Serum transferrin receptor in polycythemia

We measured serum transferrin receptor (sTfR) levels in 22 patients with polycythemia vera and in 26 cases of secondary polycythemia. In our study, raised sTfR levels in both polycythemia groups were related to iron deficiency.     

Serum transferrin receptor concentration is not indicative of erythropoietic activity in chronic hemodialysis patients with poor response to recombinant human erythropoietin

BACKGROUND: Serum transferrin receptor (sTfR) is a transmembrane glycoprotein derived from erythroid precursors in the bone marrow. Its concentration provides a quantitative measure of total erythropoietic activity and an indication of functional iron deficiency. This study was conducted to investigate whether sTfR is a useful index of erythropoietic activity in chronic hemodialysis patients with poor response to maintenance recombinant human erythropoietin (rHuEPO) therapy. METHODS: Using an enzyme-linked immunosorbent assay, sTfR concentration was measured in 67 uremic patients who had been on hemodialysis for a mean of 42 months (3-242 months). rHuEPO was administered three times a week to keep the hematocrit above 30%. Hemoglobin, red blood cell indices, serum ferritin, serum total iron binding capacity and unsaturated iron binding capacity were determined. Of the 67 patients, 35 who responded favorably to rHuEPO with hematocrits above 30% were categorized as Group I and 32 who did not attain the target hematocrit were categorized as Group II. As a control group, 31 healthy subjects were also investigated. RESULTS: The serum iron, ferritin, transferrin iron saturation, dialysis efficiency and nutritional state were not different between groups of hemodialysis patients. The mean sTfR concentration was 2.1 +/- 0.6 micrograms/ml (range, 1.15-3.53 micrograms/ml) in Group I patients, compared with 1.9 +/- 0.9 micrograms/ml (range, 1.03-2.65 micrograms/ml) in Group II. The difference was not significant. In addition, the mean sTfR concentration of 1.8 +/- 0.4 micrograms/ml (range, 0.86-2.76 micrograms/ml) in the healthy controls was not significantly different from Groups I and II. CONCLUSIONS: sTfR concentration cannot be used to distinguish good from poor rHuEPO responders among chronic hemodialysis patients who have elevated serum ferritin (> 300 micrograms/l) and transferrin iron saturation (> 25%) during the course of maintenance rHuEPO therapy.     

Clinico-radiological correlation in thalassemia intermedia

Fifteen thalassemia intermedia patients were considered, whose clinical and radiological findings were examined and compared. Eight patients underwent regular transfusion therapy. All patients underwent total body CT: the volume of ectopic erythropoiesis foci was calculated by a digital calculation algorithm (ROI volume). This work was aimed at correlating the quantitative measures of ectopic erythropoiesis assessed by CT with serum level of erythropoietin (EPO) and of trasferrin-free receptors (TfR) in both transfused and non-transfused patients, also considering the volume changes of ectopic erythropoiesis and bone changes over 36 months' follow-up. A direct correlation was demonstrated between serum transferrin and ectopic erythropoietic masses in transfusion-dependent patients: in fact, increased values of serum transferrin correspond to the enlargement of these masses and to bone lesion worsening.     

Serum transferrin receptor and transferrin receptor-ferritin index identify healthy subjects with subclinical iron deficits

Despite the established utility of serum transferrin receptor (sTfR), serum ferritin, and the sTfR/log ferritin ratio (TfR-F Index) in the diagnosis of iron deficiency (ID) anemia, the numeric values of these parameters, which are indicative of subclinical ID, remain to be clearly defined. In this study, 65 apparently healthy nonanemic adults (22 men and 43 women) were treated with 3 months of oral iron supplementation to evaluate its effect on parameters reflecting iron status and to determine the prevalence of subclinical iron deficiency in apparently healthy adults. Significant supplementation-induced changes were observed in sTfR, ferritin, and TfR-F Index values in women, whereas in men, none of the studied parameters showed any significant change. Iron-deficient erythropoiesis (IDE) was not observed in men, but was found in 17 women (40%). Although individuals with a compromised iron status may be represented in substantial numbers in conventional reference populations, they can be readily identified using sTfR, ferritin, and TfR-F Index determinations.     

