[Effects of IL-1 receptor antagonist on the level of cytokine in the rat corneal grafts and aqueous humor after corneal transplantation]

OBJECTIVE

By detecting the expression of IL-1RI and TGF-beta(1) on the normal rat cornea and graft, and the amount of IL-1 beta in the aqueous humor of normal rat eye and the eye after keratoplasty, to investigate the relationship between these cytokines and graft rejection and to observe the effects of IL-1 receptor antagonist (IL-1ra) on graft rejection.

METHODS

All rats after keratoplasty were divided into five groups. Immunohistochemistry method and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression of IL-1RI and TGF-beta(1) on the normal rat cornea and graft and the amount of IL- 1 beta in the aqueous humor of normal rat eye and the eye after keratoplasty at different time points: pre-rejection, acute-rejection and two weeks after surgery.

RESULTS

IL-1RI could be detected in normal rat cornea. TGF-beta(1) expressed mainly in the epithelium of normal cornea, especially the basal cell layer and the basement membrane. After keratoplasty, IL-1RI and TGF-beta(1) could be detected in the corneal epithelium, stroma and endothelium, and the level of expression decreased in sequence as negative control group, 50 micro g IL-1ra group, 100 micro g IL-1ra group, 200 micro g IL-1ra group and dexamethasone group. In the acute rejection period, the expression of IL-1RI and TGF-beta(1) in the 200 micro g IL-1ra group was less than that of the 50 micro g IL-1ra group, the difference was significant (P < 0.01). The expression of IL-1RI and TGF-beta(1) in the negative control group was higher than that of all experimental groups, the difference was significant (P < 0.01). IL-1 beta was detected in normal aqueous humor; the mean level was (96.0 +/- 11.3) ng/L. In the eye after keratoplasty, the IL-1 beta level increased significantly compared to normal aqueous humor (P < 0.01). In the acute rejection period, the quantity of IL-1 beta reached its peak at (552.2 +/- 68.3) ng/L in the negative control group, which was the highest quantity of IL-1 beta in all experimental groups (P < 0.01). The IL-1 beta level in all experimental groups in the pre-rejection period had no difference compared with that in the acute rejection period (P > 0.05), but the level of IL-1 beta in the pre-rejection and rejection periods was significantly different compared with that in the post-rejection period (P < 0.01).

CONCLUSIONS

IL-1RI and TGF-beta(1) play a active role in the corneal graft immunogenic rejection. IL-1 beta is a key factor in starting corneal graft rejection. The keratoplasty graft rejecting reaction can be reduced and mean survival time can be prolonged by IL-1ra, which inhibits the expression of IL-1RI and TGF-beta(1) and decreases the level of IL-1 beta in the aqueous humor.

Comparison of inflammatory markers in patients with diabetes mellitus versus those without before and after coronary arterial stenting

Patients with diabetes are at increased risk for adverse events after coronary stenting, perhaps reflecting a pro-inflammatory state. To characterize the inflammatory response to coronary stenting in patients with and without diabetes, blood samples were obtained from 75 patients before stenting and 10 minutes, 1 hour, and 24 hours later. C-reactive protein (CRP, microg/ml), interleukin (IL)-6 (pg/ml), IL-1 receptor antagonist (pg/ml), and soluble CD40 ligand (ng/ml) were assayed in each sample by enzyme-linked immunosorbent assay. Concentration changes after stenting were identified by repeated-measures analysis of variance. Multivariate analysis was performed to delineate independent predictors of increased concentrations of inflammation markers. Overall, 88% of patients had acute coronary syndromes; 36% had elevated markers of cardiac injury. The preprocedural concentrations of CRP in those with diabetes were more than twice as high as those in patients without diabetes. Two independent predictors of elevated preprocedural CRP concentrations were diabetes (odds ratio 3.95, 95% confidence interval 1.17 to 13.4) and a cardiac marker-positive acute coronary syndrome (odds ratio 3.70, 95% confidence interval 1.22 to 11.2). Preprocedural concentrations of IL-6, IL-1 receptor antagonist, and soluble CD40 ligand tended to be greater in patients with diabetes. The increase in CRP after stenting was much greater for patients without diabetes compared with that in patients with diabetes such that the apparent intensity of inflammation after 24 hours was similar in those with and without diabetes. Thus, patients with and without diabetes exhibit different inflammatory responses to stenting, reflecting the lower preprocedural inflammation in those without diabetes versus those with diabetes.

