Lipopolysaccharide stimulates norepinephrine efflux from the rat hypothalamus in vitro: blockade by soluble IL-1 receptor

Lipopolysaccharide (LPS) has been shown to produce a number of central and neuroendocrine effects. While all mechanisms are not clear, it is believed that central catecholamines could be involved in this process. This study was done to investigate the direct effects of LPS on norepinephrine (NE) efflux from the medial basal hypothalamus in adult male rats using a combination of an in vitro incubation system and high performance liquid chromatography with electrochemical detection. Basal NE efflux was determined by incubating the hypothalami with Krebs Ringers Henseleit (KRH) alone for 60 min. Then, the hypothalami were incubated with KRH alone (control) or KRH containing 100 ng or 200 ng of LPS, 15 microg of soluble IL-1 receptor (sIL-1R) or a combination of 200 ng LPS and 5 or 15 microg of sIL-1R. In the third incubation period, the hypothalami were incubated with KRH alone to check for the residual effects of LPS if any. In the fourth incubation period, the hypothalami were incubated with high K+KRH to check for tissue viability. Incubation with LPS stimulated NE efflux in a dose-dependent manner. Incubation of hypothalami with 200 ng of LPS and 15 microg of sIL-1R completely blocked LPS-induced increase in NE efflux. These results indicate that LPS could act directly on the hypothalamus to stimulate the efflux of NE and this effect is probably mediated through IL-1.

Strain-dependent difference in inducible nitric oxide synthesis (iNOS) expression in rat pancreatic islets correlates with interferon regulating factor 1 (IRF-1) and heat shock protein 70 (HSP70) expression

Nitric oxide (NO) may be a necessary but not sufficient mediator of cytokine-mediated, selective beta-cell destruction. Previously, we have described a difference in NO-dependent IL-1beta sensitivity in vivo and in vitro of pancreatic islets from two rat strains, Brown Norway (BN) and Wistar Kyoto (WK), the latter being the more sensitive strain. Here we investigated whether strain-dependent, differential islet iNOS expression was associated with differences in islet expression of the IL-1 receptor type 1(IL-1RI) or interferon regulating factor 1 (IRF-1), and/or caused differences in HSP70 expression, a marker of cell defence against oxidative stress.

METHODS

isolated islets from both rat strains were exposed to increasing concentrations of IL-1beta (0-150 pg/ml) for 24 hours or for varying culture periods (4-48 hours) to 15 pg/ml of IL-1beta.

MEASUREMENTS

accumulated insulin and nitrite release into incubation medium, and islet mRNA and protein expression of iNOS, IL-1RI, IRF-1 and HSP70 by semi-quantitative RT-PCR and Western blotting.

RESULTS

Higher insulin and lower nitrite release into the incubation medium were seen for BN compared to WK rats islets in both dose- and time-response experiments. IRF-1 expression preceded iNOS expression and was more pronounced in WK than in BN islets. No strain differences were observed for islet expression of IL-1RI. A strain-dependent HSP70 expression in response to IL-1beta with the highest levels in WK rat islets following iNOS expression was seen.

CONCLUSION

There was a strain-dependent difference in iNOS expression which was associated with IRF-1 and HSP70 expression.

Down regulation of interleukin 1beta production in human osteoarthritic synovial tissue and cartilage cultures by aminoguanidine

OBJECTIVE

To evaluate the effect of aminoguanidine (AG) on de novo interleukin 1beta (IL1beta), nitric oxide (NO), and interleukin 1 receptor antagonist (IL1ra) production by osteoarthritic human synovial tissue and articular cartilage cultures.

METHODS

Synovial tissue and cartilage, obtained during surgery from 29 patients undergoing total knee or hip replacement for osteoarthritis, were cut into small pieces and cultured in the presence or absence of lipopolysaccharide (LPS) and test materials. IL1beta, IL1ra, and NO were determined in culture media. The inducible nitric oxide synthase inhibitor, AG, was added to cultures in various concentrations (0.3-3 mmol/l).

