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Bacterial components inhibit fibroblast proliferation in vitro
E M Edds1, T M Bergamini, K R Brittian
1Department of Surgery, University of Louisville School of Medicine and Veterans Administration Medical Center, KY 40202, USA.
Abstract:
Perigraft fluid from Staphylococcus epidermidis infected grafts in a mouse model significantly inhibits fibroblast proliferation (60-98% at 7 and 28 days), compared with perigraft fluid from sterile grafts. The fibroblast inhibitor was trypsin-heat resistant and dependent primarily upon the bacteria, not the host proinflammatory mediators or the vascular graft biomaterial. We tested the inhibitory properties of S. epidermidis strains RP62A (slime producer) and RP62NA (nonslime producer) and Staphylococcus aureus strain 502a, using an in vitro tritiated thymidine murine fibroblast (ATCC CCL-12) proliferation assay. Whole killed bacteria, disrupted bacteria (live and killed), bacterial supernatants, and purified cell wall products (peptidoglycan, teichoic acid, and lipoteichoic acid from disrupted bacteria) were studied. Significant fibroblast inhibition occurred for all three bacterial strains with disrupted bacteria (live or killed) and cell free bacteria derived supernatants. The fibroblast inhibitor from disrupted slime producing S. epidermidis was trypsin-heat resistant. The fibroblast inhibitor from disrupted S. aureus and supernatants for all three bacterial strains at 1 x 10(7) were trypsin-heat sensitive. Fibroblast inhibition was not dependent upon bacterial viability and not mediated by bacterial cell wall products. In conclusion, components of slime and nonslime producing S. epidermidis and S. aureus inhibit fibroblast proliferation.
Insights
Perigraft fluid from Staphylococcus epidermidis infected grafts inhibits fibroblast proliferation. This bacterial inhibitor is not dependent on host factors or graft material, suggesting a direct bacterial mechanism.
Area of Science:
- Microbiology
- Biomaterials Science
- Cell Biology
Background:
- Vascular graft infections can lead to complications.
- Bacterial factors may influence host tissue response around grafts.
Purpose of the Study:
- To investigate the effect of perigraft fluid from Staphylococcus epidermidis infected grafts on fibroblast proliferation.
- To identify the source and nature of fibroblast inhibitors in infected perigraft fluid.
Main Methods:
- Mouse model of infected vascular grafts.
- In vitro proliferation assay using murine fibroblasts (ATCC CCL-12) and tritiated thymidine.
- Testing of whole bacteria, disrupted bacteria, bacterial supernatants, and cell wall products from S. epidermidis and Staphylococcus aureus.
Main Results:
- Perigraft fluid from S. epidermidis infected grafts significantly inhibited fibroblast proliferation.
- Fibroblast inhibition was primarily dependent on bacteria, not host mediators or biomaterial.
- Disrupted bacteria and bacterial supernatants from S. epidermidis and S. aureus inhibited fibroblast proliferation.
- The inhibitor from disrupted slime-producing S. epidermidis was trypsin-heat resistant, while others were sensitive.
Conclusions:
- Components from both slime-producing and non-slime-producing S. epidermidis, as well as S. aureus, inhibit fibroblast proliferation.
- Bacterial factors, rather than host or graft material, are responsible for fibroblast inhibition.
- These findings suggest a direct bacterial mechanism impacting tissue integration around infected grafts.