Link between cancer and Alzheimer disease via oxidative stress induced by nitric oxide-dependent mitochondrial DNA overproliferation and deletion

Signaling Pathways Concerning Mitochondrial Dysfunction: Implications in Neurodegeneration and Possible Molecular Targets

Mitochondrion is an important organelle present in our cells responsible for meeting energy requirements. All higher organisms rely on efficient mitochondrial bioenergetic machinery to sustain life. No other respiratory process can produce as much power as generated by mitochondria in the form of ATPs. This review is written in order to get an insight into the magnificent working of mitochondrion and its implications in cellular homeostasis, bioenergetics, redox, calcium signaling, and cell death. However, if this machinery gets faulty, it may lead to several disease states. Mitochondrial dysfunctioning is of growing concern today as it is seen in the pathogenesis of several diseases which includes neurodegenerative disorders, cardiovascular disorders, diabetes mellitus, skeletal muscle defects, liver diseases, and so on. To cover all these aspects is beyond the scope of this article; hence, our study is restricted to neurodegenerative disorders only. Moreover, faulty functioning of this organelle can be one of the causes of early ageing in individuals. This review emphasizes mutations in the mitochondrial DNA, defects in oxidative phosphorylation, generation of ROS, and apoptosis. Researchers have looked into new approaches that might be able to control mitochondrial failure and show a lot of promise as treatments.

Oleic acid reduces oxidative stress in rat brain induced by some anticancer drugs

Oleic acid (OA) is a monounsaturated compound with many health-benefitting properties such as obesity prevention, increased insulin sensitivity, antihypertensive and immune-boosting properties, etc. The aim of this study was to analyze the effect of oleic acid (OA) and some anticancer drugs against oxidative damage induced by nitropropionic acid (NPA) in rat brain. Six groups of Wistar rats were treated as follows: Group 1, (control); group 2, OA; group 3, NPA + OA; group 4, cyclophosphamide (CPP) + OA; group 5, daunorubicin (DRB) + OA; and group 6, dexrazoxane (DXZ) + OA. All compounds were administered intraperitoneally route, every 24 h for 5 days. Their brains were extracted to measure lipoperoxidation (TBARS), H2O2, Ca+2, Mg+2 ATPase activity, glutathione (GSH) and dopamine. Glucose, hemoglobin and triglycerides were measured in blood. In cortex GSH increased in all groups, except in group 2, the group 4 showed the highest increase of this biomarker. TBARS decrease, and dopamine increase in all regions of groups 4, 5 and 6. H2O2 increased only in cerebellum/medulla oblongata of group 5 and 6. ATPase expression decreased in striatum of group 4. Glucose increased in group 6, and hemoglobin increased in groups 4 and 5. These results suggest that the increase of dopamine and the antioxidant effect of oleic acid administration during treatment with oncologic agents could result in less brain injury.

Causal association between colorectal cancer and Alzheimer's disease: a bidirectional two-sample mendelian randomization study

Background: Colorectal cancer and Alzheimer's disease are both common life-threatening diseases in the elderly population. Some studies suggest a possible inverse relationship between colorectal cancer and Alzheimer's disease, but real-world research is subject to many biases. We hope to clarify the causal relationship between the two through a bidirectional two-sample Mendelian randomization study. Methods: In our study, we used genetic summary data from large-scale genome-wide association studies to investigate the relationship between colorectal cancer and Alzheimer's disease. Our primary analysis employed the inverse-variance weighted method and we also used complementary techniques, including MR-Egger, weighted median estimator, and Maximum likelihood. We applied simex adjustment to the MR-Egger results. We also utilized the MRlap package to detect potential sample overlap and its impact on the bias of the results. In addition, we performed several sensitivity and heterogeneity analyses, to ensure the reliability of our results. Results: The combined effect size results of the inverse-variance weighted method indicate that colorectal cancer may decrease the incidence of Alzheimer's disease, with an odds ratio (OR) of 0.846 (95% CI: 0.762-0.929). Similar results were observed using other methods such as MR-Egger, weighted median estimator, and Maximum likelihood. On the other hand, Alzheimer's disease may slightly increase the incidence of colorectal cancer, with an OR of 1.014 (95% CI: 1.001-1.027). However, the results of one subgroup were not significant, and the results from MRlap indicated that sample overlap introduced bias into the results. Therefore, the results of the reverse validation are not reliable. The F-statistic for all SNPs was greater than 20. Four SNPs related to the outcome were excluded using Phenoscanner website but the adjustment did not affect the overall direction of the results. The results of these statistics were further validated by MR-PRESSO, funnel plots, leave-one-out analyses, Cochran's Q, demonstrating the reliability of the findings. Conclusion: According to the findings of this Mendelian randomization study, there appears to be a causal association between colorectal cancer and Alzheimer's disease. These results could have important implications for clinical practice in terms of how colorectal cancer and Alzheimer's disease are treated. To better understand the relationship between these two diseases, more research and screening are needed in clinical settings.

