Regulatory role of extracellular matrix proteins in neutrophil respiratory burst during aging.

- Tortorella C, Piazzolla G, Spaccavento F, Vella F, Pace L, Antonaci S

Mech Ageing Dev 2000 Oct 20;119(1-2):69-82.

Neutrophil respiratory burst was assessed on plates coated with fibronectin (FN) or laminin (LM), both used at dosages inhibiting polystyrene-triggered cell activation in young healthy volunteers. Under these conditions, a low, yet significant, spontaneous superoxide anion (O(2)(-)) production, matching with enhanced levels of basal adherence, was detected in FN-plated neutrophils of elderly donors. In contrast, although neutrophil stimulation with tumor necrosis factor (TNF)-alpha, granulocyte macrophage-colony stimulating factor (GM-CSF), fMLP or phorbol myristate acetate (PMA) gave rise to a massive and prolonged FN-primed O(2)(-) release, a significant impairment of oxidative response occurred in the aged group as a result of GM-CSF or fMLP cell challenge. Such an effect was not associated to an age-related imbalance of stimulant-triggered neutrophil adhesiveness to FN, even though a larger contribution of CD18-dependent versus CD18-independent pathways was observed in old as compared to young individuals. Notably, within the aged group, anti-CD18 monoclonal antibody cell pretreatment resulted in a higher suppression of FN-primed O(2)(-) release following TNF-alpha with respect to GM-CSF stimulation, thus implying that an agonist-related defect of the coupling between beta2 integrin-dependent adhesive and oxidative events is likely to occur as a feature of age. All physiological mediators failed to activate the respiratory burst of neutrophils plated on LM-coated wells in both young and aged donors. This effect appears to be the result of an active process, since neutrophils from either group of subjects adhered to LM-coated surfaces and LM inhibited in a dose-dependent manner the FN-priming effect on neutrophil O(2)(-) production. All together the findings provide additional evidence for an imbalance of neutrophil-mediated functions in the elderly.

This abstract at PubMed.