Plasma histamine levels during plasmapheresis: difficult interpretation of adverse reactions to plasma substitutes

OBJECTIVES AND DESIGN: The difference in cell proliferation and release of soluble factors in response to interleukin 1beta (IL-1beta) in fibroblasts obtained from patients with osteoarthritis (OA) and rheumatoid arthritis (RA) and from normal skin has been investigated. TREATMENT: The cells were treated with recombinant IL-1beta in the presence or absence of pharmacological agents for 24 h or 48 h. METHODS: Cell proliferation was examined by WST-1 assay, and the amounts of interleukin-6 (IL-6), interleukin-8 (IL-8), macrophage colony stimulating factor (M-CSF), vascular endothelial growth factor (VEGF), matrix metalloproteinase-1 (MMP-1), and prostaglandin E2 (PGE2) were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: IL-1beta dose-dependently enhanced the proliferation of all fibroblasts. The proliferative response to IL-1beta in RA synovial fibroblasts was greater than that in OA synovial and skin fibroblasts. However, there was no difference in spontaneous levels of soluble factors between OA and RA fibroblasts, though medium concentrations of IL-1beta-released VEGF, MMP-1, and PGE2, but not cytokines, in RA were slightly higher than those in OA. Ability to release soluble mediators was pronouncedly increased at 3 h to 9 h after stimulating fibroblasts with IL-1beta for 1 h. The proliferative response to IL-1beta in all fibroblasts was inhibited by dexamethasone and the NF-kappaB inhibitor hymenialdisine but not the cyclooxygenase 2 (COX-2) inhibitor NS-398. But PGE2 prevented proliferation of RA fibroblasts when added to medium up to 3 h after IL-1beta stimulation. Dexamethasone also inhibited the release of IL-6, IL-8, and PGE2 induced by IL-1beta in both OA and RA fibroblasts. NS-398 exhibited an inhibition of IL-1beta-induced IL-6 production as well as PGE2 production. Hymenialdisine inhibited IL-6 production and reduced IL-8 production dependent on synovial cell strains. Methotrexate had no effect on the response to IL-1beta in synovial fibroblasts. CONCLUSION: The present results indicate that the activation of NF-kappaB plays an important role in the proliferative response to IL-1beta in human fibroblasts, and suggest that PGE2 acts as a modulator of cell proliferation in inflamed synovial tissue. It appears that the ability to produce soluble factors in RA synovial fibroblasts is not intrinsic. However, the response to IL-1beta in RA cells seems to be greater than that in OA cells.     

Functional characterization of NF-kappaB inhibitor-like protein 1 (NFkappaBIL1), a candidate susceptibility gene for rheumatoid arthritis

Several studies have implicated the NF-kappaB inhibitor-like protein 1 (NFkBIL1) gene located in the class III region of the major histocompatibility complex (MHC) as a possible susceptibility locus for rheumatoid arthritis (RA). Based on limited homology, it has been suggested to be a member of the inhibitor of NF-kappaB (IkappaB) family of proteins, but a role in mRNA processing has also been proposed. We have investigated the expression of NFkBIL1 in RA synovial tissue and characterized its function. Real-time PCR showed the two NFkBIL1 mRNA splice variants are expressed in a tissue-specific manner. Dual immunofluorescent staining of human RA synovium with polyclonal anti-NFkBIL1 antibodies and anti-CD68, anti-CD3 or anti-factor VIII showed that NFkBIL1 was expressed in the rheumatoid synovial lining and sub-lining layers and co-localized in CD68+ and CD3+, but not Factor VIII+ cells. Confocal microscopy of cultured synovial fibroblasts revealed expression in speckled nuclear and homogenous cytoplasmic distributions, suggesting shuttling between the cytoplasmic and nuclear compartments. Functional tests showed that NFkBIL1 isoforms were incapable of associating with NF-kappaB and did not inhibit it, thus disproving the hypothesis that NFkBIL1 functions as an IkappaB. Affinity purification of endogenous NFkBIL1 proteins and co-immunoprecipitation experiments showed that NFkBIL1 can associate with mRNA and with three protein partners, identified by mass spectrometry as leukophysin, translation elongation factor 1 alpha and CTP synthase I. These data support a potential role for NFkBL1 in the pathogenesis of RA and indicates that it may be involved in mRNA processing or the regulation of translation.     

