Getting Under the Skin of the Menopausal Hot Flush

Recruiting

• Conditions: Menopause

• Registration Number: NCT06222073
• Lead Sponsor: Liverpool John Moores University

Brief Summary

The aim of this research is to 1) test how the skin blood vessels and sweat glands function in women who experience hot flushes by using skin microdialysis to deliver small amounts of substances to the skin that cause increased skin blood flow and sweating, and 2) examine the structure of the skin blood vessels and sweat glands in the skin of women who experience hot flushes by taking a very small skin biopsy. Any changes in the function or structure of the skin blood vessels or sweat glands in women with hot flushes would increase our understanding of what causes hot flushes and help to design effective treatments.

Detailed Description

In a cross-sectional design, participants will attend the laboratory on two separate occasions. At visit 1, anthropometric measurements will be recorded and a venous blood sample will be collected to determine hormone status (e.g. oestradiol level) and pro-inflammatory markers (e.g. IL-8, Prostaglandin 2E). Participants will then undergo assessment of post-ganglionic skin blood vessel and sweat gland responsiveness (transdermal/cutaneous microdialysis). At visit 2 (\~7 days later), participants will undergo a skin punch biopsy.

Study Timeline

• Study Start: 2023-01-01
• Study First Submitted: 2023-09-18
• Study First Submitted QC: 2024-01-23
• Study First Posted: 2024-01-24
• Status Verified: 2024-10
• Last Update Submitted: 2025-03-13
• Last Update Posted: 2025-03-18
• Primary Completion: 2025-10-31
• Study Completion: 2025-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: Female
• Target Recruitment: 36

Inclusion Criteria

• Aged >45 years for the postmenopausal cohort and aged 18-30 years for the premenopausal cohort
• Female
• Amenorrhoeic for >6 months (postmenopausal criteria)
• >4 hot flushes per day (symptomatic postmenopausal criteria)
• Eumenorrhoeic with regular menstrual cycles (premenopausal criteria)
• Healthy
• Non-smoker
• BMI 18-30 kg/m2
• No history of cardiovascular or respiratory disease
• No history of metabolic disease e.g. type II diabetes
• Drink <14 units of alcohol per week
• Not taking any medication or treatments to alleviate hot flushes

Exclusion Criteria

• Aged < 18 years or 31-44 years
• Male
• Smokers
• Medical history of cardiovascular/respiratory disease
• Medical history of metabolic disease e.g. type II diabetes
• Drink >15 units of alcohol per week
• On medication or treatments to alleviate hot flushes or have taken such medication/treatment within the previous 6 months
• BMI of <18 or >30 kg/m2
• Vaccination (<1 week) due to induced systemic inflammatory reaction
• Local forearm infection
• Allergy to local anaesthetic/Marcain/amide-group anaesthetics
• Pregnant

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Skin function/responsiveness	Baseline (visit 1)	The non-dominant forearm will be inserted with 3 cutaneous microdialysis membranes. Each of the membranes will be perfused with either of the following (randomly assigned to the three sites); increasing doses of Acetylcholine, Sodium Nitroprusside (SNP) or calcitonin gene-related peptide (CGRP) to stimulate skin blood flow (and sweating) which will be assessed using laser Doppler probes housed directly over the membrane sites. The dose-response curves for skin blood flow will be mathematically modelled via non-linear regression curve fitting. The maximum responses and the effective concentration causing 50% of the maximal response (EC50) will be calculated from the nonlinear regression modelling.
Sweat gland function/responsiveness	Baseline (visit 1)	The non-dominant forearm will be inserted with 3 cutaneous microdialysis membranes. Each of the membranes will be perfused with either of the following (randomly assigned to the three sites); increasing doses of Acetylcholine, Sodium Nitroprusside (SNP) or calcitonin gene-related peptide (CGRP) to stimulate sweating (and skin blood flow) which will be assessed using laser Doppler probes housed directly over the membrane sites. The dose-response curves for sweating will be mathematically modelled via non-linear regression curve fitting. The maximum responses and the effective concentration causing 50% of the maximal response (EC50) will be calculated from the nonlinear regression modelling.
Oestradiol	Baseline (visit 1)	A venous blood sample will be taken and analysed to establish the oestradiol level (pg/mL).
Interleukin-6 (IL-6)	Baseline (visit 1)	A venous blood sample will be taken to assess circulating inflammatory markers/cytokines.; Interleukin-6 (IL-6) will be measured (pg/mL) using an ELISA.
Skin structure (blood vessels)	Baseline (visit 2)	7 days following assessment of skin function/responsiveness (to allow the hyperaemic response to subside), a single 3mm skin punch biopsy will be taken from the non-dominant forearm. The sample will be processed and stained to highlight blood vessels and endothelia. The samples will be stained with fluorescein-labelled ulex europaeus, an endothelium-specific antibody. Confocal microscopic imaging of the samples will be analysed to quantify capillary density e.g. capillary count/length of the epidermal surface (capillaries/mm) and capillary diameter.
Interleukin-8 (IL-8)	Baseline (visit 1)	A venous blood sample will be taken to assess circulating inflammatory markers/cytokines.; Interleukin-8 (IL-8) will be measured (pg/mL) using an ELISA.
Tumour Necrosis Factor alpha (TNF-α)	Baseline (visit 1)	A venous blood sample will be taken to assess circulating inflammatory markers/cytokines.; TNF-α will be measured (pg/mL) using an ELISA.
Prostaglandin E2	Baseline (visit 1)	A venous blood sample will be taken to assess circulating inflammatory markers/cytokines.; Prostaglandin E2 will be measured (pg/mL) using an ELISA.
C-reactive Protein (CRP)	Baseline (visit 1)	A venous blood sample will be taken to assess circulating inflammatory markers/cytokines.; CRP will be measured (mg/L) using an ELISA.
Calcitonin Gene Related Peptide (CGRP)	Baseline (visit 1)	A venous blood sample will be taken to assess circulating inflammatory markers/cytokines.; CGRP will be measured (pg/mL) using an ELISA.
Skin structure (sweat glands)	Baseline (visit 2)	7 days following assessment of skin function/responsiveness (to allow the hyperaemic response to subside), a single 3mm skin punch biopsy will be taken from the non-dominant forearm. The sample will be processed and stained to highlight sweat glands. The samples will be stained with protein gene product 9.5, a sweat gland/nerve fibre antibody. Confocal microscopic imaging of the samples will be analysed to quantify sweat gland density.

Trial Locations

Locations (1)

Liverpool John Moores University; 🇬🇧 Liverpool, Merseyside, United Kingdom