Consumption of tea is inversely associated with cardiovascular diseases. However, the active compound(s) responsible for the protective effects of tea are unknown. Although many favorable cardiovascular effects in vitro are mediated by epigallocatechin gallate (EGCG), its contribution to the beneficial effects of tea in vivo remains unresolved. In a randomised crossover study, a single dose of 200 mg EGCG was applied in three different formulas (as green tea beverage, green tea extract (GTE), and isolated EGCG) to 50 healthy men. Flow-mediated dilation (FMD) and endothelial-independent nitro-mediated dilation (NMD) was measured before and two hours after ingestion. Plasma levels of tea compounds were determined after each intervention and correlated with FMD. FMD significantly improved after consumption of green tea containing 200 mg EGCG (p < 0.01). However, GTE and EGCG had no significant effect on FMD. NMD did not significantly differ between interventions. EGCG plasma levels were highest after administration of EGCG and lowest after consumption of green tea. Plasma levels of caffeine increased after green tea consumption. The results show that EGCG is most likely not involved in improvement of flow-mediated dilation by green tea. Instead, other tea compounds, metabolites or combinations thereof may play a role.

Background In Systemic Lupus Erythematosus (SLE) various compartments of the immune system are altered. Type I interferon (IFN) produced by plasmacytoid dendritic cells seems to play a central role. The expression of Sialic Acid–Binding Ig-like Lectin 1 (Siglec-1) on monocytes is a cytometrically measurable surrogate parameter for type I IFN and has been shown to correlate with disease activity in SLE. Increased B cell activation is also characteristic for active SLE. Frequencies of CD27++ plasmablasts in peripheral blood are known to be higher in patients with active disease. Type I IFN can promote T cell dependent and independent B cell activation. Objectives To investigate the combined measurement of Siglec-1 expression and plasmablast frequencies as biomarkers for disease activity in human SLE. Methods After informed consent heparinised blood samples along with clinical and paraclinical data were collected from 12 SLE patients. After red cell lysis FACS staining was performed with fluorescent antibodies against CD14, CD3, CD19, CD20, CD27, CD138 and Siglec-1 plus isotype control. Cells were collected and measured using a BD™ LSR II flow cytometer. Data were analysed using FLOWJO analysis software. For Siglec-1 expression on CD14+ monocytes a ratio was calculated dividing the median fluorescence intensity (MFI) value of Siglec-1 stained by the MFI of isotype control stained cells. Plasmablast frequencies where calculated by gating on mononuclear cells according to forward and sideward scatter, further gating on CD19+ CD3- cells and than on CD20-CD27++ or CD20-CD138+ cells, respectively. Results Siglec-1 expression correlated negatively with serum complement (C3) but not with SLEDAI or anti double stranded DNA (dsDNA) antibody titers using the non parametric Spearman test. Both, frequencies of CD20-CD27++ and frequencies of CD20-CD138+ cells correlated negatively with serum complement and positively with SLEDAI but not with dsDNA antibody titers. This was the case for frequencies in CD19+ B cells as well as in lymphocytes. Furthermore, Siglec-1 expression correlated positively with plasmablast frequencies, again for both, CD20-CD27++ and CD20-CD138+ cells. Conclusions All measured parameters (Siglec-1 in monocytes, CD20-CD27++ CD19+ cells and CD20-CD138+ CD19+ cells) seem to be suitable as additional disease activity markers in SLE. The reliability of the single markers and combinations should, of course, be studied in a bigger cohort, and also under various treatment conditions. The correlation of Siglec-1 expression with plasmablast frequencies is a further hint to pathogenetic relations between type I interferon and B cell activation. References Biesen R, Demir C, Barkhudarova F, Grün JR, Steinbrich-Zöllner M, Backhaus M, Häupl T, Rudwaleit M, Riemekasten G, Radbruch A, Hiepe F, Burmester GR, Grützkau A. Sialic acid-binding Ig-like lectin 1 expression in inflammatory and resident monocytes is a potential biomarker for monitoring disease activity and success of therapy in systemic lupus erythematosus. Ar...

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