Phenotypic characterization of liver tissue heterogeneity through a next-generation 3D single-cell atlas.

Three-dimensional (3D) geometrical models are potent tools for quantifying complex tissue features and exploring structure-function relationships. However, these models are generally incomplete due to experimental limitations in acquiring multiple (> 4) fluorescent channels in thick tissue sections simultaneously. Indeed, predictive geometrical and functional models of the liver have been restricted to few tissue and cellular components, excluding important cellular populations such as hepatic stellate cells (HSCs) and Kupffer cells (KCs). Here, we combined deep-tissue immunostaining, multiphoton microscopy, deep-learning techniques, and 3D image processing to computationally expand the number of simultaneously reconstructed tissue structures. We then generated a spatial single-cell atlas of hepatic architecture (Hep3D), including all main tissue and cellular components at different stages of post-natal development in mice. We used Hep3D to quantitatively study 1) hepatic morphodynamics from early post-natal development to adulthood, and 2) the effect on the liver's overall structure when changing the hepatic environment after removing KCs. In addition to a complete description of bile canaliculi and sinusoidal network remodeling, our analysis uncovered unexpected spatiotemporal patterns of non-parenchymal cells and hepatocytes differing in size, number of nuclei, and DNA content. Surprisingly, we found that the specific depletion of KCs results in morphological changes in hepatocytes and HSCs. These findings reveal novel characteristics of liver heterogeneity and have important implications for both the structural organization of liver tissue and its function. Our next-gen 3D single-cell atlas is a powerful tool to understand liver tissue architecture, opening up avenues for in-depth investigations into tissue structure across both normal and pathological conditions.

Megavoltage radiotherapy effects on organs of the reticuloendothelial system.

PURPOSE: To study the uptake capacity of cells from the reticuloendothelial system after irradiation with high-energy X-rays. METHODS: Eighteen male Wistar rats were distributed in three groups: group A (n = 6): control, unirradiated animals studied alongside animals from group B; group B (n = 6) and group C (n = 6): animals irradiated and studied after 24 and 48 hours, respectively. The rats were anesthetized and placed on a 10 MV linear accelerator. Next, they were irradiated in the abdominal region, with 8 Gy. Twenty-four (groups A and B) and 48 hours later (group C), a colloidal carbon solution (1 mL/kg) was intravenously injected in the tail vein. Fifty minutes later, the spleens and livers were withdrawn and prepared to be studied. Kupffer cells and splenic macrophages containing carbon pigments were counted in an optical microscope. Arithmetic means were calculated for each group and compared among them. RESULTS: X-rays were associated with a reduced number of Kupffer cells containing colloidal carbon, proliferation and enlargement of biliary ducts, hypoplasia, and hepatocyte necrosis. In the irradiated spleen, the colloidal carbon uptake was concentrated in the marginal zone around the white pulp, with an inexpressive uptake of pigments by macrophages from white and red pulps. CONCLUSIONS: The X-rays in the rat abdomen are associated with a reduction in the Kupffer cells uptake of colloidal carbon, hepatocyte disorders, bile duct proliferation, and splenic uptake of colloidal carbon concentrated in the marginal zone.

Mucins Shed from the Laminated Layer in Cystic Echinococcosis Are Captured by Kupffer Cells via the Lectin Receptor Clec4F.

Cystic echinococcosis is caused by the larval stages (hydatids) of cestode parasites belonging to the species cluster Echinococcus granulosus sensu lato, with E. granulosus sensu stricto being the main infecting species. Hydatids are bladderlike structures that attain large sizes within various internal organs of livestock ungulates and humans. Hydatids are protected by the massive acellular laminated layer (LL), composed mainly of mucins. Parasite growth requires LL turnover, and abundant LL-derived particles are found at infection sites in infected humans, raising the question of how LL materials are dealt with by the hosts. In this article, we show that E. granulosus sensu stricto LL mucins injected into mice are taken up by Kupffer cells, the liver macrophages exposed to the vascular space. This uptake is largely dependent on the intact mucin glycans and on Clec4F, a C-type lectin receptor which, in rodents, is selectively expressed in Kupffer cells. This uptake mechanism operates on mucins injected both in soluble form intravenously (i.v.) and in particulate form intraperitoneally (i.p.). In mice harboring intraperitoneal infections by the same species, LL mucins were found essentially only at the infection site and in the liver, where they were taken up by Kupffer cells via Clec4F. Therefore, shed LL materials circulate in the host, and Kupffer cells can act as a sink for these materials, even when the parasite grows in sites other than the liver.

