Effect Of Recombinant Human Erythropoietin Research Articles

Cytoprotective Effect of Recombinant Human Erythropoietin Produced in Transgenic Tobacco Plants

Asialo-erythropoietin, a desialylated form of human erythropoietin (EPO) lacking hematopoietic activity, is receiving increased attention because of its broader protective effects in preclinical models of tissue injury. However, attempts to translate its protective effects into clinical practice is hampered by unavailability of suitable expression system and its costly and limit production from expensive mammalian cell-made EPO (rhuEPOM) by enzymatic desialylation. In the current study, we took advantage of a plant-based expression system lacking sialylating capacity but possessing an ability to synthesize complex N-glycans to produce cytoprotective recombinant human asialo-rhuEPO. Transgenic tobacco plants expressing asialo-rhuEPO were generated by stably co-expressing human EPO and β1,4-galactosyltransferase (GalT) genes under the control of double CaMV 35S and glyceraldehyde-3-phosphate gene (GapC) promoters, respectively. Plant-produced asialo-rhuEPO (asialo-rhuEPOP) was purified by immunoaffinity chromatography. Detailed N-glycan analysis using NSI-FTMS and MS/MS revealed that asialo-rhuEPOP bears paucimannosidic, high mannose-type and complex N-glycans. In vitro cytoprotection assays showed that the asialo-rhuEPOP (20 U/ml) provides 2-fold better cytoprotection (44%) to neuronal-like mouse neuroblastoma cells from staurosporine-induced cell death than rhuEPOM (21%). The cytoprotective effect of the asialo-rhuEPOP was found to be mediated by receptor-initiated phosphorylation of Janus kinase 2 (JAK2) and suppression of caspase 3 activation. Altogether, these findings demonstrate that plants are a suitable host for producing cytoprotective rhuEPO derivative. In addition, the general advantages of plant-based expression system can be exploited to address the cost and scalability issues related to its production.

Effects of recombinant human erythropoietin on the expression of glutamine synthetase of cultured retinal Miiller cells under high glucose condition

Objective To investigate the effect of recombinant human erythropoietin （rhEPO） on the expression of glutamine synthetase （GS） of cultured rat retinal Mtiller cells in high glucose environment in vitro. Methods Mtiller cells were isolated from retinas of 10 Sprague-Dawley rats at postnatal day three to five by trypsin digestion, and were randomly divided into six groups, including normal control group, high glucose group, high glucose ＋U/ml rhEPO group, high glucose＋10 U/ml rhEPO group, high glucose＋20 U/ml rhEPO group, high glucose＋ 40 U/ml rhEPO groups. After 48 hours, the apoptosis of retinal MUller cells were assayed by terminal transferase-mediated DNA end labelling assay, and the expression levels of GS protein were detected with semi-quantitative immunoeytochemistry. Results Compared with the normal control group, the cell viability and GS protein were reduced while the cell death increased in Mtiller cells cultured in high glucose, the difference was statistically significant （t= 27.4, P~0.01）. Compared with the high glucose group, rhEPO treatment reduced the apoptotic Mtiller cells （t= 857.2, 2 374.6, 2 473.2, 2 537.7; P〈0.01）, induced the expression of GS proteins （t=3.2, 18.0, 22.5, 26.4; P〈0.05）. Conclusions rhEPO can protect Muller cells from apoptosis under high glucose condition. The mechanism may be related to its function to up-regulate the GS protein expression, promote glutamic acid cycle, and reduce the excitotoxicity effects of high concentration of glutamate. Key words: Erythropoietin/pharmacology; Microglia; Glutamate-ammonia ligase

Erythropoietin reduces brain injury after intracerebral hemorrhagic stroke in rats

