Positive correlation between plasma and cerebrospinal fluid galectin-3 in suicide attempters.

OBJECTIVES

Both depression and suicidal behaviour have been associated with neuroinflammation. Galectin-3 (Gal-3), a protein involved in microglial activation, has been linked to pro-inflammatory cytokines and the severity of depressive symptoms. The extent to which peripheral levels of Gal-3 reflect neuroinflammation is unknown, as is the relationship between Gal-3 and suicidality.

METHODS

Blood and CSF samples were collected from recent suicide attempters and healthy controls. CSF levels of cytokines interleukin (IL)-8, IL-1β, IL-6, and tumour necrosis factor-alpha (TNF-α) were available from a subset of the suicide attempters. The Montgomery-Åsberg Depression Rating Scale (MADRS) was used for the assessment of depression symptom severity.

RESULTS

We found a strong positive correlation between Gal-3 levels in plasma and CSF (r = 0.77, p < 0.001, n = 22). There were no significant differences in Gal-3 between suicide attempters and controls in plasma (n = 16 and 23, respectively) or CSF (n = 13 and 18, respectively). Among suicide attempters, we found a negative correlation between Gal-3 and IL-8 in CSF (r = -0.40, p = 0.01, n = 39). Gal-3 did not correlate significantly with any of the other cytokines.

CONCLUSIONS

Peripheral Gal-3 levels seem to reflect Gal-3 in the central nervous system. Results from this small-scale study do not support the role of Gal-3 in the pathophysiology of suicidal behaviour.