[Spectrofluorimetric changes in the lens after intravitreal injections of brolucizumab]

Intravitreal injections (IVI) of vascular endothelial growth factor (VEGF) inhibitors are actively used in the treatment of various ophthalmic pathologies. In addition to the pronounced therapeutic effect of anti-VEGF drugs described in the literature, a number of data on adverse effects associated with the use of IVI, including from the lens, have now been accumulated. Prevention of possible side effects of this type of treatment requires further investigation.

PURPOSE

The study evaluates the changes in spectrofluorometric parameters of the lens after intravitreal injections of brolucizumab in eyes with native lens.

MATERIAL AND METHODS

The study included 13 people with neovascular age-related macular degeneration (AMD) who received IVI of brolucizumab. All patients were over 40 years old; changes in central retinal thickness in the macular area exceeded 300 μm according to optical coherence tomography. Spectrofluorimetric indicators of the lens were studied before and after injections of the drug in both eyes. The spectra were analyzed in the wavelength range 412-698 nm to record the changes in the content of non-tryptophan fluorophore molecules in the lens.

RESULTS

Spectrofluorimetry revealed metabolic changes in the native lens after intravitreal injections of the drug brolucizumab. No such changes were observed in the lens of the eyes not injected with the drug (the «Control» group). The proposed investigation technique involves prospective assessment of the safety of various molecules injected intravitreally in terms of cataract development at various times after the injection.

CONCLUSION

Spectrofluorimetry can be used for identifying initial metabolic changes in the lens. It is a promising method for assessing the molecules used in intravitreal injections in terms of their safety for the native lens, as well as for development of detailed instructions for clinically substantiated use of drugs with adverse effects in the form of cataract induction. According to spectrofluorimetry, IVI of the drug brolucizumab affects metabolic changes in the lens.

[Plasma acid reproduces oxidative and nitrosative stress in bladder tissue in vitro: experimental study]

AIM

To analyze some effects of plasma acid in vitro on the bladder tissue obtained from laboratory animals and to evaluate the possibility of its application for in vitro modeling of IC/BPS.

MATERIALS AND METHODS

The tissue samples of the bladder wall were obtained from female Wistar rats aged 3 months (n=16, weighing 180-200 g). The tissues were processed for 1 hour in the plasma acid prepared by spark discharge of water for injection in air. The immunohistochemical study of obtained samples was performed.

RESULTS

The changes in the expression profile of bladder epithelial cells under the action of plasma acid in vitro were found indicating the development of oxidative, nitrosative and dicarbonyl stress, impaired expression of NADPH oxidase DUOX2 and VEGF, and a decrease in cell proliferative activity, which, in general, corresponds to the main mechanisms of urothelial alterations specific for the IC/BPS.

CONCLUSION

The revealed effects of plasma acid on bladder epithelial cells confirm the possibility of using it as an inducer of urothelial cell damage typical for IC/BPS in the in vitro models.

[Atmospheric reactive oxygen species and some aspects of the antiviral protection of the respiratory epithelium]

The review focuses on molecular and biochemical mechanisms of nonspecific protection of respiratory epithelium. The authors provide a comprehensive analysis of up-to-date data on the activity of the lactoperoxidase system expressed on the surface of the respiratory epithelium which provides the generation of hypothiocyanate and hypoiodite in the presence of locally produced or inhaled hydrogen peroxide. Molecular mechanisms of production of active compounds with antiviral and antibacterial effects, expression profiles of enzymes, transporters and ion channels involved in the generation of hypothiocyanite and hypoiodate in the mucous membrane of the respiratory system in physiological and pathological conditions (inflammation) are discussed. In the context of antibacterial and antiviral defense special attention is paid to recent data confirming the effects of atmospheric air composition on the efficiency of hypothiocyanite and hypoiodate synthesis in the respiratory epithelium. The causes and outcomes of lactoperoxidase system impairment due to the action of atmospheric factors are discussed in the context of controlling the sensitivity of the epithelium to the action of bacterial agents and viruses. Restoration of the lactoperoxidase system activity can be achieved by application of pharmacological agents aimed to compensate for the lack of halides in tissues, and by the control of chemical composition of the inhaled air.

