Plasma chemokine levels are associated with the presence and extent of angiographic coronary collaterals in chronic ischemic heart disease

Mechanistic role of CXCL5 in cardiovascular disease, diabetes mellitus, and kidney disease

Chemokines, by modulating inflammation process, could contribute to the development of cardiovascular disease, diabetes mellitus (DM), and kidney disease. Chemokine CXC motif ligand 5 (CXCL5) is one of the inducible chemokines that may be involved in various inflammatory diseases. Given the bidirectional promiscuity characteristics of the chemokine system, the mechanistic roles of CXCL5 should be further explored in each specific disease. In this article, we sought to review the recent evidence on the differential effects of CXCL5 and their potential mechanisms in cardiovascular disease, DM, and renal disease individually. Future study is still required to verify if CXCL5 could be a novel therapeutic target in these diseases.

Could Plasma CXCL12 Predict Ventricular Dysfunction in Patients with Severe Myocardial Infarction?

Plasma level of chemokine CXCL12 can predict adverse cardiovascular outcomes in patients with coronary artery disease, but data on its relationship with severity of coronary stenosis in cases of severe myocardial infarction (MI) are scarce and conflicting. The objective of this study was to investigate link between plasma CXCL12 levels and different grades of left ventricular ejection fraction (LVEF) in statin-treated and -untreated patients with severe MI. A total of 198 consecutive patients with first-time severe MI (ST-elevated myocardial infarction [STEMI], n  = 121 and non-ST-elevated myocardial infarction [NSTEMI], n  = 77) were recruited from Coronary Care Unit, King Abdulaziz University Hospital. They have one to two coronary arteries blocked ≥50%, or three arteries blocked 30 to 49%. Demographic and clinical criteria were collected and plasma CXCL12 level was measured. No correlations were detected between demographic and clinical criteria and CXCL12 level. While troponin peaks and LVEF significantly differed between STEMI and NSTEMI patients, CXCL12 level showed nonsignificant changes. Plasma CXCL12 levels decreased significantly in statin-treated patients compared with those untreated. From receiver operating characteristic (ROC) analysis, high CXCL12 levels were associated with no statin therapy. For STEMI and NSTEMI patients, area under the receiver operating characteristic curve for CXCL12 test were 0.685 and 0.820, while sensitivity and specificity values were 75.9 and 54.8%, and 73.1 and 84%, respectively. Plasma CXCL12 levels showed nonsignificant changes with different ranges of LVEF and troponin peaks. In patients with severe MI, irrespective of statin therapy, plasma CXCL12 showed no correlation with different ranges of LVEF suggesting that it cannot predict left ventricular dysfunction in these cases. However, cross-sectional design of this study is a limitation.

The Potential Importance of CXCL1 in the Physiological State and in Noncancer Diseases of the Cardiovascular System, Respiratory System and Skin

In this paper, we present a literature review of the role of CXC motif chemokine ligand 1 (CXCL1) in physiology, and in selected major non-cancer diseases of the cardiovascular system, respiratory system and skin. CXCL1, a cytokine belonging to the CXC sub-family of chemokines with CXC motif chemokine receptor 2 (CXCR2) as its main receptor, causes the migration and infiltration of neutrophils to the sites of high expression. This implicates CXCL1 in many adverse conditions associated with inflammation and the accumulation of neutrophils. The aim of this study was to describe the significance of CXCL1 in selected diseases of the cardiovascular system (atherosclerosis, atrial fibrillation, chronic ischemic heart disease, hypertension, sepsis including sepsis-associated encephalopathy and sepsis-associated acute kidney injury), the respiratory system (asthma, chronic obstructive pulmonary disease (COPD), chronic rhinosinusitis, coronavirus disease 2019 (COVID-19), influenza, lung transplantation and ischemic-reperfusion injury and tuberculosis) and the skin (wound healing, psoriasis, sunburn and xeroderma pigmentosum). Additionally, the significance of CXCL1 is described in vascular physiology, such as the effects of CXCL1 on angiogenesis and arteriogenesis.

CXCL5 gene polymorphisms and coronary collateralization

Background

The presence of coronary collateralization is heterogenous, even amongst those with similar degrees of epicardial coronary artery stenoses. We hypothesized that genetic variation of CXCL5, a chemokine that mediates angiogenesis, is associated with coronary collateralization.

Methods

We genotyped subjects undergoing coronary angiography for single nucleotide polymorphisms of CXCL5 and determined the presence of spontaneously visible coronary collaterals.

Results

Subjects with collaterals had less angina (46 % vs 59 %, p = 0.006), and prior percutaneous coronary intervention (34 % vs 47 %, p = 0.010), and more hyperlipidemia (90 % vs 82 %, p = 0.018), peripheral arterial disease (25 % vs 17 %, p = 0.041), congestive heart failure (16 % vs 8 %, p = 0.007), and multi-vessel coronary artery disease (41 % vs 24 %, p = 0.0001) compared to those without collaterals. Multi-vessel disease and hyperlipidemia were positive predictors of angiographically visible collaterals while being a carrier of the CXCL5 polymorphism was a negative predictor.

Conclusions

Coronary collateralization may, at least in part, be genetically determined.

CXCL5: A coachman to drive cancer progression

Chemokines are a class of pro-inflammatory cytokines that can recruit and activate chemotactic cells. C‐X‐C motif chemokine ligand 5 (CXCL5) is a member of the chemokine family binding CXCR2 (C-X-C Motif Chemokine Receptor 2), a G-protein coupled receptor. Accumulated evidence has shown that dysregulated CXCL5 participates in tumor metastasis and angiogenesis in human malignant tumors. In this review, we summarized the advances in research on CXCL5, including its dysregulation in different tumors and the mechanism associated with tumor behavior (formation of the immunosuppressive microenvironment, promotion of tumor angiogenesis, and metastasis). We also summarized and discussed the perspective about the potential application of CXCL5 in tumor therapy targeting the tumor inflammatory microenvironment.

