Free Radicals in Ophthalmic Disorders PDF

Preface

Over the last few decades, free radical biology has evolved into a discipline addressing various pathologic processes at the molecular level. In the past, the reactive oxygen–derived radicals and nitric oxide have been extensively studied in ischemia-reperfusion, involving cardiac, neuronal, hepatic, pulmonary, gastrointestinal, and other organs. Recently, in the eye, the role of free radicals in pathogenesis of cataract has gained momentum in delineating the effect of oxidative stress and antioxidant depletion in cataract formation. In the lens, extensive studies were conducted in evaluating both offending radicals and protecting agents against such insult. Most noteworthy, in recent years, the free radical biology has extended significantly in addressing other ophthalmic disorders, including macular degeneration, retinal degeneration in glaucoma, diabetic retinal complications, and intraocular inflammation or uveitis. For the first time, the pathogenesis of these diseases is seen from the context of free radical generation. The workshop held in Ettal in 2005 provided a unique opportunity for a gathering of free radical biologists with interest in basic biochemical interactions and ophthalmic scientists devoted to the field of oxidative stress and ophthalmic diseases. At that event, we came up with the idea to summarize the current status of free radical biology in addressing various ophthalmic diseases in form of a book.

Recent studies on free radical–related ophthalmic diseases are distributed in diverse ophthalmic and nonophthalmic journals, and no effort has been made to summarize our knowledge in a single periodical or a book. The current book, Free Radicals in Ophthalmic Disorders, summarizes recent advances in free radical insults leading to various ophthalmic diseases. The conditions that are addressed include cataract, macular degeneration, diabetic retinopathy, corneal diseases, retinal degeneration, glaucoma, retinal ischemia, and intraocular inflammation or uveitis. Each chapter addressing these diseases is orderly, presented with a brief introduction of the disease and followed by the role of free radicals in the pathogenesis of the disorder and the potential therapeutic intervention with antioxidants and/or other means.

In cataract, the current understanding of the mechanism of cataract formation and the protection by specific antioxidants were discussed. The feasibility of treating the diabetic retinopathy with peroxynitrite-scavenging agents was introduced. In corneal disease progression, the evidence of involvement of oxidants was shown, and in macular degeneration, the role of oxidative stress was reinforced. Linking to oxidation, antioxidants were also discussed in cardiovascular diseases. In glaucoma, retinal ganglion cell and trabecular meshwork cell death was ascribed to oxidative stress. The reduction of oxidative stress by tyrosinase is proposed in retinal diseases, and that the free radical formation is an element in retinal ischemia was demonstrated. In uveitis, the early involvement of mitochondrial peroxynitrite was demonstrated. Aside from the direct link of oxidants to eye diseases, the general aspects of oxidative and nitrative stresses were also discussed. Therefore, this book, which spans every aspect of ocular diseases, might bring a unifying understanding of the involvement of free radicals in disease as well as in health.

The editors of the volume are appreciative of the contribution of various authors, who succinctly presented the current material with background pertinent to their topics and who focused on biological changes in the ocular tissues resulting from free radicals.