Soluble transferrin receptor and soluble transferrin. Soluble transferrin receptor log ferritin tfrf index, using a cutoff of 5. New cutoff values for ferritin and soluble transferrin. After adding the product to the cart by clicking the button below you will see if there is a volume discount available. Transferrin receptor tfr expression is regulated by the iron regulatory protein system.
It is needed for the import of iron into the cell and is regulated in response to intracellular iron concentration. Tibc is increased in iron deficiency, pregnancy and by oral contraceptive therapy. The function of the single olinked oligosaccharide near the transmembrane domain of the tfr at amino acid thr 104 is unknown. Tfr is a homodimeric membrane glycoprotein that binds two molecules of tf. Levels of this receptor are increased in irondeficiency anemia.
The serum concentration of stfr reflects the amount of the cellular receptor 1,2. Tfr transferrin r the transferrin receptor tfr or tfr1, designated cd71 is a type 2 transmembrane glycoprotein expressed on erythroid progenitors, muscle cells and proliferating cells as a 188 kda disulfidelinked homodimer of 95 kda monomers 1 4. However, researchers have been able to identify the dominating role of the transferrin transferrin receptor complex in the internalization of iron. Human transferrin receptor elisa kit ab217780 is a singlewash 90 min sandwich elisa designed for the quantitative measurement of transferrin receptor protein in cit plasma, edta plasma, hep plasma, saliva, serum, urine, and cell culture extracts. Total iron binding capacity is a measure of the total amount of iron with which plasma can combine.
The soluble transferrin receptor stfr has an important role in the regulation of iron by mediating the cellular uptake of transferrin bound iron 2. Soluble transferrin receptor is elevated in association with hyperplastic erythropoiesis, for example, in patients with haemolytic anaemia or betathalassaemia. It consists of two identical subunits linked by disulfide bridges. The circulating stfr concentration is proportional to cellular expression of the membraneassociated tfr and increases with increased cellular iron needs and cellular proliferation.
The usefulness of soluble transferrin receptor stfr in differentiating anemia occurring in young children article pdf available in folia histochemica et cytobiologica 503. Thus, an efficient sample pretreatment strategy is required. Soluble transferrin receptors are proteins found in blood that can be elevated with iron deficiency. Use of soluble transferrin receptor tfr for the diagnosis of iron deficiency anemia ida in cirrhotic patients. The soluble transferrin receptor stfr is a soluble truncated form of the transferrin receptor. Soluble transferrin receptor stfr is a new marker of iron status and erythropoietic activity. Effects of exercise on soluble transferrin receptor and. Role of soluble transferrin receptor and transferrin. Transferrin receptor an overview sciencedirect topics. Elevated soluble transferrin receptor stfr in a patient. Tfr is a transmembrane, disulfidelinked dimer of two identical subunits that binds and internalizes diferric transferrin, thereby delivering iron to the cell cytosol. The transferrin receptor tfr is a homodimeric type ii membrane protein that mediates iron uptake into the cells.
As the tfrtransferriniron complex reaches the cell membrane it is internalized via an endocytic vesicle. Production of the soluble portion of the transferrin receptor stfr by baby hamster kidney bhk cells is described, and the effect of glycosylation on the biological function of stfr is evaluated for the first time. This test measures the amount of soluble transferrin receptors within the blood, to help detect and evaluate iron deficiency and aid in the diagnosis of iron deficiency anaemia iron is an essential nutrient absorbed from the diet. Endocytosed tftfr is diverged from lysosometargeted proteins in ee with a t. The stfr median concentrations in our population decreased gradually from the group aged 310 years to the group aged 2140. The existence of a receptor for transferrin iron uptake had been recognized over half a century back. No study has investigated the meaning of high stfr as the only positive marker of iron deficiency anemia ida caused by gastrointestinal tract git bleeding in hospitalized patients. To combine data, individual survey analyses, which accounted for. The best diagnostic parameter for detecting iron deficiency in patients with malignant hemopathies by roc analysis is the soluble transferrin receptor log ferritin index auc 0.
Recent investigations have demonstrated that the soluble form of the transferrin receptor in human serum is an 85kda fragment of intact receptor containing most of the extracellular domain. Soluble transferrin receptor conventionally refers to the cleaved extracellular portion of. The cohort was randomly divided into exploratory n 200 and validation sets n 628. In the intracellular compartment, iron dissociates from tfrtransferrin complex. Efficient molecular imprinting strategy for quantitative. Transferrin has two ironbinding sites and is largely, but not exclusively, synthesized by the liver. Concentrations of serum stfr are related to iron status and erythropoiesis in the body. Several iron indicators can be used to detect iron deficiency anaemia ida where confounding comorbidities occurred such as patients with regular hemodialysis. Soluble transferrin receptor an overview sciencedirect topics. This study aim was to determine the diagnostic value of stfr and tfrf index and to combine these two markers in detecting ida in rh anaemic. This receptor is a protein dimer of two identical subunits, linked together by two pairs of disulfide bonds. Serum concentrations of the stfr increase in iron deficiency when there is inadequate iron delivery to the bone marrow and tissues.
