New Technology Makes Diagnosing Serious Geriatric Diseases As Easy As Measuring Blood Sugar

As the elderly population grows, so does the societal cost of managing age-related illnesses, which is driving a surge in interest in early disease detection. Among the diagnostic techniques under investigation, scientists are particularly focused on the role of glutamine as a potential marker for geriatric diseases. They've observed notable changes in glutamine levels in the cells and blood of patients with severe conditions like cancer, diabetes, and dementia compared to healthy individuals. Glutamine, an amino acid present in blood, is crucial for protein synthesis and energy production in cells. Its quick changes in specific situations make it an effective biomarker for both treating and early identifying diseases. Active research is underway to understand how the body metabolizes glutamine to potentially diagnose metabolic and degenerative diseases, including the treatment of cancer by blocking glutamine metabolism. Until now, measuring glutamine levels required specialized, costly equipment like amino acid analyzers, or relied on low-cost research kits that necessitated time-consuming pre-treatment steps, both of which were less than ideal.

A new technology developed by researchers at the Korea Institute of Science and Technology (KIST, Seoul, Korea) can accurately and rapidly measure glutamine levels without relying on complicated methods or expensive analytical equipment. The team utilized the concept of 'ligand-induced protein assembly' to create a sensor protein for measuring glutamine concentrations in blood. They split a glutamine-binding protein into two synthetic proteins that can then bind to a sample. This new sensor is named Q-SHINE, derived from the symbol Q for glutamine and the word SHINE to indicate brightness or glowing.

Tests revealed that the Q-SHINE sensor is highly specific, not reacting to other structurally similar amino acids like glutamic acid and D-glutamine. It can detect glutamine at concentrations as low as 1 micromolar (µM), which is 20 times more sensitive than the enzymatic assays commonly used in research kits. Additionally, this sensor protein can be easily produced in E. coli bacteria, allowing for glutamine analysis on par with high-cost analytical instruments. Moreover, the Q-SHINE sensor has been successfully used to monitor real-time changes in glutamine concentrations within living cells, including both the cytoplasm and mitochondria. Specifically, the team verified variations in glutamine levels between cancer cells and normal cells, a finding that could potentially speed up the development of cancer treatments aimed at inhibiting glutamine metabolism.

"The Q-SHINE sensor developed by KIST will enable easy monitoring of glutamine concentration, similar to the self-monitoring of blood glucose by diabetics," said Dr. Seo, Moon-Hyeong of KIST. "If used for glutamine metabolism research, it will greatly contribute to early diagnosis and identification of causes of severe geriatric diseases such as cancer, diabetes, and dementia, as well as development of cancer drugs that regulate glutamine metabolism."

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