The dermal-epidermal junction (DEJ) is a complex structure that plays a critical role in maintaining the structural and mechanical properties of the skin. Intrinsic and extrinsic aging are associated with flattening of the DEJ and decreased expression of some of its constituent proteins. These changes are involved in aging skin that becomes brittle and in wound healing. L(+)-Rhamnose Monohydrate, a natural monosaccharide with cell-promoting and anti-inflammatory properties, targets lectin-expressing cells recognized by L(+)-Rhamnose Monohydrate, such as keratinocytes and papillary Fibroblasts. Since keratinocytes and fibroblasts are involved in the formation of DEJ, we investigated the effect of L(+)-Rhamnose Monohydrate on the expression of DEJ components. L-rhamnose has very poor skin absorption, and we attached it to methylsilanetriol (MTS), a carrier molecule that confers cell-promoting and connective tissue-restructuring properties.
L(+)-Rhamnose Monohydrate targets DEJ
Localization and expression of four important DEJ components were determined using immunofluorescence:
— Laminin 5 (Laminin5) is a protein produced by keratinocytes that binds basal keratinocyte plasma membrane and Lamina Densa type VII collagen. L-rhamnose alone had no significant effect on this protein, but rhamnose-silanol (R-S) enhanced the protein expression (data: 1% R-S increased by 18%, 5% R-S increased by 18%).
– Perlecan is a ubiquitous heparan sulfate proteoglycan present in all basement membranes, linking nidogen and type IV collagen. 5% R-S significantly increased the expression of perlecan (+25%).
—Type IV collagen (IV Collagen), one of the most abundant collagen glycoproteins in the basement membrane, is an important component of the dense layer. L-rhamnose alone induces moderate collagen type IV expression (+17%), while the same concentration of R-S greatly enhances collagen IV expression (+64%), and expression increases at low concentrations of R-S (1%) Already very noticeable (+41%).
– Type VII Collagen, a large protein located beneath the compact layer, is considered a major component of the anchoring fibril, whose flexibility is necessary to maintain the epidermis-dermis bond. L-rhamnose can boost collagen VII expression (25%), and this boost is synergistic when combined with silanols (58%).
Afterwards, it was further proved by immunofluorescence analysis carried out in human extracorporeal skin that L-rhamnose was combined with MTS to enhance bioavailability and efficacy. In this experiment, L(+)-Rhamnose Monohydrate had no apparent effect. Notably, MTS alone was able to promote type VII collagen expression. The R-S combination clearly promotes type VII collagen expression and migration to the DEJ, suggesting that MTS facilitates the delivery of L-rhamnose to dermal fibroblasts responsible for the synthesis of type VII collagen (and many other DEJ components).
The role of rhamnose silanol in the multiple layers of the skin
Aging affects all skin layers: the epidermis becomes thinner and less regenerative, and the extracellular matrix (ECM) of the dermis decreases and deteriorates. We therefore measured other parameters to demonstrate the efficacy of R-S on the epidermis and dermis:
– Ki67 nucleoprotein, a marker protein of epidermal cell cycle.
— Collagen type I, the main collagen in the dermis, the decline of which is a sign of aging. As previously shown, R-S was able to promote the expression of DEJ components (collagen type IV, laminin 5). Furthermore, we found that R-S promoted keratinocyte proliferation (Ki67) and expression of type I collagen in the dermis.