Relationship Between Type 2 Diabetes and White Matter Hyperintensity: A Systematic Review

Framingham Stroke Risk Profile Score and White Matter Disease Progression

OBJECTIVES

To evaluate the relationship between Framingham Stroke Risk Profile (FSRP) score and rate of white matter hyperintensity (WMH) progression and cognition.

METHODS

Consecutive patients enrolled in the Mayo Clinic Florida Familial Cerebrovascular Diseases Registry (2011-2020) with 2 brain-MRI scans at least 1 year apart were included. The primary outcome was annual change in WMH volume (cm3/year) stratified as fast versus slow (above vs. below median). Cognition was assessed using a Mini-Mental State Exam (MMSE, 0-30). FSRP score (0 to 8) was calculated by summing the presence of age 65 years or older, smoking, systolic blood pressure greater than 130 mmHg, diabetes, coronary disease, atrial fibrillation, left ventricular hypertrophy, and antihypertensive medication use. Linear and logistic regression analyses were performed to examine the association between FSRP and WMH progression, and cognition.

RESULTS

In all, 207 patients were included, with a mean age of 60±16 y and 54.6% female. FSRP scores risk distribution was: 31.9% scored 0 to 1, 36.7% scored 2 to 3, and 31.4% scored ≥4. The baseline WMH volume was 9.6 cm3 (IQR: 3.3-28.4 cm3), and the annual rate of WMH progression was 0.9 cm3/year (IQR: 0.1 to 3.1 cm3/year). A higher FSRP score was associated with fast WMH progression (odds ratio, 1.45; 95% CI: 1.22-1.72; P<0.001) and a lower MMSE score (23.6 vs. 27.1; P<0.001). There was a dose-dependent relationship between higher FSRP score and fast WMH progression (odds ratios, 2.20, 4.64, 7.86, 8.03 for FSRP scores 1, 2, 3, and ≥4, respectively; trend P<0.001).

CONCLUSIONS

This study demonstrated an association between higher FSRP scores and accelerated WMH progression, as well as lower cognition.

Sleep-wake behaviors associated with cognitive performance in middle-aged participants of the Hispanic Community Health Study/Study of Latinos

OBJECTIVES

Many sleep-wake behaviors have been associated with cognition. We examined a panel of sleep-wake/activity characteristics to determine which are most robustly related to having low cognitive performance in midlife. Secondarily, we evaluate the predictive utility of sleep-wake measures to screen for low cognitive performance.

METHODS

The outcome was low cognitive performance defined as being >1 standard deviation below average age/sex/education internally normalized composite cognitive performance levels assessed in the Hispanic Community Health Study/Study of Latinos. Analyses included 1006 individuals who had sufficient sleep-wake measurements about 2years later (mean age=54.9, standard deviation= 5.1; 68.82% female). We evaluated associations of 31 sleep-wake variables with low cognitive performance using separate logistic regressions.

RESULTS

In individual models, the strongest sleep-wake correlates of low cognitive performance were measures of weaker and unstable 24-hour rhythms; greater 24-hour fragmentation; longer time-in-bed; and lower rhythm amplitude. One standard deviation worse on these sleep-wake factors was associated with ∼20%-30% greater odds of having low cognitive performance. In an internally cross-validated prediction model, the independent correlates of low cognitive performance were: lower Sleep Regularity Index scores; lower pseudo-F statistics (modellability of 24-hour rhythms); lower activity rhythm amplitude; and greater time in bed. Area under the curve was low/moderate (64%) indicating poor predictive utility.

CONCLUSION

The strongest sleep-wake behavioral correlates of low cognitive performance were measures of longer time-in-bed and irregular/weak rhythms. These sleep-wake assessments were not useful to identify previous low cognitive performance. Given their potential modifiability, experimental trials could test if targeting midlife time-in-bed and/or irregular rhythms influences cognition.

Sex Specific Associations of Sex hormone With Brain Volumes and Cerebral Blood Flow: A Cross Sectional Observational Study Within the Look AHEAD Type 2 Diabetes Cohort

Background

Females have greater brain volume and cerebral blood flow than males when controlling for intracranial volume and age. Brain volume decreases after menopause, suggesting a role of sex hormones. We studied the association of sex hormones with brain volume, white matter hyperintensity volumes and cerebral blood flow in people with Type 2 Diabetes and with overweight and obesity conditions that accelerate brain atrophy.

Methods

We analyzed data from 215 participants with overweight or obesity and Type 2 Diabetes from the Look AHEAD Brain Magnetic Resonance Imaging ancillary study (mean age 68 years, 73% postmenopausal female). Estradiol and total testosterone levels were measured with electrochemoluminescence assays. The ratio of brain measurements to intracranial volume was analyzed to account for body size. We analyzed sex hormones as quantitative measures in males, whereas in females we grouped those with detectable vs. undetectable hormone levels (Estradiol <73 pmol/L [20 pg/mL]: 79%; Total Testosterone < 0.07 mmol/L [0.02 ng/mL]: 37% undetectable in females).

Results

Females with detectable total testosterone levels had higher brain volume to intracranial volume ratio (median [25th, 75th percentile]: 0.85 [0.84, 0.86]) as compared to those with undetectable Total Testosterone levels (0.84 [0.83, 0.86]; rank sum p=0.04). This association was attenuated after age and body mass index adjustment (p=0.08). Neither white matter hyperintensity volumes or cerebral blood flow in females, nor any brain measures in males, were significantly associated with Estradiol or Total Testosterone.

Conclusions

In postmenopausal females with Type 2 Diabetes with overweight and obesity, detectable levels of total testosterone were associated greater brain volume relative to intracranial volume, suggesting a protective role for testosterone in female brain health. Our findings are limited by a small sample size and low sensitivity of hormone assays. Our suggestive findings can be combined with future larger studies to assess clinically important differences.

Trial Registration

NCT00017953.

ECHDC3 Variant Regulates the Right Hippocampal Microstructural Integrity and Verbal Memory in Type 2 Diabetes Mellitus

ECHDC3 is a risk gene for white matter (WM) hyperintensity and is associated with insulin resistance. This study aimed to investigate whether ECHDC3 variants selectively regulate brain WM microstructures and episodic memory in patients with type 2 diabetes mellitus (T2DM). We enrolled 106 patients with T2DM and 111 healthy controls. A voxel-wise general linear model was employed to explore the interaction effect between ECHDC3 rs11257311 polymorphism and T2DM diagnosis on fractional anisotropy (FA). A linear modulated mediation analysis was conducted to examine the potential of FA value to mediate the influence of T2DM on episodic memory in an ECHDC3-dependent manner. We observed a noteworthy interaction between genotype and diagnosis on FA in the right inferior temporal WM, right anterior limb of the internal capsule, right frontal WM, and the right hippocampus. Modulated mediation analysis revealed a significant ECHDC3 modulation on the T2DM → right hippocampal FA → short-term memory pathway, with only rs11257311 G risk homozygote demonstrating significant mediation effect. Together, our findings provide evidence of ECHDC3 modulating the effect of T2DM on right hippocampal microstructural impairment and short-term memory decline, which might be a neuro-mechanism for T2DM related episodic memory impairment.

MRI features and disability in multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

In this systematic review and meta-analysis, we aimed to investigate the correlation between disability in patients with Multiple sclerosis (MS) measured by the Expanded Disability Status Scale (EDSS) and brain Magnetic Resonance Imaging (MRI) features to provide reliable results on which characteristics in the MRI can predict disability and prognosis of the disease.

