Expression levels of blood microRNAs as biomarker of cognitive decline due to Alzheimer's disease

Studies investigating differential miRNAs expression levels in patients with Alzheimer’s disease (AD) abounded in the last decades and catalysed the interest towards miRNAs as novel non-invasive biomarkers of AD. Chapter 1 provides an overview of AD’s pathogenesis, discusses the evolution of the disease’s definition, and introduces miRNAs. In Chapter 2, a systematic review and a P-value based meta-analysis of 107 studies investigate miRNA expression levels in AD patients. This leads to a prioritisation of 25, 32 and 5 dysregulated miRNAs at study-wide significance in the brain, the blood and the cerebrospinal fluid (CSF) of AD patients, respectively. A pathway enrichment analysis for the top dysregulated miRNAs in the brain confirms their role in regulating biological functions implicated in AD. In Chapter 3, expression levels of the 32 dysregulated miRNAs in the blood and 6 top dysregulated miRNAs in the brain of AD patients, are assessed using real-time quantitative polymerase chain reaction in the blood of cognitively healthy individuals from the CHARIOT-PRO cohort. Low performers on the total Repeatable Battery for the Assessment of Neuropsychological Status scale show downregulation of six miRNAs (hsa-miR-128-3p, hsa-miR-144-5p, hsa-miR-146a-5p, hsa-miR-26a-5p, hsa-miR-29c-3p and hsa-miR-363-3p). Pathway enrichment analysis highlights involvement in pathways initiating early pathogenetic changes in AD. Finally, in chapter 4, whole-genome sequencing data from the Alzheimer’s Disease Neuroimaging Initiative is used to perform an association analysis between polymorphisms within the six miRNAs’ genes and CSF biomarkers of neurodegeneration. A functional annotation of significant variants highlights expression quantitative trait loci, location in enhancer regions and alterations in the binding sites of transcription factors regulating neuronal function. The association of variants located within the same miRNA gene with different markers of neurodegeneration reveals a positive correlation between members of the amyloid cascade and microglial activation in the CSF. The final chapter highlights the clinical relevance of these findings and discusses future perspectives.Open Acces

Patients with geriatric syndromes and anti-amyloid therapies: lack of consideration? An exploratory analysis of the literature.

INTRODUCTION Patients who should benefit from anti-amyloid therapies (AAT) are found across all geriatric settings. Yet, it remains unclear how the use of AAT in patients with geriatric syndromes, such as frailty and polypharmacy, has so far been discussed in the literature. METHODS Articles on aducanumab, gantenerumab, lecanemab, donanemab, crenezumab, solanezumab were retrieved in MEDLINE from inception to July 2023. For each article, identified geriatric relevant terms were assigned to five discussion contexts (eligibility of AAT study population, safety, prescription, patient clinical profile, alternative outcomes measurement). Article type and the involvement of geriatric healthcare professionals as an author were further extracted. RESULTS Out of 538 articles, 23 (4.27%) were published in journals from the geriatric category, 44 (8.18%) included an author affiliated with a geriatric institution. One hundred and sixteen (21.56%) articles included at least one geriatric relevant term, which were mostly discussed in the context of safety and eligibility. Articles mentioning geriatric syndromes were more frequently authored by a geriatric healthcare professional (p = 0.044). DISCUSSION The use of AAT in patients with geriatric syndromes has so far received poor attention in the literature raising concerns on their use in this patient group. The involvement of geriatric healthcare professionals in future studies may increase the relevance of AAT research in patients with geriatric syndromes

Approach for Phased Sequence-Based Genotyping of the Critical Pharmacogene Dihydropyrimidine Dehydrogenase (DPYD).

Pre-treatment genotyping of four well-characterized toxicity risk-variants in the dihydropyrimidine dehydrogenase gene (DPYD) has been widely implemented in Europe to prevent serious adverse effects in cancer patients treated with fluoropyrimidines. Current genotyping practices are largely limited to selected commonly studied variants and are unable to determine phasing when more than one variant allele is detected. Recent evidence indicates that common DPYD variants modulate the functional impact of deleterious variants in a phase-dependent manner, where a cis- or a trans-configuration translates into different toxicity risks and dosing recommendations. DPYD is a large gene with 23 exons spanning nearly a mega-base of DNA, making it a challenging candidate for full-gene sequencing in the diagnostic setting. Herein, we present a time- and cost-efficient long-read sequencing approach for capturing the complete coding region of DPYD. We demonstrate that this method can reliably produce phased genotypes, overcoming a major limitation with current methods. This method was validated using 21 subjects, including two cancer patients, each of whom carried multiple DPYD variants. Genotype assignments showed complete concordance with conventional approaches. Furthermore, we demonstrate that the method is robust to technical challenges inherent in long-range sequencing of PCR products, including reference alignment bias and PCR chimerism

Prospective Study of Ageing Trajectories in the European DO-HEALTH Study.

