Immune System and Regeneration

The review article is devoted to a role of pluripotent stem cells and immune system in renewal of tissues (regeneration). Cell-precursors (progenitor cells) and differentiated cells can be divided a limited number of times and aren't capable of ensuring regeneration of tissues during the whole process of ontogenesis. The renewal of tissues during the whole long period is impossible without the participation of a specialized system which is responsible for regeneration. The given system is made up of pluripotent stem cells which are capable of differentiating themselves into all types of somatic cells, and into a line of genital cells. These stem cells are also capable of reproducing themselves over the whole lifespan of the organism. The participation of pluripotent stem cells and the possible mediation of antigen-presenting cells and T-helpers/T-suppressors in the complex with molecules of the MHC I class/II class make it possible to consider that exactly this immune system is responsible for regeneration of tissues in the organism. The participation in the regeneration process is the most important (and perhaps the leading) function of the immune system. With age the quantity of pluripotent stem cells gradually decreases. It leads to violation of renewal of tissues at people over 35-40 years old. Transfusion of mononuclear fraction of peripheral blood procured from young donors 18-23 years old with the same blood groups and sex as the recipient (RF patent number 2350340), allows people over 40-50 years old to reestablish the pool of pluripotent stem cells and the process of tissue renewal.

[Early reactive changes of the astrocytes in the midbrain paranigral nucleus after forebrain ischemia and cerebroprotector Ropren administration in rats]

The aim of this study was to detect morphological equivalents of cerebroprotective effect of polyprenol drug Ropren on the astrocytes of the midbrain paranigral nucleus (PNN) which are located outside the focus of forebrain ischemia in rats. In mature rats (n = 8) the cerebral ischemia was reproduced under the narcosis by bilateral occlusion of both carotid arteries. Four rats received daily intraperitoneal injections of 11.6 mg/kg of cerebroprotector Ropren. Sham-operated animals served as a control. The animals were decapitated at experimental day 7. Astrocytes of anterior ventral portion of midbrain PNN were studied using an immunocytochemical method demonstrating glial fibrillary acidic protein. The number of astrocytes, their cell body profile area, the length of their major processes and the distance between their cell bodies and capillary wall were measured. It was found that Ropren suppressed astrocyte hypertrophic reaction, their migration towards the vascular wall and presumably stimulated the proliferation of these cells.

[On the method of forensic medical examination of the injuries inflicted and traces left by the objects having the rubber surface]

A method of forensic medical examination of the injuries inflicted and traces left by the objects having the rubber surface is proposed. The method permits to reveal the facts of contact of injurious rubber things with biological and non-biological objects. Its application extends the possibilities for determining the direction of movement and the weight of a vehicle running over the body of the victim.

[Structure of venular vessels and cellular composition of hepatic sinusoidal capillaries in newborn infants]

The objective of this study was to identify the structural peculiarities of terminal interlobular venules and to determine the number of endotheliocytes, hepatic fat-storing cells (FSC) and stellate macrophages (SM) in the liver of newborn infants. Liver fragments were obtained from 5 healthy newborn infants during medico-legal autopsies. In the sections stained using Mallory's method, the relation of the connective tissue of terminal portal tracts with the adventitia of interlobular veins was determined. The numbers of endotheliocytes, FSC and CD68+ SM were counted in different zones of the liver acini. It was found that the adventitia of the terminal interlobular venules was completely represented by the connective tissue of the terminal portal tracts. Anastomoses with the sinusoidal capillaries (SC) via the circumlobular venules form the preterminal veins. FSC were concentrated in the central and periportal zones of the liver acinus, endotheliocytes of SC - in the periportal and peripheral zones, while SM were evenly distributed in all parts of the liver acinus. Thus, in newborn infants, liver cells possessing fibrogenic potential were numerous and were accumulated mainly near terminal interlobular venules, their circumlobular branches and within their adventitia.

