Mitochondrial dysfunction in the elderly: possible role in insulin resistance

Mapping the evolution of anti-diabetic polysaccharides research: Trends, collaborations, and emerging frontiers

Diabetes Mellitus, characterized by insufficient insulin secretion, pancreatic beta cell damage, or insulin resistance, is the third most prevalent chronic metabolic disease worldwide. Polysaccharides, biocompatible natural macromolecules, have garnered significant attention for their potential in modulating diabetes through various mechanisms. Despite extensive studies, a comprehensive and impartial evaluation of anti-diabetic polysaccharides (ATDPs) research is still lacking. This study employs bibliometric and knowledge mapping techniques to analyze research trends and developments concerning ATDPs. A total of 3435 publications from 2001 to 2024 were examined, revealing a marked increase in publication volume and citation frequency, particularly since 2016. Network analysis indicates China as the leading contributor, with the highest number of publications and prominent institutions. The International Journal of Biological Macromolecules is identified as the most prolific journal in this field. Shaoping Nie stands out as a leading researcher with the highest citation frequency and h-index. Current research trends focus on the role of polysaccharides in regulating oxidative stress and inflammation, modulation of gut microbiota, and their structural characterization. Emerging studies investigate how these polysaccharides impact gut microbiota composition, enhance intestinal barrier functions, and modulate immune responses, representing cutting-edge areas in diabetes research. This research pioneers the use of bibliometric analysis to map ATDPs research trajectories, offering valuable insights into prevailing trends, emerging topics, and opportunities for future research and collaboration.

Transcriptomic and epigenomic signatures of liver metabolism and insulin sensitivity in aging mice

Age-related declines in insulin sensitivity and glucose metabolism contribute to metabolic disease. Despite the liver's central role in glucose homeostasis, a comprehensive phenotypic characterization and concurrent molecular analysis of insulin resistance and metabolic dysfunction in the aging liver is lacking. We characterized hepatic insulin resistance and mitochondrial metabolic defects through metabolic cage, hyperinsulinemic-euglycemic clamp, and tracer studies paired with transcriptomic and DNA methylation analyses in young and aged male mice. Aged mice exhibited benchmark measures of whole body and liver insulin resistance. Aged mice showed lower pyruvate dehydrogenase flux, decreased fatty acid oxidation and citrate synthase fluxes, and increased pyruvate carboxylase flux under insulin-stimulated conditions. Molecular analysis revealed age-related changes in metabolic genes Pck1, Socs3, Tbc1d4, and Enpp1. Unsupervised network analysis identified an intercorrelated phenotype module (ME-Glucose), RNA module, and DNA methylation module. The DNA methylation module was enriched for lipid metabolism pathways and TCF-1 binding, while the RNA module was enriched for MZF-1 binding and regulation by miR-155-5p. Protein-protein interaction network analysis revealed interactions between module genes and canonical metabolic pathways, highlighting genes including Ets1, Ppp1r3b, and Enpp3. This study reveals novel genes underlying age-related hepatic insulin resistance as potential targets for metabolic interventions to promote healthy aging.

Skeletal Muscle as a Mediator of Interorgan Crosstalk During Exercise: Implications for Aging and Obesity

Physical exercise is critical for preventing and managing chronic conditions, such as cardiovascular disease, type 2 diabetes, hypertension, and sarcopenia. Regular physical activity significantly reduces cardiovascular and all-cause mortality. Exercise also enhances metabolic health by promoting muscle growth, mitochondrial biogenesis, and improved nutrient storage while preventing age-related muscle dysfunction. Key metabolic benefits include increased glucose uptake, enhanced fat oxidation, and the release of exercise-induced molecules called myokines, which mediate interorgan communication and improve overall metabolic function. These myokines and other exercise-induced signaling molecules hold promise as therapeutic targets for aging and obesity-related conditions.

Role of Diabetes and its metabolic pathways in Epilepsy: An insight to various target approaches

The human brain acts as a crucial organ that requires a high glucose metabolic content. However, abnormal glucose levels act as a major factor for frequent epileptic foci. Thus, it has come to attention in the recent past that epilepsy is a metabolic problem in addition to a neurological condition. However, several studies have postulated a link between epilepsy and diabetes mellitus, but very few have emphasized the exact molecular mechanism behind it and its related specific targets. Hence, this article mainly outlines in-depth knowledge about the molecular mechanisms involved and its associated target approaches. Data from several publications, such as meta-analysis, systematic and narrative reviews, and research papers obtained from electronic databases, have been used for postulating a strong evidence in order to establish a comprehensive article addressing this problem in depth. The data discussed here have revealed how adiponectin levels and mitochondrial activity impact obesity, type 2 diabetes mellitus (T2DM), and epilepsy. We have also tried to give a brief idea about the possible theories that would also impact the severity of these two conditions, including adequate exercise and the impact of commonly used AEDs. Furthermore, one of the factors causing genetic predisposition to seizures due to glucose metabolism, such as GLUT-1 deficiency, has also been described briefly. It has to be mentioned that researchers and clinical practitioners might need to take these factors into account while discovering and evaluating a suitable novel therapeutic in the future.

The natural dihydrochalcone phloretin reduces lipid accumulation via downregulation of IIS and sbp-1/SREBP pathways in HepG2 cells and Caenorhabditis elegans

Phloretin, a natural dihydrochalcone, exhibits significant potential in modulating lipid metabolism both in vitro and in vivo. This study investigated the effects of phloretin on lipid accumulation in HepG2 cells and Caenorhabditis elegans. In HepG2 cells, phloretin reduced lipid accumulation, ROS levels, and lipid peroxidation while ameliorating mitochondrial dysfunction. It downregulated lipid synthesis genes (SREBP, FASN) and upregulated PI3K-AKT pathway genes (AKT, FOXO, MTOR). In C. elegans, phloretin alleviated lipid accumulation-induced growth and locomotor impairments, reduced lipofuscin, ROS, glucose, and triglyceride levels, and modulated amino acid and lipid metabolism pathways. Gene expression analysis revealed downregulation of sbp-1, mdt-15, fat-5, fat-6, and fat-7, and upregulation of daf-16, age-1, and skn-1. Mutant studies confirmed that phloretin's lipid-lowering effects were mediated through the IIS and sbp-1/SREBP pathways. These findings suggest phloretin is a promising candidate for regulating lipid metabolism and preventing hyperlipidemia.

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.

Protein Acetylation in Age-Related Macular Degeneration: Mechanisms, Roles, and Therapeutic Perspectives

Age-related macular degeneration (AMD) is a top cause of severe vision loss and blindness in older adults globally. This multifactorial disease arises from genetic, environmental, and age-related factors. Protein acetylation modification plays a key role in AMD progression through both epigenetic and non-epigenetic pathways. This review comprehensively discusses the multidimensional impacts of protein acetylation in AMD, particularly its dynamic regulation of angiogenesis, oxidative stress, inflammatory responses, and cellular senescence. Recent evidence shows that histone acetylation modification inhibits choroidal neovascularization (CNV) formation by regulating vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF-1α) expression, while upregulating the complement inhibitor clusterin to maintain Bruch's membrane integrity. Additionally, the NAD+-dependent deacetylase SIRT1 modulates the deacetylation of transcription factors such as PGC-1α, NF-κB, and FOXO3, enhancing mitochondrial antioxidant function and suppressing inflammatory cascades to disrupt the vicious cycle of oxidative stress and chronic inflammation. In terms of cellular senescence, histone hypoacetylation and hyperacetylation of non-histone proteins (e.g., p53, E2F1) jointly cause retinal pigment epithelial (RPE) cell-cycle arrest and autophagy imbalance, accelerating AMD progression. Genetic evidence further reveals subtype-specific expression changes and epigenetic regulatory mechanisms of histone deacetylases (HDACs), such as HDAC11 and HDAC1/3, in AMD. This article explores the clinical significance of these findings and proposes a novel combined therapeutic strategy. It involves synergistically targeting acetylation homeostasis with HDAC inhibitors (e.g., TSA, AN7) and SIRT1 activators while inhibiting abnormal angiogenesis, repairing metabolic disorders, and restoring autophagy function. This dual-targeting approach may overcome current anti-VEGF therapy limitations and open new precision management avenues for AMD.

