How a tiny patch of skin helped researchers save the life of a young boy battling a deadly disease

 

EB boy

After receiving his new skin, the boy plays on the grounds of the hospital in Bochum, Germany. Credit: RUB

By any standards epidermolysis bullosa (EB) is a nasty disease. It’s a genetic condition that causes the skin to blister, break and tear off. At best, it’s painful and disfiguring. At worst, it can be fatal. Now researchers in Italy have come up with an approach that could offer hope for people battling the condition.

EB is caused by genetic mutations that leave the top layer of skin unable to anchor to inner layers. People born with EB are often called “Butterfly Children” because, as the analogy goes, their skin is as fragile as the wings of a butterfly. There are no cures and the only treatment involves constantly dressing the skin, sometimes several times a day. With each change of dressing, layers of skin can be peeled away, causing pain.

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Hands of a person with EB

Life and death for one boy

For Hassan, a seven-year old boy admitted to the Burn Unit of the Children’s Hospital in Bochum, Germany, the condition was particularly severe. Since birth Hassan had repeatedly developed blisters all over his body, but several weeks before being admitted to the hospital his condition took an even more serious turn. He had lost skin on around 80 percent of his body and he was battling severe infections. His life hung in the balance.

Hassan’s form of EB was caused by a mutation in a single gene, called LAMB3. Fortunately, a team of researchers at the University of Modena and Reggio Emilia in Italy had been doing work in this area and had a potential treatment.

To repair the damage the researchers took a leaf out of the way severe burns are treated, using layers of skin to replace the damaged surface. In this case the team took a tiny piece of skin, about half an inch square, from Hassan and, in the laboratory, used a retrovirus to deliver a corrected version of the defective gene into the skin cells.

 

They then used the stem cells in the skin to grow sizable sheets of new skin, ranging in size from about 20 to 60 square inches, and used that to replace the damaged skin.

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In the study, published in the journal Nature, the researchers say the technique worked quickly:

“Upon removal of the non-adhering gauze (ten days after grafting) epidermal engraftment was evident. One month after grafting, epidermal regeneration was stable and complete. Thus approximately 80% of the patient’s TBSA (total body surface area) was restored by the transgenic epidermis.”

The engrafted skin not only covered all the damaged areas, it also proved remarkably durable. In the two years since the surgery the skin has remained, in the words of the researchers, “stable and robust, and does not blister, itch, or require ointment or medications.”

In an interview in Science, Jakub Tolar, an expert on EB at the University of Minnesota, talked about the significance of this study:

“It is very unusual that we would see a publication with a single case study anymore, but this one is a little different. This is one of these [studies] that can determine where the future of the field is going to go.”

Because the treatment focused on one particular genetic mutation it won’t be a cure for all EB patients, but it could provide vital information to help many people with the disease. The researchers identified a particular category of cells that seemed to play a key role in helping repair the skin. These cells, called holoclones, could be an important target for future research.

The researchers also said that if a child is diagnosed with EB at birth then skin cells can be taken and turned into a ready-made supply of the sheets that can be used to treat skin lesions when they develop. This would enable doctors to treat problems before they become serious, rather than have to try and repair the damage later.

As for Hassan, he is now back in school, leading a normal life and is even able to play soccer.

 

 

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Using stem cells paves new approach to treating a blistering skin disease

Imagine a child not being able to run or jump or just roll around, for fear that any movement could strip away their skin and leave them with open, painful wounds. That’s what life is like for children with a nasty genetic disease called epidermolysis bullosa or EB. The slightest touch can cause their skin to peel off. People with the disease often die in their late teens or early 20’s from skin cancer, caused by repeated cycles of skin wounding and healing.

Now Stanford researchers, funded by the stem cell agency, have found a way to correct the faulty gene and grow healthy skin, a technique that could completely change the lives of children with EB. This new approach, which the researchers call “therapeutic reprogramming”, is reported in the journal Science Translational Medicine

In the study the researchers took skin cells from patients with EB and reprogrammed them to become induced pluripotent stem (iPS) cells that have the ability to become any of the other cells in the body. They then replaced the faulty gene that caused that particular form of EB and then turned the cells into keratinocytes, the cells that make up most of our outer layer of skin. When they grafted these cells onto the back of laboratory mice they grew into normal human skin.

In a news release about the work, Dr. Anthony Oro, one of the senior authors of the paper, says the work represents a completely different approach to treating EB.

“Normally, treatment has been confined to surgical approaches to repair damaged skin, or medical approaches to prevent and repair damage. But by replacing the faulty gene with a correct version in stem cells, and then converting those corrected stem cells to keratinocytes, we have the possibility of achieving a permanent fix — replacing damaged areas with healthy, perfectly matched skin grafts.”

One of the key words in that quote is “healthy”. Because the skin cells that they got from the patient probably already included some that had a skin cancer-causing mutation, the researchers carefully screened the cells to make sure they removed any that looked suspicious.

Oro says tests showed the resulting skin from these iPS cells was very similar to human skin made from normal keratinocytes.

“The most difficult part of this procedure is to show not just that you can make keratinocytes from the corrected stem cells, but that you can then use them to make graftable skin. What we’d love to do is to be able to give patients healthy skin grafts on the areas that they bang a lot, such as hands and feet and elbows — those places that don’t heal well. That alone would significantly improve our patients’ lives. We don’t know how long these grafts might last in humans; we may need some improvements. But I think we’re getting very close.”

Having seen that this works in mice the team are now eager to see if they can replicate their results in people. With CIRM support they have already been working with the Food and Drug Administration (FDA) to pave the way for that to happen. Dr. Marius Wernig, one of the senior authors of the paper, says that focus on patients is driving their work:

“CIRM made sure that we were always keeping in mind the need to translate our results to the clinic. Now we’ve shown that this approach that we call ‘therapeutic reprogramming’ works well with human cells. We can indeed take skin cells from people with epidermolysis bullosa, convert them to iPS cells, replace the faulty collagen 7 gene with a new copy, and then finally convert these cells to keratinocytes to generate human skin. It is almost like a fountain of youth that, in principle, produces an endless supply of new, healthy skin from a patient’s own cells.”