Morphological characteristics of dysplasia in the mucous membrane adjacent to the tumor in intestinal type gastric cancer

Introduction. Despite a significant number of publications and a concept known as Correa’s cascade, dysplas-tic processes and the mechanisms of gastric carcinogenesis, are still far from being completely understood. Dysplasia and the processes in the mucous membrane adjacent to the tumor node, their significance, and their role in the field cancerization have also been studied insufficiently. The aim of this work was to analyze the frequency of occurrence and some characteristics of high- and low-grade dysplasia in the gastric mucosa at variable distances from the tumor node. Materials and methods. We carried out a prospective histological study of surgical specimens from 49 patients with intestinal type gastric adenocarcinoma. We studied tissues from the tumor node and adjacent gastric mucosa at various distances from the tumor and assessed the frequency of occurrence and some characteristics of low- and high-grade dysplasia. Results. In the mucous membrane adjacent to the intestinal type adenocarcinoma, 73.5% of cases demon-strated low- and high-grade dysplasia. In all cases, background and precancerous processes were found in areas adjacent to the tumor node with low- and high-grade dysplasia. Conclusion. The incidence of low- and high-grade dysplasia detected in the mucous membrane adjacent to intestinal type gastric adenocarcinoma significantly decreases as the distance from the tumor node in-creases. Dysplastic changes are associated with epithelial hyperplasia, intestinal metaplasia, and inflamma-tory and atrophic changes. The results obtained support field cancerization and highlight the need to study morphological, molecular, and genetic alterations in the gastric mucosa adjacent to the tumor more deeply. The dysplastic changes present at the resection line area indicate that this fact must be considered when determining the resection line. Keywords: gastric cancer, low-grade dysplasia, high-grade dysplasia, epithelial dysplasia, intestinal meta-plasia, inflammatory infiltration, atrophy

Correlation of microvasculature structure with metastatic potential of localized forms of colorectal cancer

Introduction. Non-metastatic colorectal cancer can recur within five years as distant metastases in about 25% of stage II patients and 50–60% of stage III patients. It is crucial to identify the subgroup of patients with the highest risk of recurrence. Our study aimed to determine the effect of microvascular density (MVD) and pericyte impaired microvessels (PIM) on the risk of metastasis of colorectal adenocarcinomas. Materials and methods. We carried out a retrospective study of the surgical material for colorectal cancer without metastases in regional lymph nodes. The cohorts included cases with synchronous distant metasta-ses (n=53), metachronous metastases (n=45), and without distant metastases (n=53). In the last group, the follow-up period was from 64 up to 92 months. We performed triple immunohistochemical staining: ERG, α-SMA, and Podoplanin. At low magnification, we determined the areas of highest microvessel density, calculated them on an area of 1.0 mm2 with a magnification of x400. The number of microvessels without α-SMA expression was counted, and eventually the microvessel immaturity index Index-V = PIM / MVD was calculated. Results. Normal blood vessels were characterized by the expression of ERG in endothelial cells and α-SMA in pericytes, while at immature tumor microvessels, the latter were absent. The difference in MVD in the groups was statistically insignificant (p=0.414), on average 10/mm2 for non-metastatic tumors and 11/mm2 for metastatic ones. Metastatic tumors showed significantly higher PIM (mean 8/mm2 vs. 2/mm2) and Index-V (mean 0.69 vs. 0.21). Both showed a significant correlation with distant metastases (p <0.001). Conclusion. The data obtained demonstrate that imperfect tumor neovascularization correlates with metasta-sis, which leads to a worse prognosis. The density of microvessels and their structural features are important independent prognostic factors for patients with colorectal cancer. Evaluation of angiogenesis in a tumor in terms of the number and maturity of newly formed vessels enable to elucidate malignant potential of the tumor. Keywords: angiogenesis, pericytes, microvessel density, colorectal cancer, prognosis

