A potential role of the CXC chemokine GROalpha in atherosclerosis and plaque destabilization: downregulatory effects of statins

Identification of a functional missense variant in the matrix metallopeptidase 10 (MMP10) gene in two families with premature myocardial infarction

A positive family history is a major independent risk factor for atherosclerosis, and genetic variation is an important aspect of cardiovascular disease research. We identified a heterozygous missense variant p.L245P in the MMP10 gene in two families with premature myocardial infarction using whole-exome sequencing. The aim of this study was to investigate the consequences of this variant using in-silico and functional in-vitro assays. Molecular dynamics simulations were used to analyze protein interactions, calculate free binding energy, and measure the volume of the substrate-binding cleft of MMP10-TIMP1 models. The p.L245P variant showed an altered protein surface, different intra- and intermolecular interactions of MMP10-TIMP1, a lower total free binding energy between MMP10-TIMP1, and a volume-minimized substrate-binding cleft of MMP10 compared to the wild-type. For the functional assays, human THP-1 cells were transfected with plasmids containing MMP10 cDNA carrying the p.L245P and wild-type variant and differentiated into macrophages. Macrophage adhesion and migration assays were then conducted, and pro-inflammatory chemokine levels were evaluated. The p.L245P variant led to macrophages that were more adherent, less migratory, and secreted higher levels of the pro-inflammatory chemokines CXCL1 and CXCL8 than wild-type macrophages. Thus, the p.L245P variant in MMP10 may influence the pathogenesis of atherosclerosis in families with premature myocardial infarction by altering protein - protein interactions, macrophage adhesion and migration, and expression of pro-inflammatory chemokines, which may increase plaque rupture. These results could contribute to the development of selective MMP10 inhibitors and reduce the risk of atherosclerosis in families with a history of premature myocardial infarction.

CXCL1 as a Potential Biomarker of Plaque Instability in Carotid Stenosis. Preliminary Report

Biomarkers of atherosclerotic plaque instability are needed. This study aimed to evaluate the level of chemokine CXCL1 (CXC motif ligand 1) in plasma and atherosclerotic plaques in patients with carotid stenosis and correlate that with plaque morphology. The study group included 82 patients (30 women and 52 men) aged 50-90 years (mean 68.1 ± 8.9) who underwent elective carotid endarterectomy. The obtained atherosclerotic plaques were macroscopically and microscopically assessed according to the American Heart Association (AHA) classification. Fifty-one (62.2%) and 31 (37.8%) of the plaques were unstable and stable, respectively. The mean concertation of CXCL1 in plaques in asymptomatic and symptomatic patients was 0.00 (±0.00) vs 88.90 (±95.19) pg/ml, respectively (P = 0.000). The mean plasma concentration of CXCL1 in the study group was 42.40 (±85.79) pg/ml, while in the control group (healthy volunteers without lesions in the carotid arteries) it was 0.00 pg/mL (±0.00) (P = 0.000). The mean plasma CXCL1 concertation in asymptomatic and symptomatic patients was 22.08 (±49.13) versus 67.72 (±107.91) pg/ml, respectively (P = 0.031). Significantly higher CXCL1 concentration in atherosclerotic plaques and plasma in symptomatic patients compared with asymptomatic patients probably resulted from unstable lesions in the carotid arteries.

Interaction between peripheral blood mononuclear cells and Trypanosoma cruzi-infected adipocytes: implications for treatment failure and induction of immunomodulatory mechanisms in adipose tissue

Background/Introduction

Adipose tissue (AT) has been highlighted as a promising reservoir of infection for viruses, bacteria and parasites. Among them is Trypanosoma cruzi, which causes Chagas disease. The recommended treatment for the disease in Brazil is Benznidazole (BZ). However, its efficacy may vary according to the stage of the disease, geographical origin, age, immune background of the host and sensitivity of the strains to the drug. In this context, AT may act as an ally for the parasite survival and persistence in the host and a barrier for BZ action. Therefore, we investigated the immunomodulation of T. cruzi-infected human AT in the presence of peripheral blood mononuclear cells (PBMC) where BZ treatment was added.

Methods

We performed indirect cultivation between T. cruzi-infected adipocytes, PBMC and the addition of BZ. After 72h of treatment, the supernatant was collected for cytokine, chemokine and adipokine assay. Infected adipocytes were removed to quantify T. cruzi DNA, and PBMC were removed for immunophenotyping.

Results

Our findings showed elevated secretion of interleukin (IL)-6, IL-2 and monocyte chemoattractant protein-1 (MCP-1/CCL2) in the AT+PBMC condition compared to the other controls. In contrast, there was a decrease in tumor necrosis factor (TNF) and IL-8/CXCL-8 in the groups with AT. We also found high adipsin secretion in PBMC+AT+T compared to the treated condition (PBMC+AT+T+BZ). Likewise, the expression of CD80+ and HLA-DR+ in CD14+ cells decreased in the presence of T. cruzi.

Discussion

Thus, our findings indicate that AT promotes up-regulation of inflammatory products such as IL-6, IL-2, and MCP-1/CCL2. However, adipogenic inducers may have triggered the downregulation of TNF and IL-8/CXCL8 through the peroxisome proliferator agonist gamma (PPAR-g) or receptor expression. On the other hand, the administration of BZ only managed to reduce inflammation in the microenvironment by decreasing adipsin in the infected culture conditions. Therefore, given the findings, we can see that AT is an ally of the parasite in evading the host's immune response and the pharmacological action of BZ.

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.

High Interleukin-8 Levels Associated With Decreased Survival in Patients With Cirrhosis Following Transjugular Intrahepatic Portosystemic Shunt

Background

Serum cytokines—reflecting systemic inflammation has been associated with the risk of decompensation and mortality in patients with cirrhosis. However, the role of systemic inflammation in patients with cirrhosis undergoing transjugular intrahepatic portosystemic shunt procedure remains unknown.

Patients and Methods

Patients with cirrhosis who received transjugular intrahepatic portosystemic shunt between June 2015 and September 2017 were included. Portal and hepatic venous blood samples were obtained intraoperatively; serum cytokine levels (IL-10, IL-17A, IL-1RA, IL-8, and CXCL10) were measured in 105 patients. Associations with survival and other outcomes during long-term follow-up (median: 1,564 days) were assessed using logistic regression.

