Could the Oxidation of α1-Antitrypsin Prevent the Binding of Human Neutrophil Elastase in COVID-19 Patients?

Human neutrophil elastase (HNE) is involved in SARS-CoV-2 virulence and plays a pivotal role in lung infection of patients infected by COVID-19. In healthy individuals, HNE activity is balanced by α1-antitrypsin (AAT). This is a 52 kDa glycoprotein, mainly produced and secreted by hepatocytes, that specifically inhibits HNE by blocking its activity through the formation of a stable complex (HNE-AAT) in which the two proteins are covalently bound. The lack of this complex, together with the detection of HNE activity in BALf/plasma samples of COVID-19 patients, leads us to hypothesize that potential functional deficiencies should necessarily be attributed to possible structural modifications of AAT. These could greatly diminish its ability to inhibit neutrophil elastase, thus reducing lung protection. The aim of this work was to explore the oxidation state of AAT in BALf/plasma samples from these patients so as to understand whether the deficient inhibitory activity of AAT was somehow related to possible conformational changes caused by the presence of abnormally oxidized residues.

Investigating the Link between Alpha-1 Antitrypsin and Human Neutrophil Elastase in Bronchoalveolar Lavage Fluid of COVID-19 Patients.

Neutrophils play a pathogenic role in COVID-19 by releasing Neutrophils Extracellular Traps (NETs) or human neutrophil elastase (HNE). Given that HNE is inhibited by α1-antitrypsin (AAT), we aimed to assess the content of HNE, α1-antitrypsin (AAT) and HNE-AAT complexes (the AAT/HNE balance) in 33 bronchoalveolar lavage fluid (BALf) samples from COVID-19 patients. These samples were submitted for Gel-Electrophoresis, Western Blot and ELISA, and proteins (bound to AAT or HNE) were identified by Liquid Chromatography-Mass Spectrometry. NETs' release was analyzed by confocal microscopy. Both HNE and AAT were clearly detectable in BALf at high levels. Contrary to what was previously observed in other settings, the formation of HNE-AAT complex was not detected in COVID-19. Rather, HNE was found to be bound to acute phase proteins, histones and C3. Due to the relevant role of NETs, we assessed the ability of free AAT to bind to histones. While confirming this binding, AAT was not able to inhibit NET formation. In conclusion, despite the finding of a high burden of free and bound HNE, the lack of the HNE-AAT inhibitory complex in COVID-19 BALf demonstrates that AAT is not able to block HNE activity. Furthermore, while binding to histones, AAT does not prevent NET formation nor their noxious activity.

Respiratory failure due to concomitant interstitial lung disease and diaphragmatic involvement in a patient with anti-MDA5 dermatomyositis: a case report.

Diaphragm myositis is a rare manifestation of idiopathic inflammatory myopathies, barely portrayed in literature despite its potential severity. We describe a 57-year-old Caucasian male with anti-MDA5 positive dermatomyositis, that had a 4-month history of progressive dyspnoea requiring oxygen-therapy, scarcely responsive to prednisolone. Chest high resolution computed tomography (HRCT) showed mild interstitial lung disease (ILD), whereas pulmonary function tests evidenced severe restrictive syndrome with high lung ultrasound score. Diaphragm ultrasound revealed a marked diaphragm dysmotility, confirmed by electromyography (EMG). The patient was treated with intravenous immunoglobulins and mofetil mycophenolate with progressive improvement of dyspnoea, lung volumes and ILD at CT scan. Ultrasound examination also revealed marked improvement of the diaphragmatic disfunction and a reduction of lung ultrasound score. The use of ultrasound may provide a valuable tool in the diagnosis of diaphragm myositis, which may play a major role in the respiratory impairment of these patients. A combined lung and diaphragm examination allowed bedside monitoring of the improvements in both lung aeration and diaphragm contractility.

Anti-Ro52 antibodies positivity in antisynthetase syndrome: a single centre cohort study.

OBJECTIVES: Although antisynthetase antibodies (ARS) are the established markers of the so-called antisynthetase syndrome (ASSD), in these patients the concomitant positivity of anti-Ro52 antibodies, reported in up to the 50% of cases, is not rare. Several studies focused on the effect of different ARS specificities on the evolution of ASSD, the most recent showing no effects. On the contrary, the role of co-occurring anti-Ro52 antibodies in ASSD is still debated. We investigated the potential of anti-Ro52 antibodies in identifying a clinical phenotype of ASSD or influencing prognosis, irrespectively to the underlying ARS specificity. METHODS: Retrospective analysis of clinical, imaging and laboratory characteristics, therapeutic approaches and outcome at baseline and at last follow-up, of 60 ASSD patients progressively enrolled at our Hospital. RESULTS: We identified 34 anti-Ro+ and 26 anti-Ro- ASSD patients. Classic triad prevalence at baseline was similar between the two groups, whereas interstitial lung disease (ILD) (p value=0.01) and myositis (p value=0.03) were significantly more prevalent in anti-Ro52+ and in anti-Ro52- patients at last follow up, respectively. No differences in therapeutic approaches, oxygen need and ILD patterns were observed. Overall mortality was 25% (15 subjects). No differences in mortality, overall and disease related, between anti-Ro52+ and anti-Ro52- patients were observed (p value=0.764), despite the more frequent ILD occurrence in anti-Ro52+ patients. Survival curves were not different at any time point (Log-rank test, p value 0.98). CONCLUSIONS: Anti-Ro52 antibodies affect time course and clinical characteristics of ASSD. Although ILD is significantly more associated to anti-Ro52 antibodies, no difference in mortality was observed compared to anti-Ro52 negative patients.

