Cognitive impairment in diabetes and poor glucose utilization in the intracellular neural milieu

The prevalence and characteristics of alexithymia in stroke patients: a systematic review and meta-analysis

BACKGROUND

Previous studies have indicated the potential occurrence of alexithymia among stroke patients, yet the prevalence of alexithymia in this population remains disparate across different investigations without a synthesized overview.

AIM

To systematically evaluate the prevalence and characteristics of alexithymia in stroke patients.

METHODS

A systematic review and meta-analysis was conducted following the PRISMA guidelines. PubMed, Embase, Web of Science, The Cochrane Library, CINAHL, China Knowledge Resource Integrated Database (CNKI), Wanfang Database, Chinese Biomedical Database, and Weipu Database (VIP) were searched from inception to December 31,2022, two independent researchers extracted data and evaluated article quality.

RESULTS

Seventeen studies were included, reporting on the prevalence of alexithymia or Toronto Alexithymia Scale-20 (TAS-20) scores among stroke patients. The pooled prevalence was found to be 35.0% (95%CI= 23.0-47.0%; I2 =97.5%), and the total scores (TS) of TAS-20 was 59.90 (95% CI=56.34-63.47; I2 =100.0%). Subgroup analysis revealed significant variation in TAS-20 scores across different geographical regions. Specifically, the total TAS-20 score in Chinese stroke patients (62.95, 95%CI=58.75-67.14; I2=100%) was higher compared to non-Chinese stroke patients (52.58, 95%CI=49.12-56.04; I2 = 99.0%).

CONCLUSIONS

The prevalence of alexithymia is high among stroke patients, with TAS-20 scores surpassing those observed in patients with certain other medical conditions. This underscores the importance of addressing alexithymia in stroke patients promptly through assessment and intervention to mitigate negative emotional consequences and enhance overall quality of life. Future research could explore the influence of demographic factors such as age and sex on alexithymia in stroke patients, enabling a more comprehensive understanding of alexithymia.

The gut microbiota-astrocyte axis: Implications for type 2 diabetic cognitive dysfunction

BACKGROUND

Diabetic cognitive dysfunction (DCD) is one of the most insidious complications of type 2 diabetes mellitus, which can seriously affect the ability to self-monitoring of blood glucose and the quality of life in the elderly. Previous pathological studies of cognitive dysfunction have focused on neuronal dysfunction, characterized by extracellular beta-amyloid deposition and intracellular tau hyperphosphorylation. In recent years, astrocytes have been recognized as a potential therapeutic target for cognitive dysfunction and important participants in the central control of metabolism. The disorder of gut microbiota and their metabolites have been linked to a series of metabolic diseases such as diabetes mellitus. The imbalance of intestinal flora has the effect of promoting the occurrence and deterioration of several diabetes-related complications. Gut microbes and their metabolites can drive astrocyte activation.

AIMS

We reviewed the pathological progress of DCD related to the "gut microbiota-astrocyte" axis in terms of peripheral and central inflammation, intestinal and blood-brain barrier (BBB) dysfunction, systemic and brain energy metabolism disorders to deepen the pathological research progress of DCD and explore the potential therapeutic targets.

CONCLUSION

"Gut microbiota-astrocyte" axis, unique bidirectional crosstalk in the brain-gut axis, mediates the intermediate pathological process of neurocognitive dysfunction secondary to metabolic disorders in diabetes mellitus.

Insulin and fluoxetine produce opposite actions on lateral septal nucleus-infralimbic region connection responsivity

Some diabetes patients develop depression, the main treatment for which is antidepressants. Pharmacological interactions between insulin and antidepressants (e.g., fluoxetine) are controversial in the literature. Some authors reported hypoglycemic actions of fluoxetine, whereas others reported antidepressant-like actions. In healthy rats, insulin produces an antidespair-like action in rats through an increase in locomotor and exploratory activity, but differences in actions of insulin and fluoxetine on neuronal activity are unknown. The present study evaluated Wistar healthy rats that were treated with saline, insulin, fluoxetine, or fluoxetine + insulin for 3 days (short-term) or 21 days (long-term). The model consisted of electrical stimulation of the lateral septal nucleus (LSN) while we performed single-unit extracellular response recordings in the prelimbic cortex (PL) and infralimbic cortex (IL) subregions of the medial prefrontal cortex (mPFC). Stimulation of the LSN produced an initial brief excitatory paucisynaptic response and then a long-lasting inhibitory afterdischarge in the PL and IL. Treatment with saline and fluoxetine, but not insulin, minimally affected the paucisynaptic response. Differences were found in LSN-IL responsivity. The inhibitory afterdischarge was clearly enhanced in the long-term fluoxetine group but not by insulin alone or fluoxetine + insulin. These findings suggest that insulin produces some actions that are opposite to fluoxetine on LSN-mPFC connection responsivity, with no synergistic actions between the actions of insulin and fluoxetine.