INTRODUCTION Ageing trajectories range from delayed ageing with extended health to accelerated ageing, with an increased risk of frailty. We evaluated the prevalence and prospective change between health states among community-dwelling European older adults. METHODS This prospective study is a secondary analysis of DO-HEALTH, a randomized trial that included adults aged 70 years and older across 5 European countries. Healthy agers (HA) fulfilled the Nurses' Health Study healthy ageing criteria and accelerated agers were non-HA being at least pre-frail according to the Fried frailty criteria. We assessed the proportion of participants changing between health states over 4 assessments and evaluated the odds of changing to a more favourable category. To increase reliability and avoid regression to the mean, we averaged the first 2 years and compared them to the average of the last 2 years. RESULTS Of 2,157 participants, 12.4% were excluded for meeting both healthy ageing and pre-frailty criteria simultaneously. Among the remaining 1,889 participants (mean age 75.1 years, 60.9% female), 23.1% were initially HA, 44.4% were non-HA but not pre-frail, and 32.6% were pre-frail or frail. Subsequently, 65.3% remained in the same health state, 12.0% improved to a healthier state, and 22.8% progressed to a less advantageous state. After adjusting for sex, study centre, treatment, and body mass index, each year of age was associated with 6% lower odds of improving health states. Women had 35% higher odds than men of following a disadvantageous trajectory. CONCLUSION We observed dynamic trajectories of ageing where transitioning to a healthier state became less likely with advancing age and among women

Prevalence of polypharmacy in community-dwelling older adults from seven centres in five European countries : A cross-sectional study of DO-HEALTH

Objective To investigate the prevalence of polypharmacy and characteristics associated with polypharmacy in older adults from seven European cities. Design Cross-sectional study of baseline data from DO-HEALTH. Setting and participants DO-HEALTH enrolled 2157 community-dwelling adults age 70 and older from seven centres in Europe. Participants were excluded if they had major health problems or Mini-Mental State Examination Score <24 at baseline. Primary outcome measures Extensive information on prescription and over-the-counter medications were recorded. Polypharmacy was defined as the concomitant use of five or more medications, excluding vitamins or dietary supplements. Bivariate and multivariable logistic regression was used to test the association of sociodemographic factors (age, sex, years of education, living situation and city) and health-related indicators (number of comorbidities, cognitive function, frailty status, body mass index (BMI), prior fall, self-rated health and smoking status) with polypharmacy. Results 27.2% of participants reported polypharmacy ranging from 16.4% in Geneva to 60.8% in Coimbra. In the multivariable logistic regression analyses, older age (OR 1.07; 95% CI 1.04 to 1.10), greater BMI (OR 1.09; 95% CI 1.06 to 1.12) and increased number of comorbidities (OR 2.13; 95% CI 1.92 to 2.36) were associated with polypharmacy. Women were less likely to report polypharmacy than men (OR 0.65; 95% CI 0.51 to 0.84). In comparison to participants from Zurich, participants from Coimbra were more likely to report polypharmacy (OR 2.36; 95% CI 1.56 to 3.55), while participants from Geneva or Toulouse were less likely to report polypharmacy ((OR 0.36; 95% CI 0.22 to 0.59 and OR 0.64; 95% CI 0.42 to 0.96), respectively). Living situation, smoking status, years of education, prior fall, cognitive function, self-rated health and frailty status were not significantly associated with polypharmacy. Conclusion Polypharmacy is common among relatively healthy older adults, with moderate variability across seven European cities. Independent of several confounders, being a woman, older age, greater BMI and greater number of comorbidities were associated with increased odds for polypharmacy. Trial registration number NCT01745263

Prevalence of polypharmacy in community-dwelling older adults from seven centres in five European countries: a cross-sectional study of DO-HEALTH.

