Research progress of methodological techniques of generation of platelets from induced pluripotent stem cells in vitro / 中国输血杂志

Platelets play a role in hemostasis in vivo, and platelet transfusion is the main means to treat bleeding diseases caused by thrombocytopenia or platelet dysfunction. However, platelets are in short supply due to the increasing demand for platelet products in clinical, the limited number of blood donors and the disadvantages of platelet products such as short shelf life and bacteria contamination. Currently, induced pluripotent stem cells are considered an ideal source for producing platelets in vitro. They have the potential for self-renewal and differentiation into any cell type, and can be obtained and manipulated easily. Given the recent advances in megakaryocytic series, bioreactors, feeder-free cell production and large-scale propagation research, platelet preparations derived from induced pluripotent stem cells have gradually shown great potential for clinical applications. Considering the minimal risk of alloimmunization and tumorigenesis with these blood products, they are promising to become the standard source of future blood transfusions. This paper reviews the research progress of the methodological techniques of in vitro generation of platelets from induced pluripotent stem cells.

Research Progress on the Mechanism of Tubulin in Megakaryopoiesis and Regulation of Platelet Count--Review / 中国实验血液学杂志

Tubulin affects platelets count through the control of mitosis and the formation of pro-platelets during the maturation of megakaryoblast to platelets. Tubulin is involved in maintaining the integrity of platelet skeleton, and also participates in the change of platelet morphology during platelet activation. Some new anti-tumor drugs targeting cell mitosis are trying to reduce the effect on tubulin in order to reduce the side effect of drugs on platelet formation. In some patients with thrombocytopenia, the variation and polymorphism of the tubulin gene affect the structure of microtubule multimers, which leads to the decrease of platelet formation. This review summarized the latest progresses of tubulin in the regulation of megakaryopoiesis and thrombopoiesis.

Abivertinib inhibits megakaryocyte differentiation and platelet biogenesis / 医学前沿

Abivertinib, a third-generation tyrosine kinase inhibitor, is originally designed to target epidermal growth factor receptor (EGFR)-activating mutations. Previous studies have shown that abivertinib has promising antitumor activity and a well-tolerated safety profile in patients with non-small-cell lung cancer. However, abivertinib also exhibited high inhibitory activity against Bruton's tyrosine kinase and Janus kinase 3. Given that these kinases play some roles in the progression of megakaryopoiesis, we speculate that abivertinib can affect megakaryocyte (MK) differentiation and platelet biogenesis. We treated cord blood CD34+ hematopoietic stem cells, Meg-01 cells, and C57BL/6 mice with abivertinib and observed megakaryopoiesis to determine the biological effect of abivertinib on MK differentiation and platelet biogenesis. Our in vitro results showed that abivertinib impaired the CFU-MK formation, proliferation of CD34+ HSC-derived MK progenitor cells, and differentiation and functions of MKs and inhibited Meg-01-derived MK differentiation. These results suggested that megakaryopoiesis was inhibited by abivertinib. We also demonstrated in vivo that abivertinib decreased the number of MKs in bone marrow and platelet counts in mice, which suggested that thrombopoiesis was also inhibited. Thus, these preclinical data collectively suggested that abivertinib could inhibit MK differentiation and platelet biogenesis and might be an agent for thrombocythemia.

Trastornos plaquetarios hereditarios poco frecuentes: patología molecular y aspectos diagnósticos / Infrequent hereditary platelets disorders: molecular pathology and diagnostic aspects

