Unravelling protein aggregation as an ageing related process or a neuropathological response

Protein aggregation is normally associated with amyloidosis, namely motor neurone, Alzheimer’s, Parkinson’s or prion diseases. However, recent results have unveiled a concept of gradual increase of protein aggregation associated with the ageing process, apparently not necessarily associated with pathological conditions. Given that protein aggregation is sufficient to activate stress-response and inflammation, impairing protein synthesis and quality control mechanisms, the former is assumed to negatively affect cellular metabolism and behaviour. In this review the state of the art in protein aggregation research is discussed, namely the relationship between pathology and proteostasis. The role of pathology and ageing in overriding protein quality-control mechanisms, and consequently, the effect of these faulty cellular processes on pathological and healthy ageing, are also addressed.     

Dénutrition du sujet âgé

Malnutrition remains a particularly important issue in elderly. Physiological ageing induces many changes but ageing cannot entirely explain a Protein-Energy Malnutrition (PEM). Nutritionnal screening is indicated once a year in community medicine or in the first 48 hours in case of an acute disease or of hospitalization. The Mini Nutritional Assessment is recommended for screening and for the diagnostic of malnutrition. Possible aetiologies are large and must be investigated in order to be careful not to dismiss curable disease and to be able to take corrective actions. PEM is associated to functional decline, length of stay in hospital and to morbi-mortality. Recommendations for dietary intakes in healthy old subjects are about 30 kcal/kg/day and 1 g/kg/day of protein and are strongly enhanced in case of acute or chronic diseases. The nutritional strategy depends on spontaneous food intake, medical situation, patient profile and opinion. Appropriate nutritional care could reduce morbidity-mortality and prevent functional decline in various disease contexts.     

The effect of ageing on the resolution of inflammation

Ageing is associated with the development of a low-level, systemic, chronic inflammation known as “inflammaging”. This chronic inflammatory state can contribute to diseases of ageing such as sarcopenia and frailty. The presence of inflammaging suggests a failure of the cell clearance mechanisms that ordinarily aid in the resolution of inflammation after pathogen infiltration or tissue injury. This review aims to explore what is known of how the processes involved in the resolution of inflammation might become defective with age.     

Calidad del sueño y déficit de memoria en el envejecimiento sano

ObjectiveTo study the relationship between sleep quality and memory in healthy ageing.MethodsThe study included 99 people older than 50 years (69 women and 30 men; mean age, 68.74 ± 7.18 years) with no associated diseases. Patients completed digital versions of the Word Learning and Visual Paired Associates tests and the Pittsburgh Sleep Quality Index questionnaire to assess the quality of sleep.ResultsPittsburgh Sleep Quality Index score was negatively correlated with Visual Paired Associates and Word Learning test performance. Performance in these 2 memory tests decreased in line with sleep quality. In addition, performance in Visual Paired Associates test was negatively correlated with subjective sleep quality, duration, and sleep disturbances. Performance on the Word Learning test was negatively correlated with subjective sleep quality and efficiency. Participants’ sex showed a weak effect on Visual Paired Associates performance and sleep latency.ConclusionsMedical professionals working with elderly patients should take into consideration the effect of poor sleep quality on memory. Cognitive impairment in these patients may be a manifestation of a neuroendocrine imbalance due to a disrupted circadian rhythm. More research is needed to prove this hypothesis.     

Sleep and brain morphological changes in the eighth decade of life

ObjectiveSleep is important for brain health. We analysed associations between usual sleep habits and magnetic resonance imaging (MRI) markers of neurodegeneration (brain atrophy), vascular damage (white matter hyperintensities, WMH) and waste clearance (perivascular spaces, PVS) in older community-dwelling adults.MethodWe collected self-reported usual sleep duration, quality and medical histories from the Lothian Birth Cohort 1936 (LBC1936) age 76 years and performed brain MRI. We calculated sleep efficiency, measured WMH and brain volumes, quantified PVS, and assessed associations between sleep measures and brain markers in multivariate models adjusted for demographic and medical history variables.ResultsIn 457 subjects (53% males, mean age 76 ± 0.65 years), we found: brain and white matter loss with increased weekend daytime sleep (β = −0.114, P = 0.03; β = −0.122, P = 0.007 respectively), white matter loss with less efficient sleep (β = 0.132, P = 0.011) and PVS increased with interrupted sleep (OR 1.84 95% CI, P = 0.025).ConclusionCross-sectional associations of sleep parameters with brain atrophy and more PVS suggest adverse relationships between usual sleep habits and brain health in older people that should be evaluated longitudinally.     

Postural adjustments in anticipation of predictable perturbations allow elderly fallers to achieve a balance recovery performance equivalent to elderly non-fallers

BackgroundIn numerous laboratory-based perturbation experiments, differences in the balance recovery performance of elderly fallers and non-fallers are moderate or absent. This performance may be affected by the subjects adjusting their initial posture in anticipation of the perturbation.Research questions: Do elderly fallers and non-fallers adjust their posture in anticipation of externally-imposed perturbations in a laboratory setting? How does this impact their balance recovery performance?Methods21 elderly non-fallers, 18 age-matched elderly fallers and 11 young adults performed both a forward waist-pull perturbation task and a Choice Stepping Reaction Time (CSRT) task. Whole-body kinematics and ground reaction forces were recorded. For each group, we evaluated the balance recovery performance in the perturbation task, change in initial center of mass (CoM) position between the CSRT and the perturbation task, and the influence of initial CoM position on task performance.ResultsThe balance recovery performance of elderly fallers was equivalent to elderly non-fallers (p > 0.5 Kolmogorov-Smirnov test). All subject groups anticipated forward perturbations by shifting their CoM backward compared to the CSRT task (young: 2.1% of lower limb length, elderly non-fallers: 2.7%, elderly fallers: 2.2%, Hodges-Lehmann estimator, p < 0.001 Mann-Whitney U). This backward shift increases the probability of resisting the traction without taking a step.SignificanceThe ability to anticipate perturbations is preserved in elderly fallers and may explain their preserved balance recovery performance in laboratory-based perturbation tasks. Therefore, future fall risk prediction studies should carefully control for this postural strategy, by interleaving perturbations of different directions for example.     

Free GP care and psychological health: Quasi-experimental evidence from Ireland

There is considerable ambiguity in the literature on the effect of health insurance on health. While the majority of previous analyses have examined physical health outcomes, analyses of the broader dimensions of health such as psychological health and wellbeing have been less frequent. Using data from the Irish Longitudinal Study on Ageing (TILDA) and a difference-in-differences research design, we examine the impact of free general practitioner (GP) care on psychological health among the older population and explore potential mechanisms. While we find no impact of public health insurance expansions on quality of life, life satisfaction, depression, and worry, the removal of GP fees for all those 70+ leads to a significantly lower level of perceived stress. The impact is mainly driven by poorer, sicker and single individuals. Further analyses show that removing GP fees leads to greater access to GP services and lower levels of financial stress.