Prediction of Survival Benefit of Filgrastim in Adult and Pediatric Patients With Acute Radiation Syndrome.

Acute exposure to high doses of radiation leads to severe myelosuppression, but few treatments are currently available to treat hematopoietic syndrome of acute radiation syndrome. Granulocyte colony stimulating factors (e.g., filgrastim) stimulate proliferation of neutrophil precursors and enhance mature neutrophil function. Owing to ethical constraints on conducting clinical research in lethally irradiated humans, we developed a model-based strategy to integrate preclinical experience in irradiated nonhuman primates (NHPs) and other clinical myelosuppressive conditions to inform filgrastim dosing to treat hematopoietic syndrome of acute radiation syndrome. Models predicting neutrophil counts and overall survival based on drug exposures were calibrated and scaled from NHPs to adult and pediatric human subjects. Several scenarios were examined investigating variations in filgrastim doses, dose frequency, treatment initiation, and duration, as well as the effect of age and radiation dose rate. Model-based simulations and established safety profiles supported that a subcutaneous filgrastim dose of 10 µg/kg once daily provides a significant survival benefit (50%) over placebo in both adults and children, provided that the treatment is initiated within 1-14 days after radiation exposure and lasts 2-3 weeks. For treatment durations of longer than 3 weeks, filgrastim treatment is not expected to provide significantly greater benefit. This survival benefit is expected to hold for the wide range of radiation doses and dose rates (0.01-1,000 Gy/hours) examined.

Study of the Effects and Mechanisms of Ginsenoside Compound K on Myelosuppression.

Ginsenoside compound K (CK) is not a ginsenoside that naturally exists in Panax ginseng Meyer. However, CK is a major metabolite of ginsenoside Rb1, Rb2, or Rc in the intestine under the effects of bacteria. In this study, we first investigated the effects of CK on myelosuppression in mice induced by cyclophosphamide (CTX). The respective quantities of white blood cells, blood platelets, and bone marrow nucleated cells (BMNCs) were determined to be 8.54 ± 0.91 (109/L), 850.90 ± 44.11 (109/L), and 1.45 ± 0.22 (109/L) in the CK-H group by detecting peripheral blood cells and BMNCs. CK-H and CK-L both increased the thymus index by up to 0.62 ± 0.06 (mg/g) and 0.52 ± 0.09 (mg/g), respectively, and significantly increased the yields of colony formation units-granulocyte monocyte and colony formation units-megakaryocytic. According to our study, CK could control apoptosis and promote cells to enter the normal cell cycle by the bcl-2/bax signaling pathway and MEK/ERK signaling pathway. Therefore, the BMNCs could proliferate and differentiate normally after entering the normal cell cycle. So the peripheral blood cells could show a trend of returning to normal. The recovery of peripheral blood cells resulting in the level of cytokines tended to normal. This process may be the mechanisms of CK on myelosuppression. This study provides a reference for ginseng in the treatment of myelosuppression.

Design and synthesis of coumarin-based organoselenium as a new hit for myeloprotection and synergistic therapeutic efficacy in adjuvant therapy.

A newly designed organoselenium compound, methyl substituted umbelliferone selenocyanate (MUS), was synthesized as a primary hit against the myelotoxic activity of carboplatin. MUS was administered at 6 mg/kg b.wt, p.o. in concomitant and pretreatment schedules with carboplatin (12 mg/kg b.wt, i.p. for 10 days) in female Swiss albino mouse. MUS treatment reduced (P < 0.001) the percentage of chromosomal aberrations, micronuclei formation, DNA damage and apoptosis in murine bone marrow cells and also enhanced (P < 0.001) the bone marrow cell proliferation of the carboplatin-treated mice. These activities cumulatively restored the viable bone marrow cell count towards normalcy. Myeloprotection by MUS was achieved, in part, due to a significant reduction in the ROS/RNS formation and restoration of glutathione redox pool. Additionally, MUS synergistically enhanced the cytotoxicity of carboplatin against two human cancer cell lines (MCF-7 and Colo-205). Furthermore, MUS can effectively potentiate the antitumour activity of carboplatin against two murine cancers (Dalton's Lymphoma and Sarcoma-180) in vivo. These preclinical findings clearly indicate that MUS can improve the therapeutic index of carboplatin and ensures more effective therapeutic strategy against cancer for clinical development.

