Biomarkers and location of atherosclerosis: Matrix metalloproteinase-2 may be related to intracranial atherosclerosis

Search for Reliable Circulating Biomarkers to Predict Carotid Plaque Vulnerability

Atherosclerosis is responsible for 20% of ischemic strokes, and the plaques from the internal carotid artery the most frequently involved. Lipoproteins play a key role in carotid atherosclerosis since lipid accumulation contributes to plaque progression and chronic inflammation, both factors leading to plaque vulnerability. Carotid revascularization to prevent future vascular events is reasonable in some patients with high-grade carotid stenosis. However, the degree of stenosis alone is not sufficient to decide upon the best clinical management in some situations. In this context, it is essential to further characterize plaque vulnerability, according to specific characteristics (lipid-rich core, fibrous cap thinning, intraplaque hemorrhage). Although these features can be partly detected by imaging techniques, identifying carotid plaque vulnerability is still challenging. Therefore, the study of circulating biomarkers could provide adjunctive criteria to predict the risk of atherothrombotic stroke. In this regard, several molecules have been found altered, but reliable biomarkers have not been clearly established yet. The current review discusses the concept of vulnerable carotid plaque, and collects existing information about putative circulating biomarkers, being particularly focused on lipid-related and inflammatory molecules.

Are Genetic Variants Associated with the Location of Cerebral Arterial Lesions in Stroke Patients?

BACKGROUND

Genetic variants may play a role in determining the location of cerebral atherosclerosis. We aimed to investigate the association between RNF213, MMP2, and genetic polymorphisms linked to vascular tortuosity with the location of cerebral arterial atherosclerosis.

METHODS

A prospective case-control study was conducted on patients with ischemic stroke and age- and sex-matched stroke-free controls. The stroke patients were categorized into those with intracranial artery atherosclerosis (ICAS), extracranial artery atherosclerosis (ECAS), and small vessel occlusion (SVO). Six single nucleotide polymorphisms (SNPs) including rs2118181 (FBN1), rs2179357 (SLC2A10), rs1036095 (TGFBR2), rs243865 (MMP2), rs1800470 (TGFB1), and rs112735431 (RNF213) were analyzed with the TaqMan Genotyping Assay, and the distribution of genotypes across groups was compared.

RESULTS

None of the 6 SNPs were associated with stroke on comparing the 449 stroke patients (71 with ECAS, 169 with ICAS, and 209 with SVO) to the 447 controls. In the subgroup analysis, the adjusted odds ratios (aORs) for age and sex indicated a significant association between rs112735431 and ICAS in the allele comparison analysis and in the additive and dominant model analyses. rs112735431 was associated with anterior circulation involvement and increased burden of cerebral atherosclerosis. rs2179357 was significantly associated with ICAS in the recessive model analysis, and rs1800470 was significantly associated with ECAS in the recessive model analysis when compared to controls.

CONCLUSION

rs112735431 was associated with ICAS and increased atherosclerosis burden in Korean stroke patients. Further studies are needed to elucidate the role of rs112735431 and to confirm the association of rs2179357 and rs1800470 with cerebral atherosclerosis.

Diagnostic Significance of Plasma Levels of Novel Adipokines in Patients With Symptomatic Intra- and Extracranial Atherosclerotic Stenosis

Background: Adipokines have been proven to be associated with atherosclerotic diseases such as ischemic stroke and coronary heart disease. The role of novel adipokines in the development of symptomatic intracranial atherosclerotic stenosis (sICAS) and extracranial atherosclerotic stenosis (sECAS) has not yet been investigated. This study aimed to evaluate the plasma levels of novel adipokines in patients with sICAS and sECAS and their associations with the prognosis of sICAS groups.

Methods: A total of 134 patients with acute ischemic stroke attribute to large-artery atherosclerosis (LAA) and 66 age- and sex-matched controls without atherosclerotic stenosis (NCAS) were included in this study. The LAA group was further sub-classified as sICAS (n = 102) and sECAS (n = 32) according to the location of atherosclerosis. Demographics, clinical parameters, angiographical features and plasma levels of novel adipokines (apelin, visfatin, omentin, RBP-4) were assayed and compared among groups.

