Inhibition of tumor necrosis factor-alpha attenuates wound breaking strength in rats.

Exogenous administration of tumor necrosis factor-alpha has been shown to both enhance and attenuate cutaneous healing in a dose-dependent manner. We examined the effects of tumor necrosis factor inhibition in the healing wound by both systemic and local administration of tumor necrosis factor-binding protein. Male Balb/C mice underwent dorsal skin incision with subcutaneous implantation of 20 mg polyvinyl alcohol sponges (4 per animal). In Experiment I, one group (n = 20) received intraperitoneal injections of tumor necrosis factor-binding protein (3 mg/kg) at the time of wounding, while another group (n = 20) received saline. Four animals from each group were euthanized on days 1, 3, 5, 7, and 14 postwounding. In Experiment II, one group (n = 10) received an intraperitoneal injection of tumor necrosis factor-binding protein (3 mg/kg) at the time of wounding and every third day thereafter. Another group (n = 10) received an intraperitoneal injection of saline at the time of wounding and every third day thereafter. In Experiment III, one group received a single intraperitoneal injection of tumor necrosis factor-binding protein (3 mg/kg) at the time of wounding (n = 7), or on postwounding day 4 (n = 7), or day 7 (n = 7). Another group received saline injections at the time of wounding (n = 7), or on postwounding days 4 or 7 (n = 7, respectively). All animals in Experiments II and III were killed at postwounding day 14. Wound breaking strengths were assessed using a tensiometer. Wound fluid collected from the implanted sponges was assayed for tumor necrosis factor-alpha and tumor necrosis factor-binding protein levels using a biological assay and enzyme-linked immunosorbent assay, respectively. Collagen gene expression in sponge granulomata was assessed by Northern analysis. Collagen deposition in sponges was quantified by measuring hydroxyproline content. Wounds were significantly weaker in the animals that received repeated injections of tumor necrosis factor-binding protein with a mean wound breaking strength of 93.1 g vs. 186.6 g in controls (p < 0.05). Wound breaking strength in groups that received a single injection of tumor necrosis factor-binding protein on either day 0, 4, or 7 postwounding were no different than their respective controls. There was no difference in the mean hydroxyproline content of sponges between any of the tumor necrosis factor-binding protein groups and their respective controls. Northern analysis for collagen I and III expression also revealed no differences. These data indicate that continued systemic administration of tumor necrosis factor-binding protein resulted in significantly weaker wounds with no corresponding differences in wound collagen content, and collagen gene expression. This suggests that tumor necrosis factor-alpha inhibition throughout healing leads to a qualitatively impaired wound without a quantitative alteration in collagen deposition.     

Interleukin-1 receptors and receptor antagonist in haemodialysis

Background. Biological activity of interleukin-1 (IL-1) depends on the number and type of IL-1 receptors on target cells and on the amounts of its naturally occurring inhibitor, the IL-1 receptor antagonist (IL-1ra). Methods. Expression of IL-1 receptor was studied on the peripheral blood mononuclear cells of 20 end-stage renal-disease patients maintained by chronic haemodialysis by means of either polysuphone (10 patients) or cuprophane membranes (10 patients) and compared to that of normal controls. Plasma and cellular levels of IL-1ra and IL-1{beta} were also measured. Results. The proportion of monocytes expressing the IL-1 receptor was strikingly higher in haemodialysis patients than in the healthy population. This proportion further increased during haemodialysis with cuprophane but not with polysulphone. Expression of the IL-1 receptor on lymphocytes was very low in both controls and dialysed patients; in the latter there was no intradialytic variation. Plasma concentrations of IL-1{beta} and IL-1ra were elevated in haemodialysis patients and undetectable in controls. Whereas plasma IL-1{beta} decreased throughout haemodialysis, IL-1ra further increased, with no significant differences between the two membranes used. Total cellular IL-1{beta} and IL-1ra were also higher in the patient group than in the healthy controls. A further increase of both IL-1{beta} and IL-1ra was detected at the end of the haemodialysis session with any membrane. Conclusion. Monocytes of haemodialysis patients circulate in a state of activation, which makes them both producer and target of IL-1. Thus there is an autocrine upregulation of IL-1. Although IL-1ra levels are high, they are most likely to be expression of monocyte activation rather than represent effective inhibitors of IL-1 activity.     