METHODS

A systematic literature search was performed using three databases including PubMed, Scopus, and Web of Science. The selected peer-reviewed studies must report a correlation between EDSS scores and MRI features. The correlation coefficients of included studies were converted to the Fisher's z scale, and the results were pooled.

RESULTS

Overall, 105 studies A total of 16,613 patients with MS entered our study. We found no significant correlation between total brain volume and EDSS assessment (95 % CI: -0.37 to 0.08; z-score: -0.15). We examined the potential correlation between the volume of T1 and T2 lesions and the level of disability. A positive significant correlation was found (95 % CI: 0.19 to 0.43; z-score: 0.31), (95 % CI: 0.17 to 0.33; z-score: 0.25). We observed a significant correlation between white matter volume and EDSS score in patients with MS (95 % CI: -0.37 to -0.03; z-score: -0.21). Moreover, there was a significant negative correlation between gray matter volume and disability (95 % CI: -0.025 to -0.07; z-score: -0.16).

CONCLUSION

In conclusion, this systematic review and meta-analysis revealed that disability in patients with MS is linked to extensive changes in different brain regions, encompassing gray and white matter, as well as T1 and T2 weighted MRI lesions.

Diabetes, antidiabetic medications and risk of dementia: A systematic umbrella review and meta-analysis

AIMS

The objective of this umbrella review and meta-analysis was to evaluate the effect of diabetes on risk of dementia, as well as the mitigating effect of antidiabetic treatments.

MATERIALS AND METHODS

We conducted a systematic umbrella review on diabetes and its treatment, and a meta-analysis focusing on treatment. We searched MEDLINE/PubMed, Embase, PsycINFO, CINAHL and the Cochrane Library for systematic reviews and meta-analyses assessing the risk of cognitive decline/dementia in individuals with diabetes until 2 July 2023. We conducted random-effects meta-analyses to obtain risk ratios and 95% confidence intervals estimating the association of metformin, thiazolidinediones, pioglitazone, dipeptidyl peptidase-4 inhibitors, α-glucosidase inhibitors, meglitinides, insulin, sulphonylureas, glucagon-like peptide-1 receptor agonists (GLP1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2is) with risk of dementia from cohort/case-control studies. The subgroups analysed included country and world region. Risk of bias was assessed with the AMSTAR tool and Newcastle-Ottawa Scale.

RESULTS

We included 100 reviews and 27 cohort/case-control studies (N = 3 046 661). Metformin, thiazolidinediones, pioglitazone, GLP1RAs and SGLT2is were associated with significant reduction in risk of dementia. When studies examining metformin were divided by country, the only significant effect was for the United States. Moreover, the effect of metformin was significant in Western but not Eastern populations. No significant effect was observed for dipeptidyl peptidase-4 inhibitors, α-glucosidase inhibitors, or insulin, while meglitinides and sulphonylureas were associated with increased risk.

CONCLUSIONS

Metformin, thiazolidinediones, pioglitazone, GLP1RAs and SGLT2is were associated with reduced risk of dementia. More longitudinal studies aimed at determining their relative benefit in different populations should be conducted.

Association between brain imaging biomarkers and continuous glucose monitoring-derived glycemic control indices in Japanese patients with type 2 diabetes mellitus

INTRODUCTION

Although type 2 diabetes mellitus (T2DM) is associated with alterations in brain structure, the relationship between glycemic control indices and brain imaging markers remains unclear. This study aimed to investigate the association between continuous glucose monitoring (CGM)-derived glycemic control indices and brain imaging biomarkers assessed by MRI.

RESEARCH DESIGN AND METHODS

This cross-sectional study included 150 patients with T2DM. The severity of cerebral white matter lesions (WMLs) was assessed using MRI for deep and subcortical white matter and periventricular hyperintensities. The degree of medial temporal lobe atrophy (MTA) was assessed using voxel-based morphometry. Each participant wore a retrospective CGM for 14 consecutive days, and glycemic control indices, such as time in range (TIR) and glycemia risk index (GRI), were calculated.

RESULTS

The proportion of patients with severe WMLs showed a decreasing trend with increasing TIR (P for trend=0.006). The proportion of patients with severe WMLs showed an increasing trend with worsening GRI (P for trend=0.011). In contrast, no significant association was observed between the degree of MTA and CGM-derived glycemic control indices, including TIR (P for trend=0.325) and GRI (P for trend=0.447).

CONCLUSIONS

The findings of this study indicate that the severity of WMLs is associated with TIR and GRI, which are indices of the quality of glycemic control.

TRIAL REGISTRATION NUMBER

UMIN000032143.

Risk factors and cognitive correlates of white matter hyperintensities in ethnically diverse populations without dementia: The COSMIC consortium

INTRODUCTION

White matter hyperintensities (WMHs) are an important imaging marker for cerebral small vessel diseases, but their risk factors and cognitive associations have not been well documented in populations of different ethnicities and/or from different geographical regions.

METHODS

We investigated how WMHs were associated with vascular risk factors and cognition in both Whites and Asians, using data from five population-based cohorts of non-demented older individuals from Australia, Singapore, South Korea, and Sweden (N = 1946). WMH volumes (whole brain, periventricular, and deep) were quantified with UBO Detector and harmonized using the ComBat model. We also harmonized various vascular risk factors and scores for global cognition and individual cognitive domains.

RESULTS

Factors associated with larger whole brain WMH volumes included diabetes, hypertension, stroke, current smoking, body mass index, higher alcohol intake, and insufficient physical activity. Hypertension and stroke had stronger associations with WMH volumes in Whites than in Asians. No associations between WMH volumes and cognitive performance were found after correction for multiple testing.

CONCLUSION

The current study highlights ethnic differences in the contributions of vascular risk factors to WMHs.

Nonhypertensive White Matter Hyperintensities in Stroke: Risk Factors, Neuroimaging Characteristics, and Prognosis

BACKGROUND

This study explored the risk factors, neuroimaging features, and prognostic implications of nonhypertensive white matter hyperintensity (WMH) in patients with acute ischemic stroke and transient ischemic attack.

METHODS AND RESULTS

We included 2283 patients with hypertension and 1003 without from a pool of 10 602. Associations of moderate-to-severe WMH with known risk factors, functional outcome, and a composite of recurrent stroke, myocardial infarction, and all-cause mortality were evaluated. A subset of 351 patients without hypertension and age- and sex-matched pairs with hypertension and moderate-to-severe WMH was created for a detailed topographic examination of WMH, lacunes, and microbleeds. Approximately 35% of patients without hypertension and 65% of patients with hypertensive stroke exhibited moderate-to-severe WMH. WMH was associated with age, female sex, and previous stroke, irrespective of hypertension. In patients without hypertension, WMH was associated with initial systolic blood pressure and was more common in the anterior temporal region. In patients with hypertension, WMH was associated with small vessel occlusion as a stroke mechanism and was more frequent in the periventricular region near the posterior horn of the lateral ventricle. The higher prevalence of occipital microbleeds in patients without hypertension and deep subcortical lacunes in patients with hypertension were also observed. Associations of moderate-to-severe WMH with 3-month functional outcome and 1-year cumulative incidence of the composite outcome were significant (both P<0.01), although the latter lost significance after adjustments. The associations between WMH and outcomes were consistent across hypertensive status.