Hyperpolarized 13C-MRS can Quantify Lactate Production and Oxidative PDH Flux in Murine Skeletal Muscle During Exercise

Existing techniques for the non-invasive in vivo study of dynamic changes in skeletal muscle metabolism are subject to several limitations, for example, poor signal-to-noise ratios which result in long scan times and low temporal resolution. Hyperpolarized [1-13C]pyruvate magnetic resonance spectroscopy (HP-MRS) allows the real-time visualization of in vivo metabolic processes and has been used extensively to study cardiac metabolism, but has not resolved oxidative phosphorylation in contracting skeletal muscle. Combining HP-MRS with an in vivo muscle hindlimb electrical stimulation protocol that modelled voluntary exercise to exhaustion allows the simultaneous real-time assessment of both metabolism and function. The aim of this work was to validate the sensitivity of the method by assessing pyruvate dehydrogenase (PDH) flux in resting vs. working muscle: measuring the production of bicarbonate (H13CO3 -), a byproduct of the PDH-catalysed conversion of [1-13C]pyruvate to acetyl-CoA. Mice (n = 6) underwent two hyperpolarized [1-13C]pyruvate injections with 13C MR spectra obtained from the gastrocnemius muscle to measure conversion of pyruvate to lactate and bicarbonate, one before the stimulation protocol with the muscle in a resting state and one during the stimulation protocol. The muscle force generated during stimulation was also measured, and 13C MRS undertaken at a point of ~50% fatigue. We observed an increase in the bicarbonate/pyruvate ratio by a factor of ~1.5×, in the lactate/pyruvate ratio of ~2.7×, together with an increase in total carbon (~1.5×) that we attribute to perfusion. This demonstrates profound differences in metabolism between the resting and exercising states. These data therefore serve as preliminary evidence that hyperpolarized 13C MRS is an effective in vivo probe of PDH flux in exercising skeletal muscle and could be used in future studies to examine changes in muscle metabolism in states of disease and altered nutrition.

Peripheral Inflammation and Insulin Resistance: Their Impact on Blood-Brain Barrier Integrity and Glia Activation in Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory impairment, and synaptic dysfunction. The accumulation of amyloid beta (Aβ) plaques and hyperphosphorylated tau protein leads to neuronal dysfunction, neuroinflammation, and glial cell activation. Emerging evidence suggests that peripheral insulin resistance and chronic inflammation, often associated with type 2 diabetes (T2D) and obesity, promote increased proinflammatory cytokines, oxidative stress, and immune cell infiltration. These conditions further damage the blood-brain barrier (BBB) integrity and promote neurotoxicity and chronic glial cell activation. This induces neuroinflammation and impaired neuronal insulin signaling, reducing glucose metabolism and exacerbating Aβ accumulation and tau hyperphosphorylation. Indeed, epidemiological studies have linked T2D and obesity with an increased risk of developing AD, reinforcing the connection between metabolic disorders and neurodegeneration. This review explores the relationships between peripheral insulin resistance, inflammation, and BBB dysfunction, highlighting their role in glial activation and the exacerbation of AD pathology.

Associations Between Physical Capability Markers and Risk of Coronary Artery Disease: A Prospective Study of 439,295 UK Biobank Participants

Background: The relationship between sarcopenia and the incidence of coronary artery disease (CAD) is not well understood. This study aimed to investigate this relationship and the modifying effect of potential risk factors. Methods: We conducted a prospective study including 439,295 individuals from the UK Biobank. The primary outcome was the incidence of CAD. The main physical capability markers for sarcopenia, grip strength and muscle mass, were investigated as risk factors of interest. Grip strength was measured using a Jamar J00105 (Lafayette, IN, USA) hydraulic hand dynamometer, while muscle mass was estimated through bioelectrical impedance. Cox proportional hazard models were employed to analyze the associations between the exposures and the risk of CAD. Results: A total of 41,564 incident cases of CAD were identified after a median follow-up of 13.15 years (IQR 12.29-13.88 years). Compared with the lowest quintile of grip strength, the adjusted HRs for incidences of CAD from the second to the fifth quintile were 0.81 (95% CI: 0.79-0.83), 0.71 (95% CI: 0.69-0.73), 0.61 (95% CI: 0.60-0.63), and 0.49 (95% CI: 0.48-0.51). The association remained significant in subgroup analysis and interactions were observed between the two exposures and sex, age, smoking status, inflammatory diseases, metabolic syndrome, and genetic predisposition (all p for interactions < 0.05). Conclusions: Physical capability markers of sarcopenia, grip strength and muscle mass, were independently associated with a dose-response decreased risk for CAD incidence, regardless of genetic predisposition and potential modifying risk factors.

Poor glycaemic control in type 2 diabetes compromises leukocyte oxygen consumption rate, OXPHOS complex content and neutrophil-endothelial interactions

The mitochondrial electron transport chain becomes overloaded in type 2 diabetes (T2D), which increases ROS (Reactive Oxygen Species) production and impairs mitochondrial function. Peripheral blood mononuclear cells (PBMCs) are critical players in the inflammatory process that underlies T2D. Poor glycaemic control in T2D is closely linked to the development of comorbidities. Our aim was to evaluate if glycaemic control in T2D has an impact on the oxygen consumption rates (OCR) of PBMC, OXPHOS complexes and inflammation. We recruited 181 subjects, consisting of 79 healthy controls, 64 patients with T2D and good glycaemic control (HbA1c<7 %), and 38 T2D patients with poor glycaemic control (HbA1c>7 %). We found a decrease in the basal OCR of PBMCs from patients with HbA1c>7 % with respect to controls (p < 0.05). Maximal OCR and spare respiratory capacity were lower in patients with HbA1c>7 % than in controls and patients with HbA1c<7 % (p < 0.05 for all). Mitochondrial ROS levels were higher in T2D patients, and particularly in the HbA1c > 7 group (p < 0.05 HbA1c<7 % vs control, p < 0.001 HbA1c>7 % vs control; p < 0.001 HbA1c > 7 vs HbA1c < 7). With respect to controls, poor glycaemic control in T2D patients was associated with a decrease in mitochondrial complex III and V (p < 0.05 and p < 0.01, respectively) and enhanced neutrophil-endothelial interactions (p < 0.001 vs controls). MPO levels were enhanced in T2D patients in general (p < 0.05 vs controls), and ICAM-1 and VCAM-1 were specifically increased in HbA1c > 7 patients vs controls (p < 0.01 and p < 0.001, respectively). Negative low-to-moderate correlations were found between HbA1c and basal respiration (r = -0.319, p < 0.05), maximal respiration (r = -0.350, p < 0.01) and spare respiratory capacity (r = -0.295, p < 0.05). Our findings suggest that poor glycaemic control during the progression of T2D compromises mitochondrial respiration and OXPHOS complex content in PBMCs. These alterations occur in parallel to enhanced neutrophil-endothelial interactions and adhesion molecule levels, leaving T2D patients with poor glycaemic control at a higher risk of developing vascular diseases.

Pan-PTM profiling identifies post-translational modifications associated with exceptional longevity and preservation of skeletal muscle function in Drosophila

Skeletal muscle weakness is a major component of age-associated frailty, but the underlying mechanisms are not completely understood. Drosophila has emerged as a useful model for studying skeletal muscle aging. In this organism, previous lab-based selection established strains with increased longevity and reduced age-associated muscle functional decline compared to a parental strain. Here, we have applied a computational pipeline (JUMPptm) for retrieving information on 8 post-translational modifications (PTMs) from the skeletal muscle proteomes of 2 long-lived strains and the corresponding parental strain in young and old age. This pan-PTM analysis identified 2470 modified sites (acetylation, carboxylation, deamidation, dihydroxylation, mono-methylation, oxidation, phosphorylation, and ubiquitination) in several classes of proteins, including evolutionarily conserved muscle contractile proteins and metabolic enzymes. PTM consensus sequences further highlight the amino acids that are enriched adjacent to the modified site, thus providing insight into the flanking residues that influence distinct PTMs. Altogether, these analyses identify PTMs associated with muscle functional decline during aging and that may underlie the longevity and negligible functional senescence of lab-evolved Drosophila strains.

