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Bacterial lipopolysaccharides in sterile corneal organ-culture media
A C Sobottka Ventura1, M Böhnke
1Augen- und Poliklinik des Inselspitals, Universität Bern, Switzerland.
Purpose:
Lipopolysaccharides (LPS) are known to stimulate various inflammatory reactions by interaction with cytokines and macrophages. As contamination of sterile organ culture media with nonviable bacterial substances may influence donor tissue prognosis, we investigated a series of culture media drawn from organ culture for the presence of LPS.
Methods:
One hundred eighty-two samples of sterile organ-culture media were tested for LPS using the Limulus-amoebocyte-lysate assay (LALA). We then investigated the time course of LPS levels during organ culture, the influence of medium changes, the graft deswelling procedure and transportation as well as repeated freezing on the detection of lipopolysaccharides with the LALA.
Results:
LPS above background threshold was found in 21.4% of the organ-culture media. The time course of LPS during organ culture and through the deswelling procedure was quite stable. Medium changes may wash out LPS, thus the highest LPS values were normally seen in the examination medium, which has the first contact with the corneal tissue. Repeated freezing did not influence the detectability of LPS with the LALA.
Conclusion:
LPS detected in sterile corneal organ cultures is probably derived from nonreplicating bacterial postmortem donor tissue contamination. It is a rather heat and cold stable product that may be washed out from the donor tissue by medium changes. As LPS may directly influence graft viability or trigger inflammatory host responses, further investigations of the clinical course of these grafts are required.
Insights
Lipopolysaccharides (LPS) were found in 21.4% of sterile organ culture media, likely from bacterial contamination. LPS is heat and cold stable, potentially impacting graft viability and host inflammatory responses.
Area of Science:
- Ophthalmology
- Microbiology
- Immunology
Background:
- Lipopolysaccharides (LPS) trigger inflammatory responses via cytokines and macrophages.
- Contamination of sterile organ culture media with bacterial substances can affect donor tissue prognosis.
Purpose of the Study:
- Investigate the presence of LPS in culture media from organ cultures.
- Assess the impact of various factors on LPS detection during organ culture.
Main Methods:
- Tested 182 samples of sterile organ-culture media for LPS using the Limulus-amoebocyte-lysate (LALA) assay.
- Analyzed LPS levels over time, during medium changes, deswelling, transportation, and after repeated freezing.
Main Results:
- LPS was detected above background levels in 21.4% of organ-culture media.
- LPS levels remained stable during organ culture and deswelling procedures.
- Medium changes potentially reduced LPS, with highest values in initial examination media; freezing did not affect detection.
Conclusions:
- Detected LPS in sterile corneal organ cultures likely originates from non-replicating bacterial contamination in postmortem donor tissue.
- LPS is a heat- and cold-stable contaminant that can be removed by medium changes.
- Further research is needed to understand the clinical impact of LPS on graft viability and host inflammatory responses.