Macroporous condensed poly(tetrafluoroethylene). I. In vivo inflammatory response and healing characteristics

This study was designed to determine whether the novel spatial geometry of macroporous condensed poly(tetrafluoroethylene) (cPTFE) favorably affects the in vivo repair process. Specifically, the macroporous surface geometry and the reduced material thickness contribute to better healing characteristics. For this purpose, three other materials used for abdominal wall repair were selected, expanded poly(tetrafluoroethylene) (ePTFE), low-weight poly(propylene) (lwPP), and high-weight poly(propylene) (hwPP). Samples of each material (1 x 2 cm, n = 4) were implanted subcutaneously in rats for 7, 28, or 56 days. After sacrificing the animals, at each time point, the tissue implant sites were subjected to morphometric analysis and evaluation of inflammatory and wound-healing tissue characteristics. Although the fibrous capsule thickness did not significantly vary among the four materials (p > 0.05), cPTFE consistently led to the most mature fibrous capsule. However, ePTFE showed the greatest tissue-material integration. Both PP materials presented various levels of tissue integration, but they were characterized by significant early inflammation and increased foreign body reaction around the mesh openings, especially for hwPP. In contrast, cPTFE did not induce extensive inflammation or elevated foreign body reaction around its mesh openings. We conclude that cPTFE combines the inherent PTFE biocompatibility with low polymer surface area (large mesh openings, reduced material thickness) leading to a better inflammatory and wound healing response compared to available materials used in abdominal wall reconstruction.