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Harvesting Murine Alveolar Macrophages and Evaluating Cellular Activation Induced by Polyanhydride Nanoparticles
Published on: June 8, 2012
Biomaterial-induced dysfunction in the capacity of rabbit alveolar macrophages to kill Staphylococcus epidermidis
G Giridhar1, Q N Myrvik, A G Gristina
1Medical Sciences Research Institute, Herndon, Virginia 22070, USA.
Abstract:
The effect of poly(methyl methacrylate) (PMMA), titanium alloy, and silicone discs on the capacity of rabbit alveolar macrophages (AM) to kill RP12 strain of Staphylococcus epidermidis (RP12) was studied in vitro. When freshly harvested AM were preincubated with PMMA discs for 3 h and subsequently assayed for RP12 killing, there was no change in the RP12 killing capacity of AM. However, when AM were incubated with PMMA discs for 6 or 18 h at 37 degrees C in 5% CO2, the RP12 killing capacity of AM was reduced to 15% and 4%, respectively. Preincubation of AM with titanium alloy for 6 h reduced RP12 killing capacity of AM to 30%, and to 21% in 18-h incubation. Silicone discs did not affect the RP12 killing by AM at 6 h of preincubation, but reduced RP12 killing (35%) by AM when preincubated for 18 h. Preincubation of AM with PMMA discs for 3 or 6 h did not affect the level of PMA-elicited oxidative burst of AM as measured by a luminol-enhanced chemiluminescent assay. Superoxide dismutase, which eliminated the oxidative burst of AM by 90%, did not affect the RP12 killing by AM.
Insights
Poly(methyl methacrylate) (PMMA), titanium alloy, and silicone implants impair rabbit alveolar macrophage (AM) bacterial killing capacity over time. Longer incubation periods significantly reduced AM
Area of Science:
- Biomaterials Science
- Immunology
- Microbiology
Background:
- Alveolar macrophages (AM) are crucial for lung defense against bacteria.
- Biomaterials like PMMA, titanium alloy, and silicone are used in medical implants.
- Understanding implant material interactions with immune cells is vital for clinical success.
Purpose of the Study:
- To investigate the in vitro effects of PMMA, titanium alloy, and silicone on rabbit AM's ability to kill Staphylococcus epidermidis.
- To determine if incubation time influences the impact of these biomaterials on macrophage function.
Main Methods:
- Rabbit AM were co-incubated with PMMA, titanium alloy, or silicone discs for varying durations (3, 6, 18 hours).
- Bacterial killing capacity against Staphylococcus epidermidis (RP12) was assessed.
- PMA-elicited oxidative burst in AM was measured using a luminol-enhanced chemiluminescent assay.
Main Results:
- PMMA significantly reduced AM bacterial killing after 6 and 18 hours of incubation.
- Titanium alloy impaired AM killing capacity at 6 and 18 hours.
- Silicone showed minimal effect at 6 hours but reduced killing at 18 hours.
- The oxidative burst of AM was not significantly affected by PMMA, titanium alloy, or silicone.
Conclusions:
- PMMA, titanium alloy, and silicone biomaterials can suppress the phagocytic capacity of rabbit alveolar macrophages.
- Prolonged exposure to these materials in vitro leads to a diminished ability of AM to clear bacterial infections.
- These findings highlight potential immunomodulatory effects of common implant materials on innate immune cells.
