Module 2 Lesson 6 - 4

Blood Glucose Imbalances

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Read pages 457 - 459

Among your friends, relatives, and teachers, you likely know someone who has diabetes mellitus. This is a disorder in which blood glucose levels are abnormally high because the pancreas does not produce enough insulin, or the body cells do not respond to the insulin that the body produces. Doctors usually use the full name rather than diabetes alone to distinguish it from diabetes insipidus, which has nothing to do with blood glucose levels. Do you remember what happens in that disorder? Diabetes insipidus involves an insufficient level of ADH.

In diabetes mellitus, a lack of insulin causes blood glucose levels to rise sharply (spike) after meals and to remain high for long periods. This is called hyperglycemia. With too much insulin, glucose levels plummet and the person has hypoglycemia (a hypoglycemic episode).

Diabetes usually is grouped as Type 1 diabetes (also called insulin dependent / juvenile diabetes) or Type 2 diabetes (also called insulin independent / adult onset diabetes). Untreated glucose imbalances lead to many symptoms and can result in blindness, kidney failure, nerve damage, and severe infection in the limbs, which may lead to amputation. Several medical technologies have been developed to help diabetics deal with their conditions.

A Comparison of Type 1 Diabetes with Type 2 Diabetes

Feature	Type 1 Diabetes	Type 2 Diabetes
Cause	Autoimmune disease in which antibodies destroy beta cells in pancreas and little or no insulin is produced	Receptors on target cells do not respond to the insulin produced; insulin resistance develops
Onset	Rapid	Gradual
Age of Onset	Childhood	Adulthood, although more cases in young people recently
Predisposition	None known	Obesity increases significantly the risk of development of diabetes
Insulin Production	Very little or none	Insulin produced but ineffective
Immediate Symptoms	Fatigue/low energy, glucose in urine, increased volume of urine, increased thirst, weight loss, smell of nail polish (acetone) on breath	Fatigue/low energy, glucose in urine, increased volume of urine, increased thirst, no smell of nail polish on breath
Long-Term Effects	Blindness, kidney failure, nerve damage, gangrene, increased risk of heart attack and stroke	Blindness, kidney failure, nerve damage, gangrene, increased risk of heart attack and stroke
Treatment	Insulin injections, islet transplantation	Control diet, lose weight, increase exercise, drugs to decrease insulin resistance, and insulin injections

If the beta cells are destroyed by an autoimmune disease and little or no insulin is produced, consistently high blood glucose levels result in Type 1 diabetes. Left untreated, life-threatening consequences result. Regular glucose monitoring and insulin injections are the only treatment for Type 1 diabetes. Insulin cannot be taken in pill form because the digestive system would break it down before it could be absorbed. (Insulin is a protein hormone.)

If the pancreas sends out insulin but the body cells ignore it (called insulin resistance), Type 2 diabetes results. Being very fat (obese) increases the inability of the cells to respond to insulin. The obvious treatment is to lose weight. Controlling diet and regular exercise can persuade the cells to respond to the insulin. In some cases, drugs must be used.

Sometimes when the blood glucose levels dip below normal, hypoglycemia occurs in people with diabetes. The person becomes anxious, nervous, develops shakiness, and has a feeling of weakness. Continued hypoglycemia causes the brain to become disoriented and may progress to unconsciousness and possibly death. If symptoms are recognized quickly, hypoglycemia is treated easily by eating candy or injecting glucagon.

Medical technologies for monitoring with diabetes mellitus have progressed from glucose dipsticks to digital glucose monitors. Regulation of insulin levels has progressed from syringes with insulin to insulin pens or insulin pumps. Hard-to-manage cases can be treated with islet transplants.

Watch and Listen

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View the following segment of Biologix-11 on Diabetes Mellitus (12 minutes).

Islet Transplantation

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A research team at the University of Alberta has developed a procedure called the Edmonton Protocol that helps people who have difficulty managing Type 1 diabetes undergo an islet transplant procedure. Read page 466 in your textbook, which is an interview with Dr. Edmond Ryan, Medical Director of the University of Alberta Clinical Islet Transplant Program.

In the Edmonton Protocol, pancreatic islets from a deceased donor are isolated and transplanted into another person. Islet transplant patients must wait for the treatment until donated organs become available. Other potential sources of islet cells can be from a living donor, animal sources, or stem cells. Because Type 1 diabetes is an autoimmune disease, rejection of the transplanted islets is always an issue. Further research into stem cells and gene therapy are important to successful islet cell transplantations that will lead to long-term insulin-independence.

Blood Sugar Regulation Summary

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