过氧化物酶体增生物激活受体-γ在小鼠噁唑酮结肠炎中作用的研究

背景：溃疡性结肠炎（UC）的肠道病变不仅与上皮炎症和坏死有关，也与上皮细胞过度凋亡有关．目前观点认为促炎和抗炎细胞因子失衡在UC发病中起关键作用。过氧化物酶体增生物激活受体（PPAR）-γ可能参与了UC肠道炎症的调控。目的：观察小鼠噁唑酮结肠炎的疾病活动度、PPAR-γ的表达以及PPAR-γ与促炎因子和凋亡相关因子的关系，并以PPAR-γ配体吡格列酮进行干预，探讨PPAR-γ在实验性结肠炎中的作用。方法：将噁唑酮结肠炎小鼠随机分为模型组和吡格列酮治疗组，每日观察、记录各组小鼠的体重和大便情况，计算疾病活动指数（DAI）。分别于实验第10、11、12、13d处死小鼠，观察结肠大体和组织学改变并计分，以免疫组化方法检测PPAR-γ、核因子（NF）-κB p65、Fas及其配体FasL和caspase-3的表达。结果：治疗组DAI和大体、组织学损伤计分的改善较模型组显著（P〈0．05）；与同时间点模型组相比，治疗组PPAR-γ表达阳性率显著增高，NF-κB p65、Fas、FasL和caspase-3表达阳性率显著降低（P〈0．05）。结论：PPAR-γ可抑制NF-κB活化和结肠上皮细胞凋亡。其配体吡格列酮可促进PPAR-γ的表达，从而缓解结肠炎症，并可能具有抑制结肠上皮细胞过度凋亡的功能。     

罗格列酮对日本血吸虫病肝纤维化小鼠肝组织核因子-κB和过氧化物酶体增殖物激活受体γ表达的影响

目的观察日本血吸虫病肝纤维化小鼠肝脏肝组织核因子-κB(NF-κB)的活性和过氧化物酶体增殖物激活受体γ(PPARγ)的表达,及PPARγ配体罗格列酮对其表达的影响.方法50只昆明小鼠,随机分为正常对照组、感染对照组、吡喹酮治疗组、罗格列酮治疗组及罗格列酮加吡喹酮治疗组.除正常对照组外,其余各组均建立血吸虫病肝纤维化小鼠模型.用HE染色观察肝组织光镜下的病理改变.用Western blot方法,实时荧光定量PCR反应观察小鼠肝组织NF-κB的活性变化与PPARγmRNA的表达.结果罗格列酮加吡喹酮治疗组小鼠肝脏的炎性反应和纤维化病理改变较其他模型组轻(P＜0.05).感染对照组NF-κB活性(141.11±15.37)最强,明显高于其余各组(正常对照组78.89±18.12;吡喹酮组112.89±20.17罗格列酮组108.89±20.47;罗格列酮加吡喹酮组88.89±19.34)(P＜0.05).感染对照组[-27.315±(-6.348)].及吡喹酮治疗组[-25.647±(-5.694)]PPARγ mRNA表达较正常对照组[-16.557±(.3.022)]及罗格列酮治疗组[-18.217±(-4.498)]、罗格列酮加吡喹酮治疗组[-18.212±(-3.909)]显著减弱(P＜0.05).结论PPARγ及NF-κB在血吸虫病肝纤维化形成中起一定作用.PPARγ配体罗格列酮有明显的抗日本血吸虫病肝纤维化效应,其抗纤维化机制与PPARγ配体激活PPARγ表达的同时抑制NF-κB的活性有关.     

