Protection against liver damage by cardiotrophin-1: a hepatocyte survival factor up-regulated in the regenerating liver in rats

IP3R1-mediated MAMs formation contributes to mechanical trauma-induced hepatic injury and the protective effect of melatonin

INTRODUCTION

There is a high morbidity and mortality rate in mechanical trauma (MT)-induced hepatic injury. Currently, the molecular mechanisms underlying liver MT are largely unclear. Exploring the underlying mechanisms and developing safe and effective medicines to alleviate MT-induced hepatic injury is an urgent requirement. The aim of this study was to reveal the role of mitochondria-associated ER membranes (MAMs) in post-traumatic liver injury, and ascertain whether melatonin protects against MT-induced hepatic injury by regulating MAMs.

METHODS

Hepatic mechanical injury was established in Sprague-Dawley rats and primary hepatocytes. A variety of experimental methods were employed to assess the effects of melatonin on hepatic injury, apoptosis, MAMs formation, mitochondrial function and signaling pathways.

RESULTS

Significant increase of IP3R1 expression and MAMs formation were observed in MT-induced hepatic injury. Melatonin treatment at the dose of 30 mg/kg inhibited IP3R1-mediated MAMs and attenuated MT-induced liver injury in vivo. In vitro, primary hepatocytes cultured in 20% trauma serum (TS) for 12 h showed upregulated IP3R1 expression, increased MAMs formation and cell injury, which were suppressed by melatonin (100 μmol/L) treatment. Consequently, melatonin suppressed mitochondrial calcium overload, increased mitochondrial membrane potential and improved mitochondrial function under traumatic condition. Melatonin's inhibitory effects on MAMs formation and mitochondrial calcium overload were blunted when IP3R1 was overexpressed. Mechanistically, melatonin bound to its receptor (MR) and increased the expression of phosphorylated ERK1/2, which interacted with FoxO1 and inhibited the activation of FoxO1 that bound to the IP3R1 promoter to inhibit MAMs formation.

CONCLUSION

Melatonin prevents the formation of MAMs via the MR-ERK1/2-FoxO1-IP3R1 pathway, thereby alleviating the development of MT-induced liver injury. Melatonin-modulated MAMs may be a promising therapeutic therapy for traumatic hepatic injury.

CD1d protects against hepatocyte apoptosis in non-alcoholic steatohepatitis

BACKGROUND & AIMS

Hepatocyte apoptosis, a well-defined form of cell death in non-alcoholic steatohepatitis (NASH), is considered the primary cause of liver inflammation and fibrosis. However, the mechanisms underlying the regulation of hepatocyte apoptosis in NASH remain largely unclear. We explored the anti-apoptotic effect of hepatocyte CD1d in NASH.

METHODS

Hepatocyte CD1d expression was analyzed in patients with NASH and mouse models. Hepatocyte-specific gene overexpression or knockdown and anti-CD1d crosslinking were used to investigate the anti-apoptotic effect of hepatocyte CD1d on lipotoxicity-, Fas-, and concanavalin (ConA)-mediated liver injuries. A high-fat diet, a methionine-choline-deficient diet, a Fas agonist, and ConA were used to induce lipotoxic and/or apoptotic liver injuries. Palmitic acid was used to mimic lipotoxicity-induced apoptosis in vitro.

RESULTS

We identified a dramatic decrease in CD1d expression in hepatocytes of patients with NASH and mouse models. Hepatocyte-specific CD1d overexpression and knockdown experiments collectively demonstrated that hepatocyte CD1d protected against hepatocyte apoptosis and alleviated hepatic inflammation and injuries in NASH mice. Furthermore, decreased JAK2-STAT3 signaling was observed in NASH patient livers. Mechanistically, anti-CD1d crosslinking on hepatocytes induced tyrosine phosphorylation of the CD1d cytoplasmic tail, leading to the recruitment and phosphorylation of JAK2. Phosphorylated JAK2 activated STAT3 and subsequently reduced apoptosis in hepatocytes, which was associated with an increase in anti-apoptotic effectors (Bcl-xL and Mcl-1) and a decrease in pro-apoptotic effectors (cleaved-caspase 3/7). Moreover, anti-CD1d crosslinking effectively protected against Fas- or ConA-mediated hepatocyte apoptosis and liver injury in mice.

CONCLUSIONS

Our study uncovered a previously unrecognized anti-apoptotic CD1d-JAK2-STAT3 axis in hepatocytes that conferred hepatoprotection and highlighted the potential of hepatocyte CD1d-directed therapy for liver injury and fibrosis in NASH, as well as in other liver diseases associated with hepatocyte apoptosis.

IMPACT AND IMPLICATIONS

Excessive and/or sustained hepatocyte apoptosis is critical in driving liver inflammation and injury. The mechanisms underlying the regulation of hepatocyte apoptosis in non-alcoholic steatohepatitis (NASH) remain largely unclear. Here, we found that CD1d expression in hepatocytes substantially decreases and negatively correlates with the severity of liver injury in patients with NASH. We further revealed a previously unrecognized anti-apoptotic CD1d-JAK2-STAT3 signaling axis in hepatocytes, which confers significant protection against liver injury in NASH and acute liver diseases. Thus, hepatocyte CD1d-targeted therapy could be a promising strategy to manipulate liver injury in both NASH and other hepatocyte apoptosis-related liver diseases.

HIF inhibitor 32-134D eradicates murine hepatocellular carcinoma in combination with anti-PD1 therapy

Hepatocellular carcinoma (HCC) is a major cause of cancer mortality worldwide and available therapies, including immunotherapies, are ineffective for many patients. HCC is characterized by intratumoral hypoxia, and increased expression of hypoxia-inducible factor 1α (HIF-1α) in diagnostic biopsies is associated with patient mortality. Here we report the development of 32-134D, a low-molecular-weight compound that effectively inhibits gene expression mediated by HIF-1 and HIF-2 in HCC cells, and blocks human and mouse HCC tumor growth. In immunocompetent mice bearing Hepa1-6 HCC tumors, addition of 32-134D to anti-PD1 therapy increased the rate of tumor eradication from 25% to 67%. Treated mice showed no changes in appearance, behavior, body weight, hemoglobin, or hematocrit. Compound 32-134D altered the expression of a large battery of genes encoding proteins that mediate angiogenesis, glycolytic metabolism, and responses to innate and adaptive immunity. This altered gene expression led to significant changes in the tumor immune microenvironment, including a decreased percentage of tumor-associated macrophages and myeloid-derived suppressor cells, which mediate immune evasion, and an increased percentage of CD8⁺ T cells and natural killer cells, which mediate antitumor immunity. Taken together, these preclinical findings suggest that combining 32-134D with immune checkpoint blockade may represent a breakthrough therapy for HCC.

Preclinical models of acute liver failure: a comprehensive review

Acute liver failure is marked by the rapid deterioration of liver function in a previously well patient over period of days to weeks. Though relatively rare, it is associated with high morbidity and mortality. This makes it a challenging disease to study clinically, necessitating reliance on preclinical models as means to explore pathophysiology and novel therapies. Preclinical models of acute liver failure are artificial by nature, and generally fall into one of three categories: surgical, pharmacologic or immunogenic. This article reviews preclinical models of acute liver failure and considers their relevance in modeling clinical disease.

Identification of Methylation-Regulated Differentially Expressed Genes and Related Pathways in Hepatocellular Carcinoma: A Study Based on TCGA Database and Bioinformatics Analysis

Background

In recent years, DNA methylation modification has been shown to be a critical mechanism in the field of epigenetics.

Methods

Hepatocellular carcinoma (HCC) data were obtained from The Cancer Genome Atlas project, including RNA expression profiles, Illumina Human Methylation 450K BeadChip data, clinical information, and pathological features. Then, differentially expressed genes (DEGs) and differentially methylated genes were identified using R software. Methylation-regulated DEGs (MeDEGs) were further analyzed using Spearman’s correlation analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using the DAVID database and ClueGO in Cytoscape software. Kaplan–Meier survival analysis explored the relationship between methylation, expression of MeDEGs, and survival time. Gene set enrichment analysis (GSEA) was conducted to predict the function of prognosis-related MeDEGs.

