Biomedical subjects

R C Barbacane

Publications and source records attributed to R C Barbacane.

At least 37 records · Page 2Linked to original sources

PubMed1997

Massive infiltration of basophilic cells in inflamed tissue after injection of RANTES.

Regulated upon activation normal T expressed and secreted (RANTES) is a new inducible protein member of the human C-C branch of chemokines. RANTES is a potent monocyte and lymphocyte chemoattractant and is a mediator of inflammatory responses. In these studies we found that RANTES 10 ng/50 microl chemoattracts basophilic cells in a dose-dependent manner 4 h after an intradermal injection in rat skin sites, as revealed by optic microscopy. Moreover, in biopsy specimens from rat skin injection sites histamine release was significantly higher (P < 0.05) than in controls (PBS 50 microl) after 4 h from RANTES treatment. The presence of basophilic cells in rat skin injection sites after RANTES-treatment was also confirmed by electron microscopy studies. In addition, histidine decarboxylase (HDC) mRNA was increased in rat skin sites injected with RANTES compared to sites injected with PBS (controls). Our report describes additional biological activities for RANTES, suggesting that this human chemoattractant protein may play a fundamental role in histamine and HDC generation, along with basophilic cell recruitment.

Animals↗

PubMed1997

Infra-red laser irradiation enhances interleukin-1 receptor antagonist, increases 3H-thymidine incorporation and the release of [3H]arachidonic acid in human monocytes.

The effect of infra-red laser irradiation has been experimented on various biological systems and particularly in human tissues, in vitro as well as in vivo. In order to examine the influence of laser irradiation on cells of the monocytic lineage we have irradiated human peripheral blood mononuclear cells with an infra-red laser at a wavelength of 904 nm, at 2000 Hz frequency and 15 mW for 2 min. Here, we report that laser irradiation for 2 min. at different preincubation times (T = 0 and T = 30 min) enhances LPS (10 micrograms/ml or PHA (10 micrograms/ml, suboptimal concentration)-stimulated monocytes by modifying cell proliferation, as judged by [3H] thymidine incorporation. IL-1 receptor antagonist (IL-1ra) along with an increased release of [3H] Arachidonic acid production, is also influenced by laser irradiated monocytes when treated for 2 min after 1 h incubation. IL-1RA production increased 4-5 fold after laser irradiation, while 3H-arachidonic acid incorporated from PMA-stimulated cells increased and the effect was significant at T = 0 and T = 30 min; while at T = 1 h the effect was negligible. These results may provide new information regarding the effect of laser irradiation on the immune system.

Arachidonic Acid↗

PubMed1997

Augmentation of monocyte chemotactic protein-1 and mRNA transcript in chronic inflammatory states induced by potassium permanganate (KMnO4) in vivo.

Monocyte chemotactic protein-1 (MCP-1) is a proinflammatory cytokine that attracts and activates specific types of leucocytes. The purpose of this work was to analyse the generation of MCP-1 and mRNA transcript in a model of chronic inflammation using a granulomatous tissue induced by potassium permanganate (KMnO4; water soluble crystals). The data presented here shows that MCP-1 is generated in granuloma tissue and its level was strongly increased by i.p. injections of lipopolysaccharide (LPS) and inhibited in rats treated with injections of dexamethasone, 18 hr before the animals were killed. In histological studies LPS and dexamethasone increased and decreased, respectively, the recruitment of mononuclear cells in the granuloma tissue compared with the control granulomas from phosphate-buffered saline (PBS)-treated animals. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used for mRNA extraction and cDNA synthesis. mRNA MCP-1 was significantly produced in the granuloma tissue of untreated animals, an effect increased by LPS and inhibited by dexamethasone, compared with the controls. Moreover, MCP-1 protein was found in the supernatant from homogenized granuloma tissues and the levels of MCP-1 were higher in the LPS-treated animals, while they were lower in the dexamethasone group, compared with the granulomas from the PBS-treated groups (control). The generation of MCP-1 was also found in minced granuloma tissue incubated for 18 hr (overnight) from treated (LPS or dexamethasone) and untreated (PBS) rats. When LPS was added in vitro for 18 hr to the controls and treated animals the production of MCP-1 was further increased except in the dexamethasone group (P > 0.05). Analysing blood serum from LPS, dexamethasone or PBS-treated rats, we found that MCP-1 was also present. The level was higher in the LPS group and lower in the dexamethasone group, compared with the control (PBS). In these studies we show for the first time that MCP-1 transcript and translation is generated in chronic experimental inflammatory tissue, an effect inhibited by dexamethasone.

