Rat Hepatocytes Research Articles

FORMULATION AND NUTRITIONAL EVALUATION OF HIGH-FAT DIET FEED FOR FATTY LIVER INDUCEMENT IN RODENT MODELS

FORMULATION AND NUTRITIONAL EVALUATION OF HIGH-FAT DIET FEED FOR FATTY LIVER INDUCEMENT IN RODENT MODELS

Mode of action analysis for fluxapyroxad-induced rat liver tumour formation: evidence for activation of the constitutive androstane receptor and assessment of human relevance

The fungicide fluxapyroxad (BAS 700 F) has been shown to significantly increase the incidence of liver tumours in male Wistar rats at dietary levels of 1500 and 3000 ppm and in female rats at a dietary level of 3000 ppm via a non-genotoxic mechanism. In order to elucidate the mode of action (MOA) for fluxapyroxad-induced rat liver tumour formation a series of in vivo and in vitro investigative studies were undertaken. The treatment of male and female Wistar rats with diets containing 0 (control), 50, 250, 1500 and 3000 ppm fluxapyroxad for 1, 3, 7 and 14 days resulted in a dose-dependent increases in relative weight at 1500 and 3000 ppm from day 3 onwards in both sexes, with an increase in relative liver weight being also observed in male rats given 250 ppm fluxapyroxad for 14 days. Examination of liver sections revealed a centrilobular hepatocyte hypertrophy in some fluxapyroxad treated male and female rats. Hepatocyte replicative DNA synthesis (RDS) was significantly increased in male rats given 1500 and 3000 ppm fluxapyroxad for 3 and 7 days and in female rats given 50–3000 ppm fluxapyroxad for 7 days and 250–3000 ppm fluxapyroxad for 3 and 14 days; the maximal increases in RDS in both sexes being observed after 7 days treatment. The treatment of male and female Wistar rats with 250–3000 ppm fluxapyroxad for 14 days resulted in significant increases in hepatic microsomal total cytochrome P450 (CYP) content and CYP2B subfamily-dependent enzyme activities. Male Wistar rat hepatocytes were treated with control medium and medium containing 1–100 μM fluxapyroxad or 500 μM sodium phenobarbital (NaPB) for 4 days. Treatment with fluxapyroxad and NaPB increased CYP2B and CYP3A enzyme activities and mRNA levels but had little effect on markers of CYP1A and CYP4A subfamily enzymes and of the peroxisomal fatty acid β-oxidation cycle. Hepatocyte RDS was significantly increased by treatment with fluxapyroxad, NaPB and 25 ng/ml epidermal growth factor (EGF). The treatment of hepatocytes from two male human donors with 1–100 μM fluxapyroxad or 500 μM NaPB for 4 days resulted in some increases in CYP2B and CYP3A enzyme activities and CYP mRNA levels but had no effect on hepatocyte RDS, whereas treatment with EGF resulted in significant increase in RDS in both human hepatocyte preparations. Hepatocytes from male Sprague-Dawley wild type (WT) and constitutive androstane receptor (CAR) knockout (CAR KO) rats were treated with control medium and medium containing 1–16 μM fluxapyroxad or 500 μM NaPB for 4 days. While both fluxapyroxad and NaPB increased CYP2B enzyme activities and mRNA levels in WT hepatocytes, only minor effects were observed in CAR KO rat hepatocytes. Treatment with both fluxapyroxad and NaPB only increased RDS in WT and not in CAR KO rat hepatocytes, whereas treatment with EGF increased RDS in both WT and CAR KO rat hepatocytes. In conclusion, a series of in vivo and in vitro investigative studies have demonstrated that fluxapyroxad is a CAR activator in rat liver, with similar properties to the prototypical CAR activator phenobarbital. A robust MOA for fluxapyroxad-induced rat liver tumour formation has been established. Based on the lack of effect of fluxapyroxad on RDS in human hepatocytes, it is considered that the MOA for fluxapyroxad-induced liver tumour formation is qualitatively not plausible for humans.

