Angiogenesis and inflammation in carotid atherosclerosis

Recent advances in proteomic analysis to study carotid artery plaques

Objective

We sought to identify differentially expressed proteins in serum, plasma, and plaque samples of patients with carotid atherosclerotic lesions.

Methods

We performed a systematic review of the proteomic profile of serum, plasma, and plaque samples of patients with carotid artery disease. We included full-length peer-reviewed studies of adult humans and reported them using PRISMA guidelines. The quality of the design and content of the articles included in the review was assessed using the Newcastle-Ottawa scale.

Results

We included six peer-reviewed articles reporting protein expression in serum, plasma, or plaque samples from patients with carotid atherosclerosis. Three were single-center cross-sectional studies, two were single-center case-control studies, and one was a single-center cohort study. Thirty-six proteins were found to be expressed differentially when comparing samples from healthy subjects and individuals with diseased carotid vessels and between patients with symptomatic and asymptomatic carotid artery atherosclerotic lesions. Some of these were shown to be related to inflammatory or anti-inflammatory pathways in atherogenesis. CD5L and S100A12 were both found to be upregulated in patients with unstable plaque, the former owing to its anti-inflammatory properties and the latter for its pro-oxidant effects in atherosclerosis. ACTB is involved in cellular structure and integrity and was found to be downregulated in patients with ruptured carotid plaques.

Conclusions

Atherosclerotic carotid disease places the patient at increased risk of ischemic neurological events. Proteomics may help to understand their pathophysiological processes and can identify differential protein expression in blood samples from healthy subjects and patients with carotid artery plaques. This patient-centered approach will allow for the timely identification of individuals at higher risk of experiencing stroke.

The protective effect of HOXA5 on carotid atherosclerosis occurs by modulating the vascular smooth muscle cell phenotype

The phenotypic change of vascular smooth muscle cells (VSMCs) from a contractile to a synthetic form is a key player in atherogenic processes. Homeobox A5 (HOXA5), a transcription factor of the homeobox gene family, has been shown to regulate cell differentiation and morphogenesis. The present study was designed to clarify the involvement of HOXA5 in VSMC phenotypic transition in carotid atherosclerosis (CAS). Activated VSMCs in vitro and ApoE^-/- mice in vivo were employed to determine HOXA5's function. Results showed that both the mRNA and protein expression levels of HOXA5 were decreased in platelet-derived growth factor-BB (PDGF-BB)-induced VSMCs. Overexpression of HOXA5 suppressed VSMC conversion from a contractile to a synthetic type in the presence of PDGF-BB, as evidenced by increased contractile markers (calponin, α-SMA and SM22α) along with decreased synthetic markers (vimentin, PCNA and thrombospondin). PDGF-BB-induced proliferation and migration of VSMCs were recovered by HOXA5. Knockdown of HOXA5 had the opposite effect on VSMCs. In vivo, a CAS model was established using ApoE^-/- mice fed with a Western-type diet and placing a perivascular carotid collar. We observed a significant reduction in HOXA5 in the carotid arteries of CAS mice. Similar to the in vitro results, HOXA5 overexpression reduced neointimal hyperplasia and plaque formation and inhibited VSMC dedifferentiation and migration. Furthermore, PPARγ was also downregulated in vitro and in vivo, and its antagonist GW9662 reversed HOXA5-mediated inhibition of VSMC dedifferentiation and migration. In summary, we suggest that HOXA5 protects against CAS progression by inhibiting VSMC dedifferentiation through activation of PPARγ.

Circulating MicroRNAs as Novel Biomarkers of Stenosis Progression in Asymptomatic Carotid Stenosis

Background and Purpose—

Progression of asymptomatic carotid artery stenosis (ACAS) in patients with >50% luminal narrowing is considered a potential risk factor for ischemic stroke; however, subclinical molecular biomarkers of ACAS progression are lacking. Recent studies suggest a regulatory function for several microRNAs (miRNAs) on the evolution of carotid plaque, but its role in ACAS progression is mostly unknown. The aim of our study was to investigate a wide miRNA panel in peripheral blood exosomes from patients with ACAS to associate circulating miRNA expression profiles with stenosis progression.

