Convergence of adipocyte hypertrophy, telomere shortening and hypoadiponectinemia in obese subjects and in patients with type 2 diabetes

Senescent adipocytes and type 2 diabetes - current knowledge and perspective concepts

Among civilization diseases, the number of individuals suffering from type 2 diabetes (T2DM) is expected to increase to more than a billion in less than 20 years, which is associated with, e.g., populational aging, poor diet, sedentary lifestyle, genetic predispositions, and immunological factors. T2DM affects many organs and is characterized by insulin resistance, high glucose levels, and adipocyte dysfunction, which are related to senescence. Although this type of cellular aging has beneficial biological functions, it can also act unfavorable since senescent adipocytes resist apoptosis, enhance cytokine secretion, downregulate cell identity genes, and acquire the senescence-associated secretory phenotype that renders a more oxidative environment. Opposing T2DM is possible via a wide variety of senotherapies, including senolytics and senomorphics; nevertheless, further research is advised to expand therapeutic possibilities and benefits. Consequences that ought to be deeply researched include secretory phenotype, chronic inflammation, increasing insulin resistance, as well as impairment of adipogenesis and functioning of adipocyte cells. Herein, despite reviewing T2DM and fat tissue senescence, we summarized the latest adipocyte-related anti-diabetes solutions and suggested further research directions.

Associations of genetically predicted circulating levels of cytokines with telomere length: a Mendelian randomization study

Background

Telomere length (TL) has been regarded as a biomarker of aging, and TL shortening is associated with numerous chronic illnesses. The mounting evidence has shown that inflammatory cytokines are involved in maintaining or shortening TL, the causality of cytokines with TL remains unknown. Therefore, we performed a two-sample Mendelian randomization (MR) analysis to estimate the underlying correlations of circulating inflammatory cytokines with TL.

Methods

Genetic instrumental variables for inflammatory cytokines were identified through a genome-wide association study (GWAS) involving 8,293 European individuals. Summary statistics of TL were derived from a UK Bio-bank cohort comprising 472,174 samples of individuals with European descent. We employed the inverse-variance weighted (IVW) approach as our main analysis, and to ensure the reliability of our findings, we also conducted additional analyses including the weighted median, MR-Egger, MR pleiotropy residual sum and outlier test, and weighted model. Lastly, the reverse MR analyses were performed to estimate the likelihood of inverse causality between TL and the cytokines identified in the forward MR analysis. Cochran's Q test were employed to quantify the degree of heterogeneity.

Results

After applying Bonferroni correction, a higher circulating level of Interleukin-7 (IL-7) was suggestively associated with TL maintaining (OR:1.01, 95%CI:1.00-1.02, P=0.032 by IVW method). The study also revealed suggestive evidence indicating the involvement of Interleukin-2 receptor, alpha subunit (IL-2Rα) level was negatively associated with TL maintaining (OR:0.98, 95%CI:0.96-1.00, P=0.045 by IVW method), and the weighted median approach was consistent (OR:0.99, 95%CI:0.97-1.00, P=0.035). According to the findings of reverse MR analysis, no significant causal relationship between TL and cytokines was explored. Our analysis did not reveal any substantial heterogeneity in the Single nucleotide polymorphisms or horizontal pleiotropy.

Conclusions

Our MR analysis yielded suggestive evidence supporting the causality between circulating IL-7 and IL-2Rα and telomere length, necessitating further investigations to elucidate the mechanisms by which these inflammatory cytokines may impact the progression of telomeres.

The impact of cellular senescence in human adipose tissue

In the last decades the prevalence of obesity has increased dramatically, and the worldwide epidemic of obesity and related metabolic diseases has contributed to an increased interest for the adipose tissue (AT), the primary site for storage of lipids, as a metabolically dynamic and endocrine organ. Subcutaneous AT is the depot with the largest capacity to store excess energy and when its limit for storage is reached hypertrophic obesity, local inflammation, insulin resistance and ultimately type 2 diabetes (T2D) will develop. Hypertrophic AT is also associated with a dysfunctional adipogenesis, depending on the inability to recruit and differentiate new mature adipose cells. Lately, cellular senescence (CS), an aging mechanism defined as an irreversible growth arrest that occurs in response to various cellular stressors, such as telomere shortening, DNA damage and oxidative stress, has gained a lot of attention as a regulator of metabolic tissues and aging-associated conditions. The abundance of senescent cells increases not only with aging but also in hypertrophic obesity independent of age. Senescent AT is characterized by dysfunctional cells, increased inflammation, decreased insulin sensitivity and lipid storage. AT resident cells, such as progenitor cells (APC), non-proliferating mature cells and microvascular endothelial cells are affected with an increased senescence burden. Dysfunctional APC have both an impaired adipogenic and proliferative capacity. Interestingly, human mature adipose cells from obese hyperinsulinemic individuals have been shown to re-enter the cell cycle and senesce, which indicates an increased endoreplication. CS was also found to be more pronounced in mature cells from T2D individuals, compared to matched non-diabetic individuals, with decreased insulin sensitivity and adipogenic capacity. Factors associated with cellular senescence in human adipose tissue.

Adipocyte hypertrophy in mesenchymal stem cells from infants of mothers with obesity

OBJECTIVE

Fat content of adipocytes derived from infant umbilical cord mesenchymal stem cells (MSCs) predicts adiposity in children through 4 to 6 years of age. This study tested the hypothesis that MSCs from infants born to mothers with obesity (Ob-MSCs) exhibit adipocyte hypertrophy and perturbations in genes regulating adipogenesis compared with MSCs from infants of mothers with normal weight (NW-MSCs).

METHODS

Adipogenesis was induced in MSCs embedded in three-dimensional hydrogel structures, and cell size and number were measured by three-dimensional imaging. Proliferation and protein markers of proliferation and adipogenesis in undifferentiated and adipocyte differentiating cells were measured. RNA sequencing was performed to determine pathways linked to adipogenesis phenotype.

RESULTS

In undifferentiated MSCs, greater zinc finger protein (Zfp)423 protein content was observed in Ob- versus NW-MSCs. Adipocytes from Ob-MSCs were larger but fewer than adipocytes from NW-MSCs. RNA sequencing analysis showed that Zfp423 protein correlated with mRNA expression of genes enriched for cell cycle, MSC lineage specification, inflammation, and metabolism pathways. MSC proliferation was not different before differentiation but declined faster in Ob-MSCs upon adipogenic induction.

CONCLUSIONS

Ob-MSCs have an intrinsic propensity for adipocyte hypertrophy and reduced hyperplasia during adipogenesis in vitro, perhaps linked to greater Zfp423 content and changes in cell cycle pathway gene expression.

