Mechanisms in bariatric surgery: Gut hormones, diabetes resolution, and weight loss

Greater durability of weight loss at ten years with gastric bypass compared to sleeve gastrectomy

INTRODUCTION

Sleeve gastrectomy (SG) and gastric bypass (GB) are the most commonly performed bariatric surgeries. However, there is insufficient data on which leads to greater long-term (10 year) weight loss.

METHODS

Subjects who underwent SG and GB from 2008-2013 were followed up at 2, 5, and 10 years post-operatively for weight and diabetes (DM) outcomes. Percentage total weight loss (%TWL), weight regain ( ≥ 20% from nadir) and DM remission rates were compared.

RESULTS

Subjects (n = 253) who underwent SG (60.9%) and GB (39.1%) were included. The mean age was 41.4 ± 10.6 y, 39.1% were male, and the mean body mass index was 42.1 ± 9.3 kg/m2 with no significant difference between groups. The GB group had a greater proportion of subjects with DM (83.8% vs 19.5%, p < 0.001). At 2 y, %TWL was comparable (GB: 22.3 ± 9.6%, SG: 22.6 ± 10.5%, p = 0.824). However, those who underwent GB had significantly higher %TWL at 5 y (GB: 21.5 ± 8.9%, SG 18.0 ± 11.3%, p = 0.029) and 10 y (GB: 21.0 ± 9.0%, SG: 15.4 ± 12.1%, p = 0.001). The rate of significant weight regain was higher amongst the SG group at both 5 y (SG: 14.7%, GB: 3.8%, p = 0.018) and 10 y (SG: 27.9%, GB: 13.7%, p = 0.037) post-operatively. On multiple linear regression, GB remained significantly associated with greater %TWL at 10 y compared to SG (b = 5.51; adjusted p-value = 0.013), after adjusting for age, sex, pre-operative BMI, pre-operative glycemic status, and surgery year. There was no difference in DM remission rates at 10 y (SG: 26.7%, GB: 19.1%, p = 0.385).

CONCLUSION

GB was able to produce greater %TWL and less weight regain than SG at 5 and 10 years post-operatively. There was no difference in long-term DM remission rates between the two surgeries.

Changes in food preferences and ingestive behaviors after glucagon-like peptide-1 analog treatment: techniques and opportunities

BACKGROUND

Glucagon-like peptide-1 (GLP-1) analogs are approved for the treatment of obesity in adults and adolescents. Reports have emerged that the weight loss effect of these medications may be related to changes in food preferences and ingestive behaviors following the treatment. Understanding the mechanisms which impact ingestive behavior could expand opportunities to develop more refined and personalized treatment options for obesity.

METHODS

Recent studies investigating the relationship between GLP-1 analogs and ingestive behaviors were retrieved from PubMed using the search terms: "obesity," "food preference," "taste," "ingestive behavior," "weight loss medication," "anti-obesity medication," "GLP-1 analog," "tirzepatide," "liraglutide," "semaglutide." Measurement tools were studied to compare variables used to assess food intake behavior. The main outcomes from each study were analyzed to evaluate the current standing and future directions of appetitive, ingestive, and consummatory behaviors and their association with GLP-1 analogs.

RESULTS

Thus far, studies have primarily explored the weight loss phase and report decreased short-term appetite and food intake upon treatment. However, research during the weight maintenance phase and objective measurements of food intake are notably sparse. Additionally, verbal reports have been primarily used to examine food intake, which can be susceptible to subjectivity.

CONCLUSIONS

Elucidating the relationship between GLP-1 analogs and ingestive behavior could reveal additional parameters which contribute to their anti-obesity effects. To better understand these mechanisms, it is imperative to consider objective measurements of food intake in future studies. Several measurement tools have been adapted to measure variables of food behavior in humans, and each must be carefully considered with their strengths and limitations to develop optimal investigations.

Glucagon-Like Peptide-1 Links Ingestion, Homeostasis, and the Heart

Glucagon-like peptide-1 (GLP-1), a hormone released from enteroendocrine cells in the distal small and large intestines in response to nutrients and other stimuli, not only controls eating and insulin release, but is also involved in drinking control as well as renal and cardiovascular functions. Moreover, GLP-1 functions as a central nervous system peptide transmitter, produced by preproglucagon (PPG) neurons in the hindbrain. Intestinal GLP-1 inhibits eating by activating vagal sensory neurons directly, via GLP-1 receptors (GLP-1Rs), but presumably also indirectly, by triggering the release of serotonin from enterochromaffin cells. GLP-1 enhances glucose-dependent insulin release via a vago-vagal reflex and by direct action on beta cells. Finally, intestinal GLP-1 acts on the kidneys to modulate electrolyte and water movements, and on the heart, where it provides numerous benefits, including anti-inflammatory, antiatherogenic, and vasodilatory effects, as well as protection against ischemia/reperfusion injury and arrhythmias. Hindbrain PPG neurons receive multiple inputs and project to many GLP-1R-expressing brain areas involved in reward, autonomic functions, and stress. PPG neuron-derived GLP-1 is involved in the termination of large meals and is implicated in the inhibition of water intake. This review details GLP-1's roles in these interconnected systems, highlighting recent findings and unresolved issues, and integrating them to discuss the physiological and pathological relevance of endogenous GLP-1 in coordinating these functions. As eating poses significant threats to metabolic, fluid, and immune homeostasis, the body needs mechanisms to mitigate these challenges while sustaining essential nutrient intake. Endogenous GLP-1 plays a crucial role in this "ingestive homeostasis."

Appetite-related Gut Hormone Responses to Feeding Across the Life Course

Appetite-related hormones are secreted from the gut, signaling the presence of nutrients. Such signaling allows for cross-talk between the gut and the appetite-control regions of the brain, influencing appetite and food intake. As nutritional requirements change throughout the life course, it is perhaps unsurprising that appetite and eating behavior are not constant. Changes in appetite-related gut hormones may underpin these alterations in appetite and eating. In this article, we review evidence of how the release of appetite-related gut hormones changes throughout the life course and how this impacts appetite and eating behaviour. We focus on hormones for which there is the strongest evidence of impact on appetite, food intake, and body weight: the anorexigenic glucagon like peptide-1, peptide tyrosine tyrosine, and cholecystokinin, and the orexigenic ghrelin. We consider hormone concentrations, particularly in response to feeding, from the very early days of life, through childhood and adolescence, where responses may reflect energy requirements to support growth and development. We discuss the period of adulthood and midlife, with a particular focus on sex differences and the effect of menstruation, pregnancy, and menopause, as well as the potential influence of appetite-related gut hormones on body composition and weight status. We then discuss recent advancements in our understanding of how unfavorable changes in appetite-related gut hormone responses to feeding in later life may contribute to undernutrition and a detrimental aging trajectory. Finally, we briefly highlight priorities for future research.

The role of nutrient sensing dysregulation in anorexia of ageing: The little we know and the much we don't

The age-related decline in appetite and food intake - termed "anorexia of ageing" - is implicated in undernutrition in later life and hence provides a public health challenge for our ageing population. Eating behaviour is controlled, in part, by homeostatic mechanisms which sense nutrient status and provide feedback to appetite control regions of the brain. Such feedback signals, propagated by episodic gut hormones, are dysregulated in some older adults. The secretory responses of appetite-related gut hormones to feeding are amplified, inducing a more anorexigenic signal which is associated with reduced appetite and food intake. Such an augmented response would indicate an increase in gut sensitivity to nutrients. Consequently, this review explores the role of gastrointestinal tract nutrient sensing in age-related appetite dysregulation. We review and synthesise evidence for age-related alterations in nutrient sensing which may explain the observed hormonal dysregulation. Drawing on what is known regarding elements of nutrient sensing pathways in animal models, in other tissues of the body, and in certain models of disease, we identify potential causal mechanisms including alterations in enteroendocrine cell number and distribution, dysregulation of cell signalling pathways, and changes in the gut milieu. From identified gaps in evidence, we highlight interesting and important avenues for future research.

The dual GLP-1/glucagon receptor agonist G49 mimics bariatric surgery effects by inducing metabolic rewiring and inter-organ crosstalk

Bariatric surgery is effective for the treatment and remission of obesity and type 2 diabetes, but pharmacological approaches which exert similar metabolic adaptations are needed to avoid post-surgical complications. Here we show how G49, an oxyntomodulin (OXM) analog and dual glucagon/glucagon-like peptide-1 receptor (GCGR/GLP-1R) agonist, triggers an inter-organ crosstalk between adipose tissue, pancreas, and liver which is initiated by a rapid release of free fatty acids (FFAs) by white adipose tissue (WAT) in a GCGR-dependent manner. This interactome leads to elevations in adiponectin and fibroblast growth factor 21 (FGF21), causing WAT beiging, brown adipose tissue (BAT) activation, increased energy expenditure (EE) and weight loss. Elevation of OXM, under basal and postprandial conditions, and similar metabolic adaptations after G49 treatment were found in plasma from patients with obesity early after metabolic bariatric surgery. These results identify G49 as a potential pharmacological alternative sharing with bariatric surgery hormonal and metabolic pathways.

