Capacity Of Bone Marrow Cells Research Articles

Ganoderma spore lipid ameliorates docetaxel, cisplatin, and 5-fluorouracil chemotherapy-induced damage to bone marrow mesenchymal stem cells and hematopoiesis

BackgroundA triplet chemotherapy regimen of docetaxel, cisplatin, and 5-fluorouracil (TPF) is used to treat head and neck squamous cell carcinoma; however, it is toxic to bone marrow mesenchymal stem cells (BMSCs). We previously demonstrated that Ganoderma spore lipid (GSL) protect BMSCs against cyclophosphamide toxicity. In this study, we investigated the protective effects of GSL against TPF-induced BMSCs and hematopoietic damage.MethodsBMSCs and C57BL/6 mice were divided into control, TPF, co-treatment (simultaneously treated with GSL and TPF for 2 days), and pre-treatment (treated with GSL for 7 days before 2 days of TPF treatment) groups. In vitro, morphology, phenotype, proliferation, senescence, apoptosis, reactive oxygen species (ROS), and differentiation of BMSCs were evaluated. In vivo, peripheral platelets (PLTs) and white blood cells (WBCs) from mouse venous blood were quantified. Bone marrow cells were isolated for hematopoietic colony-forming examination.ResultsIn vitro, GSL significantly alleviated TPF-induced damage to BMSCs compared with the TPF group, recovering their morphology, phenotype, proliferation, and differentiation capacity (p < 0.05). Annexin V/PI and senescence-associated β-galactosidase staining showed that GSL inhibited apoptosis and delayed senescence in TPF-treated BMSCs (p < 0.05). GSL downregulated the expression of caspase-3 and reduced ROS formation (p < 0.05). In vivo, GSL restored the number of peripheral PLTs and WBCs and protected the colony-forming capacity of bone marrow cells (p < 0.05).ConclusionsGSL efficiently protected BMSCs from damage caused by TPF and recovered hematopoiesis.

Effect of spermidine on radiation-induced long-term bone marrow cell injury.

Spermidine, a natural polyamine, possesses anti-oxidant, autophagy-regulation, and anti-aging properties. Elevated levels of oxidative stress, which was mediated the senescence of hematopoietic stem cells (HSCs) induced by radiation exposure, may further contribute to long-term myelosuppression. Therefore, this study investigated the protective effect of spermidine on the long-term damage of the hematopoietic system caused by radiation exposure. In vitro experiments, bone marrow mononuclear cells (BMMNCs) of C57BL/6 mice were isolated and incubated with 5mM spermidine for 30min, then irradiated by 2Gy X ray. The survival rate, proliferation, and differentiation ability of BMMNCs were detected. In vivo experiment, mice received 4Gy total body irradiation (TBI), 3mM spermidine were administered in the drinking water every day for 14days prior to irradiation and then continued for 30days after irradiation. Peripheral blood, bone marrow cell typing, level of reactive oxygen species (ROS), colony-forming ability of HSC, and transplantation-reconstitution capability were detected. In vitro experiments, spermidine significantly improved the survival rate of BMMNCs as well as the proliferation and differentiation ability of HSCs exposure to ionizing radiation (IR). In vivo, spermidine reduced levels of ROS in HSCs; spermidine attenuated long-term myeloid differentiation deviation induced by TBI. Spermidine promoted the proliferation and differentiation ability of stem cells, but failed to ameliorate the decreased engraftment capacity of bone marrow cells in mice exposed to TBI. This study demonstrated that spermidine could promote the recovery of IR-induced inhibition of proliferation and differentiation ability of HSCs, partly through antioxidant effects. Whether combining spermidine with other radioprotectants could further increase protective efficacy and reduce the long-term bone marrow injury needs further investigation.

