Increased endothelial expression of intercellular adhesion molecule-1 in symptomatic versus asymptomatic human carotid atherosclerotic plaque

Inflammation and infection in clinical stroke

Stroke has enormous clinical, social, and economic implications, and demands a significant effort from both basic and clinical science in the search for successful therapies. Atherosclerosis, the pathologic process underlying most coronary artery disease and the majority of ischemic stroke in humans, is an inflammatory process. Complex interactions occur between the classic risk factors for atherosclerosis and its clinical consequences. These interactions appear to involve inflammatory mechanisms both in the periphery and in the CNS. Central nervous system inflammation is important in the pathophysiologic processes occurring after the onset of cerebral ischemia in ischemic stroke, subarachnoid hemorrhage, and head injury. In addition, inflammation in the CNS or in the periphery may be a risk factor for the initial development of cerebral ischemia. Peripheral infection and inflammatory processes are likely to be important in this respect. Thus, it appears that inflammation may be important both before, in predisposing to a stroke, and afterwards, where it is important in the mechanisms of cerebral injury and repair. Inflammation is mediated by both molecular components, including cytokines, and cellular components, such as leukocytes and microglia, many of which possess pro- and/or antiinflammatory properties, with harmful or beneficial effects. Classic acute-phase reactants and body temperature are also modified in stroke, and may be useful in the prediction of events, outcome, and as therapeutic targets. New imaging techniques are important clinically because they facilitate dynamic evaluation of tissue damage in relation to outcome. Inflammatory conditions such as giant cell arteritis and systemic lupus erythematosus predispose to stroke, as do a range of acute and chronic infections, principally respiratory. Diverse mechanisms have been proposed to account for inflammation and infection-associated stroke, ranging from classic risk factors to disturbances of the immune and coagulation systems. Considerable opportunities therefore exist for the development of novel therapies. It seems likely that drugs currently used in the treatment of stroke, such as aspirin, statins, and modulators of the renin-angiotensin-aldosterone system, act at least partly via antiinflammatory mechanisms. Newer approaches have included antimicrobial and antileukocyte strategies. One of the most promising avenues may be the use of cytokine antagonism, for example, interleukin-1 receptor antagonist.

Endothelial cell activation is associated with cerebral white matter lesions in patients with cerebrovascular disease

Cerebral MRI scanning frequently shows white matter lesions in elderly people. They are related to cognitive impairment and may result in dementia. Although vascular risk factors are associated with the presence of white matter lesions, the exact pathogenesis remains unclear. Animal studies have indicated involvement of endothelial cells in the pathogenesis of white matter lesions and possibly dementia. We investigated the relation between endothelial cell activation and white matter lesions in individuals with cerebrovascular disease. In 29 patients with an acute stroke (n = 11) or TIAs associated with a symptomatic internal carotid artery stenosis (n = 18), markers of endothelial cell activation such as intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), sE-selectin, and sP-selectin were measured by means of ELISA. All individuals underwent 1.5-T MRI scanning. White matter lesions were rated for the periventricular and the subcortical region separately. Individuals with severe periventricular white matter lesions had higher levels of sP-selectin (245.5 ng/mL vs. 172.7 ng/mL, p = 0.01) and sVCAM-1 (547.8 ng/mL vs. 454.0 ng/mL, p = 0.04) than those without. This association was only found in individuals with a symptomatic carotid artery stenosis. No such association was found for subcortical white matter lesions. We did not detect any relation between sICAM-1 and sE-selectin and white matter lesions. Endothelial cell activation may play a role in the pathogenesis of white matter lesions, especially in periventricular white matter. Possibly, this activation represents the influence of vascular factors on the cerebral endothelium as a prelude to increasingly severe small vessel disease.

Change in saturated fat intake is associated with progression of carotid and femoral intima-media thickness, and with levels of soluble intercellular adhesion molecule-1

BACKGROUND

A high saturated fat (SFA) intake may stimulate progression of atherosclerosis, and may be positively associated with expression of adhesion molecules.

METHODS

In moderately hypercholesterolaemic participants of a dietary intervention study (n=103; 55+/-10 years), we examined associations between reported changes in SFA intake and changes in carotid and femoral intima-media thickness (IMT) and soluble intercellular adhesion molecule-1 (sICAM-1) levels after 2 years. The carotid and femoral IMT was assessed by high-resolution B-mode ultrasound images.

RESULTS

After 2 years, dietary intake of SFA decreased with 1.8+/-2.6% of energy (P<0.01). In the lowest quintile of change in SFA intake (-5.9+/-1.4% of energy), changes in carotid and femoral IMT were +0.03 mm (SEM 0.03) and -0.09 mm (SEM 0.07), respectively, versus +0.10 mm (SEM 0.03), +0.17 mm (SEM 0.07) in the top quintile (+1.6+/-0.7% of energy) (P linear trend 0.07 (carotis), 0.02 (femoralis)). Changes in sICAM-1 were -19.0 ng/nl (SEM 5.6) in the lowest quintile, versus +8.6 ng/ml (SEM 5.3) in the top quintile (P linear trend <0.001), adjusted for baseline level, SFA intake, body mass index, age, changes in intake of fruit, polyunsaturated fat, and dietary cholesterol. Adjustments for changes in established risk factors did not alter these results.

CONCLUSIONS

Decreased SFA intake may reduce progression of atherosclerosis, as assessed by IMT, and is associated with reduced levels of sICAM-1 after 2 years. Further research using randomised placebo-controlled trials is necessary to exclude potential confounding variables and to confirm causality.