RESULTS

In synovial tissue cultures AG (0.3, 1, and 3 mmol/l) decreased LPS (1 microg/ml) stimulated IL1beta and NO release in the media in a dose dependent manner (p<0.05 at 1 mmol/l and p<0.05 at 0.3 mmol/l, respectively). In articular cartilage cultures AG (0.3, 1, and 3 mmol/l) decreased LPS (1 microg/ml) stimulated IL1beta and NO release in the media in a dose dependent manner (p<0.05 at 1 mmol/l and p<0.01 at 0.3 mmol/l, respectively). Hydrocortisone (5 microg/ml) also significantly decreased LPS stimulated IL1beta release in media of synovial tissue and cartilage cultures and NO in media of synovial cultures. AG (0.3, 1, and 3 mmol/l) decreased LPS (1 microg/ml) stimulated IL1ra levels in media of synovial tissue cultures in a dose dependent manner (p<0.05 at 1 mmol/l) but increased LPS (1 microg/ml) stimulated IL1ra release in media of cartilage cultures (p<0.01 at 3 mmol/l). The NO donor, nitroprusside (10, 30, 100, and 300 microg/ml) stimulated IL1beta release in media of synovial tissue cultures in a dose dependent manner (p<0.01 at 100 microg/ml). AG and nitroprusside at the concentrations used had no toxic effect on human synovial cells.

CONCLUSIONS

NO synthase inhibitors may modulate osteoarthritis and articular inflammatory processes not only by decreasing NO synthesis but also by their effects on ILbeta and IL1ra production.

The role of cytokines in physiological sleep regulation

Several growth factors (GFs) are implicated in sleep regulation. It is posited that these GFs are produced in response to neural activity and affect input-output relationships within the neural circuits where they are produced, thereby inducing a local state shift. These GFs also influence synaptic efficacy. All the GFs currently identified as sleep regulatory substances are also implicated in synaptic plasticity. Among these substances, the most extensively studied for their role in sleep regulation are interleukin-1beta (IL-1) and tumor necrosis factor alpha (TNF). Injection of IL-1 or TNF enhances non-rapid eye movement sleep (NREMS). Inhibition of either IL-1 or TNF inhibits spontaneous sleep and the sleep rebound that occurs after sleep deprivation. Stimulation of the endogenous production of IL-1 and TNF enhances NREMS. Brain levels of IL-1 and TNF correlate with sleep propensity; for example, after sleep deprivation, their levels increase. IL-1 and TNF are part of a complex biochemical cascade regulating sleep. Downstream events include nitric oxide, growth hormone releasing hormone, nerve growth factor, nuclear factor kappa B, and possibly adenosine and prostaglandins. Endogenous substances moderating the effects of IL-1 and TNF include anti-inflammatory cytokines such as IL-4, IL-10, and IL-13. Clinical conditions altering IL-1 or TNF activity are associated with changes in sleep, for example, infectious disease and sleep apnea. As our knowledge of the biochemical regulation of sleep progresses, our understanding of sleep function and of many clinical conditions will improve.

Physiological significance of the interleukin 1 receptor accessory protein

Interleukin 1 receptor accessory protein (IL-1RAcP) is an essential signal-transducing component of the IL-1 receptor type I. The recent availability of IL-1RAcP-deficient (KO) mice allows to study the in vivo function of IL-1RAcP. Animals were injected intraperitoneally with rat recombinant IL-1beta (200 ng/mouse), lipopolysaccharide (LPS, 5 microg/mouse), or subjected to 1-hour restraint stress. Neuroendocrine and immune parameters were measured 2 h after IL-1 or LPS injection or just after restraint. In wild-type controls, IL-1 and LPS activated the hypothalamic-pituitary-adrenal axis and increased plasma IL-6. In KO mice, the plasma levels of corticosterone and IL-6 increased after LPS, but not after rat recombinant IL-1beta. The LPS-induced depression of the lymphoproliferation was similar in wild-type and KO mice. Finally, the 1-hour restraint was able to increase the plasma levels of corticosterone in KO mice. These results show that IL-1RAcP is essential for physiological activities of peripheral IL-1, as it was previously demonstrated for those of brain IL-1. However, using IL-1RAcP KO mice, we were unable to demonstrate a specific role of endogenous IL-1 during LPS-induced inflammation. Moreover, stress-induced activation of the hypothalamic-pituitary-adrenal axis may occur in the absence of the IL-1-transducing receptor, IL-1RAcP.

