Glibenclamide mitigates cognitive impairment and hippocampal neuroinflammation in rats with type 2 diabetes and sporadic Alzheimer-like disease

The impact of ATP-sensitive potassium channel modulation on mitochondria in a Parkinson's disease model using SH-SY5Y cells depends on their differentiation state

Inward rectifying potassium channels sensitive to ATP levels (KATP) have been the subject of investigation for several decades. Modulators of KATP channels are well-established treatments for metabolic as well as cardiovascular diseases. Experimental studies have also shown the potential of KATP modulation in neurodegenerative disorders. However, to date, data regarding the effects of KATP antagonists/agonists in experiments related to neurodegeneration remain inconsistent. The main source of confusion in evaluating available data seems to be the choice of experimental models. The present study aims to provide a comprehensive understanding of the effects of both opening and blocking KATP channels in two forms of SH-SY5Y cells. Our results offer valuable insights into the significance of metabolic differences between differentiated and non-differentiated SH-SY5Y cells, particularly in the context of glibenclamide and diazoxide effects under normal conditions and during the initiation of pathological events simulating Parkinson's disease in vitro. We emphasize the analysis of mitochondrial functions and changes in mitochondrial network morphology. The heightened protein expression of KATP channels identified in non-differentiated SH-SY5Y cells seems to be a platform for a more significant impact of KATP modulators in this cell type. The efficiency of rotenone treatment in inducing morphological changes in the mitochondrial network depends on the differentiation status of SH-SY5Y cells.

Huang-Lian-Jie-Du decoction drug-containing serum inhibits IL-1β secretion from D-glucose and PA induced BV2 cells via autophagy/NLRP3 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Lian-Jie-Du decoction (HLJDD), a famous traditional Chinese medicine prescription with heat-clearing and detoxifying effects, has been widely used to treat diabetes, dementia, stroke, and other diseases. However, the detailed mechanisms of HLJDD against type 2 diabetes associated cognitive dysfunction (DACD) through inhibiting interleukin-1β (IL-1β) mediated neuroinflammation remain to be further elucidated.

AIM OF THE STUDY

The aim of this study was to investigate the effect and potential mechanism of HLJDD on IL-1β secretion in a DACD model of BV2 cells induced by D-glucose and palmitic acid (PA).

MATERIALS AND METHOD

sUltra-performance liquid chromatography-quadrupole/electrostatic field orbital well high-resolution mass spectrometry technology was used to analyze the compounds in HLJDD drug-containing serum. The cytotoxicity was detected by cell counting kit-8. Enzyme-linked immunosorbent assay was used to measure the secretion of IL-1β in BV2 cells. Reactive oxygen species, glutathione, superoxide dismutase, and malondialdehyde kits were used to detect the intracellular oxidative stress levels. The autophagy level was determined by autophagy staining kit and transmission electron microscope. The expression levels of autophagy-related 7 (Atg7), P62, LC3, nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3(NLRP3), Caspase1, and IL-1β were detected by real-time PCR, immunofluorescence, and western blotting. The Atg7siRNA was transfected into BV2 cells to produce autophagy inhibitory effect. Then the effect of HLJDD drug-containing serum on IL-1β secretion in D-glucose and PA induced BV2 cells and the potential mechanism of autophagy-NLRP3 inflammasome activation were further observed.

RESULTS

Eighty-eight compounds were preliminarily identified in HLJDD drug-containing serum, among which geniposide, baicalin, palmatine, berberine, wogonoside, wogonin, and geniposidic acid were identified as the main prototype components of HLJDD into the blood. In this study, the DACD model of BV2 cells induced by high concentrations of glucose and PA was successfully constructed. HLJDD drug-containing serum significantly reduced the secretion of IL-1β and the activity of NLRP3 inflammasome with improving the oxidative stress level. Interestingly, the enhanced autophagy level was also found. After transfection of Atg7siRNA into BV2 cells, the effect of HLJDD drug-containing serum on autophagy promotion was reversed, but the inhibitory effects on IL-1β secretion, NLRP3 inflammasome activation, and oxidative stress were reduced.

CONCLUSIONS

These results indicated that the inhibition of HLJDD drug-containing serum on the IL-1β secretion in D-glucose and PA induced BV2 cells was related to autophagy promotion, the decreased NLRP3 inflammasome activation, and the improved oxidative stress. Moreover, the improvement of HLJDD drug-containing serum on IL-1β secretion, NLRP3 inflammasome activation, and oxidative stress were all closely associated with Atg7 mediated autophagy promotion. Geniposide, baicalin, palmatine, berberine, wogonoside, wogonin, and geniposidic acid may be the potential active ingredients of HLJDD drug-containing serum.

The associations between type 2 diabetes and plasma biomarkers of Alzheimer's disease in the Health and Aging Brain Study: Health Disparities (HABS-HD)

