ILC2 transfers to apolipoprotein E deficient mice reduce the lipid content of atherosclerotic lesions.

BACKGROUND: Expansion of type 2 innate lymphoid cells (ILC2s) in hypercholesterolaemic mice protects against atherosclerosis while different ILC2 subsets have been described (natural, inflammatory) based on their suppression of tumorigenicity 2 (ST2) and killer-cell lectin like receptor G1 (KLRG1) expression. The aim of the current study is to characterize the interleukin 25 (IL25)-induced splenic ILC2 population (Lin-CD45+IL17RB+ICOS+IL7raintermediate) and address its direct role in experimental atherosclerosis by its adoptive transfer to hypercholesterolaemic apolipoprotein E deficient (apoE-/-) mice. RESULTS: Immunomagnetically enriched, FACS-sorted ILC2s from the spleens of IL-25 treated apoE-/- mice were stained for KLRG1 and ST2 directly upon cell obtainment or in vitro cell expansion for flow cytometric analysis. IL25-induced splenic ILC2s express high levels of both KLRG1 and ST2. However, both markers are downregulated upon in vitro cell expansion. In vitro expanded splenic ILC2s were intraperitoneally transferred to apoE-/- recipients on high fat diet. ApoE-/- mice that received in vitro expanded splenic ILC2s had decreased lipid content in subvalvular heart and brachiocephalic artery (BCA) plaques accompanied by increased peritoneal B1 cells, activated eosinophils and alternatively activated macrophages (AAMs) as well as anti-phosphorylcholine (PC) immunoglobulin (Ig) M in plasma. CONCLUSIONS: With the current data we designate the IL25-induced ILC2 population to decrease the lipid content of atherosclerotic lesions in apoE-/- mice and we directly link the induction of B1 cells and the atheroprotective anti-PC IgM antibodies with ILC2s.

High Levels of Soluble Lectinlike Oxidized Low-Density Lipoprotein Receptor-1 Are Associated With Carotid Plaque Inflammation and Increased Risk of Ischemic Stroke.

Background When the lectinlike oxidized low-density lipoprotein (ox LDL) receptor-1 ( LOX -1), a scavenger receptor for ox LDL , binds ox LDL , processes leading to endothelial dysfunction and inflammation are promoted. We aimed to study release mechanisms of LOX -1 and how circulating levels of soluble LOX -1 ( sLOX -1) relate to plaque inflammation and future risk for ischemic stroke. Methods and Results Endothelial cells and leukocytes were used to study release of sLOX -1. Plasma levels of sLOX -1 were determined in 4703 participants in the Malmö Diet and Cancer cohort. Incidence of ischemic stroke was monitored. For 202 patients undergoing carotid endarterectomy, levels of sLOX -1 were analyzed in plasma and plaque homogenates and related to plaque inflammation factors. Endothelial cells released sLOX -1 when exposed to ox LDL . A total of 257 subjects experienced stroke during a mean follow-up of 16.5 years. Subjects in the highest tertile of sLOX -1 had a stroke hazard ratio of 1.75 (95% CI, 1.28-2.39) compared with those in the lowest tertile after adjusting for age and sex. The patients undergoing carotid endarterectomy had a significant association between plasma sLOX -1 and the plaque content of sLOX -1 ( r=0.209, P=0.004). Plaques with high levels of sLOX -1 had more ox LDL , proinflammatory cytokines, and matrix metalloproteinases. Conclusions Our findings demonstrate that ox LDL induces the release of sLOX -1 from endothelial cells and that circulating levels of sLOX -1 correlate with carotid plaque inflammation and risk for ischemic stroke. These observations provide clinical support to experimental studies implicating LOX -1 in atherosclerosis and its possible role as target for cardiovascular intervention.

Interleukin-25 reduces Th17 cells and inflammatory responses in human peripheral blood mononuclear cells.

