Hepatic Sinusoids Research Articles

Retrorsine Cooperates with Gut Microbiota to Promote Hepatic Sinusoidal Obstruction Syndrome by Disrupting the Gut Barrier

Hepatic sinusoidal obstruction syndrome (HSOS) is a life-threatening syndrome, and a cause is exposure to pyrrolizidine alkaloid (PA)-containing products. It is well-established that retrorsine (RTS), a representative Pas, insults hepatic sinusoidal endothelial cells and ensues congestion of hepatic sinusoids. However, little known about the impact of Pas on gut microbiota and intestinal barrier and inflammation in HSOS. Mice were gavaged with or without nonabsorbable antibiotics (ABX), followed by a single dose of RTS. The gut microbiota was examined by 16S rDNA sequencing. ABX pretreatment significantly reversed RTS-induced liver damage. RTS altered gut microbiota composition, increasing Gram-negative bacteria and resulting in a sharp elevation of circulating lipopolysaccharides (LPS) in HSOS mice. Gut decontamination with ABX alleviated RTS-induced intestine inflammation, protected against disruption of the intestinal epithelial barrier and gut vascular barrier (GVB), and suppressed hepatic LPS-NF-κB pathway activation in RTS-induced HSOS. Importantly, the LPS level was positively correlated with MELD score in patients with HSOS. Elevated LPS in patients with HSOS confirmed that Gram-negative bacteria were involved in the pathogenesis of HSOS. RTS, a PA, cooperated with gut dysbiosis to cause intestinal inflammation and gut barrier compromise that increased transport of gut-derived LPS into the liver through the portal vein, which contributed to the pathology of HSOS. Modulating the gut microbiota, protecting the intestinal barrier, and suppressing intestinal inflammation with prebiotics or antibiotics might be a useful pharmacologic intervention in HSOS.

JAM-A is a multifaceted regulator in hepatic fibrogenesis, supporting LSEC integrity and stellate cell quiescence.

Leukocyte infiltration is a hallmark of hepatic inflammation. The Junctional Adhesion Molecule A (JAM-A) is a crucial regulator of leukocyte extravasation and is upregulated in human viral fibrosis. Reduced shear stress within hepatic sinusoids and the specific phenotype of liver sinusoidal endothelial cells (LSEC) cumulate in differing adhesion characteristics during liver fibrosis. The aim of this study was to define the functional role of cell-specific adhesion molecule JAM-A during hepatic fibrogenesis. Complete, conditional (intestinal epithelial; endothelial) and bone marrow chimeric Jam-a knockout animals and corresponding C57Bl/6 wild-type animals were treated with carbon tetrachloride (CCl4 , 6weeks). For functional analyses of JAM-A, comprehensive in vivo studies, co-culture models and flow-based adhesion assays were performed. Complete and bone marrow-derived Jam-a-/- animals showed aggravated fibrosis with increased non-sinusoidal, perivascular accumulation of CD11b+ F4/80+ monocyte-derived macrophages in contrast to wild-type mice. Despite being associated with disturbed epithelial barrier function, an intestinal epithelial Jam-a knockout did not affect fibrogenesis. In endothelial-specific Jam-a-/- animals, liver fibrosis was aggravated alongside sinusoid capillarization and hepatic stellate cell (HSC) activation. HSC activation is induced via Jam-a-/- LSEC-derived secretion of soluble factors. Sinusoid CD31 expression and hedgehog gene signalling were increased, but leukocyte infiltration and adhesion to LSECs remained unaffected. Our models decipher cell-specific JAM-A to exert crucial functions during hepatic fibrogenesis. JAM-A on bone marrow-derived cells regulates non-sinusoidal vascular immune cell recruitment, while endothelial JAM-A controls liver sinusoid capillarization and HSC quiescence.

Reduction of Stabilin-2 Contributes to a Protection Against Atherosclerosis.

