The association between aging-related monocyte transcriptional networks and comorbidity burden: the Multi-Ethnic Study of Atherosclerosis (MESA)

Triglyceride-glucose index is independently associated with fatty pancreas disease in Chinese elderly

OBJECTIVE

To determine the prevalence of fatty pancreas disease (FPD) diagnosed by transabdominal ultrasound in Chinese elderly aged 65 years and above to explore the correlation between triglyceride glucose index (TyG index) and FPD and its severity, and to evaluate the ability of TyG index to identify FPD and its severity.

METHODS

The study population was derived from the Thyroid Diseases in Older Population: Screening, Surveillance, and Intervention (TOPS) study conducted in the iodine-adapted areas of Jiangsu Province from May to July 2021. A total of 567 participants aged 65 years and above in rural areas were included in the final analysis. TyG index was calculated by the established formula: Ln [TG (mg/dL) × FBG (mg/dL)/2]. FPD and the degree of intra-pancreatic fat deposition (IPFD) were diagnosed by abdominal ultrasound. The logistic regression model was performed to determine the correlation between clinical parameters, including TyG index, and FPD and its severity. The diagnostic power of TyG index was assessed by receiver operating characteristic curve (ROC).

RESULTS

Overall, 72.66% (412/567) of subjects had FPD, of which over half had moderate to severe FPD. The proportions of overweight, obesity, NAFLD, and dyslipidemia were significantly higher in the moderate-to-severe FPD group than in the mild FPD group. Multivariate logistic regression showed that TyG index was independently associated with FPD in the elderly population, but was not significantly associated with the severity of IPFD. As the level of TyG index increased, the metabolic disorders in the population worsened and the prevalence of FPD increased significantly. TyG index had a good diagnostic performance for FPD. The combination of BMI or NAFLD and TyG index improved the diagnostic ability for FPD.

CONCLUSION

The prevalence of FPD diagnosed by abdominal ultrasound is high in the elderly aged 65 years and above in rural areas in China. TyG index has good identification of FPD but poor recognition of the severity of IPFD. TyG index, when combined with other clinical parameters, may have more diagnostic advantages.

Plasma and neuroimaging biomarkers of small vessel disease and Alzheimer's disease in a diverse cohort: MESA

INTRODUCTION

Little is known about how Alzheimer's disease (AD) plasma biomarkers relate to cerebral small vessel disease (cSVD) neuroimaging biomarkers.

METHODS

The study involved 251 Wake Forest Multi-Ethnic Study of Atherosclerosis (MESA) Exam 6 participants with plasma AD biomarkers, MRI, amyloid PET, and adjudicated cognitive status. Multivariable models examined cross-sectional relationships between plasma and neuroimaging biomarkers, considering comorbidities.

RESULTS

Lower Aβ42/Aβ40, and higher GFAP, NfL, and p-tau217 were associated with greater neurodegeneration. Lower plasma Aβ42/Aβ40 and higher p-tau217 and p-tau231 were associated with greater Aβ PET deposition. NfL was positively associated with WMH and WM Free Water. P-tau measures were positively associated with WM Free Water. Lower Aβ42/Aβ40 was associated with presence of microbleeds. GFAP was positively associated with WMH.

DISCUSSION

We observed expected associations of plasma biomarkers with cognitive status and imaging biomarkers. GFAP, NfL, p-tau181, p-tau217, and p-tau231 are associated with cSVD in addition to AD-related pathology.

Gadd45A-mediated autophagy regulation and its impact on Alzheimer's disease pathogenesis: Deciphering the molecular Nexus

BACKGROUND

The growth arrest and DNA damage-inducible 45 (Gadd45) gene has been implicated in various central nervous system (CNS) functions, both normal and pathological, including aging, memory, and neurodegenerative diseases. In this study, we examined whether Gadd45A deletion triggers pathways associated with neurodegenerative diseases including Alzheimer's disease (AD).

METHODS

Utilizing transcriptome data from AD-associated hippocampus samples, we identified Gadd45A as a pivotal regulator of autophagy. Comprehensive analyses, including Gene Ontology enrichment and protein-protein interaction network assessments, highlighted Cdkn1A as a significant downstream target of Gadd45A. Experimental validation confirmed Gadd45A's role in modulating Cdkn1A expression and autophagy levels in hippocampal cells. We also examined the effects of autophagy on hippocampal functions and proinflammatory cytokine secretion. Additionally, a murine model was employed to validate the importance of Gadd45A in neuroinflammation and AD pathology.

RESULTS

Our study identified 20 autophagy regulatory factors associated with AD, with Gadd45A emerging as a critical regulator. Experimental findings demonstrated that Gadd45A influences hippocampal cell fate by reducing Cdkn1A expression and suppressing autophagic activity. Comparisons between wild-type (WT) and Gadd45A knockout (Gadd45A-/-) mice revealed that Gadd45A-/- mice exhibited significant cognitive impairments, including deficits in working and spatial memory, increased Tau hyperphosphorylation, and elevated levels of kinases involved in Tau phosphorylation in the hippocampus. Additionally, Gadd45A-/- mice showed significant increases in pro-inflammatory cytokines and decreases autophagy markers in the brain. Neurotrophin levels and dendritic spine length were also reduced in Gadd45A-/- mice, likely contributing to the observed cognitive deficits.

CONCLUSIONS

These findings support the direct involvement of the Gadd45A gene in AD pathogenesis, and enhancing the expression of Gadd45A may represent a promising therapeutic strategy for the treatment of AD.

