Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aging is accompanied by an altered stress response that underlies increased susceptibility of the elderly patients to physiological stress such as infection and sepsis. In the present study, we investigated the effects of aging on mortality, hypothermia, and cytokine induction in mouse models of intra-abdominal sepsis and endotoxemia. Systemic inflammation associated with either cecal ligation/puncture (CLP) or injection with bacterial endotoxin, lipopolysaccharide (LPS), resulted in a significantly elevated mortality rate in aged (24 months) compared to young (4 months) mice. The aged mice also showed profound hypothermia during these inflammatory stresses; the severity of hypothermia at the early phase of sepsis or endotoxemia could predict the mortality of individual animals. The stress-mediated induction of interleukin-1beta, interleukin-6, and interleukin-10 (IL-1beta, IL-6, and IL-10) in the circulating blood tended to be higher with aging in both CLP and LPS models, and in particular, the induction of IL-6 was significantly augmented with aging. The serum level of IL-6 showed a strong correlation with degrees of hypothermia. In the heart and lungs, the induction of mRNA for IL-6 and IL-10 was also significantly enhanced with aging. These results clearly demonstrate an age-associated increase in mortality, hypothermia, and induction of IL-6 during endotoxemia and sepsis.
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PMID:Effects of aging on mortality, hypothermia, and cytokine induction in mice with endotoxemia or sepsis. 1465 93

Hypothermia is a thermoregulatory response to systemic inflammation that is often regarded as maladaptive to the host. However, rodents show regulated hypothermia (that is, a selection of cool ambient temperature) during systemic inflammation that correlates with enhanced survival, supporting an adaptive value to this response. The mechanisms regulating hypothermia are not fully understood, but cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukins (ILs) and interferon-gamma have been shown to induce or modulate hypothermia. A review of the literature suggests that TNF-alpha functions as an endogenous cryogen (i.e., induces hypothermia), whereas IL-10 modulates TNF-alpha production and/or release as a mechanism of hypothermia attenuation. IL-1beta and IL-6 are typically regarded as endogenous pyrogens, but may induce hypothermia during viral and bacterial inflammation. A role for endogenous IFN-gamma in hypothermia has not been demonstrated, but injection of this cytokine potentiates hypothermia through augmented production of other cytokines. It is clear that additional research is required in this area. Suggested areas for future research include a determination of the final mediator of hypothermia and its specific anatomical site of action as well as the role of cytokines in the regulation of hypothermia under non-inflammatory conditions.
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PMID:Hypothermia in systemic inflammation: role of cytokines. 1497 94

We previously showed that beta 2 microglobulin knockout mice depleted of NK cells by treatment with anti-asialoGM1 (beta2MKO/alphaAsGM1 mice) are resistant to sepsis caused by cecal ligation and puncture (CLP). beta2MKO mice possess multiple immunological defects including depletion of CD8+ T cells. This study was designed to determine the contribution of CD8+ T and NK cell deficiency to the resistance of beta2MKO/alphaAsGM1 mice to CLP-induced injury. beta2MKO/alphaAsGM1 mice and CD8 knockout mice treated with anti-asialoGM1 (CD8KO/alphaAsGM1 mice) survived significantly longer than wild-type mice following CLP. Improved long-term survival was also observed in wild-type mice rendered CD8+ T/NK cell-deficient by treatment with both anti-CD8alpha and anti-asialoGM1. Blood gas analysis and body temperature measurements showed that CD8+ T and NK cell-deficient mice have significantly reduced metabolic acidosis and less hypothermia compared to control mice at 18 h after CLP. CD8+ T/NK cell-deficient mice also showed an attenuated proinflammatory response as indicated by decreased expression of mRNAs for IL-1, IL-6 and MIP-2 in spleen and heart. IL-6, KC and MIP-2 levels in blood and peritoneal fluid were also significantly decreased CD8+ T/NK cell-deficient mice compared to controls. CD8+ T/NK cell-deficient mice exhibited decreased bacterial concentrations in blood, but not in peritoneal fluid or lung, compared to wild-type controls. These data show that mice depleted of CD8+ T and NK cells exhibit survival benefit, improved physiologic function and an attenuated proinflammatory response following CLP that is comparable to beta2M/alphaAsGM1 mice.
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PMID:Mice depleted of CD8+ T and NK cells are resistant to injury caused by cecal ligation and puncture. 1544 11