Results

IL-17A and CXCL10 levels were higher in the portal than in the hepatic veins, whereas IL-1RA levels were higher in the hepatic than in the portal veins. However, IL-8 or IL-10 levels between hepatic and portal veins showed no differences. Multivariate analysis demonstrated that Child–Pugh scores (P = 0.017, HR: 1.484, 95% CI: 1.072–2.055) and IL-8 level in hepatic veins (P < 0.001, HR: 1.043, 95% CI: 1.019–1.068) were independent predictors for mortality during long-term follow-up, with an optimal cut-off of 5.87 pg/ml for IL-8 in hepatic veins. Patients with hepatic IL-8 levels < 5.87 pg/ml had significantly higher cumulative survival rates (98.4 vs. 72.9% at 1 year, 98.4 vs. 65.3% at 2 years, 96.7 vs. 60.3% at 3 years, 94.2 vs. 60.3% at 4 years; P < 0.0001).

Conclusions

IL-8 levels in hepatic veins may reflect liver cirrhosis severity. Elevated IL-8 levels suggest shorter survival in patients receiving TIPS.

High-Fat Diet Enhances Neutrophil Adhesion in LDLR-Null Mice Via Hypercitrullination of Histone H3

Neutrophil adhesion on the atheroprone femoral artery of high-fat diet-fed low-density lipoprotein receptor-null mice was enhanced more than in wild-type mice. The inhibition of histone H3 citrullination of neutrophils reversed the enhancement of neutrophil adhesion, suggesting that hypercitrullination contributes to enhanced neutrophil adhesion. Furthermore, pemafibrate reduced the citrullination of histone H3 in these mice. Therefore, the hypercitrullination of histone H3 in neutrophils contributes to atherosclerotic vascular inflammation.

Identification of key pathways and core genes involved in atherosclerotic plaque progression

Background

Atherosclerosis leads to the occurrence of cardiovascular diseases. However, the molecular mechanisms that contribute to atherosclerotic plaque rupture are incompletely characterized. We aimed to identify the genes related to atherosclerotic plaque progression that could serve as novel biomarkers and interventional targets for plaque progression.

Methods

The datasets of GSE28829 in early vs. advanced atherosclerotic plaques and those of GSE41571 in stable vs. ruptured plaques from Gene Expression Omnibus (GEO) were analyzed by using bioinformatics methods. In addition, we used quantitative reverse transcription polymerase chain reaction (qRT-PCR) to verify the expression level of core genes in a mouse atherosclerosis model.

Results

There were 29 common differentially expressed genes (DEGs) between the GSE28829 and GSE41571 datasets, and the DEGs were mainly enriched in the chemokine signaling pathway and the Staphylococcus aureus infection pathway (P<0.05). We identified 6 core genes (FPR3, CCL18, MS4A4A, CXCR4, CXCL2, and C1QB) in the protein-protein interaction (PPI) network, 3 of which (CXCR4, CXCL2, and CCL18) were markedly enriched in the chemokine signaling pathway. qRT-PCR analysis showed that the messenger RNA levels of two core genes (CXCR4 and CXCL2) increased significantly during plaque progression in the mouse atherosclerosis model.

Conclusions

In summary, bioinformatics techniques proved useful for the screening and identification of novel biomarkers of disease. A total of 29 DEGs and 6 core genes were linked to atherosclerotic plaque progression, in particular the CXCR4 and CXCL2 genes.

FAK and Pyk2 activity promote TNF-α and IL-1β-mediated pro-inflammatory gene expression and vascular inflammation

Protein tyrosine kinase (PTK) activity has been implicated in pro-inflammatory gene expression following tumor necrosis factor-α (TNF-α) or interkeukin-1β (IL-1β) stimulation. However, the identity of responsible PTK(s) in cytokine signaling have not been elucidated. To evaluate which PTK is critical to promote the cytokine-induced inflammatory cell adhesion molecule (CAM) expression including VCAM-1, ICAM-1, and E-selectin in human aortic endothelial cells (HAoECs), we have tested pharmacological inhibitors of major PTKs: Src and the focal adhesion kinase (FAK) family kinases - FAK and proline-rich tyrosine kinase (Pyk2). We found that a dual inhibitor of FAK/Pyk2 (PF-271) most effectively reduced all three CAMs upon TNF-α or IL-1β stimulation compared to FAK or Src specific inhibitors (PF-228 or Dasatinib), which inhibited only VCAM-1 expression. In vitro inflammation assays showed PF-271 reduced monocyte attachment and transmigration on HAoECs. Furthermore, FAK/Pyk2 activity was not limited to CAM expression but was also required for expression of various pro-inflammatory molecules including MCP-1 and IP-10. Both TNF-α and IL-1β signaling requires FAK/Pyk2 activity to activate ERK and JNK MAPKs leading to inflammatory gene expression. Knockdown of either FAK or Pyk2 reduced TNF-α-stimulated ERK and JNK activation and CAM expression, suggesting that activation of ERK or JNK is specific through FAK and Pyk2. Finally, FAK/Pyk2 activity is required for VCAM-1 expression and macrophage recruitment to the vessel wall in a carotid ligation model in ApoE-/- mice. Our findings define critical roles of FAK/Pyk2 in mediating inflammatory cytokine signaling and implicate FAK/Pyk2 inhibitors as potential therapeutic agents to treat vascular inflammatory disease such as atherosclerosis.

The temporal pattern of immune and inflammatory proteins prior to a recurrent coronary event in post-acute coronary syndrome patients

PURPOSE

We assessed the temporal pattern of 29 immune and inflammatory proteins in post-acute coronary syndrome (ACS) patients, prior to the development of recurrent ACS.

METHODS

High-frequency blood sampling was performed in 844 patients admitted for ACS during one-year follow-up. We conducted a case-control study on the 45 patients who experienced reACS (cases) and two matched event-free patients (controls) per case. Olink Proteomics' immunoassay was used to obtain serum levels of the 29 proteins, expressed in an arbitrary unit on the log2-scale (Normalized Protein eXpression, NPX). Linear mixed-effects models were applied to examine the temporal pattern of the proteins, and to illustrate differences between cases and controls.

RESULTS

Mean age was 66 ± 12 years and 80% were men. Cases and controls had similar baseline clinical characteristics. During the first 30 days, and after multiple testing correction, cases had significantly higher serum levels of CXCL1 (difference of 1.00 NPX, p = 0.002), CD84 (difference of 0.64 NPX, p = 0.002) and TNFRSF10A (difference of 0.41 NPX, p < 0.001) than controls. After 30 days, serum levels of all 29 proteins were similar in cases and controls. In particular, no increase was observed prior to reACS.

CONCLUSIONS

Among 29 immune and inflammatory proteins, CXCL1, CD84 and TNFRSF10A were associated with early reACS after initial ACS-admission.

