Lipid Metabolism Research Articles

Cysteine-rich 61 inhibition attenuates hepatic insulin resistance and improves lipid metabolism in high-fat diet fed mice and HepG2 cells.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is strongly associated with insulin resistance development. Hepatic lipid accumulation and inflammation are considered the main drivers of hepatic insulin resistance in MASLD. Cysteine-rich 61 (Cyr61 also called CCN1), a novel secretory matricellular protein, is implicated in liver inflammation, and its role in MASLD is not clearly understood. Therefore, we investigated the role of Cyr61 in hepatic insulin resistance and lipid metabolism as major factors in MASLD pathogenesis. In high-fat diet (HFD)-fed C57BL/6J mice, Cyr61 was downregulated or upregulated via viral transduction. Measurements of glucose homeostasis, histological assessment of liver tissues, and gene expression and signaling pathways of lipogenesis, fatty acid oxidation, and inflammation were performed using liver samples from these mice. Cyr61 levels in HepG2 cells were reduced using RNAi-mediated gene knockdown. Inflammation and insulin resistance were evaluated using real-time polymerase chain reaction and western blotting. HFD/AAV-shCyr61 mice exhibited enhanced glucose tolerance via the protein kinase B pathway, reduced hepatic inflammation, decreased lipogenesis, and increased fatty acid oxidation. Notably, HFD/AAV-shCyr61 mice showed elevated protein expression of sirtuin 6 and phosphorylated-AMP-activated protein kinase. Invitro experiments demonstrated that inhibition of Cyr61 downregulated pro-inflammatory cytokines such as interleukin-1 beta, IL-6, and tumor necrosis factor-alpha via the nuclear factor kappa B/c-Jun N-terminal kinase pathway, and alleviated insulin resistance. Cyr61 affected hepatic inflammation, lipid metabolism, and insulin resistance. Inhibition of Cyr61 reduced inflammation, recovered insulin resistance, and altered lipid metabolism invivo and invitro. Therefore, Cyr61 is a potential therapeutic target in MASLD.

PFHpA alters lipid metabolism and increases the risk of metabolic dysfunction-associated steatotic liver disease (MASLD) in youth—a translational research framework

PFHpA alters lipid metabolism and increases the risk of metabolic dysfunction-associated steatotic liver disease (MASLD) in youth—a translational research framework

PFAS are associated with perturbations of lipid metabolism in adolescents

PFAS are associated with perturbations of lipid metabolism in adolescents

Gut microbiota partially mediates the effects of fine particulate matter on blood lipids metabolism

Gut microbiota partially mediates the effects of fine particulate matter on blood lipids metabolism

Loss of STK11 Suppresses Lipid Metabolism and Attenuates KRAS-Induced Immunogenicity in Patients with Non-Small Cell Lung Cancer.

As many as 30% of non-small cell lung cancer (NSCLC) patients harbor oncogenic KRAS mutations, which lead to extensive remodeling of the tumor immune microenvironment. Though co-mutations in several genes have prognostic relevance in KRAS-mutated patients, their effect on tumor immunogenicity are poorly understood. In the present study, a total of 189 NSCLC patients underwent a standardized analysis including immunohistochemistry, whole exome DNA sequencing, and whole transcriptome RNA sequencing. Patients with activating KRAS mutations demonstrated a significant increase in PD-L1 expression and CD8+ T-cell infiltration. Both were increased in the presence of a co-occurring TP53 mutation and lost with STK11 co-mutation. Subsequent genomic analysis demonstrated that KRAS/TP53 co-mutated tumors had a significant decrease in the expression of glycolysis-associated genes, and increase in several genes involved in lipid metabolism, notably Lipoprotein Lipase (LPL), Low Density Lipoprotein Receptor (LDLR), and LDLRAD4. Conversely, in the immune-excluded KRAS/STK11 co-mutated group, we observed diminished lipid metabolism and no change in anaerobic glycolysis. Interestingly, in patients with low expression of LPL, LDLR, or LDLRAD4, KRAS mutations had no effect on tumor immunogenicity. However, in patients with robust expression of these genes, KRAS mutations were associated with increased immunogenicity and associated with improved overall survival. Our data further suggest that the loss of STK11 may function as a metabolic switch, suppressing lipid metabolism in favor of glycolysis, thereby negating KRAS-induced immunogenicity. Hence, this concept warrants continued exploration, both as a predictive biomarker and potential target for therapy in patients receiving ICI-based immunotherapy.

