Macrophages are formed from Macrophage-monocytic system Main stages of development, phenotypic characteristics, properties of apc. Modern detection methods. analysis for macrophages
Macrophages are immune systems that are vital for the development of non-specific defense mechanisms that provide the first line of defense against. These large immune cells are present in almost all tissues and actively remove dead and damaged cells, bacteria, and cellular debris from the body. The process by which macrophages engulf and digest cells and pathogens is called .
Macrophages also assist in cellular or adaptive immunity by capturing and presenting information about foreign antigens to immune cells called lymphocytes. This allows the immune system to better defend itself against future attacks by the same "invaders". In addition, macrophages are involved in other important functions in the body, including hormone production, immune regulation, and wound healing.
Macrophage phagocytosis
Phagocytosis allows macrophages to get rid of harmful or unwanted substances in the body. Phagocytosis is the form in which a substance is taken up and broken down by a cell. This process is initiated when a macrophage is approached by a foreign substance with the help of antibodies. Antibodies are proteins produced by lymphocytes that bind to a foreign substance (antigen), placing it in the cell for destruction. Once the antigen is detected, the macrophage sends out projections that surround and engulf the antigen (, dead cells, etc.), surrounding it in a vesicle.
An internalized vesicle containing an antigen is called a phagosome. in a macrophage, they fuse with a phagosome to form a phagolysosome. Lysosomes are membranous sacs of hydrolytic enzymes formed that are capable of digesting organic material. The content of enzymes in lysosomes is released into the phagolysosome, and the foreign matter is rapidly degraded. The degraded material is then expelled from the macrophage.
Development of macrophages
Macrophages develop from white blood cells called monocytes. Monocytes are the largest type of white blood cells. They have a large solitary, which often has a kidney shape. Monocytes are produced in the bone marrow and circulate in one to three days. These cells leave the blood vessels, passing through the endothelium of the blood vessels to enter the tissues. After reaching their destination, monocytes turn into macrophages or other immune cells called dendritic cells. Dendritic cells help in the development of antigenic immunity.
Macrophages, which are distinct from monocytes, are specific to the tissue or organ in which they reside. When there is a need for more macrophages in a particular tissue, living macrophages produce proteins called cytokines that cause monocyte responses to develop into the required type of macrophage. For example, infection-fighting macrophages produce cytokines that promote the development of macrophages that are specialized to fight pathogens. Macrophages, which are specialized in wound healing and tissue repair, develop from cytokines produced in response to tissue damage.
Function and location of macrophages
Macrophages are found in almost all tissues of the body and perform a number of functions outside the immune system. Macrophages help in the production of sex hormones in the male and female reproductive organs. They contribute to the development of networks of blood vessels in the ovary, which is vital for the production of the hormone progesterone. Progesterone plays an important role in the implantation of the embryo into the uterus. In addition, the macrophages present in the eye help develop the networks of blood vessels necessary for proper vision. Examples of macrophages that are found elsewhere in the body include:
- Central nervous system: microglia are glial cells found in nervous tissue. These extremely small cells patrol the brain and spinal cord, removing cellular waste and protecting against microorganisms.
- Adipose tissue: macrophages in adipose tissue protect against germs and also help fat cells maintain insulin sensitivity.
- Integumentary system: Langerhans cells are macrophages in the skin that serve immune function and help in the development of skin cells.
- Kidneys: macrophages in the kidneys help filter microbes from the blood and promote duct formation.
- Spleen: macrophages in the red pulp of the spleen help filter damaged red blood cells and microbes from the blood.
- Lymphatic system: macrophages stored in the central region of the lymph nodes filter the lymph with microbes.
- Reproductive system: macrophages help in the development of germ cells, the embryo and the production of steroid hormones.
- Digestive system: macrophages in the gut control the microbial-protective environment.
- Lungs: alveolar macrophages, remove germs, dust and other particles from respiratory surfaces.
- Bone: macrophages in bone can develop into bone cells called osteoclasts. Osteoclasts help reabsorb and assimilate bone components. The immature cells from which macrophages are formed are located in the non-vascular regions of the bone marrow.