Methods—

The study included 60 patients with ACAS carrying >50% luminal narrowing. First, miRNA expression profiles of circulating exosomes were determined by Affymetrix microarrays from plasma samples of 16 patients from the cohort. Second, those miRNAs among the most differentially expressed in patients with ACAS progression were quantified by real-time polymerase chain reaction in a separate replication cohort of 39 subjects within the patient sample.

Results—

Our results showed that ACAS progression was associated with development of stroke. MiR-199b-3p, miR-27b-3p, miR-130a-3p, miR-221-3p, and miR-24-3p presented significant higher expression in those patients with ACAS progression.

Conclusions—

In conclusion, our study supports that specific circulating miRNA expression profiles could provide a new tool that complements the monitoring of ACAS progression, improving therapeutic approaches to prevent ischemic stroke.

[Immunohistochemical study of the role of mast cells and macrophages in the process of angiogenesis in the atherosclerotic plaques in patients with metabolic syndrome]

OBJECTIVE

to analyze the histotopographic distribution of neogenic vessels, the degree of mast cell degranulation, the expression of markers of macrophages in different types of plaques in different stages and in different arterial vessels in patients with atherosclerosis and in those with metabolic syndrome associated with atherosclerosis and to establish the role of mast cells and macrophages in the development of stages of atherosclerosis along with their diagnostic and prognostic value.

MATERIAL AND METHODS

Fragments of the thoracic and abdominal aorta, middle cerebral, carotid, renal, and iliac, and vertebral arteries from 34 persons who had died from atherosclerosis (n=17) and atherosclerotic complications due to metabolic syndrome (n=17) were examined. The investigators employed standard techniques, such as hematoxylin-eosin or orcein staining; silver impregnation. They used immunohistochemical staining with anti-mast cell tryptase (anti-MCT) for the determination of mast cells, the specific markers CD68 for macrophages, and CD105 (endoglin) for neogenic vessels.

RESULTS

The immunohistochemical technique is effective in identifying mast cells, macrophages, and neogenic vessels in atherosclerotic plaques. They were found in many types of atherosclerotic plaques, advantium, and subendothelial layers in the immediate vicinity of the plaques. There was a statistical correlation between the types of plaques and clinical data, which is of importance in elucidating the specific features of the pathogenesis of atherosclerosis in patients with metabolic syndrome.

CONCLUSION

CD105 is a sensitive marker for neogenic endothelial cells, an effective indicator of microvascular activation and proliferation in the atherosclerotic plaques. Neovascularization in the plaques frequently begins in the intima, progresses, and gives rise to their further destabilization. Anti-MCT staining used to reveal mast cells and CD68 for macrophages can elucidate the important patterns of development of atherosclerosis and its complications in patients with metabolic disturbances.

Cardiac Affection in Type 1 Diabetic Patients in Relation to Omentin

AIM:

To evaluate cardiac affection in type 1 diabetes in relation to Omentin.

PATIENTS AND METHODS:

Sixty two diabetics and 30 volunteer of the same age and sex were included as a control group. Blood sample was taken for assessment of omentin and oxidized low density lipoprotein (OxLDL), glycosylated hemoglobin (HbA1) and lipid profile. Urine sample was taken for assessment of albumin/creatinine ratio. 24 hour holter was also done. T-test, simple correlation followed by stepwise multiple regression analysis was used for analysis of data.

RESULTS:

Parameters of 24 hour holter were significantly lower in diabetics. Omentin was significantly lower, while OxLDL were significantly higher than controls. RMSSD, ST deviation and OxLDL were the parameters related to omentin by stepwise multiple regression analysis in diabetics.

CONCLUSION:

Diabetic patients had a cardiac autonomic neuropathy. A significant reduction of omentin and elevation OxLDL imply that they influence glucose metabolism in type 1 diabetes. Omentin had a significant relation to 24 hr holter which may reflect its role in cardiac affection. Omentin and OxLDL had a role in renal affection.

