Structural Changes in Rat Hepatocyte Nucleolus under Nucleolar Stress Caused by Hypothermia.

Structural changes in rat hepatocyte nucleoli were studied during deep hypothermia simulated by immersion in water at 5°C for 40 min (ambient air temperature 7°C). In comparison with the control, phenomena of nucleolar stress occurred in rats during hypothermia: the number of fibrillar centers (FC) per nucleus (by 1.7 times) and per nucleolus (by 1.6 times), nucleolonemal nucleoli per nucleus (by 2.8 times), and the relative content of nucleolonemal nucleoli per nucleus (by 2.6 times) significantly decreased (p=0.0000001); the number of FC per nucleolonemal nucleolus also decreased by 1.4 times (p=0.01). In the hepatocyte nuclei, we observed an increase in the relative content of transitional type nucleoli per nucleus (by 1.3 times; p=0.01), the number of FC per transitional type nucleolus (by 1.4 times; p=0.003), the content of free FC per nucleus (by 3 times; p=0.00004), and the percentage of free FC per nucleus (by 3.5 times; p=0.00004). These changes can be considered as compensatory and adaptive reactions, and transitional type nucleoli can be attributed to the "reserve" nucleolar pool.

Ultrastructural Myocardial Reorganization during Experimental Treatment with Doxorubicin and Atorvastatin.

We studied ultrastructural reorganization of the myocardium in Wistar rats treated with doxorubicin (single intraperitoneal injection in a dose of 15 mg/kg) and atorvastatin (daily intragastric administration in a dose of 20 mg/kg for 7 days) individually and in combination. It was found that doxorubicin administered alone or in combination with atorvastatin induces disturbances of varying severity in cardiomyocyte ultrastructure indicating the development of regenerative and plastic myocardial insufficiency. In case of isolated administration of atorvastatin, lytic changes in myofibrils, increased autophagic processes, and segregation of the fibrillar and granular components in the nucleoli appeared in the ultrastructure of some cardiomyocytes with increasing the observation period. Ultrastructural stereological analysis revealed a tendency to a decrease in the volume density of myofibrils and mitochondria in all experimental groups in comparison with the control.

Monooxygenase System and NO Metabolism in Liver Microsomes of Rats with Toxic Hepatitis and the Effect of Sesquiterpene Lactones.

We analyzed changes in activities of enzymes of phases I and II of xenobiotic biotransformation and parameters of NO metabolism in liver microsomes of rats with toxic CCl4-induced hepatitis after a 14-day course of sesquiterpene lactones from Artemisia leucodes (10 mg/kg). It was found that toxic hepatitis was associated with significant inhibition of NADPH-cytochrome c-reductase, benzo(a)pyrene hydroxylase, and NADPH-diaphorase, reduced cytochrome P-450 content, and enhanced induction of nitrate/nitrite reductase with accumulation of NO metabolites in the liver. Administration of sesquiterpene lactones stimulated activity of the studied components of the cytochrome P-450 system and promoted recovery of the NOergic system components; the effects were most pronounced in 7 and 14 days after treatment.

[Molecular mechanisms of the cardiotoxic action of anthracycline antibiotics and statin-induced cytoprotective reactions of cardiomyocytes]. / Molekuliarnye mekhanizmy kardiotoksicheskogo deistviia antratsiklinovykh antibiotikov i statin-indutsirovannykh tsitoprotektornykh reaktsii kardiomiotsitov.

The manifestation of the side cardiotoxic effect of anthracycline antibiotics limits their use in the treatment of malignant processes in some patients. The review analyzes the main causes of the susceptibility of cardiomyocytes to the damaging effect of anthracyclines, primarily associated with an increase in the processes of free radical oxidation. Currently, research is widely carried out to find ways to reduce anthracycline cardiotoxicity, in particular, the use of cardioprotective agents in the complex treatment of tumors. Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) have been shown to improve the function and metabolism of the cardiovascular system under various pathological impacts, therefore, it is proposed to use them to reduce cardiotoxic complications of chemotherapy. Statins exhibit direct (hypolipidemic) and pleiotropic effects due to the blockade of mevalonic acid synthesis and downward biochemical cascades that determine their cardioprotective properties. The main point of intersection of the pharmacological activity of anthracyclines and statins is the ability of both to regulate the functioning of small GTPase from the Rho family, and their effect in this regard is the opposite. The influence of statins on the modification and membrane dislocation of Rho proteins mediates the indirect antioxidant, anti-inflammatory, endothelioprotective, antiapoptotic effect. The mechanism of statin inhibition of doxorubicin blockade of the DNA-topoisomerase complex, which may be important in preventing cardiotoxic damage during chemotherapy, is discussed. At the same time, it should be noted that the use of statins can be accompanied by adverse side effects: a provocation of increased insulin resistance and glucose tolerance, which often causes them to be canceled in patients with impaired carbohydrate metabolism, so further studies are needed here. The review also analyzes data on the antitumor effect of statins, their ability to sensitize the tumor to treatment with cytostatic drug. It has been shown that the relationship between anthracycline antibiotics and statins is characterized not only by antagonism, but also in some cases by synergism. Despite some adverse effects, statins are one of the most promising cardio- and vasoprotectors for use in anthracycline cardiomyopathy.

