Cytoprotection by darbepoetin/epoetin alfa in pig tubular and mouse mesangial cells.
BACKGROUND
Erythropoietin has recently been found to have cytoprotective effects in the central nervous system (CNS) and retina. The purpose of this study was to determine if darbepoetin alfa (DA) has cytoprotective properties in renal tissues.


METHODS
DA was studied in LLC/PK1 and mesangial cells. Renal cellular injury was induced in different experiments by prostaglandin D2 synthase (PGDS), camptothecin, hydrogen peroxide, and hypoxia. Cellular proliferation and apoptosis were measured [apoptosis by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end-labeling (TUNEL) assay or by caspase-3 activity]. In a separate experiment, an inactive form of erythropoietin alfa was used to study receptor effects.


RESULTS
DA protected against the antiproliferative effects of PGDS. In both LLC/PK1 (TUNEL and caspase-3) and mesangial cells (TUNEL), DA reduced the apoptotic stimulus of PGDS. Epoetin alfa was also found to reduce apoptosis. In LLC/PK1 cells, DA reduced apoptosis induced by camptothecin, but not hydrogen peroxide. DA reduced LLC/PK1 apoptosis induced by hypoxia when added 24 hours before hypoxia, but not when given concurrent with the hypoxic stimulus. Erythropoietin inactive did not protect against PGDS-induced apoptosis.


CONCLUSIONS
DA has renal antiapoptotic effects for both toxic and hypoxic stimuli. The effect may be mediated via the Erythropoietin receptor.
Fishbane
Steven
S
Winthrop-University Hospital, Division of Nephrology, Nephrology Laboratory, Mineola, New York 11501, USA. sfishbane@metrorenal.com
Ragolia
Louis
L
Palaia
Thomas
T
Johnson
Barbra
B
Elzein
Hafez
H
Maesaka
John K
JK
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002166:Camptothecin / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D015687:Cell Hypoxia / Q000187:drug effects; D000068256:Darbepoetin alfa; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004921:Erythropoietin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D005920:Glomerular Mesangium / Q000166:cytology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020287:In Situ Nick-End Labeling; D019746:Intramolecular Oxidoreductases / Q000494:pharmacology; D018374:LLC-PK1 Cells; D054834:Lipocalins; D051379:Mice; D016877:Oxidants / Q000494:pharmacology; D013552:Swine
D004791:Enzyme Inhibitors; D054834:Lipocalins; D016877:Oxidants; D004921:Erythropoietin; D000068256:Darbepoetin alfa; D006861:Hydrogen Peroxide; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D002166:Camptothecin