Macrophages and diseases
Although the main function of macrophages is to protect against, sometimes these pathogens can evade the immune system and infect immune cells. Adenoviruses, HIV, and the bacteria that cause tuberculosis are examples of pathogens that cause disease by infecting macrophages.
In addition to these types of diseases, macrophages have been linked to the development of diseases such as cardiovascular disease, diabetes, and cancer. Macrophages in the heart contribute to cardiovascular disease by helping in the development of atherosclerosis. In atherosclerosis, the walls of the artery become thick due to chronic inflammation caused by white blood cells.
Macrophages in adipose tissue can cause inflammation, which induces insulin resistance in fat cells. This can lead to the development of diabetes. Chronic inflammation caused by macrophages can also promote the development and growth of cancer cells.
Chapter 3 Monocytes and Macrophages
Monocytes and macrophages are the main cells of the phagocytic mononuclear system (WHO) or the macrophage system of II Mechnikov.
Monocytes originate from a granulocyte-monocytic progenitor cell, macrophages - from monocytes that pass from the bloodstream into tissues. Macrophages are present in various tissues of the human body: in the bone marrow, in connective tissue, in the lungs (alveolar macrophages), in the liver (Kupffer cells), in the spleen and lymph nodes, in serous cavities (abdominal cavity, pleural cavity, pericardial cavity), in bone tissue (osteoclasts), in nervous tissue (microglial cells), in skin (Langerhans cells). They can be either free or fixed. In addition, macrophage elements include dendritic cells (having a large number of short branching processes) present in all tissues. During numerous operations for bone marrow transplantation from a donor of the opposite sex, the hematopoietic origin of alveolar macrophages, Kupffer cells, Langerhans cells and osteoclasts has been proven.
Having formed in the bone marrow, the monocyte stays there for 30 to 60 hours. After that, it divides and enters the systemic circulation. The circulation period of a monocyte in the blood is approximately 72 hours, where it matures. The nucleus of the monocyte transforms from round, first to bean-shaped, and then to clawed. In addition, there is a change in the structure of the genetic material of the cell. The color of the cytoplasm of a monocyte can be completely different - from basophilic to gray-blue or even pinkish. After leaving the bloodstream, the monocyte can no longer return to the systemic circulation.
Macrophages located in various tissues of the human body have a number of common features. In the study of alveolar macrophages, it was found that tissue macrophages maintain their population not only due to their formation in the bone marrow, but also due to their ability to divide and self-maintain. This distinctive feature of macrophages becomes apparent in the case of suppression of the formation of these blood cells in the bone marrow under the influence of radiation or drugs with a cytostatic effect.
The macrophage nucleus has an oval shape. The cytoplasm of the cell is quite large, has no clear boundaries. The diameter of a macrophage normally varies widely: from 15 to 80 microns.
The specific functional features of macrophages are the ability to adhere to glass, the absorption of liquid and more solid particles.
Phagocytosis is the “devouring” of foreign particles by macrophages and neutrophils. This property of body cells was discovered by I. I. Mechnikov in 1883; he also proposed the said term. Phagocytosis consists of capturing a foreign particle by a cell and enclosing it in a vesicle - a phagosome. The resulting structure moves deep into the cell, where it is digested with the help of enzymes released from special organelles - lysosomes. Phagocytosis is the most ancient and important function of macrophages, thanks to which they rid the body of foreign inorganic elements, destroyed old cells, bacteria, and immune complexes. Phagocytosis is one of the main defense systems of the body, one of the links of immunity. In macrophages, its enzymes, like many other structures, are subordinate to the role of these blood cells in immunity and, first of all, to the phagocytic function.
Currently, more than 40 substances produced by microphages are known. The enzymes of monocytes and macrophages that digest the resulting phagosomes are peroxidase and acid phosphatase. Peroxidase is found only in cells such as monoblasts, promonocytes, and immature monocytes. In the cells of the last two stages of differentiation, peroxidase is present in a very small amount. Mature cells and macrophages usually do not contain this enzyme. The content of acid phosphatase increases during the maturation of monocytes. Its greatest amount is in mature macrophages.
