Advanced glycosylation end products as metabolic predictors of systemic pro-inflammatory and prooxidant status in patients with end-stage renal disease

Controlling systemic proinflammatory and prooxidant effectors is essential for mitigating cardiovascular risk and mortality in patients with end-stage renal disease (ESRD). However, monitoring these processes is still challenging due to the high uncertainty about their determinants and predictors. Thus, we investigated the relationship between advanced glycosylation end products (AGE), proinflammatory and prooxidant effectors in ESRD patients undergoing hemodialysis (HD). In addition to nutritional profile and dialysis efficiency, AGE, cytokines, chemokines, C-reactive protein (CRP), total (TAC) and non-protein (npAC) antioxidant capacity, lipid and protein oxidation were analyzed in blood samples from 43 HD patients. AGE, CRP, cytokines, chemokines, protein carbonyl (PCn), and malondialdehyde (MDA) were upregulated, while TAC and npAC were down-regulated in HD patients compared to heath subjects. Dialysis efficiency, TAC and npAC were reduced, while leucocytes counting, pre- and post-HD urea, TNF, IL-6, IL-10, CCL-2, MIP-1β, PCn, and MDA were increased in patients with higher AGE accumulation compared to those with lower AGE levels. Serum levels of CRP, protein carbonyl, malondialdehyde, and all cytokines and chemokines analyzed were correlated with AGE circulating levels for patients with higher AGE accumulation. AGE was inversely correlated with IL-10, TAC and npAC in patients with higher AGE accumulation. AGE exhibited predictive value (determination coefficient) to explain CRP, cytokines, chemokines, PCN, MDA, TAC and npAC variability in patients with higher AGE levels. Taken together, our findings provide evidence that AGE accumulation is associated with important proinflammatory and prooxidant effectors in patients with ESRD undergoing hemodialysis. Thus, AGE monitoring may be relevant to predict systemic inflammatory stress and the balance between oxidant and antioxidant status in these patients.

Associations of iron status with breast cancer risk factors in adult women: Findings from National Health and Nutrition Examination Survey 2017-2018

OBJECTIVE

This study examined the association between iron status and a set of breast cancer risk factors among U.S. adult women aged 20-80 years.

METHODS

Data from National Health and Nutrition Examination Survey (2017-2018) were used to examine the relation between serum ferritin, serum iron and transferrin saturation with a set of breast cancer risk factors [body mass index (BMI), waist circumference, glycosylated hemoglobin (HbA1c), fasting plasma glucose, insulin and HOMA-IR]. The multivariable linear regressions were used controlling for age, race/ethnicity, menopause status, education level, smoking status, alcohol consumption, physical activity, high-sensitivity C-reactive protein (hsCRP) and total energy intake.

RESULTS

HbA1c, BMI and waist circumference data were available for 1902 women with a fasting sample (n = 913) for fasting plasma glucose, insulin and HOMA-IR. Transferrin saturation had significant, inverse associations with BMI, waist circumference and HbA1c. The size of difference observed were that participants in the fourth quartile of transferrin saturation had a 4.50 kg/m² smaller BMI, a 9.36 cm smaller waist circumference and a 0.1 % lower HbA1c level than participants in the first quartile. Similarly, serum iron concentrations were inversely associated with BMI and waist circumference. In addition, serum iron had significant, inverse associations with insulin and HOMA-IR. Sensitivity analyses among men gave similar results. For serum ferritin, there was a trend towards a positive association between waist circumference, HbA1c and fasting plasma glucose with serum ferritin. However, the associations did not reach statistical significance among women.

CONCLUSIONS

Iron status may impact breast cancer risk via effects on adiposity or glucose metabolism. The findings should be confirmed with further prospective data.

Cytokines and chemokines systemic levels are related to dialysis adequacy and creatinine clearance in patients with end-stage renal disease undergoing hemodialysis

Although the clearance of low-molecular weight toxins is modulated by dialysis dose, the relationship between dialysis adequacy and middle systemic inflammatory mediators is often overlooked. Thus, the relationship between dialysis adequacy, pro- and anti-inflammatory cytokines and chemokines in hemodialysis (HD) patients was investigated. Forty-eight HD patients (19 women and 25 men) were investigated. Age, body mass index, time in HD, nutritional status, Kt/V and blood biochemical parameters was similar in patients of both sexes (P > 0.05). Thus, patients were stratified by dialysis adequacy measured by Kt/V method (adequate Kt/V ≥ 1.2). Post-HD urea, creatinine, cytokines (IFN-γ, IL-4 and IL-10) and chemokines (CCL-2, CCL-5, CXCL-8 and CXCL-10) were higher in patients with Kt/V < 1.2 (P < 0.05). Kt/V exhibited significant correlation with CXCL-10/IP-10 serum levels. Positive correlation between creatinine with IFN-γ, CCL-2/MCP-1, and CXCL-10/IP-10, and negative correlation with IL-10 was identified in patients with Kt/V < 1.2 (P < 0.05). In patients with Kt/V ≥ 1.2, only IL-10 was positively and CXCL-10/IP-10 negatively correlated with creatinine levels (P < 0.05). Kt/V and creatinine levels exhibited variable predictive value (Kt/V = 27% to 37%, creatinine = 29% to 47%) to explain cytokines and chemokines circulating levels in patients with adequate and inadequate dialysis dose. Taken together, our findings provide evidence that in addition to modulating uremic toxins levels, such as urea and creatinine, dialysis dose is associated with circulating levels of inflammatory mediators. Thus, low Kt/V results and creatinine accumulation are potential indicators of the systemic inflammatory stress determined by up-regulation of proinflammatory cytokines and chemokines, and downregulation of anti-inflammatory cytokines.

Iron deficiency contributes to resistance to endogenous erythropoietin in anaemic heart failure patients

AIMS

Abnormal endogenous erythropoietin (EPO) constitutes an important cause of anaemia in chronic diseases. We analysed the relationships between iron deficiency (ID) and the adequacy of endogenous EPO in anaemic heart failure (HF) patients, and the impact of abnormal EPO on 12-month mortality.

METHODS AND RESULTS

We investigated 435 anaemic HF patients (age: 74 ± 10 years; males: 60%; New York Heart Association class I or II: 39%; left ventricular ejection fraction: 43 ± 17%). Patients with EPO higher than expected for a given haemoglobin were considered EPO-resistant whereas those with EPO lower than expected - EPO-deficient. ID was defined as serum ferritin <100 µg/L or 100-299 µg/L with transferrin saturation <20%. EPO-resistant patients (22%) had more advanced HF whereas those with EPO deficiency (57%) were more frequently females and had worse renal function. Lower serum ferritin (indicating depleted body iron stores) was related to higher EPO observed/predicted ratio when adjusted for significant clinical confounders, including C-reactive protein. One year all-cause mortality was 28% in patients with EPO resistance compared to 17% in patients with EPO deficiency and 10% in patients with adequate EPO (log-rank test for the comparison EPO resistance vs. adequate EPO: P = 0.02). When adjusted for other prognosticators, there was still a trend towards increased 12-month mortality in patients with higher EPO level.