Megavoltage radiotherapy effects on organs of the reticuloendothelial system

Purpose: To study the uptake capacity of cells from the reticuloendothelial system after irradiation with high-energy X-rays. Methods: Eighteen male Wistar rats were distributed in three groups: group A (n = 6): control, unirradiated animals studied alongside animals from group B; group B (n = 6) and group C (n = 6): animals irradiated and studied after 24 and 48 hours, respectively. The rats were anesthetized and placed on a 10 MV linear accelerator. Next, they were irradiated in the abdominal region, with 8 Gy. Twenty-four (groups A and B) and 48 hours later (group C), a colloidal carbon solution (1 mL/kg) was intravenously injected in the tail vein. Fifty minutes later, the spleens and livers were withdrawn and prepared to be studied. Kupffer cells and splenic macrophages containing carbon pigments were counted in an optical microscope. Arithmetic means were calculated for each group and compared among them. Results: X-rays were associated with a reduced number of Kupffer cells containing colloidal carbon, proliferation and enlargement of biliary ducts, hypoplasia, and hepatocyte necrosis. In the irradiated spleen, the colloidal carbon uptake was concentrated in the marginal zone around the white pulp, with an inexpressive uptake of pigments by macrophages from white and red pulps. Conclusions: The X-rays in the rat abdomen are associated with a reduction in the Kupffer cells uptake of colloidal carbon, hepatocyte disorders, bile duct proliferation, and splenic uptake of colloidal carbon concentrated in the marginal zone.

Uptake of Plasmodium chabaudi hemozoin drives Kupffer cell death and fuels superinfections.

Kupffer cells (KCs) are self-maintained tissue-resident macrophages that line liver sinusoids and play an important role on host defense. It has been demonstrated that upon infection or intense liver inflammation, KCs might be severely depleted and replaced by immature monocytic cells; however, the mechanisms of cell death and the alterations on liver immunity against infections deserves further investigation. We explored the impact of acute Plasmodium infection on KC biology and on the hepatic immune response against secondary infections. Similar to patients, infection with Plasmodium chabaudi induced acute liver damage as determined by serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) elevation. This was associated with accumulation of hemozoin, increased of proinflammatory response and impaired bacterial and viral clearance, which led to pathogen spread to other organs. In line with this, mice infected with Plasmodium had enhanced mortality during secondary infections, which was associated with increased production of mitochondrial superoxide, lipid peroxidation and increased free iron within KCs-hallmarks of cell death by ferroptosis. Therefore, we revealed that accumulation of iron with KCs, triggered by uptake of circulating hemozoin, is a novel mechanism of macrophage depletion and liver inflammation during malaria, providing novel insights on host susceptibility to secondary infections. Malaria can cause severe liver damage, along with depletion of liver macrophages, which can predispose individuals to secondary infections and enhance the chances of death.

Susceptibility to Infections During Acute Liver Injury Depends on Transient Disruption of Liver Macrophage Niche.

