Postprandial leptin and adiponectin in response to sugar and fat in obese and normal weight individuals

Morin inhibits the activity of pancreatic lipase and adipogenesis

Obesity is a major health issue that contributes significantly to increased mortality and morbidity worldwide. Obesity is caused by uncontrolled adipogenesis and lipogenesis, leading to several metabolism-associated problems. Pancreatic lipase, an enzyme that breaks down dietary lipids, is a prominent target for obesity. Orlistat, a known inhibitor of pancreatic lipase, is commonly employed for the management of obesity. However, its side effects, such as diarrhoea, nausea and bladder pain, urge to look out for safer alternatives. Morin is a pentahydroxyflavone, exerts a broad spectrum of pharmacological effects including antioxidant, anti-inflammatory, lipid lowering, anti-diabetic, anti-fibrotic, anti-cancer, etc. This study investigated the effect of morin on pancreatic lipase activity, in vitro and in vivo adipogenesis. Molecular docking and simulation studies showed morin to have a higher binding affinity towards pancreatic lipase compared with orlistat, which also inhibited its activity in vitro. Morin also reduced lipid droplet accretion and downregulated the expression of adipogenic and lipogenic genes. The acute oral toxicity of morin was determined in C57BL/6 mice, where morin did not show toxicity up to 2000 mg/kg body weight dose. Oral administration of morin to high fat diet fed mice reduced body weight, glucose and insulin levels. Also, the histopathological examination revealed reduction in adipocyte size and decreased mRNA expression of adipogenesis markers in white adipose tissue of morin administered group compared to high fat diet group. Overall, the results suggested morin inhibited pancreatic lipase activity, adipogenesis and further studies are warranted to explore its therapeutic potential for obesity.

Adipokine receptor expression in mast cells is altered by specific ligands and proinflammatory cytokines

Adipokines play essential roles in regulating a range of biological processes, but growing evidence indicates that they are also fundamental in immunological mechanisms and, primarily, inflammatory responses. Adipokines mediate their actions through specific receptors. However, although adipokine receptors are widely distributed in many cell and tissue types, limited data are available on their expression in mast cells (MCs) and, consequently, adipokine's significance in the modulation of MC activity within the tissues. In this study, we demonstrate that rat peritoneal MCs constitutively express the leptin receptor (i.e. LEPR), adiponectin receptors (i.e. ADIPOR1 and ADIPOR2) and the chemerin receptor (i.e. CMKLR1). We also found that LEPR, ADIPOR1, ADIPOR2 and CMKLR1 expression in MCs changes in response to stimulation by their specific ligands and some cytokines with potent proinflammatory properties. Furthermore, the involvement of intracellular signaling molecules in leptin-, adiponectin- and chemerin-induced MC response was analyzed. Overall, our findings suggest that adipokines leptin, adiponectin and chemerin can significantly affect the activity of MCs in various processes, especially during inflammation. These observations may contribute significantly to understanding the relationship between adipokines, immune mechanisms and diseases or conditions with an inflammatory component.

Interplay of Postprandial Triglyceride-Rich Lipoprotein Composition and Adipokines in Obese Adolescents

In the context of the alarming rise of infant obesity and its health implications, the present research aims to uncover disruptions in postprandial lipid metabolism and the composition of triglyceride-rich lipoproteins in obese adolescents. A double-blind, controlled clinical trial in the postprandial phase on 23 adolescents aged 12 to 16 years was carried out. Twelve participants were categorized as obese (BMI > 30 kg/m2 and percentile > 95) and 11 as normal-weight (BMI = 20-25 kg/m2, percentile 5-85). Blood samples were collected after a 12-h overnight fast and postprandially after consumption of a standardized breakfast containing olive oil, tomato, bread, orange juice, and skimmed milk. Obese adolescents exhibited elevated triglyceride concentrations in both fasting and postprandial states and higher TG/apo-B48 ratios, indicating larger postprandial triglyceride-rich lipoprotein (TRL) particle size, which suggests impaired clearance. Obese subjects also exhibited higher n-6 PUFA concentrations, potentially linked to increased TRL hydrolysis and the release of pro-inflammatory adipokines. In contrast, TRL from normal-weight individuals showed higher concentrations of oleic acid and DHA (n-3 PUFA), with possible anti-inflammatory effects. The results indicate an interplay involving postprandial TRL metabolism and adipokines within the context of adolescent obesity, pointing to potential cardiovascular implications in the future.

