Epidermal growth factor partially restores colonic ion transport responses in mouse models of chronic colitis

BACKGROUND & AIMS: Epidermal growth factor receptor (EGFR) activation, which plays an important role in regulating intestinal ion transport, can alleviate clinical symptoms such as diarrhea in patients with ulcerative colitis and promote mucosal restitution in animal models of colitis. Here, we investigate whether EGFR can regulate colonic ion transport in the setting of colitis. METHODS: Distal colon from control mice and mice with colitis was retained for immunohistochemistry or mounted in Ussing chambers. Ion transport responses across the tissues to the calcium agonist carbachol and the adenosine 3',5'-cyclic monophosphate agonist forskolin were measured with or without epidermal growth factor (EGF) pretreatment. RESULTS: EGF pretreatment of normal colonic mucosa inhibited ion transport responses to carbachol and forskolin but potentiated the reduced ion transport responses seen in dextran sulfate sodium (DSS)-treated and mdr1a knockout mouse colon. Ion substitution studies and the sodium transport inhibitor amiloride showed that sodium movement primarily accounted for the potentiating effect of EGF in DSS-treated tissues, despite decreased sodium channel expression. EGF potentiation of transport responses in DSS-treated colon was completely blocked by the cytoskeletal disruptor cytochalasin D and the phosphatidylinositol 3-kinase inhibitor wortmannin, whereas the novel and conventional protein kinase C isoform inhibitor G?6850 and the extracellular signal-regulated kinase inhibitor PD98059 partially reduced EGF effects. EGFR epithelial distribution and transforming growth factor alpha expression were also altered in DSS-treated tissues. CONCLUSIONS: Chronic inflammation uncovers a potentiating effect of EGFR activation on epithelial electrogenic sodium absorption that would be expected to ameliorate diarrheal symptoms associated with colitis.     

Upregulation of 25-hydroxyvitamin D3-1α-hydroxylase by butyrate in Caco-2 cells

AIM: To investigate the possible involvement of 25-hydroxyvitamin D(3)-1(alpha)-hydroxylase [1alpha-25(OH) (2) D(3)] in butyrate-induced differentiation in human intestinal cell line Caco-2 cells. METHODS: Caco-2 cells were incubated either with 3 mmol/L butyrate and 1 micromol/L 25(OH) (2) D(3) or with 1 micromol/L 1alpha-25(OH) (2) D(3) for various time intervals ranging from 0 to 72 h. Additionally, cells were co-incubated with butyrate and either 25(OH) (2) D(3) or 1alpha-25(OH) (2) D(3). 1alpha-25(OH) (2) D(3) mRNA was determined semi-quantitatively using the fluorescent dye PicoGreen. Immunoblotting was used for the detection of 1alpha-25(OH) (2) D(3) protein. Finally, enzymatic activity was measured by ELISA. RESULTS: Both butyrate and 1alpha-25(OH) (2) D(3) stimulated differentiation of Caco-2 cells after a 48 h incubation period, while 25(OH) (2) D(3) had no impact on cell differentiation. Synergistic effects on differentiation were observed when cells were co-incubated with butyrate and vitamin D metabolite. Butyrate transiently upregulated 1alpha-25(OH) (2) D(3) mRNA followed by a timely delayed protein upregulation. Coincidently, enzymatic activity was enhanced significantly. The induction of the enzyme allowed for comparable differentiating effects of both vitamin D metabolites. CONCLUSION: Our experimental data provide a further mechanism for the involvement of the vitamin D signaling pathway in colonic epithelial cell differentiation by butyrate. The enhancement of 1alpha-25(OH) (2) D(3) followed by antiproliferative effects of the vitamin D prohormone in the Caco-2 cell line suggest that 25(OH) (2) D(3) in combination with butyrate may offer a new therapeutic approach for the treatment of colon cancer.     

Y型聚乙二醇干扰素α-2b注射液治疗HCV基因2/3型慢性丙型肝炎患者疗效和安全性的多中心随机对照试验研究*

目的 以标准剂量的聚乙二醇干扰素（PegIFN）α-2a联合利巴韦林作为阳性对照,评价新型试验药物Y型PegIFNα-2b注射液联合利巴韦林治疗2型/3型慢性丙型肝炎（CHC）患者的疗效和安全性。方法 采用多中心、随机开放、阳性药对照的Ⅲ期临床试验,筛选符合要求的2型/3型CHC患者,按照2:1的比例随机分配到Y型PegIFNα-2b组和PegIFNα-2a组,同时口服利巴韦林,疗程24 w,停药随访24 w。采用Abbott RealTime HCV Genotype II检测HCV基因型,采用Cobas TaqMan实时定量PCR法检测血清HCV RNA水平。详细记录不良事件。主要疗效指标为持续病毒学应答（SVR）,并进行非劣效检验。结果 本试验实际入组2型/3型CHC患者255例,实际治疗241例。全分析集（FAS）数据显示,158例试验组和83例对照组患者SVR分别为85.4%（95% CI 79.94%~90.94%）和79.5%（95% CI 70.84%~88.20%,P=0.2402）;对符合方案分析集（PPS）人群分析显示,试验组和对照组患者SVR分别为87.9%（95% CI 82.45%~93.27%）和85.9%（95% CI 77.82%~94.01%,P=0.7060）,率差的95%可置信区间均符合非劣效标准;对PPS人群分析显示,85.8%受试者获得了早期病毒学应答（RVR）,RVR的阳性预测值为90.1%;试验组和对照组不良事件发生率相似,分别为95.6%和95.2%,严重不良事件发生率分别为3.8%和3.6%。结论 应用PegIFNα联合利巴韦林治疗2型/3型CHC患者,新型试验药物Y型PegIFNα-2b具有与对照药物PegIFNα-2a相似的疗效和安全性。     

