ArteFill® Permanent Injectable for Soft Tissue Augmentation: II. Indications and Applications

Patients ask for procedures with long-lasting effects. ArteFill is the first permanent injectable approved in 2006 by the FDA for nasolabial folds. It consists of cleaned microspheres of polymethylmethacrylate (PMMA) suspended in bovine collagen. Over the development period of 20 years most of its side effects have been eliminated to achieve the same safety standard as today’s hyaluronic acid products. A 5-year follow-up study in U.S. clinical trial patients has shown the same wrinkle improvement as seen at 6 months. Long-term follow-up in European Artecoll patients has shown successful wrinkle correction lasting up to 15 years. A wide variety of off-label indications and applications have been developed that help the physician meet the individual needs of his/her patients. Serious complications after ArteFill injections, such as granuloma formation, have not been reported due to the reduction of PMMA microspheres smaller than 20 μm to less than 1% “by the number.” Minor technique-related side effects, however, may occur during the initial learning curve. Patient and physician satisfaction with ArteFill has been shown to be greater than 90%

Colocalization of Protein Kinase A with Adenylyl Cyclase Enhances Protein Kinase A Activity during Induction of Long-Lasting Long-Term-Potentiation

The ability of neurons to differentially respond to specific temporal and spatial input patterns underlies information storage in neural circuits. One means of achieving spatial specificity is to restrict signaling molecules to particular subcellular compartments using anchoring molecules such as A-Kinase Anchoring Proteins (AKAPs). Disruption of protein kinase A (PKA) anchoring to AKAPs impairs a PKA-dependent form of long term potentiation (LTP) in the hippocampus. To investigate the role of localized PKA signaling in LTP, we developed a stochastic reaction-diffusion model of the signaling pathways leading to PKA activation in CA1 pyramidal neurons. Simulations investigated whether the role of anchoring is to locate kinases near molecules that activate them, or near their target molecules. The results show that anchoring PKA with adenylyl cyclase (which produces cAMP that activates PKA) produces significantly greater PKA activity, and phosphorylation of both inhibitor-1 and AMPA receptor GluR1 subunit on S845, than when PKA is anchored apart from adenylyl cyclase. The spatial microdomain of cAMP was smaller than that of PKA suggesting that anchoring PKA near its source of cAMP is critical because inactivation by phosphodiesterase limits diffusion of cAMP. The prediction that the role of anchoring is to colocalize PKA near adenylyl cyclase was confirmed by experimentally rescuing the deficit in LTP produced by disruption of PKA anchoring using phosphodiesterase inhibitors. Additional experiments confirm the model prediction that disruption of anchoring impairs S845 phosphorylation produced by forskolin-induced synaptic potentiation. Collectively, these results show that locating PKA near adenylyl cyclase is a critical function of anchoring