Kupffer cells are the primary liver resident immune cell responsible for the liver firewall function, including clearance of bacterial infection from the circulation, as they are strategically positioned inside the liver sinusoid with intimate contact with the blood. Disruption in the tissue-resident macrophage niche, such as in Kupffer cells, can lead to a window of susceptibility to systemic infections, which represents a significant cause of mortality in patients with acetaminophen (APAP) overdose-induced acute liver injury (ALI). However, how Kupffer cell niche disruption increases susceptibility to systemic infections in ALI is not fully understood. Using a mouse model of ALI induced by APAP overdose, we found that Kupffer cells upregulated the apoptotic cell death program and were markedly reduced in the necrotic areas during the early stages of ALI, opening the niche for the infiltration of neutrophils and monocyte subsets. In addition, during the resolution phase of ALI, the remaining tissue macrophages with a Kupffer cell morphology were observed forming replicating cell clusters closer to necrotic areas devoid of Kupffer cells. Interestingly, mice with APAP-induced liver injury were still susceptible to infections despite the dual cellular input of circulating monocytes and proliferation of remaining Kupffer cells in the damaged liver. Therapy with bone marrow-derived macrophages (BMDM) was shown to be effective in occupying the niche devoid of Kupffer cells following APAP-induced ALI. The rapid BMDM migration to the liver and their positioning within necrotic areas enhanced the healing of the tissue and restored the liver firewall function after BMDM therapy. Therefore, we showed that disruption in the Kupffer cell niche and its impaired function during acute liver injury are key factors for the susceptibility to systemic bacterial infections. In addition, modulation of the liver macrophage niche was shown to be a promising therapeutic strategy for liver injuries that reduce the Kupffer cell number and compromise the organ function.

In the Acute Phase of Trypanosoma cruzi Infection, Liver Lymphoid and Myeloid Cells Display an Ambiguous Phenotype Combining Pro- and Anti-Inflammatory Markers.

Multiple cell populations, cellular biochemical pathways, and the autonomic nervous system contribute to maintaining the immunological tolerance in the liver. This tolerance is coherent because the organ is exposed to high levels of bacterial pathogen-associated molecular pattern (PAMP) molecules from the intestinal microbiota, such as lipopolysaccharide endotoxin (LPS). In the case of Trypanosoma cruzi infection, although there is a dramatic acute immune response in the liver, we observed intrahepatic cell populations combining pro- and anti-inflammatory markers. There was loss of fully mature Kupffer cells and an increase in other myeloid cells, which are likely to include monocytes. Among dendritic cells (DCs), the cDC1 population expanded relative to the others, and these cells lost both some macrophage markers (F4/80) and immunosuppressive cytokines (IL-10, TGF-ß1). In parallel, a massive T cell response occured with loss of naïve cells and increase in several post-activation subsets. However, these activated T cells expressed both markers programmed cell death protein (PD-1) and cytokines consistent with immunosuppressive function (IL-10, TGF-ß1). NK and NK-T cells broadly followed the pattern of T cell activation, while TCR-γδ cells appeared to be bystanders. While no data were obtained concerning IL-2, several cell populations also synthesized IFN-γ and TNF-α, which has been linked to host defense but also to tissue injury. It therefore appears that T. cruzi exerts control over liver immunity, causing T cell activation via cDC1 but subverting multiple populations of T cells into immunosuppressive pathways. In this way, T. cruzi engages a mechanism of hepatic T cell tolerance that is familiar from liver allograft tolerance, in which activation and proliferation are followed by T cell inactivation.

Aggregation of hepatic melanomacrophage centers in S. herzbergii (Pisces, Ariidae) as indicators of environmental change and well-being / [Agregação de centros de melanomacrófagos hepáticos em S. herzbergii (Pisces, Ariidae) como indicadores de mudança ambiental e de bem-estar]

The melanomacrophage centers (MMCs) in the liver of fish are indicators of environmental conditions, as they are involved in xenobiotic biotransformation. The objective of this study was to evaluate the number of MMC in the liver of juveniles and adults of Sciades herzbergii from areas with different levels of contamination. The fish were caught at three points (reference - A1, potentially impacted - A2 and contaminated - A3), in São José bay (Maranhão, Brazil), in four samples. The livers were subjected to the standard histological procedure and 5µm sections were stained with hematoxylin-eosin. In livers of A2 adult individuals (260.50±161.50 MMCs / mm²) they presented a greater number of MMCs when compared to A3 adults (60.00 ± 30.10 MMCs / mm²). Juveniles showed considerable values in A1 (100.00 ± 0.00 MMCs/mm²) and A2 (95.33 ± 33.00 MMCs / mm²) compared to juveniles in A3 (49.00±0.00 MMCs/mm²). These high values are unexpected for young people. The average number of MMC correlated with the rainy season in the region. The use of hepatic MMCs as a biomarker of exposure to pollutants, in particular substances from fisheries systems, such as ammonia and nitrite, proved to be adequate to differentiate areas with different levels of impacts.(AU)