The pro-inflammatory cytokine IL6 suppresses mitochondrial function via the gp130-JAK1/STAT1/3-HIF1α/ERRα axis

Chronic inflammation and a decline in mitochondrial function are hallmarks of aging. Here, we show that the two mechanisms may be linked. We found that interleukin-6 (IL6) suppresses mitochondrial function in settings where PGC1 (both PGC1α and PGC1β) expression is low. This suppression is mediated by the JAK1/STAT1/3 axis, which activates HIF1α through non-canonical mechanisms involving upregulation of HIF1A and ERRα transcription, and subsequent stabilization of the HIF1A protein by ERRα. HIF1α, in turn, inhibits ERRα, which is a master regulator of mitochondrial biogenesis, thus contributing to the inhibition of mitochondrial function. When expressed at higher levels, PGC1 rescues ERRα to boost baseline mitochondrial respiration, including under IL6-treated conditions. Our study suggests that inhibition of the IL6 signaling axis could be a potential treatment for those inflammatory settings where mitochondrial function is compromised.

An update on current type 2 diabetes mellitus (T2DM) druggable targets and drugs targeting them

Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia and affects millions of people globally. Even after advancement and development in medical science, it is a big task to achieve victory over type 2 diabetes mellitus (T2DM). T2DM can be a reason for fatal events like stroke, cardiac failure, nephropathy, and retinopathy. Many advanced antidiabetic drugs have been introduced in the market in the past two decades, leading researchers to hunt for new target proteins and their potential modulators that can help develop newer antidiabetic drugs. This review article comprises a broad literature of the latest developments in the management of T2DM concerning new target proteins, their inhibitors, or drugs from the clinical arena employed for the successful management of symptoms of T2DM using mono, dual, or triple combination medication therapy. The review categorizes antidiabetic drugs into three general classes that include conventional drug targets, currently explored targets, and upcoming emerging targets. The review aims to merge information on the medicines affecting these targets, their mechanisms, followed by the chemical structures, and recent advancements.

Brain aging shows nonlinear transitions, suggesting a midlife "critical window" for metabolic intervention

Understanding the key drivers of brain aging is essential for effective prevention and treatment of neurodegenerative diseases. Here, we integrate human brain and physiological data to investigate underlying mechanisms. Functional MRI analyses across four large datasets (totaling 19,300 participants) show that brain networks not only destabilize throughout the lifetime but do so along a nonlinear trajectory, with consistent temporal "landmarks" of brain aging starting in midlife (40s). Comparison of metabolic, vascular, and inflammatory biomarkers implicate dysregulated glucose homeostasis as the driver mechanism for these transitions. Correlation between the brain's regionally heterogeneous patterns of aging and gene expression further supports these findings, selectively implicating GLUT4 (insulin-dependent glucose transporter) and APOE (lipid transport protein). Notably, MCT2 (a neuronal, but not glial, ketone transporter) emerges as a potential counteracting factor by facilitating neurons' energy uptake independently of insulin. Consistent with these results, an interventional study of 101 participants shows that ketones exhibit robust effects in restabilizing brain networks, maximized from ages 40 to 60, suggesting a midlife "critical window" for early metabolic intervention.

Skeletal muscle mitochondrial dysfunction is associated with increased Gdf15 expression and circulating GDF15 levels in aged mice

Growth differentiation factor-15 (GDF15) is a biomarker of multiple disease states and circulating GDF15 levels are increased during aging in both pre-clinical animal models and human studies. Accordingly, multiple stressors have been identified, including mitochondrial dysfunction, that lead to induction of Gdf15 expression downstream of the integrated stress response (ISR). For some disease states, the source of increased circulating GDF15 is evident based on the specific pathology. Aging, however, presents a less tractable system for understanding the source of increased plasma GDF15 levels in that cellular dysfunction with aging can be pleiotropic and heterogeneous. To better understand which organ or organs contribute to increased circulating GDF15 levels with age, and whether changes in metabolic and mitochondrial dysfunction were associated with these potential changes, we compared young 12-week-old and middle-aged 52-week-old C57BL/6 J mice using a series of metabolic phenotyping studies and by comparing circulating levels of GDF15 and tissue-specific patterns of Gdf15 expression. Overall, we found that Gdf15 expression was increased in skeletal muscle but not liver, white or brown adipose tissue, kidney or heart of middle-aged mice, and that insulin sensitivity and mitochondrial respiratory capacity were impaired in middle-aged mice. These data suggest that early changes in skeletal muscle mitochondrial function and metabolism contribute to increased circulating GDF15 levels observed during aging.

Maximum insulin dose in patients admitted to the intensive care units with severe COVID-19 in the "Cross ICU Searchable Information System" study: A multicenter retrospective cohort study

AIMS

This study aimed to determine the maximum daily insulin dose (MDI) and associated factors in critically ill patients with coronavirus disease 2019 (COVID-19) receiving insulin therapy, under ventilator and/or extracorporeal membrane oxygenation (ECMO) management.

MATERIALS AND METHODS

This cross-sectional analysis used the Cross ICU Searchable Information System data from a Japanese multicenter retrospective observational cohort study of critically ill patients with COVID-19 receiving ventilation and/or ECMO, from February 2020 to March 2022. Maximum daily insulin dose was determined, and factors associated with it and maximum daily insulin dose per body weight were assessed using linear regression analysis.

RESULTS

The analysis included 788 patients. Their mean age, glycated hemoglobin level, maximum daily insulin dose, and time from admission to the maximum daily insulin dose were 65.2 ± 13.0 years, 7.0 ± 1.5% (53.0 ± 7.1 mmol/mol), 46.0 ± 43.6 U/day, and 7.3 ± 7.0 days, respectively. Male sex (β = 6.902, P = 0.034), body mass index (β = 1.020, P = 0.001), glycated hemoglobin (β = 12.272, P < 0.001), and having renal failure (β = 20.637, P = 0.003) were independent determinants of maximum daily insulin dose. Age (β = 0.004, P = 0.035), glycated hemoglobin (β = 0.154, P < 0.001), and having renal failure (β = 0.282, P = 0.004) were independent determinants of maximum daily insulin dose per body weight.

CONCLUSIONS

In patients with COVID-19 on ventilator and/or ECMO management, the maximum daily insulin dose reached after about 1 week of hospitalization was approximately 46.0 U/day. Glycated hemoglobin and renal failure were both associated with the maximum daily insulin dose and maximum daily insulin dose per body weight.

Management of hepatocellular carcinoma in elderly and adolescent/young adult populations

Hepatocellular carcinoma (HCC) presents unique challenges in both the elderly and adolescent/young adult (AYA) populations, requiring distinct management approaches. Recent epidemiological data show an increasing incidence of HCC in both age groups, with elderly cases rising significantly and AYA cases showing trends in specific regions. The clinical characteristics and treatment considerations vary substantially among these populations. Elderly patients with HCC typically present with hepatitis C virus infection, metabolic dysfunction-associated steatotic liver disease, well-differentiated tumors, and multiple comorbidities. In contrast, AYA patients with HCC often present with more aggressive tumor characteristics and predominantly with hepatitis B virus-related diseases. Treatment decisions for elderly patients with HCC require careful consideration of physiological reserves, comprehensive geriatric assessments, and potential complications. Recent studies have demonstrated that elderly patients can achieve outcomes comparable to younger patients across various treatment modalities when properly selected. While surgical outcomes are comparable to those of younger patients with proper selection, less-invasive options such as radiofrequency ablation or transarterial therapies may be more appropriate for some elderly patients. The treatment approach for AYA HCC emphasizes curative intent while considering long-term effects. AYA patients require specialized attention to their psychosocial needs, fertility preservation, and long-term health maintenance. Although data on AYA patients remain limited, they are known to have relatively favorable prognoses despite exhibiting more aggressive tumor characteristics. Management of HCC in both the elderly and AYA populations requires individualized approaches that consider age-specific factors. Both groups benefit from multidisciplinary team involvement and careful consideration of quality of life.

Neutrophils in MASLD and MASH

Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) and its progressive form, Metabolic Dysfunction Associated Steatohepatitis (MASH), represent significant health concerns associated with the metabolic syndrome. These conditions are characterized by excessive hepatic fat accumulation, inflammation, and potential progression to cirrhosis and hepatocellular carcinoma. Neutrophils are innate immune cells that play a pivotal role in the development of MASLD and MASH. They can infiltrate the hepatic microenvironment in response to inflammatory cytokines and damage associated molecular patterns (DAMPs) derived from the liver and exacerbate tissue damage by releasing of reactive oxygen species (ROS), cytokines, and neutrophil extracellular traps (NETs). Moreover, neutrophils can disrupt the metabolism of hepatocytes through key factors such as neutrophil elastase (NE) and human neutrophil peptides-1 (HNP-1), leading to inflammation and fibrosis, while myeloperoxidase (MPO) and lipocalin (LCN2) are involved in inflammatory and fibrotic processes. In contrast, neutrophils contribute to liver protection and repair through mechanisms involving microRNA-223 and matrix metalloproteinase 9 (MMP9). This dual role of neutrophils highlights their significance in the pathogenesis of MASLD and MASH. This review summarizes current understanding from recent studies on the involvement of neutrophils in MASLD and MASH. Understanding complex roles of neutrophils within the liver's unique microenvironment offers insights into novel therapeutic strategies, emphasizing the need for further research to explore neutrophil-targeted interventions for managing MASLD and MASH. [BMB Reports 2025; 58(3): 116-123].

