Pharmacogenetic considerations in the treatment of Alzheimer's disease

ADME profiling, molecular docking, DFT, and MEP analysis reveal cissamaline, cissamanine, and cissamdine from Cissampelos capensis L.f. as potential anti-Alzheimer's agents

The current pharmacotherapies for Alzheimer's disease (AD) demonstrate limited efficacy and are associated with various side effects, highlighting the need for novel therapeutic agents. Natural products, particularly from medicinal plants, have emerged as a significant source of potential neuroprotective compounds. In this context, Cissampelos capensis L.f., renowned for its medicinal properties, has recently yielded three new proaporphine alkaloids; cissamaline, cissamanine, and cissamdine. Despite their promising bioactive profiles, the biological targets of these alkaloids in the context of AD have remained unexplored. This study undertakes a comprehensive in silico examination of the binding affinity and molecular interactions of these alkaloids with human protein targets implicated in AD. The drug likeness and ADME analyses indicate favorable pharmacokinetic profiles for these compounds, suggesting their potential efficacy in targeting the central nervous system. Molecular docking studies indicate that cissamaline, cissamanine, and cissamdine interact with key AD-associated proteins. These interactions are comparable to, or in some aspects slightly less potent than, those observed with established AD drugs, highlighting their potential as novel therapeutic agents for Alzheimer's disease. Crucially, Density Functional Theory (DFT) calculations offer deep insights into the electronic and energetic characteristics of these alkaloids. These calculations reveal distinct electronic properties, with differences in total energy, binding energy, HOMO-LUMO gaps, dipole moments, and electrophilicity indices. Such variations suggest unique reactivity profiles and molecular stability, pertinent to their pharmacological potential. Moreover, Molecular Electrostatic Potential (MEP) analyses provide visual representations of the electrostatic characteristics of these alkaloids. The analyses highlight areas prone to electrophilic and nucleophilic attacks, indicating their potential for specific biochemical interactions. This combination of DFT and MEP results elucidates the intricate electronic, energetic, and electrostatic properties of these compounds, underpinning their promise as AD therapeutic agents. The in silico findings of this study shed light on the promising potential of cissamaline, cissamanine, and cissamdine as agents for AD treatment. However, further in vitro and in vivo studies are necessary to validate these theoretical predictions and to understand the precise mechanisms through which these alkaloids may exert their therapeutic effects.

Pharmacogenetics of anxiety and depression in Alzheimer's disease

Anxiety and depression coexist with cognitive impairment in Alzheimer's disease along with other concomitant disorders (>60%), which require multipurpose treatments. Polypharmaceutical regimens cause drug-drug interactions and adverse drug reactions, potentially avoidable in number and severity with the implementation of pharmacogenetic procedures. The accumulation of defective variants (>30 genes per patient in more than 50% of cases) in pharmagenes (pathogenic, mechanistic, metabolic, transporter, pleiotropic) influences the therapeutic response to antidementia, antidepressant and anxiolytic drugs in polyvalent regimens. APOE, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, CYP3A5, CYP4F2, COMT, MAOB, CHAT, GSTP1, NAT2, SLC30A8, SLCO1B1, ADRA2A, ADRB2, BCHE, GABRA1, HMGCR, HTR2C, IFNL3, NBEA, UGT1A1, ABCB1, ABCC2, ABCG2, SLC6A2, SLC6A3, SLC6A4, MTHFR and OPRM1 variants affect anxiety and depression in Alzheimer's disease.

Personalized Management and Treatment of Alzheimer's Disease

Alzheimer’s disease (AD) is a priority health problem with a high cost to society and a large consumption of medical and social resources. The management of AD patients is complex and multidisciplinary. Over 90% of patients suffer from concomitant diseases and require personalized therapeutic regimens to reduce adverse drug reactions (ADRs), drug−drug interactions (DDIs), and unnecessary costs. Men and women show substantial differences in their AD-related phenotypes. Genomic, epigenetic, neuroimaging, and biochemical biomarkers are useful for predictive and differential diagnosis. The most frequent concomitant diseases include hypertension (>25%), obesity (>70%), diabetes mellitus type 2 (>25%), hypercholesterolemia (40%), hypertriglyceridemia (20%), metabolic syndrome (20%), hepatobiliary disorder (15%), endocrine/metabolic disorders (>20%), cardiovascular disorder (40%), cerebrovascular disorder (60−90%), neuropsychiatric disorders (60−90%), and cancer (10%). Over 90% of AD patients require multifactorial treatments with risk of ADRs and DDIs. The implementation of pharmacogenetics in clinical practice can help optimize the limited therapeutic resources available to treat AD and personalize the use of anti-dementia drugs, in combination with other medications, for the treatment of concomitant disorders.