BACKGROUND: The absence of interleukin-25 (IL-25) favors the induction of Th1 and Th17 immune responses in mice. Th1 immune responses have been associated with the pathology of atherosclerosis, a lipid and inflammation driven disease of the arterial wall. PURPOSE OF RESEARCH: To evaluate the effect of IL-25 on human peripheral blood mononuclear cells (hPBMCs) in the presence and absence of oxidized low density lipoprotein (oxLDL), a key player in atherosclerosis development. PRINCIPAL RESULTS: Human PBMCs were incubated with recombinant human IL-25 (rhIL-25) in the presence and absence of oxLDL and analyzed with flow cytometry while cytokine secretion was measured in cell culture supernatants. The IL-25 receptor, IL-17RB, was mostly expressed on T cells. Incubation of hPBMCs with IL-25 reduced the frequency of Th17 cells. Furthermore, IL-25 inhibited the release of the Th17-inducing cytokine IL-6 from dendritic cells isolated from hPBMCs indicating that the IL-25 mediated Th17 suppression may be indirect. Moreover, IL-25 reduced the secretion of the proinflammatory cytokine IFNγ from hPBMCs. OxLDL decreased IFNγ release from hPBMCs regardless of the presence or absence of IL-25. CONCLUSIONS: IL-25 reduces Th1 and Th17 immune responses in hPBMCs raising the interesting possibility that IL-25 could have a protective role in human atherosclerosis.

Cardiovascular disease in systemic lupus erythematosus is associated with increased levels of biomarkers reflecting receptor-activated apoptosis.

BACKGROUND AND AIMS: There is convincing evidence that adaptive immune responses affect the development of atherosclerosis and thrombosis and several autoimmune diseases are associated with increased cardiovascular risk. However, our understanding of the underlying mechanisms remains limited. We investigated how biomarkers reflecting four aspects of autoimmunity: apoptosis, inflammation, tissue degradation and repair, associate with cardiovascular disease (CVD) in subjects with systemic lupus erythematosus (SLE). METHODS: We investigated 484 well-characterized SLE patients, 69 of whom had CVD (coronary artery disease, cerebrovascular disease or peripheral artery disease), and 253 controls. Occurrence of carotid plaques was investigated with ultrasound. Plasma levels of biomarkers reflecting apoptosis (Fas, TNF receptor 1, TRAIL receptor 2), inflammation (IL-6, IL-8, monocyte chemotactic protein-1), tissue degradation (matrix metalloproteinase (MMP)-1, MMP-3, MMP-7), and tissue repair (platelet-derived growth factor, epidermal growth factor and stem cell factor) were analyzed by Proximity Extension Assay. RESULTS: Subjects with SLE had markedly elevated plasma levels of biomarkers reflecting apoptosis, inflammation and tissue degradation as compared to controls. SLE patients with CVD had higher levels of Fas, TNF receptor 1, TRAIL receptor 2, MMP-1 and -7 than those without CVD. The same associations were found for the presence of a carotid plaque. When controlling for the factors included in the Framingham risk score, all biomarkers except MMP-1 remained associated with the presence of a carotid plaque, while only TRAIL receptor 2 levels remained significantly associated with CVD. CONCLUSIONS: Our findings argue that the cardiovascular risk in SLE is associated with increased cell death by apoptosis and tissue degradation.

FADD, Caspase-3, and Caspase-8 and Incidence of Coronary Events.

OBJECTIVE: To investigate the relationship between 3 markers of apoptosis, that is, FADD (Fas-associated death domain-containing protein), caspase-3, and caspase-8, and incidence of coronary events (CEs) in a population-based cohort study. APPROACH AND RESULTS: In vitro experiments were performed to assess the response of the apoptotic biomarkers after Fas stimulation of peripheral blood mononuclear cells. The experiments showed significantly increased releases of FADD, caspase-3, and caspase-8 after Fas stimulation. The relationship between FADD, caspase-3, and caspase-8, respectively, and incidence of CEs was studied in 4284 subjects from the population-based Malmö Diet and Cancer Study. Cox' proportional hazards regression was used to examine the association between the apoptotic biomarkers and incidence of CE over a mean follow-up of 19 years. A total of 381 individuals had CE during the follow-up. High FADD at baseline was significantly associated with incident CE. In the highest compared with the lowest quartile of FADD, the risk factor adjusted hazards ratio for CE was 1.82 (95% confidence interval, 1.35-2.46; P for trend <0.001). A significant association was also found between caspase-8 and CE; the hazards ratio (Q4 versus Q1) was 1.90 (95% confidence interval, 1.39-2.60; P for trend <0.001) after adjustment for risk factors. No association was found between caspase-3 and CEs. CONCLUSIONS: High levels of FADD and caspase-8, but not caspase-3, were associated with increased incidence of CE in subjects from the general population. The in vitro experiments support the view that these biomarkers could reflect activation of the extrinsic apoptotic pathway.

