Current Aging Science - Volume 14, Issue 3, 2021

It is established that the gut microbiota has a significant influence on Alzheimer’s disease. In turn, both the disease and the microbiota are affected by biological variables associated with modern lifestyles. Examination of the potential interrelationship among these three factors and on the role played by lifestyles in gut dysbiosis-induced pathologies of Alzheimer’s disease are limited. Deciphering these connections will provide insights into the pathogenesis and therapeutic strategies for Alzheimer’s disease. Specifically, based on this trilateral relationship, various nonpharmacological interventive strategies targeting the gut microbiota can be developed. This review fills this gap by presenting the latest evidence for the modulative role of modern lifestyle on the gut microbiota and its relevance to Alzheimer’s disease, with a discussion on the limitations of current research and future directions.

Background: Currently, the focus of anti-aging research has been changed from geriatrics to biogerontology. This has taken anti-aging strategies from cost-effective but palliative therapeutics to active, molecular approaches. Outline: Over the years, a large body of basic gerontological research has indicated that the process of biological aging is closely associated with genetic factors. This leads to the development of various gene therapies such as RNA interference technology and results in a subsequent need for translating laboratory achievements into clinical applications. The translation has been a tremendous challenge at this stage with respect to the practicality, safety, and effectiveness of the genetic manipulation techniques. Objective: This review summarizes the current development of anti-aging strategies and the progress in the translation of laboratory achievements into clinical applications, highlights challenges encountered, and provides a prospective outlook for future anti-aging research.

Background: Since age is the major risk factor for chronic diseases and mortality, it seems mistaken that older adults have lower basal temperature than young individuals. Many confounding factors could hinder the achievement of a consensus, such as the different sites of measurement, control of basal conditions, health conditions, age difference compared, sex, and others. Objective: The aim was to meta-analyze previous studies in order to find a consensus regarding the effects of aging on body temperature in humans, considering different types of temperature assessments, age difference and sex. Methods: A systematic search was performed in PubMed and 16 studies comparing basal temperature between older and young adults were meta-analyzed. Results: Older adults have significantly lower body temperature than young adults (-0.17 °C (-0.30; -0.03), p=0.04). Considering the different sites of measure, while core temperature tended to be lower in older adults (-0.13 °C (-0.27; 0.01), p=0.07), and skin temperature was not different (-0.21 °C (-0.5; 0.08), p=0.15). The aging effects were more prominent in men when assessed by oral temperature and when compared between higher age difference. Conclusion: Indeed, there is a small reduction in overall temperature with aging, drove by the reduction in core temperature rather than skin temperature. The confirmation of these findings by this meta-analysis, now provide the base for the development of strategies to face the impairment in thermoregulation and metabolic efficiency with aging.

Aims: The aim of the study was to assess the activation of prefrontal cortex during sustained attention task in young and middle aged adults using Functional near infrared spectroscopy system. Background: Sustained Attention (SA) is a construct of cognition that tends to decline with age. There is a paucity of literature regarding the neural correlates of SA in middle age, a link between young and old age. Objective: This study evaluated the differences in SA ability and its neural correlates using fNIRS between young and middle aged adults. Methods: 38 young and 25 middle aged adults were evaluated for the changes in neural correlates (oxy and deoxy haemoglobin concentration in prefrontal cortex) during a SA task known as cognitrone. Results: The results obtained showed that young adults performed significantly better than middle aged adults on the SA task with no gender difference in their performance. There was a significant difference in the prefrontal activation pattern between young and middle aged adults. We found right prefrontal dominance in young adults and left prefrontal dominance in middle aged adults. Conclusion: This study concludes that the ability to maintain SA diminishes with age, advancing from young to middle age. Hemodynamic findings confirmed significant differences in neural resources in the prefrontal cortical areas between young and middle age.

Background: A relationship between body size and longevity has long been appreciated within eukaryotes, especially vertebrates. Introduction: In general, the large size is associated with increased longevity among species of mammals and birds but is associated with decreased longevity within individual species such as dogs and mice. In this study, we examined the relationship between measures of individual body size and longevity in a captive population of speckled cockroaches (Nauphoeta cineria). Methods: Newly molted adults of both sexes were removed from a mass colony housed in multiple terraria and housed individually with food and water provided ad libitum for the duration of their lifespan. Thrice weekly, the status (i.e., live/dead) of individual cockroaches was noted for the duration of the study. Individuals found dead were weighed and measured to obtain body mass and morphometric measures, and the age at the time of death was recorded. The relationship between body size and lifespan was assessed. Results: Contrary to what is commonly seen within vertebrates, large cockroaches were longerlived than their smaller counterparts. Specifically, body mass, body length, and pronotum width were all significantly correlated with the age at death in a mixed population of males and females (n = 94). In addition, we found that the longevity of a historically larger population in terms of both body mass and body length was significantly longer-lived than the population used in this study. Conclusion: These data indicate there is a significant interaction between body size and aging in this species and that increased size results in a survival advantage. There is evidence in the literature indicating that a positive relationship between size and longevity may be common in insects.

