Investigations Into the Mechanisms for Bioenergetic Failure in Sepsis-associated Acute Kidney Injury

Acute kidney injury (AKI) in patients with sepsis has a very poor prognosis with up to 60% mortality. The pathobiology remains to be fully understood. Creatine and phosphocreatine, products of arginine metabolism through L-arginine:glycine amidinotransferase (AGAT) and its sister enzyme guanidinoacetate N-methyl-transferase (GAMT), provide an energy-buffering system that is essential for intracellular adenosine triphosphate (ATP) supply. We hypothesized that sepsis associated AKI may be caused by failure of this energy-buffering system. In series of pilot studies, we explored metabolic and bioenergetic patterns in patients and animals with high risk of developing AKI. These data suggest that sepsis associated AKI may be caused by failure of this alternative renal energy source. In the current application we propose a clinical investigation of renal metabolism and renal bioenergetics in patients with high and low risk of developing sepsis associated AKI. The primary objective is to directly investigate renal AGAT activity through the arginyl metabolites homoarginine, guanidino acetate, and creatine. Secondary objectives are to study renal and systemic hemodynamics, renal oxygenation, glomerular filtration rate (GFR), renal tubular function, and mitochondrial respiration.