Seeding endothelial progenitor cells on a self-expanding metal stent: an in vitro study

To demonstrate the feasibility of seeding a self-expanding metal stent with endothelial progenitor cells to enhance rapid reendothelialization, which is postulated to prevent local thrombus formation and restenosis after vascular intervention.

Endothelial progenitor cells and fibrinogen were isolated from the peripheral blood of a domestic swine and then cultured and identified. Ten self-expanding nitinol stents were incubated in the culture medium with a cell concentration of 1 x 10(6)/mL with (n = 5, study group) or without (n = 5, control group) fibrin gel (5 mg/mL fibrinogen and 0.10 NIHU/mL thrombin) for 24 hours. The cell coverage of the stents was documented with en face photography and scanning electron microscopy. After simulated use in vitro, the cells were removed from each stent, counted with a cytometer, sequentially cultured for three passages, and identified again to compare their properties with those of the original seeding line.

After seeding the stent with the combination of endothelial progenitor cells and the fibrin gel coating, the stents took on a tube-like appearance with a confluent monolayer membrane. After digestion with trypsin, a mean of 2.5 x 10(5) +/- 1.3 cells were obtained from the fibrin gel stent (study group); fewer cells (4 x 10(4) +/- 1.5) were recovered from the bare stents (control group) (P < .01). The recovered cells, after amplification with culture, demonstrated the properties of the original endothelial progenitor cells.

An endothelial progenitor cell-coated stent can be successfully fabricated by using fibrin gel as the bonding agent in vitro. Further in vivo research is warranted.