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Type 2 diabetes mellitus (T2DM) is associated with brain damage and cognitive decline. Despite the fact that the thalamus involves aspects of cognition and is typically affected in T2DM, existing knowledge of subregion-level thalamic damage and its associations with cognitive performance in T2DM patients is limited. The thalamus was subdivided into 8 subregions in each hemisphere. Resting-state functional and structural MRI data were collected to calculate resting-state functional connectivity (rsFC) and gray matter volume (GMV) of each thalamic subregion in 62 T2DM patients and 50 healthy controls. Compared with controls, T2DM patients showed increased rsFC of the medial pre-frontal thalamus, posterior parietal thalamus, and occipital thalamus with multiple cortical regions. Moreover, these thalamic functional hyperconnectivity were associated with better cognitive performance and lower glucose variability in T2DM patients. However, there were no group differences in GMV for any thalamic subregions. These findings suggest a possible neural compensation mechanism whereby selective thalamocortical functional hyperconnectivity facilitated by better glycemic control help to preserve cognitive ability in T2DM patients, which may ultimately inform intervention and prevention of T2DM-related cognitive decline in real-world clinical settings.

Background: It has been reported that type 2 diabetes (T2DM) is associated with olfactory identification (OI) impairments and cognitive decline. However, the relationship between OI impairments and cognitive decline is largely unknown in T2DM patients.Methods: Sixty-eight T2DM patients and 68 healthy controls underwent 3D-T1 MRI scans, olfactory and cognitive assessments. The cortical thickness of olfaction-related brain regions, olfactory and cognitive scores were compared between groups. Correlation analyses were carried out among cognition, olfaction, and cortical thickness of olfaction-related brain regions.Results: First, the cognitive and olfactory test scores of T2DM patients were lower than healthy subjects. Second, higher olfactory scores were associated with increased cortical thickness in the left parahippocampal gyrus and bilateral insula in T2DM. Third, higher olfactory scores were associated with higher cognitive performance in T2DM. Fourth, some cognitive performances were related to cortical thickness in the left parahippocampal gyrus and left insula in T2DM.Conclusion: These findings indicated that olfactory dysfunction may be useful for future applications that attempt to predict cognitive decline or develop tailored therapies in T2DM patients.

To explore the correlation between diabetic nephropathy (DN) and cognitive impairment through examining the cognitive function and the metabolism of the cerebrum in Type 2 diabetes mellitus patients at different stages of renal function. Eighty six patients with Type 2 diabetes mellitus (T2DM) were enrolled for this study. According to the urinary albumin excretion rate (UAER), the patients were divided into a T2DM without DN group (DM group, n=33), an early DN group (DN-III group, n=26) and a clinical stage group (DN-IV group, n=27). Thirty healthy adults were selected as a control group (NC group). Biochemical indexes and UAER were measured, and glomerular filtration rate (GFR) was detected by single-photon emission computed tomography (SPECT). The cognitive function was measured by Montreal Cognitive Assessment (MoCA, Beijing version) and mini-mental state examination (MMSE). The peak areas of N-acetylasparte (NAA), creatine (Cr), choline-containing compounds (Cho) were detected by proton magnetic resonance spectroscopy (1H-MRS). 1) There was no statistical difference in MMSE scores between the DM group and the control group. The scores of MoCA in the DN-III group or in the DN-IV group were significant less than that in the NC group (F=3.66, P0.05); 2) There was significant difference in left N-acetylaspartate (LNAA), left choline (LCho) among the diabetes groups. Compared with the DM group, the level of LNAA was decreased significantly (t=3.826, P0.05) while the LCho was increased significantly (t=4.373, P0.05) in the DN groups, with statistic difference between the 2 groups (t=3.693, P0.05); 3) The MoCA scores of T2DM patients were negatively correlated with UAER (r=-0.285, P0.05), while positively correlated with GFR (r=0.379, P0.05); 4) Logistic regression analysis indicated that UAER and GFR were the major risky factors for diabetic cognitive impairment. Diabetic cognitive impairment is closely correlated with the nephropathy in patients with Type 2 diabetes. With the decline in glomerular filtration function, the cognitive disorder tends to be aggravated. The hippocampal brain metabolism may have some changes in left side of Cho/Cr in patients with diabetic nephropathy.目的：通过检测不同时期的2型糖尿病肾病(diabetic nephropathy，DN)患者认知功能及脑代谢的变化，探讨2型糖尿病认知功能障碍与肾微血管病变的相关性。方法：86例2型糖尿病患者根据尿白蛋白排泄率(urinary albumin excretion rate，UAER)水平分为糖尿病无肾病组(DM组，n=33)、早期DN组(DN-III组，n=26)、临床期DN组(DN-IV组，n=27)，另选健康受试者为正常对照组(NC组，n=30)。所有受试者均检测血生物化学指标和UAER，使用单光子发射计算机断层成像术检测肾小球滤过率(glomerular filtration rate，GFR)。用简明精神状态量表(mini-mental state examination，MMSE)和蒙特利尔认知评估量表(Montreal Cognitive Assessment，MoCA)评估认知功能的变化。用氢磁共振质子波谱分析技术检测N-乙酰天冬氨酸(N-acetylasparte，NAA)峰、含胆碱复合物(choline-containing compounds，Cho)峰、肌酸复合物(creatine，Cr)峰的共振峰波谱峰值及波峰曲线下面积。结果：1)4组受试者MMSE评分差异均无统计学意义(均P0.05)。DN-III组及DN-IV组患者MoCA总分较对照组均显著降低(均P0.05)；2)DN组左侧NAA值较DM组显著下降(t=3.826，P0.05)，而左侧Cho水平明显增高(t=4.373，P0.05)；两组患者中左侧Cho/Cr差异有统计学意义(t=3.693，P0.05)；3)Pearson相关分析显示：2型糖尿病患者MoCA评分与UAER呈负相关(r=−0.285，P0.05)，与GFR呈正相关(r=0.379，P0.05)；4)Logistic回归分析显示UAER增高与GFR下降是糖尿病认知功能障碍的独立危险因素。结论：2型糖尿病患者认知功能障碍与肾微血管病变存在相关性，且随着肾损害程度的加重，认知功能障碍呈逐渐加重的趋势。DN患者海马存在代谢物质的改变，表现为左侧海马Cho/Cr增高。.