Hyperglycaemia, microangiopathy, diabetes and dementia risk

Dermal features derived from optoacoustic tomograms via machine learning correlate microangiopathy phenotypes with diabetes stage

Skin microangiopathy has been associated with diabetes. Here we show that skin-microangiopathy phenotypes in humans can be correlated with diabetes stage via morphophysiological cutaneous features extracted from raster-scan optoacoustic mesoscopy (RSOM) images of skin on the leg. We obtained 199 RSOM images from 115 participants (40 healthy and 75 with diabetes), and used machine learning to segment skin layers and microvasculature to identify clinically explainable features pertaining to different depths and scales of detail that provided the highest predictive power. Features in the dermal layer at the scale of detail of 0.1-1 mm (such as the number of junction-to-junction branches) were highly sensitive to diabetes stage. A 'microangiopathy score' compiling the 32 most-relevant features predicted the presence of diabetes with an area under the receiver operating characteristic curve of 0.84. The analysis of morphophysiological cutaneous features via RSOM may allow for the discovery of diabetes biomarkers in the skin and for the monitoring of diabetes status.

The silent occurrence of cerebral small vessel disease in nonelderly patients with type 2 diabetes mellitus

BACKGROUND

The prevalence of cerebral small vessel disease (SVD) increases in elderly patients with type 2 diabetes (T2DM), exacerbating cognitive decline. However, the prevalence and the severity of SVD in dementia-free nonelderly T2DM patients were largely unknown. Our primary aim is to investigate SVD in such patients, with a specific focus on the correlation between SVD and diabetic peripheral sensorimotor polyneuropathy (DSP).

METHODS

We recruited 180 young and middle-aged subjects without cognitive impairment (106 with T2DM, 74 controls). Signs of cerebral SVD on magnetic resonance image were investigated, and the overall SVD burden was evaluated by a combined score. Patients with T2DM underwent further detailed DSP assessment. Regression models were used to investigate the association of SVD with the presence of T2DM, and the associations of the prevalence and severity of SVD and DSP were also explored in patients with T2DM.

RESULTS

The prevalence of microbleeds and overall burden of SVD were significantly higher in T2DM patients than in the controls. Further, the presence of DSP related to an increased risk of SVD after adjustment in diabetic group. Moreover, Toronto Clinical Scoring System values were positively associated with the increased SVD scores, and bilateral sural sensory nerve conduction velocities were negatively associated with increasingly severity of SVD scores.

CONCLUSION

The current findings extended the increasing prevalence of SVD to dementia-free nonelderly patients with T2DM, suggesting that the time for cognitive screening and prevention might be moved forward in T2DM patients, especially for those with DSP.

Gait Speed and Evolution of Verbal Fluencies in Frail or Prefrail Older People with Type 2 Diabetes. A Pilot Study

OBJECTIVES

Type 2 diabetes (T2D) is a risk factor of frailty and cognitive impairment. Impaired gait in older people is associated with incident vascular dementia. We aimed to assess whether in frail or prefrail older subjects with T2D, lower gait speed can be associated with faster cognitive decline.

DESIGN

Case-control study nested in a large randomized control trial (RCT, MID-frail); post hoc analysis.

SETTING AND PARTICIPANTS

Older frail and prefrail subjects (>70y) with T2D and with no history of cognitive problems were enrolled in a single recruiting center. Participants were divided into two groups depending on their walking speed - above (fast walkers) or below (slow walkers) using a cut off of 1 m/sec.

MEASURE

Cognitive function was assessed at baseline and during follow-up with the MMSE, category and letter fluencies at 15 sec (initiation) and 15-60 sec (late).

RESULTS

48 subjects were included, 22 were fast walkers, 26 were slow walkers. The mean follow-up was 60.9 (SD 17.5) weeks. The baseline 0-15 sec letter fluency was higher in fast walkers (p=0.008). There was no difference at baseline with MMSE scores and category fluency. The MID-Frail intervention did not change the evolution of any cognitive changes. Comparisons were adjusted for age, sex and baseline performance, and showed a steeper decline of category fluency score in slow walkers (fast walkers +0.04 (-1.49 to1.56) compared with -0.89 (-2.15 to 0.38), p=0.049) with a moderate effect size.

