# Cargo Analysis and MRI‐Based Therapeutic Assessment of Iron Oxide Labelled Extracellular Vesicles of Hypoxia Human Stem Cells in Ischemic Stroke

## TL;DR

This study explores how iron oxide-labeled extracellular vesicles from hypoxia-treated human stem cells can help treat ischemic stroke, showing promising therapeutic effects in a preclinical model.

## Contribution

The study introduces a novel approach using hypoxia preconditioned stem cell-derived extracellular vesicles for stroke therapy, supported by MRI-based therapeutic assessment.

## Key findings

- Hypoxia preconditioning increased extracellular vesicle yield by 57% without altering size or exosomal markers.
- EVs from hypoxia-treated hMSCs localized to ischemic lesions and improved recovery in stroke models.
- MRI tracking showed differential recovery in sodium and lactate levels following EV administration.

## Abstract

Human mesenchymal stem cells (hMSCs) have been under investigation in preclinical and clinical settings for treating neurological disorders in recent years. Predominantly due to paracrine effects in vivo, hMSC‐secreted extracellular vesicles (EVs) are at the forefront of these investigations. In this study, the therapeutic efficacy of hypoxia hMSCs and the secreted EVs labelled with iron oxides was evaluated in a preclinical model of ischemic stroke. Transcriptome and proteomics analysis of hMSCs under hypoxia indicated alterations in metabolic pathways and EV biogenesis. Hypoxia preconditioning increased EV yield by 57% with similar EV size and exosomal marker expression. EV cargo analysis using proteomics and microRNA‐sequencing revealed that hypoxia preconditioning upregulated expression of metabolic proteins related to hypoxia‐inducible factor signalling, neurogenesis and EV biogenesis. Magnetic resonance imaging following in vivo administration of iron oxide‐labelled hMSCs and EVs provided assessment of biodistribution and therapeutic efficacy. The results indicated differential recovery in sodium levels in rats following hMSC and EV administration compared to the vehicle‐only group, supported by lactate levels and functional assessment. hMSC‐EVs localized to the ischemic lesion and evoked a therapeutic response after a single bolus injection. This study has significance in developing human stem cell‐free therapeutics for treating ischemic stroke.