Ventral striatum, but not cortical volume loss, is related to cognitive dysfunction in type 1 diabetic patients with and without microangiopathy

Cerebral Small Vessel Disease Is Associated With Smaller Brain Volumes in Adults With Type 1 Diabetes

Introduction: Type 1 diabetes has been linked to brain volume reductions as well as to cerebral small vessel disease (cSVD). This study concerns the relationship between normalized brain volumes (volume fractions) and cSVD, which has not been examined previously. Methods: We subjected brain magnetic resonance imaging studies of 187 adults of both sexes with Type 1 diabetes and 30 matched controls to volumetry and neuroradiological interpretation. Results: Participants with Type 1 diabetes had smaller thalami compared to controls without diabetes (p = 0.034). In subgroup analysis of the Type 1 diabetes group, having any sign of cSVD was associated with smaller cortical (p = 0.031) and deep gray matter volume fractions (p = 0.029), but a larger white matter volume fraction (p = 0.048). After correcting for age, the smaller putamen volume remained significant. Conclusions: We found smaller thalamus volume fractions in individuals with Type 1 diabetes as compared to those without diabetes, as well as reductions in brain volume fractions related to signs of cSVD in individuals with Type 1 diabetes.

Type 2 Diabetes and Biomarkers of Brain Structure, Perfusion, Metabolism, and Function in Late Mid-Life: A Multimodal Discordant Twin Study

BACKGROUND

Type 2 diabetes (T2D) is associated with an increased risk of dementia and early features may become evident even in mid-life. Characterizing these early features comprehensively requires multiple measurement modalities and careful selection of participants with and without T2D.

OBJECTIVE

We conducted a cross-sectional multimodal imaging study of T2D-discordant twins in late mid-life to provide insights into underlying mechanisms.

METHODS

Measurements included computerized cognitive battery, brain MRI (including arterial spin labelling, diffusion tensor, resting state functional), fluorodeoxyglucose (FDG)-PET, and retinal optical coherence tomography.

RESULTS

There were 23 pairs, mean age 63.7 (±6.1) years. In global analyses, T2D was associated with poorer attention (β= -0.45, p <0.001) and with reduced FDG uptake (β= -5.04, p = 0.02), but not with cortical thickness (p = 0.71), total brain volume (p = 0.51), fractional anisotropy (p = 0.15), mean diffusivity (p = 0.34), or resting state activity (p = 0.4). Higher FDG uptake was associated with better attention (β= 3.19, p = 0.01) but not with other cognitive domains. In regional analyses, T2D was associated with lower accumbens volume (β= -44, p = 0.0004) which was in turn associated with poorer attention.

CONCLUSION

T2D-related brain dysfunction in mid-life manifests as attentional loss accompanied by evidence of subtle neurodegeneration and global reduction in cerebral metabolism, in the absence of overt cerebrovascular disease.

Central nervous system microstructural alterations in Type 1 diabetes mellitus: A systematic review of diffusion Tensor imaging studies

AIMS

Type 1 diabetes mellitus (T1DM) is a chronic childhood disease with potentially persistent CNS disruptions. In this study, we aimed to systematically review diffusion tensor imaging studies in patients with T1DM to understand the microstructural effects of this entity on individuals' brains METHODS: We performed a systematic search and reviewed the studies to include the DTI studies in individuals with T1DM. The data for the relevant studies were extracted and a qualitative synthesis was performed.

RESULTS

A total of 19 studies were included, most of which showed reduced FA widespread in optic radiation, corona radiate, and corpus callosum, as well as other frontal, parietal, and temporal regions in the adult population, while most of the studies in the juvenile patients showed non-significant differences or a non-persistent pattern of changes. Also, reduced AD and MD in individuals with T1DM compared to controls and non-significant differences in RD were noted in the majority of studies. Microstructural alterations were associated with clinical profile, including age, hyperglycemia, diabetic ketoacidosis and cognitive performance.

CONCLUSION

T1DM is associated with microstructural brain alterations including reduced FA, MD, and AD in widespread brain regions, especially in association with glycemic fluctuations and in adult age.

Alterations in Functional Connectivity of Thalamus and Primary Somatosensory Cortex in Painful and Painless Diabetic Peripheral Neuropathy

OBJECTIVE

In this study we aimed to investigate the functional connectivity of brain regions involved in sensory processing in diabetes with and without painful and painless diabetic peripheral neuropathy (DPN) and the association with peripheral nerve function and pain intensity.

RESEARCH DESIGN AND METHODS

In this cross-sectional study we used resting-state functional MRI (fMRI) to investigate functional brain connectivity of 19 individuals with type 1 diabetes and painful DPN, 19 with type 1 diabetes and painless DPN, 18 with type 1 diabetes without DPN, and 20 healthy control subjects. Seed-based connectivity analyses were performed for thalamus, postcentral gyrus, and insula, and the connectivity z scores were correlated with peripheral nerve function measurements and pain scores.

RESULTS

Overall, compared with those with painful DPN and healthy control subjects, subjects with type 1 diabetes without DPN showed hyperconnectivity between thalamus and motor areas and between postcentral gyrus and motor areas (all P ≤ 0.029). Poorer peripheral nerve functions and higher pain scores were associated with lower connectivity of the thalamus and postcentral gyrus (all P ≤ 0.043). No connectivity differences were found in insula (all P ≥ 0.071).

CONCLUSIONS

Higher functional connectivity of thalamus and postcentral gyrus appeared only in diabetes without neuropathic complications. Thalamic/postcentral gyral connectivity measures demonstrated an association with peripheral nerve functions. Based on thalamic connectivity, it was possible to group the phenotypes of type 1 diabetes with painful/painless DPN and type 1 diabetes without DPN. The results of the current study support that fMRI can be used for phenotyping, and with validation, it may contribute to early detection and prevention of neuropathic complications.

