Vaccine-induced inflammation attenuates the vascular responses to mental stress

• Typhoid vaccination induced increases in inflammation in a healthy population.
• Elevated inflammation did not alter the cardiac responses to mental stress.
• However, inflammation attenuated the vascular responses to a mental stress task.
• This may suggest a mechanism through which stress may trigger myocardial infarction.

Inflammation is associated with poorer vascular function, with evidence to suggest that inflammation can also impair the vascular responses to mental stress. This study examined the effects of vaccine-induced inflammation on vascular responses to mental stress in healthy participants. Eighteen male participants completed two stress sessions: an inflammation condition having received a typhoid vaccination and a control (non-inflamed) condition. Tumor necrosis factor-alpha and interleukin-6 (p's < .001) increased following vaccination, confirming modest increases in inflammation. Mental stress increased blood flow, blood pressure, heart rate, and cardiac output in both conditions (all p's < .001), but the blood flow response to stress was attenuated having received the vaccination compared to the control condition (p's < .05). These results further implicate the interaction between inflammation and the vasculature as a mechanism through which stress may trigger myocardial infarction.