罗格列酮对日本血吸虫病肝纤维化小鼠肝组织核因子-κB和过氧化物酶体增殖物激活受体γ表达的影响

目的:观察日本血吸虫病肝纤维化小鼠肝脏肝组织核因子-κB(NF-κB)的活性和过氧化物酶体增殖物激活受体γ(PPARγ)的表达,及PPARγ配体罗格列酮对其表达的影响.方法:50只昆明小鼠,随机分为正常对照组、感染对照组、吡喹酮治疗组、罗格列酮治疗组及罗格列酮加吡喹酮治疗组.除正常对照组外,其余各组均建立血吸虫病肝纤维化小鼠模型.用HE染色观察肝组织光镜下的病理改变.用Western blot方法,实时荧光定量PCR反应观察小鼠肝组织NF-κB的活性变化与PPARγmRNA的表达.结果:罗格列酮加吡喹酮治疗组小鼠肝脏的炎性反应和纤维化病理改变较其他模型组轻(P＜0.05).感染对照组NF-κB活性(141.11±15.37)最强,明显高于其余各组(正常对照组:78.89±18.12;吡喹酮组:112.89±20.17:罗格列酮组:108.89±20.47;罗格列酮加吡喹酮组:88.89±19.34)(P＜0.05).感染对照组[-27.315±(-6.348)].及吡喹酮治疗组[-25.647±(-5.694)]PPARγ mRNA表达较正常对照组[-16.557±(.3.022)]及罗格列酮治疗组[-18.217±(-4.498)]、罗格列酮加吡喹酮治疗组[-18.212±(-3.909)]显著减弱(P＜0.05).结论:PPARγ及NF-κB在血吸虫病肝纤维化形成中起一定作用.PPARγ配体罗格列酮有明显的抗日本血吸虫病肝纤维化效应,其抗纤维化机制与PPARγ配体激活PPARγ表达的同时抑制NF-κB的活性有关.     

瑞巴匹特预防葡聚糖硫酸酯钠诱发的小鼠结肠炎疗效观察及作用机制初探

目的近年氧自由基在溃疡性结肠炎(UC)发病过程中作用受到关注,一种新型的黏膜保护剂瑞巴匹特被认为具有清除氧自由基的作用,有望成为治疗溃疡性结肠炎的新药物。本文观察瑞巴匹特灌肠和灌胃治疗葡聚糖硫酸酯钠(DSS)诱发的小鼠结肠炎效果并探讨可能的作用机制。方法 3%DSS予8周龄雄性BALB/c小鼠自由饮用7 d制成小鼠结肠炎模型。予DSS前5 d开始瑞巴匹特(45 mg/kg/d)灌肠或灌胃治疗直到造模结束,处死小鼠取结肠组织,测量小鼠体重、结肠长度,进行大体和病理评分,分光光度法测定髓过氧化物酶、丙二醛含量,免疫组化法测定核因子κB(NFκB)表达水平,RT-PCR法测定过氧化物酶体增殖体激活受体γ(PPARγ)mRNA表达。结果与安慰剂对照组比较,瑞巴匹特灌肠和灌胃治疗组小鼠大体和病理评分显著改善,髓过氧化物酶活性、丙二醛含量、NFκB活性明显降低,PPARγmRNA的表达显著升高。结论瑞巴匹特可有效预防DSS诱发的小鼠结肠炎,其抑制炎症作用至少部分与清除氧自由基,从而维持局部PPARγ表达和抑制NFκB活性有关。     

