[Epithelial protective therapy in comorbid diseases. Practical Guidelines for Physicians].

This document was produced with the support of the National Medical Association for the Study of Comorbidities (NASС). In 2021 the first multidisciplinary National Consensus on the pathophysiological and clinical aspects of Increased Epithelial Permeability Syndrome was published. The proposed guidelines are developed on the basis of this Consensus, by the same team of experts. Twenty-eight Practical Guidelines for Physicians statements were adopted by the Expert Council using the "delphic" method. Such main groups of epithelial protective drugs as proton pump inhibitors, bismuth drugs and probiotics are discussed in these Guidelines from the positions of evidence-based medicine. The clinical and pharmacological characteristics of such a universal epithelial protector as rebamipide, acting at the preepithelial, epithelial and subepithelial levels, throughout gastrointestinal tract, are presented in detail.

APPLICATION OF GRAFTSKIN TO ACCELERATE HEALING OF ULCERS IN DIABETIC FOOT SYNDROME.

Diabetic foot syndrome (DFS) is one of the severe and more frequent complications of diabetes. It is characterized by occurrence of chronic purulent necrotic processes (trophic ulcers) on the foot with damage of skin, soft tissues and osteoarticular system due to pathological changes in the peripheral nervous system (diabetic neuropathy) and vascular system (diabetic angiopathy). This study aimed to evaluate the possibility of accelerating of wound healing in DFS by using the dermal equivalent (graftskin) and determine the safety of the method, factors and indications for its application. The research included 60 patients with DFS who were cured at the period from 2013 to 2016 in departments of purulent surgery of Hospital of war veterans and Municipal hospital № 14 of Saint-Petersburg. The patients were divided into 2 groups by random sampling of two comparable groups in age and sex. The patients of main group were treated by standard method and using application of dermal equivalent (DE) on the area of trophic ulcers. The patients of control group had only standard treatment. The DE showed a high efficacy in the main group of patients. The application of DE in complex treatment of patients with DFS stimulated processes of healing and accelerated the rate of epithelization. The application of DE was the most effective in patients with neuropathic form of DFS.

Neuroprotective effects of erythropoietin in focal brain ischemia in rats.

Neuroprotective effect of erythropoietin administered before ischemia has been previously demonstrated. The efficiency of erythropoietin administration after ischemia was not studied, though in case of success these protocols would be applied in clinical neurology. In our experiments on the model of transitory focal ischemia, erythropoietin was injected intraperitoneally during the early and delayed postischemic period (3 and 12 h). The size of the necrotic zone, neurological deficit, and the severity of brain edema were evaluated in 48 h. Injection of erythropoietin in 3 and 12 h after ischemia significantly reduced the size of necrosis (p = 0.0007 and p=0.0016, respectively), neurological deficit (p=0.0013 and p=0.0062, respectively), and brain edema (p=0.02 and p=0.0186, respectively). Injection of erythropoietin after transitory focal cerebral ischemia produced a pronounced neuroprotective effect.

[Highly selective sodium-glucose co-transporter type 2 inhibitor empagliflozin as means of brain protection in conditions of chronic brain dyscirculation].

