Concordant peripheral lipidome signatures in two large clinical studies of Alzheimer's disease

Structural Characterization and Quantitation of Ether-Linked Glycerophospholipids in Peroxisome Biogenesis Disorder Tissue by Ultraviolet Photodissociation Mass Spectrometry

The biological impact of ether glycerophospholipids (GP) in peroxisomal disorders and other diseases makes them significant targets as biomarkers for diagnostic assays or deciphering pathology of the disorders. Ether lipids include both plasmanyl and plasmenyl lipids, which each contain an ether or a vinyl ether bond at the sn-1 linkage position, respectively. This linkage, in contrast to traditional diacyl GPs, precludes their detailed characterization by mass spectrometry via traditional collisional-based MS/MS techniques. Additionally, the isomeric nature of plasmanyl and plasmenyl pairs of ether lipids introduces a further level of complexity that impedes analysis of these species. Here, we utilize 213 nm ultraviolet photodissociation mass spectrometry (UVPD-MS) for detailed characterization of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) plasmenyl and plasmanyl lipids in mouse brain tissue. 213 nm UVPD-MS enables the successful differentiation of these four ether lipid subtypes for the first time. We couple this UVPD-MS methodology to reversed-phase liquid chromatography (RPLC) for characterization and relative quantitation of ether lipids from normal and diseased (Pex7 deficiency modeling the peroxisome biogenesis disorder, RCDP) mouse brain tissue, highlighting the ability to pinpoint specific structural features of ether lipids that are important for monitoring aberrant lipid metabolism in peroxisomal disorders.

Ecological lipidology

Dietary lipids (DLs), particularly sterols and fatty acids, are precursors for endogenous lipids that, unusually for macronutrients, shape cellular and organismal function long after ingestion. These functions – cell membrane structure, intracellular signalling, and hormonal activity – vary with the identity of DLs, and scale up to influence health, survival, and reproductive fitness, thereby affecting evolutionary change. Our Ecological Lipidology approach integrates biochemical mechanisms and molecular cell biology into evolution and nutritional ecology. It exposes our need to understand environmental impacts on lipidomes, the lipid specificity of cell functions, and predicts the evolution of lipid-based diet choices. Broad interdisciplinary implications of Ecological Lipidology include food web alterations, species responses to environmental change, as well as sex differences and lifestyle impacts on human nutrition, and opportunities for DL-based therapies.

Regulation of plasmalogen metabolism and traffic in mammals: The fog begins to lift

Due to their unique chemical structure, plasmalogens do not only exhibit distinct biophysical and biochemical features, but require specialized pathways of biosynthesis and metabolization. Recently, major advances have been made in our understanding of these processes, for example by the attribution of the gene encoding the enzyme, which catalyzes the final desaturation step in plasmalogen biosynthesis, or by the identification of cytochrome C as plasmalogenase, which allows for the degradation of plasmalogens. Also, models have been presented that plausibly explain the maintenance of adequate cellular levels of plasmalogens. However, despite the progress, many aspects around the questions of how plasmalogen metabolism is regulated and how plasmalogens are distributed among organs and tissues in more complex organisms like mammals, remain unresolved. Here, we summarize and interpret current evidence on the regulation of the enzymes involved in plasmalogen biosynthesis and degradation as well as the turnover of plasmalogens. Finally, we focus on plasmalogen traffic across the mammalian body - a topic of major importance, when considering plasmalogen replacement therapies in human disorders, where deficiencies in these lipids have been reported. These involve not only inborn errors in plasmalogen metabolism, but also more common diseases including Alzheimer's disease and neurodevelopmental disorders.

[Blood Based Biomarker for Optimization of Early and Differential Diagnosis of Alzheimer's Dementia]

AIM

Dementia in Alzheimer´s disease is a global challenge. There is growing evidence that investigating blood biomarkers to diagnose Alzheimer´s disease is a promising fast, minimally invasive, and less costly method. The aim of this study was to review available studies on promising biomarkers for Alzheimer´s disease.

