Comparison of the immunomodulatory effects of the plant sterol β-sitosterol to simvastatin in peripheral blood cells from multiple sclerosis patients

Statins as hypocholesterolimic drugs have recently shown to have ant-inflammatory properties and thus are being assessed for the treatment of multiple sclerosis (MS). Dietary phytosterols such as β-sitosterol (SIT) are also hypocholesterolemic compounds and from preliminary studies they appear to have also anti-inflammatory properties. In this communication, we report on studies to investigate the immunomodulatory effects of SIT on proliferation and release of key cytokines from peripheral blood mononuclear cells (PBMC) of MS patients. In PBMC of MS patients, 16 μM SIT had no effect on cell proliferation; however simvastatin (SV) at 10 and 20 μM reduced cell proliferation by as much as 60%. SIT (4 μM) reduced TNF-α release by 24% in PBMC of MS patients whereas 10 μM SV reduced TNF-α release by 94%. SIT reduced IL-12 release in MS patients at 4 and 16 μM by 27% and 30%, respectively. In healthy subjects, 16 μM SIT increased the anti-inflammatory cytokine IL-10 by 47% whereas 10 μM SV decreased IL-10 by 30%. In PBMC of MS patients, SIT had no effect on IL-10 release whereas 10 μM SV reduced IL-10 by 62%. SIT (4 μM) reduced IL-5 release by 47% in MS patients while 10 μM SV reduced IL-5 by 89%. The results show that SIT is effective in modulating the secretion of pro/anti-inflammatory cytokines and suggest a potential beneficial effect of SIT in MS management without the side effects associated with statin therapy.     

Stimulation of cytokine production in human peripheral blood mononuclear cells by an aqueous Chlorella extract

CPE is an aqueous extract of the edible micro alga Chlorella pyrenoidosa, which has been shown to have immunostimulatory effects in vivo. In the present study, CPE was evaluated for an ability to stimulate cytokine production by human peripheral blood mononuclear cells (PBMC). PBMC from healthy individuals were treated ex vivo for 24 hours with 1, 10 and 100 microg/mL CPE. This resulted in a marked increase in the level of IL-10, a regulatory cytokine, and strong stimulation of the T-helper-1 (Th1) cell cytokines, IFN-gamma and TNF-alpha. In contrast, stimulation of representative T-helper-2 (Th2) cell cytokines, IL-4 and IL-13, was minor. CPE (1, 10 or 100 microg/mL) did not cause a proliferation of human PBMC suggesting that enhanced secretion of cytokines was not secondary to an increase in cell number. We conclude that CPE stimulation of human PBMC induces a Th1-patterned cytokine response and a strong anti-inflammatory regulatory cytokine response, observations that await confirmation in vivo.     

Immune responses to novel allergens and modulation of inflammation by vitamin K3 analogue: a ROS dependent mechanism

The possibility of newer allergens being responsible for atopy needs to be explored at regional level due to environmental variables. Current studies were undertaken to identify common environmental allergens causing atopy in a defined population of India and to correlate the presence of various risk factors with the clinical presentation of allergy. Newer allergens like human dander and rice grain dust were identified and reported as the most common cause of atopy in this region. Atopy, elevated serum total IgE and familial tendency, was observed in 88%, 69% and 58% of allergic patients respectively. Further, allergen-specific immune responses like lymphocyte proliferation and cytokine secretion were studied in vitro using peripheral blood mononuclear cells (PBMC) isolated from both allergic and non-allergic individuals. Although, some allergens induced significant lymphocyte proliferation in vitro, allergen-induced cytokine secretion except that of TNF-α was not seen. Significantly higher ratio of secreted IL-4/IFN-γ cytokines was observed in PBMC isolated from allergic subjects in response to PHA. Plumbagin (vitamin K3 analogue) completely inhibited PHA-induced cytokine production in PBMC, in both allergic and non-allergic individuals. Plumbagin modulated the levels of intracellular reactive oxygen species and glutathione and suppressed PHA induced activation of NF-κB in human PBMC. The results thus show in human PMBC, for the first time, the anti-allergic and anti-inflammatory effects of plumbagin and underscore its therapeutic potential.     

