Catalytically active iron and bacterial growth in serum of haemodialysis patients after i.v. iron-saccharate administration

The pathogenesis of CKD complications; Attack of dysregulated iron and phosphate metabolism

Chronic kidney disease (CKD) patients have a tremendously higher risk of developing cardiovascular disease (CVD) and infection than the non-CKD population, which could be caused by intertwining actions of hyperphosphatemia and CKD associated misdistribution of iron. CVD is often associated with vascular calcification, which has been attributed to hyperphosphatemia, and could be initiated in mitochondria, inducing apoptosis, and accelerated by reactive oxygen species (ROS). The production of ROS is principally linked to intracellular ferrous iron. For infection, the virulence and pathogenicity of a pathogen is directly related to its capacity to acquire iron for proliferation and to escape or subvert the host's immune response. Iron administration for renal anemia can sometimes be overdosed, which could decrease host immune mechanisms through its direct effect on neutrophils, macrophages and T cell function. Hyperphosphatemia has been demonstrated to be associated with an increased incidence of infection. We hypothesized two possible mechanisms: 1) fibroblast growth factor-23 levels are increased in parallel with serum phosphate levels and directly impair leukocyte recruitment and host defense mechanisms, and 2) circulating non-transferrin-bound iron (NTBI) is increased due to decreased iron binding capacity of the carrier protein transferrin in high-phosphate conditions. From these observations, maintaining an adequate serum range of phosphate levels and minimizing intracellular iron accumulation could attenuate the development of CKD complications.

Factors influencing safety and efficacy of intravenous iron-carbohydrate nanomedicines: From production to clinical practice

Iron deficiency is an important subclinical disease affecting over one billion people worldwide. A growing body of clinical records supports the use of intravenous iron-carbohydrate complexes for patients where iron replenishment is necessary and oral iron supplements are either ineffective or cannot be tolerated by the gastrointestinal tract. A critical characteristic of iron-carbohydrate drugs is the complexity of their core-shell structure, which has led to differences in the efficacy and safety of various iron formulations. This review describes parameters influencing the safety and effectiveness of iron-carbohydrate complexes during production, storage, handling, and clinical application. We summarized the physicochemical and biological assessments of commercially available iron carbohydrate nanomedicines to provide an overview of publicly available data. Further, we reviewed studies that described how subtle differences in the manufacturing process of iron-carbohydrate complexes can impact on the physicochemical, biological, and clinical outcomes of original product versus their intended copies or so-called iron "similar" products.

Efficacy of a Low-Dose Intravenous Iron Sucrose Regimen in Peritoneal Dialysis Patients

Objective

Sufficient iron substitution leads to a decrease in the required recombinant human erythropoietin (rHuEPO) dose and/or an increased hematocrit in dialysis patients. Intravenous (IV) application of larger doses of iron sucrose may be associated with hyperferritinemia, appearance of catalytically free iron, and impaired phagocyte function. Therefore, we investigated the effectiveness of a low-dose IV iron regimen in peritoneal dialysis (PD) patients.

Patients and Interventions

Forty-five PD patients were followed over a period of 1 year. Serum ferritin, serum transferrin saturation, and hemoglobin were measured monthly. In cases of absolute iron deficiency (serum ferritin < 100 μg/L), 50 mg iron sucrose was given IV every second week. In cases of functional iron deficiency (ferritin ≥ 100 μg/L and transferrin saturation < 20%) and in iron repleted patients (ferritin ≥ 100 μg/L and transferrin saturation ≥ 20%), 50 mg IV iron sucrose was applied monthly. Iron therapy was stopped in cases of acute infection (until complete recovery) and when serum ferritin level was ≥ 600 μg/L.

Results

To analyze the influence of iron substitution on erythropoiesis and rHuEPO requirements, the EPO resistance index (ERI; quotient of rHuEPO dose in units/kilogram/week and hemoglobin in grams per deciliter) was calculated every 3 months. The ERI decreased significantly during the course of the study in the whole patient group ( p = 0.009) as well as in the subgroup of 21 patients with absolute iron deficiency ( p = 0.01). A nonsignificant decrease in the ERI was observed within the group of 14 iron repleted patients ( p = 0.5). There was no significant change in the ERI in 10 patients with functional iron deficiency ( p = 0.6).

Conclusion

The low-dose IV iron regimen used in this study substantially decreased rHuEPO requirements in patients with absolute iron deficiency and was effective in maintaining iron stores in iron repleted patients. However, in the absence of significant hyperparathyroidism, aluminum toxicity, or inadequate dialysis, it did not improve the ERI in patients with functional iron deficiency.

Assessment of Acute Serum Iron, Non-Transferrin-Bound Iron, and Gastrointestinal Symptoms with 3-Week Consumption of Iron-Enriched Aspergillus oryzae Compared with Ferrous Sulfate

BACKGROUND

Iron deficiency anemia (IDA) is a widespread nutritional deficiency, and iron supplementation, especially with ferrous sulfate (FeSO4), is the most common strategy to treat IDA; however, compliance is often poor with daily FeSO4 owing to negative side effects. In a previous study, iron from iron-enriched Aspergillus oryzae [Ultimine® Koji Iron (ULT)] was absorbed similarly to FeSO4.

OBJECTIVES

The main objective of this study was to assess the safety of consuming ULT in terms of increasing non-transferrin-bound iron (NTBI) and gastrointestinal distress.

METHODS

Young female participants (n  = 16) with serum ferritin <40 μg/L were randomly assigned to a double-blind, 9-wk crossover study with a 3-wk placebo/washout period between treatments. Oral FeSO 4 and ULT supplements containing 65 mg Fe were administered daily for 21 consecutive days. On day 1, serum iron (SI), percentage transferrin saturation (%TS), and NTBI were measured for 8 h on the first day of iron consumption. Changes in biochemical indicators were evaluated after 3 wk consumption. Side effects questionnaires were completed weekly on 2 randomly selected weekdays and 1 weekend day for the entire study.

RESULTS

SI, %TS, and NTBI were all markedly higher during hours 2-8 (P < 0.001) with FeSO4 than with ULT. Oxidative stress, inflammatory, and kidney and liver function markers remained unchanged with both supplementations compared with placebo. Changes in iron status markers were not significantly different among the 3 treatments. Individual or global side effects were not significantly different among all treatments. Even when common side effects of nausea, constipation, and diarrhea were combined, FeSO4 treatment had a significantly higher effect than ULT (P = 0.04) and placebo (P = 0.004) only at week 3, but the difference was not significant between ULT and placebo.

CONCLUSIONS

Low NTBI production and fewer common gastrointestinal side effects with ULT suggest that it is a safe oral iron supplement to treat IDA. This trial was registered at clinicaltrials.gov as NCT04018300.

Intravenous iron supplementation does not increase infectious disease risk in hemodialysis patients: a nationwide cohort-based case-crossover study

BACKGROUND

Studies have reported conflicting findings on the infection risk posed by intravenous iron supplementation among hemodialysis (HD) patients. We used a novel study design to assess associations between intravenous iron and infectious diseases.

