Search

The subcutaneous tissue of rats after implantation of polypropylene materials with adsorbed bone marrow-derived mesenchymal multipotent stromal cells (MMSCs) was studied using light microscopy. Inflammation in response to implantation was mild, and the foreign material was encapsulated into a thin strip of dense fibrous connective tissue with multinucleated macrophages. By 1 year after introduction of the monofilament and 6 and 12 months after implantation of the mesh product, some threads were deformed, broken, and had sharp edges. Small fragments of foreign material appeared in the adjacent tissues surrounded by their own relatively thick acellular capsule. As a result of preliminary adsorption of MMSCs on polypropylene, the thickness of the connective tissue capsule decreased, its vascularization increased, and the severity of inflammatory infiltration decreased. However, all effects of MMSCs adsorption in rats were transient and disappeared within 1 week., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

In a patient after implantation of a metal screw implant into the bone with suturing of the soft tissues above it after 6 months there was a spontaneous delimitation of the product by a thin strip of compact bone tissue, most likely formed from the bone structures damaged during the operation. Small bone fragments formed during the preparation of the implantation bed were found in the tissues as homogeneous eosinophilic deposits without inflammation and macrophage reactions.

A literature search was conducted to review papers on the results of studies of clear cell renal cancer (CCRC) vascularization. Numerous data on the relationship between tumor pathogenesis and its vascularization have been revealed, which indicates the multifactorial nature of CCRC development and the significant role of angiogenesis in this process. It should be taken into account that patients with CCRC may have impaired vessel formation even before tumor development. To evaluate normal and pathologic angiogenesis, a pathohistologic study using immunohistochemistry is certainly necessary. Due to the significant role of angiogenesis in the development and course of CCRC, the use of drugs that suppress the formation of the vascular network in the tumor is relevant and advisable. To date, many drugs have been developed and introduced into clinical practice to inhibit angiogenesis. However, such drugs have not lived up to the expectations placed due to the frequent and rapidly developing drug resistance. Timely detection of pre-tumor and tumor processes, as well as effective treatment of cancer, including CCRC, is possible only with close cooperation between pathomorphologists and oncologists.

The state of rat kidneys after injection of bone marrow multipotent stromal cells (MSC) labeled with Vybrant CM-Dil into intact or resected liver was studied by fluorescence microscopy. The main structural changes in the kidneys after MSC injection into intact and partially resected liver manifested as granular dystrophy and necrobiotic/necrotic changes in single epithelial cells of the distal tubules and collecting ducts, thrombosis of some vessels, progression of an ascending urinary tract infection (detection of dust-like fluorescent objects), which can be due to the immunomodulating or even immunosuppressive influence of MSC and their detritus. MSC injected into the intact or resected liver, as well as the products of their degradation were not detected in the kidneys at all terms of observation. After injection of MSC into partially resected liver, manifestations of bacterial contamination of the renal medulla appeared later. The injection of MSC into the liver can be complicated by thrombosis of the renal vessels, which should be taken into account when using this administration route in the cell therapy., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature.)

The possibility of dissemination of bone marrow multipotent stromal cells stained with Vybrant CM-Dil after injection into an intact and resected liver was studied using luminescence microscopy. Labeled cells were found in the kidneys, spleen, lungs, axillary, mesenteric, and inguinal lymph nodes. We observed dissemination of multipotent stromal cells and their detritus throughout the body that occurred only after filtration in the lungs, where most cells underwent destruction. Perivascularly located macrophages in various organs can phagocytize multipotent stromal cells and their detritus from blood vessels. The content of objects labeled with Vybrant CM-Dil in distant organs was significantly lower after multipotent stromal cell injection into the resected liver, which was associated with the deposition of cells in the damaged area of the organ and their partial entry into the abdominal cavity., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

Light luminescent microscopy was used to study the distribution of extracellular microvesicles with PKH26-stained membranes secreted by placenta-derived mesenchymal stromal cells in the uterine tissues at different terms after injections to intact rats and after abdominal delivery (a model of cesarian section). Microvesicles migrated through the uterine tissues and were detected for at least 8 days after injection. In some cases, microvesicles were more numerous in the uterus after cesarian section modeling, which can be related to blockade of microcirculation and lymph flow due to inflammation accompanying surgical intervention. The content of microvesicles in the uterine tissues gradually declined due to macrophage phagocytosis and, probably, due to their migration into the vascular bed. Despite their size, properly stained extracellular microvesicles can be detected by light microscopy in tissues after injections.

