Randomized clinical trial on acute effects of i.v. iron sucrose during haemodialysis

Treatment of Iron Deficiency in Heart Failure

PURPOSE OF REVIEW

Heart failure (HF) is commonly associated with iron deficiency (ID), defined as insufficient levels of iron to meet physiological demands. ID's association with anaemia is well understood but it is increasingly recognised as an important comorbidity in HF, even in the absence of anaemia. This review summarises contemporary evidence for the measurement and treatment of ID, in both HFrEF and HFpEF, and specific HF aetiologies, and highlights important gaps in the evidence-base.

RECENT FINDINGS

ID is common among patients with HF and associated with increased morbidity and mortality. Correcting ID in patients with HF can impact upon functional status, exercise tolerance, symptoms, and overall quality of life, irrespective of anaemia status. ID is a modifiable comorbidity in HF. Therefore, recognising and treating ID has emerging therapeutic potential and is important for all clinicians who care for patients with HF to understand the rationale and approach to treatment.

N-Acetylcysteine: more than preventing contrast-induced nephropathy in uremic patients-focus on the antioxidant and anti-inflammatory properties

Oxidative stress (OS) has been recognized as a pathophysiologic mechanism underlying the development and progression of chronic kidney disease (CKD). OS, which results from the disturbance of balance among pro-oxidants and antioxidants favoring the pro-oxidants, is present even in early CKD and increases progressively along with deterioration of kidney function to end-stage kidney disease (ESKD). In ESKD, OS is further exacerbated mainly due to dialysis procedures per se and predisposes to increased cardiovascular morbidity and mortality. Therefore, since OS plays a pivotal role in the pathogenesis and progression of atherosclerosis in uremic patients, several strategies aiming to ameliorate OS in these patients have been proposed. Among those, N-acetylcysteine (NAC), a thiol-containing antioxidant agent, has attracted special attention due to its pleiotropic functions and beneficial effect in various OS-related entities including paracetamol overdose and prevention of contrast-induced nephropathy. In this review, we present the currently available literature on the antioxidant and anti-inflammatory properties of NAC in CKD, including hemodialysis and peritoneal dialysis.

Pharmacokinetics and Safety of Ferric Pyrophosphate Citrate in Chinese Subjects with and without Hemodialysis-Dependent Stage 5 Chronic Kidney Disease

BACKGROUND AND OBJECTIVE

Anemia caused by iron depletion is common in patients with hemodialysis-dependent stage 5 chronic kidney disease (CKD-5HD) patients. To maintain the iron levels, external administration of iron is essential. Ferric pyrophosphate citrate (FPC) is a novel, water-soluble complex iron salt. The present study was conducted to evaluate the pharmacokinetic (PK) parameters and safety of FPC in adult healthy Chinese subjects and patients with CKD-5HD.

METHODS

Two open-label, single-center studies were conducted in healthy subjects and patients with CKD-5HD. Healthy subjects received a single intravenous dose of 6.5 mg FPC solution, while CKD-5HD patients were randomized to two different sequences of FPC administration at two sequential hemodialysis (HD) treatments (dose 1 and dose 2). Patients received 27.2 mg of FPC at a dialysate concentration of 95 μg/L for 4 h or a single 6.5 mg dose of FPC administered intravenously via the pre-dialyzer blood circuit. The primary objective was to determine the PK parameters of total serum iron (Fetot), while the secondary objective was the safety of the FPC solution. PK parameters were calculated using Phoenix WinNonlin 8.1 and other parameters were analyzed using SAS 9.4 software. Comparison between HD dose 2 and HD dose 1 was performed using the Wilcoxon rank-sum test and analysis of variance (ANOVA).

