Human adipose tissue contains erythroid progenitors expressing fetal hemoglobin

Core Tip

Core tip: Stromal vascular fraction (SVF) from human adipose tissue contains mesodermal precursors with the ability to form mixed hematoendothelial colonies and hematopoietic colony-forming units, though this occurs at an extremely low frequency. It is well known that hematopoietic progenitors residing in the bone marrow are released into the circulation and enter peripheral tissues; therefore, the most plausible explanation for this hematopoietic activity is that these cells are actually circulating hematopoietic progenitors. However, it is also possible that they may originate from the adipose tissue itself. To address this hypothesis, we compared the expression levels of the most relevant hematopoietic transcription factors in cells isolated from SVF with their expression levels in CD34⁺ cells isolated from adult peripheral blood and cord blood. Moreover, because the composition of hemoglobin in erythroid cells varies depending on the origin of the hematopoietic progenitors and their ontogenic stage, burst-forming units-erythroid were developed in culture, and the hemoglobin composition and globin gene expression in erythroid colonies were determined. Our results provide evidence that erythroid progenitors contained in SVF exhibit features that differ from those of circulating progenitors. These findings should encourage further research on stem cells and the microenvironment of human adipose tissue.