Metabolic Differences between Subcutaneous and Visceral Adipocytes Differentiated with an Excess of Saturated and Monounsaturated Fatty Acids

Ethnic differences in CT derived abdominal body composition measures: a comparative retrospect pilot study between European and Inuit study population

Understanding ethnic variations in body composition is crucial for assessing health risks. Universal models may not suit all ethnicities, and there is limited data on the Inuit population. This study aimed to compare body composition between Inuit and European adults using computed tomography (CT) scans and to investigate the influence of demographics on these measurements. A retrospective analysis was conducted on 50 adults (29 Inuit and 21 European) who underwent standard trauma CT scans. Measurements focused on skeletal muscle index (SMI), various fat indices, and densities at the third lumbar vertebra level, analyzed using the Wilcoxon-Mann-Whitney test and multiple linear regression. Inuit women showed larger fat tissue indices and lower muscle and fat densities than European women. Differences in men were less pronouncehd, with only Intramuscular fat density being lower among Inuit men. Regression indicated that SMI was higher among men, and skeletal muscle density decreased with Inuit ethnicity and age, while visceral fat index was positively associated with age. This study suggests ethnic differences in body composition measures particularly among women, and indicates the need for Inuit-specific body composition models. It higlights the importance of further research into Inuit-specific body composition measurements for better health risk assessment.

Mechanobiology of Adipocytes

The growing obesity epidemic necessitates increased research on adipocyte and adipose tissue function and disease mechanisms that progress obesity. Historically, adipocytes were viewed simply as storage for excess energy. However, recent studies have demonstrated that adipocytes play a critical role in whole-body homeostasis, are involved in cell communication, experience forces in vivo, and respond to mechanical stimuli. Changes to the adipocyte mechanical microenvironment can affect function and, in some cases, contribute to disease. The aim of this review is to summarize the current literature on the mechanobiology of adipocytes. We reviewed over 100 papers on how mechanical stress is sensed by the adipocyte, the effects on cell behavior, and the use of cell culture scaffolds, particularly those with tunable stiffness, to study adipocyte behavior, adipose cell and tissue mechanical properties, and computational models. From our review, we conclude that adipocytes are responsive to mechanical stimuli, cell function and adipogenesis can be dictated by the mechanical environment, the measurement of mechanical properties is highly dependent on testing methods, and current modeling practices use many different approaches to recapitulate the complex behavior of adipocytes and adipose tissue. This review is intended to aid future studies by summarizing the current literature on adipocyte mechanobiology.

Adipose organ dysfunction and type 2 diabetes: Role of nitric oxide

Adipose organ, historically known as specialized lipid-handling tissue serving as the long-term fat depot, is now appreciated as the largest endocrine organ composed of two main compartments, i.e., subcutaneous and visceral adipose tissue (AT), madding up white and beige/brown adipocytes. Adipose organ dysfunction manifested as maldistribution of the compartments, hypertrophic, hypoxic, inflamed, and insulin-resistant AT, contributes to the development of type 2 diabetes (T2D). Here, we highlight the role of nitric oxide (NO·) in AT (dys)function in relation to developing T2D. The key aspects determining lipid and glucose homeostasis in AT depend on the physiological levels of the NO· produced via endothelial NO· synthases (eNOS). In addition to decreased NO· bioavailability (via decreased expression/activity of eNOS or scavenging NO·), excessive NO· produced by inducible NOS (iNOS) in response to hypoxia and AT inflammation may be a critical interfering factor diverting NO· signaling to the formation of reactive oxygen and nitrogen species, resulting in AT and whole-body metabolic dysfunction. Pharmacological approaches boosting AT-NO· availability at physiological levels (by increasing NO· production and its stability), as well as suppression of iNOS-NO· synthesis, are potential candidates for developing NO·-based therapeutics in T2D.

