Skin Deep - Clinical & Cosmetic Dermatology Blog

Skin Deep is a blog for dermatologists and skin care professionals with focus on theoretical, cosmetic and aesthetic dermatology. This blog is associated with ‘Dermatologists Sans Borders’ one of the largest curated groups of skin care professionals on facebook. If you are looking for non-technical information, please visit http://skinhelpdesk.com


Filling the Gap

Human fibroblast
Human fibroblast (Photo credit: glyn_nelson)
Dermal fillers are an important tool in the armamentarium of an aesthetic dermatologist in the management of ageing skin these days and its popularity is on the rise. But among dermal fillers the safe materials are short lasting while long lasting materials are not really safe. Certain materials that claim to be safe and long lasting by fibroblast activation do not have appropriate physico-mechanical properties. They are ‘bony hard’ and rarely even deposits bone! An ideal filler material should be biodegradable, non-cytotoxic, enhance fibroblast adherence and proliferation. It should also have ideal physico-mechanical properties. Scientists from University of Akron, Ohio doing research on biopolymers have stumbled upon such a material.[1] It is still early days and the research team has not even declared it as a probable dermal filler material.

‘Pseudo’ poly (aminoacids) such as L-Tyrosine polyurethanes (LTUs) have been synthesized by the structural modification of poly (aminoacids) by incorporation of non-peptide bonds into the polymer’s backbone. These bioplolymers have superior mechanical properties (particularly their excellent elasticity) without cytotoxic degradation products. They augment fibroblastic adhesion and proliferation that is even tunable to certain extend by subtle changes in the polymer structure.

I dare go to the extent of predicting it as a next generation hair loss treatment because of its ideal rheological properties as a scaffold for blood-vessel generation as I hypothesised before.

GlaxoSmithKline has a unique topical steroid molecule called GW870086 in the pipeline that could change the way we treat inflammatory skin disorders.[2] A modification of the 17α position of the steroid nucleus resulted in a molecule that retained the effect on anti-inflammatory targets while having minimal impact on the expression of other known target genes responsible for the side effects. The properties of GW870086 were compared to fluticasone propionate (FP) using a range of model systems, including extensive gene expression profiling. Murine models of irritant-induced contact dermatitis showed promising results. If the same efficacy and safety profiles can be demonstrated on humans as well, it may fulfill our long quest for a safe topical steroid.

Special thanks to Dr Yun of University of Akron and Dr Uings of GSK and their respective teams for the details.

References:

1. Shah, Parth N, and Yang H Yun. "Cellular interactions with biodegradable polyurethanes formulated from L-tyrosine." Journal of Biomaterials Applications (2011).

2. Uings, IJ et al. "Discovery of GW870086: A potent anti‐inflammatory steroid with a unique pharmacological profile." British journal of pharmacology (2013).

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The Angry Back

Have you had patients with an ‘Angry Back’ showing positive reaction to several patch test allergens? Or do you have stasis dermatitis patients sensitive to several allergens?[1] 
English: 2+ patch test reaction
English: 2+ patch test reaction (Photo credit: Wikipedia)

"Polysensitisation" (PS) is usually defined as contact sensitisation to 3 or more unrelated haptens of the baseline patch test series. It is debatable whether the PS phenotype represents a distinct genotype or a natural staggered progression from a uni to oligo to polysensitisation process. Statistical modelling for identifying risk factors for this ill defined PS phenomena to 3 or more ‘unrelated’ haptens is difficult. Bivariate analysis and logical regression models were unsatisfactory.

This recent article [2] in BJD explores the concept of Polysensitisation (PS) in contact dermatitis using an interesting and novel methodology using a colossal central European dataset of about 140,000 patch test results. They have used a negative binomial hurdle regression method for count data to independently estimate risk to be sensitised at all and the risk of having several contact allergies, i.e., to be polysensitised.

The axillae and the feet were found to be strong PS risk factors along with increasing age and female sex. In comparison, atopic eczema and occupational dermatitis were less important risk factors.

The size of their dataset and the novel methodology makes this the most authoritative study of this unique phenomenon.

Special thanks to Dr. Wolfgang Uter and the rest of the team for the details.

References:

1. OD - CoD - http://gulfdoctor.net/acd/ (Object Database for Contact Dermatitis)

2. Schwitulla, J et al. "Risk factors of polysensitisation to contact allergens." British Journal of Dermatology (2013). http://onlinelibrary.wiley.com/doi/10.1111/bjd.12423/abstract

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About Me

As a Dermatologist and Informatician my research mainly involves application of bioinformatics techniques and tools in dermatological conditions. However my research interests are varied and I have publications in areas ranging from artificial intelligence, sequence analysis, systems biology, ontology development, microarray analysis, immunology, computational biology and clinical dermatology. I am also interested in eHealth, Health Informatics and Health Policy.

Address

Bell Raj Eapen
Hamilton, ON
Canada