Increased CD40 ligand and platelet-monocyte aggregates in patients with type 1 diabetes mellitus

BACKGROUND: Diabetes mellitus is a major risk factor for cardiovascular disease and is associated with a proinflammatory and prothrombotic state. We investigated whether CD40 ligand (L) expression and platelet-monocyte aggregation are increased in patients with type 1 diabetes. METHODS: Serum C-reactive protein (CRP) and soluble (s) CD40L concentrations, platelet surface CD40L expression and platelet-monocyte aggregates were measured in 22 patients with uncomplicated type 1 diabetes and 22 age- and sex-matched non-diabetic control subjects. RESULTS: In comparison to controls, patients with type 1 diabetes had higher serum CRP concentrations (3.29 +/- 0.9 mg/L versus 0.99 +/- 0.2mg/L, P = 0.01), serum sCD40L concentrations (10.0 +/- 1.4 ng/mL versus 4.6 +/- 0.6 ng/mL, P = 0.006), and platelet surface expression of CD40L (13.8 +/- 0.9% versus 8.5 +/- 1.1%, P < 0.001). Platelet-monocyte aggregates were also significantly elevated in type 1 diabetes (35.9 +/- 3.3% versus 26.4 +/- 2.9%, P = 0.005; n = 10). We also observed a significant correlation between plasma glucose and serum CRP (r = 0.53, P = 0.01) as well as platelet-monocyte aggregates (r = 0.69, P = 0.03). CONCLUSIONS: Type 1 diabetes is associated with increased CD40L expression and platelet-monocyte aggregation, which may contribute to the proinflammatory and prothrombotic state as well as the accelerated atherogenesis associated with this disorder.     

Early increase of oxidative stress and soluble CD40L in children with hypercholesterolemia.

OBJECTIVES: The aim of the study was to analyze the behavior of oxidative stress and its interplay with CD40L, a protein that is implicated in atherosclerosis, in hypercholesterolemic children. BACKGROUND: Oxidative stress has been suggested to play a major role in premature atherosclerosis. METHODS: Forty-one children with hypercholesterolemia (mean age 9.28 +/- 0.5 years) and 40 children with normocholesterolemia (mean age 9.02 +/- 0.69 years) were matched for gender and age. Within each group, children were classified as having or not having a family history of cardiovascular disease. Serum levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, and plasma levels of soluble CD40L (sCD40L) were measured in each child. In a subgroup of children with high (n = 8) or normal (n = 8) levels of serum cholesterol, platelet p38 mitogen-activated protein (MAP) kinase phosphorylation, a protein involved in the activation of nicotinamide adenine dinucleotide phosphate oxidase, was determined. RESULTS: Children with hypercholesterolemia had higher values of 8-OHdG and sCD40L compared with control subjects (0.55 +/- 0.06 ng/ml vs. 0.21 +/- 0.02 ng/ml, p < 0.001 and 0.55 +/- 0.04 ng/ml vs. 0.19 +/- 0.03 ng/ml, p < 0.001, respectively). A significant correlation between 8-OHdG and sCD40L was observed in children with high (r = 0.676, p < 0.001) or normal (r = 0.878, p < 0.001) levels of cholesterol. Children with a family history of cardiovascular disease tended to have higher values of 8-OHdG and sCD40L, but the difference was not significant. Analysis of platelet p38 MAP kinase showed that it was phosphorylated more in children with hypercholesterolemia compared with control subjects (36.8 +/- 5.8 AU vs. 8.0 +/- 4.5 AU, p < 0.001 respectively). CONCLUSIONS: Children with hypercholesterolemia have an early increase of oxidative stress that may be responsible for up-regulation of CD40L and potentially predispose to premature atherosclerosis.     

