Search Results (374)

The COVID-19 pandemic caused more than seven million deaths, mostly via acute respiratory distress syndrome with microvascular thrombosis. Compared to the amount of information about pulmonary pathology, information about COVID-19-induced liver lesions is scarce, especially with regard to the long-term consequences. The aim of our study was to evaluate inflammatory, vascular and fibrotic changes in hepatobiliary tissues of patients with a history of COVID-19 (post-COVID-19 patients). Based on the Knodell score, moderate portal inflammation was observed in 41.2% of post-COVID-19 patients, contrasting with 14.3% of control cases (p = 0.06). Moderate periportal inflammation was present in 26.5% and 7.1% of patients, respectively (p = 0.08). Post-COVID-19 patients showed higher counts of CD3+ lymphocytes (p = 0.02) and lower counts of CD68+ macrophages (p = 0.04), as well as more frequent and extensive regenerative changes in hepatocytes and the biliary epithelium (p = 0.0007). We did not find significant fibrosis or pathological changes in blood vessels, and only mild steatosis was observed in both groups. Full article

Alcoholic liver disease (ALD) is a spectrum of alcohol-induced disorders and represents a major global health challenge. B-cell receptor-associated protein 31 (BAP31) is an endoplasmic reticulum-resident chaperone involved in protein transport, apoptosis, cancer biology, and lipid metabolism. To explore its role in ALD, we used hepatocyte-specific BAP31 knockout mice (BAP31-LKO) and wild-type (WT) littermates exposed to ethanol to assess BAP31′s biochemical and metabolic impact. Following ethanol exposure, BAP31-LKO mice exhibited elevated serum alanine transaminase (23.2%, p < 0.05) and aspartate transaminase (31.4%, p < 0.05) levels compared to WT mice. Increased malondialdehyde (8.5%, p < 0.05) and reduced superoxide dismutase (22.8%, p < 0.05) in BAP31-LKO mice indicate exacerbated liver injury. Furthermore, BAP31 deficiency increased triglyceride (35.7%, p < 0.05) and free fatty acid (16.2%, p < 0.05) accumulation following ethanol treatment, while the expression of fatty acid oxidation-related genes, including Pparα, Cd36, Fatp2, Cpt2, and Acox1, was reduced in BAP31-LKO mice. The mRNA levels of Xbp1, Xbp1s, and Chop, as well as protein levels of p-eIF2α, IRE1α, GRP78, and CHOP, were increased in BAP31-LKO mice compared to WT controls, indicating aggravated ethanol-induced ER stress. Hepatic glycogen content was also reduced in BAP31-LKO mice, along with reduced Ppp1r3c expression, demonstrating impaired glycogen synthesis. Consistently, BAP31 knockdown amplified ethanol-induced lipid accumulation, inflammation, impaired glycogen storage, ER stress, and suppression of Pparα signaling in HepG2 cells. Together, these findings demonstrate that BAP31 deficiency exacerbates ethanol-induced liver steatosis, inflammation, and liver injury by impairing fatty acid oxidation and glycogen synthesis, and by amplifying ER stress responses. Full article

Background: Lipid overaccumulation in the liver predisposes ducks to metabolic disorders. The molecular mechanism of oleic acid (OA)-induced hepatic steatosis in ducks is not fully elucidated. Methods: A cellular model of steatosis was established by treating primary duck hepatocytes with OA. Transcriptome sequencing was performed to identify key signaling pathways and candidate genes. The role of Apolipoprotein A1 (APOA1) was investigated through overexpression and knockdown experiments. Intracellular triglycerides (TGs) were quantified commercially; lipid droplets were visualized by Oil Red O staining. Results: Intracellular TG accumulation was induced by OA treatment in a dose-dependent manner. Through transcriptome analysis, 1045 differentially expressed genes (DEGs) were identified, with APOA1 being recognized as a key candidate within the peroxisome proliferator-activated receptor (PPAR) signaling pathway. The content of TGs and lipid droplets was increased by APOA1 overexpression, whereas these effects were suppressed by APOA1 knockdown. The expression of acetyl-CoA carboxylase alpha (ACACA) and fatty acid synthase (FASN) was upregulated by APOA1. Conversely, the expression of carnitine O-palmitoyltransferase 1 (CPT1), acyl-CoA oxidase 1 (ACOX1), and apolipoprotein B (APOB) was downregulated. Conclusions: This study demonstrates that OA upregulates APOA1, suggesting the involvement of the PPAR pathway and providing a theoretical basis for modulating hepatic fat deposition. Full article

