Familial hypercholesterolemia (FH) is associated with low-grade systemic inflammation, a key driver of premature atherosclerosis. We investigated the effects of inhibiting proprotein convertase ...subtilisin/kexin type 9 (PCSK9) function on inflammatory state, endothelial dysfunction and cardiovascular outcomes in patients with FH. Fourteen patients with FH were evaluated before and 8 weeks after administration of a PCSK9 blocking monoclonal antibody (alirocumab, 150 mg/subcutaneous/14 days). In vivo and ex vivo analysis revealed that alirocumab blunted the attachment of leukocytes to TNFα-stimulated human umbilical arterial endothelial cells (HUAEC) and suppressed the activation of platelets and most leukocyte subsets, which was accompanied by the diminished expression of CX3CR1, CXCR6 and CCR2 on several leukocyte subpopulations. By contrast, T-regulatory cell activation was enhanced by alirocumab treatment, which also elevated anti-inflammatory IL-10 plasma levels and lowered circulating pro-inflammatory cytokines. Plasma levels of IFNγ positively correlated with levels of total and LDL-cholesterol, whereas circulating IL-10 levels negatively correlated with these key lipid parameters. In vitro analysis revealed that TNFα stimulation of HUAEC increased the expression of PCSK9, whereas endothelial PCSK9 silencing reduced TNFα-induced mononuclear cell adhesion mediated by Nox5 up-regulation and p38-MAPK/NFκB activation, concomitant with reduced SREBP2 expression. PCSK9 silencing also decreased endothelial CX3CL1 and CXCL16 expression and chemokine generation. In conclusion, PCSK9 inhibition impairs systemic inflammation and endothelial dysfunction by constraining leukocyte-endothelium interactions. PCSK9 blockade may constitute a new therapeutic approach to control the inflammatory state associated with FH, preventing further cardiovascular events in this cardiometabolic disorder.
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•Endothelial dysfunction and systemic inflammation are key atherogenesis drivers.•PCSK9 has a functional role in systemic inflammation and endothelial dysfunction.•Alirocumab treatment dampens the low-grade inflammatory state associated with FH.•Endothelial PCSK9 inhibition attenuates endothelial dysfunction in vitro.•PCSK9 blockade is a promising strategy to prevent cardiovascular events in FH.
Extremely variable prevalence rates of atherogenic dyslipidaemia (AD) in type 2 diabetes (T2DM) subjects have been reported. The primary aim was to assess AD prevalence in Spanish T2DM subjects. ...Secondary objectives were to evaluate the differential clinical characteristics between T2DM subjects with and without AD, to describe lipid profile evolution and use of lipid‐lowering treatment in clinical practice by the Spanish Lipid Units. Data was obtained from the National Registry of Dyslipidaemias of the Spanish Atherosclerosis Society, from a multicentric sub‐study focused on AD prevalence in T2DM subjects (PREDISAT study). The inclusion criteria were subjects diagnosed of T2DM with age ≥18 years old. A total of 385 T2DM subjects with a mean age of 61 years and 246 (64%) men were included. The mean follow‐up was 22 ± 7.4 months. At baseline, 41.3% of the T2DM subjects presented AD, this percentage decreasing to 34.8% with therapeutic intervention. AD prevalence varied in different age groups and appeared to be more prevalent in younger T2DM subjects. Those with AD had a more atherogenic lipid profile at baseline, with higher total cholesterol, triglyceride and non‐(high‐density lipoprotein) HDL cholesterol levels at baseline, together with lower HDL cholesterol concentrations, without achieving lipid subfraction goals during follow‐up. Although almost 90% of the AD subjects were under lipid‐lowering treatment, most were receiving only one drug, being statins the most used treatmentA high AD prevalence in T2DM subjects was observed, being age a determinant factor, with a modest decline during follow‐up. Although almost 90% of the AD subjects were under lipid‐lowering drugs, most were only receiving monotherapy with statins.
Patients with heterozygous familial hypercholesterolemia (HeFH) have been reported to be less vulnerable to type 2 diabetes mellitus (T2DM), although the mechanism is unknown. The aims of the present ...study were to assess the effects of low density lipoprotein (LDL) cholesterol concentration and the presence of FH-causing mutations on T2DM prevalence in HeFH. Data were collected from the Dyslipidemia Registry of the Spanish Arteriosclerosis Society. Inclusion criteria were definite or probable HeFH in patients aged ≥18 years. T2DM prevalence in HeFH patients was compared with data of the general population. 1732 patients were included. The prevalence of T2DM was lower in patients with HeFH compared with the general population (5.94% vs 9.44%; OR: 0.606, 95% CI 0.486-0.755, p < 0.001). Risk factors for developing T2DM were male sex, age, body mass index, hypertension, baseline triglyceride levels and years on statin therapy. The prevalence of T2DM in HeFH patients was 40% lower than that observed in the general population. Gene mutations and LDL cholesterol concentrations were not risk factors associated with the prevalence of T2DM in patients with HeFH. The prevalence of T2DM in patients with HeFH was 40% lower than in the general population matched for age and sex.
