GenX analogs exposure induced greater hepatotoxicity than GenX mainly via activation of PPARα pathway while caused hepatomegaly in the absence of PPARα in female mice

Despite their use as substitutes for perfluorooctanoic acid, the potential toxicities of hexafluoropropylene oxide dimer acid (HFPO-DA, commercial name: GenX) and its analogs (PFDMOHxA, PFDMO2HpA, and PFDMO2OA) remain poorly understood. To assess the hepatotoxicity of these chemicals on females, each chemical was orally administered to female C57BL/6 mice at the dosage of 0.5 mg/kg/d for 28 d. The contribution of peroxisome proliferator-activated receptors (PPARα and γ) and other nuclear receptors involving in these toxic effects of GenX and its analogs were identified by employing two PPAR knockout mice (PPARα-/- and PPARγΔHep) in this study. Results showed that the hepatotoxicity of these chemicals increased in the order of GenX < PFDMOHxA < PFDMO2HpA < PFDMO2OA. The increases of relative liver weight and liver injury markers were significantly much lower in PPARα-/- mice than in PPARα+/+ mice after GenX analog exposure, while no significant differences were observed between PPARγΔHep and its corresponding wildtype groups (PPARγF/F mice), indicating that GenX analog induce hepatotoxicity mainly via PPARα instead of PPARγ. The PPARα-dependent complement pathways were inhibited in PFDMO2HpA and PFDMO2OA exposed PPARα+/+ mice, which might be responsible for the observed liver inflammation. In PPARα-/- mice, hepatomegaly and increased liver lipid content were observed in PFDMO2HpA and PFDMO2OA treated groups. The activated pregnane X receptor (PXR) and constitutive activated receptor (CAR) pathways in the liver of PPARα-/- mice, which were highlighted by bioinformatics analysis, provided a reasonable explanation for hepatomegaly in the absence of PPARα. Our results indicate that GenX analogs could induce more serious hepatotoxicity than GenX whether there is a PPARα receptor or not. These chemicals, especially PFDMO2HpA and PFDMO2OA, may not be appropriate PFOA alternatives.

Noninvasive prediction of insufficient biochemical response after ursodeoxycholic acid treatment in patients with primary biliary cholangitis based on pretreatment nonenhanced MRI

OBJECTIVES

To explore the feasibility of pretreatment nonenhanced magnetic resonance imaging (MRI) in predicting insufficient biochemical response to ursodeoxycholic acid (UDCA) in patients with primary biliary cholangitis (PBC).

METHODS

From January 2009 to April 2022, consecutive PBC patients who were treated with UDCA and underwent nonenhanced MRI within 30 days before treatment were retrospectively enrolled. All MR images were independently evaluated by two blinded radiologists. Uni- and multivariable logistic regression analyses were performed to develop a predictive model for 12-month insufficient biochemical response. Model performances were evaluated by computing the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity.

RESULTS

A total of 74 patients (50.6 ± 11.9 years; 62 females) were included. Three pretreatment MRI features, including hepatomegaly (odds ratio [OR]: 4.580; p = 0.011), periportal hyperintensity on T2-weighted imaging (T2WI) (OR: 4.795, p = 0.008), and narrowing of the bile ducts (OR: 3.491; p = 0.027) were associated with 12-month insufficient biochemical response in the multivariable analysis. A predictive model based on the above indicators had an AUC of 0.781, sensitivity of 85.4%, and specificity of 61.5% for predicting insufficient biochemical response.

CONCLUSIONS

A noninvasive model based on three pretreatment MRI features could accurately predict 12-month insufficient biochemical response to UDCA in patients with PBC. Early identification of PBC patients at increased risk for insufficient response can facilitate the timely initiation of additional treatment.

CLINICAL RELEVANCE STATEMENT

A noninvasive predictive model constructed by incorporating three pretreatment MRI features may help identify patients with primary biliary cholangitis at high risk of insufficient biochemical response to ursodeoxycholic acid and facilitate the timely initiation of additional treatment.

KEY POINTS

• Noninvasive imaging features based on nonenhanced pretreatment MRI may predict an insufficient biochemical response to UDCA in PBC patients. • A combined model based on three MRI features (hepatomegaly, periportal hyperintensity on T2-weighted imaging, and narrowing of the bile ducts) further improved the predictive efficacy for an insufficient biochemical response to UDCA in PBC patients, with high sensitivity and specificity. • The nomogram of the combined model showed good calibration and predictive efficacy for an insufficient biochemical response to UDCA in PBC patients. In particular, the calibration curve visualised the clinical applicability of the prediction model.

Peroxisome proliferator-activated receptor α agonist induces mouse hepatomegaly through the spatial hepatocyte enlargement and proliferation

Peroxisome proliferator-activated receptor alpha (PPARα) activation-induced hepatomegaly is accompanied by hepatocyte hypertrophy around the central vein (CV) area and hepatocyte proliferation around the portal vein (PV) area. However, the molecular mechanisms underlying this spatial change of hepatocytes remains unclear. In this study, we examined the characteristics and possible reasons for the zonation distinction of hypertrophy and proliferation during PPARα activation-induced mouse liver enlargement. Mice were injected with corn oil or a typical mouse PPARα agonist WY-14643 (100 mg·kg-1·d-1, i.p.) for 1, 2, 3, 5 or 10 days. At each time point, the mice were sacrificed after the final dose, and liver tissues and serum were harvested for analysis. We showed that PPARα activation induced zonal changes in hepatocyte hypertrophy and proliferation in the mice. In order to determine the zonal expression of proteins related to hepatocyte hypertrophy and proliferation in PPARα-induced liver enlargement, we performed digitonin liver perfusion to separately destroy the hepatocytes around the CV or PV areas, and found that PPARα activation-induced increase magnitude of its downstream targets such as cytochrome P450 (CYP) 4 A and acyl-coenzyme A oxidase 1 (ACOX1) levels around the CV area were higher compared with those around the PV area. Upregulation of proliferation-related proteins such as cell nuclear antigen (PCNA) and cyclin A1 (CCNA1) after WY-14643-induced PPARα activation mainly occurred around the PV area. This study reveals that the zonal expression of PPARα targets and proliferation-related proteins is responsible for the spatial change of hepatocyte hypertrophy and proliferation after PPARα activation. These findings provide a new insight into the understanding of PPARα activation-induced liver enlargement and regeneration.

Long-term treatment with the mPXR agonist PCN promotes hepatomegaly and lipid accumulation without hepatocyte proliferation in mice

Pregnane X receptor (PXR) is highly expressed in the liver and plays a pivotal role in xenobiotic and endobiotic metabolism. We previously reported that PXR activation by its specific mouse agonist pregnenolone 16α-carbonitrile (PCN) significantly induces liver enlargement and lipid accumulation. However, the effect of long-term PCN treatment on PXR and mouse liver is still unknown. This study aimed to explore the influence of long-term administration of PCN on mouse liver and hepatic lipid homeostasis. Male C57BL/6 mice were injected intraperitoneally with PCN (100 mg/kg once a week) for 42 weeks. Serum and liver samples were collected for biochemical and histological analysis. PXR activation was investigated by Western blot. Ultra-high-performance liquid chromatography coupled with electrospray ionization high-resolution mass spectrometry (UHPLC-ESI-HRMS)-based lipidomics analysis was performed to explore the change in different lipid categories. The results showed that long-term treatment with PCN significantly promoted hepatomegaly without hepatocyte proliferation and enlargement. Long-term treatment with PCN did not upregulate PXR target proteins in mice, and there was no significant upregulation of CYP3A11, CYP2B10, UGT1A1, MRP2, or MRP4. Lipidomics analysis showed obvious hepatic lipid accumulation in the PCN-treated mice, and the most significant change was found in triglycerides (TGs). Additionally, long-term treatment with PCN had no risk for carcinogenesis. These findings demonstrated that long-term PCN treatment induces hepatomegaly and lipid accumulation without hepatocyte proliferation or enlargement.