Elevation of soluble intercellular adhesion molecule-1 levels in symptomatic and asymptomatic carotid atherosclerosis

OBJECTIVE

Recent data suggest that the increased expression of intercellular adhesion molecule-1 (ICAM-1) in atherosclerotic plaque taken from the carotid bifurcation correlates with the development of neurological symptoms. As a result, the authors sought to compare the serum levels of soluble forms of ICAM-1 (sICAM-1) in patients who were asymptomatic with those who were symptomatic for carotid artery stenosis as well as in patients who were matched in terms of sex, age, and risk factors who did not have carotid artery disease.

METHODS

Using enzyme-linked immunosorbent assay, serum sICAM-1 levels were prospectively determined in 54 patients scheduled to undergo carotid endarterectomy for either symptomatic or asymptomatic high-grade stenosis (> or =60%) and in 5 additional patient controls. Data are expressed as mean +/- standard error of the mean, with significance defined as P < 0.05 using the Mann-Whitney two-tailed test for two-column comparison or analysis of variance and Fisher protected least significant difference test.

RESULTS

Using a univariate model, serum sICAM-1 levels were significantly elevated in patients with carotid artery stenosis as compared with control patients without stenosis (347 +/- 15 ng/ml versus 216 +/- 8.2 ng/ml) (P < 0.01). When the asymptomatic and symptomatic patients with carotid artery stenosis were considered separately, these levels were still elevated relative to those of control patients (asymptomatic [312 +/- 18 ng/ml] and symptomatic [376 +/- 22 ng/ml] patients; P = 0.06 for asymptomatic versus control patients, P < 0.01 for symptomatic versus control patients). Symptomatic patients also had significantly elevated sICAM-1 levels as compared with asymptomatic patients (P < 0.05). Despite the fact that female patients demonstrated higher ICAM-1 levels than male patients (P < 0.05), sex, age, and risk factors such as the presence of hypercholesterolemia, diabetes, hypertension, or a history of smoking did not confound these findings.

CONCLUSION

Levels of sICAM-1 are higher in patients with carotid stenosis than in control patients. Symptomatic patients demonstrate significantly elevated levels as compared with asymptomatic patients. These data support the contention that ICAM-1 is a reliable marker of carotid disease progression and suggest that serum levels may be useful in following certain asymptomatic patients.

Therapeutic potential of dietary phase 2 enzyme inducers in ameliorating diseases that have an underlying inflammatory component

Many diseases associated with ageing have an underlying oxidative stress and accompanying inflammatory component, for example, Alzheimer's disease or atherosclerosis. Reviewed in this manuscript are: the role of oxidative stress in activating the transcription factor nuclear factor kappa B (NFκB), the role of NFκB in activating pro-inflammatory gene transcription, strong oxidants produced by cells, anti-oxidant defense systems, the central role of phase 2 enzymes in the anti-oxidant defense, dietary phase 2 enzyme inducers and evidence that dietary phase 2 enzymes decrease oxidative stress. It is likely that a diet containing phase 2 enzyme inducers may ameliorate or even prevent diseases that have a prominent inflammatory component to them. Research should be directed into the potential therapeutic effects of dietary phase 2 enzyme inducers in ameliorating diseases with an underlying oxidative stress and inflammatory component to them.Key words: Alzheimer's disease, atherosclerosis, diet, glutathione, inflammation, stroke.

Electrochemical monitoring of superoxide anion production and cerebral blood flow: effect of interleukin-1 beta pretreatment in a model of focal ischemia and reperfusion

Conditions associated with systemic infection, such as endotoxinemia, are known to increase the levels of pro-inflammatory cytokines such as interleukin (IL)-1 in the central nervous system. Systemic infection has been shown to be a common preexisting condition in patients with stroke. To examine a possible consequence of systemic infection, we used a novel electrochemical technique, which combines measurement of cerebral blood flow with measurement of superoxide anion concentrations, to examine the effect of pretreatment of pial vasculature with a proinflammatory cytokine, IL-1 beta, on cerebral blood flow and superoxide anion concentration in a rat model of middle cerebral artery occlusion and reperfusion. In addition, neutrophil recruitment was measured using an immunohistochemical technique. Our results indicate that exposure of pial and cerebral vasculature to IL-1 beta significantly accelerates recruitment of neutrophils, reduces cerebral blood flow, and increases superoxide anion concentration at the pial surface during reperfusion. These results support the idea that prior exposure of brain vasculature to IL-1 beta results in acceleration of cerebrovascular injury by accelerating recruitment of neutrophils, which secrete superoxide anion, during reperfusion. This finding has possible implications for the treatment of stroke with reperfusion agents in patients with preexisting infections.

Why do neuroprotective drugs work in animals but not humans?

Many neuroprotective agents that seemed promising in animal studies of ischemic brain injury prove to have no effect when tested in clinical trials, suggesting that fundamental elements of translational research require better definition. A number of modifications have led to improvements in preclinical and human studies since the earliest controlled trials failed to confirm hypotheses suggested by animal data. Continued re-evaluation and sharing of information derived from the laboratory bench or the patient's bedside should eventually lead to effective neuroprotection in acute stroke. Experimental data should be carefully studied to improve the quality of agents coming to clinical trials and to design trial phasing that effectively determines drug safety and efficacy. This article will examine preclinical modeling and its translation to prospective studies of acute stroke therapy and will focus on some potential solutions directed at clinical trial design.