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

The effects of erythropoietin and recombinant cytokines (G-CSF, SCF, IL-3 and GM-CSF) on colony formation and self-renewal by erythroid burst-forming units (BFU-E) and granulocyte-macrophage progenitors (CFU-GM) from mobilized peripheral blood progenitor cells (PBPCs) of the normal donors and patients were investigated. To better understand how combinations of the cytokines may be appropriate for stem cell manipulation, a model involving replating of individual BFU-E and CFU-GM colonies has been used to study the effects of cytokines on colony formation and self-renewal. Based on granulocyte colony-stimulating factor (G-CSF) and erythropoietin(EPO) alone serve as a baseline with which to compare the effects of the combinations with stem cell factor (SCF), interleukin-3 (IL-3) or granulocyte-macrophage colony-stimulating factor (GM-CSF). The results revealed that: 1. BFU-E derived from PBPCs produced a significantly great numbers of subcolonies in EPO plus IL-3 and EPO+SCF+IL-3, and a difference in EPO+SCF compared with EPO alone. 2. Compared patients to normal donors the self-renewal ability of BFU-E was not influenced after EPO plus SCF or IL-3. 3. There was a significantly increased frequency of CFU-GM in the presence of SCF, IL-3, and GM-CSF used in conjunction with G-CSF. Comparing the frequencies of CFU-GM in patients and donors, patients' PBPCs were more sensitive to G-CSF+SCF and GMix (G-CSF+SCF+IL-3+GM-CSF), especially to G-CSF alone than donors. 4. There was a significant increase in AUC (area under the curve of subcolony distribution) in the presence of G-CSF combined with other cytokines. GMix was identified as the optimal combination of cytokines for both the expansion of CFU-GM as well as the expansion of clonogenic progenitor cells. 5. Donors have a high AUC than patients, especially there was a significant increase AUC in G-CSF alone (P = 0.0067).
Cytokines ; pharmacology ; Erythroid Precursor Cells ; drug effects ; Erythropoietin ; pharmacology ; Humans ; Leukocytes, Mononuclear ; drug effects ; physiology ; Recombinant Proteins ; pharmacology ; Stem Cells ; drug effects

This study was aimed to investigate the effect of rhIL-6 and rhEPO on hepcidin mRNA expression in HepG2 cells and human primary hepatocytes, and mechanism of rhEPO in treatment of anemia of chronic disease (ACD). The HepG2 cells and human primary hepatocytes were cultured with medium containing different concentrations of rhIL-6 and rhEPO for a certain time, then mRNA was isolated and its RT-PCR was performed, the bands were photographed and analyzed by UVI band, the hepcidin and G3PDH mRNA ratio were semi-quantitatively analyzed. The expression levels of hepcidin in GepG2 cells and human primary hepatocytes at different conditions were compared. The results showed that the hepcidin mRNA expression in HepG2 cells and human primary hepatocytes could be enhanced by rhIL-6, the rhEPO could inhibit rhIL6-induced hepcidin mRAN expression. The rhEPO alone basically did not influence hepcidin mRNA expression in HepG2 cells. It is concluded that Hepcidin mRNA expression in HepG2 cells and human primary hepatocytes can be elevated by rhIL-6 with concentration- and time-dependent manner in certain range. rhEPO can inhibit this effect of rhIL-6.
Antimicrobial Cationic Peptides ; genetics ; metabolism ; Erythropoietin ; pharmacology ; Hep G2 Cells ; Hepatocytes ; drug effects ; metabolism ; Hepcidins ; Humans ; Interleukin-6 ; pharmacology ; RNA, Messenger ; genetics ; Recombinant Proteins ; pharmacology

OBJECTIVETo evaluate the effect of early application of recombinant human erythropoietin (rhEPO) on white matter development in preterm infants using fractional anisotropy (FA) of magnetic resonance diffusion tensor imaging (DTI).

METHODSA total of 81 preterm infants with gestational age ≤32 weeks, birth weight <1 500 g, and hospitalization within 24 hours after birth were randomly divided into rhEPO group (42 infants) and control group (39 infants). The infants in the rhEPO group were administered rhEPO, while those in the control group were given the same volume of normal saline. The preterm infants of both groups took examinations of head magnetic resonance imaging, diffusion-weighted imaging, and DTI at the corrected gestational age of 35-37 weeks. FA was calculated for the regions of interest in both groups.

RESULTSThere was no significant difference in the incidence of intracranial hemorrhage, periventricular leukomalacia, focal cerebral white matter damage (CWMD), and extensive CWMD between rhEPO and control groups (P>0.05). Compared with the control group, the rhEPO group showed higher FA values at the posterior limb of the internal capsule, the splenium of the corpus callosum, frontal white matter, and occipital white matter (P<0.05). There was no significant difference in FA values at the parietal white matter, thalamus, lenticular nucleus, and caudate nucleus between the two groups (P>0.05).

CONCLUSIONSEarly application of rhEPO has a neuroprotective effect on white matter development in preterm infants.

