不同营养治疗途径对重症急性胰腺炎大鼠血浆氨基酸谱和电解质的影响

目的比较不同配方肠内营养(EN)和肠外营养(PN)制剂对重症急性胰腺炎(SAP)大鼠血浆氨基酸谱和电解质水平的影响。方法建立大鼠SAP模型,根据SAP营养代谢配制专用EN配方(EN-S)和含益生元(PRE)的EN配方(RPE-EN)。40只大鼠随机分为正常对照组(A组)、SAP+EN-S组(B组)、SAP+PRE-EN组(C组)、SAP+商品EN组(D组)和SAP+PN组(E组),营养治疗持续7 d,检测血浆氨基酸谱和电解质水平。结果B~E组主要氨基酸和总氨基酸水平显著低于A组(P<0.05),D组天门冬氨酸、蛋氨酸和赖氨酸水平显著低于B组(P<0.05)和C组,而谷氨酸、精氨酸、丙氨酸和苯丙氨酸显著低于C组(P<0.05),低于B组但无显著性差异;B~E组血清铁显著低于A组(P<0.05),D组的血清铁显著低于C组(P<0.05),除C组外,其余各组的血浆钠显著低于A组。结论EN-S配方在提高某些氨基酸水平上作用优于商品EN;含PRE微生态营养制剂具有改善蛋白质代谢和电解质平衡的作用;短期应用EN和PN对SAP动物蛋白质代谢和电解质平衡作用无显著性差异。     

早期肠内及肠外营养支持对老年胃癌术后的运用分析

目的:探讨早期肠内及肠外营养支持对老年胃癌术后的运用,为改善患者的预后提供临床指导。方法:选取我院2008年2月~2014年2月收治的152例老年胃癌患者,分别纳入肠内营养(Enteral nutrition,EN)组(51例)、肠外营养(Parenteral nutrition,PN)组(51例)及EN联合PN组(50例),比较各组患者术后并发症、营养指标、血清指标及住院情况等,分析老年胃癌术后的最佳营养支持方案。结果:EN组胃肠道功能恢复时间为(46.3±5.2)h,PN组为(51.4±7.3)h,EN联合PN组为(41.9±4.4)h,EN联合PN组胃肠道功能恢复时间显著低于其他两组(P0.05);三组患者术后白蛋白、转铁蛋白、前白蛋白及CD8测定值无明显统计学差异(P0.05),EN联合PN组血清C反应蛋白、CD4显著低于其他两组,CD3和CD4/CD8显著高于其他两组(P0.05);EN联合PN组感染性并发症发生率及住院时间均显著低于其他两组(P0.05),其治疗费用介于EN组和PN组之间。结论:肠内联合肠外序贯营养支持较单纯肠内营养或肠外营养支持具有高效、合理、经济、安全等多种优势,能够促进患者消化吸收功能的恢复,改善老年胃癌患者预后和生存质量,值得各级医院推广应用。     

肠内营养联合益生菌对直肠恶性肿瘤术后大鼠肠粘膜屏障及血清炎症因子的影响

摘要 目的：研究肠内营养（enteral nutrition, EN）联合益生菌对直肠恶性肿瘤术后大鼠肠粘膜屏障及血清炎症因子的影响。方法：选取32只SPF级雄性SD大鼠,随机分对照组、模型组、EN组和EC组,每组8只。模型组、EN组和EC组建立直肠恶性肿瘤术后模型,EN组灌胃给予肠内营养混悬液,EC组灌胃肠内营养混悬液加益生菌颗粒,对照组和模型组灌胃同体积的生理盐水,四组大鼠均连续灌胃7 d。观察各组大鼠小肠超微结构;检测occludin蛋白、D-乳糖及炎症因子的表达水平。结果：模型组大鼠小肠上皮细胞紧密连接和绒毛结构遭破坏,EN组和EC组与模型组相比有明显改善。与对照组相比,模型组大鼠occludin蛋白和抑炎因子IL-10的表达水平均较低,D-乳糖、血清白介素1β（interleukin-1β, IL-1β）和肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）的表达水平较高（P＜0.05）;与模型组相比,EN组和EC组的occludin蛋白和IL-10的表达水平较高,D-乳糖、IL-1β和TNF-α的表达水平较低（P＜0.05）;与EN组相比,EC组occludin蛋白和IL-10的表达水平较高,D-乳糖、IL-1β和TNF-α的表达水平较低（P＜0.05）。结论：肠内营养联合益生菌可有效改善直肠恶性肿瘤术后大鼠的肠道屏障功能,提高occludin蛋白的表达,降低D-乳糖的表达,降低促炎因子IL-1β和TNF-α的表达同时升高抑炎因子IL-10的表达。     