Pan-mutant-IDH1 inhibitor BAY1436032 is highly effective against human IDH1 mutant acute myeloid leukemia in vivo.

Neomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are frequently found in several human cancer types including acute myeloid leukemia (AML) and lead to the production of high levels of the oncometabolite (R)-2-hydroxyglutarate (R-2HG). Here we report the characterization of BAY1436032, a novel pan-mutant IDH1 inhibitor, both in vitro and in vivo. BAY1436032 specifically inhibits R-2HG production and colony growth, and induces myeloid differentiation of AML cells carrying IDH1R132H, IDH1R132C, IDH1R132G, IDH1R132L and IDH1R132S mutations. In addition, the compound impacts on DNA methylation and attenuates histone hypermethylation. Oral administration of BAY1436032 led to leukemic blast clearance, myeloid differentiation, depletion of leukemic stem cells and prolonged survival in two independent patient-derived xenograft IDH1 mutant AML mouse models. Together, BAY1436032 is highly effective against all major types of IDH1 mutant AML.

The anti-tumor effect of the quinoline-3-carboxamide tasquinimod: blockade of recruitment of CD11b(+) Ly6C(hi) cells to tumor tissue reduces tumor growth.

BACKGROUND: Previous work has demonstrated immunomodulatory, anti-tumor, anti-metastatic and anti-angiogenic effects of the small molecule quinoline-3-carboxamide tasquinimod in pre-clinical cancer models. To better understand the anti-tumor effects of tasquinimod in transplantable tumor models, we have evaluated the impact of the compound both on recruitment of myeloid cells to tumor tissue and on tumor-induced myeloid cell expansion as these cells are known to promote tumor development. METHODS: Mice bearing subcutaneous 4 T1 mammary carcinoma tumors were treated with tasquinimod in the drinking water. A BrdU-based flow cytometry assay was utilized to assess the impact of short-term tasquinimod treatment on myeloid cell recruitment to tumors. Additionally, long-term treatment was performed to study the anti-tumor effect of tasquinimod as well as its effects on splenic myeloid cells and their progenitors. Myeloid cell populations were also immune-depleted by in vivo antibody treatment. RESULTS: Short-term tasquinimod treatment did not influence the proliferation of splenic Ly6C(hi) and Ly6G(hi) cells, but instead reduced the influx of Ly6C(hi) cells to the tumor. Treatment with tasquinimod for various periods of time after tumor inoculation revealed that the anti-tumor effect of this compound mainly operated during the first few days of tumor growth. Similar to tasquinimod treatment, antibody-mediated depletion of Ly6C(hi) cells within that same time frame, caused reduced tumor growth, thereby confirming a significant role for these cells in tumor development. Additionally, long-term tasquinimod treatment reduced the splenomegaly and expansion of splenic myeloid cells during a later phase of tumor development. In this phase, tasquinimod normalized the tumor-induced alterations in myeloerythroid progenitor cells in the spleen but had only limited impact on the same populations in the bone marrow. CONCLUSIONS: Our results indicate that tasquinimod treatment reduces tumor growth by operating early after tumor inoculation and that this effect is at least partially caused by reduced recruitment of Ly6C(hi) cells to tumor tissue. Long-term treatment also reduces the number of splenic myeloid cells and myeloerythroid progenitors, but these effects did not influence established rapidly growing tumors.

Atheroprotection through SYK inhibition fails in established disease when local macrophage proliferation dominates lesion progression.

