Anemia, complicating the course of chronic kidney disease, is a significant parameter, whether interpreted as subjective impairment or an objective prognostic marker. Renal anemia is predominantly due to relative erythropoietin (EPO) deficiency. EPO inhibits apoptosis of erythrocyte precursors. Studies using EPO substitution have shown that increasing hemoglobin (Hb) levels up to 10–11 g/dL is associated with clinical improvement. However, it has not been unequivocally proven that further intensification of erythropoiesis stimulating agent (ESA) therapy actually leads to a comprehensive benefit for the patient, especially as ESAs are potentially associated with increased cerebro-cardiovascular events. Recently, new developments offer interesting options not only via stimulating erythropoeisis but also by employing additional mechanisms. The inhibition of activin, a member of the transforming growth factor superfamily, has the potential to correct anemia by stimulating liberation of mature erythrocyte forms and also to mitigate disturbed mineral and bone metabolism as well. Hypoxia-inducible factor prolyl hydroxylase inhibitors also show pleiotropic effects, which are at the focus of present research and have the potential of reducing mortality. However, conventional ESAs offer an extensive body of safety evidence, against which the newer substances should be measured. Carbamylated EPO is devoid of Hb augmenting effects whilst exerting promising tissue protective properties. Additionally, the role of hepcidin antagonists is discussed. An innovative new hemodialysis blood tube system, reducing blood contact with air, conveys a totally different and innocuous option to improve renal anemia by reducing mechanical hemolysis.
Activins ; Anemia* ; Apoptosis ; Erythrocytes ; Erythropoiesis* ; Erythropoietin ; Hematinics* ; Hemolysis ; Hepcidins ; Humans ; Metabolism ; Miners ; Mortality ; Prolyl-Hydroxylase Inhibitors ; Renal Dialysis ; Renal Insufficiency, Chronic ; Transforming Growth Factors

BACKGROUNDRecombinant human-erythropoietin (rh-EPO) has therapeutic efficacy for premature infants with brain damage during the active rehabilitation and anti-inflammation. In the present study, we found that the rh-EPO was related to the promotion of neovascularization. Our aim was to investigate whether rh-EPO augments neovascularization in the neonatal rat model of premature brain damage through the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) signaling pathway.

METHODSPostnatal day 5 (PD5), rats underwent permanent ligation of the right common carotid artery and were exposed to hypoxia for 2 h. All the rat pups were randomized into five groups as follows: (1) control group; (2) hypoxia-ischemic (HI) group; (3) HI + LY294002 group; (4) HI + rh-EPO group; and (5) HI + rh-EPO + LY294002 group. The phospho-Akt protein was tested 90 min after the whole operation, and CD34, vascular endothelial growth factor receptor 2 (VEGFR2), and vascular endothelial growth factor (VEGF) were also tested 2 days after the whole operation.

RESULTSIn the hypoxic and ischemic zone of the premature rat brain, the rh-EPO induced CD34+ cells to immigrate to the HI brain zone (P < 0.05) and also upregulated the VEGFR2 protein expression (P < 0.05) and VEGF mRNA level (P < 0.05) through the PI3K/Akt (P < 0.05) signaling pathway when compared with other groups.

CONCLUSIONSThe rh-EPO treatment augments neovascularization responses in the neonatal rat model of premature brain damage through the PI3K/Akt signaling pathway. Besides, the endogenous EPO may exist in the HI zone of rat brain and also has neovascularization function through the PI3K/Akt signaling pathway.

Animals ; Animals, Newborn ; Antigens, CD34 ; metabolism ; Brain ; drug effects ; metabolism ; pathology ; Disease Models, Animal ; Erythropoietin ; genetics ; metabolism ; therapeutic use ; Female ; Humans ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; Neovascularization, Physiologic ; drug effects ; Phosphatidylinositol 3-Kinase ; metabolism ; Pregnancy ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; genetics ; metabolism ; therapeutic use ; Signal Transduction ; drug effects ; Vascular Endothelial Growth Factor A ; genetics ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism

OBJECTIVETo explore the influence of GATA-1 on expression of EpoR in bone marrow CD71+ cells of rat model with high altitude polycythemia (HAPC).

