Sequential changes in serum iron and ferritin in patients undergoing high-dose chemotherapy and radiation with autologous bone marrow transplantation: possible implications for treatment related toxicity

Iron overload might increase transplant-related mortality in haematopoietic stem cell transplantation

Iron overload (IO) is associated with free radical generation and tissue damage. Our main objective was to ascertain if very high levels (VHL) of ferritin (>/=3000 microg/l) and transferrin saturation (TS) >/=100% during conditioning had an impact on overall survival (OS) and transplant-related mortality (TRM) after a haematopoietic stem cell transplantation (HSCT). Levels of ferritin and TS were measured at days -7 and -4, respectively, in 25 patients who underwent HSCT after CY/TBI. The group consisted of 20 men and five women with a median age of 40 years. Fifteen patients were autotransplanted and 10 allotransplanted. Nine of them had a diagnosis of AL, six of CML and 10 of lymphoma. Thirteen of them were in early and 12 in advanced status of disease. VHL of ferritin and TS >/=100% were associated with a decreased OS (P = 0.001 and P = 0.006, respectively) and an increased TRM (P = 0.003 and P = 0.004, respectively) in univariate survival analysis. Both variables remained significant at multivariate analysis for OS (P = 0.03 and 0.02, respectively) and TS was an independent factor for TRM (P = 0.01). Ferritin was very close to achieving statistical significance for TRM (P = 0.06) in multivariate analysis. In conclusion, VHL of ferritin and TS >/=100% at conditioning are associated with an increase in toxic deaths after transplant.

Different onsets of oxidative damage to DNA and lipids in bone marrow and liver in rats given total body irradiation

We examined time-dependent changes in antioxidant vitamins and oxidative damage to DNA and lipids in the bone marrow, liver, and plasma of rats given total body irradiation (TBI) with X-rays at 3 Gy. The oxidative damage to DNA and lipids was evaluated by measuring increases of 8-hydroxydeoxyguanosine (8OHdG) in DNA and 4-hydroxy-2-nonenal (HNE), respectively. After the TBI, marked increases in 8OHdG and HNE were detected at 3 to 5 h in the bone marrow, while gradual increases in these parameters were detected after a few days in the liver. These changes in 8OHdG and HNE were well correlated within each tissue. In the bone marrow, levels of both vitamin C and vitamin E were decreased by the TBI; however, the changes in vitamin C were earlier and greater than those in vitamin E. In the liver, the level of vitamin C did not decrease, but that of vitamin E decreased due to the TBI. Changes in HNE, vitamin C, and vitamin E in the plasma were similar to those in the liver. Within each tissue, the time of decrease in antioxidants was almost the same as that of the increase in oxidative damage. An increase in total iron due to the TBI was also detected in these tissues. In particular, the total iron in the bone marrow was markedly increased at a few hours after the TBI, with a slight increase in transferrin and no increase in ferritin. Exposure studies performed on cells or isolated DNA showed that an increase in 8OHdG was detected immediately after irradiation at more than 100 Gy in bone marrow cells and at less than 10 Gy in isolated DNA, suggesting that an increase in 8OHdG is undetectable even in bone marrow immediately after the TBI at 3 Gy. These results indicate that the onset of oxidative damage to DNA and lipids was delayed after TBI at 3 Gy, that it was quite different in the bone marrow and the liver, and that an increase in iron and decrease in antioxidant vitamins were involved in the mechanism of oxidative damage.

Regulation of glutathione redox status in lung and liver by conditioning regimens and keratinocyte growth factor in murine allogeneic bone marrow transplantation

BACKGROUND

Reactive oxygen species (ROS) and glutathione (GSH) depletion contribute to organ injury after bone marrow transplantation (BMT). Keratinocyte growth factor (KGF) ameliorates graft-versus-host disease (GVHD)-associated organ injury in murine BMT models.