Role of Mitochondrial Dynamics in Skin Homeostasis: An Update

Skin aging is the most prominent phenotype of host aging and is the consequence of a combination of genes and environment. Improving skin aging is essential for maintaining the healthy physiological function of the skin and the mental health of the human body. Mitochondria are vital organelles that play important roles in cellular mechanisms, including energy production and free radical balance. However, mitochondrial metabolism, mitochondrial dynamics, biogenesis, and degradation processes vary greatly in various cells in the skin. It is well known that mitochondrial dysfunction can promote the aging and its associated diseases of the skin, resulting in the damage of skin physiology and the occurrence of skin pathology. In this review, we summarize the important role of mitochondria in various skin cells, review the cellular responses to vital steps in mitochondrial quality regulation, mitochondrial dynamics, mitochondrial biogenesis, and mitochondrial phagocytosis, and describe their importance and specific pathways in skin aging.

In vivo medical imaging for assessing geroprotective interventions in humans

There is a growing interest in developing drugs with a general geroprotective effect, aimed at slowing down aging. Several compounds have been shown to increase the lifespan and reduce the incidence of age-related diseases in model organisms. Translating these results is challenging, due to the long lifespan of humans. To address this, we propose using a battery of medical imaging protocols that allow for assessments of age-related processes known to precede disease onset. These protocols, based on magnetic resonance imaging, positron emission-, computed-, and optical coherence tomography, are already in use in drug development and are available at most modern hospitals. Here, we outline how an informed use of these techniques allows for detecting changes in the accumulation of age-related pathologies in a diverse set of physiological systems. This in vivo imaging battery enables efficient screening of candidate geroprotective compounds in early phase clinical trials, within reasonable trial durations.

Mitochondrial calcium uptake declines during aging and is directly activated by oleuropein to boost energy metabolism and skeletal muscle performance

Mitochondrial calcium (mtCa2+) uptake via the mitochondrial calcium uniporter (MCU) couples calcium homeostasis and energy metabolism. mtCa2+ uptake via MCU is rate-limiting for mitochondrial activation during muscle contraction, but its pathophysiological role and therapeutic application remain largely uncharacterized. By profiling human muscle biopsies, patient-derived myotubes, and preclinical models, we discovered a conserved downregulation of mitochondrial calcium uniporter regulator 1 (MCUR1) during skeletal muscle aging that associates with human sarcopenia and impairs mtCa2+ uptake and mitochondrial respiration. Through a screen of 5,000 bioactive molecules, we identify the natural polyphenol oleuropein as a specific MCU activator that stimulates mitochondrial respiration via mitochondrial calcium uptake 1 (MICU1) binding. Oleuropein activates mtCa2+ uptake and energy metabolism to enhance endurance and reduce fatigue in young and aged mice but not in muscle-specific MCU knockout (KO) mice. Our work demonstrates that impaired mtCa2+ uptake contributes to mitochondrial dysfunction during aging and establishes oleuropein as a novel food-derived molecule that specifically targets MCU to stimulate mitochondrial bioenergetics and muscle performance.

The relationship between nonalcoholic fatty liver disease and frailty: A systematic review and meta-analysis

BACKGROUND AND AIM

Frailty is frequently observed in end-stage liver disease of various etiologies, but its role in nonalcoholic fatty liver disease (NAFLD) remains incompletely understood. We aimed to conduct a systematic review and meta-analysis to assess the association and prevalence of frailty in NAFLD.

METHODS

A systematic review of PubMed/MEDLINE, EMBASE, Web of Science, and Scopus was performed. The random-effects model was used to estimate the pooled prevalence of frailty. Meta-analyzed odds ratios (OR) were calculated to examine the association between frailty and NAFLD.

RESULTS

Among the initial 430 articles identified, 18 studies were included. Three studies involving 3673 participants had a pooled OR of 2.03 (95% CI: 1.51-2.72; Iˆ2 = 1.1%; p < 0.0001) for the association between frailty and NAFLD. The pooled prevalence of frailty in individuals with NAFLD was 23% (95% CI: 13%-38%; Iˆ2 = 93.5%) using the liver frailty index (LFI) and 8% (95% CI: 3%-21%; Iˆ2 = 98.1%) using the Fried frailty index (FFI). NAFLD patients' mean grip strength and balance time were 26.4 kg (95% CI: 23.0-29.8) and 23s (95% CI: 10-35), respectively. Among studies that also included individuals with liver cirrhosis, grip strength was lower in those with cirrhosis vs. the broader population of those with NAFLD.

CONCLUSIONS

Our study suggests that frailty is highly prevalent in individuals with NAFLD, with a significantly higher prevalence compared to those without NAFLD. Individuals with NAFLD have more than two-fold increased odds of frailty. Assessing frailty in NAFLD patients enables targeted management to improve outcomes.

NAD World 3.0: the importance of the NMN transporter and eNAMPT in mammalian aging and longevity control

Over the past five years, systemic NAD+ (nicotinamide adenine dinucleotide) decline has been accepted to be a key driving force of aging in the field of aging research. The original version of the NAD World concept was proposed in 2009, providing an integrated view of the NAD+-centric, systemic regulatory network for mammalian aging and longevity control. The reformulated version of the concept, the NAD World 2.0, was then proposed in 2016, emphasizing the importance of the inter-tissue communications between the hypothalamus and peripheral tissues including adipose tissue and skeletal muscle. There has been significant progress in our understanding of the importance of nicotinamide mononucleotide (NMN), a key NAD+ intermediate, and nicotinamide phosphoribosyltransferase (NAMPT), particularly extracellular NAMPT (eNAMPT). With these exciting developments, the further reformulated version of the concept, the NAD World 3.0, is now proposed, featuring multi-layered feedback loops mediated by NMN and eNAMPT for mammalian aging and longevity control.

Enhancing diabetic muscle repair through W-GA nanodots: a nanomedicinal approach to ameliorate myopathy in type 2 diabetes

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder that significantly impairs muscle regeneration following injuries, contributing to numerous complications and reduced quality of life. There is an urgent need for therapeutic strategies that can enhance muscle regeneration and alleviate these pathological mechanisms. In this study, we evaluate the therapeutic efficacy of W-GA nanodots, which are composed of gallic acid (GA) and tungstate (W6+), on muscle regeneration in type 2 diabetes mellitus (T2D)-induced muscle injury, with a focus on their anti-inflammatory and antioxidative effects.

METHODS

This study synthesized ultrasmall W-GA nanodots that were optimized for improved stability and bioactivity under physiological conditions. In vitro assessments included cell viability, apoptosis, reactive oxygen species (ROS) generation, and myotube differentiation in C2C12 myoblasts under hyperglycemic conditions. In vivo, T2D was induced in C57BL/6 mice, followed by muscle injury and treatment with W-GA. Muscle repair, fibrosis, and functional recovery were assessed through histological analysis and gait analysis using the CatWalk system.

RESULTS

The W-GA nanodots significantly enhanced muscle cell proliferation, decreased ROS, and reduced apoptosis in vitro. In vivo, compared with the control group, the W-GA-treated group exhibited notably improved muscle regeneration, decreased fibrosis, and enhanced functional recovery. The treatment notably modulated the inflammatory response and oxidative stress in diabetic muscle tissues, facilitating improved regenerative dynamics and muscle function.

CONCLUSIONS

W-GA nanodots effectively counter the pathological mechanisms of diabetic myopathy by enhancing regenerative capacity and reducing oxidative stress and inflammation. This nanomedicine approach offers a promising therapeutic avenue for improving muscle health and overall quality of life in individuals suffering from T2D. However, further studies are needed to explore the clinical applications and long-term efficacy of these nanodots in preventing diabetic complications.

