Transcriptomic and bioinformatics analysis of the mechanism by which erythropoietin promotes recovery from traumatic brain injury in mice

Recent studies have found that erythropoietin promotes the recovery of neurological function after traumatic brain injury.However,the precise mechanism of action remains unclea r.In this study,we induced moderate traumatic brain injury in mice by intrape ritoneal injection of erythro poietin for 3 consecutive days.RNA sequencing detected a total of 4065 differentially expressed RNAs,including 1059 mRNAs,92 microRNAs,799 long non-coding RNAs,and 2115circular RNAs.Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses revealed that the coding and non-coding RNAs that were differentially expressed after traumatic brain injury and treatment with erythropoietin play roles in the axon guidance pathway,Wnt pathway,and MAPK pathway.Constructing competing endogenous RNA networks showed that regulatory relationship between the differentially expressed non-coding RNAs and mRNAs.Because the axon guidance pathway was repeatedly enriched,the expression of Wnt5a and Ephb6,key factors in the axonal guidance pathway,was assessed.Ephb6 expression decreased and Wnt5a expression increased after traumatic brain injury,and these effects were reversed by treatment with erythro poietin.These findings suggest that erythro poietin can promote recove ry of nerve function after traumatic brain injury through the axon guidance pathway.

Evaluation of Hemoglobin and Serum Erythropoietin Levels in Patients with Polycythemia Vera and Secondary Polycythemia

Objective: This study compares hemoglobin and erythropoietin levels in patients with polycythemia vera and secondary polycythemia. Study Design: A retrospective cross-sectional study evaluating the serum erythropoietin and hemoglobin levels in patients with polycythemia vera and secondary polycythemia. This study was performed simultaneously in Texas state of the U.S. and Fars Province in Iran. Methods: Hemoglobin, hematocrit and erythropoietin test results were collected from patients aged 19 to 75 years who were diagnosed with polycythemia vera and secondary polycythemia. Patients records with history of thrombocythemia, congestive heart failure, dyspnea, anemia and pregnant woman were excluded from study. Patients in each decade of life were examined in separate groups, so that changes in hemoglobin related to aging did not affect the research results. Results: 75% of the patients were men, and 25% were women. A total of 1580 patients were analyzed in this study. 57.3% of patients in UTMB and 38.8 patients in Iran have hemoglobin level above 17 mg/dl. 74% of patients in UTMB and 88% of patients in Iran have erythropoietin below 10 IU/mL. Polycythemia in UTMB was more common in people over 50 and in Iran in patients under 50 years old. The serum hemoglobin and erythropoietin levels in patients with polycythemia vera were not significantly different in compare to secondary polycythemia patients. Data showed that there were 84 polycythemia patients per 100,000 people. The results of this study in UTMB and Iran showed that 4.5% and 7%, respectively, of patients with polycythemia had a positive JAK2 test. Conclusion: Low erythropoietin levels may not be helpful in differentiating polycythemia vera from secondary polycythemia. .

Erythropoietin inhibits ferroptosis and ameliorates neurological function after spinal cord injury

Ferroptosis is one of the critical pathological events in spinal cord injury.Erythropoietin has been reported to improve the recovery of spinal cord injury.However,whether ferroptosis is involved in the neuroprotective effects of erythropoietin on spinal cord injury has not been examined.In this study,we established rat models of spinal cord injury by modified Allen’s method and intraperitoneally administered 1000 and 5000 IU/kg erythropoietin once a week for 2 successive weeks.Both low and high doses of erythropoietin promoted recovery of hindlimb function,and the high dose of erythropoietin led to better outcome.High dose of erythropoietin exhibited a stronger suppressive effect on ferroptosis relative to the low dose of erythropoietin.The effects of erythropoietin on inhibiting ferroptosis-related protein expression and restoring mitochondrial morphology were similar to those of Fer-1(a ferroptosis suppressor),and the effects of erythropoietin were largely diminished by RSL3(ferroptosis activator).In vitro experiments showed that erythropoietin inhibited RSL3-induced ferroptosis in PC12 cells and increased the expression of xCT and Gpx4.This suggests that xCT and Gpx4 are involved in the neuroprotective effects of erythropoietin on spinal cord injury.Our findings reveal the underlying anti-ferroptosis role of erythropoietin and provide a potential therapeutic strategy for treating spinal cord injury.