Fetal programming effect of rumen-protected methionine on primiparous Angus × Simmental offspring's performance and skeletal muscle gene expression

Primiparous Angus × Simmental dams (n = 22) with an average body weight (BW) of 449 ± 32 kg of BW were divided based on two nutritional treatments: control (CTRL) and rumen-protected methionine (RPM). The control group received bermudagrass hay, corn gluten, and soybean hulls pellets supplementation (base diet); whereas the RPM group received the base diet in addition to 0.07% of DM of RPM at a fixed rate during the last trimester of gestation and the first ~80 d of lactation, in which calves (n = 17) were early weaned. Only male calves were included in this study. After weaning, calves born to RPM dams also received RPM from weaning (day 1) to day 100. Blood sampling and skeletal muscle biopsies for subsequent quantitative polymerase chain reaction (PCR) analysis were conducted on days 1, 25, 50, and 100 on calves. Quantitative PCR data were analyzed using GLIMMIX, and blood metabolites concentrations, BW, and body condition score (BCS) were analyzed using the MIXED procedure of SAS. There was no difference in maternal BW and BCS between treatments. Glucose and blood metabolites that served as biomarkers for liver health (e.g., aspartate transaminase, albumin, alkaline phosphatase, and alanine transaminase) were in the normal levels for all calves (P > 0.40). Calves in the RPM group had a greater expression of adipogenic genes (e.g., PPARG, LPL, and CEBPD) at day 100 compared with CTRL (P < 0.01). In addition, DNA methylation (DNMT1) and oxidative stress-related genes (SOD2 and NOS3) in the RPM group were upregulated at day 100 compared with CTRL (P < 0.01). These results may suggest that calves born to primiparous dams exposed to RPM supplementation are more prone to develop greater adipose tissue than CTRL calves. Furthermore, RPM supplementation may improve methylation processes, as shown by the upregulation of DNMT1. The results shown in our study aim at expanding the knowledge on fetal programming and early-life growth and development of beef cattle under supplementation with RPM.

Age-related changes in adipose tissue metabolomics and inflammation, cardiolipin metabolism, and ferroptosis markers in female aged rat model

Aging adipose tissue exhibits elevated inflammation and oxidative stress that are major sources of age-related metabolic dysfunction. However, the exact metabolic changes associated with inflammation and oxidative stress are unclear. To address this topic, we assessed variation in metabolic phenotypes of adipose tissue from 18 months adult sedentary (ASED), 26 months old sedentary (OSED), and 8 months young sedentary (YSED). The results of metabolomic analysis showed that ASED and OSED group had higher palmitic acid, elaidic acid, 1-heptadecanol, and α-tocopherol levels than YSED, but lower sarcosine levels. Furthermore, stearic acid was specifically elevated in ASED compared with YSED. Cholesterol was upregulated specifically in the OSED group compared with YSED, whereas linoleic acid was downregulated. In addition, ASED and OSED had more inflammatory cytokines, lower antioxidant capacity, and higher expression of ferroptosis-related genes than YSED. Moreover, mitochondrial dysfunction associated with abnormal cardiolipin synthesis was more pronounced in the OSED group. In conclusion, both ASED and OSED can affect the FA metabolism and increase oxidative stress in adipose tissue, leading to inflammation. In particular, linoleic acid content specifically decreases in OSED, which associated with abnormal cardiolipin synthesis and mitochondrial dysfunction in adipose tissue.

Special Issue: Lipid Metabolism, Adipogenesis and Fat Tissue Metabolism: Gene Regulation

Lipid metabolism is pivotal in controlling energy homeostasis [...].

Inflammatory crosstalk between saturated fatty acids and gut microbiota-white adipose tissue axis

PURPOSE

High-fat diets have different metabolic responses via gut dysbiosis. In this review, we discuss the complex interaction between the intake of long- and medium-chain saturated fatty acids (SFAs), gut microbiota, and white adipose tissue (WAT) dysfunction, particularly focusing on the type of fat.