New Insights into the Role of Metformin Effects on Serum Omentin-1 Levels in Acute Myocardial Infarction: Cross-Sectional Study

Background. Serum omentin-1 level was low in the most types of ischemic heart disease compared to normal subjects; it also dependently correlated with coronary heart disease; thus, omentin-1 is regarded as a novel biomarker in IHD. Objective. The aim of the present study was to establish the links between omentin-1 and acute myocardial infarction in metformin patients. Subjects and Methods. A cross-sectional study was performed on eighty-five patients with type II DM and acute MI. They are divided as follows: Group I, 62 patients with type II DM who received metformin prior to onset of acute MI; Group II, 23 patients with type II DM who did not receive metformin prior to onset of acute MI; and Group III, 30 normal healthy controls. Venous blood was drawn from each participant for determination of lipid profile, plasma omentin-1, cardiac troponin-I (cTn-I) and other routine tests. Results. Patients that presented with acute MI that received metformin show a significant difference in all biochemical parameters (p < 0.001); metformin increases serum omentin-1 level and decreases serum cardiac troponin-I level compared with control subjects and nonmetformin treated patients. Conclusion. Metformin pharmacotherapy increases omentin-1 serum levels and may be regarded as a potential agent in the prevention of the occurrences of acute MI in diabetic patients.

The protective functions of omentin in cardiovascular diseases

Adipose tissue is considered as a large gland that can produce paracrine and endocrine hormones. Growing evidence suggests that adipocytes may link obesity to cardiovascular diseases (CVD). Adipose tissue produces a large number of mediators, which affect metabolism, inflammation and coagulation. Omentin, a novel adipocytokine, has come into the center of interest due to its favorable effects on inflammation, glucose homeostasis and CVD. The present review provides a concise and general overview on the roles of omentin in CVD. The knowledge of these concepts may provide a new strategy to reduce disease risks on CVD in the future.

Vulnerable plaques in the contralateral carotid arteries in symptomatic patients: a detailed ultrasound analysis

BACKGROUND AND AIM

Carotid plaques may represent a generalized atherosclerotic syndrome or a localized disease. The aim of this study was to assess the morphological and textural features of carotid plaques located contralateral to the symptomatic side and compare them with the symptomatic side and with plaques from asymptomatic patients.

METHODS

We studied 66 arteries in 39 patients (mean age 70 ± 7 year, 33% females). Arterial plaques were classified as either symptomatic (n = 30), contralateral to symptomatic (n = 25) or asymptomatic (n = 11). We compared several plaque features between these groups including the mean values of the grey scale median (GSM), entropy, juxtaluminal black area (JBA) without visible echogenic cap, GSM of the JBA and surface irregularity.

RESULTS

The plaques contralateral to symptomatic arteries had similar morphological and textural features to those in the symptomatic arteries. In contrast, they had more vulnerable morphological and textural features than those in asymptomatic arteries: less smooth plaques (12% vs. 55%) and instead more often mildly irregular (60% vs 36%) or markedly irregular (28% vs. 9%; p = 0.03), lower GSM (26.2 ± 8 vs. 49.4 ± 14, p < 0.001) and lower GSM of the JBA (5.0 ± 3.6 vs. 11.4 ± 2.1, p = 0.008). The frequency of entropy and plaque calcification was similar in all groups.

CONCLUSION

Symptomatic patients with carotid artery disease seem to have similar morphological and textural features of vulnerability in the symptomatic and the contralateral carotid arteries, which are profound compared with asymptomatic carotid arteries. These findings support the concept of generalized carotid atherosclerotic pathology rather than incidental unilateral disease, and also emphasize a need for aggressive measures for plaque stabilization, particularly in symptomatic patients.

Adhesion molecule CD146 and its soluble form correlate well with carotid atherosclerosis and plaque instability

AIMS

Intraplaque neovascularization and foam cell infiltration contribute to the development of unstable plaque, leading to thromboembolism and stroke. Cell adhesion molecules (CAMs) have been reported to be involved in the progression of atherosclerosis and plaque vulnerability. The aim of this study was to assess the association of adhesion molecule CD146 with carotid plaque instability.

METHODS

We collected forty atherosclerotic plaques from 40 patients undergoing carotid endarterectomy. The clinical information of each patient was obtained, and the plaque morphology and characteristics were examined by the ultrasound. The CD146 expressions of the plaques were graded by using semiquantitative scales. The serum level of soluble form of CD146 was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

CD146 expression was mainly on the intraplaque blood vessels and infiltrated macrophages. The CD146 expression was strongly correlated with the matrix metalloproteinase-9(MMP-9)expressions (P < 0.001) in the plaques. Soluble CD146 (sCD146) was also elevated in patients with atherosclerotic plaques. There was significant correlation between the increased CD146 expression and sCD146 level (P = 0.0057). sCD146 correlated well with serum MMP-9 (P < 0.0044), IL-6 (P = 0.0044) and high sensitivity C-reactive protein (hsCRP) (P = 0.005).