Erythropoietin (EPO) has been shown to be neuroprotective in various models of neuronal injury. The aim of the present study was to investigate the beneficial effect of recombinant human EPO (rhEPO) following intracerebral hemorrhage (ICH) and the underlying molecular and cellular mechanisms. ICH was induced using autologous blood injection in adult rats. rhEPO (5000 IU/kg) or vehicle was administered to rats with ICH 2 h following surgery and every 24 h for 1 or 3 days. To study the involvement of the PI3K signaling pathway in the rhEPO‑mediated effect, the PI3K inhibitor wortmannin (15 µg/kg), was intravenously administered to rats with ICH 90 min prior to rhEPO treatment. Brain edema was measured 3 days following ICH and behavioral outcomes were measured at 1, 7, 14, 21 and 28 days following ICH using the modified neurological severity score (mNSS) and the corner turn test. Proinflammatory cytokines, including tumor necrosis factor (TNF)‑α, interleukin (IL)-1β and IL-6, in the ipsilateral striatum were analyzed using an enzyme-linked immunosorbent assay 24 h following ICH. Neuronal apoptosis in the perihematomal area was determined by NeuN and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) double-staining. The results showed that rhEPO treatment reversed ICH, increased brain water content, upregulated proinflammatory cytokines, neuronal loss and apoptosis in the perihematomal area and rescued behavioral deficits in injured rats. Inhibiting the PI3K pathway with wortmannin abolished the rhEPO‑mediated neuroprotective effects. Moreover, western blot analysis showed that rhEPO induced the upregulation of Akt phosphorylation and downregulation of glycogen synthase kinase (GSK)‑3β phosphorylation, which were reversed by pretreatment with wortmannin, indicating the involvement of PI3K signaling in rhEPO-mediated anti-apoptotic and anti-inflammatory effects following ICH. In conclusion, these results suggested that rhEPO may exert its beneficial effects in ICH through the activation of the PI3K signaling pathway.

Impacts of Recombinant Human Erythropoietin Treatment During Predialysis Periods on the Progression of Chronic Kidney Disease in a Large‐Scale Cohort Study (Co‐JET study)

The effect of recombinant human erythropoietin (rHuEPO) treatment on the progression of chronic kidney disease (CKD) has not been fully evaluated in Japan. We therefore retrospectively evaluated this in a sub-cohort of a prospective multicenter study to investigate optimal hemoglobin (Hb) level of CKD patients on hemodialysis (HD) treated with rHuEPO; Japan Erythropoietin Treatment Study for Target Hb and Survival (JET study). Effect of rHuEPO treatment during predialysis period to delay initiation of HD was retrospectively assessed in 2434 patients from the JET study comparing groups with and without rHuEPO treatment. The assessment was done by Cox proportional hazards regression analysis and inverse probability-weighted (IPW) analysis to adjust for time-dependent confounders. The weights used in the IPW analysis were calculated using a logistic model that included baseline confounders and time-dependent variables. During the predialysis period, 71.7% (1746 patients) were treated with rHuEPO (mean Hb level of 8.7 g/dL at initiation of rHuEPO treatment). Covariates significantly associated with initiation of rHuEPO treatment were Hb level, serum creatinine level, age, diabetes, cardiac insufficiency, and hypertension. The adjusted hazard ratio for time until HD initiation under rHuEPO treatment was 0.272 (95% CI, 0.223-0.331; P < 0.001) in the Cox analysis and 0.63 (95% CI, 0.53-0.76; P < 0.0001) in the IPW analysis. This retrospective study suggests that rHuEPO treatment during the predialysis period has preventive effects on the progression of CKD although further prospective investigation on the efficacy is needed.

Human erythropoietin gene delivery for cardiac remodeling of myocardial infarction in rats

Considerable efforts have been made to exploit cardioprotective drugs and gene delivery systems for myocardial infarction (MI). The promising cardioprotective effects of recombinant human erythropoietin (rHuEPO) protein in animal experiments have not been consistently reproduced in clinical human trials of acute MI; however, the mechanisms underlying the inconsistent discrepancies are not yet fully understood. We hypothesized that the plasmid human erythropoietin gene (phEPO) delivered by our bioreducible polymer might produce cardioprotective effects on post-infarct cardiac remodeling. We demonstrated that intramyocardial delivery of phEPO by an arginine-grafted poly(disulfide amine) (ABP) polymer in infarcted rats preserves cardiac geometry and systolic function. The reduced infarct size of phEPO/ABP delivery was followed by decrease in fibrosis, protection from cardiomyocyte loss, and down-regulation of apoptotic activity. In addition, the increased angiogenesis and decreased myofibroblast density in the border zone of the infarct support the beneficial effects of phEPO/ABP administration. Furthermore, phEPO/ABP delivery induced prominent suppression on Ang II and TGF-β activity in all subdivisions of cardiac tissues except for the central zone of infarct. These results of phEPO gene therapy delivered by a bioreducible ABP polymer provide insight into the lack of phEPO gene therapy translation in the treatment of acute MI to human trials.