Features of Myocardial Remodeling and Changes in the Blood Lipid Spectrum in Experimental Doxorubicin-Induced Cardiomyopathy and Atorvastatin Administration.

Structural myocardial reorganization and changes in the blood lipid spectrum in rats were studied after administration of a single sublethal dose of doxorubicin (15 mg/kg) alone and in combination with atorvastatin (20 mg/kg/day over 7 days). It was established that doxorubicin induced the development of dyslipidemia in experimental animals (the concentrations of total cholesterol, triglycerides, and VLDL increased by 2.2, 2.0, and 1.96 times, respectively; the atherogenic coefficient increased by 3.4 times by day 7 of the experiment). In animals with experimental anthracycline cardiomyopathy treated with atorvastatin, the concentrations of the main components of the blood lipid spectrum increased less markedly. Atorvastatin alone induces moderate myocardial remodeling in comparison with more pronounced changes in the structural organization of the myocardium in rats treated with doxorubicin alone. Course treatment with atorvastatin under conditions of doxorubicin-induced cardiomyopathy reduced the severity of myocardial remodeling: the decrease in the volume density of cardiomyocytes and the increase in the volume density of the connective tissue were less pronounced in the dynamics of the experiment.

Immunistochemical Analysis of the Expression of TGFß, Galectin-1, Vimentin, and Thrombospondin in Gastric Cancer Associated with Systemic Undifferentiated Connective Tissue Dysplasia.

We performed immunohistochemical analysis of the expression of TGFß, galectin-1, vimentin, and thrombospondin in the mucosa in gastric cancer of diffuse and intestinal type associated with systemic undifferentiated connective tissue dysplasia. In diffuse gastric cancer, both with and without association with connective tissue dysplasia, a higher level of expression of TGFß, galectin-1, vimentin, and thrombospondin in the tumor was detected in comparison with the perifocal and tumor zones in intestinal gastric cancer, which may reflect the pathogenetic peculiarities of the two histotypes of gastric cancer. Intestinal type of gastric cancer associated with connective tissue dysplasia is characterized by a high level of expression of galectin-1 and vimentin in the perifocal zone and TGFß in the tumor zone. The pattern of expression of the studied markers can reflect both the pathogenetic peculiarities of the two histotypes of gastric cancer and peculiar expression of some growth factors, cytoskeleton proteins, and matrix-cell proteins associated with undifferentiated connective tissue dysplasia which may contribute to epithelial-mesenchymal transition.

Structural Analysis of the Myocardium in Experimental Anthracycline-Induced Cardiomyopathy Combined with Adrenergic Stimulation.

We studied dynamic changes in the total number of cardiomyocytes and the character of structural lesions in the myocardium in rats with modeled anthracycline-induced cardiomyopathy provoked by a single injection of doxorubicin in a dose of 10 mg/kg alone or in combination with subsequent adrenergic stimulation. The injections of epinephrine during the development of anthracycline-induced cardiomyopathy resulted in more pronounced loss of body weight, stronger decrement of the heart weight, and more severe decrease of the cardiomyocyte count in comparison with the corresponding changes induced by doxorubicin alone. The basic lesions of cardiomyocytes in anthracycline-induced cardiomyopathy are the lytic alterations and subsegmental contractures; in contrast, combined use of doxorubicin and epinephrine provoked degree II and III contractures. The revealed necrobiotic changes of cardiomyocytes resulted in their death and pronounced decrease of their number at the initial terms of the study. Hypertrophy observed at later terms of the experiments in parallel with partial recovery of cardiomyocyte number reflected the development of regenerative and adaptivecompensatory processes induced by massive death and elimination of the parenchymatous cells (up to 36-37% of population).

Intracellular Reorganization of Cardiomyocytes in Dyslipidemic Cardiomyopathies.