The Involvement of CXC Motif Chemokine Ligand 10 (CXCL10) and Its Related Chemokines in the Pathogenesis of Coronary Artery Disease and in the COVID-19 Vaccination: A Narrative Review

Coronary artery disease (CAD) and coronary heart disease (CHD) constitute two of the leading causes of death in Europe, USA and the rest of the world. According to the latest reports of the Iranian National Health Ministry, CAD is the main cause of death in Iranian patients with an age over 35 years despite a significant reduction in mortality due to early interventional treatments in the context of an acute coronary syndrome (ACS). Inflammation plays a fundamental role in coronary atherogenesis, atherosclerotic plaque formation, acute coronary thrombosis and CAD establishment. Chemokines are well-recognized mediators of inflammation involved in several bio-functions such as leucocyte migration in response to inflammatory signals and oxidative vascular injury. Different chemokines serve as chemo-attractants for a wide variety of cell types including immune cells. CXC motif chemokine ligand 10 (CXCL10), also known as interferon gamma-induced protein 10 (IP-10/CXLC10), is a chemokine with inflammatory features whereas CXC chemokine receptor 3 (CXCR3) serves as a shared receptor for CXCL9, 10 and 11. These chemokines mediate immune responses through the activation and recruitment of leukocytes, eosinophils, monocytes and natural killer (NK) cells. CXCL10, interleukin (IL-15) and interferon (IFN-g) are increased after a COVID-19 vaccination with a BNT162b2 mRNA (Pfizer/BioNTech) vaccine and are enriched by tumor necrosis factor alpha (TNF-α) and IL-6 after the second vaccination. The aim of the present study is the presentation of the elucidation of the crucial role of CXCL10 in the patho-physiology and pathogenesis of CAD and in identifying markers associated with the vaccination resulting in antibody development.

Association of chemokines IP-10/CXCL10 and I-TAC/CXCL11 with insulin resistance and enhance leukocyte endothelial arrest in obesity

BACKGROUND AND AIMS

Obesity is a key contributing factor to incidental type 2 diabetes and cardiovascular disease. CXCR3 receptor and its ligands CXCL 10 and 11 are associated with atherosclerosis and cardiovascular disease. The aim of our study was to analyse the role of the CXCR3 ligands on insulin resistance (IR) and endothelial dysfunction in human obesity.

METHODS AND RESULTS

We have studied 45 obese patients (mean age 44 ± 6 years, body mass index 45 ± 9 kg/m²) who were selected for Roux-Y-gastric bypass surgery and 21 non obese control subjects with similar age and gender distribution. We measured by ELISA the circulating levels of the CXCR3 ligands interferon-γ inducible protein 10 (IP-10/CXCL10) and interferon-γ-inducible T-cell alpha chemoattractant (I-TAC/CXCL11). Using an ex vivo procedure with the flow chamber assay, we have investigated the effect of such chemokines on endothelial leukocytes arrest under dynamic conditions. Peripheral blood levels of CXCL10 and CXCL11 were significantly higher in obese subjects than in controls (p < 0.001) and significantly correlated with BMI, waist circunference and HOMA-IR. Obese patients with HOMA-IR index above 75th percentile showed highest increase of circulating CXCL10 and CXCL11 values. Under dynamic flow conditions, the enhanced adhesion of patient leukocytes to TNFα-induced human arterial endothelial cells was partly dependent on CXCR3.

CONCLUSIONS

The study demonstrates that CXCL10 and CXCL11 are associated with IR and enhance leukocyte endothelial arrest in obese subjects. Blockade of CXCR3 signaling might be a new therapeutic approach for the prevention of obesity-associated cardiovascular co-morbidities.

Non-high-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio serve as a predictor for coronary collateral circulation in chronic total occlusive patients

Objective

The present study investigated the potential correlation between non-high-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (non-HDL-C/HDL) and the formation of coronary collateral circulation (CCC) in coronary artery disease cases with chronic total occlusive (CTO) lesions.

Methods

Two experienced cardiologists identified and selected patients with CTO lesions for retrospective analysis. The 353 patients were divided into a CCC poor formation group (Rentrop 0–1 grade, n = 209) and a CCC good formation group (Rentrop 2–3 grade, n = 144) based on the Cohen-Rentrop standard. A comparison of non-HDL-C/HDL ratios between the two groups was performed. The Spearman test was used to obtain the correlation between the cholesterol ratio and Rentrop grade. Independent predictors of CCC were analyzed using logistic regression. Receiver operating characteristic (ROC) curve analysis was also performed to quantify the predictive value of research indicator.

Results

The non-HDL-C/HDL ratio in the CCC poor formation group was elevated markedly compared to the CCC good formation group [( 3.86 ± 1.40) vs ( 3.31 ± 1.22), P = 0.000]. The Spearman test results indicated that non-HDL-C/HDL negatively correlated with Rentrop grade (r = − 0.115, P = 0.030). Multivariate logistic regression analysis showed that non-HDL-C/HDL ratio was an independent predictor of CCC formation (OR = 1.195, 95%CI = 1.020–1.400, P = 0.027). The area under the curve of ROC for detecting CCC poor formation was 0.611 (95% CI: 0.551–0.671, P = 0.000) with an optimal cut-off value of 2.77.

Conclusion

Non-HDL-C/HDL negatively correlated with the formation of CCC and served as an independent predictor of CCC formation, which may be used as a biomarker for the evaluation of CCC.

A Review of CXCL1 in Cardiac Fibrosis

Chemokine C-X-C motif ligand-1 (CXCL1), principally expressed in neutrophils, macrophages and epithelial cells, is a valid pro-inflammatory factor which performs an important role in mediating the infiltration of neutrophils and monocytes/macrophages. Elevated serum level of CXCL1 is considered a pro-inflammatory reaction by the organism. CXCL1 is also related to diverse organs fibrosis according to relevant studies. A growing body of evidence suggests that CXCL1 promotes the process of cardiac remodeling and fibrosis. Here, we review structure and physiological functions of CXCL1 and recent progress on the effects and mechanisms of CXCL1 in cardiac fibrosis. In addition, we explore the role of CXCL1 in the fibrosis of other organs. Besides, we probe the possibility that CXCL1 can be a therapeutic target for the treatment of cardiac fibrosis in cardiovascular diseases.