Results

A total of nine up-regulated and 72 down-regulated MeDEGs were identified. GO and KEGG pathway analyses results indicated that multiple cancer-related terms were enriched. Kaplan–Meier survival analysis showed that the methylation status of four MeDEGs (CTF1, FZD8, PDK4, and ZNF334) was negatively associated with overall survival. Moreover, the methylation status of CDF1 and PDK4 was identified as an independent prognostic factor. According to GSEA, hypermethylation of prognosis-related MeDEGs was enriched in pathways that included “Spliceosome”, “Cell cycle”, “RNA degradation”, “RNA polymerase”, “DNA replication”, “Mismatch repair”, “Base excision repair”, “Nucleotide excision repair”, “Homologous recombination”, “Protein export”, and “Pyrimidine metabolism”.

Conclusions

Aberrant DNA methylation plays a critical role in malignant progression of HCC. Prognosis-related MeDEGs identified in this research may be potential biomarkers and targets in diagnosis and treatment.

Cardiotrophin-1 determines liver engraftment of syngenic colon carcinoma cells through an immune system-mediated mechanism

Cardiotrophin-1 (CT-1/CTF1) is a member of the interleukin-6 (IL-6) family of cytokines that stimulates STAT-3 phosphorylation in cells bearing the cognate receptor. We report that Ctf1^−/− mice (hereby referred to as CT-1^−/− mice) are resistant to the hepatic engraftment of MC38 colon carcinoma cells, while these cells engraft normally in the mouse subcutaneous tissue. Tumor intake in the liver could be enhanced by the systemic delivery of a recombinant adenovirus encoding CT-1, which also partly rescued the resistance of CT-1^−/− mice to the hepatic engraftment of MC38 cells. Moreover, systemic treatment of wild-type (WT) mice with a novel antibody-neutralizing mouse CT-1 also reduced engraftment of this model. Conversely, experiments with Panc02 pancreatic cancer and B16-OVA melanoma cells in CT-1^−/− mice revealed rates of hepatic engraftment similar to those observed in WT mice. The mechanism whereby CT-1 renders the liver permissive for MC38 metastasis involves T lymphocytes and natural killer (NK) cells, as shown by selective depletion experiments and in genetically deficient mice. However, no obvious changes in the number or cell killing capacity of liver lymphocytes in CT-1^−/− animals could be substantiated. These findings demonstrate that the seed and soil concept to understand metastasis can be locally influenced by cytokines as well as by the cellular immune system.

Preventive Effect of Cardiotrophin-1 Administration before DSS-Induced Ulcerative Colitis in Mice

Ulcerative colitis is a relatively frequent, chronic disease that impacts significantly the patient's quality of life. Although many therapeutic options are available, additional approaches are needed because many patients either do not respond to current therapies or show significant side effects. Cardiotrophin-1 (CT-1) is a cytokine with potent cytoprotective, anti-inflammatory, and antiapoptotic properties. The purpose of this study was to assess if the administration of CT-1 could reduce colon damage in mice with experimental colitis was induced with 5% dextran sulfate sodium (DSS) in the drinking water. Half of the mice received an i.v. dose of CT-1 (200 µg/kg) 2 h before and 2 and 4 days after DSS administration. Animals were followed during 7 days after DSS administration. The severity of colitis was measured by standard scores. Colon damage was assessed by histology and immunohistochemistry. Inflammatory mediators were measured by Western blot and PCR. CT-1 administration to DSS-treated mice ameliorated both the clinical course (disease activity index), histological damage, inflammation (colon expression of TNF-α, IL-17, IL-10, INF IFN-γ, and iNOS), and apoptosis. Our results suggest that CT-1 administration before induction of colitis improves the clinical course, tissue damage, and inflammation in DSS-induced colitis in mice.

Cardiotrophin-1 opposes renal fibrosis in mice: Potential prevention of chronic kidney disease

AIM

Chronic kidney disease is characterized by tubulointerstitial fibrosis involving inflammation, tubular apoptosis, fibroblast proliferation and extracellular matrix accumulation. Cardiotrophin-1, a member of the interleukin-6 family of cytokines, protects several organs from damage by promoting survival and anti-inflammatory effects. However, whether cardiotrophin-1 participates in the response to chronic kidney injury leading to renal fibrosis is unknown.

METHODS

We hypothesized and assessed the potential role of cardiotrophin-1 in a mice model of tubulointerstitial fibrosis induced by unilateral ureteral obstruction (UUO).

RESULTS

Three days after UUO, obstructed kidneys from cardiotrophin-1^-/- mice show higher expression of inflammatory markers IL-1β, Cd68, ICAM-1, COX-2 and iNOs, higher activation of NF-κB, higher amount of myofibroblasts and higher severity of tubular damage and apoptosis, compared with obstructed kidneys from wild-type littermates. In a later stage, obstructed kidneys from cardiotrophin-1^-/- mice show higher fibrosis than obstructed kidneys from wild-type mice. Interestingly, administration of exogenous cardiotrophin-1 prevents the increased fibrosis resulting from the genetic knockout of cardiotrophin-1 upon UUO, and supplementation of wild-type mice with exogenous cardiotrophin-1 further reduces the renal fibrosis induced by UUO. In vitro, renal myofibroblasts from cardiotrophin-1^-/- mice have higher collagen I and fibronectin expression and higher NF-κB activation than wild-type cells.

CONCLUSIONS

Cardiotrophin-1 participates in the endogenous response that opposes renal damage by counteracting the inflammatory, apoptotic and fibrotic processes. And exogenous cardiotrophin-1 is proposed as a candidate for the treatment and prevention of chronic renal fibrosis.

Potential clinical treatment of colitis with cardiotrophin-1

In a recent issue of Clinical Science, Prieto-Vicente et al. [Clin. Sci. (2018) 132, 985-1001] have smartly demonstrated a potential new use of cardiotrophin-1 (CT-1) to treat and palliate an inflammatory bowel disease such as ulcerative colitis. In that work, authors report that in ulcerative colitic mice, administration of exogenous recombinant CT-1 (rCT-1) promotes lower colon damage and lower disease activity index, reducing systemic levels of tumor necrosis factor α (TNF-α) and also diminishing TNF-α expression in colon together with the reduction in other common inflammation markers. Besides, in vivo rCT-1 administration induces activation of several molecular pathways, including nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) and signal transducer and activator of transcription (STAT)-3, and abolishes bacterial translocation from intestine to other organs, including mesenteric ganglia, lungs, and spleen. Additionally, these results were nicely corroborated in CT-1 depleted mice; in which colon damage and ulcerative colitis severity were greater compared with the wild-type counterparts. All together, these results suggested that CT-1 could be a promising new therapeutic approach for treating inflammatory bowel disease, particularly ulcerative colitis. However, further studies are required to determine its major mechanisms of action and the potential efficacy of CT-1 in human inflammatory bowel diseases.

