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

This study was aimed to explore the expression of erythropoietin receptor (EPOR) on acute leukemia cells and its clinical significance. Bone marrow of 40 patients with acute leukemia (AL) and 24 patients with normal bone marrow as control group were collected. Samples came from outpatients and inpatients in our hospital. EPOR mRNA was detected by reverse transcription-PCR. The results showed that there was EPOR expression on AL cells, the expression rate was 57.5%, and the average expression level (Gray value) was 0.3549 ± 0.2800, but both were lower than that in control group (p < 0.05). There was no significant statistic difference of expression rate between acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) (p > 0.05), and expression level of AML EPOR was higher than that of ALL (p < 0.05). It is concluded that there is EPOR expression on AL cells, while the expression rate and expression level are lower than those in control group (p < 0.05). There is no significant statistic difference of the expression rate between AML and ALL (p > 0.05), and the expression level of AML EPOR is higher than that of ALL (p < 0.05).
Case-Control Studies ; Humans ; Leukemia, Myeloid, Acute ; genetics ; metabolism ; RNA, Messenger ; genetics ; Receptors, Erythropoietin ; genetics ; metabolism

Erythropoietin (EPO) is an acidic glycoprotein that was first detected as a hematopoietic factor and its synthesis is triggered in response to cellular hypoxia-sensing. EPO binds to type I cytokine receptors, which associate with the non-receptor tyrosine kinase Jak2, and thereby activate Stat 5a/5b, Ras/MAPK, and PI3-K/Akt signaling pathways. The recent discovery shows that there is a specific EPO/EPO-receptor system in the central nervous system (CNS), independently of the haematopoietic system. Hypoxia and anemia can up-regulate EPO/EPOR expressions in the CNS. Further studies demonstrate that EPO has substantial neuro-protective effects and acts as a neurotrophic factor on central cholinergic neurons, influencing their differentiation and regeneration. EPO also exerts neuro-protective activities in different models of brain damage in vivo and in vitro, such as hypoxia, cerebral ischaemia and sub-arachnoid haemorrhage. EPO may also be involved in synaptic plasticity via the inhibition or stimulation of various neurotransmitters. Therefore, human recombinant EPO that activate its receptors in the central nervous system might be utilized in the future clinical practice involving neuroprotection and brain repair.
Animals ; Brain ; metabolism ; Cell Differentiation ; drug effects ; Erythropoietin ; metabolism ; pharmacology ; Humans ; Neurons ; cytology ; drug effects ; Neuroprotective Agents ; metabolism ; pharmacology ; Receptors, Erythropoietin ; metabolism

OBJECTIVEFunctionally, erythropoietin (EPO) can promote the proliferation and growth of erythroid progenitor cells, and it is widely used in the treatment of anemia in chronic diseases caused by tumor and inflammation. However, it is unclear whether EPO has any effect on tumor cell iron metabolism and tumor cell proliferation. The purpose of this study was to explore the effects of recombinant human EPO (rhEPO) on the expression of transferrin receptor (TfR, CD(71) antigen) of leukemic cell K562 and its relation to cell cycle.

METHODSIn vitro culture of K562 cell was performed with additions of various concentrations of rhEPO and Fe. Treatments were terminated at 24 h and 72 h, respectively. Then each group of cells was incubated with FITC-IgG antibody to CD(71) or PI, a kind of DNA dye. And TfR expression and DNA synthesis status were analyzed by flow-cytometry.

RESULTS(1) The expression of TfR by K562 cells increased significantly when incubated for 72 h with different concentrations of rhEPO. The measurement values of 5 U/ml, 10 U/ml and 20 U/ml groups were 12.2 +/- 1.40, 10.7 +/- 0.99 and 11.1 +/- 0.90, respectively. They were markedly increased when compared with that of control group (6.27 +/- 0.11, P < 0.05). (2) When incubated with rhEPO (5 u/ml) alone or combined with FeCl(3) (100 micro mol/L), the percentages of cells in S phase were 51.1% and 59.6%, respectively. They significantly increased when compared with that of control group (42.9%, P < 0.05).

CONCLUSIONSIron is very important for the proliferation of both normal cells and leukemic cells. It is essential to the activity of ribonucleotide reductase (RR). The authors hypothesized that rhEPO would increase the expression of TfR and intracellular iron content of leukemic cells, which would enhance the DNA synthesis and cell proliferation. Therefore, the clinical application of rhEPO to promote erythropoiesis of cancer patients should be cautious.

Cell Cycle ; drug effects ; Erythropoietin ; pharmacology ; Flow Cytometry ; Humans ; K562 Cells ; Receptors, Transferrin ; metabolism ; Recombinant Proteins

OBJECTIVETo study the expression of erythropoietin (EPO) and its receptor (EPOR) in the brain of newborn rats suffering fetal distress.