Pharmacogenetic Analyses of Therapeutic Effects of Lipophilic Statins on Cognitive and Functional Changes in Alzheimer’s Disease

Background: Pharmacogenetic effects of statins on clinical changes in Alzheimer’s disease (AD) could be mediated by epistatic interactions among relevant genetic variants involved in cholesterol metabolism. Objective: To investigate associations of HMGCR (rs3846662), NR1H2 (rs2695121), or CETP (rs5882&rs708272) with cognitive and functional changes in AD, with stratification according to APOE ɛ4 carrier status and lipid-lowering treatment with lipophilic statins. Methods: Consecutive outpatients with late-onset AD were screened with cognitive tests, while caregivers scored functionality and global ratings, with prospective neurotranslational associations documented for one year. Results: Considering n = 190:142 had hypercholesterolemia, 139 used lipophilic statins; minor allele frequencies were 0.379 (rs2695121-T:46.3% heterozygotes), 0.368 (rs5882-G:49.5% heterozygotes), and 0.371 (rs708272-A:53.2% heterozygotes), all in Hardy-Weinberg equilibrium. For APOE ɛ4 carriers: rs5882-GG protected from cognitive decline; rs5882-AA caused faster cognitive decline; carriers of rs2695121-CC or rs5882-AA were more susceptible to harmful cognitive effects of lipophilic statins; carriers of rs5882-GG or rs708272-AG had functional benefits when using lipophilic statins. APOE ɛ4 non-carriers resisted any cognitive or functional effects of lipophilic statins, while invariability of rs3846662 (all AA) prevented the assessment of HMGCR effects. When assessing CETP haplotypes only: rs5882-GG protected from cognitive and functional decline, regardless of lipophilic statin therapy; lipophilic statins usually caused cognitive and functional harm to carriers of rs5882-A and/or rs708272-A; lipophilic statins benefitted cognition and functionality of carriers of rs5882-G and/or rs708272-G. Conclusion: Reportedly protective variants of CETP and NR1H2 also slowed cognitive and functional decline particularly for APOE ɛ4 carriers, and regardless of cholesterol variations, while therapy with lipophilic statins might affect carriers of specific genetic variants.

Epigenetic Studies in the Male APP/BIN1/COPS5 Triple-Transgenic Mouse Model of Alzheimer's Disease

Alzheimer's Disease (AD) is a major health problem worldwide. The lack of efficacy of existing therapies for AD is because of diagnosis at late stages of the disease, limited knowledge of biomarkers, and molecular mechanisms of AD pathology, as well as conventional drugs that are focused on symptomatic rather than mechanistic features of the disease. The connection between epigenetics and AD, however, may be useful for the development of novel therapeutics or diagnostic biomarkers for AD. The aim of this study was to investigate a pathogenic role for epigenetics and other biomarkers in the male APP/BIN1/COPS5 triple-transgenic (3xTg) mouse model of AD. In the APP/BIN1/COPS5 3xTg-AD mouse hippocampus, sirtuin expression and activity decreased, HDAC3 expression and activity increased, PSEN1 mRNA levels were unchanged, PSEN2 and APOE expression was reduced, and levels of the pro-inflammatory marker IL-6 increased; levels of pro-inflammatory COX-2 and TNFα and apoptotic (NOS3) markers increased slightly, but these were non-significant. In fixed mouse-brain slices, immunoreactivity for CD11b and β-amyloid immunostaining increased. APP/BIN1/COPS5 3xTg-AD mice are a suitable model for evaluating epigenetic changes in AD, the discovery of new epigenetic-related biomarkers for AD diagnosis, and new epidrugs for the treatment of this neurodegenerative disease.