BACKGROUND: Chronic brain dyscirculation is one of the frequent type 2 diabetes mellitus (DM) complications and leads to patients' disability. Sodium-glucose co-transporter type 2 inhibitors (SGLT-2i) have been proven to have advantages for cardiovascular system, but their effect on the central nervous system (CNS) has not been studied enough. AIM: To study empagliflozin effect on CNS damage functional and laboratory parameters in patients with type 2 DM and, under experimental conditions, to investigate the mechanisms of the drug neurotropic effect. MATERIALS AND METHODS: The clinical part of the study included patients with type 2 DM on metformin monotherapy (n=39). Patients with a target glycated hemoglobin level formed the "MET" group (n=19), in patients with a non-target glycated hemoglobin level empagliflozin was co-administered for the following 6 months (the "MET+EMPA" group, n=20). Healthy volunteers comprised the control group (n=16). The cognitive status and neuron-specific enolase (NSE) and neurofilament light chains (NLC) concentration were studied. DM was modeled in rats, thereafter the rats were treated with empagliflozin for 8 weeks. Microglia activation was assessed using anti-Iba-1 antibodies and morphological changes in neurons when stained by the Nissl method. RESULTS: Both in the "MET+EMPA" and the "MET" groups cognitive deficits were observed, according to the Montreal Cognitive Assessment (MOCA) (24.0 (23.0; 27.0) and 25.0 (21.0; 27.0) points) and the Mini-Mental State Examination (MMSE) (23.75 (23.0; 27.0) and 25.0 (21.0; 27.0) points). Empagliflozin therapy led to the cognitive status normalization after 6 months (26.5 (24.0; 27.0) points according to the MOCA scale and 27.5 (24.0; 28.0) points according to the MMSE). Initially, all patients had a significant increase of NSE (3.60 (2.66; 3.76) ng/ml in the "MET" group, 3.22 (2.94; 3.54) ng/ml in the "MET+EMPA¼ group, 2.72 (2.13; 2.72) ng/ml in the «Control¼ group) and NLC (4.50 (3.31; 5.56) ng/ml in the «MET¼ group, 5, 25 (3.75; 6.25) ng/ml in the «MET+EMPA¼ group comparing with 3.50 (2.25; 3.50) ng/ml in the «Control¼ group). Empagliflozin therapy led to a significant decrease in NLC already after 3 months (3.80 (3.25; 3.87) ng/ml), without significant influence on the NSE level. In the experiment, DM was characterized by an increased number of activated microgliocytes and destructured neurons and a decreased number of neurons with a normal structure. Empagliflozin therapy was accompanied by a decrease in the number of immunopositive microgliocytes in the CA1 zone of the hippocampus and an increase in the number of structured neurons. CONCLUSION: Type 2 diabetes mellitus is characterized by functional and biochemical changes in the central nervous system even under satisfactory glycemic control. Therapy with empagliflozin has a neuroprotective effect, manifested in an improvement in cognitive status and a decrease in NLC level. Empagliflozin reduces neuronal damage and abnormal microglial activation.

[Appearance of stellate smooth muscle cells in the rat brain after transitory focal ischemia].

One of the poorly studied problems of the pathogenesis of the brain ischemic damage is the early reorganization of blood vessels in the zone of the transitory ischemia. The aim of the present study was to investigate the structural organization and cytochemical characteristics of smooth muscle cells (SMC) in the wall of the intracerebral blood vessels in 16 Wistar rats during the early postischemic period (48 hrs after a 30 minute-long ischemia). Examination of the lesioned hemisphere revealed the stellate cells, demonstrating positive reaction to alpha-smooth muscle actin, which seem to be a special population of structurally modified SMC, uncharacteristic to the intact brain of control animals (n=5). The functional role of these cells remains to be elucidated.

[Nestin and Musashi1 as the markers of neural stem cells in rat telencephalon following transitory focal ischemia].

Nestin and Musashil (Msi-1) proteins are most often used for labeling of neural stem cells and progenitor cells in vivo, however it remains unclear if these markers really label the same cells. As a result of the study of structural characteristics and localization of nestin- and Msil-expressing cells it was found that these proteins were detected in non-identical cell populations in the brain of intact 15 rats. We failed to find cell groups demonstrating a coexpression of nestin and Msi-1. However, after ischemic lesion of the brain, which was caused in 38 rats by an endovascular occlusion of the left medial cerebral artery for 30 min with the following reperfusion for 48 hours, both markers were detected in cells of subventricular zone and in ependymocytes. These results indicate the changes in cytochemical patterns of the candidate stem cells.

[Structural organization of striatal microgliocytes following focal ischemia].

Microgliocytes are currently known as structurally labile cells, that, by changing the length of their processes, control the synaptic organization of the brain. The aim of this study was to investigate structural organization of microglia of the striatum and of the forebrain periventricular area in rat following transitory focal ischemia. In the absence of brain infarction, ischemic lesion was found to activate microglia, which contributed to rearrangement of striatal neuropil. As microgliocytes became activated, they changed their shape from characteristic dendritic one to oval and rounded, which are typical to amoeboid microglia. Microgliocytes were shown to be capable of proliferation.

Influence of the cumulative effect of zoledronic acid on periodontal microcirculation in rats.

