Impaired Permeability Research Articles

Cerebral Pathology in Hepatolenticular Degeneration (Wilson Disease)

Introduction. Hepatolenticular degeneration (HLD), or Wilson disease, is one of the severe progressive hereditary disorders of the nervous system. A number of questions regarding its pathogenesis and pathology are the subject of in-depth research. The aim of the study was to examine cerebral pathology and determine the leading factors in its pathogenesis in the autopsy cases of HLD. Materials and methods. A postmortem study was carried out in 15 deceased patients (14–35 years old) with HLD. In all cases, clinical diagnosis was based on the characteristic signs of CNS and liver damage, presence of the Kayser–Fleischer corneal ring, and specific biochemical abnormalities in copper and protein metabolism. A set of histological, neurohistological, and histochemical staining methods was used, including the histochemical study of copper after the fixation of brain slices in rubeanic acid. Results. In all cases, severe microcirculatory changes were found in the brain, characteristic of the angiotoxic component of HLD, with impaired vessel permeability and the development of persistent edema and spongiform changes in brain tissue. Changes were more often found in the basal nuclei area, as well as in the white matter of the cerebral hemispheres, cerebellum, and pons. The cytotoxic component of HLD was evident in the same regions of the brain, represented by degenerative changes in astrocytes and neurons, often ending in their death. The most frequent form of pathology was the appearance of Alzheimer type II glia with ‘naked’ nuclei, and much less frequently, Alzheimer type I glia. The histochemical study showed deposits of copper granules in the endothelial cells of microvessels, Alzheimer type II glia, and neurons – predominantly in the globus pallidus and the caudate nucleus. Conclusion. A set of pathogenic factors plays an essential role in the pathogenesis of the brain damage in HLD: the toxic effect of copper on the brain, the damage to and impaired permeability of the blood-brain barrier, severe metabolic disturbances caused by liver failure, and brain hypoxia.

An Analytical Model to Predict the Effects of Suspended Solids in Injected Water on the Oil Displacement Efficiency during Waterflooding

Suspended solids in the injection water cause impairment of water injectivity during waterflooding operations. Suspended solids affect reservoir properties and decrease the permeability of reservoir rocks causing an increase of injection pressure and a decrease in water injectivity. Removal of all suspended solids from injection water is an expensive and economically unfeasible process. To minimize the effects of suspended solids to the formation, it is necessary to determine an impairment mechanism of suspended solids on oil displacement and, therefore, optimize the water treatment process. In this paper, an analytical model that describes the relationship between injection water quality and impairment mechanisms on oil displacement is presented. A formation impairment was calculated, introducing the parameter called impairment ratio, which represents the ratio between suspended solids and pore size distribution of reservoir rock. Based on the impairment ratio, decreases in porosity and permeability were calculated with changes in capillary pressure, relative permeability, and displacement efficiency. The model was tested for three different types of injection water. Results indicated the presence of formation impairment even with the smallest particles. Suspended solids had the greatest influence on porosity and permeability impairment. The model could be used as input for reservoir modelling studies for monitoring and controlling displacement efficiency during waterflooding as well as for planning and modification of water treatment units.

Homeostatic state of microglia in a rat model of chronic sleep restriction.

