The many facets of brain aging

The Role of Nutraceuticals and Functional Foods in Mitigating Cellular Senescence and Its Related Aspects: A Key Strategy for Delaying or Preventing Aging and Neurodegenerative Disorders

As life expectancy continues to increase, it becomes increasingly important to extend healthspan by targeting mechanisms associated with aging. Cellular senescence is recognized as a significant contributor to aging and neurodegenerative disorders. This review examines the emerging role of nutraceuticals and functional foods as potential modulators of cellular senescence, which may, in turn, influence the development of neurodegenerative diseases. An analysis of experimental studies indicates that bioactive compounds, including polyphenols, vitamins, and spices, possess substantial antioxidants, anti-inflammatory and epigenetic properties. These nutritional senotherapeutic agents effectively scavenge reactive oxygen species, modulate gene expression, and decrease the secretion of senescence-associated secretory phenotype factors, minimizing cellular damage. Nutraceuticals can enhance mitochondrial function, reduce oxidative stress, and regulate inflammation, key factors in aging and diseases like Alzheimer's and Parkinson's. Furthermore, studies reveal that specific bioactive compounds can reduce senescence markers in cellular models, while others exhibit senostatic and senolytic properties, both directly and indirectly. Diets enriched with these nutraceuticals, such as the Mediterranean diet, have been correlated with improved brain health and the deceleration of aging. Despite these promising outcomes, direct evidence linking these compounds to reducing senescent cell numbers remains limited, highlighting the necessity for further inquiry. This review presents compelling arguments for the potential of nutraceuticals and functional foods to promote longevity and counteract neurodegeneration by exploring their molecular mechanisms. The emerging relationship between dietary bioactive compounds and cellular senescence sets the stage for future research to develop effective preventive and therapeutic strategies for age-related diseases.

Age-Dependent Changes of the Sylvian Fissure Configuration

OBJECTIVE

To investigate age-related morphological changes of the Sylvian fissure (SF) and their implications for neurosurgical procedures.

METHODS

A cohort of 150 individuals across the age groups 10-20, 40-50, and 80-90 years was analyzed using Brainlab software for 3-dimensional visualization and volumetric analysis of the SF and various brain regions. We compared SF volumes between age groups and investigated dynamic changes in SF configuration over time. Correlation analyses were performed to identify how atrophy in specific brain regions affects the SF volume and configuration.

RESULTS

Atrophy was evident in all measured regions of the brain. The frontoparietal lobe underwent the strongest atrophy, while the occipital lobe showed the least. Each age group exhibited a consistent distribution of lobe volumes, although a marginal decrease in frontoparietal lobe proportion was observed in the groups of higher age. The annual atrophy rate in the frontoparietal and temporal lobes was steady. Additionally, ventricular expansion, which may influence white matter atrophy patterns, correlated with age. A consistent increase in SF volume in relation to the intracranial volume was observed across all age groups, with a notable increase in SF volume in older patients. This expansion, especially at the anterior-superior point, might be influenced by gravity, cerebral elasticity, and lobe torque.

CONCLUSIONS

Our investigation highlights the significance of age-dependent changes in SF volume and configuration due to brain atrophy throughout life. These changes, influenced by physical factors, underscore the need for tailored surgical approaches. Additionally, brain pathologies affecting volume could significantly alter SF configuration.

Age-related volume decrease in subcortical gray matter is a part of healthy brain aging in men

BACKGROUND

With the global population aging, the number of individuals over 60 is expected to double by 2050. Brain volume increases until age 13, stabilizes between 18 and 35, then declines by 0.2% annually. Magnetic resonance imaging (MRI) studies highlight significant gray matter atrophy, necessitating differentiation between normal aging and neurodegeneration.

AIMS

This study assessed the impact of aging on subcortical gray matter in healthy males to identify biomarkers of physiological aging.

METHODS

A retrospective study of 106 healthy males who underwent brain MRI from 2012 to 2016, divided into two age groups: younger and older than 35 years. MRI scans were performed using a 3 T machine, and volumetric analysis was conducted with VolBrain software. Subcortical gray matter volumes were compared between groups. The Shapiro-Wilk test evaluated normality. Student's t-test and Mann-Whitney U test were used for statistical analysis, with significance defined as p < 0.05.

RESULTS

Total intracranial volume was comparable between age groups (p = 0.527). Significant volume reductions (p < 0.05) were observed in subcortical gray matter structures, including the nucleus accumbens, caudate nucleus, globus pallidus, putamen, thalamus, and ventral diencephalon, particularly on the right side in the elderly group.

CONCLUSIONS

Subcortical gray matter volume in healthy males shows significant differences between older and younger individuals (p < 0.05), with asymmetrical reduction and certain structures on the right aging more rapidly. These findings are significant for distinguishing healthy aging from neurodegeneration.