Aims: Lipoprotein (a) deposition in coronary vascular plaques and cerebral vessels is a recognized risk factor for cardiovascular disease, and research supports its role as a “repair factor” in vascular walls weakened by vitamin C deficiency. Background: Humans depend on dietary vitamin C as an important antioxidant and as a cofactor in collagen synthesis, yet are prone to vitamin C deficiency. The brain is the one with the highest vitamin C content, owing to its high oxygen consumption and oxidative stress. It has been shown that brain aging is accompanied by accumulated oxidative damage, which can lead to memory decline and neurological diseases. Objective: Our transgenic mouse, Gulo (-/-); Lp(a)+, presents a unique model for the study of key aspects of human metabolism with respect to a lack of internal vitamin C synthesis and the production of human lipoprotein(a). Methods: This mouse model was used in our study to investigate the effects of prolonged intake of low and high levels of vitamin C, at different ages, on oxidative damage, cholesterol levels and lipoprotein( a) deposition in the brain. Result: The results show that a long-term high vitamin C intake is important in maintaining brain cholesterol homeostasis and preventing oxidative damage in Gulo(-/-);Lp(a)+ mice as they age. Moreover, we observed that the formation of brain lipoprotein(a) deposits was negatively correlated with brain level of vitamin C, thereby confirming its role as a stability factor for an impaired extracellular matrix. Conclusion: Our study emphasizes the critical role of vitamin C in protecting brain health as we age. Other: Our findings show that optimal vitamin C intake from early life to old age is important for brain health as it prevents oxidative stress damage and maintains cholesterol homeostasis in the brain. More importantly, the negative correlation between brain ascorbic levels and the formation of Lp(a) deposit on the choroid plexus further emphasizes the critical role of vitamin C in protecting brain health throughout the normal aging process.

Background: Age is related to a decline in muscle mass and physical function in both respiratory and peripheral muscle strength, which could lead to mobility and mortality. In addition, older people have suffered from one or multiple chronic conditions in particular in type 2 Diabetes Mellitus (type 2 DM). However, a few studies have reported the relationship between sarcopenic elderly and respiratory and peripheral muscle strengths in type 2DM. Objective: To explore the prevalence of sarcopenia in type 2 DM elderly people among community- dwelling patients and the relationships with peripheral and respiratory muscle loss in sarcopenic type 2 DM older patients. Methods: A total of 330 older individuals were recruited from community-dwelling centers. Respiratory muscle and quadriceps muscle were assessed. According to the defined criteria for sarcopenia (defined by Asian Working Group for Sarcopenia), muscle mass, gait speed (six-meter walk test), and handgrip strength were examined. Results: Of 330 elderly people, 82 volunteers had a history of type 2 DM. Participants with type 2DM had a risk for sarcopenia (odds ratio= 2.324, 95% CI=1.251-4.317). The prevalence of sarcopenia was 25.61% among older participants with type 2 DM. In addition, decreased respiratory muscle strength and quadriceps muscle strength were observed in type 2 DM with sarcopenia compared to type 2 DM with non-sarcopenia. These relationships also remained after controlling for age and sex. Conclusion: Sarcopenia in type 2 DM leads to a decrease in respiratory muscle and peripheral muscle strength.

Background: The use of symptomatic slow-acting drugs for osteoarthritis (OA) (e.g., glucosamine, chondroitin) is largely debated in the scientific literature. Indeed, multiple formulations of these agents are available, both as pharmaceutical-grade products and as nutritional supplements , but while all preparations may claim to deliver a therapeutic effect, not all are supported by clinical evidence. Moreover, few data are available regarding the cost-effectiveness of all these formulations. Usually, access to individual patient data is required to perform economic evaluations of treatments, but it can be challenging to obtain. We previously developed a model to simulate individual health utility scores from aggregated data obtained from published OA trials. Objective: In the present study, using our new simulation model, we investigated the costeffectiveness of different glucosamines used in Germany. Methods: We used our validated model to simulate the utility scores of 10 published trials that used different glucosamine preparations. Using the simulated utility scores, the quality-adjusted life years (QALYs) were calculated using the area-under-the-curve method. We used the 2018 public costs of glucosamine products available in Germany to calculate the Incremental Cost/Effectiveness Ratio (ICER). We performed analyses for pharmaceutical-grade Crystalline Glucosamine Sulfate (pCGS) and other formulations of glucosamine (OFG). A cost-effectiveness cut-off of 30,000 /QALY was considered. Results: Of 10 studies in which utility was simulated, four used pCGS, and six used OFG. The ICER analyses showed that pCGS was cost-effective compared to a placebo, with an ICER of 4489 /QALY at month 3, 4112 /QALY at month 6, and 9983 /QALY at year 3. The use of OFG was not cost-effective at any of the time points considered. Conclusion: Using our previously published model to simulate the individual health utility scores of patients, we showed that, in the German context, the use of pCGS could be considered costeffective, while the use of OFG could not. These results highlight the importance of the formulation of glucosamine.