Regulatory mechanism of icariin in cardiovascular and neurological diseases

Cardiovascular diseases (CVDs) and neurological diseases are widespread diseases with substantial rates of morbidity and mortality around the world. For the past few years, the preventive effects of Chinese herbal medicine on CVDs and neurological diseases have attracted a great deal of attention. Icariin (ICA), the main constituent of Epimedii Herba, is a flavonoid. It has been shown to provide neuroprotection, anti-tumor, anti-osteoporosis, and cardiovascular protection. The endothelial protection, anti-inflammatory, hypolipidemic, antioxidative stress, and anti-apoptosis properties of ICA can help stop the progression of CVDs and neurological diseases. Therefore, our review summarized the known mechanisms and related studies of ICA in the prevention and treatment of cardio-cerebrovascular diseases (CCVDs), to better understand its therapeutic potential.

Mitochondria: how eminent in ageing and neurodegenerative disorders?

Numerous factors are implicated in the onset and progression of ageing and neurodegenerative disorders, with defects in cell energy supply and free radicals regulation designated as being the main functions of mitochondria and highly accentuated in plentiful studies. Hence, analysing the role of mitochondria as one of the main factors implicated in these disorders could undoubtedly come in handy with respect to disease prevention and treatment. In this review, first, we will explore how mitochondria account for neurodegenerative disorders and ageing and later will draw the various pathways contributing to mitochondrial dysfunction in their distinct way. Also, we will discuss the deviation-countering mechanisms, particularly mitophagy, a subset of autophagy known as a much larger cellular defence mechanism and regulatory system, along with its potential therapeutic effects. Last but not least, we will be highlighting the mitochondrial transfer experiments with animal models of neurodegenerative disorders.

Natural Product Co-Metabolism and the Microbiota-Gut-Brain Axis in Age-Related Diseases

Complementary alternative medicine approaches are growing treatments of diseases to standard medicine practice. Many of these concepts are being adopted into standard practice and orthomolecular medicine. Age-related diseases, in particular neurodegenerative disorders, are particularly difficult to treat and a cure is likely a distant expectation for many of them. Shifting attention from pharmaceuticals to phytoceuticals and "bugs as drugs" represents a paradigm shift and novel approaches to intervention and management of age-related diseases and downstream effects of aging. Although they have their own unique pathologies, a growing body of evidence suggests Alzheimer's disease (AD) and vascular dementia (VaD) share common pathology and features. Moreover, normal metabolic processes contribute to detrimental aging and age-related diseases such as AD. Recognizing the role that the cerebral and cardiovascular pathways play in AD and age-related diseases represents a common denominator in their pathobiology. Understanding how prosaic foods and medications are co-metabolized with the gut microbiota (GMB) would advance personalized medicine and represents a paradigm shift in our view of human physiology and biochemistry. Extending that advance to include a new physiology for the advanced age-related diseases would provide new treatment targets for mild cognitive impairment, dementia, and neurodegeneration and may speed up medical advancements for these particularly devastating and debilitating diseases. Here, we explore selected foods and their derivatives and suggest new dementia treatment approaches for age-related diseases that focus on reexamining the role of the GMB.

Redox balance and autophagy regulation in cancer progression and their therapeutic perspective

Cellular ROS production participates in various cellular functions but its accumulation decides the cell fate. Malignant cells have higher levels of ROS and active antioxidant machinery, a characteristic hallmark of cancer with an outcome of activation of stress-induced pathways like autophagy. Autophagy is an intracellular catabolic process that produces alternative raw materials to meet the energy demand of cells and is influenced by the cellular redox state thus playing a definite role in cancer cell fate. Since damaged mitochondria are the main source of ROS in the cell, however, cancer cells remove them by upregulating the process of mitophagy which is known to play a decisive role in tumorigenesis and tumor progression. Chemotherapy exploits cell machinery which results in the accumulation of toxic levels of ROS in cells resulting in cell death by activating either of the pathways like apoptosis, necrosis, ferroptosis or autophagy in them. So understanding these redox and autophagy regulations offers a promising method to design and develop new cancer therapies that can be very effective and durable for years. This review will give a summary of the current therapeutic molecules targeting redox regulation and autophagy for the treatment of cancer. Further, it will highlight various challenges in developing anticancer agents due to autophagy and ROS regulation in the cell and insights into the development of future therapies.

Polyphenols and Small Phenolic Acids as Cellular Metabolic Regulators

Polyphenols and representative small phenolic acids and molecules derived from larger constituents are dietary antioxidants from fruits, vegetables and largely other plant-based sources that have ability to scavenge free radicals. What is often neglected in polyphenol metabolism is bioavailability and the role of the gut microbiota (GMB), which has an essential role in health and disease and participates in co-metabolism with the host. The composition of the gut microbiota is in constant flux and is modified by multiple intrinsic and extrinsic factors, including antibiotics. Dietary or other factors are key modulators of the host gut milieu. In this review, we explore the role of polyphenols and select phenolic compounds as metabolic or intrinsic biochemistry regulators and explore this relationship in the context of the microbiota–gut–target organ axis in health and disease.

