Activation of caspases is directly responsible for cell death. Morphologically, cells dying of programmed cell death appear atrophic and exhibit condensed nuclei. DNA extracted from cells dying of programmed cell death is often fragmented, and shows a characteristic ladder-type pattern on agarose gels upon electrophoresis.
Neurons also undergo programmed cell death.
It is believed that neuronal programmed cell death is a natural process during development. However, inappropriate activation of neuronal programmed cell death in adults may lead to neurodegenerative diseases, such as Alzheimer's disease. Recently, Dr. Chang has been investigating the neurotoxicity of cholesterol oxides. High levels of serum cholesterol and low density lipoprotein have been associated with the genesis of atherosclerosis, a leading cause of cardiovascular diseases that affect a large number of people in the United States and all over the world. There is strong evidence that cholesterol oxides cause cell death by an induction of programmed cell death.