The critical role of metabolic pathways in aging

A novel sex-specific association between insulin resistance and depressive symptoms in older adults: The potential mediating role of Vascular Endothelial Growth Factor

BACKGROUND

Insulin resistance (IR) and depression are increasingly recognized as interconnected conditions in aging, potentially linked through chronic low-grade inflammation ("inflammaging"). The triglyceride-glucose (TyG) index has emerged as a validated surrogate marker of IR, yet its relationship with inflammatory biomarkers and depressive symptoms in older adults remains underexplored.

OBJECTIVE

This study investigated the association between the TyG index, depressive symptoms, and circulating inflammatory molecules in cognitively healthy older adults, with emphasis on sex-specific differences and the potential mediating role of vascular endothelial growth factor (VEGF).

METHODS

In this retrospective study, 118 non-diabetic older adults (mean age 74.1 years; 52.5 % men) with preserved cognition (MMSE ≥27) were assessed. Depressive symptoms were measured using the Geriatric Depression Scale (GDS), while cytokines and growth factors were quantified via multiplex immunoassay. The TyG index was calculated from fasting glucose and triglyceride levels. Multiple linear regression models controlled for age, sex, BMI, and medication use.

RESULTS

Depressive symptoms (GDS ≥5) were present in 31.35 % of participants. Those with depression had lower levels of anti-inflammatory cytokines and elevated levels of VEGF and MCP-1. TyG index correlated with both GDS scores (r = 0.239, p = 0.017) and VEGF (r = 0.271, p = 0.005), with significant associations observed only in women. VEGF emerged as a key mediator in the TyG-depression link in women (R2 = 0.425).

CONCLUSIONS

These findings suggest a sex-specific metabolic-inflammatory signature in late-life depression. VEGF may serve as a mechanistic link between IR and depressive symptoms in older women, supporting sex-tailored interventions.

Deciphering the association of cholesteryl ester transfer protein (CETP) gene polymorphisms with high-density lipoprotein cholesterol (HDL-c) levels in the Bangladeshi population

Cholesteryl ester transfer protein (CETP) gene polymorphisms influence CETP expression and high-density lipoprotein cholesterol (HDL-c) levels, yet their genetic impact remains unexplored in the Bangladeshi population, where low HDL-c is prevalent. This study examined the association of CETP -629C/A and 277C/T polymorphisms with circulating HDL-c levels in 402 individuals (217 males, 185 females). Serum lipid profiles were measured using an automated analyzer, and CETP polymorphisms were genotyped using PCR-RFLP. The -629C/A and 277C/T polymorphisms were in Hardy-Weinberg equilibrium, with heterozygous genotypes being the most frequent. While -629C/A genotypes showed no significant difference between the high and low HDL-c groups, individuals carrying the -629AA and CA + AA genotypes had significantly higher HDL-c levels compared to CC carriers (p = 0.023, p = 0.043). For the 277C/T, TT genotype differed significantly between the high and low HDL-c groups (p = 0.011, OR = 0.37) and, individuals carrying the 277 TT and CT + TT genotypes had significantly higher HDL-c compared to the CC genotype (p = 0.002, p = 0.019). Additionally, allelic analysis suggested a marginal association between the 277T allele and increased HDL-c levels (p = 0.051, OR = 0.59). Multiple regression analysis confirmed an inverse association between -629CC (β = -1.106, p = 0.038) and 277CC + CT (β = -0.963, p = 0.016) with HDL-c levels. However, no significant differences were observed in total cholesterol, triglycerides, LDL-c, or apolipoprotein levels across genotypes. These findings suggest that CETP -629CC, 277CC, and CT genotypes contribute to low HDL-c levels in the Bangladeshi population, highlighting the potential role of CETP genetic screening as a biomarker for identifying individuals at risk of HDL-c deficiency and associated cardiovascular complications.

Investigating the obesity trend of overweight and obese people with pictograms among Iranian adults

Purpose

Obesity is a major public health concern, particularly in resource-constrained areas where measuring it accurately is challenging due to insufficient equipment and trained personnel. In Iran, there is a notable lack of comprehensive longitudinal studies using modern tools to track adult obesity trends. This study employed body shape pictograms (BIP) to classify abdominal obesity and aimed to reveal trends in perceived obesity among Iranian adults.

Methods

This cross-sectional study involved individuals from the multidisciplinary obesity registry at Shariati Hospital, from 2013 to February 2021. It included patients aged 30 to 65 with morbid obesity (BMI ≥ 35) who were potential bariatric surgery candidates. Medical history, anthropometric data, laboratory data, and the obesity pictogram were collected through face-to-face private interviews.

Results

We recruited 346 participants (287 females and 59 males). The study found an upward trend in obesity, indicated by pictogram scores across all categories (p <.001). Mean pictogram scores significantly varied by obesity levels based on BMI (p <.001) and were positively associated with waist and hip circumference (p <.001). No significant associations were found with diabetes or metabolic syndrome status.

Conclusion

This study underscores the significant trend of perceived obesity among Iranian adults, as assessed through pictograms. Accurate data on obesity trends among overweight and obese individuals over time can play a crucial role in shaping the country's health policies to combat obesity.

Clinical trial number

Not applicable.

Nonessential amino acid is not nonessential in geriatric patients: implications for maxillofacial wound healing and bone repair

BACKGROUND

Nonessential amino acids (NEAAs) are traditionally regarded as dispensable because they can be synthesized endogenously from glucose-derived intermediates. Emerging evidence, however, shows that the capacity for de novo NEAA biosynthesis declines in aged tissues, rendering several of these molecules conditionally essential during periods of stress such as surgery or fracture repair.

MAIN BODY

In the cranio-maxillofacial arena - where bone and soft-tissue regeneration must occur in an environment already compromised by osteoporosis, multimorbidity, and restricted oral intake - insufficient NEAA supply may translate into delayed union, wound dehiscence, and heightened infection risk. This narrative review integrates biochemical, preclinical, and clinical data to map age-dependent changes in the serine/glycine, glutamine/glutamate, arginine/citrulline, cysteine/trans-sulfuration, and alanine cycles, examines their impact on osteogenesis and mucosal healing, and evaluates nutritional or pharmacological strategies to restore NEAA sufficiency. Particular attention is paid to serine-one-carbon metabolism, the intestinal-renal arginine axis, and redox-sensitive cysteine pathways, all of which are intimately linked to collagen deposition, osteoblast differentiation, and immune modulation.

CONCLUSION

We conclude that proactive optimization of NEAA status - through targeted supplementation or metabolic activation - represents a low-risk, biologically rational adjunct to enhance postoperative outcomes in geriatric maxillofacial patients.

Analysis and study of risk factors related to the progression of non-alcoholic fatty liver disease: A retrospective cohort study

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is becoming increasingly prevalent worldwide. This study aimed to analyze the risk factors associated with NAFLD progression by collecting and evaluating clinical data of NAFLD patients, providing a scientific basis for its prevention and treatment.

METHODS

Clinical data of NAFLD patients from June 2015 to June 2016 were retrospectively collected, including gender, age, alanine aminotransferase (ALT), aspartate aminotransferase(AST), alkaline phosphatase(ALP),γ-glutamyltranspeptidase (GGT), triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), fasting blood glucose (FBG), and visceral fat area (VFA). All patients were stratified by gender and age, and logistic regression analysis was used to explore the risk factors for NAFLD disease progression.

RESULTS

ALT, TG, FBG, and VFA were identified as independent risk factors for NAFLD progression. Stratified analysis showed that in male patients, ALT, TG, and VFA were independent risk factors, whereas in female patients, TG, FBG, and VFA were identified as independent risk factors. Age-stratified analysis revealed that ALT, TG, and VFA were significant risk factors for progression in young and middle-aged patients. At the same time, age, ALT, TG, and FBG were substantial in elderly patients.

CONCLUSION

Different risk factors should be closely monitored in sex- and age-specific populations to prevent NAFLD progression effectively.

Metabolaging: a new geroscience perspective linking aging pathologies and metabolic dysfunction

With age, our metabolic systems undergo significant alterations, which can lead to a cascade of adverse effects that are implicated in both metabolic disorders, such as diabetes, and in the body's ability to respond to acute stress and trauma. To elucidate the metabolic imbalances arising from aging, we introduce the concept of "metabolaging." This framework encompasses the broad spectrum of metabolic disruptions associated with the hallmarks of aging, including the functional decline of key metabolically active organs, like the adipose tissue. By examining how these organs interact with essential nutrient-sensing pathways, "metabolaging" provides a more comprehensive view of the systemic metabolic imbalances that occur with age. This concept extends to understanding how age-related metabolic disturbances can influence the response to acute stressors, like burn injuries, highlighting the interplay between metabolic dysfunction and the ability to handle severe physiological challenges. Finally, we propose potential interventions that hold promise in mitigating the effects of metabolaging and its downstream consequences.

