Assessing the potential of GPT-4 to perpetuate racial and gender biases in health care: a model evaluation study.

BACKGROUND: Large language models (LLMs) such as GPT-4 hold great promise as transformative tools in health care, ranging from automating administrative tasks to augmenting clinical decision making. However, these models also pose a danger of perpetuating biases and delivering incorrect medical diagnoses, which can have a direct, harmful impact on medical care. We aimed to assess whether GPT-4 encodes racial and gender biases that impact its use in health care. METHODS: Using the Azure OpenAI application interface, this model evaluation study tested whether GPT-4 encodes racial and gender biases and examined the impact of such biases on four potential applications of LLMs in the clinical domain-namely, medical education, diagnostic reasoning, clinical plan generation, and subjective patient assessment. We conducted experiments with prompts designed to resemble typical use of GPT-4 within clinical and medical education applications. We used clinical vignettes from NEJM Healer and from published research on implicit bias in health care. GPT-4 estimates of the demographic distribution of medical conditions were compared with true US prevalence estimates. Differential diagnosis and treatment planning were evaluated across demographic groups using standard statistical tests for significance between groups. FINDINGS: We found that GPT-4 did not appropriately model the demographic diversity of medical conditions, consistently producing clinical vignettes that stereotype demographic presentations. The differential diagnoses created by GPT-4 for standardised clinical vignettes were more likely to include diagnoses that stereotype certain races, ethnicities, and genders. Assessment and plans created by the model showed significant association between demographic attributes and recommendations for more expensive procedures as well as differences in patient perception. INTERPRETATION: Our findings highlight the urgent need for comprehensive and transparent bias assessments of LLM tools such as GPT-4 for intended use cases before they are integrated into clinical care. We discuss the potential sources of these biases and potential mitigation strategies before clinical implementation. FUNDING: Priscilla Chan and Mark Zuckerberg.

Randomized Phase 2 Placebo-Controlled Trial of Nintedanib for the Treatment of Radiation Pneumonitis.

PURPOSE: Radiation pneumonitis (RP) is the most common dose-limiting toxicity for thoracic radiation therapy. Nintedanib is used for the treatment of idiopathic pulmonary fibrosis, which shares pathophysiological pathways with the subacute phase of RP. Our goal was to investigate the efficacy and safety of nintedanib added to a prednisone taper compared with a prednisone taper alone in reducing pulmonary exacerbations in patients with grade 2 or higher (G2+) RP. METHODS AND MATERIALS: In this phase 2, randomized, double-blinded, placebo-controlled trial, patients with newly diagnosed G2+ RP were randomized 1:1 to nintedanib or placebo in addition to a standard 8-week prednisone taper. The primary endpoint was freedom from pulmonary exacerbations at 1 year. Secondary endpoints included patient-reported outcomes and pulmonary function tests. Kaplan-Meier analysis was used to estimate the probability of freedom from pulmonary exacerbations. The study was closed early due to slow accrual. RESULTS: Thirty-four patients were enrolled between October 2015 and February 2020. Of 30 evaluable patients, 18 were randomized to the experimental Arm A (nintedanib + prednisone taper) and 12 to the control Arm B (placebo + prednisone taper). Freedom from exacerbation at 1 year was 72% (confidence interval, 54%-96%) in Arm A and 40% (confidence interval, 20%-82%) in Arm B (1-sided, P = .037). In Arm A, there were 16 G2+ adverse events possibly or probably related to treatment compared with 5 in the placebo arm. There were 3 deaths during the study period in Arm A due to cardiac failure, progressive respiratory failure, and pulmonary embolism. CONCLUSIONS: There was an improvement in pulmonary exacerbations by the addition of nintedanib to a prednisone taper. Further investigation is warranted for the use of nintedanib for the treatment of RP.

Mouse phospholipid phosphatase 6 regulates dendritic cell cholesterol, macropinocytosis, and allergen sensitization.

