Are ketogenic diets promising for Alzheimer's disease? A translational review

The Potential Role of Mitochondria in the Microbiota-Gut-Brain Axis: Implications for Brain Health

Mitochondria are crucial organelles that regulate cellular energy metabolism, calcium homeostasis, and oxidative stress responses, playing pivotal roles in brain development and neurodegeneration. Concurrently, the gut microbiota has emerged as a key modulator of brain physiology and pathology through the microbiota-gut-brain axis. Recent evidence suggests an intricate crosstalk between the gut microbiota and mitochondrial function, mediated by microbial metabolites that can influence mitochondrial activities in the brain. This review aims to provide a comprehensive overview of the emerging role of mitochondria as critical mediators in the microbiota-gut-brain axis, shaping brain health and neurological disease pathogenesis. We discuss how gut microbial metabolites such as short-chain fatty acids, secondary bile acids, tryptophan metabolites, and trimethylamine N-oxide can traverse the blood-brain barrier and modulate mitochondrial processes including energy production, calcium regulation, mitophagy, and oxidative stress in neurons and glial cells. Additionally, we proposed targeting the mitochondria through diet, prebiotics, probiotics, or microbial metabolites as a promising potential therapeutic approach to maintain brain health by optimizing mitochondrial fitness. Overall, further investigations into how the gut microbiota and its metabolites regulate mitochondrial bioenergetics, dynamics, and stress responses will provide valuable insights into the microbiota-gut-brain axis in both health and disease states.

Effects of ketogenic diet on cognitive function of patients with Alzheimer's disease: a systematic review and meta-analysis

BACKGROUND

Ketogenic diets (KD) have shown remarkable effects in many disease areas. It has been demonstrated in numerous animal experiments that KD is effective in the treatment of Alzheimer's disease (AD). But the clinical effect of treating AD is uncertain.

OBJECTIVE

To systematically review the impact of KD on cognitive function in AD.

METHODS

We conducted a search of three international databases-PubMed, Cochrane Library, and Embase-to retrieve RCTs on the KD intervention for AD from the inception of the databases through October 2023. Two reviewers searched and screened the literature, extracted and checked relevant data independently, and assessed the risk of bias of the included studies. The meta-analysis was carried out utilizing RevMan 5.3 software.

RESULTS

A total of 10 RCTS involving 691 patients with AD were included. There were 357 participants in the intervention group and 334 participants in the control group. The duration of the KD intervention ranged from a minimum of 3 months to a maximum of 15 months. Meta-analysis results showed that KD could effectively improve the mental state of the elderly (NM scale) [MD = 7.56, 95%CI (3.02, 12.10), P = 0.001], MMSE [MD = 1.25, 95%CI (0.46, 2.04), P = 0.002], and ADAS-Cog [MD = -3.43, 95%CI (-5.98, -0.88), P = 0.008]. The elevation of ketone body (β-hydroxybutyric) [MD = 118.84, 95%CI (15.20, 222.48), P = 0.02] may also lead to the elevation of triglyceride [MD = 0.19, 95%CI (0.03, 0.35), P = 0.02] and low density lipoprotein [MD = 0.31, 95%CI (0.04, 0.58), P = 0.02].

CONCLUSION

Research conducted has indicated that the KD can enhance the mental state and cognitive function of those with AD, albeit potentially leading to an elevation in blood lipid levels. In summary, the good intervention effect and safety of KD are worthy of promotion and application in clinical treatment of AD.

β-Hydroxybutyrate and melatonin suppress maladaptive UPR, excessive autophagy and pyroptosis in Aβ 1-42 and LPS-Induced SH-SY5Y cells

BACKGROUND

Alzheimer's disease is a neurological disease characterized by the build-up of amyloid beta peptide (Aβ) and lipopolysaccharide (LPS), which causes synapse dysfunction, cell death, and neuro-inflammation. A maladaptive unfolded protein response (UPR), excessive autophagy, and pyroptosis aggravate the disease. Melatonin (MEL) and hydroxybutyrate (BHB) have both shown promise in terms of decreasing Aβ pathology. The goal of this study was to see how BHB and MEL affected the UPR, autophagy, and pyroptosis pathways in Aβ1-42 and LPS-induced SH-SY5Y cells.

MATERIALS AND METHODS

Human neuroblastoma SH-SY5Y cells were treated with BHB, MEL, or a combination of the two after being exposed to A β1-42 and LPS. Cell viability was determined using the MTT test, and gene expression levels of UPR (ATF6, PERK, and CHOP), autophagy (Beclin-1, LC3II, P62, and Atg5), and pyroptosis-related markers (NLRP3, TXNIP, IL-1β, and NFκB1) were determined using quantitative Real-Time PCR (qRT-PCR). For statistical analysis, one-way ANOVA was employed, followed by Tukey's post hoc test.

RESULTS

BHB and MEL significantly increased SH-SY5Y cell viability in the presence of A β1-42 and LPS. Both compounds inhibited the expression of maladaptive UPR and autophagy-related genes, as well as inflammatory and pyroptotic markers caused by Aβ1-42 and LPS-induced SH-SY5Y cells.

CONCLUSION

BHB and MEL rescue neurons in A β1-42 and LPS-induced SH-SY5Y cells by reducing maladaptive UPR, excessive autophagy, and pyroptosis. More research is needed to fully comprehend the processes behind their beneficial effects and to discover their practical applications in the treatment of neurodegenerative disorders.

ESPEN guideline on nutrition and hydration in dementia - Update 2024

BACKGROUND & AIMS

Dementia is accompanied by a variety of changes that result in an increased risk of malnutrition and low-intake dehydration. This guideline update aims to give evidence-based recommendations for nutritional care of persons with dementia in order to prevent and treat these syndromes.

METHODS

The previous guideline version was reviewed and expanded in accordance with the standard operating procedure for ESPEN guidelines. Based on a systematic search in three databases, strength of evidence of appropriate literature was graded by use of the SIGN system. The original recommendations were reviewed and reformulated, and new recommendations were added, which all then underwent a consensus process.

