Could stem cells cure BLINDNESS? Retina grown in a laboratory used to treat monkeys with rare genetic condition

A rare genetic condition which can cause blindness in families could be treated using stem cells following tests by scientists.

Researchers in Japan grew tissue grafts from human embryonic stem cells, which they used to treat monkeys suffering from retinitis pigmentosa (RP).

The inherited condition causes the light-sensitive cells in the retina – the tissue at the back of the eye – to gradually die, leading to sight loss.

A team of Japanese researchers have successfully used embryonic stem cells to treat animals with retinitis pigmentosa (RP), a rare inherited condition in which the light-sensitive cells in the retina gradually die. By growing tissue grafts from embryonic stem cells they were able to treat animals

But the new study has raised hopes that stem cells can be used as a treatment for the condition.

The research was carried out by scientists at the RIKEN Center for Developmental Biology in Kobe, Japan, who used human embryonic stem cells (ESCs) to grow new retinal tissue.

According to the RIKEN team, who published the study in the journal PNAS, the findings could pave the way for ESC-based retinal transplants in humans.

ESCs are effectively cellular blank slates which can develop into almost any type of cell in the body, given the right signals at the right time.

In order to grow new tissue for transplant, the team used human ESCs in the lab and coaxed them into becoming retinal cells for transplant.

When this new retinal tissue was transplanted to the eyes of animals with the condition, it helped them to regain their sight.

The approach has already moved to human trials to treat another sight-threatening condition, age-related macular degeneration (AMD).

But there are now hopes it could also help those suffering from RP.

Although RP is rare, it leads to failing vision in dim light and, if left untreated, it can lead to blindness.

In the first half of the experiment, the researchers tested to see if they could successfully grow retinal tissue grafts from the human cells.

They then performed transplanted the tissue to monkeys suffering from RP.

One of the key challenges using this approach has been the new tissue forming connections.

After transplantation, not only do the cells need to mature into the different types of light-sensitive retinal cells – the rods and cones – they also need to be able to 'wire themselves in' to the existing network of support cells.

The team found that the new tissue made a number of new connections as the cells matured.

Although more research is needed to test the safety of the technique before it can be used in a human trial, the team have demonstrated it is possible to grow retinal tissue from stem cells and it can develop into mature cells in the retina.

In addition, they add that the two monkey models developed in their study could prove valuable to future studies in RP.

The authors write: 'Although this was an introductory study of hESC-retina transplantation using primate models, we were able to characterize the maturation process of hESC-retinas in detail.

'The results of the present study demonstrate the potential utility of these models in further studies of graft optimization or surgical conditions.

'These methods may also facilitate greater understanding and further insights from human studies.'

Stem cells are increasingly being investigated as a potential treatment for sight-threatening eye conditions.

In September 2014, Dr Masayo Takahashi at RIKEN led a team to develop the world's first stem cell retinal graft for AMD. 

However, unlike the current study, the tissue was grown from the patient's own skin cells, taken from their arm.

The graft was then transplanted into the eye of the 70-year-old woman with AMD, who is reportedly still undergoing follow-up observations as part of the trial.

Earlier this year, eye surgeons in London carried out another world first, successfully transplanting hESC-derived retinal tissue to a patient with AMD. 

Source : http://goo.gl/d1NToH