Oxidative Stress Induced by Cortisol in Human Platelets.

Area of Science:

• Biochemistry
• Hematology
• Molecular Biology

Background:

• Hypercortisolism impacts platelet function, but exogenous cortisol effects are poorly understood.
• Existing research on cortisol's influence on human platelets yields conflicting results.

Purpose of the Study:

• To investigate the impact of exogenous cortisol on oxidative stress markers in human platelets.
• To elucidate the enzymatic pathways and ROS sources involved in cortisol-induced platelet oxidative stress.

Main Methods:

• Analysis of reactive oxygen species (ROS) production, superoxide anion formation, and lipid peroxidation.
• Measurement of glutathione (GSH) and membrane thiol (SH-group) content.
• Assessment of enzyme involvement (src, syk, PI3K, AKT) and inhibition studies using specific pathway modulators (e.g., NADPH oxidase inhibitors, mitochondrial respiratory chain inhibitors).

Main Results:

• Cortisol significantly elevated ROS production, superoxide anion formation, and lipid peroxidation in platelets.
• Cortisol decreased platelet GSH and membrane SH-group content, indicating depletion of antioxidant defenses.
• Involvement of src, syk, PI3K, and AKT enzymes was demonstrated; NADPH oxidase 1 activity and uncoupled oxidative phosphorylation were identified as key ROS sources.

Conclusions:

• Exogenous cortisol potentiates oxidative stress in human platelets by enhancing ROS generation and impairing antioxidant capacity.
• Cortisol-induced platelet oxidative stress involves NADPH oxidase 1 and mitochondrial complex I/III, but not complex II/IV.
• This cortisol-mediated platelet oxidative stress may contribute to arterial and venous thrombosis, increasing cardiovascular disease risk.