RESULTS

A total of 14 healthy subjects with a mean age of 30.8 ± 5.92 years and 12 HD patients with a mean age of 54.3 ± 16.47 years were included. In healthy subjects, the peak serum concentration was reached at the end of infusion of FPC, with an adjusted mean maximum concentration (Cmax,) of 33.46 ± 4.83 μmol/L at a mean time to reach Cmax (Tmax) of 4.09 ± 0.19 h. In patients with CKD-5HD, the adjusted mean Cmax of HD dose 2 was 25.37 ± 4.30 μmol/L at a Tmax, of 3.09 ± 0.32 h, whereas the Cmax, of HD dose 1 was 24.59 ± 4.77 μmol/L at a Tmax, of 3.96 ± 0.26 h. The Fetot concentration-time curves were observed to be similar for both administration methods (HD doses 1 and 2), while the PK parameters differed significantly for Tmax (p = 0.001; baseline correction) and area under the concentration-time curve from time zero to time t (AUCt) [p = 0.031 for cycle variance; without baseline correction] between HD doses 1 and 2. The geometric mean ratios (HD dose 1/HD dose 2) for Cmax and AUCt were within the 85-125% range (Cmax 96.56%; AUCt 96.07%). A total of three and two incidences of adverse events were reported in healthy subjects and patients with CKD-5HD, respectively.

CONCLUSION

FPC showed a good PK and safety profile and hence can be used as maintenance therapy for patients with CKD-5HD by choosing a better method of administration based on clinical feasibility and requirement.

CLINICAL TRIAL REGISTRATION

CTR20181113 and CTR20181119.

TAM-ing the CIA-Tumor-Associated Macrophages and Their Potential Role in Unintended Side Effects of Therapeutics for Cancer-Induced Anemia

Cancer-induced anemia (CIA) is a common consequence of neoplasia and has a multifactorial pathophysiology. The immune response and tumor treatment, both intended to primarily target malignant cells, also affect erythropoiesis in the bone marrow. In parallel, immune activation inevitably induces the iron-regulatory hormone hepcidin to direct iron fluxes away from erythroid progenitors and into compartments of the mononuclear phagocyte system. Moreover, many inflammatory mediators inhibit the synthesis of erythropoietin, which is essential for stimulation and differentiation of erythroid progenitor cells to mature cells ready for release into the blood stream. These pathophysiological hallmarks of CIA imply that the bone marrow is not only deprived of iron as nutrient but also of erythropoietin as central growth factor for erythropoiesis. Tumor-associated macrophages (TAM) are present in the tumor microenvironment and display altered immune and iron phenotypes. On the one hand, their functions are altered by adjacent tumor cells so that they promote rather than inhibit the growth of malignant cells. As consequences, TAM may deliver iron to tumor cells and produce reduced amounts of cytotoxic mediators. Furthermore, their ability to stimulate adaptive anti-tumor immune responses is severely compromised. On the other hand, TAM are potential off-targets of therapeutic interventions against CIA. Red blood cell transfusions, intravenous iron preparations, erythropoiesis-stimulating agents and novel treatment options for CIA may interfere with TAM function and thus exhibit secondary effects on the underlying malignancy. In this Hypothesis and Theory, we summarize the pathophysiological hallmarks, clinical implications and treatment strategies for CIA. Focusing on TAM, we speculate on the potential intended and unintended effects that therapeutic options for CIA may have on the innate immune response and, consequently, on the course of the underlying malignancy.

Route of intestinal absorption and tissue distribution of iron contained in the novel phosphate binder ferric citrate

BACKGROUND

Anemia of chronic kidney disease (CKD) is, in part, caused by hepcidin-mediated impaired iron absorption. However, phosphate binder, ferric citrate (FC) overcomes the CKD-induced impairment of iron absorption and increases serum iron, transferrin saturation, and iron stores and reduces erythropoietin requirements in CKD/ESRD patients. The mechanism and sites of intestinal absorption of iron contained in FC were explored here.

METHODS

Eight-week old rats were randomized to sham-operated or 5/6 nephrectomized (CKD) groups and fed either regular rat chow or rat chow containing 4% FC for 6 weeks. They were then euthanized, and tissues were processed for histological and biochemical analysis using Prussian blue staining, Western blot analysis to quantify intestinal epithelial tight junction proteins and real-time PCR to measure Fatty Acid receptors 2 (FFA2) and 3 (FFA3) expressions.