Potential role of interleukin-1 at the peri-ovulation stage in a species of placental viviparous reptile, the three-toed skink, Chalcides chalcides (Squamata: Scincidae)

We recently showed that interleukin-1 (IL-1) is secreted by the placenta of a species of squamate reptile, the three-toed skink, Chalcides chalcides. In this study, we used immunohistochemical techniques to investigate the expression of IL-1 (in the two isoforms, IL-1alpha and IL-1beta) and its specific membrane receptor IL-1 RtI in uterine oviduct during the peri-implantation period. We found that both IL-1 and its receptor were expressed in uterine tissues before and after ovulation (in the pre-ovulatory stage, even before the yolk had formed in the ovary). However, while IL-1alpha was mostly localized in the uterine mesenchyme tissue, IL-1beta and IL-1RtI were present in the uterine epithelium. Our data provide a further comparison between the reproduction of mammals and squamate reptiles.

Modulation of cytokine release from colonic explants by bacterial antigens in inflammatory bowel disease

The intestinal flora play an important role in experimental colitis and inflammatory bowel disease (IBD). Using colonic explant cultures from 132 IBD and control subjects, we examined tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 and interleukin-1 receptor antagonist (IL-1RA) production in vitro in response to bacterial activators. Unstimulated TNF-alpha release was increased significantly in rectal biopsies from involved IBD tissue, correlating with inflammation severity. Whereas lipopolysaccharide (LPS) only moderately stimulated TNF-alpha production from inflamed tissue, pokeweed mitogen (PWM) induced its release in all groups, with a stronger response in involved IBD tissue. Superantigen staphylococcal enterotoxin A (SEA) had a similar, but weaker effect. SEB was observed to be the strongest inducer of TNF-alpha for all groups, again with a more marked response in inflamed tissue. Stimulated release of IL-1 was considerably less than for TNF-alpha. The superantigens' superior potency over LPS was not as marked for IL-1 as it was for TNF-alpha. In addition to IL-1, IL-1RA release was also triggered by the bacterial products. The net effect of activation on the IL-1RA/IL-1 ratio was relatively modest. Release of the proinflammatory cytokines TNF-alpha and IL-1, as well as that of the anti-inflammatory cytokine IL-1RA was increased by incubation of colonic tissue with bacterial factors. TNF-alpha production and release was increased significantly in involved colonic explants from IBD. SEB was even capable of inducing TNF-alpha release from uninvolved colonic tissue.

Inflammatory events are involved in acne lesion initiation

The earliest subclinical acne "lesion" is a microcomedone, of which hyperproliferation of the follicular epithelium is a characteristic feature. Inflammatory cells have been observed at the periphery of these "lesions". This study investigated whether inflammatory events occur pre or post hyperproliferative changes. Cellular, vascular, and proliferative markers were examined by immunohistochemical techniques on biopsies of clinically normal follicles from uninvolved skin and early inflamed lesions from acne patients. Control follicles were obtained from non-acne subjects. Follicles from uninvolved skin exhibited no microcomedonal features. Proliferation in the epithelium was comparable to controls and was significantly lower than in inflamed lesions. Numbers of CD3+, CD4+ T cells were elevated in the perifollicular and papillary dermis although levels were not equivalent to those in papules. The number of macrophages was also greatly increased and similar to those in papules. There were no changes in blood vessel numbers or vascular intercellular adhesion molecule 1 expression but E-selectin expression was increased to levels found in papules and vascular adhesion molecule 1 levels were upregulated. Levels of the pro-inflammatory cytokine interleukin-1 were also upregulated perifollicularly. Moreover, aberrant integrin expression was demonstrated in the epidermis around these uninvolved follicles and inflamed lesions whereas the basement membrane was still intact. These results provide novel evidence for vascular endothelial cell activation and involvement of inflammatory responses in the very earliest stages of acne lesion development.