Distinct adaptations of endocrine and cognitive functions may contribute to high variability in long-term weight loss outcome after bariatric surgery

BACKGROUND

Bariatric surgery has been widely recognized as the most efficient long-term treatment method in severe obesity, yet therapy success shows considerable interindividual variability. Postoperative metabolic adaptations, including improved gut hormone secretion (GLP-1, PYY and ghrelin), and restored executive function may play an explanatory role in weight loss, yet causes for poor success in individual patients remain unknown. This study investigates gut-hormonal and cognitive characteristics in extreme weight loss responders to bariatric surgery.

METHODS

Patients (n=47) with high or low excessive weight loss (EWL) at least 2 years after Roux-en-Y-gastric bypass or sleeve gastrectomy were allocated into good responders (GR, EWL 82.4 ± 11.6%) and poor responders (PR, EWL 24.0 ± SD 12.8%) to study differences in postprandial secretion of GLP-1, PYY, ghrelin and in working memory (WM).

RESULTS

Mean BMI was 47.1 ± 6.2 kg/m² in PR (n=21) and 28.9 ± 3.1 kg/m² in GR (n=26, p < 0.001). Fasted GLP-1 and PYY were comparable for GR and PR (p > 0.2) and increased strongly after a standardized test meal (300 kcal liquid meal) with a peak at 15 to 30 minutes. The increase was stronger in GR compared to PR (GLP-1, PYY: Time x Group p < 0.05). Plasma ghrelin levels already differed between groups at fasted state, showing significantly higher levels for GR (p < 0.05). Postprandially, ghrelin secretion was suppressed in both groups, but suppression was higher in GR (Time x Group p < 0.05). GR showed significantly higher WM scores than PR (p < 0.05). Postprandial ghrelin (iAUC), but not GLP-1 or PYY plasma levels, significantly mediated the relationship between EWL and a WM subscore (IS score, CI = 0.07 - 1.68), but not WM main score (MIS score, CI = -0.07 - 1.54), in mediation analyses.

CONCLUSION

Excess weight loss success after bariatric surgical procedures is associated with distinct profiles of gut-hormones at fasted and postprandial state, and differences in working memory. Better working memory performance in GR might be mediated by higher postprandial reduction in ghrelin plasma levels. Future studies need to integrate longitudinal data, larger samples and more sensitive cognitive tests.

Comparison of Adiponectin Levels in Anorexia Nervosa, Bulimia Nervosa, Binge-Eating Disorder, Obesity, Constitutional Thinness, and Healthy Controls: A Network Meta-Analysis

Adiponectin is a protein hormone that is produced and secreted primarily by adipose tissue. The levels of adiponectin in those with eating disorders, obesity, and healthy controls have been extensively studied. However, the general picture of the differences in adiponectin levels across the mentioned conditions is still unclear and fragmented. In this study, we pooled previous studies and performed a network meta-analysis to gain a global picture of comparisons of adiponectin levels across eating disorders, obesity, constitutional thinness, and healthy controls. Electronic databases were searched for anorexia nervosa, avoidant restrictive food intake disorder, binge-eating disorder, bulimia nervosa, healthy controls, night eating syndrome, obesity, and constitutional thinness in studies where adiponectin levels were measured. A total of 4262 participants from 50 published studies were included in the network meta-analysis. Adiponectin levels were significantly higher in participants with anorexia nervosa than in healthy controls (Hedges' g = 0.701, p < 0.001). However, adiponectin levels in constitutionally thin participants were not significantly different from those of healthy controls (Hedges' g = 0.470, p = 0.187). Obesity and binge-eating disorder were associated with significantly lower adiponectin levels compared to those of healthy controls (Hedges' g = -0.852, p < 0.001 and Hedges' g = -0.756, p = 0.024, respectively). The disorders characterized by excessive increases or decreases in BMI were associated with significant changes in adiponectin levels. These results suggest that adiponectin may be an important marker of severely disequilibrated homeostasis, especially in fat, glucose, and bone metabolisms. Nonetheless, an increase in adiponectin may not simply be associated with a decrease in BMI, as constitutional thinness is not associated with a significant increase in adiponectin.

