1
|
Alvarez SM, Katsamanis Karavidas M, Coyle SM, Lu SE, Macor M, Oikawa LO, Lehrer PM, Calvano SE, Lowry SF. Low-dose steroid alters in vivo endotoxin-induced systemic inflammation but does not influence autonomic dysfunction. ACTA ACUST UNITED AC 2016; 13:358-68. [DOI: 10.1177/0968051907086465] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Severe injury and infection are associated with autonomic dysfunction. Diminished heart rate variability (HRV) is also observed as a component of autonomic dysfunction and is induced by endotoxin administration to healthy subjects. It is established that low-dose glucocorticoid administration diminishes the systemic inflammatory manifestations of endotoxinemia but the influence of this anti-inflammatory intervention on overall autonomic dysfunction and HRV responses to endotoxin is unknown. This study was designed to assess the influence of a low-dose hydrocortisone infusion upon endotoxin-elicited systemic inflammatory responses including phenotypic features, cytokine production, and parameters of HRV. Of 19 subjects studied, nine received a continuous infusion of hydrocortisone (3 µg/kg/min continuously over 6 h) prior to intravenous administration of Escherichia coli endotoxin (2 ng/kg, CC-RE, Lot #2) while 10 healthy subjects received only the endotoxin after a 6-h period of saline control infusion. Serial determinations of vital signs, heart rate variability assessments, and cytokine levels were obtained over the subsequent 24 h. Prior cortisol infusion diminished the peak TNF-α ( P < 0.01) and IL-6 ( P < 0.0001) responses after endotoxin challenge, as compared to saline infusion controls and diminished the peak core temperature response to endotoxin ( P < 0.01). In contrast to the influence of cortisol on the above parameters of systemic inflammation, the significant endotoxin-induced decreases in HRV time and frequency domains were not influenced by prior hydrocortisone treatment. Hence, alterations in autonomic dysfunction occur despite hydrocortisone attenuation of other traditional systemic manifestations of endotoxinemia. The maintenance or restoration of autonomic balance is not influenced by glucocorticoid administration.
Collapse
|
2
|
Kamisoglu K, Haimovich B, Calvano SE, Coyle SM, Corbett SA, Langley RJ, Kingsmore SF, Androulakis IP. Human metabolic response to systemic inflammation: assessment of the concordance between experimental endotoxemia and clinical cases of sepsis/SIRS. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2015; 19:71. [PMID: 25887472 PMCID: PMC4383069 DOI: 10.1186/s13054-015-0783-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 02/03/2015] [Indexed: 12/28/2022]
Abstract
Introduction Two recent, independent, studies conducted novel metabolomics analyses relevant to human sepsis progression; one was a human model of endotoxin (lipopolysaccharide (LPS)) challenge (experimental endotoxemia) and the other was community acquired pneumonia and sepsis outcome diagnostic study (CAPSOD). The purpose of the present study was to assess the concordance of metabolic responses to LPS and community-acquired sepsis. Methods We tested the hypothesis that the patterns of metabolic response elicited by endotoxin would agree with those in clinical sepsis. Alterations in the plasma metabolome of the subjects challenged with LPS were compared with those of sepsis patients who had been stratified into two groups: sepsis patients with confirmed infection and non-infected patients who exhibited systemic inflammatory response syndrome (SIRS) criteria. Common metabolites between endotoxemia and both these groups were individually identified, together with their direction of change and functional classifications. Results Response to endotoxemia at the metabolome level elicited characteristics that agree well with those observed in sepsis patients despite the high degree of variability in the response of these patients. Moreover, some distinct features of SIRS have been identified. Upon stratification of sepsis patients based on 28-day survival, the direction of change in 21 of 23 metabolites was the same in endotoxemia and sepsis survival groups. Conclusions The observed concordance in plasma metabolomes of LPS-treated subjects and sepsis survivors strengthens the relevance of endotoxemia to clinical research as a physiological model of community-acquired sepsis, and gives valuable insights into the metabolic changes that constitute a homeostatic response. Furthermore, recapitulation of metabolic differences between sepsis non-survivors and survivors in LPS-treated subjects can enable further research on the development and assessment of rational clinical therapies to prevent sepsis mortality. Compared with earlier studies which focused exclusively on comparing transcriptional dynamics, the distinct metabolomic responses to systemic inflammation with or without confirmed infection, suggest that the metabolome is much better at differentiating these pathophysiologies. Finally, the metabolic changes in the recovering patients shift towards the LPS-induced response pattern strengthening the notion that the metabolic, as well as transcriptional responses, characteristic to the endotoxemia model represent necessary and “healthy” responses to infectious stimuli. Electronic supplementary material The online version of this article (doi:10.1186/s13054-015-0783-2) contains supplementary material, which is available to authorized users.
