Etiologija i patogeneza ishemijske bolesti srca

Ischemic heart disease (IHD) is a condition in which there is an inadequate supply of blood and oxygen to a portion of the myocardium; it typically occurs when there is an imbalance between myocardial oxygen supply and demand. The most common cause of myocardial ischemia is atherosclerotic disease of an epicardial coronary artery (or arteries) sufficient to cause a regional reduction in myocardial blood flow and inadequate perfusion of the myocardium supplied by the involved coronary artery. Although risk factors for atherosclerosis development are largely known, the pathogenesis of disease is still matter of discussion. The investigation during the last decades have provided new date related to the role of endothelial dysfunction, and particularly role of immune cell-mediated mechanisms in pathogenesis of the disease. The data elucidating role of immunopathogenetic mechanisms in the development of atherosclerotic lesions and their complications provided a strong basis for designing a new generation of drugs to combat aterosclerosis, and thereby to prevent ischemic heart disease.Ishemijsku bolest srca karakteriše nedovoljno snabdevenje krvlju, odnosno kiseonikom, dela miokarda. Nastaje onda kada postoji nesklad između količine kiseonika koja se doprema cirkulacijom u miokard i njegovih potreba u kiseoniku. Najčešći uzrok smanjenog snabdevanja krvlju miokarda je aterosklerotska bolest jedne ili više epikardnih koronarnih arterija, koja sužava lumen i, sledstveno smanjuje. Iako su faktori rizika za razvoj ateroskleroze uglavnom poznati mehanizmi razvoja aterosklerotskih promena još uvek nisu u potpunosti razjašnjeni. Poslednje decenije donele su niz novih saznanja, vezanih za ulogu disfunkcije endotela u inicijaciji i progresiji ateroskerotskih promena i posebno za ulogu ćelija imunskog sistema i imunskih mehanizama u patogenezi ovog oboljenja. Saznanja vezana za ulogu imunopatogenetskih mehanizana stvorila su značajnu osnovu za dizajniranje nove generacije lekova za terapiju aterosklerose i time prevencu ishemijske bolesti srca

Cellular and Nerve Fibre Catecholaminergic Thymic Network: Steroid Hormone Dependent Activity

The thymus plays a critical role in establishing and maintaining the peripheral T-cell pool. It does so by providing a microenvironment within which T-cell precursors differentiate and undergo selection processes to create a functional population of major histocompatibility complex-restricted, self-tolerant T cells. These cells are central to adaptive immunity. Thymic T-cell development is influenced by locally produced soluble factors and cell-to-cell interactions, as well as by sympathetic noradrenergic and endocrine system signalling. Thymic lymphoid and non-lymphoid cells have been shown not only to express beta- and alpha(1)-adrenoceptors (ARs), but also to synthesize catecholamines (CAs). Thus, it is suggested that CAs influence T-cell development via both neurocrine/endocrine and autocrine/paracrine action, and that they serve as immunotransmitters between thymocytes and nerves. CAs acting at multiple sites along the thymocyte developmental route affect T-cell generation not only numerically, but also qualitatively. Thymic CA level and synthesis, as well as AR expression exhibit sex steroid-mediated sexual dimorphism. Moreover, the influence of CAs on T-cell development exhibits glucocorticoid-dependent plasticity. This review summarizes recent findings in this field and our current understanding of complex and multifaceted neuroendocrine-immune communications at thymic level

Immunoreactive neuropeptides in the cells of human thymus

The study was designed to explore the expression of different neuropeptides, viz. vasoactive intestinal peptide (VIP), calcitonin gene related peptide (CGRP), substance P (SP), bombesin and motilin in the cells of fetal and adult human thymus. Immunohistochemical staining revealed that cortical and medullary thymocytes were labeled by all antibodies, except those specific for motilin. Immunoreactive VIP and SP were observed in the solitary epithelial cells located in the subcapsular/subtrabecular cortex, at the corticomedullary junction and in the medulla. The cells within the subcapsular/subtrabecular monolayer, rare solitary cells in the deep cortex and epithelial cell network in the medulla, were labeled with antibodies to CGRP and bombesin. Hassall's corpuscles were labeled with all antibodies except that specific for SP. The obtained data obtained testify to the expression of different neuropeptides in human thymic lymphoid and non-lymphoid cells and suggest a role for neuroendocrine hormone-mediated mechanisms in the regulation of thymic homeostasis in humans

