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
-
These studies evaluated the effects treatment with glucan phosphate, a soluble polysaccharide immunomodulator, on the inflammatory response induced by burn injury and on resistance to Pseudomonas aeruginosa burn wound infection. Mice were exposed to 35% total body surface area burns and were resuscitated with lactated Ringer's (LR) solution alone or LR supplemented with glucan phosphate (40 mg/kg). Glucan phosphate treatment attenuated burn-induced expression of interleukin (IL)-1beta, IL-6, and IL-10 mRNAs in spleen, lung, and heart. ⋯ Glucan phosphate treatment significantly improved survival in mice exposed to P. aeruginosa burn wound infection. The improved survival correlated with lower bacterial burden in the burn wound, attenuated production of proinflammatory cytokines, and enhanced production of Th1 cytokines. These studies show that glucan phosphate treatment attenuates burn-induced inflammation and increases resistance to P. aeruginosa burn wound infection in an experimental model of burn injury.
-
Decreased lymphocyte proliferation, lymphopenia, immunodepression, and opportunistic infections are common after major trauma. Early alimentation in these patients corrects lymphopenia, enhances immunity, and reduces the incidence of infections, but the underlying mechanisms are poorly understood. Tryptophan is essential for the production and function of rapidly proliferating cells such as lymphocytes. ⋯ Although patients with poor outcomes (i.e., BS, ARDS, MOF, and death) had significantly lower tryptophan levels and greater lymphopenia on several days after injury, the sample size was too small to draw any definitive conclusions. These data indicate that decreased plasma tryptophan levels and lymphopenia typically occur after major trauma. A concomitant increase in kynurenine suggests that the observed tryptophan deficiency is caused, in part, by IDO-mediated tryptophan degradation.
-
Na(+)/H(+) exchange (NHE) is involved in the myocardial injury that occurs during ischemia and reperfusion. The goal of the present study was to investigate the role of NHE in hypovolemic circulatory shock by using a potent NHE-1 selective inhibitor BIIB513. Acute rapid hemorrhage was induced in 14 pigs by bleeding (30 mL/kg over 30 min). ⋯ NHE blockade also attenuated the metabolic acidosis, improved tissue oxygen delivery, and improved cardiac function from resuscitation. The circulating levels of creatine phosphokinase (CPK) and cardiac troponin-I were significantly lower in the BIIB513 treatment group. These results suggest that NHE activation plays an important pathophysiological role in hypovolemic circulatory shock, and NHE-1 blockade is a powerful intervention to improve cardiovascular outcomes of resuscitation from prolonged hypovolemic circulatory shock.
-
Gram-negative bacterial infection predisposes to the development of shock and acute lung injury with multiple organ dysfunction in the critically ill. Although overexpression of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta, IL-6, IL-8, and other mediators is causally implicated in the pathogenesis of shock and lung injury, the underlying mechanisms following cellular exposure to gram-negative endotoxin remain unclear. De novo generation of reactive oxygen species (ROS) by monocytes/macrophages in particular has been proposed as a pivotal regulatory mechanism by which enhanced transactivation of redox-sensitive genes culminates in augmented cytokine expression within the lower respiratory tract. ⋯ We found that M40403 potently suppressed the production of superoxide, TNF-alpha, and IL-6 in LPS-stimulated alveolar macrophages, suggesting a key role for superoxide in endotoxin-induced cytokine production in the distal air spaces. In addition, M40403 decreased E. coli LPS-induced activation of NF-kappaB, and this effect was associated with modest suppression of cytoplasmic IkappaB-alpha degradation. Together, these results suggest that removal of superoxide by M40403 inhibits endotoxin-induced production of TNF-alpha and IL-6 in alveolar macrophages by a mechanism involving suppression of redox-sensitive NF-kappaB transactivation or signaling.
-
Thermal injury induces immune dysfunction and alters numerous physiological parameters. Studies have proposed that genetics influence the outcome after traumatic injury and/or sepsis, however, the contribution of genetics to the immune-inflammatory response postburn has not been investigated. In this study, mice of three distinct genetic backgrounds (C57BL/6NCrlBR, BALB/cAnNCrlBR, and 129S6/SvEvTac) were subjected to thermal injury or a sham procedure, and 3 days later, blood and splenic immune cells (splenocytes and macrophages) were isolated for analysis. ⋯ However, significant postburn weight loss was observed in the BALB/cNCrlBR and 129S6/SvEvTac strains, but not in the C57BL/6NCrlBR strain. In summary, these findings support the concept that the immune-inflammatory response postburn is influenced by genetic make-up. Further elucidation of the influence of genetics under such conditions is likely to contribute to the improvement in existing, and development of new, therapeutic regimes for burn patients.