METHOD

The latest studies were collated for this review.

RESULTS

Immunoassays followed by mass spectrometry and immunomagnetic reduction were reported to be highly relevant methods for detecting amyloid-ß 42 (Aß42) and amyloid-ß 40 (Aß40) to calculate the Aß42/Aß40 ratio, thereby improving the early diagnosis of Alzheimer´s disease. Amyloid-ß (Aß) peptides in blood plasma were considered as potential markers, as they correlated with the brain's Aß pathology. Phosphorylated tau protein 181 (p-tau181), phosphorylated tau protein 217 (p-tau217) and phosphorylated tau protein 231 (p-tau231) in blood samples assessed via Simoa technology served as parameters for the early and differential diagnosis of AD, and were markers of tau pathology in the brain. Neurofilament light chain (Nfl) and glial fibrillary acid protein (GFAP) were additional markers possibly facilitating the assessment of axonal and astroglial brain damage in Alzheimer´s disease. GFAP in blood was useful as an additional marker to detect early and to predict the time course of Alzheimer´s disease.

CONCLUSIONS

Determining blood biomarkers represents less invasive and less costly diagnostics for Alzheimer´s disease. The investigation of blood biomarkers such as the Aß42/Aß40 ratio, p-tau217, p-tau231, Nfl and GFAP have been promising in establishing the AT(N) classification for Alzheimer´s disease. High-throughput methods should be evaluated in large patient cohort studies and via meta-analyses of studies. Consensus criteria with standard protocols for measuring these biomarkers while considering ethical issues and Alzheimer´s phenotype should unify normative values from different laboratories. The AT(N) classification of Alzheimer´s disease in blood would be a key element towards the implementation of minimally-invasive precision medicine.

Early Serum Metabolism Profile of Post-operative Delirium in Elderly Patients Following Cardiac Surgery With Cardiopulmonary Bypass

Background

Cardiac surgery with cardiopulmonary bypass (CPB) is considered to be one of the surgical types with the highest incidence of post-operative delirium (POD). POD has been associated with a prolonged intensive care and hospital stay, long-term neurocognitive deterioration, and increased mortality. However, the specific pathogenesis of POD is still unclear. Untargeted metabolomics techniques can be used to understand the changes of serum metabolites in early POD to discover the relationship between serum metabolites and disease.

Materials and Methods

The present study recruited 58 elderly patients undergoing cardiac surgery with CPB. Serum was collected within the first 24 h after surgery. The Confusion Assessment Method (CAM) and ICU-CAM assessments were used to identify patients who experienced POD. All patients with normal post-operative cognitive assessment were included in the non-POD groups. Moreover, we collected serum from 20 healthy adult volunteers. We performed untargeted analyses of post-operative serum metabolites in all surgical groups, as well as serum metabolites in healthy non-surgical adults by using liquid chromatography mass spectrometry (LC/MS) and analyzed metabolic profiles and related metabolites.

Results

The probability of POD after cardiac surgery were 31%. There were statistically significant differences in post-operative mechanical ventilation time, ICU stay time and post-operative hospital stay between POD and non-POD group (P < 0.05). And ICU stay time was an independent risk factor for POD. The analysis revealed that a total of 51 differentially expressed metabolites (DEMs) were identified by comparing the POD and non-POD group, mostly lipids and lipid-like molecules. Three phosphatidylinositol (PI) were down-regulated in POD group, i.e., PI [18:0/18:2 (9Z, 12Z)], PI [20:4 (8Z, 11Z, 14Z, 17Z)/18:0], and PI [18:1 (9Z)/20:3 (8Z, 11Z, 14Z)]. The receiver operating characteristic (ROC) curve analysis showed that three kinds of PI metabolites had the highest area under the curve (AUC), which were 0.789, 0.781, and 0.715, respectively. Correlation analysis showed that the expression of three PIs was negatively correlated with the incidence of POD.