Higher serum level of Cystatin C: An additional risk factor of CAD

Cystatin C has been proposed as a useful biomarker of early impaired kidney function and a predictor of mortality risk. The present study is to investigate the association between serum Cystatin C and the severity of coronary artery lesions, Gensini score (GS), and the risk of coronary artery disease (CAD).A total of 682 CAD patients (230 females, 452 males; mean age 62.6 ± 10.7 years, range from 31 to 86 years) and 135 controls (41 females, 94 males; mean age 58.0 ± 10.3 years, range from 38 to 84 years) were recruited in the present study. Enzyme-linked immunosorbent assay was applied to measure serum cystatin C levels and other serum indexes. The estimated glomerular filtration rate and GS were calculated.Serum low-density lipoprotein cholesterol (LDL-C), uric acid, Cystatin C, and homocysteine (HCY) were significantly elevated in CAD patients compared to controls. There were significant differences regarding total cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, cystatin C, eGFR and GS among stable angina pectoris (SAP), unstable angina group (UAP), and acute myocardial infarction (AMI) patients. AMI group had an elevated serum Cystatin C, LDL-C, HCY, and GS than SAP and UAP patients. When stratified patient groups by the quartiles of Cystatin C, we found age, the proportion of male and patients with diabetes, HCY, and GS were increased in Q4 than in other quartile groups. Spearman correlation test revealed a positive relationship between Cystatin C, HCY, and GS. Multivariate logistic regression analysis revealed that serum Cystatin C level, presence of hypertension and diabetes, HCY, age, and male were the risk factors for coronary artery lesions.In summary, our results suggested that cystatin C is a promising clinical biomarker that provides complementary information to the established risk determinants. The serum Cystatin C level is strongly associated with GS and could be used to evaluate the severity of coronary artery lesions.

Adipose tissue gene expression of CXCL10 and CXCL11 modulates inflammatory markers in obesity: implications for metabolic inflammation and insulin resistance

BACKGROUND

The CXCL subfamily of chemokines (CXCL9, CXCL10, and CXCL11; angiostatic chemokines) plays a key role in many inflammatory diseases. However, the expression of CXCLs in adipose tissue (AT) during obesity and association of these CXCLs with inflammatory markers and insulin resistance are poorly understood. Therefore, this study aimed to investigate the effects of CXCL gene expression on subcutaneous AT inflammatory markers and insulin resistance.

METHODS

Subcutaneous-fat biopsies were collected from 59 nondiabetic (lean/overweight/obese) individuals for RNA isolation. Expression levels of AT CXCL and inflammatory markers were determined by quantitative reverse transcriptase polymerase chain reaction (RT-qPCR). Biomedical parameters in the plasma were measured by enzyme-linked immunosorbent assay (ELISA). Insulin resistance was estimated using homeostatic model assessment (HOMA-IR).

RESULTS

AT CXCL expression was higher in obese compared with lean individuals (p < 0.05) and positively correlated with body mass index (BMI; r ⩾ 0.269, p < 0.05). Expression of CXCL9, CXCL10, and CXCL11 correlated significantly with various pro-inflammatory markers, including family members of interleukins, chemokines, and their prospective receptors (r ⩾ 0.339, p ⩽ 0.009), but not anti-inflammatory markers. CXCL11 expression correlated specifically with the expression of CCL5, CCL18, TLR3, TLR4, TLR8, IRF5, and NF-κB (r ⩾ 0.279, p ⩽ 0.039). Notably, CXCL11 was correlated with C-reactive protein (CRP), fasting blood glucose (FBG), and HOMA-IR. In multiple regression analysis, CXCL11 was identified as an independent predictor of CCL19, CCL5, IL-6, and TLR3.

CONCLUSION

These data suggest that the CXCL family members, specifically CXCL10 and CXCL11, are potential biomarkers for the onset of AT inflammation during obesity.

Serum concentration of angiogenic (CXCL1, CXCL12) and angiostasis (CXCL9, CXCL10) CXC chemokines are differentially altered in normal and gestational diabetes mellitus associated pregnancies

BACKGROUND

The present study was aimed and designed to determine the serum levels of CXCL1 and CXCL12 as angiogenesis along with CXCL9 and CXCL10 as angiostasis, chemokines in, Gestational diabetes mellitus mothers (GDMM) and normal pregnancy mothers (NPM) and neonates who delivered by them.

METHODS

We have recruited 63 pregnant GDMM and 63 normal pregnant mothers at the third trimester of pregnancy to this cross-sectional study. Cord blood specimens were obtained from neonates who were delivered from GDMM and NPM. The serum and cord blood levels of chemokines were measured by ELISA in studied groups. Data were analyzed by chi-square and student's t test between two groups. The P-values less than 0.05 were considered significant.

RESULTS

Our results revealed that the serum levels of CXCL1, CXCL9 and CXCL12 were increased in GDMM, while no alteration was found in the serum levels of CXCL10 when compared to NPM. We have observed that in neonates the serum levels of angiogeneic chemokines followed an inverse fashion when compared to angiostasis chemokines. Interestingly, CXCL1 and CXCL12 were both increased in neonates who were delivered by GDMM, while, CXCL9 and CXCL10 were decreased in neonates delivered by GDMM.