Intracellular interleukin-1 receptor antagonist in osteoarthritis chondrocytes

The objective of the current study was to determine whether the balance of interleukin-1 and intracellular interleukin-1 receptor antagonist in chondrocytes in osteoarthritic human joints favors agonist action. Chondrocytes were isolated from cartilage specimens taken at the time of joint arthroplasty. Interleukin-1alpha, interleukin-1beta, and intracellular interleukin-1 receptor antagonist messenger ribonucleic acids were assessed by reverse transcriptase-polymerase chain reaction, and chondrocyte lysates were analyzed by enzyme-linked immunosorbent assay for the respective proteins. Type I intracellular interleukin receptor antagonist transcripts were the only intracellular variant detected in osteoarthritis chondrocytes. In cartilage graded as advanced osteoarthritis both interleukin proteins in chondrocyte lysates decreased, correlating with decreased interleukin-1alpha and beta messenger ribonucleic acids. Interleukin-1 receptor antagonist exceeded interleukin-1alpha in chondrocyte lysates by one order of magnitude except that in moderate osteoarthritis, antagonist was only two- to fourfold in excess. Interleukin-1alpha and interleukin-1beta proteins were correlated closely in individual lysates, with interleukin-1beta exceeding interleukin-1beta by one order of magnitude. In moderately degenerated cartilage, intracellular antagonist may not be sufficiently abundant to block postulated intracellular functions of precursor interleukin-1alpha. Furthermore, if stored interleukin-1alpha, interleukin-1beta, and interleukin receptor antagonist are released from chondrocytes, the localized antagonist would be insufficient to prevent signaling through cell surface receptors. Chondrocyte-derived interleukin-1alpha and interleukin-1beta may locally overwhelm inhibition by interleukin receptor antagonist to promote the early degenerative changes in osteoarthritis.

Interleukin-1beta does not contribute to genetic strain-based differences in iNOS expression and activity in chicken macrophages

The expression of IL-1beta and inducible nitric oxide synthase (iNOS) from iNOS hypo (GB2, B(6)B(6)) and hyper (K-strain, B(15)B(15)) responder chickens was examined. Compared to GB2, macrophages from K-strain expressed higher iNOS mRNA as quantitated by reverse transcriptase polymerase (RT-PCR) chain reaction after stimulation with 1 microgram/ml of Escherichia coli (E. coli) lipopolysaccharide (LPS). On the contrary, IL-1beta mRNA expression was comparable between K and GB2 macrophages at 3h post-LPS stimulation but persisted up to 9h only in GB2 macrophages. The LPS-inducible interleukin-1 (IL-1) surface receptor expression, measured by flow cytometry, was higher in GB2 than on K-strain macrophages. Blocking of IL-1 receptor by the anti-IL-1 receptor antibody reduced the LPS-mediated iNOS expression by 50% as quantified by competitive RT-PCR. Furthermore, iNOS activity (nitrite) was also reduced to 50%. However, this magnitude of inhibition was similar in both K and GB2 macrophages. While these observations suggest that IL-1beta is involved in mediating LPS-induced iNOS expression and activity, the differential response of GB1 and K-strain macrophages in terms of LPS-induced iNOS expression and activity is unlikely to be modulated by IL-1beta.

Tumor necrosis factor-alpha-converting enzyme: its role in community-acquired pneumonia

Bronchoalveolar lavage fluid recovered from infected and uninvolved lungs of patients with community-acquired pneumonia (CAP; n=16) on day 6+/-0.8 was analyzed for cytokine, soluble receptor, and antagonist levels. The role of tumor necrosis factor (TNF)-alpha-converting enzyme (TACE) in the resolution of the local inflammatory response was investigated. TNF-alpha, interleukin (IL)-1beta, and IL-6 were elevated in the infected versus uninvolved lobe, whereas IL-10 was not. Epithelial lining fluid (ELF) cytokine levels correlated with intracellular cytokine expression. Levels of proTNF-alpha were reciprocally related to TNF-alpha ELF levels. Levels of soluble receptors, generated by TACE cleavage of membrane-bound precursors, were compartmentalized to infected ELF. TACE was down-regulated by internalization in cells from the site of infection. These data demonstrate that, in vivo during CAP, TACE has a role in regulating resolution of the local inflammatory response by modulating levels of pro- and counterinflammatory mediators.

