Yang Hua, Sun Xiaoyi, Haxhija Emir Q, Teitelbaum Daniel H
Section of Pediatric Surgery, Department of Surgery, the University of Michigan Medical School and the C S Mott Children's Hospital, Ann Arbor, Michigan, USA.
Am J Physiol Gastrointest Liver Physiol. 2007 Jan;292(1):G84-91. doi: 10.1152/ajpgi.00192.2006.
Total parenteral nutrition (TPN), with the absence of enteral nutrition, results in profound changes to both intestinal epithelial cells (EC) as well as the adjacent intraepithelial lymphocyte (IEL) population. Intestinal EC are a rich source of IL-7, a critical factor to support the maintenance of several lymphoid tissues, and TPN results in marked EC changes. On this basis, we hypothesized that TPN would diminish EC-derived IL-7 expression and that this would contribute to the observed changes in the IEL population. Mice received enteral food and intravenous crystalloid solution (control group) or TPN. TPN administration significantly decreased EC-derived IL-7 expression, along with significant changes in IEL phenotype; decreased IEL proliferation; and resulted in a marked decrease in IEL numbers. To better determine the relevance of TPN-related changes in IL-7, TPN mice supplemented with exogenous IL-7 or mice allowed ad libitum feeding and treated with exogenous administration of anti-IL-7 receptor (IL-7R) antibody were also studied. Exogenous IL-7 administration in TPN mice significantly attenuated TPN-associated IEL changes, whereas blocking IL-7R in normal mice resulted in several similar changes in IEL to those observed with TPN. These findings suggest that a decrease in EC-derived IL-7 expression may be a contributing mechanism to account for the observed TPN-associated IEL changes.
全肠外营养（TPN），在缺乏肠内营养的情况下，会导致肠上皮细胞（EC）以及相邻的上皮内淋巴细胞（IEL）群体发生深刻变化。肠EC是白细胞介素-7（IL-7）的丰富来源，IL-7是支持多种淋巴组织维持的关键因子，而TPN会导致明显的EC变化。在此基础上，我们假设TPN会减少EC衍生的IL-7表达，并且这将导致观察到的IEL群体变化。小鼠接受肠内食物和静脉晶体溶液（对照组）或TPN。给予TPN显著降低了EC衍生的IL-7表达，同时IEL表型也发生了显著变化；IEL增殖减少；并导致IEL数量显著减少。为了更好地确定TPN相关的IL-7变化的相关性，还研究了补充外源性IL-7的TPN小鼠或随意进食并接受外源性抗IL-7受体（IL-7R）抗体治疗的小鼠。在TPN小鼠中给予外源性IL-7显著减轻了与TPN相关的IEL变化，而在正常小鼠中阻断IL-7R导致IEL出现了一些与TPN观察到的相似变化。这些发现表明，EC衍生的IL-7表达降低可能是导致观察到的与TPN相关的IEL变化的一个促成机制。
