequences. Endotoxin is a ubiquitous environmental/occupational inflammatory agent often used to model airway inflammation. Using a murine model, the return to lung homeostasis following high dose inhalant lipopolysaccharide (LPS, 10–100 μg) exposure were delineated over 2 weeks. LPS-induced rapid weight loss, release of proinflammatory mediators, and inflammatory cell influx with prolonged persistence of activated macrophages CD11c+CD11b+ and recruited/transitioning CD11cintCD11b+ monocyte-macrophages out to 2 weeks. Next, lung-delivered recombinant (r) interleukin (IL)-10 was intratracheally administered for 3 doses initiated 5 h following LPS (10 μg) exposure for 2 days. IL-10 therapy reduced LPS-induced weight loss and increased blood glucose levels. Whereas there was no difference in LPS-induced bronchoalveolar lavage airway fluid cellular influx, total lung cell infiltrates were reduced (37%) with rIL-10 treatment. Post-LPS exposure treatment with rIL-10 strikingly reduced lavage fluid and lung homogenate levels of tumor necrosis factor-α (88% and 93% reduction, respectively), IL-6 (98% and 94% reduction), CXCL1 (66% and 75% reduction), and CXCL2 (47% and 67% reduction). LPS-induced recruited monocyte-macrophages (CD11cintCD11b+) were reduced (68%) with rIL-10. Correspondingly, LPS-induced lung tissue CCR2+ inflammatory monocyte-macrophage were reduced with rIL-10. There were also reductions in LPS-induced lung neutrophils, lymphocyte subpopulations, collagen content, and vimentin expression. These findings support the importance of studying resolution processes for the development of treatment after unintended environmental/occupational biohazard exposures. Short-term, lung-delivered rIL-10 favorably hastened inflammatory recovery processes following acute, high dose inhalant LPS exposure.

384 Impact of elexacaftor/tezacaftor/ivacaftor therapy on pathological reprogramming of lung-recruited neutrophils conditioned by cystic fibrosis airway fluid

384 Impact of elexacaftor/tezacaftor/ivacaftor therapy on pathological reprogramming of lung-recruited neutrophils conditioned by cystic fibrosis airway fluid

Management of Respiratory Failure in Patients with COVID-19 and Multiple Myeloma

Background: Cancer patients have higher risk of getting COVID-19. Individuals with malignancy who infected COVID-19 often underwent prolonged hospitalization or death. Here, we report respiratory failure management of of COVID-19 patient with multiple myeloma (MM). Case: A 66-year-old man came with complaints of shortness of breath. The patient was intubated and treated in the intensive care COVID. Patients with a history of multiple myeloma and who have chemotherapy cycle. The laboratory results showed an increase in markers of inflammation, hypoalbuminemia, and bicytopenia. The results of the polymerase chain reaction swab were positive. There are 4 managements in this patient, airway management: intubation and ventilator settings using the Lung Protective Strategy principle. Management Breathing: administration of antibiotics according to sputum culture results. Circulation Management: Fluid management using a non-invasive Contractility Index (ICON) monitor. Management of Disability: Spontaneous Awakening Trial (SAT) and Spontaneous Breathing Trial (SBT) when the aggravating disease has been handled. Conclusion: Management of respiratory failure in patients with multiple myeloma and COVID-19 infection is primarily focused on supportive care such as airway management, breathing management, fluid management and disability management.

