Clinical Technologies

A number of techniques are used within a clinical setting as part of research projects being carried out at UCD Charles Institute & Clinic. 

Microdialysis

Microdialysis is a technique that lets you measure levels of compounds in the fluid around cells in virtually any tissue in the body, including skin. It involves leaving needles placed in the tissue - in this case the skin - but it is relatively non-invasive and patients may experience a small discomfort when a needle is being inserted.

In microdialysis, several sterilised needles connect to a catheter, and up to 10 catheters might be applied at a time, depending on the substances being applied or measured. There are established protocols for microdialysis (Schmelz et al., 1997; Anderson et al., 1991; Steinhoff et al., 2003; Ikoma et al., 2004). Initially, saline is put through the catheters for 10-15 minutes to wash out substances that may have been released due to the needle going in and then fluids are collected for 30 minutes. In some catheters, neuropeptides/endothelium-derived peptides can also be added to saline (1 pM - 100 nM). At the end of the procedure, catheters are removed from the skin without discomfort or the formation of a scar.

Iontophoresis

Iontophoresis uses a gentle electric current to deliver drugs through the skin. In practice, when a gentle electric current is applied to the skin, it enables ‘ionized' forms of drugs to move through through the sweat ducts, sebaceous glands, hair follicles and sites where the skin is not perfectly sealed.

Using this technique means that certain water-soluble drug compounds can be delivered into the body in a convenient and non-invasive way without the need to take them orally, in which case they could get destroyed in the digestive system or broken down by the liver before they get a chance to work.

The iontophoresis unit has drug reservoir that holds and releases the drug and a segment to apply the current. The electrodes that are placed on the skin are small metal plates. These electrodes are placed on the skin about 5cm apart, then the current is passed through for between 10 and 60 seconds so that the ionised drugs can penetrate the skin. 

Skin Barrier Function

What is the largest organ in the human body? It’s not the brain, it’s not the liver, it’s the skin. Your skin makes up 12-15% of your entire weight, and one if its most important functions is to protect against losing water and other important molecules (such as ions and proteins) from the body.

As well as stopping your contents leaking out, skin prevents potentially dangerous things from the environment getting in, like foreign objects, microbes, parasites and harsh chemicals.

The main part of the skin involved in this barrier function is the outermost layer, or epidermis. This layer of cells (including as keratinocytes, fibroblasts and nerve endings) forms an interface between your body and its environment.

The bulk of this barrier is made up by the outermost layer of the epidermis itself, which is named the stratum corneum. Its specialised cells called corneocytes are organised in water-repellent lipids to work as the “brick wall”, and the lipids prevent skin from being too dry to crack. Unlike a brick wall though, the stratum corneum uses a dynamic system that can respond to external influences, and it is replenished by underlying cells called keratinocytes.

The barrier can become damaged or compromised in many skin conditions or diseases. This is a particularly significant issue in psoriasis and atopic dermatitis, and it means the body’s internal immune system is exposed to various external factors from which it is normally protected.

To better understand skin barrier function and how to address it when it is compromised, Prof Steinhoff’s group have developed lab-based or in vitro models. They include a three-dimensional model of skin that can be used to look at what happens when the skin cells and structures are exposed to drugs and other biomolecules. The group have also developed a microdialysis system that can measure and monitor skin-barrier function by collecting proteins from the fluid within skin and analysing its contents.

Biobank

UCD Charles Institute of Dermatology is developing the first Irish skin biobank. This facility for future skin-related research brings together contemporary research facilities at UCD Charles Institute, UCD affiliated teaching hospitals and the patient-related Irish Skin Foundation.

The biobank will store skin-related biological samples from patients with skin conditions including rosacea, psoriasis and epidermolysis bullosa, as well as samples from volunteer healthy control subjects. Sample-related information will be stored electronically in a purpose-designed secure database. 

The development of this valuable research resource will enable future researchers to access biological material that will facilitate dermatology studies. The impact of this research will be the improved understanding of skin diseases that will ultimately produce better therapies for patients. Together with the international collaborator research network being established at the Institute, this skin biobank will make it possible for patients both in Ireland and abroad to be treated more successfully.