The sCD40L (A) and sVCAM-1 (B) levels in patients carrying the MTHFR C677T genotype with hyperhomocysteinemia (>15 µmol/l) or normal homocysteinemia (<15 µmol/l). Dots represent individual measurements. Horizontal lines represent median value. Differences between the 2 groups were determined using the Mann-Whitney U test. MTHFR = 5,10 methylene tetrahydrofolate reductase; sCD40L = soluble CD40 ligand; sVCAM = soluble vascular cell adhesion molecule.

Correlation between plasma levels of homocysteine (A) or sVCAM-1 (B) and sCD40L in all included subjects. Dots represent individual measurements. For correlation analysis, the Pearson correlation coefficient was calculated. The insight scatterplots represent the correlation of untransformed variables. Log homocysteine = logarithmic transformation of homocysteine; Log sCD40L = logarithmic transformation of plasma sCD40L; Log sVCAM-1 = logarithmic transformation of sVCAM-1; other abbreviations as in Figure 1.

(A) The left panel shows untreated cells. The dashed histogram represents the irrelevant antibody; the green histogram depicts the anti-CD40 antibody. The middle and right panels show HUVECs exposed to respectively 50 µM or 500 µM Hcy for 24 h. Green histograms indicate untreated cells, open histograms depict Hcy-treated cells. Each histogram is representative of at least 3 experiments and shows cell numbers (y axis) versus log fluorescence intensity (x axis) for 6.000 viable cells. (B) Increase in CD40 expression by Hcy in HUVECs is concentration dependent. Cells were exposed to increasing concentrations of Hcy (10, 25, 50, 100, 500 µM) for 12 h, and CD40 expression was evaluated by flow cytometry. Results are from a representative experiment. (C) The graph summarizes results from 3 to 5 different experiments with HUVECs exposed to the indicated concentrations of Hcy for 12 h or 24 h. Data are expressed as mean ± SD of percent of total events. (D) Western blot analysis. The HUVECs were exposed to the indicated concentrations of Hcy for 12 h. The upper panel shows a representative blot. The lower panel depicts mean ± SD of densitometric analyses from 3 separate experiments. Results were normalized for ß-actin. Ctrl = control; FL1 = fluorescent channel 1; Hcy = homocysteine; HUVECs = human umbilical vein endothelial cells.

The HUVECs were exposed to either vehicle control (Ctrl) or Hcy (500 µM) for the indicated time. The CD40 messenger ribonucleic acid (mRNA) expression was evaluated by real-time polymerase chain reaction. Relative CD40 abundance was calculated using glyceraldehyde-3-phosphate dehydrogenase as gene of reference and the equation 2^–Ct. Data points are mean ± SD from 3 independent experiments. Abbreviations as in Figure 3.

The HUVECs were exposed to vehicle control or to 100 µM Hcy for 24 h and then incubated with 500 ng/ml CD40L for 6 h. Cells were harvested, and VCAM-1 expression was measured by flow cytometry. (A) (Left panel) Dotted line = irrelevant antibody; filled histogram = vehicle-treated cells; open histogram = cells treated with Hcy. (Center panel) Filled histogram = vehicle-treated cells; open histogram = cells exposed to CD40L. (Right panel) Filled histogram = vehicle-treated cells; open histogram = cells treated with Hcy + CD40L. (B) Bars represent mean ± SEM of mean fluorescence intensity (MFI) from 3 independent experiments. Abbreviations as in Figures 1 and 3.

(A) The upper left panel shows untreated cells (the open histogram represents the irrelevant antibody, whereas the blue histogram depicts the anti-CD40 antibody). The upper right panel shows a comparison between untreated cells (blue histogram) and cells treated with H₂O₂ (300 µM) for 30 min (open histogram). Cells were washed and cultured in normal medium for 24 h before flow cytometric analysis (upper panels). The graph in the lower panel shows mean ± SD from 3 different experiments. (B) The upper left panel shows untreated cells (the open histogram represents the irrelevant antibody, whereas the blue histogram depicts the anti-CD40 antibody). The upper right panel shows a comparison between untreated cells (blue histogram) and cells treated with L-cysteine (500 µM) for 12 h. The lower panel shows mean ± SD from 3 separate experiments. Ctrl = control; other abbreviations as in Figure 3.

Platelets (1 x 10⁸ /ml) were exposed to Homocysteine (Hcy) (500 µM) or thrombin (Thr) (0.2 U/ml) for 5 min at 37°C and analyzed by flow cytometry. (A) Filled histograms represent untreated cells, whereas open histograms represent cells exposed to Hcy or Thr. Staining with irrelevant nonbinding antibody is indicated by dotted histograms. (B) Bars represent mean ± SD of mean fluorescence intensity (MFI) from 3 independent experiments. Ctrl = control; other abbreviations as in Figure 3.