他汀类药物对C反应蛋白直接诱导人外周血单个核细胞IL-6表达的影响

目的　观察离体急性冠状动脉综合征 (ACS)病人外周血单个核细胞对C 反应蛋白 (CRP)直接刺激的反应性及亲水性他汀 (普伐他汀 )与亲脂性他汀 (氟伐他汀 ,辛伐他汀 )药物干预后的效果。方法　离体培养ACS(n =15 )病人、稳定型心绞痛 (SAP)病人 (n =13)与健康人 (n =15 )外周血单个核细胞 ,CRP(2 0mg·L-1)刺激细胞 2 4h后检测细胞培养液上清中IL 6的表达 (ELISA)。普伐他汀、氟伐他汀、辛伐他汀分别按照不同浓度 (1× 10 -6,2 5× 10 -6,5× 10 -6,7 5× 10 -6,1× 10 -5mol·L-1)预先孵育细胞 2h后继以CRP刺激 2 4h ,ELISA分析培养液上清中的IL 6水平。结果　CRP(2 0mg·L-1)明显激活ACS病人外周血单个核细胞IL 6的表达。健康组、SAP组和与ACS组IL 6表达分别为(987± 10 2 )ng·L-1,(991± 134)ng·L-1,(312 9± 333)ng·L-1,均较其基础状态 (未受CRP刺激 )明显增高 (P <0 0 5 ) ;受CRP刺激状态下 ,ACS组IL 6表达是健康组的数倍(P <0 0 5 )。ACS病人外周血单个核细胞在不同剂量普伐他汀、氟伐他汀、辛伐他汀药物干预下 ,IL 6表达下降水平有所不同。结论　一定浓度的CRP能直接诱导人外周血单个核细胞IL 6表达增加 ,提示CRP能直接激活炎症反应 ,在ACS及其并发症的病理机制中可能发挥重要作用。他汀类药?     

Simvastatin stimulates macrophage interleukin-1beta secretion through an isoprenylation-dependent mechanism

Statin treatment inhibits oxidized lipoprotein-induced intracellular lipid accumulation (foam cell formation) and reduces plasma levels of inflammatory markers such as interleukin-1beta (IL-1beta). The aim of the present study was to determine if simvastatin affected lipid accumulation in macrophages incubated with aggregated low density lipoproteins (AgLDL) and whether simvastatin had a direct effect on cytokine secretion from macrophages. Simvastatin treatment did not inhibit AgLDL-induced macrophage lipid accumulation, but significantly increased the secretion of IL-1beta and IL-8 from macrophages, whilst inhibiting the secretion of tumor necrosis factor-alpha (TNF-alpha) and having no significant effect on IL-6 secretion. Increased macrophage lipid content did not block statin-induced IL-1beta and IL-8 secretion. Simvastatin-stimulated IL-1beta secretion from macrophages was inhibited by isoprenoids. We therefore hypothesized that simvastatin stimulated IL-1beta secretion by affecting isoprenylation-dependent signaling pathways. Another possible mechanism for affecting such signaling is to impair isoprenoid transfer protein activity with specific inhibitors such as GGTI-297 and FTInhI. This treatment resulted in strong stimulation of IL-1beta secretion that was further enhanced when exogenous IL-1beta was present at the beginning of treatment. These data suggest an isoprenylation-dependent negative-feedback loop for macrophage IL-1beta secretion that is inhibited by statin treatment.     

Effects of C-reactive Protein and Homocysteine on Cytokine Production: Modulation by Pravastatin