SAT0116 Safety and Efficacy of Ara290, a Non-Hematopoietic Erythropoietin Derived Peptide, in a 4 Weeks Phase II Open Label Trial in Patients with Active Rheumatoid Arthritis.

BackgroundErythropoietin, a well-known stimulator of erythrocyte production, also has nonhematopoietic activities, that can generally be summarized as counteracting the actions of proinflammatory cytokines. It has been suggested previously that erythropoietin...

Changes in Brain Tissue Oxygenation After Treatment of Diffuse Traumatic Brain Injury by Erythropoietin*

To investigate the effects of recombinant human erythropoietin on brain oxygenation in a model of diffuse traumatic brain injury. Adult male Wistar rats. Neurosciences and physiology laboratories. Thirty minutes after diffuse traumatic brain injury (impact-acceleration model), rats were intravenously administered with either a saline solution or a recombinant human erythropoietin (5000 IU/kg). A third group received no traumatic brain injury insult (sham-operated). Three series of experiments were conducted 2 hours after traumatic brain injury to investigate: 1) the effect of recombinant human erythropoietin on brain edema using diffusion-weighted magnetic resonance imaging and measurements of apparent diffusion coefficient (n = 11 rats per group); local brain oxygen saturation, mean transit time, and blood volume fraction were subsequently measured using a multiparametric magnetic resonance-based approach to estimate brain oxygenation and brain perfusion in the neocortex and caudoputamen; 2) the effect of recombinant human erythropoietin on brain tissue PO₂ in similar experiments (n = 5 rats per group); and 3) the cortical ultrastructural changes after treatment (n = 1 rat per group). Compared with the sham-operated group, traumatic brain injury saline rats showed a significant decrease in local brain oxygen saturation and in brain tissue PO₂ alongside brain edema formation and microvascular lumen collapse at H2. Treatment with recombinant human erythropoietin reversed all of these traumatic brain injury-induced changes. Brain perfusion (mean transit time and blood volume fraction) was comparable between the three groups of animals. Our findings indicate that brain hypoxia can be related to microcirculatory derangements and cell edema without evidence of brain ischemia. These changes were reversed with post-traumatic administration of recombinant human erythropoietin, thus offering new perspectives in the use of this drug in brain injury.

Recombinant human erythropoietin pretreatment alleviates renal glomerular injury induced by cardiopulmonary bypass by reducing transient receptor potential channel 6–nuclear factor of activated T-cells pathway activation

Acute renal injury after cardiopulmonary bypass is common and associated with high mortality. We aimed to demonstrate the glomerular protective effects of recombinant human erythropoietin using an in vivo rat cardiopulmonary bypass model and to explore the possible mechanism. Dose-related renal protective effects of recombinant human erythropoietin were studied in phase I. Male Sprague Dawley rats were randomly divided into 5 groups: sham group, cardiopulmonary bypass group, and 3 recombinant human erythropoietin-treated cardiopulmonary bypass groups (bolus doses of 500, 3000, and 5000 U/kg 24 hours before surgery). Blood and urine samples were collected just before surgery and at 2, 4, 24, 48, and 72 hours after surgery. In phase II, rats were divided into 3 groups: sham group, cardiopulmonary bypass group, and 5000 U/kg recombinant human erythropoietin group. Kidneys were harvested at 4, 24, 48, and 72 hours after surgery. Ultra-organization of glomeruli was observed. Glomerular transient receptor potential channel 6 (TRPC6) expression was studied by immunofluorescence and Western blot. Nuclei nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) activity was analyzed by enzyme-linked immunosorbent assays and electrophoretic mobility shift assay. Pretreatment of 5000 U/kg recombinant human erythropoietin decreased the urine protein (72 hours: 7.82 ± 1.13 g/L vs 11.28 ± 1.73 g/L), serum creatinine (72 hours: 35.0 ± 3.5 μmol/L vs 60.7 ± 7.6 μmol/L), and cystatin-C (2 hours: 336.5 ± 28.2 μg/L vs 452.6 ± 63.8 μg/L) compared with the control group (P < .01). Cardiopulmonary bypass induced morphologic abnormalities of podocyte foot processes and slit diaphragms, which was improved by recombinant human erythropoietin. Furthermore, recombinant human erythropoietin significantly relieved glomerular TRPC6 increase and NFATc1 activation induced by cardiopulmonary bypass. Pretreatment of 5000 U/kg recombinant human erythropoietin elicited potent glomerular protection against cardiopulmonary bypass. This protection may be partly due to downregulation of glomerular TRPC6-NFATc1 pathway.

