Oxidative Stress Levels Are Correlated with Disease Progression and Iron Overload in MDS Patients with Excess Blasts
Authors: Shimizu Naomi , Watanabe Yasuhiro , Ban Noriko , Yamaguchi Takashi , Hasunuma Hidekazu , Iwashita Youichi , Yokota Hiromitsu , Nakaseko Chiaki , Bujo Hideaki , Tatsuno Ichiro 
Published: October 2019

Abstract
Introduction : Oxidative stress is closely related to iron overload in myelodysplastic syndrome (MDS) and induces DNA damage. A recent study has suggested that oxidative stress leads to increased mutation frequency in a murine model of MDS, and that additional mutations lead to the progression of MDS. We have recently reported that oxidative stress marker reflects not only iron overload but also disease progression in a MDS patient (2016, Shimizu et al). So there is a possibility that the increase in oxidative stress markers may have not only caused the iron overload but also resulted in the disease progression of MDS. To clarify this point, we evaluated the association among oxidative stress marker and disease progression in eight patients with MDS. In this study, we first examined the oxidative stress marker, derivatives of reactive oxygen metabolite (dROM), ferritin in serum and Wilms Tumor 1 gene (WT1) in the peripheral blood throughout the course of treatment. Then, we analyzed the correlations of the levels of dROM, ferritin and WT1. Next, we investigated ROS expression in each fraction of WBC by flow cytometry in a healthy donor and some MDS patients.
Materials and methods: Levels of serum dROM were measured by colorimetry, using samples of MDS (RA n=3, RAEB-1 n=4, RAEB-2 n=1). Ferritin in serum and WT1 in peripheral blood were also measured. Statistical analyses were performed by Pearsonfs test. The ROS expression was evaluated during the clinical course by flow cytometry.
Results: Table 1 shows the relationship between dROM, ferritin and WT1 in MDS patients throughout the treatment. Case 1 to 3 patients showed disease progression with excess blasts in spite of azacitidine treatment. These patients showed a correlation tendency between dROM and ferritin, dROM and WT1. Case 1 showed close relationship between ferritin and WT1. Case 3 shows slight relation between ferritin and WT1. Case 4 to 8 patients showed no disease progression. They were treated with supportive therapy, including blood transfusion or cytokine therapy. These patients showed no relation between dROM and the elevation of ferritin and WT1. In these patients, there was no relation between ferritin and WT1 except Case 6. We also evaluated the score of WPSS, IPSS and dROM at diagnosis. dROM did not correlate with WPSS and IPSS. Figure 1 shows increased ROS expression during disease progression in a MDS patient compared with healthy control. Considering that other MDS patients with excess blasts showed the similar pattern, the present result suggested that the oxidative stress markers were produced by tumor-derived cells.
Conclusions: dROM levels were slightly related with the ferritin and WT1 mRNA expression levels in MDS patients with excess blasts. We speculate that the increase in the oxidative stress markers is a cause of not only iron overload but also the disease progression of MDS. Oxidative stress markers may contribute to evaluate the progression of treatment efficacy for MDS patients.
Table 1 Patientfs characteristics and correlation between serum dROM and ferritin, WT1 mRNA in MDS patients. Table 1. Patientfs characteristics and correlation between serum dROM and ferritin, WT1 mRNA in MDS patients. Figure 1 The increment of ROS expression during disease progression in a MDS patient with excess blasts. Figure 1. The increment of ROS expression during disease progression in a MDS patient with excess blasts.

Disclosures
Nakaseko: BMS: Honoraria, Research Funding; PFIZER: Honoraria, Research Funding; NOVARTIS: Honoraria.