Macrophages in the arterial intima sustain chronic inflammation during atherogenesis. Under hypercholesterolemic conditions murine Ly6C(high) monocytes surge in the blood and spleen, infiltrate nascent atherosclerotic plaques, and differentiate into macrophages that proliferate locally as disease progresses. Spleen tyrosine kinase (SYK) may participate in downstream signaling of various receptors that mediate these processes. We tested the effect of the SYK inhibitor fostamatinib on hypercholesterolemia-associated myelopoiesis and plaque formation in Apoe(-/-) mice during early and established atherosclerosis. Mice consuming a high cholesterol diet supplemented with fostamatinib for 8 weeks developed less atherosclerosis. Histologic and flow cytometric analysis of aortic tissue showed that fostamatinib reduced the content of Ly6C(high) monocytes and macrophages. SYK inhibition limited Ly6C(high) monocytosis through interference with GM-CSF/IL-3 stimulated myelopoiesis, attenuated cell adhesion to the intimal surface, and blocked M-CSF stimulated monocyte to macrophage differentiation. In Apoe(-/-) mice with established atherosclerosis, however, fostamatinib treatment did not limit macrophage accumulation or lesion progression despite a significant reduction in blood monocyte counts, as lesional macrophages continued to proliferate. Thus, inhibition of hypercholesterolemia-associated monocytosis, monocyte infiltration, and differentiation by SYK antagonism attenuates early atherogenesis but not established disease when local macrophage proliferation dominates lesion progression.

Rosiglitazone Promotes Bone Marrow Adipogenesis to Impair Myelopoiesis under Stress.

OBJECTIVE: The therapeutic use of thiazolidinediones (TZDs) causes unwanted hematological side effects, although the underlying mechanisms of these effects are poorly understood. This study tests the hypothesis that rosiglitazone impairs the maintenance and differentiation of hematopoietic stem/progenitor cells, which ultimately leads to hematological abnormalities. METHODS: Mice were fed a rosiglitazone-supplemented diet or a normal diet for 6 weeks. To induce hematopoietic stress, all mice were injected once with 250 mg/kg 5-fluorouracil (5-Fu) intraperitoneally. Next, hematopoietic recovery, hematopoietic stem/progenitor cells (HSPCs) subsets, and myeloid differentiation after 5-Fu treatment were evaluated. The adipogenesis induced by rosiglitazone was assessed by histopathology and oil red O staining. The effect of adipocytes on HSPCs was studied with an in vitro co-culture system. RESULTS: Rosiglitazone significantly enhanced bone marrow adipogenesis and delayed hematopoietic recovery after 5-Fu treatment. Moreover, rosiglitazone inhibited proliferation of a granulocyte/monocyte progenitor (GMP) cell population and granulocyte/macrophage colony-stimulating factor (GM-CSF) colonies, although the proliferation and mobilization of Lin-c-kit+Sca-1+ cells (LSK) was maintained following hematopoietic stress. These effects could be partially reversed by the selective PPARγ antagonist BADGE. Finally, we demonstrated in a co-culture system that differentiated adipocytes actively suppressed the myeloid differentiation of HSPCs. CONCLUSION: Taken together, our results demonstrate that rosiglitazone inhibits myeloid differentiation of HSPCs after stress partially by inducing bone marrow adipogenesis. Targeting the bone marrow microenvironment might be one mechanism by which rosiglitazone impairs stress-induced hematopoiesis.

Preclinical Characterization of G1T28: A Novel CDK4/6 Inhibitor for Reduction of Chemotherapy-Induced Myelosuppression.

Chemotherapy-induced myelosuppression continues to represent the major dose-limiting toxicity of cytotoxic chemotherapy, which can be manifested as neutropenia, lymphopenia, anemia, and thrombocytopenia. As such, myelosuppression is the source of many of the adverse side effects of cancer treatment including infection, sepsis, bleeding, and fatigue, thus resulting in the need for hospitalizations, hematopoietic growth factor support, and transfusions (red blood cells and/or platelets). Moreover, clinical concerns raised by myelosuppression commonly lead to chemotherapy dose reductions, therefore limiting therapeutic dose intensity, and reducing the antitumor effectiveness of the treatment. Currently, the only course of treatment for myelosuppression is growth factor support which is suboptimal. These treatments are lineage specific, do not protect the bone marrow from the chemotherapy-inducing cytotoxic effects, and the safety and toxicity of each agent is extremely specific. Here, we describe the preclinical development of G1T28, a novel potent and selective CDK4/6 inhibitor that transiently and reversibly regulates the proliferation of murine and canine bone marrow hematopoietic stem and progenitor cells and provides multilineage protection from the hematologic toxicity of chemotherapy. Furthermore, G1T28 does not decrease the efficacy of cytotoxic chemotherapy on RB1-deficient tumors. G1T28 is currently in clinical development for the reduction of chemotherapy-induced myelosuppression in first- and second-line treatment of small-cell lung cancer. Mol Cancer Ther; 15(5); 783-93. ©2016 AACR.

