Obesity, metabolic syndrome and bariatric surgery: A narrative review

A Novel Polysaccharide From Tremella fuciformis Alleviated High-Fat Diet-Induced Obesity by Promoting AMPK/PINK1/PRKN-Mediated Mitophagy in Mice

SCOPE

Polysaccharides from Tremella fuciformis have gained significant interest due to their diverse biological activities. This study focuses on characterizing a purified polysaccharide, TPSP2, extracted from T. fuciformis and evaluating its antiobesity effect and underlying mechanisms in vivo.

METHODS AND RESULTS

Structural analysis revealed that TPSP2, with a molecular weight of 1.51 × 103 kDa, is composed of mannose, rhamnose, glucuronic acid, galactose, xylose, arabinose, and fucose in specific molar ratios. The primary linkages identified include t-Fuc(p), 1,2-Xyl(p), t-GlcA(p), 1,3-Man(p), and 1,2,3-Man(p), with their corresponding ratios being 12.987%, 11.404%, 16.050%, 16.527%, and 26.624%, respectively. In vivo experiments demonstrated that TPSP2 significantly alleviated high-fat diet-induced weight gain, hyperlipidemia, hepatic steatosis, hyperglycemia, and insulin resistance in mice. Mechanistically, TPSP2 was found to enhance AMPK/PINK1-PRKN-dependent mitophagy by upregulating the p-AMPK/AMPK ratio, LC3-II/I ratio, and expression of PINK1, PRKN, prohibitin 2 (PHB2), and LAMP2, while downregulating p62 and TOM20 expression.

CONCLUSION

This study suggested that TPSP2 could be a promising candidate for addressing obesity-related metabolic disorders by targeting mitochondrial quality control mechanisms.

The Role of Adipocyte Endoplasmic Reticulum Stress in Obese Adipose Tissue Dysfunction: A Review

Adipose tissue dysfunction plays an important role in metabolic diseases associated with chronic inflammation, insulin resistance and lipid ectopic deposition in obese patients. In recent years, it has been found that under the stimulation of adipocyte endoplasmic reticulum stress (ERS), the over-activated ER unfolded protein response (UPR) exacerbates the inflammatory response of adipose tissue by interfering with the normal metabolism of adipose tissue, promotes the secretion of adipokines, and affects the browning and thermogenic pathways of adipose tissue, ultimately leading to the manifestation of metabolic syndrome such as ectopic lipid deposition and disorders of glucolipid metabolism in obese patients. This paper mainly summarizes the relationship between adipocyte ERS and obese adipose tissue dysfunction and provides an overview of the mechanisms by which ERS induces metabolic disorders such as catabolism, thermogenesis and inflammation in obese adipose tissue through the regulation of molecules and pathways such as NF-κB, ADPN, STAMP2, LPIN1, TRIP-Br2, NF-Y and SIRT2 and briefly describes the current mechanisms targeting adipocyte endoplasmic reticulum stress to improve obesity and provide ideas for intervention and treatment of obese adipose tissue dysfunction.

Body mass index and risk of mortality in patients undergoing bariatric surgery

BACKGROUND

Prior literature has demonstrated that bariatric surgery is a safe approach for patients with morbid obesity. However, the relationship between body mass index (BMI) and risk of mortality in these patients has not been fully elucidated. Primary objective of this study was to evaluate the relationship between BMI and risk of mortality using data obtained from a national database, with a special focus on patients with BMI ≥ 70.0 kg/m².

METHODS

A retrospective cohort study of patients with morbid obesity (BMI ≥ 40 kg/m²) undergoing first-time bariatric surgery between 2015 and 2018 was performed using data from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program. Primary outcome was intra-operative death or death within 30 days post-operatively. Patients were categorized into quartiles according to BMI. Multivariable analysis was performed to evaluate the association of BMI with risk of mortality. Relative risk (RR) and 95% confidence interval (CI) are provided as measures of strength of association and precision, respectively.

RESULTS

A total of 463, 436 patients were included with a 30-day mortality rate of 0.11%. Mean BMI (SD) was 48.2 (7.3) kg/m²; 1.5% of patients had BMI ≥ 70.0 kg/m². On multivariable analysis, highest quartile patients had a significantly higher risk of mortality than lowest quartile patients. For patients with BMI ≥ 70.0 kg/m², the risk of mortality was more pronounced with an eightfold increase compared to the lowest quartile. In patients with BMI ≥ 70.0 kg/m², although sleeve gastrectomy (SG) was the most common procedure, the risk of mortality was significantly higher in patients undergoing Roux-en-Y gastric bypass (RYGB).

