Low birth weight is associated with reduced nephron number and increased blood pressure in adulthood in a novel spontaneous intrauterine growth-restricted model in Yucatan miniature Swine.

BACKGROUND

Impaired fetal growth and rapid postnatal growth are associated with programming of hypertension and metabolic syndrome in adulthood.

OBJECTIVES

This study evaluated this phenomenon in a novel spontaneous intrauterine growth-restricted (IUGR) model in Yucatan miniature pigs.

METHODS

IUGR piglets (n = 6, 3 days old, 0.73 ± 0.11 kg) were paired with a normal weight (NW) same-sex littermate (n = 6, 1.11 ± 0.13 kg), fed milk replacer for 4 weeks followed by a standard diet ad libitum for 5 h/day. At 9 months of age, arterial blood pressure (BP) telemeters were implanted to assess BP before (0.5% NaCl) and after (4.5% NaCl) a 7-day salt-loading period. At 10 months of age, nephron numbers were determined.

RESULTS

Prior to sexual maturity, IUGR pigs showed greater (p < 0.05) relative feed intake and experienced significant catch-up growth. Adult IUGR pigs also had higher BP (diastolic BP: 93.8 ± 5.5 vs. 90.0 ± 8.7 mm Hg, p < 0.05) and 43% fewer nephrons per kidney (p < 0.05). Nephron number was positively associated with birth weight and negatively correlated with BP (p < 0.05). Acute salt loading increased BP in both groups (p < 0.05); however, the degree of salt sensitivity was similar between groups (p > 0.05).

CONCLUSIONS

In conclusion, IUGR piglets have reduced nephron endowment associated with a modest BP increase in early adulthood. This new model can be used to conduct longitudinal mechanistic studies on the early programming phenomenon.