Critical role of CD14 for production of proinflammatory cytokines and cytokine inhibitors during sepsis with failure to alter morbidity or mortality

Myocardial Matrix Hydrogels Mitigate Negative Remodeling and Improve Function in Right Heart Failure Model

This study evaluates the effectiveness of myocardial matrix (MM) hydrogels in mitigating negative right ventricular (RV) remodeling in a rat model of RV heart failure. The goal was to assess whether a hydrogel derived from either the right or left ventricle could promote cardiac repair. Injured rat right ventricles were injected with either RV-or left ventricular-derived MM hydrogels. Both hydrogels improved RV function and morphology and reduced negative remodeling. This study supports the potential of injectable biomaterial therapies for treating RV heart failure.

CD14 signaling mediates lung immunopathology and mice mortality induced by Achromobacter xylosoxidans

Objective and design

Our research aimed to investigate the role of CD14 in pulmonary infection by Achromobacter xylosoxidans in an experimental murine model.

Methods

C57Bl/6 or CD14-deficient mice were infected intratracheally with non-lethal inoculum of A. xylosoxidans. At times 1, 3 and 7 days after infection, lungs, bronchoalveolar lavage and blood were collected. CD14 gene expression was determined by RT-PCR. The bacterial load in the lungs was assessed by counting colony forming units (CFU). Cytokines, chemokines, lipocalin-2 and sCD14 were quantified by the ELISA method. Inflammatory infiltrate was observed on histological sections stained with HE, and leukocyte subtypes were assessed by flow cytometry. In another set of experiments, C57Bl/6 or CD14-deficient mice were inoculated with lethal inoculum and the survival rate determined.

Results

CD14-deficient mice are protected from A. xylosoxidans-induced death, which is unrelated to bacterial load. The lungs of CD14-deficient mice presented a smaller area of tissue damage, less neutrophil and macrophage infiltration, less pulmonary edema, and a lower concentration of IL-6, TNF-α, CXCL1, CCL2 and CCL3 when compared with lungs of C57Bl/6 mice. We also observed that A. xylosoxidans infection increases the number of leukocytes expressing mCD14 and the levels of sCD14 in BALF and serum of C57Bl/6-infected mice.

Conclusions

In summary, our data show that in A. xylosoxidans infection, the activation of CD14 induces intense pulmonary inflammatory response resulting in mice death.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00011-022-01641-8.

CD14 inhibition improves survival and attenuates thrombo-inflammation and cardiopulmonary dysfunction in a baboon model of Escherichia coli sepsis

BACKGROUND

During sepsis, gram-negative bacteria induce robust inflammation primarily via lipopolysacharride (LPS) signaling through TLR4, a process that involves the glycosylphosphatidylinositol (GPI)-anchored receptor CD14 transferring LPS to the Toll-like receptor 4/myeloid differentiation factor 2 (TLR4/MD-2) complex. Sepsis also triggers the onset of disseminated intravascular coagulation and consumptive coagulopathy.

OBJECTIVES

We investigated the effect of CD14 blockade on sepsis-induced coagulopathy, inflammation, organ dysfunction, and mortality.

METHODS

We used a baboon model of lethal Escherichia (E) coli sepsis to study two experimental groups (n = 5): (a) E coli challenge; (b) E coli challenge plus anti-CD14 (23G4) inhibitory antibody administered as an intravenous bolus 30 minutes before the E coli.

RESULTS

Following anti-CD14 treatment, two animals reached the 7-day end-point survivor criteria, while three animals had a significantly prolonged survival as compared to the non-treated animals that developed multiple organ failure and died within 30 hours. Anti-CD14 reduced the activation of coagulation through inhibition of tissue factor-dependent pathway, especially in the survivors, and enhanced the fibrinolysis due to strong inhibition of plasminogen activator inhibitor 1. The treatment prevented the robust complement activation induced by E coli, as shown by significantly decreased C3b, C5a, and sC5b-9. Vital signs, organ function biomarkers, bacteria clearance, and leukocyte and fibrinogen consumption were all improved at varying levels. Anti-CD14 reduced neutrophil activation, cell death, LPS levels, and pro-inflammatory cytokines (tumor necrosis factor, interleukin (IL)-6, IL-1β, IL-8, interferon gamma, monocyte chemoattractant protein-1), more significantly in the survivors than non-surviving animals.

CONCLUSIONS

Our results highlight the crosstalk between coagulation/fibrinolysis, inflammation, and complement systems and suggest a protective role of anti-CD14 treatment in E coli sepsis.

Identification, molecular characterization, expression analysis and wound-healing ability of multifunctional calreticulin from big-belly seahorse Hippocampus abdominalis

Calreticulin (CRT) is a multifunctional ubiquitous protein that is widely presented in all cells in eukaryotes except erythrocytes. CRT is well known for diverse cellular functions such as endoplasmic reticulum (ER)-specialized protein quality control during protein synthesis and folding, in-vivo Ca²⁺ homeostasis, antigen presentation, phagocytosis, wound-healing, proliferation, adhesion, and migration of cells. In the current study, we identified CRT from Hippocampus abdominalis (HaCRT) and analyzed expression profiles and functional properties. The cDNA sequence of HaCRT was identified with an open reading frame of 1226 bp. The molecular weight of HaCRT was estimated as 49 kDa. The in-silico study revealed conserved sequence arrangements such as two CRT signature motifs (5'-KHEQSIDCGGGYVKVF-3' and 5'-LMFGPDICG-3'), triplicate repeats (5'-IKDPEAKKPEDWD-3', 5'-IPDPDDTKPEDWD-3', 5'-IPDPDAKKPDDWD-3'), signal peptide and an ER-targeting 5'-KDEL-3' sequence of HaCRT. Close sequence similarity of HaCRT was observed with Hippocampus comes from phylogenetic analysis and pairwise sequence comparison. From quantitative polymerase chain reaction (qPCR) results, HaCRT was ubiquitously distributed in all tested tissues and expression levels of HaCRT were significantly modulated in blood, liver and gill tissues after stimulation with Streptococcus iniae, Edwardsiella tarda, polyinosinic:polycytidylic acid, and lipopolysaccharides. Bacterial- and pathogen-associated molecular patterns-binding activities were observed with recombinant HaCRT (rHaCRT). The treatment of murine macrophages with rHaCRT induced the expression of immune genes, such as tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), and interleukin-1β (IL-1β). Furthermore, rHaCRT exhibited wound-healing ability. Based on the results from the above study, we suggest that HaCRT play an indispensable role in the immunity of big-belly seahorses by recognition and elimination of pathogens as well as the tissue repairing process.

