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

Dimethyloxalylglycine pretreatment of living donor alleviates both donor and graft liver ischemia-reperfusion injury in rats

Background: Under the circumstance of the increasing waiting list for liver transplantation, living donor liver transplantation (LDLT) can alleviate the shortage of liver donors to some extent. However, how to reduce both donor and graft ischemia-reperfusion injury (IRI) is still an unsolved problem in LDLT. Hypoxia-induced transcription factor 1 (HIF1) activation is considered an important mechanism of cellular adaptation to hypoxia, and early activation of HIF1 may be a new way to alleviate liver IRI. Therefore, we aimed to investigate the impact of the HIF1 stabilizer dimethyloxalylglycine (DMOG) on IRI and the survival rate of donors and recipients of rat LDLT. Methods: Seventy percent partial liver resection and 30% partial liver transplantation were used to simulate donor and recipient of clinical LDLT. Rats were treated with DMOG (40 mg/kg) or with an equivalent amount of saline. The expression of HIF1 and downstream targets was analyzed after 2 h of reperfusion. Liver function and histopathology, apoptosis and oxidative stress levels were detected 6 h after reperfusion. At the same time, the 7-day survival rate of rats was calculated. Results: DMOG pretreatment significantly reduced IR-induced injury in the donor and recipient, which was manifested by reducing liver function damage and promoting tissue recovery. Meanwhile, compared with the untreated group, the oxidative stress level and the cell apoptosis rate were decreased in the group pretreated with DMOG. In addition, the transcription and expression of HIF1 target genes in the DMOG group were significantly enhanced. Remarkably, DMOG also increased the survival rate of the recipient. Conclusion: This study provides the first evidence that DMOG pretreatment of donors significantly alleviates liver IRI in both donors and recipients and increases the survival rate of recipients in LDLT. Therefore, DMOG may be a promising strategy for improving LDLT in the future.

Glycoengineering tobacco plants to stably express recombinant human erythropoietin with different N-glycan profiles

Plant-based expression system has many potential advantages to produce biopharmaceuticals, but plants cannot be directly used to express human glycoproteins because of their differences in glycosylation abilities from mammals. To exploit plant-based expression system for producing recombinant human erythropoietin (rhuEPO), we glycoengineered tobacco plants by stably introducing seven to eight mammalian genes including a target human EPO into tobacco in order to generate capacities for β1,4-galactosylation, bisecting N-acetylglucosamine (GlcNAc) and sialylation. Wild type human β1,4-galactosyltransferase gene (GalT) or a chimeric GalT gene (ST/GalT) was co-expressed to produce rhuEPO bearing β1,4-galactose-extended N-glycan chains as well as compare their β1,4-galactosylation efficiencies. Five mammalian genes encoding enzymes/transporter for sialic acid biosynthesis, transport and transfer were co-expressed to build sialylation capacity in plants. The human MGAT3 was co-expressed to produce N-glycan chains with bisecting GlcNAc. Our results demonstrated that the above transgenes were incorporated into tobacco genome and transcribed. ST/GalT was found to be more efficient than GalT for β1,4-galactosylation. Furthermore, co-expressing MGAT3 generated N-glycans likely bearing bisected GlcNAc. However, our current efforts did not result in generating sialylation capacity. Created transgenic plants expressing EPO and ST/GalT could be used to produce rhuEPO with high proportion of β1,4-galactose-extended N-glycan chains for tissue protective purposes.

Preoperative erythropoietin treatment improves survival following major hepatic resection in a cirrhotic rat model

AIM

Major hepatic resection of a cirrhotic liver may result in a fatal clinical course. Preoperative erythropoietin (EPO) treatment has been shown to have protective properties and to stimulate liver regeneration. This study aims to investigate the effect of preoperative EPO on survival following major hepatic resection in a cirrhotic rat model.