Combinatorial effect of Apigenin-resveratrol on white adipocyte plasticity and trans-differentiation for activating lipid metabolism.

Inducing browning in white adipocytes has emerged as a promising therapeutic approach for addressing obesity. Bioactive that modulate the WAT microenvironment to induce trans browning in white adipocytes have been explored as a strategy to control unregulated lipid storage. However, relying on a single bioactive for modulating lipid metabolism has proven insufficient in obese individuals during human trials, because these compounds primarily activate a single biochemical pathway in promoting browning. Consequently, there is a growing emphasis on targeting multiple pathways to ensure a safe and effective browning process. The present study investigated the combinatorial effect of bioactives namely Apigenin and Resveratrol for activating multiple pathways for effective trans-browning of white adipocytes. The combination was seen to promote the browning more effectively than the single bioactive, as the combination simultaneously activated multiple signaling pathways to induce angiogenesis-mediated browning in primary white adipocytes isolated from obese mice. Activation of PI3K signaling via estrogen receptor-α-dependent pathway resulted in simultaneous activation of angiogenesis and trans browning in white adipocytes. The study provides valuable insights into the potential use of bioactives in combination with therapeutic intervention to improve the overall health of obese subjects by enhancing lipid metabolism by activating trans-differentiation of white adipocytes.

The Rpfor gene modulates the locomotory activity and host-seeking behaviour of Rhodnius prolixus.

The molecular bases of animal behaviour are intricate due to the pleiotropic nature of behaviour-modulating genes, which are often expressed across multiple tissues. The foraging gene (for) encodes a cGMP-dependent protein kinase (PKG), pivotal in regulating downstream target proteins through phosphorylation. In insects, for has been implicated in various behavioural contexts and physiological processes regarding searching for food. Rhodnius prolixus, a hematophagous bug that transmits Trypanosoma cruzi, the causative agent of Chagas disease, exhibits specific activity patterns associated with its hematophagous behaviour. Our previous work demonstrated a correlation between locomotor activity profiles and the expression of Rpfor, suggesting its involvement in modulating triatomine locomotion. In this study, we investigated the impact of Rpfor knockdown on locomotory activity, host-seeking behaviour, feeding performance and lipid metabolism in R. prolixus nymphs. Using RNA interference, we achieved a significant reduction of Rpfor expression in both the brain and fat body of R. prolixus nymphs. Knocked-down nymphs exhibited diminished non-oriented locomotory activity compared with controls, without altering the characteristic bimodal pattern of activity. Additionally, they displayed an increased tendency to approach a host, suggesting a role for Rpfor in modulating host-seeking behaviour. Feeding performance and lipid metabolism remained unaffected by Rpfor knockdown. Our findings underscore the multifaceted role of Rpfor in modulating locomotor activity and host-seeking behaviour in R. prolixus nymphs, shedding light on the molecular mechanisms underlying their hematophagous behaviour and potential implications for disease transmission. Further research is necessary to elucidate the intricate interplay between Rpfor expression, behaviour and physiological processes in triatomine bugs.