Results: LAA patients had significantly lower levels of omentin [39.92 (30.74–52.61) ng/ml vs. 54.42 (34.73–79.91) ng/ml, P < 0.001] and visfatin [11.32 (7.62–16.44) ng/ml vs. 13.01 (9.46–27.54) ng/ml, P < 0.001] than those in the NCAS group. Multiple logistic regression analysis identified that the lowest tertile of omentin was independently associated with LAA (OR, 3.423; 95% CI, 1.267–9.244, when referenced to the third tertile). Levels of omentin, visfatin and RBP-4 showed no significant difference between sICAS and sECAS groups. However, median concentrations of apelin were lower in sECAS [84.94 (46.88–130.41) ng/mL) than in sICAS [118.64 (93.22–145.08) ng/mL, P = 0.002] and NCAS [114.38 (80.56–162.93) ng/mL, P = 0.004]. Logistic regression analysis showed that the lowermost tertile of apelin was independently associated with sECAS (OR, 5.121; 95% CI, 1.597–16.426) when adjusted for risk factors. As for sICAS patients, spearman coefficient analysis showed no significant correlation between these four adipokines and the severity of sICAS or the number of vessels with intracranial stenoses. Patients with severe stroke had lower levels of apelin (P = 0.005), while the other three adipokines showed no such difference. During follow up, no difference was found between these four novel adipokines and short- and long-term outcome of sICAS.

Conclusions: Lower levels of omentin are independent biomarkers of LAA while low apelin plasma levels seem to be risk factors of sECAS.

Vitamin D supplementation has no effect on matrix metalloproteinases-2, -9, and tissue inhibitor matrix metalloproteinase-1 in subjects with metabolic syndrome: A pilot study

The present randomized, double-blind, placebo controlled study aimed to evaluate the effect of vitamin D supplementation on matrix metalloproteinases-2, -9 (MMP-2 and MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in subjects with metabolic syndrome. Forty-six eligible subjects were randomly assigned to either vitamin D or placebo groups for 16 weeks. The participants were asked to take 50,000 IU vitamin D or matching placebo every week. Metabolic and anthropometric indices, serum MMP-2, MMP-9, TIMP-1 and high-sensitivity C-reactive protein (hsCRP) were assessed before and after intervention. Moreover, dietary intake, sun exposure and physical activity were also determined. The trial was registered at http://www.irct.ir (No. IRCT201409033140N14). Participants were 40.20 ± 4.60 y and 45.50% males. Compared to the baseline values, MMP-9 and TIMP-1 concentrations were decreased after 16 weeks in the intervention group (p = 0.03 and p = 0.04, respectively). However, the changes of MMP-2, MMP-9, TIMP-1 and hsCRP in the intervention group were not significant compared to the placebo group (p > 0.05). Furthermore, the metabolic or anthropometric indices between two study groups remained unchanged (p > 0.05). The findings of the present study demonstrated no effect of vitamin D supplementation on MMP-2, MMP-9 and TIMP-1 concentrations in subjects with metabolic syndrome. However, there is a need for more longitudinal trials to investigate the role of vitamin D on atherosclerosis and cardiovascular diseases in subjects with metabolic syndrome.

Cinnamaldehyde attenuates atherosclerosis via targeting the IκB/NF-κB signaling pathway in high fat diet-induced ApoE−/− mice

Cinnamaldehyde is a flavor isolated from the bark of Cinnamomum cassia Presl and exerts anti-inflammation effects in various diseases.

Intracranial Atherosclerosis Burden and Stroke Recurrence for Symptomatic Intracranial Artery Stenosis (sICAS)

Intracranial atherosclerosis burden is an arising key index for the risk and prognosis for Intracranial Atherosclerosis Stenosis (ICAS). The present study estimated one-year prognosis for patients of symptomatic ICAS with different degrees of intracranial atherosclerosis burden (ICASB) and identified whether the category of multiple and single acute infarction was associated with atherosclerosis burden. A total of 2864 consecutive patients, from 22 hospitals across China, who experienced an acute cerebral ischemia <7 days after onset of symptoms were evaluated. All patients underwent magnetic resonance angiography, and the degree of intracranial stenosis with the ICASB was calculated. The patients were categorized into three groups according to ICASB grading: <4, 4-5 and >5scores. Multivariate Cox proportional hazards regression models were used to estimate the impact of the hazard ratios(HR) of the putative determinants of recurrent stroke in one year. In the groups with ICASB 4-5 and ICASB >5scores recurrent stroke were significantly higher than the other (P<0.0001). On multivariate logistic analysis, ICASB (4-5) indicated more stroke recurrence at 12 months (adjusted hazard ratio, 1.96; 95% confidence interval, 1.08-3.56; P=0.027), compared to the ICASB<4scores and >5 groups (P<0.001). Moreover, proportion of single and multiple infarction lesions differs with different ICASB. Multiple lesions were related with higher of ICASB(P<0.001). Intracranial atherosclerosis burden was associated with recurrent stroke at 12 months. Multiple infarction lesions were associated with higher ICASB score which indicate higher risk of recurrent.

