Sex-dependent effects of the uncompetitive N-methyl-D-aspartate receptor antagonist REL-1017 in G93A-SOD1 amyotrophic lateral sclerosis mice

Introduction

The pathogenesis of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease caused by the demise of motor neurons has been linked to excitotoxicity caused by excessive calcium influx via N-methyl-D-aspartate receptors (NMDARs), suggesting that uncompetitive NMDAR antagonism could be a strategy to attenuate motor neuron degeneration. REL-1017, the dextro-isomer of racemic methadone, is a low-affinity uncompetitive NMDAR antagonist. Importantly, in humans REL-1017 has shown excellent tolerability in clinical trials for major depression.

Methods

Here, we tested if REL-1017 improves the disease phenotypes in the G93A SOD1 mouse, a well-established model of familial ALS, by examining survival and motor functions, as well as the expression of genes and proteins involved in neuroplasticity.

Results

We found a sex-dependent effect of REL-1017 in G93A SOD1 mice. A delay of ALS symptom onset, assessed as 10%-decrease of body weight (p < 0.01 vs. control untreated mice) and an extension of lifespan (p < 0.001 vs. control untreated mice) was observed in male G93A SOD1 mice. Female G93A SOD1 mice treated with REL-1017 showed an improvement of muscle strength (p < 0.01 vs. control untreated mice). Both males and females treated with REL-1017 showed a decrease in hind limb clasping. Sex-dependent effects of REL-1017 were also detected in molecular markers of neuronal plasticity (PSD95 and SYN1) in the spinal cord and in the GluN1 NMDAR subunit in quadricep muscles.

Conclusion

In conclusion, this study provides preclinical in vivo evidence supporting the clinical evaluation of REL-1017 in ALS.

Tyrosol attenuates NASH features by reprogramming the hepatic immune milieu

Nonalcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease, and no drugs have been approved for its therapy. Among plant-derived molecules, phenolic compounds of extra virgin olive oil like tyrosol (Tyr) had demonstrated multiple beneficial actions for liver health, including the modulation of inflammation in fibrosis. This study aims at assessing the protective effect and mechanism of Tyr in invitro and in vivo models of NASH, with a focus on the hepatic immune microenvironment and extrahepatic manifestations. The effect of Tyr was evaluated in cellular models of NASH, obtained by co-culturing palmitic and oleic acid-treated HepG2 cells with THP1-derived M1 macrophages and LX2 cells, and in a mouse model of NASH induced by a high fructose-high fat diet combined to CCl4 treatment. In vitro Tyr reduced fatty acid (FA) accumulation in HepG2 cells and displayed a beneficial effect on LX2 activation and macrophage differentiation. In vivo, beside reducing steatosis and fibrosis in NASH animals, Tyr prevented inflammation, as demonstrated by the reduction of hepatic inflammatory foci, and immune cells like CD86+ macrophages (p < 0.05), CD4+ (p < 0.05) and T helper effector CD4+ FoxP3- CD62L-lymphocytes (p < 0.05). Also, the prooxidant enzyme NOX1 and the mRNA expression of TGF-β1 and IL6 (p < 0.05) were reduced by Tyr. Notably, in Tyr-treated animals, a significant increase of CD4+ FoxP3+ Treg cells (p < 0.05) was observed, involved in regenerative pathways. Moreover, Tyr attenuated the fatigue and anxious behavior observed in NASH mice. In conclusion, Tyr effectively reduced NASH-related steatosis, fibrosis, oxidative stress, and inflammation, displaying a beneficial effect on the hepatic immune infiltrate, indicating its possible development as a therapeutic agent for NASH due to its multifaceted mechanism.

Are Gender Differences Important for Autoimmune Liver Diseases?

Gender Medicine has had an enormous expansion over the last ten years. Autoimmune liver diseases include several conditions, i.e., autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and conditions involving the liver or biliary tree overlapping with AIH, as well as IgG4-related disease. However, little is known about the impact of sex in the pathogenesis and natural history of these conditions. The purpose of this review is to provide an update of the gender disparities among the autoimmune liver diseases by reviewing the data published from 1999 to 2023. The epidemiology of these diseases has been changing over the last years, due to the amelioration of knowledge in their diagnosis, pathogenesis, and treatment. The clinical data collected so far support the existence of sex differences in the natural history of autoimmune liver diseases. Notably, their history could be longer than that which is now known, with problems being initiated even at a pediatric age. Moreover, gender disparity has been observed during the onset of complications related to end-stage liver disease, including cancer incidence. However, there is still an important debate among researchers about the impact of sex and the pathogenesis of these conditions. With this review, we would like to emphasize the urgency of basic science and clinical research to increase our understanding of the sex differences in autoimmune liver diseases.

Insights into Hepatocellular Carcinoma: From Pathophysiology to Novel Therapies

Hepatocellular carcinoma (HCC), the most common primary liver cancer, accounts for 830,180 related deaths worldwide in 2020, according to GLOBOCAN, representing the fourth leading cause of cancer-related death, with a five-year survival rate of about 18% for advanced stage, and the second leading cause in men of cancer-related mortality worldwide [...].

Adipocyte Precursor-Derived NRG1 Promotes Resistance to FGFR Inhibition in Urothelial Carcinoma

Aberrations of the fibroblast growth factor receptor (FGFR) family members are frequently observed in metastatic urothelial cancer (mUC), and blocking the FGF/FGFR signaling axis is used as a targeted therapeutic strategy for treating patients. Erdafitinib is a pan-FGFR inhibitor, which has recently been approved by the FDA for mUC with FGFR2/3 alterations. Although mUC patients show initial response to erdafitinib, acquired resistance rapidly develops. Here, we found that adipocyte precursors promoted resistance to erdafitinib in FGFR-dependent bladder and lung cancer in a paracrine manner. Moreover, neuregulin 1 (NRG1) secreted from adipocyte precursors was a mediator of erdafitinib resistance by activating human epidermal growth factor receptor 3 (ERBB3; also known as HER3) signaling, and knockdown of NRG1 in adipocyte precursors abrogated the conferred paracrine resistance. NRG1 expression was significantly downregulated in terminally differentiated adipocytes compared with their progenitors. Pharmacologic inhibition of the NRG1/HER3 axis using pertuzumab reversed erdafitinib resistance in tumor cells in vitro and prolonged survival of mice bearing bladder cancer xenografts in vivo. Remarkably, data from single-cell RNA sequencing revealed that NRG1 was enriched in platelet-derived growth factor receptor-A (PDGFRA) expressing inflammatory cancer-associated fibroblasts, which is also expressed on adipocyte precursors. Together, this work reveals a paracrine mechanism of anti-FGFR resistance in bladder cancer, and potentially other cancers, that is amenable to inhibition using available targeted therapies.