Gray Matter Brain Alterations in Type 1 Diabetes - Findings Based on Detailed Phenotyping of Neuropathy Status

AIMS

This study investigated brain structure in patients of type 1 diabetes with diabetic peripheral neuropathy (DPN) and type 1 diabetes with neuropathic pain and the associations to clinical, peripheral, and cognitive measurements.

METHODS

Sixty individuals with type 1 diabetes and 20 healthy controls were included in the study. Nineteen individuals with type 1 diabetes and neuropathic pain, 19 with type 1 diabetes and DPN, 18 with type 1 diabetes without DPN, and 20 healthy controls were included in the brain analyses. We utilized structural brain magnetic resonance imaging to investigate total and regional gray matter volume.

RESULTS

Significant lower gray matter volume was found in type 1 diabetes with neuropathic pain and in type 1 diabetes without DPN compared to healthy controls (p=0.024 and p=0.019, respectively). Lower insula volume was observed in all three diabetes groups (all p≤0.050). Thalamus and hippocampus volume was lower in type 1 diabetes with neuropathic pain, cerebellum volume was lower in type 1 diabetes with DPN, and somatosensory cortex volume was lower in type 1 diabetes without DPN (all p≤0.018). Attenuated memory was associated with lower gray matter volume in type 1 diabetes with DPN. No associations were found between gray matter volume and clinical/peripheral measurements.

CONCLUSION

We demonstrated lower gray matter volume in individuals with type 1 diabetes regardless of the presence of DPN and neuropathic pain. Hence, central gray matter alteration was not associated with peripheral alterations.

Region-specific changes in aquaporin 4 induced by hyperglycemia underlie the differences in cell swelling in the cortex and striatum after cerebral ischemia-reperfusion

Brain edema is a major cause of death in patients who suffer an ischemic stroke. Diabetes has been shown to aggravate brain edema after cerebral ischemia-reperfusion, but few studies have focused on the heterogeneity of this response across different brain regions. Aquaporin 4 plays an important role in the formation and regression of brain edema. Here, we report that hyperglycemia mainly affects the continuity of aquaporin 4 distribution around blood vessels in the cortical penumbra after ischemia-reperfusion; however, in the striatal penumbra, in addition to affecting the continuity of distribution, it also substantially affects the fluorescence intensity and the polarity distribution in astrocytes. Accordingly, hyperglycemia induces a more significant increase in the number of swelling cells in the striatal penumbra than in the cortical penumbra. These results can improve our understanding of the mechanism underlying the effects of diabetes in cerebral ischemic injury and provide a theoretical foundation for identification of appropriate therapeutic modalities.

Early prediction of putamen imaging features in HIV-associated neurocognitive impairment syndrome

Background

To explore the correlation between the volume of putamen and brain cognitive impairment in patients with HIV and to predict the feasibility of early-stage HIV brain cognitive impairment through radiomics.

Method

Retrospective selection of 90 patients with HIV infection, including 36 asymptomatic neurocognitive impairment (ANI) patients and 54 pre-clinical ANI patients in Beijing YouAn Hospital. All patients received comprehensive neuropsychological assessment and MRI scanning. 3D Slicer software was used to acquire volume of interest (VOI) and radiomics features. Clinical variables and volume of putamen were compared between patients with ANI and pre-clinical ANI. The Kruskal Wallis test was used to analysis multiple comparisons between groups. The relationship between cognitive scores and VOI was compared using linear regression. For radiomics, principal component analysis (PCA) was used to reduce model overfitting and calculations and then a support vector machine (SVM) was used to build a binary classification model. For model performance evaluation, we used an accuracy, sensitivity, specificity and receiver operating characteristic curve (ROC).

Result

There were no significant differences in clinical variables between ANI group and pre-clinical-ANI group (P>0.05). The volume of bilateral putamen was significantly different between AHI group and pre-clinical group (P<0.05), but there was only a trend in the left putamen between ANI-treatment group and pre-clinical treatment group(P = 0.063). Reduced cognitive scores in Verbal Fluency, Attention/Working Memory, Executive Functioning, memory and Speed of Information Processing were negatively correlated with the increased VOI (P<0.05), but the correlation was relatively low. In diagnosing the ANI from pre-clinical ANI, the mean area under the ROC curves (AUC) were 0.85 ± 0.22, the mean sensitivity and specificity were 63.12 ± 5.51 and 94.25% ± 3.08%.

Conclusion

The volumes of putamen in patients with ANI may be larger than patients with pre-clinical ANI, the change of the volume of the putamen may have a certain process; there is a relationship between putamen and cognitive impairment, but the exact mechanism is unclear. Radiomics may be a useful tool for predicting early stage HAND in patients with HIV.

Type 2 Diabetes Mellitus May Exacerbate Gray Matter Atrophy in Patients With Early-Onset Mild Cognitive Impairment

Background

The precise physiopathological association between the courses of neurodegeneration and cognitive decline in type 2 diabetes mellitus (T2DM) remains unclear. This study sought to comprehensively investigate the distribution characteristics of gray matter atrophy in middle-aged T2DM patients with newly diagnosed mild cognitive impairment (MCI).

Methods

Four groups, including 28 patients with early-onset MCI, 28 patients with T2DM, 28 T2DM patients with early-onset MCI (T2DM-MCI), and 28 age-, sex-, and education-matched healthy controls underwent three-dimensional high-resolution structural magnetic resonance imaging. Cortical and subcortical gray matter volumes were calculated, and a structural covariance method was used to evaluate the morphological relationships within the default mode network (DMN).