Animals↗

PubMed1997

Monocyte chemotactic protein-1 is a proinflammatory chemokine in rat skin injection sites and chemoattracts basophilic granular cells.

Chemokines may control mast cell infiltrates found in many inflammatory diseases. These cells act through at least two main functions: migration and degranulation. Here we show that human recombinant monocyte chemotactic protein (MCP)-1 (10 ng/50 microliters) induces, after 4 h, an inflammatory vascular permeability and cellular extravasation reaction, determined by Evan's blue dye (1% in saline) injected into the tail vein of the rat, when injected intradermally in the rat skin. The blue color accumulating at the sites of injection provides evidence of vascular permeability and cellular extravasation. The colored areas of the skin were then enucleated and immersed in a fixative solution. Slides were prepared with sections of tissue colored with toluldine blue and analyzed under an optical microscope. A significant number of basophilic cells migrated to the injected area where MCP-1 (10 ng/50 microliters) was used compared to the control PBS treatment. Cell recruitment was slightly less than N-formyl-methionine-leucyl-phenylalanine (used at 10(-6) M/50 microliters). Electron microscopy studies confirmed the presence of basophilic granular cells where MCP-1 was intradermally injected. After preparation of a histidine decarboxylase (HDC) probe, a Northern blot analysis was determined for HDC mRNA in the enucleated tissue injected with MCP-1 (10 ng/50 microliters). Steady-state levels of HDC mRNA levels were induced after 4 h. These results were confirmed by the higher amount of histamine release, compared to the control PBS, in the enucleated tissue from the MCP-1 injection sites. Our results suggest that MCP-1 could play a significant role in diseases characterized by basophilic cell accumulation and migration to sites of tissue damage. Moreover, we show for the first time that MCP-1 is a pro-inflammatory chemokine that induces basophilic cell migration in rat skin injection sites.

Animals↗

PubMed1996

Human recombinant interleukin-1 beta induces thromboxane A2 release in polymorphonuclear leukocytes, macrophages and platelets: effect of IL-1 receptor antagonist.

Prostaglandins and thromboxanes (Txs) are produced by polymorphonuclears (PMNs) and macrophages (Mphis) in response to various stimuli. PMNs were separated from other human blood cells and Mphis were separated from rat peritoneal lavage. In this paper we show that human recombinant interleukin-1 (hrIL-1) can stimulate the release of thromboxane B2 (TxB2) by PMNs and Mphis. In addition, we have shown that aggregation of PMNs may occur when calcium ions (7 mM) and hrIL-1 (100 ng/ml) are added to the cell preparation, but not when Ca2+ alone, hrIL-1 alone, or first hrIL-1 then calcium are added to the cell preparation. The treatment of human platelets with hrIL-1 shows that after 15 min incubation TxB2 is released. In addition, we compared the aggregation of platelets caused by ADP with that caused by hrIL-1. Human recombinant IL-1 at a concentration of 100 ng/ml also causes little aggregation of platelets, in this case the aggregation is reversible. In conclusion, hrIL-1 beta stimulates TxB2 release in PMNs, Mphis and platelets and this effect increases with addition of Ca2+ ions. The mixture of hrIL-1 and Ca2+ causes little aggregation of PMNs. In monocyte suspensions, pretreated with human recombinant IL-1 receptor antagonist (IL-1ra) 500 ng/ml for 10 min and then treated with LPS or hrIL-1 beta 10 micrograms/ml, the release of TxB2 was partially inhibited. IL-1ra may play a significant role in the control of IL-1 and LPS induction in the release of TxB2.