Potential Effects of CXCL9 and CCL20 on Cardiac Fibrosis in Patients with Myocardial Infarction and Isoproterenol-Treated Rats

The chemokines CXCL9 and CCL20 have been reported to be associated with ventricular dysfunction. This study was aimed to investigate the effects of CXCL9/CCL20 on cardiac fibrosis following myocardial infarction (MI). Blood samples of patients with MI were obtained to determine the serum CXCL9, CCL20, tumor necrosis factor-α (TNF-α), and transforming growth factor-β (TGF-β). The expression of CXCL9 and CCL20 in hypoxia-incubated H9c2 cells and TNF-α/TGF-β-activated peripheral blood mononuclear cells (PBMCs) were examined. The experimental MI of rats was produced by the intraperitoneal injection of isoproterenol (ISO) (85 mg/kg/day) for two consecutive days. The growth and migration of CXCL9/CCL20-incubated cardiac fibroblasts in vitro were evaluated. TNF-α/TGF-β-activated PBMCs showed an enhanced expression of CXCL9 and CCL20, while hypoxic H9c2 cells did not. Patients with MI had significantly enhanced levels of serum TGF-β and CXCL9 compared to healthy subjects. ISO-treated rats had increased serum CXCL9 levels and marked cardiac fibrosis compared to control rats. The trend of increased serum CCL20 in patients with MI and ISO-treated rats was not significant. CXCL9-incubated cardiac fibroblasts showed enhanced proliferation and migration. The findings of this study suggest that an enhanced expression of CXCL9 following MI might play a role in post-MI cardiac fibrosis by activating cardiac fibroblasts.

The Role of CXCR3 and Associated Chemokines in the Development of Atherosclerosis and During Myocardial Infarction

The chemokine receptor CXCR3 and associated CXC chemokines have been extensively investigated in several inflammatory and autoimmune diseases as well as in tumor development. Recent studies have indicated the role of these chemokines also in cardiovascular diseases. We aimed to present current knowledge regarding the role of CXCR3-binding chemokines in the pathogenesis of atherosclerosis and during acute myocardial infarction.

Association between circulating fibrocytes and angiographic coronary collaterals in patients with obstructive coronary artery disease

Circulating fibrocytes are a population of bone marrow-derived progenitor cells that have been implicated in neovascularization. The recruitment of coronary artery collaterals, a form of neovascularization, is associated with improved outcomes in coronary artery disease. In this study, we tested the hypothesis that, in subjects with stable chronic coronary artery disease, the blood concentration of fibrocytes is associated with the presence of angiographic coronary collaterals. A total of 58 subjects with at least one epicardial coronary artery with ≥ 90% luminal stenosis were enrolled, among whom 26 (45%) had angiographic evidence of coronary collaterals. Subjects with collaterals had significantly elevated circulating concentrations of all examined subsets of activated fibrocytes, suggesting that there is a relationship between fibrocytes and coronary collateral recruitment.

Upregulation of angiostatic chemokines IP-10/CXCL10 and I-TAC/CXCL11 in human obesity and their implication for adipose tissue angiogenesis

BACKGROUND/AIMS

Impaired angiogenesis is linked to adipose tissue (AT) dysfunction, inflammation, and insulin resistance in human obesity. Chemokine (C-X-C motif) receptor. (CXCR3) ligands are important regulators of angiogenesis in different disease contexts such as cancer; however, their role in human morbid obesity is unknown. We investigated the role of the CXCR3 axis in AT angiogenesis in morbidly obese patients.

SUBJECTS/METHODS

The study group comprised 50 morbidly obese patients (mean age 44 ± 1 years, body mass index 44 ± 1 kg/m²) who had undergone laparoscopic Roux-Y-gastric bypass surgery, and 25 age-matched non-obese control subjects. We measured the circulating levels of the CXCR3 ligands monokine induced by interferon-γ (MIG/CXCL9), interferon-γ inducible protein 10 (IP-10/CXCL10), and interferon-γ-inducible T-cell alpha chemoattractant (I-TAC/CXCL11) in all studied subjects. Additionally, the expression of CXCR3 ligands was analyzed in paired biopsies of subcutaneous and visceral AT obtained during the laparoscopic procedure in morbidly obese patients. Additionally, we explored the functional role of CXCR3 ligands on angiogenesis in AT from morbidly obese patients using an ex vivo assay.

RESULTS

Plasma levels of CXCL10 and CXCL11 were significantly higher in morbidly obese patients than in controls (p < 0.01). In ex vivo assays, angiogenic growth was markedly lower in visceral AT than in subcutaneous AT (p < 0.05), which was related to significant tissue upregulation of CXCL10, CXCL11 and CXCR3 (p < 0.05). CXCL10 or CXCL11 inhibited AT angiogenesis (p < 0.05), and blockade of CXCR3 function significantly increased capillary sprouting in visceral fat deposits (p < 0.05). Western blot analysis showed that the p38 mitogen-activated protein kinase signaling pathway was implicated in the angiostatic effects of CXCR3 in AT.

CONCLUSIONS

CXCL10 and CXCL11 may play. deleterious role in obesity as potential inhibitors of AT angiogenesis. Accordingly, pharmacological blockade of CXCR3 could represent. therapy to prevent AT dysfunction in obesity.

Reduced coronary collateralization in type 2 diabetic patients with chronic total occlusion

BACKGROUND

The extent of coronary collateral formation is a primary determinant of the severity of myocardial damage and mortality after coronary artery occlusion. Type 2 diabetes mellitus (T2DM) represents an important risk factor for impaired collateral vessel growth. However, the mechanism of reduced coronary collateralization in type 2 diabetic patients remains unclear.

METHODS

With the reference to the recent researches, this review article describes the pathogenic effects of T2DM on collateral development and outlines possible clinical and biochemical markers associated with reduced coronary collateralization in type 2 diabetic patients with chronic total occlusion (CTO).

RESULTS

Diffuse coronary atherosclerosis in T2DM reduces pressure gradient between collateral donor artery and collateral recipient one, limiting collateral vessel growth and function. An interaction between advanced glycation end-products and their receptor activates several intracellular signaling pathways, enhances oxidative stress and aggravates inflammatory process. Diabetic condition decreases pro-angiogenic factors especially vascular endothelial growth factor and other collateral vessel growth related parameters. Numerous clinical and biochemical factors that could possibly attenuate the development of coronary collaterals have been reported. Increased serum levels of glycated albumin, cystatin C, and adipokine C1q tumor necrosis factor related protein 1 were associated with poor coronary collateralization in type 2 diabetic patients with stable coronary artery disease and CTO. Diastolic blood pressure and stenosis severity of the predominant collateral donor artery also play a role in coronary collateral formation.

