Gut adaptation after metabolic surgery and its influences on the brain, liver and cancer

Gut microbiota alterations induced by Roux-en-Y gastric bypass result in glucose-lowering by enhancing intestinal glucose excretion

Roux-en-Y gastric bypass (RYGB) results in glucose-lowering in patients with type 2 diabetes mellitus (T2DM) and may be associated with increased intestinal glucose excretion. However, the contribution of intestinal glucose excretion to glycemic control after RYGB and its underlying mechanisms are not fully elucidated. Here, we confirmed that intestinal glucose excretion significantly increased in obese rats after RYGB, which was negatively correlated with postoperative blood glucose levels. Moreover, we also found that the contribution of Biliopancreatic limb length, an important factor affecting glycemic control after RYGB, to the improvement of glucose metabolism after RYGB attributed to the enhancement of intestinal glucose excretion. Subsequently, we further determined through multiple animal models that intestinal glucose excretion is physiological rather than pathological and plays a crucial role in maintaining glucose homeostasis in the body. Finally, we employed germ-free mice colonized with fecal samples from patients and rats to demonstrate that enhanced intestinal glucose excretion after RYGB is directly modulated by the surgery-induced changes in the gut microbiota. These results indicated that the gut microbiota plays a direct causal role in the hypoglycemic effect of RYGB by promoting intestinal glucose excretion, which may provide new insights for developing gut microbiota-based therapies for T2DM.

Exploring post-bariatric plasma metabolic changes using ATR-FTIR spectroscopy: Clinical insights and molecular perspectives

Bariatric surgery offers effective treatment of obesity, yet the full metabolic response of the organism remains unclear. Attenuated Total Reflection Fourier Transform Infrared spectroscopy (ATR-FTIR) allows to track the most detailed biochemical alterations in biofluids on a molecular level. This study aimed to utilize ATR-FTIR spectroscopy for monitoring changes of the metabolic profile of plasma in post-bariatric surgery patients and compare this profile to healthy individuals. Twenty patients with morbid obesity underwent bariatric procedures, resulting in improvement of anthropometric parameters. Laboratory biomarkers showed favorable changes: decreased triglycerides and glucose. PCA analysis of ATR-FTIR spectroscopy data revealed evolution of the plasma metabolic parameters towards those which characterize the healthy group, while the metabolic profile in the baseline group was different - lipid-associated infrared bands primarily drove this differentiation. Semiquantitative analysis of the selected bands revealed distinct spectral profiles with increased total lipid contributions in baseline as compared to follow-up and control. In turn, protein conformation showed increased β-sheet/α-helix ratios and altered secondary protein structures in follow-up. Tyrosine-ascribed region intensity attained the lowest value in baseline. C-O moieties and polysaccharides were elevated in follow-up. Alterations in protein structures were potentially influenced by supplementation and inflammation resolution, while lower tyrosine levels in obesity suggest oxidative stress involvement. Above findings highlight FTIR's potential in revealing impact of bariatric surgery on various elements of the metabolic profile. The multifaceted insight on plasma composition provided by FTIR shows significant improvements of this metabolic profile in post-surgery patients already six months after the intervention.

Effect of weight loss following Roux-en-Y gastric bypass on cancer risk: A Mendelian randomization study

Cancer incidence and development are strongly correlated with obesity, however there is insufficient data to support a causal relationship between intentional weight loss and the prevention or promotion of cancer. We investigated the causal relationship between weight loss following Roux-en-Y gastric bypass (RYGB) and the incidence of 18 cancers using Mendelian randomization (MR). A genome-wide association studies (GWAS) data related to weight loss following RYGB from the GWAS catalog database were used as exposure, and GWAS data related to 18 cancers from the Medical Research Council integrative epidemiology unit open GWAS project were used as outcomes. In order to investigate the causal relationship between exposure and results, we used a two-sample MR approach. The primary analysis technique was inverse variance weighting, with weighted median, and MR-Egger regression utilized as supplemental techniques to confirm the findings. Heterogeneity and horizontal pleiotropy were investigated using a variety of sensitivity studies, including the Cochran Q test, MR-Egger regression pleiotropy test, MR pleiotropy residual sum and outlier, and leave-one-out analysis. We included a total of 4 single-nucleotide polymorphisms as instrumental variables through rigorous quality control screening. Under the limitations of Bonferroni correction threshold (P < 2.78 × 10-3), our results suggest that the weight loss following RYGB has a significant causal relationship with a reduced risk of breast (odds ratio [OR]: 0.784; 95% confidence interval [CI]: 0.762-0.808; P = 2.167e-58) and lung cancer (OR: 0.992; 95% CI: 0.987-0.997; P = .0023), and a potential causal relationship with a decreased risk of hematological cancer (OR: 0.9998462; 95% CI: 0.9997088-0.9999836; P = .028) and an increased risk of cervical cancer (OR: 1.000123; 95% CI: 1.0000313-1.000215; P = .009). Sensitivity analysis confirms the robustness of our analysis results. Genetically predicted weight loss following RYGB has significant causal effects in reducing the risk of breast and lung cancer. It also has potential benefits in lowering the risk of hemotological cancers and increasing the risk of cervical cancer. Considering the limitations of our study, the reliability of its results and the underlying mechanisms require further investigation.