Adenosine Diphosphate↗

PubMed1996

Effect of interleukin-1 receptor antagonist (IL-1RA) on histamine and serotonin release by rat basophilic leukemia cells (RBL-2H3) and peritoneal mast cells.

Recently, it has been appreciated that cultured mast cells are significant sources of cytokines. However, the role of interkeukin-1 (IL-1) on mast cells and/or basophil degranulation is still unclear. In this report we provide evidence that rat basophilic leukemia cells (RBLC) cultured with a natural inhibitor of IL-1, interleukin-1 receptor antagonist (IL-1RA) (500 ng/ml) for 48 h, strongly inhibited the spontaneous release of serotonin (5HT) and histamine (from 22.50 to 43.49%), compared to untreated cells (control). When IL-1RA-treated and untreated RBLC were stimulated with a secretagogue (anti-IgE), no difference was found in the percent of 5HT and histamine release. Moreover, in another set of experiments using rat peritoneal mast cells (RPMC) treated and untreated with IL-1RA, we found that IL-1RA did not affect the release of 5HT or histamine, even when the secretagogue anti-IgE or compound 48/80 (C48/80) were used. The present studies describe an additional biological activity of IL-1RA, inhibiting histamine and 5HT release from RBLC cultures.

Animals↗

PubMed1996

Generation of TNF alpha, IFN gamma, IL-6, IL-4 and IL-10 in mouse serum from trichinellosis: effect of the anti-inflammatory compound 4-deoxypyridoxine (4-DPD).

Infections caused by the nematode Trichinella spiralis is characterized in the host by an inflammatory response with cytokine production. In these studies we have detected TNF alpha, IL-6, IFN gamma, IL-4 and IL-10 in the serum of 10 mice infected with T. spiralis. Moreover, we detected, for the first time, these cytokines in the serum of mice treated with 4-DPD, a potent antagonist of vitamin B6 coenzyme which has anti-inflammatory properties. 4-DPD was used at 100, 400, 800 micrograms/bolus for 20 days, starting one day before the infection. After 15 days of T. spiralis infection, TNF alpha reached a maximum level, while IL-6 was maximal after 7 days, IFN gamma at 20 days and IL-4 at 14 days. IL-10 was not affected by the T. spiralis infection. When the animals were treated with 4-DPD at the reported dosages and infected with T. spiralis the inhibition of TNF alpha and IL-6, were dose-dependent in the first 7 days while IL-4 was reduced only at 400-800 micrograms/bolus. 4-DPD-treated mice did not statistically (P > 0.05) affect the generation of IFN gamma. In healthy animals the production of cytokines were not measurable, just as it was in non-infected animals treated with 4-DPD. The increase of cytokines such as, TNF alpha and IL-6 may be related to the severity of the disease, boosting the host's resistance to the pathogen and inhibiting parasite survival. In addition, the augmentation of IL-4 production enhances T and B cells and macrophage responses and may stimulate T-cell antibody-mediated response to the pathogen. 4-DPD, an inhibitor of IL-1 and inflammatory reactions, proved to be most effective on TNF alpha and IL-6, which are mainly produced by macrophages.

Animals↗

PubMed1996

Down-regulation of cyclooxygenase-2 (COX-2) by interleukin-1 receptor antagonist in human monocytes.

