Obesity's Hidden Link to High Blood Pressure in Prematurely Born Teens
"New research reveals how obesity impacts the delicate balance of hormones, raising blood pressure risks for adolescents born preterm."
The survival rates of infants born preterm have significantly improved due to advancements in prenatal and neonatal care. However, these early births can lead to a higher lifetime risk of chronic health issues, including hypertension and cardiovascular disease. Understanding the underlying causes of this increased risk is crucial for developing effective prevention and treatment strategies.
One key area of investigation is the renin-angiotensin system (RAS), a critical regulator of blood pressure and cardiovascular function. Research indicates that perinatal events can induce changes in the RAS, potentially leading to long-term health consequences. The RAS consists of two main pathways: the traditional angiotensin-converting enzyme (ACE)/angiotensin II (Ang II)/Ang II type 1 receptor pathway and the regulatory angiotensin-converting enzyme 2 (ACE2)/Ang-(1-7)/Mas receptor pathway. An imbalance in these pathways, favoring Ang II, can contribute to hypertension.
Obesity has also been linked to increased Ang II expression, which may elevate blood pressure. However, the combined effect of obesity and premature birth on the RAS remains unclear. A recent study explored this complex relationship in adolescents born preterm, revealing significant insights into how obesity amplifies the risk of hypertension by disrupting the balance within the renin-angiotensin system.
The Study's Key Findings: Unpacking the Obesity-RAS Connection
A cross-sectional analysis was conducted on 175 adolescents born prematurely with very low birth weight. Researchers quantified plasma and urinary levels of Ang II and Ang-(1-7), comparing these levels between subjects with overweight/obesity (body mass index ≥85th percentile) and those with a healthy weight (body mass index <85th percentile). The study used generalized linear models, adjusting for factors like race and antenatal corticosteroid exposure to ensure accurate results. The results revealed several important associations:
- Elevated Ang II/Ang-(1-7) Ratio: Overweight/obesity was associated with a higher ratio of plasma Ang II to Ang-(1-7), suggesting an imbalance in the RAS.
- Increased Ang II Levels: Subjects with overweight/obesity had higher levels of Ang II in their plasma.
- Decreased Ang-(1-7) Levels: Conversely, overweight/obesity was associated with lower levels of Ang-(1-7) in the circulation.
- Higher Urinary Ang II/Ang-(1-7) Ratio: The ratio of urinary Ang II to Ang-(1-7) was also higher in overweight/obese subjects, indicating a similar imbalance in the kidney.
The Road Ahead: Strategies for Prevention and Treatment
Given these findings, potential strategies to prevent or treat disease in individuals born preterm could focus on targeting the RAS to inhibit Ang II and promote Ang-(1-7) expression. Further research is needed to fully understand the complex interplay between obesity, the RAS, and cardiovascular health in this vulnerable population. By addressing these factors, healthcare professionals can develop more effective interventions to improve the long-term health outcomes for adolescents born prematurely.