Читать книгу Aging - Harry R. Moody - Страница 75

Connective tissue in the body, such as the skin or the lens of the eye, loses elasticity with advancing age. We recognize the result as wrinkling of skin and cataracts. The explanation for this change lies in a substance known as collagen, a natural protein found in skin, bones, and tendons. According to the cross-linkage theory of aging, the changes we see result from the accumulation of cross-linking compounds in the collagen, which gradually become stiff. As in the waste accumulation theory, the piling up of harmful molecules is thought to eventually impair cell function. Some of this cross-linking may be caused by free radicals, which are cited in several theories of aging. Cross-linkage and collagen, therefore, are related to other changes in macromolecules and organ systems as they age (Bilder, 2016).