N-acetylcysteine and azithromycin affect the innate immune response in cystic fibrosis bronchial epithelial cells in vitro.

BACKGROUND AND OBJECTIVE: We have previously reported that N-acetylcysteine (NAC), ambroxol and azithromycin (AZM) (partially) correct the chloride efflux dysfunction in cystic fibrosis bronchial epithelial (CFBE) cells with the ΔF508 homozygous mutation in vitro. METHODS: In the present paper, we further investigated possible immunomodulatory effects of these drugs on the regulation of the innate immune system by studying the expression of the cytosolic NOD-like receptors NLRC1 and NLRC2, and interleukin (IL)-6 production in CFBE cells. RESULTS: Under basal conditions, PCR and Western Blot data indicate that the NLRC2 receptor has a reduced expression in CF cells as compared to non-CF (16HBE) cells, but that the NLRC1 expression is the same in both cell lines. AZM significantly upregulated NLRC1 and NLRC2 while NAC upregulated only NLRC2 receptor expression in CF cells. Reduced basal IL-6 production was found in CF cells as compared to non-CF cells. MDP (an NLRC2 agonist), NAC and AZM, but not Tri-DAP (an NLRC1 agonist), increased IL-6 production in CF cells, indicating that in CF cells IL-6 upregulation is independent of NLRC1, but involves the activation of NLRC2. CONCLUSION: Overall, the results indicate that NAC and AZM not only can correct the chloride efflux dysfunction but also have a weakly strengthening effect on the innate immune system.

The effect of ambroxol on chloride transport, CFTR and ENaC in cystic fibrosis airway epithelial cells.

Ambroxol, a mucokinetic anti-inflammatory drug, has been used for treatment of cystic fibrosis (CF). The respiratory epithelium is covered by the airway surface liquid (ASL), the thickness and composition of which is determined by Cl(-) efflux via the cystic fibrosis transmembrane conductance regulator (CFTR) and Na(+) influx via the epithelial Na(+) channel (ENaC). In cells expressing wt-CFTR, ambroxol increased the Cl(-) conductance, but not the bicarbonate conductance of the CFTR channels. We investigated whether treatment with ambroxol enhances chloride transport and/or CFTR and ENaC expression in CF airway epithelial cells (CFBE) cells. CFBE cells were treated with 100 µM ambroxol for 2, 4 or 8 h. mRNA expression for CFTR and ENaC subunits was analysed by real-time polymerase chain reaction (RT-PCR); protein expression was measured by Western blot. The effect of ambroxol on Cl(-) transport was measured by Cl(-) efflux measurements with a fluorescent chloride probe. Ambroxol significantly stimulated Cl(-) efflux from CFBE cells (a sixfold increase after 8 h treatment), and enhanced the expression of the mRNA of CFTR and α-ENaC, and of the CFTR protein. No significant difference was observed in ß-ENaC after exposure to ambroxol, whereas mRNA expression of γ-ENaC was reduced. No significant effects of ambroxol on the ENaC subunits were observed by Western blot. Ambroxol did not significantly affect the intracellular Ca(2+) concentration. Upregulation of CFTR and enhanced Cl(-) efflux after ambroxol treatment should promote transepithelial ion and water transport, which may improve hydration of the mucus, and therefore be beneficial to CF-patients.

Fulminant myocarditis in a COVID-19 positive patient treated with mechanical circulatory support - a case report.

BACKGROUND: Coronavirus disease 2019 (COVID-19) spreading from Wuhan, Hubei province in China, is an expanding global pandemic with significant morbidity and mortality. Even though respiratory failure is the cardinal form of severe COVID-19, concomitant cardiac involvement is common. Myocarditis is a challenging diagnosis due to heterogeneity of clinical presentation, ranging from mild symptoms to fatal arrhythmia and cardiogenic shock (CS). The aetiology is often viral and endomyocardial biopsy (EMB) is the gold standard for definite myocarditis. However, the diagnosis is often made on medical history, clinical presentation, magnetic resonance imaging, and blood tests. CASE SUMMARY: We present a 43-year-old man with mixed connective tissue disease treated with hydroxychloroquine who rapidly developed CS 4 days from symptom onset with fever and cough, showing positive polymerase chain reaction nasopharyngeal swab for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. While computed tomography of the thorax was normal, high-sensitivity troponin T was elevated and electrocardiogram showed diffuse ST elevation and low voltage as signs of myocardial oedema. Echocardiography showed severe depression of left ventricular function. The myocardium recovered completely after a week with mechanical circulatory support (MCS). EMB was performed but could neither identify the virus in the cardiomyocytes, nor signs of inflammation. Still the most probable aetiology of CS in this case is myocarditis as a sole symptom of COVID-19. DISCUSSION: COVID-19 patients in need of hospitalization present commonly with respiratory manifestations. We present the first case of fulminant myocarditis rapidly progressing to CS in a COVID-19 patient without respiratory failure, successfully treated with inotropes and MCS.