Aims/hypothesis
Recent clinical studies indicate that glucagon-like peptide-1 (GLP-1) analogues prevent acute cardiovascular events in type 2 diabetes mellitus but their mechanisms remain unknown. In ...the present study, the impact of GLP-1 analogues and their potential underlying molecular mechanisms in insulin resistance and atherosclerosis are investigated.
Methods
Atherosclerosis development was evaluated in
Apoe
−/−
Irs2
+/−
mice, a mouse model of insulin resistance, the metabolic syndrome and atherosclerosis, treated with the GLP-1 analogues lixisenatide or liraglutide. In addition, studies in
Apoe
−/−
Irs2
+/−
mice and mouse-derived macrophages treated with lixisenatide were performed to investigate the potential inflammatory intracellular pathways.
Results
Treatment of
Apoe
−/−
Irs2
+/−
mice with either lixisenatide or liraglutide improved glucose metabolism and blood pressure but this was independent of body weight loss. Both drugs significantly decreased atheroma plaque size. Compared with vehicle-treated control mice, lixisenatide treatment generated more stable atheromas, with fewer inflammatory infiltrates, reduced necrotic cores and thicker fibrous caps. Lixisenatide-treated mice also displayed diminished IL-6 levels, proinflammatory Ly6C
high
monocytes and activated T cells. In vitro analysis showed that, in macrophages from
Apoe
−/−
Irs2
+/−
mice, lixisenatide reduced the secretion of the proinflammatory cytokine IL-6 accompanied by enhanced activation of signal transducer and activator of transcription (STAT) 3, which is a determinant for M2 macrophage differentiation. STAT1 activation, which is essential for M1 phenotype, was also diminished. Furthermore, atheromas from lixisenatide-treated mice showed higher arginase I content and decreased expression of inducible nitric oxide synthase, indicating the prevalence of the M2 phenotype within plaques.
Conclusions/interpretation
Lixisenatide decreases atheroma plaque size and instability in
Apoe
−/−
Irs2
+/−
mice by reprogramming macrophages towards an M2 phenotype, which leads to reduced inflammation. This study identifies a critical role for this drug in macrophage polarisation inside plaques and provides experimental evidence supporting a novel mechanism of action for GLP-1 analogues in the reduction of cardiovascular risk associated with insulin resistance.
Diagnosing Insulin Resistance by Simple Quantitative Methods in Subjects With Normal Glucose Metabolism
Juan F. Ascaso , MD ,
Susana Pardo , MD ,
José T. Real , MD ,
Rosario I. Lorente , MD ,
Antonia ...Priego , MD and
Rafael Carmena , MD
From the Endocrinology Service, Hospital Clínico Universitario, University of Valencia, Spain
Address correspondence and reprint requests to Juan F. Ascaso, MD, Department of Medicine, University of Valencia, Blasco
Ibáñez 15, E-46010 Valencia, Spain. E-mail: ascaso{at}uv.es
Abstract
OBJECTIVE —To identify a reliable yet simple indirect method for detection of insulin resistance (IR).
RESEARCH DESIGN AND METHODS —A total of 65 subjects (44 men and 21 women aged 30–60 years) were selected by a simple random sampling method. Inclusion
criteria were voluntary participation from staff and hospital personnel, absence of abnormal glucose tolerance, and normal
results of lipid profile and basic blood chemistry. A blood sample was taken after a 12-h overnight fast to determine plasma
lipid, glucose, and insulin levels. An intravenous glucose tolerance test with administration of insulin after 20 min and
extraction of multiple blood samples for glucose and insulin measurements and calculation of the minimal model approximation
of the metabolism of glucose (MMAMG) S i value were performed. Three indirect indexes used to predict insulin sensitivity or IR were calculated, and metabolic syndrome
was diagnosed using the Adult Treatment Panel III (ATP III) criteria. All results were correlated with those of the MMAMG.
RESULTS —The 75th percentile value as the cutoff point to define IR corresponded with a fasting plasma glucose level of 12 mU/l, a
homeostasis model assessment of 2.6, a 25th percentile for S i value of 21, and QUICKI (quantitative insulin sensitivity check index) and McAuley indexes of 0.33 and 5.8, respectively.
