Serum concentrations of retinol-binding protein 4 in women with and without gestational diabetes

Abstract

Aims/hypothesis Pregnancy is characterised by temporarily increased insulin resistance. Gestational diabetes occurs when pancreatic beta cell function is unable to compensate for this insulin resistance. Retinol-binding protein 4 (RBP4) could be related to insulin resistance. We hypothesised that RBP4 is elevated in gestational diabetes. Methods Serum RBP4, transthyretin and retinol were crosssectionally measured in 42 women with gestational diabetes and 45 pregnant controls. Of these, 20 women with and 22 without gestational diabetes were included in an additional longitudinal study. RBP4 was determined by enzyme immunometric assay (EIA) and western blot. Results Women with gestational diabetes had lower RBP4 EIA and western blot levels than controls (median 6.8 [interquartile range, 3.9-14.3] vs 11.3 [7.8-19.9] μg/ml, p<0.001 and 25.1 [21.7-29.6] vs 26.6 [23.5-32.2] μg/ml, p=0.026). Transthyretin and the RBP4:transthyretin molar ratio were comparable between the groups. Serum retinol was lower (p<0.001) and the RBP4 Western blot level: retinol molar ratio was higher in women with gestational diabetes (p=0.044). RBP4 was not associated with the glucose or homeostasis model assessment of insulin resistance (HOMA-IR), but in gestational diabetes the RBP4:retinol molar ratio correlated with blood glucose and negatively with 2 h post-load insulin. The RBP4:transthyretin ratio correlated with HOMA-IR and fasting insulin in controls. In women with gestational diabetes RBP4 EIA and western blot levels increased after delivery. Retinol increased in both groups, while transthyretin and the RBP4:transthyretin ratio were not altered after parturition. Conclusions/interpretation RBP4 measured by two different techniques is not elevated, but the RBP4:retinol molar ratio is higher and correlates with fasting blood glucose in women with gestational diabetes. Thus, the RBP4:retinol ratio and the RBP4:transthyretin ratio are more informative than RBP4 levels alone when assessing insulin-glucose homeostasis during pregnancy.

Vitamina A e diabetes gestacional

“…[38][39][40] Accordingly, women with gestational diabetes have also been suggested as a group in risk of presenting reduced VA levels. 4 In accordance with Basu et al, (1997) 38 among interfering factors in seric vitamin A concentration, the presence of DM does not seem to affect ingestion neither intestinal absorption. This way, the deficient state observed must be related to the vitamin's impaired transportation.…”

“…49 Considering that the presence of gestational diabetes aggravates the tendency to VAD development in these women, the provision of proper quantities of this vitamin for their infants will be damaged, making them vulnerable to presenting limited stock of vitamin A in the body. 4,6,34 This way, this nutritional disorder may cause an increase in mortality, morbidity and blindness in these children. It is known then that pre-school children with deficient vitamin A reserves in the body present a higher risk of death by diarrhea, respiratory infections, and chicken pox than children with adequate vitamin A state, since it has a protective role against these complications.…”

Contrasting effects of type 2 and type 1 diabetes on plasma RBP4 levels: The significance of transthyretin

“…These observations coupled with direct effects of RBP4 demonstrated in animal and cell culture models (5, 13) imply a strong role of RBP4 in obesitymediated insulin resistance. Recently, extensive trials in insulinresistant adults and children from multiple ethnic backgrounds revealed a strong association between plasma RBP4 concentrations with insulin resistance, obesity, and metabolic syndrome components (16)(17)(18)(19)(20). In addition, interventions that ameliorate insulin resistance in humans also reduced plasma RBP4 levels (11,14,(21)(22)(23).…”

Gestational diabetes: a risk of puerperal hypovitaminosis A?

“…In appropriate nutrient conditions, 90% of circulating RBP4 is connected to retinol (RBP4 concentration in adults is 2-3μM) (Bellovino et al 2003 (Metzger et al 2007). Similar to Diabetes Mellitus type 2, GDM is associated with both insulin resistance and the decreased function of β-cells, which are unable to meet the increasing organic needs for insulin (Krzyzanowska et al 2008). It occurs in 1-14% of all pregnancies depending on the population studied, and it is associated with the increased perinatal morbidity and mortality (Sociedade Brasileira de Diabetes 2009).…”