Menopause Transition, Sex Hormone Deficiency and Autonomic and Vascular Function

University of Minnesota100 enrolled

Overview

This is a longitudinal study to determine the influence of the menopause transition on autonomic and vascular function. PI Keller-Ross has published data demonstrating that postmenopausal females have greater sympathetic neural reactivity during a stressor compared with age-matched males and younger females and males. A paucity of literature exists, however, on the role of the menopause transition in autonomic function because the majority of experimental studies on menopause physiology are cross-sectional and/or focused on older, postmenopausal females . The influence of age on HTN is robust, whereas the effects of menopause are still unclear. Preliminary data demonstrate a clear association between age and sympathetic activity in females; how the transition through menopause influences these relations, however, remains unknown. The study will enroll 80 midlife (45-55 years of age) females to measure longitudinally the trajectory of autonomic and vascular function during the transition through menopause. The study hypothesizes that through the menopause transition, an increase in sympathetic activity and an impaired baroreflex sensitivity and endothelial function will emerge.

Study Type

OBSERVATIONAL

Enrollment

100

Conditions

Menopause

Interventions

No intervention

Eligibility

Sex: FEMALEMin age: 45 YearsMax age: 55 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Female * age 45-55 years * premenopausal * not using any medications determined to affect autonomic function * eumenorrheic * not planning to become pregnant for the duration of participation in the study * English-speaking, literate, willing and able to provide informed consent. Exclusion Criteria: * Diabetes * pregnant or breastfeeding * cardiac or pulmonary disorders * severe obesity (body mass index \[BMI\] ≥ 40 kg/m 2 ) * hypertension * obstructive sleep apnea * current use of heart or blood pressure medications, current use of hormonal contraceptives or other forms of exogenous sex hormones * report of nicotine/tobacco use in the last six months, report of current alcohol abuse, * history of treatment with chemotherapy/radiation * coagulopathy disorders and/or use of anticoagulant medications, and current use of anxiolytics and/or antidepressants.

Outcomes

Primary Outcomes

MSNA- Burst frequency

measured in bursts/min Microneurography to measure MSNA: Microneurography is a direct measurement of electrical activity of peripheral sympathetic nerves. A tungsten microelectrode is placed in a peripheral nerve (Figure 8) to record real-time activity from efferent sympathetic vasoconstrictor nerve fibers. MSNA is the gold-standard measure for sympathetic activity Participants attend experimental visits annually until they enter perimenopause, at which point they will attend such visits every six months.

Time frame: up to 5 years

MSNA- Burst incidence

measured in bursts/100 heartbeats Microneurography to measure MSNA: Microneurography is a direct measurement of electrical activity of peripheral sympathetic nerves. A tungsten microelectrode is placed in a peripheral nerve (Figure 8) to record real-time activity from efferent sympathetic vasoconstrictor nerve fibers. MSNA is the gold-standard measure for sympathetic activity Participants attend experimental visits annually until they enter perimenopause, at which point they will attend such visits every six months.

Time frame: up to 5 years

MSNA- total activity

Microneurography to measure MSNA: Microneurography is a direct measurement of electrical activity of peripheral sympathetic nerves. A tungsten microelectrode is placed in a peripheral nerve (Figure 8) to record real-time activity from efferent sympathetic vasoconstrictor nerve fibers. MSNA is the gold-standard measure for sympathetic activity Participants attend experimental visits annually until they enter perimenopause, at which point they will attend such visits every six months.

Time frame: up to 5 years

Secondary Outcomes

cardiovagal baroreflex sensitivity: ms/mmHg

Cardiovagal baroreflex is estimated by responses in the R-R interval of the ECG to changes in systolic pressure. Participants attend experimental visits annually until they enter perimenopause, at which point they will attend such visits every six months.

Time frame: up to 5 years

sympathetic baroreflex sensitivity: bursts/100heartbeats/mmHg

Sympathetic baroreflex is estimated by responses in MSNA to changes in diastolic pressure. Participants attend experimental visits annually until they enter perimenopause, at which point they will attend such visits every six months.

Time frame: up to 5 years

vascular conductance (mL/100mL tissue/min/mmHg)

vascular conductance via venous occlusion plethysmography will be quantified by FBF/mean arterial pressure Participants attend experimental visits annually until they enter perimenopause, at which point they will attend such visits every six months.

Time frame: up to 5 years

Menopause Transition, Sex Hormone Deficiency and Autonomic and Vascular Function

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes

Central Contacts