Optimal Bilio-Pancreatic Limb (BPL) Length in One Anastomosis Gastric Bypass (OAGB) Surgery

BACKGROUND

One Anastomosis Gastric Bypass (OAGB) is a modification of Mason's loop bypass procedure, which has become a well-established procedure in the field of Bariatric and Metabolic surgery (BMS). However, the optimal length of Biliopancreatic Limb (BPL) in OAGB remains an ongoing debate.

OBJECTIVE

This review aims to analyse the current trends and evidence regarding different BPL lengths in OAGB and their impact on outcomes.

METHODS

A comprehensive literature search using search terms, 'One Anastomosis Gastric Bypass', 'Mini-Gastric Bypass', 'Biliopancreatic Limb', and 'Small bowel limb' was conducted. The articles were extracted and critically appraised for various outcomes including weight loss, comorbidities resolution, nutritional deficiencies, complications and quality of life.

RESULTS

There appears to be a direct relationship between length of the BPL and the incidence of malnutrition. Longer BPL lengths (> 200 cm) are associated with a higher risk of malnutrition. Shorter BPL lengths (150-200 cm), particularly 150 cm, have shown promising outcomes.

CONCLUSION

Shorter BPL lengths offer potential advantages by reducing nutritional risks associated with OAGB. Further research with long-term follow-up is needed to investigate the efficacy of even shorter BPL lengths (< 150 cm).

Smart control lipid-based nanocarriers for fine-tuning gut hormone secretion

Modulating the endogenous stores of gastrointestinal hormones is considered a promising strategy to mimic gut endocrine function, improving metabolic dysfunction. Here, we exploit mouse and human knock-in and knockout intestinal organoids and show that agents used as commercial lipid excipients can activate nutrient-sensitive receptors on enteroendocrine cells (EECs) and, when formulated as lipid nanocarriers, can bestow biological effects through the release of GLP-1, GIP, and PYY from K and L cells. Studies in wild-type, dysglycemic, and gut Gcg knockout mice demonstrated that the effect exerted by lipid nanocarriers could be modulated by varying the excipients (e.g., nature and quantities), the formulation methodology, and their physiochemical properties (e.g., size and composition). This study demonstrates the therapeutic potential of using nanotechnology to modulate release of multiple endogenous hormones from the enteroendocrine system through a patient-friendly, inexpensive, and noninvasive manner.

[Sleeve gastrectomy for the surgical management of obesity at the Essos Hospital Center (Yaoundé, Cameroon): a retrospective case series study evaluating medium-term weight loss]

While the prevalence of overweight and obesity is rising in Africa, the practice of bariatric surgery remains limited in our country, Cameroon. Weight loss outcomes following sleeve gastrectomy (SG), the most widely used bariatric surgery technique worldwide, have not yet been studied in our context. The medical records of all patients who underwent SG in our surgery department between January 1, 2016, and September 30, 2020, were reviewed retrospectively. The primary outcome studied was medium-term weight loss, one year after surgery. Weight loss was calculated using the postoperative body mass index (BMI) and the percentage of excess weight loss (%EWL). Reinhold criteria were used to assess the %EWL. We collected data from the medical records of 21 patients, of whom 19 (90.5%) were female. The average age of patients was 40.3±10.8 years, with a mean BMI of 44.9±7.4 kg/m2. All patients had at least one obesity-related comorbidity. All procedures were performed laparoscopically, without conversion, with a mean duration of 192.2±52.8 min. One year after surgery, the mean BMI was 32.51±3.7 kg/m2 and the mean %EWL was 63.35±6.5%. According to Reinhold's criteria, the %EWL was considered satisfactory. In our context, SG provides satisfactory results for medium-term weight loss.

The role of FGF19 in metabolic regulation: insights from preclinical models to clinical trials

Fibroblast growth factor 19 (FGF19) is a hormone synthesized in enterocytes in response to bile acids. This review explores the pivotal role of FGF19 in metabolism, addressing the urgent global health concern of obesity and its associated pathologies, notably type 2 diabetes. The intriguing inverse correlation between FGF19 and body mass or visceral adiposity, as well as its rapid increase following bariatric surgery, emphasizes its potential as a therapeutic target. This article meticulously examines the impact of FGF19 on metabolism by gathering evidence primarily derived from studies conducted in animal models or cell lines, using both FGF19 treatment and genetic modifications. Overall, these studies demonstrate that FGF19 has antidiabetic and antiobesogenic effects. A thorough examination across metabolic tissues, including the liver, adipose tissue, skeletal muscle, and the central nervous system, is conducted, unraveling the intricate interplay of FGF19 across diverse organs. Moreover, we provide a comprehensive overview of clinical trials involving an FGF19 analog called aldafermin, emphasizing promising results in diseases such as nonalcoholic steatohepatitis and diabetes. Therefore, we aim to foster a deeper understanding of FGF19 role and encourage further exploration of its clinical applications, thereby advancing the field and offering innovative approaches to address the escalating global health challenge of obesity and related metabolic conditions.

Diffusion tensor imaging findings in the hunger and satiety centers of the brain after bariatric surgery: a preliminary study

PURPOSE

To investigate the alterations in the diffusion tensor imaging (DTI) parameters measured in the hunger and satiety centers of the brain before and after bariatric surgery (BS) in morbidly obese patients.