METHODS

Patients initiating HD between 1998 and 2008 were extracted from Taiwan's National Health Insurance Research Database. Their first infectious disease in the period between 1.5 years after dialysis initiation and 2010 was identified and defined as the index date. Through the case-crossover design, the odds of exposure to intravenous iron within the 1-month period immediately preceding the index date (i.e., the case period) were compared with iron exposure in three different matched control periods for the same enrollee, thus possibly reducing some unmeasured confounders.

RESULTS

A total of 1410 patients who met our enrollment criteria were extracted from incident HD patients. The odds of intravenous iron exposure during the case period versus total control periods exhibited no significant difference (odds ratio: 1.000, 95% confidence interval: 0.75-1.33). In subgroup analyses, this association remained nonsignificant across patients with diabetes mellitus, heart failure, chronic lung disease, venous catheter for HD, and higher iron load.

CONCLUSIONS

We found that intravenous iron supplementation did not increase short-term infection risk among HD patients.

Purification and functional characterization of serum transferrin from Nile tilapia (Oreochromis niloticus)

Transferrin (TF), an iron-binding multifunctional protein, could participate in the iron-withholding strategy, an effective antimicrobial defense mechanism in innate immunity, and is involved in host defense against pathogenic infection. In this study, a TF homologue (OnTF) was purified from serum of Nile tilapia (Oreochromis niloticus) through a two-step affinity chromatography, and characterized its antibacterial function and the role in inflammatory response. The identification by mass spectrometry showed that peptide sequence of the purified OnTF was highly consistent with its amino acids sequence, containing two conserved iron binding lobes: N-lobe and C-lobe. The native OnTF was able to bond iron ions, and possessed capability to inhibit the growth of both bacterial pathogens (Streptococcus agalactiae and Aeromonas hydrophila) in vitro. Upon infections of S. agalactiae and A. hydrophila, the expression of OnTF protein was significantly up-regulated in vivo and in vitro. In addition, the OnTF participated in the regulation of inflammation, migration, and enhancement of phagocytosis and respiratory burst activity in head kidney macrophages/monocytes. Taken together, the results of this study indicated that OnTF is likely to involve in innate immunity to play a role in host defense against bacterial infection in Nile tilapia.

Chronic use of oral iron supplements is associated with poor clinical outcomes in patients with gram-negative bacteremia

An unabsorbed dietary iron supplementation can modify the colonic microbiota equilibrium and favor the growth of pathogenic strains over barrier strains. Nevertheless, the impact of oral iron supplements (OIS) use on the clinical outcomes of patients with gram-negative bacteremia (GNB) has not been evaluated. To explore the impact of OIS on the outcomes of patients with GNB. A retrospective study conducted in a tertiary hospital including patients with GNB during 2011-2016. The entire cohort was divided into chronic OIS users (study group) and nonusers (control group). The two groups were compared for the study outcomes, septic shock at presentation, length of hospital stay (LOS), and short-term mortality. The study cohort included 232 patients; 44 patients in the study group and 188 in the control one. There was no any significant difference in demographic and comorbidities characteristics between the two groups. Escherichia coli comprised the majority of bacteria (69%), while the urinary tract was the main source of the bacteremia. OIS alone and after adjustment was significantly associated with septic shock at presentation (OR = 2, CI95% [1.03-5], p = 0.04 and OR = 5, CI95% [1.4-15], p = 0.01, respectively). By multivariate analysis, OIS was significantly associated with 30-day mortality (OR = 3, CI95% [1.05-7], p = 0.04), but had no impact on LOS (16 + 23 vs. 12 + 15, p = 0.9). There is a significant association between chronic OIS exposure and increased adverse outcomes in patients with GNB. These findings might have important clinical implications.

What is the effect of perioperative intravenous iron therapy in patients undergoing non-elective surgery? A systematic review with meta-analysis and trial sequential analysis

Background

Guidelines to treat anaemia with intravenous (IV) iron have focused on elective surgical patients with little attention paid to those undergoing non-elective/emergency surgery. Whilst these patients may experience poor outcomes because of their presenting illness, observational data suggests that untreated anaemia may also be a contributing factor to poor outcomes. We conducted a systematic review to investigate the safety and efficacy of IV iron in patients undergoing non-elective surgery.

Methods

We followed a pre-defined review protocol and included randomised controlled trials (RCTs) in patients undergoing non-elective surgery who received IV iron. Primary outcomes were all-cause infection and mean difference in haemoglobin (Hb) at follow-up. Secondary outcomes included transfusion requirements, hospital length of stay (LOS), health-related quality of life (HRQoL), mortality and adverse events.

Results

Three RCTs (605 participants) were included in this systematic review of which two, in both hip fracture (HF) patients, provided data for meta-analysis. Both of these RCTs were at low risk of bias. We found no evidence of a difference in the risk of infection (RR 0.99, 95% CI 0.55 to 1.80, I ² = 9%) or in the Hb concentration at 'short-term' (≤ 7 days) follow-up (mean difference - 0.32 g/L, 95% CI - 3.28 to 2.64, I ² = 37%). IV iron did not reduce the risk of requiring a blood transfusion (RR 0.90, 95% CI 0.73 to 1.11, p = 0.46, I ² = 0%), and we observed no difference in mortality, LOS or adverse events. One RCT reported on HRQoL and found no difference between treatment arms.

Conclusion

We found no conclusive evidence of an effect of IV iron on clinically important outcomes in patients undergoing non-elective surgery. Further adequately powered trials to evaluate its benefit in emergency surgical specialties with a high burden of anaemia are warranted.

Trial registration

This systematic review was registered on PROSPERO (CRD42018096288).

Safety and efficacy of iron therapy on reducing red blood cell transfusion requirements and treating anaemia in critically ill adults: A systematic review with meta-analysis and trial sequential analysis

PURPOSE

To evaluate the safety (risk of infection) and efficacy (transfusion requirements, changes in haemoglobin (Hb)) of iron therapy in adult intensive care unit (ICU) patients.

MATERIALS AND METHODS

We systematically searched seven databases for all relevant studies until January 2018 and included randomized (RCT) studies comparing iron, by any route, with placebo/no iron.

RESULTS

805 participants from 6 RCTs were included. Iron therapy, by any route, did not decrease the risk of requirement for a red blood cell (RBC) transfusion (Risk ratio (RR) 0.91, 95% CI 0.80 to 1.04, p = 0.15) or mean number of RBCs transfused per participant (mean difference (MD) -0.30, 95% CI -0.68 to 0.07, p = 0.15). Iron therapy did increase mean Hb concentration (MD 0.31 g/dL, 95% CI 0.04 to 0.59, p = 0.03). There was no difference in infection (RR 0.95, 95% CI 0.79 to 1.19, p = 0.44). Trial Sequential Analysis suggests that the required participant numbers to detect or reject a clinically important effect of iron therapy on transfusion requirements or infection in ICU patients has not yet been reached.

