Weight loss is more important than the diet type in improving adiponectin levels among overweight/obese adults

Exposure to 4,4'-DDE in visceral adipose tissue and weight loss in adolescents from the Teen-LABS cohort

OBJECTIVE

Dichlorodiphenyldichloroethylene (DDE), an obesogen accumulating in adipose tissue, is released into circulation with weight loss, although its impact is underexplored among adolescents. We tested the association using an integrative translational approach of epidemiological analysis among adolescents with obesity and in vitro measures exploring the impact of DDE on adipogenesis via preadipocytes.

METHODS

We included 63 participants from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort. We assessed 4,4'-DDE in visceral adipose tissue at surgery and BMI and waist circumference at surgery and 0.5, 1, 3, and 5 years after. We conducted longitudinal analysis to estimate the interaction on weight loss between DDE and time since surgery. In vitro analysis quantified adipogenic differentiation in commercial human preadipocytes exposed to 4,4'-DDE via fluorescent staining and imaging.

RESULTS

A dose-response relationship was observed, with the low-exposure group having a greater reduction in BMI during the first year compared to higher-exposure groups and showing smaller regains compared to higher-exposure groups after the first year. In vitro analysis of preadipocytes treated with 4,4'-DDE during adipogenic differentiation for 12 days showed a concentration-dependent increase in lipid accumulation.

CONCLUSIONS

DDE could contribute to weight trajectory among adolescents undergoing bariatric surgery, potentially mediated via promoted adipogenesis in preadipocytes.

The effects of vegetarian diets on glycemia and lipid parameters in adult patients with overweight and obesity: a systematic review and meta-analysis

Several randomized controlled trials have reported the effects of vegetarian diets on blood lipids and glucose homeostasis in adults, but not in overweight or obese individuals. Thus, the purpose of this study was to evaluate the effects of vegetarian diets on blood lipids and glucose homeostasis in overweight or obese adults by systematic review and meta-analysis. We searched Medline, Embase, and the Cochrane Library through October 2021. We chose to include overweight or obese patients in the studies of the vegetarian diet for metabolic control. Seven trials with a total of 783 overweight or obese adult were included in the meta-analysis. The analysis of the data revealed that the vegetarian diets significantly reduced low-density lipoprotein cholesterol (LDL-C) (WMD, -0.31; 95% CI, -0.46 to -0.16), total cholesterol (TC) (WMD, -0.37; 95% CI, -0.52 to -0.22), and HbA1c (WMD (%), -0.33; 95% CI, -0.55 to -0.11). The vegetarian diets had an elevated effect on blood triglycerides (WMD, 0.29; 95% CI, 0.11-0.47). However, there were no significant effects of vegetarian diets on high-density lipoprotein cholesterol (HDLC), Fasting plasma glucose(FPG), and HOMA-IR in these individuals. The results of this study suggest that vegetarian diets effectively reduce LDL-C, TC, and HbA1c levels, thus functioning as a promising therapeutic strategy for improving the metabolic dysfunction in overweight or obese individuals. However, further large-scale clinical trials are required to confirm the validity of these findings.

Do changes in persistent organic pollutants after bariatric surgery cause endocrine disruption?

BACKGROUND

Bariatric surgery results in weight loss, marked endocrine changes and the release of persistent organic pollutants (POPs). The release of POPs might cause endocrine disruption. The study aimed to explore associations between POPs and adiponectin, leptin and ghrelin in subjects undergoing bariatric surgery.

METHODS

The study included 63 subjects with severe obesity (men/women: 13/50), age (years): 45.0 (8.5), and BMI (kg/m²) 39.1 (3.4). Analyses of adiponectin, leptin and ghrelin and POPs (hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (p,p'-DDE), polychlorinated biphenyl (PCB) 118 (dioxin-like compound; dl), and sum 6 PCB (PCB 28, -52, -101, -138, -153, and -180) were performed before and 12 months after bariatric surgery.

RESULTS

There were significant increases in adiponectin and all POPs and a fall in leptin after surgery. The main finding was the highly significant associations between adiponectin and all POPs. The increase in HCB explained 38% of the variation in adiponectin.

CONCLUSIONS

If the POP-associated increase in adiponectin is a causal effect, the release of POPs might have important clinical consequences. Adiponectin has both positive and negative clinical effects exerted by essentially unknown mechanisms. The effects of released POPs on the metabolic functions in subjects undergoing bariatric surgery deserve further evaluation.