oxLDL antibody inhibits MCP-1 release in monocytes/macrophages by regulating Ca2+ /K+ channel flow.

oxLDL peptide vaccine and its antibody adoptive transferring have shown a significantly preventive or therapeutic effect in atherosclerotic animal model. The molecular mechanism behind this is obscure. Here, we report that oxLDL induces MCP-1 release in monocytes/macrophages through their TLR-4 (Toll-like receptor 4) and ERK MAPK pathway and is calcium/potassium channel-dependent. Using blocking antibodies against CD36, TLR-4, SR-AI and LOX-1, only TLR-4 antibody was found to have an inhibitory effect and ERK MAPK-specific inhibitor (PD98059) was found to have a dramatic inhibitory effect compared to inhibitors of other MAPK group members (p38 and JNK MAPKs) on oxLDL-induced MCP-1 release. The release of cytokines and chemokines needs influx of extracellular calcium and imbalance of efflux of potassium. Nifedipine, a voltage-dependent calcium channel (VDCC) inhibitor, and glyburide, an ATP-regulated potassium channel (K+ATP ) inhibitor, inhibit oxLDL-induced MCP-1 release. Potassium efflux and influx counterbalance maintains the negative potential of macrophages to open calcium channels, and our results suggest that oxLDL actually induces the closing of potassium influx channel - inward rectifier channel (Kir ) and ensuing the opening of calcium channel. ERK MAPK inhibitor PD98059 inhibits oxLDL-induced Ca2+ /Kir channel alterations. The interfering of oxLDL-induced MCP-1 release by its monoclonal antibody is through its FcγRIIB (CD32). Using blocking antibodies against FcγRI (CD64), FcγRIIB (CD32) and FcγRIII (CD16), only CD32 blocking antibody was found to reverse the inhibitory effect of oxLDL antibody on oxLDL-induced MCP-1 release. Interestingly, oxLDL antibody specifically inhibits oxLDL-induced ERK MAPK activation and ensuing Ca2+ /Kir channel alterations, and MCP-1 release. Thus, we found a molecular mechanism of oxLDL antibody on inhibition of oxLDL-induced ERK MAPK pathway and consequent MCP-1 release.

Associations Between Macrophage Colony-Stimulating Factor and Monocyte Chemotactic Protein 1 in Plasma and First-Time Coronary Events: A Nested Case-Control Study.

BACKGROUND: Myeloid cells play a central role in atherosclerosis. We investigated the associations between the plasma levels of growth factors and chemokines that regulate myeloid cell homeostasis and function and the risk of first-time acute coronary events in middle-aged persons. METHODS AND RESULTS: We measured baseline plasma levels of macrophage colony-stimulating factor; monocyte chemotactic protein 1; C-C motif chemokine ligands 3, 4, and 20; C-X-C motif chemokine ligands 1, 6, and 16; and C-X3-C motif chemokine ligand 1 in 292 participants who had a coronary event during follow-up and 366 controls matched for age, sex, and time of inclusion who remained event free. Study participants were recruited from the Malmö Diet and Cancer Study population cohort and had no previous history of coronary artery disease. We found a strong independent negative association between macrophage colony-stimulating factor and incident coronary events in a forward stepwise Cox proportional hazards model including all biomarkers alongside the classic Framingham risk factors (age, sex, smoking, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure), diabetes mellitus, and medication. Conversely, monocyte chemotactic protein 1 had the strongest independent positive association with the outcome. The addition of macrophage colony-stimulating factor and monocyte chemotactic protein 1 significantly improved the predictive ability of a model including traditional risk factors alone (C statistic 0.81 [95% CI 0.78-0.84] versus 0.67 [95% CI 0.63-0.71]; net reclassification index 0.52 [0.42-0.62]; P<0.001). The combined model led to a 54% net downclassification of participants who did not have a coronary event during follow-up and was particularly effective in the intermediate-risk group. CONCLUSIONS: High levels of macrophage colony-stimulating factor and low levels of monocyte chemotactic protein 1 in plasma characterize middle-aged persons at low risk to develop clinically manifested coronary artery disease.