CONCLUSIONS

One-third of patients without hypertension with stroke have moderate-to-severe WMH. The pathogenesis of WMH may differ between patients without and with hypertension, but its impact on outcome appears similar.

Retinal ganglion cell-inner plexiform layer, white matter hyperintensities, and their interaction with cognition in older adults

Purpose

We explored the interaction of optical coherence tomography (OCT) parameters and white matter hyperintensities with cognitive measures in our older adult cohort.

Methods

This observational study enrolled participants who underwent a comprehensive neuropsychological battery, structural 3-T brain magnetic resonance imaging (MRI), visual acuity examination, and OCT imaging. Cerebral small vessel disease (CSVD) markers were read on MR images; lacune, cerebral microbleeds (CMB), white matter hyperintensities (WMH), and enlarged perivascular spaces (EPVS), were defined according to the STRIVE standards. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses (μm) were measured on the OCT tool.

Results

Older adults with cognitive impairment (CI) showed lower RNFL (p = 0.001), GCIPL (p = 0.009) thicknesses, and lower hippocampal volume (p = 0.004) when compared to non-cognitively impaired (NCI). RNFL (p = 0.006) and GCIPL thicknesses (p = 0.032) correlated with MoCA scores. GCIPL thickness (p = 0.037), total WMH (p = 0.003), PWMH (p = 0.041), and DWMH (p = 0.001) correlated with hippocampal volume in our older adults after adjusting for covariates. With hippocampal volume as the outcome, a significant interaction (p < 0.05) between GCIPL and PWMH and total WMH was observed in our older adults.

Conclusion

Both GCIPL thinning and higher WMH burden (especially PWMH) are associated with hippocampal volume and older adults with both pathologies are more susceptible to subclinical cognitive decline.

Diabetic microvascular disease in non-classical beds: the hidden impact beyond the retina, the kidney, and the peripheral nerves

Diabetes microangiopathy, a hallmark complication of diabetes, is characterised by structural and functional abnormalities within the intricate network of microvessels beyond well-known and documented target organs, i.e., the retina, kidney, and peripheral nerves. Indeed, an intact microvascular bed is crucial for preserving each organ's specific functions and achieving physiological balance to meet their respective metabolic demands. Therefore, diabetes-related microvascular dysfunction leads to widespread multiorgan consequences in still-overlooked non-traditional target organs such as the brain, the lung, the bone tissue, the skin, the arterial wall, the heart, or the musculoskeletal system. All these organs are vulnerable to the physiopathological mechanisms that cause microvascular damage in diabetes (i.e., hyperglycaemia-induced oxidative stress, inflammation, and endothelial dysfunction) and collectively contribute to abnormalities in the microvessels' structure and function, compromising blood flow and tissue perfusion. However, the microcirculatory networks differ between organs due to variations in haemodynamic, vascular architecture, and affected cells, resulting in a spectrum of clinical presentations. The aim of this review is to focus on the multifaceted nature of microvascular impairment in diabetes through available evidence of specific consequences in often overlooked organs. A better understanding of diabetes microangiopathy in non-target organs provides a broader perspective on the systemic nature of the disease, underscoring the importance of recognising the comprehensive range of complications beyond the classic target sites.

Risk factors and cognitive correlates of white matter hyperintensities in ethnically diverse populations without dementia: the COSMIC consortium

INTRODUCTION

White matter hyperintensities (WMH) are an important imaging marker for cerebral small vessel diseases, but their risk factors and cognitive associations have not been well-documented in populations of different ethnicities and/or from different geographical regions.

METHOD

Magnetic resonance imaging data of five population-based cohorts of non-demented older individuals from Australia, Singapore, South Korea, and Sweden (N = 1,946) were examined for WMH and their associations with vascular risk factors and cognition.

RESULT

Factors associated with larger whole brain WMH volumes included diabetes, hypertension, stroke, current smoking, body mass index, higher alcohol intake and insufficient physical activity. Participants with moderate or higher physical activity had less WMH than those who never exercised, but the former two groups did not differ. Hypertension and stroke had stronger associations with WMH volumes in the White, compared to Asian subsample.

DISCUSSION

The current study highlighted the ethnic differences in the contributions of vascular risk factors to WMH.

Cerebral small vessel disease pathology in COVID-19 patients: A systematic review

Cerebral small vessel disease (CSVD) is the leading cause of vascular cognitive impairment and is associated with COVID-19. However, contributing factors that often accompany CSVD pathology in COVID-19 patients may influence the incidence of cerebrovascular complications. Thus, a mechanism linking COVID-19 and CSVD has yet to be uncovered and differentiated from age-related comorbidities (i.e., hypertension), and medical interventions during acute infection. We aimed to evaluate CSVD in acute and recovered COVID-19 patients and to differentiate COVID-19-related cerebrovascular pathology from the above-mentioned contributing factors by assessing the localization of microbleeds and ischemic lesions/infarctions in the cerebrum, cerebellum, and brainstem. A systematic search was performed in December 2022 on PubMed, Web of Science, and Embase using a pre-established search criterion related to history of, or active COVID-19 with CSVD pathology in adults. From a pool of 161 studies, 59 met eligibility criteria and were included. Microbleeds and ischemic lesions had a strong predilection for the corpus callosum and subcortical/deep white matter in COVID-19 patients, suggesting a distinct CSVD pathology. These findings have important implications for clinical practice and biomedical research as COVID-19 may independently, and through exacerbation of age-related mechanisms, contribute to increased incidence of CSVD.

Predicting cerebral white matter lesions based on the platelet-to-white blood cell ratio in hypertensive patients

Hypertension is a common chronic disease affecting many people. White matter lesions (WMLs) are one of the imaging features of cerebrovascular disease. Predicting the possibility of developing syncretic WMLs in patients with hypertension may contribute to the early identification of serious clinical conditions. This study aims to build a model to identify patients who suffered from moderate-to-severe WMLs by using recognized WMLs risk factors including age and history of diabetes and a new factor named platelet-to-white blood cell ratio (PWR). A total of 237 patients were included in this study. The Affiliated ZhongDa Hospital of Southeast University Research Ethics Committee approved this study (Ethics No. 2019ZDSYLL189-P01). We developed a nomogram to predict the risk of syncretic WMLs in patients with hypertension using the above factors. Higher total scores on the nomogram indicated a higher risk of syncretic WMLs. This means older age, smaller PWR, and patients suffering from diabetes contributed to a greater chance for the patient to suffer from syncretic WMLs. We used a decision analysis curve(DCA) to determine the net benefit of the prediction model. The DCA we constructed showed that using our model to decide whether patients suffered from syncretic WMLs or not was better than assuming they all suffered from syncretic WMLs or all WMLs-free. As a result, the area under the curve of our model was 0.787. By integrating PWR, history of diabetes, and age, we could estimate integrated WMLs in hypertensive patients. This study provides a potential tool to identify cerebrovascular disease in patients with hypertension.

Sex differences in the effects of high fat diet on underlying neuropathology in a mouse model of VCID

BACKGROUND

Damage to the cerebral vasculature can lead to vascular contributions to cognitive impairment and dementia (VCID). A reduction in blood flow to the brain leads to neuropathology, including neuroinflammation and white matter lesions that are a hallmark of VCID. Mid-life metabolic disease (obesity, prediabetes, or diabetes) is a risk factor for VCID which may be sex-dependent (female bias).

