Erythrocyte transmembrane electron transfer in haemodialysis patients.
Level 4 - case-series / case-control
Case-control study combined with a single-group pre-post observational design
PubMed 17434051 · doi:10.1016/j.numecd.2005.11.011
What was done
The study evaluated erythrocyte transmembrane electron transfer capacity and oxidative stress biomarkers in 25 uremic patients on maintenance hemodialysis (aged 25–71 years; 14 males) compared to 25 age- and sex-matched healthy controls. Measurements were performed before and after a single mid-week hemodialysis session. Parameters assessed included erythrocyte velocity of ferricyanide reduction (RBC vfcy), erythrocyte glutathione (RBC GSH), plasma and red blood cell membrane malondialdehyde (P MDA and RBC MDA), plasma sulfhydryl groups (P SH), plasma vitamin C levels, and hemolysis percentage.
What was found
Pre-dialysis patients exhibited lower RBC GSH (0.68 ± 0.13 vs 0.80 ± 0.13 mg/mL, p < 0.01), P SH (266 ± 74 vs 406 ± 78 µmol/L, p < 0.01), and plasma vitamin C (7.0 ± 5.1 vs 21.5 ± 8.5 mg/L, p < 0.001) compared to controls, with higher P MDA (1.57 ± 0.52 vs 0.54 ± 0.29 nmol/mL, p < 0.001), RBC MDA (0.42 ± 0.13 vs 0.34 ± 0.16 nmol/mL, p < 0.05), and hemolysis (1.2 ± 0.3 vs 0.7 ± 0.3%, p < 0.001). Pre-dialysis RBC vfcy was similar to controls (13.1 ± 5.2 vs 12.9 ± 3.2 mmol/mL/h). Following hemodialysis, RBC vfcy significantly decreased (to 8.9 ± 4.5 mmol/mL/h, p < 0.001) and plasma vitamin C decreased (to 2.5 ± 1.4 mg/L, p < 0.001), while P MDA and RBC MDA decreased and P SH increased (to 413 ± 99 µmol/L, p < 0.001); hemolysis remained elevated.
Why it matters
While hemodialysis lowers circulating lipid peroxidation markers, it acutely reduces erythrocyte transmembrane electron transfer capacity and further depletes antioxidant defenses like vitamin C, potentially impairing cellular protection against oxidative challenge.
Limits
The study is limited by a small sample size (25 patients, 25 controls) and an uncontrolled pre-post evaluation of a single hemodialysis session. Clinical cardiovascular outcomes and long-term consequences of these biochemical shifts were not evaluated.
Cited by
- supports A single dialysis session in patients with renal failure decreases plasma vitamin C levels by roughly half.