Of the surface markers of monocytes and macrophages, receptors for the Fc fragment of immunoglobulin G and for the complement component C 3 contribute to immune phagocytosis. With the help of these markers, immune complexes, antibodies, various blood cells coated with antibodies or complexes consisting of antibodies and complement are fixed on the surface of monocyte-macrophage cells, which are then drawn into the cell that performs phagocytosis and are digested by it or stored in phagosomes.
In addition to phagocytosis, monocytes and macrophages have the ability to chemotaxis, that is, they are able to move in the direction of the difference in the content of certain substances in cells and outside cells. Also, these blood cells can digest microbes and produce several complement components that play a leading role in the formation of immune complexes and in the activation of antigen lysis, produce interferon, which inhibits the reproduction of viruses, and secrete a special protein, lysozyme, which has a bactericidal effect. Monocytes and macrophages produce and secrete fibronectin. This substance is a glycoprotein in its chemical structure that binds cellular decay products in the blood, plays an important role in the interaction of a macrophage with other cells, in the attachment (adhesion) on the surface of a macrophage of elements subject to phagocytosis, which is associated with the presence of fibronectin receptors on the macrophage membrane.
The protective function of a macrophage is also associated with its ability to produce endogenous pyrogen, which is a specific protein that is synthesized by macrophages and neutrophils in response to phagocytosis. Being released from the cell, this protein affects the thermoregulatory center located in the brain. As a result, the body temperature set by the indicated center rises. An increase in body temperature due to the action of endogenous pyrogen contributes to the body's fight against an infectious agent. The ability to produce endogenous pyrogen increases as macrophages mature.
A macrophage not only organizes a system of nonspecific immunity, which consists in protecting the body from any foreign substance or cell that is foreign to a given organism or tissue, but also takes a direct part in a specific immune response, in the “presentation” of foreign antigens. This function of macrophages is associated with the existence of a special antigen on their surface. The HLA-DR protein plays a predetermining role in the development of a specific immune response. In humans, there are 6 variants of the HLA-DR-like protein molecule. This protein is present in almost all hematopoietic cells, starting from the level of pluripotent progenitor cells, but is absent on mature elements that have a hematopoietic nature. HLA-DR-like protein is also found in endothelial cells, and in spermatozoa, and in many other cells of the human body. On the surface of immature macrophages, present mainly in the thymus and spleen, an HLA-DR-like protein is also present. The highest content of this protein was found on dendritic cells and Langerhans cells. Such macrophage cells are active participants in the immune response.
A foreign antigen that enters the human body is adsorbed by the surface of the macrophage, absorbed by it, ending up on the inner surface of the membrane. The antigen is then cleaved in lysosomes. Fragments of the cleaved antigen are released from the cell. Some of these antigen fragments interact with the HLA-DR-like protein molecule, resulting in the formation of a complex on the macrophage surface. Such a complex releases interleukin I, which is supplied to lymphocytes. This signal is perceived by T-lymphocytes. A T-lymphocyte-amplifier develops a receptor for an HLA-DR-like protein associated with a fragment of a foreign antigen. An activated T-lymphocyte secretes a second signal substance - interleukin II and a growth factor for lymphocytes of all types. Interleukin II activates T-lymphocytes-helpers. Two clones of this type of lymphocytes respond to the action of a foreign antigen by producing B-lymphocyte growth factor and B-lymphocyte differentiation factor. The result of the activation of B-lymphocytes is the production of immunoglobulins-antibodies specific to this antigen.
Thus, despite the fact that the recognition of a foreign antigen is a function of lymphocytes without the participation of a macrophage that digests the antigen and connects part of it to the HLA-DR-like surface protein, antigen presentation to lymphocytes and an immune response to it are impossible.
Macrophages have the ability to digest not only bacterial cells, erythrocytes and platelets, on which some complement components are fixed, including aging or pathologically altered ones, but also tumor cells. This type of macrophage activity is called tumoricidal. From this it is impossible to draw a conclusion about the actual fight of macrophages with a tumor, namely, their “recognition” of this type of cells as a foreign tissue, due to the fact that in any tumor there are a lot of aging cells that are subject to phagocytosis, similarly to all non-tumor senescent cells.