METHODSA model of fetal distress was prepared by ligating bilateral uterine arteries of the rats with full-term pregnancy for 10 minutes before cesarean sections. The expression levels of EPO and EPOR in the brain of newborn rats were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot at 0, 2, 6, 12, 24, 48, 72 hrs and 7 days after birth. Serum EPO levels were measured using ELISA simultaneously. The newborn rats born by cesarean sections which were not subjected to uterine artery ligation were used as the control group.

RESULTSThe expression of EPO protein and mRNA in brain tissues in the fetal distress group increased significantly compared with the control group 2, 6 and 12 hrs after birth (P<0.05). The expression of EPOR protein and mRNA in brain tissues in the fetal distress group increased significantly compared with the control group 2, 6, 12, 24 and 48 hrs, and 3 days after birth (P<0.05). Serum EPO levels in the fetal distress group were significantly higher than in the control group 2 hrs after birth.

CONCLUSIONSThe EPO and EPOR levels in the brain increase quickly after birth in newborn rats suffering from fetal distress. The EPOR is high expressed for a longer time than EPO. This can provide a basis for the treatment of neonatal brain damage induced by fetal distress by exogenous EPO.

Animals ; Animals, Newborn ; Brain ; metabolism ; pathology ; Erythropoietin ; blood ; genetics ; Female ; Fetal Distress ; metabolism ; Pregnancy ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptors, Erythropoietin ; blood ; genetics

OBJECTIVEErythropoietin and erythropoietin receptor (EPO-R) are expressed in many kinds of tumors. The EPO/EPO-R signaling is involved in tumor cell proliferation, invasion and angiogenesis. The aim of this study was to detect the expression of EPO-R in non-small cell lung cancer (NSCLC), and explore its correlation with angiogenesis.

METHODSThe expression patterns of EPO and EPO-R in 31 cases of NSCLC tissues were detected by immunohistochemistry, and that in benign lung lesions of 21 patients as control. To analyze the correlation of EPO/EPO-R expression patterns and clinicopathological factors. CD34 was used to label the vascular endothelial cells and calculate the microvessel density (MVD).

RESULTSThe positive rates of EPO and EPO-R expression in NSCLC were 67.7% and 96.8%, respectively, significantly higher than those in the control ones. The positive rates of EPO and EPO-R expression in adjacent tissues were 19.4% and 35.5%, and in benign lesions were 9.5% and 19.0%, respectively (P < 0.001). The expression patterns of EPO/EPO-R were not related with pTNM stage, histological type, histological grade and lymph node metastasis (P > 0.05). Increased MVD was correlated with poor differentiation, lymph node metastasis, and advanced stage.

CONCLUSIONSHigh expression of EPO/EPO-R in NSCLC patients suggest that they may be involved in tumorigenesis. EPO/EPO-R expression and MVD are closely related, and they might be an endogenous stimulant of angiogenesis during the progression of non-small cell lung cancer. It may provide evidence for clinical diagnosis.

Antigens, CD34 ; metabolism ; Carcinoma, Non-Small-Cell Lung ; blood supply ; metabolism ; pathology ; Erythropoietin ; metabolism ; Humans ; Lung Neoplasms ; blood supply ; metabolism ; pathology ; Lymphatic Metastasis ; Microvessels ; pathology ; Neoplasm Staging ; Neovascularization, Pathologic ; Receptors, Erythropoietin ; 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

This study was purposed to investigate the expression of erythropoietin receptor (EPOR) in leukemic cells and the relationship of serum erythropoietin level with anemia in acute leukemia patients, so as to provide a new theoretical basis for the cytokine therapy in acute leukemia with anemia. The EPOR in 30 AL patients was detected by using reverse transcription polymerase chain reaction (RT-PCR), the level of serum erythropoietin was detected by chemiluminescence analysis, the hemoglobin level was assayed by automatic blood counting instrument. The results indicated that EPOR was expressed in 18 out of 30 AL patients, the expression rate of EPOR in AL patients was 60%, however, but the EPOR expression rate in AML was 61.9% (13/21) and 55.6% (5/9) in ALL, the EPOR expression rate was no significant difference between AML and ALL. The EPOR expression rate was significantly lower than that in control group (86.7%) (p<0.05). The relative level of EPOR expression in AML was higher than that in ALL (p<0.05), the average level of EPOR expression in AL was significantly lower than that in control group (p<0.01). The level of sEPO in 30 AL patients was significantly higher than that in control group (p<0.01), and there was negative correlation between the levels of sEPO and Hb (p<0.01). It is concluded that the EPOR is expressed in cells of AL, but the expressive level is low. The EPOR expression rate shows no significant difference between AML and ALL. The mechanism of negative feedback to anemia in acute leukemia is intact. Anemia of acute leukemia is not completely associated with inadequate erythropoietin production and relates to hemopoiesis defect that considered as the main reason. Recombinant human erythropoietin is widely used in treatment of anemia caused by acute leukemia. Whether the treatment with rh-EPO for acute leukemia with anemia will enhance the proliferation of leukemia cells, this problem should be explored further.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anemia ; blood ; etiology ; metabolism ; Case-Control Studies ; Child ; Child, Preschool ; Erythropoietin ; blood ; Female ; Humans ; Leukemia, Myeloid, Acute ; Male ; Middle Aged ; Receptors, Erythropoietin ; metabolism ; Recombinant Proteins ; Young Adult