Fatty acids in Plantago asiatica seeds are responsible for the production of the pro-inflammatory mediator nitric oxide

Background: Plantago asiatica L. (Plantaginaceae) commonly grows in East Asia, with its seeds (Shazenshi), having been used as diuretic and anti-inflammatory drugs in traditional Japanese medicine. It is not known which constituents of P. asiatica seeds elicit the anti-inflammatory effects, such as reduced expression of the inducible nitric oxide synthase (iNOS) in interleukin (IL)-1β-treated hepatocytes which leads to a reduction in the pro-inflammatory mediator nitric oxide (NO). Objective: To identify the anti-inflammatory constituents of P. asiatica seeds, the anti-inflammatory activity of purified constituents was determined by assaying NO production in IL-1β-treated hepatocytes. Methods: P. asiatica seeds were extracted with 50% methanol and successively fractionated into three crude fractions with ethyl acetate (EtOAc) and n-butanol. The compounds were methylated and analyzed by gas chromatography–mass spectrometry (GC–MS). Primary cultured rat hepatocytes were prepared by collagenase perfusion, and P. asiatica seed extract (PASE), a fraction, or a compound was added to the culture medium with IL-1β and incubated at 37 °C. Potency of each fraction was determined by the Griess method for measuring the levels of nitrite in the medium. Results: PASE suppressed IL-1β-induced NO production without showing cytotoxicity, and an EtOAc-soluble fraction of PASE significantly inhibited NO production. GC–MS analysis detected 26 distinct fatty acids as their methyl esters in this fraction. Among them, three unsaturated fatty acids (linoleic, oleic, and α-linolenic acids) and palmitic acid were abundant. These unsaturated fatty acids are known to reduce NO levels. In contrast, acteoside and aucubin, which are thought to be present in the n-butanol-soluble fraction, showed only a low level of NO production suppression. Conclusion: The EtOAc-soluble fraction of PASE included many fatty acids, which may suppress the production of NO. The results imply that the anti-inflammatory activity of P. asiatica seeds may be produced by three unsaturated fatty acids. Because the fatty acids are abundant in the seeds of medicinal plants, they are likely to contribute to anti-inflammatory activity of the seeds. Keywords: Plantain seed, polyunsaturated fatty acid, Kampo medicine, hepatocyte, nitric oxide.

Hepatoprotective effects of baicalein against liver ischemia-reperfusion injury and partial hepatectomy in a rat model.

Baicalein is the main active flavonoid in Scutellariae Radix and is included in shosaikoto, a Kampo formula used for treating hepatitis and jaundice. However, little is known about its hepatoprotective effects against hepatic ischemia-reperfusion injury (HIRI), a severe clinical condition directly caused by interventional procedures. We aimed to investigate the hepatoprotective effects of baicalein against HIRI and partial hepatectomy (HIRI + PH) and its potential underlying mechanisms. Male Sprague-Dawley rats received either baicalein (5mg/kg) or saline intraperitoneally and underwent a 70% hepatectomy 15min after hepatic ischemia. After reperfusion, liver and blood samples were collected. Survival was monitored 30min after hepatic ischemia and hepatectomy. In interleukin 1β (IL-1β)-treated primary cultured rat hepatocytes, the influence of baicalein on inflammatory mediator production and the associated signaling pathway was analyzed. Baicalein suppressed apoptosis and neutrophil infiltration, which are the features of HIRI + PH treatment-induced histological injury. Baicalein also reduced the mRNA expression of the proinflammatory cytokine tumor necrosis factor-α (TNF-α). In addition, HIRI + PH treatment induced liver enzyme deviations in the serum and hypertrophy of the remnant liver, which were suppressed by baicalein. In the lethal HIRI + PH treatment group, baicalein significantly reduced mortality. In IL-1β-treated rat hepatocytes, baicalein suppressed TNF-α and chemokine mRNA expression as well as the activation of nuclear factor-kappa B (NF-κB) and Akt. Baicalein treatment attenuates HIRI + PH-induced liver injury and may promote survival. This potential hepatoprotection may be partly related to suppressing inflammatory gene induction through the inhibition of NF-κB activity and Akt signaling in hepatocytes.

