Tissue pH changes in renal preservation

Abstract

Ischaemic tissue rapidly becomes acidotic and it has been shown that a fall in pH has a deleterious effect on a number of tissues, including decreased oxygen consumption in diaphragm¹ and loss of contractility² in association with the depression of several metabolic processes³ in myocardium. A number of studies have sought to correlate tissue pH during ischaemia with renal viability. Surface pH is easily measured but has not been found to be consistently helpful^4,5. The pH on the surface may not be an accurate reflection of changes within tissue or cells. Other workers have approached the problem by attempting to modify renal viability by using buffered flush solutions, but in the absence of measurements of pH a cause-and-effect relationship cannot be substantiated^6,7. A major obstacle in this field is the difficulty in measuring intracellular pH, particularly under conditions of ischaemia^8,9. Nuclear magnetic resonance (NMR) spectroscopy using the ³¹P nucleus has been shown to be a reliable means of measuring pH even during ischaemia^10–13 since it is able to determine the degree of protonation of inorganic phosphate¹⁴. We have measured pH by ³¹P NMR in three series of experiments.