RESUMEN
Expression of mRNA for adenosine receptor subtypes A(1), A(2a), A(2b), and A(3) in normal and lipopolysaccharide (LPS)-activated murine RAW 264.7 macrophages has been investigated using the method of quantitative real-time polymerase chain reaction. The results have shown a very low, unquantifiable expression of adenosine A(1) receptor mRNA in both normal and LPS-activated macrophages. The other three adenosine receptor mRNAs have been found to be expressed at various but always quantifiable levels. Activation of the macrophages by LPS induced upregulation of the expression of adenosine receptor A(2a) and A(2b) mRNA, whereas the expression of adenosine receptor A(3) mRNA was downregulated. Unstimulated macrophages exhibited a high expression of the A(2b) adenosine receptor mRNA. The findings are discussed from the point of view of the antiinflammatory and hematopoiesis-stimulating roles of the adenosine receptor signaling.
Asunto(s)
Hematopoyesis , Lipopolisacáridos/farmacología , Activación de Macrófagos , Macrófagos/metabolismo , ARN Mensajero/metabolismo , Receptores Purinérgicos P1/genética , Animales , Línea Celular , Regulación de la Expresión Génica , Hematopoyesis/efectos de los fármacos , Hematopoyesis/genética , Activación de Macrófagos/efectos de los fármacos , Activación de Macrófagos/genética , Macrófagos/efectos de los fármacos , Ratones , Reacción en Cadena de la Polimerasa , Receptor de Adenosina A1/genética , Receptor de Adenosina A2A/genética , Receptor de Adenosina A2B/genética , Receptor de Adenosina A3/genética , Receptores Purinérgicos P1/efectos de los fármacos , Factores de TiempoRESUMEN
Four mouse bone marrow or thymus cell populations, namely granulopoietic/monocytopoietic, erythropoietic, B-lymphopoietic, and T-lymphopoietic precursor cells have been assayed by RT-PCR technique for the presence and relative amounts of adenosine A(1), A(2a), A(2b), and A(3) receptor mRNA. It has been found that (i) all four populations studied express all four adenosine receptor subtypes, (ii) the A(1), receptor is the least expressed in all populations studied, (iii) the A(3) receptor is markedly expressed in the populations of granulopoietic/monocytopoietic and erythropoietic cells, (iv) the A(2a) receptor is markedly expressed in the populations of B-lymphopoietic and T-lymphopoietic cells, and v) the A(2b) receptor does not predominate in any of the precursor cells studied. Our data offer a new possibility for the assessment of the readiness of these cells to respond, by receptor-mediated mechanisms, to adenosine or its analogs present in the tissues as a result of endogenous processes and/or following their administration.
Asunto(s)
Hematopoyesis , Células Madre Hematopoyéticas/metabolismo , ARN Mensajero/metabolismo , Receptores Purinérgicos P1/genética , Animales , Separación Celular , Femenino , Regulación de la Expresión Génica , Hematopoyesis/genética , Ratones , Ratones Endogámicos C57BL , Reacción en Cadena de la Polimerasa , Receptor de Adenosina A1/genética , Receptor de Adenosina A2A/genética , Receptor de Adenosina A2B/genética , Receptor de Adenosina A3/genéticaRESUMEN
Adenosine A(3) receptor agonist N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide (IB-MECA) has been tested from the point of view of potentiating the effects of hematopoietic growth factors interleukin-3 (IL-3), stem cell factor (SCF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and granulocyte colony-stimulating factor (G-CSF) on the growth of hematopoietic progenitor cells for granulocytes and macrophages (GM-CFC) in suspension of normal mouse bone marrow cells in vitro. IB-MECA alone induced no GM-CFC growth. Significant elevation of numbers of GM-CFC evoked by the combinations of IB-MECA with IL-3, SCF, or GM-CSF as compared with these growth factors alone has been noted. Combination of IB-MECA with G-CSF did not induce significantly higher numbers of GM-CFC in comparison with G-CSF alone. Joint action of three drugs, namely of IB-MECA + IL-3 + GM-CSF, produced significantly higher numbers of GM-CFC in comparison with the combinations of IB-MECA + IL-3, IB-MECA + GM-CSF, or IL-3 + GM-CSF. These results give evidence of a significant role of selective activation of adenosine A(3) receptors in stimulation of the growth of granulocyte/ macrophage hematopoietic progenitor cells.
