Monocyte chemoattractant protein-1 but not tumor necrosis factor-alpha is correlated with monocyte infiltration in mouse lipid lesions

Factors associated with early-onset intracranial aneurysms in patients with autosomal dominant polycystic kidney disease

BACKGROUND

Recently, the importance of attribute-based medicine has been emphasized. The effects of early-onset intracranial aneurysms on patients can be significant and long-lasting. Herein, we compared the factors associated with intracranial aneurysms in patients with autosomal dominant polycystic kidney disease (ADPKD) according to age categories (≥ 50 years, < 50 years).

METHODS

We included 519 ADPKD patients, with a median age of 44 years, estimated glomerular filtration rate of 54.5 mL/min/1.73 m2, and total follow-up duration of 3104 patient-years. Logistic regression analyses were performed to determine factors associated with intracranial aneurysms.

RESULTS

Regarding the presence of intracranial aneurysm, significant interactions were identified between the age category (age ≥ 50 years), female sex (P = 0.0027 for the interaction) and hypertension (P = 0.0074 for the interaction). Female sex and hypertension were associated with intracranial aneurysm risk factors only in patients aged ≥ 50 years. The presence of intracranial aneurysm was significantly associated with chronic kidney disease (CKD) stages 4-5 (odds ratio [OR] = 3.87, P = 0.0007) and family history of intracranial aneurysm or subarachnoid hemorrhage (OR = 2.30, P = 0.0217) in patients aged < 50 years. For patients aged ≥ 50 years, in addition to the abovementioned factors [OR = 2.38, P = 0.0355 for CKD stages 4-5; OR = 3.49, P = 0.0094 for family history of intracranial aneurysm or subarachnoid hemorrhage], female sex (OR = 4.51, P = 0.0005), and hypertension (OR = 5.89, P = 0.0012) were also associated with intracranial aneurysm.

CONCLUSION

Kidney dysfunction and family history of intracranial aneurysm or subarachnoid hemorrhage are risk factors for early-onset intracranial aneurysm. Patients aged < 50 years with a family history of intracranial aneurysm or subarachnoid hemorrhage or with CKD stages 4-5 may be at an increased risk of early-onset intracranial aneurysm.

β-Aminoisobutyric Acid Suppresses Atherosclerosis in Apolipoprotein E-Knockout Mice

Endurance exercise training has been shown to induce peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in skeletal muscle. We recently reported that skeletal muscle-specific PGC-1α overexpression suppressed atherosclerosis in apolipoprotein E-knockout (ApoE^-/-) mice. β-Aminoisobutyric acid (BAIBA) is a PGC-1α-dependent myokine secreted from myocytes that affects multiple organs. We have also reported that BAIBA suppresses tumor necrosis factor-alpha-induced vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) gene expression in endothelial cells. In the present study, we hypothesized that BAIBA suppresses atherosclerosis progression, and tested that hypothesis with ApoE^-/- mice. The mice were administered water containing BAIBA for 14 weeks, and were then sacrificed at 20 weeks of age. Atherosclerotic plaque area, plasma BAIBA concentration, and plasma lipoprotein profiles were assessed. Immunohistochemical analyses of the plaque were performed to assess VCAM-1 and MCP-1 protein expression levels and macrophage infiltration. The results showed that BAIBA administration decreased atherosclerosis plaque area by 30%, concomitant with the elevation of plasma BAIBA levels. On the other hand, plasma lipoprotein profiles were not changed by the administration. Immunohistochemical analyses indicated reductions in VCAM-1, MCP-1, and Mac-2 protein expression levels in the plaque. These results suggest that BAIBA administration suppresses atherosclerosis progression without changing plasma lipoprotein profiles. We propose that the mechanisms of this suppression are reductions in both VCAM-1 and MCP-1 expression as well as macrophage infiltration into the plaque.

Inhibition of human cytomegalovirus replication by tricin is associated with depressed CCL2 expression

We previously reported that treatment with tricin (4',5,7-trihydroxy-3',5'-dimethoxyflavone) after human cytomegalovirus (HCMV) infection significantly suppressed both infectious virion production and HCMV replication in human embryonic lung fibroblast (HEL) cells. Moreover, we recently demonstrated that HCMV infection can increase the expression of CC-motif ligand 2 (CCL2/MCP-1) and of CCR2, a CCL2-specific receptor, effects that can in turn enhance HCMV infection and replication. Hence, we here examined whether the CCL2-CCR2 axis is involved in the anti-HCMV effects of tricin in HEL cells. Tricin exposure yielded dose-dependent decreases in the accumulation of transcripts for the HCMV immediate early gene and the DNA polymerase gene in HCMV-infected cells, along with decreased production of infectious HCMV. Concomitantly, tricin caused dose-dependent attenuation of HCMV infection-induced up-regulation of expression of CCL2 and CCR2 mRNAs and of CCL2 protein. Moreover, CCL2 reversed tricin-mediated inhibition of HCMV virion production in a dose-dependent manner. Thus, tricin appears to exert anti-HCMV activity by depressing CCL2 expression.

Evidence that periodontal treatment improves biomarkers and CVD outcomes

AIM

The aim of this review was to critically appraise the evidence on the impact of periodontal treatment of cardiovascular diseases (CVDs) biomarkers and outcomes.

METHODS

A systematic search was performed in Cinhal, Cochrane, Embase and Medline for relevant articles up to July 2012. Duplicate screening and reference hand searching were performed. Data were then summarized and evidence graded in tables.

RESULTS

The search resulted in: (a) no evidence on the effects of periodontal therapy on subclinical atherosclerosis, serum levels of CD40 ligand, serum amyloid A and monocyte chemoattractant protein-1, (b) limited evidence on the effects of periodontal therapy on arterial blood pressure, leucocyte counts, fibrinogen, tissue necrosis factor-α, sE-selectin, von Willebrand factors, d-dimers, matrix metalloproteinases, oxidative stress and CVD events, and (c) moderate evidence suggesting a negligible effect of periodontal therapy in reducing interleukin-6 and lipids levels, whilst a positive effect in reducing serum C-reactive protein levels and improving endothelial function.

CONCLUSIONS

Periodontal therapy triggers a short-term inflammatory response followed by (a) a progressive and consistent reduction of systemic inflammation and (b) an improvement in endothelial function. There is however limited evidence that these acute and chronic changes will either increase or reduce CVD burden of individuals suffering from periodontitis in the long term.

Evidence that periodontal treatment improves biomarkers and CVD outcomes

AIM

The aim of this review was to critically appraise the evidence on the impact of periodontal treatment of cardiovascular diseases (CVDs) biomarkers and outcomes.

METHODS

A systematic search was performed in Cinhal, Cochrane, Embase and Medline for relevant articles up to July 2012. Duplicate screening and reference hand searching were performed. Data were then summarized and evidence graded in tables.

