Evaluation of the effects of erythropoietin and interleukin-6 in rats submitted to acute spinal cord injury

OBJECTIVE: To evaluate the effects of interleukin-6 (IL-6) and erythropoietin (EPO) in experimental acute spinal cord injury (SCI) in rats. METHODS: Using standardized equipment, namely, a New York University (NYU) Impactor, a SCI was produced in 50 Wistar rats using a 10-g weight drop from a 12.5-mm height. The rats were divided into the following 5 groups of 10 animals each: "Group EPO", treated with erythropoietin only; "Group EPO + IL-6", treated with both substances; "Group IL-6", receiving IL-6 administration only; "Group Placebo", receiving a placebo solution; and "Group Sham", submitted to an incomplete procedure (only laminectomy, without SCI). All drugs and the placebo solution were administered intraperitoneally for three weeks. The animals were followed up for 42 days. Functional motor recovery was monitored by the Basso, Beattie, and Bresnahan (BBB) scale on days 2, 7, 14, 21, 28, 35 and 42. Motor-evoked potential tests were performed on the 42nd day. Histological analysis was performed after euthanasia. RESULTS: The group receiving EPO exhibited superior functional motor results on the BBB scale. IL-6 administration alone was not superior to the placebo treatment, and the IL-6 combination with EPO yielded worse results than did EPO alone. CONCLUSIONS: Using EPO after acute SCI in rats yielded benefits in functional recovery. The combination of EPO and IL-6 showed benefits, but with inferior results compared to those of isolated EPO; moreover, isolated use of IL-6 resulted in no benefit.

Neuroprotective effects of erythropoietin on rat retinas subjected to oligemia

OBJECTIVES: Erythropoietin may have neuroprotective potential after ischemia of the central nervous system. Here, we conducted a study to characterize the protective effects of erythropoietin on retinal ganglion cells and gliotic reactions in an experimentally induced oligemia model. METHODS: Rats were subjected to global oligemia by bilateral common carotid artery occlusion and then received either vehicle or erythropoietin via intravitreal injection after 48 h; they were euthanized one week after the injection. The densities of retinal ganglion cells and contents of glial fibrillary acidic protein (astrocytes/Müller cells) and cluster of differentiation 68 clone ED1 (microglia/macrophages), assessed by fluorescence intensity, were evaluated in frozen retinal sections by immunofluorescence and epifluorescence microscopy. RESULTS: Retinal ganglion cells were nearly undetectable one week after oligemia compared with the sham controls; however, these cells were partially preserved in erythropoietin-treated retinas. The contents of glial fibrillary acidic protein and cluster of differentiation 68 clone ED1, markers for reactive gliosis, were significantly higher in retinas after bilateral common carotid artery occlusion than those in both sham and erythropoietin-treated retinas. CONCLUSIONS: The number of partially preserved retinal ganglion cells in the erythropoietin-treated group suggests that erythropoietin exerts a neuroprotective effect on oligemic/ischemic retinas. This effect could be related to the down-modulation of glial reactivity, usually observed in hypoxic conditions, clinically observed during glaucoma or retinal artery occlusion conditions. Therefore, glial reactivity may enhance neurodegeneration in hypoxic conditions, like normal-tension glaucoma and retinal ischemia, and erythropoietin is thus a candidate to be clinically applied after the detection of decreased retinal blood flow.

Effects of ganglioside G(M1) and erythropoietin on spinal cord lesions in rats: functional and histological evaluations

OBJECTIVE: To evaluate the functional and histological effects of ganglioside G(M1) and erythropoietin after experimental spinal cord contusion injury. METHODS: Fifty male Wistar rats underwent experimental spinal cord lesioning using an NYU-Impactor device and were randomly divided into the following groups, which received treatment intraperitoneally. The G(M1) group received ganglioside G(M1) (30 mg/kg); the erythropoietin group received erythropoietin (1000 IU/kg); the combined group received both drugs; and the saline group received saline (0.9%) as a control. A fifth group was the laminectomy group, in which the animals were subjected to laminectomy alone, without spinal lesioning or treatment. The animals were evaluated according to the Basso, Beattie and Bresnahan (BBB) scale, motor evoked potential recordings and, after euthanasia, histological analysis of spinal cord tissue. RESULTS: The erythropoietin group had higher BBB scores than the G(M1) group. The combined group had the highest BBB scores, and the saline group had the lowest BBB scores. No significant difference in latency was observed between the three groups that underwent spinal cord lesioning and intervention. However, the combined group showed a significantly higher signal amplitude than the other treatment groups or the saline group (p<0.01). Histological tissue analysis showed no significant difference between the groups. Axonal index was significantly enhanced in the combined group than any other intervention (p<0.01). CONCLUSION: G(M1) and erythropoietin exert therapeutic effects on axonal regeneration and electrophysiological and motor functions in rats subjected to experimental spinal cord lesioning and administering these two substances in combination potentiates their effects.