Targeting early tau pathology: probiotic diet enhances cognitive function and reduces inflammation in a preclinical Alzheimer's model

BACKGROUND

Alzheimer's disease (AD) remains incurable, yet its long prodromal phase offers a crucial window for early intervention. Pretangle tau, a precursor to neurofibrillary tangles, plays a key role in early AD pathogenesis. Intervening in pretangle tau pathology could significantly delay the progression of AD. The gut-brain axis, increasingly recognized as a contributor to AD, represents a promising therapeutic target due to its role in regulating neuroinflammation and neurodegeneration. While probiotics have shown cognitive benefits in amyloid-centered AD models, their effect on pretangle tau pathology remains elusive.

METHODS

This study evaluates the effects of probiotics in a rat model of preclinical AD, specifically targeting hyperphosphorylated pretangle tau in the locus coeruleus. TH-CRE rats (N = 47; 24 females and 23 males) received either AAV carrying pseudophosphorylated human tau (htauE14) or a control virus at 3 months of age. Probiotic or control diets were administered at 9-12 months, with blood and fecal samples collected for ELISA and 16S rRNA gene sequencing. Behavioral assessments were conducted at 13-14 months, followed by analysis of brain inflammation, blood-brain barrier integrity, and GSK-3β activation.

RESULTS

Rats expressing pseudophosphorylated tau displayed impairment in spatial Y-maze (F1,39 = 4.228, p = 0.046), spontaneous object location (F1,39 = 6.240, p = 0.017), and olfactory discrimination (F1,39 = 7.521, p = 0.009) tests. Phosphorylation of tau at S262 (t3 = -4.834) and S356 (t3 = -3.258) in the locus coeruleus was parallelled by GSK-3β activation in the hippocampus (F1,24 = 10.530, p = 0.003). Probiotic supplementation increased gut microbiome diversity (F1,31 = 8.065, p = 0.007) and improved bacterial composition (F1,31 = 3.4867, p = 0.001). The enhancement in gut microbiomes was associated with enhanced spatial learning (p < 0.05), reduced inflammation indexed by Iba-1 (F1,25 = 5.284, p = 0.030) and CD-68 (F1,26 = 8.441, p = 0.007) expression, and inhibited GSK-3β in female rats (p < 0.01 compared to control females).

CONCLUSIONS

This study underscores the potential of probiotics to modulate the gut-brain axis and mitigate pretangle tau-related pathology in preclinical AD. Probiotic supplementation could offer a novel early intervention strategy for AD, highlighting the pivotal role of gut health in neurodegeneration.

Unveiling mitochondrial mysteries: Exploring novel tRNA variants in type 2 diabetes mellitus

The recent study of Ding et al provides valuable insights into the functional implications of novel mitochondrial tRNATrp and tRNASer(AGY) variants in type 2 diabetes mellitus (T2DM). This editorial explores their findings, highlighting the role of mitochondrial dysfunction in the pathogenesis of T2DM. By examining the molecular mechanisms through which these tRNA variants contribute to disease progression, the study introduces new targets for therapeutic strategies. We discuss the broader implications of these results, emphasizing the importance of understanding mitochondrial genetics in addressing T2DM.

Determinants of increased muscle insulin sensitivity of exercise-trained versus sedentary normal weight and overweight individuals

The athlete's paradox states that intramyocellular triglyceride accumulation associates with insulin resistance in sedentary but not in endurance-trained humans. Underlying mechanisms and the role of muscle lipid distribution and composition on glucose metabolism remain unclear. We compared highly trained athletes (ATHL) with sedentary normal weight (LEAN) and overweight-to-obese (OVWE) male and female individuals. This observational study found that ATHL show higher insulin sensitivity, muscle mitochondrial content, and capacity, but lower activation of novel protein kinase C (nPKC) isoforms, despite higher diacylglycerol concentrations. Notably, sedentary but insulin sensitive OVWE feature lower plasma membrane-to-mitochondria sn-1,2-diacylglycerol ratios. In ATHL, calpain-2, which cleaves nPKC, negatively associates with PKCε activation and positively with insulin sensitivity along with higher GLUT4 and hexokinase II content. These findings contribute to explaining the athletes' paradox by demonstrating lower nPKC activation, increased calpain, and mitochondrial partitioning of bioactive diacylglycerols, the latter further identifying an obesity subtype with increased insulin sensitivity (NCT03314714).

Skeletal muscle oxidative capacity related to intramyocellular lipid in young but not in older individuals

Skeletal muscles contain lipids inside and outside cells, namely intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL), respectively; lipids have also been found to be interspersed between these muscles as adipose tissue, namely intermuscular adipose tissue (IMAT). Metabolized IMCL has been recognized as an important substrate for energy production and their metabolism is determined by the muscle oxidative capacity. Therefore, it has been speculated that muscle oxidative capacity is related to muscle lipid content. Excessive accumulation of EMCL and IMAT has been confirmed in older individuals, leading to metabolic disorders and a decline in muscle strength. However, whether EMCL and IMAT contribute to muscle lipid metabolism remains unknown. This study aimed to investigate whether muscle oxidative capacity is related to IMCL, EMCL, and IMAT in young and older individuals. A total of 18 young and 14 older individuals were included and their muscle oxidative capacity was assessed based on the recovery rate of muscle oxygen saturation after exercise, using near-infrared spectroscopy of the medial gastrocnemius. IMCL, EMCL, and IMAT were assessed using magnetic resonance spectroscopy and imaging. A relationship between muscle oxidative capacity and IMCL was confirmed in young (r = -0.47, P < 0.05) but not older individuals (r = 0.22, P = 0.45). Muscle oxidative capacity was not related to EMCL or IMAT in either young or older individuals. These results suggest that IMCL in young individuals can contribute to muscle lipid metabolism, but not EMCL and IMAT, and this relationship differs with aging.

Lithocholic acid phenocopies anti-ageing effects of calorie restriction

Calorie restriction (CR) is a dietary intervention used to promote health and longevity1,2. CR causes various metabolic changes in both the production and the circulation of metabolites1; however, it remains unclear which altered metabolites account for the physiological benefits of CR. Here we use metabolomics to analyse metabolites that exhibit changes in abundance during CR and perform subsequent functional validation. We show that lithocholic acid (LCA) is one of the metabolites that alone can recapitulate the effects of CR in mice. These effects include activation of AMP-activated protein kinase (AMPK), enhancement of muscle regeneration and rejuvenation of grip strength and running capacity. LCA also activates AMPK and induces life-extending and health-extending effects in Caenorhabditis elegans and Drosophila melanogaster. As C. elegans and D. melanogaster are not able to synthesize LCA, these results indicate that these animals are able to transmit the signalling effects of LCA once administered. Knockout of AMPK abrogates LCA-induced phenotypes in all the three animal models. Together, we identify that administration of the CR-mediated upregulated metabolite LCA alone can confer anti-ageing benefits to metazoans in an AMPK-dependent manner.

TNFα-CXCR1/2 partners in crime in insulin resistance conditions

Type 2 diabetes mellitus (T2D) is defined by chronic hyperglycemia due to insufficient insulin secretion or activity and decreased insulin sensitivity, known as insulin resistance (IR). This condition leads to oxidative stress and inflammation, increasing the risk of systemic inflammatory diseases. Obesity and a sedentary lifestyle are major risk factors for IR and T2D. Various metabolites act as mediators of IR by disrupting communication between organs. Lipids, including free fatty acids and short-chain fatty acids, along with intracellular lipotoxins, impair insulin function and mitochondrial activity, contributing to IR through direct and indirect mechanisms such as oxidative stress and inflammation. Our research explores the role of TNFα and CXCR1/2 in IR conditions, emphasizing their interactions and potential as therapeutic targets. In this study we selected two models of IR, adipocytes and hepatocytes, since are key players in glucose and lipid metabolism. To develop IR model, TNFα was used as challenge and we focused on investigating the role of CXCR1/2 inhibition. We assessed glucose uptake, insulin signaling pathways, and gene expression related to IR. Cells treated with TNFα showed reduced p-Akt and increased p-JNK levels, indicative of IR. In contrast, CXCR1/2 inhibition restored p-Akt levels and reduced p-JNK levels, suggesting improvements in insulin signaling and glucose uptake. Furthermore, CXCR1/2 inhibition counteracted the TNFα-induced decrease in IGF expression and restored GLUT2 expression, indicating enhanced insulin sensitivity. These results underscore the pivotal role of CXCR1/2 in modulating the inflammatory response and insulin signaling in IR conditions in both IR models. CXCR1/2 inhibition can mitigate IR and improve glucose metabolism. Thus, targeting the TNFα-CXCR1/2 pathway presents a promising therapeutic approach for managing IR and T2D. Further investigation is necessary to understand the clinical implications of these findings and develop effective treatments for patients with IR and T2D.