[Reactive changes of the rat brain cellular elements under different conditions of circulatory hypoxia]

The aim of this study was to detect structural, spatial and quantitative changes of cellular elements of midbrain paranigral nucleus (PNN) and telencephalic anterior cingulate area (ACA) under different conditions of circulatory hypoxia. PNN anteriormedial part and ACA layers V-VI were examined in adult rats 7 days (n=4) after an occlusion of both common carotid arteries as well as in intact (1st control, n=4) and sham-operated animals (2nd control, n=4). In histological the sections, stained with Nissl cresyl violet, and using the methods of glial fibrillary acidic protein and an Ibal-protein detection, the proportions of unmodified, hypochromic, pyknomorphic neurons and ghost cells were determined as well as the numbers of astrocytes, oligodendrocytes, microgliocytes and endotheliocytes. Cell body area of neurons and gliocytes, and the distance between cell bodies and capillaries were measured, a gliocyte-neuronal index was calculated. It was found that brain cellular elements that survive different conditions of a circulatory hypoxia underwent a range of pathological changes. Neurons were in process of nuclear pyknosis, lysis and transformation into the ghost cells. The cells within the hypoxia nuclear zone were prone to death or pyknosis. The neurons located outside the area of hypoxia which were affected only by a humoral impact of reactions of the glutamate-calcium cascade, frequently underwent acute swelling. Microgliocyte reaction in the form of poorly expressed increase in their number and structural signs of activation was an early diffuse manifestation of a prosencephalic focal hypoxia. Endotheliocyte proliferation 7 days after of ischemic challenge was not associated with a chain of cascade reactions and was observed only in the hypoxia focus. Concentration of viable neurons and astrocytes near blood capillaries, as well as an increase in the number of satellite form gliocytes is an adaptation mechanism and a condition for the survival of cells during various types of brain exposure to ischemia.

[Activation of programmed cell death and degenerative changes of neurons of mesocorticolimbic dopaminergic system as a possible cause of inherited alcohol addiction]

It is known that the insufficiency of mesocorticolimbic dopaminergic system (MDS) lies in the basis of inherited alcohol addiction (IAA). The understanding of the pathogenesis of IAA is hampered by the absence of data on the number and volume of neuronal cell bodies in MDS and on the rate of their programmed cell death in the offspring of alcohol-dependent humans and animals. Morphological changes of neurons and macroglial cells of major MDS parts were studied in the offspring of intact Wistar rats (n = 20) and in the offspring of female rats that consumed 15% alcohol during five months, including the periods of pairing and pregnancy (n = 20). The material was obtained at 0, 5, 10, and 61 days. In brain histological sections stained with Nissl stain and using glial fibrillar acidic protein immunohistochemistry, the proportions of unaffected, hypochromic, pyknomorphic, and shadow-like neurons were determined together with the volume of unaffected neurons, oligodendrocyte, astrocyte numbers and neurono-glial index. At day 61 significant reduction in the number of unaffected and slightly changed MDS neurons was found that resulted from increased programmed cell death of neurons and their shrinkage accompanied by a partial compensatory increase in the intensity of neuron-glial interactions due to the increased number of oligodendrocytes. The alcohol addiction behavior of experimental animals was also demonstrated.

[Morphological signs of ethanol poisoning, alcohol abstinence and chronic alcoholic intoxication in the mesocorticolimbic dopaminergic system]

Forensic medical diagnostics of ethanol poisoning, alcohol abstinence, and chronic alcoholic intoxication of the mesocorticolimbic dopaminergic system remains an unresolved problem and encounters difficulties. This situation is due not only to the marked vulnerability of the neurons of the dopaminergic system but also to the fact that its mechanisms are poorly understood. The objective of the present work was to substantiate and develop diagnostic criteria for ethanol poisoning, alcohol abstinence, and chronic alcoholic intoxication of the neurons both in the mesocorticolimbic dopaminergic system and in other brain regions. The object of the study was the brain of healthy adult subjects who died from alcohol intoxication (in the period of ethanol resorption) and under conditions of alcohol abstinence (completion of the abstinence course). The purpose of the study was to elucidate factors responsible for the different degree of damage to the neurons of various identification groups (intact, hypochromic, picnomorphic, shadow) and macrogliocytes. The cells of all these types were counted at an area of 0.25 sq. mm within 4 squares each having a side of 250 mcm in length. The absolute and relative number of neurons in each group as well as the number of polyneuronal satellite cells per one intact neuron was determined. It was shown that alcohol intoxication is associated with acute swelling of and severe damage to brain neurons caused by the combination of such factors as toxic effect of ethanol, excessive production of catecholamines, and functional overstrain of dopaminergic neurons. The severity of acute alcohol damage to the neurons decreased with the distance from the mid-brain dopaminergic nuclei. Restoration of neurons during alcohol abstinence was due to compensatory activation of interactions between neurons and glial cells. It decreased in the sequence from the paranigral nucleus of the ventral portion of mesencephalic tegumentum to the medial portion of the accumbence nucleus (field 24b, layer III of field la, layer V of field 1) depending on the initial severity of acute damage in the brain region being examined. The severity of damage to the neurons of the mesocorticolimbic dopaminergic system under conditions of chronic alcohol intoxication estimated from the number of shadow neurons was similar to the degree of acute swelling associated with ethanol poisoning and decreases from a maximum in the nuclei of the mesocorticolimbic dopaminergic system to a minimum in layer III of field 1.

