Does sarcoma occur in man after intramuscular iron?

Several factors influence the induction of sarcomas at the site of iron carbohydrate complex injection in high dosage, in animals. 1. Species specificity: tumours have been induced in rats, mice and hamsters but not in guinea pigs or dogs; 2. dose-response: a threshold dose may be defined and the yield of tumours increases with the dose; 3. the amount of residual iron at the injection site: the effect is a local oncogenesis; 4. the latent period relative to life span in the species: the probable latent period in man has been estimated to be 15-20 years. Since iron-dextran was introduced 22 years ago, nine malignancies in man allegedly related to iron-complex injection have been described in five reports during the period 1960-1977. A critical review of the information available on these cases suggests that in one case only is the data sufficiencyl strong to support the probability of iron-dextran induced sarcoma in man. Soft tissue tumours of the buttock are not rare: on the basis of this single case a causal relationship in man cannot yet be made.

Bone marrow iron and plasma ferritin in dialysed patients given intravenous iron-dextran

Bone marrow biopsies have been taken in 28 patients on or approaching maintenance haemodialysis before and after treatment with monthly intravenous iron-dextran (Imferon). Stainable marrow iron was compared with blood Hb, plasma ferritin, erythrocyte protoporphyrin and MCH levels at the time of biopsy, and with previous or subsequent responses to iron in terms of blood Hb and MCH. There was a positive correlation between bone marrow iron and plasma ferritin levels both before and after iron therapy. All the patients with excess marrow iron had high plasma ferritin. However, six patients with low or normal marrow iron also had high plasma ferritin, two of these before iron therapy was given. Seven of the eight patients with no detectable marrow iron had low plasma ferritin. Three of the 28 patients failed to respond to iron with an increased blood Hb. MCH increased in all patients studied during iron therapy. All but one of the patients with high plasma ferritin prior to iron therapy responded well to iron. Although a good correlation between plasma ferritin and marrow iron can be shown in dialysed patients given intravenous iron-dextran, a high plasma ferritin level in an individual patient should not by itself preclude iron therapy.

Safety and efficacy of total dose infusion of iron dextran in iron deficiency anaemia

AIMS

Intravenous iron is usually reserved for patients in whom oral administration has failed. Typically the calculated total dose is divided in to several fractions. Total dose infusion (TDI) of iron dextran is not commonly used due to the potential for serious side effects such as anaphylactic reactions.

METHODS

We identified 214 patients retrospectively, who were given TDI. Outcomes studied were: immediate side effects, improvement of haemoglobin and haematocrit.

RESULTS

The most frequent side effect of TDI was nausea with a rate of 2.2%. Headache, vomiting, chills and backache were seen in 1.1% of patients and about 0.5% of patients experienced fever and diarrhoea. No anaphylactic reaction was noted. Observed mean elevation of haematocrit was 5.3% and haemoglobin of 2.0 gm/dl (p < 0.0001).

CONCLUSION

TDI of iron dextran is a safe, potentially efficacious and convenient treatment in iron deficiency anaemia, in patients unresponsive or intolerant to oral iron.

Iron preloading aggravates nutritional steatohepatitis in rats by increasing apoptotic cell death

BACKGROUND/AIMS

High serum ferritin and liver iron concentrations were found in some patients with NASH, suggesting a role for iron as a co-factor that aggravates liver injury. The aim of this study is to investigate the effects of parenteral iron in a rat model of NASH induced by a methionine choline deficient diet (MCDD).

METHODS

Wistar rats were divided into 1 - Control, 2 - Iron (Fe), 3 - MCDD, 4 - MCDD&Fe groups. Iron dextran 100mg/kg was administered intra-muscularly in groups 2 and 4. All rats were fed MCDD, Groups 1 and 2 were supplied with choline and methionine. Blood and tissue samples were obtained after 4weeks.

RESULTS

The iron injection alone did not affect the liver whereas MCDD led to steatohepatitis. Iron worsened steatosis without any obvious effect on accompanying inflammation. It aggravated tissue injury by increasing apoptosis. Liver fibrosis was observed only in 3 out of 10 rats in the MCDD&Fe group.

CONCLUSIONS

Observation of liver fibrosis only in the MCDD&Fe group suggests that iron induced increase in apoptosis contributes to the development of fibrosis at an earlier time than expected.