Effects of Recombinant Human Erythropoietin on Resistance Artery Endothelial Function in Stage 4 Chronic Kidney Disease

BackgroundRecent studies have raised concern about the safety of erythropoiesis‐stimulating agents because of evidence of increased risk of hypertension and cardiovascular morbidity and mortality in chronic kidney disease (CKD) patients. In the present study, we investigated the effects of recombinant human erythropoietin (EPO) on endothelial function of gluteal subcutaneous resistance arteries isolated from 17 stage 4 patients (estimated glomerular filtration rate 21.9±7.4 mL/min per 1.73 m2) aged 63±13 years.Methods and ResultsArteries were mounted on a pressurized myograph. EPO impaired endothelium‐dependent relaxation in a concentration‐dependent manner. The maximal response to acetylcholine with EPO at 1, 10, and 20 IU/mL was reduced by 12%, 34%, and 43%, respectively, compared with the absence of EPO (P<0.001). EPO‐induced endothelial dysfunction was significantly associated with carotid stiffness and history of cardiovascular events. EPO had no effect on norepinephrine‐induced vasoconstriction or sodium nitroprusside–induced relaxation. ABT‐627, an endothelin type A receptor antagonist, and tempol, a superoxide dismutase mimetic, partially reversed the altered endothelial function in the presence of EPO (P<0.01). Increased expression of endothelin‐1 was found in the vessel wall after incubation with EPO.ConclusionsEPO alters endothelial function of resistance arteries in CKD patients via a mechanism involving in part oxidative stress and signaling through an endothelin type A receptor. EPO‐induced endothelial dysfunction could contribute to deleterious effects of EPO described in large interventional trials.

Protective effects of recombinant human erythropoietin on acute lung injury induced by sepsis in rats

Objective To investigate the protective effects of recombinant human erythropoietin (rHuEPO) on acute lung injury (ALI) induced by lipopolysaccharide (LPS).Methods Fourty-five rats were randomly (random number) assigned to three groups,namely control group,model group,and rHuEPO group.ALI was induced by intravenous injection of LPS (6 mg/kg).The rHuEPO (5000 U/kg) was injected intravenously into rats 60 min before LPS challenge.The general status of rats was observed.Twelve hours after modeling,the rats were sacrificed and the tissue samples including lung tissue and blood were collected.PaO2,PaCO2,pH,the lung wet/dry weight ratio,plasma cytokines [interleukin (IL) IL-6 and tumor necrosis factor-alpha (TNF-α)],and inducible nitric oxide synthase (iNOS) were detected.Cytokines were assayed with ELISA method.Pathological changes of lung tissues were observed under light microscope and transmission electron microscopy.Results (1) Compared with the control group,PaO2,pH in the model group and in the rHuEPO group were significantly lower (P ＜ 0.05),and PaCO2 were significantly higher (P ＜ 0.05).Compared with the model group,PaO2,pH in the rHuEPO group were significantly higher (P ＜ 0.05),and PaCO2 were significantly lower (P ＜ 0.05).(2) Compared with the control group,the W/D weight ratio of lung tissues in the model group and the rHuEPO group was significantly higher (P ＜ 0.05).Compared with the model group,the W/D weight ratio of lung tissues in the rHuEPO group significantly lower (P ＜ 0.05).(3) The levels of TNF-o,IL-6 and iNOS in serum of rats in the control group were lower than those in the model group and the rHuEPO group (P ＜0.01).The serum levels of TNF-α,IL-6 and iNOS of rats in the rHuEPO group were significantly lower compared with the model group (P ＜ 0.01).(4) The light microscopy and the transmission electron microscopy showed the model group had histopathologic changes with acute diffuse lung injury manifested by intra-alveolar hemorrhage,exudate,inflammatory cells infiltration,Ⅰ type and Ⅱ type epithelial cell necrosis and detachment,and the pathological changes of lung tissue in the rHuEPO group were not as serious as those in the LPS group,showing only a little inflammatory cells infiltration of focal alveoli.Conclusions Recombinant human erythropoietin can inhibit the genesis of TNF-α,IL-6 and iNOS in serum,modifying the inflammatory response and providing protective effects against acute lung injury induced by sepsis. Key words: Recombinant human erythropoietin ; Lipopolysaccharides ; Sepsis ; Acute lung injury

