Influence de l'hémodialyse sur les concentrations de malonedialdéhyde total et libre, mesurées par une nouvelle technique HPLC spécifique

Assessment of hemodialysis impact by Polysulfone membrane on brain plasticity using BOLD-fMRI

PURPOSE

Hemodialysis (HD) is considered the most common alternative for overcoming renal failure. Studies have shown the involvement of HD membrane in the genesis of oxidative stress (OS) which has a direct impact on the brain tissue and is expected to be involved in brain plasticity and also reorganization of brain function control. The goal of this paper was to demonstrate the sensitivity of the blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) to characterize the OS before and after the HD session.

PATIENTS, MATERIALS AND METHODS

Twelve male patient-volunteers following chronic HD for more than 6months were recruited among 86 HD-patients. All patients underwent identical assessment immediately before and after the full HD-session. This consisted of full biological assessment, including malondialdehyde (MDA) and total antioxidant activity (TAOA); and brain BOLD-fMRI using the motor paradigm in block-design.

RESULTS

Functional BOLD-fMRI maps of motor area M1 were obtained from the HD patient before and after the hemodialysis session, important decrease in the intensity of brain activation of the motor area after HD, and important increase of the size of the volume of brain activation were observed, these changes are reflecting brain plasticity that is well correlated to OS levels. Individual patients MDA and TAOA before and after the hemodialysis sessions demonstrated a clear and systematic increase of the OS after HD (P-value=0.03). Correlation of BOLD-fMRI maximal signal intensity and volume of activated cortical brain area behaviors to MDA and total TAOA were close to 1.

CONCLUSION

OS is systematically increased in HD-patients after the HD-process. Indeed, the BOLD-fMRI shows a remarkable sensitivity to brain plasticity studied cortical areas. Our results confirm the superiority of the BOLD-fMRI quantities compared to the biological method used for assessing the OS while not being specific, and reflect the increase in OS generated by the HD. BOLD-fMRI is expected to be a suitable tool for evaluating the plasticity process evolution in hemodialysis brain patients.

[Plasma malondialdehyde may not predict mortality in patient with chronic kidney disease]

The role of oxidative stress in patients with chronic kidney disease (CKD) as a potential marker of morbidity and mortality remains poorly evaluated. The aim of the present study aims was thus: to determine plasma levels of malondialdehyde (MDA), end product of lipid peroxidation in patients at different CKD stages (predialysis and dialysis); to evaluate the association between plasma MDA levels and vascular disease or overall and cardiovascular mortality. Plasma MDA levels evaluated by HPLC, pulse wave velocity, aortic calcification score were evaluated in 94 CKD patients (67±13 years, 54% males, 29% at CKD stages 2-3, 32% at stages 4-5, 39% at stage 5D) prospectively followed for mortality. We observed that the plasma MDA levels were increased in patient with CKD and augmented progressively with CKD stages. However, we did not find any independent association between plasma levels of MDA and pulse wave velocity, aortic calcification score, or overall and cardiovascular mortality. Our results suggest that plasma MDA is not a useful biomarker in CKD patients.