Estrogen and Microvascular Function

Study Overview
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Brief Summary
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The goal of this study is to learn how long-term use of estrogen affects blood vessels in healthy adults who were assigned male at birth. Participants will: give one blood draw of 5 mL have a camera placed under the tongue to take pictures of blood vessels have 2 laser Doppler microdialysis catheters placed on the forearm to monitor blood vessels before and after local drug infusion Researchers will compare blood vessel function of those who take estrogen supplements to those who do not.

Official Title
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Sex-specific Effects of Continuous Estrogen on Human in Vivo Microvascular Function

Conditions
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Estrogen, Cardiovascular Diseases, Microvasculature

Intervention / Treatment
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* Drug: Nω-nitro-L-arginine methyl ester (L-NAME)
* Drug: Acetylcholine
* Drug: Sodium Nitroprusside


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults aged 18-60 years Identify as assigned male at birth (AMAB) +/- continuous estrogen treatment for a minimum of 1 year. Blood pressure <140/ < 90 mmHg No more than 1 cardiovascular risk factor Exclusion Criteria: BMI >35 Medications that could alter cardiovascular control Rash, skin disease, or pigmentation disorders Anemia Kidney Disease Known skin allergies Smoking or tobacco use within last 6 months Coronary Artery Disease > 1 cardiovascular risk factor Hypertension Diabetes Hypercholesterolemia Hyperlipidemia Bleeding disorders Use of anti-coagulants Allergies to study drugs Erectile dysfunction medication in the past 6 months Use of topical/non-topical steroids in last 6 months Internal mouth sores

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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Male

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| AMAB + continuous estrogen<br>Identify as assigned male at birth (AMAB) who have had continuous estrogen treatment for a minimum of 1 year. | Drug: Nω-nitro-L-arginine methyl ester (L-NAME)<br>* L-NAME will be infused locally through microdialysis catheters.<br>Drug: Acetylcholine<br>* ACh will be infused locally through microdialysis catheters.<br>Drug: Sodium Nitroprusside<br>* SNP will be infused locally through microdialysis catheters.<br>|
| AMAB - continuous estrogen<br>Identify as assigned male at birth (AMAB) who have not had continuous estrogen treatment for a minimum of 1 year. | Drug: Nω-nitro-L-arginine methyl ester (L-NAME)<br>* L-NAME will be infused locally through microdialysis catheters.<br>Drug: Acetylcholine<br>* ACh will be infused locally through microdialysis catheters.<br>Drug: Sodium Nitroprusside<br>* SNP will be infused locally through microdialysis catheters.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in blood vessel dilation | Cutaneous vascular conductance in response to acetylcholine, L-NAME, and sodium nitroprusside infusions will be calculated as percentage of cardiovascular conductance. | 2 hours | 
| Change in Perfused Vessel Density | Total vessel density (TVD) will be calculated using the DeBacker Score manual analysis on all images that have a minimum microcirculation image quality score (MIQS) of 10. Perfused vessel density (PVD) will be calculated by multiplying total vessel density (TVD) x proportion of perfused vessels (PPV%). | 0.5 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Transgender, Hormone Replacement Therapy