Outbreak of methanol-induced optic neuropathy in early COVID-19 era;effectiveness of erythropoietin and methylprednisolone therapy

BACKGROUND Methanol is a highly toxic,non-potable alcohol.Outbreaks of methanol toxicity occur due to its fraudulent addition to alcoholic beverages as a cheaper substitute for ethanol.Recently,alongside the coronavirus disease 2019(COVID-19)pandemic,rumors circulated on social media that consuming alcohol can prevent or cure the virus,leading to a COVID-19 and methanol-induced optic neuropathy(MON)syndemic.AIM To investigate the impact of erythropoietin(EPO)on the outcomes of patients diagnosed with MON.METHODS In this prospective study,105 patients presenting with acute bilateral visual loss secondary to methanol intoxication were enrolled from March to May 2020 at Farabi Eye Hospital.A comprehensive ocular examination was conducted for all participants.Recombinant human EPO and methylprednisolone were administered intravenously to all patients for three consecutive days.RESULTS The mean age of the participants was 39.9 years(±12.6).Ninety-four patients were male and eleven were female.The mean pre-treatment best corrected visual acuity(BCVA)improved from 2.0±0.86 to 1.39±0.69 logarithm of the minimum angle of resolution post-treatment(P<0.001),with significant improvement observed in all age categories and genders(P<0.001).Visual acuity improvement was also significant regardless of whether the patient presented before or after 72 h(P<0.001),and the post-treatment BCVA remained significant at all monthly follow-up visits(P<0.001).CONCLUSION EPO and methylprednisolone therapy have been shown to be effective in improving visual outcomes in patients with MON when administrated within the first month of exposure.Public awareness efforts are necessary to prevent further outbreaks of methanol toxicity in the current COVID-19 era.

Impact of erythropoietin therapy on cardiorenal syndrome:A systematic review with meta-analysis

BACKGROUND Heart and kidney dysfunction frequently coexist in patients with acute heart failure due to the overlap between these two organ systems.Cardiorenal syndrome(CRS)results from pathology occurring in the heart and kidneys along with the consequences of dysfunction in one organ contributing to dysfunction in the other and vice versa.AIM To evaluate the use of erythropoietin(EPO)in patients with CRS and its effects on hemoglobin(Hb),major cardiovascular(CV)events,and hospitalization rates.METHODS On February 24,2022,searches were conducted using PubMed,MEDLINE,and EMBASE,and 148 articles were identified.A total of nine studies were considered in this systematic review.We assessed the included articles based on the National Heart,Lung,and Blood Institute quality assessment tools for controlled intervention and observational cohort or cross-sectional studies.An assessment of bias risk was conducted on the chosen studies,and data relevant to our review was extracted.RESULTS The systematic review of these studies concluded that most existing literature indicates that EPO improves baseline Hb levels and decreases myocardial remodeling and left ventricular dysfunction without reducing CV mortality.In addition,the effect of EPO on the hospitalization rate of patients with CRS needs to be further studied since this relationship is unknown.Future studies,such as randomized controlled clinical trials and prospective cohort studies,should be conducted to enhance the literature on the potential of EPO therapy in patients with CRS.CONCLUSION Our systematic review suggests that EPO therapy may have a significant role in managing CRS.The review highlights the potential benefits of EPO in improving baseline Hb levels,reducing the risk of major CV events,improving cardiac remodeling,myocardial function,New York Heart Association class,and B-type natriuretic peptide levels.However,the effect of EPO treatment on hospitalization remains unclear and needs further exploration.

