Modulation of cytokine release and neutrophil function by granulocyte colony-stimulating factor during endotoxemia in humans

In this double-blind, cross-over, placebo-controlled, randomized study, two groups of eight healthy male volunteers were challenged with endotoxin (4 ng/kg) on two occasions, once in conjunction with placebo and once with granulocyte colony-stimulating factor (G-CSF; 5 microg/kg). In group 1, G-CSF was administered intravenously 2 hours before endotoxin challenge; in group 2, G-CSF was administered subcutaneously 24 hours before endotoxin challenge. In group 1, G-CSF significantly enhanced the release of tumor necrosis factor (TNF), interleukin-6 (IL-6), IL-8, IL-1 receptor antagonist (IL-1ra), and soluble TNF receptors. In group 2, G-CSF significantly reduced IL-8 concentrations and modestly attenuated TNF and IL-6 levels. In this group, IL-1ra and soluble TNF receptors were enhanced by G-CSF pretreatment and lipopolysaccharide (LPS)-induced soluble TNF receptor release was further augmented, whereas LPS-induced IL-1ra concentrations remained unaltered. Both pretreatments with G-CSF increased LPS-induced peripheral neutrophilia; the expression of CD11b, CD18, and CD67; and the release of elastase and lactoferrin. Both pretreatments also down-regulated neutrophil L-selectin expression and prevented the endotoxin-induced pulmonary neutrophil accumulation during the first 2 hours after endotoxin challenge. These data indicate that two different pretreatments with G-CSF result in differential effects on LPS-induced cytokine release but similar effects on LPS-induced neutrophil activation and changes in expression of cell surface molecules. Finally, regardless of the effects of G-CSF on LPS-induced cytokine release, G-CSF blocks LPS-induced pulmonary granulocyte accumulation.     

Foreign residency: specialist candidate in the United States

OBJECTIVE: Endotoxin as the inciting agent of cytokines and other mediators, whose high level expression correlates with the septic shock and MOF, has been the one of leading causes of death in ICU. METHODS: For treating sepsis and MOF caused by endotoxin, the anti-lipid A of LPS antibody was used, 19 burned patients whose TBSA varied from 50% to 100% were divided into anti-LPS treatment group and nontreated group. RESULTS: The levels of serum endotoxin, IL-6, IL-8, TNF and soluble IL-2R were lower obviously in patients of anti-LPS group than those of nontreated group (P < 0.05). CONCLUSION: Clinical study surggests that anti-lipid A of LPS antibody can act as an therapeutic agent against gram-negative bacterin infection in burned patients.     

Quantitative genetics of vector competence for dengue-2 virus in Aedes aegypti

OBJECTIVES: To determine whether endothelin-1 (ET-1) in tracheal aspirates (TA) is a specific marker for acute lung injury in preterm infants with respiratory distress syndrome (RDS) who progress to bronchopulmonary dysplasia (BPD); and to investigate the relationship between TA ET-1 and the proinflammatory cytokines, interleukin-6 (IL-6) and IL-8, as early mediators of BPD. STUDY DESIGN: We measured TA ET-1, IL-6, and IL-8 levels in preterm infants whose lungs were mechanically ventilated for RDS, categorized into two groups, BPD or non-BPD, on the basis of oxygen requirement at 36 weeks' postconceptional age. RESULTS: A total of 106 TA samples were obtained from 34 infants with gestational ages ranging from 24 to 28 weeks on days 1, 3, 5, and 7 of life. There was a wide range of ET-1 concentration. TA ET-1 levels were significantly elevated on days 1, 3, and 7 in infants in whom BPD developed, in comparison with the non-BPD group (Mann-Whitney U test: p < 0.01). TA IL-8 levels were elevated on days 1, 3, 5, and 7 in the BPD group (p < 0.01); TA IL-6 levels were elevated (p < 0.05) only on day 5. There was a similarity in pattern of increase of TA ET-1 and TA IL-8 levels in the BPD group, with both being elevated in the first 24 hours of life and through the first week. There was no correlation between ET-1 and IL-8 values. CONCLUSION: Early significant increase in the TA ET-1 and IL-8 concentrations in preterm infants with acute lung injury correlates with subsequent progression to BPD.     

