Do ochratoxin A and citrinin injure renal cells through oxidative stress and mitochondrial dysfunction?

Ochratoxin A (OTA) and citrinin (CIT) are co-occurring mycotoxins with convergent nephrotoxic mechanisms in experimental models. The overall claim is supported, with the important qualification that mixture effects are context-dependent rather than uniformly synergistic.

Renal-cell toxicity and mechanisms

• OTA: In human HK-2 proximal-tubule cells, OTA increased reactive oxygen species (ROS); N-acetylcysteine reduced ROS and JNK-associated apoptosis. In primary human proximal-tubule cells, OTA increased superoxide and impaired mitochondrial respiration and ATP production, alongside altered mitochondrial morphology.
• CIT: Kidney-cell and mouse studies show increased ROS and lipid peroxidation with depletion of glutathione, superoxide dismutase, and catalase. CIT also caused mitochondrial structural injury, mitochondrial ROS, DRP1 upregulation, and cytochrome-c release. DRP1 inhibition and mitochondria-targeted interventions reduced cell death.
• These results support an interconnected pathway in which oxidative stress and mitochondrial injury contribute to tubular-cell death. CIT has additionally been associated with pyroptosis, apoptosis, and necroptosis (“PANoptosis”) in kidney-cell and mouse models.

Combined exposure

• In HK-2 cells, nanomolar OTA–CIT co-exposure induced inflammatory and epithelial-to-mesenchymal/fibrotic markers when neither toxin alone did. Vero kidney-cell studies also reported synergistic oxidative damage and reduced viability.
• However, interactions vary by dose and endpoint: experiments have also found additive, null, or antagonistic effects. In rats, co-administration increased renal CIT concentrations about 3- to 6-fold, plausibly through competition for renal organic-anion transporters, while renal OTA could decrease.

Bottom line

• OTA and CIT can each injure renal experimental models through oxidative and mitochondrial mechanisms, and their combination can amplify toxicity under defined conditions. This is mechanistically credible but derives mainly from cell and animal studies; it does not establish a predictable synergistic renal risk at typical human dietary exposures.