The extracellular calcium-sensing receptor regulates human fetal lung development via CFTR

Optimal fetal lung growth requires anion-driven fluid secretion into the lumen of the developing organ. The fetus is hypercalcemic compared to the mother and here we show that in the developing human lung this hypercalcaemia acts on the extracellular calcium-sensing receptor, CaSR, to promote fluid-driven lung expansion through activation of the cystic fibrosis transmembrane conductance regulator, CFTR. Several chloride channels including TMEM16, bestrophin, CFTR, CLCN2 and CLCA1, are also expressed in the developing human fetal lung at gestational stages when CaSR expression is maximal. Measurements of Cl−-driven fluid secretion in organ explant cultures show that pharmacological CaSR activation by calcimimetics stimulates lung fluid secretion through CFTR, an effect which in humans, but not mice, was also mimicked by fetal hypercalcemic conditions, demonstrating that the physiological relevance of such a mechanism appears to be species-specific. Calcimimetics promote CFTR opening by activating adenylate cyclase and we show that Ca2+-stimulated type I adenylate cyclase is expressed in the developing human lung. Together, these observations suggest that physiological fetal hypercalcemia, acting on the CaSR, promotes human fetal lung development via cAMP-dependent opening of CFTR. Disturbances in this process would be expected to permanently impact lung structure and might predispose to certain postnatal respiratory disease

Impact of computed tomographic patterns and extent on clinical management and outcomes of patients with organising pneumonia

Background Organising pneumonia (OP) has variable clinical and radiographic presentations and unstandardised treatments. Most patients with OP have favourable outcomes, but some develop respiratory insufficiency, experience recurrence or die. In this study we investigated the impact of computed tomographic (CT) patterns and extent of OP on the diagnostic and therapeutic management that patients received, and that on the therapeutic response and prognosis (particularly the risk of respiratory insufficiency and death). Methods We retrospectively studied 156 patients with OP followed at our hospital between 2010 and 2021. The diagnosis was confirmed histologically and verified by multidisciplinary specialists. We performed Firth's logistic regression to determine the relationship between CT features and aetiologies, management and outcomes including the risk of severe disease (defined as the need for supplemental oxygen or mechanical ventilation). We conducted Kaplan–Meier analyses to assess survival differences. Results Patients exhibiting multilobe involvement or mixed patterns, or both, were more likely to have secondary OP and receive immunosuppressants. Higher proportions of these patients experienced recurrence. Compared to patients with single-lobe involvement and single-pattern, they also had an enhanced risk of severe disease (the adjusted odds ratio for patients who simultaneously had multilobe involvement and mixed patterns was 27.64; 95% confidence interval 8.25–127.44). Besides, these patients had decreased survival probabilities. Conclusion Different CT features of OP impact patients’ management and prognosis. When treating patients with OP exhibiting multilobe involvement or mixed patterns, or both, it is important to identify the possible causative aetiology and follow closely for adverse outcomes