Gut is not a source of cytokines in a porcine model of endotoxicosis

BACKGROUND: We sought to determine whether ischemic gut is a source of endotoxin, tumor necrosis factor (TNF), and interleukin-6 (IL-6) in a porcine model of endotoxicosis. METHODS: Under general anesthesia pigs underwent neck dissection and laparotomy for placement of catheters in the carotid artery and portal vein and application of an ultrasonic flow probe around the portal vein. Endotoxin, TNF, and IL-6 levels were measured from the carotid artery and the portal vein during a 4 hour period in animals given endotoxin (50 mg/kg; n = 6) and in animals in the control group (n = 6). Gut fluxes of the substances of interest were calculated as the product of concentration and portal venous flow. A tonometer placed in the terminal ileum was used to monitor mucosal pH. RESULTS: Small bowel mucosal pH was significantly depressed in endotoxemic animals (6.8 +/- 0.1) when compared with baseline (7.1 +/- 0.1; p < 0.05) and control levels. In the control group portal venous levels of endotoxin, TNF, and IL-6 did not change significantly from baseline levels (1.5 +/- 0.4 endotoxin units (EU)/ml, 24 +/- 3 pU/ml, and 1.3 +/- 0.4 nU/ml, respectively). In the endotoxemic animals portal venous endotoxin and TNF levels peaked immediately after the endotoxin infusion (2186 +/- 437 EU/ml, and 293 +/- 125 pU/ml, respectively), and portal venous IL-6 levels peaked at 180 minutes (168 +/- 21 nU/ml). At no time did endotoxin, TNF, or IL-6 levels differ between arterial and portal venous blood, and at no time did efflux from the gut significantly exceed gut influx in either the control or endotoxemic animals. CONCLUSIONS: Ischemic gut as indicated by decreased mucosal pH is not associated with gut release of endotoxin, IL-6, or TNF in this porcine model of endotoxicosis.     

Influence of heat shock protein 70 and metallothionein induction by zinc-bis-(DL-hydrogenaspartate) on the release of inflammatory mediators in a porcine model of recurrent endotoxemia

The manipulation of stress gene expression by heavy metals provides protection against the lethal effects of endotoxemia in murine models of septic shock. Recent in vitro studies with alveolar macrophages or monocytes show that induction of the stress response in these cells is followed by a decreased liberation of major cytokines [tumor necrosis factor-alpha (TNF alpha) and interleukin-1 (IL-1)] after endotoxin challenge. These findings suggest that the increased resistance to endotoxin in vivo after stress protein induction could be explained by an altered pattern of inflammatory mediator release. Therefore, we measured the time course of thromboxane-B2 (TxB2), 6-keto-PGF1 alpha, platelet activating factor (PAF), TNF alpha, interleukin-1 beta (IL-1 beta), and interleukin-6 (IL-6) formation with and without induction of the stress response in an established porcine model of recurrent endotoxemia (Klosterhalfen et al., Biochem Pharmacol 43: 2103-2109, 1992). Induction of the stress response was done by a pretreatment with Zn2+ (25 mg/kg zinc-bis-(DL-hydrogenasparate = 5 mg/kg Zn2+). Pretreatment with Zn2+ prior to lipopolysaccharide (LPS) infusion induced an increased heat shock protein 70 and metallothionein expression in the lungs, liver, and kidneys and increased plasma levels of TNF alpha, IL-1 beta, IL-6, and TxB2 as opposed to untreated controls. After LPS infusion, however, pretreated animals showed significantly decreased peak plasma levels of all mediators as opposed to the untreated group. The time course of mediator release was identical with the decreasing and increasing three peak profiles described previously. Hemodynamic data presented significantly decreased peak pulmonary artery pressures and significantly altered hypodynamic/hyperdynamic cardiac output levels in the pretreated group. In conclusion, the data show that the induction of stress proteins by Zn2+ could be a practicable strategy to prevent sepsis.     

