Ciprofloxacin-Loaded Keratin Hydrogels PreventPseudomonas aeruginosaInfection and Support Healing in a Porcine Full-Thickness Excisional Wound

Abstract

Objective: Cutaneous wound infection can lead to impaired healing, multiple surgical procedures, and increased hospitalization time. We tested the effectiveness of keratin-based hydrogels (termed ''keratose'') loaded with ciprofloxacin to inhibit infection and support healing when topically administered to porcine excision wounds infected with Pseudomonas aeruginosa. Approach: Using a porcine excisional wound model, 10 mm full-thickness wounds were inoculated with 10 6 colony-forming units of P. aeruginosa and treated on days 1 and 3 postinoculation with ciprofloxacin-loaded keratose hydrogels. Bacteria enumeration and wound healing were assessed on days 3, 7, and 11 postinjury. Results: Ciprofloxacin-loaded keratose hydrogels reduced the amount of P. aeruginosa in the wound bed by 99.9% compared with untreated wounds on days 3, 7, and 11 postinjury. Ciprofloxacin-loaded keratose hydrogels displayed decreased wound contraction and reepithelialization at day 7 postinjury. By day 11, wounds treated with ciprofloxacin-keratose hydrogels contained collagen-rich granulation tissue and myofibroblasts. Wounds treated with ciprofloxacin-loaded keratose hydrogels exhibited a transient increase in macrophages in the wound bed at day 7 postinjury that subsided by day 11. Innovation: Current therapies for wound infection include systemic antibiotics, which could lead to antibiotic resistance, and topical antimicrobial treatments, which require multiple applications and can delay healing. Here, we show that ciprofloxacin-loaded keratose hydrogels inhibit cutaneous wound infection without interfering with key aspects of the healing process including granulation tissue deposition and remodeling. Conclusions: Ciprofloxacin-loaded keratose hydrogels have the potential to serve as a point-of-injury antibiotic therapy that prevents infection and supports healing following cutaneous injury.

Ciprofloxacin‐loaded keratin hydrogels reduce infection and support healing in a porcine partial‐thickness thermal burn

“…We and others have previously inoculated porcine excisional wounds to test antimicrobial therapies . However, excisional wounds lack the avascular eschar of burn wounds that provides a microenvironment conducive for bacterial growth and colonization .…”

“…Ciprofloxacin‐loaded keratin gels were prepared as described previously . Briefly, keratin was obtained by oxidative extraction of human hair and purified by KeraNetics, LLC using a patented and controlled manufacturing process .…”

“…Chromogenic IHC was performed using antibodies to α‐smooth muscle actin (Abcam, ab7817, mouse monoclonal, 1:100 dilution in 3% horse serum) and macrophages (MAC387, Abcam, ab22506, mouse monoclonal, 1:100 dilution in 3% horse serum) as described previously . For α‐smooth muscle actin‐stained sections, images spanning the entire wound bed were obtained using an Axio Scan slide scanner (ZEISS, Oberkochen, Germany).…”

“…One potential solution is the topical delivery of antimicrobials from biocompatible carriers such as keratin . Keratins are filamentous proteins from human hair that can be extracted via oxidative techniques .…”

“…These hydrogels have previously been shown to support the slow‐release of several small molecules including the antibiotic ciprofloxacin through mechanisms involving gel degradation as opposed to simple diffusion . Ciprofloxacin‐loaded keratin gels exhibit sustained antimicrobial activity against S. aureus in vitro and P. aeruginosa both in vitro and in vivo . In the studies presented herein, we test the ability of ciprofloxacin‐loaded keratin hydrogels to prevent P. aeruginosa and S. aureus infection in a porcine, partial‐thickness burn model.…”