Elemicin exposure induced aberrant lipid metabolism via modulation of gut microbiota in mice

Elemicin (Ele) is a constituent of natural alkenylbenzene present in many foods and herbs. Ele exposure could induce hepatomegaly and hepatosteatosis. However, the role of gut microbiota in Ele-induced hepatotoxicity remains unclear. Here, the mice were treated with 200 mg/kg/day of Ele for 4 weeks with or without depletion of gut microbiota by antibiotics cocktail treatment. The mice treated with Ele showed enlargement of liver and slight hepatosteatosis, accompanied by higher levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG). Ele could also shift the structure of fecal microbiota and increase the richness. Functional prediction of the microbiota revealed the enrichment of non-alcoholic fatty liver disease pathway upon Ele exposure. Compared with control group, Patescibacteria and Epsilonbacteraeota were significantly enriched at the phylum level upon Ele treatment. A total of 20 genera were significant with respect specifically to Ele exposure, including decreased Alistipes and elevated Ruminiclostridium_9 and Gordonibacter. Among them, 13 retained significant associations with ALT and TG by Spearman correlation test, 4 were correlated with AST. Further MaAsLin analysis revealed that ALT was associated with 4 differentially abundant genera, such as Alistipes and Ruminiclostridium_9 and Gordonibacter. In addition, only Alistipes was significantly correlated with serum TG. Intriguingly, depletion of the microbiota significantly attenuated hepatosteatosis, restore increased ALT, AST and TG and inhibit the expression of genes involved in de novo lipogenesis and adipocyte differentiation, such as Fasn, ADIPOQ and leptin. Collectively, depletion of gut microbiota protected against Ele induced aberrant lipid metabolism in mice.

Inhalation exposure to 2-ethyl-1-hexanol causes hepatomegaly and transient lipid accumulation without induction of peroxisome proliferator-activated receptor alpha in mice

2-Ethyl-1-hexanol (2EH) is a volatile organic compound known to cause sick building syndrome. However, 2EH-induced hepatotoxicity has been mainly evaluated in experiments orally administering 2EH as a metabolite of di(2-ethylhexyl) phthalate. To evaluate the hepatotoxicity risk of 2EH as an indoor air pollutant, we exposed 10-wk-old male ICR mice to 2EH by inhalation for 8 h/d, 5 d/wk for 3 months (0, 20, 60, or 150 ppm) or 6 months (0, 0.5, 10, or 100 ppm). In both experiments, relative liver weights significantly increased in the highest exposure groups. The 3-month exposure increased histopathological lipid droplets in the liver in a dose-dependent manner, hepatic triglyceride at all exposure levels, hepatic phospholipid at 150 ppm, and microsomal triglyceride transfer protein at 60 and 150 ppm; however, these changes were not observed following the 6-month of exposure. Following the 3-month exposure, alanine transaminase and peroxisomal bifunctional proteins, known markers of liver injury and peroxisome proliferation, respectively, remained unaltered. Therefore, in the present study, the inhalation concentration range of 2EH induced a toxic hypertrophic change, revealing a limited role of peroxisome proliferator-activated receptor alpha (PPARα). The liver weights may have presumably increased via a mechanism independent of PPARα activation.

Enrichment of progenitor cells by 2-acetylaminofluorene accelerates liver carcinogenesis induced by diethylnitrosamine in vivo

The potential role of hepatocytes versus hepatic progenitor cells (HPC) on the onset and pathogenesis of hepatocellular carcinoma (HCC) has not been fully clarified. Because the administration of 2-acetylaminofluorene (2AAF) followed by a partial hepatectomy, selectively induces the HPC proliferation, we investigated the effects of chronic 2AAF administration on the HCC development caused by the chronic administration of the carcinogen diethylnitrosamine (DEN) for 16 weeks in the rat. DEN + 2AAF protocol impeded weight gain of animals but promoted prominent hepatomegaly and exacerbated liver alterations compared to DEN protocol alone. The tumor areas detected by γ-glutamyl transferase, prostaglandin reductase-1, and glutathione S-transferase Pi-1 liver cancer markers increased up to 80% as early as 12 weeks of treatment, meaning 6 weeks earlier than DEN alone. This protocol also increased the number of Ki67-positive cells and those of CD90 and CK19, two well-known progenitor cell markers. Interestingly, microarray analysis revealed that DEN + 2AAF protocol differentially modified the global gene expression signature and induced the differential expression of 30 genes identified as HPC markers as early as 6 weeks of treatment. In conclusion, 2AAF induces the early appearance of HPC markers and as a result, accelerates the hepatocarcinogenesis induced by DEN in the rat. Thus, since 2AAF simultaneously administrated with DEN enriches HPC during hepatocarcinogenesis, we propose that DEN + 2AAF protocol might be a useful tool to investigate the cellular origin of HCC with progenitor features.

Schisandrol B promotes liver enlargement via activation of PXR and YAP pathways in mice

BACKGROUND

Schisandrol B (SolB) is one of the bioactive components from a traditional Chinese medicine Schisandra chinensis or Schisandra sphenanthera. It has been demonstrated that SolB exerts hepatoprotective effects against drug-induced liver injury and promotes liver regeneration. It was found that SolB can induce hepatomegaly but the involved mechanisms remain unknown.

PURPOSE

This study aimed to explore the mechanisms involved in SolB-induced hepatomegaly.

METHODS

Male C57BL/6 mice were injected intraperitoneally with SolB (100 mg/kg) for 5 days. Serum and liver samples were collected for biochemical and histological analyses. The mechanisms of SolB were investigated by qRT-PCR and western blot analyses, luciferase reporter gene assays and immunofluorescence.

RESULTS

SolB significantly increased hepatocyte size and proliferation, and then promoted liver enlargement without liver injury and inflammation. SolB transactivated human PXR, activated PXR in mice and upregulated hepatic expression of its downstream proteins, such as CYP3A11, CYP2B10 and UGT1A1. SolB also significantly enhanced nuclear translocation of PXR and YAP in human cell lines. YAP signal pathway was activated by SolB in mice.

CONCLUSION

These findings demonstrated that SolB can significantly induce liver enlargement, which is associated with the activation of PXR and YAP pathways.

Hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX) alters maternal and fetal glucose and lipid metabolism and produces neonatal mortality, low birthweight, and hepatomegaly in the Sprague-Dawley rat

Hexafluoropropylene oxide dimer acid (HFPO-DA or GenX) is an industrial replacement for the straight-chain perfluoroalkyl substance (PFAS), perfluorooctanoic acid (PFOA). Previously we reported maternal, fetal, and postnatal effects from gestation day (GD) 14-18 oral dosing in Sprague-Dawley rats. Here, we further evaluated the perinatal toxicity of HFPO-DA by orally dosing rat dams with 1-125 mg/kg/d (n = 4 litters per dose) from GD16-20 and with 10-250 mg/kg/d (n = 5) from GD8 - postnatal day (PND) 2. Effects of GD16-20 dosing were similar to those previously reported for GD14-18 dosing and included increased maternal liver weight, altered maternal serum lipid and thyroid hormone concentrations, and altered expression of peroxisome proliferator-activated receptor (PPAR) pathway genes in maternal and fetal livers. Dosing from GD8-PND2 produced similar effects as well as dose-responsive decreased pup birth weight (≥30 mg/kg), increased neonatal mortality (≥62.5 mg/kg), and increased pup liver weight (≥10 mg/kg). Histopathological evaluation of newborn pup livers indicated a marked reduction in glycogen stores and pups were hypoglycemic at birth. Quantitative gene expression analyses of F1 livers revealed significant alterations in genes related to glucose metabolism at birth and on GD20. Maternal serum and liver HFPO-DA concentrations were similar between dosing intervals, indicating rapid clearance, however dams dosed GD8 - PND2 had greater liver weight and gestational weight gain effects at lower doses than GD16-20 dosing, indicating the importance of exposure duration. Comparison of neonatal mortality dose-response curves between HFPO-DA and previously published perfluorooctane sulfonate (PFOS) data indicated that, based on serum concentration, the potency of these two PFAS are similar in the rat. Overall, HFPO-DA is a developmental toxicant in the rat and the spectrum of adverse effects is consistent with prior PFAS toxicity evaluations, such as PFOS and PFOA.

Chronic exposure to 6:2 chlorinated polyfluorinated ether sulfonate acid (F-53B) induced hepatotoxic effects in adult zebrafish and disrupted the PPAR signaling pathway in their offspring

As a Chinese-specific alternative to perfluorooctane sulfonate (PFOS), 6:2 chlorinated polyfluorinated ether sulfonate (commercial name: F-53B) has been used in the metal plating industry for over 40 years. This prevalence of use has resulted in its subsequent detection within the environment, wildlife, and humans. Despite this, however, its hepatotoxic effects on aquatic organisms remain unclear. Here, we characterized the impacts of long-term F-53B exposure on adult zebrafish liver and their offspring. Results showed that the concentration of F-53B was greater in the F0 liver than that in the gonads and blood. Furthermore, males had significantly higher liver F-53B levels than females. Hepatomegaly and obvious cytoplasmic vacuolation indicated that F-53B exposure induced liver injury. Compared to control, liver triglyceride levels decreased by 30% and 33.5% in the 5 and 50 μg/L-exposed males and 22% in 50 μg/L-exposed females. Liver transcriptome analysis of F0 adult fish found 2175 and 1267 differentially expressed genes (DEGs) in the 5 μg/L-exposed males and females, respectively. Enrichment analyses further demonstrated that the effects of F-53B on hepatic transcripts were sex-dependent. Gene Ontology showed that most DEGs were involved in multicellular organism development in male fish, whereas in female fish, most DEGs were related to metabolic processes and gene expression. qRT-PCR analysis indicated that the PPAR signaling pathway likely contributed to F-53B-induced disruption of lipid metabolism in F0 adult fish. In F1 larvae (5 days post fertilization), the transcription of pparα increased, like that in F0 adult fish, but most target genes showed the opposite expression trends as their parents. Taken together, our research demonstrated chronic F-53B exposure adversely impacts zebrafish liver, with disruption of PPAR signaling pathway dependent on sex and developmental stage.