CONCLUSION

In frail or prefrail older adults with diabetes, we observed a decline in category fluency in those with low gait speed.

Frailty and Brain-Muscle Correlates in Older People With Type 2 Diabetes: A structural-MRI Explorative Study

OBJECTIVES

Muscle alterations, mainly functional alterations are frequently observed in older people with type 2 diabetes (T2DM). Sarcopenia may be one mechanism of transition to frailty in these people. Thus, we aim to explore the characteristics of muscle and its association with cerebral grey matter volumes within this group.

METHODS

Single center study nested within the international MID-Frail (a randomized clinical trial to evaluate the effectiveness of a multi-modal intervention in older people with T2DM on frailty and quality of life) trial participants underwent both brain and muscle T1 MRI, nutritional and functional assessments. Muscle areas were measured in rectus femoris (RF). Relationships between MRI grey matter volumes and muscle areas or function tests were described using positive and negative regressions.

RESULTS

Twenty-six subjects (7 female, mean age 78.2 y, SD 5.0), 6 frail and 20 pre-frail were explored in this sub-study. Frail subjects had lower Mini Nutritional Assessment (MNA), Short Physical Performance Battery (SPPB), hip flexor strength than pre-frail ones but similar BMI and balance. Total SPPB was positively related with hip flexor strength and maximal RF area. Balance SPPB sub-score was unrelated to strength or RF area. MNA score was correlated with hip flexor strength and to global grey matter but not to SPPB. Hip flexor strength was correlated with grey matter areas involved in motor control. Walking time was negatively and rising chair sub-score was positively associated with grey matter volumes of motor areas.

CONCLUSIONS

Sarcopenia features were more frequent in frail than prefrail subjects and were associated with decrease in grey matter volumes involved in motor control.

Population-based Study of Risk Polymorphisms Associated with Vascular Disorders and Dementia

Introduction:

Cardiovascular and neurodegenerative disorders are among the major causes of mortality in the developed countries. Population studies evaluate the genetic risk, i.e. the probability of an individual carrying a specific disease-associated polymorphism. Identification of risk polymorphisms is essential for an accurate diagnosis or prognosis of a number of pathologies.

Aims:

The aim of this study was to characterize the influence of risk polymorphisms associated with lipid metabolism, hypertension, thrombosis, and dementia, in a large population of Spanish individuals affected by a variety of brain and vascular disorders as well as metabolic syndrome.

Material & Method:

We performed a cross-sectional study on 4415 individuals from a widespread regional distribution in Spain (48.15% males and 51.85% females), with mental, neurodegenerative, cerebrovascular, and metabolic disorders. We evaluated polymorphisms in 20 genes involved in obesity, vascular and cardiovascular risk, and dementia in our population and compared it with representative Spanish and European populations. Risk polymorphisms in ACE, AGT(235), IL6(573), PSEN1, and APOE (specially the APOE-ε4 allele) are representative of our population as compared to the reference data of Spanish and European individuals.

Conclusion:

The significantly higher distribution of risk polymorphisms in PSEN1 and APOE-ε4 is characteristic of a representative number of patients with Alzheimer’s disease; whereas polymorphisms in ACE, AGT(235), and IL6(573), are most probably related with the high number of patients with metabolic syndrome or cerebrovascular damage.

Inflammation as a neurobiological substrate of cognitive impairment in bipolar disorder: Evidence, pathophysiology and treatment implications

BACKGROUND

Bipolar disorder (BD) has been associated with cognitive impairment during depressed, manic and euthymic periods. Inflammation has been shown to be involved in the pathophysiology of BD and cognitive impairment.

METHODS

For this systematic review, the MEDLINE/PubMed, Embase, Google Scholar and ClinicalTrials.gov databases were searched for relevant articles assessing the association between cognitive function and inflammatory markers in BD subjects. A discussion of potential mechanisms and therapeutic implications is also included to provide further context to the subject matter.