RESULTS

The search resulted in: (a) no evidence on the effects of periodontal therapy on subclinical atherosclerosis, serum levels of CD40 ligand, serum amyloid A and monocyte chemoattractant protein-1, (b) limited evidence on the effects of periodontal therapy on arterial blood pressure, leucocyte counts, fibrinogen, tissue necrosis factor-a, sE-selectin, von Willebrand factors, d-dimers, matrix metalloproteinases, oxidative stress and CVD events, and (c) moderate evidence suggesting a negligible effect of periodontal therapy in reducing interleukin-6 and lipids levels, whilst a positive effect in reducing serum C-reactive protein levels and improving endothelial function.

CONCLUSIONS

Periodontal therapy triggers a short-term inflammatory response followed by (a) a progressive and consistent reduction of systemic inflammation and (b) an improvement in endothelial function. There is however limited evidence that these acute and chronic changes will either increase or reduce CVD burden of individuals suffering from periodontitis in the long term.

Immunohistochemical analysis of paraoxonases and chemokines in arteries of patients with peripheral artery disease

Oxidative damage to lipids and lipoproteins is implicated in the development of atherosclerotic vascular diseases, including peripheral artery disease (PAD). The paraoxonases (PON) are a group of antioxidant enzymes, termed PON1, PON2, and PON3 that protect lipoproteins and cells from peroxidation and, as such, may be involved in protection against the atherosclerosis process. PON1 inhibits the production of chemokine (C–C motif) ligand 2 (CCL2) in endothelial cells incubated with oxidized lipoproteins. PON1 and CCL2 are ubiquitously distributed in tissues, and this suggests a joint localization and combined systemic effect. The aim of the present study has been to analyze the quantitative immunohistochemical localization of PON1, PON3, CCL2 and CCL2 receptors in a series of patients with severe PAD. Portions of femoral and/or popliteal arteries from 66 patients with PAD were obtained during surgical procedures for infra-inguinal limb revascularization. We used eight normal arteries from donors as controls. PON1 and PON3, CCL2 and the chemokine-binding protein 2, and Duffy antigen/chemokine receptor, were increased in PAD patients. There were no significant changes in C–C chemokine receptor type 2. Our findings suggest that paraoxonases and chemokines play an important role in the development and progression of atherosclerosis in peripheral artery disease.

Effects of Calcium Fructoborate on Levels of C-Reactive Protein, Total Cholesterol, Low-Density Lipoprotein, Triglycerides, IL-1β, IL-6, and MCP-1: a Double-blind, Placebo-controlled Clinical Study

Calcium fructoborate (CFB) has been reported as supporting healthy inflammatory response. In this study, we assess the effects of CFB on blood parameters and proinflammatory cytokines in healthy subjects. This was a randomized, double-blinded, placebo-controlled trial. Participants received placebo or CFB at a dose of 112 mg/day (CFB-1) or 56 mg/day (CFB-2) for 30 days. Glucose, total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides (TG), C-reactive protein (CRP), homocysteine, interleukin 1 beta (IL-1β), IL-6, and monocyte chemoattractant protein-1 (MCP-1) were determined before and after supplementation. CFB-1 showed a reduction in blood levels of CRP by 31.3 % compared to baseline. CFB-1 and CFB-2 reduced LDL levels by 9.8 and 9.4 %, respectively. CFB-1 decreased blood homocysteine by 5.5 % compared with baseline, whereas CFB-2 did not have a significant effect. Blood levels of TG were reduced by 9.1 and 8.8 % for CFB-1 and CFB-2, respectively. Use of both CFB-1 and CFB-2 resulted in significantly reduced IL-6 levels, when compared within and between groups. IL-1β was reduced by 29.2 % in the CFB-1 group. Finally, CFB-1 and CFB-2 reduced MCP-1 by 31 and 26 %, respectively. Our data indicate that 30-day supplementation with 112 mg/day CFB (CFB-1) resulted in a significant reduction of LDL, TG, TC, IL-1β, IL-6, MCP-1, and CRP. HDL levels were increased, when compared to baseline and placebo. These results suggest that CFB might provide beneficial support to healthy cardiovascular systems by positively affecting these blood markers (ClinicalTrials.gov, ISRCTN90543844; May 24, 2012 ( http://www.controlled-trials.com/ISRCTN90543844 )).

Understanding the role of circulating chemokine (C-C motif) ligand 2 in patients with chronic ischemia threatening the lower extremities

The role of chemokine (C-C motif) ligand 2 (CCL2) in peripheral artery disease is unclear. We measured the difference between serum and plasma levels of CCL2 in patients with chronic ischemia threatening the lower extremities following the observation that atypical chemokine receptors in blood and tissue cells may prevent CCL2 from entering the circulation and consequently modulate its function of attracting monocytes to the site of lesion. To identify the influence of CCL2, we compared the patients' values to those in bio-banked samples from a control population. Further, we explored the association with the Asp42Gly polymorphism (rs12075) in Duffy antigen chemokine receptor; one of these atypical chemokine receptors. When possible, we evaluated in surgically excised normal and affected arteries the calcium burden as well as the expression of CCL2 and related receptors reflecting the inflammatory status. Our findings indicate that circulating CCL2 was significantly associated with the severity and presence of the disease (OR 0.966, 95% CI 0.944 to 0.988, p = 0.003). Circulating CCL2 was dependent on the rs12075 genotype (AA>AG>GG), which, probably, indicates a higher expression of chemokine receptor in the arteries of AA subjects. The associations with genetic variants and the over-expression of atypical chemokine receptors in diseased arteries may have potential implications and our data indicate that CCL2 may represent a previously unrecognized factor that needs to be considered in the screening of patients with risk factors for peripheral artery disease.

Aging exacerbates obesity-induced oxidative stress and inflammation in perivascular adipose tissue in mice: a paracrine mechanism contributing to vascular redox dysregulation and inflammation

Obesity in the elderly individuals is increasing at alarming rates and there is evidence suggesting that elderly individuals are more vulnerable to the deleterious cardiovascular effects of obesity than younger individuals. However, the specific mechanisms through which aging and obesity interact to promote the development of cardiovascular disease remain unclear. The present study was designed to test the hypothesis that aging exacerbates obesity-induced inflammation in perivascular adipose tissue, which contributes to increased vascular oxidative stress and inflammation in a paracrine manner. To test this hypothesis, we assessed changes in the secretome, reactive oxygen species production, and macrophage infiltration in periaortic adipose tissue of young (7 month old) and aged (24 month old) high-fat diet-fed obese C57BL/6 mice. High-fat diet-induced vascular reactive oxygen species generation significantly increased in aged mice, which was associated with exacerbation of endothelial dysfunction and vascular inflammation. In young animals, high-fat diet-induced obesity promoted oxidative stress in the perivascular adipose tissue, which was associated with a marked proinflammatory shift in the profile of secreted cytokines and chemokines. Aging exacerbated obesity-induced oxidative stress and inflammation and significantly increased macrophage infiltration in periaortic adipose tissue. Using cultured arteries isolated from young control mice, we found that inflammatory factors secreted from the perivascular fat tissue of obese aged mice promote significant prooxidative and proinflammatory phenotypic alterations in the vascular wall, mimicking the aging phenotype. Overall, our findings support an important role for localized perivascular adipose tissue inflammation in exacerbation of vascular oxidative stress and inflammation in aging, an effect that likely enhances the risk for development of cardiovascular diseases from obesity in the elderly individuals.