Infectious challenge triggers a broad array of coordinated changes within the host organism, including alterations in sleep-wake behavior and body temperature. Pro-inflammatory cytokines orchestrate many of the behavioral, metabolic, and endocrine responses to immune challenge. Although interleukin (IL)-6 mediates several aspects of sickness behavior, a role for this cytokine as a mediator of alterations in sleep in response to immune challenge has not been established. We evaluated sleep-wake behavior and core body temperature of IL-6-deficient (IL-6 KO; B6.129S6-Il6tm1Kopf) mice and C57BL/6J control mice after intraperitoneal (IP) administration of 10 microg lipopolysaccharide (LPS). Because feedback mechanisms that regulate responses to immune challenge exhibit circadian rhythms, we evaluated responses to LPS administered at the beginning of both the light and dark portions of the light:dark cycle. LPS-induced increases in non-rapid eye movements sleep (NREMS) of both mouse strains, but this increase was less pronounced in IL-6 KO mice than in C57BL/6J mice. Strain differences in LPS-induced increases in NREMS were greatest after light-onset administration. During the 12 h light period, NREMS of C57BL/6J mice increased from 53.0+/-1.7% of recording time after vehicle to 65.4+/-1.4% of recording time after LPS. During this same time period, NREMS of IL-6 KO mice increased from 50.5+/-1.8% after vehicle to only 52.4+/-1.8% of recording time after LPS. REMS of both mouse strains was suppressed to the same extent after LPS, irrespective of timing of administration. LPS-induced fever in C57BL/6J mice, with peak magnitude of 1.4+/-0.3 degrees C and 1.8+/-0.2 degrees C after dark onset and light onset administration, respectively. In contrast, this dose of LPS-induced profound hypothermia in IL-6 KO mice, with nadirs of hypothermia reaching 4.9+/-1.0 degrees C after injection at dark onset and 2.2+/-0.5 degrees C after administration at light onset. These results indicate that IL-6 mediates some of the effects of LPS on NREMS and body temperature of mice, and that the magnitude and duration of these effects differ as a function of the time at which the challenge is given.
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PMID:Diurnal variation of lipopolysaccharide-induced alterations in sleep and body temperature of interleukin-6-deficient mice. 1558 37

Traumatic brain injury (TBI) initiates a cascade of cellular and molecular responses including both pro- and anti-inflammatory. Although post-traumatic hypothermia has been shown to improve outcome in various models of brain injury, the underlying mechanisms responsible for these effects have not been clarified. In this study, inflammation cDNA arrays and semi-quantitative RT-PCR were used to detect genes that are differentially regulated after TBI. In addition, the effect of post-traumatic hypothermia on the expression of selective genes was also studied. Rats (n = 6-8 per group) underwent moderate fluid-percussion (F-P) brain injury with and without hypothermic treatment (33 degrees C/3 h). RNA from 3-h or 24-h survival was analyzed for the expression of IL1-beta, IL2, IL6, TGF-beta2, growth-regulated oncogene (GRO), migration inhibitory factor (MIF), and MCP (a transcription factor). The interleukins IL-1beta, IL-2, and IL-6 and TGF-beta and GRO were strongly upregulated early and transiently from 2- to 30-fold over sham at 3 h, with normalization by 24 h. In contrast, the expressions of MIF and MCP were both reduced by TBI compared to sham. Post-traumatic hypothermia had no significant effect on the acute expression of the majority of genes investigated. However, the expression of TGF-beta2 at 24 h was significantly reduced by temperature manipulation. The mechanism by which post-traumatic hypothermia is protective may not involve a general genetic response of the inflammatory genes. However, specific genes, including TGF-beta2, may be altered and effect cell death mechanisms after TBI. Hypothermia differentially regulates certain genes and may target more delayed responses underlying the secondary damage following TBI.
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PMID:The effect of therapeutic hypothermia on the expression of inflammatory response genes following moderate traumatic brain injury in the rat. 1592 84