Morphological and Metabolic Features of Brain Aging in Rodents, Ruminants, Carnivores, and Non-Human Primates

Brain aging in mammals is characterized by morphological and functional changes in neural cells. Macroscopically, this process, leading to progressive cerebral volume loss and functional decline, includes memory and motor neuron deficits, as well as behavioral disorders. Morphologically, brain aging is associated with aged neurons and astrocytes, appearing enlarged and flattened, and expressing enhanced pH-dependent β-galactosidase activity. Multiple mechanisms are considered hallmarks of cellular senescence in vitro, including cell cycle arrest, increased lysosomal activity, telomere shortening, oxidative stress, and DNA damage. The most common markers for senescence identification were identified in (i) proteins implicated in cell cycle arrest, such as p16, p21, and p53, (ii) increased lysosomal mass, and (iii) increased reactive oxygen species (ROS) and senescence-associated secretory phenotype (SASP) expression. Finally, dysfunctional autophagy, a process occurring during aging, contributes to altering brain homeostasis. The brains of mammals can be studied at cellular and subcellular levels to elucidate the mechanisms on the basis of age-related and degenerative disorders. The aim of this review is to summarize and update the most recent knowledge about brain aging through a comparative approach, where similarities and differences in some mammalian species are considered.

Inflammaging and Brain Aging

Progress made by the medical community in increasing lifespans comes with the costs of increasing the incidence and prevalence of age-related diseases, neurodegenerative ones included. Aging is associated with a series of morphological changes at the tissue and cellular levels in the brain, as well as impairments in signaling pathways and gene transcription, which lead to synaptic dysfunction and cognitive decline. Although we are not able to pinpoint the exact differences between healthy aging and neurodegeneration, research increasingly highlights the involvement of neuroinflammation and chronic systemic inflammation (inflammaging) in the development of age-associated impairments via a series of pathogenic cascades, triggered by dysfunctions of the circadian clock, gut dysbiosis, immunosenescence, or impaired cholinergic signaling. In addition, gender differences in the susceptibility and course of neurodegeneration that appear to be mediated by glial cells emphasize the need for future research in this area and an individualized therapeutic approach. Although rejuvenation research is still in its very early infancy, accumulated knowledge on the various signaling pathways involved in promoting cellular senescence opens the perspective of interfering with these pathways and preventing or delaying senescence.

Natural Compounds for Preventing Age-Related Diseases and Cancers

Aging is a multifaceted process influenced by hereditary factors, lifestyle, and environmental elements. As time progresses, the human body experiences degenerative changes in major functions. The external and internal signs of aging manifest in various ways, including skin dryness, wrinkles, musculoskeletal disorders, cardiovascular diseases, diabetes, neurodegenerative disorders, and cancer. Additionally, cancer, like aging, is a complex disease that arises from the accumulation of various genetic and epigenetic alterations. Circadian clock dysregulation has recently been identified as an important risk factor for aging and cancer development. Natural compounds and herbal medicines have gained significant attention for their potential in preventing age-related diseases and inhibiting cancer progression. These compounds demonstrate antioxidant, anti-inflammatory, anti-proliferative, pro-apoptotic, anti-metastatic, and anti-angiogenic effects as well as circadian clock regulation. This review explores age-related diseases, cancers, and the potential of specific natural compounds in targeting the key features of these conditions.

Correlations between Gustatory, Olfactory, Cognitive Function, and Age in Healthy Women

Aging is a progressive physiological degeneration associated with a decline in chemosensory processes and cognitive abilities and a reduction in synaptic plasticity. The biological bases of ageing are still not completely understood, and many theories have been proposed. This study aimed to evaluate the occurrence of age-related changes affecting the chemosensory function (gustatory and olfactory) and general cognitive abilities and their potential associations in women. To this aim, 319 women (the age ranging from 18 to 92 years) were recruited and divided into four different age groups: 18-34 years, 35-49 years, 50-64 years, and ≥65 years. Our results confirmed that in women, gustatory, olfactory, and cognitive functions decline, though in a different manner during aging. Olfactory and cognitive function showed a slight decline along the first three age classes, with a dramatic decrease after age 65 years, while gustatory function decreased more gradually. Olfactory and gustatory deficits may have a high degree of predictivity for general cognitive function as well as for specific cognitive subdomains such as visuospatial/executive abilities, language, memory, and attention. Our study highlighted the importance of using chemosensory assessments for the early diagnosis of cognitive decline and for the development of appropriate personalized risk prevention strategies.

ANTsX neuroimaging-derived structural phenotypes of UK Biobank

UK Biobank is a large-scale epidemiological resource for investigating prospective correlations between various lifestyle, environmental, and genetic factors with health and disease progression. In addition to individual subject information obtained through surveys and physical examinations, a comprehensive neuroimaging battery consisting of multiple modalities provides imaging-derived phenotypes (IDPs) that can serve as biomarkers in neuroscience research. In this study, we augment the existing set of UK Biobank neuroimaging structural IDPs, obtained from well-established software libraries such as FSL and FreeSurfer, with related measurements acquired through the Advanced Normalization Tools Ecosystem. This includes previously established cortical and subcortical measurements defined, in part, based on the Desikan-Killiany-Tourville atlas. Also included are morphological measurements from two recent developments: medial temporal lobe parcellation of hippocampal and extra-hippocampal regions in addition to cerebellum parcellation and thickness based on the Schmahmann anatomical labeling. Through predictive modeling, we assess the clinical utility of these IDP measurements, individually and in combination, using commonly studied phenotypic correlates including age, fluid intelligence, numeric memory, and several other sociodemographic variables. The predictive accuracy of these IDP-based models, in terms of root-mean-squared-error or area-under-the-curve for continuous and categorical variables, respectively, provides comparative insights between software libraries as well as potential clinical interpretability. Results demonstrate varied performance between package-based IDP sets and their combination, emphasizing the need for careful consideration in their selection and utilization.

