Role of antioxidants on the erythrocytes resistance to lipid peroxidation after acute iron overload in rats

The Effects of Dietary Polyphenols on Circulating Cardiovascular Disease Biomarkers and Iron Status: A Systematic Review

The prevalence of cardiovascular disease (CVD) is rising worldwide, remaining the major cause of death in developed countries. Polyphenols have been shown to have cardioprotective properties; however, their impact on iron bioavailability and potential impact on other aspects of health is unclear. A systematic review was undertaken to evaluate the current status of the relationship between habitual polyphenol consumption, iron status, and circulating biomarkers of CVD. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2009 guidelines, searches were performed across 5 electronic databases (PubMed, Cochrane Library, Scopus, Web of Science, and CINAHL) to identify randomized controlled trials which investigated the effects of polyphenol consumption on inflammatory markers, serum lipid profile, and iron absorption and bioavailability. In total, 1174 records were identified, with only 7 studies meeting the inclusion criteria. The selected studies involved 133 participants and used a variety of foods and supplements, including olive oil and cherries, rich in polyphenols including hydroxytyrosol, quercetin, and resveratrol, as well as catechin enriched drinks. The duration of the studies ranged from between 56 and 145 days, with total polyphenolic content of the food items and supplements ranging from 45 to 1015 mg (per 100 g). Polyphenols did not appear to interfere with iron status, and most studies reported improvements in inflammatory markers and lipid profile. While these results are promising, the limited number of studies and considerable heterogeneity across the interventions support the need for more extensive trials assessing the relationship between polyphenol intake, iron bioavailability, and CVD risk.

Oral administration of cadmium depletes intratesticular and epididymal iron levels and inhibits lipid peroxidation in the testis and epididymis of adult rats

Cadmium (Cd)-induced tissue injury depends on the accumulated Cd which differentially affects endogenous iron (Fe). To investigate this, adult rats were treated by oral gavage with Cd (50 mg/kg body wt.) once a week for 15, 30 and 60 days and sacrificed a day after last administration. After the 15th and 30th day of treatment, Cd had no effect on thiobarbituric acid reactive substances (TBARS) and endogenous Fe levels but exhibited anti-androgenic effects (p < 0.05) and caused histological damages. At day 60, Cd was accumulated by 156.30% and 364.77% above control values at concentrations that decreased endogenous Fe levels by 46.41% and 50.31% in the testis and epididymis respectively. The histological damages were characterized by decreased tubular diameter, damage to the epithelium leading to loss of tubular germ cells and absent of spermatozoa in the epididymal lumen. Although myeloperoxidase activities were increased, TBARS levels were found to decrease significantly at day 60 in the serum, testis and epididymis suggesting that the histological damages were not caused by lipid peroxidation. Furthermore, TBARS correlated negatively with Cd in the testis (r = -0.251, p < 0.05) and epididymis (r = -0.286, p < 0.05); Fe correlated positively with TBARS in the testis (r = +0.217, p < 0.05) and Cd correlated negatively with Fe in the testis (r = -0.461, p < 0.05) and epididymis (r = -0.109, p < 0.05). The antioxidant enzymes, superoxide dismutase and glutathione peroxidase were also decreased in the gonads after 60 days Cd treatment. Overall, anti-androgenic effects and histo-pathological changes are early indicators of direct effects of Cd and occur before decrease in TBARS which is secondarily related to the modifying of Fe contents.

Methylene Blue Exerts Anticonvulsant and Neuroprotective Effects on Self-Sustaining Status Epilepticus (SSSE) Induced by Prolonged Basolateral Amygdala Stimulation in Wistar Rats

BACKGROUND This study was designed to investigate the potential anticonvulsant and neuroprotective effects of methylene blue (MB) on self-sustaining status epilepticus (SSSE) induced by prolonged basolateral amygdala stimulation (BLA) in Wistar rats. MATERIAL AND METHODS The rats were randomly divided into 4 groups: (1) the Control group (rats without any treatment); (2) the Sham group (rats received electrode implantation but without electrical stimulation); (3) the SSSE group (rats received electrode implantation and additional electrical stimulation); and (4) the SSSE+MB group (rats received 1 mg/kg MB intraperitoneal injection 5 min after SSSE). SSSE models were established by prolonged BLA stimulation. The severities of SSSE were assessed by the number of separate seizures and the accumulated time of seizures. The variations of malondialdehyde/glutathione (MDA/GSH) were assessed 24 h after the establishment of SSSE. Nissl staining was performed to detect the surviving neurons in hippocampal CA1 and CA3 regions, and Western blotting assays were used to detect Caspase-3 (CASP3), B cell lymphoma 2 (BCL2), and BCL2-associated X protein (BAX). RESULTS Compared with the SSSE group, treatment with MB (1) markedly reduced the number and accumulated time of seizure activities; (2) significantly attenuated the increase of MDA and the decrease of GSH hippocampal levels; (3) markedly improved the cell morphology and alleviated the neuronal loss in hippocampal CA1 and CA3 regions; (4) significantly attenuated the increase of CASP3 and BAX and the decrease of BCL2 hippocampal levels. CONCLUSIONS MB has a protective effect in the SSSE model and may be useful as an adjuvant for preventing or treating epilepsy in humans.