Depot-specific adaption of adipose tissue for different exercise approaches in high-fat diet/streptozocin-induced diabetic mice

Background: Adipose tissue pathology plays a crucial role in the pathogenesis of type 2 diabetes mellitus. Understanding the impact of exercise training on adipose tissue adaptation is of paramount importance in enhancing metabolic health. In this study, we aimed to investigate the effects of various exercise modalities on three distinct adipose tissue depots, namely, interscapular brown adipose tissue (iBAT), subcutaneous white adipose tissue (sWAT), and epididymal white adipose tissue (eWAT), in a murine model of diabetes. Methods: Male C57BL/6J mice received a 12-week high-fat diet and a single injection of streptozotocin, followed by an 8-week exercise intervention. The exercise intervention included swimming, resistance training, aerobic exercise, and high-intensity interval training (HIIT). Results: We found that exercise training reduced body weight and body fat percentage, diminished adipocyte size and increased the expression of mitochondria-related genes (PGC1, COX4, and COX8B) in three adipose tissue depots. The effects of exercise on inflammatory status include a reduction in crown-like structures and the expression of inflammatory factors, mainly in eWAT. Besides, exercise only induces the browning of sWAT, which may be related to the expression of the sympathetic marker tyrosine hydroxylase. Among the four forms of exercise, HIIT was the most effective in reducing body fat percentage, increasing muscle mass and reducing eWAT adipocyte size. The expression of oxidative phosphorylation and thermogenesis-related genes in sWAT and eWAT was highest in the HIIT group. Conclusion: When targeting adipose tissue to improve diabetes, HIIT may offer superior benefits and thus represents a more advantageous choice.

The impact of moderate endurance exercise on cardiac telomeres and cardiovascular remodeling in obese rats

Introduction

Hypercaloric nutrition and physical inactivity cause obesity, a potential driver of myocardial apoptosis and senescence that may accelerate cardiac aging. Although physical activity reduces mortality, its impact on myocardial aging is insufficiently understood. Here we investigated the effects of a hypercaloric high-fat diet (HFD) and regular exercise training on cardiac cells telomeres and histomorphometric indices of cardiac aging.

Methods

Ninety-six 4-months old female Sprague-Dawley rats were fed for 10 months normal (ND) or a HFD diet. Half of the animals in each group performed 30 min treadmill-running sessions on 5 consecutive days per week. At study end, cardiomyocyte cross-sectional area (CSA), interstitial collagen content, vascular density, apoptotic and senescent cells, relative telomere length (RTL), and expression of telomerase-reverse transcriptase (Tert) as marker of telomere-related senescence and apoptosis were analyzed.

Results

Compared to ND, the HFD group developed obesity, higher CSA, lower capillary density and tended to have more apoptotic cardiomyocytes and interstitials cells. Myocardial RTL and the expression of Terf-1 and Terf-2 were comparable in sedentary HFD and ND animals. In the HFD group, regular moderate endurance exercise improved myocardial vascularization, but had no effect on CSA or apoptosis. Notably, the combination of exercise and HFD increased senescence when compared to sedentary ND or HFD, and reduced RTL when compared to exercise ND animals. Exercising HFD animals also showed a trend toward higher Tert expression compared to all other groups. In addition, exercise reduced Terf-1 expression regardless of diet.

Conclusion

HFD-induced obesity showed no effects on myocardial telomeres and induced only mild morphologic alterations. Summarized, long-term moderate endurance exercise partially reverses HFD-induced effects but may even trigger cardiac remodeling in the context of obesity.

Telomere Length and Telomerase Activity in Subcutaneous and Visceral Adipose Tissues from Obese and Non-Obese Patients with and without Colorectal Cancer

To investigate the molecular mechanisms that link obesity and colorectal cancer (CRC), we analyzed parameters related to telomere function in subcutaneous and visceral adipose tissues (SAT and VAT), including subjects with and without CRC, who were classified according to their body mass index (BMI). Adipose tissues were obtained from 147 patients who had undergone surgery. A total of 66 cases corresponded to CRC patients, and 81 subjects were not affected by cancer. Relative telomere length was established by qPCR, and telomerase activity was determined by a method based on the telomeric repeat amplification protocol. Our results indicated longer telomeres in patients affected by CRC, both in SAT and VAT, when compared to the group of subjects without CRC. Tumor local invasion was associated with telomere length (TL) in SAT. Considering the BMI values, significant differences were found in the TL of both adipose tissues between subjects affected by CRC and those without cancer. Overweight subjects showed the greatest differences, with longer telomeres in the group of CRC patients, and a higher number of cases with telomerase reactivation in the VAT of subjects without cancer. In conclusion, parameters related to telomere function in adipose tissue could be considered as potential biomarkers in the evaluation of CRC and obesity.

Fat Cell Size: Measurement Methods, Pathophysiological Origins, and Relationships With Metabolic Dysregulations

The obesity pandemic increasingly causes morbidity and mortality from type 2 diabetes, cardiovascular diseases and many other chronic diseases. Fat cell size (FCS) predicts numerous obesity-related complications such as lipid dysmetabolism, ectopic fat accumulation, insulin resistance, and cardiovascular disorders. Nevertheless, the scarcity of systematic literature reviews on this subject is compounded by the use of different methods by which FCS measurements are determined and reported. In this paper, we provide a systematic review of the current literature on the relationship between adipocyte hypertrophy and obesity-related glucose and lipid dysmetabolism, ectopic fat accumulation, and cardiovascular disorders. We also review the numerous mechanistic origins of adipocyte hypertrophy and its relationship with metabolic dysregulation, including changes in adipogenesis, cell senescence, collagen deposition, systemic inflammation, adipokine secretion, and energy balance. To quantify the effect of different FCS measurement methods, we performed statistical analyses across published data while controlling for body mass index, age, and sex.

Influence of Body Fat on Oxidative Stress and Telomere Length of Master Athletes

ABSTRACT

Aguiar, SS, Rosa, TS, Sousa, CV, Santos, PA, Barbosa, LP, Deus, LA, Rosa, EC, Andrade, RV, and Simões, HG. Influence of body fat on oxidative stress and telomere length of master athletes. J Strength Cond Res 35(6): 1693-1699, 2021-The present investigation analyzed the role of body fat and training history on biological aging of master athletes by comparing and verifying the relationships between markers of adiposity, oxidative balance, and telomere length (TL) in middle-aged runners and untrained individuals. Master athletes (sprinters and endurance runners, n = 21; 51.62 ± 8.19 years) and untrained age-matched controls (n = 11; 45.41 ± 10.34 years) had blood samples collected for biochemical and biomolecular analyzes. Pro-oxidant and antioxidant measures as well as DNA extraction were performed using commercial kits. Relative TL (T/S) was determined in leukocytes through quantitative polymerase chain reaction analyses. Master athletes had lower body fat and longer TL than untrained controls (body fat: 12.21 ± 4.14% vs. 26.03 ± 4.29%; TL: 1.10 ± 0.84 vs. 0.56 ± 0.56 T/S; p < 0.05). Furthermore, master athletes also showed a better oxidative balance than untrained controls (p < 0.05). A negative correlation was observed between TL and body fat (r = -0.471; p = 0.007), and conicity index (r = -0.407; p = 0.021), catalase activity (r = -0.569; p = 0.001), and CAT/TBARS ratio (r = -0.463; p = 0.008) for the whole sample. In conclusion, master athletes have longer TL, better oxidative profile, and lower body fat than untrained individuals. Moreover, for this middle-aged sample, body fat was inversely correlated with both TL and markers of oxidative balance, demonstrating the key role of adiposity in biological aging.