OBJECTIVE To investigate the prevalence of polypharmacy and characteristics associated with polypharmacy in older adults from seven European cities. DESIGN Cross-sectional study of baseline data from DO-HEALTH. SETTING AND PARTICIPANTS DO-HEALTH enrolled 2157 community-dwelling adults age 70 and older from seven centres in Europe. Participants were excluded if they had major health problems or Mini-Mental State Examination Score <24 at baseline. PRIMARY OUTCOME MEASURES Extensive information on prescription and over-the-counter medications were recorded. Polypharmacy was defined as the concomitant use of five or more medications, excluding vitamins or dietary supplements. Bivariate and multivariable logistic regression was used to test the association of sociodemographic factors (age, sex, years of education, living situation and city) and health-related indicators (number of comorbidities, cognitive function, frailty status, body mass index (BMI), prior fall, self-rated health and smoking status) with polypharmacy. RESULTS 27.2% of participants reported polypharmacy ranging from 16.4% in Geneva to 60.8% in Coimbra. In the multivariable logistic regression analyses, older age (OR 1.07; 95% CI 1.04 to 1.10), greater BMI (OR 1.09; 95% CI 1.06 to 1.12) and increased number of comorbidities (OR 2.13; 95% CI 1.92 to 2.36) were associated with polypharmacy. Women were less likely to report polypharmacy than men (OR 0.65; 95% CI 0.51 to 0.84). In comparison to participants from Zurich, participants from Coimbra were more likely to report polypharmacy (OR 2.36; 95% CI 1.56 to 3.55), while participants from Geneva or Toulouse were less likely to report polypharmacy ((OR 0.36; 95% CI 0.22 to 0.59 and OR 0.64; 95% CI 0.42 to 0.96), respectively). Living situation, smoking status, years of education, prior fall, cognitive function, self-rated health and frailty status were not significantly associated with polypharmacy. CONCLUSION Polypharmacy is common among relatively healthy older adults, with moderate variability across seven European cities. Independent of several confounders, being a woman, older age, greater BMI and greater number of comorbidities were associated with increased odds for polypharmacy. TRIAL REGISTRATION NUMBER NCT01745263

Prevalence of Physical Frailty: Results from the DO-HEALTH Study

Background: Frailty is a geriatric syndrome associated with multiple negative health outcomes. However, its prevalence varies by population and instrument used. We investigated frailty and pre-frailty prevalence by 5 instruments in community-dwelling older adults enrolled to a randomized-controlled trial in 5 European countries. METHODS: Cross-sectional baseline analysis in 2,144 DO-HEALTH participants recruited from Switzerland, Austria, France, Germany, and Portugal with complete data for frailty. Frailty status was assessed by the Physical Frailty Phenotype [PFP], SOF-Frailty Index [SOF-FI], FRAIL-Scale, SHARE-Frailty Instrument [SHARE-FI], and a modified SHARE-FI, and compared by country, age, and gender. Logistic regression was used to determine relevant factors associated with frailty and pre-frailty. RESULTS: Mean age was 74.9 (±4.4) years, 61.6% were women. Based on the PFP, overall frailty and pre-frailty prevalence was 3.0% and 43.0%. By country, frailty prevalence was highest in Portugal (13.7%) and lowest in Austria (0%), and pre-frailty prevalence was highest in Portugal (57.3%) and lowest in Germany (37.1%). By instrument and overall, frailty and pre-frailty prevalence was highest based on SHARE-FI (7.0% / 43.7%) and lowest based on SOF-FI (1.0% / 25.9%). Frailty associated factors were residing in Coimbra (Portugal) [OR 12.0, CI 5.30-27.21], age above 75 years [OR 2.0, CI 1.17-3.45], and female gender [OR 2.8, CI 1.48-5.44]. The same three factors predicted pre-frailty. CONCLUSIONS: Among relatively healthy adults age 70 and older enroled to DO-HEALTH, prevalence of frailty and pre-frailty differed significantly by instrument, country, gender, and age. Among instruments, the highest prevalence of frailty and pre-frailty was documented by the SHARE-FI and the lowest by the SOF-FI

Effects of vitamin D, omega-3 and a simple strength exercise programme in cardiovascular disease prevention: The DO-HEALTH randomized controlled trial