Lipid phosphate phosphatases are a family of enzymes with diverse cellular metabolic functions. Phospholipid phosphatase 6 (PLPP6) is a regulator of cellular polyisoprenyl phosphates; however, its in vivo functions remain to be determined. Here, mouse PLPP6 was characterized to possess similar catalytic properties as the human enzyme. Plpp6 knockout mice (Plpp6 -/- ) were generated and displayed decreased airway allergen sensitization, pointing to a role for PLPP6 in the early events of lung allergic responses. Dendritic cell (DC) responses were investigated and endocytosis of allergen via macropinocytosis was decreased in Plpp6 -/- DCs that had lower cholesterol content. When reversed by cholesterol loading, the DC macropinocytosis defect is corrected. Adoptive transfer of Plpp6 -/- DCs to wild-type mice during sensitization was sufficient to decrease allergen-induced responses. Together, our findings have identified PLPP6 as a pivotal regulator of DC cholesterol content and macropinocytosis, cellular mechanisms that are important for pathologic responses in allergen-induced lung inflammation.

Inflammation resolution circuits are uncoupled in acute sepsis and correlate with clinical severity.

Sepsis is a critical illness characterized by dysregulated inflammatory responses lacking counter-regulation. Specialized proresolving mediators are agonists for antiinflammation and for promoting resolution, and they are protective in preclinical sepsis models. Here, in human sepsis, we mapped resolution circuits for the specialized proresolving mediators resolvin D1 and resolvin D2 in peripheral blood neutrophils and monocytes, their regulation of leukocyte activation and function ex vivo, and their relationships to measures of clinical severity. Neutrophils and monocytes were isolated from healthy subjects and patients with sepsis by inertial microfluidics and resolvin D1 and resolvin D2 receptor expression determined by flow cytometry. The impact of these resolvins on leukocyte activation was determined by isodielectric separation and leukocyte function by stimulated phagolysosome formation. Leukocyte proresolving receptor expression was significantly higher in sepsis. In nanomolar concentrations, resolvin D1 and resolvin D2 partially reversed sepsis-induced changes in leukocyte activation and function. Principal component analyses of leukocyte resolvin receptor expression and responses differentiated sepsis from health and were associated with measures of sepsis severity. These findings indicate that resolvin D1 and resolvin D2 signaling for antiinflammation and resolution are uncoupled from leukocyte activation in early sepsis and suggest that indicators of diminished resolution signaling correlate with clinical disease severity.

FcεR1-expressing nociceptors trigger allergic airway inflammation.

BACKGROUND: Lung nociceptor neurons amplify immune cell activity and mucus metaplasia in response to an inhaled allergen challenge in sensitized mice. OBJECTIVE: We sought to identify the cellular mechanisms by which these sensory neurons are activated subsequent to allergen exposure. METHODS: We used calcium microscopy and electrophysiologic recording to assess whether vagal neurons directly respond to the model allergen ovalbumin (OVA). Next, we generated the first nociceptor-specific FcεR1γ knockdown (TRPV1Cre::FcεR1γfl/fl) mice to assess whether this targeted invalidation would affect the severity of allergic inflammation in response to allergen challenges. RESULTS: Lung-innervating jugular nodose complex ganglion neurons express the high-affinity IgE receptor FcεR1, the levels of which increase in OVA-sensitized mice. FcεR1γ-expressing vagal nociceptor neurons respond directly to OVA complexed with IgE with depolarization, action potential firing, calcium influx, and neuropeptide release. Activation of vagal neurons by IgE-allergen immune complexes, through the release of substance P from their peripheral terminals, directly amplifies TH2 cell influx and polarization in the airways. Allergic airway inflammation is decreased in TRPV1Cre::FcεR1γfl/fl mice and in FcεR1α-/- mice into which bone marrow has been transplanted. Finally, increased in vivo circulating levels of IgE following allergen sensitization enhances the responsiveness of FcεR1 to immune complexes in both mouse jugular nodose complex ganglion neurons and human induced pluripotent stem cell-derived nociceptors. CONCLUSIONS: Allergen sensitization triggers a feedforward inflammatory loop between IgE-producing plasma cells, FcεR1-expressing vagal sensory neurons, and TH2 cells, which helps to both initiate and amplify allergic airway inflammation. These data highlight a novel target for reducing allergy, namely, FcεR1γ expressed by nociceptors.