Comparing the efficacy of syngeneic iliac and femoral allografts with iliac crest autograft in a rat model of lumbar spinal fusion

BackgroundDespite widespread use of femoral-sourced allografts in clinical spinal fusion procedures and the increasing interest in using femoral reamer–irrigator–aspirator (RIA) autograft in clinical bone grafting, few studies have examined the efficacy of femoral grafts compared to iliac crest grafts in spinal fusion. The objective of this study was to directly compare the use of autologous iliac crest with syngeneic femoral and iliac allograft bone in the rat model of lumbar spinal fusion.MethodsSingle-level bilateral posterolateral intertransverse process lumbar spinal fusion surgery was performed on Lewis rats divided into three experimental groups: iliac crest autograft, syngeneic iliac crest allograft, and syngeneic femoral allograft bone. Eight weeks postoperatively, fusion was evaluated via microCT analysis, manual palpation, and histology. In vitro analysis of the colony-forming and osteogenic capacity of bone marrow cells derived from rat femurs and hips was also performed to determine whether there was a correlation with the fusion efficacy of these graft sources.ResultsAlthough no differences were observed between groups in CT fusion mass volumes, iliac allografts displayed an increased number of radiographically fused fusion masses and a higher rate of bilateral fusion via manual palpation. Histologically, hip-derived grafts showed better integration with host bone than femur derived ones, likely associated with the higher concentration of osteogenic progenitor cells observed in hip-derived bone marrow.ConclusionsThis study demonstrates the feasibility of using syngeneic allograft bone in place of autograft bone within inbred rat fusion models and highlights the need for further study of femoral-derived grafts in fusion.

Abstract 12445: A Detailed Analysis of Peripheral Blood Cytokines 2-3 weeks After Acute Myocardial Infarction: IL-6-Related Impairment of Bone Marrow Function

Background: Intracoronary infusion of bone marrow (BM) mononuclear cells (BM-MNCs) late after acute myocardial infarction (AMI) has shown no improvement in global or regional left ventricular (LV) function (LateTIME and SWISS-AMI). Studies in experimental AMI models suggest a possible cytokine-related depression of progenitor cell function. Furthermore, BM cell content is correlated with the LV functional response. Accordingly, we hypothesize that inflammatory cytokines associated with the late phase of AMI may impair BM function and alter progenitor cell subsets. Method: Patients with previous AMI (n=87) were recruited in a multicenter cell therapy trial by the Cardiovascular Cell Therapy Research Network (CCTRN LateTIME, NCT00684060). BM and peripheral blood (PB) were collected 2-3 weeks after AMI and examined for cell phenotypes and progenitor capacities as well as PB inflammatory and angiogenic cytokines in a core laboratory. Multiple regression analyses were conducted and correlations between cytokine levels and cell phenotypes, cell functions, and post-MI cardiac function were determined. BM from healthy donors, handled in the same manner, was used as a reference. Result: Of 26 cytokines analyzed, IL-6 showed a negative correlation with ECFC colony maximum in BM (estimate±SE (SEE) -0.13±0.04 P=0.007, multivariableR2: 0.59) and Healthy BM showed decreased ECFC colony outgrowth in the presence of IL-6 (P &lt;0.05), in a dose-dependent manner. PDGF-BB positively correlated with CFU-EC colony maximum in BM (SEE 0.006± 0.002, P=0.023, R2: 0.22), MSC colony maximum in BM (SEE 0.006±0.002, P=0.023, R2: 0.17) and MSC colony maximum in PB (SSE 0.018±0.005, P=0.00005, R2:0.24). No significant correlations were found between cardiac function after AMI and PB cytokine levels. Conclusions: At 2-3 weeks after AMI, PB levels of the angiogenic cytokine, PDGF-BB and the pro-inflammatory cytokine, IL-6, were associated with BM cell phenotype and function. IL-6 has the potential to impair endothelial progenitor cell capacity; inhibiting IL-6 may be a target for improving the regenerative capacity of BM cells after AMI.

Inhibition of G9a Histone Methyltransferase Converts Bone Marrow Mesenchymal Stem Cells to Cardiac Competent Progenitors.

The G9a histone methyltransferase inhibitor BIX01294 was examined for its ability to expand the cardiac capacity of bone marrow cells. Inhibition of G9a histone methyltransferase by gene specific knockdown or BIX01294 treatment was sufficient to induce expression of precardiac markers Mesp1 and brachyury in bone marrow cells. BIX01294 treatment also allowed bone marrow mesenchymal stem cells (MSCs) to express the cardiac transcription factors Nkx2.5, GATA4, and myocardin when subsequently exposed to the cardiogenic stimulating factor Wnt11. Incubation of BIX01294-treated MSCs with cardiac conditioned media provoked formation of phase bright cells that exhibited a morphology and molecular profile resembling similar cells that normally form from cultured atrial tissue. Subsequent aggregation and differentiation of BIX01294-induced, MSC-derived phase bright cells provoked their cardiomyogenesis. This latter outcome was indicated by their widespread expression of the primary sarcomeric proteins muscle α-actinin and titin. MSC-derived cultures that were not initially treated with BIX01294 exhibited neither a commensurate burst of phase bright cells nor stimulation of sarcomeric protein expression. Collectively, these data indicate that BIX01294 has utility as a pharmacological agent that could enhance the ability of an abundant and accessible stem cell population to regenerate new myocytes for cardiac repair.