[Forensic medical diagnostics of the extent of the thigh skin injury inflicted by motor vehicles of different weight]

The authors report the results of an experimental study designed to characterize microstructural changes in the thigh skin caused by the impacts simulating the car wheel loads of different intensity. It was shown that histological methods can be used to discriminate between the intensities of traumatic loading on biological tissues.

Structural characteristics of neurons and macrogliocytes in interconnected regions of the mesoaccumbocingulate dopaminergic system in rats

Studies in rats (n = 6) in normal conditions addressed the morphometric parameters of neurons and macrogliocytes in the interconnected anteromedial regions of the mesoaccumbocingulate (MAC) dopaminergic system, which is important for diagnosing and identifying the morphogenesis of addiction states. A spatial model of the system was constructed which took into account the mean distance of frontal sections from the frontal pole; the densities of neurons and macrogliocytes were assessed in the central part of the paranigral nucleus of the ventral tegmental area (VTA) and the compact zone of the substantia nigra (SN) and in the interconnected anteromedial segments of these midbrain nuclei, the cingulate fields, the nucleus accumbens (NA), and layer VI of the pregenual (Cg3) and layer III of the supragenual (Cg2) cingulate fields. The anteromedial segments of the paranigral nucleus of the VTA and the compact zone of the SN, which are interconnected with these cingulate structures and the NA, contained larger numbers of neurons than the other segments, as they occupied a larger volume, while there were no differences in the volumes of neurons in the anterior and central parts of these segments. The anterior part of the compact zone of the SN also differed in having a greater neuron density. The anteromedial parts of the paranigral nucleus of the VTA and the compact zone of the SN (12.20 +/- 0.10 mm from the frontal pole) had the greatest diagnostic value in the morphological assessment of addiction because the lateral part of the paranigral nucleus of the VTA contained the largest number of non-dopaminergic neurons, while the neuron bodies of the other nuclear groups of the VTA were small in size. The medial part of the NA had its greatest volume (and, thus, number of neurons) in the central part of the nucleus (5.10 +/- 0.10 mm from the frontal pole) at the level of the anterior part of the supragenual cingulate field (Cg2). Layer VI of the pregenual cingulate field (Cg3) was most compact at the level of the base of the anterior forceps (2.40 +/- 0.10 mm from the frontal pole).

[Differential diagnosis of ethanol poisoning, alcohol withdrawal, and chronic alcoholic intoxication from the changes in neurons and macroglyocytes in the cerebral cortex]

The present paper reports results of a quantitative morphometric study of neuron and macroglyocyte populations in layers III and V of the brain somatosensory cortex in subjects with ethanol poisoning (EP), alcohol withdrawal (AW), and chronic alcoholic intoxication (CAI). The study was carried out during a more than 7-day period of abstinence in patients presenting with early manifestations of alcoholic illness. In subjects with ethanol poisoning, acute swelling of neurons in layer III was more pronounced than in layer V. Dynamic changes in the number of satellites near bodies of slightly affected neurons were recorded in layer III in patients with EP and AW as well as during the long-term break in intoxication. Layer V in EP, AW, and CAI exhibited phagocytosis of neurons, an elevated number of macroglyocytes and their enhanced proliferation along the course of blood vessels. The morphological changes of neurons and macroglyocytes under the above conditions can be categorized in terms of their degeneration rate from the beginning of the abstinence period into transient (disappearing within 7 days), persistent, and combined.

[Pathologic changes of neurons of mesocorticolimbic dopaminergic system in healthy humans and rats]

