Researchers identify biological markers for diabetes

By Mark Wheeler

In the first large-scale, multi-ethnic study of its kind, UCLA researchers have confirmed the role played by three molecules, known as cytokines, in causing Type 2 diabetes. These molecules have been identified by scientists as early biological markers that may be used to more accurately predict future diabetes in healthy individuals.

Reporting in the Aug. 15 issue of the journal Archives of Internal Medicine, a team led by principal investigator Simin Liu, professor of epidemiology and medicine with a joint appointment at the UCLA School of Public Health and the David Geffen School of Medicine, have identified three inflammatory cytokines, or messenger molecules — tumor necrosis factor-alpha (TNF-á), interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP) — that may be one of the causes of Type 2 diabetes, which afflicts roughly 7% of the U.S. population.

The study identified 1,600 new cases of diabetes and measured the blood markers before the subjects involved developed the disease. Participating in the study were 40 clinical centers nationwide and 12 authors from several institutions, including Liu’s former affiliation, Brigham and Women’s Hospital and Harvard Medical School.

Type 2 diabetes is the most common form of diabetes and accounts for about 90-to-95% of all diabetes cases.

People with this condition produce insulin, but their bodies do not make enough of it or can’t use it effectively. Low-grade, chronic inflammation of the body, reflected by elevated levels of inflammatory cytokines in the blood stream, may promote insulin resistance in the liver, muscles and the vascular endothelium cells, the layer of thin, flat cells that lines the interior surface of blood vessels. Inflammation can last for years before leading to Type 2 diabetes, hypertension or cardiovascular disease.

A blood test that looks for high levels of inflammatory cytokines could serve as an accurate predictor of diabetes in still-healthy people, years ahead of traditional risk-factor indicators such as obesity or insulin resistance. The finding also has implications for cancer research, according to Liu, since people with diabetes are at greater risk of developing breast and colon cancers.

"Identifying these markers by a simple blood test well before a disease begins not only can help improve mechanistic understanding of the disease but also offer alternatives to lifestyle — hitting an optimal balance of nutrition, for example, and engaging in more exercise — relatively simple things that can prevent disease," Liu said.