Statin treatment, carotid atherosclerotic plaque macrophage infiltration and circulating inflammatory markers

Cholesterol, carotid artery disease and stroke: what the vascular specialist needs to know

Hypercholesterolemia is a risk factor for carotid artery stenosis and stroke. Statins are the main drugs for the management of hypercholesterolemia and they are strongly recommended by international guidelines for the management of vascular patients. The present review will focus on the associations between cholesterol, carotid artery stenosis and stroke and will cover several topics, including the conservative and perioperative/periprocedural management of carotid patients, the effect of statins on contrast-induced nephropathy developing after endovascular carotid interventions, the role of statin loading prior to endovascular procedures, as well as the indirect beneficial effects of statin treatment on renal function. It will also discuss the topics of statin intolerance and alternative cholesterol-lowering options for statin-intolerant vascular patients. Cholesterol levels play a prognostic role in carotid patients with regards to both short- and long-term stroke and mortality rates. Physicians should keep in mind the pivotal role of cholesterol levels in determining cardiovascular outcomes and the pleiotropic beneficial effects associated with statin use and should not miss the opportunity for cardiovascular risk reduction with aggressive statin treatment.

Inflammation of carotid plaques and risk of cerebrovascular events

Carotid atherosclerotic plaques represent a risk for ischemic stroke. The data indicate that the risk for distal embolization from atherosclerotic lesions in internal carotid arteries is not related only to the degree of stenosis but also to the composition of plaques. The stability of atherosclerotic plaque depends on the thickness of the fibrous cap and plaque hemorrhage. Recent research indicated that the inflammatory activity of atherosclerotic lesions is pivotal in the progression of atherosclerotic plaques. It also promotes the development of unstable atherosclerotic lesions and is related to thromboembolic cerebrovascular complications. Inflammation destabilizes atherosclerotic plaques through the degradation of their fibrotic structure. Inflammation of atherosclerotic plaques was confirmed by histopathologic findings and levels of circulating inflammatory markers which were correlated to the intensity of the inflammation in atherosclerotic lesions. Recently, new techniques like fluorodeoxyglucose positron emission tomography (18-FDG PET) were developed for the identification of inflammation of atherosclerotic lesions in the vessel wall in vivo. Systemic inflammatory markers, particularly interleukins, tumor necrosis factor-alpha and metalloproteinases were shown to be related to the intensity of the inflammatory process in atherosclerotic lesions and the cerebrovascular events. Identification of inflamed atherosclerotic plaques may help to identify unstable atherosclerotic lesions and subjects at high risk for cerebrovascular incidents who need intensive preventive measures including anti-inflammatory medication.

Favourable impact of statin use on diastolic blood pressure levels: analysis of a large database of 24-hour ambulatory blood pressure monitoring

INTRODUCTION

Assumption of lipid-lowering drugs, mostly statins, is recommended at bed-time and evidence demonstrated a strong and independent correlation between night-time blood pressure (BP) and increased risk of cardiovascular events.

AIM

To evaluate the effects of statins on night-time BP levels.

METHODS

We analysed data derived from a large cohort of adult individuals, who consecutively underwent home, clinic and ambulatory BP monitoring at our Unit. All BP measurements were performed and BP thresholds were set according to recommendations from European guidelines. Study population was stratified according to statin use.

RESULTS

We included an overall sample of 5634 adult individuals (women 48.9%, age 60.5 ± 11.6 years, BMI 27.0 ± 4.6 kg/m, clinic BP 144.3 ± 18.4/90.9 ± 12.4 mmHg, 24-h BP 130.7 ± 13.4/79.0 ± 9.7 mmHg), among whom 17.3% received and 82.7% did not received statins. Treated outpatients were older, had higher BMI and prevalence of risk factors and comorbidities than those who were untreated (P < 0.001 for all). Patients treated with statins showed lower DBP levels at all BP measurements, including night-time (67.3 ± 9.4 vs. 70.9 ± 9.7 mmHg; P < 0.001) periods, than those observed in untreated patients. Also, statin use resulted an independent factor associated with 24-h [odds ratio (95% confidence interval): 1.513(1.295-1.767); P < 0.001] and night-time [odds ratio (95% confidence interval): 1.357(1.161-1.587); P < 0.001] BP control, even after adjusting for age, sex, BMI, diabetes, number of antihypertensive drugs (model 1) or presence/absence of antihypertensive treatment (model 2).