Acute injury with intravenous iron and concerns regarding long-term safety

Intravenous iron is widely used to maintain adequate iron stores and prevent iron deficiency anemia in patients with chronic kidney disease, yet concerns remain about its long-term safety with respect to oxidative stress, kidney injury, and accelerated atherosclerosis, which are the subjects of this review. Three parenteral iron formulations are available for use in the United States: Iron dextran, iron gluconate, and iron sucrose. Iron dextran, especially the high molecular form, has been linked with anaphylactoid and anaphylactic reactions, and its use has been declining. A portion of intravenous iron preparations is redox-active, labile iron available for direct donation to transferrin. In vitro tests show that commonly available intravenous iron formulations have differing capacities to saturate transferrin directly: Iron gluconate > iron sucrose > iron dextran. Intravenous iron treatment produces oxidative stress, as demonstrated by increases in plasma levels of lipid peroxidation products (malondialdehyde), at a point that is much earlier than the time to peak concentration of catalytically active iron, suggesting a direct effect of iron sucrose on oxidative stress. Furthermore, iron sucrose infusion produces endothelial dysfunction that seems to peak earlier than the serum level of free iron. Intravenous iron sucrose infusion also has been shown to produce acute renal injury and inflammation as demonstrated by increased urinary albumin, enzyme (N-acetyl-beta-glucosaminidase), and cytokine (chemokine monocyte chemoattractant protein-1) excretions. Although the long-term dangers of intravenous iron are unproved, these data call for examination of effects of intravenous iron on the potential for long-term harm in patients with chronic kidney disease.

Slow intravenous iron administration does not aggravate oxidative stress and inflammatory biomarkers during hemodialysis: a comparative study between iron sucrose and iron dextran

BACKGROUND/AIMS

Fast intravenous (i.v.) iron administration during hemodialysis (HD) is associated with the augmentation of oxidative stress and the increase in inflammatory biomarkers, which are also induced by the hemodialysis procedure itself. The aim of this study was to investigate if slow i.v. iron administration would aggravate the status of oxidative stress and inflammatory biomarkers during a hemodialysis session.

METHODS

Twenty dialysis patients 30-92 years of age that were iron replete and had values for hemoglobin, transferrin saturation and serum ferritin among recommended goals were evaluated in three separate hemodialysis sessions. In the first session patients did not receive any iron treatment, whereas during the second and the third session patients received slow (60 min) i.v. infusions of 100 mg of iron sucrose and 100 mg of iron dextran, respectively. Blood samples were drawn before the hemodialysis session, 15 min after the end of iron administration and at the end of the hemodialysis session in all occasions, for the measurement of markers of oxidant stress (oxidized LDL and ischemia-modified albumin) and inflammation (high-sensitivity C-reactive protein, interleukin-6 and tumor necrosis factor-alpha).

RESULTS

Oxidized LDL was not significantly altered during hemodialysis and this pattern was similar between the three occasions studied. In contrast, ischemia-modified albumin was significantly increased and this effect was also not different between the net hemodialysis and the occasions of iron administration. High-sensitivity CRP, IL-6 and TNF-alpha were all significantly elevated during hemodialysis and again both types of iron administration did not produce significant changes in this pattern.

CONCLUSION

We did not find an increase in the markers of oxidation/inflammation studied, after slow i.v. iron administration during hemodialysis session.

Differential expression of stress-inducible proteins in chronic hepatic iron overload

INTRODUCTION

Oxidative stress can trigger a cellular stress response characterized by induction of antioxidants, acute phase reactants (APRs) and heat shock proteins (HSPs), which are presumed to play a role in limiting tissue damage. In rodents, hepatic iron overload causes oxidative stress that results in upregulation of antioxidant defenses with minimal progressive liver injury. The aim of this study was to determine whether iron overload modulates expression of other stress-responsive proteins such as APRs and HSPs that may confer protection against iron-induced damage in rodent liver.

METHODS

Male rats received repeated injections of iron dextran or dextran alone over a 6-month period. Hepatic transcript levels for a panel of APRs and HSPs were quantitated by real-time PCR and protein expression was evaluated by Western blot and immunohistochemistry.

RESULTS

Hepatic iron concentrations were increased >50-fold in the iron-loaded rats compared to controls. Iron loading resulted in striking increases in mRNAs for Hsp32 (heme oxygenase-1; 12-fold increase vs. controls) and metallothionein-1 and -2 (both increased approximately 6-fold). Transcripts for alpha1-acid glycoprotein, the major rat APR, were increased approximately 3-fold, while expression of other classical APRs was unaltered. Surprisingly, although mRNA levels for the HSPs were not altered by iron, the abundance of Hsp25, Hsp70 and Hsp90 proteins was uniformly reduced in the iron-loaded livers, as were levels of NAD(P)H:quinone oxidoreductase 1, an Hsp70 client protein.