Transcriptome landscape of myeloid cells in human skin reveals diversity, rare populations and putative DC progenitors

BACKGROUND

The heterogeneous functions of dermal myeloid cells in antigen presentation, and scavenging pathogens and cell debris places them centrally in cutaneous inflammation. Single cell transcriptomics can provide new understanding of the heterogeneity and function of yet incompletely understood human dermal myeloid cell subsets.

OBJECTIVE

Investigate the transcriptome landscape of myeloid cells in healthy human skin.

METHODS

Single cell RNA-sequencing was performed on skin biopsies from ten healthy donors and analyzed to identify myeloid cell populations.

RESULTS

One LIN^- HLA-DR⁺ cluster with expression of myeloid-specific genes was identified as a cluster of myeloid cells. Upon reanalysis of this cluster, we identified three macrophage subsets, marked by high expression of CCR1, MARCO or TREM2; and six dendritic cell subsets, marked by high expression of CLEC9A, CXorf21, MCOLN2, LAMP3, KIAA0101 and Langerin, representing respectively cDC1, two subsets of cDC2, a novel DC type, a cluster of proliferating DC, and a Langerhans cell subset. GO term analysis indicated specialized functions for the discrete rare populations of myeloid cells: TREM2 Mφ in lipid metabolism and LAMP3 DC as a mature cDC. Proliferating DCs appeared to represent cDC2 progenitors.

CONCLUSION

The transcriptional landscape of myeloid cell populations in human skin indicates several, novel populations with specialized functions, as well as a rare proliferating DC population that likely accounts for local regeneration or expansion of dermal DCs. We provide robust gene expression markers for each of these populations that should permit better understandings of their roles in various homeostatic and pathologic immune processes in the skin.

Delayed Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Inhibition by Trametinib Attenuates Systemic Inflammatory Responses and Multiple Organ Injury in Murine Sepsis

OBJECTIVE

The mitogen-activated protein kinase/extracellular signal-regulated kinase signaling pathway is an essential component of innate immunity necessary for mediating proinflammatory responses in the setting of sepsis. We previously demonstrated that the mitogen-activated protein kinase 1/2 inhibitor trametinib prevents endotoxin-induced renal injury in mice. We therefore assessed efficacy of trametinib in a more clinically relevant experimental model of sepsis.

DESIGN

Controlled in vivo laboratory study.

SETTING

University animal research laboratory.

SUBJECTS

Male C57BL/6 mice.

INTERVENTIONS

Mice were subjected to cecal ligation and puncture to induce sepsis or underwent sham operation as controls. Six hours after cecal ligation and puncture, mice were randomized to four experimental groups as follows: 1) sham control; 2) sham control + trametinib (1 mg/kg, IP); 3) cecal ligation and puncture; and 4) cecal ligation and puncture + trametinib. All animals received buprenorphine (0.05 mg/kg, SC) and imipenem/cilastatin (14 mg/kg, SC) in 1.5 mL of warm saline (40 mL/kg) at the 6-hour time point. Mice were euthanized at 18 hours after induction of cecal ligation and puncture.

MEASUREMENTS AND MAIN RESULTS

Trametinib inhibition of mitogen-activated protein kinase/extracellular signal-regulated kinase signaling 6 hours after cecal ligation and puncture attenuated increases in circulating proinflammatory cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-6, and granulocyte macrophage colony-stimulating factor) and hypothermia at 18 hours. Trametinib also attenuated multiple organ injury as determined by serum creatinine, alanine aminotransferase, lactate dehydrogenase, and creatine kinase. At the organ level, trametinib completely restored peritubular capillary perfusion in the kidney. Restoration of microvascular perfusion was associated with reduced messenger RNA expression of well-characterized markers of proximal tubule injury. mitogen-activated protein kinase/extracellular signal-regulated kinase blockade attenuated cecal ligation and puncture-mediated up-regulation of cytokines (tumor necrosis factor-α, interleukin-1β) and restored interleukin-6 to control levels in the renal cortex, indicating the protective effects on the proximal tubule occur primarily through modulation of the proinflammatory response in sepsis.

CONCLUSIONS

These data reveal that the mitogen-activated protein kinase/extracellular signal-regulated kinase inhibitor trametinib attenuates systemic inflammation and multiple organ damage in a clinically relevant model of sepsis. Because trametinib has been safely used in humans, we propose that this drug might represent a translatable approach to limit organ injury in septic patients.

Perspectives for Monocyte/Macrophage-Based Diagnostics of Chronic Inflammation

Low-grade chronic inflammation underlies the development of the most dangerous cardiometabolic disorders including type 2 diabetes and its vascular complications. In contrast to acute inflammation induced by bacteria and viruses, chronic inflammation can be driven by abnormal reaction to endogenous factors, including Th2 cytokines, metabolic factors like advanced glycation end products (AGEs), modified lipoproteins, or hyperglycemia. The key innate immune cells that recognize these factors in blood circulation are monocytes. Inflammatory programming of monocytes which migrate into tissues can, in turn, result into generation of tissue macrophages with pathological functions. Therefore, determination of the molecular and functional phenotype of circulating monocytes is a very promising diagnostic tool for the identification of hidden inflammation, which can precede the development of the pathology. Here we propose a new test system for the identification of inflammatory programming of monocytes: surface biomarkers and ex vivo functional system. We summarize the current knowledge about surface biomarkers for monocyte subsets, including CD16, CCR2, CX3CR1, CD64, stabilin-1 and CD36, and their association with inflammatory human disorders. Furthermore, we present the design of an ex vivo monocyte-based test system with minimal set of parameters as a potential diagnostic tool for the identification of personalized inflammatory responses.