Clostridium difficile toxin: cytoskeletal changes and lactate dehydrogenase release in hepatocytes

BACKGROUND

We have found that Clostridium difficile toxins can evoke hepatocyte acute-phase protein synthesis, and that this effect is dependent on a functioning interleukin-1 (IL-1) receptor. The present study was undertaken to determine if C. difficile toxicity, as determined by actin rearrangement and lactate dehydrogenase (LDH) release, also requires a functioning IL-1 receptor.

METHODS

Primary hepatocyte cultures were prepared from normal mice, knockout mice deficient in the IL-1-converting enzyme (ICE), and knockout mice deficient in the IL-1 p80 receptor. Hepatocytes were treated for 24 h with C. difficile culture extract, purified C. difficile toxin A, or purified C. difficile toxin B. The actin cytoskeleton was examined using confocal microscopy, and LDH release was measured by spectrophotometric analysis.

RESULTS

C. difficile culture extract, toxin A, and toxin B induced collapse of the actin cytoskeleton in hepatocytes from normal mice. Hepatocytes from both the ICE-deficient mice and the IL-1 p80 receptor-deficient mice demonstrated similar responses to both toxins. These toxins also induced significant LDH release in a concentration-dependent fashion in the normal hepatocytes and the ICE-deficient hepatocytes. However, no significant increase in LDH release was observed in hepatocytes from IL-1 p80 receptor-deficient mice.

CONCLUSIONS

C. difficile toxins induce actin cytoskeletal collapse independent of IL-1 or the IL-1 receptor. In contrast, toxin-stimulated LDH release was dependent on the presence of the IL-1 receptor. Thus, separate pathways appear to mediate toxic effects as manifested by actin rearrangement and LDH release.

Aspirin-induced increases in soluble IL-1 receptor type II concentrations in vitro and in vivo

This study examined the influence of low-dose aspirin on interleukin (IL)-1alpha , IL-1 receptor antagonist (IL-1ra), and soluble receptor type II (sIL-1RII) secretion in vivo and in vitro. Blood mononuclear cells were isolated from healthy young men who ingested 81 mg of aspirin on alternate days for 2 weeks and from unmedicated controls. Aspirin had minor effects on ex vivo secretion of IL-1beta and no influence on IL-1ra. In contrast, unstimulated ex vivo secretion of sIL-1RII was over twice as high by cells from aspirin-treated subjects (1115+/-123 vs. 460+/-77 pg/mL, P = 0.02). Lipopolysaccharide-stimulated sIL-1RII secretion was influenced similarly. Plasma sIL-1RII concentrations were 23% higher in aspirin-treated subjects (10.2+/-0.6 vs. 8.4+/-0.3 ng/mL, P = 0.03). In addition, cells from unmedicated subjects cultured in vitro with aspirin (10 microg/mL) secreted significantly greater amounts of sIL-1RII. Thus, low-dose aspirin therapy may prevent inflammation by increasing soluble receptor secretion, thereby preventing IL-1 from binding target cells.

Dexamethasone regulation of interleukin-1-receptors in the hippocampus of Theiler's virus-infected mice: effects on virus-mediated demyelination

Intracerebral (i.c.) inoculation of susceptible strains of mice with Theiler's murine encephalomyelitis virus (TMEV) results in immune-mediated demyelinating disease. Interleukin-1 receptors are expressed in the brain of mice, in particular in the hippocampus, and have been implicated in neuroimmunoendocrine interactions. In the present study we investigated the regulation of interleukin-1 receptors in the hippocampus of a susceptible (SJL/J) and a resistant (BALB/c) strain of mice infected with TMEV, at different time intervals of the disease. Our results show that interleukin-1 receptors in the hippocampus were decreased in TMEV-infected mice at early times post-infection (10 and 14 days p.i.). The reduction in interleukin-1 receptors only occurred in the susceptible strain of mice (SJL/J), whereas interleukin-1 binding in the hippocampus of TMEV-infected resistant mice (BALB/c) showed values similar to those in control animals. The TMEV-induced down-regulation of interleukin-1 receptors was secondary to a marked decrease in the affinity of the receptor (control: Kd = 10.5 pM; TMEV: Kd = 1.30 pM) accompanied by a decrease in receptor number (control: Bmax = 2.189 fmol/mg protein; TMEV: B max = 0.84 fmol/mg protein). We also investigated the effects of glucocorticoid treatment on the regulation of hippocampal interleukin-1 receptors of TMEV-infected mice. Dexamethasone treatment in the early phase (500 microg/kg or 1 mg/kg during days 5-10 p.i.) of the disease significantly reversed the deficits in hippocampal interleukin-1 receptors observed at 10 days p.i. in SJL/J mice, and suppressed neurological signs of demyelination. These results suggest that: (i) the reduction of interleukin-1 receptors may be a consequence, at least in part, of local production of interleukin-1 at early times during TMEV infection; (ii) interleukin-1 seems to be a critical factor for the susceptibility to TMEV-induced demyelination and (iii) the protective effect of dexamethasone appears to be related to its ability to reverse the reduction in interleukin-1 receptors during the early disease. These results suggest that interleukin-1 is a pivotal mediator in TMEV-induced demyelination.

