Complement activation by polyethoxylated pharmaceutical surfactants: Cremophor-EL, Tween-80 and Tween-20.

Immunosafety analysis of pharmaceutical surfactants is an important step in understanding the complex mechanisms by which they induce side effects in susceptible patients. This paper provides experimental evidences that polyethoxylated surfactants, Cremophor-EL and Tween-80, also known as Polysorbate-80, activate the complement system in vitro, in normal human serum and plasma. They appeared to be more efficient reactogens than their structural homolog, Tween-20. Cremophor-EL and Tween-80 promoted the generation of biologically active complement products, C3a, C5a and C5b-9. Consistently, Paclitaxel and Taxotere (Docetaxel), pharmaceuticals formulated in Cremophor-EL and Tween-80, activated the complement system in similar extent. Moreover, comparison of serum reactivity against the drug-loaded and drug-free formulations exhibited a significant linear correlation. Taken together, these results are consistent with the hypothesis that therapeutic side effects, such as acute hypersensitivity and systemic immunostimulation, caused by intravenous nanomedicines containing polyethoxylated detergents such as Cremophor-EL and Tween-80, can be attributed to complement activation-derived inflammatory mediators.

Endothelial cell function in patients with hereditary angioedema: elevated soluble E-selectin level during inter-attack periods.

BACKGROUND: The bradykinin pathway in the pathomechanism of hereditary angioedema due to C1-inhibitor deficiency (henceforward "hereditary angioedema") has been thoroughly studied; however, much less is known about endothelial cell function. Enhanced endothelial cell permeability is obvious during edematous attacks, but not during inter-attack periods. Our knowledge about other endothelial characteristics is even more incomplete. OBJECTIVE: Therefore the aim of this study was to characterize endothelial cell function in hereditary angioedema patients during symptom-free, inter-attack periods. METHODS: We measured the serum levels of soluble E-selectin, endothelin-1, and von Willebrand factor along with collagen-binding activity in 49 hereditary angioedema patients and in 50 healthy controls. RESULTS: Endothelin-1 and von Willebrand factor level, as well as its collagen-binding activity, were similar in hereditary angioedema patients and in controls; however, we found elevated soluble E-selectin levels in the patients. Interestingly, soluble E-selectin concentration did not correlate with any of the inflammatory markers or smoking, and it is not the consequence of the known E-selectin/C1-inhibitor interaction (an analytical phenomenon). In a multiple logistic regression model, the difference in soluble E-selectin between hereditary angioedema patients and controls remained highly significant when adjusted for age, gender, smoking, C-reactive protein, and AB0 blood groups. CONCLUSION: These results demonstrate that in hereditary angioedema, the majority of endothelial functions are normal during inter-attack periods; however, soluble E-selectin levels are elevated. The higher soluble E-selectin plasma concentration is unlikely to result from inflammation; rather, it reflects enhanced shedding mechanisms.

Serum soluble E-selectin and NT-proBNP levels additively predict mortality in diabetic patients with chronic heart failure.

BACKGROUND: Neuroendocrine activation with endothelial dysfunction is a key pathophysiological process in chronic heart failure (CHF). Although increased soluble E-selectin (sE-selectin) levels predict adverse events in several forms of cardiovascular disease, there are only scarce data on its predictive value in CHF. The aim of our study was to investigate whether sE-selectin is a useful predictor of mortality in CHF patients and whether its predictive power is additive to that of NT-proBNP. METHODS: Plasma levels of sE-selectin were measured by ELISA in 192 CHF patients with clinical systolic heart failure. The study population was followed up for 14.9 months on average; 46 patients died during this period. RESULTS: Levels of sE-selectin were significantly higher in non-surviving patients than in survivors (p = 0.005) and significantly correlated with the following inflammatory markers: CRP (r = 0.242, p = 0.001), TNF-α (r = 0.201, p = 0.005), TNF-RII (r = 0.207, p = 0.004), and IL-6 (r = 0.339, p < 0.0001). According to Cox regression analysis of the prediction power of sE-selectin for all-cause mortality, high sE-selectin levels independently and significantly predicted short-term mortality in CHF (HR 1.47, 95% CI 1.103-1.956). Furthermore, sE-selectin predicted mortality in CHF patients with concomitant diabetes mellitus, as well as simultaneously elevated sE-selectin and NT-proBNP levels additively predicted mortality. CONCLUSIONS: This study demonstrated a weak correlation of sE-selectin level with inflammatory markers and prediction of short-term mortality in diabetic CHF patients. Elevated serum sE-selectin levels and concomitantly increased NT-proBNP concentrations have additive predictive power in CHF. This suggests that parallel activation of various pathophysiological pathways confers increased risk of adverse outcome in CHF.

Proinflammatory activation pattern of human umbilical vein endothelial cells induced by IL-1ß, TNF-α, and LPS.

Endothelial cells play a critical role in inflammation by responding to several endogenous and exogenous proinflammatory stimuli. The three most studied factors that provide inflammatory signals to endothelial cells are lipopolysaccharide (LPS), tumor necrosis factor (TNF)-α, and interleukin (IL)-1ß; however, their effects on endothelial cells were thoroughly compared at the level of gene expression only. Therefore, our aim was to assess the differences in the signaling pathways, adhesion molecules, and cytokines induced by proinflammatory factors in human umbilical vein endothelial cells (HUVEC). In this study, we demonstrated that signaling of LPS was less effective than that of IL-1ß, and was significantly slower than that ofTNF-α and IL-1ß, which can be partially explained by the special localization of Toll-like receptor 4 (TLR4). We showed that TLR4 is mainly localized in Golgi apparatus in HUVEC. The proinflammatory capacity of TNF-α was similar to that of IL-1ß in inducing NF-κB nuclear translocation, while IL-1ß was the strongest activator of MAPK pathways. Moreover, expression of E-selectin, IL-6, and IL-8 was induced most efficiently by IL-1ß, while LPS and TNF-α had less effect, whereas we did not find such a difference in ICAM-1 and MCP-1 expression. Due to the higher induction of E-selectin and IL-8, IL-1ß might have more important role in neutrophil recruitment than LPS and TNF-α. By above-mentioned parameters we identified a signaling and expression pattern for the three proinflammatory molecules. This pattern illustrates how complex a proinflammatory process can be, and may enable us to predict and compare the pathomechanism of various inflammatory diseases.