TCPOBOP-Induced Hepatomegaly and Hepatocyte Proliferation are Attenuated by Combined Disruption of MET and EGFR Signaling

TCPOBOP (1,4-Bis [2-(3,5-Dichloropyridyloxy)] benzene) is a constitutive androstane receptor (CAR) agonist that induces robust hepatocyte proliferation and hepatomegaly without any liver injury or tissue loss. TCPOBOP-induced direct hyperplasia has been considered to be CAR-dependent with no evidence of involvement of cytokines or growth factor signaling. Receptor tyrosine kinases (RTKs), MET and epidermal growth factor receptor (EGFR), are known to play a critical role in liver regeneration after partial hepatectomy, but their role in TCPOBOP-induced direct hyperplasia, not yet explored, is investigated in the current study. Disruption of the RTK-mediated signaling was achieved using MET knockout (KO) mice along with Canertinib treatment for EGFR inhibition. Combined elimination of MET and EGFR signaling [MET KO + EGFR inhibitor (EGFRi)], but not individual disruption, dramatically reduced TCPOBOP-induced hepatomegaly and hepatocyte proliferation. TCPOBOP-driven CAR activation was not altered in [MET KO + EGFRi] mice, as measured by nuclear CAR translocation and analysis of typical CAR target genes. However, TCPOBOP-induced cell cycle activation was impaired in [MET KO + EGFRi] mice due to defective induction of cyclins, which regulate cell cycle initiation and progression. TCPOBOP-driven induction of FOXM1, a key transcriptional regulator of cell cycle progression during TCPOBOP-mediated hepatocyte proliferation, was greatly attenuated in [MET KO + EGFRi] mice. Interestingly, TCPOBOP treatment caused transient decline in hepatocyte nuclear factor 4 alpha expression concomitant to proliferative response; this was not seen in [MET KO + EGFRi] mice. Transcriptomic profiling revealed the vast majority (~40%) of TCPOBOP-dependent genes primarily related to proliferative response, but not to drug metabolism, were differentially expressed in [MET KO + EGFRi] mice. Conclusion: Taken together, combined disruption of EGFR and MET signaling lead to dramatic impairment of TCPOBOP-induced proliferative response without altering CAR activation.

Short-term vitamin E treatment impairs reactive oxygen species signaling required for adipose tissue expansion, resulting in fatty liver and insulin resistance in obese mice

Objectives

The use of antioxidant therapy in the treatment of oxidative stress-related diseases such as cardiovascular disease, diabetes or obesity remains controversial. Our aim is to demonstrate that antioxidant supplementation may promote negative effects if used before the establishment of oxidative stress due to a reduced ROS generation under physiological levels, in a mice model of obesity.

Methods

C57BL/6J mice were fed with a high-fat diet for 14 weeks, with (OE group) or without (O group) vitamin E supplementation.

Results

O mice developed a mild degree of obesity, which was not enough to induce metabolic alterations or oxidative stress. These animals exhibited a healthy expansion of retroperitoneal white adipose tissue (rpWAT) and the liver showed no signs of lipotoxicity. Interestingly, despite achieving a similar body weight, OE mice were insulin resistant. In the rpWAT they presented a reduced generation of ROS, even below physiological levels (C: 1651.0 ± 212.0; O: 3113 ± 284.7; OE: 917.6 ±104.4 RFU/mg protein. C vs OE p< 0.01). ROS decay may impair their action as second messengers, which could account for the reduced adipocyte differentiation, lipid transport and adipogenesis compared to the O group. Together, these processes limited the expansion of this fat pad and as a consequence, lipid flux shifted towards the liver, causing steatosis and hepatomegaly, which may contribute to the marked insulin resistance.

Conclusions

This study provides in vivo evidence for the role of ROS as second messengers in adipogenesis, lipid metabolism and insulin signaling. Reducing ROS generation below physiological levels when the oxidative process has not yet been established may be the cause of the controversial results obtained by antioxidant therapy.

Hepatic tuberculosis: a rare cause of fluorodeoxyglucose hepatic superscan with background suppression on positron emission tomography

Fluorodeoxyglucose (FDG) hepatic superscan refers to the diffuse intense uptake of 18F-FDG in the liver on positron emission tomography (PET), with reduced physiological activity in the brain and heart. The common causes include lymphoma and metastasis. In this case report, we describe the imaging features of tuberculosis as a rare cause of FDG hepatic superscan. PET imaging may be the only clue to a diagnosis of hepatic tuberculosis, as other imaging modalities may demonstrate only nonspecific hepatomegaly. It is important to consider this entity in the differential diagnosis of patients presenting with FDG hepatic superscan and proceed with liver biopsy for a definitive diagnosis.

Propofol infusion syndrome: a structured review of experimental studies and 153 published case reports

INTRODUCTION

Propofol infusion syndrome (PRIS) is a rare, but potentially lethal adverse effect of a commonly used drug. We aimed to review and correlate experimental and clinical data about this syndrome.

METHODS

We searched for all case reports published between 1990 and 2014 and for all experimental studies on PRIS pathophysiology. We analysed the relationship between signs of PRIS and the rate and duration of propofol infusion causing PRIS. By multivariate logistic regression we looked at the risk factors for mortality.

RESULTS

Knowledge about PRIS keeps evolving. Compared to earlier case reports in the literature, recently published cases describe older patients developing PRIS at lower doses of propofol, in whom arrhythmia, hypertriglyceridaemia and fever are less frequently seen, with survival more likely. We found that propofol infusion rate and duration, the presence of traumatic brain injury and fever are factors independently associated with mortality in reported cases of PRIS (area under receiver operator curve = 0.85). Similar patterns of exposure to propofol (in terms of time and concentration) are reported in clinical cases and experimental models of PRIS. Cardiac failure and metabolic acidosis occur early in a dose-dependent manner, while arrhythmia, other electrocardiographic changes and rhabdomyolysis appear more frequently after prolonged propofol infusions, irrespective of dose.

CONCLUSION

PRIS can develop with propofol infusion <4 mg/kg per hour and its diagnosis may be challenging as some of its typical features (hypertriglyceridaemia, fever, hepatomegaly, heart failure) are often (>95 %) missing and others (arrhythmia, electrocardiographic changes) occur late.

c-Myc and transforming growth factor α enhance the development of hepatic lesions due to mutant β-catenin in transgenic mice

Alterations in the Wnt signaling pathway are associated with diverse cancers, including hepatocellular carcinoma (HCC). The development of HCC is thought to be a multistage process in which multiple genetic alterations are necessary. Few studies have assessed the effect of aberrant Wnt signaling activity in association with other molecular alterations in HCC. Here we sought to determine whether co-overexpression of c-Myc or TGFα, 2 signaling molecules known to contribute to HCC development, enhanced the development of hepatic lesions associated with a stabilized β-catenin. The coexpression of mutant β-catenin with either c-Myc or TGFα within hepatocytes increased the severity of hepatic lesions compared with that associated with any of the transgenes expressed individually. The coexpression of mutant β-catenin with c-Myc or TGFα resulted in severe hepatomegaly necessitating the euthanasia of mice by an average of 156 and 128 d, respectively, after the cessation of doxycycline. The expression of mutant β-catenin alone resulted in mild to moderate hepatomegaly that prompted the euthanasia of mice by an average of 75 d after the cessation of doxycycline. Collectively, these findings indicate that coexpression of c-Myc or TGFα delays the onset of endstage hepatic disease yet enhances the severity of hepatic lesions due to mutant β-catenin.

Carbamazepine-induced DRESS syndrome in a child: rapid response to pulsed corticosteroids

DRESS syndrome is an idiosyncratic reaction to drugs, which can occur in both adults and children. To date there is no agreed upon criteria for its diagnosis; there is even less consensus on its management. We report the case of a 14- year-old boy with carbamazepine induced DRESS syndrome, predominantly involving the liver. He responded rapidly to high dose pulsed intravenous corticosteroids.