Asunto(s)
Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Hematopoyéticas/metabolismo , Factor de Crecimiento de Hepatocito/farmacología , Interleucina-3/farmacología , Receptor de Adenosina A3/metabolismo , Adenosina/análogos & derivados , Adenosina/farmacología , Animales , División Celular/efectos de los fármacos , Células Cultivadas , Sinergismo Farmacológico , Granulocitos/citología , Células Madre Hematopoyéticas/citología , Técnicas In Vitro , Macrófagos/citología , Masculino , Ratones , Ratones EndogámicosRESUMEN
Meloxicam, a selective inhibitor of cyclooxygenase 2, was tested to determine its ability to modulate hematopoiesis and to influence survival of mid-lethally gamma-irradiated mice. A single dose of meloxicam (20 mg/kg) administered to mice intraperitoneally 1 h before irradiation was shown to enhance serum levels of granulocyte colony-stimulating factor (G-CSF) during the first 24 h after irradiation, to elevate numbers of granulocytic precursor cells in bone marrow and granulocyte counts in peripheral blood on day 10 after irradiation, and to increase 30-day survival of these mice. The results provide new evidence for the protective ability of meloxicam administration to mice irradiated with mid-lethal doses and contribute to the understanding of the mechanisms of this meloxicam action by drawing attention to the possible role of increased endogenous G-CSF production.
Asunto(s)
Inhibidores de la Ciclooxigenasa 2/farmacología , Factor Estimulante de Colonias de Granulocitos/biosíntesis , Protectores contra Radiación/farmacología , Tiazinas/farmacología , Tiazoles/farmacología , Animales , Hematopoyesis/efectos de la radiación , Masculino , Meloxicam , RatonesRESUMEN
Hematopoiesis-modulating action of meloxicam, a cyclooxyge-nase-2 inhibitor, has been evaluated in mice. Increased serum level of granulocyte colony-stimulating factor (G-CSF) after meloxicam administration has been found in sublethally gamma-irradiated animals. In further experiments hematopoiesis-stimulating effects of meloxicam and G-CSF given alone or in combination have been investigated. Granulocyte/macrophage progenitor cells counts were used to monitor these effects. Meloxicam and exogenous G-CSF did not act synergistically when given in combination, but could be mutually substituted during their repeated administration. The results suggest a promising possibility of using meloxicam as an auxiliary drug reducing the high costs of G-CSF therapy of myelosuppression.
Asunto(s)
Médula Ósea/efectos de los fármacos , Inhibidores de la Ciclooxigenasa 2/farmacología , Factor Estimulante de Colonias de Granulocitos/sangre , Hematopoyesis/efectos de los fármacos , Tiazinas/farmacología , Tiazoles/farmacología , Animales , Médula Ósea/efectos de la radiación , Diferenciación Celular , Interacciones Farmacológicas , Quimioterapia Combinada , Factor Estimulante de Colonias de Granulocitos/administración & dosificación , Factor Estimulante de Colonias de Granulocitos/efectos de los fármacos , Granulocitos/citología , Granulocitos/efectos de los fármacos , Granulocitos/efectos de la radiación , Leucopenia/prevención & control , Masculino , Meloxicam , Ratones , Ratones Endogámicos CBA , Irradiación Corporal TotalRESUMEN
Meloxicam, a selective inhibitor of cyclooxygenase 2, a nonsteroidal anti-inflammatory drug with an improved side-effects profile in terms of gastrointestinal toxicity, has been found to stimulate hematopoiesis in whole-body gamma-irradiated mice. A distinct corroboration of this positive action of meloxicam is an enhancement of the recovery of hematopoietic progenitor cells committed to granulocyte-macrophage and erythroid development, which has been demonstrated in sublethally irradiated animals treated with meloxicam at a dose of 20 mg/kg administered intraperitoneally either singly 1 h before irradiation or repeatedly after radiation exposure. The results suggest that meloxicam can be added to the list of biological response modifiers that can be used in the treatment of hematopoietic damage induced by ionizing radiation.
