Antonio Ferruelo

High-tidal Volume Ventilation Aggravates Sepsis-induced Multiorgan Dysfunction In A Dexamethasone-inhibitable Manner

High-tidal volume (Vt) ventilation induces lung injury and systemic inflammation, and small doses of endotoxin have been shown to increase the susceptibility to ventilation-induced lung injury. We studied whether high-Vt ventilation increases organ injury in a model of bacterial sepsis and whether an anti-inflammatory treatment averts those changes. Anesthetized rats, monitored with an arterial catheter and a blood flow probe in the aorta, were assigned to one of four different groups: nonseptic low-Vt group (Vt = 9 mL/kg, positive end-expiratory pressure = 8 cm H2O, control group), septic low-Vt group, septic overventilated group (Vt = 35 mL/kg, positive end-expiratory pressure = 0), and septic overventiled group pretreated with dexamethasone (6 mg/kg i.p., 30 min before mechanical ventilation). Rats were ventilated for 75 min. Septic rats had undergone cecal ligation and puncture 48 h before mechanical ventilation. We measured hemodynamics, lung mechanics, blood chemistry and gas exchange, liver and heart expression of cyclooxygenase 2 (COX-2) and iNOS (reverse transcriptase-polymerase chain reaction), and lung histopathology. Septic rats showed metabolic acidosis, hiperlactatemia, lung and liver injury, increased liver and heart COX-2, and liver iNOS expression. High-Vt ventilation of septic rats was associated with more marked liver injury and heart COX-2 upregulation, as well as lung inflammation and dysfunction (impaired oxygenation, increased bronchoalveolar lavage fluid protein and IL-6 concentration, decreased thoracic system compliance) and systemic hypotension. All inflammatory changes, as well as pulmonary and vascular dysfunctions, were abrogated by dexamethasone. High-Vt ventilation in bacterial sepsis upregulates the inflammatory response and aggravates the sepsis-induced cardiovascular, pulmonary, and liver dysfunction. Dexamethasone averts mechanical ventilation-induced changes under conditions of bacterial sepsis.

Genetic predisposition to acute kidney injury induced by severe sepsis

PURPOSE The aim of this study was to demonstrate that candidate gene polymorphisms are associated with an increased risk of acute kidney injury (AKI). MATERIALS AND METHODS Patients admitted to the intensive care unit with the diagnosis of severe sepsis and an expected intensive care unit length of stay more than 48 hours were included. Genetic polymorphisms studied included angiotensin-converting enzyme insertion/deletion (polymerase chain reaction); tumor necrosis factor α -376, - 308, and -238; interleukin-8 -251; vascular endothelial growth factor (VEGF) +405 and +936; and pre-B-cell colony-enhancing factor -1001 (TaqMan SNP genotyping assay, Life Technologies, Grand Island, NY). Acute kidney injury was defined as the risk, injury, and failure categories, as per the RIFLE (risk, injury, failure, loss, end-stage kidney disease) classification. RESULTS One hundred thirty-nine patients were included, 65 of whom developed AKI. In univariate analysis, the VEGF +936 CC and the pre-B-cell colony-enhancing factor -1001 GG genotypes were associated with AKI. In multivariate analysis, Simplified Acute Physiology Score II score (odds ratio [95% confidence interval], 1.06 [1.03-1.09]), chronic arterial hypertension (3.15 [1.39-7.15]), and the presence of the VEGF +936 CC genotype (3.41 [1.19-9.79]) were associated with AKI. CONCLUSION This is the first study demonstrating an association between the VEGF +936 CC genotype and the risk to develop AKI in patients with severe sepsis.

Vascular dysfunction in sepsis: effects of the peroxynitrite decomposition catalyst MnTMPyP.

