Iron kinetics

Question 1

% of inorganic Iron is absorbed

Answer 1

10%

Question 2

Entry of non-heme iron?

Answer 2

1. DcytB (Duodenal cytochrome B): Ferroreductase

2. DMT1 (Divalent Metal Transporter)

Question 3

Entry of heme iron

Answer 3

HCP1

Question 4

Where is iron absorbed?

Answer 4

Enterocyte

Epithelial cells

Question 5

What protein converts Ferrous to Ferric for transport in blood?

Answer 5

Hephaestin

Question 6

What type of iron can be transported in blood?

Answer 6

Ferric (Fe3+)

Question 7

What cells store/transport Iron?

Answer 7

Enterocytes
Hepatocytes
Macrophages

Question 8

How much iron is derived from RBC turnover?

Answer 8

20-25mg/day

Question 9

Form of stored Iron?

Answer 9

Ferritin

Question 10

The transporter of iron across cell membrane

Answer 10

Ferroportin

Question 11

What cells have Transferrin receptor (TfR)?

Answer 11

All cells except RBC

Question 12

How many Iron per transferrin? and what type of Iron?

Answer 12

2 Ferric molecules are transported per transferrin.

Question 13

Mechanism of Iron transport through TfR?

Answer 13

• TfR bind Tf and prompt endocytosis
• pH drops (acidification) and Iron released.
• TfR is recycled to the cell surface

Question 14

What cells have ferritin the most?

Answer 14

Liver
Bone Marrow
Spleen
Reticuloendothelia Macrophage

Question 15

Role of Hepcidin

Answer 15

Degrade ferroportin

no more exported Iron

Question 16

What regulate Hepcidin

Answer 16

Transferrin

Question 17

What type of Iron can be exported through the cell membrane?

Answer 17

Ferrous (Fe2+)

Question 18

Iron distribution in adults

Answer 18

2-3g/female

4g/male

Question 19

Iron daily requirements

Answer 19

1mg for men and postmenopausal women
1.5mg for women in reproductive years
2-3mg for pregnant and lactating women

Question 20

How much iron is drained by menstrual cycle annually?

Answer 20

20-40mg

Question 21

What is SI?

Answer 21

Serum Iron = Iron bound to Transferrin

Question 22

What is TIBC

Answer 22

Total Iron Binding Capacity

All the binding site available on transferrin.

Question 23

What reagent is used to wash the excess Fe3+ in TIBC test?

Answer 23

MgCO3

Question 24

How to calculate the % transferrin saturation

Answer 24

SI/TIBC * 100

Question 25

What is Transferrin?

Answer 25

Plasma protein carrying iron (Fe3+) to developing Erythroid cells.

Question 26

When is Serum Ferritin elevated?

Answer 26

By the Acute Phase Response: 1. Produced by liver during inflammation 2. Sequester by Bacteria

Question 27

What is hemosiderin

Answer 27

Contains hundreds of ferritin as an insoluble complex. | Lost some surface proteins

Question 28

What are difference between Hemosiderin ans Ferritin?

Answer 28

1. Surface proteins Degraded in Hemosiderin 2. Iron concentration Higher in Hemosiderin 3. Release Iron Faster in Ferritin

Question 29

When is Purissan Blue used?

Answer 29

To test stored iron by staining hemosiderin (NOT ferritin)

Question 30

Zinc Protoporphyrin Assay

Answer 30

Detect when Heme syn is inhibited due to the lack of Iron (Zn binds Protoporphyrin IX instead Fe)

Question 31

How is ZPP assay reported?

Answer 31

The assay is reported as Free Erythrocyte Protoporphyrin | OR: ZPP/Heme

Question 32

The elevation of sTfR indicates?

Answer 32

Cells produce more TfR when stored iron is low. The TfR is shed become sTfR in plasma. The elevation of sTfR indicates the low level of stored iron

Question 33

Percentage of Iron in body

Answer 33

70% in Hgb 15-30% in liver and RE 4% Myoglobin 0.1% in plasma transferrin

Question 34

Total body Iron

Answer 34

3-5 g | 1-2mg in flux

Question 35

Stage 1 of Iron Deficiency

Answer 35

Low Iron storage. Hematopoiesis is not affected

Question 36

Stage 2 of Iron Deficiency

Answer 36

Storage Iron is very low | Hematopoiesis is depend of transported Iron

Question 37

Lab test of IDA

Answer 37

``` Low SI Low ferritin Incre TIBC Decre % Tf sat. Low sTfR ```

Question 38

Stage 3 of Iron Deficiency

Answer 38

Depletion of stored and transport Iron

Question 39

Dietary allowance for Iron 14-18 yrs: 19-50 yrs:

Answer 39

14-18 yrs: 11-15mg | 19-50 yrs: 8/m - 18/f

Question 40

IDA Oral treatment

Answer 40

325mg FeSO4 (1-3 tablets/day) = 30-60 mg

Question 41

Disadvantage of Oral treatment

Answer 41

GI side effect Slow (4-6 weeks) Fail during treatment

Question 42

IDA Parental treatment

Answer 42

4 units of RBC (1000mg IV) -> Hgb points increase 4.

Question 43

Where is Lactoferrin

Answer 43

In Neutrophils

Question 44

Lab test for Anemia of Chronic Inflammation

Answer 44

Low SI Decr TIBC Normal or low % saturated Tf High serum Ferritin

Question 45

Sideroblastic Anemia

Answer 45

Deficiency protoporphyrin synthesis

Question 46

How is BM in Sideroblast Anemia

Answer 46

Abundant of Iron | Iron in Normoblast waiting for Heme syns.

Question 47

Enzyme is affected in CEP

Answer 47

Uroporphyrinogen Synthase III

Question 48

Enzyme is affected in EPP

Answer 48

Ferrochelatase

Question 49

Congenital Erythropoietic Porphyria

Answer 49

Autosomal Recessive

Question 50

Erythropoietic Protoporphyria

Answer 50

Autosomal Dominant

Question 51

How lead interferes Heme synthesis?

Answer 51

Block ALA to PBG | Block Fe bind to Protoporphyrin IX

Question 52

Lab test for Sideroblastic Anemia

Answer 52

``` High Iron in BM High SI High % transferrin saturation Normal TIBC High serum Ferritin ```

Question 53

Overload Iron

Answer 53

Hemochromatosis

Question 54

What gene get mutated in Hemochromatosis?

Answer 54

HFE gene - Lack of Hepcidin - Constitutive absorption of Iron - Absorb 4mg Iron daily

Question 55

Lab test of Hemochromatosis

Answer 55

High SI High % Tf sat. Low TIBC High serum Ferritin