Macrophage peroxisomes guide alveolar regeneration and limit SARS-CoV-2 tissue sequelae.

Peroxisomes are vital but often overlooked metabolic organelles. We found that excessive interferon signaling remodeled macrophage peroxisomes. This loss of peroxisomes impaired inflammation resolution and lung repair during severe respiratory viral infections.

Hyperpolarized Xenon-129 MRI: Narrative Review of Clinical Studies, Testing, and Implementation of Advanced Pulmonary In Vivo Imaging and Its Diagnostic Applications.

Hyperpolarized xenon-129 MRI (XeMRI) has emerged as a powerful tool in the identification, evaluation, and assessment of disease endotyping and in response to interventions for a myriad of pulmonary diseases. Growing investigative efforts ranging from basic science to application in translational research have employed XeMRI in the evaluation of pulmonary conditions such as chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), asthma, and cystic fibrosis (CF). The novel feature of XeMRI is its ability to generate anatomic and physiologic readouts of the lung with resolution from the whole lung down to the lobar level.

An aberrant immune-epithelial progenitor niche drives viral lung sequelae.

The long-term physiological consequences of respiratory viral infections, particularly in the aftermath of the COVID-19 pandemic-termed post-acute sequelae of SARS-CoV-2 (PASC)-are rapidly evolving into a major public health concern. While the cellular and molecular aetiologies of these sequelae are poorly defined, increasing evidence implicates abnormal immune responses and/or impaired organ recovery after infection. However, the precise mechanisms that link these processes in the context of PASC remain unclear.

Synthesis and Evaluation of diaryl ether modulators of the leukotriene A hydrolase aminopeptidase activity.

Activation of the aminopeptidase (AP) activity of leukotriene A hydrolase (LTAH) presents a potential therapeutic strategy for resolving chronic inflammation. Previously, ARM1 and derivatives were found to activate the AP activity using the alanine-p-nitroanilide (Ala-pNA) as a reporter group in an enzyme kinetics assay. As an extension of this previous work, novel ARM1 derivatives were synthesized using a palladium-catalyzed Ullmann coupling reaction and screened using the same assay.

A protective role for B-1 cells and oxidation-specific epitope IgM in lung fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a morbid fibrotic lung disease with limited treatment options. The pathophysiology of IPF remains poorly understood, and elucidation of the cellular and molecular mechanisms of IPF pathogenesis is key to the development of new therapeutics. B-1 cells are an innate B cell population which play an important role linking innate and adaptive immunity.

Local, Quantitative Morphometry of Fibroproliferative Lung Injury Using Laminin.

Investigations into the mechanisms of injury and repair in fibroproliferative disease require consideration of the spatial heterogeneity inherent in the disease. Most scoring of fibrotic remodeling in preclinical animal models relies on the modified Ashcroft score, which is an ordinal rubric of macroscopic resolution. The obvious limitations of manual histopathologic scoring have generated an unmet need for unbiased, repeatable scoring of fibroproliferative burden in tissue.

Pulmonary MRI with hyperpolarized xenon-129 demonstrates novel alterations in gas transfer across the air-blood barrier in asthma.

Background: Individuals with asthma can vary widely in clinical presentation, severity, and pathobiology. Hyperpolarized xenon-129 (Xe129) MRI is a novel imaging method to provide 3-D mapping of both ventilation and gas exchange in the human lung.

Purpose: To evaluate the functional changes in adults with asthma as compared to healthy controls using Xe129 MRI.

Proximal immune-epithelial progenitor interactions drive chronic tissue sequelae post COVID-19.

The long-term physiological consequences of SARS-CoV-2, termed Post-Acute Sequelae of COVID-19 (PASC), are rapidly evolving into a major public health concern. The underlying cellular and molecular etiology remain poorly defined but growing evidence links PASC to abnormal immune responses and/or poor organ recovery post-infection. Yet, the precise mechanisms driving non-resolving inflammation and impaired tissue repair in the context of PASC remain unclear.

Hyperpolarized Xenon-129: A New Tool to Assess Pulmonary Physiology in Patients with Pulmonary Fibrosis.