A Novel Role for the Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Delta Isoform in Hepatocellular Proliferation

The phosphatidylinositol-4,5-bisphosphate 3-kinase delta isoform (Pik3cd), usually considered immune-specific, was unexpectedly identified as a gene potentially related to either regeneration and/or differentiation in animals lacking hepatocellular Integrin Linked Kinase (ILK). Since a specific inhibitor (Idelalisib, or CAL101) for the catalytic subunit encoded by Pik3cd (p110δ) has reported hepatotoxicity when used for treating Chronic Lymphocytic Leukemia and other lymphomas, we aimed to elucidate if there is a role for p110δ in normal liver function. To determine the effect on normal liver regeneration, partial hepatectomy (PHx) was performed using mice in which p110δ was first inhibited using CAL101. Inhibition led to over a 50% decrease in proliferating hepatocytes in the first two days after PHx. This difference correlated with phosphorylation changes in the HGF and EGF receptors (MET and EGFR, respectively) and NF-κB signaling. Ingenuity Pathway Analyses implicated C/EBPβ, HGF and the EGFR heterodimeric partner, ERBB2, as three of the top 20 regulators downstream of p110δ signaling as their pathways were suppressed in the presence of CAL101 at one day post-PHx. A regulatory role for p110δ signaling in mouse and rat hepatocytes through MET and EGFR was further verified using hepatocyte primary cultures, in the presence or absence of CAL101. Combined, this data supports a role for p110δ as a downstream regulator of normal hepatocytes when stimulated to proliferate.

Hyaluronic acid modified extracellular vesicles targeting hepatic stellate cells to attenuate hepatic fibrosis

RationaleTransforming growth factor-beta1 (TGF-β1) plays a pivotal role in promoting hepatic fibrosis, pirfenidone (PFD) could inhibit TGF-β1 signaling pathway to alleviate hepatic stellate cells (HSC) activation mediated hepatic fibrosis. The targeting delivery strategy of PFD to hepatic stellate cells is a challenge. Extracellular vesicles (EVs), cell-derived membranous particles are intraluminal nano-vesicles that play a vital role in intercellular communication, they also be considered as an ideal nano-carrier. MethodsIn this study, we developed a target strategy to deliver PFD to HSC with CD44 over-expression by EVs, hyaluronic acid (HA) modified DSPE-PEG2000 endows the active targeting ability of activated HSCs to PFD-loaded EVs. ResultsIn both rat hepatic stellate cell line HSC-T6 and rat hepatocyte cell line BRL, HA@EVs-PFD demonstrated the capacity to down-regulate the expression of collagen-synthesis-related proteins and showed superior inhibition efficacy of HSC-T6 activation compared to free PFD. In hepatic fibrosis model, 4 weeks of HA@EVs-PFD treatment resulted in a reduction in liver collagen fibers, significant improvement in hepatic cell morphology, and amelioration of hepatic fibrosis. ConclusionsHA@EVs-PFD, as a drug delivery system that effectively targets and inhibits activated HSCs to treat hepatic fibrosis, holds promise as a potential therapeutic agent against hepatic fibrosis.

A novel inhibitor of the mitochondrial respiratory complex I with uncoupling properties exerts potent antitumor activity

Cancer cells are highly dependent on bioenergetic processes to support their growth and survival. Disruption of metabolic pathways, particularly by targeting the mitochondrial electron transport chain complexes (ETC-I to V) has become an attractive therapeutic strategy. As a result, the search for clinically effective new respiratory chain inhibitors with minimized adverse effects is a major goal. Here, we characterize a new OXPHOS inhibitor compound called MS-L6, which behaves as an inhibitor of ETC-I, combining inhibition of NADH oxidation and uncoupling effect. MS-L6 is effective on both intact and sub-mitochondrial particles, indicating that its efficacy does not depend on its accumulation within the mitochondria. MS-L6 reduces ATP synthesis and induces a metabolic shift with increased glucose consumption and lactate production in cancer cell lines. MS-L6 either dose-dependently inhibits cell proliferation or induces cell death in a variety of cancer cell lines, including B-cell and T-cell lymphomas as well as pediatric sarcoma. Ectopic expression of Saccharomyces cerevisiae NADH dehydrogenase (NDI-1) partially restores the viability of B-lymphoma cells treated with MS-L6, demonstrating that the inhibition of NADH oxidation is functionally linked to its cytotoxic effect. Furthermore, MS-L6 administration induces robust inhibition of lymphoma tumor growth in two murine xenograft models without toxicity. Thus, our data present MS-L6 as an inhibitor of OXPHOS, with a dual mechanism of action on the respiratory chain and with potent antitumor properties in preclinical models, positioning it as the pioneering member of a promising drug class to be evaluated for cancer therapy.MS-L6 exerts dual mitochondrial effects: ETC-I inhibition and uncoupling of OXPHOS. In cancer cells, MS-L6 inhibited ETC-I at least 5 times more than in isolated rat hepatocytes. These mitochondrial effects lead to energy collapse in cancer cells, resulting in proliferation arrest and cell death. In contrast, hepatocytes which completely and rapidly inactivated this molecule, restored their energy status and survived exposure to MS-L6 without apparent toxicity.

