A team of vascular biologists at the University of Leeds have found that a naturally occurring substance known as C-peptide protects blood vessels from the damaging effects of insulin.
Their report is published in Diabetologia, the journal of the European Association for the study of Diabetes.
Lead researcher, Dr Karen Porter from Leeds Institute of Genetics, Health and Therapeutics (LIGHT) explained, ‘The hormone insulin is given to diabetes patients to control blood sugar levels, but over time it can cause the vessels that supply blood to the heart to become blocked. As a consequence, people with diabetes are more prone to heart attacks and even if they undergo a heart bypass operation the new veins grafted into the heart are more likely to become blocked, leading to further damage.
‘We found that administering insulin with C-peptide - which is released naturally in partnership with insulin in healthy people - appears to protect blood vessels against this damage.’
The researchers found that insulin on its own causes some cells in blood vessels to grow more than they should, which would lead to narrowing of the passageway used by the blood to get to the heart.
Amazingly when C-peptide was given along with insulin, as happens in people without diabetes who release both together, the excessive growth and movement of cells was completely stopped.
‘It used to be thought that the C-peptide had no function and therefore it was not incorporated in man-made replacement insulin, but our work indicates this is not the case,’ said Dr Porter.
‘Our work suggests that a combination of insulin and its partner C-peptide may provide a more effective treatment than insulin alone in controlling some of the cardiovascular complications associated with diabetes.’