An Analysis of Tube Thoracostomy in Combat Implications for Improved Prehospital Recognition and Treatment.

BACKGROUND: Thoracic trauma occurs frequently in combat and is associated with high mortality. Tube thoracostomy (chest tube) is the treatment for pneumothorax resulting from thoracic trauma, but little data exist to characterize combat casualties undergoing this intervention. We sought to describe the incidence of these injuries and procedures to inform training and materiel development priorities. METHODS: This is a secondary analysis of a Department of Defense Trauma Registry (DoDTR) data set from 2007 to 2020 describing prehospital care within all theaters in the registry. We described all casualties who received a tube thoracostomy within 24 hours of admission to a military treatment facility. Variables described included casualty demographics; abbreviated injury scale (AIS) score by body region, presented as binary serious (=3) or not serious (<3); and prehospital interventions. RESULTS: The database identified 25,897 casualties, 2,178 (8.4%) of whom received a tube thoracostomy within 24 hours of admission. Of those casualties, the body regions with the highest proportions of common serious injury (AIS >3) were thorax 62% (1,351), extremities 29% (629), abdomen 22% (473), and head/neck 22% (473). Of those casualties, 13% (276) had prehospital needle thoracostomies performed, and 19% (416) had limb tourniquets placed. Most of the patients were male (97%), partner forces members or humanitarian casualties (70%), and survived to discharge (87%). CONCLUSIONS: Combat casualties with chest trauma often have multiple injuries complicating prehospital and hospital care. Explosions and gunshot wounds are common mechanisms of injury associated with the need for tube thoracostomy, and these interventions are often performed by enlisted medical personnel. Future efforts should be made to provide a correlation between chest interventions and pneumothorax management in prehospital thoracic trauma.

Juke Stick: A Case of Pediatric Atraumatic Compartment Syndrome.

Compartment syndrome is usually due to trauma but can also have atraumatic causes. It is defined as a compromise of neurovascular and muscle function that presents symptomatically with the six P's: pain, pallor, paresthesia, paralysis, poikilothermia, and pulselessness. Diagnosis is confirmed by a delta pressure of <30 mmHg (diastolic blood pressure minus the compartment pressure). This case details a 15-year-old male football player with atraumatic compartment syndrome in the lateral compartment of the right lower leg. Symptoms of swelling and pain began 2 weeks before presentation after the patient was "juked." The patient's symptoms improved after a week of rest but worsened when he returned to practice. In the emergency department, the patient was able to ambulate with pain and declined pain medication. Examination revealed severe tenderness, mildly decreased strength, decreased sensation, and edema in the lateral compartment via bedside ultrasound. Because of the concern for compartment syndrome, pressure was checked with a disposable manometer (Compass CT disposable pressure transducer) revealing a delta pressure of 26 mmHg. The patient consequently underwent fasciotomy, eventually returning to baseline function without deficits. Awareness of this atypical presentation of compartment syndrome will assist providers in making a critical diagnosis and preventing severe complications and disability. This case also demonstrates the potential of disposable pressure transducers for cost-effective and accurate diagnostic confirmation of compartment syndrome in the emergency department.

Quantification of Organophosphorus Insecticide Removed by Gastric Lavage in Acutely Poisoned Patients: An Observational Study.

