Iron Deficiency State Research Articles

Use of isotopes in the diagnosis of hematopoietic disorders

Isotopes of iron have been paramount in clinical tracer studies of hematopoiesis. Kinetics of disappearance from plasma, appearance in circulating erythrocytes, and localization in general areas of bone marrow, spleen, and liver were early revealed by gamma-/beta-emitting Fe-59 with note of characteristic differences of kind and degree of dysfunction among various anemias. Findings have helped in management (e.g., decisions about splenectomy). Positron/gamma-emitting Fe-52 (better for imaging) has provided more detail on marrow expansion and erythropoietic relocation. Other gamma-emitting tracers of hematopoiesis have been In-111 (linked to transferrin) and technetium 99m (Tc-99m) colloids (localizing to reticuloendothelial cells, which have close association with blood cell progenitors), but Fe-52 has proved to be more accurate for recognition of erythropoiesis. Occasional diverse heterotopic sites of hematopoiesis beyond spleen and liver in states of bone marrow disease have posed diagnostic challenges and also raised questions about migration and/or activation of stem cells. Studies of granulopoiesis utilize Tc-99m--labeled leukocytes or Tc99m-labeled antibodies to circulating and progenitor white cells. Iron-deficiency anemias due to malnutrition, malabsorption, blood loss, or special need are explored by dual study (oral vs intravenous) with radioactive (Fe-59, Fe-55) or stable (Fe-54, Fe-57) iron isotopes, which can guide dietary supplementation. Tests for B-12 deficiency in pernicious anemia or malabsorption with radioisotopes of cobalt (Co-57, Co-58) have been upgraded in sensitivity and scope. Rates of oxidation to expired carbon dioxide from particular carbon (radioactive C-14 or stable C-13)--labeled compounds can test B-12 or folic acid deficiencies or gastric infestation as causes of megaloblastic anemias.

Efficacy of Tokishakuyakusan on the Anemia in the Iron-Deficient Pregnant Rats

Iron-deficiency anemia not only causes insufficient oxygen delivery to the body of the mother, but creates serious conditions in the fetus, such as insufficient oxygen delivery and poor development, and its treatment has become an important issue. To elucidate the mechanism of the anemia-ameliorating action of Tokishakuyakusan, we investigated the effect of administration of Tokishakuyakusan on anemia-related parameters and the serum transferrin and erythropoietin levels, erythrocyte morphology, and bone marrow cells in pregnant rats and in pregnant rats with iron-deficiency anemia. The results showed that Tokishakuyakusan significantly improved the low erythrocyte count, hemoglobin, and hematocrit values of the pregnant rats in the iron-deficient state, increased the proportion of normal erythrocytes in terms of erythrocyte morphology, increased the proportion of erythroblasts among bone marrow cells, and also significantly increased the erythropoietin and transferrin levels in the blood. These findings suggested that Tokishakuyakusan promotes erythrocyte differentiation in iron-deficiency anemia, and that it possesses anemia-ameliorating efficacy.

Liver and Iron Metabolism - A Comprehensive Hypothesis for the Pathogenesis of Genetic Hemochromatosis

It is hypothesized that a homozygous C282Y mutation of the HFE gene prohibits the assembly of the transferrin-receptor 1 (TFR1) with the divalent metal transporter (DMT1) as the main iron update complex in hepatocytes membrane. Thus, the cellular influx of transferrin-bound iron from the endosomal compartment into the cytasol is compromised. As a consequence, transferrin saturation increases while concomitantly a cytosolic iron deficiency state develops. This in turn triggers the suppression of hepcidin synthesis in hepatocytes. Its impaired release into the bloodstream, causes the increased intestinal iron absorption of hemochromatosis. Excessively absorbed iron cannot be used by the erythron as a surplus for hemoglobin synthesis and is therefore trapped in ferritin complexes of RES macrophages. The ferritin is thereafter released into the bloodstream and taken up by hepatocytes for final disposal. In the lysosomal compartment ferritin is degraded to hemosiderin. Here, the release of excessive iron molecules may induce cellular injury via free radicals. The phenotypic expression of genetic hemochromatosis may depend on the activity of the erythron to use transferrin-bound-iron for heme synthesis. Therefore, a high erythron requirement for iron can utilize excess iron and may represent the rationale of phlebotomy therapy in this disease.