RESULTS

CKD rats exhibited hypertension, anemia, azotemia, and hyperphosphatemia. FC-treated CKD rats showed significant reductions in blood pressure, serum urea, phosphate and creatinine levels and higher serum iron and blood hemoglobin levels. This was associated with marked increase in iron content of the epithelial and subepithelial wall of the descending colon and modest iron deposits in the proximal tubular epithelial cells of their remnant kidneys. No significant difference was found in hepatic tissue iron content between untreated and FC-treated CKD or control groups. Distal colon's epithelial tight Junction proteins, Occludin, JAM-1 and ZO-1 were markedly reduced in the CKD groups. The FFA2 expression in the jejunum and FFA3 expression in the distal colon were significantly reduced in the CKD rats and markedly increased with FC administration.

CONCLUSION

Iron contained in the phosphate binder, FC, is absorbed by the distal colon of the CKD animals via disrupted colonic epithelial barrier and upregulation of short chain fatty acid transporters.

Acute Effects of Iron Sucrose and Iron Carboxymaltose on Endothelial Function in Nondialysis Chronic Kidney Disease Patients

BACKGROUND

Intravenous iron is commonly prescribed in chronic kidney disease (CKD) patients. Iron sucrose (IS) and ferric carboxymaltose (FCM) are 2 frequently used formulations. Experimental data showed that this 2 intravenous iron preparations have different potential to induce oxidative stress and by that endothelial dysfunction. Still, direct comparisons in clinical settings are rather scarce.

STUDY QUESTION

Are there any acute changes in endothelial function after single intravenous iron infusions of IS and FCM in nondialysis CKD patients?

STUDY DESIGN

This was a prospective, crossover study in which 31 patients with CKD stages 3-5 (80% stages 3 and 4, 81% female, 55% older than 60 years, 23% diabetes mellitus, and 94% arterial hypertension) who required intravenous iron as part of their routine medical care were enrolled.

MEASURES AND OUTCOMES

The effect of flow-mediated vasodilatation infusions containing 250-mL 10% glucose, 500-mg FCM, and 200-mg IS, both in 250-mL 0.9% saline solution, was compared. The infusions were administered over 30 minutes, 72 hours apart, in the mentioned order. Ultrasound measurement of the brachial artery flow-mediated vasodilation (FMD) performed 15 minutes before and after each infusion was used to assess endothelial function. The outcome was the post/preinfusion difference (Δ) in FMD.

RESULTS

The baseline FMD was similar before each study intervention. The arterial reactivity significantly decreased only after IS infusion [ΔFMD -2.3 (-5.65 to -0.33) vs. 1.0 (-1.49 to 1.80) after glucose, P = 0.01], but not after FCM [ΔFMD -0.8 (-2.50 to 0.65), P = 0.27 vs. glucose]. Moreover, the arterial reactivity was higher after IS as compared to FCM.

CONCLUSIONS

Endothelial dysfunction seems to be acutely induced by a single dose of intravenous IS, but not by FCM, in nondialysis CKD patients.

Antioxidant Supplementation in Renal Replacement Therapy Patients: Is There Evidence?

The disruption of balance between production of reactive oxygen species and antioxidant systems in favor of the oxidants is termed oxidative stress (OS). To counteract the damaging effects of prooxidant free radicals, all aerobic organisms have antioxidant defense mechanisms that are aimed at neutralizing the circulating oxidants and repair the resulting injuries. Antioxidants are either endogenous (the natural defense mechanisms produced by the human body) or exogenous, found in supplements and foods. OS is present at the early stages of chronic kidney disease, augments progressively with renal function deterioration, and is further exacerbated by renal replacement therapy. End-stage renal disease patients, on hemodialysis (HD) or peritoneal dialysis (PD), suffer from accelerated OS, which has been associated with increased risk for mortality and cardiovascular disease. During HD sessions, the bioincompatibility of dialyzers and dialysate trigger activation of white blood cells and formation of free radicals, while a significant loss of antioxidants is also present. In PD, the bioincompatibility of solutions, including high osmolality, elevated lactate levels, low pH, and accumulation of advanced glycation end-products trigger formation of prooxidants, while there is significant loss of vitamins in the ultrafiltrate. A number of exogenous antioxidants have been suggested to ameliorate OS in dialysis patients. Vitamins B, C, D, and E, coenzyme Q10, L-carnitine, a-lipoic acid, curcumin, green tea, flavonoids, polyphenols, omega-3 polyunsaturated fatty acids, statins, trace elements, and N-acetylcysteine have been studied as exogenous antioxidant supplements in both PD and HD patients.

