Does citrinin increase oxidative stress and mitochondrial injury in the kidney?

Citrinin is a potent mycotoxin that selectively targets the kidney, accumulating in renal proximal tubule cells and causing cellular degeneration, necrosis, and significant renal dysfunction.

Mechanisms of cellular and mitochondrial injury

• Transporter-mediated entry: Citrinin actively enters renal proximal tubule cells via basolateral organic anion transporters OAT1 and OAT3, establishing high intracellular concentrations.
• Oxidative stress cascade: This intracellular accumulation triggers robust reactive oxygen species (ROS) generation and lipid peroxidation, marked by elevated malondialdehyde (MDA) levels and the rapid depletion of essential antioxidants, including glutathione (GSH), superoxide dismutase (SOD), and catalase.
• Mitochondrial damage and apoptosis: Citrinin directly impairs mitochondrial oxidative phosphorylation by disrupting complex I and ATP synthase. This dissipates mitochondrial membrane potential and halts ATP synthesis, triggering cytochrome c release and activating the caspase-9/caspase-3 cascade to drive proximal tubule cell apoptosis.

Impact on renal detoxification workload

• Active transport burden: Because citrinin has low permeability, its clearance relies on active tubular secretion rather than passive filtration—with approximately 75% of the dose recovered in urine in animal models. This pathway increases the transport burden and alters rOat1 and rOat3 transporter expression.
• Metabolic exhaustion: Active renal clearance is highly energy-dependent. By damaging mitochondria and depleting ATP and GSH reserves, citrinin deprives proximal tubule cells of the metabolic energy required to sustain active transport, transforming normal excretion into an overwhelming cellular stressor that impairs overall tubular function.

Bottom line

• Citrinin acts as a direct nephrotoxin by exploiting OAT1/OAT3 pathways to accumulate in the kidney, where it initiates a destructive cycle of oxidative stress, mitochondrial failure, and ATP depletion that severely compromises the organ's detoxification capacity.