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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Acute mitral regurgitation (MR) is present in 10% of patients presenting with cardiogenic shock. To stabilize these patients, intra-aortic balloon pumping (IABP) is recommended, but the mechanism of IABP support in these patients is unknown. This animal study was designed to describe the hemodynamic effect of intra-aortic balloon pumping during cardiogenic shock induced by acute MR. ⋯ Left ventricular function and mean coronary blood flow did not change, but diastolic coronary flow became more important as shown by the increase in diastolic fraction from 64% to 95%. (P = 0.028). Average MR dropped by 7.5% (P = 0.025). In conclusion, application of the IABP during acute MR lowers aortic impedance, resulting in less MR and more output toward the aorta without changing left ventricular function.
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Prior studies have shown that hemorrhage (Hem) can serve as a priming stimulus for acute lung injury (ALI) triggered by subsequent septic challenge (cecal ligation and puncture, CLP). Furthermore, we have reported that in vivo antibody neutralization of the chemokines, macrophage inflammatory chemokine-2 (MIP-2) and keratinocyte-derived chemokine (KC), immediately after Hem appears to differentially effect the onset of ALI. However, although we hypothesize that this is due to divergent effects of MIP-2 and KC on Hem-induced neutrophil (PMN) priming, this has not been tested. ⋯ The results show that donor PMN from Hem/IgG but not Sham-Hem mice produce increased PMN influx (increased MPO, increased % esterase+ cells in tissue) into the lung and local tissue inflammation (increased IL-6/MIP-2, decreased IL-10) in PMN-depleted CLP recipient mice, which was attenuated in mice receiving cells from Hem/anti-MIP-2 but not Hem/anti-KC treated donors. Interestingly, although Hem/anti-MIP-2 donor PMN produced comparable effects on blood IL-6/MIP-2 levels, they were ineffective in altering the change in plasma IL-10/KC levels induce by Hem. Taken together, these data demonstrate that Hem-induced priming of PMN not only mediates ALI in the mouse, but also that this process is differentially effected by MIP2 and KC, despite the fact that both signal through CXCR2.
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Comparative Study
Effects of age on mortality and antibiotic efficacy in cecal ligation and puncture.
The incidence and mortality of sepsis increase with age, consequently, 80% of the clinical mortality from sepsis occurs in patients over age 65. Despite this aged clinical population, most research models of sepsis use 6- to 16-week-old mice as patient surrogates. This age range of mice corresponds to human ages 10 to 17 years. ⋯ When compared with young mice, aged mice had higher levels of IL-6 and TNF-alpha 24 h after CLP. However, high IL-6 was predictive of mortality at any age. Mice appear to have age-dependent responses to intra-abdominal sepsis and to appropriate therapy.
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There is evidence suggesting that the ischemic gut is a major source of factors that lead to neutrophil activation, and that neutrophil activation can be reduced by hypertonic saline resuscitation. Thus, we tested whether trauma-hemorrhagic shock-induced neutrophil activation can be reduced by hypertonic saline resuscitation, as well as whether hypertonic saline reduces the ability of mesenteric lymph from shocked animals to activate neutrophils. Male Sprague-Dawley rats subjected to trauma (laparotomy), plus 90 min of shock [mean arterial pressure (MAP) MAP = 30 mmHg] or sham shock were resuscitated with Ringer's lactate or 7.5% hypertonic saline at an equivalent sodium load. ⋯ Additionally, T/HS lymph from the Ringer's lactate- but not the hypertonic saline-treated rats induced PMN L-selectin shedding. Lastly, T/HS lymph from the Ringer's lactate-treated rats induced the greatest PMN respiratory burst. These results indicate that resuscitation from T/HS with hypertonic saline is associated with less PMN activation than resuscitation with Ringer's lactate, and that factors produced or released by the postischemic intestine and carried in the mesenteric lymph contribute to neutrophil activation after an episode of T/HS.
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Comparative Study
The pattern of preformed cytokines in tissues frequently affected by blunt trauma.
The aim of this prospective study was to determine the local concentrations of inflammatory mediators in various tissue types frequently affected by trauma to estimate the role of prestored cytokine release by mechanical tissue trauma in the induction of a systemic inflammatory response syndrome. The degree of tissue damage, evaluated by its systemic release of inflammatory mediators, represents an important factor concerning the outcome of trauma patients. Clinical trials indicate that the kind of traumatized tissue influences the cytokine pattern measured in patients blood afterwards. ⋯ Due to their consistent presence at the tissue level, high systemic concentrations of IL-6 and IL-8 in patients blood, seen after pulmonary trauma, long bone fractures, or soft tissue injury, may be interpreted as an overspill of local trauma mediators. This indicates their relevance in post-traumatic monitoring. Furthermore, albumin is a suitable and necessary indicator to evaluate influences of possible blood contamination in tissue samples.