Effect Of Recombinant Human Leptin On Megakaryocyte In Patients With Chronic Idiopathic Thrombocytopenic Purpura

Effect of recombinant human leptin on megakaryocyte in patients with chronic idiopathic thrombocytopenic purpuraBackground and Objectives Idiopathic thrombocytopenic purpura (ITP) is a chronic acquired autoimmune hemorrhagic disease characterized by the production of antibodies against platelets, resulting in destruction of the platelets by reticuloendothelial system. The pathogenesis is very complex. Generally it is recognized that immunity is the main reason but the production of platelet is also related closely to normal apoptosis of megakaryocyte. There has been no much research about changes of megakaryocyte and hematopoiesis up to now. Leptin plays an important role in hematopoiesis and immunocyte. We have found increased serum leptin level in patients with ITP and it is negatively related to platelet count , in positive correlation to platelet-associated antibody IgG. The aim of this study is to explore whether leptin plays a role in megakaryocyte of ITP.Methods Megakaryocytic leukemia cell line M07e, megakaryocyte differentiated from bone marrow CD34~+ cells of CITP were used in this study. The mRNA expression of leptin receptor(ob-R) in M07e was detected by RT-PCR. The Proliferative effect of leptin on M07e was investigated with Brdu—ELISA assay and the apoptosis of cells was measured with flow cytometry after Annexin V labeling and PI staining .Bone marrow CD34~+ cells were selected by magnetic cell sorting (MACS), and TPO, SCF were used in the expansion system of megakaryocyte progenitor. The influences of leptin on the expression of megakaryocytic specific monoclonal antibodies CD41a , CD61 and the apoptosis of megakaryocyte were measured with flow cytometry.Results There was mRNA expression of ob-RL and ob-RS in M07e. Leptin promoted the proliferation of M07e in a dose and time dependent manner. The effect of proliferation was the most significant at the concentration of 100ng/ml and after cultured for 48h. Leptin inhibited the apoptosis of M07e. Compared with the control group, leptin had no effect on the expression of CD41a , CD61 and the apoptosis of megakaryocyte during the period of megakaryocyte differentiation from bone marrow CD34~+ cells of CITP.Conclusions Leptin may play an important role in human megakaryocytic leukemia by promoting the proliferation and inhibiting the apoptosis of M07e. Leptin had no synergistic effect on megakaryocyte differentiation of ITP induced by TPO and SCF. There was also no significant influence on the apoptosis of CD41a~+ cells. Clinical significance of bleeding grading in patients with idiopathic thrombocytopenic purpuraObjective To explore the clinical significance of bleeding grading in idiopathic thrombocytopenic purpura(ITP).Methods We developed bleeding grading for 225 patients with ITP by means of ITP bleeding grading standard we drew out and demonstrated its relationship with platelet count and curative effect by means of bivariate.Results The most frequent bleeding site is skin and the occurrence of life-threatening hemorrhage is a rare event in ITP. Bleeding grading is inversely proportional to the platelet count and in direct proportion to the curative effect. But there are no close correlativities.Conclusions Bleeding severity in ITP is not absolutely inversely proportional to the platelet count. Bleeding severity is more important than platelet count. Bleeding grading helps to monitor hemorrhage, make management decisions and predict curative effect.