METHODS

We compared the effects of mid-life metabolic disease between males and females in a chronic cerebral hypoperfusion mouse model of VCID. C57BL/6J mice were fed a control or high fat (HF) diet starting at ~ 8.5 months of age. Three months after diet initiation, sham or unilateral carotid artery occlusion surgery (VCID model) was performed. Three months later, mice underwent behavior testing and brains were collected to assess pathology.

RESULTS

We have previously shown that in this VCID model, HF diet causes greater metabolic impairment and a wider array of cognitive deficits in females compared to males. Here, we report on sex differences in the underlying neuropathology, specifically white matter changes and neuroinflammation in several areas of the brain. White matter was negatively impacted by VCID in males and HF diet in females, with greater metabolic impairment correlating with less myelin markers in females only. High fat diet led to an increase in microglia activation in males but not in females. Further, HF diet led to a decrease in proinflammatory cytokines and pro-resolving mediator mRNA expression in females but not males.

CONCLUSIONS

The current study adds to our understanding of sex differences in underlying neuropathology of VCID in the presence of a common risk factor (obesity/prediabetes). This information is crucial for the development of effective, sex-specific therapeutic interventions for VCID.

Changes in Cognition and Brain Function After 26 Weeks of Progressive Resistance Training in Older Adults at Risk for Diabetes: A Pilot Randomized Controlled Trial

OBJECTIVES

Type 2 diabetes is associated with deficits in cognition and brain health. Individuals with at least 1 risk factor for diabetes (i.e. obesity, prediabetes) already experience some neurocognitive impairment and are at risk for further decline. One way to combat these deficits is through exercise, but its is unknown whether resistance exercise can improve these functions in this at-risk group.

METHODS

This study was a pilot randomized controlled trial. Participants were 60 to 80 years of age and had prediabetes (fasting capillary glucose 6.1 to 6.9 mmol/L) and/or were overweight or obese (body mass index ≥25). Participants completed resistance training or balance and stretching exercise (control) thrice weekly for 6 months. Neuropsychological tests were used to assess cognitive ability, whereas functional magnetic resonance imaging was used to examine brain activation patterns.

RESULTS

Resistance training led to improvements in task-switching, attention and conflict resolution, as well as improved patterns of brain activation that may mimic healthy older adults.

CONCLUSIONS

Resistance exercise may serve as an effective behavioural strategy to improve neurocognition in older adults at risk for type 2 diabetes. A large-scale powered trial is needed to further explore these findings.

Metabolic profile-based subgroups can identify differences in brain volumes and brain iron deposition

AIMS

To evaluate associations of metabolic profiles and biomarkers with brain atrophy, lesions, and iron deposition to understand the early risk factors associated with dementia.

MATERIALS AND METHODS

Using data from 26 239 UK Biobank participants free from dementia and stroke, we assessed the associations of metabolic subgroups, derived using an artificial neural network approach (self-organizing map), and 39 individual biomarkers with brain MRI measures: total brain volume (TBV), grey matter volume (GMV), white matter volume (WMV), hippocampal volume (HV), white matter hyperintensity (WMH) volume, and caudate iron deposition.

RESULTS

In metabolic subgroup analyses, participants characterized by high triglycerides and liver enzymes showed the most adverse brain outcomes compared to the healthy reference subgroup with high-density lipoprotein cholesterol and low body mass index (BMI) including associations with GMV (βstandardized -0.20, 95% confidence interval [CI] -0.24 to -0.16), HV (βstandardized -0.09, 95% CI -0.13 to -0.04), WMH volume (βstandardized 0.22, 95% CI 0.18 to 0.26), and caudate iron deposition (βstandardized 0.30, 95% CI 0.25 to 0.34), with similar adverse associations for the subgroup with high BMI, C-reactive protein and cystatin C, and the subgroup with high blood pressure (BP) and apolipoprotein B. Among the biomarkers, striking associations were seen between basal metabolic rate (BMR) and caudate iron deposition (βstandardized 0.23, 95% CI 0.22 to 0.24 per 1 SD increase), GMV (βstandardized -0.15, 95% CI -0.16 to -0.14) and HV (βstandardized -0.11, 95% CI -0.12 to -0.10), and between BP and WMH volume (βstandardized 0.13, 95% CI 0.12 to 0.14 for diastolic BP).

CONCLUSIONS

Metabolic profiles were associated differentially with brain neuroimaging characteristics. Associations of BMR, BP and other individual biomarkers may provide insights into actionable mechanisms driving these brain associations.

Prevalence and clinical characteristics of white matter hyperintensities in Migraine: A meta-analysis

BACKGROUND

Current evidences show an increased risk of white matter hyperintensities (WMHs) in migraineurs compared to age-matched controls. However, WMHs prevalence and the associations between WMHs and clinical characteristics in migraineurs have not been systematically evaluated using a meta-analytical approach. This study explored the pooled prevalence of WMHs and the associations of WMHs with the clinical characteristics in patients with migraine.

METHODS

A systematic review and meta-analysis of observational studies reporting the occurrence and clinical characteristics of patients with WMHs attributed to migraine was performed. We searched the PubMed, Web of Science, and Embase databases. Random-effects models were used to calculate the pooled prevalence rate, odds ratio (OR), or mean difference (MD) with corresponding 95% confidence intervals (CIs).

RESULTS

Thirty eligible studies were identified including 3,502 migraineurs aged 37.2 (mean) years. The pooled WMHs prevalence was 44 %, 45 %, and 38 % in migraine, migraine with aura, and migraine without aura groups, respectively. In migraineurs with WMHs, the frontal lobe and subcortical white matter were the most susceptible area. Compared with non-migraine controls, patients with migraine had increased odds for WMHs (OR 4.32, 95 % CI = 2.56-7.28, I² = 67 %). According to reported univariable results from included studies, pooled analysis showed that clinical characteristics including age, presence of aura, disease duration, hypertension, diabetes mellitus and right-to-left shunt were associated with the presence of WMHs. Migraine pain and aura characteristics were not related to WMHs.

CONCLUSIONS

These data suggest that WMHs are common in migraine, especially in those who are older or have aura, hypertension, diabetes mellitus, or right-to-left shunt. A better understanding of the WMHs attributed to migraine is needed in future studies.

Effects of reducing sedentary behaviour duration by increasing physical activity, on cognitive function, brain function and structure across the lifespan: a systematic review protocol

INTRODUCTION

Greater engagement in sedentary behaviours has been related to poorer cognitive functions in epidemiological research. However, the effects of reducing sedentary behaviour duration on cognitive function, brain function, and structure remain poorly understood. This systematic review aims to synthesise the evidence on the effects of reducing sedentary behaviour duration by increasing time spent in physical activity on cognitive function, brain structure and function in apparently healthy children, adolescents and adults.

METHODS AND ANALYSIS

The protocol follows Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The literature search will be conducted (search dates: August-September 2022) across six databases: PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (via EBSCO Host), PsycINFO (via ProQuest), SPORTDiscus and Web of Science (Science and Social Science Citation Index). The inclusion criteria are as follows: randomised and non-randomised experimental studies as defined by the Cochrane Handbook, published in English, in peer-reviewed journals, and as theses or dissertations. References of included papers will be screened for additional studies. Acute and chronic interventions targeting children (≥ 4 years), adolescents, younger adults (≥ 18-40 years), middle-aged (40-64 years) and older adults (65+ years) will be eligible. Methodological quality will be assessed with the Effective Public Health Practice Project quality assessment tool for quantitative studies. Qualitative synthesis will be stratified by intervention type (acute vs chronic), intervention content (reducing sedentary time or interrupting prolonged sitting) and outcome (cognitive, brain structure and function).