Associations of ARHGAP26 Polymorphisms with Alzheimer's Disease and Cardiovascular Disease

The Rho GTPase activating protein 26 (ARHGAP26) gene has been reported to be associated with neuropsychiatric diseases and neurodegenerative diseases including Parkinson's disease. We examined whether the ARHGAP26 gene is associated with Alzheimer's disease (AD) and/or cardiovascular disease (CVD). Multivariable logistic regression model was used to examine the associations of 154 single nucleotide polymorphisms (SNPs) within the ARHGAP26 gene with AD and CVD using the Alzheimer's Disease Neuroimaging Initiative 1 (ADNI-1) cohort. Fourteen SNPs were associated with AD (top SNP rs3776362 with p = 3.43 × 10^-3), while 37 SNPs revealed associations with CVD (top SNP rs415235 with p = 2.06 × 10^-4). Interestingly, 13 SNPs were associated with both AD and CVD. SNP rs3776362 was associated with CVD, Functional Activities Questionnaire (FAQ), and Clinical Dementia Rating Sum of Boxes (CDR-SB). A replication study using a Caribbean Hispanics sample showed that 17 SNPs revealed associations with AD, and 12 SNPs were associated with CVD. The third sample using a family-based study design showed that 9 SNPs were associated with AD, and 3 SNPs were associated with CVD. SNP rs6836509 within the ARHGAP10 gene (an important paralogon of ARHGAP26) was associated with AD and cerebrospinal fluid total tau (t-tau) level in the ADNI sample. Several SNPs were functionally important using the RegulomeDB, while a number of SNPs were associated with significant expression quantitative trait loci (eQTLs) using Genotype-Tissue Expression (GTEx) databases. In conclusion, genetic variants within ARHGAP26 were associated with AD and CVD. These findings add important new insights into the potentially shared pathogenesis of AD and CVD.

Inverse Correlation Between Alzheimer's Disease and Cancer: Short Overview

The negative association between Alzheimer's disease (AD) and cancer suggests that susceptibility to one disease may protect against the other. When biological mechanisms of AD and cancer and relationship between them are understood, the unsolved problem of both diseases which still touches the growing human population could be overcome. Actual information about biological mechanisms and common risk factors such as chronic inflammation, age-related metabolic deregulation, and family history is presented here. Common signaling pathways, e.g., p53, Wnt, role of Pin1, and microRNA, are discussed as well. Much attention is also paid to the potential impact of chronic viral, bacterial, and fungal infections that are responsible for the inflammatory pathway in AD and also play a key role to cancer development. New data about common mechanisms in etiopathology of cancer and neurological diseases suggests new therapeutic strategies. Among them, the use of nilotinib, tyrosine kinase inhibitor, protein kinase C, and bexarotene is the most promising.

Mitochondrion as a Selective Target for the Treatment of Atherosclerosis: Role of Mitochondrial DNA Mutations and Defective Mitophagy in the Pathogenesis of Atherosclerosis and Chronic Inflammation

BACKGROUND

Atherosclerosis is a chronic inflammatory condition that affects different arteries in the human body and often leads to severe neurological complications, such as stroke and its sequelae. Affected blood vessels develop atherosclerotic lesions in the form of focal thickening of the intimal layer, so called atherosclerotic plaques.

OBJECTIVES

Despite the high priority of atherosclerosis research for global health and the numerous preclinical and clinical studies conducted, currently, there is no effective pharmacological treatment that directly impacts atherosclerotic plaques. Many knowledge gaps exist in our understanding of the mechanisms of plaque formation. In this review, we discuss the role of mitochondria in different cell types involved in atherogenesis and provide information about mtDNA mutations associated with the disease.

RESULTS

Mitochondria of blood and arterial wall cells appear to be one of the important factors in disease initiation and development. Significant experimental evidence connects oxidative stress associated with mitochondrial dysfunction and vascular disease. Moreover, mitochondrial DNA (mtDNA) deletions and mutations are being considered as potential disease markers. Further study of mtDNA damage and associated dysfunction may open new perspectives for atherosclerosis treatment.

CONCLUSION

Mitochondria can be considered as important disease-modifying factors in several chronic pathologies. Deletions and mutations of mtDNA may be used as potential disease markers. Mitochondria-targeting antioxidant therapies appear to be promising for the development of treatment of atherosclerosis and other diseases associated with oxidative stress and chronic inflammation.

Health Science Community Will Miss This Bright and Uniting Star: In Memory of Professor Gjumrakch Aliev, M.D, Ph.D

It is with deep sadness that we offer our memorial on the unexpected demise of our dear colleague, Professor Gjumrakch Aliev [...].

Changes of Mineralogical Properties and Biological Activities of Gypsum and Its Calcined Products with Different Phase Structures

Raw gypsum (RG) and calcined gypsum (CG) are widely used in traditional Chinese medicine (TCM). RG is usually taken orally to resolve heat and diminish inflammation, while CG is only used externally to treat ulcerations and empyrosis. Calcination at different temperatures, three phase CG structures, namely, bassanite, anhydrite III, and anhydrite II, may be generated. We herein investigated the relationship between the phase structure and the efficacy of CG and the optimum phase structure for CG. RG has a compact structure, small pore size, weak anti-inflammatory effect, but no antibacterial effect, and has almost no effect on the repair of scalds. CG150 (bassanite) has a loose texture, large pore size and specific surface area, and certain antibacterial and anti-inflammatory effects, but it has a poor repair effect on scalds. CG750 (anhydrite II) has a compact structure, small pore size and specific surface area, and low antibacterial and anti-inflammatory effects, but it has a certain repair effect on scalds. Only CG350 (anhydrite III) has good performance in texture, pore size, specific surface area, antibacterial, anti-inflammatory, and scald repair. Our research has proved that the mineral properties and biological activities of CG are different due to different phase structures. CG350, namely, anhydrite III, is considered by our research to be the optimal phase structure as CG.