Vascular Stem/Progenitor Cell Migration and Differentiation in Atherosclerosis

SIGNIFICANCE

Atherosclerosis is a major cause for the death of human beings, and it takes place in large- and middle-sized arteries. The pathogenesis of the disease has been widely investigated, and new findings on vascular stem/progenitor cells could have an impact on vascular regeneration. Recent Advances: Recent studies have shown that abundant stem/progenitor cells present in the vessel wall are mainly responsible for cell accumulation in the intima during vascular remodeling. It has been demonstrated that the mobilization and recruitment of tissue-resident stem/progenitor cells give rise to endothelial and smooth muscle cells (SMCs) that participate in vascular repair and remodeling such as neointimal hyperplasia and arteriosclerosis. Interestingly, cell lineage tracing studies indicate that a large proportion of SMCs in neointimal lesions is derived from adventitial stem/progenitor cells.

CRITICAL ISSUES

The influence of stem/progenitor cell behavior on the development of atherosclerosis is crucial. An understanding of the regulatory mechanisms that control stem/progenitor cell migration and differentiation is essential for stem/progenitor cell therapy for vascular diseases and regenerative medicine.

FUTURE DIRECTIONS

Identification of the detailed process driving the migration and differentiation of vascular stem/progenitor cells during the development of atherosclerosis, discovery of the environmental cues, and signaling pathways that control cell fate within the vasculature will facilitate the development of new preventive and therapeutic strategies to combat atherosclerosis. Antioxid. Redox Signal. 00, 000-000.

Endothelial progenitor cells in age-related vascular remodeling

Accumulating evidence has demonstrated that endothelial progenitor cells (EPCs) could facilitate the reendothelialization of injured arteries by replacing the dysfunctional endothelial cells, thereby suppressing the formation of neointima. Meanwhile, other findings suggest that EPCs may be involved in the pathogenesis of age-related vascular remodeling. This review is presented to summarize the characteristics of EPCs and age-related vascular remodeling. In addition, the role of EPCs in age-related vascular remodeling and possible solutions for improving the therapeutic effects of EPCs in the treatment of age-related diseases are discussed.

Association of Sleep Quality With Cardiovascular Disease Risk and Mental Health in Law Enforcement Officers

OBJECTIVES

The aim of the study was to determine whether sleep quality is associated with an increased risk for cardiovascular disease (CVD) or worsened mental health.

METHODS

Self-reported sleep quality, 35 inflammatory factors, CVD risk factors, personal stress, police operational and organizational stress, social support, depressive symptoms, and health-related quality of life were compared among a cohort of officers.

RESULTS

Of 379 officers, 39% and 27% had poor and borderline sleep quality. Sleep quality was not associated with either an altered inflammatory profile or worsened CVD risk factors. Compared with good sleepers, borderline and poor sleepers reported increased personal stress, police organizational and operational stress, and depressive symptoms, but decreased health-related quality of life.

CONCLUSIONS

Poor sleep quality is prevalent in the law enforcement profession and is associated with worsened mental health but not with an increased risk for CVD.

Interleukin-33 induces growth-regulated oncogene-α expression and secretion in human umbilical vein endothelial cells

Although interleukin-33 (IL-33), a member of the IL-1 cytokine family, plays proinflammatory roles in immune cells as an "alarmin," little is known regarding the biological actions of IL-33 on vascular endothelial cells. To investigate the effects of IL-33 on vascular endothelial cells, we first screened the IL-33-regulated proteins in human umbilical vein endothelial cells (HUVECs) using a dot blot array and observed that IL-33 markedly increased growth-regulated oncogene-α (GRO-α), a chemokine that is also known as chemokine (C-X-C motif) ligand 1 (CXCL1). Real-time reverse transcription PCR and ELISA demonstrated that IL-33 induced GRO-α expression and secretion in HUVECs in a dose- and a time-dependent manner. Western immunoblot assay revealed that IL-33 activated the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun NH₂-terminal kinase (JNK). In addition, translocation of nuclear factor-κB (NF-κB) p65 to the nucleus of HUVECs was observed by IL-33 stimulation. Furthermore, treatment with pharmacological inhibitors against ERK1/2 (PD98059), JNK (SP600125), or NF-κB (BAY11-7085) significantly suppressed IL-33-induced GRO-α gene expression and secretion from HUVECs. Moreover, immunohistochemical staining demonstrated that IL-33 and GRO-α coexpressed in the endothelium of human carotid atherosclerotic plaque. Taken together, the present study indicates that IL-33 localized in the human atherosclerotic plaque increases GRO-α mRNA expression and protein secretion via activation of ERK1/2, JNK, and NF-κB in HUVECs, suggesting that IL-33 plays an important role in the pathophysiology and development of atherosclerosis.

Understanding gene expression in coronary artery disease through global profiling, network analysis and independent validation of key candidate genes

Molecular mechanism underlying the patho-physiology of coronary artery disease (CAD) is complex. We used global expression profiling combined with analysis of biological network to dissect out potential genes and pathways associated with CAD in a representative case-control Asian Indian cohort. We initially performed blood transcriptomics profiling in 20 subjects, including 10 CAD patients and 10 healthy controls on the Agilent microarray platform. Data was analysed with Gene Spring Gx12.5, followed by network analysis using David v 6.7 and Reactome databases. The most significant differentially expressed genes from microarray were independently validated by real time PCR in 97 cases and 97 controls. A total of 190 gene transcripts showed significant differential expression (fold change>2,P<0.05) between the cases and the controls of which 142 genes were upregulated and 48 genes were downregulated. Genes associated with inflammation, immune response, cell regulation, proliferation and apoptotic pathways were enriched, while inflammatory and immune response genes were displayed as hubs in the network, having greater number of interactions with the neighbouring genes. Expression of EGR1/2/3, IL8, CXCL1, PTGS2, CD69, IFNG, FASLG, CCL4, CDC42, DDX58, NFKBID and NR4A2 genes were independently validated; EGR1/2/3 and IL8 showed >8-fold higher expression in cases relative to the controls implying their important role in CAD. In conclusion, global gene expression profiling combined with network analysis can help in identifying key genes and pathways for CAD.

Dietary nitrate improves vascular function in patients with hypercholesterolemia: a randomized, double-blind, placebo-controlled study

BACKGROUND

The beneficial cardiovascular effects of vegetables may be underpinned by their high inorganic nitrate content.

OBJECTIVE

We sought to examine the effects of a 6-wk once-daily intake of dietary nitrate (nitrate-rich beetroot juice) compared with placebo intake (nitrate-depleted beetroot juice) on vascular and platelet function in untreated hypercholesterolemics.

DESIGN

A total of 69 subjects were recruited in this randomized, double-blind, placebo-controlled parallel study. The primary endpoint was the change in vascular function determined with the use of ultrasound flow-mediated dilatation (FMD).