Effect of Weight Loss on Skeletal Muscle Bioactive Lipids in People With Obesity and Type 2 Diabetes

Muscle sn-1,2-diacylglycerol (DAG) and C18:0 ceramide accumulation in sarcolemmal and mitochondrial compartments have been proposed to regulate muscle insulin sensitivity. Here, we evaluated whether weight loss-induced improvements in insulin sensitivity were associated with changes in muscle sn-1,2-DAG and ceramide content in people with obesity and type 2 diabetes. We measured skeletal muscle insulin sensitivity, assessed by using the hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotopically labeled glucose tracer infusion, and skeletal muscle sn-1,2-DAG and ceramide contents by using liquid chromatography-tandem mass spectrometry after subcellular fractionation and DAG isomer separation in 14 adults with obesity and type 2 diabetes before and after marked (18.6 ± 2.1%) weight loss. Whole-body insulin sensitivity doubled after weight loss. Sarcolemmal sn-1,2-DAG and C18:0 ceramide contents after weight loss were not different from values before weight loss. In contrast, mitochondrial-endoplasmic reticulum (ER) C18:0 ceramide content decreased by ∼20% after weight loss (from 2.16 ± 0.08 to 1.71 ± 0.13 nmol/g, P < 0.005). These results suggest a decrease in muscle mitochondrial-ER C18:0 ceramide content could contribute to the beneficial effect of weight loss on skeletal muscle insulin sensitivity.

ARTICLE HIGHLIGHTS

Neuronal Cell Rearrangement During Aging: Antioxidant Compounds as a Potential Therapeutic Approach

Aging is a natural process that leads to time-related changes and a decrease in cognitive abilities, executive functions, and attention. In neuronal aging, brain cells struggle to respond to oxidative stress. The structure, function, and survival of neurons can be mediated by different pathways that are sensitive to oxidative stress and age-related low-energy states. Mitochondrial impairment is one of the most noticeable signs of brain aging. Damaged mitochondria are thought to be one of the main causes that feed the inflammation related to aging. Also, protein turnover is involved in age-related impairments. The brain, due to its high oxygen usage, is particularly susceptible to oxidative damage. This review explores the mechanisms underlying neuronal cell rearrangement during aging, focusing on morphological changes that contribute to cognitive decline and increased susceptibility to neurodegenerative diseases. Potential therapeutic approaches are discussed, including the use of antioxidants (e.g., Vitamin C, Vitamin E, glutathione, carotenoids, quercetin, resveratrol, and curcumin) to mitigate oxidative damage, enhance mitochondrial function, and maintain protein homeostasis. This comprehensive overview aims to provide insights into the cellular and molecular processes of neuronal aging and highlight promising therapeutic avenues to counteract age-related neuronal deterioration.

Mapping the mitochondrial landscape in T2DM: key findings from 2003-2023

Backgound

T2DM, a chronic metabolic disorder, poses a significant threat to global public health. Mitochondria play a crucial role in the pathogenesis of T2DM. This study intends to investigate the correlation between mitochondria and T2DM over the past two decades (2003-2023) through bibliometric analysis. Its objectives are to pinpoint trends, emphasize research priorities, and establish a foundation for future investigations.

Methods

A literature search was conducted using the SCI-E database. All recorded results were downloaded in plain text format for further analysis. The following terms were analyzed using Vosviewer 1.6.18, citespace 6.3r1, bibliometrix in RStudio (v.4.4.1), and Microsoft Excel 2021: country, institution, author, journal, references, and keywords.

Results

From January 1, 2003 to December 31, 2023, a total of 2,732 articles were retrieved. The United States, China, and Italy contributed most of the records. UNIVERSITY OF CALIFORNIA SYSTEM, INSTITUT NATIONAL DE LA SANTE ET DE LA RECHERCHE MEDICAL INSERM, and US DEPARTMENT OF VETERANS AFFAIRS were the top 3 most productive institutions. rocha milagros, victor victor m had the most publications, followed by roden michael, and petersen kf had the most citations together. DIABETES published the most articles on research on this topic, followed by AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM, DIABETOLOGIA. The key points of this topic are the relationship between mitochondria and T2DM, the skeletal muscle mitochondrial changes observed in T2DM, and the impact of mitochondrial dysfunction on T2DM. Over the past five years, particle dynamics, mitochondrial dysfunction, and mechanism research have emerged as significant focal points in this field.

Conclude

This paper successfully identified the key areas and emerging trends in the relationship between mitochondria and T2DM, thereby offering valuable insights for future research.

Brown adipose tissue: a potential target for aging interventions and healthy longevity

Brown Adipose Tissue (BAT) is a type of fat tissue that can generate heat and plays an important role in regulating body temperature and energy metabolism. Enhancing BAT activity through medication, exercise and other means has become a potential effective method for treating metabolic disorders. Recently, there has been increasing evidence suggesting a link between BAT and aging. As humans age, the volume and activity of BAT decrease, which may contribute to the development of age-related diseases. Multiple organelles signaling pathways have been reported to be involved in the aging process associated with BAT. Therefore, we aimed to review the evidence related to the association between aging process and BAT decreasing, analyze the potential of BAT as a predictive marker for age-related diseases, and explore potential therapeutic strategies targeting BAT for aging interventions and healthy longevity.

The updated understanding of advanced maternal age

The rising rates of pregnancies associated with advanced maternal age (AMA) have created unique challenges for healthcare systems worldwide. The elevated risk of poor maternal outcomes among AMA pregnancies is only partially understood and hotly debated. Specifically, AMA is associated with reduced fertility and an increased incidence of pregnancy complications. Finding a balance between global fertility policy, socioeconomic development and health care optimization ultimately depends on female fertility. Therefore, there is an urgent need to develop technologies and identify effective interventions. Support strategies should include prepregnancy screening, intervention and postpartum maintenance. Although some reviews have considered the relationship between AMA and adverse pregnancy outcomes, no previous work has comprehensively considered the long-term health effects of AMA on mothers. In this review, we will begin by presenting the current knowledge of global health issues associated with AMA and the effects of advanced age on the female reproductive system, endocrine metabolism, and placental function. We will then discuss physiological alterations, pregnancy complications, and long-term health problems caused by AMA.

Aging delays the suppression of lipolysis and fatty acid oxidation in the postprandial period

Plasma glycerol and free fatty acid concentrations decrease following oral glucose consumption, but changes in the rate of lipolysis during an oral glucose tolerance test (OGTT) have not been documented in conjunction with changes in fatty acid (FA) oxidation or reesterification rates in healthy individuals. After a 12-h overnight fast, 15 young (21-35 yr; 7 men and 8 women) and 14 older (60-80 yr; 7 men and 7 women) participants had the forearm vein catheterized for primed continuous infusion of [1,1,2,3,3-2H]glycerol. A contralateral hand vein was catheterized for arterialized blood sampling. Indirect calorimetry was performed simultaneously to determine total FA and carbohydrate (CHO) oxidation rates (Rox). Total FA reesterification rates (Rs) were estimated from tracer-measured lipolytic and FA oxidation rates. After a 90-min equilibration period, participants underwent a 120-min, 75-g OGTT. Glycerol rate of appearance (Ra), an index of lipolysis, decreased significantly from baseline 5 min postchallenge in young participants and 30 min in older participants. At 60 min, FA Rox decreased in both groups, but was significantly higher in older participants. Between 5 and 90 min, CHO Rox was significantly lower in older participants. In addition, FA Rs was significantly lower in older participants at 60 and 90 min. The area under the curve (AUC) for FA Rox was greater than that for FA Rs in older, but not in young participants. Our results indicate that, in aging, the postprandial suppression of lipolysis and FA oxidation are delayed such that FA oxidation is favored over CHO oxidation and FA reesterification.NEW & NOTEWORTHY To our knowledge, our investigation is the first to demonstrate changes in lipolysis during an oral glucose tolerance test (OGTT) in healthy young and older individuals. Plasma glycerol and free fatty acid concentrations changed after glycerol rate of appearance (Ra), indicating that plasma concentrations are incomplete surrogates of the lipolytic rate. Moreover, simultaneous determinations of substrate oxidation rates are interpreted to indicate that metabolic inflexibility in aging is characterized by delayed changes in postprandial substrate utilization related to the lipolytic rate.

