Fat tissue, aging, and cellular senescence

The brain-white adipose tissue axis may play a crucial role in diabetes mellitus: a metabolic network analysis using total-body PET/CT imaging

PURPOSE

This study aims to construct an individualized glucose metabolism network using total-body 18F-FDG PET imaging, which provides a comprehensive view of glucose metabolism across various organs, to explore the role of inter-organ interactions in Diabetes Mellitus (DM).

METHODS

In this study, we constructed covariance metabolic networks using static total-body PET images, normalized by lean body mass, from 36 patients with DM (DM group) and 36 age- and sex-matched healthy controls (HC group). Differences in network properties between the DM and HC groups were evaluated at both group and individual levels. In addition, correlation analysis was performed to explore the relationship between network properties and baseline clinical data in the DM subjects.

RESULTS

We observed that the same edges in the first three edges with the largest values were brain-subcutaneous adipose tissue (SAT) and brain-visceral adipose tissue (VAT) at both group and individual levels. There was a positive correlation between the brain-VAT and BMI and there was a negative correlation between the brain-SAT and age. The most perturbed organ was the brain at both group and individual levels, and there was a positive correlation between the strength of abnormality of brain and age.

CONCLUSION

This study successfully used static total-body PET imaging to construct individualized glucose metabolism networks for patients with DM, identifying the brain-VAT and brain-SAT as the most significantly altered edge and the brain as the most affected organ. These findings provide novel insights into the role of the brain-white adipose tissue axis in glucose metabolism in DM.

Early Pregnancy Plasma Per- and Polyfluoroalkyl Substances (PFAS) and Maternal Midlife Adiposity

CONTEXT

Evidence suggests that exposure to per- and polyfluoroalkyl substances (PFAS) increases the risk of developing cardiometabolic disease risk factors. Limited research has evaluated associations between PFAS, assessed during pregnancy, a sensitive window for maternal endocrine effects, and long-term maternal adiposity.

OBJECTIVE

Estimate associations of early pregnancy measures of individual PFAS, and PFAS mixtures, with maternal adiposity in midlife.

METHODS

We studied 547 Project Viva participants with measures of early pregnancy (mean gestation 10.0 weeks; mean age 32.5 years) plasma concentrations of 6 PFAS and midlife adiposity outcomes (mean follow-up 17.7 years; mean age 50.7 years), including weight, waist circumference (WC), trunk fat mass (TFM), and total body fat mass (TBFM). We used linear regression and Bayesian Kernel Machine Regression (BKMR).

RESULTS

Linear regression estimated higher midlife weight per doubling of perfluorooctane sulfonate (PFOS) (3.8 kg [95% CI: 1.6, 5.9]) and 2-(N-ethyl-perfluorooctane sulfonamido) acetate (2.3 kg [95% CI: 0.9, 3.7]). BKMR analyses of single PFAS plasma concentrations (comparing the 25th percentile concentration to the 75th percentile) showed a positive association between PFOS and midlife adiposity (weight: 7.7 kg [95% CI: 4.0, 11.5]; TFM: 1.2 kg [95% CI: 0.0, 2.3]; TBFM: 3.0 kg [95% CI: 0.8, 5.2]), but inverse associations with perfluorononanoate (weight: -6.0 kg [95% CI: -8.5, -3.5]; WC: -1.8 cm [95% CI: -3.2, -0.3]; TFM: -0.8 kg [95% CI: -1.5, -0.1]; TBFM: -1.4 kg [95% CI: -2.7, -0.3]) and perfluorohexane sulfonate (TFM: -0.8 kg [95% CI: -1.5, -0.1]; TBFM: -1.4 kg [95% CI: -2.6, -0.2]). No associations were observed with the overall PFAS mixture.

CONCLUSION

Select PFAS, assessed in pregnancy, may differentially affect maternal midlife adiposity, influencing later-life maternal cardiometabolic health.

Aging and metabolic dysfunction-associated steatotic liver disease: a bidirectional relationship

In recent years, aging and cellular senescence have triggered an increased interest in corresponding research fields. Evidence shows that the complex aging process is involved in the development of many chronic liver diseases, such as metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). In fact, aging has a tremendous effect on the liver, leading to a gradual decline in the metabolism, detoxification and immune functions of the liver, which in turn increases the risk of liver disease. These changes can be based on the aging of liver cells (hepatocytes, liver sinusoidal endothelial cells, hepatic stellate cells, and Kupffer cells). Similarly, patients with liver diseases exhibit increases in the aging phenotype and aging cells, often manifesting as faster physical functional decline, which is closely related to the promoting effect of liver disease on aging. This review summarizes the interplay between MASLD/MASH development and aging, aiming to reveal the complex relationships that exacerbate one another. Moreover, the corresponding schemes for delaying aging or treating diseases are discussed to provide a basis for the development of effective prevention and treatment strategies in the future.

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.

Senescence profiling of monoclonal gammopathies reveals paracrine senescence as a crucial defense against disease progression

Multiple myeloma (MM) is a plasma cell (PC) malignancy that is preceded by monoclonal gammopathy of undetermined significance (MGUS) and/or smoldering multiple myeloma (SMM). MGUS and SMM PCs exhibit the same primary oncogenic abnormalities as MM but lack the end-organ damage that defines proliferative disease, suggesting that clonal PCs in these precursor conditions could exhibit senescence or senescence-like growth arrest. Herein we identified monoclonal gammopathy patient-derived PCs that exhibit senescence features and found that senescent PCs were significantly increased in MGUS patients compared to SMM or MM. Spatial analysis of senescent PCs in stable MGUS and SMM patient biopsies demonstrated the activation of local paracrine senescence in the bone marrow microenvironment. Stable MGUS and SMM patients also exhibited disease-specific senescence-associated secretory phenotype (SASP) signatures that significantly correlated with PC burden and clonal antibody. In contrast, progressing MGUS, SMM, and new MM patients lacked local paracrine senescence responses and robust activation of disease specific SASP signatures. Overall, these data suggest that failure to activate tumor-specific paracrine senescence responses is key to disease progression in monoclonal gammopathies.

DNA damage in proximal tubules triggers systemic metabolic dysfunction through epigenetically altered macrophages

DNA damage repair is a critical physiological process closely linked to aging. The accumulation of DNA damage in renal proximal tubular epithelial cells (PTEC) is related to a decline in kidney function. Here, we report that DNA double-strand breaks in PTECs lead to systemic metabolic dysfunction, including weight loss, reduced fat mass, impaired glucose tolerance with mitochondrial dysfunction, and increased inflammation in adipose tissues and the liver. Single-cell RNA sequencing analysis reveals expansion of CD11c+ Ccr2+ macrophages in the kidney cortex, liver, and adipose tissues and Ly6Chi monocytes in peripheral blood. DNA damage in PTECs is associated with hypomethylation of macrophage activation genes, including Gasdermin D, in peripheral blood cells, which is linked to reduced DNA methylation at KLF9-binding motifs. Macrophage depletion ameliorates metabolic abnormalities. These findings highlight the impact of kidney DNA damage on systemic metabolic homeostasis, revealing a kidney-blood-metabolism axis mediated by epigenetic changes in macrophages.

Distinct adipose progenitor cells emerging with age drive active adipogenesis

Starting at middle age, adults often suffer from visceral adiposity and associated adverse metabolic disorders. Lineage tracing in mice revealed that adipose progenitor cells (APCs) in visceral fat undergo extensive adipogenesis during middle age. Thus, despite the low turnover rate of adipocytes in young adults, adipogenesis is unlocked during middle age. Transplantations quantitatively showed that APCs in middle-aged mice exhibited high adipogenic capacity cell-autonomously. Single-cell RNA sequencing identified a distinct APC population, the committed preadipocyte, age-enriched (CP-A), emerging at this age. CP-As demonstrated elevated proliferation and adipogenesis activity. Pharmacological and genetic manipulations indicated that leukemia inhibitory factor receptor signaling was indispensable for CP-A adipogenesis and visceral fat expansion. These findings uncover a fundamental mechanism of age-dependent adipose remodeling, offering critical insights into age-related metabolic diseases.

The Relationship between Visceral Fat Accumulation and Risk of Cardiometabolic Multimorbidity: The Roles of Accelerated Biological Aging

OBJECTIVES

To investigate the association between visceral fat accumulation and the risk of cardiometabolic multimorbidity (CMM) and the potential roles of accelerated biological aging in this relationship.

