The role of vascular injury within the conditions of choline deficiency in rats with scopolamine-induced alzheimer's type dementia

Background. The relationship between choline deficiency and vascular dysfunction continues to be relevant in the study of Alzheimer's disease. Objective. To study the morphological characteristics of vascular injury within the conditions of choline deficiency in rats with scopolamine-induced Alzheimer's type dementia. Methods. The experiment was performed on 48 WAG population male rats weighing 180-230 gr. Rats from groups Scop-14, Scop-14-SC, Scop-28, Scop-28-SC were injected intraperitoneally with scopolamine (Scop) butylbromide at a dosage of 1 mg/kg of body mass during 14 and 28 days and intravenously with mesenchymal stem cells (SC) at a single dosage of 500000 cells per 1 rat. Control animals (gr.C) were injected with 0.9% sodium chloride. Brain slides were stained with Congo-red and gallocyanine-chromium alum according to Einarson's method for total nucleic acids. The VEGF, E-cadherin expression was immunohistochemically determined in the brain cells cytoplasm. Results. The congophilic staining of the arteries walls, a decrease in endothelial cells with low the E-cadherin expression and an increase in the number of pericytes in the capillary wall was observed in the experimental groups. In gr.Scop-28 VEGF expression in endothelial cells, hippocampal neurons was greater than in gr.Scop-14. It indicated more intensive activation of angiogenesis and acetylcholine synthesis with correspondingly more pronounced vascular damage and choline deficiency. The cytoplasm of cortical neurons was diffusely labeled with VEGF antibodies in response to hypoxia, but the level of expression was almost no different from that in gr.C. In all groups, the optical density of the neuropile of the large hemispheres according to Einarson’s staining was reduced, i.e., the level of RNA in the neuronal processes was reduced. The introduction of stem cells restored the capillary wall due to young endothelial cells, reduced the VEFG synthesis in all studied cells and increased the RNA content in neuronal processes. Conclusion. The relationship between choline deficiency, neuronal process loss and vascular damage has been found. The blood vessels self-repair was occurred by substitution, after the stem cells introduction - by restitution.

Membranous Nephropathy with Lambda Light Chain Restriction: A Rare Form with Serum Negative and Tissue Positive PLA2R Ab

Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults. Subepithelial polyclonal immunoglobulin deposits and >70% M-type phospholipase A2 receptor antibody positivity are typical findings in idiopathic MN. A 58-year-old female patient was admitted with clinical presentation of nephrotic syndrome. Autoimmune diseases, infections, and malignancies were ruled out after clinical and laboratory evaluations. Diagnostic work-up revealed serum PLA2R antibody negativity and diffuse thickening of glomerular capillary wall on biopsy, while glomerular capillary wall IgG, C3, and Lambda monotypic light chain deposition and PLA2R1 positivity were detected by immunofluorescence and immunohistochemical examination, respectively. Following prednisolone treatment, creatinine and proteinuria were markedly regressed. The MN cases with a light chain deposits are rare and experience regarding their treatment are insufficient.

An Investigation of the Antigenic Characteristics of the Renal Glomerulus in the Rat

<p>The finding of a granular deposition of immunoglobulin in the kidney in experimental animal models of glomerulonephritis has been been interpreted as resulting from the random deposition of immune complexes in the glomeruli. Recent data suggests that although immune complex deposition may be an important factor in some forms of glomerulonephritis, the in situ formation of immune complexes between circulating anti-kidney antibodies and fixed glomerular capillary wall antigens may also be a significant factor in the pathogenesis of some animal models of glomerulonephritis. To examine the characteristics of discontinuously represented glomerular capillary wall antigens in the rat, monoclonal antibodies were generated against a glomerular plasma membrane fraction, depleted of glomerular basement membrane, prepared from isolated Lewis rat glomeruli. A total of 17 hybridomas, generated from the fusion of splenocytes obtained from mice immunised with the glomerular membrane fraction produced monoclonal antibodies which reacted with discontinuously represented antigens in the glomerulus and renal tubules. One further hybridoma secreted a monoclonal antibody which reacted with an antigen present on glomerular and tubular nuclear membranes. No hybridomas were produced which secreted a monoclonal antibody which reacted with linearly arrayed glomerular basement membrane antigens. Two of these monoclonal antibodies, both of the IgM subclass and code-named PH7 and SC5, produced a heavy granular glomerular staining pattern when examined by indirect immunofluorescence microscopy. Neither monoclonal antibody was kidney specific, with reactivity being demonstrated with a number of non-renal tissues. When administered intravenously to normal Lewis rats both SC5 and PH7 induced a mild proteinuric lesion. The proteinuria was not associated with histopathological changes at the light or electron microscope level. Immunoblotting experiments revealed that SC5 reacted predominantly with a protein band of 96 kDa present in detergent extracts of isolated glomeruli and glomerular plasma membranes. PH7 was shown to react with three low molecular weight proteins of 14, 13 and 11 kDa The findings of this study demonstrate the potential for a nephritogenic response to occur following the in situ formation of immune complexes between circulating anti-kidney antibodies and discontinuously arrayed non-glomerular, basement membrane glomerular capillary wall antigens characterised by granular immunofluorescence patterns,in animal models of glomerulonephritis.</p>