Pattern of cytokines and pharmacomodulation in sepsis induced by cecal ligation and puncture compared with that induced by endotoxin

The production of tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and IL-6 and their pharmacomodulation were evaluated in a model of polymicrobial sepsis induced in mice by cecal ligation and puncture (CLP) and were compared with the effects of endotoxin (lipopolysaccharide [LPS]) treatment. LPS levels rose as early as 1 h after CLP and increased further after 2 and 21 h. TNF-alpha was detectable in serum, spleen, liver, and lungs during the first 4 h, with a peak 2 h after CLP. IL-1 beta was measurable in serum after 24 h, and levels increased significantly in spleen and liver 4 and 8 h after CLP. IL-6 levels increased significantly in serum throughout the first 16 h after CLP. These cytokines were detectable after LPS injection, with kinetics similar to those after CLP but at a significantly higher level. To cast more light on the differences between these two animal models of septic shock, we studied the effects of different reference drugs. Pretreatment with dexamethasone (DEX); ibuprofen (IBU), an inhibitor of cyclooxygenase; and NG-nitro-L-arginine, an inhibitor of nitric oxide synthase, significantly reduced survival, while chlorpromazine (CPZ) and TNF did not affect it. Only the antibiotics and pentoxifylline significantly increased survival in mice with CLP. However, CPZ and DEX protected the mice from LPS mortality. On inhibiting TNF-alpha with DEX, CPZ, or pentoxifylline, survival was reduced, unchanged, and increased, respectively, and on increasing TNF-alpha with IBU and TNF, survival was decreased or unchanged, respectively, suggesting that the modulation of this cytokine does not play a significant role in sepsis induced by CLP, unlike treatment with LPS. The negative effects of IBU and N(G)-nitro-L-arginine suggest a protective role by prostaglandins and nitric oxide in sepsis induced by CLP.     

A missense mutation in the human connexin50 gene (GJA8) underlies autosomal dominant "zonular pulverulent" cataract, on chromosome 1q

OBJECTIVE: To determine the effect of hemorrhagic shock on spontaneous and endotoxin-induced cytokine release from intestinal mononuclear cells compared with whole portal venous blood and splenic macrophages. DESIGN: Random assignment to either unmanipulated control group, sham operation group, or hemorrhagic shock group. SETTING: University animal laboratory. SUBJECTS: Male Wistar rats, weighing between 300 and 350 g. INTERVENTIONS: Rats were bled to 30 mm Hg for 30 mins by withdrawal/reinfusion of shed blood and Ringer's lactate equivalent to the shed blood volume. MEASUREMENTS: Rats were killed immediately, 4 hrs, or 24 hrs after reperfusion. Portal venous blood, splenic macrophages, and small bowel mononuclear cells were obtained and spontaneous (unstimulated) and endotoxin-induced supernatant tumor necrosis factor (TNF)-alpha (WEHI 164 subclone 13) and interleukin (IL)-6 (B 13-29 clone 9) release was measured by bioassay. MAIN RESULTS: Increased endotoxin-induced TNF release from gut mononuclear cells and portal venous blood was suppressed 4 and 24 hrs after reperfusion compared with sham operated animals (p < .05). TNF release from splenic macrophages could be significantly increased (p < .05) by addition of endotoxin in all groups with no difference between control, sham, and shock animals. In shock animals, endotoxin-stimulated IL-6 release was significantly greater (p < .05) than control and sham operated rats 4 hrs after reperfusion in portal blood and from splenic macrophages. In contrast to splenic macrophages, gut mononuclear cells and portal venous blood demonstrated high spontaneous IL-6 concentrations without further stimulation by endotoxin. CONCLUSIONS: Hemorrhagic shock induced a hyporesponsiveness from gut mononuclear cells and whole portal venous blood 4 and 24 hrs after reperfusion. Spontaneous and endotoxin-induced stimulation of IL-6 indicates a different modulation of cytokines in gut, portal vein and spleen. The differences of gut mononuclear cells and portal blood compared with the splenic macrophages indicate a compartmentalized cytokine response.     