METHODS

Using data from the UK Biobank, a nationwide cohort study was conducted using the available baseline body roundness index (BRI) measurement. Biological aging was assessed using the Klemera-Doubal method for biological age and the phenotypic age algorithms. The association between the BRI and CMM was estimated using the Cox proportional hazards regression model, while the roles of biological aging were examined through interaction and mediation analyses.

RESULTS

During a median follow-up of 14.52 years, 6156 cases of CMM were identified. A significant association was observed between the BRI and CMM. The hazard ratio (HR) for CMM was 3.72 (95% confidence interval [CI]: 3.35-4.13) for individuals in the highest quartile compared with those in the lowest quartile of the BRI. More importantly, the BRI (AUC, 0.701; 95% CI, 0.694-0.707) demonstrated superior predictive performance relative to body mass index (AUC, 0.657; 95% CI, 0.650-0.664). Furthermore, the BRI exhibited additive interactions with accelerated biological aging on the risk of CMM, and accelerated biological aging partially mediated the association between the BRI and CMM.

CONCLUSIONS

These findings provide evidence for the application of the BRI as a novel and readily accessible screening tool associated with CMM, suggesting that the effective management of visceral fat and biological aging deceleration may hold promise for reducing CMM risk.

Metabolic interplays between the tumour and the host shape the tumour macroenvironment

Metabolic reprogramming of cancer cells and the tumour microenvironment are pivotal characteristics of cancers, and studying these processes offer insights and avenues for cancer diagnostics and therapeutics. Recent advancements have underscored the impact of host systemic features, termed macroenvironment, on facilitating cancer progression. During tumorigenesis, these inherent features of the host, such as germline genetics, immune profile and the metabolic status, influence how the body responds to cancer. In parallel, as cancer grows, it induces systemic effects beyond the primary tumour site and affects the macroenvironment, for example, through inflammation, the metabolic end-stage syndrome of cachexia, and metabolic dysregulation. Therefore, understanding the intricate metabolic interplay between the tumour and the host is a growing frontier in advancing cancer diagnosis and therapy. In this Review, we explore the specific contribution of the metabolic fitness of the host to cancer initiation, progression and response to therapy. We then delineate the complex metabolic crosstalk between the tumour, the microenvironment and the host, which promotes disease progression to metastasis and cachexia. The metabolic relationships among the host, cancer pathogenesis and the consequent responsive systemic manifestations during cancer progression provide new perspectives for mechanistic cancer therapy and improved management of patients with cancer.

The Effects of Concurrent Training Versus Aerobic or Resistance Training Alone on Body Composition in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis

Introduction and Aim: The beneficial effects of aerobic training (AT) on preventing excess fat mass, and of resistance training (RT) on skeletal muscle adaptation, are well established. However, the effects of concurrent training (CT) compared to AT or RT alone on body composition in middle-aged and older adults are less understood, and therefore, the focus of this meta-analysis. Methods: Three databases, including PubMed, Web of Science, and Scopus, were searched from inception to March 2024. Randomized trials were included if they compared CT versus either AT or RT, and included body composition measures such as fat mass, body fat percentage, waist circumference, visceral fat mass, lean body mass (LBM), muscle mass/volume, or muscle or muscle fiber cross-sectional area (CSA), in middle-aged (50 to <65 years) and older adults (≥65 years). Weighted mean differences (WMD) or standardized mean differences (SMD) and 95% confidence intervals (CIs) were calculated using random effects models. Results: A total of 53 studies involving 2873 participants were included. Overall, CT increased body weight and LBM significantly more, trending toward significantly larger increases in muscle mass and CSA, compared with AT alone. However, there were no significant differences between CT and RT alone, for body weight, BMI, body fat percentage, fat mass, waist circumference, or visceral fat mass. Conclusions: CT is as effective as AT for decreasing body fat measures and as effective as RT for increasing muscle mass in middle-aged and older adults, and it should be recommended accordingly.

Sauver J, Fielding RA, Atkinson E, White TA, McGree M, Weston S, LeBrasseur NK. The Influence of Body Mass Index on Biomarkers of Cellular Senescence in Older Adults

Obesity accelerates the onset and progression of age-related conditions. In preclinical models, obesity drives cellular senescence, a cell fate that compromises tissue health and function, in part through a robust and diverse secretome. In humans, components of the secretome have been used as senescence biomarkers that are predictive of age-related disease, disability, and mortality. Here, using biospecimens and clinical data from two large and independent cohorts of older adults, we tested the hypothesis that the circulating concentrations of senescence biomarkers are influenced by body mass index. After adjusting for age, sex, and race, we observed significant increases in activin A, Fas, MDC, PAI1, PARC, TNFR1, and VEGFA, and a significant decrease in RAGE, from normal weight, to overweight, to obesity body mass index categories by linear regression in both cohorts (all p < .05). These results highlight the influence of body mass index on circulating concentrations of senescence biomarkers.

Cellular senescence and PAPP-A

Cellular senescence and its accompanying secretome have major impact on growth and aging of mammalian organisms. A novel protease, PAPP-A, regulates the bioavailability of an important growth factor, insulin-like growth factor (IGF)-I, and has major impact on growth and aging. This short review will explore a new perspective of cellular senescence and PAPP-A.

Systemic immune-inflammation index mediates the association between abdominal obesity and serum klotho levels

The weight-adjusted waist index (WWI) has emerged as a reliable indicator of abdominal obesity. α-Klotho, a transmembrane protein, functions as a suppressor of aging. However, the relationship between these two factors remains underexplored. This study aims to investigate the association between WWI and serum α-Klotho levels in middle-aged and elderly Americans, with a focus on exploring the potential mediating role of the systemic immune inflammation index (SII). A cross-sectional study was conducted using data from 6997 middle-aged and elderly Americans participating in the National Health and Nutrition Examination Surveys (NHANES) between 2011 and 2016. Multiple linear regression analysis was employed to assess the relationship between WWI and serum α-Klotho concentrations. Additionally, mediation analysis was performed to investigate the mediating effect of SII on the relationships. Our analysis revealed a significant negative correlation between WWI and serum α-Klotho levels in the survey-weighted multiple linear regression models (adjusted percent change: -7.79; 95% CI: -10.15, -5.37). Mediation analysis demonstrated that the association between WWI and α-Klotho levels was partially mediated by SII (adjusted percent change: -0.88; 95% CI: -1.24, -0.45), with the proportion of mediation amounting to 11.6%. Further age-stratified results showed that the mediating role of SII was more pronounced among individuals aged ≥ 60 years, exhibiting a mediating effect of 26.3%, in contrast to 4.2% for those < 60 years. The findings suggest that WWI is inversely associated with serum α-Klotho concentrations and that this association is partially mediated by SII, especially in older people.

In Vitro Treatment with Metformin Significantly Reduces Senescent B Cells Present in the Adipose Tissue of People with Obesity

BACKGROUND

Our previous work has shown that senescent B cells accumulate in the human adipose tissue (AT) of people with obesity, where they express transcripts for markers associated with the senescence-associated secretory phenotype (SASP) and secrete multiple inflammatory mediators. These functions of AT-derived B cells are metabolically supported.

OBJECTIVES

To show that Metformin (MET), a widely used hypoglycemic and antidiabetic drug, is able at least in vitro to decrease frequencies, secretory profile, and metabolic requirements of senescent B cells isolated from the AT of people with obesity.

METHODS

We recruited adult females with obesity (n = 8, age 40 ± 2 y, BMI range: 33-42) undergoing breast reduction surgery, who donated their discarded subcutaneous AT. B cells from stromal vascular fractions isolated after collagenase digestion of the AT were evaluated after in vitro incubation with MET (1 mM × 106 B cells) or with a control medium without MET for the following measures: expression of transcripts for SASP-associated markers (p16INK4a and p21CIP1/WAF1) measured by quantitative polymerase chain reaction (qPCR); secretion of inflammatory cytokines (TNF-α, IL-6, IFN-γ and IL-17A) measured by a Cytometric Bead Array); metabolic characteristics as identified by a glycolytic test and Seahorse technology, and by the expression of transcripts for glucose transporters and metabolic enzymes involved in glucose metabolic pathways, measured by qPCR. To examine differences between MET-treated compared with untreated groups, paired Student's t tests (two-tailed) were employed.

RESULTS

MET in vitro was able to reduce frequencies and numbers of senescent B cells, as identified by staining with β-galactosidase, as well as the secretion of inflammatory cytokines, the expression of transcripts for SASP, and metabolic markers that support intrinsic B cell inflammation.

CONCLUSIONS

Our results provide evidence to support the beneficial effects of MET in reducing AT-related inflammation through its effects on senescent B cells.