Social disadvantage accelerates aging

Social disadvantage, like advanced age, is a risk factor for a broad range of health conditions; however, whether it influences the aging process remains unclear. Here, using a multicohort approach, we investigated the associations of social disadvantage with age-related plasma proteins and age-related diseases. We found proteomic signatures of accelerated immune aging and 14 specific age-related proteins linked to social disadvantage during both early and later life. Individuals experiencing social disadvantage had an increased risk of 66 age-related diseases, with up to 39% of these associations mediated by the 14 age-related proteins (for example, DNAJB9, F2, HSPA1A, BGN). The main enriched pathway involved the upregulation of the pro-inflammatory regulator NF-κB24 and its downstream factor interleukin-8. Our findings support the hypothesis that social disadvantage throughout the life course may accelerate aging, a biological mechanism that could explain why social stratification plays such a fundamental role in determining human health.

Survival Tree Analysis of Interactions Among Factors Associated With Colorectal Cancer Risk in Patients With Type 2 Diabetes: Retrospective Cohort Study

Background

Colorectal cancer (CRC) and diabetes share many common lifestyle risk factors, such as obesity. However, it remains largely unknown how different factors interact to influence the risk of CRC development among patients with diabetes.

Objective

This study aimed to identify the interaction patterns among factors associated with the risk of CRC incidence among patients with diabetes.

Methods

This is a retrospective cohort study conducted using electronic health records from Hong Kong. Patients who were diagnosed with type 2 diabetes and received care in general outpatient clinics between 2010 and 2019 without cancer history were included and followed up until December 2019. A conditional inference survival tree was applied to examine the interaction patterns among factors associated with the risk of CRC.

Results

A total of 386,325 patients were included. During a median follow-up of 6.2 years (IQR 3.3-8.0), 4199 patients developed CRC. Patients were first partitioned into 4 age groups by increased levels of CRC risk (≤54 vs 55 to 61 vs 62 to 73 vs >73 years). Among patients aged more than 54 years, male sex was the dominant risk factor for CRC within each age stratum and the associations lessened with age. Abdominal obesity (waist-to-hip ratio >0.95) and longer duration of diabetes (median 12, IQR 7-18 vs median 4, IQR 1-11 years) were identified as key risk factor for CRC among men aged between 62 and 73 years and women aged more than 73 years, respectively.

Conclusions

This study suggests the interaction patterns among age, sex, waist-to-hip ratio, and duration of diabetes on the risk of CRC incidence among patients with diabetes. Findings of the study may help identify target groups for public health intervention strategies.

Senotherapeutic repurposing of metformin for age-related diseases and their signaling pathways

Drug repurposing is the process of using currently approved drugs for a novel treatment or medical condition for which it was not previously indicated. Despite promising preclinical and clinical results, most of the newly designed senotherapeutic agents synthesized have limited clinical utility due to individual and organ-specific variations in aging phenotype and adverse side effects. All these limitations indicate that further clinical research is required to determine the effectiveness of repurposed senotherapeutic drug interventions, such as metformin, for age-related diseases. Metformin exerts diverse senotherapeutic effects on various aging tissues at different metabolic conditions. Although not exhibiting senolytic properties, metformin has effectively suppressed cellular senescence and senescence-associated secretory phenotype (SASP) in age-related diseases (ARDs). Targeting specific SASP-related signaling pathways with metformin may offer new therapeutic benefits to alleviate the detrimental effects of senescent cells accumulated in most common ARDs in the elderly. Metformin was also the first drug evaluated for its senescence-targeting effects in a large clinical trial named "Targeting Aging with Metformin (TAME)". In this review, we critically evaluate the literature to highlight senotherapeutic mechanisms in which metformin can be therapeutically repurposed for the prevention and treatment of ARDs.

Relationship between physical activity and DNA methylation-predicted epigenetic clocks

This study investigates the relationship between physical activity (PA) levels and DNA methylation (DNAm)-predicted epigenetic clocks in a U.S. population sample (n = 948, mean age 62, 49% female). Eight epigenetic clocks were analyzed, revealing that higher PA levels were significantly associated with younger biological ages across all indicators, with the strongest effects observed for SkinBloodAge and LinAge. Multivariable linear regression models, adjusted for sociodemographic and lifestyle factors, highlighted the potential of PA to reduce biological ageing. Subgroup analyses indicated that these associations were more pronounced among non-Hispanic whites, individuals with a BMI of 25-30, and former smokers, suggesting that the impact of PA varies across different groups. These findings emphasize the role of PA in slowing biological ageing and reducing age-related health risks. Promoting regular PA, especially among older adults and those with higher BMI, could improve well-being and lifespan, highlighting PA as a modifiable factor in healthy ageing and age-related disease prevention.

Data-driven cluster analysis of lipids, inflammation, and aging in relation to new-onset type 2 diabetes mellitus

PURPOSE

Early detection and intervention are vital for managing type 2 diabetes mellitus (T2DM) effectively. However, it's still unclear which risk factors for T2DM onset are most significant. This study aimed to use cluster analysis to categorize individuals based on six known risk factors, helping to identify high-risk groups requiring early intervention to prevent T2DM onset.

METHODS

This study comprised 7402 Korean Genome and Epidemiology Study individuals aged 40 to 69 years. The hybrid hierarchical k-means clustering algorithm was employed on six variables normalized by Z-score-age, triglycerides, total cholesterol, non-high-density lipoprotein cholesterol, high-density lipoprotein cholesterol and C-reactive protein. Multivariable Cox proportional hazard regression analyses were conducted to assess T2DM incidence.

RESULTS

Four distinct clusters with significantly different characteristics and varying risks of new-onset T2DM were identified. Cluster 4 (insulin resistance) had the highest T2DM incidence, followed by Cluster 3 (inflammation and aging). Clusters 3 and 4 exhibited significantly higher T2DM incidence rates compared to Clusters 1 (healthy metabolism) and 2 (young age), even after adjusting for covariates. However, no significant difference was found between Clusters 3 and 4 after covariate adjustment.

CONCLUSION

Clusters 3 and 4 showed notably higher T2DM incidence rates, emphasizing the distinct risks associated with insulin resistance and inflammation-aging clusters.

Time restricted feeding with or without ketosis influences metabolism-related gene expression in a tissue-specific manner in aged rats

Many of the "hallmarks of aging" involve alterations in cellular and organismal metabolism. One pathway with the potential to impact several traditional markers of impaired function with aging is the PI3K/AKT metabolic pathway. Regulation of this pathway includes many aspects of cellular function, including protein synthesis, proliferation, and survival, as well as many downstream targets, including mTOR and FOXOs. Importantly, this pathway is pivotal to the function of every organ system in the human body. Thus, we investigated the expression of several genes along this pathway in multiple organs, including the brain, liver, and skeletal muscle, in aged subjects that had been on different experimental diets to regulate metabolic function since mid-life. Specifically, rats were fed a control ad lib diet (AL), a time restricted feeding diet (cTRF), or a time restricted feeding diet with ketogenic macronutrients (kTRF) for the majority of their adult lives (from 8 to 25 months). We previously reported that regardless of macronutrient ratio, TRF-fed rats in both macronutrient groups required significantly less training to acquire a biconditional association task than their ad lib fed counterparts. The current experiments expand on this work by quantifying metabolism-related gene expression across tissues and interrogating for potential relationships with cognitive performance. Within the brain, SIRT1 and MAPK8 were reduced in CA3 of kTRF-fed rats. Additionally, IGF1 expression was significantly upregulated in the CA1 of cTRF-fed rats, but this effect was ameliorated in the kTRF fed group. AKT and FOXO1 expression were significantly reduced in kTRF-fed rats within liver. Interestingly, AKT expression within the perirhinal cortex (PER) was higher in kTRF rats with the best cognitive performance, and FOXO1 expression was higher in the CA3 of AL-fed rats correlated with the poorest cognitive performance. Together, these data demonstrate diet- and tissue-specific alterations in metabolism-related gene expression and their correlation with cognitive status.

Association of occupational noise exposure and shift work with non-alcoholic fatty liver disease: a cross-sectional study of male workers in the Chinese automobile manufacturing industry

OBJECTIVE

This study aimed to determine the relationship between occupational noise, shift work and non-alcoholic fatty liver disease (NAFLD) in male workers in the automobile manufacturing industry.

DESIGN

Cross-sectional study.

SETTING

This study was carried out at the Guangzhou Twelfth People's Hospital using data from April to September 2022.

PARTICIPANTS

A total of 4672 eligible participants were included in the study.

PRIMARY AND SECONDARY OUTCOME MEASURES

Diagnosis of NAFLD was made using ultrasound. Noise was detected according to the Measurement of Physical Factors in the Workplace-Part 8: Noise. Environmental noise intensity was assessed using an EDGE personal noise dosimeter manufactured by CASELLA (UK). The working status of workers was investigated by questionnaire.

