SDC1 and endothelial dysfunction: On the other hand, the effect of the epicatechin-enriched regime on two markers of the glycocalyx and endothelial dysfunction, TNF-α, a proinflammatory, immunomodulator, and proapoptotic cytokine, and syndecan-1, a transmembrane protein member of the heparan sulfate proteoglycan family involved in the synthesis of heparan sulfate and other proteoglycans and a marker of endothelial glycocalyx degradation, is shown in Figure 4.