HELICOBACTER PYLORI AND GALLBLADDER PATHOLOGIES: IS THERE A CAUSE-AND-EFFECT RELATIONSHIP?

The relationship between Helicobacter pylori infection and gallbladder diseases, particularly cholecystitis and gallbladder polyps, remains unclear. This study aimed to investigate the presence of H. pylori in gallbladder tissues and its potential role in gallbladder pathologies, as well as to examine the expression of chemokines CXCL2 and CXCL5 in these conditions. MATERIAL AND METHODS: A total of 137 laparoscopically excised gallbladders were analysed through histological examination, PCR for H. pylori-specific DNA, and quantitative real-time PCR for CXCL2 and CXCL5 gene expression. The study cohort included patients with acute calculous cholecystitis, chronic calculous cholecystitis, and gallbladder polyps. RESULTS: H. pylori was detected in 30.7% of cases by histological methods and 42.3% by PCR. Elevated expression of CXCL2 and CXCL5 was observed in 62% and 57.7% of cases, respectively, with a higher prevalence in acute cholecystitis compared to chronic conditions. However, no statistically significant association was found between H. pylori presence and the forms of cholecystitis, as well as between H. pylori presence and chemokine expression in gallbladder. CONCLUSIONS: The study did not establish a direct link between the presence of H. pylori infection and forms of gallbladder pathologies. The findings suggest that other factors other than H. pylori may contribute to the upregulation of CXCL2 and CXCL5 in gallbladder diseases. Further research is needed to elucidate the complex interactions between H. pylori, chemokines, and gallbladder pathologies.

Features of Ductular Reaction in Rats with Extrahepatic Cholestasis.

Ductular reaction develops during liver regeneration, fibrosis, and carcinogenesis. However, the types, stages of formation, and topography of ductular profiles in various pathologies remain insufficiently studied. Using the model of common bile duct occlusion, we showed that the number and topography of ductular profiles are closely related to the duration of biliary obstruction. The ductular profiles can be located inside the portal tract, along the existing bile ducts, and/or intramurally, around the portal vein, periportally, inside the lobules, in the portocaval fibrous connections, in the adventitia of the hepatic veins, in the septs connecting the portal tracts, and also in the "portal plate" of the liver. The ductular profiles can be formed as a result of expansion of existing bile ducts, cholangiocyte proliferation, as well as transdifferentiation of hepatocytes and activation of mesenchymal stem cells.

LIVER EXTRACELLULAR MATRIX PECULIARITIES IN MAMMALS AND AVIANS.

Analysis of liver matrix studies makes it obvious that knowledge about the connective tissue skeleton of the liver is not systematized, the terminology is contradictory, and the question of the construction of some components sometimes causes controversy. We set a goal to study the features of the construction of the connective tissue matrix of the liver of various mammals and birds in order to identify and systematize general and specific patterns of this structure. The liver of mammals with a gallbladder (pigs, sheep) and without a gallbladder (rats) and birds (domestic chickens with a gallbladder) was studied by the methods of anatomical preparation, histology, histochemistry, histotopography, immunohistochemistry, scanning electron microscopy of corrosion replicas and fluorescence microscopy. In the liver of mammals and birds, connective tissue membranes of various thicknesses and compositions around the portal tracts and hepatic veins are revealed. These membranes are connected in various ways with each other, the liver capsule and the intralobular network of connective tissue and form an extracellular matrix, which strengthens the structure of the liver tissue and helps the organ maintain its integrity in various pathological conditions.

STRUCTURAL CHANGES IN RATS' LIVER DURING THE FIRST 2 WEEKS FOLLOWING 2/3 PARTIAL HEPATECTOMY.

Aim of study - Investigation of changes in hepatocyte size and shape and architecture of the sinusoidal network in 2-week dynamics after resection 2/3 of the liver. The experiments were performed on 16 adult male Wistar rats weighing 190-200 grams who underwent 2/3 resection of liver, while a resected portion of the liver of the same rat was considered as a control. We examined liver tissue by histological, immunohistochemical, morphometrical methods, and the architecture of the sinusoidal capillary network by electron microscopy of corrosion casts. The study was conducted in 24 hours, 48 hours, 96 hours, 1 week, and 2 weeks after surgery. The shape and size of the hepatocytes in the first and third zones of the liver acinus change with the term of the experiment. With changes in the shape and size of hepatocytes, new intercellular connections are formed, including with the involvement of atypical membrane protrusions of deformed neighboring hepatocytes. One week after regeneration, electron microscopic examination of corrosion casts reveals a network of sinusoids that spatially define lobules of different shapes and sizes, including those that appear to be a combination of two "normal" lobules. Superficial sinusoids are often markedly dilated (up to 25 µm). In addition, small-diameter (6-7µm) sinusoidal casts with a rough surface and small bud-shaped protrusions are observed in some areas, giving the line of this a zigzag shape. The existence of hepatic vein tributaries and associated with them large sinusoids, found In single areas, reveals the characteristic feature of vascular sprouting. Based on the data obtained, it can be assumed that despite the recovery of liver mass, the regeneration process is not complete. Regenerated liver undergoes a permanent process of transformation of hepatocytes' shape and size, as well as the transformation of the vascular network, which is the basis for changes in the spatial architecture of the liver lobules.

Spatial Organization of the Transport of Interstitial Fluid and Lymph in Rat Liver (Scanning Electron Microscopy of Injection Replicas).