RESULTS

Eight studies, including a total of 555 BD subjects, assessing the association between cognitive function and inflammatory markers were identified. Cognitive dysfunction was associated with elevated levels of pro-inflammatory markers YKL40, IL-6, sCD40L, IL-1Ra, hsCRP and TNF-α. Mechanistically, elevation in inflammatory cytokines alters monoamine levels leading to cognitive and affective dysfunction. Neuro-inflammation, manifesting as microglial activation, leads to increased oxidative stress, pathologic synaptic pruning and impaired neuroplasticity in key brain regions sub-serving mood and cognition. Immune dysfunction also activates the hypothalamic-pituitary-adrenal (HPA) axis leading to hypercortisolemia and metabolic dysfunction, further promoting neuronal dysfunction. Anti-inflammatory agents are therefore currently being investigated in the treatment of BD and appear to exert an antidepressant effect; however, cognitive outcomes have yet to be reported.

CONCLUSION

Several studies suggest that immune dysfunction is associated with cognitive impairment in BD. Several neurobiological pathways have been identified whereby immune dysfunction may promote cognitive impairment in BD. Future investigations of anti-inflammatory agents targeting cognitive function as a treatment outcome are merited.

Diabetes mellitus and disturbances in brain connectivity: a bidirectional relationship?

Diabetes mellitus (DM) is associated with deficits across multiple cognitive domains. The observed impairments in cognitive function are hypothesized to be subserved by alterations in brain structure and function. Several lines of evidence indicate that alterations in glial integrity and function, as well as abnormal synchrony within brain circuits and associated networks, are observed in adults with DM. Microangiopathy and alterations in insulin homeostasis appear to be principal effector systems, although a unitary explanation subsuming the complex etiopathology of white matter in DM is unavailable. A contemporary model of disease pathophysiology for several mental disorders, including but not limited to mood disorders, posits abnormalities in the synchronization of cellular systems in circuits. The observation that similar abnormalities occur in diabetic populations provides the basis for hypothesizing the convergence of pathoetiological factors. Herein, we propose that abnormal structure, function and chemical composition as well as synchrony within and between circuits is an accompaniment of DM and is shared in common with several mental disorders.

Relationship between blood pressure, cognitive function and education level in elderly patients with diabetes: a preliminary study

AIMS

This study aimed to assess the relationship between blood pressure and cognitive function in elderly patients with diabetes mellitus (DM).

METHODS

A total of 32 patients with DM aged ≥ 65 years (seven women and 25 men; mean ± SD age: 74.3 ± 6.4 years) were included in this cross-sectional study. Relationships between blood pressure and neuropsychological tests were determined using Spearman's rank correlations (ρ) and multivariable linear regression models.

RESULTS

Lower diastolic blood pressure was associated with lower scores on the Frontal Assessment Battery (ρ=0.32, P=0.02), longer times to complete the Trail Making Test Part B (ρ=0.51, P=0.003), lower scores for the Finger Tapping Test (ρ=0.36, P=0.046) and less verbal fluency (ρ=0.36, P=0.047). In multivariable models, these relationships were attenuated after adjusting for levels of education.

CONCLUSION

There was an association between lower diastolic blood pressure and poorer executive function in this cohort of elderly DM patients. These results underline the importance of systematic cognitive evaluation in elderly patients with DM, and suggest that a too-low diastolic blood pressure may have deleterious effects on mental function. Larger studies in the future are required to confirm these preliminary results.

Disability in older people with diabetes: issues for the clinician

Diabetes may become a disabling disease due to diverse mechanisms. Many patients have evidence of physical or cognitive impairments that can markedly influence their ability to diabetes self manage and adversely affect possible outcomes of diabetes care. A screening process for impairment is therefore needed and in frail patients a comprehensive gerontological assessment should be used to improve the efficiency of care. A diabetes educational programme adapted to this population, which has involved the main care-giver has shown its efficacy to improve risk factor control and quality of life in a safer way. The experience of case-managers according to a model of heart failure may be promising for the future.