Validation studies of a fluorescent method to measure placental glucose transport in mice. (15th January 2019)

• Record Type: Journal Article
• Authors: Kaur, Harleen; Wilson, Rebecca L.; Care, Alison S.; Muhlhausler, Beverly S.; Roberts, Claire T.; Gatford, Kathryn L.
• Is Part Of: Placenta. Volume 76(2019)
• Page Start: 23
• Page End: 29
• Publication Date: 2019-01-15
• Subjects: Placenta -- Nutrient transport -- Glucose -- Fluorescent tracer -- Mouse; Placenta -- Periodicals; Reproduction -- Periodicals; Placenta -- Periodicals; Placenta -- Périodiques; Reproduction -- Périodiques; 612.63
• DOI: 10.1016/j.placenta.2019.01.014
• Languages: English
• ISSNs: 0143-4004

Abstract

Abstract: Introduction: Proper placental function is essential for optimal fetal growth in utero. Placental transfer of nutrients to the fetus can be measured using radiolabelled tracers, but non-radioactive methods have potential advantages. This study aimed to develop a fluorescence-based method to measure placental glucose transport in mice. Methods: Time course and localisation of the IRDye 800CW 2-deoxyglucose were recorded (Lumina IVIS Live Imaging System) following tail vein injection into anaesthetised late pregnant mice. Fluorescent signals in placental and fetal tissues were assessed after injecting conscious dams with 10 nmol IRDye 800CW 2-deoxyglucose (3, 30, 60, 120 min) or vehicle. Specificity of dye uptake was determined by comparing uptake of IRDye 800CW conjugated to 2-deoxyglucose or carboxylate, at 2 and 24 h. Finally, we assessed relationships of fetal size and umbilical blood flow velocities with relative dye uptake. Results: In late pregnant mice, uterine fluorescent signal localised rapidly over placentas and remained consistent for >1 h. Signal intensity in whole and homogenised tissues increased in fetuses and decreased in placentas after 3 min and stabilised by 30 min post-injection. Relative fetal dye uptake at 2 and 24 h was greater in littermates with the highest compared to lowest placental efficiency; signals were similar for 2-deoxyglucose- or carboxylate-conjugated dyes. Relative fetal dye uptake correlated positively with fetal weight and placental efficiency and negatively with umbilical artery resistance indices. Conclusions: Fetal uptake of IRDye 800CW correlates with markers of placental blood flow and fetal growth, but does not specifically measure placental glucose transport. Highlights: Proper placental function is essential for optimal fetal growth in utero Radiolabelled tracer studies show impaired placental nutrient transport in complicated pregnancies Fluorescently labelled tracers offer an alternative approach to measuring placental transport Uptake of IRDye 800CW 2-DG does not specifically measure glucose uptake but correlates positively with placental efficiency Fetal IRDye 800CW 2-DG uptake provides an indirect measure of placental function in mice