Solution structure of synthetic peptide inhibitor and substrate of cAMP-dependent protein kinase. A study by 2D H NMR and molecular dynamics

Altered hepatic expression of apolipoproteins occurs during the acute phase response. Here we examined whether the acute phase response alters extra hepatic expression of apolipoproteins. Syrian hamsters were injected with endotoxin (LPS), tumor necrosis factor (TNF), interleukin (IL)-1, or the combination of TNF + IL-1 and mRNAs for serum amyloid A (apoSAA), apolipoprotein (apo) J, apo E. apo A-I, and apo D, were analyzed. LPS increased mRNA levels for apoSAA in all tissues examined. LPS and TNF + IL-1 increased mRNA levels for apo J in kidney, heart, stomach, intestine, and muscle. Individually, TNF and IL-1 were less potent than the combination of the two cytokines. LPS decreased mRNA levels for apo E in all tissues, except for mid and distal intestine. TNF and IL-1 were less effective than LPS. LPS, TNF + IL-1 and TNF decreased mRNA levels for apo A-I in duodenum. mRNA for apo D decreased in heart, were unchanged in brain and increased in muscle, following LPS. The widespread extra hepatic regulation of the apolipoproteins during the acute phase response may be important for the alterations in lipid metabolism that occur during infection and inflammation as well as the immune response.     

Inhibitory effect on LPS-induced tumor necrosis factor in calves treated with chlorpromazine or pentoxifylline

The inhibitory effect of chlorpromazine (CPZ), pentoxifylline (PTX) and dexamethasone (DEX) was investigated in a model of endotoxin shock in Holstein calves following an intravenous administration of Esherichia coli endotoxin (LPS). Initial correlations with its effects on the levels of tumor necrosis factor (TNF), a pivotal mediator of endotoxin shock, and clinical signs were obtained. The pretreatment of CPZ or DEX significantly decreased the serum levels of TNF, and reduced endotoxic shock. But the pretreatment of PTX hardly reduced the increase of serum TNF levels and endotoxin shock. The levels of serum endotoxin were not significantly different a minute of postinjection of LPS in calves. The results of this study indicate that pretreatment of CPZ or DEX inhibit various biological effects on endotoxin in calves.     

Interferon-gamma potentiates interleukin (IL)-6 and tumor necrosis factor-alpha but not IL-1beta induced by endotoxin in the brain

Because interferon-gamma (IFN gamma) is present in the central nervous system during neurologic diseases associated with inflammation, its effect on endotoxin-induced cytokines was studied. Cerebrospinal fluid (CSF) and serum levels of interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha (TNF alpha), their messenger RNA expression in brain areas (hypothalamus, hippocampus, and striatum) and in spleen were evaluated 2 and 8 h after endotoxin [lipopolysaccharide (LPS), 25 microg/rat i.c.v.], IFN gamma (2.5 microg/rat i.c.v.) or after their coadministration in rats. CSF and serum IL-1beta levels were increased by LPS alone and IFN gamma coadministration did not furtherly increase them. IFN gamma potentiated LPS effect on IL-6 and TNF alpha levels in both CSF and serum. LPS and IFN-gamma coadministration did not alter IL-1beta messenger RNA expression induced by LPS in brain areas and in spleen, but it potentiated that of IL-6 and TNF alpha. The present in vivo data show that i.c.v. coadministration of LPS and IFN gamma results in a potentiation of cytokine production (IL-6 and TNF alpha) which may trigger a cascade of events relevant to neurodegenerative processes. This action is independent of IL-1beta because the production of this cytokine is not altered by IFN gamma treatment.     