The Anticonvulsant and Neuroprotective Effects of Oxysophocarpine on Pilocarpine-Induced Convulsions in Adult Male Mice

Epilepsy is one of the prevalent and major neurological disorders, and approximately one-third of the individuals with epilepsy experience seizures that do not respond well to available medications. We investigated whether oxysophocarpine (OSC) had anticonvulsant and neuroprotective property in the pilocarpine (PILO)-treated mice. Thirty minutes prior to the PILO injection, the mice were administrated with OSC (20, 40, and 80 mg/kg) once. Seizures and electroencephalography (EEG) were observed, and then the mice were killed for Nissl and Fluoro-jade B (FJB) staining. The oxidative stress was measured at 24 h after convulsion. Western blot analysis was used to examine the expressions of the Bax, Bcl-2, and Caspase-3. In this study, we found that pretreatment with OSC (40, 80 mg/kg) significantly delayed the onset of the first convulsion and status epilepticus (SE) and reduced the incidence of SE and mortality. Analysis of EEG recordings revealed that OSC (40, 80 mg/kg) significantly reduced epileptiform discharges. Furthermore, Nissl and FJB staining showed that OSC (40, 80 mg/kg) attenuated the neuronal cell loss and degeneration in hippocampus. In addition, OSC (40, 80 mg/kg) attenuated the changes in the levels of Malondialdehyde (MDA) and strengthened glutathione peroxidase and catalase activity in the hippocampus. Western blot analysis showed that OSC (40, 80 mg/kg) significantly decreased the expressions of Bax, Caspase-3 and increased the expression of Bcl-2. Collectively, the findings of this study indicated that OSC exerted anticonvulsant and neuroprotective effects on PILO-treated mice. The beneficial effects should encourage further studies to investigate OSC as an adjuvant in epilepsy, both to prevent seizures and to protect neurons in brain.

Iron, oxidative stress and gestational diabetes

Both iron deficiency and hyperglycemia are highly prevalent globally for pregnant women. Iron supplementation is recommended during pregnancy to control iron deficiency. The purposes of the review are to assess the oxidative effects of iron supplementation and the potential relationship between iron nutrition and gestational diabetes. High doses of iron (~relative to 60 mg or more daily for adult humans) can induce lipid peroxidation in vitro and in animal studies. Pharmaceutical doses of iron supplements (e.g., 10× RDA or more for oral supplements or direct iron supplementation via injection or addition to the cell culture medium) for a short or long duration will induce DNA damage. Higher heme-iron intake or iron status measured by various biomarkers, especially serum ferritin, might contribute to greater risk of gestational diabetes, which may be mediated by iron oxidative stress though lipid oxidation and/or DNA damage. However, information is lacking about the effect of low dose iron supplementation (≤60 mg daily) on lipid peroxidation, DNA damage and gestational diabetes. Randomized trials of low-dose iron supplementation (≤60 mg daily) for pregnant women are warranted to test the relationship between iron oxidative stress and insulin resistance/gestational diabetes, especially for iron-replete women.