Curcumin inhibits ox-LDL-induced MCP-1 expression by suppressing the p38MAPK and NF-κB pathways in rat vascular smooth muscle cells

OBJECTIVE

This study was designed to identify the inhibitory effect of curcumin on ox-LDL-induced monocyte chemoattractant protein-1 (MCP-1) production and investigated whether the effects are mediated by mitogen-activated protein kinase (MAPK) and NF-κB pathways in rat vascular smooth muscle cells (VSMCs).

METHODS

The VSMCs cells were pretreated with curcumin, before stimulation with ox-LDL. The ox-LDL-induced MCP-1 expression was determined by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). Intracellular signaling was investigated by Western blot.

RESULTS

The concentrations of MCP-1 in cell supernatant and were upregulated by ox-LDL in a dose- and time-dependent manner. Additionally, curcumin decreased the expression of MCP-1 in a dose-dependent manner under treatment with ox-LDL (100 μg/ml). Signal transduction studies indicated that the ox-LDL-induced MCP-1 expression in VSMCs could be partly reversed by the inhibitor of p38 MAPK (SB203580) and NF-κB (BAY11-7082), whereas the ERK inhibitor (PD98059) and the JNK inhibitor (SP600125) had no effect. Western blot revealed that curcumin reduced ox-LDL- induced p38 MAPK phosphorylation and nuclear NF-κB p65 protein at the indicated concentration.

CONCLUSION

Curcumin suppresses ox-LDL-induced MCP-1 expression in VSMCs via the p38 MAPK and NF-κB pathways, which suggests that the anti-inflammatory effect of curcumin is related to the down-regulation of MCP-1 expression and offers a new theoretical basis in the anti-inflammatory effects of curcumin.

The development and the use of experimental animal models to study the underlying mechanisms of CA formation

Cerebral aneurysms (CAs) have a high prevalence and can cause a lethal subarachnoid hemorrhage. Currently, CAs can only be treated with invasive surgical procedures. To unravel the underlying mechanisms of CA formation and to develop new therapeutic drugs for CAs, animal models of CA have been established, modified, and analyzed. Experimental findings from these models have clarified some of the potential mechanisms of CA formation, especially the relationship between hemodynamic stress and chronic inflammation. Increased hemodynamic stress acting at the site of bifurcation of cerebral arteries triggers an inflammatory response mediated by various proinflammatory molecules in arterial walls, inducing pathological changes in the models similar to those observed in the walls of human CAs. Findings from animal studies have provided new insights into CA formation and may contribute to the development of new therapeutic drugs for CAs.

Dihydrotestosterone suppresses foam cell formation and attenuates atherosclerosis development

The role of testosterone in atherosclerosis remains unclear because it is aromatized to estrogen. We investigated the effect of the nonaromatized natural androgen 5alpha-dihydrotestosterone (DHT) on the rabbit atherogenesis in relation to the proatherogenic molecule lectin-like oxidized-low-density lipoprotein receptor-1 (LOX-1) and its downstream molecules. Thirty-nine male New Zealand white rabbits were divided into four groups: 1) noncastrated group with normal chow diet (n = 6); 2) noncastrated group with high-cholesterol diet (HCD) (n = 10); 3) castrated group with HCD plus sc placebo pellet (n = 11); and 4) castrated group with HCD plus sc 150 mg DHT pellet (n = 12). Implantation of sc DHT or placebo pellet was performed at the time of castration. After castration or sham operation, the rabbits were fed the HCD for 8 wk, and plaque areas were assessed in the entire aorta. The HCD-induced increase in plaque area, which was most aggravated in the castration plus placebo group, was attenuated in the castration plus DHT group. Microscopic examination of the proximal descending aorta revealed that DHT significantly reduced HCD-induced foam cell formation, which was mostly composed of macrophages in the intima layer, compared with the placebo group. The decreased accumulation of foam cells with DHT treatment was accompanied by a marked reduction in the expression of LOX-1 mRNA in these cells. In cultured macrophages prepared from male wild-type mice that express the androgen receptor (AR), 1 x 10(-8) m and 1 x 10(-9) m DHT inhibited the formation of foam cells induced by oxidized low-density lipoprotein. Moreover, the expression of LOX-1 and inflammatory cytokines in the cultured macrophages was significantly suppressed by DHT. Such suppressive effects of DHT on foam cell formation and cytokine expression were not observed in cultured macrophages prepared from male AR-null mice, suggesting an involvement of AR in the mechanism. In conclusion, physiological levels of DHT attenuated the development of atherosclerosis in rabbits through the suppression of intimal foam cell formation of macrophage partly via the suppression of LOX-1 expression.

Effects of pitavastatin on monocyte chemoattractant protein-1 in hyperlipidemic patients

The effects of statins on platelet activation markers, chemokines and adiponectin, were investigated in 135 patients with hyperlipidemia. Of the 135 hyperlipidemic patients, 63 were allocated to the simvastatin group, treated with simvastatin at the dose of 10 mg daily, and the remaining 72 were allocated to the pitavastatin group, treated with pitavastatin at the dose of 2 mg daily. Plasma levels of platelet-derived microparticles (PDMP), cell adhesion molecules (sCD40L and sP-selectin), chemokines [monocyte chemoattractant protein-1 (MCP-1) and regulated on activation normally T-cell expressed and secreted] and adiponectin were measured at the baseline and after 6 months of treatment in both the groups. In addition, we carried out a basic study to investigate the MCP-1-dependent induction of tissue factor expression on a histiocytic cell line (U937 cells). The plasma levels of PDMP, sCD40L, sP-selectin, regulated on activation normally T-cell expressed and secreted and MCP-1 were higher, whereas those of adiponectin were lower, in the hyperlipidemic patients than in the normolipidemic controls. Plasma PDMP and sCD40L were positively correlated, whereas plasma adiponectin was negatively correlated, with the plasma levels of MCP-1. No significant differences in the plasma levels of PDMP, sCD40L, sP-selectin, regulated on activation normally T-cell expressed and secreted and MCP-1 measured before and after treatment were observed in either the simvastatin or pitavastatin group. A significant increase of the plasma adiponectin levels was observed after 6 months of treatment with pitavastatin but not after an equal duration of treatment with simvastatin. When pitavastatin-treated patients were divided into two groups according to the adiponectin response to pitavastatin treatment, significant decreases of the plasma MCP-1, PDMP and sCD40L levels were observed after pitavastatin treatment in the responder group. In the aforementioned basic study, MCP-1 by itself did not induce the expression of tissue factor on the U937 cells. However, the recombinant sCD40L-induced expression of tissue factor on U937 was enhanced by the addition of MCP-1. These findings suggest that PDMP, sCD40L and MCP-1 may participate in the development of atherothrombosis in patients with hyperlipidemia and that pitavastatin may exert an adiponectin-dependent antiatherothrombotic effect in hyperlipidemic patients.

