[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.

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.

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.

[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.

[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.

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.

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.

[Preconditioning by physical factors: role of active forms of oxygen].

In the review mechanisms of protective action of a hyperthermia, light and low-intensity ultrasonic radiation are considered. These physical factors don't cause oxygen starvation, however promote the increase of organ's tolerance to an ischemia/hypoxia. On materials of original articles the analysis of preconditioning mechanisms cause by high temperatures, low-intensive ultrasonic and laser irradiation was carried out at ischemia. By comparison of processes in tissues at influence by physical factors the general triggers--active forms of oxygen (O2*, H2O2, HO*) were revealed.

[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.

[Creatine in a metabolism of cell and its protective action at brain ischemia].

The aim of this review was the discussion of creatine involvement in metabolism of nervous tissue cells. The questions of creatine penetration through the blood brain barrier and creatine transporter expression were raised. Also mechanisms of creatine protective effect were considered at experimental models of brain ischemia. It was shown that creatine was involved in energy metabolism (creatine phosphate synthesis), inhibition of excitotoxicity. Besides it had antioxidant and antiproliferative effects. The creatine delivery problem was also discussed. Synthesis of substances capable to get through the blood brain barrier without CRT was the possible solution of the problem. The most perspective substances were creatine amides apparently capable to move through cell membranes without amino acid transporters. Prospects of their application were discussed.

[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.

[Mechanisms of cerebral protection from ischemia by tea constituents].

Epidemiological and clinical studies in recent years have shown that regular consumption of green or black tea significantly reduces the risk of cardiovascular diseases, including ischemic stroke. This review presents the clinical and experimental studies of the antiatherogenic, antiplatelet, antioxidant, antiinflammatory and other mechanisms of action of tea and substances in its composition. Effects of tea and its components, are described after long-term, and a short-term consumption. The role of catechins and specific amino acid L-theanine in the possible mechanisms of protection against cerebrovascular disease are discussed.

[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.

[Determination of circulation disturbance in the rat lungs in modelling of chronic obstructive disease].

Development of chronic obstructive pulmonary disease (COPD) involves not only the bronchial and respiratory areas of the lungs, but also the system of pulmonary circulation, which begins with the defeat of capillary blood flow. One of radiological methods of studying lung microcirculatory functions is perfusion scintigraphy. We designed the technique of radiological examination and identified its abilities in determination of the role of vascular dysfunctions in experimental model of development of COPD. We assessed the results of pharmacological agents that affect the microcirculatory bed of the lungs and smooth muscles of pulmonary arteries in rats. Studies have shown the promise of the possibility of using the drug sulodexide for studying impaired endothelial function in clinical practice.

[Cytoprotective effect of creamide drug in the experimental model of the brain ischemia/reperfusion in rats].

The influence of creatine or its derivates on the cell energy potential may be one of the possibl approaches to induce neuroprotection. Effect of creamide (creatinylglycine ethylic ether fumarate) on the brain injury was studied in the experimental model of the brain ischemia/reperfusion in rats. The experiments were carried out in 14-20 weeks old male Wistar rats weighing 240-300 g, anesthetized by chloral hydrate (430 mg/kg). Creamide was administered intravenously at the doses of 50, 70, 140, and 280 mg/kg. For comparison phosphocreatine was used at the dose of 255 mg/kg. Creamide and phosphocreatine were administered intravenously (in volume of 1 ml within 5 min) 30 min before cerebral middle artery occlusion. Focal cerebral ischemia for 30 min was produced by endovascular suture occlusion with the subsequent 48 h reperfusion period. Creamide administration resulted in dose-dependent decrease of brain ischemic injury. Creamide administered at the doses of 140 and 280 mg/kg was more effective as compared with phosphocreatine (255 mg/kg). The data obtained open new perspectives for further research and development of new creatine-derived drugs with neuroprotective action.

[Effect of intragastric creatine glycine ethylic ether fumarate administration in a rat model of occlusive ischemia].

The aim of the study was to investigate neuroprotective effect of creatine glycine ethylic ether fumarate (creamide). The methods involved intragastric administration of creamide in doses of 30 and 50 mg/kg twice a day for 10 days. Focal 30 minutes cerebral ischemia model by endovascular suture occlusion of the middle cerebral artery in a rat with subsequent reperfusion period for 48 hours was produced. Assessment of creamide stability in gastric juice was performed. Ischemic lesion volume accompanying focal ischemia was visualized and determined. Similar infarction patterns had been found with histological methods. Garcia scale was used for clinical study of neurological deficit in rats. Our data suggest a significant neuroprotective effect of creamide in dosage 50 mg/kg administered twice a day which decreased brain lesion volume produced by ischemic and reperfusion injury.

[Amides of creatine: perspectives of neuroprotection].

We evaluated the efficacy of derivatives of creatine and amino acids (CrAA) for decreasing cerebral injury in rats with transient middle cerebral artery occlusion (MCAO). Neuroprotective effects of amides of creatine and glycine (CrGlyOEt), phenylalanine (CrPheNH2), thyrosine (CrTyrNH2), and GABA (CrGABAOEt) were investigated. Brain injury was evaluated on day 2 after transient MCAO using a TTC staining of brain slices. Compared with the MCAO control group, all the CrAms showed decreased cerebral injury (p < 0.05). However CrPheNH2, CrTyrNH2, and CrGABAOEt were toxic after intravenous administration and investigated only after intraperitoneal injection. CrGlyOEt did not show any toxicity at dose of 1 mmol/kg. These data evidenced that creatinyl amides can represent promising candidates for the development of new drugs useful in brain ischemia treatment.

[Early ischemic preconditioning against focal transient and permanent brain ischemia in rats: role of collateral circulation].

We hypothesize that early ischemic preconditioning (IPC) can afford protection against focal brief and prolonged cerebral ischemia with subsequent reperfusion as well as permanent brain ischemia in rats by amelioration of regional cerebral blood flow. Adult male Wistar rats (n=97) were subjected to transient (30 and 60 minutes) and permanent middle cerebral artery (MCA) occlusion. IPC protocol consisted of two episodes of 5-min common carotid artery occlusion + 5-min reperfusion prior to test ischemia either followed by 48 hours of reperfusion or not. Triphenyltetrazolium chloride and Evans blue were used for delineation of infarct size and anatomical area at risk (comprises ischemic penumbra and ischemic core), respectively. Blood flow in the MCA vascular bed was measured with use of Doppler ultrasound. The IPC resulted in significant infarct size limitation in both transient and permanent MCA occlusion. Importantly, IPC caused significant reduction of area at risk after 30 min of focal ischemia as compared to controls [med(min-max) 11.4% (3.59-2 0.35%) vs. 2.47% (0.8-9.31%), p = 0.018] but it failed to influence area at risk after 5 min of ischemia [med(min-max) 7.61% (6.32-10.87%) vs. 8.2% (4.87-9.65%), p > 0.05]. No differences in blood flow were found between IPC and control groups using Doppler ultrasound. This is suggestive of the fact that IPC does not really influence blood flow in the large cerebral arteries such as MCA but it might have some effect on smaller arteries. It seems that, along with well established cytoprotective effects of IPC, IPC-mediated reduction of area at risk by means of improvement in local cerebral blood flow may contribute to infarct size limitation after focal transient and permanent brain ischemia in rats.