An Investigation of the Antigenic Characteristics of the Renal Glomerulus in the Rat

<p>The finding of a granular deposition of immunoglobulin in the kidney in experimental animal models of glomerulonephritis has been been interpreted as resulting from the random deposition of immune complexes in the glomeruli. Recent data suggests that although immune complex deposition may be an important factor in some forms of glomerulonephritis, the in situ formation of immune complexes between circulating anti-kidney antibodies and fixed glomerular capillary wall antigens may also be a significant factor in the pathogenesis of some animal models of glomerulonephritis. To examine the characteristics of discontinuously represented glomerular capillary wall antigens in the rat, monoclonal antibodies were generated against a glomerular plasma membrane fraction, depleted of glomerular basement membrane, prepared from isolated Lewis rat glomeruli. A total of 17 hybridomas, generated from the fusion of splenocytes obtained from mice immunised with the glomerular membrane fraction produced monoclonal antibodies which reacted with discontinuously represented antigens in the glomerulus and renal tubules. One further hybridoma secreted a monoclonal antibody which reacted with an antigen present on glomerular and tubular nuclear membranes. No hybridomas were produced which secreted a monoclonal antibody which reacted with linearly arrayed glomerular basement membrane antigens. Two of these monoclonal antibodies, both of the IgM subclass and code-named PH7 and SC5, produced a heavy granular glomerular staining pattern when examined by indirect immunofluorescence microscopy. Neither monoclonal antibody was kidney specific, with reactivity being demonstrated with a number of non-renal tissues. When administered intravenously to normal Lewis rats both SC5 and PH7 induced a mild proteinuric lesion. The proteinuria was not associated with histopathological changes at the light or electron microscope level. Immunoblotting experiments revealed that SC5 reacted predominantly with a protein band of 96 kDa present in detergent extracts of isolated glomeruli and glomerular plasma membranes. PH7 was shown to react with three low molecular weight proteins of 14, 13 and 11 kDa The findings of this study demonstrate the potential for a nephritogenic response to occur following the in situ formation of immune complexes between circulating anti-kidney antibodies and discontinuously arrayed non-glomerular, basement membrane glomerular capillary wall antigens characterised by granular immunofluorescence patterns,in animal models of glomerulonephritis.</p>

Demixing in the plasma created in capillary discharges with polymeric wall

The results of spectral diagnostics of erosion plasma obtained in a pulsed discharge in a capillary with an evaporating wall made of hydrogen-carbon and fluorine-carbon polymers - polymethylmethacrylate and polytetrafluoroethylene - are presented. It was found that in both cases the distribution of chemical elements along the discharge radius is highly inhomogeneous, and their concentration ratio differs significantly from that in the capillary wall. The mass of particles is a common sign characterizing the demixing degree of chemical elements and direction of diffusion flows in fluorine-carbon and hydrogen-carbon plasmas. In both cases, lightweight particles are concentrated in the central high-temperature region, while heavy ones run away onto the low-temperature peripheral region of the discharge. Estimates show that the thermal diffusion mechanism is quite capable for providing the observed demixing degree of chemical elements. Favorable conditions for thermal diffusion processes are formed in the layer adjacent to the capillary wall, where the intense dissociation of radicals occurs, and the temperature gradient reaches up to ΔT∼10 eV/mm.

