Early life high-fat diet exposure evokes normal weight obesity

Dietary lipids shape cytokine and leptin profiles in obesity-metabolic syndrome implications: A cross-sectional study

BACKGROUND

Obesity, characterized by chronic energy imbalance and excessive adiposity, is a key component of metabolic syndrome and is associated with low-grade inflammation and altered adipokine secretion. This study aimed to evaluate the association between dietary fat consumption and its influence on interleukin (IL) and leptin levels in participants with obesity.

METHODS

Using the Asian obesity classification criteria, a cross-sectional study was conducted on 384 adults (18-59 years). Anthropometric measurements by bioelectrical impedance analyzer (BIA), blood biochemistry by colorimetric assay, inflammatory markers and hormones by ELISA test, and dietary intake were assessed by Semi-FFQ.

RESULTS

Obesity prevalence was 26.1% and 73.90% in males and females, respectively. Participants with obesity exhibited significantly higher inflammatory and hormonal marker levels. Positive correlations were observed between blood lipid, glucose, and tumor necrosis factor-α, IL-6, and leptin levels. Energy, carbohydrate, and sugar intake were positively correlated with leptin levels. High saturated fat intake was associated with increased IL-6 levels (odds ratio = 2.03, 95% confidence interval [CI] = 1.00-4.11, p < 0.047), whereas high total fat intake elevated leptin levels by 2.14-fold (95% CI = 1.12-4.10, p < 0.021) in participants with obesity.

CONCLUSIONS

This study demonstrates significant associations between dietary fat composition, inflammatory markers, and leptin levels in individuals with obesity. These findings suggest that modulating dietary fat intake can be a potential strategy for mitigating obesity-related inflammation and leptin resistance, highlighting the need for targeted nutritional interventions in obesity and metabolic syndrome management.

Dyslipidemia and hyperglycemia induce overexpression of Syndecan-3 in erythrocytes and modulate erythrocyte adhesion

Erythrocytes are important vascular components that play vital roles in maintaining vascular homeostasis, in addition to carrying oxygen. Previously, we reported that the changes in the internal milieu (e.g. hyperglycemia or hypercholesterolemia) increase erythrocyte adhesion to various extracellular matrix components, potentially through altering glycosaminoglycans (GAGs). In this study, we have investigated the expression of syndecan (Sdc) family members that could be involved in mediating cytoadherence under conditions of dyslipidemia and hyperglycemia. Among the Sdc family members analysed, we found significant overexpression of Sdc-3 in erythrocyte membranes harvested from high-fat-fed control and diabetic animals. Animal studies revealed a positive correlation between Sdc-3 expression, blood sugar levels and erythrocyte adhesion. In the human study, diabetic cohorts with body mass index >24.9 showed significantly increased expression of Sdc-3. Interestingly, blocking the Sdc-3 moiety with an anti-Sdc-3 antibody revealed that the core protein might not be directly involved in erythrocyte adhesion to fibronectin despite the GAGs bringing about adhesion. Lastly, Nano liquid chromatography-mass spectrometry/MS verified the presence of Sdc-3 in erythrocyte membranes. In conclusion, the high-fat diet and diabetes modulated Sdc-3 expression in the erythrocyte membrane, which may alter its adhesive properties and promote vascular complications.

Evaluation of amidated pectin as fat substitutes for minced chicken breast: Physicochemical properties and edible quality

An investigation was conducted to assess the gelation characteristics of amino acid amidated pectin and its subsequent influence on the quality of minced chicken breast (MCB) when employed as a lipid substitute. Through experimentation, it was evidenced that amidated pectin, such as glycine amidated pectin (AP@Gly), glutamic amidated pectin (AP@Glu), and lysine amidated pectin (AP@Lys), demonstrated superior viscosity and gelation capacity in comparison to their native pectin (PE) counterpart. In contrast to PE, amidated pectin samples exhibited the potential to form high-strength hydrogels under conditions of minimal restriction. Additionally, evaluations conducted on all samples established that MCB samples enriched with pectin and amidated pectin demonstrated superior water retention capability. Before thermal processing, MCB samples fortified with amidated pectin showcased higher hardness and L* values in comparison to PE and the control group. However, upon thermal processing, no significant divergence was found in the chroma and texture profile analysis (TPA) attributes across all MCB samples, and the electronic tongue sensory evaluation was closely aligned with the control group. This evidence substantiates the effectiveness of amidated pectin samples as viable lipid substitutes in MCB products.

