Abstract

Chronic Chlamydia pneumoniae infections have been associated with cardiovascular diseases (CVD), but the treatment is difficult. Some drugs used for CVD have been found to have an inhibitory effect on the C. trachomatis infection, which is not considered to be associated with CVD. The purpose of this study was to investigate the effects of heparan sulfate-like glycosaminoglycans, COX inhibitors and rapamycin on the C. pneumoniae infection with cell culture methods.

Almost any conceivable factors may affect the results of cell cultures. This study showed the complex interaction between temperature, time and medium during the pre-treatment before inoculation. The influences of these factors on the results overlapped and interlaced. The simple washing procedure could enhance the infectivity of C. pneumoniae although it is generally considered to cause the loss of chlamydial EBs and sequentially decrease the chlamydial infectivity.

Although the detailed mechanisms were not studied, the results of this study showed that selective COX inhibitors and rapamycin can inhibit the infectivity of C. pneumoniae by inhibiting the growth and maturation, whereas heparan sulfate-like glycosaminoglycans perhaps inhibit the attachment of C. pneumoniae EBs onto the host cells. Recovery and repassage results showed that the growth can be only delayed by selective COX inhibitors, and it can recover to normal level once the drugs were removed. However, rapamycin inhibited the maturation of chlamydial EBs and therefore the infectivity fell down further even when the rapamycin was removed. This study also presented the variations of pathogenicity between different C. pneumoniae strains in vitro. This study is based on in vitro experiments with an acute infection model. Thus, any definite conclusions on the possible antichlamydial effects of the drugs tested in the treatment of cardiovascular diseases which are associated with chronic C. pneumoniae infections cannot be drawn on the basis of this study.