RESULTS

40 recommendations for nutritional care of older persons with dementia were developed and agreed, seven at institutional level and 33 at individual level. As a prerequisite for good nutritional care, organizations caring for persons with dementia are recommended to employ sufficient qualified staff and offer attractive food and drinks with choice in a functional and appealing environment. Nutritional care should be based on a written care concept with standardized operating procedures. At the individual level, routine screening for malnutrition and dehydration, nutritional assessment and close monitoring are unquestionable. Oral nutrition may be supported by eliminating potential causes of malnutrition and dehydration, and adequate social and nursing support (including assistance, utensils, training and oral care). Oral nutritional supplements are recommended to improve nutritional status but not to correct cognitive impairment or prevent cognitive decline. Routine use of dementia-specific ONS, ketogenic diet, omega-3 fatty acid supplementation and appetite stimulating agents is not recommended. Enteral and parenteral nutrition and hydration are temporary options in patients with mild or moderate dementia, but not in severe dementia or in the terminal phase of life. In all stages of the disease, supporting food and drink intake and maintaining or improving nutrition and hydration status requires an individualized, comprehensive approach. Due to a lack of appropriate studies, most recommendations are good practice points.

CONCLUSION

Nutritional care should be an integral part of dementia management. Numerous interventions are available that should be implemented in daily practice. Future high-quality studies are needed to clarify the evidence.

Combined Catalpol and Tetramethylpyrazine Promote Axonal Plasticity in Alzheimer's Disease by Inducing Astrocytes to Secrete Exosomes Carrying CDK5 mRNA and Regulating STAT3 Phosphorylation

Alzheimer's disease (AD) is a common progressive degenerative disease of the central nervous system in aging populations. This study aimed to investigate the effects of combined catalpol and tetramethylpyrazine (CT) in promoting axonal plasticity in AD and the potential underlying mechanism. Astrocytes were treated with different concentrations of compatible CT. Exosomes were collected and subjected to sequencing analysis, which was followed by the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differentially expressed genes. Amyloid precursor protein/presenilin 1 (APP/PS1) double-transfected male mice were used as the in vivo AD models. Astrocyte-derived exosomes that were transfected with cyclin-dependent kinase 5 (CDK5) or CT treatment were injected into the tail vein of mice. The levels of CDK5, synaptic plasticity marker protein neurofilament 200 (NF200), and growth-associated protein 43 (GAP-43) in the hippocampus of mice were compared in each group. Immunofluorescence staining was used to detect the localization of STAT3 and to visualize synaptic morphology via β-tubulin-III (TUBB3). Astrocyte-derived exosomes transfected with siCDK5 or treated with CT were co-cultured with HT-22 cells, which were untransfected or silenced for signal transducer and activator of transcription 3 (STAT3). Amyloid β-protein (Aβ)1-42 was induced in the in vitro AD models. The viability, apoptosis, and expression levels of NF200 and GAP-43 proteins in the hippocampal neurons of each group were compared. In total, 166 differentially expressed genes in CT-induced astrocyte-derived exosomes were included in the KEGG analysis, and they were found to be enriched in 12 pathways, mainly in axon guidance. CT treatment significantly increased the level of CDK5 mRNA in astrocyte-derived exosomes-these exosomes restored CDK5 mRNA and protein levels in the hippocampus of the in vivo AD model mice and the in vitro AD model; promoted p-STAT3 (Ser727), NF200 and GAP-43 proteins; and promoted the regeneration and extension of neuronal synapses. Silencing of CDK5 blocked both neuronal protection as well as induction of axonal plasticity in AD by CT-treated exosomes in vitro and in vivo. Moreover, silencing of STAT3 blocked both neuronal protection as well as induction of axonal plasticity in AD caused by CDK5 overexpression or CT-treated astrocyte-induced exosomes. CT promotes axonal plasticity in AD by inducing astrocytes to secrete exosomes carrying CDK5 mRNA and regulating STAT3 (Ser727) phosphorylation.

The relationship between gender differences in dietary habits, neuroinflammation, and Alzheimer's disease

Neurocognitive decline is one of the foremost dire issues in medicine today. The mechanisms by which dementia pathogenesis ensues are complicated and multifactorial, particularly in the case of Alzheimer's disease (AD). One irrefutable, yet unexplained factor is the gender disparity in AD, in which women are disproportionately affected by AD, both in the rate and severity of the disease. Examining the multifaceted contributing causes along with unique gender dynamics in modifiable risk factors, such as diet, may lend some insight into why this disparity exists and potential paths forward. The aim of this brief narrative review is to summarize the current literature of gender differences in dietary habits and how they may relate to neuroinflammatory states that contribute to AD pathogenesis. As such, the interplay between diet, hormones, and inflammation will be discussed, along with potential interventions to inform care practices.

A randomized feasibility trial of the modified Atkins diet in older adults with mild cognitive impairment due to Alzheimer's disease

Background

Alzheimer's disease (AD) is increasing in prevalence, but effective treatments for its cognitive impairment remain severely limited. This study investigates the impact of ketone body production through dietary manipulation on memory in persons with mild cognitive impairment due to early AD and explores potential mechanisms of action.

Methods

We conducted a 12-week, parallel-group, controlled feasibility trial of a ketogenic diet, the modified Atkins diet (MAD), compared to a control diet in patients with cognitive impairments attributed to AD. We administered neuropsychological assessments, including memory tests, and collected blood samples at baseline and after 12 weeks of intervention. We performed untargeted lipidomic and targeted metabolomic analyses on plasma samples to detect changes over time.

Results

A total of 839 individuals were screened to yield 38 randomized participants, with 20 assigned to receive MAD and 18 assigned to receive a control diet. Due to attrition, only 13 in the MAD arm and nine in the control arm were assessed for the primary endpoint, with two participants meeting ketosis levels used to define MAD adherence criteria. The average change from baseline in the Memory Composite Score was 1.37 (95% CI: -0.87, 4.90) points higher in the MAD group compared to the control group. The effect size of the intervention on baseline MAD change was moderate (Cohen's D = 0.57, 95% CI: -0.67, 1.33). In the 15 participants (nine MAD, six control) assessed for lipidomic and metabolomic-lipidomics and metabolomics, 13 metabolites and 10 lipids showed significant changes from baseline to 12 weeks, including triacylglycerols (TAGs, 50:5, 52:5, and 52:6), sphingomyelins (SM, 44:3, 46:0, 46:3, and 48:1), acetoacetate, fatty acylcarnitines, glycerol-3-phosphate, and hydroxy fatty acids.

Conclusions

Attrition was greatest between baseline and week 6. All participants retained at week 6 completed the study. Despite low rates of adherence by criteria defined a priori, lipidomic and metabolomic analyses indicate significant changes from baseline in circulating lipids and metabolites between MAD and control participants at 12-week postrandomization, and MAD participants showed greater, albeit nonsignificant, improvement in memory.

