Relationship between hemoglobin and specific cognitive domain among older adults using network analysis.

OBJECTIVES: Hemoglobin (Hgb) is associated with cognitive function, with low and high levels of Hgb leading to impaired cerebral oxygenation and perfusion. Yet, current studies focused on understanding the association between Hgb and cognitive function without consideration for each cognitive domain. Thus, this study aims to identify and visualize potentially interactive associations between Hgb and specific cognitive domains among older adults. METHOD: This is a secondary data analysis using Wave II data from the National Social Life, Health, and Aging Project (NSHAP) and included 1022 older adults aged between 65 and 85 years. The network structure of three different models was estimated to understand the association between specific cognitive domains and Hgb in a mixed graphical model using the R-package 'mgm'. Model 1 did not adjust for any covariates, Model 2 adjusted for age and gender, and Model 3 adjusted for all covariates. RESULTS: Among all cognitive domains, the visuospatial (edge weight = 0.06-0.10) and memory domains (0.04-0.07) were associated with Hgb in all three models Though not present in Model 3, the attention domain was associated with Hgb in Model 1 and Model 2 (0.08-0.11). In addition, the predictability of Hgb was the highest (8.1%) in Model 3. CONCLUSION: Findings from this study suggest that cognition should be considered as a multidimensional construct, and its specific cognitive domain should be carefully assessed and managed in relation to Hgb among older adults.

Changes in Symptom Clusters Among Asian American Breast Cancer Survivors in Technology-Based Coaching Intervention.

BACKGROUND: Limited research studies have focused on examining the impact of technology-based interventions in changing symptom clusters among Asian American breast cancer survivors. OBJECTIVE: The aim of this study was to understand the longitudinal impact of a technology-based program on the symptom cluster experience of Asian American breast cancer survivors. METHODS: This is a secondary data analysis that used exploratory factor analysis at each time point (baseline, post-1 month, post-3 months) for the control and intervention groups (N = 199). RESULTS: The number of symptom clusters remained the same, and the same symptoms remained in similar clusters across the 2 groups. The control group experienced psychological cluster, fatigue cluster, and neck/skin cluster at baseline; psychological cluster, fatigue/dizzy cluster, and neck/skin cluster at post-1 month; and psychological cluster, fatigue/dizzy cluster, and somatic cluster at post-3 months. The intervention group experienced psychological cluster, neck cluster, and appetite/itching cluster at baseline; somatic/anticholinergic cluster, psychological/sexual cluster, and appetite cluster at post-1 month; and psychological cluster, neck cluster, and itching cluster at post-3 months. The psychological and neck clusters shared similar core symptoms of feeling nervous, dry mouth, and cough between the control and intervention groups. CONCLUSION: The different symptom cluster experiences may be due to the technology-based intervention where the intervention group receives individual/group coaching/support that may have changed symptom clusters over time. Yet, the true efficacy of the intervention on symptom clusters warrants further investigation. IMPLICATIONS FOR PRACTICE: Clinicians should understand the changes in symptom clusters as well as the presence of core symptoms and take a targeted symptom cluster approach in clinical settings.

An Examination of the Non-linear Relationship Between Cognition and Total Hemoglobin Among the Cognitively Normal Older Adults by Gender.

Objectives: This exploratory study aimed to identify the potential non-linear relationship between hemoglobin (Hgb) and cognition among cognitively normal older adults and how this relationship differs in terms of gender in generalized additive models (GAM). Methods: This is a secondary data analysis using Wave II (2010-2011) data from the National Social Life, Health, and Aging Project. A generalized additive model was used to understand the non-linear relationship between Hgb and cognition, and to identify critical Hgb point related to cognition. Results: While both genders had a non-linear association between Hgb and cognition, the degree of non-linearity was more pronounced in male older adults with EDF value close to 2. The inflection point of 15.10 g/dL for male older adults and inflection point of 11.72 g/dL for female older adults were obtained. Conclusion: Further studies are needed to validate these results and develop precision medicine approaches to integrate these results into clinical practice.

Transitions in Social Networks From Young-Old to Old-Old Stage of Life Using Latent Transition Analysis.