Oxidative stress in hemodialysis: Causative mechanisms, clinical implications, and possible therapeutic interventions

Oxidative stress (OS) is the result of prooxidant molecules overwhelming the antioxidant defense mechanisms. Hemodialysis (HD) constitutes a state of elevated inflammation and OS, due to loss of antioxidants during dialysis and activation of white blood cells triggering production of reactive oxygen species. Dialysis vintage, dialysis methods, and type and condition of vascular access, biocompatibility of dialyzer membrane and dialysate, iron administration, and anemia all can play a role in aggravating OS, which in turn has been associated with increased morbidity and mortality. Oral or intravenous administration of antioxidants may detoxify the oxidative molecules and at least in part repair OS-mediated tissue damage. Lifestyle interventions and optimization of a highly biocompatible HD procedure might ameliorate OS development in dialysis.

Oral Ferric Citrate Hydrate Associated With Less Oxidative Stress Than Intravenous Saccharated Ferric Oxide

Introduction

A recent study suggested that orally dosed ferric citrate hydrate (FC) corrects renal anemia in patients on hemodialysis (HD), suggesting biological differences in effects of iron supplementation using different routes of administration. To address this issue, the present study compared oral FC with i.v. saccharated ferric oxide (FO) in stable HD patients.

Methods

Participants comprised 6 patients administered 3 consecutive protocols in the first HD session of the week in a fasting state: nothing given, as control (C); oral load of FC (480 mg iron), and 5 minutes of i.v. FO (40 mg iron). Iron dynamics in the body and biological impact on redox-inflammation status during the study (6 hours) were examined.

Results

Significant increases in serum iron and transferrin saturation were seen with both FC and FO. Regarding total iron-binding capacity as the sum of serum iron and unsaturated iron-binding capacity, no changes were found in FC, whereas significant increases were seen in FO (appearance of non–transferrin-binding iron [NTBI]), despite the lower serum iron levels in FO. Compared with C, increases were seen in serum myeloperoxidase (oxidative marker) with accompanying significant decreases in thioredoxin (antioxidant) in FO, whereas no changes were found in FC.

Conclusion

Oral FC differs from i.v. FO in areas such as less NTBI generation and less induction of oxidative stress. The result indicates potential clinical benefits of oral FC in terms of iron supplementation for renal anemia in HD patients.

Oxidative Stress in Hemodialysis Patients: A Review of the Literature

Hemodialysis (HD) patients are at high risk for all-cause mortality and cardiovascular events. In addition to traditional risk factors, excessive oxidative stress (OS) and chronic inflammation emerge as novel and major contributors to accelerated atherosclerosis and elevated mortality. OS is defined as the imbalance between antioxidant defense mechanisms and oxidant products, the latter overwhelming the former. OS appears in early stages of chronic kidney disease (CKD), advances along with worsening of renal failure, and is further exacerbated by the HD process per se. HD patients manifest excessive OS status due to retention of a plethora of toxins, subsidized under uremia, nutrition lacking antioxidants and turn-over of antioxidants, loss of antioxidants during renal replacement therapy, and leukocyte activation that leads to accumulation of oxidative products. Duration of dialysis therapy, iron infusion, anemia, presence of central venous catheter, and bioincompatible dialyzers are several factors triggering the development of OS. Antioxidant supplementation may take an overall protective role, even at early stages of CKD, to halt the deterioration of kidney function and antagonize systemic inflammation. Unfortunately, clinical studies have not yielded unequivocal positive outcomes when antioxidants have been administered to hemodialysis patients, likely due to their heterogeneous clinical conditions and underlying risk profile.