METHODS

Cirrhotic liver was induced by intraperitoneal injection of thioacetamide (200mg/kg/mL) in 72 Lewis rats. Each 36 rats received EPO (1IU/g, every second day, 5 times preoperatively) or saline (control) and major hepatectomy (removal of the left and half of the median lobe) was performed. Biochemical and immunohistochemical parameters, cytokines and overall survival were compared following surgery.

RESULTS

Rats that received preoperative EPO had decreased hepatic aspartate aminotransferase, alanine aminotransferase and interleukin (IL)-1β expression, 48hours following surgery. They had increased hepatocyte growth factor and vascular endothelial growth factor expression at 1hour, increased IL-6 expression at 24, 48 and 120hours and increased Ki-67, 120hours following surgery. Overall, survival was significantly improved among EPO-treated rats (P=0.034).

CONCLUSION

Preoperative EPO treatment has a protective effect and stimulates liver regeneration, leading to improved overall survival following major hepatectomy in a cirrhotic rat model.

The Effect of Geraniol on Liver Regeneration After Hepatectomy in Rats

Geraniol is a monoterpenoid alcohol that has a hepatoprotective effect. We investigated the regenerative effects of geraniol in rats after a 70% partial hepatectomy (PH). Using Wistar albino rats, nine groups were created: Group I was the control group, while the remaining groups received a single intraperitoneal dose of saline, Silymarin, or geraniol after PH. A 70% PH was performed on all groups except for groups II and III. Blood serum samples were obtained for alanine amino transferase (ALT) analysis. Then liver tissues were harvested for histological and real-time polymerase chain reaction (PCR) analyses. Tumor necrosis factor-α (TNFα) and interleukin 6 (IL6) gene expression were examined 24 and 48 h after PH. ALT levels were found to be statistically significantly increased in all PH-treated groups. TNFα and IL6 gene expression levels were elevated in geraniol-treated groups. Histological evaluation revealed a hepatoprotective effect for geraniol-treated groups. Our results suggest that geraniol plays a significant role during liver regeneration, which involves the elevated expression of TNFα and IL6 48 h after PH.

Potential Use of Biological Proteins for Liver Failure Therapy

Biological proteins have unlimited potential for use as pharmaceutical products due to their various biological activities, which include non-toxicity, biocompatibility, and biodegradability. Recent scientific advances allow for the development of novel innovative protein-based products that draw on the quality of their innate biological activities. Some of them hold promising potential for novel therapeutic agents/devices for addressing hepatic diseases such as hepatitis, fibrosis, and hepatocarcinomas. This review attempts to provide an overview of the development of protein-based products that take advantage of their biological activity for medication, and discusses possibilities for the therapeutic potential of protein-based products produced through different approaches to specifically target the liver (or hepatic cells: hepatocytes, hepatic stellate cells, liver sinusoidal endothelial cells, and Kupffer cells) in the treatment of hepatic diseases.

Combination of granulocyte colony-stimulating factor and erythropoietin improves outcomes of patients with decompensated cirrhosis

BACKGROUND & AIMS

Patients with decompensated cirrhosis have significantly reduced survival without liver transplantation. Granulocyte colony-stimulating factor (G-CSF) has been shown to increase survival in patients with acute-on-chronic liver failure, and erythropoietin promoted hepatic regeneration in animal studies. We performed a double-blind, randomized, placebo-controlled trial to determine whether co-administration of these growth factors improved outcomes for patients with advanced cirrhosis.

METHODS

In a prospective study, consecutive patients with decompensated cirrhosis seen at the Institute of Liver and Biliary Sciences, New Delhi (from May 2011 through June 2012) were randomly assigned to groups given subcutaneous G-CSF (5 μg/kg/d) for 5 days and then every third day (12 total doses), along with subcutaneous darbopoietin α(40 mcg/wk) for 4 weeks (GDP group, n = 29), or only placebos (control group, n = 26). All patients also received standard medical therapy and were followed for 12 months. Histology was performed on liver biopsies. The primary end point was survival at 12 months.