Objective.  C-reactive protein (CRP) and homocysteine are markers of cardiovascular risk that may have inflammatory effects. HMG coenzyme A reductase inhibitors (statins) have anti-inflammatory effects in vitro, but it is not clear if such responses in vivo are secondary to lipid lowering. We examined the hypothesis that CRP and homocysteine would stimulate cytokine release in human whole blood and that short-term treatment with a statin would inhibit it.
Methods.  The time course of IL-6 and MCP-1 production was determined in whole blood incubated with saline, 1 µg/mL lipopolysaccaride (LPS), 50 and 100 µM/L DL-homocysteine, and 5 µg/mL human recombinant CRP for 24 hours at 37°C under 5% CO₂ atmosphere. Cytokine responses were determined in blood drawn from 15 healthy volunteers before and after administration of pravastatin 40 mg daily for 2 days.
Results.  Both human recombinant CRP and LPS significantly increased the production of IL-6 and MCP-1 in whole blood samples more than 4-fold ( P  < 0.001) but homocysteine did not. Oral administration of pravastatin, 40mg daily for 2 days, decreased CRP-stimulated IL-6 production by approximately 20% ( P  = 0.02) 6 hours after incubation, but did not affect MCP-1 production ( P  = 0.69). Pravastatin treatment did not affect LPS-stimulated MCP-1 but increased IL-6 modestly.
Conclusions.  CRP stimulated the production of the proatherogenic mediators MCP-1 and IL-6 in human whole blood, but homocysteine did not. CRP-stimulated production of IL-6, but not MCP-1, was modestly attenuated by short-term treatment with pravastatin.     

Statin induced myotoxicity: The lactone forms are more potent than the acid forms in human skeletal muscle cells in vitro

Statins exist in both acid and lactone forms in vivo. High plasma levels of the lactone forms have been observed in patients with statin induced myopathy. In the present study, the hypothesis that lactone forms have a higher potency of inducing myotoxicity as compared to acid forms was investigated. Primary human skeletal muscle cells were incubated with increasing concentrations of lactone and acid forms of atorvastatin, fluvastatin, pravastatin and simvastatin. Following incubation, living myotubes were quantified by fluorescence staining. Atorvastatin lactone showed a 14-fold, fluvastatin lactone a 26-fold, pravastatin lactone a 23-fold, and simvastatin lactone a 37-fold higher potency to induce myotoxicity compared to their corresponding acid forms. Thus, for the four different statins the present study shows a significantly higher potency of the lactone forms, than the respective acid forms, to induce myotoxicity in human skeletal muscle cells in vitro. These results clearly indicate the need to differentiate between acid and lactone forms in future investigation of statin myotoxicity.     

The mycotoxins citrinin,gliotoxin, and patulin affect interferon-gamma rather than interleukin-4 production in human blood cells

Exposure to molds diminishes the numbers of T-helper type 1 (Th1) cells in the peripheral blood of children and is a risk factor for the development of allergic diseases (results of LARS: Leipzig Allergy Risk Children Study, Mueller et al. 2002). We hypothesized that mycotoxins are responsible for this effect and therefore investigated the influence of citrinin, gliotoxin, and patulin on human peripheral blood mononuclear cells (PBMC). CD3/CD28-stimulated PBMC of healthy donors were incubated for 24 h with the mycotoxins in serial dilutions and triplicates. Vitality and proliferation were tested using the MTT assay and T-cell function by the expression of cytokines (ELISA, intracellular cytokine staining, and real-time polymerase chain reaction (RT-PCR) for interferon-gamma (IFN-gamma) and interleukin-4 (IL-4). The cytokine secretion was inhibited at concentrations 2-130 times lower compared to vitality (ELISA versus MTT assay). The strongest inhibition of cytokine expression was found for IFN-gamma: 8.3 microg/mL citrinin, 34.2 ng/mL gliotoxin, and 64.8 ng/mL patulin caused a 50% inhibition of the IFN-gamma release (50% inhibitory dose, ID(50)). For IL-4 release the corresponding ID(50) values were 21.6 microg/mL citrinin, 82.8 ng/mL gliotoxin, and 243.2 ng/mL patulin. Furthermore, 3 ng/mL patulin caused a significant increase of IL-4 but a significant suppression of IFN-gamma. On the mRNA level, after 24 h an unaltered or enhanced IL-4 was observed compared to a reduced IFN-gamma expression. Using a method of intracellular cytokine staining, we were able to show that the described effects are caused by a reduction of the number of IFN-gamma-producing T lymphocytes rather than by a reduced functional capacity of the single cell. We suggest that mycotoxins primarily cause stronger inhibition of IFN-gamma-producing Th1 cells, which may lead to T-cell polarization toward the Th2 phenotype and may raise the risk for the development of allergies.     