ANTsX neuroimaging-derived structural phenotypes of UK Biobank

UK Biobank is a large-scale epidemiological resource for investigating prospective correlations between various lifestyle, environmental, and genetic factors with health and disease progression. In addition to individual subject information obtained through surveys and physical examinations, a comprehensive neuroimaging battery consisting of multiple modalities provides imaging-derived phenotypes (IDPs) that can serve as biomarkers in neuroscience research. In this study, we augment the existing set of UK Biobank neuroimaging structural IDPs, obtained from well-established software libraries such as FSL and FreeSurfer, with related measurements acquired through the Advanced Normalization Tools Ecosystem. This includes previously established cortical and subcortical measurements defined, in part, based on the Desikan-Killiany-Tourville atlas. Also included are morphological measurements from two recent developments: medial temporal lobe parcellation of hippocampal and extra-hippocampal regions in addition to cerebellum parcellation and thickness based on the Schmahmann anatomical labeling. Through predictive modeling, we assess the clinical utility of these IDP measurements, individually and in combination, using commonly studied phenotypic correlates including age, fluid intelligence, numeric memory, and several other sociodemographic variables. The predictive accuracy of these IDP-based models, in terms of root-mean-squared-error or area-under-the-curve for continuous and categorical variables, respectively, provides comparative insights between software libraries as well as potential clinical interpretability. Results demonstrate varied performance between package-based IDP sets and their combination, emphasizing the need for careful consideration in their selection and utilization.

Does the Loss of Teeth Have an Impact on Geriatric Patients’ Cognitive Status?

Significant changes in the microstructure of the brain cause dementia and other mental declines associated with aging and disease. Although research has established a connection between oral health and dementia, the underlying pathologic mechanisms are still unknown. Aim: Our aim was to evaluate dentures’ impact on the cognitive state of geriatric patients. Material and methods: A total of 108 individuals seeking treatment at the Faculty of Dental Medicine in Iasi, Romania, participated in the study, which ran from May 2022 to October 2022. Cognitive dysfunction was assessed using the Mini-Mental State Examination. The acquired data were analyzed with IBM SPSS 26.0, and the p-value was set at 0.05. Results: The average value of the MMSE score was 21.81 ± 3.872. Differences between groups of wearer/non-wearer subjects were statistically significant for most of the questions in the questionnaire. Linear regression analysis showed that individuals with a high MMSE score have prosthodontic treatment. A decrease in the MMSE score is associated with a decrease in masticatory efficiency (B = 1.513, p = 0.268). Conclusions: This study provides further evidence that tooth loss is associated with worse cognitive performance. It is thus conceivable that the necessary effects can be achieved by increasing the efforts dedicated to preventing tooth loss in the adult population.

Brain aging mechanisms with mechanical manifestations

Brain aging is a complex process that affects everything from the subcellular to the organ level, begins early in life, and accelerates with age. Morphologically, brain aging is primarily characterized by brain volume loss, cortical thinning, white matter degradation, loss of gyrification, and ventricular enlargement. Pathophysiologically, brain aging is associated with neuron cell shrinking, dendritic degeneration, demyelination, small vessel disease, metabolic slowing, microglial activation, and the formation of white matter lesions. In recent years, the mechanics community has demonstrated increasing interest in modeling the brain's (bio)mechanical behavior and uses constitutive modeling to predict shape changes of anatomically accurate finite element brain models in health and disease. Here, we pursue two objectives. First, we review existing imaging-based data on white and gray matter atrophy rates and organ-level aging patterns. This data is required to calibrate and validate constitutive brain models. Second, we review the most critical cell- and tissue-level aging mechanisms that drive white and gray matter changes. We focuse on aging mechanisms that ultimately manifest as organ-level shape changes based on the idea that the integration of imaging and mechanical modeling may help identify the tipping point when normal aging ends and pathological neurodegeneration begins.

Biological and environmental predictors of heterogeneity in neurocognitive ageing: Evidence from Betula and other longitudinal studies

Individual differences in cognitive performance increase with advancing age, reflecting marked cognitive changes in some individuals along with little or no change in others. Genetic and lifestyle factors are assumed to influence cognitive performance in ageing by affecting the magnitude and extent of age-related brain changes (i.e., brain maintenance or atrophy), as well as the ability to recruit compensatory processes. The purpose of this review is to present findings from the Betula study and other longitudinal studies, with a focus on clarifying the role of key biological and environmental factors assumed to underlie individual differences in brain and cognitive ageing. We discuss the vital importance of sampling, analytic methods, consideration of non-ignorable dropout, and related issues for valid conclusions on factors that influence healthy neurocognitive ageing.