Introducción: Las plaquetas tienen una función clave en la hemostasia primaria a través de cuatro mecanismos fundamentales: adhesión, agregación, secreción y actividad procoagulante, todos controlados genéticamente por más de 50 genes asociados que han sido identificados. Las manifestaciones clínicas en las alteraciones hereditarias de las plaquetas suelen ser variables; aunque estas alteraciones de la coagulación suelen presentarse con una trombocitopenia notoria, también pueden exhibir trombocitopatías, en las cuales la capacidad hemostática de las plaquetas resulta afectada sin variar su número. Por tanto, existen gran variedad de manifestaciones fenotípicas y mutaciones en relación con la función plaquetaria, algunas de las cuales se explicarán más adelante. Objetivo: Realizar revisión práctica sobre mutaciones plaquetarias hereditarias de baja incidencia y destacar la importancia de su conocimiento, correcto diagnóstico, y tratamiento precoz. Métodos: Se realizó revisión literaria en inglés y españolen MEDLINE, EMBASE, Lilacs y ScienceDirect desde mayo 2019 hasta abril 2020, con el uso de combinación de palabras clave y términos MeSH relacionados con trombastenia, genética médica, hemostasis, agregación plaquetaria, trombopoyesis. Se efectuó análisis y resumen de la bibliografía revisada. Conclusión: Entre las alteraciones hereditarias de las plaquetas se pueden encontrar defectos en todos los mecanismos en que participan; sin embargo, la confirmación diagnóstica sigue siendo complicada por el tiempo y el costo que representa lo que ocasiona diagnósticos inadecuados que impactan en el manejo clínico y la evolución(AU)

Introduction: Platelets have a key role in primary hemostasis through four main mechanisms: adhesion, aggregation, secretion and procoagulant activity, all of these controlled by over 50 associated genes that have been identified. Clinical signs of hereditary platelets alterations are usually variable; even though these disorders of hemostasis generally course with a notorious thrombocytopenia, they also might have thrombocytopathies, in which the hemostatic capacity of platelets is affected without altering its number. According to this, there's a great variety of phenotypic manifestations and mutations that affect platelet function, some of these will be explained later on. Objective: To make a practical review of hereditary platelets mutations that have low incidence in population and to highlight the importance of knowing about them, how to diagnose them and early treatment. Methods: A review of literature in both Spanish and English, was done based on MEDLINE, EMBASE, Lilacs and ScienceDirect, during May 2019 and April 2020 using key words and MeSH terms such as thrombasthenia, medical genetics, hemostasis, platelets aggregation, thromopoiesis. Then, an analysis and summary of the reviewed bibliography was carried out. Conclusion: Among the hereditary alterations of platelets, many defects can be found in every mechanism involved; however, diagnostic confirmation is still complicated due to time and cost, causing inaccurate diagnoses that impact on clinic management and evolution(AU)

Evaluation of efficacy of immunosuppressive therapy plus recombinant human thrombopoietin for children with severe aplastic anemia / 中华儿科杂志

Objective@#To evaluate the therapeutic efficacy and safety of immunosuppressive therapy (IST) combined with recombinant human thrombopoietin (rhTPO) for severe aplastic anemia (SAA) in pediatric patients.@*Method@#A retrospective case-control study was conducted and the clinical data of 45 pediatric patients with de novo SAA admitted to the Anemia Diagnosis and Treatment Center of Chinese Academy of Medical Sciences & Blood Disease Hospital during the period from December 2009 to December 2014 were analyzed. Among them, 15 patients were treated with the regimen of IST together with rhTPO and 30 patients were given IST treatment only. The variation characteristics of the peripheral blood routine as well as the transfusion of blood products was dynamically observed, and the therapeutic efficacy was assessed respectively after 3, 6 and 12 months after the treatment. In the meantime, adverse effects related to rhTPO application were recorded. Thereafter, the statistics of the two groups were compared by non-parametric rank sum test.@*Result@#Among 45 pediatric patients, there were 26 male and 19 female, and the median age was 11 years (6-14). The number of patients received good hematological response(complete remission (CR) plus good partial response (GPR)) in the combinatory group versus vs. the IST group was 6 vs. 3 patients (χ2=3.906, P=0.048) at the 3rd month, 7 vs. 7 patients (χ2=1.568, P=0.210) at the 6th month, and 13 vs. 14 patients (χ2=6.667, P=0.01) at the 12th month respectively. For those achieved good hematological response at the 3rd month, the amount of platelets transfusion and red blood cells transfusion of the combined group were both less than that of the IST group during the period from the 10th to the 12th weeks (platelets transfusion: 1.4 U vs. 2.9 U, t=-3.523, P=0.002; red blood cells transfusion: 0.8 U vs. 2.6 U, t=-2.392, P=0.026). No serious adverse effect related to rhTPO application was observed in the IST combined with rhTPO group.@*Conclusion@#Application of rhTPO can improve the short-term therapeutic efficacy of IST for pediatric SAA, alleviate transfusion dependence, and has a good safety profile.