Emergence of Extracellular Vesicles as "Liquid Biopsy" for Neurological Disorders: Boom or Bust

Extracellular vesicles (EVs) have emerged as an attractive liquid biopsy approach in the diagnosis and prognosis of multiple diseases and disorders. The feasibility of enriching specific subpopulations of EVs from biofluids based on their unique surface markers has opened novel opportunities to gain molecular insight from various tissues and organs, including the brain. Over the past decade, EVs in bodily fluids have been extensively studied for biomarkers associated with various neurological disorders, such as Alzheimer's disease, Parkinson's disease, schizophrenia, bipolar disorder, major depressive disorders, substance use disorders, human immunodeficiency virus-associated neurocognitive disorder, and cancer/treatment-induced neurodegeneration. These studies have focused on the isolation and cargo characterization of either total EVs or brain cells, such as neuron-, astrocyte-, microglia-, oligodendrocyte-, pericyte-, and endothelial-derived EVs from biofluids to achieve early diagnosis and molecular characterization and to predict the treatment and intervention outcomes. The findings of these studies have demonstrated that EVs could serve as a repetitive and less invasive source of valuable molecular information for these neurological disorders, supplementing existing costly neuroimaging techniques and relatively invasive measures, like lumbar puncture. However, the initial excitement surrounding blood-based biomarkers for brain-related diseases has been tempered by challenges, such as lack of central nervous system specificity in EV markers, lengthy protocols, and the absence of standardized procedures for biological sample collection, EV isolation, and characterization. Nevertheless, with rapid advancements in the EV field, supported by improved isolation methods and sensitive assays for cargo characterization, brain cell-derived EVs continue to offer unparallel opportunities with significant translational implications for various neurological disorders. SIGNIFICANCE STATEMENT: Extracellular vesicles present a less invasive liquid biopsy approach in the diagnosis and prognosis of various neurological disorders. Characterizing these vesicles in biofluids holds the potential to yield valuable molecular information, thereby significantly impacting the development of novel biomarkers for various neurological disorders. This paper has reviewed the methodology employed to isolate extracellular vesicles derived from various brain cells in biofluids, their utility in enhancing the molecular understanding of neurodegeneration, and the potential challenges in this research field.

A modified Mediterranean-style diet enhances brain function via specific gut-microbiome-brain mechanisms

Alzheimer's disease (AD) is a debilitating brain disorder with rapidly mounting prevalence worldwide, yet no proven AD cure has been discovered. Using a multi-omics approach in a transgenic AD mouse model, the current study demonstrated the efficacy of a modified Mediterranean-ketogenic diet (MkD) on AD-related neurocognitive pathophysiology and underlying mechanisms related to the gut-microbiome-brain axis. The findings revealed that MkD induces profound shifts in the gut microbiome community and microbial metabolites. Most notably, MkD promoted growth of the Lactobacillus population, resulting in increased bacteria-derived lactate production. We discovered elevated levels of microbiome- and diet-derived metabolites in the serum as well, signaling their influence on the brain. Importantly, these changes in serum metabolites upregulated specific receptors that have neuroprotective effects and induced alternations in neuroinflammatory-associated pathway profiles in hippocampus. Additionally, these metabolites displayed strong favorable co-regulation relationship with gut-brain integrity and inflammatory markers, as well as neurobehavioral outcomes. The findings underscore the ameliorative effects of MkD on AD-related neurological function and the underlying gut-brain communication via modulation of the gut microbiome-metabolome arrays.

Ketogenic diet alleviates cognitive dysfunction and neuroinflammation in APP/PS1 mice via the Nrf2/HO-1 and NF-κB signaling pathways

Alzheimer's disease is a progressive neurological disorder characterized by cognitive decline and chronic inflammation within the brain. The ketogenic diet, a widely recognized therapeutic intervention for refractory epilepsy, has recently been proposed as a potential treatment for a variety of neurological diseases, including Alzheimer's disease. However, the efficacy of ketogenic diet in treating Alzheimer's disease and the underlying mechanism remains unclear. The current investigation aimed to explore the effect of ketogenic diet on cognitive function and the underlying biological mechanisms in a mouse model of Alzheimer's disease. Male amyloid precursor protein/presenilin 1 (APP/PS1) mice were randomly assigned to either a ketogenic diet or control diet group, and received their respective diets for a duration of 3 months. The findings show that ketogenic diet administration enhanced cognitive function, attenuated amyloid plaque formation and proinflammatory cytokine levels in APP/PS1 mice, and augmented the nuclear factor-erythroid 2-p45 derived factor 2/heme oxygenase-1 signaling pathway while suppressing the nuclear factor-kappa B pathway. Collectively, these data suggest that ketogenic diet may have a therapeutic potential in treating Alzheimer's disease by ameliorating the neurotoxicity associated with Aβ-induced inflammation. This study highlights the urgent need for further research into the use of ketogenic diet as a potential therapy for Alzheimer's disease.

A Modified Mediterranean Ketogenic Diet mitigates modifiable risk factors of Alzheimer's Disease: a serum and CSF-based metabolic analysis

Alzheimer's disease (AD) is influenced by a variety of modifiable risk factors, including a person's dietary habits. While the ketogenic diet (KD) holds promise in reducing metabolic risks and potentially affecting AD progression, only a few studies have explored KD's metabolic impact, especially on blood and cerebrospinal fluid (CSF). Our study involved participants at risk for AD, either cognitively normal or with mild cognitive impairment. The participants consumed both a modified Mediterranean-ketogenic diet (MMKD) and the American Heart Association diet (AHAD) for 6 weeks each, separated by a 6-week washout period. We employed nuclear magnetic resonance (NMR)-based metabolomics to profile serum and CSF and metagenomics profiling on fecal samples. While the AHAD induced no notable metabolic changes, MMKD led to significant alterations in both serum and CSF. These changes included improved modifiable risk factors, like increased HDL-C and reduced BMI, reversed serum metabolic disturbances linked to AD such as a microbiome-mediated increase in valine levels, and a reduction in systemic inflammation. Additionally, the MMKD was linked to increased amino acid levels in the CSF, a breakdown of branched-chain amino acids (BCAAs), and decreased valine levels. Importantly, we observed a strong correlation between metabolic changes in the CSF and serum, suggesting a systemic regulation of metabolism. Our findings highlight that MMKD can improve AD-related risk factors, reverse some metabolic disturbances associated with AD, and align metabolic changes across the blood-CSF barrier.

