Fig. 1

Two different types of EPC. Early EPCs Originating from bone marrow or hematopoietic progenitor cells, spindle shaped. Cultivation period: 4–7 days. Markers: CD14⁺/CD115⁺ (monocyte/macrophage characteristics), CD31/CD34/CD133/VEGFR-2/CD45⁺ (dual markers of endothelium and hematopoiesis). Function: Intake of Acetylated low-density lipoprotein and binding to UEA-1; Secreted high levels of VEGF/IL-8; Promotes angiogenesis but weak proliferative ability, making it difficult to propagate. Potential role: vascular repair and inflammation regulation. Late EPCs Source and morphology: Derived from bone marrow CD34 ⁺ hematopoietic stem cells, with a pebble like morphology. Cultivation period: 14–21 days. Markers: CD14 ⁻/CD115 ⁻, high expression of KDR/CXCR-1; Low hematopoietic related markers (WAS/LYN). Function: Strong proliferative ability, capable of forming capillary like structures; The in vitro angiogenic activity is comparable to eEPC. Characteristics: It is closer to mature endothelial cells and exhibits microvascular endothelial behavior