CONCLUSIONS

T2DM impairs collateral vessel growth through multiple mechanisms involving arteriogenesis and angiogenesis, and coronary collateral formation in patients with T2DM and CTO is influenced by various clinical, biochemical and angiographic factors. This information provides insights into the understanding of coronary pathophysiology and searching for potential new therapeutic targets in T2DM.

Association of CXCR4 expression with coronary collateralization in patients with chronic total coronary occlusion: A nested case-control study

OBJECTIVE

CXCR4 signaling contributes to the development and progression of neovascularization. The objective of this study was to investigate whether CXCR4 expression in peripheral CD34+ cells associated with the coronary collateralization (CC) in patients with chronic total coronary occlusion (CTO).

METHODS AND RESULTS

We measured CXCR4 expression in peripheral CD34+ cells and assessed its relation with CC in a nested case-control study including 78 cases and 78 matched controls aged 38-69years, assessed in January 2011 to December 2012 and with at least 1year of follow-up before the index date. Cases were defined as good coronary collateralization (GCC) according to the Rentrop scoring system (Rentrop score of 2 or 3); for each case, one age-matched control with poor coronary collateralization (PCC) (Rentrop score 0 or 1) was randomly selected from the study participants. Demographic, biochemical, and angiographic variables were collected. In multivariate analysis, the OR (95% CI) of CXCR4 expression was 0.018 (0.017 to 0.020) in patients with GCC versus PCC. Independent effect of CXCR4 expression on CC was (OR 0.012, 95% CI 0.010-0.014) when adjusted for other variables. A nonlinear relationship between CXCR4 expression and CC was observed. The CC degree increased when CXCR4 expression exceeded the turning point (30%) (OR 0.025, 95% CI 0.022-0.028; p<0.001). When the CXCR4 expression exceeded 75%, increased CXCR4 level could not promoted CC (OR 0.000, 95% CI 0.008-0.007; p=0.974).

CONCLUSION

Increased CXCR4 level in peripheral CD34+ cells was associated with GCC in patients with CTO.

Repetitive ischemia increases myocardial dimethylarginine dimethylaminohydrolase 1 expression

Pharmacologic inhibition of nitric oxide production inhibits growth of coronary collateral vessels. Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is the major enzyme that degrades asymmetric dimethylarginine (ADMA), a potent inhibitor of nitric oxide synthase. Here we examined regulation of the ADMA-DDAH1 pathway in a canine model of recurrent myocardial ischemia during the time when coronary collateral growth is known to occur. Under basal conditions, DDAH1 expression was non-uniform across the left ventricular (LV) wall, with expression strongest in the subepicardium. In response to ischemia, DDAH1 expression was up-regulated in the midmyocardium of the ischemic zone, and this was associated with a significant reduction in myocardial interstitial fluid (MIF) ADMA. The decrease in MIF ADMA during ischemia was likely due to increased DDAH1 because myocardial protein arginine N-methyl transferase 1 (PRMT1) and the methylated arginine protein content (the source of ADMA) were unchanged or increased, respectively, at this time. The inflammatory mediators interleukin (IL-1β) and tumor necrosis factor (TNF-α) were also elevated in the midmyocardium where DDAH1 expression was increased. Both of these factors significantly up-regulated DDAH1 expression in cultured human coronary artery endothelial cells. Taken together, these results suggest that inflammatory factors expressed in response to myocardial ischemia contributed to up-regulation of DDAH1, which was responsible for the decrease in MIF ADMA.

Relation Between C-X-C Motif Chemokine Receptor 4 Levels and the Presence and Extent of Angiographic Coronary Collaterals in Patients With Chronic Total Coronary Occlusion

Coronary collateral circulation is an alternative source of blood supply to the myocardium in the presence of chronic total coronary occlusion (CTO). C-X-C motif chemokine receptor 4 (CXCR4) signaling usually contributes to neovascularization. Here, we investigate the relation between CXCR4 levels in peripheral blood CD34+ cells and the formation of angiographic coronary collaterals and determine the risk factors that affect CXCR4 expression in patients with CTO. Demographic, biochemical, and angiographic variables were collected from 324 patients with CTO and 90 negative controls. The presence and extent of collaterals were scored according to the Rentrop scoring system (Rentrop's). CXCR4 levels and plasma biochemical factors were detected. Clinical outcomes were collected during a 12-month follow-up. Results show that low (Rentrop's 0 or 1) and high (Rentrop's of 2 or 3) coronary collateralizations were detected in 183 and 141 patients, respectively. The Rentrop scores were positively correlated with CXCR4 levels in patients with CTO. Patients with low CXCR4 expression exhibited worse clinical outcomes compared with those with high CXCR4 expression. Univariate correlation analysis revealed that age of ≥65 years, women, diabetes, increased plasma level of high-sensitivity C-reactive protein (hs-CRP), and N-terminal brain-type natriuretic peptide were associated with low CXCR4 levels. In conclusion, CXCR4 levels were positively correlated with the presence and extent of angiographic coronary collaterals in patients with CTO. Elder age, women, diabetes, increased plasma level of high-sensitivity C-reactive protein, and N-terminal brain-type natriuretic peptide may be risk factors of CXCR4 expression.