Dietary restriction ameliorates haematopoietic ageing independent of telomerase, whilst lack of telomerase and short telomeres exacerbates the ageing phenotype

Ageing is associated with an overall decline in the functional capacity of tissues and stem cells, including haematopoietic stem and progenitor cells (HSPCs), as well as telomere dysfunction. Dietary restriction (DR) is a recognised anti-ageing intervention that extends lifespan and improves health in several organisms. To investigate the role of telomeres and telomerase in haematopoietic ageing, we compared the HSPC profile and clonogenic capacity of bone marrow cells from wild type with telomerase-deficient mice and the effect of DR on these parameters.Compared with young mice, aged wild type mice demonstrated a significant accumulation of HSPCs (1.3% vs 0.2%, P=0.002) and elevated numbers of granulocyte/macrophage colony forming units (CFU-GM, 26.4 vs 17.3, P=0.0037) consistent with myeloid “skewing” of haematopoiesis. DR was able to restrict the increase in HSPC number as well as the myeloid “skewing” in aged wild type mice. In order to analyse the influence of short telomeres on the ageing phenotype we examined mice lacking the RNA template for telomerase, TERC−/−. Telomere shortening resulted in a similar bone marrow phenotype to that seen in aged mice, with significantly increased HSPC numbers and an increased formation of all myeloid colony types but at a younger age than wild type mice. However, an additional increase in erythroid colonies (BFU-E) was also evident. Mice lacking telomerase reverse transcriptase without shortened telomeres, TERT−/−, also presented with augmented haematopoietic ageing which was ameliorated by DR, demonstrating that the effect of DR was not dependent on the presence of telomerase in HSPCs. We conclude that whilst shortened telomeres mimic some aspects of haematopoietic ageing, both shortened telomeres and the lack of telomerase produce specific phenotypes, some of which can be prevented by dietary restriction.

Effect of Low dose Radiation on Differentiation of Bone Marrow Cells into Dendritic Cells

Low dose radiation has been shown to be beneficial to living organisms using several biological systems, including immune and hematopoietic systems. Chronic low dose radiation was shown to stimulate immune systems, resulting in controlling the proliferation of cancer cells, maintain immune balance and induce hematopoietic hormesis. Since dendritic cells are differentiated from bone marrow cells and are key players in maintaining the balance between immune activation and tolerance, it may be important to further characterize whether low dose radiation can influence the capacity of bone marrow cells to differentiate into dendritic cells. We have shown that bone marrow cells from low dose-irradiated (γ-radiation, 0.2Gy, 15.44mGy/h) mice can differentiate into dendritic cells that have several different characteristics, such as expression of surface molecules, cytokine secretion and antigen uptake capacity, when compared to dentritic cells differentiated from the control bone marrow cells. These differences observed in the low dose radiation group can be beneficial to living organisms either by activation of immune responses to foreign antigens or tumors, or maintenance of self-tolerance. To the best of our knowledge, this is the first report showing that total-body low dose radiation can modulate the capacity of bone marrow cells to differentiate into dendritic cells.

PML is a key component for the differentiation of myeloid progenitor cells to macrophages

IFN regulatory factor-8 (IRF-8, previously known as ICSBP) is a key transcription factor driving the differentiation of granulocyte\monocyte progenitor (GMP) cells toward monocyte\macrophage lineage. The promyelocytic leukemia (PML) gene is an immediate target gene regulated by IRF-8 in response to IFN-γ activation. PML is a multifunctional protein that has many isoforms serving as the scaffold components for nuclear bodies (NBs) engaged in numerous proteins interactions. The role of PML in the retinoic acid pathway that drives GMPs to granulopoiesis is documented in the literature. Here, we show that PML is also involved in monopoiesis by mediating some of the IRF-8 activities during the differentiation of murine-derived bone marrow macrophages (BMMs). PML silencing resulted in altered expression level of key transcription factors essential for monopoiesis that was accompanied by silencing of typical myeloid-specific genes. Interestingly, this altered expression resembled that of the GMPs and that of BMMs derived from IRF-8(-/-) mice altogether supporting the role of PML in monopoiesis. Further, PML silencing led to reduced colony-forming capacity of bone marrow cells highlighting the dual function of PML in myelopoiesis. Last, PML overexpression only partially rescued the phenotype of IRF-8(-/-) BMMs. Together, our data show that PML is an important factor for monopoiesis and not solely for granulopoiesis. This suggests that PML-NBs respond to an incoming signal that affects the fate of GMP driving cell differentiation to granulocytes or monocytes.