Blood-Brain Barrier and Neurovascular Unit In Vitro Models for Studying Mitochondria-Driven Molecular Mechanisms of Neurodegeneration

Pathophysiology of chronic neurodegeneration is mainly based on complex mechanisms related to aberrant signal transduction, excitation/inhibition imbalance, excitotoxicity, synaptic dysfunction, oxidative stress, proteotoxicity and protein misfolding, local insulin resistance and metabolic dysfunction, excessive cell death, development of glia-supported neuroinflammation, and failure of neurogenesis. These mechanisms tightly associate with dramatic alterations in the structure and activity of the neurovascular unit (NVU) and the blood-brain barrier (BBB). NVU is an ensemble of brain cells (brain microvessel endothelial cells (BMECs), astrocytes, pericytes, neurons, and microglia) serving for the adjustment of cell-to-cell interactions, metabolic coupling, local microcirculation, and neuronal excitability to the actual needs of the brain. The part of the NVU known as a BBB controls selective access of endogenous and exogenous molecules to the brain tissue and efflux of metabolites to the blood, thereby providing maintenance of brain chemical homeostasis critical for efficient signal transduction and brain plasticity. In Alzheimer's disease, mitochondria are the target organelles for amyloid-induced neurodegeneration and alterations in NVU metabolic coupling or BBB breakdown. In this review we discuss understandings on mitochondria-driven NVU and BBB dysfunction, and how it might be studied in current and prospective NVU/BBB in vitro models for finding new approaches for the efficient pharmacotherapy of Alzheimer's disease.

[Effect of sliding discharge on proliferation and death of brain microvessel endothelial cells in vitro]

The dose-dependent effects of plasma exposure to a unipolar nanosecond sliding discharge over the surface of the culture medium in a closed plate on the cells of cerebral endothelium in vitro were studied. Using a 24-well plate, the surface plasma energy density of one pulse was 360 μJ/cm2 at a pulse frequency of 100 Hz. It has been shown that in the creeping discharge plasma there is an active excitation of air molecules, the formation of positive nitrogen and oxygen ions, and the formation of carbon monoxide. In the dose density range of 0-32 J/cm2, the dose-dependent effects were assessed in the 4-12 h post-radiation period. Cell death was analyzed with an assessment of the total number of cells, necrotic cells, cells in apoptosis (phosphatidylserine externalization, internucleosomal DNA fragmentation) and their proliferative activity (Ki67-immunopositive cells). A preliminary assessment of subtle dose-dependent effects indicates the peculiarities of the effect of small doses.

Current approaches to modeling the virtual reality in rodents for the assessment of brain plasticity and behavior

Virtual reality (VR) and augmented reality (AR) have become valuable tools to study brains and behaviors resulting in development of new methods of diagnostics and treatment. Neurodegenerаtion is one of the best examples demonstrating efficacy of VR/АR technologies in modern neurology. Development of novel VR systems for rodents and combination of VR tools with up-to-date imaging techniques (i.e. MRI, imaging of neural networks etc.), brain electrophysiology (EEG, patch-clamp), precise analytics (microdialysis) allowed implementing of VR protocols into the animal neurobiology to study brain plasticity, sensorimotor integration, spatial navigation, memory, and decision-making. VR/AR for rodents is а young field of experimental neuroscience and has already provided more consistent testing conditions, less human-animal interaction, opportunities to use a wider variety of experimental parameters. Here we discuss present and future perspectives of using VR/AR to assess brain plasticity, neurogenesis and complex behavior in rodent and human study, and their advantages for translational neuroscience.