Asunto(s)
Médula Ósea/efectos de los fármacos , Médula Ósea/efectos de la radiación , Inhibidores de la Ciclooxigenasa 2/administración & dosificación , Rayos gamma/efectos adversos , Hematopoyesis/efectos de los fármacos , Hematopoyesis/efectos de la radiación , Protectores contra Radiación/administración & dosificación , Tiazinas/administración & dosificación , Tiazoles/administración & dosificación , Irradiación Corporal Total/efectos adversos , Animales , Médula Ósea/lesiones , Médula Ósea/patología , Células Cultivadas , Masculino , Meloxicam , Ratones , Dosis de RadiaciónRESUMEN
A single dose of IMUNOR, a low-molecular-weight immunodulator prepared from disintegrated and ultrafiltered pig leukocytes, was found to enhance recovery of murine pool of hemopoietic progenitor cells for granulocytes and macrophages damaged by a single injection of cytotoxic drugs 5-fluorouracil or cisplatin. The best results were obtained after the treatment with IMUNOR on days 3 or 4 after the injection of 5-fluorouracil or cisplatin. These results together with previous findings obtained in our laboratory suggest that IMUNOR has the potential to become a part of treatment schemes in oncological practice aimed at alleviation of myelosuppression evoked by cytotoxic anti-tumor therapy.
Asunto(s)
Antimetabolitos Antineoplásicos , Antineoplásicos , Enfermedades de la Médula Ósea/inducido químicamente , Enfermedades de la Médula Ósea/tratamiento farmacológico , Cisplatino , Fluorouracilo , Factores Inmunológicos/farmacología , Leucocitos/química , Leucocitos/inmunología , Animales , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/inmunología , Femenino , Granulocitos/efectos de los fármacos , Granulocitos/inmunología , Hematopoyesis/efectos de los fármacos , Factores Inmunológicos/química , Ratones , Ratones Endogámicos ICR , Células Madre/efectos de los fármacos , Porcinos , UltrafiltraciónRESUMEN
The aim of the studies was to ascertain if adenosine is able to co-operate with selected hematopoietic growth factors and cytokines, namely with granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), stem cell factor (SCF), interleukin-3 (IL-3), and interleukin-11 (IL-11), in inducing the growth of colonies from hematopoietic progenitor cells for granulocytes and macrophages (GM-CFC) from normal bone marrow cells in vitro. Adenosine was found not to produce any colonies when present in the cultures as the only potential stimulator. All the tested cytokines and growth factors were observed to induce the growth of distinct numbers of GM-CFC colonies, with the exception of IL-11. When suboptimal concentrations of the evaluated cytokines and growth factors were tested in the cultures in which various concentrations of adenosine were concomitantly present, mutually potentiating effects were found in the case of IL-3 and SCF. These results confirm the role of adenosine in regulation of granulopoiesis and predict IL-3 and SCF as candidates for further in vivo studies of their combined administration with adenosine.
Asunto(s)
Adenosina/farmacología , Proliferación Celular/efectos de los fármacos , Factores Estimulantes de Colonias/farmacología , Células Madre Hematopoyéticas/efectos de los fármacos , Interleucina-11/farmacología , Factor de Células Madre/farmacología , Animales , Células de la Médula Ósea/citología , Células de la Médula Ósea/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Factor Estimulante de Colonias de Granulocitos/farmacología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Granulocitos/citología , Granulocitos/efectos de los fármacos , Células Madre Hematopoyéticas/citología , Interleucina-3/farmacología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBARESUMEN
Combined administration of drugs elevating extracellular adenosine, namely dipyridamole and adenosine monophosphate, together with granulocyte colony-stimulating factor was shown to enhance granulopoietic recovery in the bone marrow of mice treated with 5-fluorouracil. Enhanced regeneration was found both at the level of hematopoietic progenitor cells for granulocytes and macrophages and in the compartment of morphologically recognizable granulocyte precursors. The results might have positive clinical impact. The adjunct use of drugs elevating extracellular adenosine might reduce the cost expenditure of therapy with granulocyte colony-stimulating factor.