Plasma Levels of Proresolving and Prophlogistic Lipid Mediators: Association With Severity of Respiratory Failure and Mortality in Acute Respiratory Distress Syndrome.

OBJECTIVES: Acute respiratory distress syndrome is characterized by an overly exuberant inflammatory state in the lung. Specialized proresolving mediators are endogenous agonists for the resolution of lung inflammation and injury in health, yet their association with acute respiratory distress syndrome severity and outcomes remains to be defined. In the current study, we investigate associations between plasma levels of specialized proresolving mediators and acute respiratory distress syndrome severity and mortality. DESIGN: Translational pilot study nested within a large prospective cohort of patients with risk factors for acute respiratory distress syndrome. SETTING: ICU from a large medical center. PATIENTS: Twenty-six Caucasian patients with acute respiratory distress syndrome and available plasma from early in critical illness. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Here, in samples from 26 acute respiratory distress syndrome patients, we examined plasma levels of select specialized proresolving mediators that promote lung injury resolution in preclinical systems, namely lipoxin A4 and maresin 1, and select prophlogistic lipid mediators linked to acute respiratory distress syndrome pathogenesis, namely cysteinyl leukotrienes and thromboxane B2. These mediators were detected by sensitive enzyme-linked immunosorbent assay: lipoxin A4 (assay range) (8.2-5,000 pg/mL), maresin 1 (7.8-1,000 pg/mL), cysteinyl leukotrienes (7.8-1,000 pg/mL), and thromboxane B2 (15.6-2,000 pg/mL). Lower plasma levels of specialized proresolving mediators were associated with increased duration of ventilatory support and ICU length of stay. Even in this small sample size, trends were evident for increased cysteinyl leukotrienes to specialized proresolving mediator ratios (cysteinyl leukotrienes/maresin 1 and cysteinyl leukotrienes/lipoxin A4) in acute respiratory distress syndrome nonsurvivors. CONCLUSIONS: Lower specialized proresolving mediator levels in acute respiratory distress syndrome patients may disrupt timely resolution of lung inflammation and/or injury and contribute to clinical severity and mortality.

Novel platform leveraging electronic medical record (EMR) to triage patients admitted with high-grade immune-related adverse events (irAEs) to the immune-toxicity (ITOX) service.

BACKGROUND: The incidence of high-grade immune-related adverse events (irAEs) due to immune checkpoint inhibitors (ICIs) is increasing due to the rapid expansion of indications for their use. There is an urgent need for a feasible approach of identifying patients with high-grade irAEs to ensure early detection and proper management of this unique set of toxicities. METHODS: We established one of the first inpatient services that are specifically devoted to mitigating irAEs. The service uses a multidisciplinary approach with consulting service from experts in managing irAEs. We are leveraging the electronic medical record (EMR) to triage patients who are admitted to the hospital and have received or are currently receiving ICIs. A list of patients with ICI exposure is generated daily by EMR and then curated manually to identify patients with potential irAEs. RESULTS: A total of 129 patients with high-grade irAEs were admitted between June 2018 and June 2019. The most common irAEs were colitis (32%), pneumonitis (30%), and hepatitis (14%). Eighty five per cent of the patients had grade 3 irAEs and 15% had grade 4-5. About half of the patients had received ICI monotherapy; 30% had received combination of ICIs and non-ICIs; and 19% had received a combination of ICIs. Only 9% of patients had steroid-refractory irAEs requiring other immunosuppressive agents. The average length of stay for irAE-related admission was 11 days with a readmission rate due to recurrent irAEs of 26% within a year. CONCLUSION: We demonstrated the feasibility of using the EMR to accurately triage patients with suspected irAEs to a dedicated immune-toxicity service. Our model is adaptable in major academic centers and could have a major impact on quality of care and future clinical research addressing irAEs.