RESULTS

Baseline characteristics of patients were comparable; alcohol intake was the most common etiology of cirrhosis. A higher proportion of patients in the GDP group than controls survived until 12 months (68.6% vs 26.9%; P = .003). At 12 months, Child-Turcotte Pugh scores were reduced by 48.6% in the GDP group and 39.1% in the control group, from baseline (P = .001); Model for End Stage Liver Disease scores were reduced by 40.4% and 33%, respectively (P = .03). The need for large-volume paracentesis was significantly reduced in GDP group, compared with controls (P < .05). A lower proportion of patients in the GDP group developed septic shock (6.9%) during follow-up compared with controls (38.5%; P = .005). No major adverse events were observed in either group.

CONCLUSIONS

In a single-center randomized trial, a significantly larger proportion of patients with decompensated cirrhosis given a combination of G-CSF and darbopoietin α survived for 12 months more than patients given only placebo. The combination therapy also reduced liver severity scores and sepsis to a greater extent than placebo. Clinicaltrials.gov ID: NCT01384565.

Liver function and anemia pathogenesis in Iranian traditional medicine

Background:

Nutritional deficiency, bleeding, and inflammation are three main causes of anemia. On the other hand, erythropoietin (EPO) production, iron availability, and a healthy bone marrow are essential for erythropoiesis. Recently, recombinant human erythropoietin (rhEPO) has been used to treat the patients already taking iron supplements. In Iranian traditional medicine literature, much has been written about anemia and its treatment.

Objectives:

This study aimed to review Iranian traditional medicine theories in the treatment of anemia.

Materials and Methods:

In the present study, authors have attempted to find the etiology and pathogenesis of anemia in Iranian traditional Medicine Literature and the views of ancient physicians in this field.

Results:

Our findings proved that Iranian traditional medicine defined anemia as blood humor production dysfunction, which is caused by several reasons mainly hepatic dysfunction. Thus, liver is supposed to be the most important organ in this regard. This will make considering hepatoprotective medicines in anemia even in patients with non-hepatic problems.

Conclusions:

The article presents the relation between anemia and liver dysfunction viewed by Iranian traditional medicine as an important finding in designing a treatment plan. Despite the new findings on the evaluation of liver function (i.e. laboratory tests), it seems that further studies for earlier evaluation of liver function in anemia are highly required.

Expression profiles uncover the relationship between erythropoietin and cell proliferation in rat hepatocytes after a partial hepatectomy

Erythropoietin (EPO) has a beneficial effect on hepatic cell proliferation during liver regeneration. However, the underlying mechanism has not yet been elucidated. To uncover the proliferation response of EPO in rat liver regeneration after partial hepatectomy (PH) at the cellular level, hepatocytes (HCs) were isolated using Percoll density gradient centrifugation. The genes of the EPO-mediated signaling pathway and the target genes of the transcription factor (TF) in the pathway were identified in a pathway and TF database search. Their expression profiles were then detected using Rat Genome 230 2.0 Microarray. The results indicated that the EPO-mediated signaling pathway is involved in 19 paths and that 124 genes participate, of which 32 showed significant changes and could be identified as liver regeneration-related genes. In addition, 443 targets regulated by the TFs of the pathway and 60 genes associated with cell proliferation were contained in the array. Subsequently, the synergetic effect of these genes in liver regeneration was analyzed using the E(t) mathematical model based on their expression profiles. The results demonstrated that the E(t) values of paths 3, 8, 12 and 14-17 were significantly strengthened in the progressing phase of liver regeneration through the RAS/MEK/ERK or PI3K/AκT pathways. The synergetic effect of the target genes, in parallel with target-related cell proliferation, was also enhanced 12-72 h after PH, suggesting a potential positive effect of EPO on HC proliferation during rat liver regeneration. These data imply that the EPO receptor may allow EPO to promote HC proliferation through paths 3, 8, 12 and 14-17, mediating the RAS/MEK/ERK and PI3K/AκT pathways in rat liver regeneration after PH.