RESULTS

The evidence for the impact of dietary SFAs on the gut microbiota-WAT axis has been mostly derived from in vitro and animal models, but there is now also evidence emerging from human studies. Most current reports show that, in response to high long- and medium-chain SFA diets, WAT functions are altered and can be modulated from microbial metabolites in several manners; and it appears to be also modified under conditions of obesity. SFAs overconsumption can reduce bacterial content and disrupt the gut environment. Both long- and medium-chain SFAs may contribute to proinflammatory cytokines release and TLR4 cascade signaling, either by regulation of endotoxemia markers or myristoylated protein. Palmitic and stearic acids have pathological effects on the intestinal epithelium, microbes, and inflammatory and lipogenic WAT profiles. While myristic and lauric acids display somewhat controversial outcomes, from probiotic effects and contribution to weight loss to cardiometabolic alterations from WAT inflammation.

CONCLUSION

Identifying an interference of distinct types of SFA in the binomial gut microbiota-WAT may elucidate essential mechanisms of metabolic endotoxemia, which may be the key to triggering obesity, innovating the therapeutic tools for this disease.

Developmental programming: Adipose depot-specific regulation of non-coding RNAs and their relation to coding RNA expression in prenatal testosterone and prenatal bisphenol-A -treated female sheep

Inappropriate developmental exposure to steroids is linked to metabolic disorders. Prenatal testosterone excess or bisphenol A (BPA, an environmental estrogen mimic) leads to insulin resistance and adipocyte disruptions in female lambs. Adipocytes are key regulators of insulin sensitivity. Metabolic tissue-specific differences in insulin sensitivity coupled with adipose depot-specific changes in key mRNAs, were previously observed with prenatal steroid exposure. We hypothesized that depot-specific changes in the non-coding RNA (ncRNA) - regulators of gene expression would account for the direction of changes seen in mRNAs. Non-coding RNA (lncRNA, miRNA, snoRNA, snRNA) from various adipose depots of prenatal testosterone and BPA-treated animals were sequenced. Adipose depot-specific changes in the ncRNA that are consistent with the depot-specific mRNA expression in terms of directionality of changes and functional implications in insulin resistance, adipocyte differentiation and cardiac hypertrophy were found. Importantly, the adipose depot-specific ncRNA changes were model-specific and mutually exclusive, suggestive of different regulatory entry points in this regulation.

Translational characterization of the temporal dynamics of metabolic dysfunctions in liver, adipose tissue and the gut during diet-induced NASH development in Ldlr-/-.Leiden mice

Background

NAFLD progression, from steatosis to inflammation and fibrosis, results from an interplay of intra- and extrahepatic mechanisms. Disease drivers likely include signals from white adipose tissue (WAT) and gut. However, the temporal dynamics of disease development remain poorly understood.

Methods

High-fat-diet (HFD)-fed Ldlr-/-.Leiden mice were compared to chow-fed controls. At t = 0, 8, 16, 28 and 38w mice were euthanized, and liver, WAT depots and gut were analyzed biochemically, histologically and by lipidomics and transcriptomics together with circulating factors to investigate the sequence of pathogenic events and organ cross-talk during NAFLD development.

Results

HFD-induced obesity was associated with an increase in visceral fat, plasma lipids and hyperinsulinemia at t = 8w, along with increased liver steatosis and circulating liver damage biomarkers. In parallel, upstream regulator analysis predicted that lipid catabolism regulators were deactivated and lipid synthesis regulators were activated. Subsequently, hepatocyte hypertrophy, oxidative stress and hepatic inflammation developed. Hepatic collagen accumulated from t = 16 w and became pronounced at t = 28-38 w. Epididymal WAT was maximally hypertrophic from t = 8 w, which coincided with inflammation development. Mesenteric and subcutaneous WAT hypertrophy developed slower and did not appear to reach a maximum, with minimal inflammation. In gut, HFD significantly increased permeability, induced a shift in microbiota composition from t = 8 w and changed circulating gut-derived metabolites.

Conclusion

HFD-fed Ldlr-/-.Leiden mice develop obesity, dyslipidemia and insulin resistance, essentially as observed in obese NAFLD patients, underlining their translational value. We demonstrate that marked epididymal-WAT inflammation, and gut permeability and dysbiosis precede the development of NAFLD stressing the importance of a multiple-organ approach in the prevention and treatment of NAFLD.