Alzheimer's disease (AD) affects Latinos disproportionately. One of the reasons underlying this disparity may be type 2 diabetes (T2D) that is a risk factor for AD. The purpose of this study was to examine the associations of T2D and AD blood biomarkers and the differences in these associations between Mexican Americans and non-Hispanic Whites. This study was a secondary analysis of baseline data from the observational Health and Aging Brain Study: Health Disparities (HABS-HD) that investigated factors underlying health disparities in AD in Mexican Americans in comparison to non-Hispanic Whites. HABS-HD participants were excluded if they had missing data or were large outliers (z-scores >|4|) on a given AD biomarker. Fasting blood glucose and glycosylated hemoglobin (HbA1c) levels were measured from clinical labs. T2D was diagnosed by licensed clinicians. Plasma amyloid-beta 42 and 40 (Aβ42/42) ratio, total tau (t-tau), and neurofilament light (NfL) were measured via ultra-sensitive Simoa assays. The sample sizes were 1,552 for Aβ42/40 ratio, 1,570 for t-tau, and 1,553 for NfL. Mexican Americans were younger (66.6±8.7 vs. 69.5±8.6) and had more female (64.9% female vs. 55.1%) and fewer years of schooling (9.5±4.6 vs. 15.6±2.5) than non-Hispanic Whites. Mexican Americans differed significantly from non-Hispanic Whites in blood glucose (113.5±36.6 vs. 99.2±17.0) and HbA1c (6.33±1.4 vs. 5.51±0.6) levels, T2D diagnosis (35.3% vs. 11.1%), as well as blood Aβ42/40 ratio (.051±.012 vs. .047±.011), t-tau (2.56±.95 vs. 2.33±.90), and NfL levels (16.3±9.5 vs. 20.3±10.3). Blood glucose, blood HbA1c, and T2D diagnosis were not related to Aβ42/40 ratio and t-tau but explained 3.7% of the variation in NfL (p < .001). Blood glucose and T2D diagnosis were not, while HbA1c was positively (b = 2.31, p < .001, β = 0.26), associated with NfL among Mexican Americans. In contrast, blood glucose, HbA1c, and T2D diagnosis were negatively (b = -0.09, p < .01, β = -0.26), not (b = 0.34, p = .71, β = 0.04), and positively (b = 3.32, p < .01, β = 0.33) associated with NfL, respectively in non-Hispanic Whites. To conclude, blood glucose and HbA1c levels and T2D diagnosis are associated with plasma NfL levels, but not plasma Aβ and t-tau levels. These associations differ in an ethnicity-specific manner and need to be further studied as a potential mechanism underlying AD disparities.

Association of sulfonylureas with the risk of dementia: A population-based cohort study

BACKGROUND

Sulfonylureas are oral glucose-lowering medications positioned as a second-line therapy for type 2 diabetes. Evidence relating them to cognitive decline has been mixed. The objective was to determine whether sulfonylurea use was associated with a differential risk of dementia compared with dipeptidyl peptidase-4 (DPP4) inhibitor use.

METHODS

Using administrative data from residents in Ontario, Canada, adults aged ≥66 years who were new users of a sulfonylurea or a DPP4 inhibitor from June 14, 2011, to March 31, 2021 entered this population-based retrospective cohort study. Dementia was ascertained using a validated algorithm for Alzheimer's disease and related dementias. Propensity-score weighted Cox proportional hazards models were used to obtain adjusted hazard ratios (aHR) and confidence intervals (CI) for time to incident dementia. The observation window started at 1 year after cohort entry to mitigate protopathic bias due to delayed diagnosis. The primary analysis used an intention-to-treat exposure definition. A separate propensity-score weighted analysis was conducted to explore within-class differences in dementia risk among sulfonylurea new users selected from the primary cohort.

RESULTS

Among 107,806 DPP4 inhibitor new users and 37,030 sulfonylurea new users, sulfonylureas compared with DPP4 inhibitors were associated with a higher risk of dementia (18.4/1000 person-years; aHR [95% CI] = 1.09 [1.04-1.15]) over a mean follow-up of 4.82 years from cohort entry. Glyburide compared to gliclazide exhibited a higher dementia risk (aHR [95% CI] = 1.17 [1.03-1.32]).

CONCLUSION

New use of a sulfonylurea especially glyburide was associated with a higher dementia risk compared with new use of a DPP4 inhibitor in older adults with diabetes.

Physical activity in a swimming pool attenuates memory impairment by reducing glutamate and inflammatory cytokines and increasing BDNF in the brain of mice with type 2 diabetes

Type 2 diabetes is a risk factor for the development of cognitive impairment. Increasing evidence suggests that regular exercise is beneficial for the treatment of clinical symptoms in diabetic patients. The current study aimed to evaluate whether increasing physical activity through swimming training can reduce memory impairment in an animal model of type 2 diabetes. Diabetes and non-diabetes mice underwent swimming training for four weeks, and then working, spatial, and recognition memory were evaluated using three behavioral tests. Body weight, glucose, and insulin resistance were monitored. We also measured inflammatory cytokines (interleukin (IL)- 6, IL-1β, and tumor-necrosis-factor (TNF)-α), an anti-inflammatory cytokine (IL-10), and brain-derived-neurotrophic-factor (BDNF), and glutamate levels in the hippocampus or prefrontal cortex of mice. The findings showed that diabetes increased body weight, glucose, and insulin resistance, impaired working, spatial and recognition memory, increased levels of IL-6, IL-1β, TNF-α, and glutamate levels, and decreased BDNF in the hippocampus of diabetic mice. While higher physical activity was associated with reduced body weight, glucose, and insulin resistance, attenuated memory impairment, IL-6, IL-1β, TNF-α, and glutamate, and increased BDNF levels in the hippocampus and prefrontal cortex of diabetic mice. This study shows that swimming training can normalize body weight and glucose-insulin axis and reduce inflammation and glutamate in the hippocampus and enhance the neurotrophic system in both the hippocampus and prefrontal cortex of diabetic mice. This study also suggests that higher physical activity through swimming training can improve cognitive impairment in a mouse model of type 2 diabetes.