Telomere Length and Oxidative Stress and Its Relation with Metabolic Syndrome Components in the Aging

Simple Summary

A link between telomere length and some age-related diseases has been identified, including metabolic syndrome. So far, there is no mechanism to explain the origin or cause of telomere shortening in this syndrome; however, oxidative stress is a constant factor. Therefore, we reviewed scientific evidence that supported the association between oxidative stress and telomere length dynamics, also examining how each of the metabolic syndrome components individually affects the length. In this regard, there is strong scientific evidence that an increase in the number of metabolic syndrome components is associated with a shorter telomere length, oxidative damage at the lipid and DNA level, and inflammation, as well as its other components, such as obesity, hyperglycemia, and hypertension, while for dyslipidemia, there is a little more discrepancy. The difficulty for the correct treatment of metabolic syndrome lies in its multifactorial nature. Hence, there is a need to carry out more studies on healthy lifestyles during aging to prevent and reduce oxidative damage and telomere wear during aging, and consequently the progression of chronic degenerative diseases, thus improving the living conditions of older people.

Abstract

A great amount of scientific evidence supports that Oxidative Stress (OxS) can contribute to telomeric attrition and also plays an important role in the development of certain age-related diseases, among them the metabolic syndrome (MetS), which is characterised by clinical and biochemical alterations such as obesity, dyslipidaemia, arterial hypertension, hyperglycaemia, and insulin resistance, all of which are considered as risk factors for type 2 diabetes mellitus (T2DM) and cardiovascular diseases, which are associated in turn with an increase of OxS. In this sense, we review scientific evidence that supports the association between OxS with telomere length (TL) dynamics and the relationship with MetS components in aging. It was analysed whether each MetS component affects the telomere length separately or if they all affect it together. Likewise, this review provides a summary of the structure and function of telomeres and telomerase, the mechanisms of telomeric DNA repair, how telomere length may influence the fate of cells or be linked to inflammation and the development of age-related diseases, and finally, how the lifestyles can affect telomere length.

Correlation between metabolic syndrome and relative telomere length shortening in HIV/AIDS patients on combined antiretroviral therapy

BACKGROUND

Components of the metabolic syndrome (MetS) play an important role in the accelerated aging process. Relative telomere length (RTL) is a marker of biological aging. The aim of our study was to determine RTL and its possible association with MetS and the components of MetS in HIV-infected patients treated with cART.

METHODS

We included 24 HIV-infected men, all Caucasians, with successful cART (<50 HIV-RNA copies/mL) and on stable cART for at least 24 months. The presence of MetS and its components was determined by the criteria prescribed by the International Diabetes Federation. RTL was determined by Real-Time PCR and ΔΔCt method. We performed a multiple linear regression modeling on log-transformed RTL (dependant variable) to evaluate which components of the metabolic syndrome as well as cART duration and cART type, had an impact on RTL.

RESULTS

Eleven (45.8%) patients had and 13 (54.2%) had not MetS. All patients, had an undetectable viral RNA and a relatively good immune status. The mean RTL was 0.62 ± 0.15 and 0.95 ± 0.36 in patients with and without MetS, respectively (p = 0.01). Multiple linear regression model showed no significant association between duration of cART, cART type and RTL (p = 0.2165, p = 0.8628, respectively). The same analysis showed that an increase in number of MetS components was associated with shorter telomere length (β = -0.4982, p = 0.042).

CONCLUSIONS

We showed for the first time association between RTL shortening in HIV-infected men with metabolic syndrome. Furthermore, our study also indicated that an increment of metabolic syndrome components is strongly associated with shorter telomere length.

The effect of environmental Bisphenol A exposure on breast cancer associated with obesity

Bisphenol A (BPA) is a widely used endocrine disrupter. Its environmental exposure is a causative factor of cell aging via decreasing telomerase activity, thus leading to shortening of telomere length. Epidemiological studies confirm positive associations between BPA exposure and the incidence of obesity and type 2 diabetes (T2DM). Increased urinary BPA levels in obese females are both significantly correlated with shorter relative telomere length and T2DM. BPA is a critically effective endocrine disrupter leading to poor prognosis via the obesity-inflammation-aromatase axis in breast cancer. Environmental BPA exposure contributes to the progression of both estrogen dependent and triple negative breast cancers. BPA is a positive regulator of human telomerase reverse transcriptase (hTERT) and it increases the expression of hTERT mRNA in breast cancer cells. BPA exposure can lead to tamoxifen resistance. Among patients treated with chemotherapy, those with persistent high telomerase activity due to BPA are at higher risk of death.

Serum anti-inflammatory and inflammatory markers have no causal impact on telomere length: a Mendelian randomization study

INTRODUCTION

The relationship between inflammatory and anti-inflammatory markers and telomere length (TL), a biological index of aging, is still poorly understood. By applying a 2-sample Mendelian randomization (MR), we investigated the causal associations between adiponectin, bilirubin, C-reactive protein (CRP), leptin, and serum uric acid (SUA) with TL.

MATERIAL AND METHODS

MR was implemented by using summary-level data from the largest ever genome-wide association studies (GWAS) conducted on our interested exposure and TL. Inverse variance weighted method (IVW), weighted median (WM)-based method, MR-Egger, MR-Robust Adjusted Profile Score (RAPS), and MR-Pleiotropy RESidual Sum and Outlier (PRESSO) were applied. Sensitivity analysis was conducted using the leave-one-out method.

RESULTS

With regard to adiponectin, CRP, leptin, and SUA levels, we found no effect on TL for all 4 types of tests (all p > 0.108). Results of the MR-Egger (p = 0.892) and IVW (p = 0.124) showed that bilirubin had no effect on telomere maintenance, whereas the results of the WM (p = 0.030) and RAPS (p = 0.022) were negative, with higher bilirubin concentrations linked to shorter TL. There was a low likelihood of heterogeneity for all the estimations, except for bilirubin (IVW p = 0.026, MR Egger p = 0.018). MR-PRESSO highlighted no outlier. For all the estimations, we observed negligible intercepts that were indicative of low likelihood of the pleiotropy (all p > 0.161). The results of leave-one-out method demonstrated that the links are not driven because of single nucleotide polymorphisms (SNPs).

CONCLUSIONS

Our results highlight that neither the anti-inflammatory nor pro-inflammatory markers tested have any significant causal effect on TL. The casual role of bilirubin on TL still needs to be investigated.

Active surveillance in prostate cancer management: where do we stand now?

Prostate cancer (PCa) is the most common cancer in men, with a steadily rising incidence, affecting on average one in six men during their lifetime. The increase in morbidity is related to the increasing overall life expectancy, prostate-specific antigen testing, implementation of new molecular markers for cancer detection and the more frequent application of multiparametric magnetic resonance imaging. There is growing evidence demonstrating that active surveillance (AS) is an alternative to immediate intervention in patients with very low- and low-risk prostate cancer. Ongoing reports from multiple studies have consistently demonstrated a very low rate of metastases and prostate cancer specific mortality in selected cohorts of patients. As a matter of fact, AS has been adopted by many institutions as a safe and effective management strategy. The aim of our review is to summarize the contemporary data on AS in patients affected with PCa with the intention to present the most clinically useful and pertinent AS protocols.