Experimental models investigating the inflammatory basis of atherosclerosis

Inflammation is considered an important aspect in the development of atherosclerosis. Genetic manipulations of animal models susceptible to atherosclerosis have unraveled the contribution of various inflammatory pathways implicated in the development of atherosclerosis. These inflammatory pathways not only lead to the recruitment and entry of inflammatory cells into the arterial wall, they also modify the morphology and composition of atherosclerotic plaques. Certain inflammatory pathways, such as P-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, appear to play an important role in lesion initiation, whereas others, such as interleukin-10 and CD40/CD40 ligand, seem to contribute to lesion progression and morphologic changes. An understanding of these pathways will allow the development of new strategies in the management of atherosclerosis. This review provides a roadmap for better utilization of these models in atherosclerosis research.

Adiponectin incompletely prevent MCP-1-dependent restenosis after percutaneous coronary intervention [corrected] in patients with coronary artery disease

BACKGROUND

Some factors play pathogenic roles in the development of restenosis after percutaneous coronary intervention (PCI). We measured and compared the ratio of elevated levels of monocytic chemotactic peptide-1 (MCP-1), regulated on activation normally T-cell expressed and secreted (RANTES), soluble (s) P-selectin, sE-selectin and adiponectin after PCI.

METHODS

Plasma levels of chemokines and soluble markers were measured before and 30 days after PCI in 96 patients (69 males and 27 females, aged 63 +/- 9 years) who underwent PCI and who had repeated angiograms at a 6-month follow-up. In addition, we carried out the basic study of the tissue factor expression on monocytic cell line (THP-1) by MCP-1.

RESULTS

Restenosis occurred in 33 (34.4%) patients. A significant and time-dependent increase in MCP-1 was observed in the restenosis group. However, there were no significant differences in RANTES, sP-selectin, and sE-selectin levels with or without restenosis. Adiponectin levels in patients with coronary artery disease were significantly lower than levels in normal controls. However, adiponectin levels were no different at baseline between patients with or without restenosis. MCP-1 did not induce the expression of tissue factor on THP-1. However, the recombinant sCD40 ligand-induced expression of tissue factor on THP-1 was enhanced by the addition of MCP-1.

CONCLUSION

These findings suggest that restenosis development after PCI in patients with coronary artery disease may involve the participation of MCP-1 after PCI, and adiponectin incompletely prevent this MCP-1-dependent restenosis.

Fas-mediated upregulation of vascular endothelial growth factor and monocyte chemoattractant protein-1 expression in cultured dermal fibroblasts: Role in the inflammatory response

The Fas-Fas ligand interaction is the most important pathway in starting apoptosis. In addition, several recent reports have emerged documenting non-apoptotic roles for Fas. However, a non-apoptotic role of Fas in dermal fibroblasts remains unknown. The present study investigated whether Fas stimulation not only promotes apoptosis but also stimulates elements of the inflammatory response such as angiogenesis and macrophage infiltration. Fas stimulation was performed by treating cultured human dermal fibroblasts with an agonistic anti-Fas monoclonal antibody (mAb). Anti-Fas mAb-treated fibroblasts showed a significantly greater increase of caspase-3 and caspase-8 activity compared with control fibroblasts. Addition of the anti-Fas mAb induced DNA fragmentation, as confirmed by the DNA ladder assay. Terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling (TUNEL) staining showed that treatment with the anti-Fas mAb induced an increase of apoptotic fibroblasts in a time-dependent manner. At both mRNA and protein levels, anti-Fas mAb-treated fibroblasts showed significantly higher expression of vascular endothelial growth factor (VEGF) and monocyte chemoattractant protein (MCP)-1 compared with control fibroblasts. A pan-caspase inhibitor (Z-VAD-FMK) significantly inhibited VEGF and MCP-1 expression. After transplantation of fibroblasts into mice with severe combined immunodeficiency, the nodules derived from anti-Fas mAb-treated fibroblasts showed more abundant neovascularization, increased macrophage infiltration, and more apoptotic cells in comparison with nodules derived from control fibroblasts. The results of both in vitro and in vivo studies confirmed significantly higher angiogenic activity and macrophage chemotactic activity of anti-Fas mAb-treated fibroblasts compared with control fibroblasts.

Monocyte chemoattractant protein-1 and coronary artery disease

The designation of atherosclerosis as a chronic inflammatory process represents an exciting and logical paradigm shift for cardiologists. Monocyte chemoattractant protein-1 (MCP-1) plays an important role in the recruitment and activation of monocytes and thus in the development of atherosclerosis. Enhanced MCP-1 expression has been detected in macrophages, endothelial cells, and vascular smooth muscle cells in the atheromatous plaque. Activation of macrophages by MCP-1 also appears to be involved in the vulnerability of the plaque. Indeed, circulating MCP-1 levels are elevated in patients with acute myocardial infarction and in those with unstable angina, but not in patients with stable angina. Production of MCP-1 and macrophage accumulation are also observed after coronary angioplasty or grafting, indicating that MCP-1 expression may be related not only to instability of atheromatous plaques, but also to the formation of restenotic lesions. The development of therapeutic drugs for atherosclerosis targeted specially against MCP-1 may be useful in the prevention of plaque formation and future myocardial infarction.

Monocyte accumulation in mouse atherogenesis is progressive and proportional to extent of disease

Monocytes participate importantly in the pathogenesis of atherosclerosis, but their spatial and temporal recruitment from circulation remains uncertain. This study tests the hypothesis that monocyte accumulation in atheroma correlates with the extent of disease by using a sensitive and simple quantitative assay that allows tracking of highly enriched populations of blood monocytes. A two-step isolation method yielded viable and functionally intact highly enriched peripheral blood monocyte populations (>90%). Recipient mice received syngeneic monocytes labeled in two ways: by transgenically expressing EGFP or with a radioactive tracer [(111)In]oxine. After 5 days, more labeled cells accumulated in the aorta, principally the aortic root and ascending aorta, of 10-wk-old ApoE(-/-) compared with 10-wk-old C57BL/6 mice (223 +/- 3 vs. 87 +/- 22 cells per aorta). Considerably more monocytes accumulated in 20-wk-old ApoE(-/-) mice on either chow (314 +/- 41 cells) or high-cholesterol diet (395 +/- 53 cells). Fifty-week-old ApoE(-/-) mice accumulated even more monocytes in the aortic root, ascending aorta, and thoracic aorta after both chow (503 +/- 67 cells) or high-cholesterol diet (648 +/- 81 cells). Labeled monocyte content in the aorta consistently correlated with lesion surface area. These data indicate that monocytes accumulate continuously during atheroma formation, accumulation increases in proportion to lesion size, and recruitment is augmented with hypercholesterolemia. These results provide insights into mechanisms of atherogenesis and have implications for the duration of therapies directed at leukocyte recruitment.