Repositioning of Anti-Diabetic Drugs against Dementia: Insight from Molecular Perspectives to Clinical Trials

Insulin resistance as a hallmark of type 2 DM (T2DM) plays a role in dementia by promoting pathological lesions or enhancing the vulnerability of the brain. Numerous studies related to insulin/insulin-like growth factor 1 (IGF-1) signaling are linked with various types of dementia. Brain insulin resistance in dementia is linked to disturbances in Aβ production and clearance, Tau hyperphosphorylation, microglial activation causing increased neuroinflammation, and the breakdown of tight junctions in the blood-brain barrier (BBB). These mechanisms have been studied primarily in Alzheimer's disease (AD), but research on other forms of dementia like vascular dementia (VaD), Lewy body dementia (LBD), and frontotemporal dementia (FTD) has also explored overlapping mechanisms. Researchers are currently trying to repurpose anti-diabetic drugs to treat dementia, which are dominated by insulin sensitizers and insulin substrates. Although it seems promising and feasible, none of the trials have succeeded in ameliorating cognitive decline in late-onset dementia. We highlight the possibility of repositioning anti-diabetic drugs as a strategy for dementia therapy by reflecting on current and previous clinical trials. We also describe the molecular perspectives of various types of dementia through the insulin/IGF-1 signaling pathway.

Adolescent swimming exercise following maternal valproic acid treatment improves cognition and reduces stress-related symptoms in offspring mice: Role of sex and brain cytokines

Valproic acid (VPA) treatment during pregnancy is a risk factor for developing autism spectrum disorder, cognitive deficits, and stress-related disorders in children. No effective therapeutic strategies are currently approved to treat or manage core symptoms of autism. Active lifestyles and physical activity are closely associated with health and quality of life during childhood and adulthood. This study aimed to evaluate whether swimming exercise during adolescence can prevent the development of cognitive dysfunction and stress-related disorders in prenatally VPA-exposed mice offspring. Pregnant mice received VPA, afterwards, offspring were subjected to swimming exercise. We assessed neurobehavioral performances and inflammatory cytokines (interleukin-(IL)6, tumor-necrosis-factor-(TNF)α, interferon-(IFN)γ, and IL-17A) in the hippocampus and prefrontal cortex of offspring. Prenatal VPA treatment increased anxiety-and anhedonia-like behavior and decreased social behavior in male and female offspring. Prenatal VPA exposure also increased behavioral despair and reduced working and recognition memory in male offspring. Although prenatal VPA increased hippocampal IL-6 and IFN-γ, and prefrontal IFN-γ and IL-17 in males, it only increased hippocampal TNF-α and IFN-γ in female offspring. Adolescent exercise made VPA-treated male and female offspring resistant to anxiety-and anhedonia-like behavior in adulthood, whereas it only made VPA-exposed male offspring resistant to behavioral despair, social and cognitive deficits in adulthood. Exercise reduced hippocampal IL-6, TNF-α, IFN-γ, and IL-17, and prefrontal IFN-γ and IL-17 in VPA-treated male offspring, whereas it reduced hippocampal TNF-α and IFN-γ in VPA-treated female offspring. This study suggests that adolescent exercise may prevents the development of stress-related symptoms, cognitive deficits, and neuroinflammation in prenatally VPA-exposed offspring mice.

Clinical antidiabetic medication used in Alzheimer's disease: From basic discovery to therapeutics development

Alzheimer's disease (AD) is a common neurodegenerative disease. Type 2 diabetes mellitus (T2DM) appears to increase and contributing to the risk of AD. Therefore, there is increasing concern about clinical antidiabetic medication used in AD. Most of them show some potential in basic research, but not in clinical research. So we reviewed the opportunities and challenges faced by some antidiabetic medication used in AD from basic to clinical research. Based on existing research progress, this is still the hope of some patients with special types of AD caused by rising blood glucose or/and insulin resistance.

Targeting of neuroinflammation by glibenclamide in Covid-19: old weapon from arsenal

In coronavirus disease 2019 (Covid-19) era, neuroinflammation may develop due to neuronal tropism of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) and/or associated immune activation, cytokine storm, and psychological stress. SARS-CoV-2 infection and linked cytokine storm may cause blood-brain barrier (BBB) injury through which activated immune cells and SARS-CoV-2 can pass into the brain causing activation of glial cells with subsequent neuroinflammation. Different therapeutic regimens were suggested to alleviate Covid-19-induced neuroinflammation. Since glibenclamide has anti-inflammatory and neuroprotective effects, it could be effective in mitigation of SARS-CoV-2 infection-induced neuroinflammation. Glibenclamide is a second-generation drug from the sulfonylurea family, which acts by inhibiting the adenosine triphosphate (ATP)-sensitive K channel in the regulatory subunit of type 1 sulfonylurea receptor (SUR-1) in pancreatic β cells. Glibenclamide reduces neuroinflammation and associated BBB injury by inhibiting the nod-like receptor pyrin 3 (NLRP3) inflammasome, oxidative stress, and microglial activation. Therefore, glibenclamide through inhibition of NLRP3 inflammasome, microglial activation, and oxidative stress may attenuate SARS-CoV-2-mediated neuroinflammation.

Hotspots and frontier trends of diabetic associated cognitive decline research based on rat and mouse models from 2012 to 2021: A bibliometric study

Background

The establishment of rodent models, such as rat and mouse models, plays a critical role in the study of diabetic associated cognitive decline. With the continuous growth of relevant literature information, it is difficult for researchers to accurately and timely capture the topics in this field. Therefore, this study aims to explore the current status and frontier trends of diabetic associated cognitive decline research based on rat and mouse models through a bibliometric analysis.

Methods

We collected 701 original articles on this subject from the Science Citation Index Expanded of the Web of Science Core Collection from 2012 to 2021. Then we utilized CiteSpace and VOSviewer for plotting knowledge maps and evaluating hotpots and trends.

Results

During this decade, except for a slight decline in 2020, the number of annual outputs on diabetes associated cognitive decline research using rat and mouse models increased every year. China (country), China Pharmaceutical University (institution), Gao, Hongchang (the author from the School of Pharmacy of Wenzhou Medical University, China), and Metabolic Brain Disease (journal) published the most papers in this research field. The analysis results of co-cited references and co-occurrence keywords indicated that "mechanisms and prevention and treatment methods", especially "oxidative stress", "potential association with Alzheimer's disease" and "spatial memory" are research focuses in this subject area. The bursts detection of references and keywords implied that "cognitive impairment of type 1 diabetes" and "autophagy and diabetes associated cognitive decline" will be potential directions for future research in this subject area.