METHODSForty-eight male SD rats were randomly divided into normal control and HAPC model group. HAPC model was established at the altitude of 4 300 meters in the natural environment, and verified by bone marrow cell counts and hematological parameters. Myeloid CD71+ cells were separated by the density gradient centrifugation combined with magnetic activated cell sorting. The expression of EpoR on cell membrane was detected by flow cytometry and cell immunofluorescence. The expression changes of GATA-1 and EpoR mRNA and protein were detected by Q-PCR and Western blot, respectively. CD71+ cells were cultured under normoxia and hypoxia, respectively. After transfection for 96 h, the optimal interference sequence GATA-1 shRNA1 was selected. And the mRNA and protein expression level of GATA-1 and EpoR were detected by Q-PCR and Western blot respectively.

RESULTSThe animal model with HAPC was established successfully and comfirmed by the bone marrow cell counting and the hematologic parameters in comparison with that of the normal control. EpoR expression on the myeloid CD71+ cell membrane in HAPC group was significantly higher than that in normal control (P<0.05). The expression of GATA-1 and EpoR in myeloid CD71+ cells of HAPC group was higher than that in control group (P<0.05). The mRNA and protein expression of GATA-1 and EpoR in two groups positively correlated (control group, r=0.929, P<0.01, r=0.802, P<0.05; HAPC group, r=0.822, P<0.05, r=0.839, P<0.01). However, the mRNA and protein expression of EpoR at normoxia and hypoxia was significantly lower than that in negative control group after interfernce with GATA-1 shRNA1 for 96 h (P<0.05). And the expression of GATA-1 and EpoR under hypoxia was higher than that in normoxia.

CONCLUSIONThe effect of GATA-1 on EpoR expression may be correlated with the pathogenesis of HAPC.

Altitude ; Animals ; Antigens, CD ; metabolism ; Bone Marrow Cells ; metabolism ; Cell Separation ; Disease Models, Animal ; Flow Cytometry ; GATA1 Transcription Factor ; metabolism ; Male ; Polycythemia ; metabolism ; RNA, Messenger ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptors, Erythropoietin ; metabolism ; Receptors, Transferrin ; metabolism

OBJECTIVETo explore the impacts of erythropoietin on vascular endothelial growth factor receptor 2 (VEGFR2) by the extracellular signal-regulated kinase (ERK) signaling pathway in a neonatal rat model of periventricular white matter damage.

METHODSAll of postnatal day 4 rats were randomized into three groups: the sham group [without hypoxia-ischemia (HI)], the HI group (HI with saline administration), and the erythropoietin (EPO) group [HI with recombinant human erythropoietin (rh-EPO) administration]. Rat pups underwent permanent ligation of the right common carotid artery, followed by 6% O2 for 2 hours or sham operation and normoxic exposure. Immediately after the HI, rats received a single intraventricular injection of rh-EPO (0.6 IU/g body mass) or saline. ERK and phosphorylation-ERK were examined at 60 minutes and 90 minutes after operation, and VEGFR2 were detected at 2 and 4 days after operation by using Western blot.

RESULTSAt 60 minutes and 90 minutes after operation, the proteins of phosphorylation-ERK were significantly higher in HI rats than in the sham rats and significantly higher in HI+EPO rats than in the HI rats (P<0.05). Two days after operation, VEGFR2 was not significantly different between sham and HI rats. However, the proteins of VEGFR2 were increased after administration of rh-EPO (P<0.05). Four days after operation, the proteins of VEGFR2 were significantly higher in HI rats than in the sham rats and significantly higher in HI+EPO rats than in the HI rats (P<0.05).