Cyclooxygenase (COX) is the key rate-limiting enzyme in the synthesis of prostanoids from arachidonic acid. Two isoforms of COX have been described in mammalian cells, referred to as cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2). COX-1 is a constitutively expressed enzyme; COX-2 is an inducible enzyme that appears to be expressed in inflamed tissue and following exposure to growth factors or cytokines, such as interleukin-1 (IL-1). The aim of the present study was to test if the antagonism on the binding of IL-1 to its cell-surface receptor by human recombinant IL-1 receptor antagonist (hrIL-1ra) may control the COX mRNA expression and prostaglandin E2 (PGE2) production by human monocyte cultures. Northern blot studies showed that hrIL-ra (500 ng/ml) had a strong inhibitory effect on inducible COX activity. The effect was evident after 6 hr incubation (2.7-fold decrease of mRNA COX-2 transcripts); and about a threefold decrease at 24hr incubation. A non-significant effect was observed with COX-1 transcripts. Induced PGE2 production by monocyte cultures treated with lipopolysaccharide (LPS) or interleukin-1 beta (IL-1 beta) was strongly inhibited in the presence of hrIL-1ra (500 ng/ml). In addition, a significant inhibition of COX-2 protein expression, as evaluated by Western blotting, was also observed. These data suggest that hrIL-1ra may be the key mediator in the down-regulation of the COX-2 inducible pathway.

Blotting, Northern↗

PubMed1995

The down-regulation of IL-6-stimulated fibrinogen steady state mRNA and protein levels by human recombinant IL-1 is not PGE2-dependent: effects of IL-1 receptor antagonist (IL-1RA).

Infections, trauma and inflammatory processes induce a host response with increases in a large group of structurally and functionally diverse plasma proteins. Parental administration of foreign proteins also induce an increase in plasma fibrinogen. Interleukin-6 (IL-6) is a monocyte-derived mediator and has regulatory effects on acute phase protein genes which result in the induction of fibrinogen synthesis in primary hepatocytes, while the addition of interleukin-1 (IL-1) exerts a negative modulating influence on the IL-6-stimulated fibrinogen. In order to understand the mechanisms by which IL-1 inhibits IL-6-stimulated fibrinogen transcription and translation, and since IL-1 is believed to act through PGE2 stimulation, we have studied the influence of PGE2 in IL-6 or IL-1, alone and in combination, on Fg mRNA expression (by Northern blot analysis) and the influence of PGE2, indomethacin, and arachidonic acid on Fg secretion. Moreover, since human recombinant interleukin-1 receptor antagonist (hrIL-1ra) is a strong inhibitor of IL-1 induced IL-1 transcription and translation and has an inhibitory effect on PGE2, we have studied the effects of IL-1ra on the down-regulation of IL-6 stimulated fibrinogen by IL-1, using an Fg ELISA method.(ABSTRACT TRUNCATED AT 250 WORDS)

Arachidonic Acid↗

PubMed1995

Synergistic activation of serum amyloid A (SAA) by IL-6 and IL-1 in combination on human Hep 3B hepatoma cell line. Role of PGE2 and IL-1 receptor antagonist.

Serum amyloid A (SAA) protein is a major acute phase reactant in human and many other species. Infections and traumatic inflammation are characterized by a rapid increase of SAA; its concentration in the plasma may augment many-fold. Cytokines such as IL-1 and IL-6 are considered mediators of acute phase protein synthesis. The most accredited mechanism of action of IL-1 in inflammatory diseases is the stimulation of PGE2 release, which is highly dependent on the concentration of IL-1. In this study we found that human Hep 3B hepatoma cells treated with the combination of hrIL-6 (10ng/ml) plus hrIL-1 (1ng/ml) produced an augmentation in steady-state levels of SAA mRNA (87%) compared to hrIL-6 (10ng/ml) plus PGE2 (5 microM), which induced an increase of only 33%, compared to IL-6 alone, while cells treated with hrIL-6 plus PGE2 (0.5 microM) had a similar effect as hrIL-6 did alone. Moreover, the addition of exogenous PGE2 (5 microM) to the cell cultures produced no significant increase in concentration of SAA mRNA compared to the control. In addition, according to the data obtained by the blot analysis we also found, by ELISA method, that hrIL-6 acts in synergism with hrIL-1 on SAA protein secretion in human Hep 3B hepatoma cell cultures after 48 h incubation. In fact, the cell cultures treated with hrIL-6 plus hrIL-1 caused a higher release approximately 1.5-4-fold of SAA protein than the cells treated with IL-6 plus PGE2 5 microM or IL-1 + PGE2 5 microM, respectively. The synergistic effect of hrIL-6 plus hrIL-1 beta was inhibited by hrIL-1 receptor antagonist (hrIL-1ra) 50 micrograms/ml, a protein which specifically binds to the IL-1 receptor and is structurally similar to IL-1 beta but with no IL-1-like activity; while indomethacin (5 microM) was ineffective. These results strongly suggest that the synergism between hrIL-6 plus hrIL-1 on the transcription and the protein release of SAA release is not due to a PGE2-dependent process in human Hep 3B hepatoma cells. This finding highlights a specific biological effect of IL-1 not in relation to PGE2, suggesting a specific mechanism of action for IL-1 in regulating acute phase protein synthesis.