Collapse
|
3
|
Kosmides AK, Kamisoglu K, Calvano SE, Corbett SA, Androulakis IP. Metabolomic fingerprinting: challenges and opportunities. Crit Rev Biomed Eng 2014; 41:205-21. [PMID: 24579644 DOI: 10.1615/critrevbiomedeng.2013007736] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Systems biology has primarily focused on studying genomics, transcriptomics, and proteomics and their dynamic interactions. These, however, represent only the potential for a biological outcome since the ultimate phenotype at the level of the eventually produced metabolites is not taken into consideration. The emerging field of metabolomics provides complementary guidance toward an integrated approach to this problem: It allows global profiling of the metabolites of a cell, tissue, or host and presents information on the actual end points of a response. A wide range of data collection methods are currently used and allow the extraction of global or tissue-specific metabolic profiles. The great amount and complexity of data that are collected require multivariate analysis techniques, but the increasing amount of work in this field has made easy-to-use analysis programs readily available. Metabolomics has already shown great potential in drug toxicity studies, disease modeling, and diagnostics and may be integrated with genomic and proteomic data in the future to provide in-depth understanding of systems, pathways, and their functionally dynamic interactions. In this review we discuss the current state of the art of metabolomics, its applications, and future potential.
Collapse
|
4
|
Kamisoglu K, Sleight K, Nguyen TT, Calvano SE, Coyle SM, Corbett SA, Androulakis IP. Effects of coupled dose and rhythm manipulation of plasma cortisol levels on leukocyte transcriptional response to endotoxin challenge in humans. Innate Immun 2013; 20:774-84. [PMID: 24217219 DOI: 10.1177/1753425913508458] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Severe traumas are associated with hypercortisolemia due to both disruption of cortisol secretion rhythm and increase in its total concentration. Understanding the effects of altered cortisol levels and rhythms on immune function is of great clinical interest, to prevent conditions such as sepsis from complicating the recovery. This in vivo study assesses the responses of circulating leukocytes to coupled dose and rhythm manipulation of cortisol, preceding an immune challenge induced by endotoxin administration. Through continuous infusion, plasma cortisol concentration was increased to and kept constant at a level associated with major physiologic stress. In response, transcriptional programming of leukocytes was altered to display a priming response before endotoxin exposure. Enhanced expression of a number of receptors and signaling proteins, as well as lowered protein translation and mitochondrial function indicated a sensitization against potential infectious threats. Despite these changes, response to endotoxin followed very similar patterns in both cortisol and saline pre-treated groups except one cluster including probe sets associated with major players regulating inflammatory response. In sum, altered dose and rhythm of plasma cortisol levels engendered priming of circulating leukocytes when preceded an immune challenge. This transcriptional program change associated with stimulated surveillance function and suppressed energy-intensive processes, emphasized permissive actions of cortisol on immune function.