Epithelial-mesenchymal transition in main types of gastric carcinoma

Introduction. The rapid development of basic science enabled us to significantly expand our understanding of various intercellular interactions. Epithelial-mesenchymal transition (EMT) is known to play a key role in certain tissue formation in the embryonic period. However, recent data show that EMT can also be observed in some pathological conditions, in particular, in various neoplasm development. This suggests that there are a number of alternative and fundamentally new mechanisms for the tumor formation and progression. Thus, EMT, which occurs in carcinomas, increases the invasiveness, immunoresistance, immunity to therapy, and the metastatic potential. Knowledge of EMT features and their timely recognition in morphological tumor diagnosis is of great predictive importance for patients. The aim of the research was to study the morphologi-cal features of epithelial-mesenchymal transition in the main types of gastric cancer. Materials and methods. We studied specimens of gastric carcinomas (N=64) including 31 cases of diffuse type, 19 cases of intestinal type, and 14 cases of mixed type. Results. All cases of the diffuse carcinoma group showed spread EMT features, which appeared already in the mucosa and completed with positive vimentin expression in 93.5% of cases. The malignant cell prolifera-tive activity was low; however, in 29% of cases we detected areas of moderate or even high activity. In the intestinal type gastric cancer, EMT developed as a result of tumor progression, it arose more often in the deeper layers and was incomplete and focal. As a rule, the proliferative activity of tumor cells was high and moderate. Vascular invasion occurred more often in diffuse type (90.3%), less often in mixed type (71.4%), and even less often in the intestine type (55.8%) gastric carcinoma. Conclusion. The variety of morphological features of EMT, its frequency, prevalence, completeness, and sequence in the development of various types of gastric cancer determines the features of their clinical manifestation and influences their further management. Keywords: gastric cancer, diagnosis, histological main types, EMT, morphopathology

The role of seminal plasma extracellular vesicles in changes in the morphofunctional characteristics of human spermatozoa

For a long time, the role of seminal plasma during human fertilization remained underestimated. Numerous studies related to the development of different methods for human embryo in vitro cultivation were gener-ally concerned with the quality of male and female gametes. However, in recent years, the development of Omix technologies provided a new insight into great seminal plasma influence on the morphofunctional characteristics of spermatozoa. This is especially true for the regulatory function of extracellular vesicles secreted by male reproductive tract cells. In this work, we attempted to analyze current data on the influence of extracellular seminal plasma vesicles on the morphofunctional characteristics of spermatozoa to solve male infertility topical issues. The review includes studies by foreign and Russian research groups that werу conducted within the past 5 years and found in PubMed, Google Scholar, and Cochrane Library databases. Very few studies demonstrate that seminal plasma vesicles act as functional regulators of male fertility and their dysfunction may lead to infertility. The use of seminal plasma extracellular vesicles in clinical practice may significantly increase the success of IVF programs, especially in impaired spermatogenesis. Keywords: extracellular vesicles, exosomes, biomarkers, seminal plasma, spermatozoa, assisted reproductive technology, cell biology, morphology

Experimental model of chronic focal osteomyelitis for in vivo studies

Introduction. The article describes an experimental model of chronic suppurative osteomyelitis in a rabbit. As new therapeutic and diagnostic algorithms for the supervision of patients with osteomyelitis appear, there is an growing need to compare the methods of surgical debridement and plasty of bone defects in an infectious process, in order to create experimental standardized pathological conditions as close to the clinical course of the disease in humans as possible. The aim of the study was to develop an experimental model of a standardized chronic purulent bone cavity, suitable for a comprehensive assessment of surgical debridement effectiveness and osteoplastic properties of bone substitute materials. Materials and methods. A standardized defect of the tibia in 24 rabbits was formed. The Staphylococcusaureus strain was used as an infectious agent. A dynamic assessment of the main indicators of blood counts in animals was carried out. The formation of chronic osteomyelitis was evaluated using radiography, com-puted tomography methods and histological studies. Results. It was shown that purulent bone wound developed in experimental animals with the technique cre-ated, and a defect with signs of a chronic purulent-inflammatory process was demonstrated. Conclusion. The proposed model of chronic osteomyelitis is reproducible. Operational flexibility and identi-cal in size and location bone defects allow to use this model in new osteoplastic material research. Keywords: chronic osteomyelitis, experiment, experimental animals

