A biophysically-defined hyaluronic acid-based compound accelerates migration and stimulates the production of keratinocyte-derived neuromodulators

ABSTRACT Hyaluronic acid (HA) preparations are widely used in clinical practice and recent data suggest that commercially available HA-based compounds promote ulcer re-epithelialization and induce pain relief. However, the pathophysiological basis of these effects remains poorly understood. In the present study, we investigated the biophysical, biomolecular and functional properties of a HA preparation combined with a pool of collagen precursor synthetic aminoacids, namely l-proline, l-leucine, l-lysine and glycine (Aminogam？). Hydrodynamic characterization of Aminogam？ by size exclusion chromatography-triple detector array (SEC-TDA) revealed an average molecular weight in the range of 700–1700 kDa. Rheological measurements of the 1700kDa Mw lot showed a pseoudoplastic behaviour with a zero-shear viscosity (η0) equal to 90 ± 9 Pa？s at 25°C and 55 ± 6 Pa？s at 37°C. Automated time-lapse videomicroscopy studies in a fibroblast-free system demonstrated that 1% (v/v) Aminogam？ significantly reduced the healing time of wounded keratinocyte monolayers. In AKGOS assays, Aminogam？ stimulated cellular locomotion (chemokinesis) and directional migration (chemotaxis) of keratinocytes. Analysis of microarray data suggested that keratinocytes had a functional neuroendocrine machinery, and this was confirmed by testing the secretion of six neuroactive molecules by ELISA, namely α-MSH, β-endorphins, melatonin, substance P, cortisol, and neurotensin. Interestingly, Aminogam？ regulated the production of several neuropeptides, including β-endorphins. In conclusion, our data shed light on the epithelial-dependent mechanisms that underlie the efficacy of Aminogam？, particularly in reference to wound healing and nociception