Chronic sleep restriction (CSR) negatively impacts brain functions. Whether microglia, the brain's resident immune cells, play any role is unknown. We studied microglia responses to CSR using a rat model featuring slowly rotating wheels (3 h on/1 h off), which was previously shown to induce both homeostatic and adaptive responses in sleep and attention. Adult male rats were sleep restricted for 27 or 99 h. Control rats were housed in locked wheels. After 27 and/or 99 h of CSR, the number of cells immunoreactive for the microglia marker ionized calcium-binding adaptor molecule-1 (Iba1) and the density of Iba1 immunoreactivity were increased in 4/10 brain regions involved in sleep/wake regulation and cognition, including the prelimbic cortex, central amygdala, perifornical lateral hypothalamic area, and dorsal raphe nucleus. CSR neither induced mitosis in microglia (assessed with bromodeoxyuridine) nor impaired blood-brain barrier permeability (assessed with Evans Blue). Microglia appeared ramified in all treatment groups and, when examined quantitatively in the prelimbic cortex, their morphology was not affected by CSR. After 27 h, but not 99 h, of CSR, mRNA levels of the anti-inflammatory cytokine interleukin-10 were increased in the frontal cortex. Pro-inflammatory cytokine mRNA levels (tumor necrosis factor-α, interleukin-1β, and interleukin-6) were unchanged. Furthermore, cortical microglia were not immunoreactive for several pro- and anti-inflammatory markers tested, but were immunoreactive for the purinergic P2Y12 receptor. These results suggest that microglia respond to CSR while remaining in a physiological state and may contribute to the previously reported homeostatic and adaptive responses to CSR.

CgCmk1 Activates CgRds2 To Resist Low-pH Stress in Candida glabrata.

In Candida glabrata, the transcription factor CgRds2 has been previously characterized as a regulator of glycerophospholipid metabolism, playing a crucial role in the response to osmotic stress. Here, we report that CgRds2 is also involved in the response to pH 2.0 stress. At pH 2.0, the deletion of CgRDS2 led to reduced cell growth and survival, by 33% and 57%, respectively, compared with those of the wild-type strain. These adverse phenotypes resulted from the downregulation of genes related to energy metabolism in the Cgrds2Δ strain at pH 2.0, which led to a 34% reduction of the intracellular ATP content and a 24% decrease in membrane permeability. In contrast, the overexpression of CgRDS2 rescued the growth defect of the Cgrds2Δ strain and increased cell survival at pH 2.0 by 17% compared with that of the wild-type strain, and this effect was accompanied by significant increases in ATP content and membrane permeability, by 42% and 19%, respectively. Furthermore, we found that the calcium/calmodulin-dependent protein kinase (CaMK) CgCmk1 physically interacts with the PAS domain of CgRds2, and CgCmk1 is required for CgRds2 activation and translocation from the cytoplasm to the nucleus under pH 2.0 stress. Moreover, CgCmk1 is critical for CgRds2 function in resistance to pH 2.0 stress, because cells of the Cgrds2-pas strain with a disrupted CgCmk1-CgRds2 interaction exhibited impaired energy metabolism and membrane permeability at pH 2.0. Therefore, our results indicate that CgCmk1 positively regulates CgRds2 and suggest that they promote resistance to low-pH stress by enhancing energy metabolism and membrane permeability in C. glabrataIMPORTANCE An acidic environment is the main problem in the production of organic acids in C. glabrata The present study reports that the calcium/calmodulin-dependent protein kinase CgCmk1 positively regulates CgRds2 to increase intracellular ATP content, membrane permeability, and resistance to low-pH stress. Hence, the transcription factor CgRds2 may be a potential target for improving the acid stress tolerance of C. glabrata during the fermentation of organic acids. The present study also establishes a new link between the calcium signaling pathway and energy metabolism.

Ascorbate exacerbates iron toxicity on intestinal barrier function against Salmonella infection