Regulation of IL-8RA (CXCR1) expression in polymorphonuclear leukocytes by hypoxia/reoxygenation

Interleukin-8 (IL-8) is an important mediator of neutrophil (PMN) function and the type A IL-8 receptor (IL-8RA) mediates these pro-inflammatory signals. Hypoxia or hypoxia/reoxygenation (H/R) affects the production of IL-8, but no data is available regarding its effect on IL-8RA expression. The purpose of this study was to determine the effects of hypoxia and/or H/R on the expression of IL-8RA in PMN. We demonstrated that IL-8RA mRNA levels were similar under normoxic and hypoxic conditions but H/R resulted in a significant reduction in mRNA expression between 30 and 60 min. IL-8RA protein also decreased with reoxygenation of whole blood, which was altered by the addition of specific antioxidants. Therefore, H/R appears to attenuate the effect of IL-8 by down-regulating IL-8RA in PMN. These data show that changes in oxygen tension within the wound site not only affect the expression of inflammatory cytokines, but also control their actions by regulating their receptors.     

反义寡核苷酸抑制缺氧/再给氧时内皮细胞细胞间粘附分子-1的表达

目的:探讨反义寡核苷酸(AS-ODN)对缺氧/再给氧(H/R)时内皮细胞细胞间粘附分子-1(ICAM-1)表达的影响。方法:流式细胞仪测定肾小球血管内皮细胞在缺氧、再给氧及加入AS-ODN后ICAM-1表达的阳性百分率。结果:缺氧10h,肾小球血管内皮细胞ICAM-1的表达与对照组无显著性差异,再给氧6hICAM-1的表达明显高于正常,加入AS-ODN后,ICAM-1阳性细胞的百分率下降40.6%。结论:AS-ODN可以降低H/R时内皮细胞ICAM-1的表达。     

Changes in antioxidant enzymes in isolated cardiac myocytes subjected to hypoxia-reoxygenation.

BACKGROUND: Intracellular antioxidants have been shown to be depressed during hypoxia, and recovery upon reoxygenation has been correlated with the available antioxidant reserve. To test whether these antioxidant changes are also occurring at the cardiac myocytes level, we studied changes in antioxidant enzyme activities as well as cell injury in isolated cardiac myocytes exposed to hypoxia and reoxygenation. EXPERIMENTAL DESIGN: Isolated Ca(2+)-tolerant myocytes from adult male rats were subjected to 30 minutes hypoxia and 15 minutes reoxygenation. Antioxidant enzymes superoxide dismutase, glutathione peroxidase, catalase; lipid peroxide content; electrolytes (Na+, Ca2+); morphology; and high energy phosphates (ATP, ADP, AMP, creatinine phosphate) were studied in these myocytes. The effects of exogenous catalase (40 units/ml) on hypoxia-reoxygenation induced changes in myocytes were also studied. RESULTS: Hypoxia resulted in a reduction in Mn superoxide dismutase and glutathione peroxidase activities with no change in CAT activity and malondialdehyde content. Reoxygenation of hypoxic cells resulted in recovery of Mn superoxide dismutase but not in glutathione peroxidase activity. Reoxygenation was without any effect on catalase activity, but a significant increase in the malondialdehyde content was seen. Hypoxia as well as reoxygenation caused a reduction in the number of rod-shaped cells with a parallel increase in hypercontracted as well as round cells. There was a significant increase in the myocyte Na+ and Ca2+ content during both hypoxia and reoxygenation, and this was accompanied by leakage of lactate dehydrogenase into the perfusion medium. These changes due to hypoxia and reoxygenation were significantly attenuated by addition of catalase (40 units/ml). High energy phosphates ATP, ADP, and AMP declined during hypoxia, and creatine phosphate was significantly reduced during reoxygenation. CONCLUSIONS: Hypoxia induces specific antioxidant changes in the isolated cardiac myocytes. Reduced ability to remove hydrogen peroxide appears to be an important determinant of myocyte injury during reoxygenation.     