HMG CoA reductase inhibitors affect the fibrinolytic system of human vascular cells in vitro: a comparative study using different statins

1. The results of several clinical studies investigating the effect of statin therapy on the fibrinolytic system in vivo are inconclusive. We compared the effect of six different statins (atorvastatin, cerivastatin, fluvastatin, lovastatin, pravastatin, simvastatin) on components of the fibrinolytic system expressed by human vascular endothelial cells and smooth muscle cells and by the human hepatoma cell line HepG2. 2. All statins used except pravastatin significantly decreased PAI-1 production in human endothelial and smooth muscle cells. This effect was also seen in the presence of IL-1 alpha and TNF-alpha. All statins except pravastatin increased t-PA production in human smooth muscle cells. On a molar basis cerivastatin was the most effective HMG CoA reductase inhibitor used. Only simvastatin and lovastatin increased t-PA production in endothelial cells. The effects on the fibrinolytic system were reversed by mevalonate. Statins decreased mRNA levels for PAI-1 in endothelial and smooth muscle cells and increased mRNA levels for t-PA in smooth muscle cells. Statins did not affect PAI-1 expression in HepG2 cells. Cell viability was not influenced by statins in endothelial cells and HepG2 cells whereas in smooth muscle cells a cytotoxic effect was seen at high concentrations. 3. If the effects on the fibrinolytic system of vascular cells in vitro shown in this study are also operative in vivo one could speculate that by increasing t-PA and decreasing PAI-1 at sites of vascular lesions statins might reduce fibrin formation and thrombus development. Such an effect might contribute to the clinically proven benefits of statin therapy.     

Patulin influences the expression of Th1/Th2 cytokines by activated peripheral blood mononuclear cells and T cells through depletion of intracellular glutathione

Patulin is a mold toxin secreted mainly by fungi of the Penicillium species. Exposure generally results from consumption of moldy fruits and fruit products. Since recent studies identified mold exposure as a risk factor for allergic diseases, we examined the effects of patulin on human peripheral blood mononuclear cells (PBMC) prepared from buffy coats of healthy donors. Cells were stimulated with CD3- and CD28-specific antibodies in the presence or absence of patulin. Effects of patulin on PBMCs were evaluated by proliferation, viability assays, and cytokine ELISAs. The presence of 50 ng/mL patulin strongly decreased the amounts of several cytokines in the supernatant of stimulated PBMCs. This decrease in cytokine secretion was not due to cytotoxic effects of patulin. Moreover, the extent of the reduction of cytokine amounts was cytokine specific, affecting some (IL-4, IL-13, IFNgamma, and IL-10), but not others (IL-8, IL-5). We show that all effects could be abolished by adding thiol containing compounds. A depletion of intracellular GSH could be measured after incubation of cells with patulin. Taken together, our data indicate that patulin modulates the functional activation of PBMCs with respect to proliferation and cytokine secretion patterns by depletion of intracellular GSH. The depletion of intracellular glutathione may influence the balance between Th1 and Th2 cells and have implications for allergic diseases.     

Cannabinoids Decrease the Th17 Inflammatory Autoimmune Phenotype

Cannabinoids, the Cannabis constituents, are known to possess anti-inflammatory properties but the mechanisms involved are not understood. Here we show that the main psychoactive cannabinoid, Δ-9-tetrahydrocannabinol (THC), and the main nonpsychoactive cannabinoid, cannabidiol (CBD), markedly reduce the Th17 phenotype which is known to be increased in inflammatory autoimmune pathologies such as Multiple Sclerosis. We found that reactivation by MOG35-55 of MOG35-55-specific encephalitogenic T cells (cells that induce Experimental Autoimmune Encephalitis when injected to mice) in the presence of spleen derived antigen presenting cells led to a large increase in IL-17 production and secretion. In addition, we found that the cannabinoids CBD and THC dose-dependently (at 0.1–5 μM) suppressed the production and secretion of this cytokine. Moreover, the mRNA and protein of IL-6, a key factor in Th17 induction, were also decreased. Pretreatment with CBD also resulted in increased levels of the anti-inflammatory cytokine IL-10. Interestingly, CBD and THC did not affect the levels of TNFα and IFNγ. The downregulation of IL-17 secretion by these cannabinoids does not seem to involve the CB1, CB2, PPARγ, 5-HT_1A or TRPV1 receptors. In conclusion, the results show a unique cannabinoid modulation of the autoimmune cytokine milieu combining suppression of the pathogenic IL-17 and IL-6 cytokines along with boosting the expression of the anti-inflammatory cytokine IL-10.     