Bone Marrow-Derived Cells Promote Liver Regeneration in Mice With Erythropoietic Protoporphyria

Bone marrow transplantation can reverse hepatic protoporphyrin accumulation and prevent the hepatobiliary complications characteristic of erythropoietic protoporphyria. The aim of this study was to assess the recruitment capacity of bone marrow cells in the damaged liver and their possible contribution to the improved or recovered hepatic function in a murine model of erythropoietic protoporphyria (EPP). Lethally irradiated female EPP mice were transplanted with bone marrow cells from healthy male mice and were monitored during 12 or 36 weeks. Two groups of animals killed 12 weeks after transplant were also treated with granulocyte colony-stimulating factor. Cell transplantation decreased porphyrin contents in erythrocytes and liver. Improved hepatic structure and function and reduced hepatic fibrosis were observed, especially 36 weeks after transplant. Bone marrow-derived cells (22%-35%) were identified in the liver of recipient mice by means of fluorescence in situ hybridization (chrY-FISH) or green fluorescent protein staining and were characterized by immunofluorescence staining. The livers of recipients contained 20% to 30% myofibroblasts (alpha-smooth muscle actin-positive cells), 40% CK19-positive cells, and 10% to 28% hepatocytes (albumin-positive cells) derived from the donor bone marrow. Bone marrow-derived cells play a significant role in restoring and regenerating hepatic tissue in EPP mice. Hepatic repair was associated with fibrogenesis, enhanced by granulocyte colony-stimulating factor treatment, and almost normal liver structure and function was observed in the long term (36 weeks posttransplant).

BONE MARROW CELLS VERSUS MATURE LYMPHOCYTES AND MONOCYTES - CAPACITY OF IMMUNOTOLERANCE INDUCTION IN COBB 500 HYBRIDS

The purpose of this study was the comparison between capacity of bone marrow cells on the one hand, and of mature lymphocytes and monocytes on the other hand, to induce immunotolerance by inoculation in COBB 500 hybrids at different embryonic stages. Antigeni c material was obtained by aspiration of tibial and femoral bone marrow, respectively by blood sampling from the donor birds (Ross hybrids).We used 240 embryonated eggs: 60 eggs for in ovo inoculation with bone marrow cells suspension in t he 5 th day of embryo development and 60 for inoculation in the same way and day with mature lymphocytes and monocytes suspension; the rest of biol ogic material was inoculated with these suspensions in a llantoidal vessel in the 8 th day of the embryo. Seven days after the full-thickness skin grafts transplantation (fro m the donor birds) the lymphocyte T subsets of the recipient birds were determined by flow cytometry and immunomagnetic sorting. Also, all the skin grafts were periodica lly monitored for macroscopic characteristics. This exp eriment demonstrates the superiority of bone marrow cells in immunotolerance induction in birds after inoculatio n in 5 th day of embryonic development.