Relationship of Telomere Length to Fat Redistribution in HIV

Persons with HIV demonstrate increased risk for aging-associated complications and have reduced telomere length (TL) compared with age-matched persons without HIV. Our data show that greater visceral fat is related to reduced TL in HIV, independent of age and smoking. Fat redistribution may be a relevant mediator of TL attrition in HIV.

Molecular basis of ageing in chronic metabolic diseases

AIM

Over the last decades, the shift in age distribution towards older ages and the progressive ageing which has occurred in most populations have been paralleled by a global epidemic of obesity and its related metabolic disorders, primarily, type 2 diabetes (T2D). Dysfunction of the adipose tissue (AT) is widely recognized as a significant hallmark of the ageing process that, in turn, results in systemic metabolic alterations. These include insulin resistance, accumulation of ectopic lipids and chronic inflammation, which are responsible for an elevated risk of obesity and T2D onset associated to ageing. On the other hand, obesity and T2D, the paradigms of AT dysfunction, share many physiological characteristics with the ageing process, such as an increased burden of senescent cells and epigenetic alterations. Thus, these chronic metabolic disorders may represent a state of accelerated ageing.

MATERIALS AND METHODS

A more precise explanation of the fundamental ageing mechanisms that occur in AT and a deeper understanding of their role in the interplay between accelerated ageing and AT dysfunction can be a fundamental leap towards novel therapies that address the causes, not just the symptoms, of obesity and T2D, utilizing strategies that target either senescent cells or DNA methylation.

RESULTS

In this review, we summarize the current knowledge of the pathways that lead to AT dysfunction in the chronological ageing process as well as the pathophysiology of obesity and T2D, emphasizing the critical role of cellular senescence and DNA methylation.

CONCLUSION

Finally, we highlight the need for further research focused on targeting these mechanisms.

Altered circulatory levels of miR-128, BDNF, cortisol and shortened telomeres in patients with type 2 diabetes and depression

AIMS

Several studies have reported the role of biomarkers either in diabetes or depression. The present study is aimed at profiling the circulating levels of miR-128, brain-derived neurotrophic factor (BDNF), cortisol and telomere length in patients with type 2 diabetes with and without depression compared to individuals with normal glucose tolerance.

METHODS

Study subjects (n = 160) were recruited from an ongoing epidemiological study in southern India. Non-diabetic and diabetic individuals were diagnosed as per the World Health Organization criteria. Depression score was derived using PHQ-12 questionnaire. Real-time quantitative PCR and ELISA methodologies were used to quantify the biomarkers.

RESULTS

Circulatory levels of miR-128 and cortisol were significantly (p < 0.05) increased with decreased BDNF levels and shortened telomeres in T2DM patients with or without depression compared to NGT individuals. T2DM patients with depression had the highest levels of miR-128 and cortisol and lowest levels of BDNF and telomere length compared to other groups. Pearson correlation analysis showed miR-128 levels were negatively associated with BDNF, telomere length and HDL cholesterol and positively correlated with cortisol, depression score, poor glycemic control and insulin resistance. Regression analysis confirmed that miR-128 was significantly associated with depression score even after adjusted for several confounding factors. However, this association was lost when adjusted for cortisol or telomere length.

CONCLUSIONS

Patients with type 2 diabetes and depression exhibited increased circulatory levels of miR-128 and serum cortisol and decreased levels of BDNF and shortened telomeres. These neuroendocrine signatures were more markedly altered in those with combined diabetes and depression.

Long-lived post-mitotic cell aging: is a telomere clock at play?

Senescence is a cellular response to stress for both dividing and post-mitotic cells. Noteworthy, long-lived post-mitotic cells (collectively named LLPMCs), which can live for decades in the organism, can exhibit a distinct type of cellular aging characterized by a progressive functional decline not associated to an overt senescence phenotype. The age-related drivers of senescence and aging in LLPMCs remain largely unknown. There is evidence that an increased production of reactive oxygen species (ROS) due to dysfunctional mitochondria, coupled with an inherent inability of cellular-degradation mechanisms to remove damaged molecules, is responsible for senescence and aging in LLPMC. Although telomeric DNA shortening, by nature linked to cell division, is generally not considered as a driver of LLPMC aging and senescence, we discuss recent reports revealing the existence of age-related telomere changes in LLPMC. These findings reveal unexpected roles for telomeres in LLPMC function and invite us to consider the hypothesis of a complex telomere clock involved in both dividing and non-dividing cell aging.

Obesity and ageing: Two sides of the same coin

Conditions and comorbidities of obesity mirror those of ageing and age-related diseases. Obesity and ageing share a similar spectrum of phenotypes such as compromised genomic integrity, impaired mitochondrial function, accumulation of intracellular macromolecules, weakened immunity, shifts in tissue and body composition, and enhanced systemic inflammation. Moreover, it has been shown that obesity reduces life expectancy by 5.8 years in men and 7.1 years in women after the age of 40. Shorter life expectancy could be because obesity holistically accelerates ageing at multiple levels. Besides jeopardizing nuclear DNA and mitochondrial DNA integrity, obesity modifies the DNA methylation pattern, which is associated with epigenetic ageing in different tissues. Additionally, other signs of ageing are seen in individuals with obesity including telomere shortening, systemic inflammation, and functional declines. This review aims to show how obesity and ageing are "two sides of the same coin" through discussing how obesity predisposes an individual to age-related conditions, illness, and disease. We will further demonstrate how the mechanisms that perpetuate the early-onset of chronic diseases in obesity parallel those of ageing.

Accelerating research on biological aging and mental health: Current challenges and future directions

Aging is associated with complex biological changes that can be accelerated, slowed, or even temporarily reversed by biological and non-biological factors. This article focuses on the link between biological aging, psychological stressors, and mental illness. Rather than comprehensively reviewing this rapidly expanding field, we highlight challenges in this area of research and propose potential strategies to accelerate progress in this field. This effort requires the interaction of scientists across disciplines - including biology, psychiatry, psychology, and epidemiology; and across levels of analysis that emphasize different outcome measures - functional capacity, physiological, cellular, and molecular. Dialogues across disciplines and levels of analysis naturally lead to new opportunities for discovery but also to stimulating challenges. Some important challenges consist of 1) establishing the best objective and predictive biological age indicators or combinations of indicators, 2) identifying the basis for inter-individual differences in the rate of biological aging, and 3) examining to what extent interventions can delay, halt or temporarily reverse aging trajectories. Discovering how psychological states influence biological aging, and vice versa, has the potential to create novel and exciting opportunities for healthcare and possibly yield insights into the fundamental mechanisms that drive human aging.

How Does Obesity and Physical Activity Affect Aging?: Focused on Telomere as a Biomarker of Aging

Obesity is known to continuously increase systemic inflammation and oxidative stress, leading to shorter telomere length. However, research regarding the correlation between physical activity, exercise, obesity, and telomere length is not consistent. Therefore, this review aims to summarize the effects of obesity, physical activity, and exercise on telomere length. Our search for effects of obesity, physical activity, and exercise, on telomeres was conducted using three computerized databases: Medline, PubMed, and EBSCO. Keywords in the search were “physical activity, exercise and obesity,” “physical activity, exercise and telomere,” and “obesity and telomere.” Improving chronic inflammation and oxidative stress levels can prevent telomere attrition due to obesity. In addition, differences in the anti-aging effects of physical activity and exercise are shown in the post-middle-age period, when telomere length changes, rather than in past exercise habits. Maintaining high cardiorespiratory fitness levels through regular exercise and physical activity in the post-middle-age period minimizes obesity-related diseases and helps maintain telomere length, which is an index of cell senescence.