Circadian rhythm disruption induced by exposure to light—excessive in duration and intensity (dark deprivation)—and the impact of hepatotoxins are both significant risk factors for liver pathology. The purpose of this research was to evaluate the potentially synergistic effects of continuous lighting and carbon tetrachloride (CCl₄) toxicity on the structural and functional organization and daily (circadian) rhythmicity of the liver in rats, as well as to look at the corrective capability of exogenous melatonin under such influences. The experiment was conducted on 200 outbred 6-month-old Wistar rat males, which were distributed into five groups, including a control (normal light/dark cycle), dark deprivation (constant light), CCl₄ intoxication, and combined exposure to CCl₄ and dark deprivation with or without melatonin administration (0.3 mg/kg). Histological, immunohistochemical (Ki-67, Per2, and Bmal1), biochemical, and ELISA methods were used. Circadian rhythms were analyzed using cosinor. It was shown that dark deprivation and CCl₄ intoxication act synergistically, potentiating liver damage. The most severe necrosis (54.17 ± 9.13%), steatosis (57.85 ± 12.14%), and suppression of regenerative potential (decreased proportion of binucleated hepatocytes to 2.17 ± 0.21%) were observed in the group with combined exposure. This correlated with a substantial decline in melatonin content in blood plasma (7.85 ± 2.1 pg/mL) and a profound disruption in circadian rhythms. Administration of exogenous melatonin exerted pronounced hepatoprotective and chronotropic effects: it significantly reduced pathological changes (necrosis reduced to 16.35 ± 6.17%), stimulated regeneration (binucleated hepatocytes increased to 13.57 ± 0.81%), and restored the circadian rhythms of the studied parameters to levels close to those of the control. The key pathogenetic link in the potentiation of CCl₄ hepatotoxicity under dark deprivation is light-induced deficiency of endogenous melatonin. Exogenous melatonin demonstrated high efficacy in correcting both structural and functional damage and liver desynchronosis, confirming its therapeutic potential under conditions of combined exposure to chronodisruptors and toxins. Full article

Chronic binge drinking is common among patients with alcohol-associated steatohepatitis. Therefore, we tested the hypothesis that chronic binge ethanol exposure disrupts mitophagic processing and stimulates release of mitochondrial damage-associated molecular patterns (mtDAMPs), thereby promoting hepatic inflammation and fibrosis after chronic binge ethanol (CBE) exposure in mice using the National Institute of Alcohol Abuse and Alcoholism model. After CBE, hepatic steatosis, liver injury, inflammation, and hepatic stellate cell (HSC) activation occurred. Alda-1, an aldehyde dehydrogenase-2 activator, attenuated these changes. After CBE, mitochondrial depolarization (mtDepo) occurred in ~85% hepatocytes, and mitophagy-associated proteins increased, which Alda-1 blunted. By contrast, transcription factor-EB (master regulator of lysosomal biogenesis) and lysosomal markers decreased, indicating disrupted lysosomal processing. After mitophagy, mitochondrial biogenesis (MB) restores mitochondrial mass and function. After CBE, peroxisome proliferator-activated receptor gamma coactivator-1 alpha (MB regulator), mitochondrial transcription factor-A, oxidative phosphorylation proteins, and fatty acid oxidation all decreased, which Alda-1 largely restored. After CBE, serum mtDAMPs (mitochondrial DNA and cytochrome c) increased 3- to 10-fold. In vitro, mitochondrial DNA stimulated macrophage and HSC activation, which was prevented by toll-like receptor-9 inhibition. In conclusion, CBE increases mtDepo in an acetaldehyde-dependent fashion, leading to mitophagic overburden, disruption of mitochondrial homeostasis, mtDAMP release, and ultimately development of liver inflammation and injury. Full article