CONCLUSIONEPO may regulate VEGFR2 expression by affecting the intracranial ERK signaling pathways.

Animals ; Animals, Newborn ; Disease Models, Animal ; Erythropoietin ; pharmacology ; Humans ; Hypoxia-Ischemia, Brain ; physiopathology ; MAP Kinase Signaling System ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; pharmacology ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism ; White Matter ; physiopathology

OBJECTIVETo explore the effect of recombinant human erythropoietin (rhEPO) on expression of brain-derived neurotrophic factor (BDNF) in different brain regions of aging rats.

METHODSForty male SD rats were randomized equally into negative control group, D-galactose group, EPO treatment group, and positive control group. Rat models of subacute aging were established by continuous subcutaneous injection of 5% D-galactose. Immunohistochemical staining was used to analyze the variation of BDNF expressions in different brain regions of the aging rats with different treatments.

RESULTSSignificant brain region-specific differences in BDNF expression were found among the rats in different groups. Compared with those in the negative control group, the numbers of BDNF-positive cells in the hippocampal CA1 region, CA3 region, dentate gyrus (DG) and frontal cortex were all decreased obviously in D-galactose group (P<0.05) but increased in both EPO group and the positive control group (P<0.05) without significant differences between the latter two groups. In the rats in the same group, the number of BDNF-positive cells varied markedly in different brain regions (P<0.05), and the expression level of BDNF was the highest in the frontal cortex followed by the hippocampal CA3 region and the dentate gyrus, and was the lowest in the hippocampal CA1 region.

CONCLUSIONTreatment with rhEPO enhances the expression of BDNF in rat neural cells, suggesting that rhEPO may protect the nervous system from aging by regulating the BDNF pathway.

Aging ; Animals ; Brain-Derived Neurotrophic Factor ; metabolism ; CA1 Region, Hippocampal ; metabolism ; CA3 Region, Hippocampal ; metabolism ; Dentate Gyrus ; metabolism ; Erythropoietin ; pharmacology ; Frontal Lobe ; metabolism ; Galactose ; Humans ; Male ; Neurons ; drug effects ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; pharmacology

OBJECTIVE: To explore the relationship between injury age and expressions of erythropoietin (EPO) and its receptor EPOR in the brain tissue of rats after cerebral injury. METHODS: Seventy-two rats were randomly divided into control group (36 rats) and cerebral injury group (36 rats). The rats were sacrificed at 1, 2, 4, 8, 12, 24 h after cerebral injury (6 rats at each time point) and the brain tissues were extracted. The expressions of mRNA and protein of EPO and EPOR at different time points were detected by real-time fluorescent quantitative PCR and Western bloting. RESULTS: The expressions of EPO and EPOR increased within 24 h after injury. The expressions of mRNA and protein of EPO were related to the injury age, and the correlations were 0.875, 0.911, respectively (P < 0.05). The expressions of mRNA and protein of EPOR were related to the injury age, and the correlation coefficients were 0.936, 0.905, respectively (P < 0.05). CONCLUSION The expressions of EPO and EPOR increase gradually in the early stage of the rat's cerebral injury, which are associated with the injury age and could be a useful value for estimating injury age.
Animals ; Brain/metabolism* ; Brain Injuries/pathology* ; Erythropoietin/metabolism* ; RNA, Messenger/metabolism* ; Random Allocation ; Rats ; Receptors, Erythropoietin/metabolism* ; Time Factors