We have previously identified a novel atherosclerosis quantitative trait locus (QTL), Arch atherosclerosis 5 (Aath5), on mouse chromosome 10 by three-way QTL analyses between Apoe−/− mice on a DBA/2J, 129S6 and C57BL/6J background. The DBA/2J haplotype at the Aath5 locus was associated with smaller plaque size. One of the candidate genes underlying Aath5 was Stabilin-2 (Stab2), which encodes a clearance receptor for hyaluronan (HA) predominantly expressed in liver sinusoidal endothelial cells (LSECs). However, the role of Stab2 in atherosclerosis is unknown. A congenic line of Apoe−/− mice carrying Aath5 covering the Stab2DBA allele on a background of 129S6 confirmed the small reductions of atherosclerotic plaque development. To further determine whether Stab2 is an underlying gene for Aath5, we generated Stab2−/−Apoe−/− mice on a C57BL/6J background. When fed with a Western diet for 8 weeks, Stab2−/−Apoe−/− males developed approximately 30% smaller plaques than Stab2+/+Apoe−/− mice. HA was accumulated in circulation but not in major organs in the Stab2 deficient mice. STAB2-binding molecules that are involved in atherosclerosis, including acLDL, apoptotic cells, heparin and vWF were not likely the direct cause of the protection in the Stab2−/−Apoe−/− males. These data indicate that reduction of Stab2 is protective against atherosclerotic plaque development, and that Stab2 is a contributing gene underlying Aath5, although its effect is small. To test whether non-synonymous amino acid changes unique to DBA/2J affect the function of STAB2 protein, we made HEK293 cell lines expressing STAB2129 or STAB2DBA proteins, as well as STAB2129 proteins carrying each of five DBA-unique replacements that have been predicted to be deleterious. These mutant cells were capable of internalizing 125I -HA and DiI-acLDL similarly to the control cells. These results indicate that the amino acid changes unique to DBA/2J are not affecting the function of STAB2 protein, and support our previous observation that the reduced transcription of Stab2 in the liver sinusoid as a consequence of the insertion of a viral-derived sequence, intracisternal A particle, is the primary contributor to the athero-protection conferred by the DBA/2J allele.

Gynura segetum-induced liver injury leading to acute liver failure: a case report and literature review

BackgroundGynura segetum (GS) is widely used in medical care and in community settings in China as the herbal remedy. It is widely thought to have antiphlogistic properties and pain relief in traditional Chinese medicine. It has been reported that GS can cause chronic drug-induced liver injury (DILI), manifested as hepatic sinusoid obstruction syndrome (HOSO). But case reports of acute DILI developing acute liver failure (ALF) due to GS are extremely rare.Case presentationWe report a case of a 63-year-old female patient with hepatolithiasis for more than 6 years. There were no deterioration of liver function and no history of viral liver disease, autoimmune liver disease, blood transfusion or surgical allergy before operation. ALF and grade II liver encephalopathy occurred after partial hepatectomy. To follow up the medical history, the patient has been taking GS (Tusanqi) for a year and a half. The causality assessment was done by the updated Roussel Uclaf Causality Assessment Method, and the possibility of DILI caused by GS as highly probable for the score was 6 points. Excluding other causes, a diagnosis of DILI-associated ALF was established. After symptomatic support and artificial liver support system (ALSS) treatment, the clinical symptoms and signs of the patients were significantly improved. After discharge, the liver function of the patients returned to normal.ConclusionsBased on this rare case of severe liver injury, we recommend that timely prevention, identification, and appropriate management of DILI is essential for patients with a history of taking GS and other hepatotoxic drugs, and careful monitoring of liver function for patients with DILI could avoid ALF as far as possible.

Liver Environment-Imposed Constraints Diversify Movement Strategies of Liver-Localized CD8 T Cells.