Conclusion

Our findings suggest that lipid metabolism plays an important role in the serum metabolic profile of elderly patients with POD in the early post-operative period. Low serum lipid metabolic PI was associated with incidence of POD in elderly following cardiac bypass surgery, which may provide new insights into the pathogenesis of POD.

Comprehensive genetic analysis of the human lipidome identifies loci associated with lipid homeostasis with links to coronary artery disease

We integrated lipidomics and genomics to unravel the genetic architecture of lipid metabolism and identify genetic variants associated with lipid species putatively in the mechanistic pathway for coronary artery disease (CAD). We quantified 596 lipid species in serum from 4,492 individuals from the Busselton Health Study. The discovery GWAS identified 3,361 independent lipid-loci associations, involving 667 genomic regions (479 previously unreported), with validation in two independent cohorts. A meta-analysis revealed an additional 70 independent genomic regions associated with lipid species. We identified 134 lipid endophenotypes for CAD associated with 186 genomic loci. Associations between independent lipid-loci with coronary atherosclerosis were assessed in ∼456,000 individuals from the UK Biobank. Of the 53 lipid-loci that showed evidence of association (P < 1 × 10-3), 43 loci were associated with at least one lipid endophenotype. These findings illustrate the value of integrative biology to investigate the aetiology of atherosclerosis and CAD, with implications for other complex diseases.

Early life infection and proinflammatory, atherogenic metabolomic and lipidomic profiles in infancy: a population-based cohort study

Background:

The risk of adult onset cardiovascular and metabolic (cardiometabolic) disease accrues from early life. Infection is ubiquitous in infancy and induces inflammation, a key cardiometabolic risk factor, but the relationship between infection, inflammation, and metabolic profiles in early childhood remains unexplored. We investigated relationships between infection and plasma metabolomic and lipidomic profiles at age 6 and 12 months, and mediation of these associations by inflammation.

Methods:

Matched infection, metabolomics, and lipidomics data were generated from 555 infants in a pre-birth longitudinal cohort. Infection data from birth to 12 months were parent-reported (total infections at age 1, 3, 6, 9, and 12 months), inflammation markers (high-sensitivity C-reactive protein [hsCRP]; glycoprotein acetyls [GlycA]) were quantified at 12 months. Metabolic profiles were 12-month plasma nuclear magnetic resonance metabolomics (228 metabolites) and liquid chromatography/mass spectrometry lipidomics (776 lipids). Associations were evaluated with multivariable linear regression models. In secondary analyses, corresponding inflammation and metabolic data from birth (serum) and 6-month (plasma) time points were used.

Results:

At 12 months, more frequent infant infections were associated with adverse metabolomic (elevated inflammation markers, triglycerides and phenylalanine, and lower high-density lipoprotein [HDL] cholesterol and apolipoprotein A1) and lipidomic profiles (elevated phosphatidylethanolamines and lower trihexosylceramides, dehydrocholesteryl esters, and plasmalogens). Similar, more marked, profiles were observed with higher GlycA, but not hsCRP. GlycA mediated a substantial proportion of the relationship between infection and metabolome/lipidome, with hsCRP generally mediating a lower proportion. Analogous relationships were observed between infection and 6-month inflammation, HDL cholesterol, and apolipoprotein A1.

Conclusions:

Infants with a greater infection burden in the first year of life had proinflammatory and proatherogenic plasma metabolomic/lipidomic profiles at 12 months of age that in adults are indicative of heightened risk of cardiovascular disease, obesity, and type 2 diabetes. These findings suggest potentially modifiable pathways linking early life infection and inflammation with subsequent cardiometabolic risk.

