Monocyte chemoattractant protein-1--a major contributor to the inflammatory process associated with diabetes

Oleacein: A comprehensive review of its extraction, purification, absorption, metabolism, and health effects

Extra virgin olive oil (EVOO) consumption reduces the risk of cardiovascular disease in high-risk groups and the polyphenols in EVOO play an important health effect on it. As one of the most abundant polyphenols in EVOO, oleacein (OLEA) has many health benefits. However, there is no review article that focus comprehensively on OLEA, and most articles have limited data and information on OLEA. The purpose of this review is to summarize the results of all available studies, to present and compare the main traditional and novel techniques for the extraction and isolation and purification of OLEA, to elucidate the absorption and metabolic pathways of OLEA, and finally, to illustrate the health-promoting properties. Hopefully, this review can promote the use of OLEA in functional foods and therapeutic fields.

Metformin reduces the risk of developing influenza A virus related cardiovascular disease

This study investigated the drug repositioning potential of metformin for cardiovascular risk due to influenza A virus infection. Statistical analysis was performed to analyze factors related to the risk of death after IAV infection in diabetic patients. Through in vitro and in vivo experiments, the effect of metformin on influenza A virus infection in non-diabetic conditions was analyzed. In logistic regression analysis, influenza vaccination (OR = 0.378, p-value = 0.007, 0.186 < 95% C·I < 0.768) and metformin treatment (OR = 0.380, p-value = 0.016, 0.173 < 95% C·I < 0.835) were associated with a decreased influenza-related mortality in diabetic patients. In vitro and in vivo studies showed that viral replication and influenza A virus-induced cytokine expression were inhibited by metformin. In particular, MCP-1 and IP-10, cytokines related to cell infiltration and cardiovascular disease development, were significantly reduced by metformin under influenza A virus infection condition. As a result, the acute exacerbation of atherosclerosis caused by influenza A virus in mouse aorta was inhibited by metformin. In addition, we found that regulation of AKT/MAPK signaling plays an important role in the mechanism of metformin. In conclusion, we demonstrated the potential and mechanism of metformin as a treatment for acute exacerbation of atherosclerosis caused by influenza A virus infection.

Bromocriptine-QR Therapy Reduces Sympathetic Tone and Ameliorates a Pro-Oxidative/Pro-Inflammatory Phenotype in Peripheral Blood Mononuclear Cells and Plasma of Type 2 Diabetes Subjects

Bromocriptine-QR is a sympatholytic dopamine D2 agonist for the treatment of type 2 diabetes that has demonstrated rapid (within 1 year) substantial reductions in adverse cardiovascular events in this population by as yet incompletely delineated mechanisms. However, a chronic state of elevated sympathetic nervous system activity and central hypodopaminergic function has been demonstrated to potentiate an immune system pro-oxidative/pro-inflammatory condition and this immune phenotype is known to contribute significantly to the advancement of cardiovascular disease (CVD). Therefore, the possibility exists that bromocriptine-QR therapy may reduce adverse cardiovascular events in type 2 diabetes subjects via attenuation of this underlying chronic pro-oxidative/pro-inflammatory state. The present study was undertaken to assess the impact of bromocriptine-QR on a wide range of immune pro-oxidative/pro-inflammatory biochemical pathways and genes known to be operative in the genesis and progression of CVD. Inflammatory peripheral blood mononuclear cell biology is both a significant contributor to cardiovascular disease and also a marker of the body’s systemic pro-inflammatory status. Therefore, this study investigated the effects of 4-month circadian-timed (within 2 h of waking in the morning) bromocriptine-QR therapy (3.2 mg/day) in type 2 diabetes subjects whose glycemia was not optimally controlled on the glucagon-like peptide 1 receptor agonist on (i) gene expression status (via qPCR) of a wide array of mononuclear cell pro-oxidative/pro-inflammatory genes known to participate in the genesis and progression of CVD (OXR1, NRF2, NQO1, SOD1, SOD2, CAT, GSR, GPX1, GPX4, GCH1, HMOX1, BiP, EIF2α, ATF4, PERK, XBP1, ATF6, CHOP, GSK3β, NFkB, TXNIP, PIN1, BECN1, TLR2, TLR4, TLR10, MAPK8, NLRP3, CCR2, GCR, L-selectin, VCAM1, ICAM1) and (ii) humoral measures of sympathetic tone (norepinephrine and normetanephrine), whole-body oxidative stress (nitrotyrosine, TBARS), and pro-inflammatory factors (IL-1β, IL-6, IL-18, MCP-1, prolactin, C-reactive protein [CRP]). Relative to pre-treatment status, 4 months of bromocriptine-QR therapy resulted in significant reductions of mRNA levels in PBMC endoplasmic reticulum stress-unfolded protein response effectors [GRP78/BiP (34%), EIF2α (32%), ATF4 (29%), XBP1 (25%), PIN1 (14%), BECN1 (23%)], oxidative stress response proteins [OXR1 (31%), NRF2 (32%), NQO1 (39%), SOD1 (52%), CAT (26%), GPX1 (33%), GPX4 (31%), GCH1 (30%), HMOX1 (40%)], mRNA levels of TLR pro-inflammatory pathway proteins [TLR2 (46%), TLR4 (20%), GSK3β (19%), NFkB (33%), TXNIP (18%), NLRP3 (32%), CCR2 (24%), GCR (28%)], mRNA levels of pro-inflammatory cellular receptor proteins CCR2 and GCR by 24% and 28%, and adhesion molecule proteins L-selectin (35%) and VCAM1 (24%). Relative to baseline, bromocriptine-QR therapy also significantly reduced plasma levels of norepinephrine and normetanephrine by 33% and 22%, respectively, plasma pro-oxidative markers nitrotyrosine and TBARS by 13% and 10%, respectively, and pro-inflammatory factors IL-18, MCP1, IL-1β, prolactin, and CRP by 21%,13%, 12%, 42%, and 45%, respectively. These findings suggest a unique role for circadian-timed bromocriptine-QR sympatholytic dopamine agonist therapy in reducing systemic low-grade sterile inflammation to thereby reduce cardiovascular disease risk.

Towards Better Drug Repositioning: Targeted Immunoinflammatory Therapy for Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common and important microvascular complications of diabetes mellitus (DM). The main clinical features of DN are proteinuria and a progressive decline in renal function, which are associated with structural and functional changes in the kidney. The pathogenesis of DN is multifactorial, including genetic, metabolic, and haemodynamic factors, which can trigger a sequence of events. Controlling metabolic risks such as hyperglycaemia, hypertension, and dyslipidaemia is not enough to slow the progression of DN. Recent studies emphasized immunoinflammation as a critical pathogenic factor in the progression of DN. Therefore, targeting inflammation is considered a potential and novel treatment strategy for DN. In this review, we will briefly introduce the inflammatory process of DN and discuss the anti-inflammatory effects of antidiabetic drugs when treating DN.

Monocyte chemoattractant protein-1 (MCP-1/CCL2) in diabetic retinopathy: latest evidence and clinical considerations

Diabetic retinopathy (DR) is considered as a diabetes-related complication that can render severe visual impairments and is also a risk factor for acquired blindness in both developed as well as developing countries. Through fibrovascular epiretinal membranes (ERMs), this condition can similarly lead to tractional retinal detachment. Laboratory efforts evaluating the DR pathogenesis can be provided by ocular vitreous fluid and ERMs resulting from vitrectomy. The clinical stages of DR are significantly associated with expression levels of certain chemokines, including monocyte chemotactic protein-1 (MCP-1) in the intraocular fluid. The MCP-1 is also a known potent chemotactic factor for monocytes and macrophages that can stimulate them to produce superoxide and other mediators. Following hyperglycemia, retinal pigmented epithelial (RPE) cells, endothelial cells, and Müller's glial cells are of utmost importance for MCP-1 production, and vitreous MCP-1 levels rise in patients with DR. Increased expression of the MCP-1 in the eyes can also play a significant role in the pathogenesis of DR. In this review, current clinical and laboratory progress achieved on the MCP-1 and the DR concerning neovascularization and inflammatory responses in vitreous and/or aqueous humor of DR patients was summarized. It was suggested that further exploration of the MCP-1/CCR2 axis association between clinical stages of DR and expression levels of inflammatory and angiogenic cytokines and chemokines, principally the MCP-1 might lead to potential therapies aiming at neutralizing antibodies and viral vectors.

