L-CYSTEINE IMPROVES GROWTH OF HUMAN PERITONEAL MESOTHELIAL CELLS IN-VITRO

Objective: To improve the growth characteristics of human peritoneal m esothelial cells (HPMC). Design: The effect of commonly used agents,L- cysteine and epidermal growth factor (EGF), added individually (''sing le'') or mixed with hydrocortisone and ape-transferrin (''admixture'') in the culture medium (M199)on cultured HPMC, was investigated. Metho ds: Growth agents were added to M199 medium along with 2% fetal bovine serum and L-glutamine. Growth was determined by the analysis of thymi dine ([methyl-3H] thymidine) incorporation into deoxyribonucleic acid, total cell protein, and by cell counts. Morphology was assessed by ph ase contrast light microscopy and scanning electron microscopy. Result s: HPMC exposed to L-cysteine 0.25 x 10(-3) mol/L (30 mu g/mL) exhibit ed significantly improved attachment and growth. Attached cells appear ed flat and well spread out shortly after seeding, and produced a tigh t polygonal monolayer in 14 days, in contrast to the growth of HPMC in control M199 medium, which failed to reach confluence. After an initi al lag period in cell growth, EGF (0.01 mu g/mL) produced a greater in crease in cell growth than L-cysteine did; however, this was associate d with changes in HPMC morphology. During the growth period (14 days), EGF-stimulated HPMC appeared distorted and irregular compared to L-cy steine-treated cells, which had the characteristic tight ''cobblestone '' appearance. Conclusion: L-cysteine improved cell attachment with pr eservation of the characteristic morphology of HPMC. Epidermal growth factor improved cell growth but produced changes in morphology. The ad dition of L-cysteine to the culture medium has an important cell growt h enhancement role due to the improved cell attachment and cell viabil ity.