Funding:

The establishment work and infrastructure for the BIS was provided by the Murdoch Children’s Research Institute (MCRI), Deakin University, and Barwon Health. Subsequent funding was secured from National Health and Medical Research Council of Australia (NHMRC), The Shepherd Foundation, The Jack Brockhoff Foundation, the Scobie & Claire McKinnon Trust, the Shane O’Brien Memorial Asthma Foundation, the Our Women’s Our Children’s Fund Raising Committee Barwon Health, the Rotary Club of Geelong, the Minderoo Foundation, the Ilhan Food Allergy Foundation, GMHBA, Vanguard Investments Australia Ltd, and the Percy Baxter Charitable Trust, Perpetual Trustees. In-kind support was provided by the Cotton On Foundation and CreativeForce. The study sponsors were not involved in the collection, analysis, and interpretation of data; writing of the report; or the decision to submit the report for publication. Research at MCRI is supported by the Victorian Government’s Operational Infrastructure Support Program. This work was also supported by NHMRC Senior Research Fellowships to ALP (1008396); DB (1064629); and RS (1045161) , NHMRC Investigator Grants to ALP (1110200) and DB (1175744), NHMRC-A*STAR project grant (1149047). TM is supported by an MCRI ECR Fellowship. SB is supported by the Dutch Research Council (452173113).

Stearoyl-CoA Desaturase inhibition reverses immune, synaptic and cognitive impairments in an Alzheimer's disease mouse model

The defining features of Alzheimer’s disease (AD) include alterations in protein aggregation, immunity, lipid metabolism, synapses, and learning and memory. Of these, lipid abnormalities are the least understood. Here, we investigate the role of Stearoyl-CoA desaturase (SCD), a crucial regulator of fatty acid desaturation, in AD pathogenesis. We show that inhibiting brain SCD activity for 1-month in the 3xTg mouse model of AD alters core AD-related transcriptomic pathways in the hippocampus, and that it concomitantly restores essential components of hippocampal function, including dendritic spines and structure, immediate-early gene expression, and learning and memory itself. Moreover, SCD inhibition dampens activation of microglia, key mediators of spine loss during AD and the main immune cells of the brain. These data reveal that brain fatty acid metabolism links AD genes to downstream immune, synaptic, and functional impairments, identifying SCD as a potential target for AD treatment.

Alzheimer’s disease (AD) is characterized by lipid abnormalities which are not well understood. Here, the authors investigate the role of Stearoyl-CoA desaturase (SCD) in a mouse model of AD. They show that inhibiting SCD activity induces major brain and immune cell transcriptional changes and restores dendritic structure and learning and memory.

Involvement of Huanglian Jiedu Decoction on Microglia with Abnormal Sphingolipid Metabolism in Alzheimer's Disease

Background

Abnormal sphingolipid metabolism is closely related to the occurrence and development of Alzheimer’s disease (AD). With heat-clearing and detoxifying effects, Huanglian Jiedu decoction (HLJDD) has been used to treat dementia and improve learning and memory impairments.

Purpose

To study the therapeutic effect of HLJDD on AD as it relates to sphingolipid metabolism.

Methods

The level of sphingolipids in the brains of APP/PS1 mice and in the supernatant of β-amyloid (Aβ)_25–35-induced BV2 microglia was detected by HPLC-QTOF-MS and HPLC-QTRAP-MS techniques, respectively. The co-expression of ionized calcium-binding adapter molecule 1 (Iba1) and Aβ as well as four enzymes related to sphingolipid metabolism, including serine palmitoyltransferase 2 (SPTLC2), cer synthase 2 (CERS2), sphingomyelin phosphodiesterase 1 (SMPD1), and sphingomyelin synthase 1 (SGMS1), in the brains of APP/PS1 mice were evaluated by immunofluorescence double labelling. In addition, real-time quantitative reverse transcription-polymerase chain reaction was conducted to determine the mRNA expression of SPTLC2, CERS2, SMPD1, SGMS1, galactosylceramidase (GALC), and sphingosine kinase 2 (SPHK2) in Aβ_25-35-stimulated BV2 microglia.