Dietary intervention with 2 different fat profiles; role of the rs822393 variant in metabolic parameter changes

Introduction

Introduction: rs822393 is related to dietary intervention responses. The aim of our study was to analyze the metabolic effects of 2 hypocaloric diets with a different fat profile during 3 months according to the genetic variant rs822393. Methods: a population of 361 obese patients were randomly allocated to one of two diets; Diet P (enriched in polyunsaturated fatty acids) vs. Diet M (enriched in monounsaturated fatty acids). Adiposity and biochemical parameters were determined. rs822393 was assessed by real-time PCR, with a dominant model analysis (CC vs CT+TT). Results: genotype distribution was: 221 CC (61.2 %), 115 CT (31.9 %) and 25 TT (6.9 %). Basal and post-intervention HDL cholesterol, adiponectin levels and adiponectin/leptin ratio were lower in T-allele than non-T-allele carriers. After both diets, BMI, weight, fat mass, waist circumference, systolic blood pressure, insulin levels, HOMA-IR, leptin, total cholesterol and LDL-cholesterol improved significantly in both genotype groups. After Diet P, HDL-cholesterol (delta: 5.6 ± 1.1 mg/dl vs. 2.7 ± 0.9 mg/dl; p = 0.01), serum adiponectin (20.1 ± 2.9 ng/dl vs. 6.8 ± 3.0 ng/dl; p = 0.02) and adiponectin/leptin ratio (0.57 ± 0.1 units vs. 0.20 ± 0.08 units; p = 0.03) improved in non-T allele carriers. The same improvements were observed after Diet M: HDL-cholesterol (delta: 5.5 ± 0.8 mg/dl vs. 3.1 ± 0.9 mg/dl; p = 0.03), serum adiponectin (19.5 ± 2.9 ng/dl vs. 4.5 ± 2.8 ng/dl; p = 0.01), and adiponectin/leptin ratio (0.54 ± 0.1 units vs. 0.15 ± 0.08 units; p = 0.03). These parameters remained unchanged in T-allele carriers. Conclusion: after two different hypocaloric diets, obese subjects with the T allele of rs822393 did not improve their adiponectin levels, ratio adiponectin/leptin, and HDL-cholesterol, despite loss of weight.

Circulating uridine dynamically and adaptively regulates food intake in humans

Feeding behavior must be continuously adjusted to match energy needs. Recent discoveries in murine models identified uridine as a regulator of energy balance. Here, we explore its contribution to the complex control of food intake in humans by administering a single dose of uridine monophosphate (UMP; 0.5 or 1 g) to healthy participants in two placebo-controlled studies designed to assess food behavior (registration: DRKS00014874). We establish that endogenous circulating uridine correlates with hunger and ensuing food consumption. It also dynamically decreases upon caloric ingestion, prompting its potential role in a negative feedback loop regulating energy intake. We further demonstrate that oral UMP administration temporarily increases circulating uridine and-when within the physiological range-enhances hunger and caloric intake proportionally to participants' basal energy needs. Overall, uridine appears as a potential target to tackle dysfunctions of feeding behavior in humans.

Effects of a high-fat meal on inflammatory and endothelial injury biomarkers in accordance with adiposity status: a cross-sectional study

Background

It is known that consuming a high-fat meal (HFM) induces microvascular dysfunction (MD) in eutrophic women and aggravates it in those with obesity. Our purpose was to investigate if the MD observed after a single HFM intake is caused by endothelial damage or increased inflammatory state, both determined by blood biomarkers.

Methods

Nineteen women with obesity (BMI 30-34.9 kg/m²) and 18 eutrophic ones (BMI 20.0-24.9 kg/m²) were enrolled into two groups: Obese (OBG) and Control (CG), respectively. Blood samples were collected at five-time points: before (fasting state) and 30, 60, 120, and 180 min after HFM intake to determine levels of adipokines (adiponectin, leptin), non-esterified fatty acid (NEFA), inflammatory [tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6)] and endothelium damage [soluble E-selectin, soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), plasminogen activator inhibitor-1 (PAI-1)] biomarkers.