Early prediction of response to recombinant human erythropoietin in patients with the anemia of renal failure by serum transferrin receptor and fibrinogen

Recombinant human erythropoietin (rHuEpo) has been shown to be effective in correcting the anemia of chronic renal failure, but the dose needed may be variable. The reason for this variation is not known, but several factors could be involved, such as iron deficiency, inflammation, aluminum intoxication, hyperparathyroidism, blood losses, or marrow dysfunction. Treatment with rHuEpo was given intravenously thrice weekly after hemodialysis to 64 consecutive unselected patients with the anemia of chronic renal failure. The starting dose was 50 U/kg/dose, which was increased to 75 and 100 U/kg/dose if no response was observed after 1 and 2 months of treatment. After a minimum follow-up of 6 months, response was evaluated as early (hematocrit [Hct] > or = 30% before 3 months) or late (Hct > or = 30% after 3 months) response, or failure (target Hct not attained). We examined the value of various laboratory parameters (baseline values and early changes) as predictors of response to rHuEpo. The best prediction by pretreatment parameters only was obtained with baseline serum transferrin receptor (TfR) (< or > or = 3,500 ng/mL) and fibrinogen (< or > or = 4 g/L): 100% response rate when both parameters were low, versus only 29% when they were both high, and versus 67% when one was low and the other high. When the 2-week TfR increment was greater than 20%, the response rate was 96%. When TfR increment was less than 20%, the response rate was 100% when baseline TfR and fibrinogen were low, 12% when fibrinogen was elevated, and 62% when fibrinogen was low but baseline TfR high. The predictive value of baseline TfR and fibrinogen and of the 2-week increment of TfR was confirmed by life table analysis and stepwise discriminant analysis. Major reasons for failure or late response were identified and included subclinical inflammation, iron deficiency, functional iron deficiency, marrow disorders, hemolysis, bleeding, and low Epo dose. We conclude that response to rHuEpo can be predicted early by pretreatment fibrinogen and TfR, together with early changes of TfR levels. These prognostic factors illustrate the importance of the early erythropoietic response, subclinical inflammation, and functional iron deficiency. Early recognition of a low probability of response in a given patient could help identify and correct specific causes of treatment failure to hasten clinical improvement and avoid prolonged ineffective use of an expensive medication.     

Correlation between soluble transferrin receptor and serum ferritin levels following bone marrow transplantation for thalassemia

This study analyzes the serum transferrin receptor (sTfR) levels in a series of 230 ex-thalassemics with a follow-up of 1 to 9 years after bone marrow transplantation (BMT) for homozygous beta thalassemia. Ex-thalassemics are individuals, cured of homozygous beta thalassemia by BMT, who maintain different degrees of iron overload acquired during the pretransplant period. Both in experimental and clinical conditions, sTfR concentrations have been shown to be a quantitative measure of body iron status. This study was carried out to assess whether the level of sTfR may be of help in determining the extent of iron overload in ex-thalassemics. Patients who received the marrow from their HLA-identical sibling donor heterozygous for beta thalassemia, namely heterozygous ex-thalassemics, displayed significantly higher levels of sTfR than patients transplanted from their normal sibling donors (normal ex-thalassemics). This finding suggests that increased erythropoiesis, albeit in part ineffective in heterozygous ex-thalassemics, is responsible for the sTfR increment. Both heterozygous and normal ex-thalassemics had significant lower sTfR levels than their heterozygous (p < 0.003) or normal (p < 0.0001) donors, respectively. These differences may be ascribed to the presence of iron overload in ex-thalassemics in comparison to their normal or heterozygous donors who did not present excess of iron in the body. A significant inverse correlation between sTfR and serum ferritin levels (r = -0.54, p < 0.0001) was found when normal ex-thalassemics were considered. In heterozygous ex-thalassemics, the lack of correlation between these two parameters may be explained by the enhanced erythropoietic activity of individuals with thalassemic trait. These results suggest that the level of sTfR may be a useful indicator of iron overload in normal ex-thalassemics.     

Characterization of circulating erythrocytes from myelodysplastic patients treated with recombinant human erythropoietin

Age-density fractionation, in-vitro erythrophagocytosis, and enumeration of membrane-bound antibodies were monitored for circulating red blood cells (RBC) from five anemic patients with myelodysplastic syndromes (MDS), in relation to administration of recombinant human erythropoietin (rhEPO). The density distribution patterns of erythrocytes from the patients prior to treatment were in accordance with their inability to produce compensating levels of circulating RBC. The complete response of one patient to rhEPO and partial responses of two other patients were accompanied by shifts to larger proportions of low density (young) RBC. In vitro phagocytosis of density-fractionated RBC from the complete responder was similar to those of age-matched non-anemic donors. Elevated erythrophagocytosis prior to rhEPO administration was observed for the partial responders and further increased during treatment in one, suggesting the stimulation of abnormal progenitors producing highly defective erythrocytes. There was no correlation between levels of erythrophagocytosis and RBC membrane-bound immunoglobulins in this group of patients. Our findings suggest that density distribution analysis of circulating RBC coupled with in vitro erythrophagocytosis may provide useful predictive tools for selecting potential responders to rhEPO administration among anemic MDS patients.     