Asunto(s)
Adenosina/metabolismo , Médula Ósea/efectos de los fármacos , Fluorouracilo/farmacología , Factor Estimulante de Colonias de Granulocitos/administración & dosificación , Granulocitos , Hematopoyesis/efectos de los fármacos , Adenosina Monofosfato/administración & dosificación , Animales , Células de la Médula Ósea , Dipiridamol/administración & dosificación , Interacciones Farmacológicas , Espacio Extracelular/metabolismo , Células Madre Hematopoyéticas/efectos de los fármacos , Humanos , Macrófagos , Masculino , Ratones , Proteínas Recombinantes/administración & dosificaciónRESUMEN
OBJECTIVE: Our previous studies showed that the combined administration of drugs elevating extracellular adenosine, i.e., dipyridamole and adenosine monophosphate (AMP), enhanced hematopoiesis in normal mice and increased hematopoietic recovery in irradiated mice. In the present study, we have examined the possibility that these effects are due to the adenosine-induced cycling of the hematopoietic progenitor cells. MATERIALS AND METHODS: Experiments were performed under in vivo conditions using B10CBAF1 mice. The cycling status of hematopoietic progenitor cells (CFU-S(day 10), CFC-GM, and BFU-E) was determined on the basis of their sensitivity to 5-fluorouracil (5-FU), a cycle-specific cytotoxic agent. RESULTS: Pretreatment of mice with dipyridamole + AMP enhanced the cytotoxic effects of a single bolus of 5-FU at a dose of 3 mg per mouse. Sensitizing effects of drugs occurred after a delay of several hours and attained a maximum of about 40-60% reduction of the progenitor cells surviving after 5-FU alone. The period of maximum sensitization of CFU-S by the combination of dipyridamole + AMP was shifted to later time intervals as compared with the effects on CFC-GM and BFU-E. Pretreatment of mice with the drugs also aggravated the 5-FU-induced lethality. Reduction of survival was found in mice exposed to two cycles of 3 mg of 5-FU following the pretreatment with dipyridamole + AMP at a time period characterized by the highest fraction of CFU-S in the S phase. CONCLUSIONS: The results suggest that adenosine receptor signaling, induced by the administration of drugs elevating extracellular adenosine, enhances cycling of the hematopoietic progenitor cells. These effects might have pharmacological implications in the therapy of blood disorders.
Asunto(s)
Adenosina Monofosfato/farmacología , Adenosina/metabolismo , Antimetabolitos Antineoplásicos/toxicidad , Dipiridamol/farmacología , Fluorouracilo/toxicidad , Células Madre Hematopoyéticas/efectos de los fármacos , Receptores Purinérgicos P1/efectos de los fármacos , Animales , Antimetabolitos Antineoplásicos/farmacología , Enfermedades de la Médula Ósea/inducido químicamente , Ciclo Celular/efectos de los fármacos , Ensayo de Unidades Formadoras de Colonias , Sinergismo Farmacológico , Espacio Extracelular/metabolismo , Fluorouracilo/farmacología , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Masculino , Ratones , Profármacos/farmacología , Receptores Purinérgicos P1/fisiologíaRESUMEN
The purpose of this study was to investigate effects of the treatment prior to irradiation with granulocyte colony-stimulating factor (G-CSF) on hematopoiesis in B10CBAF1 mice exposed to a sublethal dose of 6.5 Gy of 60Co gamma radiation. G-CSF was administered in a 4-day regimen (3 microg/day); irradiation followed 3 h after the last injection of G-CSF. Such a treatment was found to stimulate granulopoiesis, as shown by increased counts of granulocyte-macrophage progenitor cells (GM-CFC) and of granulocytic cells in the femoral marrow and spleen at the time of irradiation. However, postirradiation counts of GM-CFC and granulocytic cells in the marrow of mice pretreated with G-CSF were reduced up to day 18 after irradiation. Interestingly, the D0 values for marrow GM-CFC determined 1 h after in vivo irradiation were 1.98 Gy for controls and 2.47 Gy for mice pretreated with G-CSF, indicating a decreased radiosensitivity of these cells after drug treatment. The inhibitory effects of the pretreatment with G-CSF on the postirradiation granulopoiesis could be attributed to the phenomenon of "rebound quiescence" which can occur after cessation of the treatment with growth factors. Postirradiation recovery of erythropoiesis in the spleen of mice pretreated with G-CSF exhibited a dramatic increase and compensated for the decreased erythropoiesis in the marrow at the time of irradiation. This complexity of the hematopoietic response should be taken into account when administering G-CSF in preirradiation regimens.
