The proliferative capacity of pure red cell aplasia bone marrow cells.

Pure red cell aplasia (PRCA) is a heterogeneous disorder. Immunologic abnormalities have recently been uncovered suggesting that both cell-mediated and humoral immune mechanisms may be of etiological importance in PRCA. Utilizing a technique for the cloning of bone marrow erythroid precursors, we determined the in vitro proliferative capacity of erythroid cells obtained from 21 patients with PRCA. Bone marrow cells from one group of patients produced normal or increased numbers of erythroid colonies while the in vitro proliferative capacity of bone marrow cells from a second group was characterized by subnormal erythroid colony formation. Sera obtained from the former group was frequently associated with demonstrable serum inhibitors of erythropoiesis, while PRCA in the latter group was probably the consequence of intrinsic erythroid stem cell defects or pathologic cellular interactions with nonerythroid regulatory cells. This survey of a relatively large population of patients with PRCA provides evidence for the multiple causative mechanisms that can be operative in the production of PRCA.     

Pre CFU-F in bone marrow cultures from children with hematopoietic disease including acute leukemia

Stromal precursor cells from bone marrow aspirates of children have been studied in culture. In 7 day liquid cultures normal individuals and patients with acute leukemia in remission grew 110 +/- 50 CFU-F and 100 +/- 40 CFU-F (colony forming unit--fibroblasts) respectively, per 6 X 10(5) buffy coat mononuclear cells. Staining with monoclonal antibodies suggests that stromal cells from CFU-F colonies are fibroblasts. CFU-F colony growth from the bone marrow of patients with active leukemia was low. After cultivation periods of more than 21 days, we observed, in addition, still more immature, clonogenic fibroblast precursor cells, "pre CFU-F", and round cells attached to stromal cells from pre CFU-F colonies. From the round cells, we have passaged pre CFU-F and CFU-GM (colony forming unit--granulocytic, monocytic) in secondary cultures. Our observations are in agreement with the concept that the bone marrow stromal cell matrix serves as a sanctuary for reversibly attached clonogenic cells of both the hematopoietic and fibroblast lineages.     

Stimulation by normal and leukemic mouse sera of colony formation in vitro by mouse bone marrow cells

Using a modification of the agar gel method for bone marrow culture, serum from various strains of mice has been tested for colony stimulating activity. Ninety percent of sera from AKR mice with spontaneous or transplanted lymphoid leukemia and 40–50% of sera from normal or preleukemic AKR mice stimulated colony formation by C57B1 bone marrow cells. Sera from 6% of C3H and 30% of C57B1 mice stimulated similar colony formation. The incidence of sera with colony stimulating activity rose with increasing age. All colonies were initially mainly granulocytic in nature but later became pure populations of mononuclear cells. Bone marrow cells exhibited considerable variation in their responsiveness to stimulation by mouse serum. Increasing the serum dose increased the number and size of bone marrow cell colonies and with optimal serum doses, 1 in 1000 bone marrow cells formed a cell colony. Preincubation of cells with active serum did not stimulate colony formation by washed bone marrow cells. The active factor in serum was filterable, non-dialysable and heat and ether labile.     

Fibroblast colonies in monolayer cultures of human bone marrow

In a liquid culture of human bone marrow, the development of fibroblast colonies takes place on days 6 to 9. Twenty percent fetal calf serum is used as the stimulus for fibroblast colony growth. Human bone marrow cells are plated as 2 × 10₅ cells in the culture. Normal human bone marrow yields 47 ± 4 fibroblasts colonies per 2 × 10₅ cells plated. Bone marrow fibroblast cultures using agar or methylcellulose restrict colony formation. Marked colony suppression was observed in acute leukemia, and a discrete colony number was observed in hypoplastic anemia. This fibroblast culture method should be applied to a larger number of patients to determine whether it has a pathognomonic value and clinical significance.     

Granulopoietic studies in acute lymphocytic leukemia of children.

Studies have been carried out on the levels of serum and urine colony stimulating activity (CSA) and peripheral blood and bone marrow colony forming cell numbers in children with acute lymphocytic leukemia (ALL) during various phases of their disease. These studies have suggested that serum and urine levels of colony stimulating factor are reduced during the inital or relapse phase of the disease compared to levels found during remission. It has also been found that the number of bone marrow colony forming cells is reduced in relapse or before treatment and elevated during remission while the number of peripheral blood colony forming cells is increased during relapse or before treatment and normal during remission. It has also been shown that mixing of serum or leukemic cells with normal human bone marrow cells inhibits colony formation.     

