Background:
Previous literature has shown a strong negative effect of angiotensin II (ANGII) on bone metabolism within mouse models. Additionally, psychological stress has been associated with activation of the renin-angiotensin-aldosterone system (RAAS). Stress has also been related to lower total bone mineral density (TBMD). However, there is controversy in the literature examining the relationship between the RAAS and bone metabolism within humans and stress has not been considered as a direct link between these systems.
Purpose:
We aimed to examine the relationship between stress-induced RAAS activation and TBMD and total bone mineral content (TBMC).
Methods:
Participants were placed on a sodium controlled diet for three days. Participants then underwent two hours rest, one hour mental stressor, and two hours recovery with hourly collections of blood/urine samples. Renin, ANGII, aldosterone, TBMD and TBMC were measured.
Results:
This study recruited 586 adolescents (mean age 16±1.116) with 51% women and 62% African-American and 38% Caucasian. Overall, relationships were observed between ANGII and aldosterone, and TBMC and TBMD controlling for age, race, and BMI. During stress, aldosterone was related to TBMD (r=-.150, p<0.05) and ANGII was related to TBMC (r=-.156, p<0.05) and TBMD (r=-.139, p<0.05). When comparing males and females, only females demonstrated a relationship between TBMC and ANGII in response to stress (stress: r=-.229, p<0.05; post-stress: r=-.277, p<0.01) and between aldosterone and TBMC (stress: r=-.199, p<0.05) and TBMD (stress: r=-.250, p<0.01). Renin was not significantly correlated with TBMD nor TBMC in any population.
Conclusion/Interpretations:
These data suggest that stress-induced RAAS activation may be associated with lower TBMD and TBMC in girls. Despite small correlations, consistency across multiple measures of RAAS activation being apparent in adolescents is significant. This observation may indicate that stress activation of RAAS contributes to bone remodeling in early life.
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