The prevalence and characteristics of alexithymia in patients with type 2 diabetes mellitus: A systematic review and meta-analysis

BACKGROUND

Alexithymia is common in patients with type 2 diabetes mellitus (T2DM). Although the estimated prevalence of alexithymia in patients with T2DM is widely reported, these results have not been synthesized.

AIM

To systematically assess the prevalence and characteristics of alexithymia in patients with T2DM.

METHODS

We searched for relevant publications in PubMed, Embase, Web of Science, China Knowledge Resource Integrated Database, Wanfang Database, Chinese Biomedical Database, and Weipu Database. The prevalence of alexithymia, the mean scores, and standard deviations of the total scale of the 20-item Toronto Alexithymia Scale (TAS-20) were pooled using random effects meta-analysis in Stata 13.0, with studies stratified by study location in this meta-analysis.

RESULTS

This meta-analysis included thirteen articles. Pooled prevalence of alexithymia (TAS-20 total scores ≥61) were 43.0% (95%CI 35.0-51.0%), and the prevalence of alexithymia was higher in China (45.0%, 95%CI 36.0-54.0%) compared with non-China (41.0%, 95%CI 29.0-54.0%). The pooled mean score for the TAS-20 total scale was 57.70 (95% CI 55.25-60.15). Leave-one-out analysis showed that none of the studies significantly impacted the overall pooled results.

CONCLUSIONS

This meta-analysis indicated a high prevalence of alexithymia in patients with T2DM. Thus, clinicians need to be aware of and assess appropriately for alexithymia in patients with T2DM.

Brain Energy Metabolism in Ischemic Stroke: Effects of Smoking and Diabetes

Proper regulation of energy metabolism in the brain is crucial for maintaining brain activity in physiological and different pathophysiological conditions. Ischemic stroke has a complex pathophysiology which includes perturbations in the brain energy metabolism processes which can contribute to worsening of brain injury and stroke outcome. Smoking and diabetes are common risk factors and comorbid conditions for ischemic stroke which have also been associated with disruptions in brain energy metabolism. Simultaneous presence of these conditions may further alter energy metabolism in the brain leading to a poor clinical prognosis after an ischemic stroke event. In this review, we discuss the possible effects of smoking and/or diabetes on brain glucose utilization and mitochondrial energy metabolism which, when present concurrently, may exacerbate energy metabolism in the ischemic brain. More research is needed to investigate brain glucose utilization and mitochondrial oxidative metabolism in ischemic stroke in the presence of smoking and/or diabetes, which would provide further insights on the pathophysiology of these comorbid conditions and facilitate the development of therapeutic interventions.

Putative Anti-Immobility Action of Acute Insulin Is Attributable to an Increase in Locomotor Activity in Healthy Wistar Rats

BACKGROUND/AIMS

Anti-immobility actions of insulin in diabetic rats that are subjected to the forced swim test (FST) have been reported. In this test, low doses of antidepressants exert actions after long-term treatment, without affecting locomotor activity in healthy rats. Few studies have compared acute and chronic actions of insulin with antidepressants in healthy rats.

METHODS

We hypothesized that if insulin exerts a true anti-immobility action, then its effects must be comparable to fluoxetine in both a 1-day treatment regimen and a 21-day treatment regimen in healthy, gonadally intact female Wistar rats.

RESULTS

The results showed that low levels of glycemia were produced by all treatments, including fluoxetine, and glycemia was lower in proestrus-estrus than in diestrus-metestrus. None of the treatments or regimens produced actions on indicators of anxiety in the elevated plus maze. Insulin in the 1-day regimen increased the number of crossings and rearings in the open field test and caused a low cumulative immobility time in the FST. These actions disappeared in the 21-day regimen. Compared with the other treatments, fluoxetine treatment alone or combined with insulin produced a longer latency to the first period of immobility and a shorter immobility time in the chronic regimen in the FST, without affecting locomotor activity, and more pronounced actions were observed in proestrus-estrus (i.e., a true anti-immobility effect).

