15025 Correlation of in vitro gene expression analysis with in vivo efficacy

Abstract

The objective of this research was to conduct in vitro gene expression testing of a plant-derived skin lipid mimetic (SLM) [INCI Jojoba Oil/Macadamia Seed Oil Esters (and) Squalene (and) Phytosteryl Macadamiate (and) Phytosterols (and) Tocopherol] and determine if these results correlate with randomized, double-blind, vehicle-controlled in vivo efficacy studies. Gene expression testing of 3% SLM in a simple oil in water (o/w) emulsion produced the following statistically significant gene expression changes over the vehicle: down regulation of MMP, EDN1, ICAM1, CXCL8/IL8, IL10, IL1B, PTGS2, and TLR2. Literature shows the following associations 1) MMP with collagen degradation. Down-regulation may help to increase elasticity and reduce wrinkle-related signs of aging. 2) CXCL8/IL8, IL10, IL1B, PTGS2, and TLR2 with an inflammatory response/barrier disruption. Down-regulation may reduce inflammation and barrier disruption. Three small IRB-approved studies were carried out on an o/w emulsion containing 3% SLM to obtain efficacy data. In study 1, SLM produced statistically significant (P < .001) increases in skin elasticity compared with the vehicle, after one week of use on photoaged skin (15%, n = 13). In study 2, SLM produced statistically significant (P < .001) increases in barrier recovery of delipidized skin (using acetone) compared with the vehicle, 60 minutes after one application (63%, n = 15). In study 3 SLM produced statistically significant (P < .001) increases in skin barrier function compared with 3% petrolatum, after two weeks of twice daily applications and after a one week regression (29% and 19%, respectively, n = 18). These studies demonstrate the correlation between in vitro gene expression data and in vivo efficacy.