CFU-gm colony formation of peripheral blood and bone marrow in adult acute leukemia at presentation, during remission, and at relapse

Granulocyte/macrophage colony-forming unit (CFU-gm) formation was studied simultaneously in bone marrow and peripheral blood of 52 previously untreated adult patients with acute non-lymphocytic (ANLL) and 36 with acute lymphoblastic leukemia (ALL). They were followed during induction therapy at monthly intervals while in remission and in 19 ANLL and 22 ALL cases, until relapse. Patients showing a decreased colony number in the marrow but normal or increased colony numbers in the peripheral blood had a high probability of entering remission. Non-responding patients displayed an opposite pattern. The higher the degree of marrow repopulation with granulocytic progenitor cells after induction treatment, the longer remission duration and survival for ANLL patients and the longer survival for ALL patients. CFU-gm formation returned to normal in the early stages of complete remission, but then declined progressively. At ANLL and ALL relapse, colony growth was reduced markedly while cluster formation remained normal. The number of marrow colonies and clusters in ANLL were significantly higher at first and second relapse compared to the growth pattern at first presentation. A similar trend had been observed in ALL, suggesting a selection advantage.     

New insights into the regulation of human megakaryocytopoiesis

It is apparent that multiple cellular stages and biologic processes can be identified during megakaryocytopoiesis that are potentially subject to control by hematopoietic growth factors and marrow accessory cell populations. Two classes of megakaryocyte progenitor cells, the colony forming unit-megakaryocyte (CFU-MK) and the burst forming unit-megakaryocyte (BFU-MK), have now been detected in normal human bone marrow cells. The BFU-MK by virtue of the greater cellular content of its resultant colonies and the delayed time of appearance of these colonies appears to be a more primitive progenitor cell with a greater proliferative potential than the CFU-MK. A number of hematopoietic growth factors including megakaryocyte colony stimulating factor, (MK-CSF), recombinant erythropoietin (EPO) and granulocyte macrophage colony stimulating factor (GM-CSF) are each capable of increasing cloning efficiency of human megakaryocyte progenitor cells. It is presently unknown whether these factors act directly on the CFU-MK or whether they stimulate marrow accessory cells to elaborate growth factors that influence CFU-MK proliferation. In order to answer this question, the effect of these growth factors on the cloning efficiency of a human megakaryocytic cell line, EST-IU, was examined. Each of these factors was capable of increasing leukemia cell colony formation. One can conclude from these studies that MK-CSF, EPO, and GM-CSF act directly on cells of the megakaryocytic lineage. The physiologic significance of the lineage nonspecific effects of EPO and GM-CSF on megakaryocytopoiesis is yet to be determined. On the basis of these observations, a model of human megakaryocytopoiesis was suggested. Several factors appear able to influence multiple steps in megakaryocytic development, whereas others influence only specific stages or cellular events occurring during megakaryocytopoiesis.     

Clonogenic stromal cell count in the bone marrow of mice

The number of fibroblast colonies in bone marrow cultures depends on FCFC concentration in explanted cells and FCFC cloning efficiency. For mouse bone marrow the efficiency of fibroblast colony formation increases in the presence of the feeder (irradiated bone marrow of spleen cells). Colony-stimulating feeder activity does not depend on the presence of phagocytic and stromal cells in the feeder cell population. Trypsinization of the bone marrow leads to the release of additional FCFC and the increase of their concentration in bone marrow cell suspensions.     

The suppressive influences of human tumor necrosis factors on bone marrow hematopoietic progenitor cells from normal donors and patients with leukemia: synergism of tumor necrosis factor and interferon-gamma

