Results
We found that native (-SH) and total thiol (-SH+-S-S-) levels were lower
in patients with CKD (stage 3-5) and HD compared with the control
subjects (230.7±59.9 and 202.6±79.7 µmol/L; 267.7±66.4, and 264.9±98.6
µmol/L respectively). However, disulfide levels were higher in patients
with CKD and HD compared with the control subjects (18.5±7.4 and
31.2±12.3 µmol/L, respectively). Moreover, disulfide levels were
significanlty high in the patients receiving HD compared with both
patients with CKD (stage 3-5) and control subjects (31.2±12.3µmol/L,
18.5±7.4 µmol/L and 16.3±4.8 µmol/L respectively). Disulfide levels in
HD patients increased significantly compared with patients with CKD and
control subjects (p=0.001). In addition, plasma IMA levels were
significantly different between control and CKD (stage 3-5) and control
and HD groups (p = 0.001, Table 1).
Native and total thiol levels showed negative correlation with IMA,
blood urea nitrogen (BUN), and creatinine levels (r=-0.628, p=0.001;
r=-0.747, p=0.001, r=-0.732, p=0.001). In addition, it showed positive
correlation with glomerular filtration rate (GFR) (r= 0.835, p=0.001;
r=0.824, p=0.001). There was no correlation between disulfide levels and
age and GFR (Table 2). In patients receiving HD, native and total thiols
in pre-and post-dialysis were significantly different (p=0.001), but
disulfide levels did not significantly change (p=0.0152) by a single
dialysis session. Serum albumin and CRP levels were significantly
different before and after the dialysis session (p=0.001, Table 3).
Therefore, we also calculated adjusted native thiol, total thiol, and
disulfide levels based on albumin concentrations in HD patients both
before and after the dialysis. After albumin correction, there was no
significant difference anymore in the native and total thiol levels of
pre- and post- dialysis patients (p=0.143, p=0.567), however significant
difference was observed in the disulfide levels (p=0.001, Table 4).