Search results
Results from the WOW.Com Content Network
Micrograph showing hemosiderin-laden alveolar macrophages, as seen in a pulmonary hemorrhage. H&E stain. An alveolar macrophage, pulmonary macrophage, (or dust cell) is a type of macrophage, a professional phagocyte, found in the airways and at the level of the alveoli in the lungs, but separated from their walls. [1]
Macrophages are found in essentially all tissues, [4] where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microglia, and others), but all are part of the mononuclear phagocyte system.
They are also called pulmonary macrophages, and dust cells. Alveolar macrophages also play a crucial role in immune responses against viral pathogens in the lungs. [25] They secrete cytokines and chemokines, which recruit and activate other immune cells, initiate type I interferon signaling, and inhibit the nuclear export of viral genomes. [25]
A siderophage is a hemosiderin-containing macrophage. Heart failure cells are siderophages generated in the alveoli of the lungs of people with left heart failure or chronic pulmonary edema, when the high pulmonary blood pressure causes red blood cells to pass through the vascular wall. [1] Siderophages are not specific of heart failure.
Macrophages are diffusely scattered in the connective tissue and in liver (Kupffer cells), spleen and lymph nodes (sinus histiocytes), lungs (alveolar macrophages), and central nervous system (microglia). The half-life of blood monocytes is about 1 day, whereas the life span of tissue macrophages is several months or years.
Smoker's macrophages are alveolar macrophages whose characteristics, including appearance, cellularity, phenotypes, immune response, and other functions, have been affected upon the exposure to cigarettes. [1] These altered immune cells are derived from several signaling pathways and are able to induce numerous respiratory diseases.
Lipid-laden alveolar macrophages, also known as pulmonary foam cells, [2] are cells found in bronchoalveolar lavage (BAL) specimens that consist of macrophages containing deposits of lipids (fats). [3] The lipid content of the macrophages can be demonstrated using a lipid targeting stain like Oil Red O or Nile red.
Pathology: The lung vessels are congested with blood and this leads to pulmonary edema when plasma escapes in alveolar spaces. Rupture of congested capillaries leads to release of hemosiderin from damaged red blood cells. When alveolar macrophages engulf hemosiderin they are called heart failure cells.