The immunobiology of toll-like receptor 4 agonists: from endotoxin tolerance to immunoadjuvants

Lipopolysaccharide (LPS, endotoxin) is a structural component of the gram-negative outer membrane. The lipid A moiety of LPS binds to the LPS receptor complex expressed by leukocytes, endothelial cells, and parenchymal cells and is the primary component of gram-negative bacteria that is recognized by the immune system. Activation of the LPS receptor complex by native lipid A induces robust cytokine production, leukocyte activation, and inflammation, which is beneficial for clearing bacterial infections at the local level but can cause severe systemic inflammation and shock at higher challenge doses. Interestingly, prior exposure to LPS renders the host resistant to shock caused by subsequent LPS challenge, a phenomenon known as endotoxin tolerance. Treatment with lipid A has also been shown to augment the host response to infection and to serve as a potent vaccine adjuvant. However, the adverse effects associated with the pronounced inflammatory response limit the use of native lipid A as a clinical immunomodulator. More recently, analogs of lipid A have been developed that possess attenuated proinflammatory activity but retain attractive immunomodulatory properties. The lipid A analog monophosphoryl lipid A exhibits approximately 1/1,000th of the toxicity of native lipid A but retains potent immunoadjuvant activity. As such, monophosphoryl lipid A is currently used as an adjuvant in several human vaccine preparations. Because of the potency of lipid A analogs as immunoadjuvants, numerous laboratories are actively working to identify and develop new lipid A mimetics and to optimize their efficacy and safety. Based on those characteristics, lipid A analogs represent an attractive family of immunomodulators.

Double blockade of CD14 and complement C5 abolishes the cytokine storm and improves morbidity and survival in polymicrobial sepsis in mice

Sepsis and septic shock, caused by an excessive systemic host-inflammatory response, are associated with high morbidity and mortality. The complement system and TLRs provide important pattern recognition receptors initiating the cytokine storm by extensive cross-talk. We hypothesized that double blockade of complement C5 and the TLR coreceptor CD14 could improve survival of experimental polymicrobial sepsis. Mice undergoing cecal ligation and puncture (CLP)-induced sepsis were treated with neutralizing anti-CD14 Ab biG 53, complement C5 inhibitor coversin (Ornithodoros moubata C inhibitor), or a combination thereof. The inflammatory study (24-h observation) revealed statistically significant increases in 22 of 24 measured plasma biomarkers in the untreated CLP group, comprising 14 pro- and anti-inflammatory cytokines and 8 chemokines, growth factors, and granulocyte activation markers. Single CD14 or C5 blockade significantly inhibited 20 and 19 of the 22 biomarkers, respectively. Combined CD14 and C5 inhibition significantly reduced all 22 biomarkers (mean reduction 85%; range 54-95%) compared with the untreated CLP group. Double blockade was more potent than single treatment and was required to significantly inhibit IL-6 and CXCL1. Combined inhibition significantly reduced morbidity (motility and eyelid movement) and mortality measured over 10 d. In the positive control CLP group, median survival was 36 h (range 24-48 h). Combined treatment increased median survival to 96 h (range 24-240 h) (p = 0.001), whereas survival in the single-treatment groups was not significantly increased (median and range for anti-CD14 and anti-C5 treatment were 36 h [24-48 h] and 48 h [24-96 h]). Combined with standard intervention therapy, specific blockade of CD14 and C5 might represent a promising new therapeutic strategy for treatment of polymicrobial sepsis.

Autonomic regulation of cellular immune function

The nervous system and the immune system (IS) are two integrative systems that work together to detect threats and provide host defense, and to maintain/restore homeostasis. Cross-talk between the nervous system and the IS is vital for health and well-being. One of the major neural pathways responsible for regulating host defense against injury and foreign antigens and pathogens is the sympathetic nervous system (SNS). Stimulation of adrenergic receptors (ARs) on immune cells regulates immune cell development, survival, proliferative capacity, circulation, trafficking for immune surveillance and recruitment, and directs the cell surface expression of molecules and cytokine production important for cell-to-cell interactions necessary for a coordinated immune response. Finally, AR stimulation of effector immune cells regulates the activational state of immune cells and modulates their functional capacity. This review focuses on our current understanding of the role of the SNS in regulating host defense and immune homeostasis. SNS regulation of IS functioning is a critical link to the development and exacerbation of chronic immune-mediated diseases. However, there are many mechanisms that need to be further unraveled in order to develop sound treatment strategies that act on neural-immune interaction to resolve or prevent chronic inflammatory diseases, and to improve health and quality of life.

Protein kinase G oxidation is a major cause of injury during sepsis

Sepsis is a common life-threatening clinical syndrome involving complications as a result of severe infection. A cardinal feature of sepsis is inflammation that results in oxidative stress. Sepsis in wild-type mice induced oxidative activation of cGMP-dependent protein kinase 1 alpha (PKG Iα), which increased blood vessel dilation and permeability, and also lowered cardiac output. These responses are typical features of sepsis and their combined effect is a lowering of blood pressure. This hypotension, a hallmark of sepsis, resulted in underperfusion of end organs, resulting in their damage. A central role for PKG Iα oxidative activation in injury is supported by oxidation-resistant Cys42Ser PKG Iα knock-in mice being markedly protected from these clinical indices of injury during sepsis. We conclude that oxidative activation of PKG Iα is a key mediator of hypotension and consequential organ injury during sepsis.

