Structure of the venous and lymphatic beds of the heart and their alteration in experimental pathology

The investigation performed has demonstrated that under a great deal of coronary, pulmonary and other organs' disorders, in the venous and lymphatic beds of the heart compensatory-adaptive and pathological changes occur. The earliest and deepest changes are noted in the microcirculatory bed. Most of morphological signs on vascular reconstruction are not specific and are observed at different kinds of clinical and experimental pathology. Changes in venous and lymphatic vessels of pathological conditions& do not only result from damage in the organ's wall or hemodynamical changes in the cavities of the cardiac vessels but they themselves can cause some disturbances in the miocardial microcirculation intensifying its hypoxia, congestive symptoms and enhancing the development of decompensation in the organ.     

Effect of alcoholic intoxication on the lymphatic bed of the heart]

Cardiac lymphatic bed was studied in 120 male corpses at the age of 17--55 years, normal and of those died from alcohol intoxication and from cardiac ischemia. The methods of intratissue injection of coloured masses, impregnation after V. V. Kuprianov, histological and histochemical investigations were applied. Data in figures were obtained by means of a grid for cyto-, histo- and stereometric investigations and by a scanning integrant microspectrophotometer sim-2. Statistical data were obtained by a computer "Mir". It was demonstrated that the cardiac lymphatic system responds in a definite way to alcohol intoxication. Four forms of structural state in the lymphatic bed elements were revealed, specific density of its different components was calculated. A certain connection was noted to occur between morphological changes under the effect of toxic doses of alcohol; there was also a reaction of compensatory-adaptive elements of lymphodynamics. A number of pathological changes in cardiac tissues resulting in heart insufficiency were presented. Peculiarities in poisoning phases were demonstrated morphologically.     

Structure of lymphatic vessels in the rat thyroid gland

The lymphatic bed of the thyroid gland has been studied in 24 intact rats. Three techniques facilitating to reveal lymphatic vessels in the organ have been used: preparation of semithin sections, injection of the blood bed with methyl methacrylate with a successive chemical extraction of the preparations, injection of the blood bed with liquid solution of methyl methacrylate with a consecutive study of the preparations in the scanning electron microscope. Methods of electron histochemistry (revealing horseradish peroxidase) and kryofractography have been applied. Construction of the thyroid lymphatic bed, structure of the wall are described, fibroblastic membrane (F-membrane) is revealed and the signs are presented, that allow to differentiate F-membrane from endothelium of the lymphatic capillaries. The pathways of lymph outflow in the rat thyroid gland consist of the following links: interstitial space in the interlobular spaces of the gland, into them the tissue liquor (lymph) is filtered ; plates of the F-membrane regulating direction of excessive albumin-containing liquor in the lymphatic capillaries, surrounding groups of 5-11 follicles, embracing the microlobule of the gland and situating in the interlobular spaces, deferent lymphatic vessels.     

Hematolymphatic transport in skin, subcutaneous tissue and superficial lamina of the fascia of the lower leg in varicose veins]

The lymphatic bed of the skin and subcutaneous tissues of the lower leg from 20 operated patients was studied by light and electron microscopy and by phlebographic methods. Three stages of development of the disease were examined: without complicated form of varicose veins, complicated form, and postthrombophlebitic syndrome. Morphological features of the state of the lymphatic bed of the skin, subcutaneous connective tissue and fascia of the lower leg in the initial stage of disease show the fine structure changes of lymphatic vessels and capillary walls interpreted as a compensation phenomenon. It seems that the structure alterations of endotheliocytes of lymphatic capillaries and the connective tissue surrounding them found in this study in the complicated form of the disease and the postthrombophlebitic syndrome are the basis of the mechanism of transport-resorption insufficiency of the lymph vessels' terminal flow paths.     