Modifications of erythropoiesis in myelodysplastic syndromes treated with recombinant erythropoietin as evaluated by soluble transferrin receptor, high fluorescence reticulocytes and hypochromic erythrocytes

BACKGROUND: The aim of this study was to evaluate changes in erythropoiesis induced in vivo by recombinant erythropoietin (r-EPO) treatment in myelodysplastic syndromes (MDS), by means of some new, non invasive laboratory parameters. PATIENTS AND METHODS: Serum levels of soluble transferrin receptor (STR), a marker of total marrow erythroid activity, and automated detection of high fluorescence reticulocytes (HFR) and hypochromic erythrocytes (HE) (respectively, indexes of effective erythropoiesis and functional iron deficiency) were longitudinally measured in 25 MDS patients treated with r-EPO, and then correlated with conventional clinical and laboratory features. RESULTS: Stimulation of erythropoiesis was documented in 8 patients, whose serum STR levels showed a significant, early (within 16 days) increase during treatment with r-EPO. However, only 3 of these patients demonstrated a concomitant rise in HFR, and these were the only subjects who experienced a significant clinical response. Two of these patients also developed a functional iron deficiency while on treatment, as documented by an increase in HE, despite normal serum iron, transferrin saturation and even very high levels of ferritin. They needed iron supplementation to maintain the response to r-EPO. No variation in STR, HFR or HE occurred in the remaining 17 unresponsive patients during at least two months of treatment. Serum levels of thymidine kinase, as aspecific marker of cellular proliferative activity, paralleled those of STR. No correlation was found between STR, HFR or HE and serum levels of endogenous EPO, hemoglobin or transfusion requirements in MDS patients. CONCLUSIONS: These findings suggest that there is a heterogeneous and complex pattern of erythroid response in MDS patients treated with r-EPO. In addition, our results indicate that STR, HFR and HE may provide useful information for the clinical management of these patients.     

Serum erythropoietin in chronic lymphocytic leukaemia

OBJECTIVE: To establish whether there is any improvement in pregnancy and implantation rates after administration of "low-dose," long-acting glucocorticoids during transfer of cryopreserved-thawed embryos. SETTING: An IVF unit in a university hospital. DESIGN: Prospective, randomized study. Ninety-nine consecutive transfer cycles of frozen-thawed embryos to the uterine cavity of randomly chosen women diagnosed as having tubal factor infertility only. Fifty-two patients underwent transfer of frozen-thawed embryos and received 0.5 mg of dexamethasone; 47 women (control group) did not receive the drug during transfer. PATIENTS: Normal ovulatory patients with tubal factor infertility. INTERVENTIONS: Oral dexamethasone administration before, during and after transfer of thawed embryos. MAIN OUTCOME MEASURES: Pregnancy and implantation rates. RESULTS: The pregnancy rate was 13.5% (7/52) in patients treated with the "low-dose" regimen of dexamethasone compared with 12.8% (6/47) in the control group. The implantation rate was similar. CONCLUSION: Our results demonstrated that the use of 0.5 mg dexamethasone for an immuno-suppressive effect, administered for a short period to patients diagnosed as having "pure" tubal factor infertility, did not improve the implantation or pregnancy rates.     

Tissue distribution of erythropoietin and erythropoietin receptor in the developing human fetus

The purpose of this exploratory study was to describe a group of African American women who smoke crack. Using aggregate data from 208 interviews with women crack smokers, we randomly selected 25 women's interview data to create the 25 life-lines. These life-lines were developed in a similar manner to the time-line analysis described by Fullilove and her colleagues (1992); we focused on events that are either extraordinarily disturbing (e.g., rape, incest, death of a child, etc.), events that are usual but often stressful (e.g., birth of a child, death of a parent, etc.), and on periods of drug use. We chose this method of analysis so as to highlight the context in which many women come to use crack cocaine. The life-lines provided a retrospective (but time-ordered) perspective and in several ways provided preliminary support for a stress-diathesis perspective.     