Results

Abnormal sphingolipid metabolism was observed both in APP/PS1 mouse brain tissues and Aβ_25-35-stimulated BV2 cells. The levels of sphingosine, sphinganine, sphingosine-1-phosphate, sphinganine-1-phosphate and sphingomyelin were significantly reduced, while the levels of ceramide-1-phosphate, ceramide, lactosylceramide and hexosylceramide significantly increased in Aβ_25-35-stimulated BV2 cells. In AD mice, more microglia were clustered in the Aβ-positive region. The decreased level of SGMS1 and increased levels of CERS2, SPTLC and SMPD1 were also found. In addition, the expressions of SPTLC2, CERS2, and SMPD1 in Aβ_25-35-stimulated BV2 cells were increased significantly, while the expressions of GALC, SPHK2, and SGMS1 were decreased. These changes all showed a significant correction after HLJDD treatment.

Conclusion

HLJDD is a good candidate for treating AD. This study provides a novel perspective on the potential roles of the sphingolipid metabolism in AD.

Clinical lipidomics – A community-driven roadmap to translate research into clinical applications

•

Overview of current state of mass spectrometry based lipidomics.

•

Highlighting ongoing efforts towards harmonization.

•

Invitation to join international community.

Lipid metabolites, beyond triglycerides and cholesterol, have been shown to have vast potential for applications in clinical applications, with substantial societal and economical value. To successfully evolve from the current research-grade methods to assays suitable for routine clinical applications, a harmonization – if not standardization – of these mass spectrometry-based workflows is necessary. Input on clinical needs and technological capabilities must be obtained from all relevant stakeholders, including wet lab scientists, informaticians and data scientists, manufacturers, and medical professionals. In order to build bridges between this diverse group of professionals, the International Lipidomics Society and its Clinical Lipidomics Interest Group were created. This opinion article is intended to provide an overview of international efforts to tackle the issues of workflow harmonization, and to serve as an open invitation for others to join this growing community.

Using the Alzheimer's Disease Neuroimaging Initiative to improve early detection, diagnosis, and treatment of Alzheimer's disease

INTRODUCTION

The Alzheimer's Disease Neuroimaging Initiative (ADNI) has accumulated 15 years of clinical, neuroimaging, cognitive, biofluid biomarker and genetic data, and biofluid samples available to researchers, resulting in more than 3500 publications. This review covers studies from 2018 to 2020.

METHODS

We identified 1442 publications using ADNI data by conventional search methods and selected impactful studies for inclusion.

RESULTS

Disease progression studies supported pivotal roles for regional amyloid beta (Aβ) and tau deposition, and identified underlying genetic contributions to Alzheimer's disease (AD). Vascular disease, immune response, inflammation, resilience, and sex modulated disease course. Biologically coherent subgroups were identified at all clinical stages. Practical algorithms and methodological changes improved determination of Aβ status. Plasma Aβ, phosphorylated tau181, and neurofilament light were promising noninvasive biomarkers. Prognostic and diagnostic models were externally validated in ADNI but studies are limited by lack of ethnocultural cohort diversity.

DISCUSSION

ADNI has had a profound impact in improving clinical trials for AD.

Diabetic hypertriglyceridaemia and Alzheimer's disease: causal or not?

PURPOSE OF REVIEW

To summarize recent findings considering type II diabetes, or metabolic syndrome dyslipidaemia with risk for Alzheimer's disease.

RECENT FINDINGS

Population, genetic, clinical and preclinical studies support the hypothesis of increased risk for Alzheimer's disease in type 2 diabetes mellitus. The mechanisms are unclear. However, recent studies suggest that aberrations in the peripheral metabolism of triglyceride-rich-lipoproteins compromise the brain microvasculature.

SUMMARY

We review the literature of prediabetic metabolic syndrome and type 2 diabetes mellitus as a risk factor for Alzheimer's disease. We focus on a potential association with aberrations in the systemic metabolism of triglyceride-rich-lipoproteins reported over 18 months.

Association Between Blood Biochemical Factors Contributing to Cognitive Decline and B Vitamins in Patients With Alzheimer's Disease

Background

Malnutrition, metabolism stress, inflammation, peripheral organs dysfunction, and B vitamins deficiency significantly contribute to the progression and mortality of Alzheimer's disease (AD). However, it is unclear which blood biochemical indicators are most closely related to cognitive decline and B vitamins deficiency (thiamine, folate, vitamin B12) in patients with AD.