The mechanisms contributing to sepsis vascular dysfunction are not well known. We tested the hypothesis that peroxynitrite scavenging ameliorates sepsis-induced macrovascular and microvascular dysfunction. Male Sprague-Dawley rats were killed 48 h after cecal ligation (n = 15) and puncture or sham procedure (n = 15). Their aortas and mesenteric vessels were mounted in organ baths for isometric tension recording. We studied contraction in resting vessels (norepinephrine 1 nM-10 &mgr;M and 10 nM-10 &mgr;M) and endothelium-dependent relaxation (acetylcholine, 10 nM-10 &mgr;M and 1 nM-10 &mgr;M) for aortas and microvessels, respectively. Vascular rings were preincubated for 30 min with the superoxide scavenger Cu-Zn-superoxide dismutase (SOD) (100 U/mL), the SOD mimetic and peroxynitrite scavenger tempol (10−4 M), the NO synthase inhibitor N-nitro-l-arginine methyl ester (10−4 M), or the peroxynitrite decomposition catalyst manganese tetrakis(4-N-methylpyridyl)porphyrin (MnTMPyP) (10−5 M). Fluorescence to 3-nitrotyrosine, oxidized dihydroethidium, and NOS2 was assessed in vascular tissue. Vascular NOS2, endothelial nitric oxide synthase (NOS1), NADPH-oxidase-1 (NOX-1), and SOD expression was analyzed by reverse transcription-polymerase chain reaction. Sepsis induced (i) in macrovessels, impairment of norepinephrine-induced contractions; (ii) in microvessels, impairment in norepinephrine-induced contractions and acetylcholine-induced relaxations; (iii) aortic and microvascular tissue increased reactivity to 3-nitrotyrosine, oxidized dihydroethidium, NOS2, and increased expression of NOS2, as well as increased expression of NOX-1 in microvascular tissue. Contractile responses in aortic and microvascular rings improved by ex vivo treatment with MnTMPyP and tempol, whereas vascular relaxation in microvessels improved only with MnTMPyP. Peroxynitrite scavenging protects from vascular dysfunction in sepsis.

Genetic predisposition to acute respiratory distress syndrome in patients with severe sepsis

ABSTRACT Objective: The objective of this study was to analyze the association between candidate gene polymorphisms and susceptibility to acute respiratory distress syndrome (ARDS) in patients with severe sepsis. Methods: Patients older than 18 years admitted to the intensive care unit (ICU) with the diagnosis of severe sepsis were prospectively included. A blood sample was drawn on the first day of ICU admission, and DNA was extracted. We genotyped the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) gene (polymerase chain reaction) and the following single-nucleotide polymorphisms (TaqMan SNP genotyping assay): tumor necrosis factor &agr; -376 G/A, -308 G/A, and -238 G/A; interleukin 8 -251 T/A; pre–B cell colony-enhancing factor -1001 G/T; and vascular endothelial growth factor +405 C/G and +936 C/T. Polymorphisms were selected based on reports on their association with ARDS. Variables associated in univariate analysis (P < 0.1) with the diagnosis of ARDS were included in a multiple logistic regression analysis. Results: We studied 149 patients, of whom 35 presented ARDS. Variables included in the maximal multivariate model were male sex, chronic alcoholism, use of ACE inhibitors or angiotensin-receptor blockers, Simplified Acute Physiology Score II score, serum glucose concentration at ICU admission, and the presence of the allele D of the ACE gene. After adjustment for those variables, the presence of the allele D of the ACE gene (odds ratio, 4.75; 95% confidence interval, 1.02–22.20; P = 0.048) was significantly associated with the diagnosis of ARDS. Conclusion: The presence of the allele D of the ACE gene is associated with ARDS in patients with severe sepsis.

Characteristics of microRNAs and their potential relevance for the diagnosis and therapy of the acute respiratory distress syndrome: from bench to bedside

Acute respiratory distress syndrome (ARDS) is a complex disease associated with high morbidity and mortality. Biomarkers and specific pharmacologic treatment of the syndrome are lacking. MicroRNAs (miRNAs) are small (∼ 19-22 nucleotides) noncoding RNA molecules whose function is the regulation of gene expression. Their uncommon biochemical characteristics (eg, their resistance to degradation because of extreme temperature and pH fluctuations, freeze-thaw cycles, long storage times in frozen conditions, and RNAse digestion) and their presence in a wide range of different biological fluids and the relatively low number of individual miRNAs make these molecules good biomarkers in different clinical conditions. In addition, miRNAs are suitable therapeutic targets as their expression can be modulated by different available strategies. The aim of the present review is to offer clinicians a global perspective of miRNA, covering their structure and nomenclature, biogenesis, effects on gene expression, regulation of expression, and features as disease biomarkers and therapeutic targets, with special attention to ARDS. Because of the early stage of research on miRNAs applied to ARDS, attention has been focused on how knowledge sourced from basic and translational research could inspire future clinical studies.