Radiation-induced hematopoietic myelosuppression and genotoxicity get significantly countered by active principles of Podophyllum hexandrum: A study in strain 'A' mice.

PURPOSE: To investigate the protective role of a novel formulation, prepared by a combination of three active principles isolated from Podophyllum hexandrum (G-002M), against radiation- mediated hematopoietic suppression and cytogenetic aberrations in lethally irradiated mice. MATERIALS AND METHODS: G-002M, a combination of podophyllotoxin, podophyllotoxin-ß-D glucoside and rutin, was administered intramuscularly in mice (- 1 h) to radiation (9 Gy) exposure. The animals were autopsied at different time intervals for further studies. RESULTS: Loss of bone marrow progenitor cells, altered myeloid/erythroid ratio, serum erythropoietin and pancytopenia in irradiated mice was found significantly (p < 0.001) ameliorated in G-002M pre-administered mice within 30 d. Bcl-2 (B-cell lymphoma 2) and BAX (Bcl-2-associated X) protein expression was also positively (p < 0.001) countered in these mice. Chromosomal aberrations in 30 d were found remarkably (p < 0.001) reduced in marrow of G-002M pretreated mice. Accelerated antioxidants, reduced DNA damage, stimulated lymphocyte proliferation and minimal cellular atrophy in spleen were some of the other key features observed in G-002M administered mice. CONCLUSIONS: Reduction in hematopoietic aplasia and chromosomal aberrations, besides, early recovery in bone marrow and spleen of G-002M pretreated mice, could be attributed to its free radical scavenging, DNA protecting and apoptotic proteins modulating ability against radiation.

Gambogic acid inhibits multiple myeloma mediated osteoclastogenesis through suppression of chemokine receptor CXCR4 signaling pathways.

Bone disease, characterized by the presence of lytic lesions and osteoporosis is the hallmark of multiple myeloma (MM). Stromal cell-derived factor 1α (SDF-1α) and its receptor, CXC chemokine receptor 4 (CXCR4), has been implicated as a regulator of bone resorption, suggesting that agents that can suppress SDF1α/CXCR4 signaling might inhibit osteoclastogenesis, a process closely linked to bone resorption. We, therefore, investigated whether gambogic acid (GA), a xanthone, could inhibit CXCR4 signaling and suppress osteoclastogenesis induced by MM cells. Through docking studies we predicted that GA directly interacts with CXCR4. This xanthone down-regulates the expression of CXCR4 on MM cells in a dose- and time-dependent manner. The down-regulation of CXCR4 was not due to proteolytic degradation, but rather GA suppresses CXCR4 mRNA expression by inhibiting nuclear factor-kappa B (NF-κB) DNA binding. This was further confirmed by quantitative chromatin immunoprecipitation assay, as GA inhibits p65 binding at the CXCR4 promoter. GA suppressed SDF-1α-induced chemotaxis of MM cells and downstream signaling of CXCR4 by inhibiting phosphorylation of Akt, p38, and Erk1/2 in MM cells. GA abrogated the RANKL-induced differentiation of macrophages to osteoclasts in a dose- and time-dependent manner. In addition, we found that MM cells induced differentiation of macrophages to osteoclasts, and that GA suppressed this process. Importantly, suppression of osteoclastogenesis by GA was mediated through IL-6 inhibition. Overall, our results show that GA is a novel inhibitor of CXCR4 expression and has a strong potential to suppress osteoclastogenesis mediated by MM cells.

Herbal drug ninjin'yoeito accelerates myelopoiesis but not erythropoiesis in vitro.

Some Kampo medicines that are herbal and traditional in Japan have had beneficial effects when given to patients with anemia. However, molecular mechanisms underlying their effects are unclear. To address this question, four Kampo medicines used to treat anemia-ninjin'yoeito (NYT), shimotsuto (SMT), juzentaihoto (JTT), and daibofuto (DBT)-were tested separately using in vitro cultures of mouse bone marrow mononuclear cells. Among them, NYT was most effective in stimulating cell proliferation and up-regulating Myc expression. Flow cytometry analysis indicated that, among hematopoietic components of those cultures, myeloid cells expressing CD45/Mac-1/Gr-1/F4/80 increased in number, but Ter119/CD71 erythroid cells did not. Accordingly, real-time PCR analysis showed up-regulation of the myeloid gene Pu.1, whereas the erythroid genes Gata1 and Klf1 were down-regulated. Overall, these findings provide molecular evidence that NYT accelerates myelopoiesis but not erythropoiesis in vitro.