Novel Inositol 1,4,5-Trisphosphate Receptor Inhibitor Antagonizes Hepatic Stellate Cell Activation: A Potential Drug to Treat Liver Fibrosis.

Liver fibrosis, characterized by excessive extracellular matrix (ECM) deposition, can progress to cirrhosis and increases the risk of liver cancer. Hepatic stellate cells (HSCs) play a pivotal role in fibrosis progression, transitioning from a quiescent to activated state upon liver injury, wherein they proliferate, migrate, and produce ECM. Calcium signaling, involving the inositol 1,4,5-trisphosphate receptor (IP3R), regulates HSC activation. This study investigated the efficacy of a novel IP3R inhibitor, desmethylxestospongin B (dmXeB), in preventing HSC activation. Freshly isolated rat HSCs were activated in vitro in the presence of varying dmXeB concentrations. The dmXeB effectively inhibited HSC proliferation, migration, and expression of fibrosis markers without toxicity to the primary rat hepatocytes or human liver organoids. Furthermore, dmXeB preserved the quiescent phenotype of HSCs marked by retained vitamin A storage. Mechanistically, dmXeB suppressed mitochondrial respiration in activated HSCs while enhancing glycolytic activity. Notably, methyl pyruvate, dimethyl α-ketoglutarate, and nucleoside supplementation all individually restored HSC proliferation despite dmXeB treatment. Overall, dmXeB demonstrates promising anti-fibrotic effects by inhibiting HSC activation via IP3R antagonism without adverse effects on other liver cells. These findings highlight dmXeB as a potential therapeutic agent for liver fibrosis treatment, offering a targeted approach to mitigate liver fibrosis progression and its associated complications.

Mitochondrial dysfunction of the inner membrane of hepatocytes in the development of glutamate-induced steatohepatosis and its correction

Elucidation of the mechanisms of the development of liver steatosis, which are at the heart of the pathogenesis of nonalcoholic fatty liver disease (NAFLD), will allow the introduction of new effective treatment methods into medical practice, as well as the development of new measures for the correction of this disease and accompanying pathologies. The purpose of the research is to establish the enzymatic activity of the complexes of the electron transport chain of the mitochondrial membrane of rat hepatocytes and to evaluate the corrective effect of the multiprobiotic “Symbiter acidophilic” concentrated or nanocrystalline cerium dioxide on the formation of steatohepatosis induced by neonatal sodium glutamate administration. The experiments were carried out on 50 white non-linear male rats; the direction included the study of the mechanisms of the development of steatohepatosis in 4-month-old rats, which were administered monosodium glutamate in the neonatal period, and the study of the functional state of the liver in rats after the neonatal administration of monosodium glutamate against the background of periodic administration of a multiprobiotic or nanocrystalline dioxide cerium. It was established that neonatal administration of monosodium glutamate causes metabolic changes in 4-month-old rats, manifested in the disproportionate accumulation of fat with the development of visceral obesity without hyperphagia, dyslipidemia, and steatohepatosis. In 4-month-old rats, after neonatal administration of sodium glutamate, the development of steatohepatosis was accompanied by mitochondrial dysfunction, which was manifested by changes in the lipid composition of the inner membrane of hepatocyte mitochondria with an increase in oxidized products and a change in the enzymatic activity of all complexes of the respiratory chain. In rats injected with monosodium glutamate in the neonatal period, periodic use of the multiprobiotic “Symbiter acidophilic” concentrated or nanocrystalline cerium dioxide significantly restored the functional state of the liver, reduced the manifestations of oxidative stress and prevented the development of steatohepatosis, which indicates the antioxidant effect of these drugs and the possibility of their use for prevention of steatohepatosis.

