Relationship between thioredoxin and thioredoxin-binding protein in patients with gestational diabetes mellitus

This study examined the clinical and biological significance of thioredoxin (Trx) and thioredoxin-binding protein (TrxBP), which are redox-active proteins that control multiple biological functions, in gestational diabetes.

We measured serum concentrations of Trx, TrxBP, insulin and other blood parameters, as well as insulin resistance and glucose tolerance in pregnant women with or without gestational dieabetes mellitus (GDM) (34/34) at the early second trimester.

Contrary to diabetes patients, serum TrxBP levels were lower in women with GDM than healthy pregnant controls. The serum insulin concentrations were higher in GDM, but the difference was not statistically significant. Furthermore, the intracellular redox potential ratio (Trx/TrxBP) of GDM patients was higher than that of the control group.

During pregnancy, the mother is potentially subjected to glucotoxicity as well as oxidative stress (OS) to help the foetus absorb more nutrients. Our results suggest that the Trx/TrxBP system may mediate a compensating mechanism. Reduced TrxBP levels and consequent enhanced Trx activity may alleviate OS and protect the foetus from hypoglycaemia. We hypothesise that the decrease in TrxBP levels is not a consequence of GDM, but rather is an instance of the active functional role of TrxBP in maternal development, unifying redox regulation and glucose metabolism.