Cell-Based Biological Markers for Blood-Enriching Chinese Herbs: Erythropoietin Production in HepG2 Cells and Nitric Oxide Release in Human Umbilical Vein Endothelial Cells (HUVECs)

Chinese tonifying herbs, which are classified into four functional categories (namely, Yang, Qi, Yin, Blood) are commonly used for restoring normal body function and the prevention of diseases. To explore cell-based biological markers for Blood-enriching Chinese herbs, we investigate the effect of 11 commonly used Blood-enriching herbs on erythropoietin (EPO) production in HepG2 cells. Herbs for nourishing Yin were tested for determining the specificity of Blood-enriching herbs in inducing EPO production. In addition, the effects of Blood-enriching herbs on nitric oxide (NO) production in both HepG2 cells and human umbilical vein endothelial cells (HUVECs) were also investigated. The results indicated that methanolic extracts of Blood-enriching herbs (but not Yin-nourishing herbs) showed characteristic pharmacological activity in inducing EPO production in HepG2 cells and NO release in HUVECs. The experimental findings, therefore, support the use of cell-based EPO production and NO release as biological markers for Blood-enriching Chinese tonifying herbs.

Desferoxamine preconditioning protects against cerebral ischemia in rats by inducing expressions of hypoxia inducible factor 1α and erythropoietin

Objective To investigate whether desferoxamine （DFO） preconditioning can induce tolerance against cerebral ischemia and its effect on the expression of hypoxia inducible factor 1 α （HIF- 1α） and erythropoietin （EPO） in vivo and in vitro. Methods Rat model of cerebral ischemia was established by middle cerebral artery occlusion with or without DFO administration. Infarct size was examined by TTC staining, and the neurological severity score was evaluated according to published method. Cortical neurons were cultured under ischemia stress which was mimicked by oxygen-glucose deprivation （OGD）, and the neuron damage was assessed by MTT assay. Immunofluorescent staining was employed to detect the expressions of HIF-1 and EPO. Results The protective effect induced by DFO （decreasing the infarction volume and ameliorating the neurological function） appeared at 2 d after administration ofDFO （post-DFO）, lasted until 7 d and disappeared at 14 d （P 〈 0.05）; the most effective action was observed at 3 d post-DFO. DFO induced tolerance of cultured neurons against OGD： neuronal viability was increased 23%, 34%, 40%, 48% and 56% at 8 h, 12 h, 24 h, 36 h, and 48 h, respectively, post-DFO （P 〈 0.05）. Immunofluorescent staining found that HIF-1 α and EPO were upregulated in the neurons of rat brain at 3 d and 7 d post-DFO; increase of HIF-1 α and EPO appeared in cultured cortex neurons at 36 h and 48 h post-DFO. Conclusion DFO induced tolerance against focal cerebral ischemia in rats, and exerted protective effect on OGD cultured cortical neurons. DFO significant induced the expression of HIF- 1 α and EPO both in vivo and in vitro. DFO preconditioning can protect against cerebral ischemia, which may be associated with the synthesis of HIF- 1 α and EPO.

Neuroprotective effects of erythropoietin on neurodegenerative and ischemic brain diseases: the role of erythropoietin receptor

Erythropoietin （Epo） is a fundamental hormone in the regulation of hematopoiesis, and other secondary roles mediated by the binding of the hormone to its specific receptor （EpoR）, which leads to an activation of key signaling pathways that induce an increase in cell differentiation, apoptosis control and neuroprotection. It has been suggested that their ftmction depends on final conformation of glycosylations, related with affinity to the receptor and its half-life. The presence of EpoR has been reported in different tissues including central nervous system, where it has been demonstrated to exert a neuroprotective function against oxidative stress conditions, such as ischemic injury and neurodegenerative diseases. There is also evidence of an increase in EpoR expression in brain cell lysates of Alzheimer＇s patients with respect to healthy patients. These results are related with extensive in vitro experimental data of neuroprotection obtained from cell lines, primary cell cultures and hippocampal slices. Additionally, this data is correlated with in vivo experiments （water maze test） in mouse models of Alzheimer＇s disease where Epo treatment improved cognitive function. These stud- ies support the idea that receptor activation induces a neuroprotective effect in neurodegenerative disorders including dementias, and especially Alzheimer＇s disease. Taken together, available evidence suggests that Epo appears to be a central element for EpoR activation and neuroprotective properties in the central nervous system. In this review, we will describe the mechanisms associated with neuroprotection and its relation with the activation of EpoR in order with identify new targets to develop pharmacological strategies.