Microglial CD14 activated by iNOS contributes to neuroinflammation in cerebral ischemia

Stroke is one of the most frequent causes of death and disability worldwide. Cerebral ischemia is the major insult of stroke and induces acute inflammation by triggering excessive production of proinflammatory cytokines, leading to the exacerbation of primary brain damage. Toll-like receptor (TLR)- and nitric oxide-mediated signaling pathways have been identified under ischemic stress. However, the interaction between these two pathways in controlling proinflammatory cytokines has not been well addressed during cerebral ischemia. Adult male C57BL/6 mice were subjected to middle cerebral artery occlusion (MCAO) for stroke induction. The MCAO procedure resulted in a significant infarct in the brain after 24h. The infarcted side of the brain had marked elevation of TNF-α gene and protein expression, compared to the sham brain. The expression of CD14, a co-receptor of TLR4, was induced by MCAO, while the expression of TLR4 remained unchanged. The levels of inducible nitric oxide synthase (iNOS) and nitrotyrosine were also upregulated in the infracted side of the brain. Correspondingly, exposing murine microglial BV2 cells to hypoxia (1% O2) for 20h resulted in an increased expression of TNF-α, CD14, iNOS, and nitrotyrosine. When BV2 cells were treated with l-canavanine, an iNOS selective inhibitor, the elevation of TNF-α and CD14 induced by hypoxia was inhibited. This inhibition was associated with an increase of IκB. These results suggest that the upregulation of TNF-α production in ischemic stroke is partially through increasing iNOS, and then CD14 expression leading to the activation of the NF-κB pathway in microglia.

Interleukin 5 is protective during sepsis in an eosinophil-independent manner

RATIONALE

The immune response in sepsis is characterized by overt immune dysfunction. Studies indicate immunostimulation represents a viable therapy for patients. One study suggests a potentially protective role for interleukin 5 (IL-5) in sepsis; however, the loss of eosinophils in this disease presents a paradox.

OBJECTIVES

To assess the protective and eosinophil-independent effects of IL-5 in sepsis.

METHODS

We assessed the effects of IL-5 administration on survival, bacterial burden, and cytokine production after polymicrobial sepsis. In addition, we examined the effects on macrophage phagocytosis and survival using fluorescence microscopy and flow cytometry.

MEASUREMENTS AND MAIN RESULTS

Loss of IL-5 increased mortality and tissue damage in the lung, IL-6 and IL-10 production, and bacterial burden during sepsis. Therapeutic administration of IL-5 improved mortality in sepsis. Interestingly, IL-5 administration resulted in neutrophil recruitment in vivo. IL-5 overexpression in the absence of eosinophils resulted in decreased mortality from sepsis and increased circulating neutrophils and monocytes, suggesting their importance in the protective effects of IL-5. Furthermore, novel data demonstrate IL-5 receptor expression on neutrophils and monocytes in sepsis. IL-5 augmented cytokine secretion, activation, phagocytosis, and survival of macrophages. Importantly, macrophage depletion before the onset of sepsis eliminated IL-5-mediated protection. The protective effects of IL-5 were confirmed in humans, where IL-5 levels were elevated in patients with sepsis. Moreover, neutrophils and monocytes from patients expressed the IL-5 receptor.

CONCLUSIONS

Taken together, these data support a novel role for IL-5 on noneosinophilic myeloid populations, and suggest treatment with IL-5 may be a viable therapy for sepsis.

Stratification is the key: inflammatory biomarkers accurately direct immunomodulatory therapy in experimental sepsis

OBJECTIVE

This study examined the effectiveness of prospective stratification to identify and target high-dose glucocorticoid therapy for subjects developing lethal sepsis.

DESIGN

Prospective, randomized, laboratory-controlled experiment.

SETTING

University research laboratory.

SUBJECTS

Adult female outbred CD-1 mice.

INTERVENTIONS

Mice (n = 88) were subjected to sepsis induced by cecal ligation and puncture (CLP). Mice were prospectively divided into two groups, predicted to die (P-DIE) or predicted to live (P-LIVE), based on plasma levels of interleukin (IL)-6 obtained 6 hours after CLP. Following stratification, dexamethasone (DEX, 2.5 mg/kg, two doses) was administered to half the animals in each group whereas the other half received saline.

MEASUREMENTS AND MAIN RESULTS

Without stratification, DEX conferred no benefit. In the P-DIE group, none of saline-treated mice lived whereas 40% of the DEX-treated mice survived. Of the nonsurvivors, 67% had death delayed by 24-48 hours compared with saline-treated mice. Twenty-four hours post-CLP, the lymphocyte count was higher in the P-DIE than in the P-LIVE mice regardless of treatment status, whereas the opposite trend was noted for neutrophils. Plasma cytokine and cytokine inhibitor levels in the saline-treated animals showed that levels in the P-DIE group were higher than those in the P-LIVE group (e.g., 60 vs. 10 ng/mL for IL-6 and 453 vs.129 ng/mL for IL-1 receptor antagonist). Interestingly, DEX therapy did not decrease 24 hours post-CLP circulating cytokines in either the P-DIE or the P-LIVE group.

CONCLUSIONS

Following CLP-induced sepsis, early and accurate survival prediction allows targeted immunosuppression that improves survival. Better survival occurred without suppression of the typical proinflammatory mediators, suggesting that the deaths were not mediated by excessive cytokine-driven inflammation. Nonspecific anti-inflammatory/immunosuppressive treatment administered to more rigorously defined cohorts may be more successful than mediator-specific drugs used indiscriminately.