Methods

This was a cross-sectional study of 206 AD patients recruited from six hospitals in China. Thiamine diphosphate (TDP), the bioactive form of thiamine, was measured by high-performance liquid chromatography fluoroscopy (HPLC) at a single center. Levels of biochemical indicators (except TDP) were measured by regular and standard laboratory tests in each hospital. Pearson's rank correlation analysis was used to assess relationships between B vitamins and biochemical indicators. T-test was used to compare the difference between ApoE ε4 and non-ApoE ε4 groups. Differences were considered statistically significant as P < 0.05.

Results

Among the biochemical results, in AD population, malnutrition indicators (erythrocyte, hemoglobin, serum albumin, and total protein) were most significantly associated with cognitive function, as was free triiodothyronine (FT3) levels which had been observed in previous study. Malnutrition and FT3 levels depend on age but not apolipoprotein E (ApoE) genotype. Meanwhile, Among the B vitamins, TDP was the most significantly associated with malnutrition indicators and FT3.

Conclusion

Our results indicated that TDP reduction could be a modifiable risk factor for malnutrition and FT3 that contributed to cognitive decline in AD patients. Correcting thiamine metabolism could serve as an optional therapy target for AD treatment.

Ontogeny of circulating lipid metabolism in pregnancy and early childhood: a longitudinal population study

Background: There is mounting evidence that in utero and early life exposures may predispose an individual to metabolic disorders in later life; and dysregulation of lipid metabolism is critical in such outcomes. However, there is limited knowledge about lipid metabolism and factors causing lipid dysregulation in early life that could result in adverse health outcomes in later life. We studied the effect of antenatal factors such as gestational age, birth weight and mode of birth on lipid metabolism at birth; changes in the circulating lipidome in the first four years of life and the effect of breastfeeding in the first year of life. From this study, we aim to generate a framework for deeper understanding into factors effecting lipid metabolism in early life, to provide early interventions for those at risk of developing metabolic disorders including cardiovascular diseases.

Methods and findings: We performed comprehensive lipid profiling of 1074 mother-child dyads in the Barwon Infant Study (BIS), a population based pre-birth cohort and measured 776 distinct lipid species across 42 lipid classes using ultra high-performance liquid chromatography (UHPLC). We measured lipids in 1032 maternal serum samples at 28 weeks' gestation, 893 cord serum samples at birth, 793, 735, and 511 plasma samples at six, twelve months, and four years, respectively. The lipidome differed between mother and newborn and changed markedly with increasing child's age. Cord serum was enriched with long chain poly-unsaturated fatty acids (LC-PUFAs), and corresponding cholesteryl esters relative to the maternal serum. Alkenylphosphatidylethanolamine species containing LC-PUFAs increased with child's age, whereas the corresponding lysophospholipids and triglycerides decreased. We performed regression analyses to investigate the associations of cord serum lipid species with antenatal factors: gestational age, birth weight, mode of birth and duration of labor. Majority of the cord serum lipids were strongly associated with gestational age and birth weight, with most lipids showing opposing associations. Each mode of birth showed an independent association with cord serum lipids. Breastfeeding had a significant impact on the plasma lipidome in the first year of life, with upto 17-fold increases in a few species of alkyldiaclylglycerols at 6 months of age.

Conclusions: This study sheds light on lipid metabolism in infancy and early childhood and provide a framework to define the relationship between lipid metabolism and health outcomes in early childhood.

Funding Statement: This work was supported by the A*STAR-NHMRC joint call funding (1711624031).

Sphingomyelins and ceramides: possible biomarkers for dementia?

PURPOSE OF REVIEW

Dementia is a public health challenge with no existing cure or early biomarkers. We review the evidence for blood-based measures of sphingomyelins and ceramides as potential novel biomarkers of dementia.