ETHICS AND DISSEMINATION

No primary data collection will be conducted as part of this systematic review. Study findings will be disseminated through peer-reviewed publications, conference presentations and social media.

PROSPERO REGISTRATION NUMBER

CRD42020200998.

Genetic and Environmental Effects on the Development of White Matter Hyperintensities in a Middle Age Twin Population

Introduction: White matter hyperintensities (WMH) indicate white matter brain lesions in magnetic resonance imaging (MRI), which can be used as a marker for brain aging and cerebrovascular and neurodegenerative disorders. Twin studies revealed substantial but not uniform WMH heritability in elderly twins. The objective of our study was to investigate the genetic and environmental components of WMH, as well as their importance in a healthy twin population, utilizing 3T MRI scanners in a middle-aged twin population. Methods: Brain MRI was performed on 120 healthy adult twins from the Hungarian Twin Registry on a 3T scanner (86 monozygotic, MZ and 34 dizygotic, DZ twins; median age 50 ± 26.5 years, 72.5% female and 27.5% male). The count of WMH on FLAIR images was calculated using an automated volumetry pipeline (volBrain) and human processing. The age- and sex-adjusted MZ and DZ intra-pair correlations were determined and the total variance was decomposed into genetic, shared and unique environmental components using structural equation modeling. Results: Age and sex-adjusted MZ intrapair correlations were higher than DZ correlations, indicating moderate genetic influence in each lesion (rMZ = 0.466, rDZ = −0.025 for total count; rMZ = 0.482, rDZ = 0.093 for deep white matter count; rMZ = 0.739, rDZ = 0.39 for infratentorial count; rMZ = 0.573, rDZ = 0.372 for cerebellar count and rMZ = 0.473, rDZ = 0.19 for periventricular count), indicating a moderate heritability (A = 40.3%, A = 45%, A = 72.7% and A = 55.5%and 47.2%, respectively). The rest of the variance was influenced by unique environmental effects (E between 27.3% and 59.7%, respectively). Conclusions: The number of WMH lesions is moderately influenced by genetic effects, particularly in the infratentorial region in middle-aged twins. These results suggest that the distribution of WMH in various brain regions is heterogeneous.

Neurovascular coupling in patients with type 2 diabetes mellitus

Functional and metabolic neural changes in Type 2 diabetes mellitus (T2DM) can be associated with poor cognitive performances. Here we analyzed the functional-metabolic neurovascular coupling (NVC) in the brain of T2DM patients. Thirty-three patients (70 ± 6 years, 15 males) with recent T2DM diagnosis and 18 healthy control (HC) subjects (65 ± 9 years, 9 males) were enrolled in a brain MRI study to identify the potential effects of T2DM on NVC. T2DM patients were either drug-naive (n = 19) or under treatment with metformin (n = 14) since less than 6 months. Arterial spin labeling and blood oxygen level dependent resting-state functional MRI (RS-fMRI) images were combined to derive NVC measures in brain regions and large-scale networks in a standard brain parcelation. Altered NVC values in T2DM patients were correlated with cognitive performances spanning several neurological domains using Spearman correlation coefficients. Compared to HC, T2DM patients had reduced NVC in the default mode network (DMN) and increased NVC in three regions of the dorsal (DAN) and salience-ventral (SVAN) attention networks. NVC abnormalities in DAN and SVAN were associated with reduced visuo-spatial cognitive performances. A spatial pattern of NVC reduction in the DMN, accompanied by isolated regional NVC increases in DAN and SVAN, could reflect the emergence of (defective) compensatory processes in T2DM patients in response to altered neurovascular conditions. Overall, this pattern is reminiscent of neural abnormalities previously observed in Alzheimer’s disease, suggesting that similar neurobiological mechanisms, secondary to insulin resistance and manifesting as NVC alterations, might be developing in T2DM pathology.

Dose-response association between plasma homocysteine and white matter lesions in patients with hypertension: a case-control study

White matter lesions (WMLs) are common MRI changes that are indicative of cerebral small vessel disease (CSVD). Elevated plasma homocysteine (Hcy) levels are related to an increased risk of vascular disease. We aimed to analyze the relationship between Hcy levels and WMLs in patients with hypertension. A total of 1961 patients with WMLs and 15,463 patients without WMLs were matched at a 1:1 ratio by age and sex. Hyperhomocysteinemia (HHcy) was defined as an abnormally high level (>15 µmol/l) of Hcy in a plasma sample. In total, 1888 (WML group) and 1888 (No-WMLs group) patients were enrolled, with 51.6% of the sample being male and a mean age of 63 years. Multivariate logistic regression analysis showed a significant association between a higher level of plasma Hcy and a higher prevalence of WMLs (OR 1.03 95% CI, 1.02-1.04) when the Hcy level was used as a continuous variable. Patients with Hcy levels of 15-20 µmol/l (OR 1.54, 95% CI 1.31-1.81) and >20 µmol/l (OR 1.51, 95% CI 1.26-1.82) also had a significantly higher risk of WMLs than patients with Hcy levels <15 µmol/l. Multivariable-adjusted spline regression models showed that the risk of WMLs started to increase only in patients with Hcy levels above 13.85 µmol/l (P < 0.001). In subgroup analyses of WMLs, there was no significant interaction between the Hcy group and subgroup heterogeneity for the prevalence of WMLs (P > 0.05). Our study found a dose-response association between plasma homocysteine levels, especially a Hcy level >13.85 µmol/l, and the prevalence of WMLs, implying that lowering Hcy levels might be a target for prevention.

Gray and white matter abnormality in patients with T2DM-related cognitive dysfunction: a systemic review and meta-analysis

Aims/hypothesis

Brain structure abnormality in patients with type 2 diabetes mellitus (T2DM)-related cognitive dysfunction (T2DM-CD) has been reported for decades in magnetic resonance imaging (MRI) studies. However, the reliable results were still unclear. This study aimed to make a systemic review and meta-analysis to find the significant and consistent gray matter (GM) and white matter (WM) alterations in patients with T2DM-CD by comparing with the healthy controls (HCs).

Methods

Published studies were systemically searched from PubMed, MEDLINE, Cochrane Library and Web of Science databases updated to November 14, 2021. Studies reporting abnormal GM or WM between patients with T2DM-CD and HCs were selected, and their significant peak coordinates (x, y, z) and effect sizes (z-score or t-value) were extracted to perform a voxel-based meta-analysis by anisotropic effect size-signed differential mapping (AES-SDM) 5.15 software.

Results

Total 15 studies and 16 datasets (1550 participants) from 7531 results were involved in this study. Compared to HCs, patients with T2DM-CD showed significant and consistent decreased GM in right superior frontal gyrus, medial orbital (PFCventmed. R, BA 11), left superior temporal gyrus (STG. L, BA 48), and right calcarine fissure / surrounding cortex (CAL. R, BA 17), as well as decreased fractional anisotropy (FA) in right inferior network, inferior fronto-occipital fasciculus (IFOF. R), right inferior network, longitudinal fasciculus (ILF. R), and undefined area (32, −60, −42) of cerebellum. Meta-regression showed the positive relationship between decreased GM in PFCventmed.R and MoCA score, the positive relationship between decreased GM in STG.L and BMI, as well as the positive relationship between the decreased FA in IFOF.R and age or BMI.

