Abstract
Peripheral arterial disease is a serious manifestation of atherosclerosis in the lower
extremities. Current interventions approved by FDA are either ineffective or have a
modest effect. Surgical revascularization is the only viable option for PAD subjects;
however, the stents can fail. Patients with PAD have marked defects in skeletal muscle
metabolism, where the aerobic and anaerobic metabolism are uncoupled, increased
acidification of the skeletal muscle and decreased ATP synthesis. In glycolytically active
tissue, such as skeletal muscle, there are present histidyl dipeptides, such as carnosine
which buffers intracellular pH, under ischemic conditions and facilitate the utilization of
glucose during exercise and ischemia. Recent evidence from our laboratory shows that
in addition to buffering, carnosine chelates first transition metals and improves
angiogenesis, forms conjugates with reactive aldehydes derived from lipid peroxidation
and regress atherosclerosis. Hence enhancing carnosine via supplementation, which
easily permeates through the ischemic muscle, is easily could be a feasible therapeutic
that can target the underlying pathophysiological associated with PAD and increase limb
function. To achieve this goal, we will treat the PAD subjects with carnosine and examine
whether the carnosine supplementation improves the lower extremity function. Second,
we will perform extensive mechanistic studies to elucidate the mechanism by which
carnosine improves the muscle function and finally we will follow these subjects and
determine if carnosine has durable effects. Collectively, our pilot clinical trial will help us
test the efficacy of carnosine as a low-cost therapeutic intervention for PAD patients and
the data generated will serve as a strong rationale to design large definitive Phase III
clinical trial for carnosine.