Mycoplasma pneumoniae and/or Chlamydophila pneumoniae inoculation causing different aggravations in cholesterol-induced atherosclerosis in apoE KO male mice

Abstract

BackgroundChamydophila pneumoniae (CP) and/or Mycoplasma pneumoniae (MP) are two bacteria detected in vulnerable atheromas. In this study we aimed to analyze whether CP and/or MP aggravates atherosclerosis induced by cholesterol-enriched diet in C57BL/6 apoE KO male mice. Thirty male apoE KO mice aged eight weeks fed by a diet containing 1% cholesterol until 32 weeks of age were divided into four groups: the first was inoculated with CP (n = 7), the second with MP (n = 12), the third with both CP + MP (n = 5), and the fourth with saline (sham n = 6). The animals were re-inoculated at 36 weeks of age, and sacrificed at 40 weeks of age. Two ascending aorta and one aortic arch segments were sampled. In the most severely obstructed segment, vessel diameter, plaque height, percentage of luminal obstruction and the degree of adventitial inflammation were analyzed. The plaque area/intimal surface ratio was obtained by measuring all three segments. The adventitial inflammation was semiquantified (0 absent, 1 mild, 2 moderate, and 3 diffuse).ResultsThe mean and standard deviation of plaque height, % luminal obstruction, external diameter, the plaque area/intimal surface ratio and the adventitial inflammation values are the following for each group: MP (0.20 +/- 0.12 mm, 69 +/- 26%, 0.38 +/- 0.11 mm, 0.04 +/- 0.04 and 0.22 +/- 0.67), CP (0.23 +/- 0.08 mm, 90 +/- 26%, 0.37 +/- 0.08 mm, 0.04 +/- 0.03, and 0.44 +/- 0.53), MP + CP (18 +/- 0.08 mm, 84 +/- 4.0%, 0.35 +/- 0.25 mm, 0.03 +/- 0.03 and 1.33 +/- 0.82) and sham (0.08 +/- 0.09 mm, 42 +/- 46%, 0.30 +/- 0.10 mm, 0.02 +/- 0.03 and 0.71 ± 0.76). A wider area of plaque/intimal surface was observed in MP + CP inoculated groups (p = 0.07 and 0.06) as well as an increased plaque height in CP (p = 0.01) in comparison with sham group. There was also an increased luminal obstruction (p = 0.047) in CP inoculated group in comparison to sham group. Adventitial inflammation in MP + CP inoculated group was higher than MP, CP and the sham groups (p = 0.02).ConclusionInoculation of CP, MP or both agents in C57BL/6 apoE KO male mice caused aggravation of experimental atherosclerosis induced by cholesterol-enriched diet, with distinct characteristics. CP inoculation increased the plaque height with positive vessel remodeling and co-inoculation of MP + CP caused the highest adventitial inflammation measures.

Biophysical regulation of Chlamydia pneumoniae-infected monocyte recruitment to atherosclerotic foci

“…In vitro , the infection cycle in monocytes/macrophages typically last up to 3 days during which the bacterium triggers the upregulation of a number of genes linked to the development of atherosclerosis, secretion of a plethora of inflammatory cytokines, and increase the expression of endothelial adhesion molecules 15 16 . In addition, infection also alters cholesterol homeostasis 17 , activation of LDL receptor 18 , and induce atherosclerosis in apo-E KO mice 19 . Taken together, these observations suggest that the changes in the physiology of the host cell due to C. pneumoniae infection may contribute to the development of atherosclerosis.…”

Involvement of TLR2 and TLR4, <i>Chlamydophila pneumoniae</i> and <i>Mycoplasma pneumoniae</i> in adventitial inflammation of aortic atherosclerotic aneurysm

“…Also clinical studies have shown increased seropositivity to both Mp and Cp [10,11]. Inoculation of Cp and Mp in ApoE KO mice fed with cholesterol enriched diet caused aggravation of the size atherosclerotic plaques, inflammation or vessel remodeling [12]. In a recent work, we found higher amounts of both Cp and Mp in the adventitia of AAA than in severe aortic non-dilated atherosclerosis [13].…”

Hyperhomocysteinemia, Suppressed Immunity, and Altered Oxidative Metabolism Caused by Pathogenic Microbes in Atherosclerosis and Dementia

“…Experimental atherosclerotic plaques are produced in chickens by Marek's disease herpesvirus (Fabricant et al, 1978 ). C. pneumoniae and M. pneumoniae cause exacerbation of arterial plaques in hypercholesterolemic mice (Damy et al, 2009 ), and C. pneumoniae and influenza virus cause exacerbation of arterial plaques in mini-pigs with hypercholesterolemia (Birck et al, 2011 ).…”