Exploration of zileuton protective mechanisms against vancomycin-associated nephrotoxicity

Vancomycin is one of the most commonly used parenteral antibiotics for treating drug-resistant bacterial infections, however, it is hindered by nephrotoxicity. We previously demonstrated that zileuton could delay the onset of vancomycin-associated nephrotoxicity in rats. Here, we sought to understand the mechanism(s) of zileuton renal protection. Sprague-Dawley rats were administered vancomycin (200 mg/kg) and zileuton (1 and 4 mg/kg) daily for 10 days. After 3 days, kidneys were collected from select animals for histopathological analysis of renal injury. Single-dose vancomycin serum pharmacokinetics and renal tissue spatial distribution with adjuvant zileuton were evaluated. In vitro, proximal tubular cells were exposed to vancomycin and zileuton; cell viability, vancomycin accumulation, ROS levels, and p62/KEAP1 and ferroptosis-related protein levels were measured. Vancomycin was associated with increased serum creatinine and proximal tubule injury in rats including tubular cell necrosis, cytoplasmic vacuolization, interstitial edema, and mononuclear inflammatory cell infiltration. Adjuvant zileuton reduced renal injury and serum creatinine elevation without altering vancomycin serum pharmacokinetics or renal tissue distribution. In vitro, vancomycin exposure resulted in cellular injury, increased ROS, and significantly decreased HO-1 levels. Concomitant zileuton reduced cellular injury, decreased ROS, and rescued HO-1 levels. These preliminary findings indicate that zileuton may be protective against vancomycin-associated renal injury potentially by rescuing HO-1 levels and reducing oxidative stress in proximal tubular cells. Attenuation of nephrotoxicity would allow the optimal clinical use of vancomycin to treat drug-resistant bacterial infections, which could reduce patient harm and hospitalization costs.