Impact of AGT rs5050(T>G) variants on associations between estradiol and angiotensinogen levels: Multi-Ethnic Study of Atherosclerosis (MESA).
AIMS: Angiotensinogen plays an essential role in maintaining circulatory homeostasis. AGT rs5050(T > G) has been identified as a regulator of the transcription of AGT mRNA, with differential expression between sexes. We sought to determine if rs5050(T > G), an estrogen response element, modifies the relationship between estrogen and angiotensinogen levels. METHODS: rs5050(T > G) was genotyped, and plasma angiotensinogen levels were measured in 4,831 MESA participants, including postmenopausal women, on hormone therapy (n = 709) or not (n = 1,551), and 2,581 men. Linear regression models were employed to determine the associations of angiotensinogen with rs5050(T > G) allele dosage; and to evaluate whether rs5050(T > G) modifies the association between estradiol and angiotensinogen, with a main effect term and interaction term between rs5050(T > G)*estradiol. Estimated marginal means (EMMs) were used to further evaluate the effect of estradiol on angiotensinogen across different rs5050 alleles (T > G). RESULTS: rs5050TT had the highest median levels of angiotensinogen, followed by TG and GG. Adjusted main effect model showed positive associations between estradiol and angiotensinogen, with each rs5050T allele associated with 0.329 SD higher log-angiotensinogen levels (CI 95% 0.293, 0.365). The interaction rs5050(T > G)*estradiol was not significant, with EMMs exhibiting overlapping slope confidence intervals across genotypes. The proportion of the variance in angiotensinogen explained by modeling increases from 47.9% to 51.6% when including rs5050(T > G) or interation rs5050(T > G)*estradiol in the model. CONCLUSIONS: rs5050(T > G) is associated with circulating angiotensinogen levels, but rs5050(T > G) alleles do not influence the relationship between estradiol and angiotensinogen. This suggests that estrogen's effect on angiotensinogen regulation occurs independently of rs5050(T > G), despite its location within an estrogen-responsive element.