Topical Treatment of Diabetic Wounds to Increase Dermal Microvascular Blood Flow

DESCRIPTION (provided by applicant): Project Summary/Abstract Diabetic foot ulcers (DFU) and the related excess morbidity and mortality as a consequence of foot problems in people with diabetes represent a major public health challenge. The cost for the tr eatment of DFU and amputation in US in 2001 was estimated to be around 11 billion dollars. Abnormal wound healing which is the major cause of these amputations is a complication of both, type I and type II diabetes. Nitric oxide (NO) gas has been shown to play a significant role in the promotion and regulation of diverse wound healing processes. NO has also been shown to have promise as an antimicrobial therapeutic and has broad range of effectiveness against human pathogens. Most current nitric oxide thera pies (other than inhalation therapies) involve systemic or topical treatments with drugs designed to stimulate inducible nitric oxide synthase (NOS) intracellularly. In addition to a role of endogenous NO in wound healing through NOS, improvement of wound healing following exogenous NO has also been reported, including direct application of NO gas or application of topical gels or creams that synthesize NO and other cytotoxic nitrogen oxide species (nitrous acid, NO2). However, of the dozen or more current and pending NO-based pharmaceutical clinical trials, none of the topical approaches utilize an exogenous NO producing gel and thus rely on NOS pathways to generate minute amounts of NO locally. The direct delivery of more therapeutically relevant doses of NO gas for topical/dermal applications has been accomplished, although the method is complicated by NO's instability in air and difficulty to produce in a clinical setting. A more rational NO-based wound healing treatment would be convenient and safe to ap ply in a clinical setting, have a predictable dose, and would not have chemical impurities thus impacting the wound healing process. Lynntech's team is developing a simple, chemical synthesis methodology for generating sufficiently sustained and high purit ies of NO ex-situ for dermal applications, and thus allows for application of a topical gel' to wound treatments specifically diabetic foot ulcers. Preliminary results have shown the ability of this chemistry to efficiently produce sustained amounts of NO in a concentration dependant manner, and application of the NO gel to full thickness burns in a rodent model has also shown significant improvements in rate of healing (wound closure) and re-epithelization. In Phase I of this project, Lynntech's team wi ll pursue analytical, in vitro and in vivo studies in preparation of preclinical trials to be conducted in Phase II. Phase I will focus on characterization and optimization of the chemistry and gel matrix which will allow for a predictable dose on a given diabetic ulcer. Also, the project will characterize the antimicrobial effectiveness against clinically relevant pathogens and will conclude with in vivo evaluation of a high and low dose treatment of diabetic ulceration using two different dose timing prot ocols. The purpose of the Phase I and II projects is to complete preclinical trials to support filing of an IND with the FDA and concurrent marketing of the technology to the pharmaceutical sector. PUBLIC HEALTH RELEVANCE According to the American Diabetes Association, 6.3% of Americans have diabetes. One of the common complications associated with diabetes is lower extremity ulceration. In fact, diabetes is the most frequent cause of non-traumatic lower limb amputations. Diabetic foot ulceration (DFU) is a major problem that significantly impairs the quality of life of the patient, leads to prolonged hospitalization, and may require a major amputation. By reducing the time to heal DFU and protect against infection by using a single, inexpensive and safe top ical gel, patients can expect better healing outcomes, shortened hospital stays and medical care duration, and reduced cost for that care.