Ascorbic acid is often used to enhance iron absorption in nutritional interventions, but it produces pro-oxidant effects in the presence of iron. This study aimed to evaluate ascorbate’s role in iron toxicity on intestinal resistance against foodborne pathogens during iron supplementation/fortification. In polarized Caco-2 cell monolayers, compared to the iron-alone treatment, the iron-ascorbate co-treatment caused more than 2-fold increase in adhesion, invasion and translocation of Salmonella enterica serovar Typhimurium. According to 3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyltetrazolium bromide assay, lactate dehydrogenase release and transepithelial electrical resistance, the iron-ascorbate co-treatment resulted in reduced cell viability and increased impairment of cell membrane and paracellular permeability compared to the iron-alone treatment. Butylated hydroxytoluene protected cells against these prooxidant toxicities of ascorbate. Ascorbate completely restored iron-induced intracellular oxidant burst and depletion of cytosolic antioxidant reserve, according to dichlorodihydrofluorescein fluorescence and intracellular reduced glutathione levels. In Salmonella-infected C57BL/6 mice, iron-ascorbate co-supplementation resulted in greater loss of body weight and appetite, lower survival rate, shorter colon length, heavier intestinal microvilli damage, and more intestinal pathogen colonization and translocation than the iron-alone supplementation. Overall, ascorbate would exacerbate iron toxicity on intestinal resistance against Salmonella infection through pro-oxidant impairment of intestinal epithelial barrier from extracellular side and/or by facilitating intestinal pathogen colonization.

Maternal Vitamin D Deficiency Increases Intestinal Permeability and Programs Wnt/β-Catenin Pathway in BALB/C Mice.

Recent studies suggest that vitamin D deficiency is associated with intestinal dysfunctions, but the underlying mechanism remains unclear. This study aimed to investigate whether maternal vitamin D deficiency increases intestinal permeability in offspring and its related mechanism. Timed-pregnant mice were fed with either a standard chow diet (SC) or a vitamin D-deprived chow diet (VD-) 6 weeks prior to breeding and kept on the same diet until the end of gestation. All offspring were fed an SC for 3 weeks after weaning and then observed for effects associated with maternal vitamin D deficiency. Maternal vitamin D deficiency increased intestinal permeability in offspring, which corresponded with the decreased expression of the tight junction protein claudin-1. Maternal vitamin D deficiency also repressed the messenger RNA expression of wingless/integrated family member 3a (Wnt3a) and the protein expression of nuclear β-catenin. The decreased Wnt3a gene expression in male was concurrent with the changes in histone H4 acetylation at either promoter or coding regions. The activation of the Wnt/β-catenin pathway protected against the impairment of intestinal permeability induced by maternal vitamin D deficiency. Maternal vitamin D deficiency increased intestinal permeability and decreased tight junction protein expression in offspring. The suppression of the Wnt/β-catenin signaling pathway through histone modification might be involved in the underlying mechanism.

A novel method for quantifying the permeability of isolated small venules

BackgroundThe wall of venules is the primary site for the regulation of the transfer of water, ions and larges molecules in order to maintain tissue homeostasis. The impairment of venular permeability can cause tissue edema, followed by organ dysfunction. To date, although some methods are available to visualize the permeability of vessels, the quantification of the results remains elusive. Thus the aim of the present study was to develop a novel method to quantify the permeability of small isolated venules.MethodsMouse mesenteric venules (160–200 μm diameter at 8.0 mmHg of perfusion pressure) were isolated, cannulated in a vessel chamber and perfused with MOPS‐PSS (pH=7.4 at 37°C). The perfusion chamber contained two glass cannulas (inflow and outflow). A PE tubing of 15 mm in length with a rectangular window (2 × 7 mm) carved in the center is pre‐inserted onto the inflow pipette. After a venule was cannulated, the PE tubing was pushed forward (directed from inflow to the outflow pipette) to create a small sealed pool between the two cannulas (see the illustration). The chamber solution was then aspirated, the micro‐pool was washed and filled with 30 μl fresh MOPS‐PSS through the opened window. The inflow and outflow pressures were set at 8 cmH2O to maintain a constant intravascular pressure. The perfusion apparatus was then placed into a 37°C humidified incubator to equilibrate for 30 minutes. After equilibration, a one‐cmH2O pressure gradient was established by an increasing the inflow pressure and a decreasing the outflow pressure equally to create a constant intraluminal flow composed of MOPS‐PSS containing 5×10−4 M Evans blue dye (EBD). Thus, changes in permeability of venules could be assessed by determining the EBD in the pool solution using fluorescence (620/680 nm) spectrometry method. The final level of EBD in samples was determined using an EBD standard curve (0.08–20 μg/ml) and normalized to the internal surface area of venules.ResultsHistamine (2×10−5, 2×10−4 and 2×10−3 M) elicited a dose‐dependent increase in EBD permeability from 7.63 ± 0.79 to 21.70 ± 2.28 ng/mm2/min. The histamine‐induced release of EBD was continuous and reached a peak within 15 min, responses that were significantly reduced by triprolidine hydrochloride an H1 receptor inhibitor to 14.71± 2.07 ng/mm2/min. In addition, we have found that 5% erythrocytes lysate (ECL) and 2 μg/ml lipopolysaccharide (LPS) significantly enhanced EBD permeability.ConclusionsUsing this novel micro‐chamber technique, we were able to quantify histamine, ECL, and LPS‐induced increases in permeability of isolated venules, thus this method offers a valuable tool for pharmacokinetic research of permeability at the scale of microcirculation.Support or Funding InformationSupportNIH HL070653 (An Huang) and HL129797 (Dong Sun),Scientific Excellence Program 2019, at the University of Physical Education, Innovation and Technology Ministry, Hungary TUDFO/51757/2019‐ITM (Akos Koller).