Dual Action of Dipyridothiazine and Quinobenzothiazine Derivatives-Anticancer and Cholinesterase-Inhibiting Activity

The inverse correlation observed between Alzheimer’s disease (AD) and cancer has prompted us to look for cholinesterase-inhibiting activity in phenothiazine derivatives that possess anticancer properties. With the use of in silico and in vitro screening methods, our study found a new biological activity in anticancer polycyclic, tricyclic, and tetracyclic compounds. The virtual screening of a library of 120 ligands, which are the derivatives of azaphenothiazine, led to the identification of 25 compounds that can act as potential inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Biological assays revealed the presence of selective inhibitors of eeAChE (electric eel AChE) or eqBuChE (equine serum BuChE) and nonselective inhibitors of both enzymes among the tested compounds. Their potencies against eeAChE were in a submicromolar-to-micromolar range with IC₅₀ values from 0.78 to 19.32 μM, while their IC₅₀ values against eqBuChE ranged from 0.46 to 10.38 μM. The most potent among the compounds tested was the tetracyclic derivative, 6-(4-diethylaminobut-2-ynyl)-9-methylthioquinobenzothiazine 24, which was capable of inhibiting both enzymes. 9-Fluoro-6-(1-piperidylethyl)quinobenzothiazine 23 was found to act as a selective inhibitor of eqBuChE with an IC₅₀ value of 0.46 μM. Compounds with such a dual antitumor and cholinesterase-inhibitory activity can be considered as a valuable combination for the treatment of both cancer and AD prevention. The results presented in this study might open new directions of research on the group of tricyclic phenothiazine derivatives.

The Microbiota-Gut-Brain Axis-Heart Shunt Part II: Prosaic Foods and the Brain-Heart Connection in Alzheimer Disease

There is a strong cerebrovascular component to brain aging, Alzheimer disease, and vascular dementia. Foods, common drugs, and the polyphenolic compounds contained in wine modulate health both directly and through the gut microbiota. This observation and novel findings centered on nutrition, biochemistry, and metabolism, as well as the newer insights we gain into the microbiota-gut-brain axis, now lead us to propose a shunt to this classic triad, which involves the heart and cerebrovascular systems. The French paradox and prosaic foods, as they relate to the microbiota-gut-brain axis and neurodegenerative diseases, are discussed in this manuscript, which is the second part of a two-part series of concept papers addressing the notion that the microbiota and host liver metabolism all play roles in brain and heart health.

Folic acid increases levels of GHS in brain of rats with oxidative stress induced with 3-nitropropionic acid

Aim: This study tested the hypothesis that folic acid (FA) modulates biogenic amines and protects the brain against oxidative stress induced by 3-nitropropionic acid (3NPA).Methods: Male Wistar rats received (groups of six) for 5 d: FA (50 mg/kg); 3NPA (10 mg/kg); or FA +3NPA. At last day, rats were sacrificed, and their brain was obtained to measure the levels of dopamine, 5-hydroxiindol acetic acid (5-HIAA). Reduced glutathione (GSH), total ATPase, H₂O₂ and lipid peroxidation were measured.Results: GSH increased significantly in cortex of rats treated with FA. ATPase increased significantly in cerebellum/medulla oblongata and decreased in cortex of animal treated with 3NPA. 5-HIAA increased in striatum of rats that received 3NPA alone or combined with FA.Conclusion: 3NPA generates free radicals such effect can be counteracted with FA administration since this folate increases antioxidant capacity and modulates biogenic amines.

Future Therapeutic Perspectives into the Alzheimer's Disease Targeting the Oxidative Stress Hypothesis

Alzheimer's disease (AD) is a neurodegenerative disease that is usually accompanied by aging, increasingly being the most common cause of dementia in the elderly. This disorder is characterized by the accumulation of beta amyloid plaques (Aβ) resulting from impaired amyloid precursor protein (APP) metabolism, together with the formation of neurofibrillary tangles and tau protein hyperphosphorylation. The exacerbated production of reactive oxygen species (ROS) triggers the process called oxidative stress, which increases neuronal cell abnormalities, most often followed by apoptosis, leading to cognitive dysfunction and dementia. In this context, the development of new therapies for the AD treatment is necessary. Antioxidants, for instance, are promising species for prevention and treatment because they are capable of disrupting the radical chain reaction, reducing the production of ROS. These species have also proven to be adjunctive to conventional treatments making them more effective. In this sense, several recently published works have focused their attention on oxidative stress and antioxidant species. Therefore, this review seeks to show the most relevant findings of these studies.

The role of mitochondrial defects and oxidative stress in Alzheimer's disease

Alzheimer's disease (AD) is a complex, progressive, and irreversible neurodegenerative disorder. Recent reports suggest that it affects more than 36 million people worldwide and accounts 60-80% of all cases of dementia. It is characterised by aberrations of multiple interactive systems and pathways, which ultimately lead to memory loss and cognitive dysfunction. The exact mechanisms and initial triggering factors that underpin the known pathological defects in AD remain to be fully elucidated. In addition, an effective treatment strategy to reduce the progression of AD is yet to be achieved. In the light of above-mentioned facts, our article deals with the exploration of the mitochondrial defect and oxidative stress leading to this devastating disease. In this communication, we have highlighted specific mitochondrial and antioxidant-directed approach to ameliorate and manage AD. Nonetheless, new approaches should also be investigated that could tackle various molecular events involved in AD pathogenicity.

