Dietary lipids accumulate in macrophages and stromal cells and change the microarchitecture of the mesenteric lymph node I

Obesity has emerged as a worldwide problem in human health. Dietary lipids are taken up and transported via lymphatics into the circulatory system. During this process, lipids pass the mesenteric lymph node (mLN). These organs filter the lymph fluid for foreign antigens to induce and control immune responses. Alteration of that function during obesity has only slightly been studied. Here, we characterize changes within the microarchitecture of the mLN during high levels of lipid transport and highlight the role of stromal cells. Microarray experiments detected gene probes expressed by mLN stromal cells. Transmission electron microscopy enabled us to identify lipid droplets in different stromal cells, and in macrophages. Sizes, numbers and intercellular distances increased after 10 weeks of a high-fat diet. Thus, we propose that changes in the microarchitecture and increased accumulation of lipid droplets in stromal cells and macrophages have an influence on the immunological function of the mLN. In two independent approaches, CD45- stem cells from pLN or mLN were sorted, total RNA was prepared and subjected to single color microarray analysis (4 hybridizations in total).