Involvement of TLR2 and TLR4, Chlamydophila pneumoniae and Mycoplasma pneumoniae in adventitial inflammation of aortic atherosclerotic aneurysm


Aortic atherosclerotic aneurysm (AAA) is associated with adventitial inflammation where infection is suggested to have a role. Co-infection with Chlamydophila pneumoniae (Cp) and Mycoplasma pneumoniae (Mp) was linked with coronary plaque rupture, in association with vessel dilatation and adventitial inflammation. Pathogens are recognized by Toll-like receptors (TLRs) development of the inflammatory process. Objective: Here, we studied whether co-infection by Cp and Mp was involved in the increased inflammation present in AAA and if it could be associated with deficient expression of TLRs. We compared human samples of AAA with non-dilated human aortic atherosclerotic lesions, regarding the amount of Cp and Mp antigens, and expression of TLR2 and TLR4. Methods: Two groups of aorta fragments were analyzed: G1 (n = 13) moderate atherosclerosis and G2 (n = 14) AAA samples, through immunohisto-chemistry and in situ hybridization methods. Results: Mp and Cp antigens in intima/medial layer were greater in G2 than G1, with no difference in adventitia. TLR2 and TLR4 were higher in G2 than G1 adventitia fat. There was a correlation between Mp versus TLR2 and of TLR4 in intima/medial layer and in adventitia of G1, but there was a lack of correlation in G2. In Cp adventitia, the correlation in G1 was high with TLR2 but not with TLR4, and in G2 the correlation was positive for both TLRs. Conclusion: This study favors the concept that symbiotic co-infection by Cp and Mp participates in the pathogenesis of AAA. It also emphasizes that adventitial fat is the initial site for colonization of these bacteria that probably reach the tissue through vasa vasorum. An exacerbated immune reaction is not efficient to control the infection that reaches and proliferates in high levels at the medial and intimal layer, contributing to the development of vessel dilatation.

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de Assis, R. , de Lourdes Higuchi, M. , Reis, M. , Palomino, S. , Crespo Hirata, R. and Hirata, M. (2014) Involvement of TLR2 and TLR4, Chlamydophila pneumoniae and Mycoplasma pneumoniae in adventitial inflammation of aortic atherosclerotic aneurysm. World Journal of Cardiovascular Diseases, 4, 14-22. doi: 10.4236/wjcd.2014.41004.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Guo, D.C., Papke, C.L., He, R. and Milewicz, D.M. (2006) Pathogenesis of thoracic and abdominal aortic aneurysm. Annals of the New York Academy of Science, 1085, 339-352.
[2] Libby, P. (2006) Inflammation and cardiovascular disease mechanisms. The American Journal of Clinical Nutrition, 83, 456S-460S.
[3] Lindholt, J.S. and Shl, G.P. (2006) Chronic inflammation, immune response, and infection in abdominal aortic aneurysms. European Journal of Vascular Surgery, 31, 453-463.
[4] Fong, I.W. (2003) Chlamydia pneumoniae and the cardiovascular system. In: Infections and the Cardiovascular System: New Perspectives, Kluwer Academic/Plenum Publishers, New York, 121-156.
[5] Haranaga, S., Yamaguchi, H., Friedman, H., Izumi, S. and Yamamoto, Y. (2001) Chlamydia pneumoniae infects and multiplies in lymphocytes in vitro. Infection and Immunity, 69, 7753-7759.
[6] Edvinsson, M., Thelin, S., Hjelm, E., Friman, G. and Nystrom-Rosander, C. (2010) Persistent chlamydophila pneumoniae infection in thoracic aortic aneurysm and aortic dissection? Upsala Journal of Medical Sciences, 115, 181-186.
[7] Kol, A., Sukhova, G.K., Lichtmanm, A.H. and Libby, P. (1998) Chlamydial heat shock protein 60 localizes in human atheroma and regulates macrophage tumor necrosis factor-alpha and matrix metalloproteinase expression. Circulation, 28, 300-307.
[8] Higuchi, M.L., Reis, M.M., Sambiase, N.V., Palomino, S.A.P. Castelli, J.B., Gutierrez, P.S., Aiello, V.D. and Ramires, J.A.F. (2003) Co-infection with Mycoplasma pneumoniae and Chlamydia pneumoniae in ruptured plaques associated with acute myocardial infarction. Arquivos Brasileiros de Cardiologia, 81, 12-22.