The study examined the myocardial ultrastructural alterations in rats maintained on various atherogenic diets. It revealed the complex ultrastructural alterations of cardiomyocytes and endotheliocytes (including the lytic and destructive changes of the intracellular organelles, upregulation of the autophagocytosis in the cardiomyocytes, and necrobiosis with apoptosis of endotheliocytes) reflecting the cytopathic features of circulating cholesterol and lipoproteins, whose elevation determined the intensity of destructive processes. The revealed peculiarities in the changes of lipid inclusions (their osmiophilic transformation) in cardiomyocytes can be provoked by entry of cholesterol into the cells and its further metabolic modifications. During moderate dyslipidemia, the cardiomyocytes demonstrated the ultrastructural signs of induction of intracellular regeneration (marked with the clusters of polysomes in the intermyofibrillar and subsarcolemmal spaces with appearance of neogenic myofilaments) and upregulated pinocytotic activity. In all cases, up-regulated autophagocytosis in cardiomyocytes was accompanied by accumulation of myelin- and vacuole-like structures in the intercellular spaces and capillary lumens paralleled with appearance of activated forms of macrophages and fibroblasts in the myocardium.

Role of Matrix Metalloproteinase-2 in the Development of Cyclophosphamide-Induced Cardiomyopathy.

Immunohistochemical assay was employed to determine localization of MMP-2 in cardiomyocytes of WAG rats and changes in MMP-2 expression during modeled cardiomyopathy induced by single intraperitoneal injection of cyclophosphamide (125 mg/kg) alone or in combination with preventive intraperitoneal administration of an equal dose of asparcam-L (potassium-magnesium asparaginate) 30 min prior to the cytostatic. In the myocardium of control and experimental rats, MMP-2 was mostly located in cardiomyocyte nuclei. During the development of cyclophosphamide-induced cardiomyopathy (in 3 days after injection), the index of MMP-2-positive cardiomyocyte nuclei increased by 76%. In contrast to control hearts, MMP-2 was also expressed in the cardiomyocyte sarcoplasm. Preventive injection of asparcam-L moderated the cardiotoxic effect of cyclophosphamide, which manifested in less pronounced increase in the volume density of cardiomyocytes with lytic changes (by 42%) and index of MMP-2+ cardiomyocyte nuclei (by 23%) in comparison with the rats exposed to cyclophosphamide alone.

Expression of Flk-1 and Cyclin D2 mRNA in the Myocardium of Rats with Doxorubicin-Induced Cardiomyopathy and after Treatment with Betulonic Acid Amide.

The expression of VEGFR2 (Flk-1, according to immunohistochemistry) and of cyclin D2 mRNA (according to real-time PCR) in the myocardium of rats is studied in doxorubicin-induced cardiomyopathy and in response to betulonic acid amide. Doxorubicin alone and in combination with betulonic acid amide causes after 3 days a manifest reduction of cyclin D2 mRNA expression (by 38 and 63%, respectively), while injection of betulonic acid amide alone causes a 23-fold increase of cyclin D2 mRNA expression. An increase of cyclin D2 mRNA expression has been detected in all experimental groups after 14 days of experiment, the most pronounced in response to betulonic acid amide (63 times). The expression of Flk-1 in cardiomyocytes increases significantly in response to both chemical agents starting from day 3 of experiment. These results indicate that doxorubicin and betulonic acid amide induce cytoprotective reactions in the myocardium, first at the intracellular, then at the cellular levels.

Immunohistochemical Study of the Expression of Vascular Endothelial Growth Factor Receptor-2 (KDR/Flk-1) during Myocardial Infarction.

Immunohistochemical study showed that vascular endothelial growth factor receptor-2 (KDR/Flk-1) is expressed in the cytoplasm of viable cardiomyocytes, mononuclear cells of the granulation tissue, and smooth muscle cells of intramural arteries at all terms of postinfarction reparative regeneration. Cardiomyocytes were highly heterogeneous by the intensity of staining. This feature was typical of cardiomyocytes in the ischemic area (no staining), as well as within various muscle bundles and one muscle bundle. KDR/Flk-1 expression was revealed in mononuclear cells of the necrotic area (macrophages and fibroblast cells). The distribution of KDR/Flk-1 remained practically unchanged with lengthening of the postinfarction period (more than 7 days). The increase in the heterogeneity of cardiomyocyte staining under these conditions illustrates variations in the intensity of cytoprotective processes during ischemia. KDR/Flk-1 expression in smooth muscle cells of intramural arteries was shown to increase in a later period of observations.

High Antimetastatic Activity of Platin Liposomal Form after Lyophilization and Storage.