Surgical or medical treatment of obesity-associated type 2 diabetes-an increasing clinical conundrum

In this editorial, we comment on the article by He et al, specifically in relation to the efficacy of bariatric surgery vs glucagon-like peptide-1 receptor agonist (GLP-1RA) therapy in the management of type 2 diabetes (T2D) associated with obesity. Bariatric surgery has now also been shown to be safe and effective in pre-teens and teenagers with obesity and T2D, but information on newer GLP-1RAs in these groups is predictably limited. In older individuals (age > 65 years), both bariatric surgery and GLP-1RA therapy improve cardiovascular outcomes. Bariatric surgery is not infrequently associated with post-operative postprandial hypoglycemia, which is not the case with GLP-1RAs and, paradoxically, there is evidence that GLP-1RAs may reduce both the frequency and severity of postprandial hypoglycemia. Comparative trials of the long-term efficacy of bariatric surgery and GLP-1RAs are indicated.

Gut-derived appetite hormones do not explain energy intake differences in humans following low-carbohydrate versus low-fat diets

OBJECTIVE

The objective of this study was to explore how dietary macronutrient composition influences postprandial appetite hormone responses and subsequent energy intake.

METHODS

A total of 20 adults (mean [SEM], age 30 [1] years, BMI 27.8 [1.3] kg/m2, n = 8 with normal weight, n = 6 with overweight, n = 6 with obesity) consumed a low-fat (LF) diet (10% fat, 75% carbohydrate) and a low-carbohydrate (LC) diet (10% carbohydrate, 75% fat) for 2 weeks each in an inpatient randomized crossover design. At the end of each diet, participants consumed isocaloric macronutrient-representative breakfast test meals, and 6-h postprandial responses were measured. Ad libitum energy intake was measured for the rest of the day.

RESULTS

The LC meal resulted in greater mean postprandial plasma active glucagon-like peptide-1 (GLP-1; LC: 6.44 [0.78] pg/mL, LF: 2.46 [0.26] pg/mL; p < 0.0001), total glucose-dependent insulinotropic polypeptide (GIP; LC: 578 [60] pg/mL, LF: 319 [37] pg/mL; p = 0.0004), and peptide YY (PYY; LC: 65.6 [5.6] pg/mL, LF: 50.7 [3.8] pg/mL; p = 0.02), whereas total ghrelin (LC: 184 [25] pg/mL, LF: 261 [47] pg/mL; p = 0.0009), active ghrelin (LC: 91 [9] pg/mL, LF: 232 [28] pg/mL; p < 0.0001), and leptin (LC: 26.9 [6.5] ng/mL, LF: 35.2 [7.5] ng/mL; p = 0.01) were lower compared with LF. Participants ate more during LC at lunch (244 [85] kcal; p = 0.01) and dinner (193 [86] kcal; p = 0.04), increasing total subsequent energy intake for the day compared with LF (551 [103] kcal; p < 0.0001).

CONCLUSIONS

In the short term, endogenous gut-derived appetite hormones do not necessarily determine ad libitum energy intake.

Outcomes of Single Anastomosis Sleeve Ileal (SASI) Bypass as an Alternative Procedure in Treating Obesity: An Updated Systematic Review and Meta-Analysis

PURPOSE

The Single Anastomosis Sleeve Ileal (SASI) bypass is a novel bariatric procedure that simplifies Santoro's procedure, balancing functional restriction and neuroendocrine modulation while preserving anatomy. We aim to conduct a single-arm meta-analysis of the SASI bypass to explore its moderate-term efficacy, as this might expand the available choices for surgeons to choose the best bariatric surgery that suits the patient's condition.

MATERIALS AND METHODS

We conducted a comprehensive search on PubMed, Scopus, EMBASE, and Cochrane to identify studies for the SASI bypass surgery focusing on outcomes such as %EWL, %TWL, remission rate of comorbidities, and complications. The statistical analysis was carried out using RStudio version 4.3.2. Heterogeneity was assessed using the Cochrane Q test and I2 statistics.

RESULTS

Our findings illuminate SASI's potency by undertaking a single-arm meta-analysis involving 1873 patients across 26 studies. At 12 months, we report a noteworthy % Excess Weight Loss (%EWL) (Mean 84.13; 95% CI 78.41-89.85; I2 = 95%), and % Total Weight Loss (%TWL) (Mean 35.17; 95% CI 32.30-38.04; I2 = 97%), highlighting SASI's efficacy on weight loss. Cumulative meta-analyses supported these findings. More weight loss was observed with a 250 cm common limb and a greater than 3 cm anastomosis. An 88.28% remission rate in type 2 diabetes mellitus (95% CI 79.74-95.03; I2 = 84%) at 12 months was observed. Beyond weight outcomes, SASI impacts comorbidities with a good safety profile.

CONCLUSION

Our study positions the SASI bypass as a good alternative option. However, long-term efficacy is yet to be explored in the future.

The Role of Dietary Intake in the Weight Loss Outcomes of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy: A Systematic Review and Meta-analysis

The relationship between postoperative dietary intake and weight loss after bariatric surgery remains unclear. We performed a systematic review and meta-analysis of studies published between January 2000 and May 2023, reporting weight loss outcomes, and dietary intake before and after Roux-en-Y gastric bypass and sleeve gastrectomy. A total of 42 studies were included. There was no detectable difference in dietary intake between the two procedures. Roux-en-Y gastric bypass induced an average decrease in energy intake of 886 kcal/day at 12-month post-surgery; however, there was no correlation between daily energy intake and weight loss. These findings show a substantial reduction of energy intake in the first year after bariatric surgery but do not support a link between lower energy intake and greater weight loss.

Long-Term Effectiveness and Outcomes of Bariatric Surgery: A Comprehensive Review of Current Evidence and Emerging Trends

Obesity is a global epidemic associated with an increased risk of severe health conditions such as type 2 diabetes, cardiovascular diseases, and certain cancers. Bariatric surgery has become a pivotal treatment for severe obesity, offering significant improvements in weight loss and comorbidity resolution. This comprehensive review aims to assess the long-term effectiveness and outcomes of various bariatric surgical procedures, highlighting current evidence and emerging trends in the field. We extensively reviewed the literature, including randomized controlled trials, cohort studies, and meta-analyses, to evaluate long-term weight loss, resolution of obesity-related comorbidities, quality of life (QoL), and complications associated with different bariatric procedures. Bariatric surgery has demonstrated substantial and sustained weight loss over the long term, with varying degrees of effectiveness among different procedures. Gastric bypass and sleeve gastrectomy are associated with significant improvements in comorbidities such as type 2 diabetes and hypertension. QoL outcomes are generally positive, improving physical health, mental well-being, and social functioning. However, long-term complications, including nutritional deficiencies and the need for reoperations, remain challenges. Emerging trends such as minimally invasive techniques and nonsurgical interventions show promise in enhancing patient outcomes. Bariatric surgery remains a highly effective intervention for managing severe obesity and its related health issues. While long-term outcomes are generally favorable, continued advancements in surgical techniques and postoperative care are crucial for optimizing results and minimizing complications. Future research should focus on personalized approaches to patient management and the development of novel treatment modalities to further improve outcomes in the long term.

Purple sweet potato anthocyanins normalize the blood glucose concentration and restore the gut microbiota in mice with type 2 diabetes mellitus

Background

This study investigated the effects of purple sweet potato anthocyanins (PSPA) in a type 2 diabetes mellitus (T2DM) mouse model.

Methods

Sixty-five male mice were randomly divided into one control group and four experimental groups, which were fed with a high-fat diet and intraperitoneally injected with streptozotocin (STZ) to induce T2DM. The model mice were treated with 0 (M), 227.5 (LP), 455 (MP), or 910 (HP) mg/kg PSPA for ten days. ELISA, 16S rRNA sequencing, and hematoxylin and eosin staining were used to assess blood biochemical parameters, gut microbial composition, and liver tissue structure, respectively.

Results

The FBG concentration was significantly decreased in the LP (6.32 ± 1.05 mmol/L), MP (6.32 ± 1.05 mmol/L), and HP (5.65 ± 0.83 mmol/L) groups; the glycosylated hemoglobin levels were significantly decreased in the HP group (14.43 ± 7.12 pg/mL) compared with that in the M group (8.08 ± 1.04 mmol/L; 27.20 ± 7.72 pg/mL; P < 0.05). The PSPA treated groups also increased blood glutathione levels compared with M. PSPA significantly affected gut microbial diversity. The Firmicutes/Bacteroidetes ratio decreased by 38.9 %, 49.2 %, and 15.9 % in the LP, MP, and HP groups compared with that in the M group (0.62). The PSPAs treated groups showed an increased relative abundance of Lachnospiraceae_Clostridium, Butyricimonas, and Akkermansia and decreased abundance of nine bacterial genera, including Staphylococcus.

