Development of a Novel Method for Inhibiting Atherosclerosis in Diabetes

DESCRIPTION (provided by applicant): The long term objective of the proposed studies is to develop a monoclonal antibody that can be administered safely to patients with diabetes to determine if it can inhibit atherosclerosis. Insulin-like growth factor-l (IGF-I) has been implicated in initiating the proliferative phase of atherosclerotic lesion development but inhibiting IGF-I receptor activity may lead to toxicity. IGF-I functions cooperatively with the aV?3 integrin to stimulate smooth muscle celll(SMC) division and migration which are related to the development of atherosclerosis. Therefore the purpose of these studies will be to determine if targeting the aV?3 integrin disrupts IGF-I stimulated atherosclerotic lesion progression. A specific monoclonal antibody directed against the cysteine loop (amino acids 177-183) of the 03 subunit of the aV|33 integrin will be prepared and tested to determine if it inhibits IGF-I stimulated SMC growth and migration in vitro and if this response is due disruption of IGF-I receptor linked signaling mechanisms that lead to stimulation of cell growth. To determine if this antibody has efficacy in vivo Fab fragments of the antibody will be prepared and will be infused into the arteries of pigs that are developing atherosclerotic lesions. A control antibody will be infused into one of the lesion areas to rule out the possibility of nonspecific effects due to autoimmunization. To obtain the structural information that will be necessary to prepare a humanized form of the antibody the clone of cells secreting the antibody will be isolated and the cDNAs corresponding to the heavy and light chains will be amplified using RTPCR. The cDNAs will be isolated, cloned and their sequences determined. The antibody structure will be used to design humanized form of the antibody in phase II. These studies should definitively test the hypothesis that inhibiting IGF-I actions by inhibiting ligand occupancy of aV?33 in blood vessel walls inhibits atherosclerotic lesion progression. If these results show that this approach is feasible a humanized version of this monoclonal would be prepared, purified and tested for toxicity. The long term objective would be to administer this antibody to diabetic patients with atherosclerosis who have wide spread diffuse disease that is not amenable to current therapies such as drug eluting stents. Since atherosclerosis is the cause of death in 80% of diabetics and there is no currently available therapy that specifically treats atherosclerosis in diabetics there is a major need for new therapies that are directed toward the treatment of this complication.