Multi-omic analysis of Huntington’s disease reveals a compensatory astrocyte state

The mechanisms underlying the selective regional vulnerability to neurodegeneration in Huntington’s disease (HD) have not been fully defined. To explore the role of astrocytes in this phenomenon, we used single-nucleus and bulk RNAseq, lipidomics, HTT gene CAG repeat-length measurements, and multiplexed immunofluorescence on HD and control post-mortem brains. We identified genes that correlated with CAG repeat length, which were enriched in astrocyte genes, and lipidomic signatures that implicated poly-unsaturated fatty acids in sensitizing neurons to cell death. Because astrocytes play essential roles in lipid metabolism, we explored the heterogeneity of astrocytic states in both protoplasmic and fibrous-like (CD44+) astrocytes. Significantly, one protoplasmic astrocyte state showed high levels of metallothioneins and was correlated with the selective vulnerability of distinct striatal neuronal populations. When modeled in vitro, this state improved the viability of HD-patient-derived spiny projection neurons. Our findings uncover key roles of astrocytic states in protecting against neurodegeneration in HD.

Curcumin, a bioactive compound of Turmeric (Curcuma longa) and its derivatives as α-amylase and α-glucosidase inhibitors.

Diabetes mellitus (DM) is a long-term metabolic disease characterised by a controlled metabolism of fat, carbohydrates, and proteins. In recent decades, it has grown into a significant global public health issue. According to the International Diabetes Federation, there were 425 million DM globally in 2017, and the number might be increased to 629 million by 2045 (a global 48% increase). Approximately 4.2 million deaths globally attributed to DM occur before the age of 60. The existing class of anti-diabetic medications is limited by side effects, which has led to the hunt for novel inhibitors that specifically target the α-amylase and α-glucosidase enzymes. Curcumin is a small-molecular-weight compound found in the roots of the Curcuma longa L (C. longa). plant, which has been used for culinary, medicinal, and other purposes throughout Asia for thousands of years. Curcumin has potent anti-inflammatory, anti-cancer, anti-angiogenic, antispasmodic, antibacterial, and anti-parasitic qualities. Even though the potential of curcumin to cure DM has been well investigated, its low solubility, rapid metabolism, and short plasma half-life have limited its application in DM. Therefore, the objectives of this review were to review the chemical composition of C. longa, the structure of curcumin, the degradation of curcumin, and the effects of curcumin derivatives on anti-diabetic properties against α-amylase and α-glucosidase enzymes. The results showed that C. longa contains carbohydrates, moisture, protein, fat, minerals, volatiles, fibre, and curcuminoids. Among the curcuminoids, curcumin is 60-70% present in C. longa. Moreover, curcumin and its derivatives have a lot of potential for treating DM, which was highlighted in this review. This review emphasises the several biological applications of curcumin, which collectively establish the foundation for its anti-diabetic characteristics. Considering these results, curcumin derivatives may be considered as potential agents in the pharmacotherapeutic management of patients with DM.

Cold shock treatment alleviates pitting in sweet cherry fruit by enhancing antioxidant enzymes activity and regulating membrane lipid metabolism.

In order to comprehend the regulatory mechanisms that result in the alleviation of sweet cherry pitting disorder through cold shock (0 °C ice-water mixture for 10 min), an investigation was conducted into the impacts of cold shock treatment (CST) on membrane lipid metabolism, antioxidant enzyme activity, as well as pitting of cold-stored sweet cherry fruit. CST significantly inhibited the increase in pitting incidence, pitting index, and decay incidence. The CST treatment provided greater titratable acidity, firmness as well as total content of soluble solids. The use of CST prevented the build-up of superoxide anions, hydrogen peroxide, malondialdehyde, and reduced permeability of cell membranes. When in contrast to control group, the CST also raised the expression levels along with activity of the antioxidant enzymes ascorbate peroxidase (APX), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT). Furthermore, CST reduced the amount of fruit cell membrane peroxidation, suppressed the activity of phospholipase and lipoxygenase, postponed the rise in saturated fatty acids (SFAs) and decrease in unsaturated fatty acids (USFAs), ultimately keeping a high ratio of USFAs to SFAs. CST can alleviating pitting disorder in sweet cherry fruit via preventing peroxidation of membrane lipid and elevating the antioxidant enzymes activity. © 2024 Society of Chemical Industry.

