The Promise of Stem Cells
Diabetes has been diagnosed in about 11 million people in the United States. People with diabetes do not properly produce insulin, which is necessary to regulate sugars and starches. While pancreas and islet transplants end reliance on insulin injections for some, there is a shortage of donors. In the United States, there are more than 30,000 new cases of type 1 diabetes each year but only 3,000 potential donors whose pancreases are suitable. Currently, there is no cure for diabetes.
Stem cells offer promise to those with diabetes. If stem cells could be cultivated to become cells that produce insulin, they could solve the problem of donor shortage. If a stem-cell therapy could be developed, it would also help relieve diabetes-related diseases of the kidneys, eyes, nerves, and veins.
To treat diabetes, stem cells need to be cultivated into insulin-producing cells. Once that has been accomplished, researchers expect to transplant stem cells that have been cultivated into insulin-producing cells into diabetic patients. Currently, those who receive transplants must take drugs that suppress the immune system. If a person’s own stem cells could be cultivated and used for transplant, those drugs would not be needed. Ultimately, researchers hope to cure diabetes.
Cardiovascular diseases affect nearly 62 million people and is the number-one cause of death in the United States.
Stem cells offer hope to those with heart disease because they might be able to replace damaged cardiac muscle or stimulate the growth of new heart-muscle cells from existing progenitor cells. Because natural regeneration of heart muscle is very inefficient, those who now suffer from a heart attack, from congenital heart disease, or from congestive heart failure have few treatment options. And while heart transplants potentially could help more patients, the supply of organs is limited.
Clinical trials using a patient’s own stem cells, derived from bone marrow, have already been carried out in United States and Europe, but few grafted cells survive and the benefits are very modest. Current work by stem cell researchers at the University of Minnesota focuses on identifying cardiac progenitor cells and devising new methods to create cardiac progenitor cells from embryonic stem cells or induced pluripotent stem cells.
Liver diseases such as cirrhosis and hepatitis affect 25 million people in the United States and represent the seventh most common cause of death in the United States. Liver transplantation can help some but there is an extreme shortage of transplantable organs. Although more than 18,000 people currently await liver transplantation in the United States, only 5,000 organs will be transplanted in the next year.
Stem cells offer promise both to people born with liver problems and to those who develop liver disease later in life. Those born with liver disease caused by a genetic error potentially could be treated by a relatively small amount of liver cells. These cells could relieve the symptoms of liver disease or the genetic error could potentially be corrected by gene therapy.
In cases of acute liver failure in adults, stem cell therapies might be used to support the liver for a period of time. If the therapy works, patients’ livers would gain time to recover. There are indications that some forms of viral hepatitis might be treated with stems cells as well.
Researchers at the U are exploring using stem cells in a liver-support device, repairing genes with liver stem cells, and infusing stem cells into liver portal veins. A team focusing on liver disease has made progress in the areas of liver support and gene repair. Some disease treatments may be limited to support but other diseases might be cured with stem cells. Applicable treatments are still five or more years in the future; at this time, there are no plans for human clinical trials.
There’s a mistake in some of these genes. And if we could rewrite that code, Alzheimer’s, Parkinson’s, liver conditions—it would work for all of them. —Jakub Tolar, MD, PhD
University of Minnesota researchers are focusing on finding novel treatments for Parkinson’s disease using stem cells. Parkinson’s disease, which affects a million people in the United States, often begins as a tremor in the hands or feet. Patients later develop trouble with walking and other daily activities as control over the body erodes. While some patients manage their symptoms, there is no cure for Parkinson’s disease.
Stem cells offer hope to those with Parkinson’s disease, which is caused by the loss of nerve cells in the brain. These nerve cells produce a neurotransmitter called dopamine. If stem cells can be cultivated to become these dopamine-producing nerve cells, researchers believe that they could replace the lost cells.
Other disorders of the brain or nervous system that might be treated with stem cells include stroke, ALS (Lou Gehrig’s disease), multiple sclerosis, Huntington’s disease, Alzheimer’s disease, and spinal cord injuries.
The treatment method being explored is transplanting appropriate cells into the target sites of the brain that need dopamine. Because Parkinson’s disease is caused by the failure of one type of cell to do its job—the dopamine-producing cells in the thalamus—Parkinson’s is believed to be one of the most likely beneficiaries of stem cell research.
Treatments for humans are still years away. At this time, it is hard to pinpoint when human clinical trials might begin, as complex research often encounters unexpected hurdles. With current progress in stem cell research, however, researchers believe they may one day cure Parkinson’s disease.