RESULTS

Baseline characteristics were similar between the groups, with primary outcome data available for 67 patients. Dietary nitrate resulted in an absolute increase in the FMD response of 1.1% (an ∼24% improvement from baseline) with a worsening of 0.3% in the placebo group (P < 0.001). A small improvement in the aortic pulse wave velocity (i.e., a decrease of 0.22 m/s; 95% CI: -0.4, -0.3 m/s) was evident in the nitrate group, showing a trend (P = 0.06) to improvement in comparison with the placebo group. Dietary nitrate also caused a small but significant reduction (7.6%) in platelet-monocyte aggregates compared with an increase of 10.1% in the placebo group (P = 0.004), with statistically significant reductions in stimulated (ex vivo) P-selectin expression compared with the placebo group (P < 0.05) but no significant changes in unstimulated expression. No adverse effects of dietary nitrate were detected. The composition of the salivary microbiome was altered after the nitrate treatment but not after the placebo treatment (P < 0.01). The proportions of 78 bacterial taxa were different after the nitrate treatment; of those taxa present, 2 taxa were responsible for >1% of this change, with the proportions of Rothia mucilaginosa trending to increase and Neisseria flavescens (P < 0.01) increased after nitrate treatment relative to after placebo treatment.

CONCLUSIONS

Sustained dietary nitrate ingestion improves vascular function in hypercholesterolemic patients. These changes are associated with alterations in the oral microbiome and, in particular, nitrate-reducing genera. Our findings provide additional support for the assessment of the potential of dietary nitrate as a preventative strategy against atherogenesis in larger cohorts. This trial was registered at clinicaltrials.gov as NCT01493752.

Plasma levels of cytokines and chemokines and the risk of mortality in HIV-infected individuals: a case-control analysis nested in a large clinical trial

BACKGROUND

All-cause mortality and serious non-AIDS events (SNAEs) in individuals with HIV-1 infection receiving antiretroviral therapy are associated with increased production of interleukin-6 which appears to be driven by monocyte/macrophage activation. Plasma levels of other cytokines or chemokines associated with immune activation might also be biomarkers of an increased risk of mortality and/or SNAEs.

METHODS

Baseline plasma samples from 142 participants enrolled into the Strategies for Management of Antiretroviral Therapy study, who subsequently died, and 284 matched controls, were assayed for levels of 15 cytokines and chemokines. Cytokine and chemokine levels were analysed individually and when grouped according to function (innate/proinflammatory response, cell trafficking and cell activation/proliferation) for their association with the risk of subsequent death.

RESULTS

Higher plasma levels of proinflammatory cytokines (interleukin-6 and tumour necrosis factor-α) were associated with an increased risk of all-cause mortality but in analyses adjusted for potential confounders, only the association with interleukin-6 persisted. Increased plasma levels of the chemokine CXCL8 were also associated with all-cause mortality independently of hepatitis C virus status but not when analyses were adjusted for all confounders. In contrast, higher plasma levels of cytokines mediating cell activation/proliferation were not associated with a higher mortality risk and exhibited a weak protective effect when analysed as a group.

CONCLUSION

Whereas plasma levels of interleukin-6 are the most informative biomarker of cytokine dysregulation associated with all-cause mortality in individuals with HIV-1 infection, assessment of plasma levels of CXCL8 might provide information about causes of mortality and possibly SNAEs.

Comparative study of the effect of rivaroxaban and fondaparinux on monocyte's coagulant activity and cytokine release

OBJECTIVES

Tissue factor (TF) exposed on activated monocytes and macrophages is involved in thrombosis through activation of factor X and cytokine release, responsible for inflammation and thrombosis. We investigated the effect of two anti-factor Xa drugs: rivaroxaban, a direct anti-Xa inhibitor, and fondaparinux, an antithrombin dependent anti-Xa inhibitor, on monocyte/macrophage procoagulant activity and cytokine release.

METHODS

Rivaroxaban and fondaparinux were tested at pharmacological concentrations on LPS-activated monocytes and on THP-1 cells, a human monocytic cell line, to assess 1) TF expression by flow cytometry 2) prothrombinase activity by its coagulant activity and 3) cytokine release in cell supernatants by antibody based cytokine array and ELISA for IL-8 and TNFα.

RESULTS AND CONCLUSION

Rivaroxaban and fondaparinux did not modify TF expression level on activated cells. In contrast procoagulant activity associated to monocytes and macrophages was dose dependently inhibited by rivaroxaban, but not significantly by fondaparinux. These results could explain why patients undergoing major orthopedic surgery with rivaroxaban prophylaxis were able to achieve significant reductions in venous thromboembolism, compared with drugs commonly used, i.e. fondaparinux and low molecular weight heparin. In addition, rivaroxaban and fondaparinux suppressed some chemokine secretion produced by activated macrophages. This may also contribute to their antithrombotic effect in clinic.

MicroRNA-34a Induces Vascular Smooth Muscle Cells Senescence by SIRT1 Downregulation and Promotes the Expression of Age-Associated Pro-inflammatory Secretory Factors

Arterial aging is a major risk factor for the occurrence of cardiovascular diseases. The aged artery is characterized by endothelial dysfunction and vascular smooth muscle cells altered physiology together with low-grade chronic inflammation. MicroRNA-34a (miR-34a) has been recently implicated in cardiac, endothelial, and endothelial progenitor cell senescence; however, its contribution to aging-associated vascular smooth muscle cells phenotype has not been explored so far. We found that miR-34a was highly expressed in aortas isolated from old mice. Moreover, its well-known target, the longevity-associated protein SIRT1, was significantly downregulated during aging in both endothelial cells and vascular smooth muscle cells. Increased miR-34a as well as decreased SIRT1 expression was also observed in replicative-senescent human aortic smooth muscle cells. miR-34a overexpression in proliferative human aortic smooth muscle cells caused cell cycle arrest along with enhanced p21 protein levels and evidence of cell senescence. Furthermore, miR-34a ectopic expression induced pro-inflammatory senescence-associated secretory phenotype molecules. Finally, SIRT1 protein significantly decreased upon miR-34a overexpression and restoration of its levels rescued miR-34a-dependent human aortic smooth muscle cells senescence, but not senescence-associated secretory phenotype factors upregulation. Taken together, our findings suggest that aging-associated increase of miR-34a expression levels, by promoting vascular smooth muscle cells senescence and inflammation through SIRT1 downregulation and senescence-associated secretory phenotype factors induction, respectively, may lead to arterial dysfunctions.