Autologous apoptotic cell engulfment stimulates chemokine secretion by vascular smooth muscle cells

Apoptosis of vascular smooth muscle cells (VSMCs) occurs in vivo under both physiological and pathological settings. The clearance of apoptotic cells may be accomplished in part by the surrounding normal VSMCs. However, the fate of internalized apoptotic cells, the rate of intracellular degradation, and the consequences of these processes to VSMC biology are unknown. Electron microscopy and confocal fluorescence imaging showed that rat VSMCs effectively bound and internalized autologous apoptotic VSMCs in vitro. Within 2 hours, the internalized apoptotic cells were delivered to lysosomes, and the majority of these internalized cells and their proteins were efficiently degraded by 24 hours. After degradation was completed, the phagocytic VSMCs remained viable with normal rates of proliferation. Clearance of apoptotic cells by VSMCs did not induce the release of vascular wall matrix proteases but was associated with a 1.6-fold increase in transforming growth factor-beta1 release. Interestingly, clearance of apoptotic cells stimulated VSMCs to secrete monocyte-chemoattractant protein-1 and cytokine-induced neutrophil chemoattractant. The coordinated release of transforming growth factor-beta1 and chemokines suggests that autologous apoptotic cell clearance stimulates VSMCs to release molecules that specifically recruit professional phagocytes while simultaneously dampening the inflammatory response and preventing vascular injury.

Broad-spectrum chemokine inhibition reduces vascular macrophage accumulation and collagenolysis consistent with plaque stabilization in mice

BACKGROUND

A major determinant of the risk of myocardial infarction is the stability of the atherosclerotic plaque. Macrophage-rich plaques are more vulnerable to rupture, since macrophages excrete an excess of matrix-degrading enzymes over their inhibitors, reducing collagen content and thinning the fibrous cap. Several genetic studies have shown that disruption of signalling by the chemokine monocyte chemoattractant protein 1 reduced the lipid lesion area and macrophage accumulation in the vessel wall.

METHODS

We have tested whether a similar reduction in macrophage accumulation could be achieved pharmacologically by treating apolipoprotein-E-deficient mice with the chemokine inhibitor NR58-3.14.3.

RESULTS

Mice treated for various periods of time (from several days to 6 months) with NR58-3.14.3 (approximately 30 mg/kg/day) consistently had 30-40% fewer macrophages in vascular lesions, compared with mice treated with the inactive control NR58-3.14.4 or PBS vehicle. Similarly, cleaved collagen staining was lower in mice treated for up to 7 days, although this effect was not maintained when treatment time was extended to 12 weeks. The vascular lipid lesion area was unaffected by treatment, but total collagen I staining and smooth muscle cell number were both increased, suggesting that a shift to a more stable plaque phenotype had been achieved.

CONCLUSIONS

Strategies, such as chemokine inhibition, to attenuate macrophage accumulation may therefore be useful to promote stabilization of atherosclerotic plaques.

Enhanced Coronary Calcification Determined by Electron Beam CT Is Strongly Related to Endothelial Dysfunction in Patients With Suspected Coronary Artery Disease

BACKGROUND

Coronary artery calcification determined by electron beam CT (EBCT) is strongly associated with total plaque burden but is not related to systemic vascular inflammation.

AIMS

We sought to test the hypothesis that enhanced coronary artery calcification, a marker of atherosclerosis and plaque burden, was related to endothelial dysfunction in patients with suspected coronary artery disease (CAD).

METHODS AND RESULTS

One hundred twenty-four subjects with suspected CAD were enrolled. Coronary artery calcification was detected by EBCT. A noninvasive method of brachial ultrasound was used to measure endothelium-dependent flow-mediated vasodilation (FMD) and endothelium-independent nitroglycerin-mediated vasodilation (NMD). Serum high-sensitivity C-reactive protein (hsCRP) and monocyte chemoattractant protein-1 (MCP-1) levels were also determined. Of the 124 patients, the calcium scores ranged from 0 to 4,394. All subjects were classified into three groups according to coronary calcium scores: group 1, score 0 (n = 26); group 2, scores 1 to 199 (n = 50); group 3, scores > or = 200 (n = 48). There was an inverse association between the degree of coronary artery calcification and the endothelium-dependent FMD in the three groups (6.9 +/- 0.6% vs 5.3 +/- 0.3% vs 3.7 +/- 0.3%, respectively; p < 0.001) but not the endothelium-independent NMD. Besides, no significant difference in serum levels of hsCRP and MCP-1 were found among the three groups. However, both the serum levels of hsCRP and MCP-1 were correlated significantly with endothelium-dependent FMD (r = - 0.211, p = 0.019; and r = - 0.188, p = 0.037, respectively). By multivariate analysis, enhanced coronary calcification was a strong independent predictor of endothelial dysfunction (p < 0.001).

CONCLUSION

Enhanced coronary artery calcification strongly predicted endothelial dysfunction in patients with suspected CAD. Also, serum levels of hsCRP and MCP-1 were significantly correlated with endothelial function. These findings suggested that both calcium deposition and inflammation were involved in endothelial dysfunction.

Ramatroban (BAY u 3405): a novel dual antagonist of TXA2 receptor and CRTh2, a newly identified prostaglandin D2 receptor

It is known that thromboxane A2 (TXA2) contributes to various diseases such as bronchial asthma, ischemic heart disease, cerebrovascular disorders and allergic rhinitis. A number of TXA2 synthase inhibitors and TXA2 receptor (TP receptor) antagonists have been developed to treat these diseases. Ramatroban (BAY u 3405) was developed as a potent TP receptor antagonist with excellent efficacy against allergic rhinitis in many animal models and patients. Recent studies also revealed that ramatroban can block the newly identified PGD2 receptor, chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTh2). PGD2 induces migration and degranulation of eosinophils through CRTh2 and contributes to late-phase inflammation and cell damage. Accordingly, it was considered that ramatroban suppresses the late-phase inflammation via TP receptor and CRTh2 blockade. In terms of the efficacy on vascular systems, it was revealed that ramatroban can suppress the expression of monocyte chemoattractant protein-1 (MCP-1) and adhesion molecules in endothelial cells and prevent exacerbation of inflammation by blocking these responses. According to our recent studies in hypercholesterolemic rabbits ramatroban prevents macrophage infiltration through MCP-1 downregulation and neointimal formation after balloon injury and attenuates vascular response to acetylcholine. Therefore, ramatroban may be beneficial in the treatment of atherosclerosis.

Red wine polyphenolic compounds inhibit atherosclerosis in apolipoprotein E-deficient mice independently of effects on lipid peroxidation

BACKGROUND

Lipid peroxidation is thought to play an important role in the pathogenesis of atherosclerosis. Fatty acid peroxidation products such as hydroxyeicosatetraenoic acids and F(2)-isoprostanes have been found in advanced human atherosclerotic plaques. However, little is known about the formation of these products during lesion development.

OBJECTIVE

This study examined stable biomarkers of lipid oxidative damage in relation to atherosclerotic disease progression in apolipoprotein E-deficient (Apoe(-/-)) mice and retardation of the disease by red wine polyphenols.

DESIGN

One hundred male Apoe(-/-) mice and 50 male control (C57BL/6J) mice were given a high-fat, high-cholesterol diet for 20 wk. To examine the effect of the polyphenolic compounds on lesion development, 50 of the Apoe(-/-) mice were also given dealcoholized red wine for the duration of the study.

