Norermi Firzana Alfian

Cellular memory, or epigenetic memory, represents the capacity for cells to retain information beyond the underlying DNA sequence. This heritable characteristic is primarily governed by epigenetic mechanisms which enable cells to maintain specialized characteristics across divisions. This persistent cellular state is essential for fundamental biological processes, such as maintaining tissue identity and facilitating cell differentiation, especially embryonic cells. Early-stage perturbations such as assisted reproductive technologies (ART) and nutritional stress links embryonic exposures to adult health and disease within the Developmental Origins of Health and Disease (DOHaD) framework. Crucially, memory established during early embryogenesis links these epigenetic modifications to adult long-term phenotypes related to metabolic disorders. These modifications—including DNA methylation, histone modifications, and non-coding RNAs—support cellular memory transmission across cell divisions, and in certain organisms, can be transmitted across generations without alterations to the DNA sequence. This review synthesizes recent advances in epigenetic pathways that mediate cellular memory, highlights critical preimplantation windows of vulnerability and outlines gaps necessary for mammalian developing interventions that safeguard future generations.

Bovine serum albumin (BSA), the most commonly used protein in preimplantation embryo culture media, performs a variety of physiological functions. However, its involvement in long-term effects remains largely unclear. To investigate its physiological importance in culture media, we examined the developmental and metabolic consequences of BSA deprivation during preimplantation stages in mice. Embryos cultured in BSA-free media during specific time windows exhibited impaired blastocyst formation, with continuous deprivation from the two-pronuclei (2PN) stage significantly reducing trophectoderm (TE) and inner cell mass (ICM) cell numbers (p < 0.05), indicating compromised viability. Short-term BSA deprivation similarly disrupted lineage allocation, underscoring the sensitivity of early embryos to nutrient availability during cell fate determination. Although birth rates remained unaffected, suggesting compensatory mechanisms, longitudinal analysis revealed sex-specific metabolic dysfunction. Male offspring developed progressive glucose intolerance by 16 weeks, exhibiting elevated fasting glucose levels (p < 0.05) and impaired glucose clearance, whereas females showed no significant alterations in glucose metabolism. This study demonstrates that protein restriction during the preimplantation period not only disrupts early embryonic development but also programs long-term metabolic dysfunction, underscoring the importance of optimizing culture conditions in assisted reproductive technologies to minimize future health risks.