Structure of the excretory ducts, intraorganic lymphatic vessels, tissue canals and intercellular space of various organs (data of scanning electron microscopy injection replicas)

Architectonics of the biliary canaliculi and intrahepatic ducts systems, as well as intraorganic urinary pathways in white rats have been investigated by means of scanning electron microscopy of injection replica. Acinar structure of the intralobular part of the biliary bed has been proved. Anastomoses between the biliary canaliculi of the neighbouring lobules have been demonstrated. A useful method for obtaining injection replica of the intraorganic lymphatic vessels is filling of the ductal system of the parenchymatous organs with solid resins (methylmethacrylate+) under a high (nonphysiological) pressure. Casts of periportal and paravenous hepatic lymphatic vessels have been obtained. An ability of methylmethacrylate to replicate intercellular and connective tissue spaces is verified. Casts of the perisinusoid spaces (Disse) are obtained for the first time.     

Development of the paravascular bed of the vessels of the human heart during the prenatal period of ontogenesis

The paravascular bed of the cardiac vessels has been studied in 128 human fetuses at the age of 3-9 lunar months. Anatomical and histological techniques have been used, morphometrical analysis has been carried out. The paravascular bed of the cardiac wall vessels begins to form from the vascular epicardial network and from the paraneural vessels in 5-month-old fetuses. The paravasal longitudinal tracts are the first to form (the venous ones preceed the arterial). During the seventh month the nutritive vessels and the intramural networks of the main cardiac arteries and veins develop. The formation of the paraarterial bed is connected with the vascular diameter and with thickness of the arterial walls. Certain regularities in development of the venous paravascular bed are defined. By the beginning of the 8th month there are all main components of the paravascular bed of the cardiac vessels.     

The anlage of the duodenal lymphatic bed: morphogenetic prerequisites, structure and importance

The anlage of the duodenal lymphatic bed takes place on the 3d month of the human intrauterine life. In the intestinal villi there are chyle sinuses, that fuse into presumptive lymphatic vessels, having capillary structure, when they get out of the villi. Intraorganic vessels turn into extraorganic ones, they flow into the pancreatoduodenal lymphatic vessels. In their lumens stromal anlage of the lymphatic nodes are formed as a result of invagination of the blood vessels. Development of the lymphatic bed in the duodenum preceded with formation of intestinal villi (this contributes to absorption of the intestinal content) and deformity of the superior mesenteric vein (this probably makes difficult the organ's drainage). The situation is solved owing to the lymphatic bed anlage. It is, evidently, formed by means of switching off a part of embryonal veins from the blood stream.     

The conjunctival lymphatic bed of the rabbit in exposure to ultraviolet radiation]

Morphofunctional state of the lymphatic bed of the conjunctiva has been studied under effect of ultraviolet radiation. A comparative characteristics of development of the clinical picture and morphological criteria of the harmful effect of the ultraviolet radiation is presented. When all clinical symptoms disappear, there is no complete restoration of the capacitance function of the lymphatic vessels and intracellular regeneration of ultra-microscopical structures of endotheliocytes.     

Structural changes in the small intestine wall and its lymphatic bed after gastrectomy

Morphologically and histochemically structural changes of the small intestine wall and its lymphatic bed have been studied in 104 dogs after the stomach resection. After the operation an increase in the diameter of the lymphatic capillaries and vessels takes place. Lateral dilatations and protrusions in the capillary walls appear, new anastomoses in all the membranes are formed, they are mostly manifested in the mucous membrane. Histopathological rearrangement in the small intestine wall is demonstrated as edema of the mucous membrane, as plethora of the vessels, as lymphoid infiltration and as changes of the villi forms.     

Lymphatic vasculature: a molecular perspective

The lymphatic vasculature comprises an intricate network of vessels critical for fluid homeostasis, immune surveillance and fat absorption. Recent studies have provided insights into the developmental processes and molecular mechanisms controlling the formation and remodelling of the lymphatic vessels. These studies have further demonstrated the essential and active role of the lymphatic vessels in various pathological conditions and advanced our understanding of the progression of human diseases, such as inflammation and tumorigenesis. In the context of the latest exciting findings, we review here the current understanding of the mechanisms of lymphatic development and contribution of lymphatic vessels to pathological conditions.     