Factors associated with glycemic control in community-dwelling elderly individuals with type 2 diabetes mellitus in Zhejiang, China: a cross-sectional study

BACKGROUND

Although exercise seems to be beneficial for type 2 diabetes mellitus (T2DM) patients, there is limited research elucidating the optimal accessible indices of adiposity and insulin resistance for identifying elderly T2DM patients with poor glycemic control, which could be improved by performing regular exercise.

METHODS

A community-based, cross-sectional study was conducted with 918 Chinese elderly individuals with T2DM in Zhejiang. Relevant risk factors for poor glycemic control, as determined using glycated haemoglobin A1c (HbA1c) > 7%, were explored using logistic regression analyses and included body mass index (BMI), waist circumference (WC), waist to height ratio (WHtR), fasting blood glucose (FBG), triglycerides (TGs), total cholesterol (TC), the product of fasting triglycerides and glucose (TyG), visceral adiposity index (VAI), lipid accumulation product (LAP), TyG-BMI, and TyG-WC. Comparisons of the risk factors' ability to discriminate poor glycemic control as well as their optimal cutoff values were determined using receiver operating characteristic (ROC) analyses, and then the extent of poor glycemic control risk reduction through regular exercise was examined using multivariate logistic regression analyses.

RESULTS

The overall poor glycemic control rate was 49.3%. The factors associated with poor glycemic control included FBG > 3.869, TyG > 8.73, TyG-BMI > 222.45, and TyG-WC > 713.48 in logistic regression analyses. The optimal cutoff points of FBG, TyG, TyG-WC, and TyG-BMI in discriminating poor glycemic control were 7.38, 9.22, 813.33, and 227.77, and their corresponding areas under the ROC curves were 0.864(0.840-0.886), 0.684(0.653-0.714), 0.604(0.571-0.635), and 0.574(0.541-0.606), respectively. Occasional and regular exercise reduced the odds ratios (95% confidence interval) of poor glycemic control to 0.187 (0.063-0.557) and 0.183 (0.059-0.571) for subjects with TyG-WC > 813.33 (p = 0.008), to 0.349 (0.156-0.782) and 0.284 (0.123-0.652) for subjects with TyG > 9.22 (p = 0.011), and to 0.390 (0.175-0.869) and 0.300(0.130-0.688) for subjects with TyG-BMI > 227.77 (p = 0.017), respectively, after adjusting for multiple confounding factors.

CONCLUSION

Among elderly individuals with T2DM, poor glycemic control risk might be identified using indices calculated from FBG, TG, BMI, and WC measurements, which are indicative of adiposity and insulin resistance. TyG-WC seems to be an accessible and useful indicator to identify which elderly T2DM patients would benefit from performing regular exercise to achieve good glycemic control.

L-Fucose ameliorates high-fat diet-induced obesity and hepatic steatosis in mice

Background

l-Fucose (Fuc), a six-deoxy hexose monosaccharide, is present endogenously in humans and animals and has a wide range of biological functions. In the present study, we aimed to examine the effect of Fuc on obesity and hepatic steatosis in mice fed a high-fat diet (HFD).

Methods

C57BL/6 mice were fed a normal chow (NC) or HFD for 18 weeks to induce obesity and fatty liver. Fuc was administered intragastrically from the 8th week to the end of the experiment (18 weeks).

Results

Metagenomic analysis showed that HFD altered the genomic profile of gut microbiota in the mice; specifically, expression of alpha-l-fucosidase, the gene responsible for Fuc generation, was markedly reduced in the HFD group compared with that in the NC group. Fuc treatment decreased body weight gain, fat accumulation, and hepatic triglyceride elevation in HFD-fed mice. In addition, Fuc decreased the levels of endotoxin-producing bacteria of the Desulfovibrionaceae family and restored HFD-induced enteric dysbiosis at both compositional and functional levels.

Conclusion

Our findings suggest that Fuc might be a novel strategy to treat HFD-induced obesity and fatty liver.

The potential impact of biochemical mediators on telomere attrition in major depressive disorder and implications for future study designs: A narrative review

BACKGROUND

Major depressive disorder (MDD) has been proposed to represent a "disease of premature aging", which is associated with certain biomarkers of cellular ageing and numerous other age-related diseases. Over the last decade, telomere length (TL) arose as a surrogate for cellular aging. Recent data suggests that TL might be reduced in patients with MDD, however, results are still inconclusive. This might be explained by the lack of assessment of potential biochemical mediators that are directly associated with telomere shortening and frequently observed in patients with MDD.

METHODS

A narrative review was performed. The PubMed database was searched for relevant studies.

RESULTS

We identified four major mediators, which are recurrently reported in patients with MDD and are associated with reduced TL: inflammation/oxidative stress, dysregulation of the hypothalamic-pituitary-adrenal axis, metabolic dysbalance including insulin resistance, and decreased brain-derived neurotrophic factor. These mediators are also mutually associated and were not systematically assessed in current studies investigating TL and MDD, which might explain inconclusive findings across current literature. Finally, we discuss possible ways to assess those mediators and potential implications of such approaches for future research.

LIMITATIONS

The majority of identified studies had cross-sectional designs and used heterogeneous methods to assess TL and associated relevant biochemical mediators.

CONCLUSIONS

A better understanding of the complex interactions between biochemical mediators, somatic comorbidities and shortened telomeres in patients with MDD might further specify the pathophysiology-based conceptualization and, based on that, personalized treatment of MDD.

Associations Between Cellular Aging Markers and Metabolic Syndrome: Findings From the CARDIA Study

Background

Metabolic syndrome (MetS) is thought to promote biological aging, which might lead to cardiovascular and aging-related complications. This large-scale study investigated longitudinal relationships between MetS, its components, and cellular aging markers: leukocyte mitochondrial DNA copy number (mtDNAcn) and telomere length (TL).

Methods

We included 989 participants from the Coronary Artery Risk Development in Young Adults Study. MtDNAcn [study year (Y) 15, Y25] and TL (Y15, Y20, Y25) were measured via quantitative polymerase chain reaction. MetS components [waist circumference, triglycerides, high-density lipoprotein (HDL) cholesterol, systolic blood pressure, and fasting glucose] were determined (Y15, Y20, Y25). Generalized estimated equation and linear regression models, adjusting for sociodemographics and lifestyle, were used to examine associations between MetS and cellular aging at all time points, baseline MetS and 10-year changes in cellular aging, baseline cellular aging and 10-year changes in MetS, and 10-year changes in MetS and 10-year changes in cellular aging.