Recombinant human erythropoietin preconditioning attenuates liver ischemia reperfusion injury through the phosphatidylinositol-3 kinase/AKT/endothelial nitric oxide synthase pathway

BackgroundThe exact mechanism by which erythropoietin protects the liver from ischemia reperfusion (I/R) injury is not yet known. In the present study, we examined the role of protein kinase B (PKB/AKT) and endothelial nitric oxide synthase (eNOS) in the protective effect of recombinant human erythropoietin (rHuEPO) on I/R injury of the liver. Materials and methodsWe used a liver in situ I/R model. One hundred twenty adult male Sprague-Dawley rats were divided randomly into six groups. rHuEPO and (or) LY294002 were injected in the tail vein before the operation, and its effect was assessed by measuring the serum levels of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, nitric oxide (NO), and endothelin-1 (ET-1) and by histologic analysis. The expression of erythropoietin receptor (EPOR) and eNOS was measured by real-time polymerase chain reaction. Total AKT and eNOS and phosphorylated AKT and eNOS were examined by western blot. ResultsrHuEPO dramatically attenuated the functional and morphologic injuries. The serum levels of alanine aminotransferase and lactate dehydrogenase were significantly decreased, but the amount of NO in the serum was increased in the I/R + rHuEPO group. Accordingly, rHuEPO administration significantly ameliorated the histologic damages at 6 h after reperfusion. rHuEPO significantly stimulated the phosphorylation of AKT and eNOS in the rats after liver I/R. ConclusionsThe protective effect of rHuEPO in I/R injury is mediated via the activation of the phosphatidylinositol-3 kinase/AKT/eNOS signaling pathway, at least in part, by increasing p-AKT and p-eNOS and leads to the maintenance of an elevated level of NO.

Dual Inhibiting Senescence and Epithelial-to-Mesenchymal Transition by Erythropoietin Preserve Tubular Epithelial Cell Regeneration and Ameliorate Renal Fibrosis in Unilateral Ureteral Obstruction

This study aims to investigate the renoprotective effect of recombinant human erythropoietin (rhEPO) treatment could preserve tubular epithelial cell regeneration and ameliorate renal fibrosis by dual inhibition of stress-induced senescence and EMT in unilateral ureteric obstruction (UUO) mouse model. UUO or sham-operated mice were randomly assigned to receive rhEPO or vehicle treatment and were sacrificed on days 3, 7, and 14. Kidney specimens were fixed for histopathological and immunohistochemical study. The expression of S100A4, TGF-β1, BMP-7, Smad2/3, Smad1/5/8, and p16INK4a was determined by western blot and real-time RT-PCR. Vehicle treated UUO mice had increased tubular atrophy and interstitial fibrosis within 3 to 14 days. An increase in TGF-β1, Smad2/3, S100A4, and p16INK4a expression and a decrease in BMP-7 and Smad1/5/8 expression were observed in the obstructed kidneys. p16INK4a was positively correlated with TGF-β1/Smad2/3 and negatively correlated with BMP-7/Smad1/5/8 in UUO mice. rhEPO treatment significantly suppressed the upregulation of TGF-β, Smad2/3, S100A4, and p16INK4a and preserved the downregulation of BMP-7 and Smad1/5/8, resulting in markedly reduced TA/IF compared to the vehicle treated mice. The renoprotective effects of rhEPO could ameliorate renal TA/IF by modulating senescence and EMT which could be a part of therapeutic option in patients with chronic kidney disease.

