Coagulative necrosis
Encyclopedia
Coagulative necrosis is a type of accidental cell death
typically caused by ischemia
or infarction
.
It is characterised by the 'ghostly' appearance of cells under light microscopy in the affected area of tissue. In coagulative necrosis the architecture of dead tissue is preserved for at least a couple days. It is believed that the injury denatures structural proteins as well as lysosomal enzymes thus blocking the proteolysis of the damaged cells. The lack of lysosomal enzymes allows it to maintain a "coagulated" morphology for some time. Like most types of necrosis
if enough viable cells are present around the affected area regeneration
can occur.
conditions that do not involve severe trauma
, toxins or an acute or chronic
immune response. The lack of oxygen causes cell death in a localised area which is perfused by blood vessels failing to deliver primarily oxygen, but also other important nutrients. It is important to note that while ischemia in most tissues of the body will cause coagulative necrosis, in the central nervous system ischemia causes liquefactive necrosis
as there is very little structural framework in neural tissue.
.
s adjacent to the affected tissue will replicate and replace the cells which have been killed during the event. Labile cells are constantly undergoing mitosis
and can therefore help reform the tissue, whereas nearby stable and permanent cells (e.g. neurons and cardiomyocytes) do not undergo mitosis and will not replace the tissue affected. Fibroblasts will also migrate to the affected area depositing fibrous tissue producing fibrosis
or scarring in areas where viable cells do not replicate and replace tissue.
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
typically caused by ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
or infarction
Infarction
In medicine, infarction refers to tissue death that is caused by a local lack of oxygen due to obstruction of the tissue's blood supply. The resulting lesion is referred to as an infarct.-Causes:...
.
It is characterised by the 'ghostly' appearance of cells under light microscopy in the affected area of tissue. In coagulative necrosis the architecture of dead tissue is preserved for at least a couple days. It is believed that the injury denatures structural proteins as well as lysosomal enzymes thus blocking the proteolysis of the damaged cells. The lack of lysosomal enzymes allows it to maintain a "coagulated" morphology for some time. Like most types of necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
if enough viable cells are present around the affected area regeneration
Regeneration (biology)
In biology, regeneration is the process of renewal, restoration, and growth that makes genomes, cells, organs, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. At its most...
can occur.
Causes
Coagulative necrosis is most commonly caused by hypoxicHypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...
conditions that do not involve severe trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
, toxins or an acute or chronic
Chronic (medicine)
A chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
immune response. The lack of oxygen causes cell death in a localised area which is perfused by blood vessels failing to deliver primarily oxygen, but also other important nutrients. It is important to note that while ischemia in most tissues of the body will cause coagulative necrosis, in the central nervous system ischemia causes liquefactive necrosis
Liquefactive necrosis
Liquefactive necrosis is a type of necrosis which results in a transformation of the tissue into a liquid viscous mass. Often it is associated with focal bacterial or fungal infections...
as there is very little structural framework in neural tissue.
Macroscopic
The macroscopic appearance of an area of coagulative necrosis is a pale segment of tissue contrasting against surrounding well vascularised tissue and is dry on cut surface. The tissue may later turn red due to inflammatory response. The surrounding surviving cells can aid in regeneration of the affected tissue unless they are stable or permanent.Microscopic
The microscopic anatomy shows a lighter staining tissue (when stained with H&E) containing no nuclei with very little structural damage giving the appearance often quoted as 'ghost cells'. The decreased staining is due to digested nuclei which no longer show up as dark purple when stained with hematoxylin and removed cytoplasmic structures giving reduced amounts of intracellular protein reducing the usual dark pink staining cytoplasm with eosinEosin
Eosin is a fluorescent red dye resulting from the action of bromine on fluorescein. It can be used to stain cytoplasm, collagen and muscle fibers for examination under the microscope. Structures that stain readily with eosin are termed eosinophilic....
.
Regeneration
As the majority of the structural remnants of the necrotic tissue remains, labile cellLabile cell
In cellular biology, labile cells are cells that multiply constantly throughout life. They spend little or no time in the quiescent G0 phase of the cell cycle, but regularly perform cell division.This is the case for only a minority of cells in the body...
s adjacent to the affected tissue will replicate and replace the cells which have been killed during the event. Labile cells are constantly undergoing mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...
and can therefore help reform the tissue, whereas nearby stable and permanent cells (e.g. neurons and cardiomyocytes) do not undergo mitosis and will not replace the tissue affected. Fibroblasts will also migrate to the affected area depositing fibrous tissue producing fibrosis
Fibrosis
Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue in a reparative or reactive process. This is as opposed to formation of fibrous tissue as a normal constituent of an organ or tissue...
or scarring in areas where viable cells do not replicate and replace tissue.
External links
- http://library.med.utah.edu/WebPath/CINJHTML/CINJ016.html