Acute Chlamydia pneumoniae infection causes coronary endothelial dysfunction in pigs

Area of Science:

• Cardiovascular Research
• Infectious Diseases
• Endothelial Function

Background:

• Coronary endothelial dysfunction is a key factor in acute coronary syndromes (ACS).
• Acute Chlamydia pneumoniae infection is epidemiologically linked to ACS.
• The direct impact of acute C. pneumoniae infection on coronary vasomotor function remains unclear.

Purpose of the Study:

• To investigate the effect of acute Chlamydia pneumoniae infection on the endothelial vasomotor function of porcine coronary vessels.
• To assess changes in coronary microcirculation and epicardial vessel reactivity following C. pneumoniae inoculation.

Main Methods:

• Pigs were intratracheally inoculated with C. pneumoniae or saline.
• Endothelium-dependent reactivity was assessed using coronary flow velocity (CFV) in response to bradykinin.
• Reactivity was measured before and after administration of glutathione and L-arginine.
• Coronary ring relaxation studies and biochemical analyses (nitrate-nitrite, fibrinogen, NOS activity) were performed.

Main Results:

• Infected pigs showed significantly decreased CFV after bradykinin at 3 days and 2 weeks post-inoculation.
• Glutathione and L-arginine improved CFV in infected animals at 2 weeks.
• Bradykinin-induced relaxation of coronary rings was impaired in infected animals.
• Plasma nitrate-nitrite, fibrinogen, and coronary nitric oxide synthase (NOS) activity were elevated in infected pigs.

Conclusions:

• Acute C. pneumoniae infection induces endothelial dysfunction in both resistance and epicardial coronary vessels.
• The infection promotes a pro-coagulant status.
• These findings provide a potential mechanism for the association between acute infection and ACS.