In vitro degradation of aortic elastin by Chlamydia pneumoniae

Objectives: to investigate whether Chlamydia pneumoniae (C. pneumoniae) may increase elastin degradation in the aortic wall. Materials and Methods: eighteen full thickness aortic wall samples from non -aneurysmal infrarenal abdominal aortas were collected from autopsies. Two adjacent and equally large pieces were cut out of each aortic sample. From each sample, one piece was incubated in a HEp-2 cell culture infected with C. pneumoniae and the other piece was incubated in all uninfected HEp-2 cel l culture. The incubation time was one week at 35 degreesC. The concentrati on of elastin-derived peptides (EDP) (ng/ml) in the medium of each cell cul ture was measured in duplicate. For each paired sample, delta-EDP (EDP in H Ep-2 cell culture infected with C. pneumoniae - EDP in uninfected HEp-2 cel l culture) was calculated. Result: there was a significantly increased degradation of aortic elastin, estimated by EDP concentrations in cell culture conditioned medium, when ao rtic wall samples were incubated in C. pneumoniae cultures compared with un infected cultures (p=0.025, Wilcoxon signed ranks test). Conclusion. these results indicate that there is a relationship between the presence of C. pneumoniae and increased elastin degradation in the aortic wall in vitro. This suggests C. pneumoniae in the aortic wall directly or i ndirectly leads to the degradation of aortic elastin.