Asunto(s)
Factor Estimulante de Colonias de Granulocitos/farmacología , Leucopoyesis/efectos de los fármacos , Leucopoyesis/efectos de la radiación , Animales , Médula Ósea/efectos de los fármacos , Médula Ósea/efectos de la radiación , Ensayo de Unidades Formadoras de Colonias , Filgrastim , Rayos gamma , Factor Estimulante de Colonias de Granulocitos/administración & dosificación , Granulocitos/citología , Granulocitos/efectos de los fármacos , Granulocitos/efectos de la radiación , Recuento de Leucocitos , Masculino , Ratones , Tolerancia a Radiación/efectos de los fármacos , Proteínas Recombinantes , Bazo/citología , Bazo/efectos de los fármacos , Bazo/efectos de la radiación , Factores de TiempoRESUMEN
Revascularization surgery in patients with peripheral arterial occlusive disease presents an acceptable clinical model for studying the rate of ischaemia-reperfusion injury of cells and other structures of skeletal muscle of the affected extremity. Validity of carefully chosen set of biochemical parameters for determination of this injury during and after surgery as well as in the early and late reperfusion periods and during the readaptation to situation after restoration of blood circulation was verified. Blood samples were taken from the regional common femoral vein which allowed to obtain information directly from the ischaemized extremity. Analyzed biochemical parameters have given useful information about the situation in acid-base regulation, in energy metabolism as well as antioxidant capacity. These parameters were estimated in four time intervals: before aorta cross-clamping (preischaemic phase), then 30 min (early reperfusion) and 18 hours (readaptation period) after aorta-declamping. In the early reperfusion period a marked acidosis and raised carbon dioxide tension, significant increase of lactate and pyruvate levels as well as increased hypoxanthine plasma level were observed. On the contrary, in this period the lowest lipoperoxide level was found, evident in the wake of relative stability of concentration of endogenous antioxidants documented by a constant glutathione redox status that at the first postoperative day even significantly decreased as a consequence of a drop of oxidized and increased of reduced form of glutathione. Therefore, the applied biochemical parameters allow to monitor the ischaemia-reperfusion damage of afflicted region and could be used even in the study of compounds with a protective effect against possible injury of ischaemized and reoxygenized tissues. (Tab. 3, Fig. 4, Ref. 32.)
Asunto(s)
Metabolismo Energético , Isquemia/cirugía , Daño por Reperfusión/metabolismo , Procedimientos Quirúrgicos Vasculares , Equilibrio Ácido-Base , Adulto , Antioxidantes/metabolismo , Femenino , Humanos , Isquemia/metabolismo , Ácido Láctico/sangre , Pierna/irrigación sanguínea , Masculino , Persona de Mediana Edad , Oxidación-Reducción , Ácido Pirúvico/sangreRESUMEN
The activation of adenosine receptors has recently been demonstrated to stimulate haematopoiesis. In the present study, we investigated the ability of drugs elevating extracellular adenosine to influence curative effects of granulocyte colony-stimulating factor (G-CSF) in mice exposed to a sublethal dose of 4 Gy of 60Co radiation. Elevation of extracellular adenosine in mice was induced by the combined administration of dipyridamole, a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), an adenosine prodrug. The effects of dipyridamole plus AMP, and G-CSF, administered either alone or in combination, were evaluated. The drugs were injected to mice in a 4-d treatment regimen starting on d 3 after irradiation and the haematopoietic response was evaluated on d 7, 10, 14, 18 and 24 after irradiation. While the effects of G-CSF on the late maturation stages of blood cells, appearing shortly after the completion of the treatment, were not influenced by dipyridamole plus AMP, positive effects of the combination therapy occurred in the post-irradiation recovery phase which is dependent on the repopulation of haematopoietic stem cells. This was indicated by the significant elevation of counts of granulocyte-macrophage progenitor cells (GM-CFC) and granulocytic cells in the bone marrow (d 14), of GM-CFC (d 14), granulocytic and erythroid cells (d 14 and 18) in the spleen, and of neutrophils (d 18), monocytes (d 14 and 18) and platelets (d 18) in the peripheral blood. These effects suggest that the repopulation potential of the combination therapy lies in a common multilineage cell population. The results of this study implicate the promising possibility to enhance the curative effects of G-CSF under conditions of myelosuppressive states induced by radiation exposure.