Collapse
|
5
|
Scheff JD, Calvano SE, Androulakis IP. Predicting critical transitions in a model of systemic inflammation. J Theor Biol 2013; 338:9-15. [PMID: 23973206 DOI: 10.1016/j.jtbi.2013.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 05/13/2013] [Accepted: 08/12/2013] [Indexed: 12/14/2022]
Abstract
The human body can be viewed as a dynamical system, with physiological states such as health and disease broadly representing steady states. From this perspective, and given inter- and intra-individual heterogeneity, an important task is identifying the propensity to transition from one steady state to another, which in practice can occur abruptly. Detecting impending transitions between steady states is of significant importance in many fields, and thus a variety of methods have been developed for this purpose, but lack of data has limited applications in physiology. Here, we propose a model-based approach towards identifying critical transitions in systemic inflammation based on a minimal amount of assumptions about the availability of data and the structure of the system. We derived a warning signal metric to identify forthcoming abrupt transitions occurring in a mathematical model of systemic inflammation with a gradually increasing bacterial load. Intervention to remove the inflammatory stimulus was successful in restoring homeostasis if undertaken when the warning signal was elevated rather than waiting for the state variables of the system themselves to begin moving to a new steady state. The proposed combination of data and model-based analysis for predicting physiological transitions represents a step forward towards the quantitative study of complex biological systems.
Collapse
|
6
|
Scheff JD, Mavroudis PD, Foteinou PT, Calvano SE, Androulakis IP. Modeling physiologic variability in human endotoxemia. Crit Rev Biomed Eng 2013; 40:313-22. [PMID: 23140122 DOI: 10.1615/critrevbiomedeng.v40.i4.60] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The control and management of inflammation is a key aspect of clinical care for critical illnesses such as sepsis. In an ideal reaction to injury, the inflammatory response provokes a strong enough response to heal the injury and then restores homeostasis. When inflammation becomes dysregulated, a persistent inflammatory state can lead to significant deleterious effects and clinical challenges. Thus, gaining a better biological understanding of the mechanisms driving the inflammatory response is of the utmost importance. In this review, we discuss our work with the late Stephen F. Lowry to investigate systemic inflammation through systems biology of human endotoxemia. We present our efforts in modeling the human endotoxemia response with a particular focus on physiologic variability. Through modeling, with a focus ultimately on translational applications, we obtain more fundamental understanding of relevant physiological processes. And by taking advantage of the information embedded in biological rhythms, ranging in time scale from high-frequency autonomic oscillations reflected in heart rate variability to circadian rhythms in inflammatory mediators, we gain insight into the underlying physiology.
Collapse
|
7
|
Scheff JD, Mavroudis PD, Calvano SE, Androulakis IP. Translational applications of evaluating physiologic variability in human endotoxemia. J Clin Monit Comput 2012. [PMID: 23203205 DOI: 10.1007/s10877-012-9418-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Dysregulation of the inflammatory response is a critical component of many clinically challenging disorders such as sepsis. Inflammation is a biological process designed to lead to healing and recovery, ultimately restoring homeostasis; however, the failure to fully achieve those beneficial results can leave a patient in a dangerous persistent inflammatory state. One of the primary challenges in developing novel therapies in this area is that inflammation is comprised of a complex network of interacting pathways. Here, we discuss our approaches towards addressing this problem through computational systems biology, with a particular focus on how the presence of biological rhythms and the disruption of these rhythms in inflammation may be applied in a translational context. By leveraging the information content embedded in physiologic variability, ranging in scale from oscillations in autonomic activity driving short-term heart rate variability to circadian rhythms in immunomodulatory hormones, there is significant potential to gain insight into the underlying physiology.
Collapse
|
8
|
Calvano SE, Coyle SM. Experimental human endotoxemia: a model of the systemic inflammatory response syndrome? Surg Infect (Larchmt) 2012; 13:293-9. [PMID: 23072275 DOI: 10.1089/sur.2012.155] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The normal human intravenous endotoxin model has been used for more than 50 years. It was once considered a possible model of sepsis, but, because no infection is present, it is better described as a model of systemic inflammation. We demonstrate herein that at least three of four systemic inflammatory response syndrome (SIRS) criteria are achieved with the model. METHODS Otherwise healthy human volunteers were given Escherichia coli endotoxin 2 ng/kg intravenously. Vital signs were monitored, and blood samples were collected over time for assessment of white blood cells (WBCs), cytokines, counter-regulatory hormones, and monocyte receptors. RESULTS The means of three variables (core temperature, heart rate, WBC) met the SIRS criteria. Compared with baseline, cytokines were elevated acutely, with tumor necrosis factor-alpha (TNFα) exhibiting temporal primacy over the other cytokines. Counter-regulatory hormones (cortisol, epinephrine) also were elevated acutely. Finally, the monocyte cell-surface receptors cluster of differentiation molecule (CD) 11b and TNF receptor-II were elevated and decreased, respectively. CONCLUSIONS The experimental human endotoxin model satisfies SIRS criteria and probably is best described as a model of Toll-like receptor 4 agonist-induced systemic inflammation.