Panax ginseng modulates cytokines in bone marrow toxicity and myelopoiesis: ginsenoside Rg1 partially supports myelopoiesis.

In this study, we have demonstrated that Korean Panax ginseng (KG) significantly enhances myelopoiesis in vitro and reconstitutes bone marrow after 5-flurouracil-induced (5FU) myelosuppression in mice. KG promoted total white blood cell, lymphocyte, neutrophil and platelet counts and improved body weight, spleen weight, and thymus weight. The number of CFU-GM in bone marrow cells of mice and serum levels of IL-3 and GM-CSF were significantly improved after KG treatment. KG induced significant c-Kit, SCF and IL-1 mRNA expression in spleen. Moreover, treatment with KG led to marked improvements in 5FU-induced histopathological changes in bone marrow and spleen, and partial suppression of thymus damage. The levels of IL-3 and GM-CSF in cultured bone marrow cells after 24 h stimulation with KG were considerably increased. The mechanism underlying promotion of myelopoiesis by KG was assessed by monitoring gene expression at two time-points of 4 and 8 h. Treatment with Rg1 (0.5, 1 and 1.5 µmol) specifically enhanced c-Kit, IL-6 and TNF-α mRNA expression in cultured bone marrow cells. Our results collectively suggest that the anti-myelotoxicity activity and promotion of myelopoiesis by KG are mediated through cytokines. Moreover, the ginsenoside, Rg1, supports the role of KG in myelopoiesis to some extent.

Chemoprotective and immunomodulatory effect of Acacia nilotica during cyclophosphamide induced toxicity.

Most of the synthetic chemotherapeutic agents used today are immunosuppressant and lead to numerous side effects. Plant based immunomodulators are employed as supportive therapy to counteract the undesirable side effects of chemotherapy. In the present study, the immunomodulatory and chemoprotective effect of methanolic extract of Acacia nilotica was investigated in mice. Intraperitoneal administration of the extract was found to significantly increase the Total WBC count, bone marrow cellularity and alpha-esterase positive cells. Cyclophosphamide is a chemotherapeutic drug and induces acute myelosuppression but treatment with the extract was beneficial in ameliorating chemically induced toxicity. The administration of the extract considerably increased the Total WBC count (6800 +/- 733.9 cells/cm2), bone marrow cellularity (43.6 x 10(5) +/- 14.33 cells/femur) and alpha-esterase positive cells (808.6 +/- 8.57 cells/4000 cells) in CTX treated mice when compared to CTX alone treated control mice. Weight of lymphoid organs such as spleen and thymus reduced by CTX were enhanced by treatment with Acacia nilotica extract. It can be concluded that the extract possess immunostimulatory properties.

Effects of chemically characterized fractions from aerial parts of Echinacea purpurea and E. angustifolia on myelopoiesis in rats.

Echinacea species are used for beneficial effects on immune function, and various prevalent phytochemicals have immunomodulatory effects. Using a commercial E. purpurea (L.) Moench product, we have evaluated the myelopoietic effect on bone marrow of rats treated with various extracts and correlated this with their chemical class composition. Granulocyte/macrophage-colony forming cells (GM-CFCs) from femurs of female Sprague-Dawley rats were assessed at 24 h after 7 daily oral treatments. A 75% ethanolic extract at 50 mg dried weight (derived from 227 mg aerial parts) per kg body weight increased GM-CFCs by 70% but at 100 mg/kg was without effect. Ethanolic extracts from aerial parts of E. angustifolia DC. var. angustifolia and E. purpurea from the USDA North Central Regional Plant Introduction Station increased GM-CFCs by 3- and 2-fold, respectively, at 200 mg/kg (~1400 mg/kg plant material). Extract from another USDA E. angustifolia was inactive. Proton and APT NMR, MS, and TLC indicated alkylamides and caffeic-acid derivatives (CADs) present in ethanolic extracts of both the commercial and USDA-derived material. Cichoric and caftaric acids were prominent in both E. purpurea ethanolic extracts but absent in E. angustifolia. Aqueous extract of the commercial material exhibited polysaccharide and CAD signatures and was without effect on GM-CFCs. A methanol-CHCl3 fraction of commercial source, also inactive, was almost exclusively 1:4 nonanoic: decanoic acids, which were also abundant in commercial ethanolic extract but absent from USDA material. In conclusion, we have demonstrated an ethanolextractable myelostimulatory activity in Echinacea aerial parts that, when obtained from commercial herbal supplements, may be antagonized by medium-chain fatty acids presumably derived from a non-plant additive.

