Cerebral Changes In Physiologic Aging

Aging is an inescapable natural biologic process affecting all organ systems of the body. This process, regulated by genetic factors (longevity genes) and influenced by environmental factors, begins after age 50 to 60 years or later. Aging of the central nervous system primarily

Hydrocephalus Vacuo

FIGURE 2.21

A. Normal pressure hydrocephalus in a 60-year-old man with "gait difficulties over the years" and memory decline. MRI shows enormously enlarged ventricles and only mildly enlarged subarachnoid space. B. Hydrocephalus ex vacuo in a 70-year-old demented patient. CT scan shows enlarged ventricles and significantly widened subarachnoid space.

Lipofuscin Accumulation Brain

FIGURE 2.22

Cerebral changes in physiologic aging. A. MRI showing periventricular caps around the anterior horns. B. Lipofuscin accumulation in thalamic neuron in the brain of a 73-year-old man (HE). C. Neuritic plaque in hippocampus (Bodian stain). D. Abundance of corpora amylacea in the pia matter (immunostain for ubiquitin). E. Siderocalcinosis of small blood vessel in basal ganglia (HE).

Siderocalcinosis

FIGURE 2.22

Cerebral changes in physiologic aging. A. MRI showing periventricular caps around the anterior horns. B. Lipofuscin accumulation in thalamic neuron in the brain of a 73-year-old man (HE). C. Neuritic plaque in hippocampus (Bodian stain). D. Abundance of corpora amylacea in the pia matter (immunostain for ubiquitin). E. Siderocalcinosis of small blood vessel in basal ganglia (HE).

manifests with cerebral atrophy—a reduction of brain volume. The morphologic changes are clinically undiscovered for some time. The appearance of neurologic decline, chiefly motor dysfunction, and of cognitive decline, chiefly memory impairment, varies greatly among individuals.

CT scan and MRI demonstrate the atrophy as a widening of the subarachnoid space and cisterns, reduction of hemispheric white matter, and enlargement of lateral ventricles. Frequent, incidental age-related findings are periventricular caps and rims corresponding to periventricular ischemic demyelination (Fig. 2.22).

FIGURE 2.23

Cerebral artifacts. "Swiss cheese" brain showing A. multiple smooth-walled cavities, B. corresponding to empty holes lacking tissue reaction (HE). Artificial histologic changes. C. Dissolution of granule cells in cerebellar cortex. D. Spiky neurons in surgical specimen (HE).

The pathomechanism of cerebral aging is complex. Mitochondria play a central role in the aging process. With advancing age, the amount of mitochondria-derived free oxygen radicals increases, damaging cellular lipids and proteins and the mitochondrial DNA. This oxidative stress is not effectively countered due to a decline in antioxidant defense mechanisms. It is noteworthy that aging increases the risk for neurodegenera-tive diseases, vascular diseases, and malignancies, all leading causes of death in the elderly.

How to Stay Young

How to Stay Young

For centuries, ever since the legendary Ponce de Leon went searching for the elusive Fountain of Youth, people have been looking for ways to slow down the aging process. Medical science has made great strides in keeping people alive longer by preventing and curing disease, and helping people to live healthier lives. Average life expectancy keeps increasing, and most of us can look forward to the chance to live much longer lives than our ancestors.

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