In the United States (U.S.), approximately 50 percent of all major hospitalization complications involve nosocomial infections. This represents over two million patients at a cost in excess of $4.5 billion per year. The widespread prophylactic and acute use (and misuse) of antibiotics to combat infection contributes to increased numbers of drug resistant bacteria. Thus, there is a continuing need to develop new antibiotics, but these new antibiotics also quickly loose their efficacy as new resistant strains of bacteria arise. The applicants believe the answer is to utilize therapeutics that can stimulate natural cell-mediated killing of bacteria or stimulate the recruitment of antimicrobial cells to the site of infection. The investigators have discovered a novel 15-amino acid peptide that is released at the site of tissue injury by thrombin cleavage of specific cell surface receptors and is selectively chemotactic for neutrophils. This human Neutrophil Targeting Peptide (hNTP15) may therefore target neutrophils to the site of injury where if needed they can be activated to eliminate microbial infestations. Preliminary data show that the synthetic hNTP15 peptide is nearly as chemotactic as interleukin 8 (IL-8) or thrombin and that there appears to be a neutrophil-specific cell surface receptor to which hNTP15 binds. In the proposed Phase I studies the applicants will: (1) determine the chemotactic efficacy of highly-purified Good Laboratory Practice (GLP) synthesized hNTP15 in vitro using Modified Boyden Chambers and fluorescent chemotactic assays and in animal wound models using implanted polyvinyl alcohol (PVA) sponges and full-thickness excisional wounds; (2) determine if treatment of wounds in animal models helps reduce infection when live Pseudomonas are added to the wounds; and (3) determine if hNTP15 has major safety or stability issues that would prevent it from moving forward as a drug candidate. For these studies intravenous (I.V.) and Intraperitoneal (I.P.) bolus injections into mice will be conducted under GLP conditions (Stillmeadow Laboratories) and stability testing will be assessed using established high-performance liquid chromatography (HPLC) and activity measurements. If hNTP15 shows potential efficacy in the animal models, the applicants will move forward with Phase II development of a commercial formulation for topical application to reduce infection in acute or chronic wounds to be used alone or as an adjunct therapy to existing antibiotics.