CONCLUSIONS

BMI is associated with increased risk of 30-day mortality. The effect of BMI is more pronounced in patients with BMI ≥ 70.0 kg/m². In these patients, RYGB is associated with increased risk of mortality compared to SG.

Can Leptin/Ghrelin Ratio and Retinol-Binding Protein 4 Predict Improved Insulin Resistance in Patients with Obesity Undergoing Sleeve Gastrectomy?

Introduction

Obesity is associated with metabolic syndrome (MBS), a cluster of components including central obesity, insulin resistance (IR), dyslipidemia, and hypertension. IR is the major risk factor in the development and progression of type 2 diabetes mellitus in obesity and MBS. Predicting preoperatively whether a patient with obesity would have improved or non-improved IR after bariatric surgery would improve treatment decisions.

Methods

A prospective cohort study was conducted between August 2019 and September 2021. We identified pre- and postoperative metabolic biomarkers in patients who underwent laparoscopic sleeve gastrectomy. Patients were divided into two groups: group A (IR < 2.5), with improved IR, and group B (IR ≥ 2.5), with non-improved IR. A prediction model and receiver operating characteristics (ROC) were used to determine the effect of metabolic biomarkers on IR.

Results

Seventy patients with obesity and MBS were enrolled. At 12-month postoperative a significant improvement in lipid profile, fasting blood glucose, and hormonal biomarkers and a significant reduction in the BMI in all patients (p = 0.008) were visible. HOMA-IR significantly decreased in 57.14% of the patients postoperatively. Significant effects on the change in HOMA-IR ≥ 2.5 were the variables; preoperative BMI, leptin, ghrelin, leptin/ghrelin ratio (LGr), insulin, and triglyceride with an OR of 1.6,1.82, 1.33, 1.69, 1.77, and 1.82, respectively (p = 0.009 towards p = 0.041). Leptin had the best predictive cutoff value on ROC (86% sensitivity and 92% specificity), whereas ghrelin had the lowest (70% sensitivity and 73% specificity).

Conclusion

Preoperative BMI, leptin, ghrelin, LGr, and increased triglycerides have a predictive value on higher postoperative, non-improved patients with HOMA-IR (≥ 2.5). Therefore, assessing metabolic biomarkers can help decide on treatment/extra therapy and outcome before surgery.

Graphical Abstract

The Main Anthocyanin Monomer from Lycium ruthenicum Murray Fruit Mediates Obesity via Modulating the Gut Microbiota and Improving the Intestinal Barrier

Anthocyanins have been shown to exert certain antiobesity properties, but the specific relationship between anthocyanin-induced beneficial effects and the gut microbiota remains unclear. Petunidin-3-O-[rhamnopyranosyl-(trans-p-coumaroyl)]-5-O-(β-D-glucopyranoside) (P3G) is the main anthocyanin monomer from the fruit of Lycium ruthenicum Murray. Therefore, in this study, we investigated the antiobesity and remodeling effects of P3G on gut microbiota through a high-fat diet (HFD)-induced obesity mouse model and a fecal microbiota transplantation experiment. P3G was found to reduce body weight gain, fat accumulation, and liver steatosis in HFD-induced obese mice. Moreover, supplementation with P3G alleviated the HFD-induced imbalance in gut microbiota composition, and transferring the P3G-regulated gut microbiota to recipient mice provided comparable protection against obesity. This is the first time evidence is provided that P3G has an antiobesity effect by changing the intestinal microbiota. Our present data highlight a link between P3G intervention and enhancement in gut barrier integrity. This may be a promising option for obesity prevention.

Black rice anthocyanins alleviate hyperlipidemia, liver steatosis and insulin resistance by regulating lipid metabolism and gut microbiota in obese mice

Hyperlipidemia, liver steatosis and insulin resistance are common metabolic diseases associated with obesity. The present study was designed to investigate the in vivo protective value of black rice anthocyanins (BRAN) on hyperlipidemia, liver steatosis and insulin resistance in mice with high-fat-diet (HFD)-induced obesity and elucidate the underlying mechanism. Specific pathogen-free male C57BL/6J mice (four weeks old, weighing 17.6-20.9 g) were randomly divided into three groups and fed with low-fat diet (LFD, 10% fat energy), HFD (45% fat energy), or HFD supplemented with BRAN by intragastric administration for 14 weeks. The obesity-related biochemical indices and hepatic gene expression levels were determined. 16S rRNA sequencing was used to determine the gut microbial changes induced by BRAN treatment. The results showed that the body weight gain, triglycerides, total cholesterol, steatosis scores and insulin resistance index in the BRAN group decreased by 24.69%, 29.83%, 28.08%, 46.67% and 40.42%, respectively, compared to the HFD group. Gene expression analysis indicated that BRAN treatment improved the gene expression profiles involved in lipid metabolism compared with the mice fed HFD alone. Moreover, BRAN treatment significantly altered the composition of the gut microbiota, which was closely correlated with the obesity-related biomarkers. In conclusion, this study demonstrated that dietary supplementation of BRAN protected from obesity-associated hyperlipidemia, hepatic steatosis and insulin resistance by influencing the gut microbiota and lipid metabolism.