TNF-α induces CXCL1 chemokine expression and release in human vascular endothelial cells in vitro via two distinct signaling pathways

AIM

Chemokines usually direct the movement of circulating leukocytes to sites of inflammation or injury. CXCL1/GRO-α has been shown to be upregulated in atherosclerotic lesions and various cancers. The aim of this study was to investigate the mechanisms underlying the TNF-α-induced release of CXCL1 from human vascular endothelial cells in vitro.

METHODS

Human umbilical vein endothelial cells (HUVECs) were treated with different proinflam-matory mediators and growth factors. CXCL1 expression and secretion were determined using RT-PCR and ELISA, respectively. TNF-α-induced cell signaling was assayed with Western blotting. Cell viability/growth was determined using MTT assay. Monocyte migration was measured with transwell migration assay.

RESULTS

Among the 17 mediators and growth factors tested, TNF-α, LPS and thrombin induced marked increase in CXCL1 release from HUVEC cells. TNF-α (2, 5 ng/mL) induced CXCL1 release and mRNA expression in the cells in concentration- and time-dependent manners. TNF-α (5 ng/mL) caused activation of JNK, p38 MAPK, PI3K and Akt, whereas pretreatment with JNK inhibitor (SP600125), p38 MAPK inhibitor (SB202190) or PI-3K inhibitor (LY294002) significantly suppressed TNF-α-induced CXCL1 release from the cells. But only SP600125 significantly reduced TNF-α-induced CXCL1 mRNA expression in the cells. Moreover, dexamethasone (up to 500 nmol/L) failed to affect TNF-α-induced CXCL1 release from the cells. In functional studies, recombinant CXCL1 enhanced HUVEC proliferation, and both recombinant CXCL1 and TNF-α-induced CXCL1 from HUVECs attracted human monocyte migration.

CONCLUSION

TNF-α stimulates CXCL1 release from human ECs through JNK-mediated CXCL1 mRNA expression and p38 MAPK- and PI-3K-mediated CXCL1 secretory processes.

Phenotypic analysis of chemokine-driven actin reorganization in primary human neutrophils

The chemokine-driven activation of CXC-type chemokine receptors 1/2 (CXCR1/2) and the subsequent reorganization of the neutrophilic actin are early key events in the induction of neutrophil migration toward centers of inflammation. In this study, an image analysis algorithm was developed to detect subtle chemokine-induced changes in the actin cytoskeleton of primary human neutrophils. By this means, a discrete early step of neutrophil activation was dissected that could be initiated by concentrations of growth-related oncogen α (Gro-α) or interleukin-8 (IL-8) just above their resting-state plasma levels. The associated half-maximal effective concentration (EC50) values for Gro-α and IL-8 of 8 and 22 pM, respectively, are between two and three orders of magnitude below the so-far reported EC50 values of these chemokines for the induction of neutrophilic calcium release, integrin expression, degranulation, and receptor internalization. Sch527123, a known inhibitor of CXCR2 (KD=49 pM) and with a lower potency/affinity also of CXCR1 (KD=3.9 nM), antagonized actin remodeling with half-maximal inhibitory concentration (IC50) values of 400 pM for the CXCR2-specific agonist Gro-α and of 36 nM for the CXCR1/2-promiscuous agonist IL-8. This observation indicates that the here-described early step of chemokine-driven actin reorganization is modulated by both CXCR1 and CXCR2. Thus, the imaging-based assay format, as developed in this work, may be employed in a phenotypic screening campaign to identify inhibitors of an early step in CXCR1/2-induced neutrophilic chemotaxis.

Increased levels of CCR7 ligands in carotid atherosclerosis: different effects in macrophages and smooth muscle cells

AIMS

The homeostatic chemokines, CCL19 and CCL21 and their receptor CCR7, have recently been linked to atherogenesis. We investigated the expression of CCL19/CCL21/CCR7 in carotid atherosclerosis as well as the ability of these chemokines to modulate lipid accumulation in macrophages and vascular smooth muscle cell (SMC) phenotype.

METHODS AND RESULTS

Our major findings were: (i) patients with carotid atherosclerosis (n = 158) had increased plasma levels of CCL21, but not of CCL19, compared with controls (n = 20), with particularly high levels in symptomatic (n = 99) when compared with asymptomatic (n = 59) disease. (ii) Carotid plaques showed markedly increased mRNA levels of CCL21 and CCL19 in symptomatic (n = 14) when compared with asymptomatic (n = 7) patients, with CCR7 localized to macrophages and vascular SMC (immunohistochemistry). (iii) In vitro, CCL21, but not CCL19, increased the binding of modified LDL and promoted lipid accumulation in THP-1 macrophages. (iv) CCL19, but not CCL21, increased proliferation and release and activity of matrix metalloproteinase (MMP) 1 in vascular SMC. (v) The differential effects of CCL19 and CCL21 in macrophages and SMC seem to be attributable to divergent signalling pathways, with CCL19-mediated activation of AKT in SMC- and CCL21-mediated activation of extracellular signal-regulated kinase 1/2 in macrophages.

CONCLUSION

CCL19 and CCL21 are up-regulated in carotid atherosclerosis. The ability of CCL21 to promote lipid accumulation in macrophages and of CCL19 to induce proliferation and MMP-1 expression in vascular SMC could contribute to their pro-atherogenic potential.

Plasma NOV/CCN3 levels are closely associated with obesity in patients with metabolic disorders

OBJECTIVE

Evidence points to a founder of the multifunctional CCN family, NOV/CCN3, as a circulating molecule involved in cardiac development, vascular homeostasis and inflammation. No data are available on the relationship between plasma NOV/CCN3 levels and cardiovascular risk factors in humans. This study investigated the possible relationship between plasma NOV levels and cardiovascular risk factors in humans.

METHODS

NOV levels were measured in the plasma from 594 adults with a hyperlipidemia history and/or with lipid-lowering therapy and/or a body mass index (BMI) >30 kg/m(2). Correlations were measured between NOV plasma levels and various parameters, including BMI, fat mass, and plasma triglycerides, cholesterol, glucose, and C-reactive protein. NOV expression was also evaluated in adipose tissue from obese patients and rodents and in primary cultures of adipocytes and macrophages.

RESULTS

After full multivariate adjustment, we detected a strong positive correlation between plasma NOV and BMI (r = 0.36 p<0.0001) and fat mass (r = 0.33 p<0.0005). According to quintiles, this relationship appeared to be linear. NOV levels were also positively correlated with C-reactive protein but not with total cholesterol, LDL-C or blood glucose. In patients with drastic weight loss induced by Roux-en-Y bariatric surgery, circulating NOV levels decreased by 28% (p<0.02) and 48% (p<0.0001) after 3 and 6 months, respectively, following surgery. In adipose tissue from obese patients, and in human primary cultures NOV protein was detected in adipocytes and macrophages. In mice fed a high fat diet NOV plasma levels and its expression in adipose tissue were also significantly increased compared to controls fed a standard diet.