Conclusion

PSPA reduced blood glucose levels, increased serum antioxidant enzymes, and optimized the diversity and structure of the gut microbiota in mice with T2DM.

Impact of Gastrojejunostomy Anastomosis Diameter on Weight Loss Following Laparoscopic Gastric Bypass: A Systematic Review

Laparoscopic Roux-en-Y gastric bypass (RYGB) is crucial for significant weight reduction and treating obesity-related issues. However, the impact of gastrojejunostomy (GJ) anastomosis diameter on weight loss remains unclear. We investigate this influence on post-RYGB weight loss outcomes. A systematic search was conducted. Six studies met the inclusion criteria, showing varied GJ diameters and follow-up durations (1-5 years). Smaller GJ diameters generally correlated with greater short-to-medium-term weight loss, with a threshold beyond which complications like stenosis increased. Studies had moderate-to-low bias risk, emphasizing the need for precise GJ area quantification post-operation. This review highlights a negative association between smaller GJ diameters and post-RYGB weight loss, advocating for standardized measurement techniques. Future research should explore intra-operative and AI-driven methods for optimizing GJ diameter determination.

Differences in the Impact of Obesity and Bariatric Surgery on Patients Hospitalized for Atrial Flutter and Atrial Fibrillation: A Nationwide Analysis, 2016-2020

BACKGROUND

The "obesity paradox" claims that although obesity is a risk factor for atrial fibrillation, obese patients have lower inpatient mortality when admitted due to atrial fibrillation. This study aims to analyze if the obesity paradox still holds true after weight loss from bariatric surgery.  Methods: This study analyzed discharge data from the National Inpatient Sample, 2016-2020. Patients admitted due to atrial fibrillation or atrial flutter, with or without obesity, and with or without a past medical history of bariatric surgery were identified using ICD-10-CM and ICD-10-PCS codes. The primary outcome was mortality. Secondary outcomes included length of stay, resource utilization, necessity for endotracheal intubation, and necessity for cardioversion. STATA v.13 was used for univariate and multivariate analysis (StataCorp LLC, Texas, USA).

RESULTS

Among 2,292,194 patients who had a primary diagnosis of atrial fibrillation or atrial flutter, 494,830 were obese and 25,940 had bariatric surgery. Mortality was not significantly different in post-bariatric surgery patients when compared to the general population (OR 0.76; 95% [CI 0.482-1.2; p=0.24]). Mortality was significantly lower in obese patients when compared to the general population (OR 0.646; 95% [CI 0.583-0.717; p<0.001]). Therefore, post-bariatric surgery patients had a higher mortality than obese patients when compared to the general population. Obese patients spent more days in the hospital (regression 0.219; 95% [CI 0.19-0.248, p<0.001]), had higher resource utilization (regression 3491.995; 95% [CI 2870.085-4113.905, p<0.001]), more cardioversions (OR 1.434; 95% [CI 1.404-1.465; p<0.001]), and no difference in endotracheal intubation rate (OR 1.02; 95% [CI 0.92-1.127; p=0.724]) when compared to the general population. Post-bariatric patients had no difference in length of stay (regression -0.053; 95% [CI -0.137-0.031; p=0.218]) and resource utilization (regression 577.297; 95% [CI -1069.801-2224.396; p=0.492]), fewer endotracheal intubations (OR 0.583; 95% [CI 0.343-0.99; p=0.046]), and more cardioversions (OR 1.223; 95% [CI 1.134-1.32; p<0.001]) when compared to the general population.

CONCLUSION

Compared to the general population, post-bariatric patients had higher inpatient mortality than obese patients when admitted due to atrial fibrillation or atrial flutter. This research reinforces the presence of the obesity paradox following bariatric surgery with respect to mortality.

Gut peptides before and following Roux-En-Y gastric bypass: A systematic review and meta-analysis

A systematic search was conducted in Medline Ovid, Embase, Scopus, and Cochrane Central Register of Controlled Trials up until March 2021 following PRISMA guidelines. Studies included evaluated ghrelin, GLP-1, PYY or appetite sensation via visual analogue scales (VASs) before and after Roux-en-Y gastric bypass (RYGB) in adults. A multilevel model with random effects for study and follow-up time points nested in study was fit to the data. The model included kcal consumption as a covariate and time points as moderators. Among the 2559 articles identified, k = 47 were included, among which k = 19 evaluated ghrelin, k = 40 GLP-1, k = 22 PYY, and k = 8 appetite sensation. Our results indicate that fasting ghrelin levels are decreased 2 weeks post-RYGB (p = 0.005) but do not differ from baseline from 6 weeks to 1-year post-RYGB. Postprandial ghrelin and fasting GLP-1 levels were not different from pre-surgical values. Postprandial levels of GLP-1 increased significantly from 1 week (p < 0.001) to 2 years post-RYGB (p < 0.01) compared with pre-RYGB. Fasting PYY increased at 6 months (p = 0.034) and 1 year (p = 0.029) post-surgery; also, postprandial levels increased up to 1 year (p < 0.01). Insufficient data on appetite sensation were available to be meta-analyzed.

Metabolomics of Mice with Type 2 Diabetes and Nonalcoholic Fatty Liver Treated by Acupuncture

Introduction

To investigate the effects of acupuncture on endogenous metabolites in the liver of type 2 diabetes mellitus (T2DM) with nonalcoholic fatty liver disease (NAFLD) mice-based metabolomics.

Methods

Proton nuclear magnetic resonance (1H-NMR) metabolomics combined with multivariate statistical analysis and univariate analysis were used to analyze the changes of endogenous metabolites in the liver of mice in each group and to provide new clinical ideas for acupuncture in the treatment of glycolipid metabolism disorders caused by T2DM and NAFLD.

Results

After 4 weeks of continuous treatment, fasting blood glucose (FBG), insulin (INS), total cholesterol (TC), and triglyceride (TG) decreased significantly in mice in the acupuncture treatment group (ATG), and the content of liver glycogen increased significantly. Based on 1H-NMR metabolomic analysis, a total of 47 metabolites were identified in the liver of T2DM with NAFLD mice, of which eight metabolites: UDP-N-acetylglucosamine, adenosine, glutamate, isoleucine, ATP, 3-hydroxybutyric acid, NADP+, and leucine were significantly altered by acupuncture treatment. Through the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, it is found that acupuncture has an intervention effect on five metabolic pathways, mainly involving amino acid metabolism, energy metabolism, and oxidative stress.

Conclusion

Our study shows that acupuncture can regulate the liver metabolism mode of T2DM in NAFLD mice. It can reduce blood glucose and lipid accumulation in the liver, and these findings provide a new idea and theoretical basis for acupuncture in the treatment of diseases related to glucose and lipid metabolism.

Advances in obesity pharmacotherapy; learning from metabolic surgery and beyond

Currently, metabolic surgery (MS) constitutes the most effective means for durable weight loss of clinically meaningful magnitude, type 2 diabetes remission and resolution of non-alcoholic steatohepatitis, as well as other obesity-related comorbidities. Accumulating evidence on the mechanisms through which MS exerts its actions has highlighted the altered secretion of hormonally active peptides of intestinal origin with biological actions crucial to energy metabolism as key drivers of MS clinical effects. The initial success of glucagon-like peptide-1 (GLP-1) receptor agonists regarding weight loss and metabolic amelioration have been followed by the development of unimolecular dual and triple polyagonists, additionally exploiting the effects of glucagon and/or glucose-dependent insulinotropic polypeptide (GIP) which achieves a magnitude of weight loss approximating that of common MS operations. Through the implementation of such therapies, the feasibility of a "medical bypass", namely the replication of the clinical effects of MS through non-surgical interventions may be foreseeable in the near future. Apart from weight loss, this approach ought to be put to the test also regarding other clinical outcomes, such as liver steatosis and steatohepatitis, cardiovascular disease, and overall prognosis, on which MS has a robustly demonstrated impact. Besides, a medical bypass as an alternative, salvage, or combination strategy to MS may promote precision medicine in obesity therapeutics.

Food cravings after bariatric surgery: comparing laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass

BACKGROUND

Research suggests that food choices, preferences, and tastes change after bariatric surgery, but evidence regarding changes in food cravings is mixed.

OBJECTIVES

The primary aim of this cohort study was to compare food cravings during the first year following bariatric surgery in patients who had undergone sleeve gastrectomy (SG) versus Roux-en-Y gastric bypass (RYGB).

SETTING

Integrated multispecialty health system, United States.

METHODS

Patients aged ≥ 18 years seen between May 2017 and July 2019, provided informed consent, completed the Food Craving Inventory (FCI), and had ≥ 1 year of follow-up after undergoing primary SG or RYGB were included in the study. Secondary data captured included psychological and behavioral measures. Preoperative and postoperative (3, 6, 9, and 12 months) FCI scores of patients who underwent SG and RYGB were compared.

