JOURNAL OF COSMETIC SCIENCE 40 skin improvement to fi ght skin aging. This discovery and newly developed methods and equipment offer new opportunities for clinical and cosmetic applications such as strength- ening several skin structural interfaces. We demonstrated that K. senegalensis bark extract is an interesting active ingredient to boost collagen XVIII synthesis, thus leading to cosmetic applications targeting improvements of skin surface heterogeneity (pores and microrelief), wrinkles (data not showed) and skin elasticity. These fi ndings allow us to claim the discovery of the “skin matrix lifter.” Figure 8. Skin cheek curvature improvement (surface heterogeneity). Signifi cant improvement observed with Khaya senegelensis bark extract treatment versus placebo. Percentage versus baseline on 24 volunteers (53–65 years old). Statistical signifi cance assessed running Student’s t test or Wilcoxon test versus baseline, and Student’s t test or Mann–Whitney test versus placebo test, *p 0.05, **p 0.01. Figure 7. Skin immediate elasticity R7 (Ur/Uf) improvement. Signifi cant improvement is observed with Khaya senegelensis bark extract treatment versus placebo. Percentage versus baseline on 25 volunteers (53–65 years old). Statistical signifi cance assessed running Student’s t test or Wilcoxon test, *p 0.05, **p 0.01, ***p 0.001.

COLLAGEN XVIII: A KEY INTERFACIAL COMPONENT 41 REFERENCES (1) L. Seppinen and T. Pihlajaniemi, The multiple functions of collagen XVIII in development and disease, Matrix Bio., 30, 83–92 (2011). (2) A. Utriainen, R. Sormunen, M. Kettunen, L. Carvalhaes, E. Sajanti, L. Eklund, R. Kauppinen, G. Kitten, and T. Pihlajaniemi, Structurally altered basement membranes and hydrocephalus in a type XVIII collagen defi cient mouse line, Hum Mol Genet., 13(18), 2089–2099 (2004). (3) R. Bazin and E. Doublet, Skin Aging Atlas: Volume 1 Caucasian Type. (2007).