Angelica sinensis modulates immunohematopoietic response and increases survival of mice infected with Listeria monocytogenes.

The effects of a dry extract of the roots of Angelica sinensis (Oliv.) Diels (ASE) on the growth and differentiation of granulocyte-macrophage progenitor cells (CFU-GM) in normal and Listeria monocytogenes-infected mice were studied. Myelosuppression concomitant with increased numbers of spleen CFU-GM was observed in infected mice. Prophylactic administration of ASE (10, 25, and 50 mg/kg) stimulated marrow myelopoiesis in a dose-dependent manner and reduced spleen colony formation to control values. The dose of 50 mg/kg ASE was the optimal biologically active dose in infected mice, and this dose schedule significantly increased survival of mice infected with a lethal dose of L. monocytogenes, with survival rate up to 30%. Investigation of the production of colony-stimulating factors revealed a dose-dependent increased colony-stimulating activity in the serum of infected mice, with higher response produced by the 50 mg/kg dose. Notably, no effects were observed with the 100 mg/kg dose, compared with infected nontreated controls. Further studies to investigate the production of factors such as inteferon-γ and tumor necrosis factor-α demonstrated increased levels of both cytokines in mice infected with L. monocytogenes and treated with 50 mg/kg ASE. We propose that ASE indirectly modulates immune activity and probably disengages Listeria-induced suppression of these responses by inducing a higher reserve of myeloid progenitors in the bone marrow in consequence of biologically active cytokine release (colony-stimulating factors, interferon-γ, and tumor necrosis factor-α).

Modulatory effects and action mechanisms of tryptanthrin on murine myeloid leukemia cells.

Leukemia is the disorder of hematopoietic cell development and is characterized by an uncoupling of cell proliferation and differentiation. There is a pressing need for the development of novel tactics for leukemia therapy as conventional treatments often have severe adverse side effects. Tryptanthrin (6,12-dihydro-6,12-dioxoindolo-(2,1-b)-quinazoline) is a naturally-occurring, weakly basic alkaloid isolated from the dried roots of medicinal indigo plants (Ban-Lan-Gen). It has been reported to have various biological and pharmacological activities, including anti-microbial, anti-inflammatory, immunomodulatory and anti-tumor effects. However, its modulatory effects and action mechanisms on myeloid cells remain poorly understood. In this study, tryptanthrin was shown to suppress the proliferation of the murine myeloid leukemia WEHI-3B JCS cells in a dose- and time-dependent manner. It also significantly reduced the growth of WEHI-3B JCS cells in vivo in syngeneic BALB/c mice. However, it exhibited no significant direct cytotoxicity on normal murine peritoneal macrophages. Flow cytometric analysis showed an obvious cell cycle arrest of the tryptanthrin-treated WEHI-3B JCS cells at the G0/G1 phase. The expression of cyclin D2, D3, Cdk 2, 4 and 6 genes in WEHI-3B JCS cells was found to be down-regulated at 24 h as measured by RT-PCR. Morphological and functional studies revealed that tryptanthrin could induce differentiation in WEHI-3B JCS cells, as shown by the increases in vacuolation, cellular granularity and NBT-reducing activity in tryptanthrin-treated cells. Collectively, our findings suggest that tryptanthrin might exert its anti-tumor effect on the murine myelomonocytic leukemia WEHI-3B JCS cells by causing cell cycle arrest and by triggering cell differentiation.

Scorpion venom peptides accelerate hematopoietic recovery of myelosuppression in irradiated mice.