Interleukin-1 alpha induced cyclooxygenase-2 expression in bone-derived endothelial cells

Histological studies have suggested that vascular endothelial cells in bone are members of a complex network that regulates bone development and remodeling by producing soluble factors or by mediating cell-cell adhesion. To clarify the role of bone-derived endothelial cell lines (BDECs) in bone remodeling, we established several clones of BDECs from the femurs of BALB/c mice after transformation with the SV40 virus. Then we examined the response of these clones to interleukin-1alpha (IL-1alpha). IL-1alpha is known to induce bone resorption in part by increasing the expression of cyclooxygenase-2 (COX-2) that is associated with the production of PGE2 in osteoblast-lineage cells. Treating the primary and established BDECs with IL-1alpha induced COX-2 mRNA expression. A transcriptional activation assay revealed that the treatment with IL-1alpha increased COX-2 promoter activity in a dose-dependent manner, and IL-1alpha promoted COX-2 protein expression in BDECs. Treatment with IL-1alpha promoted PGE2 production from BDECs in a dose-dependent manner. These results indicate that IL-1alpha stimulates PGE2 synthesis largely by inducing BDECs to express COX-2. Because PGE2 stimulates bone resorption, these vascular endothelial cells, as well as osteoblast cells, play important roles in bone remodeling.

Interleukin-1 signaling is dependent on free thiols

Stimulation of the Interleukin-1 receptor type I (IL-1-RI) with IL-1 activates an associated serine/threonine kinase, IRAK, which phosphorylates downstream targets, resulting in NFkappaB activation. The signaling cascade is accompanied by oxidative processes and contains putative targets for redox regulation. Preincubation of the murine T cell line EL-4 and the human umbilical cord vein endothelial cell line ECV 304 with thiol modifying compounds like diamide, menadione or phenylarsine oxide inhibited the IL-1-induced phosphorylation of an endogenous substrate with a molecular mass of 60 kD. In the endothelial cell line, a second target of about 85 kD was phosphorylated after IL-1 stimulation, which was also inhibited by thiol modification. These data suggest that IL-1 signal transduction depends on free thiols which might be targets for redox regulation not only in lymphocytes, but also in endothelial cells.

Interleukin-1 receptor defect in autoimmune NZB mouse brain

Interleukin-1 receptors (IL-1R type I and II) have been characterized in murine nervous structures (hippocampus and frontal cortex), in vascular structures (vessels, choroid plexus), and in the anterior pituitary. Because interleukin-1 (IL-1), injected or induced in the brain, is a powerful regulator of the stress axis and immune functions, it was of interest to investigate IL-1Rs and IL-1 in autoimmune mice. In control mice, bacterial lipopolysaccharide (LPS), administered i.p. or i.c.v., induces a sharp decrease in available brain IL-1 receptors, in spite of a moderate increase in mRNAs for both receptor types. This is concomitant with an increase in IL-1 alpha, beta, and ra mRNA. Ligand production clearly overcomes receptor turnover. In autoimmune mice (NZB and NZB/NZW F1), a strong defect in IL-1R (type I) is demonstrated in the dentate gyrus. This tissue-specific defect cannot be explained by increased occupancy by endogeneous ligands as for LPS-treated mice. The transmission of the defect is Mendelian and suggests the involvement of a single gene. However patterns of IL-1R mRNAs (evaluated by RT-PCR) are similar in NZB and in controls, suggesting a translational or post-translational abnormality. The contribution of this genetic disorder in the development of autoimmunity remains to be clarified. Because the brain IL-1 system sends inhibitory signals towards immune functions, this lack of functional IL-1 binding sites might participate in the disregulations observed in NZB autoimmune mice.

