Circulating miRNAs as Promising Biomarkers to Evaluate ECMO Treatment Responses in ARDS Patients

Abstract

The use of extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS) has increased in the last decade. However, mortality remains high, and the complexity of ECMO requires individualized treatment. There are some biomarkers to monitor progression and predict clinical outcomes of ARDS. This project aims to advance the management of ARDS patients treated with ECMO by exploring miRNA expression in whole blood. The analysis was conducted on two groups with different length of ECMO: Group A (longer runs) and group B (shorter runs). We analyzed miRNAs before ECMO cannulation, and at 7 and 14 days of ECMO support. Our results showed that in the group B patients, 11 deregulated miRNAs were identified, and showed an opposite trend of expression compared to the group A patients. In silico analysis revealed that these 11 miRNAs were related to processes involved in the pathogenesis and evolution of ARDS. This scenario could represent homeostatic mechanisms by which, in ECMO responsive patients, pathways activated during ARDS progression are switched-off. Circulating miRNAs could represent promising biomarkers to monitor the evolution of ARDS under ECMO support. Further studies may shed light on this topic to improve a personalized approach in such a complex setting of patients.

Keywords: ARDS; ECMO; biomarkers; miRNAs.

Figure 1

RT-PCR analysis of miRNAs in ARDS patients supported with ECMO for 14 days. (a) Volcano plot analysis (p ≤ 0.05) plot analysis of RNAs in ARDS patients supported with ECMO group A patients after 7 and (b) 14 days of ECMO support. (c) Up-regulated miRNAs in group A patients after 7 and 14 days of ECMO support. (d) Volcano plot analysis (p ≤ 0.05 and fold change ≥ 0) of deregulated miRNAs analyzed in group B patients after 7 and (e) 14 days of ECMO support. (f) Up- and down-regulated miRNAs in group B patients after 7 and 14 days of ECMO support. miRNA levels were normalized to those of U6. Data are means ± SD. (Comparisons made by Student’s t-test). * p < 0.05 vs. pre-ECMO (patients before cannulation).

Figure 2

Blood expression levels of thirteen miRNAs in group A and group B patients after 7 and 14 days of ECMO support. Data are presented as expression relative to U6. Box plots are displayed where the horizontal bar represents the median, the box represents the IQR, and the whiskers represent the maximum and minimum values. Comparisons were made by Mann–Whitney U test. * p < 0.05.

Figure 3

GO analysis of eleven miRNAs deregulated in group B patients. Partial list of biological process enrichment analysis.

Figure 4

Protein–protein interaction network generated for shared miRNA target genes after miRNET analysis. Top images show networks with all interactions between deregulated miRNAs and genes involved in tissue remodeling, regulation of the immune system and regulation of coagulation. Bottom images show schematic representation of crucial proteins involved in the regulation of each pathway and their interaction with some deregulated miRNAs.

Figure 5

Temporal expression of miRNAs after 7 and 14 days of ECMO support in group A and in group B patients. Data shown are mean values ± SE of miRNA expression of 10 patients for each time point.

Figure 6

Hierarchical clustering analysis based on eight selected miRNA expression levels in ARDS patients supported with ECMO for 14 days. Heatmap colors represent relative miRNA expression normalized to housekeeping.

Figure 7

ROC curves of the diagnostic potential of the individual blood miRNAs (miR-200b-3p, miR-1271-5p, miR-566, miR-328-3p, miR-432-5p, miR-25-5p, let-7f-5p and miR-708-5p) after 14 days of ECMO support discriminating between group A and group B patients. ROC curves were made with values of relative expression of each miRNA at 14 days of ECMO support. The area under curve (AUC) values ranged from 0.52 to 0.92.