Effects of Low Protein Diet on Nuclear Factor Erythroid 2–Related Factor 2 Gene Expression in Nondialysis Chronic Kidney Disease Patients

Abstract

Low protein diets (LPD; 0.6 g/kg/day), prescribed for nondialysis chronic kidney disease (CKD) patients, have demonstrated numerous benefits. LPDs may modulate inflammation and oxidative stress through the nuclear factor erythroid 2-related factor 2 (Nrf2), which encodes antioxidant and phase II detoxifying enzymes. LPDs also inhibit or antagonize nuclear factor kB (NF-kB) activity, which orchestrates inflammatory and oxidative stress responses. The objective of this study was to evaluate the effects of LPD on Nfr2 and NF-κB messenger RNA (mRNA) expression in nondialysis CKD patients. In this longitudinal study, a LPD was prescribed for 30 nondialysis CKD patients for 6months. Peripheral blood mononuclear cells were isolated, and quantitative real-time polymerase chain reaction analysis was performed to evaluate Nrf2, NF-κB, and NADPH quinine oxidoreductase-1 mRNA expression. Thiobarbituric acid-reactive substance (TBARS) levels, a marker of lipid peroxidation, were also evaluated. (Age 55.5±14.0years; body mass index 29.1±5.9kg/m2; glomerular filtration rate 35.6±12.2mL/minute). After 6months of nutritional intervention, Nrf2 mRNA expression increased from 0.85 (0.47-1.56) to 1.28 (0.63-2.63) nmol/mL (P=.03), and TBARS levels were significantly decreased from 1.78 (1.31-2.38) to 1.30 (1.07-2.22) nmol/mL (P=.04). NF-κB mRNA expression showed no significant difference after 6months, but the Nrf2/NF-κB ratio was increased. In this study, a LPD appeared to modulate Nrf2 expression and decrease the levels of TBARS in nondialysis CKD patients. However, more studies are needed to confirm the effectiveness of LPD on the modulation of transcription factors involved with oxidative stress and inflammation in nondialysis CKD patients.