Así comienza la vida plaquetaria: un viaje desde los megacariocitos medulares a las plaquetas circulantes / The birth of a platelet: A trip from bone marrow megakaryocytes to circulating platelets / Começa assim a vida plaquetária: uma viagem desde os megacariócitos medulares às plaquetas circulantes

Tal vez por haber sido consideradas como simples restos citoplasmáticos de los megacariocitos encargadas únicamente de la reparación de heridas, las plaquetas han tenido un lugar secundario en cuanto a su estudio e interés en comparación con los otros componentes celulares de la sangre. Sin embargo, en los últimos 20 años se ha avanzado mucho en el conocimiento de estas fascinantes células que de a poco han recobrado un lugar destacado dentro de la hematología. A lo largo de este trabajo se han revisado los aportes más destacados y novedosos acerca del proceso de biogénesis plaquetaria, su regulación por el microambiente medular y factores humorales, recorriendo desde la generación de megacariocitos hasta la liberación de plaquetas libres.

Perhaps for being considered mere megakaryocyte cytoplasmic debris responsible for wound repair alone, platelets have had a secondary role when compared to other cellular blood components. However, in the last 20 years we have learned much more about these fascinating cells, which have slowly regained a prominent place in hematology. This review discusses the most outstanding and novel contributions on platelet biogenesis, its regulation by the bone marrow microenvironment and humoral factors, analyzing from megakaryocyte generation to platelet release.

Talvez por ter sido considerados simples restos citoplasmáticos dos megacariócitos, encarregadas apenas da reparação de feridas, as plaquetas têm tido um lugar secundário quanto a seu estudo e interesse em comparação com os outros componentes celulares do sangue. Entretanto, nos últimos 20 anos foi possível aprender muito a respeito destas fascinantes células que aos poucos foram recobrando um lugar de destaque dentro da hematologia. Ao longo deste trabalho foram revistas as contribuições mais destacadas e novas acerca do processo de biogênese plaquetária, sua regulação pelo microambiente medular e fatores humorais, percorrendo desde a geração de megacariócitos até a liberação de plaquetas livres.

Las trombopoyetinas en el tratamiento de la púrpura trombocitopénica inmunitaria y otras trombocitopenias / Thrombopoietines in the treatment of the thrombocytopenic purpura and other thrombocytopenics

La purpura trombocitopénica inmunitaria y las trombocitopenias secundarias representan condiciones patológicas graves cuyo tratamiento plantea diversos grados de dificultad. La aproximación terapéutica convencional ha sido la administración de esteroides, la esplenectomía y el uso de inmunoglobulina intravenosa u otros tipos de anticuerpos (e.g., anti-D). La mejor comprensión de la fisiología y fisiopatología de la trombopoyesis aunado a los avances en biología molecular ha permitido el desarrollo de una nueva aproximación terapéutica, la aplicación de las trombopoyetinas sintéticas o no inmunogénicas. Dentro de este grupo resaltan dos compuestos: el romiplostin (una proteína de fusión) y el eltrombopag (un compuesto sintético de bajo peso molecular). Ambas se encuentran disponibles comercialmente. Los estudios clínicos indican que estos medicamentos tienen un efecto satisfactorio en el tratamiento de las trombocitopenias, particularmente en los casos refractarios a los tratamientos convencionales.

Immune thrombocytopenic purpura and the secondary thrombocytopenias are conditions potentially severe with diverse degrees of treatment difficulties. Steroids administration, splenectomy and the use of intravenous immunoglobulin and other antibodies (e.g., anti-D) had been the conventional therapy. The better understanding of the thrombopoiesis physiology and physiopathology togetter with the biology advances have permitted the development of a new terapheutic approach: the use of synthetic or nonimmunogenic thrombopoietines. Among this group highlights composites: romiplostim (a fusion protein) and eltrombopag (a synthetic composite with low molecular wheigt). Both are already available and produce a satisfactory effect particularly in nonrespondent cases to the conventional treatment.