Antioxidant and Hepatoprotective Activity of an Extract from the Overground Parts of Phlomis russeliana Lag. ex Benth

An evaluation of the possible hepatotoxicity/hepatoprotective effects of a defatted extract of the above ground parts of Phlomis russeliana was conducted in vitro and in vivo. The extract was tested in vitro on hepatocytes alone and in a carbon tetrachloride (CCl4)-bioactivation model. The same toxic substance was used for the in vivo evaluation on old Wistar rats. The extract was standardised via high performance liquid chromatography (HPLC) by the quantification of total flavonoids and verbascoside. Gallic acid equivalents were used to express the content of total phenolic compounds. The identification of flavonoids in this species was undertaken for the first time. The extract was not statistically hepatotoxic in vitro on the isolated rat hepatocytes. In the CCl4-induced hepatotoxicity model, the extract had a hepatoprotective effect, which was concentration-dependant (the highest at 50 µg/mL). An in vivo study on old rats confirmed the observed antioxidant and hepatoprotective effects. The histological findings were favourable for the rats, given the extract and CCl4 in combination. They had an unchanged organ structure, which is commensurable with these animals, treated with a combination of CCl4 and silymarin.

Rat Hepatocytes Protect against Lead-Cadmium-Triggered Apoptosis Based on Autophagy Activation.

Lead and cadmium are foodborne contaminants that threaten human and animal health. It is well known that lead and cadmium produce hepatotoxicity; however, defense mechanisms against the co-toxic effects of lead and cadmium remain unknown. We investigated the mechanism of autophagy (defense mechanism) against the co-induced toxicity of lead and cadmium in rat hepatocytes (BRL-3A cells). Cultured rat liver BRL-3A cell lines were co-cultured with 10, 20, 40 μM lead and 2.5, 5, 10 μM cadmium alone and in co-culture for 12 h and exposed to 5 mM 3-Methyladenine (3-MA), 10 μM rapamycin (Rapa), and 50 nM Beclin1 siRNA to induce cellular autophagy. Our results show that treatment of BRL-3A cells with lead and cadmium significantly decreased the cell viability, increased intracellular reactive oxygen species levels, decreased mitochondrial membrane potential levels, and induced apoptosis, which are factors leading to liver injury, and cell damage was exacerbated by co-exposure to lead-cadmium. In addition, the results showed that lead and cadmium co-treatment induced autophagy. We further observed that the suppression of autophagy with 3-MA or Beclin1 siRNA promoted lead-cadmium-induced apoptosis, whereas enhancement of autophagy with Rapa suppressed lead-cadmium-induced apoptosis. These results demonstrated that co-treatment with lead and cadmium induces apoptosis in BRL-3A cells. Interestingly, the activation of autophagy provides cells with a self-protective mechanism against induced apoptosis. This study provides insights into the role of autophagy in lead-cadmium-induced apoptosis, which may be beneficial for the treatment of lead-cadmium-induced liver injury.

NADPH oxidase-generated reactive oxygen species are involved in estradiol 17ß-d-glucuronide-induced cholestasis

The endogenous metabolite of estradiol, estradiol 17β-D-glucuronide (E17G), is considered the main responsible of the intrahepatic cholestasis of pregnancy. E17G alters the activity of canalicular transporters through a signaling pathway-dependent cellular internalization, phenomenon that was attributed to oxidative stress in different cholestatic conditions. However, there are no reports involving oxidative stress in E17G-induced cholestasis, representing this the aim of our work. Using polarized hepatocyte cultures, we showed that antioxidant compounds prevented E17G-induced Mrp2 activity alteration, being this alteration equally prevented by the NADPH oxidase (NOX) inhibitor apocynin. The model antioxidant N-acetyl-cysteine prevented, in isolated and perfused rat livers, E17G-induced impairment of bile flow and Mrp2 activity, thus confirming the participation of reactive oxygen species (ROS) in this cholestasis. In primary cultured hepatocytes, pretreatment with specific inhibitors of ERK1/2 and p38MAPK impeded E17G-induced ROS production; contrarily, NOX inhibition did not affect ERK1/2 and p38MAPK phosphorylation. Both, knockdown of p47phox by siRNA and preincubation with apocynin in sandwich-cultured rat hepatocytes significantly prevented E17G-induced internalization of Mrp2, suggesting a crucial role for NOX in this phenomenon. Concluding, E17G-induced cholestasis is partially mediated by NOX-generated ROS through internalization of canalicular transporters like Mrp2, being ERK1/2 and p38MAPK necessary for NOX activation.