Conclusions/interpretation

T2DM impairs the cognitive function by affecting the specific brain structures. GM atrophy in PFCventmed. R (BA 11), STG. L (BA 48), and CAL. R (BA 17), as well as WM injury in IFOF. R, ILF. R, and undefined area (32, −60, −42) of cerebellum. And those brain regions may be valuable targets for future researches. Age, BMI, and MoCA score have a potential influence on the altered GM or WM in T2DM-CD.

Relationships Among Perception of Cognitive Function, Diabetes Self-Management, and Glucose Variability in Older Adults: A Mixed Methods Study

The aim of the current study was to explore relationships among perceived cognitive function, glucose variability, and self-management in older adults with type 2 diabetes mellitus (T2DM). A mixed methods design was used with data from: (a) questionnaires on perceived cognitive function and diabetes self-management; (b) continuous glucose monitoring (CGM) reports; and (c) semi-structured interviews. Thirty adults with T2DM (47% female; mean age = 68.5 [SD = 5.2] years) participated. Those who exercised more days per week had more stable glucose. Those who reported fewer days of diet adherence had more hypoglycemia. Participants who reported higher levels of memory dissatisfaction exhibited higher levels of glucose variability. Findings point to the potential of glucose variability as a target to reduce the effect of diabetes on cognitive function. Instruction in recognition of glucose patterns found via CGM can be integrated into self-management education to improve self-management and subsequent glucose control and cognitive function. [Research in Gerontological Nursing, xx(x), xx-xx.].

Type 2 diabetes mellitus-associated cognitive dysfunction: Advances in potential mechanisms and therapies

Type 2 diabetes (T2D) and its target organ injuries cause distressing impacts on personal health and put an enormous burden on the healthcare system, and increasing attention has been paid to T2D-associated cognitive dysfunction (TDACD). TDACD is characterized by cognitive dysfunction, delayed executive ability, and impeded information-processing speed. Brain imaging data suggest that extensive brain regions are affected in patients with T2D. Based on current findings, a wide spectrum of non-specific neurodegenerative mechanisms that partially overlap with the mechanisms of neurodegenerative diseases is hypothesized to be associated with TDACD. However, it remains unclear whether TDACD is a consequence of T2D or a complication that co-occurs with T2D. Theoretically, anti-diabetes methods are promising neuromodulatory approaches to reduce brain injury in patients with T2D. In this review, we summarize potential mechanisms underlying TDACD and promising neurotropic effects of anti-diabetes methods and some neuroprotective natural compounds. Constructing screening or diagnostic tools and developing targeted treatment and preventive strategies would be expected to reduce the burden of TDACD.

Understanding the inter-relationships of type 2 diabetes and hypertension with brain and cognitive health: A UK Biobank study

AIM

To understand the impact of diabetes and co-morbid hypertension on cognitive and brain health.

MATERIALS AND METHODS

We used data from the UK Biobank cohort consisting of ~500 000 individuals aged 40 to 69 years. Our outcomes included brain structural magnetic resonance imaging variables and cognitive function tests in a maximum of 38 918 individuals. We firstly tested associations with all outcomes between those with diabetes (n = 2043) and without (n = 36 875) and, secondly, compared those with co-morbid diabetes/hypertension (n = 1283) with those with only diabetes (n = 760), hypertension (n = 9649) and neither disease (n = 27 226). Our analytical approach comprised linear regression models, with adjustment for a range of demographic and health factors. Standardized betas are reported.

RESULTS

Those with diabetes had worse brain and cognitive health for the majority of neuroimaging and cognitive measures, with the exception of g fractional anisotropy (white matter integrity), amygdala, pairs matching and tower rearranging. Compared with individuals with co-morbid diabetes and hypertension, those with only hypertension had better brain health overall, with the largest difference observed in the pallidum (β = .189, 95% CI = 0.241; 0.137), while those with only diabetes differed in total grey volume (β = .150, 95% CI = 0.122; 0.179). Individuals with only diabetes had better verbal and numeric reasoning (β = .129, 95% CI = 0.077; 0.261), whereas those with only hypertension performed better on the symbol-digit substitution task (β = .117, 95% CI = 0.048; 0.186).

CONCLUSIONS

Individuals with co-morbid diabetes and hypertension have worse brain and cognitive health compared with those with only one of these diseases. These findings potentially suggest that prevention of both diabetes and hypertension may delay changes in brain structure, as well as cognitive decline and dementia diagnosis.

Tractography in Type 2 Diabetes Mellitus With Subjective Memory Complaints: A Diffusion Tensor Imaging Study

The brain white matter (WM) structural injury caused by type 2 diabetes mellitus (T2DM) has been linked to cognitive impairment. However, the focus was mainly on the mild cognitive impairment (MCI) stage in most previous studies, with little attention made to subjective memory complaints (SMC). The main purpose of the current study was to investigate the characteristics of WM injury in T2DM patients and its correlation with SMC symptoms. In a group of 66 participants (33 HC and 33 T2DM-S), pointwise differences along WM tracts were identified using the automated fiber quantification (AFQ) approach. Then we investigated the utility of DTI properties along major WM tracts as features to distinguish patients with T2DM-S from HC via the support vector machine (SVM). Based on AFQ analysis, 10 primary fiber tracts that represent the subtle alterations of WM in T2DM-S were identified. Lower fractional anisotropy (FA) in the right SLF tract (r = −0.538, p = 0.0013), higher radial diffusivity (RD) in the thalamic radiation (TR) tract (r = 0.433, p = 0.012), and higher mean diffusivity (MD) in the right inferior fronto-occipital fasciculus (IFOF) tract (r = 0.385, p = 0.0029) were significantly associated with a long period of disease. Decreased axial diffusivity (AD) in the left arcuate was associated with HbA_1c (r = −0.368, p = 0.049). In addition, we found a significant negative correlation between delayed recall and abnormal MD in the left corticospinal tract (r = −0.546, p = 0.001). The FA of the right SLF tracts and bilateral arcuate can be used to differentiate the T2DM-S and the HC at a high accuracy up to 88.45 and 87.8%, respectively. In conclusion, WM microstructure injury in T2DM may be associated with SMC, and these abnormalities identified by DTI can be used as an effective biomarker.

A scoping review of resting-state brain functional alterations in Type 2 diabetes

Resting-state functional magnetic resonance imaging (rs-fMRI) has been actively used in the last decade to investigate brain functional connectivity alterations in Type 2 Diabetes Mellitus (T2DM) to understand the neuropathophysiology of T2DM in cognitive degeneration. Given the emergence of new analysis techniques, this scoping review aims to map the rs-fMRI analysis techniques that have been applied in the literature and reports the latest rs-fMRI findings that have not been covered in previous reviews. Graph theory, the contemporary rs-fMRI analysis, has been used to demonstrate altered brain topological organisations in people with T2DM, which included altered degree centrality, functional connectivity strength, the small-world architecture and network-based statistics. These alterations were correlated with T2DM patients' cognitive performances. Graph theory also contributes to identify unbiased seeds for seed-based analysis. The expanding rs-fMRI analytical approaches continue to provide new evidence that helps to understand the mechanisms of T2DM-related cognitive degeneration.