Erythropoietin -induced proliferation of gastric mucosal cells

AIM： To analyze the localization of erythropoietin receptor on gastric specimens and characterize the effects of erythropoietin on the normal gastric epithelial proliferation using a porcine gastric epithelial cell culture model. METHODS： Erythropoietin receptor was detected by RT-PCR, Western blotting and immunohistochermistry. Growth stimulation effects of erythropoietin on cultured gastric mucosal cells were determined by ELISA using bromodeoxyuridine （BrdU）. RESULTS： Erythropoietin receptor was detected on cultured porcine gastric mucosal epithelial cells. Erythropoietin receptor was also detected histochemically at the base of gastric mucosal epithelium. BrdU assay demonstrated a dose-dependent increase in growth potential of cultured porcine gastric mucosal epithelial cells by administration of erythropoietin, as well as these effects were inhibited by administration of antierythropoietin antibody （P〈 0.01）. CONCLUSION： These findings indicate that erythropoietin has a potential to proliferate gastric mucosal epithelium via erythropoietin receptor.

Protective effect of erythropoietin against 1-methyl-4-phenylpyridinium-induced neurodegenaration in PC12 cells

Objective The neuroprotective effect of erythropoietin （EPO） against 1-methyl-4-phenylpyridinium （MPP^＋）- induced oxidative stress in cultured PC12 cells, as well as the underlying mechanism, were investigated. Methods PC12 ceils impaired by MPP^＋ were used as the cell model of Parkinson＇s disease. Methyl thiazolyl tetrazolium （MTT） was used to assay the viability of the PC12 cells exposed to gradient concentrations of EPO, and the terminal deoxynucleotidyl transferase dUTP nick end labelling （TUNEL） assay was used to analyze the apoptosis ratio of PC 12 cells. The expression of Bcl-2 and Bax in PC 12 cells were examined by Western blot, and the reactive oxygen species （ROS）, the mitochondrial transmembrane potential and the activity of caspase-3 in each group were detected by spectrofluorometer. Results Treatment of PC12 cells with MPP^＋ caused the loss of cell viability, which may be associated with the elevation in apoptotic rate, the formation of ROS and the disruption of mitochondrial transmembrane potential. It was also shown that MPP＋ significantly induced the upregulation of Bax/Bcl-2 ratio and the activation of caspase-3. In contrast, EPO significantly reversed these responses and had the maximum protective effect at 1 U/mL. Conclusion The inhibitive effect of EPO on the MPP^＋ -induced cytotoxicity may be ascribed to its anti-oxidative property and anti-apoptotic activity, and EPO may provide a useful therapeutic strategy for treatment of neurodegenerative diseases such as Parkinson＇s disease.

Carbamylated Erythropoietin Alleviates Kidney Damage in Diabetic Rats by Suppressing Oxidative Stress