Results

Levels of soluble E-selectin, leptin, and PAI-1 were higher in OBG at all-time points (P < 0.05) compared to CG. In the fasting state, OBG had higher levels of NEFA compared to CG (P < 0.05). In intra-group analysis, no significant change in the levels of circulating inflammatory and endothelial injury biomarkers was observed after HFM intake, independently of the group.

Conclusion

Our findings suggest that women with obesity have an increased pro-inflammatory state and more significant endothelial injury compared to eutrophic ones. However, the consumption of a HFM was not sufficient to change circulating levels of inflammatory and endothelial injury biomarkers in either group.

Registration number for clinical trials:

NCT01692327.

Childhood immuno-metabolic markers and risk of depression and psychosis in adulthood: A prospective birth cohort study

BACKGROUND

Metabolic and inflammatory disorders commonly co-occur with depression and psychosis, with emerging evidence implicating immuno-metabolic dysfunction in their aetiology. Previous studies have reported metabolic dysfunction and inflammation in adults with depression and psychosis. However, longitudinal studies testing the direction of association, and the effects of different dimensions of early-life immuno-metabolic dysfunction on adult psychopathology are limited.

METHODS

Using data from 3258 birth cohort participants we examined longitudinal associations of three metabolic hormones (leptin, adiponectin, insulin) at age 9 with risks for depression- and psychosis-spectrum outcomes at age 24. In addition, using nine immuno-metabolic biomarkers (leptin, adiponectin, insulin, interleukin-6, C-Reactive protein, low density lipoprotein, high density lipoprotein, triglycerides, and BMI), we constructed an exploratory bifactor model showing a general immuno-metabolic factor and three specific factors (adiposity, inflammation, and insulin resistance), which were also used as exposures.

RESULTS

Childhood leptin was associated with adult depressive episode (adjusted odds ratio (aOR)= 1.31; 95% CI, 1.02-1.71) and negative symptoms (aOR=1.15; 95% CI, 1.07-1.24), but not positive psychotic symptoms. The general immuno-metabolic factor was associated with atypical depressive symptoms (aOR=1.07; 95% CI, 1.01-1.14) and psychotic experiences (aOR=1.21; 95% CI, 1.02-1.44). The adiposity factor was associated with negative symptoms (aOR=1.07; 95% CI 1.02-1.12). Point estimates tended to be larger in women, though 95% credible intervals overlapped with those for men. In women, the inflammatory factor was associated with depressive episodes (aOR=1.27; 95% CI, 1.03-1.57).

CONCLUSIONS

While general immuno-metabolic dysfunction in childhood may contribute to risks for both psychotic and depressive symptoms in adulthood, childhood adiposity and inflammation appear to be particularly linked to affective (depressive and negative), but not positive psychotic symptoms.

A nexus of lipid and O-Glcnac metabolism in physiology and disease

Although traditionally considered a glucose metabolism-associated modification, the O-linked β-N-Acetylglucosamine (O-GlcNAc) regulatory system interacts extensively with lipids and is required to maintain lipid homeostasis. The enzymes of O-GlcNAc cycling have molecular properties consistent with those expected of broad-spectrum environmental sensors. By direct protein-protein interactions and catalytic modification, O-GlcNAc cycling enzymes may provide both acute and long-term adaptation to stress and other environmental stimuli such as nutrient availability. Depending on the cell type, hyperlipidemia potentiates or depresses O-GlcNAc levels, sometimes biphasically, through a diversity of unique mechanisms that target UDP-GlcNAc synthesis and the availability, activity and substrate selectivity of the glycosylation enzymes, O-GlcNAc Transferase (OGT) and O-GlcNAcase (OGA). At the same time, OGT activity in multiple tissues has been implicated in the homeostatic regulation of systemic lipid uptake, storage and release. Hyperlipidemic patterns of O-GlcNAcylation in these cells are consistent with both transient physiological adaptation and feedback uninhibited obesogenic and metabolic dysregulation. In this review, we summarize the numerous interconnections between lipid and O-GlcNAc metabolism. These links provide insights into how the O-GlcNAc regulatory system may contribute to lipid-associated diseases including obesity and metabolic syndrome.