CONCLUSION

Iron therapy results in a modest increase in Hb. The current evidence is inadequate to exclude an important effect on transfusion requirements or infection.

Safety of intravenous ferric carboxymaltose versus oral iron in patients with nondialysis-dependent CKD: an analysis of the 1-year FIND-CKD trial

Background. The evidence base regarding the safety of intravenous (IV) iron therapy in patients with chronic kidney disease (CKD) is incomplete and largely based on small studies of relatively short duration.

Methods. FIND-CKD (ClinicalTrials.gov number NCT00994318) was a 1-year, open-label, multicenter, prospective study of patients with nondialysis-dependent CKD, anemia and iron deficiency randomized (1:1:2) to IV ferric carboxymaltose (FCM), targeting higher (400–600 µg/L) or lower (100–200 µg/L) ferritin, or oral iron. A post hoc analysis of adverse event rates per 100 patient-years was performed to assess the safety of FCM versus oral iron over an extended period.

Results. The safety population included 616 patients. The incidence of one or more adverse events was 91.0, 100.0 and 105.0 per 100 patient-years in the high ferritin FCM, low ferritin FCM and oral iron groups, respectively. The incidence of adverse events with a suspected relation to study drug was 15.9, 17.8 and 36.7 per 100 patient-years in the three groups; for serious adverse events, the incidence was 28.2, 27.9 and 24.3 per 100 patient-years. The incidence of cardiac disorders and infections was similar between groups. At least one ferritin level ≥800 µg/L occurred in 26.6% of high ferritin FCM patients, with no associated increase in adverse events. No patient with ferritin ≥800 µg/L discontinued the study drug due to adverse events. Estimated glomerular filtration rate remained the stable in all groups.

Conclusions. These results further support the conclusion that correction of iron deficiency anemia with IV FCM is safe in patients with nondialysis-dependent CKD.

Balance of Benefit and Risk in Intravenous Iron Treatment in Chronic Kidney Disease

Iron supplementation is an important aspect of treatment for hemodialysis patients, with most administration by an intravenous route. As with any drug, decisions as to treatment are most meaningful when benefits and risks are weighed in the context of the individual patient's clinical characteristics. In this article, knowledge of benefits and risks of intravenous iron are reviewed.

Complexity of intravenous iron nanoparticle formulations: implications for bioequivalence evaluation

Intravenous iron formulations are a class of complex drugs that are commonly used to treat a wide variety of disease states associated with iron deficiency and anemia. Venofer® (iron-sucrose) is one of the most frequently used formulations, with more than 90% of dialysis patients in the United States receiving this formulation. Emerging data from global markets outside the United States, where many iron-sucrose similars or copies are available, have shown that these formulations may have safety and efficacy profiles that differ from the reference listed drug. This may be attributable to uncharacterized differences in physicochemical characteristics and/or differences in labile iron release. As bioequivalence evaluation guidance evolves, clinicians should be educated on these potential clinical issues before a switch to the generic formulation is made in the clinical setting.

Association of Metal Homeostasis and (p)ppGpp Regulation in the Pathophysiology of Enterococcus faecalis

In Enterococcus faecalis, the regulatory nucleotides pppGpp and ppGpp, collectively, (p)ppGpp, are required for growth in blood, survival within macrophages, and virulence. However, a clear understanding of how (p)ppGpp promotes virulence in E. faecalis and other bacterial pathogens is still lacking. In the host, the essential transition metals iron (Fe) and manganese (Mn) are not readily available to invading pathogens because of a host-driven process called nutritional immunity. Considering its central role in adaptation to nutritional stresses, we hypothesized that (p)ppGpp mediates E. faecalis virulence through regulation of metal homeostasis. Indeed, supplementation of serum with either Fe or Mn restored growth and survival of the Δrel ΔrelQ [(p)ppGpp⁰] strain to wild-type levels. Using a chemically defined medium, we found that (p)ppGpp accumulates in response to either Fe depletion or Mn depletion and that the (p)ppGpp⁰ strain has a strong growth requirement for Mn that is alleviated by Fe supplementation. Although inactivation of the nutrient-sensing regulator codY restored some phenotypes of the (p)ppGpp⁰ strain, transcriptional analysis showed that the (p)ppGpp/CodY network does not promote transcription of known metal transporters. Interestingly, physiologic and enzymatic investigations suggest that the (p)ppGpp⁰ strain requires higher levels of Mn in order to cope with high levels of endogenously produced reactive oxygen species (ROS). Because (p)ppGpp mediates antibiotic persistence and virulence in several bacteria, our findings have broad implications and provide new leads for the development of novel therapeutic and preventive strategies against E. faecalis and beyond.

Ferric pyrophosphate citrate as an iron replacement agent for patients receiving hemodialysis

Treatment of anemia remains an integral component in the care of patients with end stage kidney disease receiving dialysis. Currently, both erythropoiesis stimulating agents and iron replacement agents remain important anemia management strategies for patients undergoing hemodialysis (HD). Ferric pyrophosphate citrate (FPC) was approved by the U.S. Food and Drug Administration in January 2015 as an iron replacement product in adult patients receiving long-term maintenance HD. FPC is administered to patients on HD through the dialysate. Multicenter randomized, placebo-controlled phase three clinical studies (CRUISE 1 and 2) have found dialysate FPC to maintain hemoglobin level and iron balance in patients receiving chronic HD. Adverse events were similar in both the dialysate FPC-treated and placebo groups. Another study showed a significant reduction in the prescribed erythropoietin-stimulating agents dose at the end of treatment in the dialysate FPC-treated group compared with placebo. These studies have shown that dialysate FPC is efficacious and well tolerated. In this article, we review clinical studies evaluating the efficacy and safety of FPC and also propose a protocol for iron replacement in HD units where dialysate FPC is to be used.

Safety of intravenous iron in hemodialysis patients

Among end-stage renal disease patients maintained by hemodialysis, anemia has been managed primarily through erythropoiesis-stimulating agents (ESAs) and intravenous (IV) iron. Following concerns about the cardiovascular (CV) safety of ESAs and changes in the reimbursement policies in Medicare's ESRD program, the use of IV iron has increased. IV iron supplementation promotes hemoglobin production and reduces ESA requirements, yet there exists relatively little evidence on the long-term safety of iron supplementation in hemodialysis patients. Labile iron can induce oxidative stress and is also essential in bacterial growth, leading to concerns about IV iron use and risk of CV events and infections in hemodialysis patients. Existing randomized controlled trials provide little evidence about safety due to insufficient power and short follow-up; recent observational studies have been inconsistent, but some have associated iron exposure with increased risk of infections and CV events. Given the widespread use and potential safety concerns related to IV iron, well-designed large prospective studies are needed to assess to identify optimal strategies for iron administration that maximize its benefits while avoiding potential risks.