Thrombin-induced IL-6 production in human synovial fibroblasts is mediated by PAR1, phospholipase C, protein kinase C alpha, c-Src, NF-kappa B and p300 pathway

Thrombin is a key factor in the stimulation of fibrin deposition, angiogenesis and proinflammatory processes. Abnormalities in these processes are primary features of rheumatoid arthritis (RA) in synovial tissues. We investigated the signaling pathway involved in IL-6 production caused by thrombin in synovial fibroblasts. Thrombin caused concentration- and time-dependent increases in IL-6 production. By using pharmacological inhibitors or activators or genetic inhibition by the protease activated receptor (PAR), siRNA revealed that the PAR1 receptor but not other PAR receptors is involved in thrombin-mediated up-regulation of IL-6. Thrombin-mediated IL-6 production was attenuated by thrombin inhibitor (PPACK), phospholipase C inhibitor (U73122), protein kinase C alpha inhibitor (Ro320432), Src inhibitor (PP2), NF-kappaB inhibitor (PDTC), I kappa B protease inhibitor (TPCK), or NF-kappaB inhibitor peptide. Stimulation of synovial fibroblasts with thrombin activated I kappa B kinase alpha/beta (IKK alpha/beta), I kappa B alpha phosphorylation, I kappa B alpha degradation, p65 phosphorylation at Ser(276), p65 and p50 translocation from the cytosol to the nucleus, and kappaB-luciferase activity. Thrombin-mediated an increase of IKK alpha/beta activity, kappaB-luciferase activity and p65 and p50 binding to the NF-kappaB element was inhibited by PPACK, U73122, Ro320432 and PP2. The binding of p65 and p50 to the NF-kappaB elements, as well as the recruitment of p300 and the enhancement of p50 acetylation on the IL-6 promoter was enhanced by thrombin. Our results suggest that thrombin increased IL-6 production in synovial fibroblasts via the PAR1 receptor/PI-PLC/PKC alpha/c-Src/NF-kappaB and p300 signaling pathway.     

缺氧和高糖对大鼠肾成纤维细胞ICAM-1mRNA表达的影响

目的:探讨缺氧和高糖对肾成纤维细胞(NRK)细胞间粘附分子-1(ICAM-1)mRNA表达的影响。方法:将大鼠NRK分6组进行体外培养:(1)正常浓度葡萄糖组(常糖组):5.6mmol/L葡萄糖;(2)常糖+缺氧组:5.6mmol/L的葡萄糖+100μmol/L的CoCl2;(3)高糖A组:15mmol/L葡萄糖;(4)高糖+缺氧A组:15mmol/L葡萄糖+100μmol/L的CoCl2;(5)高糖B组:30mmol/L葡萄糖;(6)高糖+缺氧B组:30mmol/L葡萄糖+100μmol/L的CoCl2。分别于24h、48h取各组NRK采用RT-PCR检测ICAM-1mRNA表达水平。结果:与常糖组相比,高糖A组,高糖B组ICAM-1mRNA表达量逐渐升高(P<0.01),常糖+缺氧组、高糖+缺氧A、B组ICAM-1mRNA表达量也升高(P<0.01);高糖+缺氧A、B组ICAM-1mRNA表达量分别比高糖A、B组明显升高(P<0.01);高糖A、B组和常糖+缺氧组、高糖+缺氧A、B组48hICAM-1mRNA表达量均高于24h表达量(P<0.01)。结论:高糖和缺氧均可导致ICAM-1mRNA高表达,缺氧可能进一步增加高糖上调ICAM-1的表达。     

