Aging is associated with intestinal dysbiosis, a condition characterized by diminished microbial biodiversity and inflammation. This leads to increased vulnerability to extraintestinal manifestations such as autoimmune, metabolic, and neurodegenerative conditions thereby accelerating mortality. As such, modulation of the gut microbiome is a promising way to extend healthspan. In this study, we explore the effects of fecal microbiota transplant (FMT) from long-living Ames dwarf donors to their normal littermates, and vice versa, on the recipient gut microbiota and liver transcriptome. Importantly, our previous studies highlight differences between the microbiome of Ames dwarf mice relative to their normal siblings, potentially contributing to their extended lifespan and remarkable healthspan. Our findings demonstrate that FMT from Ames dwarf mice to normal mice significantly alters the recipient’s gut microbiota, potentially reprogramming bacterial functions related to healthy aging, and changes the liver transcriptome, indicating improved metabolic health. Particularly, the microbiome of Ames dwarf mice, characterized by a higher abundance of beneficial bacterial families such as Peptococcaceae, Oscillospiraceae, and Lachnospiraceae, appears to play a crucial role in modulating these effects. Alongside, our mRNA sequencing and RT-PCR validation reveals that FMT may contribute to the significant downregulation of p21, Elovl3, and Insig2, genes involved with cellular senescence and liver metabolic pathways. Our data suggest a regulatory axis exists between the gut and liver, highlighting the potential of microbiome-targeted therapies in promoting healthy aging. Future research should focus on functional validation of altered microbial communities and explore the underlying biomolecular pathways that confer geroprotection.
Alzheimer's Disease and Alzheimer's Disease-related dementias (AD/ADRD) pose major global healthcare challenges, with diabetes mellitus (DM) being a key risk factor. Both AD and DM-related ADRD are characterized by reduced cerebral blood flow, although the exact mechanisms remain unclear. We previously identified compromised cerebral hemodynamics as early signs in TgF344-AD and type 2 DM-ADRD (T2DN) rat models. Genome-wide studies have linked AD/ADRD to SNPs in soluble epoxide hydrolase (sEH). This study explored the effects of sEH inhibition with TPPU on cerebral vascular function and cognition in AD and DM-ADRD models. Chronic TPPU treatment improved cognition in both AD and DM-ADRD rats without affecting body weight. In DM-ADRD rats, TPPU reduced plasma glucose and HbA1c levels. Transcriptomic analysis of primary cerebral vascular smooth muscle cells from AD rats treated with TPPU revealed enhanced pathways related to cell contraction, alongside decreased oxidative stress and inflammation. Both AD and DM-ADRD rats exhibited impaired myogenic responses and autoregulation in the cerebral circulation, which were normalized with chronic sEH inhibition. Additionally, TPPU improved acetylcholine-induced vasodilation in the middle cerebral arteries (MCA) of DM-ADRD rats. Acute TPPU administration unexpectedly caused vasoconstriction in the MCA of DM-ADRD rats at lower doses. In contrast, higher doses or longer durations were required to induce effective vasodilation at physiological perfusion pressure in both control and ADRD rats. Additionally, TPPU decreased reactive oxygen species production in cerebral vessels of AD and DM-ADRD rats. These findings provide novel evidence that chronic sEH inhibition can reverse cerebrovascular dysfunction and cognitive impairments in AD/ADRD, offering a promising avenue for therapeutic development.
Ageing individuals often experience cognitive decline and intrinsic functional connectivity (FC) changes. Psychological resilience, a personality trait that reflects the capacity to adapt and cope with age-related challenges, plays a key role in mitigating cognitive decline. In this study involving 101 older adults, we investigated how psychological resilience influences cognitive decline measured by processing speed. Particularly, we obtained resting-state functional magnetic resonance imaging (fMRI) to assess how intrinsic FC, represented by degree centrality, modulates the relationship between resilience and processing speed. Our results indicated while psychological resilience positively predicted processing speed, this relationship was mainly driven by education. Additionally, the degree centrality of both thalamus and caudate negatively correlated with processing speed and resilience. Notably, the degree centrality of both thalamus and caudate significantly mediated the relationship between resilience and processing speed. These findings suggest that psychological resilience could protect against age-related cognitive decline via its influence on FC in the thalamus and caudate, highlighting these areas as potential intervention targets for reducing cognitive decline in ageing people.
This randomized controlled trial compared the effects of home-based exercise, with or without cognitive training, on cognition and physical function in individuals aged 50 years and older with stable CVD during the COVID-19 pandemic. 122 patients (67.3 ± 7.9 years, 71% men) with stable CVD (77% coronary heart disease) were randomly assigned (1:1) to (1) Home-based physical exercise alone, or (2) Home-based physical exercise combined with cognitive training. Cognition (executive functions (primary outcome), processing speed, episodic memory, and working memory) and physical functions were assessed remotely at baseline, 3 months, and 6 months. Adjusted mean changes from baseline to 3 months and 6 months for executive functions, episodic memory, working memory, sit-to-stand test, gait speed, and timed up-and-go test were significant in the overall sample (p < 0.05). Furthermore, executive functions, episodic memory, sit-to-stand test, and timed up-and-go performances were significantly improved at 6 months in both groups when analyzed separately although no group differences were observed. Mean exercise dose differed significantly between the 2 groups: 1413 vs 953 METs.min−1 week−1 respectively for the exercise and combined group (p < 0.01). Mean cognitive training duration was 25.6 ± 16.6 min.week−1 for the combined intervention group. Results remained unchanged after accounting for the exercise dose. In adults affected by CVD, a remote combined intervention integrating sequential cognitive and exercise training yields comparable enhancements in executive function, episodic memory, and physical performances compared to exercise training alone. ClinicalTrials.gov: NCT04661189.