124 Cystatin C may have an important role in brain injuries as its enhanced expression has been observed in response to different types of insults to the brain, such as ischemia and epilepsy. [125] [126] [127] Regarding constant serum concentrations of cystatin C it is a suitable marker for glomerular filtration rate (GFR) and kidney function and thus has a possible application as a replacement for creatinine.