Purpose: The existing tools to quantify lung function in interstitial lung diseases have significant limitations. Lung MRI imaging using inhaled hyperpolarized xenon-129 gas (Xe) as a contrast agent is a new technology for measuring regional lung physiology. We sought to assess the utility of the Xe MRI in detecting impaired lung physiology in usual interstitial pneumonia (UIP).

3D Single-Breath Chemical Shift Imaging Hyperpolarized Xe-129 MRI of Healthy, CF, IPF, and COPD Subjects.

3D Single-breath Chemical Shift Imaging (3D-SBCSI) is a hybrid MR-spectroscopic imaging modality that uses hyperpolarized xenon-129 gas (Xe-129) to differentiate lung diseases by probing functional characteristics. This study tests the efficacy of 3D-SBCSI in differentiating physiology among pulmonary diseases. A total of 45 subjects-16 healthy, 11 idiopathic pulmonary fibrosis (IPF), 13 cystic fibrosis (CF), and 5 chronic obstructive pulmonary disease (COPD)-were given 1/3 forced vital capacity (FVC) of hyperpolarized Xe-129, inhaled for a ~7 s MRI acquisition.

Substrate-dependent modulation of the leukotriene A hydrolase aminopeptidase activity and effect in a murine model of acute lung inflammation.

The aminopeptidase activity (AP) of the leukotriene A hydrolase (LTAH) enzyme has emerged as a therapeutic target to modulate host immunity. Initial reports focused on the benefits of augmenting the LTAH AP activity and clearing its putative pro-inflammatory substrate Pro-Gly-Pro (PGP). However, recent reports have introduced substantial complexity disconnecting the LTAH modulator 4-methoxydiphenylmethane (4MDM) from PGP as follows: (1) 4MDM inhibits PGP hydrolysis and subsequently inhibition of LTAH AP activity, and (2) 4MDM activates the same enzyme target in the presence of alternative substrates.

Utilizing flip angle/TR equivalence to reduce breath hold duration in hyperpolarized Xe 1-point Dixon gas exchange imaging.

Purpose: To reduce scan duration in hyperpolarized Xe 1-point Dixon gas exchange imaging by utilizing flip angle (FA)/TR equivalence.

Methods: Images were acquired in 12 subjects (n = 3 radiation therapy, n = 1 unexplained dyspnea, n = 8 healthy) using both standard (TR = 15 ms, FA = 20°, duration = 15 s, 998 projections) and "fast" (TR = 5.4 ms, FA = 12°, duration = 11.

Image- versus histogram-based considerations in semantic segmentation of pulmonary hyperpolarized gas images.

Purpose: To characterize the differences between histogram-based and image-based algorithms for segmentation of hyperpolarized gas lung images.

Methods: Four previously published histogram-based segmentation algorithms (ie, linear binning, hierarchical k-means, fuzzy spatial c-means, and a Gaussian mixture model with a Markov random field prior) and an image-based convolutional neural network were used to segment 2 simulated data sets derived from a public (n = 29 subjects) and a retrospective collection (n = 51 subjects) of hyperpolarized 129Xe gas lung images transformed by common MRI artifacts (noise and nonlinear intensity distortion). The resulting ventilation-based segmentations were used to assess algorithmic performance and characterize optimization domain differences in terms of measurement bias and precision.

Measures of ventilation heterogeneity mapped with hyperpolarized helium-3 MRI demonstrate a T2-high phenotype in asthma.

Background: Hyperpolarized gas with helium (HHe-3) MR (magnetic resonance) is a noninvasive imaging method which maps and quantifies regions of ventilation heterogeneity (VH) in the lung. VH is an important feature of asthma, but little is known as to how VH informs patient phenotypes.

Purpose: To determine if VH indicators quantified by HHe-3 MR imaging (MRI) predict phenotypic characteristics and map to regions of inflammation in children with problematic wheeze or asthma.

Clinical Impact of Multidisciplinary Outpatient Care on Outcomes of Patients with COPD.