Collapse
|
9
|
Mavroudis PD, Scheff JD, Calvano SE, Androulakis IP. Systems biology of circadian-immune interactions. J Innate Immun 2012; 5:153-62. [PMID: 23006670 DOI: 10.1159/000342427] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 07/12/2012] [Indexed: 01/01/2023] Open
Abstract
There is increasing evidence that the immune system is regulated by circadian rhythms. A wide range of immune parameters, such as the number of red blood cells and peripheral blood mononuclear cells as well as the level of critical immune mediators, such as cytokines, undergo daily fluctuations. Current experimental data indicate that circadian information reaches immune tissues mainly through diurnal patterns of autonomic and endocrine rhythms. In addition, immune factors such as cytokines can also influence the phase of the circadian clock, providing bidirectional flow of circadian information between the neuroendocrine and immune systems. This network of neuroendocrine-immune interactions consists of complexly integrated molecular feedback and feedforward loops that function in synchrony in order to optimize immune response. Chronic stress can disrupt this intrinsic orchestration, as several endocrine signals of chronically stressed patients present blunted rhythmic characteristics. Reprogramming of biological rhythms has recently gained much attention as a potent method to leverage homeostatic circadian controls to ultimately improve clinical outcomes. Elucidation of the intrinsic properties of such complex systems and optimization of intervention strategies require not only an accurate identification of the signaling pathways that mediate host responses, but also a system-level description and evaluation.
Collapse
|
10
|
Dick TE, Molkov YI, Nieman G, Hsieh YH, Jacono FJ, Doyle J, Scheff JD, Calvano SE, Androulakis IP, An G, Vodovotz Y. Linking Inflammation, Cardiorespiratory Variability, and Neural Control in Acute Inflammation via Computational Modeling. Front Physiol 2012; 3:222. [PMID: 22783197 PMCID: PMC3387781 DOI: 10.3389/fphys.2012.00222] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 06/03/2012] [Indexed: 01/10/2023] Open
Abstract
Acute inflammation leads to organ failure by engaging catastrophic feedback loops in which stressed tissue evokes an inflammatory response and, in turn, inflammation damages tissue. Manifestations of this maladaptive inflammatory response include cardio-respiratory dysfunction that may be reflected in reduced heart rate and ventilatory pattern variabilities. We have developed signal-processing algorithms that quantify non-linear deterministic characteristics of variability in biologic signals. Now, coalescing under the aegis of the NIH Computational Biology Program and the Society for Complexity in Acute Illness, two research teams performed iterative experiments and computational modeling on inflammation and cardio-pulmonary dysfunction in sepsis as well as on neural control of respiration and ventilatory pattern variability. These teams, with additional collaborators, have recently formed a multi-institutional, interdisciplinary consortium, whose goal is to delineate the fundamental interrelationship between the inflammatory response and physiologic variability. Multi-scale mathematical modeling and complementary physiological experiments will provide insight into autonomic neural mechanisms that may modulate the inflammatory response to sepsis and simultaneously reduce heart rate and ventilatory pattern variabilities associated with sepsis. This approach integrates computational models of neural control of breathing and cardio-respiratory coupling with models that combine inflammation, cardiovascular function, and heart rate variability. The resulting integrated model will provide mechanistic explanations for the phenomena of respiratory sinus-arrhythmia and cardio-ventilatory coupling observed under normal conditions, and the loss of these properties during sepsis. This approach holds the potential of modeling cross-scale physiological interactions to improve both basic knowledge and clinical management of acute inflammatory diseases such as sepsis and trauma.