The influences of human tumor necrosis factor (TNF) (LuKII), recombinant human TNF-alpha, natural human interferon-gamma (HuIFN-gamma), recombinant HuIFN-gamma, and natural HuIFN-alpha were evaluated alone or in combination for their effects in vitro on colony formation by human bone marrow granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) progenitor cells incubated at 5% CO2 in lowered (5%) O2 tension. TNF (LuKII) and recombinant TNF-alpha caused a similar dose-dependent inhibition of colony formation from CFU-GM, BFU-E, and CFU-GEMM. Day 7 CFU-GM colonies were more sensitive than both day 14 CFU-GM colonies and day 7 CFU-GM clusters to inhibition by TNF. BFU-E colonies and CFU-GEMM colonies were least sensitive to inhibition with TNF. The suppressive effects of TNF (LuKII) and recombinant TNF-alpha were inactivated respectively with hetero-anti-human TNF (LuKII) and monoclonal anti-recombinant human TNF-alpha. The hetero-anti-TNF (LuKII) did not inactivate the suppressive effects of TNF-alpha and the monoclonal anti-recombinant TNF-alpha did not inactivate TNF (LuKII). The suppressive effects of TNF did not appear to be mediated via endogenous T lymphocytes and/or monocytes in the bone marrow preparation, and a pulse exposure of marrow cells with TNF for 60 min resulted in maximal or near maximal inhibition when compared with cells left with TNF for the full culture incubation period. A degree of species specificity was noted in that human TNF were more active against human marrow CFU-GM colonies than against mouse marrow CFU-GM colonies. Samples of bone marrow from patients with non-remission myeloid leukemia were set up in the CFU-GM assay and formed the characteristic abnormal growth pattern of large numbers of small sized clusters. These cluster-forming cells were more sensitive to inhibition by TNF than were the CFU-GM colonies and clusters grown from the bone marrow of normal donors. The sensitivity to TNF of colony formation by CFU-GM of patients with acute myelogenous leukemia in partial or complete remission was comparable with that of normal donors. When combinations of TNF and HuIFN were evaluated together, it was noted that TNF (LuKII) or recombinant TNF synergized with natural or recombinant HuIFN-gamma, but not with HuIFN-alpha, to suppress colony formation of CFU-GM, BFU-E, and CFU-GEMM from bone marrow of normal donors at concentrations that had no suppressive effects when molecules were used alone.(ABSTRACT TRUNCATED AT 400 WORDS)     

The effect of cryopreservation on committed stem cells (CFU-c's) in humans

The effects of different sources of colony-stimulating factor (CSF) and of cryopreservation have been studied on committed stem cells (CFU-c's) in bone marrow aspirates from patients with nonhematological ailments, acute leukemia (AL) in remission, and solid tumors, and in peripheral blood from patients with chronic myeloid leukemia (CML).Results showed significant effects due to the source of CSF and to freezing, colony scores being reduced on human placental-conditioned medium (HPCM) after freezing, whereas they remained the same or were increased on peripheral leukocyte underlayers (PBU). An analysis of the differential morphology of the CFU-c's showed that the ratio of eosinophil to polymor-phonuclear colonies was significantly lower on HPCM and after freezing on both sources of CSF.     

Cloning stem cells in the bone marrow of irradiated mice]

Different amount of intact or irradiated bone marrow from syngenous donors was administered to mice irradiated with a lethal dose. There was revealed a linear dependence of the number of the 8-9-day colonies grown in the bone marrow of the femur on the amount of the administered cells, and an exponential dependence on the irradiation dose. Regularity of the stem cell cloning in the bone marrow was analogous to such in the spleen. Radiosensitivity of the colony-forming units (CFU) differed depending on the site (the spleen, the bone marrow) of their colony formation. The CFU settling in the marrow proved to be more radioresistant (D(0) equalled 160-200 P) in comparison with the CFU settling in the spleen (D(0) constituted 80-100 P). It is supposed that a different radiosensitivity of the CFU was caused by the presence of heterogenic population of the stem cells and also by specific peculiarities of the organ (the spleen, the bone marrow) in which the colonies formed.     

A subline of the Brown Norway myeloid leukemia in the Lewis x Brown Norway rat: in vivo growth characteristics and development of an in vitro clonogenic assay

A subline of Brown Norway (BN) acute myelocytic leukemia (AML) which can be propagated in suspension culture (designated IPC-81) is described. Injection into Lewis x BN F1 hybrid (LBN) rats resulted in a log-linear correlation between tumor cell dose and time till death from the onset of leukemia even after multiple (greater than 16) passages in vitro. An in vitro clonogenic assay for IPC-81 colony formation (CFU-leuk) was developed with excellent cloning efficiency (55-82%). Colonies grew without the addition of specific growth factors; syngeneic spleen-conditioned medium inhibited CFU-leuk by 40%, but co-culture with untreated normal LBN rat bone marrow cells had no effect on CFU-leuk. CFU-leuk could be detected in the bone marrow 7 to 10 days before morphologic detection of leukemia in injected animals. This cell line should prove useful in the preclinical evaluation of new strategies for treating AML and evaluating new bone marrow purging methods.     

Murine and human hematopoietic colony formation: a possible regulatory role for intracellular histamine

Increasing number of data suggests that locally produced histamine is involved in regulation of hematopoiesis. In this study the granulocyte/macrophage (CFU-GM) colony formation by normal murine or human bone marrow cells, leukaemic colony formation (CFU-L) by a murine leukemia cell line (WEHI 3B), and colony formation by bone marrow cells from patients with chronic myeloid leukemia (CML) have been examined. We detected mRNA and protein expression of histidine decarboxylase (HDC), the only enzyme responsible for histamine synthesis both in normal bone marrow progenitor cells and in leukaemic progenitors. The significance of in situ generated histamine was shown on colony formation by inhibitory action of alphaFMH (blocking HDC activity, i.e. de novo histamine formation) and by N,N-diethyl-2-[4-(phenylmethyl)phenoxy]-ethanamine-HCl (DPPE) disturbing the interference of histamine with intracellular binding sites. These data provide further confirmation of the role of histamine in development and colony formation of bone marrow derived cells.     