Asunto(s)
Adenosina Monofosfato/farmacología , Adenosina/metabolismo , Eritrocitos/efectos de los fármacos , Factor Estimulante de Colonias de Granulocitos/farmacología , Granulocitos/efectos de los fármacos , Células Madre Hematopoyéticas/efectos de los fármacos , Animales , Plaquetas/efectos de los fármacos , Dipiridamol/farmacología , Sinergismo Farmacológico , Femenino , Factor Estimulante de Colonias de Granulocitos y Macrófagos/efectos de los fármacos , Factor Estimulante de Colonias de Granulocitos y Macrófagos/efectos de la radiación , Granulocitos/efectos de la radiación , Células Madre Hematopoyéticas/efectos de la radiación , Linfocitos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos CBA , Monocitos/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/farmacología , Receptores Purinérgicos P1/metabolismoRESUMEN
The effects of diclofenac, an inhibitor of prostaglandin synthesis, were studied on the acute radiation syndrome elicited in mice by fractional irradiation. Several haematological parameters were evaluated in mice irradiated with 5x2 Gy and 3x, 4x, or 5x3 Gy (intervals between fractions 24 h) from a 60Co gamma-ray source. The animals were treated with diclofenac either before each fraction or only once before the last fraction. The survival of mice was recorded after the irradiation regimen of 5x3 Gy followed by a "top-up" dose of 3.5 Gy given 24 h after the last radiation fraction. Statistically significant enhancement of the endogenous spleen colony formation and of leukopoiesis was found in mice treated with diclofenac repeatedly, as compared with both saline-treated irradiated controls and animals administered a single diclofenac dose, if a sublethal total radiation dose had been accumulated. However, following accumulation of a lethal total radiation dose, slightly impaired survival was observed in mice given diclofenac. It follows from the results that diclofenac is a suitable drug for enhancing leukopoiesis impaired by sublethal fractionated irradiation. Nevertheless, undesirable side effects of this drug negatively influence the survival of experimental animals following a lethal accumulated radiation dose.
Asunto(s)
Diclofenaco/farmacología , Hematopoyesis/efectos de los fármacos , Traumatismos Experimentales por Radiación/sangre , Animales , Supervivencia Celular/efectos de la radiación , Ensayo de Unidades Formadoras de Colonias , Recuento de Eritrocitos/efectos de los fármacos , Recuento de Eritrocitos/efectos de la radiación , Rayos gamma , Hematopoyesis/efectos de la radiación , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Hematopoyéticas/efectos de la radiación , Recuento de Leucocitos/efectos de los fármacos , Recuento de Leucocitos/efectos de la radiación , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Irradiación Corporal TotalRESUMEN
Experimental evidence suggests that the activation of purinoceptors by extracellular adenosine can modulate proliferation and/or differentiation of hematopoietic cells. The present study was undertaken to investigate the potential interactions of this system of intercellular signaling with the effects of granulocyte colony-stimulating factor (G-CSF) on granulopoiesis in vivo. Elevation of extracellular adenosine in normal mice was induced by the joined administration of dipyridamole, a drug inhibiting the cellular uptake of adenosine, and adenosine monophosphate (AMP), an adenosine prodrug. The effects of dipyridamole, AMP, and G-CSF, administered either alone or in combinations, were evaluated. The agents were injected to mice in a 4-day regimen, and the hematologic endpoints were determined 24 hours after the completion of the treatment. It was shown that the effects of G-CSF, ie, increases in peripheral blood neutrophils, granulocyte-macrophage progenitor cells (GM-CFC), and morphologically determined granulocytic cells in femoral marrow and a decrease in the marrow erythroid cells, can be enhanced by the combination of dipyridamole plus AMP administered 30 minutes before G-CSF. Furthermore, it was ascertained that the stimulatory action of dipyridamole plus AMP was expressed particularly at lower doses of G-CSF (1.5, 3, and 4.5 micrograms/d). At higher doses of G-CSF (6 and 9 micrograms/d), the interactions were no more evident. When combining dipyridamole, AMP, and 3 micrograms of G-CSF, peripheral neutrophils increased approximately 3.9- to 4.5-fold compared with an approximate 2.2-fold increase induced by G-CSF alone. The results indicate the possible therapeutic potential of combination therapy with G-CSF and drugs increasing extracellular adenosine.