CONCLUSIONS

Adhesion molecules CD146 and its soluble form strongly correlated with the development of inflammation of atherosclerosis and plaque instability. CD146 may be a promising biomarker for monitoring the development and instability of atherosclerotic plaque in patients with carotid diseases.

Spontaneous echo contrast and thrombus formation at the carotid bifurcation after carotid endarterectomy

Spontaneous echo contrast (SEC) consists of numerous microechoes swirling in the cardiovascular lumen and is usually seen during blood stasis in dysfunctional left atrium. However, SEC and consecutive local thrombus formation at the carotid artery early after carotid endarterectomy (CEA) have not been reported. This study retrospectively investigated the clinical importance and therapeutic strategy of postoperative SEC and thrombus formation in 113 consecutive patients who underwent CEA between 2001 and 2009. Ultrasonography was routinely performed preoperatively, intraoperatively, and 1 day and 1 week after the operation. If SEC and/or thrombus was detected at any time after the operation, follow-up ultrasonography was performed at short intervals, once a week for inpatients and once every 1-2 months for outpatients. Eight of the 113 patients (7%) had SEC after the operation from Day 1 to 12 (mean 7.2 days), and 6 of these 8 patients developed local de novo thrombus formation at the site of SEC from Day 6 to 33 (mean 14.7 days). The maximum luminal narrowing by the thrombi were 26-62% (mean 37%). After administering anticoagulant therapy, all thrombi disappeared from Day 13 to 190 (mean 57 days) from CEA. SEC seen after CEA is highly associated with consecutive local thrombus formation. Postoperative geometric blood stasis with the absence of intima may be the causative factor for its development.

Synergistic effect of scavenger receptor A and low-density lipoprotein receptor on macrophage foam cell formation under inflammatory stress

To provide experimental evidence for the effect of inflammation on cholesterol accumulation in macrophages, we investigated the expression of low-density lipoprotein receptor (LDL-R) and scavenger receptor A (SR-A) genes and proteins in the lipopolysaccharide (LPS)-stimulated macrophage-like RAW264.7 cell line. RAW264.7 cells were incubated in serum-free medium in the absence or presence of LDL alone, LDL+LPS and LPS alone. Intracellular cholesterol content, tumor necrosis factor α levels in the supernatants, mRNA and protein expression of LDL-R and SR-A in the treated cells were assessed by Oil Red O staining cholesterol enzymatic assay, enzyme-linked immunosorbent assay, semi-quantitative polymerase chain reaction and western blot analysis, respectively. Our results demonstrated that LPS was able to upregulate SR-A mRNA and protein expression, override LDL-R suppression induced by a high dose of LDL and increase LDL uptake by enhancing receptor expression, leading to foam cell formation in RAW264.7 cells. These findings suggest that the synergy of the upregulation of SR-A and dysregulation of LDL-R under inflammatory stress may contribute to macrophage-derived foam cell formation.

First in vivo application of microwave radiometry in human carotids: a new noninvasive method for detection of local inflammatory activation

OBJECTIVES

This study investigated whether temperature differences: 1) can be measured in vivo noninvasively by microwave radiometry (MR); and 2) are associated with ultrasound and histological findings.

BACKGROUND

Studies of human carotid artery samples showed increased heat production. MR allows in vivo noninvasive measurement of internal temperature of tissues.

METHODS

Thirty-four patients undergoing carotid endarterectomy underwent screening of carotid atherosclerosis by ultrasound and MR. Healthy volunteers were enrolled as a control group. During ultrasound study, plaque texture, plaque surface, and plaque echogenicity were analyzed. Temperature difference (ΔT) was assigned as maximal minus minimum temperature. Association of thermographic with ultrasound and histological findings was performed.

