Grow your own

Imagine this: a car crash victim who suffers serious trauma to the brain avoids neurological damage after the doctors regenerate his lost brain matter using stem cells in the lab. In the future, this could become reality. A research team from Karolinska Institutet in Sweden has tried this in experimental trials on rats and mice with positive results.

At the scientific AAAS annual meeting in Boston yesterday, Paolo Macchiarini, a professor of regenerative surgery at Sweden's Karolinska Institute, revealed how pioneering stem cell-based transplant technology is being developed and tested on new organs and tissues. Macchiarini is renowned for a groundbreaking transplant in 2011 where a patient successfully received an artificial trachea (windpipe) covered in his own stem cells.

To date, five operations replacing diseased windpipes have been done using this technique. Next month, Macchiarini plans to operate on a two-year-old girl in the US who was born without a trachea and has lived her entire life in intensive care.

Macchiarini also plans to use the technique to recreate more complex tissues, such as the oesophagus and diaphragm, or organs such as the heart and lungs. "The aim is to make as much use of the body's own healing potential as we can," he says.

The term "stem cell" first appeared in scientific literature in 1868, when German biologist Ernst Haeckel used the phrase to describe the fertilised egg that becomes an organism, and also to describe the single-celled organism that acted as the ancestor cell to all living things in history. Scientists have been researching these cells for many years to unlock their secrets.

Most recently, the focus has been on induced pluripotent stem cells (iPSCs), which are generated by reprogramming a mature cell type into an immature state. These stem cells can then, in theory, be coaxed to become any type of specialised cell. They hold potential not only for drug development but also for studying disease.