Effect of high glucose on cytokine production by human peripheral blood immune cells and type I interferon signaling in monocytes: Implications for the role of hyperglycemia in the diabetes inflammatory process and host defense against infection

The major metabolic feature of diabetes is hyperglycemia which has been linked to the diabetes inflammatory processes, and diabetes-related vulnerability to infection. In the present study, we assessed how glucose affected PBMCs in type I interferon (IFN) production and subsequent signaling. We found that the moderately elevated glucose promoted, and high glucose suppressed type I IFN production, respectively. Pre-exposure to high glucose rendered monocytes more sensitive to IFN-α stimulation with heightened signaling, whereas, instantaneous addition of high glucose did not exhibit such effect. Consistent with this finding, the mRNA levels of IFN-α-induced IRF-7 in PBMCs were positively correlated with HbA1c levels of diabetes patients. Additionally, we found that high glucose promoted the production of other proinflammatory cytokines/chemokines. This study suggests that hyperglycemia may affect the inflammatory process in diabetes via promoting proinflammatory cytokines, as well as the host defense against microbial infections through impeding type I IFN production and signaling.

A possible association between the -2518 A>G MCP-1 polymorphism and insulin resistance in school children

Objective Monocyte chemoattractant protein 1 (MCP-1) has been suggested to be involved in the pathophysiology of insulin resistance (IR); therefore, variants in the MCP-1 gene may contribute to the development of this disease. The aim of this study was to analyze the relationship of the -2518 A>G MCP-1 (rs1024611) gene polymorphism with insulin resistance in Mexican children. Subjects and methods A cross-sectional study was performed in 174 children, including 117 children without insulin resistance and 57 children with IR, with an age range of 6-11 years. Levels for serum insulin and high-sensitivity C-reactive protein were determined. The -2518 A>G MCP-1 polymorphism was identified by the polymerase chain reaction-restriction fragment length polymorphism method. Insulin resistance was defined as a HOMA-IR in the upper 75th percentile, which was ≥ 2.4 for all children. Results Genotype frequencies of the rs1024611 polymorphism for the insulin-sensitive group were 17% AA, 48% AG and 35% GG, and the frequency of G allele was 59%, whereas frequencies for the insulin-resistant group were 12% AA, 37% AG and 51% GG, and the frequency of G allele was 69%. The genotype and allele frequencies between groups did not show significant differences. However, the GG genotype was the most frequent in children with IR. The GG genotype was associated with insulin resistance (OR = 2.2, P = 0.03) in a genetic model. Conclusion The -2518 A>G MCP-1 gene polymorphism may be related to the development of insulin resistance in Mexican children.

Association between monocyte chemoattractant protein-1 and blood pressure in smokers

Objective

The expression level of monocyte chemoattractant protein-1 (MCP-1) is increased in atherosclerotic regions, inducing monocyte migration to the blood vessel wall. Although the serum MCP-1 concentration is higher in patients with than without cardiovascular disease, the precise correlations between the serum MCP-1 concentration and factors associated with smoking and atherosclerosis are unknown.

Methods

The serum MCP-1 concentration was measured using an enzyme-linked immunosorbent assay in 207 consecutive smokers who visited our smoking cessation clinic.

Results

Sex-adjusted analysis of smokers revealed that the MCP-1 concentration was positively correlated with age (β = 0.311), smoking duration (β = 0.342), systolic blood pressure (β = 0.225), and diastolic blood pressure (β = 0.137) but not with the body mass index. Multivariate regression analysis showed that smoking duration and systolic blood pressure were independent determinants of the MCP-1 concentration.

Conclusions

The MCP-1 concentration was positively correlated with blood pressure among smokers. Long-term smokers with high blood pressure may be more susceptible to plaque rupture at atherosclerotic lesion sites.

The interaction of auraptene and other oxyprenylated phenylpropanoids with glucose transporter type 4

BACKGROUND

Glucose transporter 4 (GLUT4) is firmly established to play a pivotal role in glucose metabolism and in particular in modulating the insulin-stimulated glucose transport in several tissues, such as skeletal muscle and adipose tissue. Stimulation of GLUT4 by insulin results in its translocation to the plasma membrane, activation of several kinases, and finally in a large glucose influx into cells.

PURPOSE

In this study we investigated the modulating properties of four biologically active oxyprenylated ferulic acid and umbelliferone derivatives and of their unprenylated parent compounds on GLUT-4 mediated glucose uptake and translocation.

METHODS

Oxyprenylated phenylpropanoids have been synthesized in high yields and purity by already reported methodologies. All the synthesized chemicals were tested for their capacity to modulate GLUT4 mediated glucose uptake and GLUT4 translocation in L6 rat skeletal myoblasts in the concentration range 0.1 - 10 µM. Insulin (0.1 µM) was used as positive control. Western blot analysis was employed to assess if GLUT4 translocation occurred prior to increase of glucose uptake. Statistical analyses were carried out by the Dunnett multiple comparison test.

RESULTS

4'-Geranyloxyferulic acid (GOFA), 7-isopentenyloxycoumarin, and auraptene (7-geranyloxycoumarin) increased glucose uptake in a concentration-dependent manner, and significant increases were observed at 0.1 µM for GOFA, and 10 µM for 7-isopentenyloxycoumarin, and auraptene. These products also were able to significantly promote the translocation of GLUT4 to the plasma membrane of L6 myotubes. After treatment with compounds for 15 min, the incorporated amounts of GOFA, 7-isopentenyloxucoumarin, and auraptene were 0.15, 0.32, and 1.77 nmols/60-mm culture dish, respectively. A sample of raw Italian propolis, found to be rich in GOFA and auraptene, was also seen to mimic insulin-effect in the concentration range 0.01 - 1.0 mg/ml.

CONCLUSIONS

Among the compounds assayed, auraptene showed to possess potentialities to be a potent activator of both translocation of GLUT4 and glucose influx into skeletal muscle cells with the highest bioavailability among effective compounds. Its capacity to modulate sugar metabolism, coupled to its presence in edible Citrus fruits, can be regarded as an additional reason to account for the already known stimulating properties of some vegetable (e.g. bitter orange).

DL-3-n-butylphthalide protects endothelial cells against advanced glycation end product-induced injury by attenuating oxidative stress and inflammation responses

Endothelial dysfunction, regarded as a key step in the pathophysiological course of diabetic vascular complications, is initiated and deteriorated by advanced glycation end products (AGEs). DL-3-n-butylphthalide (DL-NBP) has been proven to have protective effects on neurons and vascular endothelial cells against ischemic and anoxic damage. The aim of the present study was to investigate whether NBP is able to attenuate AGE-induced endothelial dysfunction in vitro, and also elucidate the possible underlying mechanism. An injury model of human umbilical vein endothelial cells (HUVECs) induced by AGEs (200 µg/ml) was established. The results demonstrated that pretreatment with NBP (1-100 µM) significantly increased HUVEC viability and inhibited the apoptosis induced by AGEs. In addition, AGEs stimulated the expression levels of the receptor for AGEs protein and the downstream protein nuclear factor-κB in HUVECs, which were inhibited by pretreatment with NBP. Furthermore, it significantly reduced reactive oxygen species generation and the level of the inflammatory cytokines, intercellular cell adhesion molecule-1 and monocyte chemotactic protein-1, in HUVECs mediated by AGEs. The current findings indicated that NBP attenuated AGE-induced endothelial dysfunction by ameliorating inflammation and oxidative stress responses.

