People with both type-1 and type-2 diabetes have an increased risk of developing depression, but the reasons for this remain poorly understood.

Now a new study published in the journal Endocrine Connections finds that depression in type-1 diabetes patients is linked to higher levels of an inflammatory protein known as galectin-3.

The findings suggest that measuring levels of galectin-3 could be useful for diagnosis of depression or perhaps as a new target for treating depression associated with type-1 diabetes.

Galectin-3 is a key protein involved in producing the inflammatory immune system responses that are necessary to repair tissue damage throughout the body in response to injury or disease. However, increased levels of galectin-3 have also been associated with a greater risk of inflammatory disorders such as Alzheimer’s disease or cardiovascular disease.

And although prior research has shown that both depression and diabetes may be linked to increased levels of inflammation in the body, the role of galectin-3 has not been investigated in either condition until now.

For the study, the researchers measured the galectin-3 levels of 283 men and women, aged 18-59, with type-1 diabetes, for at least one year. Incidence of depression in these patients was self-reported and assessed using the Hospital Anxiety and Depression Scale-Depression subscale and possible confounding influences of lifestyle factors including heart disease, smoking or poorly managed diabetes were accounted for in the analysis.

The findings revealed that both men and women with type-1 diabetes and depression had significantly higher galectin-3 levels.

“We found that people with type-1 diabetes and depression had higher galectin-3 levels, yet no other diabetes-related metabolic changes could account for these elevated levels,” said Dr. Eva Olga Melin and colleagues at Lund University in Sweden.

While the findings indicate that galectin-3 levels are associated with diabetes and depression, the study does not show a distinct causative relationship. The researchers now plan to study the link between type-1 diabetes, depression and galectin-3 using larger, long-term studies.

Specifically, they plan to investigate how galectin-3 levels are linked to the increased risk of depression, what inflammatory processes are altered, and whether they can be targeted to treat depression.

“Depression is a common disorder with very serious and debilitating consequences, so these findings suggest that further investigating the role of galectin-3 could lead to improved diagnosis and maybe better treatment outcomes for patients in the future,” said Melin.

Source: Society for Endocrinology