A promising and incompletely explored approach to fibrosis control utilizes biomaterials that modulate healing. Expanded polytetrafluoroethylene (ePTFE) is a highly stable polymer of tetrafluoroethylene that was patented by Gore.
Due to its biocompatibility, biostability, and high compliance, ePTFE incorporates well into many tissues and is approved for use in numerous biomedical implants, including: vascular grafts, bypass grafts, hernia membranes, and sutures. ePTFE has a porous surface comprised of nodes and fibrils which can structurally permit or prevent cellular integration.
Implants of matching footprints were fabricated from silicone (Control) and novel, bi-layered ePTFE.
ePTFE
implants included: (a) one that inflated with aqueous humor (AH) (High), (b)
one that inflated with a lower profile (Low), (c) an uninflated implant not
connected to the anterior chamber (Flat), and (d) one filled with material that
did not allow AH flow (Filled).
- The permeability of tissue capsules surrounding GDIs was assessed using constant-flow perfusion with fluoresceinated saline at physiologic flow rates.
- After sacrifice, quantitative histopathological measures of capsule thickness were compared among devices, along with qualitative assessment of cellular infiltration and inflammation.
- Capsular
thickness was significantly reduced in blebs over ePTFE (61.4 ± 53 μm) versus silicone implants (193.6 ± 53 μm, p = .0086).
- AH
exposure did not significantly alter capsular thickness, as there was no
significant difference between High and Filled (50.9 ± 29, p = .34)
implants.
- Capsules around ePTFE implants demonstrated permeability with steady-state pressure: flow relationships at physiologic flow rates and rapid pressure decay with flow cessation, while pressure in control blebs increased even at low flow rates and showed little decay.
- Perfused fluorescein dye appeared beyond the plate border only in ePTFE implants.
 |
| Steady fluorescein outflow beyond the ePTFE implant |
In conclusion, ePTFE implants are associated with thinner, more permeable capsules compared to silicone implants simulating presently used devices.
ARTICLE LINK: https://aiche.onlinelibrary.wiley.com/doi/full/10.1002/btm2.10179
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