RESULTS

Some attrition occurred postoperatively (N = 187 at baseline, 141 at 3 months, 108 at 6 months, 89 at 9 months, and 84 at 12 months). No significant relationship between pre- or postoperative food cravings and surgery type was found except on the carbohydrate subscale. Patients with higher preoperative food addiction symptoms were not more likely to experience an earlier reoccurrence of food cravings during the first 12 months after surgery. Likewise, patients with higher levels of preoperative depression and anxiety were not more likely to have early reoccurrence of food cravings during the first 12 months after surgery; however, those with higher PHQ9 scores at baseline had uniformly higher food craving scores at all timepoints (pre-surgery, 3 m, 6 m, 9 m, and 12 m).

CONCLUSIONS

Results suggest that food cravings in the year after bariatric surgery are equivalent by surgery type and do not appear to be related to preoperative psychological factors or eating behaviors.

LEVEL OF EVIDENCE

Level III: Evidence obtained from well-designed cohort.

Postprandial plasma GLP-1 levels are elevated in individuals with postprandial hypoglycaemia following Roux-en-Y gastric bypass - a systematic review

BACKGROUND AND AIMS

Bariatric surgery is the most effective treatment in individuals with obesity to achieve remission of type 2 diabetes. Post-bariatric surgery hypoglycaemia occurs frequently, and management remains suboptimal, because of a poor understanding of the underlying pathophysiology. The glucoregulatory hormone responses to nutrients in individuals with and without post-bariatric surgery hypoglycaemia have not been systematically examined.

MATERIALS AND METHODS

The study protocol was prospectively registered with PROSPERO. PubMed, EMBASE, Web of Science and the Cochrane databases were searched for publications between January 1990 and November 2021 using MeSH terms related to post-bariatric surgery hypoglycaemia. Studies were included if they evaluated individuals with post-bariatric surgery hypoglycaemia and included measurements of plasma glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), insulin, C-peptide and/or glucagon concentrations following an ingested nutrient load. Glycated haemoglobin (HbA1c) was also evaluated. A random-effects meta-analysis was performed, and Hedges' g (standardised mean difference) and 95% confidence intervals were reported for all outcomes where sufficient studies were available. The τ2 estimate and I2 statistic were used as tests for heterogeneity and a funnel plot with the Egger regression-based test was used to evaluate for publication bias.

RESULTS

From 377 identified publications, 12 were included in the analysis. In all 12 studies, the type of bariatric surgery was Roux-en-Y gastric bypass (RYGB). Comparing individuals with and without post-bariatric surgery hypoglycaemia following an ingested nutrient load, the standardised mean difference in peak GLP-1 was 0.57 (95% CI, 0.32, 0.82), peak GIP 0.05 (-0.26, 0.36), peak insulin 0.84 (0.44, 1.23), peak C-peptide 0.69 (0.28, 1.1) and peak glucagon 0.05 (-0.26, 0.36). HbA1c was less in individuals with hypoglycaemia - 0.40 (-0.67, -0.12). There was no evidence of substantial heterogeneity in any outcome except for peak insulin: τ2 = 0.2, I2 = 54.3. No publication bias was evident.

CONCLUSION

Following RYGB, postprandial peak plasma GLP-1, insulin and C-peptide concentrations are greater in individuals with post-bariatric surgery hypoglycaemia, while HbA1c is less. These observations support the concept that antagonism of GLP-1 would prove beneficial in the management of individuals with hypoglycaemia following RYGB.PROSPERO Registration Number: CRD42021287515.

Milestones in the journey towards addressing obesity; Past trials and triumphs, recent breakthroughs, and an exciting future in the era of emerging effective medical therapies and integration of effective medical therapies with metabolic surgery

The 21st century is characterized by an increasing incidence and prevalence of obesity and the burden of its associated comorbidities, especially cardiometabolic diseases, which are reaching pandemic proportions. In the late '90s, the "black box" of adipose tissue and energy homeostasis was opened with the discovery of leptin, transforming the adipose tissue from an "inert fat-storage organ" to the largest human endocrine organ and creating the basis on which more intensified research efforts to elucidate the pathogenesis of obesity and develop novel treatments were based upon. Even though leptin was eventually not proven to be the "standalone magic bullet" for the treatment of common/polygenic obesity, it has been successful in the treatment of monogenic obesity syndromes. Additionally, it shifted the paradigm of treating obesity from a condition due to "lack of willpower" to a disease due to distinct underlying biological mechanisms for which specific pharmacotherapies would be needed in addition to lifestyle modification. Subsequently, the melanocortin pathway proved to be an equally valuable pathway for the pharmacotherapy of obesity. Melanocortin receptor agonists have recently been approved for treating certain types of syndromic obesity. Other molecules- such as incretins, implicated in energy and glucose homeostasis- are secreted by the gastrointestinal tract. Glucagon-like peptide 1 (GLP-1) is the most prominent one, with GLP-1 analogs approved for common/polygenic obesity. Unimolecular combinations with other incretins, e.g., GLP-1 with gastric inhibitory polypeptide and/or glucagon, are expected to be approved soon as more effective pharmacotherapies for obesity and its comorbidities. Unimolecular combinations with other compounds and small molecules activating the receptors of these molecules are currently under investigation as promising future pharmacotherapies. Moreover, metabolic and bariatric surgery has also demonstrated impressive results, especially in the case of morbid obesity. Consequently, this broadening therapeutic armamentarium calls for a well-thought-after and well-coordinated multidisciplinary approach, for instance, through cardiometabolic expertise centers, that would ideally address effectively and cost-effectively obesity and its comorbidities, providing tangible benefits to large segments of the population.

Discordance between gut-derived appetite hormones and energy intake in humans

Gut-derived hormones affect appetite and are thought to play an important role in body weight regulation. Dietary macronutrient composition can influence gut-derived appetite hormone concentrations, thereby providing theoretical basis for why some diets might facilitate weight loss better than others. We investigated postprandial gut-derived appetite hormones in 20 inpatient adults after 2 weeks of eating either a low carbohydrate (LC) or a low fat (LF) diet followed by the alternate diet in random order. A LC meal resulted in significantly greater postprandial GLP-1, GIP, and PYY but lower ghrelin compared to an isocaloric LF meal (all p≤0.02). However, differences in gut-derived appetite hormones were incommensurate with subsequent ad libitum energy intake over the rest of the day, which was 551±103 kcal (p<0.0001) greater with the LC as compared to the LF diet. The effects of gut-derived appetite hormones on ad libitum energy intake can be dominated by other diet-related factors, at least in the short-term.

Bariatric Artery Embolization for Obese Patients. An Up-to-Date Review

Overweight and obesity are one of public health's major problems in the world. Conservative treatment with exercise, diet and pharmacotherapy is often ineffective, especially in the long term. Bariatric surgery is the gold standard method for a sustained long-term weight loss. Recently the endovascular technique of bariatric artery embolization (BAE) has been studied as an obesity and overweight treatment, with promising results. The goal of this article is to analyze the rationale behind BAE and to provide an up-to-date analysis of its strengths and limitation in comparison with bariatric surgery as a treatment for obesity.

Increased Glucagon Immunoreactivity in a Rat Model of Diet-induced Obesity following Sleeve Gastrectomy

OBJECTIVE

Bariatric surgery is currently the most effective treatment for obesity, and procedures such as Roux-en Y gastric bypass and sleeve gastrectomy (SG) also result in rapid improvements in insulin sensitivity and glucose tolerance. In addition, these procedures cause changes in the secretion of various gut-derived hormones. The role these hormones play in the mechanism of the beneficial effects of bariatric surgery is still debated, but nonetheless, their importance provides inspiration for novel obesity-targeted pharmacotherapies.

METHODS

Male Sprague Dawley rats were fed either regular chow or a cafeteria diet to induce obesity. A sub-group of the obese animals then underwent either sham surgery or SG.

RESULTS

Following a 4-week recovery period, SG rats weighed significantly less than obese or sham-operated rats. Improvements in glucose tolerance and insulin sensitivity also occurred in the SG group, but these were not always statistically significant. We measured the intracellular lipid content of liver samples and found that obese rats showed signs of non-alcoholic fatty liver disease, which were significantly ameliorated by SG. There were significantly higher glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) responses to a standard mixed meal in the SG group, as well as paradoxically higher glucagon secretion.

CONCLUSION

These data highlight the need for more specific anti-glucagon antibodies to characterize the changes in proglucagon-derived peptide concentrations that occur following SG. Further studies are required to determine whether these peptides contribute to the therapeutic effects of SG.

Testing for Protein Leverage in Patients with Gastric Bypass: A Pilot Study

INTRODUCTION

Protein leverage (PL) is the phenomenon whereby a dominant appetite for protein drives overconsumption of energy with a decline in the ratio of protein to fat and carbohydrate in the diet. PL has been independently verified in several randomized control trials, and its predictions are supported by diet surveillance data. Our aim in the present study was to test whether surgical intervention through gastric bypass will ameliorate the PL effect.