CONCLUSION

Our results strongly suggest that in obese humans and mice plasma NOV levels positively correlated with NOV expression in adipose tissue, and support a possible contribution of NOV to obesity-related inflammation.

Roles of chemokine ligand-2 (CXCL2) and neutrophils in influencing endothelial cell function and inflammation of human adipose tissue

The hypertrophied white adipose tissue (WAT) during human obesity produces inflammatory mediators, including cytokines (IL-6 and TNFα) and chemokines ([C-C motif] chemokine ligand 2 and IL-8). These inflammatory factors are preferentially produced by the nonadipose cells, particularly the adipose tissue infiltrating macrophages. We identified the chemokine (C-X-C motif) ligand 2 (CXCL2) by a transcriptomic approach. Because CXCL2 could represent a WAT-produced chemokine, we explored its role in obesity-associated inflammation. CXCL2 levels in serum and mRNA in WAT were higher in obese subjects compared with lean ones. CXCL2 secretions were higher in sc and visceral (vis) WAT from obese compared with lean subjects. In vis WAT, CXCL2 mRNA expression was higher in macrophages compared with other WAT cells and positively correlated with the inflammatory macrophage markers TNFα and IL-6. CXCL2 triggered the in vitro adhesion of the neutrophils, its selective cell targets, to endothelial cells (ECs) of vis WAT (vis WAT-ECs). Immunohistological analysis indicated that activated neutrophils were adherent to the endothelium of vis WAT from human obese subjects. Blood neutrophils from obese subjects released high levels of proinflammatory mediators (IL-8, chemokine motif ligand 2 [CCL2], matrix metalloproteinase [MMP] 9, and myeloperoxidase [MPO]). Visceral WAT-ECs, treated by neutrophil-conditioned media prepared from obese subjects, displayed an increase of the expression of inflammatory molecules associated with senescence and angiogenic capacities. To conclude, CXCL2, a WAT-produced chemokine being up-regulated in obesity, stimulates neutrophil adhesion to vis WAT-ECs. Activated neutrophils in obesity may influence vis WAT-ECs functions and contribute to WAT inflammation.

Regulation of atherogenesis by chemokines and chemokine receptors

Atherosclerosis is a chronic inflammatory and metabolic disorder affecting large- and medium-sized arteries, and the leading cause of mortality worldwide. The pathogenesis of atherosclerosis involves accumulation of lipids and leukocytes in the intima of blood vessel walls creating plaque. How leukocytes accumulate in plaque remains poorly understood; however, chemokines acting at specific G protein-coupled receptors appear to be important. Studies using knockout mice suggest that chemokine receptor signaling may either promote or inhibit atherogenesis, depending on the receptor. These proof of concept studies have spurred efforts to develop drugs targeting the chemokine system in atherosclerosis, and several have shown beneficial effects in animal models. This study will review key discoveries in basic and translational research in this area.

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.

A potential role of the GRO-α/CXCR2 system in Sjögren's syndrome: regulatory effects of pro-inflammatory cytokines

Chemokines, small pro-inflammatory cytokines, are involved in migration of inflammatory cells in inflamed tissues and recent studies established their role in angiogenesis, hematopoiesis, cancer and autoimmune conditions. Growth related oncogene-alpha (GRO-α), a member of the CXC chemokine family, and its receptor CXCR2 are involved in the inflammatory processes. Since there is no previous report that supports a possible role of GRO-α/CXCR2 receptor complex during inflammation and neovascularization existing in the autoimmune disease Sjögren's syndrome (SS), in this study, we examined CXCR2 and its ligand GRO-α expression in SS tissues. Immunohistochemistry revealed that GRO-α and its receptor CXCR2 were expressed at high levels in diseased tissues compared to healthy controls. In addition, human salivary gland epithelial cells (SGEC) cultures were submitted to a pro-inflammatory microenvironment using cytokines IL-6 and TNF-α in order to demonstrate that CXCR2 may change its initial expression pattern to another under inflammatory condition. The data show an increased expression of CXCR2 depending on the inflammatory cytokine used in culture in a time-dependent manner. Furthermore, silencing of the pro-angiogenic chemokine GRO-α is proportionally correlated with decreased expression of CXCR2 in pro-inflammatory cytokine-stimulated SGEC indicating the GRO-α/CXCR2 complex as a novel therapeutic target for the chronic inflammatory disease Sjögren's syndrome.

Statins affect the presentation of endothelial chemokines by targeting to multivesicular bodies

Background

In addition to lowering cholesterol, statins are thought to beneficially modulate inflammation. Several chemokines including CXCL1/growth-related oncogene (GRO)-α, CXCL8/interleukin (IL)-8 and CCL2/monocyte chemoattractant protein (MCP)-1 are important in the pathogenesis of atherosclerosis and can be influenced by statin-treatment. Recently, we observed that atorvastatin­treatment alters the intracellular content and subcellular distribution of GRO-α in cultured human umbilical vein endothelial cells (HUVECs). The objective of this study was to investigate the mechanisms involved in this phenomenon.

Methodology/ Principal Findings

The effect of atorvastatin on secretion levels and subcellular distribution of GRO-α, IL-8 and MCP-1 in HUVECs activated by interleukin (IL)-1β were evaluated by ELISA, confocal microscopy and immunoelectron microscopy. Atorvastatin increased the intracellular contents of GRO-α, IL-8, and MCP-1 and induced colocalization with E-selectin in multivesicular bodies. This effect was prevented by adding the isoprenylation substrate GGPP, but not the cholesterol precursor squalene, indicating that atorvastatin exerts these effects by inhibiting isoprenylation rather than depleting the cells of cholesterol.

Conclusions/ Significance

Atorvastatin targets inflammatory chemokines to the endocytic pathway and multivesicular bodies and may contribute to explain the anti-inflammatory effect of statins at the level of endothelial cell function.

Social disruption stress increases IL-6 levels and accelerates atherosclerosis in ApoE-/- mice

INTRODUCTION

We have previously shown that different forms of stress have distinctive effects on atherogenesis in mice. We showed that social stress increase atherosclerosis in ApoE(-/-) mice, while more physical forms of stress do not. Here we evaluated the effect of social disruption (SDR) stress on atherogenesis and evaluated cytokine release after SDR-stress and five more physical stressors.

