Urinary gamma-glutamyl transpeptidase, an indicator of renal ischaemic injury and homograft rejection

Area of Science:

• Nephrology
• Biochemistry
• Transplantation Medicine

Background:

• Gammaglutamyl transpeptidase (GGT) is concentrated in renal proximal tubules, vulnerable to ischemic damage.
• GGT's localization and assay simplicity suggest its utility in assessing renal ischemia.
• Assessing GGT activity offers a potential method for quantifying renal ischemic injury.

Purpose of the Study:

• To evaluate urinary GGT as a biomarker for renal ischemic injury.
• To correlate urinary GGT levels with transplant rejection in human kidney recipients.

Main Methods:

• Canine model of unilateral renal ischemia (90 min and 5 min durations).
• Measurement of urinary GGT activity in experimental animals.
• Daily 24-hour urinary GGT estimations in 20 human kidney transplant patients.

Main Results:

• Canine urinary GGT increased up to 70-fold after 90 min of renal ischemia.
• Significant GGT elevation was observed after only 5 min of ischemia in dogs.
• A strong correlation was found between elevated urinary GGT and clinical diagnosis of transplant rejection in humans.

Conclusions:

• Urinary GGT is a sensitive indicator of acute renal ischemic injury.
• Urinary GGT monitoring can aid in the early diagnosis of kidney transplant rejection.