Transforming growth factor-beta (TGF-beta) is an important suppressor of inflammation. However, TGF-beta has also been found to promote secretion of inflammatory cytokines, and transgenic mice, which constitutively express TGF-beta in liver, have been found to be more susceptible to endotoxemia. To approach this apparent paradox, we investigated the role of hepatic TGF-beta1 in endotoxemia by utilising inducible TGF-beta1-transgenic mice that express TGF-beta1 under control of the C-reactive protein promoter. In contrast to non-transgenic littermates, administration of lipopolysaccharide (LPS) induced strongly increased expression of TGF-beta and acute phase proteins in the TGF-beta1-transgenic mice. Hepatic TGF-beta1-expression in the transgenic mice started an inflammatory cytokine cascade, marked by increased and prolonged secretion of TNF-alpha and IL-6 by hepatocytes. The inflammatory response of the TGF-beta1-transgenic mice to LPS was associated with high rates of mortality due to endotoxemic shock, marked by systemic hypotension and hypothermia. Endotoxemic shock was primarily mediated by TNF-alpha and IL-6, since inhibitory antibody to TNF-alpha or, more effectively, to IL-6 could reduce mortality in these mice. In conclusion, while TGF-beta-signalling to immune cells may suppress inflammatory effector function, TGF-beta-signalling to liver cells seems to promote LPS-stimulated secretion of inflammatory cytokines and to predispose for lethal endotoxemic shock.
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PMID:Hepatic over-expression of TGF-beta1 promotes LPS-induced inflammatory cytokine secretion by liver cells and endotoxemic shock. 1605 5

Macrophage-activating lipopeptide-2 (MALP-2) from Mycoplasma fermentans has been identified as a pathogen-associated molecular pattern of Mycoplasmas that causes activation of the innate immune system through the activation of the heterodimeric Toll-like receptors (TLRs)-2 and -6. The aim of this study was to characterize the ability of MALP-2 and a synthetic analog fibroblast-stimulating lipopeptide-1 (FSL-1; represents the NH2-terminal sequence of a lipoprotein from M. salivarium) to act as exogenous pyrogens, to induce formation of cytokines (endogenous pyrogens), and to cause sickness behavior, such as depressed motor activity, anorexia, and adipsia. For this purpose, body temperature, activity, food intake, and water intake were recorded for 3 days by use of telemetry devices in several groups of rats treated with MALP-2/FSL-1 or the respective control solutions. Intraperitoneal injections of FSL-1 caused fever at doses of 10 or 100 microg/kg, which was preceded by a pronounced phase of hypothermia in response to a dose of 1,000 microg/kg. The maximal fever (a peak of 1.5 degrees C above baseline) was caused by the 100 microg/kg dose with almost identical responses to both MALP-2 and FSL-1. Fever was accompanied by pronounced rises of the proinflammatory cytokines TNF and IL-6 in plasma. Treatment with the TLR-2 and -6 agonists further induced a dose-dependent manifestation of anorexia and adipsia, as well as a reduction of motor activity. We could thus demonstrate that activation of TLR-2 and -6 can induce systemic inflammation in rats accompanied by the classical signs of brain-controlled illness responses.
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PMID:Pyrexia, anorexia, adipsia, and depressed motor activity in rats during systemic inflammation induced by the Toll-like receptors-2 and -6 agonists MALP-2 and FSL-1. 1615 16

