Oxidative stress and other risk factors for white matter lesions in chronic hemodialysis patients

Chronic kidney disease (CKD) is a risk factor for cardiovascular disease and promotes oxidative tress (OS), which has been implicated in the pathogenesis of white matter lesions (WML), a form of small-vessel cerebrovascular disease. The relationship between OS and WML in chronic hemodialysis (HD) patients has not yet been studied.

We studied 67 chronic HD patients, aged 40 - 65 years (average 54 years) without known cerebrovascular disease. All patients underwent brain magnetic resonance imaging and subcortical and periventricular WML were evaluated using semiquantitative measures. Patients were classified into two groups depending on the presence or absence of WML (Fazekas classification), and the WML were scored. Carotid ultrasonography was also performed to evaluate the presence of carotid artery plaques and/or stenosis. Markers of protein and lipid oxidation (protein carbonyl and oxLDL antibodies), the glutathione system, enzymatic antioxidants (superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase) and total antioxidant capacity (ORAC) were measured. OS markers were compared to those of a group of 36 healthy subjects.

WML were present in 54% of the total population. Patients who had WML were older and had lower predialysis diastolic blood pressure than patients without WML. Other potential cardiovascular risk factors for WML, including obesity, hyperlipidemia, diabetes mellitus, presence of carotid artery plaques or stenosis, and duration and adequacy of HD were not related to the presence of WML. Compared to controls, HD patients had increased OS and decreased antioxidant capacity. However, OS did not differ between patients with WML and those without, and we found no association between OS markers and mean WML scores. After adjusting for several factors, only age and low predialysis diastolic blood pressure independently predicted an increased risk of WML.

Our results confirm that chronic HD patients have increased OS, but this is not related to the presence or severity of WML.