The effect of N-acetylcysteine on chloride efflux from airway epithelial cells.

Defective chloride transport in epithelial cells increases mucus viscosity and leads to recurrent infections with high oxidative stress in patients with CF (cystic fibrosis). NAC (N-acetylcysteine) is a well known mucolytic and antioxidant drug, and an indirect precursor of glutathione. Since GSNO (S-nitrosoglutathione) previously has been shown to be able to promote Cl- efflux from CF airway epithelial cells, it was investigated whether NAC also could stimulate Cl- efflux from CF and non-CF epithelial cells and through which mechanisms. CFBE (CF bronchial epithelial cells) and normal bronchial epithelial cells (16HBE) were treated with 1 mM, 5 mM, 10 mM or 15 mM NAC for 4 h at 37 degrees C. The effect of NAC on Cl- transport was measured by Cl- efflux measurements and by X-ray microanalysis. Cl- efflux from CFBE cells was stimulated by NAC in a dose-dependent manner, with 10 mM NAC causing a significant increase in Cl- efflux with nearly 80% in CFBE cells. The intracellular Cl- concentration in CFBE cells was significantly decreased up to 60% after 4 h treatment with 10 mM NAC. Moreover immunocytochemistry and Western blot experiments revealed expression of CFTR channel on CFBE cells after treatment with 10 mM NAC. The stimulation of Cl- efflux by NAC in CF airway epithelial cells may improve hydration of the mucus and thereby be beneficial for CF patients.

Azithromycin increases chloride efflux from cystic fibrosis airway epithelial cells.

It was investigated whether azithromycin (AZM) stimulates chloride (Cl-) efflux from cystic fibrosis (CF) and non-CF airway epithelial cells, possibly secondary to up-regulation of the multidrug resistance protein (MDR). CF and non-CF human airway epithelial cell lines (CFBE and 16HBE) were treated with 0.4, 4, and 40 microg/mL AZM for 4 days. Cl- efflux was explored in the presence or absence of specific inhibitors of CFTR and alternative Cl- channels. Six CF patients received AZM (500 mg daily) for 6 months. The percentage of predicted forced vital capacity (FVC%), forced expiratory volume (FEV1%), and the number of acute exacerbations were compared before and after treatment. Nasal biopsies were taken before and after treatment, and mRNA expression of MDR and CFTR was determined by in situ hybridization. A significant dose-dependent increase of Cl- efflux from CFBE cells (but not from 16HBE cells) was observed after AZM treatment. A CFTR inhibitor significantly reduced AZM-stimulated Cl- efflux from CFBE cells. A significant improvement in FEV1%, and fewer exacerbations were observed. AZM treatment did not affect mRNA expression of MDR and CFTR. The stimulation of Cl- efflux could be part of the explanation for the clinical improvement seen among the patients.

Effect of duramycin on chloride transport and intracellular calcium concentration in cystic fibrosis and non-cystic fibrosis epithelia.

The lantibiotic duramycin (Moli1901, Lancovutide) has been suggested as a drug of choice in the treatment for cystic fibrosis (CF). It has been proposed that duramycin may stimulate chloride secretion through Ca²(+) -activated Cl⁻ channels (CaCC). We investigated whether duramycin exhibited any effect on Cl⁻ efflux and intracellular Ca²(+) concentration ([Ca²(+)](i)) in CF and non-CF epithelial cells. Duramycin did stimulate Cl⁻ efflux from CF bronchial epithelial cells (CFBE) in a narrow concentration range (around 1 µM). However, 100 and 250 µM of duramycin inhibited Cl⁻ efflux from CFBE cells. An inhibitor of the CF transmembrane conductance regulator (CFTR(inh)₋172) and a blocker of the capacitative Ca²(+) entry, gadolinium chloride, inhibited the duramycin-induced Cl⁻ efflux. No effect on Cl⁻ efflux was observed in non-CF human bronchial epithelial cells (16HBE), human airway submucosal gland cell line, human pancreatic epithelial cells, CF airway submucosal gland epithelial cells, and CF pancreatic cells. The [Ca²(+)](i) was increased by 3 µM duramycin in 16HBE cells, but decreased after 1, and 3 µM of duramycin in CFBE cells. The results suggest that the mechanism responsible for the stimulation of Cl⁻ efflux by duramycin is mainly related to unspecific changes of the cell membrane or its components rather than to effects on CaCC.