True or false? Alzheimer's disease is type 3 diabetes: Evidences from bench to bedside

Globally, Alzheimer's disease (AD) is the most widespread chronic neurodegenerative disorder, leading to cognitive impairment, such as aphasia and agnosia, as well as mental symptoms, like behavioral abnormalities, that place a heavy psychological and financial burden on the families of the afflicted. Unfortunately, no particular medications exist to treat AD, as the current treatments only impede its progression.The link between AD and type 2 diabetes (T2D) has been increasingly revealed by research; the danger of developing both AD and T2D rises exponentially with age, with T2D being especially prone to AD. This has propelled researchers to investigate the mechanism(s) underlying this connection. A critical review of the relationship between insulin resistance, Aβ, oxidative stress, mitochondrial hypothesis, abnormal phosphorylation of Tau protein, inflammatory response, high blood glucose levels, neurotransmitters and signaling pathways, vascular issues in AD and diabetes, and the similarities between the two diseases, is presented in this review. Grasping the essential mechanisms behind this detrimental interaction may offer chances to devise successful therapeutic strategies.

Oral phytate supplementation on the progression of mild cognitive impairment, brain iron deposition and diabetic retinopathy in patients with type 2 diabetes: a concept paper for a randomized double blind placebo controlled trial (the PHYND trial)

Type 2 diabetes mellitus has a worldwide prevalence of 10.5% in the adult population (20-79 years), and by 2045, the prevalence is expected to keep rising to one in eight adults living with diabetes. Mild cognitive impairment has a global prevalence of 19.7% in adults aged 50 years. Both conditions have shown a concerning increase in prevalence rates over the past 10 years, highlighting a growing public health challenge. Future forecasts indicate that the prevalence of dementia (no estimations done for individuals with mild cognitive impairment) is expected to nearly triple by 2050. Type 2 diabetes mellitus is a risk factor for the development of cognitive impairment, and such impairment increase the likelihood of poor glycemic/metabolic control. High phytate intake has been shown to be a protective factor against the development of cognitive impairment in observational studies. Diary phytate intake might reduce the micro- and macrovascular complications of patients with type 2 diabetes mellitus through different mechanisms. We describe the protocol of the first trial (the PHYND trial) that evaluate the effect of daily phytate supplementation over 56 weeks with a two-arm double-blind placebo-controlled study on the progression of mild cognitive impairment, cerebral iron deposition, and retinal involvement in patients with type 2 diabetes mellitus. Our hypothesis proposes that phytate, by inhibiting advanced glycation end product formation and chelating transition metals, will improve cognitive function and attenuate the progression from Mild Cognitive Impairment to dementia in individuals with type 2 diabetes mellitus and mild cognitive impairment. Additionally, we predict that phytate will reduce iron accumulation in the central nervous system, mitigate neurodegenerative changes in both the central nervous system and retina, and induce alterations in biochemical markers associated with neurodegeneration.

Evaluating the Preferences and Willingness-to-Pay for Oral Antidiabetic Drugs Among Patients with Type 2 Diabetes Mellitus in China: A Discrete Choice Experiment

PURPOSE

To quantify the preferences for an oral antidiabetic drug (OAD) among patients with type 2 diabetes mellitus (T2DM) in China.

METHODS

A discrete choice experiment (DCE) with hypothetical OAD profiles was performed among patients with T2DM recruited from both online and offline sources. Each patient completed 12 DCE choice tasks. The attributes, elicited through mixed methods, include blood glucose level decrease, blood glucose level stability, frequency of medication, gastrointestinal side effects, dose adjustment and out-of-pocket expense. The conditional logit regression model was used to analyze the data. Patients' willingness-to-pay (WTP) was also calculated. Subgroup analyses based on patient characteristics were also conducted.

RESULTS

A total of 741 respondents were included in the analysis sample, covering 456 respondents online and 285 offline. The result showed that all attributes and levels were statistically significant, except one level "dose adjustment required for patients with hepatic or renal insufficiency" in the attribute of dose adjustment. WTP results showed that patients were willing to pay 12.06 and 23.20 yuan, respectively to reduce the frequency of medication from "once per day" and "three times per day" to "once every 2 weeks", respectively. Subgroup analyses showed that the frequency of medication (once versus two to three times per day) had the largest impact and influenced most coefficient estimates.

CONCLUSION

The results suggest that Chinese patients with T2DM prioritized better efficacy, less frequency of medication, lower gastrointestinal side effects, no dose adjustment required for patients with hepatic or renal insufficiency, and less out-of-pocket expense of OAD treatment.

Alzheimer's disease as a causal risk factor for diabetic retinopathy: a Mendelian randomization study

Objectives

This study aims to investigate the causal relationship between Alzheimer's Disease (AD) and Diabetic Retinopathy (DR).

Methods

Employing Mendelian Randomization (MR), Generalized Summary-data-based Mendelian Randomization (GSMR), and the MR-Steiger test, this study scrutinizes the genetic underpinnings of the hypothesized causal association between AD and DR, as well as its Proliferative DR (PDR) and Non-Proliferative DR (NPDR) subtypes. Comprehensive data from Genome-Wide Association Studies (GWAS) were analyzed, specifically AD data from the Psychiatric Genomics Consortium (71,880 cases/383,378 controls), and DR, PDR, and NPDR data from both the FinnGen consortium (FinnGen release R8, DR: 5,988 cases/314,042 controls; PDR: 8,383 cases/329,756 controls; NPDR: 3,446 cases/314,042 controls) and the IEU OpenGWAS (DR: 14,584 cases/176,010 controls; PDR: 8,681 cases/204,208 controls; NPDR: 2,026 cases/204,208 controls). The study also incorporated Functional Mapping and Annotation (FUMA) for an in-depth analysis of the GWAS results.

Results

The MR analyses revealed that genetic susceptibility to AD significantly increases the risk of DR, as evidenced by GWAS data from the FinnGen consortium (OR: 2.5090; 95% confidence interval (CI):1.2102-5.2018, false discovery rate P-value (PFDR)=0.0201; GSMR: bxy=0.8936, bxy_se=0.3759, P=0.0174), NPDR (OR: 2.7455; 95% CI: 1.3178-5.7197, PFDR=0.0166; GSMR: bxy=0.9682, bxy_se=0.3802, P=0.0126), and PDR (OR: 2.3098; 95% CI: 1.2411-4.2986, PFDR=0.0164; GSMR: bxy=0.7962, bxy_se=0.3205, P=0.0129) using DR GWAS from FinnGen consortium. These results were corroborated by DR GWAS datasets from IEU OpenGWAS. The MR-Steiger test confirmed a significant association of all identified instrumental variables (IVs) with AD. While a potential causal effect of DR and its subtypes on AD was identified, the robustness of these results was constrained by a low power value. FUMA analysis identified OARD1, NFYA, TREM1 as shared risk genes between DR and AD, suggesting a potential genetic overlap between these complex diseases.

Discussion

This study underscores the contribution of AD to an increased risk of DR, as well as NPDR and PDR subtypes, underscoring the necessity of a holistic approach in the management of patients affected by these conditions.

Interaction of aerobic exercise and crocin improves memory, learning and hypocampic tau and neurotrophins gene expression in rats treated with trimethytin as a model of Alzheimer's disease

INTRODUCTION

Alzheimer's disease (AD) is characterized by progressive cognitive decline and a reduction in hippocampal neurotrophins, in which trimethytin (TMT) infusion causes tangles and neuronal dysfunction, creating an AD-like model in rats. Previous studies have demonstrated that crocin, which has anti-inflammatory properties, can enhance learning, memory acquisition, and cognitive behavior. This study aimed to assess the combined impact of aerobic exercise and crocin on memory, learning, and hippocampal Tau and neurotrophins gene expression in AD-like model rats.

METHODS

Forty male Sprague Dawley rats were randomly divided into five groups: (1) healthy control, (2) Alzheimer's control, (3) endurance training, (4) crocin consumption, and (5) endurance training + crocin. Alzheimer's induction was achieved in groups 2-5 through intraperitoneal injection of 8 mg/kg TMT. Rats in groups 3 and 5 engaged in treadmill running three sessions per week, 15-30 min per session, at a speed of 15-20 m/min for eight weeks, and groups 4 and 5 received daily crocin supplementation of 25 mg/kg.

RESULTS

Alzheimer's induction with TMT showed significant reduction in memory, learning, NGF, BDNF, and TrkB gene expression, and increase in tau gene expression (all p < 0.05). Notably, endurance training and crocin consumption separately significantly increased memory, learning, NGF, BDNF, and TrkB gene expression while significantly decreasing tau gene expression (all p < 0.05). Importantly, combined endurance training with crocin yielded the most profound effects on memory (p = 0.001), NGF (p = 0.002), BDNF (p = 0.001), and TrkB (p = 0.003) gene expression (p < 0.005), as well as a reduction in tau gene expression (p = 0.001).

CONCLUSION

These findings underscore the possible impact of endurance training, particularly when coupled with crocin, on enhancing memory, learning, and neurotrophin gene expression and reducing tau gene expression in Alzheimer's rats. These results highlight the possibility of synergistic interventions for improved therapeutic outcomes.

