Turning skin into eyes – stem cells hint at future medical treatments

The big green blobs are retinal cells. Image: courtesy David Gamm, UW-Madison.

American scientists have taken a step towards a treatment for macular degeneration and other conditions which can cause loss of vision. For the first time, the scientists have shown that stem cells created from cells taken from the skin can be turned into cells from the retina – the light-sensing part of the eye.

The breakthrough raises the possibility that one day doctors will be able to carry out retinal transplants using pieces of retina grown from a patient’s own skin cells, which reduces the chance that any treatment might be rejected by the patient’s immune system. It also avoids the ethical concerns raised by the only available alternative, which involves using retina grown from embryonic stem cells.

Transplanting pieces of retina grown from stem cells is seen as a potential cure for conditions such as macular degeneration. People suffering from macular degeneration gradually lose the light-sensitive cells in their eyes. It is the most common cause of blindness and most often affects older people. In 2008, scientists and doctors demonstrated that transplanting patches of retinal cells into the eye of patients with macular degeneration could partly restore their vision. Unfortunately, such a treatment is still a long way away from becoming a standard medical procedure.

To grow the new retinal cells the scientists took skin cells and persuaded them to become stem cells by adding specific genes. These genes control the activity of other genes, and adding them to skin cells can “induce” the cells to become stem cells. The stem cells – known as “induced pluripotent stem cells”, or iPS – were then persuaded to turn into retinal cells of various kinds; something that has never been done before.

As the retinal cells develop in the laboratory in the same way as they do in a human embryo, the breakthrough will also make it much easier in future for scientists to investigate how our eyes and nervous systems develop.

All the fun of the festival – part 2

Streamers fly above Cheltenham Town Hall

As I mentioned, I managed to attend quite a few talks at Cheltenham on Thursday. I’ve summarised the first three below.

Rutherford

The first talk was quite interesting. We heard about Ernest Rutherford’s life and family in a presentation given by his great granddaughter, followed by an explanation of the science he did that earned him his reputation and a Nobel Prize for chemistry. The explanation of the modern work on nuclear physics left me slightly confused, but the central message – that the inside of an atomic nucleus can be a very complicated place – was something I hadn’t truly grasped before.

The future for stem cells

An excellent talk, chaired by Robert Winston, and followed by some very moving and thought-provoking questions. The speakers described stem cell therapies for various things: growing replacement cartilage (and a whole new windpipe for one patient!), replacing damaged retinal cells to treat macular degeneration, and various other things. The audience’s questions ranged from the political –should funding be concentrated on embryonic or adult stem cell research – through to very personal questions about treatments.

In particular, two questions made me sit up and realise how important and personal a topic stem cell therapy is, and how careful the media must be not to give people false hope. One elderly gentleman began his question with the phrase “I seem to have found myself in possession of an eighty year-old brain”, and went on to ask about using stem cells to support and regenerate the central nervous system. The second was an 86 year-old lady who asked whether treatment for macular degeneration would be available in her lifetime. When the speaker replied that it would likely be a few years until it was routine, she offered herself as a “guinea pig”.

Can science make you happy?

This was presented solely by Robert Winston, who rattled through various things that affect our mood and emotions. Less focussed than the other talks of the day, it was nevertheless a great pleasure to listen to him work his way through some interesting science and anecdotes on subjects as diverse as the terrible accident that befell one Phineas Gage, and paintings by the artist Il Bronzino.

We were fortunate enough to meet Sir Winston at a book signing afterwards, and he came across as a very warm, friendly and humble man.

Look out for more on the evening’s talks in a future post.

Fighting the fallout – genetics and radiation damage

Ionising radiation is nasty stuff. You can’t see it, hear it or smell it, yet it can cause terrible damage to the DNA in our cells. The Earth is covered with naturally occurring sources of radiation so, as you might expect, we have evolved ways to repair the damage it causes. How our cells controlled these repairs was only poorly understood, until now.

We’ve known for a while that different people are sensitive to different levels of radiation. Now, according to a paper published in the journal Nature this week, American researchers have found the genes that control our cell’s response to the damage caused by radiation. They’ve also singled out several genes that no-one knew were involved with fixing radiation damage in our cells.

Learning something about how our bodies work is great, and as we know so little about the function of many human genes this work is quite exciting, but does it actually have any practical uses?

Absolutely! Many modern medical treatments rely on radiation, either to allow doctors to “see” inside the body, or to destroy specific cells and tissues. By knowing how a patient will react to exposure to radiation, we could improve the effectiveness of treatments like radiotherapy, or reduce the risk of unwanted side effects from radioactive imaging techniques.

A final thought: in the future, humanity might venture away from the Earth’s protective magnetic field. There is one important barrier to doing so, however: astronauts will be exposed to radiation in the form of harmful high energy particles from the sun or from deep space. By knowing how our cells control our response to radiation damage, could we develop ways to protect our astronauts from such risks?