Influence of dark deprivation on the ultrastructure and mitochondrial apparatus of rat hepatocytes

Background
 Melatonin (MT) is a hormone with a wide range of biological activities. The diversity of biological regulatory effects inherent in MT involves this hormone in the formation of adaptive reactions and in the pathogenesis of various diseases. А decrease оf MT secretion due to exposure to light at night is observed in a significant proportion of people. A number of previous studies have shown that melatonin deficiency, causes significant changes in the structure of the liver of laboratory animals. The state of ultrastructural features of hepatocytes, and in particular their mitochondria, under conditions of dark deprivation remains poorly understood.
 Aim of study
 To study the ultrastructural features of liver hepatocytes of male Wistar rats under conditions of 21-day dark deprivation.
 Materials and methods
 The study was performed on 40 male Wistar rats, divided into 2 groups. Group 1 was kept under a fixed light regime. Group 2 was kept under dark deprivation conditions. Liver samples, were analyzed using a transmission electron microscope. Micromorphometric methods were used to assess the mitochondrial apparatus of hepatocytes. Statistical processing of the results were performed in the GraphPad Prism v8.41 program (USA).
 Results
 In hepatocytes of rats of II group, dark deprivation causes a transformation in the shape of the nuclei, accompanied by swelling of the cytoplasm and the presence of a significant number of lipid-containing vacuoles. Mitochondria are characterized by pronounced hyperplasia, size polymorphism, high electron density, and disordered cristae orientation. In the cytoplasm, the phenomenon of shedding of ribosomes from the endoplasmic reticulum is observed. The number of glycogen granules is significantly reduced. The studied micromorphometric parameters of mitochondria are significantly reduced relative to the control.
 Conclusion
 The study suggests that melatonin deficiency, resulting from dark deprivation, leads to a number of significant ultrastructural changes in hepatocytes, especially their mitochondrial apparatus.

Overexpression of Slc22a18 facilitates fat accumulation in mice

We previously reported that solute carrier family 22 member 18 (Slc22a18) regulates lipid accumulation in 3T3-L1 adipocytes. Here, we provide additional evidence derived from experiments with adenoviral vector expression and genetic manipulation of mice. In primary cultured rat hepatocytes, adenoviral overexpression of mouse Slc22a18 increased triglyceride accumulation and triglyceride synthetic activity, which was decreased in an adenoviral knockdown experiment. Adenoviral overexpression of mouse Slc22a18 in vivo caused massive fatty liver in mice, even under normal dietary conditions. Conversely, adenoviral knockdown of mouse Slc22a18 reduced hepatic lipid accumulation induced by a high-glucose and high-sucrose diet. We created Slc22a18 knockout mice, which grew normally and showed no obvious spontaneous phenotypes. However, compared with control littermates, the knockout mice exhibited decreased hepatic triglyceride content under refeeding conditions, significantly reduced epididymal fat mass, and tended to have lower liver weight in conjunction with leptin deficiency. Finally, we created transgenic mice overexpressing rat Slc22a18 in an adipose-specific manner, which had increased body weight and epididymal fat mass primarily because of increased adipocyte cell volume. In these transgenic mice, a positive correlation was observed between adiposity and the expression levels of the rat Slc22a18 transgene. Taken together, these results indicate that Slc22a18 has positive effects on lipid accumulation in vivo.

Antagonizing Activin A/p15INK4b Signaling as Therapeutic Strategy for Liver Disease.