Amounts of researches show that EPO is characterized with neurotrophic and neuroprotective manner, especially in brain stroke, which attracts a large numbers of researchers to study it. With the accumulating researches on its neuroprotection, many related mechanisms were revealed, such as antioxidant, anti-apoptosis, angiogenesis, anti-inflammatory, which suggests a multiple targets role of EPO on brain stroke. However, because of the high risk of thromboembolism in clinical administration of rhEPO and its analogs, the herbs are potential to be a replacer for its less side effects. Many researchers suggested that a larger of herbs were founded having the action of increasing the endogenous EPO in the model of anemia and cerebral ischemia. At the same time, there herbs were also proved that they had the action of against cerebral ischemia while some without considering the role of EPO in the reports. Considering of the action of promoting EPO of these herbs and the neural protection of EPO, this essay mainly summarizes the studies of herbs promoting EPO in the cerebral ischemia and discusses the mechanism of regulating the EPO of these herbs, for the aim of finding the potential drugs against cerebral ischemia.
Animals ; Brain Ischemia ; drug therapy ; genetics ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Erythropoietin ; genetics ; metabolism ; Humans ; Neuroprotection ; drug effects ; Plants, Medicinal ; chemistry

PURPOSE: The purpose of this study was to evaluate whether any stage of diabetic retinopathy (DR) is associated with levels of plasma erythropoietin and other plasma parameters. METHODS: It was examined a representative sample of 180 type 2 diabetes patients aged 40 to 79 years. Ophthalmic examination including a funduscopic examination, performed by an experienced ophthalmologist and the retinal finding were classified according to the grading system for diabetic retinopathy of ETDRS (Early Treatment Diabetic Retinopathy Study). It was measured the levels of plasma erythropoietin, cholesterol, triglyceride, apolipoproteins A and B, C-reactive protein, fasting blood glucose and hemoglobin A1C (HbA1C) in 88 DR patients and 92 controls without DR. Risk factors correlated with DR were compared between groups. RESULTS: The study group of 180 patients included 72 males and 108 females. The mean age of the patients with and without DR was 57.36 ± 8.87 years and 55.33 ± 8.28 years, respectively. Of the 88 patients with DR, only 9 (10%) had proliferative DR and the rest suffered from non-proliferative DR. The mean plasma levels of erythropoietin in proliferative DR group showed a significant difference in comparison to other groups. The mean plasma levels of cholesterol, triglyceride, apolipoproteins A and B, C-reactive protein, and fasting blood glucose were not significantly different in the three groups except for HbA1C. The absolute relative risk (ARR) also showed that erythropoietin was an increasing risk for proliferative DR (ARR, 1.17; 95% confidence interval, 1.060 to 1.420; odds ratio,1.060). CONCLUSIONS: Of the factors studied, erythropoietin level showed significant increase in proliferative DR group. The stepwise raised in mean plasma erythropoietin level which demonstrates significant correlation with proliferative DR versus remaining two groups, will be an indication of its role in proliferative DR.
Adult ; Aged ; Blood Glucose/metabolism ; Cholesterol/blood ; Cross-Sectional Studies ; Diabetes Mellitus, Type 2/complications ; Diabetic Retinopathy/*blood/diagnosis/*epidemiology ; Enzyme-Linked Immunosorbent Assay ; Erythropoietin/*blood ; Female ; Fluorescein Angiography ; Hemoglobin A, Glycosylated/metabolism ; Humans ; Male ; Middle Aged ; Risk Factors

BACKGROUNDErythropoietin (EPO) and granulocyte colony-stimulating factor (G-CSF) are both potential novel therapeutics for use after myocardial infarction (MI). However, their underlying mechanisms remain unclear and the efficacy of monotherapy with EPO or G-CSF is also controversial. Therefore, we investigated the effects of combined treatment with EPO and G-CSF on neovascularization and cardiac function in post-infarction rats and explored the potential mechanisms.

METHODSFour groups of rats were used: control (saline injection after MI, i.h.), EPO (a single dose of 5 000 IU/kg after MI, i.h.), G-CSF (a dose of 50 µg× kg(-1)× d(-1) for 5 days after MI, i.h.), and both EPO and G-CSF (EPO+G-CSF, using the same regiment as above). Cardiac function was assessed by echocardiography before and 1 day, 7 days, 14 days and 21 days after MI. CD34(+)/Flk-1(+) cells in the peripheral blood were evaluated by flow cytometry before and 3 days, 5 days and 7 days after MI. The infarct area and angiogenesis in the peri-infarct area were analyzed. The mRNA and protein expression of vascular endothelial growth factor (VEGF) and stromal-derived factor-1a (SDF-1α) in the peri-infarct area were detected by real-time quantitative RT-PCR and Western blotting.