Intraarticular inflammatory response of human osteoarthritic chondrocytes induced by bacterial DNA

Purpose: Osteoarthritis (OA) is now recognized as an inflammatory condition and certain immunopathological phenomena have been implicated in the disease. One of the contributory factors is impaired gut permeability and translocation of bacterial components to the joints through circulation. Discovery of bacterial DNA in synovial tissue supported this assumption but its role in OA pathophysiology has not yet been elucidated. We aim to investigate immunostimulatory effects of human osteoarthritic chondrocytes in response to bacterial DNA.

Antibacterial activity of Siparuna guianensis essential oil mediated by impairment of membrane permeability and replication of pathogenic bacteria

The increasing prevalence of resistance to conventional antibiotics in pathogenic bacteria has demanded faster development of novel sources of antibacterial agents. In this context, biological activities shown by natural compounds have received particular attention. One of the alleged backslashes for these alternative bactericidal tools is the current knowledge gap regarding their action mechanisms. Here, we evaluated the activity of essential oil extracted of Negramina, Siparuna guianensis, plants against pathogenic bacteria Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pyogenes. We evaluated cytotoxic effects on bacterial cells and the action mechanisms of the essential oil. The gas chromatography analysis revealed that β-Myrcene (39.68%), epicurzerenone (18.16%) and germacrenes D (14.34%) and B (2.93%) are the major components of the S. guianensis essential oil. Interestingly, the essential oil exhibited toxicity against all pathogenic bacteria without affecting the human monocytic THP-1 cell line. This antibacterial activity resulted from strong bacterial growth inhibition and deregulation of bacterial cell wall permeability with increased nucleotides and K+ ions leakage. Furthermore, our molecular docking predictions indicated high affinity between some essential oil major components Germacrene B and active sites of bacterial DNA and RNA polymerases, which indicates possible impairments on the pathogenic bacteria cell replication processes.

Estimating transition time from deep filtration of particles to external cake during produced water re-injection and disposal

Water production management from oil and gas fields is a big challenge for petroleum industry. Re-injection and disposal of produced water into subterranean formations/oil reservoirs is considered as an environmentally-friendly solution for managing massive water production in petroleum industry. Formation damage resulted from plugging by dispersed particles in the injected water is one of the main concerns in waterflood/disposal projects that causes rapid permeability impairment. Main mechanisms for permeability decline due to injection of low-quality water are deep filtration of dispersed particles into the porous rocks and external filter cake formation on the injection surface. In this article, an empirical correlation is developed for prediction of transition time from deep bed filtration to external cake formation based on available experimental data points from the literature. The proposed correlation includes measurable parameters such as solid particle size to pore size ratio (jamming ratio) and injection concentration of suspended particles which was ignored in previous studies. The proposed correlation is evaluated with water injection data of 15 wells with good agreement. The developed correlation can be used for design and planning of operations with solid in liquid dispersion including drilling fluid, low-quality water flooding, and waste water disposal into subterranean formations.