CONCLUSION

Anaemic HF patients with endogenous EPO deficiency vs. resistance have different clinical and laboratory characteristics. In such patients, ID contributes to EPO resistance independently of inflammation.

Iron deficiency in worsening heart failure is associated with reduced estimated protein intake, fluid retention, inflammation, and antiplatelet use

Aims

Iron deficiency (ID) is common in heart failure (HF) patients and negatively impacts symptoms and prognosis. The aetiology of ID in HF is largely unknown. We studied determinants and the biomarker profile of ID in a large international HF cohort.

Methods and results

We studied 2357 worsening HF patients from the BIOSTAT-CHF cohort. ID was defined as transferrin saturation <20%. Univariable and multivariable logistic regression models were constructed to identify determinants for ID. We measured 92 cardiovascular markers (Olink Cardiovascular III) to establish a biomarker profile of ID. The primary endpoint was the composite of all-cause mortality and first HF rehospitalization. Mean age (±standard deviation) of all patients was 69 ± 12.0 years, 26.1% were female and median N-terminal pro B-type natriuretic peptide levels (+interquartile range) were 4305 (2360–8329) ng/L. Iron deficiency was present in 1453 patients (61.6%), with highest prevalence in females (71.1% vs. 58.3%; P < 0.001). Independent determinants of ID were female sex, lower estimated protein intake, higher heart rate, presence of peripheral oedema and orthopnoea, chronic kidney disease, lower haemoglobin, higher C-reactive protein levels, lower serum albumin levels, and P2Y₁₂ inhibitor use (all P < 0.05). None of these determinants were sex-specific. The biomarker profile of ID largely consisted of pro-inflammatory markers, including paraoxonase 3 (PON3) and tartrate-resistant acid phosphatase type 5. In multivariable Cox proportional hazard regression analyses, ID was associated to worse outcome, independently of predictors of ID (hazard ratio 1.25, 95% confidence interval 1.06–1.46; P = 0.007).

Conclusion

Our data suggest that the aetiology of ID in worsening HF is complex, multifactorial and seems to consist of a combination of reduced iron uptake (malnutrition, fluid overload), impaired iron storage (inflammation, chronic kidney disease), and iron loss (antiplatelets).

Efficacy of an iron-fortified infant cereal to reduce the risk of iron deficiency anemia in young children in East Cameroon

Complementary foods in Africa are often poor sources of bioavailable iron. We assessed the efficacy of iron-fortified wheat-based infant cereal (IC) to reduce the risk of iron deficiency anemia in children aged 18-59 months in Cameroon. A 6-month double-blind, cluster-randomized controlled trial was conducted in 2017 among anemic (hemoglobin 7-11 g/dl) but otherwise healthy children. In conjunction with usual diet, children received two 50 g servings/day of a standard, micronutrient-fortified IC (providing 3.75 mg iron/serving; n = 106) or the same IC without iron fortification (n = 99). Anthropometric measurements, blood sampling, and systematic deworming were performed in all children at baseline (pre-intervention), 3, and 6 months. Mean hemoglobin, ferritin adjusted for C-reactive protein (CRP), serum iron, transferrin saturation, prevalence of anemia, iron deficiency, and iron deficiency anemia as well as anthropometrics were compared between the groups at baseline, 3, and 6 months. Compared to the control group, children consuming the iron-fortified IC had significantly higher baseline-adjusted mean hemoglobin (10.0 ± 1.8 vs. 9.7 ± 1.4 g/dl, respectively; p = .023), ferritin adjusted for CRP (16.1 ± 8.3 vs. 9.5 ± 7.5 μg/L, p < .001), serum iron (14.5 ± 3.9 vs. 11.2 ± 4.4 μg/dl; p < .001), and transferrin saturation (19.0 ± 17.4 vs. 10.7 ± 12.5%; p ˂ .001) at 6 months. The prevalence of anemia, iron deficiency, and iron deficiency anemia at 6 months decreased by a larger extent in the iron-fortified group versus controls (all p < .01). In addition, at 6 months, children in the iron-fortified group demonstrated higher weight-for-age z-scores (p = .016) compared to the control group. Wheat-based IC fortified with 7.5 mg ferrous fumarate administered daily for 6 months improved iron and nutritional status and decreased the prevalence of iron deficiency anemia in children aged 18-59 months in Salapoumbé, Cameroon.

The effect of serum vitamin B12, folate, ferritin levels and transferrin saturation on stem cell mobilization in allogeneic donors

INTRODUCTION

Peripheric blood derived stem cells are used in 75 % of allogeneic stem cell transplantations. Iron, vitamin B12 and folate involve in hematopoiesis. Therefore serum levels of iron, vitamin B12 and folat may effect stem cell mobilization. We aimed to analyze the effects of iron status, vitamin B12 and folate levels on peripheric blood stem cell mobilization in healthy donors.

METHOD

The mobilization results of 218 allogeneic donors were analyzed retrospectively.

RESULTS

In 64 donors, serum ferritin level was <15 μg / L and transferrin saturation was <20 %. When we compared the donors with iron deficiency to the donors without iron deficiency, the number of collected CD34 + cell was significantly higher in donors without iron deficiency. We did not find any impact of serum vitamin B12 and folate level on CD34+ cells collected.

CONCLUSION

Our study shows that serum ferritin and transferrin saturation have a greater effect on the amount of CD34+ cells collected from donors than serum vitamin B12 and folate levels. Consequently, when compliance tests of allogeneic donors are performed, the evaluation of vitamin B12 and folate levels is not necessary; whereas iron deficiency must be assessed and -if possible- corrected before apheresis is performed.

Definition of Iron Deficiency Based on the Gold Standard of Bone Marrow Iron Staining in Heart Failure Patients

BACKGROUND

The most commonly used definition of iron deficiency (ID; ferritin <100 ng/mL or ferritin 100-300 ng/mL and transferrin saturation [TSAT] <20%) has not been validated in patients with heart failure (HF). We aimed to define and validate the biomarker-based definition of ID in HF, using bone marrow iron staining as the gold standard. Second, we aimed to assess the prognostic value of the optimized definition.

METHODS AND RESULTS

Bone marrow aspiration with iron staining was performed in 42 patients with HF and a reduced left ventricular ejection fraction (≤45%) undergoing median sternotomy for coronary artery bypass grafting. Patients were mostly male (76%) with mild-to-moderate HF and a mean age of 68±10 years. Bone marrow ID was found in 17 (40%) of the HF patients. The most commonly used definition of ID had a sensitivity of 82% and a specificity of 72%. A definition solely based on TSAT ≤19.8% or serum iron ≤13 µmol/L had a sensitivity of 94% and specificity of 84% and 88%, respectively (P<0.05 compared with the former definition). Subsequently, we assessed the incidence of all-cause mortality in 387 consecutive outpatient HF patients (left ventricular ejection fraction ≤45%). In these patients, TSAT ≤19.8% and serum iron ≤13 µmol/L, and not ferritin, were independently associated with mortality.

