Contributions
Abstract: S298
Type: Oral Presentation
Session title: ITP: from bench to bedside
Background
Immune thrombocytopenia (ITP) affects 1-10 in 10000 pregnancies. Although most patients were remaining relatively stable throughout pregnancy, the platelet counts may decrease following the prolongation of gestation, especially in the third trimester. The pathogenesis is usually considered to be secondary to physiologic changes during gestation, such as an increase in blood volume, platelet activation, or increased platelet clearance. However, the precise pathogenesis of ITP during pregnancy has not been fully understood.
Aims
It is to explore the relationship between the high level of estradiol (E2) and defective thrombopoiesis in ITP during pregnancy.
Methods
Twenty consecutive successful pregnancies in 20 ITP patients were studied. Blood samples were analyzed to determine the concentration of E2 at different gestational ages using ELISA. BM-derived CD34+ cells from healthy controls (HCs), ITP patients and pregnant ITP (P-ITP) patients were cultured. BM-derived CD34+ cells from ITP patients were treated with different concentrations of E2. he differentiation of megakaryocytes (MKs) and polyploidization were assessed by flow cytometry. Proplatelet formation (PPF) were observed with a phase-contrast microscope and a confocal microscope. MK apoptosis and markers of apoptosis pathways were detected via flow cytometry, and western blotting was used to evaluated the expression of FoxO1 and Mst1.
Results
P-ITP patients experienced significant reduction in platelet counts during gestation, particularly in the late stages. BM-derived CD34+ cells from HCs, ITP patients and P-ITP patients were sorted and cultured. It was observed that the percentage of CD41+CD42b+ MKs and high ploidy MKs were significantly lower in ITP patients than in HCs. In addition, few MKs with proplatelets were observed in ITP patients. A higher percentage of CD41+CD42b+ MKs and high ploidy MKs were found in P-ITP samples than in ITP samples. However, in P-ITP samples, fewer MKs with proplatelets were observed. The results indicated that the thrombopoiesis ability differed between ITP and P-ITP patients.
The concentration of E2 was founded to be sharply increased during pregnancy in ITP. To explore whether there is a link between the levels of E2 during gestation and thrombopoiesis in ITP patients during pregnancy, BM-derived CD34+ cells from ITP patients were treated with different concentrations of E2, which were determined by the serum levels of P-ITP patients. E2 was observed to dose-dependently promote the MKs differentiation and polyploidization. However, at high E2 levels of 10 nM and 100 nM, few proplatelet-generating MKs were observed. In the 10 nM and 100 nM groups, a high percentage of apoptotic MKs was detected. The physiologic concentration of 0.1 nM had no obvious influence on MKs apoptosis. The expression of Bak, Bax, and cleaved caspase-3, which were components of the intrinsic apoptosis pathway, were significantly increased in the 10 nM and 100 nM groups. Increased apoptotic MKs were also observed in BM biopsy samples from P-ITP patients. These findings indicated that a high concentration of E2 could induced activation of the intrinsic apoptosis pathway in ITP MKs and impaired PPF. The activation of the Mst1-FoxO1 axis, which induced activation of the intrinsic apoptosis pathway, was found in ITP MKs treated with a high level of E2.
Conclusion
For the first time, our study demonstrated that a high level of E2 during pregnancy impaired proplatelet formation by activating the intrinsic apoptosis pathway via the Mst1-FoxO1 axis in ITP.
Keyword(s): Immune thrombocytopenia (ITP), Pregnancy, Thrombopoiesis
Abstract: S298
Type: Oral Presentation
Session title: ITP: from bench to bedside
Background
Immune thrombocytopenia (ITP) affects 1-10 in 10000 pregnancies. Although most patients were remaining relatively stable throughout pregnancy, the platelet counts may decrease following the prolongation of gestation, especially in the third trimester. The pathogenesis is usually considered to be secondary to physiologic changes during gestation, such as an increase in blood volume, platelet activation, or increased platelet clearance. However, the precise pathogenesis of ITP during pregnancy has not been fully understood.
Aims
It is to explore the relationship between the high level of estradiol (E2) and defective thrombopoiesis in ITP during pregnancy.
Methods
Twenty consecutive successful pregnancies in 20 ITP patients were studied. Blood samples were analyzed to determine the concentration of E2 at different gestational ages using ELISA. BM-derived CD34+ cells from healthy controls (HCs), ITP patients and pregnant ITP (P-ITP) patients were cultured. BM-derived CD34+ cells from ITP patients were treated with different concentrations of E2. he differentiation of megakaryocytes (MKs) and polyploidization were assessed by flow cytometry. Proplatelet formation (PPF) were observed with a phase-contrast microscope and a confocal microscope. MK apoptosis and markers of apoptosis pathways were detected via flow cytometry, and western blotting was used to evaluated the expression of FoxO1 and Mst1.
Results
P-ITP patients experienced significant reduction in platelet counts during gestation, particularly in the late stages. BM-derived CD34+ cells from HCs, ITP patients and P-ITP patients were sorted and cultured. It was observed that the percentage of CD41+CD42b+ MKs and high ploidy MKs were significantly lower in ITP patients than in HCs. In addition, few MKs with proplatelets were observed in ITP patients. A higher percentage of CD41+CD42b+ MKs and high ploidy MKs were found in P-ITP samples than in ITP samples. However, in P-ITP samples, fewer MKs with proplatelets were observed. The results indicated that the thrombopoiesis ability differed between ITP and P-ITP patients.
The concentration of E2 was founded to be sharply increased during pregnancy in ITP. To explore whether there is a link between the levels of E2 during gestation and thrombopoiesis in ITP patients during pregnancy, BM-derived CD34+ cells from ITP patients were treated with different concentrations of E2, which were determined by the serum levels of P-ITP patients. E2 was observed to dose-dependently promote the MKs differentiation and polyploidization. However, at high E2 levels of 10 nM and 100 nM, few proplatelet-generating MKs were observed. In the 10 nM and 100 nM groups, a high percentage of apoptotic MKs was detected. The physiologic concentration of 0.1 nM had no obvious influence on MKs apoptosis. The expression of Bak, Bax, and cleaved caspase-3, which were components of the intrinsic apoptosis pathway, were significantly increased in the 10 nM and 100 nM groups. Increased apoptotic MKs were also observed in BM biopsy samples from P-ITP patients. These findings indicated that a high concentration of E2 could induced activation of the intrinsic apoptosis pathway in ITP MKs and impaired PPF. The activation of the Mst1-FoxO1 axis, which induced activation of the intrinsic apoptosis pathway, was found in ITP MKs treated with a high level of E2.
Conclusion
For the first time, our study demonstrated that a high level of E2 during pregnancy impaired proplatelet formation by activating the intrinsic apoptosis pathway via the Mst1-FoxO1 axis in ITP.
Keyword(s): Immune thrombocytopenia (ITP), Pregnancy, Thrombopoiesis