17. Mixed dystrophies: definition, classification. Types of hemoglobinogenic pigments, their significance for the body.

They occur when the metabolism of complex proteins - chromoproteins, nucleoproteins and lipoproteins, as well as minerals - is disrupted. Classification. There are 3 groups:

1) hemoglobinogenic (various hemoglobin derivatives);

2) proteinogenic, or tyrosinogenic (related to tyrosine metabolism);

3) lipidogenic, or lipopigmented (formed during the metabolism of fats).

Hemoglobin (high molecular weight chromoprotein) is an iron–containing respiratory pigment that forms the basis of red blood cells and acts as an oxygen carrier. As a result of the physiological breakdown (hemolysis) of erythrocytes and hemoglobin, pigments are formed:

1. ferritin (- an ironoprotein containing up to 23% iron; depending on the origin, anabolic (formed from iron absorbed in the intestine) and catabolic (formed from iron of hemolysed erythrocytes) ferritin are distinguished; has antigenic properties; forms Prussian blue (iron-containing iron); contains a large amount of ferritin in the liver (ferritin depot), the spleen, bone marrow and lymph nodes, where its metabolism is associated with the synthesis of hemosiderin, hemoglobin and cytochromes;

2. hemosiderin (- is formed during the cleavage of heme and is a polymer of ferritin; the cells in which hemosiderin is formed are called sideroblasts; hemosiderin is contained in the reticular and endothelial cells of the spleen, liver, bone marrow, lymph nodes;

3. bilirubin is a bile pigment; it contains neither iron nor protein; it is formed in the histiocytes-macrophages system; it is transported by blood to the liver in an unbound form (indirect or unbound bilirubin, soluble in lipids) in combination with albumin (direct or bound bilirubin). In the liver, bilirubin enzymatically binds to glucuronic acid, forming a water-soluble direct (bound) bilirubin, which is excreted by liver cells with bile, and then enters the intestine (cholebilirubin). In the intestine, due to the activity of bacteria, it turns into urobilinogen; normally, bilirubin is found dissolved in bile and in small amounts in blood plasma;

Biological role. Endogenous pigments (chromoproteins) are colored proteins that are used to produce:

1. respiration (hemoglobin, cytochromes);

2. secretion (bile) and hormones (serotonin);

3. protection of the body from radiation energy (melanin);

4. replenishment of iron reserves (ferritin);

5. balance of vitamins (lipochromes), etc.

18. Pathology of hemoglobinogenic pigments: types, normal metabolism and pathology. General hemosiderosis: causes, mechanisms of development, macro- and microscopic changes in organs, methods of detection.

Hemoglobin (high molecular weight chromoprotein) is an iron–containing respiratory pigment that forms the basis of red blood cells and acts as an oxygen carrier. As a result of the physiological breakdown (hemolysis) of erythrocytes and hemoglobin, pigments are formed:

1. ferritin (- an ironoprotein containing up to 23% iron; depending on the origin, anabolic (formed from iron absorbed in the intestine) and catabolic (formed from iron of hemolysed erythrocytes) ferritin are distinguished; has antigenic properties; forms Prussian blue (ferricinaceous iron); a large amount of ferritin is contained in the liver (ferritin depot), the spleen, bone marrow and lymph nodes, where its metabolism is associated with the synthesis of hemosiderin, hemoglobin and cytochromes;

in pathological conditions, the amount of ferritin can increase both in the blood and in tissues; an increase in the content of ferritin in tissues is observed in hemosiderosis, since polymerization of ferritin leads to the formation of hemosiderin).

2. hemosiderin (- is formed during the cleavage of heme and is a polymer of ferritin; the cells in which hemosiderin is formed are called sideroblasts; hemosiderin is found in the reticular and endothelial cells of the spleen, liver, bone marrow, lymph nodes; in the intercellular substance it undergoes phagocytosis by siderophages;

in the conditions of pathology, excessive formation of hemosiderin – hemosiderosis – M.B. is both common (with intravascular destruction of erythrocytes - intravascular hemolysis) and local (develops with extravascular destruction of erythrocytes – extravascular hemolysis.

3. bilirubin is a bile pigment; it contains neither iron nor protein; it is formed in the histiocyte-macrophage system; it is transported by blood to the liver in an unbound form (indirect or unbound bilirubin – soluble in lipids) in combination with albumin (direct or bound bilirubin). In the liver, bilirubin enzymatically binds to glucuronic acid, forming a water-soluble direct (bound) bilirubin, which is excreted by liver cells into bile, and then enters the intestine (cholebilirubin). In the intestine, due to bacterial activity, it is converted into urobilinogen; normally, bilirubin is found dissolved in bile and in a small amount in blood plasma;

a violation of bilirubin metabolism is associated with a disorder of its formation and excretion - it leads to an increase in blood plasma content with its accumulation in tissues and jaundice staining of the skin, sclera, mucous membranes, serous membranes and internal organs - jaundice).

+In pathology, a number of new enzymes can be formed:

1. hematoidin - does not contain iron; occurs when erythrocytes and hemoglobin disintegrate intracellularly, 5-10 days after hemosiderin, but unlike hemosiderin does not remain in cells and, when they die, it turns out to lie freely among necrotic masses; accumulations of hematoidin are found in more or less old hematomas, scarring infarcts, and far from living tissues – in in the central areas of hemorrhages, and not along the periphery; its formation is associated with cell decay, i.e. with extinction and cessation of vital activity in the hemorrhage site with insufficient oxygen access.

2. hematins are an oxidized form of heme; they are formed during hydrolysis of oxyhemoglobin; they contain iron in a bound state; hematins include hemomelanin (malarial pigment); hydrochloric acid hematin (gemin); formalin pigment; histochemical properties of these pigments are identical.

3. porphyrin (-a fluorescent pigment similar in structure to bilirubin, contains iron; normally it is contained in small amounts in the blood and urine, plays the role of a melanin antagonist and increases skin sensitivity to light; if its metabolism is disrupted, the content of porphyrin in the blood (porphyrinemia) and in urine (porphyrinuria) increases; urine containing a large amount of porphyrin, it turns red; the pigment is also found in feces. This condition is called porphyria.

General hemosiderosis: causes, mechanisms of development, macro- and microscopic changes in organs, methods of detection.

General or generalized hemosiderosis is observed with intravascular destruction of erythrocytes (intravascular hemolysis). Causes of general hemosiderosis:

• diseases of the hematopoiesis system (anemia, hemoblastosis);

• intoxication caused by hemolytic poisons (saponin, snake venom, acetic acid) and salts of heavy metals (lead);

• some infectious diseases (sepsis, malaria, brucellosis, anaerobic infections, etc.);

• transfusions of non-group, Rhesus-incompatible and bacterially contaminated blood.

Micro-: Excess iron is deposited as hemosiderin in macrophages of all organs, especially bone marrow, liver and spleen. The role of sideroblasts is performed in these organs by reticular, endothelial and histiocytic elements. Hemosiderosis is an indicator of hemolysis and thus reflects the severity of anemia. A large number of siderophages appear that do not have time to absorb hemosiderin, which loads the intercellular substance. As soon as the intracellular mechanisms of iron deposition are depleted, free iron accumulates and is restored in tissues with the formation of toxic free radicals containing active oxygen.

Macro-: The spleen, lymph nodes, and bone marrow turn brown. At the same time, the most dramatic morphological changes are observed in parenchymal organs. Vivid forms of hemosiderosis, especially of the liver (“pigmented cirrhosis"), pancreas, salivary glands, are observed in hemochromatosis