Association of Interleukin-1β-31C/T, -511T/C and -3954C/T Single Nucleotide Polymorphism and Their Blood Plasma Level in Acquired Aplastic Anemia

Aplastic anemia (AA) is an immune-mediated disorder in which hematopoietic stem and progenitor cells are targeted by a number of cellular and molecular pathways. This case control study aims to investigate the association of interleukin-1beta (IL-1β) gene polymorphisms, (IL-1β-31, IL-1β-511 and IL-1β-3954) and their plasma levels with acquired AA. Genotyping was done by Restricted Fragment Length Polymorphism (PCR–RFLP) method and IL-1β plasma levels were evaluated in peripheral blood using ELISA. Increased level of IL-1β was reported to be significant in cases as compared to controls. The susceptibility of developing AA was higher in the cases for IL-1β-3954 genotype. IL-1β-511 genotype showed significant association with the severity groups of AA. No significant association was noticed in responder versus non-responder group. Plasma level of IL-1β gene was found to be significantly higher in severe and very-severe group of AA versus control group. Our findings suggest that IL-1β gene and its genotypes might be involved in the pathophysiology of AA and play a central role in the etiopathogenesis of AA.     

聚乙二醇干扰素α-2a联合恩替卡韦治疗拉米夫定耐药的慢性乙型肝炎患者疗效分析*

目的 探讨聚乙二醇干扰素α-2a联合恩替卡韦治疗拉米夫定耐药的HBeAg阳性慢性乙型肝炎患者的疗效。方法 随机将85例拉米夫定耐药患者分为两组,给予45例CHB患者恩替卡韦治疗,40例患者接受恩替卡韦和聚乙二醇干扰素α-2a治疗。结果 在治疗24 w末,两组血清ALT和AST水平均较治疗前下降,在治疗48 w末,联合组血清ALT和AST水平较恩替卡韦治疗组显著降低,差异有统计学意义（P<0.05）;联合组血清HBeAg阴转和血清转换率均显著高于恩替卡韦治疗组（P<0.05）。结论 应用聚乙二醇干扰素α-2a联合恩替卡韦治疗拉米夫定耐药的HBeAg慢性乙型肝炎患者可提高HBeAg转阴率和血清转换率,治疗安全。     

Activation of the canonical Wnt/beta-catenin pathway confers growth advantages in c-Myc/E2F1 transgenic mouse model of liver cancer

BACKGROUND/AIMS: Previously, we showed that activation of the beta-catenin/Wnt pathway is a dominant event during c-Myc/E2F1 hepatocarcinogenesis. Majority of c-Myc/E2F1 HCCs displayed nuclear accumulation of beta-catenin in the absence of beta-catenin mutations, suggesting that alterations in other members of the Wnt pathway might be responsible for nuclear localization of beta-catenin. Here, we investigated the mechanisms responsible for nuclear translocation of wild-type beta-catenin and addressed the potential contribution of the Wnt pathway in c-Myc/E2F1 hepatocarcinogenesis. METHODS: Status of the members of the Wnt pathway was determined through microsatellite and Western blot analysis. RESULTS: Majority of c-Myc/E2F1 HCCs exhibited multiple abnormalities in the Wnt pathway regardless of the presence of beta-catenin mutations. The observed abnormalities included overexpression of Wnt-1, Frizzled 1 and 2 receptors, Dishevelled-1, downregulation of Secreted frizzled-related protein-1, GSK-3beta inactivation, microsatellite instability at the Axin locus as well as induction of beta-catenin target genes, such as glutamine synthetase, glutamate transporter-1, and Wisp-1. HCCs with beta-catenin activation displayed significantly higher proliferation rate and larger tumor size when compared with beta-catenin negative tumors. CONCLUSIONS: The data demonstrate that multiple abnormalities in the members of the Wnt pathway lead to nuclear accumulation of beta-catenin and suggest that activation of Wnt pathway provides proliferative advantages in c-Myc/E2F1-driven hepatocarcinogenesis.     

