Newer biomarkers for insulin resistance include adipocytokines (chemicals produced by fat tissue), which include adiponectin, ghrelin, leptin, and resistin. The hormones pancreatic polypeptide and glucagon-like peptide 1 (GLP-1) play a role in digestion and satiety. These factors can be used in the evaluation of obesity, the risk for metabolic syndrome, and the risk for type 2 diabetes.
• Leptin and resistin make tissues more resistant to insulin, thereby increasing the risk for diabetes.
• Adiponectin does the opposite, by sensitizing the tissues to insulin. Falling adiponectin levels mark the first stage of progression to diabetes.
• Ghrelin lets us know that we feel full. • Pancreatic polypeptide (PP) is a hormone released after eating. It slows the movement of food through the gut and causes a release of hormones and enzymes that help digest the food. It also lets us know we are full. Reduced levels are associated with obesity.
• Glucagon-like peptide (GLP-1) is released proportionally to calories ingested. It also helps to decrease appetite. As patients progress toward diabetes, other markers often rise. These include inflammatory markers such as:
• hs-CRP (high-sensitivity C-reactive protein) • IL-6, IL-8 (interleukin-6 and -8) • Tumor necrosis factor alpha (TNFα) • Plasminogen activator inhibitor type 1 (PAI-1)
Other markers include elevated uric acid, ferritin, fibrinogen, and low red cell magnesium levels.