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.

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.

Inclusion Criteria:

1. Healthy male and female volunteers
2. Aged 18-45
3. Volunteers who are willing to sign the consent form

Exclusion Criteria:

1. Healthy subjects unwilling to consent
2. Pregnant, or any possibility that a subject may be pregnant unless in the latter case a pregnancy test is performed with a negative result
3. Current breast feeding
4. History of any serious illnesses, including recent infections or trauma
5. Subjects taking systemic medication (other than the oral contraceptive pill)
6. Subjects with recent (2 weeks) or current antibiotic use
7. Subjects with any history of a blood-borne infectious disease such as Hepatitis B or C virus, or HIV