Milk fat globule epidermal growth factor-factor VIII is down-regulated in sepsis via the lipopolysaccharide-CD14 pathway

Phagocytosis prevents the release of potentially harmful or immunogenic materials from dying cells. Milk fat globule epidermal growth factor (EGF)-factor VIII (MFG-E8) mediates the clearance of apoptotic cells. We have previously shown that the administration of MFG-E8-rich exosomes from immature dendritic cells promotes the phagocytosis of apoptotic cells and improves survival in sepsis. Because endotoxin is elevated in polymicrobial sepsis, we hypothesized that down-regulation of MFG-E8 is mediated via the LPS-CD14 pathway, eventually leading to the accruement of apoptotic cells. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in CD14-deficient (CD14(-/-)), TLR4-mutated and wild-type (WT) mice. In addition, endotoxemia was elicited by i.p. injection of LPS. LPS was also neutralized by pretreating CLP-induced WT mice with polymyxin B. Splenic MFG-E8 expression, phagocytic activity, and apoptosis were assessed 5 and 20 h after CLP or 5 h after LPS administration. In septic WT mice, MFG-E8 mRNA and protein levels were suppressed by 49 and 33%, respectively. Endotoxemia reduced MFG-E8 mRNA expression in a dose dependent manner and the down-regulation of MFG-E8 mRNA expression in CLP-induced sepsis was attenuated by polymyxin B. This CLP-induced suppression was not observed in both CD14(-/-) and TLR4-mutated mice. CLP significantly decreased phagocytic activity of peritoneal macrophages in WT (by 30%), but not in CD14(-/-) mice. CLP also induced significant apoptosis in the spleen of WT (by 61%), but less in CD14(-/-) mice. Thus, MFG-E8 production is down-regulated in sepsis by LPS-CD14 dependent fashion, leading to a reduction of phagocytosis of apoptotic cells.

Sepsis, apoptosis and complement

Programmed cell death (apoptosis) is a prominent feature in human and experimental sepsis, especially as it involves the lymphoid system with resulting immunoparalysis. In addition, sepsis is associated with strong activation of the complement system, resulting in generation of the powerful anaphylatoxin, C5a, as well as the upregulation of the C5a receptor (C5aR) in a variety of different organs. The consequences of C5a interactions with C5aR can be directly linked to apoptosis of thymocytes and adrenal medullary cells after cecal ligation and puncture (CLP)-induced sepsis in rodents, as well as with other accompanying complications of CLP: cardiac dysfunction, consumptive coagulopathy, organ dysfunction, and lethality. This communication reviews the evidence for the adverse roles of C5a and C5aR in the setting of experimental sepsis and linkages to the various complications of sepsis, especially apoptosis as well as the roles of the two C5a receptors (C5aR and C5L2) in experimental sepsis.

CD14-159 C allele is associated with increased risk of mortality after burn injury

Although comprehension of postburn pathophysiology has grown in recent years, we are still unable to accurately identify burn patients who are at an increased risk of infectious complications and death. This unexplained variation is likely influenced by heritable factors; the genetic predisposition for death from infection has been estimated as greater than that for cardiovascular disease or cancer. Identify genetic variants associated with increased mortality after burn injury. A total of 233 patients with burns of 15% of total body surface area or greater or smoke inhalation injury who survived more than 48 h after admission and were without significant nonburn-related trauma (injury severity score > or = 16), traumatic or anoxic brain injury, or spinal cord injury. We examined the influence of genotype at five candidate loci (interleukin [IL]-1beta, IL-6, tumor necrosis factor-alpha, toll-like receptor 4, CD14) on mortality risk after burn injury. DNA was isolated from residual blood from laboratory draws and candidate genotypes were determined by real-time polymerase chain reaction using TaqMan probes. Clinical data were prospectively collected into a local, curated database. Allelic associations were analyzed by multivariate logistic regression. After adjustment for age, full-thickness burn size, inhalation injury, ethnicity, and sex, carriage of the CD14-159 C allele imparted at least a 1.3-fold increased risk for death after burn injury, relative to TT homozygotes (adjusted odds ratio, 2.9; 95% confidence interval, 1.3-6.8; P = 0.01). This association was stronger (adjusted odds ratio, 3.3; 95% confidence interval, 1.3-8.4; P = 0.01) when the analysis was conducted only on deaths accompanied by severe sepsis. In addition, a gene dosage effect for increased mortality was apparent for carriage of the CD14-159 C allele (P = 0.006). The gene dosage effect remained when white, Hispanic, or African American patients were analyzed independently, although statistical significance was not achieved in the subgroup analysis. None of the other single nucleotide polymorphisms examined were significantly associated with mortality. These data provide strong evidence that a CD14 promoter allele that is known to impart lower baseline and induced CD14 transcription also affects mortality risk after burn injury. A potential (although untested) mechanism for our observation is that reduced signaling through CD14/toll-like receptor 4 in response to challenge by gram-negative bacteria after burns results in a blunted innate immune response and subsequent increased likelihood for systemic infection and death.

Murine hematopoietic stem cells and progenitors express adrenergic receptors

Association between the nervous and immune system is well documented. Immune cells originate within the bone marrow that is innervated. Thermal injury induces adrenergic stimulation, augments monocytopoiesis and alters the beta-adrenergic receptor (AR) profile of bone marrow monocyte committed progenitors. This provides an impetus to study AR expression in hematopoietic progenitors along myeloid lineage. Using FACS analysis and confocal microscopy, we report the expression of alpha1-, alpha2- and beta(2)-AR in enriched populations of ER-MP209(+) and ER-MP12(+) myeloid progenitors, CD117(+) and CD34(+) multi-potential progenitors and more importantly pluripotent stem cells suggesting a plausible role for catecholamine in hematopoietic development.

The role of complement C3 opsonization, C5a receptor, and CD14 in E. coli-induced up-regulation of granulocyte and monocyte CD11b/CD18 (CR3), phagocytosis, and oxidative burst in human whole blood

The relative role of complement and CD14 in Escherichia coli-induced leukocyte CD11b up-regulation, phagocytosis, and oxidative burst in human whole blood was examined. The highly specific thrombin inhibitor lepirudin was used as anticoagulant, as it does not affect complement activation. Complement inhibition at the level of C3 (anti-C2 and anti-factor D) and C5 (C5a receptor antagonist and anti-C5/C5a) efficiently inhibited CD11b up-regulation, phagocytosis, and oxidative burst in granulocytes. Monocyte activation was generally less complement-dependent, but when C3 activation was blocked, a pronounced inhibition of phagocytosis and oxidative burst was obtained. Only the combination of anti-C2 and antifactor D blocked E. coli C3 opsonization completely. Whole E. coli, disrupted E. coli, and the C3-convertase activator cobra venom factor up-regulated CD11b rapidly on both cell types, proportional to their complement activation potential in the fluid phase. In comparison, purified LPS at concentrations comparable with that present in the E. coli preparations did not activate complement. Oxidative burst was induced only by whole bacteria. Finally, the combination of complement inhibition and anti-CD14 completely blocked E. coli-induced granulocyte and monocyte CD11b up-regulation and quantitatively, virtually abolished phagocytosis. The results indicate that complement and CD14, despite differential effects on granulocytes and monocytes, are the two crucial, quantitative factors responsible for E. coli-induced CD11b, phagocytosis, and oxidative burst in both cell types.