Interleukin-1 receptor immunoreactivity in sympathetic vascular and non-vascular neurons in guinea-pig coeliac ganglion

Immunoreactivity (IR) for the interleukin-1 receptor type I (IL1RI) was examined in sympathetic neurons in guinea-pig coeliac ganglion using multiple-labelling immunofluorescence. IL1RI-IR was present in 8% of sympathetic neurons in untreated preparations. The proportion of neurons with IL1RI-IR increased significantly after incubation in interleukin-6 (200 ng/ml) for 2-4 h (16-26% neurons), or after incubation for 4 h without cytokine (16%), with interleukin-1beta (IL1beta, 200 ng/ml; 18%) or tumour necrosis factor-alpha (200 ng/ml; 16%). This increase occurred predominantly in neuropeptide Y-IR, vasoconstrictor neurons. IL1RI-IR also was present in varicose axons, some of which projected from the gut, and in vascular smooth muscle cells and endothelium. These potential binding sites for the proinflammatory cytokine, IL1beta, on vasoconstrictor neurons and blood vessels may modulate sympathetic regulation of intestinal blood flow in inflammatory conditions.

Immunohistological analysis of thymoma by molecules differentially expressed in the thymic cortex and medulla, and its application in the differential diagnosis of thymoma from esophageal and lung cancer

The purpose of this study was to verify the WHO classification of thymic tumors using immunohistological methods, and to discover whether these methods can be applied to differentiate thymoma from squamous cell carcinoma (SCC) of the esophagus and the lung. Twenty-nine thymoma cases were classified according to WHO and were then immunohistologically examined for the positivity of these molecules. All thymoma cases investigated in this study were positive for IL-1R, and most of them were also positive for bek. In contrast, UH-1 was highly positive in B1 and B2 type thymomas, but negative or weakly positive in A, AB and B3 type thymomas. Twelve esophageal cancers and 21 lung cancers were also examined for the positivity of the same molecules. All esophageal cancers were negative for UH-1. Three of 12 cases were weakly positive for IL-1R, and four of these 12 cases were also weakly positive for bek. Twelve of 21 lung cancer cases were adenocarcinomas, all of them negative for IL-1R, bek and UH-1. Nine of 21 lung cancer cases were SCCs, all of them negative for UH-1. Eight of nine SCC cases were strongly positive for IL-1R, while seven of these were weakly positive for bek. We conclude that the WHO classification of thymic tumors is still valid as demonstrated by immunohistological analysis and that the positivity of UH-1, IL- 1R and bek might be helpful in differentiating thymoma from SCC of the esophagus and the lung.

Cytokine balance in the lungs of patients with acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) involves an intense inflammatory response in the lungs, with accumulation of both pro- and antiinflammatory cytokines in bronchoalveolar lavage fluid (BALF). Our goal was to determine how the balance between pro- and antiinflammatory mediators in the lungs changes before and after the onset of ARDS. We identified 23 patients at risk for ARDS and 46 with established ARDS and performed serial bronchoalveolar lavage (BAL). We used immunoassays to measure tumor necrosis factor alpha (TNF-alpha) and soluble TNF-alpha receptors I and II; interleukin 1 beta (IL-1 beta), IL-1 beta receptor antagonist, and soluble IL-1 receptor II; IL-6 and soluble IL-6 receptor; and IL-10. We used sensitive bioassays to measure net TNF-alpha, IL-1 beta, and IL-6 activity. Although individual cytokines increased before and after onset of ARDS, greater increases occurred in cognate receptors and/or antagonists, so that molar ratios of agonists/antagonists declined dramatically at the onset of ARDS. The molar ratios remained low for 7 d or longer, limiting the activity of soluble IL-1 beta and TNF-alpha in the lungs at the onset of ARDS. This significant antiinflammatory response early in ARDS may provide a key mechanism for limiting the net inflammatory response in the lungs.

Alteration of integrins by interleukin-1alpha in human pancreatic cancer cells

INTRODUCTION

Adhesion of tumor cells to extracellular matrix (ECM) proteins plays an important role in tumor invasion and metastasis.

AIMS

To investigate the expression of integrins in human pancreatic cancer cell lines and its alteration by interleukin (IL)-1alpha to examine the mechanism of adhesion of metastatic human pancreatic cancer cells to ECM proteins.

METHODOLOGY

The expression of integrin subunits and their alteration by IL-1alpha were examined by flow-cytometric analysis and cellular enzyme-linked immunosorbent assay in three metastatic human pancreatic cancer cell lines (AsPC-1, BxPC-3, and SW1990) and two nonmetastatic cancer cell lines (PaCa-2 and PANC-1). In addition, assays of cancer cell adhesion to ECM proteins were performed to investigate if increased integrin expression actually affected the adhesive interaction between cancer cells and the putative integrin ECM ligands.