Results

Overlapped and unique cortical/subcortical gray matter atrophy was found in patients with MCI, T2DM and T2DM-MCI in our study, and patients with T2DM-MCI showed lower volumes in several areas than patients with MCI or T2DM. Volume loss in subcortical areas (including the thalamus, putamen, and hippocampus), but not in cortical areas, was related to cognitive impairment in patients with MCI and T2DM-MCI. No associations between biochemical measurements and volumetric reductions were found. Furthermore, patients with MCI and those with T2DM-MCI showed disrupted structural connectivity within the DMN.

Conclusion

These findings provide further evidence that T2DM may exacerbate atrophy of specific gray matter regions, which may be primarily associated with MCI. Impairments in gray matter volume related to T2DM or MCI are independent of cardiovascular risk factors, and subcortical atrophy may play a more pivotal role in cognitive impairment than cortical alterations in patients with MCI and T2DM-MCI. The enhanced structural connectivity within the DMN in patients with T2DM-MCI may suggest a compensatory mechanism for the chronic neurodegeneration.

Genomic ancestry and glycemic control in adolescents with type 1 diabetes: A multicenter study in Brazil

OBJECTIVE

To determine the influence of genomic ancestry (GA) and self-reportedcolor-race (SRCR) on glycemic control in adolescents with type 1 diabetes (T1D) in an admixed population.

RESEARCH DESIGN AND METHODS

This multicenter nationwide study was conducted in 14 public clinics in 10 Brazilian cities. We estimated global and individual African, European, and Native Amerindian GA proportions using a panel of 46 AIM-INDEL markers. From 1760 patients, 367 were adolescents (20.9%): 184 female (50.1%), aged 16.4 ± 1.9 years, age at diagnosis 8.9 ± 4.3 years, duration of diabetes 8.1 ± 4.3 years, years of study 10.9 ± 2.5 and HbA1c of 9.6 ± 2.4%.

RESULTS

Patients SRCR as White: 176 (48.0%), Brown: 159 (43.3%), Black: 19(5.2%), Asians: 5 (1.4%) and Amerindians: 8 (2.2%). The percentage of European GA prevailed in all groups: White (71.1), Brown (58.8), Black (49.6), Amerindians (46.1), and Asians (60.5). Univariate correlation was noted between A1c and African GA, r = 0.11, P = .03; years of study, r = -0.12 P = .010, and having both private and public health care insurance (r = -0.20, P < .001). After adjustments, the multivariate logistic analysis showed that SRCR or GA did not influence glycemic control.

CONCLUSIONS

A high percentage of European GA was noted in our patients, even in those who self-reported as non-White, confirming the highly admixed ethnicity of the Brazilian population. Better glycemic control was associated with having both types of health care; however, there was no association between glycemic control with GA or SRCR. Future prospective studies with other admixed populations are necessary to confirm our findings.

Health literacy and glycemic control in patients with diabetes: a tertiary care center study in Brazil

BACKGROUND

The primary objective of our study was to determine which factors influence health literacy (HL) in patients with type 1 diabetes (T1D) and type 2 diabetes (T2D), and the secondary one was to evaluate the influence of HL on glycemic control.

METHODS

This was an observational, cross-sectional study with 347 patients (144 with T1D and 203 with T2D), conducted between December 2014/December 2017. Data were obtained from medical records and/or questionnaire. The short test of Functional Health Literacy (S-TOFHLA) was used to evaluate HL.

RESULTS

Age and years of school attendance were the most important variables associated with better performance in S-TOFHLA mainly in patients with T1D. A correlation between age and years of school attendance with S-TOFHLA score was observed in both groups of patients. After an unadjusted analysis, more patients with T1D presented adequate HL [119 (82.6%) vs 87 (44.8%, p < 0.001)]. Patients with T1D had higher scores than patients with T2D (84.4 ± 21.4 vs 61.6 ± 26.8 points, p < 0.001), respectively. This difference did not persist after adjustment for age and years of school attendance (73.04 ± 2.14 ± vs 70.04 ± 1.76 points) respectively, p = 0.348). No difference was found in HbA1c levels according to S-TOFHLA. All patients with T1D and HbA1c levels < 7.0% (53 mmol/mol) had adequate HL.

CONCLUSIONS

A considerable number of patients with either T1D or T2D did not have adequate HL. Overall, age and years of school attendance were the most important variables associated with better performance of S-TOFHLA. Although no difference was found in HbA1c levels according to S-TOFHLA, patients with T1D who self-reported as White, with more years of school attendance, and higher HL score reached more frequently a good glycemic control. Finally, in addition to therapeutic regimens, approaches on diabetes management should also include patients' HL evaluation along with psychological and social aspects.

Bis(ethylmaltolato)oxidovanadium(iv) inhibited the pathogenesis of Alzheimer's disease in triple transgenic model mice