Background/Objectives: Type 2 diabetes mellitus (T2DM) is a major metabolic disorder and is frequently accompanied by liver steatosis. Apolipoprotein J (ApoJ) is a glucose-regulated molecular chaperone that has been implicated in hepatic lipid deposition under nutrient overload. This study aimed to investigate the role of hepatocyte-specific ApoJ deletion in hepatic metabolism under diabetic conditions. Methods: A T2DM mouse model with hepatocyte-specific ApoJ knockout (HKO) was established through a high-fat diet combined with streptozotocin injection. Hepatic metabolic profiles were analyzed using untargeted metabolomics with UHPLC–MS/MS. Differential metabolites were subjected to KEGG pathway and Sankey diagram analyses to identify biologically relevant pathways. Results: In total, 140 metabolites showed significant differential abundance in HKO mouse liver, primarily encompassing organic acids and derivatives as well as lipids and lipid-like molecules. KEGG analysis revealed that ApoJ deletion enhanced pathways related to vitamin digestion and absorption, thiamine metabolism, amino acid biosynthesis, lysine degradation, and 2-oxocarboxylic acid metabolism. In contrast, pathways associated with galactose metabolism, cysteine and methionine metabolism, purine metabolism, and the pentose phosphate pathway were suppressed. Sankey diagram analysis further demonstrated that ApoJ deletion markedly reshapes hepatic metabolic networks in T2DM. Conclusions: Given the central role of hepatic dysmetabolism in the pathogenesis of diabetes and its complications, targeting ApoJ may represent a promising therapeutic approach for restoring hepatic metabolic homeostasis and preventing diabetes-associated steatosis. Full article

Background: Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in Western countries, characterized by excessive fat storage in the form of lipid droplets (LDs) in hepatocytes; it is also called Metabolic-Associated Steatotic Liver Disease (MASLD), if coexisting with at least one cardiometabolic risk factor. Bergamot polyphenols (BPF) have been shown to counteract hepatic LD accumulation through potent lipogenesis suppression and associated metabolic benefits in Wistar rats, but their liver-specific anti-lipogenic effects may be species- and strain-dependent. Results and Methods: To address this issue we examined the effect of a cafeteria diet (CAF) and BPF in C3H/HeOuJ mice, which are considered resistant to diet-induced MASLD and fibrosis. Interestingly, a 15-week CAF diet led to a robust LD accumulation, weak portal and focal inflammation, and induced a higher expression of lipogenesis (Acly)- but not fibrosis-related (Col1a) genes in C3H/HeOuJ livers. This was associated with a significant increase in blood glucose, triglycerides, and total cholesterol levels, and a decrease in caecal short-chain fatty acids (SCFAs). Importantly, mice co-treated with BPF showed strongly reduced steatosis compared to CAF mice, lower blood glucose and triglyceride levels, stimulation of hepatic autophagy, and a reduced Acly gene and protein expression, followed by a more than doubled and tripled production of total SCFAs and butyric acid, respectively. Conclusions: In conclusion, while CAF diet supplementation in C3H/HeOuJ mice proves to be a suitable model of MASLD with deficient SCFA production, BPF confirms its potency to prevent murine MASLD by pleiotropic mechanisms, including beneficial effects on SCFA content, hepatic autophagy, and lipogenesis. Full article