Effects of tumor bearing and protein depletion on wound breaking strength in the rat.

Investigations into the effects of tumor bearing and protein depletion on wound breaking strength (WBS), serum protein content, and scar collagen production were performed in the rat. Animals were fed either regular diet (RD) or protein-depleted diets (PD) prior to or following wounding. Animals fed PD postwounding consistently lost weight, had reduced WBS, lower serum proteins, and reduced scar [³H]hydroxyproline content at 14 and 21 days whether they were on RD or PD diets prewounding. Animals fed PD prewounding and RD following wounding approached control values of WBS and scar [³H]hydroxyproline content by 21 days. Tumor bearing (TB) animals on RD manifested weight loss, reduced WBS, and hypoproteinemia by Day 21, compared to non-tumor (NTB) animals on RD but fed to pair the carcass weight of TB animals. In order to achieve comparable reductions in WBS and serum albumin levels seen in TB animals, we imposed severe metabolic restrictions on NTB animals by PD diets. This eventuated in weight loss two times greater than the TB animals as well as hypoproteinemia. Reductions in WBS were accompanied by wound compliance changes suggesting decreased compliance in TB animals.     

Impact of interleukin-1 receptor antagonist and tumor necrosis factor-alpha gene polymorphism on IgA nephropathy

BACKGROUND: It is evident that cytokines play an important role in the pathogenesis as well as disease progression in IgA nephropathy (IgAN). The level of cytokine production is influenced by different genotypes that reflect gene polymorphism of the pertinent cytokine. Interleukin-1 receptor antagonist (IL-1ra) and tumor necrosis factor-alpha (TNF-alpha) gene polymorphism have been found to affect disease susceptibility and activity in several inflammatory diseases. However, the impact of these polymorphisms in IgAN patients has not previously been thoroughly studied. METHODS: We investigated 111 cases of biopsy-proven IgAN and 100 healthy, normal controls for their IL-1ra and TNF-alpha gene polymorphism. IL-1ra gene polymorphism was characterized as a variable number of tandem repeats of a 86 bp sequence within intron 2. Five alleles were identified and were designated as IL1RN*1, IL1RN*2, IL1RN*3, IL1RN*4, and IL1RN*5, corresponding to 4, 2, 5, 3, 6 repeats, respectively. A polymorphism in the promoter region of the TNF-alpha gene was also studied. This polymorphism involved a guanidine to adenosine transition at position -308 and was designated as TNF1 (-308G) and TNF2 (-308A). RESULTS: There were 54 male and 57 female patients with a mean age of 30.3 +/- 12.5 years and a disease duration of 66. 8 +/- 47.2 months. The mean duration of the follow-up period was 47. 3 +/- 32.6 months. In the patient group, the allele frequencies of IL1RN*1, IL1RN*2, IL1RN*3, IL1RN*4, and IL1RN*5 were 89.6%, 9.9%, 0%, 0.5%, and 0%, respectively, whereas the corresponding carriage rates were 100%, 19.8%, 0%, 0.9%, and 0%, respectively. An excessive carriage of IL2RN*2 was found in the patients when compared with normal controls (allele frequency, 9.9 vs. 2.5%, P < 0.0001). The allele frequencies of TNF1 and TNF2 were 94.1 and 5.9%, respectively, and the carriage rates were 99.1 and 10.8%, respectively, in the patients, which was not significantly different from those of normal controls. When the patients were stratified into mild and severe groups according to their initial presentation, none of the studied alleles correlated with the severity. However, patients with gross hematuria were associated with a higher carriage rate of TNF2 when compared with patients without gross hematuria (allele frequency, 15. 4 vs. 4.6%, P = 0.0552; carriage rate, 30.8% vs. 8.2%, P = 0.0272). Renal survival analysis revealed that the TNF2 carrier had a renal survival comparable with TNF2 (-) patients. However, the carriage of the IL1RN*2 allele was associated with a significantly poorer long-term outcome with a median survival time of 72 months, as compared with those without IL1RN*2 (134 months, P < 0.01). CONCLUSION: IL-1ra and TNF-alpha gene polymorphism may affect disease susceptibility as well as disease activity and long-term outcome in human IgAN. Treatment with an IL-1ra or IL-1 blocking agent may be relevant in those carrying the IL1RN*2 allele.     