The proteomic effects of ketone bodies: implications for proteostasis and brain proteinopathies

A growing body of evidence supports the beneficial effects of the ketone bodies (KBs), acetoacetate and β-hydroxybutyrate (BHB), on diverse physiological processes and diseases. Hence, KBs have been suggested as therapeutic tools for neurodegenerative diseases. KBs are an alternative fuel during fasting and starvation as they can be converted to Ac-CoA to produce ATP. A ketogenic diet (KD), enriched in fats and low in carbohydrates, induces KB production in the liver and favors their use in the brain. BHB is the most abundant KB in the circulation; in addition to its role as energy fuel, it exerts many actions that impact the set of proteins in the cell and tissue. BHB can covalently bind to proteins in lysine residues as a new post-translational modification (PTM) named β-hydroxybutyrylation (Kbhb). Kbhb has been identified in many proteins where Kbhb sites can be critical for binding to other proteins or cofactors. Kbhb is mostly found in proteins involved in chromatin structure, DNA repair, regulation of spliceosome, transcription, and oxidative phosphorylation. Histones are the most studied family of proteins with this PTM, and H3K9bhb is the best studied histone mark. Their target genes are mainly related to cell metabolism, chromatin remodeling and the control of circadian rhythms. The role of Kbhb on physiological processes is poorly known, but it might link KB metabolism to cell signaling and genome regulation. BHB also impacts the proteome by influencing proteostasis. This KB can modulate the Unfolded Protein Response (UPR) and autophagy, two processes involved in the maintenance of protein homeostasis through the clearance of accumulated unfolded and damaged proteins. BHB can support proteostasis and regulate the UPR to promote metabolism adaptation in the liver and prevent cell damage in the brain. Also, BHB stimulates autophagy aiding to the degradation of accumulated proteins. Protein aggregation is common to proteinopathies like Alzheimer's (AD) and Parkinson's (PD) diseases, where the KD and BHB treatment have shown favorable effects. In the present review, the current literature supporting the effects of KBs on proteome conformation and proteostasis is discussed, as well as its possible impact on AD and PD.

Gut Microbiota and its Metabolites: Bridge of Dietary Nutrients and Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive cognitive impairment and neuroinflammation. Recent research has revealed the crucial role of gut microbiota and microbial metabolites in modulating AD. However, the mechanisms by which the microbiome and microbial metabolites affect brain function remain poorly understood. Here, we review the literature on changes in the diversity and composition of the gut microbiome in patients with AD and in animal models of AD. We also discuss the latest progress in understanding the pathways by which the gut microbiota and microbial metabolites from the host or diet regulate AD. By understanding the effects of dietary components on brain function, microbiota composition, and microbial metabolites, we examine the potential for manipulation of the gut microbiota through dietary intervention to delay the progression of AD. Although it is challenging to translate our understanding of microbiome-based approaches to dietary guidelines or clinical therapies, these findings provide an attractive target for promoting brain function.

Dietary low- and high-quality carbohydrate intake and cognitive decline: A prospective cohort study in older adults

BACKGROUND & AIMS

The association of dietary intake of carbohydrate (CHO), especially high- and low-quality CHO, with the decline of cognitive function remains uncertain. We aimed to investigate the prospective association of dietary total, low- and high-quality CHO intake with cognitive decline, and further examine the effect of isocaloric substitution with protein or fat, in the elderly population.

METHODS

A total of 3106 Chinese participants aged ≥55 years from China Health and Nutrition Survey (CHNS) were included in this study. Dietary nutrient intake information was collected by 24-h dietary recalls on 3 consecutive days. The cognitive decline was defined as the 5-year decline rates in global or composite cognitive scores based on a subset of items from the Telephone Interview for Cognitive Status-modified (TICS-m).

RESULTS

The median follow-up duration was 5.9 years. There was a significantly positive association of dietary low-quality CHO (per 10 percentage energy [%E] increment, β, 0.06; 95%CI, 0.01-0.11) and a no significant association of dietary high-quality CHO (per 10%E increment, β, 0.04; 95%CI, -0.07-0.14) with the 5-year decline rate in the composite cognitive scores. Similar results were found for the global cognitive scores. In model simulations, substituting dietary low-quality CHO with isocaloric animal protein or fat, instead of isocaloric plant protein or fat, was significantly and inversely associated with cognitive decline (All P values < 0.05).

CONCLUSIONS

The dietary intake of low-quality CHO, rather than high-quality CHO, was significantly associated with a faster cognitive decline in the elderly. In model simulations, isocaloric substitution of dietary low-quality CHO with animal protein or fat, rather than plant protein or fat, was inversely associated with cognitive decline.

Impact of Diet and Exercise Interventions on Cognition and Brain Health in Older Adults: A Narrative Review

The ability to preserve cognitive function and protect brain structure from the effects of the aging process and neurodegenerative disease is the goal of non-pharmacologic, lifestyle interventions focused on brain health. This review examines, in turn, current diet and exercise intervention trends and the collective progress made toward understanding their impact on cognition and brain health. The diets covered in this review include the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH), Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), ketogenic diet, intermittent fasting, and weight loss management. The exercise approaches covered in this review include endurance, resistance, combined exercise programs, yoga, tai chi, and high-intensity interval training. Although valuable evidence is building concerning how diet and exercise influence cognitive performance and brain structure, many of the open questions in the field are concerned with why we see these effects. Therefore, more strategically designed intervention studies are needed to reveal the likely multiple mechanisms of action in humans.

GLUT inhibitor WZB117 induces cytotoxicity with increased production of amyloid-beta peptide in SH-SY5Y cells preventable by beta-hydroxybutyrate: implications in Alzheimer's disease

BACKGROUND

Inhibitors of glucose transporters are being explored as potential anti-cancer drugs. Decreased cerebral glucose utilization with reduced levels of several glucose transporters is also an important pathogenic signature of neurodegeneration of Alzheimer's disease, but its exact role in the pathogenesis of this disease is not established. We explored in an experimental model if inhibitors of glucose transporters could lead to altered amyloid-beta homeostasis, mitochondrial dysfunction, and neuronal death, which are relevant in the pathogenesis of Alzheimer's disease.

METHODS

SH-SY5Y cells (human neuroblastoma cell line) were exposed to an inhibitor (WZB117) of several types of glucose transporters. We examined the effects of glucose hypometabolism on SH-SY5Y cells in terms of mitochondrial functions, production of reactive oxygen species, amyloid-beta homeostasis, and neural cell death. The effect of β-hydroxybutyrate in ameliorating the effects of WZB117 on SH-SY5Y cells was also examined.

