Proenkephalin A at Initiation and Discontinuation of Kidney Replacement Therapy

Acute kidney injury (AKI) is a common problem encountered in the intensive care unit (ICU), estimated to occur in up to 60% of all critically ill patients, depending on the definition. Recent large randomized clinical trials in critical care nephrology have focused on the optimal timing of initiation of acute kidney replacement therapy (KRT). However, less is known about the ideal circumstances in which KRT may be successfully discontinued. KRT is a complex and expensive therapy, with complications including catheter-associated infections, hemorrhage, hemodynamic instability, and potential delayed renal recovery.

The novel serum-biomarker proenkephalin A 119-159 (penkid) is a stable fragment derived from the precursor enkephalins, which are known as small endogenous opioid peptides and are produced throughout the human body, including the kidneys. Plasma concentrations of penkid have been found to be strongly negatively correlated with measured glomerular filtration rate. Whether penkid may have a role in initiation and discontinuation of KRT remains unknown.