Arachidonic Acid↗

PubMed1995

Monocyte chemotactic protein-1 provokes mast cell aggregation and [3H]5HT release.

Monocyte chemotactic protein-1 (MCP-1) and MCP-3, the most active and representative compounds of the CC chemokine family, are proinflammatory cytokines that attract and activate specific types of leucocytes. We have used highly purified isolated rat peritoneal mast cells (RPMC) cultured for different lengths of time with and without MCP-1 (200, 100, 50 and 25 nM). Our data clearly show that MCP-1 (200 nM) causes a marked release of [3H]serotonin ([3H]5HT and histamine, which reach a peak at 40 min of incubation (56.6 +/- 5.3 and 34.7 +/- 6 above the control, respectively). In dose-response experiments, MCP-1 (200, 100, 50, 25, 12.5, 6.25 and 3.12 nM) provoked a dose-dependent release of [3H]5HT and histamine from RPMC, which was maximum at 200 nM. After preparation of the histidine decarboxylase (HDC) probe, a Northern blot analysis was determined for HDC mRNA. After 4 hr, steady-state levels of HDC mRNA were induced in a dose-dependent manner by MCP-1 (200-25 nM), compared to the controls. However, MCP-1 failed to prime RPMC in [3H]5HT and histamine release when C48/80 (0.05 micrograms/ml) or anti-IgE was used. In contrast, murine interleukin-3 (IL-3) in combination with MCP-1 (200 and 100 nM) provoked a greater release of histamine and [3H]5HT than the compounds alone. Moreover, RPMC treated with MCP-1 (200 nM) showed, under light microscopy (20x), greater clump formation, a phenomenon absent in the controls (untreated cells). The electron microscope studies revealed that treatment with MCP-1 (200 nM) promoted binding of RPMC and clearly demonstrated a communication between the cytoplasms of adjacent mast cells. Our report describes additional biological activities for MCP-1, suggesting for the first time that this human monocyte chemoattractant plays a fundamental role in histamine and serotonin release and cell aggregation in rat peritoneal mast cells.

Animals↗

PubMed1994

Reduced human lymphocyte blastogenesis and enhancement of adenosine triphosphate (ATP) by L-carnitine.

Carnitine is associated with lipid synthesis and its deficiency may lead to cardiomegaly with parenchymal lipid in the heart, kidney and liver. In our study we found that pretreatment of peripheral blood mononuclear cells (PBMC) with serial dilutions of L-Carnitine (100 micrograms/ml-1 pg/ml) inhibits, in a dose-dependent manner, lymphocyte DNA synthesis stimulated with PHA (20 micrograms/ml). L-Carnitine did not have any effect on resting PBMC. The maximum inhibition was found at 10 micrograms/ml of L-Carnitine. Moreover, in a time-course study and using an enzymatic analysis (ATP monitoring reagent), L-Carnitine enhanced ATP production on PBMC treated and untreated with PHA, reaching a maximum effect at 30 min incubation. In another set of experiments PBMC were treated with L-Carnitine alone and in combination with PHA, and the percent of receptors CD3, CD4, and CD8 were calculated with flow cytometry. After the cell incubation with L-Carnitine, the percent of all receptors studied did not change compared to L-Carnitine-untreated cells (controls). These data suggest that L-Carnitine inhibits, in a dose-dependent manner, lymphocyte blastogenesis induced by PHA, probably through the enhancement of ATP synthesis, which is considered an inhibitor of phospholipase C activity and a suppressor in lymphocyte cultures.