Os centros melanomacrófagos (MMCs) no fígado de peixes são indicadores das condições ambientais, pois estão envolvidos na biotransformação xenobiótica. O objetivo deste estudo foi avaliar o número de MMC no fígado de juvenis e adultos de Sciades herzbergii de áreas com diferentes níveis de contaminação. Os peixes foram capturados em três pontos (referência - A1; potencialmente impactado - A2; e contaminado - A3), na baía de São José (Maranhão, Brasil), em quatro amostras. Os fígados foram submetidos ao procedimento histológico padrão e cortes de 5µm foram corados com hematoxilina-eosina. Em fígados de indivíduos adultos A2 (260,50±161,50 MMCs/mm²), eles apresentaram maior número de MMCs quando comparados aos adultos A3 (60,00±30,10 MMCs/mm²). Os juvenis apresentaram valores elevados em A1 (100,00 ± 0,00 MMCs/mm²) e A2 (95,33±33,00 MMCs/mm²) quando comparados aos juvenis em A3 (49,00±0,00 MMCs/mm²). Esses altos valores são inesperados para os jovens. O número médio de MMC correlacionou-se com a época chuvosa na região. A utilização de MMCs hepáticos como biomarcador de exposição a poluentes, em particular substâncias provenientes de sistemas pesqueiros, como amônia e nitrito, mostrou-se adequada para diferenciar áreas com diferentes níveis de impactos.(AU)

Chemical hypoxia induces pro-inflammatory signals in fat-laden hepatocytes and contributes to cellular crosstalk with Kupffer cells through extracellular vesicles.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is associated to intermittent hypoxia (IH) and is an aggravating factor of non-alcoholic fatty liver disease (NAFLD). We investigated the effects of hypoxia in both in vitro and in vivo models of NAFLD. METHODS: Primary rat hepatocytes treated with free fatty acids (FFA) were subjected to chemically induced hypoxia (CH) using the hypoxia-inducible factor-1 alpha (HIF-1α) stabilizer cobalt chloride (CoCl2). Triglyceride (TG) content, mitochondrial superoxide production, cell death rates, cytokine and inflammasome components gene expression and protein levels of cleaved caspase-1 were assessed. Also, Kupffer cells (KC) were treated with conditioned medium (CM) and extracellular vehicles (EVs) from hypoxic fat-laden hepatic cells. The choline deficient L-amino acid defined (CDAA)-feeding model used to assess the effects of IH on experimental NAFLD in vivo. RESULTS: Hypoxia induced HIF-1α in cells and animals. Hepatocytes exposed to FFA and CoCl2 exhibited increased TG content and higher cell death rates as well as increased mitochondrial superoxide production and mRNA levels of pro-inflammatory cytokines and of inflammasome-components interleukin-1ß, NLRP3 and ASC. Protein levels of cleaved caspase-1 increased in CH-exposed hepatocytes. CM and EVs from hypoxic fat-laden hepatic cells evoked a pro-inflammatory phenotype in KC. Livers from CDAA-fed mice exposed to IH exhibited increased mRNA levels of pro-inflammatory and inflammasome genes and increased levels of cleaved caspase-1. CONCLUSION: Hypoxia promotes inflammatory signals including inflammasome/caspase-1 activation in fat-laden hepatocytes and contributes to cellular crosstalk with KC by release of EVs. These mechanisms may underlie the aggravating effect of OSAS on NAFLD. [Abstract word count: 257].

