Biology subjects

Maier, A. B.

Publications and source records attributed to Maier, A. B..

3 recordsLinked to original sources

bioRxiv2024

Gut metagenomes of Asian octogenarians reveal metabolic potential expansion and distinct microbial species associated with aging phenotypes

While rapid demographic changes in Asia are driving the incidence of chronic diseases related to aging, the limited availability of high-quality in vivo data hampers our ability to understand complex multi-factorial contributions, including gut microbial, to healthy aging. Leveraging the availability of a well-phenotyped cohort of community-living octogenarians in Singapore, we used deep shotgun metagenomic sequencing to do high-resolution taxonomic and functional characterization of their gut microbiomes (n=234). Joint species-level analysis with other Asian cohorts identified a distinct age-associated shift in Asian gut metagenomes, characterized by a reduction in microbial richness, and enrichment of specific Alistipes and Bacteroides species (e.g. Alistipes shahii and Bacteroides xylanisolvens). Functional pathway analysis confirmed that these changes correspond to a metabolic potential expansion in aging towards alternate pathways that synthesize and utilize amino-acid precursors, relative to the dominant microbial guilds that typically produce butyrate in the gut from pyruvate (e.g. Faecalibacterium prausnitzii, Roseburia inulinivorans). Extending these observations to key clinical markers helped identify >10 robust gut microbial associations to inflammation, cardiometabolic and liver health, including potential probiotic species such as Parabacteroides goldsteinii and pathobionts such as Klebsiella pneumoniae, highlighting the role of the microbiome as biomarkers and potential intervention targets for promoting healthy aging.

genomics↗

bioRxiv2023

Therapeutic effect of dietary interventions on senescence in animals and humans: A systematic review

BackgroundCellular senescence is a permanent state of cell cycle arrest and has been regarded as a therapeutic target for ageing and age-related diseases. Several senotherapeutic agents have been proposed, including compounds derived from natural products which hold the translational potential to promote healthy ageing. It is largely unclear whether cellular senescence could be targeted by dietary interventions. This systematic review examined diets and dietary ingredients and their association with cellular senescence load in animal models and humans, with an intent to identify dietary interventions with senotherapeutic potential. MethodsThe databases PubMed and Embase were systematically searched for key terms related to cellular senescence, senescence markers, diets, nutrients and bioactive compounds. Intervention and observational studies on human and animal models investigating the effects of diets or dietary ingredients via oral administration on cellular senescence load were included. The studies were screened using the Covidence systematic review software. Study design, methods and results were extracted. Biomaterials used for senescence detection were categorized into physiological systems. The SYRCLEs risk of bias tool and Cochrane risk of bias tool v2.0 were used to assess the risk of bias for animal and human studies respectively. ResultsOut of 5707 identified articles, 82 articles consisting of 78 animal studies and 4 human studies aimed to reduce cellular senescence load using dietary interventions. In animal studies, the most-frequently used senescence model was normal ageing (26 studies), followed by D- galactose-induced models (17 studies). Resveratrol (8 studies), vitamin E (4 studies) and soy protein isolate (3 studies) showed positive effects on reducing the level of senescence markers such as p53, p21, p16 and senescence-associated {beta}-galactosidase in various tissues of physiological systems. In three out of four human studies, ginsenoside Rg1 had no positive effect on reducing senescence in muscle tissues after exercise. The risk of bias for both animal and human studies was largely unclear. ConclusionResveratrol, vitamin E and soy protein isolate are promising senotherapeutics studied in animal models. Studies testing dietary interventions with senotherapeutic potential in humans are limited and translation is highly warranted.

cell biology↗

bioRxiv2018

Tasks and responsibilities in physical activity promotion of older patients during hospitalization: A nurse perspective

ObjectiveTo investigate how nurses perceive tasks and responsibilities in promoting physical activity during hospitalization of older patients and which factors are of influence.\n\nDesignObservational cohort study\n\nSetting and participantsOne hundred and eight nurse students, nurses and nurse supervisors employed by an academic Dutch teaching hospital participated in a questionnaire survey and 51 nurses took part in a subsequent in-depth interview.\n\nMeasuresData were collected on tasks and responsibilities in physical activity promotion and their influencing factors as perceived by nurses. Descriptive statistics were used to analyze the data from the questionnaire survey and a deductive approach with directed content analysis was used for the data from the interviews.\n\nResultsNurses perceived to have a dominant role in physical activity promotion of older patients during hospitalization. Ninety percent of the nurses stated to be responsible for physical activity promotion and 32 percent stated to be satisfied with the actual level of physical activity of their patients. Influencing factors were low patient motivation, high workload causing priority shifts of tasks and the role of physicians.\n\nConclusionAlthough their perceived dominant role in physical activity promotion, nurses identified a number of barriers interfering with actual level of physical activity. Improvement strategies should involve physicians, patients and carers.

scientific communication and education↗