Scanning electron microscope study of the liver microcirculation

During the experimental investigation performed in dogs and rats, by means of scanning electron microscopy of corrosive anatomical preparations, the spatial organization of all parts of the hepatic vascular bed (arterial, venous and lymphatic) has been studied, specific features of their components construction have been described. Within the limits of one hepatic lobule the number of vessels included in the portal vein system exceeds that of the arterial ones, originating from the proper hepatic artery system. In every part of the vascular bed the gradient of the form, orientation and pronouncement of the nuclei-containing zones in endotheliocytes and myocytes has been established. Various appliances participating in the blood and lymph stream regulation in different parts of the vascular bed have been revealed. As initial elements of the lymph bed, closed digital or loop-like capillaries should be regarded, they localize in the organ's connective tissue framework. Around the portal and hepatic veins and their branches, as well as around the biliary ducts, well developed plexuses of the lymphatic and blood capillaries and vessels localize, they are the main draining pathways of the organ. The degree of development and pronouncement of these plexuses depends on the lumen size in the formation they accompany.     

Morphofunctional changes in the hemo- and lymphomicrocirculatory bed of the uterus and its regional lymph nodes in venous congestion during pregnancy

Interrelations of the blood and lymphatic systems of the uterus have been examined in rats at pregnancy complicated with the ++phlebo-occlusive syndrome. Blood stream impediment in the caudal vena cava results in increasing diameter of the arterioles, capillaries and venules of the endo- and myometrium. Certain disturbances of blood circulation in the uterus at the ++phlebo-cclusive syndrome in the pregnancy animals, as a rule, reflect in the uterine lymph outflow; this is demonstrated as dilatation and deformity of the lymphatic vessels and capillaries, appearance of protrusions of the lymphatic vessels wall. There is a definite co-ordination in the reaction to the caudal vena cava occlusion in the intra-, ++extra-organic uterine lymphatic bed and in its regional lymph nodes, manifested as the following morphological signs: decreasing relative volume, that the lymphoid tissue occupies and increasing relative volume of the cortical and medullary intermediate sinuses.     

Intraorganic lymphatic bed of the cattle heart

Lymphomicrocirculatory networks of endocardium, myocardium and epicardium, as well as lymphatic vessels of four orders represent the intraorganic lymphatic bed of the cattle heart. In the endocardium there is a lymphatic network with close loops and a small amount of blindly beginning capillaries. The capillary lymphatic bed of the endocardial trabeculae carneae is much more dense than that in the other part of the endocardial surface. The spatial lymphatic network of the myocardium is joined with the lymphomicrocirculatory networks of the endocardium and epicardium by means of a large amount of connections. The epicardial lymphatic bed is formed by blindly beginning lymphatic capillaries, which situate in close and nonclose loops of the lymphatic network. In the epicardium there is only one lymphatic network. The size of the loops and the diameter of the lymphatic capillaries is directly proportional to the age of the animals.     

Animal models for the study of lymphatic insufficiency

Lymphedema is the term commonly employed to describe the spectrum of pathological states that arise as a consequence of functional lymphatic insufficiency. These human disease entities currently lack an effective cure. Satisfactory therapeutic strategies for both primary and secondary lymphedema will require additional insight into the complex cellular mechanisms and responses that comprise both normal lymphatic function and its regional derangement in states of pathologic dysfunction. Such insights must, initially, be derived from suitable animal models of the chronic human disease process. Historically, efforts to replicate the untreated disease of human lymphedema in animals, through surgery, irradiation, and toxicology, have been fraught with difficulty. The major impediments to the creation of satisfactory animal models have included an inability to reproduce the chronic disease in a stable, reproducible format. Recently, with the promise of potentially successful growth factor-mediated therapeutic lymphangiogenesis, and with the enhanced availability of investigative tools to assess therapeutic responses to molecular therapies, there has been a resurgence of interest in the development of viable animal models of lymphatic insufficiency. Current research has led to the development of genetic and postsurgical models of lymphedema that closely simulate the human conditions of primary and secondary lymphatic insufficiency, respectively. Such models will help to refine the assessment of various therapeutic approaches and their potential applicability to human disease interventions.     

The relationship between the lymphatic vessels of the nerves of the human lower extremity and the perineural spaces]

The lymphatic vessels and perineural spaces of superficial and profound nerves of the extremity were studied on the material of 50 lower extremities of corpses of humans by the method of intratissue and direct injection. Initial lymphatic capillaries and extraorganic lymphatic vessels and their paravasal plexuses were found. It is concluded that closed lymphatic capillaries having no immediate connection with the perineural space are the roots of the lymphatic bed in the nerve.     