Asunto(s)
Adenosina Monofosfato/farmacología , Adenosina/biosíntesis , Dipiridamol/farmacología , Espacio Extracelular/metabolismo , Factor Estimulante de Colonias de Granulocitos/farmacología , Hematopoyesis/efectos de los fármacos , Células Madre Hematopoyéticas/efectos de los fármacos , Neutrófilos/citología , Animales , Diferenciación Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Sinergismo Farmacológico , Filgrastim , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Proteínas Recombinantes/farmacologíaRESUMEN
The purpose of the studies reported here was to investigate the ability of the combined administration of dipyridamole and adenosine monophosphate, drugs known to elevate extracellular adenosine, to protect mice undergoing treatment with fractionated irradiation (five doses of 2 or 3 Gy each) given at 24-h intervals. Based on observations of hemopoietic recovery (endogenous hemopoietic spleen colony formation, marrow granulocyte-macrophage colony-forming cells, peripheral blood cells) after the completion of fractionated irradiation and on survival studies, it was demonstrated that the repeated administration of the drugs 60 min before each of the radiation fractions mitigates the hemopoietic injury and enhances the survival of mice irradiated with an additional "top-up" dose. It could be deduced that the single protective actions of the drugs retain their efficacy in repeated treatment and enhance the sparing effect of dose fractionation on hemopoiesis. Interestingly, the toxic side effects of the drugs tend to decrease when they are administered repeatedly, probably due to the development of tolerance to their cardiovascular action. This reduction in toxicity offers benefit with respect to the potential use of these hemopoiesis-protecting drugs in clinical radiotherapy.
Asunto(s)
Adenosina Monofosfato/farmacología , Dipiridamol/farmacología , Hematopoyesis/efectos de la radiación , Protectores contra Radiación/farmacología , Adenosina Monofosfato/toxicidad , Animales , Dipiridamol/toxicidad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos CBA , Bazo/efectos de la radiación , Tasa de SupervivenciaRESUMEN
The hemopoiesis-enhancing ability of a soluble glucan derivative, i.e. carboxymethylglucan (CMG), was investigated in gamma-irradiated mice. Attention was focused on the usefulness of its single or repeated postirradiation administration. CMG was administered i.p. at (a) single dose of 6 mg 2 h postirradiation, (b) four 6 mg doses in the first 4 days postirradiation, (c) four 1.5 mg doses at the same time intervals. Indices of granulopoiesis and inflammatory side effects (liver weight increase and hepatic granulomas) were investigated in mice irradiated with a sublethal dose of 7 Gy. All three CMG-treated groups of mice were found to exhibit enhanced hemopoietic recovery in comparison with the controls. Although the mice repeatedly given the 6 mg CMG doses showed the most rapid recoveries of all the evaluated parameters of granulopoiesis, the most pronounced hepatic side effects were found in these mice, too. When survival of mice was recorded in lethally (9 Gy) irradiated animals, the best protective response were obtained following the repeated administration of the 1.5 mg CMG dose, the survival by day 30 in this group being significantly higher not only in comparison with the controls but also with the mice repeatedly given the 6 mg dose of CMG. The results suggest that the postirradiation CMG administration can be useful for enhancing radiation suppressed hemopoiesis. However, repeated larger CMG doses may produce side effects which compromise the overall survival of irradiated mice.