肠内外营养联合支持对老年消化道肿瘤患者术后营养免疫状况的影响

目的:观察对比老年消化道肿瘤患者术后给予肠内营养(EN)、肠外营养(PN)联合应用(EN+PN)和单独采用PN对患者营养和免疫状况的影响。方法:选择我院2010年6月~2014年10月收治的老年消化道肿瘤患者60例,采用随机数字表法将所有患者分为PN组27例和PN+EN组33例。检测并比较两组患者血红蛋白(Hb)、血清白蛋白(Alb)、前白蛋白(Pre Alb)、转铁蛋白(TFN)、T淋巴细胞亚群及体重(BW)指标及术后并发症。结果:术后第8天较术前第七天两组患者血清Alb、Pre Alb、TFN均出现明显上升(P0.05),但两组间比较差异无统计学意义(P0.05),两组患者Hb和BW均略有下降,差异不存在统计学意义(P0.05);术后第8天EN+PN组患者的CD3+、CD4+/CD8+基本恢复到第七天水平,而PN组患者CD3+、CD4+/CD8+均低于第七天水平,差异存在统计学意义(P0.05);术后En+PN组较PN组,肛门排气时间较早、住院时间较短,差异均存在统计学意义(P0.05);两组均未发现严重并发症。结论:PN+EN和PN营养支持均可以改善老年消化道肿瘤患者术后的营养状况,但PN+EN更有利于提高患者免疫力,缩短住院时间。因此,PN+EN具有营养丰富、安全可靠的优点,值得临床推广应用。     

胃癌全胃切除术后早期肠内营养的临床研究

目的:探讨胃癌全胃切除术后早期肠内营养(EN)和全肠外营养(PN)对术后营养状况和免疫功能等状况恢复的影响.方法:50例胃癌全胃切除术后患者随机分为EN组和PN组,每组各25例.EN组术中放置空肠造口管,术后24 h以内管喂肠内营养液肠内高营养多聚合剂(能全力),PN组给予等氮、等热量的标准PN,总热量为125 kJ/(kg·d)术前1d、术后第1、10d观察并比较两组病人手术前、后的营养和免疫指标、术后肠鸣音恢复、肛门排气时间和并发症发生的情况.结果:所有病例无手术死亡、无严重并发症发生;两组病人术后营养支持的营养及免疫指标明显改善(P＜0.05),EN组前白蛋白和免疫指标较PN组明显提高(P＜0.05);EN组较PN组术后胃肠功能恢复的更早,并发症的发生率亦明显减低,同时住院时间短.结论:胃癌全胃切除术后早期予肠内营养安全、有效,既能促进胃肠道功能早期恢复,又可改善患者术后营养状况和免疫功能,是值得推广的营养支持方式.     

早期肠内肠外营养支持对脑出血术后患者营养状况的影响

目的：比较脑出血患者术后肠外营养与肠内营养支持的营养支持效果。方法：将高压氧科脑出血患者分为肠外营养（PN）组、肠内营养医用制剂（EN1）组、肠内营养医用食品（EN2）组,比较3组患者营养支持治疗3w后血清白蛋白（ALB）、甘油三酯（TG）及CD3+、CD4+等免疫生化指标,观察恶心、呕吐与腹泻等消化道症状,并测量AMC、TSF值。结果：3组生化指标ALB、TG、CD3+、CD4+等指标治疗前比较无明显差异（P＞005）,营养支持后比较,PN组血清ALB水平最低,EN2组血清ALB水平最高,差异具有显著性意义（P＜005）;PN组血清TG水平较EN1、EN2组明显增高,差异具有显著性意义（P＜001）。EN2组CD3+、CD4+较PN及EN1组明显升高差异具有显著性意义（P＜005）。EN组平均住院时间、治疗费用明显低于PN组,EN2组低于EN1组,3组间差异具有显著统计学意义。结论：使用肠内营养制剂虽无改善脑出血术后患者的远期疗效的明确依据,但可在急性期治疗中减少并发症及住院时间、降低治疗总费用。与肠外营养相比,早期肠内营养支持可较好地改善患者营养状况。     