Altered Adiponectin Response in Older Women Following Dextrose and High-Fat Dietary Challenges

SCOPE

Despite its beneficial properties, higher adiponectin concentrations are paradoxically associated with mortality in advanced age. Several mechanisms are being discussed. However, little is known about postprandial regulation of adiponectin in older adults. We assessed age-specific differences of the adiponectin response to different test meals considering potential determinants.

METHODS AND RESULTS

Older (n = 20) and younger (n = 22) women are randomized to a dextrose (DEX) or high-fat (HF) dietary challenge. Postprandial adiponectin and fibroblast growth factor 21 (FGF21) concentrations are measured before and 60, 120, 240 min after ingestion. We assessed postprandial changes and group differences using linear mixed models controlled for possible determinants. In younger women, postprandial adiponectin remains stable after both test meals. In contrast, adiponectin increases following DEX and decreases after HF in older women, irrespective of control variables. Postprandial adiponectin is positively associated with malondialdehyde and inversely associated with interleukin-6 following DEX and also negatively associated with metabolic parameters after both test meals. In older women, elevated postprandial FGF21 concentrations are associated with a higher adiponectin response (β = 30.7, 95% CI 10.6-50.8, p = 0.007).

CONCLUSIONS

Adiponectin response is associated with type of dietary challenge, age, and FGF21 response. Age-group differences are partly attributable to metabolic parameters and oxidative stress.

Dietary influence on adiponectin in patients with type 2 diabetes

BACKGROUND

Here, we evaluate the effects of a diet rich in low-glycaemic index carbohydrates and fibre (CHO/Fibre diet) or monounsaturated fatty acids (MUFA diet), on fasting and postprandial adiponectin concentrations and their relationship with the beneficial effects of the experimental diets on postprandial glucose metabolism and liver fat in type 2 diabetes (T2D).

METHODS

Fasting and postprandial adiponectin plasma concentrations were measured before and after dietary interventions in the participants to a randomized controlled trial (NCT01025856), wherein 37 men and 8 women with T2D, aged 35-70 years, followed a CHO/Fibre diet or a MUFA diet for an 8-week period. Hepatic fat content by ¹ H NMR and fasting and postprandial plasma glucose and insulin measurements were also available.

RESULTS

Fasting adiponectin plasma levels did not change after both diets. Postprandial adiponectin significantly increased after the CHO/fibre diet (9.9 ± 1.6 μg/mL vs. 10.8 ± 2.3 μg/mL; P = .033) but not after the MUFA diet (10.6 ± 1.8 μg/mL vs. 10.6 ± 1.6 μg/mL; P = .935) with a significant difference between changes (P = .035). In the combined CHO/Fibre and MUFA groups, fasting and postprandial adiponectin significantly and inversely correlated with postprandial insulin iAUC at baseline and after intervention, and with liver fat content after intervention.

CONCLUSIONS

A diet rich in CHO/Fibre increased postprandial plasma adiponectin significantly more than a MUFA diet in patients with T2D. Independently of diet, adiponectin levels associated with postprandial insulin concentrations. The dietary interventions modulated the relationship between adiponectin and liver fat.

Adiponectin, Leptin and Cardiovascular Disorders

The landmark discoveries of leptin and adiponectin firmly established adipose tissue as a sophisticated and highly active endocrine organ, opening a new era of investigating adipose-mediated tissue crosstalk. Both obesity-associated hyperleptinemia and hypoadiponectinemia are important biomarkers to predict cardiovascular outcomes, suggesting a crucial role for adiponectin and leptin in obesity-associated cardiovascular disorders. Normal physiological levels of adiponectin and leptin are indeed essential to maintain proper cardiovascular function. Insufficient adiponectin and leptin signaling results in cardiovascular dysfunction. However, a paradox of high levels of both leptin and adiponectin is emerging in the pathogenesis of cardiovascular disorders. Here, we (1) summarize the recent progress in the field of adiponectin and leptin and its association with cardiovascular disorders, (2) further discuss the underlying mechanisms for this new paradox of leptin and adiponectin action, and (3) explore the possible application of partial leptin reduction, in addition to increasing the adiponectin/leptin ratio as a means to prevent or reverse cardiovascular disorders.