Antimetastatic activity of Platin in lyophilized liposomes stored for 7 years after fabrication was evaluated. The main flaw of liposomes as vehicles for drug delivery to the tumors is their high affinity for the liver, which accumulates a great amount thereof. This property of liposomes can be used for adjuvant therapy of operable primary tumors metastasizing to the liver. It is shown on the model of mouse GA-1 tumor metastases in the liver that platinum(II) complex compound Platin in phosphatidylcholine-cholesterol liposomes, stored for 7 years after lyophilization, causes complete cure of 40% animals, while free Platin prolongs the lifespan of mice with tumors by only 31.7% vs. control (no treatment).

Cardiotoxic and Dyslipidemic Effects of Doxorubicin and Betulinic Acid Amide.

Changes in the blood lipid spectrum and structural reorganization of the rat myocardium in response to injection of a single sublethal dose of doxorubicin (7 mg/kg) alone and in combination with course administration of betulonic acid amide (100 mg/kg/day for 14 days) were studied. Betulinic acid amide in the specified dose exhibited less pronounced cardiotoxic (necrobiotic impairment of cardiomyocytes) and dyslipidemic (increase of cholesterol and triglyceride levels) effects in comparison with doxorubicin. Combined treatment with betulinic acid amide and doxorubicin led to more pronounced remodeling of the myocardium, which was shown by a significant increase of the connective tissue/cardiomyocyte volume ratio detected by day 14 of the experiment.

Clinical Morphological Studies of Myelofibrosis with Different Types of Bone Marrow Involvement in Patients with Chronic Lymphocytic Leukemia.

Clinical-morphological study of myelofibrosis was carried out in patients with chronic lymphocytic leukemia at the debut of the disease. Trephinobiopsy specimens of the ileac bone, aspirated specimens of the bone marrow, and peripheral blood smears were studied in 80 patients. Chronic lymphocytic leukemia was associated with myelofibrosis of different severity in 22.5% cases. Morphometric analysis of trephinobiopsy specimens showed that the severity (histology and dissemination) of myelofibrosis correlated with the type of tumor involvement of the bone marrow. Focal tumor involvement of the bone marrow predominated in trephinobiopsy specimens from patients without myelofibrosis, while patients with myelofibrosis developed mainly diffuse tumor infiltration, associated with the greatest dissemination of the initial and manifest myelofibrosis. No myelofibrosis was found in patients with interstitial tumor involvement of the bone marrow. The severity of the initial and manifest myelofibrosis directly correlated with the tumor involvement of the bone marrow and peripheral blood. Evaluation of the prognosis showed that initial myelofibrosis was associated with disease standing of 5.5 months, while manifest condition with a disease of 8.5 months and longer.

Stimulation of Cardiomyocyte Regeneratory Reactions under Conditions of Cytopathic Hypercholesterolemia.

The regeneratory reactions of cardiomyocytes in the heart under conditions of cytopathic exposure to hypercholesterolemia and during verapamil treatment were studied by immunohistochemical detection of proliferation marker Ki-67 and evaluation of cardiomyocyte count. A 30-day exposure of rats to atherogenic diet led to an increase of Ki-67+ cardiomyocytes by 14.5-16.7 times (p<0.05). The Ki-67 label index in cardiomyocytes remained higher than normally (8-9-fold; p<0.05) after 64 days. It remained elevated (8-11-fold; p<0.05) after verapamil treatment. Evaluation of cardiomyocyte count and of their nuclear status detected various regeneratory strategies: increase of the total cardiomyocyte count, with increase of the percentage of mononuclear cardiomyocytes (particularly in response to verapamil in group 1 rats); decrease of total cardiomyocyte count with increase of the percentage of multinuclear cardiomyocytes (particularly in group 2 rats in response to verapamil).

Immunohistochemical Analysis of MMP-2 Expression in the Myocardium During the Postinfarction Period.

Immunohistochemical analysis revealed 2.5-fold increased of expression MMP-2 in myocardium samples during the early period (up to 3 days) of postinfarction reparative regeneration. During this period, MMP-2 was detected mainly in monocytes/macrophages circulating in the blood and migrating to the necrotic zone, while expression in the intermuscular and perivascular connective tissue was lower. At later terms, with development of large focal and diffuse cardiosclerosis, MMP-2 expression significantly decreased (to the initial level) and was detected mainly in the foci of intermuscular and perivascular fibrosis, its area in the sections increased by 1.8 times. Evaluation of MMP-2 expression in the blood vessels showed that the immunohistochemical reaction was the most pronounced in the walls of new sinusoidal vessels and the minimum in the intramural arteries of medium diameter. These results attest to an important role of MMP in connective tissue remodeling (proteolytic degradation) during the early period of postinfarction reparative regeneration. The decrease in MMP-2 expression observed at later terms correlated with myocardial fibrosis progression.