The minimum and maximum indicators of the length, width, area or volume of organs and structures in the lower urinary tract can normally vary up to 2-3 times. With age, at healthy women the absolute and relative length of the urethra, the urethrovesical angle, and the inclination of the urethra do not change. Both smooth and striated muscle tissues, which are part of various departments of the female urethra, undergo atrophy during the aging process. Smooth muscle tissue is less variable with age, but striated muscle symplasts are sometimes completely absent in urethral biopsies from elderly patients. With age, the vascularization and density of the innervation decrease in the urethral structures, but the content of connective tissue in the external urethral sphincter increases. Urinary tract mobility at young women is more pronounced than at older women. The apparent insufficiency of modern investigations about age-related changes in the lower urinary tract indicates the relevance and need to continue studying of the organ and tissue transformation in the urinary system during aging, this may be important for determining the etiology and pathogenesis of some pathological conditions, such as stress urinary incontinence, as well as for differential diagnosis between age norm and pathology.

The researches devoted to postoperative liver regeneration and influence in this process were analyzed. Liver injury is followed by hypertrophy of residual liver parenchyma. The use of various cytokines is perspective for activation, acceleration and inhibition of liver recovery. Cellular technologies in the treatment of liver diseases can affect its repair. Moreover, these methods could make unnecessary resection and transplantation of liver in certain cases. It is generally accepted that the main effect of multipotent stromal cells (MSC) in liver failure is associated with their differentiation to the cellular elements of this organ. At the same time, recent reports revealed that MSC injection to the liver is followed by their quick death, dissemination to other organs and tissues or even elimination from the organism. Regeneration of non-parenchymal structures (vascular network and bile ducts) should be considered in addition to functional recovery of liver parenchyma after resection. Clarification of indications and contraindications for MSC therapy, as well as prevention of possible complications associated with cellular technologies are required.

Hemorrhagic changes after subcutaneous injection of autologous bone marrow multipotent mesenchymal cells with transfected GFP gene and additionally stained cell membranes to WAG rats in the projection of ligated femoral vein were studied by fluorescent microscopy. Hemorrhages in tissues with experimental acute local venous occlusion were caused by a combination of venous hypertension with inflammation around the foreign body - the ligature used for ligation of the vein. Fibrin found in tissues together with erythrocytes in the hemorrhages could stimulate the formation of granulations and new vessels instead of damaged or thrombosed ones. Multipotent mesenchymal stromal cells and their detritus getting into the regional lymph nodes initiated immune reactions morphologically confirmed by stubborn hypertrophy and hyperplasia of the lymphoid nodules, hemorrhages, and manifest diapedesis of erythrocytes to the organ parenchyma and sinus system.

Changes in the muscular tissue after subcutaneous injection of autologous bone marrow multipotent mesenchymal stromal cells transfected with GFP gene and additionally stained with cell membrane dye Vybrant CM-Dil in the projection of ligated femoral vein were studied by light microscopy with luminescence. Stromal cells injected through the skin can appear not only in the damaged tissue where acceleration of regeneration processes is required, but also in intact structures located in superficial or deeper layers. In intact muscular tissue, stromal cells spreading in the perivascular tissue initiate inflammation and migration of macrophages, activate and even trigger sclerotic processes due to differentiation into connective tissue cells (fibroblasts) and stimulation of proliferation and collagen synthesis by host fibroblasts. Injected multipotent mesenchymal stromal cells are gradually phagocytized by macrophages.

Autologous multipotent mesenchymal stromal cells (MMSC) of bone marrow origin with transfected GFP gene and additionally stained cell membranes were injected to rats through the skin in the projection of ligated femoral vein. The results were evaluated by fluorescent microscopy. No signs of MMSC incorporation into the wall of ligated vessel or reorganized collaterals were detected. Angiogenesis processes involving MMSC were detected in experimental rats within just 4 days and progressed until week 2 postinjection, mainly in granulations at the site of surgical intervention and the cicatrix forming there. Injected MMSC completely formed all tunics of the new vessels and incorporated in the vessels forming from the recipient cells. MMSC and the objects created from them were gradually eliminated with participation of macrophages and replaced by structures formed from the recipient cells.

The author name G. A. Chastikina should read G. A. Chastikin.

The peculiarities of tissue sclerosis after injection of autologous bone marrow multipotent mesenchymal stromal cells transfected with GFP gene and stained with Vybrant CM-Dil cell membrane dye were studied by light microscopy with luminescence. The surgical intervention consisting in ligation of the great vein was followed by tissue sclerotic transformation caused by direct damage and chronic inflammation caused by the presence of slowly resorbed ligature. Injection of stromal cells after this intervention led to formation of more extensive scar. This can attest to the possibility of stromal cells differentiation into connective tissue cells, fibroblasts, and stimulation of proliferation and collagen synthesis by host fibroblasts. A decrease in the volume of dense fibrous connective tissue due to scar reorganization at latter terms cannot not excluded.

