Mitochondrial dysregulation and oxidative stress in patients with chronic kidney disease

Several reports have focused on the identification of biological elements involved in the development of abnormal systemic biochemical alterations in chronic kidney disease, but this abundant literature results most of the time fragmented. To better define the cellular machinery associated to this condition, we employed an innovative high-throughput approach based on a whole transcriptomic analysis and classical biomolecular methodologies. The genomic screening of peripheral blood mononuclear cells revealed that 44 genes were up-regulated in both chronic kidney disease patients in conservative treatment (CKD, n=9) and hemodialysis (HD, n=17) compared to healthy subjects (NORM) (p<0.001, FDR=1%). Functional analysis demonstrated that 11/44 genes were involved in the oxidative phosphorylation system (OXPHOS). Western blotting for COXI and COXIV, key constituents of the complex IV of OXPHOS, performed on an independent testing-group (12 NORM, 10 CKD and 14 HD) confirmed the elevated synthesis of these subunits in CKD/HD patients. However, complex IV activity was significantly reduced in CKD/HD patients compared to NORM (p<0.01). Finally, CKD/HD patients presented higher reactive oxygen species and 8-hydroxydeoxyguanosine levels compared to NORM. Taken together these results suggest, for the first time, that CKD/HD patients may have an impaired mitochondrial respiratory system and this condition may be both the consequence and the cause of an enhanced oxidative stress.

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Granata S, Zaza G, Simone S, Villani G, Latorre D, Pontrelli P, Carella M, Schena FP, Grandaliano G, Pertosa G