In the presence of Trypanosoma cruzi antigens, activated peripheral T lymphocytes retained in the liver induce a proinflammatory phenotypic and functional shift in intrahepatic T lymphocyte.

In secondary lymphoid organs, pathogen-derived and endogenous danger molecules are recognized by pattern recognition receptors, leading to adaptive proinflammatory immune responses. This conceptual rule does not apply directly to the liver, as hepatic immune cells tolerate gut-derived bacterial molecules from the flora. Therefore, the recognition of danger and proinflammatory stimuli differs between the periphery and the liver. However, the tolerant nature of the liver must be overcome in the case of infections or cancer, for example. The central paradigm is the basis for danger recognition and the balance between inflammation and tolerance in the liver. Here, we observed functional integration, with activated peripheral T lymphocytes playing a role in the induction of a proinflammatory environment in the liver in the presence of Trypanosoma cruzi antigens. When only parasite extract was orally administered, it led to the up-regulation of hepatic tolerance markers, but oral treatment plus adoptively transferred activated splenic T lymphocytes led to a proinflammatory response. Moreover, treated/recipient mice showed increased levels of TNF, IFN-γ, IL-6, and CCL2 in the liver and increased numbers of effector and/or effector memory T lymphocytes and F4/80+ cells. There was a reduction in FoxP3+ Treg cells, NKT cells, and γδ T lymphocytes with increased liver damage in the presence of activated peripheral T cells. Our results show that the induction of a proinflammatory liver response against T. cruzi danger molecules is at least partially dependent on cooperation with activated peripheral T cells.

High prevalence of hepatic steatosis and vascular thrombosis in COVID-19: A systematic review and meta-analysis of autopsy data.

BACKGROUND: Coronavirus disease 2019 (COVID-19) disease can frequently affect the liver. Data on hepatic histopathological findings in COVID-19 is scarce. AIM: To characterize hepatic pathological findings in patients with COVID-19. METHODS: We conducted a systematic review with meta-analysis registered on PROSPERO (CRD42020192813), following PRISMA guidelines. Eligible trials were those including patients of any age and COVID-19 diagnosis based on a molecular test. Histopathological reports from deceased COVID-19 patients undergoing autopsy or liver biopsy were reviewed. Articles including less than ten patients were excluded. Proportions were pooled using random-effects models. Q statistic and I 2 were used to assess heterogeneity and levels of evidence, respectively. RESULTS: We identified 18 studies from 7 countries; all were case reports and case series from autopsies. All the patients were over 15 years old, and 67.2% were male. We performed a meta-analysis of 5 studies, including 116 patients. Pooled prevalence estimates of liver histopathological findings were hepatic steatosis 55.1% [95% confidence interval (CI): 46.2-63.8], congestion of hepatic sinuses 34.7% (95%CI: 7.9-68.4), vascular thrombosis 29.4% (95%CI: 0.4-87.2), fibrosis 20.5% (95%CI: 0.6-57.9), Kupffer cell hyperplasia 13.5% (95%CI: 0.6-54.3), portal inflammation 13.2% (95%CI: 0.1-48.8), and lobular inflammation 11.6% (95%CI: 0.3-35.7). We also identified the presence of venous outflow obstruction, phlebosclerosis of the portal vein, herniated portal vein, periportal abnormal vessels, hemophagocytosis, and necrosis. CONCLUSION: We found a high prevalence of hepatic steatosis and vascular thrombosis as major histological liver features. Other frequent findings included portal and lobular inflammation and Kupffer cell hyperplasia or proliferation. Further studies are needed to establish the mechanisms and implications of these findings.

Hypoxia-Inducible Factor-2α Reprograms Liver Macrophages to Protect Against Acute Liver Injury Through the Production of Interleukin-6.