Is serum transferrin receptor useful for detecting iron-deficiency in anaemic patients with chronic inflammatory diseases?

We investigated whether determination of serum transferrin receptor (TfR) is useful for detecting iron-deficiency in patients with chronic inflammatory diseases and for differentiating between iron-deficiency anaemia and anaemia of inflammation. Using an immunofluorometric assay, serum TfR was measured in 34 anaemic patients. Of these patients, 23 had a chronic rheumatic disease, 13 with both inflammation and iron-deficiency and 10 with anaemia of inflammation only; the other 11 patients had iron-deficiency anaemia and no evidence of inflammation. Serum TfR concentrations were lower in patients with anaemia of inflammation (2.6 +/- 0.2 mg/l, mean +/- S.E.M.) than in patients with iron-deficiency anaemia (6.7 +/- 1.1 mg/l, P < 0.01) or those with both inflammation and iron deficiency (5.8 +/- 1.0 mg/l, P < 0.01). Among patients with inflammatory disease, correlations between TfR and ferritin concentrations (r = -0.62, P < 0.05) and TfR and erythropoietin concentrations (r = 0.69, P < 0.001) were observed in iron-deficient subjects only. TfR, though not superior to serum ferritin, can help to distinguish between anaemia of inflammation and iron-deficiency anaemia and to identify iron-deficiency in subjects with chronic inflammation.     

Serum erythropoietin and granulocyte-macrophage-colony stimulating factor levels with megadose methylprednisolone treatment

We described an anesthetic management of a patient with abdominal aortic aneurysm associated with dilated cardiomyopathy (DCM) focusing on preanesthetic evaluation of cardiovascular reserve and on intraoperative continuous circulatory monitoring with transesophageal echocardiography (TEE) and continuous cardiac output measurement (CCO). Based on echocardiographic and hemodynamic measurements after a 50 m-walk load, we predicted the allowable range of alteration of preload (LV diastolic dimension; Dd), myocardial performance (arterial blood pressure and ejection fraction) and of heart rate. During anesthesia and operation, we continuously monitored Dd, arterial blood pressure, heart rate and cardiac output, and maintained these variables within the allowable range. The changes in preload after clamping or unclamping of the aorta was promptly reflected by Dd as compared to pulmonary capillary wadge pressure. The CCO was also usuful in detecting abrupt changes in myocardial performance. In conclusion, we suggest preanesthetic stress test to be performed to evaluate cardiovascular reserve and to predict the allowable range of alteration of hemodynamic variables. Continuous monitoring of preload (Dd) by TEE and of myocardial performance by CCO is useful to detect early changes in these variables.     

Urokinase receptor genotypes in colorectal cancer

A previous study has reported a high frequency of rare alleles of the urokinase-type plasminogen activator receptor (uPAR) in a set of 15 colorectal cancer (CRC) cell lines. Our study investigated uPAR gene variation in 92 CRC patients and in tumour DNA from a subset of 69 patients using the PLAUR-IVS3 marker located in an intron of this gene. The overall distribution of the marker alleles in the patients did not differ significantly from a set of 105 controls. A pairwise analysis of individual allele frequencies showed, however, that the common allele 147 was significantly decreased (P = 0.027) and allele 149 was significantly increased (P = 0.033) in the patients. These results may indicate an effect of uPAR gene variation in CRC carcinogenesis and encourages further examination of this marker in an independent series of patients.     

Selenium and vitamin E deficiency impair transferrin receptor internalization but not IL-2, IL-2 receptor, or transferrin receptor expression

The amelogenin genes encode abundant enamel proteins that are required for the development of normal tooth enamel. These genes are active only in enamel-forming ameloblasts within the dental organ of the developing tooth, and are part of a small group of genes that are active on both sex chromosomes. The upstream regions of the bovine X- and Y-chromosomal and the sole murine X-chromosomal amelogenin genes have been cloned and sequenced, and conservation at nearly 60% is found in the 300 bp upstream of exon 1 for the 3 genes. A region of the bovine X-chromosomal gene that has inhibitory activity when assayed by gene transfer into heterologous cells includes motifs that have a silencing activity in other genes, and may be important to the mechanism that represses amelogenin expression in non-ameloblast cells in vivo. A comparison of sequences from three genes has led to the identification of several regions with conserved motifs that are strong candidates for having positive or negative regulatory functions, and these regions can now be tested further for interaction with nuclear proteins, and for their ability to regulate expression in vivo.