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
-
Human C1 inhibitor (C1INH) prevents endotoxin shock via a direct interaction with Gram-negative bacterial lipopolysaccharide (LPS) and improves survival in animal models of sepsis. In this report, we further characterize the interaction of C1INH with LPS and whole live bacteria. We investigate C1INH interactions with LPS from five different strains of Gram-negative enteric bacteria known to participate in the pathogenesis of human sepsis. ⋯ The binding of both native and reactive center-cleaved, inactive C1INH results in inhibition of LPS-induced proinflammatory cytokine production. Furthermore, we demonstrate the ability of C1INH to bind at the surface of only a restricted number of whole live Gram-negative bacteria as well as mutant bacteria expressing a truncated LPS lacking the O-antigen. These data reveal the interaction of C1INH with a wide range of enteric bacterial LPS and strongly suggest that the interaction between C1INH and the surface of Gram-negative microorganisms is determined by the length of the polysaccharide chain of the endotoxin molecule.
-
Randomized Controlled Trial
Continuous enteral and parenteral feeding each reduces heart rate variability but differentially influences monocyte gene expression in humans.
Enteral (EN) or parenteral (PN) nutrition is used to support critically ill patients until oral feeding resumes. Enteral nutrition is assumed preferable to PN, but the differential influence on immune function is not well defined. Autonomic nervous activity is known to influence innate immune responses, and we hypothesized that EN and PN could influence both autonomic signaling and gene activation in peripheral blood monocytes (PBMs). ⋯ However, PN feeding had a much greater influence on PBM gene expression compared with baseline than EN, including genes important to innate immunity. Continuous EN and PN are both associated with decreasing vagal tone over time, yet contribute differently to PBM gene expression, in humans. These preliminary findings support assumptions that PN imposes a systemic inflammatory risk but also imply that continuous feeding, independent of route, may impart additional risk through different mechanisms.
-
Malic acid, in the form of its anion malate, is a key intermediate in the major biochemical energy-producing cycle known as the citric acid or Krebs cycle. In this study, the authors investigated the protective effect of a novel crystalloid solution of Ringer's malate following fluid resuscitation of hemorrhagic shock using a rat model. Under general anesthesia, Sprague-Dawley male rats were subjected to 60 min of hemorrhagic shock (40 mmHg for 60 min) followed by crystalloid resuscitation. ⋯ Histopathology indicated that Ringer's malate can protect against the multiple organ injury caused by hemorrhagic shock in rats. Ringer's malate prevented circulatory failure and alleviated multiple organ dysfunction syndrome in animals with hemorrhagic shock. The study suggests that Ringer's malate solution could be a potential novel therapeutic agent for fluid resuscitation.
-
Apocynin (Apo) suppresses the generation of reactive oxygen species that are implicated in lipopolysaccharide (LPS)-induced lung injury (LPSLI). We thus hypothesized that Apo may attenuate LPSLI. In addition, we explored the cellular and molecular mechanisms of Apo treatment in LPSLI. ⋯ In addition, Apo attenuated the increase in lung weight, bronchoalveolar lavage fluid albumin content, and the histopathologic lung injury score. In conclusion, LPSLI is associated with increased inflammatory responses, apoptosis, and coagulation. The administration of Apo attenuates LPSLI through downregulation of the inflammatory responses and apoptosis.
-
The use of liposome-encapsulated hemoglobin (LHb), which is a cellular Hb, has been demonstrated to be beneficial in the treatment of hypohemoglobinemic shock. As a molecule of appropriate size (220 nm) that can carry oxygen, LHb may ameliorate cardiac dysfunction during lethal hemodilation. The purpose of this study was to determine the efficacy of LHb transfusion in relieving cardiovascular dysfunction in a rat model of lethal progressive hemodilution. ⋯ More than 80% of the rats transfused with either LHb or washed rat red blood cells survived for 8 days. Liposome-encapsulated hemoglobin transfusion suppressed hypoxia-inducible factor 1α expression in the heart, maintained low levels of heart-type fatty acid-binding protein, and attenuated sympathetic nerve activity as reflected by changes in heart rate variability and plasma levels of epinephrine and norepinephrine. The results indicate that LHb attenuates cardiac dysfunction and sympathetic overactivity during lethal hemorrhage.