Poor muscle quality: A hidden and detrimental health condition in obesity

Poor muscle quality (MQ) is a hidden health condition in obesity, commonly disregarded and underdiagnosed, associated with poor health-related outcomes. This narrative review provides an in-depth exploration of MQ in obesity, including definitions, available assessment methods and challenges, pathophysiology, association with health outcomes, and potential interventions. MQ is a broad term that can include imaging, histological, functional, or metabolic assessments, evaluating beyond muscle quantity. MQ assessment is highly heterogeneous and requires further standardization. Common definitions of MQ include 1) muscle-specific strength (or functional MQ), the ratio between muscle strength and muscle quantity, and 2) muscle composition (or morphological MQ), mainly evaluating muscle fat infiltration. An individual with obesity might still have normal or higher muscle quantity despite having poor MQ, and techniques for direct measurements are needed. However, the use of body composition and physical function assessments is still limited in clinical practice. Thus, more accessible techniques for assessing strength, muscle mass, and composition should be further explored. Obesity leads to adipocyte dysfunction, generating a low-grade chronic inflammatory state, which leads to mitochondrial dysfunction. Adipocyte and mitochondrial dysfunction result in metabolic dysfunction manifesting clinically as insulin resistance, dyslipidemia, and fat infiltration into organs such as muscle, which in excess is termed myosteatosis. Myosteatosis decreases muscle cell function and insulin sensitivity, creating a vicious cycle of inflammation and metabolic derangements. Myosteatosis increases the risk of poor muscle function, systemic metabolic complications, and mortality, presenting prognostic potential. Interventions shown to improve MQ include nutrition, physical activity/exercise, pharmacology, and metabolic and bariatric surgery.

Sarcopenia and cachexia: molecular mechanisms and therapeutic interventions

Sarcopenia is defined as a muscle-wasting syndrome that occurs with accelerated aging, while cachexia is a severe wasting syndrome associated with conditions such as cancer and immunodeficiency disorders, which cannot be fully addressed through conventional nutritional supplementation. Sarcopenia can be considered a component of cachexia, with the bidirectional interplay between adipose tissue and skeletal muscle potentially serving as a molecular mechanism for both conditions. However, the underlying mechanisms differ. Recognizing the interplay and distinctions between these disorders is essential for advancing both basic and translational research in this area, enhancing diagnostic accuracy and ultimately achieving effective therapeutic solutions for affected patients. This review discusses the muscle microenvironment's changes contributing to these conditions, recent therapeutic approaches like lifestyle modifications, small molecules, and nutritional interventions, and emerging strategies such as gene editing, stem cell therapy, and gut microbiome modulation. We also address the challenges and opportunities of multimodal interventions, aiming to provide insights into the pathogenesis and molecular mechanisms of sarcopenia and cachexia, ultimately aiding in innovative strategy development and improved treatments.

Role of Dardarin and Isthmin-1 in the Protective Effect of Hydroxytyrosol Against Corn Syrup-Induced Liver Damage

INTRODUCTION

In this study, it was investigated whether dardarin (LRRK2) and isthmin-1 (ISM1) play a role in the protective effect of hydroxytyrosol (HT) used to prevent liver damage caused by corn syrup in rats.

METHODS

Rats were divided into four groups with six in each group: 1) control, 2) HT, 3) corn syrup, and 4) corn syrup + HT. Rats were given water containing 30% corn syrup for six weeks. At the same time, HT-containing liquid was given orally at 4 ml/kg/day, alone and together with corn syrup for six weeks. The weights of the rats were measured every week. LRRK2 and ISM1 molecules in liver tissue were evaluated by histopathological methods. Biochemical parameters were also examined with the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

It was found that weight gain was less in rats receiving HT than in those consuming corn syrup. The increase in cholesterol, triglyceride, and liver enzyme levels because of corn syrup consumption decreased with HT consumption. As a result of histopathological analysis, it was observed that the increase in LRRK2 and ISM1 levels observed in the liver tissue in the corn syrup-administered group decreased when HT was administered together with corn syrup. In addition, it was determined that the increase in sinusoidal expansion and hepatocyte necrosis observed in the liver tissue as a result of corn syrup application decreased as a result of the application of HT together with corn syrup.

CONCLUSION

The protective effect of HT against the damage caused by corn syrup in the liver has been demonstrated once again; however, LRRK2 and ISM1 are thought to contribute to this issue.

Establishment of immortalized porcine intramuscular preadipocytes for the study of lipid metabolism

Intramuscular adipose tissue is associated with an increased risk for the development of metabolic syndrome. A cellular model of adipogenesis in muscular tissues would be an invaluable tool for studying regulatory factors in this important process. Cellular stress can impact the homeostasis of various metabolic pathways, including lipid metabolism. In this study, a porcine intramuscular preadipocyte cell line was established, which displayed mature adipocyte attributes such as lipid accumulation and increased expression of adipogenic gene markers. Since it is well established that endoplasmic reticulum (ER) and Golgi stress impact adipogenesis, we sought to investigate the effects of ER/Golgi stress and an associated protein, CREB3, in this cell line model. We found that this novel model maintains robust adipogenic capabilities, and that ER stress can negatively affect adipogenic markers. Overall, these findings demonstrate the strength of the new cell model for studying adipogenesis, and highlight the impact of ER stress on lipid metabolism.

Alterations in the transcriptome and microRNAs of adipose-derived mesenchymal stem cells from different sites in rats during aging

Aging is an intricate and gradual process characterized by tissue and cellular dysfunction. Adipose-derived mesenchymal stem cells (ADMSCs) experience a functional decline as part of systemic aging. However, the alterations in ADMSCs across various anatomical sites throughout an individual's lifespan remain unclear. To shed light on these changes, we collected white adipose tissue and brown adipose tissue samples from the epididymis, perirenal, inguinal, and scapular regions of young, adult, and aged rats and subsequently isolated ADMSCs for RNA sequencing. As aging progressed, we observed a reduction in the number of ADMSCs at all anatomical sites. Marker genes of ADMSCs from different sites were identified. Aging triggered notable activation of inflammatory and immune responses while diminishing the ADMSC differentiation capacity and ability to maintain a normal tissue morphology. Furthermore, miR-195-5p and miR-497-3p, which promoted cell senescence and apoptosis while inhibiting proliferation and differentiation, were positively correlated with aging. These findings increase our understanding of ADMSC senescence and underscore the unique physiological changes and functions of ADMSCs across different anatomical sites during aging.NEW & NOTEWORTHY Dynamic changes in mRNAs and miRNAs of ADMSCs during aging are shown. As aging progressed, we observed a reduction in the number of ADMSCs at all anatomical sites. Aging leads to the activation of inflammatory and cellular dysfunction. miR-195-5p and miR-497-3p are positively correlated with aging, which promoted cell senescence and apoptosis while inhibiting proliferation and differentiation. ADMSCs associated with different anatomical sites have site-specific markers.

Senescent cell depletion alleviates obesity-related metabolic and cardiac disorders

Obesity is a major contributor to metabolic and cardiovascular disease. Although senescent cells have been shown to accumulate in adipose tissue, the role of senescence in obesity-induced metabolic disorders and in cardiac dysfunction is not yet clear; therefore, the therapeutic potential of managing senescence in obesity-related metabolic and cardiac disorders remains to be fully defined.

OBJECTIVE

We investigated the beneficial effects of a senolytic cocktail (dasatinib and quercetin) on senescence and its influence on obesity-related parameters.

METHODS AND RESULTS

We found that the increase in body weight and adiposity, glucose intolerance, insulin resistance, dyslipidemia, hyperleptinemia, and hepatic disorders which were induced by an obesogenic diet were alleviated by senolytic cocktail treatment in mice. Treatment with senolytic compounds eliminated senescent cells, counteracting the activation of the senescence program and DNA damage in white adipose tissue (WAT) observed with an obesogenic diet. Moreover, the senolytic cocktail prevented the brown adipose tissue (BAT) whitening and increased the expression of the thermogenic gene profile in BAT and pWAT. In the hearts of obese mice, senolytic combination abolished myocardial maladaptation, reducing the senescence-associated secretory phenotype (SASP) and DNA damage, repressing cardiac hypertrophy, and improving diastolic dysfunction. Additionally, we showed that treatment with the senolytic cocktail corrected gene expression programs associated with fatty acid metabolism, oxidative phosphorylation, the P53 pathway, and DNA repair, which were all downregulated in obese mice.

CONCLUSIONS

Collectively, these data suggest that a senolytic cocktail can prevent the activation of the senescence program in the heart and WAT and activate the thermogenic program in BAT. Our results suggest that targeting senescent cells may be a novel therapeutic strategy for alleviating obesity-related metabolic and cardiac disorders.

