PENK and acute kidney injury: In a recent analysis of the 154 patients with AKI-CS, from the prospective CardShock study, high baseline levels of markers of AKI, such as plasma proenkephalin (P-PENK) > 105.7 pmol/L and neutrophil gelatinase-associated lipocalin (P-NGAL) > 151 ng/mL, at 24 h, were found to be independent predictors of 90-day mortality.