HEMATOPOIESIS, HEMOPOIESIS, HEMOPOIETIC

Hematopoiesis
from pluripotent stem cells to
mature, differentiated,
cellular effectors of immunity
and more

BELAJAR BAGAN DAN ALUR HEMATOPOIESIS DENGAN MUDAH

Long-Term Bovine Hematopoietic Engraftment with Clone-Derived Stem Cells
ROBERT LANZA,1 J.-H. SHIEH,2 PETER J. WETTSTEIN,3 RAYMOND W. SWEENEY,4
KAIDA WU,2 ANAT WEISZ,2 NANCY BORSON,3 BOYD HENDERSON,5
MICHAEL D. WEST,1 and MALCOLM A.S. MOORE2

Eckho Mhs Fapet

Fisiologi Ternak, Hemopoiesis, hemopoietic

Anatomy and Physiology of Hemopoiesis

The Bare Essentials

(what you really need to know)

1. All blood cells originate from pluripotent stem cells which reside in the bone marrow and circulate in the blood

2. The pluripotent stem cell differentiates (commits) into two lineages in the bone marrow: the myeloid lineage and the lymphoid lineage

3. The myeloid lineage gives rise to all myeloid cells – erythrocytes, granulocytes (neutrophils, eosinophils, basophils), monocytes and platelets

4. The lymphoid stem cell is generated in the bone marrow: thereafter, development of T and B-cells involves the marrow, thymus, and peripheral lymphoid organs

5. Hematological neoplasms may affect the pluripotent stem cell or any of its committed progeny

Stem cells may be harvested from the blood or marrow and used to treat patients

1. Stem Cells

1. Stem Cells must exist

Adult humans produce about 2 x 10¹¹ erythrocytes (lifespan 100 days), 2 x 10¹¹ neutrophils (lifespan 6 h in circulation) and 2 x 10¹¹ platelets (lifespan 7 days) from the bone marrow daily. Mature blood cells are incapable of division, so this output must arise from precursor cells, otherwise known as progenitor or stem cells. Stem cells have not been visually identified. Their existence is a logical necessity, and can be inferred from various functional assay systems.

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

Definitions

A ‘stem cell’ is a cell capable of both self-renewal and differentiation.

A ‘pluripotent’ hemopoietic stem cell can give rise to cells of all hemopoietic lineages i.e. myeloid cells and lymphoid cells.

A ‘committed’ stem cell has a capability restricted to one or more lineages.

‘Myeloid’ cells are erythrocytes, granulocytes (neutrophils, eosinophils, basophils), megakaryocytes, and macrophages.

‘Lymphoid’ cells are T and B lymphocytes and NK cells.

Stem Cell Hierarchy

Small numbers of pluripotent stem cells give rise to larger numbers of stem cells with ever-increasing lineage commitment

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