Background: The effects of non-pharmaceutical interventions in the prevention of cardiovascular diseases (CVD) in older adults remains unclear. Therefore, the aim was to investigate the effect of 2000 IU/day of vitamin D$_3$, omega-3 fatty acids (1 g/day), and a simple home strength exercise program (SHEP) (3×/week) on lipid and CVD biomarkers plasma changes over 3 years, incident hypertension and major cardiovascular events (MACE). Methods: The risk of MACE (coronary heart event or intervention, heart failure, stroke) was an exploratory endpoint of DO-HEALTH, incident hypertension and change in biomarkers were secondary endpoints. DO-HEALTH is a completed multicentre, randomised, placebo-controlled, 2 × 2 × 2 factorial design trial enrolling 2157 Europeans aged ≥70 years. Results: Participants' median age was 74 [72, 77] years, 61.7% were women, 82.5% were at least moderately physically active, and 40.7% had 25(OH)D < 20 ng/mL at baseline. Compared to their controls, omega-3 increased HDL-cholesterol (difference in change over 3 years: 0.08 mmol/L, 95% CI 0.05-0.10), decreased triglycerides (-0.08 mmol/L, (95%CI -0.12 to -0.03), but increased total- (0.15 mmol/L, 95%CI 0.09; 0.2), LDL- (0.11 mmol/L, 0.06; 0.16), and non-HDL-cholesterol (0.07 mmol/L, 95%CI 0.02; 0.12). However, neither omega-3 (adjustedHR 1.00, 95%CI 0.64-1.56), nor vitamin D$_3$ (aHR 1.37, 95%CI 0.88-2.14), nor SHEP (aHR 1.18, 95%CI 0.76-1.84) reduced risk of MACE or incident hypertension compared to control. Conclusion: Among generally healthy, active, and largely vitamin D replete, older adults, treatment with omega-3, vitamin D$_3$, and/or SHEP had no benefit on MACE prevention. Only omega-3 supplementation changed lipid biomarkers, but with mixed effects. TRIAL REGISTRATION CLINICALTRIALS

In Silico Models to Validate Novel Blood-Based Biomarkers.

Biological validation of preliminary findings is a key prerequisite in biomarker discovery. In recent years, the development of advanced large-scale sequencing technologies combined with high-throughput computational analysis methods led to the extraction of considerable amount of data from healthy and diseased tissues. Stored in large open-access repositories, these data can be accessed and interrogated by researchers aiming at understanding the biological rationale behind their results. These so called in silico analyses, in opposite to in vitro analyses, have gained increasing importance in recent years, becoming a major component of research projects and publications. However, making sense of the large amount of data available can be challenging and may lead to a misinterpretation of the data. To reduce the dimensionality of this data, recent years have seen the development of statistical m\ethods and advanced graph analytics which help researchers summarize the available data and draw appropriate conclusions. In this chapter we will describe three in silico methods to investigate the biological underpinnings of a panel of seven blood-based biomarkers of Alzheimer's disease

Are patients with cognitive impairment fit to fly? Current evidence and practical recommendations

Background The worldwide prevalence of dementia is increasing and represents a major public health concern. In the last decades, air travel services have undergone an impressive expansion and one of ten passengers is aged 65 years and older. While air travel can be stressful at all ages and health conditions, older individuals with cognitive impairment carry a greater risk for air-travel-related complications. Consequently, demands to general practitioners for assessing their older patient’s fitness to fly are increasing. Methods We conducted a search of the literature in PubMed on the impact of in-flight environmental changes on passengers with cognitive impairment and possible resulting complications. This set the base for a discussion on pharmacological and non-pharmacological interventions aimed at preventing in-flight complications in this vulnerable population. Results While our research strategy identified a total of 11 articles related to older age and air travel, only three focused on passengers with cognitive impairment. Our literature review showed that the airplane environment may lead to a large spectrum of symptoms in passengers of all age groups. However, passengers with cognitive impairment due to neurodegenerative diseases are at increased risk for experiencing the most extreme symptoms such as acute confusional state. Non-pharmacological and pharmacological interventions at different stages of the travel process (before, during and after) can help prevent complications in this vulnerable population. Conclusion The decision to let a patient with cognitive impairment fly requires a solid understanding of the in-flight environmental changes and their impact on older patients with cognitive impairment. Moreover, a sound weighing of the risks and benefits while considering different aspects of the patient’s history is demanded. In this regard, the role of the treating physicians and caregivers is essential along with the support of the medical department of the airline