The Blood−Brain Barrier in Neuroimmune Interactions and Pathological Processes

The blood–brain barrier (BBB) is a kind of filter, highly selective in relation to various types of substances. The BBB supports the immune status of the brain and is an important regulator of neuroimmune interactions. Some of the molecular and cellular features of the BBB, as well as the five main pathways of neuroimmune communication mediated by the BBB, are analyzed in this article. The functions of the BBB in neuroimmune interactions in various diseases are discussed: multiple sclerosis and Alzheimer’s and Parkinson’s diseases. The latest data on BBB dysfunction in COVID-19 coronavirus infection caused by the SARS-CoV-2 virus are considered.

Risk Factors and Mechanisms of Cardiovascular Diseases in Posttraumatic Stress Disorder Model in Wistar Rats as Dependent on Stress Resistance and Age.

The article focuses on the pathogenetic mechanisms of posttraumatic stress disorder (PTSD), which is associated with psychological stress because of the coronavirus pandemic. The molecular mechanisms responsible for disease susceptibility in some individuals and stress resistance in others are amongst crucial research interests of experimental and clinical medicine. Priority data were obtained to indicate that distortions of synthesis and metabolism and, most significantly, a switch between two energy transport forms, glucose and lipids, underlie myocardial dysfunction in young and old stress-sensitive Wistar rats in a PTSD model. Histochemistry and polarization microscopy showed energy deficit in cardiomyocytes and signs of ischemic and hypoxic areas emerging in the myocardium as a result of an accumulation of NADH and NADPH, which initiate excessive production of reactive oxygen species.

SEPSIS-3: NEW EDITION - OLD PROBLEMS. ANALYSIS FROM THE PERSPECTIVE OF GENERAL PATHOLOGY

Sepsis-3 Guidelines defines sepsis as an organ dysfunction caused by dysregulated host response to infection. To record organ dysfunction, the SOFA/quick SOFA scales were recommended. In fact, in medical practice, sepsis is considered nothing more than a critical infection that requires intensive care. Therefore, sepsis is pathogenetically a nonhomogeneous condition manifested by diverse nosologies and syndromes. Unlike the previous two editions, Sepsis-1 and Sepsis-2 Guidelines, the formal criteria provided in the Sepsis-3 are closer to the de facto position, describe more specific, but less sensitive features to predict mortality. However, the initial, latent manifestations of critical conditions, which can be relatively effectively controlled by intensive therapy, remain outside the Sepsis-3 criteria. Not all signs of multiple organ dysfunctions (according to the Sepsis-3 criteria) will require intensive care. Hence, obviously the presence or absence of formal criteria of Sepsis-3 will not be always taken into account while verifying sepsis. The only relatively pathogenetically homogeneous definition in Sepsis-3 is "septic shock". However, it also does not fully consider the staging (according to the degree of compensation of hemodynamic disturbances) and the phasing (according to the severity of the proinflammatory response) of the dynamics of the shock condition. From our point of view, a positive result of the Sepsis-3 consensus would be in transition of the systemic inflammatory response syndrome (SIRS) from the main to additional (optional) verifying sepsis criteria. We also believe that the weak side of the Sepsis-3 Guidelines is in underestimated mechanisms of systemic inflammation as a general pathological process in the genesis of developing critical conditions of various origins. From the perspective of general pathology, sepsis is a combination of the three common fundamental pathological processes: classical (canonical) and systemic inflammation (SI), as well as chronic systemic low-grade inflammation (parainflammation), the latter can be considered as an unfavorable background for development of the former two processes. All three processes are characterized by any SIR signs and require to be differentiated on the basis of integral criteria, which reflect specific blocks of the SI complex process. The pathogenesis of the SARS- CoV-2 infection (COVID-19) is a relevant example underlying inevitability of such approach. The systemic microvascular vasculitis, and its main clinical manifestations such as systemic microcirculatory disorders in the form of shockogenic conditions is the SI pathogenetic basis. Apparently, one of the modalities for further evolution of critical care medicine will be coupled to development of a more multilayered but effective methods for assessing pathogenesis of critical states and more differentiated methods of pathogenetic therapy. Therefore, it will require to modernize a number of fundamental premises in our knowledge about pathobiology, pathophysiology, and general pathology.

The Challenges of Vaccine Development against Betacoronaviruses: Antibody Dependent Enhancement and Sendai Virus as a Possible Vaccine Vector.

To design an effective and safe vaccine against betacoronaviruses, it is necessary to use their evolutionarily conservative antigenic determinants that will elicit the combination of strong humoral and cell-mediated immune responses. Targeting such determinants minimizes the risk of antibody-dependent enhancement of viral infection. This phenomenon was observed in animal trials of experimental vaccines against SARS-CoV-1 and MERS-CoV that were developed based on inactivated coronavirus or vector constructs expressing the spike protein (S) of the virion. The substitution and glycosylation of certain amino acids in the antigenic determinants of the S-protein, as well as its conformational changes, can lead to the same effect in a new experimental vaccine against SARS-CoV-2. Using more conservative structural and accessory viral proteins for the vaccine antigenic determinants will help to avoid this problem. This review outlines approaches for developing vaccines against the new SARS-CoV-2 coronavirus that are based on non-pathogenic viral vectors. For efficient prevention of infections caused by respiratory pathogens the ability of the vaccine to stimulate mucosal immunity in the respiratory tract is important. Such a vaccine can be developed using non-pathogenic Sendai virus vector, since it can be administered intranasally and induce a mucosal immune response that strengthens the antiviral barrier in the respiratory tract and provides reliable protection against infection.

[The Challenges of Vaccine Development Against Betacoronaviruses: Antibody Dependent Enhancement and Sendai Virus as a Possible Vaccine Vector].

To design an effective and safe vaccine against betacoronaviruses, it is necessary to elicit a combination of strong humoral and cell-mediated immune responses as well as to minimize the risk of antibody-dependent enhancement of viral infection. This phenomenon was observed in animal trials of experimental vaccines against SARS-CoV-1 and MERS-CoV that were developed based on inactivated coronavirus or vector constructs expressing the spike protein (S) of the virion. The substitution and glycosylation of certain amino acids in the antigenic determinants of the S-protein, as well as its conformational changes, can lead to the same effect in a new experimental vaccine against SARS-CoV-2. This review outlines approaches for developing vaccines against the new SARS-CoV-2 coronavirus that are based on non-pathogenic viral vectors. For efficient prevention of infections caused by respiratory pathogens the ability of the vaccine to stimulate mucosal immunity in the respiratory tract is important. Such a vaccine can be developed using non-pathogenic Sendai virus vector, since it can be administered intranasally and induce a mucosal immune response that strengthens the antiviral barrier in the respiratory tract and provides reliable protection against infection. The mucosal immunity and the production of IgA antibodies accompanying its development reduces the likelihood of developing an antibody-dependent infection enhancement, which is usually associated only with immunopathological IgG antibodies.