The Ferumoxytol for Anemia of CKD Trial (FACT)-a randomized controlled trial of repeated doses of ferumoxytol or iron sucrose in patients on hemodialysis: background and rationale

Background

Iron deficiency anemia (IDA) is a common manifestation of chronic kidney disease (CKD), affecting most patients on hemodialysis and imposing a substantial clinical burden. Treatment with iron supplementation increases hemoglobin levels and can reduce the severity of anemia in patients with CKD. While correcting anemia in these patients is an important therapeutic goal, there is a lack of long-term trials directly comparing intravenous iron therapies in patients with CKD receiving hemodialysis.

Methods/Design

The Ferumoxytol for Anemia of CKD Trial (FACT) is a 13-month, open-label, randomized, multicenter, international, prospective study with 2 substudies. Entry criteria for the main study include adults with IDA (defined as hemoglobin <11.5 g/dL [<115.0 g/L] and a transferrin saturation <30%), serum ferritin <800 ng/mL (<1798 pmol/L), and receiving hemodialysis for ≥3 months. Patients are randomized to receive ferumoxytol (1.02 g over 2 doses) or iron sucrose (1.0 g over 10 doses) during the initial 5-week treatment period. Those with persistent/recurrent IDA over the 11-month observation period will receive additional 5-week treatment periods, as appropriate. The primary efficacy endpoint of the main study is the mean change in hemoglobin from Baseline to Week 5 for each treatment period. The secondary efficacy endpoints include the mean change in transferrin saturation from Baseline to Week 5 and the proportion of patients with a hemoglobin increase of ≥1.0 g/dL at any time from Baseline to Week 5. Safety will be assessed through an examination of the adverse event profile over the course of the study. An “oxidative stress” substudy in approximately 100 patients will assess the effects of treatment on biomarkers of oxidative stress/inflammation during the initial 5-week treatment period, and a magnetic resonance imaging substudy in approximately 70 patients will assess the potential for iron deposition in target tissues over 24 months.

Discussion

FACT fulfills the need for a long-term comparative trial in patients with IDA and CKD receiving hemodialysis. The efficacy and safety results will provide useful information for guiding therapy in this population. Two hundred ninety-six patients have been enrolled, and completion of the main study is expected soon.

Trial registration

ClinicalTrials.gov identifier: NCT01227616 (registered October 22, 2010); EudraCT number: 2010-022133-28

Does IV Iron Induce Plasma Oxidative Stress in Critically Ill Patients? A Comparison With Healthy Volunteers

OBJECTIVE

To compare the oxidative stress induced by IV iron infusion in critically ill patients and in healthy volunteers.

DESIGN

Multicenter, interventional study.

SETTING

Two ICUs and one clinical research center.

SUBJECTS

Anemic critically ill patients treated with IV iron and healthy volunteers.

INTERVENTIONS

IV infusion of 100 mg of iron sucrose.

MEASUREMENTS AND MAIN RESULTS

Thirty-eight anemic patients (hemoglobin, median [interquartile range] = 8.4 g/dL [7.7-9.2]) (men, 25 [66%]; aged 68 yr [48-77]; Simplified Acute Physiology Score II, 48.5 [39-59]) and 39 healthy volunteers (men, 18 [46%]; aged 42.1 yr [29-50]) were included. Blood samples were drawn before (H0) and 2, 6, and 24 hours (H2, H6, and H24) after a 60-minute iron infusion for the determination of nontransferrin bound iron, markers of lipid peroxidation-8α-isoprostanes, protein oxidation-advanced oxidized protein product, and glutathione reduced/oxidized. Iron infusion had no effect on hemodynamic parameter in patients and volunteers. At baseline, patients had much higher interleukin-6, C-reactive protein, and hepcidin levels. 8α-isoprostanes was also higher in patients at baseline (8.5 pmol/L [6.5-12.9] vs 4.6 pmol/L [3.5-5.5]), but the area under the curve above baseline from H0 to H6 was not different (p = 0.38). Neither was it for advanced oxidized protein product and nontransferrin bound iron. The area under the curve above baseline from H0 to H6 (glutathione reduced/oxidized) was lower in volunteers (p = 0.009). Eight patients had a second set of dosages (after the fourth iron infusion), showing higher increase in 8α-isoprostanes.

