Bioactive Low Molecular Weight Keratin Hydrolysates for Improving Skin Wound Healing.

Laura Olariu,Carmen Gaidau,Ioana-Rodica Stanculescu,Luiza Mariana Tanase,Cristina Tablet,Brindusa Georgiana Dumitriu,Maria Stanca,Manuela Diana Ene

doi:10.3390/polym14061125

Abstract

Keratin biomaterials with high molecular weights were intensively investigated but few are marketed due to complex methods of extraction and preparation and limited understanding of their influence on cells behavior. In this context the aim of this research was to elucidate decisive molecular factors for skin homeostasis restoration induced by two low molecular weight keratin hydrolysates extracted and conditioned through a simple and green method. Two keratin hydrolysates with molecular weights of 3758 and 12,400 Da were physico-chemically characterized and their structure was assessed by circular dichroism (CD) and FTIR spectroscopy in view of bioactive potential identification. Other investigations were focused on several molecular factors: α1, α2 and β1 integrin mediated signals, cell cycle progression in pro-inflammatory conditions (TNFα/LPS stimulated keratinocytes and fibroblasts) and ICAM-1/VCAM-1 inhibition in human vascular endothelial cells. Flow cytometry techniques demonstrated a distinctive pattern of efficacy: keratin hydrolysates over-expressed α1 and α2 subunits, responsible for tight bounds between fibroblasts and collagen or laminin 1; both actives stimulated the epidermal turn-over and inhibited VCAM over-expression in pro-inflammatory conditions associated with bacterial infections. Our results offer mechanistic insights in wound healing signaling factors modulated by the two low molecular weight keratin hydrolysates which still preserve bioactive secondary structure.

Highlights

Introduction iationsKeratin can be extracted from keratin-rich materials using chemical, physical or biological methods [1]
Keratin extracted from sheep wool or human hair showed a high potential for wound healing biomaterials design [37–39], but the methods for keratin solubilization are very sophisticated and the mechanisms of cellular response are not completely understood [26]
The present research proposes the keratin hydrolysates with low molecular weights as wound healing additive, prepared by complete solubilization of sheep wool and by enzymatic refinery of molecular weight with still preserved secondary structure and showing bioactivity in integrin signaling, cell cycle modulation and vascular-cell-adhesion molecules inhibition

Summary

Introduction

Keratin can be extracted from keratin-rich materials using chemical (reduction, oxidation, hydrolysis, sulphitolysis), physical (steam explosion, microwave irradiation) or biological methods [1]. The properties of keratin such as amino acid content, molecular weight, thermal behavior and bioactivity depend on the extraction and preparation methods [2,3]. Biomaterials prepared from keratin extracted from wool or human hair showed excellent properties regarding biocompatibility and cellular proliferation abilities. These properties make wool keratin an excellent material for tissue engineering and drug delivery systems [4]. A study on the anti-inflammatory ability of keratin extracted from human hair showed that it has a more pronounced anti-inflammatory effect on monocytic cell line, than collagen

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