Aging is a process we all face, though some see signs faster than others. And while most people focus on their appearance, changes at the cellular level are critical to our health and are of particular interest to scientists tackling the question of why we age. One way researchers are learning about the process is by studying a condition called progeria, a rare genetic condition that causes rapid aging in children.
How do cells age?
Cells in our body have different responsibilities. Some are constantly reproducing, such as those in the gastrointestinal tract; others are capable of reproducing, if damaged, such as those inside the arteries, and still others cannot reproduce at all, such as nerves, the heart and muscles.
The four basic types of tissue in our body include: connective tissue, which supports other tissues and binds them together (bone, blood, lymph tissues); epithelial tissue, a lining for passages inside the body (gastrointestinal system); muscle tissue, which moves the skeleton (also smooth muscle and cardiac muscle); and nerve tissue, which is made up of neurons carrying messages to different parts of the body (brain and spinal cord).
As these types of tissue age, different changes take place. All aging cells become larger and less able to divide and multiply. There also is an increase in cell lipids and pigments, and a buildup of waste products begins to occur. Cells start to lose their ability to function, or they don’t function properly. Connective tissue will become stiff, which makes the organs, blood vessels and airways also less flexible. Cell membranes will have trouble getting oxygen and nutrients, and tissues will begin to lose mass.
Because of these cell changes, organs will also begin to change with age. They slowly lose function, but generally we don’t notice. The biggest changes occur in the heart, lungs and kidneys, but how much they change depends on the individual. This makes it harder for the body to restore balance, and overtaxed organs may cause problems, such as heart failure. Because the aging process is complicated, it’s hard to know which changes are a result of aging and which are due to medical problems.
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Why do we age?
There are several theories as to why we age, though none is definitive. One theory suggests we age from injuries over time from ultraviolet light, normal wear and tear on the body and by-products of metabolism. Another suggests overuse of your organs through a poor diet and excessive consumption of alcohol, drugs or cigarettes can cause irreparable damage to the body. Yet another theory suggests that aging is predetermined by your DNA, and the process is controlled by your genes. But most gerontologists believe that aging is due to the interaction of several influences, including heredity, environment, culture, diet, exercise, and past illnesses. The interesting thing about aging is that it occurs at different rates in the body and among people. There is just no way to predict how an individual will age.
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What is progeria?
Progeria, or Hutchinson-Gilford progeria syndrome, is a rare genetic disorder that causes rapid aging in children. Children with the syndrome typically look normal at birth, but do not grow properly and develop characteristic facial features, such as thin nose with a beaked tip, prominent eyes, thin lips, a small chin and large ears. The aging process causes hair loss, older-looking skin, joint problems and a loss of fat, but does not affect intellectual development or motor skills. People with this syndrome experience a severe hardening of the arteries and will often die of heart attack or stroke in their teens.
What happens to the cells of people with progeria?
The condition occurs in only one in 4 million newborns worldwide. It occurs because of a mutation in the LMNA gene. This mutation disrupts the function of a critical protein that makes up cells, creating an abnormal version of the protein instead. This altered protein results in cells aging and dying prematurely.
Are there any treatments for this disorder?
A new study published in Proceedings of the Natural Academy of Sciences has found that a drug first used to treat cancer showed significant improvements in bone structure, weight gain and the cardiovascular system of children suffering from progeria. The drug, a farnesyltransferase inhibitor (FTI), was used in the first clinical drug trial for the condition.
The study involved 28 children from 16 different countries, which accounts for 75 percent of all progeria cases. The children were given the drug twice a day for two and a half years. Researchers inspected the weight, stiffness of arteries and bone rigidity and density of the children over the course of the study, and found that all of them improved in at least one of the measurements. They saw a 50 percent increase in annual weight gain, bone rigidity improved to normal levels, and arterial stiffness decreased by 35 percent, and vessel wall density improved.
Though this is not a cure for the disease, a second clinical trial is underway, and may lead not only to new information about progeria, but also about the normal aging process and cardiovascular disease.
Saltsman, Kirstie. (2011, April 22). “Chapter 5: The Last Chapter: Cell Aging and Death.” National Institute of General Medical Sciences. Retrieved from http://publications.nigms.nih.gov/insidethecell/chapter5.html
Dugdale, III, M.D., David. (2011, May 22). “ Aging changes in organs – tissue-cells.” MedlinePlus. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/004012.htm
Ward, Liz. “What causes aging?” Discovery Fit & Health. Retrieved from http://health.howstuffworks.com/wellness/aging/aging-process/aging-causes2.htm
n.p. (2007, July). “Huthinson-Gilford progeria syndrome.” Genetics Home Reference. Retrieved from http://ghr.nlm.nih.gov/condition/hutchinson-gilford-progeria-syndrome
n.p. (2012, September 25). "Drug Originally Developed For Cancer Proves Effective For Children With Progeria." Medical News Today. Retrieved from http://www.medicalnewstoday.com/releases/250674.php
Published On: October 02, 2012