RESULTS

We observed that exposure of SH-SY5Y cells to WZB117 caused mitochondrial dysfunction, increased production of reactive oxygen species, loss of cell viability, increased expression of BACE 1, and intracellular accumulation of amyloid β peptide (Aβ42). All the effects of WZB117 could be markedly prevented by co-treatment with β-hydroxybutyrate. Cyclosporine A, a blocker of mitochondrial permeability transition pore (mPTP) activation, could not prevent cell death caused by WZB117.

CONCLUSION

Results in this neuroblastoma model have implications for the pathogenesis of Alzheimer's disease and warrant further explorations of WZB117 in primary cultures of neurons and experimental animal models.

Nutritional intervention for diabetes mellitus with Alzheimer's disease

The combined disease burden of diabetes mellitus (DM) and Alzheimer's disease (AD) is increasing, and the two diseases share some common pathological changes. However, the pharmacotherapeutic approach to this clinical complexity is limited to symptomatic rather than disease-arresting, with the possible exception of metformin. Whether nutritional intervention might extend or synergize with these effects of metformin is of interest. In particular, dietary patterns with an emphasis on dietary diversity shown to affect cognitive function are of growing interest in a range of food cultural settings. This paper presents the association between diabetes and AD. In addition, the cross-cultural nutritional intervention programs with the potential to mitigate both insulin resistance (IR) and hyperglycemia, together with cognitive impairment are also reviewed. Both dietary patterns and nutritional supplementation showed the effects of improving glycemic control and reducing cognitive decline in diabetes associated with AD, but the intervention specificity remained controversial. Multi-nutrient supplements combined with diverse diets may have preventive and therapeutic potential for DM combined with AD, at least as related to the B vitamin group and folate-dependent homocysteine (Hcy). The nutritional intervention has promise in the prevention and management of DM and AD comorbidities, and more clinical studies would be of nutritional scientific merit.

A Novel Ketone-Supplemented Diet Improves Recognition Memory and Hippocampal Mitochondrial Efficiency in Healthy Adult Mice

Mitochondrial dysfunction and cognitive impairment are common symptoms in many neurologic and psychiatric disorders, as well as nonpathological aging. Ketones have been suggested as therapeutic for their efficacy in epilepsy and other brain pathologies such as Alzheimer's disease and major depressive disorder. However, their effects on cognitive function in healthy individuals is less established. Here, we explored the mitochondrial and performative outcomes of a novel eight-week ketone-supplemented ketogenic (KETO) diet in healthy adult male and female mice. In a novel object recognition test, KETO mice spent more time with the novel, compared to familiar, object, indicating an improvement in recognition memory. High-resolution respirometry on permeabilized hippocampal tissue returned significant reductions in mitochondrial O2 consumption. No changes in ATP production were observed, yielding a significantly higher ATP:O2 ratio, a measure of mitochondrial efficiency. Together, these findings demonstrate the KETO diet improves hippocampal mitochondrial efficiency. They add to a growing body of evidence that suggests ketones and ketogenic diets are neuroprotective and metabolically and cognitively relevant, even in healthy adults. They also suggest that ketogenic lifestyle changes may be effective strategies for protecting against cognitive decline associated with aging and disease.

The Role of Diet and Dietary Patterns in Parkinson's Disease

Parkinson's Disease (PD) is a neurodegenerative disorder associated with diminished nutrition status and decreased quality of life. While the prevalence of PD is expected to increase, no preventative or curative therapy for PD exists at this time. Although nutrition and diet represent modifiable risk factors for reducing chronic disease risk, research on the impact of single nutrients on PD has yielded mixed results. As a result, this single-nutrient approach may be the driving force behind the inconsistency, and a holistic dietary approach may overcome this inconsistency by accounting for the interactions between nutrients. The following review aims to examine the impact of a generally healthy dietary pattern, the protein-restricted diet (PRD), the ketogenic diet (KD), the Mediterranean diet (MD), and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet on PD risk, progression, and severity. While most of the included studies support the role of diet and dietary patterns in reducing the risk of PD or alleviating PD severity, the inconsistent results and need for further evidence necessitate more research being conducted before making dietary recommendations. Research on the potential beneficial effects of dietary patterns on PD should also investigate potential risks.

Does Neuroinflammation Underlie the Cognitive Changes Observed With Dietary Interventions?

Dietary interventions, such as calorie restriction and ketogenic diet, have been extensively studied in ageing research, including in cognitive decline. Epidemiological studies indicate beneficial effects of certain dietary regimes on mental health, including mood disorders and dementia. However, randomised-controlled trials (the gold-standard of evidence-based medicine) on calorie restriction diets and the ketogenic diet have yet to show clinically convincing effects in neuropsychiatric disorders. This review will examine the quality of studies and evidence base for the ketogenic and calorie restriction diets in common neuropsychiatric conditions, collating findings from preclinical experiments, case reports or small clinical studies, and randomised controlled clinical trials. The major cellular mechanisms that mediate the effects of these dietary interventions on brain health include neuroinflammation, neuroprotection, and neuromodulation. We will discuss the studies that have investigated the roles of these pathways and their interactions. Popularity of the ketogenic and calorie restriction diets has grown both in the public domain and in psychiatry research, allowing for informed review of the efficacy, the limitations, and the side effects of these diets in specific patient populations. In this review we will summarise the clinical evidence for these diets in neuropsychiatry and make suggestions to improve clinical translation of future research studies.

Genetically modified mice for research on human diseases: A triumph for Biotechnology or a work in progress?

Genetically modified mice are engineered as models for human diseases. These mouse models include inbred strains, mutants, gene knockouts, gene knockins, and ‘humanized’ mice. Each mouse model is engineered to mimic a specific disease based on a theory of the genetic basis of that disease. For example, to test the amyloid theory of Alzheimer’s disease, mice with amyloid precursor protein genes are engineered, and to test the tau theory, mice with tau genes are engineered. This paper discusses the importance of mouse models in basic research, drug discovery, and translational research, and examines the question of how to define the “best” mouse model of a disease. The critiques of animal models and the caveats in translating the results from animal models to the treatment of human disease are discussed. Since many diseases are heritable, multigenic, age-related and experience-dependent, resulting from multiple gene-gene and gene-environment interactions, it will be essential to develop mouse models that reflect these genetic, epigenetic and environmental factors from a developmental perspective. Such models would provide further insight into disease emergence, progression and the ability to model two-hit and multi-hit theories of disease. The summary examines the biotechnology for creating genetically modified mice which reflect these factors and how they might be used to discover new treatments for complex human diseases such as cancers, neurodevelopmental and neurodegenerative diseases.