Collapse
|
11
|
Scheff JD, Calvano SE, Lowry SF, Androulakis IP. Multiscale rhythmic influences on heart rate variability in human endotoxemia. J Crit Care 2012. [DOI: 10.1016/j.jcrc.2012.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
12
|
Mavroudis PD, Scheff JD, Calvano SE, Lowry SF, Androulakis IP. Entrainment of peripheral clock genes by cortisol. Physiol Genomics 2012; 44:607-21. [PMID: 22510707 DOI: 10.1152/physiolgenomics.00001.2012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Circadian rhythmicity in mammals is primarily driven by the suprachiasmatic nucleus (SCN), often called the central pacemaker, which converts the photic information of light and dark cycles into neuronal and hormonal signals in the periphery of the body. Cells of peripheral tissues respond to these centrally mediated cues by adjusting their molecular function to optimize organism performance. Numerous systemic cues orchestrate peripheral rhythmicity, such as feeding, body temperature, the autonomic nervous system, and hormones. We propose a semimechanistic model for the entrainment of peripheral clock genes by cortisol as a representative entrainer of peripheral cells. This model demonstrates the importance of entrainer's characteristics in terms of the synchronization and entrainment of peripheral clock genes, and predicts the loss of intercellular synchrony when cortisol moves out of its homeostatic amplitude and frequency range, as has been observed clinically in chronic stress and cancer. The model also predicts a dynamic regime of entrainment, when cortisol has a slightly decreased amplitude rhythm, where individual clock genes remain relatively synchronized among themselves but are phase shifted in relation to the entrainer. The model illustrates how the loss of communication between the SCN and peripheral tissues could result in desynchronization of peripheral clocks.
Collapse
|
13
|
Calvano SE. In memoriam: Stephen F. Lowry, MD, MBA. Crit Rev Biomed Eng 2012; 40:261-263. [PMID: 23140118 DOI: 10.1615/critrevbiomedeng.v40.i4.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
|
14
|
Scheff JD, Calvano SE, Lowry SF, Androulakis IP. Transcriptional implications of ultradian glucocorticoid secretion in homeostasis and in the acute stress response. Physiol Genomics 2011; 44:121-9. [PMID: 22128089 DOI: 10.1152/physiolgenomics.00128.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endogenous glucocorticoids are secreted by the hypothalamic-pituitary-adrenal (HPA) axis in response to a wide range of stressors. Glucocorticoids exert significant downstream effects, including the regulation of many inflammatory genes. The HPA axis functions such that glucocorticoids are released in a pulsatile manner, producing ultradian rhythms in plasma glucocorticoid levels. It is becoming increasingly evident that this ultradian pulsatility is important in maintaining proper homeostatic regulation and responsiveness to stress. This is particularly interesting from a clinical perspective given that pathological dysfunctions of the HPA axis produce altered ultradian patterns. Modeling this system facilitates the understanding of how glucocorticoid pulsatility arises, how it can be lost, and the transcriptional implications of ultradian rhythms. To approach these questions, we developed a mathematical model that integrates the cyclic production of glucocorticoids by the HPA axis and their downstream effects by integrating existing models of the HPA axis and glucocorticoid pharmacodynamics. This combined model allowed us to evaluate the implications of pulsatility in homeostasis as well as in response to acute stress. The presence of ultradian rhythms allows the system to maintain a lower response to homeostatic levels of glucocorticoids, but diminished feedback within the HPA axis leads to a loss of glucocorticoid rhythmicity. Furthermore, the loss of HPA pulsatility in homeostasis correlates with a decrease in the peak output in response to an acute stressor. These results are important in understanding how cyclic glucocorticoid secretion helps maintain the responsiveness of the HPA axis.