Cysteinyl maresins regulate the prophlogistic lung actions of cysteinyl leukotrienes.

BACKGROUND: Cysteinyl leukotrienes (CysLTs) are potent prophlogistic mediators in asthmatic patients; however, inhibition of CysLT receptor 1 is not a consistently effective treatment, suggesting additional regulatory mechanisms. Other cysteinyl-containing lipid mediators (LMs) derived from docosahexaenoic acid, namely maresin conjugates in tissue regeneration (MCTRs), were recently discovered. Therefore their production and actions in the lung are of considerable interest. OBJECTIVE: We sought to determine MCTR production, bioactions, and mechanisms in the human lung and in patients with experimental allergic airway inflammation. METHODS: LM metabololipidomic profiling of the lung was performed by using liquid chromatography with tandem mass spectrometry. Donor-derived human precision-cut lung slices were exposed to leukotriene (LT) D4, MCTRs, or both before determination of airway contraction. The actions of exogenous MCTRs on murine allergic host responses were determined in the setting of ovalbumin- and house dust mite-induced lung inflammation. RESULTS: Lipidomic profiling showed that the most abundant cysteinyl LMs in healthy human lungs were MCTRs, whereas CysLTs were most prevalent in patients with disease. MCTRs blocked LTD4-initiated airway contraction in human precision-cut lung slices. In mouse allergic lung inflammation MCTRs were present with temporally regulated production. With ovalbumin-induced inflammation, MCTR1 was most potent for promoting resolution of eosinophils, and MCTR3 potently decreased airway hyperreactivity to methacholine, bronchoalveolar lavage fluid albumin, and serum IgE levels. MCTR1 and MCTR3 inhibited lung eosinophilia after house dust mite-induced inflammation. CONCLUSION: These results identified lung MCTRs that blocked human LTD4-induced airway contraction and promoted resolution of murine allergic airway responses when added exogenously. Together, these findings uncover proresolving mechanisms for lung responses that can be disrupted in patients with disease.

Leukocyte function assessed via serial microlitre sampling of peripheral blood from sepsis patients correlates with disease severity.

Dysregulated leukocyte responses underlie the pathobiology of sepsis, which is a leading cause of death. However, measures of leukocyte function are not routinely available in clinical care. Here we report the development and testing of an inertial microfluidic system for the label-free isolation and downstream functional assessment of leukocytes from 50 µl of peripheral blood. We used the system to assess leukocyte phenotype and function in serial samples from 18 hospitalized patients with sepsis and 10 healthy subjects. The sepsis samples had significantly higher levels of CD16dim and CD16- neutrophils and CD16+ 'intermediate' monocytes, as well as significantly lower levels of neutrophil-elastase release, O2- production and phagolysosome formation. Repeated sampling of sepsis patients over 7 days showed that leukocyte activation (measured by isodielectric separation) and leukocyte phenotype and function were significantly more predictive of the clinical course than complete-blood-count parameters. We conclude that the serial assessment of leukocyte function in microlitre blood volumes is feasible and that it provides significantly more prognostic information than leukocyte counting.

Calcitonin Gene-Related Peptide Negatively Regulates Alarmin-Driven Type 2 Innate Lymphoid Cell Responses.

Neuroimmune interactions have emerged as critical modulators of allergic inflammation, and type 2 innate lymphoid cells (ILC2s) are an important cell type for mediating these interactions. Here, we show that ILC2s expressed both the neuropeptide calcitonin gene-related peptide (CGRP) and its receptor. CGRP potently inhibited alarmin-driven type 2 cytokine production and proliferation by lung ILC2s both in vitro and in vivo. CGRP induced marked changes in ILC2 expression programs in vivo and in vitro, attenuating alarmin-driven proliferative and effector responses. A distinct subset of ILCs scored highly for a CGRP-specific gene signature after in vivo alarmin stimulation, suggesting CGRP regulated this response. Finally, we observed increased ILC2 proliferation and type 2 cytokine production as well as exaggerated responses to alarmins in mice lacking the CGRP receptor. Together, these data indicate that endogenous CGRP is a critical negative regulator of ILC2 responses in vivo.

