New functional biomaterials for medicine and healthcare, 1st edition [Woodhead Publishing Series in Biomaterials, 67]

The book begins with an overview of the use of biomaterials in contemporary healthcare and the process of developing novel biomaterials; the key issues and challenges associated with the design of complex implantable systems are also highlighted. The book then reviews the main materials used in functional biomaterials, particularly their properties and applications. Individual chapters focus on both natural and synthetic polymers, metallic biomaterials, and bio-inert and bioactive ceramics

Hypoxia-inducible factor signaling mechanisms in the central nervous system

In the CNS neurons are highly sensitive to the availability of oxygen. In conditions where oxygen availability is decreased neuronal function can be altered, leading to injury and cell death. Hypoxia has been implicated in a number of central nervous system pathologies including stroke, head trauma, and neurodegenerative diseases. Depending on the duration and severity of the oxygen deprivation, cellular oxygen-sensor responses activate a variety of short- and long-term energy saving and cellular protection mechanisms.  Failure of synaptic transmission can be observed within minutes following this hypoxia. The acute affects of hypoxia on synaptic transmission are primarily mediated by altering ion fluxes across membranes, presynaptic effects of adenosine and other actions at glutamatergic receptors. A more long-term feature of the response of neurons to hypoxia is the activation of transcription factors such as hypoxia inducible factor. The activation of hypoxia inducible factor is governed by a family of dioxygenases called hypoxia inducible factor prolyl 4 hydroxylases (PHDs). Under hypoxic conditions, PHD activity is inhibited, thereby allowing hypoxia inducible factor to accumulate and translocate to the nucleus, where it binds to the hypoxia-responsive element sequences of target gene promoters. Inhibition of PHD activity stabilizes hypoxia inducible factor and other proteins thus acting as a neuroprotective agent. This review will focus on the response of neuronal cells to hypoxia inducible factor and its targets, including the prolyl hydroxylases. We also present evidence for acute effects of PHD inhibition on synaptic transmission and plasticity in the hippocampus.AM