In vitro biological efficacyStudying the action of active ingredients through in vitro testing
In vitro tests are used to study the action mechanisms of active ingredients on biological systems and their release. They are essential for demonstrating the efficacy of active ingredients for cosmetic products, dietary supplements and medicines.
In vitro tests use matrices to model biological systems, and techniques to measure efficacy using histology, molecular biology, and genomics.
Modeling biological systems
In vitro tests are based on a wide range of biological media and models, from in tubo models – used for example to measure the ability to neutralize free radicals, to living models such as cell cultures, reconstructed tissues, and isolated organs (hair follicles, skin explants, etc.).
Innovative active ingredients can be developed from these models. In cosmetics for example, the cultivation of senescent fibroblasts from the dermis, and the study of biochemical messages they send to surrounding young cells, helped Seppic understand the mechanism of contagious cell ageing, and highlight the efficacy of the red algae extract Aspar'Age™. The biochemical messages secreted by senescent fibroblasts trigger the aging process in the surrounding young cells, and the addition of Aspar'Age™ to the culture medium stops the spread of aging.
In the field of dietary supplements, in vitro models of inflammation in keratinocytes and innovative keratinocytes-neurons 3D co-culture were used to investigate the soothing effect of different plant extracts and identify potential candidates for the development of a new ingredient. A nutraceutical active ingredient, Sepibliss™ was selected and developped after confirmation of its effects in vivo, after oral intake by sensitive skin women.
Expertise in cell culture and tissue engineering for different target organs: skin, bones, muscles, retina...
Techniques for measuring effects on biological models
Measuring the effects on biological models, from genes to tissue functions, requires prowess in a variety of techniques. Molecular biology makes it possible to assess the effects on gene expression. With biochemical analyses, one can monitor protein production and enzyme activities. Tissue histology, combined with various imaging procedures such as immunofluorescence and immunohistochemistry, or more simply, specific staining techniques, provides a means to locate the compounds studied, and verify tissue integrity.
For example, a battery of in vitro models was conducted to study the influence of a titrated extract of Centella asiatica, TECA™, on the skin repair process. The tests included keratinocyte-fibroblast co-cultures, endothelial cells, collagen lattices associated with different biochemical analyses such as ELISA and Western Blot tests, and spectrocolorimetric and fluorescence measurements. The results showed a complete mechanism of action combining a soothing and protective effect on the epidermis with an acceleration of tissue reconstruction from the dermis.