Endarterectomy patients with elevated levels of circulating IL-16 have fewer cardiovascular events during follow-up.

BACKGROUND AND PURPOSE: Increased interleukin 16 (IL-16) levels in carotid plaques have been associated with reduced incidence of cardiovascular (CV) events during follow-up in patients who underwent carotid endarterectomy (CEA). In the present study we aimed to determine whether high circulating levels of IL-16 also are associated with a decreased risk of CV events after CEA. METHODS: Patients, who had their carotid plaques surgically removed (n=473), were followed for a mean follow-up time of 3.1years. Plasma levels of IL-16 the day before surgery were analyzed by proximity extension assay (PEA) and associated with the occurrence of CV events during follow-up (n=98). RESULTS: High levels of circulating IL-16 were independently associated with a decreased risk of CV events when comparing the highest versus the lowest IL-16 tertile (hazard ratio [HR] 0.47; 95% CI 0.27-0.81; P=0.007), as well as with CV deaths (HR 0.25; 95% CI 0.09-0.70; P=0.008). CONCLUSION: These present findings indicate an association between IL-16 and less clinical complications of atherosclerosis in a population with known advanced carotid disease.

Apolipoprotein B-100 Antibody Interaction With Atherosclerotic Plaque Inflammation and Repair Processes.

BACKGROUND AND PURPOSE: Treatment with IgG against the malondialdehyde (MDA)-modified apolipoprotein B-100 epitope p45 reduces atherosclerosis in experimental models. This study investigated the association between p45 IgG autoantibodies and plaque inflammation in subjects with advanced cardiovascular disease. METHODS: Native and MDA-p45 IgG levels were analyzed by ELISA in 349 carotid endarterectomy patients. In a subcohort of 195 subjects, endarterectomy samples were analyzed by immunohistochemistry and ELISA to determine plaque constituents and inflammation. Peripheral blood mononuclear cells were isolated from healthy donors. RESULTS: Patients with preoperative events of neurological ischemia had lower levels of native p45 IgG. Low levels of MDA-p45 IgG were associated with increased risk of postoperative cardiovascular death during a mean follow-up of 54 months. High plasma levels of native p45 IgG were associated with increased plaque content of collagen and smooth muscle cell growth factors, as well as with lower levels of proinflammatory cytokines. Exposure of peripheral blood mononuclear cells from healthy donors to recombinant MDA-p45 IgG in presence of oxidized low-density lipoprotein reduced the expression of tumor necrosis factor-α and stimulated release of smooth muscle cell growth factors. CONCLUSIONS: This study confirms previous experimental findings of anti-inflammatory properties of apolipoprotein B-100 p45 antibodies and provides the first clinical evidence of associations between p45 IgG autoantibody levels and atherosclerotic plaque inflammation, plaque repair as well as prevalent and incident cardiovascular events in carotid endarterectomy patients. These findings suggest the possibility that treatment with anti-p45 antibodies may have beneficial effects in advanced cardiovascular disease.

Low Levels of Apolipoprotein B-100 Autoantibodies Are Associated With Increased Risk of Coronary Events.

OBJECTIVE: Previous smaller studies have indicated inverse associations between autoantibodies to oxidized low-density lipoprotein epitopes, and cardiovascular disease. The present study investigated associations between autoantibodies against the apolipoprotein B-100 peptides p45 and p210, respectively, and risk of incident cardiovascular disease in a large population-based cohort. APPROACH AND RESULTS: Apolipoprotein B-100 autoantibodies were analyzed by ELISA in a prospective study, including 5393 individuals (aged 46-68 years) belonging to the cardiovascular arm of the Malmö Diet and Cancer study with a follow-up time of >15 years. Subjects that suffered an acute coronary event during follow-up (n=382) had lower levels at baseline of IgM autoantibodies recognizing the native and malondialdehyde-modified apolipoprotein B-100 peptides p45 and p210 and also lower IgG levels recognizing native p210, whereas no association was found with risk for stroke (n=317). Subjects in the highest compared with lowest tertile of IgM-p45MDA (hazard ratio [95% confidence interval]: 0.72 [0.55, 0.94]; P=0.017) and IgG-p210native (hazard ratio [95% confidence interval]: 0.73 [0.56, 0.97]; P=0.029) had lower risk for incident coronary events after adjustment for cardiovascular risk factors in Cox proportional hazard regression models. Moreover, subjects with high levels of IgG-p210native were less likely to have carotid plaques as assessed by ultrasonography at baseline (odds ratio=0.81, 95% confidence interval 0.70-0.95, P=0.008 after adjustment for risk factors). CONCLUSIONS: This large prospective study demonstrates that subjects with high levels of apolipoprotein B-100 autoantibodies have a lower risk of coronary events supporting a protective role of these autoantibodies in cardiovascular disease.

