Mesenchymal stem cells-derived therapies for subarachnoid hemorrhage in preclinical rodent models: a meta-analysis

Mesenchymal stem cells (MSCs) and MSCs-derived extracellular vesicles (EVs) have emerged as potential novel therapies for subarachnoid hemorrhage (SAH). However, their effects remain incompletely understood. We aim to comprehensively evaluate the effect of MSCs-derived therapies in rodent models of SAH.

We searched PubMed, EMBASE, and Web of Science up to September 2021 to identify studies that reported the effects of MSCs or MSCs-derived EVs in a rodent SAH model. Neurobehavioral score was extracted as the functional outcome, and brain water content was measured as the histopathological outcome. A random-effects model was used to calculate the standardized mean difference (SMD) and confidence interval (CI).

Nine studies published from 2018 to 2021 met the inclusion criteria. Studies quality scores ranged from 5 to 10, with a mean value of 7.22. Our results revealed an overall positive effect of MSCs and MSCs-derived EVs on the neurobehavioral score with a SMD of - 2.21 (95% CI - 3.14, - 1.08; p < 0.0001). Meanwhile, we also found that MSCs and MSCs-derived EVs reduced brain water content by a SMD of - 2.09 (95% CI - 2.99, - 1.19; p < 0.00001). Significant heterogeneity among studies was observed, further stratified and sensitivity analyses did not identify the source of heterogeneity.

Our results suggested that MSCs-derived therapies prominently improved functional recovery and reduced brain edema in the rodent models of SAH. Notably, the limitations of small sample size should be considered when interpreting the results, and large animal studies and human trials are needed for further investigation.