SIGNIFICANCE

Acquired resistance to FGFR inhibition can be rapidly promoted by paracrine activation of the NRG1/HER3 axis mediated by adipocyte precursors and can be overcome by the combination of pertuzumab and erdafitinib treatment. See related commentary by Kolonin and Anastassiou, p. 648.

Current Perspectives on the Molecular and Clinical Relationships between Primary Biliary Cholangitis and Hepatocellular Carcinoma

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterised by the immune-mediated destruction of small and medium intrahepatic bile ducts, with variable outcomes and progression. This review summarises the state of the art regarding the risk of neoplastic progression in PBC patients, with a particular focus on the molecular alterations present in PBC and in hepatocellular carcinoma (HCC), which is the most frequent liver cancer in these patients. Major risk factors are male gender, viral infections, e.g., HBV and HCV, non-response to UDCA, and high alcohol intake, as well as some metabolic-associated factors. Overall, HCC development is significantly more frequent in patients with advanced histological stages, being related to liver cirrhosis. It seems to be of fundamental importance to unravel eventual dysfunctional molecular pathways in PBC patients that may be used as biomarkers for HCC development. In the near future, this will possibly take advantage of artificial intelligence-designed algorithms.

Targeting the Adipose Tissue-Liver-Gut Microbiota Crosstalk to Cure MASLD

The gut microbiota is a complex system, playing a peculiar role in regulating innate and systemic immunity. Increasing evidence links dysfunctional gut microbiota to metabolic dysfunction-associated steatotic liver disease (MASLD) due to the activation of multiple pathways in the gut and in the liver, including those mediated by Toll-like receptors (TLRs), that sustain hepatic inflammation. Thus, many efforts have been made to unravel the role of microbiota-associated dysfunction in MASLD, with the final aim of finding novel strategies to improve liver steatosis and function. Moreover, recent evidence underlines the role of adipose tissue in sustaining hepatic inflammation during MASLD development. In this review, we focus on the recently discovered strategies proposed to improve the alteration of gut microbiota observed in MASLD patients, with a particular insight into those known to modulate gut microbiota-associated dysfunction and to affect the complex crosstalk between the gut, the adipose tissue, and the liver.

Sex Drives Functional Changes in the Progression and Regression of Liver Fibrosis

Liver fibrosis is a common and reversible feature of liver damage associated with many chronic liver diseases, and its onset is influenced by sex. In this study, we investigated the mechanisms of liver fibrosis and regeneration, focusing on understanding the mechanistic gaps between females and males. We injected increasing doses of carbon tetrachloride into female and male mice and maintained them for a washout period of eight weeks to allow for liver regeneration. We found that male mice were more prone to developing severe liver fibrosis as a consequence of early chronic liver damage, supported by the recruitment of a large number of Ly6Chigh MoMφs and neutrophils. Although prolonged liver damage exacerbated the fibrosis in mice of both sexes, activated HSCs and Ly6Chigh MoMφs were more numerous and active in the livers of female mice than those of male mice. After eight weeks of washout, only fibrotic females reported no activated HSCs, and a phenotype switching of Ly6Chigh MoMφs to anti-fibrogenic Ly6Clow MoMφs. The early stages of liver fibrosis mostly affected males rather than females, while long-term chronic liver damage was not influenced by sex, at least for liver fibrosis. Liver repair and regeneration were more efficient in females than in males.

Anti-HER2 Super Stealth Immunoliposomes for Targeted-Chemotherapy

Liposomes play an important role in the field of drug delivery by virtue of their biocompatibility and versatility as carriers. Stealth liposomes, obtained by surface decoration with hydrophilic polyethylene glycol (PEG) molecules, represent an important turning point in liposome technology, leading to significant improvements in the pharmacokinetic profile compared to naked liposomes. Nevertheless, the generation of effective targeted liposomes-a central issue for cancer therapy-has faced several difficulties and clinical phase failures. Active targeting remains a challenge for liposomes. In this direction, a new Super Stealth Immunoliposomes (SSIL2) composed of a PEG-bi-phospholipids derivative is designed that stabilizes the polymer shielding over the liposomes. Furthermore, its counterpart, conjugated to the fragment antigen-binding of trastuzumab (Fab'TRZ -PEG-bi-phospholipids), is firmly anchored on the liposomes surface and correctly orients outward the targeting moiety. Throughout this study, the performances of SSIL2 are evaluated and compared to classic stealth liposomes and stealth immunoliposomes in vitro in a panel of cell lines and in vivo studies in zebrafish larvae and rodent models. Overall, SSIL2 shows superior in vitro and in vivo outcomes, both in terms of safety and anticancer efficacy, thus representing a step forward in targeted cancer therapy, and valuable for future development.

Primary biliary cholangitis: primary autoimmune disease or primary secretory defect

INTRODUCTION

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease characterized by the immune-mediated destruction of small and medium intrahepatic bile ducts, involving predominantly females. PBC has long been described as an autoimmune liver disease, also because it is very often associated with many autoimmune conditions. More recently, another pathogenic mechanism exploring the damage of cholangiocytes has been hypothesized, i.e. a defect in the biliary umbrella which is physiologically responsible for the exchange of the ions Cl- and HCO3- and maintains the integrity of glycocalyx. To provide a state-of-the-art analysis of this topic, a systematic review of literature in PubMed, Scopus, and Science Direct was conducted (inclusive dates: 1986-2023).

AREA COVERED

Although the etiology remains unknown, pathogenesis consists of a complex immune-mediated process resulting from a genetic susceptibility. PBC can be triggered by an immune-mediated response to an autoantigen, which leads to a progressive destruction of bile ducts and eventually to a progressive fibrosis with cirrhosis. The defect in the 'bicarbonate umbrella' acts as a protection against the toxic hydrophobic bile acids, leading to a toxic composition of bile.

EXPERT OPINION

This review offers a summary of the current knowledge about the pathogenesis of PBC, indicating that this is probably based on the mutual relationship between the immune insult and the unbalanced secretory mechanisms.

Toward a New Era in the Management of Hepatocellular Carcinoma: Novel Perspectives on Therapeutic Options and Biomarkers

Liver cancer remains a global health challenge and its incidence is growing worldwide [...].

Tumor Mutational Burden for Predicting Prognosis and Therapy Outcome of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), the primary hepatic malignancy, represents the second-highest cause of cancer-related death worldwide. Many efforts have been devoted to finding novel biomarkers for predicting both patients' survival and the outcome of pharmacological treatments, with a particular focus on immunotherapy. In this regard, recent studies have focused on unravelling the role of tumor mutational burden (TMB), i.e., the total number of mutations per coding area of a tumor genome, to ascertain whether it can be considered a reliable biomarker to be used either for the stratification of HCC patients in subgroups with different responsiveness to immunotherapy, or for the prediction of disease progression, particularly in relation to the different HCC etiologies. In this review, we summarize the recent advances on the study of TMB and TMB-related biomarkers in the HCC landscape, focusing on their feasibility as guides for therapy decisions and/or predictors of clinical outcome.

