5-androstenediol stimulates multilineage hematopoiesis in rhesus monkeys with radiation-induced myelosuppression
ABSTRACT Total body ionizing irradiation (TBI) between 2-8 Gy causes the hematopoietic component of the acute radiation syndrome (ARS) in humans. Here we report on an exploratory study with 5-androstenediol (AED) in rhesus monkeys exposed to 4 Gy (60)Co gamma TBI. In this study, the effects of two formulations administered 3-4 h after irradiation were evaluated. After radiation, severe neutropenia (<500 neutrophils/microL), thrombocytopenia (<50,000 platelets/microL), and anemia (hemoglobin <8.0 g/dL) occurred in 6, 6, and 5 of the 6 control animals, respectively. In these 6 control animals, the median time to first day of each defined cytopenia was 8.5, 13, and 20 days and the median time to last occurrence was 22.5, 19.5 and 29.5 days, respectively. All treated groups had a decrease in the duration of severe neutropenia relative to vehicle control. All but one dosing regimen decreased the duration of thrombocytopenia and anemia. Five consecutive days of a 15 mg/kg intramuscular (IM) micro-particle preparation and a once weekly 15 mg/kg subcutaneous (SC) nanoparticle suspension generally provided the greatest radiation protection. AED, as a single agent, promotes multilineage hematopoietic recovery of the bone marrow. These data suggest that it may play an important therapeutic role in the management of acute radiation syndrome.
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ABSTRACT: The development of an effective pharmacological countermeasure is needed to reduce the morbidity and mortality in military and civilian populations associated with possible exposure to ionizing radiation. Previous studies in mice have shown that a single subcutaneous (sc) injection of the natural steroid androst-5-ene-3beta,17beta-diol (5-androstenediol, 5-AED), 24-48 h prior to a lethal dose of whole-body (60)Co gamma radiation, stimulated hematopoiesis and enhanced survival. These effects are consistent with our previous observation of 5-AED-induced elevations in circulating G-CSF in normal and irradiated mice. The purpose of this study was to obtain data on the pharmacokinetics of 5-AED after sc and buccal administration to mice, and to determine whether cytokine genes are induced by sc 5-AED in hematopoietic tissues (bone marrow, spleen). We studied effects on serum cytokines and chemokines, and also analyzed the pharmacokinetics of 5-AED after sc administration and compared it with buccal delivery. 5-AED was administered 24 h before irradiation or sham-irradiation. Cytokine mRNAs were quantified by quantitative real-time PCR (QRT-PCR), and cytokine levels in serum by multiplex Luminex. 5-AED administration was associated with elevation of message for GM-CSF, IL-2, IL-3, IL-6, and IL-10 in spleen, and GM-CSF and IL-2 in bone marrow. Irradiation enhanced G-CSF, GM-CSF, IFN-gamma, TPO, IL-2, IL-3, IL-6, IL-10, and IL-12 in spleen, and GM-CSF, IFN-gamma, TPO, IL-3, and IL-10 in bone marrow. Serum levels of G-CSF were significantly elevated in 5-AED-treated mice 4 h after irradiation or sham-irradiation. Serum macrophage inflammatory protein-1gamma (MIP-1gamma) was significantly elevated 4 h after irradiation in 5-AED-treated mice. Plasma 5-AED peaked 2 h after sc injection (30 mg/kg), and remained significantly above control after 4 days, but not 8 days. The time course of plasma 5-AED after buccal delivery (60 mg/kg) was similar, but levels were significantly lower compared to sc delivery. Plasma 5-AED 24 h after administration was not significantly different between sc and buccal delivery. However, in contrast to many studies showing enhanced survival after sc administration of 5-AED, we found no effect on survival of buccal 5-AED. The results suggest that radioprotection is not dependent on the 5-AED concentration at the time of irradiation, but rather on events triggered during the first few hours after administration. The current results suggest that further studies are warranted to directly test the roles of cytokines in the radioprotective effects of 5-AED.Experimental and Molecular Pathology 05/2008; 84(2):178-88. DOI:10.1016/j.yexmp.2007.12.001 · 2.88 Impact Factor
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ABSTRACT: We previously reported that five daily intramuscular doses of 5-androstenediol (AED), a naturally occurring adrenal steroid hormone, stimulated multilineage recovery of bone marrow in rhesus monkeys with radiation-induced myelosuppression after 4.0 Gy total body irradiation (TBI). Here we report the effect of AED on the survival of eighty rhesus macaques that received a 6.0 Gy dose of TBI in four sequential pilot studies. The drug was administered intramuscularly, based on body weight, 2-4 h after irradiation and continued once daily for a total of five injections. No clinical support in the form of antibiotics or transfusions was given to the animals at any time during the study. Five of the 40 (12.5%) treated animals died, compared to 13 of 40 (32.5%) of the animals in the control group (p=0.032). The combination of accumulated days of thrombocytopenia (<20,000 platelets/microL) up to day 14 (before the first death) together with treatment, accurately predicts mortality (p<0.001). The compound significantly reduced the duration of thrombocytopenia and neutropenia (p<0.01). The accumulation of days of neutropenia (ANC<500 cells/microL) up to day 14 plays no major role in predicting death. AED shows significant activity in irradiated primates with acute hematopoietic radiation syndrome.International Immunopharmacology 05/2007; 7(4):500-5. DOI:10.1016/j.intimp.2006.12.005 · 2.71 Impact Factor
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ABSTRACT: 5-Androstenediol (5-AED) stimulates hematopoiesis and enhances survival in animals exposed to ionizing radiation (IR), suggesting that this steroid may act on hematopoietic progenitor cells. We used gamma-irradiated primary human CD34(+) hematopoietic progenitor cells to show that 5-AED protects hematopoietic cells from IR damage, as shown by enhanced cell survival, clonogenicity, proliferation, and differentiation. Unlike in tumor cells, IR did not induce nuclear factor-kappaB (NFkappaB) activation in primary progenitors. However, IR stimulated IkappaB(beta) release from NFkappaB/IkappaB complexes and caused NFkappaB1 (p50) degradation. 5-AED stabilized NFkappaB1 in irradiated cells and induced NFkappaB gene expression and NFkappaB activation (DNA binding). 5-AED stimulated interleukin-6 and granulocyte colony-stimulating factor (G-CSF) secretion. The survival-enhancing effects of 5-AED on clonogenic cells were abrogated by small interfering RNA inhibition of NFkappaB gene expression and by neutralization of G-CSF with antibody. The effects of 5-AED on survival and G-CSF secretion were blocked by the NFkappaB inhibitor N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal (MG132). 5-AED had no effect on accumulation of the proapoptotic factor p53 after IR, as determined by Western blot. The results indicate that NFkappaB1 degradation after IR may be responsible for the radiation sensitivity of CD34+ cells compared with tumor cells. 5-AED exerts survival-enhancing effects on irradiated human hematopoietic progenitor cells via induction, stabilization, and activation of NFkappaB, which results in increased secretion of hematopoietic growth factor G-CSF.Molecular Pharmacology 09/2007; 72(2):370-9. DOI:10.1124/mol.107.035394 · 4.12 Impact Factor