Diffusion Tensor Imaging ; Erythropoietin ; pharmacology ; Female ; Humans ; Infant, Newborn ; Infant, Premature ; Male ; Neuroprotective Agents ; pharmacology ; Recombinant Proteins ; pharmacology ; White Matter ; drug effects ; growth & development

OBJECTIVERecent studies have shown cardiac protection effects of erythropoietin (EPO). The present experiment was designed to investigate the effects of EPO on TGF-beta1, nitric oxide synthase (NOS), collagen contents induced by angiotensin II (Ang II) in rat cardiac fibroblasts (CFs) and explore the roles of PI3-K/Akt signaling pathway on related effects.

METHODSNeonatal rat CFs was isolated by collagenase and trypsinase digestion methods. PBS, EPO, Ang II in the absence or presence of LY294002, an inhibitor of PI3-K, or L-NAME, an inhibitor of NOS, were added to CFs and cultured for 24 hours. The concentration of collagen I and collagen III in culture medium were quantitated by ELISA. The levels of nitric oxide (NO) and the activities of NOS as well as NOS isoforms were measured by chemical enzymic method. Western blot was applied to detecting the protein expressions of Akt, p-Akt, eNOS, iNOS, and TGF-beta1.

RESULTSThe concentrations of collagen I and collagen III in CFs culture medium were significantly increased while the level of NO was significantly decreased by Ang II and these changes were significantly suppressed by EPO in a dose dependent manner. The effects of EPO on eNOS and NO could be blocked by LY294002. L-NAME could block EPO's effect on NO but not on the eNOS expression. The suppression effects on expressions of TGF-beta1 and collagen by Ang II in CFs were blocked by both LY294002 and L-NAME.

CONCLUSIONEPO suppresses the upregulated expressions of TGF-beta1 and increased production of collagen induced by Ang II through activating the PI3-K/Akt signaling pathway in neonatal rat CFs.

Angiotensin II ; pharmacology ; Animals ; Cells, Cultured ; Collagen ; metabolism ; Erythropoietin ; pharmacology ; Myoblasts, Cardiac ; drug effects ; metabolism ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; Transforming Growth Factor beta1 ; metabolism

To study whether recombinant human erythropoietin (rhEPO) reduces neuronal apoptosis through inhibiting over-expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in nucleus induced by brain ischemia/reperfusion in rats, 48 adult Sprague-Dawley rats were randomly divided into 3 groups: sham, saline and EPO groups. Animal models of brain ischemia/reperfusion were established by middle cerebral artery occlusion in rats. The effects of EPO on the sizes of ischemia tissue were observed by TTC staining. The over-expression of GAPDH in nucleus was detected by Hoechst-33258 and anti-GAPDH antibody double staining. The neuronal apoptosis in penumbral was detected by Nissl's staining and Hoechst-33258 immunofluorescence, respectively. The results showed that rhEPO treatment (3 000 U/kg, three times daily, i.p.) apparently reduced the sizes of infarct brain tissue in ischemia/reperfusion rats. rhEPO inhibited over-expression of GAPDH in nucleus of apoptotic neurons. In the meantime rhEPO decreased the number of apoptotic neurons in ischemia/reperfusion rats. These results suggest that rhEPO may induced reduction of neuronal apoptosis in penumbra may be through inhibiting over-expression of GAPDH in nucleus of apoptotic neurons induced by ischemia/reperfusion. Reduction of GAPDH over-expression in nucleus may play a pivotal role in EPO inhibiting neuronal apoptosis in cerebral ischemia/reperfusion rats, providing experimental evidence for EPO neuro-protecting effects against ischemia/reperfusion.
Animals ; Apoptosis ; Brain ; enzymology ; pathology ; Brain Ischemia ; pathology ; Erythropoietin ; pharmacology ; Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) ; metabolism ; Humans ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; pharmacology ; Reperfusion Injury ; pathology

OBJECTIVETo investigate the effect of recombinant human erythropoietin (rhEPO) on the expression of bcl-2 protein in the retina of rabbits with acute high intraocular pressure and explore the mechanism underlying the protective effect of rhEPO on the retina against ischemia-reperfusion injury.

METHODSrhEPO was injected subcutaneously in the ear of a rabbit model of acute high intraocular pressure induced by physiological saline perfusion into the anterior chamber. Bcl-2 protein expression in the retina of the rabbits was observed by immunohistochemical staining on days 1, 3, 7, and 14 after retinal ischemia-reperfusion and compared with that in normal rabbits and untreated rabbit models.

RESULTSbcl-2-positive cells were observed in the retina of normal rabbits with a mean positive cell number of 10.5-/+1.2 in each high-power visual field. Compared with that in the normal control group, the number of the positive cells decreased significantly in both the model group and EPO group (P<0.05, P<0.01), but the latter group showed a significantly greater number than the former (P<0.05 at day 7 and P<0.01 at day 14).