Collapse
|
15
|
Haimovich B, Reddell MT, Calvano JE, Calvano SE, Macor MA, Coyle SM, Lowry SF. A novel model of common Toll-like receptor 4- and injury-induced transcriptional themes in human leukocytes. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2010; 14:R177. [PMID: 20929567 PMCID: PMC3219281 DOI: 10.1186/cc9283] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 07/29/2010] [Accepted: 10/07/2010] [Indexed: 12/16/2022]
Abstract
Introduction An endotoxin challenge, sepsis, and injury/trauma, trigger significant changes in human peripheral blood leukocytes (PBL) gene expression. In this study, we have sought to test the hypothesis that the Toll-like receptor 4 (TLR4) induced transcription patterns elicited in humans exposed to in vivo endotoxin would parallel gene expression patterns observed in trauma patients with initial non-infectious injury. In addition, we sought to identify functional modules that are commonly affected by these two insults of differing magnitude and duration. Methods PBL were obtained from seven adult human subject experimental groups. The groups included a group of healthy, hospitalized volunteers (n = 15), that comprised four study groups of subjects challenged with intravenous endotoxin, without or with cortisol, and two serial samplings of trauma patients (n = 5). The PBL were analyzed for gene expression using a 8,793 probe microarray platform (Gene Chip® Focus, Affymetrix). The expression of a subset of genes was determined using qPCR. Results We describe sequential selection criteria of gene expression data that identifies 445 genes that are significantly differentially expressed (both P ≤ 0.05 and >1.2 fold-change) in PBL derived from human subjects during the peak of systemic inflammatory responses induced by in vivo endotoxin, as well as in PBL obtained from trauma patients at 1 to 12 days after admission. We identified two functional modules that are commonly represented by this analysis. The first module includes more than 50 suppressed genes that encode ribosomal proteins or translation regulators. The second module includes up-regulated genes encoding key enzymes associated with glycolysis. Finally, we show that several circadian clock genes are also suppressed in PBL of surgical ICU patients. Conclusions We identified a group of >400 genes that exhibit similar expression trends in PBL derived from either endotoxin-challenged subjects or trauma patients. The suppressed translational and circadian clock modules, and the upregulated glycolytic module, constitute a robust and long lasting PBL gene expression signature that may provide a tool for monitoring systemic inflammation and injury.
Collapse
|
16
|
Shanker BA, Coyle SM, Reddell MT, Choi CW, Calvano J, Macor MA, Calvano SE, Lowry SF. Modeling the human injury response. J Am Coll Surg 2010. [DOI: 10.1016/j.jamcollsurg.2010.06.138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
17
|
Choi CW, Coyle SM, Shanker BA, Reddell MT, Macor MA, Calvano SE, Lowry SF. The heart rate variability and entropy gaps of serious injury. J Am Coll Surg 2010. [DOI: 10.1016/j.jamcollsurg.2010.06.110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
18
|
Scheff JD, Calvano SE, Lowry SF, Androulakis IP. Modeling the influence of circadian rhythms on the acute inflammatory response. J Theor Biol 2010; 264:1068-76. [DOI: 10.1016/j.jtbi.2010.03.026] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 03/08/2010] [Accepted: 03/16/2010] [Indexed: 12/25/2022]
|
19
|
Foteinou PT, Calvano SE, Lowry SF, Androulakis IP. Multiscale model for the assessment of autonomic dysfunction in human endotoxemia. Physiol Genomics 2010; 42:5-19. [PMID: 20233835 DOI: 10.1152/physiolgenomics.00184.2009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Severe injury and infection are associated with autonomic dysfunction. The realization that a dysregulation in autonomic function may predispose a host to excessive inflammatory processes has renewed interest in understanding the role of central nervous system (CNS) in modulating systemic inflammatory processes. Assessment of heart rate variability (HRV) has been used to evaluate systemic abnormalities and as a predictor of the severity of illness. Dissecting the relevance of neuroimmunomodulation in controlling inflammatory processes requires an understanding of the multiscale interplay between CNS and the immune response. A vital enabler in that respect is the development of a systems-based approach that integrates data across multiple scales, and models the emerging host response as the outcome of interactions of critical modules. Thus, a multiscale model of human endotoxemia, as a prototype model of systemic inflammation in humans, is proposed that integrates processes across the host from the cellular to the systemic host response level. At the cellular level interacting components are associated with elementary signaling pathways that propagate extracellular signals to the transcriptional response level. Further, essential modules associated with the neuroendocrine immune crosstalk are considered. Finally, at the systemic level, phenotypic expressions such as HRV are incorporated to assess systemic decomplexification indicative of the severity of the host response. Thus, the proposed work intends to associate acquired endocrine dysfunction with diminished HRV as a critical enabler for clarifying how cellular inflammatory processes and neural-based pathways mediate the links between patterns of autonomic control (HRV) and clinical outcomes.