RESULTS

ΔT was higher in atherosclerotic carotid arteries compared with the carotid arteries of controls (p < 0.01). Fatty plaques had higher ΔT compared with mixed and calcified (p < 0.01) plaques. Plaques with ulcerated surface had higher ΔT compared with plaques with irregular and regular surface (p < 0.01). Heterogeneous plaques had higher ΔT compared with homogenous (p < 0.01). Specimens with thin fibrous cap and intense expression of CD3, CD68, and vascular endothelial growth factor (VEGF) had higher ΔT compared with specimens with thick cap and low expression of CD3, CD68, and VEGF (p < 0.01).

CONCLUSIONS

MR provides in vivo noninvasive temperature measurements of carotid plaques, reflecting plaque inflammatory activation.

Noninvasive detection of neural progenitor cells in living brains by MRI

The presence of pericytes in brain regions undergoing repair is evident of the recruitment of bone marrow-derived multipotent regenerative cells to the neurovascular unit during angiogenesis. At present, post mortem sampling is the only way to identify them. Therefore, such cell typing is inadequate for preserving neural progenitor cells for any meaningful stem cell therapy. We aimed to target cerebral pericytes in vivo using dual gene transcript-targeted MRI (GT-tMRI) in male C57black6 mice after a 60-min bilateral carotid artery occlusion (BCAO). We attached superparamagnetic iron oxide nanoparticles (SPIONs) to phosphorothioate-modified micro-DNA that targets actin or nestin mRNA. Because BCAO compromises the blood-brain barrier (BBB) and induces expression of α-smooth muscle (αSM)-actin and nestin antigens by pericytes in new vessels, we delivered pericyte-specific magnetic resonance contrast agents (SPION-actin or SPION-nestin at 4 mg Fe/kg) by i.p. injection to C57black6 mice that had experienced BCAO. We demonstrated that the surge in cerebral iron content by inductively coupled plasma-mass spectrometry matched the increase in the frequency of relaxivity. We also found that SPION-nestin was colocalized in αSM- actin- and nestin-expressing pericytes in BCAO-treated C57black6 or transgenic mice [B6.Cg-Tg(CAG-mRFP1) 1F1Hadj/J, expressing red fluorescent protein by actin promoter]. We identified pericytes in the repair patch in living brains after BCAO with a voxel size of 0.03 mm(3). The presence of electron-dense nanoparticles in vascular pericytes in the region of BBB injury led us to draw the conclusion that GT-tMRI can noninvasively reveal neural progenitor cells during vascularization.

Lysophosphatidic acid effects on atherosclerosis and thrombosis

Lysophosphatidic acid (LPA) has been found to accumulate in high concentrations in atherosclerotic lesions. LPA is a bioactive phospholipid produced by activated platelets and formed during the oxidation of LDL. Accumulating evidence suggests that this lipid mediator may serve as an important risk factor for development of atherosclerosis and thrombosis. The role of LPA in atherogenesis is supported by the evidence that LPA: stimulates endothelial cells to produce adhesion molecules and chemoattractants; induces smooth muscle cells to produce inflammatory cytokines; stimulates smooth muscle cell dedifferentiation, proliferation, and migration; increases monocyte migration and decreases monocyte-derived cell emigration from the vessel wall; induces hypertension and vascular neointimal formation in vivo; and promotes plaque progression in a mouse atherosclerosis model. The role of LPA in thrombogenesis is supported by the evidence that LPA markedly induces the aggregation of platelets and the expression of tissue factor, which is the principal initiator of blood coagulation. Recent experimental data indicate that LPA is produced by specific enzymes and that LPA binds to and activates multiple G-protein-coupled receptors, leading to intracellular signaling. Therapeutics targeting LPA biosynthesis, metabolism and signaling pathways could be viable for prevention and treatment of atherosclerosis and thrombosis.

Impact of chronic kidney disease on carotid plaque vulnerability

OBJECTIVE

Little is known about the effect of chronic kidney disease (CKD) on plaque morphology in cerebral vessels. We therefore analyzed plaque composition and metabolic and chemical parameters with regard to clinical outcome in patients with advanced carotid artery stenosis (>70%) and normal or impaired renal function.