RESULTS

Aortic lipid deposition was significantly greater in the Apoe(-/-) mice than in the control mice (P < 0.01). Plasma and aortic F(2)-isoprostanes did not differ between the treatment groups. Plasma concentrations of monocyte chemoattractant protein 1, which has been implicated in the development of atherosclerosis, were significantly higher in the Apoe(-/-) mice than in the control mice up to 16 wk (P < 0.05). Hydroxyeicosatetraenoic acid concentrations increased significantly over time in all groups (P < 0.05). Red wine polyphenols had no effect on markers of lipid peroxidation or monocyte chemoattractant protein 1 concentrations, but lipid deposition in the aorta at age 26 wk was significantly less in the mice given red wine than in those not given red wine.

CONCLUSION

These results suggest that lipid deposition is independent of lipid oxidation and that the protective action of red wine polyphenols is independent of any antioxidant action of these compounds.

Plasma Concentrations of Monocyte Chemoattractant Protein 1 (MCP-1) and Neopterin in the Coronary Circulation of Patients With Coronary Artery Disease-Association With the Severity of Coronary Atherosclerosis-

BACKGROUND

The dynamics of MCP-1 and neopterin and the relation between their concentrations in coronary circulation and the severity of coronary atherosclerosis were evaluated in patients with stable coronary artery disease (CAD).

METHODS AND RESULTS

Blood samples were obtained from the aortic root (Ao) and coronary sinus (CS) of 78 patients who underwent coronary angiography. Plasma MCP-1 and neopterin concentrations were measured using an enzyme-linked immunosorbent assay method and the CS-Ao differences were calculated. The severity of coronary heart disease (CHD) was evaluated in 52 patients who had no history of coronary angioplasty, using 3 coronary scoring systems: the clinical 1- to 3-vessel disease score, the American Heart Association extension score (1-15 segments), and the Gensini score. The plasma MCP-1 and neopterin concentrations increased significantly with age. The CS-Ao differences for neopterin showed weak, but significant, positive correlation with the Gensini score (r=0.347, p=0.013). There were no correlations among the MCP-1 concentrations in the Ao or CS, or in the CS-Ao difference, with the severity of CHD.

CONCLUSIONS

The results indicate that neopterin is a useful marker of the severity of coronary atherosclerosis in patients with stable CAD, acting as an index of the activity of monocytes/macrophages.

Role of monocytes in atherogenesis

This review focuses on the role of monocytes in the early phase of atherogenesis, before foam cell formation. An emerging consensus underscores the importance of the cellular inflammatory system in atherogenesis. Initiation of the process apparently hinges on accumulating low-density lipoproteins (LDL) undergoing oxidation and glycation, providing stimuli for the release of monocyte attracting chemokines and for the upregulation of endothelial adhesive molecules. These conditions favor monocyte transmigration to the intima, where chemically modified, aggregated, or proteoglycan- or antibody-complexed LDL may be endocytotically internalized via scavenger receptors present on the emergent macrophage surface. The differentiating monocytes in concert with T lymphocytes exert a modulating effect on lipoproteins. These events propagate a series of reactions entailing generation of lipid peroxides and expression of chemokines, adhesion molecules, cytokines, and growth factors, thereby sustaining an ongoing inflammatory process leading ultimately to lesion formation. New data emerging from studies using transgenic animals, notably mice, have provided novel insights into many of the cellular interactions and signaling mechanisms involving monocytes/macrophages in the atherogenic processes. A number of these studies, focusing on mechanisms for monocyte activation and the roles of adhesive molecules, chemokines, cytokines and growth factors, are addressed in this review.

Ramatroban, a thromboxane A2 receptor antagonist, prevents macrophage accumulation and neointimal formation after balloon arterial injury in cholesterol-fed rabbits

Macrophage infiltration appears to play an important role in restenosis after arterial intervention. Monocyte chemoattractant protein-1 (MCP-1) is a major chemotactic factor for macrophages. We have previously shown that ramatroban, a thromboxane A(2) (TXA(2)) receptor antagonist, diminished the expression of MCP-1 in human vascular endothelial cells. The aim of this study was to evaluate whether, after balloon angioplasty of atherosclerotic arteries, ramatroban would reduce MCP-1 expression, macrophage accumulation, and neointimal formation. New Zealand white rabbits were fed a cholesterol-rich diet for 4 weeks, and the abdominal aorta of the rabbits were injured by a 2-French Fogarty catheter. They were randomized to receive 1 or 5 mg/kg daily of ramatroban (n = 7 or n = 8) or saline (n = 6). At 4 weeks after balloon angioplasty, the intimal hyperplasia and the macrophage-positive area in the intima by the ramatroban treatment was significantly reduced. Monocyte chemoattractant protein-1 gene expression in injured aortas of the ramatroban-treated group was significantly less evident than in the vehicle-treated group. Thromboxane A(2) receptor blockade by ramatroban for 4 weeks after balloon angioplasty in the atherosclerotic rabbits prevented macrophage infiltration through MCP-1 downregulation and neointimal formation.

Long-term treatment with propagermanium suppresses atherosclerosis in WHHL rabbits

Macrophages play an important role in the pathogenesis of atherosclerosis, for which monocyte chemoattractant protein (MCP)-1 and CCR2 chemokine receptors may be involved. The authors have recently demonstrated that propagermanium exerts inhibitory effect on the CCR2 receptors. In the current study, the authors examined whether the organic germanium suppresses the MCP-1-induced monocyte migration in vitro and the development of atherosclerosis in WHHL rabbits in vivo. In the in vitro experiment, propagermanium concentration-dependently suppressed the MCP-1-induced migration of THP-1 cells. In the in vivo experiment, 20 WHHL rabbits were randomly divided into two groups; one group was treated with oral administration with propagermanium (9 mg/kg/day) for 3 months, and another group served as a control (n = 10 each). After 3 months, the aorta was isolated and stained with oil red O staining, and neointimal formation was quantified. Macrophage accumulation in the aorta was also evaluated by immunostaining. Long-term treatment with propagermanium did not affect the serum lipid profiles. However, the treatment significantly suppressed the oil red O-positive area of the total aorta (p < 0.05). Similarly, propagermanium significantly suppressed the intimal lesions (maximal intimal thickness and intimal area) and macrophage staining-positive area (all p < 0.05). A significant positive correlation was noted between macrophage staining-positive area and intimal lesions (p < 0.0001). These results indicate that long-term treatment with propagermanium suppresses the development of atherosclerosis in WHHL rabbits, suggesting its usefulness for the treatment of atherosclerotic vascular disease in humans.

Intravenous prostaglandin E1 reduces monocyte chemoattractant protein-1 levels in peripheral arterial obstructive disease

OBJECTIVES

Blood monocytes are the precursors of the lipid-laden foam cells that are the hallmark of early atherosclerotic lesions, and monocyte chemoattractant protein-1 (MCP-1) plays important roles in their recruitment to the vessel wall. In this study, we measured serum levels of MCP-1 in patients with peripheral arterial obstructive disease (PAOD) and investigated whether intravenous prostaglandin E1 (PGE1) treatment, which produces clinical benefits in PAOD, might decrease such levels.