Introduction: The effectiveness of gastric lavage in organophosphorus (OP) poisoning has not been established. We assessed the ability of gastric lavage to remove OP insecticides as a preliminary stage in assessing effectiveness. Patients and methods: Organophosphorus poisoning patients presenting within 6 hours were included, irrespective of prior gastric lavage. A nasogastric tube was placed and gastric contents aspirated, followed by at least three cycles of gastric lavage with 200 mL of water. Samples from the initial aspirate and the first three lavage cycles were sent for identification and quantification of the OP compounds. Patients were monitored for complications of gastric lavage. Results: Around 42 patients underwent gastric lavage. Eight (19.0%) patients were excluded from the study because of a lack of analytical standards for ingested compounds. Insecticides were detectable in the lavage samples of 24 of 34 (70.6%) patients. Lipophilic OP compounds were detected in 23 of 24 patients, while no hydrophilic OP compounds could be detected in six patients with reported ingestion of hydrophilic compounds. For chlorpyrifos poisoning (n = 10), only 0.65 mg (SD 1.2) of the estimated ingested amount (n = 5) of 8,600 mg (SD 3,200) was recovered by gastric lavage. The mean proportion of the compound removed by initial gastric aspirate was 79.4% and subsequent three cycles removed 11.5, 6.6, and 2.7%. Conclusion: Lipophilic OP insecticides could be quantified in the stomach contents of OP poisoning patients with the first aspiration or lavage being most effective. The amount removed was very low; hence, routine use of gastric lavage for OP poisoning patients arriving within 6 hours is unlikely to be beneficial. How to cite this article: Mathansingh AJ, Jose A, Fleming JJ, Abhilash KPP, Chandiraseharan VK, Lenin A, et al. Quantification of Organophosphorus Insecticide Removed by Gastric Lavage in Acutely Poisoned Patients: An Observational Study. Indian J Crit Care Med 2023;27(6):397-402.

The Bronchoprotective Effects of Dual Pharmacology, Muscarinic Receptor Antagonist and ß2 Adrenergic Receptor Agonist Navafenterol in Human Small Airways.

Bronchodilators and anti-inflammatory agents are the mainstream treatments in chronic obstructive and pulmonary disease (COPD) and asthma. The combination of ß2 adrenergic receptor (ß2AR) agonists and muscarinic antagonists shows superior bronchoprotective effects compared to these agents individually. Navafenterol (AZD8871) is a single-molecule, dual pharmacology agent combining muscarinic antagonist and ß2AR agonist functions, currently in development as a COPD therapeutic. In precision-cut human lung slices (hPCLS), we investigated the bronchoprotective effect of navafenterol against two non-muscarinic contractile agonists, histamine and thromboxane A2 (TxA2) analog (U46619). Navafenterol pre-treatment significantly attenuated histamine-induced bronchoconstriction and ß2AR antagonist propranolol reversed this inhibitory effect. TxA2 analog-induced bronchoconstriction was attenuated by navafenterol pre-treatment, albeit to a lesser magnitude than that of histamine-induced bronchoconstriction. Propranolol completely reversed the inhibitory effect of navafenterol on TxA2 analog-induced bronchoconstriction. In the presence of histamine or TxA2 analog, navafenterol exhibits bronchoprotective effect in human airways and it is primarily mediated by ß2AR agonism of navafenterol.

Starving a Cell Promotes Airway Smooth Muscle Relaxation: Inhibition of Glycolysis Attenuates Excitation-Contraction Coupling.

Bronchomotor tone modulated by airway smooth muscle shortening represents a key mechanism that increases airway resistance in asthma. Altered glucose metabolism in inflammatory and airway structural cells is associated with asthma. Although these observations suggest a causal link between glucose metabolism and airway hyperresponsiveness, the mechanisms are unclear. We hypothesized that glycolysis modulates excitation-contraction coupling in human airway smooth muscle (HASM) cells. Cultured HASM cells from human lung donors were subject to metabolic screenings using Seahorse XF cell assay. HASM cell monolayers were treated with vehicle or PFK15 (1-(Pyridin-4-yl)-3-(quinolin-2-yl)prop-2-en-1-one), an inhibitor of PFKFB3 (PFK-1,6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3) that generates an allosteric activator for glycolysis rate-limiting enzyme PFK1 (phosphofructokinase 1), for 5-240 minutes, and baseline and agonist-induced phosphorylation of MLC (myosin light chain), MYPT1 (myosin phosphatase regulatory subunit 1), Akt, RhoA, and cytosolic Ca2+ were determined. PFK15 effects on metabolic activity and contractile agonist-induced bronchoconstriction were determined in human precision-cut lung slices. Inhibition of glycolysis attenuated carbachol-induced excitation-contraction coupling in HASM cells. ATP production and bronchodilator-induced cAMP concentrations were also attenuated by glycolysis inhibition in HASM cells. In human small airways, glycolysis inhibition decreased mitochondrial respiration and ATP production and attenuated carbachol-induced bronchoconstriction. The findings suggest that energy depletion resulting from glycolysis inhibition is a novel strategy for ameliorating HASM cell shortening and bronchoprotection of human small airways.

