Research Viewpoints Tissue [Na+] in Patients with Kidney Failure: Association with Cardiovascular Disease

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Friedrich A.C, Linz P, Nagel A, Rosenhauer D, Horn S, Schiffer M, Uder M, Kopp C, Dahlmann A: Hemodialysis Patients with Cardiovascular Disease Reveal Increased Tissue Na+ Deposition. Kidney and Blood Pressure Research DOI 10.1159/520821

Sodium balance in patients with kidney failure treated by dialysis is highly variable and incompletely understood, in pathophysiological terms. Sodium excess is linked both to hypertension and cardiovascular disease (CVD), particularly heart failure. Some of the excess sodium retained in CKD is stored in skin (and muscle), non-osmotically. The role of this storage of retained sodium in the pathogenesis of CVD remains uncertain.

Friedrich and colleagues examined this issue in an observational study of hemodialysis patients with (n=23) and without (n=29) overt CVD. ²³Na- MRI at 3.0 Tesla was used to quantify the sodium content of skin and muscle before and after a dialysis treatment session. Body fluid distribution parameters were examined by bioimpedance spectroscopy.

Skin and muscle sodium content was increased in those with overt CVD, bur extracellular water levels were similar in both groups. Those patients with high skin or muscle sodium content had higher levels of inflammatory markers (Il-6) than those without such increased levels of sodium in skin or muscle. The causal pathways responsible for these associations could not be determined due to the study design, but the findings support the hypothesis that skin/muscle (non-osmotic) storage of sodium in CKD is somehow involved in the pathogenesis of CVD.