RESUMEN
BACKGROUND: Spinal cord injuries (SCI) can lead to severe bladder pathologies associated with inflammation, fibrosis, and increased susceptibility to urinary tract infections. We sought to characterize the complex pathways of remodeling, inflammation, and infection in the urinary bladder at the level of the transcriptome in a rat model of SCI, using pathways analysis bioinformatics. METHODOLOGY/PRINCIPAL FINDINGS: Experimental data were obtained from the study of Nagatomi et al. (Biochem Biophys Res Commun 334: 1159). In this study, bladders from rats subjected to surgical SCI were obtained at 3, 7 or 25 days post-surgery, and Affymetrix GeneChip Rat Genome U34A arrays were used for cRNA hybridizations. In the present study, Ingenuity Pathways Analysis (Ingenuity Systems, www.ingenuity.com) of differentially expressed genes was performed. Analysis of focus genes in networks, functional analysis, and canonical pathway analysis reinforced our previous findings related to the presence of up-regulated genes involved in tissue remodeling, such as lysyl oxidase, tropoelastin, TGF-beta1, and IGF-1. This analysis also highlighted a central role for inflammation and infection, evidenced by networks containing genes such as CD74, S100A9, and THY1. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that tissue remodeling, infection, inflammation, and tissue damage/dysfunction all play a role in the urinary bladder, in the complex response to SCI.
Asunto(s)
Regulación de la Expresión Génica , Infecciones/complicaciones , Infecciones/fisiopatología , Inflamación , Traumatismos de la Médula Espinal/complicaciones , Traumatismos de la Médula Espinal/fisiopatología , Vejiga Urinaria/patología , Animales , Biología Computacional/métodos , Femenino , Fibrosis/patología , Análisis de Secuencia por Matrices de Oligonucleótidos , Ratas , Ratas Sprague-Dawley , Factores de TiempoRESUMEN
Trauma and hemorrhagic shock (HS) elicit severe physiological disturbances that predispose the victims to subsequent organ dysfunction and death. The general lack of effective therapeutic options for these patients is mainly due to the complex interplay of interacting inflammatory and physiological elements working at multiple levels. Systems biology has emerged as a new paradigm that allows the study of large portions of physiological networks simultaneously. Seeking a better understanding of the interplay among known inflammatory pathways, we constructed a mathematical model encompassing the dynamics of the acute inflammatory response that incorporates the intertwined effects of inflammation and global tissue damage. The model was calibrated using data from C57Bl/6 mice subjected to endotoxemia, sham operation (i.e., surgical trauma induced by cannulation [ST]) or ST + HS+ resuscitation (ST-HS-R). An in silico simulation, made at whole-organism level, suggested that similar pathways of different magnitudes were operant as the degree of total body damage increased. We sought to validate this hypothesis by subjecting mice to HS and comparing the models predictions to circulating markers of inflammation and tissue injury as well as the global transcriptomic response of the liver. C57Bl/6 mice were subjected to ST or ST-HS (without resuscitation). Liver gene expression was assessed using an Affymetrix DNA microarray (GeneChip Mouse Expression Set 430A, Affymetrix, Santa Clara, CA), which contains 22,621 probe sets and effectively interrogates 12,341 mouse genes. The microarray data sets were subjected to hierarchical clustering and pathway analysis. In agreement with model predictions, circulating levels of inflammation/tissue injury markers and the microarray analysis both demonstrated that ST alone accounts for a substantial proportion of the observed phenotypic and genetic/molecular changes versus untreated animals. The addition of HS further increased the magnitude of gene expression, but relatively few additional genes were recruited. Mathematical simulations and DNA microarrays, both systems biology tools, may provide valuable insight into the complex global physiological interactions that occur in response to trauma and hemorrhagic shock.
Asunto(s)
Hígado/metabolismo , Choque Hemorrágico/metabolismo , Transcripción Genética , Heridas y Lesiones/metabolismo , Animales , Simulación por Computador , Modelos Animales de Enfermedad , Genómica , Inflamación , Interleucina-10/sangre , Interleucina-6/sangre , Ratones , Ratones Endogámicos C57BL , Modelos Teóricos , Óxido Nítrico/metabolismo , Análisis de Secuencia por Matrices de OligonucleótidosRESUMEN
Hemorrhagic shock (HS) followed by resuscitation (HS-R) is characterized by profound physiological changes. Even if the patient survives the initial blood loss, these poorly understood changes can lead to morbidity. One of the tissues most often affected is liver. We sought to recognize specific hepatic changes induced by this stressor to identify targets for therapeutic intervention. Gene array analyses using mouse liver mRNAs were used to identify candidate genes that contribute to hepatic damage. To verify the role of one of the genes identified using the arrays, mice were subjected to HS-R, and multiple parameters were analyzed. A profound increase in plasminogen activator inhibitor type 1 (PAI-1) mRNA was observed using hepatic mRNAs from C57Bl/6 mice after HS, both with and without resuscitation. Constitutive loss of PAI-1 resulted in notable tissue preservation and lower (P < .05) alanine aminotransferase (ALT) levels. Fibrin degradation products (FDPs) and interleukins 6 and 10 (IL-6 and IL-10) were unaffected by loss of PAI-1; however, enhanced urokinase activity, an elevation of active hepatocyte growth factor (HGF), an increase in unprocessed transforming growth factor-beta1 (TGF-beta1), and retention of ERK phosphorylation after HS-R were associated with improved hepatic function. In conclusion, PAI-1 protein is a negative effector of hepatic damage after HS-R through its influence on classic regulators of hepatic growth, as opposed to its role in fibrinolysis.