Intraocular soluble intracellular adhesion molecule-1 correlates with subretinal fluid height of diabetic macular edema

Objective:

To investigate the correlations between aqueous concentrations of vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), soluble intracellular adhesion molecule-1 (sICAM-1) and diabetic macular edema (DME).

Materials and Methods:

VEGF, MCP-1 and sICAM-1 concentrations in aqueous humor samples of 22 patients with DME and 23 patients with cataract of a control group were measured with solid-phase chemiluminescence immunoassay.

Results:

Aqueous VEGF (89.2 ± 58.5 pg/ml versus 48.5 ± 27.8 pg/ml, P = 0.006), MCP-1 (684.2 ± 423.4 pg/ml versus 432.4 ± 230.4 pg/ml, P = 0.019) and sICAM-1 (3213.8 ± 2581.6 pg/ml versus 260.2 ± 212.2 pg/ml, P < 0.001) all vary significantly between DME group and control group. Maximum height of submacular fluid measured by Optical coherence tomography (OCT) was significantly associated with aqueous sICAM-1 (r = -0.45, P = 0.034). The maximum height of macular thickness measured by OCT was not significantly associated with either VEGF (P = 0.300), MCP-1 (P = 0.320) or sICAM-1 (P = 0.285).

Conclusions:

Our results suggest that sICAM-1 may majorly contribute to the formation of subretinal fluid in DME patients and imply that MCP-1 and sICAM-1 may be the potential therapy targets, besides VEGF.

Serum monocyte chemoattractant protein-1 is a biomarker in patients with diabetes and periodontitis

INTRODUCTION

The role of serum Monocyte Chemoattractant Protein-1 (MCP-1) as a biomarker of periodontitis is well documented; however, its role in diabetic patients with periodontitis is unknown.

AIM

This study was conducted to determine the presence and concentration of serum MCP-1 in diabetic patients with and without periodontitis and correlate it glycemic status with periodontitis.

MATERIALS AND METHODS

Adult diabetic patients were enrolled and grouped into group I, II, and III based on their glycemic status and serum MCP-1 estimated by ELISA. Linear regression and correlation tests were performed using R statistical software, Medcalc software to observe correlation between the serum MCP-1 and glycated hemoglobin level among different groups.

RESULTS

Serum samples obtained from 37 patients tested positive for MCP-1. Mean serum MCP-1 concentration was highest (482.3 pg/ml) in group III, lowest (149.3 pg/ml) in group I, and intermediate 398.8 pg/ml in group II. Correlation and regression analysis was done between HbA1c and serum MCP-1. A significant positive correlation (P < 0.001) was observed. Serum MCP-1 increased by 37.278 pg/ml for every 1% rise in HbA1c, and the levels were raised in group II and group III than in group I irrespective of their glycemic status. With an HbA1c range of 6.5-6.9% (group II), the serum MCP-1 values cluster around 380-410 pg/ml. Elevated levels of serum MCP-1 (>500 pg/ml) in three subjects corresponded to HbA1c values more than 12.2% (group III).

CONCLUSION

To our knowledge, this is the first study to document serum MCP-1 levels in diabetic patients with periodontitis. Glycemic status influences serum MCP-1, and lack of glycemic control contributes to increased serum MCP-1 levels. Serum MCP-1 may thus serve as a biomarker of inflammation and disease progression in diabetes with periodontitis.

Influence of Egr-1 in cardiac tissue-derived mesenchymal stem cells in response to glucose variations

Mesenchymal stem cells (MSCs) represent a promising cell population for cell therapy and regenerative medicine applications. However, how variations in glucose are perceived by MSC pool is still unclear. Since, glucose metabolism is cell type and tissue dependent, this must be considered when MSCs are derived from alternative sources such as the heart. The zinc finger transcription factor Egr-1 is an important early response gene, likely to play a key role in the glucose-induced response. Our aim was to investigate how short-term changes in in vitro glucose concentrations affect multipotent cardiac tissue-derived MSCs (cMSCs) in a mouse model of Egr-1 KO (Egr-1^−/−). Results showed that loss of Egr-1 does not significantly influence cMSC proliferation. In contrast, responses to glucose variations were observed in wt but not in Egr-1^−/− cMSCs by clonogenic assay. Phenotype analysis by RT-PCR showed that cMSCs Egr-1^−/− lost the ability to regulate the glucose transporters GLUT-1 and GLUT-4 and, as expected, the Egr-1 target genes VEGF, TGFβ-1, and p300. Acetylated protein levels of H3 histone were impaired in Egr-1^−/− compared to wt cMSCs. We propose that Egr-1 acts as immediate glucose biological sensor in cMSCs after a short period of stimuli, likely inducing epigenetic modifications.

Effects of Saskatoon berry powder on monocyte adhesion to vascular wall of leptin receptor-deficient diabetic mice

HYPOTHESIS

Atherosclerotic cardiovascular complications are the leading cause of death in diabetic patients. Monocyte adhesion is an early event for atherogenesis. Previous studies demonstrated that dark-skin berries had cardiovascular protective effects. We hypothesize that Saskatoon berry (SB) powder may reduce monocyte adhesion in leptin receptor-deficient (db/db) diabetic mice.

METHODS

Wild-type and db/db mice were fed with chow or supplemented with SB powder. Anthocyanins in SB powder were identified using mass spectrometry. Mouse monocytes were incubated with mouse aorta. Monocyte adhesion was counted under microscopy. Inflammatory or metabolic markers in blood or tissue were analyzed using immunological or biochemical methods.

RESULTS

SB powder significantly reduced monocyte adhesion to aorta from diabetic db/db mice compared to regular chow. The increased monocyte adhesion to aorta was normalized in db/db mice treated with ≥5% of SB powder for 4 weeks. Increased contents of Nicotinamide adenine dinucleotide phosphate oxidase (NADPH) oxidase-4, heat shock factor-1, monocyte chemotactic protein (MCP)-1, intracellular adhesion molecule (ICAM)-1, P-selectin, tumor necrosis factor-α, plasminogen activator inhibitor (PAI)-1 and urokinase plasminogen activator in aorta or heart apex, elevated plasma PAI-1 and MCP-1 were detected in db/db mice on chow compared to wild-type mice on the same diet; 5% SB powder inhibited the increases of inflammatory, fibrinolytic or stress regulators in aorta or heart apex of db/db mice. Monocyte adhesion positively correlated with blood glucose, cholesterol, body weight, heart MCP-1, PAI-1 or ICAM-1.

CONCLUSION

The findings suggest that SB powder attenuated monocyte adhesion to aorta of db/db mice, which was potentially mediated through inhibiting the inflammatory, stress and/or fibrinolyic regulators.