Cardiotrophin-1 attenuates experimental colitis in mice

Cardiotrophin-1 (CT-1) holds potent anti-inflammatory, cytoprotective, and anti-apoptotic effects in the liver, kidneys, and heart. In the present study, the role of endogenous CT-1 and the effect of exogenous CT-1 were evaluated in experimental ulcerative colitis. Colitis was induced in CT-1 knockout and wild-type (WT) mice by administration of dextran sulphate sodium (DSS) in the drinking water during 7 days. CT-1 knockout mice showed higher colon damage and disease severity than WT mice. In addition, CT-1 (200 µg/kg/day, iv) or vehicle (as control) was administered during 3 days to WT, colitic mice, starting on day 4 after initiation of DSS. Disease activity index (DAI), inflammatory markers (tumor necrosis factor α (TNF-α), INFγ, IL-17, IL-10, inducible nitric oxide synthase (iNOS)), colon damage, apoptosis (cleaved caspase 3), nuclear factor κB (NFκB) and STAT-3 activation, and bacterial translocation were measured. Compared with mice treated with DSS, mice also treated with exogenous CT-1 showed lower colon damage, DAI, plasma levels of TNFα, colon expression of TNF-α, INFγ, IL-17, iNOS and cleaved caspase 3, higher NFκB and signal transducer and activator of transcription 3 (STAT3) pathways activation, and absence of bacterial translocation. We conclude that endogenous CT-1 plays a role in the defense and repair response of the colon against ulcerative lesions through an anti-inflammatory and anti-apoptotic effect. Supplementation with exogenous CT-1 ameliorates disease symptoms, which opens a potentially new therapeutic strategy for ulcerative colitis.

Gene expression profile after knockdown of USP18 in Hepg2.2.15 cells

In our previous work, we found that the expression of ubiquitin-specific protease 18 (USP18), also known as UBP43, is associated with the efficiency of interferon alpha (IFN-α) treatment in patients with chronic hepatitis B (CHB). To elucidate the influence of USP18 on hepatitis B virus (HBV) replication and the mechanism of this activity, we silenced USP18 by introducing short hairpin RNA (shRNA) into Hepg2.2.15 cells. To identify the changed genes and pathways in Hepg2.2.15-shRNA-USP18 cells, we performed a microarray gene expression analysis to compare the Hepg2.2.15 stably expressing USP18-shRNA cells versus control cells using the Affymetrix Human Transcriptome Array (HTA) 2.0 microarrays. Microarray analysis indicated that genes involved in regulation of thyroid hormone signaling pathway, complement, and coagulation cascades, PERK-mediated unfolded protein response, and insulin-like growth factor-activated receptor activity were significantly altered after USP18 knockdown for 72 h. Furthermore, genes involved in hepatocyte proliferation, liver fibrosis, such as cell cycle regulatory gene CCND1, were also altered after USP18 knockdown in Hepg2.2.15 cells. In conclusion, USP18 is critical for regulating the replication of HBV in Hepg2.2.15 cells, which suggest that USP18 may be a candidate target for HBV treatment.

Cardiotrophin-1 decreases intestinal sugar uptake in mice and in Caco-2 cells

AIM

Cardiotrophin-1 (CT-1) is a member of the IL-6 family of cytokines with a key role in glucose and lipid metabolism. In the current investigation, we examined the in vivo and in vitro effects of CT-1 treatment on intestinal sugar absorption in different experimental models.

METHODS

rCT-1 effects on α-Methyl-D-glucoside uptake were assessed in everted intestinal rings from wild-type and CT-1(-/-) mice and in Caco-2 cells. rCT-1 actions on SGLT-1 expression in brush border membrane vesicles and the identification of the potential signalling pathways involved were determined by Western blot.

RESULTS

In vivo administration (0.2 mg kg(-1) ) of rCT-1 caused a significant decrease on α-Methyl-D-glucoside uptake in everted intestinal rings from wild-type and CT-1(-/-) mice after short-term and long-term treatments. Similarly, in vitro treatment (1-50 ng mL(-1) ) with rCT-1 reduced α-Methyl-D-glucoside uptake in everted intestinal rings. In Caco-2 cells, rCT-1 treatment (20 ng mL(-1) , 1 and 24 h) lowered apical uptake of α-Methyl-D-glucoside in parallel with a decrease on SGLT-1 protein expression. rCT-1 promoted the phosphorylation of STAT-3 after 5 and 15 min treatment, but inhibited the activation by phosphorylation of AMPK after 30 and 60 min. Interestingly, pre-treatment with the JAK/STAT inhibitor (AG490) and with the AMPK activator (AICAR) reversed the inhibitory effects of rCT-1 on α-Methyl-D-glucoside uptake. AICAR also prevented the inhibition of SGLT-1 observed in rCT-1-treated cells.

CONCLUSIONS

CT-1 inhibits intestinal sugar absorption by the reduction of SGLT-1 levels through the AMPK pathway, which could also contribute to explain the hypoglycaemic and anti-obesity properties of CT-1.

Cardiotrophin-1 therapy prevents gentamicin-induced nephrotoxicity in rats

Aminoglycosides are very effective antibiotics for the treatment of severe infections, but they rank among the most frequent causes of drug-induced nephrotoxicity. Thus, prevention of aminoglycoside nephrotoxicity is an unmet therapeutic objective. Cardiotrophin-1 (CT-1), a member of the IL-6 family of cytokines, has been reported to protect the kidney against toxic and ischemic acute kidney injury (AKI). We have assessed the effect of rat CT-1 in the severity of gentamicin (G)-induced AKI. Groups of male Wistar rats received the following for 6 consecutive days: i) isotonic saline solution (group CONT), ii) G, 150mg/kg/day, i.p. (group G), iii) CT-1, 100μg/kg/day i.v. (group CT-1), or iv) G and CT-1 at the doses described above. The G group showed a manifest AKI characterized by low creatinine clearance, high plasma creatinine and urea levels, increased urinary excretion of proteins, glucose and AKI markers such as N-acetyl-glucosaminidase, neutrophil gelatinase-associated lipocalin, kidney-injury molecule-1 and T-gelsolin, increased kidney levels of CD-68, iNOS, IL-1β and TNF-α, and markedly higher histological renal damage and leukocyte infiltration than the CONT and CT-1 groups. Administration of CT-1 together with G reduced almost all of the above-described manifestations of G-induced AKI. The results of this study have potential clinical application, as CT-1 is near to being used as a drug for organ protection.

Comparison of Intravenous and Oral Hydration in the Prevention of Contrast-Induced Acute Kidney Injury in Low-Risk Patients: A Randomized Trial

AIMS

Contrast-induced acute kidney injury (CI-AKI) is a common cause of renal failure. We evaluated the effectiveness of oral sodium citrate versus intravenous (IV) sodium bicarbonate for CI-AKI prophylaxis as well as their influence on kidney injury biomarkers.

MATERIAL AND METHODS

A randomized, controlled, single-center study including 130 hospitalized patients (62.3% men), who were randomized to receive sodium bicarbonate (1/6 men, 3 ml/kg/h for 1 h; n = 43), oral sodium citrate (75 ml/10 kg divided into 4 doses; n = 43) or nonspecific hydration (n = 44) before contrast administration, was conducted. Serum creatinine and kidney injury biomarkers (cystatin C, neutrophil gelatinase-associated lipocalin, interleukin-8, F2-isoprostanes and cardiotrophin-1 [CT-1]) were assessed.

RESULTS

Incidence of CI-AKI was 9.2% with no differences found between hydration groups: 7.0% in sodium bicarbonate group, 11.6% in oral sodium citrate group and 9.1% in the nonspecific hydration group. Urinary creatinine and urinary CT-1/creatinine ratio decreased 4 h after contrast infusion (p < 0.001), but none of the biomarkers assessed were affected by the treatments.

CONCLUSIONS

There were no differences in hydration with oral sodium citrate and IV sodium bicarbonate for the prophylaxis of CI-AKI. Therefore, oral hydration represents a safe, inexpensive and practical method for preventing CI-AKI in low-risk patients. No effect on biomarkers for kidney injury could be demonstrated.