RESULTS

The OR of NAFLD was 1.39 (1.03, 1.88) in the cumulative noise exposure (CNE)≥95 group compared with CNE<85 group. Improved risk of NAFLD in workers with shift work compared with those without shift work (OR=1.35, 95% CI: 1.09, 1.68). As stratified analyses showed, the ORs of NAFLD prevalence related to occupational noise and shift work exposure appear to be increased in young workers. When both shift work and noise exposure work are present simultaneously, the synergy index between them was 0.47 (95% CI: 0.25, 0.89). Combined effects analysis revealed that the OR of NAFLD was 2.02 (95% CI: 1.34, 2.99) in CNE≥95 and cumulative length of night shifts work>2920 hours.

CONCLUSION

Occupational noise exposure may be an independent risk factor for NAFLD. It may synergistically affect disease when combined with night shift work, particularly among younger workers. These findings underscore the importance for companies to prioritise the management and training of younger workers, along with targeted occupational health education initiatives, as crucial measures for reducing the incidence of NAFLD.

Advances in biomarkers and diagnostic significance of organ aging

A complete understanding of aging is a critical first step in treating age-related diseases and postponing aging dysfunction in the context of an aging global population. Aging in organisms is driven by related molecular alterations that gradually occur in many organs. There has previously been a wealth of knowledge of how cells behave as they age, but when aging is investigated as a disease, the discovery and selection of aging biomarkers and how to diagnose the aging of the organism are crucial. Here, we provide a summary of the state of the field and suggest future potential routes for research on organ senescence markers. We reviewed research on biomarkers of risk of aging from the perspective of organ aging and summarized the biomarkers currently used on three scales. We emphasize that the combination of traditional markers with emerging multifaceted biomarkers may be a better way to diagnose age-related diseases.

The Role of Hypoxia in Longevity

Aging is marked by a progressive decrease in physiological function and reserve capacity, which results in increased susceptibility to diseases. Understanding the mechanisms of driving aging is crucial for extending health span and promoting human longevity. Hypoxia, marked by reduced oxygen availability, has emerged as a promising area of study within aging research. This review explores recent findings on the potential of oxygen restriction to promote healthy aging and extend lifespan. While the role of hypoxia-inducible factor 1 (HIF-1) in cellular responses to hypoxia is well-established, its impact on lifespan remains complex and context-dependent. Investigations in invertebrate models suggest a role for HIF-1 in longevity, while evidence in mammalian models is limited. Hypoxia extends the lifespan independent of dietary restriction (DR), a known intervention underlying longevity. However, both hypoxia and DR converge on common downstream effectors, such as forkhead box O (FOXO) and flavin-containing monooxygenase (FMOs) to modulate the lifespan. Further work is required to elucidate the molecular mechanisms underlying hypoxia-induced longevity and optimize clinical applications. Understanding the crosstalk between HIF-1 and other longevity-associated pathways is crucial for developing interventions to enhance lifespan and healthspan. Future studies may uncover novel therapeutic strategies to promote healthy aging and longevity in human populations.

Islet β-cell function preservation by different anti-diabetic treatments in Chinese elderly patients with type 2 diabetes mellitus

BACKGROUND

The preservation of islet β-cell function in elderly patients with type 2 diabetes mellitus (T2DM) is a top priority for diabetic control.

AIM

To assess the preservation of islet β-cell function among elderly Chinese patients with T2DM after different anti-diabetic treatments.

METHODS

In this longitudinal observational study, elderly patients with T2DM treated with insulin, oral antidiabetic drugs or a combination of both were enrolled to disclose their islet β-cell function between baseline and follow-up. Islet β-cell function was determined by the plasma Homeostasis Model for β-cell function (HOMA-β), C-peptide and area under the curve (AUC) based on oral glucose tolerance test. Changes in β-cell function (decrement or increment from baseline) between different therapy groups were the outcomes.

RESULTS

In total, 745 elderly patients (≥ 60 years) with T2DM [insulin monotherapy, n = 105; oral anti-diabetic drugs (OAD) monotherapy, n = 321; insulin plus OAD, n = 319] had their baseline and follow-up β-cell function assessed during a median observation period of 4.5 years (range, 3.0-7.2 years). Overall, islet β-cell function (HOMA-β, fasting C-peptide, fasting insulin, AUCc-pep, AUCins, AUCc-pep/AUCglu, AUCins/AUCglu) consistently deteriorated over time regardless of the three different antidiabetic treatments. No statistical differences in decrement were observed among the three groups regarding the islet β-cell function indices. All three groups showed an increased ratio of delayed insulin secretion response after 4.5 years of observation.

CONCLUSION

In Chinese elderly patients with T2DM, islet β-cell function progressively declines regardless of insulin supplement or insulin plus OAD treatments.

Multiomics identify the gene expression signature of the spinal cord during aging process

Age-related long-term disability is attracting increasing attention due to the growing ageing population worldwide. However, the current understanding of the senescent spinal cord remains insufficient. Bulk RNA sequencing reveals that 526 genes are upregulated and 300 genes are downregulated in senescent spinal cords. Pathway enrichment analysis of differentially expressed genes shows that senescence in spinal cords is related to phagosome function, neuroinflammation, ferroptosis, and necroptosis. Prediction of upstream transcription factors and interactome analysis identify Spi1 as a transcription factor that potentially plays a core role in senescent spinal cords. Spatial transcriptomics illustrates the spatial distribution of the transcriptomic landscape in both young and senescent spinal cords and identifies distinct neuronal and glial subtypes. The ferroptosis-associated gene Fth1 is upregulated in aged spinal cords. Flow cytometry reveals increased accumulation of free Fe2+ and ROS in senescent mixed glial cells; however, CCK-8 assays reveal that these cells are resistant to ferroptosis. SiRNA and lentivirus experiments indicate that the overexpression of Fth1 in normal mixed glial cells reduces their sensitivity to ferroptosis, whereas Fth1 knockdown increases their sensitivity to ferroptosis. In summary, spatial and bulk transcriptomics elucidate the transcriptional characteristics of young versus senescent spinal cords, thus highlighting the role of Fth1 in mediating ferroptosis resistance in senescent mixed glial cells.

Harnessing the fundamental roles of vitamins: the potent anti-oxidants in longevity

Aging is a complex and heterogeneous biological process characterized by telomere attrition, genomic instability, mitochondrial dysfunction, and disruption in nutrient sensing. Besides contributing to the progression of cancer, metabolic disorders, and neurodegenerative diseases, these manifestations of aging also adversely affect organ function. It is crucial to understand these mechanisms and identify interventions to modulate them to promote healthy aging and prevent age-related diseases. Vitamins have emerged as potential modulators of aging beyond their traditional roles in health maintenance. There is an increasing body of evidence that hormetic effects of vitamins are responsible for activating cellular stress responses, repair mechanisms, and homeostatic processes when mild stress is induced by certain vitamins. It is evident from this dual role that vitamins play a significant role in preventing frailty, promoting resilience, and mitigating age-related cellular damage. Moreover, addressing vitamin deficiencies in the elderly could have a significant impact on slowing aging and extending life expectancy. A review of recent advances in the role of vitamins in delaying aging processes and promoting multiorgan health is presented in this article. The purpose of this paper is to provide a comprehensive framework for using vitamins as strategic tools for fostering longevity and vitality. It offers a fresh perspective on vitamins' role in aging research by bridging biological mechanisms and clinical opportunities.

Steroidogenic acute regulatory protein mediated variations of gender-specific sex neurosteroids in Alzheimer's disease: Relevance to hormonal and neuronal imbalance

The steroidogenic acute regulatory (StAR) protein mediates the rate-liming step in neuro/steroid biosynthesis. Multifaceted and delicate changes during aging, disrupting hormonal and neuronal homeostasis, constitute human senescence, an inevitable phenomenon that attributes to increased morbidity and mortality. Aging, along with progressive decreases in bioactive neurosteroids, is the primary risk factor for Alzheimer's disease (AD), which preferentially impacts two-thirds of women and one-third of men. AD is neuropathologically characterized by the accumulation of extracellular amyloid-β and intracellular phosphorylated Tau containing neurofibrillary tangles, resulting in dementia. Postmortem brains pertaining to gender-specific AD patients exhibit varied suppression of StAR and sex neurosteroid levels compared with age-matched cognitively healthy subjects, in which the attenuation of StAR is inversely correlated with the AD pathological markers. Interestingly, retinoid signaling upregulates StAR-motivated neurosteroid biosynthesis and reinstates various neurodegenerative vulnerabilities that promote AD pathogenesis. This review summarizes current understanding of StAR-driven alterations of sex neurosteroids in gender-specific AD risks and provides biochemical and molecular insights into therapeutic interventions for preventing and/or alleviating dementia for healthy aging.