BACKGROUND AND AIMS: Acetaminophen (APAP) overdose represents the most frequent cause of acute liver failure, resulting in death or liver transplantation in more than one third of patients in the United States. The effectiveness of the only antidote, N-acetylcysteine, declines rapidly after APAP ingestion, long before patients are admitted to the clinic with symptoms of severe liver injury. The direct hepatotoxicity of APAP triggers a cascade of innate immune responses that may exacerbate or limit the progression of tissue damage. A better understanding of this complex mechanism will help uncover targets for therapeutic interventions. APPROACH AND RESULTS: We observed that APAP challenge caused stabilization of hypoxia-inducible factors (HIFs) in the liver and hepatic macrophages (MΦs), particularly HIF-2α. Genetic deletion of the HIF-2α gene in myeloid cells (HIF-2αmye/- ) markedly exacerbated APAP-induced liver injury (AILI) without affecting APAP bioactivation and detoxification. In contrast, hepatic and serum levels of the hepatoprotective cytokine interleukin 6 (IL-6), its downstream signal transducer and transcription factor 3 activation in hepatocytes, as well as hepatic MΦ IL-6 expression were markedly reduced in HIF-2αmye/- mice compared to wild-type mice post-APAP challenge. In vitro experiments revealed that hypoxia induced IL-6 production in hepatic MΦs and that such induction was abolished in HIF-2α-deleted hepatic MΦs. Restoration of IL-6 by administration of exogenous IL-6 ameliorated AILI in HIF-2αmye/- mice. Finally, IL-6-mediated hepatoprotection against AILI was abolished in hepatocyte-specific IL-6 receptor knockout mice. CONCLUSIONS: The data demonstrate that APAP treatment leads to HIF-2α stabilization in hepatic MΦs and that HIF-2α subsequently reprograms hepatic MΦs to produce the hepatoprotective cytokine IL-6, thereby ameliorating AILI.

Dietary Lipids Differentially Shape Nonalcoholic Steatohepatitis Progression and the Transcriptome of Kupffer Cells and Infiltrating Macrophages.

A crucial component of nonalcoholic fatty liver disease (NAFLD) pathogenesis is lipid stress, which may contribute to hepatic inflammation and activation of innate immunity in the liver. However, little is known regarding how dietary lipids, including fat and cholesterol, may facilitate innate immune activation in vivo. We hypothesized that dietary fat and cholesterol drive NAFLD progression to steatohepatitis and hepatic fibrosis by altering the transcription and phenotype of hepatic macrophages. This hypothesis was tested by using RNA-sequencing methods to characterize and analyze sort-purified hepatic macrophage populations that were isolated from mice fed diets with varying amounts of fat and cholesterol. The addition of cholesterol to a high-fat diet triggered hepatic pathology reminiscent of advanced nonalcoholic steatohepatitis (NASH) in humans characterized by signs of cholesterol dysregulation, generation of oxidized low-density lipoprotein, increased recruitment of hepatic macrophages, and significant fibrosis. RNA-sequencing analyses of hepatic macrophages in this model revealed that dietary cholesterol induced a tissue repair and regeneration phenotype in Kupffer cells (KCs) and recruited infiltrating macrophages to a greater degree than fat. Furthermore, comparison of diseased KCs and infiltrating macrophages revealed that these two macrophage subsets are transcriptionally diverse. Finally, direct stimulation of murine and human macrophages with oxidized low-density lipoprotein recapitulated some of the transcriptional changes observed in the RNA-sequencing study. These findings indicate that fat and cholesterol synergize to alter macrophage phenotype, and they also challenge the dogma that KCs are purely proinflammatory in NASH. Conclusion: This comprehensive view of macrophage populations in NASH indicates mechanisms by which cholesterol contributes to NASH progression and identifies potential therapeutic targets for this common disease.