国产聚乙二醇化干扰素α治疗HBeAg阳性慢性乙型肝炎患者疗效研究

目的 观察国产聚乙二醇化干扰素α-2b（peg-IFN-α-2b）治疗血清HBeAg阳性的慢性乙型肝炎（CHB）患者的效果。方法 2015年1月~2017年12月纳入血清HBeAg阳性的CHB患者500例,被分为A组150例,给予国产peg-IFN-α-2b治疗,和B组350例,给予peg-IFN-α-2a治疗。两组均治疗24~48 w。在治疗结束后,随访24 w。结果 治疗前,A组血清HBV DNA定量为（6.1±0.7） lg cps/ml、谷丙转氨酶（ALT）为（81.1±29.8）u/l、体质指数为（22.1±2.9）、血清HBeAg定量为（3.1±0.6） lg s/co和HBsA定量为（4.4±0.6） IU/ml,与B组的（6.2±0.67） lg cps/ml、（80.7±27.9） U/L、（21.9±2.9）、（3.1±0.1） lg s/co和（4.4±0.5） IU/ml比,差异均无统计学意义（P>0.05）;在随访24 w结束时,A组血清ALT复常率为64.0%,血清HBV DNA阴转率为60.0%,与B组的66.9%和62.9%比,差异均无统计学意义（P>0.05）;两组不良反应发生率也无显著性相差（P>0.05）。结论 应用国产peg-IFN-α-2b治疗血清HBeAg阳性的CHB患者能获得与peg-IFN-α-2a治疗相似的疗效,但价格便宜,具有临床应用价值。     

聚乙二醇干扰素α-2a联合阿德福韦酯治疗HBeAg阳性慢性乙型肝炎患者疗效及对血清细胞因子和肝纤维化指标的影响

目的观察聚乙二醇干扰素α-2a联合阿德福韦酯治疗HBeAg阳性的慢性乙型肝炎（CHB）患者的疗效及其对血清T淋巴细胞因子和肝纤维化指标的影响。方法144例CHB患者依纳入顺序单双号被随机分为观察组和对照组,每组72例。给予对照组患者阿德福韦酯,观察组在对照组的基础上给予聚乙二醇干扰素α-2a,治疗24 w,观察两组抗病毒疗效以及血清T淋巴细胞因子白介素（IL）-2、IL-6、IL-10、γ-干扰素（INF-γ）以及血清肝纤维化指标Ⅲ型前胶原肽（PⅢP）、层粘连蛋白（LN）、透明质酸（HA）、Ⅳ型胶原(Ⅳ-C）的变化。结果在治疗24 w末,观察组患者血清HBV 转阴率、HBeAg转阴率、HBeAg血清转换率分别为72.22%、58.33%和41.67%,显著高于对照组(分别为55.56%、22.22%和20.83%,P<0.05）;观察组血清IL-2和INF-γ水平分别为（2.18±1.26） pg/ml和（99.65±11.03） pg/ml,较对照组显著升高【（1.71±1.05） pg/ml和（85.70±11.82） pg/ml,P<0.05】,而IL-6和IL-10分别为（4.53±2.15） pg/ml和（15.42±9.39） pg/ml,较对照组显著降低【（5.47±2.25） pg/ml和（20.07±13.08）pg/ml,P<0.05】;观察组HA、LN、Ⅳ-C、PⅢP分别为（127.28±59.60） μg/L、（110.52±37.39） μg/L、（116.56±28.61） μg/L和（163.65±64.38） μg/L,均较对照组显著降低【（261.35±81.46） μg/L、（162.32±38.82）μg/L、（174.13±43.05） μg/L和（212.43±64.25） μg/L,P<0.05】。结论聚乙二醇干扰素α-2a联合阿德福韦酯抗病毒疗效及改善HBeAg阳性CHB患者血清T淋巴细胞因子失衡,降低肝纤维化指标的作用优于单用阿德福韦酯者。     

拉米夫定联合聚乙二醇干扰素初始和再治疗慢性乙型肝炎合并脂肪肝疗效观察

目的分析应用拉米夫定联合干扰素治疗慢性乙型肝炎合并脂肪肝患者的疗效。方法随机纳入65例慢性乙型肝炎合并非酒精性脂肪性肝病（NAFLD）初治和52例曾接受过核苷类药物治疗失败的慢性乙型肝炎合并NAFLD患者,给予拉米夫定联合聚乙二醇干扰素α-2a（Peg-IFNα-2a）治疗48 w。采用荧光定量PCR法检测血清HBV DNA,采用微粒子酶免分析法检测血清HBV标志物。使用B超检查诊断脂肪肝。结果在治疗48 w时,初治组完全应答率为47.7%,而再治疗组为28.8%,差异显著（P<0.05）;在治疗24 w时,初治组患者血清HBV DNA低于不可检测水平发生率为41.5%,显著高于再治组的23.1%（P<0.05）,在治疗第48 w时,达到86.2%,也显著高于再治组的59.6%（P<0.05）;在治疗24 w时,两组血清HBeAg/HBeAb转换率无明显差别,而在治疗48 w时,初治组HBeAg/HBeAb血清转换率明显高于再治疗组（72.3%对63.1%,P<0.05）;在治疗48 w时,两组患者脂肪肝的改善率无明显差异（46.2%对50.0%,P>0.05）。结论核苷类药物与干扰素联合治疗慢性乙型肝炎合并脂肪肝患者疗效确切,在初治患者疗效更明显。     

Integrin alpha2beta1 plays a critical role in osteoblast response to micron-scale surface structure and surface energy of titanium substrates