Serum Transferrin Receptor in Children: Usefulness for Determinating the Nature of Anemia in Infection

To know the variations of serum transferrin receptor (sTfR) and its indices depending on the status of body iron and the presence of infection in children, to evaluate their usefulness for recognizing the nature of anemia in infection, and to know the role of erythropoietic activity in these conditions. Three hundred and sixty-eight children between 1 and 10 years were included: 206 healthy children; 60 iron deficient anemic children (IDA); 102 with anemia and infectious disease, 58 of them meeting criteria for IDA. We measured hemoglobin, red cell indices, reticulocytes, transferrin saturation, serum ferritin, erythrocyte protoporphyrin, serum erythropoietin, and sTfR. Statistic method: ANOVA test, multiple linear regression, and ROC curve. sTfR, sTfR/ferritin ratio, and sTfR-logferritin index values were found to increase significantly in IDA children. These values were significantly lower in infectious anemia than iron deficiency states. Serum erythropoietin only was elevated significantly in iron deficiency states. In children without infection, mean corpuscular hemoglobin, erythrocyte protoporphirin, erythropoietin logarithm, and total-iron-binding-capacity logarithm predicted 81% of sTfR variability. sTfR and its indices showed a very high sensitivity and specificity for recognizing iron deficiency states. In children with IDA and infection sensitivity for sTfR/ferritin ratio was low (area under the curve: 0.71; 95% confidence interval: 0.64-0.88). For discriminating the nature of anemia in infection the cut-off point obtained for sTfR, sTfR/ferritin ratio, and sTfR-F index were 3, 70, and 1.8, respectively, and their sensitivity and specificity were also very high. sTfR, sTfR/ferritin ratio, and sTfR-F index are useful parameters for recognizing iron deficiency and the nature of anemia in infection. In IDA+infection, sTfR/ferritin ratio should not be recommended in the diagnosis of iron deficiency. In iron deficiency, erythropoietic activity has a secondary role as predictor factor of sTfR levels.

Biochemical Markers of Iron Status Are of Limited Value in the Diagnosis of Iron Deficiency Associated with Anemia of Chronic Disease.

Various laboratory parameters are used to guide the treatment of anemic patients; however, their interpretation may be complicated by the etiology of the anemia. We compared anemia-related laboratory values obtained from 261 patients (174 female) screened prior to participation in a clinical trial for cancer and chemotherapy related anemia (ACD), with those from a group of 50 otherwise-healthy women referred for treatment of anemia related to heavy menses (IDA). Pairwise correlations were explored graphically and analyzed using Pearson's correlation coefficients. Highly skewed data were log transformed. Relationships between Hb and laboratory values associated with anemia were explored using multiple linear regression models; the most parsimonious model was arrived at by stepwise regression. For the ACD group, laboratory values tested in the regression analyses included: ferritin, transferrin saturation (TSAT), reticulocyte Hb content, folate, vitamin B12, transferrin, iron, and albumin. For the IDA group, regression analyses included: ferritin, iron binding capacity (TIBC), iron, albumin, BUN, Creatinine, WBC, C-reactive protein, and endogenous EPO. Complete set of lab values was not available for all patients. In the IDA group, a strong correlation was identified between markers of iron status, serum ferritin and TSAT, but this association was much weaker among the ACD group. In the ACD group, negative correlations were identified between ferritin and TIBC, and between ferritin and albumin, along with a moderately strong positive correlation between albumin and TIBC. These relationships were different in the IDA group. Albumin tended to increase with increasing ferritin, while TIBC tended to decrease. Albumin and TIBC were unrelated.Lab value, mean, 95% CIACD groupIDA groupHgb g/dL10.1, 10.0–10.38.6, 8.01–9.10ferritin ng/mL455, 396–51310, 6.1–13.0TSAT%21.3, 19.7–23.012.8, 0.01–25.7TIBC mg/dL275, 267–282422,375–469iron mcg/dL61, 57–6649, 2.5–95.7albumin g/dL3.6, 3.55–3.654.0, 3.86–4.11Correlationsferritin vs TSATr=0.208, p=.001r=0.793, p<.0001ferritin vs albuminr=−0.354, p<.0001r=0.209, p=.144ferritin vs TIBCr=−0.610, p<.0001r=−0.269, p=.059albumin vs TIBCr=0.578, p<.0001r=−0.037, p=.800Among the IDA group, both serum iron (coefficient=0.0129, 95% CI=0.00431–0.0214; p=0.008), and EPO (coefficient = −0.002, 95% CI=−0.001 to−0.003; p=0.008) were significant independent predictors of Hgb, such that lower serum iron and higher endogenous EPO levels were associated with lower Hgb. However, among the ACD group, the only consistent and clinically significant independent predictor of Hgb was serum albumin (coefficient = 1.22, 95% CI = 0.97–1.48; p<0.0001), such that lower serum albumin was associated with lower Hgb. Serum ferritin is an acute-phase reactant that increases during inflammatory states, whereas both serum transferrin and serum albumin are negative acute-phase reactants that decrease during inflammatory states. Elevated serum ferritin and decreased transferrin/TIBC may mask an underlying state of iron deficiency in inflamed patients. While traditional biochemical markers ferritin and TSAT can assist in diagnosis of iron deficiency in otherwise-healthy anemic individuals, they are of limited value in the detection of iron deficiency associated with chronic disease.