CONCLUSIONS

In our observation, IV iron infusion does not induce more nontransferrin bound iron, lipid, or protein oxidation in patients compared with volunteers, despite higher inflammation, oxidative stress, and hepcidin levels and lower antioxidant at baseline. In contrary, iron induces a greater decrease in antioxidant, compatible with higher oxidative stress in volunteers than in critically ill patients.

New Options for Iron Supplementation in Maintenance Hemodialysis Patients

End-stage renal disease results in anemia caused by shortened erythrocyte survival, erythropoietin deficiency, hepcidin-mediated impairment of intestinal absorption and iron release, recurrent blood loss, and impaired responsiveness to erythropoiesis-stimulating agents (ESAs). Iron malabsorption renders oral iron products generally ineffective, and intravenous (IV) iron supplementation is required in most patients receiving maintenance hemodialysis (HD). IV iron is administered at doses far exceeding normal intestinal iron absorption. Moreover, by bypassing physiologic safeguards, indiscriminate use of IV iron overwhelms transferrin, imposing stress on the reticuloendothelial system that can have long-term adverse consequences. Unlike conventional oral iron preparations, ferric citrate has recently been shown to be effective in increasing serum ferritin, hemoglobin, and transferrin saturation values while significantly reducing IV iron and ESA requirements in patients treated with HD. Ferric pyrophosphate citrate is a novel iron salt delivered by dialysate; by directly reaching transferrin, its obviates the need for storing administered iron and increases transferrin saturation without increasing serum ferritin levels. Ferric pyrophosphate citrate trials have demonstrated effective iron delivery and stable hemoglobin levels with significant reductions in ESA and IV iron requirements. To date, the long-term safety of using these routes of iron administration in patients receiving HD has not been compared to IV iron and therefore awaits future investigations.

Iron therapy for the treatment of iron deficiency in chronic heart failure: intravenous or oral?

This article considers the use and modality of iron therapy to treat iron deficiency in patients with heart failure, an aspect of care which has received relatively little attention compared with the wider topic of anaemia management. Iron deficiency affects up to 50% of heart failure patients, and is associated with poor quality of life, impaired exercise tolerance, and mortality independent of haematopoietic effects in this patient population. The European Society of Cardiology Guidelines for heart failure 2012 recommend a diagnostic work-up for iron deficiency in patients with suspected heart failure. Iron absorption from oral iron preparations is generally poor, with slow and often inefficient iron repletion; moreover, up to 60% of patients experience gastrointestinal side effects. These problems may be exacerbated in heart failure due to decreased gastrointestinal absorption and poor compliance due to pill burden. Evidence for clinical benefits using oral iron is lacking. I.v. iron sucrose has consistently been shown to improve exercise capacity, cardiac function, symptom severity, and quality of life. Similar findings were observed recently for i.v. ferric carboxymaltose in patients with systolic heart failure and impaired LVEF in the double-blind, placebo-controlled FAIR-HF and CONFIRM-HF trials. I.v. iron therapy may be better tolerated than oral iron, although confirmation in longer clinical trials is awaited. Routine diagnosis and management of iron deficiency in patients with symptomatic heart failure regardless of anaemia status is advisable, and, based on current evidence, prompt intervention using i.v. iron therapy should now be considered.