The phenolic compounds tyrosol and hydroxytyrosol counteract liver fibrogenesis via the transcriptional modulation of NADPH oxidases and oxidative stress-related miRNAs

Liver fibrosis is the result of a chronic pathological condition caused by the activation of hepatic stellate cells (HSCs), which induces the excessive deposition of extracellular matrix. Fibrogenesis is sustained by an exaggerated production of reactive oxidative species (ROS) by NADPH oxidases (NOXs), which are overactivated in hepatic inflammation. In this study, we investigated the antifibrotic properties of two phenolic compounds of natural origin, tyrosol (Tyr) and hydroxytyrosol (HTyr), known for their antioxidant and anti-inflammatory effects. We assessed Tyr and HTyr antifibrotic and antioxidant activity both in vitro, by a co-culture of LX2, HepG2 and THP1-derived Mϕ macrophages, set up to simulate the hepatic microenvironment, and in vivo, in a mouse model of liver fibrosis obtained by carbon tetrachloride treatment. We evaluated the mRNA and protein expression of profibrotic and oxidative markers (α-SMA, COL1A1, NOX1/4) by qPCR and/or immunocytochemistry or immunohistochemistry. The expression of selected miRNAs in mouse livers were measured by qPCR. Tyr and HTyr reduces fibrogenesis in vitro and in vivo, by downregulating all fibrotic markers. Notably, they also modulated oxidative stress by restoring the physiological levels of NOX1 and NOX4. In vivo, this effect was accompanied by a transcriptional regulation of inflammatory genes and of 2 miRNAs involved in the control of oxidative stress damage (miR-181-5p and miR-29b-3p). In conclusion, Tyr and HTyr exert antifibrotic and anti-inflammatory effects in preclinical in vitro and in vivo models of liver fibrosis, by modulating hepatic oxidative stress, representing promising candidates for further development.

Improved Trimethylangelicin Analogs for Cystic Fibrosis: Design, Synthesis and Preliminary Screening

A small library of new angelicin derivatives was designed and synthesized with the aim of bypassing the side effects of trimethylangelicin (TMA), a promising agent for the treatment of cystic fibrosis. To prevent photoreactions with DNA, hindered substituents were inserted at the 4 and/or 6 positions. Unlike the parent TMA, none of the new derivatives exhibited significant cytotoxicity or mutagenic effects. Among the synthesized compounds, the 4-phenylderivative 12 and the 6-phenylderivative 25 exerted a promising F508del CFTR rescue ability. On these compounds, preliminary in vivo pharmacokinetic (PK) studies were carried out, evidencing a favorable PK profile per se or after incorporation into lipid formulations. Therefore, the selected compounds are good candidates for future extensive investigation to evaluate and develop novel CFTR correctors based on the angelicin structure.

The Role of Sex in Acute and Chronic Liver Damage

Acute and chronic hepatic damages are caused by xenobiotics or different diseases affecting the liver, characterized by different etiologies and pathological features. It has been demonstrated extensively that liver damage progresses differently in men and women, and some chronic liver diseases show a more favorable prognosis in women than in men. This review aims to update the most recent advances in the comprehension of the molecular basis of the sex difference observed in both acute and chronic liver damage. With this purpose, we report experimental studies on animal models and clinical observations investigating both acute liver failure, e.g., drug-induced liver injury (DILI), and chronic liver diseases, e.g., viral hepatitis, alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), autoimmune liver diseases, and hepatocellular carcinoma (HCC).

A Nutraceutical Formulation Containing Brown Algae Reduces Hepatic Lipid Accumulation by Modulating Lipid Metabolism and Inflammation in Experimental Models of NAFLD and NASH

Recently, some preclinical and clinical studies have demonstrated the ability of brown seaweeds in reducing the risk factors for metabolic syndrome. Here, we analyzed the beneficial effect of a nutraceutical formulation containing a phytocomplex extracted from seaweeds and chromium picolinate in animal models of liver steatosis of differing severities (rats with non-alcoholic fatty liver disease (NAFLD) and its complication, non-alcoholic steatohepatitis (NASH)). This treatment led to a significant drop in hepatic fat deposition in both models (p < 0.01 vs. untreated animals), accompanied by a reduction in plasma inflammatory cytokines, such as interleukin 6, tumor necrosis factor α, and C reactive protein, and myeloperoxidase expression in liver tissue. Furthermore, a modulation of the molecular pathways involved in lipid metabolism and storage was demonstrated, since we observed the significant reduction of the mRNA levels of fatty acid synthase, diacylglycerol acyltransferases, the sterol-binding protein SREBP-1, and the lipid transporter perilipin-2, in both treated NAFLD and NASH rats in comparison to untreated ones. In conclusion, this nutraceutical product was effective in reducing liver steatosis and showed further beneficial effects on hepatic inflammation and glycemic control, which were particularly evident in rats characterized by a more severe condition, thus representing a therapeutic option for the treatment of NAFLD and NASH patients.

In Vitro and In Vivo Sucrosomial® Berberine Activity on Insulin Resistance

Background: Berberine is a natural alkaloid with hypoglycemic properties. However, its therapeutic use is limited by a very low oral bioavailability. Here we developed a new oral formulation of berberine based on Sucrosomial^® technology and tested its effect on insulin resistance. Methods: Sucrosomial^® berberine was first tested in vitro in the hepatoma cell line Huh7 to assess its effect on proteins involved in glucose homeostasis and insulin resistance. The pharmacokinetics and efficacy on insulin resistance were then studied in C57BL/6 mice fed with standard (SD) and high-fat diet (HFD) for 16 weeks and treated daily during the last 8 weeks with oral gavage of Sucrosomial^® berberine or berberine. Results: Sucrosomial^® berberine did not affect Huh7 cell viability at concentrations up to 40 µM. Incubation of Huh7 with 20 µM of Sucrosomial^® and control berberine induced glucokinase (GK) and the phosphorylation of 5′-adenosine monophosphate (AMP)-activated protein kinase (AMPK), both known targets for the control of insulin resistance. In vivo, we observed an 8-fold higher plasma concentration after 3 weeks of oral administration of 50 mg/kg/day of Sucrosomial^® formulation compared to berberine. HFD, compared to SD, induced insulin resistance in mice as determined by oral glucose tolerance test (OGTT). The treatment with a 6.25 mg/kg/daily dose of Sucrosomial^® berberine significantly reduced the area under the curve (AUC) of OGTT (73,103 ± 8645 vs. 58,830 ± 5597 mg/dL × min), while control berberine produced the same effects at 50 mg/Kg/day (51518 ± 1984 mg/dL × min). Under these conditions, the two formulations resulted in similar berberine plasma concentration in mice. Nevertheless, a different tissue distribution of metabolites was observed with a significant accumulation of reduced, demethylated and glucuronide berberine in the brain after the oral administration of the Sucrosomial^® form. Glucuronide berberine plasma concentration was higher with Sucrosomial^® berberine compared to normal berberine. Finally, we observed similar increases of AMPK phosphorylation in the liver in response to the treatment with Sucrosomial^® berberine and berberine. Conclusions: The Sucrosomial^® formulation is an innovative and effective technology to improve berberine gastrointestinal (GI) absorption with proven in vitro and in vivo activity on insulin resistance.