Expression of ryanodine receptor mRNA and sarcoplasmic Ca²âº-ATPase mRNA in the myocardium and intracellular reorganization of cardiomyocytes in dyslipidemia and during verapamil treatment.

In experiments on rats, atherogenic diet led to hypercholesterolemia, while addition of verapamil to the diet led to the development of hypertriglyceridemia in these animals. Dyslipidemia induced significant changes in the cardiomyocyte ultrastructure (lytic changes in myofibrils and sarcoplasmic matrix and aggravation of autophagocytosis) that were most pronounced after addition of mercazolyl alone to the diet. After 30-day atherogenic diet, we observed a decrease in the relative content of RyR2 mRNA (by 67-73%, p<0.01) and SERCA2a mRNA (by 75-91%, p<0.01) in the myocardium. In 64 days these parameters remained reduced: by 64-72% (p<0.05) and 54-62% (p<0.05), respectively. Verapamil treatment reduced the severity and number of lytic lesions in cardiomyocytes, induced considerable glycogen accumulation in the sarcoplasm and its sequestration, promoted normalization, and prevented pronounced decrease of the relative RyR2 mRNA and SERCA2a mRNA in rat myocardium.

Remodeling of myocardium in rat with chronic dyslipidemia and under conditions of verapamil treatment.

The type and intensity of remodeling (structural reorganization) of the myocardium in Wistar rats were studied under conditions of experimental chronic dyslipidemia and verapamil treatment. Long (64 days) atherogenic diet caused dyslipidemia and led to reduction of the heart percent weight. The cytopathic effect of dyslipidemia manifested in more intense lytic injuries of cardiomyocytes, development of diffuse and small focal cardiosclerosis under conditions of manifest circulatory disorders. Remodeling of the myocardium during various periods of the experiment manifested in a higher connective tissue/cardiomyocyte volume ratio (by 74% after 30 days and by 58-62% after 64 days of experiment). Verapamil injection promoted attenuation of lytic changes in cardiomyocytes and in fibroplastic reactions of the stroma, but failed to prevent them completely.

Proliferative activity of cadriomyocytes in chronic hypercholesterolemia.

We studied proliferative activity of cardiomyocytes (using proliferation marker Ki-67) and compared it with their total number in the heart under conditions of experimental chronic hypercholesterolemia and its combination with hypothyroidism. It was found that Ki-67-positive cells are primarily located in the subepicardial layer near the heart base in both intact and experimental animals. Replicative cardiomyocyte pool in intact rats constituted 1.67 ± 0.33‰ of the total cardiomyocyte population; after 68-day atherogenic diet with exogenous cholesterol alone, the replicative cardiomyocyte pool decreased by 16 % (to 1.40 ± 0.24‰). Treatment with mercazolil against the background of exogenous cholesterol increased this parameter by 40 % (to 2.33 ± 0.88‰). Changes in replicative activity of cardiomyocytes correlated with their total number in the heart and organ weight. We conclude that replicative cardiomyocyte pool primarily includes non-terminally differentiated cardiomyocytes (small mononuclear cardiomyocytes) and their proliferation maintains the total number of cardiomyocytes in the heart under conditions of cytopathic influences and provides the basis for physiological and reparative regeneration of the myocardium.

Expression of mRNA of apolipoprotein E, apolipoprotein A-IV, and matricellular proteins in the myocardium and intensity of fibroplastic processes during experimental hypercholesterolemia.

The expression of mRNA of matricellular proteins (osteopontin, and lumican), apolipoproteins E and A-IV, and microsomal triglyceride transfer protein, and the intensity of fibroplastic processes were studied in the myocardium of rats during experimental chronic hypercholesterolemia. We have found that the development of chronic hypercholesterolemia was followed by an increase in volume density of interstitial connective tissue in the myocardium reflecting the activation of fibroplastic processes. A slight positive correlation was observed between the connective tissue density in the myocardium and expression of osteopontin mRNA (r=0.408) and lumican mRNA (r=0.470). Myocardium remodeling during hypercholesterolemia is realized against the background of increased expression of apolipoproteins E and A-IV mRNA and microsomal triglyceride transfer protein mRNA involved in transport and metabolism of lipoproteins in several tissues and probably play a pivotal role in the regulation of lipoprotein transport and metabolism in the myocardium. We concluded that the increase in the expression of apolipoproteins (E and A-IV) and microsomal triglyceride transfer protein play adaptive and compensatory role and is related to the increase in lipoprotein utilization by macrophages.