Congratulations to Danielle Berbrier for Successfully Defending Her Dissertation

Danielle Berbrier successfully defended her PhD Oral Defence in Currie Room 304 - Tassone on June 9, 2025.

The title of their Thesis:
"Control of peripheral vascular function in females with polycystic ovary syndrome"

Abstract:
Polycystic ovary syndrome (PCOS), affecting ~10% of reproductive-aged females, is associated with potent and interrelated cardiovascular disease risk factors including hypertension, vascular dysfunction, and insulin resistance. As a result, PCOS itself is now considered a risk factor for the development of cardiovascular disease. However, the cardiovascular pathophysiology of PCOS remains poorly understood, partly due to the presence of comorbidities such as obesity, which limit our ability to prevent cardiovascular diseases in PCOS. Given that obesity is independently associated with adverse cardiovascular outcomes, it remains unclear whether cardiovascular disease risk is elevated in PCOS secondary to obesity, or as a function of PCOS itself. To address key gaps in this literature, the purpose of this dissertation was to investigate the peripheral vasculature as a key site of cardiovascular dysfunction in otherwise healthy females with PCOS. All studies compared vascular function between young, lean, and otherwise healthy females with PCOS and control (CTRL) females without PCOS. Study 1 examined changes in vascular resistance and blood pressure during the cold pressor test (CPT). Vascular and blood pressure responses to the CPT were greater in PCOS than CTRL and appeared to be mediated in part by the detrimental effects of elevated androgens. Building on these findings, Study 2 assessed the cardiometabolic consequences (i.e., insulin resistance and impaired glycemic control) on peripheral vasculature in PCOS. Study 2 assessed glucose-stimulated increases in blood flow during an oral glucose tolerance test (OGTT). Increases in blood flow in response to the OGTT were absent in PCOS, underscoring the profound vascular consequences of PCOS. Finally, Study 3 evaluated acute exogenous ketone supplementation, a promising intervention to improve indices of cardiometabolic health, as a means of improving peripheral vascular and metabolic function in females with PCOS. Exogenous ketone supplementation ameliorated OGTT-induced endothelial dysfunction and glycemia control in females with PCOS. Taken together, these findings highlight the critical role of peripheral vasculature in cardiovascular dysfunction in lean females with PCOS, underscoring the need for improved understanding and targeted interventions for this often-overlooked PCOS cohort.

Oral Defence Comittee:
Dr. Jenna Gibbs (Supervisor), Dr. Shane Sweet, Dr. Celena Scheede, Dr. Tyler Churchward-Venne, Dr. Anna Stanhewicz and Dr. Jean Gotman.