High levels of cathepsin D and cystatin B are associated with increased risk of coronary events.

OBJECTIVE: The majority of acute coronary syndromes are caused by plaque ruptures. Proteases secreted by macrophages play an important role in plaque ruptures by degrading extracellular matrix proteins in the fibrous cap. Matrix metalloproteinases have been shown to be markers for cardiovascular disease whereas the members of the cathepsin protease family are less studied. METHODS: Cathepsin D, cathepsin L and cystatin B were measured in plasma at baseline from 384 individuals who developed coronary events (CEs), and from 409 age-matched and sex-matched controls from the Malmö Diet and Cancer cardiovascular cohort. RESULTS: Cathepsin D (180 (142-238) vs 163 (128-210), p<0.001), cathepsin L (55 (44-73) vs 52 (43-67), p<0.05) and cystatin B levels (45 (36-57) vs 42 (33-52), p<0.001) were significantly increased in CE cases compared to controls. In addition, increased cathepsin D (220 (165-313) vs 167 (133-211), p<0.001), cathepsin L (61 (46-80) vs 53 (43-68), p<0.05) and cystatin B (46 (38-58) vs 43 (34-54), p<0.05) were associated with prevalent diabetes. Furthermore, cathepsin D and cystatin B were increased in smokers. The HRs for incident CE comparing the highest to the lowest tertile(s) of cathepsin D and cystatin B were 1.34 (95% CI 1.02 to 1.75) and 1.26 (95% CI 1.01 to 1.57), respectively, after adjusting for age, sex, low-density lipoprotein/high-density lipoprotein ratio, triglycerides, body mass index, hypertension and glucose, but these associations did not remain significant after further addition of smoking to the model. In addition, cathepsin D was increased in incident CE cases among smokers after adjusting for cardiovascular risk factors. CONCLUSIONS: The associations of cathepsin D and cystatin B with future CE provide clinical support for a role of these factors in cardiovascular disease, which for cathepsin D may be of particular importance for smokers.

Human Carotid Plaques With High Levels of Interleukin-16 Are Associated With Reduced Risk for Cardiovascular Events.

BACKGROUND AND PURPOSE: Interleukin-16 (IL-16) functions as a regulator of T-cell growth and acts as an inducer of cell migration. The aim of this study was to determine whether IL-16 measured in human carotid plaques was associated with symptoms (eg, stroke, transient ischemic attack, or amaurosis fugax), markers of plaque stability, and postoperative cardiovascular events. METHODS: Plaques obtained from patients who had ≥1 cerebrovascular ischemic events within 1 month before endarterectomy (n=111) were compared with plaques from patients without symptoms (n=95). Neutral lipids, smooth muscle cell, and macrophage contents were evaluated histologically, and collagen, elastin, and caspase-3 activity were measured biochemically. IL-16, matrix metalloproteinases, and tissue inhibitors of metalloproteinases were measured in plaque homogenates using a multiplex immunoassay. IL-16, CD3, CD4, and FoxP3 mRNA expressions in carotid plaques were analyzed with quantitative real-time polymerase chain reaction. RESULTS: Carotid plaques from asymptomatic patients had higher levels of IL-16 mRNA. High plaque IL-16 protein levels (above median) were associated with reduced incidence of postoperative cardiovascular events during a mean follow-up of 21 months (hazard ratio, 0.47; 95% confidence interval, 0.22-0.99; P=0.047). IL-16 levels correlated with the plaque-stabilizing components: elastin, collagen, matrix metalloproteinase-2, tissue inhibitors of metalloproteinase-1, tissue inhibitors of metalloproteinase-2 and FoxP3 mRNA. CONCLUSIONS: This study shows that high levels of IL-16 are associated with asymptomatic carotid plaques, expression of factors contributing to plaque stability, and decreased risk of new cardiovascular events during a 2-year period after surgery, suggesting that IL-16 might have a protective role in human atherosclerotic disease.