经胃镜鼻空肠置管早期肠内营养与肠外营养对急性重症胰腺炎患者血糖等变化的对比研究

目的:探讨经胃镜鼻空肠置管肠内营养与肠外营养对重症胰腺炎患者血糖及相关指标的影响.方法:将32例重症胰腺炎患者随机分为早期肠内营养组(EEN,18例)和肠外营养组(PN,14例).详细记录治疗期间的血糖波动,第4d、10d营养指标和淀粉酶等变化,并观察临床恢复情况.结果:早期肠内营养组血糖水平波动较肠外营养组平稳(P＜0.01).入院第4天EEN组患者的各项营养指标和淀粉酶指标恢复明显高于PN组患者(P＜0.01).并发症发生率EEN组少于PN组,差异有显著性(P＜0.01).结论:经胃镜鼻空肠置管早期肠内营养对重症胰腺炎患者营养支持的较好方法,方便血糖调控,同时可促进机体康复,减少并发症的发生.     

经胃镜鼻空肠置管早期肠内营养与肠外营养对急性重症胰腺炎患者血糖等变化的对比研究

目的:探讨经胃镜鼻空肠置管肠内营养与肠外营养对重症胰腺炎患者血糖及相关指标的影响。方法:将32例重症胰腺炎患者随机分为早期肠内营养组(EEN,18例)和肠外营养组(PN,14例)。详细记录治疗期间的血糖波动,第4d、10d营养指标和淀粉酶等变化,并观察临床恢复情况。结果:早期肠内营养组血糖水平波动较肠外营养组平稳(P<0.01)。入院第4天EEN组患者的各项营养指标和淀粉酶指标恢复明显高于PN组患者(P<0.01)。并发症发生率EEN组少于PN组,差异有显著性(P<0.01)。结论:经胃镜鼻空肠置管早期肠内营养对重症胰腺炎患者营养支持的较好方法,方便血糖调控,同时可促进机体康复,减少并发症的发生。     

全肠内营养治疗利于提升克罗恩病患儿的营养指标及生理指标

为探讨全肠内营养治疗小儿克罗恩病的临床效果及其护理方法,本研究选取中国医科大学附属盛京医院2014年1月至2016年1月期间收治的60例克罗恩病患儿,采用随机数字表法分为肠内营养治疗的30例患儿(EN组)、肠外营养患儿30例(PN组),对比两种方法的临床疗效差异,并分析实施肠内营养治疗患儿的护理方法。结果表明,治疗前,EN组和PN组患儿的身高、体质量、白蛋白(albumin, ALB)、血红蛋白(hemoglobin, Hb)、前白蛋白、转铁蛋白测定值差异不具有统计学意义(p>0.05);治疗后,EN组患儿的体质量、ALB、Hb、前白蛋白、转铁蛋白测定值均显著地高于PN组(p<0.05);治疗前,EN组和PN组患儿的血沉(erythrocyte sedimentation rate, ESR)、C反应蛋白(C-reactive protein, CRP)及儿童克罗恩病活动指数(pediatric Crohn’s disease activity index, PCDAI)评分差异不具有统计学意义(p>0.05);治疗后,EN组患儿的CRP及PCDAI评分均显著地低于PN组(p<0.05),两组的ESR测定值差异不具有统计学意义(p>0.05)。本研究初步表明,全肠内营养治疗小儿克罗恩病的效果优于肠外营养,在治疗过程中同时应加强护理。     

早期肠内营养联合谷氨酰胺对重症急性胰腺炎患者的临床效果

目的:评价早期肠内营养联合谷氨酰胺对老年重症急性胰腺炎(SAP)营养状况的影响效果。方法:将我院收治的106例老年SAP患者随机分为观察组与对照组。观察组给予早期肠内营养联合谷氨酰胺营养支持,对照组给予完全胃肠外营养支持。观察并比较两组患者治疗前后的血淀粉酶(AMY)、尿淀粉酶(UAMY)、APACHE-Ⅱ评分、Ranson评分、血清白蛋白(ALB)、血清前白蛋白(PA)、转铁蛋白(TRF)及体重的变化情况;比较两组患者住院天数及并发症的发生率。结果:与治疗前比较,两组患者治疗后AMY、UAMY、APACHE-Ⅱ评分及Ranson评分均显著下降,且观察组低于对照组,差异具有统计学意义(P0.05);与治疗前比较,两组患者治疗后ALB、PA、TRF及体重均显著提高,且观察组高于对照组,差异具有统计学意义(P0.05);与对照组比较,观察组住院时间短,并发症发生率低,差异具有统计学意义(P0.05)。结论:早期肠内营养联合谷氨酰胺营养支持干预较完全胃肠外营养在治疗老年SAP中能有效缓解机体高分解代谢,明显改善患者营养状况,减少并发症的发生率。     