Morphologic aspects of local blood flow regulation in the myocardium

In 67 preparations of the human hearts at the first and second periods of mature age, spatial interrelations between blood vessels and cardiac muscle fibers in the ventricle myocardium have been studied. All the elements of the myocardial blood bed are oriented under a certain angle in relation to the cardiac muscle fibers. Regular arrangement of the arteries and sinusoid dilated veins under endocardium on the top of the papillary muscles and in the muscular trabecules is demonstrated. As proves the mathematical model, the slope orientation of the blood bed elements towards the cardiac muscle fibers ensures and adequate realization of the external influence of the contractile cardiomyocytes to the successive movement of blood along the intramural myocardial vessels. From morphological positions, a conclusion on the mechanism of the intracavitary pressure effect on blood movement along the intramural veins of the ventricular myocardium is argued. A conclusion is made on the leading role of the extravascular factors (intramyocardial and intercavitary pressure) in the local regulation of the blood stream in the myocardium and in development of working cardiac hyperemia.     

Lymphatic vascular morphogenesis in development, physiology, and disease

The lymphatic vasculature constitutes a highly specialized part of the vascular system that is essential for the maintenance of interstitial fluid balance, uptake of dietary fat, and immune response. Recently, there has been an increased awareness of the importance of lymphatic vessels in many common pathological conditions, such as tumor cell dissemination and chronic inflammation. Studies of embryonic development and genetically engineered animal models coupled with the discovery of mutations underlying human lymphedema syndromes have contributed to our understanding of mechanisms regulating normal and pathological lymphatic morphogenesis. It is now crucial to use this knowledge for the development of novel therapies for human diseases.     

Ultrastructure of mesenteric lymphatic postcapillaries of the small intestine of the human fetus

Lymphatic vessels of the small intestine mesentery have been investigated in 36 human fetuses 3-6-month-old. Lymphatic postcapillaries are the predominant link in the lymphomicrocirculatory bed studied. They differ from the capillaries only by presence of valves. Intersegmentary valves and velves at the places where the lymphatic capillaries get into the postcapillaries are described; they are situated along the whole length of the postcapillary. Both types of the valves can be uni- and besinusoid, and according to the number of endotheliocytes, covering the sinuses, uni- and multicellular. Cells of fibroblastic line and developing collagenous fibers are inevitable structural components and situate in their base. Ultrastructural peculiarities of the lymphatic postcapillary wall are described. Structural mechanisms responsible for dilatation and narrowing of the vascular lumen (formation of the pulse wave) are discussed. The data obtained support the conception successively elaborated by V. V. Kuprianov on the lymphatic postcapillary as an inevitable link of the lymphomicrocirculatory bed.     

Development of the lymphatic bed of the human esophageal wall]

The lymphatic capillaries are firstly determined in fetuses at the age of 3-4 months in the oesophagus submucous lamina. In fetuses of 5-6 months of age transition of the lymphatic capillaries from the submucous lamina into the mucous membrane proper is noted. In fetuses of 6 months of age perivascular lymphatic capillaries and vessels appear. They form peculiar paths around arterioles, venules, arterial branches and venous tributaries. The lymphatic bed of the oesophageal wall is rather well developed in mature fetuses and newborns. In adult and old persons a partial reduction of the lymphatic bed in the oesophageal wall is observed.     

Organ and tissue-specific properties of the microcirculatory bed of the heart

The auricular and ventricular microcirculatory bed has been studied in persons of mature age, not suffering from any cardio-vascular diseases during their life. As a whole, 48 objects have been studied. The microcirculatory bed has been revealed in sections of the cardiac wall 70-100 mcm thick using silver nitrate impregnation after V. V. Kuprianov. Organ- and tissue-specific properties of the vascular microcirculatory bed are revealed in interrelations of the vessels and the structural elements of the cardiac wall (myocardium, and connective tissue structures), in position of nuclei of the endothelial cells of the capillary wall and in places of the capillary branchings. Principle differences in structure of the auricular and ventricular microcirculatory bed are demonstrated. The notion the organ- and tissue-specific properties of the microcirculatory bed vessels is discussed.