Preparation of Zoledronate liposome and its impact on apoptosis of Kupffer cells in rat liver

Purpose:To establish a method for the preparation of zoledronate liposome and to observe its effect on inducing the apoptosis of rat liver Kupffer cells.Methods:Zoledronate was encapsulated in liposomes, and then the entrapment rate was detected on a spectrophotometer. The prepared Zoledronate liposome (0.01 mg/mL) was injected into the tail vein of SD rats. Three days later, the number of Kupffer cells (CD68 positive) in rat liver tissue was detected by immunohistochemistry. Flow cytometry was used to detect the apoptosis rate of the isolated liver Kupffer cell cultured in vitro.Results:The entrapment rate of Zoledronate was 43.4±7.8%. Immunohistochemistry revealed that the number of Kupffer cells was 19.3±2.1 in PBS group and 5.5±1.7 in Zoledronate liposome group, with a significant difference (P<0.05). The apoptosis rate of Kupffer cells was 4.1±0.8% in PBS group, while it was 9±2.2% and 23.3±5.9% in Zoledronate liposomes groups with different concentrations of Zoledronate liposome (P<0.05).Conclusions:Zoledronate liposomes can effectively induce the apoptosis of Kupffer cells in vivo and in vitro, and the apoptosis rate is related to the concentration of Zoledronate liposome. To establish a rat liver Kupffer cell apoptosis model can provide a new means for further study on Kupffer cell function.(AU)

Preparation of Zoledronate liposome and its impact on apoptosis of Kupffer cells in rat liver

Abstract Purpose: To establish a method for the preparation of zoledronate liposome and to observe its effect on inducing the apoptosis of rat liver Kupffer cells. Methods: Zoledronate was encapsulated in liposomes, and then the entrapment rate was detected on a spectrophotometer. The prepared Zoledronate liposome (0.01 mg/mL) was injected into the tail vein of SD rats. Three days later, the number of Kupffer cells (CD68 positive) in rat liver tissue was detected by immunohistochemistry. Flow cytometry was used to detect the apoptosis rate of the isolated liver Kupffer cell cultured in vitro. Results: The entrapment rate of Zoledronate was 43.4±7.8%. Immunohistochemistry revealed that the number of Kupffer cells was 19.3±2.1 in PBS group and 5.5±1.7 in Zoledronate liposome group, with a significant difference (P<0.05). The apoptosis rate of Kupffer cells was 4.1±0.8% in PBS group, while it was 9±2.2% and 23.3±5.9% in Zoledronate liposomes groups with different concentrations of Zoledronate liposome (P<0.05). Conclusions: Zoledronate liposomes can effectively induce the apoptosis of Kupffer cells in vivo and in vitro, and the apoptosis rate is related to the concentration of Zoledronate liposome. To establish a rat liver Kupffer cell apoptosis model can provide a new means for further study on Kupffer cell function.

Gadolinium Chloride Rescues Niemann⁻Pick Type C Liver Damage.

Niemann⁻Pick type C (NPC) disease is a rare neurovisceral cholesterol storage disorder that arises from loss of function mutations in the NPC1 or NPC2 genes. Soon after birth, some patients present with an aggressive hepatosplenomegaly and cholestatic signs. Histopathologically, the liver presents with large numbers of foam cells; however, their role in disease pathogenesis has not been explored in depth. Here, we studied the consequences of gadolinium chloride (GdCl3) treatment, a well-known Kupffer/foam cell inhibitor, at late stages of NPC liver disease and compared it with NPC1 genetic rescue in hepatocytes in vivo. GdCl3 treatment successfully blocked the endocytic capacity of hepatic Kupffer/foam measured by India ink endocytosis, decreased the levels CD68-A marker of Kupffer cells in the liver-and normalized the transaminase levels in serum of NPC mice to a similar extent to those obtained by genetic Npc1 rescue of liver cells. Gadolinium salts are widely used as magnetic resonance imaging (MRI) contrasts. This study opens the possibility of targeting foam cells with gadolinium or by other means for improving NPC liver disease. Synopsis: Gadolinium chloride can effectively rescue some parameters of liver dysfunction in NPC mice and its potential use in patients should be carefully evaluated.

Liver HLA-E Expression Is Associated with Severity of Liver Disease in Chronic Hepatitis C.

