Oxidative stress in critically ill neonatal foals.
Authors: Wong David, Sahoo Dipak Kumar, Faivre Cosette, Kopper Jamie, Dersh Katie, Beachler Theresa, Esser Melissa
Journal: Journal of veterinary internal medicine
Summary
# Oxidative Stress in Critically Ill Neonatal Foals Systemic infection and critical illness trigger excessive production of harmful reactive oxygen species (ROS) in people, yet this mechanism has received minimal investigation in equine neonates despite high mortality rates in hospitalised foals. Wong and colleagues measured blood concentrations of hydrogen peroxide, oxidative damage markers (malondialdehyde and protein carbonyl), and key antioxidant enzymes in 72 hospitalised and 21 healthy neonatal foals at admission, hypothesising that critically ill foals would exhibit elevated ROS and oxidative injury markers alongside depleted antioxidant reserves. Significantly ill foals (n=51) demonstrated markedly elevated hydrogen peroxide (6.8 versus 2.6 nmol/mL), malondialdehyde (114.3 versus 31.2 nmol/mL), and protein carbonyl (0.12 versus 0.07 nmol/mg protein), whilst showing severely compromised antioxidant defences—catalase activity reduced to near-undetectable levels (0.02 versus 0.4 mU/mg protein), glutathione halved (110.7 versus 238.5 µg/mL), and glutathione reductase and peroxidase both substantially diminished. These findings establish oxidative stress as a significant pathological feature of neonatal foal sepsis and critical illness, suggesting that antioxidant supplementation or modulation strategies merit consideration in clinical management protocols alongside conventional antimicrobial and supportive care, though further work is needed to determine whether targeting oxidative stress improves outcomes in this vulnerable population.
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Practical Takeaways
- •Monitor oxidative stress biomarkers (ROS, MDA, protein carbonyl) and antioxidant levels in critically ill foals as potential indicators of disease severity and sepsis
- •Consider antioxidant supplementation or support strategies during treatment of sick neonatal foals, particularly those with confirmed or suspected sepsis and bacteremia
- •Oxidative injury appears to be a significant pathophysiologic mechanism in equine neonatal sepsis, warranting inclusion in comprehensive critical care management protocols
Key Findings
- •Ill foals had significantly higher H2O2 concentrations (6.8 ± 4.6 nmol/mL) compared to healthy foals (2.6 ± 1.4 nmol/mL)
- •Ill foals demonstrated elevated MDA levels (114.3 ± 94.0 nmol/mL) versus healthy foals (31.2 ± 14.4 nmol/mL), indicating lipid peroxidation
- •Ill foals showed significantly reduced antioxidant capacity including catalase (0.02 vs 0.4 mU/mg protein), glutathione (110.7 vs 238.5 μg/mL), and glutathione peroxidase (0.007 vs 0.01 mU/mg protein)
- •Oxidative stress markers and antioxidant depletion may serve as measurable biomarkers for sepsis severity in critically ill neonatal foals