Pathogen-specific CD8 T cells face the problem of finding rare cells that present their cognate Ag either in the lymph node or in infected tissue. Although quantitative details of T cell movement strategies in some tissues such as lymph nodes or skin have been relatively well characterized, we still lack quantitative understanding of T cell movement in many other important tissues, such as the spleen, lung, liver, and gut. We developed a protocol to generate stable numbers of liver-located CD8 T cells, used intravital microscopy to record movement patterns of CD8 T cells in livers of live mice, and analyzed these and previously published data using well-established statistical and computational methods. We show that, in most of our experiments, Plasmodium-specific liver-localized CD8 T cells perform correlated random walks characterized by transiently superdiffusive displacement with persistence times of 10-15 min that exceed those observed for T cells in lymph nodes. Liver-localized CD8 T cells typically crawl on the luminal side of liver sinusoids (i.e., are in the blood); simulating T cell movement in digital structures derived from the liver sinusoids illustrates that liver structure alone is sufficient to explain the relatively long superdiffusive displacement of T cells. In experiments when CD8 T cells in the liver poorly attach to the sinusoids (e.g., 1 wk after immunization with radiation-attenuated Plasmodium sporozoites), T cells also undergo Lévy flights: large displacements occurring due to cells detaching from the endothelium, floating with the blood flow, and reattaching at another location. Our analysis thus provides quantitative details of movement patterns of liver-localized CD8 T cells and illustrates how structural and physiological details of the tissue may impact T cell movement patterns.

Cytokine-Induced JAK2-STAT3 Activates Tissue Regeneration under Systemic or Local Inflammation.

We investigated the immune response mechanisms under systemic and local inflammation using mouse models whereby lipopolysaccharide (LPS) was administered intraperitoneally to induce systemic inflammation, and epicutaneous sensitization with ovalbumin was used to induce local inflammation. LPS increased the immune cell infiltration in the cardiac muscle near the aorta, alveoli, hepatic sinusoid, renal interstitium, and the submucosal layer of the duodenum. Similarly, ovalbumin increased the abundance of macrophages in the skin. Both LPS and ovalbumin induced NF-κB p65 and IκBα phosphorylation, as well as the expression of NF-κB target genes (TLR4, IL6, and TNFα). Additionally, both LPS and ovalbumin led to an increase in the absolute IL-1β, IL-6, and TNFα serum levels and cytokine-related janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) phosphorylation. Moreover, the activated JAK2/STAT3 signaling increased the number of Ki67-positive cells (proliferating cells) and development pathway target gene expression (regeneration) in the inflammation models. In conclusion, LPS and ovalbumin increase immune cell infiltration in tissues, NF-κB activation, cytokine levels in serum, cytokine-stimulated JAK2/STAT3 signaling, and tissue regeneration.

Fumonisin B1 induces hepatotoxicity in mice through the activation of oxidative stress, apoptosis and fibrosis

Fumonisin B1 (FB1) is a harmful environmental pollutant that induces hepatotoxicity, but the mechanism is still poorly understood. Therefore, the aim of this work was to investigate the effects of FB1 on the liver of mice and discover the underlying molecular mechanisms. A total of 40 male mice were exposed to 0 or 5 mg/kg FB1 for 42 days, and then, they were sacrificed, and the liver and blood were collected. Besides, AML12 cells were exposed to FB1. Biochemical and liver related indexes as well morphological changes, redox, apoptosis and fibrosis related markers were measured in liver and AML12 cells. The results showed that the liver function and biochemical indexes in the blood were changes, and the histopathological analysis indicated that FB1 exposure caused hepatic sinusoid atrophy, hemosiderosis, hepatocyte steatosis and fibrosis, finally inducing liver injury. Notably, a significant increase in the intracellular antioxidant enzymes SOD1, SOD2, NF-κB (p65), H2O2 and NO was found in FB1 exposed AML12 cells and liver tissues. In addition, TUNEL staining showed many apoptotic cells, and western blotting revealed a significant increase in the pro-apoptosis proteins. FB1 also induced liver fibrosis by triggering TGF-β1/α-SMA/collagen/MMP signaling in the hepatocytes. Our results provide a novel explanation of the toxicological mechanism of action of FB1, which provoked oxidative stress, apoptosis and fibrosis in mice liver.