Pharmacogenomics of Alzheimer's Disease: Novel Strategies for Drug Utilization and Development

Alzheimer's disease (AD) is a priority health problem in developed countries with a high cost to society. Approximately 20% of direct costs are associated with pharmacological treatment. Over 90% of patients require multifactorial treatments, with risk of adverse drug reactions (ADRs) and drug-drug interactions (DDIs) for the treatment of concomitant diseases such as hypertension (>25%), obesity (>70%), diabetes mellitus type 2 (>25%), hypercholesterolemia (40%), hypertriglyceridemia (20%), metabolic syndrome (20%), hepatobiliary disorder (15%), endocrine/metabolic disorders (>20%), cardiovascular disorder (40%), cerebrovascular disorder (60-90%), neuropsychiatric disorders (60-90%), and cancer (10%).For the past decades, pharmacological studies in search of potential treatments for AD focused on the following categories: neurotransmitter enhancers (11.38%), multitarget drugs (2.45%), anti-amyloid agents (13.30%), anti-tau agents (2.03%), natural products and derivatives (25.58%), novel synthetic drugs (8.13%), novel targets (5.66%), repository drugs (11.77%), anti-inflammatory drugs (1.20%), neuroprotective peptides (1.25%), stem cell therapy (1.85%), nanocarriers/nanotherapeutics (1.52%), and other compounds (<1%).Pharmacogenetic studies have shown that the therapeutic response to drugs in AD is genotype-specific in close association with the gene clusters that constitute the pharmacogenetic machinery (pathogenic, mechanistic, metabolic, transporter, pleiotropic genes) under the regulatory control of epigenetic mechanisms (DNA methylation, histone/chromatin remodeling, microRNA regulation). Most AD patients (>60%) are carriers of over ten pathogenic genes. The genes that most frequently (>50%) accumulate pathogenic variants in the same AD case are A2M (54.38%), ACE (78.94%), BIN1 (57.89%), CLU (63.15%), CPZ (63.15%), LHFPL6 (52.63%), MS4A4E (50.87%), MS4A6A (63.15%), PICALM (54.38%), PRNP (80.7059), and PSEN1 (77.19%). There is also an accumulation of 15 to 26 defective pharmagenes in approximately 85% of AD patients. About 50% of AD patients are carriers of at least 20 mutant pharmagenes, and over 80% are deficient metabolizers for the most common drugs, which are metabolized via the CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 enzymes.The implementation of pharmacogenetics can help optimize drug development and the limited therapeutic resources available to treat AD, and personalize the use of anti-dementia drugs in combination with other medications for the treatment of concomitant disorders.

Genophenotypic Factors and Pharmacogenomics in Adverse Drug Reactions

Adverse drug reactions (ADRs) rank as one of the top 10 leading causes of death and illness in developed countries. ADRs show differential features depending upon genotype, age, sex, race, pathology, drug category, route of administration, and drug–drug interactions. Pharmacogenomics (PGx) provides the physician effective clues for optimizing drug efficacy and safety in major problems of health such as cardiovascular disease and associated disorders, cancer and brain disorders. Important aspects to be considered are also the impact of immunopharmacogenomics in cutaneous ADRs as well as the influence of genomic factors associated with COVID-19 and vaccination strategies. Major limitations for the routine use of PGx procedures for ADRs prevention are the lack of education and training in physicians and pharmacists, poor characterization of drug-related PGx, unspecific biomarkers of drug efficacy and toxicity, cost-effectiveness, administrative problems in health organizations, and insufficient regulation for the generalized use of PGx in the clinical setting. The implementation of PGx requires: (i) education of physicians and all other parties involved in the use and benefits of PGx; (ii) prospective studies to demonstrate the benefits of PGx genotyping; (iii) standardization of PGx procedures and development of clinical guidelines; (iv) NGS and microarrays to cover genes with high PGx potential; and (v) new regulations for PGx-related drug development and PGx drug labelling.

Influence of Pathogenic and Metabolic Genes on the Pharmacogenetics of Mood Disorders in Alzheimer's Disease