Association of metabolic dysfunction with cognitive decline and Alzheimer's disease: A review of metabolomic evidence

The discovery of new biomarkers that can distinguish Alzheimer's disease (AD) from mild cognitive impairment (MCI) in the early stages will help to provide new diagnostic and therapeutic strategies and slow the transition from MCI to AD. Patients with AD may present with a concomitant metabolic disorder, such as diabetes, obesity, and dyslipidemia, as a risk factor for AD that may be involved in the onset of both AD pathology and cognitive impairment. Therefore, metabolite profiling, or metabolomics, can be very useful in diagnosing AD, developing new therapeutic targets, and evaluating both the course of treatment and the clinical course of the disease. In addition, studying the relationship between nutritional behavior and AD requires investigation of the role of conditions such as obesity, hypertension, dyslipidemia, and elevated glucose level. Based on this literature review, nutritional recommendations, including weight loss by reducing calorie and cholesterol intake and omega-3 fatty acid supplementation can prevent cognitive decline and dementia in the elderly. The underlying metabolic causes of the pathology and cognitive decline caused by AD and MCI are not well understood. In this review article, metabolomics biomarkers for diagnosis of AD and MCI and metabolic risk factors for cognitive decline in AD were evaluated.

Bitter yet beneficial: The dual role of dietary alkaloids in managing diabetes and enhancing cognitive function

With the rising prevalence of diabetes and its association with cognitive impairment, interest in the use of dietary alkaloids and other natural products has grown significantly. Understanding how these compounds manage diabetic cognitive dysfunction (DCD) is crucial. This comprehensive review explores the etiology of DCD and the effects of alkaloids in foods and dietary supplements that have been investigated as DCD therapies. Data on how dietary alkaloids like berberine, trigonelline, caffeine, capsaicin, 1-deoxynojirimycin, nuciferine, neferine, aegeline, tetramethylpyrazine, piperine, and others regulate cognition in diabetic disorders were collected from PubMed, Research Gate, Web of Science, Science Direct, and other relevant databases. Dietary alkaloids could improve memory in behavioral models and modulate the mechanisms underlying the cognitive benefits of these compounds, including their effects on glucose metabolism, gut microbiota, vasculopathy, neuroinflammation, and oxidative stress. Evidence suggests that dietary alkaloids hold promise for improving cognition in diabetic patients and could open exciting avenues for future research in diabetes management.

Communal interaction of glycation and gut microbes in diabetes mellitus, Alzheimer's disease, and Parkinson's disease pathogenesis

Diabetes and its complications, Alzheimer's disease (AD), and Parkinson's disease (PD) are increasing gradually, reflecting a global threat vis-à-vis expressing the essentiality of a substantial paradigm shift in research and remedial actions. Protein glycation is influenced by several factors, like time, temperature, pH, metal ions, and the half-life of the protein. Surprisingly, most proteins associated with metabolic and neurodegenerative disorders are generally long-lived and hence susceptible to glycation. Remarkably, proteins linked with diabetes, AD, and PD share this characteristic. This modulates protein's structure, aggregation tendency, and toxicity, highlighting renovated attention. Gut microbes and microbial metabolites marked their importance in human health and diseases. Though many scientific shreds of evidence are proposed for possible change and dysbiosis in gut flora in these diseases, very little is known about the mechanisms. Screening and unfolding their functionality in metabolic and neurodegenerative disorders is essential in hunting the gut treasure. Therefore, it is imperative to evaluate the role of glycation as a common link in diabetes and neurodegenerative diseases, which helps to clarify if modulation of nonenzymatic glycation may act as a beneficial therapeutic strategy and gut microbes/metabolites may answer some of the crucial questions. This review briefly emphasizes the common functional attributes of glycation and gut microbes, the possible linkages, and discusses current treatment options and therapeutic challenges.

Metformin: The Winding Path from Understanding Its Molecular Mechanisms to Proving Therapeutic Benefits in Neurodegenerative Disorders

Metformin, a widely prescribed medication for type 2 diabetes, has garnered increasing attention for its potential neuroprotective properties due to the growing demand for treatments for Alzheimer's, Parkinson's, and motor neuron diseases. This review synthesizes experimental and clinical studies on metformin's mechanisms of action and potential therapeutic benefits for neurodegenerative disorders. A comprehensive search of electronic databases, including PubMed, MEDLINE, Embase, and Cochrane library, focused on key phrases such as "metformin", "neuroprotection", and "neurodegenerative diseases", with data up to September 2023. Recent research on metformin's glucoregulatory mechanisms reveals new molecular targets, including the activation of the LKB1-AMPK signaling pathway, which is crucial for chronic administration of metformin. The pleiotropic impact may involve other stress kinases that are acutely activated. The precise role of respiratory chain complexes (I and IV), of the mitochondrial targets, or of the lysosomes in metformin effects remains to be established by further research. Research on extrahepatic targets like the gut and microbiota, as well as its antioxidant and immunomodulatory properties, is crucial for understanding neurodegenerative disorders. Experimental data on animal models shows promising results, but clinical studies are inconclusive. Understanding the molecular targets and mechanisms of its effects could help design clinical trials to explore and, hopefully, prove its therapeutic effects in neurodegenerative conditions.

MiR-29b modulates DNA methylation in promoter region of miR-130b in mouse model of Diabetic nephropathy

Epigenetic modifications play a role in Diabetic Nephropathy (DN). Downregulation of miR-29b leads to modulation of DNA methylation via DNA methyl transferases (DNMTs) and hence exaggerated renal fibrosis in DN. Therefore, the main aim of the study was to evaluate effect of miR-29b expression in vivo on DNMTs, renal fibrosis, glomerular and tubular damage as well as renal morphology in DN. In order to explore the role of miR-29b in DNA methylation of other miRNAs, methylation profiling study was performed. It revealed that miR-29b was involved in methylation on of miR-130b on the cytosine guanine dinucleotides rich DNA (CpG) island 1 located on promoter region. In conclusion, miR-29b expression was found to modulate DNA methylation via DNMTs and regulate methylation of miR-130b. The result of this study provides a future direction to unveil role of miRNA expression in DNA methylation and its consequent effect on other miRNAs in DN.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01208-2.

Pathological Impact of Tau Proteolytical Process on Neuronal and Mitochondrial Function: a Crucial Role in Alzheimer's Disease

Tau protein plays a pivotal role in the central nervous system (CNS), participating in microtubule stability, axonal transport, and synaptic communication. Research interest has focused on studying the role of post-translational tau modifications in mitochondrial failure, oxidative damage, and synaptic impairment in Alzheimer's disease (AD). Soluble tau forms produced by its pathological cleaved induced by caspases could lead to neuronal injury contributing to oxidative damage and cognitive decline in AD. For example, the presence of tau cleaved by caspase-3 has been suggested as a relevant factor in AD and is considered a previous event before neurofibrillary tangles (NFTs) formation.Interestingly, we and others have shown that caspase-cleaved tau in N- or C- terminal sites induce mitochondrial bioenergetics defects, axonal transport impairment, neuronal injury, and cognitive decline in neuronal cells and murine models. All these abnormalities are considered relevant in the early neurodegenerative manifestations such as memory and cognitive failure reported in AD. Therefore, in this review, we will discuss for the first time the importance of truncated tau by caspases activation in the pathogenesis of AD and how its negative actions could impact neuronal function.

Peripheral origin exosomal microRNAs aggravate glymphatic system dysfunction in diabetic cognitive impairment

Cognitive dysfunction is one of the common central nervous systems (CNS) complications of diabetes mellitus, which seriously affects the quality of life of patients and results in a huge economic burden. The glymphatic system dysfunction mediated by aquaporin-4 (AQP4) loss or redistribution in perivascular astrocyte endfeet plays a crucial role in diabetes-induced cognitive impairment (DCI). However, the mechanism of AQP4 loss or redistribution in the diabetic states remains unclear. Accumulating evidence suggests that peripheral insulin resistance target tissues and CNS communication affect brain homeostasis and that exosomal miRNAs are key mediators. Glucose and lipid metabolism disorder is an important pathological feature of diabetes mellitus, and skeletal muscle, liver and adipose tissue are the key target insulin resistance organs. In this review, the changes in exosomal miRNAs induced by peripheral metabolism disorders in diabetes mellitus were systematically reviewed. We focused on exosomal miRNAs that could induce low AQP4 expression and redistribution in perivascular astrocyte endfeet, which could provide an interorgan communication pathway to illustrate the pathogenesis of DCI. Furthermore, the mechanisms of exosome secretion from peripheral insulin resistance target tissue and absorption to the CNS were summarized, which will be beneficial for proposing novel and feasible strategies to optimize DCI prevention and/or treatment in diabetic patients.