Inverse correlation between soluble CD40 ligand and soluble CD40 is absent in patients with unstable angina

The CD40/CD40 ligand (CD40L) system mediates inflammatory processes important in atherogenesis and plaque instability. The expression of CD40L on activated T cells was suppressed by soluble CD40 (sCD40) in vitro. However, the relationship between soluble CD40L (sCD40L) and sCD40 in unstable angina (UA) is still unknown. Thirty-seven consecutive patients with recent chest pain or discomfort were recruited. Patients with both Braunwald's class IB–IIIB and with coronary stenosis (or stenoses) of >75% were assigned to the UA group (n = 19, aged 67.2 ± 8.2 years), and the rest to the control group (n = 18, aged 63.4 ± 8.7 years). The serum levels of sCD40L and sCD40, and the plasma levels of matrix metalloproteinase (MMP)-9, were measured by enzyme-linked immunosorbent assays. A significantly inverse correlation between sCD40L and sCD40 was shown in the controls (r = −0.72, P = 0.0007), but was absent in the UA group (r = −0.16, P not significant), although there was no statistical significance between these groups in terms of serum levels of sCD40L or sCD40. The difference of the regression slopes of these regression lines was statistically significant (P < 0.01). Additionally, there was a significant correlation between sCD40 and plasma levels of MMP-9 in the patients with and without UA (r = 0.58, P = 0.0096), but no significant correlation between sCD40L and MMP-9 levels (r = 0.00, P not significant). The balance between CD40 and CD40L may be lost in patients with UA. Soluble CD40 expression may also be related to MMP-9 expression in atherosclerotic tissues.     

Impact of nasal continuous positive airway pressure therapy on markers of platelet activation in patients with obstructive sleep apnea

BACKGROUND: Considerable evidence implicates CD40 signaling in the pathogenesis of atheromas. Exposure to CD40 ligand induces platelet-leukocyte conjugation, a heightened expression of inflammatory cytokines, matrix-degrading enzymes, and procoagulant factors. OBJECTIVES: To investigate the association between plasma soluble CD40 ligand (sCD40L) and platelet-monocyte aggregates in patients with obstructive sleep apnea (OSA) and to determine whether treatment of OSA with nasal continuous positive airway pressure (nCPAP) alters this relationship. METHODS: Twelve patients with OSA who were free of other diseases and 12 healthy controls matched for age, gender, and body mass index had blood drawn for sCD40L and platelet-monocyte aggregate measurements. A repeat assessment was obtained following 8 weeks of nCPAP therapy. RESULTS: Subjects with OSA had significantly higher plasma sCD40L levels and exhibited elevated platelet-monocyte aggregates compared to nonapneic subjects (7.6 +/- 4.3 versus 1.7 +/- 1.1, p = 0.004; and 41.3 +/- 23.7 versus 6.7 +/- 4.9, p = 0.001, respectively). Both parameters correlated positively with the percentage of time spent with SpO(2) <90% (r = 0.69, p = 0.01 and r = 0.6, p = 0.03, respectively). After 8 weeks of nCPAP treatment, sCD40 levels declined by 47% (p = 0.003) and platelet-monocyte aggregates by 42% (p = 0.002). None of the controls showed any changes in either sCD40L or platelet- monocyte aggregates after nCPAP therapy. CONCLUSIONS: OSA is associated with upregulation of circulating sCD40L levels and platelet-monocyte aggregation that may account for the increased incidence of cardiovascular events in this population. Treatment with nCPAP may alleviate this risk.     

Soluble CD40 ligand and atrial fibrillation: relationship to platelet activation, and endothelial damage/dysfunction

Increased plasma soluble CD40L (sCD40L) is present in many cardiovascular diseases and predicts poor outcome, but levels in atrial fibrillation (AF) are unknown. Although the platelet is frequently cited as the source of sCD40L, this view is not universal. We hypothesised (a) raised sCD40L in non-rheumatic AF, and (b) that sCD40L correlates with platelet, but not endothelial, markers, thus suggesting a platelet origin. Plasma sCD40L, platelet marker soluble P-selectin and endothelial markers von Willebrand factor (vWf) and soluble E-selectin were measured by ELISA in 54 AF patients free of diabetes or major cardiovascular disease, and in 28 age/sex matched controls. Median (inter-quartile range) sCD40L in AF was 0.82 (0-4.8) ng/mL compared to 0.21 (0-5.5 ng/mL) in controls (p=0.0397). vWf and soluble P-selectin (p<0.005), but not soluble E-selectin, were raised in AF, but none of the indices inter-correlated significantly. We find that sCD40L is marginally raised in AF but the stimulus for this is unclear. The lack of clear correlation with relevant plasma markers suggests that the source is unlikely to be the endothelium or platelet alone.     