CONCLUSIONS

A TSAT ≤19.8% or a serum iron ≤13 µmol/L shows the best performance in selecting patients with ID and identifies HF patients at the highest risk of death. Our findings validate the currently used TSAT cutoff of <20% for the identification of ID in HF patients, but question the diagnostic value of ferritin.

Iron deficiency and red cell indices in patients with heart failure

AIMS

To investigate the prevalence of iron deficiency (ID) in heart failure (HF) patients with normal vs. abnormal red cell indices (RCI), the associations between iron parameters and RCI, and prognostic consequences of ID independently of RCI.

METHODS AND RESULTS

We analysed clinical data of 1821 patients with HF [mean age 66 ± 13 years; 71% men; New York Heart Association class I/II/III/IV (11%/39%/44%/6%); left ventricular ejection fraction >45%: 19%]. Iron deficiency (ferritin <100 µg/L or ferritin 100-299 µg/L with transferrin saturation <20%) was common irrespective of the presence of anaemia (haemoglobin <12 g/dL in women and <13 g/dL in men) or low RCI, from 75% in anaemic subjects with low mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), and MCH concentration (MCHC), to 36% in non-anaemic subjects with MCV, MCH, and MCHC above the lower limit of normal. After adjustment for clinical variables, iron parameters remained independently associated with haemoglobin, MCV, MCH, MCHC, mean reticulocyte haemoglobin content (CHR), and red cell distribution width (RDW). In multivariable Cox proportional hazard regression models there was a trend towards higher mortality in patients with vs. without ID when adjusted for relevant HF prognosticators and MCH or MCHC (but not haemoglobin, CHR or RDW).

CONCLUSIONS

Patients with HF should be routinely screened for ID irrespective of the presence of anaemia or abnormal RCI. The detrimental impact of ID on long-term survival in HF is partially independent of RCI.

Quantitative data on the magnitude of the systemic inflammatory response and its relationship with serum measures of iron status

The present study aimed to quantify the magnitude of the systemic inflammatory response, measured by C-reactive protein (CRP) and albumin, and its relationship with common serum biochemical measures of iron status including total iron, transferrin, transferrin saturation, and ferritin. Retrospective interrogation of laboratory computer databases at 4 centers between 2006 and 2011 provided results from patients in which serum CRP and albumin had been measured together with iron studies (iron, transferrin, and transferrin saturation, n = 16,522) and ferritin (n = 7,226). Analyte results were categorized into groups according to CRP and albumin. When those groups with CRP <10 mg/L and albumin >35 g/L, CRP 11-80 mg/L and albumin 25-35 mg/L, and CRP >80 mg/L and albumin <25 g/L were compared, the median serum total iron was 15.0, 7.0, and 3.0 μmol/L, respectively (P < 0.001), an overall reduction of 80%. The median serum transferrin concentration was 2.6, 2.0, and 1.3 μmol/L respectively (P < 0.001), an overall reduction of 50%. The median transferrin saturation was 23%, 13%, and 10% respectively (P < 0.001), an overall reduction of 56%. The median serum ferritin was 77, 173, and 445 μg/L respectively (P < 0.001), an overall increase of 578%. The present study quantifies the impact of the systemic inflammatory response on serum measures of iron status. This association should be taken into account when measures of iron status are requested and interpreted to prevent misdiagnosis.

Higher concentrations of serum iron and transferrin saturation but not serum ferritin are associated with cancer outcomes

BACKGROUND

Although the carcinogenic potential of iron has been shown, evidence from observational studies that have linked serum iron variables and cancer outcomes has been inconsistent.

OBJECTIVE

We investigated whether higher iron concentrations increased risk of cancer outcomes.

DESIGN

A prospective examination of iron biomarkers as independent risk factors for cancer was assessed in 1597 men and 1795 women aged 25-79 y who participated in the 1994/1995 Busselton Health Survey and had relevant data, no history of cancer before the survey, and serum ferritin concentrations ≥20 μg/L. Follow-up for incident cancers and death from cancer was available to 2010. Proportional hazards regression modeling was performed to investigate if iron status predicted cancer incidence and mortality.

RESULTS

After adjustments for age, smoking, drinking, anthropometric and biochemical variables, or menopausal status (breast cancer), higher serum iron concentrations and transferrin saturation were associated with increased risks of incident nonskin cancer [HR for iron: 1.83 (95% CI: 1.21, 2.76; P < 0.01); HR for transferrin saturation: 1.68 (95% CI: 1.18, 2.38; P < 0.01)] including breast cancer [HR for iron: 2.45 (95% CI:1.12, 5.34; P < 0.05); HR for transferrin saturation: 1.90 (95% CI:1.02, 3.56; P < 0.05)] in women. Transferrin saturation was also associated with a greater risk of cancer death (HR: 2.48; 95% CI: 1.28, 4.82; P < 0.01). In men, higher iron concentrations were associated with reduced risks of incident nonskin cancer (HR: 0.65; 95% CI: 0.42, 0.99; P < 0.05) including colorectal cancer (HR: 0.34; 95% CI: 0.12, 0.95; P < 0.05). There was no association between serum iron and colorectal cancer risk in women. Serum ferritin was not associated with cancer risk or cancer death.

CONCLUSIONS

Higher transferrin saturation or serum iron concentrations were associated with increased nonskin cancer risk and increased risk of cancer death. Conversely, in men, higher serum iron concentrations were associated with decreased risk of nonskin cancer. The molecular basis for the observed differences in the association between serum iron and nonskin cancer risk is unclear.

Live high, train low - influence on resting and post-exercise hepcidin levels

The post-exercise hepcidin response during prolonged (>2 weeks) hypoxic exposure is not well understood. We compared plasma hepcidin levels 3 h after exercise [6 × 1000 m at 90% of maximal aerobic running velocity (vVO_2max )] performed in normoxia and normobaric hypoxia (3000 m simulate altitude) 1 week before, and during 14 days of normobaric hypoxia [196.2 ± 25.6 h (median: 200.8 h; range: 154.3-234.8 h) at 3000 m simulated altitude] in 10 well-trained distance runners (six males, four females). Venous blood was also analyzed for hepcidin after 2 days of normobaric hypoxia. Hemoglobin mass (Hb_mass ) was measured via CO rebreathing 1 week before and after 14 days of hypoxia. Hepcidin was suppressed after 2 (Cohen's d = -2.3, 95% confidence interval: [-2.9, -1.6]) and 14 days of normobaric hypoxia (d = -1.6 [-2.6, -0.6]). Hepcidin increased from baseline, 3 h post-exercise in normoxia (d = 0.8 [0.2, 1.3]) and hypoxia (d = 0.6 [0.3, 1.0]), both before and after exposure (normoxia: d = 0.7 [0.3, 1.2]; hypoxia: d = 1.3 [0.4, 2.3]). In conclusion, 2 weeks of normobaric hypoxia suppressed resting hepcidin levels, but did not alter the post-exercise response in either normoxia or hypoxia, compared with the pre-exposure response.