Voxel-based morphometry reveals the correlation between gray matter volume and serum P-tau-181 in type 2 diabetes mellitus patients with different HbA1c levels

Introduction

Emerging evidence suggested widespread decreased gray matter volume (GMV) and tau hyperphosphorylation were associated with type 2 diabetes mellitus (T2DM). Insulin resistance is one of the mechanisms of neuron degeneration in T2DM; it can decrease the activity of protein kinase B and increase the activity of glycogen synthesis kinase-3β, thus promoting the hyperphosphorylation of tau protein and finally leading to neuronal degeneration. However, the association between GMV and serum tau protein phosphorylated at threonine 181 (P-tau-181) in T2DM patients lacks neuroimaging evidence. We aimed to investigate the difference in brain GMV between T2DM patients with different glycated hemoglobin A1c (HbA1c) levels and healthy control (HC) subjects and the correlation between serum P-tau-181 and GMV in T2DM patients.

Methods

Clinical parameters, biochemical indicators, and MRI data were collected for 41 T2DM patients with high glycosylated hemoglobin level (HGL), 17 T2DM patients with normal glycosylated hemoglobin level (NGL), and 42 HC subjects. Voxel-based morphometry (VBM) method was applied to investigate GMV differences among groups, and multiple regression analysis was used to examine the correlation between serum P-tau-181 and GMV.

Results

Compared with HC subjects, the T2DM patients with HGL or NGL all showed significantly decreased GMV. Briefly, the GMV decreased in T2DM patients with HGL was mainly in the bilateral parahippocampal gyrus (PHG), right middle temporal gyrus (MTG), temporal pole (TPOmid), hippocampus (HIP), and left lingual gyrus. The GMV reduction in T2DM patients with NGL was in the right superior temporal gyrus (STG), and there was no significant difference in GMV between the two diabetic groups. The GMV values of bilateral PHG, right MTG, TPOmid, HIP, and STG can significantly (p < 0.0001) distinguish T2DM patients from HC subjects in ROC curve analysis. In addition, we found that serum P-tau-181 levels were positively correlated with GMV in the right superior and middle occipital gyrus and cuneus, and negatively correlated with GMV in the right inferior temporal gyrus in T2DM patients.

Conclusion

Our study shows that GMV atrophy can be used as a potential biological indicator of T2DM and also emphasizes the important role of P-tau-181 in diabetic brain injury, providing new insights into the neuropathological mechanism of diabetic encephalopathy.

Cognitive protection of incretin-based therapies in patients with type 2 diabetes mellitus: A systematic review and meta-analysis based on clinical studies

AIMS/INTRODUCTION

Cognitive dysfunction, including mild cognitive impairment and dementia, is increasingly recognized as an important complication of type 2 diabetes mellitus. The aims of the preset study was to investigate the cognitive protection of incretin-based therapies, including glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors, in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

PubMed, EMBASE, Cochrane library, Web of Science and PsycINFO were searched from the inception through 17 January 2023 for randomized controlled trials and cohort studies on the association between incretin-based therapies and cognitive function. A total of 15 studies were finally included in our systematic review, and eight of which were incorporated into our meta-analysis.

RESULTS

Pooled results showed that the Mini-Mental State Examination score in incretin-based therapy groups was increased by 1.20 compared with the control group (weighted mean difference 1.20, 95% confidence interval 0.39-2.01). The results of eight studies assessed by the Newcastle Ottawa Quality Assessment Scale and the Cochrane Collaboration's tool, and the quality of the eight studies were at a relatively high level. Egger's regression did not show significant publication bias.

CONCLUSIONS

Current evidence shows that incretin-based therapies might be more effective, when compared with the other hypoglycemic drugs, for cognitive improvement in patients with type 2 diabetes mellitus.

Assessment of cognitive impairment and depressive signs in patients with type 2 diabetes treated with metformin from Southeast Mexico: A cross-sectional study

Multiple factors associate diabetes with cognitive impairment and depression. Antidiabetic drugs have reported antidepressant and pro-cognitive effects in diabetic and non-diabetic subjects. Antidepressant and pro-cognitive effects of metformin are reported in various studies; however, these effects are not consistent among researches. We designed a cross-sectional study. We recruited patients with T2D diagnosis from the Diabetes Clinic of the Regional Hospital of High Specialty "Dr. Gustavo A. Rovirosa Pérez" from January 2019 to May 2022. We included 431 subjects with T2D, 374 patients with metformin treatment and 57 subjects without metformin. These patients were on intensive therapies and had not a previous diagnosis of cognitive impairment or depression. We applied Mini-Mental State Examination (MMSE) to evaluate cognitive impairment, and Hamilton Depression Rating Scale (HAM-D) to assess depressive signs. Our sample had a mean age of 53.77 ± 13.43 years. Metformin users were 374 individuals, and 57 subjects didn't use metformin. MMSE found cognitive impairment in 8.3% (n = 31) of metformin users, and 14.8% (n = 8) of patients without metformin. HAM-D scale showed that 39.5% (n = 147) of patients with metformin had depression signs, subjects without metformin and depressive signs were 44.6% (n = 25). We found no differences between groups for cognitive impairment and depression grades. We did not find associations between metformin treatment, cognitive impairment measures and depression sign measures. However, chronic metformin treatment, insulin use, glycemic control and age could influence our results.

Rooibos tea-in the cross fire of ROS, mitochondrial dysfunction and loss of proteostasis-positioned for healthy aging

Impaired mitochondrial function and loss of cellular proteostasis control are key hallmarks of aging and are implicated in the development of neurodegenerative diseases. A common denominator is the cell's inability to handle reactive oxygen species (ROS), leading to major downstream oxidative damage that exacerbates neuronal dysfunction. Although we have progressed in understanding the molecular defects associated with neuronal aging, many unanswered questions remain. How much ROS is required to serve cellular function before it becomes detrimental and how does the cell's oxidative status impact mitochondrial function and protein degradation through autophagy? How does ROS regulate autophagy? Aspalathus linearis, also commonly known as rooibos, is an endemic South African plant that is gaining globally acclaim for its antioxidant properties and its role as functional medicinal beverage. In this article we dissect the role of rooibos in the context of the cell's ROS handling capacity, mitochondrial function and autophagy activity. By addressing the dynamic relationship between these critical interconnected systems, and by evaluating the functional properties of rooibos, we unravel its position for preserving cell viability and promoting healthy aging.

Aberrant lncRNA expression in patients with proliferative diabetic retinopathy: preliminary results from a single-center observational study

BACKGROUND

Diabetic retinopathy (DR) is a leading cause of blindness. Vision threat is particularly severe in patients with retinal neovascularization. However, little is known about the role of long noncoding RNAs (lncRNAs) in proliferative diabetic retinopathy (PDR). The goal of this study was to identify lncRNAs involved in PDR.

METHODS

We compared lncRNA expression profiles in the vitreous between patients with PDR and those with idiopathic macular hole (IMH) and between patients with PDR who had received anti-vascular endothelial growth factor (VEGF) therapy and those who had not. Vitreous samples from patients with PDR and IMH were screened for lncRNAs using microarray-based analysis, and quantitative real-time polymerase chain reaction (qRT-PCR) was used to confirm the microarray results. Bioinformatic analysis was also performed. Moreover, the effect of anti-VEGF therapy was investigated in vitreous samples of patients with PDR treated with anti-VEGF therapy and those who were not.

RESULTS

A total of 1067 differentially expressed noncoding RNA transcripts were found during screening in the vitreous humor of patients with PDR than in those with IMH. Five lncRNAs were subjected to qRT-PCR. RP11-573 J24.1, RP11-787B4.2, RP11-654G14.1, RP11-2A4.3, and RP11-502I4.3 were significantly downregulated; this was validated by the comparison using the microarray data. In addition, 835 differentially expressed noncoding RNA transcripts were found during screening in the vitreous humor of patients with PDR treated with anti-VEGF therapy compared with untreated PDR patients. RP4-631H13.2 was significantly upregulated, which is consistent with the trend of the microarray analysis.

CONCLUSIONS

There were systemic expression differences in the vitreous at the microarray level between patients with PDR and those with IMH and between patients with PDR after anti-VEGF treatment and those that did not receive anti-VEGF treatment. LncRNAs identified in the vitreous humor may be a novel research field for PDR.

Inhibition of ferroptosis through regulating neuronal calcium homeostasis: An emerging therapeutic target for Alzheimer's disease

Alzheimer's disease (AD), a chronic and progressive neurodegenerative disease, generates a serious threat to the health of the elderly. The AD brain is microscopically characterized by amyloid plaques and neurofibrillary tangles. There are still no effective therapeutic drugs to restrain the progression of AD though much attention has been paid to exploit AD treatments. Ferroptosis, a type of programmed cell death, has been reported to promote the pathological occurrence and development of AD, and inhibition of neuronal ferroptosis can effectively improve the cognitive impairment of AD. Studies have shown that calcium (Ca²⁺) dyshomeostasis is closely related to the pathology of AD, and can drive the occurrence of ferroptosis through several pathways, such as interacting with iron, and regulating the crosstalk between endoplasmic reticulum (ER) and mitochondria. This paper mainly reviews the roles of ferroptosis and Ca²⁺ in the pathology of AD, and highlights that restraining ferroptosis through maintaining the homeostasis of Ca²⁺ may be an innovative target for the treatment of AD.