Chronic administration of recombinant IL-6 upregulates lipogenic enzyme expression and aggravates high-fat-diet-induced steatosis in IL-6-deficient mice

Interleukin-6 (IL-6) has emerged as an important mediator of fatty acid metabolism with paradoxical effects in the liver. Administration of IL-6 has been reported to confer protection against steatosis, but plasma and tissue IL-6 concentrations are elevated in chronic liver diseases, including fatty liver diseases associated with obesity and alcoholic ingestion. In this study, we further investigated the role of IL-6 on steatosis induced through a high-fat diet (HFD) in wild-type (WT) and IL-6-deficient (IL-6^−/−) mice. Additionally, HFD-fed IL-6^−/− mice were also chronically treated with recombinant IL-6 (rIL-6). Obesity in WT mice fed a HFD associated with elevated serum IL-6 levels, fatty liver, upregulation of carnitine palmitoyltransferase 1 (CPT1) and signal transducer and activator of transcription-3 (STAT3), increased AMP kinase phosphorylation (p-AMPK), and downregulation of the hepatic lipogenic enzymes fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD1). The HFD-fed IL-6^−/− mice showed severe steatosis, no changes in CPT1 levels or AMPK activity, no increase in STAT3 amounts, inactivated STAT3, and marked downregulation of the expression of acetyl-CoA carboxylase (ACCα/β), FAS and SCD1. The IL-6 chronic replacement in HFD-fed IL-6^−/− mice restored hepatic STAT3 and AMPK activation but also increased the expression of the lipogenic enzymes ACCα/β, FAS and SCD1. Furthermore, rIL-6 administration was associated with aggravated steatosis and elevated fat content in the liver. We conclude that, in the context of HFD-induced obesity, the administration of rIL-6 might contribute to the aggravation of fatty liver disease through increasing lipogenesis.

Summary: The administration of rIL-6 might contribute to the aggravation of fatty liver disease through increasing lipogenesis in HFD-induced obesity.

A Potential Profibrogenic Role of Biliary Epithelium-Derived Cardiotrophin-1 in Pediatric Cholestatic Liver Disease

As a cytokine of the interleukin-6 family, cardiotrophin-1 (CT-1) has been shown to be an important endogenous protector in liver injury. Our study aimed to investigate the role of CT-1 in liver fibrosis in pediatric cholestatic liver disease (PCLD). CT-1 mRNA and protein expression levels were upregulated in PCLD liver biopsy tissues compared with controls. Immunohistochemistry and confocal microscopy of liver sections showed that CT-1 was predominantly expressed by biliary epithelium cells. Serum CT-1 was elevated significantly in the children with PCLD compared with controls. Serum CT-1 levels exhibited a moderate positive correlation with the Scheuer stage of hepatic fibrosis and serum TB levels and a weak correlation with serum ALP levels. In vitro analysis indicated that LX-2 cells preconditioned with CT-1 exhibited significant increments in proliferation and accumulation of extracellular matrix components, while also positively regulating the STAT3 and p38MAPK pathways. In conclusion, biliary epithelium-derived CT-1 may exert a profibrogenic potential in PCLD.

Common genetic variation in the human CTF1 locus, encoding cardiotrophin-1, determines insulin sensitivity

Aims/Hypothesis

Recently, cardiotrophin-1, a member of the interleukin-6 family of cytokines was described to protect beta-cells from apoptosis, to improve glucose-stimulated insulin secretion and insulin resistance, and to prevent streptozotocin-induced diabetes in mice. Here, we studied whether common single nucleotide polymorphisms (SNPs) in the CTF1 locus, encoding cardiotrophin-1, influence insulin secretion and insulin sensitivity in humans.

Methods

We genotyped 1,771 German subjects for three CTF1 tagging SNPs (rs1046276, rs1458201, and rs8046707). The subjects were metabolically characterized by an oral glucose tolerance test. Subgroups underwent magnetic resonance (MR) imaging/spectroscopy and hyperinsulinaemic-euglycaemic clamps.

Results

After appropriate adjustment, the minor allele of CTF1 SNP rs8046707 was significantly associated with decreased in vivo measures of insulin sensitivity. The other tested SNPs were not associated with OGTT-derived sensitivity parameters, nor did the three tested SNPs show any association with OGTT-derived parameters of insulin release. In the MR subgroup, SNP rs8046707 was nominally associated with lower visceral adipose tissue. Furthermore, the SNP rs1458201 showed a nominal association with increased VLDL levels.

Conclusions

In conclusion, this study, even though preliminary and awaiting further confirmation by independent replication, provides first evidence that common genetic variation in CTF1 could contribute to insulin sensitivity in humans. Our SNP data indicate an insulin-desensitizing effect of cardiotrophin-1 and underline that cardiotrophin-1 represents an interesting target to influence insulin sensitivity.

Hepatoprotective effect by pretreatment with olprinone in a swine partial hepatectomy model

Excessive portal flow to a small remnant liver or small-for-size graft is a primary factor of small-for-size syndrome. We demonstrated that olprinone (OLP), a phosphodiesterase III inhibitor, had a hepatoprotective effect in a rat extended hepatectomy model and a small-for-size liver transplantation model through a modification of the portal venous pressure (PVP). To identify the appropriate dose and duration of treatment for clinical applications, we conducted experiments with a swine partial hepatectomy model. Twenty microminipigs were divided into 4 groups that received the following treatments: (A) saline (control group), (B) OLP at 0.3 μg/kg/minute (preoperative and postoperative administration), (C) OLP at 0.1 μg/kg/minute (preoperative administration), and (D) OLP at 0.3 μg/kg/minute (preoperative administration). The pigs underwent 70% partial hepatectomy. Hemodynamic changes, including changes in PVP, were examined. Liver biopsy was performed 1 and 3 hours after hepatectomy. Blood samples were collected until postoperative day 7 (POD7). In comparison with group A, PVP elevations, periportal edema, and sinusoidal hemorrhaging were attenuated after left Glisson's ligation in groups C and D. Pretreatment with OLP in groups C and D preserved the microstructure of sinusoids and improved the prothrombin activity 1 and 3 hours after hepatectomy. These animals showed better recovery of the remnant liver volume and the plasma disappearance rate of indocyanine green on POD7. In contrast, group B showed exacerbation of liver damage. Measurements of the serum OLP concentration showed that 10 ng/mL OLP was appropriate for a hepatoprotective effect. In conclusion, pretreatment with OLP shows hepatoprotective effects in a swine partial hepatectomy model. OLP may have the potential to ameliorate patients' outcomes after hepatectomy or liver transplantation.

Acute oral toxicity and liver oxidant/antioxidant stress of halogenated benzene, phenol, and diphenyl ether in mice: a comparative and mechanism exploration

The lethal doses (LD50s) of fluorinated, chlorinated, brominated, and iodinated benzene, phenol, and diphenyl ether in mice were ascertained respectively under the consistent condition. The acute toxicity of four benzenes orders in fluorobenzene (FB) < iodobenzene < chlorobenzene≈bromobenzene, that of four phenols orders in 4-iodophenol≈4-bromophenol < 4-chlorophenol (4-MCP) < 4-fluorophenol (4-MFP), and that of four diphenyl ethers orders in 4,4'-iododiphenyl ether < 4,4'-difluorodiphenyl ether < 4,4'-dichlorodiphenyl ether≈4,4'-dibromodiphenyl ether. General behavior adverse effects were observed, and poisoned mouse were dissected to observe visceral lesions. FB, 4-MCP, and 4-MFP produced toxic faster than other halogenated benzenes and phenols, as they had lower octanol-water partition coefficients. Pathological changes in liver and liver/kidney weight changes were also observed. Hepatic superoxide dismutase, catalase activities, and malondialdehyde level were tested after a 28-day exposure, which reflects a toxicity order basically consistent with that reflected by the LD50s. By theoretical calculation and building models, the toxicity of benzene, phenol, and diphenyl ether were influenced by different structural properties.

Cardiotrophin 1 protects beta cells from apoptosis and prevents streptozotocin-induced diabetes in a mouse model

AIMS/HYPOTHESIS

Cardiotrophin 1 (CT-1) is a recently described cytokine originally isolated from the heart where it has been shown to play an important role in apoptotic protection of cardiomyocytes and heart hypertrophy. Its beneficial properties have also been described in other organs such as liver and neuromuscular tissue. In the present study, we investigated whether CT-1 can confer protection against pro-apoptotic stimuli in pancreatic beta cells, and its role in insulin secretion and diabetes development.