METHODS

Fourty morbidly obese patients were evaluated before and after BS. Mean diffusivity (MD) and fractional anisotropy (FA) values were calculated from 14 related brain locations, and the DTI parameters were analyzed.

RESULTS

After the BS, the mean BMI of the patients decreased from 47.53 ± 5.21 to 31.48 ± 4.21. The MD and FA values in the all of the hunger and satiety centers was found statistically significant different in the pre-surgery period compared to the post-surgery period (for each; p-value < 0.001).

CONCLUSION

The FA and MD changes after BS may be attributed to reversible neuroinflammatory alterations in the hunger and satiety centers. Decreased MD and FA values after BS may be explained by the neuroplastic structural recovery in the related brain locations.

Evaluation of the white matter integrity in morbidly obese patients before and after bariatric surgery; a diffusion tensor imaging study

PURPOSE

To investigate the difference in FA (Fractional anisotropy), ADC (Apparent diffusion coefficient), RD (Radial diffusivity) and AD (axial diffusivity) values of white matter (WM) tracts in morbidly obese subjects before and after bariatric surgery (BS).

MATERIALS AND METHODS

A group of thirty-nine morbidly obese subjects are evaluated before and 4-6 months after BS. ADC, FA, RD and AD values of 17 distinct neuroanatomic localizations are measured and DTI parameters are analyzed.

RESULTS

Following the BS, the patients' mean BMI decreased from 47.665.21 to 31.723.97. A significant difference is displayed between the pre-surgery and post-surgery FA values of SLF, SFOF, ALIC, fornix, ILF, CST, MCP (p = 0.010, p < 0.001, p = 0.048, p = 0.014, p = 0.012, p = 0.012, p = 0.040 respectively). Following BS, decrease in FA values in the mentioned areas are detected. ADC values obtained from MCP are significantly lower in the post-BS period compared to pre-BS period (p = 0.018). There was a statistically significant difference between the pre-surgery and post-surgery AD values of SLF, SFOF, ILF, ALIC, EC, CST, and MCP (p = 0.001, p = 0.022, p = 0.001, p = 0.011, p = 0.001, p = 0.000, p = 0.000, respectively). Following the BS, AD values of the SLF, SFOF, ILF, ALIC, EC, CST, and MCP are decreased. RD values measured from GCC are significantly lower in the post-BS period compared to pre-BS period (p = 0.008).

CONCLUSION

Our study supported the hypothesis of the BS-induced reversibility of the low-grade inflammation in WM tracts in the morbidly obese group following BS. Our DTI results may represent the subacute period findings of the reversal of low-grade inflammation after BS.

Bariatric surgery in the prevention of obesity-associated cancers: mechanistic implications

Obesity is associated with an increased risk of at least 13 different cancers, as well as worse cancer outcomes and increased cancer mortality. As rates continue to rise both in the United States and worldwide, obesity is poised to become the leading lifestyle-related risk factor for cancer. Currently, the most effective treatment for patients with severe obesity is bariatric surgery. Multiple cohort studies have demonstrated a consistent >30% decreased risk of cancer incidence in women, but not men, following bariatric surgery. However, the physiologic mechanisms driving obesity-associated cancer and the cancer-protective effect of bariatric surgery are not clearly defined. In this review, we highlight emerging concepts in the mechanistic understanding of obesity-associated cancer. Evidence from both human studies and preclinical animal models suggest that obesity drives carcinogenesis through dysregulation of systemic metabolism, immune dysfunction, and an altered gut microbiome. Additionally, we present related findings to suggest that bariatric surgery may disrupt and even reverse many of these mechanisms. Finally, we discuss the use of preclinical bariatric surgery animal models in the study of cancer biology. The prevention of cancer is emerging as an important indication for bariatric surgery. Elucidating the mechanisms through which bariatric surgery limits carcinogenesis is critical to developing a variety of interventions that intercept obesity-driven cancer.

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.

Hypoabsorptive surgeries cause limb-dependent changes in the gut endocannabinoidome and microbiome in association with beneficial metabolic effects

OBJECTIVE

To determine whether the metabolic benefits of hypoabsorptive surgeries are associated with changes in the gut endocannabinoidome (eCBome) and microbiome.

METHODS

Biliopancreatic diversion with duodenal switch (BPD-DS) and single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) were performed in diet-induced obese (DIO) male Wistar rats. Control groups fed a high-fat diet (HF) included sham-operated (SHAM HF) and SHAM HF-pair-weighed to BPD-DS (SHAM HF-PW). Body weight, fat mass gain, fecal energy loss, HOMA-IR, and gut-secreted hormone levels were measured. The levels of eCBome lipid mediators and prostaglandins were quantified in different intestinal segments by LC-MS/MS, while expression levels of genes encoding eCBome metabolic enzymes and receptors were determined by RT-qPCR. Metataxonomic (16S rRNA) analysis was performed on residual distal jejunum, proximal jejunum, and ileum contents.