The oxidative stress response plays an important role in the occurrence and development of diabetic kidney disease(DKD).It has become a new treatment target for DKD.In the current study,the effects of carbamylated erythropoietin(CEPO)on renal oxidative stress and damage in diabetic rats were examined.Thirty Sprague Dawley rats were intraperitoneally administered with 60 mg/kg streptozotocin to establish the diabetes model.The diabetic rats were randomly allocated into 4 groups(n=6 each):diabetes model group(DM group),DM+CEPO treatment group(DC group),DM+CEPO+EPO receptor(EPOR)blocking peptide treatment group(DCEB group),and DM+CEPO+CD131 blocking peptide treatment group(DCCB group).Meanwhile,a normal control group(NC group,n=6)was set up.Kidney tissues and blood samples were obtained for evaluation of oxidative stress and renal function.The results showed that diabetic rats exhibited increased oxidative stress in the kidney and early pathological changes associated with DKD.Treatment with CEPO reduced oxidative stress and attenuated renal dysfunction.However,diabetic rats treated with the combination of CEPO and EPOR blocking peptide or CD131 blocking peptide showed increased oxidative stress and reduced renal function when compared with CEPO treatment alone group.These results suggested that CEPO can protect against kidney damage in DKD by inhibiting oxidative stress injury via EPOR-CD131 heterodimers.

Neurotherapeutic potential of erythropoietin after ischemic injury of the central nervous system

Erythropoietin (EPO) is one of the most successful biopharmaceuticals in history and is used for treating anemia of different origins. However, it became clear that EPO could also work in a neuroprotective, antiapoptotic, antioxidative, angiogenetic and neurotropic way. It causes stimulation of cells to delay cell apoptosis, especially in the central nervous system. In rodent models of focal cerebral ischemia, EPO showed an impressive reduction of infarct size by 30% and improvement of neurobehavioral outcome by nearly 40%. A large animal model dealing with ischemia and reperfusion of the spinal cord showed that EPO could reduce the risk of spinal cord injury significantly. In addition, some clinical studies tested whether EPO works in real live clinical settings. One of the most promising studies showed the innocuousness and improvements in follow-up, outcome scales and in infarct size, of EPO-use in humans suffering from ischemic stroke. Another study ended unfortunately in a negative outcome and an increased overall death rate in the EPO group. The most possible reason was the involvement of patients undergoing simultaneously systemic thrombolysis with recombinant tissue plasminogen activator. An experimental study on rats demonstrated that administration of EPO might exacerbate tissue plasminogen activator-induced brain hemorrhage without reducing the ischemic brain damage. This case shows clearly how useful animal models can be to check negative side effects of a treatment before going into clinical trials. Other groups looked in human trials at the effects of EPO on the outcome after ischemic stroke, relation to circulating endothelial progerdtor cells, aneurysmal subarachnoid hemorrhage, traumatic brain injury, hemoglobin transfusion thresholds and elective first-time coronary artery bypass surgery. Most of the results were pos-让ive, but are based mostly on small group sizes. However, some of the most neglected facts when focusing on experimental setups of ischemia of the central nervous system are issues like age and comorbidities. It might be extremely worthy to consider these points for future projects, because EPO might influence all these factors.

Erythropoietin ameliorates early ischemia-reperfusion injury following the Pringle maneuver

AIM:To investigate the protective effect of erythropoietin (Epo) against ischemia-reperfusion injury (IR/I) following the Pringle maneuver (PM),in comparison with conventional steroid administration in a prospective randomized trial. METHODS:Patients were randomized by age, sex, diagnosis, and surgical method, and assigned to three groups:(1) A steroid group (STRD, n= 9) who received 100 mg of hydrocortisone before PM, and on postoperative days 1, 2 and 3, followed by tapering until postoperative day 7; (2) An EPO1 group (n=10) who received 30 000 U of Epo before the PM and at the end of surgery; and (3) An EPO2 group (n=8) who received 60 000 U of Epo before the PM. Hemoglobin (Hb), hematocrit (Ht), aspartate aminotransferase (AST), alanine transaminase (ALT),lactate dehydrogenase (LDH), lactate, interleukin-6 (IL-6),and tumor necrosis factor(TNF)-α were measured before and just after (Day 0) surgery, and on postoperative days 1, 3, 7 and 14. RESULTS: There were no increases in Hb and Ht in the EPO1 and EPO2 groups. AST was signif icantly lower in EPO1 than in STRD on Day 0 (P=0.041), and lower in EPO1 than in STRD and EPO2 on Day 1 (P=0.018). ALT was signif icantly lower in EPO1 than in STRD and EPO2 on Day 0 (P=0.020) and Day 1 (P=0.004). There were no signif icant inter-group differences in the levels of LDH and lactate. IL-6 was signif icantly lower in EPO1 than in STRD and EPO2 on Day 0 (P=0.0036) and Day 1 (P=0.0451). TNF-α was signif icantly lower in EPO1 than in STRD and EPO2 on Day 0 (P=0.0006) and Day 1 (P<0.0001). Furthermore, hospitalization was signif icantly shorter in EPO1 and EPO2 than in STRD.CONCLUSION:Epo has greater potential than steroids to ameliorate IR/I after the PM. Epo at a dose of 30000 U, administered before PM and just after surgery, yields better results.