Using the method of scanning electron microscopy of injection replicas, we studied the movement of a new injection mass between the blood microcirculation system, interstitial space, lymphatic system, and bile transport system in rat liver under normal conditions and 3 days after the occlusion of the common bile duct. The casts of the perisinusoidal spaces of Disse's after injection of the injection mass through the portal vein and common bile duct were obtained. Their direct transition not only in "leakages" structurally related to lymphatic capillaries in interlobular spaces, but also in perivascular spaces around the portal and hepatic veins. The flow of the injection mass through the perivascular spaces leads to the formation of peculiar "sheaths" around hepatic veins and components of the portal complex. The proposed approach allows effective visualization of the structural basis of interaction of various compartments of the fluid microcirculation in the liver under normal and pathological conditions.

MORPHOLOGICAL CHANGES IN THE LIVER AFTER 8 HOURS OF PRESERVATION BY MACHINE PERFUSION.

Patients with refractory cardiac arrest, who have undergone Extracorporeal Life Support (ECLS) for resuscitation, but have not achieved cardiac recovery, can be considered as potential donors (Cardiac Death Donors). In such cases, it takes time to notify and obtain the principle consent of the relatives and finalize the clinical and legal documents. During this time, prior to obtaining consent for the removal of organs, ECLS can be extended. In this case, the extracorporeal circulation implies organ preservation "in situ" until the ethical, religious and organizational problems should be decided. Correspondingly, the identification of safe time terms during which the donor organs do not suffer by the changes not compatible with transplantation is extremely important. We aimed to study the morphological changes in the liver after 8 hours of extracorporeal circulation in experiments. The investigation was performed on 6 sheep with simulated cardiac arrest and undergone 8-hours extracorporeal circulation with own blood by using of new portable perfusion apparatus, made on the basis of a universal volumetric blood pump of our own design. The device was connected to the body through the femoral artery and vein with special cannulas. The biopsy of the liver was performed before the starting of perfusion, and on 4 and 8 hours of the experiment. The histological slices were stained by H&E and were assessed by standard criteria: level of steatosis (large-droplet macrovesicular steatosis [ld-MaS] and/or small-droplet macrovesicular steatosis [sd-MaS]); mononuclear portal inflammatory cell infiltrates; bile ductular proliferation; cholestasis; venous congestion; hepatocellular necrosis. Before the perfusion, no venous congestion, hepatocellular necrosis or ld-MaS were observed; Less than 3% of cells were suffered by sd-MaS; mononuclear portal inflammatory cell infiltrates were found only in several areas. Mild mixed ld-MaS and sd-MaS was found in less than 5 % and 10% of the cells accordingly on the 4 and 8 hours after in vivo Machine perfusion. Similarly the mild venous congestion was present in 1 out of 6 livers after 4-hours perfusion and in 2 out of 6 livers after 8-hours Perfusion. The number of necrotic hepatocytes and portal triads infiltrated with mononuclear cells did not exceed 10% and 15% accordingly. However, there were no differences in the degree of biliary damage - cholestasis or ductular proliferation - correlating with the terms of the experiment. Taking into the consideration all internationally accepted criteria of donor liver histological assessment, 8-hour in vivo perfusion of the liver in Cardiac Death Donors by using of the machine of own design providing the pulsatile blood flow guarantees the satisfactory preservation of liver making it useful for successful transplantation.

DUCTULAR REACTION AT THE EARLY AND LATE STAGES OF BILIARY OBSTRUCTION: IS THE MECHANISM THE SAME?

Ductular reaction (DR) is one of the classical features of biliary obstruction in humans as well as in experimental models. It is the histological phenomenon expressed by the increased number of ductular profiles (DPs), which is especially intensively studied in rodents' model of common bile duct ligation (CBDL). However, some issues related with DR in long-term CBDL are not clear enough. The liver tissue of male Wistar rats (150-200 g) subjected to CBDL were studied histologically (H&E). The architectonics of the biliary tract was studied by investigation of the corrosion casts obtained by retrograde injection (trough CBD) the solidified mass prepared on the basis of "Protacryl M" widely implemented in orthopedic dentistry. The casts were investigated by electro-optic device ProScope-HR with magnification X10, X50 and X200. DR accompanying CBDO is featured by the development of new DPs, the number of which is permanently increased in association with the prolongation of the terms of Cholestasis. DPs continue to develop in all areas of liver lobules - from portal/periportal region up to the regions containing central veins (hepatic veins tributaries of small calibers). The part of DPs has wide lumens, while the lumens of another part of DPs are hardly notable. In spite of evident ductular metaplasia of hepatic tissue, the small groups of normal by form and structure hepatocytes forming the separate small islets could be revealed. Histological features of these hepatocytes support the proposition that these cells maintain the functional activity on the 4th-5th weeks after CBDO. The results of investigations of biliary corrosion casts on the 4th and 5th weeks of CBDO show that solidifying mass cannot reach the small ducts/ductules and especially bile canaliculi. This fact confirms the interruption of ductular-canalicular junctions (IDCJ). We propose that due to IDCJ the increased pressure in preserved bile canaliculi should stipulate the mitotic activity and biliary trans-differentiation of hepatocytes on the late terms of CBDO and support the generation of ductal-like structures and appearance of new DPs. These ductules generally are not drained into the entire biliary tree.