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Platelets. 2006 Aug;17(5):283-8.

Endogenously generated reactive oxygen species reduce PMCA activity in platelets from patients with non-insulin-dependent diabetes mellitus.

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1
Department of Physiology, University of Extremadura, 10071 Cáceres, Spain.

Abstract

Intracellular Ca2+ homeostasis in platelets of patients with non-insulin-dependent diabetes mellitus (NIDDM) has been reported to be altered, leading to an increased adhesiveness and spontaneous aggregation. Among the disturbed Ca2+ mechanism in platelets from NIDDM subjects, a reduced Ca2+ extrusion by the plasma membrane Ca2+-ATPase (PMCA) is especially relevant, maintaining an elevated cytosolic free Ca2+ concentration that results in platelet hypersensitivity. Here we show that treatment of platelets from NIDDM patients with 300 U/mL catalase or 5 mM D-mannitol, which prevent H2O2- and hydroxyl radicals-mediated oxidative stress, respectively, increases Ca2+ extrusion after treatment with thapsigargin (TG) plus ionomycin (Iono). In contrast, 1 mM trolox, a scavenger of ONOO-, did not alter TG + Iono-induced response. Catalase and D-mannitol reversed the enhanced tyrosine phosphorylation of PMCA induced by TG + Iono in NIDDM patients. These findings open up new horizon for the development of therapeutic strategies to palliate cardiovascular disorders in NIDDM.

PMID:
16928598
DOI:
10.1080/09537100600745187
[Indexed for MEDLINE]

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