Preliminary Study on Apoptotic Proteins in Platelet from Adult Patients with Chronic Immune Thrombocytopenic Purpura

Abstract

Background: Adult chronic idiopathic thrombocytopenic purpura (ITP) is a chronic and usually lifelong hemorrhagic disorder in which enhanced platelet destruction and -weakened platelet production lead to thrombocytopenia. In this study, the p38 mitogen-activated protein kinase (p38-MAPK), early growth response 1 (EGR-1), p53, Bcl-xL, Bak, Bax, and reactive oxygen species (ROS) in platelets from adult patients with chronic ITP were investigated.

Methods: Platelets were isolated from blood samples collected from 20 adult patients with chronic ITP and 20 healthy volunteers. p38-MAPK, EGR-1, p53, Bcl-xL, Bak, Bax, and ROS were determined by flow cytometry, and the results were analyzed by EXPO32 ADC.

Results: Flow cytometry showed the expression levels of p38-MAPK (61.66 ± 19.38% vs. 27.52 ± 14.34%), EGR-1 (62.22 ± 20.48% vs. 9.05 ± 5.79%), p53 (56.82 ± 20.07% vs. 4.35 ± 2.04%), Bak (39.86 ± 11.45% vs. 20.82 ± 11.85%), Bax (36.85 ± 15.99% vs. 6.69 ± 5.01%), and ROS (19.98 ± 1.47% vs. 1.29 ± 0.10%) were all elevated (p < 0.05 compared with healthy volunteers). In addition, pro-survival Bcl-xL (5.38 ± 1.52% vs. 21.20 ± 6.04%) was decreased markedly in platelets from adult patients with chronic ITP (p < 0.05 compared with healthy volunteers).

Conclusions: Our findings reveal that platelets in adults with chronic ITP display a proapoptotic gene expression phenotype, based on the enhanced expression of p38-MAPK, EGR-1, p53, Bak, Bax, and ROS, and attenuated expression of Bcl-xL, suggesting increased sensitivity toward apoptosis.

Keywords: Apoptosis; Chronic idiopathic thrombocytopenic purpura; Pathogenesis; Platelets.