RECENT FINDINGS

In recent years, lipids have been under investigation for their role in neurodegenerative diseases especially dementia and Alzheimer's disease. Increasing evidence from postmortem human brains suggests that alterations in the metabolism of sphingolipids could play a crucial part in dementia. Findings from epidemiological investigations of blood-based sphingomyelins and ceramides have been inconsistent.

SUMMARY

This review focuses on blood-based measures of 10 specific ceramides and sphingomyelins (Cer C16:0, Cer C20:0, Cer C22:0, Cer C24:0, Cer C24:1 and SM C16:0, SM C20:0, SM C22:0, SM C24:0, SM C24:1) in relation to cognition and dementia. On the bais of 15 studies, there was no robust association between ceramide and sphingomyelin levels and prevalent or incident dementia. Cross-sectionally, Cer C16:0 and Cer C24:1 tends to be higher in dementia cases vs. controls.

National pharmacy associations in the commonwealth: current scenario and future needs to maximise effective contributions of the pharmacy profession towards universal health coverage

BACKGROUND

The Commonwealth Pharmacists Association (CPA) is a charity representing pharmacists across the Commonwealth, with the vision of empowering and collaboratively develop the profession and fully utilise the potential of pharmacists to strengthen health systems through supporting better access to, quality and use of medicines and related services. Commonwealth comprises predominantly of low- and middle-income countries, where limited data often exists in pharmacy practice. There is a recognised need across the Commonwealth to focus on developing, implementing and fully utilising pharmacy professional services to progress universal health coverage and achieve the sustainable development goals, particularly in low and middle-income countries; however, currently a knowledge gap exists in understanding the national priorities in Commonwealth nations. CPA is ideally positioned to access to these nations. The aim of this study was thus to explore the priorities and focus areas of NPAs across the Commonwealth and create evidence for a needs-based approach to inform the support that the Commonwealth pharmacists association can collaboratively and strategically provide to its members to progress towards shared goals.

METHODS

Data were collected virtually on Zoom by conducting interviews using a semi-structured interview guide developed for this study with CPA councillors representing NPAs or their equivalents if no official body existed. An inductive, reflexive, thematic analysis was performed for data analysis.

RESULTS

In total, 30 councillors were interviewed from 30 low- and medium-income countries. The three main overarching priority areas identified across respective Commonwealth nations developing extended pharmacy services, improving pharmacy education, and developing and redefining the role of NPAs.

CONCLUSIONS

This novel study highlights the collective priorities for the pharmacy profession across the low and middle-income countries of the Commonwealth and the urgent need for supporting NPAs around the three identified overarching priority areas. The mapped-out priorities will inform an evidence-based approach for the CPA to better support NPAs in their mission through advocacy and practitioner development, to fully harness pharmacists' unique skill set and maximise their contribution to progressing universal health coverage.

Association of Lipidomics Signatures in Blood with Clinical Progression in Preclinical and Prodromal Alzheimer's Disease

BACKGROUND

Lipidomics may provide insight into biochemical processes driving Alzheimer's disease (AD) pathogenesis and ensuing clinical trajectories.

OBJECTIVE

To identify a peripheral lipidomics signature associated with AD pathology and investigate its potential to predict clinical progression.

METHODS

We used Bayesian elastic net regression to select plasma lipid classes associated with the CSF pTau/Aβ42 ratio as a biomarker of AD pathology in preclinical and prodromal AD cases from the ADNI cohort. Consensus clustering of the selected lipid classes was used to identify lipidomic endophenotypes and study their association with clinical progression.

RESULTS

In the APOE4-adjusted model, ether-glycerophospholipids, lyso-glycerophospholipids, free-fatty acids, cholesterol esters, and complex sphingolipids were found to be associated with the CSF pTau/Aβ 42 ratio. We found an optimal number of five lipidomic endophenotypes in the prodromal and preclinical cases, respectively. In the prodromal cases, these clusters differed with respect to the risk of clinical progression as measured by clinical dementia rating score conversion.

