Glial cells production of inflammatory mediators induced by streptococcus pneumoniae: Inhibition by pentoxifylline, low-molecular-weight heparin and dexamethasone

Exposure of primary rat glial cells to beat inactivated Streptococcus pneumoniae, induced dose-dependent production of tumor necrosis factor α (TNFα), nitric oxide (NO) and prostaglandin E₂ (PGE₂). Concomitant addition of the bacterium and the synthetic glucocorticoid dexamethasone resulted in complete suppression of TNFα, NO and PGE₂ production. Pentoxifylline, a phosphodiesterase inhibitor completely blocked TNFα secretion, whereas NO and PGE₂ were not affected. Low-molecular-weight heparin enoxaparin caused 25-64% inhibition in TNFα production, up to 30% inhibition of NO secretion and a 10% reduction in PGE₂. Thus, Streptococcus pneumoniae, the pathogen most commonly associated with meningitis in the Western world can be added to the list of agents causing direct stimulation of glial cells. Pentoxifylline and enoxaparin in addition to dexamethasone may limit the central nervous system local inflammatory responses and could improve the effort towards reducing the dismal outcome of patients with pneumococcal meningitis.