红花黄素对大鼠肺动脉内皮细胞P-选择素及ICAM-1表达的影响

目的观察红花黄素在缺氧复氧条件下对大鼠肺动脉内皮细胞P-选择素(Ps)及细胞间黏附分子-1(ICAM-1)基因表达的影响。方法采用细胞培养、RT-PCR、W estern b lot、免疫细胞化学染色法等技术,观察在常氧、缺氧、复氧及红花黄素干预等不同条件下大鼠肺动脉内皮细胞Ps、ICAM-1 mRNA及蛋白表达的变化。结果常氧组细胞1、6、12 h各个时间点,Ps、ICAM-1 mRNA及蛋白表达水平没有明显变化,缺氧组的各个时间点Ps、ICAM-1表达水平与同时间点常氧组相比无统计学差异(P分别>0.05)。缺氧1 h后再给氧1、6、12 h,Ps、ICAM-1 mRNA及蛋白的表达均明显高于相同时间点常氧组与缺氧组(P分别<0.05);缺氧1 h后再给氧同时给予红花黄素干预组Ps、ICAM-1 mRNA及蛋白的表达均明显低于相同时间点单纯缺氧复氧组(P分别<0.05)。结论单纯缺氧状态下大鼠肺动脉血管内皮细胞Ps、ICAM-1表达无明显变化,缺氧复氧条件下Ps、ICAM-1表达上调,红花黄素可抑制缺氧复氧条件下Ps、ICAM-1的过度表达。     

Hypoxia induces expression of the chemokines monocyte chemoattractant protein-1 (MCP-1) and IL-8 in human dermal fibroblasts

Hypoxia is an important factor in the pathophysiology of vascular and inflammatory diseases. Leucocyte infiltration, as a consequence of adhesion molecule up-regulation and chemokine release, is a prominent feature of these diseases. The objective of our study was to investigate the potential role of resident fibroblasts in hypoxia-induced chemotactic responses. We show that MCP-1 and IL-8 mRNA are specifically induced by hypoxia in dermal fibroblasts. This response is paralleled by increased NF-kappaB p65/p50 binding activity, and it is inhibited by pretreatment with N-acetyl-L-cysteine. MCP-1 secreted by fibroblasts is chemotactic for monocytic cells and this activity is significantly increased by hypoxia. Chemotactic index correlates with MCP-1 protein levels and is significantly decreased by neutralizing anti-MCP-1 MoAb. These findings demonstrate the ability of resident fibroblasts to mediate chemotaxis of leucocytes through the release of chemokines in response to hypoxia. Our data point to MCP-1 as an important component in this response, and therefore it may be a potential target in inflammatory responses associated with hypoxia.     

Intercellular adhesion molecule-1 polymorphisms in Korean patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by synovial proliferation and the accumulation of inflammatory cells in the affected joints. Intercellular adhesion molecule-1 (ICAM-1) is readily detected in RA synovial tissues and helps recruit inflammatory cells to the joint. ICAM-1 shows genetic polymorphisms at codons 241 (R241G) and 469 (K469E). In order to investigate the association between ICAM-1 gene polymorphisms and RA, we genotyped ICAM-1 R241G and ICAM-1 K469E polymorphisms in 143 Korean patients with RA, and in 138 healthy controls, by using the polymerase chain reaction-restriction fragment length polymorphism method. No polymorphism of R241G was found in Korean subjects. However, the frequency of the K469 allele was found to be significantly lower in RA patients than in healthy controls. Allele frequency of K469 was lower in RA patient group, compared to that in healthy controls, regardless of the shared epitope status. Distribution of K469E allele frequencies was not different whether the patient had rheumatoid factor, radiographic erosion or extra-articular complications. In conclusion, this study shows lower frequency of the ICAM-1 K469E allele in Korean patients with RA than that in healthy controls.     

Hypoxia induces production of citrullinated proteins in human fibroblast‐like synoviocytes through regulating HIF1α

Hypoxia is a prominent microenvironment feature in a range of disorders including cancer, rheumatoid arthritis (RA ), atherosclerosis, inflammatory bowel disease (IBD ), infection and obesity. Hypoxia promotes biological functions of fibroblast‐like synoviocytes via regulating hypoxia‐inducible factor 1α (HIF 1α). Dysregulated protein citrullination in RA drives the production of antibodies to citrullinated proteins, a highly specific biomarker of RA . However, the mechanisms promoting citrullination in RA are not yet fully elucidated. In this study, we investigated whether pathophysiological hypoxia as found in the rheumatoid synovium modulates the citrullination in human fibroblast‐like synoviocytes (HFLS ). Here, we found that peptidylarginine deiminase 2 (PAD 2) and citrullinated proteins were increased in HFLS after exposure to hypoxia. Moreover, knocking down HIF 1α by HIF 1α siRNA ameliorated the expression of PAD 2 and citrullinated proteins. Collectively, this study provides a new mechanism involved in generating citrullinated proteins: hypoxia promotes citrullination and PAD production in HFLS . Concurrently, we also proposed a novel hypoxia involved mechanism in RA pathogenesis. This study deepens our understanding of the role of hypoxia in the pathogenesis of RA and provides a potential therapeutic strategy for RA .     

