Albumin used in human IVF contain different levels of lipids and modify embryo and fetal growth in a mouse model

Investigation of refractive index dynamics during in vitro embryo development using off-axis digital holographic microscopy

Embryo quality is a crucial factor affecting live birth outcomes. However, an accurate diagnostic for embryo quality remains elusive in the in vitro fertilization clinic. Determining physical parameters of the embryo may offer key information for this purpose. Here, we demonstrate that digital holographic microscopy (DHM) can rapidly and non-invasively assess the refractive index of mouse embryos. Murine embryos were cultured in either low- or high-lipid containing media and digital holograms recorded at various stages of development. The phase of the recorded hologram was numerically retrieved, from which the refractive index of the embryo was calculated. We showed that DHM can detect spatio-temporal changes in refractive index during embryo development that are reflective of its lipid content. As accumulation of intracellular lipid is known to compromise embryo health, DHM may prove beneficial in developing an accurate, non-invasive, multimodal diagnostic.

Lipid Changes in the Peri-Implantation Period with Mass Spectrometry Imaging: A Systematic Review

Mass spectrometry imaging is a sensitive method for detecting molecules in tissues in their native form. Lipids mainly act as energy stores and membrane constituents, but they also play a role in lipid signaling. Previous studies have suggested an important role of lipids in implantation; therefore, our aim was to investigate the lipid changes during this period based on the available literature. The systematic literature search was performed on Ovid MEDLINE, Cochrane Library, Embase, and LILACS. We included studies about lipid changes in the early embryonal stage of healthy mammalian development published as mass spectrometry imaging. The search retrieved 917 articles without duplicates, and five articles were included in the narrative synthesis of the results. Two articles found a different spatial distribution of lipids in the early bovine embryo and receptive uterus. Three articles investigated lipids in mice in the peri-implantation period and found a different spatial distribution of several glycerophospholipids in both embryonic and maternal tissues. Although only five studies from three different research groups were included in this systematic review, it is clear that the spatial distribution of lipids is diverse in different tissues and their distribution varies from day to day. This may be a key factor in successful implantation, but further studies are needed to elucidate the exact mechanism.

Mechanisms of lipid metabolism in uterine receptivity and embryo development

Metabolic regulation plays important roles in embryo development and uterine receptivity during early pregnancy, ultimately influencing pregnancy efficiency in mammals. The important roles of lipid metabolism during early pregnancy have not been fully understood. Here, we described the regulatory roles of phospholipid, sphingolipid, and cholesterol metabolism on early embryo development, implantation, and uterine receptivity through production of cannabinoids, prostaglandins, lysophosphatidic acid, sphingosine-1-phosphate, and steroid hormones. Moreover, the impacts of lipids and fatty acids on embryo development potential and the related epigenetic modifications are also discussed. This review aims to elucidate the modulations of lipid metabolism on uterine receptivity and embryo development, contributing to novel strategies to establish dietary balanced lipids and fatty acids for reducing early embryo loss.