# Transcriptomic analysis of circulating extracellular vesicles during the perioperative period of Fontan and Glenn surgery

## TL;DR

This study explores RNA biomarkers in blood vesicles before and after heart surgeries to improve diagnosis of long-term complications.

## Contribution

The study identifies novel RNA biomarkers in extracellular vesicles that could predict outcomes in patients undergoing Fontan and Glenn surgeries.

## Key findings

- Post-op sEVs show increased pro-angiogenic cargo compared to pre-op sEVs.
- Fontan post-op sEVs induce a stronger pro-angiogenic response in wound healing assays.
- Key transcripts like MAPK6 and hsa-miR-340-5p are linked to the observed wound healing response.

## Abstract

Single-ventricle defects are treated with the Glenn and Fontan procedures, which offer lifesaving relief but result in lifelong complications. To address the lack of outcome predictors, we conducted an untargeted transcriptomic analysis to identify RNA biomarkers in serum and circulating sEVs from 25 Glenn or Fontan patients with three samples exclusively used for experimental assays. Unsupervised analysis revealed a distinction between pre-op and post-op samples in both surgical groups. Differential gene expression and pathway analysis showed enrichment for pro-angiogenic cargo in post-op sEVs compared to pre-op sEVs. Wound healing assays revealed post-op Fontan sEVs induce a stronger pro-angiogenic response than pre-op Fontan sEVs. A PLSR-guided approach revealed MAPK6, GLE1, hsa-miR-340-5p, and hsa-miR-199b-5p as key transcripts in the observed wound healing response. Lastly, EV-Origin revealed decreased secretion of sEV from cardiac tissue and increased secretion from brain tissue for both Fontan and Glenn samples. This work demonstrates the potential of sEV RNAs as biomarkers for patients with Fontan physiology, enabling quicker diagnosis for Fontan-associated complications.