Peter Lersch

Bioactive tetrapeptide GEKG boosts extracellular matrix formation: in vitro and in vivo molecular and clinical proof

Abstract:  The ‘matrikine’ concept claims that processing of the precursors for collagen results in the formation of peptides such as KTTKS which in turn augments extracellular matrix (ECM) production. In the present study, we show the development of an anti‐ageing active from an in silico approach by molecular design resulting in the tetrapeptide GEKG derived from ECM proteins. The efficacy of the peptide to significantly induce collagen production of the protein level and mRNA level has been demonstrated in vitro in human dermal fibroblasts and in vivo in a double‐blind, randomized, placebo‐controlled study enroling 10 volunteers with an average age of 48.2 years. The effect of GEKG on facial wrinkles was studied in 30 volunteers using state of the art fringe projection, which allows determination of surface roughness in three‐dimensions. Here, only GEKG but not the placebo was able to significantly decrease skin roughness as a measure for wrinkles.

Facial skin-lightening benefits of the tetrapeptide Pro-Lys-Glu-Lys on subjects with skin types V–VI living in South Africa

Background  Irregular skin pigmentation may be a substantial contributor to the signs of aging and to a person’s lack of psychological well‐being. Although a large number of skin‐lightening agents are available, the opportunity exists to identify more efficacious agents, agents that target alternative biological mechanisms.

Topical ceramides neither enhance UVB‐induced apoptosis in normal human keratinocytes nor affect viability in UVB‐irradiated reconstructed human epidermis

Ceramides are the major lipid of lamellar sheets present in intercellular spaces of the stratum corneum contributing to epidermal barrier properties. Therefore, ceramides and their analogues have been studied for barrier enhancing and water‐holding properties for decades. In vitro studies have indicated cytotoxic potential for cell‐permeable ceramides thereby raising the question whether topical ceramide application might contribute to UVB‐induced apoptosis. Phytosphingosine, N‐hexanoyl‐phytosphingosine and N‐stearoylphytosphingosine (ceramide III) in concentrations ≤5 μm have been used for co‐stimulation with low (160 J/m2) or high (600 J/m2) UVB doses in subconfluent basal and confluent differentiating keratinocytes. Significantly, increased caspase‐3 activity was observed in basal keratinocytes irradiated with 600 J/m2 UVB and in differentiating keratinocytes with both UVB doses. Co‐stimulation with the named ceramides did not further increase (i) caspase‐3 activity and (ii) nucleosomal fragmentation in differentiating keratinocytes. Moreover, co‐stimulation with 1‐mm ceramides did not further affect viability/lactate dehydrogenase release in UVB‐irradiated reconstructed human epidermis corroborating the safety of these ceramides.