PURPOSE: To evaluate the effect of repeated administration of zoledronic acid (ZA) on the development and severity of osteonecrosis of the jaws. METHODS: In the experiment, 36 rats were used, which were divided into 4 groups: group 1 was injected with saline for 6 weeks, group 2 was injected with ZA once, group 3 was injected zoledronic acid for 3 weeks once a week, group 4 was injected with ZA for 6 weeks once a week. While taking medications, the tooth was removed. The volumetric blood flow rate was studied using laser and high-frequency ultrasound Doppler in the area of the periodontium of an extracted tooth in rats with the application of acetylcholine. Bone tissue was examined out using CBCT. RESULTS: In group 2, there was a violation of blood flow in the mucous membrane, bone microcirculation, but no reliable data was obtained in the bone defect in comparison with group 1. In groups 3 and 4, there was significantly disrupted blood flow. This led to an increase of the osteonecrosis (maximum at the 4th group), which was confirmed by data obtained using CBCT. An inverse relationship was observed between the blood flow of bone tissue and the size of the defect after tooth extraction. CONCLUSION: The introduction of ZA in a dose-dependent fashion resulted in impaired endothelial vasodilation and impaired blood flow to extraction sockets. These findings might explain the development of osteonecrosis of the mandible following removal of a first molar.

[Effect of hepatoprotector remaxol infusion on liver function in obstructive jaundice model in rats].

Remaxol is a new infusion hepatoprotector that contains succinic acid, inosine, methionine and methylglucamine. The hepatoprotective effect of remaxol on the liver function has been studied on the model of obstructive jaundice in rats, on the terms of one and two weeks after ligation of the common bile duct (M. A. Aller, et al., 2004). Sixty rats were randomly divided into six groups: sham-operated rats with cholestasis, 0.9% NaCl treated rats with cholestasis, and remaxol treated rats with cholestasis, all on the one week (per os n=10) and two weeks (n=10) terms. Remaxol was injected into the tail vein in a dose of 1 ml/100 g during the first week after the induction of cholestasis. The rats were removed from the experiment after one and two weeks of postoperative period, respectively. The size and weight of the liver and the degree of ascites were measured, and the blood samples were taken to analyze for bilirubin, alkaline phosphatase, gamma-glutamyl transpeptidase, alanineaminotransferase, aspartataminotransferase. Morphological changes in the liver were also studied. The biochemical parameters of blood and morphological evolution of tissue of liver in both one and two weeks after the induction of cholestasis showed a significant hepatoprotective effect of remaxol.

Disorders of microcirculation in the mechanism of bisphosphonate osteonecrosis: preliminary study in rats.

We investigated the possibilities of angioprotection and the reduction of osteonecrosis in rats that had been given bisphosphonates. In our experiment, 27 rats were divided into three groups: Group 1 was injected with saline; Group 2 was given zoledronic acid for six weeks; and Group 3 was given zoledronic acid for six weeks, with added doses of sulodexide after three weeks. After that we constructed a model of how the teeth should be extracted. The velocity of linear blood flow in the periodontal area of an extracted tooth in rats was studied using laser and high-frequency Doppler ultrasound (with the application of the vasoactive substance acetylcholine 3% for 1min). We evaluated changes in the structure of the bony tissues of the head using computed tomography, comparing the control group with the saline group. A rapid reduction in microcirculation was detected during the use of zoledronic acid for six weeks. A smaller reduction in microcirculation was detected after three weeks of treatment with sulodexide and zoledronic acid. There was a reduction in blood flow in the mucous membranes and, to a greater extent, in bony tissue. Zoledronic acid causes significant impairment of the periosteal blood flow to the mucous membranes because of a complex of disorders, which includes both the cellular component (impaired endothelium-dependent vasodilation of the mucous membrane vessels) and by reducing the intensity of microcirculation in the mucous membranes and bony tissues. Sulodexide, however, improves the restoration of blood flow and reduces the severity of osteonecrosis.

Simulation of unilateral ischemic injury to the striatal neurons inflicted by short-term occlusion of the middle cerebral artery.