Conclusion

This study systematically assessed general information, current status and emerging trends of diabetic associated cognitive decline research using rat and mouse models in the past decade based on a bibliometric analysis. The number of publications was annually increasing although a slight decline was observed in 2020. Contributions from different countries/regions, institutions, authors, co-cited authors, journals and co-cited journals were evaluated, which may also be used to guide future research. Through the analysis of references and keywords, we predicted the future research hotspots and trends in this field.

Glibenclamide as a neuroprotective antidementia drug

In the view of progressively aging human population and increased occurrence of dysmetabolic disorders, such as diabetes mellitus, cognitive impairment becomes a major threat to the national health. To date, the molecular mechanisms of cognitive dysfunction are partially described for diabetes and diseases of different nature, such as Alzheimer disease or Parkinson disease. The emergence of data pointing towards pleotropic effects of hypoglycaemic medicines indicates involvement of their targets in pathogenesis of cognitive impairment. We are aiming here to review available data on the most widely used hypoglycaemic drug, glibenclamide and find possible relationship of its targets to the pathogenesis of cognitive impairment.

Melatonin treatment improves cognitive deficits by altering inflammatory and neurotrophic factors in the hippocampus of obese mice

Overweight and obesity are associated with an increased risk of developing dementia and cognitive deficits. Neuroinflammation is one of the most important mechanisms behind cognitive impairment in obese patients. In recent years, the neuroendocrine hormone melatonin has been suggested to have therapeutic effects for memory decline in several neuropsychiatric and neurological conditions. However, the effects of melatonin on cognitive function under obesity conditions still need to be clarified. The purpose of this study was to determine whether melatonin treatment can improve cognitive impairment in obese mice. To this end, male C57BL6 mice were treated with a high-fat diet (HFD) for 20 weeks to induce obesity. The animal received melatonin for 8 weeks. Cognitive functions were evaluated using the Y maze, object recognition test, and the Morris water maze. We measured inflammatory cytokines including tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-17A, and brain-derived neurotrophic factor (BDNF) in the hippocampus of obese mice. Our results show that HFD-induced obesity significantly impaired working, spatial and recognition memory by increasing IFN-γ and IL-17A and decreasing BDNF levels in the hippocampus of mice. On the other hand, melatonin treatment effectively improved all cognitive impairments and reduced TNF-α, IFN-γ, and IL-17A and elevated BDNF levels in the hippocampus of obese mice. Taken together, this study suggests that melatonin treatment could have a beneficial role in the treatment of cognitive impairment in obesity.

Glibenclamide alters serotonin and dopamine levels in the rat striatum and hippocampus, reducing cognitive impairment

RATIONALE

Glibenclamide (GD) is a widely used medical drug; therefore, identifying the mechanisms underlying its pleiotropic effects in the central nervous system is urgent.

OBJECTIVES

The aim of this work was to determine the ability of GD to modulate serotonin (5-hydroxytryptamine, 5-HT) and dopamine (DA) transmission and to assess the dose-dependent effect of GD on cognitive function in rats during natural ageing.

METHODS

In Experiment 1, rats received 10, 25, or 50 μg/kg GD intraperitoneally for 10 days. In Experiment 2, rats received 50 μg/kg GD intraperitoneally for 30 days. Spatial and working memory was assessed in the MWM and Y-maze tests, respectively. In both experiments, the levels of DA and 5-HT, their metabolites, and turnover rate were analysed by HPLC-ED in the rat hippocampus and striatum.

RESULTS

Changes in DA and 5-HT levels occurred only with a dose of 50 μg/kg GD. Therefore, in the second experiment, we administered a dose of 50 μg/kg GD. At this dose, GD prevented the development of impairments in spatial and working memory. The hippocampal concentrations of DA and DOPAC decreased, and the striatal concentrations of DA, DOPAC, 5-HT, and 5-HIAA increased.

CONCLUSION

One of the possible mechanisms of the precognitive effect of GD is its ability to modulate monoamine transmission. Thus, in translating our results to humans, GD can be recommended as a prophylactic agent for natural ageing to reduce the risk of developing cognitive impairments.

Huang-Lian-Jie-Du decoction attenuates cognitive dysfunction of rats with type 2 diabetes by regulating autophagy and NLRP3 inflammasome activation

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Lian-Jie-Du decoction (HLJDD) is a traditional Chinese formula that is efficacious in treating diabetes mellitus, Alzheimer's disease, and diabetic encephalopathy; the underlying mechanisms of HLJDD in diabetes-associated cognitive dysfunction remain unclear.

AIM OF THE STUDY

This study investigated the neuroprotective effects of HLJDD on cognitive function, and the possible underlying mechanisms in type 2 diabetes mellitus (T2DM) in a rat model of cognitive impairment.

MATERIALS AND METHODS

Twelve active ingredients in HLJDD were detected using high-performance liquid chromatography analysis. An animal model of cognitive dysfunction in T2DM was induced via a high-sugar and high-fat diet combined with a low dose of streptozotocin. Sprague-Dawley rats were randomly divided into six groups: control, T2DM, metformin (0.34 g/kg/day), and HLJDD groups (3, 1.5, and 0.75 g/kg/day). All treatments were intragastrically administrated for nine continuous weeks after the development of T2DM. Body weight, food and water intake, fasting blood glucose, insulin sensitivity, and blood lipid levels were measured. Spatial learning and memory of the rats were assessed using the Morris water maze test. Hematoxylin and eosin and Nissl staining were performed to evaluate neuronal morphology and vitality. Glutathione, malondialdehyde, and superoxide dismutase levels were measured to determine the level of oxidative stress in the hippocampus. Transmission electron microscopy was performed to observe the synaptic morphology and structure of hippocampal neurons. IL-1β levels in the hippocampus and cerebrospinal fluid were determined. The protein expression of NLRP3, cleaved caspase-1, mature IL-1β, ATG7, P62, LC3, and brain-derived neurotrophic factor (BDNF) was determined using western blotting and immunofluorescence analysis.