METHODS

Ten patients with gastric bypass (2-5 years postsurgical time) were given ad libitum access to study food comprising 10%, 15%, or 25% protein and no access to other foods for 3 days while controlling food palatability and variety. Food intake was measured, and energy and nutrient intakes were calculated. Body weight, blood chemistry, lipid profile, hormones (insulin, leptin, and ghrelin), and creatinine were determined before and after each experimental period.

RESULTS

The gastric bypass patients in our study did not show evidence for protein intake regulation as predicted under PL but ate to constant total energy intake on the 10%, 15%, and 25% protein diets with protein intake varying significantly. Patients lost weight in the three study periods, but significant weight loss was observed only on the 15% protein diet.

CONCLUSION

Our results suggest that gastric bypass might disengage the PL mechanism, thus ameliorating an appetite-specific mechanism that drives energy overconsumption in modern food environments.

Exploring the underlying mechanisms of obesity and diabetes and the potential of Traditional Chinese Medicine: an overview of the literature

Obesity and diabetes are closely related metabolic disorders that have become major public health concerns worldwide. Over the past few decades, numerous studies have explored the underlying mechanisms of these disorders and identified various risk factors, including genetics, lifestyle, and dietary habits. Traditional Chinese Medicine (TCM) has been increasingly recognized for its potential to manage obesity and diabetes. Weight loss is difficult to sustain, and several diabetic therapies, such as sulfonylureas, thiazolidinediones, and insulin, might make it harder to lose weight. While lifestyle changes should be the primary approach for people interested in lowering weight, drugs are also worth investigating. Since some of the newer glucose-lowering medications that cause weight loss, such as glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and sodium-glucose cotransporter 2 inhibitors (SGLT2i), are additionally utilized or are under consideration for use as anti-obesity drugs, the frontier between glucose-lowering medication and weight loss drugs appears to be shifting. This review provides an overview of the literature on the underlying mechanisms of obesity and diabetes and the prospect of TCM in their management. We discuss the various TCM interventions, including acupuncture, herbal medicine, and dietary therapy, and their effects on metabolic health. We also highlight the potential of TCM in regulating gut microbiota, reducing inflammation, and improving insulin sensitivity. The findings suggest that TCM may provide a promising approach to preventing and managing obesity and diabetes. However, further well-designed studies are needed to confirm the efficacy and safety of TCM interventions and to elucidate their underlying mechanisms of action.

Testing replicability of the relationship between weight suppression and binge eating in three non-clinical samples varying in lifetime weight history

OBJECTIVE

Increased weight suppression, the difference between an individual's highest and current weight at present height, predicts binge eating among eating disorder samples. Less is known about this relationship in non-clinical samples of individuals with a history of higher weight.

METHODS

Lifetime highest BMI was tested as a moderator of the relationship between weight suppression and binge eating in three independent samples (N = 1740).

RESULTS

At the bivariate level, weight suppression was not associated with binge eating in any sample (p's ≥ 0.20). Lifetime highest BMI moderated the relationship between weight suppression and binge eating in Sample 1 (p = .04), such that greater weight suppression was associated with lower binge eating among those with a history of higher weight (i.e., BMI = 40 kg/m2). In Samples 2 and 3, the lifetime highest BMI by weight suppression interaction term was not significant and dropped from the model (p's = 0.10-0.12). Accounting for age, gender, and lifetime highest BMI, greater weight suppression was associated with lower binge eating scores (p's < 0.04). A meta-analysis combining results revealed a small but significant interaction effect (r = 0.07, p = .02).

CONCLUSIONS

Findings highlight the importance of investigating the generalizability of eating disorder risk and maintenance theories across the weight spectrum. Weight loss may not increase risk for binge eating among those with a history of higher weight. Future work should replicate and extend this finding using longitudinal designs. More research is needed to elucidate which weight loss motivations and/or behaviors are most closely linked to binge eating.

Evaluation of hormonal and circulating inflammatory biomarker profiles in the year following bariatric surgery

Background

Bariatric surgery (BS) has a superior effect on reducing body weight and fat in patients with morbid obesity. As a result, BS mitigates obesity-related complications such as type 2 diabetes (T2D). However, few studies have shown the mechanism underlying diabetes remission after surgery. This study aimed to investigate the differences in serum hormone and inflammatory cytokine levels related to diabetes before surgery and during 12 months of follow-up in Korean patients with obesity.

Methods

The study participants were patients with morbid obesity (n=63) who underwent sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) between 2016 - 2017 at seven tertiary hospitals in Korea. The patients were followed for 1 year after surgery.

Results

Sixty-three patients had significant weight loss after surgery and showed improvements in clinical parameters and hormonal and inflammatory profiles. Among them, 23 patients who were diabetic preoperatively showed different remission after surgery. The levels of inflammation-related clinical parameters changed significantly in the remission group, and serum inflammatory cytokine and hormones significantly decreased at certain points and showed an overall decreasing trend.

Conclusions

Our study found postoperative changes of factors in blood samples, and the changes in hormones secreted from the three major metabolic tissue (pancreas, adipose, and gut) along with the differences in multi-origin inflammatory cytokines between remission and non-remission groups provide a path for understanding how the effect of BS in improving glucose metabolism is mediated.

Future therapies for obesity

Obesity is a chronic disease associated with increased morbidity and mortality. Bariatric surgery can lead to sustained long-term weight loss (WL) and improvement in multiple obesity-related complications, but it is not scalable at the population level. Over the past few years, gut hormone-based pharmacotherapies for obesity and type 2 diabetes mellitus (T2DM) have rapidly evolved, and combinations of glucagon-like peptide 1 (GLP1) with other gut hormones (glucose-dependent insulinotropic polypeptide (GIP), glucagon, and amylin) as dual or triple agonists are under investigation to enhance and complement the effects of GLP1 on WL and obesity-related complications. Tirzepatide, a dual agonist of GLP1 and GIP receptors, marks a new era in obesity pharmacotherapy in which a combination of gut hormones could approach the WL achieved with bariatric surgery. In this review, we discuss emerging obesity treatments with a focus on gut hormone combinations and the concept of a multimodal approach for obesity management.

Association between GLP-1R gene polymorphism and dyslipidemia in Chinese patients with type 2 diabetes mellitus: a case-control study

OBJECTIVE

To evaluate the relationship between GLP-1R gene polymorphisms and type 2 diabetes mellitus with dyslipidemia and without dyslipidemia in China.

METHODS

A total of 200 patients with Type 2 Diabetes Mellitus (T2DM) were included in this study, including 115 with dyslipidemia and 85 without dyslipidemia. We used Sanger double deoxygenation terminal assay and PCR-RFLP to detect genotype of the GLP-1R rs10305420 and rs3765467 loci. T-test was used to analyze the association between gene polymorphisms and lipid indicators. SHEsis online analysis software was used to analyze the linkage balance effect of loci, and SPSS 26 was used to calculate the gene interaction by dominant model.

RESULTS

The genotype distribution of the two loci in the sample of this study was in accordance with Hardy-weinberg equilibrium. There were significant differences in the genotype distribution and allele frequency of rs3765467 between T2DM patients with and without dyslipidemia (GG 52.9%, GA+AA 47.1% vs. GG 69.6%, GA+AA 30.4%; P = 0.017). Under the dominant model, the effects of rs3765467 A allele and rs10305420 T allele on dyslipidemia had multiplicative interactions (P = 0.016) and additive interactions (RERI = 0.403, 95% CI [-2.708 to 3.514]; AP = 0.376, 95% CI [-2.041, 2.793]). Meanwhile, HbA_1c levels in rs3765467 A allele carriers (GA+AA) were found to be significantly lower than those in patients with GG genotype (P = 0.006).

CONCLUSION

The rs3765467 (G/A) variant is associated with the incidence of dyslipidemia, and G allele may be a risk factor for dyslipidemia.

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.

FAM3D: A gut secreted protein and its potential in the regulation of glucose metabolism

The number of diabetic patients is rising globally and concomitantly so do the diabetes associated complications. The gut secretes a variety of proteins to control blood glucose levels and/or food intake. As the drug class of GLP-1 agonists is based on a gut secreted peptide and the positive metabolic effects of bariatric surgery are at least partially mediated by gut peptides, we were interested in other gut secreted proteins which have yet to be explored. In this respect we identified the gut secreted protein FAM3D by analyzing sequencing data from L- and epithelial cells of VSG and sham operated as well as chow and HFD fed mice. FAM3D was overexpressed in diet induced obese mice via an adeno-associated virus (AAV), which resulted in a significant improvement of fasting blood glucose levels, glucose tolerance and insulin sensitivity. The liver lipid deposition was reduced, and the steatosis morphology was improved. Hyperinsulinemic clamps indicated that FAM3D is a global insulin sensitizer and increases glucose uptake into various tissues. In conclusion, the current study demonstrated that FAM3D controls blood glucose levels by acting as an insulin sensitizing protein and improves hepatic lipid deposition.