RESULTS

BPD-DS and SADI-S reduced fat gain and HOMA-IR, while increasing glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) levels in HF-fed rats. Both surgeries induced potent limb-dependent alterations in eCBome mediators and in gut microbial ecology. In response to BPD-DS and SADI-S, changes in gut microbiota were significantly correlated with those of eCBome mediators. Principal component analyses revealed connections between PYY, N-oleoylethanolamine (OEA), N-linoleoylethanolamine (LEA), Clostridium, and Enterobacteriaceae_g_2 in the proximal and distal jejunum and in the ileum.

CONCLUSIONS

BPD-DS and SADI-S caused limb-dependent changes in the gut eCBome and microbiome. The present results indicate that these variables could significantly influence the beneficial metabolic outcome of hypoabsorptive bariatric surgeries.

Famsin, a novel gut-secreted hormone, contributes to metabolic adaptations to fasting via binding to its receptor OLFR796

The intestine is responsible for nutrient absorption and orchestrates metabolism in different organs during feeding, a process which is partly controlled by intestine-derived hormones. However, it is unclear whether the intestine plays an important role in metabolism during fasting. Here we have identified a novel hormone, famsin, which is secreted from the intestine and promotes metabolic adaptations to fasting. Mechanistically, famsin is shed from a single-pass transmembrane protein, Gm11437, during fasting and then binds OLFR796, an olfactory receptor, to activate intracellular calcium mobilization. This famsin-OLFR796 signaling axis promotes gluconeogenesis and ketogenesis for energy mobilization, and torpor for energy conservation during fasting. In addition, neutralization of famsin by an antibody improves blood glucose profiles in diabetic models, which identifies famsin as a potential therapeutic target for treating diabetes. Therefore, our results demonstrate that communication between the intestine and other organs by a famsin-OLFR796 signaling axis is critical for metabolic adaptations to fasting.

[Pharmacotherapy of obesity-Competition to bariatric surgery or a meaningful supplement?]

Obesity is a complex chronic disease and requires a long-term multimodal approach. The current treatment algorithm for treatment of obesity mainly consists of a stepwise approach, which starts with a lifestyle intervention followed by or combined with medication treatment, whereas bariatric surgery is often reserved for the last option. This article provides an overview of the currently available conservative medicinal treatment regimens and the currently approved medications as well as medications currently undergoing approval studies with respect to the efficacy and possible side effects. Special attention is paid to the importance of combination treatment of pharmacotherapy and surgery in the sense of a multimodal treatment. The data so far show that using a multimodal approach an improvement in the long-term weight loss and metabolic benefits can be achieved for the patients.

Molecular, Metabolic, and Nutritional Changes after Metabolic Surgery in Obese Diabetic Patients (MoMen): A Protocol for a Multicenter Prospective Cohort Study

Metabolic surgery is an essential option in the treatment of obese patients with type 2 diabetes (T2D). Despite its known advantages, this surgery still needs to be introduced in Malaysia. In this prospective study, the pathophysiological mechanisms at the molecular level will be studied and the metabolomics pathways of diabetes remission will be explored. The present study aims to evaluate the changes in the anthropometric measurements, body composition, phase angle, diet intake, biochemistry parameters, adipokines, microRNA, and metabolomics, both pre- and post-surgery, among obese diabetic patients in Malaysia. This is a multicenter prospective cohort study that will involve obese patients (n = 102) with a body mass index (BMI) of ≥25 kg/m2 (Asian BMI categories: WHO/IASO/IOTF, 2000) who will undergo metabolic surgery. They will be categorized into three groups: non-diabetes, prediabetes, and diabetes. Their body composition will be measured using a bioimpedance analyzer (BIA). The phase angle (PhA) data will be analyzed. Venous blood will be collected from each patient for glycated hemoglobin (HbA1c), lipids, liver, renal profile, hormones, adipokines, and molecular and metabolomics analyses. The serum microRNA will be measured. A gene expression study of the adipose tissue of different groups will be conducted to compare the groups. The relationship between the 1HNMR-metabolic fingerprint and the patients’ lifestyles and dietary practices will be determined. The factors responsible for the excellent remission of T2D will be explored in this study.

Exploration of fMRI brain responses to oral sucrose after Roux-en-Y gastric bypass in obese yucatan minipigs in relationship with microbiota and metabolomics profiles

BACKGROUND & AIMS

In most cases, Roux-en-Y gastric bypass (RYGBP) is an efficient intervention to lose weight, change eating behavior and improve metabolic outcomes in obese patients. We hypothesized that weight loss induced by RYGBP in obese Yucatan minipigs would induce specific modifications of the gut-brain axis and neurocognitive responses to oral sucrose stimulation in relationship with food intake control.

METHODS

An integrative study was performed after SHAM (n = 8) or RYGBP (n = 8) surgery to disentangle the physiological, metabolic and neurocognitive mechanisms of RYGBP. BOLD fMRI responses to sucrose stimulations at different concentrations, brain mRNA expression, cecal microbiota, and plasma metabolomics were explored 4 months after surgery and integrated with WGCNA analysis.

RESULTS

We showed that weight loss induced by RYGBP or SHAM modulated differently the frontostriatal responses to oral sucrose stimulation, suggesting a different hedonic treatment and inhibitory control related to palatable food after RYGBP. The expression of brain genes involved in the serotoninergic and cannabinoid systems were impacted by RYGBP. Cecal microbiota was deeply modified and many metabolite features were differentially increased in RYGBP. Data integration with WGCNA identified interactions between key drivers of OTUs and metabolites features linked to RYGBP.