Muscle Mitochondrial Bioenergetic Capacities Are Associated With Multimorbidity Burden in Older Adults: The Study of Muscle, Mobility and Aging

BACKGROUND

The geroscience hypothesis posits that aging biological processes contribute to many age-related deficits, including the accumulation of multiple chronic diseases. Though only one facet of mitochondrial function, declines in muscle mitochondrial bioenergetic capacities may contribute to this increased susceptibility to multimorbidity.

METHODS

The Study of Muscle, Mobility and Aging (SOMMA) assessed ex vivo muscle mitochondrial energetics in 764 older adults (mean age = 76.4, 56.5% women, and 85.9% non-Hispanic White) by high-resolution respirometry of permeabilized muscle fibers. We estimated the proportional odds ratio (POR [95% CI]) for the likelihood of greater multimorbidity (4 levels: 0 conditions, N = 332; 1 condition, N = 299; 2 conditions, N = 98; or 3+ conditions, N = 35) from an index of 11 conditions, per SD decrement in muscle mitochondrial energetic parameters. Distribution of conditions allowed for testing the associations of maximal muscle energetics with some individual conditions.

RESULTS

Lower oxidative phosphorylation supported by fatty acids and/or complex I- and II-linked carbohydrates (eg, Max OXPHOSCI+CII) was associated with a greater multimorbidity index score (POR = 1.32 [1.13, 1.54]) and separately with diabetes mellitus (OR = 1.62 [1.26, 2.09]), depressive symptoms (OR = 1.45 [1.04, 2.00]) and possibly chronic kidney disease (OR = 1.57 [0.98, 2.52]) but not significantly with other conditions (eg, cardiac arrhythmia, chronic obstructive pulmonary disease).

CONCLUSIONS

Lower muscle mitochondrial bioenergetic capacities were associated with a worse composite multimorbidity index score. Our results suggest that decrements in muscle mitochondrial energetics may contribute to a greater global burden of disease and are more strongly related to some conditions than others.

Muscle mitochondrial bioenergetic capacities is associated with multimorbidity burden in older adults: the Study of Muscle, Mobility and Aging (SOMMA)

Background

The geroscience hypothesis posits that aging biological processes contribute to many age-related deficits, including the accumulation of multiple chronic diseases. Though only one facet of mitochondrial function, declines in muscle mitochondrial bioenergetic capacities may contribute to this increased susceptibility to multimorbidity.

Methods

The Study of Muscle, Mobility and Aging (SOMMA) assessed ex vivo muscle mitochondrial energetics in 764 older adults (mean age =76.4, 56.5% women, 85.9% non-Hispanic white) by high-resolution respirometry of permeabilized muscle fibers. We estimated the proportional odds ratio (POR [95%CI]) for the likelihood of greater multimorbidity (four levels: 0 conditions, N=332; 1 condition, N=299; 2 conditions, N=98; or 3+ conditions, N=35) from an index of 11 conditions, per SD decrement in muscle mitochondrial energetic parameters. Distribution of conditions allowed for testing the associations of maximal muscle energetics with some individual conditions.

Results

Lower oxidative phosphorylation supported by fatty acids and/or complex-I and -II linked carbohydrates (e.g., Max OXPHOSCI+CII) was associated with a greater multimorbidity index score (POR=1.32[1.13,1.54]) and separately with diabetes mellitus (OR=1.62[1.26,2.09]), depressive symptoms (OR=1.45[1.04,2.00]) and possibly chronic kidney disease (OR=1.57[0.98,2.52]) but not significantly with other conditions (e.g., cardiac arrhythmia, chronic obstructive pulmonary disease).

Conclusions

Lower muscle mitochondrial bioenergetic capacities was associated with a worse composite multimorbidity index score. Our results suggest that decrements in muscle mitochondrial energetics may contribute to a greater global burden of disease and is more strongly related to some conditions than others.

Molecular bases of comorbidities: present and future perspectives

Co-occurrence of diseases decreases patient quality of life, complicates treatment choices, and increases mortality. Analyses of electronic health records present a complex scenario of comorbidity relationships that vary by age, sex, and cohort under study. The study of similarities between diseases using 'omics data, such as genes altered in diseases, gene expression, proteome, and microbiome, are fundamental to uncovering the origin of, and potential treatment for, comorbidities. Recent studies have produced a first generation of genetic interpretations for as much as 46% of the comorbidities described in large cohorts. Integrating different sources of molecular information and using artificial intelligence (AI) methods are promising approaches for the study of comorbidities. They may help to improve the treatment of comorbidities, including the potential repositioning of drugs.

Aging and aging-related diseases: from molecular mechanisms to interventions and treatments

Aging is a gradual and irreversible pathophysiological process. It presents with declines in tissue and cell functions and significant increases in the risks of various aging-related diseases, including neurodegenerative diseases, cardiovascular diseases, metabolic diseases, musculoskeletal diseases, and immune system diseases. Although the development of modern medicine has promoted human health and greatly extended life expectancy, with the aging of society, a variety of chronic diseases have gradually become the most important causes of disability and death in elderly individuals. Current research on aging focuses on elucidating how various endogenous and exogenous stresses (such as genomic instability, telomere dysfunction, epigenetic alterations, loss of proteostasis, compromise of autophagy, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, deregulated nutrient sensing) participate in the regulation of aging. Furthermore, thorough research on the pathogenesis of aging to identify interventions that promote health and longevity (such as caloric restriction, microbiota transplantation, and nutritional intervention) and clinical treatment methods for aging-related diseases (depletion of senescent cells, stem cell therapy, antioxidative and anti-inflammatory treatments, and hormone replacement therapy) could decrease the incidence and development of aging-related diseases and in turn promote healthy aging and longevity.