Table 1 Development of endothelial cells, collagenization ratio, and mean thickness of the LL.
| − | + | ⧺ | ⧻ | |
|---|---|---|---|---|
| Number of endothelial cells over the whole surface of the LL | 0 | <50 | 50–99 | ≥100 |
| Collagenization ratio of the LL (%) | 0 | <50 | 50–99 | 100 |
| Mean thickness of the LL (µm) | <100 | 100–199 | 200–399 | ≥400 |
| LL: luminal layer | ||||
| Mechanical properties of the SF/SF and the ePTFE grafts (±standard deviation) | ||||
| Water permeability (mL/min/cm2 120 mmHg) | Circumferential strength (N/mm2) | Longitudinal strength (N/mm2) | Compressive elastic modulus (N/mm2) | |
| SF/SF | 50.0±1.0 | 48.0±2.0 | 8.0±1.0 | 0.008±0.002 |
| ePTFE | 51.0±1.0 | 51.0±1.0 | 7.0±1.0 | 0.008±0.003 |
| SF/SF: silk fibroin-coated silk fibroin tubes; ePTFE: expanded polytetrafluoroethylene | ||||
| Histological appearance of luminal layers in the graft | ||||
| Length of time | Grafts | Luminal layer | ||
| Number of ECs | Collagenization | Thickness | ||
| 1 week | SF/SF | − | − | + |
| ePTFE | − | + | ||
| 3 weeks | SF/SF | ⧺ | + | + |
| ePTFE | + | + | ||
| 3 months | SF/SF | ⧻ | ⧻ | + |
| ePTFE | ⧺ | + | ||
| SF/SF: silk fibroin-coated silk fibroin tubes; ePTFE: expanded polytetrafluoroethylene; EC: endothelial cell | ||||