The impact of aging on neutrophil functions and the contribution to periodontitis

The increasing aging population and aging-associated diseases have become a global issue for decades. People over 65 show an increased prevalence and greater severity of periodontitis, which poses threats to overall health. Studies have demonstrated a significant association between aging and the dysfunction of neutrophils, critical cells in the early stages of periodontitis, and their crosstalk with macrophages and T and B lymphocytes to establish the periodontal lesion. Neutrophils differentiate and mature in the bone marrow before entering the circulation; during an infection, they are recruited to infected tissues guided by the signal from chemokines and cytokines to eliminate invading pathogens. Neutrophils are crucial in maintaining a balanced response between host and microbes to prevent periodontal diseases in periodontal tissues. The impacts of aging on neutrophils' chemotaxis, anti-microbial function, cell activation, and lifespan result in impaired neutrophil functions and excessive neutrophil activation, which could influence periodontitis course. We summarize the roles of neutrophils in periodontal diseases and the aging-related impacts on neutrophil functional responses. We also explore the underlying mechanisms that can contribute to periodontitis manifestation in aging. This review could help us better understand the pathogenesis of periodontitis, which could offer novel therapeutic targets for periodontitis.

Dietary caloric input and tumor growth accelerate senescence and modulate liver and adipose tissue crosstalk

Metabolic alterations are related to tumorigenesis and other age-related diseases that are accelerated by "Westernized" diets. In fact, hypercaloric nutrition is associated with an increased incidence of cancers and faster aging. Conversely, lifespan-extending strategies, such as caloric restriction, impose beneficial effects on both processes. Here, we investigated the metabolic consequences of hypercaloric-induced aging on tumor growth in female mice. Our findings indicate that a high-fat high-sucrose diet increases tumor growth mainly due to the boosted oxidation of glucose and fatty acids. Consequently, through an increased expression of lactate, IGFBP3, and PTHLH, tumors modulate liver and white adipose tissue metabolism. In the liver, the induced tumor increases fibrosis and accelerates the senescence process, despite the lower systemic pro-inflammatory state. Importantly, the induced tumor induces the wasting and browning of white adipose tissue, thereby reversing diet-induced insulin resistance. Finally, we suggest that tumor growth alters liver-adipose tissue crosstalk that upregulates Fgf21, induces senescence, and negatively modulates lipids and carbohydrates metabolism even in caloric-restricted-fed mice.

Unraveling the ROS-Inflammation-Immune Balance: A New Perspective on Aging and Disease

Increased entropy is a common cause of disease and aging. Lifespan entropy is the overall increase in disorder caused by a person over their lifetime. Aging leads to the excessive production of reactive oxygen species (ROS), which damage the antioxidant system and disrupt redox balance. Organ aging causes chronic inflammation, disrupting the balance of proinflammatory and anti-inflammatory factors. Inflammaging, which is a chronic low-grade inflammatory state, is activated by oxidative stress and can lead to immune system senescence. During this process, entropy increases significantly as the body transitions from a state of low order to high disorder. However, the connection among inflammation, aging, and immune system activity is still not fully understood. This review introduces the idea of the ROS-inflammation-immune balance for the first time and suggests that this balance may be connected to aging and the development of age-related diseases. We also explored how the balance of these three factors controls and affects age-related diseases. Moreover, imbalance in the relationship described above disrupts the regular structures of cells and alters their functions, leading to cellular damage and the emergence of a disorganized state marked by increased entropy. Maintaining a low entropy state is crucial for preventing and reversing aging processes. Consequently, we examined the current preclinical evidence for antiaging medications that target this balance. Ultimately, comprehending the intricate relationships between these three factors and the risk of age-related diseases in organisms will aid in the development of clinical interventions that promote long-term health.

Discovering geroprotectors through the explainable artificial intelligence-based platform AgeXtend

Aging involves metabolic changes that lead to reduced cellular fitness, yet the role of many metabolites in aging is unclear. Understanding the mechanisms of known geroprotective molecules reveals insights into metabolic networks regulating aging and aids in identifying additional geroprotectors. Here we present AgeXtend, an artificial intelligence (AI)-based multimodal geroprotector prediction platform that leverages bioactivity data of known geroprotectors. AgeXtend encompasses modules that predict geroprotective potential, assess toxicity and identify target proteins and potential mechanisms. We found that AgeXtend accurately identified the pro-longevity effects of known geroprotectors excluded from training data, such as metformin and taurine. Using AgeXtend, we screened ~1.1 billion compounds and identified numerous potential geroprotectors, which we validated using yeast and Caenorhabditis elegans lifespan assays, as well as exploring microbiome-derived metabolites. Finally, we evaluated endogenous metabolites predicted as senomodulators using senescence assays in human fibroblasts, highlighting AgeXtend's potential to reveal unidentified geroprotectors and provide insights into aging mechanisms.

Time restricted feeding with or without ketosis influences metabolism-related gene expression in a tissue-specific manner in aged rats

Many of the 'hallmarks of aging' involve alterations in cellular and organismal metabolism. One pathway with the potential to impact several traditional markers of impaired function with aging is the PI3K/AKT metabolic pathway. Regulation of this pathway includes many aspects of cellular function, including protein synthesis, proliferation and survival, as well as many downstream targets, including mTOR and FOXOs. Importantly, this pathway is pivotal to the function of every organ system in the human body. Thus, we investigated the expression of several genes along this pathway in multiple organs, including the brain, liver and skeletal muscle, in aged subjects that had been on different experimental diets to regulate metabolic function since mid-life. Specifically, rats were fed a control ad lib diet (AL), a time restricted feeding diet (cTRF), or a time restricted feeding diet with ketogenic macronutrients (kTRF) for the majority of their adult lives (from 8-25 months). We previously reported that regardless of macronutrient ratio, TRF-fed rats in both macronutrient groups required significantly less training to acquire a biconditional association task than their ad lib fed counterparts. The current experiments expand on this work by quantifying metabolism-related gene expression across tissues and interrogating for potential relationships with cognitive performance. AKT expression was significantly reduced in kTRF fed rats within liver and muscle tissue. However, AKT expression within the perirhinal cortex (PER) was higher in kTRF rats with the best cognitive performance. Within CA3, higher levels of FOXO1 gene expression correlated with poorer cognitive performance in ad libitum fed rats. Together, these data demonstrate diet- and tissue-specific alterations in metabolism-related gene expression and their correlation with cognitive status.

Life History Differences Between Lepidoptera Larvae and Blattodea Nymphs Lead to Different Energy Allocation Strategies and Cellular Qualities

Different life histories result in different strategies to allocate energy in biosynthesis, including growth and reproduction, and somatic maintenance. One of the most notable life history differences between Lepidoptera and Blattodea species is that the former grow much faster than the latter, and during metamorphosis, a large amount of tissue in Lepidoptera species disintegrates. In this review, using Lepidoptera caterpillars and cockroach nymphs as examples, we show that, due to these differences in growth processes, cockroach nymphs spend 20 times more energy on synthesizing one unit of biomass (indirect cost of growth) than butterfly caterpillars. Because of the low indirect cost of growth in caterpillars, the fraction of metabolic energy allocated to growth is six times lower, and that for maintenance is seven times higher in caterpillars, compared to cockroach nymphs, despite caterpillar's higher growth rates. Moreover, due to the higher biosynthetic energy cost in cockroach nymphs, they have better cellular qualities, including higher proteasomal activity for protein quality control and higher resistance to oxidative stress. We also show that under food restriction conditions, the fraction of assimilated energy allocated to growth was reduced by 120% in cockroach nymphs, as they lost body weight under food restriction, while this reduction was only 14% in hornworms, and the body mass increased at a lower rate. Finaly, we discuss future research, especially the difference in adult lifespans associated with the energetic differences.

Neurogenic Aging After Spinal Cord Injury: Highlighting the Unique Characteristics of Aging After Spinal Cord Injury

Emanating from several decades of study into the effects of the aging process after spinal cord injury (SCI), "accelerated aging" has become a common expression as the SCI accelerates the onset of age-related pathologies. However, the aging process follows a distinct trajectory, characterized by unique patterns of decline that differ from those observed in the general population without SCI. Aging brings significant changes to muscles, bones, and hormones, impacting overall physical function. Muscle mass and strength begin to decrease with a reduction in muscle fibers and impaired repair mechanisms. Bones become susceptible to fractures as bone density decreases. Hormonal changes combined with decreased physical activity accelerate the reduction of muscle mass and increase in body fat. Muscle atrophy and skeletal muscle fiber type transformation occur rapidly and in a unique pattern after SCI. Bone loss develops more rapidly and results in an increased risk of fractures in body regions unique to individuals with SCI. Other factors, such as excessive adiposity, decreased testosterone and human growth hormone, and increased systemic inflammation, contribute to a higher risk of neuropathically driven obesity, dyslipidemia, glucose intolerance, insulin resistance, and increasing cardiovascular disease risk. Cardiorespiratory changes after SCI result in lower exercise heart rates, decreased oxygenation, and mitochondrial dysfunction. While it is important to acknowledge the accelerated aging processes after SCI, it is essential to recognize the distinct differences in the aging process between individuals without physical disabilities and those with SCI. These differences, influenced by neuropathology, indicate that it may be more accurate to describe the aging process in individuals with chronic SCI as neurogenic accelerated aging (NAA). Research should continue to address conditions associated with NAA and how to ameliorate the accelerated rate of premature age-related conditions. This review focuses on the NAA processes and the differences between them and the aging process in those without SCI. Recommendations are provided to help slow the development of premature aging conditions.