Interleukin 1 receptor antagonist and tumor necrosis factor-alpha gene polymorphism in patients with end-stage renal failure

End-stage-renal disease (ESRD) is a final result of various etiologies. Prognostic indicators leading to ESRD in chronic kidney diseases have been studied extensively, of which, genetic factors remain a subject of great concern. Interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) are potent proinflammatory cytokines that are involved in several chronic kidney diseases. Studies on cytokine gene polymorphism have revealed important information about the role of genetic factors in disease susceptibility and severity. Gene polymorphism of interleukin-1 receptor antagonist (IL-1ra) and TNF-alpha were determined in 297 ESRD patients and in 145 normal healthy controls. IL-1ra gene polymorphism was characterized as a variable number of tandem repeats of a 86 bp sequence within intron 2. Five alleles were identified and were designated as IL1RN*1, IL1RN*2, IL1RN*3, IL1RN*4, and IL1RN*5, corresponding to 4,2,5,3, and 6 repeats, respectively. A polymorphism in the promoter region of the TNF-alpha gene was also studied. This polymorphism involved a guanidine to adenosine transition at position -308 and was designated as TNF1 (- 308 G) and TNF2 (-308 A). The genotypes and allele frequencies were compared between patients and control group. The distributions of genotypes of IL-1ra and TNF-alpha did not differ significantly between ESRD patients and normal controls. Analysis of allele frequencies revealed a trend toward an increase in IL1RN*2 frequency (7.5% versus 3.8 %, p=0.064) and noncarriage of TNF2 in the patient group (7.2% versus 11.0%, p=0.076) when compared with the control group. When both alleles were considered together, the patient group had a significantly higher frequency of carriage of IL1RN*2 in combination with noncarriage of TNF2 (p=0.0468). We conclude that carriage of IL-1RN*2 and noncarriage of TNF2 allele appear to be poor prognostic factors in patients suffering from various chronic renal diseases that eventually enter end-stage renal failure.     

Interleukin-1 beta and tumor necrosis factor-alpha in normal/infertile men

Cytokines play an important role in intercellular communications. Human sperm contains a wide spectrum of cytokines. such as interleukin-1 beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha). Their effects on semen quality are subject to debate. The aim of this study was to determine concentrations of IL-1beta and TNF-alpha in normal fertile men and in different groups of male infertility in an attempt to clarify the physiology and suggest possible clinical uses. Sixty-six subfertile male patients with varicocele (n = 22). infection of accessory genital glands (n = 14), varicocele plus infection (n = 4), chronic epididymitis (n = 8). post-renal transplantation status (n = 5), idiopathic oligoasthenoteratospermia (n = 9), cryptorchidism (n = 1), and homozygous beta-thalassemia (n = 3) as well as 5 male controls were studied through history, physical examination, spermiograms, plasma basal hormonal levels, and IL-1beta and TNF-alpha levels in seminal fluid. There was no significant statistical difference regarding IL-1beta and TNF-alpha among fertile men and subfertile patients of any cause. 1L-1beta and TNF-alpha were in tight positive correlation (p<.001). Determination of IL-1beta and TNF-alpha does not provide useful information in male routine infertility workup. Nevertheless, a better understanding of these mediators in semen of normal men and infertile patients may contribute to a new approach to the management of male infertility.     

Interleukin-1 beta and tumor necrosis factor-alpha release in normal and diseased human infrarenal aortas.