罗格列酮在人结肠癌氟尿嘧啶化疗增敏作用中对细胞凋亡的影响

目的 探讨过氧化物酶体增殖因子活化受体γ(peroxisome proliferator-activated receptor gammar,PPARγ)配体罗格列酮对人结肠癌氟尿嘧啶化疗增敏作用中细胞凋亡的影响.方法 体外培养人结肠癌HT-29细胞,分别或联合应用不同浓度的罗格列酮、氟尿嘧啶(fluorouracil,5-Fu)处理HT-29细胞,PI染色流式细胞术(FCM)分析、吖啶橙/溴乙啶(AO/EB)荧光染色法观察细胞凋亡率.用Western印迹法检测HT-29细胞PPARγ、NF-κB、Bcl-2、Bax的表达.结果 (1)流式细胞术和AO/EB荧光双染色法结果显示:5-Fu能明显诱导HT-29细胞凋亡,呈剂量依赖性.3.0,6.0,12.0 μg/L处理HT-29细胞72 h,细胞凋亡率分别为13.91%,18.16%,23.14%,罗格列酮亦能诱导HT-29细胞凋亡,呈剂量依赖性.1.0,10.0,100.0 μmol/L罗格列酮处理HT-29细胞72 h后,细胞凋亡率分别为1.44%,2.34%,14.13%.无细胞毒浓度的罗格列酮能显著促进5-Fu诱导HT-29细胞凋亡.1.0 μmol/L罗格列酮与12.0 μg/L 5-Fu合用使HT-29细胞凋亡率高达48.41%.(2)Werstern印迹法结果显示HT-29细胞表达PPARγ,罗格列酮作用HT-29细胞后上调PPARγ和Bax蛋白的表达,下调NF-κB、Bcl-2蛋白的表达,且呈浓度依赖方式(P<0.05).结论 (1)无细胞毒浓度下(1.0 μmol/L)罗格列酮能促进5-Fu诱导HT-29细胞凋亡.(2)罗格列酮的化疗增敏作用中对细胞凋亡的影响可能与活化PPARγ,下调NF-κB、Bcl-2蛋白表达,上调Bax蛋白表达有关.     

罗格列酮对非酒精性脂肪性肝炎大鼠环氧合酶-2的调节

目的 探讨罗格列酮在治疗非酒精性脂肪性肝炎(NASH)大鼠中对过氧化物酶体增殖物激活受体(PPARγ)、核因子(NF)-κB、环氧合酶(COX)-2的影响.方法 将30只SD大鼠均分为正常组、模型组和罗格列酮治疗组,除对照组外,其余两组予高脂连续饲养12周复制非酒精性脂肪性肝炎(NASH)模型.从第12周开始治疗组每天给予罗格列酮4 mg/kg灌胃8周.第20周末处死动物,收集血清和肝组织,检测肝功能、血脂、糖代谢、氧化还原指标.采用HE和Masson染色观察肝脏病理变化.ELISA法检测血清肿瘤坏死因子-α和前列腺素E2水平.免疫组化法观察肝组织PPARγ、NF-κB和COX-2表达,荧光定量PCR和Western印迹法检测肝COX-2基因和蛋白表达变化.结果 与模型组相比,治疗组脂肪变性、炎性反应和纤维化改善明显(P值均<0.05).同时模型组空腹血糖、血清胰岛素、胰岛素抵抗指数(HOMA-IRI)升高,血清和肝组织脂代谢紊乱,总胆固醇、三酰甘油、低密度脂蛋白胆固醇、游离脂肪酸(FFA)升高,高密度脂蛋白胆固醇下降.治疗组在罗格列酮治疗后上述指标均明显好转.与模型组相比,治疗组丙氨酸转氨酶和天冬氨酸转氨酶明显下降,血清和肝组织总抗氧化能力、超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶明显升高,丙二醛明显下降.免疫组化显示模型组肝PPARγ表达下降、NF-κB和COX-2表达升高.定量PCR和Western印迹法显示模型组肝COX-2表达(0.57±0.08和2.83±0.24)较正常组(0.38±0.03和1.00±0.03)升高(P值分别=0.000和0.004),治疗组COX-2基因和蛋白均明显下降(1.84±0.13和0.55±0.06,P值均<0.01).结论 罗格列酮可减轻氧化应激和胰岛素抵抗,可用于治疗NASH.其机制可能是通过激活PPARγ后抑制NF-κB和COX-2表达实现.     