Proviral role of ATG2 autophagy related protein in tomato bushy stunt virus replication through bulk phospholipid transfer into the viral replication organelle.

Subversion of cellular membranes and membrane proliferation are used by positive-strand RNA viruses to build viral replication organelles (VROs) that support virus replication. The biogenesis of the membranous VROs requires major changes in lipid metabolism and lipid transfer in infected cells. In this work, we show that tomato bushy stunt virus (TBSV) hijacks Atg2 autophagy related protein with bulk lipid transfer activity into VROs via interaction with TBSV p33 replication protein. Deletion of Atg2 in yeast and knockdown of Atg2 in Nicotiana benthamiana resulted in decreased TBSV replication. We found that subversion of Atg2 by TBSV was important to enrich VRO membranes with phosphatidylethanolamine (PE), phosphatidylserine (PS) and PI(3)P phosphoinositide. Interestingly, inhibition of authophagy did not affect efficient recruitment of Atg2 into VROs and over-expression of Atg2 enhanced TBSV replication, indicating autophagy-independent subversion of Atg2 by TBSV. These findings suggest that the pro-viral function of Atg2 lipid transfer protein is in VRO membrane proliferation. In addition, we find that Atg2 interacting partner Atg9 with membrane lipid scramblase activity is also co-opted for tombusvirus replication. Altogether, subversion of Atg2 bridge-type lipid transfer protein provides a new mechanism for tombusviruses to greatly expand VRO membranes to support robust viral replication.

Rosiglitazone attenuates Acute Kidney Injury from hepatic ischemia-reperfusion in mice by inhibiting arachidonic acid metabolism through the PPAR-γ/NF-κB pathway.

Acute Kidney Injury (AKI), a prevalent complication of Liver Transplantation (LT) that occurs during the perioperative period has been established to profoundly impact the prognosis of transplant recipients. This study aimed to investigate the mechanism of the hepatic IRI-induced AKI and to identify potential therapeutic targets for treating this condition and improving the prognosis of LT patients. An integrated transcriptomics and proteomics approach was employed to investigate transcriptional and proteomic alterations in hepatic IRI-induced AKI and the hypoxia-reoxygenation (H/R) model using TCMK-1 cells and the hepatic IRI-induced AKI mouse model using male C57BL/6J mice were employed to elucidate the underlying mechanisms. Hematoxylin-eosin staining, reverse transcription quantitative polymerase chain reaction, enzyme-linked immunosorbent assay and Western blot were used to assess the effect of Rosiglitazone(RGZ) on hepatic IRI-induced AKI in vitro and in vivo. According to the results, 322 genes and 128 proteins were differentially expressed between the sham and AKI groups. Furthermore, Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomics (KEGG) pathway analyses revealed significant enrichment in pathways related to amino acid and lipid metabolism. Additionally, the Protein-Protein Interaction (PPI) network analysis of the kidney tissues obtained from a hepatic IRI-induced AKI mouse model highlighted arachidonic acid metabolism as the most prominent pathway. Animal and cellular analyses further revealed that RGZ, a PPAR-γ agonist, could inhibit the expression of the PPAR-γ/NF-κB signaling pathway-associated proteins in in vitro and in vivo. These findings collectively suggest that RGZ ameliorates hepatic IRI-induced AKI via PPAR-γ/NF-κB signaling pathway modulation, highlighting PPAR-γ as a crucial therapeutic target for AKI prevention post-LT.

Selection and gene duplication associated with high-elevation diversification in Pristimantis, the largest terrestrial vertebrate genus.

