The interplay among iron metabolism, endothelium and inflammatory cascade in dysmetabolic disorders

PURPOSE

Metabolic syndrome (MetS) is considered as a proinflammatory and prothrombotic state with atherogenic risk factors including dyslipidemia, obesity and glucose intolerance. Oxidative stress is a unifying basis of several disorders including diabetes mellitus (DM) and MetS. We therefore designed this cross-sectional study to investigate the potential interaction among iron metabolism, inflammation and endothelial plexus in MetS and DM patients.

METHODS

A total of 62 patients [median age 54 (23-76) years; male/female 16/46] and 18 healthy controls [median age 38 (30-64) years; male/female 6/12] were included in the study. Patient population was classified as MetS (n = 30) and DM (n = 32).

RESULTS

Leukocyte count (p = 0.002) and osteopontin (OPN) levels (p = 0.008) were significantly higher, while C-reactive protein (CRP) (p = 0.056) and IL-6 (p = 0.059) represented a relative increase in the patient group. Leptin, endothelin 1 (ET1), hepcidin, nitric oxide synthase (NOS), erythrocyte sedimentation rate (ESR), iron, transferrin saturation (TS) and ferritin levels were not significantly different between the patient and control groups. Endothelin 1 was found to be higher in the DM group compared to MetS group (p = 0.15, p = 0.049). Leukocyte count, leptin, hepcidin, OPN, NOS, IL-6, ESR, CRP, iron, TS and ferritin levels were not different between DM and MetS groups. A positive correlation was demonstrated between leptin and OPN (p = 0.001, r = 0.360), ferritin and hepcidin (p < 0.01, r = 0.633), IL-6 and CRP (p = 0.023, r = 0.319), leptin and NOS (p = 0.005, r = 0.309) and OPN and NOS (p < 0.001, r = 0.803). There was a negative correlation between hepcidin and NOS (p = 0.009, r = -0.289). When the study cohort was divided into two particular groups based on median ferritin and hepcidin levels, hepcidin (p = 0.002), ALT (p = 0.001) and LDL (p = 0.049) levels were higher in the high-ferritin group. Nitric oxide synthase levels (p = 0.033) were lower, whereas ferritin levels (p = 0.004) were higher in the high-hepcidin group.

CONCLUSION

Mechanisms involved in the vicious circle of MetS including inflammation, endothelial vasculature and iron metabolism remain to be elucidated. The role of iron metabolism in this complex interaction should be confirmed with further studies.

Iron overload: predictor of adverse outcome in hematopoietic stem cell transplantation

INTRODUCTION

Iron overload is an important problem in candidates for and survivors of hematopoietic stem cell transplantation (HSCT), and affects long-term outcome and survival. The objective of the present study was to determine the effect of iron overload on early toxic or infectious complications and survival.

PATIENTS AND METHODS

We retrospectively reviewed the medical records for 250 adult patients (162 men and 88 women; median [range] age, 34 [16-71] years who underwent HSCT between September 2003 and August 2008. The HSCT grafts were autologous in 102 patients, and allogeneic in 148.

RESULTS

Follow-up was 315 (1-1809) days. Mean (SD) pre-HSCT serum ferritin concentration was 1402.6 (5016.2) ng/mL in the entire group, 647.6 (1204.3 ng/mL in autologous recipients, and 1410.6 (2410.4) ng/mL in allogeneic recipients. Twenty-eight autologous graft recipients (27.4%) and 102 allogeneic recipients (68.9%) demonstrated serum ferritin concentrations of 500 ng/mL or greater, and were classified as the high-ferritin group. High ferritin concentrations were significantly associated with toxic or infectious complications including mucositis, fungal infections, pneumonia, and sinusoidal obstruction syndrome in the early post-HSCT setting. A significant effect of pre-HSCT ferritin concentration on overall survival and transplant-related mortality was observed. The effect of pre-HSCT ferritin on survival was independent of the comorbidity index at Cox regression analysis. In the entire study population, the probability of survival was significantly lower when ferritin concentration was greater than 500 ng/mL.

CONCLUSION

Transplant-related mortality has decreased substantially with the development of supportive treatments. Pretransplantation risk assessment and risk-adapted strategies such as decreasing iron overload might further improve transplant-related complications.