Adenosine Triphosphate↗

PubMed1994

Bacillus Calmette-Guérin potentiates monocyte responses to lipopolysaccharide-induced tumor necrosis factor and interleukin-1, but not interleukin-6 in bladder cancer patients.

During the past decade, particular attention has been focused on treatment of bladder cancer patients with the bacterial agent bacillus Calmette-Guérin (BCG). In these studies, bladder cancer patients were instilled with BCG (75 mg/50 ml) once per week for 6 weeks, 1-2 weeks following trans-urethral resection of the bladder. Cystoscopy was performed after 6 weeks and, unless tumor progression was present, monthly treatments were given for 1 year. Blood was drawn 2 h after the last instillation, and monocytes were isolated (5 x 10(6) cells/ml) and treated, or not, with lipopolysaccharide (LPS) (20 microgram/ml) for tumor necrosis factor alpha (TNF alpha), interleukin-1 alpha (IL-1 alpha) and interleukin-6 (IL-6) release. The levels of monokines were determined by a monokine-specific enzyme-linked immunosorbent assay. Our results clearly show that, after 18 h incubation, macrophages from BCG-treated bladder cancer patients produced from 2.8- to 1.9-fold and from 2.0- to 1.3-fold greater amounts of TNF alpha and IL-1 alpha respectively, compared to macrophages from healthy controls, 5-fold higher than bladder cancer patients not treated with BCG. IL-6 was not affected. In another set of experiments macrophages (5 x 10(6) cells/ml) from healthy subjects were pretreated, or not, with BCG (100 micrograms/ml) overnight and treated, or not, with LPS 20 microgram/ml alone and in combination with interleukin-1 receptor antagonist (IL-1ra) 250 ng/ml. Macrophages treated with BCG had a strong stimulatory effect on IL-1 alpha release (9.45 ng/ml) while LPS was less effective (3.59 ng/ml). The combination of BCG plus LPS produced an additive effect on IL-1 alpha release (13.71 ng/ml) compared to the effect of the compound alone. The addition of IL-1ra (250 ng/ml) to BCG was not effective, while when IL-1ra was added to BCG plus LPS only a partial inhibition of IL-1 alpha release was found (9.83 ng/ml), compared to BCG plus LPS without IL-1ra (13.71 ng/ml). These effects seem to be related to the inhibition of IL-1 alpha stimulated with LPS, but not BCG. The priming effect of BCG exerted on LPS-stimulated monocyte production of TNF alpha and IL-1 alpha from bladder cancer patients led us to study the possible modulation of fibrinogen and C-reactive protein in the serum of BCG-treated cancer patients. The plasma levels of fibrinogen and C-reactive protein were higher (approximately twice) in BCG-treated patients compared to values obtained in untreated patients or healthy controls. We conclude that the beneficial immunotherapeutic effects of BCG in bladder cancer patients are related to its capacity to prime macrophages to enhance the release of TNF alpha and IL-1 alpha, but not IL-6 in response to physiological secondary stimuli, or through the direct stimulation of BCG on IL-1 alpha or TNF alpha, which are directly involved in the killing of cancer cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗

PubMed1993

Inhibition of granuloma formation induced by potassium permanganate in the mouse by a specific human recombinant receptor antagonist for interleukin-1 (hrIL-1ra).