Self-Emulsifying Formulations to Increase the Oral Bioavailability of 4,6,4′-Trimethylangelicin as a Possible Treatment for Cystic Fibrosis

4,6,4′-trimethylangelicin (TMA) is a promising pharmacological option for the treatment of cystic fibrosis (CF) due to its triple-acting behavior toward the function of the CF transmembrane conductance regulator. It is a poorly water-soluble drug, and thus it is a candidate for developing a self-emulsifying formulation (SEDDS). This study aimed to develop a SEDDS to improve the oral bioavailability of TMA. Excipients were selected on the basis of solubility studies. Polyoxyl-35 castor oil (Cremophor® EL) was proposed as surfactant, diethylene glycol-monoethyl ether (Transcutol® HP) as cosolvent, and a mixture of long-chainmono-,di-, and triglycerides (Maisine® CC) or medium-chain triglycerides (LabrafacTM lipophile) as oil phases. Different mixtures were prepared and characterized by measuring the emulsification time, drop size, and polydispersity index to identify the most promising formulation. Two formulations containing 50% surfactant (w/w), 40% cosolvent (w/w), and 10% oil (w/w) (Maisine® CC or LabrafacTM lipophile) were selected. The results showed that both formulations were able to self-emulsify, producing nanoemulsions with a drop size range of 20–25 nm, and in vivo pharmacokinetic studies demonstrated that they were able to significantly increase the oral bioavailability of TMA. In conclusion, SEEDS are useful tools to ameliorate the pharmacokinetic profile of TMA and could represent a strategy to improve the therapeutic management of CF.

Update on the Pharmacological Treatment of Primary Biliary Cholangitis

Ursodeoxycholic acid (UDCA) is the first-line therapy used for the treatment of PBC. In recent years, new pharmacological agents have been proposed for PBC therapy to cure UDCA-non-responders. Obeticholic acid (OCA) is registered in many countries for PBC, and fibrates also seem to be effective in ameliorating biochemistry alteration and symptoms typical of PBC. Moreover, a variety of new agents, acting with different mechanisms of action, are under clinical evaluation for PBC treatment, including PPAR agonists, anti-NOX agents, immunomodulators, and mesenchymal stem cell transplantation. Since an insufficient amount of data is currently available about the effect of these novel approaches on robust clinical endpoints, such as transplant-free survival, their clinical approval needs to be supported by the consistent improvement of these parameters. The intensive research in this field will hopefully lead to a novel treatment landscape for PBC in the near future, with innovative therapies based on the combination of multiple agents acting on different pathogenetic mechanisms.

The Metabolic Activation of Sofosbuvir Is Impaired in an Experimental Model of NAFLD

The effect of liver steatosis on drug metabolism has been investigated in both preclinical and clinical settings, but the findings of these studies are still controversial. We here evaluated the pharmacokinetic profile of the main sofosbuvir metabolite GS-331007 in healthy animals and rats with non-alcoholic fatty liver disease (NAFLD) after the oral administration of a single 400 mg/kg dose of sofosbuvir. The plasma concentration of GS-331007 was evaluated by HPLC-MS. The expression of the two enzymes uridine monophosphate-cytidine monophosphate kinase 1 (UMP-CMPK1), and nucleoside diphosphate kinase (ND-PK), responsible for the formation of the active metabolite GS-331007-TP, were measured by qRT-PCR and Western Blot. We demonstrated that in rats with steatosis, the area under the plasma concentration-vs-time curve (AUC) and the peak plasma concentration (Cmax) of GS-331007 increased significantly whereas the expression of UMP-CMPK was significantly lower than that of healthy animals. The reduction of UMP-CMPK expression suggests an impairment of sofosbuvir activation to GS-331007-TP, giving a possible explanation for the reduction of sofosbuvir efficacy in patients affected by genotype 3 Hepatitis C virus (HCV), which is often associated with liver steatosis. Furthermore, since GS-331007 plasma concentration is altered by steatosis, it can be suggested that the plasma concentration of this metabolite may not be a reliable indicator for exposure-response analysis in patients with NAFLD.

Tyrosine kinase inhibitor prodrug-loaded liposomes for controlled release at tumor microenvironment

Tyrosine kinase inhibitors (TKIs) represent one of the most advanced class of therapeutics for cancer treatment. Most of them are also cytochrome P450 (CYP) inhibitors and/or substrates thereof. Accordingly, their efficacy and/or toxicity can be affected by CYP-mediated metabolism and by metabolism-derived drug-drug interactions. In order to enhance the therapeutic performance of these drugs, we developed a prodrug (Pro962) of our TKI TK962 specifically designed for liposome loading and pH-controlled release in the tumor. A cholesterol moiety was linked to TK962 through pH-sensitive hydrazone bond for anchoring to the liposome phospholipid bilayer to prevent leakage of the prodrug from the nanocarrier. Bioactivity studies performed on isolated target kinases showed that the prodrug maintains only partial activity against them and the release of TK962 is required. Biopharmaceutical studies carried out with prodrug loaded liposomes showed that the prodrug was firmly associated with the vesicles and the drug release was prevented under blood-mimicking conditions. Conversely, conventional liposome loaded with TK962 readily released the drug. Flow cytometric studies showed that liposomes efficiently provided for intracellular prodrug delivery. The use of the hydrazone linker yielded a pH-controlled drug release, which resulted in about 50% drug release at pH 4 and 5 in 2 h. Prodrug, prodrug loaded liposomes and active lead compound have been tested against cancer cell lines in either 2D or 3D models. The liposome formulation showed higher cytotoxicity than the unformulated lead TK962 in both 2D and 3D models. The stability of prodrug, prodrug loaded liposomes and active lead compound in human serum and against human, mouse, and rat microsomes was also assessed, demonstrating that liposome formulations impair the metabolic reactions and protect the loaded compounds from catabolism. The results suggest that the liposomal formulation of pH releasable TKI prodrugs is a promising strategy to improve the metabolic stability, intracellular cancer cell delivery and release, and in turn the efficacy of this class of anticancer drugs.