Involvement of fibrinolytic regulators in adhesion of monocytes to vascular endothelial cells induced by glycated LDL and to aorta from diabetic mice

Diabetes mellitus accelerates the development of atherosclerotic cardiovascular diseases. Monocyte adhesion is an early cellular event of atherogenesis. Elevated levels of glyLDL were common in diabetic patients. Our previous studies indicated that HSF1 and p22-phox (a subunit of the NOX complex) were involved in glyLDL-induced up-regulation of PAI-1 in vascular EC. The present study demonstrated that glyLDL significantly increased the adhesion of monocytes to the surface of cultured human umbilical vein or PAEC. Transfection of siRNA for PAI-1, p22-phox, or HSF1 in EC prevented glyLDL-induced monocyte adhesion to EC. uPA siRNA increased monocyte adhesion to EC. Exogenous uPA reduced monocyte adhesion induced by glyLDL or uPA siRNA. Exogenous PAI-1 restored monocyte adhesion to EC inhibited by PAI-1 siRNA or uPA. GlyLDL-induced monocyte adhesion to EC was inhibited by treatment of EC with RAP, an antagonist for LRP, and enhanced by uPAR antibody. The adhesion of monocytes to aorta from leptin db/db diabetic mice was significantly greater than to that from control mice, which was associated with elevated contents of PAI-1, uPA, p22-phox, and HSF1 in hearts of db/db mice. The results suggest that oxidative stress and fibrinolytic regulators (PAI-1, uPA, and uPAR) are implicated in the modulation of glyLDL-induced monocyte adhesion to vascular endothelium, which may play a crucial role in vascular inflammation under diabetes-associated metabolic disorder.

Norepinephrine increases NADPH oxidase-derived superoxide in human peripheral blood mononuclear cells via α-adrenergic receptors

Many diseases associated with sympathoexcitation also exhibit elevated reactive oxygen species (ROS). A recent animal study indicated that exogenous administration of the sympathetic neurotransmitter norepinephrine (NE) increased systemic ROS via circulating leukocytes. The mechanisms contributing to this effect of NE and whether these findings can be translated to humans is unknown. Thus we tested the hypothesis that NE increases superoxide production in human peripheral blood mononuclear cells (PBMCs) via NADPH oxidase. Primary human PBMCs were freshly isolated from healthy young men and placed in culture. After NE (50 pg/ml, 50 ng/ml, and 50 μg/ml concentrations) or control treatments, NADPH oxidase mRNA expression (gp91(phox), p22(phox), and p67(phox)) was assessed using real-time RT-PCR, and intracellular superoxide production was measured using dihydroethidium fluorescence. PBMCs were also treated with selective adrenergic agonists-antagonists to determine the receptor population involved. In addition, CD14(+) monocyte-endothelial cell adhesion was determined using a fluorescent-based assay. NE significantly increased NADPH oxidase gene expression and intracellular superoxide production in a time-dependent manner (superoxide: 0.9 ± 0.2 fold, 6 h vs. 3.0 ± 0.3 fold, 36 h; NE, 50 μg/ml; P < 0.05). The sustained increase in NE-induced superoxide production was primarily mediated via α-adrenergic receptors, preferentially α2-receptors. The NADPH oxidase blocker diphenylene iodonium and protein kinase C inhibitor Staurosporine significantly attenuated NE-induced increases in superoxide production. Importantly, NE treatment increased CD14(+) monocyte-endothelial cell adhesion. These findings indicate for the first time that NE increases superoxide production in freshly isolated primary human PBMCs via NADPH oxidase through α-adrenergic receptors, an effect facilitating monocyte adhesion to the endothelium.

Effect of different degrees of impaired glucose metabolism on the expression of inflammatory markers in monocytes of patients with atherosclerosis

Inflammatory markers are elevated in type 2 diabetic patients (DP) and may predict the development of type 2 diabetes. Our aims were to analyze differences in the expression of inflammatory and immunological molecules between DP and healthy subjects and to investigate whether glycemic control might prevent the overexpression of inflammatory markers in DP. Twenty-two DP with advanced atherosclerosis and eight healthy blood donors were included. DP were classified as well (HbA1c ≤ 6.5) or poorly controlled (HbA1c > 6.5). In "in vitro" studies, monocytes were exposed to low (5.5 mM) or high glucose (26 mM) concentrations in the absence or presence of insulin. Expression profiling of 14 inflammatory genes was analyzed using TLDA analysis. "In vivo" results show that monocytes from DP had increased levels of monocyte chemoattractant protein (MCP-1) and interleukin 6 (IL6) and lower levels of Toll-like receptor 2 (TLR2) mRNA than healthy subjects. Well-controlled DP had lower levels of IL-6 than poorly controlled DP, suggesting that glycemic control may prevent IL6 mRNA alterations associated with diabetes. "In vitro" results demonstrate that glucose directly and significantly induced MCP-1 and IL6 and reduced TLR2 mRNA expression. Insulin at high dose (100 IU/ml) dramatically enhanced the upregulatory effects of glucose on MCP-1 and IL-6 and reduced per se TLR2 mRNA expression. MCP-1, IL-6 and TLR2 are key inflammatory players altered in monocytes from type 2 DP. Both hyperinsulinemia and hyperglycemia contribute to alter the expression of these genes. The glycemic control only significantly prevented IL6 overexpression in this group of patients.

The flame-retardant BDE-99 dose-dependently affects viral replication in CVB3-infected mice

The flame retardant component 2,2',4,4',5-penta-BDE (BDE-99) is found in the environment and in human tissues and fluids. In mice the common human coxsackievirus B3 (CVB3) infection has been shown to change the tissue distribution of BDE-99. We now investigate how CVB3 infection in mice affects liver uptake of (14)C at two doses of radiolabelled BDE-99, and whether increased tissue levels are related to changed virus replication and gene expression of the proinflammatory chemokine monocyte chemoattractant protein-1 (MCP-1). Mice were infected on day 0, orally treated either with 200μg or 20mg (14)C-BDE-99/kgbw on day 1, and euthanised on day 3. Serum and liver levels of (14)C-BDE-99, as well as virus levels and gene expressions of MCP-1 in the liver, were measured. In non-infected mice, there was a dose-dependent uptake of BDE-99 in both liver and serum, and in infected animals the liver BDE-99 levels was further increased. When comparing infected mice exposed to the two BDE-99 doses, the higher BDE dose resulted in increased virus amounts in the liver, and decreased infection-induced expression of MCP-1. Consequently, a high enough dose/tissue concentration of BDE-99 may result in a disturbed mobilisation of immune cells into infected tissues that could explain higher virus titres and a possibly altered clinical course of the disease. Moreover, the fact that CVB3 infection increased the BDE-99 levels in liver but not in serum may impair the risk assessment of polybrominated diphenyl ethers (PBDEs) in subclinical and clinically infected individuals, as serum levels is the common marker of exposure.

Inhibition of apelin expression switches endothelial cells from proliferative to mature state in pathological retinal angiogenesis

The recruitment of mural cells such as pericytes to patent vessels with an endothelial lumen is a key factor for the maturation of blood vessels and the prevention of hemorrhage in pathological angiogenesis. To date, our understanding of the specific trigger underlying the transition from cell growth to the maturation phase remains incomplete. Since rapid endothelial cell growth causes pericyte loss, we hypothesized that suppression of endothelial growth factors would both promote pericyte recruitment, in addition to inhibiting pathological angiogenesis. Here, we demonstrate that targeted knockdown of apelin in endothelial cells using siRNA induced the expression of monocyte chemoattractant protein-1 (MCP-1) through activation of Smad3, via suppression of the PI3K/Akt pathway. The conditioned medium of endothelial cells treated with apelin siRNA enhanced the migration of vascular smooth muscle cells, through MCP-1 and its receptor pathway. Moreover, in vivo delivery of siRNA targeting apelin, which causes exuberant endothelial cell proliferation and pathological angiogenesis through its receptor APJ, led to increased pericyte coverage and suppressed pathological angiogenesis in an oxygen-induced retinopathy model. These data demonstrate that apelin is not only a potent endothelial growth factor, but also restricts pericyte recruitment, establishing a new connection between endothelial cell proliferation signaling and a trigger of mural recruitment.

