KLK1 and acute kidney injury: In both AKI and controls, KLK1 specific methylation in urine DNA was significantly lower than global LINE-1 methylation in urine DNA (AKI 40.95 ± 7.06 vs. 69.53 ± 1.54%; p = 0.003; controls 30.35 ± 5.88 vs. 69.29 ± 1.05%; p < 0.0001) (Figure 4).