INTRODUCTION AND PURPOSE

Type 2 Diabetes Mellitus (T2DM) patients suffer from cognitive deficits of memory, executive function, attention, visuospatial capabilities, and other domains ¹. T2DM can be applied as an individual independent risk factor for Alzheimer’s disease (AD) ². T2DM patients may be at a higher risk of developing AD ³. The relationship between iron accumulation and cognitive decline in T2DM has not been fully revealed and publicized. This research focuses on assessing the global iron content and high iron content (RII) levels of the gray nucleus using quantitative susceptibility mapping (QSM), and to analyze the correlation between magnetic susceptibility value (MSV) with significant differences and clinical laboratory indicators and cognitive scores in T2DM Patients.

MATERIALS AND METHODS

34 cases of clinically confirmed T2DM and 14 age- and sex- matched healthy volunteers (HC) underwent conventional MR sequences and strategically acquired gradient echo (STAGE) scanning on a Philips Ingenia CX 3.0 T MR scanner. The magnetic susceptibility values of whole-structural (MSV_wh) and regional high iron (MSV_hi) areas on bilateral head of caudate nucleus (HCN), globus pallidus (GP), putamen (PUT), pulvinar thalamus (PT), subthalamic nucleus (STN), red nucleus (RN), substantia nigra (SN), dentate nucleus (DN) and gyri fasciolaris (GF) were measured in post processing QSM image using signal processing in nuclear magnetic resonance (SPIN) software in T2DM patients and HC’s. The MSV_wh mean reduce 2SD of MSV in each nucleus of the HC group was used as the threshold to determine the MSV_hi of patients. Clinical data, laboratory examination indexes and Mini-mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), California verbal learning test (CVLT), Symbol Digit modalities test (SDMT) were collected.
Data analyses were performed using statistical package for social science (SPSS) version 25.0. ICC test was calculated to evaluate inter-observer reliability. Independent samples t-test (for normally distributed data) or Mann–Whitney U test (for non-normally distributed data) or chi-square test (Enumeration data) was used to compare the MSV of gray nucleus, clinical data, laboratory examination indexes and Cognitive scores between T2DM group and HC group. Pearson correlation analysis (for normally distributed data) or Spearman correlation analysis (for non-normally distributed data) was used to analyze the correlation between MSV with significant differences and clinical laboratory indicators and cognitive scores. P < 0.05 was considered statistically significant.

RESULTS

Significant differences were found in glycated hemoglobin (HbA1c), fasting plasma glucose (FG), SDMT between T2DM group and HC group (P < 0.05).
Compared with HC group, the MSV_wh values of all gray nucleus in T2DM group were increased by 9.8-25.7%, and there were significant differences in right HCN, right PUT, bilateral GP, right STN and left GF (P < 0.05, Fig.1-A). The correlation between the MSV_wh of gray nucleus with significant differences and clinical laboratory indicators and cognitive scores in T2DM group is shown in Fig.2, where MSV_wh in the right PUT is most relevant to MoCA (r = -0.482, P = 0.004) (Fig.4).
Compared with HC group, the MSV_hi values of all gray nucleus in T2DM group were increased by 9.2-21.8%, and there were significant differences in right HCN, right PUT, bilateral GP and left GF (P < 0.05 Fig.1-B). The correlation between the MSV_hi of gray nucleus with significant differences and clinical laboratory indicators and cognitive scores in T2DM group is shown in Fig.3, where MSV_hi in the right PUT is most correlated with MoCA (r = -0.485, P = 0.004) (Fig.5).

DISCUSSION AND CONCLUSION

Increased iron deposition in the gray nucleus in T2DM patients were associated with cognitive deficits. Further evaluations are needed to research iron burden and their diagnostic role in dementia pathology of T2DM in the future.

Acknowledgements

No acknowledgement found.

References

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3. Redondo MT, Beltran-Brotons JL, Reales JM, Ballesteros S. Executive functions in patients with Alzheimer's disease, type 2 diabetes mellitus patients and cognitively healthy older adults. Exp Gerontol 2016;83:47-55.