The Extra Virgin Olive Oil Polyphenol Oleocanthal Exerts Antifibrotic Effects in the Liver

Liver fibrosis, which is the outcome of wound-healing response to chronic liver damage, represents an unmet clinical need. This study evaluated the anti-fibrotic and anti-inflammatory effects of the polyphenol oleocanthal (OC) extracted from extra virgin olive oil (EVOO) by an in vitro/in vivo approach. The hepatic cell lines LX2 and HepG2 were used as in vitro models. The mRNA expression of pro-fibrogenic markers, namely alpha-smooth muscle actin (α-SMA), collagen type I alpha 1 chain (COL1A1), a panel of metalloproteinases (MMP1, MMP2, MMP3, MMP7, MMP9) and vascular endothelial growth factor A (VEGFA) as well as the pro-oxidant genes NADPH oxidases (NOXs) 1 and 4 were evaluated in TGF-β activated LX2 cells by qRT-PCR. α-SMA and COL1A1 protein expression was assessed by immunofluorescence coupled to confocal microscopy. VEGFA release from LX2 was measured by ELISA. We also evaluated the amount of reactive oxygen species (ROS) produced by H₂O₂ activated- HepG2 cells. In vivo, OC was administered daily by oral gavage to Balb/C mice with CCl₄-induced liver fibrosis. In this model, we measured the mRNA hepatic expression of the three pro-inflammatory interleukins (IL) IL6, IL17, IL23, chemokines such as C-C Motif Chemokine Ligand 2 (CCL2) and C-X-C Motif Chemokine Ligand 12 (CXCL12), and selected miRNAs (miR-181-5p, miR-221-3p, miR-29b-3p and miR-101b-3p) by qRT-PCR. We demonstrated that OC significantly downregulated the gene/protein expression of α-SMA, COL1A1, MMP2, MMP3, MMP7 and VEGF as well as the oxidative enzymes NOX1 and 4 in TGFβ1-activated LX2 cells, and reduced the production of ROS by HepG2. In vivo OC, beside causing a significant reduction of fibrosis at histological assessment, counteracted the CCl₄-induced upregulation of pro-fibrotic and inflammatory genes. Moreover, OC upregulated the anti-fibrotic miRNAs (miR-29b-3p and miR-101b-3p) reduced in fibrotic mice, while downregulated the pro-fibrotic miRNAs (miR-221-3p and miR-181-5p), which were dramatically upregulated in fibrotic mice. In conclusion, OC exerts a promising antifibrotic effect via a combined reduction of oxidative stress and inflammation involving putative miRNAs, which in turn reduces hepatic stellate cells activation and liver fibrosis.

Folic Acid-Targeted Paclitaxel-Polymer Conjugates Exert Selective Cytotoxicity and Modulate Invasiveness of Colon Cancer Cells

Although selective tumor delivery of anticancer drugs has been sought by exploiting either passive targeting or by ligand-mediated targeting, a selective anticancer therapy remains an unmet medical need. Despite the advances which have been achieved by nanomedicines, nanosystems such as polymer-drug conjugates still miss the goal of clinical efficacy. In this study, we demonstrated that polymer-drug conjugates require a thoroughly chemical design and the right targeting agent/polymer ratio to be selective and effective towards cancer cells. In particular, two PEG conjugates carrying paclitaxel and targeted with different folic acid (FA)/PEG ratios (one or three) were investigated. The cytotoxicity study in positive (HT-29) and negative (HCT-15) FA receptor (FR)-cell lines demonstrated that the conjugates with one or three FAs were 4- or 28-fold more active in HT-29 cells, respectively. The higher activity of the 3-FA conjugate was confirmed by its strong impact on cell cycle arrest. Furthermore, FA targeting had a clear effect on migration and invasiveness of HT-29 cells, which were significantly reduced by both conjugates. Interestingly, the 3-FA conjugate showed also an improved pharmacokinetic profile in mice. The results of this study indicate that thorough investigations are needed to optimize and tune drug delivery and achieve the desired selectivity and activity towards cancer cells.

REL-1017 (Esmethadone) Increases Circulating BDNF Levels in Healthy Subjects of a Phase 1 Clinical Study

Brain-derived neurotrophic factor (BDNF), a neurotrophin widely expressed in the central nervous system, exhibits important effects on neural plasticity. BDNF has been implicated in the mechanism of action of ketamine, a N-methyl-d-aspartic acid receptor (NMDAR) antagonist with rapid anti-depressant effects in humans. REL-1017 (esmethadone), the d-optical isomer of the racemic mixture d-l-methadone, is devoid of clinically relevant opioid activity at doses expected to exert therapeutic NMDAR antagonistic activity in humans. The present study was conducted to ascertain the effects of oral administration of 25 mg of REL-1017 for 10 days on plasma BDNF in healthy subjects confined to an inpatient unit for a phase 1 clinical trial. We observed an increase in post-treatment BDNF plasma levels compared to pre-treatment levels. Post-treatment, Day 10 BDNF plasma levels ranged from 2 to 17 times pre-treatment levels in the 25 mg REL-1017 treatment group, whereas in the placebo group, BDNF plasma levels remained unchanged (p = 0.028). Diastolic blood pressure decreased significantly in subjects treated with REL-1017, while no effect could be observed in the placebo group. In conclusion, the administration of 25 mg REL-1017 significantly increased BDNF plasma levels and significantly decreased diastolic blood pressure in healthy subjects confined to an inpatient unit for a phase 1 clinical trial.

Refill liquids for electronic cigarettes display peculiar toxicity on human endothelial cells

The electronic cigarettes mimic combustible cigarettes through a heating technology that vaporizes a refill liquid consisting of solvents, flavors, and nicotine. E-cigarettes are sometimes still used as a support for smoking cessation, even if in 2019 an acute lung injury outbreak occurred in the USA, affecting mainly adolescents and young adults, and was correlated to eCigs. Therefore, due to the lack of a definite knowledge about the mechanism(s) of refill liquid toxicity and considering that previous investigations gave controversial results, the aim of the present study was the cytotoxicity assessment of different refill liquids on human endothelial cells, evaluated by means of two different in vitro approaches, i.e. the resazurin and the LDH release assays. Our results clearly demonstrated that different refill liquids (6 samples) display different levels of cytotoxicity in our cellular model, although their cytotoxicity was always lower than that observed for the condensate obtained from traditional cigarettes (3 samples). These results suggest that accurate evaluations should be provided for refill liquids, in particular to correlate their toxicity to their chemical composition, with the final aim of obtaining useful information for the agencies involved in the regulation of their components.

