A new tractable method for generating human alveolar macrophage-like cells in vitro to study lung inflammatory processes and diseases.

Alveolar macrophages (AMs) are unique lung resident cells that contact airborne pathogens and environmental particulates. The contribution of human AMs (HAMs) to pulmonary diseases remains poorly understood due to the difficulty in accessing them from human donors and their rapid phenotypic change during in vitro culture. Thus, there remains an unmet need for cost-effective methods for generating and/or differentiating primary cells into a HAM phenotype, particularly important for translational and clinical studies. We developed cell culture conditions that mimic the lung alveolar environment in humans using lung lipids, that is, Infasurf (calfactant, natural bovine surfactant) and lung-associated cytokines (granulocyte macrophage colony-stimulating factor, transforming growth factor-ß, and interleukin 10) that facilitate the conversion of blood-obtained monocytes to an AM-like (AML) phenotype and function in tissue culture. Similar to HAM, AML cells are particularly susceptible to both Mycobacterium tuberculosis and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. This study reveals the importance of alveolar space components in the development and maintenance of HAM phenotype and function and provides a readily accessible model to study HAM in infectious and inflammatory disease processes, as well as therapies and vaccines. IMPORTANCE Millions die annually from respiratory disorders. Lower respiratory track gas-exchanging alveoli maintain a precarious balance between fighting invaders and minimizing tissue damage. Key players herein are resident AMs. However, there are no easily accessible in vitro models of HAMs, presenting a huge scientific challenge. Here, we present a novel model for generating AML cells based on differentiating blood monocytes in a defined lung component cocktail. This model is non-invasive, significantly less costly than performing a bronchoalveolar lavage, yields more AML cells than HAMs per donor, and retains their phenotype in culture. We have applied this model to early studies of M. tuberculosis and SARS-CoV-2. This model will significantly advance respiratory biology research.

A new tractable method for generating Human Alveolar Macrophage Like cells in vitro to study lung inflammatory processes and diseases.

Alveolar macrophages (AMs) are unique lung resident cells that contact airborne pathogens and environmental particulates. The contribution of human AMs (HAM) to pulmonary diseases remains poorly understood due to difficulty in accessing them from human donors and their rapid phenotypic change during in vitro culture. Thus, there remains an unmet need for cost-effective methods for generating and/or differentiating primary cells into a HAM phenotype, particularly important for translational and clinical studies. We developed cell culture conditions that mimic the lung alveolar environment in humans using lung lipids, i.e. , Infasurf (calfactant, natural bovine surfactant) and lung-associated cytokines (GM-CSF, TGF-ß, and IL-10) that facilitate the conversion of blood-obtained monocytes to an AM-Like (AML) phenotype and function in tissue culture. Similar to HAM, AML cells are particularly susceptible to both Mycobacterium tuberculosis and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. This study reveals the importance of alveolar space components in the development and maintenance of HAM phenotype and function, and provides a readily accessible model to study HAM in infectious and inflammatory disease processes, as well as therapies and vaccines. IMPORTANCE: Millions die annually from respiratory disorders. Lower respiratory track gas-exchanging alveoli maintain a precarious balance between fighting invaders and minimizing tissue damage. Key players herein are resident AMs. However, there are no easily accessible in vitro models of HAMs, presenting a huge scientific challenge. Here we present a novel model for generating AML cells based on differentiating blood monocytes in a defined lung component cocktail. This model is non-invasive, significantly less costly than performing a bronchoalveolar lavage, yields more AML cells than HAMs per donor and retains their phenotype in culture. We have applied this model to early studies of M. tuberculosis and SARS-CoV-2. This model will significantly advance respiratory biology research.

Pharyngoesophageal Segment Distention Across Volumes and Pathology.

Purpose Patients receive multiple bolus trials during a videofluoroscopic swallowing study (VFSS) to assess swallow function, inclusive of narrowing within the pharyngoesophageal segment (PES). While differences in the narrowest and widest segments are visualized, the ratio of distention across boluses is not well understood. Method A retrospective review of 50 consecutive VFSSs with five boluses of varied viscosity and volume was performed. Still images at maximal PES distention were captured and scaled using a 19-mm disk. Measurements of the narrowest and widest segments were obtained, and a distention ratio was calculated. Studies were categorized by PES phenotype as normal, esophageal web, cricopharyngeal bar, or narrow PES. PES distention ratios were evaluated across bolus trials and within PES phenotypes using a mixed-methods repeated-measures analysis of variance. Results Of the 50 studies, there were 11 normal, 16 web, 10 bar, and 13 narrow PES. Quantitative differences were present for the narrowest (p = .01) and widest (p = .002) points across bolus volumes. No difference was present in distention ratio (p = .2) across volumes. Evaluating the PES phenotype, web, normal, bar, and narrow PES distention ratios differed (p = .03). Bar and PES narrow distention ratios were lower compared to that of the normal group (p = .01 for normal vs. bar and p = .02 for normal vs. PES narrow). Conclusions PES distention ratio stability across varying bolus volumes and phenotypes suggests that a reduction in trials during a VFSS may permit an equivalent PES evaluation to traditional exams. Ultimately, this could improve our understanding and accurate diagnosis of PES dysfunction.