Long-term bezafibrate treatment improves skin and spleen phenotypes of the mtDNA mutator mouse

Pharmacological agents, such as bezafibrate, that activate peroxisome proliferator-activated receptors (PPARs) and PPAR γ coactivator-1α (PGC-1α) pathways have been shown to improve mitochondrial function and energy metabolism. The mitochondrial DNA (mtDNA) mutator mouse is a mouse model of aging that harbors a proofreading-deficient mtDNA polymerase γ. These mice develop many features of premature aging including hair loss, anemia, osteoporosis, sarcopenia and decreased lifespan. They also have increased mtDNA mutations and marked mitochondrial dysfunction. We found that mutator mice treated with bezafibrate for 8-months had delayed hair loss and improved skin and spleen aging-like phenotypes. Although we observed an increase in markers of fatty acid oxidation in these tissues, we did not detect a generalized increase in mitochondrial markers. On the other hand, there were no improvements in muscle function or lifespan of the mutator mouse, which we attributed to the rodent-specific hepatomegaly associated with fibrate treatment. These results showed that despite its secondary effects in rodent’s liver, bezafibrate was able to improve some of the aging phenotypes in the mutator mouse. Because the associated hepatomegaly is not observed in primates, long-term bezafibrate treatment in humans could have beneficial effects on tissues undergoing chronic bioenergetic-related degeneration.

Aflatoxin exposure may contribute to chronic hepatomegaly in Kenyan school children

BACKGROUND

Presentation with a firm type of chronic hepatomegaly of multifactorial etiology is common among school-age children in sub-Saharan Africa.

OBJECTIVE

Aflatoxin is a liver toxin and carcinogen contaminating staple maize food. In this study we examined its role in chronic hepatomegaly.

METHODS

Plasma samples collected in 2002 and again in 2004 from 218 children attending two schools in neighboring villages were assayed for aflatoxin exposure using the aflatoxin-albumin adduct (AF-alb) biomarker. Data were previously examined for associations among hepatomegaly, malaria, and schistosomiasis.

RESULTS

AF-alb levels were high in children from both schools, but the geometric mean (95% confidence interval) in year 2002 was significantly higher in Matangini [206.5 (175.5, 243.0) pg/mg albumin] than in Yumbuni [73.2 (61.6, 87.0) pg/mg; p < 0.001]. AF-alb levels also were higher in children with firm hepatomegaly [176.6 (129.6, 240.7) pg/mg] than in normal children [79.9 (49.6, 128.7) pg/mg; p = 0.029]. After adjusting for Schistosoma mansoni and Plasmodium infection, we estimated a significant 43% increase in the prevalence of hepatomegaly/hepatosplenomegaly for every natural-log-unit increase in AF-alb. In 2004, AF-alb levels were markedly higher than in 2002 [539.7 (463.3, 628.7) vs. 114.5 (99.7, 131.4) pg/mg; p < 0.001] but with no significant difference between the villages or between hepatomegaly and normal groups [539.7 (436.7, 666.9) vs. 512.6 (297.3, 883.8) pg/mg], possibly because acute exposures during an aflatoxicosis outbreak in 2004 may have masked any potential underlying relationship.

CONCLUSIONS

Exposure to aflatoxin was associated with childhood chronic hepatomegaly in 2002. These preliminary data suggest an additional health risk that may be related to aflatoxin exposure in children, a hypothesis that merits further testing.

Ibuprofen hepatic encephalopathy, hepatomegaly, gastric lesion and gastric pentadecapeptide BPC 157 in rats

Chronic ibuprofen (0.4 g/kg intraperitoneally, once daily for 4 weeks) evidenced a series of pathologies, not previously reported in ibuprofen-dosed rats, namely hepatic encephalopathy, gastric lesions, hepatomegaly, increased AST and ALT serum values with prolonged sedation/unconsciousness, and weight loss. In particular, ibuprofen toxicity was brain edema, particularly in the cerebellum, with the white matter being more affected than in gray matter. In addition, damaged and red neurons, in the absence of anti-inflammatory reaction was observed, particularly in the cerebral cortex and cerebellar nuclei, but was also present although to a lesser extent in the hippocampus, dentate nucleus and Purkinje cells. An anti-ulcer peptide shown to have no toxicity, the stable gastric pentadecapeptide BPC 157 (GEPPPGKPADDAGLV, MW 1419, 10 μg, 10 ng/kg) inhibited the pathology seen with ibuprofen (i) when given intraperitoneally, immediately after ibuprofen daily or (ii) when given in drinking water (0.16 μg, 0.16 ng/ml). Counteracted were all adverse effects, such as hepatic encephalopathy, the gastric lesions, hepatomegaly, increased liver serum values. In addition, BPC 157 treated rats showed no behavioral disturbances and maintained normal weight gain. Thus, apart from efficacy in inflammatory bowel disease and various wound treatments, BPC 157 was also effective when given after ibuprofen.

Over-dose insulin and stable gastric pentadecapeptide BPC 157. Attenuated gastric ulcers, seizures, brain lesions, hepatomegaly, fatty liver, breakdown of liver glycogen, profound hypoglycemia and calcification in rats

We focused on over-dose insulin (250 IU/kg i.p.) induced gastric ulcers and then on other disturbances that were concomitantly induced in rats, seizures (eventually fatal), severely damaged neurons in cerebral cortex and hippocampus, hepatomegaly, fatty liver, increased AST, ALT and amylase serum values, breakdown of liver glycogen with profound hypoglycemia and calcification development. Calcium deposits were present in the blood vessel walls, hepatocytes surrounding blood vessels and sometimes even in parenchyma of the liver mainly as linear and only occasionally as granular accumulation. As an antidote after insulin, we applied the stable gastric pentadecapeptide BPC 157 (10 microg/kg) given (i) intraperitoneally or (ii) intragastrically immediately after insulin. Controls received simultaneously an equivolume of saline (5 ml/kg). Those rats that survived till the 180 minutes after over-dose application were further assessed. Interestingly, pentadecapeptide BPC 157, as an antiulcer peptide, may besides stomach ulcer consistently counteract all insulin disturbances and fatal outcome. BPC 157 rats showed no fatal outcome, they were mostly without hypoglycemic seizures with apparently higher blood glucose levels (glycogen was still present in hepatocytes), less liver pathology (i.e., normal liver weight, less fatty liver), decreased ALT, AST and amylase serum values, markedly less damaged neurons in brain and they only occasionally had small gastric lesions. BPC 157 rats exhibited mostly only dot-like calcium presentation. In conclusion, the success of BPC 157 therapy may indicate a likely role of BPC 157 in insulin controlling and BPC 157 may influence one or more causative process(es) after excessive insulin application.

Overweight and structural alterations of the liver in female rats fed a high-fat diet: a stereological and histological study

BACKGROUND/AIMS

The aim of the present study was to investigate the effects of a fatty diet on body weight and liver morphometry in rats via modern stereological methods accompanied by a histological evaluation.

METHODS

Eight female "Sprague Dawley" rats were fed a diet constituted highly of fat (30%) for 3 months (the HFD group). Eight control rats were maintained with a standard rat chow. The naso-anal length and body weight of the animals were measured periodically to calculate body mass index. After 3 months, whole livers from the rats were removed, and the volume of each fresh liver was estimated using the water immersion method. After the histological procedure, the volume of paraffin-embedded livers was also estimated using the "Cavalieri" method. Additionally, volumes of the sinusoids and parenchyma were separately estimated with "Cavalieri" method. The mean numerical density, mean nuclear height, and total number of hepatocytes were calculated using the physical disector method. Liver sections were also examined at light and electron microscopic levels.

RESULTS

The body mass indexs of the animals in the control and HFD groups were 4.536+/-0.221 kg/m2 and 5.581+/-0.42 kg/m2, respectively (p<0.01, Mann-Whitney U test). The mean liver volumes (LVs) measured with water immersion method in the control and HFD groups were 10.51 ml and 11.8 ml, respectively. LVs estimated with "Cavalieri" method were 9.98 ml in the control group and 11.095 ml in the HFD group. The differences in LVs between groups were statistically significant when estimated with both methods, indicating that the LV of the HFD group is higher than that of the control group (p<0.05, Mann-Whitney U test). There was no significant difference between LVs estimated via the two different methods in each group (p>0.05, Wilcoxon test). The volume of sinusoids was increased in the HFD group, but the volume of parenchyma was decreased (p<0.05, Mann-Whitney U test). The mean numerical density, mean nuclear height, and total number of hepatocytes were significantly decreased in the HFD group (p<0.05, Mann-Whitney U test). However, the numerical density and total number of binucleated hepatocytes were significantly higher in the HFD group compared with the control group (p<0.05, Mann-Whitney U test). Light and electron microscopic investigations of the HFD group showed a prominent sinusoidal dilatation, microvesicular steatosis, and an increase in connective tissue in the livers and highly dilated smooth endoplasmic reticulum, irregular mitochondria and microvilli and necrosis in the hepatocytes.

