protegrin-1 and Burns

Antimicrobial peptides are naturally occurring cationic peptides. The first-line of defense in infected burns is the innate immune system, of which antimicrobial peptides are essential parts. To facilitate their topical use in infected partial-thickness burns, the efficacy of a mixture with fibrin glue in vitro and in vivo was tested.. After in vitro tests, 15 male Sprague-Dawley rats received partial-thickness burns. Afterwards, the wounds were infected with multiresistant Pseudomonas aeruginosa. The animals received PG-1 (100 microg/ml, n=5), fibrin glue (n=5), or a mixture of both (n=5) topically. The efficacy of the materials was previously proven by radial diffusion assay. After 24 h, the infected and burned skin was harvested and quantitative bacterial counts per gram of skin performed.. The biologic effect of the peptides was confirmed in vitro. The PG-1 and fibrin glue groups did not show significant differences in bacterial numbers, whereas the mixture group showed significant reduction in Pseudomonas in vivo (P<0.04 and P<0.01).. A mixture of an antimicrobial peptide and commercially available fibrin glue is capable of significantly reducing bacteria in infected partial thickness burns in vivo compared to controls.

Topics: Animals; Anti-Infective Agents; Antimicrobial Cationic Peptides; Burns; Colony Count, Microbial; Dose-Response Relationship, Drug; Drug Combinations; Drug Resistance, Multiple; Escherichia coli; Fibrin Tissue Adhesive; Male; Microbial Sensitivity Tests; Proteins; Pseudomonas Infections; Rats; Rats, Sprague-Dawley; Wound Infection

Infections with multidrug-resistant microorganisms (e.g. Pseudomonas aeruginosa and Staphylococcus aureus) cause immense complications in wound care and in the treatment of immunosuppressed patients. Like most antimicrobial peptides, histones are relatively small polycationic proteins located in each eukaryotic nucleus, which naturally supercoil DNA. The aim of this study was to investigate the in vitro and in vivo activity of histone H1.2 in infected burn wounds and its potential toxicity.. To characterize the antimicrobial properties of histone H1.2 against potential causative organisms of burn wound infections, the in vitro radial diffusion assay and modified NCCLS microbroth dilution MIC assay were carried out. Haemolytic and cytotoxic properties were determined in human red blood cells and primary human keratinocytes. In vivo antimicrobial activity was tested in an infected rat burn model with P. aeruginosa (ATCC 27853). All results were compared with the naturally occurring broad-spectrum antimicrobial peptide protegrin-1 and with antibiotics clinically used against the corresponding bacteria.. Human histone H1.2 exerted good antimicrobial activity against all tested microorganisms without significant haemolytic activity. Surprisingly, histone H1.2 showed cytotoxicity with an LD50 of 7.91 mg/L in primary human keratinocytes. The in vivo burn model data revealed a significant three-fold higher reduction in bacterial counts within 4 h compared with carrier control.. These findings indicate that histone H1.2 is a potential candidate for use as a local and, because of its low haemolytic activity, systemic antimicrobial agent. However, further investigations are needed to specify the cytotoxicity and the dose-response relationship for histone H1.2.

Topics: Animals; Antimicrobial Cationic Peptides; Bacteria; Burns; Cells, Cultured; Disease Models, Animal; Erythrocytes; Hemolysis; Histones; Humans; Keratinocytes; Microbial Sensitivity Tests; Proteins; Pseudomonas aeruginosa; Pseudomonas Infections; Rats; Skin; Toxicity Tests; Wound Infection

Septic complications and the emergence of drug-resistant microbes represent serious risks to patients. Recently, naturally occurring peptides have been discovered that possess potent and broad-spectrum antimicrobial activity. Protegrin-1 is particularly attractive for clinical use in human wounds because, unlike defensins, protegrin-1 retains broad antimicrobial and antifungal activity at physiologic salt concentration and in the presence of serum. The objective of this study was to examine the efficacy of protegrin-1 in killing multiple drug-resistant microbes isolated from human burn patients.. For thein vitroexperiment, bilayer radial diffusion was performed comparing standard antibiotics with protegrin-1 on multiple-drug-resistant microbial organisms isolated from infected burn wounds. In vivo, rats received a 20% total body surface area partial-thickness burn by immersion in 60 degrees C water for 20 secs followed by wound seeding with 106 colony forming units of Silvadene-resistant Pseudomonas aeruginosa.. University of Michigan research laboratory.. Adult, male Sprague-Dawley rats.. Rats were randomized into three groups: those receiving synthetic protegrin-1, acetic acid (carrier), or gentamicin (positive control). Protegrin-1 was administered by topical application or intradermal injection. Wound tissues were harvested aseptically at different time points for quantitative bacterial counts.. In vivo and in vitro experiments revealed rapid and significant decreases in bacterial counts for protegrin-1-treated groups compared with controls.. This study shows that protegrin-1 potentially may be used as an alternative or adjunct therapy to standard agents used to treat wound infections.

Topics: Administration, Topical; Analysis of Variance; Animals; Anti-Bacterial Agents; Antifungal Agents; Antimicrobial Cationic Peptides; Burns; Colony Count, Microbial; Dose-Response Relationship, Drug; Drug Resistance, Multiple; Humans; In Vitro Techniques; Injections, Intradermal; Male; Proteins; Pseudomonas aeruginosa; Rats; Rats, Sprague-Dawley; Time Factors; Wound Infection