Vitamin B12 and folate deficiency in chronic heart failure

OBJECTIVE

To determine the prevalence, clinical correlates and the effects on outcome of vitamin B12 and folic acid levels in patients with chronic heart failure (HF).

METHODS

We studied an international pooled cohort comprising 610 patients with chronic HF. The main outcome measure was all-cause mortality.

RESULTS

Mean age of the patients was 68±12 years and median serum N-terminal prohormone brain natriuretic peptide level was 1801 pg/mL (IQR 705-4335). Thirteen per cent of the patients had an LVEF >45%. Vitamin B12 deficiency (serum level <200 pg/mL), folate deficiency (serum level <4.0 ng/mL) and iron deficiency (serum ferritin level <100 µg/L, or 100-299 µg/L with a transferrin saturation <20%) were present in 5%, 4% and 58% of the patients, respectively. No significant correlation between mean corpuscular volume and vitamin B12, folic acid or ferritin levels was observed. Lower folate levels were associated with an impaired health-related quality of life (p=0.029). During a median follow-up of 2.10 years (1.31-3.60 years), 254 subjects died. In multivariable proportional hazard models, vitamin B12 and folic acid levels were not associated with prognosis.

CONCLUSIONS

Vitamin B12 and folate deficiency are relatively rare in patients with chronic HF. Since no significant association was observed between mean corpuscular volume and neither vitamin B12 nor folic acid levels, this cellular index should be used with caution in the differential diagnosis of anaemia in patients with chronic HF. In contrast to iron deficiency, vitamin B12 and folic acid levels were not related to prognosis.

SDF-1 chemokine signalling modulates the apoptotic responses to iron deprivation of clathrin-depleted DT40 cells

We have previously deleted both endogenous copies of the clathrin heavy-chain gene in the chicken pre B-cell-line DT40 and replaced them with clathrin under the control of a tetracycline-regulatable promoter (Tet-Off). The originally derived cell-line DKO-S underwent apoptosis when clathrin expression was repressed. We have also described a cell-line DKO-R derived from DKO-S cells that was less sensitive to clathrin-depletion. Here we show that the restriction of transferrin uptake, resulting in iron deprivation, is responsible for the lethal consequence of clathrin-depletion. We further show that the DKO-R cells have up-regulated an anti-apoptotic survival pathway based on the chemokine SDF-1 and its receptor CXCR4. Our work clarifies several puzzling features of clathrin-depleted DT40 cells and reveals an example of how SDF-1/CXCR4 signalling can abrogate pro-apoptotic pathways and increase cell survival. We propose that the phenomenon described here has implications for the therapeutic approach to a variety of cancers.

Iron deficiency and health-related quality of life in chronic heart failure: results from a multicenter European study

Patients affected by chronic heart failure (CHF) present significant impairment of health-related quality of life (HRQoL). Iron deficiency (ID) is a common comorbidity in CHF with negative impact in prognosis and functional capacity. The role of iron in energy metabolism could be the link between ID and HRQoL. There is little information about the role of ID on HRQoL in patients with CHF. We evaluate the impact of ID on HRQoL and the interaction with the anaemia status, iron status, clinical baseline information and HRQoL, measured with the Minnesota Living with Heart Failure questionnaire (MLHFQ) was obtained at baseline in an international cohort of 1278 patients with CHF. Baseline characteristics were median age 68 ± 12, 882 (69%) were males, ejection fraction was 38% ± 15 and NYHA class was I/II/III/IV (156/247/487/66). ID (defined as ferritin level< 100 µg/L or serum ferritin 100-299 µg/L in combination with a TSAT<20%) was present in 741 patients (58%). 449 (35%) patients were anaemic. Unadjusted global scores of MLHFQ (where higher scores reflect worse HRQoL) were worse in ID and anaemic patients (ID+: 42 ± 25 vs. ID-: 37 ± 25; p-value=0.001 and A+: 46 ± 25 vs. A-: 37 ± 25; p-value<0.001). The combined influence of ID and anaemia was explored with different multivariable regression models, showing that ID but not anaemia was associated with impaired HRQoL. ID has a negative impact on HRQoL in CHF patients, and this is independent of the presence of anaemia.

The additive burden of iron deficiency in the cardiorenal-anaemia axis: scope of a problem and its consequences

AIMS

Iron deficiency (ID), anaemia, and chronic kidney disease (CKD) are common co-morbidities in chronic heart failure (CHF) and all independent predictors of unfavourable outcome. The combination of anaemia and CKD in CHF has been described as the cardiorenal-anaemia syndrome. However, the role of ID within this complex interplay of co-existing pathologies is unclear.

METHODS AND RESULTS

We studied the clinical correlates of ID (defined as ferritin <100 µg/L or 100-299 µg/L in combination with a transferrin saturation <20%, anaemia) and renal dysfunction (defined as estimated glomerular filtration rate <60 mL/min/1.73 m(2) ) and their prognostic implications in an international pooled cohort, comprising 1506 patients with CHF. Mean age was 64 ± 13 years, 74.2% were male, and 47.3% were in NYHA functional class III. The presence of ID, anaemia, CKD, or a combination of these co-morbidities was observed in 69.3% of the patients. During a median (Q1-Q3) follow-up of 1.92 years (1.18-3.26 years), 440 patients (29.2%) died. Eight-year survival rates decreased significantly from 58.0% for no co-morbidities to 44.6, 33.0, and 18.4%, for one, two, or three co-morbidities, respectively (P < 0.001). Multivariate hazard models revealed ID to be the key determinant of prognosis, either individually (P = 0.04) or in combination with either anaemia (P = 0.006), CKD (P = 0.03), or both (P = 0.02).

CONCLUSIONS

Iron deficiency frequently overlaps with anaemia and/or CKD in CHF. The presence of ID amplifies mortality risk, either alone or in combination with anaemia, CKD, or both, making it a potential viable therapeutic target.

Iron status and its relations with oxidative damage and bone loss during long-duration space flight on the International Space Station

BACKGROUND

Increases in stored iron and dietary intake of iron during space flight have raised concern about the risk of excess iron and oxidative damage, particularly in bone.

OBJECTIVES

The objectives of this study were to perform a comprehensive assessment of iron status in men and women before, during, and after long-duration space flight and to quantify the association of iron status with oxidative damage and bone loss.

DESIGN

Fasting blood and 24-h urine samples were collected from 23 crew members before, during, and after missions lasting 50 to 247 d to the International Space Station.