罗格列酮对人结肠癌裸鼠移植瘤生长作用研究

目的观察过氧化物酶体增殖物激活受体的配体罗格列酮（ROZ）对人结肠癌细胞系HT-29裸鼠移植瘤的作用,探讨ROZ活化PPARγ,下调NFκB,从而诱导人结肠癌细胞凋亡的作用机制。方法体外培养人结肠癌HT-29细胞,建立人结肠癌细胞HT-29裸鼠移植瘤模型,20只荷瘤裸鼠随机分组进行实验。Western Blot法分析PPARγ、NF-κB、Bcl-2、bax蛋白表达的影响及PPARγ活化依赖性。结果 ROZ能抑制裸鼠移植瘤的生长。结论 ROZ通过上调PPARγ蛋白表达,下调NF-κB蛋白表达,抑制人结肠癌裸鼠移植瘤生长。     

Toll样受体4、CD14和核因子-κB在溃疡性结肠炎中的表达及临床意义

Toll样受体(toll likereceptors,TLR)是1997年发现的天然免疫系统中的细胞跨膜受体,可与病原识别模式分子结合,在MD2、CD14辅助下激活下游信号传导分子,最终导致核因子(NF)κB激活,引发炎症介质表达,成为联系天然免疫与获得性免疫的纽带。本研究检测活动期溃疡性结肠炎(UC)肠黏膜TLR4、CD14与NFκB的表达并将其与疾病活动度及病理分级相比较,以探讨它们在UC发病机制中的作用。一、材料和方法1.研究对象:UC组选择2003年3月-2004年2月在四川大学华西医院明确诊断的UC患者44例,男32例,女12例,均为活动期,符合2000年全国炎症性肠病学…     

核因子-κB的表达在溃疡性结肠炎发病机制中的意义

背景:溃疡性结肠炎(UC)的病因和发病机制迄今尚未明确。研究显示转录因子核因子(NF)-κB与炎症性肠病关系密切。目的:观察UC患者病变结肠黏膜组织NF-κB的表达及其与UC病情活动性和严重性的关系,探讨NF-κB 在UC发病机制中的意义。方法:选择UC患者34例,应用免疫组化方法检测病变结肠黏膜组织NF-κB的表达,并与正常对照组(n=26)进行比较。分析NF-κB的表达与UC病情轻重、内镜分级、组织学分级和病变部位之间的关系。结果:正常结肠黏膜组织无或仅有弱阳性NF-κB p65表达,UC结肠黏膜组织的表达水平显著高于正常对照组(5．2± 2．7对1.0±0．9,P<0．01)。轻症与重症(3．5±2．0对6．1±3．2,P<0．05)以及不同内镜分级(Ⅰ级与Ⅱ级:3.3±1．9对5．7± 2．4,P<0．05;Ⅰ级与Ⅲ级:3．3±1．9对7．3±3．5,P<0．01)、不同组织学分级(Ⅰ级与Ⅱ级:3．7±2．1对5．9±2．4,P<0．05;Ⅰ级与Ⅲ级:3．7±2．1对7．4±4．0,P<0．01)和不同病变部位(直乙状结肠炎与全结肠炎:4．5±2．5对6．7±3．4,P<0．05)UC间 NF-κB p65的表达水平均有显著差异。结论:UC患者病变结肠黏膜组织NF-κB表达水平显著增高,提示NF-κB与UC 关系密切,在UC的发病机制中具有重要地位。NF-κB的表达水平可作为评价UC病情活动性和严重性的指标之一。     