The S i index correlated ( P < 0.001) with all the indirect indexes and parameters of the metabolic syndrome.
CONCLUSIONS —When compared with the S i index, the most sensitive and specific indirect method was the score proposed by McAuley et al. (specificity 0.91, sensitivity
0.75, 9.2 probability ratio of a positive test), followed by the existence of metabolic syndrome (specificity 0.91, sensitivity
0.66, 7.8 probability ratio of a positive test).
ATP III, Adult Treatment Panel III
HOMA, homeostasis model assessment
IR, insulin resistance
MMAMG, minimal model approximation of the metabolism of glucose
QUICKI, quantitative insulin sensitivity check index
Footnotes
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
Accepted August 18, 2003.
Received February 10, 2003.
DIABETES CARE
Abstract
Aims
Angiotensin-II (Ang-II) is the main effector peptide of the renin-angiotensin system (RAS) and promotes leucocyte adhesion to the stimulated endothelium. Because RAS activation and ...Ang-II signalling are implicated in metabolic syndrome (MS) and abdominal aortic aneurysm (AAA), we investigated the effect of Ang-II on CXCL16 arterial expression, the underlying mechanisms, and the functional role of the CXCL16/CXCR6 axis in these cardiometabolic disorders.
Methods and results
Results from in vitro chamber assays revealed that CXCL16 neutralization significantly inhibited mononuclear leucocyte adhesion to arterial but not to venous endothelial cells. Flow cytometry and immunofluorescence studies confirmed that Ang-II induced enhanced endothelial CXCL16 expression, which was dependent on Nox5 up-regulation and subsequent RhoA/p38-MAPK/NFκB activation. Flow cytometry analysis further showed that MS patients had higher levels of platelet activation and a higher percentage of circulating CXCR6-expressing platelets, CXCR6-expressing-platelet-bound neutrophils, monocytes, and CD8+ lymphocytes than age-matched controls, leading to enhanced CXCR6/CXCL16-dependent adhesion to the dysfunctional (Ang-II- and TNFα-stimulated) arterial endothelium. Ang-II-challenged apolipoprotein E-deficient (apoE−/−) mice had a higher incidence of AAA, macrophage, CD3+, and CXCR6+ cell infiltration and neovascularization than unchallenged animals, which was accompanied by greater CCL2, CXCL16, and VEGF mRNA expression within the lesion together with elevated levels of circulating soluble CXCL16. Significant reductions in these parameters were found in animals co-treated with the AT1 receptor antagonist losartan or in apoE−/− mice lacking functional CXCR6 receptor (CXCR6GFP/GFP).
Conclusion
CXCR6 expression on platelet-bound monocytes and CD8+ lymphocytes may constitute a new membrane-associated biomarker for adverse cardiovascular events. Moreover, pharmacological modulation of this axis may positively affect cardiovascular outcome in metabolic disorders linked to Ang-II.
Impaired angiogenesis is linked to adipose tissue (AT) dysfunction, inflammation, and insulin resistance in human obesity. Chemokine (C-X-C motif) receptor. (CXCR3) ligands are important regulators ...of angiogenesis in different disease contexts such as cancer; however, their role in human morbid obesity is unknown. We investigated the role of the CXCR3 axis in AT angiogenesis in morbidly obese patients.
The study group comprised 50 morbidly obese patients (mean age 44 ± 1 years, body mass index 44 ± 1 kg/m
) who had undergone laparoscopic Roux-Y-gastric bypass surgery, and 25 age-matched non-obese control subjects. We measured the circulating levels of the CXCR3 ligands monokine induced by interferon-γ (MIG/CXCL9), interferon-γ inducible protein 10 (IP-10/CXCL10), and interferon-γ-inducible T-cell alpha chemoattractant (I-TAC/CXCL11) in all studied subjects. Additionally, the expression of CXCR3 ligands was analyzed in paired biopsies of subcutaneous and visceral AT obtained during the laparoscopic procedure in morbidly obese patients. Additionally, we explored the functional role of CXCR3 ligands on angiogenesis in AT from morbidly obese patients using an ex vivo assay.
Plasma levels of CXCL10 and CXCL11 were significantly higher in morbidly obese patients than in controls (p < 0.01). In ex vivo assays, angiogenic growth was markedly lower in visceral AT than in subcutaneous AT (p < 0.05), which was related to significant tissue upregulation of CXCL10, CXCL11 and CXCR3 (p < 0.05). CXCL10 or CXCL11 inhibited AT angiogenesis (p < 0.05), and blockade of CXCR3 function significantly increased capillary sprouting in visceral fat deposits (p < 0.05). Western blot analysis showed that the p38 mitogen-activated protein kinase signaling pathway was implicated in the angiostatic effects of CXCR3 in AT.
