ArgiNOx is a recently-formed Wisconsin-based biotech startup that seeks to develop novel therapies for cardiovascular and inflammatory conditions resulting from insufficient or excess nitric oxide (NO). In the cardiovascular system, NO is an endogenous vasodilator that must be produced at an appropriate level and tempo for sustained health. Type II diabetes is associated with an insufficiency of NO, resulting in excessive vasoconstriction and impaired blood perfusion of tissues. This dysfunction, termed """"""""diabetic vasculopathy,"""""""" is responsible for tissue ischemia, blindness, infections, amputations of digits and limbs and ultimately, loss of life. Reversal and prevention of diabetic vasculopathy may be achieved by improving levels of NO bioactivity.
The Aim of proposed studies is to test the feasibility of a novel approach for potentially enhancing levels of vascular NO in a rodent model of type II diabetes. The new approach is based on knowledge that NOSs (members of the NO-producing family of enzymes) convert NG-hydroxy-L-arginine (NOHA) to NO and citrulline at a 2.5-fold faster rate than observed with the natural substrate, Arg. More important, we have discovered that NOHA is non-enzymatically converted to NO and citrulline by reaction with superoxide anion, the free-radical species that normally limits the bioactive lifetime of NO and which is overproduced by diabetic blood vessels. Thus, we hypothesize that diabetic vessels will paradoxically be more efficient than normal vessels at producing NO bioactivity when NOHA is administered as substrate, while they are less efficient with Arg as substrate. Proposed studies will test this fundamental concept by quantifying the relative efficacy of continuous NOHA vs. Arg administration at preventing and reversing measures of vascular dysfunction in the Zucker Diabetic Fat (ZDF) model of type II diabetes. Since OH-Arg is a natural product it is likely to be safe. Clear and measurable milestones are proposed that define success and will warrant progression to Phase II studies (measures of improved efficacy of NOHA, compared to ARG). US and foreign patent provide ArgiNOx with commercialization rights in this area. Successful demonstration of NOHA efficacy in this animal model will be followed Phase II pharmacokinetic/pharmacodynamic testing and FDA required preclinical studies. These studies may pave the way to development of a breakthrough therapy for vascular complications of diabetes in humans.
