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Neurodegeneration in Diabetic Retinopathy

Alistair J. Barber, William F. Robinson, and Gregory R. Jackson

CONTENTS

INTRODUCTION

HISTOLOGICAL EVIDENCE

BIOCHEMICAL EVIDENCE OF NEURODEGENERATION AND CELL DEATH

FUNCTIONAL EVIDENCE OF NEURODEGENERATIVE CHANGES

POTENTIAL MECHANISMS OF RETINAL NEURODEGENERATION IN DIABETES

SUMMARY AND CONCLUSIONS

REFERENCES

Keywords Neurodegeneration • Retinal ganglion cell • Nerve fiber layer • Caspases • Scotopic threshold response

INTRODUCTION

Neurodegeneration can be defined as a chronic, progressive loss of neuronal function and structural integrity, which usually includes the death and removal of neurons at an accelerated rate. In neurodegenerative diseases, the loss of neurons occurs gradually over a protracted period of time, such as the kind of neural loss that occurs in Parkinson’s or Alzheimer’s disease. The term neurodegeneration is used frequently in discussions of many disease pathologies that primarily affect neurons; however, neurodegenerative diseases have been more accurately defined as, “…neurological disorders with heterogeneous clinical and pathological expressions affecting specific subsets of neurons in specific functional anatomic systems; they arise for unknown reasons and progress in a relentless fashion” [1]. By this strict definition, neuronal loss in Alzheimer’s disease is classed as neurodegeneration; while acute loss of neurons in a stroke is not, although neurodegeneration is often modeled using experimentally induce ischemia to accelerate neuronal cell death.

Neurodegenerative diseases are commonly thought of as affecting the brain or peripheral nervous system, but this chapter will consider diabetic retinopathy as a candidate neurodegenerative disease of the retina. There are a series of features that are gener-

From: Ophthalmology Research: Visual Dysfunction in Diabetes

Edited by: J. Tombran-Tink et al. (eds.), DOI 10.1007/978-1-60761-150-9_12 © Springer Science+Business Media, LLC 2012

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