Brown Seaweeds for the Management of Metabolic Syndrome and Associated Diseases

Metabolic syndrome is characterized by the coexistence of different metabolic disorders which increase the risk of developing type 2 diabetes mellitus and cardiovascular diseases. Therefore, metabolic syndrome leads to a reduction in patients' quality of life as well as to an increase in morbidity and mortality. In the last few decades, it has been demonstrated that seaweeds exert multiple beneficial effects by virtue of their micro- and macronutrient content, which could help in the management of cardiovascular and metabolic diseases. This review aims to provide an updated overview on the potential of brown seaweeds for the prevention and management of metabolic syndrome and its associated diseases, based on the most recent evidence obtained from in vitro and in vivo preclinical and clinical studies. Owing to their great potential for health benefits, brown seaweeds are successfully used in some nutraceuticals and functional foods for treating metabolic syndrome comorbidities. However, some issues still need to be tackled and deepened to improve the knowledge of their ADME/Tox profile in humans, in particular by finding validated indexes of their absorption and obtaining reliable information on their efficacy and long-term safety.

Depression and Cognitive Impairment-Extrahepatic Manifestations of NAFLD and NASH

Non-alcoholic fatty liver disease (NAFLD) and its complication non-alcoholic steatohepatitis (NASH) are important causes of liver disease worldwide. Recently, a significant association between these hepatic diseases and different central nervous system (CNS) disorders has been observed in an increasing number of patients. NAFLD-related CNS dysfunctions include cognitive impairment, hippocampal-dependent memory impairment, and mood imbalances (in particular, depression and anxiety). This review aims at summarizing the main correlations observed between NAFLD development and these CNS dysfunctions, focusing on the studies investigating the mechanism(s) involved in this association. Growing evidences point at cerebrovascular alteration, neuroinflammation, and brain insulin resistance as NAFLD/NASH-related CNS manifestations. Since the pharmacological options available for the management of these conditions are still limited, further studies are needed to unravel the mechanism(s) of NAFLD/NASH and their central manifestations and identify effective pharmacological targets.

Cuban Brown Propolis Interferes in the Crosstalk between Colorectal Cancer Cells and M2 Macrophages

Tumor-associated macrophages (TAMs), primarily the M2 phenotype, are involved in the progression and metastasis of colorectal cancer (CRC). Cuban brown propolis (Cp) and its main component Nemorosone (Nem) displays an antiproliferative effect on different cancer cells, including CRC cell lines. However, whether Cp and Nem could exploit its effect on CRC cells by targeting their relationship with TAMs remains to be elucidated. In this study, we differentiated the human monocytic THP-1 cells to M2 macrophages and confirmed this transition by immunofluorescence (IF) staining, qRT-PCR and zymography. An MTT assay was performed to determine the effect of Cp and Nem on the viability of CRC HT-29 cells co-cultured with M2 macrophages. Furthermore, the migration and invasion abilities of HT-29 cells were determined by Transwell assays and the expression levels of epithelial–mesenchymal transition (EMT) markers were analyzed by IF staining. We demonstrated that Cp and Nem reduced the viability of M2 macrophages and, accordingly, the activity of the MMP-9 metalloprotein. Moreover, we demonstrated that M2 macrophages produce soluble factors that positively regulate HT-29 cell growth, migration and invasion. These M2-mediated effects were counteracted by Cp and Nem treatments, which also played a role in regulating the expression of the EMT markers E-cadherin and vimentin. Taken together, our results indicate that Nem contained in Cp interferes in the crosstalk between CRC cells and TAMs, by targeting M2 macrophages.

Fucus vesiculosus and Ascophyllum nodosum Ameliorate Liver Function by Reducing Diet-Induced Steatosis in Rats

The Asian coastal communities have used the brown seaweeds Fucus vesiculosus and Ascophyllum nodosum since ancient times. Recently, some in vitro and in vivo studies have demonstrated their abilities in reducing risk factors for metabolic syndrome. Here, we analyzed the protective effect of a phytocomplex extracted from these seaweeds on the deposition of fat in the liver after the administration of a high-fat diet (HFD) to rats for five weeks. The administration of F. vesiculosus and A. nodosum led to significant reductions in microvescicular steatosis and plasma biochemical and lipid parameters, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total and conjugated bilirubin, and triglycerides. Furthermore, the postprandial glycemic peak was delayed and significantly reduced (p < 0.01) by the algal extract administration. In conclusion, this extract is effective in reducing microvescicular steatosis and improving glycemic control, thereby lowering the risk of nonalcoholic fatty liver disease, obesity, and diabetes, diseases related to the consumption of fat and sugar-enriched diets.

Nemorosone inhibits the proliferation and migration of hepatocellular carcinoma cells

AIMS

In the tumor microenvironment, dysregulated immune cells could promote tumor progression, invasion and metastasis, by establishing a symbiotic relationship with cancer cells. A pivotal role is played by monocyte recruitment and induction of tumor-associated macrophages (TAMs), which provide immunosuppression and tumorigenesis. The effect of nemorosone, an antiproliferative phytocomponent present in Cuban Propolis, on TAM-induced tumor progression remains to be elucidated. Here we investigated the symbiotic relationship between monocytic leukemia THP-1 and hepatocellular carcinoma HepG2 cells, and the role of nemorosone in preventing TAM-induced tumor growth.

MAIN METHODS

Macrophage differentiation induced by HepG2-conditioned medium was assessed by flow cytometry, analysis of secreted molecules and cytokine expression. The effect of nemorosone and/or conditioned THP-1-medium on HepG2 proliferation was evaluated by MTT assay, colony formation, cells cycle and migration assays.

KEY FINDINGS

HepG2 cells induced THP-1 recruitment and differentiation to macrophages. When compared with control THP-1 cells, differentiated THP-1 showed a significant increase of the matrix metalloproteinases MMP-2 and MMP-9 expression (P < 0.01), and slightly induced HepG2 cells growth. This effect was counteracted by nemorosone, which also significantly inhibited colony formation (P < 0.01) and migratory capacity of HepG2 cells, driving a high percentage of cells (80%) to the G0/G1 phase.

SIGNIFICANCE

HepG2-conditioned medium is a suitable model for THP-1 modulation and differentiation. Moreover, nemorosone significantly inhibits the proliferation of HepG2 cells, both in presence and absence of the soluble factors secreted by TAMs. Further studies are needed to elucidate the role of this natural compound in the HCC-TAM relationship.