Background: Mood disorders represent a risk factor for dementia and are present in over 60% of cases with Alzheimer’s disease (AD). More than 80% variability in drug pharmacokinetics and pharmacodynamics is associated with pharmacogenetics. Methods: Anxiety and depression symptoms were assessed in 1006 patients with dementia (591 females, 415 males) and the influence of pathogenic (APOE) and metabolic (CYP2D6, CYP2C19, and CYP2C9) gene variants on the therapeutic outcome were analyzed after treatment with a multifactorial regime in a natural setting. Results and Conclusions: (i) Biochemical, hematological, and metabolic differences may contribute to changes in drug efficacy and safety; (ii) anxiety and depression are more frequent and severe in females than males; (iii) both females and males respond similarly to treatment, showing significant improvements in anxiety and depression; (iv) APOE-3 carriers are the best responders and APOE-4 carriers tend to be the worst responders to conventional treatments; and (v) among CYP2D6, CYP2C19, and CYP2C9 genophenotypes, normal metabolizers (NMs) and intermediate metabolizers (IMs) are significantly better responders than poor metabolizers (PMs) and ultra-rapid metabolizers (UMs) to therapeutic interventions that modify anxiety and depression phenotypes in dementia. APOE-4 carriers and CYP-related PMs and UMs deserve special attention for their vulnerability and poor response to current treatments.

ACAT1 as a Therapeutic Target and its Genetic Relationship with Alzheimer's Disease

BACKGROUND

Alzheimer´s disease (AD) is a chronic and progressive disease which impacts caregivers, families and societies physically, psychologically and economically. Currently available drugs can only improve cognitive symptoms, have no impact on progression and are not curative, so identifying and studying new drug targets is important. There are evidences which indicate disturbances in cholesterol homeostasis can be related with AD pathology, especially the compartmentation of intracellular cholesterol and cytoplasmic cholesterol esters formed by acyl-CoA: cholesterol acyltransferase 1 (ACAT1) can be implicated in the regulation of amyloid-beta (Aβ) peptide, involved in AD. Blocking ACAT1 activity, beneficial effects are obtained, so it has been suggested that ACAT1 can be a potential new therapeutic target. The present review discusses the role of cholesterol homeostasis in AD pathology, especially with ACAT inhibitors, and how they have been raised as a therapeutic approach. In addition, the genetic relationship of ACAT and AD is discussed.

CONCLUSION

Although there are several lines of evidence from cell-based and animal studies that suggest that ACAT inhibition is an effective way of reducing cerebral Aβ, there is still an information gap in terms of mechanisms and concerns to cover before passing to the next level. Additionally, an area of interest that may be useful in understanding AD to subsequently propose new therapeutic approaches is pharmacogenetics; however, there is still a lot of missing information in this area.

Synaptic Pruning in Alzheimer's Disease: Role of the Complement System

Alz heimer’s disease (AD) continues to threaten aged individuals and health care systems around the world. Human beings have been trying to postpone, reduce, or eliminate the primary risk factor for AD, aging, throughout history. Despite this, there is currently only symptomatic treatment for AD and this treatment is limited to only a handful of FDA approved AD drugs.

Gene Polymorphisms Affecting the Pharmacokinetics and Pharmacodynamics of Donepezil Efficacy

Donepezil (DNP) is the first-line drug used for Alzheimer's disease (AD). However, the therapeutic response rate of patients to DNP varies from 20 to 60%. The main reason for the large differences in the clinical efficacy of DNP therapy is genetic factors, some of which affect pharmacokinetics (PK), while others affect pharmacodynamics (PD). Thus, much emphasis has been placed on the investigation of an association between PK- and PD-related gene polymorphisms and therapeutic response to DNP, but a consistent view does not yet exist. In this review, we summarize recent findings regarding genetic factors influencing the clinical efficacy of DNP, including substantial differences in individual responses as a consequence of polymorphisms in Cytochrome P450 (CYP) 2D6, CY3A4, CY3A5, APOE, ABCA1, ABCB1, ESR1, BCHE, PON-1, CHRNA7, and CHAT. We also discuss possible strategies for the evaluation of the clinical efficacy of DNP, with a specific focus on possible biomarkers of PK/PD parameters, and provide perspectives and limitations within the field, which will also be beneficial for understanding the multiple mechanisms of DNP therapy in AD.