Differential Effects of Male and Female Gonadal Hormones on the Intrathymic T cell Maturation

The study was undertaken to further elucidate a role of gonadal hormones in maintenance of normal thymocyte maturation and sexual dimorphism in the intrathymic T-cell development. Rats of both sexes were gonadectomized or sham-gonadectomized (controls) at age of 2 and 6 months, and 30 days later the thymus size, cellularity and thymocyte composition were evaluated. In both control and gonadectomized rats, in spite of age, sexual dimorphism in the thymus size and cellularity was found. Gonadectomy in 2-month-old rats of both sexes increased the thymus cellularity, volumes of both cortex and medulla and thymus size (to a less extent in males), while in 6-month-old rats, in this respect, it was effective only in females. In ovariectomized (OVX) rats the increase in volume of cortex was more marked in younger rats, while that of medulla did not differ between rats of different age. It seems obvious that in both groups of OVX rats the volume of medullary non-lymphoid component was enlarged (the increase in medullary volume was more pronounced than that in its cellularity). Unlikely, in rats orchidectomized (ORX) at age of 2 months the volume of this component was either decreased or unaltered (the increase in the volume of medulla was less conspicuous than that in the number of medullary thymocytes). In control and gonadectomized rats of both ages, sexual dimorphism in the composition of thymocyte subsets was also observed. Gonadectomy in 2-month-old rats affected distinct stages of thymocyte maturation in male (increased the relative proportions of CD4+8+TCRαβlow cells and their CD4–8+TCRαβlow precursors and decreased those of the most mature CD4+8-TCRαβhigh and CD4–8+TCRαβhigh cells) and female rats (decreased only the percentage of the least mature CD4–8-TCRαβ-cells). In older rats only ovariectomy had impact on the relative proportion of thymocytes decreasing, besides the relative proportion of CD4–8-TCRαβ- cells, those of CD4–8+TCRαβ-, CD4–8+TCRαβlow, positively selected CD4+8+TCRαβhigh and the most mature CD4+8-TCRαβhigh, CD4–8+TCRαβhigh cells and exerting an opposite effect on the percentages of CD4+8+TCRαβ- and CD4+8+TCRαβlow cells. Thus, results showed sex- and age-dependent changes in sensitivity of both the developing thymocytes and non-lymphoid cells to long-lasting gonadal deprivation

Natural killer cells as participants in pathogenesis of rat experimental autoimmune encephalomyelitis (EAE): lessons from research on rats with distinct age and strain

Natural killer (NK) cells, influencing dendritic cell (DC)-mediated CD4+ lymphocyte priming in draining lymph nodes (dLNs) and controlling spinal cord (SC) infiltration with encephalitogenic CD4+T lymphocytes, modulate EAE (multiple sclerosis model). This study examined their putative contribution to age-related differences in EAE development in Dark Agouti (DA) (exhibiting age-related decrease in EAE susceptibility) and Albino Oxford (AO) (becoming susceptible to EAE with aging) rats. Aging increased NK cell number in dLNs from rats of both strains. In AO rats, but not in DA ones, it also increased the numbers of IFN-gamma-producing NK cells (important for DC activation) and activated/matured DCs, thereby increasing activated/matured DC/conventional Foxp3-CD4+ cell ratio and activated CD25+Foxp3-CD4+ cell number. Aging in DA rats diminished activated/matured DC/conventional Foxp3-CD4+ cell ratio and activated Foxp3-CD4+ cell number. However, MBP-stimulated CD4+ cell proliferation did not differ in dLN cell cultures from young and aged AO rats (as more favorable activated/matured DC/Foxp3-CD4+ cell ratio was abrogated by lower intrinsic CD4+ cell proliferative capacity and a greater regulatory CD25+Foxp3+CD4+ lymphocyte frequency), but was lower in those from aged compared with young DA rats. At SC level, aging shifted Foxp3-CD4+/cytotoxic CX3CR1+ NK cell ratio towards the former in AO rats, so it was less favorable in aged AO rats exhibiting prolonged neurological deficit compared with their DA counterparts. The study showed strain and age differences in number of IFN-gamma-producing NK cells in EAE rat dLNs, and suggested that their pathogenetic relevance depends on frequency and/or activity of other cells involved in CD4+ T cell (auto)immune response

