American journal of respiratory and critical care medicine
-
Am. J. Respir. Crit. Care Med. · Sep 2024
Randomized Controlled Trial Observational StudyPotential Diaphragm Muscle Weakness-related Dyspnea Persists Two Years after COVID-19 and Could Be Improved by Inspiratory Muscle Training: Results of an Observational and an Interventional Trial.
Rationale: Diaphragm muscle weakness might underlie persistent exertional dyspnea, despite normal lung and cardiac function in individuals who were previously hospitalized for acute coronavirus disease (COVID-19) illness. Objectives: The authors sought, first, to determine the persistence and pathophysiological nature of diaphragm muscle weakness and its association with exertional dyspnea 2 years after hospitalization for COVID-19 and, second, to investigate the impact of inspiratory muscle training (IMT) on diaphragm and inspiratory muscle weakness and exertional dyspnea in individuals with long COVID. Methods: Approximately 2 years after hospitalization for COVID-19, 30 individuals (11 women, 19 men; median age, 58 years; interquartile range [IQR] = 51-63) underwent comprehensive (invasive) respiratory muscle assessment and evaluation of dyspnea. ⋯ Improvements persisted for 6 weeks after IMT completion. Conclusions: To the best of the authors' knowledge, this study is the first to identify a potential treatment for persisting exertional dyspnea in long COVID and provide a possible pathophysiological explanation for the treatment benefit. Clinical trial registered with www.clinicaltrials.gov (NCT04854863, NCT05582642).
-
Am. J. Respir. Crit. Care Med. · Sep 2024
Disrupted BMP-9 Signaling Impairs Pulmonary Vascular Integrity in Hepatopulmonary Syndrome.
Rationale: Hepatopulmonary syndrome (HPS) is a severe complication of liver diseases characterized by abnormal dilation of pulmonary vessels, resulting in impaired oxygenation. Recent research highlights the pivotal role of liver-produced BMP-9 (bone morphogenetic protein-9) in maintaining pulmonary vascular integrity. Objectives: This study aimed to investigate the involvement of BMP-9 in human and experimental HPS. ⋯ Daily treatment with FK506 for 2 weeks restored the BMP pathway in the lungs, alleviating intrapulmonary vascular dilations and improving gas exchange impairment. Furthermore, BMP-9-knockout rats displayed a pulmonary HPS phenotype, supporting its role in disease progression. Conclusions: The study findings suggest that portal hypertension-induced loss of BMP-9 signaling contributes to HPS development.