Enteral nutrients potentiate glucagon-like peptide-2 action and reduce dependence on parenteral nutrition in a rat model of human intestinal failure

Glucagon-like peptide-2 (GLP-2) is a nutrient-dependent, proglucagon-derived gut hormone that shows promise for the treatment of short bowel syndrome (SBS). Our objective was to investigate how combination GLP-2 + enteral nutrients (EN) affects intestinal adaption in a rat model that mimics severe human SBS and requires parenteral nutrition (PN). Male Sprague-Dawley rats were assigned to one of five groups and maintained with PN for 18 days: total parenteral nutrition (TPN) alone, TPN + GLP-2 (100 μg·kg(-1)·day(-1)), PN + EN + GLP-2(7 days), PN + EN + GLP-2(18 days), and a nonsurgical oral reference group. Animals underwent massive distal bowel resection followed by jejunocolic anastomosis and placement of jugular catheters. Starting on postoperative day 4, rats in the EN groups were allowed ad libitum access to EN. Groups provided PN + EN + GLP-2 had their rate of PN reduced by 0.25 ml/day starting on postoperative day 6. Groups provided PN + EN + GLP-2 demonstrated significantly greater body weight gain with similar energy intake and a safe 80% reduction in PN compared with TPN ± GLP-2. Groups provided PN + EN + GLP-2 for 7 or 18 days showed similar body weight gain, residual jejunal length, and digestive capacity. Groups provided PN + EN + GLP-2 showed increased jejunal GLP-2 receptor (GLP-2R), insulin-like growth factor-I (IGF-I), and IGF-binding protein-5 (IGFBP-5) expression. Treatment with TPN + GLP-2 demonstrated increased jejunal expression of epidermal growth factor. Cessation of GLP-2 after 7 days with continued EN sustained the majority of intestinal adaption and significantly increased expression of colonic proglucagon compared with PN + EN + GLP-2 for 18 days, and increased plasma GLP-2 concentrations compared with TPN alone. In summary, EN potentiate the intestinotrophic actions of GLP-2 by improving body weight gain allowing for a safe 80% reduction in PN with increased jejunal expression of GLP-2R, IGF-I, and IGFBP-5 following distal bowel resection in the rat.     

Aureusidin derivative CNQX inhibits chronic colitis inflammation and mucosal barrier damage by targeting myeloid differentiation 2 protein

Our previous study has found that aureusidin can inhibit inflammation by targeting myeloid differentiation 2 (MD2) protein. Structural optimization of aureusidin gave rise to a derivative named CNQX. LPS was used to induce inflammation in intestinal macrophages; flow cytometry, PI staining and Hoechst 33342 staining were used to detect the apoptotic level of macrophages; enzyme-linked immunosorbent assay (ELISA) was utilized to detect the expression level of inflammatory factors (including IL-1β, IL-18 and TNF-α); immunofluorescence staining was used to investigate the expression of MD2; Western blot was employed to measure the protein level of TLR4, MD2, MyD88 and p-P65. As a result, CNQX with IC50 of 2.5 μM can significantly inhibit the inflammatory damage of macrophages, decrease apoptotic level, reduce the expression level of inflammatory factors and simultaneously decrease the expression level of TLR4, MD2, MyD88 as well as p-P65. Caco-2 cell line was used to simulate the intestinal mucosal barrier in vitro, LPS was employed to induce cell injury in Caco-2 (to up-regulate barrier permeability), and CNQX with IC50 of 2.5 μl was used for intervention. Flow cytometry was used to detect the apoptotic level of Caco-2 cells, trans-epithelial electric resistance (TEER) was measured, FITC-D was used to detect the permeability of the intestinal mucosa, and Western blot was used to detect the expression levels of tight junction proteins (including occludin, claudin-1, MyD88, TLR4 and MD2). As a result, CNQX decreased the apoptotic level of Caco-2 cells, increased TEER value, decreased the expression levels of MyD88, TLR4 and MD2, and increased the protein levels of tight junction proteins (including occludin and claudin-1). C57BL/6 wild-type mice were treated with drinking water containing Dextran sulphate sodium (DSS) to establish murine chronic colitis model. After CQNX intervention, we detected the bodyweight, DAI score and H&E tissue staining to evaluate the life status and pathological changes. Immunohistochemistry (IHC) staining was used to detect the expression of MD2 protein, tight junction protein (including occludin and claudin-1). Transmission electron microscopy and FITC-D were used to detect intestinal mucosal permeability. Western blot was used to detect the expression levels of tight junction proteins (including occludin, claudin-1, MyD88, TLR4 and MD2) in the intestinal mucosa tissue. Consequently, CNQX can inhibit the intestinal inflammatory response in mice with colitis, inhibit the mucosal barrier injury, increase the expression of tight junction proteins (including occludin and claudin-1) and decrease the expression levels of MyD88, TLR4 and MD2. Mechanistically, pull-down and immunoprecipitation assays showed that CNQX can inhibit the activation of TLR4/MD2-NF-κB by binding to MD2 protein. Collectively, in this study, we found that CNQX can suppress the activation of TLR4 signals by targeting MD2 protein, thereby inhibiting inflammation and mucosal barrier damage of chronic colitis.     

