Insulin Resistance Overview

Insulin resistance (IR) is a disease that the body's cells of patients become resistant to the effects of insulin. With IR, the pancreas produces more and more insulin until the pancreas can no longer produce sufficient insulin for the body's demands, and then result in blood sugar rises. IR is a crucial link to the development of metabolic syndrome, type 2 diabetes, possibly cancers, and cardiovascular disease. Furthermore, insulin resistance in the absence of metabolic syndrome criteria is independently related to developing cardiovascular disease. People who are overweight or obese are more likely to occur insulin resistance over time. However, other people who are not overweight may also get insulin resistance.

Generally, insulin resistance develops over a long time and does not lead to obvious symptoms. It can make people feel tired and low in energy, but since most people blame their fatigue on other factors (e.g., lack of sleep), insulin resistance can be ignored for years. There is not an exact cause that leads to IR, but a family history of type 2 diabetes, being overweight (especially around the waist), and being inactive all can increase the risk. Compared with the worldwide population, there is a higher incidence among people of African American, Native American, Latino, and Asian descent.

Overview of insulin resistance pathways

Main Signaling Pathways in Insulin Resistance

MAPK Signaling Pathway

PI3K/Akt Signaling Pathway

Diagnosis of Insulin Resistance

Doctors will use these things to diagnose insulin resistance:

• Questions about the family's medical history of patients.
• Physical exam weighs and checks blood pressure.
• Blood tests.

1. Fasting plasma glucose test. This test measures blood sugar after haven’t eaten for at least 8 hours. This fasting blood glucose level, from 100 mg/dl to 125 mg/dl, shows peoples with insulin resistance.
2. Oral glucose tolerance test. Firstly, candidates will take the fasting glucose test. Then candidates drink a sugary solution. There is possibly a correlation between high blood glucose levels during an oral glucose tolerance test and insulin resistance. Therefore, after two hours, candidates will take the blood test. Generally, blood glucose is 140 mg/dl above after three hours suggesting of pre-diabetes or diabetes.
3. Hemoglobin A1c test. This blood test indicates the average blood sugar level over the past 3 months. A normal level is between 4%-5.6%, a level between 5.7%-6.4% is consistent with prediabetes, and a level of 6.5 percent or greater is typical of diabetes. There is not an exact range that is diagnostic of insulin resistance, but a high blood sugar level—in consideration of risk factors and symptoms—is suggestive of the diagnosis.

Targeted Therapy for Insulin Resistance

Patients not only need medical treatments for IR but also the medical treatment for some complications, including hypertension, heart disease, or high cholesterol, rather than a treatment that controls the insulin and blood sugar levels. Furthermore, medications have been prescribed for insulin resistance, although their effectiveness in controlling the disorder is scant. For example, metformin (Fortamet, Glucophage, Glumetza, Riomet) makes the body more sensitive to insulin and is used for the treatment of diabetes and often for insulin resistance. Thiazolidinediones (also called glitazones), including Avandia (rosiglitazone) and Actos (pioglitazone), are able to improve the body's response to insulin and utilized for treating insulin resistance even without a diagnosis of diabetes. Except for medications, doing exercise and getting a healthy lifestyle are also helpful for treating IR. Doing exercise for at least 30 minutes a day of moderate activity (like brisk walking) 5 or more days a week. If people are not sure how to reach a weight loss goal, they need to ask for professional help. In daily life, patients should have a healthy diet. The diet should contain fruits, vegetables, whole grains, nuts, beans, fish, legumes, and other lean protein.

For research use only. Not intended for any clinical use.