Neutrophil cytoplasts induce TH17 differentiation and skew inflammation toward neutrophilia in severe asthma.

Severe asthma is a debilitating and treatment refractory disease. As many as half of these patients have complex neutrophil-predominant lung inflammation that is distinct from milder asthma with type 2 eosinophilic inflammation. New insights into severe asthma pathogenesis are needed. Concomitant exposure of mice to an aeroallergen and endotoxin during sensitization resulted in complex neutrophilic immune responses to allergen alone during later airway challenge. Unlike allergen alone, sensitization with allergen and endotoxin led to NETosis. In addition to neutrophil extracellular traps (NETs), enucleated neutrophil cytoplasts were evident in the lungs. Surprisingly, allergen-driven airway neutrophilia was decreased in peptidyl arginine deiminase 4-deficient mice with defective NETosis but not by deoxyribonuclease treatment, implicating the cytoplasts for the non-type 2 immune responses to allergen. Neutrophil cytoplasts were also present in mediastinal lymph nodes, and the cytoplasts activated lung dendritic cells in vitro to trigger antigen-specific interleukin-17 (IL-17) production from naïve CD4+ T cells. Bronchoalveolar lavage fluid from patients with severe asthma and high neutrophil counts had detectable NETs and cytoplasts that were positively correlated with IL-17 levels. Together, these translational findings have identified neutrophil cytoplast formation in asthmatic lung inflammation and linked the cytoplasts to T helper 17-mediated neutrophilic inflammation in severe asthma.

Specialized Proresolving Mediators in Innate and Adaptive Immune Responses in Airway Diseases.

Airborne pathogens and environmental stimuli evoke immune responses in the lung. It is critical to health that these responses be controlled to prevent tissue damage and the compromise of organ function. Resolution of inflammation is a dynamic process that is coordinated by biochemical and cellular mechanisms. Recently, specialized proresolving mediators (SPMs) have been identified in resolution exudates. These molecules orchestrate anti-inflammatory and proresolving actions that are cell type specific. In this review, we highlight SPM biosynthesis, the influence of SPMs on the innate and adaptive immune responses in the lung, as well as recent insights from SPMs on inflammatory disease pathophysiology. Uncovering these mediators and cellular mechanisms for resolution is providing new windows into physiology and disease pathogenesis.

Early Intravascular Events Are Associated with Development of Acute Respiratory Distress Syndrome. A Substudy of the LIPS-A Clinical Trial.

RATIONALE: Acute respiratory distress syndrome (ARDS) is a devastating illness with limited therapeutic options. A better understanding of early biochemical and immunological events in ARDS could inform the development of new preventive and treatment strategies. OBJECTIVES: To determine select peripheral blood lipid mediator and leukocyte responses in patients at risk for ARDS. METHODS: Patients at risk for ARDS were randomized as part of a multicenter, double-blind clinical trial of aspirin versus placebo (the LIPS-A [Lung Injury Prevention Study with Aspirin] trial; NCT01504867). Plasma thromboxane B2 (TXB2), aspirin-triggered lipoxin A4 (15-epi-LXA4, ATL), and peripheral blood leukocyte number and activation were determined on enrollment and after treatment with either aspirin or placebo. MEASUREMENTS AND MAIN RESULTS: Thirty-three of 367 subjects (9.0%) developed ARDS after randomization. Baseline ATL levels, total monocyte counts, intermediate monocyte counts, and monocyte-platelet aggregates were associated with the development of ARDS. Peripheral blood neutrophil count and monocyte-platelet aggregates significantly decreased over time. Of note, nine subjects developed ARDS after randomization yet before study drug initiation, including seven subjects assigned to aspirin treatment. Subjects without ARDS at the time of first dose demonstrated a lower incidence of ARDS with aspirin treatment. Compared with placebo, aspirin significantly decreased TXB2 and increased the ATL/TXB2 ratio. CONCLUSIONS: Biomarkers of intravascular monocyte activation in at-risk patients were associated with development of ARDS. The potential clinical benefit of early aspirin for prevention of ARDS remains uncertain. Together, results of the biochemical and immunological analyses provide a window into the early pathogenesis of human ARDS and represent potential vascular biomarkers of ARDS risk. Clinical trial registered with www.clinicaltrials.gov (NCT01504867).

