ヒト血管病変と感染

―感染寄生体は病原因子となりうるか?―

抄録

Virus infection as a pathogen in human vascular diseases has been an important and unsolved issue to be studied. According to Koch's postulates, several conditions should be met to define an organism as a pathogen of human disease: especially, 1) to confirm the whole or a part of structure of microorganism including genomic DNA or RNA in the human material, 2) whether infection of microorganism can induce similar disease in mammals. Several bacterias such as Chlamydia pneumoniae or Hericobactor pylori have been studied according to these postulates, however, it has been hazardous for virus research to establish animal model due to species-specificity or tropism. Human cytomegalovirus (HCMV) is one of these candidates, and HCMV DNA has been frequently detected in the both normal and disordered aorta, however, it is sure that presence of viral genome does not always imply its pathogenecity. As important evidences indicating the pathogenesity of HCMV in human vascular diseases, our recent studies demonstrated virus-specific gene transcription in the surgical specimens of “inflammatory” aortic aneurysms but not in any other human aortic tissue, and also exhibited that the immediate early (IE) gene product stimulates vascular smooth muscle proliferation in rabbit carotid arteries. Whereas these findings suggest the pathogenic ability of HCMV in human vascular tree, some issues to be sollved including the reason why HCMV-IE does not induce any inflammatory response in rabbit. Clearly the immune system is varied among the species and this point should be studied very carefully. Overall, although it seems nearly slow, we consider that the studies for virus etiology in human vascular disorders are now getting progression.