Background: Bisphenol A (BPA) is a widespread environmental endocrine disruptor associated with metabolic dysfunction-associated steatotic liver disease (MASLD). However, its short-term effects at low, environmentally relevant concentrations are still poorly understood. Methods: Adult zebrafish were exposed to 5, 20, or 100 µg/L BPA for 48 h, 7, or 14 days in a pilot test. The lowest effective condition (20 µg/L for 7 days) was selected for a complete experiment. Fish were divided into two groups: control and BPA-exposed (n = 50/group). After exposure, livers were collected for histological (HE, Oil Red O, Nile Red) and molecular (RT-qPCR) analyses. Results: Exposure to 20 µg/L BPA for 7 days induced moderate to severe hepatic steatosis, characterized by vacuolization, hepatocyte ballooning, and lipid accumulation. Gene expression analysis showed upregulation of fasn (fatty acid synthase), acc1 (acetyl-CoA carboxylase 1), srebp-1c (sterol regulatory element-binding protein 1c), nfkb (nuclear factor kappa B), il-6 (interleukin-6), gpx1 (glutathione peroxidase 1), sod (superoxide dismutase), cyp1a (cytochrome P450 1A), and cyp2ad2 (cytochrome P450 2AD2), while adipor2 (adiponectin receptor 2) and gpx4 (glutathione peroxidase 4) were downregulated (decreased activity). Conclusions: Short-term exposure to a low, environmentally relevant concentration of BPA was sufficient to trigger hepatic steatosis in zebrafish. These effects were associated with enhanced lipogenesis, inflammation, oxidative imbalance, and altered xenobiotic metabolism, suggesting that even brief, low-dose BPA exposure may contribute to early events in MASLD pathogenesis. Full article

Background/Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a sexually dimorphic condition, with higher prevalence in men than in women. Sex differences in hepatic lipid metabolism and the modulatory role of sex hormones have been described but are still insufficiently understood. The aim of this study was to introduce the variables sex and sex hormones into a human in vitro model of hepatic steatosis. Methods: Primary human hepatocytes (PHHs) were isolated from male and female donors, treated with free fatty acids (FFA) to induce steatosis, and further exposed to physiological concentrations of estrogen, progesterone, or testosterone. Intracellular triacylglyceride (TAG) content, lipid droplet (LD) formation, FFA uptake, and very-low-density lipoprotein (VLDL) excretion were assessed. In parallel, the expression of lipid metabolism-related genes was quantified by qPCR. Results: FFA treatment induced comparable uptake and intracellular TAG storage in both sexes. However, female PHHs secreted approximately twice as many VLDL particles as male cells. Steatosis significantly increased expression of LDLR, CPT2, and PLA1A only in male PHHs. Sex hormones exerted distinct, sex-specific effects: estrogen reduced TAG accumulation in female PHHs; whereas testosterone reduced TAG in male but increased it in female PHHs after prolonged treatment. LD characterization confirmed sex- and hormone-dependent differences in lipid storage patterns. In male PHHs, progesterone promoted lipid storage and increased apoB-100 secretion, accompanied by reduced LDLR and APOA5 expression, and testosterone increased the FFA-mediated CPT2 even further. Conclusions: Sex and sex hormones distinctly shape hepatocellular lipid handling under steatotic conditions. While female PHHs demonstrated greater lipid excretion capacity, male PHHs exhibited stronger transcriptional responses. Sex-specific responses to estrogen and testosterone resembled clinical observations on sex hormone effects. These findings highlight the need to account for sex-specific differences in MASLD pathophysiology and therapeutic strategies. Full article

Toxicant-associated steatohepatitis (TASH) is caused by environmental toxicants rather than metabolic factors; however, its pathogenic mechanisms remain poorly understood. Polychlorinated biphenyl 138 (PCB138), a persistent lipophilic contaminant that bioaccumulates in adipose tissue, may promote TASH through unclear mechanisms. In this study, we investigated whether PCB138 induces liver injury via hepatic iron dysregulation and adipose-liver inflammatory signaling. Male C57BL/6 mice received intraperitoneal PCB138 (1, 5, 10, or 50 mg/kg, four injections over six weeks). HepG2 hepatocytes were treated with PCB138 with or without ferric ammonium citrate (FAC), and PCB138-exposed 3T3-L1 adipocytes were co-cultured with HepG2 cells using a Transwell system. PCB138 dose-dependently increased serum transaminase and hepatic non-heme iron levels, with Hamp upregulation, macrophage infiltration, and fibrosis. In HepG2 cells, PCB138 synergized with FAC to elevate intracellular Fe²⁺, induced Hamp, suppressed Slc40a1, and upregulated inflammatory/profibrotic genes. In Transwell co-cultures, TNF-α, IL-6, and IL-1β from PCB138-exposed adipocytes amplified hepatic iron dysregulation and fibrotic responses. These findings demonstrated that PCB138 induced TASH through hepatic iron dysregulation and adipose-derived inflammatory signaling, independent of steatosis. These results highlighted the iron–adipose axis as a novel mechanistic link between PCB138 exposure and liver injury, offering potential therapeutic targets. Full article

