Dipeptidyl peptidase-4 activity, lipopolysaccharide, C-reactive protein, glucose metabolism, and gut peptides 3 months after bariatric surgery

Liraglutide prevents body and fat mass gain in ovariectomized Wistar rats

Estrogens exert beneficial metabolic effects by reducing food intake and enhancing energy expenditure through both central and peripheral mechanisms. The decrease of estrogen, as occurs in ovariectomy (OVX), leads to metabolic disturbances, such as increased body weight, adipose tissue mass, basal blood glucose, and impaired glucose tolerance. These effects can be reversed by reintroducing estrogen. GLP-1 and its receptor agonists, known for their antihyperglycemic properties, also exhibit anorexigenic effects. Besides that, research indicates that GLP-1 analogs can induce metabolic changes peripherally, such as increased fatty acid oxidation and inhibited lipogenesis. Given the shared metabolic actions of GLP-1 and estrogens, we explored whether liraglutide, a GLP-1 agonist, could mitigate the metabolic effects of estrogen deficiency. We tested this hypothesis using ovariectomized rats, a model that simulates menopausal estrogen deficiency, and treated them with either liraglutide or 17β-Estradiol benzoate for 21 days. Ovariectomy resulted in elevated DPP-IV activity in both plasma and inguinal white adipose tissue (iWAT). While estrogen replacement effectively countered the DPP-IV increase in both plasma and iWAT, liraglutide only prevented the rise in iWAT DPP-IV activity. Liraglutide prevented body weight and fat mass gain after ovariectomy to the same extent as estradiol treatment. This can be explained by the lower food intake and food efficiency caused by estradiol and liraglutide. However, liraglutide was associated with increased pro-inflammatory cytokines and inflammatory cells in white adipose tissue. Further research is crucial to fully understand the potential benefits and risks of using GLP-1 receptor agonists in the context of menopause.

DPP-IV as a potential candidate in anti-obesity and obesity-related diseases treatment

Along with social development and lifestyle changes, the number of overweight and obese patients worldwide is rising annually. Obesity is a chronic metabolic disease with complex etiology. Dipeptidyl peptidase IV (DPP-IV) is a novel adipokine with significantly elevated expression in the visceral fat of obese patients. DPP-IV is a molecule that regulates metabolic homeostasis and inflammatory processes. Through its enzymatic activity, it plays a significant part in achieving hypoglycemic and weight loss effects through various pathways. DPP-IV and DPP-IV inhibitors also have pleiotropic effects in modulating obesity-related diseases by reducing obesity-related inflammation, ameliorating inflammatory bowel disease (IBD), improving hepatic steatosis and lowering cardiovascular risk, and even decreasing the risk of novel coronavirus disease-19 (COVID-19). This paper reviews the mechanisms of action based on DPP-IV targets in obesity and metabolic homeostasis, as well as their active role in the treatment of chronic diseases associated with obesity.

Variation of modulation and expression of biomarkers associated with inflammation in bariatric surgery patients: A systematic review and meta-analysis

BACKGROUND

Bariatric surgery is an effective intervention that causes a series of metabolic changes related to inflammatory processes; however, the variation of biomarkers related to these processes is not entirely understood. Our objective was to investigate the variation of modulation and expression of biomarkers associated with inflammation in patients who underwent bariatric surgery.

METHODS

We searched the MEDLINE (via PubMed), EMBASE (via Elsevier), Cochrane Central Register of Controlled Trials, Latin American and Caribbean Literature on Health Sciences (via virtual health library), Cumulative Index to Nursing and Allied Health Literature (via EBSCO), Web of Science core collection, and Scopus (via Elsevier) databases, and the gray literature was examined from inception to January 2022. Three pairs of reviewers performed data screening, extraction, and quality assessment independently. Meta-analysis with random effects models was used for general, subgroup, and sensitivity analyses. The I2 statistic was used to assess heterogeneity between studies.