CXCL10 and CXCL11 may play. deleterious role in obesity as potential inhibitors of AT angiogenesis. Accordingly, pharmacological blockade of CXCR3 could represent. therapy to prevent AT dysfunction in obesity.
Different lines of evidence suggest that oxidative stress (OS) is implicated in the pathogenesis of diabetic neuropathy. The Semmes-Weinstein monofilament (SWM) test is an efficient tool for ...evaluating diabetic polyneuropathy and diabetic foot. In this study, we analyzed the association between OS markers and altered SWM test results in type 2 diabetes (T2DM) patients.
Seventy T2DM patients were studied and 34 showed altered SWM results. The clinical and biochemical parameters were determined using standardized methods. Levels of oxidized glutathione (GSSG) and malondialdehyde (MDA) were measured in circulating mononuclear cells using high-performance liquid chromatography.
We found that T2DM patients with altered SWM test results had significantly higher GSSG (3.53 ± 0.31 vs. 3.31 ± 0.35 mmol/ml, p < 0.05) and MDA (1.88 ± 0.16 vs. 1.75 ± 0.19 nmol/ml, p < 0.01) values compared to diabetic patients with normal SWM test outcomes. Moreover, altered SWM test results were independently related to age, glycosylated hemoglobin, and GSSG levels, but there was no association between OS markers and altered neuropathy sensitivity score (NSS) values.
Alteration of the glutathione system and MDA values in T2DM patients are associated with loss of proprioceptive (pressure) sensitivity, but not with symptomatic polyneuropathy (as evaluated by NSS). This finding may be important for understanding how OS affects distal symmetric polyneuropathy in diabetic patients.
To evaluate the changes in glycemia, insulinemia, and oxidative stress markers during an oral fat load test in nondiabetic subjects with abdominal obesity and to analyze the association between ...postprandial oxidative stress markers and postprandial glucose and insulin responses.
We included 20 subjects with abdominal obesity (waist circumference > 102 cm for men and > 88 cm for women) and 20 healthy lean controls (waist circumference < 102 cm for men and < 88 cm for women). After 12 hours of fasting we performed a standardized fat load test (0-8 hours) with supracal® (50 g/m2). We determined metabolic parameters, oxidized and reduced glutathione, and malondialdehyde.
In both groups, insulin, HOMA, oxidized/reduced glutathione ratio, and malondialdehyde significantly decreased in the postprandial state after the OFLT. All these parameters were significantly higher in the abdominal obesity group at baseline and during all the postprandial points, but the reduction from the baseline levels was significantly higher in the abdominal obesity group.
Unsaturated fat improves insulin resistance and oxidative stress status. It is possible that a consumption of unsaturated fat could be beneficial even in subjects with abdominal obesity in postprandial state.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Diabetic peripheral neuropathy (DPN) is a chronic complication of diabetes mellitus associated with high morbidity and mortality. Major risk factors for DPN include metabolic changes, ...duration of diabetes, nerve ischaemia and derangements in regeneration and nerve repair programmes. Chemokines have been previously implicated in the pathogenesis of various neuropathies and neuropathic pain processes. The aim of this pilot study was to evaluate the association between the plasma levels of chemokines (CXCL9, CXCL10 and CXCL11) in the presence of DPN in a cohort of type 2 diabetes (T2D) patients.
Materials and methods
We studied 73 patients with T2D: 36 with DPN and 37 without DPN. DPN was established through the Semmes‐Weinstein test (SW). Plasma levels of circulating chemokines CXCL9, CXCL10 and CXCL11 were determined using DuoSet ELISA kits (Abingdon, UK).
Results
We found that levels of CXCL10 were significantly higher in patients with DPN than amongst patients without DPN (57.6 ± 38.3 vs 38.1 ± 33.4 pg/mL, respectively; P = .034). Serum levels of chemokine CXCL9 were also higher amongst patients with DPN but did not reach a statistical significance (188.1 ± 72.7 and 150.4 ± 83.6 pg/mL, respectively, P = .06).
Conclusions
Increased circulating levels of CXCL10 were associated with DPN in T2D patients, suggesting a role of this chemokine in the DPN. Determination of CXCL10 levels could be used as a marker for the early detection and implementation of therapeutic strategies in order to reverse and prevent the DPN.
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