Objective: We investigated whether Chlamydia pneumoniae (CP) and Mycoplasma pneumoniae (MP) are present in aortic valve stenosis (AS).
Methods: Immunohistochemistry was utilized to identify CP antigens, in situ hybridization to identify MP DNA, and electron microscopy was used to evaluate the following three groups: Normal - 11 normal autopsy valves; Atherosclerosis - 10 autopsy valves from patients with systemic atherosclerosis and no AS; and AS - 14 surgical specimens of AS analyzed in 3 sub-regions: AS-Preserved - peripheral, preserved regions; AS-Fibrosis - peri-calcified fibrotic tissue; and AS-Calcification - calcified nodules.
Results: The positive area fraction of CP antigen median values were 0.09, 0.30, 0.18, 1.33, and 3.3 in groups Normal, Atherosclerosis, AS-Preserved, AS-Fibrosis, and AS-Calcification, respectively. CP density was significantly greater in Atherosclerosis and AS-Calcification than in Normal (P<0.05). Within the AS group, the amount of CP was greater in the Calcification and Fibrosis regions (P<0.05). MP-DNA positive area fraction (median values) were 0.12, 0.44, 0.07, 0.36, and 1.52 in groups Normal, Atherosclerosis, AS-Preserved, AS-Fibrosis, and AS-Calcification, respectively. The amount of MP-DNA was greater in AS-Calcification than in Normal (P<0.05). Within the AS group, MP-DNA was in larger quantity in the Calcification and Fibrosis regions (P<0.05).
Conclusion: AS Calcified nodes present higher concentration of CP and MP suggesting that these bacteria may be associated with the development of calcification and inflammation. This adds novel similarities between AS and the atherosclerosis process, which may have infection mechanisms involved.