CONCLUSIONS

Chronic iron administration elicits a unique pattern of stress protein expression. These alterations may modulate hepatic responses to iron overload, as well as other injury processes.

Comparison of Oxidative Stress Markers After Intravenous Administration of Iron Dextran, Sodium Ferric Gluconate, and Iron Sucrose in Patients Undergoing Hemodialysis

STUDY OBJECTIVE

To compare non-transferrin-bound iron and markers of oxidative stress after single intravenous doses of iron dextran, sodium ferric gluconate, and iron sucrose.

DESIGN

Prospective, open-label, crossover study.

SETTING

University-affiliated general clinical research center.

PATIENTS

Twelve ambulatory patients undergoing hemodialysis.

INTERVENTION

Patients received 100 mg of intravenous iron dextran, sodium ferric gluconate, and iron sucrose in random sequence, with a 2-week washout period between treatments.

MEASUREMENTS AND MAIN RESULTS

Serum samples for transferrin saturation, non-transferrin-bound iron, and malondialdehyde (MDA; marker of lipid peroxidation) were obtained before (baseline) and 30, 60, 120, and 360 minutes and 2 weeks after each iron infusion. A serum sample for hemeoxygenase-1 (HO-1) RNA was obtained at baseline and 360 minutes after infusion. Non-transferrin-bound iron values were significantly higher 30 minutes after administration of sodium ferric gluconate and iron sucrose compared with iron dextran (mean +/- SEM 10.1 +/- 2.2, 3.8 +/- 0.8, and 0.23 +/-0.1 microM, respectively, p<0.001 for sodium ferric gluconate vs iron dextran, p = 0.002 for iron sucrose vs iron dextran). A significant positive correlation was noted between transferrin saturation and the presence of non-transferrin-bound iron for sodium ferric gluconate and iron sucrose (r2 = 0.37 and 0.45, respectively, p<0.001) but not for iron dextran (r2 = 0.09). After sodium ferric gluconate, significantly more samples showed increases in MDA levels from baseline compared with iron sucrose and iron dextran (p = 0.006); these increased levels were associated with the presence of non-transferrin-bound iron, baseline transferrin saturation above 30%, baseline transferrin levels below 180 mg/dl, and ferritin levels above 500 ng/ml (p<0.05). However, only a transferrin level below 180 mg/dl was independently associated (odds ratio 4.8, 95% confidence interval 1.2-15.3).

CONCLUSION

Iron sucrose and sodium ferric gluconate were associated with greater non-transferrin-bound iron appearance compared with iron dextran. However, only sodium ferric gluconate showed significant increases in lipid peroxidation. The relationship between non-transferrin-bound iron from intravenous iron and oxidative stress warrants further exploration.

Treatment of iron deficiency anemia with intravenous iron preparations

OBJECTIVE

We aimed to determine the effects of intravenous iron therapy on blood parameters in pediatric patients who do not tolerate oral iron therapy for any reason.

PATIENTS AND METHODS

The patient group consisted of candidates for elective operations requiring blood transfusions in order to raise hemoglobin (Hb) concentrations rapidly and for whom oral iron administration is useless and compliance with long-term treatment is definitely impossible due to sociocultural factors. Sixty-two children were included in the study. Venous blood samples were taken at diagnosis, and after 1 week and 1, 2 and 3 months. Hb, hematocrit, erythrocyte indices (mean erythrocyte volume, mean erythrocyte Hb and mean erythrocyte Hb concentration), serum iron (SI) levels, iron binding capacity, transferrin receptor (CD71) and serum ferritin levels were measured. Iron sucrose was used as an intravenous iron preparation.

RESULTS

All children showed improvements in iron deficiency anemia. A statistically significant elevation occurred between the time of diagnosis and week 1 (p<0.05) in nearly all parameters. SI was raised until at least 1 month of therapy. There was no significant difference between transferrin receptors measured before and after the intravenous iron therapy. Ferritin did not exceed the values achieved in the 1st month. Mild side effects were encountered in only 8 (12.9%) patients. Treatment was not discontinued because of side effects in any case. The patients in the control group were given an oral form containing ferroglycine sulfate.