Permeability alteration by salt precipitation: numerical and experimental investigation using X-Ray Radiography

The injection of a gas phase through a water saturated porous medium can reduce the water saturation not only by displacement mechanisms but also by evaporation mechanisms. In the presence of brine, this process can induce salt crystallization and precipitation within the porous medium with a risk of permeability alteration. In the field of gas production and storage, the occurrence of such a phenomenon can have detrimental consequence on the well productivity or injectivity. In this work, we investigated experimentally and numerically the effect of dry gas injection on salt precipitation and permeability impairment. State of the art equipment designed for high throughput coreflood experimentation was used to capture the dynamic of salt migration using X-Ray radiography. A set of experiments have been conducted on a sample of Bentheimer sandstone (10mm in diameter and 20 mm in length) as well as a two layers composite sample with a significant permeability contrast. Experiments were conducted using Nitrogen and KBr brine with different boundary conditions (i.e. with and without capillary contact). Results showed that salt precipitation results from the interplay of different parameters, namely pressure gradient, brine salinity, capillary forces and vapor partial pressure. Experimental observations indicate that in the case of dry gas injection, salt systematically precipitates but permeability alteration is observed only if a capillary contact is maintained with the brine. We built a 2D flow model integrating two-phase Darcy flow, capillary forces, salt effect on vapor partial pressure, dissolved salt transport, as well as the different PVT equilibria needed to describe properly the systems. Once calibrated, the model showed good predictability of lab scale experiment and thus can be used for parametrical study and upscaled to the well bore scale.

Asphaltene deposition and permeability impairment in shale reservoirs during CO2 huff-n-puff EOR process

This study focuses on asphaltene deposition and permeability impairment in shale oil reservoirs during CO2 huff-n-puff process. Four different huff-n-puff cycles, two oil samples and five different injection pressures were applied in this study. The results showed that the asphaltene deposed the most in the first cycle. The permeability reduced by 30.2%, 50.25%, and 58.31% after the first, third, and seventh injection cycle, respectively. After seven cycles, the cumulative oil recovery without asphaltene deposition was about 21.5% higher than that with asphaltene deposition. The permeability impairment degree first increased and then decreased with the increase of injection pressure.

Tubular injury triggers podocyte dysfunction by β-catenin-driven release of MMP-7.

Proteinuric chronic kidney disease (CKD) remains a major health problem worldwide. While it is well established that the progression of primary glomerular disease induces tubulointerstitial lesions, how tubular injury triggers glomerular damage is poorly understood. We hypothesized that injured tubules secrete mediators that adversely affect glomerular health. To test this, we used conditional knockout mice with tubule-specific ablation of β-catenin (Ksp-β-cat-/-) and subjected them to chronic angiotensin II (Ang II) infusion or Adriamycin. Compared with control mice, Ksp-β-cat-/- mice were dramatically protected from proteinuria and glomerular damage. MMP-7, a downstream target of β-catenin, was upregulated in treated control mice, but this induction was blunted in the Ksp-β-cat-/- littermates. Incubation of isolated glomeruli with MMP-7 ex vivo led to nephrin depletion and impaired glomerular permeability. Furthermore, MMP-7 specifically and directly degraded nephrin in cultured glomeruli or cell-free systems, and this effect was dependent on its proteolytic activity. In vivo, expression or infusion of exogenous MMP-7 caused proteinuria, and genetic ablation of MMP-7 protected mice from Ang II-induced proteinuria and glomerular injury. Collectively, these results demonstrate that β-catenin-driven MMP-7 release from renal tubules promotes glomerular injury via direct degradation of the key slit diaphragm protein nephrin.

