DETECTION OF ENDOTOXIN IN MEDIA FROM STERILE CORNEAL ORGAN-CULTURES

Lipopolysaccharides (LP) are elements of the cell wall of gram-negativ e bacteria. They are also called endotoxins and are known to stimulate various inflammatory reactions by interaction with cytokines and macr ophages, Additionally, they may have a direct effect on other cells, A s contamination of sterile organ-culture media with bacterial substanc es may influence the donor-tissue prognosis, we investigated a series of culture media drawn from organ culture for the presence of endotoxi n. A total of 341 samples of sterile organ-culture media from 3 differ ent cornea banks using either organ culture or the refrigerated-storag e technique were tested for endotoxin. The assay was performed using t he Limulus amebocyte-lysate test, A level of endotoxin above the backg round threshold was found in 99/341 (29%) culture media, The incidence of endotoxin ranged from 14% up to 50%, depending on the cornea bank and culture system used. Endotoxin detected in sterile corneal organ c ultures probably derives from nonreplicating bacterial postmortem dono r-tissue contamination. The presence of endotoxin-positive cultures va ried between the eye banks but was not related to a given storage meth od. As endotoxin may directly influence graft viability or trigger inf lammatory host responses, these findings may have significance for the clinical results of corneal grafting.