Downing, "The Role of the Corneocyte
Lipid Envelopes in Cohesion of the Stratum Corneum," Journal of Investigative Dermatology, vol.
Since KLKs process prointerleukin- (IL-) 1[alpha] and IL-1[beta] that are abundantly stored in the corneocytes
to active forms, this enhanced KLK activity leads to skin inflammation .
While doing research at the University of Toronto, we hypothesized that cerumen impaction is not a result of overproduction in the ceruminous glands, but a failure of individual corneocytes
in the stratum corneum to separate.
In essence, most products work on the principle of trapping or concentrating water content within the epidermis, replenishing corneocytes
with water, causing them to swell (6) (improving their apposition) and replacing depleted NMFs to improve waterproofing and restore the skin barrier function to the epidermis.
The SC consists of the ordered association of dead corneocytes
exerting a prominent barrier function leading to partial protection from ultraviolet (UV) light, microorganisms, and various toxic xenobiotics.
Sebum may serve as nutrition to facilitate biota growth and metabolism, thereby enhancing proliferation of keratinocytes and their transformation to comeocytes as well as serve as a glue cementing corneocytes
to form flakes.
Filaggrin is the key protein that causes aggregation of keratin filaments in the corneocyte
Using modern confocal microscopy and both 2-D and 3-D fluorescence microscopy with corrected values for cellular swelling, it was found that corneocyte
arrangement showed partial column-like alignments, but less than that assumed in earlier structural models.
Although some compounds such as ethanol and oleic acid were shown to penetrate corneocyte
structure, a literature search reveals no clear evidence for penetration of solid particles into the corneocyte
It was first proposed 3 decades ago and now is widely appreciated that the structure of the stratum corneum is analogous to that of a brick wall, with corneocyte
"bricks" held in place by the extracellular matrix "mortar" (1-3) The stratum corneum barrier relies predominantly on the extracellular matrix, where lamellar bilayers block the outflow of water into the environment and prevent the ingress of toxic substances, allergens, and microbial pathogens into the body.
It reinforces the corneocyte
envelope (synthesis of involucrin, transglutaminase and tight junctions), and the intercellular cement by lipid production (ceramides and cholesterol) ensuring the skin barrier function.
Moreover, after one month of continuous clinical use, stratum corneum removal and corneocyte