Early life adverse exposures in irritable bowel syndrome: new insights and opportunities

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder worldwide. Extensive research has identified multiple factors contributing to its development, including genetic predisposition, chronic infection, gut dysbiosis, aberrant serotonin metabolism, and brain dysfunction. Recent studies have emphasized the critical role of the early life stage as a susceptibility window for IBS. Current evidence suggests that diet can heighten the risk of IBS in offspring by influencing the microbiota composition, intestinal epithelium structure, gene expression, and brain-gut axis. The use of antibiotics during pregnancy and the neonatal period disrupts the normal gut microbiota structure, aligning it with the characteristics observed in IBS patients. Additionally, early life stress impacts susceptibility to IBS by modulating TLR4, NK1, and the hypothalamic-pituitary-adrenal (HPA) axis while compromising the offspring's immune system. Formula feeding facilitates the colonization of pathogenic bacteria in the intestines, concurrently reducing the presence of probiotics. This disruption of the Th1 and Th2 cell balance in the immune system weakens the intestinal epithelial barrier. Furthermore, studies suggest that delivery mode influences the occurrence of IBS by altering the composition of gut microbes. This review aims to provide a comprehensive summary of the existing evidence regarding the impact of adverse early life exposures on IBS during pregnancy, intrapartum, and neonatal period. By consolidating this knowledge, the review enhances our understanding of the direct and indirect mechanisms underlying early life-related IBS and offers new insights and research directions from childhood to adulthood.

Knockout of TSC2 in Nav1.8+ neurons predisposes to the onset of normal weight obesity

OBJECTIVE

Obesity and nutrient oversupply increase mammalian target of rapamycin (mTOR) signaling in multiple cell types and organs, contributing to the onset of insulin resistance and complications of metabolic disease. However, it remains unclear when and where mTOR activation mediates these effects, limiting options for therapeutic intervention. The objective of this study was to isolate the role of constitutive mTOR activation in Nav1.8-expressing peripheral neurons in the onset of diet-induced obesity, bone loss, and metabolic disease.

METHODS

In humans, loss of function mutations in tuberous sclerosis complex 2 (TSC2) lead to maximal constitutive activation of mTOR. To mirror this in mice, we bred Nav1.8-Cre with TSC2fl/fl animals to conditionally delete TSC2 in Nav1.8-expressing neurons. Male and female mice were studied from 4- to 34-weeks of age and a subset of animals were fed a high-fat diet (HFD) for 24-weeks. Assays of metabolism, body composition, bone morphology, and behavior were performed.

RESULTS

By lineage tracing, Nav1.8-Cre targeted peripheral sensory neurons, a subpopulation of postganglionic sympathetics, and several regions of the brain. Conditional knockout of TSC2 in Nav1.8-expressing neurons (Nav1.8-TSC2KO) selectively upregulated neuronal mTORC1 signaling. Male, but not female, Nav1.8-TSC2KO mice had a 4-10% decrease in body size at baseline. When challenged with HFD, both male and female Nav1.8-TSC2KO mice resisted diet-induced gains in body mass. However, this did not protect against HFD-induced metabolic dysfunction and bone loss. In addition, despite not gaining weight, Nav1.8-TSC2KO mice fed HFD still developed high body fat, a unique phenotype previously referred to as 'normal weight obesity'. Nav1.8-TSC2KO mice also had signs of chronic itch, mild increases in anxiety-like behavior, and sex-specific alterations in HFD-induced fat distribution that led to enhanced visceral obesity in males and preferential deposition of subcutaneous fat in females.

CONCLUSIONS

Knockout of TSC2 in Nav1.8+ neurons increases itch- and anxiety-like behaviors and substantially modifies fat storage and metabolic responses to HFD. Though this prevents HFD-induced weight gain, it masks depot-specific fat expansion and persistent detrimental effects on metabolic health and peripheral organs such as bone, mimicking the 'normal weight obesity' phenotype that is of growing concern. This supports a mechanism by which increased neuronal mTOR signaling can predispose to altered adipose tissue distribution, adipose tissue expansion, impaired peripheral metabolism, and detrimental changes to skeletal health with HFD - despite resistance to weight gain.