Certain factors produced by cells of a monocyte-macrophage nature (for example, prostaglandins E, lysozyme, interferon) are involved in both immune function and hematopoiesis. In addition, macrophages help develop the eosinophilic response.
The macrophage nature of osteoclasts has been proven. Macrophages are able, firstly, to directly dissolve bone tissue, and secondly, to stimulate the production of the osteoclast-stimulating factor of T-lymphocytes.
This function of macrophages may be leading in the pathology caused by tumor and reactive proliferation of macrophages.
A very significant role is played by macrophages in the constancy of the internal environment. First of all, they are the only cells that produce tissue thromboplastin and trigger a complex cascade of reactions that ensure blood coagulation. However, apparently, an increase in thrombogenic activity in connection with the vital activity of macrophages can also be due to the abundance of both secreted by them and intracellular, secreted during cell decay, proteolytic enzymes, and the production of prostaglandins. At the same time, macrophages produce plasminogen activator, an anticoagulant factor.
This text is an introductory piece.4. B-lymphocytes. T-lymphocytes and macrophages In order for the functioning of the immune system to be normal, a certain ratio between all types of cells must be observed. Any violation of this ratio leads to pathology. This is the most general information about the organs of the immune
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12. Macrophages. microphages. Phagocytes Macrophages contain enzymes for the digestion of phagocytosed substances. These enzymes are contained in vacuoles (vesicles) called lysosomes and are able to break down proteins, fats, carbohydrates and nucleic acids. Macrophages cleanse
Chapter 4 Golden Rules for Prescribing Drugs for Acute Diseases Prescribe the minimum. Because every acute illness triggers a response in the body called an immune response, most infections or acute illnesses are self-limiting. Intervention
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Our body is surrounded by a huge number of negative and damaging environmental factors: ionizing and magnetic radiation, sharp temperature fluctuations, various pathogenic bacteria and viruses. To resist their negative influence and maintain homeostasis at a constant level, a powerful protective complex is built into the biocomputer of the human body. It unites organs such as the thymus, spleen, liver and lymph nodes. In this article, we will study the functions of macrophages that are part of the mononuclear phagocytic system, and also find out their role in the formation of the immune status of the human body.
general characteristics
Macrophages are "big eaters", this is the translation of the name of these protective cells, proposed by I.I. Mechnikov. They are capable of amoeboid movement, rapid capture and splitting of pathogenic bacteria and their metabolic products. These properties are explained by the presence in the cytoplasm of a powerful lysosomal apparatus, the enzymes of which easily destroy the complex membranes of bacteria. Histiocytes quickly recognize antigens and transmit information about them to lymphocytes.
The characteristic of macrophages as cells produced by the organs of the immune system indicates that they can be found in all vital structures of the body: in the kidneys, in the heart and lungs, in the blood and lymphatic channels. They have oncoprotective and signaling properties. The membrane contains receptors that recognize antigens, the signal of which is transmitted to active lymphocytes that produce interleukins.
Currently, histologists and immunologists believe that macrophages are cells formed from multipotent stem structures of the red bone marrow. They are heterogeneous in structure and function, differ in location in the body, degree of maturation and activity in relation to antigens. Let's consider them further.
Types of protective cells
The largest group is represented by phagocytes circulating in connective tissues: lymph, blood, osteoclasts and membranes of internal organs. In the serous cavities of the stomach and intestines, in the pleura and pulmonary vesicles, there are both free and fixed macrophages. This provides protection and detoxification of both the cells themselves and their blood supply elements - the capillaries of the pulmonary alveoli, the small and large intestines, as well as the digestive glands. The liver, as one of the most important organs, has an additional protective system of mononuclear phagocytic structures - Kupffer cells. Let us dwell on their structure and mechanism of action in more detail.