Pharmacological inactivation of a non-canonical gp130 signaling arm attenuates chronic systemic inflammation and multimorbidity induced by a high-fat diet

Interleukin-6 (IL-6) is a major pro-inflammatory cytokine that demonstrates a robust correlation with age and body mass index (BMI) as part of the senescence-associated secretory phenotype. IL-6 cytokines also play a crucial role in metabolic homeostasis and regenerative processes primarily via the canonical STAT3 pathway. Thus, selective modulation of IL-6 signaling may offer a unique opportunity for therapeutic interventions. Our recent studies identified a novel non-canonical signaling pathway that involves prolonged activation of SRC family of kinases (SFKs) by IL-6/gp130, where genetic or pharmacological inhibition of this pathway was protective in several acute injury models. This study was designed to assess the effect of a small molecule (R159) that inhibits the non-canonical signaling in a mouse model of multimorbidity induced by chronic inflammation. Aged mice were fed a high-fat diet (HFD) to exacerbate chronic inflammation and inflammaging-related conditions, and R159 significantly decreased systemic inflammatory responses in adipose tissue and liver. R159 was protective against trabecular bone and articular cartilage loss and markedly prevented neurogenesis decline. Moreover, R159 reduced weight gain induced by HFD and increased physical activity levels. These findings suggest that selective pharmacological inhibition of SFK signaling downstream of IL6/gp130 offers a promising strategy to alleviate systemic chronic inflammation and relevant multimorbidity.

Molecular and Cellular Mechanisms of Immunosenescence: Modulation Through Interventions and Lifestyle Changes

Immunosenescence, the age-related decline in immune function, is a complex biological process with profound implications for health and longevity. This phenomenon, characterized by alterations in both innate and adaptive immunity, increases susceptibility to infections, reduces vaccine efficacy, and contributes to the development of age-related diseases. At the cellular level, immunosenescence manifests as decreased production of naive T and B cells, accumulation of memory and senescent cells, thymic involution, and dysregulated cytokine production. Recent advances in molecular biology have shed light on the underlying mechanisms of immunosenescence, including telomere attrition, epigenetic alterations, mitochondrial dysfunction, and changes in key signaling pathways such as NF-κB and mTOR. These molecular changes lead to functional impairments in various immune cell types, altering their proliferative capacity, differentiation, and effector functions. Emerging research suggests that lifestyle factors may modulate the rate and extent of immunosenescence at both cellular and molecular levels. Physical activity, nutrition, stress management, and sleep patterns have been shown to influence immune cell function, inflammatory markers, and oxidative stress in older adults. This review provides a comprehensive analysis of the molecular and cellular mechanisms underlying immunosenescence and explores how lifestyle interventions may impact these processes. We will examine the current understanding of immunosenescence at the genomic, epigenomic, and proteomic levels, and discuss how various lifestyle factors can potentially mitigate or partially reverse aspects of immune aging. By integrating recent findings from immunology, gerontology, and molecular biology, we aim to elucidate the intricate interplay between lifestyle and immune aging at the molecular level, potentially informing future strategies for maintaining immune competence in aging populations.

Aging Parameters of the Accelerated Aging Procedure through D-Galactose Induction

Background and Objectives

Intraperitoneal injection (i.p.) of D-galactose (D-gal) accelerates aging and develops aging models. A low dose of long-term use and a high dose of short-term use of D-gal can induce natural aging in mice, like brain, cardiac, liver, renal, and skin aging, and erectile dysfunction. Our research aims to determine whether a high dose of short-term use of D-gal. i.p. in rats can induce natural aging and affect the following parameters: body weight (BW), Superoxide Dismutase (SOD), Vascular endothelial growth factor (VEGF), C-reactive protein (CRP), and myostatin.

Methods

A daily D-gal i.p. dose of 300 mg/ml/kg for seven days was carried out to induce aging parameters in the rats. After seven days, the body and gastrocnemius circumference of the rats were weighed, and biochemical analysis for SOD, VEGF, CRP, and myostatin in the blood plasma was done.

Results

The data obtained were analyzed using nonparametric statistics Friedman test and Mann-Whitney test. After the seven day-intervention, both the control (NaCl 0.9% i.p.) and the high dose of short-term use of D-gal i.p. groups showed no significant difference in the body weight and gastrocnemius circumference. However, D-gal administration could increase the blood plasma level of SOD, VEGF, CRP, and myostatin.

Conclusion

We conclude that a high dose of short-term intraperitoneal D-galactose can be administrated to induce aging in rat models. The SOD, VEGF, CRP and myostatin can be used as aging parameters.

The Emerging Role of p21 in Diabetes and Related Metabolic Disorders

In the context of cell cycle inhibition, anti-proliferation, and the dysregulation observed in certain cancer pathologies, the protein p21 assumes a pivotal role. p21 links DNA damage responses to cellular processes such as apoptosis, senescence, and cell cycle arrest, primarily functioning as a regulator of the cell cycle. However, accumulating empirical evidence suggests that p21 is both directly and indirectly linked to a number of different metabolic processes. Intriguingly, recent investigations indicate that p21 significantly contributes to the pathogenesis of diabetes. In this review, we present a comprehensive evaluation of the scientific literature regarding the involvement of p21 in metabolic processes, diabetes etiology, pancreatic function, glucose homeostasis, and insulin resistance. Furthermore, we provide an encapsulated overview of therapies that target p21 to alleviate metabolic disorders. A deeper understanding of the complex interrelationship between p21 and diabetes holds promise for informing current and future therapeutic strategies to address this rapidly escalating health crisis.

Effects of high fat diet on metabolic health vary by age of menopause onset

Menopause accelerates metabolic dysfunction, including (pre-)diabetes, obesity and visceral adiposity. However, the effects of endocrine vs. chronological aging in this progression are poorly understood. We hypothesized that menopause, especially in the context of middle-age, would exacerbate the metabolic effects of a high fat diet. Using young-adult and middle-aged C57BL/6J female mice, we modeled diet-induced obesity via chronic administration of high fat (HF) diet vs. control diet. We modeled peri-menopause/menopause via injections of 4-vinylcyclohexene diepoxide, which accelerates ovarian failure vs. vehicle. We performed glucose tolerance tests 2.5 and 7 months after diet onset, during the peri-menopausal and menopausal phases, respectively. Peri-menopause increased the severity of glucose intolerance and weight gain in middle-aged, HF-fed mice. Menopause increased weight gain in all mice regardless of age and diet, while chronological aging drove changes in adipose tissue distribution towards more visceral vs. subcutaneous adiposity. These data are in line with clinical data showing that post-menopausal women are more susceptible to metabolic dysfunction and suggest that greater chronological age exacerbates the effects of endocrine aging (menopause). This work highlights the importance of considering both chronological and endocrine aging in studies of metabolic health.

Sarcopenic Obesity: A Comprehensive Approach for Postmenopausal Women

Sarcopenic obesity, characterized by the concurrent presence of muscle loss and obesity, poses significant health challenges, especially in the elderly. This review explores the impact of sarcopenic obesity on disability, metabolic health, comorbidities, and potential management strategies. With the aging global population, the prevalence of sarcopenic obesity is expected to increase, necessitating a comprehensive management approach. Early screening, prevention, and ongoing research on its underlying mechanisms and therapeutic options are crucial for promoting healthy aging.

Quality Characteristics Changes of the Fat Portion of Chinese Bacon During Processing Based on Physicochemical Properties and Microstructure Studies

In order to elucidate the development of quality properties in the fat portion of Chinese bacon during low-temperature smoking (LTS), raw pork was cured for five days, followed by infusion with smoked liquid and a subsequent ten-day smoking period characterized by alternating high and low-temperature conditions. The physicochemical characteristics and microstructures of the fat portion of the Chinese bacon were examined at three stages: the raw meat stage (Control), the curing stage (C3d and C5d), and the smoking stage (S5d and S10d). The results showed that LTS increased the hardness, transparency, and b* value of bacon fat. The increased contents of neutral lipids and free fatty acids, increased activities of neutral lipase and lipoxygenase, and increased peroxide and thiobarbituric acid reactive substance value indicated significant lipolysis and lipid oxidation of bacon fat during LTS. After the treatment, a decreased melting point and increased β'- and β-type fat crystal formation were observed in the fat portion. Moreover, the treatment led to disruption of the adipocyte membrane structure. Therefore, the destruction of adipocytes after lipolysis and lipid oxidation during low-temperature smoking treatment might contribute to the development of quality properties of bacon fat portions. Precise control of temperature and time enhances the stability of the fat portion of bacon, thereby improving quality characteristics such as texture and appearance.

