FSTL1 and brain ischemia: The role and mechanism of circHECTD1 in OGD/R-induced cell damage have been investigated by detecting levels of CircHECTD1, miR-27a-3p, and Follistatin-like 1 (FSTL1) by quantitative real-time polymerase chain reaction (RT-qPCR) in a model of brain ischemia [42].