RESULTS

In total, 96 articles were included in this systematic review; of these, 87 studies met the criteria for the meta-analysis, involving 3,533 participants. Five biomarkers were included in the meta-analysis (tumor necrosis factor alpha; interleukin 6; leptin; interleukin 1 beta, and lipopolysaccharides). Only leptin showed a significant decrease in the first month after surgery (mean difference -20.71; [95% confidence interval: -28.10 to -13.32, P < .0001; I2 = 66.7%), with moderate heterogeneity. The 12 months after surgery showed a significant decrease in tumor necrosis factor alpha (mean difference -0.89; [95% confidence interval: -1.37 to -0.42], P = .0002; I2 = 94.7%), interleukin 6 (mean difference -1.62; [95% confidence interval: -1.95 to -1.29], P < .0001; I2 = 94.9%), leptin (mean difference -28.63; [95% confidence interval: -34.02 to -23.25], P < .0001; I2 = 92.7%), and interleukin 1 beta (mean difference -2.46; [95% confidence interval: -4.23 to -0.68], P = .006; I2 = 98.3%), all with high heterogeneity. The type of surgery did not show significant differences for the biomarkers at the first month and 12 months, and the results have not changed with high-quality studies. In the 12-month measurement, variations in tumor necrosis factor alpha and leptin were associated with body mass index.

CONCLUSION

The findings of this meta-analysis suggest that Roux-en-Y gastric bypass and sleeve gastrectomy bariatric surgeries are associated with a significant reduction in leptin at 1 month after bariatric surgical intervention and tumor necrosis factor alpha, leptin, and interleukin 1 beta after 12 months.

The postprandial secretion of peptide YY1-36 and 3-36 in obesity is differentially increased after gastric bypass versus sleeve gastrectomy

OBJECTIVES

Peptide tyrosine tyrosine (PYY) exists as two species, PYY1-36 and PYY3-36 , with distinct effects on insulin secretion and appetite regulation. The detailed effects of bariatric surgery on PYY1-36 and PYY3-36 secretion are not known as previous studies have used nonspecific immunoassays to measure total PYY. Our objective was to characterize the effect of sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) on fasting and postprandial PYY1-36 and PYY3-36 secretion using a newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay.

DESIGN AND SUBJECTS

Observational study in 10 healthy nonobese volunteers and 30 participants with obesity who underwent RYGB (n = 24) or SG (n = 6) at the Imperial Weight Centre [NCT01945840]. Participants were studied using a standardized mixed meal test (MMT) before and 1 year after surgery. The outcome measures were PYY1-36 and PYY3-36 concentrations.

RESULTS

Presurgery, the fasting and postprandial levels of PYY1-36 and PYY3-36 were low, with minimal responses to the MMT, and these did not differ from healthy nonobese volunteers. The postprandial secretion of both PYY1-36 and PYY3-36 at 1 year was amplified after RYGB, but not SG, with the response being significantly higher in RYGB compared with SG.

CONCLUSIONS

There appears to be no difference in PYY secretion between nonobese and obese volunteers at baseline. At 1 year after surgery, RYGB, but not SG, is associated with increased postprandial secretion of PYY1-36 and PYY3-36 , which may account for long-term differences in efficacy and adverse effects between the two types of surgery.

Changes in Gastric Inhibitory Polypeptide (GIP) After Roux-en-Y Gastric Bypass in Obese Patients: a Meta-analysis

This meta-analysis aimed to evaluate changes in GIP after RYGB in obese patients. We searched PubMed, EMBASE, and CENTRAL for relevant studies from database inception through July 2021. Articles were eligible for inclusion if they reported pre-operative and post-operative fasting GIP levels. We found fasting GIP levels had a decreasing tendency. The decrease in fasting glucose and postprandial GIP levels was also observed. Subgroup analysis indicated diabetic subjects tended to have a more obvious fasting GIP reduction compared to non-diabetic individuals. Meta-regression showed that the amount of weight loss (% total body weight), gastric pouch volume, alimentary limb length, and biliopancreatic limb length were not related to fasting GIP decrease. Fasting GIP levels decreased significantly after RYGB in obese people, especially in diabetic patients.