RESULTSCompared with the control and monotherapy groups, the EPO+G-CSF group had significantly increased CD34(+)/Flk-1(+) endothelial progenitor cells (EPCs) in the peripheral blood (P < 0.05), up-regulated VEGF and SDF-1α levels in the peri-infarct region (P < 0.05), enhanced capillary density (P < 0.05), reduced infarct size (P < 0.05) and improved cardiac structure and function (P < 0.05). G-CSF alone did not dramatically increase EPCs in the peripheral blood, enhance capillary density in the peri-infarct area or reduce infarct size compared with the control group.

CONCLUSIONSCombined treatment with EPO and G-CSF increased EPCs mobilization, up-regulated VEGF and SDF-1α levels in the post-infarction microenvironment, subsequently enhanced neovascularization in the peri-infarct region and reduced infarct size. All factors contributed to its beneficial effects on cardiac function in post-infarction rats.

Animals ; Blotting, Western ; Chemokine CXCL12 ; metabolism ; Echocardiography ; Erythropoietin ; therapeutic use ; Flow Cytometry ; Granulocyte Colony-Stimulating Factor ; therapeutic use ; Male ; Myocardial Infarction ; drug therapy ; metabolism ; Neovascularization, Physiologic ; drug effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effects of erythropoietin (EPO) on the neuronal proliferation and apoptosis in neonatal rats after infection-induced brain injury and the neuroprotective mechanism of EPO in neonatal rats with infection-induced brain injury.

METHODSTwenty-six two-day-old neonatal rats were randomly divided into 3 groups: control group (intraperitoneally given an equal volume of normal saline), lipopolysaccharide (LPS) group (intraperitoneally given LPS 0.6 mg/kg), and EPO group (intraperitoneally given LPS 0.6 mg/kg and EPO 5 000 U/kg). These groups were injected with respective drugs for 5 consecutive days. Meanwhile, each group was intraperitoneally injected with 5-bromo-2'-deoxyuridine (BrdU) (50 mg/kg) once a day for 5 consecutive days. The expression of BrdU and cleaved Caspase-3 in the hippocampal dentate gyrus was detected by immunohistochemistry at 24 hours after the last injection.

RESULTSThe number of neuronal cells in the hippocampal dentate gyrus in the LPS and EPO groups was significantly greater than in the control group (P<0.05), but there was no significant difference between the LPS and EPO groups. The EPO group had a significantly higher number of BrdU-positive cells in the subgranular zone of hippocampal dentate gyrus than the LPS group (51±9 vs 29±6; P<0.05), but a significantly lower number of BrdU-positive cells than the control group (51±9 vs 67±12; P<0.05). The EPO group had a significantly lower number of cleaved Caspase-3-positive cells in the subgranular zone of hippocampal dentate gyrus than the LPS group (27.9±1.5 vs 34.0±1.3; P<0.05), but a significantly higher number of cleaved Caspase-3-positive cells than the control group (27.9±1.5 vs 21.0±1.7; P<0.05).

CONCLUSIONSEPO can promote hippocampal neuronal proliferation and reduce neuronal apoptosis in neonatal rats after infection-induced brain injury.

Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Brain Diseases ; drug therapy ; pathology ; Bromodeoxyuridine ; metabolism ; Caspase 3 ; metabolism ; Cell Proliferation ; drug effects ; Erythropoietin ; pharmacology ; therapeutic use ; Hippocampus ; pathology ; Neurons ; pathology ; Rats ; Rats, Sprague-Dawley