CONCLUSION

Intravenous iron therapy can replace oral therapy in patients whose blood parameters must be raised rapidly and in situations where oral iron administration would not be appropriate for any reason. However, reinforcement with oral iron therapy or additional intravenous doses would be appropriate.

The role of intravenous iron in cancer-related anemia

Patients with cancer may have an absolute or functional iron deficiency as a result of their disease or its treatment. These conditions can lead to an insufficient supply of iron for incorporation into erythrocytes during supportive care with erythropoiesis-stimulating proteins for chemotherapy. The use of supplemental iron therapy is well established in patients with chronic kidney disease and anemia, but less well studied in the oncology/hematology setting. Furthermore, the use of oral iron formulations in patients with cancer and anemia is limited by poor absorption in the duodenum, arduous dosing requirements (three times a day), and a high likelihood of gastrointestinal side effects. Two recent studies have shown that intravenous (i.v.) iron (iron dextran or ferric gluconate) increases the hematopoietic response rates in cancer patients who were receiving chemotherapy and treated with epoetin alfa (Procrit) for anemia. The effects on hemoglobin levels and measures of iron metabolism were notably greater with i.v. iron formulations than with oral iron formulations. The results from several ongoing trials of i.v. iron in patients treated with epoetin alfa or darbepoetin alfa (Aranesp) for chemotherapy-induced anemia should lead to a greater understanding of the role of i.v. iron supplementation in improving the hematopoietic responses in these patients.

Parenteral iron therapy: a single institution's experience over a 5-year period

Many patients require parenteral iron therapy for optimal correction of anemia, including cancer patients who require erythropoietic drugs. Available parenteral iron therapy options include iron dextran, iron gluconate, and iron sucrose. The purpose of this study is to summarize our institution's experience with parenteral iron therapy over a 5-year period, with a focus on comparative safety profiles. All patients receiving parenteral iron therapy over this period were included in the analysis. Chi-squared test and Fisher's exact test were used to compare the adverse event rates of each product. A total of 121 patients received 444 infusions of parenteral iron over this period. Iron dextran was the most commonly used product (85 patients) and iron sucrose was the least used (2 patients). Iron gluconate was used by 34 patients. Overall adverse event rates per patient with iron dextran and iron gluconate were 16.5% and 5.8%, respectively (P = .024). Premedication with diphenhydramine and acetaminophen before infusions of iron dextran reduced adverse event rates per infusion from 12.3% to 4.4% (P = .054). Test doses of iron dextran were used 88% of the time for initial infusions of iron dextran. All adverse events for all parenteral iron products were mild or moderate. There were no serious adverse events and no anaphylaxis was observed. Our results suggest that, if test doses and premedications are used, iron dextran is an acceptable product to treat iron deficiency.

Intravenous iron therapy: well-tolerated, yet not harmless

In the majority of patients with chronic renal failure, it is essential to substitute erythropoietic agents and iron to maintain a haemoglobin level above 11 g dL-1. Intravenous iron is more effective than oral iron. Substitution of intravenous iron is mainly performed using iron(III)-hydroxide-sucrose complex (iron sucrose) and iron(III)-sodium-gluconate in sucrose (iron gluconate), and is, in general, well-tolerated. Nonetheless, intravenous iron therapy has effects on endothelial cells, polymorphonuclear leucocytes and cytokines which are most likely related to non-transferrin bound labile iron. These effects suggest a role of iron in infection or atherosclerosis. Yet, not all available data support the association of iron with infection and atherosclerosis. A recent trial showed that iron sucrose is safe when given as treatment for iron deficiency or for maintenance of iron stores. Nevertheless, iron therapy should be handled with caution but its use should not be feared whenever indicated.

Magnetic characterisation of rat muscle tissues after subcutaneous iron dextran injection

Ex vivo freeze-dried rat muscle tissues, collected at different times t after a single dose of subcutaneously injected iron dextran, have been magnetically characterised. The AC susceptibility of the tissues shows an overall superparamagnetic behaviour and the dependence on t of, especially, the out-of-phase component is remarkably systematic despite the fact that each tissue originates in a different rat individual. The experiments show that the akaganéite (beta-FeOOH) nanoparticles contained in the injected drug are progressively degraded in the living tissue and, at times of the order of 1 month and for all the analysed rat individuals, converge to a magnetically well-defined species with much narrower magnetic activation energy distribution than iron dextran. Thorough transmission electron microscopy experiments of the same tissues indicate the presence of oxyhydroxide particles, whose size decreases for increasing t in agreement with the interpretation of the magnetic susceptibility. The conclusions drawn from the magnetic study do well correspond to the properties of the whole tissue since no biochemical extraction work has been done. The AC susceptibility appears to be a valuable and complementary tool in pharmacological studies of iron-containing drugs.