Correlation of serum levels of interleukin-1 family members with disease activity and response to treatment in hairy cell leukemia

Hairy cell leukemia (HCL) is a well-recognized chronic lymphoproliferative disorder of B cell lineage, which may be regulated by growth factors including cytokines and cytokine antagonists. Previous studies have shown a good correlation between circulating soluble interleukin-2 receptor (sIL-2R) levels and disease activity and response to therapy was always associated with a decrease in sIL-2R levels. The interleukin-1 (IL-1) family of agonists and antagonists may also be involved in the regulation of hematopoietic malignancies. In the present study, we evaluated members of the IL-1 family (IL-1beta, IL-1 receptor antagonist (IL-1Ra) and IL-1 soluble receptors Type I and Type II (IL-1sRI and IL-1sRII) in 23 patients with HCL. Patients were classified according to the clinical state of their disease. Most were treated with 2-chloro-2'-deoxyadercosine (2-CDA) and treatment was associated with a significant decrease in the serum levels of sIL-2R, IL-1beta and IL-1sRII in patients achieving a complete or partial response. In contrast to the above, levels of IL-1Ra increased during response to treatment and clinical response to 2-CDA was associated with an increase of 122% in IL-1Ra levels, in parallel with a decrease of 63% in IL-1beta and 47% in IL-1sRII levels. These results suggest that the balance between IL-1beta, IL-2 and their soluble receptors or antagonists may be involved in the pathogenesis and immunoregulation of HCL. Serum levels of these cytokines may therefore be used to monitor therapeutic efficacy of therapy in HCL and to detect any residual disease.

Insulin-like growth factor I affects the intraovarian interleukin-1 system: evidence for suppression of type I interleukin-1 receptor expression and enhancement of secretory phospholipase A2 expression and activity

This study assessed the possibility that the intraovarian insulin-like growth factor I (IGF-I) system interacts with the intraovarian interleukin-1 (IL-1) system, the central role of which has been the subject of increasing attention. To this end, whole ovarian dispersates from immature rats were cultured for 48 h in the absence or presence of IGF-I or IGF-binding protein-3 (IGFBP-3), with or without IL-1beta. Cellular RNA content was subjected to a solution hybridization, RNase protection assay with gel-purified [32P]-UTP-labelled antisense riboprobes for rat IL-1beta, type I IL-1 receptor (IL-1R) and secretory phospholipase A2 (sPLA2). PLA2 activity in conditioned media was assayed by measuring the release of [3H]-labelled palmitic acid from the sn-2 position of [3H]-labelled phosphatidylcholine dipalmitoyl (PCDP) substrate. Treatment with IGF-I resulted in a significant (P< 0.01) decrease in type I IL-1R transcripts (an effect which was reversed by co-treatment with IL-1beta), was without effect on IL-1beta transcripts, and significantly (P < 0.05) increased sPLA2 gene expression (an effect which was further enhanced by co-treatment with IL-1beta). Treatment with IGF-I resulted in a significant increase in extracellular PLA2 activity over untreated control. These observations suggest that IGF-I may down-regulate ovarian IL-1 action by decreasing type I IL-1R gene expression, while up-regulating sPLA2 gene expression and activity. These findings are consistent with a role for IGF-I in suppressing IL-1 actions while promoting the generation of prostaglandins. It is tempting to speculate that IGF-I, an intraovarian regulator concerned with promoting folliculogenesis, may be also entwined with priming the prostaglandin-producing potential in anticipation of subsequent ovulation.