Serum stfr levels are determined to detect iron deficiency. It may be ordered as an alternative to ferritin when you have a chronic illness andor inflammation is present or suspected. Transferrin receptor is a 760 amino acid, transmembrane glycoprotein composed of two disulfidelinked monomers encoded by the gene tfrc. Soluble transferrin receptor stfr is a truncated extracellular form of the membrane transferrin receptor produced by proteolysis. Targetspecific elisa kits are available from a variety of manufacturers and can help streamline your immunodetection experiments. Moreover, there is a paucity of data on pediatric reference intervals for stfr and stfrferritin index. Soluble transferrin receptor conventionally refers to the cleaved extracellular portion of transferrin receptor 1 that is released into serum. In order to improve the diagnostic accuracy of ferritin or stfr as a standalone marker, the normal cutoff value needed to be increased by 810% and 83%. Soluble transferrin receptor as a diagnostic laboratory test. Nov 26, 2001 abstract the aim of this study was to establish soluble serum transferrin receptor stfr reference limits.
The usefulness of soluble transferrin receptor in the. Pdf the usefulness of soluble transferrin receptor stfr. In this study wemeasured stfr levels in the cases of betathalassemia trait. In this context the multifunctional glycolytic enzyme glyceraldehyde3phosphate dehydrogenase gapdh has been reported as a soluble receptor for transferrin. Soluble transferrin receptor stfr in serum has been suggested as a marker for breast cancer diagnosis, monitoring and treatment. It is widely used in mammalian cell cultures for the production of biotherapeutic proteins and vaccines and is also being explored for use as a therapy and targeted.
Soluble transferrin receptor and risk of type 2 diabetes. Tfr is an essential receptor, found on almost all cell types, regulated by intracellular iron concentration, and has a high affiinity for transferrin. Serum gel tubes should be centrifuged within 2 hours of collection. The significance of soluble transferrin receptors in.
Transferrin receptor testing is used to measure the level of soluble transferrin receptors, thereby aiding in the evaluation of iron deficiency and in the diagnosis of irondeficiency anemia the reference range of transferrin receptor varies by sex in adults, as follows. Adjusting soluble transferrin receptor concentrations for. Effect of glycosylation on the function of a soluble. Soluble transferrin receptor stfr is a circulating, cleaved form of a membrane receptor protein. Because serum ferritin is an acutephase reactant and because the inflammatory state may inhibit the mobilization of iron from reticuloendothelial stores, the scenario of. Parameters for measuring iron deficiency have been established for decades and have served clinicians in the management of this nutritional disorder. The bone marrow still remains the gold standard in the final diagnosis of iron deficiency.
An early idea was to combine the assay of serum ferritin with a measure of. Iron is released from transferrin as the result of the acidic ph in endosome and then is transported to the cytosol by dmt1. Serum transferrin is an independent predictor of mortality. Tt and ida to see whether it would be a diagnostic tool for the differentiation of. Soluble transferrin receptors stfr are proteins found in blood that can become elevated in the presence of irondeficiency. A majority of plasma transferrin receptors are derived from the erythroid marrow, and their concentration is determined primarily by erythroid marrow activity. Soluble transferrin receptor elisa kits biocompare. The transferrin receptor is an integral membrane glycoprotein having a molecular weight of 190 kilodaltons kd. Tfr1 is a transmembrane glycoprotein composed of two disulfidelinked monomers joined by two disulfide bonds. In this study, molecularly imprinted polymers mips were developed and coupled with liquid.
Soluble transferrin receptor and erythrocyte protoporphyrin testing, or bone marrow biopsy can be considered if the diagnosis remains unclear. Soluble transferrin receptor an overview sciencedirect. Soluble transferrin receptor arises from proteolysis of the intact protein on the cell surface, leading to monomers that can be measured in plasma and serum. A major pathway for cellular iron uptake is through internalization of the complex of ironbound transferrin and the transferrin receptor, which is negatively modulated by hfe, a protein related to hereditary hemochromatosis. Soluble transferrin receptor stfr conversion to nmoll. Serum transferrin receptor levels for the assessment of iron status. Most of the binding capacity is due to transferrin. Proteolysis leads to the soluble form of the transferrin. We investigated whether serum stfr levels can aid in diagnosis and treatment of iron deficiency anemia ida in children. Transferrin is an ironbinding glycoprotein found in the.
