Busulphan Conditioning Research Articles

Vitamin D Relation to Busulphan in Pediatrics Undergoing Hematopoietic Stem Cell Transplantation

Vitamin D is an essential compound that plays an important role in biological activities. There are two main sources of vitamin D: either through the conversion of 7-dehydrocholesterol in the skin by UVB light or through absorption in the small intestine via food intake or dietary supplements. Vitamin D from both sources undergoes a first hydroxylation in the liver through cytochrome P 450 forming 25 (OH) vitamin D, followed by a second hydroxylation that takes place in the kidneys resulting in the active form of the vitamin D (1.25 (OH)2 Vitamin D). Busulphan is an alkylating agent used mainly as part of the myeloablative conditioning prior to hematopoietic stem cell transplantation (HSCT). Recent studies have shown that vitamin D can have some interaction (additive, synergistic, or antagonistic) with a number of chemotherapeutic agents; therefore, we have investigated the relation between vitamin D and busulphan.In the present investigation, the relation between vitamin D and busulphan was evaluated in 44 pediatric patients undergoing stem cell transplantation. The patients received busulphan (1.8-2mg/kg twice a day for four days) as a prat of their condition regimen prior to HSCT. Patients were divided into two groups; the first group received the drug orally (n=20) while the second was treated intravenously (n=24). Blood samples were collected from these patients, and busulphan was quantified in the plasma using gas chromatography with electron capture detector, while 25 (OH) Vitamin D levels were measured using ELISA.Our results showed that the levels of vitamin D before the start of the conditioning were positively correlated with the first busulphan AUC in the group of patients receiving the drug orally (R2=0.25, P<0.05). Moreover, a significant (p<0.0001) increase was observed in the plasma levels of vitamin D (290 -1190 ng/mL) at 24h after the start of busulphan conditioning compared to that found before the start of busulphan treatment (15-162 ng/mL).On the other hand, no significant changes in the vitamin D levels were observed in the patients receiving busulphan intravenously. To confirm the previous findings, two groups of mice were treated with busulphan (25mg/Kg/day) dissolved in 5% DMSO either orally (PO) or intraperitoneally (IP) once daily for 4 days. Mice were fed with standard chew (Teklad Global 18% Protein Rodent Diet containing vitamin D3 at a concentration of 1.5 IU/g) and food intake was monitored daily. Two control groups (received oral 5% DMSO or intraperitoneal 5% DMSO and negative controls) were run in parallel. Vitamin D levels were measured in mice plasma using ELISA. The results showed that vitamin D levels were higher in mice treated with oral busulphan compared to those who received the drug via IP administration.In conclusion, the present results indicate that vitamin D levels before conditioning may influence busulphan AUC when the drug is administered orally and hence the clinical outcome. On the other hand, the oral administration of busulphan has a significant effect on the vitamin D levels, which suggest that the observed effects are mainly based on alteration in vitamin D uptake. Currently, further studies are ongoing to investigate the underlying mechanisms. Altogether, suggest that busulfan levels and vitamin D intake should be monitored in patients treated with oral busulphan in order to avoid their toxicities and improve the clinical outcome. DisclosuresNo relevant conflicts of interest to declare.

Late effects after allogeneic hematopoietic cell transplantation with busulphan conditioning in 33 childhood leukemia survivors (1987-2013)

Late effects after allogeneic hematopoietic cell transplantation with busulphan conditioning in 33 childhood leukemia survivors (1987-2013)

A clinical analysis of hepatic veno-occlusive disease after hematopoietic stem cell transplantation

Objective: To analyze the outcome and the prognostic factors of hepatic veno-occlusive disease (HVOD) after hematopoietic stem cell transplantation (HSCT). Methods: A total of 797 patients receiving HSCT were analyzed retrospectively. The prophylaxis regimen of HVOD in the First Affiliated Hospital of Guangxi Medical University consisted of low molecular weight heparin and lipoprostaglandin E1 (PGE1). Results: Fifty-nine patients (7.4%) developed HVOD at 3-49 days after HSCT (median 12 days). Age younger than 15 years at transplant(HR= 6.47, P<0.001), busulphan conditioning (HR=6.40, P<0.001), thalassemia major (HR=6.35, P<0.001), allogeneic transplantation (HR=7.74, P=0.005) were univariate risk factors for HVOD. Multivariate analyses suggested that thalassemia major and busulphan conditioning were independently correlated with the development of HVOD. Conclusion: Thalassemia major and busulphan conditioning are independent risk factors for HVOD after HSCT.