Acute iron overload and oxidative stress in brain

An in vivo model in rat was developed by intraperitoneally administration of Fe-dextran to study oxidative stress triggered by Fe-overload in rat brain. Total Fe levels, as well as the labile iron pool (LIP) concentration, in brain from rats subjected to Fe-overload were markedly increased over control values, 6h after Fe administration. In this in vivo Fe overload model, the ascorbyl (A)/ascorbate (AH(-)) ratio, taken as oxidative stress index, was assessed. The A/AH(-) ratio in brain was significantly higher in Fe-dextran group, in relation to values in control rats. Brain lipid peroxidation indexes, thiobarbituric acid reactive substances (TBARS) generation rate and lipid radical (LR) content detected by Electron Paramagnetic Resonance (EPR), in Fe-dextran supplemented rats were similar to control values. However, values of nuclear factor-kappaB deoxyribonucleic acid (NFκB DNA) binding activity were significantly increased (30%) after 8h of Fe administration, and catalase (CAT) activity was significantly enhanced (62%) 21h after Fe administration. Significant enhancements in Fe content in cortex (2.4 fold), hippocampus (1.6 fold) and striatum (2.9 fold), were found at 6h after Fe administration. CAT activity was significantly increased after 8h of Fe administration in cortex, hippocampus and striatum (1.4 fold, 86, and 47%, respectively). Fe response in the whole brain seems to lead to enhanced NF-κB DNA binding activity, which may contribute to limit oxygen reactive species-dependent damage by effects on the antioxidant enzyme CAT activity. Moreover, data shown here clearly indicate that even though Fe increased in several isolated brain areas, this parameter was more drastically enhanced in striatum than in cortex and hippocampus. However, comparison among the net increase in LR generation rate, in different brain areas, showed enhancements in cortex lipid peroxidation, without changes in striatum and hippocampus LR generation rate after 6h of Fe overload. This information has potential clinical relevance, as it could be the key to understand specific brain damage occurring in conditions of Fe overload.

How a calculated oxidative stress can yield multiple therapeutic effects

It is proposed to discuss how ozonetherapy acts on patients affected by vascular and degenerative diseases. Ozone is a strong oxidant but, if used in small dosages on human blood ex vivo, acts as an acceptable stressor. By instantly reacting with PUFA bound to albumin, ozone is entirely consumed but generates two messengers acting in an early and in a late phase: the former is due to hydrogen peroxide, which triggers biochemical pathways on blood cells and the latter is due to alkenals which are infused into the donor patient. After undergoing a partial catabolism, alkenals enter into a great number of body's cells, where they react with Nrf2-Keap1 protein: the transfer of activated Nrf2 into the nucleus and its binding to antioxidant response element (ARE) is the crucial event able to upregulate the synthesis of antioxidant proteins, phase II enzymes and HO-1. With the progress of ozonetherapy, these protective enzymes are able to reverse the oxidative stress induced by chronic inflammation. Consequently, the repetition of graduated stresses induces a multiform adaptive response able to block the progress of the disease and to improve the quality of life.

Leukocyte DNA damage in children with iron deficiency anemia: effect of iron supplementation

Iron deficiency is frequently associated with anemia. Iron is a transition-metal ion, and it can induce free radical formation, which leads to formation of various lesions in DNA, proteins, and lipids. The aim of this study was to investigate baseline oxidative DNA damage and to clarify the role of the administration of a therapeutic dose of iron on DNA oxidation in children with iron deficiency anemia (IDA). Twenty-seven children with IDA and 20 healthy children were enrolled in the study. Leukocyte DNA damage (strand breaks and Fpg-sensitive sites) was assessed using comet assay before and after 12 weeks of daily iron administration. Before the iron administration, the frequency of DNA strand breaks in the children with IDA was found to be lower than those in the control group (P < 0.05), but there was not a significant difference for frequency of Fpg-sensitive sites. After 12 weeks of iron administration, the frequency of both DNA strand breaks and Fpg-sensitive sites were found to be increased (P < 0.01). No significant association was determined between DNA damage parameters and hemoglobin, hematocrit, serum iron, total iron binding capacity, and ferritin. In conclusion, basal level of DNA strand breaks is at a low level in children with IDA. After iron administration, DNA strand breaks and Fpg-sensitive sites, which represent oxidatively damaged DNA, increased. However, this increase was unrelated to serum level of iron and ferritin.

The ozone paradox: ozone is a strong oxidant as well as a medical drug

After five decades characterized by empiricism and several pitfalls, some of the basic mechanisms of action of ozone in pulmonary toxicology and in medicine have been clarified. The present knowledge allows to understand the prolonged inhalation of ozone can be very deleterious first for the lungs and successively for the whole organism. On the other hand, a small ozone dose well calibrated against the potent antioxidant capacity of blood can trigger several useful biochemical mechanisms and reactivate the antioxidant system. In detail, firstly ex vivo and second during the infusion of ozonated blood into the donor, the ozone therapy approach involves blood cells and the endothelium, which by transferring the ozone messengers to billions of cells will generate a therapeutic effect. Thus, in spite of a common prejudice, single ozone doses can be therapeutically used in selected human diseases without any toxicity or side effects. Moreover, the versatility and amplitude of beneficial effect of ozone applications have become evident in orthopedics, cutaneous, and mucosal infections as well as in dentistry.