METHODS

Eight patients with PAOD at Fontaine stage II to IV were treated with a daily intravenous infusion of 10 microg of PGE1 for 7 consecutive days. Blood samples before and after 7-day PGE1 treatment were used for assays of MCP-1, interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), von Willebrand factor (vWF), and endothelin-1 (ET-1).

RESULTS

Serum MCP-1 levels in patients with PAOD were significantly higher than those in healthy control subjects (263.8 +/- 52.8 vs 136.5 +/- 15.0 pg/mL, P =.002). PGE1 administration for 7 days resulted in a significant decrease in the MCP-1 level, from 263.8 +/- 52.8 to 196.1 +/- 25.5 pg/mL (P =.02), whereas levels of IL-6, hs-CRP, and ET-1 and the activity of vWF were not affected.

CONCLUSIONS

Serum MCP-1 levels were elevated in patients with PAOD, indicating the involvement of activation of monocytes in the pathogenesis of this disorder. Parenteral administration of PGE1 appeared to decrease circulating MCP-1 levels, which might lead to the suppression of the development of atherosclerotic lesions in patients with PAOD.

The use of (99m)technetium-labeled MCP-1 to assess graft coronary artery disease in rat cardiac allografts

BACKGROUND

Monocyte chemoattractant protein-1 (MCP-1) is associated with the development of graft coronary artery disease (GCAD) following cardiac transplantation. This study assessed whether technetium 99m ((99m)Tc)-labeled MCP-1 binds its receptors in chronic cardiac transplants and thereby provides a potential modality to assess GCAD.

METHODS

Allogeneic (PVG-->ACI, n = 9) and syngeneic (ACI-->ACI, n = 9) rat heterotopic heart transplants were performed. Allograft recipients were treated with 7.5 mg/kg per day of Cyclosporin A for 10 days until tolerance was achieved. After 90 days, animals were injected intravenously with (99m)Tc-MCP-1 and killed after 1 hour. Radioactivity of heart tissues was measured and standardized to uptake in the overall blood pool. Two-dimensional (99m)Tc-MCP-1 uptake (autoradiographs) was imaged by exposing 50-microm sections on a phosphoimager overnight. ED-1 staining of monocyte/macrophages was performed on serial sections. Additional sections were stained with elastin von Gieson and hematoxylin. Hearts were scored for luminal narrowing and intima/media ratio (I/M) with computerized image analysis.

RESULTS

Allografts exhibited significantly more luminal narrowing (22.5 +/- 10.7% vs 2.6 +/- 4.6, p = 0.0005) and higher I/M (0.173 +/- 0.151 vs 0.015 +/- 0.029, p = 0.0088) than isografts. The ratio of (99m)Tc-MCP-1 uptake in allografts (1.04 +/- 0.4) was greater than that of isograft controls (0.72 +/- 0.11, p = 0.03). Pixel counts of autoradiographs and ED-1-stained sections demonstrated a modest correlation between the two (R(2) = 0.50). No significant differences were seen in acute rejection scores.

CONCLUSION

(99m)Tc-MCP-1 uptake was higher in allografts vs isografts and was consistent with a greater degree of GCAD. These data demonstrating increased radiopharmaceutical uptake in hearts with GCAD provide a foundation for the development of a potentially non-invasive imaging assay of this disease process in heart transplantation.

Alteration of a macrophages inflammatory protein-related protein-2 (MRP-2) response by high fat and cholesterol diet in mice

Macrophage inflammatory protein-related protein-2 (MRP-2) is a new member of the CC chemokine family that is recently identified in murine macrophages. MRP-2 is involved in leukocyte trafficking and activation, which can be implicated in inflammatory diseases including atherosclerosis. Little is known about the involvement of this novel chemokine MRP-2 in the pathogenesis of atherosclerosis. To explore the possible association of the MRP-2 with atherosclerosis, we investigated the effects of atherogenic diet on MRP-2 expression in mice. Male C57BL/6 mice were fed a high fat and cholesterol diet (20% fat and 1.5% cholesterol) or a control diet based on AIN-76 for 5, 10, or 14 weeks. The levels of total cholesterol, LDL cholesterol, and F2-isoprostanes in plasma were measured using appropriate enzymatic assays. Tumor necrosis factor alpha (TNF alpha) and MCP-1 release by peritoneal macrophages was determined by ELISA. The mRNA expression level of the MRP-2 was measured by RT-PCR. The levels of total cholesterol, LDL-cholesterol, and 8-iso-prostaglandin F2 alpha in plasma, well-known indexes of atherosclerosis, were significantly increased in the high fat and cholesterol diet group compared to those in the control. A significant increase in the TNF alpha and MCP-1 production by macrophages was also observed in the group fed high fat and cholesterol diet. The mRNA expression of MRP-2 was upregulated by oxLDL treatment in vitro and feeding a high fat and cholesterol diet in vivo at the late stage of atherosclerosis. These results suggest that MRP-2 may be an important contributing factor in the development of atherosclerosis.

Loss of lymphotoxin-alpha but not tumor necrosis factor-alpha reduces atherosclerosis in mice

Inflammatory processes are involved with all phases of atherosclerotic lesion growth. Tumor necrosis factor-alpha (TNFalpha) is an inflammatory cytokine that is thought to contribute to lesion development. Lymphotoxin-alpha (LTalpha) is also a proinflammatory cytokine with homology to TNFalpha. However, its presence or function in lesion development has not been investigated. To study the role of these molecules in atherosclerosis, the expression of these cytokines in atherosclerotic lesions was examined. The presence of both cytokines was observed within aortic sinus fatty streak lesions. To determine the function of these molecules in regulating lesion growth, mice deficient for TNFalpha or LTalpha were examined for induction of atherosclerosis. Surprisingly, loss of TNFalpha did not alter lesion development compared with wild-type mice. This brings doubt to the generally held concept that TNFalpha is a "proatherogenic cytokine." However, LTalpha deficiency resulted in a 62% reduction in lesion size. This demonstrates an unexpected role for LTalpha in promoting lesion growth. The presence of LTalpha was observed in aortic sinus lesions suggesting a direct role of LTalpha in modulating lesion growth. To determine which receptor mediated these responses, diet-induced atherosclerosis in mice deficient for each of the TNF receptors, termed p55 and p75, was examined. Results demonstrated that loss of p55 resulted in increased lesion development, but loss of p75 did not alter lesion size. The disparity in results between ligand- and receptor-deficient mice suggests there are undefined members of the TNF ligand and receptor signaling pathway involved with regulating atherogenesis.

