Bioresponsive dextrin-rhEGF conjugates: in vitro evaluation in models relevant to its proposed use as a treatment for chronic wounds.

Abstract

We recently developed a bioresponsive dextrin-recombinant human epidermal growth factor (rhEGF) conjugate as a polymer therapeutic with potential for use in the promotion of tissue repair. The aim of these studies was to use patient-derived wound fluid and fibroblasts to evaluate its potential for further development as a treatment for chronic wounds, such as venous leg ulceration, a growing clinical challenge in the aging population. First, the levels of EGF (ELISA assay), alpha-amylase and elastase (enzyme assays) were measured in patient-derived acute and chronic wound fluid. EGF was detected in acute, but not in chronic wound fluid. alpha-Amylase concentrations were higher in acute (188 IU/L), compared to chronic wound fluid (52 IU/L), but both were in the range of human serum levels. Although elastase was present in chronic wound fluid (2.1 +/- 1.2 RFU/min), none was detected in acute wound fluid. Dextrin-rhEGF incubation in chronic wound fluid led to endogenous alpha-amylase-mediated release of rhEGF (ELISA) that was maximal at 48 h. When the migration of HaCaT keratinocytes and of human fibroblasts (isolated from patient-matched, normal skin and chronic dermal wounds) was studied in vitro using the scratch wound assay, enhanced cell migration was observed in response to both free rhEGF and alpha-amylase-activated dextrin-rhEGF conjugate compared to controls. In addition, fibroblasts displayed increased proliferation (normal dermal fibroblasts approximately 160%; chronic wound fibroblasts approximately 140%) following incubation (72 h) with dextrin-rhEGF that had been exposed to physiological levels of alpha-amylase (93 IU/L). These results suggest further preclinical in vivo evaluation of dextrin-rhEGF is warranted to determine whether conjugate pharmacokinetics and rhEGF liberation into such a complex and aggressive environment can still lead to bioactivity.

• Authors: Joseph Hardwicke, Ryan Moseley, Phil Stephens, Keith Harding, Ruth Duncan, David W Thomas
• Journal: Molecular pharmaceutics (Mol Pharm) Vol. 7 Issue 3 Pg. 699-707 (Jun 07 2010) ISSN: 1543-8392 [Electronic] United States
• PMID: 20166755 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Dextrins
• Recombinant Proteins
• Epidermal Growth Factor
• alpha-Amylases

Topics

• Cell Line
• Cell Movement (drug effects)
• Cell Proliferation (drug effects)
• Cells, Cultured
• Dextrins (chemistry)
• Enzyme-Linked Immunosorbent Assay
• Epidermal Growth Factor (chemistry, metabolism, pharmacology, therapeutic use)
• Fibroblasts (cytology, drug effects)
• Humans
• Keratinocytes (cytology, drug effects)
• Recombinant Proteins (chemistry, metabolism, pharmacology, therapeutic use)
• Wound Healing (drug effects)
• alpha-Amylases (metabolism)