The genus Pristimantis diversified in the tropical Andes mountains and is the most speciose genus of terrestrial vertebrates. Pristimantis are notable among frogs in that they thrive at high elevations (>2000 m) and are direct developers without a tadpole stage. Despite their ecological significance, little is known about the genetic and physiological traits enabling their success. We conducted transcriptomic analysis on seven Pristimantis species sampled across elevations in the Ecuadorean Andes to explore three hypotheses for their success: (1) unique genes are under selection relative to all other frogs, (2) common selection occurs across all direct developers, or (3) common selection occurs across all high-elevation frog clades. Comparative analysis with 34 frog species revealed unique positive selection in Pristimantis genes related to aerobic respiration, hemostasis, signaling, cellular transportation of proteins and ions, and immunity. Additionally, we detected positive selection across all direct developers for genes associated with oxygenase activity and metal ion binding. While many genes under selection in Pristimantis were not positively selected in other high-elevation frog species, we identified some shared genes and pathways linked to lipid metabolism, innate immunity, and cellular redox processes. We observed more positive selection in duplicated versus single copy genes, while relaxed purifying selection was prevalent in single-copy genes. Notably, copy number of an innate immunity complement gene was positively correlated with Pristimantis species elevation. Our findings contribute novel insights into the genetic basis of adaptation in Pristimantis and provide a foundation for future studies on the evolutionary mechanisms leading to direct development and coping with high elevations.

Glycosphingolipid synthesis mediates immune evasion in KRAS-driven cancer.

Cancer cells frequently alter their lipids to grow and adapt to their environment1-3. Despite the critical functions of lipid metabolism in membrane physiology, signalling and energy production, how specific lipids contribute to tumorigenesis remains incompletely understood. Here, using functional genomics and lipidomic approaches, we identified de novo sphingolipid synthesis as an essential pathway for cancer immune evasion. Synthesis of sphingolipids is surprisingly dispensable for cancer cell proliferation in culture or in immunodeficient mice but required for tumour growth in multiple syngeneic models. Blocking sphingolipid production in cancer cells enhances the anti-proliferative effects of natural killer and CD8+ T cells partly via interferon-γ (IFNγ) signalling. Mechanistically, depletion of glycosphingolipids increases surface levels of IFNγ receptor subunit 1 (IFNGR1), which mediates IFNγ-induced growth arrest and pro-inflammatory signalling. Finally, pharmacological inhibition of glycosphingolipid synthesis synergizes with checkpoint blockade therapy to enhance anti-tumour immune response. Altogether, our work identifies glycosphingolipids as necessary and limiting metabolites for cancer immune evasion.

Glutamine withdrawal leads to the preferential activation of lipid metabolism in metastatic colorectal cancer

IntroductionGlutamine is a non-essential amino acid that is critical for cell growth. However, the differential metabolism of l-glutamine in metastatic versus primary colorectal cancer (CRC) has not been evaluated adequately. Materials and methodsDifferential expression of glutamine-related genes was determined in primary versus metastatic CRC. Univariate Cox regression and hierarchical clustering were used to generate a gene signature for prognostication. Untargeted metabolomics and 18O based fluxomics were used to identify differential metabolite levels and energy turnover in the paired primary (SW480) and metastatic (SW620) CRC cells. Western blot and qRT-PCR were used to validate differential gene expression. Subcellular localization of E-cadherin was determined by immunocytochemistry. Lipid droplets were visualized with Nile Red. ResultsThe GO term “Glutamine metabolism” was significantly enriched in metastatic versus primary tumors. Supporting this, SW620 cells showed decreased membrane localization of E-cadherin and increased motility upon l-Glutamine withdrawal. A glutamine related signature associated with worse prognosis was identified and validated in multiple datasets. A fluxomics assay revealed a slower TCA cycle in SW480 and SW620 cells upon l-Glutamine withdrawal. SW620 cells, however, could maintain high ATP levels. Untargeted metabolomics indicated the preferential metabolism of fatty acids in SW620 but not SW480 cells. Lipids were mainly obtained from the environment rather than by de novo synthesis. ConclusionsMetastatic CRC cells can display aberrant glutamine metabolism. We show for the first time that upon l-glutamine withdrawal, SW620 (but not SW480) cells were metabolically plastic and could metabolize lipids for survival and cellular motility.