Soluble forms of adhesive molecules in blood serum as a marker of endothelial dysfunction in chronic generalized parodontitis.

An important factor in the pathogenesis of chronic inflammation in periodontitis is endothelial dysfunction (ED). Adhesion molecules are markers of impaired barrier function, adhesive properties and vascular permeability. The study of the concentration of soluble adhesion molecules is very promising in the diagnosis of ED. The purpose of this research was to study changes in the concentration of soluble forms of adhesive molecules of the selectin family and the immunoglobulin superfamily when used as markers of systemic manifestations of ED in the dynamics of the treatment of chronic generalized periodontitis (CP) using surgical and therapeutic schemes. 60 patients with CP (33 women and 27 men) and 20 clinically healthy volunteers (10 men and 10 women) were examined. The state of the endothelium was assessed by the content in the serum of soluble forms of adhesive molecules - sP- and sE-selectins, intercellular adhesive molecules of type 1 (sICAM-1), vascular molecules of cell adhesion of type 1 (VCAM-1) by ELISA. The short-term results of non-surgical treatment of CP are more effective in correction of vascular wall adhesive properties disorders compared with surgical treatment. Conservative treatment of chronic hepatitis C effectively adjusted the blood content of adherent endothelium molecules in women than in men. The long-term results of applying this scheme were characterized by partial preservation of a positive effect on the adhesive properties of the endothelium, however, long-term results were inferior to short-term ones. Surgical treatment of CP in women in the early postoperative period was accompanied by reactive impairment of the adhesive properties of the endothelium. The long-term results of this treatment regimen testified to its greater effectiveness. In women, the effectiveness of treatment of CP in restoring the adhesive properties of the endothelium was higher than in men. The results obtained allow us to conclude that the systemic manifestations of ED in CP were characterized by an increase in the concentration in the blood of soluble forms of adhesion molecules. The dynamics of the concentration of adhesive molecules during the treatment of СР testified to the dependence of the sex of patients on the effectiveness of the influence of therapeutic and surgical treatment regimens on the systemic manifestations of ED.

Numerical simulation of particulate suspension transport and permeability impairment in an actual rough fracture under normal stresses

AbstractThe transportation and capture of particulate suspension in a rough fracture are widely encountered in hydrocarbon exploitation. According to a full review of the literature, traditional studies mainly focus on the placement and settlement of coarse particles such as proppants and lost circulation materials. Furthermore, a fracture is often considered to be equivalent to smooth parallel plates, whereas actual fractures are roughly walled with microconvex and are affected by normal stresses. The particulate suspension transport mechanism in a fracture under different normal stresses is still unclear. This paper proposes an approach to evaluate the permeability impairment caused by size‐exclusion of solid particles in a fracture under different normal stresses. The morphology of fracture flow space under different normal stresses is obtained by using optical scanning and FEM. Furthermore, the unresolved CFD‐DEM method is used to study the mechanism of the capture and migration of the particulate suspension in a fracture. The simulation results are in agreement with the experimental results. Furthermore, the effects of the particle size, particle concentration, injected particle volume, fracture occurrence, and applied pressure on particle invasion are discussed.

Developing a methodology to characterize formation damage (pore plugging) due to fines migration in sand control tests

