Objective: To study the relationship of Nε-(carboxymethyl)-lysine level (CML)
with microstructure changes of white matter (WM), and cognitive impairment
in patients with type 2 diabetes mellitus (T2DM) and to discuss the
potential mechanism underlying T2DM-associated cognitive impairment. Methods: The study was performed in T2DM patients (n=22) with disease course
≥5 years and age ranging from 65 to 75 years old. A control group consisted
of 25 sex- and age-matched healthy volunteers. Fractional anisotropy (FA) of
several WM regions was analyzed by diffusion tensor imaging scan. Plasma CML
levels were measured by enzyme-linked immunosorbent assay, and cognitive
function was assessed by Mini-Mental State Examination and Montreal
cognitive assessment (MoCA). Results: The total Mini-Mental State Examination score in the patient group
(25.72±3.13) was significantly lower than the control group (28.16±2.45)
(p<0.05). In addition, the total MoCA score in the patient group
(22.15±3.56) was significantly lower than the control group 25.63±4.12)
(p<0.01). In the patient group, FA values were significantly decreased in
the corpus callosum, cingulate fasciculus, inferior fronto-occipital
fasciculus, parietal WM, hippocampus, and temporal lobes relative to
corresponding regions of healthy controls (p<0.05). Plasma CML level was
negatively correlated with average FA values in the global brain (r=−0.58,
p<0.01) and MoCA scores (r=−0.47, p<0.05). Conclusions: In T2DM, WM microstructure changes occur in older patients, and
elevations in CML may play a role in the development of cognitive
impairment.