Selected LDLR and APOE Polymorphisms Affect Cognitive and Functional Response to Lipophilic Statins in Alzheimer's Disease

Effects of statins over clinical changes in Alzheimer's disease (AD) are usually non-significant, but epistatic interactions between genetic variants involved in cholesterol metabolism could be important for such effects. We aimed to investigate whether LDLR single-nucleotide polymorphisms rs11669576 (LDLR8), rs5930 (LDLR10), and rs5925 (LDLR13) are associated with cognitive and functional changes in AD, while also considering APOE haplotypes and lipid-lowering treatment with lipophilic statins for stratification. Consecutive outpatients with late-onset AD were screened with cognitive tests, while caregivers scored functionality and caregiver burden, with prospective neurotranslational correlations documented for 1 year. For 179 patients, minor allele frequencies were 0.078 for rs11669576-A (14.5% heterozygotes), 0.346 for rs5930-A (42.5% heterozygotes), and 0.444 for rs5925-C (56.4% heterozygotes), all in Hardy-Weinberg equilibrium; 134 patients had hypercholesterolemia, and 133 used lipophilic statins. Carriers of rs11669576-G had faster cognitive decline, while functional decline was slower for carriers of rs11669576-A who used lipophilic statins. APOE-ε4 carriers who also carried rs5930-AA had improved caregiver burden, while carriers of haplotypes that included rs5930-AG had worse cognitive and functional outcomes, though carriers of the A allele of rs5930 had better cognitive and functional response to lipophilic statins. APOE-ε4 non-carriers who carried rs5925-TT had slower cognitive decline, while lipophilic statins protected carriers of the other genotypes. We preliminarily conclude that reportedly protective variants of LDLR and APOE against risk of AD also slowed cognitive decline, regardless of cholesterol variations, while therapy with lipophilic statins might benefit carriers of specific genetic variants.

Simple analogues of natural product chelerythrine: Discovery of a novel anticholinesterase 2-phenylisoquinolin-2-ium scaffold with excellent potency against acetylcholinesterase

As simple analogues of the natural compound chelerythrine, a novel anti-cholinesterase 2-phenylisoquinolin-2-ium scaffold was designed by structure imitation. The activity evaluation led to the discovery of seven compounds with potent anti-acetylcholinesterase activity with IC₅₀ values of ≤0.72 μM, superior to chelerythrine and standard drugs galantamine. Particularly, compound 8y showed the excellent dual acetylcholinesterase-butyrylcholinesterase inhibition activity, superior to rivastigmine, a dual cholinesterase inhibitor drug. Furthermore, the compounds displayed a competitive anti-acetylcholinesterase mechanism with the substrate and low cytotoxicity. Molecular docking showed that the isoquinoline moiety is embedded in a cavity surrounded by four aromatic residues of acetylcholinesterase by the π-π action. Structure-activity relationship showed that the p-substituents on the C-ring can dramatically improve the anti-acetylcholinesterase activity, while 8-OMe can increase the activity against the two cholinesterases simultaneously. Thus, the title compounds emerged as promising lead compounds for the development of novel cholinesterase inhibitor agents.

Pharmacogenomics of Cognitive Dysfunction and Neuropsychiatric Disorders in Dementia

Symptomatic interventions for patients with dementia involve anti-dementia drugs to improve cognition, psychotropic drugs for the treatment of behavioral disorders (BDs), and different categories of drugs for concomitant disorders. Demented patients may take >6–10 drugs/day with the consequent risk for drug–drug interactions and adverse drug reactions (ADRs >80%) which accelerate cognitive decline. The pharmacoepigenetic machinery is integrated by pathogenic, mechanistic, metabolic, transporter, and pleiotropic genes redundantly and promiscuously regulated by epigenetic mechanisms. CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 geno-phenotypes are involved in the metabolism of over 90% of drugs currently used in patients with dementia, and only 20% of the population is an extensive metabolizer for this tetragenic cluster. ADRs associated with anti-dementia drugs, antipsychotics, antidepressants, anxiolytics, hypnotics, sedatives, and antiepileptic drugs can be minimized by means of pharmacogenetic screening prior to treatment. These drugs are substrates, inhibitors, or inducers of 58, 37, and 42 enzyme/protein gene products, respectively, and are transported by 40 different protein transporters. APOE is the reference gene in most pharmacogenetic studies. APOE-3 carriers are the best responders and APOE-4 carriers are the worst responders; likewise, CYP2D6-normal metabolizers are the best responders and CYP2D6-poor metabolizers are the worst responders. The incorporation of pharmacogenomic strategies for a personalized treatment in dementia is an effective option to optimize limited therapeutic resources and to reduce unwanted side-effects.