Reply to Letter from Drs. Haider and Ashraf

Dear Editor, It was proposed by Haider and Ashraf1 that cytokine and growth factor mediated mobilization of endogenous mesenchymal stem cells from their bone marrow niches for homing into the infarcted myocardium could be a better therapeutic strategy than the explantation and subsequent injection of these cells (either autologous or from a donated allogenic source) directly into the damaged heart.2 Besides being less invasive to the patient, it was argued that this approach would obviate the need for ex vivo processing of the putative stem cells, which could in turn reduce the risk of nonspecific differentiation into undesired lineages at the transplantation site.3–5 Nevertheless, such an approach could be severely hampered by the age related decline in the regenerative capacity of the putative mesenchymal stem cell population within the bone marrow, as has been demonstrated by a number of studies.6,7 It must be remembered that the overwhelming majority of myocardial infarct cases occur in the older segment of the population.8 Quarto and colleagues6 demonstrated in a rat model that there was an age associated decline in the ability of marrow stromal cells to repair bone, which could be the underlying cause of age related osteodegenerative diseases. Subsequently, D’Ippolito and colleagues7 reported a similar finding with the human model. This would be expected because, with increasing age, the putative mesenchymal stem cell population within the bone marrow would have gone through more rounds of cell division, in addition to having been exposed to free radicals and metabolic toxins over a longer lifespan. Hence it is no surprise that there is a gradual decline in their regenerative capacity with increasing age. Although there have been no studies to date that have conclusively demonstrated an age associated decline in the capacity of bone marrow cells to repair the infarcted heart, we could make such a conjecture based upon extrapolation from the bone repair model.6,7 The obvious solution to overcome this age related decline in regenerative capacity would be to look at donated allogenic sources of stem cells for myocardial repair. In this regard, human embryonic stem (hES) cells or their differentiated progenies would hold much promise because these potentially represent an abundant and readily available source of transplantable cells. Recently, Zandstra and colleagues9 successfully developed a scalable, robust, and reproducible process for obtaining purified cardiomyocytes from hES cells. Nevertheless, the immunologic barrier10 probably represents the most formidable challenge to the allogenic transplantation of hES cells or their differentiated progenies into the infarcted myocardium. It is hoped that this could somehow be overcome in the near future. Boon Chin Heng* Eugene Kwang-Wei Sim† Tong Cao* *Stem Cell Laboratory, Faculty of Dentistry, †Department of Surgery, Faculty of Medicine National University of Singapore.

Modification of the clonogenic capacity of bone marrow cells from normal individuals by the tyrosine kinase inhibitor STI571.

STI571 shows clinical activity in the treatment of chronic myelogenous leukemia, Philadelphia positive acute lymphoblastic leukemia and gastrointestinal stromal tumors. Resistance of normal progenitor cells to STI571 is essential when determining the optimal therapeutic window for patients with cancer without bone marrow involvement, and for patients with chronic myeloid leukemia who achieved complete cytogenetic remission. The effect of graded concentrations of STI571 on the clonogenic potential of normal fresh bone marrow hematopoetic progenitor cells from 13 normal individuals was analyzed. It was shown that lower concentrations of STI571 (0.1 and 0.5 microM/l) may increase colony numbers, whereas higher concentrations (>1 microM/l) may reduce normal colony formation.

Enhanced proliferation of functionally competent bone marrow cells in different strains of mice treated with swainsonine

The immunomodulatory alkaloid swainsonine (8αβ−indolizidine-1α,2α,8β-triol) has potential for overcoming the bone marrow suppressive effects of cancer chemotherapy and radiotherapy. An earlier study showed that multiple doses of swainsonine enhanced bone marrow cellularity in four different strains (C57BL/6; C3H-HEN; Balb/C and DBA-2 mice) of inbred mice which were not exposed to any chemotherapeutic agents or radiation. In vitro assessment of total colony formation capacity of bone marrow cells (BM CFUs) showed a 2- to 8-fold increase in swainsonine-treated mice compared to control mice that were given sham injections of physiological saline. In the current study, we have evaluated the functional competence of the bone marrow cells produced in response to swainsonine treatment of normal healthy mice. In particular, colony forming units-granulocyte–macrophage (CFU-GM), erythroid-burst forming units (BFUe) and CFU-Mix (or CFU-granulocyte–erythrocyte–monocyte–megakaryocyte (CFU-GEMM)) levels, were determined using in vitro assays. The time course of the changes in CFU-GM, BFUe and CFU-Mix (CFU-GEMM) were also followed. Our results demonstrate that swainsonine bolsters the CFU capacity of BM cells without loss of function to levels which are several folds higher than in sham-treated control mice. Swainsonine treatment caused an increase in all lineages of marrow cells without loss of function. This effect was reproduced in all four strains of inbred mice in this investigation. Examination of the peripheral blood did not reveal increase in white blood cells or changes in the hematocrit levels. The long-term effects of swainsonine treatment are not known at present. Nonetheless, swainsonine-induced increase in CFU capacity of bone marrow cells and related cells along the different differentiation paths should find clinical application in cancer treatment with chemotherapeutic agents and/or radiation.