CONCLUSION

These results indicate that insulin does not produce a true antidepressant action in healthy rats. The purported antidepressant effects that were observed were instead attributable to an increase in locomotor activity only in the 1-day regimen.

Modulation of Glucose Availability and Effects of Hypo- and Hyperglycemia on Status Epilepticus: What We Do Not Know Yet?

Status epilepticus (SE) can lead to serious neuronal damage and act as an initial trigger for epileptogenic processes that may lead to temporal lobe epilepsy (TLE). Besides promoting neurodegeneration, neuroinflammation, and abnormal neurogenesis, SE can generate an extensive hypometabolism in several brain areas and, consequently, reduce intracellular energy supply, such as adenosine triphosphate (ATP) molecules. Although some antiepileptic drugs show efficiency to terminate or reduce epileptic seizures, approximately 30% of TLE patients are refractory to regular antiepileptic drugs (AEDs). Modulation of glucose availability may provide a novel and robust alternative for treating seizures and neuronal damage that occurs during epileptogenesis; however, more detailed information remains unknown, especially under hypo- and hyperglycemic conditions. Here, we review several pathways of glucose metabolism activated during and after SE, as well as the effects of hypo- and hyperglycemia in the generation of self-sustained limbic seizures. Furthermore, this study suggests the control of glucose availability as a potential therapeutic tool for SE.

The Relationship Between Alexithymia and Type 2 Diabetes: A Systematic Review

Background: This systematic review analyzed the relationship between alexithymia, considered as the inability to recognize and express thoughts and emotions, and type 2 diabetes mellitus (T2DM), one of the most common chronic illness, characterized by a metabolic disorder burdened by high morbidity and mortality worldwide due to its outcomes. Methods: PRISMA guidelines were followed throughout this systematic review of the recent literature indexed in the databases PubMed, PsycInfo, Scopus, and Web of Science. Search terms for eligible studies were: "Type 2 diabetes" OR "T2DM" AND "Toronto Alexithymia Scale" OR "TAS-20"[All Fields]. Results: The initial search identified 61 indexed scientific publications. After screening we found that seven publications met the established scientific inclusion and exclusion criteria. It emerged that alexithymic patients ranged from 25 to 50% across the examined publications and it appeared that patients with T2DM generally reflected greater values of alexithymia, revealing particular differences among TAS domains. Moreover, emlpoyed participants were alexithymic to a greater extent compared to non-working participants (77.8 vs. 35.4%) and alexithymia was 2.63 times more severe among working participants when examining predictors of alexithymia. When evaluating the correlations between alexithymia and HbA1c or fasting blood glucose levels we found strong associations equal to 0.75 and 0.77 for TAS-20 total scores, respectively. While alexithymic participants showed significantly higher levels of HbA1c and blood glucose when compared to the non-alexithymic participants. Conclusions: The results of this systematic review of the current literature highlight the need of alexithymia evaluation in patients with T2DM. The high prevalence in T2DM and strong associations with poorly regulated diabetes and psychological distress, indicate a significant relationship between poor glycemic control and psychological distress, such as anxiety and depression, and quality of life. Further studies are needed focusing on age and gender differences in order to be able to improve clinical psychological care and prevention.

Type 2 diabetes differentially affects the substrate saturation kinetic attributes of erythrocyte hexokinase and phosphofructokinase

The substrate kinetic parameters of hexokinase (HK) and phosphofructokinase (PFK)-the key irreversible enzymes of glycolysis-in erythrocytes from type 2 diabetic subjects were examined in comparison with control subjects. It was observed that the kinetic parameters such as K_m , V_max , Apparent K_cat , K_cat /K_m , and substrate (ATP) inhibition kinetic and substrate binding characteristics are significantly altered in the diabetic group. The observed changes are suggestive of compositional changes in the subunit makeup of HK and PFK. The implication of these findings in relation to energy status of the diabetic erythrocyte and its interrelationship with loss of cell deformability are discussed here.