A Proof-of-Concept Analysis of Plasma-Derived Exosomal microRNAs in Interstitial Pulmonary Fibrosis Secondary to Antisynthetase Syndrome.

Antisynthetase syndrome (ASSD) is an autoimmune disease characterized by the positivity of autoantibodies against different aminoacyl transfer RNA (tRNA) synthetases. Morbidity and mortality of this disease are highly affected by interstitial lung disease (ILD) which is present in about 80% of patients. In this study, we investigated possible differences in 84 immune-related circulating miRNAs between ASSD patients with and without ILD; we enrolled 15 ASSD patients, 11 with ILD (ILD+) and 4 without ILD (ILD-), and 5 patients with idiopathic pulmonary fibrosis (IPF) as an additional control group. All patients were at disease onset and not on therapy at the time of inclusion. Differentially expressed miRNAs were identified in plasma-derived exosomes, using an miRNA PCR array (MIHS-111ZG, Qiagen, Hilden, Germany); miR-30a-5p and miR-29c-3p were upregulated in ASSD-ILD patients compared to patients without lung involvement (adjusted p-value < 0.05). IPF patients showed higher miR-29c-3p expression levels with respect to both ASSD and ASSD-ILD (p = 0.0005), whereas levels of miR-30a-5p were not different. miR-29c-3p and miR-30a-5p are overexpressed in ASSD-ILD+ patients compared with ILD−. These miRNAs are involved in the regulation of inflammation and fibrosis through their action on NF-κB and TGF-ß1. Although the mechanistic role of these miRNAs in ASSD-ILD development has to be elucidated, we suggest that their exosome levels could be useful in identifying patients at risk of ILD.

Liposomes Loaded with Everolimus and Coated with Hyaluronic Acid: A Promising Approach for Lung Fibrosis.

Chronic lung allograft dysfunction (CLAD) and interstitial lung disease associated with collagen tissue diseases (CTD-ILD) are two end-stage lung disorders in which different chronic triggers induce activation of myo-/fibroblasts (LFs). Everolimus, an mTOR inhibitor, can be adopted as a potential strategy for CLAD and CTD-ILD, however it exerts important side effects. This study aims to exploit nanomedicine to reduce everolimus side effects encapsulating it inside liposomes targeted against LFs, expressing a high rate of CD44. PEGylated liposomes were modified with high molecular weight hyaluronic acid and loaded with everolimus (PEG-LIP(ev)-HA400kDa). Liposomes were tested by in vitro experiments using LFs derived from broncholveolar lavage (BAL) of patients affected by CLAD and CTD-ILD, and on alveolar macrophages (AM) and lymphocytes isolated, respectively, from BAL and peripheral blood. PEG-LIP-HA400kDa demonstrated to be specific for LFs, but not for CD44-negative cells, and after loading everolimus, PEG-LIP(ev)-HA400kDa were able to arrest cell cycle arrest and to decrease phospho-mTOR level. PEG-LIP(ev)-HA400kDa showed anti-inflammatory effect on immune cells. This study opens the possibility to use everolimus in lung fibrotic diseases, demonstrating that our lipids-based vehicles can vehicle everolimus inside cells exerting the same drug molecular effect, not only in LFs, but also in immune cells.

Prolonged Low-Dose Methylprednisolone in Patients With Severe COVID-19 Pneumonia.

BACKGROUND: In hospitalized patients with coronavirus disease 2019 (COVID-19) pneumonia, progression to acute respiratory failure requiring invasive mechanical ventilation (MV) is associated with significant morbidity and mortality. Severe dysregulated systemic inflammation is the putative mechanism. We hypothesize that early prolonged methylprednisolone (MP) treatment could accelerate disease resolution, decreasing the need for intensive care unit (ICU) admission and mortality. METHODS: We conducted a multicenter observational study to explore the association between exposure to prolonged, low-dose MP treatment and need for ICU referral, intubation, or death within 28 days (composite primary end point) in patients with severe COVID-19 pneumonia admitted to Italian respiratory high-dependency units. Secondary outcomes were invasive MV-free days and changes in C-reactive protein (CRP) levels. RESULTS: Findings are reported as MP (n = 83) vs control (n = 90). The composite primary end point was met by 19 vs 40 (adjusted hazard ratio [aHR], 0.41; 95% CI, 0.24-0.72). Transfer to ICU and invasive MV were necessary in 15 vs 27 (P = .07) and 14 vs 26 (P = .10), respectively. By day 28, the MP group had fewer deaths (6 vs 21; aHR, 0.29; 95% CI, 0.12-0.73) and more days off invasive MV (24.0 ±â€…9.0 vs 17.5 ±â€…12.8; P = .001). Study treatment was associated with rapid improvement in PaO2:FiO2 and CRP levels. The complication rate was similar for the 2 groups (P = .84). CONCLUSION: In patients with severe COVID-19 pneumonia, early administration of prolonged MP treatment was associated with a significantly lower hazard of death (71%) and decreased ventilator dependence. Treatment was safe and did not impact viral clearance. A large randomized controlled trial (RECOVERY trial) has been performed that validates these findings. Clinical trial registration. ClinicalTrials.gov NCT04323592.