Comparison of the Impact of the Mediterranean Diet, Anti-Inflammatory Diet, Seventh-Day Adventist Diet, and Ketogenic Diet Relative to Cognition and Cognitive Decline

PURPOSE OF REVIEW

Increasing evidence points toward the importance of diet and its impact on cognitive decline. This review seeks to clarify the impact of four diets on cognition: the Mediterranean diet, the anti-inflammatory diet, the Seventh Day Adventist diet, and the Ketogenic diet.

RECENT FINDINGS

Of the diets reviewed, the Mediterranean diet provides the strongest evidence for efficacy. Studies regarding the anti-inflammatory diet and Seventh Day Adventist diet are sparse, heterogeneous in quality and outcome measurements, providing limited reliable data. There is also minimal research confirming the cognitive benefits of the Ketogenic diet. Increasing evidence supports the use of the Mediterranean diet to reduce cognitive decline. The MIND-diet, a combination of the Mediterranean and DASH diets, seems especially promising, likely due to its anti-inflammatory properties. The Ketogenic diet may also have potential efficacy; however, adherence in older populations may be difficult given frequent adverse effects. Future research should focus on long-term, well-controlled studies confirming the impact of various diets, as well as the combination of diets and lifestyle modification.

Can dietary patterns prevent cognitive impairment and reduce Alzheimer's disease risk: exploring the underlying mechanisms of effects

Alzheimer's disease (AD) is one of the fastest growing cognitive decline-related neurological diseases. To date, effective curative strategies have remained elusive. A growing body of evidence indicates that dietary patterns have significant effects on cognitive function and the risk of developing AD. Previous studies on the association between diet and AD risk have mainly focused on individual food components and specific nutrients, and the mechanisms responsible for the beneficial effects of dietary patterns on AD are not well understood. This article provides a comprehensive overview of the effects of dietary patterns, including the Mediterranean diet (MedDiet), dietary approaches to stop hypertension (DASH) diet, Mediterranean-DASH diet intervention for neurological delay (MIND), ketogenic diet, caloric restriction, intermittent fasting, methionine restriction, and low-protein and high-carbohydrate diet, on cognitive impairment and summarizes the underlying mechanisms by which dietary patterns attenuate cognitive impairment, especially highlighting the modulation of dietary patterns on cognitive impairment through gut microbiota. Furthermore, considering the variability in individual metabolic responses to dietary intake, we put forward a framework to develop personalized dietary patterns for people with cognitive disorders or AD based on individual gut microbiome compositions.

Feasibility of an MI-CBT ketogenic adherence program for older adults with mild cognitive impairment

BACKGROUND

The National Institutes of Health Obesity-Related Behavioral Intervention Trials model for intervention development was used to establish the feasibility and proof of concept of a motivational ketogenic nutrition adherence program for older adults with mild cognitive impairment.

METHODS

This was a single-arm, single-center feasibility trial. A comprehensive assessment protocol, including a clinical interview, neuropsychological testing, and genetic sequencing was used as an initial screening. Nine participants (aged 64-75) with possible amnestic mild cognitive impairment were consented for the intervention. Participants completed pre- and post-intervention neuropsychological assessments using the updated Repeatable Battery for Assessment of Neuropsychological Status. Participants tracked their macronutrient consumption using food diaries and ketone levels using urinalysis test strips daily. Mood and other psychosocial variables were collected through surveys, and qualitative exit interviews were completed.

RESULTS

100% of participants who began the trial completed the 6-week ketogenic nutrition adherence program, including completion of the pre- and post-assessments. Eight participants achieved measurable levels of ketones during the program. The average self-rated adherence across the program was 8.7 out of 10. A Wilcoxon Signed-Rank test demonstrated significant improvement in cognitive performance from baseline (median = 88) to follow up (median = 96, Z = - 2.26, p = .024). The average difference in cognitive performance from baseline to follow-up was - 7.33 (95% CI - 12.85, - 1.82).

CONCLUSIONS

Results supported the feasibility for moving to the next phase and demonstrated proof of concept for the intervention. The next step is a randomized pilot trial to test clinical signals of effect compared to a control condition.

TRIAL REGISTRATION

This trial was retrospectively registered with clinicaltrials.gov on July 13, 2021. The trial number is NCT04968041.

Efficacy and Safety of Ketone Supplementation or Ketogenic Diets for Alzheimer's Disease: A Mini Review

Alzheimer's disease (AD) is the most frequent age-related neurodegenerative disorder, with no curative treatment available so far. Alongside the brain deposition of β-amyloid peptide and hyperphosphorylated tau, neuroinflammation triggered by the innate immune response in the central nervous system, plays a central role in the pathogenesis of AD. Glucose usually represents the main fuel for the brain. Glucose metabolism has been related to neuroinflammation, but also with AD lesions. Hyperglycemia promotes oxidative stress and neurodegeneration. Insulinoresistance (e.g., in type 2 diabetes) or low IGF-1 levels are associated with increased β-amyloid production. However, in the absence of glucose, the brain may use another fuel: ketone bodies (KB) produced by oxidation of fatty acids. Over the last decade, ketogenic interventions i.e., ketogenic diets (KD) with very low carbohydrate intake or ketogenic supplementation (KS) based on medium-chain triglycerides (MCT) consumption, have been studied in AD animal models, as well as in AD patients. These interventional studies reported interesting clinical improvements in animals and decrease in neuroinflammation, β-amyloid and tau accumulation. In clinical studies, KS and KD were associated with better cognition, but also improved brain metabolism and AD biomarkers. This review summarizes the available evidence regarding KS/KD as therapeutic options for individuals with AD. We also discuss the current issues and potential adverse effects associated with these nutritional interventions. Finally, we propose an overview of ongoing and future registered trials in this promising field.

Mitochondria-Microbiota Interaction in Neurodegeneration

Alzheimer’s and Parkinson’s are the two best-known neurodegenerative diseases. Each is associated with the excessive aggregation in the brain and elsewhere of its own characteristic amyloid proteins. Yet the two afflictions have much in common and often the same amyloids play a role in both. These amyloids need not be toxic and can help regulate bile secretion, synaptic plasticity, and immune defense. Moreover, when they do form toxic aggregates, amyloids typically harm not just patients but their pathogens too. A major port of entry for pathogens is the gut. Keeping the gut’s microbe community (microbiota) healthy and under control requires that our cells’ main energy producers (mitochondria) support the gut-blood barrier and immune system. As we age, these mitochondria eventually succumb to the corrosive byproducts they themselves release, our defenses break down, pathogens or their toxins break through, and the side effects of inflammation and amyloid aggregation become problematic. Although it gets most of the attention, local amyloid aggregation in the brain merely points to a bigger problem: the systemic breakdown of the entire human superorganism, exemplified by an interaction turning bad between mitochondria and microbiota.