Bisphenol AF (BPAF) exposure is increasingly linked to metabolic disorders, yet the molecular initiating events (MIE) and key events (KE) leading to hepatic steatosis remain unclear. We constructed an adverse outcome pathway (AOP) to mechanistically connect BPAF-triggered macrophage–hepatocyte crosstalk to liver fat accumulation. Male C57BL/6 mice received daily oral gavage of 0, 0.5, 4, or 32 mg kg⁻¹ BPAF for 90 d, and Transwell co-cultures of RAW264.7 macrophages and AML12 hepatocytes were used for in vitro validation. Targeted metabolomics, western blotting, and lipid staining quantified succinate, pathway proteins, and steatosis. BPAF dose-dependently increased serum succinate (BMD = 6901.95 nM) and hepatic triglyceride (TG) (BMD = 874.26 nM). Cryo-EM docking revealed BPAF binding to SUCNR1 at 2.9 Å, disrupting the inactive-state conformation. In co-culture, BPAF-exposed macrophages released succinate that bound hepatocyte SUCNR1, suppressed Akt phosphorylation, and activated JNK. These KEs led to a 40% increase in lipid droplets and elevated TG, total cholesterol (TC), and free fatty acids (FFA) without liver weight gain. We propose the first AOP for BPAF-induced hepatic steatosis: BPAF–SUCNR1 binding (MIE) → macrophage succinate release (KE1) → SUCNR1-mediated Akt inhibition/JNK activation (KE2–4) → hepatic lipid accumulation (KE5) → steatosis (AO). These findings provide mechanistic insight for chemical risk assessment of BPAF and structurally related bisphenols. Full article

The signal transducer and activator of transcription 3 (STAT3) in myeloid cells suppresses proinflammatory cytokine production and reduces collagen deposition. However, its role in methionine- and choline-deficient (MCD) diet-fed mice remains unclear. This study investigates the effects of myeloid-specific STAT3 deficiency on hepatic inflammation and fibrosis in MCD diet-fed mice. Myeloid-specific STAT3 knockout (mSTAT3KO) mice were fed the MCD diet for four weeks to induce metabolic dysfunction-associated steatohepatitis (MASH). MCD diet-fed mice displayed MASH-like pathological phenotypes, including hepatic steatosis, inflammation, and fibrosis. Compared with MCD diet-fed WT mice, mSTAT3KO mice fed the MCD diet exhibited reduced hepatic lipid accumulation but increased fibrosis. Notably, mSTAT3KO mice showed elevated hepatic STAT3 and lipocalin-2 (LCN2) protein levels in hepatocytes. Some proinflammatory cytokines were increased by the MCD diet in mSTAT3KO mice, which also exhibited increased hepatocyte apoptosis. Conversely, MCD diet-induced CD36, perilipin-2, acyl-CoA thioesterase 2, and 4-hydroxynonenal proteins were reduced by mSTAT3KO. Myeloid-specific STAT3 deficiency may induce a compensatory STAT3/LCN2 axis in hepatocytes, thereby exacerbating MASH progression. Full article