Elevated circulating cytokines are observed in heatstroke patients, suggesting a role for these substances in the pathophysiological responses of this syndrome. Typically, cytokines are determined at end-stage heatstroke such that changes throughout progression of the syndrome are poorly understood. We hypothesized that the cytokine milieu changes during heatstroke progression, correlating with thermoregulatory, hemodynamic, and tissue injury responses to heat exposure in the mouse. We determined plasma IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-12p40, IL-12p70, IFN-gamma, macrophage inflammatory protein-1alpha, TNF-alpha, corticosterone, glucose, hematocrit, and tissue injury during 24 h of recovery. Mice were exposed to ambient temperature of 39.5 +/- 0.2 degrees C, without food and water, until maximum core temperature (T(c,Max)) of 42.7 degrees C was attained. During recovery, mice displayed hypothermia (29.3 +/- 0.4 degrees C) and a feverlike elevation at 24 h (control = 36.2 +/- 0.3 degrees C vs. heat stressed = 37.8 +/- 0.3 degrees C). Dehydration ( approximately 10%) and hypoglycemia ( approximately 65-75% reduction) occurred from T(c,Max) to hypothermia. IL-1alpha, IL-2, IL-4, IL-12p70, IFN-gamma, TNF-alpha, and macrophage inflammatory protein-1alpha were undetectable. IL-12p40 was elevated at T(c,Max), whereas IL-1beta, IL-6, and IL-10 inversely correlated with core temperature, showing maximum production at hypothermia. IL-6 was elevated, whereas IL-12p40 levels were decreased below baseline at 24 h. Corticosterone positively correlated with IL-6, increasing from T(c,Max) to hypothermia, with recovery to baseline by 24 h. Tissue lesions were observed in duodenum, spleen, and kidney at T(c,Max), hypothermia, and 24 h, respectively. These data suggest that the cytokine milieu changes during heat strain recovery with similarities between findings in mice and those described for human heatstroke, supporting the application of our model to the study of cytokine responses in vivo.
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PMID:Time course of cytokine, corticosterone, and tissue injury responses in mice during heat strain recovery. 1623 8

Hypothermia is often associated with compromised host defenses and infection. Deteriorations of immune functions related to hypothermia have been investigated, but the involvement of cytokines in host defense mechanisms and in infection remains unclear. We have previously shown that mild hypothermia modifies cytokine production by peripheral blood mononuclear cells. In this study, the effects of hypothermia on the monocytic production of several cytokines and nitric oxide (NO) were determined. Monocytes obtained from 10 healthy humans were cultured with lipopolysaccharide (LPS) under hypothermic (33 degrees C) or normothermic (37 degrees C) conditions for 48 hours. We performed flow cytometric analysis for simultaneous measurement of interleukin (IL)-8, IL-1beta, IL-6, IL-10, IL-12p70, and tumor necrosis factor (TNF)-alpha in culture supernatants. NO production was quantified as accumulation of nitrite in the medium by a colorimetric assay. Compared with normothermia, mild hypothermia raised the levels of IL-1beta, IL-6, IL-12p70, and TNF-alpha produced by monocytes stimulated with LPS. On calculating the ratios of these elevated cytokines to IL-10, however, only IL-12p70/IL-10 and TNF-alpha/IL-10 ratios were significantly elevated under hypothermic conditions. In contrast, hypothermia did not affect NO production. This study demonstrates that mild hypothermia affects the balance of cytokines produced by monocytes, leading to a pro-inflammatory state. Specifically, monocytic IL-12 and TNF-alpha appear to be involved in the immune alterations observed in mild hypothermia. However, the clinical significance of these phenomena remains to be clarified.
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PMID:Mild hypothermia promotes pro-inflammatory cytokine production in monocytes. 1636 38

Splenic nerve denervation abrogates enhanced splenic cytokine gene expression responses to acute heating, demonstrating that hyperthermia-induced activation of splenic sympathetic nerve discharge (SND) increases splenic cytokine gene expression. Hypothermia alters SND responses; however, the role of the sympathetic nervous system in mediating splenic cytokine gene expression responses to hypothermia is not known. The purpose of the present study was to determine the effect of hypothermia on the relationship between the sympathetic nervous system and splenic cytokine gene expression in anesthetized F344 rats. Gene expression analysis was performed using a microarray containing 112 genes, representing inflammatory cytokines, chemokines, cytokine/chemokine receptors and housekeeping genes. A subset of differentially expressed genes was verified by real-time RT-PCR analysis. Splenic SND was decreased significantly during cooling (core temperature decreased from 38 to 30 degrees C) in splenic-intact rats but remained unchanged in sham-cooled splenic-intact rats (core temperature maintained at 38 degrees C). Hypothermia upregulated the transcripts of several genes, including, chemokine ligands CCL2, CXCL2, CXCL10, and CCL20, and interleukins IL-1alpha, IL-1beta, and IL-6. Gene expression responses to hypothermia were similar for the majority of cytokine genes in splenic-intact and splenic-denervated rats. These results suggest that hypothermia-enhanced splenic cytokine gene expression is independent of splenic SND.
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PMID:Hypothermia-enhanced splenic cytokine gene expression is independent of the sympathetic nervous system. 1646 32


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