Crosstalk between CD4+ T Cells and Airway Smooth Muscle in Pediatric Obesity-related Asthma.

Rationale: Pediatric obesity-related asthma is a nonatopic asthma phenotype with high disease burden and few effective therapies. RhoGTPase upregulation in peripheral blood T helper (Th) cells is associated with the phenotype, but the mechanisms that underlie this association are not known. Objectives: To investigate the mechanisms by which upregulation of CDC42 (Cell Division Cycle 42), a RhoGTPase, in Th cells is associated with airway smooth muscle (ASM) biology. Methods: Chemotaxis of obese asthma and healthy-weight asthma Th cells, and their adhesion to obese and healthy-weight nonasthmatic ASM, was investigated. Transcriptomics and proteomics were used to determine the differential effect of obese and healthy-weight asthma Th cell adhesion to obese or healthy-weight ASM biology. Measurements and Main Results: Chemotaxis of obese asthma Th cells with CDC42 upregulation was resistant to CDC42 inhibition. Obese asthma Th cells were more adherent to obese ASM compared with healthy-weight asthma Th cells to healthy-weight ASM. Compared with coculture with healthy-weight ASM, obese asthma Th cell coculture with obese ASM was positively enriched for genes and proteins involved in actin cytoskeleton organization, transmembrane receptor protein kinase signaling, and cell mitosis, and negatively enriched for extracellular matrix organization. Targeted gene evaluation revealed upregulation of IFNG, TNF (tumor necrosis factor), and Cluster of Differentiation 247 (CD247) among Th cell genes, and of Ak strain transforming (AKT), Ras homolog family member A (RHOA), and CD38, with downregulation of PRKCA (Protein kinase C-alpha), among smooth muscle genes. Conclusions: Obese asthma Th cells have uninhibited chemotaxis and are more adherent to obese ASM, which is associated with upregulation of genes and proteins associated with smooth muscle proliferation and reciprocal nonatopic Th cell activation.

Helicopter Crashes in the Deployed Combat Setting: The Department of Defense Trauma Registry Experience.

BACKGROUND: Military helicopter mishaps frequently lead to multiple casualty events with complex injury patterns. Data specific to this mechanism of injury in the deployed setting are limited. We describe injury patterns associated with helicopter crashes. MATERIALS AND METHODS: This is a secondary analysis of a Department of Defense Trauma Registry (DODTR) dataset from 2007 to 2020 seeking to describe prehospital care within all theaters in the registry. We searched within the dataset for casualties injured by helicopter crash. A serious injury was defined by an abbreviated injury scale of =3 by body region. RESULTS: We identified 120 casualties injured by helicopter crash within the dataset. Most were Army (64%), the median age was 30 (interquartile range [IQR] 26-35), and most were male (98%), enlisted service members made up the largest cohort (47%), with most injuries occurring during Operation Enduring Freedom (69%). Only 2 were classified as battle injuries. The median injury severity score was 9 (IQR 4-22). Serious injuries by body region are the following: thorax (27%), head/neck (17%), extremities (17%), abdomen (11%), facial (3%), and skin/superficial (1%). The most common prehospital interventions focused on hypothermia prevention/management (62%) and cervical spine stabilization (32%). Most patients survived to hospital discharge (98%). CONCLUSIONS: Serious injuries to the thorax were most common. Survival was high, although better data capture systems are needed to study deaths that occur prehospital that do not reach military treatment facilities with surgical care to optimize planning and outcomes. The high proportion of nonbattle injuries highlights the risks associated with helicopters in general.

Obesity elicits a unique metabolomic signature in human airway smooth muscle cells.