Base-editing corrects metabolic abnormalities in a humanized mouse model for glycogen storage disease type-Ia

Glycogen storage disease type-Ia patients, deficient in the G6PC1 gene encoding glucose-6-phosphatase-α, lack blood glucose control, resulting in life-threatening hypoglycemia. Here we show our humanized mouse model, huR83C, carrying the pathogenic G6PC1-R83C variant displays the phenotype of glycogen storage disease type-Ia and dies prematurely. We evaluate the efficacy of BEAM-301, a formulation of lipid nanoparticles containing a newly-engineered adenine base editor, to correct the G6PC1-R83C variant in huR83C mice and monitor phenotypic correction through one year. BEAM-301 can correct up to ~60% of the G6PC1-R83C variant in liver cells, restores blood glucose control, improves metabolic abnormalities of the disease, and confers long-term survival to the mice. Interestingly, just ~10% base correction is therapeutic. The durable pharmacological efficacy of base editing in huR83C mice supports the development of BEAM-301 as a potential therapeutic for homozygous and compound heterozygous glycogen storage disease type-Ia patients carrying the G6PC1-R83C variant.

Crosstalk between adipogenesis and aging: role of polyphenols in combating adipogenic-associated aging

In the last forty years, the number of people over 60 years of age has increased significantly owing to better nutrition and lower rates of infectious diseases in developing countries. Aging significantly impacts adipose tissue, which plays crucial role in hormone regulation and energy storage. This can lead to imbalances in glucose, and overall energy homeostasis within the body. Aging is irreversible phenomena and potentially causing lipid infiltration in other organs, leading to systemic inflammation, metabolic disorders. This review investigates various pathways contributing to aging-related defects in adipogenesis, such as changes in adipose tissue function and distribution. Polyphenols, a diverse group of natural compounds, can mitigate aging effects via free radicals, oxidative stress, inflammation, senescence, and age-related diseases. Polyphenols like resveratrol, quercetin and EGCG exhibit distinct mechanisms and regulate crucial pathways, such as the TGF-β, AMPK, Wnt, PPAR-γ, and C/EBP transcription factors, and influence epigenetic modifications, such as DNA methylation and histone modification. This review highlights the critical importance of understanding the intricate relationship between aging and adipogenesis for optimizing well-being with increasing age. These findings highlight the therapeutic potential of polyphenols like quercetin and resveratrol in enhancing adipose tissue function and promoting healthy aging.

iTRAQ-Based Proteomic Profiling of Skin Aging Protective Effects of Tremella fuciformis-Derived Polysaccharides on D-Galactose-Induced Aging Mice

In the present study, a heteromannan primarily composed of mannose, fucose, xylose, glucose, and arabinose at a molar ratio of 4.78:1.18:1:0.82:0.11 containing a low proportion of glucuronic acid with weight-average molecular weights of 3.6 × 106 Da, named NTP, was prepared from the fruiting body of Tremella fuciformis. The anti-skin-aging effects of NTP on d-Galactose-induced aging mice and the biological mechanisms were investigated by an iTRAQ-based proteomics approach. NTP substantially mitigated skin aging characterized by a decreased loss of hydroxyproline and hyaluronic acid and reduced oxidative stress in the skin. Moreover, 43 differentially expressed proteins (DEPs) were identified in response to NTP, of which 23 were up-regulated and 20 were down-regulated. Bioinformatics analysis revealed that these DEPs were mainly involved in the biological functions of cellular and metabolic regulations, immune system responses, and structural components. The findings provided new insights into the biological mechanisms underlying the anti-skin-aging actions of T. fuciformis-derived polysaccharides and facilitated NTP applications in naturally functional foods.

Updating and calibrating the Real-World Progression In Diabetes (RAPIDS) model in a non-Veterans Affairs population

OBJECTIVES

To present the Real-World Progression In Diabetes (RAPIDS) 2.0 Risk Engine, the only simulation model to study the long-term trajectories of outcomes arising from dynamic sequences of glucose-lowering treatments in type 2 diabetes (T2DM).

RESEARCH DESIGN AND METHODS

The RAPIDS model's risk equations were re-estimated using a Least Absolute Shrinkage and Selection Operator (LASSO)-based regularization of features that spanned baseline data from the last two quarters of current time and interactions with age. These equations were supplemented with estimates for the impact of dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists, and sodium-glucose cotransporter-2 inhibitor classes of drugs as monotherapies and their combinations with metformin based on newer trial data and comprehensive meta-analyses. The probabilistic RAPIDS 2.0 model was calibrated (N = 25 000) and validated (N = 263 816) using electronic medical records (EMR) data between 2008 and 2021 from a national network of US healthcare organizations.

RESULTS

The EMR-based cohort had a mean age of 61 years at baseline, with 50% women, 70% non-Hispanic White individuals and 20% non-Hispanic Black individuals, and was followed for 17.5 quarters (range: 3-50). The final RAPIDS 2.0 risk engine accurately predicted the long-term trajectories of all nine biomarkers and nine outcomes in the hold-out validation sample. Similar accuracies in predictions were observed in each of the 14 subgroups studied.

CONCLUSION

The RAPIDS 2.0 model demonstrated valid long-term predictions of outcomes in individuals with T2DM in the United States as a function of dynamic sequences of treatment use patterns. This highlights its potential to project long-term comparative effectiveness between alternative sequences of glucose-lowering treatment uses in the United States.

Metabolomics Dysfunction in Replicative Senescence of Periodontal Ligament Stem Cells Regulated by AMPK Signaling Pathway

Periodontal ligament mesenchymal stem cells (PDLSCs) are a promising cell resource for stem cell-based regenerative medicine in dentistry, but they inevitably acquire a senescent phenotype after prolonged in vitro expansion. The key regulators of PDLSCs during replicative senescence remain unclear. Here, we sought to elucidate the role of metabolomic changes in determining the cellular senescence of PDLSCs. PDLSCs were cultured to passages 4, 10, and 20. The senescent phenotypes of PDLSCs were detected, and metabolomics analysis was performed. We found that PDLSCs manifested senescence phenotype during passaging. Metabolomics analysis showed that the metabolism of replicative senescence in PDLSCs varied significantly. The AMP-activated protein kinase (AMPK) signaling pathway was closely related to adenosine monophosphate (AMP) levels. The AMP:ATP ratio increased in senescent PDLSCs; however, the levels of p-AMPK, FOXO1 and FOXO3a decreased with senescence. We treated PDLSCs with an activator of the AMPK pathway (AICAR) and observed that the phosphorylated AMPK level at P20 PDLSCs was partially restored. These data delineate that the metabolic process of PDLSCs is active in the early stage of senescence and attenuated in the later stages of senescence; however, the sensitivity of AMPK phosphorylation sites is impaired, causing senescent PDLSCs to fail to respond to changes in energy metabolism.

Nutrition, GH/IGF-1 signaling, and cancer

Cancer is the second leading cause of death in the United States and among the most prevalent diseases globally, with an incidence expected to grow because of smoking, pollution, poor dietary habits, obesity, and the rise in the older population. Given their ability to reduce risk factors, albeit with varying efficacy, nutrition and fasting could help prevent cancer and other age-related disorders. Calorie restriction (CR), various forms of intermittent fasting (IF) or periodic fasting (PF), and fasting-mimicking diets (FMDs) have been shown to improve health span, increase lifespan, and prevent or postpone cancer in rodents. The effects of specific diets and fasting regimens on aging and cancer appear to be mediated in part by the reduction in the activity of the growth hormone (GH)/insulin-like-growth-factor-I (IGF-1) axis. Nevertheless, recent data indicate that the alternation of low and normal levels of these hormones and factors may be ideal for optimizing longevity and function. Here, we review the role of nutrition, CR, and fasting/FMD on cancer, focusing on the hypothesis that the modulation of GH, IGF-1, and insulin signaling partly mediates the effect of these dietary interventions on cancer prevention.

Effects of excess sodium consumption on arterial function in C57BL/6 mice

Excess sodium consumption contributes to arterial dysfunction in humans. The C57BL/6 strain of mice has been used to identify mechanisms by which arterial dysfunction occurs after excess sodium consumption. However, there are concerns that C57BL/6 mice have strain-specific resistance to high-sodium (HS) diet-induced hypertension. To address this concern, we performed a meta-analysis to determine if excess sodium consumption in C57BL/6 mice induces arterial dysfunction. Databases were searched for HS versus standard diet studies that measured arterial function [i.e., systolic blood pressure (BP), endothelium-dependent dilation (EDD), and central arterial stiffness] in C57BL/6 mice. A total of 39 studies were included, demonstrating that the HS condition resulted in higher systolic BP than control mice with a mean difference of 9.8 mmHg (95% confidence interval [CI] = [5.6, 14], P < 0.001). Subgroup analysis indicated that the systolic BP was higher in HS compared with the control condition when measured during night compared with daytime with telemetry (P < 0.001). We also identified that the difference in systolic BP between HS and control was ∼2.5-fold higher when administered through drinking water than through food (P < 0.001). A total of 12 studies were included, demonstrating that the HS condition resulted in lower EDD than control with a weighted mean difference of -12.0% (95% CI = [-20.0, -4.1], P = 0.003). It should be noted that there was considerable variability across studies with more than half of the studies showing no effect of the HS condition on systolic BP or EDD. In summary, excess sodium consumption elevates systolic BP and impairs EDD in C57BL/6 mice.NEW & NOTEWORTHY C57BL/6 mice are perceived as resistant to high-sodium diet-induced arterial dysfunction. This meta-analysis demonstrates that excess sodium consumption elevates blood pressure and impairs endothelium-dependent dilation in C57BL/6 mice. Nighttime measurements show more pronounced blood pressure elevation. In addition, sodium administration via drinking water, compared with food, induces a greater blood pressure elevation. These findings may be influenced by outlier studies, as the majority of studies showed no adverse effect of excess sodium consumption on arterial function.