Efforts to improve bone response to biomaterials have focused on ligands that bind α5β1 integrins. However, antibodies to α5β1 reduce osteoblast proliferation but do not affect differentiation when cells are grown on titanium (Ti). β1-silencing blocks the differentiation stimulus of Ti microtopography, suggesting that other β1 partners are important. Stably α2-silenced MG63 human osteoblast-like cells were used to test whether α2β1 specifically mediates osteoblast response to Ti surface micron-scale structure and energy. WT and α2-silenced MG63 cells were cultured on tissue culture polystyrene (TCPS) and Ti disks with different surface microtopographies: machined pretreatment (PT) surfaces [mean peak to valley roughness (R_a) < 0.02 μm], PT surfaces that were grit-blasted and acid-etched (SLA; R_a = 4 μm), and SLA with high surface energy (modSLA). Alkaline phosphatase (ALP), α2 and β1 mRNA, but not α5, αv, β3, type-I collagen, or osteocalcin, increased on SLA and modSLA at 6 days. α2 increased at 8 days on TCPS and PT, but remained unchanged on SLA and modSLA. α2-protein was reduced 70% in α2-siRNA cells, whereas α5-mRNA and protein were unaffected. α2-knockdown blocked surface-dependent increases in β1 and osteocalcin and decreases in cell number and increases in ALP and local factors typical of MG63 cells grown on SLA and modSLA [e.g., prostaglandin E₂, osteoprotegerin, latent and active TGF-β1, and stimulatory effects of 1α,25(OH)₂D₃ on these parameters]. This finding indicates that α2β1 signaling is required for osteoblastic differentiation caused by Ti microstructure and surface energy, suggesting that conclusions based on cell behavior on TCPS are not predictive of behavior on other substrates or the mechanisms involved.     

原发性胆汁性肝硬化患者肝组织转化生长因子β-1表达水平变化

目的 探讨原发性胆汁性肝硬化（PBC）患者肝组织转化生长因子-β1（TGF-β1）表达的变化。 方法 52例PBC患者接受超声引导下肝穿刺活检,选择病理科留取的正常肝组织20份作为对照,另选择20例健康人采集静脉血。采用免疫组化法检测肝组织TGFβ-1表达,采用ELISA法检测血清肿瘤坏死因子α（TNF-α）和白介素6（IL-6）水平。 结果 正常肝组织不表达或仅有少量TGF-β1表达,而PBC患者肝实质细胞胞浆内呈TGF-β1高表达;PBC患者血清TNF-α和IL-6水平分别为（28.71±13.54） pg/ml和（21.3±9.4） pg/ml,显著高于健康人【分别为（21.3±15.4） pg/ml和（2.1±1.6） pg/ml,P<0.01】;7例PBC肝组织肝纤维化S0期患者肝组织TGF-β1表达及血清TNF-α和IL-6水平分别为（0.5±0.2）10-2、（7.1±4.1） pg/ml和（5.1±1.0） pg/ml,显著低于12例S1期【（4.2±1.3） 10-2、（18.6±6.2） pg/ml、（11.5±3.6） pg/ml,P<0.01】、18例S2期【（6.9±1.2） 10-2、（27.3±9.9） pg/ml、（19.4±4.1） pg/ml,P<0.01】、9例S3期【（13.3±15.1） 10-2、（39.7±15.18） pg/ml、（27.3±8.1） pg/ml,P<0.01】和6例S4期【（21.2±17.1） 10-2、（53.4±17.3） pg/ml、（47.8±11.0） pg/ml,P<0.01】;15例Child-Pugh A级患者肝组织TGF-β1表达及血清TNF-α和IL-6水平分别为（1.9±1.6） 10-2、（12.2±3.1） pg/ml和（7.3±2.5） pg/ml,显著低于25例Child-Pugh B级【（15.9±13.6） 10-2、（32.9±8.6） pg/ml、（21.8±6.3） pg/ml,P<0.01】或12例C级患者【（22.6±18.5） 10-2、（49.1±19.3） pg/ml、（45.5±12.7） pg/ml,P<0.01】。 结论 PBC患者肝组织TGFβ-1表达及血清TNF-α和IL-6水平显著升高,可能与肝组织纤维化增生和/或肝功能受损有关。     

