BARCELONA: PRECONCEPTIONAL CARE
The effect of maternal diet on embryo development
Poor parental diet around the time of conception has the potential to trigger negative long term consequences for the wellbeing of the offspring. Laurentiu Craciunas reports from Barcelona.
The periconception period is a short but busy timeframe which includes maturation of gametes, fertilisation and the early days of embryo development. The imminent tasks of the embryo prior to its implantation are a switch from the parental genome to its own embryonic genome, the establishment of distinct fetal and placental lineages, metabolism activation and resetting of the "epigenetic" status for the new individual. These critical processes are sensitive to environmental factors and can modify subsequent development.
Paternal obesity and undernutrition have negative effects on sperm motility, DNA integrity and RNA profile, leading to reduced embryo potential and epigenetic reprogramming. Endocrine misregulation may affect later stages of pregnancy to increase the long term risks of cardiometabolic disease for the offspring.
On the other hand, maternal overnutrition - as reviewed by Professor Tom Fleming during an invited session in Barcelona - causes metabolite and lipid accumulation in the follicles that in turn may trigger mitochondrial damage with epigenetic and metabolic reprogramming in the fetus as an attempt to adapt to this abnormal environment. In contrast, maternal undernutrition stimulates extra-embryonic responses to compensate for the lack of nutrients by increased placental size and activity. The long term consequences for the offspring revolve around increased cardiometabolic disease risk.
Professor David Barker - a forerunner of Fleming at the University of Southampton, UK - was one of the first to suggest an early life origin of adult chronic disease by naming the periconception window as a key developmental window for the future adult. Extensive studies in mice linked low protein maternal diets with increased fetal growth that is predictive of adult overgrowth, cardiovascular and behavioural dysfunction.
Similar evidence of human early gestation disease risk was found as a consequence of the Dutch hunger winter, a five month period between 1944-1945 when pregnant women suffered famine at various gestations. Pregnancies exposed to poor nutritional intake during early gestation led to offspring at increased risk of coronary heart disease, glucose intolerance, accelerated ageing and poorer attention capacity in adult life. The same risks were not observed for pregnancies exposed to famine during late gestation.
Tom Fleming’s presentation in Barcelona also touched on the issue of concealed biochemical content of the embryo culture media used in assisted reproduction. The audience’s opinion was that providers should account for the potential long term consequences of different nutrients and should expand on the available information related to the exact biochemical content of their products.
In concluding the presentation, a new medical branch of periconceptional wellbeing was promoted in view of optimising parental lifestyles prior to embarking on the fertility journey.