Plant-Based Diets and Lipid, Lipoprotein, and Inflammatory Biomarkers of Cardiovascular Disease: A Review of Observational and Interventional Studies

Plant-based diets (PBDs) are becoming increasingly popular. Thus far, the literature has focused on their association with lipid profiles, with less investigation of lipoprotein and inflammatory profiles. Because pro-atherogenic lipid, lipoprotein, and inflammatory processes may facilitate the development of atherosclerosis, understanding the relation between PBDs and these processes is important to inform risk mitigation strategies. Therefore, the objective of this paper was to review the literature on PBDs and lipid, lipoprotein, and inflammatory biomarkers of cardiovascular disease (CVD). A structured literature search was performed, retrieving 752 records, of which 43 articles were included. Plant-based diets generally associated with favourable lipid and lipoprotein profiles, characterised by decreased total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B concentrations, and less low-grade inflammation, characterised by decreased C-reactive protein concentrations. Effect sizes from PBD interventions were greatest compared to habitual dietary patterns, and for non-low-fat vegan and tightly controlled dietary interventions. Associations between PBD indices and the reviewed biomarkers were less consistent. Findings are discussed with reference to the literature on PBDs and PBD indices and CVD risk, the associations between specific plant food groups and CVD outcomes and the reviewed biomarker outcomes, and the potential mechanisms underpinning associations between PBDs and reduced CVD risk.

Plant-Based Diet as a Strategy for Weight Control

According to the World Health Organization, obesity has nearly tripled since the 1970s. Obesity and overweight are major risk factors for cardiovascular diseases, diabetes, inflammatory-mediated diseases, and other serious medical conditions. Moreover, recent data suggest that obesity, overweight, diabetes, and cardiovascular diseases are risk factors for COVID-19-related mortality. Different strategies for weight control have been introduced over the last two decades. Unfortunately, these strategies have shown little effect. At the same time, many studies show that plants might be the key to a successful strategy for weight control. Following the PRISMA guidelines for conducting systematic reviews, a search was conducted in PubMed, Web of Science, Scopus, and Embase using the following keywords: obesity, globesity, vegan, plant-based diet, etc. Our results show that vegan diets are associated with improved gut microbiota symbiosis, increased insulin sensitivity, activation of peroxisome proliferator-activated receptors, and over-expression of mitochondrial uncoupling proteins. The key features of this diet are reduced calorie density and reduced cholesterol intake. The combination of these two factors is the essence of the efficiency of this approach to weight control. Our data suggest that plant-based/vegan diets might play a significant role in future strategies for reducing body weight.

Metabolic adaptations after bariatric surgery: adipokines, myokines and hepatokines

This review addresses the impact of bariatric surgery on the endocrine aspects of white adipose tissue, muscle and the liver. We describe literature supporting the notion that adipokines, myokines and hepatokines likely act in concert and drive many of the long-term metabolic improvements following surgery. Circulating adiponectin is increased while secretion of pro-inflammatory interleukins (1, 6 and 8) decreases, alongside leptin secretion. The metabolic improvements observed in the muscle might relate to reduction of myokines contributing to insulin resistance (including myostatin, brain-derived neurotrophic factor and fibroblast growth factor-21). Subject to exception, hepatokine secretion is generally increased (such as insulin-like growth factor-binding protein 2, adropin and sex hormone-binding globulin). In conclusion, bariatric surgery restores metabolic functions by enhancing the time-dependent secretion of anti-inflammatory, insulin-sensitizing and antilipemic factors. Further research is needed to understand the molecular mechanisms by which these factors may trigger the remission of obesity-related comorbidities following bariatric surgery.

Sex-specific effects of vegetarian diet on adiponectin levels and insulin sensitivity in healthy non-obese individuals

OBJECTIVES

The beneficial influence of a vegetarian diet in reducing the risk for metabolic syndrome has been demonstrated. However, adiponectin production and secretion are scarcely studied in vegetarians, despite their important role in recovering metabolic homeostasis by reducing visceral obesity, inflammation, and insulin resistance. The aim of this study was to evaluate the effect of a vegetarian diet on serum adiponectin levels and its association with the established biomarkers of insulin sensitivity and inflammation in healthy, non-obese individuals.

METHODS

Adiponectin, C-reactive protein, uric acid, glucose, insulin, lymphocyte and polymorphonuclear cell counts were determined in the blood of sex- and age-matched healthy vegetarian (n = 40) and omnivore (n = 36) individuals. The homeostatic model assessment (HOMA-2) calculator was used for the β-cell function (HOMA2-%B) and insulin resistance index (HOMA2-IRI) estimation.

RESULTS

Adiponectin levels were significantly higher in female vegetarians than the respective omnivore controls (P = 0.03), whereas no dietary-associated difference was observed in men. HOMA2-%B was significantly higher in vegetarians than in omnivore controls (P = 0.04), whereas no diet-dependent differences were found in insulin, HOMA2-IRI, inflammatory, and metabolic biomarkers. Multiple regression analysis showed that adiponectin levels were significantly predicted by the type of diet only in women (P = 0.042), whereas no associations were found in men.