METHODS

Carotid endarterectomy plaques were collected from 114 patients, 51 with CKD and 63 without CKD (mean estimated glomerular filtration rate, 49 ± 9 vs 88 ± 14 mL/min), and analyzed by histology and immunohistochemistry. Serum levels of matrix metalloproteinases (MMP-1, -2, -3, -7, -8, and -9), calcium, phosphate, parathyroid hormone, fetuin-A, osteoprotegerin, and inflammatory factors, including fibrinogen, and high-sensitive C-reactive protein (hsCRP) were measured by appropriate enzyme-linked immunosorbent assay.

RESULTS

Compared with patients without CKD, patients with CKD had significantly more early-stage (11.2% vs 2.8%, P = .002) and end-stage (7.4% vs 0.2%, P = .036) calcification, unstable (50.8% vs 20.4%, P = .001) and ruptured (53.1% vs 32.8%, P = .035) lesions, and a significantly lower amount of collagenous fibers (39.2% vs 54.6%, P = .001). Serum samples of CKD patients had significantly enhanced levels of fibrinogen (393 ± 88 vs 331 ± 60 mg/dL, P = .018), hsCRP (1.7 ± 2.9 vs 0.8 ± 0.9 mg/dL; P = .042), parathyroid hormone (47.3 ± 24.1 vs 32.8 ± 12.2 ng/L, P = .010), fetuin-A (0.21 ± 0.05 vs 0.18 ± 0.04 mg/mL, P = .039), and MMP-7 (13.0 ± 5.3 vs 8.3 ± 3.0 ng/mL; P < 0.001). The incidence of cerebrovascular events >6 months before carotid surgery was significantly increased in CKD patients (84.0% vs 26.2% P < .001).

CONCLUSIONS

In patients with CKD and advanced carotid artery stenosis, morphologic changes in plaque composition may contribute to plaque vulnerability and consequently to the risk of cerebrovascular events. Furthermore, relevant serum markers of inflammation, vascular calcification, and vessel wall degradation might be an indication of stroke risk in CKD patients.

Metformin treatment may increase omentin-1 levels in women with polycystic ovary syndrome

OBJECTIVE

Polycystic ovary syndrome (PCOS) is associated with the metabolic syndrome. Decreased omentin-1 levels are associated with obesity and diabetes. To study the effects of metformin treatment on omentin-1 levels in PCOS subjects and effects of omentin-1 on in vitro migration and angiogenesis.

RESEARCH DESIGN AND METHODS

Serum omentin-1 was measured by ELISA. Angiogenesis was assessed by studying capillary tube formation in human microvascular endothelial cells (HMEC-1) on growth factor reduced Matrigel. Endothelial cell migration assay was performed in a modified Boyden chamber. Nuclear factor-κB (NF-κB) was studied by stably transfecting HMEC-1 cells with a cis-reporter plasmid containing luciferase reporter gene linked to five repeats of NF-κB binding sites. Akt phosphorylation was assessed by Western blotting.

RESULTS

Serum omentin-1 was significantly lower in PCOS women (P < 0.05). After 6 months of metformin treatment, there was a significant increase in serum omentin-1 (P < 0.01). Importantly, changes in hs-CRP were significantly negatively correlated with changes in serum omentin-1 (P = 0.036). In vitro migration and angiogenesis were significantly increased in serum from PCOS women (P < 0.01) compared with matched control subjects; these effects were significantly attenuated by metformin treatment (P < 0.01) plausibly through the regulation of omentin-1 levels via NF-κB and Akt pathways. CRP and VEGF induced in vitro migration, and angiogenesis was significantly decreased by omentin-1.

CONCLUSIONS

Increases in omentin-1 levels may play a role but are not sufficient to explain the decreased inflammatory and angiogenic effects of sera from metformin-treated PCOS women.

Increased serum kallistatin levels in type 1 diabetes patients with vascular complications

BACKGROUND

Kallistatin, a serpin widely produced throughout the body, has vasodilatory, anti-angiogenic, anti-oxidant, and anti-inflammatory effects. Effects of diabetes and its vascular complications on serum kallistatin levels are unknown.

METHODS

Serum kallistatin was quantified by ELISA in a cross-sectional study of 116 Type 1 diabetic patients (including 50 with and 66 without complications) and 29 non-diabetic controls, and related to clinical status and measures of oxidative stress and inflammation.

