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Updated: Aug 13, 2026
In Situ Exploration of Murine Megakaryopoiesis using Transmission Electron Microscopy
Published on: September 8, 2021
Morphological study on the megakaryocytes with nuclear extrusion and nucleocytoplasmic separation in four cases
Xing-Guo Lu1, Lei Zhu, Wei-Qin Wang
1Department of Hematology, The Second Affilicated Hospital, Medical College, Zhejiang University, Hangzhou 310009, China. Xingguolu@163.com
Abstract:
To investigate the morphological changes of megakaryocytes with nuclear extrusion and nucleocytoplasmic separation, the morphological characteristics of megakaryocytes in peripheral blood films, bone marrow smears, and bone marrow biopsies from 4 newly diagnosed patients with primary myelofibrosis (PMF), myelodysplastic syndrome (MDS), myeloblastic leukemia with maturation (M(2)) and erythroleukemia (M(6)) were studied by using light microscope. The results showed that many kinds of dysmegakaryocytes were observed in bone marrow smears of 4 cases, while in case A (PMF) and case D (M(6)) micromegakaryocytes were ripped apart; in case B (MDS) and case C (M(2)) megakaryocytes were accompanied by nuclear extrusion or nucleocytoplasmic separation, and their bodies were large or giant, the part of nucleus separated from their body and little cytoplasm remained as micromegakaryocytes. The nucleocytoplasmic separation could be displayed by immunocytochemistry stain. It is concluded that the phenomenon of nuclear extrusion and nucleocytoplasmic separation in megakaryocytes suggested the process that dispersed multinuclear releasing towards surround or even totally left the cell body during the megakaryocyte maturation. It also showed that the micromegakaryocytes may be the result of nucleocytoplasmic separation or splittings from multi-separated nucleus.
Insights
Megakaryocyte nuclear extrusion and nucleocytoplasmic separation reveal abnormal maturation processes in blood cancers. These findings suggest micromegakaryocytes may result from nuclear fragmentation during maturation.
Area of Science:
- Hematology
- Cell Biology
- Pathology
Background:
- Megakaryocytes are crucial for platelet production.
- Abnormal megakaryocyte morphology is associated with various hematologic malignancies.
- Understanding megakaryocyte maturation defects is vital for diagnosing and treating blood disorders.
Observation:
- Investigated morphological changes in megakaryocytes from patients with primary myelofibrosis (PMF), myelodysplastic syndrome (MDS), and acute myeloid leukemia subtypes (M2, M6).
- Observed dysmegakaryocytes, including micromegakaryocytes, nuclear extrusion, and nucleocytoplasmic separation in bone marrow samples.
- Immunocytochemistry confirmed nucleocytoplasmic separation, highlighting distinct cellular events.
Findings:
- Nuclear extrusion and nucleocytoplasmic separation were prominent in MDS (M2) and erythroleukemia (M6) cases.
- Micromegakaryocytes were observed, potentially resulting from nuclear fragmentation or separation during maturation.
- Primary myelofibrosis (PMF) and erythroleukemia (M6) showed micromegakaryocytes that appeared ripped apart.
Implications:
- Nuclear extrusion and nucleocytoplasmic separation indicate aberrant megakaryocyte maturation pathways.
- These phenomena may represent a mechanism for multinuclear cell dispersal or fragmentation.
- Micromegakaryocytes could be a consequence of these nuclear separation events, offering insights into disease pathogenesis.