Anemia in Cystic Fibrosis (CF): Prevalence, Mechanisms and Correlation with Pulmonary Function.

CF is a chronic disease associated with inflammation and an unknown prevalence of anemia. In other settings anemia is associated with increased morbidity and mortality, and recognition and correction of anemia in CF patients might lead to better outcomes. We hypothesized that chronic inflammation (ACI), iron deficiency (IDA) and malabsorption may be important mechanisms contributing to the anemia in CF patients.METHODS: Clinical charts and portCF.org visit logs of 218 patients of all ages (1 m to 61 yrs) with CF were reviewed for as many years as charts permitted (range 1–7 yrs). The following data were extracted: CBC, iron studies, pulmonary function tests (PFTs), vitamins A, D, and E levels, creatinine, pertinent medical history, and current medications. Anemia was defined by age- and gender-specific WHO criteria. Patients were considered anemic if low Hb was present on two separate occasions at least two months apart, or average annual Hb met WHO criteria. PFTs in 176 patients (all >6 yrs) included forced expiratory volume (FEV1) and forced vital capacity (FVC) as percent predicted of normal and were considered a reflection of patient performance. The most representative annual PFT from at least 4 annual tests was chosen for analysis since acute infection adversely influences daily performance. Semiannual vitamin levels of 47 adults were correlated with corresponding Hb values.RESULTS: 61 of 218 patients, ages 1 m to 61 yrs, were anemic (prevalence 28%). The percent of anemia in different age groups varied. Children <11yrs had a prevalence of anemia of 18.5% while adolescents had a prevalence of only 4%. Of 111 adults >18 yrs, 48 were anemic (43%) with a progressive age-related increase in the prevalence of anemia reaching 58% in patients >40 yrs. Complete iron studies were available in 16/48 patients. 7 were identified as IDA, 4 as ACI, and 3 as combined; 2 others had renal failure. In 32 patients, iron studies were incomplete, but renal failure, hemoptysis, hematochezia and solid organ transplants were contributing factors in half. PFTs obtained in 176 patients >7 yrs were compared in anemic and non-anemic patients. Mean FEV1 and FVC at all ages were statistically significantly poorer in the anemic patients (p <0.005). There was no correlation between vitamin levels and Hb. Complete iron studies were also available in 9 non-anemic patients with impaired lung function. 8/9 patients had ferritins <35 ng/ml. Transferrin saturation was <18% in 7 and 21% and 23% in the remaining 2, suggesting relative iron deficiency.CONCLUSIONS: The prevalence of anemia in CF patients is high and increases with age. In patients for whom iron studies were available, IDA was the prominent underlying mechanism, followed by ACI or a combination of both. There was no correlation between fat soluble vitamin levels and Hb, indicating malabsorption is not a major contributor to the anemia. There was a strikingly significant association between anemia and poor pulmonary function in all age groups. In addition, a group of non-anemic patients with poor lung function had relative iron deficiency. Our results indicate that iron deficiency in anemic CF patients, as well as relative iron deficiency in non-anemic CF patients might be underrecognized and undertreated. Since anemia is associated with poor pulmonary function, correction of anemia should be attempted. Identification of relative iron-deficient states in non- or borderline anemic CF patients with poor lung function could be important since iron supplementation might allow Hb levels to increase as an appropriate response to hypoxia.

The Use of Iron Sucrose Complex for Anemia in Pregnancy and the Postpartum Period

Iron-deficiency anemia resulting in reduced blood reserves is one the most common problems in pregnancy. It is estimated that 20% to 50% of the world population is suffering from iron deficiency and iron-deficient states, pregnancy being one of the most important “risk factors” for iron deficiency and iron-deficiency anemia. The traditional treatments, ie, oral iron therapy and blood transfusion, involve significant drawbacks. High doses of oral iron frequently cause side effects, and noncompliance is common. Therefore, intravenous iron, alone or in association with recombinant human erythropoietin (rHuEPO) therapy, has been considered as an alternative in the management of iron deficiency in this setting. There is increasing evidence that iron sucrose is safe for the mother and the fetus using the recommended dosages and therapy regimens. Iron sucrose is effective in pregnant and postpartum patients who do not respond to oral iron, who are noncompliant to oral iron, or who are treated with rHuEPO. In both cases, according to the present data, the expected hemoglobin increase and time for therapy are predictable in responding patients. Whether it is reasonable to wait for a response to oral iron in moderate to severe anemia is therefore questionable. Indications for the use of iron sucrose complex are: preexisting (moderate–severe) anemia; no effect of oral iron; side effects of oral iron; refusal of blood transfusion (eg, Jehovah’s Witness patients); limited time until delivery; coexisting risks (eg, bowel disease, renal disease); pre- and postoperative period and postpartum anemia. Future fields of research are the evaluation of patient satisfaction and quality of life, impact on costs and hospital stay, impact on blood transfusion frequency and mortality rate, and finally impact on other factors such as breast feeding behavior and neonatal outcome such as birth weight, prematurity and neonatal iron stores.