OBJECTIVETo study the expressions of erythropoietin receptor (EPOR) and thrombopoietin receptor (TPOR) on CD34+ CD59- and CD34+ CD59+ bone marrow (BM) cells from patients with paroxysmal nocturnal hemoglobinuria (PNH).

METHODS(1) The expressions of EPOR and TPOR on CD34+ CD59- and CD34+ CD59- BM cells from 26 PNH patients and 16 normal controls were examined by flow cytometry (FCM). (2) The mRNA expression of the EPOR and the TPOR in BM mononuclear cells (BMMNC) from 25 PNH patients and 13 normal controls were examined by RT-PCR.

RESULTS(1) The percentage of EPOR positive cells in PNH CD34+ CD59+ BMMNC [(30.67 +/- 18.30)%] was significantly higher than that in PNH CD34+ CD59- BMMNC [(8.05 +/- 3.51)%] (P < 0.01) and than that in control CD34+ CD59+ BMMNC [(8.24 +/- 6.51)%] (P < 0.01), but there was no obvious difference between the CD34+ CD59-BMMNC in PNH and CD34+ CD59+ BMMNC in control. (2) The percentage of TPOR positive cells in PNH CD34+ CD59+ BMMNC [(28.15 +/- 17.75)%] was significantly higher than that in PNH CD34+ CD59-BMMNC [(15.65 +/- 14.45)%] (P < 0.05) and than that in control CD34+ CD59+ BMMNC [(10.77 +/- .39)%] (P < 0.01), but there was no obvious difference between the CD34+ CD59- BMMNC in PNH and CD34+ CD59+ BMMNC in control. (3) There was no statistic difference in EPOR mRNA and TPOR mRNA expressions in BMMNCs between PNH patients group [(0.41 +/- 0.37) and (0.32 +/- 0.19), respectively] and control group [(0.47 +/- 0.33) and (0.40 +/- 0.29), respectively].

CONCLUSIONThe expression of EPOR and TPOR of PNH patients on BM CD34+ CD59+ cells are significantly higher than those on BM CD34+ CD59- cells. The difference may be due to abnormal transcription of both receptor coding genes.

Adult ; Bone Marrow Cells ; metabolism ; CD59 Antigens ; metabolism ; Case-Control Studies ; Cells, Cultured ; Female ; Flow Cytometry ; Hemoglobinuria, Paroxysmal ; metabolism ; Humans ; Male ; Middle Aged ; Receptors, Erythropoietin ; metabolism ; Receptors, Thrombopoietin ; metabolism ; Young Adult

OBJECTIVETo study the status of iron metabolism and erythropoietic proliferation in children with various genotypes of thalassemia.

METHODSSerum concentrations of ferritin (SF), transferrin receptor (sTfR) and erythropoietin (EPO) were measured in 158 children with thalassemia. The differences in the concentrations of the three indices among children with different genotypes of thalassemia were compared. The correlations of the hemoglobin level with sereum SF, sTfR and EPO levels were assessed.

RESULTSAmong the 158 children with thalassemia, 52(32.9%) were diagnosed with alpha-thalassemia minor, 27(17.1%) with HbH disease, 59(37.4%) with beta-thalassemia minor, 13(8.2%) with beta-thalassemia major, and 7(4.4%) with combining alpha beta thalassemia. The SF levels in children with HbH disease or beta-thalassemia major were significantly higher than those in the other thalassemia groups (P<0.01). The sTfR levels in children with beta-thalassemia major were the highest when compared with those in the other thalassemia groups (P<0.05). The EPO levels in children with beta-thalassemia major were also the highest when compared with those in the other thalassemia groups (P<0.01). There was a negative correlation between hemoglobin and EPO levels in children with HbH disease (r=-0.656, P<0.01) and beta-thalassemia major (r=-0.641; P<0.05).

CONCLUSIONSThe status of iron metabolism and erythropoietic proliferation is different in children with different genotypes of thalassemia. A combined measurement of SF, sTfR and EPO may reflect the status of erythropoietic proliferation.

Adolescent ; Child ; Child, Preschool ; Erythropoiesis ; Erythropoietin ; blood ; Female ; Ferritins ; blood ; Genotype ; Humans ; Infant ; Iron ; metabolism ; Male ; Receptors, Transferrin ; blood ; Thalassemia ; blood ; metabolism