Interleukin-1 (IL-1) receptor type I mediates anorexia but not adipsia induced by centrally administered IL-1beta

IL-1beta induces anorexia and adipsia. Here, we report that intracerebroventricular (ICV) pretreatment with an antisense (but not sense) phosphothio-oligodeoxynucleotide to the IL-1 receptor type I (IL-1RI, 1.28 microg or 239 pmol twice daily for 3.5 days before IL-1beta plus antisense) inhibits the anorexia, but not the adipsia induced by the ICV administration of 2.0 ng IL-1beta/rat (a dose that yields estimated pathophysiological concentrations in the cerebrospinal fluid). The mean 2 h food intake decrease in response to IL-1beta was 5.6% (n = 10) in the antisense- and 43% in the sense (n = 9)-treated groups; the mean 2 h water intake decrease was 40% in the antisense- and 39% in the sense-treated groups. The intraperitoneal administration of IL-1RI antisense, in doses equivalent to those administered centrally, had no effect on the anorexic effect induced by ICV administered IL-1beta; this indicates a direct action in the central nervous system. The results suggest that: i) IL-1RI is involved in the short-term anorexigenic, but not the adipsogenic effect induced by centrally administered IL-1beta; and ii) the approach presented using antisense strategies is applicable to study the molecular basis of IL-1 mediated behaviors.

In vivo immunomodulatory effects of clozapine in schizophrenia

Recently, there have been some reports that schizophrenia is accompanied by an immune-inflammatory response, characterized by increased secretion of interleukin-6 (IL-6), soluble IL-2 receptor (sIL-2) and lower plasma levels of CC16 (Clara cell protein), an endogenous anti-cytokine. It was shown that clozapine, an atypical antipsychotic drug, may increase the plasma levels of sIL-2R and pro-inflammatory cytokines. This study was carried out in order to examine serum IL-6, IL-6R, CC16, IL-1R antagonist (IL-1RA), transferrin receptor (TfR) and sCD8 antigen, both before and after treatment with clozapine in schizophrenic subjects versus normal controls. Schizophrenic patients showed significantly higher plasma IL-6R and IL-1RA and lower plasma CC16 than normal controls. Treatment with clozapine significantly increased plasma sCD8, IL-6, CC16 and IL-1RA concentrations. The clozapine-induced increments in plasma IL-6 and CC16 appeared during the first 2 weeks of treatment, whereas the increases in plasma sCD8 and IL-1RA appeared after 5 weeks. Clozapine appears to have complex in vivo immunomodulatory effects.

Receptor induction regulates the synergistic effects of substance P with IL-1 and platelet-derived growth factor on the proliferation of bone marrow fibroblasts

The neuropeptide substance P (SP) stimulates CFU in bone marrow (BM) cultures. Although the methylcellulose matrix used in these assays does not provide an appropriate substratum to support adherent-dependent cells, we have observed that cultures containing optimal SP (10(-8)-10(-10) M) develop confluent areas of reticular/fibroblastoid-like cells with CFUs predominantly localized within their vicinity. Characterization (cytochemical and immunofluorescence) of the reticular/fibroblastoid-like cells indicated that they were fibroblasts, the major constituent of the BM stroma. Hemopoietic effects by SP are mediated by the stroma that expresses SP receptors. We studied the effects of SP (10(-7)-10(-11) M) with suboptimal platelet-derived growth factor-BB (PDGF-BB; 5 ng/ml) and IL-1alpha (2 ng/ml), two fibrogenic cytokines, and also hemopoietic regulators. SP by itself and in synergy with either cytokine induced fibroblast proliferation. At optimum SP, IL-1alpha induced 1.6 times the proliferation of PDGF-BB (87 +/- 7 vs 55 +/- 5; n = 12; p < 0.05). The effects of SP were blunted by a specific neurokinin-1 antagonist. Scatchard analysis indicated that SP binds to BM fibroblasts with an approximate Kd of 5 nM. SP induced steady state mRNA for IL-1 receptor IL-1RI and PDGF-BB (PDGF-AR, PDGF-BR) receptors by 7.5-, 6.2-, and 10.5-fold, respectively. Their up-regulation may be partly responsible for the synergistic effects of SP and their ligands. Induction (3-fold) of neurokinin-1 mRNA by IL-1alpha compared with no induction by PDGF-BB may explain the preferred synergism between SP and IL-1alpha. This study indicates that induction of SP, IL-1alpha, and PDGF-BB receptors is important to their synergistic effects on BM fibroblast proliferation. These results bring new insights into stroma-mediated hemopoietic regulation.