Effects of erythropoietin on electrocardiogram changes in carbon monoxide poisoning: an experimental study in rats

The aim of this study was to define the electrocardiogram [ECG] changes following the moderate to severe CO intoxication in rats, and also evaluating the effect of erythropoietin [EPO] on observed cardiac disturbances. The growing literature on erythropoietin effect on cardiac ischemia led us to question its effect on cardiotoxicity due to the carbon monoxide poisoning. Wistar rats were exposed to three different concentrations of CO [250 PPM, 1000 PPM or 3000 PPM]. EPO was administrated [5000 IU/Kg, intraperitoneal injection] at the end of CO exposure and then the animals were re-oxygenated with ambient air. Subsequently ECG recording, heart rate and carboxyhemoglobin values were evaluated. ECG changes following the CO intoxication included ST segment elevation and depression, T wave inversion and first-degree AV block. Ischemic ECG changes reduced significantly in EPO-treated animals. In the present study, for the first time, EPO was investigated for the management of cardiac complications due to the CO poisoning. Our results showed that EPO could inhibit ischemic changes of ECG after the CO poisoning

Early Sustained Injections of Erythropoietin Improve Angiogenesis and Restoration of Perfusion in the Ischemic Mouse Hindlimb

This study was conducted to investigate the effects of erythropoietin (Epo) on both acute and chronic limb ischemia (ALI and CLI) and to evaluate the differences in mechanisms according to the method of Epo administration. Hindlimb ischemia was made in BALB/c mice with femoral artery ligation. The mice were divided into four groups: Group 1 (control, no treatment), Group 2 (ALI, early multiple doses), Group 3 (ALI, early single high dose), Group 4 (CLI, late multiple doses). Blood flow ratio significantly increased in Group 2 in 4 weeks. Expression of pAkt and Erythropoietin receptor were significantly higher in Group 2 on postoperative day (POD) 7. The number of CD31- and vascular endothelial growth factor-positive cells were significantly higher in Group 2 on POD 7 and 56. Group 3 and 4 showed a tendency of higher cell counts than the control. The early sustained Epo was effective in improving blood flow through angiogenesis. In chronic phase, weekly multiple dosing of Epo induced angiogenesis, however, the blood flow ratio did not increase significantly. The results of this study suggest that Epo administration during the acute phase followed by maintenance for several days may be important for increasing blood flow and angiogenesis.

The use of genes for performance enhancement: doping or therapy?

Recent biotechnological advances have permitted the manipulation of genetic sequences to treat several diseases in a process called gene therapy. However, the advance of gene therapy has opened the door to the possibility of using genetic manipulation (GM) to enhance athletic performance. In such ‘gene doping’, exogenous genetic sequences are inserted into a specific tissue, altering cellular gene activity or leading to the expression of a protein product. The exogenous genes most likely to be utilized for gene doping include erythropoietin (EPO), vascular endothelial growth factor (VEGF), insulin-like growth factor type 1 (IGF-1), myostatin antagonists, and endorphin. However, many other genes could also be used, such as those involved in glucose metabolic pathways. Because gene doping would be very difficult to detect, it is inherently very attractive for those involved in sports who are prepared to cheat. Moreover, the field of gene therapy is constantly and rapidly progressing, and this is likely to generate many new possibilities for gene doping. Thus, as part of the general fight against all forms of doping, it will be necessary to develop and continually improve means of detecting exogenous gene sequences (or their products) in athletes. Nevertheless, some bioethicists have argued for a liberal approach to gene doping.