Burkholderia pseudomallei triggers altered inflammatory profiles in a whole-blood model of type 2 diabetes-melioidosis comorbidity

Melioidosis is a potentially fatal disease caused by the bacterium Burkholderia pseudomallei. Type 2 diabetes (T2D) is the most common comorbidity associated with melioidosis. B. pseudomallei isolates from melioidosis patients with T2D are less virulent in animal models than those from patients with melioidosis and no identifiable risk factors. We developed an ex vivo whole-blood assay as a tool for comparison of early inflammatory profiles generated by T2D and nondiabetic (ND) individuals in response to a B. pseudomallei strain of low virulence. Peripheral blood from individuals with T2D, with either poorly controlled glycemia (PC-T2D [n = 6]) or well-controlled glycemia (WC-T2D [n = 8]), and healthy ND (n = 13) individuals was stimulated with B. pseudomallei. Oxidative burst, myeloperoxidase (MPO) release, expression of pathogen recognition receptors (TLR2, TLR4, and CD14), and activation markers (CD11b and HLA-DR) were measured on polymorphonuclear (PMN) leukocytes and monocytes. Concentrations of plasma inflammatory cytokine (interleukin-6 [IL-6], IL-12p70, tumor necrosis factor alpha [TNF-α], monocyte chemoattractant protein 1 [MCP-1], IL-8, IL-1β, and IL-10) were also determined. Following stimulation, oxidative burst and MPO levels were significantly elevated in blood from PC-T2D subjects compared to controls. Differences were also observed in expression of Toll-like receptor 2 (TLR2), CD14, and CD11b on phagocytes from T2D and ND individuals. Levels of IL-12p70, MCP-1, and IL-8 were significantly elevated in blood from PC-T2D subjects compared to ND individuals. Notably, differential inflammatory responses of PC-T2D, WC-T2D, and ND individuals to B. pseudomallei occur independently of bacterial load and confirm the efficacy of this model of T2D-melioidosis comorbidity as a tool for investigation of dysregulated PMN and monocyte responses to B. pseudomallei underlying susceptibility of T2D individuals to melioidosis.

Effects of dietary glutamine on inflammatory mediator gene expressions in rats with streptozotocin-induced diabetes

OBJECTIVES

This study investigated the effects of glutamine (Gln) supplementation on gene expressions of inflammatory mediators and cytokines associated with T-helper cell type 17 (Th17) regulation in diabetic rats.

METHODS

There were one normal control group and two diabetic groups in this study. Rats in the normal control group were fed a regular chow diet. One diabetic group (DM) was fed a common semipurified diet, and the other diabetic group received a diet in which part of the casein was replaced by Gln (DM-Gln), which provided 25% of the total amino acid nitrogen for 8 wk. Diabetes was induced by an intraperitoneal injection of nicotinamide followed by streptozotocin. Rats with blood glucose levels exceeding 200 mg/dL were considered diabetic. Blood samples and blood mononuclear cells of the animals were collected at the end of the study for further analysis.

RESULTS

Gene expressions of transforming growth factor-β1 and interleukin-17A did not differ in blood mononuclear cells among the three groups. Expressions of interleukin-6, interleukin-23, monocyte chemotactic protein-1, and the receptor of the advanced glycated endproducts gene were higher in blood mononuclear cells and the ratio of reduced to oxidized glutathione was lower in erythrocytes in the DM group than in the normal control group. Messenger RNA expressions of these genes were lower, whereas the ratio of reduced to oxidized glutathione was higher in the DM-Gln group than in the DM group.

CONCLUSION

Supplemental dietary Gln increased the antioxidant potential and downregulated the expressions of inflammatory mediators. However, Th17 might not be an important involved pathway and the regulatory effect of Gln on Th17 immune response was not obvious in this animal model.

Encapsulating peritoneal sclerosis: what have we learned?

Encapsulating peritoneal sclerosis (EPS) is a rare complication of peritoneal dialysis (PD), but carries significant morbidity and mortality. We review the clinical features and radiologic and histologic changes found at diagnosis of EPS. Although EPS is strongly associated with the duration of PD, the pathogenesis remains only partly understood. We discuss the mechanisms thought to underlie the abnormally thickened, sclerotic peritoneal membrane seen in long-term PD patients including epithelial to mesenchymal transition and the molecular mediators of fibrosis and angiogenesis. We review how exposure to high-glucose, nonphysiological dialysis fluids, peritonitis, and uremia may be responsible for these changes. Much remains to be learned about optimal management of EPS, both medical and surgical, because the literature lacks controlled studies. Future research challenges include defining the role of surgery, immunosuppression, and antifibrotic agents in the management of EPS. We also need to understand why some patients progress from asymptomatic peritoneal sclerosis to the extreme levels of fibrin deposition and bowel encapsulation seen in EPS. Screening PD patients for potential future EPS remains difficult, and we need strategies for monitoring patients on longer-term PD that enable us to better quantify the risk of EPS for the individual patient.

A common polymorphism in the monocyte chemoattractant protein-1 (MCP-1) gene regulatory region influences MCP-1 expression and function of isolated human pancreatic islets

BACKGROUND AND AIMS

Islet transplantation is an attractive approach to treat type 1 diabetic patients. However, suboptimal islet engraftment still represents an unsolved problem. It has been shown that human islets release monocyte chemoattractant protein-1 (MCP-1), one of the most powerful macrophage chemokines, which may impair the fate of the transplant. The aim of this study was to evaluate the presence and role of MCP-1 in isolated human islets, including genotyping for a common polymorphism.

METHODS

Pancreatic islets were isolated by enzymatic digestion and gradient purification from 41 nondiabetic multiorgan donors. We measured MCP-1 mRNA expression by quantitative real- time reverse-transcriptase polymerization chain reaction, analyzed the MCP-1 single nucleotide polymorphism, -2518 G/A (SNP, rs 1024611) and evaluated glucose-stimulated insulin release (IR; microU/islet/min).

RESULTS

MCP-1 mRNA expression was found in all studied batches of islets. Overall, IR was significantly higher at 16.7 mmol/L than 3.3 mmol/L glucose. We observed a significant negative correlation between MCP-1 mRNA expression and stimulation index (SI). We found that MCP-1 mRNA expression was significantly higher in CC and CT compared with TT genotype groups. Finally, SI was significant lower in the CC with respect to the TT genotype group.

CONCLUSIONS

These data show that MCP-1 gene expression regulated by the -2518 G/A polymorphism, is correlated with glucose-stimulated insulin release. The study of MCP-1 expression and genotype on isolated islets before transplantation may be useful to understand the inflammatory response after infusion of human islets into patients with type 1 diabetes mellitus.

Atherogenic factors and their epigenetic relationships

Hypercholesterolemia, homocysteine, oxidative stress, and hyperglycemia have been recognized as the major risk factors for atherogenesis. Their impact on the physiology and biochemistry of vascular cells has been widely demonstrated for the last century. However, the recent discovery of the role of epigenetics in human disease has opened up a new field in the study of atherogenic factors. Thus, epigenetic tags in endothelial, smooth muscle, and immune cells seem to be differentially affected by similar atherogenic stimuli. This paper summarizes some recent works on expression of histone-modifying enzymes and DNA methylation directly linked to the presence of risk factors that could lead to the development or prevention of the atherosclerotic process.

Increased levels of CRP and MCP-1 are associated with previously unknown abnormal glucose regulation in patients with acute STEMI: a cohort study

BACKGROUND

Inflammation plays an important role in the pathophysiology of both atherosclerosis and type 2 diabetes and some inflammatory markers may also predict the risk of developing type 2 diabetes. The aims of the present study were to assess a potential association between circulating levels of inflammatory markers and hyperglycaemia measured during an acute ST-elevation myocardial infarction (STEMI) in patients without known diabetes, and to determine whether circulating levels of inflammatory markers measured early after an acute STEMI, were associated with the presence of abnormal glucose regulation classified by an oral glucose tolerance test (OGTT) at three-month follow-up in the same cohort.