Safety of Intravenous Iron in Hemodialysis: Longer-term Comparisons of Iron Sucrose Versus Sodium Ferric Gluconate Complex

BACKGROUND

Controversy exists about any differences in longer-term safety across different intravenous iron formulations routinely used in hemodialysis (HD) patients. We exploited a natural experiment to compare outcomes of patients initiating HD therapy in facilities that predominantly (in ≥90% of their patients) used iron sucrose versus sodium ferric gluconate complex.

STUDY DESIGN

Retrospective cohort study of incident HD patients.

SETTING & PARTICIPANTS

Using the US Renal Data System, we hard-matched on geographic region and center characteristics HD facilities predominantly using ferric gluconate with similar ones using iron sucrose. Subsequently, incident HD patients were assigned to their facility iron formulation exposure.

INTERVENTION

Facility-level use of iron sucrose versus ferric gluconate.

OUTCOMES

Patients were followed up for mortality from any, cardiovascular, or infectious causes. Medicare-insured patients were followed up for infectious and cardiovascular (stroke or myocardial infarction) hospitalizations and for composite outcomes with the corresponding cause-specific deaths.

MEASUREMENTS

HRs.

RESULTS

We matched 2,015 iron sucrose facilities with 2,015 ferric gluconate facilities, in which 51,603 patients (iron sucrose, 24,911; ferric gluconate, 26,692) subsequently initiated HD therapy. All recorded patient characteristics were balanced between groups. Over 49,989 person-years, 10,381 deaths (3,908 cardiovascular and 1,209 infectious) occurred. Adjusted all-cause (HR, 0.98; 95% CI, 0.93-1.03), cardiovascular (HR, 0.96; 95% CI, 0.89-1.03), and infectious mortality (HR, 0.98; 95% CI, 0.86-1.13) did not differ between iron sucrose and ferric gluconate facilities. Among Medicare beneficiaries, no differences between ferric gluconate and iron sucrose facilities were observed in fatal or nonfatal cardiovascular events (HR, 1.01; 95% CI, 0.93-1.09). The composite infectious end point occurred less frequently in iron sucrose versus ferric gluconate facilities (HR, 0.92; 95% CI, 0.88-0.96).

LIMITATIONS

Unobserved selection bias from nonrandom treatment assignment.

CONCLUSIONS

Patients initiating HD therapy in facilities almost exclusively using iron sucrose versus ferric gluconate had similar longer-term outcomes. However, there was a small decrease in infectious hospitalizations and deaths in patients dialyzing in facilities predominantly using iron sucrose. This difference may be due to residual confounding, random chance, or a causal effect.

Dietary strategies for improving iron status: balancing safety and efficacy

In light of evidence that high-dose iron supplements lead to a range of adverse events in low-income settings, the safety and efficacy of lower doses of iron provided through biological or industrial fortification of foodstuffs is reviewed. First, strategies for point-of-manufacture chemical fortification are compared with biofortification achieved through plant breeding. Recent insights into the mechanisms of human iron absorption and regulation, the mechanisms by which iron can promote malaria and bacterial infections, and the role of iron in modifying the gut microbiota are summarized. There is strong evidence that supplemental iron given in nonphysiological amounts can increase the risk of bacterial and protozoal infections (especially malaria), but the use of lower quantities of iron provided within a food matrix, ie, fortified food, should be safer in most cases and represents a more logical strategy for a sustained reduction of the risk of deficiency by providing the best balance of risk and benefits. Further research into iron compounds that would minimize the availability of unabsorbed iron to the gut microbiota is warranted.

Sphingobacterium spiritivorum infection in a patient with end stage renal disease on haemodialysis

Background

Sphingobacterium spiritivorum is a microorganism that is ubiquitously found in the environment. However, it is rarely isolated from human clinical specimens. There are few reports to date of Sphingobacterium spiritivorum causing disease in humans.

Case report

We describe a case of Sphingobacterium spiritivorum infection in a patient on haemodialysis, which to our knowledge, has not been described before. Further testing revealed this strain was sensitive to multiple antimicrobials.

Conclusion

Despite interrupted courses of several antibiotics, our patient clinically made a good recovery and continued to receive haemodialysis.

Comparative Short-term Safety of Sodium Ferric Gluconate Versus Iron Sucrose in Hemodialysis Patients

BACKGROUND

Despite different pharmacologic properties, little is known about the comparative safety of sodium ferric gluconate versus iron sucrose in hemodialysis patients.

STUDY DESIGN

Retrospective cohort study using the clinical database of a large dialysis provider (2004-2005) merged with administrative data from the US Renal Data System.

SETTING & PARTICIPANTS

66,207 patients with Medicare coverage who received center-based hemodialysis.

PREDICTORS

Iron formulation use assessed during repeated 1-month exposure periods (n=278,357).

OUTCOMES

All-cause mortality, infection-related hospitalizations and mortality, and cardiovascular-related hospitalizations and mortality occurring during a 3-month follow-up period.

MEASUREMENTS

For all outcomes, we estimated 90-day risk differences between the formulations using propensity score weighting of Kaplan-Meier functions, which controlled for a wide range of demographic, clinical, and laboratory variables. Risk differences were also estimated within various clinically important subgroups.

RESULTS

Ferric gluconate was administered in 11.4%; iron sucrose, in 48.9%; and no iron in 39.7% of the periods. Risks for most study outcomes did not differ between ferric gluconate and iron sucrose; however, among patients with a hemodialysis catheter, use of ferric gluconate was associated with a slightly decreased risk for both infection-related death (risk difference, -0.3%; 95% CI, -0.5% to 0.0%) and infection-related hospitalization (risk difference, -1.5%; 95% CI, -2.3% to -0.6%). Bolus dosing was associated with an increase in infection-related events among both ferric gluconate and iron sucrose users.

LIMITATIONS

Residual confounding and outcome measurement error.

CONCLUSIONS

Overall, the 2 iron formulations studied exhibited similar safety profiles; however, ferric gluconate was associated with a slightly decreased risk for infection-related outcomes compared to iron sucrose among patients with a hemodialysis catheter. These associations should be explored further using other data or study designs.

A randomized trial of intravenous and oral iron in chronic kidney disease

Although iron is commonly used to correct iron deficiency anemia (IDA) in chronic kidney disease (CKD) its effect on kidney function is unclear. To assess this, we randomly assigned patients with Stage 3 and 4 CKD and IDA to either open-label oral ferrous sulfate (69 patients to 325 mg three times daily for 8 weeks) or intravenous iron sucrose (67 patients to 200 mg every 2 weeks, total 1 gram). The primary outcome was the between group difference in slope of measured glomerular filtration rate (mGFR) change over two years. The trial was terminated early on the recommendation of an independent Data and Safety Monitoring Board based on little chance of finding differences in mGFR slopes, but a higher risk of serious adverse events in the intravenous iron treatment group. mGFR declined similarly over two years in both treatment groups (oral −3.6 mL/min/1.73m², intravenous − 4.0 mL/min/1.73m², between group difference − 0.35 mL/min/1.73m² (95% confidence interval −2.9 to 2.3). There were 36 serious cardiovascular events among 19 participants assigned to the oral iron treatment group and 55 events among 17 participants of the intravenous iron group (adjusted incidence rate ratio 2.51 (1.56−4.04). Infections resulting in hospitalizations had a significant adjusted incidence rate ratio of 2.12 (1.24−3.64). Thus, among non-dialyzed patients with CKD and IDA, intravenous iron therapy is associated with an increased risk of serious adverse events, including those from cardiovascular causes and infectious diseases.

