POS0426 CIRCULATING MICRORNA PROFILING IN PATIENTS WITH ANTI-SYNTHETASE SYNDROME AND INTERSTITIAL LUNG DISEASE

Background:

Anti-synthetase syndrome (ASSD) is an autoimmune disease characterized by autoantibodies against one of many aminoacyl transfer RNA (tRNA) synthetases. Interstitial Lung Disease (ILD) in ASSD patients is frequent, often severe and rapidly progressive, causing much of the increased morbidity and mortality associated with ASSD as compared to other idiopathic inflammatory myopathies [1].

Objectives:

In this study, we hypothesized that immune-related miRNAs may be associated with presence/absence of lung involvement in patients with ASSD and help predict disease course.

Methods:

A total of 15 ASSD patients were enrolled: 11 with ILD and 4 without ILD. Differentially expressed miRNAs were identified in plasma derived-exosome, using miRNA PCR array (MIHS-111ZG, Qiagen) including 84 miRNAs involved in activation and differentiation of T and B cells.

Results:

Among all miRNAs analyzed we found that miR-15b-5p, miR-23a-3p, miR-25-3p, miR-30a-5p and miR29c-3p were up-regulated in ASSD-ILD patients (p<0.05) as compared to patients without lung involvement (Figure 1). To evaluate the effectiveness of the five miRNAs for predicting ILD among ASSD patients, ROC curves were constructed. The AUCs of miR-15b-5p, miR-25-3p, miR-30a-5p and miR29c-3p were 0.83, 0.87, 0.86 and 0.89, respectively (p= 0.05 for miR-25-3p and p<0.05 for all other curves). The prediction of the biologic targets and pathways as well as cellular processes by DIANA-mirPath analysis showed that all miRNAs associated with ILD presence are involved in PI3K-Akt signaling pathway.

Conclusion:

Our study shows that, in ASSD patients with ILD, miR-15b-5p, miR-23a-3p, miR-25-3p, miR-30a-5p and miR29c-3p were up-regulated compared to patients without evidence of ILD. A clear involvement in immune and inflammatory diseases was documented for the miRNAs identified [2] and, for many of these, studies in the literature indicate a possible role in pulmonary fibrosis [3]. It is notable that these miRNAs were related to PI3K-Akt signaling pathway that regulate cell proliferation, differentiation and apoptosis [4]. It has also been demonstrated that in lung fibroblast the PI3K–Akt signals can be aberrantly activated [5]. The identification of markers could be important in the early identification of the disease and for its treatment.

References:

[1]Kalluri M, Oddis CV. Pulmonary manifestations of the idiopathic inflammatory myopathies. Clinics in chest medicine. 2010; 31:501–512.

[2]Prabahar A, Natarajan J, ImmunemiR-a database of prioritized immune miRNA disease associations and its interactome. MicroRNA, 2017; 6: 71–78.

[3]Sessa R, Hata A. Role of microRNAs in lung development and pulmonary diseases. Pulm Circ. 2013; 3:315-28.

[4]Ersahin T, Tuncbag N, Cetin-Atalay R. The PI3K/AKT/mTOR interactive pathway. Mol Biosyst. 2015;11:1946-54.

[5]Zhang XL, Xing RG, Chen L, Liu CR, Miao ZG. PI3K/Akt signaling is involved in the pathogenesis of bleomycin-induced pulmonary fibrosis via regulation of epithelial-mesenchymal transition. Mol Med Rep. 2016;14:5699-5706.

Figure 1.

Comparison of relative levels of five miRNAs among patients with and without lung involvement were expressed as log2 transformed values. *p<0.05; **p<0.01

Disclosure of Interests:

None declared

Hypoalbuminemia in COVID-19: assessing the hypothesis for underlying pulmonary capillary leakage

BACKGROUND

Since the first observations of patients with COVID-19, significant hypoalbuminaemia was detected. Its causes have not been investigated yet.

OBJECTIVE

We hypothesized that pulmonary capillary leakage affects the severity of respiratory failure, causing a shift of fluids and proteins through the epithelial-endothelial barrier.

METHODS

One hundred seventy-four COVID-19 patients with respiratory symptoms, 92 admitted to the intermediate medicine ward (IMW) and 82 to the intensive care unit (ICU) at Luigi Sacco Hospital in Milan, were studied.

RESULTS

Baseline characteristics at admission were considered. Proteins, interleukin 8 (IL-8) and interleukin 10 (IL-10) in bronchoalveolar lavage fluid (BALF) were analysed in 26 ICU patients. In addition, ten autopsy ultrastructural lung studies were performed in patients with COVID-19 and compared with postmortem findings in a control group (bacterial pneumonia-ARDS and H1N1-ARDS). ICU patients had lower serum albumin than IMW patients [20 (18-23) vs 28 (24-33) g L^-1 , P < 0.001]. Serum albumin was lower in more compromised groups (lower PaO₂ -to-FiO₂ ratio and worst chest X-ray findings) and was associated with 30 days of probability of survival. Protein concentration was correlated with IL-8 and IL-10 levels in BALF. Electron microscopy examinations of eight out of ten COVID-19 lung tissues showed loosening of junctional complexes, quantitatively more pronounced than in controls, and direct viral infection of type 2 pneumocytes and endothelial cells.

CONCLUSION

Hypoalbuminaemia may serve as severity marker of epithelial-endothelial damage in patients with COVID-19. There are clues that pulmonary capillary leak syndrome plays a key role in the pathogenesis of COVID-19 and might be a potential therapeutic target.