RESULTS

HLJDD attenuated cognitive dysfunction in rats with T2DM as shown by the decreased escape latency, increased times crossing the platform and time spent in the target quadrant in the Morris water maze test (P < 0.05), improvement in hippocampal histopathological changes, and an elevated level of cell vitality. HLJDD treatment also reduced blood glucose and lipid levels, ameliorated oxidative stress, and downregulated IL-1β expression in the hippocampus and cerebrospinal fluid (P < 0.05). Moreover, HLJDD enhanced BDNF, ATG7, and LC3 protein expression and significantly inhibited the expression of P62, NLRP3, cleaved caspase-1, and mature IL-1β in the hippocampal CA1 region (P < 0.05). Immunofluorescence results further confirmed that the fluorescence intensity of NLRP3 and P62 in the hippocampus decreased after HLJDD intervention (P < 0.05).

CONCLUSIONS

HLJDD ameliorated cognitive dysfunction in T2DM rats. The neuroprotective effect is exerted via the modulation of glucose and lipid metabolism, upregulation of autophagy, and inhibition of NLRP3 inflammasome signaling pathway.

Innate Immune Cell Death in Neuroinflammation and Alzheimer's Disease

Alzheimer’s disease (AD) is a neurodegenerative disorder molecularly characterized by the formation of amyloid β (Aβ) plaques and type 2 microtubule-associated protein (Tau) abnormalities. Multiple studies have shown that many of the brain’s immunological cells, specifically microglia and astrocytes, are involved in AD pathogenesis. Cells of the innate immune system play an essential role in eliminating pathogens but also regulate brain homeostasis and AD. When activated, innate immune cells can cause programmed cell death through multiple pathways, including pyroptosis, apoptosis, necroptosis, and PANoptosis. The cell death often results in the release of proinflammatory cytokines that propagate the innate immune response and can eliminate Aβ plaques and aggregated Tau proteins. However, chronic neuroinflammation, which can result from cell death, has been linked to neurodegenerative diseases and can worsen AD. Therefore, the innate immune response must be tightly balanced to appropriately clear these AD-related structural abnormalities without inducing chronic neuroinflammation. In this review, we discuss neuroinflammation, innate immune responses, inflammatory cell death pathways, and cytokine secretion as they relate to AD. Therapeutic strategies targeting these innate immune cell death mechanisms will be critical to consider for future preventive or palliative treatments for AD.

The Role of Glucagon-Like Peptide-1 Receptor Agonists (GLP-1 RA) in Diabetes-Related Neurodegenerative Diseases

Recent clinical guidelines have emphasized the importance of screening for cognitive impairment in older adults with diabetes, however, there is still a lack of understanding about the drug therapy. Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) are widely used in the treatment of type 2 diabetes and potential applications may include the treatment of obesity as well as the adjunctive treatment of type 1 diabetes mellitus in combination with insulin. Growing evidence suggests that GLP-1 RA has the potential to treat neurodegenerative diseases, particularly in diabetes-related Alzheimer’s disease (AD) and Parkinson’s disease (PD). Here, we review the molecular mechanisms of the neuroprotective effects of GLP-1 RA in diabetes-related degenerative diseases, including AD and PD, and their potential effects.

BRAIN ACTIVITIES OF STREPTOZOTOCIN-INDUCED DIABETIC WISTAR RATS TREATED WITH GLICLAZIDE: BEHAVIOURAL, BIOCHEMICAL AND HISTOMORPHOLOGY STUDIES

Gliclazide (GLD), a sulphonylurea is efficacious in the treatment of diabetes type-2. However, there is limited information on its activity in the brain, especially in diabetics. This research investigated the brain activities of GLD following streptozotocin-induced diabetes in Wistar rats. Twenty five adult male Wistar rats (200–250 g) were grouped (n = 5) as: Control (distilled water, 5 mL/kg) and GLD (150 mg/kg) groups; and the diabetic groups, untreated streptozotocin (STZ, 35 mg/kg), and STZ (35 mg/kg) treated with GLD (150 mg/kg) for two and four weeks, and already on high fat diet. The animals’ body weights and blood glucose levels were checked weekly. After the experimental duration, spontaneous alternation and novel object recognition tests were carried out and the animals sacrificed. Perfusion with phosphate buffered saline preceded brain excision for biochemical analyses, with halves fixed in 10% neutral buffered formalin for histology. Compared with the control, results showed (p < 0.05) declined spontaneous alternation and exploratory activities with no preference for familiar or novel objects, body weights loss, raised blood glucose, increased malondialdehyde with decreased superoxide dismutase concentrations, and no apparent adverse effect on hippocampal and prefrontal cortical Nissl substance in the untreated diabetic group. The adverse observations were attenuated in the GLD treated diabetic groups; although the spontaneous alternation in the four weeks GLD treated diabetic group improved (p < 0.05), exploration of objects increased (p < 0.05) without preference. The present results showed that treatment with GLD for two and four weeks mitigated STZ activities, even though there was less improvement in neurocognitive activities.