The protective effect of recombinant human erythropoietin against cisplatin-induced renal and hepatic dysfunctions in Wistar rats

Cisplatin (Cisp) is one of the most effective chemotherapeutic drugs. However, the dose of Cisp is greatly limited by its toxicity. Recombinant human erythropoietin (rhEPO), a hormone that regulates hematopoiesis, has also been shown to exert tissue-protective effects. The purpose of this study was to explore the protective effect of rhEPO against Cisp-induced renal and liver dysfunctions. Adult male Wistar rats were divided into six groups of six each: control, rhEPO-alone group, Cisp-alone group and rhEPO + Cisp group (pretreatment, cotreatment and posttreatment conditions). Our results showed that Cisp-induced a marked renal and liver failure characterized by a significant decrease in body weight, organ weight and organ ratio and a significant increase in creatinine, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, G-glutamyl transferase, alkaline phosphatase, bilirubin conjugated and bilirubin total levels in serum. Histological examination showed that Cisp caused kidney alterations. rhEPO treatments restored body weight, organ weight and organ ratio as well as serum biochemical parameters changed due to Cisp exposure.

Effect of Recombinant Erythropoietin on Functional Activity of Cultured Human Cells

We studied the effect of recombinant human erythropoietin on functional activity of skin cells in vitro. It was found that erythropoietin stimulated proliferation of mesenchymal and epithelial cells and effectively protected epidermal HaCaT cells from apoptosis. Insignificant effect of erythropoietin on contraction of collagen gel by mesenchymal cells was revealed. These findings suggest that erythropoietin can be a promising component of wound-healing preparations.

Induction of DNA fragmentation, chromosome aberrations and micronuclei by cisplatin in rat bone-marrow cells: Protective effect of recombinant human erythropoietin

Cisplatin (Cisp) is one of the most effective chemotherapeutic agents. However, at higher doses several side effects may occur. Recombinant human erythropoietin (rhEPO), a glycoprotein regulating haematopoiesis, has recently been shown to exert an important cyto-protective effects in many tissues. The purpose of this study was to explore whether rhEPO protects against Cisp-induced genotoxicity in rat bone-marrow cells. Adult male Wistar rats were divided into six groups of 18 animals each: control group, rhEPO-alone group, Cisp-alone group and three rhEPO+Cisp-groups (pre-, co- and post-treatment condition, respectively). Our results show that Cisp induced a noticeable genotoxic effect in rat bone-marrow cells. In all types of treatment, rhEPO significantly decreased the frequency of micronuclei, the percentage of chromosome aberrations and the level of DNA damage. The protective effect of rhEPO was more efficient when it was administrated 24h before exposure to Cisp.

Three weeks of erythropoietin treatment hampers skeletal muscle mitochondrial biogenesis in rats

The blood O(2)-carrying capacity is maintained by the O(2)-regulated production of erythropoietin (Epo), which stimulates the proliferation and survival of red blood cell progenitors. Epo has been thought to act exclusively on erythroid progenitor cells. However, recent studies have identified the erythropoietin receptor (EpoR) in other cells, such as neurons, astrocytes, microglia, heart, cancer cell lines, and skeletal muscle provides evidence for a potential role of Epo in other tissues. In this study we aimed to determine the effect of recombinant human erythropoietin (rHuEpo) on skeletal muscle adaptations such as mitochondrial biogenesis, myogenesis, and angiogenesis in different muscle fibre types. Fourteen male Wistar rats were randomly divided into two experimental groups, and saline or rHuEpo (300 IU) was administered subcutaneously three times a week for 3 weeks. We evaluated the protein expression of intermediates involved in the mitochondrial biogenesis cascade, the myogenic cascade, and in angiogenesis in the oxidative soleus muscle and in the glycolytic gastrocnemius muscle. Contrary to our expectations, rHuEpo significantly hampered the mitochondrial biogenesis pathway in gastrocnemius muscle (PGC-1α, mTFA and cytochrome c). We did not find any effect of the treatment on cellular signals of myogenesis (MyoD and Myf5) or angiogenesis (VEGF) in either soleus or gastrocnemius muscles. Finally, we found no significant effect on the maximal aerobic velocity at the end of the experiment in the rHuEpo-treated animals. Our findings suggest that 3 weeks of rHuEpo treatment, which generates an increase of oxygen carrying capacity, can affect mitochondrial biogenesis in a muscle fibre-specific dependent manner.