Diet containing stearic acid increased food intake in mice by reducing serum leptin compared with oleic acid

In today's society, obesity is becoming increasingly serious, and controlling food intake and maintaining weight balance have become increasingly important. Here, we found that a stearic acid diet can increase food intake without causing obesity in mice compared with an oleic acid diet. Stearic acid increases food intake in mice by reducing serum leptin and increasing NPY neuronal excitability through the JAK2/STAT3 pathway. The impaired anorexic effect of leptin is probably due to repressive cholesterol-oxysterol-LXR-α/SREBP-1c-mediated leptin expression in mouse iWAT. At the same time, we found that stearic acid was not only poorly absorbed by itself in the small intestine but also reduced the entire absorption system of the small intestine. In conclusion, we have proven that a stearic acid diet can increase food intake in mice and avoid obesity, but whether a stearic acid diet could cause adverse reactions in the body remains to be studied.

Poor glycaemic control and ectopic fat deposition mediates the increased risk of non-alcoholic steatohepatitis in high-risk populations with type 2 diabetes: Insights from Bayesian-network modelling

BACKGROUND

An estimated 55.5% and 37.3% of people globally with type 2 diabetes (T2D) will have concomitant non-alcoholic fatty liver disease (NAFLD) and the more severe fibroinflammatory stage, non-alcoholic steatohepatitis (NASH). NAFLD and NASH prevalence is projected to increase exponentially over the next 20 years. Bayesian Networks (BNs) offer a powerful tool for modelling uncertainty and visualising complex systems to provide important mechanistic insight.

METHODS

We applied BN modelling and probabilistic reasoning to explore the probability of NASH in two extensively phenotyped clinical cohorts: 1) 211 participants with T2D pooled from the MODIFY study & UK Biobank (UKBB) online resource; and 2) 135 participants without T2D from the UKBB. MRI-derived measures of visceral (VAT), subcutaneous (SAT), skeletal muscle (SMI), liver fat (MRI-PDFF), liver fibroinflammatory change (liver cT1) and pancreatic fat (MRI-PDFF) were combined with plasma biomarkers for network construction. NASH was defined according to liver PDFF >5.6% and liver cT1 >800ms. Conditional probability queries were performed to estimate the probability of NASH after fixing the value of specific network variables.

RESULTS

In the T2D cohort we observed a stepwise increase in the probability of NASH with each obesity classification (normal weight: 13%, overweight: 23%, obese: 36%, severe obesity: 62%). In the T2D and non-T2D cohorts, elevated (vs. normal) VAT conferred a 20% and 1% increase in the probability of NASH, respectively, while elevated SAT caused a 7% increase in NASH risk within the T2D cohort only. In those with T2D, reducing HbA1c from the 'high' to 'low' value reduced the probability of NASH by 22%.

CONCLUSION

Using BNs and probabilistic reasoning to study the probability of NASH, we highlighted the relative contribution of obesity, ectopic fat (VAT and liver) and glycaemic status to increased NASH risk, namely in people with T2D. Such modelling can provide insights into the efficacy and magnitude of public health and pharmacological interventions to reduce the societal burden of NASH.

The underexplored links between cancer and the internal body climate: Implications for cancer prevention and treatment

In order to effectively manage and cure cancer we should move beyond the general view of cancer as a random process of genetic alterations leading to uncontrolled cell proliferation or simply a predictable evolutionary process involving selection for traits that increase cell fitness. In our view, cancer is a systemic disease that involves multiple interactions not only among cells within tumors or between tumors and surrounding tissues but also with the entire organism and its internal "milieu". We define the internal body climate as an emergent property resulting from spatial and temporal interactions among internal components themselves and with the external environment. The body climate itself can either prevent, promote or support cancer initiation and progression (top-down effect; i.e., body climate-induced effects on cancer), as well as be perturbed by cancer (bottom-up effect; i.e., cancer-induced body climate changes) to further favor cancer progression and spread. This positive feedback loop can move the system towards a "cancerized" organism and ultimately results in its demise. In our view, cancer not only affects the entire system; it is a reflection of an imbalance of the entire system. This model provides an integrated framework to study all aspects of cancer as a systemic disease, and also highlights unexplored links that can be altered to both prevent body climate changes that favor cancer initiation, progression and dissemination as well as manipulate or restore the body internal climate to hinder the success of cancer inception, progression and metastasis or improve therapy outcomes. To do so, we need to (i) identify cancer-relevant factors that affect specific climate components, (ii) develop 'body climate biomarkers', (iii) define 'body climate scores', and (iv) develop strategies to prevent climate changes, stop or slow the changes, or even revert the changes (climate restoration).

