During development, the fetal kidney is susceptible to adverse early-life events, leading to changes in structure and function, namely renal programming
[76]. Renal programming is the most commonly studied mechanism behind the hypertension of developmental origins
[4][5][11]. A reduced nephron number can develop during pregnancy through childhood to later life in different animal models of renal programming
[77]. Maternal insults need only last for 1–2 days to impair nephrogenesis, resulting in a permanent reduction in the nephron number
[78]. Accordingly, the main phenotype of renal programming associated with a reduced nephron number is hypertension
[77].
An impaired ADMA–NO pathway is tightly linked to oxidative stress in determining renal programming
[74]. NO deficiency in pregnancy induced by NOS inhibitor N
G-nitro-
l-arginine methyl ester (L-NAME) caused renal programming, coinciding with increased oxidative stress in adult offspring
[72]. Additionally, maternal NO deficiency was able to modify more than 2000 renal transcripts in a 1-day-old offspring kidney. It has been found that several genes belonging to the RAS and arachidonic acid metabolism pathway contribute to the pathogenesis of programmed hypertension
[72]. In a prenatal dexamethasone exposure model
[69][78], offspring rats developed hypertension coinciding with a reduced nephron number, increased plasma ADMA levels, and reduced renal NO production. Likewise, the links between oxidative stress and a reduced nephron number have been reported in a caloric restriction model
[35] and a streptozotocin-induced diabetes model
[49]. Moreover, the researchers' prior work has demonstrated that ADMA can impair nephrogenesis
[49]. Metanephroi grown in 2 or 10 µM ADMA displayed reduced nephron numbers in a dose-dependent manner
[49]. When the researchers treated cultured metanephroi with 10 µM ADMA, the next-generation sequencing (NGS) analysis identified 1221 differential expressed genes
[79]. Among them,
Ephx2,
Avpr1a,
Npy1r,
Hba2, and
Hba-a2, have been linked to programmed hypertension in other models
[80][81]. Together, these observations support the notion that oxidative-stress-induced renal programming contributes to the hypertension of developmental origins.