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Islets from Stem Cells - New Treatment Opens Wide Hope for Diabetics

Islets from Stem Cells-- New Treatment Opens Wide Hope for Diabetics

The ultimate goal, which has so far proved elusive, is a cure for diabetes, which could potentially be available for both types of diabetes through stem cell research.

WHAT ARE STEM CELLS?

Stem cells are a form of cell that is yet to develop a specific set of traits. However, what stem cells have in abundance is the potential to develop into a number of different forms.

WHAT IS STEM CELL RESEARCH?

Stem cell research covers the scientific study of these stem cells. Stem cell research allows researchers to grow specific varieties of human cells in the lab and research how they behave and interact under different conditions.

Stem cells open up a wide spectrum of diabetes research possibilities. In one example of diabetes stem cell research, researchers took cells from human intestine cells and disabled a gene which enabled the cells to produce insulin. In theory, embryonic stem cells could be cultivated and coaxed into developing into the insulin-producing islet cells of the pancreas.

WHERE DO STEM CELLS COME FROM?

Stem cells for the treatment of diabetes are able to come from a variety of sources.

These include foetal tissue from:

Embryos

The placenta

Umbilical cord

Bone marrow

Blood cells

Teeth

A new technique that grows insulin-producing cells and can protect them from immune attack after they are transplanted may offer new hope for treating some people with diabetes.

Recent advances in medical science have allowed islet transplantation – replacement of destroyed beta cells using cells harvested from donors.

Islets are cell groups within the pancreas which are comprised of beta cells – the cells that make insulin, the hormone that regulates blood glucose levels.

ISLET CELLS AND DIABETES

Diabetes is actually a group of diseases characterized by abnormally high levels of the sugar glucose in the bloodstream. This excess glucose is responsible for most of the complications of diabetes, which include blindness, kidney failure, heart disease, stroke, neuropathy, and amputations. 

Type 1 diabetes, also known as juvenile-onset diabetes, typically affects children and young adults. Diabetes develops when the body's immune system sees its own cells as foreign and attacks and destroys them. As a result, the islet cells of the pancreas, which normally produce insulin, are destroyed. In the absence of insulin, glucose cannot enter the cell and glucose accumulates in the blood.

 Type 2 diabetes, also called adult-onset diabetes, tends to affect older, sedentary, and overweight individuals with a family history of diabetes. Type 2 diabetes occurs when the body cannot use insulin effectively. This is called insulin resistance and the result is the same as with type 1 diabetes—a build up of glucose in the blood.

Researchers have turned their attention to adult stem cells that appear to be precursors to islet cells and embryonic stem cells that produce insulin.

HOW DO ISLET CELL TRANSPLANTS WORK?

One treatment devised to end that reliance involves transplanting donor islets into diabetics, but the process is complicated by several obstacles, including a shortage of donors.But in some cases, Islets also often fail to connect with blood supply, and even when they do, like other transplants, they can come under attack by the recipient's immune system, which views the cells as invaders.As a result, patients have to take drugs that suppress their immune systems, protecting their transplant but potentially exposing the rest of their body to illness.

Usually, transplant patients are given islet cells from as many as three donor pancreases. Just like healthy pancreatic beta cells, the donor cells produce insulin in a normal way. This can help to achieve blood glucose stability and lower the amount of insulin required.

Furthermore, in some cases, beta cell transplants may be so effective that the patient receiving transplants can stop insulin administration entirely.

A NEW SOURCE FOR ISLETS FROM STEM CELLS

In a bid to overcome some of these challenges, a team looked to find another source for islets, by coaxing induced pluripotent stem cells (iPS) to produce what the team called HILOs, or human islet-like organoids.

These HILOs, when grown in a 3D environment mimicking the pancreas and then turbocharged with a "genetic switch", successfully produced insulin and were able to regulate blood glucose when transplanted into diabetic mice.

"In the past, this functionality was only achieved after a month-long maturation in a living animal," said Ronald Evans, director of the Gene Expression Lab at the Salk Institute for Biological Studies.

"This breakthrough allows for the production of functional HILOs which are active on the first day of transplantation, placing us closer to clinical applications," Evans, who led the study, told AFP.

Having found a potential way to solve the supply chain problem, the scientists then sought to tackle the issue of immune rejection.

They focused on something called PD-L1, a so-called checkpoint protein that is known to inhibit the body's immune response.

"Normally, human cells placed in a mouse would be eliminated within a day or two," said Evans.

"We discovered a way to create an immune shield that makes human cells invisible to the immune system."

While HILOs transplanted into mice without the PD-L1 protection gradually stopped functioning, those induced to express the protein were shielded and continued to help diabetic mice regulate their blood glucose for more than 50 days.

Being able to grow insulin-producing cells and protect them from attack "brings us much closer to having a potential therapy for type-1 diabetic patients," Evans said.

Around 422 million people worldwide were living with diabetes by 2014, according to the World Health Organization, a figure that includes both type-1 and type-2 diabetes.

Islet transplantation is generally considered as a treatment for type-1 diabetics, whose disease is the result of an auto-immune response.

Evans cautioned that the research, already a decade in the making, was still years from being able to treat diabetes in humans.

"To advance HILOs into the clinic, we need to confirm that they work in other animal models, including primates, as well as do longer-term studies in mice," he said.

He hopes that human studies of the technique will be possible in two to five years.

"This is a hard-to-manage disease and insulin is not a cure," he added, noting that 1.6 million children and teenagers are living with type-1 diabetes in the United States alone.

"Good science is not just a discovery -- it can enrich the world and give hope to those who live with disease."

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