Considerations and challenges in defining optimal iron utilization in hemodialysis

Trials raising concerns about erythropoiesis-stimulating agents, revisions to their labeling, and changes to practice guidelines and dialysis payment systems have provided strong stimuli to decrease erythropoiesis-stimulating agent use and increase intravenous iron administration in recent years. These factors have been associated with a rise in iron utilization, particularly among hemodialysis patients, and an unprecedented increase in serum ferritin concentrations. The mean serum ferritin concentration among United States dialysis patients in 2013 exceeded 800 ng/ml, with 18% of patients exceeding 1200 ng/ml. Although these changes are broad based, the wisdom of these practices is uncertain. Herein, we examine influences on and trends in intravenous iron utilization and assess the clinical trial, epidemiologic, and experimental evidence relevant to its safety and efficacy in the setting of maintenance dialysis. These data suggest a potential for harm from increasing use of parenteral iron in dialysis-dependent patients. In the absence of well powered, randomized clinical trials, available evidence will remain inadequate for making reliable conclusions about the effect of a ubiquitous therapy on mortality or other outcomes of importance to dialysis patients. Nephrology stakeholders have an urgent obligation to initiate well designed investigations of intravenous iron in order to ensure the safety of the dialysis population.

The Labile Side of Iron Supplementation in CKD

The practice of intravenous iron supplementation has grown as nephrologists have gradually moved away from the liberal use of erythropoiesis-stimulating agents as the main treatment for the anemia of CKD. This approach, together with the introduction of large-dose iron preparations, raises the future specter of inadvertent iatrogenic iron toxicity. Concerns have been raised in original studies and reviews about cardiac complications and severe infections that result from long-term intravenous iron supplementation. Regarding the iron preparations specifically, even though all the currently available preparations appear to be relatively safe in the short term, little is known regarding their long-term safety. In this review we summarize current knowledge of iron metabolism with an emphasis on the sources and potentially harmful effects of labile iron, highlight the approaches to identifying labile iron in pharmaceutical preparations and body fluids and its potential toxic role as a pathogenic factor in the complications of CKD, and propose methods for its early detection in at-risk patients.

Iron sucrose and ferric carboxymaltose: no correlation between physicochemical stability and biological activity

Intravenous iron preparations, like iron sucrose (IS) and ferric carboxymaltose (FCM) differ in their physicochemical stability. Thus differences in storage and utilization can be expected and were investigated in a non-clinical study in liver parenchyma HepG2-cells and THP-1 macrophages as models for toxicological and pharmacological target cells. HepG2-cells incorporated significant amounts of IS, elevated the labile iron pool (LIP) and ferritin and stimulated iron release. HepG2-cells had lower basal cellular iron and ferritin content than THP-1 macrophages, which showed only marginal accumulation of IS and FCM. However, FCM increased the LIP up to twofold and significantly elevated ferritin within 24 h in HepG2-cells. IS and FCM were non-toxic for HepG2-cells and THP-1 macrophages were more sensitive to FCM compared to IS at all concentrations tested. In a cell-free environment redox-active iron was higher with IS than FCM. Biostability testing via assessment of direct transfer to serum transferrin did not reflect the chemical stability of the complexes (i.e., FCM > IS). Effect of vitamin C on mobilisation to transferrin was an increase with IS and interestingly a decrease with FCM. In conclusion, FCM has low bioavailability for liver parenchyma cells, therefore liver iron deposition is unlikely. Ascorbic acid reduces transferrin-chelatable iron from ferric carboxymaltose, thus effects on hepcidin expression should be investigated in clinical studies.

Comparative short-term safety of bolus versus maintenance iron dosing in hemodialysis patients: a replication study

Background

Recent research has reported that patients receiving bolus (frequent large doses to achieve iron repletion) versus maintenance dosing of iron have an increased short-term risk of infection, but a similar risk of cardiovascular events. We sought to determine whether these findings could be replicated using the same methods and a different data source.

Methods

Clinical data from 6,605 patients of a small U.S. dialysis provider merged with Medicare claims data were examined. Iron dosing patterns (bolus, maintenance, no iron) were identified during 1-month exposure periods and cardiovascular and infection-related outcomes were assessed during 3-month follow-up periods. The effects of bolus versus maintenance dosing were assessed using Cox proportional hazards regression analyses to estimate hazard ratios and semiparametric additive risk models to estimate hazard rate differences, controlling for demographic and clinical characteristics, laboratory values and medications, and comorbidities.

Results

48,050 exposure/follow-up periods were examined. 13.9 percent of the exposure periods were bolus dosing, 49.3 percent were maintenance dosing, and the remainder were no iron use. All of the adjusted hazard ratios were >1.00 for the infection-related outcomes, suggesting that bolus dosing increases the risk of these events. The effects were greatest for hospitalized for infection of any major organ system (hazard ratio 1.13 (1.03, 1.24)) and use of intravenous antibiotics (hazard ratio 1.08 (1.02, 1.15). When examining the subgroup of individuals with catheters, the hazard ratios for the infection-related outcomes were generally greater than in the overall sample. There was little association between type of dosing practice and cardiovascular outcomes.

Conclusions

Results of this study provide further evidence of the association between bolus dosing and increased infection risk, particularly in the subgroup of patients with a catheter, and of the lack of an association between dosing practices and cardiovascular outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2369-15-154) contains supplementary material, which is available to authorized users.

Iron deficiency anemia in heart failure

Anemia and iron deficiency are quite prevalent in patients with heart failure (HF) and may overlap. Both anemia and iron deficiency are associated with worse symptoms and adverse clinical outcomes. In the past few years, there has been an enormous interest in the subject of iron deficiency and its management in patients with HF. In this review, the etiology and relevance of iron deficiency, iron metabolism in the setting of HF, studies on iron supplementation in patients with HF and potential cardiovascular effects of subclinical iron overload are discussed.

Transfusion of older stored blood worsens outcomes in canines depending on the presence and severity of pneumonia

BACKGROUND

In experimental pneumonia we found that transfused older blood increased mortality and lung injury that was associated with increased in vivo hemolysis and elevated plasma cell-free hemoglobin (CFH), non-transferrin-bound iron (NTBI), and plasma labile iron (PLI) levels. In this study, we additionally analyze identically treated animals that received lower or higher bacterial doses.