Intracranial atherosclerotic disease

Intracranial atherosclerosis (ICAS) is a progressive pathological process that causes progressive stenosis and cerebral hypoperfusion and is a major cause of stroke occurrence and recurrence around the world. Multiple factors contribute to the development of ICAS. Angiography imaging techniques can improve the diagnosis of and the selection of appropriate treatment regimens for ICAS. Neither aggressive medication nor endovascular interventions can eradicate stroke recurrence in patients with ICAS. Non-pharmacological therapies such as remote ischemic conditioning and hypothermia are emerging. Comprehensive therapy with medication in combination with endovascular intervention and/or non-pharmacological treatment may be a potential strategy for ICAS treatment in the future. We summarized the epidemiology, pathophysiological mechanisms, risk factors, biomarkers, imaging and management of ICAS.

High neutrophil to lymphocyte ratios predict intracranial atherosclerosis in a healthy population

BACKGROUND AND AIMS

Although atherosclerosis has been shown to be an inflammatory disease, intracranial atherosclerosis (ICAS) has not been well addressed. The purpose of this study was to evaluate the relationship between the neutrophil to lymphocyte ratio (NLR) and the presence of ICAS lesions in a generally healthy population.

METHODS

A consecutive series of subjects, who voluntarily visited for health check-ups between January 2006 and December 2013, were selected. Brain magnetic resonance imaging, brain magnetic angiography (MRA), and blood cell count data were assessed. ICAS was defined as an occlusion or more than 50% stenosis of intracranial vessels, as observed on brain MRA images. NLR was calculated based on absolute neutrophil and lymphocyte counts.

RESULTS

A total of 2842 subjects were evaluated, and 76 ICAS cases were found. The median NLR was 1.52 [1.17-2.01]. In multivariate analysis, NLR remained an independent predictor of ICAS [adjusted OR (aOR) = 1.72, 95% confidence interval (CI) = 1.01-2.95, p = 0.048]. Age (aOR = 1.08, 95% CI = 1.05-1.11, p < 0.001) and hypertension (aOR = 1.81, 95% CI = 1.11-2.94, p = 0.017) were also significant factors for ICAS independent of NLR. Regarding ICAS burdens, NLR was significantly higher when the number of ICAS lesions (p = 0.017) or occlusive ICAS lesions (p = 0.005) was increased in a dose-response manner.

CONCLUSIONS

A high NLR was associated with both prevalence and burdens of ICAS in a healthy population.

Effect of Paeotang on tumor necrosis factor α-induced vascular inflammation in human umbilical vein endothelial cells

OBJECTIVE

To investigate whether Paeotang (10-50 μg/mL) suppresses tumor necrosis factor α (TNF-α)-induced vascular inflammatory processes in human umbilical vein endothelial cells (HUVEC).

METHODS

The ingredients composed of Paeotang include Glycyrrhiza glabra, Zingiber officinale, Cinnamomum zeylanuicum, Salvia miltiorrhiza, Prunus persica, Paeonia szechuanica, Poria cocos and Cynanchum wilfordii. Herbs were mixed according to equal ratio of weight and ground into a crude powder. The effect of Paeotang on the expression of cell adhesion molecules and protective role in HUVEC stimulated by TNF-α were evaluated.

