Chronic obstructive pulmonary disease (COPD) is a progressive condition of chronic bronchitis, small airway obstruction, and emphysema that represents a leading cause of death worldwide. While inflammation, fibrosis, mucus hypersecretion, and metaplastic epithelial lesions are hallmarks of this disease, their origins and dependent relationships remain unclear. Here we apply single-cell cloning technologies to lung tissue of patients with and without COPD. Unlike control lungs, which were dominated by normal distal airway progenitor cells, COPD lungs were inundated by three variant progenitors epigenetically committed to distinct metaplastic lesions. When transplanted to immunodeficient mice, these variant clones induced pathology akin to the mucous and squamous metaplasia, neutrophilic inflammation, and fibrosis seen in COPD. Remarkably, similar variants pre-exist as minor constituents of control and fetal lung and conceivably act in normal processes of immune surveillance. However, these same variants likely catalyze the pathologic and progressive features of COPD when expanded to high numbers.

Summary/Abstract The ability to replace defective cells in an airway with cells that can engraft, integrate and restore a functional epithelium could potentially cure a number of lung diseases. Progress toward the development of strategies to regenerate the adult lung by either in vivo or ex vivo targeting of endogenous stem cells or pluripotent stem cell derivatives, is limited by our fundamental lack of understanding of the mechanisms controlling human lung development, the precise identity and function of human lung stem and progenitor cell types, and the genetic and epigenetic control of human lung fate. In this review, we intend to discuss the known stem/progenitor cell populations, their relative differences between rodents and humans, their roles in chronic lung disease, and their therapeutic prospects. Additionally, we highlight the recent breakthroughs that have increased our understanding of these cell types. These advancements include novel lineage-traced animal models and single-cell RNA sequencing of human airway cells, which have provided critical information on the stem cell subtypes, transition states, identifying cell markers, and intricate pathways that commit a stem cell to differentiate or to maintain plasticity. As our capacity to model the human lung evolves, so will our understanding of lung regeneration and our ability to target endogenous stem cells as a therapeutic approach for lung disease.

Background/Aims: Peroral endoscopic myotomy (POEM) is a novel procedure for the treatment of achalasia and spastic esophageal disorders. Experience with POEM is limited, but its reported outcomes are excellent. It is deemed safe even for patients with prior interventions. Methods: This retrospective review included patients who underwent POEM at a tertiary US center. POEM was performed in a multidisciplinary approach by advanced endoscopists and foregut surgeons. Clinical success was defined as a post-POEM Eckardt score ≤3. Results: A total of 125 patients were included. Median follow-up period was 18 months (interquartile range, 10-22 months). Clinical success was achieved in 92% of patients and persisted at 12 months in 88% of patients. Mucosal barrier failure (MBF) occurred in 7 patients, 2 of whom required surgical intervention. MBF was more common in patients with prior laparoscopic Heller myotomy (19% vs. 3%, p=0.015). MBF requiring surgical intervention occurred early in the learning curve. Conclusions: POEM is safe and effective in the treatment of achalasia and spastic esophageal disorders even after failed prior interventions.

Background: The optimal surgery for resectable pulmonary typical carcinoid (TC), e.g., lobar resection (L-R) vs. sub-lobar resection (SL-R), is controversial. This is further explored in this population-based study. Methods: The Surveillance, Epidemiology, and End Results (SEER) Program was used to select patients ≥66 years old, and diagnosed between 2000 and 2012 with pulmonary TC. A similar cohort was developed using the SEER-Medicare database (diagnosed from 2000−2007) to identify chemotherapy (CTX) use and co-morbidity. Five-year survival was calculated using univariate and multivariate analysis. Results: A total of 1,506 and 512 patients were identified from SEER and SEER-Medicare, respectively. In the SEER cohort, 49%, 29% and 21% received L-R, SL-R, and no surgery (NS), respectively. Those who received NS were older (P<0.001), had a higher stage (P<0.001), greater comorbidity (P<0.001), and were more likely to receive radiotherapy (XRT) (P<0.001) and CTX (P<0.001). Relative survival was nearly 100%

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