C3 binding glycoprotein from Cuscuta europea induced different cytokine profiles from human PBMC compared to other plant and bacterial immunomodulators

The immunomodulatory properties of bioactive agents include the ability to induce cytokine production by the activated target cell. The effect of immunomodulatory C3 binding glycoprotein isolated from Cuscuta europea on the induction of human PBMC cytokine synthesis and the cell viability was investigated. Isolated PBMC from healthy donors were cultured for 24 h with C3bgp. We also studied the influence of C3bgp on the cytokine production in LPS, PHA, PWM and Dex treated PBMC. The quantitative determination of TNF-alpha, IL-12, IL-6 and IL-10 was performed in culture supernatant by ELISA. Results obtained demonstrated that C3bgp induced proinflammatory and immunoregulatory cytokine production, in the highest degree IL-12, followed by IL-6 and in lower degree TNF-alpha. IL-12 quantity was significantly increased in C3bgp stimulated cultures in comparison with LPS, PHA and PWM stimulated PBMC. C3bgp also increased IL-12 in PHA or PWM stimulated cultures, but not in LPS stimulated culture. C3bgp significantly increased IL-6 production compared to the PHA and PWM but not to LPS stimulation. On the other side, C3bgp inhibited IL-10 production after LPS, PHA and PWM stimulation. Cell viability in C3bgp stimulated cultures retained on the same level from 72 to 120 h of culturing, in contrast to LPS and PHA stimulated cultures. Based on the results presented, we conclude that the C3bgp exhibited immunomodulatory properties on the human PBMC. The ability of PDTC and Dex to down-regulate the effect of C3bgp on the proinflammatory cytokine production suggests that a part of the mechanism of action of C3bgp is mediated through NF-kB signal transduction pathway.

High interleukin 12 and low interleukin 10 production after in vitro stimulation detected in sepsis survivors

OBJECTIVE

To evaluate viability of isolated peripheral blood mononuclear cells (PBMC) and production of cytokines in vitro after stimulation as prognostic factors for survival in sepsis patients.

DESIGN

Prospective study of the biological response of PBMC in the onset of severe sepsis.

SETTING

Research laboratory of molecular biology and immunology and university hospital ICU, Faculty of Medicine, Trakia University.

PATIENTS

Twenty-three patients meeting the criteria for severe sepsis, and 14 control subjects.

INTERVENTIONS

Isolated PBMC were stimulated in vitro with: C3-binding glycoprotein (C3bgp; 30 microg), lipopolysaccharide (30 microg), phytohemagglutinin (20 microg), pokeweed mitogen (30 microg), and dexamethasone (500 microg).

MEASUREMENTS AND RESULTS

We measured the levels of interleukins (IL) 6, 10, and 12 in culture supernatants. Stimulation with C3bgp and phytohemagglutinin led to significantly lower PBMC secretion of IL-6 in nonsurvivors than in survivors and healthy donors. Stimulation with C3bgp, lipopolysaccharide, and pokeweed mitogen considerably reduced IL-12 production in nonsurvivors. Stimulation with lipopolysaccharide and pokeweed mitogen caused immune cells in nonsurvivors to produce higher levels of IL-10 than in survivors. Survival of PBMC reduced viability for nonsurvivors' PBMC, both spontaneously and as induced by lipopolysaccharide or pokeweed mitogen.

CONCLUSIONS

The viability of PBMC at the onset of sepsis and enhanced production of IL-12 and diminished production of IL-10 after stimulation with all stimuli used may be a favorable prognostic factor in sepsis.

Cardiac Myocytes Activated by Septic Plasma Promote Neutrophil Transendothelial Migration

Cardiac myocytes isolated from rats with peritonitis (cecal ligation and perforation; CLP) promote PMN transendothelial migration. Herein, we assessed (1) the mechanisms involved in cardiac myocyte activation during peritonitis and (2) the means by which these activated myocytes promote PMN transendothelial migration. Plasma obtained from mice subjected to CLP (septic plasma) activated isolated cardiac myocytes as evidenced by (1) increased nuclear levels of nuclear factor-κB (NF-κB) and (2) their ability to promote PMN migration across endothelial cell monolayers. Pretreatment of septic plasma with an antibody against tumor necrosis factor-α (TNF-α), but not interleukin-1β (IL-1β), blunted the ability of septic plasma to activate the myocytes. However, septic plasma obtained from TNF-α–deficient mice could still activate the myocytes; an effect attenuated by an antibody against IL-1β. If the myocytes were pretreated with a proteasome inhibitor (MG 132) to prevent NF-κB activation, the myocyte-induced PMN transendothelial migration was compromised. The activated myocytes released platelet-activating factor (PAF), and myocyte-induced PMN migration was abrogated by a PAF receptor antagonist (WEB 2086). These myocytes also released the CXC chemokines LIX and KC; an event prevented by MG 132. Antibodies against LIX and KC abrogated the myocyte-induced PMN migration. However, LIX and KC, but not PAF, could promote PMN migration when used at concentrations produced by activated myocytes. These observations indicate that TNF-α and IL-1β are, in part, responsible for the ability of septic plasma to activate cardiac myocytes. The activated myocytes promote PMN transendothelial migration, an effect attributable to LIX and KC, and possibly, PAF.

