Hematopoiesis 2

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Hematopoiesis 2

• September 15, 2006

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Outline

• review first hematopoiesis lecture
• talk about bone marrow aspiration biopsy
• talk about cell stages of hematopoiesis

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Review

• Questions??
• Tell me the adult and fetal sites of
  hematopoiesis
• requirements for hematopoiesis

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Remaining Objectives

• 5. Define the terms ineffective erythropoiesis
  and extramedullary hematopoiesis and give
  examples of their occurrence.
• 6. Discuss reasons for bone marrow examination
  including indications for aspirates and trephine
  biopsies. Calculate and interpret
  myeloiderythroid ratios (ME ratios).
• 7. Recognize, describe and name all stages of
  development of bone marrow and peripheral blood
  cells including erythropoiesis, granulopoiesis,
  and thrombopoiesis.

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Terms to know

• extramedullary hematopoiesis
• formation of blood cells in sites other than
  the bone marrow i.e. liver, spleen,
• why? demand for cells
• erythropoiesis - rbc production
• granulopoiesis - wbc (granulocyte production)
• thrombopoiesis - platelet production
• ineffective hematopoiesis
• inability of the bone marrow to generate a
  reasonable number of blood cells
• multi or pluri potential stem cell
• also called a colony forming cell - the cell
  that gives rise to all blood cells - the most
  immature cell

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Routes a stem cell can take
self-renew

• differentiate

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Hematopoietic Cell Differentiation

• CFU-L pluripotential blast
  colony-forming cell self renew
• lymphocyte
• CFU-GEMM self renew
• BFU-E CFU-GM CFU-Eo CFU-Bas CFU-Meg
• CFU-E CFU-G CFU-M
• erythrocyte neutrophil monocyte eosinophil
  basophil megakaryocyte

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Indications for a Bone Marrow Examination

• Why do we exam bone marrow?
• To provide more information to diagnostic clues
  seen in the peripheral blood
• increase or decreased wbc, rbc or platelets
  presence of abnormal or immature cells

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BM required for the diagnosis of

• some types of anemia
• neutropenia
• leukemia
• suspected megakaryocyte abnormalities
• tumors
• storage diseases
• some infections

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Bone Marrow Examination
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Normal Bone Marrow Aspirate
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Normal Bone Marrow Biopsy
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Erythropoiesis
bone marrow Sinusoidal circulation
wall CFU-E mature
red cell pronormoblast
basophilic normoblast
reticulocyte polychromatic
normoblast orthochromatic normoblast

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Normal RBC Maturation Series

• 1. pronormoblast (rubriblast)
• 2. basophilic normoblast (prorubricyte)
• 3. polychromatic normoblast (rubricyte)
• 4. orthochromatic normoblast (metarubricyte)
• 5. reticulocyte (diffusely basophilic rbc)
• 6. mature erythrocyte

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Nutritional Requirements for Erythropoiesis

• 1. protein and amino acids
• 2. vitamin B12 and folic acid
• 3. vitamin B6 (pyridoxine)
• 4. vitamin C
• 5. iron
• 6. copper
• 7. cobalt

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Granulopoiesis
bone marrow precursors proliferating
mature/storage blood
tissue myeloblast
segmented GM-CFU circulating
31x107/kg band promyelocyte

myelocyte marginating GEMM-CFU
39x107/kg metamyelocyte
1.5x109/kg day-1


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Granulopoiesis Statistics

• takes 8 -12 hours per cycle
• 7 - 11 days
• neutrophils circulate for 6 - 8 hours
• live in tissues 48 hours

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Thrombopoiesis
Bone Marrow Precursors Proliferating
Endoreduplicating Blood
Tissue CFU-Meg 1N 2N
8N 32N
Megakaryoblast
Megakaryocyte CFU-GEMM
Platelets Circulating
and Marginating

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Thrombopoiesis

• endoreduplication - doubling of DNA without the
  cell dividing
• marginating pool for emergencies
• at any given time 30 of platelets are in the
  spleen