METHODS

The effects of CT-1 on apoptosis and function were studied using MIN6B1 cells and freshly isolated murine pancreatic islets. The impact on the development of diabetes was evaluated in Ct1-null (Ct1 (-/-)) mice (the gene Ct1 is also known as Ctf1) using two streptozotocin (STZ)-induced models of diabetes.

RESULTS

CT-1 has a protective effect in MIN6B1 cells and murine islets under the pro-apoptotic stimulus of serum deprivation, which correlates with the expression of B cell lymphoma-extra large, or following exposure to a mixture of cytokines. In addition, CT-1 enhances glucose-stimulated insulin secretion in MIN6B1 cells and this was repressed by inhibitors of phospholipase C. Furthermore, Ct1 (-/-) mice were more prone to develop diabetes, and their glucose tolerance test showed impaired plasma glucose clearance which correlated with decreased pancreatic insulin secretion.

CONCLUSIONS/INTERPRETATION

The results obtained from both in vitro and in vivo experiments show that CT-1 improves beta cell function and survival, and protects mice against STZ-induced diabetes.

Spanish human proteome project: dissection of chromosome 16

The Chromosome 16 Consortium forms part of the Human Proteome Project that aims to develop an entire map of the proteins encoded by the human genome following a chromosome-centric strategy (C-HPP) to make progress in the understanding of human biology in health and disease (B/D-HPP). A Spanish consortium of 16 laboratories was organized into five working groups: Protein/Antibody microarrays, protein expression and Peptide Standard, S/MRM, Protein Sequencing, Bioinformatics and Clinical healthcare, and Biobanking. The project is conceived on a multicenter configuration, assuming the standards and integration procedures already available in ProteoRed-ISCIII, which is encompassed within HUPO initiatives. The products of the 870 protein coding genes in chromosome 16 were analyzed in Jurkat T lymphocyte cells, MCF-7 epithelial cells, and the CCD18 fibroblast cell line as it is theoretically expected that most chromosome 16 protein coding genes are expressed in at least one of these. The transcriptome and proteome of these cell lines was studied using gene expression microarray and shotgun proteomics approaches, indicating an ample coverage of chromosome 16. With regard to the B/D section, the main research areas have been adopted and a biobanking initiative has been designed to optimize methods for sample collection, management, and storage under normalized conditions and to define QC standards. The general strategy of the Chr-16 HPP and the current state of the different initiatives are discussed.

Melatonin attenuates inflammation and promotes regeneration in rabbits with fulminant hepatitis of viral origin

The objective of the present study was to investigate the effect of melatonin on the liver inflammatory and regenerative response in an animal model of fulminant hepatic failure (FHF) of viral origin. Rabbits were experimentally infected with 2×10(4) hemagglutination units of a rabbit hemorrhagic disease virus (RHDV) isolate and received melatonin at two concentrations of 10 or 20mg/kg at 0, 12 and 24hr postinfection. RHDV infection induced an inflammatory response, with increased expression of toll-like receptor 4, high-mobility group box (HMGB)1, interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and C-reactive protein, and decreased expression of decay accelerating factor (DAF/CD55). These effects were significantly reduced by melatonin. Matrix metalloproteinase-9 expression was also lowered in melatonin-treated rabbits. RHDV infection inhibited the hepatic regenerative/proliferative response, with a reduced expression of hepatocyte growth factor (HGF), epidermal growth factor, platelet-derived growth factor (PDGF)-B and vascular endothelial growth factor and their receptors; these responses were prevented by melatonin administration. Melatonin treatment also resulted in reduced expression of phosphorylated Janus kinase and enhanced expression of extracellular mitogen-activated protein kinase (ERK) and signal transducer and activator of transcription (STAT) 3. Our findings show that anti-inflammatory effects and stimulation of regenerative mechanisms contribute to the beneficial effects of melatonin in rabbits with experimental infection by RHDV and support a potential hepatoprotective role of melatonin in FHF.

Cardiotrophin-1 reduces ischemia/reperfusion injury during liver transplant

BACKGROUND

Orthotopic liver transplantation (OLT) is currently the elective treatment for advanced liver cirrhosis and acute liver failure. Ischemia/reperfusion damage may jeopardize graft function during the postoperative period. Cardiotrophin-1 (CT-1) has demonstrated cytoprotective properties in different experimental models of liver injury. There is no evidence to demonstrate its potential use in the prevention of the ischemia/reperfusion injury that occurs during OLT. The present study is the first report to show that the administration of CT-1 to donors would benefit the outcome of OLT.

MATERIALS AND METHODS

We tested the cytoprotective effect of CT-1 administered to the donor prior to OLT in an experimental pig model. Hemodynamic changes, hepatic histology, cell death parameters, activation of cell signaling pathways, oxidative and nitrosative stress, and animal survival were analyzed.

RESULTS

Our data showed that CT-1 administration to donors increased animal survival, improved cardiac and respiratory functions, and reduced hepatocellular injury as well as oxidative and nitrosative stress. These beneficial effects, related to the activation of AKT, ERK, and STAT3, reduced caspase-3 activity and diminished IL-1β and TNF-α expression together with IL-6 upregulation in liver tissue.

CONCLUSIONS

The administration of CT-1 to donors reduced ischemia/reperfusion injury and improved survival in an experimental pig model of OLT.

Acute and subacute oral toxicity of polychlorinated diphenyl sulfides in mice: determining LD50 and assessing the status of hepatic oxidative stress

Polychlorinated diphenyl sulfides (PCDPSs), a series of dioxin-like compounds, have been detected in various environmental samples. However, information on the toxicity of these compounds is limited. In the present study, the toxic effects of PCDPSs were assessed after acute and subacute exposure in mice. Relationships between acute toxicity, number, and position of substituted Cl atoms were assessed. In the acute study, 11 types of PCDPSs were administered to female Kunming mice by gavage, and median lethal doses (LD50s) were determined by the Karber method. Results indicated that the LD50s of lower substituted PCDPSs were smaller than higher substituted PCDPSs. Substituted positions also influenced the LD50 of PCDPSs. Terminal necropsy showed increased relative liver weights and decreased relative kidney weights. Histological examination of livers demonstrated swollen cells, inflammation, vacuolization, and necrosis. In the 28-d subacute exposure tests, 11 types of PCDPSs were dissolved in corn oil and administered to mice at doses of 1, 10, and 100 mg/kg. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels in mouse liver were determined after the exposure period. Results suggested that lower substituted PCDPSs decreased SOD activity in the high-dose groups compared with controls, and MDA level in the 100-mg/kg dose group was significantly increased. In addition, acute toxicity of PCDPSs partly corresponded to the hepatic oxidative damage observed.

Effects of lipoic acid on AMPK and adiponectin in adipose tissue of low- and high-fat-fed rats

BACKGROUND

Lipoic acid (LA) is an antioxidant with antiobesity and antidiabetic properties. Adiponectin is an adipokine with potent anti-inflammatory and insulin-sensitizing properties. AMP-activated protein kinase (AMPK) is a key enzyme involved in cellular energy homeostasis. Activation of AMPK has been considered as a target to reverse the metabolic abnormalities associated with obesity and type 2 diabetes.

AIM OF THE STUDY

The aim of this study was to determine the effects of LA on AMPK phosphorylation and adiponectin production in adipose tissue of low-fat (control diet) and high-fat diet-fed rats.