CONCLUSION

This longitudinal study in the obese minipig model illustrates with a systemic and integrative analysis the mid-term consequences of RYGBP on brain mRNA expression, cecal microbiota and plasma metabolites. We confirmed the impact of RYGBP on functional brain responses related to food reward, hedonic evaluation and inhibitory control, which are key factors for the success of anti-obesity therapy and weight loss maintenance.

The implication of gut microbiota in recovery from gastrointestinal surgery

Recovery from gastrointestinal (GI) surgery is often interrupted by the unpredictable occurrence of postoperative complications, including infections, anastomotic leak, GI dysmotility, malabsorption, cancer development, and cancer recurrence, in which the implication of gut microbiota is beginning to emerge. Gut microbiota can be imbalanced before surgery due to the underlying disease and its treatment. The immediate preparations for GI surgery, including fasting, mechanical bowel cleaning, and antibiotic intervention, disrupt gut microbiota. Surgical removal of GI segments also perturbs gut microbiota due to GI tract reconstruction and epithelial barrier destruction. In return, the altered gut microbiota contributes to the occurrence of postoperative complications. Therefore, understanding how to balance the gut microbiota during the perioperative period is important for surgeons. We aim to overview the current knowledge to investigate the role of gut microbiota in recovery from GI surgery, focusing on the crosstalk between gut microbiota and host in the pathogenesis of postoperative complications. A comprehensive understanding of the postoperative response of the GI tract to the altered gut microbiota provides valuable cues for surgeons to preserve the beneficial functions and suppress the adverse effects of gut microbiota, which will help to enhance recovery from GI surgery.

Mechanisms linking bariatric surgery to adipose tissue, glucose metabolism, fatty liver disease and gut microbiota

PURPOSE

In the last 20 years, bariatric surgery has achieved an important role in translational and clinical research because of obesity comorbidities. Initially, a tool to lose weight, bariatric surgery now has been shown to be involved in several metabolic pathways.

METHODS

We conducted a narrative review discussing the underlying mechanisms that could explain the impact of bariatric surgery and the relationship between obesity and adipose tissue, T2D, gut microbiota, and NAFLD.

RESULTS

Bariatric surgery has an impact in the relation between obesity and type 2 diabetes, but in addition  it induces the white-to-brown adipocyte trans-differentiation, by enhancing thermogenesis. Another issue is the connection of bariatric surgery with the gut microbiota and its role in the complex mechanism underlying weight gain.

CONCLUSION

Bariatric surgery modifies gut microbiota, and these modifications influence lipid metabolism, leading to improvement of non-alcoholic fatty liver disease.

Mucosal and hormonal adaptations after Roux-en-Y gastric bypass

The aim of this study was to perform a comprehensive literature review regarding the relevant hormonal and histologic changes observed after Roux-en-Y gastric bypass (RYGB). We aimed to describe the relevant hormonal (glucagon-like peptides 1 and 2 [GLP-1 and GLP-2], peptide YY [PYY], oxyntomodulin [OXM], bile acids [BA], cholecystokinin [CCK], ghrelin, glucagon, gastric inhibitory polypeptide [GIP], and amylin) profiles, as well as the histologic (mucosal cellular) adaptations happening after patients undergo RYGB. Our review compiles the current evidence and furthers the understanding of the rationale behind the food intake regulatory adaptations occurring after RYGB surgery. We identify gaps in the literature where the potential for future investigations and therapeutics may lie. We performed a comprehensive database search without language restrictions looking for RYGB bariatric surgery outcomes in patients with pre- and postoperative blood work hormonal profiling and/or gut mucosal biopsies. We gathered the relevant study results and describe them in this review. Where human findings were lacking, we included animal model studies. The amalgamation of physiologic, metabolic, and cellular adaptations following RYGB is yet to be fully characterized. This constitutes a fundamental aspiration for enhancing and individualizing obesity therapy.

Bariatric Surgery Associates with Nonalcoholic Steatohepatitis/Hepatocellular Carcinoma Amelioration via SPP1 Suppression

Nonalcoholic steatohepatitis (NASH) is one of the most common chronic liver diseases worldwide and no effective drugs or treatments have been approved for disease management. Recently, bariatric surgery (BS) is considered to be a novel disease-modifying therapy for NASH and liver metabolic diseases, according to clinical follow-up studies. Despite the revealment of physiopathological alterations, underlying mechanisms and key factors remain indeterminate. This study included multiple bulk RNA-sequencing datasets to investigate transcriptome variation in one-year follow-up BS and diet management (Diet) NASH patients' liver biopsies. Liver functions, fibrosis, and carcinogenesis were predicted in liver samples via hallmark-based function enrichment analysis. Key factors generated from multi-dataset comparison were further assessed with hepatocellular carcinoma (HCC) progression and prognosis. BS leads to active gene expression alterations in NASH liver in comparison to diet management (Diet). Both approaches reduce cell stress and immune response, whereas BS contributes to higher metabolic levels and lower apoptosis levels. The macrophage infiltration, adipose accumulation, and fibroblast activation were revealed to be lower in post-BS NASH livers, further demonstrating positive correlations mutually. Seven key genes (MNDA, ALOX5AP, PECAM1, SPP1, CD86, FGF21, CSTA) were screened out as potential macrophage-associated and carcinogenetic factors suppressed by BS. SPP1 was identified as a crucial factor participating in BS intervened NASH-HCC progression. This study determined that BS exerts potentially superior protective functions in NASH livers compared to diet management. SPP1 may serve as a novel factor to study the functionalities of BS on NASH patients.