Particulate matter 2.5 accelerates aging: Exploring cellular senescence and age-related diseases

Exposure to Particulate matter 2.5 (PM2.5) accelerates aging, causing declines in tissue and organ function, and leading to diseases such as cardiovascular, neurodegenerative, and musculoskeletal disorders. PM2.5 is a major environmental pollutant and an exogenous pathogen in air pollution that is now recognized as an accelerator of human aging and a predisposing factor for several age-related diseases. In this paper, we seek to elucidate the mechanisms by which PM2.5 induces cellular senescence, such as genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, and mitochondrial dysfunction, and age-related diseases. Our goal is to increase awareness among researchers within the field of the toxicity of environmental pollutants and to advocate for personal and public health initiatives to curb their production and enhance population protection. Through these endeavors, we aim to promote longevity and health in older adults.

A cocktail of rapamycin, acarbose, and phenylbutyrate prevents age-related cognitive decline in mice by targeting multiple aging pathways

Aging is a primary risk factor for cognitive impairment and exacerbates multiple biological processes in the brain, including but not limited to nutrient sensing, insulin signaling, and histone deacetylation activity. Therefore, a pharmaceutical intervention of aging that targets distinct but overlapping pathways provides a basis for testing combinations of drugs as a cocktail. Our previous study showed that middle-aged mice treated with a cocktail of rapamycin, acarbose, and phenylbutyrate for 3 months had increased resilience to age-related cognitive decline. This finding provided the rationale to investigate the transcriptomic and molecular changes within the brains of mice that received this cocktail treatment or control treatment. Transcriptomic profiles were generated through ribonucleic acid (RNA) sequencing, and pathway analysis was performed by gene set enrichment analysis to evaluate the overall RNA message effect of the drug cocktail. Molecular endpoints representing aging pathways were measured using immunohistochemistry to further validate the attenuation of brain aging in the hippocampus of mice that received the cocktail treatment, each individual drug or control. Results showed that biological processes that enhance aging were suppressed, with an increased trend of autophagy in the brains of mice given the drug cocktail. The molecular endpoint assessments indicated that treatment with the drug cocktail was overall more effective than any of the individual drugs for relieving cognitive impairment by targeting multiple aging pathways.

Chronic stress and functional health in older adults with concerns about falling: a study protocol of a randomized controlled trial with multicomponent exercise intervention (FEARFALL)

BACKGROUND

Maintenance of physical function, mobility, and independent living are important goals for older adults. However, concerns about falling (CaF) play a central role in the vicious cycle of CaF, inflammation, loss of muscle mass, and decreasing physical function ultimately resulting in negative health outcomes. CaF, like other states of chronic stress and anxiety, can be considered as enduring adverse stimuli affecting the stress systems and the inflammatory system. Therefore, the aim of this study is to investigate whether a reduction of CaF leads to a reduction of stress and therefore possibly reduces chronic low-grade inflammation. Understanding the role and directionality of the effects of inflammation on CaF increases our understanding of age-related loss of mobility and physical function.

METHODS

In this study, community-dwelling older adults, aged 70 years and older, will be randomly assigned to either a 4-month, multi-component intervention with exercise training and cognitive-behavioral components or to a sham control group with light stretching exercises, cognitive training, and educational health lectures. For the operationalization of specific CaF, the Falls Efficacy Scale-International will be used. Stress and related psychological symptoms will be monitored using established self-reports and by measuring salivary cortisol. Concentrations of C-reactive protein, interleukin 6, interleukin 10, and tumor-necrosis-factor-alpha, as well as gene expression of selected inflammatory transcripts, will be used as surrogate parameters of the inflammatory status at baseline, after the 4-month intervention and 8-month follow-up.

DISCUSSION

This study will be the first to test whether CaF are related with stress system activity or reactivity or with markers of inflammation in the context of a multi-component intervention with exercise training and cognitive-behavioral components addressing CaF. The reduction of specific CaF or general psychological symptoms should reverse alterations in stress systems, and / or slow down low-grade inflammation. Changes in activity, as well as psychological and biological pathways leading from CaF to muscle loss will be measured, to disentangle the individual contribution to sarcopenia, and to provide an additional pathway to break or slow-down the vicious cycle of CaF and sarcopenia.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS): DRKS00029171 . Registered 22 July 2022.

Targeting IGF1/IGF1r signaling relieve pain and autophagic dysfunction in NTG-induced chronic migraine model of mice

BACKGROUND

Chronic migraine is a severe and common neurological disorder, yet its precise physiological mechanisms remain unclear. The IGF1/IGF1r signaling pathway plays a crucial role in pain modulation. Studies have shown that IGF1, by binding to its receptor IGF1r, activates a series of downstream signaling cascades involved in neuronal survival, proliferation, autophagy and functional regulation. The activation of these pathways can influence nociceptive transmission. Furthermore, alterations in IGF1/IGF1r signaling are closely associated with the development of various chronic pain conditions. Therefore, understanding the specific mechanisms by which this pathway contributes to pain is of significant importance for the development of novel pain treatment strategies. In this study, we investigated the role of IGF1/IGF1r and its potential mechanisms in a mouse model of chronic migraine.

METHODS

Chronic migraine was induced in mice by repeated intraperitoneal injections of nitroglycerin. Mechanical and thermal hypersensitivity responses were assessed using Von Frey filaments and radiant heat, respectively. To determine the role of IGF1/IGF1r in chronic migraine (CM), we examined the effects of the IGF1 receptor antagonist ppp (Picropodophyllin) on pain behaviors and the expression of calcitonin gene-related peptide (CGRP) and c-Fos.

RESULT

In the nitroglycerin-induced chronic migraine model in mice, neuronal secretion of IGF1 is elevated within the trigeminal nucleus caudalis (TNC). Increased phosphorylation of the IGF1 receptor occurs, predominantly co-localizing with neurons. Treatment with ppp alleviated basal mechanical hypersensitivity and acute mechanical allodynia. Furthermore, ppp ameliorated autophagic dysfunction and reduced the expression of CGRP and c-Fos.

CONCLUSION

Our findings demonstrate that in the chronic migraine (CM) model in mice, there is a significant increase in IGF1 expression in the TNC region. This upregulation of IGF1 leads to enhanced phosphorylation of IGF1 receptors on neurons. Targeting and inhibiting this signaling pathway may offer potential preventive strategies for mitigating the progression of chronic migraine.

Calorie restriction and life-extending mutation downregulate miR-34a to facilitate lipid metabolism in the liver

Ames dwarf mice (df/df) display delayed aging relative to their normal (N) siblings, living approximately 40-60 % longer. As such, investigating the mechanisms that enable these organisms to have extended lifespan is useful for the development of interventions to slow aging and deter age-related disease. Nonalcoholic fatty liver disease (NAFLD) is a condition that is characterized by the accumulation of excess adipose tissue in the liver. Previous studies highlight the potential of calorie restriction (CR) in promoting longevity, but little is known about its effects on the biomolecular processes that govern NAFLD. In this study, we examined the role of 6-month CR on genes regulating lipid metabolism in the livers of long-living df/df mice and their N littermates. Importantly, our findings showed significant downregulation of miR-34a-5p in N-CR mice and df/df mice regardless of dietary regimen. Alongside, our RT-PCR results indicated that downregulation of miR-34a-5p is correlated with the expression of metabolism-associated mRNAs involved in modulating the processes of de novo lipogenesis (DNL), fatty acid oxidation (FAO), very-low density lipoprotein transport (VLDL-T), and reverse cholesterol transport (RCT). To further verify the role of miR-34a-5p in regulating metabolic processes, we transfected the human liver cancer (HepG2) cell line with miR-34a mimic, and studied its effect on direct targets Sirt1, Ampk, and Ppara as well as downstream lipid transport regulating genes. Our findings suggest that CR and df/df life extending mutation are robust drivers of the miR-34a-5p signaling pathway and prevent the pathogenesis of age-related diseases by improving overall lipid homeostasis.

