| Research Abstract |
AM is widely distributed in human tissues, especially in cardiovascular and endocrine tissues. In the vessels, AM is immunohistochemically present in the vascular smooth muscle cells (SMCs) and endothelial cells (Ecs). In the atherosclerotic lesions, the peptide is present not only in these cells, but also in macrophages, and the most intense AM immunoreactivity is detected in macrophages located in the shoulder lesion of atheromatous plaque, considered to be a rupture prone region. AM inhibits tissue factor production, and AM augments production and release of tissue factor pathway inhibitor from aortic ECs. AM also induced release of antithrombin and urokinase-type plasminogen activator from ECs. Taken together, these antithrombotic properties of the peptide would play an important role in the maintenance of blood circulation. Furthermore, AM immunoreactivity is observed in mucosal and glandular epithelia of the gastrointestinal, respiratory and reproductive systems. AM and proadrenomedullin N-terminal 20 peptide (PAMP) showed a strong antibacterial activity against E. coli. In addition, AM is also present in the auditory system.. These lines of evidence suggest that AM and its related peptides not only play a role in vasodilatation, but also exhibit multiple biological activities in mammals.
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