RESULTS

Pretreatment with Paeotang decreased TNF-α-induced adhesion of HL-60 monocytic cells, as well as protein and mRNA expressions of intracellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and endothelial-selectin (E-selectin). Paeotang also dose-dependently inhibited TNF-α-induced matrix metalloproteinase-2 and -9 expressions. Paeotang significantly decreased TNF-α-induced intracellular reactive oxygen species (ROS) production. The Western blot and immunofluorescence analysis showed that Paeotang suppressed the translocation of p65 nuclear factor κB (NF-κB) to the nucleus. In addition, Paeotang inhibited the TNF-α-induced degradation of NF-κB inhibitor α (IκB-α) and by inhibiting the phosphorylation of IκB-α. Furthermore, pretreatment of Paeotang increased the heme oxygenase 1 (HO-1) and nuclear factor erythroid-2-related factor 2 (Nrf2) protein expression in HUVECs stimulated TNF-α. HO-1 was inhibited by Sn-protoporphyrin, HO-1 inhibitor, and increased by cobalt protopophyrin, HO-1 inducer. Furthermore, HO-1 induction was increased by single processing of Paeotang in a dose-dependent manner.

CONCLUSION

These data suggest that Paeotang might be a benefificial therapeutic in vascular inflflammation through regulation of Nrf2-mediated HO-1 expression and inhibition of ROS/NF-κB signaling pathway. Thus, Paeotang maybe serve as a potential anti-atherogenic agent.

Regulation and involvement of matrix metalloproteinases in vascular diseases

Matrix metalloproteinases (MMPs) are a family of zinc dependent endopeptidases whose main function is to degrade and deposit structural proteins within the extracellular matrix (ECM). A dysregulation of MMPs is linked to vascular diseases. MMPs are classified into collagenases, gelatinases, membrane-type, metalloelastase, stromelysins, matrilysins, enamelysins, and unclassified subgroups. The production of MMPs is stimulated by factors such as oxidative stress, growth factors and inflammation which lead to its up- or down-regulation with subsequent ECM remodeling. Normally, excess activation of MMPs is controlled by their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMPs). An imbalance of MMPs and TIMPs has been implicated in hypertension, atherosclerotic plaque formation and instability, aortic aneurysms and varicose vein wall remodeling. Also, recent evidence suggests epigenetic regulation of some MMPs in angiogenesis and atherosclerosis. Over the years, pharmacological inhibitors of MMPs have been used to modify or prevent the development of the disease with some success. In this review, we discuss recent advances in MMP biology, and their involvement in the manifestation of vascular disease.

Differential Vascular Pathophysiologic Types of Intracranial Atherosclerotic Stroke: A High-Resolution Wall Magnetic Resonance Imaging Study

BACKGROUND AND PURPOSE

Intracranial atherosclerotic stroke (ICAS) has various stroke mechanisms, including branch occlusive disease (BOD), subcortical infarcts caused by parent arterial disease occluding the perforator's orifice, and non-BOD, infarcts beyond the subcortical area caused by artery-to-artery embolism. To test whether these 2 types of ICAS had different vascular pathophysiologies, we compared the high-resolution magnetic resonance imaging characteristics between BOD and non-BOD ICAS.

METHODS

Eighty patients with acute infarcts caused by ICAS of proximal middle cerebral artery or basilar artery without carotid/cardiac embolic sources or nonatherosclerotic causes were enrolled (36 BOD and 44 non-BOD patients). The steno-occlusive intracranial artery at the maximal stenosis was analyzed for vascular remodeling and wall enhancement.

RESULTS

BOD had distinct radiological features in terms of vascular morphology and enhancement. BOD showed a milder stenosis than non-BOD (P<0.001). Positive remodeling was more frequently observed in non-BOD than in BOD (P=0.005). Wall area index was also lower in BOD. Plaque enhancement was observed in all but one non-BOD patient and in one fourth of BOD patients (P=0.003). Although both types showed an eccentric enhancement, this enhancement was more frequently distributed in the BOD group on the side where the perforators arose. As the number of asymptomatic intracranial stenosis increased, the degree of stenosis (rho=0.513, P=0.003) increased in the BOD group, whereas enhanced plaque area (rho=0.343, P=0.030) increased in the non-BOD group.

CONCLUSIONS

Our data indicate that BOD is a common and unique form of ICAS, distinct from non-BOD. These 2 types of ICAS have different vascular pathophysiologies in terms of vascular remodeling and plaque characteristics.

Lipoprotein (a) as a risk factor for ischemic stroke: a meta-analysis

OBJECTIVE

Lipoprotein (a) [Lp(a)] harbors atherogenic potential but its role as a risk factor for ischemic stroke remains controversial. We conducted a meta-analysis to determine the relative strength of the association between Lp(a) and ischemic stroke and identify potential subgroup-specific risk differences.