Restless legs syndrome

The signs and symptoms, epidemiology, etiology, pathophysiology, diagnosis, pharmacologic and nonpharmacologic treatments, and options and guidelines for the treatment of restless legs syndrome (RLS) are reviewed. RLS was first described in the 17th century and further characterized in 1945. RLS is a common disorder, occurring in about 10% of the population. Patients with RLS often describe the urge to move, uncomfortable sensations, and pain, which begin or worsen during rest or inactivity such as lying or sitting. Symptoms of RLS make sleeping difficult for many patients, and significant daytime difficulties result from the condition. RLS can either be primary or arise from secondary causes that lead to iron deficiency. There is a familial component in primary RLS, but its underlying mechanisms remain unknown. Of individuals with conditions associated with iron-deficiency states, including pregnancy, renal failure, and anemia, 25-30% may develop RLS. The goals of RLS treatment include improving its symptoms and the patient's quality of life. There are limited data on the treatment of RLS. Pharmacologic therapies include iron replacement, dopaminergic agents (e.g., levodopa), dopamine agonists, anticonvulsants, opioids, and benzodiazepines. There have been no systematic trials of nonpharmacologic therapies for RLS, but good sleep hygiene and avoidance of alcohol, caffeine, and nicotine may improve symptoms. RLS is a common disorder thought to involve abnormal iron metabolism and dopaminergic systems. Nonpharmacologic therapy should be suggested for all patients with RLS, but pharmacologic therapy may be required, and evidence is strongest for levodopa and dopamine agonists.

The Diagnostic Plot: A Concept for Identifying Different States of Iron Deficiency and Monitoring the Response to Epoetin Therapy

Iron balance is regulated by the rate of erythropoiesis and the size of the iron stores. Anemia that accompanies infection, inflammation, and cancer (anemia of chronic disease) features normal or increased iron stores, although patients may have functional iron deficiency, namely, an imbalance between iron requirements of the erythroid marrow and the actual supply. The proportion of hypochromic red cells and the hemoglobin content of reticulocytes are direct indicators of functional iron deficiency. Biochemical markers, especially the soluble transferrin receptor/log ferritin ratio (ferritin index), are useful indicators of the iron supply to erythropoiesis. The relationship between functional iron deficiency (reticulocyte hemoglobin content) and iron supply to erythropoiesis (ferritin index) can be described in a diagnostic plot. In normoproliferative and hypoproliferative erythropoiesis, the plot allows the differentiation of classic iron deficiency from anemia of chronic disease and the combined state of functional iron deficiency with anemia of chronic disease. The therapeutic implications of the plot are to differentiate patients into those who should be administered iron supplements, epoetin, or a combination of epoetin and iron. In patients receiving epoetin therapy, the plot is an important tool for monitoring erythropoietic activity, functional iron deficiency, and adequate iron stores for new red cell production. Enhanced erythropoiesis is reflected quantitatively by the ferritin index vector. A transgression of the 1.5 (3.2) cut-off value for the ferritin index indicates that extra doses of iron need to be administered to increase the body's iron stores. A lack of increase or a reticulocyte hemoglobin content below 28 picograms indicates functional iron deficiency. The diagnostic plot is a model for differentiating iron-deficient states and predicting those patients who will respond to epoetin therapy.

The many faces of celiac disease: Clinical presentation of celiac disease in the adult population

The major modes of presentation of patients with celiac disease are the classic diarrhea-predominant form and silent celiac disease. Those with silent celiac disease lack diarrhea, although they may present with manifestations of celiac disease that include an irritable bowel syndrome, anemia, osteoporosis, neurologic diseases, or malignancy. A significant proportion of patients are diagnosed through screening at-risk groups including relatives of patients and insulin-dependant diabetics. Nondiarrheal presentations now are seen more commonly than those with diarrhea. Patients with celiac disease have a greater burden of disease than the general population because of autoimmune diseases and malignancies. There is a need for screening studies of patients with conditions associated with celiac disease to determine whether the large numbers of people with undiagnosed celiac disease currently are seeking health care.