Erythropoietin Attenuates Brain Injury, Subventricular Zone Expansion, and Sensorimotor Deficits in Hypoxic-Ischemic Neonatal Rats

The aim of this study was to investigate the effect of erythropoietin (EPO) on histological brain injury, subventricular zone (SVZ) expansion, and sensorimotor function deficits induced by hypoxia-ischemia (HI) in newborn rat pups. Seven-day-old male rat pups were divided into six groups: normoxia control, normoxia EPO, hypoxia control, hypoxia EPO, HI control, and HI EPO group. Sham surgery or HI was performed in all animals. HI was induced by ligation of the right common carotid artery followed by 90 min of hypoxia with 8% oxygen. Recombinant human EPO 3 U/g or saline was administered intraperitoneally, immediately, at 24- and 48-hr after insult. At two weeks after insult, animals were challenged with cylinder-rearing test for evaluating forelimb asymmetry to determine sensorimotor function. All animals were then sacrificed for volumetric analysis of the cerebral hemispheres and the SVZ. The saline-treated HI rats showed marked asymmetry by preferential use of the non-impaired, ipsilateral paw in the cylinder-rearing test. Volumetric analysis of brains revealed significantly decreased preserved ipsilateral hemispheric volume and increased ipsilateral SVZ volume compared with the sham-operated animals. Treatment of EPO significantly improved forelimb asymmetry and preserved ipsilateral hemispheric volume along with decreased expansion of ipsilateral SVZ following HI compared to the saline-treated HI rats. These results support the use of EPO as a candidate drug for treatment of neonatal hypoxic-ischemic brain damage.

Erythropoietin preconditioning on hippocampus neuronal apoptosis following status epilepticus induced by Li-pilocarpine in rats through anti-caspase-3 expression.

Selective neuronal loss following status epilepticus (SE) was first described just under 100 years ago. The acute pathology following SE was shown to be 'ischemic cell change' and was assumed to arise through hypoxia/ischemia. Recently, erythropoietin (Epo) has been shown to have potent anti-apoptosis activity in central nervous system neurons in animal models of ischaemic injury. AIMS: In this report, in order to determine Epo preconditioning on hippocampus neuronal apoptosis, we examined caspase-3 expression following SE caused by Li-pilocarpine in rats. SETTINGS AND DESIGN: Animals were classified into three groups: EP group (pilocarpine group), rhEpo-pilocarpine group and control group. Four hours after preconditioning with Epo intraperitoneally, pilocarpine hydrochloride was administered intraperitoneally and observed for behavioral manifestations of SE. The animals were sacrificed at one hour after SE onset. MATERIALS AND METHODS: At the above-mentioned time point, animals were deeply anesthetized and were perfused through the left ventricle. Detection of hippocampus neuronal apoptosis was performed with caspase-3 immunohistochemical technique on three groups. To further confirm which cell population upregulates caspase-3, brain sections were stained for NeuN (green) and caspase-3 (red). STATISTICAL ANALYSIS: ANOVA and Fisher's post hoc test was used. RESULTS: Quatification of hippocampus neurons revealed that the number of caspase-3-positive cells in the CA1/CA3 area and dentate gyrus(DG) of three groups had a significant difference. In comparison with control group, there was an increase by 74% and 534%, 42% and 272% in the CA1/CA3 area and DG of EP group and rhEpo-treated group respectively. There was a decrease by 18% and 26% in the CA1/CA3 area and DG of rhEpo-treated group compared with those in EP group. In addition, colocalization of caspase-3 with NeuN was shown. CONCLUSIONS: Systemic rhEpo therapy reduced caspase-3 expression in SE induced by Li-pilocarpine.

Gene expression in uremic left ventricular hypertrophy: effects of hypertension andanemia

Hypertension and anemia may be causes of left ventricular hypertrophy (LVH) in uremia but the molecular mechanism is not known. Uremia was induced in male Spraugue Dawley rats by 5/6 nephrectomy. The following groups of rats were studied for 6 weeks; uremic rats (U) fed ad. lib., control rats (C) pair-fed with U, U rats given hydralazine (100 mg/kg/day) (UH), U rats given erythropoietin (48U/kg/week, i.p.) (UE). Both diastolic and mean arterial pressures are higher (P<0.01) in U and UE compared with C whereas both pressures in UH were normalized. Hemoglobin in U was lower than in C, and was normalized in UE. U, UH and UE had higher heart weight/body weight ratios (HW/BW) as well as left ventricular weight/body weight ratios (LV/BW) compared with C (P<0.01). Compared with U, UH has lower HW/BW and LV/BW (P <0.05) and UE has normal HW/BW but lower LV/BW than U (P<0.05). To see if the gene expression in uremic LVH is similar to that described in pressure overload LVH in which mRNA levels of angiotensin converting enzyme (ACE), transforming growth factor-beta1 (TGF-beta1), atrial natriuretic factors (ANF) and skeletal alpha-actin were increased, we measured these mRNA levels by Northern analysis. TGF-beta, ACE and alpha-actin mRNA levels were not changed in all 4 groups. ANF mRNA in U and UE was increased 3 fold over C, and normalized in UH. Treatment of anemia with erythropoietin improved uremic LVH but did not change ANF mRNA; whereas treatment of hypertension with hydralazine normalized ANF mRNA but did not completely correct uremic LVH. Thus, gene expression in uremic LVH is distinct from that in pressure- overload LVH, suggesting that other unidentified factor(s) might be involved in uremic LVH.