The effect of N-acetyl-l-cysteine (NAC) on liver toxicity and clinical outcome after hematopoietic stem cell transplantation

Busulphan (Bu) is a myeloablative drug used for conditioning prior to hematopoietic stem cell transplantation. Bu is predominantly metabolized through glutathione conjugation, a reaction that consumes the hepatic glutathione. N-acetyl-l-cysteine (NAC) is a glutathione precursor used in the treatment of acetaminophen hepatotoxicity. NAC does not interfere with the busulphan myeloablative effect. We investigated the effect of NAC concomitant treatment during busulphan conditioning on the liver enzymes as well as the clinical outcome. Prophylactic NAC treatment was given to 54 patients upon the start of busulphan conditioning. These patients were compared with 54 historical matched controls who did not receive NAC treatment. In patients treated with NAC, aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) were significantly (P < 0.05) decreased after conditioning compared to their start values. Within the NAC-group, liver enzymes were normalized in those patients (30%) who had significantly high start values. No significant decrease in enzyme levels was observed in the control group. Furthermore, NAC affected neither Bu kinetics nor clinical outcome (sinusoidal obstruction syndrome incidence, graft-versus-host disease and/or graft failure). In conclusion: NAC is a potential prophylactic treatment for hepatotoxicity during busulphan conditioning. NAC therapy did not alter busulphan kinetics or affect clinical outcome.

Enhancing epithelial engraftment of rat mesenchymal stem cells restores epithelial barrier integrity

The cellular origin, in vivo function and fate of donor bone marrow-derived cells residing in the recipient intestinal epithelial cells, pericryptal myofibroblasts or endothelial cells remain obscure. Although 'immunoprivileged' mesenchymal stem cells (MSCs) are prime candidates for cell- and gene-based therapy, their precise role in colitis remains largely undetermined. Using a dextran sulphate sodium (DSS) colitis with busulphan (BU)-induced hypoplastic marrow model, we examined the therapeutic effects of MSC transplantation, focusing on the role of MSCs as both cell providers and immunomodulators. Donor-derived MSCs were detected by eGFP immunofluorescence and fluorescence in situ hybridization for Y-chromosome (Y-FISH) analysis. Western blot analysis of apical-most tight junction proteins was performed with antibodies against claudin-2, -7, -8, -12, -13, -15 and ZO-1. Cytokine and cell cycle profiles were analysed by semi-quantitative RT-PCR and flow cytometry. Susceptibility to DSS colitis was significantly increased by co-existing BU-induced bone marrow hypoplasia and this increase was significantly reduced by enhancing epithelial engraftment of MSCs, an effect depending on restoring epithelial barrier integrity rather than inhibiting host immune responses. We provide evidence that implicates MSCs in maintaining epithelial barrier function by reassembling apical-most tight junction proteins, claudins. The therapeutic efficacy of extrinsic MSCs depends on enhancing epithelial engraftment in damaged crypts by busulphan conditioning. Such a role for the MSC-derived intestinal cells in colitis therapy merits further examination and may offer a promising new treatment for inflammatory bowel disease (IBD).

Low-dose busulphan conditioning and neonatal stem cell transplantation preserves vision and restores hematopoiesis in severe murine osteopetrosis

Infantile malignant osteopetrosis is a fatal disease caused by lack of functional osteoclasts. In most of patients, TCIRG1, encoding a subunit of a proton pump essential for bone resorption, is mutated. Osteopetrosis leads to bone marrow failure and blindness due to optic nerve compression. Oc/oc mice have a deletion in Tcirg1 and die around 3 to 4 weeks, but can be rescued by neonatal stem cell transplantation (SCT) after irradiation conditioning. However, as irradiation of neonatal mice results in retinal degeneration, we wanted to investigate whether conditioning with busulphan prior to SCT can lead to preservation of vision and reversal of osteopetrosis in the oc/oc mouse model. Pregnant dams were conditioned with busulphan and their litters transplanted with 1 x 10(6) normal lineage-depleted bone marrow cells intravenously or intraperitoneally. Mice were followed in terms of survival and engraftment level, as well as with peripheral blood lineage analysis, bone and eye histopathology and a visual-tracking drum test to assess vision. Busulphan at 15 mg/kg was toxic to oc/oc mice. However, six of seven oc/oc mice conditioned with busulphan 7.5 mg/kg survived past the normal lifespan with 10% engraftment, correction of the skeletal phenotype, and normalization of peripheral blood lineages. Busulphan, in contrast to irradiation, did not have adverse effects on the retina as determined by histopathology, and 8 weeks after transplantation control and oc/oc mice retained their vision. Low-dose busulphan conditioning and neonatal SCT leads to prolonged survival of oc/oc mice, reverses osteopetrosis and prevents blindness even at low engraftment levels.

