DiGuilio Katherine M, Mercogliano Christina M, Born Jillian, Ferraro Brendan, To Julie, Mixson Brittany, Smith Allison, Valenzano Mary Carmen, Mullin James M
Katherine M DiGuilio, Christina M Mercogliano, Brittany Mixson, Allison Smith, Mary Carmen Valenzano, James M Mullin, Lankenau Institute for Medical Research, Lankenau Medical Center, Wynnewood, PA 19096, United States.
World J Gastrointest Pathophysiol. 2016 May 15;7(2):223-34. doi: 10.4291/wjgp.v7.i2.223.
To study whether the inflammatory bowel disease (IBD) colon which exhibits varying severity and cytokine levels across its mucosa create varying types of transepithelial leak.
We examined the effects of tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1-β (IL1β) and hydrogen peroxide (H2O2) - singly and in combinations - on barrier function of CACO-2 cell layers. Our focus was on the type (not simply the magnitude) of transepithelial leak generated by these agents as measured by transepithelial electrical resistance (TER) and transepithelial flux of (14)C-D-mannitol, (3)H-Lactulose and (14)C-Polyethylene glycol as radiolabeled probe molecules. The isoquinoline alkaloid, berberine, was then examined for its ability to reduce specific types of transepithelial leak.
Exposure to TNF-α alone (200 ng/mL; 48 h) induced a 50% decrease in TER, i.e., increased leak of Na(+) and Cl(-) - with only a marginal but statistically significant increase in transepithelial leak of (14)C-mannitol (Jm). Exposure to TNF-α + IFN-γ (200 ng/mL; 48 h) + IL1β (50 ng/mL; 48 h) did not increase the TER change (from TNF-α alone), but there was now a 100% increase in Jm. There however was no increase in transepithelial leak of two larger probe molecules, (3)H-lactulose and (14)C-polyethylene glycol (PEG). However, exposure to TNF-α + IFN-γ + IL1β followed by a 5 h exposure to 2 mmol/L H2O2 resulted in a 500% increase in (14)C-PEG leak as well as leak to the luminal mitogen, epidermal growth factor.
This model of graded transepithelial leak is useful in evaluating therapeutic agents reducing IBD morbidity by reducing barrier leak to various luminal substances.
研究炎症性肠病（IBD）结肠黏膜炎症严重程度和细胞因子水平各异时，是否会产生不同类型的经上皮渗漏。
我们研究了肿瘤坏死因子-α（TNF-α）、干扰素-γ（IFN-γ）、白细胞介素-1-β（IL1β）和过氧化氢（H2O2）单独及联合作用对Caco-2细胞层屏障功能的影响。我们关注的是这些试剂所产生的经上皮渗漏的类型（而非仅仅是程度），通过跨上皮电阻（TER）以及作为放射性标记探针分子的（14）C-D-甘露醇、（3）H-乳果糖和（14）C-聚乙二醇的跨上皮通量来测量。随后研究了异喹啉生物碱黄连素减少特定类型经上皮渗漏的能力。
单独暴露于TNF-α（200 ng/mL；48小时）会导致TER降低50%，即Na(+)和Cl(-)的渗漏增加，而（14）C-甘露醇的跨上皮渗漏（Jm）仅有轻微但具有统计学意义的增加。暴露于TNF-α + IFN-γ（200 ng/mL；48小时）+ IL1β（50 ng/mL；48小时）并未增加TER的变化（相对于单独使用TNF-α），但此时Jm增加了10%。然而，两种较大的探针分子（3）H-乳果糖和（14）C-聚乙二醇的跨上皮渗漏并未增加。但是，暴露于TNF-α + IFN-γ + IL1β后再暴露于2 mmol/L H2O2 5小时，会导致（14）C-聚乙二醇渗漏增加500%，以及向腔内有丝分裂原表皮生长因子的渗漏增加。
这种分级经上皮渗漏模型有助于评估通过减少对各种腔内物质的屏障渗漏来降低IBD发病率的治疗药物。
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