Related Experiment Videos
Leukocyte spreading behavior on vascular biomaterial surfaces: consequences of chemoattractant stimulation
C C Chang1, S M Lieberman, P V Moghe
1Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, NJ 08854-8058, USA.
Abstract:
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.
Insights
Chemoattractant stimulation alters how human white blood cells (polymorphonuclear leukocytes or PMN) spread on biomaterials, affecting their ability to fight bacterial infections. This response depends on the material
Area of Science:
- Biomaterials Science
- Immunology
- Cell Biology
Background:
- Polymorphonuclear leukocytes (PMN) play a crucial role in combating bacterial infections on implantable vascular biomaterials.
- Understanding PMN behavior on these materials is vital for improving device efficacy and patient outcomes.
Purpose of the Study:
- To investigate the spreading behavior of human PMN on expanded polytetrafluoroethylene (ePTFE) pretreated with plasma proteins.
- To analyze the effects of the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (fMLP) on PMN morphology and function.
Main Methods:
- Developed a novel imaging configuration for in situ reconstructive analysis of PMN 3-D morphology on ePTFE using confocal microscopy.
- Studied PMN spreading and attachment in response to fMLP stimulation on ePTFE treated with various plasma proteins (albumin, fibrinogen, immunoglobulin-G).
- Assessed PMN phagocytosis of unopsonized particles following fMLP stimulation.
Main Results:
- fMLP stimulation enhanced PMN morphological polarity on most substrates, except fibrinogen-treated ePTFE.
- PMN spreading and substrate attachment were significantly altered by fMLP in a substrate-dependent manner.
- fMLP-induced PMN spreading modulation enhanced unopsonized particulate phagocytosis on untreated and albumin-treated ePTFE.
Conclusions:
- Chemoattractant stimulation profoundly influences PMN spreading attributes (polarity, attachment, 3-D morphology) on ePTFE surfaces in a substrate-specific manner.
- These chemoattractant-induced spreading responses are linked to altered PMN phagocytic capacity.
- Substrate-dependent modulation of PMN behavior is critical for controlling biomaterial-associated infections.