Hepatitis C virus (HCV) can escape from innate and adaptive immunity, making the immune response ineffective. Human leukocyte antigen E (HLA-E) might regulate the antiviral function of immune response and contribute to the persistence of HCV and the severity of liver disease. This study aimed to evaluate the expression of HLA-E in the liver and its association with the severity of liver disease in HCV patients. We performed a retrospective analysis of liver biopsies from 125 HCV patients and from 20 control subjects without liver disease. Liver biopsies were reviewed and classified according to severity of fibrosis and inflammatory activity. The pathologist assessed the magnitude of HLA-E expression in a semiquantitative way, attributing scores from 0 to 3. Immunohistochemistry showed positive for HLA-E in hepatocyte and Kupffer cells. The rate of HLA-E positivity in hepatocytes and Kupffer cells was significantly higher in HCV patients compared to controls. The liver samples classified as severe fibrosis and necroinflammatory activity presented greater expression of HLA-E on Kupffer cells and hepatocytes, with a significant linear association. It indicates that HLA-E expression may have an immunomodulatory effect and a possible role in the severity of liver disease in chronic hepatitis C.

Preparation of Zoledronate liposome and its impact on apoptosis of Kupffer cells in rat liver.

PURPOSE: To establish a method for the preparation of zoledronate liposome and to observe its effect on inducing the apoptosis of rat liver Kupffer cells. METHODS: Zoledronate was encapsulated in liposomes, and then the entrapment rate was detected on a spectrophotometer. The prepared Zoledronate liposome (0.01 mg/mL) was injected into the tail vein of SD rats. Three days later, the number of Kupffer cells (CD68 positive) in rat liver tissue was detected by immunohistochemistry. Flow cytometry was used to detect the apoptosis rate of the isolated liver Kupffer cell cultured in vitro. RESULTS: The entrapment rate of Zoledronate was 43.4±7.8%. Immunohistochemistry revealed that the number of Kupffer cells was 19.3±2.1 in PBS group and 5.5±1.7 in Zoledronate liposome group, with a significant difference (P<0.05). The apoptosis rate of Kupffer cells was 4.1±0.8% in PBS group, while it was 9±2.2% and 23.3±5.9% in Zoledronate liposomes groups with different concentrations of Zoledronate liposome (P<0.05). CONCLUSIONS: Zoledronate liposomes can effectively induce the apoptosis of Kupffer cells in vivo and in vitro, and the apoptosis rate is related to the concentration of Zoledronate liposome. To establish a rat liver Kupffer cell apoptosis model can provide a new means for further study on Kupffer cell function.

Characterization and frequency of histological changes in bovine livers from slaughterhouses in Brazil kept on Brachiaria spp / Caracterização e frequência das alterações histológicas nos fígados de bovinos mantidos em pastagens de Brachiaria spp. provenientes de abatedouros no Brasil

Background: Brachiaria spp. is the main pasture for ruminant productions in Brazil, but the limiting factor for its use is the toxicity due to the presence of steroidal saponins. Chronic ingestion of Brachiaria spp. by cattle may cause liver changes such as fibrosis, bile duct proliferation and clusters of foamy macrophages in the hepatic parenchyma. The main objective of the present study was to evaluate the most frequent histological changes and their frequencies in livers collected in abattoirs in Brazil from beef cattle raised exclusively on Brachiaria spp. and compare them with those observed in animals kept in Andropogon spp. grass and native pastures in Rio Grande do Sul.Materials, Methods & Results: Liver samples without macroscopic changes were collected in abattoirs from 561 healthy Nelore and Nelore crossbred cattle raised in Brachiaria spp. pastures from Mato Grosso (MT), Mato Grosso do Sul (MS), Minas Gerais (MG) and Pará (PA) States. Liver samples from 84 Angus cattle (Bos taurus) kept on native pastures in Rio Grande do Sul (RS) and from 60 Nelore and Nelore crossbreed cattle raised in Andropogon spp. pastures in Tocantins State (TO) were collected as control. Semi-quantitative analysis of the histopathological changes were proceeded: (-) = no change; (+) = slight or discreet change; (++) = moderate change and (+++) = marked change. The main histopathological [...]