CONCLUSIONS

We have shown that a fatty diet in rats causes obesity and may lead to morphological alterations in the liver such as hepatomegaly accompanied by histopathological changes.

Anabolic-androgenic steroids and liver injury

Athletes and nonathletes have been using anabolic-androgenic steroids (AAS) for a long time, in an inadequate and unsurveilled manner, with the aim of improving sports performance or for cosmetic purposes. AAS consumption is becoming more widespread and involving younger people, and there is a trend for self-administration of higher doses and for combining AAS with other potentially harmful drugs. Almost any subject abusing AAS will experience adverse effects. Therefore, adverse effects from these exposures, including liver toxicity, are expected to increase in the years to come. The present manuscript describes a representative case of intrahepatic cholestasis with the intention to discuss AAS-related liver toxicity (including the potential therapeutic role of ursodeoxycholic acid) and to comment on several aspects of the clinical scenario the gastroenterologist should be aware of.

Impact of nutrition on phenotype in CFTR-deficient mice

To elucidate the impact of nutrition in cystic fibrosis (CF), we compared the phenotypic traits of Cftr -/- mice fed either a lipid-enriched liquid diet (Peptamen) or a standard chow combined with polyethylenglycol osmotic laxative (PEG), two strategies commonly used to prevent intestinal obstruction in CF mice. Survival, growth, liver, and ventilatory status were determined in Cftr -/- and Cftr +/+ mice, followed-up until 120 d. Ventilation was recorded in conscious animals using whole-body plethysmography. We found that the survival rate was similar in Peptamen and PEG Cftr -/- mice. Cftr -/- mice had lower minute ventilation than Cftr +/+ mice, whatever the diet. Both Cftr -/- and Cftr +/+ mice fed Peptamen displayed preadult growth delay compared with PEG-treated animals. Despite subsequent growth catch-up, Cftr -/- mice remained smaller than Cftr +/+ mice, whatever the diet. All Peptamen fed Cftr -/- mice showed hepatomegaly and liver steatosis, which also occurred but to a lesser extent in Peptamen fed Cftr +/+ animals. Therefore, while both treatment strategies are similarly efficient to avoid high mortality at weaning, Peptamen induces preadult growth delay and liver steatosis. These effects of diet are important to consider in future animal studies and also prompt to evaluate high-energy diets in CF patients.

Severe hepatitis with prolonged cholestasis and bile duct injury due the long-term use of ornidazole

Nitroimidazole derivatives are commonly used in the treatment of protozoal and anaerobic infections, and reports of their hepatotoxicity are rare. We report a case of severe hepatitis due to the long-term (8 weeks) use of ornidazole. A 27-year-old woman presented for evaluation of elevated serum transaminase and total bilirubin levels. Liver biopsy revealed portal inflammation, hepatocellular and canalicular cholestasis, porto-portal and portocentral bridging fibrosis, and a tendency to form nodules. No aetiological factors associated with chronic liver disease were identified. The abdominal ultrasonographic findings were compatible with chronic liver disease. We therefore made the diagnosis of severe hepatitis resulting from the long-term use of ornidazole. We conclude that nitroimidazole derivatives may lead to serious liver damage, especially in female patients.

Morphological and functional changes in p-glycoprotein during dexamethasone-induced hepatomegaly

1. The effect of dexamethasone on hepatic and renal P-glycoprotein (P-gp) expression, localization and activity was investigated in rats after 4 days oral administration of two dose regimens (1 or 25 mg/kg per day). Simultaneous increases in liver weight were evaluated by quantitative histological examination. 2. In the liver, dexamethasone pretreatment produced hepatomegaly as a consequence of extensive periportal fat accumulation, which was quantified by densitometry of oil red O-stained liver sections. Quantitative immunohistochemical analysis revealed preferential periportal zonation of P-gp in control animals. Dexamethasone pretreatment resulted in spatially disproportional induction of P-gp protein expression within the liver acinus characterized by preferential increase in pericentral areas, with consequent uniform panlobular distribution. Western blot analysis confirmed these results, showing increases in P-gp protein. Quantitative reverse transcription-polymerase chain reaction analysis revealed no statistically significant change in liver mdr1b mRNA expression after either dexamethasone treatment regimen. The expression of mdr1a mRNA was significantly decreased by 85-87%. 3. In the kidney, dexamethasone reduced mdr1a mRNA expression by 69-89%, whereas mdr1b mRNA expression was increased in a dose-dependent manner. However, despite tendencies, no significant increases in P-gp expression were observed at the protein level. 4. The in vivo function of P-gp was evaluated by measuring renal and biliary secretion of rhodamine-123 (Rho123) under a steady state plasma concentration. The biliary, renal and tubular secretory clearance of Rho123 was significantly increased only after high-dose dexamethasone. 5. In conclusion, the present study suggests that drug interactions observed during corticosteroid therapy may be mediated, at least in part, through increased biliary, and also renal, excretion of P-gp substrates. Expression of P-gp in the liver showed primary periportal zonation with differential changes during induction. Accompanying hepatomegaly may be explained by severe microvesicular steatosis selectively localized to the periportal areas.

Effects of fenofibrate and xuezhikang on high-fat diet-induced non-alcoholic fatty liver disease

1. Fenofibrate and xuezhikang are two types of drugs widely used in the treatment of dyslipidaemia in China. The main purpose of present study was to test the efficacies and explore the potential mechanisms of action of the two lipid-lowering agents on high-fat diet-induced non-alcoholic fatty liver disease (NAFLD). 2. Rats were randomly divided into four groups, with eight rats per group. One group was given normal diet, whereas the other three groups were fed a high-fat diet. Forty-two days later, two of the high-fat diet-fed groups were administered fenofibrate (100 mg/kg, p.o.) and xuezhikang (300 mg/kg, p.o.) for another 42 consecutive days. The other two groups were administered placebo (saline) by gavage. 3. Typical pathological symptoms of NAFLD occurred in the high-fat diet groups. Fenofibrate and xuezhikang treatment markedly improved NAFLD, ameliorating dyslipidaemia and fat accumulation in the liver, improving insulin resistance and ameliorating oxidative stress. Hepatic steatosis, necro-inflammation and collagen deposition were lessened in the drug-treated groups. However, both xuezhikang and fenofibrate failed to reverse hepatomegaly and fenofibrate even aggravated it. Xuezhikang reversed aminotransferase abnormalities, but fenofibrate had less of an effect. 4. The common therapeutic mechanism of action of fenofibate and xuezhikang likely involves inhibition of the hepatic expression of tumour necrosis factor-alpha. Fenofibrate upregulated mRNA levels of peroxisome proliferator-activated receptor (PPAR) alpha in the liver, whereas xuezhikang had no effect on the hepatic expression of PPARalpha and this may explain, in part, their different effects on the NAFLD rats. 5. The results suggest that fenofibrate and xuezhikang may have potential clinical application in the treatment of NAFLD. However, the side-effects of fenofibrate and the underlying constituents of xuezhikang need to be determined and investigated further.

A host lipase detoxifies bacterial lipopolysaccharides in the liver and spleen

Much of the inflammatory response of the body to bloodborne Gram-negative bacteria occurs in the liver and spleen, the major organs that remove these bacteria and their lipopolysaccharide (LPS, endotoxin) from the bloodstream. We show here that LPS undergoes deacylation in the liver and spleen by acyloxyacyl hydrolase (AOAH), an endogenous lipase that selectively removes the secondary fatty acyl chains that are required for LPS recognition by its mammalian signaling receptor, MD-2-TLR4. We further show that Kupffer cells produce AOAH and are required for hepatic LPS deacylation in vivo. AOAH-deficient mice did not deacylate LPS and, whereas their inflammatory responses to low doses of LPS were similar to those of wild type mice for approximately 3 days after LPS challenge, they subsequently developed pronounced hepatosplenomegaly. Providing recombinant AOAH restored LPS deacylating ability to Aoah(-/-) mice and prevented LPS-induced hepatomegaly. AOAH-mediated deacylation is a previously unappreciated mechanism that prevents prolonged inflammatory reactions to Gram-negative bacteria and LPS in the liver and spleen.

Transarterial versus Transhepatic Portal Vein Embolization to Induce Selective Hepatic Hypertrophy: A Comparative Study in Swine

PURPOSE

Portal vein embolization (PVE) is used to induce liver hypertrophy for surgical candidates with marginal future liver remnant (FLR) volumes. We compared the feasibility, safety, and effectiveness of a transarterial approach for PVE (TA-PVE) with those of a transhepatic approach for PVE (TH-PVE) in a swine model.