RESULTS

Serum ferritin and body iron increased early in flight, and transferrin and transferrin receptors decreased later, which indicated that early increases in body iron stores occurred through the mobilization of iron to storage tissues. Acute phase proteins indicated no evidence of an inflammatory response during flight. Serum ferritin was positively correlated with the oxidative damage markers 8-hydroxy-2'-deoxyguanosine (r = 0.53, P < 0.001) and prostaglandin F2α (r = 0.26, P < 0.001), and the greater the area under the curve for ferritin during flight, the greater the decrease in bone mineral density in the total hip (P = 0.031), trochanter (P = 0.006), hip neck (P = 0.044), and pelvis (P = 0.049) after flight.

CONCLUSION

Increased iron stores may be a risk factor for oxidative damage and bone resorption.

Iron deficiency in chronic heart failure: an international pooled analysis

BACKGROUND

Iron deficiency (ID) is an emerging problem in patients with chronic heart failure (HF) and can be a potential therapeutic target. However, not much is known about the prevalence, predictors, and prognosis of ID in patients with chronic HF.

METHODS

In an international pooled cohort comprising 1,506 patients with chronic HF, we studied the clinical associates of ID and its prognostic consequences.

RESULTS

Iron deficiency (defined as a ferritin level <100 μg/L or ferritin 100-299 μg/L with a transferrin saturation <20%) was present in 753 patients (50%). Anemic patients were more often iron deficient than nonanemic patients (61.2% vs 45.6%, P < .001). Other independent predictors of ID were higher New York Heart Association class, higher N-terminal pro-brain-type natriuretic peptide levels, lower mean corpuscular volume levels, and female sex (all P < .05). During follow-up (median 1.92 years, interquartile range 1.18-3.26 years), 440 patients died (29.2%). Kaplan-Meier survival analysis revealed ID as a strong predictor for mortality (log rank χ(2) 10.2, P = .001). In multivariable hazard models, ID (but not anemia) remained a strong and independent predictor of mortality (hazard ratio 1.42, 95% confidence interval 1.14-1.77, P = .002). Finally, the presence of ID significantly enhanced risk classification and integrated discrimination improvement when added to a prediction model with established risk factors.

CONCLUSIONS

Iron deficiency is common in patients with chronic HF, relates to disease severity, and is a strong and independent predictor of outcome. In this study, ID appears to have greater predictive power than anemia.

Analysis of red cell parameters on the Sysmex XE 2100 and ADVIA 120 in iron deficiency and in uraemic chronic disease

OBJECTIVE

The percentage measurement of hypochromic red cells (HYPO) and reticulocyte haemoglobin content (CHr) using the ADVIA system has recently been validated as a useful tool in indicating iron deficiency, also in cases of chronic diseases such as renal failure. The aim of this study was to evaluate the extent to which the red cell parameters, RBC-Y and RET-Y, provided by Sysmex XE 2100, correlate with HYPO and CHr.

MATERIAL AND METHODS

The laboratory markers of iron status were evaluated together with HYPO, CHr, RBC-Y and RET-Y in 92 healthy subjects (C), 42 iron-deficient patients (ID) and 88 uraemic patients receiving regular dialysis treatment (RDT).

RESULTS

In ID patients, increased HYPO and decreased RBC-Y, CHr and RET-Y values, with no overlapping with reference values, were found and a significant correlation was present between ADVIA 120 and Sysmex indices (p<0.001 for each correlation). In RDT patients, HYPO median values were increased with a wide distribution of values (95 % reference range = 0.7-27.5 % and 0.7-22.6 % in men and women, respectively). In contrast, RBC-Y was normal/increased (95 % reference range = 169.4-191.1 and 168.7-190.5 in men and women, respectively), even though there was a significant correlation between them (p<0.001). CHr and RET-Y values were within the reference range; moreover, in these patients mean cell volume of red cells and of reticulocytes (MCV and MCVr) median values were increased.

CONCLUSIONS

This study confirmed the validity of RBC-Y in the management of ID, but not in RDT, where the diagnostic power of RBC-Y as an index of cell hypochromia is limited owing to high MCV values.

High nontransferrin bound iron levels and heart disease in thalassemia major

Although the presence of nontransferrin bound plasma iron (NTBI) in transfusional iron overload is well documented, knowledge about its clinical significance is limited. We assessed NTBI levels in a large and homogeneous series of thalassemia patients on regular transfusion and chelation and explored the hypothesis that NTBI levels may be associated with relevant clinical outcomes: in particular, heart disease. Among 174 patients with thalassemia major and intermedia, we showed the presence NTBI in 145 of 174 or 83.3% of cases. NTBI levels correlated with transferrin saturation, age, and ALT, and not with serum ferritin or liver iron concentrations. At a multiple regression analysis, transferrin saturation and heart disease but not age was independent predictors of NTBI. Patients with heart disease had NTBI levels significantly higher than those without. All patients with heart disease had transferrin saturation above 70%, and all were NTBI positive. Conversely, none of the patients without NTBI and/or with transferrin saturation less than 70% had preclinical or clinical heart disease. To our knowledge, this is the first documentation of a link between the presence of NTBI in thalassemic patients with transfusional iron overload and heart disease. Further investigation from these preliminary findings may clarify whether NTBI assessment may have a role in evaluating the risks and optimizing treatment for transfusion-dependent patients.

Performance characteristics of the Dimension RxL iron and total iron-binding capacity methods

BACKGROUND

Measurements of serum iron and total iron-binding capacity (TIBC) can be used to aid the diagnosis of iron deficiency and iron overload states. A variety of different methods for these measurements are commercially available.

METHODS

Linearity, imprecision and hemoglobin interference of homogeneous iron and TIBC methods on a Dimension RxL analyzer were assessed. Method comparison studies were performed with a Vitros 950 analyzer.

RESULTS

The Dimension RxL iron method was linear from 40 to 1000 microg/dl. The coefficient of variation of the iron and TIBC methods were <4% and <2%, respectively, at iron concentrations of 68 and 228 microg/dl and TIBC concentrations of 206 and 384 microg/dl. Comparison of the Vitros 950 and Dimension RxL iron methods gave a slope of 0.97, an intercept of 6.0 and r=0.99. Corresponding results for the TIBC methods were 1.02, -6.6 and r=0.97, respectively. Simulation of acute iron overload in vitro did not produce the same effect on TIBC measurements as in vivo overload. Iron recovery by the Dimension RxL method was reduced 40-60% by the addition of deferoxamine at a concentration of 200 micromol/l.

CONCLUSIONS

The Dimension RxL assay provides acceptable measurements of iron and TIBC in routine patient samples. Iron measurements are unreliable in the presence of deferoxamine.

Total iron binding capacity and transferrin concentration in the assessment of iron status

Transferrin concentration and total iron binding capacity (TIBC) are currently used to assess iron status. Although correlation between TIBC and transferrin is generally considered as good, conversion factors between the two analytes found in literature show large differences. Although the price per test is lower for TIBC, there are a number of analytical advantages of serum transferrin. Due to binding of iron to other plasma proteins (mainly albumin), TIBC methods generally overestimate the iron binding capacity of transferrin. Moreover, no generic reference values are available for TIBC. In contrast to TIBC, internationally accepted interim reference ranges are available for serum transferrin. The introduction of the international CRM 470 protein standard material has lead to a significant reduction in interlaboratory variation for transferring measurements. In view of these observations, determination of transferrin concentration, rather than TIBC, is recommended. However, in non-European populations characterized by a marked genetic variation in transferrin (TF BC and TF CD variants), in certain cases, immunochemical determination of transferrin may lead to errors. In these populations, TIBC measurements may be preferred.