Anemia and anemia correction: surrogate markers or causes of morbidity in chronic kidney disease?

Observational studies have shown a strong positive correlation between the severity of anemia and the risk of poor outcomes in patients with chronic kidney disease (CKD). This observation was initially taken to imply that adverse outcomes in CKD are caused by anemia. However, the assumption of causality ignores the possibility that anemia and adverse outcomes might be unrelated and that both are caused by underlying inflammation, oxidative stress and comorbid conditions. Randomized clinical trials of anemia correction have revealed an increased risk of adverse cardiovascular outcomes in patients assigned to normal, rather than subnormal, hemoglobin targets. As a result, correction of anemia is now considered potentially hazardous in patients with CKD. Notably, individuals who did not reach the target hemoglobin level in the clinical trials, despite receiving high doses of erythropoietin and iron, experienced a disproportionately large share of the adverse outcomes. These observations point to overdose of erythropoietin and iron, rather than anemia correction per se, as the likely culprit. This Review explores the reasons for the apparent contradiction between the findings of observational studies and randomized clinical trials of anemia treatment in CKD. I have focused on data from basic and translational studies, which are often overlooked in the design and interpretation of clinical studies and in the formulation of clinical guidelines.

Daily Supplementation with Iron Increases Lipid Peroxidation in Young Women with Low Iron Stores

The aim of this study was to determine whether women with low iron stores (plasma ferritin ≤ 20 μg/L) receiving a daily iron supplement for 8 wks at a level commonly used to treat poor iron status develop increased lipid peroxidation as measured by ethane exhalation rates and plasma malondialdehyde. The women served as their own control as pre- and post-supplementation periods were compared. Twelve women participated in the study for a 70-day period and consumed daily iron supplements (98 mg of iron as ferrous sulfate) from day 14 to day 70. Baseline blood and expired air samples were obtained on days 1 and 14; measurements during supplementation were performed on days 56 and 70, that is at 6 and 8 weeks of supplementation. Iron status improved during the iron supplementation period; biochemical indicators of lipid peroxidation also increased. After 6 wks of iron supplementation, serum ferritin almost doubled and body iron more than doubled. Hemoglobin levels increased slightly and other indicators of iron status became normal. However, plasma malondialdehyde (MDA) and breath ethane exhalation rates (BEER) increased by more than 40% between baseline and 6 wks of supplementation; these increases correlated significantly with plasma iron and ferritin levels. MDA was positively correlated with BEER. BEER increased further after 8 wks of iron supplementation. The increased indicators of lipid peroxidation with duration of supplementation and as iron status improved suggest that providing daily nearly 100 mg iron may not be a totally innocuous regimen for correcting iron depletion in women.

A physicochemical investigation on the effects of ozone on blood

Ozonation of either human whole blood or saline-washed erythrocytes causes considerable damage to the latter and this result has opened a controversy. With the benefit of hindsight, it appears logical that once erythrocytes are deprived of the potent antioxidants of plasma, they become very sensitive to the oxidant effects of ozone. The aim of the present work was to perform a physical-chemical evaluation of some critical parameters able to clarify this issue. We have ascertained that when whole blood is exposed to the appropriate ozone doses used in human therapy, no damage ensues while saline-washed erythrocytes undergo conspicuous haemolysis. The dogma that ozone is always toxic is incorrect because its reactivity below the concentration of 80mug/mL can be controlled by the plasmatic antioxidant system.

Effects of triiodothyronine-induced hyperthyroidism on lipid peroxidation, erythrocyte resistance and iron-binding and iron-oxidizing antioxidant properties of plasma in the rabbit

The effect of hyperthyroidism on some oxidative stress parameters is reported. The hyperthyroid state was induced by intraperitoneal injection of triiodothyronine (T3)(10 microg/kg body weight) for 14 days in two groups of female rabbits (3 and 12 months old). The T3 injection caused increase by 1.5-fold to 1.7-fold in T3 serum level, and 2-fold to 3-fold decrease (age-dependent) in body weight gain at the end of experimental period. The induced hyperthyroidism caused a significant increase in the serum concentration of the lipid peroxidation end-product malondialdehyde and lowered erythrocyte resistance to oxidative stress when subjected to the free radical generator 2,2'-azobis(2-amidinopropane) hydrochloride in vitro. The half maximum haemolysis time (HT50) decreased in the both experimental groups of rabbits, by about 12 min in the 3-month-old animals and 27 min in the 12-month-old animals. The study showed for the first time that hyperthyroidism enhances the ability of plasma to protect against iron-binding and iron oxidizing organic radicals. The scavenging property and antioxidant capacity of plasma against iron-binding inorganic radicals also increased. Measurement of erythrocyte resistance to oxidative stress and the protective ability of plasma against oxygen radicals discriminates the thyroid hormone modulatory effects in defence mechanisms against lipid peroxidation.

