Your Body

Science World, Jan 17, 2000 by Sharon Guynup

IN THE NEXT CENTURY, WILL YOUR BODY GROW ITS OWN SPARE PARTS?

HEART

TODAY: Surgeons replace damaged heart valves (which control blood flow) with plastic or metal valves, or valves taken from pigs, lambs, or other animals.

TOMORROW: Scientists will sprout new heart valves from a patient's own cells.

ORGANS

TODAY: Researchers can grow small of pieces of human liver tissue but haven't developed the the technology to use this tissue for transplants.

TOMORROW: Within 10 to 20 years, will routinely receive transplanted hearts livers, and kidneys--all grown from human tissue in the lab.

NERVES

TODAY: Doctors reconstruct nerves damaged by disease or injury using pig nerve cells cultivated in laboratories. The process of replacing human tissues with animal tissues is called xenotransplantation (ZEE-no-trans-plan-TA-shun).

TOMORROW: Artificial nerves will be made from synthetic material called polymers.

LIMBS

TODAY: Doctors replace legs and arms with prosthetic, or artificial, limbs. They attach fake limbs to the peripheral (puh-RIF-er-ul) nervous system, which connects the brain and spinal cord to muscles that help move the new limb.

TOMORROW: Doctors will use prosthetic limbs that actually feel sensation by connecting wires to the central nervous system (the brain and spinal cord).

BONE AND CARTILAGE

TODAY: Doctors inject hormones, chemicals that affect body functions, into fractured jaws and other bones to help them regenerate or regrow.

TOMORROW: The body will produce its own new bone and cartilage (connective tissue between bones). Surgically implanted plastic "scaffolds" will act as molds for bone and cartilage cells to grow on. As cells multiply, scaffolds will slowly dissolve.

HAIR

TODAY: People who lose their hair can opt for surgical hair or scalp transplants, but these are often unsuccessful--or unattractive.

TOMORROW: Doctors will stimulate hair to regenerate using special growth proteins (substances used in many body functions, including hair growth).

EYES

TODAY: Doctors correct near- or farsightedness (vision defects) with laser surgery (using intense light beams instead of a scalpel).

TOMORROW: Doctors will surgically implant permanent lenses to correct vision, removing the need for contact lenses or glasses.

SKIN

TODAY: Researchers manufacture replacement skin in 7.5 centimeter (3-inch) sheets, made from human cells and synthetic or manmade, substances. The new skin heals severe burns and other injuries.

TOMORROW: The body grows new skin from stem cells (immature cells that haven't yet turned into blood, nerve, or other specialized cells). Stem cell growth will be stimulated by growth hormones (chemicals that trigger body parts to grow).

BLOOD VESSELS

TODAY: Researchers make use of pig cells and polymers (synthetic materials) to build new veins and arteries. But the human immune system often rejects the foreign cells. So patients must take anti-rejection drugs, which may have serious side effects.

TOMORROW: New veins and arteries will grow directly from a patient's own cells to avoid immune-system rejection.

DO YOU KNOW?

The first animal-to-human organ transplants were performed:

* in the Middle Ages

* in the early 20th century

* in 1995

This Issue's Answers

p. 13: in the early 20th century