The combined administration of daniplestim and Mpl ligand augments the hematopoietic reconstitution observed with single cytokine administration in a nonhuman primate model of myelosuppression

Danggui sini decoction ameliorates myelosuppression in animal model by upregulating Thrombopoietin expression

Danggui Sini decoction (DSD), a famous Chinese medicine, has been used therapeutically in various diseases. In this study, we tried to investigate whether and how DSD could ameliorate myelosuppression in an animal model, in which myelosuppression is induced by cyclophosphamide treatment. The myelosuppression model was established by intraperitoneal injection of 100 mg/kg cyclophosphamide in mice. Flow cytometry was used to assess cell numbers and evaluate the bone marrow cell cycle distribution. Spleen samples were collected, and the mRNA expression levels of thrombopoietin (TPO) and c-Mpl were analyzed by RT-PCR. Our results demonstrated that DSD could significantly elevate the level of bone marrow hematopoietic stem progenitor cells in myelosuppression mice model. DSD also accelerated cell proliferation by switching cell cycles from G0/G1 phase to S and G2/M phase. Moreover, DSD significantly elevated the mRNA expression level of TPO, but not c-Mpl in spleen. Overall, the present results indicated that DSD is a promising Chinese medicine that is highly potent to ameliorate myelosuppression induced by chemotherapy by upregulating TPO expression.

Role of cytokines and growth factors in radioprotection

Cytokines and growth factors are growing groups of proteins that are responsible for the communication between cells of the immune system, hematopoietic cells, and other cell types. The cloning and large-scale production in a recombinant form of these agents in pharmacological quantities permitted investigations aimed at assessing the benefit they may provide in preserving and restoring functions of tissues compromised by irradiation. We have extensively examined past investigations which suggest that some cytokines and growth factors protect animals from radiation lethality when given prior to or after irradiation, and even in untreated animals, these cytokines serve in innate defenses against external stimuli. In contrast, some cytokines given before irradiation sensitize the animals to radiation lethality. Unfortunately, due to their adverse side effects, these cytokines were not found suitable as radioprotectors. Recent studies suggest that new approaches may bring cytokines and growth factors in clinic for radiation injury. The information and insight gained about therapeutic potential of cytokine manipulation will allow for more rational design of treatment protocols.

Hematopoietic recovery following autologous bone marrow transplantation in a nonhuman primate: effect of variation in treatment schedule with PEG-rHuMGDF

Mathematical modeling of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) pharmacokinetics (PK) and pharmacodynamics (PD) suggest that variations in the PEG-rHuMGDF treatment schedule could reduce the severity and duration of thrombocytopenia following myeloablation and bone marrow transplant (BMT). We tested this hypothesis in a rhesus monkey model of autologous (Au) bone marrow-derived mononuclear cell (BM-MNC) transplantation following lethal myeloablation. On day 0, animals were myeloablated by total body exposure to 920 cGy, 250 kVp x-irradiation (TBI). Four cohorts of animals were infused with 1 x 10(8) AuBM-MNC/kg body weight within 2 hours of TBI. The AuBMT-alone cohort received no cytokine, the daily dosage cohort received PEG-rHuMGDF (2.5 micro g/kg/day, s.c.) post TBI and AuBMT, and the pre/post-transplant cohort received PEG-rHuMGDF (2.5 micro g/kg/day, s.c.) pre (day -9 to day -5) and post TBI and AuBMT. The post-transplant PEG-rHuMGDF administration in the above cohorts was begun on day 1 post TBI and continued until platelet counts reached 200,000 micro l (range, 15-31 days). Another group received PEG-rHuMGDF (300 micro g/kg/day, s.c.) on days 1 and 3 only following TBI and AuBMT. The TBI controls received neither AuBMT nor cytokine therapy. In this model of AuBMT, with regard to the PEG-rHuMGDF administration schedule, the daily dosage of the post-transplant cohort did not significantly improve platelet recovery; the pre/post-transplant schedule and an abbreviated high-dosage, post-transplant schedule (days 1 and 3) significantly improved the duration and nadir of thrombocytopenia and platelet recovery. These data confirm predictions from PK/PD modeling of PEG-rHuMGDF that thrombocytopenia is preventable following AuBMT.

Early dose assessment in criticality accidents

Early estimation of dose is useful in the medical evaluation of severe radiation accidents. In a prior publication, lymphocyte depletion kinetics were shown to follow an exponential decline for gamma accidents in which the average whole-body dose was in the range 50 cGy < D < 8-10 Gy. In that study, the depletion rate constant was linearly related to dose, within the statistical variation of the historical hematological data. This simple technique has now been extended to include analysis of various types of criticality accidents (liquid process; water moderated systems; metallic systems). Lymphocyte depletion in high-level mixed gamma/neutron accidents is found to be approximately equal, at a given effective dose, to that for gamma accidents. This universality would indicate a neutron RBE for human lymphocytes close to unity. Furthermore, the technique appears to be insensitive to the shape of gamma and neutron spectra, therefore making it especially robust for initial, approximate dose estimation.