Comparative efficacy and safety of traditional Chinese patent medicine for cognitive dysfunction in diabetic cognitive dysfunction: A protocol for systematic review and Bayesian network meta-analysis

BACKGROUND

More and more studies have shown that cognitive dysfunction is one of the main complications of diabetes. The disorder of glucose and lipid metabolism seriously damages brain function and accelerates the conversion to dementia. At present, there are no drugs that can directly treat diabetic cognitive dysfunction. All drugs for the treatment of this disease achieve the purpose of treatment through strict control of blood sugar levels. This method has great limitations. Traditional Chinese patent medicines (TCPMs) work through multiple targets and multiple pathways, which can not only effectively correct the state of glucose and lipid metabolism disorders, but also significantly improve cognitive ability, but there is a lack of systematic evaluation of their effectiveness and safety. We use the method of network meta-analysis to systematically and comprehensively compare the effectiveness and safety of different Chinese patent medicines.

METHODS

We will comprehensively search the following databases, including Web of Science, PubMed, The Cochrane Library, EMBASE, China National Knowledge Infrastructure, Chinese Scientific Journals Database, Wanfang database and China BioMedical Literature. We will include all randomized controlled trials that meet the inclusion criteria, starting from the establishment of the database until September 2021. Two researchers will independently screen the literature based on inclusion criteria. While extracting data, we also assess the risk of bias in the included studies. All the data and evidence obtained will be evaluated by the method of Bayesian network meta-analysis.

RESULTS

This study will evaluate the effectiveness and safety of various TCPMs for diabetic cognitive dysfunction.

CONCLUSION

The results of this study will provide valuable references for the clinical application of TCPMs, and assist clinicians in formulating more reasonable diagnosis and treatment strategies.

ETHICS AND DISSEMINATION

This study does not require ethical approval.

INTERNATIONAL PLATFORM OF REGISTERED SYSTEMATIC REVIEW AND METAANALYSIS PROTOCOLS REGISTRATION NUMBER

INPLASY202190008.

A gliclazide complex based on palladium towards Alzheimer's disease: promising protective activity against Aβ-induced toxicity in C. elegans

A new palladium coordination compound based on gliclazide with the chemical formula [Pd(glz)₂] (where glz = gliclazide) has been synthesized and characterised. The structural characterization reveals that this material consists of mononuclear units formed by a Pd²⁺ ion coordinated to two molecules of the glz ligand, in which palladium ions exhibit a distorted plane-square coordination sphere. This novel material behaves like a good and selective inhibitor of butyrylcholinesterase, one of the most relevant therapeutic targets against Alzheimer's disease. Analysis of the enzyme kinetics showed a mixed mode of inhibition, the title compound being capable of interacting with both the free enzyme and the enzyme-substrate complex. Finally, the palladium compound shows promising protective activity against Aβ-induced toxicity in the Caenorhabditis elegans model, which has never been reported.

Swimming exercise decreases depression-like behaviour and inflammatory cytokines in a mouse model of type 2 diabetes

NEW FINDINGS

What is the central question of this study? Can swimming exercise decrease depression-like behaviour and inflammation in type 2 diabetic mice? What is the main finding and its importance? Swimming exercise decreased depression-like behaviour by reducing inflammation in type 2 diabetic mice. Swimming exercise might be useful for the treatment of depression-related disorders in patients with type 2 diabetes.

ABSTRACT

Clinical and experimental studies have shown that type 2 diabetes is associated with depression-related disorders. Inflammation has been identified as a common mechanism in both type 2 diabetes and depression. Several studies have suggested that swimming exercise might be able to reduce depression-related symptoms. The present study aimed to explore whether swimming exercise can decrease depression-like behaviour in type 2 diabetic mice. To induce type 2 diabetes, male C57BL6 mice were treated with a high-fat diet and streptozocin. Type 2 diabetic animals were subjected to swimming exercise for 4 weeks. Then, depression-like behaviours were evaluated by sucrose preference, novelty-suppressed feeding, social interaction and tail suspension tests. We also measured levels of glucose, insulin and pro-inflammatory cytokines such as interleukin-1β and tumour necrosis factor-α in the serum of animals. The results indicated that type 2 diabetes significantly increased anhedonia- and depression-like behaviours in mice. We also found significant increases in glucose, insulin and inflammatory cytokines in diabetic mice. Moreover, swimming exercise reduced anhedonia- and depression-like behaviour in type 2 diabetic mice. Swimming exercise also decreased glucose and inflammatory cytokines in the serum of mice with type 2 diabetes. Collectively, this study demonstrates that swimming exercise decreased depression-like behaviour by reducing inflammation in type 2 diabetic mice. Further clinical studies are needed to validate these findings in patients with type 2 diabetes.

Swimming exercise attenuates anxiety-like behavior by reducing brain oxidative stress in type 2 diabetic mice

Anxiety-related behaviors are among the most prevalent psychiatric disorders in patients with type 2 diabetes (T2D). The protective effect of exercise on neuropsychiatric disorders has been documented. However, there are no studies that examined whether swimming exercise can decrease anxiety-like symptoms in type 2 diabetes. We investigated the effects of swimming exercise on body weight, anxiety-like behavior, glucose and insulin levels, and brain oxidative stress in male C57BL/6 mice. T2D-induced mice were subjected to swimming exercise, then anxiety-like behaviors were measured by the open field, light-dark box, and elevated plus-maze tests. Glucose and insulin levels were measure in serum, and antioxidant/oxidative markers including glutathione (GSH), malondialdehyde (MDA), and glutathione disulfide (GSSG) were measured in the brain. Our findings showed that T2D increased body weight, anxiety-like symptoms, glucose and insulin resistance, and oxidative stress by increasing MDA and GSSG levels in the brain of mice. Interestingly, swimming exercise reversed these parameters in diabetic mice. Our findings clearly indicate that there is a protective impact of swimming exercise on anxiety-like behavior by reducing insulin resistance and brain oxidative stress in mice with type 2 diabetes. Further studies are needed to validate these findings in humans.