Effects of magnesium picolinate, zinc picolinate, and selenomethionine co-supplementation on reproductive hormones, and glucose and lipid metabolism-related protein expressions in male rats fed a high-fat diet

This study aimed to examine the impacts of the magnesium picolinate (MgPic), zinc picolinate (ZnPic), and selenomethionine (SeMet) alone or as a combination on blood metabolites, oxidative enzymes, reproductive hormones, and glucose and lipid metabolism-related protein expressions in Wistar rats fed a high-fed diet (HFD). The rats were fed either a control, HFD, or HFD supplemented with a single (MgPic, ZnPic, SeMet) or two or three organic mineral combinations. Body weights, visceral fat, serum glucose, insulin, total cholesterol, triglycerides, leptin, malondialdehyde (MDA) concentrations as well as liver sterol regulatory element-binding protein-1c (SREBP-1c), liver X receptor alpha (LXRα), ATP citrate lyase (ACLY), fatty acid synthase (FAS), and nuclear factor kappa B (NF-κB) levels increased, while serum testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex hormone-binding globulin (SHBG), and insulin-like growth factor (IGF-1) concentrations along with liver nuclear factor erythroid 2-related factor 2 (Nrf2) levels declined in HFD rats (P < 0.05). Supplementing each organic mineral, but particularly the combination of HFD + MgPic + ZnPic + SeMet reversed the responses with various degrees. None of the organic elements alone or as a combination of two exerted a prominent effect on parameters measured. Although not additive or synergistic, the combination of all organic minerals added to HFD (HFD + MgPic + ZnPic + SeMet) provided the greatest responses.

Intake of a Chicken Protein-Based or Soy Protein-Based Diet Differentially Affects Growth Performance, Absorptive Capacity, and Gut Microbiota in Young Rats

SCOPE

Both plant and animal products provide protein for human demands. However, the effect of protein sources on the physiological responses and the composition and functions of the gut microbiota during the early stage of life have received little attention.

METHODS AND RESULTS

In the present study, chicken protein and soy protein are fed to young weaning rats for 14 days based on the AIN-93G diet formulation. The growth performance is recorded, and the morphology of the small intestine is analyzed to estimate the absorptive capacity. Shotgun metagenomic sequencing is applied to analyze the cecal microbiota. The chicken protein-based diet (CHPD) enhances growth performance and absorptive capacity in young rats compared to the soy protein-based diet (SPD). The CHPD maintains higher levels of Lactobacillus species, associated with glutathione synthesis.

CONCLUSION

The CHPD seems favorable for young growing rats in relation to growth performance and absorptive capacity, correlated with changes in the composition and functional potential of the gut microbiota.

Dietary Iron Deficiency Modulates Adipocyte Iron Homeostasis, Adaptive Thermogenesis, and Obesity in C57BL/6 Mice

BACKGROUND

Adaptive thermogenesis is an iron-demanding pathway, significantly contributing to whole-body energy expenditure. However, the effects of iron-deficient diets on adaptive thermogenesis and obesity remain unknown.

OBJECTIVES

We aimed to determine the impact of dietary iron deficiency on iron homeostasis in adipocytes, adaptive thermogenic capacity, and metabolic consequences in obesity.

METHODS

C57BL/6 male mice were assigned to either the iron-adequate (IA, 35 ppm) or the iron-deficient group (ID, 3 ppm) at weaning. Upon 8 wk of age, both IA and ID groups received an isocaloric high-fat diet (45% kcal from fat) for 10 wk, maintaining the same iron content. Mice (n = 8) were used to determine the iron status at the systemic and tissue levels and lipid metabolism and inflammatory signaling in adipose tissue. The same mice were used to evaluate cold tolerance (4°C) for 3 h. For assessing adaptive thermogenesis, mice (n = 5) received an intraperitoneal injection of β3-adrenoceptor agonist CL316243 (CL) for 5 d.

