Expression of placental glucose transporter proteins in pregnancies complicated by fetal growth disorders

Placental expression of glucose transporters GLUT‐1, GLUT‐3, GLUT‐8 and GLUT‐12 in pregnancies complicated by gestational and type 1 diabetes mellitus

“…In the course of further studies, the expression of GLUT-3 was successively confirmed in VE, VS, ST and CT of the human term placenta 8 . According to the proposed hypotheses, GLUT-3, being a transporter with a high affinity to glucose, whose highest expression in the trophoblast is found in the first trimester of pregnancy, might ensure energy supply to the fetus in conditions of insufficiently developed uteroplacental circulation during the early weeks of gestation 40 .…”

“…Available evidence suggests that GLUT-1 constitutes the basic glucose transporter in the human placenta, the positive expression of which was confirmed in ST, CT and VE 8 . It has been generally accepted, that in PGDM-complicated pregnancies, the expression of GLUT-1 protein is increased, whereas in the GDM population, the study results are ambiguous, with the majority indicating an increase in the transporter density only in patients requiring insulin therapy 8 .…”

“…Available evidence suggests that GLUT-1 constitutes the basic glucose transporter in the human placenta, the positive expression of which was confirmed in ST, CT and VE 8 . It has been generally accepted, that in PGDM-complicated pregnancies, the expression of GLUT-1 protein is increased, whereas in the GDM population, the study results are ambiguous, with the majority indicating an increase in the transporter density only in patients requiring insulin therapy 8 . The observed discrepancies in the latter group of patients can possibly be explained by the heterogeneity of study populations, various tissue fractions and methods used for quantitative analyses, as well as differences in GDM diagnostic criteria and thresholds of glycemic control 17,19,22,[30][31][32] .…”

“…Among major determinants of the placental glucose transfer, such as maternal-fetal glucose concentration gradient, uteroplacental blood flow and placental metabolism, the expression and activity of transporting proteins represents one of the most extensively studied factors. To date six proteins comprising the GLUT family of facilitative glucose transporters (GLUT-1, GLUT-3, GLUT-4, GLUT-8, GLUT-9, GLUT-12) have been discovered in the human placenta 8 . Each of the above-mentioned GLUT isoforms is responsible for sodiumindependent and gradient-compliant hexose transfer (except for GLUT-9 and possibly GLUT-12, which both demonstrate electrogenic properties), and differ with respect to substrate specificity, localization and tissue expression 9,10 .…”

“…Each of the above-mentioned GLUT isoforms is responsible for sodiumindependent and gradient-compliant hexose transfer (except for GLUT-9 and possibly GLUT-12, which both demonstrate electrogenic properties), and differ with respect to substrate specificity, localization and tissue expression 9,10 . In relation to the placenta, emerging evidence emphasizes the importance of alterations in the expression and activity of GLUT transporters in the pathogenesis of various pregnancy complications, in particular those associated with disorders of the intrauterine fetal growth 8 .…”