Structural dermis remodeling in a skin expansion rat model

Introduction. Skin expansion is known to be the most effective way to obtain skin for alloplastic closing of large defects, and it has proven to be successfully used in various fields of surgery, cosmetology, and traumatology. At the same time, the issues of skin flap restructuring when it is stretched and possible range of its application are still relevant. In this regard, the aim was to study the adaptive skin rearrangements of the fibrous skeleton in a murine skin expansion model. Materials and methods. We used the skin of mature male Wistar rats (N=30) after a 2-week stretching. We utilized a complex morphological light and electron microscopy approach as well as an immunohistochemi-cal method to determine the types of collagen and to study the alterations in skin samples. Results. We revealed pronounced reactive changes in the skin structural components in the skin expansion area. On day 14, we observed a decrease in the epidermal cell layer thickness as well as stretching, partial disorganization, and damage of dermal fibrous structure. At the same time, cellular mechanisms of regen-eration and activation of collagen synthesis were launched, the morphological substrate of which was (1) a significant 2.7-fold increase in the number density of fibroblasts, which produce substances for building fibrous structures, (2) a five-fold increase in macrophages, which are a catalyst for the fibroblast functional activity and (3) a collagen fiber types’ redistribution s with Type III collagen structures’ predominance. Conclusion. The results indicate, first of all, the restructuring of the dermal fibrous component, which im-plies reparative and restorative processes. These must be taken into account in clinical practice to achieve not only an esthetic effect but also the subsequent adequate functioning and vital activity of the skin flap. Keywords: skin expansion, fibrous dermis, remodeling, skin, hyperextension

Expression of cancer stem cell markers CD44, CD133, and ALDH in a primary tumor before and after platinum-containing chemotherapy in ovarian cancer

Introduction. Ovarian cancer (OC) is characterized by an unfavorable clinical course. Difficulties in the treatment of OC can be due to intratumoral heterogeneity, which includes the presence of stem cells. The aim of this study was to assess the expression of stem markers in the tissue of primary OC before and during chemotherapy of OC in association with the clinical features of the disease. Materials and methods. A retrospective study evaluated tissue samples of the primary tumors of patients (n=28) with stages I–IV epithelial OC obtained before or after 3 courses of chemotherapy. The expression of ALDH, CD44, and CD133 was assessed by immunohistochemistry. Results. In samples of high-grade serous adenocarcinoma, the percentages of cells expressing ALDH (p=0.008), CD44 (p=0.026), and CD133 (p=0.059) were lower than in other subtypes. Tissue samples obtained before treatment showed a higher percentage of cells expressing CD44 (p=0.053) than the ones obtained after neoadjuvant chemotherapy. There was a tendency towards higher expression of CD44 (p=0.056) and ALDH (p=0.074) in stages I–II tumors when compared to that in stages III–IV. In the neoadjuvant chemotherapy group, patients with clinically platinum-sensitive tumors had a higher percentage of CD44+ cells than those with non-platinum-sensitive ones (p=0.038). The number of tumor cells expressing ALDH rose with the increase in CD44+ cells number (R2=0.280, p=0.005). We found a positive correlation between the numbers of CD44+ and CD133+ cells in the tumor parenchyma (r=0.408, p=0.031). Conclusion. Cancer stem cell markers are co-expressed in primary tumor tissue in OC. The expression of stem markers differs depending on the histological subtype and the presence of prior exposure to chemotherapy. Keywords: tumor stem cells, ovarian cancer, chemotherapy, CD44, CD133, ALDH, immunohistochemistry

Effects of L-alpha-aminoadipic acid on neurons and glia of the rat brain striatum

Introduction. Few published studies have examined the role of glia-neuron interactions in neurodegen-eration. In this regard, the search for new experimental models is important. L-alpha-aminoadipic acid (L-AA), being a structural analogue of glutamate with a selective toxic effect on astroglia, is of particular interest. However, morphological and neurochemical changes caused by L-AA still remain unclear. The aim of the study was to characterize immunomorphological changes of glia and neurons in the striata of rats after L-AA administration. Materials and methods. On days 3 and 12 after L-AA stereotaxic administration, we studied astrocytic pro-teins localization using immunofluorescence methods: GFAP, vimentin, glutamine synthetase, along with oligodendroglia (by cyclonucleotidphosphatase expression), microglia (IBA1 Ca-binding protein), neuronal nuclear protein NeuN, and the astroglia proliferative activity (based on Ki67 localization). Results. We detected astrocyte death and a decrease in glutamine synthetase immunoreactivity in the le-sioned area, but no changes in the microglia reaction and the L-AA effect on neurons and oligodendroglia. The astrocyte loss was replenished by proliferation and migration of newly formed immature astrocytes, and a glial scar formed on day 12 after the surgery. Conclusion. L-AA administration, which causes the death of striatum astrocytes in the injection area, can serve as a convenient model for studying reactive changes in astroglia and astrocytic dysfunction while revealing the pathogenetic patterns of neurodegenerative processes. Keywords: astrocytes, striatum, L-alpha-aminoadipic acid, gliosis, glial toxin

