The identity of the peritubular population of cells with mesenchymal phenotype thought
responsible for producing erythropoietin in humans remains unclear. Here, renal
CD133+/CD73+ progenitor cells, isolated from the human renal inner medulla and
described as a population of mesenchymal progenitors, released erythropoietin under
hypoxic conditions. CD133− cells did not synthesize erythropoietin, and CD133+ progenitor
cells stopped producing erythropoietin when they differentiated and acquired an epithelial …