聚乙二醇干扰素α-2b治疗慢性乙型肝炎患者外周血T淋巴细胞亚群和血清细胞因子水平变化*

目的 研究聚乙二醇干扰素α-2b治疗慢性乙型肝炎患者外周血T淋巴细胞亚群和血清细胞因子水平的变化。 方法 2014年1月~2016年1月我院收治的184例慢性乙型肝炎患者,92例接受聚乙二醇干扰素α-2b联合恩替卡韦治疗48 w,另92例只接受恩替卡韦治疗。使用流式细胞仪检测外周血T淋巴细胞亚群,采用放射免疫法检测血清IL-6、INF-ɑ、IL-4,采用酶联免疫吸附法检测血清IL-17、TGF-β1和HBV标记物,采用荧光定量PCR法检测血清HBV DNA、核转录因子RORγt、Foxp3、IL-17mRNA。 结果 在停药随访24 w,联合组与恩替卡韦组血清HBV DNA阴转率分别为86.96%和84.78%（P>0.05）;联合组血清HBeAg阴转率为28.89%（13/45）,与恩替卡韦组的15.22%（7/46）比,无显著性差异（P>0.05）;联合组血清ALT水平为（34.6±11.6） U/L,显著低于恩替卡韦组【（64.6±20.5） U/L,P<0.05】;联合组外周血CD3+、CD4+细胞和CD4+/CD8+比值分别为（75.6±14.5）%、（42.7±10.3）%和（1.4±0.6）,显著高于恩替卡韦组【（66.8±14.4）%、（36.7±8.5）%和（1.0±0.5）,P<0.05】,CD8+细胞百分比为（29.3±7.3） %,显著低于恩替卡韦组【（34.8±8.5） %,P<0.05】,两组NK细胞百分比比较无显著性差异（P>0.05）;治疗前两组血清IL-6、IL-17、IL-4、INF-ɑ、TGF-β1水平比较无显著性差异（P>0.05）,治疗后联合组血清IL-6水平为（6.8±1.2）pg/ml,显著高于恩替卡韦组【（3.5±0.8） pg/ml,P<0.05】,IL-17水平为（0.7±0.3） pg/ml,显著低于恩替卡韦组【（2.8±0.9） pg/ml,P<0.05】,IL-4水平为（1.4±0.5）pg/ml,显著低于恩替卡韦组【（3.8±1.5）pg/ml,P<0.05】,INF-ɑ水平为（4.0±1.3） pg/ml,显著高于恩替卡韦组【（2.6±0.9）pg/ml,P<0.05】,两组血清TGF-β1水平比较无显著性差异（P>0.05）;治疗前两组血清Foxp3、IL-17和RORγt mRNA水平比较无显著性差异（P>0.05）,治疗后联合组血清RORγt水平为（0.86±0.31）,显著低于恩替卡韦组【（1.56±0.43）,P>0.05】,而两组血清Foxp3和IL-17mRNA水平比较无显著性差异（P>0.05）。 结论 聚乙二醇干扰素α-2b能通过调控细胞因子和核转录因子水平,从多个环节调控慢性乙型肝炎患者免疫功能,发挥抗病毒作用。     

聚乙二醇干扰素-α-2a治疗血清低水平HBsAg阳性的慢性乙型肝炎患者临床结局预测研究*

目的 分析聚乙二醇干扰素-α-2a (Peg-IFNα-2a)治疗低水平HBsAg阳性的慢性乙型肝炎（CHB）患者的临床结局及其血清HBsAg水平对疗效的预测价值。方法 2014年4月~2016年4月我院就诊的低水平HBsAg 阳性的CHB患者80例,采用随机数字表法将其分成两组,每组40例。患者入组前经核苷（酸）类似物（NAs）治疗获得病毒学应答。给予对照组恩替卡韦治疗,观察组接受恩替卡韦和Peg-IFNα-2a联合治疗48 w。采用受试者工作特征曲线（ROC）下面积（AUC）评估基线HBsAg水平预测HBsAg清除的效能。结果 在治疗48 w末,观察组血清HBsAg和HBV DNA水平分别为（1.5±0.3） lg U/ml和（0.1±0.1） lg U/ml,显著低于对照组的（2.0±0.2）lg U/ml和（1.3±0.3） lg U/ml（P<0.05）,观察组HBsAg清除率和HBV DNA转阴率分别为32.5%和92.5%,显著高于对照组的6.3%和55.0%（P<0.05）;基线HBsAg水平是HBsAg清除的独立相关因素（OR:0.337,95%CI:0.026~0.652, P<0.05）;经ROC曲线分析,以基线HBsAg水平等于2.0 lg U/mL为截断点,基线HBsAg水平预测治疗48 w血清HBsAg清除的AUC为0.77,敏感度为0.85,特异度为0.68,阳性预测值为67.2%,阴性预测值为85.3%,正确性为72.5%。结论 应用peg-IFN-α-2a治疗已经NAs治疗获得低水平HBsAg阳性的CHB患者可进一步提高临床疗效,且基线HBsAg水平能预测治疗结束时血清HBsAg清除情况。     

The essential role of insulin-like growth factor-1 in the intestinal tropic effects of glucagon-like peptide-2 in mice

BACKGROUND & AIMS: Glucagon-like peptide-2 (GLP-2) is an intestinal hormone that acts through unknown pathways to induce intestinal growth. We investigated the role of the insulin-like growth factors (IGF-1 and IGF-2) as mediators of GLP-2-enhanced growth in the murine intestine. METHODS: IGF-1 expression and secretion were determined in GLP-2-responsive primary intestinal cultures treated with GLP-2. Parameters of intestinal growth were assessed in wild-type (CD1, Igf1(+/+) and Igf2+), heterozygous (Igf1(+/-)), and null (Igf1(-/-) and Igf2(-P)) mice treated chronically with saline, GLP-2, IGF-1, or R-Spondin1. RESULTS: GLP-2 increased IGF-1 messenger RNA expression and IGF-1 secretion in intestinal cultures and increased expression of IGF-1 messenger RNA in mouse small intestine in vivo. Igf1(+/+) and Igf2+ mice responded to .1 microg/g(-1) per day(-1) GLP-2 with increased intestinal weights, morphometric parameters, and proliferative indices. In contrast, Igf1(-/-) mice were unresponsive to the same dose of GLP-2, failing to demonstrate changes in intestinal weight, morphometry, or proliferation. However, a significant effect of 1 microg/g(-1) per day(-1) GLP-2 was observed in Igf1(-/-) mice, but only in terms of small intestinal weight when normalized for body weight. Furthermore, Igf2(-P) mice demonstrated a partially impaired response in terms of small intestinal growth. Both Igf1(-/-) and Igf2(-P) mice exhibited normal-enhanced intestinal growth in response to IGF-1 and/or R-Spondin1. CONCLUSIONS: GLP-2 enhances intestinal IGF-1 expression and secretion, and IGF-1 is required for small and large intestinal growth in response to GLP-2. These findings identify IGF-1 as an essential mediator of the intestinotropic actions of GLP-2.     

