PubMed · 3537144
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C Dufour, J L Davin, C Bouchet, J J Rambeaud, J L Magne, G Faure. 1986. [Transvesical bypass].. https://pubmed.ncbi.nlm.nih.gov/3537144/
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To establish the optimal conditions for achieving endothelial cell coverage of the luminal surfaces of small-caliber vascular grafts in vitro, the attachment of endothelial cells (ECs) cultured from human umbilical veins to polytetrafluoroethylene (PTFE) grafts was studied. Cell attachment and spreading were compared after PTFE grafts were (a) precoated with fibronectin (HFN), type I collagen, type IV collagen, plasma and fibrin with or without thrombin, singly or in combination; (b) seeded with cell densities varying from 0.5 x 10(5) to 6 x 10(5) cells/cm2; and (c) incubated at 30, 60, or 90 min. Cell coverage and spreading were assessed by means of scanning electron microscopy. Quantification of graft surface coverage was performed with computer-assisted image analysis. To determine optimal conditions of endothelialization among the 189 treatment combinations, analysis of variance was used. We conclude that a virtually confluent cell monolayer can be established on small-caliber PTFE grafts when precoated with fibrin glue or plasma, seeded with cell densities >/=4 x 10(5) cells/cm2, and incubated for 60 min. These parameters are compatible with an operating room vascular procedure.
Chemoattractant-induced phenomena of polarity and migration of polymorphonuclear leukocytes (PMN) are believed to play a key physiological role in controlling bacterial infections on implantable vascular biomaterials. Our study targeted the spreading behavior of human PMN adherent to expanded polytetrafluoroethylene (ePTFE), pretreated with various plasma proteins, in response to the chemoattractant, N-formyl-methionyl-leucyl-phenylalanine (fMLP). To this end, a novel imaging configuration was developed to allow in situ reconstructive analysis of PMN 3-D morphology on opaque ePTFE surfaces, using optical sectioning confocal microscopy. Following fMLP stimulation, PMN morphological polarity was enhanced on all substrates studied except fibrinogen treated ePTFE. 3-D PMN morphometry revealed that in the absence of fMLP, overall cell spreading was minimized on albumin-treated ePTFE and maximized on fibrinogen and immunoglobulin-G-treated ePTFE. Following fMLP stimulation, overall PMN spreading increased markedly on untreated and albumin-coated ePTFE, while it stayed invariant on IgG and plasma treated ePTFE, and decreased on fibrinogen-treated ePTFE. Spatial analysis of PMN spreading following fMLP stimulation revealed enhanced PMN attachment on untreated and albumin treated ePTFE and diminished attachment on fibrinogen and plasma treated ePTFE. Thus, chemoattractant stimulation altered a wide range of PMN spreading attributes on ePTFE, including morphological polarity, substrate attachment, and 3-D membrane spreading, in a substrate dependent manner. These chemoattractant-induced spreading responses may also have important consequences for PMN phagocytosis. We report that fMLP stimulation led to enhanced unopsonized particulate phagocytosis on untreated and albumin treated ePTFE, but caused no discernible change in phagocytosis on other protein substrates. Thus, chemoattractant modulation of PMN spreading on ePTFE is highly substrate-regulated, and manifests in concerted effects on PMN phagocytosis.
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