Interleukin-2 receptor beta subunit-dependent and -independent regulation of intestinal epithelial tight junctions

Interleukin (IL)-15 is able to regulate tight junction formation in intestinal epithelial cells. However, the mechanisms that regulate the intestinal barrier function in response to IL-15 and the involved subunits of the IL-15 ligand-receptor system are unknown. We determined the IL-2Rbeta subunit and IL-15-dependent regulation of tight junction-associated proteins in the human intestinal epithelial cell line T-84. The IL-2Rbeta subunit was expressed and induced signal transduction in caveolin enriched rafts in intestinal epithelial cells. IL-15-mediated tightening of intestinal epithelial monolayers correlated with the enhanced recruitment of tight junction proteins into Triton X-100-insoluble protein fractions. IL-15-mediated up-regulation of ZO-1 and ZO-2 expression was independent of the IL-2Rbeta subunit, whereas the phosphorylation of occludin and enhanced membrane association of claudin-1 and claudin-2 by IL-15 required the presence of the IL-2Rbeta subunit. Recruitment of claudins and hyperphosphorylated occludin into tight junctions resulted in a more marked induction of tight junction formation in intestinal epithelial cells than the up-regulation of ZO-1 and ZO-2 by itself. The regulation of the intestinal epithelial barrier function by IL-15 involves IL-2Rbeta-dependent and -independent signaling pathways leading to the recruitment of claudins, hyperphosphorylated occludin, ZO-1, and ZO-2 into the tight junctional protein complex.     

舍得老酒对大鼠肠屏障功能及肠道菌群的影响

探究舍得老酒对大鼠肠屏障功能及其肠道菌群构成的影响。

将28只SPF级180～220 g SD雄性大鼠随机分为4组（n = 7）：对照组、乙醇组、舍得老酒1组及舍得老酒2组。分别灌胃生理盐水、酒精（7.6 mL/kg）及舍得老酒（3.8 mL/kg和7.6 mL/kg 2个剂量）,连续灌胃4周。检测结肠紧密连接蛋白mRNA表达水平,血清炎症相关分子水平;采用流式细胞仪检测脾脏免疫细胞水平;采用测序检测粪便肠道菌群构成。

乙醇组大鼠紧密连接蛋白mRNA表达水平较低,血清中的肿瘤坏死因子-α浓度较高,白介素10浓度较低,而舍得老酒2个剂量组均不同程度地改善了乙醇对大鼠肠屏障功能的不良反应。舍得老酒7.6 mL/kg剂量组可能通过降低CD4⁺ T细胞比例而减少炎症的发生。舍得老酒3.8 mL/kg组大鼠肠道菌群alpha多样性高于其他3组。4组大鼠肠道菌群组成具有一定差异,门水平上,乙醇组拟杆菌门相对丰度较其他组高,厚壁菌门与拟杆菌门比值（F/B）低于其他3组;属水平上,乙醇组Ruminiclostridium_6、Prevotella_9及Lachnospiraceae_NK4A136_group丰度较对照组增加,舍得老酒3.8 mL/kg组的接近对照组,乙醇组Lactobacillus丰度降低,舍得老酒3.8 mL/kg组Lactobacillus丰度增加。

低剂量组舍得老酒可改善大鼠肠屏障功能,并可通过增加肠道菌群丰度及多样性、抑制部分肠道致病菌的生长及增加有益菌,从而起到一定的调节肠道菌群的作用。

     