RESULTS

The alpha(6) subunit expressed in metastatic cancer cells was enhanced by IL-1alpha. Metastatic cancer cells also showed preferential adherence to laminin compared with nonmetastatic cancer cells, and this was enhanced by IL-1alpha.

CONCLUSION

In pancreatic cancer, the enhancement of alpha(6)beta(1) integrin by IL-1alpha through IL-1 receptor type I, as well as the expression of alpha(6)beta(1) integrin, plays an important role in metastasis formation.

Cycle-dependent expression of interleukin-1 receptor type II in the human endometrium

Cytokines such as interleukin-1 (IL-1) play a major role in the reparative and inflammatory-like processes that occur in human endometrium during every menstrual cycle, but they also seem to be implicated in critical reproductive events such as ovulation and implantation. Interleukin-1 is tightly regulated in the body by a complex network of control systems. In the present study, we examined the expression of IL-1RII, a natural specific inhibitor of IL-1, in the human endometrium and found an interesting distribution and temporal pattern of expression throughout the menstrual cycle. Immunoreactive IL-1RII was found in stromal as well as epithelial cells, but it was predominant within the lumen of the glands and the apical side of surface epithelium. In situ hybridization and reverse transcription-polymerase chain reaction (RT-PCR) analyses showed higher levels of mRNA in epithelial than in stromal cells. The IL-1RII cellular and luminal secretion followed a regulated cycle phase-dependent pattern of expression. Although elevated in the late proliferative/early secretory phase of the menstrual cycle, IL-1RII luminal secretion significantly decreased in the midsecretory phase, reaching its lowest levels at Day 21, before augmenting markedly again during the late secretory phase. This pattern of expression was less obvious at the level of cellular staining, as examined by immunohistochemistry, but it was corroborated by Western blot analysis of IL-1RII protein and semiquantitative RT-PCR of IL-1RII mRNA in the whole endometrial tissue and separated glandular epithelial cells. The reduced expression of IL-1RII within the implantation window suggests the existence of accurate regulatory mechanisms that, by down-regulating IL-1RII expression, alleviate IL-1 inhibition during this crucial period and facilitate IL-1 proimplantation actions. The elevated expression of IL-1RII observed during the late secretory phase suggests an involvement of IL-1RII in control of the proinflammatory state that takes place in the endometrium during the premenstrual and menstrual periods.

Synovial fluid cytokine levels in Behçet's disease

OBJECTIVE

To investigate the synovial fluid levels of interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), IL-1 receptor antagonist (IL-1ra), soluble IL-2 receptor (sIL-2r) and IL-8 in patients with Behçet's disease (BD) and to compare them to levels in rheumatoid arthritis (RA), and osteoarthritis (OA).

METHODS

The cytokine levels of BD (n = 14), RA (n = 15) and OA (n = 15) patients were assessed by enzyme-linked immunosorbent method.

RESULTS

Median synovial IL-1 beta and TNF-alpha levels were higher in RA compared to BD and OA patients. IL-1 beta levels were also higher in BD than OA whereas TNF levels were similar in these two groups. IL-1ra and TGF-beta activity in BD were higher than OA but lower than RA. sIL-2r and IL-8 levels were increased in BD and RA in comparison to OA patients.

CONCLUSION

The arthritis of BD is non-erosive and accordingly, its synovial fluid contains lower levels of cytokines primarily involved in cartilage destruction, namely IL-1 beta and TNF-alpha, than RA. IL-1ra and TGF might serve as protective factors against erosion in the inflamed joints. High synovial fluid levels of sIL-2r and IL-8 probably reflect a non-specific inflammatory process.

