Reuniting the Body "Neck Up and Neck Down" to Understand Cognitive Aging: The Nexus of Geroscience and Neuroscience

Activation of the muscle-to-brain axis ameliorates neurocognitive deficits in an Alzheimer's disease mouse model via enhancing neurotrophic and synaptic signaling

Skeletal muscle regulates central nervous system (CNS) function and health, activating the muscle-to-brain axis through the secretion of skeletal muscle-originating factors ("myokines") with neuroprotective properties. However, the precise mechanisms underlying these benefits in the context of Alzheimer's disease (AD) remain poorly understood. To investigate muscle-to-brain axis signaling in response to amyloid β (Aβ)-induced toxicity, we generated 5xFAD transgenic female mice with enhanced skeletal muscle function (5xFAD;cTFEB;HSACre) at prodromal (4-months old) and late (8-months old) symptomatic stages. Skeletal muscle TFEB overexpression reduced Aβ plaque accumulation in the cortex and hippocampus at both ages and rescued behavioral neurocognitive deficits in 8-month-old 5xFAD mice. These changes were associated with transcriptional and protein remodeling of neurotrophic signaling and synaptic integrity, partially due to the CNS-targeting myokine prosaposin (PSAP). Our findings implicate the muscle-to-brain axis as a novel neuroprotective pathway against amyloid pathogenesis in AD.

Communication Ecology Model of Successful Aging in Indonesian Context

The communication ecology model of successful aging (CEMSA) as a part of aging studies from a communication perspective was replicated in the Indonesian context. The CEMSA provided a specific perspective from communication scholars about the successful aging process. The study of CEMSA has grown significantly to demonstrate the importance of the interactive-communication process to propagate and enhance aging studies. However, there has been no specific aging study from a communication perspective, especially from communication scholars in the Indonesian context. This study applied all concepts, variables, measurements, and analyses from the replicated study. The result showed that seven domains of communication about aging may be relevant to predict successful aging from a negative effect and positive effect, and efficacy toward aging. The model showed that the uncertainty and combination of a negative and positive effect in seven domains of communication about aging could construct the efficacy and success of the aging process. The model with seven domains of communication about aging could be proved while the data were gathered not by self-report.

Comorbidity and Management of Concurrent Psychiatric and Medical Disorders

Aging increases susceptibility to medical and psychiatric comorbidity via interrelated biological, psychological, and social mechanisms. Mental status changes or other psychiatric symptoms occurring in older adults with medical disorders most often result from delirium, depression, or the onset of Alzheimer's disease and related dementias (ADRD). Clinicians can use evidence-based tools to evaluate such symptoms including the 4A's Test for delirium, the Saint Louis University Mental Status Exam, and the Geriatric Depression Scale. Innovative models such as collaborative care can improve the outcome of care of older adults with medical disorders requiring treatment for depression or ADRD..

Biological aging processes underlying cognitive decline and neurodegenerative disease

Alzheimer's disease and related dementias (ADRD) are among the top contributors to disability and mortality in later life. As with many chronic conditions, aging is the single most influential factor in the development of ADRD. Even among older adults who remain free of dementia throughout their lives, cognitive decline and neurodegenerative changes are appreciable with advancing age, suggesting shared pathophysiological mechanisms. In this Review, we provide an overview of changes in cognition, brain morphology, and neuropathological protein accumulation across the lifespan in humans, with complementary and mechanistic evidence from animal models. Next, we highlight selected aging processes that are differentially regulated in neurodegenerative disease, including aberrant autophagy, mitochondrial dysfunction, cellular senescence, epigenetic changes, cerebrovascular dysfunction, inflammation, and lipid dysregulation. We summarize research across clinical and translational studies to link biological aging processes to underlying ADRD pathogenesis. Targeting fundamental processes underlying biological aging may represent a yet relatively unexplored avenue to attenuate both age-related cognitive decline and ADRD. Collaboration across the fields of geroscience and neuroscience, coupled with the development of new translational animal models that more closely align with human disease processes, is necessary to advance novel therapeutic discovery in this realm.

Bridging the Gap: A Geroscience Primer for Neuroscientists With Potential Collaborative Applications

While neurodegenerative diseases can strike at any age, the majority of afflicted individuals are diagnosed at older ages. Due to the important impact of age in disease diagnosis, the field of neuroscience could greatly benefit from the many of the theories and ideas from the biology of aging-now commonly referred as geroscience. As discussed in our complementary perspective on the topic, there is often a "silo-ing" between geroscientists who work on understanding the mechanisms underlying aging and neuroscientists who are studying neurodegenerative diseases. While there have been some strong collaborations between the biology of aging and neuroscientists, there is still great potential for enhanced collaborative effort between the 2 fields. To this end, here, we review the state of the geroscience field, discuss how neuroscience could benefit from thinking from a geroscience perspective, and close with a brief discussion on some of the "missing links" between geroscience and neuroscience and how to remedy them. Notably, we have a corresponding, concurrent review from the neuroscience perspective. Our overall goal is to "bridge the gap" between geroscience and neuroscience such that more efficient, reproducible research with translational potential can be conducted.