With the growing evidence of the detrimental impact of exposome including pollution, blue light and UV radiation (UV-R), on skin and hair, consumers are searching for the best items to protect themselves. The best practice to substantiate protection or soothing claims against exposome resides on standardized, robust, and scientifically validated methodologies. Forerunner in the cosmetic industry testing, CIDP has set-up a Controlled Pollution Exposure System (CPES) which, as his name states allows the controlled concentrations and flux, of defined pollutants whether particulate (ambient dust, indoor dust,vaporization, in terms of particulate matter, diesel) or gaseous (ozone) on the skin and hair (Curpen S. et al., 2020). This unique system allows the monitoring of the effect of air pollution on the skin and hair health.

Moreover, to evaluate the impact of blue light on the skin, CIDP had developed two monochromatic LEDs which emit at 412 nm (mimicking blue light from solar radiation) and 450 nm (mimicking blue light from electronic devices). The intensity and thus the dose of blue light the skin is being exposed to is controlled by means of a broadband thermopile detector (Francois-Newton et al., 2022; Campiche R. et al., 2020).
 

In vivo evaluation of blue light on volunteer’s forearms

Importantly, both systems (CPES and Blue light LEDs) can be used in vitro (on monolayer cell culture) (Francois-Newton et al., 2021), ex vivo (on human skin explants or hair swatches) or in vivo on healthy volunteers (Lutchmanen-Kolanthan V. et al., 2022).The two former models allow identification of the mode of action of the test product and the biochemical pathways being triggered or inhibited. These data serve as crucial information to design the clinical trial and evidenced the efficacy of the product. Protect ion against the pigmenting effect of exposome such as UV-R or Blue light can be assessed in human skin explants as well as in human volunteers. Interestingly, it is becoming more and more evident that depending on skin phototype, skin reaction to these exposome will differ. Indeed, our group as well as other research groups have shown that hyperpigmentation, induced by visible light and more particularly blue light, can mainly be observed in melano-competent individuals (Mandary M.B. et al., manuscript under review).
 

Ex vivo evaluation of blue light on human skin explants

Methodologies combining in vivo (application of product on human volunteers), and ex vivo (exposure of tape strips or hair strand) methodologies can also be proposed (Mandary M.B. et al., manuscript under review). With this combined methodology, we also pass the ethical review of exposing the face or head of volunteers to exposome as either tape strips collected from the forehead or hair strands collected are exposed to the exposome.
 

Ex vivo evaluation of cigarette smoke on natural hair strands

Quantitative and Qualitative data sets can be generated from the preclinical and clinical testing. In the skin, from superficial biomarkers such as Squalene and its oxidized form, protein carbonylation, catalase, Malondialdehyde (MDA) collected from either tape strips or swabbing to more in-depth epidermal/dermal biomarkers such as Matrix Metalloproteinases (MMPs), degraded collagen, filaggrin or thymidine dimers that can be evaluated from skin biopsy punches, scientific evidence of the product efficacy can be demonstrated.
 

Skin biopsy

Different biomarkers can also be evaluated in hair swatches after exposure to exposome, whether air pollutant or water pollutant. These biomarkers include tryptophan (the main amino acid present in hair cuticle) degradation, MDA, ceramides, free fatty acids and also the presence of heavy metals (obtained from either air or water pollution) which are detected by ICP-MS.

About CIDP

Established in 2004, CIDP is a pioneer in providing top-notch Research & Development activities. As a CRO offering a full suite of services to the cosmetics industry from preclinical and clinical development phases, biostatistics, data management, regulatory affairs and scientific and medical writing. To better serve its clients worldwide, CIDP has strategically implanted itself in Mauritius, Romania, India and Brazil, therefore enabling access to a wide panel of volunteers. CIDP assists in delivering innovative and tailor-made solutions to meet client needs. CIDP strives to deliver excellent service by investing in state-of-the art equipment, technologies, and continuous training for its teams. All its subsidiaries are ISO 9001:2015 certified and its Romanian centre, expert in photobiology studies, is CIR accredited. For more information, you can contact the CIDP team on info@cidp-cro.com or visit our website on http://www.cidp-cro.com/.