REN and Hypertension: Furthermore, maternal protein restriction has been associated with alterations in fetal astrocytogenesis, extracellular matrix structure, neuronal differentiation, mitochondrial function, death cell programming, expression of proteins related to the brain renin–angiotensin system (associated with hypertension), enhanced activity in the fetal hypothalamic–pituitary–adrenal axis (HPA), and hypomethylation in the ACE-1 brain gene promoter in animal models [46].