Association between selenium plasma levels and muscle function in hemodialysis patients

Selenium (Se) is a well-known antioxidant with a critical role in the proper functioning of nervous and muscle functions. In the last decade, many authors have suggested that Se may be a potent protective agent for neurons and myocytes through selenoprotein expression in the brain, as well as in skeletal and cardiac muscles. Low Se status has been associated with reduced coordination, motor speed and muscle strength. Reduced muscle function is common in hemodialysis (HD) patients; however, no study evaluated the association between muscle function and Se levels in HD patients. The objective of this study was to correlate muscle function with Se plasma levels in HD patients. Twenty HD patients (12 men, 54.5±15.2 yr; 81.7±52.8 months on HD) from RenalCor Clinic at Rio de Janeiro, Brazil were studied. Blood samples were collected during fasting, before a regular HD session. The Se plasma levels were determined by atomic absorption spectrophotometry with hydride generation (Hitachi, Z-500) and handgrip strength (HGS) was measured three times with a mechanical dynamometer (Jamar) after HD sessions in the non-fistula side and the highest value was used for analysis. HGS values less than the 10th percentile of an age-, gender- and regional specific reference were considered as muscle function loss. Plasma Se levels (31.9±14.8 μg/L) were below the normal range (60-120 μg/L) and all patients were Se deficient. HGS values were significantly greater in males (31.0±11.5 kg vs 14.0±6.8 kg for females) (p=0.001) and the muscle function loss was observed in 50% of patients and, those with muscle function loss presented low Se levels (26.5±12.1 μg/L) when compared to patients with preserved muscle function (39.12±14.5 μg/L) (p=0.05). These data suggest that Se can have an important role on muscle function in HD patients. However, more research is needed to better understand this possible relationship in CKD patients