罗格列酮治疗实验性小鼠结肠炎疗效观察

背景：溃疡性结肠炎迁延且传统内外科治疗效果均不理想，寻找新型而有效的药物一直是该领域研究的热点。目的：观察过氧化物酶体增生物激活受体（PPAR）－γ配体罗格列酮治疗葡聚糖硫酸钠（DSS）诱导小鼠结肠炎的疗效。方法：小鼠自由饮用5％DSS7天产生急性炎症模型，有半稀便、腹泻、大便隐血（＋）和肉眼血便症状之一者纳入研究，此后继续饮用自来水4天产生慢性炎症模型。实验动物分为预防组、急性炎症组和慢性炎症组3组，各组再分为实验组（罗格列酮治疗）、对照组1（柳氮磺胺吡啶比较）和对照组2（甲基纤维素治疗）。观察指标包括疾病活动指数（DAI）、结肠组织学评分、结肠上皮p65（免疫组化法）和肿瘤坏死因子（TNF）－αmRNA（原位杂交法）的表达。结果：罗格列酮能减少DSS诱导结肠炎的DAI和结肠组织学评分，同时降低结肠上皮p65和TNF－αmRNA的表达。结论：罗格列酮能有效预防和缓解DSS诱导的小鼠结肠炎，其作用机制可能包括抑制促炎症因子的表达。     

A clinical trial of combined use of rosiglitazone and 5-aminosalicylate for ulcerative colitis

AIM： To investigate the therapeutic effects of the combined use of rosiglitazone and aminosalicylate on mild or moderately active ulcerative colitis （UC）. METHODS： According to the national guideline for diagnosis and treatment of inflammatory bowel disease （IBD/ in China, patients with mild or moderately active UC in our hospital were selected from July to November, 2004. Patients with infectious colitis, amoebiasis, or cardiac, renal or hepatic failure and those who had received corticosteroid or immunosuppressant treatment within the last month were excluded. Following a quasi-randomization principle, patients were allocated alternatively into the treatment group （TG/ with rosiglitazone 4 mg/d plus 5-ASA 2 g/d daily or the control group （CG/with 5-ASA 2 g/d alone, respectively, for 4 wk. Clinical changes were evaluated by Mayo scoring system and histological changes by Truelove-Richards＇ grading system at initial and final point of treatment. RESULTS： Forty-two patients completed the trial, 21 each in TG and CG. The Mayo scores in TG at initial and final points were 5.87 （range： 4.29-7.43/ and 1.86 （range： 1.03-2.69/ and those in CG were 6.05 （range： 4.97-7.13/and 2.57 （range： 1.92-3.22/respectively. The decrements of Mayo scores were 4.01 in TG and 3.48 in CG, with a remission rate of 71.4% in TG and 57.1% in CG, respectively. Along with the improvement of disease activity index （DAI/, the histological grade improvement was more significant in TG than in CG （P 〈 0.05/. CONCLUSION： Combined treatment with rosiglitazone and 5-ASA achieved better therapeutic effect than 5-ASA alone without any side effects. Rosiglitazone can alleviate colonic inflammation which hopefully becomes a novel agent for UC treatment.     

5-Aminosalicylic Acid Enemas in Refractory Distal Ulcerative Colitis: A Randomized, Controlled Trial

5-Aminosalicylic acid (5-ASA), the presumed active moiety of sulfasalazine, has shown clinical efficacy when administered per rectum as initial therapy to patients with distal ulcerative colitis. We report the results of a randomized double-blind trial comparing nightly retention of a 4-g 5-ASA enema with continued administration of hydrocortisone enemas in 18 patients with persistent active distal ulcerative colitis after at least a 3-wk course of treatment with 100-mg hydrocortisone enemas with or without oral sulfasalazine. Continuation of hydrocortisone enemas rather than placebo was used in the control group to reflect the realistic alternative therapy likely to be employed in current practice. Response to therapy was assessed after 3 wk by comparing pretreatment and posttreatment point scores of clinical, sigmoidoscopic, and histological severity. Improvement in clinical score was achieved in seven of nine 5-ASA enema-treated patients versus one of nine hydrocortisone enema-treated patients (p less than 0.05). Sigmoidoscopic and histological improvement generally paralleled clinical improvement. We conclude that in patients with distal ulcerative colitis unresponsive to standard therapy, treatment with 5-ASA enemas results in significant short-term clinical and sigmoidoscopic improvement in a majority of cases. Moreover, a significantly greater number of refractory patients improve when switched to 5-ASA enemas than when continued on standard therapy.     