Hypersensitivity reactions and deaths associated with intravenous iron preparations

BACKGROUND

Parenteral iron therapy is an accepted adjunctive management of anaemia in kidney disease. Newer agents may have fewer severe hypersensitivity adverse events (AE) compared with iron dextrans (ID). The rate of type 1 AE to iron sucrose (IS) and sodium ferric gluconate (SFG) relative to ID is unclear. We used the US Food and Drug Administration's Freedom of Information (FOI) surveillance database to compare the type 1 AE profiles for the three intravenous iron preparations available in the United States.

METHODS

We tabulated reports received by the FOI database between January 1997 and September 2002, and calculated 100 mg dose equivalents for the treated population for each agent. We developed four clinical categories describing hypersensitivity AE (anaphylaxis, anaphylactoid reaction, urticaria and angioedema) and an algorithm describing anaphylaxis, for specific analyses.

RESULTS

All-event reporting rates were 29.2, 10.5 and 4.2 reports/million 100 mg dose equivalents, while all-fatal-event reporting rates were 1.4, 0.6 and 0.0 reports/million 100 mg dose equivalents for ID, SFG and IS, respectively. ID had the highest reporting rates in all four clinical categories and the anaphylaxis algorithm. SFG had intermediate reporting rates for urticaria, anaphylactoid reaction and the anaphylaxis algorithm, and a zero reporting rate for the anaphylaxis clinical category. IS had either the lowest or a zero reporting rate in all clinical categories/algorithm.

CONCLUSIONS

These findings confirm a higher risk for AE, especially serious type 1 reactions, with ID therapy than with newer intravenous iron products and also suggest that IS carries the lowest risk for hypersensitivity reactions.

Benchmarking iron dextran sensitivity: reactions requiring resuscitative medication in incident and prevalent patients

BACKGROUND

Reliable information on the incidence of severe reactions to iron dextran is limited. Administration of agents of resuscitation in acute anaphylaxis may serve as a marker to quantify life-threatening adverse drug reactions.

METHODS

To determine the incidence of the most serious reactions to intravenous (i.v.) iron dextran, we searched the Gambro Healthcare US medical database for evidence of same-day administration of both i.v. iron dextran and parenteral adrenaline, corticosteroids or antihistamines. We confirmed each case as an iron dextran sensitivity reaction by direct inquiry. We also determined the total reported number of suspected adverse iron dextran reactions.

RESULTS

During the 16 month study period, we determined that 1,066,099 doses of i.v. iron dextran were given to 48,509 patients, including 20,213 patients who had not previously received iron dextran (iron dextran naïve). We identified seven patients who experienced reactions requiring resuscitative agents, all in response to a test dose (five patients) or first therapeutic dose (two patients), and therefore all in the iron-naïve (incident) group. Thus, we found the incidence of iron dextran reactions requiring resuscitative agents to be 0.035% (7 out of 20,213). No reaction was fatal. In a combined group of incident and prevalent patients, we found 337 total reports of suspected adverse reactions to iron dextran, without regard to severity of reaction, yielding an overall per patient adverse drug event (ADE) rate of 0.69% (337 out of 48,509) and per exposure rate of 0.03% (337 out of 1,066,099).

CONCLUSIONS

The incidence of reactions to iron dextran requiring resuscitative medications, per exposure or per patient, is approximately 0.035%. Reactions of this severity occur after either the test dose or first dose of iron dextran.

Iron supplementation in adolescent hemodialysis patients

AIMS

Iron supplementation is necessary in children on hemodialysis, but the optimal protocol remains unknown. We studied the effects of changing our unit's protocol from oral iron with periodic doses of parenteral iron dextran to routine administration of parenteral sodium ferric gluconate on anemia and iron parameters.

METHODS

We followed seven hemodialysis patients aged 15 20 years (mean 17 years). Hemoglobin, hematocrit, serum iron, transferrin saturation, ferritin, erythropoietin dose, total elemental iron dose and total iron cost for the six months prior to the protocol change were compared to the same variables during the six months following the change.