15-epi-Lipoxin A4, Resolvin D2, and Resolvin D3 Induce NF-κB Regulators in Bacterial Pneumonia.

Specialized proresolving mediators (SPMs) decrease NF-κB activity to prevent excessive tissue damage and promote the resolution of acute inflammation. Mechanisms for NF-κB regulation by SPMs remain to be determined. In this study, after LPS challenge, the SPMs 15-epi-lipoxin A4 (15-epi-LXA4), resolvin D1, resolvin D2, resolvin D3, and 17-epi-resolvin D1 were produced in vivo in murine lungs. In LPS-activated human bronchial epithelial cells, select SPMs increased expression of the NF-κB regulators A20 and single Ig IL-1R-related molecule (SIGIRR). Of interest, 15-epi-LXA4 induced A20 and SIGIRR in an lipoxin A4 receptor/formyl peptide receptor 2 (ALX/FPR2) receptor-dependent manner in epithelial cells and in murine pneumonia. This SPM regulated NF-κB-induced cytokines to decrease pathogen-mediated inflammation. In addition to dampening lung inflammation, surprisingly, 15-epi-LXA4 also enhanced pathogen clearance with increased antimicrobial peptide expression. Taken together, to our knowledge these results are the first to identify endogenous agonists for A20 and SIGIRR expression to regulate NF-κB activity and to establish mechanisms for NF-κB regulation by SPMs for pneumonia resolution.

Phospholipase D isoforms differentially regulate leukocyte responses to acute lung injury.

Phospholipase D (PLD) plays important roles in cellular responses to tissue injury that are critical to acute inflammatory diseases, such as the acute respiratory distress syndrome (ARDS). We investigated the expression of PLD isoforms and related phospholipid phosphatases in patients with ARDS, and their roles in a murine model of self-limited acute lung injury (ALI). Gene expression microarray analysis on whole blood obtained from patients that met clinical criteria for ARDS and clinically matched controls (non-ARDS) demonstrated that PLD1 gene expression was increased in patients with ARDS relative to non-ARDS and correlated with survival. In contrast, PLD2 expression was associated with mortality. In a murine model of self-resolving ALI, lung Pld1 expression increased and Pld2 expression decreased 24 h after intrabronchial acid. Total lung PLD activity was increased 24 h after injury. Pld1-/- mice demonstrated impaired alveolar barrier function and increased tissue injury relative to WT and Pld2-/- , whereas Pld2-/- mice demonstrated increased recruitment of neutrophils and macrophages, and decreased tissue injury. Isoform-specific PLD inhibitors mirrored the results with isoform-specific Pld-KO mice. PLD1 gene expression knockdown in human leukocytes was associated with decreased phagocytosis by neutrophils, whereas reactive oxygen species production and phagocytosis decreased in M2-macrophages. PLD2 gene expression knockdown increased neutrophil and M2-macrophage transmigration, and increased M2-macrophage phagocytosis. These results uncovered selective regulation of PLD isoforms after ALI, and opposing effects of selective isoform knockdown on host responses and tissue injury. These findings support therapeutic strategies targeting specific PLD isoforms for the treatment of ARDS.

Erratum: The neuropeptide NMU amplifies ILC2-driven allergic lung inflammation.

This corrects the article DOI: 10.1038/nature24029.

The neuropeptide NMU amplifies ILC2-driven allergic lung inflammation.

