title: The continuous erythropoietin receptor activator affects different pathways of diabetic renal injury.
abstract: This study explored the tissue-protective properties of the continuous erythropoietin receptor activator (CERA) in an experimental model of (nonischemic) diabetic kidney injury (i.e., the db/db mouse). Mice were randomly treated with placebo (n = 25), low-dosage CERA (n = 25), and high-dosage CERA (n = 25). Also studied were 25 nondiabetic db/m mice. Hematocrit was comparable in placebo and low-dosage CERA-treated mice but increased significantly with high-dosage CERA (P < 0.01 versus both). Significantly reduced expression of TGF-beta, vascular endothelial growth factor, and collagen IV was found in glomeruli and the tubulointerstitial area with CERA treatment, and these beneficial molecular effects were clearly dosage dependent (both P < 0.05 versus placebo). Similarly, CERA treatment caused a dosage-dependent increase in p-Akt, nephrin, and perlecan tissue expression (all P < 0.05 versus placebo). However, the accelerated mesangial expansion that was observed in placebo-treated db/db mice (versus db/m controls) was significantly reduced only in low-dosage CERA-treated mice (P < 0.01). Moreover, albuminuria was significantly reduced in low- but not high-dosage CERA-treated mice compared with placebo treatment (P < 0.05). In an ancillary study, phlebotomy was performed in high-dosage CERA-treated db/db mice to keep hematocrit within normal (baseline) levels. This procedure resulted in significantly (P < 0.05) less albuminuria as compared with high-dosage CERA-treated mice without phlebotomy, thus preserving the tissue-protective potential of CERA. Long-term CERA treatment has beneficial dosage-dependent effects on molecular pathways of diabetic kidney damage. Low-dosage CERA does not affect hematocrit and therefore may be a feasible method of tissue protection in this setting.
authors.affiliation: Department of Internal Medicine, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Menne
authors.forename: Joon-Keun
authors.initials: JK
authors.lastname: Park
authors.forename: Nelli
authors.initials: N
authors.lastname: Shushakova
authors.forename: Michael
authors.initials: M
authors.lastname: Mengel
authors.forename: Matthias
authors.initials: M
authors.lastname: Meier
authors.forename: Danilo
authors.initials: D
authors.lastname: Fliser
mesh_terms: D000818:Animals; D003928:Diabetic Nephropathies / Q000378:metabolism* / Q000473:pathology; D004921:Erythropoietin / Q000502:physiology*; D007150:Immunohistochemistry; D007668:Kidney / Q000473:pathology; D051379:Mice; D011092:Polyethylene Glycols; D011994:Recombinant Proteins
chemical_list: D011994:Recombinant Proteins; C508420:continuous erythropoietin receptor activator; D004921:Erythropoietin; D011092:Polyethylene Glycols