Measurement of colonic mucosal concentrations of 5-aminosalicylic acid is useful for estimating its therapeutic efficacy in distal ulcerative colitis: comparison of orally administered mesalamine and sulfasalazine

OBJECTIVES: Oral 5-aminosalicylic acid (5-ASA) preparations have been used frequently in the treatment of ulcerative colitis. However, there have been few reports investigating the relationship between colonic mucosal concentrations of 5-ASA and its clinical efficacy when oral sulfasalazine or 5-ASA compounds were administered. The aim of this study is to compare the mucosal concentrations of 5-ASA ensured by sulfasalazine or mesalamine, and to define the clinical significance of the measurement of 5-ASA concentrations in the treatment of distal ulcerative colitis. MATERIALS AND METHODS: Biopsies were taken from the rectum and sigmoid colon of the oral sulfasalazine group (n = 13) and the slow-release 5-ASA (mesalamine) group with (n = 5) or without (n = 11) rectal administration of 5-ASA. High-pressure liquid chromatography was used to measure the tissue concentrations of 5-ASA and its metabolites. We compared the 5-ASA concentrations of the sulfasalazine group with the mesalamine group. Furthermore, we analyzed the relationship between tissue 5-ASA concentrations and the Disease Activity Index (DAI). RESULTS: The concentrations of 5-ASA and acetyl-5-ASA in the sulfasalazine group were higher than those in the group taking oral mesalamine alone (p < 0.01). The concentration of 5-ASA was much higher in the patients who received oral and rectal mesalamine in an enema than in the patients who had oral mesalamine alone. There was a significant inverse correlation between the DAI and concentrations of 5-ASA in the rectum (r = 0.712, p < 0.001). CONCLUSIONS: We demonstrated that the colonic mucosal concentration of 5-ASA was significantly higher in the sulfasalazine group than in the mesalamine group. Furthermore, the concentrations of mucosal 5-ASA may be a good marker for the estimation of its efficacy in the treatment of ulcerative colitis.     

Putting rectal 5-aminosalicylic acid in its place: the role in distal ulcerative colitis

Oral aminosalicylates such as sulfasalazine and mesalamine are widely prescribed for the treatment of mild or moderately active distal ulcerative colitis. However, a critical review of the literature demonstrates that rectal 5-aminosalicylic acid (5-ASA) is the optimal therapy for this disease. Meta-analyses of published trials show that rectally delivered 5-ASA is superior to placebo and to conventional rectal corticosteroids in inducing remission of distal ulcerative colitis, whereas the combination of rectal 5-ASA with a rectal corticosteroid or oral aminosalicylate is superior to rectal 5-ASA alone. For maintaining remission of distal ulcerative colitis, rectal 5-ASA is significantly better than placebo and at least as effective as oral 5-ASA. The dosage forms available for rectal delivery include suppositories, foams, and liquid enemas, and selection among these preparations should be guided by the proximal extent of disease and patient preference. The efficacy of rectal 5-ASA is complemented by its low rate of reported adverse effects, which may reflect its reduced potential for systemic absorption. This review summarizes the evidence supporting the role of rectal 5-ASA as a first-line therapy for mild or moderately active distal ulcerative colitis, and offers guidelines for its use.     

The contribution of sulphate reducing bacteria and 5-aminosalicylic acid to faecal sulphide in patients with ulcerative colitis