A strategy of vascular‐targeted therapy for liver fibrosis

Background and AimsNo effective treatments are available for liver fibrosis. Angiogenesis is deeply involved in liver fibrogenesis. However, current controversial results suggest it is difficult to treat liver fibrosis through vascular targeting. There are three different microvessels in liver: portal vessels, liver sinusoids, and central vessels. The changes and roles for each of the three different vessels during liver fibrogenesis are unclear. We propose that they play different roles during liver fibrogenesis, and a single vascular endothelial cell (EC) regulator is not enough to fully regulate these three vessels to treat liver fibrosis. Therefore, a combined regulation of multiple different EC regulatory signaling pathway may provide new strategies for the liver fibrosis therapy. Herein, we present a proof‐of‐concept strategy by combining the regulation of leukocyte cell‐derived chemotaxin 2 (LECT2)/tyrosine kinase with immunoglobulin‐like and epidermal growth factor–like domains 1 signaling with that of vascular endothelial growth factor (VEGF)/recombinant VEGF (rVEGF) signaling.Approach and ResultsThe CCl4‐induced mouse liver fibrosis model and NASH model were both used. During fibrogenesis, vascular changes occurred at very early stage, and different liver vessels showed different changes and played different roles: decreased portal vessels, increased sinusoid capillarization and the increased central vessels the increase of portal vessels alleviates liver fibrosis, the increase of central vessels aggravates liver fibrosis, and the increase of sinusoid capillarization aggravates liver fibrosis. The combinational treatment of adeno‐associated viral vector serotype 9 (AAV9)–LECT2–short hairpin RNA (shRNA) and rVEGF showed improved therapeutic effects, but it led to serious side effects. The combination of AAV9‐LECT2‐shRNA and bevacizumab showed both improved therapeutic effects and decreased side effects.ConclusionsLiver vascular changes occurred at very early stage of fibrogenesis. Different vessels play different roles in liver fibrosis. The combinational treatment of AAV9‐LECT2‐shRNA and bevacizumab could significantly improve the therapeutic effects on liver fibrosis.

A simple fluorescent strategy for liver capillary labeling with carbon quantum dot-lectin nanoprobe.

Taking the hepatic sinusoid (HS) as the main delivery area of liver nutrients and metabolic waste, recognizing its structure is important for a deep understanding of liver function. In this paper, based on lycopersicon esculentum lectin (LEL), with targeting ability for endothelial cells, and carbon quantum dots (CQDs), with high biosafety, an LEL-coupled CQD immunofluorescence probe (CQD@LEL) that can label microvessels is designed and used for the fluorescence labeling and imaging of HS in liver tissue sections. The CQD size is approximately 2 nm. Blue fluorescence is emitted under excitation; its optimal excitation wavelength is 400 nm while the emission is at about 450 nm. Gel electrophoresis and capillary electrophoresis confirm that glutaraldehyde can couple LEL to CQD, and the obtained CQD@LEL retains the fluorescence property and has good stability. Optimization experiments show that its labeling effect is positively correlated with time and probe concentration for dyeing the blood vessels of mouse liver slices. In order to improve the effect further, a probe concentration of 0.17 mg mL-1 and incubation time of 3 h were chosen to label the liver tissue sections. The results show that the liver microvessels are formed by interstitial structures among the hepatic cords, and the HS presents a granular or patchy appearance. H&E and ultrathin section TEM show that the microvascular wall of the liver is composed of discontinuous endothelial cells, and there are Kupffer cells and other cells in the tubes, proving that our probe can clearly label the structure and morphology of liver microvessels. This work is of great significance for the visualization of HS.

Pathology of offbeat lesions in an outbreak of systemic histomoniasis in desi chickens

An outbreak of multisystemic histomoniasis in six weeks-old desi chickens from a rural based poultry farm holding 500 birds for commercial purpose associated with unusual visceral lesions and high mortality is reported. Birds were reported to have clinical signs of depression, loss of production, yellowish diarrhoea and high mortality. Cumulative mortality of the affected flock was reported to be 60% within a period of 7-10 days. Postmortem examination of the dead birds revealed enlargement of liver covered with pale whitish viscous membranous layer. Hepatic parenchyma showed multifocal, pale whitish to yellow, circular, press button like necrotic lesions varying from 0.3 to 0.5 cm diameter. Few of these lesions were coalescing and appeared as lesions of lymphoma. Spleen was slightly enlarged and congested. Bursa of Fabricius was distended and contained well organised, creamy white, firm mass exhibiting casting of bursal plicae. Kidney revealed multifocal greyish white foci (3-5 mm). Caecum showed moderate longitudinal corrugation of the mucosa. Microscopically, liver showed multifocal necrotic hepatitis with numerous scattered degenerative forms of histomonads surrounded by clear halo, having bull’s eye appearance within the necrotic areas. Mature trophozoites of invasive form of histomonads were also found in the hepatic sinusoids. Bursa of Fabricius revealed severe subacute to chronic cloacal bursitis associated with presence of histomonads within the follicle. Bursal follicles revealed severe lymphoid depletion and cystic degeneration. Multifocal myocarditis, pancreatitis, pneumonia and neuronal degeneration with satellitosis were the other associated lesions observed. Periodic-acid Schiff stained tissue sections revealed intense purple magenta-coloured degenerative forms of histomonads within the necrotic areas of liver, bursa of Fabricius and caecum. This report records the outbreak of naturally occurring multisystemic histomoniasis in layer-type desi chicken associated with unusual lesions including cloacal bursitis, myocarditis, pancreatitis and pneumonia. The present study also validates the earlier postulates of immunosuppression induced primarily by histomoniasis causing severe lymphoid depletion in bursa of Fabricius.