Iron, oxidative stress and human health

The amount of iron within the cell is carefully regulated in order to provide an adequate level of the micronutrient while preventing its accumulation to toxic levels. Iron excess is believed to generate oxidative stress, understood as an increase in the steady state concentration of oxygen radical intermediates. The main aspects of cellular metabolism of iron, with special emphasis on the role of iron with respect to oxidative damage to lipid membranes, are briefly reviewed here. Both in vitro and in vivo models are examined. Finally, a discussion of iron overload and its impact on human health is included. Overall, further studies are required to assess more effective means to limit iron-dependent damage, by minimizing the formation and release of free radicals in tissues when the cellular iron steady state concentration is increased either as a consequence of disease or by therapeutic iron supplementation.

Oxidative stress in the hippocampus after pilocarpine-induced status epilepticus in Wistar rats

The role of oxidative stress in pilocarpine-induced status epilepticus was investigated by measuring lipid peroxidation level, nitrite content, GSH concentration, and superoxide dismutase and catalase activities in the hippocampus of Wistar rats. The control group was subcutaneously injected with 0.9% saline. The experimental group received pilocarpine (400 mg.kg(-1), subcutaneous). Both groups were killed 24 h after treatment. After the induction of status epilepticus, there were significant increases (77% and 51%, respectively) in lipid peroxidation and nitrite concentration, but a 55% decrease in GSH content. Catalase activity was augmented 88%, but superoxide dismutase activity remained unaltered. These results show evidence of neuronal damage in the hippocampus due to a decrease in GSH concentration and an increase in lipid peroxidation and nitrite content. GSH and catalase activity are involved in mechanisms responsible for eliminating oxygen free radicals during the establishment of status epilepticus in the hippocampus. In contrast, no correlations between superoxide dismutase and catalase activities were observed. Our results suggest that GSH and catalase activity play an antioxidant role in the hippocampus during status epilepticus.

Ozone as Janus: this controversial gas can be either toxic or medically useful

Ozone is an intrinsically toxic gas and its hazardous employment has led to a poor consideration of ozone therapy. The aim of this review is to indicate that a wrong dogma and several misconceptions thwart progress: in reality, properly performed ozone therapy, carried out by expert physicians, can be very useful when orthodox medicine appears inadequate. The unbelievable versatility of ozone therapy is due to the cascade of ozone-derived compounds able to act on several targets leading to a multifactorial correction of a pathological state. During the past decade, contrary to all expectations, it has been demonstrated that the judicious application of ozone in chronic infectious diseases, vasculopathies, orthopedics and even dentistry has yielded such striking results that it is deplorable that the medical establishment continues to ignore ozone therapy.

In vivo and in vitro antioxidant properties of furosemide

The aim of this study was to investigate in vivo and in vitro antioxidant properties of furosemide. In vitro, human red blood cells were submitted to oxidative stress (AAPH), in absence or in presence of different concentrations of furosemide. Potassium efflux was measured in order to quantify the oxidative stress after the action of AAPH on red blood cells. Allophycocyanin assay was also used to investigate antioxidant capacities of furosemide. For the in vivo experiment, male Wistar rats were used. A control group (n = 5) was treated by a daily intraperitoneal injection of saline solution (0.2 ml); 2 other groups (J0 and J+) were treated for 7 days by one daily intraperitoneal injection of furosemide (0.10 mg/kg/day). In the J+group, the injection of furosemide was done one hour before the experiment, while in the J0 group the last injection of furosemide was done on the 6th day and an injection of saline was performed one hour before the experiment. On the day of experiment, a laparotomy was performed under general anesthesia and blood was collected from abdominal aorta. Oxidative stress and antioxidant capacities were evaluated on Wistar rat red blood cells and plasma. In vitro results (oxidative challenge with AAPH) showed that oxidative stress was decreased in presence of furosemide. This was due to a potent free radical scavenging effect of furosemide. In vivo studies confirmed that furosemide had antioxidant properties. These data may be of great relevance in clinical practice, considering the use of large doses of furosemide in patients presenting pathology involving the production of free radicals.