Body roundness index and cognitive function in older adults: a nationwide perspective

Background

Obesity negatively impacts cognitive function. However, the correlation between the body roundness index (BRI) and cognitive performance remains inadequately explored.

Methods

This study used data from the National Health and Nutrition Examination Survey (NHANES) collected from 2011 to 2014 to examine the correlation between BRI and cognitive function in individuals aged 65 and older. Models of multiple linear regression were used to investigate the relationship between BRI and cognitive performance. Additionally, smoothed curve fittings explored potential non-linear associations. Interaction tests and subgroup analyses were also performed.

Results

One thousand eight hundred seventy participants were taken into account, revealing an important negative relationship between BRI levels and cognitive performance. In the fully adjusted model, elevated BRI was substantially correlated with lower Digit Symbol Substitution Test (DSST) scores (β = -0.34, 95% CI = -0.64 to -0.05, p = 0.023), indicating that the higher BRI values are linked to worse cognitive performance. Sex differences were observed, with males showing a stronger negative association (p for interaction = 0.040).

Conclusion

Elevated BRI is related to worse cognitive function in the elderly population.

Similarities in B Cell Defects between Aging and Obesity

The aging population is increasing worldwide, and there is also an increase in the aging population living with overweight and obesity, due to changes in lifestyle and in dietary patterns that elderly individuals experience later in life. Both aging and obesity are conditions of accelerated metabolic dysfunction and dysregulated immune responses. In this review, we summarize published findings showing that obesity induces changes in humoral immunity similar to those induced by aging and that the age-associated B cell defects are mainly due to metabolic changes. We discuss the role of the obese adipose tissue in inducing dysfunctional humoral responses and autoimmune Ab secretion.

Prevalence of disability and associated functional limitations among older adults in Brazil

INTRODUCTION

Disabilities are a serious public health, social and human rights issue. Few studies address the relationship between disabilities and functioning among older adults. The study aimed to estimate the prevalence of disability and its' association with comorbidities and functional limitations in Brazilian elderly individuals.

METHODS

Data from the National Health Survey-PNS 2019 was used. Prevalence rates with its corresponding 95% confidence intervals (CI) were estimated for variables of interest. Chi-squared tests and multiple logistic regression were conducted to investigate associations and estimate crude and adjusted odds ratios (OR) using Stata 17.0 software. The critical value (p<0.05) was considered.

RESULTS

The overall prevalence of disability was 58.3% (95% CI 57.2-59.4). Moderate/severe disabilities accounted for 24.1 (95% CI 23.1-25.1) and was high among elderly people females (27.9%, 95% CI 26.5-29.3), unemployed (28.4%, 95% CI 27.3-29.6), with an income of up to one minimum wage (30.6%, 95% CI 29.1-32.2), lower education (28.7%, 95% CI 27.5-29.9) and not married (28.5%, 95% CI 27.1-29.9). Crude odds ratios of having functional limitations were 4.5 times higher among individuals with three or more comorbidities, and 32.5 times higher among those with two or more disabilities, compared to those without these conditions.

CONCLUSION

Having a disability is an important predictor of functional limitations, especially among women, and people with lower income and education. To address this problem, public health policies such as encouraging physical activity among the elderly in Brazil should be implemented.

Immunosenescence in digestive system cancers: Mechanisms, research advances, and therapeutic strategies

Increasing lifespans and external environmental factors have contributed to the increase of age-related diseases, particularly cancer. A decrease in immune surveillance and clearance of cancer cells is the result of immunosenescence, which involves the remodeling of immune organs, the changes and functional decline of immune cell subsets, in association with systemic low-grade chronic inflammation. Stem cells aging in bone marrow and thymic involution are the most important causes of immunosenescence. Senescent cancer cells promote the differentiation, recruitment, and functional upregulation of immune-suppressive cell subsets e.g. regulatory T cells (Tregs), myeloid-derived suppressor cell (MDSC), tumor-associated macrophages (TAMS) through senescence-associated secretory phenotype (SASP) further exacerbating the immunosuppressive microenvironment. For digestive system cancers, age-related damage to the intestinal mucosal barrier, the aging of gut-associated lymphoid tissue (GALT), exposure to xenobiotic stimuli throughout life, and dysbiosis make the local immune microenvironment more vulnerable. This article systematically reviews the research progress of immunosenescence and immune microenvironment in digestive system cancers, as well as the exploration of related therapy strategies, hoping to point out new directions for research in the digestive system cancers.

Sesamol Alleviated Lipotoxicity-Induced Dysfunction in MIN6 Cells via Facilitating Cellular Senescence Caused by Endoplasmic Reticulum Stress

Obesity is found to be a significant risk factor for type 2 diabetes mellitus (T2DM), attributed to lipotoxicity-induced β-cell dysfunction. However, the specific mechanism involved in the process remains incompletely unclarified. The current study demonstrated lipotoxicity resulted in the activation of ER stress, which increased the protein level of TXNIP, thereby inducing senescence-assiciated dysfunction in MIN6 cells under high fat environment. And we also found sesamol, a natural functional component extracted from sesame, was able to alleviate senescence-associated β-cell dysfunction induced by lipotoxicity by inhibiting ER stress and TXNIP. Our findings provided novel insights into senescence-related T2DM and propose innovative therapeutic approaches for utilizing sesamol in the treatment of T2DM in the obese elderly population.

Exploring the roles of SPARC as a proinflammatory factor and its potential as a novel therapeutic target against cardiovascular disease

Cardiovascular disease (CVD) is a leading cause of death worldwide, and the number of patients with CVD continues to increase despite extensive research and developments in this field. Chronic inflammation is a pivotal pathological component of CVD, and unveiling new proinflammatory factors will help devise novel preventive and therapeutic strategies. The extracellular matrix (ECM) not only provides structural support between cells but also contributes to cellular functions. Secreted protein acidic and rich in cysteine (SPARC) is a collagen-binding matricellular protein that is particularly induced during development and tissue remodeling. A proinflammatory role for SPARC has been demonstrated in various animal models, such as in the lipopolysaccharide-induced footpad model and dextran sodium sulfate-induced colitis model. Recent clinical studies reported a positive correlation between elevated plasma SPARC levels and hypertension, obesity, and the inflammatory marker high-sensitive C-reactive protein. In addition, SPARC gene deletion attenuates the cardiac injury induced by aging, myocardial infarction, and pressure load, suggesting that SPARC has deleterious effects on CVD. This review summarizes the regulatory and proinflammatory mechanisms of SPARC on CVD, chronic kidney disease (CKD), and cerebrovascular disease and discusses the rationale behind measuring SPARC as a biomarker of CVD and the effects of inhibition of SPARC in the prevention and treatment of CVD.

Adipose tissue in older individuals: a contributing factor to sarcopenia

Sarcopenia is a geriatric syndrome characterized by a functional decline in muscle. The prevalence of sarcopenia increases with natural aging, becoming a serious health problem among elderly individuals. Therefore, understanding the pathology of sarcopenia is critical for inhibiting age-related alterations and promoting health and longevity in elderly individuals. The development of sarcopenia may be influenced by interactions between visceral and subcutaneous adipose tissue and skeletal muscle, particularly under conditions of chronic low-grade inflammation and metabolic dysfunction. This hypothesis is supported by the following observations: (i) accumulation of senescent cells in both adipose tissue and skeletal muscle with age; (ii) gut dysbiosis, characterized by an imbalance in gut microbial communities as the main trigger for inflammation, sarcopenia, and aged adipose tissue; and (iii) microbial dysbiosis, which could impact the onset or progression of a senescent state. Moreover, adipose tissue acts as an endocrine organ, releasing molecules that participate in intricate communication networks between organs. Our discussion focuses on novel adipokines and their role in regulating adipose tissue and muscle, particularly those influenced by aging and obesity, emphasizing their contributions to disease development. On the basis of these findings, we propose that age-related adipose tissue and sarcopenia are disorders characterized by chronic inflammation and metabolic dysregulation. Finally, we explore new potential therapeutic strategies involving specialized proresolving mediator (SPM) G protein-coupled receptor (GPCR) agonists, non-SPM GPCR agonists, transient receptor potential (TRP) channels, antidiabetic drugs in conjunction with probiotics and prebiotics, and compounds designed to target senescent cells and mitigate their pro-inflammatory activity.

