Efficacy of Irisin on neurological and tissue-related outcomes in ischemic brain injuries; a scoping review

Evidence indicates the protective role of Irisin on nervous tissue following ischemic events, bypreventing the cascades of secondary damage. We conducted this scoping review to summarize what has beendiscovered so far on the neuroprotective effects of Irisin, with a focus on ischemic stroke.

Searchstrategies were designed based on the keywords related to ischemic stroke and Irisin. Next, an extensive searchin Medline, Embase, Scopus, and Web of Science was conducted by the end of April 2022. Two researchers inde-pendently reviewed the articles and performed the screening of the selected papers according to the inclusioncriteria. Finally, the required data were extracted to a checklist designed based on the PRISMA guideline. The“meta” package was used for the meta-analysis, and heterogeneity between studies was assessed using the I2test.

Pooled data analysis showed that the Irisin administration significantly improved the neurologicalfunction following cerebral ischemia / reperfusion injuries (SMD = 3.08; 95% CI: 1.10, 5.06; p<0.0001). Addi-tionally, meta-regression demonstrated that the improvement in neurological function was directly related tothe dose of administered Irisin (meta-regression coefficient = 0.03; p = 0.02). Moreover, Irisin administrationsignificantly reduced the volume of infarcted lesions (SMD= -3.14; 95% CI: -4.23, -2.04; p<0.0001), the amountof edema in the brain (SMD= -2.30; 95% CI: -4.07, -0.53; p<0.0001), and the extend of neuronal-cell apoptosisrate (SMD= -4.67; 95% CI: -8.15, -1.19; p<0.0001).

The present study demonstrates that the admin-istration of Irisin in animal models of cerebral ischemia / reperfusion injuries is associated with a significantdose-dependent improvement in neurological function. Due to the limited number of articles, more researchon the aim of finding the optimum Irisin dosage is in high demand.