RESULTS

Dietary supplementation with LA reduced body weight and adiposity in control and high-fat-fed rats. LA also reduced basal hyperinsulinemia as well as the homeostasis model assessment (HOMA) levels, an index of insulin resistance, in high-fat-fed rats, which was in part independent of their food intake lowering actions. Furthermore, AMPK phosphorylation was increased in white adipose tissue (WAT) from LA-treated rats as compared with pair-fed animals. Dietary supplementation with LA also upregulated adiponectin gene expression in WAT, while a negative correlation between adiposity-corrected adiponectin levels and HOMA index was found. Our present data suggest that the ability of LA supplementation to prevent insulin resistance in high-fat diet-fed rats might be related in part to the stimulation of AMPK and adiponectin in WAT.

Liver epithelial cells proliferate under hypoxia and protect the liver from ischemic injury via expression of HIF-1 alpha target genes

BACKGROUND

The remnant liver after extended liver resection is susceptible to ischemic injury, resulting in the failure of liver regeneration and liver dysfunction. The present study is aimed to investigate the protective role of the liver epithelial cells (LEC), a liver progenitor cell, on hepatocytes with ischemia in vitro and in vivo.

METHODS

LECs were isolated from rats and cultured under hypoxic conditions (2% O(2)). The cell viability and intracellular ATP levels were measured. The activation of hypoxia-inducible factor-1α (HIF-1α) was assessed by immunofluorescence. The expression of pyruvate dehydrogenase kinase-1 (PDK-1), stromal cell-derived factor-1 (SDF-1), and chemokine receptor 4 (CXCR4) were measured. Hepatocytes were treated with SDF-1 or LEC-conditioned medium under hypoxia, and cell viability was assessed. Finally, hemorrhagic shock was induced in rats with in vivo induction of endogenous LECs, and liver damage was assessed.

RESULTS

In LECs, but not in hepatocytes, cellular viability and intracellular ATP levels were maintained, and nuclear translocation of HIF-1α and expression of pyruvate dehydrogenase kinase-1 mRNA were increased under hypoxic culture conditions. LECs express SDF-1, and CXCR4 expression was increased in hepatocytes under hypoxia. The survival of hepatocytes under hypoxic condition was significantly increased after treatment with SDF-1 or LEC-conditioned medium. The protective effect of conditioned medium was impaired by CXCR4 antagonists. In vivo induction of endogenous LECs suppressed elevation of serum AST and ALT levels after hemorrhage shock and ischemia-reperfusion.

CONCLUSION

LECs are resistant to hypoxia and have a protective role for hepatocytes against hypoxia. Our results suggest that induction of endogenous LECs protected the liver from lethal insults by paracrine signaling of SDF-1 and differentiation into parenchymal cells.

Role of cardiotrophin-1 in obesity and insulin resistance

Cardiotrophin-1 (CT-1) is a member of the gp130 family of cytokines. In a recent study we examined the metabolic features of ct-1 null mice and the effects on body composition, glucose and lipid metabolism of acute and chronic administration of recombinant CT-1. Our data revealed that CT-1 is a key regulator of energy metabolism with potential applications in the treatment of obesity and the metabolic syndrome. This commentary discusses the significance of these findings in the context of other key studies in the field of obesity and insulin resistance.

EXPRESSION PROFILES OF THE CELL MIGRATION-ASSOCIATED GENES DURING RAT LIVER REGENERATION

Cell migration plays the essential role in embryogenesis, wound healing, immunization, infection, and cancer metastasis. To study actions of cell migration-associated genes in liver regeneration, these genes were obtained by seaching for the related databases and literatures, and comprehensive analysis for the gene expression change during the regenerating process in liver was detected by Rat Genome 230 2.0 array, and identification of the LR-associated genes was through comparing the discrepancy in gene expression between sham operation and partial hepatectomy groups. The initially and totally expressed numbers of these genes in the initial phase of LR, G0/G1 transition, cell proliferation, cell differentiation, and structural-functional reconstruction were 88, 16, 79, 9, and 177, 90, 632, 207, respectively, illustrating that the associated genes triggered their expression mainly in the priming stage, and worked in different phases. Their expression similarity was classified into five groups and their expression patterns were categorized into 38 types, and the overall times of up-regulation and down-regulation were 589 and 427. Based on expression profiles and expression patterns of cell migration-associated genes in LR, it was confirmed that cell migration-associated genes rise in mRNA levels.

Gene therapy of liver diseases: a 2011 perspective

Liver diseases including inherited metabolic disorders, chronic viral hepatitis, liver cirrhosis and primary and metastatic liver cancer constitute a formidable health problem because of their high prevalence and the important limitations of current therapies. Gene therapy, a procedure based on the transfer of therapeutic genes to tissues, has been used since the 1990s as a new approach to treating a number of incurable conditions. After a period of lights and shades recent success in treating several devastating diseases like inherited immune deficiency disorders, beta-thalassemia, or inherited blindness appear to herald a new era where gene therapy can be listed among standard therapy options for a wide variety of human conditions. In this review, we provide information illustrating the potentiality of gene therapy in the management of liver diseases lacking other effective therapies.

Cardiotrophin-1 promotes a high survival rate in rabbits with lethal fulminant hepatitis of viral origin

Rabbit hemorrhagic disease virus (RHDV) causes lethal fulminant hepatitis closely resembling acute liver failure (ALF) in humans. In this study, we investigated whether cardiotrophin-1 (CT-1), a cytokine with hepatoprotective properties, could attenuate liver damage and prolong survival in virus-induced ALF. Twenty-four rabbits were infected with 2 × 10(4) hemagglutination units of RHDV. Twelve received five doses of CT-1 (100 μg/kg) starting at 12 h postinfection (hpi) (the first three doses every 6 h and then two additional doses at 48 and 72 hpi), while the rest received saline. The animals were analyzed for survival, serum biochemistry, and viral load. Another cohort (n = 22) was infected and treated similarly, but animals were sacrificed at 30 and 36 hpi to analyze liver histology, viral load, and the expression of factors implicated in liver damage and repair. All infected rabbits that received saline died by 60 hpi, while 67% of the CT-1-treated animals survived until the end of the study. Treated animals showed improved liver function and histology, while the viral loads were similar. In the livers of CT-1-treated rabbits we observed reduction of oxidative stress, diminished PARP1/2 and JNK activation, and decreased inflammatory reaction, as reflected by reduced expression of tumor necrosis factor alpha, interleukin-1β, Toll-like receptor 4, VCAM-1, and MMP-9. In addition, CT-1-treated rabbits exhibited marked upregulation of TIMP-1 and increased expression of cytoprotective and proregenerative growth factors, including platelet-derived growth factor B, epidermal growth factor, platelet-derived growth factor receptor β, and c-Met. In conclusion, in a lethal form of acute viral hepatitis, CT-1 increases animal survival by attenuating inflammation and activating cytoprotective mechanisms, thus representing a promising therapy for ALF of viral origin.

Treatment of murine fulminant hepatitis with genetically engineered endothelial progenitor cells

BACKGROUND & AIMS

Cell therapy has been used to attenuate liver injury. Here we evaluated whether genetic engineering of either bone marrow-derived mononuclear cells (MNC) or endothelial progenitor cells (EPC) many enhance their hepatoprotective properties.

METHODS

Mice with ConA-induced hepatitis or with lethal fulminant hepatitis resulting from administration of an adenovirus encoding CD40L (AdCD40L) received an intra-splenic injection of saline or 2 × 10(6) unmodified MNC or EPC or the same cells transduced ex vivo with an adenovirus expressing luciferase (MNCLUC and EPCLUC) or encoding the hepatoprotective cytokine cardiotrophin-1 (CT-1) (MNCCT-1 and EPCCT-1). We analyzed the extent of liver damage, the intensity of inflammatory reaction, and animal survival.

