Apolipoprotein A-I mimetic peptides.

Despite identical amino acid composition, differences in class A amphipathic helical peptides caused by differences in the order of amino acids on the hydrophobic face results in substantial differences in antiinflammatory properties. One of these peptides is an apolipoprotein A-I (apoA-I) mimetic, D-4F. When given orally to mice and monkeys, D-4F caused the formation of pre-beta high-density lipoprotein (HDL), improved HDL-mediated cholesterol efflux, reduced lipoprotein lipid hydroperoxides, increased paraoxonase activity, and converted HDL from pro-inflammatory to antiinflammatory. In apolipoprotein E (apoE)-null mice, D-4F increased reverse cholesterol transport from macrophages. Oral D-4F reduced atherosclerosis in apoE-null and low-density lipoprotein (LDL) receptor-null mice. In vitro when added to human plasma at nanomolar concentrations, D-4F caused the formation of pre-beta HDL, reduced lipoprotein lipid hydroperoxides, increased paraoxonase activity, and converted HDL from pro-inflammatory to antiinflammatory. Physical-chemical properties and the ability of various class A amphipathic helical peptides to activate lecithin cholesterol acyltransferase (LCAT) in vitro did not predict biologic activity in vivo. In contrast, the use of cultured human artery wall cells in evaluating these peptides was more predictive of their efficacy in vivo. We conclude that the antiinflammatory properties of different class A amphipathic helical peptides depends on subtle differences in the configuration of the hydrophobic face of the peptides, which determines the ability of the peptides to sequester inflammatory lipids. These differences appear to be too subtle to predict efficacy based on physical-chemical properties alone. However, understanding these physical-chemical properties provides an explanation for the mechanism of action of the active peptides.

Vertebral artery dissection following intravascular catheter placement: a case report and review of the literature.

Vertebral artery dissections (VAD) are known to occur as a result of mechanical manipulations of the cervical region, traumatic injury, iatrogenic injury and are also known to arise spontaneously. We report a case of vertebral artery dissection following vertebral artery cannulation during a central line placement and review the literature. The patient underwent intravascular catheter placement that subsequently demonstrated arterial blood. Duplex ultrasound and computed tomographic (CT) scan confirmed vertebral artery cannulation. The catheter was removed at the bedside with pressure, and a subsequent duplex ultrasound scan revealed a vertebral artery dissection. There were no neurological sequelae. The patient was successfully anticoagulated with warfarin but died from unrelated complications. This case report describes the rare iatrogenic event of VAD and reviews its etiology, diagnosis, complications, and management.