RESULTS

There was no statistically significant difference between the doses of parenteral iron between the two protocols; however, the total dose of elemental iron administered in the oral iron plus iron dextran protocol was greater than in the sodium ferric gluconate protocol (19.6+/-13.1 (mean+/-SD) mg/kg/week versus 1.1+/-0.3 mg/kg/week; p = 0.03). Both protocols had equivalent efficacy with respect to hemoglobin, ferritin and other measures of iron stores. On the other hand, the costs of sodium ferric gluconate were significantly higher than those of oral iron plus intermittent iron dextran (157.75+/-45.94 $/patient/month versus 52.08+/-49.88 $/patient/month; p = 0.01).

CONCLUSIONS

Routine administration of sodium ferric gluconate is equivalent if not superior to use of oral iron plus iron dextran for maintenance of iron stores in adolescents on hemodialysis, but more expensive.

The treatment of restless legs syndrome with intravenous iron dextran

BACKGROUND AND PURPOSE

To evaluate the safety and efficacy of a single 1000 mg iron infusion in treating Restless Legs Syndrome (RLS).

PATIENTS AND METHODS

A single 1000 mg intravenous (IV) [Am J Med Sci 31 (1999) 213] infusion of iron dextran was evaluated in an open-label study. Primary outcomes of efficacy were symptom severity assessed by global rating scale and periodic leg movements in sleep (PLMS) at 2 weeks post-infusion. Secondary outcomes included total sleep time (TST), hours/day of RLS symptoms, and changes in magnetic resonance imaging (MRI)-determined iron concentrations in the substantia nigra. Primary safety measures were reported adverse events and monthly serum ferritin levels.

RESULTS

IV iron therapy significantly improved the mean global RLS symptom severity, TST, hours with RLS symptoms and PLMS, but on an individual basis failed to produce any response in 3 of the 10 subjects who were fully treated. Brian iron concentrations at 2 weeks post-infusion as determined by MRI were increased in the substantia nigra and prefrontal cortex. Serum ferritin levels showed a greater than predicted rapid linear decrease. Side effects were mild, except in one subject who developed an acute allergic reaction.

CONCLUSIONS

The results in this study provide valuable information for future studies, but the efficacy and safety of IV iron treatment for RLS remain to be established in double-blind studies. The serum ferritin results suggest that greater than expected iron loss occurs after IV iron loading.

Parenteral iron nephrotoxicity: Potential mechanisms and consequences1

BACKGROUND

Parenteral iron administration is a mainstay of anemia management in renal disease patients. However, concerns of potential iron toxicity persist. Thus, this study was conducted to more fully gauge iron toxicologic profiles and potential determinants thereof.

METHODS

Isolated mouse proximal tubule segments (PTS) or cultured proximal tubular [human kidney (HK-2)] cells were exposed to four representative iron preparations [iron sucrose (FeS), iron dextran (FeD), iron gluconate (FeG), or iron oligosaccharide (FeOS)] over a broad dosage range (0, 30 to 1000 microg iron/mL). Cell injury was assessed by lactate deyhdrogenase (LDH) release, adenosine triphosphate (ATP) reductions, cell cytochrome c efflux, and/or electron microscopy. In vivo toxicity (after 2 mg intravenous iron injections) was assessed by plasma/renal/cardiac lipid peroxidation [malondialdehyde (MDA)], renal ferritin (protein)/heme oxygenase-1 (HO-1) (mRNA) expression, electron microscopy, or postiron injection PTS susceptibility to attack.

RESULTS

In each test, iron evoked in vitro toxicity, but up to 30x differences in severity (e.g., ATP declines) were observed (FeS > FeG > FeD = FeOS). The in vitro differences paralleled degrees of cell (HK-2) iron uptake. In vivo correlates of iron toxicity included variable increases in renal MDA, ferritin, and HO-1 mRNA levels. Again, these changes appeared to parallel in vivo (glomerular) iron uptake (seen with FeS and FeG, but not with FeD or FeOS). Iron also effected in vivo alterations in proximal tubule cell homeostasis, as reflected by the "downstream" emergence of tubule resistance to in vitro oxidant attack.

CONCLUSION

Parenteral iron formulations have potent, but highly variable, cytotoxic potentials which appear to parallel degrees of cell iron uptake (FeS > FeG >> FeD or FeOS). That in vitro injury can be expressed at clinically relevant iron concentrations, and that in vivo glomerular iron deposition/injury may result, suggest caution is warranted if these agents are to be administered to patients with active renal disease.