Cilostazol could ameliorate platelet responsiveness to clopidogrel in patients undergoing primary percutaneous coronary intervention.

BACKGROUND: Cilostazol increases the cyclic adenosine monophosphate levels in platelets and might ameliorate the antiplatelet activity of clopidogrel. This study investigated the additional effect of cilostazol on platelet aggregation measured by a VerifyNow analyzer and soluble CD40 ligand (sCD40L) as a marker of activated platelet in patients undergoing primary percutaneous coronary intervention (PCI). METHODS AND RESULTS: Sixty cases of primary PCI were randomly assigned to dual (aspirin and clopidogrel) or triple (dual plus cilostazol) therapy. The antiplatelet effects of aspirin and clopidogrel were evaluated by VerifyNow tests. The plasma sCD40L levels at admission, 24 h and 21 days were measured by the ELISA method. The arachidonic acid induced platelet aggregation was similar in both groups. However, the triple group had a significantly lower P2Y12 reaction unit (dual 208.8+/-69.0 vs triple 168.2+/-79.2, p=0.041) and higher % inhibition of adenosine diphosphate (ADP)-induced platelet aggregation (dual 23.8+/-21.4% vs triple 40.5+/-21.0%, p=0.004). In the multivariate analysis, cilostazol was a negative predictor for low responders to clopidogrel (95% confidence interval 0.067-0.711). The plasma sCD40L levels were not significantly different between the 2 groups at the same point of time. CONCLUSIONS: The addition of cilostazol to the combination of aspirin plus clopidogrel significantly increases the inhibition of ADP-induced platelet aggregation. However, there was no additive effect on aspirin-induced antiplatelet activity or lowering of sCD40L.     

Abnormal soluble CD40 ligand and C-reactive protein concentrations in hypertension: relationship to indices of angiogenesis

BACKGROUND: Abnormal inflammation, platelets and angiogenesis are involved in the pathophysiology of cardiovascular disease (CVD). OBJECTIVE: To test the hypothesis that concentrations of high sensitive C-reactive protein (CRP, an index of inflammation) and soluble CD40 ligand (sCD40L, an index of platelet activation) would be abnormal in hypertension, and in turn, be related to plasma indices of angiogenesis, the angiopoietins-1 and -2, and vascular endothelial growth factor (VEGF), in addition to the presence or absence of CVD. METHODS: Using a cross-sectional approach, we measured plasma concentrations of CRP, sCD40L, VEGF, and angiopoietins-1 and -2 in 147 patients with hypertension (85 with a history of CVD event/s, 62 CVD event-free) and 68 age- and sex-matched healthy controls. RESULTS: Concentrations of sCD40L (P = 0.039), CRP (P < 0.001), angiopoietin-1 (P < 0.001), angiopoietin-2 (P = 0.003) and VEGF (P < 0.001) were all greater amongst hypertensive patients than in controls. There were no significant differences in sCD40L and VEGF concentrations between hypertensive individuals with and without CVD events, but CRP and angiopoietin-1 concentrations were significantly greater amongst those with CVD events. On multiple regression analysis, sCD40L was associated with angiopoietin-2 (P = 0.01) and VEGF (P = 0.007) in hypertensive individuals, but no such associations were found within the healthy control group. CONCLUSION: In patients with hypertension, sCD40L was associated with increased circulating markers of abnormal angiogenesis (angiopoietin-2, VEGF). The interaction between sCD40L and angiogenesis may contribute to the pathophysiology of CVD in hypertension.     