AlOtaibi A, Alshareef K, Alzahrani KM. Quality of Life and Body Mass Index Changes Three Years After Laparoscopic Sleeve Gastrectomy in Taif City, Saudi Arabia

Background Obesity has become a major global health challenge, and its prevalence has tripled in the last four decades. Impaired quality of life (QoL) is a strong incentive for severely obese patients to seek help. Sleeve gastrectomy (SG) is the most frequently practiced bariatric procedure worldwide. This study aimed to investigate the QoL and changes in body weight three years post laparoscopic SG. Methods A cross-sectional, observational study was performed in outpatient clinics in Taif city, Saudi Arabia. The study included 147 adult patients who underwent SG at least three years before inclusion in the study. Data were collected using a questionnaire designed based on the validated Bariatric quality of life (BQL) and Gastroesophageal Reflux Disease Health-Related Quality of Life (GERD-HRQoL) surveys. Results All patients were suffering from class I, class II, or class III obesity before undergoing SG. Three years post-surgery, 72.8% reached their normal weight or were overweight (P<0.001). The mean± SD BMI (45± 7.0 kg/m²) significantly decreased to 26.8± 4.6 kg/m² (P<0.001). Most of the participants (78.2%) achieved an excess weight loss percent (EWL%) of 75% or more. The mean± SD BQL score was 45.5± 5.2 points and the median (IQR) GERD-HRQoL score was 7 (15). Higher EWL% was significantly associated with a higher BQL score (P=0.041). Conclusions The current study revealed a better quality of life among patients experiencing higher rates of excess weight loss percent (EWL%) after three years of sleeve gastrectomy as compared to other patients.

Potential associations between alterations in gut microbiome and obesity-related traits after the bariatric surgery

AIM

This study aimed to examine the effects of both obesity and bariatric surgery on gut microbiome, dietary intake, as well as metabolic and inflammatory parameters.

METHODS

All participants (15 with morbid obesity who had bariatric surgery, 8 with morbid obesity and 11 non-obese) were followed-up for a 6-month period with the interviews at baseline (M0), at the end of 3 (M3) and 6 months (M6). Dietary assessment was done, and blood and faecal samples were collected.

RESULTS

Dietary energy and nutrient intakes as well as serum levels glucose, total cholesterol, LDL-cholesterol, and hs-CRP levels decreased by surgery (p<0.05, for each). Participants with morbid obesity had higher levels of Firmicutes and lower levels of Bacteroidetes at M0 compared to non-obese participants. The abundances of Bacteroidetes increased (p=0.02) while Firmicutes decreased (p>0.05) by the surgery, leading a significant decrease in Firmicutes/Bacteroidetes ratio (p=0.01). At sub-phylum level, the abundances of Lactobacillus and Bifidobacterium decreased while Akkermansia increased by the surgery (p<0.01, for each). Although participants who are morbidly obese had a distinct profile according to ß-diversity indices at M0, it became similar with the profile of non-obese participants (p>0.05) at M3 and M6. Similarly, α-diversity indices were lower in subjects with morbid obesity at M0, but became similar to levels in non-obese controls at M6.

CONCLUSION

This study confirmed that bariatric surgery has substantial impacts on gut microbiome composition and diversity, as well as anthropometrical measurements and biochemical parameters, which were associated with the alterations in dietary intake patterns. This article is protected by copyright. All rights reserved.

The Impact of Bariatric-Surgery-Induced Weight Loss on Patients Undergoing Liver Transplant: A Focus on Metabolism, Pathophysiological Changes, and Outcome in Obese Patients Suffering NAFLD-Related Cirrhosis

Because of their condition, patients with morbid obesity develop several histopathological changes in the liver, such as non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), cirrhosis, and end-stage liver disease (ESLD). Hence, a liver transplant (LT) becomes an opportune solution for them. Due to many challenges during the perioperative and postoperative periods, these patients are recommended to lose weight before the surgery. There are many proposals to achieve this goal, such as intragastric balloons and many different bariatric surgery (BS) procedures in combination with a preparation diet (very-low-calorie diet, ketogenic diet, etc.). All the interventions focus on losing weight and keeping the continuity and functionality of the digestive tract to avoid postoperative complications. Thus, this review analyzes recent publications regarding the metabolic and pathophysiological impacts of BS in LT patients suffering from NAFLD-related cirrhosis, the effect of weight loss on postoperative complications, and exposes the cost-effectiveness of performing BS before, after, and at liver transplantation. Finally, the authors recommend BS before the LT since there are many positive effects and better outcomes for patients who lose weight before the procedure. Nevertheless, further multicentric studies are needed to determine the generalizability of these recommendations due to their impact on public health.