Effect of CD14 blockade on endotoxin-induced acute lung injury in mice

CD14 functions as a cell surface receptor for endotoxin (lipopolysaccharide [LPS]) and is thought to have an essential role in innate immune responses to infection. Previous studies have revealed attenuation of the systemic response after sepsis by blocking CD14. In this study, we tested the hypothesis that CD14 blockade protects against inflammatory responses associated with LPS pneumonia. We examined the effect of an anti-murine CD14 monoclonal antibody (4C1) on the development of acute lung injury induced by intratracheal LPS in mice. We also measured the production of cytokines (tumor necrosis factor-alpha, interleukin-6, and macrophage inflammatory protein-2) and nitric oxide by murine peritoneal macrophages exposed to LPS in vitro. Nuclear factor (NF)-kappa B translocation was evaluated in nuclear extracts from lung homogenates. 4C1 significantly attenuated pulmonary edema and neutrophil emigration after LPS administration. The production of cytokines and nitric oxide by LPS-stimulated macrophages was significantly decreased by 4C1 treatment. NF-kappa B translocation induced by LPS instillation was also suppressed by 4C1. These results suggest that blockade of CD14 might attenuate acute lung injury after intratracheal instillation of LPS through the suppression of NF-kappa B translocation. The inhibitory effect of CD14 blockade on cytokine production and nitric oxide release of macrophages might contribute to the attenuation of lung injury.

Second messenger pathways in pulmonary host defense

The alveolar macrophage responds to bacterial infection with the production of inflammatory mediators that include TNFalpha. Early production of TNFalpha results in increased bacterial clearance, whereas too much TNFalpha results in many of the hallmarks of bacterial sepsis. TNFalpha production is regulated at many levels, including multiple signaling pathways, that lead to transcription, translation, and release of functional TNFalpha. Interactions of mitogen-activated protein (MAP) kinases, lipid signaling pathways, and oxidant-mediated mechanisms regulate the response of alveolar macrophages to infection. Animal models of sepsis support the central role played by macrophage-derived TNFalpha in sepsis.

Depressed interleukin-12-producing activity by monocytes correlates with adverse clinical course and a shift toward Th2-type lymphocyte pattern in severely injured male trauma patients

OBJECTIVE

To determine the effect of major trauma on the cytokine-producing activity of monocytes and CD4+ T cells in a homogeneous cohort of patients as well as to determine the relationship between monocyte and T-lymphocyte responses and clinical outcome.

SETTINGS

Surgical intensive care units of a trauma center and flow cytometry and experimental laboratories at a teaching hospital.

DESIGN

Prospective cohort clinical study with measurements of white cell cytokine-producing activity on days 2, 5, and 10 postinjury. The number of cytokine-producing CD14+ monocytes, CD4+, and CD8+ T cells were determined in whole blood using flow cytometry combined with the intracellular cytokine staining method. Basal and lipopolysaccharide-stimulated interleukin (IL)-12, tumor necrosis factor-alpha, IL-6, and IL-1alpha production by monocytes as well as basal and phorbol 12-myristate 13-acetate plus ionomycin-stimulated interferon-gamma, IL-4, and tumor necrosis factor-alpha production by T cells were determined on days 2, 5, and 10 postinjury and compared with similar measurements made in healthy control subjects.

PATIENTS

Twelve randomly selected black, male patients were enrolled in the study: mean injury severity score, 26; mean age, 35 yrs; mean Glasgow Coma Scale score, 13; systemic inflammatory response syndrome, 92%; sepsis, 42%; bronchial infection, 42%; and adult respiratory distress syndrome 25%.

MAIN RESULTS

After lipopolysaccharide stimulation, the number of IL-12-, tumor necrosis factor-alpha-, IL-1alpha-, and IL-6-producing CD14+ monocytes was 40% to 70% lower in trauma patients on postinjury days 2, 5, and 10 than in healthy control subjects. After phorbol 12-myristate 13-acetate stimulation, the number of IL-4-producing CD4+ cells increased three-fold in the trauma patients compared with healthy control subjects. In contrast, the number of interferon-gamma- or tumor necrosis factor-alpha-producing CD4+ and CD8+ T cells was not different between the patients and control subjects. The Th1/Th2 ratio was significantly lower in patients on all postinjury days than in the control subjects. A statistically significant inverse correlation was found between the number of IL-12-producing monocytes and IL-4-producing CD4+ T cells in trauma patients (p =.007, r2 =.47). This correlation was absent in control subjects. The degree of depressed capacity of monocyte IL-12 production on day 2 postinjury showed a statistically significant correlation with the development of adult respiratory distress syndrome, sepsis, or infections and also with the duration of systemic inflammatory response syndrome and sepsis.

CONCLUSIONS

Major trauma results in an early and marked decrease in monocyte cytokine-producing activity. The trauma-induced depression in IL-12 production by the mononuclear phagocyte system may promote T-cell commitment toward a Th2 pattern early after trauma. The appearance of the Th2 pattern is the result of elevated numbers of IL-4-producing cells without major alterations in T-cell interferon-gamma-producing capacity. The degree of alterations in monocyte and T-cell responses on day 2 postinjury correlates with the development of adverse clinical outcomes and the subsequent duration of the inflammatory response.

Lipopolysaccharide-binding protein and lipopolysaccharide receptor CD14 gene expression after thermal injury and its potential mechanism(s)

BACKGROUND

We hypothesized that lipopolysaccharide-binding protein (LBP) and lipopolysaccharide receptor CD14 would present a pair of key molecules in pathophysiologic alterations induced by low concentrations of endotoxin after trauma. The aim of this study was to investigate the relationship between endotoxin translocation and tissue LBP/CD14 messenger ribonucleic acid (mRNA) expression after burn injury, and to define the potential role of LBP/CD14 in mediating inflammatory mediator induction, as well as the pathogenesis of organ damage.

METHODS

Wistar rats were subjected to a 35% full-thickness scald injury, and tissue samples from liver, kidneys, lungs, and intestine were collected to measure LBP/CD14 and tumor necrosis factor-alpha (TNF-alpha) mRNA expression. Peritoneal macrophages were harvested by peritoneal lavage to determine CD14 mRNA expression.