Identification of differentially expressed genes in response to dietary iron deprivation in rat duodenum

We sought to identify novel genes involved in intestinal iron absorption by inducing iron deficiency in rats during postnatal development from the suckling period through adulthood. We then performed comparative gene chip analyses (RAE230A and RAE230B chips; Affymetrix) with cRNA derived from duodenal mucosa. Real-time PCR was used to confirm changes in gene expression. Genes encoding the apical iron transport-related proteins [divalent metal transporter 1 (DMT1) and duodenal cytochrome b] were strongly induced at all ages studied, whereas increases in mRNA encoding the basolateral proteins iron-regulated gene 1 and hephaestin were observed only by real-time PCR. In addition, transferrin receptor 1 and heme oxygenase 1 were induced. We also identified induction of novel genes not previously associated with intestinal iron transport. The Menkes copper ATPase (ATP7a) and metallothionein were strongly induced at all ages studied, suggesting increased copper absorption by enterocytes during iron deficiency. We also found significantly increased liver copper levels in 7- to 12-wk-old iron-deficient rats. Also upregulated at most ages examined were the sodium-dependent vitamin C transporter, tripartite motif protein 27, aquaporin 4, lipocalin-interacting membrane receptor, and the breast cancer-resistance protein (ABCG2). Some genes also showed decreased expression with iron deprivation, including several membrane transporters, metabolic enzymes, and genes involved in the oxidative stress response. We speculate that dietary iron deprivation leads to increased intestinal copper absorption via DMT1 on the brush-border membrane and the Menkes copper ATPase on the basolateral membrane. These findings may thus explain copper loading in the iron-deficient state. We also demonstrate that many other novel genes may be differentially regulated in the setting of iron deprivation.

Usefulness of soluble transferrin receptor and ferritin in iron deficiency and chronic disease

Soluble transferrin receptor (sTfR) is a biochemical parameter used for the detection of iron deficiency in situations where ferritin has limited diagnostic value owing to the present chronic disease. The sTfR concentration was determined in 118 patients divided according to their inflammatory status and underlying disease into groups of patients with iron‐deficiency anemia (IDA), anemia of chronic disease (ACD) and patients with a coexisting state of iron deficiency and anemia of chronic disease (ID+ACD). All patients with iron deficiency had elevated sTfR levels, but ferritin concentrations were normal or increased in patients with inflammatory characteristics. Diagnostic efficiencies of sTfR, sTfR/log ferritin index (sTfR/F) and ferritin were evaluated by receiver operating characteristic curve (ROC) analysis. According to the results obtained, the best diagnostic efficiency for differential diagnosis of anemic patients with iron deficiency compared to the control group had a sTfR concentration (0.884) that was significantly higher than ferritin (0.638), but not higher than the calculated ratio sTfR/F (0.820). The cut‐off value of the sTfR/F index differentiating the best control group from the IDA and ID+ACD groups was 1.30, and for differentiation of ACD from IDA and ID+ACD, the value was 0.90. Soluble transferrin receptor is an additional parameter to ferritin for the diagnosis of IDA and differential diagnosis of ID+ACD, but calculation of the sTfR/F index did not improve the diagnostic value of determining sTfR alone.

On the Resurgence of the Hematologist as Consultant to Primary Care Practitioners.

The widespread use of “routine” automated blood testing in primary care practice appears to have increased the demand for consultative services by hematologists. To explore this hypothesis, we tracked consecutive first-time referrals to our university hospital hematology clinic retrospectively between July 2002 and June 2003 and prospectively from July 2003 to May 2004. Findings were similar in both time intervals and thus are combined for reporting. Of 557 consultative referrals, 326 patients (58.5 %) were referred for abnormalities of the peripheral blood counts, 209 (64%) of which were detected as incidental findings in asymptomatic patients. 144 (26%) of all referrals were for anemia and 79 (55%) of those proved to have primary medical conditions including active alcoholism, medication effects, chronic renal failure, iron deficiency, chronic inflammatory diseases or advanced liver disease. The rest had hematological disorders including, myelodysplastic syndromes, hemoglobinopathies, hemolytic anemias, and others. 66 (12%) of all referrals were for abnormalities of the white blood cell count and only 24 (36%) turned out to have a primary hematological disorder (e.g. CLL, CML or benign chronic leukopenia). The other 42 (64%) had primary medical disorders including leukocytosis of smoking or pregnancy, allergies, anti-convulsant-related leukopenia, etc. 50 patients were referred for thrombocytopenia or thrombocytosis, of which 29 (58%) had primary medical disorders including iron deficiency or inflammatory states, gestational thrombocytopenia, known hypersplenism, medication-related thrombocytopenia, or alcoholism. Similarly 20 of the 40 patients referred for bi- or pancytopenias had primary hematological disorders and 20 had medical disorders that included hypersplenism, drugs, or mild disorders that resolved by the time of referral. The remaining 231 patients (41.5%) included 69 who were referred for evaluation of, and counseling for, hypercoagulable disorders, 39 referred for presumed bleeding disorders (4 had senile purpura; 9 had storage pool disorders), 9 with hereditary hemochromatosis, 51 with hematological malignancies, 12 with unexplained lymphadenopathy (8 with infectious mononucleosis or other reactive lymphadenopathy, 1 with enlarged tonsils, 1 CLL, 1 T-cell lymphoma, 1 Kimura's disease) and 9 patients with polyclonal hyperglobulinemia. Overall, only 45 % of the patients referred for consultation turned out to have a primary hematological disorder. The rest had conditions that are traditionally considered to be in the realm of internal medicine or primary care. Most consults were initiated based on incidental abnormalities of the CBC that were not, or could not be, worked up by the referring physician. Thus primary care practitioners are relying on hematologists to explain routine findings in often-asymptomatic patients with fortuitous abnormalities of the peripheral blood counts. Medical surveillance of asymptomatic patients is likely to result in progressively early detection of subtle changes in the CBC that internists and others will rely on hematologists to explain. Thus the hematologist's role as consultant continues to expand.

