Journal: JVS-Vascular Science

Article Title: Biological mechanisms of infection resistance in tissue engineered blood vessels compared to synthetic expanded polytetrafluoroethylene grafts

doi: 10.1016/j.jvssci.2023.100120

Figure Lengend Snippet: Representative hematoxylin and eosin ( H&E ), Gram stain, and immunofluorescence images of explanted human acellular vessels ( HAV ) and expanded polytetrafluoroethylene ( ePTFE ) dialysis access conduits, determined to be infected approximately 1 year after implantation in a phase III clinical trial. H&E images show multiple cannulation tracts (blue arrows) from dialysis access through the wall of both the HAV (A-C) and ePTFE graft (G-I) . A few clusters of gram-positive bacteria (dark blue) were identified in the thrombus and fibrous tissue but not seen within the wall of the HAV explant ( D-F , green arrows). Numerous clusters of bacteria were found inside the wall (K) and within the luminal pannus tissue (L) of the ePTFE graft. The black and red dashed line boxes on the low-magnification images (A, D, G J) correspond with regions shown in color labeled high-magnification H&E and gram stain images. Immunostaining for neutrophils (green) and Staphylococcus aureus bacteria (red) in the HAV (M) and ePTFE (N) explants are shown at high magnification near regions identified with green dashed-line boxes in low-magnification images (A, G) . Neutrophils were typically found both outside and inside of the HAV (M) , but only along the exterior and not within the contaminated ePTFE graft (N) . 4′,6-Diamidino-2-phenylindole (DAPI) stained cell nuclei (blue) as well as diffuse extracellular nuclear material into edge of ePTFE (N) which suggested a loss of neutrophil viability or NETosis at this interface.

Article Snippet: Samples were stained with anti- Staphylococcus aureus ( S.aureus ) (NOVUS NB100-64,499, diluted 1:100) and anti-neutrophil elastase (R&D Systems MAB91671-100, diluted 1:50) overnight at 4°C.

Techniques: Staining, Immunofluorescence, Infection, Bacteria, Labeling, Immunostaining

Journal: JVS-Vascular Science

Article Title: Biological mechanisms of infection resistance in tissue engineered blood vessels compared to synthetic expanded polytetrafluoroethylene grafts

doi: 10.1016/j.jvssci.2023.100120

Figure Lengend Snippet: Representative Gram stain images and immunohistochemical ( IHC ) localization of neutrophils and Staphylococcus aureus ( S. aureus ) from a human acellular vessel ( HAV ) and expanded polytetrafluoroethylene ( ePTFE ) explant 2 weeks after implantation in a rodent infection model. Gram-positive S . aureus (dark blue clusters) were identified within interstices of ePTFE (B) but not seen within or around HAV explant (A) . Immunostaining for neutrophil elastase (green) and S . aureus (red) is shown in (C-F) and (G-J) . The HAV explant had only a few intact neutrophils on the tissue and graft interface (D) , but host cells (blue nuclei) infiltrated into the entire HAV wall (C and E) , unlike that of the ePTFE wall (G) . Numerous clusters of S . aureus were found within the ePTFE wall (G and I) , but no bacteria were detected in the HAV (C) . Some positive neutrophil elastase staining was observed just at the edge of the ePTFE wall, but relatively few intact nuclei were found to be associated with this staining (H) . The tissue surrounding the actively contaminated ePTFE explant (J) had a high density of neutrophil elastase-positive neutrophils compared with that of the HAV implant (F) . The green arrow in (C) shows autofluorescent red blood cells.

Article Snippet: Samples were stained with anti- Staphylococcus aureus ( S.aureus ) (NOVUS NB100-64,499, diluted 1:100) and anti-neutrophil elastase (R&D Systems MAB91671-100, diluted 1:50) overnight at 4°C.

Techniques: Staining, Immunohistochemical staining, Infection, Immunostaining, Bacteria