Novel perspectives on leptin in osteoarthritis: Focus on aging

Osteoarthritis (OA) is a common chronic joint disease characterized by articular cartilage degeneration, subchondral sclerosis, synovitis, and osteophyte formation. OA is associated with disability and impaired quality of life, particularly among the elderly. Leptin, a 16-kD non-glycosylated protein encoded by the obese gene, is produced on a systemic and local basis in adipose tissue and the infrapatellar fat pad located in the knee. The metabolic mechanisms employed by leptin in OA development have been widely studied, with attention being paid to aging as a corroborative risk factor for OA. Hence, in this review, we have attempted to establish a potential link between leptin and OA, by focusing on aging-associated mechanisms and proposing leptin as a potential diagnostic and therapeutic target in aging-related mechanisms of OA that may provide fruitful guidance and emphasis for future research.

Body Composition and Senescence: Impact of Polyphenols on Aging-Associated Events

Aging is a dynamic and progressive process characterized by the gradual accumulation of cellular damage. The continuous functional decline in the intrinsic capacity of living organisms to precisely regulate homeostasis leads to an increased susceptibility and vulnerability to diseases. Among the factors contributing to these changes, body composition-comprised of fat mass and lean mass deposits-plays a crucial role in the trajectory of a disability. Particularly, visceral and intermuscular fat deposits increase with aging and are associated with adverse health outcomes, having been linked to the pathogenesis of sarcopenia. Adipose tissue is involved in the secretion of bioactive factors that can ultimately mediate inter-organ pathology, including skeletal muscle pathology, through the induction of a pro-inflammatory profile such as a SASP, cellular senescence, and immunosenescence, among other events. Extensive research has shown that natural compounds have the ability to modulate the mechanisms associated with cellular senescence, in addition to exhibiting anti-inflammatory, antioxidant, and immunomodulatory potential, making them interesting strategies for promoting healthy aging. In this review, we will discuss how factors such as cellular senescence and the presence of a pro-inflammatory phenotype can negatively impact body composition and lead to the development of age-related diseases, as well as how the use of polyphenols can be a functional measure for restoring balance, maintaining tissue quality and composition, and promoting health.

Fisetin as a senotherapeutic agent: Evidence and perspectives for age-related diseases

Fisetin, a flavonoid naturally occurring in plants, fruits, and vegetables, has recently gained attention for its potential role as a senotherapeutic agent for the treatment of age-related chronic diseases. Senotherapeutics target senescent cells, which accumulate with age and disease, in both circulating immune cell populations and solid organs and tissues. Senescent cells contribute to development of many chronic diseases, primarily by eliciting systemic chronic inflammation through their senescence-associated secretory phenotype. Here, we explore whether fisetin as a senotherapeutic can eliminate senescent cells, and thereby alleviate chronic diseases, by examining current evidence from in vitro studies and animal models that investigate fisetin's impact on age-related diseases, as well as from phase I/II trials in various patient populations. We discuss the application of fisetin in humans, including challenges and future directions. Our review of available data suggests that targeting senescent cells with fisetin offers a promising strategy for managing multiple chronic diseases, potentially transforming future healthcare for older and multimorbid patients. However, further studies are needed to establish the safety, pharmacokinetics, and efficacy of fisetin as a senotherapeutic, identify relevant and reliable outcome measures in human trials, optimize dosing, and better understand the possible limitations of fisetin as a senotherapeutic agent.

A novel long non-coding RNA connects obesity to impaired adipocyte function

BACKGROUND

Long non-coding RNAs (lncRNAs) can perform tasks of key relevance in fat cells, contributing, when defective, to the burden of obesity and its sequelae. Here, scrutiny of adipose tissue transcriptomes before and after bariatric surgery (GSE53378) granted identification of 496 lncRNAs linked to the obese phenotype. Only expression of linc-GALNTL6-4 displayed an average recovery over 2-fold and FDR-adjusted p-value <0.0001 after weight loss. The aim of the present study was to investigate the impact on adipocyte function and potential clinical value of impaired adipose linc-GALNTL6-4 in obese subjects.

METHODS

We employed transcriptomic analysis of public dataset GSE199063, and cross validations in two large transversal cohorts to report evidence of a previously unknown association of adipose linc-GALNTL6-4 with obesity. We then performed functional analyses in human adipocyte cultures, genome-wide transcriptomics, and untargeted lipidomics in cell models of loss and gain of function to explore the molecular implications of its associations with obesity and weight loss.

RESULTS

The expression of linc-GALNTL6-4 in human adipose tissue is adipocyte-specific and co-segregates with obesity, being normalized upon weight loss. This co-segregation is demonstrated in two longitudinal weight loss studies and two cross-sectional samples. While compromised expression of linc-GALNTL6-4 in obese subjects is primarily due to the inflammatory component in the context of obesity, adipogenesis requires the transcriptional upregulation of linc-GALNTL6-4, the expression of which reaches an apex in terminally differentiated adipocytes. Functionally, we demonstrated that the knockdown of linc-GALNTL6-4 impairs adipogenesis, induces alterations in the lipidome, and leads to the downregulation of genes related to cell cycle, while propelling in adipocytes inflammation, impaired fatty acid metabolism, and altered gene expression patterns, including that of apolipoprotein C1 (APOC1). Conversely, the genetic gain of linc-GALNTL6-4 ameliorated differentiation and adipocyte phenotype, putatively by constraining APOC1, also contributing to the metabolism of triglycerides in adipose.

CONCLUSIONS

Current data unveil the unforeseen connection of adipocyte-specific linc-GALNTL6-4 as a modulator of lipid homeostasis challenged by excessive body weight and meta-inflammation.

Differences in sarcopenia indices in elderly Japanese women and their relationships with obesity classified according to waist circumference, BMI, and body fat percentage

BACKGROUND

Sarcopenic obesity (SO) is defined as a decrease in lean body mass and an increase in body fat mass (BFM) due to aging. Detecting SO in elderly women is important from the perspective of extending healthy life expectancy. While various indices of SO are currently used, there is no global consensus regarding diagnostic criteria for SO. This study aimed to examine the relationship between obesity indices (waist circumference (WC), body mass index (BMI), and body fat percentage (BFP)) and sarcopenia indices (total body muscle mass (TBM), appendicular lean mass (ALM), skeletal mass index (SMI)), and physical function (gait speed (GS), handgrip strength (HGS)).

METHODS

Subjects were 170 community-dwelling healthy elderly women aged 65-79 years (mean: 72.7 ± 5.78 years) who underwent measurements for WC, BMI, and BFP. A WC of ≥ 90cm was defined as the obese group, BMI was determined as weight (kg) divided by height squared (m2) and a cutoff of ≥ 25 kg/m2 was used to define the obesity group. BFM was measured using the bioelectrical impedance analysis (BIA) method and BFP was calculated from body weight and a cutoff of ≥ 30% was used to define the obesity group. TBM and ALM (kg) were measured using the BIA method, ALM (kg) was corrected for height (m2) to obtain SMI (kg/m2). Physical function was assessed by GS and HGS, which were measured by the 5-m walk test and a digital grip strength meter, respectively.

RESULTS

When obesity was assessed using BMI, WC and BFP, obese individuals had higher TBM, ALM and SMI, and lower GS among the sarcopenia indicators. HGS did not differ significantly between the non-obese and obese groups.

CONCLUSION

Our findings suggest HGS is thought to reflect muscle strength without being affected by obesity indices, suggesting that it may be useful in detecting possible sarcopenia in obese individuals.

Engineered Microfibers for Tissue Engineering

Hydrogel microfibers are hydrogel materials engineered into fiber structures. Techniques such as wet spinning, microfluidic spinning, and 3D bioprinting are often used to prepare microfibers due to their ability to precisely control the size, morphology, and structure of the microfibers. Microfibers with different structural morphologies have different functions; they provide a flow-through culture environment for cells to improve viability, and can also be used to induce the differentiation of cells such as skeletal muscle and cardiac muscle cells to eventually form functional organs in vitro through special morphologies. This Review introduces recent advances in microfluidics, 3D bioprinting, and wet spinning in the preparation of microfibers, focusing on the materials and fabrication methods. The applications of microfibers in tissue engineering are highlighted by summarizing their contributions in engineering biomimetic blood vessels, vascularized tissues, bone, heart, pancreas, kidney, liver, and fat. Furthermore, applications of engineered fibers in tissue repair and drug screening are also discussed.