Anatomical, Histological, and Ultrasonographical Studies on the Liver of Red Fox (Vulpes vulpes) with its Arterial Blood Distribution and Biliary Ducts

The study aimed to investigate the anatomical and histological characteristics of the Egyptian red fox. We performed liver ultrasonography on eight animals while used two livers for morphological study. To illustrate the hepatic artery branches, two specimens were injected with colored red latex neoprene through the abdominal aorta. The other two specimens were injected with a mixture of lead oxide and colored green latex neoprene through the major duodenal papilla to demonstrate the radiological images of the biliary duct pattern. The last two specimens were used for histological study. The fox's liver had six lobes; left lateral, left medial, quadrate, right medial, right lateral, and caudate lobes. The gall bladder was pear-shaped and was embedded in a fossa between the right medial and the quadrate lobes. The left hepatic duct formed the common bile duct, and the cystic duct union then passed about 0.5-1cm to join with the right hepatic duct. The branches of the proper hepatic artery supply the liver lobes. Histologically, liver parenchyma consisted of lobules; each lobule had a central vein and hepatic cords with hepatic sinusoids in between. Histochemically, hepatocytes were stained with Periodic Acid Schiff and Bests carmine stains. Gall bladder lined by simple columnar cells rests on fibrous propria-submucosa rich in blood capillaries. This study has practical importance in surgical treatment, as in partial hepatic lobectomy and hepatic artery or lobar arteries ligation in case of tumors.

Blood Supply and Oxygenation Status of the Liver: From Physiology to Malignancy.

To maintain a multitude of vital functions, blood flow to the normal liver and the hepatic oxygenation status has to be kept on a high level (1.0-1.2mL/g/min and 30-40mmHg, respectively). There is a longitudinal oxygen partial pressure (pO2) gradient within the liver sinusoids between periportal inflow and outflow into the central vein leading to a zonation of the O2 status, which is associated with a zoning of liver functions. Oxygenation of metastatic lesions of colorectal cancers in the liver is poor due to a dysfunctional vascularity and inadequate blood supply. Hepatocellular carcinomas (HCCs) are highly vascularised (arterialised), metabolically very active and present with a predominantly arterial blood supply. HCCs are generally believed to be very hypoxic. However,confirmation of severe hypoxia based on reliable, direct pO2 measurements in HCCs is still missing.

Mesoscale visualization of three-dimensional microvascular architecture and immunocyte distribution in intact mouse liver lobes.