INAUGURAL ARTICLE by a Recently Elected Academy Member:1H detection and dynamic nuclear polarization–enhanced NMR of Aβ1-42 fibrils

Several publications describing high-resolution structures of amyloid-β (Aβ) and other fibrils have demonstrated that magic-angle spinning (MAS) NMR spectroscopy is an ideal tool for studying amyloids at atomic resolution. Nonetheless, MAS NMR suffers from low sensitivity, requiring relatively large amounts of samples and extensive signal acquisition periods, which in turn limits the questions that can be addressed by atomic-level spectroscopic studies. Here, we show that these drawbacks are removed by utilizing two relatively recent additions to the repertoire of MAS NMR experiments—namely, ¹H detection and dynamic nuclear polarization (DNP). We show resolved and sensitive two-dimensional (2D) and three-dimensional (3D) correlations obtained on ¹³C,¹⁵N-enriched, and fully protonated samples of M₀Aβ_1-42 fibrils by high-field ¹H-detected NMR at 23.4 T and 18.8 T, and ¹³C-detected DNP MAS NMR at 18.8 T. These spectra enable nearly complete resonance assignment of the core of M₀Aβ_1-42 (K16-A42) using submilligram sample quantities, as well as the detection of numerous unambiguous internuclear proximities defining both the structure of the core and the arrangement of the different monomers. An estimate of the sensitivity of the two approaches indicates that the DNP experiments are currently ∼6.5 times more sensitive than ¹H detection. These results suggest that ¹H detection and DNP may be the spectroscopic approaches of choice for future studies of Aβ and other amyloid systems.