Expression of interleukin-1 and interleukin-1 receptor antagonist by human rheumatoid synovial tissue macrophages.

Interleukin-1 (IL-1) has protean effects in the pathogenesis of rheumatoid arthritis (RA). These effects include production of prostaglandins and collagenase from rheumatoid fibroblasts as well as upregulation of adhesion molecule expression on these cells. IL-1 can activate monocytes and neutrophils, as well as promote the growth of fibroblasts and endothelial cells. Recently, a novel interleukin-1 receptor antagonist protein (IRAP) has been isolated, purified, cloned, and expressed, which may modulate the effects of IL-1. In this study, we present data demonstrating that macrophages isolated from human RA synovial tissues express both IL-1 and IRAP genes. In addition, RA synovial tissue macrophages and lining cells display IL-1 and IRAP antigenic expression by immunohistochemistry. In contrast, osteoarthritis synovial tissues, as compared to RA, have fewer IL-1 and IRAP-positive macrophages. Thus, the production of IL-1 balanced by IRAP may affect the joint destruction found in these diseases.     

Clock gene expression in different synovial cells of patients with rheumatoid arthritis and osteoarthritis

Patients with rheumatoid arthritis (RA) show modulated circadian rhythms of inflammatory cytokines and cortisol, which may be associated with a modified expression of clock genes. The expression of major clock genes was previously studied in synovial tissues and fibroblasts of patients with RA and osteoarthritis (OA). We therefore especially aimed to examine the localization of clock genes at the cellular level in synovial tissue. Furthermore we were interested in studying the expression of the D site of albumin promoter (albumin D-box) binding protein (DBP) at the immunohistochemical level in human samples. Methods used include the in situ expression of the clock genes Brain and muscle aryl hydrocarbon receptor nuclear translocator-like 1 (Bmal 1), Circadian Locomotor Output Cycles Kaput (Clock), Period 1 and 2 (Per 1 and Per 2), and DBP was examined by immunohistochemistry in synovial tissues of patients with RA or OA. Additionally, expression profiles of different clock genes were determined over 24 h by real time PCR in synovial fibroblasts (SFs) after a 2 h serum shock or TNF-α. Results show that all clock genes investigated were found to be expressed both in RA and OA synovial tissues. Double staining against cell specific markers revealed that clock proteins were especially seen in macrophages, SFs and B-lymphocytes. Cell counting showed that clock proteins were found in approximately 5–20% of cells. Additionally, preliminary cell culture experiments showed that TNF-α treatment resulted in differential 24 h expression profiles between RA and OA samples and also compared to the results obtained from the serum shock experiments. From our study we conclude that the major clock genes, including DBP, are expressed in samples from RA and OA patients, especially in macrophages and synovial fibroblasts, but also in B-lymphocytes. Preliminary experiments suggest that TNF-α seems to be able to modify clock gene expression in synovial fibroblasts.     

The effect of sulfasalazine on rheumatoid arthritic synovial tissue chemokine production