No Evidence That Circulating GLP-1 or PYY Are Associated with Increased Satiety during Low Energy Diet-Induced Weight Loss: Modelling Biomarkers of Appetite

Bariatric surgery and pharmacology treatments increase circulating glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), in turn promoting satiety and body weight (BW) loss. However, the utility of GLP-1 and PYY in predicting appetite response during dietary interventions remains unsubstantiated. This study investigated whether the decrease in hunger observed following low energy diet (LED)-induced weight loss was associated with increased circulating 'satiety peptides', and/or associated changes in glucose, glucoregulatory peptides or amino acids (AAs). In total, 121 women with obesity underwent an 8-week LED intervention, of which 32 completed an appetite assessment via a preload challenge at both Week 0 and Week 8, and are reported here. Visual analogue scales (VAS) were administered to assess appetite-related responses, and blood samples were collected over 210 min post-preload. The area under the curve (AUC_0-210), incremental AUC (iAUC_0-210), and change from Week 0 to Week 8 (∆) were calculated. Multiple linear regression was used to test the association between VAS-appetite responses and blood biomarkers. Mean (±SEM) BW loss was 8.4 ± 0.5 kg (-8%). Unexpectedly, the decrease in ∆AUC_0-210 hunger was best associated with decreased ∆AUC_0-210 GLP-1, GIP, and valine (p < 0.05, all), and increased ∆AUC_0-210 glycine and proline (p < 0.05, both). The majority of associations remained significant after adjusting for BW and fat-free mass loss. There was no evidence that changes in circulating GLP-1 or PYY were predictive of changes in appetite-related responses. The modelling suggested that other putative blood biomarkers of appetite, such as AAs, should be further investigated in future larger longitudinal dietary studies.

Effects of subtotal pancreatectomy and long-term glucose and lipid overload on insulin secretion and glucose homeostasis in minipigs

INTRODUCTION

Nowadays, there are no strong diabetic pig models, yet they are required for various types of diabetes research. Using cutting-edge techniques, we attempted to develop a type 2 diabetic minipig model in this study by combining a partial pancreatectomy (Px) with an energetic overload administered either orally or parenterally.

METHODS

Different groups of minipigs, including Göttingen-like (GL, n = 17) and Ossabaw (O, n = 4), were developed. Prior to and following each intervention, metabolic assessments were conducted. First, the metabolic responses of the Göttingen-like (n = 3) and Ossabaw (n = 4) strains to a 2-month High-Fat, High-Sucrose diet (HFHSD) were compared. Then, other groups of GL minipigs were established: with a single Px (n = 10), a Px combined with a 2-month HFHSD (n = 6), and long-term intraportal glucose and lipid infusions that were either preceded by a Px (n = 4) or not (n = 4).

RESULTS

After the 2-month HFHSD, there was no discernible change between the GL and O minipigs. The pancreatectomized group in GL minipigs showed a significantly lower Acute Insulin Response (AIR) (18.3 ± 10.0 IU/mL after Px vs. 34.9 ± 13.7 IU/mL before, p < .0005). In both long-term intraportal infusion groups, an increase in the Insulinogenic (IGI) and Hepatic Insulin Resistance Indexes (HIRI) was found with a decrease in the AIR, especially in the pancreatectomized group (IGI: 4.2 ± 1.9 after vs. 1.5 ± 0.8 before, p < .05; HIRI (×10^-5 ): 12.6 ± 7.9 after vs. 3.8 ± 4.3 before, p < .05; AIR: 24.4 ± 13.7 µIU/mL after vs. 43.9 ± 14.5 µIU/mL before, p < .005). Regardless of the group, there was no fasting hyperglycemia.

CONCLUSIONS

In this study, we used pancreatectomy followed by long-term intraportal glucose and lipid infusions to develop an original minipig model with metabolic syndrome and early signs of glucose intolerance. We reaffirm the pig's usefulness as a preclinical model for the metabolic syndrome but without the fasting hyperglycemia that characterizes diabetes mellitus.

The role of weight control in the management of type 2 diabetes mellitus: Bariatric surgery

Diabetes mellitus is one of the major epidemics in the United States. It is heavily associated with obesity and multiple metabolic derangements that lead to long term morbidity, mortality as well as financial burden. Although medical therapy has been the mainstay in the management of diabetes mellitus, there remains a large portion of this patient population which struggles to obtain adequate glycemic control and long-term weight control with medical management alone. Bariatric surgery is a powerful tool in combating diabetes mellitus and affects glucose homeostasis through a variety of pathways. While it does provide a durable pathway for weight loss, improvement in glucose homeostasis is not only affected by the weight loss seen after bariatric surgery. Changes in gut hormone secretion, insulin regulation, and gut microbial composition also affect how these operations improve glucose homeostasis. Through improvement in the management of diabetes mellitus, comorbidities including cardiovascular disease, in turn demonstrate improvement. In this article, we will discuss the role of bariatric (metabolic) surgery as it relates to long term weight loss and the impact that weight loss has on improvement in diabetes mellitus.

Complex regulatory effects of gut microbial short-chain fatty acids on immune tolerance and autoimmunity

Immune tolerance deletes or suppresses autoreactive lymphocytes and is established at multiple levels during the development, activation and effector phases of T and B cells. These mechanisms are cell-intrinsically programmed and critical in preventing autoimmune diseases. We have witnessed the existence of another type of immune tolerance mechanism that is shaped by lifestyle choices, such as diet, microbiome and microbial metabolites. Short-chain fatty acids (SCFAs) are the most abundant microbial metabolites in the colonic lumen and are mainly produced by the microbial fermentation of prebiotics, such as dietary fiber. This review focuses on the preventive and immunomodulatory effects of SCFAs on autoimmunity. The tissue- and disease-specific effects of dietary fiber, SCFAs and SCFA-producing microbes on major types of autoimmune diseases, including type I diabetes, multiple sclerosis, rheumatoid arthritis and lupus, are discussed. Additionally, their key regulatory mechanisms for lymphocyte development, tissue barrier function, host metabolism, immunity, autoantibody production, and inflammatory effector and regulatory lymphocytes are discussed. The shared and differential effects of SCFAs on different types and stages of autoimmune diseases are discussed.

Ecological momentary assessment of changes in eating behaviors, appetite, and other aspects of eating regulation in Roux-en-Y gastric bypass and sleeve gastrectomy patients

Bariatric surgery can have profound impacts on eating behaviors and experiences, yet most prior research studying these changes has relied on retrospective self-report measures with limited precision and susceptibility to bias. This study used smartphone-based ecological momentary assessment (EMA) to evaluate the trajectory of change in eating behaviors, appetite, and other aspects of eating regulation in 71 Roux-en-Y gastric bypass and sleeve gastrectomy patients assessed preoperatively and at 3, 6, and 12-months postoperative. For some outcomes, results showed a consistent and similar pattern for SG and RYGB where consumption of sweet and high-fat foods and hunger, desire to eat, ability to eat right now, and satisfaction with amount eaten all improved from pre-to 6-months post-surgery with some degree of deterioration at 12-months post-surgery. By contrast, other variables, largely related to hedonic hunger and craving and desire for specific foods, showed less consistent patterns that differed by surgery type. While the findings suggest an overall pattern of improvement in eating patterns following bariatric surgery, they also highlight how a return to preoperative habits may begin as early as 6 months after surgery. Additional research is needed to understand mechanisms that promote changes in eating behavior after surgery, and how best to intervene to preserve beneficial effects.

Reduction of Plasma BCAAs following Roux-en-Y Gastric Bypass Surgery Is Primarily Mediated by FGF21

Type 2 diabetes (T2D) is a challenging health concern worldwide. A lifestyle intervention to treat T2D is difficult to adhere, and the effectiveness of approved medications such as metformin, thiazolidinediones (TZDs), and sulfonylureas are suboptimal. On the other hand, bariatric procedures such as Roux-en-Y gastric bypass (RYGB) are being recognized for their remarkable ability to achieve diabetes remission, although the underlying mechanism is not clear. Recent evidence points to branched-chain amino acids (BCAAs) as a potential contributor to glucose impairment and insulin resistance. RYGB has been shown to effectively lower plasma BCAAs in insulin-resistant or T2D patients that may help improve glycemic control, but the underlying mechanism for BCAA reduction is not understood. Hence, we attempted to explore the mechanism by which RYGB reduces BCAAs. To this end, we randomized diet-induced obese (DIO) mice into three groups that underwent either sham or RYGB surgery or food restriction to match the weight of RYGB mice. We also included regular chow-diet-fed healthy mice as an additional control group. Here, we show that compared to sham surgery, RYGB in DIO mice markedly lowered serum BCAAs most likely by rescuing BCAA breakdown in both liver and white adipose tissues. Importantly, the restored BCAA metabolism following RYGB was independent of caloric intake. Fasting insulin and HOMA-IR were decreased as expected, and serum valine was strongly associated with insulin resistance. While gut hormones such as glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) are postulated to mediate various surgery-induced metabolic benefits, mice lacking these hormonal signals (GLP-1R/Y2R double KO) were still able to effectively lower plasma BCAAs and improve glucose tolerance, similar to mice with intact GLP-1 and PYY signaling. On the other hand, mice deficient in fibroblast growth factor 21 (FGF21), another candidate hormone implicated in enhanced glucoregulatory action following RYGB, failed to decrease plasma BCAAs and normalize hepatic BCAA degradation following surgery. This is the first study using an animal model to successfully recapitulate the RYGB-led reduction of circulating BCAAs observed in humans. Our findings unmasked a critical role of FGF21 in mediating the rescue of BCAA metabolism following surgery. It would be interesting to explore the possibility of whether RYGB-induced improvement in glucose homeostasis is partly through decreased BCAAs.