Increased circulating platelet-neutrophil, platelet-monocyte complexes, and platelet activation in patients with ulcerative colitis: a comparative study

It is reported that the incidence of thromboembolism is increased in ulcerative colitis (UC), and hypercoagulability persists even when patients are in remission. We evaluated the association of inflammatory response parameters with UC activity, and activation parameters of the platelets, endothelium, and the coagulation system in UC. Eighteen UC patients and 19 healthy subjects were included in the study. The patients' clinical features were recorded down; whole blood counts and acute phase parameters were evaluated. UC patients were divided into two as active (9 patients) and inactive (9 patients) according to combined clinical activity index (CAI) and endoscopic activity index (EAI) scores. In all subjects, platelet CD62P expression, platelet-monocyte complexes (PMC), platelet-neutrophil complexes (PNC), and platelet microparticles (PMP) were determined by flow cytometry. E-selectin, thrombin-antithrombin complex (TAT) levels in plasma, and sCD40L levels in serum were determined by ELISA. In both active and inactive UC patients, platelet CD62P expression, the percentages of PMC, and PNC were significantly higher than those in the control group (P< 0.01). PMP level was higher in the control group than in inactive UC patients (P = 0.001). sCD40L level was significantly higher in active UC group than in the control group (P < 0.01). EAI score correlated significantly with PMP (r = 0.5, P = 0.04) and sCD40L (r = 0.48, P = 0.044); CAI score had a negative correlation (r = -0.68, P = 0.002) with sE-selectin level. In addition to increased CD62P expression and sCD40L, increased formation of PMC and PNC suggests a role for platelet-leukocyte complex formation together with platelet activation in thromboembolic events observed in UC.     

Different behaviour of soluble CD40L concentrations can be reflected by variations of preanalytical conditions.

INTRODUCTION: Biomarkers reflecting an inflammatory or immunological response are increasingly offered to improve the risk stratification of patients. For example, current evidence suggests that soluble CD40 ligand (sCD40L) is elevated in patients with acute coronary syndrome. But only a few data are available to evaluate the influence of preanalytic conditions on sCD40L values. METHODS: Blood samples of seven healthy blood donors were collected in tubes without additives and in EDTA- or citrate-filled tubes at various storage conditions. Platelet count was modified by serum dilution, and sCD40L was measured in platelet-rich-plasma and in whole blood. sCD40L levels were determined by an commercially available ELISA-Kit. RESULTS: Immediately after blood sample assessment, sCD40L levels in serum samples were elevated (1258+/-820 pg/ml) compared to EDTA (64+/-32 pg/ml) and citrate (60+/-8.5 pg/ml) values. Additionally, sCD40L levels were dependent on storage duration. After platelet activation, sCD40L levels were significantly increased to 8278+/-2453 pg/ml and were significantly correlated to platelet count (r=0.96). CONCLUSIONS: Soluble CD40L levels were clearly influenced by preanalytical conditions and were dependent on storage duration, sample technique and platelet count. These influences should be considered by the determination and evaluation of sCD40L concentrations.     

Soluble CD40 ligand, platelet surface CD40 ligand, and total platelet CD40 ligand in atrial fibrillation: relationship to soluble P-selectin, stroke risk factors, and risk factor intervention

BACKGROUND: Abnormal levels of soluble CD40 ligand (sCD40L) have been reported in patients with hypertension, coronary artery disease, diabetes mellitus, heart failure, and stroke, all of which are conditions that are associated with nonvalvular atrial fibrillation (AF). We hypothesized the following: (1) CD40 ligand (CD40L)-related indexes (ie, platelet surface expressed CD40L, the soluble fragment of CD40L [sCD40L], and the total amount of CD40L per platelet [pCD40L]) are elevated in patients with AF compared to control subjects; (2) these indexes correlate with soluble P-selectin (sP-selectin), which is an established platelet marker; and (3) these indexes differentiate "high-risk" from "low-risk" subjects. METHODS: We performed a case-control study of 121 AF patients, 71 "disease control subjects," and 56 "healthy control subjects." Peripheral venous levels of platelet surface-expressed CD40L were analyzed by flow cytometry, while levels of sCD40L, pCD40L, and sP-selectin were measured by enzyme-linked immunosorbent assay. RESULTS: AF patients had significantly higher sCD40L levels compared to healthy control subjects (p = 0.042), with no difference in platelet surface CD40L and pCD40L levels. A positive correlation was noted between levels of sCD40L and pCD40L, and not with sP-selectin. CD40L-related indexes failed to distinguish between high-risk and low-risk AF patients. AF patients receiving optimal antithrombotic therapy had significantly lower pCD40L levels (p < 0.001) compared to control subjects. Optimized AF management also resulted in significant reductions in the levels of sCD40L (p = 0.023) and pCD40L (p < 0.001). CONCLUSION: CD40L-related indexes are not useful in the risk stratification of AF patients, and abnormal sCD40L levels can be reduced by intense multifactorial risk management. While there is a significant, albeit modest, excess of platelet activation in AF patients (as measured by sCD40L levels) compared to healthy control subjects, this is not in excess of that seen in patients with underlying cardiovascular diseases.     