MATERIALS AND METHODS

Ten experimental pigs (TA-PVE, n = 5; TH-PVE, n = 5) and six controls (TA, n = 3; TH, n = 3) were studied. For TA-PVE, a microcatheter was advanced into arteries supplying the left and left middle hepatic lobes. A 3 to 1 Ethiodol-ethanol mixture was infused into selected arteries to cross the arterioportal peribiliary plexus and remain within the portal veins (PVs). For TH-PVE, PVs in the same lobar distribution were embolized with 355- to 500-micro m polyvinyl alcohol particles and coils. Controls were similarly catheterized for saline infusion. Computed tomography with volumetry was performed before and 7, 14, 21, and 28 days after PVE to assess FLR hypertrophy (absolute FLR volume change and FLR/total liver volume [TLV]). Computed tomographic volumetry, laboratory data, and histopathology were compared between groups.

RESULTS

All procedures were technically successful. The increases in mean absolute FLR volume (TA-PVE, 148 +/- 84 cm(3); TH-PVE, 62 +/- 19 cm(3); P = .082), mean FLR hypertrophy (TA-PVE, 93.2%; TH-PVE, 48.4%; P = .178), and mean FLR/TLV (TA-PVE, 31.0%; TH-PVE, 16.2%; P = .130) from day 0 to day 28 between experimental groups were better for TA-PVE. Changes in laboratory data among all groups were minimal. Two complications occurred from TA-PVE (right gastric artery embolization [n = 2] without sequela) and two from TH-PVE (acute segmental right PV thrombosis [n = 1]; death 3 weeks after PVE of unknown cause [n = 1]).

CONCLUSIONS

Transarterial portal vein embolization is feasible, safe, and effective for inducing future liver remnant hypertrophy in swine and may represent an improvement over previously reported transhepatic portal vein embolization methods.

Transcriptomic and phylogenetic analysis of Kpna genes: a family of nuclear import factors modulated in xenobiotic-mediated liver growth

OBJECTIVES

We have identified a member of the karyopherin (importin) alpha family of nuclear import factors as being modulated in rat liver following exposure to the hypolipidaemic and liver growth agent Wy-14,643. To examine the hypothetical role of this protein family as a checkpoint in receptor-mediated signalling, we characterized the rat karyopherin alpha (Kpna) gene family and present cDNA sequences and gene structures for all six rat Kpna genes. Further, we have assembled a comprehensive panel of Kpna coding regions from a range of metazoa, which we have subjected to phylogenetic analysis: This represents by far the most complete phylogenetic study of metazoan karyopherins, including several evolutionary intermediates not previously examined. The phylogeny reveals three Kpna subfamilies with distinct, conserved gene structures, shedding light on the evolutionary origins of this multigene family in metazoa.

METHODS AND RESULTS

Using quantitative PCR, we have analysed Kpna transcript levels in 44 rat tissues; Kpna transcripts show a wide variation in their distribution both in absolute and relative terms, suggestive of specialized roles for each member. We also demonstrate that Kpna genes are regulated in rat liver and isolated hepatocytes in a xenobiotic-specific manner for a number of chemically distinct liver growth agents.

CONCLUSIONS

In light of the crucial role of nuclear import in mediating the genomic changes elicited through nuclear receptor activation, we postulate that changes in the levels of specific karyopherins alpha during xenobiotic-mediated liver growth represent an important component of the cellular response to the external stimuli that trigger these events.

Activation of Wnt/beta-catenin pathway during hepatocyte growth factor-induced hepatomegaly in mice

Hepatocyte growth factor (HGF) and beta-catenin both play a crucial role in stimulating hepatocyte proliferation, but whether these 2 pathways cooperate in inducing hepatocyte proliferation is unclear. We have previously reported that beta-catenin forms a complex with c-Met (HGF receptor) that undergoes dissociation because of beta-catenin tyrosine phosphorylation on stimulation by HGF. It is also known that delivery of the human HGF gene cloned in a plasmid under a CMV promoter results in hepatomegaly in mice. In addition, recently characterized beta-catenin transgenic mice also showed hepatomegaly. The present study was based on the hypothesis that HGF-induced hepatomegaly is mediated, at least in part, by activation of the Wnt/beta-catenin pathway. Here we report that delivery of the human HGF gene delivery in mice led to hepatomegaly via beta-catenin activation in the liver in 1- and 4-week studies. The mechanisms of beta-catenin activation in the 1-week study included loss of c-Met-beta-catenin association as well as canonical beta-catenin activation, leading to its nuclear translocation. In the 4-week study, beta-catenin activation was observed via canonical mechanisms, whereas the c-Met-beta-catenin complex remained unchanged. In both studies there was an associated increase in the E-cadherin-beta-catenin association at the membrane. In addition, we generated liver-specific beta-catenin knockout mice, which demonstrated significantly smaller livers. HGF gene delivery failed to induce hepatomegaly in these beta-catenin conditionally null mice. In conclusion, beta-catenin- and HGF-mediated signaling pathways cooperate in hepatocyte proliferation, which may be crucial in liver development, regeneration following partial hepatectomy, and pathogenesis of hepatocellular carcinoma.

Pharmacologic transglutaminase inhibition attenuates drug-primed liver hypertrophy but not Mallory body formation

Mallory bodies (MBs) are characteristic of several liver disorders, and consist primarily of keratins with transglutaminase-generated keratin crosslinks. We tested the effect of the transglutaminase-2 (TG2) inhibitor KCC009 on MB formation in a mouse model fed 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). KCC009 decreased DDC-induced liver enlargement without affecting MB formation or extent of liver injury. TG2 protein and activity increased after DDC feeding and localized within and outside hepatocytes. KCC009 inhibited DDC-induced hepatomegaly by affecting hepatocyte cell size rather than proliferation. Hence, TG2 is a potential mediator of injury-induced hepatomegaly via modulation of hepatocyte hypertrophy, and KCC009-mediated TG2 inhibition does not affect mouse MB formation.

Rapid onset of glycogen storage hepatomegaly in a type-2 diabetic patient after a massive dose of long-acting insulin and large doses of glucose

We present a case of rapid onset of glycogen storage hepatomegaly, caused by a massive dose of long-acting insulin and large doses of glucose, in a type-2 diabetic patient. A 41-year-old man was admitted to our hospital because of hypoglycemia and unconsciousness following subcutaneous administration of 180 units of insulin glargine in a suicide attempt. Despite continuous hypercaloric infusion with additional intravenous glucose injections, hypoglycemia persisted for 36 hours. Although the hepatic function was normal and no hepatomegaly was detected on admission, the liver function tests became abnormal and hepatomegaly was detected on hospitalization day 3. Plain abdominal computed tomography (CT) scanning confirmed liver enlargement, with hepatic CT attenuation markedly elevated at 83.7 HU. Liver biopsy revealed hepatocytic glycogen deposition with edematous degeneration. Based on these findings, the diagnosis was made as rapid onset glycogen storage hepatomegaly caused by administration of a massive dose of long-acting insulin and supplementation with large doses of glucose. With improved glycemic control, the liver function improved, the CT findings of hepatomegaly improved, and the hepatic CT attenuation decreased. Repeat liver biopsy also confirmed almost complete disappearance of glycogen deposits. When hepatic dysfunction or hepatomegaly is detected during treatment with insulin, the possibility of hepatic glycogen deposition should be considered. CT scanning and liver biopsy were useful in diagnosing this case.

Responses of the Liver to Perfluorinated Fatty Acids with Different Carbon Chain Length in Male and Female Mice:In Relation to Induction of Hepatomegaly, Peroxisomal .BETA.-Oxidation and Microsomal 1-Acylglycerophosphocholine Acyltransferase

The potency of the induction of hepatomegaly, peroxisomal beta-oxidation and microsomal 1-acylglycerophoshocholine (1-acyl-GPC) acyltransferase was compared among perfluorinated fatty acids (PFCAs) with 6-9 carbon chain length in the liver of male and female mice. All PFCAs examined induced hepatomegaly and peroxisomal beta-oxidation and the potency was in the order of perfluorononanonic acid (PFNA), perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHA) and perfluorohexanoic acid (PFHeA) when compared with the relative doses to induce the two parameters. Microsomal 1-acyl-GPC acyltransferase was induced by PFHA, PFOA and PFNA, as was peroxisomal beta-oxidation. No significant sex-related difference was observed in the induction of peroxisomal beta-oxidation by any PFCAs examined. PFNA and PFOA accumulated in the liver of both male and female mice in a dose-dependent manner. PFHA accumulated in the liver to a lesser extent; little PFHeA accumulated in the liver. Hepatic concentrations of PFNA, PFOA and PFHA were higher in male mice than those in female mice. One linear regression line was confirmed between the activities of peroxisomal beta-oxidation and hepatic concentrations of PFHeA, PFHA, PFOA and PFNA in male mice regardless of their carbon chain lengths, and the activities were saturable at the concentrations over approximately 500 nmol/g liver. Similar linear regression line was obtained between the two parameters in female mice. These results suggest (i) that the longer the perfluoroalkyl chain becomes, the more PFCA accumulates in the liver of both male and female mice, (ii) that the accumulated PFCAs induce hepatomegaly, peroxisomal beta-oxidation and microsomal 1-acyl-GPC acyltransferase, and (iii) that the difference observed in the accumulation of PFHA, PFOA and PFNA in the liver between male and female mice is not enough to produce obvious sex-related difference in the induction of peroxisomal beta-oxidation.