Can Ketogenic Diet Improve Alzheimer's Disease? Association With Anxiety, Depression, and Glutamate System

Background: Alzheimer's disease is the most common neurodegenerative disorder in our society, mainly characterized by loss of cognitive function. However, other symptoms such as anxiety and depression have been described in patients. The process is mediated by alterations in the synaptic and extrasynaptic activity of the neurotransmitter glutamate, which are linked to a hypometabolism of glucose as the main source of brain energy. In that respect, Ketogenic diet (KD) has been proposed as a non-pharmacological treatment serving as an alternative energy source to the neurons increasing the fat percentage and reducing the carbohydrates percentage, showing promising results to improve the cognitive symptoms associated with different neurodegenerative disorders, including AD. However, the association of this type of diet with emotional symptoms and the modulation of glutamate neurotransmission systems after this dietary reduction of carbohydrates are unknown.

Objective: The aim of this short review is to provide update studies and discuss about the relationship between KD, anxiety, depression, and glutamate activity in AD patients.

Discussion: The main results suggest that the KD is an alternative energy source for neurons in AD with positive consequences for the brain at different levels such as epigenetic, metabolic and signaling, and that the substitution of carbohydrates for fats is also associated with emotional symptoms and glutamate activity in AD.

Benefits of Low Carbohydrate Diets: a Settled Question or Still Controversial?

PURPOSE OF REVIEW

The purpose of this review was to provide an update on the available data on the benefits of low-carbohydrate (low-carb) diets for weight management and type 2 diabetes (T2DM) and determine if low-carb diets were a settled question or still controversial.

RECENT FINDINGS

Most of the recent published literature in this area consists of reviews of past trials, with a relatively smaller number of recent trials. Low-carb is most commonly compared to low-fat, with problematically inconsistent definitions of both. There are numerous challenges in trying to draw clear conclusions about efficacy and effectiveness. Short-term vs. long-term effects can differ, which is likely impacted by adherence. Adherence is very different between metabolic chamber or feeding studies vs. free-living. Body weight alone is a crude measure that fails to capture potentially important differences in lean-mass, fat-mass, and body water. Benefits for glycemic control need to be balanced with impacts on non-glycemic outcomes such as LDL-cholesterol, the microbiome, and inflammation. It is important to differentiate between low-carb and very-low carbohydrate diets (VLCD). To date no large-scale long-term clinical trials have been conducted testing whether low-carb diets can prevent T2DM. Many issues regarding benefits and risks of low-carb diets remain controversial or unresolved, particularly for VLCD. Some of the recent, better studies highlighted in this review suggest strategies for resolving these controversies.

GABAA receptor agonist muscimol rescues inhibitory microcircuit defects in the olfactory bulb and improves olfactory function in APP/PS1 transgenic mice

Olfactory damage develops at the early stages of Alzheimer's disease (AD). While amyloid-β (Aβ) oligomers are shown to impair inhibitory circuits in the olfactory bulb (OB), its underlying mechanisms remain unclear. Here, we investigated the olfactory dysfunction due to impaired inhibitory transmission to mitral cells (MCs) of the OB in APP/PS1 mice. Using electrophysiological studies, we found that MCs exhibited increased spontaneous firing rates as early as 3 months, much before development of Aβ deposits in the brain. Furthermore, the frequencies but not amplitudes of MC inhibitory postsynaptic currents decreased markedly, suggesting that presynaptic GABA release is impaired while postsynaptic GABA_A receptor responses remain intact. Notably, muscimol, a GABA_A receptor agonist, improved odor identification and discrimination behaviors in APP/PS1 mice, reduced MC basal firing activity, and rescued inhibitory circuits along with reducing the Aβ burden in the OB. Our study links the presynaptic deficits of GABAergic transmission to olfactory dysfunction and subsequent AD development and implicates the therapeutic potential of maintaining local inhibitory microcircuits against early AD progression.

Ketogenic Diets and Chronic Disease: Weighing the Benefits Against the Risks

Very-low-carbohydrate ketogenic diets have been long been used to reduce seizure frequency and more recently have been promoted for a variety of health conditions, including obesity, diabetes, and liver disease. Ketogenic diets may provide short-term improvement and aid in symptom management for some chronic diseases. Such diets affect diet quality, typically increasing intake of foods linked to chronic disease risk and decreasing intake of foods found to be protective in epidemiological studies. This review examines the effects of ketogenic diets on common chronic diseases, as well as their impact on diet quality and possible risks associated with their use. Given often-temporary improvements, unfavorable effects on dietary intake, and inadequate data demonstrating long-term safety, for most individuals, the risks of ketogenic diets may outweigh the benefits.

Ketogenic diet therapy in Alzheimer's disease: an updated review

PURPOSE OF REVIEW

Ketogenic diets (KD) are validated treatments of pharmacoresistant epilepsy. Their interest in neurodegenerative diseases such as Alzheimer's disease (AD) has been suggested, because ketone bodies may reduce neuroinflammation, improve neurotransmitters transport pathway, synaptic maintenance, and reduce brain β-amyloid deposition. In this updated review, we aimed at critically examining the evidence of the past 2 years regarding KD or ketogenic supplements (KS) on cognitive and biological/neuropathological outcomes. We conducted our search in preclinical studies (animal models of AD) or in humans with or without cognitive impairment.

RECENT FINDINGS

Overall, 12 studies were included: four in animal models of AD and eight in humans. In preclinical studies, we found additional evidence for a decrease in cerebral inflammation as well as in specific features of AD: β-amyloid, aggregates of tau protein under KD/KS. Several AD mouse models experienced clinical improvements. Human studies reported significant cognitive benefits, improved brain metabolism and biomarkers change under KD/KS, despite rather short-term interventions. Adherence to KD or KS was acceptable with frequent, but minor gastrointestinal adverse effects.

SUMMARY

The present review gathered additional evidence for both pathophysiological and clinical benefits of KS/KD in AD. Further studies are warranted with a biomarker-based selection of AD participants and long-term follow-up.