However, stfr levels in some situations could be far below the limit of quantification loq of most assays. Soluble transferrin receptor, ferritin, iron deficiency. While decreased levels of circulating soluble transferrin receptor are found in patients with erythroid hypoplasia aplastic anemia, chronic renal failure. Soluble transferrin receptor stfr, one of the main regulators of cellular iron homeostasis, is the truncated form of the tissue receptor that is encoded by the human tfr gene chromosome 3. Tfr is abundant on the surface of many newly formed cells, but the erythroid marrow cells account for 70 to 80 % of the total body tfr content. Pdf background several iron indicators can be used to detect iron. Immunofluorescence analysis of transferrin receptor monoclonal antibody h68.
Each monomer binds one holo transferrin molecule creating an irontftfr complex which enters the cell by endocytosis. An increase in transferrin is seen in iron deficiency anemia. As the tfr transferrin iron complex reaches the cell membrane it is internalized via an endocytic vesicle. Human serum transferrin plays a critical physiological role in cellular iron delivery via the transferrin receptor mediated endocytosis pathway in nearly all eukaryotic organisms. Upon exposure to the acidic ph of the endosome, iron is. Thus, the concentration of stfr in plasma or serum is an indirect measure of total tfr. Transferrin receptors, which are blood proteins, may be elevated in persons with iron deficiency. Transferrin receptors are transmembrane, homodimeric proteins that play a role in iron transport, uptake, and storage.
Endocytosed transferrin receptors recycle via distinct. In plasma, the soluble transferrin receptor is present in the form of a complex with transferrin having a molecular weight of approximately 320 kd. This test measures the amount of soluble transferrin receptors to help detect and evaluate iron deficiency and aid in the diagnosis of iron deficiency anemia. A soluble receptor for any ligand could also refer to a molecule present is solution for example a secretory protein which would bind with the target ligand and then effect cellular delivery. Role of soluble transferrin receptor and transferrin receptor. The soluble transferrin receptor stfr has been introduced as a promising new diagnostic tool for differentiating between iron deficiency anemia ida and anemia of chronic disease acd. Increased levels of transferrin receptors tfr and soluble tfr stfr are reliable indicators of iron deficiency anemia and conditions with enhanced erythropoietic activity. The transferrin receptor is comprised of two identical subunits, each composed of 760 aminoacids with a molecular mass of 95 kdaltons. Interpreting indicators of iron status during an acute phase response. The soluble transferrin receptor test is not routine but may be ordered along with or in follow up to other iron tests when you have a normal or nearnormal ferritin level but iron deficiency is still suspected. Iron is an essential nutrient absorbed from the diet.
Transferrin levels rise with iron deficiency and fall in cases of iron overload. A study cohort of 436 apparently healthy children was analyzed to establish reference. Targeted drug delivery via the transferrin receptormediated. Abstract the aim of this study was to establish soluble serum transferrin receptor stfr reference limits. This test measures the amount of soluble transferrin receptors within the blood, to help detect and evaluate iron deficiency and aid in the diagnosis of iron deficiency anaemia.
Pdf use of soluble transferrin receptor tfr for the. Patients with sah had diminished serum transferrin but increased transferrin saturation. Pdf determination of serum soluble transferrin receptor stfr is proposed to distinguish between irondeficiency anemia and anemia of. Use of multiple antibiotics in patients with cf is routine. Measurement of circulating levels of the receptor are very useful in the diagnosis of iron deficiency in patients who also have anemia. Assayed interlaboratory controls for the assessment of precision and analytical bias on automated systems. Furthermore, stfr concentrations have been observed to be significantly higher in obese than in nonobese individuals. The increasing prevalence of multiple comorbidities among anemic patients with chronic kidney disease has made the use of serum ferritin and transferrin saturation more challenging in diagnosing iron deficiency. Transferrintransferrin receptormediated drug delivery li. In the intracellular compartment, iron dissociates from tfr transferrin complex. The tfrc gene encodes the transferrin receptor, which is important for cellular iron uptake. Tibc, transferrin saturation, soluble transferrin receptors. Transferrin receptor is a nonrtk constitutively recycling receptor and thus can be used as a control to assess rtk specificity of met trafficking.