DNA topoisomerase inhibitors block erythropoiesis and delay hemoglobinization in vitro

To examine the importance of topological constraints on DNA during erythroid development, we measured the effects of camptothecin and teniposide, two tumoricidal agents which are also specific inhibitors of type I and type II topoisomerases respectively, on the formation of hematopoietic colonies by cultured human bone marrow cells. When added to bone marrow culture, each inhibitor alone impairs the formation of early BFU-E-derived colonies, late CFU-E-derived colonies and mixed hematopoietic (CFU-GEMM-derived) colonies by up to 100%. Inhibition of colony formation is directly related to the time of inhibitor addition and the inhibitor concentration tested. Although either inhibitor alone reduces colony formation by 90%, when added together at a submaximal concentration, camptothecin and teniposide exert a synergistic suppressive effect. Furthermore, addition of topoisomerase inhibitors to culture impairs hemoglobinization of colony erythroblasts in a time-dependent fashion. In contrast to the effects of topoisomerase inhibitors, the antiproliferative agent aphidicolin reduces erythroid colony number and size without altering hemoglobinization of colony erythroblasts. Since neither topoisomerase inhibitor alters the morphology of cultured cells, the capacity of cells to exclude trypan blue or the potential to form erythroid colonies through the interval required for the first progenitor cell division, it is unlikely that camptothecin or teniposide are cytotoxic to hematopoietic cells. Human mononuclear cells enriched in bone marrow lymphocytes and nucleated erythroblasts from both human and mouse sources release DNA into the detergent soluble fraction. Release requires functional topoisomerases and is altered by acute exposure to topoisomerase inhibitors. Our results suggest that topoisomerases are critical not only to proliferation but also to differentiation of human marrow erythroid progenitor cells and stem cells in culture.     

The continued requirement for inducer for the development of macrophage and granulocyte colonies

Rat bone marrow cells were seeded as mass cultures or for cloning together with inducer required for colony formation, and at various times after seeding, the cells were re-seeded for cloning either with or without inducer. The results indicate that the development of both macrophage (M) and granulocyte (G) colonies requires a continued supply of the inducer. No M or G colonies were produced when the inducer was replaced by erythropoietin.     

Depression of bone marrow colony formation in gold-induced neutropenia.

Bone marrow culture in semi-solid agar was used to assess the proliferative activity and the response to sodium aurothiomalate of the myeloid precursor cells from patients during and after recovery from neutropenia associated with the use of this drug. Colony formation was reduced during the neutropenia and returned to normal after recovery. The rheumatoid process itself did not impair colony formation even in patients with Felty''s syndrome. Sodium aurothiomalate inhibited colony formation by normal marrow in a dose-dependent manner. Bone marrow colonies from patients who had recovered from neutropenia induced by sodium aurothiomalate were not abnormally sensitive to the inhibitory effect of the drug in vitro. The metabolism of gold is probably altered in a small proportion of patients, which causes high local concentrations within the bone marrow leading directly to marrow depression.     

The suppressive effects of recombinant human tumor necrosis factor-alpha on normal and malignant myelopoiesis: synergism with interferon-gamma

The modulation of growth of normal and leukemic myeloid progenitor cells in soft agar cultures by recombinant human tumor necrosis factor-alpha (TNF alpha) and recombinant human interferon-gamma (IFN gamma) was investigated. TNF alpha inhibited colony formation of all colony types representing different maturational stages of normal progenitor cells committed to the myeloid lineage with different orders of sensitivity. Blast-type colonies derived from patients with acute myelogenous leukemia were more sensitive to TNF alpha inhibition than progenitor cells purified from normal bone marrow or bone marrow from patients with stable-phase chronic myelogenous leukemia. The response of most colony types to IFN gamma was poor. However, when IFN gamma was administered together with TNF alpha, synergistically enhanced antiproliferative effects were detected in all colony types tested. The antiproliferative action of IFN gamma on myelopoiesis was enhanced in culture by the presence of autologous monocytes, presumedly by inducing endogenous production of TNF alpha. However, TNF alpha seemed to act directly on the progenitor cells themselves to suppress their clonal growth, rather than involving accessory marrow elements such as monocytes and/or T lymphocytes.