Severity of carotid atherosclerosis unrelated to Chlamydia pneumoniae infection in acute ischemic stroke patients: a clinicopathological study

Chlamydia pneumoniae and stroke: is there a direct relationship?

OBJECTIVE

To investigate the possible relationship between atherothrombotic stroke and Chlamydia pneumoniae.

METHOD

150 patients with carotid atherothrombosis were enrolled. The casuistic was divided in three groups: ischemic stroke (IS): 65 patients; transient ischemic attack (TIA): 26 patients; and control: 59. The IS or TIA onset was up to 30 days from the beginning of the study. Carotid atheromatoses was diagnosed by Doppler-ultrasonography. Patients with cardioembolic risk or non-atherothrombotic origin were excluded. Comparisons were done between the three groups, and within each group according to the different age sub-groups, to the main arteries affected, and to the atherogenic risk factors. Bacteria detection was done using polimerase chain reaction.

RESULTS

Only one patient tested positive for C. pneumoniae belonging to the control group.

CONCLUSION

These results do not suggest that C. pneumoniae participated in the onset of IS or TIA or that it has a role in carotid plaque destabilization.

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

BACKGROUND

Chamydophila 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).

RESULTS

The 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).

CONCLUSION

Inoculation 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.

The interface between stroke and infectious disease: infectious diseases leading to stroke and infections complicating stroke

It is well established that several infectious diseases can directly lead to ischemic or hemorrhagic stroke during their course. It appears possible that common viral and bacterial infections can increase the susceptibility to stroke by promoting atherosclerosis, inflammation, and local thrombosis. Stroke commonly leads to disruption of protective mechanisms against infection and induces a cascade of anti-inflammatory and immunosuppressive reactions, which greatly increases the risk of infection. The social and economic costs of post-stroke infections and their impact on stroke morbidity and outcome are dramatic. Understanding the pathophysiologic links between stroke and infection is therefore of paramount importance, and effective preventive strategies to reduce the risk of infection are needed. This article summarizes current clinical and experimental data regarding the interactions between stroke and infection and outlines possible targets for therapeutic intervention.