Dysfunction of mitochondria: Implications for Alzheimer's disease

Alzheimer's disease (AD), the most common form of dementia, is thought to be associated with multiple factors, where the greatest risk factor is aging. Several traditional views attribute the cause of AD to genetic heritability, reduced synthesis of the neurotransmitter acetylcholine, the accumulation of a toxic protein known as amyloid β (Aβ) peptide, and/or neurofibrillary tangles of hyperphosphorylated tau-protein, which affect microtubule stability. However, with several recent clinical trial failures involving billions of dollars of revenue, traditional views are being questioned more each day. New theories involving metabolic activity and mitochondrial dysfunction, which proposes that altered mitochondria are the driving force for the development of AD, are being examined and investigated more critically. Understanding mitochondrial dysfunction and therapeutically targeting mitochondrial bioenergetics in AD could be a novel treatment approach holding great promise for preventing and/or slowing the onset of AD.

Riboflavin and pyridoxine restore dopamine levels and reduce oxidative stress in brain of rats

BACKGROUND

Neurological disorders suggest that the excitotoxicity involves a drastic increase in intracellular Ca2+ concentrations and the formation of reactive oxygen species. The presence of these free radicals may also affect the dopaminergic system. The aim of this work was to determine if riboflavin (B2) and pyridoxine (B6) provide protection to the brain against free radicals generated by 3-nitropropionic acid (3-NPA) by measuring the levels of dopamine (DA) and selected oxidative stress markers.

METHODS

Male Fisher rats were grouped (n = 6) and treated as follows: group 1, control (NaCl 0.9%); group 2, 3-NPA (20 mg/kg); group 3, B2 (10 mg/kg); group 4, B2 (10 mg/kg) + 3-NPA (20 mg/kg); group 5, B6 (10 mg/kg) and group 6, B6 + 3-NPA. All treatments were administered every 24 h for 5 days by intraperitoneal route. After sacrifice, the brain was obtained to measure DA, GSH, and lipid peroxidation, Ca2+, Mg2+, ATPase and H2O2.

MAIN FINDINGS

Levels of dopamine increased in cortex, striatum and cerebellum/medulla oblongata of animals that received 3-NPA alone. The lipid peroxidation increased in cortex, striatum, and cerebellum/medulla oblongata, of animals treated with B2 vitamin alone. ATPase dependent on Ca+2, Mg+2 and H2O2 increased in all regions of animals that received 3-NPA alone.

CONCLUSION

The results confirm the capacity of 3-NPA to generate oxidative stress. Besides, the study suggests that B2 or B6 vitamins restored the levels of DA and reduced oxidative stress in brain of rats. We believe that these results would help in the study of neurodegenerative diseases.

Testing a Combination of Markers of Systemic Redox Status as a Possible Tool for the Diagnosis of Late Onset Alzheimer's Disease

Background

Blood-based parameters reflecting systemic abnormalities associated with typical brain physiopathological hallmarks could be a satisfactory answer to the need of less costly/intrusive and widely available biomarkers for late onset Alzheimer's disease (LOAD). Cumulating evidence from ourselves and others suggests that systemic oxidative stress (OxS) is precociously associated with LOAD. On this basis, we aimed to identify a combination of markers of redox status that could aid the diagnosis of LOAD.

Methods

We reexamined and crossed previous data on 9 serum markers of OxS obtained in a cohort including n = 84 controls and n = 90 LOAD patients by multivariate logistic regression analyses.

Results

A multimarker panel was identified that included significantly increased (hydroperoxides and uric acid) and decreased (thiols, residual antioxidant power, and arylesterase activity) markers. The multivariate model yielded an area under receiver-operating characteristic curve (AUC) of 0.808 for the discrimination between controls and LOAD patients, with specificity and sensitivity of 64% and 79%, respectively.

Conclusions

This study identified a panel of serum markers that distinguish individuals with LOAD from cognitively healthy control subjects. Replication studies on a larger independent cohort are required to confirm and extend our data.

β-Cyclodextrin and oleic acid increase levels of dopamine and potentiates oxidative damage in young and adult rat brain

Background

Cyclodextrins are active pharmaceutical ingredients to treat neurological diseases by reducing neurotoxicity. The aim of this study was to test if combined consumption of β-cyclodextrin (BCD) and Oleic acid (OA) potentiates brain antioxidant protection.

Methods

Four groups of young Wistar rats, grouped in 6 animals each, were treated as follows: Group (G) 1, saline solution 0.9% (control); G2, BCD (0.7 g/kg); G3, OA (15 ml/kg); G4, BCD + OA. The same design was assayed for groups of adult rats. Treatments were daily administered by oral means for five consecutive days. On the last day of administration, brains of the animals were extracted to measure dopamine, 5-HIAA, glutathione (GSH), ATPase, Lipoperoxidation and H₂O_2.

Results

Oleic acid and β-cyclodextrin upgraded the levels of dopamine, 5-HIAA and lipid peroxidation and downgraded the concentrations of GSH and H₂O₂ in cortex, hemispheres (striatum) and cerebellum/medulla oblongata regions.

Conclusions

The results of the present study suggest that combined use of oleic acid and β-cyclodextrin may increase oxidative damage in brain regions and promote alteration in dopamine and 5-HIAA amines and hence, constitutes health risks among age of subjects.

