Exosome therapies improve outcome in rodents with ischemic stroke; meta-analysis.

OBJECTIVE: Exosome therapy has been theorized to be safer, more effective, and less cumbersome in replacing stem cell therapies for tissue repair and regeneration. There remains considerable uncertainty on whether exosome therapy is efficacious and safe for recovery from brain injury due to cerebral infarction. There is growing consensus that systematic reviews of data, from preclinical studies which yielded conflicting and confusing results, can provide valuable directions for novel therapeutic options for several clinical conditions. This study systematically evaluated the efficacy of exosome therapy in ischemic stroke in preclinical studies in rodent models.

METHODS: We reviewed existing literature on exosome therapy in rodent stroke models from various databases, and reviewed the interventional measures, and outcome measures systematically, with changes in the infarct volume and functional scores as outcome parameters. Seventeen homogeneous studies were found qualitatively acceptable for meta-analysis. The study used software RevMan 5.3 to conduct the meta-analysis (PROSPERO Register Number: CRD42022314138) RESULTS: Compared to placebo, exosomes treated ischemic stroke models showed significantly reduced brain infarct volume and improved functional recovery on days 7 and 28. Though there are no safety concerns reported in any preclinical studies, there is insufficient data to make robust conclusions on the therapy's safety.

INTERPRETATION: Therapy with subcellular exosomes is a promising treatment to be explored further in animal ischemic stroke models to arrive at robust conclusions for its safety and therapeutic dosage. This must precede Phase I and II- human randomized clinical trials to establish the safety and proof of concept of efficacy of exosome therapy in human ischemic stroke.