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ERYTHROPOIESIS

Dr. Ni Kadek Mulyantari, Sp.PK(K)(Department of Clinical Pathology Medical Faculty Udayana University/Sanglah

General Hospital Denpasar)

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HEMATOPOIESIS

• Hematopoiesis merupakan proses pembuatan sel darah• Berasal dari bahasa yunani haima (darah) dan poiein (membuat).

Rata rata untuk dewasa, sum-sum tulang ~5x1011 sel per hari.

• Sel dari darah dibagi menjadi erythrocytes (red blood cells), leukocytes (white blood cells) berbagai macam, dan platelets.

• Erythrocytes : Erythropoiesis• Leukocytes : Leukopoiesis• Thrombocyte : Thrombopoiesis

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THE LOCATION OF HEMATOPOIESIS

• Hematopoiesis dimulai di yolk sac saat bulan pertama dari embryogenesis tapi secara perlahan berpindah ke hati dan, dengan jumlah lebih sedikit, limfa.• Hati merupakan tempat hematopoiesis saat trimester kedua.• Sum-sum tulang menjadi tempat hemopoiesis utama setelah

bulan ketujuh.• Setelah lahir, sum-sum tulang menjadi tempat satu-satunya

hematopoiesis (intramedullary hematopoiesis). • Hematopoiesis may resume in the liver and spleen after

birth in conditions associated with fibrosis of the bone marrow (extramedullary hematopoiesis).

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NUTRITIONAL REQUIREMENT OF ERYTHROPOIESIS

•Vitamin B12•Folic acid•Vitamin B6•Trace Metals•Iron•Other Vitamins ( Vit C, Vit A, Vit E)

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ERYTHROPOIESIS

•The earliest recognizable RBC precursor is proerythroblast, •The last nucleated RBC precursor is the orthochro- matophilic erythroblast, which is characterized by well-hemoglobinized cytoplasm; the nucleus is then lost, producing the reticulocyte.

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•Reticulocytes are identified using supravital stains such as new methylene blue; BCB• they cannot be definitively identified with routine

Wright-Giemsa stains.•Reticulocytes contain ribonucleic acid (RNA) for 4

days; normally, the first 3 days are spent in the marrow and fourth in the blood. However,under intense stimulation by erythropoietin, reticulocytes may be released into the blood early where they may contain RNA for 2.0 to 2.5 days (shift reticulocytes).

ERITROPOESIS

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The maturation of erythrocytes follows the common pathway of all hematologic cells

•Cell size is reduce•Cytoplasmic RNA production decrease,(in

erythrocyte, hemoglobin starts at the polychromatic normoblast stage and increases until the cell reaches maturity)•The cytoplasma-to-nucleus ratio become greater

(nucleus become smaller)•Nuclear chromatin becomes more aggregated•Nucleoli disappear

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Proerythroblasts

•the earliest, least mature cells in the erythrocyte forming series (erythropoiesis).•Proerythrocytes exist in circulating blood only under pathological conditions (extramedullary hematopoiesis; breakdown of the blood–bone marrow barrier by tumor metastases, erythroleukemia)

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Polychromatic and Orthochromatic Erythroblasts (Normoblasts)

• The results of mitosis of erythroblasts are called normoblasts• Polychromatic and orthochromatic erythroblasts may be released

into the bloodstream whenever hematopoiesis is activated, e.g., in the compensation or treatment stage after hemorrhage or iron or vitamin deficiency. • They are always present when turnover of blood cells is chronically

increased (hemolysis). • the presence of erythroblasts in the blood should prompt

consideration of two other disorders: extramedullary production of blood cells in myeloproliferative diseases and bone marrow carcinosis with destruction of the blood–bone marrow barrier.

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RETICULOCYTE

•Reticulocytes mengandung ribonucleic acid (RNA) •Normal value in peripheral blood 0,5 – 1,5 %•Cell size : Sedikit lebih besar dari sel dewasa(7-9 µ)•Ukuran sel: Bundar

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RETICULOCYTE

•Cytoplasma :fully hemoglobinized; nucleus extruded from cell, leaving a slightly polychromatic red cell when by romanowsky (identified using supravital stains such as new methylene blue; BCB)•↑ : Hemolytic anemia, acute bleeding, th/ anemia•↓: Aplastic anemia, ACD

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ERYTHROCYTES

Cell size : 6,7-7,7 µCell shape : Round

Cytoplasm : Staining: pink, with slightly more intense color at the peripheral and lighter color in the center

Nucleus : not present

ERYTHROCYTES

•Composition :- 60% Air- 28% hemoglobin :

* blood pigmen * sarana transport O2* 96% globin* 4% heme

- 7% Fat- Carbohydrat, Electrolyte, Enzyme, Metabolite

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•Ukuran Erythrocyte 1. Normal (normositer) Aplastic anemia, acute bleeding, hemolytic anemia

2. Micrositer Iron def Anemia, ACD, thalasemia, sideroblastic anemia

3. Macrositer Folic acid & B12 def anemia

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Erythrocyte Form

• Normal : biconcave• Abnormal : ovalocyte, spherocyte, stomatocyte, target cells, ect

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Ovalocyte

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Tear drop cells

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Target cells

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Stomatocyte

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Spherocyte

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Poikilocytosis

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The Erythrocyte colors

•Normal : normochromic :pink(central palor < 1/3 erythrocyte dianmeter)•The erythrocyte color depend on hemoglobin concentration•Hipochromic : central pallor >1/2 erythrocyte dianmeter (low hemoglobin level)

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