Table 1.
Characteristic data of type H, L and E endothelial cells
| Characteristics | Type H | Type L | Type E | References |
|---|---|---|---|---|
| Marker expression | CD31hiEMCNhi | CD31loEMCNlo | CD31hiEMCNlo | 39,40 |
| Location | Endosteum and metaphysis | Diaphysis | Endosteum and compact bone | 40 |
| Morphology | Linearly structured, columnarly arranged vessels | Reticularly branched network | Linearly structured, columnarly arranged vessels | 21,41 |
| Surrounding cells | Osterix-expressing osteoprogenitor cells; PDGFR-β and NG2-expressing perivascular cells | Haematopoietic cells; CAR cells; PDGFR-a and LEPR-expressing perivascular cells | Osterix-expressing osteoprogenitor cells | 8,42–44 |
| Function | Mediate bone formation | Mediate haematopoietic process | Maintain bone formation | 8,39,42 |
| Blood celocity | High | Low | / | 18,48 |
| Oxygenation | Well oxygenated | Hypoxic | / | 18,48 |
| Permeability | Low | High | / | 18,48 |
| Relationship with aging | Reduction | No significant change | Rapid reduction during postnatal stages | 39 |
| Interconversion between different ECs | Type H→Type L; Type H→Arterial ECs | Type H→Type L | Type E→Type H; Type E→Arterial ECs | 16,39 |
EC endothelial cell, CD31 also known as PECAM-1, platelet endothelial cell adhesion molecule, EMCN endomucin, PDGFR platelet-derived growth factor receptor, NG2 neuron-glial antigen 2, CAR cells cytokines chemokine ligand 12 (CXCL12)-abundant reticular cells, LEPR leptin receptor