3种他汀类药物抗炎作用的实验研究

目的:研究3种他汀类药物的抗炎作用.方法:急性抗炎模型采用巴豆油致小鼠耳肿胀模型和角叉菜胶致大鼠足肿胀模型,慢性抗炎模型采用棉球植入小鼠腹腔致肉芽肿模型.以布洛芬作为阳性对照,观察洛伐他汀、辛伐他汀和普伐他汀的抗炎作用.结果:他汀类药物对巴豆油致小鼠耳肿胀、角叉菜胶致大鼠足肿胀和棉球致小鼠腹腔肉芽肿形成均有显著的抑制作用.结论:他汀类药物具有显著的抗炎作用.     

Histone deacetylase inhibitor suberoylanilide hydroxamic acid exhibits anti-inflammatory activities through induction of mitochondrial damage and apoptosis in activated lymphocytes

Suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, has been proven to be an anti-cancer agent. Its anti-inflammatory activities have recently been observed both in in vitro and in vivo models. Yet its action on lymphocytes and the underlying mechanism are still not well known. In this study, in order to evaluate the anti-inflammatory function of SAHA, we analyzed the effects of SAHA on the proliferation, activation, cytokines secretion, cell cycle distribution and apoptosis of murine lymphocytes activated with concanavalin A (Con A). Our results demonstrated that SAHA inhibited the proliferation of Con A-activated lymphocytes in a dose-dependent manner. The expression of CD69 on CD3(+) T lymphocytes was significantly inhibited by SAHA. Intracellular cytokine staining analysis showed that SAHA could downregulate the expression of pro-inflammatory cytokines TNF-α, IL-6 and IFN-γ in T lymphocytes. Furthermore, analysis of sub-G(0)/G(1) peaks and annexin V binding populations revealed that SAHA induced apoptotic cell death in Con A-activated lymphocytes. Consistent with these results, SAHA treatment also induced a decrease of mitochondrial membrane potential and cleavage of caspase-3 and PARP in these cells. Moreover, SAHA caused an accumulation of phosphorylated histone H2A.X, indicating increased double strand DNA breaks. These findings suggest that induction of apoptosis through the mitochondrial pathway may contribute to the anti-inflammatory activities of SAHA on activated lymphocytes.     

Dimethoxycurcumin, a metabolically stable analogue of curcumin, exhibits anti-inflammatory activities in murine and human lymphocytes

The aim of this study was to investigate whether dimethoxycurcumin (DiMC), a synthetic curcumin analogue having higher metabolic stability over curcumin, could exhibit anti-inflammatory activity in murine and human lymphocytes. Both curcumin and DiMC suppressed mitogen as well as antigen driven proliferation of murine splenic lymphocytes. Further, mitogen and antigen-stimulated cytokine (IL-2, IL-4, IL-6 and IFN-γ) secretion by T cells was also abrogated by curcumin and DiMC. Interestingly, curcumin and DiMC suppressed B cell proliferation induced by lipopolysaccharide. Curcumin and DiMC also inhibited Con A-induced activation of early and late T cell activation markers. They scavenged basal reactive oxygen species and depleted GSH levels in lymphocytes. The suppression of mitogen-induced T cell proliferation and cytokine secretion by curcumin and DiMC was significantly abrogated by thiol containing antioxidants suggesting a role for redox in their anti-inflammatory activity. Further, the possibility of curcumin and DiMC directly interacting with thiol-containing antioxidant GSH was monitored by changes in absorbance. Both curcumin and DiMC inhibited Con A induced activation of NF-κB and MAPK. More importantly, curcumin and DiMC inhibited phytohaemagglutinin induced proliferation and cytokine secretion by human peripheral blood mononuclear cells. To explore their therapeutic efficacy, they were added to lymphocytes post-Con A stimulation and we observed a significant suppression of IL-2, IL-6 and IFN-γ. The present study for the first time demonstrates the potent anti-inflammatory activity of DiMC. Further, DiMC could find application as an alternative to curcumin, which is currently used in several clinical studies, due to its superior bioavailability and comparable efficacy.     

