Premature babies often receive intravenous lipid emulsions to help meet their energy needs. However, little is known about how early exposure to lipids affects how skeletal muscle develops before birth. Muscle growth late in pregnancy depends on a balance between making new muscle fibers and building connective tissue, and extra lipids could shift this balance.
In this study, our collaborators asked whether short-term lipid exposure changes skeletal muscle development in the fetus. Using a sheep model, fetal lambs received intravenous Intralipid for several days during mid?gestation, at doses similar to those used in preterm infants. They then examined the tibialis anterior muscle to look at muscle size, structure, and gene activity.
Lipid infusion did not change overall fetal weight, muscle mass, muscle fiber size, or the amount of collagen in the muscle. However, it did change which genes were turned on or off. Genes that help muscle fibers form and mature were more active, while genes involved in making collagen and connective tissue were less active. Genes related to fat storage inside muscle and inflammation were not affected.
These results show that early lipid exposure can change muscle gene activity even before any visible changes in muscle structure appear. This suggests that nutrition can influence muscle development at a molecular level, and that these early changes may shape how muscle grows later in life—especially in preterm infants.
Find this paper on Pubmed and Experimental Physiology.