Obesity can aggravate asthma by enhancing airway hyperresponsiveness (AHR) and attenuating response to treatment. However, the precise mechanisms linking obesity and asthma remain unknown. Human airway smooth muscle (HASM) cells exhibit amplified excitation-contraction (EC) coupling and force generation in obesity. Therefore, we posit that airway smooth muscle (ASM) cells obtained from obese donors manifest a metabolomic phenotype distinct from that of nonobese donor cells and that a differential metabolic phenotype, at least in part, drives enhanced ASM cell EC coupling. HASM cells derived from age-, sex-, and race-matched nonobese [body mass index (BMI) ≤ 24.9 kg·m-2] and obese (BMI ≥ 29.9 kg·m-2) lung donors were subjected to unbiased metabolomic screening. The unbiased metabolomic screening identified differentially altered metabolites linked to glycolysis and citric acid cycle in obese donor-derived cells compared with nonobese donor cells. The Seahorse assay measured the bioenergetic profile based on glycolysis, mitochondrial respiration, palmitate oxidation, and glutamine oxidation rates in HASM cells. Glycolytic rate and capacity were elevated in obese donor-derived HASM cells, whereas mitochondrial respiration, palmitate oxidation, and glutamine oxidation rates were comparable between obese and nonobese groups. PFKFB3 mRNA and protein expression levels were also elevated in obese donor-derived HASM cells. Furthermore, pharmacological inhibition of PFKFB3 attenuated agonist-induced myosin light chain (MLC) phosphorylation in HASM cells derived from obese and nonobese donors. Our findings identify elevated glycolysis as a signature metabolic phenotype of obesity and inhibition of glycolysis attenuates MLC phosphorylation in HASM cells. These findings identify novel therapeutic targets to mitigate AHR in obesity-associated asthma.

Role of hyperhomocysteinemia and Vitamin B12 deficiency in central and hemi-central retinal vein occlusion: A case-control study.

BACKGROUND: Retinal venous occlusive diseases have been recognized as a major cause of ocular morbidity. Hyperhomocysteinemia could be a potentially modifiable risk factor. OBJECTIVE: To determine the association of hyperhomocysteinemia with central and hemi-central retinal vein occlusion (CRVO and HCRVO), the correlation of serum levels of homocysteine with Vitamin B12 and folate levels and the association of Vitamin B12 deficiency with hyperhomocysteinemia. METHODS: In this case-control study, patients with CRVO and HCRVO, and age- and gender-matched controls without CRVO and HCRVO, who met the eligibility criteria, were enrolled after obtaining informed consent. Data obtained from participants using a questionnaire, complete ophthalmological examination and relevant investigations, including estimation of serum homocysteine, Vitamin B12 and folate levels, were collated and analyzed. RESULTS: Thirty-nine cases with CRVO and HCRVO and 39 age- and gender-matched controls were studied. We found a significant association of hypertension (P < 0.01), hyperlipidemia (P = 0.01), and abnormal blood profile (P < 0.01) with retinal vein occlusion. There was no statistically significant association of hyperhomocysteinemia with CRVO and HCRVO (P = 0.81). However, we found a high prevalence of both hyperhomocysteinemia (43.58% of cases and 53.84% of controls; P = 0.81) and Vitamin B12 deficiency (23.08% of cases and 38.46% of controls; P = 0.14) in cases and controls, without a statistically significant difference between the two groups with respect to both parameters. Our study also found a negative correlation of serum levels of homocysteine with Vitamin B12 (Pearson correlation co-efficient - 0.3874, P = 0.0005), and folate (Pearson correlation coefficient - 0.3886, P = 0.0004) of the study participants. Among the study participants (n = 78), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 7.0 (2.26-21.72) times those of patients without Vitamin B12 deficiency (P = 0.001). Similarly, among the cases (CRVO, n = 39), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 7.0 (1.22-40.09) times those of patients without Vitamin B12 deficiency (P = 0.029). In the control group also (non-CRVO, n = 39), the odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were 6.67 (1.47-30.21) times those of patients without Vitamin B12 deficiency (P = 0.014). CONCLUSION: Hyperhomocysteinemia was not found to be an independent risk factor for retinal vein occlusion in our study. However, we found a high prevalence of hyperhomocysteinemia and Vitamin B12 deficiency in both cases and controls, without a statistically significant difference between the two groups with respect to both parameters. We also found a negative correlation of serum homocysteine levels with Vitamin B12 and folate levels. The odds of patients with Vitamin B12 deficiency having hyperhomocysteinemia were seven times those of patients without Vitamin B12 deficiency. Hypertension, hyperlipidemia, and abnormal blood profile had a significant association with CRVO and HCRVO. Many of the systemic risk factors for retinal vein occlusions are found to be associated with elevation of serum homocysteine levels, which may be part of a final common pathway in bringing about a state of accelerated atherosclerosis, leading to CRVO or HCRVO. Therefore, lowering serum levels of homocysteine by Vitamin B12 and folate supplementation could have a role in the prevention of these diseases.