The complex interplay of iron metabolism, reactive oxygen species, and reactive nitrogen species: insights into the potential of various iron therapies to induce oxidative and nitrosative stress

Production of minute concentrations of superoxide (O2(*-)) and nitrogen monoxide (nitric oxide, NO*) plays important roles in several aspects of cellular signaling and metabolic regulation. However, in an inflammatory environment, the concentrations of these radicals can drastically increase and the antioxidant defenses may become overwhelmed. Thus, biological damage may occur owing to redox imbalance-a condition called oxidative and/or nitrosative stress. A complex interplay exists between iron metabolism, O2(*-), hydrogen peroxide (H2O2), and NO*. Iron is involved in both the formation and the scavenging of these species. Iron deficiency (anemia) (ID(A)) is associated with oxidative stress, but its role in the induction of nitrosative stress is largely unclear. Moreover, oral as well as intravenous (iv) iron preparations used for the treatment of ID(A) may also induce oxidative and/or nitrosative stress. Oral administration of ferrous salts may lead to high transferrin saturation levels and, thus, formation of non-transferrin-bound iron, a potentially toxic form of iron with a propensity to induce oxidative stress. One of the factors that determine the likelihood of oxidative and nitrosative stress induced upon administration of an iv iron complex is the amount of labile (or weakly-bound) iron present in the complex. Stable dextran-based iron complexes used for iv therapy, although they contain only negligible amounts of labile iron, can induce oxidative and/or nitrosative stress through so far unknown mechanisms. In this review, after summarizing the main features of iron metabolism and its complex interplay with O2(*-), H2O2, NO*, and other more reactive compounds derived from these species, the potential of various iron therapies to induce oxidative and nitrosative stress is discussed and possible underlying mechanisms are proposed. Understanding the mechanisms, by which various iron formulations may induce oxidative and nitrosative stress, will help us develop better tolerated and more efficient therapies for various dysfunctions of iron metabolism.

Understanding iron: promoting its safe use in patients with chronic kidney failure treated by hemodialysis

Although judicious use of intravenous iron preparations is an indispensable part of anemia treatment in hemodialysis patients, their excessive and indiscriminate use can have insidious but serious adverse consequences. With recent implementation of the bundling reimbursement policy, use of intravenous iron preparations in the hemodialysis population has markedly increased. Excessive use of these agents potentially can exacerbate oxidative stress, inflammation, endothelial dysfunction, cardiovascular disease, and immune deficiency and potentially increases the risk of microbial infections in this population. Most of these adverse effects are mediated by iron-catalyzed generation of reactive oxygen species and the resultant cell injury and dysfunction. This review is intended to provide an overview of the nature and mechanisms of the adverse effects of iron overload and call for the judicious use of these vitally important products.

Ischemia modified albumin and carbonyl protein as potential biomarkers of protein oxidation in hemodialysis

OBJECTIVE

The aim of this study was to evaluate the effect of HD on ischemia modified albumin (IMA) and protein carbonyl groups in order to investigate the role of IMA as a marker of protein oxidation.

DESIGN AND METHODS

This study was conducted with 23 chronic hemodialysis patients. The serum IMA levels and protein carbonyl groups were measured immediately before hemodialysis (pre-HD) and after the end of hemodialysis (post-HD).

RESULTS

IMA concentrations were significantly higher in post-HD than those of the pre-HD and carbonyl protein concentrations were higher in post-HD in comparison with pre-HD. A significant correlation was observed between IMA and carbonyl protein levels.

CONCLUSIONS

The increase of IMA levels and protein carbonyl groups post-HD could be attributed to the increase of oxidative stress associated with HD, and IMA appears to be an important biomarker for assessing protein oxidation after HD.

Iron sucrose promotes endothelial injury and dysfunction and monocyte adhesion/infiltration

BACKGROUND/AIMS

Intravenous (IV) iron preparations are widely used in the management of anemia in ESRD populations. Recent changes in reimbursement policy have dramatically increased the use of IV iron to lower the use of costly erythropoiesis-stimulating agents. These preparations are frequently administered with insufficient attention to the total body iron stores or presence of inflammation which is aggravated by excess iron. Endothelial injury and dysfunction are critical steps in atherosclerosis, thrombosis and cardiovascular disease. IV iron preparations raise plasma non-transferrin-bound iron which can promote oxidative stress, endothelial damage and dysfunction. We explored the effect of an IV iron preparation on endothelial cells, monocytes and isolated arteries.