Epidermal growth factor inhibits 8-Br-cAMP-induced decidualization of human endometrial stromal cells

The effects of epidermal growth factor (EGF) on human endometrial stromal cells have not been characterized well, although production of EGF in endometrial epithelial and stromal cells and expression of EGF receptors in endometrial stromal cells have been reported. We investigated the effects of EGF on endometrial cell viability, 8-Br-cAMP-induced stromal decidualization, and prolactin secretion from decidualized endometrial stromal cells using an in vitro decidualization activity assay of human endometrial stromal cells. EGF did not show any significant effects on viable cell numbers of nondecidualized and 8-Br-cAMP-induced decidualized cells. Prolactin release from the 8-Br-cAMP-induced decidualized cells was not affected by EGF. However, EGF dose-dependently inhibited prolactin release from the stromal cells that were in the process of decidualization by co-stimulation with 8-Br-cAMP and EGF, though there was no significant change in viable cell numbers of the 8-Br-cAMP-stimulated decidualizing cells. Flow cytometric analysis revealed that 8-Br-cAMP enhanced EGF receptor expression on the endometrial stromal cells. These results indicate that endometrial EGF inhibits decidualization through autocrine/paracrine mechanisms.

Human milk anti-inflammatory component contents during acute mastitis

Mastitis is a common complication of human lactation. We examined milk specimens from eight women with clinical mastitis to determine their content of anti-inflammatory components. Antioxidant activity (spontaneous cytochrome c reducing activity), selected pro-inflammatory cytokines (IL-6, IL-1beta), selected endogenous cytokine control molecules (sIL-6R, sIL-1RII, and sTNFRI), lactoferrin, Na(+):K(+) ratios, and milk bioactivities that cause shedding of sIL-1RII from human polymorphonuclear leukocytes (PMN), suppress PMN aggregation, and suppress PMN adherence responses were not increased compared to normal milks. Neither the bioactivities that deplete PMN intracellular Ca(2+) stores nor those that block Ca(2+) influx into fMLP-stimulated PMN were significantly increased in mastitis milks. In contrast, levels of TNFalpha, sTNFRII, and IL-1RA and bioactivities that cause shedding of sTNFRI from human PMN were significantly increased compared to normal milks. Mastitis milk has the same anti-inflammatory components and characteristics of normal milk, with elevations in selected components/activities that may help protect the nursing infant from developing clinical illness due to feeding on mastitis milk.

The inflammatory response following delivery is amplified in women who previously suffered from major depression, suggesting that major depression is accompanied by a sensitization of the inflammatory response system

BACKGROUND

There is now evidence that some patients with major depression show an activation of the inflammatory response system (IRS). This study was carried out to examine whether major depression may induce sensitization with increased IRS responses to the stress of child birth.

METHODS

Serum concentrations of interleukin-6 (IL-6), the soluble IL-6 receptor (sIL-6R), sgp130 (the IL-6 signal transducing protein) and the sIL-1R antagonist (sIL-1RA) were determined in 16 and 50 women with and without a lifetime history of major depression, respectively. Blood was collected 3-6 days before delivery and 1 and 3 days after delivery. On each occasion the women completed the Zung Depression Rating Scale (ZDS).

RESULTS

Serum IL-6, sIL-6R, sIL-1RA were significantly higher 1 and 3 days after delivery than before. Women who had suffered from a lifetime history of major depression had greater increases in serum IL-6 and sIL-1RA in the early puerperium than women without a lifetime history. Women who had suffered from a lifetime history of major depression had significantly higher IL-6, and sIL-1RA concentrations 1 and 3 days after delivery than women with a negative life-time history.

CONCLUSIONS

The responses of IL-6 and sIL-1RA following delivery are amplified in women who previously suffered from major depression. The results suggest that major depression is accompanied by a sensitization of the IRS.

Age-related regional difference of interleukin-1 expression in rat brain after lipopolysaccharide treatment

Aging is associated with altered immune responses including dysregulation of cytokine production. Of cytokines, interleukin-1 (IL-1) family has been primarily involved with central nervous system. To evaluate the age-related different response of IL-1 family following peripheral administration of lipopolysaccharide (LPS), immunohistochemical study of IL-1beta and IL-1 receptor expression was performed on Sprague-Dawley rat brain. Experimental animals were divided into four groups; saline-treated young (3-5 months) and old (over 24 months), and LPS-treated young and old groups. After intraperitoneal (i.p.) injection of LPS, three to five rats within each group were killed at 1, 2, 4, 8 and 16 hr. After fixation in 4% neutral buffered formalin, the brain slices were paraffin-embedded. Immunohistochemical staining using labelled streptavidin biotin was performed. The results showed that IL-1beta immunoreactivity was seen in the endothelial cell of pons in both LPS-treated young and old rats, with slightly longer persistency in old group. IL-1RI immunoreactivity appeared initially in the neurons of cerebral cortex in LPS-treated old group, compared with predominantly the cerebellum in LPS-treated young group. In conclusion, our study shows that there is age-related, different neuronal localization of IL-1RI expression at different points of time after LPS treatment.