STUDY DESIGN AND METHODS

Two-year-old purpose-bred beagles (n = 48) challenged intrabronchially with Staphylococcus aureus (0 [n = 8], 1.0 × 10(9) [n = 8], 1.25 × 10(9) [n = 24], and ≥1.5 × 10(9) [n = 8] colony-forming units/kg) were exchange transfused with either 7- or 42-day-old canine universal donor blood (80 mL/kg in four divided doses).

RESULTS

The greater increases in CFH with older blood over days after exchange proved relatively independent of bacterial dose. The lesser increases in CFH observed with fresher blood were bacterial dose dependent potentially related to bacterial hemolysins. Without bacterial challenge, levels of CFH, NTBI, and PLI were significantly higher with older versus fresher blood transfusion but there was no significant measurable injury. With higher-dose bacterial challenge, the elevated NTBI and PLI levels declined more rapidly and to a greater extent after transfusion with older versus fresher blood, and older blood was associated with significantly worse shock, lung injury, and mortality.

CONCLUSION

The augmented in vivo hemolysis of transfused older red blood cells (RBCs) appears to result in excess plasma CFH and iron release, which requires the presence of established infection to worsen outcome. These data suggest that transfused older RBCs increase the risks from infection in septic subjects.

Pretransplantation erythropoiesis-stimulating agent hyporesponsiveness is associated with increased kidney allograft failure and mortality

BACKGROUND

Poor response to erythropoiesis-stimulating agents (ESA) is associated with morbidity and mortality among dialysis patients. It is unclear whether the risk associated with poor ESA response during dialysis extends beyond kidney transplantation. We examined pretransplantation ESA response and its effect on allograft failure and mortality.

METHODS

The cohort included all adult Medicare recipients from the U.S. Renal Data System who had received a kidney transplant during years 2000 to 2007 and had at least 6 months of hemodialysis immediately before transplantation. ESA hyporesponsiveness was primarily defined as a monthly ESA dose of 75,000 units or higher and hematocrit 33% or less for at least 3 consecutive months in the pretransplantation period. Crude and adjusted Cox proportional hazards models and Kaplan-Meier methods were used to estimate the effect of ESA hyporesponsiveness on allograft failure and all-cause mortality.

RESULTS

The study group consisted of 36,450 patients; 1004 exhibited hyporesponsiveness. The adjusted hazard ratios (95% confidence interval) for allograft failure and mortality after transplantation were 1.23 (1.10-1.42) and 1.61 (1.43-1.81), respectively, supporting that poor ESA response during hemodialysis is associated with adverse posttransplantation outcomes.

CONCLUSIONS

ESA hyporesponsiveness may be useful in identifying potential allograft recipients who are at high risk for subsequent morbidity and mortality and may benefit from more intensive pretransplantation and posttransplantation monitoring.

Iron and infection in hemodialysis patients

Intravenous iron is an important component of the treatment of anemia of end-stage renal disease (ESRD), but it is biologically plausible that iron could increase the risk of infection through impairment of neutrophil and T-cell function and promotion of microbial growth. Any such increase in risk would be particularly important because infection is a significant cause of mortality and morbidity in dialysis patients. The overall evidence favors an association between iron and infection in hemodialysis patients, but the optimal iron management strategy to minimize infection risk has yet to be identified. There is a need for further research on this topic, particularly in light of increased utilization of intravenous iron following implementation of the bundled ESRD reimbursement system.

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.

Intravenous iron supplementation practices and short-term risk of cardiovascular events in hemodialysis patients

Background & Objectives

Intravenous iron supplementation is widespread in the hemodialysis population, but there is uncertainty about the safest dosing strategy. We compared the safety of different intravenous iron dosing practices on the risk of adverse cardiovascular outcomes in a large population of hemodialysis patients.

Design settings, participants, & measurements

A retrospective cohort was created from the clinical database of a large dialysis provider (years 2004-2008) merged with administrative data from the United States Renal Data System. Dosing comparisons were (1) bolus (consecutive doses ≥ 100 mg exceeding 600 mg during one month) versus maintenance (all other iron doses during the month); and (2) high (> 200 mg over 1 month) versus low dose (≤ 200 mg over 1 month). We established a 6-month baseline period (to identify potential confounders and effect modifiers), a one-month iron exposure period, and a three-month follow-up period. Outcomes were myocardial infarction, stroke, and death from cardiovascular disease.

Results

117,050 patients contributed 776,203 unique iron exposure/follow-up periods. After adjustment, we found no significant associations of bolus dose versus maintenance, hazards ratio for composite outcome, 1.03 (95% C.I. 0.99, 1.07), or high dose versus low dose intravenous iron, hazards ratio for composite outcome, 0.99 (95% C.I. 0.96, 1.03). There were no consistent associations of either high or bolus dose versus low or maintenance respectively among pre-specified subgroups.

Conclusions

Strategies favoring large doses of intravenous iron were not associated with increased short-term cardiovascular morbidity and mortality. Investigation of the long-term safety of the various intravenous iron supplementation strategies may still be warranted.

Iron toxicity: relevance for dialysis patients

Iron deficiency is common among patients with advanced kidney disease, particularly those requiring hemodialysis. Intravenous iron is a convenient treatment to supplement iron and is widely used among hemodialysis patients. Its efficacy is well established that, with treatment, hemoglobin levels rise and erythropoiesis-stimulating agent dose requirements are reduced. However, the safety of intravenous iron with respect to patient-centered outcomes has not been adequately studied. A variety of studies have indicated potential safety concerns, but most have been of small numbers of patients and with end points studied that have unclear clinical relevance. In this study, issues related to iron toxicity are reviewed.

Approaches to inverse-probability-of-treatment--weighted estimation with concurrent treatments

OBJECTIVES

In a setting with two concurrent treatments, inverse-probability-of-treatment weights can be used to estimate the joint treatment effects or the marginal effect of one treatment while taking the other to be a confounder. We explore these two approaches in a study of intravenous iron use in hemodialysis patients treated concurrently with epoetin alfa (EPO).

STUDY DESIGN AND SETTING

We linked US Renal Data System data with electronic health records (2004-2008) from a large dialysis provider. Using a retrospective cohort design with 776,203 records from 117,050 regular hemodialysis patients, we examined a composite outcome: mortality, myocardial infarction, or stroke.

RESULTS

With EPO as a joint treatment, inverse-probability-of-treatment weights were unstable, confidence intervals for treatment effects were wide, covariate balance was unsatisfactory, and the treatment and outcome models were sensitive to omission of the baseline EPO covariate. By handling EPO exposure as a confounder instead of a joint treatment, we derived stable weights and balanced treatment groups on measured covariates.

CONCLUSIONS

In settings with concurrent treatments, if only one treatment is of interest, then including the other in the treatment model as a confounder may result in more stable treatment effect estimates. Otherwise, extreme weights may necessitate additional analysis steps.