Relationship between glycemic control and cognitive impairment: A systematic review and meta-analysis

Background

Diabetes mellitus, or hyperglycemia, is an independent risk factor for cognitive impairment. Here we systematically analyzed whether glycemic control could improve cognitive impairment in patients with diabetes mellitus (DM), hyperglycemia, or insulin resistance.

Methods

Three databases (PubMed, EMBASE, and Cochrane Library) and ClinicalTrials.gov were searched for randomized controlled trials analyzing the relationship between glycemic control and cognitive function assessments, published from database inception to June 2022. Patients in experimental groups were treated with antidiabetic drugs, while control groups were treated with a placebo or alternative antidiabetic drugs. Data analysis was conducted using RevMan 5.3 and StataSE-64, and standardized mean difference (SMD) and 95% confidence intervals (CIs) were calculated.

Results

Thirteen studies comprising 19,314 participants were included. Analysis revealed that glycemic control significantly attenuated the degree of decline in cognitive function assessment scores (SMD  =  0.15; 95% CI 0.05, 0.26; p  <  0.00001), and funnel plots confirmed no publication bias. Seven studies used Mini-Mental State Examination as the primary cognitive function assessment, showing that glycemic control significantly delayed the degree of decline in cognitive function assessment scores (SMD  =  0.18; 95% CI 0.03, 0.34; p  =  0.02). Similar results were seen in two studies using the Montreal Cognitive Assessment scale, but without significant difference (SMD  =  0.05; 95% CI-0.10, 0.21; p  =  0.51). One study using Auditory Word Learning Test (AVLT) showed that glycemic control significantly delayed the decline in cognitive function assessment scores (SMD  =  0.52; 95% CI 0.11,0.93; p  =  0.01), and another used Wechsler Memory Scale Revised, showing similar results (SMD  =  1.45; 95% CI 0.86, 2.04; p  <  0.00001). Likewise, a study that used Modified Mini-Mental State scale showed that glycemic control significantly delayed the decline in cognitive function assessment scores (SMD  =  -0.10; 95% CI-0.16, -0.03; p  =  0.005). Lastly, one study used AVLT subtests to show that glycemic control delayed the decline in cognitive function assessment scores, although not statistically significant (SMD  =  0.09; 95% CI-0.53, 0.71; p  =  0.78).

Conclusion

Glycemic control through antidiabetic treatment correlates with the improvement of cognitive impairment in patients with DM, hyperglycemia or insulin resistance. However, further studies are needed to validate the results of this study.

Systematic Review Registration

PROSPERO, identifier CRD42022342260.

Saffron as a promising therapy for diabetes and Alzheimer's disease: mechanistic insights

The prevalence of both Alzheimer's disease (AD) and diabetes mellitus is increasing with the societies' aging and has become an essential social concern worldwide. Accumulation of amyloid plaques and neurofibrillary tangles (NFTs) of tau proteins in the brain are hallmarks of AD. Diabetes is an underlying risk factor for AD. Insulin resistance has been proposed to be involved in amyloid-beta (Aβ) aggregation in the brain. It seems that diabetic conditions can result in AD pathology by setting off a cascade of processes, including inflammation, mitochondrial dysfunction, and ROS and advanced glycation end products (AGEs) synthesis. Due to the several side effects of chemical drugs and their high cost, using herbal medicine has recently attracted attention for the treatment of diabetes and AD. Saffron and its active ingredients have been used for its anti-inflammatory, anti-oxidant, anti-diabetic, and anti-AD properties. Therefore, in the present review paper, we take account of the clinical, in vivo and in vitro evidence regarding the anti-diabetic and anti-AD effects of saffron and discuss the preventive or postponing properties of saffron or its components on AD development via its anti-diabetic effects.

Prevailing Antagonistic Risks in Pleiotropic Associations with Alzheimer's Disease and Diabetes

BACKGROUND

The lack of efficient preventive interventions against Alzheimer's disease (AD) calls for identifying efficient modifiable risk factors for AD. As diabetes shares many pathological processes with AD, including accumulation of amyloid plaques and neurofibrillary tangles, insulin resistance, and impaired glucose metabolism, diabetes is thought to be a potentially modifiable risk factor for AD. Mounting evidence suggests that links between AD and diabetes may be more complex than previously believed.

OBJECTIVE

To examine the pleiotropic architecture of AD and diabetes mellitus (DM).

METHODS

Univariate and pleiotropic analyses were performed following the discovery-replication strategy using individual-level data from 10 large-scale studies.

RESULTS

We report a potentially novel pleiotropic NOTCH2 gene, with a minor allele of rs5025718 associated with increased risks of both AD and DM. We confirm previously identified antagonistic associations of the same variants with the risks of AD and DM in the HLA and APOE gene clusters. We show multiple antagonistic associations of the same variants with AD and DM in the HLA cluster, which were not explained by the lead SNP in this cluster. Although the ɛ2 and ɛ4 alleles played a major role in the antagonistic associations with AD and DM in the APOE cluster, we identified non-overlapping SNPs in this cluster, which were adversely and beneficially associated with AD and DM independently of the ɛ2 and ɛ4 alleles.

CONCLUSION

This study emphasizes differences and similarities in the heterogeneous genetic architectures of AD and DM, which may differentiate the pathogenic mechanisms of these diseases.

Molecular mechanisms underlying hyperglycemia associated cognitive decline

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia. DM can lead to a number of secondary complications affecting multiple organs in the body including the eyes, kidney, heart, and brain. The most common effect of hyperglycemia on the brain is cognitive decline. It has been estimated that 20-70% of people with DM have cognitive deficits. High blood sugar affects key brain areas involved in learning, memory, and spatial navigation, and the structural complexity of the brain has made it prone to a variety of pathological disorders, including T2DM. Studies have reported that cognitive decline can occur in people with diabetes, which could go undetected for several years. Moreover, studies on brain imaging suggest extensive effects on different brain regions in patients with T2D. It remains unclear whether diabetes-associated cognitive decline is a consequence of hyperglycemia or a complication that co-occurs with T2D. The exact mechanism underlying cognitive impairment in diabetes is complex; however, impaired glucose metabolism and abnormal insulin function are thought to play important roles. In this review, we have tried to summarize the effect of hyperglycemia on the brain structure and functions, along with the potential mechanisms underlying T2DM-associated cognitive decline.

Arginine Reduces Glycation in γ2 Subunit of AMPK and Pathologies in Alzheimer's Disease Model Mice

The metabolism disorders are a common convergence of Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM). The characteristics of AD are senile plaques and neurofibrillary tangles (NFTs) composed by deposits of amyloid-β (Aβ) and phosphorylated tau, respectively. Advanced glycation end-products (AGEs) are a stable modification of proteins by non-enzymatic reactions, which could result in the protein dysfunction. AGEs are associated with some disease developments, such as diabetes mellitus and AD, but the effects of the glycated γ2 subunit of AMPK on its activity and the roles in AD onset are unknown.

METHODS

We studied the effect of glycated γ2 subunit of AMPK on its activity in N2a cells. In 3 × Tg mice, we administrated L-arginine once every two days for 45 days and evaluated the glycation level of γ2 subunit and function of AMPK and alternation of pathologies.

RESULTS

The glycation level of γ2 subunit was significantly elevated in 3 × Tg mice as compared with control mice, meanwhile, the level of pT172-AMPK was obviously lower in 3 × Tg mice than that in control mice. Moreover, we found that arginine protects the γ2 subunit of AMPK from glycation, preserves AMPK function, and improves pathologies and cognitive deficits in 3 × Tg mice.

CONCLUSIONS

Arginine treatment decreases glycated γ2 subunit of AMPK and increases p-AMPK levels in 3 × Tg mice, suggesting that reduced glycation of the γ2 subunit could ameliorate AMPK function and become a new target for AD therapy in the future.

The regulatory role of Gnao1 protein in diabetic encephalopathy in KK-Ay mice and streptozotocin-induced diabetic rats

AIMS

To investigate the regulation and functional role of Gnao1 in the brain of diabetic encephalopathy (DE) in various animal models.

RESULTS

Data from the biochemical and behavioral studies showed that DE models were successful induced in streptozotocin treatment animals and KK-Ay mice. Gnao1 was down regulated in the brain tissues of these two diabetes animal models with significant cognition deficiency. It suggested that the changes in DE are also related to dementia such as Alzheimer's disease (AD). Our study also showed that the expression of adrenergic α2 receptor (Adr-α2R), the upstream protein of Gnao1, was decreased in DE animal models. Furthermore, many downstream proteins of Gnao1 also altered, among which cAMP and PKA proteins were increased, CREB and BDNF proteins were decreased both in animal models and in the cell levels. In addition, Gnao1 silencing leads to the increase of reactive oxygen species (ROS) and the decreased proliferation in cultured primary astrocytes, which means that the deficiency of Gnao1 might not be benefit for DE.

CONCLUSION

Our findings demonstrated the importance of Gnao1 in DE and suggested Gnao1 as a novel marker and a promising therapeutic target for DE and dementia in animal models.

Metformin use is associated with a reduced risk of cognitive impairment in adults with diabetes mellitus: A systematic review and meta-analysis

Objective

Controversy exists regarding the impact of metformin and whether it prevents or promotes the incidence of cognitive dysfunction. This systematic review and meta-analysis were conducted to identify the effect of metformin therapy on cognitive function in patients with diabetes.