Comparative Effectiveness and Safety Between Endoscopic Sleeve Gastroplasty and Laparoscopic Sleeve Gastrectomy: a Meta-analysis of 6775 Individuals with Obesity

INTRODUCTION

Endoscopic sleeve gastroplasty (ESG) is a novel endoscopic bariatric therapy that complements current medical and surgical therapeutic offerings for weight management and fills an unmet need. Few meta-analyses compared ESG to laparoscopic sleeve gastrectomy (LSG). However, these studies relied on indirect evidence derived from non-comparative studies. Comparative effectiveness data derived from direct comparative studies is needed. We performed a meta-analysis of studies that directly compared ESG with LSG.

METHODS

A comprehensive search of PubMed, Embase, and Cochrane databases was conducted. Single-arm studies were excluded. Pooled mean difference (MD) and risk ratio (RR) with 95% confidence intervals (CIs) were obtained within a random-effect model.

RESULTS

Seven studies with 6,775 patients (3,413 with ESG vs. 3,362 with LSG) were included. There were significant differences in 6-month (MD - 7.48; 95% CI - 10.44, - 4.52; P < 0.00001), 12-month (MD - 9.90; 95% CI - 10.59, - 9.22; P < 0.00001), and 24-month (MD - 7.63; 95% CI - 11.31, - 3.94; P < 0.0001) TBWL% favoring LSG over ESG. There was a trend toward lower incidence of adverse events with ESG compared to LSG but did not reach statistical significance (RR 0.51, 95% CI 0.23-1.11, P = 0.09). The incidence of new-onset gastroesophageal reflux disease (GERD) was significantly lower after ESG compared to LSG, 1.3% vs. 17.9%, respectively (RR 0.10, 95% CI 0.02-0.53, P = 0.006).

CONCLUSIONS

ESG achieved clinically adequate but lower short- and mid-term weight loss when compared to LSG, with fewer adverse events, including GERD. Given the stomach-sparing nature of ESG and acceptable safety profile, it provides an acceptable alternative to LSG for patients with mild-to-moderate obesity.

The role of obesity and bariatric surgery-induced weight loss in breast cancer

Obesity is a complex metabolic condition considered a worldwide public health crisis, and a deeper mechanistic understanding of obesity-associated diseases is urgently needed. Obesity comorbidities include many associated cancers and are estimated to account for 20% of female cancer deaths in the USA. Breast cancer, in particular, is associated with obesity and is the focus of this review. The exact causal links between obesity and breast cancer remain unclear. Still, interactions have emerged between body mass index, tumor molecular subtype, genetic background, and environmental factors that strongly suggest obesity influences the risk and progression of certain breast cancers. Supportive preclinical research uses various diet-induced obesity models to demonstrate that weight loss, via dietary interventions or changes in energy expenditure, reduces the onset or progression of breast cancers. Ongoing and future studies are now aimed at elucidating the underpinning mechanisms behind weight-loss-driven observations to improve therapy and outcomes in patients with breast cancer and reduce risk. This review aims to summarize the rapidly emerging literature on obesity and weight loss strategies with a focused discussion of bariatric surgery in both clinical and preclinical studies detailing the complex interactions between metabolism, immune response, and immunotherapy in the setting of obesity and breast cancer.

Obesity Management in the Primary Prevention of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most frequent primary hepatic malignancy and a leading cause of cancer-related death globally. HCC is associated with an indolent clinical presentation, resulting in frequent advanced stage diagnoses where surgical resection or transplant therapies are not an option and medical therapies are largely ineffective at improving survival. As such, there is a critical need to identify and enhance primary prevention strategies to mitigate HCC-related morbidity and mortality. Obesity is an independent risk factor for the onset and progression of HCC. Furthermore, obesity is a leading cause of nonalcoholic steatohepatitis (NASH), the fasting growing etiological factor of HCC. Herein, we review evolving clinical and mechanistic associations between obesity and hepatocarcinogenesis with an emphasis on the therapeutic efficacy of prevailing lifestyle/behavioral, medical, and surgical treatment strategies for weight reduction and NASH reversal.

Association of Bariatric Surgery With Cancer Risk and Mortality in Adults With Obesity

IMPORTANCE

Obesity increases the incidence and mortality from some types of cancer, but it remains uncertain whether intentional weight loss can decrease this risk.

OBJECTIVE

To investigate whether bariatric surgery is associated with lower cancer risk and mortality in patients with obesity.

DESIGN, SETTING, AND PARTICIPANTS

In the SPLENDID (Surgical Procedures and Long-term Effectiveness in Neoplastic Disease Incidence and Death) matched cohort study, adult patients with a body mass index of 35 or greater who underwent bariatric surgery at a US health system between 2004 and 2017 were included. Patients who underwent bariatric surgery were matched 1:5 to patients who did not undergo surgery for their obesity, resulting in a total of 30 318 patients. Follow-up ended in February 2021.

EXPOSURES

Bariatric surgery (n = 5053), including Roux-en-Y gastric bypass and sleeve gastrectomy, vs nonsurgical care (n = 25 265).

MAIN OUTCOMES AND MEASURES

Multivariable Cox regression analysis estimated time to incident obesity-associated cancer (a composite of 13 cancer types as the primary end point) and cancer-related mortality.