Vanadium compounds have been reported to mimic the anti-diabetes effects of insulin on rodent models, but their effects on Alzheimer's disease (AD) have rarely been explored. In this paper, 9-month-old triple transgenic AD model mice (3×Tg-AD) received bis(ethylmaltolato)oxidovanadium(iv) (BEOV) at doses of 0.2 mmol L^-1 (68.4 μg mL^-1) and 1.0 mmol L^-1 (342 μg mL^-1) for 3 months. BEOV at both doses was found to improve contextual memory and spatial learning in AD mice. It also improved glucose metabolism and protected neuronal synapses in the AD brain, as evidenced respectively by ¹⁸F-labeled fluoro-deoxyglucose positron emission tomography (¹⁸F-FDG-PET) scanning and by transmission electron microscopy. Inhibitory effects of BEOV on β-amyloid (Aβ) plaques and neuronal impairment in the cortex and hippocampus of fluorescent AD mice were visualized three-dimensionally by applying optical clearing technology to brain slices before confocal laser scanning microscopy. Western blot analysis semi-quantitatively revealed the altered levels of Aβ₄₂ in the brains of wildtype, AD, and AD treated with 0.2 and 1.0 mmol L^-1 BEOV mice (70.3%, 100%, 83.2% and 56.8% in the hippocampus; 82.4%, 100%, 66.9% and 42% in the cortex, respectively). The mechanism study showed that BEOV increased the expression of peroxisome proliferator-activated receptor γ (PPARγ) (140%, 100%, 142% and 160% in the hippocampus; 167%, 100%, 124% and 133% in the cortex) to inactivate the JAK2/STAT3/SOCS-1 pathway and to block the amyloidogenesis cascade, thus attenuating Aβ-induced insulin resistance in AD models. BEOV also reduced protein tyrosine phosphatase 1B (PTP1B) expression (74.8%, 100%, 76.5% and 53.8% in the hippocampus; 71.8%, 100%, 94.2% and 81.8% in cortex) to promote insulin sensitivity and to stimulate the PI3K/Akt/GSK3β pathway, subsequently reducing tau hyperphosphorylation (phosphorylated tau396 levels were 51.1%, 100%, 56.1% and 50.2% in the hippocampus; 22.2%, 100%, 36.1%, and 24% in the cortex). Our results suggested that BEOV reduced the pathological hallmarks of AD by targeting the pathways of PPARγ and PTP1B in 3×Tg AD mice.

Large-Scale Neuronal Network Dysfunction in Diabetic Retinopathy

Diabetic retinopathy (DR) patients are at an increased risk of cognitive decline and dementia. There is accumulating evidence that specific functional and structural architecture changes in the brain are related to cognitive impairment in DR patients. However, little is known regarding whether the functional architecture of resting-state networks (RSNs) changes in DR patients. The purpose of this study was to investigate the intranetwork functional connectivity (FC) and functional network connectivity (FNC) of RSN changes in DR patients using independent component analysis (ICA). Thirty-four DR patients (18 men and 16 women; mean age, 53.53 ± 8.67 years) and 38 nondiabetic healthy controls (HCs) (15 men and 23 women; mean age, 48.63 ± 11.83 years), closely matched for age, sex, and education, underwent resting-state magnetic resonance imaging scans. ICA was applied to extract the nine RSNs. Then, two-sample t-tests were conducted to investigate different intranetwork FCs within nine RSNs between the two groups. The FNC toolbox was used to assess interactions among RSNs. Pearson correlation analysis was conducted to explore the relationship between intranetwork FCs and clinical variables in the DR group. A receiver operating characteristic (ROC) curve was conducted to assess the ability of the intranetwork FCs of RSNs in discriminating between the two groups. Compared to the HC group, DR patients showed significant decreased intranetwork FCs within the basal ganglia network (BGN), visual network (VN), ventral default mode network (vDMN), right executive control network (rECN), salience network (SN), left executive control network (lECN), auditory network (AN), and dorsal default mode network (dDMN). In addition, FNC analysis showed increased VN-BGN, VN-vDMN, VN-dDMN, vDMN-lECN, SN-BGN, lECN-dDMN, and AN-BGN FNCs in the DR group, relative to the HC group. Furthermore, altered intranetwork FCs of RSNs were significantly correlated with the glycosylated hemoglobin (HbA1c) level in DR patients. A ROC curve showed that these specific intranetwork FCs of RSNs discriminated between the two groups with a high degree of sensitivity and specificity. Our study highlighted that DR patients had widespread deficits in both low-level perceptual and higher-order cognitive networks. Our results offer important insights into the neural mechanisms of visual loss and cognitive decline in DR patients.

Brain and Body: A Review of Central Nervous System Contributions to Movement Impairments in Diabetes

Diabetes is associated with a loss of somatosensory and motor function, leading to impairments in gait, balance, and manual dexterity. Data-driven neuroimaging studies frequently report a negative impact of diabetes on sensorimotor regions in the brain; however, relationships with sensorimotor behavior are rarely considered. The goal of this review is to consider existing diabetes neuroimaging evidence through the lens of sensorimotor neuroscience. We review evidence for diabetes-related disruptions to three critical circuits for movement control: the cerebral cortex, the cerebellum, and the basal ganglia. In addition, we discuss how central nervous system (CNS) degeneration might interact with the loss of sensory feedback from the limbs due to peripheral neuropathy to result in motor impairments in individuals with diabetes. We argue that our understanding of movement impairments in individuals with diabetes is incomplete without the consideration of disease complications in both the central and peripheral nervous systems. Neuroimaging evidence for disrupted central sensorimotor circuitry suggests that there may be unrecognized behavioral impairments in individuals with diabetes. Applying knowledge from the existing literature on CNS contributions to motor control and motor learning in healthy individuals provides a framework for hypothesis generation for future research on this topic.

Cognitive Dysfunction in Type 1 Diabetes Mellitus

CONTEXT

We have summarized key studies assessing the epidemiology, mechanisms, and consequences of cognitive dysfunction (CD) in type 1 diabetes.