The Brown Algae Fucus vesiculosus and Ascophyllum nodosum Reduce Metabolic Syndrome Risk Factors: A Clinical Study

Fucus vesiculosus and Ascophyllum nodosum have been traditionally used for the treatment of obesity and several gastrointestinal diseases. We have recently demonstrated that the phytocomplex obtained from these algae (Gdue™) controls postprandial glucose levels in a mouse model of steatohepatitis, a condition often associated with obesity and type 2 diabetes mellitus. We analyzed the effect of Gdue™ on HOMA index, waist circumference, fasting blood glucose and insulin levels in overweight or obese subjects. Waist circumference decreased significantly after 6 months of treatment (112 ± 17 at t0 vs 105 ± 13 cm after 6 months of treatment; p<0.0001). Both blood glucose and insulin levels were significantly reduced after 6 months of treatment with Gdue™ (110 ± 15 at t0 vs 98 ± 15 mg/dL after 6 months for glucose; p<0.0001; 22.6 ± 9.5 at t0 vs 17.8 ± 8.6 μU/mL after 6 months for insulin; p<0.05). Accordingly, HOMA index decreased significantly (6.103 ± 2.548 at t0 vs 4.419 ± 2.382 after 6 months; p<0.01), suggesting an improvement of insulin sensitivity status. This phytocomplex represents a useful dietary supplement for controlling relevant metabolic syndrome risk factors, such as waist circumference, fasting insulin and glucose levels.

Dexamethasone counteracts hepatic inflammation and oxidative stress in cholestatic rats via CAR activation

Glucocorticoids (GCs) are currently used for the therapeutic management of cholestatic diseases, but their use and molecular mechanism remain controversial. The aims of this study were 1) to assess the therapeutic effect of a 2-week treatment with the GC dexamethasone on hepatic damage in bile duct-ligated rats; 2) to investigate its effect on the activation of the nuclear receptors (NRs) pregnane X receptor (PXR), constitutive androstane receptor (CAR) and GC receptor (GR), and NF-kB, as well as on oxidative stress and bile acid (BA) hepatic composition. Cholestasis was induced by ligation of bile duct (BDL animals) in 16 male Wistar-Kyoto rats, and eight of them were daily treated by oral gavage with 0.125 mg/ml/kg DEX for 14 days. Eight Sham-operated rats were used as controls. Severity of cholestasis was assessed histologically and on plasma biochemical parameters. The nuclear expression of NF-kB (p65), GR, PXR and CAR was measured in hepatic tissue by Western Blot. Oxidative stress was evaluated by measuring malondialdehyde, carbonylated proteins, GHS and ROS content in rat livers. LC-MS was used to measure the plasma and liver concentration of 7 BAs. Histological findings and a significant drop in several markers of inflammation (p65 nuclear translocation, mRNA expressions of TNF-α, IL-1β, IL-6) showed that DEX treatment reversed cholestasis-induced inflammation, and similar results have been obtained with oxidative stress markers. The nuclear expression of p65 and CAR were inversely correlated, with the latter increasing significantly after DEX treatment (p<0.01 vs vehicle). Hepatic BA levels tended to drop in the untreated cholestatic rats, whereas they were similar to those of healthy rats in DEX-treated animals. Plasma BAs decreased significantly in DEX-treated animals with respect to untreated cholestatic rats. In conclusion, DEX reduces inflammation and oxidative stress in BDL rats, and probably CAR is responsible for this effect. Therefore, this NR represents a promising pharmacological target for managing cholestatic and inflammatory liver diseases.

Pregnane X receptor and constitutive androstane receptor modulate differently CYP3A-mediated metabolism in early- and late-stage cholestasis

AIM

To ascertain whether cholestasis affects the expression of two CYP3A isoforms (CYP3A1 and CYP3A2) and of pregnane X receptor (PXR) and constitutive androstane receptor (CAR).

METHODS

Cholestasis was induced by bile duct ligation in 16 male Wistar rats; whereas 8 sham-operated rats were used as controls. Severity of cholestasis was assessed on histological examination of liver sections, and serum concentrations of albumin, AST, ALT, GGT, ALPK and bilirubin. Gene and protein expressions of PXR, CAR, CYP3A1 and CYP3A2 were assessed by means of qRT-PCR and Western blot, respectively. Alterations in CYP3A activity were measured by calculating the kinetic parameters of 4-OH and 1’-OH-midazolam hydroxylation, marker reactions for CYP3A enzymes.

RESULTS

The mRNA and protein expression of CYP3A1 increased significantly in mild cholestasis (P < 0.01). At variance, mRNA and protein expression of CYP3A2 didn’t change in mild cholestasis, whereas the expression and activity of both CYP3A1 and CYP3A2 decreased dramatically when cholestasis became severe. Consistently with these observations, the nuclear expression of both PXR and CAR, which was measured because they both translocate into the cell nucleus after their activation, virtually disappeared in the late stage of cholestatic injury, after an initial increase. These results indicate that early- and late-stage cholestasis affects CYP3A-mediated drug metabolism differently, probably as consequence of the different activation of PXR and CAR.

CONCLUSION

Early- and late-stage cholestasis affects CYP3A-mediated drug metabolism differently. PXR and CAR might be targeted therapeutically to promote CYP3A-mediated liver detoxification.

Silybin counteracts doxorubicin resistance by inhibiting GLUT1 expression

Despite significant advances in the diagnosis and treatment of cancer, the development of drug resistance still remains one of the principal causes that hampers the effectiveness of the therapy. Emerging evidences support the idea that the dysregulated metabolism could be related to drug resistance. The major goal of this study was to target cancer metabolic pathways using new pharmacological approaches coming from natural sources in order to possibly prevent or overcome this phenomenon. Firstly, the metabolic profile of human colorectal adenocarcinoma cells sensitive (LoVo WT) and resistant to doxorubicin (LoVo DOX) was delineated demonstrating that resistant cells remodel their metabolism toward a glycolytic phenotype. In particular it was observed that doxorubicin-resistant cancer cells exhibit an increased dependency from glucose for their survival, associated with overexpression of the glycolytic pathway. Moreover, both GLUT1 mRNA and protein expression significantly increased in LoVo DOX cells. Given the results about the metabolic profile, silybin, modulator of GLUTs, was selected as potential candidate to overcome doxorubicin resistance and, intriguingly, data revealed not only that silybin is more active in resistant cells than in wild type cells, but also that the combined treatment with doxorubicin and silybin presents a synergistic effect in LoVo DOX cells. Although many unanswered questions still remain about the molecular mechanism of silybin, these data suggest that targeting GLUTs may be a good strategy to restore doxorubicin sensitivity and elude drug resistance.

Human Adenocarcinoma Cell Line Sensitivity to Essential Oil Phytocomplexes from Pistacia Species: a Multivariate Approach

Principal component analysis (PCA) multivariate analysis was applied to study the cytotoxic activity of essential oils from various species of the Pistacia genus on human tumor cell lines. In particular, the cytotoxic activity of essential oils obtained from P. lentiscus, P. lentiscus var. chia (mastic gum), P. terebinthus, P. vera, and P. integerrima, was screened on three human adenocarcinoma cell lines: MCF-7 (breast), 2008 (ovarian), and LoVo (colon). The results indicate that all the Pistacia phytocomplexes, with the exception of mastic gum oil, induce cytotoxic effects on one or more of the three cell lines. PCA highlighted the presence of different cooperating clusters of bioactive molecules. Cluster variability among species, and even within the same species, could explain some of the differences seen among samples suggesting the presence of both common and species-specific mechanisms. Single molecules from one of the most significant clusters were tested, but only bornyl-acetate presented cytotoxic activity, although at much higher concentrations (IC₅₀ = 138.5 µg/mL) than those present in the essential oils, indicating that understanding of the full biological effect requires a holistic vision of the phytocomplexes with all its constituents.

