Researchers from Berlin and Würzburg announced on July 11 that oxalic acid, known for its role in kidney stone formation, may also drive systemic inflammation and heart damage in individuals with impaired kidney function. The findings were published in "Cardiovascular Research."
Chronic kidney disease patients face a significantly higher risk of cardiovascular death and persistent inflammation, the causes of which remain only partly understood. Oxalic acid is a natural metabolic by-product found in certain foods and typically excreted by healthy kidneys. When kidney function declines, oxalate accumulates, potentially promoting inflammatory processes.
The Experimental Biomedicine II department at Würzburg University Hospital collaborated with the Experimental and Clinical Research Center (ECRC), jointly operated by Charité – Universitätsmedizin Berlin and the Max Delbrück Center, to study how oxalate-induced kidney damage relates to systemic inflammation and cardiovascular injury. "In our research project, an oxalate-enriched diet activated the immune system systemically in mice. In other words, inflammatory processes spread throughout the body. This led not only to kidney damage, but also to pathological changes in the heart that reduced cardiac function," said Dr. Hendrik Bartolomaeus of Würzburg University Hospital.
The team identified interleukin-17A (IL-17A) as a key cytokine involved; IL-17A is produced by specific immune cells that amplify inflammation. Researchers observed increased IL-17A production due to oxalate exposure and detected elevated IL-17A levels in patients with primary hyperoxaluria—a rare disorder where excess liver-produced oxalate accumulates due to enzyme defects.
Dr. Nicola Wilck of ECRC said, "In the animal model, several signs of disease improved simultaneously... The mice's kidneys functioned better, inflammation and fibrosis declined, and heart damage was reduced." The researchers described this as a therapeutically targetable axis: oxalate–IL-17A–cardiorenal injury.
Looking ahead, co-authors Professor Felix Knauf’s teams at Charité – Universitätsmedizin Berlin and Mayo Clinic have already shown that high blood oxalate levels are common among people with impaired renal function—and are associated with increased cardiovascular risk. Researchers plan further studies on larger patient cohorts to determine whether these inflammatory mechanisms appear broadly among chronic kidney disease patients.