How the main biochemical laboratory of the body is protected
In the systemic circulation, there is an autonomous system of blood supply to the liver, called the portal vein circuit. Due to its functioning, from all organs of the abdominal cavity, blood immediately enters not into the inferior vena cava, but into a separate blood vessel - the portal vein. Further, it sends venous blood saturated with carbon dioxide and decay products to the liver, where hepatocytes and protective cells formed by the peripheral organs of the immune system break down, digest and neutralize toxic substances and pathogens that have entered the venous blood from the gastrointestinal tract. Protective cells have chemotaxis, therefore they accumulate in the foci of inflammation and phagocytize pathogenic compounds that have entered the liver. Now consider Kupffer cells, which play a special role in protecting the digestive gland.
Phagocytic properties of the reticuloendothelial system
The functions of liver macrophages - Kupffer cells - are to capture and process hepatocytes that have lost their functions. At the same time, both the protein part of the blood pigment and the heme itself are cleaved. This is accompanied by the release of iron ions and bilirubin. At the same time, bacteria are lysed, primarily E. coli, that have entered the bloodstream from the large intestine. Protective cells come into contact with microbes in the sinusoidal capillaries of the liver, then capture pathogenic particles and digest them using their own lysosomal apparatus.
Signaling function of phagocytes
Macrophages are not only protective structures that provide cellular immunity. They can identify foreign particles that have entered the cells of the body, since there are receptors on the phagocyte membrane that recognize molecules of antigens or biologically active substances. Most of these compounds cannot directly contact lymphocytes and trigger a defensive response. It is phagocytes that deliver antigenic groups to the membrane, which serve as beacons for B-lymphocytes and T-lymphocytes. Macrophage cells obviously perform the most important function of transmitting a signal about the presence of a damaging agent to the most active and rapidly acting immune complexes. Those, in turn, are able to react with lightning speed to pathogenic particles in the human body and destroy them.
Specific properties
The functions of the elements of the immune system are not limited to protecting the body from foreign environmental components. For example, phagocytes are capable of exchanging iron ions in the red bone marrow and spleen. Participating in erythrophagocytosis, protective cells digest and break down old red blood cells. Alveolar macrophages accumulate iron ions in the form of ferritin and hemosiderin molecules. They can be found in the sputum of patients suffering from heart failure with stagnation of blood in the pulmonary circulation and various forms of heart disease, as well as in patients who have had a heart attack aggravated by pulmonary embolism. The presence of a large number of immune cells in various types of clinical studies, for example, in vaginal swabs, in urine or semen, may indicate inflammatory processes, infectious or oncological diseases occurring in a person.
Peripheral organs of the immune system
Given the critical role of phagocytes, leukocytes and lymphocytes in maintaining the health and genetic uniqueness of the body, as a result of evolution, two lines of defense were created and improved: the central and peripheral organs of the immune system. They produce various types of cells involved in the fight against foreign and pathogenic agents.
These are primarily T-lymphocytes, B-lymphocytes and phagocytes. The spleen, lymph nodes, and follicles of the digestive tract are also capable of producing macrophages. This enables the tissues and organs of the human body to quickly recognize antigens and mobilize humoral and cellular immunity factors to effectively fight infection.
Macrophages(from other Greek μακρός - large, and φάγος - devourer (synonyms: histiocyte-macrophage, histophagocyte, macrophagocyte, megalophage-devourer)), polyblasts, cells of mesenchymal nature in the animal body, capable of actively capturing and digesting bacteria, residues dead cells and other foreign or toxic particles for the body. The term "macrophages" was introduced by Mechnikov.
The macrophages are blood monocytes, connective tissue histiocytes, endothelial cells of capillaries of hematopoietic organs, Kupffer cells of the liver, lung alveolar wall cells (pulmonary macrophages) and peritoneal walls (peritoneal macrophages).
It has been established that in mammals the precursors of macrophages are formed in the bone marrow. Active phagocytic properties are also possessed by cells of the reticular tissue of hematopoietic organs, combined with macrophages into the reticuloendothelial (macrophage) system, which performs a protective function in the body.