Interleukin-1 (IL-1) is a polypeptide which mediates several systemic changes associated with infection, inflammation and injury, such as fever, neutrophilia, increased acute phase protein synthesis, and arachidonic acid metabolites. Recently, a natural inhibitor of IL-1 has been cloned, called IL-1 receptor antagonist (IL-1ra), which prevents Escherichia coli-induced shock in rabbits and blocks PGE2 induced by IL-1. In this report we study the effect of human recombinant (hr) IL-1ra on chronic inflammation induced by dorsal injections of 200 microliters of a 1:40 saturated crystal solution of potassium permanganate (KMnO4) in mice. After 7 days, all mice developed a subcutaneous granulomatous tissue indicative of a chronic inflammatory response, at the site of injection. KMnO4-treated mice, injected intraperitoneally twice with hrIL-1ra, 20 micrograms/dose (the first at the same time of induction of the granuloma and the second 24 hr later), show significant decreases in size and weight of the granuloma when compared to mice not treated with hrIL-1ra (controls); the inhibitory effect was approximately 32-46 and 25-51%, respectively. In addition, in all mice treated with hrIL-1ra, there was a strong inhibition of PGE2 and LTB4 on assay of freshly minced granuloma tissue. Moreover, when hrIL-1 beta (1.0 ng/ml) or LPS (100 ng/ml) were added overnight to the minced granuloma tissue cultures, these compounds enhanced the production of LTB4 and PGE2 from the untreated mice, whereas in IL-1ra-treated mice they failed. In the histological studies of the granuloma, animals treated with hrIL-1ra show a lesser degree of mononuclear cell (MC) accumulation. The inhibitory effect of hrIL-1ra on PGE2 production was also confirmed on peritoneal macrophages from untreated mice, stimulated overnight with hrIL-1 beta or LPS in vitro. The resulting inhibition was dose-dependent. In these studies we show, for the first time, the anti-inflammatory effect of hrIL-1ra on chronic inflammation as assessed by the inhibition of granuloma formation, PGE2, LTB4, and white cell accumulation in inflamed tissue.

Animals↗

PubMed1993

Interleukin-1 receptor antagonist inhibits calcium accumulation in in vivo chronic granuloma induced by potassium permanganate.

Interleukin-1 (IL-1) is a monokine that exerts multiple biological activity, including immunity and inflammation. Moreover, IL-1 is involved in Ca2+ release causing hypercalcemia and bone resorption. Recently, a 22 kDa natural inhibitor to IL-1 called interleukin-1 receptor antagonist (IL-1ra) has been described in human fluids, which specifically binds IL-1 alpha or IL-1 beta receptors. In this study, we found that experimental granuloma induced by subcutaneous injections (0.2 ml) of potassium permanganate (KMnO4) 1:40 saturated crystal solution, after 7 days was strongly inhibited in size, weight and calcium content (measured as dry ash weight by incineration of granuloma tissue) compared with untreated controls, in mice treated intraperitoneally with IL-1ra (20 micrograms/bolus) given twice; the first at the same time of the induction of the granuloma and the second 24 hours later. In addition, leukotriene B4 and prostaglandin E2 were also inhibited in fresh granuloma of mice treated with IL-1ra. Taken together, these findings conclude for the first time, that the accumulation of calcium in chronic inflammatory states is strongly inhibited by IL-1ra, which decreases tissue calcergy and can potentially be useful for the treatment of calcium-related inflammatory diseases and malignancy-associated hypercalcemia.

Animals↗

PubMed1993

Effect of interleukin-1 receptor antagonist on vascular smooth muscle cell proliferation.

The development of the atheromatous plaque is largely dependent on vascular smooth muscle cell proliferation and production of biologically active compounds such as cytokines and growth factors. Cytokines such as IL-1 derived from blood vessel wall may contribute to regional defense or pathology. Neutralization of the effects mediated by IL-1 by a receptor antagonist specific for IL-1 alpha and IL-1 beta has been shown to reduce the possible pathologic consequences induced by IL-1 in the regional environment. The effect of human recombinant interleukin-1 receptor antagonist (hrIL-1ra), a new member of the IL-1 family, has been assessed on modulating vascular smooth muscle cell (VSMC) proliferation in the rat. A significant dose- and time-dependent reduction of DNA synthesis was observed when hrIL-1ra was added to the cell cultures. The maximum inhibitory effect was seen using IL-1ra at a concentration of 250 ng/ml and after 48 h incubation with cultured vascular smooth muscle cells. Furthermore, hrIL-1ra inhibited VSMC growth in the presence of exogenous mitogenic doses of IL-1 alpha. The addition of indomethacin to the cultures did not modify the inhibitory events. These data suggest a possible pharmacologic role for IL-1ra in inhibiting VSMC proliferation by possibly interfering with the autocrine regulatory pathway of IL-1.