Association Between Use of Sodium-Glucose Co-Transporter-2 (SGLT2) Inhibitors and Cognitive Function in a Longitudinal Study of Patients with Type 2 Diabetes

BACKGROUND

The association between sodium-glucose cotransporter-2 inhibitors (SGLT2i) use and cognitive function in type 2 diabetes remains unclear.

OBJECTIVE

Explore the association between SGLT2i and longitudinal changes in cognitive function in adults with type 2 diabetes (T2DM) and assessed the cognitive domains which were impacted by SGLT2i.

METHODS

We conducted a prospective cohort study of 476 patients aged 60.6±7.4 years with follow-up period up to 6.4 years. Data on SGLT2i use was derived from questionnaire and verified with clinical database. We used Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to assess cognition. The association between SGLT2i use and rate of RBANS score change was examined using multiple linear regression.

RESULTS

There were 138 patients (29.0%) on SGLT2i, including 84 (17.7%) for <  3 years and 54 (11.3%) for ≥3 years. SGLT2i use was positively associated with RBANS total score increase in language (coefficient 0.60; 95% CI 0.10-1.11; p = 0.019) in unadjusted analysis. This positive association persisted in fully adjusted model (coefficient 0.74; 95% CI 0.12 to 1.36; p = 0.019). SGLT2i use for ≥3 years was positively associated with RBANS score increase globally and in language domain in fully adjusted analysis with coefficients 0.54 (95% CI 0.13 to 0.95; p = 0.010) and 1.12 (95% CI 0.27 to 1.97; p = 0.010) respectively.

CONCLUSION

Our findings revealed a previously unobserved association between ≥3 years SGLT2i use and improved cognitive scores globally and in language domain and executive function. Future studies should investigate the role of SGLT2i in ameliorating cognitive decline.

Diabetes and Ischemic Stroke: An Old and New Relationship an Overview of the Close Interaction between These Diseases

Diabetes mellitus is a comprehensive expression to identify a condition of chronic hyperglycemia whose causes derive from different metabolic disorders characterized by altered insulin secretion or faulty insulin effect on its targets or often both mechanisms. Diabetes and atherosclerosis are, from the point of view of cardio- and cerebrovascular risk, two complementary diseases. Beyond shared aspects such as inflammation and oxidative stress, there are multiple molecular mechanisms by which they feed off each other: chronic hyperglycemia and advanced glycosylation end-products (AGE) promote ‘accelerated atherosclerosis’ through the induction of endothelial damage and cellular dysfunction. These diseases impact the vascular system and, therefore, the risk of developing cardio- and cerebrovascular events is now evident, but the observation of this significant correlation has its roots in past decades. Cerebrovascular complications make diabetic patients 2–6 times more susceptible to a stroke event and this risk is magnified in younger individuals and in patients with hypertension and complications in other vascular beds. In addition, when patients with diabetes and hyperglycemia experience an acute ischemic stroke, they are more likely to die or be severely disabled and less likely to benefit from the one FDA-approved therapy, intravenous tissue plasminogen activator. Experimental stroke models have revealed that chronic hyperglycemia leads to deficits in cerebrovascular structure and function that may explain some of the clinical observations. Increased edema, neovascularization, and protease expression as well as altered vascular reactivity and tone may be involved and point to potential therapeutic targets. Further study is needed to fully understand this complex disease state and the breadth of its manifestation in the cerebrovasculature.

Relationship of fasting glucose and longitudinal Alzheimer's disease imaging markers

INTRODUCTION

Fasting glucose increases with age and is linked to modifiable Alzheimer's disease risk factors such as cardiovascular disease and Type 2 diabetes (T2D).

METHODS

We leveraged available biospecimens and neuroimaging measures collected during the Alzheimer's Prevention Through Exercise (APEx) trial (n = 105) to examine the longitudinal relationship between change in blood glucose metabolism and change in regional cerebral amyloid deposition and gray and white matter (WM) neurodegeneration in older adults over 1 year of follow-up.

RESULTS

Individuals with improving fasting glucose (n = 61) exhibited less atrophy and regional amyloid accumulation compared to those whose fasting glucose worsened over 1 year (n = 44). Specifically, while individuals with increasing fasting glucose did not yet show cognitive decline, they did have regional atrophy in the hippocampus and inferior parietal cortex, and increased amyloid accumulation in the precuneus cortex. Signs of early dementia pathology occurred in the absence of significant group differences in insulin or body composition, and was not modified by apolipoprotein E ε4 carrier status.

DISCUSSION

Dysregulation of glucose in late life may signal preclinical brain change prior to clinically relevant cognitive decline. Additional work is needed to determine whether treatments specifically targeting fasting glucose levels may impact change in brain structure or cerebral amyloid in older adults.

Role of diabetes in stroke: Recent advances in pathophysiology and clinical management

The increasing prevalence of diabetes and stroke is a major global public health concern. Specifically, acute stroke patients, with pre-existing diabetes, pose a clinical challenge. It is established that diabetes is associated with a worse prognosis after acute stroke and the various biological factors that mediate poor recovery profiles in diabetic patients is unknown. The level of association and impact of diabetes, in the setting of reperfusion therapy, is yet to be determined. This article presents a comprehensive overview of the current knowledge of the role of diabetes in stroke, therapeutic strategies for primary and secondary prevention of cardiovascular disease and/or stroke in diabetes, and various therapeutic considerations that may apply during pre-stroke, acute, sub-acute and post-stroke stages. The early diagnosis of diabetes as a comorbidity for stroke, as well as tailored post-stroke management of diabetes, is pivotal to our efforts to limit the burden. Increasing awareness and involvement of neurologists in the management of diabetes and other cardiovascular risk factors is desirable towards improving stroke prevention and efficacy of reperfusion therapy in acute stroke patients with diabetes.

Different cardiovascular risk factors are related to distinct white matter hyperintensity MRI phenotypes in older adults

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White matter hyperintensity (WMH) shape: a novel, advanced MRI marker.

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Hypertension correlates with a more irregular shape of periventricular/confluent WMH.

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Different cardiovascular/pathological mechanisms lead to distinct WMH MRI phenotypes.

The underlying mechanisms of the association between cardiovascular risk factors and a higher white matter hyperintensity (WMH) burden are unknown. We investigated the association between cardiovascular risk factors and advanced WMH markers in 155 non-demented older adults (mean age: 71 ± 5 years). The association between cardiovascular risk factors and quantitative MRI-based WMH shape and volume markers were examined using linear regression analysis. Presence of hypertension was associated with a more irregular shape of periventricular/confluent WMH (convexity (B (95 % CI)): −0.12 (−0.22–−0.03); concavity index: 0.06 (0.02–0.11)), but not with total WMH volume (0.22 (−0.15–0.59)). Presence of diabetes was associated with deep WMH volume (0.89 (0.15–1.63)). Body mass index or hyperlipidemia showed no association with WMH markers. In conclusion, different cardiovascular risk factors seem to be related to a distinct pattern of WMH shape markers in non-demented older adults. These findings may suggest that different underlying cardiovascular pathological mechanisms lead to different WMH MRI phenotypes, which may be valuable for early detection of individuals at risk for stroke and dementia.

Factors associated with brain white matter damage in type 2 diabetes mellitus: a tract-based spatial statistics study

BACKGROUND

The pathogenesis and related factors of central nervous system abnormality in patients with type 2 diabetes mellitus (T2DM) have always been the focus of clinical research.

PURPOSE

To compare and analyze the area of white matter (WM) damage in patients with T2DM based on their level of hemoglobin A_1C (HBA_1c) and discuss any related factors.

