The use of cultured bone marrow cells for autologous transplantation in patients with acute myeloblastic leukemia.
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Biomedical subjects
Publications and source records attributed to N G Testa.
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The sensitivity of stromal progenitor cells (CFU-F) in mouse marrow to whole-body 60Co gamma-irradiation delivered at 0.65 Gy per day, was characterised by a D0 value of about 2.5 Gy up to an accumulated dose of 5 Gy. The cells were less sensitive to higher doses. The rate of recovery following irradiation for 14 days (9.1 Gy) was less than the rate after 30 days irradiation (19.5 Gy). The latter rate of recovery approached that of the stem cells (CFU-S). At 9-10 months after either dose of irradiation, recovery of both CFU-F and CFU-S was incomplete at 30-70% of the aged control.
Carmustine has been in clinical use since the 1960s and has proved efficacious in many treatment protocols. It has, however, been limited in its applications because of delayed hematopoietic toxicity which results in curtailment of treatment. A new derivative based on taurine, 1-(2-chloroethyl)-3-/2-(dimethylaminosulfonyl)ethyl-1-nitrosourea, has been developed and we have investigated its effects with a view to assessing the possibility of its being a causative agent for long-term marrow damage. We have found that while this new compound is less hematoxic than carmustine, it still demonstrates significant residual impairment of blood cell formation after application to mice. This impairment is noted in the CFU-S (stem cell) numbers and in the microenvironmental populations responsible for forming an ectopic site of hemopoiesis, persists for at least 180 days after the cessation of treatment, and may therefore be considered irreversible.
In long-term cultures of bone marrow from a patient with acute myeloblastic leukaemia (AML) the leukaemic chromosome marker, which was present in a proportion of the marrow cells even during morphological remission, was not detectable after seven days of culture. After florid relapse of AML, large-scale bone marrow cultures were established while the patient received conditioning with cyclophosphamide and total body irradiation as for an allogeneic bone marrow transplant. Marrow cultured for ten days was reinfused and three and six months later the patient was in clinical remission with a normal karyotype.
Following repeated treatment of mice with cyclophosphamide (5 X 200 mg/kg) it was found that slight, but significant, residual marrow damage persisted for at least half the lifespan of the animals. This long-term damage occurred despite preferential sparing of those multi-potential haematopoietic cells (CFU-S) that had a high self-renewal capacity after each step of the multistep regimen and despite a smaller CFU-S kill after each successive dose. The damage was characterized by low mean numbers of CFU-S and stromal colony-forming cells (CFU-F) which were around 70% of control values. Examination of individual animals revealed that the majority had slightly subnormal numbers of CFU-S and CFU-F, with only a few suffering a more severe injury, including 8% of mice with clinical hypoplasia or myelodysplasia.
Haemopoietic status and functions have been compared in young (2-3-month-old) and old (2-2.5-year-old) BDF1 mice. The parameters measured include total marrow cellularity, CFU-S, CFU-mix, GM-CFC, BFU-E and CFU-F. In all cases the numbers of these cells in the femoral marrow of the old mice was equal to or greater than those in the femoral marrow of young mice. In addition to these parameters we have compared the ability of marrow from young and old mice to repopulate the marrow of recipient mice whose marrow had been eliminated by radiation; to grow in long-term bone marrow cultures; to produce ectopic grafts of marrow beneath the renal capsule of normal recipients; and to supply inhibitor and stimulator of stem cell proliferation in the marrow and to resynthesise these substances. We could detect no differences in any of these functions with the exception of that of resynthesis of the stem cell regulator substances, which appears to be somewhat slower in the old mice. This, however, does not impose any limitation upon the ability of the marrow to function either under normal conditions or in conditions requiring rapid proliferation. Therefore we can find no evidence whatsoever to suggest that aging of the haemopoietic system plays any part in aging of the individual or influencing the life-span.
The effect of a highly purified human gamma IFN (r-gamma-IFN) on the growth of haemopoietic progenitors was examined in soft agar assays and in long-term bone marrow cultures. r-gamma-IFN reduced colony formation by progenitor cells of the granulocyte/macrophage lineage (GM-CFC), the erythroid lineage (BFU-E) and multipotent cells (GEMM-CFC), and suppressed haemopoiesis in long-term culture in a dose-related fashion. At high doses (1000 units/ml) r-gamma-IFN appeared to be toxic to the stromal cells of the bone marrow.