The presence of chronic inflammatory cells in the adventitia and media of abdominal aortic aneurysms and aortic occlusive disease suggest an immunologic response. The purpose of this study is to determine whether normal or diseased infrarenal aortas liberate the inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta). Twenty-six infrarenal aortic biopsies (5 aortic occlusive disease, 15 abdominal aortic aneurysms, and 6 cadaveric donors) were weighed, minced into small pieces, and incubated in media for 48 hours. Conditioned media was harvested at 48 hours and assayed for IL-1 beta or TNF-alpha with use of an ELISA assay. Comparison of groups was performed with a one-way analysis of variance. The constitutive IL-1 beta produced by abdominal aortic aneurysms was significantly different than that in cadaveric donors (908 +/- 194 pg/ml [SE] vs 100 +2- 30 pg/ml). There was no statistically significant difference between abdominal aortic aneurysms and aortic occlusive disease (908 +/- 194 pg/ml vs 604 +/- 256 pg/ml) or aortic occlusive disease and cadaveric donor (604 +/- 256 vs 100 +/- 30). In time-course studies for the release of IL-1 beta, abdominal aortic aneurysms demonstrated maximal release at 48 hours. IL-1 beta release was augmented by lipopolysaccharide in all categories. A dose response curve demonstrated maximal IL-1 beta release on stimulation with 5 micrograms/ml LPS. Constitutive TNF-alpha production was low, ranging from 13 +/- 1.5 pg/ml in cadaveric donor, to 20 pg/ml in aortic occlusive disease, and 24 +/- 11 pg/ml in abdominal aortic aneurysms. There was no augmentation in TNF-alpha with lipopolysaccharide.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evidence for tumor necrosis factor-induced pulmonary microvascular injury after intestinal ischemia-reperfusion injury.

Acute lung injury characterized by increased microvascular permeability is one feature of multiple-organ system failure and the adult respiratory distress syndrome. Intestinal ischemia-reperfusion injury has been linked to this type of acute lung injury. The purpose of these experiments was to examine the pathogenic mediators that link the two processes, with particular emphasis on the roles of endotoxin and tumor necrosis factor alpha (TNF alpha). Previously described characteristics of the acute lung injury in this rat model of intestinal ischemia-reperfusion include pulmonary neutrophil sequestration, depletion of lung tissue ATP, alveolar endothelial cell disruption, and increased microvascular permeability. Plasma levels of TNF in the systemic circulation of sham-operated animals and those with intestinal ischemic injury less than 60 minutes in duration were very low or undetectable. Intestinal ischemia for 120 minutes was associated with TNF elevation to 1.19 +/- 0.50 U/mL. Reperfusion for periods of 15 and 30 minutes generated 5- to 10-fold increases in circulating TNF levels (6.61 +/- 3.11 U/mL, p greater than 0.05 and 10.41 +/- 5.41 U/mL, p = 0.004 compared to sham); however this increase in circulating TNF was transient and largely cleared within 60 minutes after initiating reperfusion. Portal vein endotoxin levels were found to increase significantly before the appearance of TNF in systemic plasma, suggesting that gut-derived endotoxin may induce TNF release from hepatic macrophages into the systemic circulation. Anti-TNF antibody attenuated the increase in pulmonary microvascular permeability in this preparation but did not prevent pulmonary neutrophil sequestration. These observations suggest that endotoxin and TNF have pathogenic roles in this acute lung injury, but that mechanisms of adherence of neutrophils to endothelial cells independent of TNF may be involved. The accumulation of neutrophils in the lung but the prevention of a vascular permeability increase in the presence of antibody to TNF may imply an in vivo role for TNF in the process of neutrophil activation. These studies provide additional evidence of the importance of the endogenous inflammatory mediators in the development of systemic injury in response to local tissue injury.     

Interleukin-1alpha gene expression during wound healing.

Interleukin-1alpha is known to be constitutively produced by epidermal keratinocytes under normal conditions, and injection of this cytokine enhances wound reepithelialization. However, no studies have characterized the temporal sequence of interleukin-1alpha gene expression over the time course of wound healing, and the cellular sources of this cytokine have not been identified. In the present studies, levels of interleukin-1alpha messenger RNA in wound tissue isolated from SKH-1 hairless mice were characterized and the cells that produced interleukin-1alpha immunoreactive protein over a 10-day time course of wound healing were defined. A time-dependent upregulation in interleukin-1alpha gene expression occurred immediately (4 hours) after a full-thickness wound was made, which represented a four-fold increase over levels of cytokine gene expression detected in nonwounded skin. Upregulation of cytokine gene expression correlated with an immediate increase in plasma interleukin-1alpha levels and was followed by an increase in interleukin-1alpha immunoreactive protein localized to keratinocytes within the leading edge of the wound and epidermis, as well as to neutrophils within the dermis. The rapid increase in local and systemic interleukin-1alpha levels correlated with the infiltration of a significant number of neutrophils into the wound site and with the proliferation of both basal keratinocytes and dermal fibroblasts. Given the known ability of interleukin-1alpha to regulate proliferation and migration of epidermal keratinocytes and to indirectly induce leukocyte chemotaxis, the results of the present studies suggest that interleukin-1alpha may be an important cytokine with both local and systemic actions that are linked to the initiation of critical cellular events early in wound healing.     

