This is Steve Ember. And this is Bob Doughty with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in Science.
Today, we tell about the disease diabetes.
The World Health Organization estimates that as many as one-hundred-twenty-million people have the disease diabetes. Diabetes is the name for several diseases with one thing in common: there is too much glucose, or sugar, in the blood. The disease develops when the body does not produce enough insulin or produces no insulin. Or the disease develops when the body cannot use insulin.
Insulin is a hormone that is necessary to change sugar, carbohydrates and other food into energy. In healthy people, the body changes food into a sugar, called glucose. Glucose is the source of fuel for the body. When food is changed into glucose, it enters the bloodstream and is taken to all parts of the body to feed muscles, organs, and tissue.
When the body senses that there is too much glucose in the blood, it sends a signal to the pancreas. The pancreas is the organ that produces insulin. The pancreas sends insulin into the bloodstream. The insulin lowers the level of blood sugar by letting it enter cells. Insulin helps muscles, organs and tissues take glucose and change it into energy.
That is how the body operates normally, in most people. Diabetes is present when too much glucose remains in the bloodstream and does not enter cells. If the amount of glucose in the blood remains too high, the body begins showing signs of diabetes. Over time, the disease can cause blindness, kidney disease, and nerve damage. High glucose levels in the blood also can lead to strokes and heart disease. Blood circulation also is affected, especially in the legs. Often, victims of diabetes must have a foot or even a leg removed because of blood circulation problems linked to the disease.
There are two main kinds of diabetes, Type One and Type Two. Between five and ten percent of those suffering from diabetes have Type One. It usually begins before the age of thirty in people who are thin.
It is most commonly found in children under the age of sixteen. It is caused by the body's defense system. The bodies of Type One diabetes victims produce a substance that attacks and kills some cells in the pancreas, blocking the production of insulin. These cells are called islet cells. Scientists are not sure why this happens. They believe there may be a number of causes.
They include viruses, the presence of insect-killing pesticides in the environment or molecules known as free radicals. Free radicals are produced as part of normal chemical processes in the body. In people with diabetes, too many of these free radicals are present in the body. Scientists are not sure which of these causes is the most important to the development of Type One Diabetes.
People suffering from Type One diabetes must carefully control their diets. And they must exercise often. People with this kind of diabetes almost always require insulin injections. Patients must always know their blood sugar levels. When the level of glucose in the blood is too high, they must inject insulin into their bodies to reduce the amount of glucose. The patients must inject insulin every day, often several times a day. In most developed countries, insulin is easy to get and does not cost much money. However, doctors believe that these injections can cause long-term problems. They believe that the injections cause levels of glucose to change often.
Scientists believe that many quick changes in glucose levels can, over time, result in damage to the body. This damage can be blindness, kidney failure, heart disease, or poor blood flow in the body.
Type One Diabetes also is known as juvenile onset diabetes, because it usually starts in children or young people. Scientists believe it is the form of the disease that they will most likely be able to cure some day. Among the treatments being studied is a vaccine to prevent the disease. A vaccine is injected into the body or taken by mouth in the form of a pill.
Another possible treatment for Type One Diabetes is placing new islet cells into the pancreas to help it make insulin. Doctors have been transplanting islet cells into diabetes patients for several years. However, these healthy islet cells have failed to permanently replace the need for insulin injections.
Scientists also are studying special cells called stem cells to treat the disease. Stem cells develop into all the different kinds of cells in the body. Scientists believe that stem cells from unborn babies could be used to treat diabetes and other diseases. However, it would be a long time before such treatment is possible.
While some scientists continue to seek ways to cure Type One Diabetes, others are searching for easier ways to get insulin into the body. New devices are being developed that could replace injections. One device being tested is an inhaler.
This device would permit patients to breathe insulin into their bodies. The insulin is in the form of a powder, like dust. When the insulin reaches the lungs, it quickly moves into the bloodstream to reduce glucose levels.
Type Two Diabetes generally is found in people more than forty years old. Most of these people are too fat. Their bodies can not produce enough insulin to reduce the levels of glucose in their blood. Or, their bodies do not react correctly to the action of insulin.
Type Two Diabetes is more complex than Type One. Experts say Type Two Diabetes is really a group of diseases, with many possible causes. Scientists see little hope in developing a cure for this kind of diabetes. Instead, they are searching for better ways to control it. Many people suffering from the disease can control it with exercise and by carefully controlling their diet. Also, many of them do not need to inject insulin into their bodies. Type Two Diabetes is sometimes called non-insulin dependent. Still, patients often need drugs to treat the disease.
There are a number of drugs that can be used. However, many of them can cause other problems. One of the drugs is called sulfonylurea. It has been used for many years to help the pancreas make more insulin. But after several years, the drug loses its effects on the pancreas. Also, it can cause patients to gain weight.
The drug metformin appears to be more effective. It lowers the amounts of glucose in the blood. It does this by helping the body make better use of its own natural insulin. It does not cause weight gain. However, metformin can be dangerous for people with damaged kidneys. It should not be used by people who drink large amounts of alcohol, or those with kidney, liver or heart problems.
Genes seem to be more important in the development of Type Two Diabetes than in Type One. About ninety percent of those with Type Two Diabetes have parents and ancestors who also had the disease. In recent years, scientists have found several genes that may be linked to Type Two Diabetes. Some of these genes also are linked to extreme overweight, known as obesity. About eighty to ninety percent of people with Type Two Diabetes are obese. Often doctors do not discover that patients have diabetes until one of the disease's serious results is found. For example, a doctor examines a patient suffering several health problems.
The doctor carries out tests and finds the problems are the results of poor kidney performance. Tests then show the patient is suffering from diabetes, which can cause kidney problems and even failure.
Although great progress has been made in the treatment of diabetes, it is still widespread and threatens the health of millions of people. Scientists hope that their research will lead to a cure for Type One Diabetes. And they hope they can find new ways to improve treatment of Type Two Diabetes. In future programs we will discuss new developments in diabetes research as they are reported.
This SCIENCE IN THE NEWS program was written by Oliver Chanler. This is Steve Ember. And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.