Weizmannia coagulans BC2000 Plus Ellagic Acid Inhibits High-Fat-Induced Insulin Resistance by Remodeling the Gut Microbiota and Activating the Hepatic Autophagy Pathway in Mice

(1) Background: Ellagic acid (EA) acts as a product of gut microbiota transformation to prevent insulin resistance, which is limited by high-fat diet (HFD)-induced dysbiosis. The aim of this study was to investigate the synergistic effects and mechanisms of supplementation with the probiotic Weizmannia coagulans (W. coagulans) on the prevention of insulin resistance by EA; (2) Methods: C57BL/6J mice were divided into five groups (n = 10/group): low-fat-diet group, high-fat-diet group, EA intervention group, EA + W. coagulans BC77 group, and EA + W. coagulans BC2000 group; (3) Result: W. coagulans BC2000 showed a synergistic effect on EA's lowering insulin resistance index and inhibiting high-fat diet-induced endotoxemia. The combined effect of BC2000 and EA activated the autophagy pathway in the mouse liver, a urolithin-like effect. This was associated with altered β-diversity of gut microbiota and increased Eggerthellaceae, a potential EA-converting family. Ellagic acid treatment alone and the combined use of ellagic acid and W. coagulans BC77 failed to activate the hepatic autophagy pathway; (4) Conclusions: W. coagulans BC2000 can assist EA in its role of preventing insulin resistance. This study provides a basis for the development of EA-rich functional food supplemented with W. coagulans BC2000.

Cornus mas L. Increases Glucose Uptake and the Expression of PPARG in Insulin-Resistant Adipocytes

Cornus mas L., also known as cornelian cherry (CM), is a species that has long been cultivated in many different countries. In numerous scientific reports, cornelian cherry is used to treat numerous diseases and conditions. The presented study evaluated the effect of red and yellow Cornus mas L. extract on insulin sensitivity in adipocytes. 3T3-L1 fibroblasts as well as human SAT-derived and VAT-derived adipocytes were differentiated in vitro, and insulin resistance was induced using palmitic acid (16:0). The effect of CM fruit extract was analyzed in terms of glucose uptake and insulin signaling gene expression. In the glucose uptake test after insulin stimulation, a significant increase in glucose uptake was demonstrated in cells treated with CM fruit extracts. Furthermore, CM fruit extracts increased the expression of insulin signaling genes in adipocytes stimulated with insulin in control cells and adipocytes treated with CM extract. Additionally, a significant increase in peroxisome proliferator activated receptor gamma (PPARG) expression was observed in cells supplemented with CM extract. In conclusion, studies have shown that CM fruits can overcome insulin resistance and thus they have a positive effect on cell metabolism.

The Phenotype of the Adipocytes Derived from Subcutaneous and Visceral ADMSCs Is Altered When They Originate from Morbidly Obese Women: Is There a Memory Effect?

Adipose tissue is an abundant source of mesenchymal stem cells (ADMSCs). Evidence has suggested that depot-specific ADMSCs (obtained from subcutaneous or visceral adipose tissue-subADMSCs or visADMSCs, respectively) account for differential responses of each depot to metabolic challenges. However, little is known about the phenotype and changes in metabolism of the adipocytes derived from ADMSCs of obese individuals. Therefore, we investigated the phenotypic and metabolic characteristics, particularly the lipid profile, of fully differentiated adipocytes derived from ADMSCs of lean and obese (with/without metabolic syndrome) postmenopausal women. We observed a depot-specific pattern, with more pronounced changes present in the adipocytes obtained from subADMSCs. Namely, chronic oversupply of fatty acids (present in morbid obesity) triggered an increase in CD36/SR-B2 and FATP4 protein content (total and cell surface), which translated to an increased LCFA influx (3H-palmitate uptake). This was associated with the accumulation of TAG and DAG in these cells. Furthermore, we observed that the adipocytes of visADMSCs origin were larger and showed smaller granularity than their counterparts of subADMSCs descent. Although ADMSCs were cultured in vitro, in a fatty acids-deprived environment, obesity significantly influenced the functionality of the progenitor adipocytes, suggesting the existence of a memory effect.

