Thierry Hoc - I started my career studying the plasticity of metals and how dislocations could brittle materials.  Lyon being a region where there is intensive research on living organisms, when I arrived at the Ecole Centrale de Lyon in 2009, I focused on themes related to bio-engineering with a mechanic’s approach. Our first works showed that bone balance was governed by the biochemical environment of the bone but also by the mechanical strain undergone by cells.
Our experiments revealed for example, that cells had low sensitivity to compression while shear improved their development. This mechanical environment is therefore crucial in the aging process of tissues leading to specific architectures. Some connective tissue create, for example, some microstructures with very conveniently oriented collagen and elastin fibres to withstand the mechanical strain associated with the in vivo environment that one goes through every day. We observed from mechanical tests on collagen fibres, in the presence of elastin fibres, that the mechanical strength was fully linked to collagen fibres, while the tissue springback was linked to elastin fibres.
These works have direct applications in the treatment of bone disease (brittle bone disease, osteoporosis, osteoarthritis) in the treatment of parietal hernias but also in tissue engineering which requires better characterizing the environment of the cell. All this data is taken into account in skin cultures with the addition of mechanical strain. Skin is also an excellent marker of aging as Prof. Hassan Zahouani demonstrated. Tension lines at the skin surface reflect the mechanical behaviour and the morphology of more or less deep wrinkles. It is in this context that we use the skin as a laboratory for aging, and that we look if there are some existing correlations between the mechanical properties of bones and the morphology of the skin, in cases of osteoarthritis, is the skin more or less wrinkled, are tension lines different, has elastin gone...? A number of promising and open questions.
Premium Beauty News - Since 2012, you are in charge of the equipment of excellence for the engineering and aging of living tissues (ingénierie et vieillissement des tissus vivants or IVTV). Can you explain what this vast project, selected by the Ministry of Higher Education and Research, is about?
Thierry Hoc - The IVTV platform, located in the Ecole Centrale de Lyon and in the Health Cluster of St. Etienne is the only centre of its kind in Europe. It aggregates 14 research laboratories, two hospitals, nine private–sector companies, including four operating in cosmetics, around high-tech tools, coupling mechanics and multi-scale imaging to help characterize the chemical, mechanical, topographical properties of the different tissues (bone, teeth, cartilage, skin, ligaments, arteries, muscles...), to individually follow their aging and make correlations between observations performed. Skin being easily accessible, we are seeking to understand if its aging reflects the aging of other tissues. The platform was launched in December 2012, it offers training services and provision of equipment but also services. Exchanges between the 170 permanent members of the platform are frequent and the development of cross-functional skills is a priority.
Premium Beauty News - What will, the industry - including cosmetic manufacturers - be using the IVTV platform for and what are the current results?
Thierry Hoc - Operational studies have begun a few months ago; to date several oral presentations have been made, highlighting a great potential. For example, confocal microscopy enables to monitor how soft tissue composed of collagen and elastin respond when they are subjected to mechanical stress, how fibres react, how they redirect themselves. Raman spectroscopy helps monitor the penetration of actives at different depths; ultra-sound propagation speed measurements in tissues will enable to better characterize the skin according to its age. The field is vast and areas of application are dermatology, orthopedics and cardiovascular, but we always keeping a key thread on understanding, on the product/tissue interaction and with a partnership between the doctor/engineer and the biologist.
A visit of the IVTV laboratory is planned during the post IFSCC day, organized by the European Centre of Dermocosmetology (CED), on October 31, 2014.
Premium Beauty News - How do you think aging could be addressed in 20 or 30 years?
Thierry Hoc - to date scientific advances enable to reconstruct the skin, bones, arteries. I believe that in a near future, we could, maybe not make human beings bionic, but anticipate human tissue degradation and through cell therapy, overcome these unwanted changes in order to locally regenerate damaged tissues.