Strategien zur Bluteinsparung in der Chirurgie: Der Stellenwert von Erythropoetin und der parenteralen Eisensubstitution

Recombinant human erythropoietin (rHuEPO) and intravenous (i.v.) iron administration may be useful tools to save blood in surgery. In the perioperative period, rHuEPO should be used in slightly anemic patients for whom an autologous predonation program is not recommended (or feasible). In such cases, i.v. iron is only given if there is a functional or real iron deficiency state. In the post-operative period, i.v. iron is administered in association with rHuEPO in an attempt to rapidly correct severe post-operative anemia. The same regimen is used for patients undergoing surgery for inflammatory bowel disease and rheumatoid arthritis. Finally, other particular categories of patients, such as those with reduced body weight (< 50 kg), candidates for surgery with increased blood needs (> 5 units), or those with a too-short period of time before surgery, also benefit from the administration of these two drugs.

Potential utility of Ret-Y in the diagnosis of iron-restricted erythropoiesis.

Diagnosis of iron deficiency (ID) or functional iron deficiency (FID) is particularly challenging in patients with acute or chronic inflammatory conditions because most biochemical markers for iron metabolism are affected by the acute-phase response (APR) (1). The hemoglobin content of reticulocytes (CHr) is an early and sensitive indicator of FID (2). Recently, we presented a novel approach to provide insights into the diagnosis of FID in APR by use of the CHr (3). ID and FID were defined as a CHr <28 pg based on the distribution of CHr and biochemical markers of iron status in healthy controls. When a CHr <28 pg was used for identification of ID and FID in anemic patients, the values of ferritin, soluble transferrin receptor (sTfR), and the sTfR-F index (sTfR/log ferritin) (4) performed significantly better in patients without APR [based on a C-reactive protein (CRP) cutoff of 5 mg/L]. In ID combined with inflammation, the cutoff value for the sTfR-F index was 0.8, and in simple ID, it was 1.5. A diagnostic plot was developed that combined CHr and sTfR-F index, which allowed identification of four major categories of ID: ( a ) iron repletion, normal erythropoiesis; ( b ) patients with reduced iron supply, but not yet in an iron-deficient erythropoietic state; ( c ) depletion of storage and functional iron with decreased hemoglobinization of erythrocytes, classic ID; and ( d ) FID in an iron-replete state, with decreased hemoglobinization of erythrocytes. The plot provided a useful approach to the diagnosis of iron-deficient states. To date, the measurement of reticulocyte hemoglobin has been restricted to the analyzers of a single manufacturer. Now a second manufacturer has produced what would appear to …

Reply to the letter to the editor submitted by Burkhardt et al.