Results

MtDNAcn and TL were negatively associated with age [mtDNAcn unstandardized β (B) = -4.76; P < 0.001; TL B = -51.53; P < 0.001] and positively correlated (r = 0.152; P < 0.001). High triglycerides were associated with low mtDNAcn and low HDL cholesterol with short TL. Greater Y15 waist circumference (B = -7.23; P = 0.05), glucose (B = -13.29; P = 0.001), number of metabolic dysregulations (B = -7.72; P = 0.02), and MetS (B = -28.86; P = 0.006) predicted greater 10-year decrease in mtDNAcn but not TL. The 10-year increase in waist circumference was associated with 10-year telomere attrition (B = -27.61; P = 0.04).

Conclusions

Our longitudinal data showed that some metabolic dysregulations were associated with mtDNAcn and TL decreases, possibly contributing to accelerated cellular aging but not the converse.

Sterol 27-Hydroxylase Polymorphism Significantly Associates With Shorter Telomere, Higher Cardiovascular and Type-2 Diabetes Risk in Obese Subjects

BACKGROUND/OBJECTIVES

The pathologic relationship linking obesity and lipid dismetabolism with earlier onset of aging-related disorders, including cardiovascular disease (CVD) and type-2 diabetes (T2D), is not fully elucidate. Chronic inflammatory state, in obese individuals, may accelerate cellular aging. However, leukocyte telomere length (LTL), the cellular biological aging indicator, is elusively linked with obesity. Recent studies indicate that sterol 27-hydroxylase (CYP27A1) is an emerging antiatherogenic enzyme, that, by converting extrahepatic cholesterol to 27-hydroxycholesterol, facilitates cholesterol removal via high-density lipoprotein-cholesterol (HDL-C). We tested the hypothesis that obese subjects who carry at least three copies of CYP27A1 low-hydroxylation (LH) activity genome-wide-validated alleles (rs4674345A, rs1554622A, and rs4674338G) present premature aging, as reflected in shorter LTL and higher levels of CVD/T2D risk factors, including reduced HDL-C.

SUBJECTS/METHODS

Obese subjects from SPHERE project {n = 1,457; overweight [body mass index (BMI) 25-30 kg/m²] 65.8% and severe-obese (BMI > 30 kg/m²) 34.2%} were characterized for the presence from 0 to 6 LH-CYP27A1 allele copy number. Univariate and multivariable sex-age-smoking-adjusted linear-regression models were performed to compare CVD/T2D risk factors and biological aging (LTL) in relation to the combined BMI-LH groups: overweight-LH: 0-2, overweight-LH: 3-6, severe-obese-LH: 0-2, and severe-obese-LH: 3-6.

RESULTS

Higher LTL attrition was found in severe-obese than overweight individuals (p < 0.001). Multivariable model reveals that among severe-obese patients those with LH: 3-6 present higher LTL attrition than LH: 0-2 (p < 0.05). Univariate and multivariable models remarkably show that insulin resistance is higher both in overweight-LH: 3-6 vs overweight-LH: 0-2 (p < 0.001) and in severe-obese-LH: 3-6 vs severe-obese-LH: 0-2 (p < 0.0001), and HDL-C is lower in overweight-LH: 3-6 than overweight-LH: 0-2 (p < 0.05 and p < 001). Finally, most of the well-known (i.e., blood pressure, heart rate, waist to hip, triglycerides, and HDL-C) and novel CVD risk factors [i.e., inflammation markers (C-reactive protein, leukocytes, and chemoattractant protein-1), fibrinogen, and glucose homeostasis (i.e., insulin resistance, and glycated hemoglobin)] are substantially (p < 0.0001) altered in severe-obese-LH: 0-2 vs overweight-LH: 0-2, pointing to the fact that obesity leads to worsen the CVD/T2D risk factor profile.

CONCLUSION

Our study supports evidence that CYP27A1 genetic characterization identifies persons at higher risk to develop CVD and T2D, on which better converge preventive measures, and opens new perspectives on mechanisms that link obesity with aging-related disorders.

Investigating the associations between adiposity, life course overweight trajectories, and telomere length

Obesity may accelerate ageing through chronic inflammation. To further examine this association, we assessed current adiposity, adiposity at early adulthood and life course overweight trajectories in relation to leukocyte telomere length (LTL). We included a total of 7,008 nationally representative U.S. residents and collected information on objectively measured body mass index (BMI), waist circumference and percent body fat. BMI at age 25 and overweight trajectories were assessed using self-reported history. Leukocyte telomere length (LTL) relative to a standard DNA reference (T/S ratio) was quantified by polymerase chain reaction (PCR). Linear regression models were used to examine the difference in LTL across adiposity measures at examination, BMI at age 25, and overweight trajectories. A 0.2% decrease in telomere length (95% CI:−0.3 to −0.07%) was observed for every kg/m2 increase in BMI, whereas a unit increase in waist circumference (cm) and percent body fat contributed to a 0.09% and 0.01% decrease in LTL, respectively. Higher BMI and being obese at age 25 contributed to lower LTL at older ages. Associations between weight loss through life course and LTL were observed, which further marked the importance of life course adiposity dynamics as a determinant of ageing.

Depressive and anxiety disorders and short leukocyte telomere length: mediating effects of metabolic stress and lifestyle factors

BACKGROUND

Depressive and anxiety disorders are associated with shorter leukocyte telomere length (LTL), an indicator of cellular aging. It is, however, unknown which pathways underlie this association. This study examined the extent to which lifestyle factors and physiological changes such as inflammatory or metabolic alterations mediate the relationship.

METHOD

We applied mediation analysis techniques to data from 2750 participants of the Netherlands Study of Depression and Anxiety. LTL was assessed using quantitative polymerase chain reaction. Independent variables were current depressive (30-item Inventory of Depressive Symptoms - Self Report) and anxiety (21-item Beck's Anxiety Inventory) symptoms and presence of a depressive or anxiety disorder diagnosis based on DSM-IV; mediator variables included physiological stress systems, metabolic syndrome components and lifestyle factors.

RESULTS

Short LTL was associated with higher symptom severity (B = -2.4, p = 0.002) and current psychiatric diagnosis (B = -63.3, p = 0.024). C-reactive protein, interleukin-6, waist circumference, triglycerides, high-density lipoprotein cholesterol and cigarette smoking were significant mediators in the relationship between psychopathology and LTL. When all significant mediators were included in one model, the effect sizes of the relationships between LTL and symptom severity and current diagnosis were reduced by 36.7 and 32.7%, respectively, and the remaining direct effects were no longer significant.

CONCLUSIONS

Pro-inflammatory cytokines, metabolic alterations and cigarette smoking are important mediators of the association between depressive and anxiety disorders and LTL. This calls for future research on intervention programs that take into account lifestyle changes in mental health care settings.

Telomere length change plateaus at 4 years of age in Latino children: associations with baseline length and maternal change

Telomeres are the protective complexes at the end of chromosomes, required for genomic stability. Little is known about predictors of attrition in young children or the relationship between parental and child patterns of telomere change. Telomere length was assessed twice over one year, at 4 and at 5 years of age, in Latino preschool children (n = 77) and their mothers (n = 70) in whole blood leukocytes. Maternal and child rates of attrition during the same time period were compared in 70 mother-child pairs. More children showed lengthened telomeres over one year compared to their mothers and very few children showed attrition (2.6 %). Approximately 31 % of children and 16 % of mothers displayed lengthening over one year while 66 % of children showed maintenance in contrast with 74 % of mothers. The strongest predictor for child telomere length change was child's baseline telomere length (r = -0.61, p < 0.01). Maternal rate of change was associated with child rate of change (r = 0.33, p < 0.01). After controlling for child baseline telomere length, the relationship between child and maternal rate of change trended towards significance (Coeff = 0.20, 95 % CI -0.03 to 0.43; p = 0.08). We found primarily maintenance and lengthening from 4 to 5 years of age in children, with minimal telomere attrition, indicating that most of the telomere loss happens in the first 4 years, plateauing by age 4. Lastly, we found close to 10 % of the variance in rate of change in children shared by mothers. While some of this shared variance is genetic, there are likely environmental factors that need to be further identified that impact rate of telomere length change.