Pharmacogenetics in the clinical analysis laboratory: clinical practice, research, and drug development pipeline

Introduction: Over the last decade, the spread of next-generation sequencing technology along with the rising cost in health management in national health systems has led to widespread use/abuse of pharmacogenetic tests (PGx) in the practice of many clinical disciplines. However, given their clinical significance, it is important to standardize these tests for having an interaction with the clinical analysis laboratory (CAL), in which a PGx service can meet these requirements. Areas covered: A diagnostic test must meet the criteria of reproducibility and validity for its utility in the clinical routine. This present review mainly describes the utility of introducing PGx tests in the CAL routine to produce correct results useful for setting up personalized drug treatments. Expert opinion: With a PGx service, CALs can provide the right tool to help clinicians to make better choices about different categories of drugs and their dosage and to manage the economic impact both in hospital-based settings and in National Health Services, throughout electronic health records. Advances in PGx also allow a new approach for pharmaceutical companies in order to improve drug development and clinical trials. As a result, CALs can achieve a powerful source of epidemiological, clinical, and research findings from PGx tests.

Peptides as epigenetic modulators: therapeutic implications

Peptides originating from different sources (endogenous, food derived, environmental, and synthetic) are able to influence different aspects of epigenetic regulation. Endogenous short peptides, resulting from proteolytic cleavage of proteins or upon translation of non-annotated out of frame transcripts, can block DNA methylation and hereby regulate gene expression. Peptides entering the body by digestion of food-related proteins can modulate DNA methylation and/or histone acetylation while environmental peptides, synthesized by bacteria, fungi, and marine sponges, mainly inhibit histone deacetylation. In addition, synthetic peptides that reverse or inhibit different epigenetic modifications of both histones and the DNA can be developed as well. Next to these DNA and histone modifications, peptides can also influence the expression of non-coding RNAs such as lncRNAs and the maturation of miRNAs.

Seen the advantages over small molecules, the development of peptide therapeutics is an interesting approach to treat diseases with a strong epigenetic basis like cancer and Alzheimer’s disease. To date, only a limited number of drugs with a proven epigenetic mechanism of action have been approved by the FDA of which two (romidepsin and nesiritide) are peptides. A large knowledge gap concerning epigenetic effects of peptides is present, and this class of molecules deserves more attention in the development as epigenetic modulators. In addition, none of the currently approved peptide drugs are under investigation for their potential effects on epigenetics, hampering drug repositioning of these peptides to other indications with an epigenetic etiology.

Sirtuins in Alzheimer's Disease: SIRT2-Related GenoPhenotypes and Implications for PharmacoEpiGenetics

Sirtuins (SIRT1-7) are NAD⁺-dependent protein deacetylases/ADP ribosyltransferases with important roles in chromatin silencing, cell cycle regulation, cellular differentiation, cellular stress response, metabolism and aging. Sirtuins are components of the epigenetic machinery, which is disturbed in Alzheimer’s disease (AD), contributing to AD pathogenesis. There is an association between the SIRT2-C/T genotype (rs10410544) (50.92%) and AD susceptibility in the APOEε4-negative population (SIRT2-C/C, 34.72%; SIRT2-T/T 14.36%). The integration of SIRT2 and APOE variants in bigenic clusters yields 18 haplotypes. The 5 most frequent bigenic genotypes in AD are 33CT (27.81%), 33CC (21.36%), 34CT (15.29%), 34CC (9.76%) and 33TT (7.18%). There is an accumulation of APOE-3/4 and APOE-4/4 carriers in SIRT2-T/T > SIRT2-C/T > SIRT2-C/C carriers, and also of SIRT2-T/T and SIRT2-C/T carriers in patients who harbor the APOE-4/4 genotype. SIRT2 variants influence biochemical, hematological, metabolic and cardiovascular phenotypes, and modestly affect the pharmacoepigenetic outcome in AD. SIRT2-C/T carriers are the best responders, SIRT2-T/T carriers show an intermediate pattern, and SIRT2-C/C carriers are the worst responders to a multifactorial treatment. In APOE-SIRT2 bigenic clusters, 33CC carriers respond better than 33TT and 34CT carriers, whereas 24CC and 44CC carriers behave as the worst responders. CYP2D6 extensive metabolizers (EM) are the best responders, poor metabolizers (PM) are the worst responders, and ultra-rapid metabolizers (UM) tend to be better responders that intermediate metabolizers (IM). In association with CYP2D6 genophenotypes, SIRT2-C/T-EMs are the best responders. Some Sirtuin modulators might be potential candidates for AD treatment.