Methods

Electronic databases (PubMed, EMBASE, PsycINFO, the Cochrane Library, and Web of Science) were systematically searched by two investigators from the date of inception until March 1, 2022. The study followed PRISMA guidelines. Inclusion criteria were defined according to the PECOSmodel. Eligible studies investigated cognitive dysfunction in metformin users compared with non-users in adults with diabetes. Only observational study designs (such as cohort, cross-section, and case-control) were included.

Results

A systematic search identified 1,839 articles, of which 28 (17 cohort, 8 case-control, and 3 cross-sectional studies) were included in the meta-analysis. Metformin reduced the occurrence of cognitive impairment in patients with diabetes [unadjusted hazard ratio (HR) = 0.67, 95% CI: 0.62–0.73; adjusted hazard ratio (aHR) = 0.92, 95% CI: 0.85–0.99]. In addition, the use of metformin was associated with a decreased risk of dementia (HR = 0.64, 95% CI: 0.59–0.69; aHR = 0.90, 95% CI: 0.84–0.96), while a random-effects meta-analysis indicated no significant effect of metformin on the risk of Alzheimer's disease (AD) (HR = 0.85, 95% CI: 0.60–1.22; aHR = 1.10, 95% CI: 0.95–1.28).

Conclusion

Metformin therapy decreased the occurrence risk of cognitive decline in patients with diabetes mellitus. Moreover, the use of metformin by adults with diabetes for the prevention of dementia, but not AD, is supported by the available evidence.

LncRNA-MEG3 attenuates hyperglycemia-induced damage by enhancing mitochondrial translocation of HSP90A in the primary hippocampal neurons

The diabetic cognitive impairments are associated with high-glucose (HG)-induced mitochondrial dysfunctions in the brain. Our previous studies demonstrated that long non-coding RNA (lncRNA)-MEG3 alleviates diabetic cognitive impairments. However, the underlying mechanism has still remained elusive. Therefore, this study was designed to investigate whether the mitochondrial translocation of HSP90A and its phosphorylation are involved in lncRNA-MEG3-mediated neuroprotective effects of mitochondrial functions in HG-treated primary hippocampal neurons and diabetic rats. The primary hippocampal neurons were exposed to 75 mM glucose for 72 h to establish a HG model in vitro. Firstly, the RNA pull-down and RNA immunoprecipitation (RIP) assays clearly indicated that lncRNA-MEG3-associated mitochondrial proteins were Annexin A2, HSP90A, and Plectin. Although HG promoted the mitochondrial translocation of HSP90A and Annexin A2, lncRNA-MEG3 over-expression only enhanced the mitochondrial translocation of HSP90A, rather than Annexin A2, in the primary hippocampal neurons treated with or without HG. Meanwhile, Plectin mediated the mitochondrial localization of lncRNA-MEG3 and HSP90A. Furthermore, HSP90A threonine phosphorylation participated in regulating mitochondrial translocation of HSP90A, and lncRNA-MEG3 also enhanced mitochondrial translocation of HSP90A through suppressing HSP90A threonine phosphorylation. Finally, the anti-apoptotic role of mitochondrial translocation of HSP90A was found to be associated with inhibiting death receptor 5 (DR5) in HG-treated primary hippocampal neurons and diabetic rats. Taken together, lncRNA-MEG3 could improve mitochondrial functions in HG-exposed primary hippocampal neurons, and the underlying mechanisms were involved in enhanced mitochondrial translocation of HSP90A via suppressing HSP90A threonine phosphorylation, which may reveal a potential therapeutic target for diabetic cognitive impairments.

New Insights on the Regulation of the Insulin-Degrading Enzyme: Role of microRNAs and RBPs

The evident implication of the insulin-degrading enzyme (IDE) in Alzheimer’s disease (AD) and type 2 diabetes mellitus (T2DM), among its capacity to degrade insulin and amyloid-β peptide (Aβ), suggests that IDE could be an essential link in the relation between hyperinsulinemia, insulin resistance and AD. However, little is known about the cellular and molecular regulation of IDE expression, and even less has been explored regarding the post-transcriptional regulation of IDE, although it represents a great molecular target of interest for therapeutic treatments. We recently described that miR-7, a novel candidate for linking AD and T2DM at the molecular level, regulates IDE and other key genes in both pathologies, including some key genes involved in the insulin signaling pathway. Here, we explored whether other miRNAs as well as other post-transcriptional regulators, such as RNA binding proteins (RBP), could potentially participate in the regulation of IDE expression in vitro. Our data showed that in addition to miR-7, miR-125, miR-490 and miR-199 regulate IDE expression at the post-transcriptional level. Moreover, we also found that IDE contains multiple potential binding sites for several RBPs, and a narrow-down prediction analysis led us to speculate on a novel regulation of IDE by RALY and HuD. Taken together, these results demonstrate the novel players controlling IDE expression that could represent potential therapeutical targets to treat several metabolic diseases with a high impact on human health, including AD and T2DM.

Epigenetic regulation of synaptic disorder in Alzheimer’s disease

Synapses are critical structures involved in neurotransmission and neuroplasticity. Their activity depends on their complete structure and function, which are the basis of learning, memory, and cognitive function. Alzheimer’s disease (AD) is neuropathologically characterized by synaptic loss, synaptic disorder, and plasticity impairment. AD pathogenesis is characterized by complex interactions between genetic and environmental factors. Changes in various receptors on the postsynaptic membrane, synaptic components, and dendritic spines lead to synaptic disorder. Changes in epigenetic regulation, including DNA methylation, RNA interference, and histone modification, are closely related to AD. These can affect neuronal and synaptic functions by regulating the structure and expression of neuronal genes. Some drugs have ameliorated synaptic and neural dysfunction in AD models via epigenetic regulation. We reviewed the recent progress on pathological changes and epigenetic mechanisms of synaptic dysregulation in AD to provide a new perspective on this disease.

Emerging Pathophysiological Mechanisms Linking Diabetes Mellitus and Alzheimer’s Disease: An Old Wine in a New Bottle

Type-2 diabetes mellitus (T2DM) is a chronic immuno-inflammatory and metabolic disease characterized by hyperglycemia and insulin resistance with corresponding hyperinsulinemia. On the other hand, Alzheimer’s disease (AD) is a neurodegenerative disease involving cognitive impairment, neuronal dysfunction, and memory loss. Several recently published literatures suggest a causal relationship between T2DM and AD. In this review, we have discussed several potential mechanisms underlying diabetes-induced cognitive impairment which include, abnormal insulin signaling, amyloid-β accumulation, oxidative stress, immuno-inflammation, mitochondrial dysfunction, advanced glycation end products, acetylcholinesterase and butyrylcholinesterase, advanced lipid peroxidation products, and apolipoprotein E. All these interconnected mechanisms may act either individually or synergistically which eventually leads to neurodegeneration and AD.

Dietary polyphenols: regulate the advanced glycation end products-RAGE axis and the microbiota-gut-brain axis to prevent neurodegenerative diseases

Advanced glycation end products (AGEs) are formed in non-enzymatic reaction, oxidation, rearrangement and cross-linking between the active carbonyl groups of reducing sugars and the free amines of amino acids. The Maillard reaction is related to sensory characteristics in thermal processed food, while AGEs are formed in food matrix in this process. AGEs are a key link between carbonyl stress and neurodegenerative disease. AGEs can interact with receptors for AGEs (RAGE), causing oxidative stress, inflammation response and signal pathways activation related to neurodegenerative diseases. Neurodegenerative diseases are closely related to gut microbiota imbalance and intestinal inflammation. Polyphenols with multiple hydroxyl groups showed a powerful ability to scavenge ROS and capture α-dicarbonyl species, which led to the formation of mono- and di- adducts, thereby inhibiting AGEs formation. Neurodegenerative diseases can be effectively prevented by inhibiting AGEs production, and interaction with RAGEs, or regulating the microbiota-gut-brain axis. These strategies include polyphenols multifunctional effects on AGEs inhibition, RAGE-ligand interactions blocking, and regulating the abundance and diversity of gut microbiota, and intestinal inflammation alleviation to delay or prevent neurodegenerative diseases progress. It is a wise and promising strategy to supplement dietary polyphenols for preventing neurodegenerative diseases via AGEs-RAGE axis and microbiota-gut-brain axis regulation.

Posttranscriptional Regulation of Insulin Resistance: Implications for Metabolic Diseases

Insulin resistance defines an impairment in the biologic response to insulin action in target tissues, primarily the liver, muscle, adipose tissue, and brain. Insulin resistance affects physiology in many ways, causing hyperglycemia, hypertension, dyslipidemia, visceral adiposity, hyperinsulinemia, elevated inflammatory markers, and endothelial dysfunction, and its persistence leads to the development metabolic disease, including diabetes, obesity, cardiovascular disease, or nonalcoholic fatty liver disease (NAFLD), as well as neurological disorders such as Alzheimer’s disease. In addition to classical transcriptional factors, posttranscriptional control of gene expression exerted by microRNAs and RNA-binding proteins constitutes a new level of regulation with important implications in metabolic homeostasis. In this review, we describe miRNAs and RBPs that control key genes involved in the insulin signaling pathway and related regulatory networks, and their impact on human metabolic diseases at the molecular level, as well as their potential use for diagnosis and future therapeutics.

