When asked about which factors contribute to the skin barrier defect seen in AD, the proportion of learners who identified the correct answer (deficits in filaggrin
) rose from about 22% (pretest) to nearly 75% after exposure to the education.
Mutations in filaggrin
appear to play a role in the development of AD, but a significant proportion of people with AD do not have evidence of filaggrin
mutations, and about 40% of people with defects never develop AD, she noted.
The role of the skin barrier was also proved by a study conducted by Hotze et al., in which 20 patients with atopic dermatitis were treated with omalizumab, and there was a better treatment response in the subgroup with no filaggrin
mutation and with higher serum levels of phosphatidylcholines (18).
In particular, mutations in the genes encoding filaggrin
, the serine peptidase inhibitor Kazal-type 5, and corneodesmosin, which are three components of the epithelial barrier, are associated with atopic dermatitis.
Since the level of filaggrin
mRNA decreases with age, increasing the expression of filaggrin
might help reduce dryness and itch, which are characteristic of aged skin.
There are prominent roles of genetic variations and mutations (predominantly filaggrin
mutations) and impaired barrier function (e.g., aberrancies in epidermal pH buffering capabilities), which may promote bacterial biofilms and create an environment favoring sensitization (13,22,23).
For dermatophytes, including those causing tinea corporis, amino acids are regarded as a source for growth.16 Under in vivo condition, dermatophytes secret several types of endopeptidase and exopeptidase in the presence of keratin as a sole nitrogen source.17 These enzymes digest proteins into peptides and free amino acids to be used as nutrients by fungi.18 One of these proteins is filaggrin
that acts in assembling of keratin bundles.
Vitamin D is thought to be involved in the formation of the stratum corneum barrier and in the synthesis of proteins such as filaggrin
, via the regulation of keratinocyte proliferation and differentiation.
A case-control study from Taipei, Taiwan, on the effects of phthalate exposure and filaggrin
gene variants on atopic dermatitis showed that children with specific filaggrin
genotypes had higher urinary concentrations of phthalates, suggesting that such genotypes may increase skin permeability and so may lead to the higher absorption of phthalates and result in increased susceptibility to atopic dermatitis in such children (Wang and Karmaus 2015) In terms of mechanisms, phthalates might impair the epidermal barrier development processes In addition, skin barrier defects caused by filaggrin
gene mutations may allow allergens or irritants to penetrate the epidermis and to interact with antigen-presenting cells, phenomena which lead to the development of atopic dermatitis (Osawa et al .
plays a crucial role in maintenance of the skin barrier.
Simon et al., "High levels of cytokeratin 19 fragments but no evidence of cytokeratins 1,2, 10/11, 14 or filaggrin
in the serum of squamous cell lung carcinoma patients," Tumour Biology, vol.
Gonzalez, "Noninvasive detection of filaggrin
molecules by raman spectroscopy," in Filaggrin