Characterization of Human Adipose Tissue-Resident Hematopoietic Cell Populations Reveals a Novel Macrophage Subpopulation with CD34 Expression and Mesenchymal Multipotency

Abstract

Adipose tissue (AT) is composed of mature adipocytes and stromal vascular fraction (SVF) cells, including adipose stem/stromal cells (ASCs). We characterized hematopoietic cells residing in human nonobese AT by analyzing the SVF isolated from human lipoaspirates and peripheral blood (PB /CD206+ ATMs could grow in adherent culture and were capable of differentiating into multiple mesenchymal (adipogenic, osteogenic, and chondrogenic) lineages, similar to ASCs. CD34 + /CD206+ ATMs grew rapidly and lost expression of CD45, CD14, and CD206 by passage 3, which resulted in a similar expression profile to ASCs. Thus, this novel ATM subpopulation (CD45+ ) showed distinct biological properties from other ATMs and circulating monocytes/macrophages. The CD34 + /CD206+ ATMs possessed characteristics similar to ASCs, including adherence, localization, morphology, and mesenchymal multipotency. This AT-resident subpopulation may have migrated from the bone marrow and may be important to tissue maintenance and remolding.

Generation of a functional liver tissue mimic using adipose stromal vascular fraction cell-derived vasculatures

“…Within the SVF are these support cells, such as perivascular cells and/or mesenchymal stem cells. But, also other stromal cells present in the isolate, such as fibroblasts and macrophages, may be important1242. Although it is possible that vascular beds from all tissues22, when isolated and disassembled, would show the same self-assembly capacity as demonstrated here by adipose-derived SVF cells, the adipose vasculature has been proposed to be evolutionarily less mature than other more quiescent vascular beds and thus more plastic43.…”

Adipose-derived mesenchymal stromal/stem cells: An update on their phenotype in vivo and in vitro

“…Beside the assumed ASCs (CD34 + /CD31 -/CD146 -), they identified endothelial cells (CD34 + /CD31 + /CD146 -), haematopoietic stem-like cells (CD34 + /CD45 + ) and vascular smooth muscle cells/pericytes (CD34 + /CD31 -/CD146 + ) [57] . An adipose tissue resident macrophage population expressing CD34 (and co-expressing the macrophage marker CD206) within the SVF has also been described [58] . Furthermore, several haematopoietic CD34 + subpopulations (co-expressing CD45) were also described, but these were eliminated by the following plastic adhesion.…”

The CD45+ fraction in murine adipose tissue derived stromal cells harbors immune‐inhibitory inflammatory cells

“…Thus, inhibitory inflammatory cells, specifically those similar to M2‐type MΦs, are present among CD45 + u‐ADSCs from enzymatically digested adipose tissue. A previous phenotypic analysis of human adipose tissue derived stromal cells showed that hematopoietic stem cells harbored M2‐like anti‐inflammatory cells, and were likely derived from myeloid tissue . We functionally identified inhibitory inflammatory cells among leukocyte‐related antigen‐expressing u‐ADSCs.…”