The world of genetic engineering continues to advance with scientists now revealing that they have successfully grown the limb of a rat in a lab, containing functioning muscle tissue and veins.

Scientists hope that this will advance the use of genetic engineering in medicine and they hope to one day regrow missing limbs by using genetic material from the patient.

The new concept was published in the journal Biomaterials and revealed that researchers working at Massachusetts General Hospital successfully grew the limb of a rat. This new procedure is a complicated one, according to senior author of the paper at the MGH Department of Surgery and Center for Regenerative Medicine, Harrold Ott. Limbs contain muscles, bones, cartilage, tendons, blood vessels, nerves and ligaments that all must be rebuilt piece by piece, and require a supporting structure that researchers refer to as "the matrix."

Despite these difficulties, this latest news is truly groundbreaking and is most welcome by all those who must live with a non-functional limb. According to the latest data, approximately 1.5 million Americans have lost a limb. But thanks to new discoveries like this one, and the latest advancements in prosthetic limb technology that have improved both in appearance and functionality, sufferers are less exposed to helplessness.

Just under a month ago, the world was buzzing as a man was able to control a prosthetic limb with enough dexterity and sensitivity to make it part of his every day life. But this latest procedure takes the world artificial way entirely.

Currently there is an intermediate phase as physicians have successfully transplanted donor hands to individuals. However, these types of procedures come with lifelong risks from immunosuppressive therapy.

The hope of researchers is that by using a patient's progenitor cells to regenerate tissue, they will be able to create and develop a natural and like-scale limb from nothing rather than relying on a donor limb. This would reduce the chance of rejection by the body meaning that immunosuppressive therapy would not be necessary.

This new procedure is only the first phase, as researchers learn what is required to successfully regrow a useful limb for patients.

"We have shown that we can maintain the matrix of all of these tissues in their natural relationships to each other, that we can culture the entire construct over prolonged periods of time, and that we can repopulate the vascular system and musculature" Ott says.