Noninvasive biomarkers for the detection of GERD-induced pulmonary injury.

BACKGROUND: The role of gastroesophageal reflux in progressive lung damage is increasingly recognized. We have proposed, based on our work with lung transplant recipients, a novel immune mechanism of pulmonary injury after aspiration of gastric contents, during which higher levels of normally sequestered lung self-antigens (SAgs) collagen V (Col-V) and K-alpha-1 tubulin (Kα1T) in circulating small extracellular vesicles (EVs) induce the production of self-antibodies (SAbs) anti-Col-V and anti-Kα1T. Thus, we aimed to determine whether levels of SAbs or SAgs increased in an animal model of aspiration-induced lung damage in a nontransplant setting. METHODS: We created a murine model of repetitive lung aspiration using C57BL/6J mice. Mice were aspirated weekly with 1 mL/kg of hydrochloric acid (n = 9), human gastric contents (n = 9), or combined (1:1) fluid (n = 9) once, three, or six times (n = 3 in each subgroup; control group, n = 9). Blood samples were periodically obtained, and all animals were sacrificed at day 90 for pathological assessment. SAbs were measured using an enzyme-linked immunosorbent assay; SAgs and NF-κB contained in small EVs were assessed by western blot. RESULTS: Aspirated mice weighed significantly less than controls throughout the study and had histological evidence of pulmonary injury at day 90. Overall, aspirated mice developed higher concentrations of anti-Col-V at day 28 (53.9 ± 28.7 vs. 29.9 ± 4.5 ng/mL, p < 0.01), day 35 (42.6 ± 19.8 vs. 28.6 ± 7.2 ng/mL, p = 0.038), and day 90 (59.7 ± 27.7 vs. 34.1 ± 3.2 ng/mL, p = 0.014) than the control group. Circulating small EVs isolated from aspirated mice on day 90 contained higher levels of Col-V (0.7 ± 0.56 vs. 0.18 ± 0.6 m.o.d., p = 0.009) and NF-κB (0.42 ± 0.27 vs. 0.27 ± 0.09 m.o.d., p = 0.095) than those from controls. CONCLUSIONS: This experimental study supports the theory that gastroesophageal reflux leads to the development of lung damage and an increase of humoral markers that may serve as noninvasive biomarkers to detect asymptomatic lung injury among patients with gastroesophageal reflux disease.

Incidentally Detected Malignancies in Lung Explants.

Introduction: Incidentally detected malignancies in lung explants portend risk of early cancer recurrence and metastases with posttransplant immunosuppression. We present a series of lung transplant recipients with previously unverified malignancies in native lung explants. Design: We reviewed the histopathology, radiographic imaging, and management of lung explant malignancies at our institution over 10 years (2011-2020). Endpoints were survival and allograft rejection. Results: An explant malignancy was found in 1.3% (11/855) of lung transplant recipients (6 [55%] men; median age 68 years; 6 [55%] ex-smokers [median pack-years, 25]). Nine (82%) were adenocarcinoma, 1 (9%) was squamous cell carcinoma (SCC), and 1 (9%) was follicular lymphoma. Three patients (27%) had multifocal involvement (≥3 lobes), 4 (36%) had nodal involvement, and the median (range) tumor size was 2.7 (0.4-19) cm. The median interval between last imaging and transplant was 58 (29-144) days. Mycophenolate mofetil was discontinued or reduced in all; everolimus was used in 2 patients, and cisplatin-pemetrexed chemotherapy was used in 2 patients. The prevalence of acute cellular rejection and chronic rejection was 27% and 9%, respectively. Lung recipients with cancer had significantly lower survival than those without (36.4% vs 67.3%, p = 0.002); median survival was 27 (17, 65) months in 4 recipients who were alive and cancer-free at the end of the study period. Conclusions: Unidentified malignancies, commonly adenocarcinoma, can be detected in explanted native lungs. Pneumonectomy may be curative in SCC, lymphoproliferative disorders, and stage I adenocarcinoma. Modulating immunosuppression to prevent allograft rejection and tumor proliferation is warranted.

Incidental Finding of a Large Right Atrial Thrombus in a Patient With Cerebral Lymphoma.

Right atrial (RA) masses are rare, challenging to diagnose, and potentially life-threatening with high mortality if untreated. We present a patient presenting with diffuse large B-cell lymphoma in the brain that was incidentally found to have a large RA mass. For a better definition of the RA mass, extensive workup using multimodality imaging including chest computed tomography, transthoracic echocardiography, transesophageal echocardiography, cardiac magnetic resonance imaging, and left heart catheterization was warranted. The imaging demonstrated a large RA mass extending through the tricuspid valve into the right ventricle and superior and inferior vena cava without a mobile component. The mass was then successfully resected, and further histology examination was performed to rule out lymphoma and rare subtypes of diffuse large B-cell lymphoma. The comprehensive workup proved the RA mass to be a calcified thrombus rather than a direct metastatic spread of lymphoma.