[9] Higuchi, M.L., Gutierrez, P.S., Bezerra, H.G., Palomino, S.A., Aiello, V.D., Silvestre, J.M, Libby, P. and Ramires, J.A. (2002) Comparison between adventitial and intimal inflammation of ruptured and nonruptured atherosclerotic plaques in human coronary arteries. Arquivos Brasileiros de Cardiologia, 79, 20-24.
[10] Momiyama, Y., Ohmori, R., Taniguchi, H., Nakamura, H. and Ohsuzu, F. (2004) Association of Mycoplasma pneumoniae infection with coronary artery disease and its interaction with chlamydial infection. Atherosclerosis, 176, 139-144.
[11] Maia, I.L., Nicolau, J.C., Machado, M. de N., Maia, L.N., Takakura, I.T., Rocha, P.R., Cordeiro, J.A. and Ramires, J.A.F. (2009) Prevalence of Chlamydia pneumoniae and Mycoplasma pneumoniae in different forms of coronary disease. Arquivos Brasileiros de Cardiologia, 92, 405-411.
[12] Damy, S.B., Higuchi, M.L., Timenetsky, J., Reis, M.M., Palomino, S.A., Ikegami, R.N., Santos, F.P., Osaka, J.T. and Figueiredo, L.P. (2009) Mycoplasma pneumoniae and/ or Chlamydophila pneumoniae inoculation causing different aggravations in cholesterol-induced atherosclerosis in apoE KO male mice. BMC Microbiology, 9,194.
[13] Roggério, A., Sambiase, N.V., Palomino, S..A.P., de Castro, M.A., da Silva, E.S., Stolf, N.G. and de Lourdes Higuchi, M. (2013) Correlation of bacterial coinfection versus matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 expression in aortic aneurysm and atherosclerosis. Annals of Vascular Surgery, 27, 964-971.
[14] Kaisho, T. and Akira, S. (2006) Toll-like receptor function and signaling. Journal of Allergy and Clinical Immunology, 117, 979-987.
[15] Cao, F., Castrillo, A., Tontonoz, P., Re, F. and Byrne, G.I. (2007) Chlamydia pneumoniae-induced macrophage foam cell formation is mediated by Toll-like receptor 2. Infection and Immunity, 75, 753-759.
[16] Ashida, K., Miyazaki, K., Takayama, E., Tsujimoto, H., Ayaori, M., Yakushiji, T., Iwamoto, N., Yonemura, A., Isoda, K., Mochizuki, H., Hiraide, H., Kusuhara, M. and Ohsuzu, F. (2005) Characterization of the expression of TLR2 (toll-like receptor 2) and TLR4 on circulating monocytes in coronary artery disease. Journal of Atherosclerosis and Thrombosis, 12, 53-60.
[17] Shimizu, T., Kida, Y. and Kuwano, K. (2005) A dipalmitoylated lipoprotein from Mycoplasma pneumoniae activates NF-kappa B through TLR1, TLR2, and TLR6 Journal of Immunology, 175, 4641-4646.
[18] Ishiyama, J., Taguchi, R., Yamamoto, A. and Murakami, K. (2010) Palmitic acid enhances lectin-like oxidized LDL receptor (LOX-1) expression and promotes uptake of oxidized LDL in macrophage cells. Atherosclerosis, 209, 118-124.
[19] Wassef, M., Baxter, B.T., Chisholm, R.L., Dalman, R.L., Fillinger, M.F., Heinecke, J., Humphrey, J.D., Kuivaniemi, H., Parks, W.C., Pearce, W.H., Platsoucas, C.D., Sukhova, G.K., Thompson, R.W., Tilson, M.D. and Zarins, C.K. (2001) Pathogenesis of abdominal aortic aneurysms: A multidisciplinary research program supported by the National Heart, Lung, and Blood Institute. Journal of Vascular Surgery, 34, 730738
[20] Triantafilou, M., Gamper, F.G., Lepper, P.M. Mouratis, M.A., Schumann, C., Harokopakis, E., Schifferle, R.E., Hajishengallis, G. and Triantafilou, K. (2007) Lipopolysaccharides from atherosclerosis-associated bacteria antagonize TLR4, induce formation of TLR2/1/CD36 complexes in lipid rafts and trigger TLR2-induced inflammatory responses in human vascular endothelial cells. Cellular Microbiology, 9, 2030-2039.