Clinical presentation of type 1 and type 2 pyrethroid poisoning in humans.

BACKGROUND: It is unclear if the clinical presentation of poisoning with type 1 and type 2 pyrethroid compounds is different. This study was undertaken to detail the clinical profile and outcome of patients presenting with pyrethroid poisoning and to quantify serum pyrethroid levels. PATIENTS AND METHODS: In this prospective study, patients were categorised as poisoning with type 1 pyrethroids or type 2 pyrethroids. Blood samples were sent for compound identification and quantification. Clinical features and outcomes were compared between the two groups. Factors associated with moderate and severe toxicity were explored using univariate logistic regression analysis and presented as odds ratio (OR) and 95% confidence intervals (CI). RESULTS: Type 1 pyrethroids were implicated in 16 patients and type 2 in 43 patients. The incidence of nausea and vomiting (81.2% vs. 81.3%) and tremor (37.5% vs. 32.6%) were similar in type 1 and type 2 poisoning; paraesthesia (6.2% vs. 32.6%, p = 0.04), hypersalivation (0% vs. 20.9%, p = 0.04), seizures (0% vs. 7%, p = 0.29) and depressed sensorium (0% vs. 18.6%, p = 0.03.) were observed more frequently in type 2 pyrethroid poisoning. Pyrethroids were detected in the serum samples of 24 patients; quantification was possible in 22 patients in whom serum levels ranged from 1.1 to 453 µg/ml. The compounds were undetectable in 35 patients. Two patients (lambda-cyhalothrin poisoning and cypermethrin poisoning) required intubation for low sensorium and respiratory distress. The median (interquartile range) duration of hospitalization was 12 (12-24) hours. All patients survived. Factors associated with moderate and severe toxicity included ingestion of a type 2 pyrethroid, lambda-cyhalothrin (OR 7.81, 95%CI 1.55-39.37, p = 0.01) and volume ingested (OR 1.01, 95%CI 1.00-1.02, p = 0.02). CONCLUSION: Patients with pyrethroid poisoning present predominantly with mild to moderate symptoms. Paraesthesia and hypersalivation are more frequent in type 2 poisoning. A favourable outcome can be expected.

Inhibition of ABCC1 Decreases cAMP Egress and Promotes Human Airway Smooth Muscle Cell Relaxation.

In most living cells, the second-messenger roles for adenosine 3',5'-cyclic monophosphate (cAMP) are short-lived, confined to the intracellular space, and tightly controlled by the binary switch-like actions of Gαs (stimulatory G protein)-activated adenylyl cyclase (cAMP production) and cAMP-specific PDE (cAMP breakdown). Here, by using human airway smooth muscle (HASM) cells in culture as a model, we report that activation of the cell-surface ß2AR (ß2-adrenoceptor), a Gs-coupled GPCR (G protein-coupled receptor), evokes cAMP egress to the extracellular space. Increased extracellular cAMP levels ([cAMP]e) are long-lived in culture and are induced by receptor-dependent and receptor-independent mechanisms in such a way as to define a universal response class of increased intracellular cAMP levels ([cAMP]i). We find that HASM cells express multiple ATP-binding cassette (ABC) membrane transporters, with ABCC1 (ABC subfamily member C 1) being the most highly enriched transcript mapped to MRPs (multidrug resistance-associated proteins). We show that pharmacological inhibition or downregulation of ABCC1 with siRNA markedly reduces ß2AR-evoked cAMP release from HASM cells. Furthermore, inhibition of ABCC1 activity or expression decreases basal tone and increases ß-agonist-induced HASM cellular relaxation. These findings identify a previously unrecognized role for ABCC1 in the homeostatic regulation of [cAMP]i in HASM that may be conserved traits of the Gs-GPCRs (Gs-coupled family of GPCRs). Hence, the general features of this activation mechanism may uncover new disease-modifying targets in the treatment of airflow obstruction in asthma. Surprisingly, we find that serum cAMP levels are elevated in a small cohort of patients with asthma as compared with control subjects, which warrants further investigation.