RESULTS

Kallistatin levels (mean(SD)) were increased in diabetic vs. control subjects (12.6(4.2) vs. 10.3(2.8) μg/ml, p = 0.007), and differed between diabetic patients with complications (13.4(4.9) μg/ml), complication-free patients (12.1(3.7) μg/ml), and controls; ANOVA, p = 0.007. Levels were higher in diabetic patients with complications vs. controls, p = 0.01, but did not differ between complication-free diabetic patients and controls, p > 0.05. On univariate analyses, in diabetes, kallistatin correlated with renal dysfunction (cystatin C, r = 0.28, p = 0.004; urinary albumin/creatinine, r = 0.34, p = 0.001; serum creatinine, r = 0.23, p = 0.01; serum urea, r = 0.33, p = 0.001; GFR, r = -0.25, p = 0.009), total cholesterol (r = 0.28, p = 0.004); LDL-cholesterol (r = 0.21, p = 0.03); gamma-glutamyltransferase (GGT) (r = 0.27, p = 0.04), and small artery elasticity, r = -0.23, p = 0.02, but not with HbA1c, other lipids, oxidative stress or inflammation. In diabetes, geometric mean (95%CI) kallistatin levels adjusted for covariates, including renal dysfunction, were higher in those with vs. without hypertension (13.6 (12.3-14.9) vs. 11.8 (10.5-13.0) μg/ml, p = 0.03). Statistically independent determinants of kallistatin levels in diabetes were age, serum urea, total cholesterol, SAE and GGT, adjusted r2 = 0.24, p < 0.00001.

CONCLUSIONS

Serum kallistatin levels are increased in Type 1 diabetic patients with microvascular complications and with hypertension, and correlate with renal and vascular dysfunction.

An update on markers of carotid atherosclerosis in patients with Type 2 diabetes

Carotid atherosclerosis constitutes an important cause of ischemic brain attack and stroke, accounting for up to 40% of cases of ischemic cerebrovascular disease. Type 2 diabetes mellitus is an independent risk factor for stroke and its recurrence. Thus, identifying diabetic patients who are at high risk of developing stroke is of great clinical importance. Noninvasive measurements of surrogate markers of atherosclerosis, such as novel serum biomarkers, can be helpful in detecting subclinical carotid disease, especially among individuals at the highest cardio-/cerebro-vascular risk. Previous studies have proposed an expanding body of serum biomarkers, such as C-reactive protein, fibrinogen, adipokines, cytokines and growth factors, as novel indicators of carotid atherosclerosis development that predict carotid-related clinical outcomes. Furthermore, those biomarkers are expected to assess the efficacy of both pharmaceutical and interventional strategies. Accordingly, it is increasingly clear that measuring biomarkers may improve the definition of cerebrovascular risk profile in patients with Type 2 diabetes mellitus.

CD105 positive neovessels are prevalent in early stage carotid lesions, and correlate with the grade in more advanced carotid and coronary plaques

Background

Previous studies have demonstrated that expression of CD105 is a sensitive marker and indicator of endothelial cell/microvessel activation and proliferation in aggressive solid tumour growth and atherosclerotic plaque lesions. Since intimal neovascularization contributes significantly to subsequent plaque instability, haemorrhage and rupture.

Methods

We have used immunohistochemical analysis to investigate the expression of CD105-positive vessels in both large (carotid) and medium calibre (coronary and middle cerebral artery, MCAs) diseased vessels in an attempt to identify any correlation with plaque growth, stage and complication/type.

Results

Here we show, that carotid arteries expressed intimal neovascularization associated with CD105-positive endothelial cells, concomitant with increased inflammation in early stage lesions, preatheroma (I-III) whilst they were not present in coronary plaques of the same grade. Some of these CD105-positive neovessels were immature, thin walled and without smooth muscle cell coverage making them more prone to haemorrhage and rupture. In high-grade lesions, neovessel proliferation was similar in both arterial types and significantly higher numbers of CD105-positive vasa vasorum were associated with plaque regions in coronary arteries. In contrast, although the MCAs exhibited expanded intimas and established plaques, there were very few CD105 positive neovessels.

Conclusion

Our results show that CD105 is a useful marker of angiogenesis within adventitial and intimal vessels and suggest the existence of significant differences in the pathological development of atherosclerosis in separate vascular beds which may have important consequences when considering management and treatment of this disease.