The modification of high-dose therapy shortens the duration of neutropaenia by delay of leucocyte nadir

Infections during neutropaenia contribute still significantly to mortality and morbidity after high-dose therapy and autologous stem cell transplantation. Further acceleration of haemopoietic recovery seems impossible for biological reasons. Another approach to shorten neutropaenia could be to remove drugs from high-dose therapy protocols with strong contribution to immunosuppression and neutropaenia and unproven antineoplastic activity. In this retrospective matched-pair analysis, conventional busulphan/cyclophosphamide (Bu/Cy) high-dose therapy was compared to single-agent busulphan conditioning before autologous stem cell transplantation. This modification led to a significant shorter neutropaenic interval by protraction of cell decrease and to a significant mitigation of neutropaenia. After single-agent busulphan conditioning, leucocytes dropped below 1/nl at median 1.5 days later when compared to the patients from the busulphanBu/Cy control group (P=0.001). In a significant percentage of patients (n=6, 60%) leucocytes did not fall below 0.5 cells/nl at any time. In contrast, all patients from the Bu/Cy control group experienced deep neutropaenia (P=0.004). Thrombocytopaenia and requirement for transfusions of platelets or red cells were not influenced. Antineoplastic activity seemed to be preserved as determined by survival analysis. In conclusion, modification of high-dose regimen with the intention to shorten neutropaenia with preserved antitumour activity could be an approach to reduce infection-related morbidity and mortality and to consider economic necessities.

Autologous Peripheral Blood Stem Cell Transplantation in First Remission Adult Acute Myeloid Leukaemia--An Intention to Treat Analysis and Comparison of Outcome Using a Predictive Model Based on the MRC AML10 Cohort

The role of autologous peripheral blood stem cell transplantation (APBSCT) in acute myeloid leukaemia (AML) remains controversial. The current study evaluated the application of APBSCT in a large consecutive series of patients with untreated AML, and compared outcome with a predictive model based on MRC AML10 data. Of 148 evaluable patients, 118 patients entered complete remission (CR) after induction therapy comprising three cycles of daunorubicin, cytosine arabinoside and oral 6-thioguanine. Of these patients, 68 (57%) proceeded to consolidation therapy with two courses of intermediate dose cytosine arabinoside, and stem cell mobilisation, and 40 of these patients (34%) underwent the APBSCT procedure after high dose busulphan conditioning. Harvest quality was the main factor precluding APBSCT. Five-year event-free survival (EFS) in patients who achieved CR was 38% and in APBSCT patients was 57%. There were no transplant-related deaths. No significant differences were demonstrated between observed and expected outcomes at 1 and 2 years, based on the predictive model derived from the MRC AML10 study. These data therefore indicate that only a third of eligible adult patients will undergo APBSCT. However, the results demonstrate favourable survival in such patients, with no transplant-related mortality.

Haemorrhagic cystitis: incidence and risk factors in a transplant population using hyperhydration.

Haemorrhagic cystitis (HC) is the syndrome of haematuria and symptoms of lower urinary tract irritability in the absence of bacterial infection. We report a low incidence of HC (18.2%) in 681 haemopoietic stem cell transplant patients, using a prophylactic regimen of hyperhydration and forced diuresis. The incidence of grade 3-4 disease is 3.4%. There was a marked difference in incidence between allogeneic and autologous transplant populations, 24.2% vs. 3.5% (P<0.0005). Busulphan conditioning, acute GVHD, interstitial pneumonitis and use of methotrexate and cyclosporin immune suppression were associated with significantly increased incidence of HC in the allogeneic population. This may reflect the numerous factors that contribute to the greater immunosuppression and consequent increased risk for HC in allogeneic transplantation.