Interleukin-1 receptor antagonist in ascites indicates acute graft rejection after pediatric liver transplantation

Acute graft rejection is one of the most frequent complications after pediatric liver transplantation (LTx). In clinical practice, it is sometimes difficult to differentiate acute cellular graft rejection from other complications because clinical and chemical findings are often nonspecific. We therefore investigated the value of cytokine quantification in drained ascites, in addition to quantification of cytokine concentrations of serum, in 30 children in the first 2 weeks after orthotopic liver transplantation (OLT). Six of 30 patients showed acute graft rejection, with rising levels of alanine aminotransferase (ALT) and alpha-glutathione-S-transferase (alpha-GST) in serum up to 24 h prior to biopsy-proven rejection. There were no significant elevations of interleukin-2 receptor (IL-2r) and interleukin-6 (IL-6) in serum and ascites. In contrast to these findings, the concentration in ascites of the interleukin-1 receptor antagonist (IL-1ra) increased 48 h before rejection was proven by liver biopsy (p < 0.01, in comparison with the non-rejecting group, n = 24). The IL-1ra concentration in ascites was up to 11-fold higher than in serum during rejection (15.43 vs. 1.38 ng/mL). Two children with early infectious complication showed no significant increase in ascitic IL-1ra concentration. We conclude from these data that quantification of IL-1ra in ascites indicates the start of graft rejection after LTx. As long as abdominal drainage is performed, this non-invasive procedure may be of additional value in differential diagnoses and early diagnosis of rejection.

Interleukin-1 receptor antagonist expression in human endothelial cells and atherosclerosis

The proinflammatory cytokine interleukin (IL)-1 is expressed mainly within the endothelium of atherosclerotic plaques and may be linked with inflammatory mechanisms of atherogenesis. IL-1 action is complex and regulated in part by its naturally occurring inhibitor, the IL-1 receptor antagonist (IL-1ra). Therefore, we studied differential and specific isoform expression of IL-1ra in the endothelium of diseased coronary arteries and in endothelial cells (ECs) stimulated under defined conditions. In view of an association with IL-1ra gene (IL-1RN) polymorphism, the influence of endothelial cell genotype at IL-1RN on IL-1ra protein production was also examined. Secreted IL-1ra and intracellular IL-1ra mRNAs were detected by semiquantitative reverse transcription-polymerase chain reaction in human atherosclerotic and dilated cardiomyopathic coronary arteries; protein expression appeared increased in atherosclerotic compared with dilated cardiomyopathic arteries, where IL-1ra appeared to be confined to the endothelium. Only intracellular IL-1ra type I mRNA was detected in human umbilical vein ECs (HUVECs) and human coronary artery ECs (HCAECs) when they were stimulated with bacterial lipopolysaccharide/phorbol myristate acetate and transforming growth factor-beta. IL-1beta and IL-1alpha were without effect. IL-1ra protein was detected in HUVECs (intracellular IL-1ra), HCAECs (intracellular IL-1ra), and human coronary artery smooth muscle cells (intracellular IL-1ra) by immunoprecipitation and Western blot. IL-1ra was detected in HUVEC cell lysates by ELISA and appeared to be influenced by the genotype of the IL-1RN variable number tandem repeat, an 86-bp repeat polymorphism in intron 2 of the IL-1ra gene, with lower levels of IL-1ra produced by IL-1RN allele 2-containing cells (ratio of IL-1ra to total protein: for 1,1 homozygotes, 1.38+/-0.28x10(-9) [n=15]; for 1,2 heterozygotes, 0.81+/-0.17x10(-9) [n=8]; and for 2,2 homozygotes, 0.63+/-0.19x10(-9) [n=5]; P<0.05 compared with 1,1 homozygotes). This is the first demonstration of IL-1ra in human diseased arteries, stimulated HUVECs, and HCAECs and indicates the endothelial cell as an important source. Endothelial IL-1ra production may be controlled by the endothelial IL-1RN genotype. These data further support the role of the IL-1 system of cytokines in the pathogenesis of atherosclerosis.