Growth factors enhance liver regeneration in acute-on-chronic liver failure

Acute-on-chronic liver failure is a distinct syndrome characterized by a rapid progression of liver disease culminating in organ failure and death. The only definitive treatment is liver transplantation. However, there is a possible element of reversibility and hepatic regeneration if the acute insult can be tided over. Exogenously administered growth factors may stimulate hepatocytes, hepatic progenitor cells and bone marrow-derived cells to supplement hepatic regeneration. The proposed review is intended to provide an in-depth analysis of the individual components of hepatic and bone marrow niches and highlight the growing role of various growth factors in liver regeneration in health and in liver failure.

Erythropoietin increases survival and attenuates fulminant hepatic failure injury induced by D-galactosamine/lipopolysaccharide in mice

BACKGROUND

Liver transplantation is the only therapy of proven benefit in fulminant hepatic failure (FHF). Lipopolysaccharide (LPS), d-galactosamine (GalN)-induced FHF is a well-established model of liver injury in mice. Erythropoietin has a powerful tissue-protective effect in animal models. The aim of this study was to investigate the effect and mechanism of recombinant human erythropoietin (rhEPO) administration in FHF mice.

METHODS

C57BL/6 (n=42) mice were studied in vivo in a fulminant model induced by GalN/LPS. rhEPO was administered 30 min after the induction of FHF. Serum liver enzymes and hepatic tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels were determined. Histologic analysis was performed, and apoptotic cells were identified by immunohistochemistry for caspase-3. Nuclear factor (NF)-κB and c-Jun-N-terminal kinase (JNK) activation were studied using Western blot analysis.

RESULTS

After the induction of FHF, all control mice died within 12 hr of GalN/LPS administration. However, 83% of mice that were administered rhEPO were alive 2 weeks later, and overall survival improved (Kaplan-Meier, P<0.001). The serum liver enzymes, hepatic TNF-α and IL-1β levels, liver histologic injury, and apoptotic hepatocytes were significantly reduced in FHF mice that were administered rhEPO compared with untreated mice. A significant decrease in hepatic NF-κB and JNK activation was noted in FHF rhEPO-treated mice compared with FHF untreated mice.

CONCLUSIONS

The administration of rhEPO brought about increased survival and attenuation of the hepatic injury. This was associated with decreased hepatic NF-κB and JNK activation and thus TNF-α and IL-1β levels. These findings have important implications for the potential use of rhEPO in FHF.

The role of excessive versus acute administration of erythropoietin in attenuating hepatic ischemia-reperfusion injury

Ischemia-reperfusion injury (I/R) is the main cause of primary graft nonfunction. Our aim was to evaluate the effect of excessive versus acute administration of erythropoietin (EPO) in attenuating the hepatic injury induced by I/R in mice. The effect of segmental (70%) hepatic ischemia was evaluated in a transgenic mouse line with constitutive overexpression of human EPO cDNA and in wild-type (WT) mice. Mice were randomly allocated to 5 main experimental groups: (i) WT-sham, (ii) WT ischemia, (iii) WT ischemia + recombinant human erythropoietin (rhEPO), (iv) transgenic-sham, and (v) transgenic ischemia. The EPO-pretreated mice showed a significant reduction in liver enzyme levels and intrahepatic caspase-3 activity and fewer apoptotic hepatocytes (p < 0.05 for all) compared with the WT untreated I/R group. EPO decreased c-Jun N-terminal kinase (JNK) phosphorylation and nuclear factor-κB (NF-κB) expression during I/R. In transgenic I/R livers, baseline histology showed diffused hepatic injury, and no significant beneficial effect was noted between the WT untreated and the transgenic I/R mice. In conclusion, acute pretreatment with EPO in WT mice attenuated in vivo I/R liver injury. However, in excessive EPO overexpression, the initial liver injury abolished the beneficial effect of EPO. These findings have important implications for the potential use of acute EPO in I/R injury during liver transplantation.