On the mechanisms of damaging effect of diabetogenic chelators on the endothelium of blood capillaries in pancreatic islets

Authors showed that administration of diabetic zinc binders (DZC) to animals is accompanied not only by destruction and death of B cells, but also by the development of morphological changes in the capillaries of pancreatic islets at the site of contact with B cells (destruction of the capillary endothelium sites, change in the shape of the capillary lumen, erythrocytes adhesion, perivascular edema, hyperemia). Vascular changes are usually late complications of diabetes. To answer the question: are the described changes in islet capillaries a late complication of diabetes (1) or is it the result of the direct damaging effect of DZC (2), low doses of DZC that do not cause diabetes in animals are used, forming a toxic zinc-dithizone complex only at B-pole cells in contact with the capillary wall. It was shown that in this case, the capillary wall is damaged in the absence of diabetes, which indicates a direct damaging effect of DZC not only on B-cells but also on the endothelium of islet capillaries. This is not a direct cause of the development of these forms of diabetes, but may be accompanied by circulatory disorders in pancreatic islets and a worsening of the course of the disease.

MO694SWELLING OF PERITONEAL TISSUE DURING PERITONEAL DIALYSIS: COMPUTATIONAL ASSESSMENT USING POROELASTIC THEORY

Background and Aims Experimental studies and computational modeling show increased hydration of peritoneal tissue close to peritoneal surface after intraperitoneal (ip) administration of hypertonic dialysis fluid. This overhydration - due to fluid inflow from peritoneal cavity (driven by increased intraperitoneal pressure) and from blood (due to high interstitial concentration of osmotic agent diffusing from the cavity) - may lead to tissue swelling, as observed in experiments and in disturbed physiological conditions. We estimated the degree of swelling using linear poroelastic theory with fluid and solute transport parameters obtained from clinical studies. Method The spatially distributed model of peritoneal transport was extended by equations for tissue deformation and stress derived from linear poroelastic theory. The model describes also fluid and osmotic agent flows across tissue and capillary wall. We assumed that transport and deformation occur across a layer of tissue with initial intact width L0 and deformed width L; the deformation is described as the ratio L/L0. Transport parameters are assumed as average values estimated for intact tissue by Stachowska-Pietka (2019). As tissue stiffness (Lame coefficient) for muscle is not known, we examined stiffness ranging from 110 mmHg (connective tissue; interstitium) to 700 mmHg (solid tumor). We assumed that for initial periods of peritoneal dialysis when osmotic pressure of dialysis fluid is high: 1) osmotic pressure gradient across the capillary wall prevails over the combined Starling forces, 2) spatial profile of osmotic agent concentration in tissue (interstitial fluid) can be approximated by exponential function with the penetration depth ΛS. The model yields an equation for L/L0 to be solved numerically, but an approximated closed formula also works well for typical dialysis conditions. Results The model predicts that swelling of peritoneal tissue depends on factors such as tissue stiffness, tissue width, solute penetration depth, and transport parameters for tissue and capillary wall, and on the forces that induce fluid transport: intraperitoneal pressure and the increment of osmolality of dialysis fluid over plasma osmolality. Examples of L/L0 yielded by the model - with use of glucose 1.36% dialysis fluid and for two levels of ip hydrostatic pressure (Pip) - are shown. In Figure, left panel, for L0 = 1 cm representing human abdominal muscle, and solute diffusional penetration ΛS=ΛD=0.055 cm, or lower, as due to diffusion against fluid flow, ΛS=ΛD/2=0.027 cm, is plotted versus the tissue stiffness; the dialysis fluid with glucose 1.36% is applied (osmolality increment of 60 mmol/L at the beginning of peritoneal dwell, Waniewski et al, 1996) and Pip is 15 mmHg. As stiffness of abdominal and bowel muscles may be expected around 300 mm Hg, swelling might be up to 15%; it decreases with lower ip hydrostatic and osmotic pressures. Hypothetical dialysis at Pip = 0 (isobaric with interstitial fluid) would reduce swelling by factor 2, see Figure, right panel. The depth of osmotic agent penetration into the tissue impacts tissue hydration and swelling, see Figure 1 for L/L0 with twice reduced ΛS. The model and its approximation by the closed formula provide practically the same outcomes for clinical peritoneal dialysis, see Figure 1, but some discrepancy between them may occur for thin tissue, as rat abdominal wall. The approximate formula for L/L0 works well if ΛS is much shorter than L0. Nevertheless, for high degree of swelling a nonlinear theory should be constructed. Conclusion In peritoneal dialysis, exposure of peritoneal tissue to hypertonic dialysis fluid at increased hydrostatic pressure contributes to overhydration and swelling (by 5-15% after fluid infusion) of the tissue. The extent by which this swelling may contribute to changes in peritoneal tissue structure and function warrants further studies.