620 JOURNAL OF COSMETIC SCIENCE
Hyaluronic acid production by human keratinocytes. Hyaluronic acid is a natural skin moisturizer
existing both in the dermis and around keratinocytes. It allows the transfer of nutrients,
vitamins, salts, and of immune cells into the epidermis. Human keratinocytes were
placed in contact with various concentrations of pKTSKS to assess its ability to induce the
production of hyaluronic acid. Hyaluronic acid production by keratinocytes thus increased
significantly in a dose-dependent manner by 33%–62% (Figure 7).
EFFECT OF PKTSKS ON DERMIS
Dermal matrix restructuring through protein synthesis. Pentapeptide pKTSKS was demonstrated
to trigger the production of dermal extracellular matrix proteins by fibroblasts. Thus,
collagen-I production is increased under conditions described above by 184%, collagen-IV
by 98% and fibronectin by 67% (Table II).
EFFECT OF PKTSKS ON INFLAMMATORY RESPONSE
In acne condition, proinflammatory cytokines are upregulated due to bacterial proliferation
and pore clogging. Although this inflammatory process is transitory, prolonged cytokines
production results in scarring.27 This led us to study the effect of pKTSKS on inflammatory
cytokines.
IL-6 production by human sebocytes and keratinocytes in presence of C. acnes. C. acnes can disturb
skin homeostasis and trigger proinflammatory mediators release from skin cells, such as
IL-6. Human sebocytes and keratinocytes were first treated with pKTSKS for 24 hours.
Table I
Effect of pKTSKS (9 ppm) Applied Onto the Surface of LSE Thickness of Stratum Corneum (n =4)
Stratum corneum thickness (µm) Variation (%)
Control 16 ± 5 Reference.
pKTSKS 9 ppm 45 ± 11 +186% p 0.01
0
1000
2000
3000
4000
5000
6000
7000
8000
Solvent control pKTSKS 6ppm pKTSKS 9ppm pKTSKS 12ppm
Kerag415nocyte treatment
Effect of pKTSKS on hyaluronic acid producg415on
Figure 7. Variation in hyaluronic acid production by human keratinocytes effect of pKTSKS (n =5).
Secretion (ng/106 keratinocytes) of hyaluronic acid in supernatants of keratinocytes treated with pKTSKS
(6 ppm, 9 ppm, 12 ppm).
ng/10^6cell

621 Pentapeptide to Control Acne
Media was removed and replaced with fresh media containing C. acnes +pKTSKS or
vehicle for 24 hours or 48 hours. Secreted IL-6 was measured from cell culture media.
Table III shows the strong increase of this cytokine by human skin cells in response to
C. acnes contact: ×8.5 for sebocytes and ×371 for keratinocytes which are more sensitive
than sebocytes. Pentapeptide pKTSKS decreases, with dose-dependency, IL-6 release by up
to 48% in sebocytes and by up to 89% in keratinocytes (all p 0.01 versus their respective
control).
IL1-Ra production by human keratinocytes. IL-1Ra (interleukin-1 receptor antagonist) is a
naturally produced cytokine antagonist to the proinflammatory cytokine IL-1a, also known
as the master-regulator of inflammatory response. IL1-Ra production by keratinocytes was
quantified in cell culture media of keratinocytes treated with either pKTSKS (6–12 ppm)
or its solvent (0.1% DMSO) for 3 days. Results showed that pentapeptide pKTSKS dose-
dependently stimulates the IL-1Ra release by 167% to 283% for 6–12 ppm respectively
(both p 0.01 versus control solvent Figure 8).
EVALUATION OF PKTSKS IN CLINICAL TESTS
In vitro findings demonstrated that pKTSKS enhances the production of dermal matrix
proteins and exhibits anti-inflammatory effects. We therefore decided to perform a clinical
study on volunteers with acne-prone skin and acne scars. We assessed pKTSKS efficacy
in vivo in three different parameters associated with acne: inflammatory marks, pockmarks,
Table II
Synthesis of Collagen-I, Collagen-IV, and Fibronectin, Effect of pKTSKS (n =5). Secretion of Collagen-I,
Collagen-IV, and Fibronectin in Supernatants of Fibroblasts Treated With 10 ppm pKTSKS for 3 Days.
Quantification was Performed by ELISA
Collagen-I
pg/106cells
Variation (%)Collagen- IV
pg/106cells
Variation (%)Fibronectin
ng/106cells
Variation
(%)
Solvent
Control
589.4 ± 32.7 Reference 687 ± 22 Reference 16,896 ± 1,030 Reference
pKTSKS
10ppm
1,676.9 ± 147.3 +184%
p 0.01
1,360 ± 203 +98%
p 0.01
28,234 ± 3,841 +67%
p 0.01
*No cell toxicity was observed
Table III
Variation in IL-6 Production by Human Sebocytes and Keratinocytes Effect of pKTSKS (n =3–6). IL-6
Secretion (pg/106 cells) Measured by ELISA in Supernatants of Sebocytes and Keratinocytes Treated With
C. acnes +/− pKTSKS
Sebocytes Keratinocytes
IL-6
(pg/106 cell.)
Variation (%)IL-6
(pg/106 cell.)
Variation (%)
Control without C. acnes 11 ± 2 Ref1. 4 ± 1 Ref1.
Control +C. acnes 94 ± 19 Ref2. (X8.5 vs ref1) 1,484 ± 102 Ref2. (X371 vs ref1)
pKTSKS 6 ppm +C. acnes 84 ± 15 −11% ns 415 ± 22 −72% p 0.01
pKTSKS 9 ppm +C. acnes 70 ± 12 −26% p 0.05 176 ± 16 −88% p 0.01
pKTSKS 12 ppm +C. acnes 49 ± 7 −48% p 0.01 165 ± 15 −89% p 0.01
*No cell toxicity was observed. (ns): non-significant