Changes of growth associated protein and effect of recombinant human erythropoietin in rats after traumatic optic neuropathy

Objective To study changes of growth associated protein(GAP-43) and effect of recombinant human erythropoietin (rhEPO) in rats after optic nerves crushed.Method The animal model of traumatic optic neuropathy was established,Sixty-three healthy aduh SD rats without eye diseases were divided into three groups randomly:control group,crush group and rhEPO group.The morphology of retina and optic nerve was observed.Changes of GAP-43 in optic nerve were studied with immunohistochemistry staining at 1 d,4 d,7 d,14 d and 28 d after crush.Results The pathological change of retina and optic nerve in rhEPO group reduced than in crush group.Immunohistochemistry results showed that there were no significant difference of GAP-43 expression between crush group and rhEPO group ( P ＞ 0.05 ) at 4 d,7 d after crush.However,the cxpression of GAP-43 in rhEFO group signmcatily increased than that of crush group at 14 d and 28 d after crush.(P＜0.05).Conclusion RhEPO may be helpful in repairing and regenerating of the retina ganglion cells and optic nerve after crush. Key words: Optic nerve injury; Growth associated protein - 43 ; Erythropoietin; Retinal ganglion cell

Reduced EPO receptor expression may contribute to limited pleiotropic effects of EPO during critical illness

We showed neuroprotective and renoprotective effects of recombinant human erythropoietin (rhEPO) after kidney and spinal cord ischemia/reperfusion (I/R) injury [1,2], but clinical studies using rhEPO to prevent acute kidney injury yielded equivocal results [3,4]. Increased cytokine release and/or oxidative stress can cause EPO resistance due to receptor modification and/or downregulation [5]. Since we recently failed to confirm rhEPO-related kidney protection in atherosclerotic swine [6], we compared kidney EPO receptor expression in swine strains with and without pre-existing vascular disease and kidney dysfunction.

The Journal of Physiology Annual Report 2011–12

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Contrasting effect of recombinant human erythropoietin on breast cancer cell response to cisplatin induced cytotoxicity

BackgroundHuman recombinant erythropoietin (rHuEpo) that is used for the treatment of the chemotherapy-induced anaemia in cancer patients was shown to cause detrimental effects on the course of disease due to increased adverse events inflicting patient’s survival, potentially related to rHuEpo-induced cancer progression. In this study, we elucidate the effect of rHuEpo administration on breast cancer cell proliferation and gene expression after cisplatin (cDDP) induced cytotoxicity.Materials and methodsTwo breast carcinoma models, MCF-7 and MDA-MB-231 cell lines, were used differing in oestrogen (ER) and progesterone (PR) receptors and p53 status. Cells were cultured with or without rHuEpo for 24 h or 9 weeks and their growth characteristics after cDDP treatment were assessed together with expression of genes involved in the p53-signaling pathway.ResultsShort-term exposure of breast cancer cells to rHuEpo lowers their proliferation and reduces cDDP cytotoxic potency. In contrast, long-term exposure of MCF-7 cells to rHuEpo increases proliferation and predisposes MCF-7 cells to cDDP cytotoxicity, but has no effect on MDA-MB-231 cells. MDA-MB-231 cells show altered level of ERK phosphorylation, indicating involvement of MAPK signalling pathway. Gene expression analysis of p53-dependent genes and bcl-2 gene family members confirmed differences between long and short-term rHuEpo effects, indicating the most prominent changes in BCL2 and BAD expression.ConclusionsProliferation and survival characteristics of MCF-7 cells are reversely modulated by the length of the rHuEpo exposure. On the other hand, MDA-MB-231 cells are almost irresponsive to long-term rHuEpo, supposedly due to the mutated p53 and ER(+)/PR(−) status. The p53 and ER/PR status may predict tumour response on rHuEpo and cDDP treatment.