Intrauterine Growth Restriction Influences Vascular Remodeling and Stiffening in the Weanling Rat More than Sex or Diet

Intrauterine growth restriction (IUGR) increases the incidence of adult cardiovascular disease (CVD). The sex-specific developmental mechanisms for IUGR-induced and western high fat diet (HFD) modification of CVD remain poorly understood. We hypothesized a maternal HFD in the Sprague-Dawley rat would augment IUGR-induced CVD in the offspring through decreased cardiac function and increased extracellular matrix (ECM) remodeling and stiffness in a sex-specific manner. HFD or regular diet (Reg) was given from 5 weeks prior to mating through postnatal day 21 (PND21). IUGR was induced by uterine artery ligation at embryonic day 19.5 (term=21.5 days). At PND 21, echocardiographic assessments were made and carotid arteries tested for vascular compliance using pressure myography. Arterial samples were quantified for ECM constituents or fixed for histologic evaluation. The insult of IUGR (IUGR+Reg and IUGR+HFD) led to increased mechanical stiffness in both sexes (P<0.05). The combination of IUGR+HFD increased diastolic blood pressure 47% in males (M) and 35% in females (F) compared to the Con+Reg (P<0.05). ECM remodeling in IUGR+HFD caused fewer (M=-29%, F=-24%) but thicker elastin bands (M=18%, F=18%) and increased total collagen (M=49%, F=34%) compared to Con+Reg arteries. Remodeling in IUGR+HFD males increased medial collagen and soluble collagen (P<0.05). Remodeling in IUGR+HFD females increased adventitial collagen and wall thickness (P<0.05) and decreased MMP-2, AGEs, and RAGEs (P<0.05). In summary, both IUGR+Reg and IUGR+HFD remodel ECM in PND21 rats. While IUGR+HFD increases BP, IUGR but not HFD increases vascular stiffness suggesting a specific mechanism of vascular remodeling that can be targeted to limit future disease.