Anatomy and Physiology of Hemopoiesis

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Anatomy and Physiology of Hemopoiesis

• John Matthews
• Queens Hematology

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The Bare Essentials

1. All blood cells originate from pluripotent stem
   cells
2. The pluripotent stem cell differentiates
   (commits) into two lineages in the bone marrow
   the myeloid lineage and the lymphoid lineage
3. The myeloid stem cell gives rise to all myeloid
   cells erythrocytes, granulocytes (neutrophils,
   eosinophils, basophils), monocytes and platelets
4. The lymphoid stem cell produces B and
   T-lymphocytes
5. Hematological neoplasms may affect the
   pluripotent stem cell or any of its committed
   progeny
6. Bone marrow can be easily biopsied
7. Stem cells may be harvested from the blood or
   marrow and used to treat patients

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Lifespan and production of blood cells
Cell type Approximate lifespan Production rate cells/day Production rate cells/sec Production rate Kg/year
Red Cells 100 days 2 x 1011 2.3 million 7.3
Neutrophils t½ 6 hours 3 x 1010 350,000 10.9
Platelets 7 days 1 x 1011 1.2 million 4.6
Lymphocytes t½ 10 days 1 x 1010 116,000 3.7
Annual total 26.5 Kg
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Pluripotent stem cells in mice
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Murine pluripotent hemopoietic stem cell
Hemopoietic colonies in the spleens from 3 mice
lethally irradiated and transplanted with
syngeneic bone marrow. Each colony is the progeny
of a single stem cell (CFU-S)
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Stem cells in semi-solid culture
mixed colonies CFU-GEMM
granulocyte/ macrophage colonies CFU-GM
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Human Hemopoiesis
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Control of Hemopoiesis

• Growth Factors e.g. stem cell factor
• Hormones e.g. erythropoietin, thrombopoietin,
  filgrastim
• Sinusoidal epithelium

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Red marrow
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Red marrow trephine biopsy
bone trabecula
blood and fat
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Red marrow trephine biopsy
blood and fat
bone trabecula
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Aspirated Marrow Cells
red cell precursor
white cell precursor
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Assessment of Hemopoiesis

• Blood count
• Reticulocytes
• Marrow examination

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Stem Cell Transplant

• Allogeneic
• Autologous

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stem cell harvest
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stem cell thawing
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stem cell infusion
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Stem Cell Disease States

• Failure of stem cells
• Neoplasia

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Bone marrow biopsy in aplasia
normal
aplastic anemia
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Bone marrow aspirate in acute leukemia
acute leukemia
normal
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Therapeutic use of Growth Factors

• Erythropoietin
• Filgrastim
• Thrombopoietin analogs