Polygenic prediction of human longevity on the supposition of pervasive pleiotropy

The highly polygenic nature of human longevity renders pleiotropy an indispensable feature of its genetic architecture. Leveraging the genetic correlation between aging-related traits (ARTs), we aimed to model the additive variance in lifespan as a function of the cumulative liability from pleiotropic segregating variants. We tracked allele frequency changes as a function of viability across different age bins and prioritized 34 variants with an immediate implication on lipid metabolism, body mass index (BMI), and cognitive performance, among other traits, revealed by PheWAS analysis in the UK Biobank. Given the highly complex and non-linear interactions between the genetic determinants of longevity, we reasoned that a composite polygenic score would approximate a substantial portion of the variance in lifespan and developed the integrated longevity genetic scores (iLGSs) for distinguishing exceptional survival. We showed that coefficients derived from our ensemble model could potentially reveal an interesting pattern of genomic pleiotropy specific to lifespan. We assessed the predictive performance of our model for distinguishing the enrichment of exceptional longevity among long-lived individuals in two replication cohorts (the Scripps Wellderly cohort and the Medical Genome Reference Bank (MRGB)) and showed that the median lifespan in the highest decile of our composite prognostic index is up to 4.8 years longer. Finally, using the proteomic correlates of iLGS, we identified protein markers associated with exceptional longevity irrespective of chronological age and prioritized drugs with repurposing potentials for gerotherapeutics. Together, our approach demonstrates a promising framework for polygenic modeling of additive liability conferred by ARTs in defining exceptional longevity and assisting the identification of individuals at a higher risk of mortality for targeted lifestyle modifications earlier in life. Furthermore, the proteomic signature associated with iLGS highlights the functional pathway upstream of the PI3K-Akt that can be effectively targeted to slow down aging and extend lifespan.

Effect of Single Session of Swedish Massage on Circulating Levels of Interleukin-6 and Insulin-like Growth Factor 1

Massage therapy increases muscle blood flow and heat, relieving pain, improving immune function, and increasing vagal activity. The mechanisms are unclear. Muscles release cytokines and other peptides called myokines. These myokines exert their effects on different tissues and organs in para-, auto-, and endocrine fashion. The aim of this intervention study was to investigate if massage therapy affects circulating myokine levels. A total of 46 healthy, normal-weight subjects (15 men) aged 18-35 were recruited. Forty-five minutes of massage Swedish therapy was applied to the back and hamstrings. Blood samples via cannula were taken at the baseline, during the massage (30 min), end of the massage (45 min), and 30 min and 1 h after the massage. Interleukin 6 (IL-6) and insulin-like growth factor 1 (IGF-1) were measured as surrogate markers by ELISAs. There was a significant increase in IL-6 from 1.09 pg/mL to 1.85 pg/mL over time (Wilks' Lambda Value 0.545, p < 0.000; repeated measures ANOVA). Pair-wise comparisons showed a significant increase after 1 h of massage. No significant increase was observed in IGF-1 levels. The change in myokine levels was not correlated with muscle mass (p = 0.16, 0.74). The increase in IL-6 suggests that there might be anti-inflammatory effects, affecting glucose and lipid metabolism pathways via IL-6 signaling to muscles, fat tissue, and the liver.

Non-pharmaceutical interventions and epigenetic aging in adults: Protocol for a scoping review

INTRODUCTION

Aging is the strongest risk factor for most chronic diseases. The rising burden of an aging population and non-communicable diseases (NCDs), contributes to escalating costs for society. Several non-pharmaceutical interventions can lower the risk of NCDs, including common mental disorders (CMDs), and may slow down biological aging, as evidenced by outcome markers such as epigenetic clocks. However, a comprehensive overview of whether and which non-pharmaceutical interventions may impact human epigenetic aging is missing. Synthesizing evidence of interventions on epigenetic aging that can be adopted by a wider population is key to guide healthy aging initiatives and to reduce the burden of NCDs and CMDs. This scoping review will identify and assess non-pharmaceutical interventions aimed to slow down epigenetic aging, including their intervention components, and the mode used for intervention delivery.

METHODS AND ANALYSIS

This protocol will include single- and multicomponent intervention studies that target individuals ≥ 18 years of age and use epigenetic clocks as primary or secondary outcomes. Five electronic databases will be searched for studies between July 2011 until December 2023. The final search will include the search terms adults, non-pharmaceutical interventions, epigenetic aging and their respective synonyms. We will include randomized controlled trials, non-randomized controlled studies, cohort studies, and case-control studies. Additionally, the reference list of other reviews will be screened for relevant articles. Study selection is carried out based on the defined eligibility criteria by two authors. Quality and risk of bias for the included studies will be assessed using the Critical Appraisal Skills Programme (CASP) checklist. Data extraction will include generic key information such as the research question and results, the intervention components, and specific epigenetic outcome measures used. Further data regarding the delivery mode of the treatment protocol will be collected.

ETHICS AND DISSEMINATION

This scoping review will summarize the characteristics of non-pharmaceutical intervention studies on epigenetic aging. This review will be the first step to formally identify key intervention components and delivery modes to guide future research on healthy aging interventions. The results will be disseminated through a peer-reviewed publication and presented at relevant conferences. This review will synthesize information from available publications and does not require further ethical approval.

REGISTRATION DETAILS

Open Science Framework https://doi.org/10.17605/OSF.IO/FEHNB.

Maternal α-casein deficiency extends the lifespan of offspring and programmes their body composition

Early nutrition has significant effects on physiological outcomes during adult life. We have analysed the effect of maternal α-casein (CSN1S1) deficiency on the physiological fate of dams and their offspring. α-casein deficiency reduces maternal milk protein concentration by more than 50% and attenuates the growth of pups to 27% (p < 0.001) of controls at the point of weaning. This is associated with a permanent reduction in adult body weight (- 31% at 25 weeks). Offspring nursed by α-casein deficient dams showed a significantly increased lifespan (+ 20%, χ2: 10.6; p = 0.001). Liver transcriptome analysis of offspring nursed by α-casein deficient dams at weaning revealed gene expression patterns similar to those found in dwarf mice (reduced expression of somatotropic axis signalling genes, increased expression of xenobiotic metabolism genes). In adult mice, the expression of somatotropic axis genes returned to control levels. This demonstrates that, in contrast to dwarf mice, attenuation of the GH-IGF signalling axis in offspring nursed by α-casein deficient dams is transient, while the changes in body size and lifespan are permanent. Offspring nursed by α-casein deficient dams showed permanent changes in body composition. Absolute and relative adipose tissue weights (p < 0.05), the percentage of body fat (p < 0.001) as well as adipocyte size in epididymal white adipose tissue are all reduced. Serum leptin levels were 25% of those found in control mice (p < 0.001). Liver lipid content and lipid composition were significantly altered in response to postnatal nutrition. This demonstrates the nutrition in early life programmes adult lipid metabolism, body composition and lifespan.

A study of baseline data from SPRINT: Exploring lipid profile changes in middle-aged and elderly patients

The elderly population is at a higher risk of cardiovascular complications, and dyslipidemia plays a significant role as a contributing factor. Chronic kidney disease (CKD) patients are prone to lipid abnormalities, further increasing the risk of cardiovascular complications. We aimed to investigate the lipid profile characteristics of the middle-aged and elderly population, particularly CKD patients. We conducted a cross-sectional study using baseline data from the Systolic Blood Pressure Intervention Trial (SPRINT). It was examined how lipid profiles are affected by age within the general population, and how BMI and lipid characteristics are affected by CKD subtype. Among 8746 participants, we observed a decreasing trend in LnTAG (natural logarithm of Triacylglycerol) and total Cholesterol (CHR) levels with increasing age, while high-density lipoprotein cholesterol (HDL-C) levels increased with age. In the CKD and non-CKD subgroups created through propensity score matching based on age, sex, and race, CKD individuals exhibited significantly higher average LnTAG levels across all age groups compared to the non-CKD group. Multivariable linear regression analysis, controlling for confounding variables, revealed a negative correlation between LnTAG and estimated glomerular filtration rate (eGFR) (r = -0.002, p < 0.001). HDL-C showed a positive correlation with eGFR (r = 0.001, p < 0.001). [Correction added on 1 July 2024, after first online publication: The value of r in the preceding sentence has been updated to r = 0.001.] That is, in the middle-aged and elderly population, age demonstrated a negative correlation with total CHR and TAG levels, while exhibiting a positive correlation with HDL-C levels. CKD patients exhibited relatively higher TAG levels, which were positively associated with CKD progression.

