Certain batches of albumin solutions influence the expression of endothelial cell adhesion molecules

Objective: Increased levels of soluble adhesion molecules, a decreased PO2/FIO2 ratio and a tendency to worsened outcome have been reported following the use of human albumin in critical illness. The reasons are not yet understood. Since albumin solutions have previously been shown to contain proinflammatory mediators, a direct upregulation of adhesion molecules by contaminated batches may explain these findings. To examine this, we studied the effects of different albumin preparations on endothelial cell adhesion molecules in vitro. Design: Experimental study. Setting: Laboratory for cell biology. Methods: Human umbilical venous endothelial cell cultures (n = 4) were incubated for 6 h at 5 mg/ml with four different human albumin solutions (HA1-4) from different manufacturers. Medium served as the control. Using flow cytometry, the effects on E-selectin, ICAM-1 and VCAM-1 expression were determined on unstimulated cells and on cells stimulated with tumour necrosis factor alpha at 0.5 ng/ml for 4 h. Measurements and results: On unstimulated cells, HA1 and HA4, two different batches from the same manufacturer, increased ICAM-1 by 22 % and 15 %, respectively. After stimulation, both solutions resulted in a 19 % increased expression of E-Selectin. In addition, HA4 decreased VCAM-1 on stimulated cells (p less than or equal to 0.05). Two albumin preparations from other manufacturers did not produce significant effects. Conclusions: Some albumin solutions directly modulate adhesion molecule expression on endothelial cells. This may, at least in part, explain the previous finding of increased soluble adhesion molecules and a decreased PO2/FIO2 ratio in critically ill patients undergoing volume replacement with human albumin.