Erythropoietin reduces apoptosis of brain tissue cells in rats after cerebral ischemia/reperfusion injury:a characteristic analysis using magnetic resonance imaging

Some in vitro experiments have shown that erythropoietin （EPO） increases resistance to apoptosis and facilitates neuronal survival follow- ing cerebral ischemia. However, results from in vivo studies are rarely reported. Perfusion-weighted imaging （PWI） and diffusion-weighted imaging （DWI） have been applied successfully to distinguish acute cerebral ischemic necrosis and penumbra in living animals; therefore, we hypothesized that PWI and DWI could be used to provide imaging evidence in vivo for the conclusion that EPO could reduce apoptosis in brain areas injured by cerebral ischemia/reperfusion. To validate this hypothesis, we established a rat model of focal cerebral ischemia/ reperfusion injury, and treated with intra-cerebroventricular injection of EPO （5,000 U/kg） 20 minutes before injury. Brain tissue in the ischemic injury zone was sampled using MRI-guided localization. The relative area of abnormal tissue, changes in PWI and DWI in the ischemic injury zone, and the number of apoptotic cells based on TdT-mediated dUTP-biotin nick end-labeling （TUNEL） were assessed. Our findings demonstrate that EPO reduces the relative area of abnormally high signal in PWI and DWI, increases cerebral blood volume, and decreases the number of apoptotic cells positive for TUNEL in the area injured by cerebral ischemia/reperfusion. The experiment pro- vides imaging evidence in vivo for EPO treating cerebral ischemia/reperfusion injury.

Neuroprotection of Erythropoietin and Methylprednisolone against Spinal Cord Ischemia-Reperfusion Injury

Recent research based on various animal models has shown the neuroprotective effects of erythropoietin （EPO）. However, few studies have examined such effects of EPO in the clinic. In this study we enrolled patients with spinal cord ischemia-reperfusion （I-R） injury to investigate the clinical application of EPO and methylprednisolone （MP） for the neuroprotection against spinal cord I-R injury. Retrospective analysis of 63 cases of spinal cord I-R injury was performed. The Frankel neurological performance scale was used to evaluate the neurological function after spinal cord injury （SCI）, including 12 cases of scale B, 30 cases of scale C, and 21 cases of scale D. These cases were divided into 2 groups： group A （27 cases） got treatment with both EPO and MP; group B （36 cases） got treatment with MP only. The neurological function of patients after treatment was evaluated by American Spinal Cord Injury Association （ASIA） index score, and activity of daily living （ADL） of the patients was also recorded. All patients got follow-up and the follow-up period ranged from 24 to 39 months （mean 26 months）. There was no significance difference in neurological function between groups A and B before the treatment （P〉0.05）. However, the neurological function and ADL scores were significantly improved 1 week, 1 year or 2 years after the treatment compared to those before the treatment （P〈0.05）, and the improvement was more significant in group A than in group B （P〈0.05）. It is suggested that the clinical application of EPO and MP provides the neuroprotection against spinal cord I-R injury.