Inhibition of in vitro tumor cell proliferation by cytokines induced by combinations of TLR or TLR and TCR agonists

The objective of this study was to learn from in vitro studies how to better utilize Toll-like receptor (TLR) agonists in controlling tumor growth. One of the primary effects of TLR agonists is induction of cytokine and chemokine production. In order to identify combinations of cytokines or chemokines with optimal ability to inhibit in vitro tumor cell proliferation, a panel of 17 recombinant human or mouse cytokines that have minimal effect on primary cell survival, were tested individually or in combinations of 2, 3 or 4 on a panel of human and mouse chemotherapy sensitive and resistant tumor cell lines. A combination of high (>10 ng/ml) levels of IFNgamma with moderate concentrations of TNFalpha>IFNalpha>IL-6=IL-8 was most effective at inhibiting in vitro tumor cell viability and proliferation with minimal effect on primary cells. We also observed that similar cytokine profile could be induced in vitro PBMC culture by using certain combinations of TLR-TLR and TLR-TCR agonists. Thus, concomitant activation of TLR7/8 with TLR4 or TLR 7/8 with T cell receptor (TCR) in PBMC, amongst all possible paired TLR-TLR and TLR-TCR agonist combinations, produced cytokine mix high in IFNgamma, in combination with IFNalpha, IL-6, IL-8, TNFalpha. Such cytokine mix was equal or more effective tumor cell killing and inhibition of tumor cell proliferation than the best rec-cytokine mixture tested. These results suggest that, TLR and/or TCR agonists combinations generate an optimal mixture of cytokines and chemokines competent in regulating in vitro tumor growth, and imply that realizing such "right cytokine induction" in vivo might be more efficacious than that with individual cytokines or TLR agonists induced cytokine mix.     

Effect of cytokines and anti-arthritic drugs on glycosaminoglycan synthesis by bovine articular chondrocytes

The effect of cytokines (interleukin-1 alpha, interleukin-1 beta, and tumor necrosis factor alpha) and several anti-arthritic drugs on glycosaminoglycan synthesis and secretion into medium by bovine articular chondrocytes was examined. Sulfated glycosaminoglycans (S-GAG) were measured by a modified 1,9-dimethylmethylene blue (DMB) dye binding assay. Hyaluronate (HA) was measured by an inhibition ELISA based on specific binding to a proteoglycan. All three cytokines caused a dose-dependent decrease in S-GAG production and a dose-dependent increase in HA production. Non-steroidal anti-inflammatory drugs (NSAIDs, indomethacin, naproxen, and piroxicam, 1 microM) could not reverse the effect of IL-1 alpha on inhibiting S-GAG and stimulating HA synthesis. The anti-inflammatory steroid (dexamethasone, 1 microM) depressed HA synthesis by 50-70% in the absence or presence of IL-1 alpha. Dexamethasone depressed S-GAG synthesis by 20-30% in the absence or presence of IL-1 alpha. Therefore, none of the tested anti-rheumatic drugs reversed the cytokine mediated changes in glycosaminoglycan synthesis by bovine chondrocytes.     

碱性成纤维细胞生长因子增强淋巴因子激活的杀伤细胞对人膀胱 …

目的 探讨白细胞介素Ⅱ（ＩＬ－２）和碱性成纤维细胞生长因子（ｂＦＧＦ）对膀胱癌患者淋巴因子激活的杀伤细胞（ＬＡＫ细胞）的作用。方法 用细胞计数观察不同浓度ｂＦＧＦ对ＬＡＫ细胞增殖的影响,以膀胱癌细胞系ＥＪ及新鲜分离患者自体肿瘤细胞（ＢＴＣ）为靶细胞,用ＭＴＴ法测定ＬＡＫ细胞对膀胱癌细胞的细胞毒作用,结果 虽然外周血单核细胞（ＰＢＭＣ）的增殖可被ｂＦＧＦ５μｇ．Ｌ＾－１所抑制,ＩＬ－２所诱导的ＬＡＫ