Sphingosine and sphinganine levels in human mesothelial cells in vitro as a potential index of signal transduction pathways impacted by microbes and osmolality.

Sphingolipids are emerging as important regulators of mammalian cell biology. In this study, the contents of six separate preparations of human omental mesothelial cells in vitro were examined for free sphingosine and sphinganine, and for the total levels of these sphingoid bases in ceramide-containing sphingolipids. Two high-performance liquid chromatography (HPLC) methods for determination of sphingoid base levels in cultured cells were compared. The rapid-HPLC method was found to yield the highest recovery of internal standard. Mesothelial cells initially isolated by collagenase digestion of the omentum were found to have higher free- and total-sphingoid base levels than cells isolated by trypsin-EDTA digestion. Use of sphingoid base levels to gain insights into the status of cellular nutrition, inflammation, programmed cell death, exposure to microbial toxins, cytokines, and growth factors within the peritoneum will require a systematic description of sphingolipids in normal, diseased, and dialyzed mesothelium.