The reproducibility of brain injury was evaluated by simulating ischemia in rats by 30-min occlusion of the middle cerebral artery. The selected ischemia-reperfusion protocol was characterized by high reproduction of the striatal neuron injury, which fact suggests this model for studies of nerve tissue reactions to injury and for evaluation of the efficiency of neuroprotective drugs.

[Selective death of the striatum neurons in rats after the transient occlusion of the middle cerebral artery].

The aim of the present investigation was to determine the neuronal population of rat telencephalon that was most sensitive to ischemic damage under the experimental condition of transient focal cerebral ischemia. It was found that 30-minute ischemia of the left hemisphere resulted in a significant decrease of neuronal population in the dorsomedial part of caudatoputamen. Local neural cell death was accompanied by a moderate activation of the astrocytes.

[Effects of individual and combined administration of ethylmethylhydroxypyridine succinate and ischemic preconditioning on ischemic-reperfusive myocardial injury in rats].

It was shown previously that ethylmethylhydroxypyridine succinate (EMHPS) can produce metabolic cardioprotective action due to its antihypoxant and antioxidant properties. In the present study, the cardioprotective effects of EMHPS administered in doses 50 and 100 mg/kg alone and in combination with ischemic preconditioning have been studied on the model of ischemic-reperfusive myocardial infarction in rats. It is established that both the administration of EMHPS in a dose 50 mg/kg and the ischemic preconditioning produce significant limitation of the infarction size. A combined use of EMHPS in a dose of 50 mg/kg and ischemic preconditioning also provided significant protection, although the effect was not further potentiated. In contrast, EMHPS administered in a dose 100 mg/kg did not ensure reliable protection against infarction, while a combination of this drug dose with the ischemic preconditioning even partially eliminated the infarction-limiting effect of the latter.

Induction of nestin synthesis in rat brain cells by ischemic damage.

Nestin, an intermediate filament protein, is known to be expressed in proliferating and provisional cells in the forming mammalian brain, disappearing on differentiation. The aim of the present work was to identify the morphological types and locations of cells regaining the ability to synthesize nestin after transient total brain ischemia in rats. Transient ischemia was found to be followed by the induction of nestin synthesis in astrocytes in the damaged area; these cells acquired structural features not characteristic of the adult brain, and these persisted in the long term. Nestin synthesis was also induced in proliferation-capable undifferentiated cells in the subventricular zone. The acquisition by astrocytes of some of the phenotypic features of immature glial cells, however, does not provide grounds for the notion that they were transformed into neural stem cells.

[Ultrasound-induced myocardial preconditioning: analysis of its effectiveness and mechanisms].

It has been shown that exposure of the isolated rat heart perfused according to Langendorff to therapeutic ultrasound (210 kHz and 0.5-1.5 W/cm2 ) induces a cardioprotective response similar to ischemic preconditioning. This reduces the infarct size and improves the postischemic systolic and diastolic function. The ATP-sensitive K+ channel blocker glybenclamide abolished the protection afforded by ultrasound; in contrast, the free radical scavenger N-2-MPG did not influence the ultrasound-induced cardioprotective response.

[Ischemic damage-induced nestin synthesis in the rat brain cells].

Nestin, an intermediate filament protein, is known to be expressed in the proliferating and provisional cells of the developing mammalian brain and is lost during differentiation. The aim of the present study was to determine the morphological type and localization areas of the rat brain cells exhibiting the ability to synthesize nestin after a short-term global ischemia of the brain. Induction of nestin synthesis after a short-term ischemia was found within the injured brain areas in astrocytes, which exhibited structural features atypical for these cells in mature brain and maintained them for a long time, and in the morphologically undifferentiated cells of subventricular zone, which were able to proliferate. However, acquisition by astrocytes of some phenotypic properties of immature glial cell does not by itself support the view that they may transform into neural stem cells.

[Preclinical studies of drugs on animal stroke models]. / Doklinicheskie issledovaniia lekarstvennykh sredstv na biologicheskikh modeliakh insul'ta.

Preclinical studies are studies using experimental models of stroke in animals as well as on neurons, cell neuronal cultures and surviving brain slices. They directed both towards testing the efficacy and evaluation of the mechanisms of action of drugs, and the study of the mechanisms of ischemic damage to search for new targets for stroke treatment. This article shows the basic principles of the organization and planning of animal models of ischemic stroke. Modeling of cerebral ischemia on the different models and animal species, the modern principles of assessment of brain damage are considered as well.