Toxic Effects of Fumonisin in Mouse Liver Are Independent of the Peroxisome Proliferator-Activated Receptor α

Fumonisin mycotoxins occur worldwide in corn and corn-based foods. Fumonisin B1 (FB1) is a rodent liver carcinogen and suspected human carcinogen. It inhibits ceramide synthase and increases tissue sphinganine (Sa) and sphingosine (So) concentrations. Events linking disruption of sphingolipid metabolism and fumonisin toxicity are not fully understood; however, Sa and So were shown to bind mouse recombinant peroxisome proliferator-activated receptor alpha (PPARalpha) in vitro. To investigate the role of PPARalpha in fumonisin hepatotoxicity in vivo, wild-type (WT) and PPARalpha-null mice were fed control diets or diets containing 300 ppm FB1, Fusarium verticillioides culture material (CM) providing 300 ppm FB1, or 500 ppm of the peroxisome proliferator WY-14,643 (WY) for 1 week. WY-fed WT mice exhibited hepatomegaly, an effect not found in WY-fed PPARalpha-null mice, and WY did not change liver sphingoid base concentrations in either strain. Hepatotoxicity found in FB1- and CM-fed WT and PPARalpha-null mice was similar, qualitatively different from that found in WY-treated animals, and characterized by increased Sa concentration, apoptosis, and cell proliferation. Transcript profiling using oligonucleotide arrays showed that CM and FB1 elicited similar expression patterns of genes involved in cell proliferation, signal transduction, and glutathione metabolism that were different from that altered by WY. Real-time RT-PCR analysis of gene expression demonstrated PPARalpha-dependence of lipid metabolism gene expression in WY-treated mice, whereas PPARalpha-independent alterations of genes in lipid metabolism, and other categories, were found in CM- and FB1-fed mice. Together, these findings demonstrate that FB1- and CM-induced hepatotoxicity in mice does not require PPARalpha.

[Propofol infusion syndrome in children]

Propofol infusion syndrome, characterised by cardiovascular collapse, metabolic acidosis, hepatomegaly, renal failure and rhabdomyolysis, is a rare and often fatal syndrome seen in critically ill children undergoing long-term propofol sedation. Propofol may impair mitochondrial free fatty acid metabolism, resulting in an imbalance between energy demand and utilisation and thus compromising cardiac and peripheral muscle cell function. Propofol should be used with caution for sedation in critically ill children, as well as for long-term anaesthesia in otherwise healthy children, and doses exceeding 4 mg/kg/h should be avoided.

Toxicological Effects of Gestational and Lactational Exposure to a Mixture of Persistent Organochlorines in Rats: Systemic Effects

A large multi-disciplinary study was conducted to investigate the systemic, neurodevelopmental, neurochemical, endocrine, and molecular pathological effects of a mixture of reconstituted persistent organochlorine pollutants (POP) based on the blood profiles of Canadians residing in the Great Lakes/St. Lawrence region. This report outlines the overall study design and describes the systemic effects in rat offspring perinatally exposed to the POP mixture. Maternal rats were administered orally 0, 0.013, 0.13, 1.3, or 13 mg/kg bw/day of the mixture from gestational day (GD) 1 to postnatal day (PND) 23. Positive and negative controls were given Aroclor 1254 (15 mg/kg bw/day) and corn oil (vehicle), respectively. The rat pups were reared, culled to 8 per litter, and killed on postnatal days 35, 70, and 350, at which time tissues were collected for analysis. Exposure to high doses of the mixture elicited clinical, biochemical, and pathological changes and high mortality rates in rat offspring. Aroclor 1254 produced similar effects but a lower mortality than was seen in POP mixture groups. Biochemical changes consisted of increased liver microsomal activities and elevated serum cholesterol. Hepatomegaly was observed in the highest dose group of the mixture and in the positive control. Liver, thymus, and spleen were the target organs of action. Microscopic changes in the liver consisted of vacuolation and hypertrophy, and those in the thymus were characterized by reduced cortical and medullary volume. The spleen showed a treatment-related reduction in lymphocyte density and lymphoid areas. This study demonstrates that exposure to the POP mixture up to 13 mg/kg/day perinatally produced growth suppression, elevated serum cholesterol, increased liver microsomal enzyme activities, and immunopathological changes in the thymus and spleen, and lethality. Most of the effects were seen at dose levels much higher than expected human exposure.

Effect of chronic intake of arsenic-contaminated water on liver

The hepatotoxic effect of arsenic when used in therapeutic dose has long been recognized. We described the nature and degree of liver involvement and its pathogenesis due to prolonged drinking of arsenic-contaminated water in West Bengal, India. From hospital-based studies on 248 cases of arsenicosis, hepatomegaly was found in 190 patients (76.6%). Non cirrhotic portal fibrosis was the predominant lesions in 63 out of 69 cases who underwent liver biopsy. The portal fibrosis was characterized by expansion of portal zones with streaky fibrosis, a few of which contained leash of vessels. However, portal hypertension was found in smaller number of cases. A cross-sectional epidemiological study was carried out on 7683 people residing in arsenic-affected districts of West Bengal. Out of these, 3467 and 4216 people consumed water-containing arsenic below and above 0.05 mg/l, respectively. Prevalence of hepatomegaly was significantly higher in arsenic-exposed people (10.2%) compared to controls (2.99%, P < 0.001). The incidence of hepatomegaly was found to have a linear relationship proportionate to increasing exposure of arsenic in drinking water in both sexes (P < 0.001). In an experimental study, BALB/C mice were given water contaminated with arsenic (3.2 mg/l) ad libitum for 15 months, the animals being sacrificed at 3-month intervals. We observed progressive reduction of hepatic glutathione and enzymes of anti-oxidative defense system associated with lipid peroxidation. Liver histology showed fatty infiltration at 12 months and hepatic fibrosis at 15 months. Our studies show that prolong drinking of arsenic-contaminated water is associated with hepatomegaly. Predominant lesion of hepatic fibrosis appears to be caused by arsenic induced oxystress.

Exogenous thyroid hormone induces liver enlargement, whilst maintaining regenerative potential--a study relevant to donor preconditioning

We have investigated thyroid hormone- (T3) induced liver cell hyperplasia in rats to explore the potential utility of primary mitogens within the clinical context of donor conditioning prior to living-related transplantation. A single injection of T3 induced a semi-synchronized proliferative response in hepatocytes, resulting at 10 days in a peak increase in liver mass, liver/body mass ratio, total DNA and total protein. Importantly, the hyperplastic liver induced by T3 exhibits a commensurate increase in metabolic capacity, as assessed by enhanced galactose elimination capacity. Furthermore, when the liver mass had been increased by an injection of T3 given 10 days previously and 70% partial hepatectomy performed, there was a larger remnant liver mass, liver/body mass ratio, total DNA and total protein content 24 h after surgery, compared with animals given a control injection. Interestingly, the regenerative response to surgery was the same in both groups, indicating that prior T3 conditioning did not impair the regenerative response of the liver. Using more stringent conditions to test hepatic functional reserve, following 90% hepatectomy, there was a greater (57%) survival in animals pre-treated with T3 compared to 14% in controls.

Long-term analysis of the palliative benefit of 2-chlorodeoxyadenosine for myelofibrosis with myeloid metaplasia

OBJECTIVE

Therapeutic splenectomy in myelofibrosis with myeloid metaplasia (MMM) may result in extreme thrombocytosis and leukocytosis and accelerated hepatomegaly. We previously described initial palliative benefit from 2-chlorodeoxyadenosine (2-CdA) in such instances. The purpose of this study is to provide long-term follow-up on the durability of response in the initial cohort and in additional subsequent cases.