Local fat treatments: classification proposal

The poor understanding of the real, intimate action mechanisms behind any aesthetic procedures is a huge problem for many Aesthetic physicians. In addition, nomenclature of and regarding any procedure has become a true barrier when speaking about medical knowledge in the Aesthetic Medicine field since marketing and science often collide one another. Medical procedures for localized fat reduction are very different from each other and it is, at least, inaccurate to refer to all of them plainly as "fat reduction methods." A specific classification has become urgent and its categories should be able to imply what each method entails. For this classification proposal, "reversibility," "membrane disruption or inflammation," and "action selectivity," have been the selected criteria.

In utero growth restriction and catch-up adipogenesis after developmental di (2-ethylhexyl) phthalate exposure cause glucose intolerance in adult male rats following a high-fat dietary challenge

Phthalates impact adipocyte morphology in vitro, but the sex-specific adipogenic signature immediately after perinatal di(2-ethylhexyl) phthalate (DEHP) exposure and adulthood physiology following a high-fat (HF) dietary challenge are unknown. In the current study, pregnant and lactating dams received DEHP (300 mg/kg body weight) or oil. At weaning [postnatal day (PND) 21], adipose tissue was sampled for real-time polymerase chain reaction. The remaining offspring consumed a control or HF diet. DEHP decreased % fat in males at birth from 13.9%±0.2 to 11.8%±0.6 (mean±S.E.M.), representing a 15.1% decrease in fat by DEHP, and these males caught up in adiposity to controls by PND21. Adult DEHP-exposed males had a 27.5% increase in fat (12.5%±0.9% in controls vs. 15.9%±1.5% in the DEHP group); adipocyte perimeter was increased as well, with fewer small/medium-sized adipocytes, and decreased cell number compared to oil controls. HF diet intake in DEHP-exposed males further increased male energy intake and body weight and led to glucose intolerance. In PND21 males, DEHP increased the expression of adipogenic markers (Pparg1, Cebpa, Adipoq, Ppard, Fabp4, Fasn, Igf1), decreased Lep, and decreased markers of mesenchymal stem cell commitment to the adipogenic lineage (Bmp2, Bmp4, Stat1, Stat5a) compared to oil controls. These data suggest that DEHP may decrease the adipocyte pool at birth, which initially increases adaptive adipocyte maturation and lipid accumulation, but leads to adipose tissue dysfunction in adulthood, decreasing the capacity to adapt to a HF diet, and leading to systemic glucose intolerance.

Effect of obesity on telomere length: Systematic review and meta-analysis

OBJECTIVE

The main objective of this systematic review is to assess the effects of obesity on telomere length.

METHODS

The following databases were searched: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), LILACS, SPORTdiscus, and Web of Science from inception to August 2014. The search was performed using the following combinations of terms: telomere AND "overweight" OR "obesity" OR "adiposity," without language restriction.

RESULTS

Sixty-three original studies were included in this systematic review, comprising 119,439 subjects. Thirty-nine studies showed either weak or moderate correlation between obesity and telomere length; however, they showed an important heterogeneity.

CONCLUSIONS

There is a tendency toward demonstrating negative correlation between obesity and telomere length. The selected studies showed weak to moderate correlation for the main search, and there was an important heterogeneity. For this reason, the causal relationship of obesity and telomere length remains open. Additional controlled longitudinal studies are needed to investigate this issue.

Dyslipidemia and chronic inflammation markers are correlated with telomere length shortening in Cushing's syndrome

Introduction

Cushing’s syndrome (CS) increases cardiovascular risk (CVR) and adipocytokine imbalance, associated with an increased inflammatory state. Telomere length (TL) shortening is a novel CVR marker, associated with inflammation biomarkers. We hypothesized that inflammatory state and higher CVR in CS might be related to TL shortening, as observed in premature aging.

Aim

To evaluate relationships between TL, CVR and inflammation markers in CS.

Methods

In a cross-sectional study, 77 patients with CS (14 males, 59 pituitary-, 17 adrenal- and 1 ectopic-origin; 21 active disease) and 77 age-, gender-, smoking-matched controls were included. Total white blood cell TL was measured by TRF-Southern technique. Clinical data and blood samples were collected (lipids, adrenal function, glucose). Adiponectin, interleukin-6 (IL6) and C-reactive protein (CRP) were available in a subgroup of patients (n=32). Correlations between TL and clinical features were examined and multiple linear regression analysis was performed to investigate potential predictors of TL.

Results

Dyslipidemic CS had shorter TL than non-dyslipidemic subjects (7328±1274 vs 7957±1137 bp, p<0.05). After adjustment for age and body mass index, cured and active CS dyslipidemic patients had shorter TL than non-dyslipidemic CS (cured: 7187±1309 vs 7868±1104; active: 7203±1262 vs 8615±1056, respectively, p<0.05). Total cholesterol and triglycerides negatively correlated with TL (r-0.279 and -0.259, respectively, p<0.05), as well as CRP and IL6 (r-0.412 and -0.441, respectively, p<0.05). No difference in TL according the presence of other individual CVR factors (hypertension, diabetes mellitus, obesity) were observed in CS or in the control group. Additional TL shortening was observed in dyslipidemic obese patients who were also hypertensive, compared to those with two or less CVR factors (6956±1280 vs 7860±1180, respectively, p<0.001). Age and dyslipidemia were independent negative predictors of TL.

Conclusion

TL is shortened in dyslipidemic CS patients, further worse if hypertension and/or obesity coexist and is negatively correlated with increased inflammation markers. Increased lipids and a “low” grade inflammation may contribute to TL shortening and consequently to premature ageing and increased morbidity in CS.

The influence of the telomere-telomerase system on diabetes mellitus and its vascular complications

INTRODUCTION

The telomere-telomerase system plays an important role in the pathogenesis and disease progression of diabetes mellitus as well as in its vascular complications. Recent studies suggest that telomere shortening and abnormal telomerase activity occur in patients with diabetes mellitus, and targeting the telomere-telomerase system has become a prospective treatment for diabetes mellitus and its vascular complications. This review highlights the significance of the telomere-telomerase system and supports its role as a possible therapeutic target for patients with diabetes mellitus and its vascular complications Areas covered: This review covers the advances in understanding the telomere-telomerase system over the last 30 years and its significance in diabetes mellitus. In addition, it provides knowledge regarding the significance of the telomere-telomerase system in diabetes mellitus and its vascular complications as well as its role and mechanisms in oxidative stress, cell therapy and antioxidant activity Expert opinion: The telomere-telomerase system may be a potential therapeutic target that can protect against DNA damage and apoptosis in patients with diabetes mellitus and its vascular complications. DNA damage and apoptosis are associated with oxidative stress and are involved in the dysfunction of pancreatic β cells, insulin resistance, and its vascular complications. Abnormalities in the telomere-telomerase system may be associated with diabetes mellitus and its vascular complications. Therapies targeting telomere-telomerase system, telomerase reverse transcriptase transfection and alterative telomere lengthening must be identified before gene therapy can commence.

