Hemosiderin

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Histopathology of a case of chronic pulmonary congestion, showing interstitium with hemosiderin deposition (black arrow), edema and collagenous thickening. The alveolus contains a siderophage (white arrow, characterized by coarse brown pigment, which is slightly refractile).
Hemosiderin image of a kidney viewed under a microscope. The brown areas represent hemosiderin

Hemosiderin or haemosiderin is an

lysosomes. The breakdown of heme gives rise to biliverdin and iron.[1][2] The body then traps the released iron and stores it as hemosiderin in tissues.[3] Hemosiderin is also generated from the abnormal metabolic pathway of ferritin.[3]

It is only found within cells (as opposed to circulating in blood) and appears to be a complex of

epithelial cells
of the liver and kidney.

Several disease processes result in deposition of larger amounts of hemosiderin in tissues; although these deposits often cause no symptoms, they can lead to

organ damage
.

Hemosiderin is most commonly found in

organs in various diseases
.

Iron is required by many of the

toxic
when not properly contained. Thus, many methods of iron storage have developed.

Pathophysiology

Hemosiderin often forms after bleeding (haemorrhage).[7] When blood leaves a ruptured blood vessel, the red blood cell dies, and the hemoglobin of the cell is released into the extracellular space. Phagocytic cells (of the mononuclear phagocyte system) called macrophages engulf (phagocytose) the hemoglobin to degrade it, producing hemosiderin and biliverdin. Excessive systemic accumulations of hemosiderin may occur in macrophages in the liver, lungs, spleen, kidneys, lymph nodes, and bone marrow. These accumulations may be caused by excessive red blood cell destruction (haemolysis), excessive iron uptake/hyperferraemia, or decreased iron utilization (e.g., anaemia of copper toxicity) uptake hypoferraemia (which often leads to iron deficiency anemia).

Cellular iron is found as either ferritin or hemosiderin. It is identified in cells by the Perls or Prussian blue reaction, in which ionic iron reacts with acid ferrocyanide to impart a blue color.<Wintrobe's Clinical Hematology>

Diseases associated with hemosiderin deposition

Main article: Hemosiderosis

Hemosiderin may deposit in diseases associated with iron overload.

sickle cell anemia and thalassemia
.

References

  1. ^ "Hemosiderin". Definition, Staining, Function and Treatment. 2019-05-04. Retrieved 2019-05-04.
  2. PMID 29261920
    . Retrieved 2019-05-04.
  3. ^
    S2CID 90250940
    .
  4. PMID 13449232
    .
  5. PMID 5136270
    .
  6. ISBN 978-1-4557-2613-4.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  7. ^ "Forensic Pathology".
  8. ^ "Hereditary haemochromatosis through 150 years". Tidsskrift for den Norske Legeforening. Retrieved 2018-07-14.
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