Endothelial IKK beta signaling is required for monocyte adhesion under laminar flow conditions

Endothelial activation induces expression of pro-inflammatory molecules that are thought to play an important role in atherogenesis through enhanced vascular monocyte recruitment. Many pro-inflammatory endothelial signals are transcriptionally regulated by members of the NF- kappa B family. The serine-threonine kinase, IKK beta, can mediate NF- kappa B activation although several alternative pathways exist. To test whether IKK beta is necessary for cytokine activation of human vascular endothelium and endothelial recruitment of human monocytes under laminar flow, we constructed a recombinant adenoviral vector carrying a dominant negative mutant of IKK beta (Ad.dnIKK beta) to transduce human umbilical vein endothelial cells (HUVEC) in vitro. We found that dnIKK beta expression effectively blocked NF-kappa B activation as assessed by nuclear translocation of NF-kappa B, I kappa B degradation, and NF-kappa B dependent reporter expression, without affecting activation of the other relevant signaling pathways, SAPK/JNK and p38. Furthermore, overexpression of dnIKK beta in TNF-alpha-stimulated HUVEC blocked induction of the surface adhesion molecules E-selectin, ICAM-1, and VCAM-1. Under simulated physiologic flow conditions, both firm adhesion and rolling of human peripheral monocytes on dnIKK beta-transduced endothelial monolayers were markedly inhibited. We conclude that IKK beta is necessary for the cytokine-induced inflammatory phenotype of human endothelium and endothelial recruitment of human monocytes under flow.

Effect of hormone replacement therapy on nitric oxide bioactivity and monocyte chemoattractant protein-1 levels

BACKGROUND

Vascular inflammation plays an important role in the pathogenesis of atherosclerosis. We investigated the effect of hormone replacement therapy (HRT) on vasomotor function and monocyte chemoattractant protein (MCP)-1 levels, an important serological marker of inflammation.

METHODS

We administered micronized progesterone (MP) 200 mg for 10 days with conjugated equine estrogen (CEE) 0.625 mg for 25 days and remaining 5 days off cyclically during 2 months to 20 healthy postmenopausal women (PMW). We measured NO bioactivity and plasma levels of MCP-1 before and after HRT in 20 PMW. And we measured plasma levels of MCP-1 in each 20 subjects of premenopausal women, men <50, and men >50 years, respectively.

RESULTS

MP combined with CEE significantly improved the percent flow-mediated dilator response to hyperemia relative to baseline measurements (P<0.001). PMW receiving HRT had lower levels of MCP-1 than those not receiving HRT (121+/-38 versus 146+/-44 pg/ml, P<0.001). In all comparisons, subjects with high estrogen status had significantly lower MCP-1 levels than subjects with low estrogen status (P<0.001 by ANOVA). Premenopausal women had lower levels of MCP-1 than men of a similar age (106+/-14 versus 164+/-40 pg/ml, P<0.001). PMW not receiving HRT had similar levels of MCP-1 compared with men of a similar age (146+/-44 versus 143+/-29 pg/ml, P=0.816). Premenopausal women had markedly lower levels of MCP-1 than PMW not receiving HRT (106+/-14 versus 146+/-44 pg/ml, P=0.001). PMW receiving HRT had similar levels of MCP-1 compared with premenopausal women (121+/-38 versus 106+/-14 pg/ml, P=0.323).

CONCLUSION

These findings might provide at least a partial explanation for the protection against cardiovascular disease experienced by premenopausal women, and the loss of that protection following menopause.

Increased plasma antigen levels of monocyte chemoattractant protein-1 in patients with restenosis after percutaneous transluminal coronary angioplasty

Monocyte chemoattractant protein-1 (MCP-1) plays an important role in the progression of atherosclerosis in coronary arteries. To examine whether or not plasma antigen levels of MCP-1 are related to restenosis after percutaneous transluminal coronary angioplasty (PTCA), the plasma antigen levels of MCP-1 were measured by enzyme-linked immunosorbent assay (pg/ml) before, 24 and 48 h, and 3 months after elective PTCA for stable exertional angina performed between June 1997 and March 1998. Restenosis was defined as recurrence of stenosis greater than 50% of the diameter in the dilated segment at 3-month follow-up angiography. There were no differences in plasma MCP-1 antigen levels before and at 24 h after PTCA between restenosis (R; n=27) and no-restenosis (N; n=43) groups (R vs N: 633+/-35 vs 589+/-34, and 669+/-41 vs 575+/-36 pg/ml before and at 24 h after PTCA, respectively), but plasma MCP-1 antigen levels were higher at 48 h and 3 months after PTCA in the R than in N group (R vs N: 678+/-41 vs 558+/-35, and 735+/-35 vs 571+/-32 pg/ml at 48 h and 3 months after PTCA, respectively). These data suggest that the MCP-1 production and macrophage accumulation in the balloon-injured site is partially associated with restenosis after PTCA.

The role of CBP in estrogen receptor cross-talk with nuclear factor-kappaB in HepG2 cells

Functional interactions or cross-talk between ligand-activated nuclear receptors and the proinflammatory transcription factor nuclear factor-kappaB (NF-kappaB) may play a major role in ligand-mediated modification of diseases processes. In particular, the cardioprotective effects of estrogen replacement therapy are thought to be due in part to the ability of ligand-bound estrogen receptor (ER) to inhibit NF-kappaB function. In the current study 17beta-estradiol-bound ERalpha interfered with cytokine-induced activation of a NF-kappaB reporter in HepG2 cells. The estrogen metabolite, 17alpha-ethinyl estradiol, and the phytoestrogen, genistein, were also effective inhibitors of NF-kappaB activation, whereas tamoxifen, 4-hydroxytamoxifen, and raloxifene were inactive. This inhibition was reciprocal, as NF-kappaB interfered with the trans-activation properties of ERalpha. Ligand-bound ERalpha did not inhibit NF-kappaB binding to DNA, but it did decrease the histone acetyltransferase activity required for NF-kappaB transcriptional activity. Coexpression of the transcription coactivator CREB binding protein (CBP), but not steroid receptor coactivator 1a, reversed the ERalpha-mediated inhibition of NF-kappaB activity. Mammalian two-hybrid experiments also revealed that ligand-bound ERalpha can interact functionally with CBP-NF-kappaB complexes. We suggest that CBP targeting by ERalpha results in the inhibition of NF-kappaB and may occur through formation of transcriptionally inert multimeric complexes that are dependent upon the nature of the ERalpha ligand.

Fas/FADD-mediated activation of a specific program of inflammatory gene expression in vascular smooth muscle cells

Apoptosis of smooth muscle cells is a common feature of vascular lesions but its pathophysiological significance is not known. We demonstrate that signals initiated by regulated Fas-associated death domain protein overexpression in rat vascular smooth muscle cells in the carotid artery induce expression of monocyte-chemoattractant protein-1 and interleukin-8, and cause massive immigration of macrophages in vivo. These chemokines, and a specific set of other pro-inflammatory genes, are also upregulated in human vascular smooth muscle cells during Fas-induced apoptosis, in part through a process that requires interleukin-1alpha activation. Induction of a pro-inflammatory program by apoptotic vascular smooth muscle cells may thus contribute to the pathogenesis of vascular disease.

The value of apolipoprotein E knockout mice for studying the effects of dietary fat and cholesterol on atherogenesis

The ability of the apolipoprotein E-deficient mouse to develop spontaneous atherosclerosis, which resembles the human process, is an excellent model in which to assess the impact of dietary factors. This review discusses the role of several nutrients in the development of atherosclerosis and the mechanisms through which they act.