Effects of interleukins on secretion of luteinizing hormone from ovine pituitary cells

OBJECTIVE: To determine whether cytokines of homologous species might mediate the stimulatory effects of endotoxin on release of luteinizing hormone (LH) from pituitary cells. SAMPLE POPULATION: Cells from pituitary glands collected from 8- to 14-month-old wethers. PROCEDURE: Cells from the anterior pituitary gland were cultured in the presence of recombinant ovine or bovine cytokines (interleukin [IL]-1alpha, IL-1beta, and IL-2), tumor necrosis factor-alpha (TNF), and interferon-gamma (IFN-gamma). Luteinizing hormone that was released into the medium was measured. Cells were also cultured with modulators of signal transduction pathways to evaluate the second messenger system used by IL-1 alpha and IL-1beta. RESULTS: Similar to effects of endotoxin, IL-1alpha and IL-1beta stimulated release of LH. Interleukin 2, TNF, and IFN-gamma did not have a detectable effect on release of LH. Stimulation of LH release by IL-1alpha and IL-1beta required activation of voltage-dependent Ca2+ channels and appeared to involve protein kinase C. CONCLUSIONS: IL-1alpha and IL-1beta may mediate the direct stimulatory effect of endotoxin on release of LH in vitro. Interleukin 2, TNF, and IFN-gamma do not have a direct effect on release of LH; therefore, they do not mediate this effect of endotoxin. CLINICAL RELEVANCE: Stressors, including infection, are often associated with reduced fertility. Infection resulting in endotoxin release, production of interleukins, or both, can lead to direct stimulation of LH release from the pituitary gland. Inopportune release of LH via cytokines may interfere with normal pulsatile release of LH, thereby suppressing gonadal function.     

Cytokines in vitreous humor: interleukin-6 is elevated in proliferative vitreoretinopathy

PURPOSE: To measure the levels of interleukins (IL) 1 beta, 6, and 8, and tumor necrosis factor-alpha (TNF alpha) in the vitreous of patients with proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), vitreous hemorrhage, and macular pucker. METHODS: Vitreous samples were collected, undiluted, from patients with PVR, PDR of varying severity, and miscellaneous lesions (vitreous hemorrhage from trauma, macular degeneration, vein occlusion, and non-PVR patients with giant tear, retinal detachment, and macular pucker). Immunoreactive levels of the cytokines, IL-1 beta, IL-6, IL-8, and TNF alpha were determined by enzyme-linked immunoadsorbent assays, and samples were analyzed for protein and hyaluronic acid content using standard assays. RESULTS: The levels of TNF alpha were below detection limits of the assay (< 3 pg/ml). In 45 of the 47 samples tested, IL-1 beta levels also were below detection limits of the assay (< 3 pg/ml). IL-6 levels ranged from < 30 to 5487 pg/ml, with the highest values observed in the PVR patients. IL-8 levels ranged from < 20 to 1900 pg/ml, and were consistently high in the miscellaneous group. Some of the PVR patients with C2 and C3 level severity also exhibited IL-8 levels exceeding 100 pg/ml. In a second study, IL-6 content of vitreous from miscellaneous and PVR patients was compared. In this study, significantly elevated levels of IL-6 were observed in the PVR patients (91.5 +/- 18 pg/ml) compared to the miscellaneous group (10.3 +/- 3.7 pg/ml) CONCLUSIONS: Elevated levels of IL-6 in the vitreous occur in PVR, implicating a role for this cytokine in the pathogenesis of this ocular disorder.     