The impact of bone marrow fibrosis on the outcome of hematopoietic stem cell transplantation

We retrospectively analyzed the data of 175 patients who underwent autologous (n = 69) or allogeneic hematopoietic stem cell transplantation (HCT) (n = 106) including 19 (27.5%) and 38 (35.8%) recipients who had bone marrow fibrosis (BMF) prior to transplantation, respectively. We investigated the effects of BMF on engraftment, graft-versus-host disease (GVHD), early posttransplant complications, and survival. Pretransplantation BMF did not delay engraftment and showed no impact either on early posttransplant complications or on the development of acute and/or chronic GVHD. Probability of 1-year overall survival (OS) and progression-free survival (PFS) of autologous HCT recipients were similar, namely 76.7% versus 88.6% (P > .005) and 26.33% versus 16.5% (P > .05) among patients with versus without fibrosis, respectively. In allogeneic HCT recipients, the probability of 1-year OS was 35.2% among patients with versus 48.9% among those without fibrosis (P = .004) PFS at 1 year was inferior among allogeneic HCT recipients with BMF: 27.8% versus 51.2% (P = .0008). Cox regression analysis revealed BMF to be independently associated with age, Sorror comorbidity index, primary disease, and disease status during HCT (P = .045).

Impact of ABO-incompatible donor on early and late outcome of hematopoietic stem cell transplantation

ABO incompatibility is not a barrier to allogeneic hematopoietic stem cell transplantation (HSCT). However, the impact of an ABO mismatch on the outcome of the HSCT remains controversial. We analyzed whether ABO incompatibility leads to an increased risk of early/late complications, mortality, or increased transfusion requirements. The 147 consecutive allogeneic HSCTs includes 80 ABO-identical and 25 major, 30 minor, and 12 bidirectional ABO-mismatched grafts. The four groups were balanced with respect to disease status at transplantation. Transplantation-related mortality was significantly greater (P < .01) and overall survival significantly shorter (P = 0.2) among HSCT recipients with minor ABO-mismatched grafts. The relapse rate, progression-free survival, and transfusion requirements until discharge were not different between ABO-identical and ABO-mismatched groups. Pure red cell aplasia (PRCA); (P < .0001) and delayed red blood cell (RBC) engraftment (P < .001) were more frequent in HSCT recipients with major mismatched donors. Delayed RBC engraftment was associated with posttransplantation hyperferritininemia and increased mortality risk (P = .05). The greater frequency of sinusoidal obstruction syndrome and graft-versus-host disease (GVHD) in patients with minor mismatched transplants, did not show statistical significance. In contrast severe GVHD was significantly more frequent among minor mismatched patients (P = .04). ABO-mismatched HSCT might have an unfavorable impact on transplant outcomes. Selection of ABO-compatible donors when possible, strategies to prevent and treat PRCA, modifications in transfusion practice, and effective iron chelation are among the measures that can improve transplant outcomes.

Treatment of sinusoidal obstruction syndrome with defibrotide: a single-center experience

Sinusoidal obstruction syndrome (SOS) is a frequent, troubling, and potentially fatal complication of hematopoietic stem cell transplantation. Despite promising results with defibrotide (DF), no treatment has been established as standard. DF is a single-stranded polydeoxyribonucleotide, obtained from controlled depolymerization of porcine intestinal mucosal cells. It has antithrombotic, antiischemic, antiinflammatory, and thrombolytic properties without significant side effects. We retrospectively evaluated the charts of 80 consecutive patients, with 89 hematopoietic stem cell transplants for hematologic malignancies. The results of early initiation of DF treatment in 14 patients with SOS are presented in this study. Fourteen patients, 8 males and 6 females % median age 40.5 years (range, 16-46 years) were diagnosed to have SOS. Disease severity was classified as severe in 6 (42.85%), moderate in 4 (28.57%), and mild in 4 (28.57%) patients. We treated 14 patients with DF for a median of 21.5 days (range, 4-39 days). All 14 patients received DF after the diagnosis of SOS. Three patients with severe and all of the patients with mild to moderate SOS responded to treatment with complete resolution of SOS-related signs and symptoms. All patients responding to DF were alive at 100 days posttransplantation. There was no significant drug-related side effect among patients treated with DF. With an overall response rate of 78.56% and a 50% complete response rate in severe SOS cases and minimal side effects, we suggest that DF is the best available agent to treat SOS.