[21] Wang, S.S., Tondella, M.L., Bajpai, A., Mathew, A.G., Mehranpour, P., Li, W., Kacharava, A.G., Fields, B.S., Austin, H. and Zafari, A.M. (2007) Circulating Chlamydia pneumoniae DNA and advanced coronary artery disease. International Journal of Cardiology, 118, 215-219.
[22] Shi, Y. and Tokunaga, O. (2002) Chlamydia pneumoniae and multiple infections in the aorta contribute to atherosclerosis. Pathology International, 52, 755-763.
[23] Hoymans, V.Y., Bosmans, J.M,, Ursi, D., Martinet, W., Wuyts, F.L., Van Marck, E., Altwegg, M., Vrints, C.J. and Ieven, M.M. (2004) Immunohistostaining assays for detection of Chlamydia pneumoniae in atherosclerotic arteries indicate cross-reactions with nonchlamydial plaque constituents. Journal of Clinical Microbiology, 42, 3219-3224.
[24] Pierri, H., Higuchi-dos-Santos, M.H., Higuchi, M. de L, Palomino, S., Sambiase, N.V., Demarchi, L.M., Rodrigues, G.H., Nussbacher, A., Ramires, J.A. and Wajngarten, M. (2006) Density of Chlamydia pneumoniae is increased in fibrotic and calcified areas of degenerative aortic stenosis. International Journal of Cardiology, 108, 43-47.
[25] Kuo, C.C., Gown, A.M., Benditt, E.P. and Grayston, J.T. (1993) Detection of Chlamydia pneumoniae in aortic lesions of atherosclerosis by immunocytochemical stain. . Arteriosclerosis, Thrombosis, and Vascular Biology, 13, 1501-1504
[26] Juvonen, T., Laurila, A., Alakarppa, H., Lounatmaa, K., Surcel, H.M., Leinonen, M., Kairaluoma, M.I. and Saikku, P. (1997) Demonstration of Chlamydia pneumoniae in the walls of abdominal aortic aneurysms. Journal Vascular Surgery, 25, 499-505.
[27] Nystrom-Rosander, C., Edvinsson, M., Thelin, S., Hjelm, E. and Friman, G. (2006) Chlamydophila pneumonia: Specific mRNA in aorta ascendens in patients undergoing coronary artery by-pass grafting. Scandinavian Journal of Infectious Diseases, 38, 758-763.
[28] Sodeck, G., Domanovits, H., Khanakah, G., Schillinger, M., Thalmann, M., Bayegan, K., Schoder, M., Grabenwoeger, M., Hoelzenbein, T., Boehmig, G., Laggner, A.N. and Stanek, G. (2004) The role of Chlamydia pneumoniae in human aortic disease-a hypothesis revisited. European Journal of Vascular and Endovascular Surgery, 28, 547-552.
[29] Higuchi-Dos-Santos, M.H., Pierri, H., Higuchi, M. de L., Nussbacher, A., Palomino, S., Sambiase, N.V., Ramires, J.A. and Wajngarten, M. (2005) Chlamydia pneumoniae and Mycoplasma pneumoniae in calcified nodes of stenosed aortic valves. Arquivos Brasileiros de Cardiologia, 84, 443-448.
[30] Gois, J.M., Higuchi, M.L., Reis, M.M., Diament, J., Sousa, J.M., Ramires, J.A.F. and Oliveira, S.A. (2006) Infectious agentes, inflammation and growth factors. How do they interact in the progression or stabilization of mild human atherosclerotic lessions? Annals of Vascular Surgery, 20, 638-645.
[31] Higuchi, M.L., Sambiase, N.V., Palomino, S., Gutierrez, P., Demarchi, L.M., Aiello, V.D. and Ramires, J.A.F. (2000) Detection of Mycoplasma pneumoniae and Chlamydia pneumoniae in ruptured atherosclerotic plaques. Brazilian Journal of Medical and Biological Research, 33, 1023-1026.
[32] Higuchi, M.L., Santos, M.H., Roggério, A., Kawakami, J.T., Bezerra, H.G. and Canzian, M. (2006) A role for archaeal organisms in development of atherosclerotic vulnerable plaques and myxoid matrices. Clinics, 61, 473-478.
[33] Ravnskov, U. and McCully, K. (2009) Review and Hypothesis: Vulnerable plaque formation from obstruction of Vasa vasorum by homocysteinylated and oxidized lipoprotein aggregates complexed with microbial remnants and LDL autoantibodies. Annals of Clinical Laboratory Science, 39, 3-16.