Species differences in the susceptibility of erythrocytes exposed to free radicals in vitro

The susceptibility of human, cow, pig, sheep and rabbit erythrocytes to free radicals (peroxyl radicals) generated in vitro by 2,2'-azo-bis(2-amidinopropane) hydrochloride (AAPH) was evaluated by means of a haemolysis test and expressed as the time to 50% of maximal haemolysis (HT50). The most sensitive to damage by free radicals appeared to be the erythrocytes of pigs and sheep, their HT50 values being (mean +/- SEM) 85.1 +/- 1.28 min and 89.0 +/- 1.31 min, respectively. Human erythrocytes and those of cows and rabbits were about twice as resistant, their HT50 values being (mean +/- SEM) 174.3 +/- 1.53 min, 181.2 +/- 1.22 min and 183.4 +/- 2.54 min, respectively. Pig and sheep erythrocytes used in the haemolysis test provided an indication of the antioxidant status in a shorter time (2.5 h versus 4.5 h) than those of the other species studied. The results indicate that the HT50 test may be a convenient alternative to the osmotic resistance test for defining the antioxidant resistance of erythrocytes.

Lidocaine inhibits potassium efflux and hemolysis in erythrocytes during oxidative stress in vitro

Lidocaine is a widely used local anesthetic agent. The aim of this work was to study the action of lidocaine on human red blood cells exposed to an oxidative stress in vitro. Blood was obtained from healthy volunteers. After separation from plasma, the erythrocytes were suspended in phosphate buffer. Oxidative stress was induced by incubation with a free radical generator, the 2,2' azobis (2-amidinopropane) hydrochloride (AAPH). Erythrocytes were incubated with or without lidocaine at two concentrations (36.93 and 73.85 microM) and with or without AAPH (20 mM). Electron paramagnetic resonance (EPR) spectroscopy was performed to identify the free radical species generated by AAPH using the spin trap 5-5'-dimethyl-L-pyroline-N-oxide (DMPO). Different sets of experiments were run. Potassium efflux was measured by flame photometry in each group at time 0 min and every 30 min of the experiment for 2 h. Hemolysis was studied by the Drabkin method at increasing concentrations of AAPH (20, 50, and 100 mM) and with or without lidocaine (36.93 microM). The oxygen radical absorbance capacity (ORAC) was measured by using allophycocyanin (APC) as a fluorescent indicator protein, and the antioxidant capacity of lidocaine (36.93 microM) was studied by the analysis of fluorescence of the APC. AAPH was shown to produce alkoxyl free radicals. Oxidative stress induced a marked increase in the potassium efflux and the hemolysis that was AAPH dose-dependent. Lidocaine inhibited the potassium efflux and delayed the occurrence of hemolysis. Lidocaine did not show any antioxidant properties for the free radical species generated by AAPH. In this model, lidocaine protects erythrocytes against oxidative stress. This effect is not explained by a free radical scavenging property. The results may be of great interest in clinical practice such as intravenous regional anesthesia or the prevention of ischemia-reperfusion injury.

Hypotransferrinemia of chronically hemodialyzed patients

Increasingly, the iron needs of hemodialysis patients receiving erythropoietin are being met by infusions of intravenous iron guided by laboratory tests to measure body iron availability. The interpretation of assays based on ferritin and transferrin must take into account the effect of inflammation on both proteins and malnutrition on the latter. In our chronic hemodialysis population, hypotransferrinemia was present in greater than 90% of the patients. Using statistical methods and laboratory studies, we sought to identify the principal reasons for the high prevalence of hypotransferrinemia. We observed that transferrin levels were disproportionately low relative to albumin and prealbumin and correlated inversely with ferritin levels. There was no correlation between transferrin and the soluble transferrin receptor. After the infusion of 900 mg of iron, transferrin saturation increased and total transferrin decreased so that unsaturated iron bonding capacity decreased as well. Ferritin concentrations increased significantly after iron loading. Attempts to demonstrate activation of the patients' antioxidant mechanisms associated with iron infusion were negative. We concluded that the low transferrin may be principally the result of diminished synthesis related to the chronic inflammatory status of hemodialysis patients, which favors production of ferritin, but iron and nutritional status may also influence the blood transferrin concentration. These factors make interpretation of transferrin-dependent assessment of body iron stores unreliable and can result in inadequate or overly aggressive iron-replacement therapy.