Summary
Although glucocorticoids are widely used in a number of inflammatory disorders associated
with endothelial and platelet activation, their effect on the endothelium and platelets
in humans remain poorly defined. Hence, we measured changes of a specific endothelial
cell marker (von Willebrand factor [vWF]) and of a platelet marker (soluble P-selectin)
by infusing therapeutic doses of dexamethasone (0.04 mg/kg and 1.0 mg/kg b.i.d on
two days) or placebo into nine healthy men. Venous citrated plasma was obtained before
infusion, and at 24 and 48 h. Compared to baseline levels, we found increased levels
of vWF at both time points at the higher dose (p=0.011). Plasma levels of sP-selectin
rose at 48 h after the high dose (p=0.017). Human umbilical endothelial cells were
cultured in the presence or absence of de-xamethasone (0, 0.01, 1 μM), to determine
the possible mechanism for the increase in vWF. The vWF-mRNA levels as quantified
by RT-PCR increased 2-fold (p<0.05), and the vWF-concentrations in cell lysates increased
by 38% (p<0.05), whereas the vWF-concentrations in the supernatants were unaffected.
In summary, high dose DEXA increases sP-selectin and vWF. The probable underlying
mechanism for the latter was a DEXA induced up-regulation of vWF-mRNA transcription.
Together, this indicates that high dose glucocorticoids may enhance haemostasis, which
could be beneficial under certain conditions, but which may also contribute to adverse
vascular events by increasing platelet activation and vWF dependent thrombosis.
Keywords
Von Willebrand factor - P-selectin - dexamethason - randomised controlled trial