The proinflammatory mediator CD40 ligand is increased in the metabolic syndrome and modulated by adiponectin

OBJECTIVES: We hypothesized that the CD40/CD40 ligand (CD40L) system is up-regulated in the metabolic syndrome (MS) and modulated by adiponectin (AN). The objectives were: 1) to compare plasma and monocyte CD40L in patients with MS and controls and its association with clinical and biochemical parameters, 2) to investigate platelets as a source of soluble CD40L (sCD40L), and 3) to analyze the effects of AN on CD40/CD40L. METHODS: Plasma sCD40L and AN were measured in 246 controls and 128 patients with MS by ELISA. Monocyte CD40/CD40L expression and platelet CD40L content and release were compared in patients with MS and controls. Monocytes and endothelial cells were cultured with AN and CD40/CD40L expression determined by real-time RT-PCR and Western blotting. RESULTS: Patients with MS had higher sCD40L and lower AN levels than controls (0.89 +/- 0.1 vs. 0.76 +/- 0.07 ng/ml and 10.10 +/- 0.65 vs. 12.99 +/- 0.80 microg /ml, P < 0.05). Monocyte CD40/CD40L expression was higher (P < 0.05) in patients than controls (CD40: 1.31 +/- 0.31 vs. 0.80 +/- 0.14 arbitrary units; CD40L: 1.24 +/- 0.85 vs. 0.43 +/- 0.14 pg/microg protein). No differences were observed on CD40L content between resting platelets from patients with MS and controls (7.7 +/- 3.5 vs. 7.2 +/- 2.2 pg/microg protein). Stimulated platelets from patients with the MS released more (P < 0.05) sCD40L than controls (582 +/- 141 vs. 334 +/- 60% change vs. nonstimulated platelets). AN reduced CD40L mRNA and protein expression in monocytes from MS patients and endothelial cells. CONCLUSIONS: The enhanced sCD40L and cellular CD40L expression in the MS suggests that CD40L is of pathophysiological relevance in MS. Also, a new antiinflammatory effect of AN is described through the modulation of the CD40/CD40L system.     

The effects of simvastatin, losartan, and combined therapy on soluble CD40 ligand in hypercholesterolemic, hypertensive patients

The proinflammatory mediator CD40 ligand plays an important role in atherogenesis. Biological mechanisms underlying statin and angiotensin II type 1 receptor blocker therapies differ. Therefore, we compared the effects of these therapies either alone or in combination on plasma soluble CD40 ligand (sCD40L). This was a randomized, double-blind, placebo-controlled cross-over trial with three treatment arms (each 2 months) and two washout periods (each 2 months). Forty-seven hypertensive, hypercholesterolemic patients were given simvastatin 20mg and placebo, simvastatin 20mg and losartan 100mg, or losartan 100mg and placebo daily during each 2 month treatment period. Simvastatin alone did not significantly reduce sCD40L levels relative to baseline measurements when the entire cohort was analyzed. However, simvastatin significantly reduced sCD40L levels from 5.10+/-0.34 to 3.07+/-0.43ng/ml (P=0.002) in a subgroup of 18 patients with high baseline sCD40L levels >2.95ng/ml. Combined therapy or losartan alone significantly decreased plasma sCD40L levels relative to baseline measurements by 14+/-7% (P=0.001) and 13+/-10% (P=0.001), respectively. These decreases were significantly greater than those observed with simvastatin alone (P=0.023 by ANOVA). Significant inverse correlations between baseline sCD40L levels and percent changes in sCD40L levels were observed (r=-0.456, P=0.001 after simvastatin alone; r=-0.476, P<0.001 after combined therapy; r=-0.451, P=0.002 after losartan alone). Losartan alone or combined therapy significantly reduced plasma sCD40L levels more than simvastatin alone in our subjects. Simvastatin, losartan and combined therapy significantly reduced sCD40L to the greatest extent in patients with high baseline sCD40L levels.     