METHODS

Inflammatory markers were measured in fasting blood samples from 201 stable patients at a median time of 16.5 hours after a primary percutaneous coronary intervention (PCI). Three months later the patients performed a standardised OGTT. The term abnormal glucose regulation was defined as the sum of the three pathological glucose categories classified according to the WHO criteria (patients with abnormal glucose regulation, n = 50).

RESULTS

No association was found between inflammatory markers and hyperglycaemia measured during the acute STEMI. However, the levels of C-reactive protein (CRP) and monocyte chemoattractant protein-1 (MCP-1) measured in-hospital were higher in patients classified three months later as having abnormal compared to normal glucose regulation (p = 0.031 and p = 0.016, respectively). High levels of CRP (≥ 75 percentiles (33.13 mg/L)) and MCP-1 (≥ 25 percentiles (190 ug/mL)) were associated with abnormal glucose regulation with an adjusted OR of 3.2 (95% CI 1.5, 6.8) and 7.6 (95% CI 1.7, 34.2), respectively.

CONCLUSION

Elevated levels of CRP and MCP-1 measured in patients early after an acute STEMI were associated with abnormal glucose regulation classified by an OGTT at three-month follow-up. No significant associations were observed between inflammatory markers and hyperglycaemia measured during the acute STEMI.

Rimonabant-mediated changes in intestinal lipid metabolism and improved renal vascular dysfunction in the JCR:LA-cp rat model of prediabetic metabolic syndrome

Rimonabant (SR141716) is a specific antagonist of the cannabinoid-1 receptor. Activation of the receptor initiates multiple effects on central nervous system function, metabolism, and body weight. The hypothesis that rimonabant has protective effects against vascular disease associated with the metabolic syndrome was tested using JCR:LA-cp rats. JCR:LA-cp rats are obese if they are cp/cp, insulin resistant, and exhibit associated micro- and macrovascular disease with end-stage myocardial and renal disease. Treatment of obese rats with rimonabant (10 mg.kg(-1).day(-1), 12-24 wk of age) caused transient reduction in food intake for 2 wk, without reduction in body weight. However, by 4 wk, there was a modest, sustained reduction in weight gain. Glycemic control improved marginally compared with controls, but at the expense of increased insulin concentration. In contrast, rimonabant normalized fasting plasma triglyceride and reduced plasma plasminogen activator inhibitor-1 and acute phase protein haptoglobin in cp/cp rats. Furthermore, these changes were accompanied by reduced postprandial intestinal lymphatic secretion of apolipoprotein B48, cholesterol, and haptoglobin. While macrovascular dysfunction and ischemic myocardial lesion frequency were unaffected by rimonabant treatment, both microalbuminuria and glomerular sclerosis were substantially reduced. In summary, rimonabant has a modest effect on body weight in freely eating obese rats and markedly reduces plasma triglyceride levels and microvascular disease, in part due to changes in intestinal metabolism, including lymphatic secretion of apolipoprotein B48 and haptoglobin. We conclude that rimonabant improves renal disease and intestinal lipid oversecretion associated with an animal model of the metabolic syndrome that appears to be independent of hyperinsulinemia or macrovascular dysfunction.

Glycemic memory associated epigenetic changes

It is evident that metabolic memory, whereby diabetic complications continue to develop and progress in individuals who returned to normal glycemic control after a period of transient hyperglycemia, can have long lasting effects. We have primary findings that transient hyperglycemia causes profound transcriptional changes in vascular endothelial cells. We hypothesized that ambient hyperglycemia triggers gene-activating events of the NFκB p65 promoter that are mediated by changes in epigenetic modifications. In a follow-up study we identified two histone-specific writing and erasing enzymes involved in the underlying regulation of gene expression during transient hyperglycemia and subsequent return to normoglycemia. Experimental evidence indicates that previous hyperglycemia is associated with persistent expression of the NFκB p65 gene, which activates NFκB-dependent proteins, such as MCP-1, which are implicated in diabetes-associated vascular injury. Increased gene transcription is correspondent with H3K4m1, but not H3K4m2 and H3K4m3, on the NFκB p65 gene. In vascular endothelial cells the histone methyltransferase Set7 can write the mono-methylation mark H3K4m1 and this methyl-writing enzyme is recruited as a gene co-activator in response to glucose. Furthermore, Set7 knockdown prevents glucose-induced p65 expression. We hypothesize that these molecular events represent an integrated response of the epigenome that lead to changes in the expression of genes and proteins that regulate the development and progression of diabetic vascular complications. Further characterisation of these glucose-induced epigenetic events and the identification of key enzymes involved will improve our understanding of the pathways implicated in diabetic vascular injury.

Diabetes impairs arteriogenesis in the peripheral circulation: review of molecular mechanisms

Patients suffering from both diabetes and PAD (peripheral arterial disease) are at risk of developing critical limb ischaemia and ulceration, and potentially requiring limb amputation. In addition, diabetes complicates surgical treatment of PAD and impairs arteriogenesis. Arteriogenesis is defined as the remodelling of pre-existing arterioles into conductance vessels to restore the perfusion distal to the occluded artery. Several strategies to promote arteriogenesis in the peripheral circulation have been devised, but the mechanisms through which diabetes impairs arteriogenesis are poorly understood. The present review provides an overview of the current literature on the deteriorating effects of diabetes on the key players in the arteriogenesis process. Diabetes affects arteriogenesis at a number of levels. First, it elevates vasomotor tone and attenuates sensing of shear stress and the response to vasodilatory stimuli, reducing the recruitment and dilatation of collateral arteries. Secondly, diabetes impairs the downstream signalling of monocytes, without decreasing monocyte attraction. In addition, EPC (endothelial progenitor cell) function is attenuated in diabetes. There is ample evidence that growth factor signalling is impaired in diabetic arteriogenesis. Although these defects could be restored in animal experiments, clinical results have been disappointing. Furthermore, the diabetes-induced impairment of eNOS (endothelial NO synthase) strongly affects outward remodelling, as NO signalling plays a key role in several remodelling processes. Finally, in the structural phase of arteriogenesis, diabetes impairs matrix turnover, smooth muscle cell proliferation and fibroblast migration. The review concludes with suggestions for new and more sophisticated therapeutic approaches for the diabetic population.

Irbesartan-mediated reduction of renal and cardiac damage in insulin resistant JCR : LA-cp rats

BACKGROUND AND PURPOSE

Angiotensin II receptor antagonists (ARBs), originally developed for antihypertensive properties, have pleiotropic effects including direct vascular actions. We tested the hypothesis that the ARB irbesartan would be effective against micro- and macrovascular complications of the prediabetic metabolic syndrome using the obese, insulin-resistant JCR : LA-cp rat that exhibits micro- and macrovascular disease with ischaemic myocardial lesions and renal disease.

EXPERIMENTAL APPROACH

Obese male rats were treated with irbesartan (30 mg.kg(-1).day(-1), incorporated into chow) from 12 to 25 weeks of age.

KEY RESULTS

Irbesartan treatment caused no change in food intake or body weight. Fasting glycaemic control of the JCR : LA-cp rats was marginally improved, at the expense of increased plasma insulin levels ( approximately 50%). Fasting plasma triglycerides were marginally reduced ( approximately 25%), while cholesterol concentrations were unchanged. Elevated concentrations of adiponectin, monocyte chemotactic protein-1 and plasminogen activator inhibitor-1 were reduced along with severity of glomerular sclerosis. Macrovascular dysfunction (aortic hypercontractile response to noradrenergic stimulus and reduced endothelium-dependent relaxation) was improved and frequency of ischaemic myocardial lesions reduced (62%).

