A closer look at adipose tissue lymphatics and their markers.

Purpose Of Review: Lymphatic vessels are found in most tissues, with the exception of the cornea and the central nervous system. Tissues that have high exposure to antigens, such as the skin and the intestine, have especially extensive lymphatic vascular networks. Despite being densely vascularized with blood vessels, adipose tissue is poorly permeated with lymphatic vasculature. Here, we focus on the recent advances in the research on adipose tissue lymphatics and present a lymphatic-focused analysis of published single-cell and single-nucleus RNA sequencing datasets of adipose tissues.

Recent Findings: Although lymphatic expansion in obesity may limit inflammation and promote glycerol efflux from adipose tissue, lymphatic endothelial cells (LECs) secrete factors that reduce brown adipocyte thermogenesis. Transcriptomic analyses of these cells show that they express common lymphatic markers such as Proxl, but datasets from different studies show great variation in gene expression values due to the low number of captured LECs, depot differences, and species-specific gene expression patterns.

Summary: As the importance of LECs in the homeostasis of adipose tissue has become evident, investigators want to shed light on the specific interactions of lymphatics with other cell types in adipose tissues. Extracting LECs from readily available transcriptomics datasets provides a standpoint for investigators for future research. However, systematic studies are needed to reveal unique identities according to depot and species-specific LEC signatures.