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Fig. 3 | Cardiovascular Diabetology

Fig. 3

From: PAR-4/Ca2+-calpain pathway activation stimulates platelet-derived microparticles in hyperglycemic type 2 diabetes

Fig. 3

Effect of PAR agonists on Ca2+ mobilization and calpain activity in platelets from T2DM. a–d Effect of PAR agonists on intracellular Ca2+ in platelets of GGC and PGC T2DM. Cells were loaded with Fura-2 and placed in a thermostated cuvette in a physiological buffer. a, b Representative tracing of intracellular Ca2+ (Ca2+i) from platelets, by fluorimetric measurements. TRAP-6 (PAR-1 agonist, 20 μM) and AY-NH2 (PAR-4 agonist, 200 μM) were added when baseline fluorescence was stable. Red lines indicate Ca2+i of platelets of GGC T2DM, and blue lines indicate Ca2+i of platelets of PGC T2DM. c, d Ca2+ peak values, and time of Ca2+ recovery in platelets from T2DM with GGC and with PGC, respectively. t 50%, half-time of recovery; t 100% total time of recovery. e Calpain activity in platelets from T2DM with PGC, stimulated with AY-NH2 (200 μM) and in the presence of calpain inhibitor (ALLN, 100 μM). Calpain activity was determined as the value of luminescence recorded as relative light units (RLU) per µg of protein lysate. f Counts of platelets-derived microparticles (PMP) released by platelets from T2DM with PGC treated with AY-NH2, (PAR-4 agonist), in the presence and in absence of calpain inhibitor, ALLN (n = 21). Values are mean ± SEM. The p-values were evaluated by t-test (c, d, f) or ANOVA (p < 0.0001) followed by a post-hoc Bonferroni test (e)

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