1. In vitro assessment of shampoos eye stinging potential using Transient Receptor Potential Vanilloid Type 1 (TRPV1)
Frédéric AMARAL
L’Oréal Research and Innovation , Aulnay, France

2. Presentation Outline Role of TRPV1 in nociception
Objectives of the study/experimental design
Results
Conclusions and next steps

3. Role of TRPV1 in nociception (1)
Receptor type: calcium permeable ion channel belonging to the TRP (Transient Receptor Potential) family
Location: C-fibers, CNS but also in skin, cornea and mucosal tissue
Activation: heat, acidic conditions, Capsaicin (CP)
calcium flux from extracellular sources
Release of neurotransmiters, neuropeptides
induction of pain, burning, pruritus

4. Role of TRPV1 in nociception (2)
Need for an in vitro assay for identifying the stinging potential of personal care products (ingredients and formulae)

5. Objectives of the Study/experimental design
To demonstrate the PoC with the « Nociocular » in vitro assay (based on SH-SY5Y overexpressing TRPV1)
Collaboration with the University of Stockholm (A Forsby)
Read out of the assay: calcium influx (fura2-AM)
Test articles used:
TRPV1 agonist: capsaicine (CP) for sensitivity
TRPV1 antagonist: capsazepine (CPZ) for specificity
A selection of 10 coded shampoos (adults and children/baby)

6. Results: in vitro assay data
3 categories of profiles have been identified
Case C
induction of Ca2+ flux
No impact of CPZ
TRPV1-mediated effect?
Case A
No induction of Ca2+ flux
Case B
induction of Ca2+ flux
Decreased response with CPZ
TRPV1-mediated effect

7. Results: in vitro/in vivo correlation
Good correlation, especially for extreme classes
Good trend for the moderate class except for formula G

8. Conclusions We have demontrated that: Next steps:
The « Nociocular » assay could be used to evaluate eye stinging personal care products
The assay was applicable to complex water-soluble formula
For some formulae, the response was TRPV1-mediated
The in vitro responses correlated well with clinical data
Next steps:
To evaluate a more diverse set of formulae and ingredients
To confirm the robustness of the assay
To refine the discomfort classes proposed
To develop a model for non water-soluble formulae
To sick for additional assays to get a better understanding of the responses observed

9. University of Stockholm
Acknowledgments
L’OREAL
Linda Bourouf
Reine Note
Thomas Delanne
Gladys Ouédraogo
Sophie Loisel-Joubert
José Cotovio
Jean-Roch Meunier
University of Stockholm
Hanegraaf Maaike
Anna Forsby