Interleukin-3 is a murine haemopoietic cell growth factor which has now been prepared in recombinant form, rIL-3. This purified material has been shown to act, in vitro, in a comparable manner to the native material and has recently been shown to have an in vivo effect on the committed, in vitro colony-forming cells. We have examined the effects, in vivo, of low acute and chronic infusion doses on the pluripotent haemopoietic spleen colony-forming cells, CFU-S, (stem cells). The proliferation rate of CFU-S is rapidly increased after administration of rIL-3. This is followed by a migration of the more mature CFU-S to the spleen where, particularly under chronic rIL-3 treatment there is a large increase in CFU-S numbers. The increased proliferation of CFU-S is accompanied by increased differentiation in the form of a large increase in in vitro IL-3 responsive cells. The changes observed were not the result of endotoxin contamination in the rIL-3 preparation. Significantly, however, larger doses of lipopolysaccharide, did mimic the effects of rIL-3 in vivo. IL-3 was not detected in the blood following LPs treatment but it is suggested that LPS acts indirectly on haemopoietic precursor cells by eliciting local production of IL-3, perhaps from adjacent T cells or stromal cells.
Persistent reductions in the femoral content of hemopoietic colony-forming cells (CFU-S and GM-CFC) were observed after four doses of irradiation, delivered with three weeks between doses. In general, the reductions were dose dependent, and similar reductions were produced by single doses and repeated doses using the same total dose. After the lowest doses investigated, 4 X 0.75 Gy 300-kVp x-rays or 4 X 0.38 Gy 14.7-MeV neutrons, the recovered levels remained at 60%-80% of control for at least one year after irradiation. The relative biological effectiveness (RBE) of neutrons is about 2 for these long-term hemopoietic deficiencies.
To investigate the persistence of spleen colonies from day 8 to day 11 of their development, we injected low numbers of marrow cells in order to obtain single colonies on the spleens of irradiated mice. Colonies were isolated on either half of the spleen on the eighth day. The position of day-11 colonies, determined relative to the ligature, indicated where novel colonies appear between those times. The results showed no evidence of the persistence of colonies from day 8 to day 11. The self-reproduction capacity of CFU-S that survive various cytotoxic drugs depends on the specific subpopulations that are affected by the drug. Using cyclophosphamide, busulphan, or BCNU, the self-renewal capacity of surviving CFU-S was manipulated. The results show that after cytotoxic treatments, a high day-11-day-8 ratio is not necessarily a reflection of a high self-renewal capacity of the CFU-S population that forms the day-11 colonies.
The effects of the cytotoxin busulphan (myleran) have been investigated in order to ascertain the unique nature of the lesion which it induces. It is one of only few compounds which can cause marked residual marrow dysfunction and the only drug reported to induce a marrow lesion of such magnitude that after a prolonged interval mice may die of the effects of pancytopaenia resulting from hypoplastic marrow failure. We have found that busulphan has a major microenvironmental effect as assessed by the ability of the marrow to form a complete organ in an ectopic site, which confirms existing evidence from a range of putative stromal assays. The effects upon CFU-S are known to include a selective action against certain subpopulations. Our investigation of the dose relationship of busulphan effects have shown that induction of the prolonged marrow lesion is not dependent on the dose of drug administered, or the fractionation regime employed, and is not dependent therefore on the number of CFU-S removed by the drug. The unique action of busulphan probably rests therefore in its ability to damage the microenvironment and the most primitive stem cells which are closely associated with it, if not entirely dependent on it, for their existence.
Stromal progenitor cells (CFU-F) in normal mouse bone marrow were more sensitive to heat at 43 degrees C than haemopoietic progenitor cells (CFU-S and GM-CFC) by a factor of approximately 1.2. In marrow regenerating after 4.5 Gy X-rays, the changes in sensitivity were by less than a factor of 1.4 and the sensitivity of CFU-F changed slightly to become intermediate between that of CFU-S and GM-CFC. A comparison of sensitivities reported in the literature revealed an inexplicable large variation of up to a factor of 6 in the thermal sensitivities of CFU-S and GM-CFC.
A patient is described who has had a marked eosinophilia of unknown cause for 9 years in association with episodic facial swelling. Weekly blood counts for 8 months showed cyclical variations in eosinophils, neutrophils and monocytes (mean cycle length 35 d). Marrow culture studies showed fluctuation in the incidence of granulocyte-macrophage colonies (GM-CFC), and the proportion of eosinophil colonies was higher than the values reported for normals. The blood lymphocyte T4/T8 ratio was reversed, due to an increase of T8+ cells. It is suggested that this condition is a rare form of periodic haemopoiesis.
The range of specificity of the CFU-S proliferation inhibitor and stimulator which are produced endogenously in the bone marrow has been investigated by measuring their effects on the proportion of cells killed by tritiated thymidine in mixed colony- (CFC-mix), erythroid burst- (BFU-E) and granulocyte/macrophage colony- (GM-CFC) forming cells as well as spleen colony forming units (CFU-S). Both CFU-S and CFC-mix were triggered by the stimulator into DNA-synthesis but BFU-E and GM-CFC were unaffected. The range of activity of the inhibitor was confined solely to the CFU-S population. This defined the specificity of both inhibitor and stimulator for the multipotent cells. The differential sensitivity of CFU-S and CFC-mix to the inhibitor and the lack of it for the stimulator suggested (a) that the CFC-mix is a relatively mature subpopulation of the CFU-S compartment and (b) that the relative sensitivity of a CFU-S to these factors changes as it matures from the early stem cell stage (Inhibitor-sensitive) to the more mature stages (Stimulator-sensitive) before becoming committed to a specific line of differentiation. The specificity of the inhibitor for haemopoietic stem cells suggests its potential value during chemotherapeutic procedures.