RESULTS

Luciferase immunohistochemistry showed that after injection into the spleen, the engineered cells migrated efficiently to the damaged liver. In mice with ConA hepatitis EPCCT-1, but not other forms of cell therapy, significantly decreased serum transaminases and induced more intense histological improvement than other treatments. This superior therapeutic effect was associated with upregulation of cytoprotective molecules including IGF-I and EGF, lower expression of proinflammatory cytokines, IL-1b and TNFα, and decreased granzyme B levels. In AdCD40L-induced lethal fulminant hepatitis, EPCCT-1 also exceeded other cell therapies in attenuating the expression of proinflammatory mediators and hepatic injury enabling 35.7% survival while mortality was 100% in the other treatment groups.

CONCLUSIONS

Genetic engineering of EPC to overexpress CT-1 enhances the hepatoprotective properties of EPC and constitutes a therapy that deserves consideration for acute liver failure.

Cardiotrophin-1 is a key regulator of glucose and lipid metabolism

Cardiotrophin-1 (CT-1) is a member of the gp130 family of cytokines. We observed that ct-1(-/-) mice develop mature-onset obesity, insulin resistance, and hypercholesterolemia despite reduced calorie intake. Decreased energy expenditure preceded and accompanied the development of obesity. Acute treatment with rCT-1 decreased blood glucose in an insulin-independent manner and increased insulin-stimulated AKT phosphorylation in muscle. These changes were associated with stimulation of fatty acid oxidation, an effect that was absent in AMPKα2(-/-) mice. Chronic rCT-1 treatment reduced food intake, enhanced energy expenditure, and induced white adipose tissue remodeling characterized by upregulation of genes implicated in the control of lipolysis, fatty acid oxidation, and mitochondrial biogenesis and genes typifying brown fat phenotype. Moreover, rCT-1 reduced body weight and corrected insulin resistance in ob/ob and in high-fat-fed obese mice. We conclude that CT-1 is a master regulator of fat and glucose metabolism with potential applications for treatment of obesity and insulin resistance.

Signal transducer and activator of transcription 3 in liver diseases: a novel therapeutic target

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that is activated by many cytokines and growth factors and plays a key role in cell survival, proliferation, and differentiation. STAT3 activation is detected virtually in all rodent models of liver injury and in human liver diseases. In this review, we highlight recent advances of STAT3 signaling in liver injury, steatosis, inflammation, regeneration, fibrosis, and hepatocarcinogenesis. The cytokines and small molecules that activate STAT3 in hepatocytes may have therapeutic benefits to treat acute liver injury, fatty liver disease, and alcoholic hepatitis, while blockage of STAT3 may have a therapeutic potential to prevent and treat liver cancer.

Human hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein cures fas-induced acute liver failure in mice by attenuating free-radical damage in injured livers

Acute liver failure (ALF) is a rare syndrome with a difficult clinical management and a high mortality rate. During ALF, several molecular pathways governing oxidative stress and apoptosis are activated to induce massive tissue injury and suppress cell proliferation. There are few anti-ALF drug candidates, among which is the C-type lectin Reg3α, or human hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), which displayed promising properties for tissue regeneration and protection against cellular stress in transgenic mice. We report on substantial preclinical and clinical advances in the development of a recombinant (rc) full-length human HIP/PAP protein as an anti-ALF drug. The curative effects and mechanisms of action of rcHIP/PAP were investigated in murine Fas-induced ALF. Primary hepatocytes were cultured with cytotoxic doses of tumor necrosis factor α/actinomycin-D, transforming growth factor β, agonistic Fas antibody or hydrogen peroxide, and various concentrations of rcHIP/PAP. Cell viability, proliferation index, apoptosis, and oxidation were monitored. We found that rcHIP/PAP significantly improved survival in Fas-intoxicated mice in a dose-dependent and time-dependent manner, with optimum effects when it was injected at advanced stages of ALF. Primary hepatocytes were efficiently protected against multiple cell death signals by rcHIP/PAP. This survival benefit was linked to a depletion of oxidized biomolecules in injured liver cells due to a strong reactive oxygen species scavenging activity of rcHIP/PAP. Clinically, an escalating dose phase 1 trial demonstrated a good tolerability and pharmacokinetic profile of rcHIP/PAP in healthy subjects.

CONCLUSION

The rcHIP/PAP protein exhibited significant curative properties against ALF in mice. It is a free-radical scavenger that targets a broad spectrum of death effectors and favors liver regeneration. The good safety profile of rcHIP/PAP during a phase 1 trial encourages evaluation of its efficacy in patients with ALF.

Olprinone attenuates excessive shear stress through up-regulation of endothelial nitric oxide synthase in a rat excessive hepatectomy model

After extended hepatectomy, excessive shear stress in the remnant liver causes postoperative liver failure. Olprinone (OLP), a selective phosphodiesterase inhibitor, has been reported to improve microcirculation and attenuate inflammation. The aim of this study was to investigate the effects of OLP on shear stress in rats with an excessive hepatectomy (EHx) model. In this study, EHx comprised 90% hepatectomy with ligation of the left and right Glisson's sheaths in Lewis rats. OLP or saline was intraperitoneally administered with an osmotic pump 48 hours before EHx. To evaluate the shear stress, we measured the portal vein (PV) pressure. We also assessed sinusoidal endothelial cell injury by immunohistochemistry and electron microscopy. Furthermore, we assessed apoptosis in the liver with the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling method. Treatment with OLP up-regulated hepatic endothelial nitric oxide synthase (eNOS) expression. The increase in the PV pressure due to Glisson's sheath ligation was attenuated in OLP-treated rats during a 30-minute period after ligation. Treatment with OLP preserved sinusoidal endothelial cells and reduced apoptosis in the remnant liver. The probability of survival in the OLP-treated rats was significantly better than that in the controls (33.3% versus 13.3%). Furthermore, the postoperative eNOS activity in the OLP-treated rats was higher than that in the controls. The administration of Nω-nitro-l-arginine methyl ester to OLP-treated rats eliminated the effects of OLP on PV pressure and survival after EHx. Therefore, we concluded that OLP attenuates excessive shear stress through the up-regulation of eNOS and improves the survival rate after EHx.

Dual effect of erythropoietin on liver protection and regeneration after subtotal hepatectomy in rats

The only currently offered curative option for many patients with primary or secondary liver tumors is the resection of hepatic tumors. The aim of this study was to evaluate the role of recombinant human erythropoietin (rhEPO) in liver protection and regeneration after subtotal hepatectomy in rats. Rats undergoing 70% hepatectomy received an intraperitoneal injection of saline (control) or rhEPO (4 U/g) 30 minutes prior to resection. Liver function was assessed by the measurement of the international normalized ratio (INR) levels, and hepatic injury was assessed by serum alanine aminotransferase and aspartate aminotransferase levels. Hepatic apoptosis was assessed by intrahepatic caspase-3 activity and morphological criteria. The regeneration capacity of remnant livers was assessed over 7 days with the regenerated liver/body weight ratio, immunohistochemistry markers of cell proliferation (Ki-67) and angiogenesis (von Willebrand factor), and phosphorylated extracellular signal-regulated kinase signaling. Two and 4 days after subtotal hepatectomy, the regenerated liver/body weight ratio was significantly higher in animals treated with rhEPO versus the control group (P < 0.005). Serum liver enzymes and INR levels on days 2 and 4 post-hepatectomy were significantly lower in animals pretreated with rhEPO in comparison with the control group (P < 0.005). No statistically significant difference was noted in intrahepatic hepatic caspase-3 activity, immunohistochemistry for caspase-3, or a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling assay between the hepatectomized groups. In the rhEPO-pretreated group, the mitotic index, Ki-67 and von Willebrand factor expression, and extracellular signal-regulated kinase activity were significantly higher on day 2 post-hepatectomy (P < 0.05) in comparison with the control group. In conclusion, rhEPO treatment may offer a unique beneficial dual-function strategy for hepatic protection and regeneration immediately after subtotal hepatectomy in rats.