Low Levels of IgM Antibodies against an Advanced Glycation Endproduct-Modified Apolipoprotein B100 Peptide Predict Cardiovascular Events in Nondiabetic Subjects.

Increased glucose levels are associated with the generation of advanced glycation endproduct (AGE) modifications. Interaction between AGE-modified plaque components and immune cells is believed to have an important role in the development of vascular complications in diabetes. Methylglyoxal (MGO) is one type of reactive aldehyde that gives rise to AGE modification. The present study analyzed whether autoantibodies against MGO-modified epitopes of the low-density lipoprotein apolipoprotein B (apoB) 100 predict cardiovascular events. A library consisting of 302 peptides comprising the complete apoB100 molecule was screened to identify peptides targeted by MGO-specific autoantibodies. Peptide (p) 220 (apoB amino acids 3286-3305) was identified as a major target. Baseline IgM and IgG against MGO-peptide 220 (p220) were measured in 700 individuals from the Malmö Diet and Cancer Cohort. A total of 139 cardiovascular events were registered during the 15-y follow-up period. Controlling for major cardiovascular risk factors demonstrated that subjects in the lowest tertile of MGO-p220 IgM had an increased risk for cardiovascular events (hazard ratio [95% confidence interval]: 2.07 [1.22-3.50]; p(trend) = 0.004). Interestingly, the association between MGO-p220 IgM and cardiovascular events remained and even tended to become stronger when subjects with prevalent diabetes were excluded from the analysis (2.51 [1.37-4.61]; p(trend) = 0.002). MGO-p220 IgM was inversely associated with blood glucose, but not with oxidized low-density lipoprotein. Finally, we demonstrate that anti-MGO-p220 IgM is produced by B1 cells. These data show that subjects with low levels of IgM recognizing MGO-modified p220 in apoB have an increased risk to develop cardiovascular events and that this association is present in nondiabetic subjects.

Elevated Plasma Levels of MMP-12 Are Associated With Atherosclerotic Burden and Symptomatic Cardiovascular Disease in Subjects With Type 2 Diabetes.

OBJECTIVE: Matrix metalloproteinases (MMPs) degrade extracellular matrix proteins and play important roles in development and tissue repair. They have also been shown to have both protective and pathogenic effects in atherosclerosis, and experimental studies have suggested that MMP-12 contributes to plaque growth and destabilization. The objective of this study was to investigate the associations between circulating MMPs, atherosclerosis burden, and incidence of cardiovascular disease with a particular focus on type 2 diabetes mellitus. APPROACH AND RESULTS: Plasma levels of MMP-1, -3, -7, -10, and -12 were analyzed by the Proximity Extension Assay technology in 1500 subjects participating in the SUMMIT (surrogate markers for micro- and macrovascular hard end points for innovative diabetes tools) study, 384 incident coronary cases, and 409 matched controls in the Malmö Diet and Cancer study and in 205 carotid endarterectomy patients. Plasma MMP-7 and -12 were higher in subjects with type 2 diabetes mellitus, increased with age and impaired renal function, and was independently associated with prevalent cardiovascular disease, atherosclerotic burden (as assessed by carotid intima-media thickness and ankle-brachial pressure index), arterial stiffness, and plaque inflammation. Baseline MMP-7 and -12 levels were increased in Malmö Diet and Cancer subjects who had a coronary event during follow-up. CONCLUSIONS: The plasma level of MMP-7 and -12 are elevated in type 2 diabetes mellitus, associated with more severe atherosclerosis and an increased incidence of coronary events. These observations provide clinical support to previous experimental studies, demonstrating a role for these MMPs in plaque development, and suggest that they are potential biomarkers of atherosclerosis burden and cardiovascular disease risk.

High plasma levels of heparin-binding epidermal growth factor are associated with a more stable plaque phenotype and reduced incidence of coronary events.

