Shock : molecular, cellular, and systemic pathobiological aspects and therapeutic approaches : the official journal the Shock Society, the European Shock Society, the Brazilian Shock Society, the International Federation of Shock Societies
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Syndecan 1 plays a novel role in enteral glutamine's gut-protective effects of the postischemic gut.
Syndecan 1 is the predominant heparan sulfate proteoglycan found on the surface of epithelial cells and, like glutamine, is essential in maintaining the intestinal epithelial barrier. We therefore hypothesized that loss of epithelial syndecan 1 would abrogate the gut-protective effects of enteral glutamine. Both an in vitro and in vivo model of gut ischemia-reperfusion (IR) was utilized. ⋯ In vivo, intestinal permeability, inflammation, and injury were increased after gut IR in wild-type mice and further increased in syndecan 1 KO mice. Glutamine's attenuation of IR-induced intestinal hyperpermeability, inflammation, and injury was abolished in syndecan 1 KO mice. These results suggest that syndecan 1 plays a novel role in the protective effects of enteral glutamine in the postischemic gut.
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Early detection and management of shock are important in optimizing clinical outcomes. One regional marker, sublingual capnography (SLCO2), is particularly appealing as redistribution of blood flow away from the sublingual mucosa can happen very early in the compensatory phase of hypovolemic shock. Our objective was to test the hypothesis that SLCO2 would detect early hypovolemia in a human laboratory model of hemorrhage: progressive lower body negative pressure until onset of cardiovascular collapse. ⋯ Average time to presyncope was 1,579 ± 72 s (mean ± SE). At the time of cardiovascular collapse, lower body negative pressure altered (P < 0.001) systolic blood pressure (mean ± SE: 130 ± 3 vs. 98 ± 2 mm Hg), pulse pressure (mean ± SE: 58 ± 2 vs. 33 ± 2 mm Hg), and heart rate (mean ± SE: 63 ± 3 vs. 102 ± 6 beats/min) when compared with baseline, whereas SLCO2 did not change (49.1 ± 1.0 vs. 48.6 ± 1.5 mm Hg, P = 0.624). In a model of progressive central hypovolemia in humans, we did not detect metabolic derangements in the sublingual mucosa as measured by SLCO2.
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Recombinant human soluble thrombomodulin (TM-α) was recently developed as an anticoagulant for patients with disseminated intravascular coagulation (DIC). However, the pharmacokinetics and pharmacodynamics of TM-α in DIC patients with severe renal impairment have not yet been elucidated. We investigated the pharmacokinetics and pharmacodynamics of TM-α in DIC patients with severe renal impairment. ⋯ In the pharmacokinetic simulation, however, the trough levels of TM-α increased gradually in the patients with renal impairment when the same dose of TM-α was repeatedly administered. After the administration of TM-α, the prothrombinase activities in the patients in both groups were sufficiently inhibited during the observation period. Although the pharmacokinetic values in DIC patients with severe renal impairment were only slightly different from those in DIC patients without severe renal impairment, we need to pay attention to the elevation of the trough levels of TM-α when the same dose of TM-α is repeatedly administered.
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The role and source of tumor necrosis factor-α in hemorrhage-induced priming for septic lung injury.
Tumor necrosis factor α (TNF-α) has been reported to be a key component of the functional priming, of both myeloid and nonmyeloid cells, that is thought to contribute to the lung's increased susceptibility to injury following shock. Not surprisingly, we found that mice deficient in TNF-α exhibited reduced acute lung injury (ALI) resultant from the combined insults of hemorrhagic shock and sepsis. However, we found that when we adoptively transferred neutrophils from mice expressing TNF-α to neutrophil-depleted mice that lacked TNF-α, they were not able to serve as priming stimulus for the development of ALI. ⋯ We hypothesized that alternately suppressing expression of TNF-α in lung endothelial (i.v.) or epithelial (i.t.) cells would produce a differential effect in shock-induced ALI. We found that when in vivo siRNA i.t. or i.v. against TNF-α was administered to C57/BL6 mice at 2 h after hemorrhage, 24 h before septic challenge, that systemic/i.v., but not i.t., delivery of TNF-α siRNA following hemorrhage priming significantly reduces expression of indices of ALI compared with controls. These findings suggest that an absence of local lung tissue TNF-α significantly reduces lung tissue injury following hemorrhage priming for ALI and that pulmonary endothelial and/or other possible vascular resident cells, not epithelial cells, play a greater role in mediating the TNF-α priming response in a mouse model of hemorrhage/sepsis-induced ALI.