CONCLUSION

Lipid alterations can be captured at the earliest phases of AD. A lipidomic signature in blood may provide a dynamic overview of an individual's metabolic status and may support identifying different risks of clinical progression.

Systems modeling of metabolic dysregulation in neurodegenerative diseases

Neurodegenerative diseases (NDDs) encompass a wide range of conditions that arise owing to progressive degeneration and the ultimate loss of nerve cells in the brain and peripheral nervous system. NDDs such as Alzheimer's, Parkinson's, and Huntington's diseases negatively impact both length and quality of life, due to lack of effective disease-modifying treatments. Herein, we review the use of genome-scale metabolic models, network-based approaches, and integration with multiomics data to identify key biological processes that characterize NDDs. We describe powerful systems biology approaches for modeling NDD pathophysiology by leveraging in silico models that are informed by patient-derived multiomics data. These approaches can enable mechanistic insights into NDD-specific metabolic dysregulations that can be leveraged to identify potential metabolic markers of disease and predisease states.

Challenges in LC-MS-based metabolomics for Alzheimer's disease early detection: targeted approaches versus untargeted approaches

BACKGROUND

Alzheimer's disease (AD) is one of the most common causes of dementia in old people. Neuronal deficits such as loss of memory, language and problem-solving are severely compromised in affected patients. The molecular features of AD are Aβ deposits in plaques or in oligomeric structures and neurofibrillary tau tangles in brain. However, the challenge is that Aβ is only one piece of the puzzle, and recent findings continue to support the hypothesis that their presence is not sufficient to predict decline along the AD outcome. In this regard, metabolomic-based techniques are acquiring a growing interest for either the early diagnosis of diseases or the therapy monitoring. Mass spectrometry is one the most common analytical platforms used for detection, quantification, and characterization of metabolic biomarkers. In the past years, both targeted and untargeted strategies have been applied to identify possible interesting compounds.

AIM OF REVIEW

The overall goal of this review is to guide the reader through the most recent studies in which LC-MS-based metabolomics has been proposed as a powerful tool for the identification of new diagnostic biomarkers in AD. To this aim, herein studies spanning the period 2009-2020 have been reported. Advantages and disadvantages of targeted vs untargeted metabolomic approaches have been outlined and critically discussed.

Decreased Levels of Insulin-Like Growth Factor-1 Are Associated with Alzheimer's Disease: A Meta-Analysis

BACKGROUND

Alterations in levels of peripheral insulin-like growth factor-1 (IGF-1) in Alzheimer's disease (AD) have been reported in several studies, and results are inconsistent.

OBJECTIVE

We conducted a meta-analysis to investigate the relationship between peripheral and cerebrospinal fluid IGF-1 levels and AD or mild cognitive impairment (MCI).

METHODS

A systematic search in PubMed, Medline, Web of Science, Embase, and Cochrane Library was conducted and 18 studies were included.

RESULTS

Results of random-effects meta-analysis showed that there was no significant difference between AD patients and healthy control (17 studies; standard mean difference [SMD], -0.01; 95%CI, -0.35 to 0.32) and between MCI patients and healthy control (6 studies; SMD, -0.20; 95%CI, -0.52 to 0.13) in peripheral IGF-1 levels. Meta-regression analyses identified age difference might explain the heterogeneity (p = 0.017). However, peripheral IGF-1 levels were significantly decreased in AD subjects (9 studies; SMD, -0.44; 95%CI, -0.81 to -0.07) and MCI subjects exhibited a decreasing trend (4 studies; SMD, -0.31; 95%CI, -0.72 to 0.11) in studies with sample size≥80. Cerebrospinal fluid IGF-1 levels also significantly decreased in AD subjects (3 studies; SMD, -2.40; 95%CI, -4.36 to -0.43).

CONCLUSION

These findings suggest that decreased peripheral and cerebrospinal fluid IGF-1 levels might be a potential marker for the cognitive decline and progression of AD.