Sex-dependent co-occurrence of hypoxia and β-amyloid plaques in hippocampus and entorhinal cortex is reversed by long-term treatment with ubiquinol and ascorbic acid in the 3 × Tg-AD mouse model of Alzheimer's disease

Structural and functional abnormalities in the cerebral microvasculature have been observed in Alzheimer's disease (AD) patients and animal models. One cause of hypoperfusion is the thickening of the cerebrovascular basement membrane (CVBM) due to increased collagen-IV deposition around capillaries. This study investigated whether these and other alterations in the cerebrovascular system associated with AD can be prevented by long-term dietary supplementation with the antioxidant ubiquinol (Ub) stabilized with Kaneka QH P30 powder containing ascorbic acid (ASC) in a mouse model of advanced AD (3 × Tg-AD mice, 12 months old). Animals were treated from prodromal stages of disease (3 months of age) with standard chow without or with Ub + ASC or ASC-containing vehicle and compared to wild-type (WT) mice. The number of β-amyloid (Aβ) plaques in the hippocampus and entorhinal cortex was higher in female than in male 3 × Tg-AD mice. Extensive regions of hypoxia were characterized by a higher plaque burden in females only. This was abolished by Ub + ASC and, to a lesser extent, by ASC treatment. Irrespective of Aβ burden, increased collagen-IV deposition in the CVBM was observed in both male and female 3 × Tg-AD mice relative to WT animals; this was also abrogated in Ub + ASC- and ASC-treated mice. The chronic inflammation in the hippocampus and oxidative stress in peripheral leukocytes of 3 × Tg-AD mice were likewise reversed by antioxidant treatment. These results provide strong evidence that long-term antioxidant treatment can mitigate plasma oxidative stress, amyloid burden, and hypoxia in the AD brain parenchyma.

Cholinesterase targeting by polyphenols: A therapeutic approach for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is a progressive irreversible neurodegenerative disorder characterized by excessive deposition of β-amyloid (Aβ) oligomers, and neurofibrillary tangles (NFTs), comprising of hyperphosphorylated tau proteins. The cholinergic system has been suggested as the earliest and most affected molecular mechanism that describes AD pathophysiology. Moreover, cholinesterase inhibitors (ChEIs) are the potential class of drugs that can amplify cholinergic activity to improve cognition and global performance and reduce psychiatric and behavioral disturbances. Approximately, 60%-80% of all cases of dementia in the world are patients with AD. In view of the continuous rise of this disease especially in the aged population, there is a dire need to come up with a novel compound and/or mixture that could work against this devastating disease. In this regard, the best is to rely on natural compounds rather than synthetic ones, because natural compounds are easily available, cost-effective, and comparatively less toxic. To serve this purpose, lately, scientific community has started exploring the possibility of using different polyphenols either solitary or in combination that can serve as therapeutics against AD. In the current article, we have summarized the role of various polyphenols, namely quercetin, resveratrol, curcumin, gallocatechins, cinnamic acid, caffeine, and caffeic acid as an inhibitor of cholinesterase for the treatment of AD. We have also tried to uncover the mechanistic insight on the action of these polyphenols against AD pathogenicity.

Dissecting Endoplasmic Reticulum Unfolded Protein Response (UPRER) in Managing Clandestine Modus Operandi of Alzheimer's Disease

Alzheimer's disease (AD), a neurodegenerative disorder, is most common cause of dementia witnessed among aged people. The pathophysiology of AD develops as a consequence of neurofibrillary tangle formation which consists of hyperphosphorylated microtubule associated tau protein and senile plaques of amyloid-β (Aβ) peptide in specific brain regions that result in synaptic loss and neuronal death. The feeble buffering capacity of endoplasmic reticulum (ER) proteostasis in AD is evident through alteration in unfolded protein response (UPR), where UPR markers express invariably in AD patient's brain samples. Aging weakens UPR^ER causing neuropathology and memory loss in AD. This review highlights molecular signatures of UPR^ER and its key molecular alliance that are affected in aging leading to the development of intriguing neuropathologies in AD. We present a summary of recent studies reporting usage of small molecules as inhibitors or activators of UPR^ER sensors/effectors in AD that showcase avenues for therapeutic interventions.

Exploring the nexus of Alzheimer's disease and related dementias with cancer and cancer therapies: A convening of the Alzheimer's Association & Alzheimer's Drug Discovery Foundation

Recent population studies suggest an intriguing inverse relationship between several types of cancer and neurodegenerative diseases, including Alzheimer's disease. Understanding the intersection of the underlying biology for these two distinct families of diseases with one another may offer novel approaches to identify new therapeutic approaches and possible opportunities to repurpose existing drug candidates. The Alzheimer's Association and the Alzheimer's Drug Discovery Foundation convened a one-day workshop to delve into this discussion. Workshop participants outlined research focus areas, potential collaborations, and partnerships for future action.