Research on the mechanism of endothelin inflammatory effects on human mesangial cells

OBJECTIVE: To investigate the mechanism of endothelin (ET) inflammatory effects on human mesangial cells (HMC). METHODS: The following experiments were performed on cultured HMC after ET-1 stimulation: (1) the expression of tumor necrosis factor-alpha (TNF alpha), interleukin-1 beta (IL-1 beta), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and endothelin-1 (ET-1) itself messenger ribonucleic acid (mRNA) was determined by Northern Blot analysis; (2) the TNF alpha concentration was tested with radioimmunoassay; the IL-1 activity was assayed by the enhancement of thymocyte proliferation in response to mitogen; the surface expression of ICAM-1 and VCAM-1 was measured with cell enzyme linked immunoadsorbent assay (ELISA) analysis. RESULTS: ET-1 (10(-7) mol/L) induced the following changes on HMC: (1) up-regulation of the expression of TNF alpha mRNA and protein; (2) up-regulation of the expression of ICAM-1 and VCAM-1 mRNA and protein; (3) up-regulation of the expression of ET-1 itself mRNA. However, the expression of IL-1 mRNA and protein was not changed. CONCLUSIONS: ET-1 can stimulate HMC to produce TNF alpha, ICAM-1 and VCAM-1, and thereby induce inflammatory effects. ET-1 can also stimulate HMC to up-regulate the expression of ET-1 itself, so as to amplify inflammatory effects. So, ET-1 is actually an inflammatory mediator and may play an important role in the pathogenesis of glomerulonephritis.     

Resistance to endotoxin shock in spontaneously hypertensive rats

Septic shock involves systemic vasodilation mediated by proinflammatory cytokines. In essential hypertension, vascular and immune dysfunctions are closely associated. The response of hypertensive animals compared with normotensive controls to endotoxin (lipopolysaccharide; LPS) challenge is not known. Age-matched (12 weeks) normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were exposed to intravenous injection of 10 mg/kg LPS. Survival rate at 24 hours was markedly higher in SHR than in WKY (12 of 15 and 3 of 15, respectively; P<0.01). Survival of LPS-injected SHR was not related to their hypertension because hydralazine-treated SHR with normalized pressure had similar survival rates, and WKY made hypertensive by clipping of one renal artery showed fatality similar to that of normotensive WKY. Continuous arterial pressure and sequential plasma levels of interleukin-6 (IL-6) and tumor necrosis factor (TNF) were measured in LPS-treated SHR and WKY. Both the duration of the delayed hypotensive phase and the systemic release of IL-6 were much lower in SHR than WKY, whereas both acute hypotension and plasma TNF peak were equivalent. We further explored in vitro the inflammatory response and showed that LPS-activated whole blood from SHR produced less TNF and IL-6 than WKY LPS-activated whole blood. Our results indicate that SHR have a greater ability to resist endotoxic shock than WKY. This is not related to their hypertension but is associated with an attenuated inflammatory response to LPS.     

Pentoxifylline attenuates neutrophil activation in experimental endotoxemia in chimpanzees

Costimulation of neutrophils and cytokines may play an important role in organ injury in sepsis. Pentoxifylline inhibits various neutrophil functions in vitro, and attenuates endotoxin-induced production of TNF in both in vitro and in vivo models. To assess the effect of pentoxifylline on neutrophil activation in endotoxemia, nine adult chimpanzees (Pan troglodytes) were i.v. injected with saline (n = 2), Escherichia coli endotoxin (4 ng/kg; n = 4), or E. coli endotoxin (4 ng/kg) in combination with pentoxifylline (500 mg/3 h, starting 30 min before the endotoxin injection; n = 3). Serial blood samples were obtained for measurements of leukocyte counts and the granulocytic proteinases elastase complexed with alpha 1-antitrypsin and lactoferrin, and cytokines during the next 5 h. No changes were observed in the saline-treated chimpanzees. Endotoxin induced a marked leukocytosis and neutrophilia, which were slightly reduced by pentoxifylline. In contrast, pentoxifylline almost completely prevented endotoxin-induced neutrophil degranulation: peak elastase-alpha 1-antitrypsin was 164 +/- 21 ng/ml (mean +/- SE) after endotoxin alone, vs 71 +/- 7 ng/ml after endotoxin with pentoxifylline (t = 3 h; p < 0.05); peak lactoferrin was 329 +/- 15 and 182 +/- 5 ng/ml, respectively (t = 5 h; p < 0.05). Pentoxifylline also inhibited the endotoxin-induced release of TNF (271 +/- 26 vs 55 +/- 23 pg/ml at t = 1.5 h; p < 0.05) and IL-6 (225 +/- 42 vs 73 +/- 25 pg/ml at t = 2 h; p < 0.05). IL-8 release was not significantly inhibited by pentoxifylline. In none of the animals activation of the C system could be detected. We conclude that pentoxifylline attenuates neutrophil activation in endotoxemia in chimpanzees, probably in part by inhibiting the release of TNF.     

