Urine Markers Associated with Acute Kidney Injury

A protein and its RNA found in urine appear to be associated with acute kidney injury (AKI).

Physical symptoms are not typically present with AKI as they are with brain or heart injuries. Therefore, scientists have been looking for markers of AKI, with the hope that early detection will lead to early therapy to prevent kidney failure.

Richard Zager, M.D. at the Clinical Research Division, Fred Hutchinson Cancer Research Center (Seattle, WA, USA) and colleagues investigated whether certain molecules that are produced during injury and infection might be excreted in the urine and serve as diagnostic markers.

The investigators examined the diagnostic potential of monocyte chemoattractant protein-1 (MCP-1), a protein that plays a role in recruiting immune cells to injured or infected sites in the body. This protein has been found in the joints of people with rheumatoid arthritis and in the urine of people with lupus.

Elevated levels of MCP-1 as well as its mRNA (the template for protein synthesis) were detected in urine samples from both mice and human patients with AKI. This suggests that the gene that encodes this mRNA and protein is activated in patients with AKI.

Using a chromatin immunoprecipitation assay, the investigators also showed changes in certain proteins (histones) that can activate the gene that produces MCP-1. This is the first time that the ability to detect these protein modifiers have been identified in human urine samples.

"This is a new diagnostic test that provides information about what processes are actually inducing acute kidney injury; however, a much larger prospective study is required to ultimately determine clinical utility," said Dr. Zager.

Related Links:
Clinical Research Division, Fred Hutchinson Cancer Research Center