Diminution of 2,3,5-triphenyltetrazolium chloride toxicity on Listeria monocytogenes growth by iron source addition to the culture medium

Tetrazolium salts (TTZ) such as 2,3,5-triphenyltetrazolium chloride (TTC) are readily reduced by bacterial populations of various genus. The reduced form of these redox indicators is conspicuously colored allowing a quick and easy detection of growth. The studies are mainly confined to Gram negative bacteria because of an important toxic effect of tetrazolium salts on Gram positive bacteria. Indeed, we observed an important impact of different tetrazolium salts on Listeria monocytogenes growth, curiously limited to an increase in the duration of the lag phase. In this study, we demonstrate that increasing the iron concentration in a medium containing TTC leads to a significant decrease of the lag phase. L. monocytogenes growth was kinetically measured and growth parameters were estimated using the Baranyi model. While lag phase diminution was found to be iron concentration dependent, growth rate was not affected. Addition of iron enables growth of some strains totally inhibited by a 0.4 g/l of TTC and for the other a significant reduction of the latency is observed. The nature of the mechanism resulting in a decrease of the observed lag phase remains unclear. Then, the use of iron supplementation may be proposed to overcome the inhibitory effect of TTC on L. monocytogenes.

Infection risk with bolus versus maintenance iron supplementation in hemodialysis patients

Intravenous iron may promote bacterial growth and impair host defense, but the risk of infection associated with iron supplementation is not well defined. We conducted a retrospective cohort study of hemodialysis patients to compare the safety of bolus dosing, which provides a large amount of iron over a short period of time on an as-needed basis, with maintenance dosing, which provides smaller amounts of iron on a regular schedule to maintain iron repletion. Using clinical data from 117,050 patients of a large US dialysis provider merged with data from Medicare's ESRD program, we estimated the effects of iron dosing patterns during repeated 1-month exposure periods on risks of mortality and infection-related hospitalizations during the subsequent 3 months. Of 776,203 exposure/follow-up pairs, 13% involved bolus dosing, 49% involved maintenance dosing, and 38% did not include exposure to iron. Multivariable additive risk models found that patients receiving bolus versus maintenance iron were at increased risk of infection-related hospitalization (risk difference [RD], 25 additional events/1000 patient-years; 95% confidence interval [CI], 16 to 33) during follow-up. Risks were largest among patients with a catheter (RD, 73 events/1000 patient-years; 95% CI, 48 to 99) and a recent infection (RD, 57 events/1000 patient-years; 95% CI, 19 to 99). We also observed an association between bolus dosing and infection-related mortality. Compared with no iron, maintenance dosing did not associate with increased risks for adverse outcomes. These results suggest that maintenance iron supplementation may result in fewer infections than bolus dosing, particularly among patients with a catheter.

The comparative short-term effectiveness of iron dosing and formulations in US hemodialysis patients

BACKGROUND

Intravenous iron is used widely in hemodialysis, yet there are limited data on the effectiveness of contemporary dosing strategies or formulation type.

METHODS

We conducted a retrospective cohort study using data from the clinical database of a large dialysis provider (years 2004-2008) merged with administrative data from the US Renal Data System to compare the effects of intravenous iron use on anemia management. Dosing comparisons were bolus (consecutive doses ≥100 mg exceeding 600 mg during 1 month) versus maintenance (all other iron doses during the month); and high (>200 mg over 1 month) versus low dose (≤200 mg over 1 month). Formulation comparison was administration of ferric gluconate versus iron sucrose over 1 month. Outcomes were hemoglobin, epoetin dose, transferrin saturation, and serum ferritin during 6 weeks of follow-up.

RESULTS

We identified 117,050 patients for the dosing comparison, and 66,207 patients for the formulation comparison. Bolus dosing was associated with higher average adjusted hemoglobin (+0.23 g/dL; 95% confidence interval [CI], 0.21-0.26), transferrin saturation (+3.31%; 95% CI, 2.99-3.63), serum ferritin (+151 μg/L; 95% CI, 134.9-168.7), and lower average epoetin dose (-464 units; 95% CI, -583 to -343) compared with maintenance. Similar trends were observed with high-dose iron versus low-dose. Iron sucrose was associated with higher adjusted average hemoglobin (+0.16 g/dL; 95% CI, 0.12-0.19) versus ferric gluconate.

CONCLUSIONS

Strategies favoring large doses of intravenous iron or iron sucrose lead to improved measures of anemia management. These potential benefits should be weighed against risks, which currently remain incompletely characterized.

Pomegranate juice intake attenuates the increase in oxidative stress induced by intravenous iron during hemodialysis

The hemodialysis (HD) procedure induces oxidative stress (OS), which is further aggravated by intravenous (IV) iron administration, aimed at correcting anemia of patients with HD. We have recently shown that 1 year of pomegranate juice (PJ) intake attenuated OS and inflammation in patients with HD. In the current study, we hypothesized that a single dose of PJ can attenuate the enhanced OS and inflammation induced by both the dialysis procedure and IV iron administration during HD session. Twenty-seven patients with HD were randomized to receive PJ or placebo during 1 dialysis session with IV iron. Blood samples were drawn before and after the session to asses OS biomarkers such as advanced oxidation protein products and myeloperoxidase (MPO), whereas polymorphonuclear leukocyte (PMNL) counts served as an indirect measure of inflammation. At the end of the dialysis session, an increase in advanced oxidation protein products and MPO levels as well as a decrease in PMNLs counts were observed in the placebo group, whereas no significant changes occurred in the PJ group. The postdialysis increase in MPO levels in the placebo group is a direct result of PMNL degranulation, associated with postdialysis decrease in PMNL counts. Degranulation of PMNLs leads to the release of other cell moieties, such as inflammatory mediators and proteases that enhance inflammation. We conclude that PJ intake attenuated the increase in systemic OS and inflammation induced by IV iron administration during the dialysis session. These beneficial effects illuminate the previously observed attenuation in OS and inflammation in patients with HD on prolonged PJ intake.

Biodistribution and predictive hepatic gene expression of intravenous iron sucrose

INTRODUCTION

We have examined iron biodistribution and hepatic gene expression in rats following administration of the generic Iron Sucrose Azad (ISA) or the reference iron sucrose drug Venofer®.

METHODS

ISA and Venofer® were administered intravenously to normal, non-anemic, male rats at 15 mg/kg (a supra-therapeutic dose-level). To evaluate biodistribution, tissue iron levels were determined over 28 days for plasma, liver, spleen, bone marrow, heart, kidney, lung and stomach using a validated ICP-MS method. Hepatic gene expression was evaluated by microarray analysis of mRNA from samples taken 24 h after drug administration.

RESULTS

Iron concentration/time profiles for plasma and tissues were quantitatively similar for ISA and Venofer. Following administration, circulating iron levels briefly exceeded transferrin binding capacity and there was a transient increase in hepatic iron. Bone marrow iron levels remained elevated throughout the study. No increases in tissue iron levels were observed in the heart, stomach or lungs. Spleen iron levels increased over the course of the study in treated and control rats. Small, transient increases were recorded in the kidneys of treated rats. The effects of ISA and Venofer® on hepatic gene transcription were similar. Principal components analysis showed that there was no systematic effect of either treatment on transcriptional profiles. Only a small number of genes showed significant modulation of expression. No transcriptional pattern matches with toxicity pathways were found in the ToxFX database for either treatment. No modulation of key genes in apoptosis, inflammation or oxidative stress pathways was detected.