A novel system for the production of high levels of functional human therapeutic proteins in stable cells with a Semliki Forest virus noncytopathic vector

Semliki Forest virus (SFV) vectors lead to high protein expression in mammalian cells, but expression is transient due to vector cytopathic effects, inhibition of host cell proteins and RNA-based expression. We have used a noncytopathic SFV mutant (ncSFV) RNA vector to generate stable cell lines expressing two human therapeutic proteins: insulin-like growth factor I (IGF-I) and cardiotrophin-1 (CT-1). Therapeutic genes were fused at the carboxy-terminal end of Puromycin N-acetyl-transferase gene by using as a linker the sequence coding for foot-and-mouth disease virus (FMDV) 2A autoprotease. These cassettes were cloned into the ncSFV vector. Recombinant ncSFV vectors allowed rapid and efficient selection of stable BHK cell lines with puromycin. These cells expressed IGF-I and CT-1 in supernatants at levels reaching 1.4 and 8.6 microg/10(6)cells/24 hours, respectively. Two cell lines generated with each vector were passaged ten times during 30 days, showing constant levels of protein expression. Recombinant proteins expressed at different passages were functional by in vitro signaling assays. Stability at RNA level was unexpectedly high, showing a very low mutation rate in the CT-1 sequence, which did not increase at high passages. CT-1 was efficiently purified from supernatants of ncSFV cell lines, obtaining a yield of approximately 2mg/L/24 hours. These results indicate that the ncSFV vector has a great potential for the production of recombinant proteins in mammalian cells.

Acute toxicity and sub-chronic toxicity of steroidal saponins from Dioscorea zingiberensis C.H.Wright in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Steroidal saponins from Dioscorea zingiberensis are widely used in China for curing cardiovascular diseases. However, there was little toxicological information available on them.

AIM OF THE STUDY

The study evaluated potential toxicity of the steroidal saponins and analyzed the metabolites in rats.

MATERIALS AND METHODS

For the acute study, the steroidal saponins were administered to kunming mice in single doses of 112.5-9000 mg/kg given by gavage. General behavior adverse effects, mortality and liver histopathological changes were examined. For the sub-chronic toxicity study, Sprague-Dawley rats were gavaged at doses of 127.5, 255 and 510 mg/kg/day for 30 days, then examined the biochemical and hematological parameters. Metabolites in serum were analyzed by HPLC-MS.

RESULTS

The steroidal saponins caused dose-dependent general behavior adverse effects, mortality and liver histopathological changes in the acute toxicity study. In the sub-chronic toxicity study, 510 mg/kg/day of steroidal saponins increased total bilirubin (TBIL) in serum and decreased protein content in liver significantly. The metabolic process of TBIL in liver includes TBIL intaking, conjugated bilirubin forming, conjugated bilirubin excreting to biliary passage. Treatment with high dose of the steroidal saponins in vivo may lead to vacuolization of the cytoplasm of hepatocytes and canalicular cholestasis. In all doses used in the experiment, the steroidal saponins decreased aspartate aminotransferase (GOT), alanine aminotransferase (ALT) and alkaline phosphatase (AKP) in serum and increased reduced glutathione hormone (GSH), glutathione reductase (GR) and glutathione S-transferases (GST) in liver. Diosgenin was the main metabolite in serum.

CONCLUSIONS

The steroidal saponins did not show any sign of toxicity up to oral dose of 562.5mg/kg in mice. No significant changes of biochemical and hematological parameters in rats (except at 510 mg/kg/day), it was concluded that the steroidal saponins did not appear to have significant toxicity in their traditional uses.

Eicosapentaenoic acid stimulates AMP-activated protein kinase and increases visfatin secretion in cultured murine adipocytes

Visfatin is an adipokine highly expressed in visceral AT (adipose tissue) of humans and rodents, the production of which seems to be dysregulated in excessive fat accumulation and conditions of insulin resistance. EPA (eicosapentaenoic acid), an n-3 PUFA (polyunsaturated fatty acid), has been demonstrated to exert beneficial effects in obesity and insulin resistance conditions, which have been further linked to its reported ability to modulate adipokine production by adipocytes. TNF-alpha (tumour necrosis factor-alpha) is a pro-inflammatory cytokine whose production is increased in obesity and is involved in the development of insulin resistance. Control of adipokine production by some insulin-sensitizing compounds has been associated with the stimulation of AMPK (AMP-activated protein kinase). The aim of the present study was to examine in vitro the effects of EPA on visfatin production and the potential involvement of AMPK both in the absence or presence of TNF-alpha. Treatment with the pro-inflammatory cytokine TNF-alpha (1 ng/ml) did not modify visfatin gene expression and protein secretion in primary cultured rat adipocytes. However, treatment of these primary adipocytes with EPA (200 mumol/l) for 24 h significantly increased visfatin secretion (P<0.001) and mRNA gene expression (P<0.05). Moreover, the stimulatory effect of EPA on visfatin secretion was prevented by treatment with the AMPK inhibitor Compound C, but not with the PI3K (phosphoinositide 3-kinase) inhibitor LY294002. Similar results were observed in 3T3-L1 adipocytes. Moreover, EPA strongly stimulated AMPK phosphorylation alone or in combination with TNF-alpha in 3T3-L1 adipocytes and pre-adipocytes. The results of the present study suggest that the stimulatory action of EPA on visfatin production involves AMPK activation in adipocytes.

Cardiotrophin-1. Review

BACKGROUND

Cardiotrophin-1 is newly discovered chemokin with a lot of functions. Aim of our work was to describe most important of them.

METHODS

systematically scan of available scientific resources.

RESULTS

Cardiotrophin-1 stimulates the proliferation of cardiomyocytes. Cardiotrophin-1 expression and plasma values are elevated in individuals with heart failure and have high diagnostic efficacy for the heart failure. Plasma values are also an independent prognostic factor. Preliminary findings suggest that the determination of plasma cardiotrophin-1 may be useful for the follow-up of hypertensive heart disease in routine clinical practice. Cardiotrophin-1 also plays an important cardioprotective effect on myocardial damage, is a potent regulator of signaling in adipocytes in vitro and in vivo and potentiates the elevation the acute-phase proteins. Cardiotrophin-1 may play also an important protective role in other organ systems (such as hematopoietic, neuronal, developmental).

CONCLUSION

Cardiotrophin is a newly discovered chemokin with a lot of system effects and is stable in system circulation hence permitting its development in the routine clinical investigation.

High-density seedling expression system for the production of bioactive human cardiotrophin-1, a potential therapeutic cytokine, in transgenic tobacco chloroplasts

Histidine-tagged human cardiotrophin-1 (hCT-1), a recently discovered cytokine with excellent therapeutic potential, was expressed in tobacco chloroplasts under the transcriptional and translational control of two different promoters (rrn and psbA) and 5'-untranslated regions (5'-UTRs) (psbA and phage T7 gene 10). The psbA 5'-UTR promotes recombinant hCT-1 (rhCT-1) accumulation in chloroplasts at higher levels (eight-fold) than those obtained for the phage T7 gene 10 5'-UTR, regardless of the promoter used, indicating that the correct choice of translational control element is most important for protein production in chloroplasts. The maximum level of rhCT-1 achieved was 1.14 mg/g fresh weight (equivalent to 5% of total soluble protein) with the psbA promoter and 5'-UTR in young leaves harvested after 32 h of continuous light, although the bioactivity was significantly lower (approximately 35%) than that of commercial hCT-1. However, harvesting in the dark or after 12 h of light did not result in a significant decrease in the bioactivity of rhCT-1, suggesting that 32 h of over-lighting affects the biological activity of rhCT-1. Because high levels of rhCT-1 accumulation took place mainly in young leaves, it is proposed that seedlings should be used in a 'closed system' unit, yielding up to 3.2 kg per year of rhCT-1. This amount would be sufficient to meet the estimated annual worldwide needs of hCT-1 for liver transplantation surgery in a cost-effective manner. Furthermore, our strategy is an environmentally friendly method for the production of plant-based biopharmaceuticals.