Uso precoz de la eritropoyetina en la prevención de la anemia del prematuro / Early erythropoietin use for the prevention of anemia in very low birth weight newborns

Background: Anemia is common among very low birth weight newborns and requires frequent blood tranfusions. Erythropoietin was been reported to be useful in the prevention of this anemia. Aim: To asses the benefits of early (before the third week of life) Human recombinant Erythropoietin (r-EPO) administration to reduce the requirement of blood tranfusions in very low birth weight newborns. Patients and methods: sixty newborns under 1500g of birthweight were randomly assigned to recive r-EPO (n=29) or placebo (n=31) three times per week, during four weeks. Packed red cell volume and reticulocyte counts were measured weekly. Serum erythropoietin was measured prior to eigth dose. Transfusion requirements were recorded. Results: r-EPO reduced transfusions from 1.41 ñ 1.1 to 0.69 ñ 1 transfusions/newborns (p<0.001). At the fourth week of treatment, reticulocyte count was 14.8 ñ 7 and 6.4 ñ 4.9 percent in the active treatment group and placebo group respectively (p<0.001). Conclusions: r-EPO reduces the requrement of transfusions in low birth weight infants

Erythropoietin does not affect nitric oxide system in rats with chronic renal failure

We investigated to see whether an altered role of nitric oxide (NO) system is involved in erythropoietin (EPO)-induced hypertension in chronic renal failure (CRF). Male Sprague-Dawley rats were five-sixths nephrectomized to induce CRF. Six weeks after the operation, EPO or vehicle was injected for another 6 weeks. Plasma and urine nitrite/nitrate (NOx) levels were determined. Expression of NO synthase (NOS) proteins in the aortae and kidneys were also determined. In addition, the isometric tension of isolated aorta in response to acetylcholine and nitroprusside was examined. Blood pressure progressively rose in CRF groups, the degree of which was augmented by EPO treatment. Plasma NOx levels did not differ among the groups, while urine NOx levels were lower in CRF groups. Endothelial NOS expression was lower in the kidney and aorta in CRF rats, which was not further affected by EPO-treatment. The inducible NOS expression in the kidney and aorta was not different among the groups. Acetylcholine and sodium nitroprusside caused dose-dependent relaxations of aortic rings, the degree of which was not altered by EPO-treatment. Taken together, EPO-treatment aggravates hypertension in CRF, but altered role of NO system may not be involved.

Anabólicos en producción pecuaria: ¿un riesgo para la salud del consumidor? / Use of anabolics in livestock: a health risk for the consumer?

En la actualidad, el mejoramiento en la eficiencia de los procesos de producción de alimentos ha llegado a ser muy importante, alcanzando también este interés a los animales de consumo. Esto ha llevado a combinar los conocimientos científico-biológicos en el área del crecimiento y desarrollo animal con factores económicos. Se ha encontrado que el empleo de ciertos compuestos denominados anabólicos (cuya acción es semejante a la acción de algunas hormonas) puede contribuir a aumentar la deficiencia en la producción de músculo comestible; esto significa aumento de la masa muscular a menor costo. En este artículo se revisa los anabólicos existentes, su mecanismo de acción, la normativa vigente para el uso de estos compuestos, en Chile y otros países, y los posibles riesgos para el consumidor que ingiere carnes que contienen residuos de anabólicos

Citocina. ¿La terapéutica del futuro? / Citokines. The therapy in the future?