Swainsonine stimulates bone marrow cell proliferation and differentiation in different strains of inbred mice

The immunomodulatory alkaloid swainsonine (8αβ-indolizidine-1α,2α,8β-triol) has potential for overcoming the bone marrow suppressive effects of cancer chemotherapeutic drugs and radiation. The effect of swainsonine on bone marrow cellularity was evaluated in four different strains (C57BL/6; C3H-HEN; Balb/C and DBA-2 mice) of inbred mice subjected to multiple doses of the alkaloid. Swainsonine treatment stimulated bone marrow cell proliferation in all strains of mice. Examination of the peripheral blood did not reveal any increase in total leukocyte count. In vitro assessment of total colony-forming unit (CFU) capacity of bone marrow cells showed a two- to eight-fold increase in swainsonine treated mice of different strains compared to their corresponding controls given sham injections of physiological saline. Swainsonine induced increase in CFU capacity of bone marrow cells should find clinical application in cancer treatment with chemotherapeutic agents and radiation.

Células estromales de la médula ósea: una fuente terapéutica alternativa en la restauración de enfermedades degenerativas del sistema nervioso central

Aims. The aim of this study is to describe the capacity of bone marrow cells to limit or slow down the damage and chronic neuronal degeneration produced by degenerative diseases of the central nervous system (CNS), as well as the potential capacity of the method to provide other substances or genetic material. Development. The search for new sources of cells that maintain the ability to divide and distinguish themselves from different cellular phenotypes opens up huge new opportunities in the restorative therapy ofthese clinical entities. Bone marrow cells, and especially stromal stem cells, have been seen to conserve a high capacity to distinguish and originate different strains of characteristic brain cells (neurons, astrocytes, and glial cells), and also the capacity to restore the population of stem cells when they are stimulated in a suitable fashion. Conclusions. Future experimentalstudies will be aimed at searching for new ways to enhance the composition, viability and differentiation ofthe cells to be implanted and will evaluate their effects on diseases of the CNS.

Effects of prolactin deficiency on myelopoiesis and splenic T lymphocyte proliferation in thermally injured mice.

The importance of prolactin (PRL) in mammopoiesis and milk production is undisputed. However, previous studies investigating the role of PRL in immune function have yielded inconsistencies. These inconsistencies have led to our hypothesis that the immunomodulatory effects of PRL are only manifest under conditions in which the organism is subjected to stress. Thermal injury is a well-known stressor. The goal of this study was to determine whether the lack of PRL enhanced the negative effects of thermal injury-induced immune alterations utilizing a mouse model in which the PRL gene had been disrupted. Mice received either sham or burn treatment, and were sacrificed 4 days later. The immune parameters studied were the capacity of bone marrow cells to form granulocyte-macrophage colony forming units (GM-CFU) in the presence of granulocyte-macrophage colony stimulating factor, and the ability of the splenic T lymphocytes to proliferate in response to phytohemagglutin (PHA). As shown by others, our results reveal that burn increased the number of GM-CFU compared to sham controls; however, this elevation was only significant in the PRL-/- mice. Thermal injury increased PHA-stimulated proliferation of splenic T lymphocytes, however this increase was only significant in the PRL+/- group. We conclude that under conditions of a controlled stress event (thermal injury) [a] the increase in the GM-CFU is exaggerated in the absence of PRL, and [b] the enhancement of PHA-induced proliferation of splenic lymphocytes required PRL. This study supports the hypothesis that the immunomodulatory effects of PRL are manifest when the organism is subjected to stress.

Agar cultures of human clonogenic hemopoietic precursor cells for early diagnosis of some myeloproliferative diseases.

Growth characteristics of human hemopoietic cells in erythremia and chronic myeloid leukemia were studied using agar cultures with and without hemopoietic growth factors. Agar cultures, similarly to cultures on other semisolid media (plasma clot, methylcellulose) can be used for early differential diagnosis of polycythemia vera (erythremia) and secondary erythrocytosis: erythremia, but not erythrocytosis, is characterized by spontaneous (erythropoietin-independent) formation of colonies from erythrocyte precursor cells. Spontaneous colony formation from granulocyte-macrophage precursor cells can serve as an important test for early diagnosis of chronic myeloid leukemia. The study of colony formation from granulocyte-macrophage precursors and of the capacity of bone marrow cells to form colonies from hemopoietic stromal precursor cells revealed new characteristics of the studied myeloproliferative diseases. Presumably, spontaneous colony formation from erythrocytic and myeloid precursors should be regarded as a sign of tumor transformation of the studied hemopoietic cells.