Metabolomics in asthma: A platform for discovery.

Asthma, characterized by airway hyperresponsiveness, inflammation and remodeling, is a chronic airway disease with complex etiology. Severe asthma is characterized by frequent exacerbations and poor therapeutic response to conventional asthma therapy. A clear understanding of cellular and molecular mechanisms of asthma is critical for the discovery of novel targets for optimal therapeutic control of asthma. Metabolomics is emerging as a powerful tool to elucidate novel disease mechanisms in a variety of diseases. In this review, we summarize the current status of knowledge in asthma metabolomics at systemic and cellular levels. The findings demonstrate that various metabolic pathways, related to energy metabolism, macromolecular biosynthesis and redox signaling, are differentially modulated in asthma. Airway smooth muscle cell plays pivotal roles in asthma by contributing to airway hyperreactivity, inflammatory mediator release and remodeling. We posit that metabolomic profiling of airway structural cells, including airway smooth muscle cells, will shed light on molecular mechanisms of asthma and airway hyperresponsiveness and help identify novel therapeutic targets.

TGF-ß: The missing link in obesity-associated airway diseases?

Obesity is emerging as a global public health epidemic. The co-morbidities associated with obesity significantly contribute to reduced quality of life, mortality, and global healthcare burden. Compared to other asthma comorbidities, obesity prominently engenders susceptibility to inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), contributes to greater disease severity and evokes insensitivity to current therapies. Unlike in other metabolic diseases associated with obesity, the mechanistic link between obesity and airway diseases is only poorly defined. Transforming growth factor-ß (TGF-ß) is a pleiotropic inflammatory cytokine belonging to a family of growth factors with pivotal roles in asthma. In this review, we summarize the role of TGF-ß in major obesity-associated co-morbidities to shed light on mechanisms of the diseases. Literature evidence shows that TGF-ß mechanistically links many co-morbidities with obesity through its profibrotic, remodeling, and proinflammatory functions. We posit that TGF-ß plays a similar mechanistic role in obesity-associated inflammatory airway diseases such as asthma and COPD. Concerning the role of TGF-ß on metabolic effects of obesity, we posit that TGF-ß has a similar mechanistic role in obesity-associated inflammatory airway diseases in interplay with different comorbidities such as hypertension, metabolic diseases like type 2 diabetes, and cardiomyopathies. Future studies in TGF-ß-dependent mechanisms in obesity-associated inflammatory airway diseases will advance our understanding of obesity-induced asthma and help find novel therapeutic targets for prevention and treatment.

Prehospital Intervention Analysis of Helicopter Crashes in Afghanistan.

BACKGROUND: Based on isolated case reports, military helicopter mishaps often result in multiple critical casualties leading to complicated stabilization and evacuation by healthcare providers. The aim of this retrospective descriptive analysis is to describe the incidence of common prehospital injuries associated with rotary wing crashes in order to improve mission planning and casualty survivability. METHODS: This is a secondary analysis of data from the Prehospital Trauma Registry and the Department of Defense Trauma Registry (DoDTR) from April 2003 through May 2019. We searched within our dataset for all encounters involving aviation crashes. RESULTS: From April 2003 through May 2019 there were 1,357 casualty encounters in the Prehospital Trauma Registry. There were 12 casualties identified injured by aircraft crash, of which, 10 were linkable to the DoDTR for outcome data. All encounters for this sub analysis occurred in Afghanistan in 2014, all were US military service members, and a majority were enlisted conventional forces. Most prehospital interventions focused on hemorrhage control, to include limb tourniquets (n=3), pressure dressings (n=2), and pelvic splint (n=1). One patient received a cervical collar and two patients received temperature control with a hypothermia kit. CONCLUSIONS: In this case series, hemorrhage control and extremity stabilization accounted for the majority of prehospital interventions. Larger datasets are needed to validate findings and extrapolate it into mission planning.