EVIDENCE SYNTHESIS

In a number of studies, the severity of CD in type 1 diabetes was affected by the age of onset and duration, and the presence of proliferative retinopathy and autonomic neuropathy. Diabetes-related CD has been observed, not only in adults, but also in children and adolescents. Most neuroimaging studies of patients with type 1 diabetes did not show any differences in whole brain volumes; however, they did reveal selective deficits in gray matter volume or density within the frontal, posterior, and temporal cortex and subcortical gray matter. Studies of middle-age adults with long-standing type 1 diabetes using diffusion tensor imaging have demonstrated partial lesions in the white matter and decreased fractional anisotropy in posterior brain regions. The mechanisms underlying diabetes-related CD are very complex and include factors related to diabetes per se and to diabetes-related cardiovascular disease and microvascular dysfunction, including chronic hyperglycemia, hypoglycemia, macro- and microvascular disease, and increased inflammatory cytokine expression. These mechanisms might contribute to the development and progression of both vascular dementia and Alzheimer disease.

CONCLUSIONS

Higher rates of CD and faster progression in type 1 diabetes can be explained by both the direct effects of altered glucose metabolism on the brain and diabetes-related cardiovascular disease. Because the presence and progression of CD significantly worsens the quality of life of patients with diabetes, further multidisciplinary studies incorporating the recent progress in both neuroimaging and type 1 diabetes management are warranted to investigate this problem.

Sweet Mitochondria: A Shortcut to Alzheimer's Disease

A growing body of evidence supports a clear association between Alzheimer's disease and diabetes and several mechanistic links have been revealed. This paper is mainly devoted to the discussion of the role of diabetes-associated mitochondrial defects in the pathogenesis of Alzheimer's disease. The research experience and views of the author on this subject will be highlighted.

Early intervention with gastrodin reduces striatal neurotoxicity in adult rats with experimentally‑induced diabetes mellitus

Glutamate-induced excitotoxicity in the striatum has an important role in neurodegenerative diseases. It has been reported that diabetes mellitus (DM) induces excitotoxicity in striatal neurons, although the underlying mechanism remains to be fully elucidated. The present study aimed to investigate the effect of gastrodin on DM-induced excitotoxicity in the striatal neurons of diabetic rats. Adult Sprague-Dawley rats were divided into control, diabetic, and gastrodin intervention groups. Diabetes in the rats was induced with a single intraperitoneal injection of streptozotocin (65 mg/kg). In the gastrodin groups, the rats were gavaged with 60 or 120 mg/kg/day gastrodin for 6 weeks, 3 weeks following the induction of diabetes. Pathological alterations in the striatum were assessed using hematoxylin and eosin (H&E) staining. The protein expression levels of phosphorylated (p)-extracellular signal-regulated kinase (ERK)1/2, p-mitogen-activated protein kinase kinase (MEK)1/2, tyrosine receptor kinase B (TrKB) and brain-derived neurotrophic factor (BDNF) in the striatal neurons were evaluated by western blotting and double immunofluorescence. Additionally, the extracellular levels of glutamate were measured by microanalysis followed by high-pressure-liquid-chromatography. In diabetic rats, striatal neuronal degeneration was evident following H&E staining, which revealed the common occurrence of pyknotic nuclei. This was coupled with an increase in glutamate levels in the striatal tissues. The protein expression levels of p-ERK1/2, p-MEK1/2, TrKB and BDNF in the striatal tissues were significantly increased in the diabetic rats compared with those in the normal rats. In the gastrodin groups, degeneration of the striatal neurons was ameliorated. Furthermore, the expression levels of glutamate, p-ERK1/2, p-MEK1/2, TrKB and BDNF in the striatal neurons were decreased. From these findings, it was concluded that reduced neurotoxicity in striatal neurons following treatment with gastrodin may be attributed to its suppressive effects on the expression of p-ERK1/2, p-MEK1/2, BDNF and TrKB.

Accelerated executive functions decline and gray matter structural changes in middle-aged type 1 diabetes mellitus patients with proliferative retinopathy

BACKGROUND

The aim of the present study was to determine trajectories of cognitive and cortical changes over time in middle-aged patients with type 1 diabetes mellitus (T1DM) and proliferative retinopathy.

METHODS

Twenty-five patients and 25 controls underwent neuropsychological assessment and neuroimaging twice in a mean (±SD) of 3.56 ± 0.65 and 3.94 ± 0.91 years, respectively (P = 0.098). Cognitive assessment included the domains of general cognitive ability, memory, information processing speed, executive functions, attention, and motor and psychomotor speed. Symmetrized percentage change in local cortical thickness, surface area, and volume was determined using the FreeSurfer 6 vertex-wise general linear model method. Analyses were performed uncorrected and corrected for baseline systolic blood pressure and depressive symptoms.

RESULTS

In patients versus controls, accelerated executive function decline was accompanied by, but not related to, lower left frontal and temporal surface area, left parietal and right frontal thickness, and bilateral frontal and right posterior cingulate volume (family-wise error [FWE]-corrected P < 0.05 for all). In patients, lower executive performance was related to loss of right precuneus surface area (P_FWE  = 0.005). Higher HbA1c during follow-up was related to executive function decline (r = -0.509, P = 0.016) and loss of left hemisphere surface area (r_{corrected analysis}  = -0.555, P = 0.007).

CONCLUSIONS

After 3.5 years of follow-up, middle-aged T1DM patients with proliferative retinopathy, mild focal changes in executive functions, and cortical structure were found, which may indicate accelerated aging.

Effects of hypoglycaemia on working memory and regional cerebral blood flow in type 1 diabetes: a randomised, crossover trial

AIMS/HYPOTHESIS

The aim of this randomised, crossover trial was to compare cognitive functioning and associated brain activation patterns during hypoglycaemia (plasma glucose [PG] just below 3.1 mmol/l) and euglycaemia in individuals with type 1 diabetes mellitus.