Rational: The complex vascular architecture and diverse immune cells of the liver are critical for maintaining liver homeostasis. However, quantification of the network of liver vasculature and immunocytes at different scales from a single hepatic lobule to an intact liver lobe remains challenging.Methods: Here, we developed a fast and fluorescence-preserving transparency method, denoted liver-CUBIC, for systematic and integrated analysis of the microcirculation and the three-dimensional distribution of dendritic cells (DCs)/macrophages in intact liver lobes.Results: Whole-mount imaging at mesoscale revealed that the hepatic classical lobule preferred the oblate ellipsoid morphology in the mouse liver and exhibited hepatic sinusoids with heterogeneous arrangement and intricate loop structure. Liver fibrosis not only induces sinusoidal density increase but also promotes sinusoidal arrangement with increased sinusoidal branch and loop structure. Meanwhile, we found that CD11c+ DCs followed a lognormal distribution in the hepatic lobules, skewing toward lobular boundary in steady state. CCl4-induced chronic liver injury promoted CD11c+ DC rearrangement at the lobular border before the formation of liver fibrosis. Furthermore, through whole-mount imaging of tumor-immune cell-vascular crosstalk in intact lobes based on liver-CUBIC, we characterized an accumulation of CX3CR1+CCR2+F4/80+ macrophages at metastatic foci in early colorectal liver metastases. Importantly, colorectal cells secrete CCL2 to mobilize CX3CR1+CCR2+F4/80+ macrophages to accumulate at liver micrometastases, and the interruption of CCL2-induced macrophage accumulation inhibits early colonization of metastasis in the liver.Conclusions: Our investigation of the sinusoidal network and DC/macrophage arrangements through the liver-CUBIC approach and whole-mount imaging provide a powerful platform for understanding hepatic circulatory properties and immune surveillance in the liver.

Protective Effect of Nigella sativa and Onion Extract against 5-Fluorouracil-Induced Hepatic Toxicity

Aim: The present study intended to compare the antioxidant, anti-lipid peroxidation, and anti-inflammatory potentials of Nigella Sativa (NS) and onion extract on 5-FU-induced liver damage in rats. Material and methods: 48 rats were divided into control, control group of the onion extract, control group of the NS extract, 5-FU-treated, concomitant NS-treated, and concomitant onion extract-treated. Liver sections were processed for histological analysis (light and electron microscopic examination). Liver enzymes (ALT, AST, and ALP), inflammatory markers (TNF-α and IL-1), antioxidant markers (SOD, GSH, and GSH/GSSG ratio), 4-HNE, NF-κB, and Nrf2 were evaluated. Results: The 5-FU-treated group exhibited inflammation, congested hepatic sinusoid, and steatosis. Improvement with few pathological residues was seen in the concomitant extract-treated groups. The 5-FU-treated group showed higher liver enzymes. The enzymes decreased in the concomitantly treated groups. 5-FU induced liver damage through oxidative stress, inflammation, and lipid peroxidation. Concomitantly using NS and onion extracts resulted in a reduction in oxidative stress, lipid peroxidation, and inflammation. Conclusion: NS and onion extracts attenuated 5-FU-induced liver damage via antioxidative, anti-lipid peroxidative, and anti-inflammatory mechanisms. NS’s role was exceptional when compared with onion extract.

Telmisartan relieves liver fibrosis and portal hypertension by improving vascular remodeling and sinusoidal dysfunction

BackgroundsTelmisartan(TEL) has demonstrated anti-fibrotic and blood pressure lowering effect in various diseases. In this study, we aimed to explore the beneficial effects of TEL on portal hypertension(PHT). MethodsTwo models of cirrhosis-induced PHT were involved including carbon tetrachloride injection(CCl4) and bile duct ligation(BDL). Rats were orally gavaged with TEL for 4 weeks. After that, the portal pressure(PP) was determined, and liver and mesenteric tissue specimens were collected to evaluate inflammatory response, liver fibrosis, vascular remodeling, angiogenesis, etc. ResultsIn CCl4 PHT models, TEL decreased PP significantly from 12.79 ± 2.92 to 6.91 ± 1.19 mmHg(p < 0.05). In inflammatory response, hepatic expressions of interleukin(IL)-6, lipopolysaccharide(LPS), and tumor necrosis factor-α(TNF-α) were significantly decreased after TEL treatment. Moreover, in the liver fibrotic area, the expressions of α-smooth muscle actin(α-SMA), collagen1a1(Col1a1), desmin, transforming growth factor-β(TGF-β), and hydroxyproline, and serum hyaluronic acid were significantly decreased after TEL treatment. Additionally, the expressions of von Willebrand factor(vWF), vascular endothelial growth factor(VEGF) and platelet-derived growth factor-β(PDGF-β), matrix metallopeptidase(MMP)-2, and MMP-9 were ameliorated in liver sinusoid, while the expressions of MMP-2 and vWF were reduced in mesenteric arteries after TEL treatment. Meanwhile, TEL treatment up-regulated the hepatic expressions of an anti-fibrotic factor Krüppel-like factor-4(KLF-4) and its downstream endothelial nitric oxide synthase(eNOS) in rats with PHT. The performance of TEL in BDL model was similar but slightly weaker. ConclusionsTEL ameliorated the cirrhosis-induced PHT by reducing liver fibrosis, inflammation responses, angiogenesis, and vascular remodeling. Collectively, KLF-4 and eNOS were the possible molecular targets for the management of cirrhosis-associated PHT.