The role of lycopene in alleviating nanoplastic-induced liver inflammation and steatosis: Insights from gut microbiota remodeling

Nanoplastics (NPs) are emerging pollutants that are widespread in food and drinking water and present a serious danger to the health of animals and humans. Therefore, it is increasingly important to dissect their targeted toxicity mechanism and explore how to mitigate their damaging effects on the organism. Lycopene (LYC)possesses anti-inflammatory, antioxidant, and lipid metabolism– and intestinal microbiota–regulating properties. The research sought to assess the defensive properties of LYC in preventing liver lipid metabolism disorder in mice induced by chronic exposure to nanoparticles. The results indicated that LYC treatment significantly decreased the accumulation of tissue NPs, promoted the excretion of fecal NPs, remodeled intestinal flora, alleviated intestinal injury, decreased circulating lipopolysaccharide production, inhibited the liver TLR4/NF-κB pathway, and ultimately attenuated NPs-induced liver inflammation and steatosis in mice. Interestingly, ablation of the gut microbiota by antibiotic treatment reversed, to some extent, the protective effects of LYC on the NPs-induced disturbances in liver function and lipid metabolism. The fecal transplantation experiment showed that the mice transplanted with microbiota from the NPs + LYC mice had similar phenotypes to those of donor mice, including alleviated liver injury and lipid metabolism disorder. In conclusion, LYC treatment ameliorates liver damage and lipid metabolism disorder caused by NPs, possibly through the modulation of the gut microbiota/liver TLR4/NF-κB signaling axis. This supports LYC as a potential dietary therapy for treating liver steatosis caused by NPs.

ANGPTL4 suppresses clear cell renal cell carcinoma via inhibition of lysosomal acid lipase.

Renal cell carcinoma (RCC), the most common form of kidney cancer, is a heterogeneous disease with clear cell RCC (ccRCC) being the most prevalent and aggressive subtype. While most ccRCC tumors have elevated expression of angiopoietin-like 4 (ANGPTL4), in our study we identified a significant subset of patients whose cancers show no increase in ANGPTL4 expression. These patients have a worse prognosis compared to the patients with high expression of ANGPTL4. These ANGPTL4-low cancers are characterized by the increased frequency of wild-type Von Hippel-Lindau (wt VHL), a gene that is commonly mutated in ccRCC, and an enrichment for genes associated with lipid metabolism. Using RCC tumor models with wild type VHL, we demonstrate that ANGPTL4 behaves as a tumor suppressor. The loss of ANGPTL4 in ccRCC cell lines results in increased tumor growth and colony formation in a lysosomal acid lipase (LAL)-dependent manner, a phenotype rescued by the expression of N-terminus ANGPTL4. At the mechanistic level, the loss of ANGPTL4 increases lysosomal acid lipase activity in ccRCC cells. This data suggests that ANGPTL4 enacts its tumor-suppressive effects in ccRCC by regulating LAL activity. Importantly, the identified patient cohort with low ANGPTL4 expression may exhibit increased reliance on lipid metabolism, which can be a point of target for future therapy.

Synthesis and preclinical testing of a selective beta-subtype agonist of thyroid hormone receptor ZTA-261

BackgroundThyroid hormones (TH) regulate the basal metabolic rate through their receptors THRα and THRβ. TH activates lipid metabolism via THRβ, however, an excess amount of TH can lead to tachycardia, bone loss, and muscle wasting through THRα. In recent years, TH analogs that selectively bind to THRβ have gained attention as new agents for treating dyslipidemia and obesity, which continue to pose major challenges to public health worldwide.MethodsWe developed a TH analog, ZTA-261, by modifying the existing THRβ-selective agonists GC-1 and GC-24. To determine the THRβ-selectivity of ZTA-261, an in vitro radiolabeled TH displacement assay was conducted. ZTA-261 was intraperitoneally injected into a mouse model of high-fat diet-induced obesity, and its effectiveness in reducing body weight and visceral fat, and improving lipid metabolism was assessed. In addition, its toxicity in the liver, heart, and bone was evaluated.ResultsZTA-261 is more selective towards THRβ than GC-1. Although ZTA-261 is less effective in reducing body weight and visceral fat than GC-1, it is as effective as GC-1 in reducing the levels of serum and liver lipids. These effects are mediated by the same pathway as that of T3, a natural TH, as evidenced by similar changes in the expression of TH-induced and lipid metabolism-related genes. The bone, cardiac, and hepatotoxicity of ZTA-261 are significantly lower than those of GC-1.ConclusionsZTA-261, a highly selective and less toxic THRβ agonist, has the potential to be used as a drug for treating diseases related to lipid metabolism.