RESULTS

Compared with the IA group, the ID group had nonanemic iron deficiency, lower serum ferritin (42.8%, P < 0.01), and greater weight gain (8.67%, P < 0.05) and insulin resistance (159%, P < 0.01), partly due to reduced AMP-activated protein kinase activation (61.0%, P < 0.05). Upon cold exposure, the ID group maintained a core body temperature 2°C lower than the IA group. The ID group had lower iron content (47.0%, P < 0.01) in the inguinal adipose tissue (iWAT) than the IA group, which was associated with impaired adaptive thermogenesis. In response to CL, ID mice showed decreased heat production (P < 0.01) and defective upregulation of beige adipocyte-specific markers, including uncoupling protein 1 (41.1%, P < 0.001), transferrin receptor 1 (47.5%, P < 0.001), and mitochondrial respiratory chain complexes (P < 0.05) compared with IA mice.

CONCLUSIONS

Dietary iron deficiency deregulates iron balance in the iWAT and impairs adaptive thermogenesis, thereby escalating the diet-induced weight gain in C57BL/6 mice.

Insufficient Physical Fitness and Deficits in Basic Eating Habits in Normal-Weight Obese Children Are Apparent from Pre-School Age or Sooner

Normal-weight obesity appears to be an extended diagnosis/syndrome associated with insufficient physical fitness levels and inadequate eating habits at least from school years. However, its relation to long term health parameters in pre-school children remains unknown, even though pre-school age is crucial for the determining healthy lifelong habits. Therefore, the aim of the current study was to investigate the differences in physical fitness level and basic eating habits between normal-weight obese, normal-weight non-obese, and overweight and obese preschoolers. The research sample consisted of 188 preschoolers aged 4.0–6.9 years (M_age = 5.52 ± 0.8 year), normal-weight obese = 25; normal-weight non-obese = 143, overweight and obese = 20. Body composition was measured using bio-impedance InBody230. Six tests assessed the physical fitness level: sit-ups; standing long jump; shuttle running 4 × 5 meters; throwing with a tennis ball; multistage fitness tests; sit and reach. A four-item eating habits questionnaire for parents focusing on breakfast regularity, consumption of sweet foods and drinks, selection of food and attitude towards eating was used. A non-parametric analysis of variance and Fisher’s exact test along with suitable effect sizes were used for data processing of physical fitness tests and the basic eating habits questionnaire, respectively. Normal-weight obese children performed significantly worse (from p = 0.03 to p < 0.001, ES ω2-G = low to medium) in muscular fitness, cardiorespiratory fitness and running agility compared to normal-weight non-obese counterparts and did not significantly differ in the majority of physical fitness performance tests from overweight and obese peers. In basic eating habits, normal-weight obese boys preferred significantly more sweet foods and drinks (p = 0.003 ES = 0.35, large), while normal-weight obese girls had significantly more negative attitude towards eating (p = 0.002 ES = 0.33, large) in comparison to their normal-weight non-obese peers. Normal-weight obesity seems to develop from early childhood and is associated with low physical fitness and deficits in eating habits which might inhibit the natural necessity for physically active life from pre-school age or sooner.

Effects of Live and Pasteurized Forms of Akkermansia from the Human Gut on Obesity and Metabolic Dysregulation

Akkermansia muciniphila (A. muciniphila) is a promising probiotic candidate owing to its health-promoting properties. A previous study reported that the pasteurized form of A. muciniphila strains isolated from human stool samples had a beneficial impact on high-fat diet-induced obese mice. On the other hand, the differences in the probiotic effects between live and pasteurized A. muciniphila on the metabolism and immune system of the host are still inconclusive. This study examines the differences between the live and pasteurized forms of A. muciniphila strains on the lipid and glucose metabolism and on regulating the inflammatory immune responses using a HFD-fed obese mouse model. The animals were administered the live and pasteurized forms of two A. muciniphila strains five times per week for the entire study period of 12 weeks. Both forms of the bacterial strains improved the HFD-induced obesity and metabolic dysregulation in the mice by preventing body-weight gains after one week. In addition, they cause a decrease in the weights of the major adipose tissues, adipogenesis/lipogenesis and serum TC levels, improvement in glucose homeostasis and suppression of inflammatory insults. Furthermore, these treatments restored the damaged gut architecture and integrity and improved the hepatic structure and function in HFD-induced animals. On the other hand, for both bacterial strains, the pasteurized form was more potent in improving glucose tolerance than the live form. Moreover, specific A. muciniphila preparations with either live or pasteurized bacteria decreased the number and population (%) of splenic Treg cells (CD4+ Foxp3+) significantly in the HFD-fed animals, further supporting the anti-inflammatory properties of these bacteria.