Higher circulating levels of chemokines CXCL10, CCL20 and CCL22 in patients with ischemic heart disease

Recruitment of leukocytes is one of the earliest events in the pathogenesis of ischemic heart disease (IHD) and chemokines play an important role in the migration of these cells into the inflammation sites. The aim of this study was to evaluate the CXCL10, CCL20 and CCL22 levels and the single nucleotide polymorphisms (SNPs) rs4508917, rs6749704 and rs4359426 in chemokine genes in patients with IHD to clarify any association. A total of 300 patients with IHD as having acute myocardial infarction (AMI; n=100), stable angina (SA; n=100) or unstable angina (UA; n=100) and 100 healthy subjects as a control group were enrolled to study. Serum samples from all participants were tested for the CXCL10, CCL20 and CCL22 levels by using ELISA. The SNPs were determined by polymerase chain reaction-restriction length polymorphism (PCR-RFLP) method. The mean serum concentrations of CXCL10, CCL20 and CCL22 in AMI patients (395.97±21.20Pg/mL, 108.38±10.31Pg/mL and 1852.58±205.77Pg/mL), SA patients (405.48±27.36Pg/mL, 90.20±7.69Pg/mL and 2322.04±231.23Pg/mL) and UA patients (396.69±22.79Pg/mL, 141.87±18.10Pg/mL and 2754.89±211.70Pg/mL) were significantly higher than in the healthy group (179.38±8.85Pg/mL, 51.92±4.62Pg/mL and 451.82±23.76Pg/mL, respectively; P<0.001). Similarly, the serum levels of CXCL10, CCL20 and CCL22 in total IHD patients (399.38±13.77Pg/mL, 113.49±7.48Pg/mL and 2309.84±126.39Pg/mL, respectively) were also significantly higher as compared with healthy subjects (P<0.001). The serum levels of CCL20 and CCL22 in UA patients were significantly higher than those in SA and AMI patients, respectively (P<0.01 and P<0.003, respectively). The serum levels of CXCL10 and CCL20 in diabetic patients were significantly higher in comparison to non-diabetic patients (P<0.05 and P<0.02, respectively). The serum levels of CCL22 in dyslipidemic- and obese patients were also significantly higher in comparison with non-dyslipidemic- and non-obese patients, correspondingly (P<0.05 and P<0.01, respectively). There were no significant differences between men and women or between patients who treated with statin, aspirin, β-blockers or angiotensin converting enzyme (ACE) inhibitors and patients without mentioned treatment regarding the levels of chemokines. The frequency of the GG genotype at SNP rs4508917 in CXCL10 gene was higher, whereas the frequency of the AA genotype at SNP rs4359426 in CCL22 gene was lower in total patients with IHD as compared with healthy subjects (P<0.04 and P<0.002, respectively). These results showed that the higher levels of CXCL10, CCL20 and CCL22 were associated with IHD. The serum levels of chemokines may influence by the certain traditional risk factors of IHD and some studied SNPs, but did not influence by treatment and gender of patients.

Biomarkers of coronary endothelial health: correlation with invasive measures of collateral function, flow and resistance in chronically occluded coronary arteries and the effect of recanalization

OBJECTIVES

In the presence of a chronically occluded coronary artery, the collateral circulation matures by a process of arteriogenesis; however, there is considerable variation between individuals in the functional capacity of that collateral network. This could be explained by differences in endothelial health and function. We aimed to examine the relationship between the functional extent of collateralization and levels of biomarkers that have been shown to relate to endothelial health.

METHODS

We measured four potential biomarkers of endothelial health in 34 patients with mature collateral networks who underwent a successful percutaneous coronary intervention (PCI) for a chronic total coronary occlusion (CTO) before PCI and 6-8 weeks after PCI, and examined the relationship of biomarker levels with physiological measures of collateralization.

RESULTS

We did not find a significant change in the systemic levels of sICAM-1, sE-selectin, microparticles or tissue factor 6-8 weeks after PCI. We did find an association between estimated retrograde collateral flow before CTO recanalization and lower levels of sICAM-1 (r=0.39, P=0.026), sE-selectin (r=0.48, P=0.005) and microparticles (r=0.38, P=0.03).

CONCLUSION

Recanalization of a CTO and resultant regression of a mature collateral circulation do not alter systemic levels of sICAM-1, sE-selectin, microparticles or tissue factor. The identified relationship of retrograde collateral flow with sICAM-1, sE-selectin and microparticles is likely to represent an association with an ability to develop collaterals rather than their presence and extent.

Emerging importance of chemokine receptor CXCR3 and its ligands in cardiovascular diseases

The CXC chemokines, CXCL4, -9, -10, -11, CXCL4L1, and the CC chemokine CCL21, activate CXC chemokine receptor 3 (CXCR3), a cell-surface G protein-coupled receptor expressed mainly by Th1 cells, cytotoxic T (Tc) cells and NK cells that have a key role in immunity and inflammation. However, CXCR3 is also expressed by vascular smooth muscle and endothelial cells, and appears to be important in controlling physiological vascular function. In the last decade, evidence from pre-clinical and clinical studies has revealed the participation of CXCR3 and its ligands in multiple cardiovascular diseases (CVDs) of different aetiologies including atherosclerosis, hypertension, cardiac hypertrophy and heart failure, as well as in heart transplant rejection and transplant coronary artery disease (CAD). CXCR3 ligands have also proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, suggesting an underlining pathophysiological relation between levels of these chemokines and the development of adverse cardiac remodelling. The observation that several of the above-mentioned chemokines exert biological actions independent of CXCR3 provides both opportunities and challenges for developing effective drug strategies. In this review, we provide evidence to support our contention that CXCR3 and its ligands actively participate in the development and progression of CVDs, and may additionally have utility as diagnostic and prognostic biomarkers.

Serum Cystatin C Reflects Angiographic Coronary Collateralization in Stable Coronary Artery Disease Patients with Chronic Total Occlusion

OBJECTIVE

We investigated whether and to what extent cystatin C was associated with angiographic coronary collateralization in patients with stable coronary artery disease and chronic total occlusion.

METHODS

Serum levels of cystatin C and high-sensitive C-reactive protein (hsCRP) and glomerular filtration rate (GFR) were determined in 866 patients with stable angina and angiographic total occlusion of at least one major coronary artery. The degree of collaterals supplying the distal aspect of a total occlusion from the contra-lateral vessel was graded as poor (Rentrop score of 0 or 1) or good coronary collateralization (Rentrop score of 2 or 3).