Transplantation of erythropoietin gene-modified neural stem cells improves the repair of injured spinal cord

The protective effects of erythropoietin on spinal Here, the eukaryotic expression plasmid pcDNA3.1 cord injury have not been well described. human erythropoietin was transfected into rat neural stem cells cultured in vitro. A rat model of spinal cord injury was established using a free falling object. In the human erythropoietin-neural stem cells group, transfected neural stem cells were injected into the rat subarachnoid cavity, while the neural stem cells group was inject- ed with non-transfected neural stem cells. Dulbecco＇s modified Eagle＇s medium/F12 medium was injected into the rats in the spinal cord injury group as a control. At 1-4 weeks post injury, the motor function in the rat lower limbs was best in the human erythropoietin-neural stem ceils group, followed by the neural stem cells group, and lastly the spinal cord injury group. At 72 hours, compared with the spinal cord injury group, the apoptotic index and Caspase-3 gene and protein expressions were apparently decreased, and the bd-2 gene and protein expressions were noticeably increased, in the tissues surrounding the injured region in the human erythro- poietin-neural stem cells group. At 4 weeks, the somatosensory evoked potential latencies were cavities were clearly smaller and the motor and remarkably shorter in the human erythropoi- etin-neural stem cells group and neural stem cells group than those in the spinal cord injury group. These differences were particularly obvious in the human erythropoietin-neural stem cells group. More CM-Dil-positive cells and horseradish peroxidase-positive nerve fibers and larger amplitude motor and somatosensory evoked potentials were found in the human erythro- poietin-neural stem cells group and neural stem cells group than in the spinal cord injury group. Again, these differences were particularly obvious in the human erythropoietin-neural stem cells group. These data indicate that transplantation of erythropoietin gene-modified neural stem cells into the subarachnoid cavity to help repair spinal cord injury and promote the recovery of spinal cord function better than neural stem cell transplantation alone. These findings may lead to significant improvements in the clinical treatment of spinal cord injuries.

Pretreatment with erythropoietin reduces hepatic ischemia-reperfusion injury

BACKGROUND: During hepatectomy, a period of ischemia and restoration of the blood supply can result in hepatic ischemia-reperfusion injury (IRI). Current research indicates that erythropoietin (EPO) has a protective effect in animal models of cerebral ischemia, myocardial infarction, and renal IRI. However there is lack of research into the role of EPO in hepatic IRI. This study aimed to explore the role of EPO in hepatic IRI and its possible mechanism of action. METHODS: Thirty male Sprague-Dawley rats were divided into three groups: (1) ten rats in the experimental group were given 1000 IU/kg EPO one day before the operation; (2) ten rats in a control group were given normal saline preoperatively as a placebo; and (3) ten rats served as a sham-operated group. Hepatic IRI was induced by occluding the hepatic arteries of the three cephalad hepatic segments and the portal vein for about 45 minutes, while in the sham-operated group only laparotomy was performed. The levels of ALT and AST were tested 24 hours pre- and post-operation. All rats were sacrificed 24 hours after the operation to assess the pathologic changes in the liver and measure the expression of heme oxygenase-1 (HO-1) through Western blotting and RT-PCR. RESULTS: Hepatic IRI was markedly mitigated in the experimental group as compared with the control group. Moreover, the expression of HO-1 at the level of both transcription and protein increased prominently (P<0.05) in the experimental group. CONCLUSION: These results demonstrate that EPO can up-regulate HO-1 in liver tissues and accordingly decrease hepatic injury through its anti-inflammatory property. (Hepatobiliary Pancreat Dis Int 2009; 8: 294-299)

Effects of erythropoietin on the expression of tumor necrosis factor-alpha and Bax after facial nerve axotomy in rats