In response to the letter of Burkhardt et al. (1), we concur with the authors of the letter that multi-angle light scatter can be used to establish the size and hemoglobin concentration of red blood cells (RBCs) that are isovolumetrically sphered in an appropriately formulated isotonic reagent (normal discoidal RBCs are sphered in such reagent). It is also clearly evident that knowledge of the cell size and hemoglobin content of RBCs is valuable in pointing towards RBC abnormalities. The key novelties illustrated by our work is the observations that in a carefully selected three dimensional (3D) space, the scatter signals from the 3 angular intervals of RBCs which were not sphered in the reagent did not fall close to the pre-calibrated grid of the 3D surface conserved to sphered RBCs. The abbreviation which was specifically used to refer to abnormally-shaped RBCs was AbnRBC as defined in the article Abstract on page 43. The term “AbnRBC” was not intended to refer to RBC abnormalities for cell size or hemoglobin concentration, as pointed out again on page 51 under Table 5 (note a) of our article. Thus, it was with specific reference to RBCs which were not sphered in both RBC reagents that we made our observations. In their letter, Burkhardt et al. (1) also suggest that our paper implies a discrete separation of sphered and non-sphered RBCs by the 3D method. This was not our intention and on review of our manuscript, it is difficult to understand why the authors of the letter feel that this is implied. In a situation analogous to cell volume and cell hemoglobin concentration, abnormalities in cellular shape are commonly a continuum of spectrum of magnitude rather than being compartmentalized populations. We have on hand, numerous instances in which samples containing AbnRBCs show cytometric events falling more distant from the calibrated 3D surface than is the case in normal bloods. In Figure 3 of our article, we show an example of a normal sample and a sample containing AbnRBCs. As clearly shown in Fig 3d, it was never suggested that AbnRBCs form a discrete cluster. For the proposed method to be of value, boundaries of abnormality have to be established which give reference ranges for normal RBCs. Six samples in Table 5 of our article contained AbnRBCs as shown and the results analyzed by the closest point finding software of the 3D method was compared to the blood smear results. Fairly good correlation was obtained between the two methods. Concerning schistocytes, at the time of writing the article, we were unaware of any 510(k) cleared reportable parameters pertaining to schistocyte counting derived from any of the Bayer systems. If the situation has been changed since and Bayer hematology instruments now can count and report schistocytes, thank you for informing us. On the last comment in the Letter, the authors refer to the CHr parameter as a “Gold Standard” for iron-deficiency state. To assert that the CHr is the gold standard, implying it being a reference method, is not only not supported in the literature, but is not indicated as such by any publication we can find by a recognized international laboratory standards group, such as ICSH or NCCLS. Therefore, we said that we planned to investigate this area further because the diagnostic threshold for iron deficiency seems to vary with the patient population (2, 3) and may not be reliable in individuals with elevated red cell MCV values (4) (Blood). The finding of alterations in the CHr in healthy individuals following extreme exercise also raises questions as to the specificity of the measurement (5). Perhaps, the claim of red cell parameters serving as a gold standard will require the combination of several measurements, such as both the CHr and the reticulocyte IRF (RNA content) (6). The term, anemia of chronic diseases, was used in our article to describe a broad spectrum of anemias associated with chronic disease state.

P0726 IMPAIRED INTESTINAL IRON ABSORPTION IN CROHN???S DISEASE CORRELATES WITH DISEASE ACTIVITY AND INFLAMMATORY CYTOKINES

Introduction: The anemia of chronic inflammation in Crohn’s disease (CD) is multifactorial, and may be secondary to defective intestinal iron absorption, impaired iron delivery to erythroid precursors, impaired iron release from macrophages, and impaired erythropoietin production. The oral iron absorption test is a simple, minimally invasive method to establish whether oral iron can be absorbed by patients with iron deficiency and inflammatory states. In this study, we have evaluated this test in patients with CD, and correlated iron absorption with disease activity and with markers of systemic inflammation. Methods: Seventeen patients with CD (F=6,M=11) were recruited for this study. The patients were on a combination of medications, including: 5-ASA (N=7), corticosteroids (N= 7), and 6-mercaptopurine/azathioprine (N= 8) and infliximab (N=4). Of the 17 patients, 5 had active CD, as defined by a Pediatric Crohn’s Disease Activity Index (PCDAI) of >30 points. Twelve patients had inactive/mild CD (PCDAI<=30). Patients were admitted to the Children’s Hospital General Clinical Research Center after an overnight fast, and indwelling IV access was established. Baseline bloodwork obtained prior to the study included complete blood count, erythrocyte sedimentation rate, C-reactive protein, serum iron, TIBC, Ferritin, interleukins 1 and 6, and tumor necrosis factor. Oral Ferrous sulfate (1mg/ kg of elemental iron) was then administered. Iron levels were drawn at 1, 2, 3, and 4 hours after the administration of oral iron. The area under the curve (AUC) for iron absorption was calculated as the sum of the areas under the trapezoids formed between time points of serum iron levels. Results: Patients with active CD had markedly impaired iron absorption (mean AUC 154, compared to mean AUC 501 in inactive/mild). Iron absorption (AUC) correlated inversely with PCDAI and IL-6 (Spearman rho = −0.52, p= 0.03), (Table).Table 1: Iron Challenge Test and Inflammatory Markers in Active and Inactive CDConclusion: The oral iron challenge test is a simple method of determining an individual’s ability to absorb supplemental iron. Impaired intestinal iron absorption in CD is a function of disease activity.