MATERIAL AND METHODS

Based on their levels of HBA_1c, 87 patients with T2DM were divided into three groups (Group B, C, or D), of which 29 non-diabetic volunteers served as the control group (Group A). DTI data analysis was based on tract-based spatial statistics (TBSS). The obtained parameters were compared among each group and the relevant clinical factors were analyzed.

RESULTS

For age, sex, mini-mental state examination (MMSE), and Montreal Cognitive Assessment (MoCA) scores, there were no statistically significant differences among groups. For fractional anisotropy (FA) and radial diffusivity (RD) of WM, there were statistically significant differences (P < 0.05, two-tailed, FWE corrected) in the local area of corpus callosum, corona radiate, superior longitudinal fasciculus, etc. Most of these were significantly correlated with body mass index (BMI), left systolic blood pressure (SBP_L), and β₂ microglobulin.

CONCLUSION

Before the cognitive function was obviously impaired, abnormalities of FA and RD had been found in the corpus callosum, corona radiate, and upper fasciculus in patients with T2DM, which suggested that the damage mainly occurred in the myelin sheath of WM and may be related to systemic vascular damage.

A Comprehensive Review of Neuronal Changes in Diabetics

There has been an exponential rise in diabetes mellitus (DM) cases on a global scale. Diabetes affects almost every system of the body, and the nervous system is no exception. Although the brain is dependent on glucose, providing it with the energy required for optimal functionality, glucose also plays a key role in the regulation of oxidative stress, cell death, among others, which furthermore contribute to the pathophysiology of neurological disorders. The variety of biochemical processes engaged in this process is only matched by the multitude of clinical consequences resulting from it. The wide-ranging effects on the central and peripheral nervous system include, but are not limited to axonopathies, neurodegenerative diseases, neurovascular diseases, and general cognitive impairment. All language search was conducted on MEDLINE, COCHRANE, EMBASE, and GOOGLE SCHOLAR till September 2021. The following search strings and Medical Subject Headings (MeSH terms) were used: "Diabetes Mellitus," "CNS," "Diabetic Neuropathy," and "Insulin." We explored the literature on diabetic neuropathy, covering its epidemiology, pathophysiology with the respective molecular pathways, clinical consequences with a special focus on the central nervous system and finally, measures to prevent and treat neuronal changes. Diabetes is slowly becoming an epidemic, rapidly increasing the clinical burden on account of its wide-ranging complications. This review focuses on the neuronal changes occurring in diabetes such as the impact of hyperglycemia on brain function and structure, its association with various neurological disorders, and a few diabetes-induced peripheral neuropathic changes. It is an attempt to summarize the relevant literature about neuronal consequences of DM as treatment options available today are mostly focused on achieving better glycemic control; further research on novel treatment options to prevent or delay the progression of neuronal changes is still needed.

Cardiovascular co-morbidities, inflammation and cerebral small vessel disease

Cerebral small vessel disease (cSVD) is the most common cause of vascular cognitive impairment and affects all levels of the brain's vasculature. Features include diverse structural and functional changes affecting small arteries and capillaries that lead to a decline in cerebral perfusion. Due to an aging population, incidence of cerebral small vessel disease (cSVD) is continually rising. Despite its prevalence and its ability to cause multiple debilitating illnesses, such as stroke and dementia, there are currently no therapeutic strategies for the treatment of cSVD. In the healthy brain, interactions between neuronal, vascular and inflammatory cells are required for normal functioning. When these interactions are disturbed, chronic pathological inflammation can ensue. The interplay between cSVD and inflammation has attracted much recent interest and this review discusses chronic cardiovascular diseases, particularly hypertension, and explores how the associated inflammation may impact on the structure and function of the small arteries of the brain in cSVD. Molecular approaches in animal studies are linked to clinical outcomes in patients and novel hypotheses regarding inflammation and cSVD are proposed that will hopefully stimulate further discussion and study in this important area.

White Matter Microstructural Damage Associated With Gait Abnormalities in Idiopathic Normal Pressure Hydrocephalus

Background: Idiopathic normal pressure hydrocephalus (iNPH) is a common disease in elderly adults. Patients with iNPH are generally characterized by progressive gait impairment, cognitive deficits, and urinary urgency and/or incontinence. A number of radiographic studies have shown that iNPH patients have enlarged ventricles and altered brain morphology; however, few studies have focused on the relationships between altered brain structure and gait dysfunction due to iNPH. Thus, this study aimed to evaluate the abnormalities of white matter (WM) correlated with gait impairment in iNPH patients and to gain a better understanding of its underlying pathology.

Methods: Fifteen iNPH patients (five women, 10 men) were enrolled in this study, and each patient’s demographic and gait indices were collected. First, we performed a correlation analysis between the demographic and gait indices. Then, all gait indices were grouped according to the number of WM hyperintensities (WMH) among each WM tract (JHU WM tractography atlas), to perform comparative analysis.

Results: Considering sex and illness duration as covariates, correlation analysis showed a significantly negative correlation between step length (r = −0.80, p = 0.001), pace (r = −0.84, p = 2.96e-4), and age. After removing the effects of age, sex, and illness duration, correlation analysis showed negative correlation between step length (r = −0.73, p = 0.007), pace (r = −0.74, p = 0.005), and clinical-grade score and positive correlation between 3-m round trip time (r = 0.66, p = 0.021), rising time (r = 0.76, p = 0.004), and clinical-grade score. Based on WMH of each white matter tract, gait indices showed significant differences (p < 0.05/48, corrected by Bonferroni) between fewer WMH patients and more WMH in the middle cerebellar peduncle, left medial lemniscus, left posterior limb of the internal capsule (IC), and right posterior limb of the IC.

Conclusions: Our results indicated that iNPH patients exhibited gait-related WM abnormalities located in motor and sensory pathways around the ventricle, which is beneficial to understand the underlying pathology of iNPH.

ESO Guideline on covert cerebral small vessel disease

'Covert' cerebral small vessel disease (ccSVD) is common on neuroimaging in persons without overt neurological manifestations, and increases the risk of future stroke, cognitive impairment, dependency, and death. These European Stroke Organisation (ESO) guidelines provide evidence-based recommendations to assist with clinical decisions about management of ccSVD, specifically white matter hyperintensities and lacunes, to prevent adverse clinical outcomes. The guidelines were developed according to ESO standard operating procedures and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. We prioritised the clinical outcomes of stroke, cognitive decline or dementia, dependency, death, mobility and mood disorders, and interventions of blood pressure lowering, antiplatelet drugs, lipid lowering, lifestyle modifications, glucose lowering and conventional treatments for dementia. We systematically reviewed the literature, assessed the evidence, formulated evidence-based recommendations where feasible, and expert consensus statements. We found little direct evidence, mostly of low quality. We recommend patients with ccSVD and hypertension to have their blood pressure well controlled; lower blood pressure targets may reduce ccSVD progression. We do not recommend antiplatelet drugs such as aspirin in ccSVD. We found little evidence on lipid lowering in ccSVD. Smoking cessation is a health priority. We recommend regular exercise which may benefit cognition, and a healthy diet, good sleep habits, avoiding obesity and stress for general health reasons. In ccSVD, we found no evidence for glucose control in the absence of diabetes or for conventional Alzheimer dementia treatments. Randomised controlled trials with clinical endpoints are a priority for ccSVD.