Element analysis applied to investigate acute kidney injury induced by red yeast rice supplement

Silica nanoparticles are used in functional foods and tablets to increase drug stability and delivery. We investigated a patient with acute kidney injury with Fanconi syndrome after taking functional food tablets made from red yeast rice using low-vacuum scanning electron microscopy (LVSEM) with an element analysis system. Kidney biopsy revealed proximal tubular necrosis and vacuolization with 10-20 nm black granules, which were similar to the silica nanoparticles found in the functional food tablets and urinary samples, as determined via LVSEM with element analysis. Reabsorbed silica nanoparticles induce oxidative stress in the kidney. Element analysis by LVSEM is useful to investigate a possible cause of acute tubular necrosis in patients with Fanconi syndrome.