Reference distributions for serum iron and transferrin saturation: a comparison of a large cohort to the world's literature

The appropriate clinical use of serum iron and transferrin saturation (TSAT) requires satisfactory reference intervals from birth to old age, and for males and females. This study identified 54 publications from 1974 to 2001 that met the criteria used in three prior meta-analyses, and these were analyzed statistically. A summary of our review is presented along with our reference population data on these measurements. This analysis places previous publications in perspective and suggests possible reasons for the observed differences. Previous studies of the individual analytes, serum iron, transferrin, and TSAT values agree with the reference ranges presented in this study, although the entire experience over time and between sexes has not been available before. Our 95% reference ranges are somewhat broader than those of the smaller studies, but they agree well with those of the larger ones.

Bleomycin-detectable Iron Assay for Non-Transferrin-bound Iron in Hematologic Malignancies

Background: A microwell modification of the bleomycin assay for determining non-transferrin-bound iron (NTBI) was evaluated and compared with a chelation method.

Methods: The bleomycin assay reagent and sample volumes were halved, and measurements were done in microwell plates. Samples from patients treated for hematologic malignancies were studied. The chelation method was based on mobilization of NTBI with a chelator and measurement of the ultrafiltered iron-chelator complex. NTBI results were also compared with transferrin saturation and the distribution of transferrin iron forms by urea-polyacrylamide gel electrophoresis.

Results: The bleomycin assay intraassay imprecision (CV) was 7.7% and 8.2% and the interassay imprecision was 18% and 9.8% for a low (0.2 μmol/L) and a high (1.5 μmol/L) control, respectively. Hemolysis increased measured NTBI. A detection limit of 0.1 μmol/L was established based on the interference of nonvisible hemolysis and on accuracy studies. In patient samples, NTBI exceeded the detection limits only when transferrin saturation was &gt;80%. Compared with the chelation method, the bleomycin assay gave clearly lower NTBI concentrations. The chelation method also gave positive results at &lt;80% transferrin saturation. The recovery of iron added as ferric nitrilotriacetate to serum was 33% by the bleomycin assay and 64% by the chelation assay.

Conclusions: The microwell version of the bleomycin assay is reproducible. When hemolyzed samples were excluded, bleomycin-detectable iron was found only when the transferrin saturation was &gt;80%, suggesting high specificity. Bleomycin-detectable iron constitutes only a portion of the NTBI measured by the chelation method.

Direct Serum Total Iron-binding Capacity Assay Suitable for Automated Analyzers

Background: Present methods for measuring serum total iron-binding capacity (TIBC) involve manipulation of samples or performance of two assays on each sample. We developed a direct automated assay (DTIBC) for TIBC.

Methods: We added to serum a saturating amount of iron bound to an excess of chelating dye at a low pH, recorded a blank reading that represented the sum of the saturating amount of iron plus the serum iron, and then added a strong neutral pH buffer. The decrease in absorbance (as transferrin extracts iron from the iron-dye complex) is directly proportional to the TIBC. TIBC values for 125 patients were determined by DTIBC, alumina column TIBC (AC), magnetic particle TIBC (MTIBC), and the UIBC method (UIBC) on Roche COBAS FARA and Mira chemistry analyzers. In a separate study, TIBC values for 128 patients were determined on an Olympus AU400 by the DTIBC and the MTIBC methods.

Results: Methods comparisons on the COBAS analyzers yielded the following results: DTIBC = 1.05(MTIBC) − 1.0 μmol/L (r = 0.987; Sy|x = 2.6 μmol/L); DTIBC = 1.07(AC) − 1.0 μmol/L (r = 0.982; Sy|x = 3.0 μmol/L); and DTIBC = 1.14(UIBC) + 3.4 μmol/L (r = 0.982; Sy|x = 3.0 μmol/L). A similar correlation study using the Olympus AU400 yielded DTIBC = 1.00(MTIBC) − 0.1 μmol/L (r = 0.983; Sy|x = 2.7 μmol/L). The assay was linear from 12.5 to 125 μmol/L (70–700 μg/dL) TIBC on the COBAS FARA. Within- and between-run imprecision (CV) was ≤4.8% at two concentrations. Plasma samples were unsuitable for the method. No interference was seen with common interferants other than ascorbate, deferoxamine, and ferrous sulfate, and only at concentrations well above normal.

Conclusion: The new DTIBC assay is suitable for routine use in clinical laboratories and may improve the quality of iron metabolism studies.

MCV as a guide to phlebotomy therapy for hemochromatosis

BACKGROUND

A multitude of recommendations exist for laboratory assays to monitor the pace and endpoints of phlebotomy therapy for hemochromatosis. All of these recommendations rely on an assessment of storage iron to guide treatment, and none have been prospectively evaluated.

STUDY DESIGN AND METHODS

Nine consecutive patients underwent serial monitoring of Hb, MCV, transferrin saturation, and ferritin during weekly phlebotomy to deplete iron stores (induction therapy) and less frequent sessions to prevent iron reaccumulation (maintenance therapy). Changes in MCV and Hb were used to guide the pace of phlebotomy over a median of 7 years of follow-up.

RESULTS

During induction therapy, the MCV increased transiently because of reticulocytosis and then stabilized for a prolonged period before decreasing more sharply, which reflected iron-limited erythropoiesis. Iron depletion was achieved after a median of 38 phlebotomies and removal of 9.0 g of iron. Maintenance phlebotomy was targeted to maintain the MCV at 5 to 10 percent below prephlebotomy values and the Hb at >13 g per dL. Transferrin saturation fluctuated considerably during treatment, but remained below 35 percent during MCV-guided maintenance therapy. Ferritin values were not useful guides to the pace of phlebotomy. The median maintenance therapy phlebotomy interval was 7.5 weeks (range, 6-16), which corresponded to an average daily iron removal of 35 to 67 microg per kg. Most patients showed evidence of iron reaccumulation at phlebotomy intervals of 8 weeks or more.

CONCLUSION

The MCV is an inexpensive, precise, physiologic indicator of erythropoietic iron availability. When used in conjunction with the Hb, it is a clinically useful guide to the pace of phlebotomy therapy for hemochromatosis.