Introduction: This study aimed to identify the different types of social networks among young-old adults, and to examine the transitions in social networks as they become old-old adults. Methods: This is a secondary data analysis using the longitudinal data (N = 1092) from the National Social Life, Health, and Aging Project. Latent class analysis was conducted to identify optimal number of classes and latent transition analysis was conducted to examine the transition probabilities. Results: Young-old adults in Class 1: family-oriented, social (close, external) transitioned into Class 2: family-oriented, non-social over time. In contrast, young-old adults in Class 2: family-oriented, non-social and Class 3: less family-oriented, social (close) were less likely to transition to another class. Conclusion: Older adults engaged in less social activities over time. Older adults should be encouraged to continue their social engagement with close social network of friends and relatives, and to maintain their relationship with family members.

Beneficial Effects of Low-Grade Mitochondrial Stress on Metabolic Diseases and Aging.

Mitochondria function as platforms for bioenergetics, nutrient metabolism, intracellular signaling, innate immunity regulators, and modulators of stem cell activity. Thus, the decline in mitochondrial functions causes or correlates with diabetes mellitus and many aging-related diseases. Upon stress or damage, the mitochondria elicit a series of adaptive responses to overcome stress and restore their structural integrity and functional homeostasis. These adaptive responses to low-level or transient mitochondrial stress promote health and resilience to upcoming stress. Beneficial effects of low-grade mitochondrial stress, termed mitohormesis, have been observed in various organisms, including mammals. Accumulated evidence indicates that treatments boosting mitohormesis have therapeutic potential in various human diseases accompanied by mitochondrial stress. Here, we review multiple cellular signaling pathways and interorgan communication mechanisms through which mitochondrial stress leads to advantageous outcomes. We also discuss the relevance of mitohormesis in obesity, diabetes, metabolic liver disease, aging, and exercise.

Hypothalamic AMP-Activated Protein Kinase as a Whole-Body Energy Sensor and Regulator.

5´-Adenosine monophosphate (AMP)-activated protein kinase (AMPK), a cellular energy sensor, is an essential enzyme that helps cells maintain stable energy levels during metabolic stress. The hypothalamus is pivotal in regulating energy balance within the body. Certain neurons in the hypothalamus are sensitive to fluctuations in food availability and energy stores, triggering adaptive responses to preserve systemic energy equilibrium. AMPK, expressed in these hypothalamic neurons, is instrumental in these regulatory processes. Hypothalamic AMPK activity is modulated by key metabolic hormones. Anorexigenic hormones, including leptin, insulin, and glucagon-like peptide 1, suppress hypothalamic AMPK activity, whereas the hunger hormone ghrelin activates it. These hormonal influences on hypothalamic AMPK activity are central to their roles in controlling food consumption and energy expenditure. Additionally, hypothalamic AMPK activity responds to variations in glucose concentrations. It becomes active during hypoglycemia but is deactivated when glucose is introduced directly into the hypothalamus. These shifts in AMPK activity within hypothalamic neurons are critical for maintaining glucose balance. Considering the vital function of hypothalamic AMPK in the regulation of overall energy and glucose balance, developing chemical agents that target the hypothalamus to modulate AMPK activity presents a promising therapeutic approach for metabolic conditions such as obesity and type 2 diabetes mellitus.

Hypothalamic astrocyte NAD+ salvage pathway mediates the coupling of dietary fat overconsumption in a mouse model of obesity.

Nicotinamide adenine dinucleotide (NAD)+ serves as a crucial coenzyme in numerous essential biological reactions, and its cellular availability relies on the activity of the nicotinamide phosphoribosyltransferase (NAMPT)-catalyzed salvage pathway. Here we show that treatment with saturated fatty acids activates the NAD+ salvage pathway in hypothalamic astrocytes. Furthermore, inhibition of this pathway mitigates hypothalamic inflammation and attenuates the development of obesity in male mice fed a high-fat diet (HFD). Mechanistically, CD38 functions downstream of the NAD+ salvage pathway in hypothalamic astrocytes burdened with excess fat. The activation of the astrocytic NAMPT-NAD+-CD38 axis in response to fat overload induces proinflammatory responses in the hypothalamus. It also leads to aberrantly activated basal Ca2+ signals and compromised Ca2+ responses to metabolic hormones such as insulin, leptin, and glucagon-like peptide 1, ultimately resulting in dysfunctional hypothalamic astrocytes. Our findings highlight the significant contribution of the hypothalamic astrocytic NAD+ salvage pathway, along with its downstream CD38, to HFD-induced obesity.