Rheumatoid arthritis (RA) is an aggressive inflammatory disease in which chemokines are thought to recruit leukocytes and induce angiogenesis. The aim of this study was to investigate the effects of sulfasalazine (SASP) and its metabolites, sulfapyridine (SP), and 5-aminosalicylic acid (5ASA) on chemokine production by RA synovial tissue explants and interleukin (IL)-1beta-stimulated RA synovial tissue fibroblasts using enzyme-linked immunosorbent assays and flow cytometry. Synovial tissue explants from RA patients secreted a decreased amount of the chemokines IL-8 and growth-related gene product alpha (GROalpha) when treated with SASP over a broad range of concentrations based on the typical clinical dosage of 2 g/day. SP had a significant effect in that it decreased RA synovial tissue explant secretion of IL-8 (22%), GROalpha (55%), and monocyte chemotactic protein-1 (MCP-1) (42%) (P < 0.05). 5ASA had no effect on RA synovial tissue explant production of IL-8 and MCP-1, while increasing GROalpha production. In IL-1beta-stimulated RA synovial tissue fibroblasts, SASP significantly increased chemokine secretion, while SP significantly decreased IL-8 (24%) and GROalpha (21%) secretion (P < 0.05). Flow cytometry showed that the number of IL-8 expressing RA synovial tissue fibroblasts did not significantly change following SP treatment. These data suggest that SASP may function to reduce inflammation in RA through the effects of its metabolite SP to reduce the secretion of the inflammatory chemokines IL-8, GROalpha, and MCP-1.     

Pirfenidone induces intercellular adhesion molecule-1 (ICAM-1) down-regulation on cultured human synovial fibroblasts

Pirfenidone has been shown to modify some cytokine regulatory actions and inhibit fibroblast biochemical reactions resulting in inhibition of proliferation and collagen matrix synthesis by fibroblast. We have investigated the effect of pirfenidone on the expression of cell adhesion molecules. The synovial fibroblasts were treated with IL-1α in the presence or absence of pirfenidone (range 0–1000 μM ), and assayed for the expression of adhesion molecules such as ICAM-1 and endothelial-leucocyte adhesion molecule-1 (E-selectin) by cell ELISA. Pirfenidone significantly down-regulated the expression of ICAM-1 on cultured synovial fibroblasts in a dose-dependent manner. In contrast, expression of E-selectin was not affected. Furthermore, we examined whether pirfenidone affects the cellular binding between cultured lymphocytes and IL-1α-stimulated synovial fibroblasts by in vitro binding assay and found their mutual binding was significantly suppressed in a dose-dependent manner by pirfenidone. It is speculated that down-regulation of ICAM-1 might be one of the novel mechanisms of action of pirfenidone. These data indicate a novel mechanism of action for pirfenidone to reduce the activation of synovial fibroblasts.     

siRNA 技术沉默SOCS3 对缺氧复氧心肌细胞增殖、凋亡的影响以及作用机制

目的：研究小干扰RNA（siRNA）靶向沉默细胞因子信号转导抑制因子3（SOCS3）基因对心肌细胞增殖、凋亡的影响以及可能作用机制。方法：采用脂质体Lipofectamine 2000转染大鼠H9C2心肌细胞,分为对照组、缺氧/复氧组、缺氧/复氧+siRNA NC组、缺氧/复氧+siRNA SOCS3组;免疫印迹试验（Western blot）检测细胞的转染效果;噻唑蓝（MTT）观察细胞的增殖活性,观察细胞中乳酸脱氢酶（LDH）、超氧化物歧化酶（SOD）、丙二醛（MDA）水平的变化;膜联蛋白 V-FITC（Annexin V-FITC）/碘化丙啶(PI)染色法检测细胞凋亡率,Western blot检测核因子-κB（NF-κB）、细胞周期蛋白D1（Cyclin D1）、c-Myc蛋白水平。结果：与对照组相比,缺氧/复氧组心肌细胞SOCS3蛋白水平显著增加（P<0.05）,细胞的增殖活性、SOD显著下降（P<0.05）,LDH、MDA、凋亡率显著升高（P<0.05）;靶向沉默缺氧复氧心肌细胞SOCS3基因表达较缺氧/复氧组细胞的增殖活性和SOD显著增加（P<0.05）,LDH、MDA、凋亡率显著降低（P<0.05）;缺氧/复氧干预心肌细胞显著抑制NF-κB、Cyclin D1、c-Myc蛋白表达（P<0.05）,下调SOCS3基因表达显著增加NF-κB、Cyclin D1、c-Myc蛋白表达（P<0.05）。结论：沉默SOCS3表达促进缺氧复氧心肌细胞增殖,抑制其凋亡,增强机体氧自由基的清除能力,其作用机制与NF-κB信号通路的激活有关。