Pharmacological and structure-activity relationship studies of oleoyl-lysophosphatidylinositol synthetic mimetics

Metabolic diseases, such as obesity and type 2 diabetes, are relentlessly spreading worldwide. The beginning of the 21st century has seen the introduction of mechanistically novel types of drugs, aimed primarily at keeping these pathologies under control. In particular, an important family of therapeutics exploits the beneficial physiology of the gut-derived glucagon-like peptide-1 (GLP-1), with important clinical benefits, from glycaemic control to cardioprotection. Nonetheless, these protein-based drugs act systemically as exogenous GLP-1 mimetics and are not exempt from side effects. The food-derived lipid oleoyl-lysophosphatidylinositol (LPI) is a potent GPR119-dependent GLP-1 secreting agent. Here we present a structure-activity relationship (SAR) study of a synthetic library of oleoyl-LPI mimetics capable to induce the physiological release of GLP-1 from gastrointestinal enteroendocrine cells (EECs). The best lead compounds have shown potent and efficient release of GLP-1 in vitro from human and murine cells, and in vivo in diabetic db/db mice. We have also generated a molecular model of oleoyl-LPI, as well as its best performing analogues, interacting with the orthosteric site of GPR119, laying foundational evidence for their pharmacological activity.

Type 2 diabetes mellitus status in obese patients following sleeve gastrectomy or one anastomosis gastric bypass

This study aims to compare sleeve gastrectomy (SG) and one anastomosis gastric bypass (OAGB) in terms of remission of type 2 diabetes mellitus (T2DM) in obese patients. All T2DM patients were followed-up for at least 36 months. The primary outcome was remission of T2DM. Secondary endpoints included weight reduction and the procedure’s impact on quality of life. In total, 53/1177 morbidly obese patients who underwent SG (Group A, n = 28) or OAGB (Group B, n = 25) had T2DM. Preoperatively, the mean Body Mass Index (BMI) values were 52.2 ± 8.5 kg/m² and 52.9 ± 10.9 kg/m² for Group A and Group B, respectively. Six patients in Group A were insulin dependent, while 8 were insulin dependent in Group B. After 36 months, diabetes remission was achieved by only 10 patients (35.7%) in Group A. However, in Group B, 22 patients (88%) remained off antidiabetic agents (p < 0.0001), with ΔHbA1c (%) reaching 1.4 ± 1.5% in Group A and 2.7 ± 2.1% in Group B (p = 0.02). Excess weight loss% (%EWL) was again significantly different between the two groups (MA = 79.8 ± 14.5%, MB = 93.3 ± 16.0%, p = 0.003). OAGB is more effective in improving glycaemic control and %EWL, with almost immediate resolution of diabetes, as well as long-term weight loss.

The Incidence and Risk Factors of Cholelithiasis Development After Bariatric Surgery in Saudi Arabia: A Two-Center Retrospective Cohort Study

Background: Rapid weight loss after bariatric surgery is a known risk factor for cholelithiasis development. This study aimed to estimate the incidence of cholelithiasis following bariatric surgery among morbidly obese patients who underwent bariatric surgery. Methods: This is a retrospective cohort study of all morbidly obese patients who underwent bariatric surgery in King Abdulaziz Medical City (Riyadh, Saudi Arabia) or King Abdulaziz Hospital (Al Ahsa, Saudi Arabia) between January 2015 and December 2018. Patients with a history of cholecystectomy or previous bariatric surgery were excluded. We estimated the incidence rate of cholelithiasis among the cohort. We also examined the associated risk factors of cholelithiasis development. Results: The study cohort contained 490 patients (38.7% males; 61.43% females) with a mean age of 36.87 ± 11.44 years. Most patients (58.54%) were followed up for 12 months. The incidence of cholelithiasis post-operation was 6.53% (n = 32). The average period of cholelithiasis formation was 12-24 months. The percentage of total weight loss (TWL%) was significantly associated with the development of cholelithiasis post-operatively. Conclusion: A significant association was found between weight loss following bariatric surgery and the incidence of cholelithiasis. Gender, age, and comorbidities were not associated with the formation of cholelithiasis. We recommend regular follow-up appointments with thorough patient education about gradual weight loss to reduce the risk of developing cholelithiasis.