Effects of early inhaled beclomethasone therapy on tracheal aspirate inflammatory mediators IL-8 and IL-1ra in ventilated preterm infants at risk for bronchopulmonary dysplasia

We tested the hypothesis that inhaled beclomethasone therapy for prevention of bronchopulmonary dysplasia (BPD) reduces pulmonary inflammation. As part of a randomized, placebo-controlled trial, interleukin-8 (IL-8) and interleukin-1 receptor antagonist (IL-1ra) concentrations in tracheal aspirates were measured as markers of pulmonary inflammation. On study days 1 (baseline), 8, 15, and day 28 of age, samples were obtained from enrolled infants (birth weights <1,251 g, gestational age <33 week, 3 to 14 days of age) who remained ventilated and had not received systemic glucocorticoid therapy. Cytokine levels (pg/microg of free secretory component of immunoglobulin A) were compared between groups. We determined whether baseline cytokine levels modified treatment effect regarding subsequent need for systemic glucocorticoid therapy or occurrence of BPD (age 28 days). Tracheal aspirates were obtained from 161 infants (77 receiving beclomethasone, 84 receiving placebo). Median IL-8 levels were lower in beclomethasone versus placebo infants on study days 8 (82.9 vs. 209.2, P < 0.01) and 15 (37.4 vs. 77.4, P < 0.03) after controlling for antenatal glucocorticoid therapy and maternal race. Median IL-1ra levels were lower in beclomethasone versus placebo infants only on study day 8 (86.5 vs. 153.3, P < 0.01). Fewer beclomethasone infants with baseline IL-8 levels in the interquartile range required systemic glucocorticoid therapy (beclomethasone 30.6% vs. placebo 65.8%, P < 0.01) or developed BPD (beclomethasone 42.4% vs. placebo 69.4%, P < 0.03). We conclude that early-inhaled beclomethasone therapy was associated with a reduction in pulmonary inflammation after 1 week of therapy. Beclomethasone-treated infants with moderately elevated baseline IL-8 levels received less subsequent systemic glucocorticoid therapy and had a lower incidence of BPD than nontreated infants.

Induction of intracellular interleukin-1 beta signals via type II interleukin-1 receptor in human gingival fibroblasts

The type II interleukin-1 receptor (IL-1RII) has been thought to be incapable of transducing signals to cells because of its short intracellular domain, while type I IL-1 receptor (IL-1RI) does transduce signals. Since over-expression of IL-1RII has been demonstrated to inhibit cytokine production in the fibroblastic cell line, it has been proposed to use IL-1RII to prevent IL-1-induced inflammation in connective tissue. In this study, trace amounts of IL-1RII mRNA expression were detected in human gingival fibroblasts (HGFs), which are affected by cytokines in inflammatory periodontal disease. Cloning of the cDNA encoding IL-1RII expressed in HGFs revealed 3 amino acid substitutions in the extracellular domain, when compared with the 408 residues predicted from human B-cells. Over-expression of IL-1RII on HGFs by gene transfer down-regulated the expression of IL-1 beta mRNA and IL-6 mRNA in response to IL-1 beta stimulation, while the expression of IL-8 mRNA was not affected. In the IL-1RII-transfected HGFs, phosphorylation of 25- and 74-kDa proteins was up-regulated upon IL-1 beta stimulation in the transfected HGFs. The phosphorylation of these proteins was suppressed by the addition of a neutralizing antibody against IL-1RII. These results suggest that the IL-1RII may regulate HGFs expression of cytokine mRNA upon IL-1 beta stimulation, possibly by altering the IL-1RI-dependent signals.

ELISA for bovine interleukin-1 receptor antagonist and its application to mastitic sera and whey

A sandwich ELISA for the bovine IL-1 receptor antagonist (bIL-1ra) was developed using recombinant (r) bIL-1ra produced by Escherichia coli, anti-rbIL-1ra rabbit IgG, its biotinylated one and avidin-peroxidase. This ELISA system enabled detection of rbIL-1ra at a concentration of more than 2 ng/ml. This ELISA was applied to quantitation of bIL-1ra in sera and whey of mastitic and healthy cows. The results indicate that although IL-1ra levels in healthy and mastitic sera and whey were comparable, serum IL-1ra/IL-1beta ratio of euthanized cows was significantly lower than that of the recovered.