Extracts from the Lectures of the 32nd Nordic Congress of Dermato-Venereology, Tampere, Finland
Keynote Lecture by Howard Maibach
Clinical Challenge in Percutaneous Absorption
Professor Howard Maibach from University of California, San
Francisco is one of the leading ?gures in dermatology in the
world. His research in the ?elds of contact dermatitis, dermatotoxicology and dermatopharmacology has been groundbreaking. He has published over 1,200 refereed articles and
over 200 textbooks. His articles have been cited over 29,000
times. Professor Maibach has given postdoctoral training in
his laboratory in San Francisco for several Nordic dermatologists, including Jan Wahlberg, Klaus Andersen, Arto Lahti,
Kaija Lammintausta and Peter Andersen.
His talk in Nordic Dermatology Congress was entitled “Clinical
Challenges In Percutaneous Absorption”, a topic that he has been
working on for over 50 years. In his talk he described 15 determining factors for percutaneous absorption, related to local
skin and systemic absorption of topically applied substances.
These factors were (i) release from vehicle, (ii) kinetics of skin
penetration, (iii) excretion kinetics, (iv) tissue disposition, (v)
substantivity to skin, (vi) wash effects, (vii) rub effects, (viii)
effect of clothing, (ix) exfoliation, (x) volatility, (xi) binding
to skin layers, (xii) appendage effects, (xiii) lateral spread,
(xiv) vascular perfusion and (xv) cutaneous metabolism. The
talk highlighted the most important function of skin, acting
as barrier between outside world and living body. Several
conditions compromise this function and may cause several
diseases from eczema to systemic toxicity and anaphylaxis.
Professor Maibach continues his research work in his laboratory and clinic and travels globally to give expert advice
and lectures to various audiences, from dermatologists and
toxicologists to government departments and international
societies and expert groups.
ANTTI LAUERMA
E-mail: antti.lauerma@hus.?
Leena Koulu and Howard Maibach at the Congress dinner.
124
Nordic Dermato-Venereological Congress, Tampere
Psoriasis and Comorbidities
Plenary Lecture by Jonathan Barker:
From Genetic Discovery to Clinical Utility
Historically, attempts to identify susceptibility genes in common, complex diseases such as psoriasis have relied on a candidate gene approach. In general these have been unsuccessful in
great part due to inadequate knowledge of disease pathogenetic
mechanisms and small sample sizes. The explosion of genetic
information created by the human genome mapping project
and subsequent initiatives has led to development of methodologies that permit in a robust way detection of common genetic variants predisposing to many diseases. Such techniques
have been applied with great success to psoriasis. These studies
reveal multiple candidate genetic loci which cluster around
speci?c mechanisms. These are: epidermal barrier candidate =
LCE3, innate immunity (e.g. IFIH1, TYK2, TRAF3IP2) , antigen
processing and presentation (ERAP-1 and HLA-C) and T-cell
differentiation down IL23/IL17 pathway (IL23R, IL12B).
Interestingly there is overlap with other immune-mediated
in?ammatory disorders including in?ammatory bowel disease
and ankylosing spondylitis, and intriguing parallels with atopic dermatitis, another in?ammatory skin disorder in which
barrier defects and immune dysregulation are also important.
There are also key differences with certain phenotypic variants
of psoriasis. Pustular forms appear to have a different genetic
background. In some patients this relates to mutations in an
interleukin-1 family member termed IL36RN, which is not
observed in plaque forms of the disease. These ?ndings are
also consistent with a number of clinical observations, including the association between interferon- and ?are of psoriasis
and also explain why targeted therapies inhibiting TNF and
IL12/23 and IL17 are so effective. They provide important data
on which to base future drug design, including small molecules.
Currently it is unclear why there is variation in response of
patients to speci?c drugs. Pharmacology is likely to play a key
role, for example development of anti-drug antibodies. However, genetic heterogeneity is also likely to be involved raising
the potential of genetic testing as a co-diagnostic with use of
Fig. 1. Pathogenetic mechanisms in psoriasis: A genetic’s viewpoint.
Forum for Nord Derm Ven 2013, Vol. 18, No. 4