Functional NMDA receptors are expressed by human pulmonary artery smooth muscle cells.

N-methyl-D-aspartate (NMDA) receptors are widely expressed in the central nervous system. However, their presence and function at extraneuronal sites is less well characterized. In the present study, we examined the expression of NMDA receptor subunit mRNA and protein in human pulmonary artery (HPA) by quantitative polymerase chain reaction (PCR), immunohistochemistry and immunoblotting. We demonstrate that both GluN1 and GluN2 subunit mRNAs are expressed in HPA. In addition, GluN1 and GluN2 (A-D) subunit proteins are expressed by human pulmonary artery smooth muscle cells (HPASMCs) in vitro and in vivo. These subunits localize on the surface of HPASMCs and form functional ion channels as evidenced by whole-cell patch-clamp electrophysiology and reduced phenylephrine-induced contractile responsiveness of human pulmonary artery by the NMDA receptor antagonist MK801 under hypoxic condition. HPASMCs also express high levels of serine racemase and vesicular glutamate transporter 1, suggesting a potential source of endogenous agonists for NMDA receptor activation. Our findings show HPASMCs express functional NMDA receptors in line with their effect on pulmonary vasoconstriction, and thereby suggest a novel therapeutic target for pharmacological modulations in settings associated with pulmonary vascular dysfunction.

Melon with a Twist: A Case of Nicotine Overdose After Ingestion and Aspiration of Vape Liquid.

We present the case of an active duty 21-year-old male with severe hypoxic respiratory failure after accidentally ingesting, and subsequently aspirating, vaping liquid while intoxicated. Because of the increasing prevalence of vaping devices, this case highlights a unique risk of vape liquids with concentrated nicotine levels and appetizing labels and aromas. Vaping-associated pulmonary injury has been previously described in multiple publications, but unlike those patients with pathology after inhaling vaping products, our patient ingested and subsequently aspirated the highly nicotinic substance. Most vape liquid products have enough nicotine to result in significant toxicity, which most concerningly can lead to nicotine-induced respiratory failure. This patient's hypoxia appeared to be multifactorial as a result of both nicotine toxicity and aspiration, but ultimately treatment of both focused on supportive measures.In addition to understanding nicotine toxicity, this patient's hypoxia secondary to agitation and aspiration requiring emergent airway management illustrates the importance of understanding the technique of Delayed Sequence Intubation and its proper application in the critical airway algorithm. By treating preoxygenation as a procedure, the patient received adequate oxygenation resulting in successful intubation without harmful desaturation during the procedure.Given the prevalence of tobacco use in the military as well as the increasing popularity of vaping devices, future military providers have a responsibility to their patients to be prepared for similar case presentations. Fortunately, this case demonstrates that when managed properly, otherwise healthy patients without comorbidities often recover without significant long-term sequelae.

FFAR1 activation attenuates histamine-induced myosin light chain phosphorylation and cortical tension development in human airway smooth muscle cells.

