SSAT：血管生成与小儿克罗恩病相关

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　　5月18日，在即将召开的2013美国消化疾病周上，来自美国俄亥俄州辛辛那提儿童医院医疗中心的研究者珍妮弗将发表题为《小儿克罗恩病血管内皮生长因子表达，血管生成和炎症关系》的演讲。早发型克罗恩病（CD）占克罗恩病的25％，但是有别于成人型CD，其疾病活动指数更严重，免疫抑制剂要求增加，肠道参与更广泛。慢性炎性疾病和血管生成之间的致病关系，促使研究其在炎性肠病中的作用。研究者推测血管内皮生长因子（VEGF）在克罗恩病炎症中发挥了重要作用，促进血管生成。研究指出，切除的回肠标本微血管密度增加与更多炎症相关，通过对此观察，血管生成与小儿克罗恩病相关。在分子水平上，证明血管内皮生长因子转录和蛋白质水平升高，暗示早发型克罗恩病血管生成VEGF通路与炎症相关。进一步调查关于血管生成的机制，它与炎症的关系和抗血管生成疗法的有效性是必要的。

　　儿科患者组（n＝13），年龄12至16岁，在研究者所在机构为CD患者进行末端回肠切除术，与非炎性切除术适应证的对照组（n＝5）患者相比较。此外，比较炎性和非炎性回肠组每个克罗恩病的病理标本。样品炎症评估通过克罗恩病组织学严重指数（Crohn's Histology Index of Severity）（范围0～13），微血管密度评估通过内皮细胞CD31免疫组化定量。类似组织VEGF-A mRNA和蛋白质表达分别通过RT-PCR和蛋白质印记进行评估。平均值±SEM结果表达通过方差分析和学生t检验分析（P＜0.05）有显著性。

　　炎性CD组与对照组之间（5.8±0.7 对 0.62±0.38，P＜0.001），配对炎症和非炎症回肠之间（5.8±0.7 对 1.2±0.6，P＜0.001），炎症分数明显增加（图1）。与对照组相比，炎症和非炎症CD组微血管密度增加（炎性组 24955±3202 µm2，非炎性组 18719±2050 µm2，对照组9032±1474 µm2）,有显著性差异（P＝0.008），只出现在炎症CD组和对照组之间（图2）。CD患者VEGF-A mRNA表达组织上调（CD 8.5±2.51 对2.32±0.58，P＝0.034），并与VEGF-A蛋白质水平增加的趋势相关（VEGF/GAPDH，CD 3.96 对 对照组 2.20，P＝0.53）。

与克罗恩相关的拓展阅读：

• NEJM：发现治疗克罗恩氏病的潜在新药物疗法
• PLoS ONE：揭示克罗恩氏病患者肠道组织纤维化的分子机制
• PLoS One：了解克罗恩病的纤维化
• AJHG：超过200个克罗恩病基因被识别
• 儿科克罗恩病患者行MR肠造影可行 更多信息请点击：有关克罗恩更多资讯

Link Between VEGF Expression, Angiogenesis and Inflammation in Pediatric Crohn's Disease
Purpose
Early-onset Crohn's disease (CD) accounts for 25% of cases but is distinct from adult-onset CD by a more severe disease activity index, increased immunosuppressant requirement, and more extensive intestinal involvement. The pathogenic link between chronic inflammatory diseases and angiogenesis prompted investigations into its role in inflammatory bowel disease. We hypothesize that VEGF driven angiogenesis plays a significant role in Crohn's disease inflammation.
Methods
Pediatric patients (n=13), ages 12 to 16, at our institution having undergone resection involving the terminal ileum for CD were compared to controls (n=5) with non-inflammatory indications for resection. Additionally, from each Crohn's pathology specimen, inflamed and non-inflamed ileum were obtained for comparison. Samples were evaluated for inflammation using the Crohn's Histology Index of Severity (range 0-13) and for microvessel density by quantitative endothelial cell immunohistochemistry using CD31. Corresponding tissues were assessed for VEGF-A mRNA and protein expression by RT-PCR and Western blot respectively. Results expressed as mean±SEM were analyzed for significance (P?0.05) by ANOVA and Student's t-test.
Results
Inflammation scores were significantly increased (Fig 1) between inflamed CD and controls (5.8±0.7 vs 0.62±0.38, P<0.001), and between paired inflamed and non-inflamed ileum (5.8±0.7 vs 1.2±0.6, P< 0.001). Increased microvessel density was observed in both inflamed and non-inflamed CD groups compared to controls (inflamed 24,955±3,202µm2, non-inflamed 18,719±2,050µm2, control 9,032±1,474µm2), with statistical significance (P=0.008) only present between inflamed CD and control subjects (Fig 2). Expression of tissue VEGF-A mRNA was upregulated in CD (CD 8.5±2.51 vs control 2.32±0.58, P=0.034), and was associated with an increased trend in VEGF-A protein levels (VEGF/GAPDH, CD 3.96 vs control 2.20, P=0.53).
Conclusion
Angiogenesis is associated with pediatric Crohn's disease as observed by increased microvessel density that correlates with greater inflammation in resected ileal specimens. At the molecular level, we demonstrate elevated VEGF transcription and protein levels, which implicates a VEGF pathway for angiogenesis associated inflammation in early-onset Crohn's disease. Further investigations regarding mechanism of angiogenesis, its relationship to inflammation, and effectiveness of anti-angiogenic therapies are warranted.