Sarcopenia and survival in colorectal cancer without distant metastasis: a systematic review and meta-analysis

BACKGROUND AND AIM

Despite prior attempts to evaluate the effects of sarcopenia on survival among patients with colorectal cancer (CRC), the results of these studies have not been consistent. The present study aimed to evaluate the association between sarcopenia and survival among patients having CRC without distant metastasis by aggregating multiple studies.

METHODS

We performed a literature search using computerized databases and identified additional studies from among the bibliographies of retrieved articles. The quality of each study was evaluated using the Newcastle-Ottawa Scale, and meta-analyses were performed to evaluate overall survival (OS) and disease-free survival (DFS).

RESULTS

Thirteen studies with up to 6600 participants were included in the meta-analyses, with a mean age of 63.6 years (range: 18-93 years). We found that preoperative sarcopenia was associated with worse OS (hazard ratio [HR]: 1.61; 95% confidence interval [CI]: 1.38-1.88) and worse DFS (HR: 1.57; 95% CI: 1.10-2.24). Compared with patients without sarcopenia after tumor resection, those with postoperative sarcopenia had worse OS (HR: 1.76; 95% CI: 1.47-2.10) and DFS (HR: 1.79; 95% CI: 1.46-2.20).

CONCLUSION

These meta-analyses suggest that sarcopenia, no matter observed before or after tumor resection, is associated with worse OS and DFS in patients with CRC who have no distant metastasis.

Signaling Pathways Concerning Mitochondrial Dysfunction: Implications in Neurodegeneration and Possible Molecular Targets

Mitochondrion is an important organelle present in our cells responsible for meeting energy requirements. All higher organisms rely on efficient mitochondrial bioenergetic machinery to sustain life. No other respiratory process can produce as much power as generated by mitochondria in the form of ATPs. This review is written in order to get an insight into the magnificent working of mitochondrion and its implications in cellular homeostasis, bioenergetics, redox, calcium signaling, and cell death. However, if this machinery gets faulty, it may lead to several disease states. Mitochondrial dysfunctioning is of growing concern today as it is seen in the pathogenesis of several diseases which includes neurodegenerative disorders, cardiovascular disorders, diabetes mellitus, skeletal muscle defects, liver diseases, and so on. To cover all these aspects is beyond the scope of this article; hence, our study is restricted to neurodegenerative disorders only. Moreover, faulty functioning of this organelle can be one of the causes of early ageing in individuals. This review emphasizes mutations in the mitochondrial DNA, defects in oxidative phosphorylation, generation of ROS, and apoptosis. Researchers have looked into new approaches that might be able to control mitochondrial failure and show a lot of promise as treatments.

Mitochondrial respiratory capacity is not altered in aging rat brains with or without memory impairment

Mitochondria are essential for supporting the high metabolic demands that are required for brain function. Impairments in mitochondria have been linked to age-related decline in brain functions. Here, we investigate whether the mitochondrial respiratory capacity of brain cells is changed in cognitive aging. We used a rat model of normal cognitive aging and analyzed mitochondrial oxidative phosphorylation in frozen brain samples. Mitochondrial oxygen consumption rate analysis of the frontal cortex did not show any differences between young rats and aged rats with either intact memory or impaired spatial memory. Mitochondrial ATP synthase activity and quantity also did not differ between young and aged rats. These results suggest that the total level of mitochondrial respiratory capacity is preserved in the frontal cortex of aged rats and may not explain aging-associated cognitive impairment.

Relationships among Dioxin-like Mitochondria Inhibitor Substances (MIS)-Mediated Mitochondria Dysfunction, Obesity, and Lung Function in a Korean Cohort

Mitochondrial dysfunction is closely linked to obesity and diabetes, with declining lung function in aging increasing diabetes risk, potentially due to elevated serum levels of dioxin-like mitochondria inhibitor substances (MIS) from prolonged exposure to environmental pollutants. However, the mechanisms connecting MIS, mitochondria, lung function, and metabolic disorder remain unclear. In this study, we analyzed data from 1371 adults aged 40-69 years in the 2008 Korean Genome Epidemiologic Study (KoGES) Ansung cohort. We indirectly estimated dioxin-like MIS levels by measuring intracellular ATP (MISATP) and reactive oxygen species (MISROS) in cultured cells treated with the serum of participants. Using correlation analysis and structural equation modeling (SEM), we explored the relationships among MIS, mitochondrial function, body mass index (BMI), and lung function (FEV1 and FVC). Our findings revealed that MISATP was associated with BMI in females and with FVC in males, while MISROS correlated with both BMI and FVC in males, not in females. Significant associations between BMI and FVC were found in the highest MIS subgroup in both sexes. SEM analyses demonstrated that MIS negatively influenced mitochondrial function, which in turn affected BMI and lung function. Age-related declines in lung function were also linked to mitochondrial dysfunction. This study underscores the potential of MIS assays as alternatives for assessing mitochondrial function and highlights the importance of mitochondrial health in metabolic disorders and lung function.

Omega-3 PUFAs slow organ aging through promoting energy metabolism

Energy metabolism disorder, mainly exhibiting the inhibition of fatty acid degradation and lipid accumulation, is highly related with aging acceleration. However, the intervention measures are deficient. Here, we reported Omega-3 polyunsaturated fatty acids (Omega-3 PUFAs), especially EPA, exerted beneficial effects on maintaining energy metabolism and lipid homeostasis to slow organ aging. As the endogenous agonist of peroxisome proliferator-activated receptor α (PPARα), Omega-3 PUFAs significantly boosted fatty acid β-oxidation and ATP production in multiple aged organs. Consequently, Omega-3 PUFAs effectively inhibited age-related pathological changes, preserved organ function, and retarded aging process. The beneficial effects of Omega-3 PUFAs were also testified in mfat-1 transgenic mice, which spontaneously generate abundant endogenous Omega-3 PUFAs. In conclusion, our study innovatively demonstrated Omega-3 PUFAs administration in diet slow aging through promoting energy metabolism. The supplement of Omega-3 PUFAs or fat-1 transgene provides a promising therapeutic approach to promote healthy aging in the elderly.

Mitigating disuse-induced skeletal muscle atrophy in ageing: Resistance exercise as a critical countermeasure

The gradual deterioration of physiological systems with ageing makes it difficult to maintain skeletal muscle mass (sarcopenia), at least partly due to the presence of 'anabolic resistance', resulting in muscle loss. Sarcopenia can be transiently but markedly accelerated through periods of muscle disuse-induced (i.e., unloading) atrophy due to reduced physical activity, sickness, immobilisation or hospitalisation. Periods of disuse are detrimental to older adults' overall quality of life and substantially increase their risk of falls, physical and social dependence, and early mortality. Disuse events induce skeletal muscle atrophy through various mechanisms, including anabolic resistance, inflammation, disturbed proteostasis and mitochondrial dysfunction, all of which tip the scales in favour of a negative net protein balance and subsequent muscle loss. Concerningly, recovery from disuse atrophy is more difficult for older adults than their younger counterparts. Resistance training (RT) is a potent anabolic stimulus that can robustly stimulate muscle protein synthesis and mitigate muscle losses in older adults when implemented before, during and following unloading. RT may take the form of traditional weightlifting-focused RT, bodyweight training and lower- and higher-load RT. When combined with sufficient dietary protein, RT can accelerate older adults' recovery from a disuse event, mitigate frailty and improve mobility; however, few older adults regularly participate in RT. A feasible and practical approach to improving the accessibility and acceptability of RT is through the use of resistance bands. Moving forward, RT must be prescribed to older adults to mitigate the negative consequences of disuse atrophy.

The onset and the development of cardiometabolic aging: an insight into the underlying mechanisms

Metabolic compromise is crucial in aggravating age-associated chronic inflammation, oxidative stress, mitochondrial damage, increased LDL and triglycerides, and elevated blood pressure. Excessive adiposity, hyperglycemia, and insulin resistance due to aging are associated with elevated levels of damaging free radicals, inducing a proinflammatory state and hampering immune cell activity, leading to a malfunctioning cardiometabolic condition. The age-associated oxidative load and redox imbalance are contributing factors for cardiometabolic morbidities via vascular remodelling and endothelial damage. Recent evidence has claimed the importance of gut microbiota in maintaining regular metabolic activity, which declines with chronological aging and cardiometabolic comorbidities. Genetic mutations, polymorphic changes, and environmental factors strongly correlate with increased vulnerability to aberrant cardiometabolic changes by affecting key physiological pathways. Numerous studies have reported a robust link between biological aging and cardiometabolic dysfunction. This review outlines the scientific evidence exploring potential mechanisms behind the onset and development of cardiovascular and metabolic issues, particularly exacerbated with aging.

