Hematopoiesis during Ontogenesis, Adult Life, and Aging

In the bone marrow of vertebrates, two types of stem cells coexist—hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). Hematopoiesis only occurs when these two stem cell types and their descendants interact. The descendants of HSCs supply the body with all the mature blood cells, while MSCs give rise to stromal cells that form a niche for HSCs and regulate the process of hematopoiesis. The studies of hematopoiesis were initially based on morphological observations, later extended by the use of physiological methods, and were subsequently augmented by massive application of sophisticated molecular techniques. The combination of these methods produced a wealth of new data on the organization and functional features of hematopoiesis in the ontogenesis of mammals and humans. This review summarizes the current views on hematopoiesis in mice and humans, discusses the development of blood elements and hematopoiesis in the embryo, and describes how the hematopoietic system works in the adult organism and how it changes during aging.

DYNAMICS OF ENZYME ACTIVITY AND SOME BLOOD ELEMENTS IN SHEEP PARASITOSIS

The article presents some studies on study of some aspects of pathogenesis in associative parasitosis of gas-trointestinal tract of sheep. As a result of the conducted studies, it was found that during spontaneous invasion of sheep by associations of parasites of gastrointestinal tract, following changes were established: a significant decrease in number of red blood cells by 1,77 times (P<0,001), hemoglobin-by 39,86 % (P<0,001), an increase in alanineaminotransferase and aspartateaminotransferase – by 1,59 times (P<0,01) and 1,42 times (P<0,001), alkaline phosphatase – by 1,32 times (P<0,001).

Blood cell adhesion to arterial filters analysis by scanning electron microscopy and real-time PCR assay: observational clinical study in cardiac surgery patients

Introduction: Arterial filter is the part of the cardiopulmonary bypass circuit where blood cells are exposed to high mechanical stress and where cellular aggregates may fasten in large quantities. The aim of this study was to analyse blood cell adhesiveness in the arterial filter through scanning electron microscopy and real-time PCR assay. Methods: Prospective, clinical and observational study performed on 28 patients undergoing cardiac surgery with cardiopulmonary bypass. Arterial filters were analysed by scanning electron microscopy. Real-time PCR assay was performed in extracted material from the arterial filters for analysis of platelet GPIb and CD45 leucocyte gene expression. Blood coagulation was analysed during cardiopulmonary bypass. Patients were followed until hospital discharge or 28 days after surgery. Results: All studied arterial filters used in the subject patients showed a degree of adhesion from blood elements at scanning electron microscopy. All studied filters were positive for platelets GPIb gene expression and 15% had CD45 leucocyte gene expression. The GPIb platelet gene expression in blood lowered at the end of cardiopulmonary bypass ( p = 0.019). There was negative correlation between blood GPIb platelet gene expression and Clot SR (HEPSCREEN2 ReoRox®) (rho = 0.635; p = 0.027). The filter fields count was correlated to the D-dimer dosage (rho = 0.828; p < 0.001). Conclusion: There was adhesion of blood elements, especially nucleated platelets, on all arterial filters studied. Although the arterial filter worked as a safety device, that possibly prevented arterial embolisation, it may also have caused greater hyperfibrinolysis during cardiopulmonary bypass.

CD31 Mimetic Coating Enhances Flow Diverting Stent Integration into the Arterial Wall Promoting Aneurysm Healing