METHODS

In this patient-blinded, crossover study, 26 participants with type 1 diabetes mellitus attended two randomised experimental visits: one hypoglycaemic clamp (PG 2.8 ± 0.2 mmol/l, approximate duration 55 min) and one euglycaemic clamp (PG 5.5 mmol/l ± 10%). PG levels were maintained by hyperinsulinaemic glucose clamping. Cognitive functioning was assessed during hypoglycaemia and euglycaemia conditions using a modified version of the digit symbol substitution test (mDSST) and control DSST (cDSST). Simultaneously, regional cerebral blood flow (rCBF) was measured in pre-specified brain regions by six H₂¹⁵O-positron emission tomographies (PET) per session.

RESULTS

Working memory was impaired during hypoglycaemia as indicated by a statistically significantly lower mDSST score (estimated treatment difference [ETD] -0.63 [95% CI -1.13, -0.14], p = 0.014) and a statistically significantly longer response time (ETD 2.86 s [7%] [95% CI 0.67, 5.05], p = 0.013) compared with euglycaemia. During hypoglycaemia, mDSST task performance was associated with increased activity in the frontal lobe regions, superior parietal lobe and thalamus, and decreased activity in the temporal lobe regions (p < 0.05). Working memory activation (mDSST - cDSST) statistically significantly increased blood flow in the striatum during hypoglycaemia (ETD 0.0374% [95% CI 0.0157, 0.0590], p = 0.002).

CONCLUSIONS/INTERPRETATION

During hypoglycaemia (mean PG 2.9 mmol/l), working memory performance was impaired. Altered performance was associated with significantly increased blood flow in the striatum, a part of the basal ganglia implicated in regulating motor functions, memory, language and emotion.

TRIAL REGISTRATION

NCT01789593, clinicaltrials.gov FUNDING: This study was funded by Novo Nordisk.

Does knowledge on diabetes management influence glycemic control? A nationwide study in patients with type 1 diabetes in Brazil

OBJECTIVE

The purpose of this study is to establish demographic and clinical data associated with the knowledge on diabetes management and its influence on glycemic control in patients with type 1 diabetes.

METHODS

This was a retrospective, observational, multicenter study conducted with 1,760 patients between August 2011 and August 2014 in 10 cities of Brazil.

RESULTS

Overall, 1,190 (67.6%) patients knew what glycated hemoglobin (HbA1c) means. These patients were older, had longer disease duration, longer follow-up in each center, reported lower frequency of self-reported hypoglycemia, and were more frequently Caucasians and at glycemic goal. Multivariate analysis showed that knowledge on what HbA1c means was related to more years of school attendance, self-reported ethnicity (Caucasians), severe hypoglycemia, economic status, follow-up time in each center, and participation on diabetes educational programs. Good glycemic control was related to older age, more years of school attendance, higher frequency of daily self-monitoring of blood glucose, higher adherence to diet, and knowledge on what HbA1c means.

CONCLUSION

Patients with a knowledge on what HbA1c means had a better chance of reaching an adequate glycemic control that was not found in the majority of our patients. Diabetes care teams should rethink the approaches to patients and change them to more proactive schedules, reinforcing education, patients' skills, and empowerment to have positive attitudes toward reaching and maintaining a better glycemic control. Finally, the glucocentric approach to diabetes management should be changed to actions that include patients' psychosocial aspects aiming to reduce the stress of living with diabetes, improving glycemic control, and avoiding adverse outcomes.

The impact of ethnicity, educational and economic status on the prescription of insulin therapeutic regimens and on glycemic control in patients with type 1 diabetes. A nationwide study in Brazil

AIMS

Establish the relationship between demographic, educational and economic status on insulin therapeutic regimens (ITRs) and on glycemic control in patients with type 1 diabetes.

METHODS

This was a cross-sectional, multicenter study with 1760 patients conducted between August 2011 and August 2014 in 10 Brazilian cities.

RESULTS

Patients were stratified according to ITRs as follows: only NPH insulin (group 1, n=80(4.5%)); only long-acting insulin analogs (group 2, n=6(0.3%)); continuous subcutaneous insulin infusion (CSII) (group 3, n=62(3.5%)); NPH plus regular insulin (group 4, n=710(40.3%)); NPH plus ultra-rapid insulin analogs (group 5, n=259(14.8%)); long-acting insulin analogs plus regular insulin (group 6, n=25(4.4%)) and long-acting plus ultra-rapid insulin analogs (group 7, n=618 (35.1%)). As group A (provided free of charge by the government) we considered groups 1 and 4, and as group B (obtained through lawsuit or out-of-pocket) groups 2, 3 and 7. Multivariate logistic analysis showed that independent variables related to group B were older age, more years of school attendance, higher economic status and ethnicity (Caucasians). The independent variables related to better glycemic control were older age, higher adherence to diet, higher frequency of self-monitoring of blood glucose, more years of school attendance and belonging to group B.

CONCLUSIONS

In Brazilian National Health Care System, prescriptions of insulin analogs or CSII are more frequent in Caucasian patients with type 1 diabetes, with higher economic status and more years ofschool attendance. Among these variables years of school attendance was the only one associated with better glycemic control.

Early ciliary and prominin-1 dysfunctions precede neurogenesis impairment in a mouse model of type 2 diabetes

Diabetes mellitus (DM) is reaching epidemic conditions worldwide and increases the risk for cognition impairment and dementia. Here, we postulated that progenitors in adult neurogenic niches might be particularly vulnerable. Therefore, we evaluated the different components of the mouse subventricular zone (SVZ) during the first week after chemical induction of type 1 and type 2 diabetes-like (T1DM and T2DM) conditions. Surprisingly, only T2DM mice showed SVZ damage. The initial lesions were localized to ependymal cilia, which appeared disorientated and clumped together. In addition, they showed delocalization of the ciliary membrane protein prominin-1. Impairment of neuroprogenitor proliferation, neurogenic marker abnormalities and ectopic migration of neuroblasts were found at a later stage. To our knowledge, our data describe for the first time such an early impact of T2DM on the SVZ. This is consistent with clinical data indicating that brain damage in T2DM patients differs from that in T1DM patients.

