20 March 2011
Raised levels of certain amino acids in the blood could flag up the possibility of someone developing diabetes later in life, researchers in the US have discovered. The finding provides another potential predictor for the risk of developing diabetes - along with obesity and abnormal blood sugar levels - and opens new avenues to investigating the fundamental biochemistry of how diabetes develops.
A team from Harvard University in Boston, led by Robert Gerszten and Thomas Wang, screened blood samples from people who had enrolled in a major medical project, called the Framingham Heart Study, in the early 1990s. Of 2,400 participants, around 200 developed type 2 diabetes during the following 12 years. The research team used mass spectrometry to analyse metabolites in the blood of the people who went on to develop diabetes, compared with a control population in the study, with similar characteristics but who did not develop the condition.
"We now need to figure out what is the cart and what is the horse"
- Robert Gerstzen
The scientists discovered that five amino acids - isoleucine, leucine, valine, tyrosine and phenylalanine - were likely to be at increased levels in the people who went on to develop diabetes, up to 12 years later, even though they had no other signs at the time. In particular, elevated levels of isoleucine, phenylalanine and tyrosine pointed to greater risk. Individuals with the highest level of these three metabolites had a four- to five-times greater risk of developing diabetes than those with the lowest levels.
The findings were confirmed by screening blood samples of participants in another long-term study in Sweden, some of whom also developed diabetes later in life.
Gerszten says that identifying people with higher risk of developing diabetes would allow intervention at an early stage to prevent or delay the condition, such as radical changes in lifestyle or the use of drugs.
'We now need to figure out what is the cart and what is the horse,' Gerszten says. 'In other words, are these early markers of the disease, or do they participate in the causal pathway that leads to the condition? We are currently investigating this.'
'This is some way off being considered a routine diagnostic test,' says Iain Frame, director of research at the charity Diabetes UK. 'But it nicely highlights the potential use of surrogate biomarkers in helping us to not only identify those at high risk of developing type 2 diabetes, but also to help shed light on the role of certain metabolites in promoting development of the disease.'