Increased meal-induced neurotensin response predicts successful maintenance of weight loss - Data from a randomized controlled trial

BACKGROUND

The gut derived anorexigenic hormone neurotensin (NT) is upregulated after bariatric surgery which may contribute to the sustained weight loss. In contrast, diet-induced weight loss is most often followed by weight regain. We therefore investigated whether diet-induced weight loss impacts levels of circulating NT in mice and humans and whether NT levels predicts body weight change after weight loss in humans.

METHODS

In vivo mice study: Obese mice were fed ad-libitum or a restricted diet (40-60 % of average food intake) for 9 days to obtain similar weight loss as observed in the human study. At termination, intestinal segments, the hypothalamus and plasma were collected for histological, real time PCR, and radioimmunoassay (RIA) analysis.

CLINICAL TRIAL

Plasma samples from 42 participants with obesity, completing an 8-week low-calorie diet in a randomized controlled trial, were analyzed. Plasma NT was measured by RIA at fasting and during a meal test before and after diet-induced weight loss and after one year of intended weight maintenance.

RESULTS

In obese mice, food restriction-induced body weight loss of 14 % was associated with a 64 % reduction in fasting plasma NT (p < 0.0001). In the mouse duodenum (p = 0.07) and jejunum (p < 0.05), NT tissue concentration was decreased without tissue atrophy indicative of a physiological downregulation. In the mouse hypothalamus a downregulation of Pomc (p < 0.01) along with upregulation of Npy (p < 0.001) and Agrp (p < 0.0001) expression was found after restricted feeding in support of increased hunger after diet-induced weight loss. Therefore, we investigated the NT response in humans undergoing weight loss maintenance. In humans, similar to the mice, the low-calorie diet induced weight loss of 13 % body weight was associated with 40 % reduction in fasting plasma NT levels (p < 0.001). Meal-induced NT peak responses were greater in humans who lost additional weight during the 1 year maintenance phase compared to participants who regained weight (p < 0.05).

CONCLUSION

Diet-induced weight loss decreased fasting plasma NT levels in both humans and mice with obesity, and regulated hunger-associated hypothalamic gene expression in mice. Meal-induced NT responses were greater in humans who lost additional weight during the 1 year maintenance phase compared to participants who regained weight. This indicates that increased peak secretion of NT after weight loss may contribute to successful maintenance of weight loss.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02094183.

The Importance of Endogenously Secreted GLP-1 and GIP for Postprandial Glucose Tolerance and β-Cell Function After Roux-en-Y Gastric Bypass and Sleeve Gastrectomy Surgery

Enhanced secretion of glucagon-like peptide 1 (GLP-1) seems to be essential for improved postprandial β-cell function after Roux-en-Y gastric bypass (RYGB) but is less studied after sleeve gastrectomy (SG). Moreover, the role of the other major incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), is relatively unexplored after bariatric surgery. We studied the effects of separate and combined GLP-1 receptor (GLP-1R) and GIP receptor (GIPR) blockade during mixed-meal tests in unoperated (CON), SG-operated, and RYGB-operated people with no history of diabetes. Postprandial GLP-1 concentrations were highest after RYGB but also higher after SG compared with CON. In contrast, postprandial GIP concentrations were lowest after RYGB. The effect of GLP-1R versus GIPR blockade differed between groups. GLP-1R blockade reduced β-cell glucose sensitivity and increased or tended to increase postprandial glucose responses in the surgical groups but had no effect in CON. GIPR blockade reduced β-cell glucose sensitivity and increased or tended to increase postprandial glucose responses in the CON and SG groups but had no effect in the RYGB group. Our results support that GIP is the most important incretin hormone in unoperated people, whereas GLP-1 and GIP are equally important after SG, and GLP-1 is the most important incretin hormone after RYGB.

Single-anastomosis Sleeve Jejunal: a Mid-term Follow-up Report of a New Surgical Technique

INTRODUCTION

Single anastomosis sleeve ileal bypass (SASI) is a combined bariatric metabolic technique, in which few studies have shown its outcomes efficacy. However, this technique has a high risk of malnutrition due to long biliopancreatic limb. Single anastomosis sleeve jejunal bypass (SASJ) has a shorter limb. Therefore, it seems to have a lower risk of nutrient deficiency. Furthermore, this technique is relatively new, and little is known about the efficacy and safety of SASJ. We aim to report our mid-term follow-up of SASJ from a high-volume center for bariatric metabolic surgery in the Middle East region.

METHODS

For the current study, the 18-month follow-up data of 43 patients with severe obesity who underwent SASJ was collected. The primary outcome measures were demographic data, weight change variables according to ideal body mass index (BMI) of 25 kg/m² at 6, 12, and 18 months, laboratory assessments, remission of obesity-associated medical problems, and other potential bariatric metabolic complications after the surgery.

RESULTS

No patient was lost due to follow-up. After 18 months, patients lost 43.4 ± 11 kg of their weight and 68 ± 14% of their excess weight, and their BMI decreased from 44.9 ± 4.7 to 28.6 ± 3.8 kg/m² (p < 0.001). The percentage of total weight loss till 18 months was 36.3%. The T2D remission rate at 18 months was 100%. Patients neither faced deficiency in significant markers for nutrition state nor represented major bariatric metabolic surgery complications.

CONCLUSION

SASJ bypass achieved satisfactory weight loss and remissions in obesity-associated medical problems within 18 months after surgery without major complications and malnutrition.

Bariatric surgery and weight loss in the short- and long-term: Evidence from NHANES 2015-2018

The present study aimed to examine short- and long-term weight change in a nationally representative sample of US adults who reportedly underwent bariatric surgery. Individuals aged 20-64 at survey from the US National Health and Nutrition Examination Survey 2015-2018 were included in the analyses (n = 6776). The primary comparison groups include 62 participants who underwent bariatric surgery, 1531 eligible but did not receive surgery, and 5183 not eligible for bariatric surgery. After adjusting for demographic characteristics and comorbidity, adults who reported receiving bariatric surgery were 5.0 times (4.0-6.0) more likely to achieve at least 20% weight loss from maximum weight relative to those who were eligible but reported no surgery. The likelihood appeared to be higher when surgery was performed within 10 years (short-term, PR 5.5, 95% CI: 4.0, 7.0) relative to surgeries that were performed for 10 or more years (long-term, PR 3.6, 95% CI: 2.0, 5.3). In this nationally representative sample of US adults, respondents who received bariatric surgery achieved substantial and significant weight loss compared with those who were eligible and did not receive bariatric surgery. Weight loss appeared to be most apparent in the short term and persisted over the long term.

Downregulation of hepatic lncRNA Gm19619 improves gluconeogenesis and lipogenesis following vertical sleeve gastrectomy in mice

Long non-coding RNAs (lncRNAs) are emerging important epigenetic regulators in metabolic processes. Whether they contribute to the metabolic effects of vertical sleeve gastrectomy (VSG), one of the most effective treatments for sustainable weight loss and metabolic improvement, is unknown. Herein, we identify a hepatic lncRNA Gm19619, which is strongly repressed by VSG but highly up-regulated by diet-induced obesity and overnight-fasting in mice. Forced transcription of Gm19619 in the mouse liver significantly promotes hepatic gluconeogenesis with the elevated expression of G6pc and Pck1. In contrast, AAV-CasRx mediated knockdown of Gm19619 in high-fat diet-fed mice significantly improves hepatic glucose and lipid metabolism. Mechanistically, Gm19619 is enriched along genomic regions encoding leptin receptor (Lepr) and transcription factor Foxo1, as revealed in chromatin isolation by RNA purification (ChIRP) assay and is confirmed to modulate their transcription in the mouse liver. In conclusion, Gm19619 may enhance gluconeogenesis and lipid accumulation in the liver.

