Prolactin predicts changes in endothelial function, arterial stiffening in postmenopausal women
Elevated serum prolactin levels within the normal range appear to predict worsening endothelial function over time in apparently healthy postmenopausal women, a study has found. In a relatively young segment of this population, the hormone is also predictive of vascular ageing as indicated by accelerated arterial stiffening.
A sex hormone involved in female breast development and lactation, prolactin has been associated with hypertensive disorders and cardiac remodelling in healthy individuals. “In postmenopausal women, prolactin may be particularly important because the prevalence of hypertension and cardiovascular risk significantly rise after menopausal transition,” the authors said.
In a cohort of 201 postmenopausal women who were followed for 3 years, baseline prolactin levels significantly correlated with changes in flow-mediated dilation (FMD; p=0.005), a measure of endothelial function, at follow-up. One SD increase in baseline prolactin was specifically associated with a mean decrease of 0.45 percent in FMD, and this was independent of age, body mass index and systolic blood pressure (BP), among others. [J Hum Hypertens 2017;31:520–524]
Baseline levels of the hormone were also independently associated with changes in mean BP (p=0.021), peripheral diastolic BP (p=0.004) and new-onset hypertension (odds ratio, 1.235; p=0.001).
The authors noted a significant interaction between baseline prolactin and age for changes in pulse-wave velocity (PWV; p=0.036), a measure of aortic stiffness. Subsequently, a subgroup analysis based on median age revealed that among women younger than 55 years, prolactin independently predicted changes in PWV over time (p=0.008).
Mean age of the cohort was 56.1 years, and mean years of menopause was 7.8. Median prolactin levels at baseline was 8.1 ng ml−1, while median FMD was 5 percent at baseline and 4.02 percent at follow-up. Mean PWV was 8.57 m s−1 at baseline and 8.74 m s−1 at follow-up.
Given that postmenopausal women are at increased risk of hypertension and progression of arteriosclerosis and that prolactin predicts new-onset hypertension, the results “suggest that prolactin may play an early role in the increased prevalence of hypertension after menopausal transition via acceleration of endothelial dysfunction,” the authors said.
“Arterial stiffening, endothelial dysfunction and hypertension are strongly inter-related,” they explained. “Prolactin may adversely affect all three edges of this spurious triangle,” with recent data indicating that the hormone exerts pleiotropic adverse haemodynamic and proatherosclerotic effects, which may mediate increased cardiovascular risk. [J Mol Endocrinol 2014;52:R95–R106; J Hypertens 2014;32:216–224; J Am Coll Cardiol 2014;63:2491–2502]
There is also evidence supporting a direct effect of prolactin on the arterial wall, which may contribute to endothelial dysfunction, pathologic vascular tone, arterial stiffening, increased pulse pressure, systolic and diastolic hypertension, and further end organ disease. [JAMA 2012;308:875–881; Eur Heart J 2013;34:2159–2219]“Whether prolactin could be of utility as a possible therapeutic target to prevent hypertension and arterial stiffening, especially early after menopausal transition, warrants further investigation,” the authors said.