Asunto(s)
Glucanos/farmacología , Hematopoyesis/efectos de los fármacos , Traumatismos Experimentales por Radiación/terapia , beta-Glucanos , Animales , Médula Ósea/efectos de los fármacos , Endotoxinas/toxicidad , Glucanos/efectos adversos , Hígado/efectos de los fármacos , Masculino , Ratones , Traumatismos Experimentales por Radiación/patología , Células Madre/efectos de los fármacosRESUMEN
Carboxymethylglucan (CMG), a water-soluble glucan derivative, enhanced the number of granulocytes in the peripheral blood as well as other indices of haemopoietic recovery (total cellularity and the number of granulocyte-macrophage progenitor cells in femoral marrow, spleen weight) investigated after fractionated gamma-irradiation in mice (five doses of 2 Gy each, or three, four and five doses of 3 Gy each given at 24-h intervals). An increased liver weight and a more pronounced anaemia found in the CMG-treated mice suggested, however, that also inflammatory side effects were evoked by the repeated administration of CMG. On the other hand, the development of tolerance, i.e., a decreased effectiveness of the treatment with CMG upon its repeated administration, did not seem to play any major role under the experimental conditions studied, because the protective effects of CMG increased with the increasing number of CMG injections.
Asunto(s)
Glucanos/administración & dosificación , Hematopoyesis/efectos de los fármacos , Adyuvantes Inmunológicos/administración & dosificación , Animales , Hematopoyesis/efectos de la radiación , Masculino , Ratones , Irradiación Corporal TotalRESUMEN
We have recently demonstrated that the combined administration of dipyridamole and adenosine monophospate to mice induces radioprotective effects in terms of postirradiation haemopoietic recovery in animals irradiated with a single dose. The aim of the present experiments was to investigate the radioprotective ability of the drug combination under conditions of fractionated radiation treatment. It has been shown that administration of drugs either 15 or 60 min before each of the five daily 3-Gy doses of gamma-radiation enhances haemopoietic recovery and survival of mice exposed to an additional "top-up" dose of 3.5 Gy. Furthermore, it has been ascertained that the regimen using administration of the drugs 60 min prior to irradiation is more effective than administration of the drugs 15 min prior to irradiation. Due to the evidence that administration of the drugs 15 min prior to irradiation protects the organism mainly via mechanisms of systemic hypoxia while the pretreatment 60 min before irradiation avoids the role of hypoxia and mainly induces cell proliferation effects, our results suggest a more effective protective role of mechanisms stimulating haemopoiesis under conditions of fractionated radiation. The data may provide a basis for more rational use of radioprotection in fractionated radiation regimens.
Asunto(s)
Adenosina Monofosfato/farmacología , Dipiridamol/farmacología , Protectores contra Radiación/farmacología , Vasodilatadores/farmacología , Animales , Peso Corporal , División Celular/efectos de los fármacos , División Celular/efectos de la radiación , Esquema de Medicación , Quimioterapia Combinada , Sistema Hematopoyético/citología , Sistema Hematopoyético/efectos de los fármacos , Sistema Hematopoyético/efectos de la radiación , Hipoxia/tratamiento farmacológico , Hipoxia/fisiopatología , Masculino , Ratones , Ratones Endogámicos C57BL , Tamaño de los Órganos , Análisis de Supervivencia , Factores de TiempoRESUMEN
Two non-steroidal anti-inflammatory drugs, i.e. indomethacin (INDO), an inhibitor of prostaglandin production, and esculetin (ESCUL), an inhibitor of leukotriene production, were tested for their ability to modify haematopoiesis in three experimental systems: (a) in vitro clonal proliferation of marrow GM-CFC from the irradiated mouse was found to be augmented by addition of INDO at a low concentration, and inhibited by ESCUL in a dose-dependent manner; (b) in the lethally irradiated and bone marrow-transplanted mice treated with the drugs in the postirradiation period, stimulatory effects of INDO on CFU-S and GM-CFC populations and an inhibitory effect of ESCUL on GM-CFC were observed; and (c) when the drugs were administered i.p. to mice 1 h before 5-Gy irradiation, INDO enhanced the postirradiation recovery of haematopoietic indices such the numbers of CFU-S, GM-CFC, peripheral blood granulocytes, and nucleated bone marrow cells, while ESCUL had no effect or even inhibited the recovery of these indices. Survival curves for CFU-S and GM-CFC showed that altered haematopoietic recovery in the INDO- and ESCUL-pretreated mice was not due to changes of intrinsic radiosensitivity of pluripotent (CFU-S) or committed (GM-CFC) stem cell populations. These results confirm earlier findings suggesting an inhibitory role of prostaglandins on haematopoiesis, and provide evidence that endogenous leukotrienes might play a positive role in the regulation of haematopoietic functions in an irradiated organism.