We evaluated the acute effects of various solutions with high osmotic concentrations on the proliferation of human peritoneal mesothelial cells (HPMC) in vitro culture. HPMC proliferation was assessed by the ³Hthymidine incorporation. Damage to the HPMC membrane was measured by augmented release of the cytosolic enzyme lactic dehydrogenase (LDH). The various osmotic solutions included the crystalloid agents (glucose, raffinose, sorbitol, sucrose, mannitol, glycerol, a mixture of essential amino acids) at 50mM or 100mM and oncotic agents (dextran 70, maltodextrin, hydroxyethylstarch 20) at 3.5% or 7%.
All of the solutions with high osmotic concentrations at neutral pH inhibited the growth of HPMC in a concentration-dependent way. The inhibition by the crystalloid agents was stronger than that by the oncotic agents. The amino acids caused very strong inhibition of HPMC growth. At the higher concentration (100mM), most of crystalloid agents also damaged the HPMC membrane, but no significant injury to HPMC was observed at the higher concentration (7%) of the oncotic agents.
The results suggest that the toxic effect of the osmotic solutes on the proliferation of HPMC depends on the hyperosmolality. However, we cannot exclude a toxic metabolic effect on the cells. The oncotic solutes seem to be less toxic for mesothelial cell proliferation.