Plasticity of Adipose Tissue-Derived Stem Cells and Regulation of Angiogenesis

Adipose tissue is recognized as an important organ with metabolic, regulatory, and plastic roles. Adipose tissue-derived stem cells (ASCs) with self-renewal properties localize in the stromal vascular fraction (SVF) being present in a vascular niche, thereby, contributing to local regulation of angiogenesis and vessel remodeling. In the past decades, ASCs have attracted much attention from biologists and bioengineers, particularly, because of their multilineage differentiation potential, strong proliferation, and migration abilities in vitro and high resistance to oxidative stress and senescence. Current data suggest that the SVF serves as an important source of endothelial progenitors, endothelial cells, and pericytes, thereby, contributing to vessel remodeling and growth. In addition, ASCs demonstrate intriguing metabolic and interlineage plasticity, which makes them good candidates for creating regenerative therapeutic protocols, in vitro tissue models and microphysiological systems, and tissue-on-chip devices for diagnostic and regeneration-supporting purposes. This review covers recent achievements in understanding the metabolic activity within the SVF niches (lactate and NAD+ metabolism), which is critical for maintaining the pool of ASCs, and discloses their pro-angiogenic potential, particularly, in the complex therapy of cardiovascular and cerebrovascular diseases.

Designing in vitro Blood-Brain Barrier Models Reproducing Alterations in Brain Aging

Blood-brain barrier (BBB) modeling in vitro is a huge area of research covering study of intercellular communications and development of BBB, establishment of specific properties that provide controlled permeability of the barrier. Current approaches in designing new BBB models include development of new (bio) scaffolds supporting barriergenesis/angiogenesis and BBB integrity; use of methods enabling modulation of BBB permeability; application of modern analytical techniques for screening the transfer of metabolites, bio-macromolecules, selected drug candidates and drug delivery systems; establishment of 3D models; application of microfluidic technologies; reconstruction of microphysiological systems with the barrier constituents. Acceptance of idea that BBB in vitro models should resemble real functional activity of the barrier in different periods of ontogenesis and in different (patho) physiological conditions leads to proposal that establishment of BBB in vitro model with alterations specific for aging brain is one of current challenges in neurosciences and bioengineering. Vascular dysfunction in the aging brain often associates with leaky BBB, alterations in perivascular microenvironment, neuroinflammation, perturbed neuronal and astroglial activity within the neurovascular unit, impairments in neurogenic niches where microvascular scaffold plays a key regulatory role. The review article is focused on aging-related alterations in BBB and current approaches to development of “aging” BBB models in vitro.

Gliotransmitters and cytokines in the control of blood-brain barrier permeability

The contribution of astrocytes and microglia to the regulation of neuroplasticity or neurovascular unit (NVU) is based on the coordinated secretion of gliotransmitters and cytokines and the release and uptake of metabolites. Blood-brain barrier (BBB) integrity and angiogenesis are influenced by perivascular cells contacting with the abluminal side of brain microvessel endothelial cells (pericytes, astrocytes) or by immune cells existing (microglia) or invading the NVU (macrophages) under pathologic conditions. The release of gliotransmitters or cytokines by activated astroglial and microglial cells is provided by distinct mechanisms, affects intercellular communication, and results in the establishment of microenvironment controlling BBB permeability and neuroinflammation. Glial glutamate transporters and connexin and pannexin hemichannels working in the tight functional coupling with the purinergic system serve as promising molecular targets for manipulating the intercellular communications that control BBB permeability in brain pathologies associated with excessive angiogenesis, cerebrovascular remodeling, and BBB-mediated neuroinflammation. Substantial progress in deciphering the molecular mechanisms underlying the (patho)physiology of perivascular glia provides promising approaches to novel clinically relevant therapies for brain disorders. The present review summarizes the current understandings on the secretory machinery expressed in glial cells (glutamate transporters, connexin and pannexin hemichannels, exocytosis mechanisms, membrane-derived microvesicles, and inflammasomes) and the role of secreted gliotransmitters and cytokines in the regulation of NVU and BBB permeability in (patho)physiologic conditions.