The Phytocomplex from Fucus vesiculosus and Ascophyllum nodosum Controls Postprandial Plasma Glucose Levels: An In Vitro and In Vivo Study in a Mouse Model of NASH

Edible seaweeds have been consumed by Asian coastal communities since ancient times. Fucus vesiculosus and Ascophyllum nodosum extracts have been traditionally used for the treatment of obesity and several gastrointestinal diseases. We evaluated the ability of extracts obtained from these algae to inhibit the digestive enzymes α-amylase and α-glucosidase in vitro, and control postprandial plasma glucose levels in a mouse model of non-alcoholic steatohepatitis (NASH); a liver disease often preceding the development of Type 2 diabetes (T2DM). This model was obtained by the administration of a high-fat diet. Our results demonstrate that these algae only delayed and reduced the peak of blood glucose (p < 0.05) in mice fed with normal diet, without changing the area under the blood glucose curve (AUC). In the model of NASH, the phytocomplex was able to reduce both the postprandial glycaemic peak, and the AUC. The administration of the extract in a diet particularly rich in fat is associated with a delay in carbohydrate digestion, but also with a decrease in its assimilation. In conclusion, our results indicate that this algal extract may be useful in the control of carbohydrate digestion and absorption. This effect may be therapeutically exploited to prevent the transition of NASH to T2DM.

Differential effect of liver cirrhosis on the pregnane X receptor-mediated induction of CYP3A1 and 3A2 in the rat

Conflicting results have been obtained by clinical studies investigating the effect of liver cirrhosis on enzyme induction. Because ethical concerns do not give consent for methodologically rigorous studies in humans, we addressed this question by examining the effect of the prototypical inducer dexamethasone (DEX) on the pregnane X receptor (PXR)-mediated induction of CYP3A1 and 3A2 in a validated animal model of liver cirrhosis obtained by exposure of rats to carbon tetrachloride. For this purpose, we assessed mRNA levels, protein expressions, and enzymatic activities of both CYP3A enzymes, as well as mRNA and protein expressions of PXR in rat populations rigorously stratified according to the severity of liver insufficiency. Constitutive mRNA and protein expressions of CYP3A1 and CYP3A2 and their basal enzyme activities were not affected by liver dysfunction. DEX treatment markedly increased steady-state mRNA level, protein content, and enzymatic activity of CYP3A1 in healthy and cirrhotic rats, irrespective of the degree of liver dysfunction. On the contrary, the inducing effect of DEX on gene and protein expressions and enzyme activity of CYP3A2 was preserved in moderate liver insufficiency, whereas it was greatly curtailed when liver insufficiency became severe. mRNA and protein expressions of PXR were neither reduced by liver dysfunction nor increased by DEX treatment. These results indicate that even the inducibility of cytochrome P450 isoforms under the transcriptional control of the same nuclear receptor may be differentially affected by cirrhosis and may partly explain why conflicting results were obtained by human studies.

Severe liver cirrhosis markedly reduces AhR-mediated induction of cytochrome P450 in rats by decreasing the transcription of target genes

Although the induction of cytochrome P450 (CYP) has long been investigated in patients with cirrhosis, the question whether liver dysfunction impairs the response to CYP inducers still remains unresolved. Moreover, the mechanism underlying the possible effect of cirrhosis on induction has not been investigated. Since ethical constraints do not permit methodologically rigorous studies in humans, this question was addressed by investigating the effect of the prototypical inducer benzo[a]pyrene (BP) on CYP1A1 and CYP1A2 in cirrhotic rats stratified according to the severity of liver dysfunction. We simultaneously assessed mRNA level, protein expression and enzymatic activity of the CYP1A enzymes, as well as mRNA and protein expressions of the aryl hydrocarbon receptor (AhR), which mediates the BP effect. Basal mRNA and protein expressions of CYP1A1 were virtually absent in both healthy and cirrhotic rats. On the contrary, CYP1A2 mRNA, protein and enzyme activity were constitutively present in healthy rats and decreased significantly as liver function worsened. BP treatment markedly increased the concentrations of mRNA and immunodetectable protein, and the enzymatic activities of both CYP1A enzymes to similar levels in healthy and non-ascitic cirrhotic rats. Induced mRNA levels, protein expressions and enzymatic activities of both CYPs were much lower in ascitic rats and were proportionally reduced. Both constitutive and induced protein expressions of AhR were significantly lower in ascitic than in healthy rats. These results indicate that the inducibility of CYP1A enzymes is well preserved in compensated cirrhosis, whereas it is markedly reduced when liver dysfunction becomes severe. Induction appears to be impaired at the transcriptional level, due to the reduced expression of AhR, which controls the transcription of CYP1A genes.

Severe liver cirrhosis markedly reduces AhR-mediated induction of cytochrome P450 in rats by decreasing the transcription of target genes

Although the induction of cytochrome P450 (CYP) has long been investigated in patients with cirrhosis, the question whether liver dysfunction impairs the response to CYP inducers still remains unresolved. Moreover, the mechanism underlying the possible effect of cirrhosis on induction has not been investigated. Since ethical constraints do not permit methodologically rigorous studies in humans, this question was addressed by investigating the effect of the prototypical inducer benzo[a]pyrene (BP) on CYP1A1 and CYP1A2 in cirrhotic rats stratified according to the severity of liver dysfunction. We simultaneously assessed mRNA level, protein expression and enzymatic activity of the CYP1A enzymes, as well as mRNA and protein expressions of the aryl hydrocarbon receptor (AhR), which mediates the BP effect. Basal mRNA and protein expressions of CYP1A1 were virtually absent in both healthy and cirrhotic rats. On the contrary, CYP1A2 mRNA, protein and enzyme activity were constitutively present in healthy rats and decreased significantly as liver function worsened. BP treatment markedly increased the concentrations of mRNA and immunodetectable protein, and the enzymatic activities of both CYP1A enzymes to similar levels in healthy and non-ascitic cirrhotic rats. Induced mRNA levels, protein expressions and enzymatic activities of both CYPs were much lower in ascitic rats and were proportionally reduced. Both constitutive and induced protein expressions of AhR were significantly lower in ascitic than in healthy rats. These results indicate that the inducibility of CYP1A enzymes is well preserved in compensated cirrhosis, whereas it is markedly reduced when liver dysfunction becomes severe. Induction appears to be impaired at the transcriptional level, due to the reduced expression of AhR, which controls the transcription of CYP1A genes.