A Study of the Protective Effect of Bushen Huoxue Prescription on Cerebral Microvascular Endothelia Based on Proteomics and Bioinformatics

Diabetic cognitive dysfunction is a serious complication of type 2 diabetes mellitus (T2DM), which can cause neurological and microvascular damage in the brain. At present, there is no effective treatment for this complication. Bushen Huoxue prescription (BSHX) is a newly formulated compound Chinese medicine containing 7 components. Previous research indicated that BSHX was neuroprotective against advanced glycosylation end product (AGE)-induced PC12 cell insult; however, the effect of BSHX on AGE-induced cerebral microvascular endothelia injury has not been studied. In the current research, we investigated the protective effects of BSHX on AGE-induced injury in bEnd.3 cells. Our findings revealed that BSHX could effectively protect bEnd.3 cells from apoptosis. Moreover, we analyzed the network regulation effect of BSHX on AGE-induced bEnd.3 cells injury at the proteomic level. The LC-MS/MS-based shotgun proteomics analysis showed BSHX negatively regulated multiple AGE-elicited proteins. Bioinformatics analysis revealed these differential proteins were involved in multiple processes, such as Foxo signaling pathway. Further molecular biology analysis confirmed that BSHX could downregulate the expression of FoxO1/3 protein and inhibit its nuclear transfer and inhibit the expression of downstream apoptotic protein Bim and the activation of caspase, so as to play a protective role in AGE-induced bEnd.3 injury. Taken together, these findings demonstrated the role of BSHX in the management of diabetic cerebral microangiopathy and provide some insights into the proteomics-guided pharmacological mechanism study of traditional Chinese Medicine.

Identification of Flavonoid C-Glycosides as Promising Antidiabetics Targeting Protein Tyrosine Phosphatase 1B

Protein tyrosine phosphatase 1B (PTP1B), a negative regulator of the insulin signaling pathway, has gained attention as a validated druggable target in the management of type 2 diabetes mellitus (T2DM). The lack of clinically approved PTP1B inhibitors has continued to prompt research in plant-derived therapeutics possibly due to their relatively lesser toxicity profiles. Flavonoid C-glycosides are one of the plant-derived metabolites gaining increased relevance as antidiabetic agents, but their possible mechanism of action remains largely unknown. This study investigates the antidiabetic potential of flavonoid C-glycosides against PTP1B in silico and in vitro. Of the seven flavonoid C-glycosides docked against the enzyme, three compounds (apigenin, vitexin, and orientin) had the best affinity for the enzyme with a binding score of -7.3 kcal/mol each, relative to -7.4 kcal/mol for the reference standard, ursolic acid. A further probe (in terms of stability, flexibility, and compactness) of the complexes over a molecular dynamics time study of 100 ns for the three compounds suggested orientin as the most outstanding inhibitor of PTP1B owing to its overall -34.47 kcal/mol binding energy score compared to ursolic acid (-19.24 kcal/mol). This observation was in accordance with the in vitro evaluation result, where orientin had a half maximal inhibitory concentration (IC₅₀) of 0.18 mg/ml relative to 0.13 mg/ml for the reference standard. The kinetics of inhibition of PTP1B by orientin was mixed-type with V _max and K _m values of 0.004 μM/s and 0.515 μM. Put together, the results suggest orientin as a potential PTP1B inhibitor and could therefore be further explored in the management T2DM as a promising therapeutic agent.

Sleeve gastrectomy attenuated diabetes-related cognitive decline in diabetic rats

OBJECTIVE

To investigate the effects of sleeve gastrectomy (SG) on diabetes-related cognitive decline (DCD) in rats with diabetic mellitus (DM).

METHODS AND METHODS

Forty Wistar rats were randomly divided into control (CON) group (n=10), diabetes mellitus (DM) group (n=10), sham operation (SHAM) group (n=10) and SG group (n=10). DM model was established by high-fat diet (HFD) combined with intraperitoneal injection of streptozocin (STZ). Behavioral evaluation was given using Morris water maze test and Y-maze. In addition, PET-CT, TUNEL assay, histological analysis, transmission electron microscopy (TEM), immunohistochemistry (IHC) and Western blot analysis were used to evaluate the alleviating effects and potential mechanisms of SG on DCD in DM rats.

RESULTS

Compared with the sham group, SG induced significant improvement in the metabolic indices such as blood glucose and body weight. Besides, it could attenuate the insulin resistance compared with SHAM group. In addition, SG could improve the cognitive function of DM rats, which were featured by significant decrease in the escape latency (P<0.05), and significant increase in the time in target quadrant and platform crossings (P<0.05) compared with the SHAM group. SG induced significant elevation in the spontaneous alternation compared with SHAM group (P<0.05). Moreover, SG could improve the arrangement and biosynthesis of hippocampus neuron. Moreover, SG triggered the inhibition of apoptosis of hippocampus neurons, and Western blot analysis showed SG induced significant increase in the ratios of Bcl-2/Bax and Caspase3/cleaved Caspase 3. TEM demonstrated SG could significantly improve the microstructure of hippocampus neurons compared with the SHAM group. Western blot and IHC confirmed the significant decrease in the phosphorylation of tau at Ser404 and Ser396 sites in the SG group. Furthermore, SG activated the PI3K signaling pathway by elevating the phosphorylation of PI3K and Akt and GSK3β compared with the SHAM group.

CONCLUSION

SG attenuated the DCD in DM rats, which may be related to the activation of PI3K signaling pathway.

Serum levels of 4-hydroxynonenal adducts and responding autoantibodies correlate with the pathogenesis from hyperglycemia to Alzheimer's disease

OBJECTIVE

Hyperglycemia leads to lipid peroxidation, producing 4-hydroxynonenal (HNE) adducts which correlate with the production of amyloid-beta (Aβ), one of the hallmarks of Alzheimer's disease (AD). This study is to investigate the interactions of Aβ, HNE adducts and responding autoantibodies during the pathogenesis from hyperglycemia to AD.

METHODS

A total of 239 Taiwanese serum samples from a healthy control group and patients with hyperglycemia, and AD with and without hyperglycemia were analyzed. Aβ was immunoprecipitated from randomly pooled serum in each group and immunoblotted. Synthetic Aβ_1-16 and Aβ_17-28 peptides were modified with HNE in vitro and verified with LC-MS/MS. The levels of Aβ, HNE adducts, and autoantibody isotypes IgG and IgM against either native or HNE-modified Aβ were determined with ELISA. The diagnostic power of potential biomarkers was evaluated.

RESULTS

Increased fasting glucose and decreased high-density-lipoprotein cholesterol in AD groups indicated abnormal metabolism in the pathogenesis progression from hyperglycemia to AD. Indeed, serum Aβ, HNE adducts and most of the autoantibodies recognizing either native or HNE-modified Aβ were increased in the diseased groups. However, HNE adducts had better diagnostic performances than Aβ for both hyperglycemia and AD. Additionally, HNE-Aβ peptide levels were increased, and the responding autoantibodies (most notably IgM) were decreased in hyperglycemic AD group compared to the hyperglycemia only group, suggesting an immunity disturbance in the pathogenesis progression from hyperglycemia to AD.

CONCLUSION

Hyperglycemia increases the level of HNE adducts which may be neutralized by responding autoantibodies. Depletion of these autoantibodies promotes AD-like pathogenesis. Thus, levels of a patient's HNE adducts and associated responding autoantibodies are potential biomarkers for AD with diabetes.

Downregulation of Circular RNA PSEN1 ameliorates ferroptosis of the high glucose treated retinal pigment epithelial cells via miR-200b-3p/cofilin-2 axis

Ferroptosis is a form of programmed cell death that participates in the progression of numerous diseases. Long noncoding RNAs (lncRNAs) are dysregulated in diabetic retinopathy (DR). However, the role of lncRNAs in DR-induced ferroptosis is unclear. Adult retinal pigment epithelial cell line-19 (ARPE19) cells were treated with a high concentration of glucose (high glucose, HG) to mimic DR in vitro. The intracellular contents of glutathione, malondialdehyde, and ferrous ions were analyzed using the corresponding kits. The MTT assay was performed to measure the cell survival rate, and cell death was determined using propidium iodide and terminal deoxynucleotidyl transferase dUTP nick end labeling staining assays. Western blotting was conducted to detect the protein levels of GPX4, SLC7A11, and TFR1. The targeting relationships were verified using luciferase reporter and RNA pull-down assays. circ-PSEN1 was upregulated in HG-treated ARPE19 cells and showed high resistance to RNase R and Act D. Inhibition of circ-PSEN1 in ARPE19 cells ameliorated the ferroptosis induced by HG was ameliorated, as evidenced by changes in the ferroptosis-related biomarkers/genes and decreased cell death. Subsequently, circ-PSEN1 acted as a sponge for miR-200b-3p. Inhibition of miR-200b-3p partially reversed the effects of circ-PSEN1 on ferroptosis. Furthermore, cofilin-2 (CFL2) was the target gene of miR-200b-3p, and it abrogated the inhibitory effect of miR-200b-3p on ferroptosis. Taken together, the findings indicate that knockdown of circ-PSEN1 can mitigate ferroptosis of ARPE19 cells induced by HG via the miR-200b-3p/CFL2 axis.