Effect of Semaglutide on Physical Function, Body Composition, and Biomarkers of Aging in Older Adults With Overweight and Insulin Resistance: Protocol for an Open-Labeled Randomized Controlled Trial

BACKGROUND

Older adults with type 2 diabetes mellitus (T2DM) or prediabetes are at increased risk of adverse changes in body composition, physical function, and aging-related biomarkers compared to those with normal glucose tolerance. Semaglutide is a glucagon-like peptide 1 receptor agonist that has been approved for T2DM and chronic weight management. Although semaglutide is effective for weight loss and T2DM management, its effects on lean body mass, physical function, and biomarkers of aging are understudied in older adults.

OBJECTIVE

This study aims to compare the effects of lifestyle counseling with and that without semaglutide on body composition, physical function, and biomarkers of aging in older adults.

METHODS

This is an open-label randomized controlled trial. A total of 20 adults (aged 65 years and older) with elevated BMI (27-40 kg/m2) and prediabetes or well-controlled T2DM (hemoglobin A1c 5.7%-7.5%) are recruited, stratified by sex, and randomized 1:1 to one of 2 groups (semaglutide plus lifestyle counseling vs lifestyle counseling alone) and followed up for 5 months. Those in the semaglutide group are titrated to 1 mg weekly, as tolerated, for 12 weeks. Lifestyle counseling is given by registered dietitians and based on the Diabetes Prevention Program Lifestyle Change Program. Our primary outcomes include changes in lean mass, physical function, and biomarkers of aging. Body composition is measured by dual-energy x-ray absorptiometry and includes total fat mass and lean mass. Physical function is measured by 6-minute walk distance, grip strength, and short physical performance battery. Biomarkers of aging are measured in blood, skeletal muscle, and abdominal adipose tissue to include C-reactive protein, interleukin-6, tumor necrosis factors α, and β galactosidase staining.

RESULTS

The study was funded in December 2021 with a projected data collection period from spring 2023 through summer 2024.

CONCLUSIONS

Despite the elevated risk of adverse changes in body composition, physical function, and biomarkers of aging among older adults with glucose intolerance and elevated adiposity, the benefits and risks of commonly prescribed antihyperglycemic or weight loss medications such as semaglutide are understudied. This study aims to fill this knowledge gap to inform clinicians about the potential for additional clinically meaningful, nonglycemic effects of semaglutide.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05786521; https://clinicaltrials.gov/study/NCT05786521.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/62667.

Targeting Cell Senescence and Senolytics: Novel Interventions for Age-Related Endocrine Dysfunction

Multiple changes occur in hormonal regulation with aging and across various endocrine organs. These changes are associated with multiple age-related disorders and diseases. A better understanding of responsible underling biological mechanisms could help in the management of multiple endocrine disorders over and above hormone replacement therapy (HRT). Cellular senescence is involved in multiple biological aging processes and pathologies common in elderly individuals. Cellular senescence, which occurs in many older individuals but also across the lifespan in association with tissue damage, acute and chronic diseases, certain drugs, and genetic syndromes, may contribute to such endocrine disorders as osteoporosis, metabolic syndrome, and type 2 diabetes mellitus. Drugs that selectively induce senescent cell removal, "senolytics,", and drugs that attenuate the tissue-destructive secretory state of certain senescent cells, "senomorphics," appear to delay the onset of or alleviate multiple diseases, including but not limited to endocrine disorders such as diabetes, complications of obesity, age-related osteoporosis, and cancers as well as atherosclerosis, chronic kidney disease, neurodegenerative disorders, and many others. More than 30 clinical trials of senolytic and senomorphic agents have already been completed, are underway, or are planned for a variety of indications. Targeting senescent cells is a novel strategy that is distinct from conventional therapies such as HRT, and thus might address unmet medical needs and can potentially amplify effects of established endocrine drug regimens, perhaps allowing for dose decreases and reducing side effects.

Adipose tissue senescence: Biological changes, hallmarks and therapeutic approaches

Adipose tissue (AT), the largest energy storage reservoir and endocrine organ, plays a crucial role in regulating systemic energy metabolism. As one of the most vulnerable tissues during aging, the plasticity of AT is impaired. With age, AT undergoes redistribution, characterized by expansion of visceral adipose tissue (VAT) and reduction of peripheral subcutaneous adipose tissue (SAT). Additionally, age-related changes in AT include reduced adipogenesis of white adipocytes, decreased proliferation and differentiation capacity of mesenchymal stromal/stem cells (MSCs), diminished thermogenic capacity in brown/beige adipocytes, and dysregulation of immune cells. Specific and sensitive hallmarks enable the monitoring and evaluation of the biological changes associated with aging. In this study, we have innovatively proposed seven characteristic hallmarks of AT senescence, including telomere attrition, epigenetic alterations, genomic instability, mitochondrial dysfunction, disabled macroautophagy, cellular senescence, and chronic inflammation, which are intricately interconnected and mutually regulated. Finally, we discussed anti-aging strategies targeting AT, offering insights into mitigating or delaying metabolic disturbances caused by AT senescence.

DXA-based appendicular composition measures in healthy aging Caucasian Greek women: a cross-sectional study

As the global population of older persons increases, age-related medical conditions will have a greater impact on public health. DXA-derived bone and soft tissue metrics are associated with adverse clinical events in aging persons. This study aims to investigate the regional body composition of the appendices by whole-body DXA scans, and the age-related relationships between measures of bone and soft tissue in healthy Caucasian females of a Greek origin residing in the Mediterranean area. Body composition of the legs and the arms was analyzed, and lean mass (LM) and fat mass (FM) metrics were calculated in 330 women aged 20-85 years, using DXA. Peak bone mineral density (BMD) of the legs and arms was achieved between ages 20-30 and 41-50 years, respectively. The overall BMD reduction with age was for the legs 43% and the arms 32.2% (p < 0.001). Peak %LM of the legs and the arms was achieved between ages 20-30. The overall reduction of %LM with age was for the legs 22.5% (p < 0.001) and arms 6.6% (p < 0.05). Peak %FM of the legs and arms was attained between ages 31-40 and 61-70, respectively. The overall %FM reduction with age was for the legs and arms 7.5% and 1.9% (p > 0.05). In appendicular sites, Greek women reach peak values of bone mass in the legs first, in early adulthood. Bone loss predominates in the legs as women age. Also, with advancing age Greek women show preferential significant decreases of %LM and %FM in the legs as opposed to the arms. Although variation in appendicular bone and soft tissue metrics is present, the implications of variable biological crosstalks among the tissue components as women age may ultimately lay the foundation for future clinical trials aimed at healthy aging.

Investigating the Effects of Chelidonic Acid on Oxidative Stress-Induced Premature Cellular Senescence in Human Skin Fibroblast Cells

This study investigated the effects of chelidonic acid (CA) on hydrogen peroxide (H2O2) induced cellular senescence in human skin fibroblast cells (BJ). Cellular senescence is a critical mechanism that is linked to age-related diseases and chronic conditions. CA, a γ-pyrone compound known for its broad pharmacological activity, was assessed for its potential to mitigate oxidative stress and alter senescence markers. A stress-induced premature senescence (SIPS) model was designed in BJ fibroblast cells using the oxidative stress agent H2O2. After this treatment, cells were treated with CA, and the potential effect of CA on senescence was evaluated using senescence-related β-galactosidase, 4',6-diamino-2-phenylindole (DAPI), acridine-orange staining (AO), comet assay, molecular docking assays, gene expression, and protein analysis. These results demonstrate that CA effectively reduces senescence markers, including senescence-associated β-galactosidase activity, DNA damage, lysosomal activity, and oxidative stress indicators such as malondialdehyde. Molecular docking revealed CA's potential interactions with critical proteins involved in senescence signalling pathways, suggesting mechanisms by which CA may exert its effects. Gene expression and protein analyses corroborated the observed anti-senescent effects, with CA modulating p16, p21, and pRB1 expressions and reducing oxidative stress markers. In conclusion, CA appeared to have senolytic and senomorphic potential in vitro, which could mitigate and reverse SIPS markers in BJ fibroblasts.

Long noncoding RNA AI504432 upregulates FASN expression by sponging miR-1a-3p to promote lipogenesis in senescent adipocytes

Aging affects lipid metabolism and can cause obesity as it is closely related to the disorder of many lipogenic regulatory factors. LncRNAs have been recognized as pivotal regulators across diverse biological processes, but their effects on lipogenesis in aging remain to be further studied. In this work, using RNA sequencing (RNA-Seq), we found that the expression of lncRNA AI504432 was significantly upregulated in the eWAT (epididymal white adipose tissue) of aging mice, and the knockdown of AI504432 notably reduced the expression of several adipogenic genes (e.g., Cebp/α, Srebp-1c, Fasn, Acaca, and Scd1) in senescent adipocytes. The bioinformatics investigation revealed that AI504432 possessed a binding site for miR-1a-3p, and the discovery was verified by the luciferase reporter assay. The expression of Fasn was increased upon the inhibition of miR-1a-3p but restored upon the simultaneous silencing of AI504432. Taken together, our results suggested that AI504432 controlled lipogenesis through the miR-1a-3p/Fasn signaling pathway. The findings may inspire new therapeutic approaches to target imbalanced lipid homeostasis due to aging.

