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Background: Increasing evidence shows that CD40–CD40L interaction plays a crucial role in the pathogenesis of atherosclerosis and coronary artery disease. The mechanism of CD40–CD40L interaction might be related to signal transduction via receptor. The transduction pathway of the CD40 receptor may involve the activation of phospholipase C (PLC) which induces the production of inositol trisphosphate (IP3) leading to the increase of the intracellular free calcium on one hand, and of diacylglycerol (DAG) which stimulates the translocation to the membrane of protein kinase C (PKC). Methods: Endothelial cells were isolated from human umbilical vein and incubated with indicated concentrations of CD40 ligand (CD40L) for various periods. The DAG levels in HUVEC were studied with radioenzymatic assay. Quantitative measurements of 32P phosphatidic acid were performed by thin-layer chromatography and autoradiography. IP3 was quantitatively measured by the radioreceptor binding assay. The activity of PKC and [Ca2+]i induced by CD40L were measured by its ability to transfer phosphate from [γ-32P]ATP to lysine-rich histone and flow cytometric analysis loading with the Ca2+ dye fluo3/Am, respectively. Results: The DAG levels were raised by CD40L in a dose-dependent, biphasic manner. The early phase was rapid and transient, peaking at 20 s; and the late phase reached the maximal level at 10 min and then decayed slowly. CD40L increased the PKC total activity in a dose-dependent manner with phase peaking at 12 min, then decreased slowly and maintained for at least 20 min. The results also showed that CD40L induced PKC activity translocation from the cytosolic to membrane. Similarly, the CD40L-induced transient IP3 formation was coincident with the first peak of DAG formation. Moreover, CD40L also induced biphasic [Ca2+]i responses including the rapid initial transient phase and the sustained phase. Anti-CD40 monoclonal antibody can significantly suppress CD40L-induced DAG–PKC and IP3–[Ca2+]i signal pathway activation in HUVEC. Conclusions: CD40–CD40 ligand interaction can induce a robust stimulation of the DAG–PKC and inositol trisphosphate–Ca2+ signal transduction pathway in HUVEC. [Copyright &y& Elsevier]

Abstract: Background: Although it has been hypothesized that hypertension is in part an inflammatory disorder, clinical data linking inflammation with incident hypertension are scarce. There is evidence that have shown that CD40–CD40L interaction plays a pathogenic role in inflammatory disorders. We assessed whether CD40 system expressions were altered in patients including 30 with hypertension grade 1, 80 with hypertension grade 2 and 40 with hypertension grade 3. Methods: Twenty normal controls and 150 patients with essential hypertension were investigated. The expression of CD40 and CD40L on platelet was analyzed by indirect-immonofluorescence flow cytometry and soluble CD40L level was determined by a commercially available ELISA. C-reactive protein was also measured by ELISA. Results: All patients with hypertension showed a significant increase of CD40 (67.1±9.6 Mean Fluorescence Intensity, MFI) and CD40L (15.3±5.0 MFI) coexpression on platelets as well as sCD40L levels (12.8±3.9 ng/ml ) compared with controls (p<0.0001). We found that CRP levels related to CD40–CD40L system. We also observed a slight correlation between sCD40L level and blood pressure. During 3 months follow-up, patients with enhanced levels of sCD40L (>15 ng/ml) indicated a tough control of blood pressure. Conclusion: Patients with essential hypertension show increased coexpression of CD40 system, which suggests that hypertension is in part an inflammatory disorder. [Copyright &y& Elsevier]

Background: Increasing evidence shows that high expression of CD40L plays an important role in the pathogenesis of atherosclerosis and coronary artery disease. We evaluated the clinical predictive value of increased serum soluble CD40 ligand (CD40L) in patients with acute coronary syndromes (ACS) and acute chest pain. Methods: Serum levels of soluble CD40 ligand were measured by ELISA in 128 patients with ACS and in 68 patients with acute chest pain. Platelet activation was assessed by flow cytometry. Results: The levels of soluble CD40 ligand were increased in 57.8% patients with ACS (>8.0 ng/ml) and in 35 patients with acute chest pain (>8.0 ng/ml), respectively. The level of soluble CD40 ligand was slightly correlated with measured levels of troponin T (r=0.21, p<0.05), and the increased soluble CD40L levels (>8.0 ng/ml) were associated with higher risk for AMI, sudden death and recurrent angina. Patients with elevated serum levels of sCD40L and cTnT showed a significantly increased risk of major adverse cardiovascular events (including AMI, sudden death and recurrent angina) in the two groups during 30 days and 6 months of follow-up. Conclusion: In patients with unstable coronary artery disease, elevation of serum soluble CD40L levels indicated an independent increased risk of major adverse cardiovascular events. [Copyright &y& Elsevier]