Composition, Bioactivities, Microbiome, Safety Concerns, and Impact of Essential Oils on the Health Status of Domestic Animals

Essential oils (EOs) are highly concentrated and volatile blends of nonpolar substances that are derived from aromatic plant components and comprise terpenes, terpenoids, and phenylpropanoids, exhibiting diverse biological and pharmacological properties. The burgeoning pet industry is interested in EOs as a potential solution for common health issues in domestic animals, particularly in addressing antimicrobial resistance. The present literature review summarizes the composition, properties, benefits, safety considerations, and effects of EOs on domestic animals. The applications of EOs range from antimicrobial effects to antioxidant, anti-inflammatory, and anticancer activities, etc. The chemical constituents of EOs, exemplified by eucalyptus EO and rosemary EO, highlight their distinct aromatic profiles and potential benefits. Nevertheless, understanding the chemical makeup of EOs is fundamental to assessing their potential impacts on biological systems. The gut microbiota plays a crucial role in regulating various metabolic processes in the host, including energy homeostasis, glucose metabolism, and lipid metabolism. Safety considerations, including potential toxicity risk awareness, are essential when incorporating EOs into animal care routines. The feed additives incorporating EOs have shown promise in influencing gut microbiota balance, reducing inflammation, and acting as antioxidants. However, considering the potential risks associated with high doses or multiple administrations, cautious application is paramount. Preliminary studies suggest low toxicity levels, but further research is required to evaluate the safety of EOs. Though studies have reported the beneficial effects of EOs on pets and animals, further research is needed to validate the findings in real-world conditions. The paper also discussed the regulatory considerations and future perspectives on applying EOs in veterinary medicine.

Estrogenic Responsiveness of Brown Trout Primary Hepatocyte Spheroids to Environmental Levels of 17α-Ethinylestradiol

Three-dimensional (3D) fish hepatocyte cultures are promising alternative models for replicating in vivo data. Few studies have attempted to characterise the structure and function of fish 3D liver models and illustrate their applicability. This study aimed to further characterise a previously established spheroid model obtained from juvenile brown trout (Salmo trutta) primary hepatocytes under estrogenic stimulation. The spheroids were exposed for six days to environmentally relevant concentrations of 17α-ethinylestradiol—EE2 (1–100 ng/L). The mRNA levels of peroxisome (catalase—Cat and urate oxidase—Uox), lipid metabolism (acyl-CoA long chain synthetase 1—Acsl1, apolipoprotein AI—ApoAI, and fatty acid binding protein 1—Fabp1), and estrogen-related (estrogen receptor α—ERα, estrogen receptor β—ERβ, vitellogenin A—VtgA, zona pellucida glycoprotein 2.5—ZP2.5, and zona pellucida glycoprotein 3a.2—ZP3a.2) target genes were evaluated by quantitative real-time polymerase chain reaction. Immunohistochemistry was used to assess Vtg and ZP protein expressions. At the highest EE2 concentration, VtgA and ZP2.5 genes were significantly upregulated. The remaining target genes were not significantly altered by EE2. Vtg and ZP immunostaining was consistently increased in spheroids exposed to 50 and 100 ng/L of EE2, whereas lower EE2 levels resulted in a weaker signal. EE2 did not induce significant changes in the spheroids’ viability and morphological parameters. This study identified EE2 effects at environmentally relevant doses in trout liver spheroids, indicating its usefulness as a proxy for in vivo impacts of xenoestrogens.