Xanthine oxidoreductase activity (XOR-a) plays an important role as a pivotal source of reactive oxygen species. In the present study, we investigated factors associated with plasma XOR-a in 163 hemodialysis patients (age 67.3 ± 10.9 years; 89 males and 74 females), using a newly established, highly-sensitive assay based on [13C2,15N2] xanthine and liquid chromatography/triple quadrupole mass spectrometry. Plasma glucose and serum uric acid levels correlated significantly and positively with plasma XOR-a. In multiple regression analyses, the presence of type 2 diabetes mellitus (T2DM) and plasma glucose were associated significantly, independently, and positively with plasma XOR-a. While serum uric acid correlated significantly and positively with plasma XOR-a in hemodialysis patients without T2DM, plasma glucose and serum glycated albumin, a new marker of glycemic control in diabetic hemodialysis patients, correlated significantly and positively with plasma XOR-a in those with T2DM. Multivariate analyses in those with T2DM revealed that plasma glucose and serum glycated albumin were associated significantly and independently with plasma XOR-a, and that serum uric acid was associated significantly and independently with XOR-a in those without T2DM. Our results suggested that glycemic control in hemodialysis patients may be important in regard to a decrease in ROS induced by XOR.

Objectives: To compare the effects of inpatient enhanced multidisciplinary care (EMC) and multidisciplinary rehabilitation (MR) on the symptoms and quality of life (QOL) of patients with Parkinson disease (PD) and to clarify the relation between reduction in symptoms and the improved QOL. Methods: This study was a quasi-randomized controlled (alternate allocation), assessor-blinded, single-center study. We recruited 80 patients with idiopathic Parkinson disease, Hoehn and Yahr stage 2 to 4, on stable medication. Patients were included in an EMC or MR group. Both rehabilitation programs were performed for 8 weeks (17 h/wk). Main outcome measures were Parkinson’s Disease Questionnaire-39 and Unified Parkinson’s Disease Rating Scale. Results: The EMC induced significant improvements in QOL compared to MR. We found that body axis symptoms (rising from a chair, posture, postural stability, falling, and walking) as well as nonmotor symptoms (depression) in patients with PD were relieved by the inpatient EMC. Conclusions: Enhanced multidisciplinary care for patients with PD appears to be effective in improving the QOL. The improvement in motor and nonmotor symptoms, including depression, may contribute to the improved QOL.

Oxidative stress plays a major role in development of cardiovascular disease in patients with chronic kidney disease (CKD). Human mercaptalbumin (HMA), a reduced form of serum albumin, and non-mercaptalbumin (HNA), an oxidized form of serum albumin, are known as indicators for evaluating oxidative stress in systemic circulation, including end-stage renal disease cases. We investigated factors associated with fraction of HNA [f(HNA)] in 112 pre-dialysis CKD patients (63.6 ± 14.0 years old; 59 males, 53 females) using a newly established anion-exchange column packed with hydrophilic polyvinyl alcohol gel as well as high performance liquid chromatography. Mean f(HNA) in our CKD patients was 30.0 ± 6.1%, higher than that previously reported for healthy subjects. In multiple regression analysis, age (β = 0.200, p = 0.014), eGFR (β = −0.238, p = 0.009), hemoglobin (β = −0.346, p < 0.001), and ferritin (β = 0.200, p = 0.019) were significantly and independently associated with f(HNA) (R2 = 0.356, p < 0.001). In addition, factors related to CKD-mineral and bone disorder (CKD-MBD), including intact-PTH (β = 0.218, p = 0.049) and 1,25-dihydroxyvitamin D (1,25(OH)2D) (β = −0.178, p = 0.040), were significantly and independently associated with serum f(HNA) (R2 = 0.339, p < 0.001), whereas fibroblast growth factor-23 was not. These findings indicate the importance of management of hemoglobin and ferritin levels, as well as appropriate control of CKD-MBD factors for a better redox state of serum albumin in CKD patients.

Background/Aims: Megalin mediates the uptake of glomerular-filtered iron in the proximal tubules. Urinary full length megalin (C-megalin) excretion has been found to be increased in association with megalin-mediated metabolic load to the endo-lysosomal system in proximal tubular epithelial cells (PTECs) of residual nephrons. In the present study, we investigated the association between urinary iron and C-megalin in chronic kidney disease (CKD) patients, and the possible harmful effect of iron in renal tubules. Methods: Urinary levels of iron and C-megalin were measured in 63 CKD patients using automatic absorption spectrometry and a recently-established sandwich ELISA, respectively. Results: Although both urinary C-megalin and urinary total protein levels were correlated with urinary iron (C-megalin: ρ = 0.574, p <0.001; total protein: ρ = 0.500, p <0.001, respectively), urinary C-megalin alone emerged as an independent factor positively associated with urinary iron (β = 0.520, p <0.001) (R² = 0.75, p <0.001). Furthermore, urinary iron was significantly and positively associated with urinary 8-hydroxydeoxyguanosine, an oxidative stress marker, while no association with other markers of renal tubular injury, i.e., β₂-microglobulin and N-acetyl-β-D-glucosaminidase, was noted. Conclusions: Our findings suggest that renal iron handling may be associated with megalin-mediated endo-lysosomal metabolic load in PTECs of residual nephrons and oxidative stress in renal tubules.

Background/Aims: Fibroblast growth factor (FGF)-23 and parathyroid hormone (PTH) are both potent phosphaturic hormones. Since they exert opposite effects on vitamin D metabolism, the measurement of 3 vitamin D metabolites; 25-hydroxyvitamin D (25-OH-D), 1,25-dihydroxyvitamin D (1,25(OH)₂D), and 24,25-dihydroxyvitamin D (24,25(OH)₂D), allows the distinction of the effects of FGF-23 from those of PTH. The aim of this study was to elucidate which factor, FGF-23 or PTH, plays a more important role in the regulation of vitamin D metabolites in subjects with estimated glomerular filtration (eGFR) ≥60 ml/min/1.73 m². Methods: Subjects with eGFR ≥60 ml/min/1.73 m² (n = 20) were enrolled and their serum levels of FGF-23, intact PTH, and vitamin D metabolites were determined. Results: Serum FGF-23 correlated inversely with 1,25(OH)₂D (r = -0.717, p = 0.0004) and the 1,25(OH)₂D/25-OH-D ratio (r = -0.518, p = 0.019), compared with a significant positive correlation between serum intact PTH and the 1,25(OH)₂D/25-OH-D ratio (r = 0.562, p = 0.010). Multiple regression analyses revealed serum FGF-23 as a significant factor that was associated with serum 1,25(OH)₂D (β = -0.593, p = 0.018), 1,25(OH)₂D/25-OH-D ratio (β = -0.521, p = 0.025), and the 24,25(OH)₂D/1,25(OH)₂D ratio (β = 0.632, p = 0.008), and intact PTH as a significant factor associated with the 1,25(OH)₂D/25-OH-D ratio (β = 0.445, p = 0.028). Conclusions: This study demonstrated that, even in subjects with eGFR ≥60 ml/min/1.73 m², FGF-23 might play an important role in the regulation of vitamin D metabolism. In addition to the established role of PTH, the association between FGF-23 and indices of vitamin D metabolism suggested the potential role of FGF-23 on phosphate metabolism in such patients.