Interleukin-1 receptor antagonist as a biomarker for bronchiolitis obliterans syndrome in lung transplant recipients

BACKGROUND: The major limitation to survival after lung transplantation is bronchiolitis obliterative syndrome (BOS). BOS is a chronic inflammatory/immunologic process characterized by fibroproliferation, matrix deposition, and obliteration of the airways. The mechanism(s) that lead to fibro-obliteration of allograft airways have not been fully elucidated. Interleukin-1 receptor antagonist (IL-1Ra) is a naturally occurring antagonist of the pro-inflammatory cytokine IL-1 and has been associated with a number of fibroproliferative diseases. METHODS: We determined whether IL-1Ra, as compared to IL-1beta, IL-10, transforming growth factor (TGF)-beta, and tumor necrosis factor (TNF)-alpha, in the bronchoalveolar lavage fluid (BALF) from lung transplant recipients was associated with BOS. BALF was collected from three groups of patients: BOS (n=22), acute rejection (n=33), and healthy transplant recipients (n=30). RESULTS: IL-1Ra levels were significantly elevated in patients with BOS compared to healthy lung transplant recipients and patients with acute rejection (P<0.001 and P<0.05, respectively). Furthermore, when patients with BOS had their BALF analyzed from their last bronchoscopy before the development of BOS (Future BOS [FBOS] group) (n=20), their levels of IL-1Ra were also significantly elevated compared to healthy lung transplant recipients and patients with acute rejection (P<0.001 and P<0.05, respectively). Importantly, the elevated levels of IL-1Ra in the BOS and FBOS groups were not accompanied by any significant increases in IL-1beta, IL-10, TGF-beta, or TNF-alpha. CONCLUSION: These findings suggest that elevated levels of IL-1Ra may be attenuating IL-1 bioactivity during the pathogenesis of BOS and creating a local environment that favors fibroproliferation and matrix deposition.     

白介素-1受体桔抗剂对实验性新月体肾炎骨调素表达的调节作用

目的探讨白介素-1受体拮抗剂（IL-lra）对实验性新月体肾炎肾脏组织骨调素（OPN）表达的调节作用，进一步阐明IL-1在实验性新月体肾炎发病机制中的作用。方法加速型实验性新月体肾炎模型应用兔抗鼠肾小球基底膜肾毒血清制备。第1组为模型组：注射肾毒血清后第0～7天，不加任何干扰治疗；另外2组为治疗组及治疗对照组：从第7～14天，分别给予IL-lra和生理盐水持续静脉点滴。结果模型组OPN的表达显著增高。生理盐水治疗组，OPN在肾小球和小管-间质细胞的表达更高，并和巨噬细胞的局部浸润及肾功能密切相关。而IL-lra治疗组，OPN的表达显著下调，巨噬细胞浸润明显减少，部分逆转肾功能。结论应用IL-lra抑制IL-1的活性可显著下调骨调素的表达和保护肾功能，提示IL-lra的治疗作用可能是通过抑制骨调素的表达，减少巨噬细胞在肾脏局部浸润的机制。     