OBJECTIVE: Rupture of atherosclerotic plaques is the major cause of acute coronary events (CEs). Plaque destabilization is the consequence of an imbalance between inflammatory-driven degradation of fibrous tissue and smooth muscle cell-dependent tissue repair. Proinflammatory factors have been documented extensively as biomarkers of cardiovascular risk but factors that contribute to stabilization of atherosclerotic plaques have received less attention. The present study aimed to investigate whether plasma levels of the smooth muscle cell growth factor epidermal growth factor (EGF), heparin-binding-EGF (HB-EGF), and platelet-derived growth factor correlate with plaque phenotype and incidence of CEs. APPROACH AND RESULTS: HB-EGF, EGF and platelet-derived growth factor were measured in plasma from 202 patients undergoing carotid endarterectomy and in 384 incident CE cases and 409 matched controls recruited from the Malmö Diet and Cancer cohort. Significant positive associations were found between the plasma levels of all 3 growth factors and the collagen and elastin contents of the removed plaques. CE cases in the Malmö Diet and Cancer cohort had lower levels of HB-EGF in plasma, whereas no significant differences were found for EGF and platelet-derived growth factor. After adjusting for cardiovascular risk factors in a Cox proportional hazard model, the hazard ratio for the highest HB-EGF tertile was 0.61 (95% confidence interval, 0.47-0.82; P<0.001). CONCLUSIONS: The associations between high levels of smooth muscle cell growth factors in plasma and a more fibrous plaque phenotype as well as the association between low levels of HB-EGF and incident CEs point to a potential clinically important role for factors that contribute to plaque stabilization by stimulating smooth muscle cells.

A high quality diet is associated with reduced systemic inflammation in middle-aged individuals.

OBJECTIVE: To examine if overall diet quality is associated with cellular and soluble biomarkers of systemic inflammation in middle-aged individuals. METHODS: A group of 667 individuals, aged 63-68 years, selected from the cardiovascular arm of the Malmö Diet and Cancer cohort, participated in this study. Baseline examinations consisted of an extensive socio-demographic questionnaire, anthropometric measurements, blood sampling and detailed dietary data. Mononuclear leukocytes frozen at baseline were thawed and analysed with flow cytometry to quantify monocyte subsets based on CD14 and CD16 expression. Plasma cytokines were measured using multiplexed immune assays. A diet quality index consisting of six components (saturated fatty acids, polyunsaturated fatty acids, fish and shellfish, dietary fibre, fruit and vegetables, and sucrose) was constructed to measure adherence to the Swedish Nutrition Recommendations/Dietary Guidelines. General linear models were used to investigate associations between index scores and several biomarkers of inflammation. RESULTS: A higher percentage of women reported adherence to the nutritional recommendations and had better overall diet quality than men. Participants with higher diet quality were more likely to have a healthier lifestyle. The levels of high-sensitive CRP, S100A8/A9, TNF-α, white blood cells, neutrophils, lymphocytes and CD14(+)CD16(++) were lower in participants with higher index scores. The associations remained significant after adjustment for potential confounders. CONCLUSION: In this cross-sectional study, we found that a high diet quality is associated with lower systemic inflammation. As the incidence of cardiovascular disease and cancer is directly correlated with the levels of inflammation, our findings might indicate a protective role of high-quality diet.

Circulating CD40+ and CD86+ B cell subsets demonstrate opposing associations with risk of stroke.

OBJECTIVE: Accumulating evidence shows that immune cells play an important role in atherosclerosis. Most attention has focused on the role of different T cell subsets, whereas the possible involvement of B cells has been less studied. In this study, we assessed the association of 2 different B cell subsets, CD19(+)CD40(+) and CD19(+)CD86(+) B cells, with risk for development of acute cardiovascular events. APPROACH AND RESULTS: The prospective study included 700 subjects randomly selected from the cardiovascular cohort of the Malmö Diet and Cancer study. Mononuclear leukocytes, stored at -140(○)C at the baseline investigation in 1991-1994, were thawed and B cell subsets analyzed by flow cytometry. Cytokine release from CD3/CD28-stimulated mononuclear leukocytes was measured with multiplex ELISA. Baseline carotid intima-media thickness and stenosis were assessed by ultrasonography, and clinical events were monitored through validated national registers during a median/mean follow-up time of 15 years. The subjects in the highest tertile of CD19(+)CD40(+) B cells had a significantly lower risk of incident stroke after adjustment for other risk factors. In contrast, CD19(+)CD86(+) B cells were associated with higher risk for development of a stroke event and increased release of proinflammatory cytokines from mononuclear leukocytes. CONCLUSIONS: These observations provide evidence for an involvement of B cells in the incidence of stroke and suggest that both pathogenic and protective B cell subsets exist.