Diabetic retinopathy is a neurodegenerative disorder

Since 1875, controversy has ensued over whether ocular diabetic complications are primarily vasculopathic or neuropathic in nature. Here, we discuss the historical context by which diabetic retinopathy (DR) came to be considered a primary vasculopathy, in contrast to more recent data suggesting the importance of diabetic retinal neurodegeneration (DRN) as the primary manifestation of ocular diabetic damage. Unsurprisingly, DRN parallels other diabetic complications related to neuropathy. In general, there are three possible relationships between microvascular DR and DRN: i) microvasculopathy causes neurodegeneration; ii) neurodegeneration causes microvasculopathy or iii) they are mutually independent. The authors' group has recently produced experimental data showing that DRN precedes even the earliest manifestations of DR microvasculopathy. In combination with earlier studies showing that focal implicit time delays predicted future development of DR microvasculopathy in the same location, relationships i) and iii) are unlikely. As such, ii) is the most likely relationship: DRN is a cause of DR. Granted, additional studies are needed to confirm this hypothesis and elucidate the mechanism of diabetes-induced neurodegeneration. We conclude this review by proposing experimental approaches to test the hypothesis that DRN causes DR. If confirmed, this new paradigm may lead to earlier detection of ocular diabetic damage and earlier treatment of early DR, thereby preventing visual loss in people with diabetes.

Altered eigenvector centrality is related to local resting-state network functional connectivity in patients with longstanding type 1 diabetes mellitus

INTRODUCTION

Longstanding type 1 diabetes (T1DM) is associated with microangiopathy and poorer cognition. In the brain, T1DM is related to increased functional resting-state network (RSN) connectivity in patients without, which was decreased in patients with clinically evident microangiopathy. Subcortical structure seems affected in both patient groups. How these localized alterations affect the hierarchy of the functional network in T1DM is unknown. Eigenvector centrality mapping (ECM) and degree centrality are graph theoretical methods that allow determining the relative importance (ECM) and connectedness (degree centrality) of regions within the whole-brain network hierarchy.

METHODS

Therefore, ECM and degree centrality of resting-state functional MRI-scans were compared between 51 patients with, 53 patients without proliferative retinopathy, and 49 controls, and associated with RSN connectivity, subcortical gray matter volume, and cognition.

RESULTS

In all patients versus controls, ECM and degree centrality were lower in the bilateral thalamus and the dorsal striatum, with lowest values in patients without proliferative retinopathy (P_FWE  < 0.05). Increased ECM in this group versus patients with proliferative retinopathy was seen in the bilateral lateral occipital cortex, and in the right cuneus and occipital fusiform gyrus versus controls (P_FWE  < 0.05). In all patients, ECM and degree centrality were related to altered visual, sensorimotor, and auditory and language RSN connectivity (P_FWE  < 0.05), but not to subcortical gray matter volume or cognition (P_FDR  > 0.05).

CONCLUSION

The findings suggested reorganization of the hierarchy of the cortical connectivity network in patients without proliferative retinopathy, which is lost with disease progression. Centrality seems sensitive to capture early T1DM-related functional connectivity alterations, but not disease progression. Hum Brain Mapp 38:3623-3636, 2017. © 2017 Wiley Periodicals, Inc.

Putamen volume and its clinical and neurological correlates in primary HIV infection

OBJECTIVE

Little is known about the extent of cortical and subcortical volumetric alterations that may occur within the first year of HIV infection [primary HIV infection (PHI)].

DESIGN

We used structural MRI in this prospective cross-sectional neuroimaging study to determine the extent of volumetric changes in early HIV infection.

METHODS

Cerebrospinal fluid, blood, neuropsychological testing, and structural T1 MRI scans were acquired from 18 HIV and 47 PHI age-matched antiretroviral-naïve male participants. Using FreeSurfer 5.1, volumetric measurements were obtained from the caudate, amygdala, corpus callosum, ventricles, putamen, thalamus, cortical white matter, and total gray matter. Regional volumes were compared groupwise and related to biomarkers in cerebrospinal fluid (viral load, neopterin, and neurofilament light chain), blood (viral load, CD4, and CD8 T-cell count), and neuropsychometric tests (digit-symbol, grooved pegboard, finger-tapping, and timed gait).

RESULTS

A trend-level moderate reduction of putamen volume (P = 0.076, adjusted Cohen's d = 0.5 after controlling for age) was observed for PHI compared with HIV-uninfected individuals. Within the PHI group, putamen volume associated with CD4 cell count (P = 0.03), CD4/CD8 ratio (P = 0.045), infection duration (P = 0.009), and worsening psychomotor performance on the digit-symbol (P = 0.028), finger-tapping (P = 0.039), and timed gait (P = 0.009) tests.

CONCLUSION

Our volumetric results suggest that the putamen is preferentially susceptible to early HIV-associated processes. Examining the natural course of early HIV infection longitudinally will allow for mapping of the trajectory of HIV-associated central nervous system changes, enabling creation of improved interventional strategies to potentially stabilize or reverse these observed structural changes.

Subgenual Cingulate Cortex Functional Connectivity in Relation to Depressive Symptoms and Cognitive Functioning in Type 1 Diabetes Mellitus Patients

OBJECTIVES

Patients with Type 1 diabetes mellitus (T1DM) are at an increased risk for major depression, but its underlying mechanisms are still poorly understood. In nondiabetic participants, mood disturbances are related to altered subgenual cingulate cortex (SGC) resting-state functional connectivity. We tested for SGC connectivity alterations in T1DM, whether these alterations were related to depressive symptoms, and if depressive symptoms were associated with cognition.

