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Updated: Jun 7, 2026
Megakaryocyte Differentiation and Platelet Formation from Human Cord Blood-derived CD34+ Cells
Published on: December 27, 2017
Human CD34+/KDR+ cells are generated from circulating CD34+ cells after immobilization on activated platelets
H C de Boer1, M M Hovens, A M van Oeveren-Rietdijk
1Department of Nephrology, Leiden University Medical Center, Albinusdreef 2, Leiden, the Netherlands.
Objective:
The presence of kinase-insert domain-containing receptor (KDR) on circulating CD34+ cells is assumed to be indicative for the potential of these cells to support vascular maintenance and repair. However, in bone marrow and in granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood, less than 0.5% of CD34+ cells co-express KDR. Therefore, we studied whether CD34+/KDR+ cells are generated in the peripheral circulation.
Methods And Results:
Using an ex vivo flow model, we show that activated platelets enable CD34+ cells to home to sites of vascular injury and that upon immobilization, KDR is translocated from an endosomal compartment to the cell-surface within 15 minutes. In patients with diabetes mellitus type 2, the percentage of circulating CD34+ co-expressing KDR was significantly elevated compared to age-matched controls. When treated with aspirin, the patients showed a 49% reduction in the generation of CD34+/KDR+ cells, indicating that the level of circulating CD34+/KDR+ cells also relates to in vivo platelet activation.
Conclusions:
Circulating CD34+/KDR+ are not mobilized from bone marrow as a predestined endothelial progenitor cell population but are mostly generated from circulating multipotent CD34+ cells at sites of vascular injury. Therefore, the number of circulating CD34+/KDR+ cells may serve as a marker for vascular injury.