CONCLUSION

Statin use was associated with significantly lower DBP levels. These effects were independently observed, even after correction for cardiovascular risk factors and comorbidities, as well as number of antihypertensive drugs.

Cadmium exposure as measured in blood in relation to macrophage density in symptomatic atherosclerotic plaques from human carotid artery

BACKGROUND AND AIMS

The general population is exposed to cadmium through diet and smoking. Cadmium is pro-atherogenic and pro-inflammatory in experimental and observational studies. Cadmium levels in blood and carotid plaque endarterectomies correlate. Cadmium concentrations are much higher in plaque-areas that most frequently rupture. Here we investigated if blood cadmium concentrations are associated with macrophage density and the accumulation of CD14 as indicator of macrophage activation by lipopolysaccharide (LPS) in endarterectomies from patients with symptomatic carotid plaques.

METHODS

Endarterectomies from ninety nine patients were fixed in formalin, embedded in paraffin, serially sectioned and stained for assessment of morphology. As predefined, the two section levels with most prevalent plaque rupture were used for further analyses. Macrophages were assessed as area of staining for CD68 (%). Blood cadmium was measured with ICP-MS.

RESULTS

The CD68 median [25,75 percentiles] from the average of both sections were higher in cadmium tertile 3 than in tertile 1 (9.8 [4.9,16.1] % and 3.8 (0.6,12.4) %, p = 0.017). This difference remained in a multiple linear regression analysis with (10)log meanCD68 as dependent variable and adjustment for sex, age, smoking, statin treatment, index event, time between event and surgery (beta coefficient 0.44 [95% CI 0.05-0.87]. CD14 was not associated with blood cadmium.

CONCLUSIONS

The results showed that blood cadmium was associated with proinflammatory macrophage density in the sections of carotid plaques with most frequent rupture, previously shown to contain most cadmium. No association between cadmium and LPS-mediated macrophage-activation was found. Cadmium exposure may promote plaque inflammation.

Flow cytometry and gene expression profiling of immune cells of the carotid plaque and peripheral blood

OBJECTIVES

The relative contribution of the local vs. peripheral inflammation to the atherothrombotic processes is unknown. We compared the inflammatory status of the immune cells of the carotid plaque with similar cells in peripheral circulation of patients with advanced carotid disease (PCDs).

METHODS

Mononuclear cells (MNCs) were extracted from carotid endarterectomy (CEA) samples by enzymatic digestion and subsequent magnetic cell sorting. The cell surface antigenic expressions, and mRNA expression levels were compared between CEA MNCs and peripheral MNCs, using flow cytometry and RT-PCR techniques.

RESULTS

The percentages of resting MNCs were lower, and activated MNCs, particularly monocytes, were higher in the CEAMNCs, as compared to the peripheral MNCs. The percentages of activated T cells and B cells were higher in the peripheral MNCs of PCDs, than in healthy controls (HCs), but the percentages of activated monocytes did not differ between the two groups. The expression levels of both pro-inflammatory/pro-thrombotic (P(38), JNKB-1, Egr-1 PAI-1, MCP-1, TF, MMP-9, HMGB-1, TNF-α, mTOR) and anti-inflammatory (PPAR-γ, TGF-β) mediators were significantly higher in the CEA MNCs as compared to the peripheral MNCs. Furthermore, MMP-9 and PPAR-γ expression levels were higher in the peripheral MNCs of PCDs than HCs.

CONCLUSION

The inflammatory status is higher in the immune cells of the carotid plaque, as compared to those cells in the peripheral blood. The altered expression levels of both pro-inflammatory/pro-thrombotic and anti-inflammatory mediators in the milieu of the plaque suggest that the balance between these various mediators may play a key role in carotid disease progression.

Statins and noncardiac vascular disease

PURPOSE OF REVIEW

To discuss the beneficial effects of statin treatment in patients with peripheral arterial disease (PAD), abdominal aortic aneurysms (AAAs), atherosclerotic renal artery stenosis (ARAS) and carotid artery disease.

