OBJECTIVETo investigate the effects of high-volume hemofiltration (HVHF) on hemodynamics, vasoactive factors, and vascular endothelial permeability in children with septic shock by a comparative analysis.

METHODSThirty-six children who were diagnosed with septic shock between January 2013 and September 2014 were randomly divided into control and observation groups (n=18 each). Children in the control group were treated with the standard-volume hemofiltration (SVHF), while children in the observation group were treated with HVHF. The hemodynamic indices and levels of vasoactive factors including 6-keto-prostaglandin F1α (6-keto-PGF1α), thromboxane B2 (TXB2), soluble E-selectin (sE-selectin), and endothelium-derived relaxing factor (EDRF) were determined before and after treatment. In addition, the effects of ultrafiltrate on endothelial cell permeability were assessed.

RESULTSCompared with the control group, the observation group had significantly higher mean arterial pressure, significantly higher blood oxygen saturation, and a significantly lower heart rate after treatment (P<0.05). The levels of TXB2 and sE-selectin were significantly lower in the observation group than in the control group (P<0.05), while the levels of 6-keto-PGF1α and EDRF were significantly higher in the observation group than in the control group (P<0.05). Compared with the control group, the ultrafiltrate significantly attenuated the transepithelial electrical resistance in the observation group (P<0.05).

CONCLUSIONSCompared with SVHF, HVHF is a more effective approach for improving the hemodynamics and levels of vasoactive factors and reducing the vascular endothelial permeability in children with septic shock.

Capillary Permeability ; Child ; Child, Preschool ; Epoprostenol ; physiology ; Female ; Hemodynamics ; Hemofiltration ; Humans ; Infant ; Male ; Shock, Septic ; physiopathology ; Thromboxane A2 ; physiology

OBJECTIVETo evaluate the role of endogenous vasoactive substances in hyperdynamic circulation after orthotopic liver transplantation (OLT) in cirrhotic rats.

METHODSMale SD rats were randomly divided into 4 groups: normal controls (NL, n = 10), rats with intrahepatic portal hypertension (IHPH, n = 10), normal rats with OLT (NL-OLT, n = 9), and IHPH rats with OLT (IHPH-OLT, n = 16). IHPH-OLT rats were divided into 2 subgroups: Group A (3 days after OLT, n = 9) and Group B (7 days after OLT, n = 7). IHPH was induced by injection of CCI(4) and OLT was performed using cuffs for the anastomosis of suprahepatic inferior vena cava, infrahepatic vena cava and portal vein. Radioactive microsphere method was used for hemodynamic study. The concentrations of plasma glucagon (Glu), nitric oxide (NO), prostaglandin (PGI(2)), thromboxaneA(2) (TXA(2)) and endothelin (ET) were measured by radioimmunoassay.

RESULTSNo significant difference in hemodynamic changes was observed between NL-OLT and NL rats, except for mean arterial blood pressure. No significant changes in NO and PGI(2) were seen between NL-OLT and NL rats. Glu, ET and TXA(2) were significantly elevated in NL-OLT rats compared with NL rats (P < 0.05). Characteristics of systemic and splanchnic hyperdynamic circulatory states were observed in IHPH, IHPH-OLT A, IHPH-OLT B rats. Both the magnitude of hyperhemodynamics and increasing concentrations of Glu and NO occurred in the order of IHPH > IHPH-OLT A > IHPH-OLT B rats. The level of plasma PGI(2) in IHPH rats was significantly elevated compared with NL rats, while PGI(2) in IHPH-OLT A and B rats was found to be lower than in IHPH rats (P < 0.05). There was no obvious difference in PGI(2) between IHPH-OLT B and NL rats. Vasoconstrictors including ET and TXA(2) were found elevated in IHPH-OLT rats.

CONCLUSIONSOLT does not induce postoperative hyperhemodynamics per se. Vasodilators including NO and Glu, especially NO, play an important role in the hyperhemodynamics of IHPH and IHPH-OLT rats. The results of the present study demonstrate that the persistence of systemic and splanchnic hyperkinetic circulation in the early stages after OLT may result from those non-eliminated factors that caused hyperhemodynamics in liver cirrhosis patients with portal hypertension before OLT.

Animals ; Endothelins ; blood ; physiology ; Epoprostenol ; blood ; physiology ; Glucagon ; blood ; physiology ; Hemodynamics ; Liver Cirrhosis, Experimental ; physiopathology ; Liver Transplantation ; Male ; Nitric Oxide ; blood ; physiology ; Rats ; Rats, Sprague-Dawley ; Thromboxane A2 ; blood ; physiology