Relationship between plasma inflammatory markers and platelet aggregation in patients with clopidogrel resistance after angioplasty

We evaluated the relationship between plasma inflammation markers and clopidogrel resistance in patients after stent implantation. The plasma levels of C-reactive protein (CRP), P-selectin, platelet soluble CD40 ligand (sCD40L), interleukin 6 (IL-6) and platelet aggregation were measured in 352 patients undergoing percutaneous coronary intervention (PCI) at baseline and after 6 months. The plasma levels of CRP, P-selectin, sCD40L, IL-6 was higher in 65 (18.5%) patients with clopidogrel resistance than in those with normal responsiveness at 6 months after PCI. There was a significant positive correlation between soluble CD40L levels and platelet aggregation (r = .28, P < .05). Diabetes (DM) and sCD40L level were independent predictors for unresponsiveness after stent implantation according to stepwise multivariate analyses. The hazard ratio (HR) for sCD40L level was 3.02 (95% CI = 1.28 to 3.25; P = .036) and for DM 2.53 (95% CI = 1.28 to 6.55, P = .03). We conclude that sCD40L and DM may influence clopidogrel resistance.     

Increased soluble and platelet-associated CD40 ligand in essential thrombocythemia and reactive thrombocytosis

CD40 ligand (CD40L) is expressed on activated CD4(+) T lymphocytes and at the activated platelet surface. A circulating soluble form of CD40L (sCD40L) is generated by the way of a proteolytic cleavage. We measured sCD40L in the plasma of either healthy subjects; patients with inflammatory disorders and low, normal, or high platelet count (reactive thrombocytosis); or patients with essential thrombocythemia (ET). A tight correlation was found between the platelet count and plasma sCD40L. ET patients had the highest levels of sCD40L. Platelet-associated CD40L was increased in ET and reactive thrombocytosis, conditions associated with increased platelet regeneration. Platelet-associated CD40L was released upon platelet activation. In conclusion, platelets appear as a reservoir of CD40L that may be a major contributor to circulating sCD40L. Platelet-associated CD40L may be a potential marker of platelet regeneration.     

Tumour necrosis factor alpha upregulates platelet CD40L in patients with heart failure

AIMS: Patients with heart failure (HF) have elevated values of the pro-inflammatory protein CD40L but the underlying mechanism is unclear. This study was performed to evaluate the interplay between tumour necrosis factor alpha (TNFalpha) and CD40L in HF. METHODS AND RESULTS: In patients with HF (n=86) and healthy subjects (HS, n=43), plasma levels of soluble CD40L (sCD40L), TNFalpha, soluble receptors of TNFalpha such as soluble TNF receptors I and II (sTNFR1 and sTNFR2), and 8OH-dG, a marker of oxidative stress, were determined. Also, an in vitro study was performed by determining platelet CD40L regulation upon platelet stimulation with TNFalpha. Compared with HS, HF patients had higher plasma values of sCD40L, TNFalpha, sTNFR1 and sTNFR2, and higher platelet expression of TNFR1 and TNFR2 with a progressive increase from NYHA I to NYHA IV classification. sCD40L significantly correlated with TNFalpha, sTNFR1, and sTNFR2; plasma levels of TNFalpha significantly correlated with sCD40L. Incubation of platelets from HF patients with a TNFalpha receptor inhibitor significantly decreased platelet CD40L expression. The in vitro study demonstrated that TNFalpha significantly increased CD40L expression, an effect weakly influenced by aspirin but significantly reduced by AACOCF3, an inhibitor of PLA(2), apocynin, an inhibitor of NADPH oxidase, or staurosporine, an inhibitor of PKC. CONCLUSION: The study shows that in HF patients, platelet CD40L is upregulated by TNFalpha via a cyclooxygenase-1-independent, arachidonic acid-mediated oxidative stress mechanism.     

Increased platelet activation markers in rheumatoid arthritis: are they related with subclinical atherosclerosis?