RECENT FINDINGS

Evidence suggests that statins may reduce the progression (or even reverse the development) of carotid artery stenosis and AAAs. Statins also improve several indices (e.g. serum creatinine) and preserve renal function in ARAS. In patients with PAD, statins are associated with improved claudication distance and time, reduced cardiovascular events, and improved graft patency rates should these patients undergo surgery. Finally, statins are associated with improved perioperative and long-term morbidity and mortality rates in all vascular patients whether they undergo surgery or endovascular procedures.

SUMMARY

Routine statin treatment should be implemented for all vascular patients to ensure a reduced progression of their disease, as well as a reduction in cardiovascular events.

Inflammation as a marker for the prediction of internal carotid artery restenosis following eversion endarterectomy--evidence from clinical studies

The role of inflammation is well established in the pathogenesis of atherosclerosis and an increased level of circulating inflammatory markers may predict the future risk of atherosclerosis progression and plaque rupture. C-reactive protein (CRP) identification by hypersensitive methods (high-sensitivity CRP [hsCRP]) has become a clinical and laboratory inflammation marker. Carotid endarterectomy (CEA) is a well-established procedure for carotid stenosis treatment which can reduce stroke rate. Internal carotid artery (ICA) restenosis reduction may be prevented by the anti-inflammatory effect of statins. This review considers the recent findings on the presence of hsCRP and C3 complement concentration and inflammatory plaque composition as well as their effects on ICA restenosis rate, following eversion CEA with emphasis on human studies.

Macrophage infiltration and smooth muscle cells content associated with haptoglobin genotype in human atherosclerotic carotid plaques

We assessed the association between the haptoglobin (Hp) genotype and 2 common indicators of atherosclerotic plaque instability: macrophage infiltration and the smooth muscle cell (SMC) content. A total of 70 consecutive patients who underwent carotid endarterectomy were included in the study. For immunohistochemical study the anti-CD68 and anti-a-actin antibodies were used on adjacent serial sections; 36 plaques from patients with the Hp 1-1 or 2-1 genotype and 34 plaques from patients with the Hp 2-2 genotype were analyzed. The macrophage content (CD68+) was significantly higher in the Hp 2-2 group compared with that in the Hp 1-1 or 2-1 group (P < .001). In plaques from patients with diabetes, the SMC content was significantly lower in the Hp 2-2 group (P = .034). Carotid plaques from diabetic patients with Hp 2-2 genotype had higher macrophage infiltration and lower SMC content. Both parameters are indicators of atherosclerotic plaque instability.

Retrospective analysis of bovine pericardium (Vascu-Guard) for patch closure in carotid endarterectomies

BACKGROUND

It has been shown that patch closure after carotid endarterectomy (CEA) decreases the rate of recurrent stenosis. This study was designed to evaluate the utility of bovine pericardium patch as an option for patch closure after CEA.

METHODS

This retrospective study examined 845 CEAs with bovine patch closure that were performed by the surgeons of Indiana-Ohio Heart, Fort Wayne, IN, between May 2003 and March 2009. The average age of the patients was 72.7 ± 10.6 years and postoperative follow-up was performed using duplex ultrasound at (ideally) 1 month, 6 months, 12 months, and annually thereafter. The average duration of follow-up for this study was 19.2 ± 16.8 months (ranging from 1 day to 72 months). All patients were evaluated for demographics and postoperative medications. Restenosis was categorized in three ways: nonsignificant (0-59% narrowing of the artery), significant (60-79%), or critical (80-99%). A total of 796 arteries were studied at least once during the postoperative period.

RESULTS

None of the postoperative duplex studies revealed occlusion of the endarterectomized artery. At the mean follow-up duration, 323 endarterectomized arteries were studied. In all, 24 arteries (7.43%) had significant stenosis and only two (0.62%) had critical stenosis. These numbers compare favorably with the recurrent restenosis rates of other materials. Additionally, the effect of statins on restenosis rates was studied. We were unable to demonstrate a beneficial effect of postoperative statin therapy on restenosis rates.

CONCLUSION

The use of bovine pericardium for patch closure in CEA yields excellent freedom from residual or recurrent postoperative stenosis and the use of statins postoperatively failed to reduce the likelihood of residual or recurrent stenosis.