The afferent discharges from sensors for interleukin 1 beta in the hepatoportal system in the anesthetized rat

The effect of intraportal administrations of interleukin 1 beta (IL-1 beta) on the afferent activity of the hepatic branch of the vagus nerve was observed in urethane anesthetized rats. An intraportal injection of IL-1 beta in doses of 10 pg and 100 pg per animal (300-400 g body wt.) resulted in dose-dependent increase in the afferent activity, which lasted about 70-100 min. Further, intraportal injection of IL-1 beta (100 pg) induced reflex activation of efferent activity of the splenic (sympathetic) nerve and vagal thymic nerve. This reflex activation was not observed in hepatic vagotomized rat and after an administration of the same dose of IL-1 beta into the systemic vein in normal rat. The results suggest the existence of sensors for IL-1 beta which send information on IL-1 beta in the portal venous blood to the central nervous system through the hepatic branch of the vagus nerve and play some role in reflex regulation of immune function.

An approach to study molecular mechanisms involved in cytokine-induced anorexia

Cytokines are released during pathophysiological processes. Cytokines (e.g., interleukin-1 beta or IL-1 beta) induce neurological manifestations including anorexia. Here, we show an integrative approach to investigate the cellular and molecular basis of cytokine-induced anorexia. In this approach: (1) the chronic intracerebroventricular (icv) microinfusion (via osmotic minipumps) of cytokines, at doses that will yield estimated pathophysiological concentrations reported in the cerebrospinal fluid, is used. (2) General and computerized behavioral monitoring characterizes the microstructure of behavioral modifications induced by a cytokine, and the time course for cytokine action. (3) Brain regions and subregions (nuclei/areas) from animals exhibiting significant anorexia in response to cytokine(s) are dissected, and RNA and protein are isolated. (4) The profile of cytokine subsystems (ligands, receptors, endogenous inhibitors; for example, IL-1 alpha and beta, IL-1 receptor types I and II, and IL-1 receptor antagonist) is characterized in the same brain samples with polymerase chain reaction, sensitive RNase protection assays and immunoblots. (5) The relationship between changes in cytokine subsystems at the molecular level and cytokine-induced anorexia within an animal is determined, and the general profile is analyzed with statistical methods. This approach is also pertinent to study neurotransmitter and neuropeptide profiles, and cytokine-cytokine, cytokine-neuropeptide and cytokine-neurotransmitter interactions in vivo. The results show that this integrative and novel strategy can be used to study the molecular basis of anorexia and other neurological manifestations (e.g., fever, sleep changes) induced by cytokines.

Hormonal regulation of serum and endometrial IL-1 alpha, IL-1 beta and IL-1ra: IL-1 endometrial microenvironment of the human embryo at the apposition phase under physiological and supraphysiological steroid level conditions

We have investigated serum and intracavitary levels of IL-1 alpha, IL-1 beta and IL-1ra from agonadal women undergoing mock cycles (n = 20) of oocyte donation as a clinical model of controlled hormonal stimulation. Further, we compared the intracavitary IL-1 alpha, IL-1 beta and IL-1ra levels in the microenvironment of the human embryo at the apposition phase, day 5 after progesterone (P) administration using two different clinical models: oocyte donation (n = 20) which provides physiological steroid levels and a higher implantation rate per embryo, and in vitro fertilization (n = 6) with supraphysiological hormonal levels and a lower implantation rate.

[Acute pancreatitis: inflammatory response of the body]

The author reviews the most important data related with the pathogenesis of pancreatitis acuta, the pathological characteristics, the clinical development of the disease, the more frequent complications are summarized. Within this scope the evolutionary mechanisms of the organ damages are discussed, the diagnostic and prognostic relations are delineated, too. Particular attention is paid to the development and regulation of the defending, preventing reactions of the organisms connected with pancreatitis acuta. The process of leukocyte emigration into the tissue being shortly summarized, the acute phase reaction of the organism and the pathophysiological, clinical significance of the acute phase reactants are likewise presented. The author deals distinctly with the physiological, pathophysiological functions of alpha 2-macroglobulin and with its significance in pancreatitis acuta. The therapeutic outlooks are in a few words touched upon. The acute phase reaction of the organism is inserted in the framework of the possible types of the protecting, preventing responses of the organism.

