Revolutionary technique investigates the cause of psoriasis

Dr. Wen Lynn Ho inserts a microdialysis catheter into the skin on my left forearm under the watchful eye of Professor Bart Ramsey. I do not suffer from psoriasis myself but I acted as a control in this study – for comparison.

Psoriasis is a chronic skin disease resulting from abnormal immune function and is characterized by the presence of scaly psoriatic plaques which are areas of inflammation and excessive skin production. The exact cause remains unknown but the brain may be involved given that stress can trigger psoriatic flares.

In my latest research at the University of Limerick (UL) Medical School, I have been leading  a team who have successfully applied a new method of monitoring chemicals in the body – a method known as microdialysis – which has the potential to revolutionise the diagnosis and treatment of this disease

Microdialysis involves the temporary insertion of microscopic hollow tubes or artificial blood vessels through the skin. Artificial blood (or Ringer) solution is then passed through the tubes at a very slow rate allowing any chemicals or biological markers to be trapped and carried away by microdialysis catheters and collected.

What is revolutionary about this technique is that it can go into the living skin. We can measure skin chemistry in real-time without any drugs. This is the first time inIreland that skin chemistry has been measured by microdialysis. Currently the only way to monitor skin chemistry is by biopsy.  However, as biopsy involves punching a hole in the skin causing damage and wound formation, it does not provide a real-time physiological picture as the skin tested is dead.

By putting these tiny artificial blood vessels into the skin and fooling the skin into thinking that these are real blood vessels, we can extract chemicals without doing any damage.

Read more:

Rapid quantification of histamine in human psoriatic plaques using microdialysis (article in press, Journal of Chromatography)

 (article in press, Journal of Chromatography)

Related Article:

UL discovery could replace biopsies

Slow protein clearance ‘clue to Alzheimer’s’

Amyloid plaques build up in the brains of people with Alzheimer's disease. Image: BBC Health

The BBC News website this week reports on the latest research to suggest that people with Alzheimer’s disease clear a damaging protein from their brains more slowly than those who are healthy. With an ageing population,  dementia, including Alzheimer’s, is currently seen as one of the main health challenges in Ireland the UK.

Amyloid plaques are one of the hallmarks of Alzheimer’s disease. Amyloid is a general term for protein fragments that the body produces normally. Beta amyloid is a protein fragment snipped from an amyloid precursor protein. In a healthy brain, these protein fragments are broken down and eliminated. For some reason, in Alzheimer’s disease, the fragments accumulate to form hard, insoluble plaques.

The findings from this study suggests that people with Alzheimer’s disease clear the damaging protein from their brains 30% more slowly than those who are healthy suggesting that  it is the poor clearance of the protein, not the build-up, that is the problem. Admittedly it’s a small study – just 24 people were looked at, but exciting, and could help the understanding of the disease.

Not meaning to blow my own trumpet (ahem!) but in 2008 my research group showed how the amyloid protein might be toxic in higher concentration …by inappropriately increasing the concentrations of a neurotransmitter called glutamate in the hippocampus – a brain region long associated with Alzheimer’s disease*. It’s well known that high concentrations of glutamate can damage local nerve cells and thus impair the functioning of the hippocampus.

It’s exciting to see the pieces of evidence coming together as the search for an effective treatment for dementia continues apace.

*  O’Shea S.D., Smith I.M., McCabe O.M., Cronin M.M., Walsh D.M., O’Connor W.T. Sensors. 2008; 8(11):7428-7437.