Pharmacoepigenomic Interventions as Novel Potential Treatments for Alzheimer's and Parkinson's Diseases

Cerebrovascular and neurodegenerative disorders affect one billion people around the world and result from a combination of genomic, epigenomic, metabolic, and environmental factors. Diagnosis at late stages of disease progression, limited knowledge of gene biomarkers and molecular mechanisms of the pathology, and conventional compounds based on symptomatic rather than mechanistic features, determine the lack of success of current treatments, including current FDA-approved conventional drugs. The epigenetic approach opens new avenues for the detection of early presymptomatic pathological events that would allow the implementation of novel strategies in order to stop or delay the pathological process. The reversibility and potential restoring of epigenetic aberrations along with their potential use as targets for pharmacological and dietary interventions sited the use of epidrugs as potential novel candidates for successful treatments of multifactorial disorders involving neurodegeneration. This manuscript includes a description of the most relevant epigenetic mechanisms involved in the most prevalent neurodegenerative disorders worldwide, as well as the main potential epigenetic-based compounds under investigation for treatment of those disorders and their limitations.

Pleiotropy and promiscuity in pharmacogenomics for the treatment of Alzheimer's disease and related risk factors

Patients with Alzheimer's disease are current consumers of polypharmacy with a high risk for drug–drug interactions. Antidementia drugs and other pharmacological treatments for vascular risk factors associated with dementia exert pleiotropic effects which are promiscuously regulated by different gene products. The aim of this review is to highlight the influence of genes involved in pharmacogenetics (i.e., pathogenic, mechanistic, metabolic, transporter and pleiotropic genes) as major determinants of response to treatment in Alzheimer's disease. Patients harboring poor or ultrarapid geno-phenotypes display more irregular profiles in drug efficacy and safety than extensive or intermediate metabolizers. Polymorphic variants of genes associated with lipid metabolism influence the therapeutic response to hypolipemic agents. Understanding these effects is very useful for optimizing polytherapy in dementia.

Have there been improvements in Alzheimer's disease drug discovery over the past 5 years?

INTRODUCTION

Alzheimer's disease (AD) is the most important neurodegenerative disorder with a global cost worldwide of over $700 billion. Pharmacological treatment accounts for 10-20% of direct costs; no new drugs have been approved during the past 15 years; and the available medications are not cost-effective. Areas covered: A massive scrutiny of AD-related PubMed publications (ps)(2013-2017) identified 42,053ps of which 8,380 (19.60%) were associated with AD treatments. The most prevalent pharmacological categories included neurotransmitter enhancers (11.38%), multi-target drugs (2.45%), anti-Amyloid agents (13.30%), anti-Tau agents (2.03%), natural products and derivatives (25.58%), novel drugs (8.13%), novel targets (5.66%), other (old) drugs (11.77%), anti-inflammatory drugs (1.20%), neuroprotective peptides (1.25%), stem cell therapy (1.85%), nanocarriers/nanotherapeutics (1.52%), and others (<1% each). Expert opinion: Unsuccessful outcomes in AD therapeutics are attributed to pathogenic misconceptions, erratic procedures in drug development and inappropriate regulations. Recommendations for the future are as follows: (i) the reconsideration of dominant pathogenic theories, (ii) the identification of reliable biomarkers, (iii) the redefinition of diagnostic criteria, (iv) new guidelines for disease management, (v) the reorientation of drug discovery programs, (vi) the updating of regulatory requirements, (vii) the introduction of pharmacogenomics in drug development and personalized treatments, and (viii) the implementation of preventive programs.

New 2-Aryl-9-methyl-β-carbolinium salts as Potential Acetylcholinesterase Inhibitor agents: Synthesis, Bioactivity and Structure-Activity Relationship

A series of 2-aryl-9-methyl-β-carbolinium bromides (B) were synthesized and explored for anti-acetylcholinesterase (AChE) activities in vitro, action mechanism and structure-activity relationship. All the compounds B along with their respective 3,4-dihydro intermediates (A) presented anti-AChE activity at 10 μM. Thirteen compounds B showed the excellent activity with IC₅₀ values of 0.11–0.76 μM and high selectivity toward AChE relative to butyrylcholinesterase (BChE), superior to galantamine (IC₅₀ = 0.79 μM), a selective AChE inhibitor drug. Kinetic analysis showed that the action mechanisms of both compounds B and A are a competitive inhibition model. Structure-activity relationship analyses showed that the C = N⁺ moiety is a determinant for the activity. Substituents at 6, 7 or 4′ site, the indole-N-alkyl and the aromatization of the C-ring can significantly improve the activity. Molecular docking studies showed that the compounds could combine with the active site of AChE by the π-π or cation-π action between the carboline ring and the phenyl rings of the residues, and the β-carboline moiety is embedded in a cavity surrounded by four aromatic residues of Trp86, Tyr337, Trp439 and Tyr449. The present results strongly suggest that the para-position of the D-ring should be a preferred modification site for further structural optimization design. Thus, 2-aryl-9-methyl-β-carboliniums emerged as novel and promising tool compounds for the development of new AChE inhibitor agents.

