Major depression induces oxidative stress and platelet hyperaggregability.

Area of Science:

• Biochemistry
• Hematology
• Neuroscience

Background:

• Previous studies showed impaired L-arginine-nitric oxide-cGMP pathway in major depression (MD) linked to platelet dysfunction.
• The arginase pathway and phosphodiesterase 5 (PDE5) roles in MD-associated platelet alterations require further investigation.

Purpose of the Study:

• To evaluate the arginase pathway, PDE5 expression, oxidative status, and platelet aggregation in untreated MD patients.
• To elucidate the impact of these factors on platelet function and thrombotic risk in MD.

Main Methods:

• Blood samples from 22 treatment-naive MD patients and 27 healthy controls were analyzed.
• Platelet arginase II activation, PDE5 expression, oxidative stress markers (protein carbonylation, NADPH oxidase), and platelet aggregation were assessed.

Main Results:

• MD patients exhibited increased platelet arginase II activation, competing with L-arginine for nitric oxide (NO) production.
• Overexpression of NADPH oxidase and PDE5, along with increased protein carbonylation, was observed in MD platelets.
• Platelet hyperaggregability was significantly higher in MD patients compared to controls.

Conclusions:

• Increased intraplatelet arginase activation, PDE5 overexpression, and oxidative stress contribute to L-arginine-NO-cGMP pathway dysfunction in MD.
• These alterations in platelet function may increase thrombotic risk in individuals with major depression.