Growth hormone attenuates tumor necrosis factor alpha in burned children

BACKGROUND: Recombinant human growth hormone (rhGH) has been shown to favorably modulate the acute-phase response and may improve the clinical outcome. OBJECTIVE: To examine whether rhGH attenuates the elevated tumor necrosis factor alpha (TNF-alpha) levels that correlate with increased multiorgan failure and mortality in burned adults and children. DESIGN: Twenty children with burns of greater than 40% of the total body surface area were randomly divided into 2 groups to receive placebo (n = 10) or rhGH, 0.2 mg/kg per day intramuscularly (n = 10). SETTING: Pediatric burn hospital. MAIN OUTCOME MEASURE: Serum TNF-alpha levels by enzyme-linked immunoassay at baseline (day 0) and at 21 and 42 days after injury. For statistical analysis, we used the Kruskal-Wallis and Friedman tests. RESULTS: No significant differences in age (mean +/- SD, 6.2+/-1.6 vs 5.0+/-1.2 years) or percentage of total body surface area burn (mean +/- SD, 65.1%+/-8.2% vs 57.1%+/-5.2%) could be shown between the groups given rhGH and placebo. Baseline TNF-alpha levels were elevated from reference values in both groups. Twenty-one and 42 days after rhGH administration, serum TNF-alpha levels were significantly decreased from those at baseline (P<.05). No significant decrease in TNF-alpha levels was observed in the placebo group (P = .5). CONCLUSIONS: Recombinant human growth hormone significantly lowers serum TNF-alpha levels after burn injury. This is consistent with the beneficial effect that rhGH has on the acute-phase response.     

Interleukin-1 and tumor necrosis factor stimulate the formation of human osteoclastlike cells in vitro

Interleukin-1 (IL-1) alpha and beta and tumor necrosis factor (TNF) alpha and beta are potent stimulators of bone resorption in vitro and in vivo. However, the mechanisms underlying this increased bone resorption have not been clearly defined. Increased bone resorption can result from increased activity of individual osteoclasts, increased numbers of osteoclasts, or both. Therefore, we have used a long-term human marrow culture system that forms multinucleated cells (MNC) with the characteristics of osteoclasts to examine the effects of IL-1 and TNF on osteoclast formation. Human recombinant IL-1 alpha and IL-1 beta, and human recombinant TNF-alpha and TNF-beta stimulated MNC formation from 4- to 60-fold. IL-1 alpha, IL-1 beta, TNF-alpha, and TNF-beta significantly increased MNC formation at very low concentrations: 2.5 x 10(-13) M for IL-1 alpha and IL-1 beta, 10(-11) M for TNF-alpha, and 10(-10) M for TNF-beta In addition, these cytokines enhanced MNC formation in the presence of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], a potent osteotropic factor that stimulates MNC formation by stimulating fusion of mononuclear precursor cells. Simultaneous addition of IL-1 and TNF to the cultures resulted in a synergistic stimulation of MNC formation. These results suggest that: (1) IL-1 and TNF stimulate bone resorption in part by increasing osteoclast formation and (2) an extremely low concentration of these factors can synergistically increase osteoclast formation in the absence of other factors, such as 1,25-(OH)2D3. These data suggest that synergistic interactions among cytokines play an important role in maintaining bone cell activity in normal and pathologic states.     

Interleukin-1 and tumor necrosis factor alpha inhibit repair of the porcine meniscus in vitro

OBJECTIVE: Injury or removal of the knee meniscus leads to progressive joint degeneration, and current surgical therapies for meniscal tears seek to maximally preserve meniscal structure and function. However, the factors that influence intrinsic repair of the meniscus are not well understood. The goal of this study was to investigate the capacity of meniscus tissue to repair a simulated defect in vitro and to examine the effect of pro-inflammatory cytokines on this process. METHODS: Cylindrical explants were harvested from the outer one-third of medial porcine menisci. To simulate a full-thickness defect, a central core was removed and reinserted immediately into the defect. Explants were cultured for 2, 4, or 6 weeks in serum-containing media in the presence or absence of interleukin-1 (IL-1) or tumor necrosis factor alpha (TNF-alpha), and meniscal repair was investigated using mechanical testing and fluorescence confocal microscopy. RESULTS: Meniscal lesions in untreated samples showed a significant capacity for intrinsic repair in vitro, with increasing cell accumulation and repair strength over time in culture. In the presence of IL-1 or TNF-alpha, no repair was observed despite the presence of abundant viable cells. CONCLUSIONS: This study demonstrates that the meniscus exhibits an intrinsic repair response in vitro. However, the presence of pro-inflammatory cytokines completely inhibited repair. These findings suggest that increased levels of pro-inflammatory cytokines post-injury or under arthritic conditions may inhibit meniscal repair. Therefore, inhibition of these cytokines may provide a means of accelerating repair of damaged or injured menisci in vivo.     