Multimodal brain imaging effect of "Adjust Zang-fu and Arouse Spirit" electroacupuncture on diabetic cognitive impairment: study protocol of a randomized, sham-controlled pilot trial

BACKGROUND

Diabetic cognitive impairment (DCI) is a serious chronic complication caused by diabetes. The pathogenesis of DCI is complex, but brain nerve injury and brain nerve cell apoptosis are important pathological changes. Multimodal brain imaging is one of the most important techniques to study the neural mechanism of the brain. For the clinical treatment of DCI, there is no effective targeted Western medicine and a lack of clear drug intervention methods. Therefore, there is an urgent need to find effective complementary and alternative methods and clarify their mechanism. This research seeks to explore the multimodal brain imaging effect of "Adjust Zang-fu and Arouse Spirit" electroacupuncture for DCI.

METHODS

This clinical research will be a randomized, sham-controlled pilot trial. Eligible participants will be randomly assigned to the intervention group (n = 60) and the control group (n = 30). The intervention group will be divided into the "Adjust Zang-fu and Arouse Spirit" electroacupuncture group (n = 30) and sham electroacupuncture group (n = 30). All participants will continue to receive routine hypoglycemic therapy. The treatment period is the same in both groups. The primary outcomes include functional magnetic resonance imaging (fMRI), magnetic resonance spectroscopy (MRS), Montreal Cognitive Assessment Scale (MoCA), and Clinical Dementia Rating (CDR). The secondary outcomes include blood glucose and blood lipid tests, Instrumental Activities of Daily Living Scale (IADL), Hachinski Ischemic Scale (HIS), Self-Rating Anxiety Scale (SAS), and Self-Rating Depression Scale (SDS). Outcomes will be assessed at baseline and before and after treatment, and adverse events will be examined. Inter- and intragroup analyses will be performed.

DISCUSSION

This randomized controlled study, combined with multimodal brain imaging techniques and a clinical evaluation scale, was designed to explore the mechanism of "Adjust Zang-fu and Arouse Spirit" electroacupuncture in improving the central nervous system in DCI.

TRIAL REGISTRATION

Chinese Clinical Trial Registration ChiCTR2000040268 . Registered on 26 November 2020.

The role of traditional Chinese medicine in the treatment of cognitive dysfunction in type 2 diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic cognitive dysfunction (DCD) is mainly one of the complications of type 2 diabetes mellitus (T2DM) with complex and obscure pathogenesis. Extensive evidence has demonstrated the effectiveness and safety of traditional Chinese medicine (TCM) for DCD management.

AIM OF THE STUDY

This review attempted to systematically summarize the possible pathogenesis of DCD and the current Chinese medicine on the treatment of DCD.

MATERIALS AND METHODS

We acquired information of TCM on DCD treatment from PubMed, Web of Science, Science Direct and CNKI databases. We then dissected the potential mechanisms of currently reported TCMs and their active ingredients for the treatment of DCD by discussing the deficiencies and giving further recommendations.

RESULTS

Most TCMs and their active ingredients could improve DCD through alleviating insulin resistance, microvascular dysfunction, abnormal gut microbiota composition, inflammation, and the damages of the blood-brain barrier, cerebrovascular and neurons under hyperglycemia conditions.

CONCLUSIONS

TCM is effective in the treatment of DCD with few adverse reactions. A large number of in vivo and in vitro, and clinical trials are still needed to further reveal the potential quality markers of TCM on DCD treatment.

Genetic mutations of APOEε4 carriers in cardiovascular patients lead to the development of insulin resistance and risk of Alzheimer's disease

Type 2 diabetes mellitus and Alzheimer's disease (AD), both are chronic and progressive diseases. Many cardiovascular and genetic risk factors are considered responsible for the development of AD and diabetes mellitus (DM). Genetic risk factor such as apolipoprotein E (APOE) plays a critical role in the progression of AD. Specifically, APOEε4 is genetically the strongest isoform associated with neuronal insulin deficiency, altered lipid homeostasis, and metabolism, decreased glucose uptake, impaired gray matter volume, and cerebrovascular functions. In this article, we have summarized the mechanisms of cardiovascular disturbances associated with AD and DM, impact of amyloid-β aggregation, and neurofibrillary tangles formation in AD. Moreover, cardiovascular risk factors leading to insulin resistance (IR) and amyloid-β aggregation are highlighted along with the effects of APOE risk alleles on cerebral, lipid, and cholesterol metabolism leading to CVD-mediated IR. Correspondingly, the contribution of IR, genetic and cardiovascular risk factors in amyloid-β aggregation, which may lead to the late onset of AD and DM, has been also discussed. In short, IR is related to significantly lower cerebral glucose metabolism, which sequentially forecasts poorer memory performance. Hence, there will be more chances for neural glucose intolerance and impairment of cognitive function in cardiac patients, particularly APOEε4 carriers having IR. Hence, this review provides a better understanding of the corresponding crosstalk among different pathways. This will help to investigate the rational application of preventive measures against IR and cognitive dysfunction, specifically in APOEε4 carriers' cardio-metabolic patients.

Effect of Acupuncture on Cognitive Function of Insomnia Patients Compared with Drugs: A Protocol for Meta-analysis and Systematic Review

Insomnia, one of the most common sleep disorders, is thought to have an adverse effect on cognitive function. At the same time, people with cognitive dysfunction are more prone to insomnia. At present, pharmacotherapy is the main treatment for insomnia, but there are some shortcomings such as poor long-term efficacy and potential dependence. There is some evidence that acupuncture has some advantages in alleviating insomnia and improving cognitive function. This study is aimed at investigating the effects of acupuncture and drugs on cognitive function in patients with insomnia and evaluating the efficacy and safety of these two interventions, providing strong evidence for clinical decision-making. The study will retrieve eight major databases: China National Knowledge Infrastructure, Wanfang Database, VIP Database for Chinese Technical Periodicals, SinoMed, PubMed, Web of Science, Embase, and Cochrane Library. Dissertations, conference papers, and ongoing experiments will also be retrieved for supplement. Literature screening and data extraction will be completed by two authors independently (JJ and X-QW). If there were any disagreements, they would be discussed or referred to a third person for adjudication (W-ZW). Authors will use Cochrane risk of bias tool to assess the included studies. The Review Manager Statistical (RevMan) software is used to conduct the statistical process of meta-analysis, and funnel plot is used to evaluate reporting biases. The Grading of Recommendations Assessment Development and Evaluation (GRADE) Profiler can be used to be aware of the quality of evidence.

ZiBuPiYin Recipe Prevented and Treated Cognitive Decline in ZDF Rats With Diabetes-Associated Cognitive Decline via Microbiota-Gut-Brain Axis Dialogue

Gut microbiota is becoming one of the key determinants in human health and disease. Shifts in gut microbiota composition affect cognitive function and provide new insights for the prevention and treatment of neurological diseases. Diabetes-associated cognitive decline (DACD) is one of the central nervous system complications of type 2 diabetes mellitus (T2DM). ZiBuPiYin recipe (ZBPYR), a traditional Chinese medicine (TCM) formula, has long been used for the treatment of T2DM and prevention of DACD. However, the contribution of ZBPYR treatment to the interaction between the gut microbiota and metabolism for preventing and treating DACD remains to be clarified. Here, we investigate whether the gut microbiota plays a key role in ZBPYR-mediated prevention of DACD and treatment of T2DM via incorporating microbiomics and metabolomics, and investigate the links between the microbiota-gut-brain axis interaction and the efficacy of ZBPYR in ZDF rats. In the current study, we found that ZBPYR treatment produced lasting changes in gut microbiota community and metabolites and remotely affected hippocampus metabolic changes, thereby improving memory deficits and reversing β-amyloid deposition and insulin resistance in the brain of ZDF rats from T2DM to DACD. This may be related to a series of metabolic changes affected by gut microbiota, including alanine, aspartic acid, and glutamic acid metabolism; branched-chain amino acid metabolism; short-chain fatty acid metabolism; and linoleic acid/unsaturated fatty acid metabolism. In summary, this study demonstrates that prevention and treatment of DACD by ZBPYR partly depends on the gut microbiota, and the regulatory effects of bacteria-derived metabolites and microbiota-gut-brain axis are important protective mechanisms of ZBPYR.