Fucoidan from Laminaria japonica Ameliorates Type 2 Diabetes Mellitus in Association with Modulation of Gut Microbiota and Metabolites in Streptozocin-Treated Mice

Chronic diseases have been a leading cause of death worldwide, and polysaccharide supplementation is an effective therapeutic strategy for chronic diseases without adverse effects. In this study, the beneficial effect of Laminaria japonica fucoidan (LJF) on type 2 diabetes mellitus (T2DM) was evaluated in streptozocin-treated mice. LJF ameliorated the symptoms of T2DM in a dose-dependent manner, involving reduction in weight loss, water intake, triglyceride, blood glucose, cholesterol and free fatty acids, and increases in high-density lipoprotein cholesterol, catalase, glucagon-like peptide-1, and superoxide dismutase. In addition, LJF regulated the balance between insulin resistance and insulin sensitivity, reduced islet necrosis and β-cell damage, and inhibited fat accumulation in T2DM mice. The protective effect of LJF on T2DM can be associated with modulation of the gut microbiota and metabolites, e.g., increases in Lactobacillus and Allobaculum. Untargeted and targeted metabolomics analysis showed that the microbiota metabolite profile was changed with LJF-induced microbiota alterations, mainly involving amino acids, glutathione, and glyoxylate and dicarboxylate metabolism pathways. This study indicates that LJF can be used as a prebiotic agent for the prevention and treatment of diabetes and microbiota-related diseases.

Effect of Bariatric Surgery on Metabolic Syndrome, Framingham Risk Scores and Thyroid Function during One-Year Follow-Up: A Saudi Retrospective Study

Bariatric surgery (BS) has been demonstrated to achieve sustained weight loss with significant metabolic improvement, including a reduction in cardiovascular disease and diabetes. The aim of this retrospective study is to measure the effect of BS on the Framingham risk score (FRS) and metabolic syndrome (MetS) among patients who underwent bariatric surgery. Additionally, we determine the effect of BS on thyroid-stimulating hormone (TSH) among euthyroid obese patients. A retrospective follow-up study was conducted at King Abdullah Medical City, Makkah, Saudi Arabia. A total of 160 patients underwent BS and completed one-year follow-up visits. Medical history, anthropometric, biochemical, and hormonal parameters were evaluated at baseline and 3−12 months after BS. The International Diabetes Federation (IDF) criteria were used to diagnose MetS. There was a significant decrease in systolic blood pressure (SBP), diastolic blood pressure (DBP), glycated hemoglobin (Hba1c), TSH, low-density lipoprotein (LDL), triglycerides, and total cholesterol (p < 0.001). A significant decrease was seen in MetS, BMI, FRS, SBP, DBP, Hba1c, LDL, triglycerides, cholesterol, and liver enzymes, with a significant increase in high-density lipoprotein levels 12 months postoperatively (p < 0.001). At 12 months, the prevalence of MetS, DM, and HTN and the FRS significantly decreased from 72.5%, 43.1%, 78.1%, and 11.4 to 16.3%, 9.4%, 22.5%, and 5.4, respectively. In addition to achieving substantial weight loss, BS improves MetS prevalence and cardiovascular risk profiles.

Remission as an Emerging Therapeutic Target in Type 2 Diabetes in the Era of New Glucose-Lowering Agents: Benefits, Challenges, and Treatment Approaches

Type 2 diabetes mellitus (T2DM) is a progressive disease with a growing prevalence, associated with an increased risk of complications. The introduction of new classes of antidiabetic drugs into clinical practice has dramatically changed the landscape of diabetes therapy. However, despite the progress made in the pharmacotherapy of T2DM, mitigating the burden of the disease on individuals, societies and health care systems remains a challenge. Remission has recently emerged as a therapeutic target in T2DM, achievable through a wide range of interventions. Recent studies have shown that extensive lifestyle changes, such as weight reduction, bariatric surgery, and intensive glucose lowering therapy, can prompt the remission of diabetes, but some unanswered questions remain regarding its long-term effects on diabetic complications. Metabolic surgery and novel classes of glucose-lowering medications are currently the most effective interventions to induce weight loss and by extension remission in patients with diabetes; however, the ideal strategy to achieve the long-term maintenance of remission remains doubtful. In this narrative review, we discuss the available therapeutic approaches to target the remission of diabetes through personalized multimodal care, based on the latest evidence.

Examining weight bias before and/or after bariatric surgery: A systematic review

Research examining weight bias in the bariatric population, who may be at greater risk of weight stigma, is scarce. The present study aimed to systematically review the literature for quantitative evidence that explores the medical, psychosocial, and behavioral sequelae associated with experienced, internalized, and/or externalized weight bias in patients seeking or who have undergone bariatric surgery. Five databases were systematically searched for English peer-reviewed quantitative studies, which examined weight bias in a sample of individuals seeking or who had undergone bariatric surgery. Risk of bias was assessed. Twenty-nine studies were included, of which 13 examined internalized weight bias, 12 examined experienced weight bias, 4 examined both, and 0 examined externalized weight bias. Most studies were cross-sectional, and the results showed high risk of bias. The results suggested that both experienced and internalized weight bias were associated with a host of negative psychosocial, behavioral, and medical sequelae. The findings of this review underscore the need for more rigorous research to better understand the relationship between weight bias and bariatric surgery, particularly longitudinally. Future patients may benefit from research developing interventions for reducing weight bias prior to and following bariatric surgery in order to reduce the associated negative correlates and improve outcomes.

Glucagon-like peptide-1 effect on β-cell function varies according to diabetes remission status after Roux-en-Y gastric bypass

AIMS

The contribution of endogenous glucagon-like peptide (GLP)-1 to β-cell function after Roux-en-Y gastric bypass surgery (RYGB) is well established in normoglycaemic individuals, but not in those with postoperative hyperglycaemia. We, therefore, studied the effect of GLP-1 on β-cell function in individuals with varying degrees of type 2 diabetes mellitus (T2D) control after RYGB.

MATERIALS AND METHODS

Glucose, insulin secretion rates, β-cell glucose sensitivity and glucagon were measured during an oral glucose tolerance test before (saline only) and at 3, 12 and 24 months after RYGB with and without infusion of the GLP-1 receptor blocker exendin9-39 (EX9). The cohort was retrospectively classified based on T2D remission (REM) status at the latest study time point: REM (n = 5), persistent T2D (n = 8), or impaired glucose tolerance (n = 16).

RESULTS

EX9 blunted the increase in β-cell glucose sensitivity at 3 months (-44.1%, p < .001) and 12 months (-43.3%, p < .001), but not at 24 months (-12.4%, p = .243). EX9 enhanced postprandial glucagon concentrations by 62.0% at 3 months (p = .008), 46.5% at 12 months (p = .055), and 30.4% at 24 months (p = .017). EX9 counterintuitively decreased glucose concentrations at 3 months in the entire cohort (p < .001) but had no effect on glycaemia at 12 and 24 months in persistent T2D and impaired glucose tolerance; it minimally worsened glycaemia in REM at 12 months.

CONCLUSIONS

GLP-1 blockade reversed the improvement in β-cell function observed after RYGB, but this effect varied temporally and by REM status. GLP-1 blockade transiently and minimally worsened glycaemia only in REM, and lowered postprandial glucose values at 3 months, regardless of REM status.

Differential effects of RYGB surgery and best medical treatment for obesity-diabetes on intestinal and islet adaptations in obese-diabetic ZDSD rats

Modification of gut-islet secretions after Roux-En-Y gastric bypass (RYBG) surgery contributes to its metabolic and anti-diabetic benefits. However, there is limited knowledge on tissue-specific hormone distribution post-RYGB surgery and how this compares with best medical treatment (BMT). In the present study, pancreatic and ileal tissues were excised from male Zucker-Diabetic Sprague Dawley (ZDSD) rats 8-weeks after RYGB, BMT (daily oral dosing with metformin 300mg/kg, fenofibrate 100mg/kg, ramipril 1mg/kg, rosuvastatin 10mg/kg and subcutaneous liraglutide 0.2mg/kg) or sham operation (laparotomy). Insulin, glucagon, somatostatin, PYY, GLP-1 and GIP expression patterns were assessed using immunocytochemistry and analyzed using ImageJ. After RYGB and BMT, body weight and plasma glucose were decreased. Intestinal morphometry was unaltered by RYGB, but crypt depth was decreased by BMT. Intestinal PYY cells were increased by both interventions. GLP-1- and GIP-cell counts were unchanged by RYGB but BMT increased ileal GLP-1-cells and decreased those expressing GIP. The intestinal contents of PYY and GLP-1 were significantly enhanced by RYGB, whereas BMT decreased ileal GLP-1. No changes of islet and beta-cell area or proliferation were observed, but the extent of beta-cell apoptosis and islet integrity calculated using circularity index were improved by both treatments. Significantly decreased islet alpha-cell areas were observed in both groups, while beta- and PYY-cell areas were unchanged. RYGB also induced a decrease in islet delta-cell area. PYY and GLP-1 colocalization with glucagon in islets was significantly decreased in both groups, while co-staining of PYY with glucagon was decreased and that with somatostatin increased. These data characterize significant cellular islet and intestinal adaptations following RYGB and BMT associated with amelioration of obesity-diabetes in ZDSD rats. The differential responses observed and particularly those within islets, may provide important clues to the unique ability of RYGB to cause diabetes remission.