Background and Purpose: Beyond aneurysmal occlusion, metallic flow diverters (FDs) can induce an adverse endovascular reaction due to the foreignness of metal devices, hampering FD endothelialization across the aneurysm neck, and arterial healing of intracranial aneurysms. Here, we evaluated the potential benefits of an FD coating mimicking CD31, a coreceptor critically involved in endothelial function and endovascular homeostasis, on the endothelialization of FDs implanted in vivo. Methods: Nitinol FD (Silk Vista Baby) and flat disks were dip-coated with a CD31-mimetic peptide via an intermediate layer of polydopamine. Disks were used to assess the reaction of endothelial cells and blood elements in vitro. An aneurysm rabbit model was used to compare in vivo effects on the arterial wall of CD31-mimetic–coated (CD31-mimetic, n=6), polydopamine-coated (polydopamine, n=6), and uncoated FDs (bare, n=5) at 4 weeks post-FD implantation. In addition, long-term safety was assessed at 12 weeks. Results: In vitro, CD31-mimetic coated disks displayed reduced adhesion of blood elements while favoring endothelial cell attachment and confluence, compared to bare and polydopamine disks. Strikingly, in vivo, the neoarterial wall formed over the CD31-mimetic-FD struts at the aneurysm neck was characteristic of an arterial tunica media, with continuous differentiated endothelium covering a significantly thicker layer of collagen and smooth muscle cells as compared to the controls. The rates of angiographic complete occlusion and covered branch arterial patency were similar in all 3 groups. Conclusions: CD31-mimetic coating favors the colonization of metallic endovascular devices with endothelial cells displaying a physiological phenotype while preventing the adhesion of platelets and leukocytes. These biological properties lead to a rapid and improved endothelialization of the neoarterial wall at the aneurysm neck. CD31-mimetic coating could therefore represent a valuable strategy for FD biocompatibility improvement and aneurysm healing.

ANALYSIS OF FORMING BLOOD ELEMENTS USING SURFACE PLASMON-POLARITON RESONANCE: MODEL OF TRANSITION LAYER

Despite the great practical importance, the control of blood by optical methods is enormously complicated by the strong scattering of light. This is especially true for formed blood elements (FBEs), which are a compact suspension that remains after plasma removal from blood by centrifugation. The study of the surface plasmon resonance (SPR) in Kretchman’s geometry together with measurement of the angular dependence of the light internal reflection R( φ ) at the glass/ FBEs boundary is one of the few possibilities to obtain additional information about the structure and molecular composition of this complex inhomogeneous object. Measurement of R( φ ) for contact FBEs with the glass surface allows to determine the total internal reflection (TIR) angle and the effective refractive index N of the binary of erythrocytes-blood plasma mixture. At the same time, the comparison of the angles of TIR and SPR makes it possible to establish the presence of a transition layer between gold surface and the volume of FBEs. In addition, a detailed matching of the experimental dependence R( φ ) with one of calculated curve by regression method allows minimize the objective function and allows to establish a detailed model of the transition layer. The paper shows that the value of N is 1.4003...1.4008. According to the formula of the effective Bruggeman's medium, the packing density of erythrocytes in the volume of FBEs is about 85%, which is well matched with the data known from the literature. At the same time, at least two intermediate layers were detected at the gold /FBEs interface. (1) A layer 33–38 nm thick adjacent to the hydrophobic surface of the gold film and with a refractive index of N p = 1.356–1.357. Presumably, it is a binary phase with a liquid part in the form of water, a buffer solution or blood plasma and a hard part in the form of proteins non-specifically related to gold, most likely molecules of albumin and fibrinogen. (2) A thicker, transition-to- volume FBEs layer is most likely related to the edges curvature and marginal packing of erythrocytes; the effective thickness of this layer is d m = 130-200 nm, and the effective refractive index N m = 1.356... 1.369. The details of this transition layer are currently of considerable practical interest because they can reflect the physiological state of blood cells and whole body, and the parameters d m and N m can be useful from a biological or medical point of view.

Plasma replacement solutions in the intensive care unit of shock for acute spontaneous canine babesiosis

The article presents the results of studies on the study of secondary processes that develop during acute spontaneous babesiosis in dogs, as well as on the use of infusion therapy with plasma substitutes for the development of shock as a complication of the underlying disease. It is shown that acute blood parasitic disease is accompanied by the development of moderate subcompensated shock, which determines the state of unstable equilibrium and the tendency to avalanche-like disorders due to the transition of the process to the decompensated phase. The basis for the diagnosis of the shock state was the establishment of the following hemodynamic and hemorheological changes: hypovolemia with a decrease of all blood components (shaped elements and plasma components) in the circulation, a significant decrease in the specific volume of circulating blood, hematocrit value, a significant increase in spontaneous aggregation of shaped blood elements (platelets and red blood cells), hypotension, an increase in the Alghöver shock index by almost 2 times. There was a significant deficit in the volume of circulating blood (the degree of blood loss), which was about 30 %. It is shown that the presence of a state of shock in the subcompensation stage poses a threat to the life of the animal in the event of transition to the terminal stage. In order to stop the development of shock, infusion therapy was used with the most common plasma–substituting solutions – Rheopolyglucin and Rheosorbylact at a dose of 5 ml/kg of body weight intravenously drip per day for 3 days. A comparative assessment of the effect of drugs on the correction of major hemodynamic and hemorheological shifts was carried out. It was found that Rheopolyglucin as a colloidal plasma substitute has a better effect on the normalization of hemodynamic disorders – hypovolemia and hypotension, and Rheosorbylact as a crystalloid plasma substitute turned out to be the best disaggregant and reducing agent of hemorheological disorders. Both drugs provided a complete recovery of hemodynamic and hemorheological parameters in 72 hours. As a result, it is recommended to use a combination of drugs with the priority of Rheopolyglucin in the first hours of treatment and combine it with an infusion of Rheosorbylact in subsequent days.

