A comparison of endothelial and platelet properties.
| . | Endothelium . | Platelets . |
|---|---|---|
| Abbreviations: PDGF, platelet derived growth factor; TGF-β, transforming growth factor-β; IL-1, interleukin-1; VEGF, vascular endothelial growth factor; vWF, von Willebrand factor; CBC, complete blood count; ADP, adenosine diphosphate; ATP, adenosine triphosphate. | ||
| Nucleus | Yes | No (along with red blood cells, the only anucleate cell type in the animal kingdom) |
| mRNA | Lots | Little (though still actively translated into protein)40 |
| Total cell # | 1 × 1012–13 | 2 × 1012 |
| Cell dimensions | Highly variable; up to 100 μM length in large vessels | Diameter ~4 μM Volume 7–12 fL (inversely proportional to platelet count) |
| Life span | Long (months to years) | Short (7–9 days) |
| Daily production | Not known | 2.5 × 1011 |
| Circulating | Few (termed circulating endothelial cells) | Most (normally 1/3 sequestered in spleen; may become sequestered on activated endothelium) |
| Diagnostic markers | Indirect and not clinically useful | CBC, peripheral smear, platelet function studies |
| Origin | Existing endothelial cells; bone marrow | Bone marrow |
| Storage granules | Weibel Palade bodies | α-Granules |
| Dense granules | ||
| Lysosomes | ||
| Partial list of storage components | vWF | vWF P-selectin |
| P-selectin | Multimerin | |
| Multimerin | Fibrinogen, PDGF, TGF-β, IL-1 | |
| VEGF, angiopoeitin, RANTES, PF4, ADP, ATP, serotonin | ||
| . | Endothelium . | Platelets . |
|---|---|---|
| Abbreviations: PDGF, platelet derived growth factor; TGF-β, transforming growth factor-β; IL-1, interleukin-1; VEGF, vascular endothelial growth factor; vWF, von Willebrand factor; CBC, complete blood count; ADP, adenosine diphosphate; ATP, adenosine triphosphate. | ||
| Nucleus | Yes | No (along with red blood cells, the only anucleate cell type in the animal kingdom) |
| mRNA | Lots | Little (though still actively translated into protein)40 |
| Total cell # | 1 × 1012–13 | 2 × 1012 |
| Cell dimensions | Highly variable; up to 100 μM length in large vessels | Diameter ~4 μM Volume 7–12 fL (inversely proportional to platelet count) |
| Life span | Long (months to years) | Short (7–9 days) |
| Daily production | Not known | 2.5 × 1011 |
| Circulating | Few (termed circulating endothelial cells) | Most (normally 1/3 sequestered in spleen; may become sequestered on activated endothelium) |
| Diagnostic markers | Indirect and not clinically useful | CBC, peripheral smear, platelet function studies |
| Origin | Existing endothelial cells; bone marrow | Bone marrow |
| Storage granules | Weibel Palade bodies | α-Granules |
| Dense granules | ||
| Lysosomes | ||
| Partial list of storage components | vWF | vWF P-selectin |
| P-selectin | Multimerin | |
| Multimerin | Fibrinogen, PDGF, TGF-β, IL-1 | |
| VEGF, angiopoeitin, RANTES, PF4, ADP, ATP, serotonin | ||