title: Iron-hepcidin dysmetabolism, anemia and renal hypoxia, inflammation and fibrosis in the remnant kidney rat model.
abstract: Anemia is a common complication of chronic kidney disease (CKD) that develops early and its severity increases as renal function declines. It is mainly due to a reduced production of erythropoietin (EPO) by the kidneys; however, there are evidences that iron metabolism disturbances increase as CKD progresses. Our aim was to study the mechanisms underlying the development of anemia of CKD, as well as renal damage, in the remnant kidney rat model of CKD induced by 5/6 nephrectomy. This model of CKD presented a sustained degree of renal dysfunction, with mild and advanced glomerular and tubulointerstitial lesions. Anemia developed 3 weeks after nephrectomy and persisted throughout the protocol. The remnant kidney was still able to produce EPO and the liver showed an increased EPO gene expression. In spite of the increased EPO blood levels, anemia persisted and was linked to low serum iron and transferrin levels, while serum interleukin (IL)-6 and high sensitivity C-reactive protein (hs-CRP) levels showed the absence of systemic inflammation. The increased expression of duodenal ferroportin favours iron absorption; however, serum iron is reduced which might be due to iron leakage through advanced kidney lesions, as showed by tubular iron accumulation. Our data suggest that the persistence of anemia may result from disturbances in iron metabolism and by an altered activity/function of EPO as a result of kidney cell damage and a local inflammatory milieu, as showed by the increased gene expression of different inflammatory proteins in the remnant kidney. In addition, this anemia and the associated kidney hypoxia favour the development of fibrosis, angiogenesis and inflammation that may underlie a resistance to EPO stimuli and reduced iron availability. These findings might contribute to open new windows to identify putative therapeutic targets for this condition, as well as for recombinant human EPO (rHuEPO) resistance, which occurs in a considerable percentage of CKD patients.
authors: Laboratory of Pharmacology & Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Center for Neuroscience and Cell Biology-Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Unit, University of Coimbra, Coimbra, Portugal.
authors: Patrícia
authors: P
authors: Garrido
authors: Research Unit on Applied Molecular Biosciences (UCIBIO), REQUIMTE, Department of Biological Sciences, Laboratory of Biochemistry, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors: Sandra
authors: S
authors: Ribeiro
authors: Laboratory of Pharmacology & Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Center for Neuroscience and Cell Biology-Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Unit, University of Coimbra, Coimbra, Portugal.
authors: João
authors: J
authors: Fernandes
authors: Center for Studies in Education, Technologies and Health (CI&DETS), Agrarian School of Viseu, Polytechnic Institute of Viseu, Viseu, Portugal.
authors: Helena
authors: H
authors: Vala
authors: Research Unit on Applied Molecular Biosciences (UCIBIO), REQUIMTE, Department of Biological Sciences, Laboratory of Biochemistry, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors: Elsa
authors: E
authors: Bronze-da-Rocha
authors: Research Centre in Health Sciences, University of Beira Interior, Covilhã, Portugal.
authors: Petronila
authors: P
authors: Rocha-Pereira
authors: Research Unit on Applied Molecular Biosciences (UCIBIO), REQUIMTE, Department of Biological Sciences, Laboratory of Biochemistry, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors: Luís
authors: L
authors: Belo
authors: Research Unit on Applied Molecular Biosciences (UCIBIO), REQUIMTE, Department of Biological Sciences, Laboratory of Biochemistry, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors: Elísio
authors: E
authors: Costa
authors: Research Unit on Applied Molecular Biosciences (UCIBIO), REQUIMTE, Department of Biological Sciences, Laboratory of Biochemistry, Faculty of Pharmacy, University of Porto, Porto, Portugal.
authors: Alice
authors: A
authors: Santos-Silva
authors: Laboratory of Pharmacology & Experimental Therapeutics, Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Center for Neuroscience and Cell Biology-Institute for Biomedical Imaging and Life Sciences (CNC.IBILI) Research Unit, University of Coimbra, Coimbra, Portugal.
authors: Flávio
authors: F
authors: Reis
mesh_terms: D000740:Anemia / Q000378:metabolism*; D000818:Animals; D001794:Blood Pressure; D001835:Body Weight; D004195:Disease Models, Animal; D004921:Erythropoietin / Q000097:blood / Q000378:metabolism; D005355:Fibrosis / Q000378:metabolism; D064451:Hepcidins / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism* / Q000601:surgery; D008099:Liver / Q000378:metabolism; D008297:Male; D009929:Organ Size; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D017467:Receptors, Erythropoietin / Q000235:genetics
chemical_list: D064451:Hepcidins; D012333:RNA, Messenger; D017467:Receptors, Erythropoietin; D004921:Erythropoietin; D007501:Iron