Effect of Ageratina adenophora on hepatic and pulmonic pathological lesions in horses.

The effect of Ageratina adenophora on pathological characteristics of the liver and lungs as well as serum biochemical parameters in horses were investigated. Ten horses without ingestion history of Ageratina adenophora were classified into the control group, and 10 poisoned but survived horses with 3 months ingestion history were set as the case group. Results showed that serum AST, ALT, ALP, magnesium and phosphorus were elevated significantly, while creatinine was decreased remarkably. Hematoxylin and eosin staining of liver tissues showed diffuse swelling or destruction of hepatocytes, narrowing or atrophy of the hepatic sinusoids, and little lymphocytic infiltration; lung tissues presented destroyed alveoli and inflammatory cell infiltration.

A Synthetic Analog of Resveratrol Inhibits the Proangiogenic Response of Liver Sinusoidal Cells during Hepatic Metastasis.

We utilized Fas21, a resveratrol analog, to modulate the function of hepatic stellate cells (HSCs) and liver sinusoidal endothelial cells (LSECs) during the angiogenic phase of murine liver metastasis by B16 melanoma and 51b colorectal carcinoma. Preangiogenic micrometastases were treated with Fas21 (1 mg/kg/day) or vehicle during the development of intra-angiogenic tracts. Mice treated with Fas21 showed reduced liver tumor foci in both liver metastasis models. Micrometastases were classified immunohistochemically, as well as according to their position coordinates and connection to local microvasculature. The volume of liver occupied by sinusoidal-type foci, containing infiltrating angiogenic capillaries, decreased by ~50% in Fas21-treated mice compared to vehicle-treated ones in both tumor metastasis models. The volume of portal foci, containing peripheral neoangiogenesis within a discontinuous layer of myofibroblasts, was similar in all experimental groups in both tumor metastasis models, but displayed enhanced necrotic central areas devoid of angiogenesis following Fas21 treatment. As a result, sinusoidal tumors from mice treated with Fas21 showed a 50% reduction in desmin(+)/asma(+) HSCs and CD31(+) vessel density, and a 45% reduction in intrametastatic VEGF mRNA compared with sinusoidal tumors from vehicle-treated mice. Necrotic portal metastases increased 2-4-fold in treated mice. In vitro, Fas21 reduced VEGF secretion by HSCs and 51b cells dose-dependently. Additionally, HSCs migration in response to tumor soluble factors was dose-dependently diminished by Fas21, as was LSEC migration in response to HSCs and tumor soluble factors. Resveratrol analog Fas21 inhibits the proangiogenic response of HSCs and LSECs during the development of murine liver metastasis.

Shear stress-induced cellular senescence blunts liver regeneration through Notch-sirtuin 1-P21/P16 axis.

The mechanisms involved in liver regeneration after partial hepatectomy (pHx) are complicated. Cellular senescence, once linked to aging, plays a pivotal role in wound repair. However, the regulatory effects of cellular senescence on liver regeneration have not been fully elucidated. Mice subjected to pHx were analyzed 14 days after surgery. The incomplete remodeling of liver sinusoids affected shear stress-induced endothelial nitric oxide synthase (eNOS) signaling on day 14, resulting in the accumulation of senescent LSECs. Removing macrophages to augment LSEC senescence led to a malfunction of the regenerating liver. A dynamic fluctuation in Notch activity accompanied senescent LSEC accumulation during liver regeneration. Endothelial Notch activation by using Cdh5-CreERT NICeCA mice triggered LSEC senescence and senescence-associated secretory phenotype, which disrupted liver regeneration. Blocking the Notch by γ-secretase inhibitor (GSI) diminished senescence and promoted LSEC expansion. Mechanically, Notch-hairy and enhancer of split 1 signaling inhibited sirtuin 1 (Sirt1) transcription by binding to its promoter region. Activation of Sirt1 by SRT1720 neutralized the up-regulation of P53, P21, and P16 caused by Notch activation and eliminated Notch-driven LSEC senescence. Finally, Sirt1 activator promoted liver regeneration by abrogating LSEC senescence and improving sinusoid remodeling. Shear stress-induced LSEC senescence driven by Notch interferes with liver regeneration after pHx. Sirt1 inhibition accelerates liver regeneration by abrogating Notch-driven senescence, providing a potential opportunity to target senescent cells and facilitate liver repair after injury.

