The islets of Langerhans contains two types of cells – alpha and beta cells, which are responsible for producing insulin. Insulin is required by the body for absorbing glucose from the bloodstream. The carbohydrates we consume are broken down into simpler molecules of glucose in the small intestine.
Glucose is then absorbed by the cells of the small intestine, from where they pass into the bloodstream, which carries them to the different parts of the body. Here, insulin plays an important role by facilitating the absorption of glucose by the cells of the muscles, fat tissues, and liver. It helps liver and the muscle cells store glucose in the form of glycogen, and inhibits the use of fats for energy production. In the absence of insulin or in the case of insulin resistance, the body cells cannot absorb glucose from the bloodstream. This in turn, raises the level of blood glucose, a condition known as hyperglycemia.
What Causes Diabetes Mellitus?
The main causes of this metabolic disorder are not known, though genetics, environmental factors, poor diet, obesity, medications, infections, and a sedentary lifestyle are regarded as some of the possible factors that can be associated with this condition.
There are mainly two types of diabetes mellitus – type 1 and type 2. Type 1 diabetes can be termed as an autoimmune disease, where body’s own immune system attacks and destroys the beta cells of the pancreas. What exactly triggers this autoimmune response is not known precisely, but genetics and environmental factors like viral infections are thought to be some of the important contributory factors.
Genetics can be another important cause, and a person has 10% probability of developing the disease, if a first degree relative of his or her has diabetes. In the case of a viral infection, the viral protein that enters the body resembles the beta cell protein. The immune system starts attacking both the beta cells and the virus, being unable to distinguish one from the other.
However, certain other factors can also play a significant role in the development of this metabolic disorder. T lymphocytes, a type of white blood cells, are responsible for producing the immune factors known as cytokines, that destroy the beta cells of the pancreas. Several proteins like glutamic acid, decarboxylase, insulin, and islet cell antigens act as autoantigens, and stimulate the autoimmune factors.
In type 2 diabetes, insulin is produced by the beta cells, but cells cannot respond to it or utilize it properly. This condition is known as insulin resistance. Sometimes, in response to insulin resistance, excessive insulin is produced by the beta cells. This eventually exhausts them and lowers the production of this hormone significantly.
Many believe that the type 2 diabetes can also be caused by the shortage of insulin or the production of abnormal insulin that fails to produce the desired results. The main risk factors for this condition are, genetics, age, obesity, physical inactivity, certain medications, and any kind of diseases that can damage the pancreas.
The risk of developing this disease rises with advancing age. A sedentary lifestyle or the lack of physical activity can further raise this risk. Obesity is another important factor that can cause this metabolic disorder. In addition to these, stress, hypertension, infections of the pancreas, low intake of proteins and fibers, excessive consumption of refined food, and a high level of serum lipids, cholesterol, and triglyceride can also be associated with this disease.
Symptoms of Diabetes Mellitus
The most common signs and symptoms of diabetes are, frequent urination, excessive thirst, blurred vision, fatigue, nausea, and lethargy. This condition is characterized by hyperglycemia or a high level of blood glucose, and the loss of glucose in the urine. A deficiency of insulin alters energy metabolism, which can cause unexplained weight loss as well.
Type 1 diabetes is treated with insulin, while type 2 diabetes is usually treated with sulfonylureas, alpha-glucosidase inhibitors, biguanides, thiazolidinediones, D-phenylalanine derivatives, and insulin. Diabetes is a complicated disease with no permanent cure, and along with medications, diet and lifestyle modifications, weight control, and regular physical activity are also important to effectively manage this condition.