Transplanted stem cells – hope for people with type 1 diabetes
Eelco de Koning, diabetes expert from the Medical Center of the University of Leiden in the Netherlands, speaks of a milestone. In a phase 1 and phase 2 study, 26 patients received insulin-producing cells grown in the laboratory from human embryonic stem cells.
The research began 20 years ago at Novocell in San Diego. In 2006, insulin-producing cells gradually developed from human embryonic stem cells. It took more than ten years for the first clinical experiments to begin. Today the company is called ViaCyte and works with several clinics – in the USA, Canada and Europe. To protect the cells and to better monitor their activity, the company developed a type of packaging, explains Eelco de Koning.
Cells produced insulin for a year
The bag is connected to the bloodstream. It consists of an artificial membrane and is permeable to various substances. After a year, the doctors checked to see if the cells were active and doing their job. The result was noteworthy. The cells responded to a sugary liquid meal with increased insulin production.
“Overall, this is a significant step, in fact one of the first reports to describe functional survival of the islets generated from stem cells for over a year.”
Barbara Ludwig from the Carl Gustav Carus University Hospital in Dresden conducts research herself with insulin-producing stem cells. She sees important progress in the new results.
“Even if the clinical effect of this transplantation was not yet very pronounced for the individual patient, it definitely shows the high potential of this research direction.”
The patients treated needed 20 percent less insulin. And her sugar level stayed in the target range a little longer than without the transplanted cells. Less insulin and a controlled sugar concentration in the blood always mean less long-term damage and a longer life.
However, Eelco de Koning does not yet want to speak of any real clinical improvement. This comes in the next step, in a phase 3 study:
“Then the question is: How many cells do we have to implant in order to achieve a clinical effect so that patients can significantly reduce their insulin requirements or perhaps even get along without insulin at all?”
Further study should make the cells ready for the clinic
Shortly before ViaCyte from San Diego presented these interim results, the competitor Vertex from Boston surprised with a report about a spectacular individual case. As part of a study, 64-year-old Brian Shelton received insulin-producing cells injected directly into his liver. Allegedly, the cells produced enough insulin to control the man’s blood sugar levels on their own.
Even if this is just a snapshot that describes a single case, the advances give hope for people with type 1 diabetes.
Challenge: Defense reactions by the immune system
But one important question remains unanswered. With both cell therapies, the immune system of the cell recipient has to be slowed down, as in an organ transplant. Without this immunosuppression, the body’s defenses would fight and destroy the insulin-producing cells.
“There are basically two ways around that. Either it is possible to change the cells in such a way that they are not even recognized by the immune system, or the option of so-called cell encapsulation, whereby the cells – as in this case – are packed in a kind of chamber, which, unlike in this study, are not accessible to components of the immune system. ”
At the University Hospital in Dresden, Barbara Ludwig and her team are researching such a well-tolerated therapy for type 1 diabetes. Even after the milestone that has now been reached, there is still a long way to go, but the goal seems to be achievable.