Atherosclerotic cardiovascular mortality is increased in rheumatoid arthritis (RA) patients. We evaluated the association of inflammatory response with platelet, endothelial, coagulation activation parameters; and subclinical atherosclerosis in RA patients. We included 27 RA patients (21 female; six male) and 19 healthy subjects (14 female; five male). Disease activity score (DAS28) in RA patients was calculated; and patients were divided into two groups as active and inactive. Flow cytometry was used to determine platelet CD62P expression, platelet microparticles (PMP), platelet-monocyte (PMC) and platelet-neutrophil complexes (PNC). Plasma E-selectin, thrombin-antithrombin (TAT) complex, and serum sCD40L levels were determined by ELISA. The intima-media thickness (IMT) of carotid arteries was determined by B-mode ultrasonography. In RA patients, platelet CD62P expression (p < 0.001), PMC (p = 0.037) and sCD40L (p < 0.001) levels were increased when compared to the control group. PNC (p = 0.07) and TAT levels (p = 0.1) were non-significantly higher, and PMP level (p = 0.075) was nonsignificantly lower in RA patients. Soluble E-selectin level was significantly higher in the active RA group than in the inactive RA group (p = 0.009). There was no correlation between carotid IMT and activity markers, the evaluated parameters (p > 0.05).The increase in markers of active platelets, CD62P and sCD40L, and PMC levels might be associated with the increased cardiovascular mortality in RA. Nevertheless, none of these parameters were associated with carotid IMT: this suggests that one cross-sectional value might not be a good marker for atherosclerosis     

Thromboxane-dependent CD40 ligand release in type 2 diabetes mellitus.

OBJECTIVES: The goals of this study were to characterize the platelet contribution to soluble CD40 ligand (sCD40L), to correlate its formation with the extent of oxidative stress and platelet activation, and to investigate the effects of improved metabolic control and low-dose aspirin on these processes. BACKGROUND: Inflammation, oxidative stress, and platelet activation are involved in the pathogenesis of type 2 diabetes (T2DM) and its complications. The CD40-CD40L interactions result in inflammatory and pro-thrombotic responses. METHODS: Urinary 8-iso-prostaglandin (PG)F2alpha and 11-dehydro-thromboxane (TX)B2, in vivo markers of oxidative stress and platelet activation, respectively, plasma CD40L, and C-reactive protein (CRP) were measured in 114 T2DM patients and 114 control patients. A randomized, parallel group, 17-day study of aspirin (30, 100, or 325 mg/day) was performed in 18 T2DM patients. A similar study was performed in six healthy volunteers (aspirin, 100 mg/day). Twenty poorly controlled T2DM patients were studied before and after improved metabolic control. RESULTS: Compared with control patients, diabetic patients showed significantly higher levels of 8-iso-PGF2alpha, 11-dehydro-TXB2, sCD40L, and CRP. On multiple regression analysis, 11-dehydro-TXB2 and 8-iso-PGF2alpha excretion rates predicted sCD40L levels. Soluble CD40L linearly correlated with 11-dehydro-TXB2 (rho = 0.67, p < 0.0001), and both were reduced after one week of aspirin (p < 0.0026), with slow recovery over 10 days after aspirin withdrawal. Improved metabolic control was associated with a reduction in sCD40L, 8-iso-PGF2alpha, and 11-dehydro-TXB2. CONCLUSIONS: This study provides several lines of evidence for the dependence of sCD40L release on TXA(2)-dependent platelet activation in T2DM and provides novel mechanistic insight into the amplification loops of persistent platelet activation in this setting.     