Collapse
|
20
|
Foteinou PT, Calvano SE, Lowry SF, Androulakis IP. In silico simulation of corticosteroids effect on an NFkB- dependent physicochemical model of systemic inflammation. PLoS One 2009; 4:e4706. [PMID: 19274080 PMCID: PMC2651450 DOI: 10.1371/journal.pone.0004706] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 12/17/2008] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND During the onset of an inflammatory response signaling pathways are activated for "translating" extracellular signals into intracellular responses converging to the activation of nuclear factor (NF)-kB, a central transcription factor in driving the inflammatory response. An inadequate control of its transcriptional activity is associated with the culmination of a hyper-inflammatory response making it a desired therapeutic target. Predicated upon the nature of the response, a systems level analysis might provide rational leads for the development of strategies that promote the resolution of the response. METHODOLOGY AND FINDINGS A physicochemical host response model is proposed to integrate biological information in the form of kinetic rules and signaling cascades with pharmacokinetic models of drug action for the modulation of the response. The unifying hypothesis is that the response is triggered by the activation of the NFkB signaling module and corticosteroids serve as a template for assessing anti-inflammatory strategies. The proposed in silico model is evaluated through its ability to predict and modulate uncontrolled responses. The pre-exposure of the system to hypercortisolemia, i.e. 6 hr before or simultaneously with the infectious challenge "reprograms" the dynamics of the host towards a balanced inflammatory response. However, if such an intervention occurs long before the inflammatory insult a symptomatic effect is observed instead of a protective relief while a steroid infusion after inducing inflammation requires much higher drug doses. CONCLUSIONS AND SIGNIFICANCE We propose a reversed engineered inflammation model that seeks to describe how the system responds to a multitude of external signals. Timing of intervention and dosage regimes appears to be key determinants for the protective or symptomatic effect of exogenous corticosteroids. Such results lie in qualitative agreement with in vivo human studies exposed both to LPS and corticosteroids under various time intervals thus improving our understanding of how interacting modules generate a behavior.
Collapse
|
21
|
Foteinou PT, Calvano SE, Lowry SF, Androulakis IP. Translational potential of systems-based models of inflammation. Clin Transl Sci 2009; 2:85-9. [PMID: 20443873 PMCID: PMC5350791 DOI: 10.1111/j.1752-8062.2008.00051.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A critical goal of translational research is to convert basic science to clinically relevant actions related to disease prevention, diagnosis, and eventually enable physicians to identify and evaluate treatment strategies. Integrated initiatives are identified as valuable in uncovering the mechanism underpinning the progression of human diseases. Tremendous opportunities have emerged in the context of systems biology that aims at the deconvolution of complex phenomena to their constituent elements and the quantification of the dynamic interactions between these components through the development of appropriate computational and mathematical models. In this review, we discuss the potential role systems-based translation research can have in the quest to better understand and modulate the inflammatory response.