METHODS

Male ApoE(-/-) mice were exposed to SDR-stress during 12 weeks, and atherosclerotic plaque area was assessed in aorta, aortic root and innominate artery. Further, male C57BL/6 mice were exposed to SDR-stress or five physical stressors, and cytokine and corticosterone levels were analyzed in plasma/serum samples immediately after stress.

RESULTS

We found a correlation between the level of SDR-stress and atherosclerotic plaque area in aorta and a numerical increased plaque area in aortic root. SDR stress did not affect histological features of plaque composition. However, SDR-stress increased levels of corticosterone, IL-6 and CXCL1. Plasma corticosterone increased for all five physical stressors, but IL-6 and CXCL1 only increased in the group exposed to restraint combined with rat odor.

CONCLUSIONS

These findings suggest that SDR-stress is indeed atherogenic, in contrast to our previous results using the physical stressors. A possible explanation to this difference is that SDR-stress, but not physical stressors, leads to release of the pro-inflammatory cytokines IL-6 and CXCL1.

Pattern specification and immune response transcriptional signatures of pericardial and subcutaneous adipose tissue

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in the United States. Recent studies suggest that pericardial adipose tissue (PCAT) secretes inflammatory factors that contribute to the development of CVD. To better characterize the role of PCAT in the pathogenesis of disease, we performed a large-scale unbiased analysis of the transcriptional differences between PCAT and subcutaneous adipose tissue, analysing 53 microarrays across 19 individuals. As it was unknown whether PCAT-secreted factors are produced by adipocytes or cells in the supporting stromal fraction, we also sought to identify differentially expressed genes in isolated pericardial adipocytes vs. isolated subcutaneous adipocytes. Using microarray analysis, we found that: 1) pericardial adipose tissue and isolated pericardial adipocytes both overexpress atherosclerosis-promoting chemokines and 2) pericardial and subcutaneous fat depots, as well as isolated pericardial adipocytes and subcutaneous adipocytes, express specific patterns of homeobox genes. In contrast, a core set of lipid processing genes showed no significant overlap with differentially expressed transcripts. These depot-specific homeobox signatures and transcriptional profiles strongly suggest different functional roles for the pericardial and subcutaneous adipose depots. Further characterization of these inter-depot differences should be a research priority.

Use of human embryonic stem cell derived-mesenchymal cells for cardiac repair

Human mesenchymal stem cells (hMSC) have proven beneficial in the repair and preservation of infarcted myocardium. Unfortunately, MSCs represent a small portion of the bone marrow and require ex vivo expansion. To further advance the clinical usefulness of cellular cardiomyoplasty, derivation of "MSC-like" cells that can be made available "off-the-shelf" are desirable. Recently, human embryonic stem cell-derived mesenchymal cells (hESC-MC) were described. We investigated the efficacy of hESC-MC for cardiac repair after myocardial infarction (MI) compared to hMSC. Because of increased efficacy of cell delivery, cells were embedded into collagen patches and delivered to infarcted myocardium. Culture of hMSC and hESC-MCs in collagen patches did not induce differentiation or significant loss in viability. Transplantation of hMSC and hES-MC patches onto infarcted myocardium of athymic nude rats prevented adverse changes in infarct wall thickness and fractional area change compared to a non-viable patch control. Hemodynamic assessment showed that hMSCs and hES-MC patch application improved end diastolic pressure equivalently. There were no changes in systolic function. hES-MC and hMSC construct application enhanced neovessel formation compared to a non-viable control, and each cell type had similar efficacy in stimulating endothelial cell growth in vitro. In summary, the use of hES-MC provides similar efficacy for cellular cardiomyoplasty as compared to hMSC and may be considered a suitable alternative for cell therapy.

Serglycin is a major proteoglycan in polarized human endothelial cells and is implicated in the secretion of the chemokine GROalpha/CXCL1

Proteoglycan (PG) expression was studied in primary human umbilical vein endothelial cells (HUVEC). RT-PCR analyses showed that the expression of the PG serglycin core protein was much higher than that of the extracellular matrix PG decorin and the cell surface PG syndecan-1. PG biosynthesis was further studied by biosynthetic [(35)S]sulfate labeling of polarized HUVEC. Interestingly, a major part of (35)S-PGs was secreted to the apical medium. A large portion of these PGs was trypsin-resistant, a typical feature of serglycin. The trypsin-resistant PGs were mainly of the chondroitin/dermatan sulfate type but also contained a minor heparan sulfate component. Secreted serglycin was identified by immunoprecipitation as a PG with a core protein of ∼30 kDa. Serglycin was furthermore shown to be present in perinuclear regions and in two distinct types of vesicles throughout the cytoplasm using immunocytochemistry. To search for possible serglycin partner molecules, HUVEC were stained for the chemokine growth-related oncogene α (GROα/CXCL1). Co-localization with serglycin could be demonstrated, although not in all vesicles. Serglycin did not show overt co-localization with tissue-type plasminogen activator-positive vesicles. When PG biosynthesis was abrogated using benzyl-β-D-xyloside, serglycin secretion was decreased, and the number of vesicles with co-localized serglycin and GROα was reduced. The level of GROα in the apical medium was also reduced after xyloside treatment. Together, these findings indicate that serglycin is a major PG in human endothelial cells, mainly secreted to the apical medium and implicated in chemokine secretion.

Associations of four circulating chemokines with multiple atherosclerosis phenotypes in a large population-based sample: results from the dallas heart study

Specific chemokines contribute to vascular inflammation and may be useful biomarkers to detect atherosclerosis. The chemokines CXCL1 and CCL11 have previously been studied in animal or human models of atherosclerosis, while CXCL2 and CCL23 have not. Among 2,454 subjects enrolled in the Dallas Heart Study, a multi-ethnic population-based sample, we measured plasma CCL11, CCL23, CXCL1, and CXCL2, and associated levels with coronary artery calcium (CAC) by computed tomography, and aortic wall thickness, plaque burden, and compliance by magnetic resonance imaging. Elevated chemokine levels were defined as greater than or equal to the median for CCL11 and CCL23 and greater than or equal to the upper detection limit for CXCL1 and CXCL2. Elevated CCL23 (P < 0.01) and CXCL1 (P = 0.01), but not CCL11 and CXCL2, associated with CAC in univariable analyses. After adjustment for traditional risk factors, elevated CCL23 remained associated with CAC (OR 1.3, 95% CI 1.0-1.7; P = 0.02), while the association with CXCL1 was modestly attenuated (OR 1.4, 95% CI 1.0-2.1; P = 0.06). CCL23 also associated with aortic wall thickness, plaque, and compliance in univariable analyses (P < 0.05 for each), but these associations were attenuated after multivariable adjustment. The novel chemotactic protein, CCL23, which has not been previously studied in atherosclerosis, is independently associated with coronary atherosclerosis, suggesting that this chemokine merits further study in animal and human models.