Perinatal fluoxetine dose-dependently affects prenatal stress-induced neurobehavioural abnormalities, HPA-axis functioning and underlying brain alterations in rat dams and their offspring

Both untreated and SSRI antidepressant treated maternal depression during the perinatal period can pose both short-and long-term health risks to the offspring. Therefore, it is essential to have an effective SSRI treatment consisting of the lowest effective dose beneficial to the mother, without causing adverse effects on offspring development. The effects of prenatal stress on neurobehavioral outcomes were studied in the pregnant and lactating rat dam, and her offspring. Furthermore, stressed dams were treated with different doses of fluoxetine (FLX; 5, 10and 25 mg/kg) during pregnancy and the postpartum period. We found that prenatal stress-induced anxiety-and depressive-like behaviour and increased HPA-axis function in pregnant and postpartum dams, and in offspring. Maternal stress impaired object recognition but did not affect spatial memory in offspring. Prenatal stress decreased whole-brain serotonin and brain-derived-neurotrophic-factor, and increased interleukin-17 and malondialdehyde, but did not affect oxytocin and interleukin-6 in the brains of offspring. Maternal treatment with 5 mg/kg FLX during the perinatal period did not rescue any stress-induced anxiety/depressive-like behaviour in the pregnant and postpartum dam and had only a few rescuing effects in offspring. Maternal FLX treatment with 10 mg/kg did rescue most stress-induced anxiety-and depressive-like behaviour or HPA-axis-function in dams and offspring. The highest dose tested, 25 mg/kg FLX, had the rescuing properties in dams while having the same, or an even greater, detrimental effect as prenatal stress on offspring behaviour and molecular alterations in the brain. Our results show prenatal stress rescuing properties for FLX treatment in the pregnant and postpartum dam, with dose-dependent effects on the offspring.

Glibenclamide treatment prevents depressive-like behavior and memory impairment induced by chronic unpredictable stress in female mice

Glibenclamide is a second-generation sulfonylurea used in the treatment of Type 2 Diabetes Mellitus. The primary target of glibenclamide is ATP-sensitive potassium channels inhibition; however, other possible targets include the control of inflammation and blood-brain barrier permeability, which makes this compound potentially interesting for the management of brain-related disorders. Here, we showed that systemic treatment with glibenclamide (5 mg/kg, p.o., for 21 days) could prevent the behavioral despair and the cognitive dysfunction induced by chronic unpredictable stress (CUS) in mice. In nonhypoglycemic doses, glibenclamide attenuated the stress-induced weight loss, decreased adrenal weight, and prevented the increase in glucocorticoid receptors in the prefrontal cortex, suggesting an impact in hypothalamic-pituitary-adrenal (HPA) axis function. Additionally, we did not observe changes in Iba-1, NLRP3 and caspase-1 levels in the prefrontal cortex or hippocampus after CUS or glibenclamide treatment. Thus, this study suggests that chronic treatment with glibenclamide prevents the emotional and cognitive effects of chronic stress in female mice. On the other hand, the control of neuroinflammation and NLRP3 inflammasome pathway is not the major mechanism mediating these effects. The behavioral effects might be mediated, in part, by the normalization of glucocorticoid receptors and HPA axis.

Environmental enrichment alters neurobehavioral development following maternal immune activation in mice offspring with epilepsy

Epilepsy is a chronic brain disease affecting millions of people worldwide. Anxiety-related disorders and cognitive deficits are common in patients with epilepsy. Previous studies have shown that maternal infection/immune activation renders children more vulnerable to neurological disorders later in life. Environmental enrichment has been suggested to improve seizures, anxiety, and cognitive impairment in animal models. The present study aimed to explore the effects of environmental enrichment on seizure scores, anxiety-like behavior, and cognitive deficits following maternal immune activation in offspring with epilepsy. Pregnant mice were treated with lipopolysaccharides-(LPS) or vehicle, and offspring were housed in normal or enriched environments during early adolescence to adulthood. To induce epilepsy, adult male and female offspring were treated with Pentylenetetrazol-(PTZ), and then anxiety-like behavior and cognitive functions were assessed. Tumor-necrosis-factor (TNF)-α and interleukin (IL) 10 were measured in the hippocampus of offspring. Maternal immune activation sex-dependently increased seizure scores in PTZ-treated offspring. Significant increases in anxiety-like behavior, cognitive impairment, and hippocampal TNF-α and IL-10 were also found following maternal immune activation in PTZ-treated offspring. However, there was no sex difference in these behavioral abnormalities in offspring. Environmental enrichment reversed the effects of maternal immune activation on behavioral and inflammatory parameters in PTZ-treated offspring. Overall, the present findings highlight the adverse effects of prenatal maternal immune activation on seizure susceptibility and psychiatric comorbidities in offspring. This study suggests that environmental enrichment may be used as a potential treatment approach for behavioral abnormalities following maternal immune activation in PTZ-treated offspring.

Pharmacological Inhibition of Transient Receptor Potential Melastatin 2 (TRPM2) Channels Attenuates Diabetes-induced Cognitive Deficits in Rats: A Mechanistic Study

Background:

Diabetes is a chronic metabolic disorder affecting the central nervous system. A growing body of evidence has depicted that high glucose level leads to the activation of the transient receptor potential melastatin 2 (TRPM2) channels. However, there are no studies targeting TRPM2 channels in diabetes-induced cognitive decline using a pharmacological approach.

Objective:

The present study intended to investigate the effects of 2-aminoethoxydiphenyl borate (2-APB), a TRPM2 inhibitor, in diabetes-induced cognitive impairment.

Methods:

Streptozotocin (STZ, 50 mg/kg, i.p.) was used to induce diabetes in rats. Animals were randomly divided into the treatment group, model group and age-matched control and pre se group. 2-APB treatment was given for three weeks to the animals. After 10 days of behavioural treatment, parameters were performed. Animals were sacrificed at 10th week of diabetic induction and the hippocampus and cortex were isolated. After that, protein and mRNA expression study was performed in the hippocampus. Acetylcholinesterase (AchE) activity was done in the cortex.