Iron overload in adult Hfe-deficient mice independent of changes in the steady-state expression of the duodenal iron transporters DMT1 and Ireg1/ferroportin.

Patients suffering from hereditary hemochromatosis (HH) show progressive iron overload as a consequence of increased duodenal iron absorption. It has been hypothesized that mutations in the HH gene HFE cause misprogramming of the duodenal enterocytes towards a paradoxical iron-deficient state, resulting in increased iron transporter expression. Previous reports concerning gene expression levels of the duodenal iron transporters DMT1 and IREG1 in HH patients and animal models are controversial, however, and in many cases only mRNA expression levels were investigated. To analyze the duodenal expression of DMT1, Ireg1, Dcytb, and hephaestin and the association with iron overload in adult Hfe(-/-) mice, an Hfe(-/-) mouse line was generated. Duodenal DMT1 and Ireg1 protein levels, duodenal DMT1, Ireg1, Dcytb, hephaestin, and TfR1 mRNA levels, and hepatic hepcidin mRNA levels were quantified and the correlation to liver iron contents was calculated. We report that duodenal DMT1 and Ireg1 mRNA levels and DMT1 and Ireg1 protein levels remained unaffected by the Hfe deletion. Furthermore, duodenal hephaestin and TfR1 mRNA expression and hepatic hepcidin mRNA expression remained unaltered, while the duodenal mRNA expression of the brush border ferric reductase Dcytb was significantly increased in Hfe(-/-) mice. We found no correlation between the expression level of any of the analyzed transcripts and the liver iron content. In conclusion, the lack of correlation between DMT1 and Ireg1 protein expression and the liver iron content suggests that elevated duodenal iron transporter expression is not required for high liver iron overload. Hfe(-/-) mice do not necessarily display features of iron deficiency in the duodenum, indicated by an increase in mRNA and protein levels of DMT1 and Ireg1. Rather, the duodenal ferric reductase Dcytb may act as a possible mediator of iron overload in Hfe deficiency.

Anaemia and inflammation: what are the implications for the nephrologist?

End-stage renal disease (ESRD) is characterized by a high mortality rate, which is mainly caused by cardiovascular disease. In patients with ESRD, high levels of pro-inflammatory cytokines and increased oxidative stress are common features and may contribute to the development of malnutrition, anaemia, resistance to recombinant human erythropoietin (epoetin) and atherosclerosis. The onset of inflammation is multi-factorial and is a predictor of poor outcome in ESRD. Although the inflammation may reflect the underlying cardiovascular disease, the acute-phase response may also contribute to both oxidative stress and progressive vascular injury. The acute-phase response in these patients may be influenced by a number of factors, and possibly the dialysis procedure itself. Inflammation and the acute-phase response interact with the haematopoietic system at several levels, resulting in reduced erythropoiesis, accelerated destruction of erythrocytes and blunting of the reactive increase in erythropoietin in response to reduced haemoglobin levels. In patients with ESRD, epoetin resistance has been linked with inflammation, which is often associated with a state of functional iron deficiency. Patients with ESRD are thought to have a reduced capacity in their control of oxidative stress and there is evidence that suggests that a relationship may exist between inflammation, oxidative stress and the treatment of anaemia with epoetin. Controlled trials are needed before evidence-based recommendations for the management of inflammation-induced anaemia and resistance to epoetin can be defined.

Iron deficiency and erythropoiesis: new diagnostic approaches.

Iron deficiency anemia is one of the most common diseases worldwide. In the majority of cases, the presence of hypochromic microcytic anemia and biochemical evidence for depletion of body iron stores makes the diagnosis relatively straightforward. However, in several clinical conditions, classic biochemical indices such as serum iron, transferrin saturation, and ferritin may not be informative or may not change rapidly enough to reflect transient iron-deficient states (functional iron deficiency), such as the ones that develop during recombinant human erythropoietin (r-HuEPO) therapy. The identification and treatment of iron deficiency in settings such as r-HuEPO therapy, anemia of chronic disease, and iron deficiency of early childhood may be improved by the use of red cell and reticulocyte cellular indices, which reflect in almost real time the development of iron deficiency and the response to iron therapy. In the anemia of chronic disease, measurements of plasma cytokines and iron metabolism regulators such as hepcidin (when available) may be helpful in the characterization of the pathophysiologic basis of this condition. The ratio of serum transferrin receptor (sTfR) to serum ferritin (R/F ratio) has been shown to have excellent performance in estimating body iron stores, but it cannot be used widely because of the lack of standardization for sTfR assays. The combination of hematologic markers such as reticulocyte hemoglobin content, which decreases with iron deficiency, and R/F ratio may allow for a more precise classification of anemias.