Due to the study’s small sample, further research is needed to understand the role of bromocriptine in reducing blood pressure and artery stiffness in youth with type 1 diabetes (T1D).
Bromocriptine, a medication typically used to treat Parkinson disease and type 2 diabetes, was linked to lower blood pressure and less stiff arteries in patients with type 1 diabetes (T1D) after 1 month, according to a small study published in Hypertension.
“We know that abnormalities in the large vessels around the heart, the aorta and its primary branches, begin to develop in early childhood in people with type 1 diabetes,” said Michal Schäfer, PhD, lead study author as well as researcher and fourth-year medical student at the University of Colorado School of Medicine, in a press release. “We found that bromocriptine has the potential to slow down the development of those abnormalities and decrease the risk for cardiovascular disease in this population.”
The study included 34 participants, with 13 male and 21 female patients with T1D. The mean (SD) age was 15.9 (2.6) years, and mean T1D duration was 5.8 years
The mean hemoglobin A1c level in the cohort was 8.6% (1.1%) and mean body mass index percentile was 71.4 (26.1). Additionally, glycosylated hemoglobin A1c (HbA1c) was 12% or lower in all participants, with an HbA1c level of 6.5% or higher indicating diabetes.
Participants were randomly assigned into 2 groups, with 17 participants receiving bromocriptine quick-release therapy and 17 receiving a placebo once daily.
In phase 1, participants received bromocriptine or placebo for 4 weeks. After a 4-week “wash-out” period where neither group received treatment, participants switched treatments. In phase 2, participants originally in the intervention group instead received placebo, and those in the placebo group received bromocriptine quick-release therapy for 4 weeks.
With this study design, each participant served as their own control for comparison.
The study authors measure blood pressure and aortic stiffness at baseline and after each study phase.
To determine aortic stiffness, the authors assessed the large arteries with cardiovascular MRI and measured pulse wave velocity.
After 4 weeks of bromocriptine therapy, patients saw a significant decrease in blood pressure compared with placebo. Bromocriptine therapy resulted in an average systolic blood pressure decrease of 5 mm Hg and average diastolic blood pressure decrease of 2 mm Hg at the end of 4 weeks.
Bromocriptine therapy was also linked to reduced aortic stiffness. Improvement was most notable in the ascending aorta, with a lowered pulse wave velocity of about 0.4 meters per second and an increase in distensibility or elasticity of 8%. In the thoraco-abdominal aorta, the therapy was associated with a lowered pulse wave velocity of about 0.2 meters per second, with a 5% increase in distensibility.
“A stiff aorta predisposes a patient to other health issues, such as organ dysfunction or atherosclerosis and higher stress or strain on cardiac muscle,” said Schäfer. “We were able to take it a notch further and show, using more sophisticated metrics, that these central large arteries are impaired, and impairment among adolescents and young adults with Type 1 diabetes may be decelerated with this drug.”
According to the authors, these findings suggest bromocriptine quick-release therapy may improve aortic stiffness in youth with T1D. The small study population serves as a major limitation, but the authors are planning larger, longer-term studies.
Schäfer M, Browne LP, Truong U, et al. bromocriptine improves central aortic stiffness in adolescents with type 1 diabetes: arterial health results from the BCQR-T1D study. Hypertension. Published online December 6, 2022. doi:10.1161/HYPERTENSIONAHA.122.19547