Amyloid fibrils are highly stable protein deposits found in β-sheet conformations and are notoriously recognized as disruptive agents to cellular function in over 40 human diseases (1, 2). Alzheimer’s disease (AD) is the most pervasive of all known plaque-related diseases and is associated with the presence of amyloid-β (Aβ) peptides in the extracellular space of the brain (3–6). As of 2021, there are ∼6.2 million people in the United States living with Alzheimer’s dementia and ∼50 million worldwide (7), and there is as of yet no cure available for AD. In order to address this epidemic, it is essential that we learn as much as possible about the formation and structure of Aβ plaques, including the detailed features of their catalytic surface, in order to design and develop appropriate treatments to limit the propagation of aggregates and the generation of toxic forms.Aβ is derived from the C-terminal region of the amyloid precursor protein (APP), a membrane protein in neuronal cells, via proteolysis by β- and γ-secretase (8, 9). One of the principal challenges in rationalizing AD etiology is Aβ’s diversity in peptide length, mutations, and posttranslational modifications (10). Their low solubility renders solution NMR ineffective, and high-resolution diffraction analyses have thus far been restricted to shorter peptides with all or most residues being ordered in the fibril core structure (11). Cryogenic electron microscopy (cryo-EM) has made strides in resolution in fibril studies within the past decade (12–18), but faces challenges studying with atomic-level detail due to polymorphism and heterogeneity in the fibril macroassemblies. Studying the individual and collective roles of amyloids at atomic resolution therefore requires alternative, high-resolution, high-throughput techniques for structural analysis. Magic-angle spinning NMR (MAS-NMR) was introduced as a technique with the potential to address these problems (19, 20). Recent technical advances (21, 22) and progress in sample preparation (23) have vastly improved the sensitivity and resolution of the spectra (24). Accordingly, there are now publications describing high-resolution structures of Aβ (25–29) and other amyloid (12, 16, 30–35) fibrils based on distance and torsion angle constraints derived from MAS experiments.To date, all of the known NMR structures of amyloid fibrils were determined using constraints obtained from ¹³C/¹⁵N MAS spectra, which are inhomogeneously broadened and therefore feature well-resolved lines at low spinning frequencies (<25 kHz) (36). However, resolution often remains insufficient for in-depth analysis, and the experiments require relatively large amounts of peptide and extensive signal acquisition periods. Two relatively recent additions to the repertoire of MAS NMR experiments—namely, ¹H detection and dynamic nuclear polarization (DNP)—promise to circumvent these issues by reducing signal acquisition times or, alternatively, the amount of protein required for the experiment (37). ¹H detection offers a factor of (γ_H/γ_S)^3/2 gain in sensitivity, where S is usually a low γ-spin (38–40) such as ¹³C or ¹⁵N. In these two cases it is possible to achieve a factor of ∼8 or ∼32 gain in sensitivity, respectively. Importantly, ¹H detection also introduces an additional spectral dimension and therefore significantly increases the resolution. In parallel, DNP offers a general approach to enhancing sensitivity by factors of ∼100, dramatically reducing signal acquisition times (by ∼10⁴). It does so by exploiting the high spin polarization of unpaired electrons (of gyromagnetic ratio γ_e ∼660 times larger than γ_H) of a paramagnetic polarizing agent to enhance sensitivity by a theoretical factor of γ_e/γ_H. (41–44) Furthermore, DNP experiments are conducted at ∼100 K, thereby increasing the Boltzmann polarization and sensitivity by another factor of ∼3 over experiments conducted at ambient temperature (45).While these arguments are well established for MAS NMR in many systems, it is less obvious that they are applicable to amyloid samples because spectra of amyloids are known to be broad for a variety of reasons, such as sample purity and polymorphism. Furthermore, ¹H-detected NMR at moderate MAS frequencies (∼20 to 60 kHz) needs to be coupled to different levels of deuteration to ensure high sensitivity and narrow linewidths (42). Accordingly, deuteration with partial reprotonation of the amide or Hα sites has been implemented in pioneering studies on Aβ_1-40 at 20 kHz MAS (46), HET-s(218–289) (47), and D76N-β2m at 60 kHz MAS (48). In addition, selective protonation in Aβ_1-40 fibril methyl groups at 18 kHz MAS has led to highly resolved ¹H-detected ¹³C correlations (49). In deuterated samples, however, the amount of potentially available structural information is significantly reduced, which can impair high-resolution structure determinations. The advent of 0.7 mm MAS rotors that achieve ω_r/2π >110 kHz attenuates ¹H-¹H dipole couplings and allows direct acquisition of multidimensional ¹H data without requiring deuteration (50). Furthermore, the spectra provide assignments and structural information. While a proof-of-concept application of this approach was demonstrated on fully protonated highly regular prion fibrils (51, 52), it is not clear whether this methodology is generally applicable and extendable to the detection of resolved inter- and intramolecular contacts in complex amyloid assemblies.In parallel, our MAS DNP studies on M₀Aβ_1-42 (28, 32, 53) report significant broadening of the NMR lines at cryogenic temperatures, which was attributed to distributions of conformations trapped at low temperature and is therefore inhomogeneous in origin. The loss of resolution associated with the MAS DNP methodology is a major obstacle for the detailed structural study of uniformly labeled amyloid samples. Concurrently, reports of well-resolved spectra at high fields and spinning frequencies suggest that the broadening is homogeneous (54–56). The advent of DNP instrumentation operating at high magnetic fields (18.8 T) and faster MAS (ω_r/2π = 40 kHz) provides an approach to alleviate this limitation by attenuating homogeneous couplings (57). However, this comes at the expense of the enhancement factor, potentially compromising the capacity to carry out expeditious multidimensional and multinuclear correlations. Moreover, NMR spectra of amyloid fibrils are known to suffer from additional debilitating broadening associated with their heterogeneous character (sample purity, polymorphism, etc.), which may mitigate the benefits of high magnetic fields.In this work, we show that high resolution and sensitivity are possible for fibrils of M₀-Aβ_1-42. Notably, we demonstrate rapid resonance assignment and site-resolved detection of numerous site-specific internuclear proximities on submilligram sample quantities via ¹H-detected NMR at ω_r/2π ∼110 kHz and high field (23.4 T/1,000 MHz for ¹H) at room temperature and ¹³C-detected DNP MAS NMR at ω_r/2π = 40 kHz and high field (18.8 T/800 MHz for ¹H) at low temperature. While both ¹H detection and DNP afford increased sensitivity, we estimate, using approaches outlined by Ishii and Tycko (40), that DNP, with our current ε = 22, yields a factor of ∼6.5 higher sensitivity. These results therefore illuminate possible paths for the rapid structure elucidation of amyloid fibrils available in limited quantities.     

恩替卡韦联合聚乙二醇干扰素或胸腺素治疗代偿期乙型肝炎肝硬化2年疗效随访*

目的 探讨应用恩替卡韦联合聚乙二醇干扰素α-2a（PEG-IFNα-2a）或胸腺素治疗代偿期乙型肝炎肝硬化患者的效果。方法 在88例代偿期乙型肝炎肝硬化患者中,接受恩替卡韦治疗者38例,接受恩替卡韦联合PEG-IFNα-2a治疗者17例,联合胸腺素治疗者33例,随访2年。结果 恩替卡韦治疗组治疗前和治疗104 w末血清HBV DNA水平分别为（5.6±1.7） IU/ml和（1.0±0.7） IU/ml（P<0.05）,联合PEG-IFNα-2a组分别为（5.8±1.3） IU/ml和（1.0±0.7） IU/ml（P<0.05）,联合胸腺素组分别为（6.1±2.0） IU/ml和（1.0±0.9） IU/ml（P<0.05）;恩替卡韦组治疗前和治疗104 w末血清ALB水平分别为（43.1±5.4） g/L和（46.9±4.9） g/L（P<0.05）,联合胸腺素组分别为（43.0±4.0） g/L和（46.8±5.4） g/L（P<0.05）;三组治疗前和治疗104 w末肝脏硬度值和INR无统计学差异（P>0.05）。结论 恩替卡韦能有效抑制HBV DNA复制,维持代偿期肝硬化患者的肝功能,本研究结果看不出联合用药有任何好处,需要进一步观察。     