CONCLUSIONS AND IMPLICATIONS

Irbesartan reduces markers of inflammation and prothombotic status, improves macrovascular function and reduces glomerular sclerosis and myocardial lesions in a model of the metabolic syndrome. Unlike pharmaceutical agents targeted on metabolic dysfunction, irbesartan reduced end-stage disease without major reduction of plasma lipids or insulin. The protective effects appear to be secondary to unknown intracellular mechanisms, probably involving signal transduction pathways. Understanding these would offer novel pharmaceutical approaches to protection against cardiovascular disease.

The immunobiology of viral arthritides

A large range of human viruses are associated with the development of arthritis or arthralgia. Although there are many parallels with autoimmune arthritides, there is little evidence that viral arthritides lead to autoimmune disease. In humans viral arthritides usually last from weeks to months, can be debilitating, and are usually treated with non-steroidal anti-inflammatory drugs, but with variable success. Viral arthritides likely arise from immunopathological inflammatory responses directed at viruses and/or their products residing and/or replicating within joint tissues. Macrophages recruited by monocyte chemoattractant protein-1 (MCP-1/CCL2) and activated by interferon, and proinflammatory mediators like tumour necrosis factor alpha, interferon gamma, interleukin-6 and interleukin-1beta appear to be common elements in this group of diseases. The challenge for new treatments is to target excessive inflammation without compromising anti-viral immunity. Recent evidence from mouse models suggests targeting MCP-1 or complement may emerge as viable new treatment options for viral arthritides.

Amelioration of alphavirus-induced arthritis and myositis in a mouse model by treatment with bindarit, an inhibitor of monocyte chemotactic proteins

OBJECTIVE

Alphaviruses such as chikungunya virus, Sindbis virus, o'nyong-nyong virus, Mayaro virus, and Ross River virus (RRV), are commonly associated with arthralgias and overt arthritides worldwide. Understanding the processes by which arthritogenic viruses cause disease is a prerequisite in the quest for better treatments. In this regard, we have recently established that monocyte/macrophages are mediators of alphavirus-induced arthritis in mice. We hypothesized that chemokines associated with monocyte/macrophage recruitment may play an important role in disease. The aim of the present investigations was to determine whether bindarit, an inhibitor of monocyte chemotactic protein (MCP) synthesis, could ameliorate alphavirus-induced rheumatic disease in mice.

METHODS

Using our recently developed mouse model of RRV-induced arthritis, which has many characteristics of RRV disease (RRVD) in humans, the effects of bindarit treatment on RRVD in mice were determined via histologic analyses, immunohistochemistry, flow cytometry, real-time polymerase chain reaction analysis, enzyme-linked immunosorbent assay, and electrophoretic mobility shift assay.

RESULTS

Bindarit-treated RRV-infected mice developed mild disease and had substantially reduced tissue destruction and inflammatory cell recruitment as compared with untreated RRV-infected mice. The virus load in the tissues was not affected by bindarit treatment. Bindarit exhibited its activity by down-regulating MCPs, which in turn led to inhibition of cell infiltration and lower production of NF-kappaB and tumor necrosis factor alpha, which are involved in mediating tissue damage.

CONCLUSION

Our data support the use of inhibitors of MCP production in the treatment of arthritogenic alphavirus syndromes and suggest that bindarit may be useful in treating RRVD and other alphavirus-induced arthritides in humans.

Eplerenone does not attenuate diabetes-associated atherosclerosis

BACKGROUND

It has been suggested that aldosterone, with its known pro-inflammatory and profibrotic actions, may play a key role in the development and progression of atherosclerosis.

METHOD

In this study, the ability of aldosterone antagonism to reduce atherosclerosis in experimental diabetes was assessed. Diabetes was induced in ApoE knockout mice with streptozotocin, and the mice were treated with the specific aldosterone antagonist, eplerenone, in their feed over 20 weeks (approximately 200 mg/kg per day).

RESULT

En face analysis revealed that eplerenone treatment was unable to attenuate atherosclerosis as assessed by percentage lesion area quantitation in the aortae of these mice compared with untreated diabetic mice (diabetic, 10.7 +/- 1.1; diabetic + eplerenone, 8.8 +/- 1.2%). In contrast, we observed a significant, more than 50% decrease in percentage of plaque area in the nondiabetic control groups. Despite this lack of effect in the diabetic mice, eplerenone treatment was associated with reduced cytosolic superoxide production. However, aortic transcript levels of key molecules implicated in diabetes-associated atherogenesis, such as monocyte chemoattractant protein-1 and vascular cell adhesion molecule-1, were not significantly attenuated by eplerenone.

CONCLUSION

These findings suggest that eplerenone treatment may not be as antiatherosclerotic in the diabetic context.

Selective inhibition of cytokine-activated extracellular signal-regulated kinase by cyclic AMP via Epac1-dependent induction of suppressor of cytokine signalling-3

Here we demonstrate that elevation of cyclic AMP (cAMP) levels in human umbilical vein endothelial cells (HUVECs) specifically attenuates ERK1,2 activation in response to either leptin or a soluble interleukin IL-6 receptor-alpha/IL-6 (sIL-6R alpha/IL-6) trans-signalling complex but not protein kinase C activator phorbol 12-myristate 13-acetate. The inhibitory effects of cAMP on sIL-6R alpha/IL-6-stimulated phosphorylation of ERK1,2 and STAT3 were abolished by either short interfering (si) RNA-mediated knockdown or genetic ablation of suppressor of cytokine signalling-3 (SOCS-3). The inhibitory effect of cAMP could not be reversed by inhibition of cAMP-dependent protein kinase (PKA) but was blocked by depletion of the alternative intracellular cAMP sensor exchange protein activated by cAMP 1 (Epac1), which is also required to observe SOCS-3 accumulation in response to cAMP. Interestingly, the ability of cAMP elevation to inhibit IL-6 signalling was blocked by ERK inhibition. Consistent with this observation, cAMP elevation in HUVECs produced a transient yet robust activation of ERK, and subsequent phosphorylation of transcription factor C/EBP beta, both of which were resistant to PKA inhibition. However, siRNA depletion and immunoblotting experiments revealed that neither Epac1 nor Epac2 contributed to the PKA-independent activation of ERK1,2 observed following cAMP elevation. Together, these observations suggest that while SOCS-3 induction and subsequent inhibition of cytokine-mediated phosphorylation of ERK1,2 and STAT3 in response to cAMP require Epac1 and a transient PKA-independent activation of the ERK pathway, these two events are controlled by distinct mechanisms. In addition, it reveals a novel Epac-dependent mechanism by which cAMP can specifically inhibit ERK in response to cytokine receptor activation.

Role of MCP-1 in cardiovascular disease: molecular mechanisms and clinical implications

Many of the major diseases, including cardiovascular disease, are widely recognized as inflammatory diseases. MCP-1 (monocyte chemotactic protein-1) plays a critical role in the development of cardiovascular diseases. MCP-1, by its chemotactic activity, causes diapedesis of monocytes from the lumen to the subendothelial space where they become foam cells, initiating fatty streak formation that leads to atherosclerotic plaque formation. Inflammatory macrophages probably play a role in plaque rupture and the resulting ischaemic episode as well as restenosis after angioplasty. There is strong evidence that MCP-1 plays a major role in myocarditis, ischaemia/reperfusion injury in the heart and in transplant rejection. MCP-1 also plays a role in cardiac repair and manifests protective effects under certain conditions. Such protective effects may be due to the induction of protective ER (endoplasmic reticulum) stress chaperones by MCP-1. Under sustained ER stress caused by chronic exposure to MCP-1, the protection would break down resulting in the development of heart failure. MCP-1 is also involved in ischaemic angiogenesis. The recent advances in our understanding of the molecular mechanisms that might be involved in the roles that MCP-1 plays in cardiovascular disease are reviewed. The gene expression changes induced by the signalling events triggered by MCP-1 binding to its receptor include the induction of a novel zinc-finger protein called MCPIP (MCP-1-induced protein), which plays critical roles in the development of the pathophysiology caused by MCP-1 production. The role of the MCP-1/CCR2 (CC chemokine receptor 2) system in diabetes, which is a major risk factor for cardiovascular diseases, is also reviewed briefly. MCP-1/CCR2- and/or MCPIP-targeted therapeutic approaches to intervene in inflammatory diseases, including cardiovascular diseases, may be feasible.