The Preliminary Evaluation of Epigenetic Modifications Regulating the Expression of IL10 in Insulin-Resistant Adipocytes

A higher level of IL10 expression in obesity and insulin resistance was observed in both human and mouse WAT. In our research, we analyzed the influence of insulin resistance on epigenetic modification within the promoter region IL10 gene and the potential influence of these modifications on its expression. Studies were performed using two cell models for the analysis: human, preadipocytes derived from adipose (visceral and subcutaneous) tissues and murine 3T3-L1 fibroblasts. We demonstrated a significant increase in the IL10 expression level, IL10 promoter region methylation, and histone 3 epigenetic modifications: H3K4me and H3K9/14ac, in insulin resistance cells (IR) from SAT cell culture. In IR cells from VAT cell culture, we observed decreased IL10 expression with a simultaneous increase of IL10 promoter region methylation. In IR cells from 3T3L1 cell culture, we observed the increased expression of IL10 as well as the decreased levels of methylation in the IL10 promoter region and histone methylation (H3K4me) and acetylation (H3K9/14ac). The presented analyses suggest a potential impact of epigenetic modifications on gene expression and a potential mutual influence of epigenetic modifications on each other or the activation of specific epigenetic regulation at a different stage of the development of insulin resistance in cells.

The structure of nutrition of Russian students as a risk factor for the development of nutritional diseases

The paper analyzes the literature data on the peculiarities of nutrition of students studying in higher educational institutions of various regions of Russia, and the risks of developing food-related diseases. They are largely associated with the adaptation of students to study at a university, the lack of self-organization skills and a lack of  knowledge in matters of rational nutrition. The actual nutrition of  students, on the one hand, is characterized by a lack of macronutrients and micronutrients intake, on the other hand, by excessive consumption of substances that contribute to the development of obesity. The results of numerous studies show a general pattern of unbalanced nutrition of students in terms of the ratio of saturated and polyunsaturated fatty acids, insufficient consumption of dietary fiber, full-fledged proteins, and  excessive intake of simple carbohydrates. Dietary fiber deficiency can  lead to changes in the composition of the microbiocenosis of the digestive tract, a deficiency of omega-3 fatty acids, and consequently, the imbalance of fatty acid composition of the blood cell membrane. 20–40 % of Russian students show signs of severe hypovitaminosis, especially calciferol, which is caused not only by its deficiency in the diet, but also by physical, geographical, climatic and seasonal factors. The analysis of the content of the main minerals in students shows a sufficient content of calcium in the body, an excess of sodium and a lack of magnesium, potassium and  iron, which is due to both the composition of the food consumed and the peculiarities of the accumulation and excretion of these ions. An analysis of the actual nutrition of students shows the need for counseling young people, especially in the first years of study. The introduction of an educational program on optimal nutrition is possible through the practice of curatorial work during the adaptation of the first-year students to student’s life. 

Activation of Cx43 Hemichannels Induces the Generation of Ca2+ Oscillations in White Adipocytes and Stimulates Lipolysis

