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Sarcoidosis is an inflammatory granulomatous multi-organ disease of unknown cause. The granulomatous inflammation in sarcoidosis is driven by the interplay between T cells and macrophages. Extracellular vesicles (EVs) play important roles in intercellular communication. Isolated serum EVs from seven patients with sarcoidosis and five control subjects were subjected to non-targeted proteomics analysis. Then 2,292 proteins were detected; 42 proteins were upregulated in patients with sarcoidosis relative to control subjects, and 324 proteins were downregulated. The protein signature of EVs from patients with sarcoidosis reflected disease characteristics such as antigen presentation and immunological disease. Candidate biomarkers were further verified by targeted proteomics analysis in 46 patients and 10 control subjects. CD14 and lipopolysaccharide-binding protein (LBP) were validated by targeted proteomics analysis and upregulation of them was confirmed by immunoblotting. Their expression was also upregulated in macrophages of lung granulomatous lesions. Consistent with these findings, CD14 levels were increased in lipopolysaccharide-stimulated macrophages during multinucleation, concomitant with increased levels of CD14 and LBP in EVs. The area under the curve values of CD14 and LBP were 0.81 and 0.84, respectively. Thus CD14 and LBP in serum EVs, which are associated with granulomatous pathogenesis, can improve the diagnostic accuracy in patients with sarcoidosis.

Background The most important target cell of SARS-CoV-2 is Type II pneumocyte which produces and secretes pulmonary surfactant (PS) that prevents alveolar collapse. PS instillation therapy is dramatically effective for infant respiratory distress syndrome but has been clinically ineffective for ARDS. Nowadays, ARDS is regarded as non-cardiogenic pulmonary edema with vascular hyper-permeability regardless of direct relation to PS dysfunction. However, there is a possibility that this ineffectiveness of PS instillation for ARDS is caused by insufficient delivery. Then, we performed PS instillation simulation with realistic human airway models by the use of computational fluid dynamics, and investigated how instilled PS would move in the liquid layer covering the airway wall and reach to alveolar regions. Methods Two types of 3D human airway models were prepared: one was from the trachea to the lobular bronchi and the other was from a subsegmental bronchus to respiratory bronchioles. The thickness of the liquid layer covering the airway was assigned as 14 % of the inner radius of the airway segment. The liquid layer was assumed to be replaced by an instilled PS. The flow rate of the instilled PS was assigned a constant value, which was determined by the total amount and instillation time in clinical use. The PS concentration of the liquid layer during instillation was computed by solving the advective-diffusion equation. Results The driving pressure from the trachea to respiratory bronchioles was calculated at 317 cmH2O, which is about 20 times of a standard value in conventional PS instillation method where the driving pressure was given by difference between inspiratory and end-expiratory pressures of a ventilator. It means that almost all PS does not reach the alveolar regions but moves to and fro within the airway according to the change in ventilator pressure. The driving pressure from subsegmental bronchus was calculated at 273 cm H2O, that is clinically possible by wedge instillation under bronchoscopic observation. Conclusions The simulation study has revealed that selective wedge instillation under bronchoscopic observation should be tried for COVID-19 pneumonia before the onset of ARDS. It will be also useful for preventing secondary lung fibrosis.

BackgroundDendriform pulmonary ossification (DPO) is a rare condition characterized by metaplastic bone formation in the lung parenchyma. DPO has been reported to be often associated with usual interstitial pneumonia (UIP) or chronic aspiration of gastric acid; however, DPO is believed to be a multifactorial disease, and its clinical features and pathophysiology remain unclear. This study aimed to reveal the novel clinical features and pathophysiology of DPO.MethodsThe pathology reports of consecutive cases diagnosed by surgical lung biopsy for diffuse lung diseases (DLDs) between April 1, 2000 and March 31, 2018 were reviewed retrospectively. Cases showing ossification in their specimens were subsequently reviewed and confirmed as calcified density lesions on CT scans. Besides the definite DPO cases, two DPO cases that involved surgical resection of the lung tumor were also included in the study. The clinical, radiological, and pathological features were analyzed.ResultsThree (0.96 %) out of 313 cases with DLDs were identified as cases of definite DPO. Taken together with the two DPO cases showing lung tumors, five DPO cases were analyzed. The patients were predominantly male, with a median age of 69 years. Four cases showed no smoking history. One patient had gastroesophageal reflux disease and UIP, and another had demonstrable hiatal hernia. Laboratory data were not remarkable. Pulmonary function at baseline was almost normal, and no significant decline was observed during the follow-up period. All cases showed interstitial fibrosis accompanied by ossifications. Intriguingly, the histological examination revealed intra-alveolar fibrosis and slight inflammatory cell infiltration, including new bone formation, corresponding to the consolidation on the CT scan in one case. In addition, consolidation, suspected to be caused by inflammation or hemorrhage, was also noted in two other DPO cases, namely in all of three idiopathic cases without UIP or risk factors for gastric acid aspiration.ConclusionsAll five DPO cases were indolent, indicating that the prognosis of DPO might be good. The pathological and radiological findings suggested the possible involvement of pulmonary inflammation and hemorrhage in the pathogenesis of DPO.