DISCUSSION

These findings demonstrated that the biodistribution of administered iron is essentially similar for Iron Sucrose Azad and Venofer®, that iron sucrose partitions predominantly into the liver, spleen and bone marrow, and that hepatic gene expression studies did not provide any evidence of toxicity in animals treated at a supra-therapeutic dose-level.

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.

Update in critical care for the nephrologist: transfusion in nonhemorrhaging critically ill patients

A growing number of guidelines and recommendations advocate a restrictive transfusion strategy. Strong evidence exists that a hemoglobin threshold of less than 7 g/dL conserves resources and may improve outcomes in critically ill patients and that platelet counts greater than 10,000/μL are well tolerated. Patients with coronary artery disease can be safely managed with a restrictive transfusion strategy, utilizing a hemoglobin threshold of less than 7 or 8 g/dL; a threshold of less than 8 g/dL can be applied to patients with acute coronary syndromes. In the absence of coagulopathy with bleeding or high risk for bleeding, plasma transfusion should be withheld. Complications from transfusion are significant and previously under-recognized immunologic complications pose a more serious threat than infections. Erythropoietin and iron administration do not reduce transfusion needs in the critically ill. Interventions to reduce blood loss and educate clinicians are successful in reducing transfusion requirements.

New rat models of iron sucrose-induced iron overload

The majority of murine models of iron sucrose-induced iron overload were carried out in adult subjects. This cannot reflect the high risk of iron overload in children who have an increased need for iron. In this study, we developed four experimental iron overload models in young rats using iron sucrose and evaluated different markers of iron overload, tissue oxidative stress and inflammation as its consequences. Iron overload was observed in all iron-treated rats, as evidenced by significant increases in serum iron indices, expression of liver hepcidin gene and total tissue iron content compared with control rats. We also showed that total tissue iron content was mainly associated with the dose of iron whereas serum iron indices depended essentially on the duration of iron administration. However, no differences in tissue inflammatory and antioxidant parameters from controls were observed. Furthermore, only rats exposed to daily iron injection at a dose of 75 mg/kg body weight for one week revealed a significant increase in lipid peroxidation in iron-treated rats compared with their controls. The present results suggest a correlation between iron overload levels and the dose of iron, as well as the duration and frequency of iron injection and confirm that iron sucrose may not play a crucial role in inflammation and oxidative stress. This study provides important information about iron sucrose-induced iron overload in rats and may be useful for iron sucrose therapy for iron deficiency anemia as well as for the prevention and diagnosis of iron sucrose-induced iron overload in pediatric patients.

Parenteral Iron Therapy in the Pediatric Patient

For more than 50 years, iron dextran has been the mainstay of parenteral iron therapy in the United States. In October 2009, the Food and Drug Administration expanded its existing black box warning that cautioned practitioners to administer a test dose first because of the risk of anaphylactic, often fatal adverse reactions. It further modified the warning, stating that fatal reactions can still occur even in patients who tolerated the test dose. As a result, health care providers have sought safer alternatives to parenteral iron dextran when oral iron repletion is not an option. The purpose of this review is to discuss the currently available formulations, with a focus on the needs of the pediatric patient, in whom there is limited experience in using products other than iron dextran.

Labile plasma iron generation after intravenous iron is time-dependent and transitory in patients undergoing chronic hemodialysis

Iron supplementation in hemodialysis patients is fundamental to erythropoiesis, but may cause harmful effects. We measured oxidative stress using labile plasma iron (LPI) after parenteral iron replacement in chronic hemodialysis patients. Intravenous iron saccharate (100 mg) was administered in patients undergoing chronic hemodialysis (N = 20). LPI was measured by an oxidant-sensitive fluorescent probe at the beginning of dialysis session (T0), at 10 min (T1), 20 min (T2), and 30 min (T3) after the infusion of iron and at the subsequent session; P < 0.05 was significant. The LPI values were significantly raised according to the time of administration and were transitory: -0.02 +/- 0.20 micromol/L at the beginning of the first session, 0.01 +/- 0.26 micromol/L at T0, 0.03 +/- 0.23 micromol/L at T1, 0.09 +/- 0.28 micromol/L at T2, 0.18 +/- 0.52 micromol/L at T3, and -0.02 +/- 0.16 micromol/L (P = 0.001 to 0.041) at the beginning of the second session. The LPI level in patients without iron supplementation was -0.06 +/- 0.16 micromol/L. Correlations of LPI according to time were T1, T2, and T3 vs. serum iron (P = 0.01, P = 0.007, and P = 0.0025, respectively), and T2 and T3 vs. transferrin saturation (P = 0.001 and P = 0.0003, respectively). LPI generation after intravenous saccharate administration is time-dependent and transitorily detected during hemodialysis. The LPI increment had a positive correlation to iron and transferrin saturation.

Cutaneous warts in children before and after renal transplantation

Cutaneous warts occur in 3.9-4.9% of children in the UK. The incidence is increased in organ transplant recipients and may be increased in patients with chronic kidney disease (CKD), since uraemia reduces the immune system's function. We surveyed the records from our CKD and renal transplant clinic to ensure patients with warts were identified and appropriately treated. Data were collected by questionnaire. The presence of warts, location, treatment, levels of pain and emotional upset were recorded. Nine of 49 (18.4%) pre-transplantation patients (33 male, median age 12.1 years) were currently suffering from warts compared with 17 of 60 (28.3%) post-transplantation patients (34 male, median age 13.9 years). A further 14 pre-transplantation and 16 post-transplantation patients had previously suffered from warts which had resolved. Forty-one patients had sought treatment for warts, mainly from primary care. Five patients, all having received transplants, were seen by a dermatologist. Self-rated levels of pain and emotional upset were generally low, apart from those of four adolescent patients who expressed significant emotional upset. We concluded that cutaneous warts are more common among CKD patients. Appropriate information and treatment are required before and after transplantation. The majority of warts can be treated in primary care, but selected patients with extensive warts that cause distress need early referral for dermatology opinion.

Anemia in renal disease: diagnosis and management

Chronic kidney disease (CKD) is a widespread health problem in the world and anemia is a common complication. Anemia conveys significant risk for cardiovascular disease, faster progression of renal failure and decreased quality of life. Patients with CKD can have anemia for many reasons, including but not invariably their renal insufficiency. These patients require a thorough evaluation to identify and correct causes of anemia other than erythropoietin deficiency. The mainstay of treatment of anemia secondary to CKD has become erythropoiesis-stimulating agents (ESAs). The use of ESAs does carry risks and these agents need to be used judiciously. Iron deficiency often co-exists in this population and must be evaluated and treated. Correction of iron deficiency can improve anemia and reduce ESA requirements. Partial, but not complete, correction of anemia is associated with improved outcomes in patients with CKD.