Contributions of nuclear magnetic resonance to study of acute renal failure

Nuclear magnetic resonance (NMR) has contributed considerably to our understanding of experimental acute renal failure. Changes in energy metabolism which are caused by ischemia, urinary obstruction, and nephrotoxic drugs have been characterized with NMR spectroscopy. Data from our laboratory and others utilizing 31P NMR have demonstrated that levels of adenosine triphosphate fall rapidly with ischemia, and that the ability of the kidney to regenerate ATP correlates with ultimate functional recovery. Additionally, development of intracellular acidosis appears to occur early with ischemia and may, if severe enough, predict poor functional recovery. Urinary obstruction is associated with the rapid development of a large peak resonating in the phosphodiester region of the P-31 NMR kidney spectrum which is attributable to increases in urinary inorganic phosphate. Nephrotoxic acute renal failure with a variety of nephrotoxins is associated with little to no changes in high energy phosphates. Renal transplant allograft rejection is associated with energy metabolic changes similar to those seen with ischemia; however, the intracellular pH remains normal. These findings allow causes of experimental acute renal failure to be differentiated among each other in both native and transplanted kidneys. With recent advances in NMR software and hardware, the application of this methodology to human acute renal failure is now possible.