Neurovascular Unit Dysfunction and Blood-Brain Barrier Hyperpermeability Contribute to Schizophrenia Neurobiology: A Theoretical Integration of Clinical and Experimental Evidence

Schizophrenia is a psychotic disorder characterized by delusions, hallucinations, negative symptoms, as well as behavioral and cognitive dysfunction. It is a pathoetiologically heterogeneous disorder involving complex interrelated mechanisms that include oxidative stress and neuroinflammation. Neurovascular endothelial dysfunction and blood-brain barrier (BBB) hyperpermeability are established mechanisms in neurological disorders with comorbid psychiatric symptoms such as epilepsy, traumatic brain injury, and Alzheimer's disease. Schizophrenia is frequently comorbid with medical conditions associated with peripheral vascular endothelial dysfunction, such as metabolic syndrome, cardiovascular disease, and diabetes mellitus. However, the existence and etiological relevance of neurovascular endothelial dysfunction and BBB hyperpermeability in schizophrenia are still not well recognized. Here, we review the growing clinical and experimental evidence, indicating that neurovascular endotheliopathy and BBB hyperpermeability occur in schizophrenia patients. We present a theoretical integration of human and animal data linking oxidative stress and neuroinflammation to neurovascular endotheliopathy and BBB breakdown in schizophrenia. These abnormalities may contribute to the cognitive and behavioral symptoms of schizophrenia via several mechanisms involving reduced cerebral perfusion and impaired homeostatic processes of cerebral microenvironment. Furthermore, BBB disruption can facilitate interactions between brain innate and peripheral adaptive immunity, thereby perpetuating harmful neuroimmune signals and toxic neuroinflammatory responses, which can also contribute to the symptoms of schizophrenia. Taken together, these findings support the "mild encephalitis" hypothesis of schizophrenia. If neurovascular abnormalities prove to be etiologically relevant to the neurobiology of schizophrenia, then targeting these abnormalities may represent a promising therapeutic strategy.

Mechanisms of Mitochondrial Dysfunction in Alzheimer's Disease

Mitochondria are the primary source for energy generation in the cell, which manifests itself in the form of the adenosine triphosphate (ATP). Nicotinamide dinucleotide (NADH) molecules are the first to enter the so-called electron transport chain or ETC of the mitochondria. The ETC represents a chain of reducing agents organized into four major protein-metal complexes (I-IV) that utilize the flow of electrons to drive the production of ATP. An additional integral protein that is related to oxidative phosphorylation is ATP synthase, referred to as complex V. Complex V carries out ATP synthesis as a result of the electron flow through the ETC. The coupling of electron flow from NADH to molecular oxygen to the production of ATP represents a process known as oxidative phosphorylation. In this review, we describe mainly the bioenergetic properties of mitochondria, such as those found in the ETC that may be altered in Alzheimer's disease (AD). Increasing evidence points to several mitochondrial functions that are affected in AD. Furthermore, it is becoming apparent that mitochondria are a potential target for treatment in early-stage AD. With growing interest in the mitochondria as a target for AD, it has been hypothesized that deficit in this organelle may be at the heart of the progression of AD itself. The role of mitochondria in AD may be significant and is emerging as a main area of AD research.

Protein misfolding and aggregation in Alzheimer's disease and type 2 diabetes mellitus

In general, proteins can only execute their various biological functions when they are appropriately folded. Their amino acid sequence encodes the relevant information required for correct three-dimensional folding, with or without the assistance of chaperones. The challenge associated with understanding protein folding is currently one of the most important aspects of the biological sciences. Misfolded protein intermediates form large polymers of unwanted aggregates and are involved in the pathogenesis of many human diseases, including Alzheimer's disease (AD) and Type 2 diabetes mellitus (T2DM). AD is one of the most prevalent neurological disorders and has worldwide impact; whereas T2DM is considered a metabolic disease that detrementally influences numerous organs, afflicts some 8% of the adult population, and shares many risk factors with AD. Research data indicates that there is a widespread conformational change in the proteins involved in AD and T2DM that form β-sheet like motifs. Although conformation of these β-sheets is common to many functional proteins, the transition from α-helix to β-sheet is a typical characteristic of amyloid deposits. Any abnormality in this transition results in protein aggregation and generation of insoluble fibrils. The abnormal and toxic proteins can interact with other native proteins and consequently catalyze their transition into the toxic state. Both AD and T2DM are prevalent in the aged population. AD is characterized by the accumulation of amyloid-β (Aβ) in brain, while T2DM is characterized by the deposition of islet amyloid polypeptide (IAPP, also known as amylin) within beta-cells of the pancreas. T2DM increases pathological angiogenesis and immature vascularisation. This also leads to chronic cerebral hypoperfusion, which results in dysfunction and degeneration of neuroglial cells. With an abundance of common mechanisms underpinning both disorders, a significant question that can be posed is whether T2DM leads to AD in aged individuals and the associations between other protein misfolding diseases.

The Mechanism of Memory Enhancement of Acteoside (Verbascoside) in the Senescent Mouse Model Induced by a Combination of D-gal and AlCl3

Acteoside (verbsacoside), one of the main active phenylethanoid glycosides from Cistanche deserticola, is known to have antioxidant and neuroprotective activity, and herbs containing it are used to enhance memory. However, there is relatively little direct experimental evidence to support the use of acteoside in Alzheimer's disease (AD). The purpose of this study was to elucidate the effects of acteoside in improving learning and memory, using a mouse model of senescence induced by a combination of d-galactose and AlCl3 , and investigate its potential mechanisms compared with the positive controls vitamin E and piracetam. Acteoside was administered intragastrically at doses of 30, 60 and 120 mg/kg/day for 30 days after AD was induced. Memory function was evaluated using a step-down test. The number of neuron was analysed by haematoxylin and eosin staining and the number of Nissl bodies by Nissl staining. The expression of caspase-3 protein in hippocampus was detected by immunohistochemistry and western blot. Nitric oxide and total nitric oxide synthase level in hippocampus were also assessed. Our results showed that the latency of step down was shortened in AD model mice and the number of errors decreased after treatment with all doses of acteoside. Neurons and Nissl bodies in the hippocampus were increased significantly with higher doses (60 and 120 mg/kg/day) of acteoside. The content of nitric oxide, the activity of nitric oxide synthase and the expression of caspase-3 protein were decreased by 120 mg/kg/day acteoside compared with that of the AD model group. Our results support the results obtained previously using the Morris maze test in the same mouse model of senescence, and the use of traditional medicinal herbs containing acteoside for neuroprotection and memory loss.