[The administration of neurocytoprotectors in a rat model of experimental spinal cord ischemia]. / Primenenie neirotsitoprotektorov v usloviiakh éksperimental'noi ishemii spinnogo mozga u krys.

AIM: To study an effect of cortexin on functional recovery and morphology of the spinal cord of rats with spinal cord ischemia. MATERIAL AND METHODS: Spinal cord ischemia was achieved by ligation of the infrarenal abdominal aorta in 16 rats stratified into two equal groups: the ligation of infrarenal aorta was performed in the control group, aorta ligation was performed also in the experimental group with preliminary intraperitoneally administration of cortexin in a dose of 0.15 mg/kg 30 min before procedure. Evaluation of neurologic deficit was performed by the Tarlov's scale. Morphological evaluation was made by analyzing the histological sections of the lumbar and sacral cord using the Nissl's method of coloring. Statistical analysis was performed as well. RESULTS AND CONCLUSION: A pronounced and significant effect of cortexin, which was clinically expressed in a decrease in neurological deficit (p=0.0095), morphologically in an increase in the number of normochromic neurons (р=0.01), and a decrease in shrunken neurons (р=0.0001) and shadow cells (р=0.0003), was noted. The results suggest a potential myeloprotective effect of cortexin. The drug can be considered in the context of treatment of vascular myelopathy.

Experimental model of osteonecrosis of the jaw in rats treated with zoledronic acid.

We have examined the development of medication-related osteonecrosis of the jaws (MRONJ) in rats with no previous accumulation of zoledronic acid in the mandible. Ten male Wistar rats (weight 350-400g) were anaesthetised with chloral hydrate 450mg/kg intraperitoneally and the first and second mandibular molars on the left side were extracted. The five experimental rats were given six injections of zoledronic acid 0.18mg/kg over the next four weeks (total dose 1.08mg/kg). Two injections were given at once as an intravenous bolus injection (0.36mg/kg). Then rats were given 4 injections (0.18mg/kg) with 1 week interval over the next four weeks, after which they observed for a further four weeks. The five control rats were injected with saline. At the end of the eighth week, the animals were killed by asphyxiation in a carbon dioxide chamber, and their bone structure was visualised using cone-beam computed tomography (CT) and Galaxis software. We then studied the mandibles histopathologically to investigate the incidence of necrosis and infiltration of inflammatory cells. The cone-beam CT images in the experimental group showed deficiencies in the bone structure in the extracted molar area of the lower alveolar ridge. The histological findings in the mandibles of the group given zoledronic acid showed necrosis and infiltration of inflammatory cells, which were not present in the control group. We conclude that the immediate effect of zoledronic acid on the bone tissue during regeneration is an important factor in the development of MRONJ, in addition to the previously reported effects of the duration of treatment with zoledronic acid.

[The role of oxygen free radicals in the mechanisms of local and distant ischemic myocardial preconditioning].

The phenomenon of ischemic preconditioning consists in increase in myocardial tolerance to ischemia after short periods of ischemia and reperfusion of the myocardium (local preconditioning) or a distant organ (distant preconditioning). This study is dedicated to the role of oxygen free radicals (OFR) in the mechanisms of preconditioning; pharmacological inhibition of OFR with N-2-mercaptopropionylglycin, a synthetic anti-oxidant, was used. Mouse experiments demonstrated a reduction in the infarction-limiting effect of local preconditioning as a result of OFR inhibiting. This confirms the hypothesis according to which OFR play an important role in the mechanisms of launching and mediating the protective effect of local preconditioning. On the contrary, application of the same dose of N2-mercaptopropionylglycin does not lead to a significant weakening of the infarction-limiting effect of distant preconditioning caused by 20 min of ischemia and 15 min of reperfusion of the small intestine. Thus, it is unlikely that OFR participate in the realization of the effect of distant preconditioning caused by small intestinal ischemia. The authors discuss hypothetic molecular mechanisms of distant myocardial preconditioning.