Blood-brain barrier-supported neurogenesis in healthy and diseased brain

Adult neurogenesis is one of the most important mechanisms contributing to brain development, learning, and memory. Alterations in neurogenesis underlie a wide spectrum of brain diseases. Neurogenesis takes place in highly specialized neurogenic niches. The concept of neurogenic niches is becoming widely accepted due to growing evidence of the important role of the microenvironment established in the close vicinity to stem cells in order to provide adequate control of cell proliferation, differentiation, and apoptosis. Neurogenic niches represent the platform for tight integration of neurogenesis and angiogenesis supported by specific properties of cerebral microvessel endothelial cells contributing to establishment of partially compromised blood-brain barrier (BBB) for the adjustment of local conditions to the current metabolic needs of stem and progenitor cells. Here, we review up-to-date data on microvascular dynamics in activity-dependent neurogenesis, specific properties of BBB in neurogenic niches, endothelial-driven mechanisms of clonogenic activity, and future perspectives for reconstructing the neurogenic niches in vitro.

Differential Roles of Environmental Enrichment in Alzheimer's Type of Neurodegeneration and Physiological Aging

Impairment of hippocampal adult neurogenesis in aging or degenerating brain is a well-known phenomenon caused by the shortage of brain stem cell pool, alterations in the local microenvironment within the neurogenic niches, or deregulation of stem cell development. Environmental enrichment (EE) has been proposed as a potent tool to restore brain functions, to prevent aging-associated neurodegeneration, and to cure neuronal deficits seen in neurodevelopmental and neurodegenerative disorders. Here, we report our data on the effects of environmental enrichment on hippocampal neurogenesis in vivo and neurosphere-forming capacity of hippocampal stem/progenitor cells in vitro. Two models - Alzheimer's type of neurodegeneration and physiological brain aging - were chosen for the comparative analysis of EE effects. We found that environmental enrichment greatly affects the expression of markers specific for stem cells, progenitor cells and differentiated neurons (Pax6, Ngn2, NeuroD1, NeuN) in the hippocampus of young adult rats or rats with Alzheimer's disease (AD) model but less efficiently in aged animals. Application of time-lag mathematical model for the analysis of impedance traces obtained in real-time monitoring of cell proliferation in vitro revealed that EE could restore neurosphere-forming capacity of hippocampal stem/progenitor cells more efficiently in young adult animals (fourfold greater in the control group comparing to the AD model group) but not in the aged rats (no positive effect of environmental enrichment at all). In accordance with the results obtained in vivo, EE was almost ineffective in the recovery of hippocampal neurogenic reserve in vitro in aged, but not in amyloid-treated or young adult, rats. Therefore, EE-based neuroprotective strategies effective in Aβ-affected brain could not be directly extrapolated to aged brain.

Endothelial Progenitor Cells Physiology and Metabolic Plasticity in Brain Angiogenesis and Blood-Brain Barrier Modeling

Currently, there is a considerable interest to the assessment of blood-brain barrier (BBB) development as a part of cerebral angiogenesis developmental program. Embryonic and adult angiogenesis in the brain is governed by the coordinated activity of endothelial progenitor cells, brain microvascular endothelial cells, and non-endothelial cells contributing to the establishment of the BBB (pericytes, astrocytes, neurons). Metabolic and functional plasticity of endothelial progenitor cells controls their timely recruitment, precise homing to the brain microvessels, and efficient support of brain angiogenesis. Deciphering endothelial progenitor cells physiology would provide novel engineering approaches to establish adequate microfluidically-supported BBB models and brain microphysiological systems for translational studies.

Current advances in cell electrophysiology: applications for the analysis of intercellular communications within the neurovascular unit

Patch clamp is a golden standard for studying (patho)physiological processes affecting membranes of excitable cells. This method is rather labor-intensive and requires well-trained professionals and long-lasting experimental procedures; therefore, accurate designing of the experiments with patch clamp methodology as well as collecting and analyzing the data obtained are essential for the widely spread implementation of this method into the routine research practice. Recently, the method became very prospective not only for the characterization of single excitable cells but also for the detailed assessment of intercellular communication, i.e. within the neurovascular unit. Here, we analyze the main advantages and disadvantages of patch clamp method, with special focus on the tendencies in clamping technique improvement with the help of patch electrodes for the assessment of intercellular communication in the brain.