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

Summary 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-1α or IL-1β 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 μg/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.     

Soluble tumor necrosis factor receptor prevents post-pump syndrome.

Post-pump syndrome is an acute lung injury following cardiopulmonary bypass (CPB) which is indistinguishable from the adult respiratory distress syndrome (ARDS). Tumor necrosis factor (TNF) is central to the inflammatory process and is capable of triggering the entire pathophysiologic response leading to ARDS. We hypothesized that treatment with a soluble TNF receptor-binding protein (TNFbp) would reduce the increase in serum TNF and prevent acute lung injury in our sequential insult model of ARDS following CPB. Anesthetized pigs were randomized to one of three groups: Control (n = 3), surgical preparation only; CPB + LPS (n = 6), femoral-femoral hypothermic bypass for 1 h followed by infusion of low dose Escherichia coli lipopolysaccharide (LPS; 1 microg/kg); and TNFbp + CPB + LPS (n = 4), pretreatment with intravenous TNFbp (2 mg/kg) followed immediately by both insults. CPB + LPS caused severe lung injury demonstrated by a significant fall in PaO2 and an increase in both intrapulmonary shunt and peak airway pressure as compared to all groups (P < 0.05). These changes were associated with a significant increase in plasma TNF level and pulmonary neutrophil sequestration. TNFbp significantly reduced plasma levels of TNF and prevented the lung injury typically observed with this ARDS model, but did not reduce pulmonary neutrophil sequestration. Thus, elevated serum TNF is not responsible for neutrophil sequestration but does play a role in neutrophil activation which causes lung injury. Prophylactic use of TNFbp in CPB patients may prevent neutrophil activation and reduce the incidence of post-pump ARDS.     

Interleukin-1 receptor antagonist genotype is associated with coronary atherosclerosis in patients with type 2 diabetes

Recently, inflammation has received considerable attention in the pathogenesis of both type 2 diabetes and atherosclerosis. The interleukin-1 receptor antagonist (IL-1ra) is a major modulator of the interleukin-1 pro-inflammatory pathway. We studied the relationship between a variable number tandem repeat (VNTR) polymorphism in intron 2 of the IL-1ra gene (IL1RN) and coronary artery disease (CAD) in patients with and without type 2 diabetes, following 787 consecutive patients admitted for suspected CAD. According to the current criteria of the American Diabetes Association, 250 patients had type 2 diabetes. In this group of patients, allele 2 carriers (n = 108) had an increased prevalence of CAD compared with noncarriers (85.2 vs. 73.2%), a difference that remained significant in a multivariate logistic regression model (odds ratio 2.2, 95% CI 1.1-4.3, P = 0.02). No association of CAD with allele 2 carrier status was present among nondiabetic patients (n = 537). Enzyme-linked immunosorbent assays showed decreased baseline plasma levels of IL-1ra in patients with type 2 diabetes, which may in part explain the role of the IL1RN VNTR in these patients.     

Platelet activating factor receptor antagonist improves survival and attenuates eicosanoid release in severe endotoxemia.

Exogenous platelet activating factor (PAF) causes hypotension, plasma extravasation, metabolic acidosis, and death. These effects are similar to those of endotoxin as well as the eicosanoids. A specific PAF receptor antagonist, BN52021, was used to determine its effects on the hemodynamic events, the eicosanoid production, and on survival in severe rat endotoxemia. Endotoxin alone significantly produced hypotension, prostaglandins (TxB2, PGE2) release, and death. In contrast pretreatment with BN52021, a specific PAF receptor antagonist, significantly altered the hypotension, significantly attenuated the eicosanoid release, and improved the survival rate (p less than 0.01). These findings suggest that PAF receptor activation is an early event in endotoxemia. Eicosanoid release in endotoxemia could be related to PAF synthesis and PAF receptor activation. These findings support the hypothesis that there may be an intimate relationship between PAF and the eicosanoids and that in endotoxemia some of the effects of PAF may be mediated via the cyclo-oxygenase pathway.