Collapse
|
22
|
Kleiman DA, Calvano JE, Coyle SM, Macor MA, Calvano SE, Lowry SF. A single nucleotide polymorphism in the Mdm2 promoter and risk of sepsis. Am J Surg 2009; 197:43-8. [PMID: 18558393 DOI: 10.1016/j.amjsurg.2007.12.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 12/06/2007] [Accepted: 12/06/2007] [Indexed: 01/10/2023]
Abstract
BACKGROUND The Mdm2-SNP309(T/G) polymorphism has been shown to upregulate transcription of Mdm2 and subsequently attenuate the p53 pathway. Its role in regulating the human response to acute illness has not been reported. METHODS Patients from the surgical intensive care unit were prospectively enrolled. SNP309 genotype was determined, and a genotype-based comparison of clinical outcomes was performed. RESULTS Of the 85 enrolled patients, 41 had wild type (T/T) and 44 had mutant (32 T/G and 12 G/G) genotypes. The mutant-genotype group tended to have a longer LOS in both the surgical intensive care unit (P = .40) and the hospital (P = .08), but these trends did not reach significance. No observable genotype-based differences were noted in any other measured parameters. CONCLUSIONS The Mdm2-SNP309(G) allele may be associated with longer LOS. However, it does not appear to influence any other clinical characteristics, nor can it be used to predict clinical outcome.
Collapse
|
23
|
Foteinou PT, Calvano SE, Lowry SF, Androulakis IP. Modeling endotoxin-induced systemic inflammation using an indirect response approach. Math Biosci 2008; 217:27-42. [PMID: 18840451 DOI: 10.1016/j.mbs.2008.09.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 09/02/2008] [Accepted: 09/04/2008] [Indexed: 12/23/2022]
Abstract
A receptor mediated model of endotoxin-induced human inflammation is proposed. The activation of the innate immune system in response to the endotoxin stimulus involves the interaction between the extracellular signal and critical receptors driving downstream signal transduction cascades leading to transcriptional changes. We explore the development of an in silico model that aims at coupling extracellular signals with essential transcriptional responses through a receptor mediated indirect response model. The model consists of eight (8) variables and is evaluated in a series of biologically relevant scenarios indicative of the non-linear behavior of inflammation. Such scenarios involve a self-limited response where the inflammatory stimulus is cleared successfully; a persistent infectious response where the inflammatory instigator is not eliminated, leading to an aberrant inflammatory response, and finally, a persistent non-infectious inflammatory response that can be elicited under an overload of the pathogen-derived product; as such high dose of the inflammatory insult can disturb the dynamics of the host response leading to an unconstrained inflammatory response. Finally, the potential of the model is demonstrated by analyzing scenarios associated with endotoxin tolerance and potentiation effects.
Collapse
|
24
|
Russom A, Sethu P, Irimia D, Mindrinos MN, Calvano SE, Garcia I, Finnerty C, Tannahill C, Abouhamze A, Wilhelmy J, López MC, Baker HV, Herndon DN, Lowry SF, Maier RV, Davis RW, Moldawer LL, Tompkins RG, Toner M. Microfluidic leukocyte isolation for gene expression analysis in critically ill hospitalized patients. Clin Chem 2008; 54:891-900. [PMID: 18375483 DOI: 10.1373/clinchem.2007.099150] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Microarray technology is becoming a powerful tool for diagnostic, therapeutic, and prognostic applications. There is at present no consensus regarding the optimal technique to isolate nucleic acids from blood leukocyte populations for subsequent expression analyses. Current collection and processing techniques pose significant challenges in the clinical setting. Here, we report the clinical validation of a novel microfluidic leukocyte nucleic acid isolation technique for gene expression analysis from critically ill, hospitalized patients that can be readily used on small volumes of blood. METHODS We processed whole blood from hospitalized patients after burn injury and severe blunt trauma according to the microfluidic and standard macroscale leukocyte isolation protocol. Side-by-side comparison of RNA quantity, quality, and genome-wide expression patterns was used to clinically validate the microfluidic technique. RESULTS When the microfluidic protocol was used for processing, sufficient amounts of total RNA were obtained for genome-wide expression analysis from 0.5 mL whole blood. We found that the leukocyte expression patterns from samples processed using the 2 protocols were concordant, and there was less variability introduced as a result of harvesting method than there existed between individuals. CONCLUSIONS The novel microfluidic approach achieves leukocyte isolation in <25 min, and the quality of nucleic acids and genome expression analysis is equivalent to or surpasses that obtained from macroscale approaches. Microfluidics can significantly improve the isolation of blood leukocytes for genomic analyses in the clinical setting.
Collapse
|
25
|
|