The role of adipose tissue in the healing of rat uterine wall after a full-thickness surgical incision

Introduction. Data about the role of components of adipose tissue in the repair of damaged uterine walls are limited, although a number of authors claim that cell-based drugs from adipose tissue have a positive effect on the repair of damaged uterine walls in laboratory rodents. Meanwhile, stem cells derived from adipose tissue are considered to be the most promising type of cells in regenerative medicine. The aim of the studywas to evaluate the adipocyte components in the uterine wall of rats in healing after a full-thickness surgi-cal incision. Materials and methods. We conducted the study on 40 female Sprague Dawley rats. The animals were sub-jected to a full-thickness longitudinal incision in the wall of the right uterine horn, with the left one serving as an intact control. We carried out morphological examinations of the uterine walls daily in 5 animals from day 1 to 7 and on day 15. The sections from paraffin blocks were stained with hematoxylin and eosin and Mallory’s trichrome staining. Immunohistochemistry detected FABP4+ adipocytes and CD68+ macrophages. The morphometric study was carried out using the Leica system (Leica, Germany). The results underwent processing in the Statistica 12 software (StatSoft). Results. We noticed the period of the most active interaction of adipose tissue with the damaged horn to last from day 3 to 15 and coincide with the macrophage activation in the healing zone. The intact left uterine horn was not involved in the interaction processes with the mesenteric adipose tissue. Starting from day 3 FABP4+ cells in the uterine wall of the operated horn formed groups, creating rounded nest-like structures. Clusters of FABP4+ cells were localized in the healing zone, near the suture material, and in the perime-trium near the mesentery attachment sites. The changes over time of the indicators of the area of cell nests depended on the localization and duration of healing. There were no FABP4+ cells in the left intact horn. Conclusion. We characterized the morphological interaction of adipose tissue with the damaged uterine wall during the first two weeks after a full-thickness surgical incision of the rat uterine horn. The results of the study indicate that adipocytes take an active part in the healing after a surgical incision of the rat uterine wall at the earliest stages. Keywords: rat uterus, hysterotomy, healing, adipocytes, macrophages

Organ and tissue damage related to SARS-CoV-2: the biological model for experimental (preclinical) trials on golden hamsters Mesocricetus auratus

Introduction. Amid the pandemic of the new coronavirus infection COVID-19, experimental models for screening both newly developed vaccines and drugs, and the already registered active pharmaceutical in-gredients tested for new indications are in high demand. The registration of changes in biometric and mor-phological parameters that are significant for the investigative pathology can be an optimal screening tool for antiviral drugs and vaccines to treat COVID-19. In this regard, the purpose of this study was to describe the changes over time of organ and tissue changes using a biological model of a SARS-CoV-2-associated infection in the golden hamsters Mesocricetus auratus. Materials and methods. We performed the study in golden hamsters Mesocricetus auratus weighing 80–100 g. The animals were infected through intranasal administration of a culture of SARS-CoV-2 virus containing 4 × 104 TCID50/mL. We recorded the animals’ weight before the infection and during the next 14 days and measured the specific gravity of the internal organs and the degree of their moisture saturation on days 3, 7, and 14 after the infection. Additionally, tissue samples were fixed in 10% neutral formalin; the preparation of histological specimens was performed according to the standard procedure. Statistical data processing was carried out using non-parametric tests. Results. In the model of SARS-CoV-2 infection in Mesocricetus auratus, we observed the manifestation of the infectious disease after 3 days. The most pronounced pathological changes in the overall health status of the animals and in the histology of internal organs were seen 7 days after the infection. We determined the weight loss and significant deviations in gravimetric coefficients of lungs, heart, spleen, and kidneys to be the indicators revealing the infectious disease course changes over time. Histologic evaluation showed typical changes in the SARS-CoV-2-associated visceral damage: the formation of polymorphonuclear cell infiltrates in the lung interalveolar septa and patchy dystrophic changes in the neurocytes of the brain screen-type centers with the demyelination of the commissural nerve guides. The detected pathological manifestations corresponded in time to an increase in the virus replicative activity in the lungs. Conclusion. The experimental model of the SARS-CoV-2-associated infection in golden hamsters Mesocricetus auratus can be recommended for screening experimental (preclinical) studies of the promising drugs’ efficacy for pathogenetic and etiotropic therapy of COVID-19. Keywords: SARS-CoV-2, golden hamsters, morphometry, organ and tissue structural damage