RESULTS

In total, serum cystatin C was higher in patients with poor collateralization than in those with good collateralization (1.08 ± 0.32 mg/L vs. 0.90 ± 0.34 mg/L, P < 0.001), and correlated inversely with Rentrop score (adjusted Spearmen's r = -0.145, P < 0.001). The prevalence of poor coronary collateralization increased stepwise with increasing cystatin C quartiles (P for trend < 0.001). After adjusting for age, gender, risk factors for coronary artery disease, GFR and hsCRP, serum cystatin C ≥ 0.97 mg/L remained independently associated with poor collateralization (OR 2.374, 95% CI 1.660 ~ 3.396, P < 0.001). The diagnostic value of cystatin C levels for detecting poor coronary collateralization persisted regardless of age, gender, presence or absence of diabetes, hypertension or renal dysfunction.

CONCLUSIONS

Serum cystatin C reflects angiographic coronary collateralization in patients with stable coronary artery disease, and cystatin C ≥ 0.97 mg/L indicates a great risk of poor coronary collaterals.

The multifaceted functions of CXCL10 in cardiovascular disease

C-X-C motif ligand 10 (CXCL10), or interferon-inducible protein-10, is a small chemokine belonging to the CXC chemokine family. Its members are responsible for leukocyte trafficking and act on tissue cells, like endothelial and vascular smooth muscle cells. CXCL10 is secreted by leukocytes and tissue cells and functions as a chemoattractant, mainly for lymphocytes. After binding to its receptor CXCR3, CXCL10 evokes a range of inflammatory responses: key features in cardiovascular disease (CVD). The role of CXCL10 in CVD has been extensively described, for example for atherosclerosis, aneurysm formation, and myocardial infarction. However, there seems to be a discrepancy between experimental and clinical settings. This discrepancy occurs from differences in biological actions between species (e.g. mice and human), which is dependent on CXCL10 signaling via different CXCR3 isoforms or CXCR3-independent signaling. This makes translation from experimental to clinical settings challenging. Furthermore, the overall consensus on the actions of CXCL10 in specific CVD models is not yet reached. The purpose of this review is to describe the functions of CXCL10 in different CVDs in both experimental and clinical settings and to highlight and discuss the possible discrepancies and translational difficulties. Furthermore, CXCL10 as a possible biomarker in CVD will be discussed.

Immunological profile of silent brain infarction and lacunar stroke

Neuroinflammation is believed to be involved in the pathophysiological mechanisms of silent brain infarcts (SBI). However, the immunological profile of SBI has been scarcely investigated. In the context of a national research project named SILENCE, aimed at investigating clinical, biochemical and pathogenic features of SBI, we have measured the plasma profile of some inflammatory-related molecules in SBI patients (n = 21), patients with recent lacunar infarcts (LI, n = 28) and healthy controls (n = 31), consecutively enrolled in four Italian centres. A panel of chemokines (MIG, CTACK, IL16, SDF1a, MCP1), growth factors (SCF, SCGFb, HGF, IL3), immunoglobulin-type adhesion molecules (ICAM1, VCAM1), proinflammatory cytokines (IL18, INFa2, MIF, IL12p40), cell surface receptors on T-cells (IL2Ra), and inductors of apoptosis (TRAIL) was assessed in plasma samples by Luminex xMAP™ technology. Immunological parameters were compared using non-parametric statistics and performance to distinguish SBI and LI was evaluated by receiver operating characteristic (ROC) analysis. Plasma levels of ICAM1 were significantly higher in both SBI and LI patients as compared to controls (SBI≥LI>Ctrl). A different trend was observed for IL16 (SBI<LI>Ctrl), SCF (LI<SBI>Ctrl) and SCGFb (SBI>LI<Ctrl). SBI subjects had significantly increased levels of MIG when compared to controls (LI≤SBI>Ctrl) and IL18 when compared to LI patients (Ctrl≤SBI>LI). All the other immunological markers did not significantly differ among groups. According to ROC analysis, the best predictor for SBI condition was the chemokine MIG (AUC = 0.84, sensitivity 86%, specificity 77%), while SCF had the best performance in distinguishing LI patients (AUC = 0.84, sensitivity 86%, specificity 68%). These results confirm the involvement of inflammatory processes in cerebrovascular disorders, particularly in SBI, a very common age-related condition. The differences in plasma profile of inflammatory molecules may underlie different pathological mechanisms in SBI and LI patients.

Analyzing migratory properties of human CD133(+) stem cells in vivo after intraoperative sternal bone marrow isolation

Human bone marrow stem cell populations have been applied for cardiac regeneration purposes within different clinical settings in the recent past. The migratory capacity of applied stem cell populations towards injured tissue, after undergoing specific peri-interventional harvesting and isolation procedures, represents a key factor limiting therapeutic efficacy. We therefore aimed at analyzing the migratory capacity of human cluster of differentiation (CD) 133(+) bone marrow stem cells in vivo after intraoperative harvesting from the sternal bone marrow. Human CD133(+) bone marrow stem cells were isolated from the sternal bone marrow of patients undergoing cardiac surgery at our institution. Migratory capacity towards stromal cell-derived factor-1α (SDF-1α) gradients was tested in vitro and in vivo by intravital fluoresecence microscopy, utilizing the cremaster muscle model in severe combined immunodeficient (SCID) mice and analyzing CD133(+) cell interaction with the local endothelium. Furthermore, the role of a local inflammatory stimulus for CD133(+) cell interaction with the endothelium was studied. In order to describe endothelial response upon chemokine stimulation laser scanning microscopy of histological cremaster muscle samples was performed. SDF-1α alone was capable to induce relevant early CD133(+) cell interaction with the endothelium, indicated by the percentage of rolling CD133(+) cells (45.9±1.8% in "SDF-1" vs. 17.7±2.7% in "control," p<0.001) and the significantly reduced rolling velocity after SDF-1α treatment. Furthermore, SDF-1α induced firm endothelial adhesion of CD133(+) cells in vivo. Firm endothelial adhesion, however, was significantly enhanced by additional inflammatory stimulation with tumor necrosis factor-α (TNF-α) (27.9±4.3 cells/mm(2)in "SDF-1 + TNF" vs. 2.2±1.1 cells/mm(2) in "control," p<0.001). CD133(+) bone marrow stem cells exhibit sufficient in vivo homing towards SDF-1α gradients in an inflammatory microenvironment after undergoing standardized intraoperative harvesting and isolation from the sternal bone marrow.