Synopsis on the linkage of Alzheimer's and Parkinson's disease with chronic diseases

Neurodegeneration is the progressive loss of neuronal structure and function, which ultimately leads to neurological disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis, and Huntington's disease. Even after the recent significant advances in neurobiology, the above-mentioned disorders continue to haunt the global population. Several studies have suggested the role of specific environmental and genetic risk factors associated with these disorders. However, the exact mechanism associated with the progression of these disorders still needs to be elucidated. In the recent years, sophisticated research has revealed interesting association of prominent neurodegenerative disorders such as AD and PD with chronic diseases such as cancer, diabetes, and cardiovascular diseases. Several common molecular mechanisms such as generation of free radicals, oxidative DNA damage, aberrations in mitochondrial DNA, and dysregulation of apoptosis have been highlighted as possible points of connection. The present review summarizes the possible mechanism of coexistence of AD and PD with other chronic diseases.

Pharmacogenomics of Alzheimer's disease: novel therapeutic strategies for drug development

Alzheimer's disease (AD) is a major problem of health and disability, with a relevant economic impact on our society. Despite important advances in pathogenesis, diagnosis, and treatment, its primary causes still remain elusive, accurate biomarkers are not well characterized, and the available pharmacological treatments are not cost-effective. As a complex disorder, AD is a polygenic and multifactorial clinical entity in which hundreds of defective genes distributed across the human genome may contribute to its pathogenesis. Diverse environmental factors, cerebrovascular dysfunction, and epigenetic phenomena, together with structural and functional genomic dysfunctions, lead to amyloid deposition, neurofibrillary tangle formation, and premature neuronal death, the major neuropathological hallmarks of AD. Future perspectives for the global management of AD predict that genomics and proteomics may help in the search for reliable biomarkers. In practical terms, the therapeutic response to conventional drugs (cholinesterase inhibitors, multifactorial strategies) is genotype-specific. Genomic factors potentially involved in AD pharmacogenomics include at least five categories of gene clusters: (1) genes associated with disease pathogenesis; (2) genes associated with the mechanism of action of drugs; (3) genes associated with drug metabolism (phase I and II reactions); (4) genes associated with drug transporters; and (5) pleiotropic genes involved in multifaceted cascades and metabolic reactions. The implementation of pharmacogenomic strategies will contribute to optimize drug development and therapeutics in AD and related disorders.

Personalized Medicine of Alzheimer’s Disease

Alzheimer’s disease (AD) is a major problem of health and disability, with a relevant economic impact on society (e.g., €177 billion in Europe). Despite important advances in pathogenesis, diagnosis, and treatment, The primary causes of AD remain elusive, accurate biomarkers are not well characterized, and available pharmacological treatments are not cost-effective. As a complex disorder, AD is polygenic and multifactorial: hundreds of defective genes distributed across the human genome may contribute to its pathogenesis (with the participation of diverse environmental factors, cerebrovascular dysfunction, and epigenetic phenomena) and lead to amyloid deposition, neurofibrillary tangle formation, and premature neuronal death. Future perspectives for the global management of AD predict that structural and functional genomics and proteomics may help in the search for reliable biomarkers, and that pharmacogenomics may be an option in optimizing drug development and therapeutics.

Neurovascular unit dysfunction with blood-brain barrier hyperpermeability contributes to major depressive disorder: a review of clinical and experimental evidence

About one-third of people with major depressive disorder (MDD) fail at least two antidepressant drug trials at 1 year. Together with clinical and experimental evidence indicating that the pathophysiology of MDD is multifactorial, this observation underscores the importance of elucidating mechanisms beyond monoaminergic dysregulation that can contribute to the genesis and persistence of MDD. Oxidative stress and neuroinflammation are mechanistically linked to the presence of neurovascular dysfunction with blood-brain barrier (BBB) hyperpermeability in selected neurological disorders, such as stroke, epilepsy, multiple sclerosis, traumatic brain injury, and Alzheimer’s disease. In contrast to other major psychiatric disorders, MDD is frequently comorbid with such neurological disorders and constitutes an independent risk factor for morbidity and mortality in disorders characterized by vascular endothelial dysfunction (cardiovascular disease and diabetes mellitus). Oxidative stress and neuroinflammation are implicated in the neurobiology of MDD. More recent evidence links neurovascular dysfunction with BBB hyperpermeability to MDD without neurological comorbidity. We review this emerging literature and present a theoretical integration between these abnormalities to those involving oxidative stress and neuroinflammation in MDD. We discuss our hypothesis that alterations in endothelial nitric oxide levels and endothelial nitric oxide synthase uncoupling are central mechanistic links in this regard. Understanding the contribution of neurovascular dysfunction with BBB hyperpermeability to the pathophysiology of MDD may help to identify novel therapeutic and preventative approaches.