METHODS

A bilateral SGC seed-based resting-state functional magnetic resonance imaging analysis was performed in 104 T1DM patients and 49 controls without known psychiatric diagnosis or treatment. Depressive symptoms were self-reported using the Center for Epidemiological Studies Depression scale. Cognition was assessed with a battery of standardized tests.

RESULTS

In patients versus controls, SGC to right inferior frontal gyrus and frontal pole connectivity was decreased (52 voxels, z valuepeak = 3.56, pcluster-FWE = .002), whereas SGC to bilateral precuneus (33 voxels, z valuepeak = 3.34, pcluster-FWE = .04) and left inferior parietal lobule (50 voxels, z valuepeak = 3.50, pcluster-FWE = .003) connectivity was increased. In all participants, increased depressive symptoms was related to lower SGC to inferior frontal gyrus and frontal pole connectivity (β = -0.156, p = .053), and poorer general cognitive ability (β = -0.194, p = .023), information processing speed (β = -0.222, p = .008), and motor speed (β = -0.180, p = .035).

CONCLUSIONS

T1DM patients showed a pattern of SGC connectivity that is characterized by lower executive control and higher default mode network connectivity. Depressive symptoms are partially related to these alterations and seem to exacerbate T1DM-related cognitive dysfunction. Future studies should detail the effect of diagnosed major depressive disorder in this population and establish what alterations are diabetes specific.

The Association of Type 2 Diabetes Mellitus with Cerebral Gray Matter Volume Is Independent of Retinal Vascular Architecture and Retinopathy

It is uncertain whether small vessel disease underlies the relationship between Type 2 Diabetes Mellitus (T2DM) and brain atrophy. We aimed to study whether retinal vascular architecture, as a proxy for cerebral small vessel disease, may modify or mediate the associations of T2DM with brain volumes. In this cross-sectional study using Magnetic Resonance Imaging (MRI) scans and retinal photographs in 451 people with and without T2DM, we measured brain volumes, geometric measures of retinal vascular architecture, clinical retinopathy, and MRI cerebrovascular lesions. There were 270 people with (mean age 67.3 years) and 181 without T2DM (mean age 72.9 years). T2DM was associated with lower gray matter volume (p = 0.008). T2DM was associated with greater arteriolar diameter (p = 0.03) and optimality ratio (p = 0.04), but these associations were attenuated by adjustments for age and sex. Only optimality ratio was associated with lower gray matter volume (p = 0.03). The inclusion of retinal measures in regression models did not attenuate the association of T2DM with gray matter volume. The association of T2DM with lower gray matter volume was independent of retinal vascular architecture and clinical retinopathy. Retinal vascular measures or retinopathy may not be sufficiently sensitive to confirm a microvascular basis for T2DM-related brain atrophy.

Disrupted subject-specific gray matter network properties and cognitive dysfunction in type 1 diabetes patients with and without proliferative retinopathy

INTRODUCTION

Type 1 diabetes mellitus (T1DM) patients, especially with concomitant microvascular disease, such as proliferative retinopathy, have an increased risk of cognitive deficits. Local cortical gray matter volume reductions only partially explain these cognitive dysfunctions, possibly because volume reductions do not take into account the complex connectivity structure of the brain. This study aimed to identify gray matter network alterations in relation to cognition in T1DM.

METHODS

We investigated if subject-specific structural gray matter network properties, constructed from T1-weighted MRI scans, were different between T1DM patients with (n = 51) and without (n = 53) proliferative retinopathy versus controls (n = 49), and were associated to cognitive decrements and fractional anisotropy, as measured by voxel-based TBSS. Global normalized and local (45 bilateral anatomical regions) clustering coefficient and path length were assessed. These network properties measure how the organization of connections in a network differs from that of randomly connected networks.

RESULTS

Global gray matter network topology was more randomly organized in both T1DM patient groups versus controls, with the largest effects seen in patients with proliferative retinopathy. Lower local path length values were widely distributed throughout the brain. Lower local clustering was observed in the middle frontal, postcentral, and occipital areas. Complex network topology explained up to 20% of the variance of cognitive decrements, beyond other predictors. Exploratory analyses showed that lower fractional anisotropy was associated with a more random gray matter network organization.

CONCLUSION

T1DM and proliferative retinopathy affect cortical network organization that may consequently contribute to clinically relevant changes in cognitive functioning in these patients.

Patients with type 1 diabetes in Sweden experience more fatigue than the general population

Aims

Type 2 diabetes has been linked to fatigue, but results on type 1 diabetes are ambiguous. Our aim was to determine if type 1 diabetes is associated with fatigue and whether the fatigue is due to complications or to the disease itself.

Methods

The Multidimensional Fatigue Inventory (MFI-20), was submitted to all 435 adult patients with type 1 diabetes in the National Diabetes Register at the Sunderby Hospital clinic and to a control group of 2500 persons. The participation rate was 62% in both groups.

Results

Type 1 diabetes was associated with greater fatigue, with a 1.4-point difference (0.9–1.9, 95% CI) in general fatigue on a scale of 4–20. Type 1 diabetes was an independent predictor of fatigue, as were cardiovascular and cerebrovascular disease. Women with long diabetes duration but without complications experienced more fatigue than women in the general population (difference in general fatigue = 2.5, p = 0.021), whereas men showed no significant difference.

Conclusions

Type 1 diabetes is associated with greater fatigue, partly ascribed to vascular disease. Type 1 diabetes of long duration might be associated with fatigue regardless of classical complications, but further research is needed to confirm results.