METHODS

We retrospectively identified patients with histologically confirmed MMM who had palliative therapy with 2-CdA. Clinical characteristics and information on subsequent clinical course were abstracted at the time of diagnosis of MMM and at initiation of 2-CdA therapy until death.

RESULTS

To date, we have used 2-CdA as palliative therapy in 14 patients with MMM. After a median of four cycles of therapy, responses for hepatomegaly occurred in 56% of patients, thrombocytosis 50%, leukocytosis 55%, and anemia 40%. Cytopenias were frequent but usually transient and without clinical consequence. Responses occurred usually by the second cycle; median duration of response was 6 months (range, 2-19) after completion of 2-CdA therapy.

CONCLUSION

This study confirmed relevant and frequently durable palliation of symptoms in about half the patients. 2-CdA is a reasonable palliative option in postsplenectomy patients with MMM who have problematic myeloproliferation.

Prolonged feeding of mice with conjugated linoleic acid increases hepatic fatty acid synthesis relative to oxidation

Feeding mice conjugated linoleic acid (9 cis,11 trans/9 trans,11 cis-and 10 trans,12 cis-CLA in equal amounts) resulted in triacylglycerol accumulation in the liver. The objective of this study was to examine whether this steatosis is associated with changes in hepatic fatty acid synthesis and oxidation. Therefore, we measured the activities of key enzymes of fatty acid synthesis, i.e., acetyl-CoA carboxylase and fatty acid synthase and of fatty acid oxidation, i.e., 3-hydroxy-acyl-CoA dehydrogenase and citrate synthase in livers of mice fed a diet with 0.5% (w/w) CLA. CLA (a 1:1 mixture of the 10 trans, 12 cis and 9 cis, 11 trans isomers of octadecadenoic acid) was administered for 3 and 12 weeks with high-oleic sunflower oil fed as control. The proportion of body fat was significantly lower on the CLA than on the control diet and this effect was already significant after 3 weeks. The specific activites of 3-hydroxy-acyl-CoA dehydrogenase and citrate synthase were unaffected by CLA both after 3 and 12 weeks. The specific activity of fatty acid synthase was nonsignificantly raised (by 12%) after 3 weeks on the CLA diet but had increased significantly (by 34%) after 12 weeks of feeding. The specific activity of acetyl-CoA carboxylase had also increased both after 3 weeks (by 53%) and 12 weeks (by 23%) on the CLA diet, but this effect did not reach statistical significance. Due to CLA-induced hepatomegaly, the overall capacity for both fatty acid oxidation and synthesis-as evidenced by the total hepatic activities of 3-hydroxy-acyl-CoA dehydrogenase, citrate synthase, acetyl-CoA carboxylase, and fatty acid synthase-was significantly greater in the CLA-fed group after 12 weeks, although the overall capacity for fatty acid synthesis had increased more than that for fatty acid oxidation. Thus, this study indicates that prolonged, but not short-term, feeding mice with CLA increased hepatic fatty acid synthesis relative to oxidation, despite the decrease in body fat and the increase in liver weight seen earlier. It is concluded that the observed CLA-induced changes in hepatic fatty acid synthesis and oxidation are the result, rather than the cause, of the lowering of body fat.

Enhanced potential for oxidative stress in livers of senescent rats by the peroxisome proliferator-activated receptor alpha agonist perfluorooctanoic acid

Aging sensitizes the liver to the hepatocarcinogenic effect of PPARalpha agonists via unknown mechanisms. This study was designed to investigate age-dependent, hepatic effects of the non-metabolizable PPARalpha agonist perfluorooctanoic acid (PFOA) on the delicate balance between activities of pathways involved in H(2)O(2) production and elimination. Male Fischer-344 rats, ranging in age from juvenile (4 weeks old), post puberty (10 weeks old), mature adulthood (20 weeks old), middle age (50 weeks old), to senescence (100 weeks old), were treated intragastrically with either 150mg PFOA/kg in 0.5ml corn oil, or with corn oil alone. Animals were sacrificed at predetermined time-points ranging from 0-28 days post PFOA or oil administration. Hepatic peroxisomal beta-oxidizing activities were significantly elevated (four- to six-fold) in all age groups by PFOA. While levels declined to near basal values within 3-7 days in 4 and 10, they remained elevated for an additional week in 20-, 50- and 100-week-old rats. However, catalase activity was significantly lower in senescent livers compared with all other groups. In conclusion, aging does not appear to hinder the capacity of the liver to produce excess H(2)O(2) through peroxisomal beta-oxidation upon exposure to PPAR agonists. However, the reduced ability of the senescent liver to recover from PFOA-induced potential increase in H(2)O(2) production, coupled with the apparent diminished capacity of this liver to decompose H(2)O(2), enhances the potential for hepatic oxidative damage in aged animals. This may explain the enhanced susceptibility of the senescent liver to the hepatocarcinogenic effect of PPAR agonists.

Protective Effects of Vitamin A and Vitamin E Succinate against 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-Induced Body Wasting, Hepatomegaly, Thymic Atrophy, Production of Reactive Oxygen Species and DNA Damage in C57BL/6J Mice

The protective effect of vitamin A and vitamin E succinate against 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced acute toxicity and measures of oxidative stress was studied. Ten mice were treated with either vitamin A (50 mg/kg every other day for eight days) or vitamin E succiante (150 mg/kg/day followed by a dose of 40 mg/kg/day for five additional days). Half of each of the above groups of animals received TCDD on day 4. Five mice received corn oil or TCDD alone. After five days of TCDD treatment, antioxidant combination treatment with vitamin A and TCDD or vitamin E succinate and TCDD resulted in a significant reduction in indicators of acute toxicity including the decrease in total body and thymus weight as compared to TCDD alone (P<0.05). The combination treatment produced also a significant reduction in the increase in liver weight as compared to TCDD only (P<0.05). Following one day of treatment with 50 microg TCDD/kg, vitamin A and vitamin E succinate produced a significant decrease in the production of superoxide anion by peritoneal lavage cells (P<0.05) and in DNA-single strand breaks in the same cells (P<0.05) as assessed by the reduction of cytochrome c and the alkaline elution technique, respectively. A significant decrease in DNA-single strand breaks in peritoneal lavage cells was observed following 5 days treatment with 50 microg TCDD/kg (P<0.05). The results indicate a potential role for oxidative stress in the acute toxicity of TCDD and a protective effect for vitamin A and vitamin E succinate in the overall toxicity of TCDD including measures of oxidative stress.

Hepatitis After Sevoflurane Exposure in an Infant Suffering from Primary Hyperoxaluria Type 1

An 11-mo-old child with primary hyperoxaluria was scheduled for a nephroureteromia procedure. Anesthesia was induced and maintained with sevoflurane. Two days after the operation, a hepatomegaly was diagnosed, and a considerable increase in liver enzymes was observed. These pathologic findings disappeared without treatment within 7 days. In a subsequent operation 2 wk later, general anesthesia was performed (sevoflurane was avoided). After the second operation, no pathologic findings could be detected. Nothing in this patient's disease or the conduct of the anesthesia suggested a cause for the injury other than an idiosyncratic response to sevoflurane.

Disruption of hepatic lipid homeostasis in mice after amiodarone treatment is associated with peroxisome proliferator-activated receptor-alpha target gene activation

Amiodarone, an efficacious and widely used antiarrhythmic agent, has been reported to cause hepatotoxicity in some patients. To gain insight into the mechanism of this unwanted effect, mice were administered various doses of amiodarone and examined for changes in hepatic histology and gene regulation. Amiodarone induced hepatomegaly, hepatocyte microvesicular lipid accumulation, and a significant decrease in serum triglycerides and glucose. Northern blot analysis of hepatic RNA revealed a dose-dependent increase in the expression of a number of genes critical for fatty acid oxidation, lipoprotein assembly, and lipid transport. Many of these genes are regulated by the peroxisome proliferator-activated receptor-alpha (PPARalpha), a ligand-activated nuclear hormone receptor transcription factor. The absence of induction of these genes as well as hepatomegaly in PPARalpha knockout [PPARalpha-/-] mice indicated that the effects of amiodarone were dependent upon the presence of a functional PPARalpha gene. Compared to wild-type mice, treatment of PPARalpha-/- mice with amiodarone resulted in an increased rate and extent of total body weight loss. The inability of amiodarone to directly activate either human or mouse PPARalpha transiently expressed in human HepG2 hepatoma cells indicates that the effects of amiodarone on the function of this receptor were indirect. Based upon these results, we conclude that amiodarone disrupts hepatic lipid homeostasis and that the increased expression of PPARalpha target genes is secondary to this toxic effect. These results provide important new mechanistic information regarding the hepatotoxic effects of amiodarone and indicate that PPARalpha protects against amiodarone-induced hepatotoxicity.