Association of Lipoprotein and Thyroid Hormones With Cognitive Dysfunction in Patients With Systemic Lupus Erythematosus

Abstract

Background: Neuropsychiatric systemic lupus erythematosus (NPSLE) occurs up to 75% of adult SLE patients, and is one of the major causes of death in SLE patients. Cognitive dysfunction is a typical clinical feature of NPSLE, which seriously affects the quality of life of patients. Dyslipidemia and thyroid disease, which were prevalent in SLE patients, both related to the neuropsychiatric disturbances, including significant psychiatric and cognitive disturbance. This study aimed to investigate whether cognitive dysfunction in patients with systemic lupus erythematosus (SLE) was related to the expression of serum thyroid hormone and lipoproteins.Methods: A total of 121 patients with SLE and 65 healthy controls (HCs) at Nanjing Drum Tower Hospital completed a cognitive function test, then 81 SLE patients were divided into high cognition (n=33) group and low cognition group (n=48). The differences in clinical and laboratory tests and the correlations between IgG, IgM, albumin, T3, and T4 levels and cognitive function were analyzed. The enzyme-linked immunosorbent assay was used to determine the serum levels of 4 lipoproteins (APOE, APOA1, IGF-1, and IGFBP7) in 81 patients.Results: Patients with SLE were less educated with abnormal cognitive function compared with HCs. The levels of albumin, T3 (P < 0.05), and T4 decreased in low-cognition patients, while D-dimer, anti-dsDNA antibody, and IgM levels increased. The serum IgG and IgM levels showed a significant negative correlation with partial cognitive function. The serum T3 and T4 levels positively correlated with cognition. The expression of APOE, APOA1, IGF-1, and IGFBP7 showed no difference between the high- and low-cognition groups. However, the serum APOE level negatively correlated with Line Orientation, APOA1 positively correlated with Coding, and IGFBP7 negatively correlated with Graphic copy (P < 0.05), and IGF-1 had no correlation with any cognitive functions.Conclusions: Thyroid hormones (T3 and T4) and lipoproteins (APOE, APOA1, and IGFBP7) were associated with cognitive dysfunction in SLE. Whether T3 and T4 can be used in clinical practice as the biomarkers of cognitive dysfunction in SLE needs further exploration.