The uterine tissues of female rats (n=30) with a scarred myometrium were examined by methods of light microscopy after the delivery. 1.5-2 months after the delivery no significant differences in the parameters of blood and lymph flow in the deep layers of the endometrium, myometrium and the myometrial scar tissue were found between the intact rats, nulliparous rats with a scarred uterus, rats that gave birth after laparotomy only and those that gave birth under the conditions of myometrial scar. In the course of pregnancy and labor activity, the damage of the tissues was observed not in the uterine scar proper, but at its borders with the myometrium. This is supported by the old hemorrhages and lymphostasis phenomena, greater number of lymphocytes, neutrophils, monocytes, macrophages and erythrocytes. In determining the indications and contraindications to vaginal childbirth in women with scarred uterus it is necessary to examine not only the scar proper, but also its border with the myometrium. The myometrial scar by itself, is not an absolute contraindication to vaginal delivery, the natural delivery is feasible in the absence of cavities with liquid and hemorrhages in the tissues of the uterine scar and at its border with myometrium.

Morphological changes in tissues adjacent to the implant were studied 1, 2, 6, and 12 months after implantation of biodegradable suture materials (catgut thread, DemeTECH polyfilament thread, and Surgilactin monofilament thread) into subcutaneous fat of rats. Tissue reaction to implantation of different suture materials developed as usual in response to a wound process and to a foreign body. By the end of month 1. the stage of traumatic perifocal inflammation was replaced in all groups by the proliferative phase with formation of new vessels and connective tissue. A trend to reduction of the productive inflammation activity from month 1 to month 12 was noted. Complete degeneration of the material after 12 months with complete recovery of the histoarchitecture of the adjacent tissues (restitution) was detected only after implantation of DemeTECH polyfilament thread.

Polylactide degradation processes after its implantation into the subcutaneous fat of rats were studied by microscopy. After implantation polylactide was encapsulated in connective tissue. If a fragment of polylactide had sharp edges, injuring the tissue, a thick capsule formed with pronounced inflammatory infiltration and sclerosis of adjacent tissues. If the implant had no sharp edges, the capsule was thin and the level of inflammation the minimum. Foreign body giant cells were found in the capsule and near it in all cases. The activity of the inflammatory process gradually reduced over 6 months. The intensity of inflammation sharply increased by the 12th month after implantation, when activity of phagocyte enzyme and deformation by the capsule led to fragmentation or liquefaction of polylactide.

The method of light microscopy was used to study the reactions of the surrounding tissues to the implantation of non-degradable surgical materials (prolene 3/0 thread made from polypropelene, the composite grid made from polypropelene or polyester with polylactic acid) in the subcutaneous adipose tissue of rats 1, 2, 6 and 12 months after grafting. No less than 6 rats were examined in every time point. It was shown that the tissue reactions to implantation of different non-degradable surgical materials follows the general pattern, characteristic of wound process and foreign body reaction. By the first month of observation in both groups of animals the stage of traumatic perifocal inflammation was replaced by the proliferative phase with the formation of new blood vessel and connective tissue. The tendency to reduction of the activity of productive inflammation was observed from the 1st to the 12th month together with the increased fibrous scar transformation of the granulation tissue.

Tissue reactions, accompanying the degradation processes of polylactide (PLA) implants after their placement into the subcutaneous tissue, were studied by the methods of light microscopy in 6 month-old Wag rats (n=24) weighing 180-200 g. It was found that PLA implants became encapsulated by connective tissue. If the implant or its fragment had sharp margins that damaged the tissues, a thick capsule was formed with a distinct inflammatory infiltration and the sclerosis of the surrounding tissues. If the implant had no sharp margins, the capsule was thin, and the activity of inflammation was minimal. In all cases, the giant cells of foreign body type were present in the capsule and next to it. Gradually, during 6 months, the activity of inflammatory process subsided. Inflammation sharply increased 12 months after the implantation, when, as a result of effect of enzymes released by phagocytes and deformation by a capsule, PLA implants were either fragmented or is liquified. PLA-based materials are not totally biodegradable, and may persist in the body for a long time.

Remodeling and cytograms of pararectal lymph nodes were studied in patients with rectal cancer after neoadjuvant therapy by different protocols. Radiotherapy and its combination with chemotherapy lead to an increase in the volume of connective tissue components and significant reduction of the volume density of lymphoid follicles without germinative centers. The counts of dividing cells, immunoblasts, and plasmoblasts in various compartments of the pararectal lymph nodes changed more significantly after radiotherapy, while changes in the count of monocytes and neutrophils were more pronounced after cytostatic therapy combined with exposure to ionizing radiation. These differences can be explained by the systemic toxic effect of chemotherapeutic drugs and primarily local cytotoxic effects of radiotherapy manifesting largely at the site of exposure.

Stimulation of release of FITC-dextran endocytosed in the liver by an injection of hypertonic sucrose led to the appearance of a less pronounced and prolonged peak (with the maximum at min 15-25) at later terms after injection of the marker (30 days). Biliary release of FITC-dextran was 4-9-fold accelerated on days 1-14 in comparison with the constitutive release, and after 30 days it was accelerated 19-fold, which reflects high capacity of the long storage compartment to stimulated release of FITC-dextran into the bile.