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Megakaryocyte Differentiation and Platelet Formation from Human Cord Blood-derived CD34+ Cells
Published on: December 27, 2017
Isolation of megakaryocytes from human placentae
M J Woods1, M Greaves, P V Lawford
1Department of Medical Physics and Clinical Engineering, University of Sheffield, Royal Hallamshire Hospital, Glossop Road, Sheffield, S10 2JF, UK.
Abstract:
Shedding of cytoplasm from circulating megakaryocytes (MKs) within the pulmonary vasculature suggests the lungs are an important site for normal platelet production. Fetal lungs receive only a minor fraction of the circulating blood volume. The placenta may act as a site for intrauterine platelet formation. Isolation of MKs from fetal vessels within the placenta has not been previously reported. Immediately after delivery, 3 human placentae were subjected to forward and retrograde perfusion across the placental capillary bed on the fetal side. MKs in perfusates were harvested by 'whole blood filtration' and identified by morphological and immunochemical methods. All perfusates yielded MKs. Qualitatively MKs with copious cytoplasm were more commonly found in perfusates collected from fetal arteries compared with those from fetal veins. This is consistent with filtration of MKs and fragmentation of their cytoplasm within the placental microcirculation to produce platelets. Perfusion of human placentae followed by filtration of perfusates is a useful technique for harvesting fetal MKs and permitting further elucidation of their physiological role.
Insights
The human placenta may be a site for fetal platelet production. Researchers isolated megakaryocytes (MKs) from placental perfusates, suggesting MKs shed cytoplasm to form platelets in fetal circulation.
Area of Science:
- Obstetrics and Gynecology
- Hematology
- Developmental Biology
Background:
- Pulmonary vasculature is a known site for megakaryocyte (MK) cytoplasmic shedding, suggesting lung-based platelet production.
- Fetal lungs receive limited blood flow, prompting investigation into alternative intrauterine sites for platelet formation.
- Intrauterine platelet production by megakaryocytes (MKs) has not been previously studied in the human placenta.
Purpose of the Study:
- To investigate the human placenta as a potential site for fetal platelet production.
- To isolate and characterize megakaryocytes (MKs) from fetal placental vasculature.
- To explore the physiological role of MKs in intrauterine platelet formation.
Main Methods:
- Human placentae were perfused retrogradely and anterogradely via the fetal vasculature immediately post-delivery.
- Megakaryocytes (MKs) were harvested from perfusates using a 'whole blood filtration' method.
- Isolated MKs were identified using morphological and immunochemical analyses.
Main Results:
- Megakaryocytes (MKs) were successfully isolated from all placental perfusates.
- MKs with abundant cytoplasm were more prevalent in perfusates from fetal arteries than veins.
- Findings suggest MKs undergo cytoplasmic fragmentation within the placental microcirculation, consistent with platelet formation.
Conclusions:
- The human placenta serves as a viable site for harvesting fetal megakaryocytes (MKs).
- Evidence supports the placenta's role in intrauterine platelet production through MK cytoplasmic shedding.
- This technique facilitates further research into the physiological functions of fetal MKs.