Low frequency of elevated serum transferrin saturation in elderly subjects

Serum transferrin saturation (TS) values were calculated on the basis of serum iron and transferrin (protein) measurements in a total of 2425 serum samples from six groups of subjects: individuals applying for selection as blood donors (M and F, median age 34 and 32 years); patients referring to the hospital laboratory for routine testing (M and F, median age 45 and 48 years); and elderly subjects living in a specialized institute (M and F, median age 76 and 82 years). In the first four groups the frequency of TS values <15% and >62% respectively, was substantially as expected, considering the average health conditions and sex. These results indirectly support the reliability of the measurement procedure. In the elderly group, however, the frequency of TS values >62% was zero. Mean TS values in the elderly group (males and females) were significantly lower (P<0. 0001) than in the blood donors group and in the hospital patients one. This observation suggests a shortened survival in the presence of (unrecognized) iron overload, pointing out at the usefulness of iron overload screening using simple biochemical tests.

Total iron-binding capacity and serum transferrin determination under the influence of several clinical conditions

In this study TIBC and serum-transferrin concentrations were determined by immunochemical turbidimetry, immunochemical nephelometry and radial immunodiffusion under normal and pathological clinical conditions. A total of 246 (123 male/123 female) patients were included [iron deficiency: 60 (18/42), iron overload: 56 (39/17), chronic inflammation: 47 (23/24), undefined diseases: 35 (16/19), healthy volunteers 48 (27/21)]. The data show that determination of TIBC from conversion of transferrin values using a constant factor results in significantly higher values compared to conversion with a function of first degree. For clinical practice the influence of different diseases is negligible. This study indicates that it is not possible to develop a universal algorithm for the conversion of transferrin values into TIBC.

A population-based study of the clinical expression of the hemochromatosis gene

BACKGROUND AND METHODS

Hereditary hemochromatosis is associated with homozygosity for the C282Y mutation in the hemochromatosis (HFE) gene on chromosome 6, elevated serum transferrin saturation, and excess iron deposits throughout the body. To assess the prevalence and clinical expression of the HFE gene, we conducted a population-based study in Busselton, Australia. In 1994, we obtained blood samples for the determination of serum transferrin saturation and ferritin levels and the presence or absence of the C282Y mutation and the H63D mutation (which may contribute to increased hepatic iron levels) in 3011 unrelated white adults. We evaluated all subjects who had persistently elevated transferrin-saturation values (45 percent or higher) or were homozygous for the C282Y mutation. We recommended liver biopsy for subjects with serum ferritin levels of 300 ng per milliliter or higher. The subjects were followed for up to four years.

RESULTS

Sixteen of the subjects (0.5 percent) were homozygous for the C282Y mutation, and 424 (14.1 percent) were heterozygous. The serum transferrin saturation was 45 percent or higher in 15 of the 16 who were homozygous; in 1 subject it was 43 percent. Four of the homozygous subjects had previously been given a diagnosis of hemochromatosis, and 12 had not. Seven of these 12 patients had elevated serum ferritin levels in 1994; 6 of the 7 had further increases in 1998, and 1 had a decrease, although the value remained elevated. The serum ferritin levels in the four other homozygous patients remained in the normal range. Eleven of the 16 homozygous subjects underwent liver biopsy; 3 had hepatic fibrosis, and 1, who had a history of excessive alcohol consumption, had cirrhosis and mild microvesicular steatosis. Eight of the 16 homozygous subjects had clinical findings that were consistent with the presence of hereditary hemochromatosis, such as hepatomegaly, skin pigmentation, and arthritis.

CONCLUSIONS

In a population of white adults of northern European ancestry, 0.5 percent were homozygous for the C282Y mutation in the HFE gene. However, only half of those who were homozygous had clinical features of hemochromatosis, and one quarter had serum ferritin levels that remained normal over a four-year period.

Diagnosis of iron deficiency in chronic renal failure

The cause of anemia in chronic renal failure is multifactorial. Decreased erythropoietin (EPO) production is the main pathogenetic factor, but iron deficiency is the primary cause of unresponsiveness to EPO therapy. The diagnosis of iron deficiency in patients with chronic renal failure is difficult. We assessed the sensitivity and specificity of serum ferritin, total iron-binding capacity, transferrin saturation index, erythrocyte ferritin, and serum transferrin receptor in 63 patients with chronic renal failure undergoing dialysis (47 men, 16 women) with iron deficiency anemia. They were selected on the basis of clinical stability and absence of factors that may interfere with iron metabolism. None of the patients had received intravenous iron therapy or recombinant human erythropoietin (rHuEPO). Bone marrow biopsy with iron staining was the reference standard for iron stores. The receiver operating characteristic (ROC) curve and the area under the curve were calculated to assess the sensitivity and specificity of iron metabolism parameters. The parameter with the largest area under the ROC curve was serum ferritin (0.83). A cut point of 121 microgram/L showed a sensitivity and a specificity of 75%. The areas under the ROC curves of serum transferrin receptor and erythrocyte ferritin were 0.69 and 0.68, respectively. The remaining parameters showed areas under the ROC curve less than 0.65. Although serum transferrin receptor and erythrocyte ferritin may be acceptable markers for iron deficiency in stable chronic renal failure patients, serum ferritin level continues to be the most reliable diagnostic parameter. Transferrin saturation index is not a reliable parameter for the diagnosis of iron deficiency in stable patients not treated with rHuEPO.

Hereditary haemochromatosis: diagnosis and management in the gene era

Hereditary haemochromatosis is a common inherited disorder of iron metabolism in Caucasian populations. Two mutations in the HFE gene are strongly associated with hereditary haemochromatosis. One of these mutations (Cys282-->Tyr; C282Y) is found homozygous in 90-95% of subjects with typical hereditary haemochromatosis. A second mutation (His63-->Asp; H63D) has also been identified but is not associated with the same degree of iron overload as with the C282Y mutation. About 20% of subjects who are heterozygous for both mutations (C282Y, H63D-compound heterozygotes) can express typical hereditary haemochromatosis. A large number of patients with early disease are asymptomatic, and prompt diagnosis and treatment can result in normal life expectancy. The diagnosis can readily be confirmed by serum iron studies and genetic testing. For C282Y homozygotes or compound heterozygotes diagnosed under the age of 40 years and with no biochemical or clinical evidence of liver disease, phlebotomy therapy can be initiated without the need for liver biopsy. Liver biopsy should still be considered in all other patients with iron overload. Screening of first degree relatives should now be based on genotype assessment and measurement of serum iron parameters in order to determine phenotypic expression of the disease.

Elevated non-transferrin bound iron in the lungs of patients with Pneumocystis carinii pneumonia

OBJECTIVE

The aim of the present work was to determine the concentrations of iron and iron-binding proteins in the lungs of patients suffering from Pneumocystis carinii (PCP), which is crucial for justifying the treatment with iron-chelating agents in this disease.

PATIENTS AND METHODS

Bronchoalveolar lavage was performed in 10 HIV patients with PCP and five healthy controls. Total iron and iron-binding proteins (transferrin, ferritin and lactoferrin) were measured in acellular bronchoalveolar lavage fluid (BALF) in both groups. Iron was determined by atomic absorption spectrometry; transferrin and lactoferrin were measured using specific enzyme-linked immunosorbent assays (ELISA); and ferritin concentration was quantified by automated immunonephelometry.