The purpose of the present study was to demonstrate pathologically changed forms of neurons and intensity of the neuronoglial interactions which represented the normal standard for the interconnected parts of mesocorticolimbic dopaminergic system (MDS) in 6 intact adult female Wistar rats and in 5 healthy humans aged 24-45 years. The percentages of unchanged, hypochromic, pyknomorphic and ghost neurons in proportion to their total number were determined in the anteromedial part of paranigral nucleus of ventral tegmental region of midbrain tegmentum (TVR), compact part of black substance (BS), anteromedial part of accumbent nucleus (NA) close to anterior brain commissure and in middle of layer III of a pregenual part of field 24b (Cg3 in rats). The structures of the brain, unrelated to MDS--layers III and V of field 1--were investigated as the control. The data obtained indicate significant changes of MDS neurons in the healthy people as compared to those in the intact rats. The number of pathologically changed MDS neurons, as well as the number of fibers in medial forebrain bundle, were shown to decrease with the increase of distance from catecholaminergic nuclei of reticular formation, reaching the minimum in non-dopaminoceptive and low-noradrenoceptive layer V of field 1. More than 25% of the neurons in TVR paranigral nucleus were ghost cells. Over 30% of NA neurons were hypochromic and ghost cells. About 25% of neurons in field 24b were ghost cells, hypochromic and pyknomorphic. The intensity of neuronoglial interaction in human and rat dopaminergic nuclei is significantly greater than in the projectional parts of MDS and in the layers of field 1, unrelated to it. Local changes of MDS neurons in man and high intensity of neuronoglial interactions in dopaminergic nuclei reflect the blurring of the boundaries between the normal state and pathology and lower durability of this system, as compared to that of the cortical fields remote from the source of catecholaminergic fibers.

[Diagnostics of alcoholic intoxication from micromorphological changes in neurons and neuroglia of the mesoaccumbocingular dopaminergic system in experiment]

Alcohol affects the mesoaccumbocingular system (ventral tegumental region, substantia nigra--nucleus accumbence--anterior cingular cortex) and other parts of the mesocorticolimbic dopaminergic system by altering patterns of dopamine release. Alcohol stimulates functioning of the nucleus accumbence involved in the formation of the additive behaviour. The function of the anterior cingular cortex responsible for the manifestations of self-sensation emotions is also enhanced under effect of alcohol-induced activation of mid-brain dopaminergic nuclei. Morphometric characteristics of neurocytes and neurogliocytes of the mesoaccumbocingular dopaminergic system revealed during acute and long-term alcohol consumption under experimental conditions can be used for micromorphological diagnosis of different variants of alcoholic intoxication, its consequences, and alcohol dependence.

[Delayed behavioral and morphological consequences in activation of the stress-antistress system in early ontogeny stages in rats]

Wistar rat pups aged 4-10-17 days were injected intraperitoneally with corticoliberin (corticotrophin-releasing hormone, CRH) in doses of 0.5 - 1.0 - 2.0 mg/rat, respectively (single administration for each rat), which activates the stress system, or with 70-kDa heat-shock protein (HSP-70) in doses of 5 - 10 - 20 mg/rat, respectively, which plays the role of intracellular shaperons and possesses antistress properties. The effect of drugs on the emotional and motor behavior was assessed in 5 tests (open field, elevated plus-maze, intruder-resident, Porsolt's depression test, and rotation test) in adult rats 90- 100-days-old. The activation of stress or antistress systems by CRH or HSP-70, respectively, changed the behavior of adult rats. These effects depended on the animal gender, being different in males and females: male rats were more sensitive in Porsolt's depression test, elevated plus-maze anxiety test, and rotation test, while being less sensitive in the open field and intruder-resident tests. These results indicate that the initial sensitivity of males and females with respect to CRH and HSP-70 is also different. The experimental data exhibited correlation with the results of morphological investigation of the limbic structures of the brain. In particular, CRH increased the relief (volume) of neurons of substantia nigra and ventral tegmental region without changing their density, while HSP-70 produced moderate degeneration of neurons and decreased their density. It is suggested the obtained data have to be taken into account in planning and conducting experimental investigations devoted to the influence of various pharmacological agents on the behavior.

[Changes in neurons and gliocytes of the rat mesoaccumbocingulate system following perinatal morphine administration]

To study the changes of neuron and gliocyte numbers and some morphometric parameters in mesoaccumbocingulate (MAC) dopaminergic system of rats after pre- and postnatal opiate treatment, 0.1 mg dose of 1% morphine hydrochloride solution was injected into the fetal amnion of Wistar female rats (n=4) at Day 17 post fertilization and intraperitoneally into newborn rats (n=4) at postnatal Day 4. Perinatal influence of morphine on MAC-system in rats resulted in the chromophilic degeneration, swelling and death of some part of neurons, decrease in the volume of the other (slightly injured) neurons. Neuronal injury was more pronounced after prenatal morphine treatment and was accompanied by the increase in both microgliocyte cell number and phagocytic activity. Morphine administration induced no changes in the satellite macrogliocyte number and in the average distance between these cells and the bodies of slightly injured neurons.