Morphology
The main cell type of the mononuclear phagocyte system. These are large (10 - 24 microns) long-lived cells with a well-developed lysosomal and membrane apparatus. On their surface there are receptors for the Fc-fragment of IgGl and IgG3, C3b-fragment C, B- and T-lymphocyte receptors, complement, other interleukins and histamine.
tissue macrophages
In fact, a monocyte becomes a macrophage when it leaves the vascular bed and enters the tissues.
Depending on the type of tissue, the following types of macrophages are distinguished.
Histiocytes - macrophages of the connective tissue; component of the reticuloendothelial system.
Kupffer cells - otherwise endothelial stellate cells of the liver.
Alveolar macrophages - otherwise, dust cells; located in the alveoli.
Epithelioid cells - components of the granuloma.
Osteoclasts are multinucleated cells involved in bone resorption.
· Microglia - cells of the central nervous system that destroy neurons and absorb infectious agents.
Macrophages of the spleen
Identification of macrophages
macrophages contain numerous cytoplasmic enzymes and can be identified in tissues by histochemical methods that detect these enzymes. Some enzymes, such as muramidase (lysozyme) and chymotrypsin, can be detected by labeled antibody testing (immunohistochemistry), which uses antibodies against enzyme proteins. Such monoclonal antibodies against various CD antigens are widely used to identify macrophages.
Functions of macrophages
Macrophage functions include phagocytosis, antigen processing, and interaction with cytokines.
Phagocytosis
· Non-immune phagocytosis: macrophages are able to phagocytize foreign particles, microorganisms and remnants of damaged cells directly, without triggering an immune response. However, phagocytosis of microorganisms and their destruction are greatly facilitated in the presence of specific immunoglobulins, complement and lymphokines, which are produced by immunologically activated T-lymphocytes.
· Immune phagocytosis: macrophages have surface receptors for C3b and Fc fragment of immunoglobulins. Any particles that are coated with immunoglobulin or complement (opsonized) are phagocytosed much more easily than "naked" particles.
• “Processing” of antigens: macrophages “process” antigens and present them to B- and T-lymphocytes in the required form; This cellular interaction involves the simultaneous recognition by MHC lymphocytes of molecules and "processed antigens" found on the surface of macrophages.
· Interaction with cytokines: Macrophages interact with cytokines produced by T-lymphocytes to protect the body against certain damaging agents. A typical result of this interaction is the formation of granulomas. Macrophages also produce cytokines, including interleukin-l, interferon-beta, and T- and B-cell growth factors. Various interactions of lymphocytes and macrophages in tissues are manifested morphologically in chronic inflammation.
The role of macrophages is not limited to the secretion of IL-1. In these cells, a number of biologically active substances are synthesized, each of which makes its contribution to inflammation. These include: esterases, proteases and antiproteases; lysosomal hydrolases - collagenase, alastase, lysozyme, α-macroglobulin; monokines - IL-1, colony-stimulating factor, a factor that stimulates the growth of fibroblasts; anti-infective agents - interferon, transferrin, transcobalamin; complement components: C1, C2, C3, C4, C5, C6; derivatives of arachidonic acid: prostaglandin E2, thromboxane A2, leukotrienes.
Good afternoon, dear readers!
Last time I told you about a very important group of blood cells - which are the real front line fighters of the immune defense. But they are not the only participants in operations to capture and destroy "enemy agents" in our body. They have helpers. And today I want to continue my story and explore functions
leukocytes - agranulocytes.
This group also includes lymphocytes, in the cytoplasm of which there is no granularity.
Monocyte is the largest representative of leukocytes. Its cell diameter is 10-15 microns, the cytoplasm is filled with a large bean-shaped nucleus. There are few of them in the blood, only 2 - 6%. But in the bone marrow, they are formed in large quantities and mature in the same microcolonies as neutrophils. But when they enter the bloodstream, their paths diverge. Neutrophils travel through the vessels and are always ready #1. And monocytes quickly settle in the organs and there they turn into macrophages. Half of them go to the liver, and the rest are settled in the spleen, intestines, lungs, etc.
