Acute Active, But Not Passive, Psychological Stress Increases Nonclassical Monocyte Proportions

Area of Science:

• Immunology
• Psychoneuroimmunology
• Cardiovascular Disease Research

Background:

• Psychological stress is a modifiable risk factor for cardiovascular disease (CVD).
• Stress-induced inflammation may mediate CVD risk.
• Monocyte subset shifts (classical, intermediate, nonclassical) can signal a pro-inflammatory environment.

Purpose of the Study:

• To investigate the impact of acute active and passive psychological stress on monocyte subsets and leukocyte count ratios.
• To determine if stress alters the balance of monocyte subsets, indicating a pro-inflammatory shift.

Main Methods:

• Twenty-four participants underwent passive (International Affective Picture System) and active (Paced Auditory Serial Addition Test) stress tasks.
• Blood samples were collected at baseline, post-stress, and during recovery.
• Changes in monocyte subsets (CM, IM, NCM), Systemic Inflammation Response Index (SIRI), and neutrophil:lymphocyte ratio (NLR) were analyzed.

Main Results:

• Active stress (PASAT) significantly decreased classical monocyte proportions and increased nonclassical monocyte proportions.
• Passive stress (IAPS) did not induce significant changes in monocyte subsets.
• Neither stressor affected SIRI or NLR compared to baseline.

Conclusions:

• Acute active psychological stress promotes a pro-inflammatory shift in monocyte subsets.
• Passive psychological stress does not appear to alter monocyte subset profiles.
• These monocyte subset changes represent a potential advancement in inflammatory markers for assessing acute psychological stress response.