肠内营养支持治疗对炎症性肠病患者肠黏膜屏障功能及炎症反应的影响

目的 探讨早期肠内营养（EN）支持治疗对炎症性肠病（IBD）患者肠黏膜屏障功能及炎症反应的影响。方法 将80例IBD患者按营养支持治疗途径分为EN组（48例）和肠外营养（PN）组（32例）,在常规治疗的基础上分别给予早期EN、PN支持治疗。比较治疗前后2组患者营养学相关指标[白蛋白（ALB）、前白蛋白（PA）、转铁蛋白（TF）]、肠黏膜屏障功能指标（内毒素、D-乳酸）及炎症相关指标[C-反应蛋白（CRP）、降钙素原（PCT）、粪便钙卫蛋白（FCP）]水平。结果 治疗前,2组患者各观察指标水平差异无统计学意义（P>0.05）;治疗后,与治疗前相比,2组患者血清ALB、PA及TF水平均显著升高（P0.05）。结论 在常规治疗的基础上,早期EN支持治疗对IBD患者肠黏膜屏障功能的改善及炎症缓解作用优于PN支持治疗。     

Antinociceptive effect of VSL#3 on visceral hypersensitivity in a rat model of irritable bowel syndrome: a possible action through nitric oxide pathway and enhance barrier function

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by visceral hypersensitivity and altered bowel function. There are increasing evidences suggested that VSL#3 probiotics therapy has been recognized as an effective method to relieve IBS-induced symptoms. The aim of this study was to examine the effects of VSL#3 probiotics on visceral hypersensitivity (VH), nitric oxide (NO), fecal character, colonic epithelium permeability, and tight junction protein expression. IBS model was induced by intracolonic instillation of 4% acetic acid and restraint stress in rats. After subsidence of inflammation on the seventh experimental day, the rats were subjected to rectal distension, and then the abdominal withdrawal reflex and the number of fecal output were measured, respectively. Also, colonic permeability to Evans blue was measured in vivo, and tight junction protein expression was studied by immunohistochemistry and immunoblotting method. Rats had been pretreated with VSL#3 or aminoguanidine (NOS inhibitor) or VSL#3+ aminoguanidine before measurements. The rats at placebo group showed hypersensitive response to rectal distension (P < 0.05) and defecated more stools than control rats (P < 0.05), whereas VSL#3 treatment significantly attenuated VH and effectively reduced defecation. Aminoguanidine reduced the protective effects of VSL#3 on VH. A pronounced increase in epithelial permeability and decreased expression of tight junction proteins (occludin, ZO-1) in placebo group were prevented by VSL#3, but not aminoguanidine. VSL#3 treatment reduce the hypersensitivity, defecation, colonic permeability and increase the expression of tight junction proteins (occludin, ZO-1). As the part of this effect was lowered by NOS inhibitor, NO might play a role in the protective effect of VSL#3 to some extent.     

Polyamines are necessary for synthesis and stability of occludin protein in intestinal epithelial cells

Occludin is an integral membrane protein that forms the sealing element of tight junctions and is critical for epithelial barrier function. Polyamines are implicated in multiple signaling pathways driving different biological functions of intestinal epithelial cells (IEC). The present study determined whether polyamines are involved in expression of occludin and play a role in intestinal epithelial barrier function. Studies were conducted in stable Cdx2-transfected IEC-6 cells (IEC-Cdx2L1) associated with a highly differentiated phenotype. Polyamine depletion by alpha-difluoromethylornithine (DFMO) decreased levels of occludin protein but failed to affect expression of its mRNA. Other tight junction proteins, zonula occludens (ZO)-1, ZO-2, claudin-2, and claudin-3, were also decreased in polyamine-deficient cells. Decreased levels of tight junction proteins in DFMO-treated cells were associated with dysfunction of the epithelial barrier, which was overcome by exogenous polyamine spermidine. Decreased levels of occludin in polyamine-deficient cells was not due to the reduction of intracellular-free Ca(2+) concentration ([Ca(2+)](cyt)), because either increased or decreased [Ca(2+)](cyt) did not alter levels of occludin in the presence or absence of polyamines. The level of newly synthesized occludin protein was decreased by approximately 70% following polyamine depletion, whereas its protein half-life was reduced from approximately 120 min in control cells to approximately 75 min in polyamine-deficient cells. These findings indicate that polyamines are necessary for the synthesis and stability of occludin protein and that polyamine depletion disrupts the epithelial barrier function, at least partially, by decreasing occludin.