The present study was carried out to examine the mechanisms of the synergistic interaction of PAF and A23187 mediated platelet aggregation. We found that platelet aggregation mediated by subthreshold concentrations of PAF (5 nM) and A23187 (1 micrometer) was inhibited by PAF receptor blocker (WEB 2086, IC50=0.65 micrometer) and calcium channel blockers, diltiazem (IC50=13 micrometer) and verapamil (IC50=18 micrometer). Pretreatment of platelets with PAF and A23187 induced rise in intracellular calcium and this effect was also blocked by verapamil. While examining the role of the down stream signaling pathways, we found that platelet aggregation induced by the co-addition of PAF and A23187 was also inhibited by low concentrations of phospholipase C (PLC) inhibitor (U73122; IC50 = 10 micrometer), a cyclooxygenase inhibitor (indomethacin; IC50=0.2 micrometer) and inhibitor of TLCK, herbimycin A with IC50 value of 5 micrometer. The effect was also inhibited by a specific TXA2 receptor antagonist, SQ 29548 with very low IC50 value of 0.05 micrometer. However, the inhibitors of MAP kinase, PD98059 and protein kinase C, chelerythrine had no effect on PAF and A23187-induced platelet aggregation. These data suggest that the synergism between PAF and A23187 in platelet aggregation involves activation of thromboxane and tyrosine kinase pathways.
Blood Platelets/*drug effects ; Calcimycin/*pharmacology ; Humans ; Indomethacin/pharmacology ; Ionophores/pharmacology ; Platelet Activating Factor/metabolism/*pharmacology ; Platelet Aggregation/*physiology ; Protein-Tyrosine Kinase/antagonists & inhibitors/*physiology ; Quinones/pharmacology ; Research Support, Non-U.S. Gov't ; Thromboxane A2/*physiology ; Verapamil/pharmacology

Our recent studies have shown that co-activation of Gq and Gi proteins by 5-hydroxytryptamine (5-HT) and adrenaline show synergism in human platelet aggregation. This study was conducted to examine the mechanism(s) of synergistic interaction of 5-HT and platelet activating factor (PAF) in human platelets. We show that PAF, but not 5-HT, increased platelet aggregation in a concentration-dependent manner. However, low concentrations of 5-HT (2 microM) potentiated platelet aggregation induced by subthreshold concentration of PAF (40 nM) indicating a synergistic interaction between the two agonists and this synergism was blocked by receptor antagonists to either 5-HT or PAF. 5-HT also potentiated the effect of PAF on thromboxane A2 (TXA2) formation and phosphorylation of extracellularly regulated mitogen-activated protein kinases (ERK1/2). The synergism of 5-HT and PAF in platelet aggregation was inhibited by calcium (Ca2+) channel blockers, verapamil and diltiazem, phospholipase C (PLC) inhibitor, U73122, cyclooxygenase (COX) inhibitor, indomethacin, and MEK inhibitor, PD98059. These data suggest that synergistic effect of 5-HT and PAF on human platelet aggregation involves activation of PLC/Ca2+, COX and MAP kinase pathways.
Diltiazem/pharmacology ; Dose-Response Relationship, Drug ; Drug Synergism ; Estrenes/pharmacology ; Flavones/pharmacology ; Human ; In Vitro ; Indomethacin/pharmacology ; Kinetics ; Mitogen-Activated Protein Kinases/metabolism ; Phosphorylation/drug effects ; Platelet Activating Factor/*pharmacology ; Platelet Activation/drug effects ; Platelet Aggregation/*drug effects/physiology ; Pyrrolidinones/pharmacology ; Serotonin/*pharmacology ; Thromboxane A2/biosynthesis ; Verapamil/pharmacology

Our recent studies have shown that co-activation of Gq and Gi proteins by 5-hydroxytryptamine (5-HT) and adrenaline show synergism in human platelet aggregation. This study was conducted to examine the mechanism(s) of synergistic interaction of 5-HT and platelet activating factor (PAF) in human platelets. We show that PAF, but not 5-HT, increased platelet aggregation in a concentration-dependent manner. However, low concentrations of 5-HT (2 microM) potentiated platelet aggregation induced by subthreshold concentration of PAF (40 nM) indicating a synergistic interaction between the two agonists and this synergism was blocked by receptor antagonists to either 5-HT or PAF. 5-HT also potentiated the effect of PAF on thromboxane A2 (TXA2) formation and phosphorylation of extracellularly regulated mitogen-activated protein kinases (ERK1/2). The synergism of 5-HT and PAF in platelet aggregation was inhibited by calcium (Ca2+) channel blockers, verapamil and diltiazem, phospholipase C (PLC) inhibitor, U73122, cyclooxygenase (COX) inhibitor, indomethacin, and MEK inhibitor, PD98059. These data suggest that synergistic effect of 5-HT and PAF on human platelet aggregation involves activation of PLC/Ca2+, COX and MAP kinase pathways.
Diltiazem/pharmacology ; Dose-Response Relationship, Drug ; Drug Synergism ; Estrenes/pharmacology ; Flavones/pharmacology ; Human ; In Vitro ; Indomethacin/pharmacology ; Kinetics ; Mitogen-Activated Protein Kinases/metabolism ; Phosphorylation/drug effects ; Platelet Activating Factor/*pharmacology ; Platelet Activation/drug effects ; Platelet Aggregation/*drug effects/physiology ; Pyrrolidinones/pharmacology ; Serotonin/*pharmacology ; Thromboxane A2/biosynthesis ; Verapamil/pharmacology