Type 2 innate lymphoid cells (ILC2s) both contribute to mucosal homeostasis and initiate pathologic inflammation in allergic asthma. However, the signals that direct ILC2s to promote homeostasis versus inflammation are unclear. To identify such molecular cues, we profiled mouse lung-resident ILCs using single-cell RNA sequencing at steady state and after in vivo stimulation with the alarmin cytokines IL-25 and IL-33. ILC2s were transcriptionally heterogeneous after activation, with subpopulations distinguished by expression of proliferative, homeostatic and effector genes. The neuropeptide receptor Nmur1 was preferentially expressed by ILC2s at steady state and after IL-25 stimulation. Neuromedin U (NMU), the ligand of NMUR1, activated ILC2s in vitro, and in vivo co-administration of NMU with IL-25 strongly amplified allergic inflammation. Loss of NMU-NMUR1 signalling reduced ILC2 frequency and effector function, and altered transcriptional programs following allergen challenge in vivo. Thus, NMUR1 signalling promotes inflammatory ILC2 responses, highlighting the importance of neuro-immune crosstalk in allergic inflammation at mucosal surfaces.

Resolvin D3 and Aspirin-Triggered Resolvin D3 Are Protective for Injured Epithelia.

Acute lung injury is a life-threatening condition caused by disruption of the alveolar-capillary barrier leading to edema, influx of inflammatory leukocytes, and impaired gas exchange. Specialized proresolving mediators biosynthesized from essential fatty acids, such as docosahexaenoic acid, have tissue protective effects in acute inflammation. Herein, we found that the docosahexaenoic acid-derived mediator resolvin D3 (RvD3): 4S,11R,17S-trihydroxydocosa-5Z,7E,9E,13Z,15E,19Z-hexaenoic acid was present in uninjured lungs, and increased significantly 24 to 72 hours after hydrochloric acid-initiated injury. Because of its delayed enzymatic degradation, we used aspirin-triggered (AT)-RvD3: 4S,11R,17R-trihydroxydocosa-5Z,7E,9E,13Z,15E,19Z-hexaenoic acid, a 17R-epimer of RvD3, for in vivo experiments. Histopathological correlates of acid injury (alveolar wall thickening, edema, and leukocyte infiltration) were reduced in mice receiving AT-RvD3 1 hour after injury. AT-RvD3-treated mice had significantly reduced edema, as demonstrated by lower wet/dry weight ratios, increased epithelial sodium channel γ expression, and more lymphatic vessel endothelial hyaluronan receptor 1-positive vascular endothelial growth factor receptor 3-positive lymphatic vessels. Evidence for counterregulation of NF-κB by RvD3 and AT-RvD3 was seen in vitro and by AT-RvD3 in vivo. Increases in lung epithelial cell proliferation and bronchoalveolar lavage fluid levels of keratinocyte growth factor were observed with AT-RvD3, which also promoted cutaneous re-epithelialization. Together, these data demonstrate protective actions of RvD3 and AT-RvD3 for injured mucosa that accelerated restoration of epithelial barrier and function.

Silencing Nociceptor Neurons Reduces Allergic Airway Inflammation.

Lung nociceptors initiate cough and bronchoconstriction. To elucidate if these fibers also contribute to allergic airway inflammation, we stimulated lung nociceptors with capsaicin and observed increased neuropeptide release and immune cell infiltration. In contrast, ablating Nav1.8(+) sensory neurons or silencing them with QX-314, a charged sodium channel inhibitor that enters via large-pore ion channels to specifically block nociceptors, substantially reduced ovalbumin- or house-dust-mite-induced airway inflammation and bronchial hyperresponsiveness. We also discovered that IL-5, a cytokine produced by activated immune cells, acts directly on nociceptors to induce the release of vasoactive intestinal peptide (VIP). VIP then stimulates CD4(+) and resident innate lymphoid type 2 cells, creating an inflammatory signaling loop that promotes allergic inflammation. Our results indicate that nociceptors amplify pathological adaptive immune responses and that silencing these neurons with QX-314 interrupts this neuro-immune interplay, revealing a potential new therapeutic strategy for asthma.