Sulodexide suppresses inflammation in human endothelial cells and prevents glucose cytotoxicity

Sulodexide is a mixture of heparin and dermatan sulfate with antithrombotic and profibrynolytic activity. Individual reports suggest the anti-inflammatory action of sulodexin. The goal of this study was to evaluate the effect of sulodexide on the release of the inflammatory mediators from endothelium in normal conditions and in cells chronically exposed to glucose. The experiments were performed on in vitro cultured human umbilical endothelial cells kept for 7 days in standard medium or in the same medium but supplemented with glucose 30 mmol/L. Sulodexide was added to the culture medium in concentrations of 0.125 lipase releasing unit (LRU)/mL, 0.25 LRU/mL, and 0.5 LRU/mL Spontaneous generation of oxygen-derived free radicals and the release of monocyte chemotactic protein-1 (MCP-1) and interleukin-6 (IL-6) from the studied cells was evaluated. Additionally, the healing of the injured mesothelium was studied in the presence of sulodexide and glucose. Sulodexide caused the inhibition of the intracellular generation of free radicals in a dose-dependent manner (maximally by 32%, P < 0.01), as well as the inhibition of MCP-1 (maximally by 60%, P < 0.001) and IL-6 (maximally by 69%, P < 0.01). Cells cultured in a medium with glucose 30 mmol/L generated more free radicals (+20%, P < 0.05) and released more MCP-1 (+113%, P < 0.001) and IL-6 (+26%, P < 0.05). Cell monolayers treated with glucose had a decreased ability to heal after mechanical injury (-28%, P < 0.001). All these glucose effects were reversed when cells were exposed to sulodexide simultaneously. The results of our study demonstrate a significant anti-inflammatory action of sulodexide in the endothelial cells and a protective effect of that drug against glucose cytotoxicity.

HIV-associated lipodystrophy: a review of underlying mechanisms and therapeutic options

Lipodystrophy (LD) is a common adverse effect of HIV treatment with highly active antiretroviral therapy, which comprises morphological and metabolic changes. The underlying mechanisms for LD are thought to be due to mitochondrial toxicity and insulin resistance, which results from derangements in levels of adipose tissue-derived proteins (adipocytokines) that are actively involved in energy homeostasis. Several management strategies for combating this syndrome are available, but they all have limitations. They include: switching from thymidine analogues to tenofovir or abacavir in lipoatrophy, or switching from protease inhibitors associated with hyperlipidaemia to a protease-sparing option; injection into the face with either biodegradable fillers such as poly-L-lactic acid and hyaluronic acid (a temporary measure requiring re-treatment) or permanent fillers such as bio-alcamid (with the risk of foreign body reaction or granuloma formation); and structured treatment interruption with the risk of loss of virological control and disease progression. There is therefore a need to explore alternative therapeutic options. Some new approaches including adipocytokines, uridine supplementation, glitazones, growth hormone (or growth hormone-releasing hormone analogues), metformin and statins (used alone or in combination) merit further investigation.

Cell vehicle targeting strategies

Use of cells as therapeutic carriers has increased in the past few years and has developed as a distinct concept and delivery method. Cell-based vehicles are particularly attractive for delivery of biotherapeutic agents that are difficult to synthesize, have reduced half-lives, limited tissue penetrance or are rapidly inactivated upon direct in vivo introduction. Initial studies using cell-based approaches served to identify some of the key factors for the success of this type of therapeutic delivery. These factors include the efficiency of cell loading with a therapeutic payload, the means of cell loading and the nature of therapeutics that cells can carry. However, one important aspect of cell-based delivery yet to be fully investigated is the process of actual delivery of the cell payload in vivo. In this regard, the potential ability of cell carriers to provide site-specific or targeted delivery of therapeutics deserves special attention. The present review focuses on a variety of targeting approaches that may be utilized to improve cell-based therapeutic delivery strategies. The different aspects of targeting that can be applied to cell vehicles will be discussed, including physical methods for directing cell distribution, intrinsic cell-mediated homing mechanisms and the feasibility of engineering cells with novel targeting mechanisms. Development of cell targeting strategies will further advance cell vehicle applications, broaden the applicability of this delivery approach and potentiate therapeutic outcomes.

Level of Toll-like receptor agonist exposure differentially determines chemokine production in humans

Toll-like receptor (TLR) agonists, ubiquitously present in the environment, are key players in activating synthesis of cytokines and chemokines that control normal and pathophysiological processes, including multiple inflammatory diseases. TLR2 and TLR4 respond to bacterial cell wall products. We examined the impact of TLR activation on human immune capacity using stimuli ranging from the low levels seen in most environments to the high concentrations widely used for in vitro studies. Peripheral blood mononuclear cells from 117 healthy children were activated with lipopolysaccharide (TLR4 ligand) or peptidoglycan (TLR2 ligand) over a million-fold range of concentrations. Resulting interleukin-6, CCL2, and CCL22 production were quantified by ELISA. The intensity of cytokine production elicited was linearly related to the intensity of the stimulus up to maximal responses. In marked contrast, chemokine production was not linearly related to agonist concentration. Responses rose with increasing stimulation, and then were markedly reduced (40%-100%, p < 0.0001) in response to the high levels of TLR stimulation most commonly cited. Thus, the levels of TLR4 and TLR2 agonists typically used for in vitro interrogation of immune capacity yield results clearly distinct from those obtained using commonly occurring environmental levels of TLR ligands. These findings demonstrate the importance of utilizing TLR ligands at concentrations more closely mimicking environmental levels when assessing immune capacity.

Gingival levels of monocyte chemoattractant protein-1 (MCP-1) in diabetes mellitus and periodontitis: an experimental study in rats

The objectives of this study were to investigate and compare the monocyte chemoattractant protein-1 (MCP-1) levels of gingival tissues in diabetes mellitus (DM) and periodontitis and to reveal the effects of MCP-1 on periodontal inflammation and destruction in these diseases. DM was created in 15 rats (group 1) by streptozotocin injection, and periodontitis was obtained by ligature induction in 15 rats (group 2). Fifteen systemically and periodontally healthy rats were used as control (group 3). Gingival MCP-1 levels were measured by enzyme-linked immunosorbent assay (ELISA). Periodontal inflammation was quantified by the inflammatory cell infiltration in the gingival samples, whereas periodontal destruction was assessed by the alveolar bone loss in the experimental regions. MCP-1 concentrations were higher in groups 1 and 2 than in group 3 (p < 0.001). Increased gingival inflammatory cell infiltration and alveolar bone loss were observed in groups 1 and 2 compared to group 3 (p < 0.001). There were positive correlations among the MCP-1 level, gingival inflammatory cell infiltration, and alveolar bone loss in groups 1 and 2 (p < 0.001). Our results suggest that (1) DM may lead to enhanced MCP-1 production in periodontal tissues likewise for periodontitis and (2) there may be a positive correlation between the MCP-1 concentration and diseased nature of periodontium in both diseases.