Investigation of the Distinct Mechanisms Involved in Inflammatory Resolution Between Healthy Men and Women

Study Overview
=================
Brief Summary
-----------------
Important differences exist between sexes in incidence, disease patterns and outcomes in coronary artery disease that is not well understood. It is likely that key differences in the underlying biological mechanism, in particular in inflammatory responses, play a part in underpinning these differences. Previous evidence demonstrates that healthy females appear to be more adept at resolving inflammation compared to healthy males. Since inflammation is thought to be a key initiating phenomenon in coronary artery disease the investigators will examine the differences in inflammatory resolution between the sexes in healthy volunteers.

Detailed Description
-----------------
Inflammation is a key process in triggering events caused by coronary artery disease. Indeed, large scale trials have tested the efficacy of a range of anti-inflammatory approaches. However, whilst some of these confirmed the utility of such approaches in leading to reductions in coronary artery disease; the benefits came at a cost with an increased risk of infection. In their previous work the investigators discovered that, women demonstrate enhanced resolution of inflammation compared to males. This accelerated resolution coincided with improved blood vessel function and health. It is also now accepted that a failure of resolution plays an important part in the enhanced inflammation seen in coronary artery disease. Whether the differences in the incidence of coronary artery disease between men and women might be related to differences in their capacity to mount a resolution response is unknown. To determine whether inflammatory resolution differs between sexes the investigators will use the validated cantharidin-induced model of acute inflammation in healthy volunteers. Previous published studies have shown when cantharidin is applied to the skin it causes acantholysis and blister formation. It is a safe, reproducible technique with no permanent scarring or ill-effects. The investigators will study the effects on inflammatory responses by measuring the levels of cells, inflammatory mediators and markers of vascular function in blister fluid, urine, saliva and blood. Cantharidin application will be applied to separate areas of the skin over the course of three days to create three small blisters in order to examine different timepoints of the inflammatory process. The blister fluid will then be collected on the fourth day which will be analysed according to standard laboratory techniques including flow cytometry.

Official Title
-----------------
Investigation of the Distinct Mechanisms Involved in Inflammatory Resolution Between Healthy Men and Women: RESOLVE-SEX

Conditions
-----------------
Inflammation

Intervention / Treatment
-----------------
* Drug: Cantharidin


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Healthy male and female volunteers Aged 18-45 Volunteers who are willing to sign the consent form Exclusion Criteria: Healthy subjects unwilling to consent Pregnant, or any possibility that a subject may be pregnant unless in the latter case a pregnancy test is performed with a negative result Current breast feeding History of any serious illnesses, including recent infections or trauma Subjects taking systemic medication (other than the oral contraceptive pill) Subjects with recent (2 weeks) or current antibiotic use Subjects with any history of a blood-borne infectious disease such as Hepatitis B or C virus, or HIV

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Female<br>The participant will initially attend either in person or virtually for a screening visit for eligibility. Cantharidin will be applied on the second visit to the forearm, back or abdomen (depending on patient preference) via 1cm2 cantharidin soaked filter paper. The particpant will then attend for two further cantharidin applications (24 hr and 48 hr after the first application). 72 hours after initial cantharidin application the blister fluid will be collected. | Drug: Cantharidin<br>* 0.1% cantharidin solution in acetone from 0.7% stock solution of cantharone is prepared and applied immediately. 10 μl of cantharidin per disc.<br>* Other names: Cantharone 0.1%;|
| Experimental: Male<br>The participant will initially attend either in person or virtually for a screening visit for eligibility. Cantharidin will be applied on the second visit to the forearm, back or abdomen (depending on patient preference) via 1cm2 cantharidin soaked filter paper. The particpant will then attend for two further cantharidin applications (24 hr and 48 hr after the first application). 72 hours after initial cantharidin application the blister fluid will be collected. | Drug: Cantharidin<br>* 0.1% cantharidin solution in acetone from 0.7% stock solution of cantharone is prepared and applied immediately. 10 μl of cantharidin per disc.<br>* Other names: Cantharone 0.1%;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of the presence or not of blister at each timepoint over 24-72h between the sexes | Visual inspection as to the presence of an intact blister of 24hr, 48 hr and 72 hr cantharidin blisters | 24 hours, 48 hours, 72 hours | 
| Comparison of blister volume at each timepoint over 24-72h between the sexes | Blister fluid sampled and weighed to determine volume | 24 hours, 48 hours, 72 hours | 
| Comparison of blister cell number at each timepoint over 24-72 hours between the sexes | Blister fluid collected from 24 hour, 48 hour and 72 hour cantharidin blisters. Fluid will be analysed using standard laboratory techniques including labelled flow cytometry | 24 hours, 48 hours, 72 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of blister leukocyte subsets (neutrophil and monocyte) between the sexes at each timepoint | Blister fluid collected from 24 hour, 48 hour and 72 hour cantharidin blisters. Fluid will be analysed using standard laboratory techniques including labelled flow cytometry | 24 hours, 48 hours, 72 hours | 
| Comparison of blister lactate levels and LDH between the sexes at each timepoint | Blister fluid collected from 24 hour, 48 hour and 72 hour cantharidin blisters. Analysis as per standard laboratory techniques. | 24 hours, 48 hours, 72 hours | 
| Comparison of cell death, necrotic, and apoptotic cell numbers between the sexes at each timepoint | Blister fluid collected from 24 hour, 48 hour and 72 hour cantharidin blisters. Fluid will be analysed using standard laboratory techniques including labelled flow cytometry | 24 hours, 48 hours, 72 hours | 
| 4. Comparison of markers of blister efferocytosis between the sexes at each timepoint | Blister fluid collected from 24 hour, 48 hour and 72 hour cantharidin blisters. Fluid will be analysed using standard laboratory techniques including labelled flow cytometry | 24 hours, 48 hours, 72 hours |