Effect of obesity on growth-related oncogene factor-alpha, thrombopoietin, and tissue inhibitor metalloproteinase-1 serum levels

We have recently identified several adipokines as oversecreted by omental adipose tissue (AT) of obese subjects: two chemokines (growth-related oncogene factor-alpha (GRO-alpha), macrophage inflammatory protein-1 beta (MIP-1 beta)), a tissue inhibitor of metalloproteinases-1 (TIMP-1), an interleukin-7 (IL-7) and a megakaryocytic growth-factor (thrombopoietin (TPO)). These adipokines are involved in insulin resistance and atherosclerosis. The objectives of this study were to determine whether the circulating levels of these adipokines were increased in obesity and to identify the responsible factors. A cross-sectional study including 32 lean (BMI (kg/m(2)) <25), 15 overweight (BMI: 25-29.9), 11 obese (BMI: 30-39.9), and 17 severely obese (BMI >40) age-matched women was carried out. Serum adipokine levels, insulin sensitivity, and substrate oxidation were measured by ELISA, euglycemic-hyperinsulinemic clamp, and indirect calorimetry, respectively. Circulating levels of GRO-alpha, TPO, and TIMP-1 were higher in obese and/or severely obese women than in lean ones (+30, 55, and 20%, respectively). Serum levels of these adipokines positively correlated with insulinemia or glycemia, and negatively with insulin sensitivity. TIMP-1 also positively correlated with blood pressure, and TPO with triglyceride levels. Multiple regression analysis showed that fat mass per se was an independent determinant of GRO-alpha, TPO, and TIMP-1 levels, suggesting that hypertrophied adipocytes and recruited macrophages in expanded AT mainly contribute to this hyperadipokinemia. Insulinemia, glycemia and resistance of glucose oxidation to insulin were additional predictors for TPO. Circulating GRO-alpha, TPO, and TIMP-1 levels are increased in obesity. This may be partially due to augmented adiposity per se and to hyperinsulinemia/insulin resistance. These high systemic levels may in turn worsen/promote insulin resistance and cardiovascular disease.

The role of chemokines in recruitment of immune cells to the artery wall and adipose tissue

The role of the immune system is to recognize pathogens, tumor cells or dead cells and to react with a very specific and localized response. By taking advantage of a highly sophisticated system of chemokines and chemokine receptors, leukocytes such as neutrophils, macrophages, and T-lymphocytes are targeted to the precise location of inflammation. While this is a beneficial process for acute infection and inflammation, recruitment of immune cells to sites of chronic inflammation can be detrimental. It is becoming clear that these inflammatory cells play a significant role in the initiation and progression of metabolic disorders such as atherosclerosis and insulin resistance by infiltrating the artery wall and adipose tissue (AT), respectively. Data from human studies indicate that elevated plasma levels of chemokines are correlated with these metabolic diseases. Recruitment of macrophages to the artery wall is well known to be one of the first steps in early atherosclerotic lesion formation. Likewise, recruitment of macrophages to AT is thought to contribute to insulin resistance associated with obesity. Based on this knowledge, much recent work in these areas has focused on the role of chemokines in attracting immune cells (monocytes/macrophages in particular) to these 2 sites. Thus, understanding the potential for chemokines to contribute to metabolic disease can help direct studies of chemokines as therapeutic targets. In this article, we will review current literature regarding the role of chemokines in atherosclerosis and obesity-related insulin resistance. We will focus on novel work showing that chemokine secretion from endothelial cells, platelets, and adipocytes can contribute to immune cell recruitment, with a diagram showing the time course of chemokine expression and leukocyte recruitment to AT. We will also highlight a few of the less-commonly known chemokine-chemokine receptor pairs. Finally, we will discuss the potential for chemokines as therapeutic targets for treatment of atherosclerosis and insulin resistance.

LPS induces GROalpha chemokine production via NF-kappaB in oral fibroblasts

OBJECTIVE AND DESIGN

Chemotaxis of neutrophils from blood to the inflammation process plays an important role in development of periodontal inflammation. The novel chemokine GROalpha, also named CXCL1, is a strong chemoattractant for neutrophils. Data on production and regulation of GROalpha by oral fibroblasts have not previously been presented.

MATERIALS AND METHODS

GROalpha mRNA and protein levels were determined in human periodontal ligament cells and mouse gingival fibroblasts by quantitative real-time PCR and ELISA.

RESULTS

We disclose that both human periodontal ligament cells and mouse gingival fibroblasts produce GROalpha in response to LPS stimulation. Stimulation with LPS for 24 h increased both mRNA for GROalpha and GROalpha protein. The steroid hormone estrogen had no effect on LPS-induced GROalpha mRNA expression. Treatment with the glucocorticoid dexamethasone attenuated LPS-induced GROalpha production, and the NF-kappaB blocker MG 132 fully prevented LPS-induced GROalpha.

CONCLUSIONS

Oral fibroblasts respond to LPS stimulation by increasing GROalpha production via the transcription factor NF-kappaB, suggesting that this mechanism may be involved in development of periodontal inflammation.

Ambivalence of progenitor cells in vascular repair and plaque stability

PURPOSE OF REVIEW

To discuss crucial cues (chemokines, adhesion molecules and pharmacological means) that guide and control the context-specific mobilization, recruitment and fate of circulating progenitor cells in arterial repair and plaque stability.

RECENT FINDINGS

The mobilization and recruitment of bone marrow derived or resident progenitor cells giving rise to smooth muscle cells have been implicated in accelerated forms of primary plaque formation and neointimal hyperplasia after arterial injury. By contrast, convincing evidence has emerged that the arterial homing of endothelial progenitor cells contributes to endothelial recovery and thereby limits neointimal growth after endothelial denudation. In the chronic context of primary atherosclerosis, plaque progression and destabilization, a more complex picture has become apparent. Clinically, the number and function of endothelial progenitor cells have been linked with an improved endothelial function or regeneration and have been frequently inversely correlated with cardiovascular risk (factors). In animal models, however, the injection of bone marrow cells or endothelial progenitor cells, as well as the application of stem-cell mobilizing factors, have been associated with an exacerbation of atherosclerosis and unstable plaque phenotype, whereas the contribution of smooth muscle progenitors to primary atherosclerosis appears to be more confined to supporting plaque stability.

SUMMARY

Considering the balance between distinct circulating vascular progenitor cells and identifying mechanisms for selective control of their mobilization and homing appears crucial to improve prediction and to directly modulate endogenous vascular remodeling processes.