An interaction between the interleukin-6 -174G>C gene variant and urinary protein excretion influences plasma oxidative stress in subjects with type 2 diabetes.
BACKGROUND
Microalbuminuria and subsequent progression to proteinuria and nephropathy is associated with increased oxidative stress, increased inflammatory cytokines and increased cardiovascular (CVD) risk. The common functional IL-6 -174G>C gene variant is also associated with elevated levels of inflammatory cytokines and CVD risk.


METHODS
The aim of this study was to examine the association between the IL-6 -174G>C gene variant with plasma total antioxidant status (TAOS) in 552 subjects with type 2 diabetes in relation to urinary protein excretion.


RESULTS
In subjects free from CVD, there was a significant interaction between urinary protein excretion (normoalbuminuria/ microalbuminuria/proteinuria) and the -174C allele (compared to -174GG) in determining plasma TAOS (p value for interaction = 0.03). In the -174C allele carriers there was a significant association between plasma TAOS and urinary protein excretion: normalbuminuria v microalbuminuria v proteinuria: 44.30% +/- 11.32 vs. 39.74% +/- 14.83 vs. 37.93% +/- 16.42, ANOVA p = 0.025. In those with CVD, no interaction or association was observed with the -174C allele (p = 0.246).


CONCLUSIONS
The IL-6 -174G>C gene variant is associated with differences in plasma oxidative stress in response to altered protein excretion in subjects with type 2 diabetes.
Stephens
Jeffrey W
JW
Centre for Cardiovascular Genetics, British Heart Foundation Laboratories, Royal Free and University College London Medical School, 5 University Street, London WC1E 6JF, United Kingdom. rmhajst@ucl.ac.uk
Hurel
Steven J
SJ
Acharya
Jayshree
J
Humphries
Steve E
SE