RESULTS

Our findings in patients with PCP demonstrated a six- to seven-fold increase of total iron levels and an eight-fold increase of ferritin in bronchoalveolar lavage fluid when compared with controls. No significant differences were found in transferrin or lactoferrin levels. Moreover, our results suggest that this iron is non-transferrin bound.

CONCLUSION

Non-transferrin bound iron is increased in the lower respiratory tracts of PCP patients. This finding would lend experiment support to the use of iron-chelating agents in this disease.

The relation between chemically measured total iron-binding capacity concentrations and immunologically measured transferrin concentrations in human serum

We sought to determine if serum total iron-binding capacity (TIBC) is equivalent to serum transferrin (TRF) so that a low-cost colorimetric chemical assay for unsaturated iron-binding capacity (UIBC) could be substituted for a high-cost immunologic assay for TRF. Our study design included independent and blinded measurements of UIBC, serum iron, and TRF concentrations in human serum samples. Data from five independent correlation studies carried out at three different Quest Diagnostics laboratories were combined into one data set containing 570 paired results for TIBC and TRF. r2 was 0.941 when three outliers were eliminated from the 570-sample data set. Scatter about the regression line was fully accounted for by the CVs for the TIBC and TRF assays. When each test is measured precisely and without bias, the ratio of TIBC (μmol/L) to TRF (g/L) in SI units is close to the theoretically expected value of 25.0.

Serum Transferrin Receptor and Its Ratio to Serum Ferritin in the Diagnosis of Iron Deficiency

The objective of the study was to evaluate the diagnostic efficiency of laboratory tests, including serum transferrin receptor (TfR) measurements, in the diagnosis of iron depletion. The patient population consisted of 129 consecutive anemic patients at the University Hospital of Turku who were given a bone marrow examination. Of these patients, 48 had iron deficiency anemia (IDA), 64 anemia of chronic disease (ACD), and 17 patients had depleted iron stores and an infectious or an inflammatory condition (COMBI). Depletion of iron stores was defined as a complete absence of stainable iron in the bone marrow examination. Serum TfR concentrations were elevated in the vast majority of the IDA and COMBI patients, while in the ACD patients, the levels were within the reference limits reported earlier for healthy subjects. TfR measurement thus provided a reliable diagnosis of iron deficiency anemia (AUCROC 0.98). Serum ferritin measurement also distinguished between IDA patients and ACD patients. However, the optimal decision limit for evaluation of ferritin measurements was considerably above the conventional lower reference limits, complicating the interpretation of this parameter. Calculation of the ratio TfR/log ferritin (TfR-F Index) is a way of combining TfR and ferritin results. This ratio provided an outstanding parameter for the identification of patients with depleted iron stores (AUCROC 1.00). In anemic patients, TfR measurement is a valuable noninvasive tool for the diagnosis of iron depletion, and offers an attractive alternative to more conventional laboratory tests in the detection of depleted iron stores.

Practice guideline development task force of the College of American Pathologists. Hereditary hemochromatosis

Hereditary hemochromatosis is an autosomal recessive disorder, the gene for which occurs in approximately 10% of Americans, most of whom are unaffected heterozygotes. Approximately 5/1000 white Americans are homozygous and at risk of developing severe and potentially lethal hemochromatosis. The disorder affects numerous organ systems, but the most common symptoms are fatigue, palpitations, joint pains, and impotence; the most common signs are those that relate to hypothalamic, cardiac, hepatic or pancreatic dysfunction, including poor cold tolerance, impotence in males, amenorrhea in females, cardiac arrhythmias, dyspnea, edema, hepatosplenomegaly, spider telangiectases, ascites, deformity, swelling or limitation of motion of joints, weight loss, hyperpigmentation. Characteristic abnormalities of laboratory tests include elevated serum iron concentration, high transferrin saturation, elevated serum ferritin concentration, elevated serum transaminases, hyperglycemia and low values for thyroid-stimulating hormone (TSH) and gonadotropins. Death may be the result of cardiac arrhythmia, congestive heart failure, liver failure or liver cancer. Since many of these complications cannot be reversed once they have developed, early diagnosis and treatment are essential. In view of the high prevalence in the American population (prevalence varies with ethnic background), the low cost of diagnosis and treatment, the efficacy of treatment if begun early, and, on the other hand, high costs and low success rate of late diagnosis and treatment, systematic screening for hemochromatosis is warranted for all persons over the age of 20 years. The initial screening should be by measurement of serum iron concentration and transferrin saturation. The practice guideline provides a diagnostic algorithm for cases in which the serum transferrin saturation is 60% or greater. It also provides guidelines for clinical management.

Pediatric gastroenterology. Update on metabolic liver disease

Wilson's disease, genetic and neonatal hemochromatosis, protoporphyria, tyrosinemia, and alpha1-antitrypsin deficiency are updated. Cost effectiveness of screening is discussed. Current therapies are evaluated, including the role of transplantation. The molecular biologic technique PCR is covered. Gene therapy is introduced.

Measured versus calculated latent iron binding capacity in plasma of newborns

Iron overload as well as iron deficiency may play a role in the pathogenesis of diseases in the newborn and infant and therefore knowledge of the iron status is essential. Using an automated method for the determination of plasma latent iron-binding capacity (LIBC) we measured the LIBC in 20 full term and 20 preterm babies and 20 adults. LIBC was also calculated from transferrin and iron concentration.

Gallium 67 in the human lymphoid cell line U-715: uptake, cytotoxicity and intracellular localization

The selective uptake of the Auger- and internal conversion electrons emitting radionuclide 67Ga in malignant tumours may have therapeutic potential. We studied several factors which might affect the uptake and radiotoxicity of 67Ga in the human lymphoma cell line U-715. The 67Ga uptake was dependent on transferrin in a dose-dependent manner. The highest 67Ga uptake was found in the presence of 50 micrograms/ml purified human transferrin. Serum components other than transferrin negatively influenced the 67Ga uptake. Cells were adapted to a serum-free medium in which cells could be maintained for months and without factors disturbing 67Ga uptake. We demonstrated that there was a positive correlation between cell viability and 67Ga uptake (r = 0.97). Preculturing of cells in iron- and transferrin-deficient medium prior to 67Ga uptake led to upregulation of the transferrin receptor and a three-fold increase of 67Ga uptake. Uptake in these cells could be blocked by 72% by anti-transferrin-receptor monoclonal antibodies. Autoradiography of U-715 cells after 67Ga incubation showed intracellular 67Ga both in the cytoplasm and nucleus. Cell fractionation of 67Ga-loaded cells showed 27% of 67Ga present in the nuclei. Culturing of cells for 4 days in the presence of 3 MBq/ml 67Ga resulted in a 45% decrease of cell proliferation. The clonogenic capacity was diminished by 91%. In conclusion, we have demonstrated that 67Ga uptake is a transferrin-receptor-dependent mechanism of vital cells, and that after uptake 67Ga enters the cytosol and nucleus and has a strong cytotoxic effect on clonogenic capacity.