Purpose: Heterogeneous nature of Chronic Obstructive Pulmonary Disease (COPD) must be comprehensively addressed. It is unclear if integrative multidisciplinary disease management (IMDM) can optimize clinical outcomes of patients with COPD.

Methods: A single-center, retrospective cohort observational study with a historical intervention was conducted in a clinic specialized for COPD care.

Effect of Modifier Structure on the Activation of Leukotriene A Hydrolase Aminopeptidase Activity.

Activation of the leukotriene A hydrolase (LTAH) aminopeptidase (AP) activity with 4-methoxydiphenylmethane (4MDM) promoted resolution of neutrophil infiltration in a murine cigarette smoke-induced model for emphysematous chronic obstructive pulmonary disease. Recently, 4-(4-benzylphenyl)thiazol-2-amine (ARM1) was published as a ligand for LTAH with potential anti-inflammatory properties. To investigate the effect of modifier structure on enzyme kinetics of LTAH, a series of analogues bearing structural features of ARM1 and 4MDM were synthesized using trifluoroborate Suzuki coupling reactions.

Suppression of aspirin-mediated eosinophil activation by prostaglandin E: Relevance to aspirin and nonsteroidal anti-inflammatory drug hypersensitivity.

Background: Aspirin-exacerbated respiratory disease (AERD) is characterized by severe, sometimes life-threatening reactions to nonsteroidal anti-inflammatory drugs (NSAIDs). Mechanisms driving the disease include overproduction of leukotrienes and loss of anti-inflammatory prostaglandin E (PGE) production. Many cell types contribute to the disease; however, eosinophils are markedly elevated and are important drivers of pathologic findings.

Role of medical and molecular imaging in COPD.

Chronic obstructive pulmonary disease (COPD) is expected to climb on the podium of the leading causes of mortality worldwide in the upcoming decade. Clinical diagnosis of COPD has classically relied upon detecting irreversible airflow obstruction on pulmonary function testing as a global assessment of pulmonary physiology. However, the outcome is still not favorable to decrease mortality due to COPD.

Leukotriene A4 Hydrolase Activation and Leukotriene B4 Production by Eosinophils in Severe Asthma.

Asthma is associated with the overproduction of leukotrienes (LTs), including LTB4. Patients with severe asthma can be highly responsive to 5-lipoxygenase (5-LO) inhibition, which blocks production of both the cysteinyl LTs and LTB4. Production of LTB4 has traditionally been ascribed to neutrophils, mononuclear phagocytes, and epithelial cells, and acts as a chemoattractant for inflammatory cells associated with asthma.

Validation of claims-based algorithms for pulmonary arterial hypertension.

Administrative claims studies do not adequately distinguish pulmonary arterial hypertension (PAH) from other forms of pulmonary hypertension (PH). Our aim is to develop and validate a set of algorithms using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes and electronic medical records (EMR), to identify patients with PAH. From January 2012 to August 2015, the EMRs of patients with ICD-9-CM codes for PH with an outpatient visit at the University of Texas Medical Branch were reviewed.

Macrophages redirect phagocytosis by non-professional phagocytes and influence inflammation.

Professional phagocytes (such as macrophages) and non-professional phagocytes (such as epithelial cells) clear billions of apoptotic cells and particles on a daily basis. Although professional and non-professional macrophages reside in proximity in most tissues, whether they communicate with each other during cell clearance, and how this might affect inflammation, is not known. Here we show that macrophages, through the release of a soluble growth factor and microvesicles, alter the type of particles engulfed by non-professional phagocytes and influence their inflammatory response.

Ultrapressure liquid chromatography-tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for quantification of 4-methoxydiphenylmethane in pharmacokinetic evaluation.

4-Methoxydiphenylmethane (4-MDM), a selective augmenter of Leukotriene A4 Hydrolase (LTA4H), is a new anti-inflammatory compound for potential treatment of chronic obstructive pulmonary disease (COPD). Currently, there is no liquid chromatography tandem mass spectrometric (LC-MS/MS) method for the quantification of 4-MDM. A major barrier for developing the LC-MS/MS method is the inability of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) to ionize 4-MDM due to its hydrophobicity and lack of any functional group for ionization.