Interleukin-1 receptor accessory protein transcripts in the brain and spleen: kinetics after peripheral administration of bacterial lipopolysaccharide in mice

Receptors for IL-1, type I (IL-1R1) and type II (IL-1R2), have been characterized by pharmacological and molecular techniques in the mouse brain. High densities are mainly found in the cortex, dentate gyrus and choroid plexus. It was therefore of interest to investigate the expression of mRNA IL-1 receptor accessory protein (IL-1R AcP), which is a part of the IL-1 receptor complex and has been shown to interact specifically with IL-1R1. IL-1R AcP transcripts were detected under basal conditions following RT-PCR amplification in the mouse brain, as well as in the pituitary, spleen, adrenal and liver. IL-1R AcP transcripts were found in higher amounts than IL-1R1 transcripts in all tissues except the spleen, where their expression was minor. Following bacterial lipopolysaccharide (LPS) stimulation (3-48 h), IL-1R AcP transcripts were not changed in the brain, while IL-1R1 transcripts were increased for 3-6 h. In the spleen, a slight increase in IL-1R AcP and IL-1R1 was observed during the first hours following LPS stimulation. In conclusion, IL-1R AcP mRNA is expressed in the brain and in other tissues where IL-1R1 transcripts are found. However, the regulation of its expression is distinct from IL-1R1. The high level of expression and the lack of regulation of IL-1R AcP transcripts in the brain under inflammatory conditions suggest that the protein might be constitutively expressed in excess.

An investigation of the effects of heparin, low molecular weight heparin, protamine, and fentanyl on the balance of pro- and anti-inflammatory cytokines in in-vitro monocyte cultures

We report a study conducted to determine if drugs given peri-operatively during cardiac surgery could themselves modulate the balance of pro- and anti-inflammatory cytokines. We determined the cytokine response of 10 separate in vitro monocyte cultures to the administration of drugs at concentrations used during cardiac 'surgery:fentanyl (25 ng.ml-1), heparin 2.5 i.u.ml-1, heparin with an equal concentration of protamine, and enoxaparin 2.5 i.u.ml-1. Fentanyl, heparin and low molecular weight heparin (enoxaparin) led to increased tumour necrosis factor alpha but this did not reach statistical significance. Tumour necrosis factor soluble receptor 1 and 2 was not elevated. Interleukin-1 beta was increased by heparin (p < 0.05), whereas interleukin-1 receptor antagonist was increased by fentanyl (p < 0.05). Protamine blocked the heparin-induced increase in tumour necrosis factor alpha and interleukin-1 beta. These data raise the possibility that endogenous and exogenously administered opioids may be partly contributing to the interleukin-1 receptor antagonist response seen during major surgery.

Detection and in vivo hormonal regulation of rat ovarian type I and type II interleukin-I receptor mRNAs: increased expression during the periovulatory period

OBJECTIVE

To study the expression, localization, and in vivo hormonal regulation of type I and type II interleukin-1 (IL-1) receptors in the rat ovary.

METHODS

Segments of the cDNAs for rat type I and type II IL-1 receptors were cloned and used as probes in RNase protection assays and in situ hybridization. Tissues obtained from immature rats and hormonally treated rat ovaries were examined.

RESULTS

Type I IL-1 receptor (IL-1R(1)) was ubiquitously expressed in rat tissues, including granulosa cells prepared from immature ovaries, whereas type II IL-1 receptor (IL-1R(2)) expression was restricted to macrophages, thymus, and lung. Hypophysectomy and subsequent treatment with FSH and/or diethylstilbestrol did not alter significantly the abundance of IL-1R(1) transcripts in the whole ovary. However, the relative amount of ovarian IL-1R(1) transcripts increased 7.3-fold 6 hours after the administration of hCG to pregnant mare serum gonadotropin-primed immature rats. During this time, IL-1R(1) mRNA was localized primarily in the granulosa cells. The increased expression of IL-1R(1) persisted 24 hours after hCG administration but declined to baseline by 48 hours. Ovarian expression of IL-1R(2) mRNA was observed only before ovulation in amounts that were approximately 70-fold lower than IL-1R(1).

CONCLUSION

The increased intraovarian expression of IL-1R(1) in granulosa cells during the periovulatory period implies that this cell type has a heightened receptivity to IL-1 and provides further indirect evidence that this cytokine is involved in the ovulatory process.