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Loss of seeded endothelial cells in vivo. A study of Dacron grafts under different flow conditions
1Department of Surgery, Lund University, Malmö General Hospital, Sweden.
Insights
Endothelial cell loss from Dacron grafts was similar in sheep carotid arteries under both low and normal blood flow conditions. This study found no significant difference in cell retention between restricted and unrestricted flow rates over two hours.
Area of Science:
- Vascular surgery
- Biomedical engineering
- Cell biology
Background:
- Endothelial cell seeding of vascular grafts aims to improve patency and reduce thrombosis.
- Understanding the impact of hemodynamic conditions on cell retention is crucial for graft design and clinical success.
Purpose of the Study:
- To evaluate the in vivo retention of endothelial cells seeded onto Dacron grafts under varying arterial flow rates.
- To compare endothelial cell loss in Dacron grafts subjected to low, restricted arterial flow versus normal, unrestricted flow.
Main Methods:
- Sheep carotid arteries were implanted with Dacron grafts seeded with Indium-111-oxine labeled endothelial cells.
- Two flow conditions were established: restricted flow (50 ml/minute) and unrestricted flow (120-180 ml/minute).
- Radioactivity over the grafts was measured for 2 hours to quantify endothelial cell loss.
Main Results:
- An initial rapid loss of approximately 20% of endothelial cells was observed, followed by a slower loss reaching about 50% by 2 hours.
- No significant difference in endothelial cell loss was detected between grafts exposed to low flow and those with unrestricted flow.
- All grafts remained patent, with no significant differences in thrombus formation between the two flow conditions.
Conclusions:
- Arterial flow rate (50 ml/minute vs. 120-180 ml/minute) does not significantly affect the in vivo retention of endothelial cells seeded onto Dacron grafts.
- These findings suggest that hemodynamic shear stress at these tested levels may not be the primary determinant of early endothelial cell loss in seeded grafts.
Objectives:
To assess, in vivo, the loss of endothelial cells seeded in a Dacron graft at low, restricted arterial flow and at normal unrestricted flow.
Design And Setting:
Laboratory animal study.
Materials:
Indium-111-oxine labelled endothelial cells were seeded in externally supported, preclotted Dacron grafts, inserted as interposition grafts in the carotid arteries of nine sheep. Activity (radioactivity) was measured, flow established, on one side unrestricted 120-180 ml/minute, and on the other restricted to 50 ml/minute by a distal clamp.
Outcome Measures:
The reduction in activity over the grafts was measured for 2 hours.
Results:
There was an immediate loss of activity to around 80% and thereafter a lower rate of cell loss to around 50%. No difference could be demonstrated in the loss from low flow compared to high flow grafts. All grafts were patent. There was no difference in thrombus weights.
Conclusion:
No difference could be demonstrated in seeded endothelial cell loss from a Dacron graft in vivo at low flow (50 ml/minute) compared with unrestricted flow (120-180 ml/minute).