[PHARMACOLOGICAL CARDIOPROTECTION DURING REPERFUSION OF ISOLATED HEART]

PURPOSE

To study the contractile function, the degree of damage and regional myocardial metabolism in the isolated rat heart model subjected to cardioplegic stop and reperfusion under the protection of levosimendan.

MATERIALS AND METHODS

The study was performed on isolated rat hearts Wistar (group using "Custodiol" vs group using "Custodiol" + "Levosimendan". We assessed the extent of myocardial damage (in terms of markers of myocardial necrosis), the contractile function of the myocardium (coronary flow, heart rate, left ventricular pressure), the dynamics of redox processes during reperfusion with a parallel study of histology of the myocardium.

RESULTS

We found a presence of cardioprotective effect of levosimendan in respect of the isolated heart in the reperfusion period of cardioplegic ischemia. The effect related to reducing the emission of reperfusion enzyme markers of myocardial damage, reducing the severity of pathological changes in the myocardium and reducing the intensity of free radical reactions in the myocardium.

CONCLUSIONS

Cardioprotection with levosimendan reduces the severity of free radical attack the isolated heart, reduces the severity of damage to cardiomyocytes and preserves the contractile activity of the myocardium during reperfusion due to the effect of postconditioning.

Results of an experimental study of the UV radiation effect on the photosensitive skin protein

TsPO (18 kDa translocator protein) is a photosensitive protein regulating processes of skin proliferation and apoptosis. Changes in the conformational properties of TsPO correlate with the intensity of cell proliferation. Changes in the TsPO level in the ratsskin after exposure to UV radiation were assessed with the use of immunohistochemical staining. It was revealed that the dose of 200 J/m2 causes a unidirectional increase in the TsPO and PCNA (a cell proliferation marker) levels in the skin. UV radiation in the doses of 400-600 J/m2 induces a reduction of TsPO and PCNA expression. Thus, there is a possibility that TsPO participates in the regulation of changes in the intensity of cell proliferation in the skin under the exposure to UV radiation.

[The role of P2X7 receptors in modulation of the functional activity of peritoneal macrophages in mice with peritonitis]

The role of P2X7 receptors in modulation of the functional activity of macrophages in mice with model peritonitis has been studied. It is established that the functional activity of murine macrophages under such conditions is increased, which is accompanied by the growth of P2X7(+) macrophages and a bidirectional change of the their functional activity under the action of P2X7 modulators. The role of P2X7-associated mechanisms in regulation of the macrophage activity during inflammation is discussed.

Modification of membrane-toxic effect of Nd-YAG laser by preliminary induction of cytochrome P-450 in bone marrow cells

The cytotoxic effects of Nd-YAG laser with a wavelength of 533 nm were studied in mouse bone marrow cells in vitro. Laser exposure caused blebbing of bone marrow cell plasma membrane. Preliminary induction of cytochrome P-450 with 3-methylcholanthrene modified the cytotoxic effect of Nd-YAG laser.

[The effect of N2-laser radiation on the kinetics of the generation of active forms of oxygen by the granulocytic-macrophagal cells in a whole-blood system]

The report deals with the study on the kinetics of the generation of the reactive oxygen forms (ROF) by granulocyte-macrophage cells (GMC) in the whole blood. It was shown that the energy of N2-laser radiation promotes the modulation effect of the ROF generation. Its biological significance can be connected with the correction of GMC's functional activity. We suppose that the mechanism of the modulation effect of the ROF production induced by N2-laser radiation connected with the triggering role of NADP(H), the key molecule of "respiratory burst", which absorbs the light of 337 nm, N2-laser emission wavelength.