Red Ragged Fibers

Diseases of the mitochondria can be caused by defects in nuclear or mitochondrial DNA and result in decreased energy availability for cell processes. When muscle is stained with Gomori Trichrome, characteristic ragged-red fibers are visible under the microscope. This appearance is due to the accumulation of abnormal mitochondria below the plasma membrane of the muscle fiber. These may extend throughout the muscle fiber as the disease severity increases. The mitochondrial aggregates cause the contour of the muscle fiber to become irregular, causing the "ragged" appearance. Besides muscle, what other tissues would you expect to suffer the most damage from a mitochondrial defect?