Se definen qué son las citocinas y se describe el papel de la interleucina-1 como un ejemplo de las fuciones que desempeñan. Actualmente se han encontrado más de 40 citocinas que se han agrupado en 1) factores de crecimiento, 2) interleucinas, 3) interferones, 4) quimiocinas y 5) otras. Hoy en día, mediante transfección genética, se han preparado 11 citocinas para aplicación terapéutica; de éstas, la eritropoyetina, el factor estimulante de colonias granulocito-monocito y el factor estimulante de colonias granulocito-monocito y el factor estimulante de colonias de granulocitos se utilizan con buen éxito para estimular la producción de glóbulos rojos, granulocitos y de monocitos en algunas patologías con daño a la médula ósea. Después de varios años de aplicación clínica, el uso de los interferones alfa, beta y gamma se han visto limitados a infecciones como la hepatitis B o C y algunos tipos de cáncer como la leucemia de células peludas y la leucemia granolocítica crónica. Las otras citocinas, como las interleucinas 2, 3, 4, 6 y el factor estimulante de colonias de monocitos, empiezan a mostrar su utilidad terapéutica en algunos ensayos clínicos. Se espera que en el futuro algunas de ellas, solas o combinadas con otras u otros activadores inmunológicos curen enfermedades como el síndrome de inmunodeficiencia adquirida o el cáncer

Blockade of the in vitro effects of testosterone and erythropoietin on Cfu-E and Bfu-E proliferation by pretreatment of the donor rats with cyproterone and flutamide

Erythropoietin is obligatory to support the terminal proliferation and differentiation of erythroid cells but it is not the only agent in modulating red cell production. Previously, we have shown that Testosterone enhances erythropoiesis, at least in part, by increasing renal erythropoietin production. Testosterone may also influence directly the behavior of the erythroid progenitor cells increasing erythroid stem cell proliferation. To gain further insight into the role of testosterone in regulation of erythropoiesis and its interactions with erythropoietin, we studied the effect of testosterone and erythropoietin, using clonal cultures of erythropietic progenitors, to observe CFU-E and late and early BFU-E colonies proliferation from bone marrow cells of donor rats pretreated for 2 days with the androgen antagonists cyproterone (10 mg/Kg/day) and flutamide (160 mg/Kg/day). Specific nuclear receptors for testosterone were demonstrated in marrow erythroid cells. Then, erythroid progenitors may come with their androgen receptors blocked by pretreatment. Cultures were prepared using the methylcellulose technique containing a standard dose of erythropoietin (250 mu/ml) or testosterone (10(-7) M). Results obtained demonstrate that testosterone produced a significant stimulation on CFU-E and BFU-E colony formation. A dose effect correlation was apparent. Testosterone enhances proliferation of late BFU-E more than CFU-E and produce only a slight augmentation of early BFU-E. As expected, erythropoietin markedly stimulate all erythroid colony growth, mainly CFU-E. The effects of testosterone were completely abolished in cultures from bone marrow cells of rats pretreated with cyproterone and flutamide. Activation of the specific androgen nuclear receptors in erythroid cells appears to be necessary for testosterone to develop the erythropoietic effect. Surprisingly, the effects of erythropoietin on erythroid colonies proliferation were also completely blocked by pretreatment with flutamide and partially blocked by pretreatment with cyproterone. Right now, we do not have a satisfactory explanation regarding inhibition of the effects of erythropoietin by pretreatment to marrow donor rats with the androgen antagonists. In conclusion, we postulate triggering late BFU-E cells, a marrow erythropoietin responsive cell population, into active cell cycle, as well as by increasing blood erythropoietin concentration.

Efeitos da eritropoetina na hemodinâmica renal / Effects of erythropoietin in renal hemodynamics

Apesar das evidências indicarem que o tratamento com eritropoetina nao altera a funçäo renal de pacientes renais crônicos em pré-diálise ou diálise, os dados experimentais provenientes de ratos insuficientes renais crônicos indicam que a eritropoetina induz perda progressiva da funçao renal, aumento no índice de esclerose e proteinúria. Em ratos normais, a eritropoetina induz vasodilataçao arteriolar, hiperfiltraçäo glomerular e outras alteraçöes na hemodinâmica glomerular. Considerando os dados sobre os efeitos da policitemia na funçao renal, parece mais evidente que os efeitos desta droga sejam de natureza reológica do que de natureza direta, já que as concentraçöes que determinam açao direta säo superiores às concentraçöes fisiológicas ou terapêuticas.