Comparative study of mutations in SNP loci of K-RAS,hMLH1 and hMSH2 genes in neoplastic intestinal polyps and colorectal cancer

AIM: To clarify the molecular mechanism involved in pathogenesis of colorectal cancer as well as clinical significance of genetic analysis of histological samples.METHODS: A total of 480 blood and tissue specimens were collected in our hospital from January 2011 to October 2012. In the observation group, there were 120 blood specimens and 120 intestinal tract tissue specimens collected from patients with neoplastic intestinal polyps. In the control group I there were 80 blood specimens and 80 intestinal tract tissue specimens collected from patients with colorectal cancer. In the control group II there were 40 blood specimens and 40 intestinal tract tissue specimens collected from healthy individuals. The gene segments were amplified using PCR and DNA gel electrophoresis along with DNA sequence analysis were employed for the detection of the following single nucleotide polymorphisms (SNPs): K-RAS codons 12 and 13; hMLH1 (human mutS homolog 1) gene missense mutation at Va1384Asp; hMSH2 (human mutS homolog 2) gene missense mutation at 2783C/A.RESULTS: The mutation rate of the SNP at Va1384Asp locus of the hMLH1 gene from blood and tissue specimens in the observation group showed no statistical difference from those in the control group I. The mutation rates of SNPs in codons 12 and 13 of K-RAS and at 2783C/A locus of the hMSH2 gene were significantly lower in the observation group than in the control group I (χ² = 15.476, 29.670, 10.811, 16.618, 33.538, 7.898, P < 0.05). The mutation rate of SNP at Va1384Asp locus of the hMLH1 gene was significantly higher in the observation group when compared to the control group II (χ² = 10.486, 4.876, P < 0.05). The mutation rates of SNPs in codons 12 and 13 of K-RAS and at 2783C/A locus of the hMSH2 gene did not show any statistical difference from those in the control group II.CONCLUSION: There may be important clinical significance and relevance between neoplastic intestinal polyps and colorectal cancer in terms of the mechanisms involved in the pathogenesis.     

Prolonged and enhanced secretion of glucagon-like peptide 1 (7-36 amide) after oral sucrose due to α-glucosidase inhibition (acarbose) in Type 2 diabetic patients

GLP-1, an incretin hormone of the enteroinsular axis with insulinotropic and glucagonostatic activity, is secreted after nutrient ingestion. GLP-1 is mainly produced by intestinal L-cells in the lower gastrointestinal tract (GIT); simple carbohydrates are absorbed in the upper GIT and α-glucosidase inhibition leads to augmented and prolonged GLP-1 release in normal subjects. In a cross-over study, 100 mg acarbose or placebo was administered simultaneously with 100 g sucrose to 11 hyperglycaemic Type 2 diabetic patients poorly controlled with diet and sulphonylureas. Plasma levels of GLP-1, insulin, C-peptide, glugacon, GIP, glucose and H₂-exhalation were measured over 6 h. Differences in the integrated responses over the observation period were evaluated by repeated measurement analysis of variance with fasting values used as covariates. With acarbose, sucrose reached the colon 60–90 min after ingestion as indicated by a significant increment in breath hydrogen exhalation (p = 0.005). After an early GLP-1 increment 15 min after sucrose under both conditions, GLP-1 release was prolonged in the acarbose group (p = 0.001; significant from 210 to 360 min). Initially (0–150 min), glucose (p = 0.001), insulin (p = 0.001), and GIP (p<0.001) were suppressed by acarbose, whereas later there were no significant differences. Glucagon levels were higher with acarbose in the last 3 h of the 6 h observation period (p = 0.02). We conclude that in hyperglycaemic Type 2 diabetic patients, ingestion of acarbose with a sucrose load leads to elevated and prolonged GLP-1 release. © 1998 John Wiley & Sons, Ltd.     

Neuropeptide Y impairs insulin-stimulated translocation of glucose transporter 4 in 3T3-L1 adipocytes through the Y1 receptor

Neuropeptide Y (NPY) is expressed in adipose tissue and is involved in adipocyte metabolism. Although NPY impacts on glucose utilization in vivo, the underlying cellular mechanism is yet to be fully elucidated.In this study we investigated the effect of NPY on the insulin-stimulated translocation of glucose transporter 4 (GLUT4) from intracellular stores to the cell surface in vitro. Using cellular fractionation and immunofluorescence we analyzed the cellular localization and content of GLUT4 in 3T3-L1 adipocytes. Additionally we investigated the effect of NPY on insulin action in adipocyte cultures by assessing the phosphorylation of Akt and [³H]-deoxyglucose uptake.Our data suggest that in 3T3-L1 adipocytes NPY inhibits insulin-stimulated glucose uptake in a GLUT4-dependent manner. The insulin induced translocation of GLUT4 was attenuated by the Y1 receptor agonist [Phe(7),Pro(34)] pNPY, demonstrating an essential role of the Y1 receptor in GLUT4 translocation. Additionally, we observed an NPY dose-dependent impairment of Akt phosphorylation.This study provides evidence that NPY impairs the insulin sensitivity of adipocytes and suggests that the Y1 receptor could be a potential therapeutic target for type 2 diabetes.