[Structural characteristics of neurons and macrogliocytes in the interconnected areas of the rat mesoaccumbocingulate dopaminergic system]

Morphometric parameters of the neurons and macrogliocytes were studied in the interconnected antero-medial areas of the mesoaccumbocingulate dopaminergic system of 6 rats under normal conditions; these data may be important for the diagnosis and elucidating of the morphogenesis of addiction conditions. The spatial model of the system was obtained which took into account an average distance of frontal sections from the frontal pole. The density of neurons and gliocytes were determined in the middle part of the paranigral nucleus of ventral tegmental area (VTA) and in substantia nigra (SN) compact part, as well as in the interconnected antero-medial parts of these midbrain nuclei, nucleus accumbens (NA), V1 layer of a pregenual (Cg3) and III layer of a supragenual (Cg2) cingulate fields. The antero-medial parts of VTA paranigral nucleus and of SN compact part, interconnected with specified cingulate structures and NA, contain more neurons than the other areas, as they occupy greater volume, while there are no differences in the volume of neurons in the anterior and in the middle parts of these structures. The anterior portion of SN compact part, besides, is remarkable for greater density of the neurons. The anteromedial parts of VTA paranigral nucleus and of SN compact part of (12.2 +/- 0.1 mm from the frontal pole) have the greatest diagnostic value for the morphological evaluation of addiction also because the lateral part of VTA paranigral nucleus contains the greatest population of a nondopaminergic neurons, while the cell bodies of the neurons of the other VTA nuclear groups are of small size. Medial part of NA has the greatest volume (and, hence, the number of neurons) in the middle of a nucleus (5.1 +/- 0.1 mm from the frontal pole) at the level of anterior part of the supragenual cingulate field (Cg2). The V1 layer of the pregenual cingulate field (Cg3) is most compact at the level of the base of anterior forceps (2.4 +/- 0.1 mm from the frontal pole).

[Rat mesoaccumbocingulate dopaminergic system and brain emotional functions]

The authors suggest to distinguish the mesoaccumbocingulate dopaminergic system within the mesocorticolimbic dopaminergic system. It defines the formation of dependence on the influence of psychoactive drugs. The cortical center of the mesoaccumbocingulate dopaminergic system--anterior cingulate fields in rats (Cg1 and Cg3)--simultaneously represents the affective and motivation-mnestic center. The affective function of the rat anterior cingulate fields after the administration of psychoactive drugs, as well as the formation of dependence on them, is associated with the distribution of the dopaminergic endings of midbrain neurons in the nucleus accumbens and at the anterior cingulate fields, in particular, in the pregenual part.

[Some aspects of the regeneration process carried out by means of pluripotent stem cells]

This work is devoted to the vital topic of regeneration by stem cells. Cells-predecessors and differentiated cells can divide a limited number of times (Alberts et al., 1994) and are not capable of providing tissue regeneration throughout the ontogenesis. The tissue renewal during such a long period is impossible without participation of a specialized system responsible for regeneration. The given system is submitted by stem cells which are capable of being differentiated in all types of somatic cells and in a line of germ cells, and also have ability to self-renew during the whole life of an organism. Results of our research suggest that stem cells make up a universal mechanism of regeneration which has been formed during evolution.

[Intercalated (basal) epitheliocytes and the regeneration of cholangiocytic epithelium in the liver]

Certain authors controversial view on intercalated (basal) cambial cells existence in enterodermal epithelia is substantiated by complex study of cells in cholangiocyte lining of interlobular bile ductules (hepatic ductules). Comprehensive explanation of mechanisms of ductules growth on cholestasis is obtained, taking into account the data concerning basal and other types of cholangiocytes.

[The structure of the terminal portions of the biliary tract of the liver and ductular hyperplasia]

It is reasonable to introduce in to the liver section of International Histological Nomenclature the term of "terminal hepatic bed" that includes interlobular bile duct, interloular (intraportal), perilobular (periportal) and intralobular bit ductules, bile canaliculus (Hering canaliculus) and bile capillary. Bile ductules and canaliculi are of the special semantic meaning in the hierarchical system of terminal biliary bed. The former may form the so-called "ductular expansions" playing compensatory-adaptive role in diverse cholestatic states. The latter are unique intercalary regions between bile capillaries of hepatic and bile ductules cholangiocytes. Hepatocyte and cholangiocyte epithelia forming the wall of terminal biliary bed--two sharply different in structure and function tissues--possess high biological tolerance in cholestasis.