Animals↗

PubMed1993

Human recombinant interleukin-1 receptor antagonist (hrIL-1RA) inhibits prostaglandin E2 (PGE2) generation but not alkaline phosphatase activity in in vivo chronic granulomatous tissue induced by KMnO4.

Interleukin-1, a soluble polypeptide, plays an important role in inflammatory reactions by increasing prostaglandin E2 (PGE2) generation. Human recombinant IL-1 receptor antagonist (hrIL-1ra) is a natural inhibitor of IL-1 which blocks its activity in several inflammatory states. In these studies we found that hrIL-1ra (250 mg/ml) inhibits the generation of PGE2, as measured by RIA method, in minced mouse granuloma tissue (700 mg) treated overnight with LPS (10-1000 ng/ml) or hrIL-1 beta (0.1-10 ng/ml). In addition, we show that hrIL-1ra (250 ng/ml) strongly inhibited IL-1 alpha and IL-1 beta, as measured by ELISA method, in the minced granuloma tissue treated overnight with LPS 1 micrograms/ml or IL-1 beta (10 ng/ml). The granuloma tissue induced in mice by a dorsal subcutaneous injection (0.2 ml) of a saturated solution (1:40 dilution) of KMnO4 crystals, presented an alkaline phosphatase activity which was not inhibited by two intraperitoneal administrations of hrIL-1ra 20 micrograms/200 ml bolus injections (given at the same time as KMnO4 injection and one 24 h later). These results show for the first time that hrIL-1ra blocks PGE2, IL-1 alpha and IL-1 beta but not alkaline phosphatase activity, which is a marker in growing bone and in calcific and inflamed tissue.

Alkaline Phosphatase↗

PubMed1993

Human recombinant IL-1 receptor antagonist (IL-1Ra) inhibits leukotriene B4 generation from human monocyte suspensions stimulated by lipopolysaccharide (LPS).

The effect of human recombinant IL-1 receptor antagonist (hrIL-1Ra) on leukotriene B4 (LTB4) release was investigated in activated human monocyte cultures. To stimulate LTB4 generation, LPS was used as an agonist. Detection was performed with the highly sensitive radioimmunoassay method. The cells were treated with scalar concentrations using LPS at 1-1000 ng/ml for different periods of time. The greater LTB4 stimulation was found at LPS 100 ng/ml for 18 h incubation time. Preincubation of monocytes with cytochalasin B (CB) (5 micrograms/ml) for 15 min augmented the release of LTB4 when LPS was used. A dose-dependent inhibition was found when human monocytes were pretreated for 10 min with hrIL-1Ra at different concentrations (0.25-250 ng/ml) and then treated with LPS 100 ng/ml for 18 h. Maximum inhibition was observed at the highest concentration of hrIL-1Ra (250 ng/ml). Macrophages treated with a non-selective 5-lipoxygenase inhibitor, nordihydroguaiaretic acid (NDGA), used at 10 microM, added 15 min before LPS 100 ng/ml, produce a dose-dependent inhibition of LTB4. Cells pretreated with arachidonic acid, at various concentrations (10(-9)-10(-5) M) for 10 min and then treated with LPS 100 ng/ml for 18 h, were also inhibited in a dose-dependent manner by hrIL-1Ra in their production of LTB4. The inhibition of LTB4 release by hrIL-1Ra, in LPS-stimulated human monocytes, may suggest an important modulatory role for this new cytokine (monokine) in inflammation and immunity and may hold future therapeutic implications for diseases involving LTB4 as a mediator.

Arachidonic Acid↗