Changes in markers of oxidative stress and DNA damage in human visceral adipose tissue from subjects with obesity and type 2 diabetes

AIMS

In the past 30 years, prevalence of obesity has almost trebled resulting in an increased incidence of type 2 diabetes mellitus and other co-morbidities. Visceral adipose tissue is believed to play a vital role, but underlying mechanisms remain unclear. Our aim was to investigate changes in markers of oxidative damage in human visceral adipose tissue to determine levels of oxidative burden that may be attributed to obesity and/or diabetes.

METHODS

Visceral adipose tissue samples from 61 subjects undergoing abdominal surgery grouped as lean, obese and obese with type 2 diabetes mellitus, were examined using 3 different markers of oxidative stress. Malondialdehyde (MDA) concentration was measured as a marker of lipid peroxidation, telomere length and Comet assay as markers of oxidative DNA damage.

RESULTS

No significant difference in MDA concentration, telomere length and DNA damage was observed between groups, although longer telomere lengths were seen in the obese with diabetes group compared to the obese group (P<0.05). Lower MDA concentration and longer telomere length were seen in subjects with diabetes compared to those without (P<0.05). DNA damage, analysed via Comet assay, was significantly lower in subjects with diabetes compared to those without (P<0.05).

CONCLUSION

A paradoxical decrease in oxidative stress and DNA damage was observed in samples from subjects with type 2 diabetes mellitus. Further work is required to investigate this further, however this phenomenon may be due to an up regulation of antioxidant defences in adipose tissue.

Cellular aging in depression: Permanent imprint or reversible process?: An overview of the current evidence, mechanistic pathways, and targets for interventions

Depression might be associated with accelerated cellular aging. However, does this result in an irreversible state or is the body able to slow down or recover from such a process? Telomeres are DNA-protein complexes that protect the ends of chromosomes and generally shorten with age; and therefore index cellular aging. The majority of studies indicate that persons with depression have shorter leukocyte telomeres than similarly aged non-depressed persons, which may contribute to the observed unfavorable somatic health outcomes in the depressed population. Some small-scale preliminary studies raise the possibility that behavioral or pharmacological interventions may either slow down or else reverse this accelerated telomere shortening, possibly through increasing the activity of the telomere-lengthening enzyme telomerase. This paper covers the current state of evidence in the relationship between depression and the telomere-telomerase system and debates whether depression-related cellular aging should be considered a reversible process or permanent damage.

Developmental ORIgins of Healthy and Unhealthy AgeiNg: the role of maternal obesity--introduction to DORIAN

Europe has the highest proportion of elderly people in the world. Cardiovascular disease, type 2 diabetes, sarcopenia and cognitive decline frequently coexist in the same aged individual, sharing common early risk factors and being mutually reinforcing. Among conditions which may contribute to establish early risk factors, this review focuses on maternal obesity, since the epidemic of obesity involves an ever growing number of women of reproductive age and children, calling for appropriate studies to understand the consequences of maternal obesity on the offspring's health and for developing effective measures and policies to improve people's health before their conception and birth. Though the current knowledge suggests that the long-term impact of maternal obesity on the offspring's health may be substantial, the outcomes of maternal obesity over the lifespan have not been quantified, and the molecular changes induced by maternal obesity remain poorly characterized. We hypothesize that maternal insulin resistance and reduced placental glucocorticoid catabolism, leading to oxidative stress, may damage the DNA, either in its structure (telomere shortening) or in its function (via epigenetic changes), resulting in altered gene expression/repair, disease during life, and pathological ageing. This review illustrates the background to the EU-FP7-HEALTH-DORIAN project.

Role of epicardial adipose tissue in coronary artery disease in non-obese patients

BACKGROUND

Epicardial adipose tissue (EAT) surrounding the heart may contribute to the development of coronary artery disease (CAD) through its local secretion of adipocytokines. Although the quantity of EAT is associated with obesity and metabolic syndrome, the role of EAT in the development of CAD in non-obese patients remains to be determined.

METHODS

This study included 41 patients with CAD who underwent coronary artery bypass graft surgery and 28 patients without CAD who underwent other cardiac surgery. EAT volume was measured by 64-slice multi-detector computed tomography before the surgery. We obtained pericardial fluid and epicardial and subcutaneous adipose tissue samples at the surgery. We investigated the relationship between EAT volume and adiponectin levels in pericardial fluid and incident CAD in patients with and without obesity (body mass index>25 kg/m(2)).

RESULTS

There was no significant difference in EAT volume between obese patients with and without CAD (55.5 ± 40.2 mL vs. 40.1 ± 19.7 mL, p=0.323). However, EAT volume was significantly greater in non-obese patients with CAD compared to those without CAD (35.0 ± 18.8 mL vs. 15.7 ± 11.0 mL, p<0.001). Adiponectin concentrations in pericardial fluid were significantly lower in non-obese patients with CAD compared to those without CAD (2.7 ± 2.0 μg/mL vs. 4.3 ± 3.7 μg/mL, p=0.049), whereas the adiponectin levels were decreased in obese patients regardless of the presence of CAD. Non-obese patients with CAD had significantly larger size adipocytes in EAT but not subcutaneous adipose tissue compared to those without CAD. Multiple logistic regression analysis showed that increased EAT volume was independently associated with incident CAD in non-obese patients.

CONCLUSION

Increased EAT may play a crucial role in development of CAD through impairment of adiponectin secretion in non-obese patients.

Adipocyte telomere length associates negatively with adipocyte size, whereas adipose tissue telomere length associates negatively with the extent of fibrosis in severely obese women

Telomere length can be considered as a biological marker for cell proliferation and aging. Obesity is associated with adipocyte hypertrophy and proliferation as well as with shorter telomeres in adipose tissue. As adipose tissue is a mixture of different cell types and the cellular composition of adipose tissue changes with obesity, it is unclear what determines telomere length of whole adipose tissue. We aimed to investigate telomere length in whole adipose tissue and isolated adipocytes in relation to adiposity, adipocyte hypertrophy and adipose tissue inflammation and fibrosis. Telomere length was measured by real-time PCR in visceral adipose tissue, and isolated adipocytes of 21 obese women with a waist ranging from 110 to 147 cm and age from 31 to 61 years. Telomere length in adipocytes was shorter than in whole adipose tissue. Telomere length of adipocytes but not whole adipose tissue correlated negatively with waist and adipocyte size, which was still significant after correction for age. Telomere length of whole adipose tissue associated negatively with fibrosis as determined by collagen content. Thus, in extremely obese individuals, adipocyte telomere length is a marker of adiposity, whereas whole adipose tissue telomere length reflects the extent of fibrosis and may indicate adipose tissue dysfunction.