Link Identified between Inflammation and Depression

It is well established that people with both type-1 and type-2 diabetes have an increased risk of developing depression, a debilitating mental health disorder with potentially serious consequences, but the causes remain poorly understood.

Depression in type-1 diabetes patients is associated with higher levels of the inflammatory protein galectin-3, which is a key protein involved in promoting inflammatory immune system responses that are needed to repair tissue damage throughout the body, in response to injury or disease.

Scientists at Lund University (Lund, Sweden) and their colleagues carried out a cross-sectional study that included 283 type-1 diabetes (T1D) patients (56% men, age 18-59 years, diabetes duration ≥1 year). Depression was assessed by Hospital Anxiety and Depression Scale depression subscale. Blood samples, anthropometrics and blood pressure were collected, supplemented with data from medical records and the Swedish National Diabetes Registry.

Galectin-3 was analyzed using a commercial human DuoSet enzyme linked immunosorbent assay (ELISA) and supplementary ancillary kit. The ELISA analysis was performed and absorbance was measured at 450-580 nm in a FLOUstar optima plate reader. Concentrations of unknown samples were calculated using a four parameter logistic regression curve. The intra-assay coefficient of variation for the analysis was 4.3%. Galectin-3 levels equal to or greater than. 2.562 µg/L, corresponding to the 85th percentile, was defined as high galectin-3.

The scientists found that the median (quartile1, quartile3) galectin-3 was 1.3 µg/L (0.8, 2.9) for the 30 depressed patients, and 0.9 µg/L (0.5, 1.6) for the 253 non-depressed. Depression was associated with high galectin-3 in all the 283 patients (Adjusted odds ratio (AOR) 3.5), in the 161 men (AOR 3.4), and in the 122 women (AOR 3.9). HbA1c, serum-lipids, serum-creatinine, blood pressure, obesity, smoking, physical inactivity, cardiovascular complications, and drugs (antihypertensive, lipid lowering, oral anti-diabetic drugs, and antidepressants) were not associated with high galectin-3.

The authors concluded that their study was the first to show an association between depression and galectin-3. Depression was the only explored parameter associated with high circulating galectin-3 levels in 283 T1D patients. High galectin-3 levels might contribute to the increased risk for Alzheimer’s disease, cardiovascular and all-cause mortality observed in persons with depression. Potentially, in the future, treatment targeting galactin-3 might improve the prognosis for patients with high galectin-3 levels. The study was published on May 14, 2018, in the journal Endocrine Connections.

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