Targeting the Epigenetic Marks in Type 2 Diabetes Mellitus: Will Epigenetic Therapy Be a Valuable Adjunct to Pharmacotherapy?

Although genetic, environmental, and lifestyle factors largely contribute to type 2 diabetes mellitus (T2DM) risk, the role of epigenetics in its pathogenesis is now well established. The epigenetic mechanisms in T2DM mainly consist of DNA methylation, histone modifications and regulation by noncoding RNAs (ncRNAs). For instance, DNA methylation at CpG islands in the promoter regions of specific genes encoding insulin signaling and glucose metabolism suppresses these genes. Modulating the enzyme mediators of these epigenetic marks aims to restore standard gene expression patterns and improve glycemic control. In targeting these epigenetic marks, using epigenetic drugs such as DNA methyltransferase (DNAMT), histone deacetylase (HDAC) and histone acetyltransferase (HAT) inhibitors has led to variable success in humans and experimental murine models. Specifically, the United States' Food and Drug Administration (US FDA) has approved DNAMT inhibitors like 5-azacytidine and 5-aza-2'-deoxycytidine for use in diabetic retinopathy: a T2DM microvascular complication. These DNAMT inhibitors block the genes for methylation of mitochondrial superoxide dismutase 2 (SOD2) and matrix metallopeptidase 9 (MMP-9): the epigenetic marks in diabetic retinopathy. Traditional pharmacotherapy with metformin also have epigenetic effects in T2DM and positively alter disease outcomes when combined with epigenetic drugs like DNAMT and HDAC inhibitors, raising the prospect of using epigenetic therapy as a valuable adjunct to pharmacotherapy. However, introducing small interfering RNAs (siRNAs) in cells to silence specific target genes remains in the exploratory phase. Future research should focus on regulating gene expression in T2DM using long noncoding RNA (lncRNA) molecules, another type of ncRNA. This review discusses the epigenetics of T2DM and that of its macro- and microvascular complications, and the potential benefits of combining epigenetic therapy with pharmacotherapy for optimal results.

Low blood glucose and fatigue accumulation at peak hours of occupational trauma in secondary industry workers

Objectives. The incidence of occupational traumatic injuries caused by human error has been reported to occur at 11:00 and 8-9 h after commencing work. Impaired attention is closely related to the incidence of these accidents. Therefore, this study aimed to clarify the changes in blood glucose, fatigue and stress response hormone levels over time among workers in a secondary industry. Methods. The blood glucose and subjective fatigue levels of 26 male secondary-industry workers were measured on workdays. In addition, the cortisol and dehydroepiandrosterone levels in saliva were measured on one workday and one holiday. Results. Blood glucose levels at 11:00 and 17:30 on the workday were significantly lower than those at 09:30. Moreover, hypoglycemia was observed in some participants. A significant increase in subjective fatigue levels was observed during the workday. However, no significant differences in salivary cortisol levels were observed between the workday and the holiday at any time point. Conclusions. Blood glucose levels decreased and subjective fatigue levels increased at the time points that occupational accidents were reported to occur most frequently during work. These factors may contribute to human errors due to impaired attentional function.

Mitochondrial dysfunction in the pathogenesis of endothelial dysfunction

Cardiovascular diseases (CVDs) are a matter of concern worldwide, and mitochondrial dysfunction is one of the major contributing factors. Vascular endothelial dysfunction has a major role in the development of atherosclerosis because of the abnormal chemokine secretion, inflammatory mediators, enhancement of LDL oxidation, cytokine elevation, and smooth muscle cell proliferation. Endothelial cells transfer oxygen from the pulmonary circulatory system to the tissue surrounding the blood vessels, and a majority of oxygen is transferred to the myocardium by endothelial cells, which utilise a small amount of oxygen to generate ATP. Free radicals of oxide are produced by mitochondria, which are responsible for cellular oxygen uptake. Increased mitochondrial ROS generation and reduction in agonist-stimulated eNOS activation and nitric oxide bioavailability were directly linked to the observed change in mitochondrial dynamics, resulting in various CVDs and endothelial dysfunction. Presently, the manuscript mainly focuses on endothelial dysfunction, providing a deep understanding of the various features of mitochondrial mechanisms that are used to modulate endothelial dysfunction. We talk about recent findings and approaches that may make it possible to detect mitochondrial dysfunction as a potential biomarker for risk assessment and diagnosis of endothelial dysfunction. In the end, we cover several targets that may reduce mitochondrial dysfunction through both direct and indirect processes and assess the impact of several different classes of drugs in the context of endothelial dysfunction.

Ethnicity-related differences in mitochondrial regulation by insulin stimulation in diabetes

Mitochondrial dysfunction has long been implicated in the development of insulin resistance, which is a hallmark of type 2 diabetes. However, recent studies reveal ethnicity-related differences in mitochondrial processes, underscoring the need for nuance in studying mitochondrial dysfunction and insulin sensitivity. Furthermore, the higher prevalence of type 2 diabetes among African Americans and individuals of African descent has brought attention to the role of ethnicity in disease susceptibility. In this review, which covers existing literature, genetic studies, and clinical data, we aim to elucidate the complex relationship between mitochondrial alterations and insulin stimulation by considering how mitochondrial dynamics, contact sites, pathways, and metabolomics may be differentially regulated across ethnicities, through mechanisms such as single nucleotide polymorphisms (SNPs). In addition to achieving a better understanding of insulin stimulation, future studies identifying novel regulators of mitochondrial structure and function could provide valuable insights into ethnicity-dependent insulin signaling and personalized care.

Muscle mitochondrial function is impaired in adults with type 1 diabetes

AIMS

Type 1 diabetes has been associated with mitochondrial dysfunction. However, the mechanism of this dysfunction in adults remains unclear.

METHODS

A secondary analysis was conducted using data from several clinical trials measuring in-vivo and ex-vivo mitochondrial function in adults with type 1 diabetes (n = 34, age 38.8 ± 14.6 years) and similarly aged controls (n = 59, age 44.6 ± 13.9 years). In-vivo mitochondrial function was assessed before, during, and after isometric exercise with 31phosphorous magnetic resonance spectroscopy. High resolution respirometry of vastus lateralis muscle tissue was used to assess ex-vivo measures.

RESULTS

In-vivo data showed higher rates of anaerobic glycolysis (p = 0.013), and a lower maximal mitochondrial oxidative capacity (p = 0.012) and mitochondrial efficiency (p = 0.024) in adults with type 1 diabetes. After adjustment for age and percent body fat maximal mitochondrial capacity (p = 0.014) continued to be lower and anaerobic glycolysis higher (p = 0.040) in adults with type 1 diabetes. Ex-vivo data did not demonstrate significant differences between the two groups.

CONCLUSIONS

The in-vivo analysis demonstrates that adults with type 1 diabetes have mitochondrial dysfunction. This builds on previous research showing in-vivo mitochondrial dysfunction in youths with type 1 diabetes and suggests that defects in substrate or oxygen delivery may play a role in in-vivo dysfunction.

Associations between Diabetes Mellitus and Selected Cancers

Cancer is one of the major causes of mortality and is the second leading cause of death. Diabetes mellitus is a serious and growing problem worldwide, and its prevalence continues to grow; it is the 12th leading cause of death. An association between diabetes mellitus and cancer has been suggested for more than 100 years. Diabetes is a common disease diagnosed among patients with cancer, and evidence indicates that approximately 8-18% of patients with cancer have diabetes, with investigations suggesting an association between diabetes and some particular cancers, increasing the risk for developing cancers such as pancreatic, liver, colon, breast, stomach, and a few others. Breast and colorectal cancers have increased from 20% to 30% and there is a 97% increased risk of intrahepatic cholangiocarcinoma or endometrial cancer. On the other hand, a number of cancers and cancer therapies increase the risk of diabetes mellitus. Complications due to diabetes in patients with cancer may influence the choice of cancer therapy. Unfortunately, the mechanisms of the associations between diabetes mellitus and cancer are still unknown. The aim of this review is to summarize the association of diabetes mellitus with selected cancers and update the evidence on the underlying mechanisms of this association.