The Influence of Chronic Wound Extracts on Inflammatory Cytokine and Histatin Stability

PLoS One. 2016 Mar 28;11(3):e0152613. doi: 10.1371/journal.pone.0152613. eCollection 2016.

Abstract

Chronic ulcers represent a major health burden in our society. Despite many available therapies, a large number of ulcers do not heal. Protein based therapies fail in part due to proteolytic activity in the chronic wound bed. The aim of this in vitro study was to determine whether typical inflammatory cytokines and human salivary histatins remain stable when incubated with chronic wound extracts. Furthermore we determined whether a short exposure of histatins or cytokines was sufficient to exert long term effects on fibroblast migration. Stability of human recombinant cytokines IL-6 and CXCL8, and histatin variants (Hst1, Hst2, cyclic Hst1, minimal active domain of Hst1) in the presence of chronic wound extracts isolated from non-healing ulcers, was monitored by capillary zone electrophoresis. Migration-stimulating activity was assessed using a dermal fibroblast wound healing scratch assay. Histatins and cytokines stayed stable in saline for > 24 h at 37°C, making them ideal as an off-the-shelf product. However, incubation with chronic wound extracts resulted in serious breakdown of Hst1 and Hst2 (~50% in 8 h) and to lesser extent cyclic Hst1 and the minimal active domain of Hst1 (~20% in 8 h). The cytokines IL-6 and CXCL8 were more stable in chronic wound extracts (~40% degradation in 96 h). An initial 8-hour pulse of histatins or cytokines during a 96-hour study period was sufficient to stimulate fibroblast migration equally well as a continuous 96-hour exposure, indicating that they may possibly be used as novel bioactive therapeutics, exerting their activity for up to four days after a single exposure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Movement / drug effects
  • Cells, Cultured
  • Chromatography, High Pressure Liquid
  • Cytokines / chemistry
  • Cytokines / metabolism*
  • Electrophoresis, Capillary
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Histatins / chemistry
  • Histatins / metabolism*
  • Humans
  • Interleukin-6 / chemistry
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Interleukin-8 / chemistry
  • Interleukin-8 / genetics
  • Interleukin-8 / metabolism
  • Leg Ulcer / metabolism
  • Leg Ulcer / pathology
  • Protein Stability
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / pharmacology

Substances

  • Cytokines
  • Histatins
  • Interleukin-6
  • Interleukin-8
  • Recombinant Proteins

Grants and funding

The study was funded primarily by Technologiestichting STW (NL), (http://www.stw.nl/, grant number 10695, MAB SR KN JGMB ECIV SG) with minor contribution (4%) by A Skin BV, The Netherlands (http://a-skin.nl/). SG is co-founder of A-Skin BV which is a VU university medical center start up company (SME) and was involved in study design, data collection and analysis, decision to publish, and preparation of the manuscript. The other funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.