Role of the End-Point Mediators of Sympathoadrenal and Sympathoneural Stress Axes in the Pathogenesis of Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis

The role of stress effector systems in the initiation and progression of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), the most commonly used experimental model of MS, has strongly been suggested. To corroborate this notion, alterations in activity of the sympathoadrenal and sympathoneural axes of sympathoadrenal system (a major communication pathway between the central nervous system and the immune system), mirrored in altered release of their end-point mediators (adrenaline and noradrenaline, respectively), are shown to precede (in MS) and/or occur during development of MS and EAE in response to immune cell activation (in early phase of disease) and disease-related damage of sympathoadrenal system neurons and their projections (in late phase of disease). To add to the complexity, innate immunity cells and T-lymphocytes synthesize noradrenaline that may be implicated in a local autocrine/paracrine self-amplifying feed-forward loop to enhance myeloid-cell synthesis of proinflammatory cytokines and inflammatory injury. Furthermore, experimental manipulations targeting noradrenaline/adrenaline action are shown to influence clinical outcome of EAE, in a disease phase-specific manner. This is partly related to the fact that virtually all types of cells involved in the instigation and progression of autoimmune inflammation and target tissue damage in EAE/MS express functional adrenoceptors. Although catecholamines exert majority of immunomodulatory effects through beta(2)-adrenoceptor, a role for alpha-adrenoceptors in EAE pathogenesis has also been indicated. In this review, we summarize all aforementioned aspects of immunopathogenetic action of catecholamines in EAE/MS as possibly important for designing new strategies targeting their action to prevent/mitigate autoimmune neuroinflammation and tissue damage

Ageing Affects Thymopoiesis and Experimental Autoimmune Encephalomyelitis Development in a Strain-Dependent Manner

INTRODUCTION: Considering significance of mechanisms of central tolerance for development of autoimmune diseases, including experimental autoimmune encephalomyelitis (EAE), and suppressive influence of circulating proinflammatory cytokines and alterations in brain-thymus communication, characteristic for the central nervous system (CNS) autoimmune diseases, on thymopoiesis, the study interogated putative strain-based thymus-related specificities relevant for the opposite effects of ageing on susceptibility of Dark Agouti (DA) and Albino Oxford (AO) rats to EAE. METHODS: Quantitative and qualitative changes in thymopoiesis including underlying mechanisms were examined using flow cytometry and RT-qPCR quantification of mRNAs for molecules relevant for integrity of stroma and T-cell development, respectively. RESULTS: With ageing, differently from DA rats, in AO rats the surface density of CD90, a negative regulator of selection threshold, on thymocytes undergoing lineage commitment was upregulated (consistent with TGF-β expression downregulation), whereas the generation of natural CD4+CD25+Foxp3+ regulatory T cells (nTregs) was impaired reflecting differences in thymic expression of cytokines supporting their development. Additionally, specifically in old AO rats, in whom EAE development depends on IL-17-producing CD8+ T cells, their thymic differentiation was augmented, reflecting augmented thymic IL-4 expression. In turn, differently from old DA rats developing self-limiting EAE, in age-matched AO rats developing EAE of prolonged duration, EAE development led to impaired generation of nTregs and accumulation of proinflammatory, cytotoxic CD28-CD4+ T cells in the periphery. DISCUSSION: The study indicates that strain differences in age-related changes in the efficacy of central tolerance, in addition to enhanced thymic generation of CD8+ T cells prone to differentiate into IL-17-producing cells, could partly explain the opposite effect of ageing on DA and AO rat susceptibility to EAE induction. Additionally, it suggested that EAE development leading to a less efficient thymic output of CD4+ cells and nTregs in old AO rats than their DA counterparts could contribute to prolonged EAE duration in AO compared with DA rats. CONCLUSION: The study warns to caution when designing therapeutic interventions to enhance thymic activity in genetically diverse populations, e.g., humans, and interpreting their outcomes. Furthermore, it indicates that CNS autoimmune pathology may additionally worsen thymic involution and age-related immune changes