CONCLUSIONS

A vegetarian diet resulted in improved β-cell function. Favorable adiponectin and insulin sensitivity responses in women reveal a distinct effect of diet-to-metabolic homeostasis, indicating an interesting pattern of sexual dimorphism regarding the beneficial metabolic effect of a vegetarian diet.

The effects of plant-based diets on the body and the brain: a systematic review

Western societies notice an increasing interest in plant-based eating patterns such as vegetarian and vegan, yet potential effects on the body and brain are a matter of debate. Therefore, we systematically reviewed existing human interventional studies on putative effects of a plant-based diet on the metabolism and cognition, and what is known about the underlying mechanisms. Using the search terms "plant-based OR vegan OR vegetarian AND diet AND intervention" in PubMed filtered for clinical trials in humans retrieved 205 studies out of which 27, plus an additional search extending the selection to another five studies, were eligible for inclusion based on three independent ratings. We found robust evidence for short- to moderate-term beneficial effects of plant-based diets versus conventional diets (duration ≤ 24 months) on weight status, energy metabolism and systemic inflammation in healthy participants, obese and type-2 diabetes patients. Initial experimental studies proposed novel microbiome-related pathways, by which plant-based diets modulate the gut microbiome towards a favorable diversity of bacteria species, yet a functional "bottom up" signaling of plant-based diet-induced microbial changes remains highly speculative. In addition, little is known, based on interventional studies about cognitive effects linked to plant-based diets. Thus, a causal impact of plant-based diets on cognitive functions, mental and neurological health and respective underlying mechanisms has yet to be demonstrated. In sum, the increasing interest for plant-based diets raises the opportunity for developing novel preventive and therapeutic strategies against obesity, eating disorders and related comorbidities. Still, putative effects of plant-based diets on brain health and cognitive functions as well as the underlying mechanisms remain largely unexplored and new studies need to address these questions.

Dietary modifications for weight loss and weight loss maintenance

Worldwide obesity rates remain at a rise, and to treat obesity is at the top of the global public health agenda. In 2013, the AHA/ACC/TOS obesity management guidelines were published, in essence suggesting that any dietary scheme seems to be effective for weight loss, as long as it can induce a sustainable energy deficit. In the present review, we update and critically discuss available information regarding dietary modifications for weight loss and weight loss maintenance, published after the 2013 guidelines. Regarding weight loss, we found no proof to support that a single dietary scheme, be it nutrient-, food group- or dietary pattern- based, is more efficacious of the other for achieving weight loss. For weight loss maintenance, published interventions point towards the same direction, although inconclusively. Most research explores the effect of weight loss regimes on weight loss maintenance and not the effect of the diet during weight loss maintenance, and this literature gap should be more thoroughly investigated.

Gene Expression Analysis to Assess the Relevance of Rodent Models to Human Lung Injury

The relevance of animal models to human diseases is an area of intense scientific debate. The degree to which mouse models of lung injury recapitulate human lung injury has never been assessed. Integrating data from both human and animal expression studies allows for increased statistical power and identification of conserved differential gene expression across organisms and conditions. We sought comprehensive integration of gene expression data in experimental acute lung injury (ALI) in rodents compared with humans. We performed two separate gene expression multicohort analyses to determine differential gene expression in experimental animal and human lung injury. We used correlational and pathway analyses combined with external in vitro gene expression data to identify both potential drivers of underlying inflammation and therapeutic drug candidates. We identified 21 animal lung tissue datasets and three human lung injury bronchoalveolar lavage datasets. We show that the metasignatures of animal and human experimental ALI are significantly correlated despite these widely varying experimental conditions. The gene expression changes among mice and rats across diverse injury models (ozone, ventilator-induced lung injury, LPS) are significantly correlated with human models of lung injury (Pearson r = 0.33-0.45, P < 1E^-16). Neutrophil signatures are enriched in both animal and human lung injury. Predicted therapeutic targets, peptide ligand signatures, and pathway analyses are also all highly overlapping. Gene expression changes are similar in animal and human experimental ALI, and provide several physiologic and therapeutic insights to the disease.

Addition of Exercise Increases Plasma Adiponectin and Release from Adipose Tissue

INTRODUCTION

Adiponectin is an adipose tissue-derived anti-inflammatory protein that is down-regulated in obesity. The effects of caloric restriction and exercise-induced weight loss on adiponectin are not clear.

PURPOSE

To determine whether addition of aerobic exercise training to caloric restriction has additive effects over caloric restriction alone on circulating adiponectin concentrations and adiponectin release from abdominal and gluteal adipose tissue.