BACKGROUND: Butyrate oxidation within the colonocyte is selectively inhibited by hydrogen sulphide, reproducing the metabolic lesion observed in active ulcerative colitis. AIMS: To study generation of hydrogen sulphide by sulphate reducing bacteria (SRB) and the effects of 5-aminosalicylic acid (5-ASA) in patients with ulcerative colitis in order to identify a role of this noxious agent in pathogenesis. PATIENTS: Fresh faeces were obtained from 37 patients with ulcerative colitis (23 with active disease) and 16 healthy controls. METHODS: SRB were enumerated from fresh faecal slurries and measurements made of sulphate reducing activity, and sulphate and hydrogen sulphide concentrations. The effect of 5-ASA on hydrogen sulphide production was studied in vitro. RESULTS: All controls and patients with active ulcerative colitis carried SRB and total viable counts were significantly related to the clinical severity grade. SRB were of two distinct types: rapidly growing strains (desulfovibrios) which showed high sulphate reduction rates, present in 30% of patients with ulcerative colitis and 44% of controls; and slow growing strains which had little activity. In vitro, 5-ASA inhibited sulphide production in a dose dependent manner; in patients with ulcerative colitis not on these drugs faecal sulphide was significantly higher than in controls (0.55 versus 0.25 mM, p=0.027). CONCLUSIONS: Counts and carriage rates of SRB in faeces of patients with ulcerative colitis are not significantly different from those in controls. SRB metabolism is not uniform between strains and alternative sources of hydrogen sulphide production exist in the colonic lumen which may be similarly inhibited by 5-ASA. The evidence for hydrogen sulphide as a metabolic toxin in ulcerative colitis remains circumstantial.     

Optimum dosage of 5-aminosalicylic acid as rectal enemas in patients with active ulcerative colitis.

5-Aminosalicylic acid (5-ASA), the active moiety of sulphasalazine (SASP), was given as a rectal enema to patients with mild to moderate distal ulcerative colitis to determine the minimum effective dosage. A double blind study was carried out using enemas containing 1, 2, or 4 g or 5-ASA or placebo for a one month treatment period. One hundred and thirteen patients with ulcerative colitis attending our outpatient clinic volunteered to participate. Clinical, sigmoidoscopic, and histological assessments were carried out at the beginning of the study and after 15 and 30 days of treatment. All patients who received 5-ASA enemas showed significantly better results than those who received a placebo enema (p less than 0.001) but no difference was detected among the patients receiving differing concentrations of 5-ASA. This study suggests that 1 g 5-ASA (in a 100 ml enema) is a sufficient dosage for patients with a mild to moderate attack of ulcerative colitis.     

Oral 4-aminosalicylic acid versus 5-aminosalicylic acid slow release tablets. Double blind, controlled pilot study in the maintenance treatment of Crohn's ileocolitis.

4-Aminosalicylic acid (4-ASA) has been suggested as an effective treatment for both active and quiescent ulcerative colitis. 5-Aminosalicylic acid (5-ASA) is well accepted for the maintenance treatment of inactive ulcerative colitis. Moreover, recent studies suggest that 5-ASA may also be effective in maintaining remission in Crohn's colitis. As treatment with 4-ASA may result in less side effects, the efficacy of a one year's maintenance treatment with oral 4-ASA (1.5 g/d, slow release tablets, n = 19) and oral 5-ASA (1.5 g/d, slow release tablets, n = 21) was compared in a double blind, randomised trial in patients with quiescent Crohn's ileocolitis. Patients with ileocolonic or colonic involvement were enrolled if in stable remission for more than two months but less than one year. Baseline demography and clinical severity were similar in both groups. Total colonoscopy and ileoscopy were performed at enrollment and at the end of the study. After one year seven of 19 patients receiving 4-ASA (36%) and 8 of 21 receiving 5-ASA (38%) had developed a clinical relapse, as defined by a rise in the Crohn's disease activity index (CDAI) of more than 100 points to values higher than 150. The relapse rates between the 4-ASA and the 5-ASA groups were not statistically different although no comparison with the spontaneous relapse rate in a placebo group could be made. Clinical relapse was accompanied by a statistically significant rise in serum concentrations of soluble interleukin 2 receptor and by an increased percentage of activated peripheral blood T cells. There were no statistical differences between the 4-ASA and the 5-ASA groups regarding the height of rise in CDAI or of soluble interleukin 2 receptor concentrations during relapse, thus showing a similar severity relapsed disease activity. In conclusion, 4-ASA maybe as effective as 5-ASA in the maintenance treatment of quiescent Crohn's disease and there were no differences in the severity of relapse between both treatment groups.     