METHODS

Primary cultures of human aortic endothelial cells (HAEC) were treated with pharmacologically relevant concentrations of iron sucrose (10-100 μg/ml) for 4-24 h. Endothelial cell morphology, viability, and monocyte adhesion were tested. Endothelial function was assessed by measuring the vasorelaxation response to acetylcholine in normal rat thoracic aorta rings preincubated with iron sucrose (200 μg/ml).

RESULTS

In contrast to the control HAEC which showed normal cobblestone appearance, cells treated with iron sucrose (50-100 μg/ml) for 4 h showed loss of normal morphological characteristics, cellular fragmentation, shrinkage, detachment, monolayer disruption and nuclear condensation/fragmentation features signifying apoptosis. HAEC exposure to iron sucrose (10-100 μg/ml) increased monocyte adhesion 5- to 25-fold. Incubation in media containing 200 μg/ml iron sucrose for 3 h caused marked reduction in the acetylcholine-mediated relaxation in phenylephrine-precontracted rat aorta.

CONCLUSION

Pharmacologically relevant concentration of iron sucrose results in endothelial injury and dysfunction and marked increase in monocyte adhesion.

Iron overdose: a contributor to adverse outcomes in randomized trials of anemia correction in CKD

Administration of intravenous iron to supplement erythropoiesis stimulating agents (ESAs) has become a common practice in the management of anemia in patients with end-stage renal disease. Randomized clinical trials of anemia correction in this population have shown more adverse outcomes in CKD and ESRD patients assigned to the higher hemoglobin targets. Retrospective analysis of these trials suggests that morbidity is higher in subjects who fail to achieve the designated hemoglobin target and are typically exposed to higher doses of ESAs and iron than those that easily achieve the intended targets. Intravenous iron administration circumvents the natural biologic mechanisms for handling and utilization of iron. There is in vitro and in vivo evidence that intravenous iron preparations can cause oxidative stress, endothelial dysfunction, inflammation, impaired immunity, and renal injury. Since iron overload is known to promote endothelial dysfunction, cardiovascular disease, and immune dysfunction which are the leading causes of premature mortality in CKD and ESRD patients, it is imperative to exercise caution with the use of IV iron preparations in this population. The present review is intended to provide a brief overview of the potential adverse effects of the overzealous use of these agents.

Do two intravenous iron sucrose preparations have the same efficacy?

Background. Intravenous (i.v.) iron sucrose similar (ISS) preparations are available but clinical comparisons with the originator iron sucrose (IS) are lacking.

Methods. The impact of switching from IS to ISS on anaemia and iron parameters was assessed in a sequential observational study comparing two periods of 27 weeks each in 75 stable haemodialysis (HD) patients receiving i.v. iron weekly and an i.v. erythropoiesis-stimulating agent (ESA) once every 2 weeks. Patients received IS in the first period (P1) and ISS in the second period (P2).

Results. Mean haemoglobin value was 11.78 ± 0.99 g/dL during P1 and 11.48 ± 0.98 g/dL during P2 (P = 0.01). Mean serum ferritin was similar for both treatment periods (P1, 534 ± 328 μg/L; P2, 495 ± 280 μg/L, P = 0.25) but mean TSAT during P1 (49.3 ± 10.9%) was significantly higher than during P2 (24.5 ± 9.4%, P <0.0001). The mean dose of i.v. iron per patient per week was 45.58 ± 32.55 mg in P1 and 61.36 ± 30.98 mg in P2 (+34.6%), while the mean ESA dose was 0.58 ± 0.52 and 0.66 ± 0.64 μg/kg/week, respectively (+13.8%). Total mean anaemia drug costs increased in P2 by 11.9% compared to P1.

Conclusions. The switch from the originator IS to an ISS preparation led to destabilization of a well-controlled population of HD patients and incurred an increase in total anaemia drug costs. Prospective comparative clinical studies are required to prove that ISS are as efficacious and safe as the originator i.v. IS.