Antibodies against gonadotropin-releasing hormone (GnRH) in patients with diabetes mellitus is associated with lower body weight and autonomic neuropathy.

BACKGROUND: Esophageal dysmotility and gastroparesis are common secondary complications in patients with diabetes mellitus. Patients with dysmotility express antibodies against gonadotropin-releasing hormone (GnRH) in serum. The aim of the present study was to scrutinize patients with diabetes mellitus with regard to the presence of GnRH antibodies, and to examine associations between antibodies and clinical findings. RESULTS: Thirty-nine consecutive patients with diabetes mellitus were included in the study after clinical examination and examination by esophageal manometry and gastric emptying scintigraphy. Serum was analyzed for the presence of antibodies against GnRH using an ELISA, and values are expressed as relative units (RU). Two age- and gender-matched healthy subjects per each patient served as controls. The prevalence of IgM GnRH antibodies in patients was 33% compared to 14% in controls (p = 0.027), with a higher antibody titer; 1.2 (0.6-5.0) and 0.2 (0.1-0.3) RU, respectively (p = 0.000). The expression of IgG antibodies was 15% in patients and none in controls (p = 0.000). Lower body mass index was associated with the presence of IgM antibodies (OR = 0.835, 95% CI = 0.699-0.998), and autonomic neuropathy with the presence IgG antibodies (OR = 9.000, 95% CI = 1.327-61.025). Esophageal dysmotility (69%) or gastroparesis (18%) were not associated with the presence of IgM antibodies (OR = 0.589, 95% CI = 0.143-2.424 and OR = 3.407, 95% CI = 0.633-18.350, respectively). Neither was esophageal dysmotility associated with IgG antibodies (OR = 2.500, 95% CI = 0.259-24.096). CONCLUSIONS: Antibodies against GnRH are more common in patients with diabetes mellitus compared with healthy controls. IgM antibodies are associated with lower body mass index and IgG antibodies are associated with autonomic neuropathy.

Gonadotropin-releasing hormone analog buserelin causes neuronal loss in rat gastrointestinal tract.

Gonadotropin-releasing hormone (GnRH) analogs are given to women undergoing in vitro fertilization. Case reports describing the development of chronic intestinal pseudo-obstruction and auto-antibodies against GnRH after such treatment suggest a strong association between intestinal dysfunction and GnRH analogs. No experimental model for studying such a relationship is currently at hand. Our main goal was to investigate possible enteric neurodegeneration and titers of GnRH antibodies in response to repeated administration of the GnRH analog buserelin in rat. Rats were treated for 1-4 sessions with daily subcutaneous injections of buserelin or saline for 5 days, followed by 3 weeks of recovery. Buserelin treatment caused significant loss of submucous and myenteric neurons in the fundus, ileum, and colon. The loss of enteric neurons can, at least partly, be explained by increased apoptosis. No GnRH- or GnRH-receptor-immunoreactive (IR) enteric neurons but numerous luteinizing hormone (LH)-receptor-IR neurons were detected. After buserelin treatment, the relative number of enteric LH-receptor-IR neurons decreased, whereas that of nitric-oxide-synthase-IR neurons increased. No intestinal inflammation or increased levels of circulating interleukins/cytokines were noted in response to buserelin treatment. Serum GnRH antibody titers were undetectable or extremely low in all rats. Thus, repeated administrations of buserelin induce neurodegeneration in rat gastrointestinal tract, possibly by way of LH-receptor hyperactivation. The present findings suggest that enteric neurodegenerative effects of GnRH analog treatment in man can be mimicked in rat. However, in contrast to man, no production of GnRH auto-antibodies has been noted in rat.