MMP9 and epilepsy: Studies on animals were supplemented with clinical data demonstrating that in human patients with different types of epilepsy, occurrence of chronic seizures is correlated with the elevated levels of MMP-9 in serum, plasma, and cerebrospinal fluid as well as in the brain (Leppert et al., 2000; Suenaga et al., 2008; Li et al., 2012; Romi et al., 2012; Konopka et al., 2013; Zybura-Broda et al., 2016).