ADP-ribosylation, a multifaceted modification: Functions and mechanisms in aging and aging-related diseases

Aging, a complex biological process, plays key roles the development of multiple disorders referred as aging-related diseases involving cardiovascular diseases, stroke, neurodegenerative diseases, cancers, lipid metabolism-related diseases. ADP-ribosylation is a reversible modification onto proteins and nucleic acids to alter their structures and/or functions. Growing evidence support the importance of ADP-ribosylation and ADP-ribosylation-associated enzymes in aging and age-related diseases. In this review, we summarized ADP-ribosylation-associated proteins including ADP-ribosyl transferases, the ADP-ribosyl hydrolyses and ADP-ribose binding domains. Furthermore, we outlined the latest knowledge about regulation of ADP-ribosylation in the pathogenesis and progression of main aging-related diseases, organism aging and cellular senescence, and we also speculated the underlying mechanisms to better disclose this novel molecular network. Moreover, we discussed current issues and provided an outlook for future research, aiming to revealing the unknown bio-properties of ADP-ribosylation, and establishing a novel therapeutic perspective in aging-related diseases and health aging via targeting ADP-ribosylation.

From premature birth to premature kidney disease: does accelerated aging play a role?

As the limits of fetal viability have increased over the past 30 years, there has been a growing body of evidence supporting the idea that chronic disease should be taken into greater consideration in addition to survival after preterm birth. Accumulating evidence also suggests there is early onset of biologic aging after preterm birth. Similarly, chronic kidney disease (CKD) is also associated with a phenotype of advanced biologic age which exceeds chronologic age. Yet, significant knowledge gaps remain regarding the link between premature biologic age after preterm birth and kidney disease. This review summarizes the four broad pillars of aging, the evidence of premature aging following preterm birth, and in the setting of CKD. The aim is to provide additional plausible biologic mechanisms to explore the link between preterm birth and CKD. There is a need for more research to further elucidate the biologic mechanisms of the premature aging paradigm and kidney disease after preterm birth. Given the emerging research on therapies for premature aging, this paradigm could create pathways for prevention of advanced CKD.

Association between weight-adjusted-waist index and cognitive decline in US elderly participants

Objective

To investigate the association between the weight-adjusted-waist index (WWI) and cognitive decline in elderly Americans from 2011 to 2014.

Methods

A cross-sectional study was conducted on 2,762 elderly participants from the National Health and Nutrition Examination (NHANES) between 2011 and 2014. WWI was calculated by dividing waist circumference (cm) by the square root of body weight (kg). Participants assessed their cognitive functions using tests such as the DSST, AFT, and CERAD W-L. In this research, multiple logistic regression, HIA, limited cubic spline (RCS), and threshold effect analysis methods were utilized to explore the relationship between cognitive decline and WWI.

Results

The study involved 2,762 participants aged 60 years and older, comprising 1,353 males (49%) and 1,409 females (51%), with a median age of 69.3 years (standard deviation = 6.7). The analysis revealed that the risk of cognitive decline was positively associated with the WWI. Fully adjusted models indicated significant correlations with the CERAD W-L [odds ratio (OR) = 1.24, 95% confidence interval (CI) = 1.06-1.46, p < 0.008], AFT (OR = 1.27, 95% CI = 1.08-1.49, p = 0.003), and DSST (OR = 1.56, 95% CI = 1.29-1.9, p < 0.001). Subgroup analysis demonstrated a consistent relationship across different population settings except for gender (average of interactions, p > 0.05). A J-shaped relationship between WWI and low DSST scores was observed using multivariate restricted cubic spline (RCS) regression (P for non-linearity <0.05), with the curve steepening when WWI ≥ 12.21 cm/√kg. Additionally, the study found that WWI was more strongly associated with an increased risk of cognitive decline than other obesity indicators such as Body Mass Index (BMI), waist circumference (WC), and A Body Shape Index (ABSI).

Conclusion

Our data have shown a significant positive association between the WWI and a higher risk of cognitive decline in older Americans, with a J-shaped non-linear relationship between WWI and DSST. In addition, our findings indicate that WWI was associated with greater cognitive decline than other markers of obesity.

Renin-angiotensin system inhibitors positively impact on multiple aging regulatory pathways: Could they be used to protect against human aging?

The renin-angiotensin system (RAS)-a classical blood pressure regulator-largely contributes to healthy organ development and function. Besides, RAS activation promotes age-related changes and age-associated diseases, which are attenuated/abolished by RAS-blockade in several mammalian species. RAS-blockers also increase rodent lifespan. In previous work, we discussed how RAS-blockade downregulates mTOR and growth hormone/IGF-1 signaling, and stimulates AMPK activity (together with klotho, sirtuin, and vitamin D-receptor upregulation), and proposed that at least some of RAS-blockade's aging benefits are mediated through regulation of these intermediaries and their signaling to mitochondria. Here, we included RAS-blockade's impact on other aging regulatory pathways, that is, TGF-ß, NF-kB, PI3K, MAPK, PKC, Notch, and Wnt, all of which affect mitochondria. No direct evidence is available on RAS/RAS-blockade-aging regulatory pathway-mitochondria interactions. However, existing results allow to conjecture that RAS-blockers neutralize mitochondrial dysfunction by acting on the discussed pathways. The reviewed evidence led us to propose that the foundation is laid for conducting clinical trials aimed at testing whether angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB)-even at subclinical doses-offer the possibility to live longer and in better health. As ACEi and ARB are low cost and well-tolerated anti-hypertension therapies in use for over 35 years, investigating their administration to attenuate/prevent aging effects seems simple to implement.

A new histopathological phenomenon: Pancreatic islet cell loss in the elderly population

BACKGROUND

We observed the phenomenon of pancreatic islet cell loss (ICL) in our previous histopathological study. Multiple studies have reported that a decrease in β-cells is correlated with diabetes or chronic pancreatitis. Few studies have reported ICL in a healthy population.

METHODS

Thirty-three pancreatic tissue samples were obtained from cadavers (age: 65-104 years) who had never been diagnosed with any pancreatic diseases before death. The pancreatic body sections were used for an immunohistochemical study of pancreatic islet cells, and area calculations were performed using ImageJ to determine the degree of ICL and islet cell proportions.

RESULTS

The proportion of β-cells showed a downward trend as the degree of ICL increased (r=-0.414, P = 0.011), and the proportion of women with severe ICL was significantly higher than that of men with severe ICL (P = 0.016). The probability of severe ICL decreased with age in the population over 70 years of age (P = 0.069, linear correlation). Severe ICL may be associated with higher pancreatic intraepithelial neoplasia lesions (P = 0.059).

CONCLUSION

The phenomenon of ICL in the elderly population was mainly due to pancreatic β-cell reduction. It may be one of the direct causes of age-related diabetes.

Metabolic change in monocytes and postoperative morbidity after major abdominal surgery in elderly patients: A prospective cohort study

Background

Postoperative complications in aging patients remain a significant cause of increased costs, hospital length of stay, and patient distress. Although alterations in energy metabolism have been closely linked to aging process and surgery, it is still unclear whether metabolic changes during surgery is associated with postoperative complications in elderly patients. This study was conducted to investigate whether metabolic changes during surgery predicts postoperative complications in elderly patients.

Methods

We conducted a prospective single-center observational cohort study. 244 adults (aged ≥65 years) who were scheduled for elective major non-cardiac surgery were recruited. Blood samples for each patient were taken before and after surgery. All patients were randomly divided into two groups (122 in each group), then oxygen consumption rate (OCR) or extracellular acidification rate (ECAR) was measured on isolated monocytes in each group.

Results

14 of 110 (12.7%) patients went through OCR measurement and 15 of 122 patients (12.3%) went through ECAR measurement experienced moderate to severe complications. Overall, there was an intensification of glycolysis in monocytes after surgery. Among all variables, only the change (preoperative -postoperative) of glycolytic reserve (GR)/glycolysis (G) and GR/non-glycolytic acidification (NG) were predictors of moderate to severe complications (AUC = 0.70; 95% CI, 0.56-0.81; P = 0.019 and AUC = 0.67; 95% CI, 0.55-0.80; P = 0.031). Decreased postoperative GR/G were associated with worse postoperative complications (RR = 9.08; 95% CI, 1.23-66.81; P = 0.024).

Conclusions

Compared with mitochondria function, the change of glycolytic function in monocyte was more valuable in predicting postoperative complications after major abdominal surgery. Our study gave us a new insight into identifying patients at high risk in aging patients.

IgG is an aging factor that drives adipose tissue fibrosis and metabolic decline

Aging is underpinned by pronounced metabolic decline; however, the drivers remain obscure. Here, we report that IgG accumulates during aging, particularly in white adipose tissue (WAT), to impair adipose tissue function and metabolic health. Caloric restriction (CR) decreases IgG accumulation in WAT, whereas replenishing IgG counteracts CR's metabolic benefits. IgG activates macrophages via Ras signaling and consequently induces fibrosis in WAT through the TGF-β/SMAD pathway. Consistently, B cell null mice are protected from aging-associated WAT fibrosis, inflammation, and insulin resistance, unless exposed to IgG. Conditional ablation of the IgG recycling receptor, neonatal Fc receptor (FcRn), in macrophages prevents IgG accumulation in aging, resulting in prolonged healthspan and lifespan. Further, targeting FcRn by antisense oligonucleotide restores WAT integrity and metabolic health in aged mice. These findings pinpoint IgG as a hidden culprit in aging and enlighten a novel strategy to rejuvenate metabolic health.