Activin A is involved in the pathogenesis of human liver diseases, but its therapeutic targeting is not fully explored. Here, we tested the effect of novel, highly specific small-molecule-based activin A antagonists (NUCC-474/555) in improving liver regeneration following partial hepatectomy and halting fibrosis progression in models of chronic liver diseases (CLDs). Cell toxicity of antagonists was determined in rat hepatocytes and Huh-7 cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay. Hepatocytes and hepatic stellate cells (HSCs) were treated with activin A and NUCC-555 and analyzed by reverse transcription-polymerase chain reaction and immunohistochemistry. Partial hepatectomized Fisher (F)344 rats were treated with NUCC-555, and bromodeoxyuridine (BrdU) incorporation was determined at 18/24/36/120/240 h. NUCC-555 was administered into thioacetamide- or carbon tetrachloride-treated F344 rats or C57BL/6 mice, and the fibrosis progression was studied. NUCC-474 showed higher cytotoxicity in cultured hepatic cells; therefore, NUCC-555 was used in subsequent studies. Activin A-stimulated overexpression of cell cycle-/senescence-related genes (e.g., p15INK4b, DEC1, Glb1) was near-completely reversed by NUCC-555 in hepatocytes. Activin A-mediated HSC activation was blocked by NUCC-555. In partial hepatectomized rats, antagonizing activin A signaling resulted in a 1.9-fold and 2.3-fold increase in BrdU+ cells at 18 and 24 h, respectively. Administration of NUCC-555 in rats and mice with progressing fibrosis significantly reduced collagen accumulation (7.9-fold), HSC activation indicated by reduced alpha smooth muscle actin+ and vimentin+ cells, and serum aminotransferase activity. Our studies demonstrate that activin A antagonist NUCC-555 promotes liver regeneration and halts fibrosis progression in CLD models, suggesting that blocking activin A signaling may represent a new approach to treating people with CLD.

Investigation of in vitro biliary excretion using the co-culture systems with fresh rat hepatocytes and rat clips-derived bile ducts

Investigation of in vitro biliary excretion using the co-culture systems with fresh rat hepatocytes and rat clips-derived bile ducts

Effect of High-Intensity Interval Training on TCF7L2 Gene Expression in Hepatocytes of Obese Rats


 
 
 Objective: Hepatic glucose release is greatly increased in the presence of obesity and related diseases. The research objective was to explore the impact of high intensity interval training (HIIT) on TCF7L2 gene expression in hepatocytes of obese rats.
 Materials and Methods: Out of 21 male Wistar rats aged 10 weeks years (220±10 g), obesity was induced in 14 rats by 8-week high-fat diet. The rats were then divided into normal (n=7), obese control (n=7), and HIIT obese (n=7) groups. Rats in the HIIT group completed 8 weeks of HIIT/5 days weekly, whereas the other groups were inactive. After intervention, TCF7L2 gene expression in hepatocytes, insulin resistance and glucose compared using ANOVA /Tukey’s post hoc test between groups by SPSS-22.
 Results: Obesity induction led to a significant decrease in TCF7L2 gene expression (P: 0.011) and an increase in blood glucose (P: 0.009) and insulin resistance (P: 0.019) compared with the normal group (P< 0.001). On the other hand, interval training led to a significant increase in TCF7L2 gene expression (P: 0.029) and a decrease in blood glucose (P< 0.001) and insulin resistance (P< 0.001) in the obese group compared with the control group.
 Conclusion: The observed enhancement in fasting blood glucose levels among obese rats could be linked to increased TCF7L2 gene expression in liver cells, which appears to be a response to interval training intervention. Nevertheless, understanding the main mechanisms responsible for observed changes requires further studies in this field.
 
 

In Silico and Chromatographic Methods for Analysis of Biotransformation of Prospective Neuroprotective Pyrrole-Based Hydrazone in Isolated Rat Hepatocytes.

