Bacterial lipopolysaccharides in sterile corneal organ-culture media.
OBJECTIVE
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.


CONCLUSIONS
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.
Sobottka Ventura
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Augen- und Poliklinik des Inselspitals, Universität Bern, Switzerland.
Böhnke
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D002102:Cadaver; D003315:Cornea; D003470:Culture Media / Q000737:chemistry*; D004340:Drug Contamination; D006801:Humans; D008033:Limulus Test; D008070:Lipopolysaccharides / Q000032:analysis*; D009924:Organ Culture Techniques; D013997:Time Factors; D014019:Tissue Donors; D014021:Tissue Preservation
D003470:Culture Media; D008070:Lipopolysaccharides