METHODS

B10.BR mice received total body irradiation (TBI; day -1) +/- cyclophosphamide (Cy; 120 mg/kg/day i.p., days -3 and -2), then were transplanted on day 0 with C57BL/6 bone marrow + spleen cells as a source of GVHD-causing T cells. KGF (5 mg/kg/day subcutaneously [s.c.]) or saline was given on days -6, -5, and -4. Lung and liver GSH and oxidized GSH disulfide (GSSG) levels were measured on days 0 and 5 and glutathione redox potential (Eh) calculated. Organ malondialdehyde (MDA) was determined on day 5 as an index of ROS-mediated lipid peroxidation.

RESULTS

In lung, TBI+BMT oxidized GSH Eh and increased MDA. Cy further oxidized lung GSH Eh. In liver, neither BMT regimen altered GSH redox status or MDA. KGF prevented the decrease in lung GSH after TBI+Cy and decreased lung MDA after both TBI and TBI+Cy. KGF increased liver GSH levels and GSH Eh after TBI and GSH Eh after TBI+Cy.

CONCLUSIONS

In murine allogeneic BMT, TBI oxidizes the lung GSH redox pool and Cy exacerbates this response by 5 days post-BMT. In contrast, liver GSH redox status is maintained under these experimental conditions. KGF treatment attenuates the Cy-induced decrease in lung GSH, decreases post-BMT lung lipid peroxidation, and improves liver GSH redox indices. KGF may have a therapeutic role to prevent or attenuate GSH depletion and ROS-mediated organ injury in BMT.

Non-transferrin-bound iron during allogeneic stem cell transplantation

Hydroxyl radical formation catalysed by non-transferrin-bound iron (NTBI) might contribute to transplantation-related complications. The occurrence of NTBI in 10 adult allogeneic stem cell transplantation (SCT) patients was followed for 20 d. The transferrin saturation reached 99% on d -4 and remained > 80% thereafter. NTBI, measured as bleomycin-detectable iron, was detected for 6-18 d in all patients with a peak on d -4. High transferrin saturation levels were associated with the appearance of NTBI with a threshold at 80% saturation. Prevention of the potential deleterious effects of NTBI might reduce transplantation-related morbidity.

Epirubicin-induced oxidative DNA damage and evidence for its repair in lymphocytes of cancer patients who are undergoing chemotherapy

Anthracycline derivatives have been widely used in the treatment of several types of human malignancies. Cytotoxicity of these drugs has been attributed to inhibition of topoisomerase II as well as intracellular production of free radicals. In our work we used a gas chromatography/mass spectrometry technique to study free radical-induced DNA base modifications in chromatin isolated from lymphocytes of cancer patients who received chemotherapy with epirubicin (one of anthracycline's antitumor derivatives). The anticancer therapy caused significant increases in the amount of all four DNA base modifications over control levels in the lymphocytes of most of the patients. For the majority of the cases the base products returned to the control value 24 hr after the infusion of the drug, which suggests the removal of these lesions by cellular repair processes. However, some of the modified bases escaped repair. Because part of these modifications may possess premutagenic properties, they may be responsible for secondary cancers induced by chemotherapy.

Nontransferrin-bound iron in serum of patients receiving bone marrow transplants

Nontransferrin-bound iron (NTBI) and other parameters of iron status were measured in 40 patients undergoing bone marrow transplantation (BMT) prior to conditioning therapy (between day -10 and -7), at the time of BMT (day 0), and 2 weeks later (day + 14). Serum iron and transferrin saturation values were normal before conditioning therapy. At day 0 serum iron values were high and median transferrin saturation was 98% (changes in the values of both serum iron and transferrin saturation, p < .0001). Transferrin saturation values were still elevated 2 weeks posttransplant (day +14 vs. baseline values, p = .0001). Starting at low NTBI levels pretransplant (median 0.4 micromol/l, range 0-4.2 micromol/l, controls: < or = 0.4 micromol/l), all patients revealed high levels on day 0 (median 4.0 micromol/l, range 1.9-6.9 micromol/l, p < .0001) and 2 weeks posttransplant (median 2.7 micromol/l, range 0-6.2 micromol/l, p < .0001). These observations indicate that the plasma iron pool in patients undergoing BMT increases to a level at which the normal ability to sequestrate iron becomes exhausted and considerable amounts of NTBI appear in serum. This "free" form of iron can mediate the production of reactive oxygen species and may cause organ toxicity in the early posttransplantation period.