Kelly B. Walters, a third-year undergraduate student in chemistry, co-authored a paper recently published online by the American Journal of Physiology - Renal Physiology.

Walters was a co-first author of the paper titled “Early lipid changes in acute kidney injury using SWATH lipidomics coupled with MALDI tissue imaging,” which was published on Feb. 24.

For the study, researchers looked for lipids that might be identified as potential biomarkers for detecting acute kidney injury (AKI) earlier than any other current method.

Walters says of the study:

AKI is a real problem because it is the leading cause of hospital morbidity and mortality in critically ill patients. Obviously the earlier you can detect damage, the earlier you can intercede, and hopefully patient outcomes improve this way.

We used SWATH MS (sequential window acquisition of all theoretical mass spectra) and MALDI-IMS (matrix-assisted laser desorption-ionization imaging mass spec) to identify and locate lipids in mouse kidneys that we injured to mimic AKI. We wanted to find at least one lipid that both correlated with the extent of injury and was detectable at an early time point, independent of lipid oxidation. Two ether-linked lipids (plasmalogens in this case) fit our criteria. To further investigate this, we imaged the kidney tissues and found that one of the plasmalogens is localized to the proximal tubules in the kidney, which is the hypothesized site of injury under hypoxic conditions. We performed tissue staining to highlight the tubules and show that they are indeed the structures we located the lipid in, and to also rule out that the lipid increase was not simply from blood flow. We were unable to detect the other plasmalogen, but not everything is detectable with the MALDI-IMS.

Ultimately we found success by identifying and localizing these lipids, which are correlated to kidney injury, and that's a big first step in their potential usage clinically. Future studies will be focused on validating these lipids as biomarkers for really early time points without a biopsy.

Walters’ mentor, Department of Microbiology Associate Professor Dr. Janusz H. Kabarowski, Department of Chemistry Professor Dr. David Graves and Dr. Anupam Agarwal, Program Director of the O’Brien Core Center for Acute Kidney Injury Research, are also co-authors of the paper. Other researchers involved in the study are in UAB’s Division of Pediatric Critical Care, Department of Microbiology, Department of Pharmacology and Toxicology, Targeted Metabolomics and Proteomics Laboratory, Division of Nephrology and the Nephrology Research and Training Center.