METHODS

A systematic search using the MeSH terms "lipoproteins" OR "lipoprotein a" AND "stroke" was performed in PubMed and ScienceDirect for case-control studies from June 2006 and prospective cohort studies from April 2009 until December 20th 2014. Data from eligible papers published before these dates were reviewed and extracted from previous meta-analyses. Studies that assessed the relationship between Lp(a) levels and ischemic stroke and reported generic data-i.e. odds ratio [OR], hazard ratio, or risk ratio [RR]-were eligible for inclusion. Studies that not distinguish between ischemic and hemorrhagic stroke and transient ischemic attack were excluded. Random effects meta-analyses with mixed-effects meta-regression were performed by pooling adjusted OR or RR.

RESULTS

A total of 20 articles comprising 90,904 subjects and 5029 stroke events were eligible for the meta-analysis. Comparing high with low Lp(a) levels, the pooled estimated OR was 1.41 (95% CI, 1.26-1.57) for case-control studies (n = 11) and the pooled estimated RR was 1.29 (95% CI, 1.06-1.58) for prospective studies (n = 9). Sex-specific differences in RR were inconsistent between case-control and prospective studies. Study populations with a mean age of ≤55 years had an increased RR compared to older study populations. Reported Lp(a) contrast levels and ischemic stroke subtype significantly contributed to the heterogeneity observed in the analyses.

CONCLUSION

Elevated Lp(a) is an independent risk factor for ischemic stroke and may be especially relevant for young stroke patients. Sex-specific risk differences remain conflicting. Further studies in these subgroups may be warranted.

CD59 underlines the antiatherosclerotic effects of C-phycocyanin on mice

The effects of C-phycocyanin (C-PC) on atherosclerosis and the regulatory effects of CD59 gene on anti-atherosclerotic roles of C-PC were investigated. Apolipoprotein E knockout (ApoE(−/−)) mice were randomly divided into four groups: control group, C-PC treatment group, CD59 transfection group and C-PC+CD59 synergy group. The mice were fed with high-fat-diet and treated with drug intervention at the same time. Results showed the atherosclerotic mouse model was successfully established. CD59 was over-expressed in blood and tissue cells. Single CD59 or C-PC could reduce blood lipid levels and promote the expression of anti-apoptotic Bcl-2 but inhibit pro-apoptotic Fas proteins in endothelial cells. The expression levels of cell cycle protein D1 (Cyclin D1) and mRNA levels of cyclin dependent protein kinase 4 (CDK4) in smooth muscle cells were restrained by CD59 and C-PC. CD59 or C-PC alone could inhibit the formation of atherosclerotic plaque by suppressing MMP-2 protein expression. In addition, C-PC could promote CD59 expression. So both CD59 and C-PC could inhibit the progress of atherosclerosis, and the anti-atherosclerotic effects of C-PC might be fulfilled by promoting CD59 expression, preventing smooth muscle cell proliferation and the apoptosis of endothelial cells, reducing blood fat levels, and at last inhibiting the development of atherosclerosis.

Biomarkers for stroke

Background

Major stroke clinical trials have failed during the past decades. The failures suggest the presence of heterogeneity among stroke patients. Biomarkers refer to indicators found in the blood, other body fluids or tissues that predicts physiologic or disease states, increased disease risk, or pharmacologic responses to a therapeutic intervention. Stroke biomarkers could be used as a guiding tool for more effective personalized therapy.

Main Contents

Three aspects of stroke biomarkers are explored in detail. First, the possible role of biomarkers in patients with stroke is discussed. Second, the limitations of conventional biomarkers (especially protein biomarkers) in the area of stroke research are presented with the reasons. Lastly, various types of biomarkers including traditional and novel genetic, microvesicle, and metabolomics-associated biomarkers are introduced with their advantages and disadvantages. We especially focus on the importance of comprehensive approaches using a variety of stroke biomarkers.

Conclusion

Although biomarkers are not recommended in practice guidelines for use in the diagnosis or treatment of stroke, many efforts have been made to overcome the limitations of biomarkers. The studies reviewed herein suggest that comprehensive analysis of different types of stroke biomarkers will improve the understanding of individual pathophysiologies and further promote the development of screening tools for of high-risk patients, and predicting models of stroke outcome and rational stroke therapy tailored to the characteristics of each case.