Iron metabolism &Iron deficiency anemia

Abbas A. A. Shawka

Overview • Introduction• Distribution of iron• Iron metabolism• Iron overload • Iron deficiency anemia

Introduction ( trace elements )

• in biochemistry, a trace element is a dietary element that is needed in very minute quantities for the proper growth, development, and physiology of the organism. For example, magnesium is a trace metal.

• So, when we talk about Iron, you should know that we are talking about a trace element, for more specific, Iron is the most important trace element.

Trace elements

Why our body need Iron ?

Sources if Iron

• Heme Iron That found in animal sources , and it is much better to be absorbed in the bowel than non-heme Iron

• Non-Heme Iron It is less aborbed by bowel

Sources of Iron

• Your body needs iron to make hemoglobin, found in red blood cells, and myoglobin, found in muscles.

• The best sources of iron are found in lean beef, eggs, salmon, tuna, liver, oysters, poultry (dark meat), dried fruits and beans, and whole grains.

• Smaller amounts of iron can also be found in almonds and brazil nuts, as well as dark leafy greens, such as spinach, kale, collard and dandelion greens.

• However, it is harder for your body to absorb iron from vegetables, nuts, dried fruit, and whole grains.

• By pairing them with meat or fish, your body will be better able to get the full benefit of the iron vegetables, nuts, and whole grains contain.

Iron metabolism

• Most Iron in the food that we ingested is in the ferric form ( Fe+3 ) but Iron can only be resorbed by the bowel in bivalent form (i. e., as Fe2+).

• For this reason, reducing agents in food such as ascorbate (vitamin C ) promote iron uptake.

• In this case, when we ingest heme iron it will be absorbed quickly because of appearance of Hemoglobin Carrier Protein ( HCP ) in the apical part of enterocyte

• In case of ingest non- heme iron , firstly it should be transfer from Fe+3 to Fe+2 by reductase agent ( ascorbic acid or ferric reductase Dcytb1 ) , after that it will be transport to inside the enterocyte by divalent material transport ( Dmt1 ).

• Iron enter the enterocyte1- some will be storage in the enterocyte as ferritin.2- some will transport through the basolateral surface of enterocyte by ferroprotein.

• Hephaestin is membrane bound- ferri oxidase enzyme, which contain copper, converts Fe2+ to Fe3+ at the basal surface prior to binding apotransferrin.

• Hepicidin controls iron body status by affecting ferroportin-1 concentration.

• Ceruloplasmin- circulated ferri oxidase (copper containing protein), convert Fe+2 into Fe+3 in circulation for binding apotransferrin.

Storage form of Iron in body

• Transferrin ( protein carrier ) of Iron in the circulation• Apotransferrin ( transferrin not bind to Iron ) • Ferritin ( storage form of Iron in the hepatocytes and

enterocytes.

Note : Iron is absorbed specifically in the duodenum

Iron overload

• Disturbances resulting from raised iron concentrations are less frequent. Known as hemochromatoses, these conditions can have genetic causes, or may be due to repeated administration of blood transfusions. As the body has practically no means of excreting iron, more and more stored iron is deposited in the organs over time in patients with untreated hemochromatosis, ultimately leading to severe disturbances of organ function.

Methods for investigating Iron deficiency in the blood

1) Serum ferritin2) Transferrin saturation index 3) Total Iron binding capacity ( TIBC ) 4) Serum Iron concentration

Why Iron deficiency cause anemia ?

• Because Iron is one of the main components of the Heme and the heme is the main components of RBCs wich its main function is to gas exchange.

Signs and symptomes of anemia

The hand of a person with severe anemia compared to one without

Human blood from a case of iron deficiency anemia (Giemsa stain)

Iron deficiency anemia

Microcytic hypochromic red blood cells• Disturbances of the iron metabolism are frequent and

can lead to severe disease pictures. Iron deficiency is usually due to blood loss, or more rarely to inadequate iron uptake. During pregnancy, increased demand can also cause iron deficiency states. In severe cases, reduced hemoglobin synthesis can lead to anemia (“iron-deficiency anemia”). In these patients, the erythrocytes are smaller and have less hemoglobin. As theirmembrane is also altered, they are prematurely eliminated in the spleen.

Further causes of anemia

Diagnosing of Iron deficiency anemia

• Laboratory findings 1- Haematological Investigations(1) Hemoglobin level ( decrease ) RBCs count ( decrease ) MCV mean corpuscular volume and MCH mean corpuscular hemoglobin

( decrease ) Hypochromia Platelets (usually thrombocytosis) ( increase )

2- Biochemical Laboratory findings (2) Serum ferritin level ( decrease ) Transferrin saturation index ( decrease ) Total iron-binding capacity TIBC ( increase ) Serum iron concentration ( decrease )

• Tests that may be done to look for the cause of iron deficiency:

1. Colonoscopy 2. Fecal occult blood test 3. Upper endoscopy