This study sought to evaluate the effect of high-dose erythropoietin （EPO; 5 000 IU/kg） on the expression of tumor necrosis factor-alpha （TNF-α） and Bax in the facial nucleus after facial nerve transection in rats. A total of 42 Wistar rats of both genders were used in this study, and 40 rats were randomly divided into 2 groups： EPO group and model group. The EPO group was treated with EPO once a day for 5 days at a dose of 5 000 IU/kg body weight. The model group was treated with saline of the same amount. At day 3 after EPO （or saline） treatment, the right facial nerves of the 40 rats were transected at the level of the stylomastoid foramen, with the left sides untreated. The remaining 2 rats that did not undergo axotomy served as the control group. The surviving motor neurons in operated rats were counted in coronal paraffin sections of the facial nucleus. The expression of TNF-a and Bax in the facial nucleus was detected by immunohistochemical staining at days 3, 7, 14, 21, and 28 after axotomy. At days 14, 21, and 28 after facial nerve axotomy, a significantly greater proportion of facial motor neurons survived in the EPO group than in the model group. After axotomy, the expression of TNF-a and Bax increased in motor neurons in both the EPO and the model groups. TNF-o expression reached its peak level at day 14 after axotomy, while Bax expression reached its peak level at day 21. TNF-α expression was much lower in the EPO group than in the model group at all time points. No significant difference in Bax expression was found between the EPO and the model groups. These results indicate that high-dose EPO treatment attenuates the increase in TNF-α expression in the facial nucleus and reduces the loss of motor neurons after facial nerve transection in rats. However, high-dose EPO treatment has little effect on Bax expression.

The Erythropoietin Receptor: Dimerization and Intracellular Signal Transduction

Erythropoietin (EPO), a 34 kD glycopro-tein, is the principal growth factor regulating theproduction of circulating erythrocytes; EPO isessential for committed CFU - E erythroid pro-genitors to divide several times and then to dif-ferentiate into erythrocytes. Like most receptorsfor hematopoietic growth factors, the erythro-poietin receptor (EPO - R) is a type I trans-membrane protein and a member of the cytokinereceptor superfamily. These receptors containfour conserved cysteines and a Trp - Ser - X -

Protective effects of erythropoietin against acute lung injury in a rat model of acute necrotizing pancreatitis

AIM： TO investigate the effect of exogenous erythro- poietin （EPO） administration on acute lung injury （ALI） in an experimental model of sodium taurodeoxycholate- induced acute necrotizing pancreatitis （ANP）. METHODS： Forty-seven male Wistar albino rats were randomly divided into 7 groups： sham group （n = 5）, 3 ANP groups （n = 7 each） and 3 EPO groups （n = 7 each）. ANP was induced by retrograde infusion of 5% sodium taurodeoxycholate into the common bile duct. Rats in EPO groups received 1000 U/kg intramuscular EPO immediately after induction of ANP. Rats in ANP groups were given 1 mL normal saline instead. All animals were sacrificed at postoperative 24 h, 48 h and 72 h. Serum arnilase, IL-2, IL-6 and lung tissue malondialdehyde （MDA） were measured. Pleural effusion volume and lung/body weight （LW/BW） ratios were calculated. Tissue levels of TNF-a, IL-2 and IL-6 were screened immunohistochemically. Additionally, ox-LDL accumulation was assessed with immune-fluorescent staining. Histopathological alterations in the lungs were also scored.RESULTS： The mean pleural effusion volume, calculated LW/BW ratio, serum IL-6 and lung tissue MDA levels were significantly lower in EPO groups than in ANP groups. No statistically significant difference was observed in either serum or tissue values of IL-2 among the groups. The level of tumor necrosis factor-（~ （TNF-（~） and IL-6 and accumulation of ox-LDL were evident in the lung tissues of ANP groups when compared to EPO groups, particularly at 72 h. Histopathological evaluation confirmed the improvement in lung injury parameters a^er exogenous EPO administration, particularly at 48 h and 72 h. CONCLUSION： EPO administration leads to a significant decrease in ALI parameters by inhibiting polymorphonuclear leukocyte （PMNL） accumulation, decreasing the levels of proinflammatory cytokines in circulation, preserving microvascular endothelial cell integrity and reducing oxidative stress-associated lipid peroxidation and therefore, can be regarded as a cytoprotective agent in ANP-induced ALI.