Serum S100B Protein is Associated with Depressive Symptoms in Patients with End-stage Renal Disease

Objectives: Depression is associated with a poorer prognosis in patients with end-stage renal disease (ESRD). Increasing evidence indicates that glial pathology and blood-brain-barrier (BBB) dysfunction are involved in the pathophysiology of depression. S100B, a protein expressed in astro- and oligodendroglia in the human brain is considered a biomarker of depression. Our objective was to investigate the relationship between S100B and depressive symptoms in patients undergoing hemodialysis (HD).

Design And Methods: Seventy-eight Korean patients undergoing chronic HD without significant neurological issues participated in a cross-sectional observation study. Depressive symptoms were assessed with the Beck Depression Inventory-II (BDI-II), and serum S100B levels were measured using blood samples obtained prior to a mid-week HD session.

Results: The mean age of patients was 59.0 years, and the mean dialysis duration was 51.7 months. About 45% of patients undergoing HD met criteria for depression (BDI-II≥20). Serum S100B levels were significantly higher in patients with depression compared with patients without depression (115.1±45.4 vs. 66.1±35.3 pg/mL, p<0.001). S100B (r=0.556, p<0.001) and high-sensitivity C-reactive protein (hs-CRP; r=0.422, p<0.001) and β2-microglobulin (r=0.391, p<0.001) levels were positively correlated with BDI-II scores. A multivariate regression analysis showed that both S100B and hs-CRP were significantly associated with BDI-II scores.

Conclusions: The results showed a close association between S100B and depressive symptoms in patients undergoing HD. However, the mechanisms underlying this relationship are currently unknown and warrant further investigation.