Promene u modelu diferentovanja timocita u mužjaka pacova sa godinama

In order to elucidate the features of putative age-related changes in the intrathymic T cell maturation sequence, the thymus weight, thymocyte yield and relative proportions of thymocyte subsets were analyzed at distinct maturational stages (delineated by analysis of the expression of CD4/CD8 coreceptor molecules and TCR molecular complex) in male AO rats, from the peripubertal period (1 month of age) until 10 months of age. In 2-month-old rats both the thymus weight and lymphoid content were greater than in 1-month-old rats. The values of both parameters in 4-month-old rats were reduced to the corresponding values in 1-month-old rats. These levels were sustained until 10 months of age. However, the thymocyte composition was subjected to substantial changes during the whole period studied, probably due to alterations in action of both extrinsic and intrinsic factors which influence the ability of the thymus to support T cell maturation and/or feedback regulatory action of intrathymic CD4+ T cells on thymocytopoiesis (between the age of 7 and 10 months).U cilju definisanja karakteristika procesa sazrevanja T ćelija u timusu u funkciji uzrasta, u mužjaka pacova AO soja, različitog uzrasta (od 1 meseca do 10 meseci) posmatrane su: težina timusa, ukupan broj timocita, kao i relativna zastupljenost pojedinih timocitnih subpopulacija (koje su razdvojene na osnovu ekspresije CD4/8 koreceptornih molekula i antigena TCRαβ molekulskog kompleksa). U životinja uzrasta 2 meseca i težina timusa i ukupan broj timocita bili su značajno veći nego u životinja uzrasta od mesec dana. Međutim, u životinja uzrasta od 4 meseca vrednost ovih parametra nije se razlikovala od vrednosti odgovarajućih parametara sa mesec dana. Vrednosti oba ova parametra nisu se bitno menjale od 4. do 10. meseca života. Sa druge strane, naši rezultati su pokazali značajne promene u relativnom odnosu timocitnih subpopulacija u ispitivanom periodu. Ove promene se mogu objasniti promenama u delovanju, kako spoljašnjih tako i unutrašnjih, faktora koji modulišu sposobnost timusne mikrosredine da podrži proces sazrevanja T ćelija i/ili utiču na efikasnost regulatornog delovanja intratimusnih CD4+ T ćelija, mehanizmom negativne povratne sprege, na proces sazrevanja T ćelija u timusu

Propranolol diminished severity of rat EAE by enhancing immunoregulatory/protective properties of spinal cord microglia

Sympathetic dysfunction is suggested to contribute to development of multiple sclerosis and experimental autoimmune encephalomyelitis (EAE) alike. Considering important role of microglia in development/resolution of neuroinflammation, contribution of noradrenaline, the key sympathetic end-point mediator, in modulation of microglial phenotypic and functional properties in rat EAE model was examined. The study showed that noradrenaline acting in neurocrine and autocrine/paracrine way might influence microglia during EAE. Propranolol treatment over the effector phase moderated EAE course. This was associated with the increased proportion of microglia expressing CX3CR1, the key molecule in their immunomodulatory/neuroprotective action, and up regulation of CX3CR1 downstream Nrf2 gene. This correlated with the increased heme oxygenase-1 (HO-1) expression and phagocytic capacity of microglia, and their phenotypic changes mirrored in increased proportion of CD163- and CD83-expressing cells. The enhanced HO-1 expression was linked with the decreased proportion of microglial cells expressing IL-1 beta and IL-23, and possibly IL-6, followed by increased proportion of IL-10 expressing microglia, and downregulated MCP-1/CCL2 expression. Consistently, spinal cord infiltration with blood-borne myeloid and CD4 + T cells, as well as CD4 + T-cell reactivation/proliferation and differentiation into highly pathogenic IL-17 + cells co-producing IFN-gamma and GM-CSF were decreased in propranolol-treated rats compared with saline-injected controls. The in vitro investigations of the effects of noradrenaline on microglia showed that noradrenaline through beta-adrenoceptor may influence Nrf2 expression also via CX3CR1-independent route. The study suggests beta-adrenoceptor-mediated neuroinflammation-promoting role of noradrenaline in EAE via modulation of microglial Nrf2 expression, and thereby forms the basis for further translational pharmacological research to improve multiple sclerosis therapy