Macrophages- these are sedentary, finally ripened. Like neutrophils, they are capable of phagocytosis, but, in addition, they have their own sphere of influence and other specific tasks. Under a microscope, a macrophage is a very prominent cell with impressive dimensions up to 40-50 microns in diameter. This is a real mobile factory for the synthesis of special proteins for its own needs and for neighboring cells. It turns out that a macrophage can synthesize and secrete up to 80 per day! various chemical compounds. You ask: what active substances are secreted by macrophages? It depends on where macrophages live and what functions they perform.
Functions of leukocytes:
Let's start with the bone marrow. There are two types of macrophages involved in the process of bone renewal - osteoclasts and osteoblasts. Osteoclasts constantly circulate through the bone tissue, look for old cells and destroy them, leaving behind free space for the future bone marrow, and osteoblasts form new tissue. Macrophages perform this work by synthesizing and secreting special stimulating proteins, enzymes and hormones. For example, they synthesize collagenase and phosphatase to destroy bone, and erythropoietin to grow red blood cells.
There are also cells - "nurses" and cells - "orderlies", which ensure the rapid reproduction and normal maturation of blood cells in the bone marrow. Hematopoiesis in the bones goes in islands - in the middle of such a colony there is a macrophage, and red cells of different ages crowd around. Performing the function of a nursing mother, a macrophage supplies growing cells with nutrition - amino acids, carbohydrates, fatty acids.
They play a special role in the liver. There they are called Kupffer cells. Actively working in the liver, macrophages absorb various harmful substances and particles coming from the intestines. Together with liver cells, they are involved in the processing of fatty acids, cholesterol and lipids. Thus, they unexpectedly turn out to be involved in the formation of cholesterol plaques on the walls of blood vessels and the occurrence of atherosclerosis.
It is not yet entirely clear where the atherosclerotic process begins. Perhaps, an erroneous reaction to “their” lipoproteins in the blood is triggered here, and macrophages, like vigilant immune cells, begin to capture them. It turns out that the voracity of macrophages has both positive and negative sides. Capturing and destroying microbes is, of course, a good thing. But excessive absorption of fatty substances by macrophages is bad and probably leads to a pathology that is dangerous for human health and life.
But it’s hard for macrophages to separate what’s good and bad, so our task is to alleviate the fate of macrophages and take care of our own health and the health of the liver ourselves: monitor nutrition, reduce the consumption of foods containing a large amount of fats and cholesterol, and twice a year remove toxins and toxins.
Now let's talk about macrophages, working in the lungs.
Inhaled air and blood in the pulmonary vessels are separated by the thinnest border. You understand how important it is in these conditions to ensure the sterility of the airways! That's right, here this function is also performed by macrophages wandering through the connective tissue of the lungs.
They are always filled with the remnants of dead lung cells and microbes inhaled from the surrounding air. Lung macrophages multiply right there in the zone of their activity, and their number increases sharply in chronic respiratory diseases.
To the attention of smokers! Dust particles and tar in tobacco smoke are highly irritating to the upper respiratory
The saddest thing is that, working for wear and tear, macrophages cease to perform very important functions - this is the ability to fight malignant cells. Therefore, chronic hepatitis is fraught with the development of liver tumors, and chronic pneumonia - with lung cancer.
Macrophages spleen.
In the spleen, macrophages act as "killers" by destroying aging red blood cells. On the shells of red blood cells, treacherous proteins are exposed, which are a signal for elimination. By the way, the destruction of old erythrocytes takes place both in the liver and in the bone marrow itself - wherever there are macrophages. In the spleen, this process is most evident.
Thus, macrophages are great workers and the most important orderlies of our body, while performing several key roles at once:
- involved in phagocytosis
- preservation and processing of important nutrients for the needs of the body,
- the release of several dozen proteins and other biologically active substances, which regulates the growth of blood cells and other tissues.
Well, we know functions of leukocytes - monocytes and macrophages.
And again, there was no time left for lymphocytes. About them, the smallest defenders of our body, we will talk next time.
In the meantime, let's get healthier and strengthen the immune system by listening to the healing music of Mozart - Symphony of the Heart:
I wish you good health and prosperity!