Exhaled Breath Condensate Analysis in Chronic Obstructive Pulmonary Disease

The increasing focus on airway inflammation in the pathogenesis of chronic obstructive pulmonary disease (COPD) has led to development and evolution of tools to measure it. Direct assessment of airway inflammation requires invasive procedures, and hence, has obvious limitations. Non-invasive methods to sample airway secretions and fluids offer exciting prospects. Analysis of exhaled breath condensate (EBC) is rapidly emerging as a novel non-invasive approach for sampling airway epithelial lining fluid and offers a convenient tool to provide biomarkers of inflammation. It has definite advantages that make it an attractive and a feasible option. It is a source of mediators and molecules that are the causes or consequences of the inflammatory process. Measurement of such markers is increasingly being explored for studying airway inflammation qualitatively and quantitatively in research studies and for potential clinical applications. These biomarkers also have the potential to develop into powerful research tools in COPD for identifying various pathways of pathogenesis of COPD that may ultimately provide specific targets for therapeutic intervention. The EBC analysis is still an evolving noninvasive method for monitoring of inflammation and oxidative stress in the airways. The limited number of studies available on EBC analysis in COPD have provided useful information although definite clinical uses are yet to be defined. Evolving technologies of genomics, proteomics, and metabonomics may provide deeper and newer insights into the molecular mechanisms underlying the pathogenesis of COPD.

Pathological metabolic adaptation of neutrophils recruited to cystic fibrosis airway microenvironment can not be reversed by modulator therapy

Abstract Background Neutrophilic inflammation is a hallmark of cystic fibrosis (CF) lung disease. Prior studies from our group show that blood neutrophils undergo metabolic and functional adaptations upon entry into the CF lung lumen that causes them to become anabolic, while repressing bacterial killing function and enhancing degranulation. The recent advent of highly effective modulator therapy (HEMT) for the CFTR channel (mutated in CF) has improved patient outcomes, but it is unclear how HEMT impact CF lung neutrophilic inflammation. Method We used an organotypic model in which blood neutrophils are transmigrated through differentiated airway epithelial cells towards a chemoattractant control (leukotriene B4, LTB4), or airway supernatant from CF patients not on HEMT (CFASN) or on HEMT (CFMOD). We conducted phenotypic (FACS, CFU-assay) and metabolomic (metabolomics, 13C6-glucose tracing) analysis of the transmigrated neutrophils. Results CFMOD-recruited neutrophils contained ivacaftor (a HEMT drug), demonstrating exposure to the therapy. Compared to LTB4-recruited neutrophils, CFASN/CFMOD-recruited neutrophils showed increased AMP, GMP and intracellular and secreted metabolites related to citric acid cycle activity. 13C6-glucose flux indicated similar rates of extracellular glucose utilization in all transmigrated neutrophils, but higher total glycolysis to lactate in CFASN/CFMOD-transmigrated neutrophils. Conclusion Pathological metabolic adaptations of neutrophils following transmigration into CF airway fluid are not substantially altered by HEMT. Further studies are needed to assess the potential impact on functional adaptations by these cells. Supported by NIH (R56 HL150658), Cystic Fibrosis Foundation (CAMMAR21F0, TIROUV19G0), I3 Teams Research Award (Emory), and CF@LANTA, a component of Emory University and Children’s Healthcare of Atlanta.

Safety of chronic hypertonic bicarbonate inhalation in a cigarette smoke-induced airway irritation guinea pig model

BackgroundCystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) are often associated with airway fluid acidification. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene leads to impaired bicarbonate secretion contributing to CF airway pathology. Chronic cigarette smoke (CS) -the major cause of COPD- is reported to induce acquired CFTR dysfunction underlying airway acidification and inflammation. We hypothesize that bicarbonate-containing aerosols could be beneficial for patients with CFTR dysfunctions. Thus, we investigated the safety of hypertonic sodium bicarbonate (NaHCO3) inhalation in CS-exposed guinea pigs.MethodsAnimals were divided into groups inhaling hypertonic NaCl (8.4%) or hypertonic NaHCO3 (8.4%) aerosol for 8 weeks. Subgroups from each treatment groups were further exposed to CS. Respiratory functions were measured at 0 and after 2, 4, 6 and 8 weeks. After 8 weeks blood tests and pulmonary histopathological assessment were performed.ResultsNeither smoking nor NaHCO3-inhalation affected body weight, arterial and urine pH, or histopathology significantly. NaHCO3-inhalation did not worsen respiratory parameters. Moreover, it normalized the CS-induced transient alterations in frequency, peak inspiratory flow, inspiratory and expiratory times.ConclusionLong-term NaHCO3-inhalation is safe in chronic CS-exposed guinea pigs. Our data suggest that bicarbonate-containing aerosols might be carefully applied to CF patients.