Results: :

Our study showed the 10th week diabetic animals developed cognitive impairment, which was evident from the behavioural parameters. Diabetic animals depicted an increase in the TRPM2 mRNA and protein expression in the hippocampus as well as increased AchE activity in the cortex. However, memory associated proteins were down-regulated, namely Ca2+/calmodulin-dependent protein kinase II (CaMKII-Thr286), glycogen synthase kinase 3 beta (GSK-3β-Ser9), cAMP response element-binding protein (CREB-Ser133), and postsynaptic density protein 95 (PSD-95). Gene expression of parvalbumin, calsequestrin and brain-derived neurotrophic factor (BDNF) were down-regulated while mRNA level of calcineurin A/ protein phosphatase 3 catalytic subunit alpha (PPP3CA) was upregulated in the hippocampus of diabetic animals. A three-week treatment with 2-APB significantly ameliorated the alteration in behavioural cognitive parameters in diabetic rats. Moreover, 2-APB also down-regulated the expression of TRPM2 mRNA and protein in the hippocampus as well as AchE activity in the cortex of diabetic animals as compared to diabetic animals. Moreover, the 2-APB treatment also upregulated the CaMKII (Thr-286), GSK-3β (Ser9), CREB (Ser133), and PSD-95 expression and mRNA levels of parvalbumin, calsequestrin, and BDNF while mRNA level of calcineurin A was down-regulated in the hippocampus of diabetic animals.

Conclusion: :

This study confirms the ameliorative effect of TRPM2 channel inhibitor in the diabetes- induced cognitive deficits. Inhibition of TRPM2 channels reduced the calcium associated downstream signaling and showed a neuroprotective effect of TRPM2 channels in diabetesinduced cognitive impairment.

Repositioning medication for cardiovascular and cerebrovascular disease to delay the onset and prevent progression of Alzheimer's disease

Alzheimer's disease (AD) is a complex, progressive, neurodegenerative disorder. As with other common chronic diseases, multiple risk factors contribute to the onset and progression of AD. Many researchers have evaluated the epidemiologic and pathophysiological association between AD, cardiovascular diseases (CVDs), and cerebrovascular diseases (CBVDs), including commonly reported risk factors such as diabetes, hypertension, and dyslipidemia. Relevant therapies of CVDs/CBVDs for the attenuation of AD have also been empirically investigated. Considering the challenges of new drug development, in terms of cost and time, multifactorial approaches such as therapeutic repositioning of CVD/CBVD medication should be explored to delay the onset and progression of AD. Thus, in this review, we discuss our current understanding of the association between cardiovascular risk factors and AD, as revealed by clinical and non-clinical studies, as well as the therapeutic implications of CVD/CBVD medication that may attenuate AD. Furthermore, we discuss future directions by evaluating ongoing trials in the field.

Glibenclamide modulates microglial function and attenuates Aβ deposition in 5XFAD mice

Severe neuroinflammation is known as a main pathology of neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). In these diseases, excessive microglial activation is one of the main causes of inflammation in the central nervous system. Therefore, inhibition of activated microglia may be suggested as a treatment for neuroinflammatory diseases. Glibenclamide, known as a therapeutics for type 2 diabetes in clinical trials has been shown to be effective in the inhibiting inflammatory conditions of various diseases. However, studies on the effects of glibenclamide for improving AD pathologies are little known. In this study, we tested glibenclamide on microglial cell line BV2 and 5XFAD mice. We found that glibenclamide significantly inhibited nitric oxide (NO) at 10 μM and 40 μM in BV2 cells induced by lipopolysaccharide (LPS) stimulation. In addition, we confirmed that 40 μM of glibenclamide reduced pro-inflammatory cytokines and proteins in the LPS-stimulated microglial cells. The anti-inflammatory effect of glibenclamide was further tested in APP/PS1 transgenic mouse. Although further analysis would be needed to confirm whether glibenclamide affects behavioral performance, our data suggests that glibenclamide may be a therapeutic option for AD treatment.

Prenatal maternal stress alters depression-related symptoms in a strain - and sex-dependent manner in rodent offspring

Stress during pregnancy adversely affects foetal development and leads to later behavioural outcomes in offspring. Preclinical studies have reported conflicting effects of prenatal stress on depression-related symptoms in rodent offspring. This study aimed to study the combined effect of strain and sex on prenatal stress outcomes in a single study. To this end, male and female offspring from outbred Wistar and inbred Lewis rats, and outbred NMRI and inbred C57BL6 mice were compared. As outcomes we focussed on depression-related behaviour and related molecular and neurochemical parameters. Prenatally stressed and non-stressed offspring were subjected to the sucrose preference, novelty-suppressed feeding, tail suspension, and forced swim tests. We measured basal and stress-induced corticosterone levels in the serum, and brain-derived-neurotrophic-factor (BDNF), interleukin-1β, tumor necrosis factor-α, glutamate and serotonin in the brain to determine changes in hypothalamic-pituitary-adrenal-(HPA)-axis function, neuroplasticity, neuroinflammation, and neurotransmission. Our findings revealed that prenatal stress increases depression-like behaviour, HPA-axis (re) activity, pro-inflammatory cytokines and glutamate levels, and decreases BDNF and serotonin levels in a strain and sex-dependent manner in rodent offspring. Overall, male and female Lewis rats, female Wistar rats, male NMRI mice and female C57BL6 mice were found to be most responsive to prenatal stress. Based on these results, we conclude that genetic background and sex contribute to the great diversity in the effects of prenatal maternal stress in rodents.