Oleic Acid and Insulin as Key Characteristics of T2D Promote Colorectal Cancer Deterioration in Xenograft Mice Revealed by Functional Metabolomics

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers with high mortality worldwide. Type 2 diabetes mellitus (T2D), known as a risk factor of CRC, can promote the deterioration of CRC, but the underlying mechanism is elusive. In this study, we aimed to reveal the relationship between CRC and T2D from the perspective of small-molecule metabolism. First, a list of common dysregulated metabolites in CRC and T2D was obtained by retrieving existing metabolomics publications. Among these metabolites, oleic acid (OA) was found to be able to promote the proliferation and migration of colon carcinoma cell HCT116. Further experiments proved that insulin could significantly strengthen this promotion and showed a synergistic effect with OA. Mechanism study found that OA and insulin acted synergistically through the extracellular signal-regulated kinase (ERK)1/2/c-Myc/cyclin D1 pathway. In addition, the combination of ERK1/2 inhibitor SCH772984 and cyclin-dependent kinase (CDK)4/6 inhibitor palbociclib showed a remarkable inhibitory effect on tumor growth in vivo. Taken together, the current study found that OA plays an important role in CRC development by using a functional metabolomics approach. More importantly, insulin and OA were confirmed to synergistically promote the deterioration of CRC in vitro and in vivo via ERK1/2/c-Myc/cyclin D1 pathway. Our findings may shed light on CRC treatment among the T2D population.

Hydroxytyrosol Selectively Affects Non-Enzymatic Glycation in Human Insulin and Protects by AGEs Cytotoxicity

Hydroxytyrosol (HT), the major phenolic compound in olive oil, is attracting increasing interest for its beneficial properties including a notable antioxidant and anti-inflammatory power. In this study, using a combination of biophysical and cell biology techniques, we have tested the role of HT in the formation of advanced glycation end-products (AGEs). AGEs have a key role in clinical sciences as they have been associated to diabetes, neurodegenerative and cardiovascular diseases. In addition, as the incidence of Alzheimer’s disease (AD) is strongly increased in diabetic patients, AGE formation is supposed to be involved in the development of the pathological hallmarks of AD. Our data show that HT selectively inhibits protein glycation reaction in human insulin, and it is able to counteract the AGE-induced cytotoxicity in human neurotypical cells by acting on SIRT1 level and oxidative stress, as well as on inflammatory response. This study identifies new beneficial properties for HT and suggests it might be a promising molecule in protecting against the AGE-induced toxicity, a key mechanism underlying the development and progression of neurodegenerative disorders.

Estrogenic Plants: to Prevent Neurodegeneration and Memory Loss and Other Symptoms in Women After Menopause

In mammals, sexual hormones such as estrogens play an essential role in maintaining brain homeostasis and function. Estrogen deficit in the brain induces many undesirable symptoms such as learning and memory impairment, sleep and mood disorders, hot flushes, and fatigue. These symptoms are frequent in women who reached menopausal age or have had ovariectomy and in men and women subjected to anti-estrogen therapy. Hormone replacement therapy alleviates menopause symptoms; however, it can increase cardiovascular and cancer diseases. In the search for therapeutic alternatives, medicinal plants and specific synthetic and natural molecules with estrogenic effects have attracted widespread attention between the public and the scientific community. Various plants have been used for centuries to alleviate menstrual and menopause symptoms, such as Cranberry, Ginger, Hops, Milk Thistle, Red clover, Salvia officinalis, Soy, Black cohosh, Turnera diffusa, Ushuva, and Vitex. This review aims to highlight current evidence about estrogenic medicinal plants and their pharmacological effects on cognitive deficits induced by estrogen deficiency during menopause and aging.

Exercise as a Therapeutic Intervention in Gestational Diabetes Mellitus

Gestational Diabetes Mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition during pregnancy. Regular exercise is important for a healthy pregnancy and can lower the risk of developing GDM. For women with GDM, exercise is safe and can affect the pregnancy outcomes beneficially. A single exercise bout increases skeletal muscle glucose uptake, minimizing hyperglycemia. Regular exercise training promotes mitochondrial biogenesis, improves oxidative capacity, enhances insulin sensitivity and vascular function, and reduces systemic inflammation. Exercise may also aid in lowering the insulin dose in insulin-treated pregnant women. Despite these benefits, women with GDM are usually inactive or have poor participation in exercise training. Attractive individualized exercise programs that will increase adherence and result in optimal maternal and offspring benefits are needed. However, as women with GDM have a unique physiology, more attention is required during exercise prescription. This review (i) summarizes the cardiovascular and metabolic adaptations due to pregnancy and outlines the mechanisms through which exercise can improve glycemic control and overall health in insulin resistance states, (ii) presents the pathophysiological alterations induced by GDM that affect exercise responses, and (iii) highlights cardinal points of an exercise program for women with GDM.

Neuroprotective Effects of 2-Substituted 1, 3-Selenazole Amide Derivatives on Amyloid-Beta-Induced Toxicity in a Transgenic Caenorhabditis Elegans Model of Alzheimer's Disease

Alzheimer's disease is an age-related neurodegenerative disease, associated with the presence of extracellular amyloid-β (Aβ) plaques and neurofibrillary tangles. Although the pathogenesis of AD remains unclear, the characteristic feature of AD was reported to be the buildup of Aβ plaques. In this study, we extensively investigated the neuroprotective effects of 2-substituted 1,3-selenazole amide derivatives (CHF11) on Aβ1-42 transgenic Caenorhabditis elegans CL4176. Results showed that worms fed with CHF11 exhibited remarkably reduced paralysis, decreased levels of toxic Aβ oligomers and Aβ plaque deposition, as well as less ROS production in comparison with the untreated worms. The effective concentrations of CHF11 were arranged in the descending order of 100 µM > 10 µM > 1 µM. Real-time PCR analysis showed that there was no significant difference in Aβ expression between CHF11-administered group and the blank control group, suggesting that CHF11-induced reduction in toxic protein deposition may be regulated at the post-transcriptional level. In the meantime, the gene expressions of hsf-1 and its downstream target hsp-12.6 were significantly increased, indicating that CHF11 against Aβ toxicity may involve in HSF-1 signaling pathway in worms. In conclusion, CHF11 exhibits a significant protective effect against β-amyloid-induced toxicity in CL4176 by reducing β-amyloid aggregation and ROS production, which may involve in HSF-1 and downstream target HSP-12.6 pathway.

Hypertension and Age-Related Cognitive Impairment: Common Risk Factors and a Role for Precision Aging

Purpose of Review

Precision Aging® is a novel concept that we have recently employed to describe how the model of precision medicine can be used to understand and define the multivariate risks that drive age-related cognitive impairment (ARCI). Hypertension and cardiovascular disease are key risk factors for both brain function and cognitive aging. In this review, we will discuss the common mechanisms underlying the risk factors for both hypertension and ARCI and how the convergence of these mechanisms may be amplified in an individual to drive changes in brain health and accelerate cognitive decline.

Recent Findings

Currently, our cognitive health span does not match our life span. Age-related cognitive impairment and preventing and treating ARCI will require an in-depth understanding of the interrelated risk factors, including individual genetic profiles, that affect brain health and brain aging. Hypertension and cardiovascular disease are important risk factors for ARCI. And, many of the risk factors for developing hypertension, such as diabetes, smoking, stress, viral infection, and age, are shared with the development of ARCI. We must first understand the mechanisms common to the converging risk factors in hypertension and ARCI and then design person-specific therapies to optimize individual brain health.

Summary

The understanding of the convergence of shared risk factors between hypertension and ARCI is required to develop individualized interventions to optimize brain health across the life span. We will conclude with a discussion of possible steps that may be taken to decrease ARCI and optimize an individual’s cognitive life span.

Pathological Mechanisms Linking Diabetes Mellitus and Alzheimer's Disease: the Receptor for Advanced Glycation End Products (RAGE)

Diabetes and Alzheimer’s disease (AD) place a significant burden on health care systems in the world and its aging populations. These diseases have long been regarded as separate entities; however, advanced glycation end products (AGEs) and the receptors for AGEs (RAGE) may be a link between diabetes and AD. In our study, mice injected with AGEs through stereotaxic surgery showed significant AD-like features: behavior showed decreased memory; immunofluorescence showed increased phosphorylated tau and APP. These results suggest links between diabetes and AD. Patients with diabetes are at a higher risk of developing AD, and the possible underlying molecular components of this association are now beginning to emerge.

Modulation of MicroRNAs as a Potential Molecular Mechanism Involved in the Beneficial Actions of Physical Exercise in Alzheimer Disease

Alzheimer disease (AD) is one of the most common neurodegenerative diseases, affecting middle-aged and elderly individuals worldwide. AD pathophysiology involves the accumulation of beta-amyloid plaques and neurofibrillary tangles in the brain, along with chronic neuroinflammation and neurodegeneration. Physical exercise (PE) is a beneficial non-pharmacological strategy and has been described as an ally to combat cognitive decline in individuals with AD. However, the molecular mechanisms that govern the beneficial adaptations induced by PE in AD are not fully elucidated. MicroRNAs are small non-coding RNAs involved in the post-transcriptional regulation of gene expression, inhibiting or degrading their target mRNAs. MicroRNAs are involved in physiological processes that govern normal brain function and deregulated microRNA profiles are associated with the development and progression of AD. It is also known that PE changes microRNA expression profile in the circulation and in target tissues and organs. Thus, this review aimed to identify the role of deregulated microRNAs in the pathophysiology of AD and explore the possible role of the modulation of microRNAs as a molecular mechanism involved in the beneficial actions of PE in AD.