Angiogenic Molecules and Inflammatory Cytokines in Patients with Thalassemia Major and Double Heterozygous HbS/Beta-Thalassemia; the impact of Deferasirox.

Abstract 2018

Poster Board I-1040

Angiogenesis is a crucial process in the pathogenesis of several inflammatory, autoimmune and malignant diseases. Endothelial damage and inflammation make a significant contribution to the pathophysiology of sickle cell disease (SCD) and the beta-thalassemia syndromes. However, there are very limited data in the literature for the role of angiogenic cytokines in the pathogenesis of thalassemia major (TM) and of double heterozygocity of SCD and beta-thalassemia (HbS/beta-thal). Deferasirox (Exjade®) is a once-daily orally administered iron chelator approved for the treatment of transfusional iron overload in patients with transfusion-dependent anemia which seems to reduce markers of inflammation in TM. The aim of this prospective study was to evaluate the levels of angiogenic and inflammatory cytokines in patients with TM and HbS/beta-thal with iron overload who received chelation therapy with deferasirox. Forty-five patients (16M/29F) with TM and 20 patients (7M/13F) with HbS/beta-thal were evaluated. Deferasirox was administered at a dose between 10-30 mg/kg/day based on the number of blood transfusions received before the initiation of treatment. After 3 months, dose adjustments (increases) were allowed in increments of 5 mg/kg/day every 3 months as required to reduce markers of iron overload. Deferasirox was given for a period of 12 months. Serum levels of angiogenic cytokines, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), angiogenin (Ang), angiopoietin (Angp)-1 and -2 and of inflammatory cytokines including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-á), IL-1á, IL-1β, IL-4, IL-10 and transforming growth factor (TGF)-β1 and β2, were measured at baseline (day 1 of deferasirox administration) and then after 12 months post-deferasirox therapy, using ELISA methodology (R&D Systems, Minneapolis, MN, USA, for angiogenin cytokines and ILs and Diaclone, Bensancon, France for TNF-á, TGF-β1 and TGF-β2). Twenty healthy blood donors of similar age and gender were also evaluated as control group. Standard hematology and biochemistry was evaluated monthly in all patients. Patients with both TM and HbS/beta-thal had increased levels of all studied angiogenic cytokines compared with healthy controls but reduced levels of Angp-1/Angp-2 ratio (p<0.01 for all comparisons). Patients with HbS/beta-thal had increased levels of Angp-2 (p=0.002) and reduced levels of Angp-1/Angp-2 ratio (p<0.001) compared to TM patients. Both TM and HbS/beta-thal patients had also increased levels of IL-6 (p=0.008), IL-1á (p=0.01), TGF-β2 (p=0.01), IL-10 (p=0.02), IL-4 (p=0.03), and TNF-á (p=0.01) compared to controls. There were no differences between TM and HbS/beta-thal patients in terms of inflammatory cytokines. In TM patients, VEGF strongly correlated with TGF-β1 (r=0.652, p<0.001), platelet count (r=0.503, p=0.001) and white blood cell (WBC) count (r=0.484, p=0.002), while Angp-2 strongly correlated with TNF-á (r=0.536, p=0.001), WBC count (r=0.430, p=0.008) and platelet count (r=0.330, p=0.01). In HbS/beta-thal patients Angp-1/Angp-2 ratio strongly correlated with ALT (r=-0.611, p=0.007) and Hb (r=0.498, p=0.036). Twelve months post-deferasirox administration, there was a dramatic reduction of ferritin, SGOT and SGPT compared with baseline values in both patient groups (p<0.0001). TM patients showed a continuous increase of both VEGF (mean±SD: from 680±489 ng/ml prior to deferasirox to 801±547 ng/ml post-deferasirox; p=0.002) and bFGF (from 16.2±17.1 ng/ml prior to deferasirox to 33.1±28.8 ng/ml post-deferasirox; p=0.001) after 12 months of deferasirox therapy. No other changes were observed in TM group regarding angiogenic molecules. Patients of HbS/beta-thal showed no alterations in terms of angiogenic cytokines that continued to be elevated compared to controls. In terms of inflammatory cytokines deferasirox produced a reduction of TNF-á in both studied groups (p<0.01 for all comparisons). Our study suggests that angiogenic and inflammatory cytokines are increased in patients with TM and HbS/beta-thal and thus they have a role in the pathogenesis of these disorders. Angiopoietins seem to be strongly implicated in the biology mainly of HbS/beta-thal. However, further studies are needed to fully elucidate this role as well as the effect of deferasirox, if any, on inflammation. Deferasirox seems to have no impact on angiogenic cytokines.