Genetic variability in the response of normal murine hematopoietic progenitor cells to photochemical purging

Abstract The photosensitizer, Merocyanine 540 (MC540) is currently undergoing phase I/II clinical evaluation as a purging agent for autologous stem cell grafts from patients with AML, ALL, CML, HD, and NHL. The preclinical data that provide the basis for these trials were mostly conducted in or with cells from B6D2F1 and B6AF1 mice. These experiments indicated that combinations of MC540 and light that deplete leukemia cells by 5–8 log deplete granulocyte/macrophage progenitors (CFU-GM) and the radio-protective capacity of bone marrow cells by about 1 log. We have recently shown that hematopoietic cells from 129 mice are substantially less sensitive to MC540-purging than cells from B6D2F1, B6AF1, and C57BL/6 mice. For instance, a combination of MC540 and light that depletes CFU-GM from C57BL/6mice 7.9 fold, depletes CFU-GM from 129 and B6129F1 mice merely 1.4-fold and 2-fold, respectively. This marked difference in photosensitivity cannot be explained by strain-specific differences in the ratio of photosensitive granulocye (CFU-G to photoresistant macrophage (CFU-M) progenitors, as the same rank order of sensitivity is also observed among unipotent CFU-G and CFU-GM as well as among erythroid progenitors from 129, B6129F1, and C57BL/6 mice.Flow cytometric binding studies show increased binding of MC540 to bone marrow cells from C57BL/6 mice, suggesting that the greater photosensitivity of C57BL/6 cells is at least in part attributable to a greater expression of MC540 binding sites in C57BL/6 marrow cells. These findings have obvious implications for the preclinical and clinical evaluation of merocyanines and related purging agents. They also suggest new experimental approches for investigations into the genetic control of photosensitivity.

Gene transfer to suppress bone marrow alkylation sensitivity.

Alkylating agents represent a highly cytotoxic class of chemotherapeutic compounds that are extremely effective anti-tumor agents. Unfortunately, alkylating agents damage both malignant and non-malignant tissues. Bone marrow is especially sensitive to damage by alkylating agent chemotherapy, and is a dose-limiting tissue when treating cancer patients. One strategy to overcome bone marrow sensitivity to alkylating agent exposure involves gene transfer of the DNA repair protein O(6)-methylguanine DNA methyltransferase (O(6)MeG DNA MTase) into bone marrow cells. O(6)MeG DNA MTase is of particular interest because it functions to protect against the mutagenic, clastogenic and cytotoxic effects of many chemotherapeutic alkylating agents. By increasing the O(6)MeG DNA MTase repair capacity of bone marrow cells, it is hoped that this tissue will become alkylation resistant, thereby increasing the therapeutic window for the selective destruction of malignant tissue. In this review, the field of O(6)MeG DNA MTase gene transfer into bone marrow cells will be summarized with an emphasis placed on strategies used for suppressing the deleterious side effects of chemotherapeutic alkylating agent treatment.

Impact of experimental peritonitis on bone marrow cell function

Background: The effects of abdominal sepsis on the regulation of cell turnover in bone marrow and on the function of hematopoietic stem cells were investigated. Methods: In a new mouse model of abdominal sepsis (colon ascendens stent peritonitis [CASP]) the proliferation, apoptosis, and colony-forming capacity of bone marrow cells were determined. Results: Both experimental peritonitis and sham surgery increased proliferation of bone marrow cells significantly (P <.01). Incubation with granulocyte-macrophage colony-stimulating factor but not granulocyte colony-stimulating factor further augmented proliferation of bone marrow cells from septic mice. In contrast to cell proliferation, bone marrow cell apoptosis was significantly (P <.001) increased in response to CASP but not to sham surgery. CASP surgery and treatment of normal bone marrow cells with lipopolysaccharide, tumor necrosis factor-α, interleukin 1β, and interferon gamma increased the number of apoptotic cells to a similar extent. Stem cell assays revealed that during the late phase of peritonitis the colony formation by granulocytic-monocytic precursors was increased, whereas mature erythroid colony-forming cells were suppressed. Incubation of normal bone marrow cells with lipopolysaccharide and cytokines showed similar effects. Conclusions: These results reveal differential effects of experimental peritonitis on various hematopoietic lineages and suggest a potential role of inflammatory mediators for the dysregulation of bone marrow cell function during abdominal sepsis. (Surgery 1999;126:41-7.)