The Natural Healing Process

The human body has an amazing ability to heal itself. However, some injuries, such as severe burns, heart attacks, and spinal cord injuries, are too severe for the body to heal on its own.

Regenerative medicine is showing great promise in healing these kinds of injuries!

Natural Healing

Steve was out riding his dirt bike when he wiped out and broke his arm. The doctors set his arm in a cast. While he waited for that itchy cast to come off, just exactly what was going on inside it?

In the first few days, the blood clotted to keep the wound from bleeding. Then immune cells like  “macrophages” got rid of any bacteria or excess cells that would interfere with the healing process.

Everybody has a store of extra cells in the bone marrow and skin, called stem cells. Some of Steve’s stem cells migrated to his wound. There they created new skin cells and blood vessels to replace the damaged cells and tissue.

The immune system and stem cells

Any injury automatically sets off an inflammatory reaction. The body’s immune system sends signals that help stem cells find the site of injury.

The call of “injury!” also releases clumps of growth factors that we all have circulating in our bodies, just waiting for these signals. They usually travel the body surrounded by platelets– the cells that clot the blood to stop bleeding. When they are summoned, both are released to do their job!

The platelets clot the blood. The growth factors tell the stem cells that have arrived at the site to MULTIPLY AND DIFFERENTIATE.

Over the next few weeks, cells in Steve’s body, called fibroblasts, laid down an extracellular matrix of collagen, which networked the tissue together. New blood vessels were also produced, and they brought vital oxygen and nutrients to the healing tissue. Next, the edges of the wound pulled together and the skin started to grow back.

Finally, after several months, scar tissue was formed. Scar tissue is also made of collagen, and it makes the site of the injury tougher. However, it’s not quite as strong as the original tissue. At that point, voila! Steve’s cast came off, and his arm was just about as good as new.

Formation of a scar

When the injury overwhelms the body’s ability to heal, it instead creates scar tissue. Scar tissue is similar to the healthy tissue, except it’s disorganized and structurally weaker.

Scar tissue on your skin will not tan as easily and will be less flexible. Scar tissue on the heart will also be less flexible, which increases the likelihood of further damage to the heart.

The one exception is in the bone. Sometimes, bones will actually be stronger after a break!

Healing happens in all the tissues of the body, following the same general steps:

- Inflammatory reaction, which includes clotting
- Cell proliferation
- Regrowth, using the body’s natural scaffold as support
- Scarring

As we’ve seen, Steve’s body did a great job of healing his broken arm. But sometimes, an injury or disease may be beyond the capacity of the body’s natural healing ability. The injury may have hurt so many cells—so much tissue—that the body simply cannot make enough new cells to fill the damaged area. When the damaged area is too large, new capillaries have trouble growing into it. Without capillaries to deliver nutrients and oxygen in the injury site, no new cells can nestle and grow.

Also, sometimes the nature of the injury can make for a very harsh environment for new cells. For example, in the case of a spinal cord injury, harsh chemicals are released that threaten the survival and development of new cells.

These are situations where regenerative medicine can help!