Metformin decreases angiogenesis via NF-kappaB and Erk1/2/Erk5 pathways by increasing the antiangiogenic thrombospondin-1

AIMS

Polycystic ovary syndrome (PCOS) is associated with insulin resistance (IR), obesity, and cardiovascular complications. Thrombospondin-1 (TSP-1) is a novel antiangiogenic adipokine highly expressed in obese insulin-resistant subjects. We sought to assess TSP-1 levels in adipose tissue (AT) from PCOS women and matched controls. The effects of metformin treatment on circulating TSP-1 levels in PCOS subjects, the effects of serum from normal and PCOS women on in vitro migration and angiogenesis before and after metformin treatment, and ex vivo regulation of AT TSP-1 by D-glucose were also studied.

METHODS AND RESULTS

Serum TSP-1 (ELISA), subcutaneous and omental AT TSP-1 mRNA (reverse transcriptase-polymerase chain reaction), and protein (western blotting) were significantly lower in PCOS women (P < 0.05). Corresponding plasminogen activator inhibitor-1 (PAI-1) and PAI-1 activity were significantly higher (P < 0.01). After 6 months of metformin treatment, there was a significant increase in serum TSP-1 (P < 0.05) and a corresponding decrease in PAI-1 and PAI-1 activity (P < 0.01). In vitro migration and angiogenesis were significantly increased in serum from PCOS women (P < 0.01); these effects were significantly attenuated by metformin treatment (P < 0.01) through the regulation of TSP-1 levels via nuclear factor-kappaB (NF-kappaB), extracellular regulated-signal kinase 1/2 (Erk1/2) and Erk5 pathways. Importantly, changes in the intima media thickness were predictive of changes in serum TSP-1 (P = 0.049). In AT explants, glucose significantly decreased TSP-1 protein production and secretion into conditioned media (ELISA) (P < 0.05, P < 0.001).

CONCLUSION

TSP-1 levels are lower in PCOS women. Metformin treatment increases serum TSP-1 in these women. Our findings provide novel insights into the relationship between obesity, IR, and angiogenesis.

Oxidized LDL and C-reactive protein level in relation to carotid intima-media thickness in population with risk factors for atherosclerosis

Introduction. Elevated levels of oxidized LDL cholesterol (OxLDL) are considered to be a key factor of initiating and accelerating atherosclerosis. It promotes atherosclerosis through inflammatory and immunologic mechanisms that lead to the formation of macrophage foam cells. Objective. To determine the relationship among OxLDL, C-reactive protein (CRP) level and carotid intima-media thickness (IMT) in population with risk factors for atherosclerosis. Methods. The study group consisted of 125 clinically healthy, hypercholesterolaemic subjects (49.3?5.7 years; 75 females and 50 males) compared with 100 age-matched population-based control subjects. The study group was divided into two subgroups: subgroup A (the levels of LDL cholesterol > 5 mmol/L) and subgroup B (the levels of LDL cholesterol <5 mmol/L). None of the subjects had history of cerebrovascular, ischaemic heart disease, hypertension or diabetes mellitus. Lipid profiles were measured by enzymatic methods. OxLDL was measured by using a specific monoclonal antibody, mAb4E6. CRP was measured using hemiluminescent methods (Immulite - DPC). The common carotid IMT was measured by the B-mode ultrasound. Results Compared to controls, the study group had higher levels of OxLDL (119.97?43.15 vs. 82.03?25.99 IU/L; p<0.01) and CRP (6.20?3.55 vs. 2.68?3.04 mg/ml; p<0.05). IMT was significantly higher in study subjects (1.14?0.38 vs. 0.72?0.24 mm; p<0.05). We also found that, in the whole study group, IMT significantly positively correlated with OxLDL (r=0.442; p<0.05). We found that in the study subgroup A, IMT positively correlated with CRP (r=0.792; p<0.01). In controls, we found a significantly positive association between IMT and OxLDL (r=0.781; p<0.01) and CRP (r=0.748; p<0.01). Conclusion. The elevated levels of OxLDL and CRP are associated with higher common carotid intima-media thickness in population with risk factors for atherosclerosis.