Role of beta-adrenoceptor on renal interleukin-6 and tumor necrosis factor in spontaneously hypertensive rats

We have shown previously in the spontaneously hypertensive rat (SHR) kidney that interleukin-6 (IL-6) and tumor necrosis factor (TNF) mRNA levels were low under conditions of acute anaesthesia and surgical stress. The reasons for the suppression of IL-6 and TNF gene expression in the SHR were investigated by examining the influence of enhanced beta-adrenergic stimulation, high blood pressure, and renal function (renal blood flow, glomerular filtration rate, plasma creatinine levels) on renal IL-6 and TNF mRNAs. The experiments were performed by means of the following three studies; (1) SHR and Wistar rats at 4, 7, 9 week old were injected with lipopolysaccaride (LPS), and then a relationship between blood pressure levels and IL-6 and TNF mRNA levels were estimated, (2) isoproterenol and propranolol were administered into SHR and WKY rats, and the levels of IL-6 and TNF mRNA were compared, (3) under condition of anaesthesia and surgical stress, blood pressure and renal functions in SHR were measured, and then the relationships between these factors and IL-6 or TNF mRNA levels were analyzed. Renal IL-6 and TNF mRNAs in SHR remained low even though blood pressure increased with age and there was no significant correlation between IL-6 or TNF mRNA levels and values of blood pressure or renal function under anaesthesia and surgical stress. However, the inhibition of the IL-6 and TNF mRNAs in SHR was prevented by propranolol treatment. These results suggested that suppression of IL-6 and TNF mRNAs in the SHR kidney could be due to overactivity of beta-adrenergic influences which may importantly contribute to the development of hypertension.     

Benzydamine protection in a mouse model of endotoxemia

OBJECTIVE: Previous studies have shown that benzydamine (40 mg/kg s.c.) is able to inhibit tumor necrosis factor (TNF) production and to reduce mouse lethality when administered before or concomitantly with LPS. The present study was designed to further investigate benzydamine activity against LPS-induced toxicity in terms of potency and therapeutic effects. METHODS: Female Balb/c mice were used. A dose-response curve of animal lethality versus endotoxin dose was performed (LD50 = 45 micrograms/mouse). Therapeutic effects were studied selecting the dose of LPS to achieve an LD100 (160 micrograms/mouse). Mortality was assessed daily and mice were followed for 8 days. The potential mode of action of therapeutically administered benzydamine was also investigated. TNF alpha and IL-1 beta levels were measured, at 5 h after LPS injection, both in sera and in lungs. Moreover, the drug was assayed in a TNF-dependent cytoxicity test. RESULTS: Benzydamine, administered at 20 mg/kg s.c. simultaneously with the endotoxin, significantly increased LPS LD50 up to 230 micrograms/mouse (p < 0.05). Moreover, the drug significantly protected mice against LPS-induced lethality when administered either 30 min or 4 h after endotoxin injection (p < 0.001). Benzydamine, therapeutically administered at 20 mg/kg s.c., significantly reduced TNF alpha and IL-1 beta production induced by LPS both in serum and lungs and it was shown to inhibit TNF-dependent cytoxicity on L929 cells. CONCLUSIONS: These results clearly demonstrate the therapeutic activity of benzydamine in a simple model of endotoxic shock. Available data confirm the potential role of benzydamine as an anti-cytokine agent and provide suggestions for novel therapeutic applications of this anti-inflammatory drug.