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Iron as the key modulator of hepcidin expression in erythroid antibody-mediated hypoplasia.

Fernandes JC, Garrido P, Ribeiro S, Rocha-Pereira P, Bronze-da-Rocha E, Belo L, Costa E, Reis F, Santos-Silva A - Biomed Res Int (2014)

Bottom Line: Endogenous EPO levels were normal, suggesting that anti-rHuEPO antibodies blunted EPO function.Our results suggest that anti-rHuEPO antibodies inhibit erythropoiesis causing anemia.These findings might contribute to improving new therapeutic strategies against rHuEPO resistance and/or development of antibody-mediated EH in patients under rHuEPO therapy.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Pharmacology and Experimental Therapeutics, IBILI, Faculty of Medicine, University of Coimbra, . 3000-548 Coimbra, Portugal ; Institute for Molecular and Cellular Biology, University of Porto, 4150-180 Porto, Portugal.

ABSTRACT
Erythroid hypoplasia (EH) is a rare complication associated with recombinant human erythropoietin (rHuEPO) therapies, due to development of anti-rHuEPO antibodies; however, the underlying mechanisms remain poorly clarified. Our aim was to manage a rat model of antibody-mediated EH induced by rHuEPO and study the impact on iron metabolism and erythropoiesis. Wistar rats treated during 9 weeks with a high rHuEPO dose (200 IU) developed EH, as shown by anemia, reduced erythroblasts, reticulocytopenia, and plasmatic anti-rHuEPO antibodies. Serum iron was increased and associated with mRNA overexpression of hepatic hepcidin and other iron regulatory mediators and downregulation of matriptase-2; overexpression of divalent metal transporter 1 and ferroportin was observed in duodenum and liver. Decreased EPO expression was observed in kidney and liver, while EPO receptor was overexpressed in liver. Endogenous EPO levels were normal, suggesting that anti-rHuEPO antibodies blunted EPO function. Our results suggest that anti-rHuEPO antibodies inhibit erythropoiesis causing anemia. This leads to a serum iron increase, which seems to stimulate hepcidin expression despite no evidence of inflammation, thus suggesting iron as the key modulator of hepcidin synthesis. These findings might contribute to improving new therapeutic strategies against rHuEPO resistance and/or development of antibody-mediated EH in patients under rHuEPO therapy.

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Relative mRNA expression of erythropoietin and iron regulatory proteins in the liver, at the end of the protocol (9 weeks). 18S rRNA was used as reference gene. Results are expressed as mean ± SD. *P < 0.05, **P < 0.01, and ***P < 0.001 versus control group; #P < 0.05, ##P < 0.01, and ###P < 0.001 versus 50 IU rHuEPO.
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fig3: Relative mRNA expression of erythropoietin and iron regulatory proteins in the liver, at the end of the protocol (9 weeks). 18S rRNA was used as reference gene. Results are expressed as mean ± SD. *P < 0.05, **P < 0.01, and ***P < 0.001 versus control group; #P < 0.05, ##P < 0.01, and ###P < 0.001 versus 50 IU rHuEPO.

Mentions: Major changes were observed in the gene expression of iron regulatory proteins and in erythropoietic regulatory proteins in liver tissue (Figure 3), particularly in the 200 IU rHuEPO group. Indeed, the 50 IU rHuEPO group showed significant overexpression of HJV and SLC40A1 genes, as compared to control, while the 200 IU rHuEPO group presented significant overexpression of Hamp, Hfe, HJV, EPOR, SLC40A1, Tf, TfR2, and BMP6 genes, as compared to control and 50 IU rHuEPO group. EPO gene was significantly downregulated in both groups, and TMPRSS6 gene expression was significantly downregulated only in the 200 IU rHuEPO group, as compared to the control and 50 IU rHuEPO groups.


Iron as the key modulator of hepcidin expression in erythroid antibody-mediated hypoplasia.

Fernandes JC, Garrido P, Ribeiro S, Rocha-Pereira P, Bronze-da-Rocha E, Belo L, Costa E, Reis F, Santos-Silva A - Biomed Res Int (2014)

Relative mRNA expression of erythropoietin and iron regulatory proteins in the liver, at the end of the protocol (9 weeks). 18S rRNA was used as reference gene. Results are expressed as mean ± SD. *P < 0.05, **P < 0.01, and ***P < 0.001 versus control group; #P < 0.05, ##P < 0.01, and ###P < 0.001 versus 50 IU rHuEPO.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4281449&req=5

fig3: Relative mRNA expression of erythropoietin and iron regulatory proteins in the liver, at the end of the protocol (9 weeks). 18S rRNA was used as reference gene. Results are expressed as mean ± SD. *P < 0.05, **P < 0.01, and ***P < 0.001 versus control group; #P < 0.05, ##P < 0.01, and ###P < 0.001 versus 50 IU rHuEPO.
Mentions: Major changes were observed in the gene expression of iron regulatory proteins and in erythropoietic regulatory proteins in liver tissue (Figure 3), particularly in the 200 IU rHuEPO group. Indeed, the 50 IU rHuEPO group showed significant overexpression of HJV and SLC40A1 genes, as compared to control, while the 200 IU rHuEPO group presented significant overexpression of Hamp, Hfe, HJV, EPOR, SLC40A1, Tf, TfR2, and BMP6 genes, as compared to control and 50 IU rHuEPO group. EPO gene was significantly downregulated in both groups, and TMPRSS6 gene expression was significantly downregulated only in the 200 IU rHuEPO group, as compared to the control and 50 IU rHuEPO groups.

Bottom Line: Endogenous EPO levels were normal, suggesting that anti-rHuEPO antibodies blunted EPO function.Our results suggest that anti-rHuEPO antibodies inhibit erythropoiesis causing anemia.These findings might contribute to improving new therapeutic strategies against rHuEPO resistance and/or development of antibody-mediated EH in patients under rHuEPO therapy.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Pharmacology and Experimental Therapeutics, IBILI, Faculty of Medicine, University of Coimbra, . 3000-548 Coimbra, Portugal ; Institute for Molecular and Cellular Biology, University of Porto, 4150-180 Porto, Portugal.

ABSTRACT
Erythroid hypoplasia (EH) is a rare complication associated with recombinant human erythropoietin (rHuEPO) therapies, due to development of anti-rHuEPO antibodies; however, the underlying mechanisms remain poorly clarified. Our aim was to manage a rat model of antibody-mediated EH induced by rHuEPO and study the impact on iron metabolism and erythropoiesis. Wistar rats treated during 9 weeks with a high rHuEPO dose (200 IU) developed EH, as shown by anemia, reduced erythroblasts, reticulocytopenia, and plasmatic anti-rHuEPO antibodies. Serum iron was increased and associated with mRNA overexpression of hepatic hepcidin and other iron regulatory mediators and downregulation of matriptase-2; overexpression of divalent metal transporter 1 and ferroportin was observed in duodenum and liver. Decreased EPO expression was observed in kidney and liver, while EPO receptor was overexpressed in liver. Endogenous EPO levels were normal, suggesting that anti-rHuEPO antibodies blunted EPO function. Our results suggest that anti-rHuEPO antibodies inhibit erythropoiesis causing anemia. This leads to a serum iron increase, which seems to stimulate hepcidin expression despite no evidence of inflammation, thus suggesting iron as the key modulator of hepcidin synthesis. These findings might contribute to improving new therapeutic strategies against rHuEPO resistance and/or development of antibody-mediated EH in patients under rHuEPO therapy.

Show MeSH
Related in: MedlinePlus