Determinantes genéticos del riesgo y pronóstico del daño renal agudo: una revisión sistemática

INTRODUCTION Acute renal damage (ARD) is a frequent syndrome in hospitalized patients. It is well accepted that ARD susceptibility and outcome are related to environmental risk factors and to the patient premorbid status. Recently, host factors have also been recognized as important in ARD predisposition and evolution. OBJECTIVE To analyze genetic influences related to the risk and severity of ARD. DATA SOURCE MEDLINE search. SELECTION OF STUDIES articles published in English or Spanish between 1/1/1995 and 31/5/2011, analyzing the association between genic polymorphisms and (a) ARD susceptibility in patients versus healthy controls or within groups of patients; or (b) ARD severity. EXCLUSION CRITERIA studies published only in abstract form, case reports or including patients less than 16 years of age, on chronic dialysis or having received a renal transplant. DATA EXTRACTION at least one investigator analyzed each manuscript and collected the information using a predefined form. RESULTS We identified 12 relevant studies that included 4835 patients. Eleven genes showed polymorphisms related to ARD susceptibility or severity. They were related to cardiovascular regulation (ACE I/D, eNOS, FNMT and COMT), inflammatory response (TNFα, IL10, IL6, HIP-1α, EPO), oxidative stress (NAPH oxidase) and lipid metabolism (APO E). Only APO E, ACE and AT1 receptor have been analyzed in more than one study. CONCLUSION ARD susceptibility and severity is influenced by genetic factors, which are multiple and involve different physiopathological mechanisms.

Antioxidant effect of human adult adipose-derived stromal stem cells in alveolar epithelial cells undergoing stretch

INTRODUCTION Alveolar epithelial cells undergo stretching during mechanical ventilation. Stretch can modify the oxidative balance in the alveolar epithelium. The aim of the present study was to evaluate the antioxidant role of human adult adipose tissue-derived stromal cells (hADSCs) when human alveolar epithelial cells were subjected to injurious cyclic overstretching. METHODS A549 cells were subjected to biaxial stretch (0-15% change in surface area for 24h, 0.2Hz) with and without hADSCs. At the end of the experiments, oxidative stress was measured as superoxide generation using positive nuclear dihydroethidium (DHE) staining, superoxide dismutase (SOD) activity in cell lysates, 8-isoprostane concentrations in supernatant, and 3-nitrotyrosine by indirect immunofluorescence in fixed cells. RESULTS Cyclically stretching of AECs induced a significant decrease in SOD activity, and an increase in 8-isoprostane concentrations, DHE staining and 3-nitrotyrosine staining compared with non-stretched cells. Treatment with hADSCs significantly attenuated stretch-induced changes in SOD activity, 8-isoprostane concentrations, DHE and 3-nitrotyrosine staining. CONCLUSION These data suggest that hADSCs have an anti-oxidative effect in human alveolar epithelial cells undergoing cyclic stretch.

0854. Metabolomic changes by mass spectrometry in lung tissue from septic rats with mechanical ventilation-induced lung injury

Methods Rats received cecal-ligation and puncture (CLP) or sham operation, and 24 h later underwent mechanical ventilation for 2.5 h with either VT=9 ml/kg, positive end-expiratory pressure (PEEP)=0 cm H2O (n=9 and n=12, without and with CLP, respectively); or VT=25 ml/kg, PEEP=5 cm H2O (n=13 and n=12, without and with CLP, respectively). Lung tissue samples were obtained and analyzed by nontargeted global fingerprinting approach for lung tissue analysis, applying multiple complementary analytical techniques, including liquid cromatography-mass spectrometry (MS), gas cromatography-MS, and capillary electrophoresis-MS. We followed the Principles of Laboratory Animal Care (2010/63/UE 22-09, RD 53/2013 BOE 1-02, ley 32/2007 BOE 7-11).