Does Carica papaya leaf-extract increase the platelet count? An experimental study in a murine model

Objective:To investigate the potential role of fresh Carica papaya (C. papaya) leaf extract on haematological and biochemical parameters and toxicological changes in a murine model. Methods: In total 36 mice were used for the trial. Fresh C. papaya leaf extract [0.2 mL (2 g)/mouse] was given only to the test group (18 mice). General behavior, clinical signs and feeding patterns were recorded. Blood and tissue samples were collected at intervals. Haematological parameters including platelet, red blood cell (RBC), white blood cell (WBC), packed cell volume (PCV), serum biochemistry including serum creatinine, serum glutamic-oxaloacetic transaminase (SGOT) and serum glutamic-pyruvic transaminase (SGPT) were determined. Organs for possible histopathological changes were examined. Results: Neither group exhibited alteration of behavior or reduction in food and water intake. Similarly, no significant changes in SGOT, SGPT and serum creatinine levels were detected in the test group. Histopathological organ changes were not observed in either group of mice except in three liver samples of the test group which had a mild focal necrosis. The platelet count (11.33±0.35)í105/μL (P=0.000 04) and the RBC count (7.97±0.61)í106/μL (P=0.000 03) were significantly increased in the test group compared to that of the controls. However, WBC count and PCV (%) values were not changed significantly in the test group. The platelet count in the test group started to increase significantly from Day 3 (3.4±0.18í105/μL), reaching almost a fourfold higher at Day 21 (11.3í105/μL), while it was 3.8í105/μL and 5.5í105/μL at Day 3 and Day 21 respectively in the control. Likewise, the RBC count in the test group increased from 6í106/μL to 9í106/ μL at Day 21 while it remained near constant in the control group (6í106/μL). Conclusions: Fresh C. papaya leaf extract significantly increased the platelet and RBC counts in the test group as compared to controls. Therefore, it is very important to identify those chemicals of C. papaya leaves as it can be recommended to be used as a medication to boost thrombopoiesis and erythropoiesis in humans and in animals in which these cell lineages have been compromised.

Measurement of immature platelet fraction using the automatic hematology analyzer and its clinical utility / 中华检验医学杂志

Objective The immature platelet fraction (IPF) could be detected quantificationally in Sysmex XE-2100 with the software of XE-pro and IPF master.The study aimed to perform the methodological evaluation of IPF detection and investigate the clinical significance for the monitoring for bone marrow hyperplasia in cancer chemotherapy patients.Methods The high-level, middle-level and low-level whole blood samples were randomly chosen for detection repeatly 20 times to obtain interrun coefficient of variation (CV) for evaluation of the precision and reproducibility. Integrated quality controls were determined for continuous 20 days to obtain intrarun CV, and the stability and carryover was investigated.Furthermore, the correlation between results from Sysmex XE-2100 and results from flow cytometry was assessed.182 healthy subjects and 130 cancer patients undergoing chemotherapy were selected and the latter were divided into two groups according to platelet counts after therapy, one was normal PLT group, the other was decreased PLT group.The IPF of either group was measured and was compared with each other.Results The precision of IPF for high-level, middle-level and low-level were 4.71%, 4.33% and 4.95%, respectively, they were less than 5%.The interrun CV of IPF detection for middle-level and low-level were less than 5%.The interrun CV of IPF detection for high-level were less than 10%.The carryover ranged from 0.6% to 2.7%,and the average rate was 1.2%.A good correlation for IPF detection was shown between results from Sysmex XE-2100 and flow cytometry(r = 0.880 9,P ＜ 0.01).Regarding clinical utility of IPF detection in treatment monitoring for chemotherapy effect, the median of IPF levels in decreased PLT group, normal PLT group,control group were 14.45% ,7.35% and 15.68%, respectively.There was significant difference among the three groups (H =49.032,P ＜0.01 ).The IPF level was higher in decreased PLT group than normal PLT group (t = -5.681, P ＜ 0.O1 ), and was lower in normal PLT group after chemotherapy than the control group (t = -6.662 ,P ＜0.01 ).Conclusions The determination of IPF by the Sysmex XE-2100 owns high precision and good stability. IPF is an effective marker for evaluation of thrombopoietic condition in the cancer chemotherapy patients.