High-fat diet effects on amniotic fluid volume and amnion aquaporin expression in non-human primates

Abstract

Western style, high‐fat diet (HFD) and associated high lipid levels have deleterious effects on fetal and placental development independent of maternal obesity and/or diabetes. Our objectives were to determine whether HFD without development of obesity would alter amniotic fluid volume (AFV) and amnion aquaporin (AQP) expression in a non‐human primate model. Japanese macaques were fed either a control diet or HFD before and during pregnancy. The four quadrant amniotic fluid index (AFI) was used as an ultrasonic estimate of AFV at 120 days gestation. Amnion samples were collected at 130 days gestation by cesarean section and AQP mRNA levels were determined by quantitative RT‐PCR. Similar to that in human, AQP1, AQP3, AQP8, AQP9, and AQP11 were expressed in the macaque amnion with significant differences in levels among AQPs. In macaque, neither individual AQPs nor expression profiles of the five AQPs differed between control and non‐obese HFD animals. There were regional differences in AQP expression in that, AQP1 mRNA levels were highest and AQP8 lowest in reflected amnion while AQP3, AQP9, and AQP11 were not different among amnion regions. When subdivided into control and HFD groups, AQP1 mRNA levels remain highest in the reflected amnion of both groups. The HFD did not significantly affect the AFI, but AFI was positively correlated with AQP11 mRNA levels independent of diet. Collectively, these data suggest that HFD in pregnant non‐obese individuals may have at most modest effects on AFV as the AFI and amnion AQP expression are not substantially altered.

Effects of maternal western-style diet on amniotic fluid volume and amnion VEGF profiles in a nonhuman primate model

“…Of interest, analysis of regional differences in amnion gene expression demonstrated that VEGF and sFlt-1 levels differed among the three regions with VEGF expression lowest in secondary placental amnion and highest in reflected amnion, while sFlt-1 expression lowest in the primary placental amnion but highest in the reflected amnion. These regional differences were consistent with the differential gene expression profiles characteristic of different amnion regions (Han et al 2008), as well as with the differential aquaporin gene expression shown in our recent HFD pregnant macaque (Cheung et al 2018) and human (Bednar et al 2015) studies. The significance of such differences is unclear and may be related to the permeability characteristics of the three amnion regions.…”

“…The absence of HFD effects on amnion VEGF and sFlT‐1 gene expression are similar to findings in our recent study of pregnant macaques fed a HFD (Cheung et al. ) in that expression levels of five aquaporins in the amnion was not affected by the high fat intake in animals with the resistant phenotype. Of interest, analysis of regional differences in amnion gene expression demonstrated that VEGF and sFlt‐1 levels differed among the three regions with VEGF expression lowest in secondary placental amnion and highest in reflected amnion, while sFlt‐1 expression lowest in the primary placental amnion but highest in the reflected amnion.…”

“…), as well as with the differential aquaporin gene expression shown in our recent HFD pregnant macaque (Cheung et al. ) and human (Bednar et al. ) studies.…”

“…Animals were subjected to an ultrasound exam at approximately 120 days gestation (0.7 term), as described in our recent publication (Cheung et al. ;). During the exam, the four‐quadrant amniotic fluid index (AFI) was measured (GE Voluson 730 Expert; Kretztechnik, Zipf, Austria) by one ultrasonographer (AEF) and used as an index of AFV.…”

“…Maternal metabolic parameters (body weight, plasma fasting glucose, triglycerides, insulin, and leptin) were assessed in the dams at regular intervals as described in detail previously (Roberts et al 2014). Animals were subjected to an ultrasound exam at approximately 120 days gestation (0.7 term), as described in our recent publication (Cheung et al 2018;). During the exam, the fourquadrant amniotic fluid index (AFI) was measured (GE Voluson 730 Expert; Kretztechnik, Zipf, Austria) by one ultrasonographer (AEF) and used as an index of AFV.…”