The effect of resuscitation fluids on neutrophil-endothelial cell interactions in septic shock.

Fluid resuscitation is essential in the treatment of septic shock. This study examined the effect of resuscitative fluids (RFs) on sepsis-induced neutrophil-endothelial cell interactions. The RFs studied were 0.9% saline (NS), Ringer's lactate (RL), 7.5% saline and dextran-70 (DHS), 5% albumin (AL), and 6% hydroxyethyl starch (HS). Platelets and neutrophils were obtained from normal volunteers, and plasma was obtained from patients with septic shock. Microslides coated with human umbilical endothelial vein cell (HUVEC) and platelet-neutrophil solutions were primed with septic plasma with/without the RF. Neutrophil rolling velocity, leukoaggregation, and neutrophil adherence were determined. Separately, platelet-neutrophil solutions and endothelial cells were exposed to septic plasma with/without RFs, and cellular activation, neutrophil superoxide production, and endothelial cell E-selectin expression were assessed. Ringer's lactate decreased neutrophil rolling velocity and increased aggregation and adherence. Normal saline had no effect on these parameters. Hydroxyethyl starch and AL increased neutrophil rolling velocity and decreased adherence and aggregation when HUVECs were preincubated with the RF. Dextran-70 and 7.5% saline decreased neutrophil-endothelial cell interactions in both HUVECs and platelet/neutrophil preincubated experiments. Ringer's lactate increased activation of neutrophils and platelets, whereas AL decreased their activation. Other than NS, all the RFs increased neutrophil superoxide production. Ringer's lactate increased endothelial cell E-selectin release, whereas AL and HS both decreased its release. These data suggest that fluids used in the resuscitation of septic shock vary in their effects on sepsis-induced neutrophil-endothelial cell interactions. Ringer's lactate amplifies the effects of sepsis, while NS appears to have minimal impact. Dextran-70 and 7.5% saline, AL, and HS in varying degrees decrease sepsis-related neutrophil-endothelial cell interactions and activation.

Augmentation of platelet and endothelial cell eNOS activity decreases sepsis-related neutrophil-endothelial cell interactions.

NO is an important mediator of microvascular patency and blood flow. The purpose of this study was to examine the role of enhanced eNOS activity in attenuating sepsis-induced neutrophil-endothelial cell interactions. Microslides coated with human umbilical vein endothelial cells were stimulated with plasma from patients with septic shock. Neutrophil and platelets from control subjects were also stimulated with plasma from patients in septic shock and perfused over stimulated endothelial cells. l-Arginine (LA) with and without NG-monomethyl l-arginine (LNMMA), a nonselective NOS inhibitor, and N-(3-(aminomethyl) benzyl acetamide) ethanimidamide dihydrochloride (1400W), a highly selective iNOS inhibitor, were added to the septic plasma. The number of neutrophils adherent to endothelial cells, neutrophil rolling velocity, and the number of neutrophil aggregates were determined. Cell activation and the formation of platelet-neutrophil aggregates were assessed by flow cytometry. Separate experiments were done with isolated platelets using platelet aggregometry. l-Arginine significantly decreased sepsis-related neutrophil adhesion and aggregation and increased rolling velocity. The addition of LNMMA to LA and cell suspensions reversed the effects of LA on these parameters, whereas the addition of 1400W had no effect on LA-related changes. Platelet-neutrophil aggregation, platelet aggregation, platelet activation, and neutrophil activation induced by septic plasma were also significantly decreased by LA. Again, the addition of LNMMA reversed the effects of LA on these parameters, whereas 1400W had no effect on LA-related changes. These data suggest that enhancement of platelet and endothelial cell eNOS activity decreases sepsis-induced neutrophil-endothelial cell interactions and may play a role in maintaining microvascular patency in septic shock.

The effect of anticoagulants and the role of thrombin on neutrophil-endothelial cell interactions in septic shock.

To examine the effects of anticoagulants and the role of thrombin on neutrophil-platelet-endothelial cell interactions in septic shock. Controlled experiments using phase-contrast microscopy to study neutrophil, platelet, and endothelial cell interactions in flowing cell suspensions under simulated physiologic conditions. University research laboratory. Adult patients with septic shock and normal volunteers. Microslides were coated with human umbilical vein endothelial cells. Neutrophils and platelets removed from control subjects were stimulated with plasma from patients in septic shock and perfused over endothelial cells. Heparin (H), argatroban (A), antithrombin III (ATIII), and recombinant human activated protein C (rhAPC) with and without thrombin were added to cells suspended in septic plasma and normal plasma. The number of neutrophils adherent to endothelial cells, neutrophil rolling velocity, and the number of neutrophils in aggregates were determined. Flow cytometric analysis of cells was used to identify cell activation and the formation of platelet-neutrophil aggregates. Heparin, A, ATIII, rhAPC all significantly decreased neutrophil adhesion and aggregation, and increased rolling velocity of neutrophils suspended in septic plasma. These results are similar to those observed with normal plasma but present greater absolute changes. Platelet-neutrophil aggregation, platelet activation, and neutrophil activation were significantly decreased by each of the anticoagulants. The addition of thrombin to cell suspensions containing anticoagulants reversed the effects of H, A, ATIII, rhAPC on neutrophil adhesion, adherence, and rolling velocity. In addition, thrombin attenuated the effects of each of these agents on platelet-neutrophil aggregation, platelet activation, and neutrophil activation. These data suggest that H, A, ATIII, and rhAPC decrease sepsis-induced neutrophil-endothelial cell interactions. The reversal of this effect by thrombin suggests that these agents alter neutrophil-endothelial interactions through their anticoagulant effects and the resulting decrease in thrombin activity.