Sublethally irradiated mice were administered with scorpion venom peptides (SVP) or with PBS in the saline control group, 3 days before and 7 consecutive days after irradiation. Hematopoietic recovery was assessed by bone marrow (BM) cell proliferation index (PI) and colony forming unit-granulocyte/macrophage (CFU-GM), spleen weight index (SI) and thymus weight index (TI), colony-forming unit-spleen (CFU-S) and peripheral leukocyte counts. In addition, IL-1alpha and SCF levels in BM, IL-6 and GM-CSF levels in serum were determined. In SVP treated groups, PI was improved dramatically versus control mice on day 22 after irradiation. The number of CFU-GM colonies in all SVP treated groups was higher than the control groups. The difference of the number of CFU-GM colonies between SVPV group (0.2 mg/kg) and the control was significant on day 5 and 10 after irradiation (p < 0.05). SVPIV (0.2 mg/kg) could activate the CFU-S formation on day 10 after irradiation. SI was in peak value on day 15 after irradiation in all groups and the SI value of SVPV treated group was higher than control group (p < 0.05). Our results suggest that SVP may be valuable natural peptides that relieve myelosuppression caused by radiation. The effect of SVP accelerating the hematopoietic recovery was potentially through a mechanism of stimulating the release of cytokines.

Comparative acute toxicities and immunomodulatory potentials of five Eastern Nigeria mistletoes.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditionally, mistletoes of Eastern Nigeria origin, Loranthus micranthus Linn. have been used as immunostimulant for the management of certain diseases with high profile immune depleting potentials. This practice has remained till date without scientific validation. AIM OF STUDY: To obtain and validate evidence for or against its continued use as immunostimulant and afford data for further studies on this specie of mistletoe. The present work is an in vivo proof of ethnopharmacological concept of the age long immunomodulatory use of our local mistletoe. MATERIALS AND METHODS: Aqueous-methanol extracts of the plant leaves from five different host trees were evaluated for immunomodulatory activity using four in vivo models in mice or rats, namely; total and differential leukocyte count (TLC and DLC), the cellular mediated delayed-type hypersensitivity reaction (DTHR) test, the humoral mediated antibody titration (AT) test and the cyclophosphamide-induced myelosuppression (CIM) test at different dose levels (100, 200 and 400 or 50, 100 and 250 mg kg(-1); depending on model) against standard controls. Phytochemical and acute toxicity tests were equally carried out on all the extracts. RESULTS: Results obtained indicate that all the mistletoes contained the same phytochemical constituents, although in varying amounts. The mistletoes exhibited statistically significantly different (p < 0.05 or p < 0.001, ANOVA) immunomodulatory (up-regulatory) activities in the overall order of that from Kola acuminata > Citrus spp > Persia americana > Parkia biglobosa > Pentaclatra macrophylla. LD(50) values were generally greater than 5000 mg/kg. CONCLUSION: The present study confirms the Eastern Nigeria mistletoe as a potent and safe alternative or complementary medicine for the management of immunodeficiency diseases.

Comparative studies of the effects of Tabebuia avellanedae bark extract and beta-lapachone on the hematopoietic response of tumour-bearing mice.

The effects of Tabebuia avellanedae (TACE), traditionally prescribed in the treatment of cancer, and the naphtoquinone beta-lapachone (beta-lap) on the growth and differentiation of granulocyte and macrophage progenitor cells (CFU-GM) were studied in Ehrlich ascites tumour-bearing mice. Myelosuppression concomitant with increases in spleen CFU-GM and in serum colony-stimulating activity (CSA) were observed in these animals. Treatment with TACE (30-500 mg/kg) and beta-lap (1-5mg/kg) reversed these effects in a dose-dependent manner. The optimal biologically active doses of 120 mg/kg TACE and 1mg/kg beta-lap prolonged life span of tumour-bearing mice, both producing the same rate of extension in the duration of survival. Toxic manifestations were produced by the higher doses of beta-lap in normal and tumour-bearing mice. In spite of similarities between treatments, TACE concentrations used to treat the animals presented no traces of beta-lap, as measured by TLC and HPLC analyses. Our findings suggest that the antitumour effect of TACE and beta-lap, acting synergistically with other factors, such as specific cytokines, may result from enhanced macrophage activation against tumour cells. In addition, it is clear from our results that hematopoietic disorders produced by tumours are an important pathological condition that must be considered in drug development.