Search

Background: The search for reliable diagnostic biomarkers of sepsis remains necessary. Assessment of global metabolic profiling using quantitative nuclear magnetic resonance (NMR)-based metabolomics offers an attractive modern methodology for fast and comprehensive determination of multiple circulating metabolites and for defining the metabolic phenotype of sepsis.Objective: To develop a novel NMR-based metabolomic approach for diagnostic evaluation of sepsis.Methods: Male Sprague-Dawley rats (weight 325-375 g) underwent cecal ligation and puncture (n = 14, septic group) or sham procedure (n = 14, control group) and 24 h later were euthanized. Lung tissue, bronchoalveolar lavage (BAL) fluid, and serum samples were obtained for (1)H NMR and high-resolution magic-angle spinning analysis. Unsupervised principal components analysis was performed on the processed spectra, and a predictive model for diagnosis of sepsis was constructed using partial least-squares discriminant analysis.Results: NMR-based metabolic profiling discriminated characteristics between control and septic rats. Characteristic metabolites changed markedly in septic rats as compared with control rats: alanine, creatine, phosphoethanolamine, and myoinositol concentrations increased in lung tissue; creatine increased and myoinositol decreased in BAL fluid; and alanine, creatine, phosphoethanolamine, and acetoacetate increased whereas formate decreased in serum. A predictive model for diagnosis of sepsis using these metabolites classified cases with sensitivity and specificity of 100%.Conclusions: NMR metabolomic analysis is a potentially useful technique for diagnosis of sepsis. The concentrations of metabolites involved in energy metabolism and in the inflammatory response change in this model of sepsis. [ABSTRACT FROM AUTHOR]

To demonstrate that increased formation of reactive oxygen (ROS) and nitrogen species (RNS) is involved in VILI-induced vascular dysfunction. Male Sprague-Dawley anesthetized rats were ventilated for 60 min using low VT ventilation [VT 9 ml/kg, positive end-expiratory pressure (PEEP) 5 cmH2O, n = 18], and high VT ventilation (VT 35 ml/kg, zero PEEP, n = 18). Arterial pressure and respiratory system mechanics were monitored. Blood samples for the determination of arterial blood gases and lactate concentration were drawn. Vascular rings from the thoracic aortae were mounted in organ baths for isometric tension recording. We studied endothelium-dependent relaxation in norepinephrine-precontracted rings (acetylcholine, 10 nM–10 μM) and contraction induced by norepinephrine (1 nM–10 μM) in resting vessels. Vascular rings were preincubated for 30 min with Zn–Mn–SOD (100 u/ml) or tempol (10−4 M) (extracellular and intracellular superoxide scavengers, respectively) or MnTMPyP (10−5 M) (a superoxide and peroxynitrite scavenger). The presence of superoxide and nitrotyrosine in aortic rings was evaluated by immunofluorescence. High VT ventilation induced hypotension, systemic acidosis, hypoxemia and hyperlactatemia, as well as impairment in acetylcholine and norepinephrine-induced responses in vitro. Responses to acetylcholine were improved by tempol ( P = 0.004) and completely corrected ( P < 0.001) by MnTMPyP. Responses to norepinephrine were also improved by treatment with tempol ( P < 0.001) and MnTMPyP ( P < 0.001). However, Zn–Mn–SOD did not improve acetylcholine- or norepinephrine-induced responses. Immunostaining for both superoxide and nitrotyrosine was increased in aortic rings from the high VT group. Our data support a role for intracellular ROS and peroxynitrite in the high VT ventilation-induced vascular dysfunction. [ABSTRACT FROM AUTHOR]

To describe the time course of the changes in pulmonary and vascular function, and systemic inflammation induced by injurious mechanical ventilation. Experimental study in an animal model of ventilator-induced lung injury. Animal research laboratory. Anesthetized male adult Sprague-Dawley rats were ventilated with VT 9 ml/kg and PEEP 5 cm H2O, or VT 35 ml/kg and zero PEEP for 1 h, and were killed. Other rats received ventilation for 1 h with high VT, to observe survival ( n = 36), or to be monitored and killed at different points in time (24, 72 and 168 h; n = 7 in each group). Blood samples for measuring biochemical parameters were obtained. Post-mortem, a bronchoalveolar lavage (BAL) was performed, the aorta and pulmonary microvessels were isolated to examine ex-vivo vascular responses and pulmonary slices were examined (light microscopy). Mortality in rats ventilated with high VT was 19 of 36 (54%). Mechanical ventilation was associated with hypotension, hypoxaemia and membrane hyaline formation. AST, ALT, IL-6, MIP-2 serum and BAL fluid concentrations, as well as VEGF BAL fluid concentration, were increased in rats ventilated with high VT. Lung injury score was elevated. Aortic vascular responses to acetylcholine and norepinephrine, and microvascular responses to acetylcholine, were impaired. These changes resolved by 24–72 h. Injurious ventilation is associated with respiratory and vascular dysfunction, accompanied by pulmonary and systemic inflammation. The survival rate was about 50%. In survivors, most induced changes completely normalized by 24–72 h after the insult. [ABSTRACT FROM AUTHOR]

To test the hypothesis that aging increases the susceptibility to organ dysfunction and systemic inflammation induced by injurious mechanical ventilation. Experimental study in an animal model of ventilator-induced lung injury in the animal research laboratory in a university hospital. Young (3–4 months old) and old (22–24 months old) anesthetized Wistar rats were ventilated for 60 min with a protective lung strategy (VT = 9 ml/kg and PEEP = 5 cm H2O, control) or with an injurious strategy (VT = 35 ml/kg and PEEP = 0 cm H2O, overventilated; n = 6 for each group). Mean arterial pressure and airway pressures (PAW) were monitored. Arterial blood gases and serum AST, ALT, lactate, and IL-6 were measured. Vascular rings from the thoracic aorta were mounted in organ baths for isometric tension recording. We studied relaxations induced by acetylcholine (10 nM–10 μM) in norepinehrine-precontracted rings, and contractions induced by norepinephrine (1 nM–10 μM) in resting vessels. Lungs were examined by light microscopy. Injurious ventilation in young rats was associated with hypoxemia, lactic metabolic acidosis, increased serum AST, hypotension, impairment in norepinephrine and acetylcholine-induced vascular responses ex vivo and hyaline membrane formation. The high-VT induced hypotension, increase in mean PAW, AST, and IL-6, and the impairment in acetylcholine-induced responses were significantly more marked in aged than in young rats. Elderly rats showed increased susceptibility to injurious mechanical ventilation-induced pulmonary injury, vascular dysfunction, and systemic inflammation. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented regarding the effect of pandemic 2009 influenza A (H1N1) virus infection on the histopathological changes in kidney.