High-throughput LC-MS method to investigate postprandial lipemia: considerations for future precision nutrition research

Elevated postprandial lipemia is an independent risk factor for cardiovascular disease, yet methods to quantitate postmeal handling of dietary lipids in humans are limited. This study tested a new method to track dietary lipid appearance using a stable isotope tracer (²H₁₁-oleate) in liquid meals containing three levels of fat [low fat (LF), 15 g; moderate fat (MF), 30 g; high fat (HF), 60 g]. Meals were fed to 12 healthy men [means ± SD, age 31.3 ± 9.2 yr, body mass index (BMI) 24.5 ± 1.9 kg/m²] during four randomized study visits; the HF meal was administered twice for reproducibility. Blood was collected over 8 h postprandially, triglyceride (TG)-rich lipoproteins (TRL), and particles with a Svedberg flotation rate >400 (S_f > 400, n = 8) were isolated by ultracentrifugation, and labeling of two TG species (54:3 and 52:2) was quantified by LC-MS. Total plasma TRL-TG concentrations were threefold greater than S_f > 400-TG. Both S_f > 400- and TRL-TG 54:3 were present at higher concentrations than 52:2, and singly labeled TG concentrations were higher than doubly labeled. Furthermore, TG 54:3 and the singly labeled molecules demonstrated higher plasma absolute entry rates differing significantly across fat levels within a single TG species (P < 0.01). Calculation of fractional entry showed no significant differences in label handling supporting the utility of either TG species for appearance rate calculations. These data demonstrate the utility of labeling research meals with stable isotopes to investigate human postprandial lipemia while simultaneously highlighting the importance of examining individual responses. Meal type and timing, control of prestudy activities, and effects of sex on outcomes should match the research goals. The method, optimized here, will be beneficial to conduct basic science research in precision nutrition and clinical drug development.NEW & NOTEWORTHY A novel method to test human intestinal lipid handling using stable isotope labeling is presented and, for the first time, plasma appearance and lipid turnover were quantified in 12 healthy men following meals with varying amounts of fat. The method can be applied to studies in precision nutrition characterizing individual response to support basic science research or drug development. This report discusses key questions for consideration in precision nutrition that were highlighted by the data.

Therapies for Alzheimer's disease: a metabolic perspective

Alzheimer's disease (AD) is one of the most common forms of dementia in the elderly. Currently, there are over 50 million cases of dementia worldwide and it is expected that it will reach 136 million by 2050. AD is described as a neurodegenerative disease that gradually compromises memory and learning capacity. Patients often exhibit brain glucose hypometabolism and are more susceptible to develop type 2 diabetes or insulin resistance in comparison with age-matched controls. This suggests that there is a link between both pathologies. Glucose metabolism and the tricarboxylic acid cycle are tightly related to mitochondrial performance and energy production. Impairment of both these pathways can evoke oxidative damage on mitochondria and key proteins linked to several hallmarks of AD. Glycation is also another type of post-translational modification often reported in AD, which might impair the function of proteins that participate in metabolic pathways thought to be involved in this illness. Despite needing further research, therapies based on insulin treatment, usage of anti-diabetes drugs or some form of dietary intervention, have shown to be promising therapeutic approaches for AD in its early stages of progression and will be unveiled in this paper.

Effect of the ketogenic diet in excitable tissues

In the past decade, ketogenic diet (KD) has gained some popularity as a potential treatment for a wide range of diseases, including neurological and metabolic disorders, thanks to a beneficial role mainly related to its anti-inflammatory properties. The high-fat and carbohydrate-restricted regimen causes changes in the metabolism, leading, through the β-oxidation of fatty acids, to the hepatic production of ketone bodies (KBs), which are used by many extrahepatic tissues as energy fuels. Once synthetized, KBs are delivered through the systemic circulation to all the tissues of the organism, where they play pleiotropic roles acting directly and indirectly on various targets, and among them ion channels and neurotransmitters. Moreover, they can operate as signaling metabolites and epigenetic modulators. Therefore, it is inappropriate to consider that the KD regimen can improve the patients' clinical condition simply by means of specific and localized effects; rather, it is more correct to think that KBs affect the organism as a whole. In this review, we tried to summarize the recent knowledge of the effects of KBs on various tissues, with a particular attention on the excitable ones, namely the nervous system, heart, and muscles.

Importance of lipids for upper motor neuron health and disease

Building evidence reveals the importance of maintaining lipid homeostasis for the health and function of neurons, and upper motor neurons (UMNs) are no exception. UMNs are critically important for the initiation and modulation of voluntary movement as they are responsible for conveying cerebral cortex' input to spinal cord targets. To maintain their unique cytoarchitecture with a prominent apical dendrite and a very long axon, UMNs require a stable cell membrane, a lipid bilayer. Lipids can act as building blocks for many biomolecules, and they also contribute to the production of energy. Therefore, UMNs require sustained control over the production, utilization and homeostasis of lipids. Perturbations of lipid homeostasis lead to UMN vulnerability and progressive degeneration in diseases such as hereditary spastic paraplegia (HSP) and primary lateral sclerosis (PLS). Here, we discuss the importance of lipids, especially for UMNs.

Modulation of Brain Hyperexcitability: Potential New Therapeutic Approaches in Alzheimer's Disease

People with Alzheimer's disease (AD) have significantly higher rates of subclinical and overt epileptiform activity. In animal models, oligomeric Aβ amyloid is able to induce neuronal hyperexcitability even in the early phases of the disease. Such aberrant activity subsequently leads to downstream accumulation of toxic proteins, and ultimately to further neurodegeneration and neuronal silencing mediated by concomitant tau accumulation. Several neurotransmitters participate in the initial hyperexcitable state, with increased synaptic glutamatergic tone and decreased GABAergic inhibition. These changes appear to activate excitotoxic pathways and, ultimately, cause reduced long-term potentiation, increased long-term depression, and increased GABAergic inhibitory remodelling at the network level. Brain hyperexcitability has therefore been identified as a potential target for therapeutic interventions aimed at enhancing cognition, and, possibly, disease modification in the longer term. Clinical trials are ongoing to evaluate the potential efficacy in targeting hyperexcitability in AD, with levetiracetam showing some encouraging effects. Newer compounds and techniques, such as gene editing via viral vectors or brain stimulation, also show promise. Diagnostic challenges include identifying best biomarkers for measuring sub-clinical epileptiform discharges. Determining the timing of any intervention is critical and future trials will need to carefully stratify participants with respect to the phase of disease pathology.