Anti-inflammatory effect of Diammonium Glycyrrhizinate in a rat model of ulcerative colitis

AIM: To explore the anti-inflammatory mechanism of Diammonium Glycyrrhizinate in a rat model of ulcerative colitis induced by acetic acid. METHODS: Spragur-Dawley female rats were divided into four groups: Diammonium Glycyrrhizinate group, dexamethasone group, acetic acid control and normal control group. Colonic inflammation was evaluated by disease activity index, gross morphologic damage, histological injury and colonic myeloperoxidase activity. Immunohistochemistry was used to detect the expression of NF-κB, TNF-αand ICAM-1 in colonic mucosa. RESULTS: Compared to the acetic acid control, both Diammonium Glycyrrhizinate and dexamethasone showed a significant anti-inflammatory effect (P < 0.01). The expression of NF-κB, TNF-a and ICAM-1 in colonic mucosa was significantly lower in the Diammonium Glycyrrhizinate group and dexamethasone group than in the acetic acid group. CONCLUSION: Diammonium Glycyrrhizinate could reduce inflammatory injury in a rat model of ulcerative colitis. This may occur via suppression of NF-κB, TNF-a and ICAM-1 in colonic mucosa.     

The role of aminosalicylates in the treatment of ulcerative colitis

Aminosalicylates (5-ASA, sulfasalazine and mesalazine) play a central role in the treatment of ulcerative colitis (UC). For acute treatment of mild to moderate flares and in maintenance treatment, their efficacy has been established. Since ulcerative colitis is limited to the distal colon in two thirds of the patients, topical therapy also plays an important role. In mild/moderate active disease 5-ASA 4 g/d is as effective as oral corticosteroids. Ulcerative proctitis is treated with 2 x 500 mg or 1 x 1 g suppositories and proctosigmoiditis with 1 to 4 g enemas. Oral 5-ASA is also safe in maintenance treatment and is generally well tolerated. The risk of colorectal tumours is increased in patients with longstanding ulcerative colitis and epidemiological evidence indicates that chronic 5-ASA treatment reduces this risk. However, at present there is insufficient evidence to maintain patients on life-long 5-ASA maintenance treatment for this indication.     

Effect of aminophenols (5-ASA and 4-ASA) on colonic interleukin-1 generation.

The effect of 5-ASA and 4-ASA, drugs used for the treatment of inflammatory bowel disease, on modulation of experimental colitis and on colonic generation of interleukin-1 was evaluated. Three weeks of treatment with 5-ASA or 4-ASA (50 micrograms/kg) and one week of treatment with 5-ASA significantly decreased colonic interleukin-1 generation and the extent and severity of inflammation in a rat model of colitis induced by trinitrobenzene sulphonic acid. Colonic biopsies were obtained from patients with active ulcerative colitis and organ cultured 24 hours in the absence or presence of the following drugs: sulphasalazine, sulphapyridine, 5-ASA and 4-ASA (25-100 micrograms/ml). Interleukin-1 content in tissue cultured in the presence of 5-ASA (100 micrograms/ml) was two-thirds of its content in tissue cultured in drug free medium and its release into the medium was decreased by 50%. Sulphasalazine 50 micrograms/ml significantly decreased by 33% the tissue content but did not affect interleukin-1 release and a higher dose was not more effective. Sulphapyridine and 4-ASA in doses up to 100 micrograms/ml did not affect either interleukin-1 colonic content or its release into the culture medium. We conclude that pharmacological suppression of colonic interleukin-1 generation may be one, although not the sole mechanism to explain the therapeutic efficacy of 5-ASA in the treatment of inflammatory bowel disease.