The aim of the study was to investigate the mechanisms of Ca²⁺ oscillation generation upon activation of connexin-43 and regulation of the lipolysis/lipogenesis balance in white adipocytes through vesicular ATP release. With fluorescence microscopy it was revealed that a decrease in the concentration of extracellular calcium ([Ca²⁺]_ex) results in two types of Ca²⁺ responses in white adipocytes: Ca²⁺ oscillations and transient Ca²⁺ signals. It was found that activation of the connexin half-channels is involved in the generation of Ca²⁺ oscillations, since the blockers of the connexin hemichannels-carbenoxolone, octanol, proadifen and Gap26-as well as Cx43 gene knockdown led to complete suppression of these signals. The activation of Cx43 in response to the reduction of [Ca²⁺]_ex was confirmed by TIRF microscopy. It was shown that in response to the activation of Cx43, ATP-containing vesicles were released from the adipocytes. This process was suppressed by knockdown of the Cx43 gene and by bafilomycin A1, an inhibitor of vacuolar ATPase. At the level of intracellular signaling, the generation of Ca²⁺ oscillations in white adipocytes in response to a decrease in [Ca²⁺]_ex occurred due to the mobilization of the Ca²⁺ ions from the thapsigargin-sensitive Ca²⁺ pool of IP₃R as a result of activation of the purinergic P2Y1 receptors and phosphoinositide signaling pathway. After activation of Cx43 and generation of the Ca²⁺ oscillations, changes in the expression levels of key genes and their encoding proteins involved in the regulation of lipolysis were observed in white adipocytes. This effect was accompanied by a decrease in the number of adipocytes containing lipid droplets, while inhibition or knockdown of Cx43 led to inhibition of lipolysis and accumulation of lipid droplets. In this study, we investigated the mechanism of Ca²⁺ oscillation generation in white adipocytes in response to a decrease in the concentration of Ca²⁺ ions in the external environment and established an interplay between periodic Ca²⁺ modes and the regulation of the lipolysis/lipogenesis balance.

PPARG Hypermethylation as the First Epigenetic Modification in Newly Onset Insulin Resistance in Human Adipocytes

Insulin acts by binding with a specific receptor called an insulin receptor (INSR), ending up with glucose transporter activation and glucose uptake. Insulin resistance (IR) is a state when the physiological amount of insulin is not sufficient to evoke proper action, i.e., glucose uptake. Epigenetic modifications associated with obesity and IR are some of the main mechanisms leading to IR pathogenesis. The mesenchymal stem cells of adipose tissue (subcutaneous (SAT) and visceral (VAT)) were collected during abdominal surgery. IR was induced ex vivo by palmitic acid. DNA methylation was determined at a global and site-specific level. We found higher global DNA methylation in IR adipocytes after 72 h following IR induction. Furthermore, numerous genes regulating insulin action (PPARG, SLC2A4, ADIPOQ) were hypermethylated in IR adipocytes; the earliest changes in site-specific DNA methylation have been detected for PPARG. Epigenetic changes appear to be mediated through DNMT1. DNA methylation is an important component of IR pathogenesis; the PPARG and its epigenetic modification appear to be the very first epigenetic modification in newly onset IR and are probably of the greatest importance.

Breastfeeding history and the risk of overweight and obesity in middle-aged women

BACKGROUND

The increased metabolic activity required to sustain breastfeeding and its associated milk production helps to reduce maternal fat stores accumulated during pregnancy. This study aims to assess the association between breastfeeding duration and fatness indices in middle-aged women.

METHODS

The analysis was carried out in a group of 7500 parous 55.5 ± 5.3 year old women included body mass index, body fat percentage, and waist-to-height ratio. The likelihood of excessive weight or obesity in relation to total breastfeeding time using multivariate logistic regression analyses.

RESULTS

An analysis of adjusted odds ratios did not show significant associations between breastfeeding duration and the risk of excessive weight and obesity in premenopausal women. After menopause, women who gave birth to 2 children and breastfed 1-6 and > 12 months had a lower risk of abdominal obesity (OR 0.70; 95% CI 0.50-0.99; p = 0.042; and OR 0.68; 95% CI 0.47-0.98; p = 0.039). Women who gave birth to 3 or more children and breastfed for 1-6 months, also showed a lower risk of overweight (OR 0.52; 95% CI 0.27-0.99; p = 0.047), compared to those ones that have never breastfed. There was no relationship found between the duration of lactation and the risk of excessive body fat.

CONCLUSION

Breastfeeding may have some beneficial, long-term effect on the risk of excessive weight and abdominal obesity in women.