Stand-alone screens (SAS) have been widely used in steam assisted gravity drainage (SAGD) operations. Although many researchers investigated the flow performance of SAS through sand control tests, the formation damage (pore plugging) due to fines migration has not been characterized under multi-phase flow conditions. In this study, a methodology is developed to quantify and characterize the fines migration under multi-phase flow sand control testing conditions.A large-scale sand retention test (SRT) facility is used to investigate the flow performance of SAS. Duplicated sand samples with similar particle size distribution (PSD), shape, and mineralogy properties to the McMurray Formation oil sands are obtained by mixing different types of commercial sands, silts, and clays. Oil and brine are simultaneously injected into the sand-pack at different water-cut levels and liquid rates to emulate the changing inflow conditions in SAGD operations. The saturation levels in each flow stage are measured to determine the relative permeability values. Next, the relative permeability curves of the duplicated sand-pack sample are measured following the steady-state method. Finally, the pressure data obtained from the SRT in each flow stage are coupled with the relative permeability values to calculate the retained permeability as the indicator of flow performance of SAS'.Generally, testing results show that single-phase oil flow generates minor and negligible permeability impairments in the near-screen zone of the sand-pack. An evident permeability reduction is observed once the water breakthrough happens, indicating that the wetting-phase fluid significantly mobilizes fine particles and causes pore plugging. Also, with the increase of flow rate and water cut, a further reduction in permeability is found as a result of the higher drag force and greater exposure area of fines to brine.The proposed methodology presented in this study allows quantitative characterization of the formation damage under multi-phase flow condition and provides a practical and straightforward method for the evaluation of the SAS's flow performance.

PEDF Can Rescue the Inhibition of Injured Endothelial Cells on Hematopoietic Stem Cell Expansion Ex Vivo

Introduction: Endothelial cells (ECs) provide a fertile niche for hematopoietic stem cell (HSC) maintenance, differentiation, and migration.Several studies have indicated that bone marrow (BM) vascular niche was impaired after HSC transplantation and severely inhibited hematopoietic reconstruction. Pigment epithelium-derived factor (PEDF) is an important potential cytoprotection and therapeutic agent for injured cells. The direct role of the injured endothelial cells on hematopoietic stem cells and whether PEDF has protective effect in this system remain unknown. This study aims to observe the influence of enjured ECs on HSCs and to explore the role of PEDF in endothelial-HSC coculture system. Methods: Injury of Endothelial cells by two important preparative regimenconditioning radiation and Busulfan respectively was evaluated with CCK8 assay. The expression of endothelial tight junctions(TJs),adherent junctions related molecules and endothelial to Mesenchymal Transition molecules such as ZO-1, Occludin,VE-cadherin, ICAM, α-SMA, CD31 and VCAM were detected by RT-qPCR, flow cytometry, immunofluorescence and western blot. The effects of injured endothelial cells on HSC self-renewal, differentiation, cell cycle and apoptosis were evaluated by flow cytometry, photography, viable cell count and clone formation assay. Hematopoiesis regulation factors SCF, IL-6, TGF-β and TNF-α were detected by ELISA. The protective effect of PEDF was also explored. Results: Both radiation and Busulfan could decrease cell viability of endothelial cells. The expression level of ZO-1, Occludin, VE-cadherin, ICAM, CD31 and VCAM were decreased and α-SMA was increased when EC exposed to radiation or Busulfan suggesting endothelial activation, impaired EC permeability and endothelial to Mesenchymal Transition after EC injured. Compared with normal endothelial cells and hematopoietic stem cell co-culture group, the HSC% of injured endothelial cells and hematopoietic stem cells co-cultured group were significantly decreased, the cell colony formation ability was decreased, the proportion of mature cells increased, and the damage of endothelial cells could not maintain the characteristics of HSC, weakened the self-renewal and multidirectional differentiation potential of HSC and promoted the maturation of HSC. After the administration of PEDF, endothelial to Mesenchymal Transition of EC was suppressed and the EC permeability was improved. Most importantly, the proportion of HSC was significantly increased, and the proportion of mature cells decreased in the coculture system. Conclusion: Injured endothelial cells can inhibit proliferation of hematopoietic stem cells, self-renewal and promote HSC differentiation. PEDF could ameliorate endothelial injury and promote HSC expansion by suppressing endothelial-mesenchymal transition and protecting TJs and AJs. Disclosures No relevant conflicts of interest to declare.