Responsivity of lateral septum-mPFC connections in alloxan-induced hyperglycemia

The lateral septal nucleus (LSN) is related to the actions of antidepressants, and the prelimbic cortex (PL) and infralimbic cortex (IL) modulate responses to fear. However, unknown is whether experimental diabetes that is induced by alloxan alters the responsivity of these regions. We used a method in which one forebrain region (LSN) was electrically stimulated while single-unit extracellular recordings were performed in another mPFC region (PL and IL). Several experimental groups were tested: (a) animals that were subjected to long-term (42-day) alloxan-hyperglycemia and protected with insulin, (b) healthy animals that received a low dose of insulin that does not produce changes in glycemia, and (c) animals that received long-term treatment with fluoxetine. Additional healthy groups of animals received insulin or fluoxetine and underwent the forced swim test. Biological measurements indicated the induction of diabetes in alloxan-treated rats. In this group, a shift toward an inhibitory response to LSN stimulation was observed in the PL and IL compared with the control group. A low dose of insulin or fluoxetine produced similar changes in LSN-PL and LSN-IL responsivity. Long-term hyperglycemia increased inhibitory responsivity in the LSN-PL and LSN-IL, but this action was less pronounced than the action that was exerted by insulin and fluoxetine, which produced similar actions. Such similar actions were confirmed in the forced swim test, in which the antidepressant-like effects of insulin partially resembled the effects of fluoxetine. The changes that were observed in the alloxan group appeared to be related to neuronal damage, and a low dose of insulin exerted some antidepressant-like actions.

Impact of alexithymia on glycemic control among Lebanese adults with type 2 diabetes

Purpose

Alexithymia, defined as the inability of a person to identify, describe and express emotions, has been found to influence glycemic control in type 2 diabetes patients (D2). The characteristics and influencing factors of alexithymia and the association of this psychological construct with D2 has not yet been studied in Lebanon where 14.6% of adults are diagnosed with the disease. This study aims at evaluating the prevalence of alexithymia and its relationship with glycemic control among Lebanese adults with D2.

Methods

Alexithymia was assessed in 104 patients diagnosed with D2 and 100 healthy controls using the 20-item Toronto Alexithymia Scale (TAS-20). The impact of alexithymia on glycemic control was evaluated using HbA1c values, fasting blood glucose levels, number of severe hyperglycemic episodes and hospitalizations for hyperglycemia within the past months.

Results

Alexithymia prevalence was significantly higher in D2 patients compared to controls (35.5% vs 15%). Patients with alexithymia showed higher levels of HbA1c and glucose in comparison to those without alexithymia. Consistently, significant positive correlations were found between the TAS-20 total and subscale scores and both HbA1c and glucose levels. Alexithymic patients had three times more severe hyperglycemic episodes and five times more hospitalizations for hyperglycemia compared to those without alexithymia. According to multivariate regression analysis, lifestyle factors alone were not found predictive of alexithymia in D2 patients.

Conclusion

Given the impact of alexithymia on D2 regulation, screening of alexithymia in case of D2 and appropriate psychological follow-up are important for a better prognosis, management and treatment of the disease.

Cognitive Impairment and its Association with Glycemic Control in Type 2 Diabetes Mellitus Patients

INTRODUCTION

Type 2 diabetes mellitus is one of the major causes of increasing morbidity worldwide. Effective screening is carried out routinely for diabetic retinopathy, neuropathy, and nephropathy. Of late, studies have reported that cognitive decline can occur in people with diabetes, which could go undetected for a long period, and hence routine screening could be warranted.

METHODOLOGY

Our objective was to study the prevalence of previously unknown mild cognitive impairment (MCI) in type 2 diabetic patients visiting a tertiary care center with the Montreal Cognitive Assessment (MoCA) test and to study the correlations of HbA1c, fasting blood sugar (FBS), postprandial blood sugar (PPBS), age, and duration of diabetes with the MoCA scores. Seventy patients with type 2 diabetes mellitus were included in the study. Patients with MoCA scores ≥26 were considered to have normal cognition (NC) and those with <26 MCI.

RESULTS

MCI was noted in 38 (54.29%) type 2 diabetes mellitus patients and NC in 32 (45.71%). Those with MCI had higher HbA1c (8.79 ± 1.85 vs. 7.78 ± 1.60), higher FBS (177.05 ± 62.48 vs. 149.38 ± 54.38), and PPBS (282.03 ± 85.61 vs. 214.50 ± 82.43), which were statistically significant. The cognitive domains of executive function, naming, attention, language, and memory showed a statistically significant difference between those with MCI and NC. There were no differences in the mean age, duration of diabetes, and educational status between the groups.

CONCLUSION

The high prevalence of MCI in type 2 diabetic patients highlights the importance of implementing routine cognitive testing. The correlation of cognitive impairment with poor glucose control needs further studies to find out whether improving glycemic control will help improve cognition.