CONCLUSIONSystemic administration of rhEPO can up-regulate the expression of bcl-2 protein in the retina of rabbits with acute high intraocular pressure, which is probably one of the mechanisms for the protective effect of rhEPO on the retina against ischemia-reperfusion injury.

Animals ; Erythropoietin ; pharmacology ; therapeutic use ; Female ; Humans ; Male ; Ocular Hypertension ; drug therapy ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rabbits ; Random Allocation ; Recombinant Proteins ; Retina ; metabolism

OBJECTIVETo observe the effect of recombinant human erythropoietin (rHuEPO) on immune function of premature rats.

METHODSRHuEPO of 250 IU/(kg.t) or 500 IU/(kg.t) was administered to premature rats every other day for nineteen days. The control premature rats were received normal saline. The changes of hemoglobin (Hb), serum erythropoietin (EPO), red blood cell (RBC) immune function, T lymphocyte proliferative responsiveness, and production of tumor necrosis factor alpha (TNF-alpha) were observed.

RESULTSPremature rats showed lower levels on Hb, RBC immune function, T cell responsiveness and production of TNF-alpha compared with mature rats at birth. The postnatal declines of Hb and RBC immune function were lessened in the treated groups of premature rats, the higher dosage group of 500 IU/(kg.t) was more significant than the lower dosage group of 250 IU/(kg.t). When experiments were over, Hb of control premature rats was (7.72 +/- 0.89) g/dl, Hb of premature rats received 500 IU/(kg.t) was (10.08 +/- 0.90) g/dl (P < 0.01). C3b-R% of control premature rats was (11.00 +/- 0.95)%, C3b-R% of premature rats received 500 IU/(kg.t) was (17.75 +/- 1.04)% (P < 0.01). IC-R% in control premature rats was (12.83 +/- 1.33)%, IC-R% of premature rats received 500 IU/(kg.t) was (10.50 +/- 1.67)% (P < 0.01). The postnatal rise of T cell responsiveness and the production of TNF-alpha in premature rats increased in the treated groups, which was more significant in the higher dosage group of 500 IU/(kg.t) than in the lower dosage group of 250 IU/(kg.t). The OD index of control premature rats was 0.159 +/- 0.014, the OD index of premature rats received 500 IU/(kg.t) was 0.354 +/- 0.050 (P < 0.01). TNF-alpha in control premature rats was (0.270 +/- 0.014) ng/ml, TNF-alpha of premature rats received 500 IU/(kg.t) was (0.415 +/- 0.010) ng/ml (P < 0.01).

CONCLUSIONS(1) Premature rats had lower RBC immune function and T cell responsiveness and underproduction of TNF-alpha at birth. (2) Premature rats had an improvement with the RBC immune function after rHuEPO administration. (3) Premature rats had improvements with T cell responsiveness and TNF-alpha after rHuEPO administration, and there was a positive correction between the RBC immune function and T cell responsiveness with the production of TNF-alpha.

Animals ; Erythrocyte Count ; Erythrocytes ; drug effects ; immunology ; Erythropoietin ; blood ; pharmacology ; Female ; Hemoglobins ; analysis ; Pregnancy ; Rats ; Recombinant Proteins ; T-Lymphocytes ; drug effects ; immunology ; Tumor Necrosis Factor-alpha ; analysis

This study was aimed to investigate the effects of recombinant human erythropoietin (rhEPO) on proliferation of human bone marrow-derived mesenchymal stem cells (MSCs) in vitro. The aspirates of the bone marrow from healty volunteers were seeded in culture medium. Then MSCs were isolated according to characteristics adhering to the plastics. After three passages in culture, bone marrow-derived adherent cells were identified by growing morphological features, cell surface antigens and differentiation into multi-lineages. Then P3-MSCs which had been identified were incubated with different concentrations of rhEPO (0.5, 1, 5, 10 and 50 U/ml). Subsequently, proliferation of MSCs was measured by MTT assay, as well as cell counts. At the same time, cell cycle was detected by flow cytometry (FCM). The results indicated that the expressions of CD90 and CD105 in P3 bone marrow-derived adherent cells were positive, while the expressions of CD34 and CD45 were negative, and these cells could differentiate into adipocytes, osteocytes and chondrocytes in induction media. MTT assay showed that the optical density (OD) of group treated with EPO was significantly higher than that in the control group (p<0.05), and the group treated with 50 U/ml EPO achieved the most predominant effects. The results of cell count were coincident with that of MTT assay. Furthermore, the cell cycle analysis by FCM revealed that rhEPO could relatively decrease the cell ratio in G0/G1 phase, and increase the cell ratio in S and G2/M phases. As compared with the control group, all those differences were statistically significant (p<0.01). It is concluded that erythropoietin can promote proliferation of human bone marrow mesenchymal stem cells in vitro, which may be correlated with the increased entry into S and M phases of cell cycle of MSCs adjusted by EPO.
Bone Marrow Cells ; cytology ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Culture Media ; Erythropoietin ; pharmacology ; Humans ; Mesenchymal Stromal Cells ; cytology ; Recombinant Proteins

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