Dose-dependent Effect of Statin Therapy on Circulating CXCL12 Levels in Patients with Hyperlipidemia

BACKGROUND

HMG-CoA reductase inhibitors (statins) have pleiotropic effects that are independent of cholesterol-lowering, including a dose-dependent effect on angiogenesis. Angiogenesis plays a critical role both in vascularization of the chronically ischemic myocardium and in stabilization of atherosclerotic plaques. Chemokines, a family of structurally-related cytokine molecules, exert diverse biological functions including control of angiogenesis. The effect of statin therapy on angiogenic and angiostatic chemokines has not been evaluated extensively. We sought to test the hypothesis that, in subjects with hyperlipidemia, statin therapy influences plasma levels of angiogenic and angiostatic chemokines in a dose-dependent manner.

METHODS

We prospectively collected demographic, angiographic and laboratory data from subjects with a history of hyperlipidemia who were either untreated or on statin therapy. A peripheral blood sample was obtained for measurement of plasma angiogenic and angiostatic chemokines. Multivariable analysis using logistic regression was performed adjusting for the following variables: age, gender, prior myocardial infarction, and chronic administration of aspirin, clopidogrel, insulin, oral hypoglycemic agents, beta-blockers and calcium channel blockers.

RESULTS

168 patients on statin therapy (48 on low-dose, defined as <10mg atorvastatin-equivalent, and 120 on high-dose, defined as ≥10mg atorvastatin-equivalent dose) and 11 subjects from the same database who had a history of hyperlipidemia but who were not on statins were enrolled. There were no significant differences in baseline demographics, co-morbidities, lipid panels, other medications, or angiographic data between the groups. The angiogenic chemokines CXCL1 and CXCL12 levels were significantly different across the groups. Median levels of CXCL1 were highest in subjects not on statin therapy. Compared to subjects either not on statin therapy or on low-dose statins, those taking high-dose statins had lower median values of CXCL12 (2316 [2255-11071], vs 2362 [2016-10622], vs 2189 [1968-2705] pg/mL, p=0.042). On multivariate analysis, CXCL12 remained the only factor that was strongly and inversely associated with statin dose at the 95% level (p=0.011).

CONCLUSIONS

Compared to no therapy or low-dose statin therapy, treatment with high-doses of HMG-CoA reductase inhibitors is associated with decreased circulating CXCL12 levels in subjects with hyperlipidemia, and CXCL12 is strongly and inversely associated with statin dose. Additional studies are needed to confirm this finding in other cohorts and to determine if high-dose statins affect angiogenesis in patients.

CXCL5 polymorphisms are associated with variable blood pressure in cardiovascular disease-free adults

Objective

Leukocyte count has been associated with blood pressure, hypertension, and hypertensive complications. We hypothesized that polymorphisms in the CXCL5 gene, which encodes the neutrophilic chemokine ENA-78, are associated with blood pressure in cardiovascular disease (CVD)-free adults and that these polymorphisms are functional.

Methods and results

A total of 192 community-dwelling participants without CVD or risk equivalents were enrolled. Two CXCL5 polymorphisms (−156 G > C (rs352046) and 398 G > A (rs425535)) were tested for associations with blood pressure. Allele-specific mRNA expression in leukocytes was also measured to determine whether heterozygosity was associated with allelic expression imbalance. In −156 C variant carriers, systolic blood pressure (SBP) was 7 mmHg higher than in −156 G/G wild-type homozygotes (131 ± 17 vs. 124 ± 14 mmHg; P = 0.008). Similarly, diastolic blood pressure (DBP) was 4 mmHg higher in −156 C variant carriers (78 ± 11 vs. 74 ± 11 mmHg; P = 0.013). In multivariate analysis of SBP, age, sex, body mass index, and the −156 G > C polymorphism were identified as significant variables. Age, sex, and the −156 G > C SNP were further associated with DBP, along with white blood cells. Allelic expression imbalance and significantly higher circulating ENA-78 concentrations were noted for variant carriers.

Conclusion

CXCL5 gene polymorphisms are functional and associated with variable blood pressure in CVD-free individuals. The role of CXCL5 as a hypertension- and CVD-susceptibility gene should be further explored.

Why is coronary collateral growth impaired in type II diabetes and the metabolic syndrome?

Type II diabetes and the metabolic syndrome are strong predictors of severity of occlusive coronary disease and poorer outcomes of coronary revascularization therapies. Coronary collateral growth can provide an alternative or accessory pathway of revascularization. However, collateral growth is impaired in type II diabetes and the metabolic syndrome. Although many factors necessary for collateral growth are known and many interventions have shown promising results in animal studies, not a single attempt to induce coronary collateral growth in human clinical trials has led to satisfactory results. Accordingly, the first part of this review outlines the known deleterious effects of diabetes and the metabolic syndrome on factors necessary for collateral growth, including pro-angiogenic growth factors, endothelial function, the redox state of the coronary circulation, intracellular signaling, leukocytes and bone marrow-derived progenitors cells. The second section highlights the gaps in our current knowledge of how these factors interact with the radically altered environment of the coronary circulation in diabetes and the metabolic syndrome. The interplay between these pathologies and inadequately explored areas related to the temporal regulation of collateral remodeling and the roles of the extracellular matrix, vascular cell phenotype and pro-inflammatory cytokines are emphasized with implications to development of efficient therapies.