LABORATORY PREDICTORS OF GLAUCOMA IN PATIENTS WITH MIDDLE AND OLD AGE - A TOOL TO IMPROVE THE QUALITY OF LIFE (LITERATURE REVIEW)

В мире насчитывается около 1,3 млрд человек с такими нарушениями зрительного анализатора, как катаракта и глаукома, распространенность которых значимо выше у лиц пожилого возраста. Заболевания глаз остаются глобальной медикосоциальной и экономической проблемой, что связано как с прогрессированием болезни вплоть до слепоты, так и с отсутствием методов патогенетической терапии. Вторичной профилактикой глаукомы остается своевременное выявление патологии. В настоящее время разработан ряд диагностических приемов, включающих, в основном, инструментальные методики. Несомненно, в качестве скрининговых методов донозологической диагностики могут выступать лабораторные показатели. Сегодня выявлена группа биомаркеров, обладающих разной степенью чувствительности и специфичности. Однако широкое использование индикации данных маркеров затруднено, в том числе и по организационным причинам. Встает вопрос поиска следов присутствия патологии в таких рутинных исследованиях, как общий анализ крови. Глаукома признана системным заболеванием, что может найти отражение в изменении морфофункциональных свойств форменных элементов крови. There are about 1,3 billion people worldwide with visual disorders such as cataract and glaucoma, the prevalence of which is significantly higher in elder persons. Eye diseases remain a global medical, social and economic problem, associated with both the progression of the disease up to blindness and the lack of pathogenetic therapy methods. Timely detection of pathology is secondary prevention of glaucoma. At present, a number of diagnostic techniques have been developed, including mainly instrumental techniques. Undoubtedly, laboratory indicators should be used as screening methods of early diagnosis. Today, a group of biomarkers with different degrees of sensitivity and specificity has been identified. However, these markers have some difficulty in indicating. Finding signs of glaucoma in complete blood count is an important task. Glaucoma is recognized as a systemic disease, which should be reflected in the change in morphofunctional properties of blood elements.

Ticagrelor Prevents Endothelial Cell Apoptosis through the Adenosine Signalling Pathway in the Early Stages of Hypoxia

Background: Several studies have reported the beneficial effects of anti-platelet drugs in cardioprotection against ischaemia–reperfusion injuries. To date, no studies have focused on the indirect cytoprotective effects of ticagrelor via adenosine receptor on the endothelium. Method: By evaluating cell viability and cleaved caspase 3 expression, we validated a model of endothelial cell apoptosis induced by hypoxia. In hypoxic endothelial cells treated with ticagrelor, we quantified the extracellular concentration of adenosine, and then we studied the involvement of adenosine pathways in the cytoprotective effect of ticagrelor. Results: Our results showed that 10 µM ticagrelor induced an anti-apoptotic effect in our model associated with an increase of extracellular adenosine concentration. Similar experiments were conducted with cangrelor but did not demonstrate an anti-apoptotic effect. We also found that A2B and A3 adenosine receptors were involved in the anti-apoptotic effect of ticagrelor in endothelial cells exposed to 2 h of hypoxia stress. Conclusion: we described an endothelial cytoprotective mechanism of ticagrelor against hypoxia stress, independent of blood elements. We highlighted a mechanism triggered mainly by the increased extracellular bioavailability of adenosine, which activates A2B and A3 receptors on the endothelium.