In the current study, chromatographic and in silico techniques were applied to investigate the biotransformation of ethyl 5-(4-bromophenyl)-1-(2-(2-(2-hydroxybenzylidene) hydrazinyl)-2-oxoethyl)-2-methyl-1H-pyrrole-3-carboxylate (11b) in hepatocytic media. The initial chromatographic procedure was based on the employment of the conventional octadecyl stationary phase method for estimation of the chemical stability. Subsequently, a novel and rapid chromatographic approach based on a phenyl-hexyl column was developed, aiming to separate the possible metabolites. Both methods were performed on a Dionex 3000 ThermoScientific (ACM 2, Sofia, Bulgaria) device equipped with a diode array detector set up at 272 and 279 nm for analytes detection. An acetonitrile: phosphate buffer of pH 3.5: methanol (17:30:53 v/v/v) was eluted isocratically as a mobile phase with a 1 mL/min flow rate. A preliminary purification from the biological media was achieved by protein precipitation with methanol. A validation procedure was carried out, where the method was found to correspond to all ICH (Q2) and M10 set criteria. Additionally, an in silico-based approach with the online server BioTransformer 3.0 was applied in an attempt to predict the possible metabolites of the title compound 11b. It was hypothesized that four CYP450 isoforms (1A2, 2C9, 3A4, and 2C8) were involved in the phase I metabolism, resulting in the formation of 12 metabolites. Moreover, docking studies were conducted to evaluate the formation of stable complexes between 11b and the aforementioned isoforms. The obtained data indicated three metabolites as the most probable products, two of which (M9_11b and M10_11b) were synthesized by a classical approach for verification. Finally, liquid chromatography with a mass detector was implemented for comprehensive and summarized analysis, and the obtained results revealed that the metabolism of the 11b proceeds possibly with the formation of glucuronide and glycine conjugate of M11_11b.

Extra-corporeal non-liver transplant therapies for acute liver failure: Focus on plasma exchange and continuous renal replacement therapy.

The acute inflammatory milieu in patients with acute liver failure (ALF) results in 'toxic' blood in these patients. In vitro experiments have shown that the plasma obtained from ALF patients is toxic to rabbit hepatocytes and inhibits regeneration of rat hepatocytes. Treatments such as plasma exchange and continuous renal replacement therapy to cleanse the blood have improved survival in ALF patients. In the liver microcirculation, the exchange of fluid across fenestrae in liver sinusoidal endothelial cells (LSECs) is vital for proper functioning of hepatocytes. Clogging of the liver filter bed by inflammatory debris and cells ('traffic jam hypothesis') impeding blood flow in sinusoids may in turn reduce the exchange of fluid across LSEC fenestrae and cause dysfunction and necrosis of hepatocytes in ALF patients. In mouse model of paracetamol overdose, disturbances in microcirculation in the liver preceded the development of injury and necrosis of hepatocytes. This may represent a reversible pathophysiological mechanism in ALF which may be improved by the anti-inflammatory effect of plasma exchange. Wider access to urgent plasma exchange is a major advantage compared to urgent liver transplantation to treat ALF patients worldwide, especially so in resource constrained settings. Continuous hemo-filtration or dialysis is used toreduce ammonia levels and treat cerebral edema in ALF patients. In this review, we discuss the different modalities to cleanse the blood in ALF patients, with an emphasis on plasma exchange, from a hepatology perspective.

Activity refinement of aryl amino acetamides that target the P. falciparum STAR-related lipid transfer 1 protein

Malaria is a devastating disease that causes significant morbidity worldwide. The development of new antimalarial chemotypes is urgently needed because of the emergence of resistance to frontline therapies. Independent phenotypic screening campaigns against the Plasmodium asexual parasite, including our own, identified the aryl amino acetamide hit scaffold. In a prior study, we identified the STAR-related lipid transfer protein (PfSTART1) as the molecular target of this antimalarial chemotype. In this study, we combined structural elements from the different aryl acetamide hit subtypes and explored the structure-activity relationship. It was shown that the inclusion of an endocyclic nitrogen, to generate the tool compound WJM-715, improved aqueous solubility and modestly improved metabolic stability in rat hepatocytes. Metabolic stability in human liver microsomes remains a challenge for future development of the aryl acetamide class, which was underscored by modest systemic exposure and a short half-life in mice. The optimized aryl acetamide analogs were cross resistant to parasites with mutations in PfSTART1, but not to other drug-resistant mutations, and showed potent binding to recombinant PfSTART1 by biophysical analysis, further supporting PfSTART1 as the likely molecular target. The optimized aryl acetamide analogue, WJM-715 will be a useful tool for further investigating the druggability of PfSTART1 across the lifecycle of the malaria parasite.