Microchip Technology Could Improve Type 1 Diabetes Diagnosis

Nancy A. Melville

July 13, 2014

New microchip technology could prove effective for diagnosing type 1 diabetes at the point of care with just a finger-prick sample of blood, offering a potentially valuable improvement over time-consuming conventional testing, according to novel research published online July 13 in Nature Medicine.

The technology could help streamline diabetes testing just as a troubling shift is occurring with the prevalence of the disease itself, lead author Brian J. Feldman, MD, PhD, assistant professor of pediatric endocrinology and the Bechtel Endowed Faculty Scholar in Pediatric Translational Medicine at Stanford University, California, told Medscape Medical News.

"It has long been held that if a patient were young and had diabetes, a clinician could be pretty confident that they were dealing with type 1 diabetes, and if the patient was older and overweight, the likelihood was type 2 diabetes, but with this surge in childhood obesity, we're now seeing more children with type 2 diabetes, and, much more inexplicably, we're also seeing a dramatic increase of type 1 diabetes in adults," said Dr. Feldman.

"So basically, these 2 distinct populations have dramatically overlapped, and prior assumptions about the diabetes epidemiology are becoming obsolete."

Enter the heightened need for not just more diagnostic testing but improved methods. Current lateral-flow assays and ELISA fail to meet acceptable sensitivity and specificity in identifying the difficult-to-detect insulin-specific autoantibody biomarkers of type 1 diabetes, and radioimmunoassay is cumbersome and labor intensive, requiring full blood draws that can take days to weeks to yield results, the authors explain.

But despite the shifting diabetes trends, the majority of diagnoses are still made based on clinical characteristics and symptoms, endocrinologist Alvin C. Powers, MD, professor of medicine, molecular physiology, and biophysics and director of the Vanderbilt Diabetes Center at Vanderbilt University School of Medicine, Nashville, Tennessee, told Medscape Medical News.

However, he conceded that diagnostic testing can be useful in the niche of uncertain cases: "With either adolescents or young and middle-aged adults where there are clinical features suggestive of both type 1 and type 2 diabetes, it would be helpful to be able to distinguish [between] those," explained Dr. Powers,.

"But this is not a test where you necessarily need to have a result in 10 minutes," he noted. "If you have the result in 1 day or 10 days, it doesn't really change clinical management."

One area where this novel test could potentially be more useful would be in the research setting, he said, stressing that what's being measured here is not new — rather, the technology is an improvement upon previous methods.

Assay May Be Able to Predict Future Risk of Type 1 Diabetes as Well

The new assay, still in the early stages of development, employs innovative microchip technology. Glass plates at the base of the microchip are coated with nanoparticle-sized islands of gold that identify the autoantibodies with intensified, multicolor fluorescence, explain Dr. Feldman and colleagues in their paper.

The assay permits multiplexing of the islet antigens, enabling the detection of 3 autoantibodies simultaneously. In validating the new test's efficacy on blood samples of 39 patients with new-onset diabetes and nondiabetic controls, the researchers found the microchip test and radioimmunoassay to each have the same results — a sensitivity of 100% and specificity of 85% for detecting type 1 diabetes.

In addition to enabling type 1 diabetic patients to get the treatment they need sooner — and allowing those who don't wind up having the disease to avoid unnecessary therapy — the assay could even allow for the monitoring of autoantibody levels for those at risk of type 1 diabetes, Dr. Feldman said.

"If you don't have diabetes and you are found to have 1 autoantibody, you are at a significantly increased risk of developing type 1 diabetes in the future, and if you have 3 or more, you are at a greater than 90% risk," he explained.

Preliminary studies also show that in order to get the full benefit from immune modulation and new antigen-specific therapies for diabetes, time is of the essence. Starting the therapies as early as possible is important for them to be most effective, and even delaying treatment by several weeks can limit their efficacy, Dr. Feldman and his coauthors claim.

"The current platforms for diagnosing diabetes are unable to meet this important emerging requirement and could prevent patients with type 1 diabetes from receiving the maximum benefit from their therapy," they write.

Cost Savings Mean Test Could Be of Use in Developing World

Importantly, the assay is expected to be available at a fraction of the cost of radioimmunoassay, Dr. Feldman noted.

"We are really excited about the [cost advantage], because the radioimmunoassay platform is basically inaccessible to many regions of the globe, where there isn't the technical expertise or the financial resources for the testing," he noted.

"This state-of-the-art development in molecular chemistry will allow for testing that will…be quite easy to set up and operate and will be cost-effective," he added. "We hope to provide access to this important diagnostic test globally, and it is part of our vision that the test will be deployable in a variety of environments."

Dr. Feldman and his colleagues are currently seeking approval from the US Food and Drug Administration (FDA) for approval of the device.

Dr. Powers, who was not involved in the development of this new assay, says it could "have utility in the research arena, as we try to understand what causes type 1 and type 2 diabetes.

"To be clear, what they are measuring here is not new, but it's a technological improvement of how it's measured," he said, and "to be able to very specifically diagnose in a large number of people could be an important use of this."

The work was supported by grants from Stanford's SPARK program, the National Institutes of Health, the National Cancer Institute, the Juvenile Diabetes Research Foundation, Stanford Bio-X, Genentech, and the Child Health Research Institute at Stanford. Stanford University and the authors have filed patents for both the technology and the use of the technology to detect islet cell–targeting autoantibodies with the US Patent and Trademark Office and via the International Patent Cooperation Treaty. Dr. Powers reported no relevant financial relationships.

Nat Med. Published online July, 13 2014. Abstract

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