BACKGROUND: Activation of free fatty acid receptors (FFAR1 and FFAR4) which are G protein-coupled receptors (GPCRs) with established (patho)physiological roles in a variety of obesity-related disorders, induce human airway smooth muscle (HASM) cell proliferation and shortening. We reported amplified agonist-induced cell shortening in HASM cells obtained from obese lung donors. We hypothesized that FFAR1 modulate excitation-contraction (EC) coupling in HASM cells and play a role in obesity-associated airway hyperresponsiveness. METHODS: In HASM cells pre-treated (30 min) with FFAR1 agonists TAK875 and GW9508, we measured histamine-induced Ca2+ mobilization, myosin light chain (MLC) phosphorylation, and cortical tension development with magnetic twisting cytometry (MTC). Phosphorylation of MLC phosphatase and Akt also were determined in the presence of the FFAR1 agonists or vehicle. In addition, the effects of TAK875 on MLC phosphorylation were measured in HASM cells desensitized to ß2AR agonists by overnight salmeterol treatment. The inhibitory effect of TAK875 on MLC phosphorylation was compared between HASM cells from age and sex-matched non-obese and obese human lung donors. The mean measurements were compared using One-Way ANOVA with Dunnett's test for multiple group comparisons or Student's t-test two-group comparison. For cortical tension measurements by magnetic twisted cytometry, mixed effect model using SAS V.9.2 was applied. Means were considered significant when p ≤ 0.05. RESULTS: Unexpectedly, we found that TAK875, a synthetic FFAR1 agonist, attenuated histamine-induced MLC phosphorylation and cortical tension development in HASM cells. These physiological outcomes were unassociated with changes in histamine-evoked Ca2+ flux, protein kinase B (AKT) activation, or MLC phosphatase inhibition. Of note, TAK875-mediated inhibition of MLC phosphorylation was maintained in ß2AR-desensitized HASM cells and across obese and non-obese donor-derived HASM cells. CONCLUSIONS: Taken together, our findings identified the FFAR1 agonist TAK875 as a novel bronchoprotective agent that warrants further investigation to treat difficult-to-control asthma and/or airway hyperreactivity in obesity.

The odorant receptor OR2W3 on airway smooth muscle evokes bronchodilation via a cooperative chemosensory tradeoff between TMEM16A and CFTR.

The recent discovery of sensory (tastant and odorant) G protein-coupled receptors on the smooth muscle of human bronchi suggests unappreciated therapeutic targets in the management of obstructive lung diseases. Here we have characterized the effects of a wide range of volatile odorants on the contractile state of airway smooth muscle (ASM) and uncovered a complex mechanism of odorant-evoked signaling properties that regulate excitation-contraction (E-C) coupling in human ASM cells. Initial studies established multiple odorous molecules capable of increasing intracellular calcium ([Ca2+]i) in ASM cells, some of which were (paradoxically) associated with ASM relaxation. Subsequent studies showed a terpenoid molecule (nerol)-stimulated OR2W3 caused increases in [Ca2+]i and relaxation of ASM cells. Of note, OR2W3-evoked [Ca2+]i mobilization and ASM relaxation required Ca2+ flux through the store-operated calcium entry (SOCE) pathway and accompanied plasma membrane depolarization. This chemosensory odorant receptor response was not mediated by adenylyl cyclase (AC)/cyclic nucleotide-gated (CNG) channels or by protein kinase A (PKA) activity. Instead, ASM olfactory responses to the monoterpene nerol were predominated by the activity of Ca2+-activated chloride channels (TMEM16A), including the cystic fibrosis transmembrane conductance regulator (CFTR) expressed on endo(sarco)plasmic reticulum. These findings demonstrate compartmentalization of Ca2+ signals dictates the odorant receptor OR2W3-induced ASM relaxation and identify a previously unrecognized E-C coupling mechanism that could be exploited in the development of therapeutics to treat obstructive lung diseases.

Role of CD38/cADPR signaling in obstructive pulmonary diseases.

The worldwide socioeconomical burden associated with chronic respiratory diseases is substantial. Enzymes involved in the metabolism of nicotinamide adenine dinucleotide (NAD) are increasingly being implicated in chronic airway diseases. One such enzyme, CD38, utilizes NAD to produce several metabolites, including cyclic ADP ribose (cADPR), which is involved in calcium signaling in airway smooth muscle (ASM). Upregulation of CD38 in ASM caused by exposure to cytokines or allergens leads to enhanced calcium mobilization by agonists and the development of airway hyperresponsiveness (AHR) to contractile agonists. Glucocorticoids and microRNAs can suppress CD38 expression in ASM, whereas cADPR antagonists such as 8Br-cADPR can directly antagonize intracellular calcium mobilization. Bronchodilators act via CD38-independent mechanisms. CD38-dependent mechanisms could be developed for chronic airway diseases therapy.