Intravital imaging of intestinal lacteals unveils lipid drainage through contractility
Intravital imaging of intestinal lacteals unveils lipid drainage through contractility
复制标题
DOI：
10.1172/jci76509
复制
发表时间：
2015-11-01
影响因子：
15.9
通讯作者：
Kim, Pilhan
中科院分区：
文献类型：
--
作者：
Choe, Kibaek;Jang, Jeon Yeob;Kim, Pilhan
乳糜管是位于每个肠绒毛中心的淋巴管，为脂质和其他亲脂性分子提供必要的转运途径。然而，目前还不清楚吸收的分子如何通过乳管运输。在这里，我们使用的报告小鼠，表达GFP的控制下的荧光特异性启动子Prox1和定制的共聚焦显微镜，并进行活体实时可视化的吸收和运输动力学的荧光标记的脂肪酸（FA）和各种外源性分子在体内肠绒毛。这些分析清楚地揭示了这些分子通过肠上皮细胞的跨上皮吸收，在固有层上的扩散分布，以及随后通过乳汁的运输。此外，我们观察到乳糜管的主动收缩，这似乎直接参与膳食脂质排出。我们的分析表明，围绕每个乳管的平滑肌负责收缩动力学，乳管收缩最终由自主神经系统控制。这些结果表明，乳管是一个独特的器官特异性淋巴系统，不仅作为一个被动的管道，但作为一个主动泵，运输脂质。总的来说，使用这种有效的成像方法，我们发现了小肠绒毛中吸收的分子的排出和参与的乳汁收缩性。
Lacteals are lymphatic vessels located at the center of each intestinal villus and provide essential transport routes for lipids and other lipophilic molecules. However, it is unclear how absorbed molecules are transported through the lacteal. Here, we used reporter mice that express GFP under the control of the lymphatic-specific promoter Prox1 and a custom-built confocal microscope and performed intravital real-time visualization of the absorption and transport dynamics of fluorescence-tagged fatty acids (FAs) and various exogenous molecules in the intestinal villi in vivo. These analyses clearly revealed transepithelial absorption of these molecules via enterocytes, diffusive distribution over the lamina propria, and subsequent transport through lacteals. Moreover, we observed active contraction of lacteals, which seemed to be directly involved in dietary lipid drainage. Our analysis revealed that the smooth muscles that surround each lacteal are responsible for contractile dynamics and that lacteal contraction is ultimately controlled by the autonomic nervous system. These results indicate that the lacteal is a unique organ-specific lymphatic system and does not merely serve as a passive conduit but as an active pump that transports lipids. Collectively, using this efficient imaging method, we uncovered drainage of absorbed molecules in small intestinal villus lacteals and the involvement of lacteal contractibility.