CD40配体高表达与不稳定型心绞痛之间的关系

为了探讨不稳定型心绞痛患者外周血单核细胞表达CD40配体及血清可溶性CD40配体变化的临床意义。应用间接免疫荧光流式细胞术和双抗夹心酶联免疫测定法分别对正常对照组 16例、稳定型心绞痛 2 0例、不稳定型心绞痛 2 0例患者血单核细胞表达CD40配体及血清可溶性CD40配体水平进行检测。并观察血清可溶性CD40配体与冠状动脉病变程度的关系。结果发现 ,(1)不稳定型心绞痛组血单核细胞表达CD40配体明显较稳定型心绞痛组和对照组高 (P <0 .0 1) ,稳定型心绞痛组与对照组相比无差异 (P >0 .0 5 )。 (2 )不稳定型心绞痛组血清可溶性CD40配体水平明显较稳定型心绞痛组和对照组高 (P <0 .0 1) ,而稳定型心绞痛组与对照组相比亦有明显差异 (P <0 .0 5 )。 (3)经皮冠状动脉腔内成形术后血清可溶性CD40配体明显高于术前 (P <0 .0 1) ,但血单核细胞表达CD40配体无差异 (P >0 .0 5 )。 (4 )血清可溶性CD40配体水平与冠状动脉病变的复杂狭窄数相关 (r=0 .5 4,P <0 .0 1) ,而与狭窄的程度和范围无关。此结果提示 ,血清可溶性CD40配体升高对冠状动脉斑块的不稳定或破裂起重要作用 ,且可能是冠状动脉病变的活动性标志物。     

Circulating soluble CD40 ligand mediates the interaction between neutrophils and platelets in acute coronary syndrome

Following plaque rupture, activated platelet will induce subsequent inflammatory process including neutrophil recruitment. In vitro study demonstrated an interaction between neutrophils and platelets via a mechanism involving CD40-CD40 ligand. However, whether this mechanism exists in the clinical setting remains unknown. Fifty-four patients with acute myocardial infarction (AMI) and 25 with unstable angina of pain onset of ≤24 h were enrolled consecutively. Acute myocardial infarction was diagnosed from three diagnostic criteria, i.e., anginal pain, electrocardiogram ST-T changes, and cardiac enzyme elevation. Unstable angina was diagnosed in patients without elevated cardiac enzymes. Peripheral venous blood was drawn at admission for routine blood count and soluble CD40 ligand (sCD40L) measurement. Neutrophil count was determined by an automated blood cell counter. Circulating sCD40L was measured using a standard enzyme-linked immunosorbent assay. Neutrophil count was significantly higher in AMI as compared with unstable angina (P < 0.001), whereas circulating sCD40L did not significantly differ. Despite marked elevation, no correlation was observed between neutrophil count and circulating sCD40L in AMI. Interestingly, we observed a strong and positive significant correlation between neutrophil count and circulating sCD40L level (r = 0.607, P = 0.002) in unstable angina. Circulating sCD40L is associated with neutrophil count and may mediate interaction between neutrophils and platelets in acute coronary syndrome, particularly in unstable angina.     

Relationship between the serum sCD40L level and aspirin-resistant platelet aggregation in patients with stable coronary artery disease

BACKGROUND: Current evidence supports the central role of inflammation in all phases of the atherosclerotic process, including its thrombotic complications. Increased serum sCD40L may trigger platelet activation, so the aim of the present study was to determine the relation between sCD40L levels and aspirin-resistant platelet aggregation in patients with coronary atherosclerosis. METHODS AND RESULTS: A total of 167 consecutive patients (39-85 years old, 35.9% women) with stable coronary artery disease was enrolled in the study. Platelet function was evaluated by a Platelet Function Analyzer 100 device (PFA-100) with collagen and epinephrine (Col/Epi) and collagen and adenosine diphosphate (ADP) (Col/ADP) cartridges. Aspirin resistance was defined as a closure time (CT) <186 s with Col/Epi cartridges, despite regular aspirin therapy. Serum sCD40L level was determined quantitatively with an ELISA method. Fifty-seven (34.1%) patients had aspirin resistance according to the PFA-100. Mean CT measured with the Col/ADP cartridges was 83+/-18 s (65-101 s). Mean serum sCD40L was 157 pg/ml (6-700 pg/ml) in the entire cohort. Patients with aspirin resistance had a mean serum sCD40L level of 166 pg/ml and patients with aspirin-sensitive platelet aggregation had an sCD40L level of 152 pg/ml (p=0.582). CONCLUSION: The sCD40L level is similar in patients with aspirin-resistant and aspirin-sensitive platelet aggregation according to the PFA-100. There is still need for further studies to elucidate the relationship between aspirin-resistant platelet aggregation and sCD40L, which is now known to be prothrombotic, proinflammatory and to be a risk factor for cardiovascular events.