METHODS

Overweight or obese (body mass index, 25-40 kg·m(-2); waist >88 cm) postmenopausal women were randomized to 20-wk caloric restriction with and without aerobic exercise (CR + EX, n = 48; and CR, n = 22). Blood samples were collected for measuring plasma adiponectin concentration, and abdominal and gluteal subcutaneous adipose tissue biopsies were performed in a subgroup to determine in vitro adiponectin release, before and after the interventions.

RESULTS

The interventions elicited similar amounts of weight loss (CR + EX, -11.3 ± 4.6 kg; CR,-11.2 ± 3.4 kg) and fat loss (CR + EX, -8.0 ± 3.5 kg; CR, -7.4 ± 2.7 kg). The two groups had differential changes in plasma adiponectin concentrations (for interaction, P = 0.014); CR + EX increased (6.9 ± 3.9 to 8.5 ± 4.9 μg·mL(-1); P = 0.0001), whereas CR did not alter (6.4 ± 4.4 to 6.5 ± 4.5 μg·mL(-1); P = 0.42) plasma adiponectin. Likewise, adiponectin release from abdominal and gluteal subcutaneous adipose tissue increased with CR + EX (P = 0.0076 and P = 0.089, respectively) but did not change with CR (P = 0.13 and P = 0.95, respectively).

CONCLUSION

Despite similar reductions in body weight and fat mass, the addition of aerobic exercise to caloric restriction increased plasma adiponectin concentrations, which may be partly explained by increased adiponectin release from abdominal and gluteal subcutaneous adipose tissue.

METABOLIC EFFECTS OF ADIPONECTINE

The metabolic effects of adiponectine are discussed and its possible role in the development of metabolic syndrome, insulin resistance, diabetes mellitus 2nd type, atherosclerosis; prognostic significance of adiponectine as a marker for ischemic heart disease and future cardiovascular events, therapeutical perspectives of adiponectine use. 

Metabolic surgery: action via hormonal milieu changes, changes in bile acids or gut microbiota? A summary of the literature

Obesity and type 2 diabetes remain epidemic problems. Different bariatric surgical techniques causes weight loss and diabetes remission to varying degrees. The underlying mechanisms of the beneficial effects of bariatric surgery are complex, and include changes in diet and behaviour, as well as changes in hormones, bile acid flow, and gut bacteria. We summarized the effects of multiple different bariatric procedures, and their resulting effects on several hormones (leptin, ghrelin, adiponectin, glucagon-like peptide 1 (GLP-1), peptide YY, and glucagon), bile acid changes in the gut and the serum, and resulting changes to the gut microbiome. As much as possible, we have tried to incorporate multiple studies to try to explain underlying mechanistic changes. What emerges from the data is a picture of clear differences between restrictive and metabolic procedures. The latter, in particular the roux-en-Y gastric bypass, induces large and distinctive changes in most measured fat and gut hormones, including early and sustained increase in GLP-1, possible through intestinal bile acid signalling. The changes in bile flow and the gut microbiome are causally inseparable so far, but new studies show that each contributes to the effects of weight loss and diabetes resolution.

Green tea extract improves high fat diet-induced hypothalamic inflammation, without affecting the serotoninergic system

To investigate possible mechanisms of green tea's anti-obesity and anti-diabetic effects in the hypothalamus, the central regulator of metabolism, of mice fed with high-fat diet (HFD), we analyzed proteins of the toll-like receptor 4 (TLR4) pathway and serotoninergic proteins involved in energy homeostasis. Thirty-day-old male Swiss mice were fed with HFD rich in saturated fat and green tea extract (GTE) for 8 weeks. After that, body weight and mass of fat depots were evaluated. Oral glucose tolerance test was performed 3 days prior to euthanasia; serum glucose, insulin and adiponectin were measured in fasted mice. Hypothalamic TLR4 pathway proteins, serotonin receptors 1B and 2C and serotonin transporter were analyzed by Western blotting or enzyme-linked immunosorbent assay. A second set of animals was used to measure food intake in response to fluoxetine, a selective serotonin reuptake inhibitor. Mice fed with HFD had increased body weight and mass of fat depots, impaired oral glucose tolerance, elevated glucose and insulin and decreased adiponectin serum levels. TLR4, IκB-α, nuclear factor κB p50 and interleukin 6 were increased by HFD. Concomitant GTE treatment ameliorated these parameters. The serotoninergic system remained functional after HFD treatment despite a few alterations in protein content of serotonin receptors 1B and 2C and serotonin transporter. In summary, the GTE attenuated the deleterious effects of the HFD investigated in this study, partially due to reduced hypothalamic inflammation.