Abstract 11083: A Novel Approach to Oral ApoA-I Mimetic Therapy

Abstract

Recent studies indicate that regardless of whether the peptide is administered orally or by injection, the intestine is a major site for the action of apoA-I mimetic peptides such as 4F. These studies together with recent clinical trials suggest that doses of 40 to 100 mg/kg/day will likely be required for efficacy. The cost of providing chemically synthesized peptides at these doses makes it unlikely that this form of therapy would be practical for treating chronic diseases. The peptide 4F requires blocking groups (which can only be added by chemical synthesis) for its efficacy. In contrast the peptide 6F (DWLKAFYDKFFEKFKEFF) when chemically synthesized from all L-amino acids without blocking groups and administered to apoE null mice in a Western Diet (WD) at a dose of 60 mg/kg/day (~0.03% of the diet by weight) significantly decreased serum amyloid A (SAA) levels (p = 0.001) and decreased the percent of aorta with atherosclerosis (p = 0.0006). Encouraged by these results, we generated transgenic tomato plants carrying either an empty vector (pBI121) or one that expressed the 6F peptide. The vectors contained a kanamycin resistance gene that allowed for selection of transgenic plants. Transgenic plants were selected for homozygosity and the homozygous seeds were grown into plants. The homozygous ripened 6F tomatoes and their controls were harvested and lyophilized. The lyophilized tomatoes were ground and added to WD to give LDLR null mice a daily dose of 40 mg/kg/day of L-6F, which was contained in tomato powder constituting 2.2% of WD by weight. Feeding the tomatoes containing 6F for two weeks significantly reduced plasma SAA levels (p = 0.0093) and increased plasma paraoxonase activity (p<0.0001) compared to control tomatoes. Feeding the 6F tomatoes also decreased plasma levels of 13-HODE (p = 0.0406), 5-HETE (p = 0.0360), 15-HETE (p = 0.0098), PGD2 (p = 0.0096), lysophosphatidic acid (LPA) 16:0 (p = 0.432), and LPA 20:4 (p = 0.0013) compared to control tomatoes. We conclude that a novel practical approach to oral apoA-I mimetic therapy is to express the peptide in edible plants, which can be fed.