RESULTS

It was found that endotoxin levels in liver, spleen, and lung increased markedly after thermal injury, with the highest level in liver. Both tissue LBP and CD14 mRNA expression increased markedly after burns, peaking at 12 hours, and then decreasing gradually. At 48 hours, LBP gene expression had a tendency to the baseline level, whereas CD14 mRNA expression increased again. Likewise, CD14 mRNA levels were up-regulated markedly in peritoneal macrophages. Conversely, gene expression of TNF-alpha in tissues elevated markedly after acute insults. There were positive correlations between lipopolysaccharide levels and LBP/CD14 mRNA as well as TNF-alpha mRNA expression in tissues. Similar results were also obtained between CD14, TNF-alpha mRNA expression in liver tissue and liver function parameters, and between pulmonary TNF-alpha mRNA and myeloperoxidase activities (p < 0.01).

CONCLUSION

Thermal injury per se can markedly up-regulate both LBP and CD14 gene expression in various organs. Excessive LBP and CD14 mRNA expression might be associated with enhanced synthesis and release of TNF-alpha stimulated by endotoxin translocation after major burns.

The role of endotoxin, TNF-α, and IL-6 in inducing the state of growth hormone insensitivity

AIM: Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-α, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-α and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS: Spague-Dawley rats were injected with endotoxin, TNF-α, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and β-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-α and IL-6 were detected by ELISA.

RESULTS: There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12 h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8 h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-α and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-α iv injection and had a 40% decrease at 8 h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION: The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-α and IL-6 indirectly, and TNF-α and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

The role of endotoxin, TNF-alpha, and IL-6 in inducing the state of growth hormone insensitivity

AIM

Critical illnesses such as sepsis, trauma, and burns cause a growth hormone insensitivity, which leads to an increased negative nitrogen balance. Endotoxin is generously released into blood under these conditions and stimulates the production of proinflammatory cytokines such as TNF-alpha, IL-6, and IL-1, which may play a very important role in inducing the growth hormone insensitivity. The objective of this current study was to investigate the role of endotoxin, TNF-alpha and IL-6 in inducing the growth hormone insensitivity at the receptor and post-receptor levels.

METHODS

Spague-Dawley rats were injected with endotoxin, TNF-alpha, and IL-6, respectively and part of rats injected with endotoxin was treated with exogenous somatotropin simultaneously. All rats were killed at different time points. The expression of IGF-I, GHR, SOCS-3 and beta-actin mRNA in the liver was detected by RT-PCR and the GH levels were measured by radioimmunoassay, the levels of TNF-alpha and IL-6 were detected by ELISA.

RESULTS

There was no significant difference in serous GH levels between experimental group and control rats after endotoxin injection, however, liver IGF-I mRNA expression had been obviously down-regulated in endotoxemic rats. Liver GHR mRNA expression also had a predominant down-regulation after endotoxin injection. The lowest regulation of liver IGF-I mRNA expression occurred at 12h after LPS injection, being decreased by 53% compared with control rats. For GHR mRNA expression, the lowest expression occurred at 8h and had a 81% decrease. Although SOCS-3 mRNA was weakly expressed in control rats, it was strongly up-regulated after LPS injection and had a 7.84 times increase compared with control rats. Exogenous GH could enhance IGF-I mRNA expression in control rats, but it did fail to prevent the decline in IGF-I mRNA expression in endotoxemic rats. Endotoxin stimulated the production of TNF-alpha and IL-6, and the elevated IL-6 levels was shown a positive correlation with increased SOCS-3 mRNA expression. The liver GHR mRNA expression was obviously down-regulated after TNF-alpha iv injection and had a 40% decrease at 8h, but the liver SOCS-3 mRNA expression was the 4.94 times up-regulation occurred at 40 min after IL-6 injection.

CONCLUSION

The growth hormone insensitivity could be induced by LPS injection, which was associated with down-regulated GHR mRNA expression at receptor level and with up-regulated SOCS-3 mRNA expression at post-receptor level. The in vivo biological activities of LPS were mediated by TNF-alpha and IL-6 indirectly, and TNF-alpha and IL-6 may exert their effects on the receptor and post-receptor levels respectively.

Six at six: interleukin-6 measured 6 h after the initiation of sepsis predicts mortality over 3 days

Virtually of the all recent therapeutic interventions for treating sepsis have failed to improve survival. One potential explanation is that the heterogeneity of the immune response to the septic challenge is such that only a portion of the patients die as a result of excessive inflammation. The clinical trials lacked power because traditional measurements do not accurately identify these patients. Previous work has shown that higher levels of interleukin (IL)-6 are found in those mice that die from septic peritonitis; therefore, we sought to determine whether IL-6 measured 6 h after surgery could predict outcome. Adult, female BALB/c mice (n = 79) were subjected to cecal ligation and puncture with a 21-gauge needle and treated with imipenem in D5W every 12 h for 5 days, resulting in a homogenous population at the outset. Six hours after surgery, 20 microL of blood was obtained from the tail vein to measure IL-6. Mortality was followed for 21 days. Overall 3-day survival was 77%, and 21-day mortality was 56%. Plasma IL-6 levels >2,000 pg/mL were determined to predict mortality within the first 3 days with a sensitivity of 58% and specificity of 97%. To further refine the mortality prediction, body weight and a complete blood count were performed 24 hours after cecal ligation and puncture. Discriminate analysis indicated that a weighted formula combining body mass, lymphocyte, and platelet count would predict death with sensitivity of 83% and a specificity of 79%. We tested the value of the IL-6 prediction by surgically resecting the cecum in those animals with IL-6 > 2000 pg/mL, which resulted in a significant improvement in survival. These data demonstrate that IL-6 measured 6 h after injury accurately predicts mortality resulting from experimental sepsis. This measurement may be determined quickly so that therapy may be targeted only to those individuals at significant risk of dying and initiated within sufficient time to be effective.