Pharmacogenetics of Vascular Risk Factors in Alzheimer's Disease

Alzheimer’s disease (AD) is a polygenic/complex disorder in which genomic, epigenomic, cerebrovascular, metabolic, and environmental factors converge to define a progressive neurodegenerative phenotype. Pharmacogenetics is a major determinant of therapeutic outcome in AD. Different categories of genes are potentially involved in the pharmacogenetic network responsible for drug efficacy and safety, including pathogenic, mechanistic, metabolic, transporter, and pleiotropic genes. However, most drugs exert pleiotropic effects that are promiscuously regulated for different gene products. Only 20% of the Caucasian population are extensive metabolizers for tetragenic haplotypes integrating CYP2D6-CYP2C19-CYP2C9-CYP3A4/5 variants. Patients harboring CYP-related poor (PM) and/or ultra-rapid (UM) geno-phenotypes display more irregular profiles in drug metabolism than extensive (EM) or intermediate (IM) metabolizers. Among 111 pentagenic (APOE-APOB-APOC3-CETP-LPL) haplotypes associated with lipid metabolism, carriers of the H26 haplotype (23-TT-CG-AG-CC) exhibit the lowest cholesterol levels, and patients with the H104 haplotype (44-CC-CC-AA-CC) are severely hypercholesterolemic. Furthermore, APOE, NOS3, ACE, AGT, and CYP variants influence the therapeutic response to hypotensive drugs in AD patients with hypertension. Consequently, the implementation of pharmacogenetic procedures may optimize therapeutics in AD patients under polypharmacy regimes for the treatment of concomitant vascular disorders.

Parkinson's Disease: From Pathogenesis to Pharmacogenomics

Parkinson's disease (PD) is the second most important age-related neurodegenerative disorder in developed societies, after Alzheimer's disease, with a prevalence ranging from 41 per 100,000 in the fourth decade of life to over 1900 per 100,000 in people over 80 years of age. As a movement disorder, the PD phenotype is characterized by rigidity, resting tremor, and bradykinesia. Parkinson's disease -related neurodegeneration is likely to occur several decades before the onset of the motor symptoms. Potential risk factors include environmental toxins, drugs, pesticides, brain microtrauma, focal cerebrovascular damage, and genomic defects. Parkinson's disease neuropathology is characterized by a selective loss of dopaminergic neurons in the substantia nigra pars compacta, with widespread involvement of other central nervous system (CNS) structures and peripheral tissues. Pathogenic mechanisms associated with genomic, epigenetic and environmental factors lead to conformational changes and deposits of key proteins due to abnormalities in the ubiquitin-proteasome system together with dysregulation of mitochondrial function and oxidative stress. Conventional pharmacological treatments for PD are dopamine precursors (levodopa, l-DOPA, l-3,4 dihidroxifenilalanina), and other symptomatic treatments including dopamine agonists (amantadine, apomorphine, bromocriptine, cabergoline, lisuride, pergolide, pramipexole, ropinirole, rotigotine), monoamine oxidase (MAO) inhibitors (selegiline, rasagiline), and catechol-O-methyltransferase (COMT) inhibitors (entacapone, tolcapone). The chronic administration of antiparkinsonian drugs currently induces the "wearing-off phenomenon", with additional psychomotor and autonomic complications. In order to minimize these clinical complications, novel compounds have been developed. Novel drugs and bioproducts for the treatment of PD should address dopaminergic neuroprotection to reduce premature neurodegeneration in addition to enhancing dopaminergic neurotransmission. Since biochemical changes and therapeutic outcomes are highly dependent upon the genomic profiles of PD patients, personalized treatments should rely on pharmacogenetic procedures to optimize therapeutics.