Immunoreactivity of the SARS-CoV-2 entry proteins ACE-2 and TMPRSS-2 in murine models of hormonal manipulation, ageing, and cardiac injury

Previous work indicates that SARS-CoV-2 virus entry proteins angiotensin-converting enzyme 2 (ACE-2) and the cell surface transmembrane protease serine 2 (TMPRSS-2) are regulated by sex hormones. However, clinical studies addressing this association have yielded conflicting results. We sought to analyze the impact of sex hormones, age, and cardiovascular disease on ACE-2 and TMPRSS-2 expression in different mouse models. ACE-2 and TMPRSS-2 expression was analyzed by immunostaining in a variety of tissues obtained from FVB/N mice undergoing either gonadectomy or sham-surgery and being subjected to ischemia–reperfusion injury or transverse aortic constriction surgery. In lung tissues sex did not have a significant impact on the expression of ACE-2 and TMPRSS-2. On the contrary, following myocardial injury, female sex was associated to a lower expression of ACE-2 at the level of the kidney tubules. In addition, after myocardial injury, a significant correlation between younger age and higher expression of both ACE-2 and TMPRSS-2 was observed for lung alveoli and bronchioli, kidney tubules, and liver sinusoids. Our experimental data indicate that gonadal hormones and biological sex do not alter ACE-2 and TMPRSS-2 expression in the respiratory tract in mice, independent of disease state. Thus, sex differences in ACE-2 and TMPRSS-2 protein expression observed in mice may not explain the higher disease burden of COVID-19 among men.

Alcohol-associated capillarization of sinusoids: A critique since the discovery by Schaffner and Popper in 1963.

This article reviews the literature on capillarization of hepatic sinusoids since its discovery in 1963. Liver sinusoidal endothelial cells are uniquely fenestrated and lack an underlying basement membrane. In chronic liver disease, the sinusoids capillarize and transform into systemic capillaries, a process termed capillarization of sinusoids. The histopathology is marked by defenestration, basement membrane formation, and space of Disse fibrogenesis. Capillarized sinusoids compromise the bidirectional exchange of materials between sinusoids and hepatocytes, leading to hepatocellular dysfunction. Sinusoidal capillarization was first described in active cirrhosis of alcoholics in 1963. Since then, it has been found in early and progressive stages of alcoholic hepatic fibrosis before the onset of cirrhosis. The sinusoidal structure is not altered in alcoholic steatosis without fibrosis. Defenestration impairs the ability of the endothelium to filter chylomicron remnants from sinusoids into the Disse's space, contributing to alcohol-induced postprandial hyperlipidemia and possibly atherosclerosis. Ethanol also modulates the fenestration dynamics in animals. In baboons, chronic alcohol consumption diminishes endothelial porosity in concomitance with hepatic fibrogenesis and in rats defenestrates the endothelium in the absence of fibrosis, and sometimes capillarizes the sinusoids. Acute ethanol ingestion enlarges fenestrations in rats and contracts fenestrations in rabbits. In sinusoidal endothelial cell culture, ethanol elicits fenestration dilation, which is likely related to its interaction with fenestration-associated cytoskeleton. Ethanol potentiates sinusoidal injury caused by cocaine, acetaminophen or lipopolysaccharide in mice and rats. Understanding ethanol's mechanisms on pathogenesis of sinusoidal capillarization and fenestration dynamics will lead to development of methods to prevent risks for atherosclerosis in alcoholism.