Establishment of a platelet production model by bone marrow cavity transplantation of mouse primary megakaryocytes / 中华血液学杂志

Objective: To establish an intramedullary transplantation model of primary megakaryocytes to evaluate the platelet-producing capacity of megakaryocytes and explore the underlying regulatory mechanisms. Methods: Donor megakaryocytes from GFP-transgenic mice bone marrow were enriched by magnetic beads. The platelet-producing model was established by intramedullary injection to recipient mice that underwent half-lethal dose irradiation 1 week in advance. Donor-derived megakaryocytes and platelets were detected by immunofluorescence staining and flow cytometry. Results: The proportion of megakaryocytes in the enriched sample for transplantation was 40 to 50 times higher than that in conventional bone marrow. After intramedullary transplantation, donor-derived megakaryocytes successfully implanted in the medullary cavity of the recipient and produce platelets, which showed similar expression of surface markers and morphology to recipient-derived platelets. Conclusion: We successfully established an in vivo platelet-producing model of primary megakaryocytes using magnetic-bead enrichment and intramedullary injection, which objectively reflects the platelet-producing capacity of megakaryocytes in the bone marrow.

Utilidad diagnóstica de la biopsia de médula ósea en pediatría / Diagnostic utility of biopsy of bone marrow in Pediatry

La biopsia de médula ósea (BMO) es un procedimiento invasivo que ha ganado campo en la práctica médica ya que se realiza para el diagnóstico, estadificación y seguimiento de enfermedades hematológicas y no hematológicas, benignas o neoplásicas, entre otros. El objetivo fue establecer el rol de la BMO en las hemopatías en Pediatría en el ION SOLCA Guayaquil- Ecuador. Se utilizó un estudio descriptivo retrospectivo donde se incluyeron a todos los pacientes pediátricos menores de 18 años de edad que se sometieron a BMO, desde Julio de 2014 a Julio de 2017 en el hospital. De las 1511 BMO realizadas en el periodo de estudio, 869 correspondieron a biopsias pediátricas, de las cuales el 57,08% fueron varones. La edad mediana fue 5 (RIC: 3-10) años. El tamaño promedio de la BMO fue de 0,74 (0,1-2,5) cm, con una celularidad media de 20% (4-100%). El motivo de consulta más frecuente fue la fiebre (22,67%). En el hemograma se detectó más frecuentemente bicitopenia (44,65%) y pancitopenia (24,63%). La Leucemia Linfoblástica Aguda (LLA) fue la enfermedad hematológica maligna más comúnmente encontrada (19,59%). Solo un 0,12% correspondió al grupo de Síndromes Mielodisplásicos (SMD), mientras que un 0,23% fueron Neoplasias Mieloproliferativas (NMP). El 26,93% de las biopsias no fueron aptas para el diagnóstico, el 48,45% se encontraron libres de enfermedad de base. La enfermedad oncohematológica pediátrica más frecuente es la LLA, mientras que los SMD y las NMP son infrecuentes. El rol del patólogo y de la BMO es fundamental en el diagnóstico de las enfermedades hematológicas, siempre en integración con la clínica y los exámenes complementarios.

Bone marrow biopsy (BMB) is an invasive procedure that has gained ground in medical practice since it is performed for the diagnosis, staging and monitoring of hematological and non-hematological, benign or neoplastic diseases, among others. This work aims to establish the role of the BMB in hematological diseases in Pediatrics in the ION SOLCA Guayaquil ­ Ecuador. A non-experimental design study, descriptive type was used, that included all pediatric patients under 18 years of age who submitted a BMB, from July 2014 to July 2017 in the hospital. Of the 1511 BMB performed in the study period, 869 corresponded to pediatric biopsies, of which 57.08% belong to male patients. The median age was 5 (interquartile range: 3 - 10) years. The average size of the BMB was 0.74 (0.1 - 2.5) cm, with an average cellularity of 20% (4 - 100%). The most frequent reason for consultation was fever (22.67%). In the complete blood count, bicytopenia (44.65%) and pancytopenia (24.63%) were detected most commonly. Acute Lymphoblastic Leukemia (ALL) was the most frequent malignant hematologic disease (19.59%). Only 0.12% corresponded to the group of Myelodysplastic Syndromes (MDS), while 0.23% were Myeloproliferative Neoplasms (MPN). 26.93% of the biopsies were not apt for diagnosis, 48.45% were free of base disease. The most cfrequent pediatric onco-hematologic disease is ALL, while MDS and MPN are infrequent. The role of the pathologist and the BMP is fundamental in the diagnosis of hematological diseases, always in integration with the clinic and complementary examinations.

Attenuated form of Evans syndrome among pediatric ITP patients.

Long term follow up of adult patients with immune thrombocytopenic purpura (ITP) have shown evolvement of secondary autoimmune diseases such as SLE, Evans syndrome, autoimmune neutropenia, Graves disease etc. We studied 30 cases of pediatric ITP patients for evidence of hemolysis to assess the possibility of Evans like syndrome. Measurement of free serum haptoglobin, a sensitive indicator of red cell destruction was used after careful exclusion of micro angiopathic hemolysis, SLE or overt Evans Syndrome. Results showed abnormally low level of free serum haptoglobin in 11 of the 30 (36.7%) patients compared to that in 20 age matched controls (P < 0.001) as an evidence of hemolysis. Our data in pediatric patients is similar to that reported in adult ITP cases and support the observation of Evans made 50 years ago that there is a spectrum like relationship between primary thrombocytopenia and hemolytic anemia. Thus the concept of attenuated form of Evans syndrome could be considered, in group of patients with ITP in pediatric age group.

Comparison of oligonucleotide-microarray and serial analysis of gene expression (SAGE) in transcript profiling analysis of megakaryocytes derived from CD34+ cells

For the comprehensive analysis of transcript expression, the array-based hybridization analysis and the serial analysis of gene expression (SAGE) are commonly used platforms. The SAGE is based on a high-throughput sequencing of ditags derived from the transcript. DNA microarrays are a powerful tool for monitoring thousands of transcripts simultaneously, whereas the Genechip (Affimatrix microarray) technology is based on the hybridization of a single probe or other manufacturer's microarrays (cDNA- or oligonucleotide-microarray) procedures include the competitive hybridization of two probes. In this study, the quantitative accuracy of expression using oligonucleotide-microarray was determined by comparing data set from the SAGE. In previous study the microSAGE was performed for the megakaryocytes and non- megakaryocytes derived from human cord blood CD34(+)cells by ex vivo expansion using thrombopoietin, and a total of 38,909 tags representing 8,976 unique genes were obtained. On the identical RNA, expression profiling was also carried out using oligonucleotide-microarray (MAGIC II 10K chip, Macrogen). The most frequently expressed genes in human megakaryocytes were identified as platelet factor 1 followed by annexin A1, ribosomal protein S23. The majority of the 50 most highly expressed genes in the CD34(+)-derived megakaryocytes were those involved in protein synthesis, e.g., ribosomal proteins. The expression level through the single channel of oligonucleotide-microarray and SAGE have a fairly good correlation in terms of absolute analyses and that the correlation is higher for the genes with higher expression levels.