Association between estradiol and endothelium-dependent vasodilation in the gingiva of young premenopausal women

Abstract Background This study aimed to investigate the associations of age and estradiol levels with gingival blood flow (GBF), with a specific focus on endothelium-dependent vasodilation in premenopausal women during the menstrual (MEN) and periovulatory (OVU) phases of the menstrual cycle. Methods In this prospective, non-randomized, repeated-measures study, twenty healthy women (19-35 years, cycle length 25-32 days) participated. Blood samples were collected before GBF measurements to confirm the MEN or OVU cycle phase and to assess hormone levels using an automated electrochemiluminescence immunoassay. GBF was measured via laser speckle contrast imaging (LSCI) at the maxillary anterior region after applying physiological saline to the gingival sulcus of tooth FDI #21 (control) and 10 mg/mL acetylcholine (ACh) solution to FDI #12 (test). These two sites were selected as the most distant locations that the LSCI system can capture simultaneously. Data were analyzed using a mixed-effects regression model. Results No significant overall differences between the MEN and OVU phases were found in baseline GBF ( p = 0.792), maximum blood flow change (dmax, p = 0.415), or area under the curve (AUC, p = 0.773). Age negatively correlated with dmax (slope: -7.98, p = 0.033) and AUC (slope: -205, p = 0.041), regardless of phase. Estradiol was negatively associated with dmax (slope: -1.71, p = 0.019) and AUC (slope: -44, p = 0.024) during MEN but not during OVU. Conclusions Elevated estradiol levels during MEN were associated with a reduced vasodilatory response; however, this was not observed during OVU, suggesting a complex, phase-specific interaction between estradiol and endothelial function in the oral mucosa. Trial registration Trial registry number at www.clinicaltrials.gov : NCT06454084 (Date of registration: 06.06.2024).