Measurement of ferritin is used for the diagnosis of iron deficiency. Current cancer management strategies fail to adequately treat malignancies with multivariable doserestricting factors such as systemic toxicity and multidrug resistance limiting therapeutic benefit, quality of life and complete longterm remission rates. Soluble transferrin receptor and soluble transferrin recepterferritin index for evaluation of the iron status in elderly patients. Soluble transferrin receptor stfr had been suggested as an indicator for iron deficiency. Dec 01, 2002 the membrane transferrin receptor mediated endocytosis or internalization of the complex of transferrin bound iron and the transferrin receptor is the major route of cellular iron uptake. Proteolysis leads to the soluble form of the transferrin receptor stfr. Soluble transferrin receptor and ferritin concentrations were nephelometrically determined by n latex reagent sets bade behring according to the manufacturers instructions after storage of the centrifuged 2600g. Comparison of the interactions of transferrin receptor and. Serum transferrin receptor levels in betathalassemia. Soluble transferrin receptors and iron deficiency, a step. This study was aimed to determine the diagnostic value of serum transferrin receptor stfr and transferrin receptor transferrin index tfrf index and to combine these two markers in detecting ida in regular. Soluble transferrin receptor, human, in vitro, antibody cat.
Elimination of the olinked glycosylation site at thr 104. Circulating soluble transferrin receptor according to glucose. Studies evaluating the relationship between soluble transferrin receptor stfr, a biomarker inversely related to body iron stores, and risk of type 2 diabetes mellitus t2dm are scarce and inconclusive. Pdf soluble transferrin receptor stfr and stfrlog ferritin.
Soluble transferrin receptor definition of soluble. Epo, soluble transferrin receptor, hematocrit hct and % macrocytes were. Where exposure to inflammation is high, soluble transferrin receptor stfr. Pdf role of soluble transferrin receptor and transferrin. Recent studies have also suggested that stfr measurements are helpful when predicting the response to erythropoietin in patients with anaemia resultant from chronic renal failure. Recombinant soluble transferrin receptor rstfr1st who. Usually the soluble transferrin receptor values are also low. Tfr transferrin r the transferrin receptor tfr or tfr1, designated cd71 is a type 2 transmembrane glycoprotein expressed on erythroid progenitors, muscle cells and proliferating cells as a 188 kda disulfidelinked homodimer of 95 kda monomers 14.
Transferrin receptor tfr the transferrin receptor tfr is the gateway for transferrin boundiron entering all body cells. The targeted delivery of a therapeutic compound aims to enhance its circulation and cellular uptake, decrease systemic toxicity and improve. Soluble transferrin receptor stfr conversion to nmoll, mg. We aimed to study the contribution of the serum soluble transferrin receptor stfr. Is soluble transferrin receptor a good marker of iron. The cells were fixed with 4% paraformaldehyde for 10 minutes, permeabilized with 0. As transferrin expression increases with decrease in iron concentrations,measurementofitssoluble form can be a. Transferrin receptor tfr is a carrier protein for transferrin.
Soluble transferrin receptor article about soluble. The soluble transferrin receptor as a marker of iron homeostasis in normal subjects and in hferelated hemochromatosis article pdf available in haematologica 901. The transferrin receptor tfr is the plasma membrane protein responsible for the binding and internalization of the major iron transport protein, transferrin. Transferrin receptor tfr is the major mediator of iron uptake by cells. Although fully glycosylated stfr is secreted into the tissue culture medium. Transferrin and the blood brain barrier wed, 09072016 14. If ferritin levels do not rise and the symptoms are bothersome, intravenous iron might be.
Data from these patients were merged with those from the recently diagnosed type 2. Proteolysis leads to the soluble form of the transferrin receptor. Each of the monomers has an 85 kd cterminal component which can bind an ironladen transferrin molecule. Soluble transferrin receptor, human, in vitro, antibody. Human transferrin receptor elisa kit ab217780 abcam.
Soluble transferrin receptor levels may be helpful in distinguishing iron deficiency from anemia of chronic inflammation in cf because, unlike serum ferritin and transferrin, soluble transferrin receptor does not appear to be an acutephase reactant. The stfr median concentrations in our population decreased gradually from the group aged 310 years to the group. Development of a human soluble transferrin receptor elisa. Biological and clinical aspects of soluble transferrin. Tfr1 transferrin receptor 1 in human iron metabolism. The tfrcholotransferrin complex is internalized by receptor mediated endocytosis summary by jabara et al. The main sources of the stfr are the precursors of erythropoietic cells in the bone marrow. Also known as cd71 and tfr1, transferrin receptor is necessary to regulate iron transport into cells from transferrin by receptor mediated endocytosis. This efficient cellular uptake pathway has been exploited for the sitespecific delivery not only of anticancer drugs and proteins, but also of therapeutic genes into proliferating malignant cells that. Pdf the soluble transferrin receptor as a marker of iron. Recombinant soluble transferrin receptor rstfr 1st who reference reagent type of standard.
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