[34] Ravnskov, U. and McCully, K.S. (2012) Infections may be causal in the pathogenesis of atherosclerosis. The American Journal of the Medical Sciences, 344, 391-394.
[35] Galkina, E. and Ley, K. (2009) Immune and inflammatory mechanisms of atherosclerosis. Annual Review of Immunolog, 27,165-197.
[36] Armant, M.A. and Fenton, M.J. (2002) Toll-like receptors: A family of pattern-recognition receptors in mammals. Genome Biology, 3.
[37] O’Neill, L.A. (2006) How toll-like receptors signal: What we know and what we don’t know. Current Opinion in Immunology, 18, 3-9.
[38] O’Neill, L.A., Bryant, C.E. and Doyle, S.L. (2009) Therapeutic targeting of toll-like receptors for infectious and inflammatory diseases and cancer. Pharmacological Reviews, 61, 177-197.
[39] O’Neill, L.A. (2006) Targeting signal transduction as a strategy to treat inflammatory diseases. Nature Reviews Drug Discovery, 5, 549-563.
[40] Laflamme, N., Echchannaoui, H., Landmann, R. and Rivest, S. (2003) Cooperation between toll-like receptor 2 and 4 in the brain of mice challenged with cell wall components derived from gram-negative and gram-positive bacteria. European Journal of Immunology, 33, 1127-1138.
[41] Shimizu, T., Kida, Y. and Kuwano, K. (2007) Triacylated lipoproteins derived from Mycoplasma pneumoniae activate nuclear factor-κB through toll-like receptors 1 and 2. Immunology, 121, 473-483.
[42] Wu, Q., Martin, R.J., LaFasto, S., Efaw, B.J., Rino, J.G., Harbeck, R.J. and Chu, H.W. (2008) Toll-like receptor 2 down-regulation in established mouse allergic lungs contributes to decreased mycoplasma clearance. American Journal of Respiratory and Critical Care Medicine, 177, 720-729.
[43] Moon, S.K., Woo, J.I., Lee, H.Y., Park, R., Shimada, J., Pan, H., Gellibolian, R. and Lim, D.J. (2007) Toll-like receptor 2-dependent NF-κB activation is involved in nontypeable Haemophilus influenzae-induced monocyte chemotactic protein 1 up-regulation in the spiral ligament fibrocytes of the inner ear. Infection and Immunity, 75, 3361-3372.
[44] Prebeck, S., Kirschning, C., Dürr, S., da Costa, C., Donath, B., Brand, K., Redecke, V., Wagner, H. and Miethke, T. (2001) Predominant role of toll-like receptor 2 versus 4 in Chlamydia pneumoniae-induced activation of dendritic cells. Journal of Immunology, 167, 3316-3323.
[45] Mueller, M., Postius, S., Thimm, J.G., Gueinzius, K., Muehldorfer, I. and Hermann, C. (2004) Toll-like receptors 2 and 4 do not contribute to clearance of Chlamydophila pneumoniae in mice, but are necessary for the release of monokines. Immunobiology, 209, 599-608.
[46] Ikeda, H., Sasaki, M., Ishikawa, A., Sato, Y., Harada, K., Zen, Y., Kazumori, H. and Nakanuma, Y. (2007) Interaction of toll-like receptors with bacterial components induces expression of CDX2 and MUC2 in rat biliary epithelium in vivo and in culture. Laboratory Investigation, 87, 559-571.
[47] Yang, X., Coriolan, D., Schultz, K., Golenbock, D.T. and Beasley, D. (2005) Toll-like receptor 2 mediates persistent chemokine release by Chlamydia pneumoniae-infected vascular smooth muscle cells. Arteriosclerosis, Thrombosis, and Vascular Biology, 25, 2308-2314.
[48] de Graaf, R., Kloppenburg, G., Kitslaar, P.J., Bruggeman, C.A. and Stassen, F. (2006) Human heat shock protein 60 stimulates vascular smooth muscle cell proliferation through toll-like receptors 2 and 4. Microbes and Infection, 8, 1859-1865.
[49] Doherty, T.M., Fisher, E.A. and Arditi, M. (2006) TLR signaling and trapped vascular dendritic cells in the development of atherosclerosis. Trends in Immunology, 27, 222-227.

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