DNA methylation age acceleration contributes to the development and prediction of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is prevalent in the aging society. Despite body weight reduction, the prevalence of NAFLD has been increasing with aging for unknown reasons. Here, we investigate the association of DNA methylation age acceleration, a hallmark of aging, with risk of NAFLD. Genome-wide DNA methylation profiles were measured in 95 participants who developed type 2 diabetes during 4-year follow-up, and 356 randomly sampled participants from Shanghai Changfeng Study. DNA methylation age was calculated using the Horvath's method, and liver fat content (LFC) was measured using a quantitative ultrasound method. Subjects with highest tertile of DNA methylation age acceleration (≥ 9.5 years) had significantly higher LFC (7.2% vs 3.1%, P = 0.008) but lower body fat percentage (29.7% vs 33.0%, P = 0.032) than those with lowest tertile of DNA methylation age acceleration (< 4.0 years). After adjustment for age, sex, alcohol drinking, cigarette smoking, BMI, waist circumference, and different type blood cell counts, the risk of NAFLD was still significantly increased in the highest tertile group (OR, 4.55; 95% CI, 1.06-19.61). Even in subjects with similar LFC at baseline, DNA methylation age acceleration was associated with higher increase in LFC (4.0 ± 10.7% vs 0.9 ± 9.5%, P = 0.004) after a median of 4-year follow-up. Further analysis found that 6 CpGs of Horvath age predictors were associated with longitudinal changes in LFC after multivariate adjustment and located on genes that might lead to fat redistribution from peripheral adipose to liver. Combination of the key CpG methylation related to liver fat content with conventional risk factors improves the performance for NAFLD prediction.

Adipocyte-specific inactivation of NAMPT, a key NAD+ biosynthetic enzyme, causes a metabolically unhealthy lean phenotype in female mice during aging

Nicotinamide adenine dinucleotide (NAD+) is a universal coenzyme regulating cellular energy metabolism in many cell types. Recent studies have demonstrated the close relationships between defective NAD+ metabolism and aging and age-associated metabolic diseases. The major purpose of the present study was to test the hypothesis that NAD+ biosynthesis, mediated by a rate-limiting NAD+ biosynthetic enzyme, nicotinamide phosphoribosyltransferase (NAMPT), is essential for maintaining normal adipose tissue function and whole body metabolic health during the aging process. To this end, we provided in-depth and comprehensive metabolic assessments for female adipocyte-specific Nampt knockout (ANKO) mice during aging. We first evaluated body fat mass in young (≤4-mo-old), middle aged (10-14-mo-old), and old (≥18-mo-old) mice. Intriguingly, adipocyte-specific Nampt deletion protected against age-induced obesity without changing energy balance. However, data obtained from the hyperinsulinemic-euglycemic clamp procedure (HECP) demonstrated that, despite the lean phenotype, old ANKO mice had severe insulin resistance in skeletal muscle, heart, and white adipose tissue (WAT). Old ANKO mice also exhibited hyperinsulinemia and hypoadiponectinemia. Mechanistically, loss of Nampt caused marked decreases in WAT gene expression of lipogenic targets of peroxisome proliferator-activated receptor gamma (PPAR-γ) in an age-dependent manner. In addition, administration of a PPAR-γ agonist rosiglitazone restored fat mass and improved metabolic abnormalities in old ANKO mice. In conclusion, these findings highlight the importance of the NAMPT-NAD+-PPAR-γ axis in maintaining functional integrity and quantity of adipose tissue, and whole body metabolic function in female mice during aging.NEW & NOTEWORTHY Defective NAD+ metabolism is associated with aging and age-associated metabolic diseases. In the present study, we provided in-depth metabolic assessments in female mice with adipocyte-specific inactivation of a key NAD+ biosynthetic enzyme NAMPT and revealed an unexpected role of adipose tissue NAMPT-NAD+-PPAR-γ axis in maintaining functional integrity and quantity of adipose tissue and whole body metabolic health during the aging process.

Effects of different HIIT protocols on exercise performance, metabolic adaptation, and fat loss in middle-aged and older adults with overweight

Introduction: There is evidence that aging and obesity are associated with increased oxidative stress and chronic inflammation. High-intensity interval training (HIIT) may be superior to moderate-intensity continuous training (MICT) in anti-inflammatory and anti-obesity benefits. Therefore, the objective of this study is to determine which HIIT prescriptions will be more effective in reducing fat accumulation, inflammation, and improving metabolic adaptation and exercise performance in middle-aged and older overweight adults. Methods: Thirty-six middle-aged with overweight adults were divided into one of three groups: 1. L-HIIT group: the long-interval HIIT group (4 × 4 min Exercise/4 min Rest), 2. M-HIIT group: the medium-interval HIIT group (8 × 2 min Exercise/2 min Rest), 3. Control group: no exercise training intervention. All groups underwent the training stage for eight weeks (three sessions per week), followed by a detraining stage of four weeks in order to investigate the effects induced by different HIIT interventions on inflammation, metabolic adaptation, anti-fatigue and exercise performance, and fat loss Results: There was a significant physiological response in the change rate of heart rate (HR) after an acute L-HIIT session compared with an acute M-HIIT session (ΔHR: ↑49.66±16.09% vs ↑33.22±14.37%, p=0.02); furthermore, systolic blood pressure (SBP) and diastolic blood pressure (DBP) decreased significantly following a single L-HIIT session. After an eight-week training stage, the L-HIIT and M-HIIT groups exhibited a significant increase in aerobic capacity (ΔVO2peak), with values of +27.93±16.79% (p<0.001) and +18.39±8.12% (p<0.001), respectively, in comparison to the control group. Furthermore, in the L-HIIT group, the anaerobic power of relative mean power (RMP) exhibited a significant increase (p=0.019). However, following a four-week detraining stage, the adiponectin concentration remained 1.78 times higher in the L-HIIT group than in the control group (p=0.033). The results of blood sugar, blood lipids, body composition, and inflammatory markers did not indicate any improved it did not indicate any improvements from the two different HIIT protocols. Conclusions: The results indicate that an eight-week L-HIIT or M-HIIT intervention (three sessions per week, 32 minutes per session) may be an effective approach for improving aerobic capacity. It can be posited that L-HIIT may be a more advantageous mode than M-HIIT for enhancing anaerobic power, adipokine levels, and improving blood pressure in an aged and overweight population due to the induced physiological responses.

Identification of potential shared gene signatures between gastric cancer and type 2 diabetes: a data-driven analysis

Background

Gastric cancer (GC) and type 2 diabetes (T2D) contribute to each other, but the interaction mechanisms remain undiscovered. The goal of this research was to explore shared genes as well as crosstalk mechanisms between GC and T2D.

Methods

The Gene Expression Omnibus (GEO) database served as the source of the GC and T2D datasets. The differentially expressed genes (DEGs) and weighted gene co-expression network analysis (WGCNA) were utilized to identify representative genes. In addition, overlapping genes between the representative genes of the two diseases were used for functional enrichment analysis and protein-protein interaction (PPI) network. Next, hub genes were filtered through two machine learning algorithms. Finally, external validation was undertaken with data from the Cancer Genome Atlas (TCGA) database.

Results

A total of 292 and 541 DEGs were obtained from the GC (GSE29272) and T2D (GSE164416) datasets, respectively. In addition, 2,704 and 336 module genes were identified in GC and T2D. Following their intersection, 104 crosstalk genes were identified. Enrichment analysis indicated that "ECM-receptor interaction," "AGE-RAGE signaling pathway in diabetic complications," "aging," and "cellular response to copper ion" were mutual pathways. Through the PPI network, 10 genes were identified as candidate hub genes. Machine learning further selected BGN, VCAN, FN1, FBLN1, COL4A5, COL1A1, and COL6A3 as hub genes.

Conclusion

"ECM-receptor interaction," "AGE-RAGE signaling pathway in diabetic complications," "aging," and "cellular response to copper ion" were revealed as possible crosstalk mechanisms. BGN, VCAN, FN1, FBLN1, COL4A5, COL1A1, and COL6A3 were identified as shared genes and potential therapeutic targets for people suffering from GC and T2D.