The development of hepatic steatosis in geese is a complex, multistage process involving genes related to lipid synthesis, transport, storage, and metabolism. Key genes activated during this process include ME1 (malic enzyme 1), SCD1 (stearoyl-CoA desaturase), ACSL1 (acyl-CoA synthetase long-chain family member 1), and ELOVL6 (elongation of very-long-chain fatty acids protein 6). The expression of these genes varies depending on the tissue, breed, and metabolic context. Geese possess a unique ability to develop hepatic steatosis (fatty liver) without accompanying inflammation or liver damage. This condition typically arises from overfeeding, either through carbohydrates or fats, leading to significant triglyceride accumulation in hepatocytes. Importantly, this state remains reversible and is considered non-pathological. The physiological and molecular changes observed in overfed geese, particularly regarding liver lipid accumulation and serum enzyme activity, closely resemble those found in human non-alcoholic fatty liver disease (NAFLD). This similarity makes geese an excellent biomedical model for studying NAFLD. Overfeeding initiates a cascade of enzymatic reactions that regulate lipid metabolism at the genetic level. These reactions decrease circulating free fatty acids and glucose while promoting triglyceride storage in the liver. The aim of this study is to synthesize current knowledge on the genetic regulation of fatty acid metabolism in geese, highlighting how these genes coordinate the processes of activation, desaturation, synthesis, and elongation during induced steatosis. Moreover, the summarized effects of different diet supplements will enhance goose feeding strategies for foie gras production. Full article

Background: Primary hepatocytes are excellent models for studying liver functions and liver diseases. However, obtaining high yields of viable hepatocytes remains technically challenging, limiting their broader applications. Most conventional methods rely on a two-step collagenase perfusion technique. Despite its widespread use, this approach has several limitations that reduce the success rate of hepatocyte isolation and culture. The procedure involves multiple parameters that are continually being optimized in order to obtain hepatocytes in high yield and quality that can be used to provide insights into their physiology and pathophysiology. Aim: We aimed to enhance the success rate and reproducibility of hepatocyte isolation with high yield, enabling analysis of diverse physiological and pathophysiological aspects of lipid metabolism. It also establishes an in vitro steatosis model for evaluating therapeutic drugs and molecular interventions. Methods: Rat liver was perfused in situ with EDTA buffer followed by collagenase IV. Liver was then isolated, and hepatocytes were mechanically liberated, filtered, and purified through density-gradient centrifugation. Viable cells were cultured at 700,000 or 1 million cells/well for 24 h. The monolayer was incubated in lipogenic media for an additional 24 or 48 h. Hepatocytes were fixed, neutral lipids were stained using Oil Red O, and the stained area was quantified using Image J software version 1.54. Results: Yield of hepatocytes was ~75–90 million cells/liver, with viability of 86–93%. Cells seeded at 700,000 and 1 million cells/well reached confluences of 60% and 80%, respectively, after 24 h. Steatosis was then induced with lipid accumulation reaching 21% of image area after 24 h and 25% after 48 h. Conclusions: The current protocol presents an efficient and highly reproducible method for isolating primary rat hepatocytes in high yield with high viability. Additionally, the protocol provides a foundation for studying the pathophysiology of fatty liver disease. Full article

Background: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) has become a worldwide health concern. Soy protein isolate (SPI) is a plant-derived protein with high nutritional value and has shown promising effects in regulating lipid metabolism and inflammation. Objectives: This study aimed to investigate the effects of an α-subunit-deficient SPI (α-lack-SPI) on MASLD and the underlying molecular mechanisms. Methods: Rats were fed with a high-fat, high-cholesterol diet (HFD) to induce MASLD. Results: The results showed that α-lack-SPI significantly reduced the levels of hepatic TG and TC, serum ALT, AST, TC, and LDL-C, and increased serum HDL-C in rats with HFD-induced MASLD. α-lack-SPI significantly attenuated hepatic steatosis and hepatocyte ballooning revealed by histopathological analysis. Meanwhile, α-lack-SPI markedly downregulated the mRNA expressions of Srebf1, Acaca, Fasn, Pcsk9, and Hmgcr, while significantly upregulating Pparα. Additionally, α-lack-SPI treatment significantly reduced the mRNA expressions of hepatic pro-inflammatory cytokines (Tnf-α, Il-1β, Il6), chemokine (Ccl2), and inflammasome component (Nlrp3), as well as the protein expression of COX-2. Conclusions: In conclusion, α-lack-SPI alleviated MASLD in HFD-fed rats probably via improving hepatic lipid metabolism and mitigating hepatic inflammation. These findings indicate that α-lack-SPI may serve as a promising nutritional intervention for MASLD management. Full article