Renal Injury and Renalase as a Biomarker

Kidneys are the most frequently injured organ in the genitourinary system, but there is no specific biological marker for this trauma. In a study, researchers have suggested that renalase levels might be a useful biomarker for the diagnosis of renal injury due to blunt renal trauma. The study findings were published in the Journal of Pediatric Urology on September 16, 2021.

Renalase, identified as a new monoamine oxidase enzyme, is mainly expressed in the kidney and also found in the heart, small intestine, brain, and skeletal muscle. It has the function of metabolizing catecholamines and their substrates. Renalase may be a descriptive biomarker of the pathology that causes renal ischemia, nephrotoxicity, and acute renal failure. To further explore, Dr. Mehmet Saraç and his team conducted a study to investigate the role of serum and urine levels of renalase for the diagnosis of renal injury in rats with experimentally induced blunt renal trauma.

Study Design

In this preclinical study, the researchers included 33-month-old Sprague–Dawley adult male rats and divided them into five groups (n = 6) as follows:

• Control (group 1)
• Sham (Placebo- group 2)
• Right nephrectomy (group 3)
• Left renal trauma (group 4)
• Right nephrectomy plus left renal trauma (Group 5)

They acquired serum samples at 3, 24, and 48 hours post-trauma and urine samples between 0–24 and 24–48 hours post-trauma. They further assessed the changes in serum and urine levels of renalase, dopamine, epinephrine, metanephrine, normetanephrine, urea, and creatinine after blunt renal trauma.

Key Findings of the Study

Upon analysis, the researchers observed no significant changes in serum levels of these compounds were observed at 3 hours post-trauma in Groups 1 and 2 or urine collected sequentially at 0–24 and 24–48 hours.

However, they noted that the levels of renalase, dopamine, metanephrine, and normetanephrine in serum increased during hour 3 in Groups 4 and 5.

Also, they observed an increase in urine levels of renalase, dopamine, epinephrine, metanephrine, and normetanephrine at hours 0–24 in Groups 4 and 5.

The authors concluded, "A definitive diagnosis of traumatic renal injury in children is made with contrast-enhanced computed tomography. However, the scan results in high doses of radiation exposure to children. Here, we report for the first time that renalase levels may be useful as a biomarker for the diagnosis of renal injury due to blunt renal trauma."

For Further Information

DOI: https://doi.org/10.1016/j.jpurol.2021.09.013