Palmitic acid damages gut epithelium integrity and initiates inflammatory cytokine production

The mechanisms leading to the low-grade inflammation observed during obesity are not fully understood. Seeking the initiating events, we tested the hypothesis that the intestine could be damaged by repeated lipid supply and therefore participate in inflammation. In mice, 1–5 palm oil gavages increased intestinal permeability via decreased expression and mislocalization of junctional proteins at the cell–cell contacts; altered the intestinal bacterial species by decreasing the abundance of Akkermansia muciniphila, segmented filamentous bacteria, and Clostridium leptum; and increased inflammatory cytokine expression. This was further studied in human intestinal epithelial Caco-2/TC7 cells using the two main components of palm oil, i.e., palmitic and oleic acid. Saturated palmitic acid impaired paracellular permeability and junctional protein localization, and induced inflammatory cytokine expression in the cells, but unsaturated oleic acid did not. Inhibiting de novo ceramide synthesis prevented part of these effects. Altogether, our data show that short exposure to palm oil or palmitic acid induces intestinal dysfunctions targeting barrier integrity and inflammation. Excessive palm oil consumption could be an early player in the gut alterations observed in metabolic diseases.

Intestinal permeability in the pathogenesis of liver damage: From non-alcoholic fatty liver disease to liver transplantation.

The intimate connection and the strict mutual cooperation between the gut and the liver realizes a functional entity called gut-liver axis. The integrity of intestinal barrier is crucial for the maintenance of liver homeostasis. In this mutual relationship, the liver acts as a second firewall towards potentially harmful substances translocated from the gut, and is, in turn, is implicated in the regulation of the barrier. Increasing evidence has highlighted the relevance of increased intestinal permeability and consequent bacterial translocation in the development of liver damage. In particular, in patients with non-alcoholic fatty liver disease recent hypotheses are considering intestinal permeability impairment, diet and gut dysbiosis as the primary pathogenic trigger. In advanced liver disease, intestinal permeability is enhanced by portal hypertension. The clinical consequence is an increased bacterial translocation that further worsens liver damage. Furthermore, this pathogenic mechanism is implicated in most of liver cirrhosis complications, such as spontaneous bacterial peritonitis, hepatorenal syndrome, portal vein thrombosis, hepatic encephalopathy, and hepatocellular carcinoma. After liver transplantation, the decrease in portal pressure should determine beneficial effects on the gut-liver axis, although are incompletely understood data on the modifications of the intestinal permeability and gut microbiota composition are still lacking. How the modulation of the intestinal permeability could prevent the initiation and progression of liver disease is still an uncovered area, which deserves further attention.

053 Myosin heavy chain, a novel allergen for fish allergy in patients with atopic dermatitis

The frequency of fish allergy (FA) has been increasing since seafood cuisine such as raw fish has become popular. FA is caused by many allergens, among which parvalbumin was most frequently documented; however, little is known about other allergens in a real-world setting. In this study we explored IgE-reactivity with fish allergens using FA patients’ serum. Western blot analysis revealed that a newly found protein of approximately 250kD was recognized by serum IgE in five out of six FA patients but not in control individuals. The protein of interest separated on the two-dimensional gel electrophoresis was identified as myosin heavy chain (MYHC) by LS-MS/MS. The IgE immunoreactivity was reproduced when used newly synthesized recombinant MYHC. The patients’ serum IgE, which had been pre-absorbed with fish extracts, lost the reactivity to MYHC recombinant protein, strongly suggesting the antigen specificity for MYHC. Finally, the basophil activation test revealed rsMYHC- dependent IgE reactivity as well as pathogenetic relevance. Results from the present study implicated that FA patients were heterogenous in their allergen specificities since some showed positive for parvalbumin but not for MYHC, and the others showed vice versa. All the FA patients with MYHC-specific IgE had atopic dermatitis at present or in the past. Therefore, impaired permeability barrier might have contributed to the sensitization of this high molecular allergen, MYHC, after touching fish by bear hands. Because raw fish cuisine is popular not only in Japan but also outside of Japan, the risk of FA may be increasing.