The Do value for fibroblastoid colony-forming units in mouse bone-marrow increased from 1.7 Gy using gamma-rays at 4.2 Gy/minute, to 2.6 Gy at 4.5 cGy/minute. In contrast, the sensitivity of bone-marrow stem cells was very little changed (Do approximately equal to 0.9 Gy). At 7.5 Gy acute single dose, the dose sparing achieved for CFU-F using 4.5 cGy/minute was a factor of 1.4, in between the values reported for lung of 1.8 and for haemopoiesis of 1.2. Although the role of CFU-F in the haemopoietic environment has not been established, the content of CFU-F can predict the ability of irradiated marrow to sustain haemopoiesis in the long term. Hence the data imply that the haemopoietic environment, as well as the dose-limiting lung, benefits from the use of low dose-rates for haemopoietic ablations in the treatment of leukaemia. No significant further sparing of CFU-F was achieved using a lower dose-rate of 1.4 cGy per minute.
The generation of osteoclasts in cultures of cat bone marrow was completely inhibited for 4 weeks with 10(-6)M hydrocortisone (HC) and partially inhibited with 10(-7) to 10(-9)M in a dose-dependent fashion. This effect was completely reversible when cultures were exposed for only 2 weeks to 10(-9) or 10(-8)M HC. However, cultures in which higher concentrations (10(-7) to 10(-5)M) were maintained for the same period did not show complete recovery in terms of numbers of osteoclasts and number of nuclei per cell after withdrawal of HC, suggesting that precursor cells of osteoclasts were also damaged by HC. To study the effects of HC on osteoclasts already present in the cultures, 10(-6)M was added to 4-week-old untreated cultures. The number of osteoclasts decreased rapidly and a gross morphological response was also apparent (rounding of the cells leading to detachment from the substratum and inhibition of cell fusion), indicating that the generation as well as the survival of osteoclasts in vitro are sensitive to HC. The morphological changes observed under optical and electron microscopy correspond to those of the reported inactive form of osteoclasts, and suggest that their function may also be altered by HC.
The GM-CFC assay for granulocyte-macrophage progenitors and the BFU-E and CFU-E assay for early and late erythroid progenitors from cat bone marrow were characterized. GM-CFC gave 59 +/- 4 to 118 +/- 6 colonies per 10(5) bone marrow cells using colony stimulating factors (CSF) from cat, mouse or human sources. The CFU-E and BFU-E assays gave 114 +/- 7 and 58 +/- 7 colonies respectively with optimum doses of erythropoietin. Irradiated cat bone marrow cells were good sources of CSF and of burst promoting activity for these assays. Kittens infected with feline leukaemia virus, subgroup C (FeLV-C), which induces pure red cell hypoplasia, showed the incidence of BFU-E decreased to 25-35% of controls as early as one week postinfection, and even lower values at later times. In contrast, the incidence of GM-CFC remained normal for several weeks. No evidence of inhibitory cells or of lack of stimulatory cells in the infected marrows was seen when they were cultured together with normal marrow in the BFU-E assay. Conversely, normal marrow cells were not able to restore BFU-E growth from infected marrow. This suggests a direct action of FeLV-C on early erythroid precursors. Infection with FeLV, subgroup A, which induces only a mild transitory anaemia, produces only a moderate decrease in the incidence of BFU-E.
A sub-optimal plateau in numbers of femoral stem-cells (CFU-S) in mice after 4 doses of 4.5 Gray X rays (each separated by 21 days), was shown to persist at 20-30% of control up to 1 year after the last dose, when about 50% of the mice had survived. The concentration of white cells in the blood was maintained persistently at about 70% of control, whereas the concentration of red cells was normal up to 4 months and then it declined to about 75% of control at 10 months after irradiation. Concentrations of some committed progenitor cells in the marrow (GM-CFC and ERC), which are capable of amplification cell divisions, were intermediate between the concentrations of marrow stem cells and mature blood cells in both the granuloid and the erythroid cell lineages, respectively. Hence increased amplification was a mechanism operating for a prolonged period in the production of numbers of mature cells. The numbers were subnormal, however, and this corresponded to only 1 extra amplification division on average. There was a slow decline after 6 months in the numbers of CFU-S, BFU-E and GM-CFC, and in the hematocrit, with reference to age-matched controls. The decline was due partly to a prevention of the natural increase in cell numbers in the marrow with the age of the mice, which was also seen with the femoral content of a stromal progenitor cell (CFU-F). A defect in the repeatedly-irradiated CFU-S population was detected as a persistent inability to produce colonies containing the same number of daughter CFU-S as contained in colonies derived from unirradiated marrow and assayed at the same time.