RESULTS

The study included 30 318 patients (median age, 46 years; median body mass index, 45; 77% female; and 73% White) with a median follow-up of 6.1 years (IQR, 3.8-8.9 years). The mean between-group difference in body weight at 10 years was 24.8 kg (95% CI, 24.6-25.1 kg) or a 19.2% (95% CI, 19.1%-19.4%) greater weight loss in the bariatric surgery group. During follow-up, 96 patients in the bariatric surgery group and 780 patients in the nonsurgical control group had an incident obesity-associated cancer (incidence rate of 3.0 events vs 4.6 events, respectively, per 1000 person-years). The cumulative incidence of the primary end point at 10 years was 2.9% (95% CI, 2.2%-3.6%) in the bariatric surgery group and 4.9% (95% CI, 4.5%-5.3%) in the nonsurgical control group (absolute risk difference, 2.0% [95% CI, 1.2%-2.7%]; adjusted hazard ratio, 0.68 [95% CI, 0.53-0.87], P = .002). Cancer-related mortality occurred in 21 patients in the bariatric surgery group and 205 patients in the nonsurgical control group (incidence rate of 0.6 events vs 1.2 events, respectively, per 1000 person-years). The cumulative incidence of cancer-related mortality at 10 years was 0.8% (95% CI, 0.4%-1.2%) in the bariatric surgery group and 1.4% (95% CI, 1.1%-1.6%) in the nonsurgical control group (absolute risk difference, 0.6% [95% CI, 0.1%-1.0%]; adjusted hazard ratio, 0.52 [95% CI, 0.31-0.88], P = .01).

CONCLUSIONS AND RELEVANCE

Among adults with obesity, bariatric surgery compared with no surgery was associated with a significantly lower incidence of obesity-associated cancer and cancer-related mortality.

Changes in appetite, taste, smell, and food aversion in post-bariatric patients and their relations with surgery time, weight loss and regain

PURPOSE

We aimed to study the occurrence of long-term changes in appetite, taste, smell perceptions, and food aversion in patients following bariatric surgery. Additionally, we compared two surgery types, excess weight loss, rate of weight regain, and time since surgery.

METHODS

This cross-sectional study included 146 post-bariatric patients who were without regular medical follow-up (126 post-Roux-en-Y gastric bypass [RYGB] and 20 post-sleeve gastrectomy [SG]), aged 42 ± 8 years, BMI of 32.6 ± 6.3 kg/m², with excess weight loss of 87.5 ± 20.2%, rate of weight regain (RWR) of 15.4 [3.9-30.9]% and time since surgery of 5.0 ± 4.0 years. They answered a questionnaire about sensory and food perceptions at their first medical appointment at our unit.

RESULTS

Changes in appetite (76%), taste (48.6%), and an increased sensation for sweet taste (60.2%) frequently occurred in our sample. Sensory and food aversion perceptions, taste changes to specific foods, and loss level of taste and smell were similar between RYGB and SG. No differences between patients with or without changes in appetite, taste, smell, and food aversion perceptions concerning excess weight loss were observed. The RWR in post-RYGB was lower in those with changes in taste and smell (P = 0.05). Sensory changes were noted in those with shorter time since surgery for both surgeries (P ≤ 0.05).

CONCLUSION

Changes in appetite and taste occurred frequently in our patients even in the long term. Post-RYGB patients with lower RWR had more changes in taste and smell while a shorter time since surgery showed more frequent changes in appetite, taste, and smell.

LEVEL OF EVIDENCE

Level V, cross-sectional study.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT04193384).

When fat meets the gut-focus on intestinal lipid handling in metabolic health and disease

The regular overconsumption of energy‐dense foods (rich in lipids and sugars) results in elevated intestinal nutrient absorption and consequently excessive accumulation of lipids in the liver, adipose tissue, skeletal muscles, and other organs. This can eventually lead to obesity and obesity‐associated diseases such as type 2 diabetes (T2D), non‐alcoholic fatty liver disease (NAFLD), cardiovascular disease, and certain types of cancer, as well as aggravate inflammatory bowel disease (IBD). Therefore, targeting the pathways that regulate intestinal nutrient absorption holds significant therapeutic potential. In this review, we discuss the molecular and cellular mechanisms controlling intestinal lipid handling, their relevance to the development of metabolic diseases, and emerging therapeutic strategies.

Vertical sleeve gastrectomy increases duodenal Lactobacillus spp. richness associated with the activation of intestinal HIF2α signaling and metabolic benefits

OBJECTIVE

Vertical Sleeve Gastrectomy (VSG) is one of the most efficacious treatments for obesity and its comorbidities. Although a range of evidence suggests that alterations of the microbiota in the distal gut following VSG are pivotal to these metabolic improvements, the effect of surgery to alter the microbiota of the proximal intestine and its effect on host physiology remain largely unknown. As the main bacteria in the upper small intestine, Lactobacillus subspecies have been appreciated as important regulators of gut function. These bacteria also regulate intestinal Hypoxia- Inducible Factor 2α (HIF2α) signaling that plays an integral role in gut physiology and iron absorption. In the present study, we sought to determine the impact of VSG on Lactobacillus spp. in the small intestine and potential downstream impacts of Lactobacillus spp. on HIF2α, specifically in the duodenum.

METHODS

To determine the effects of VSG on the microbiota and HIF2α signaling in the duodenum, VSG surgeries were performed on diet-induced obese mice. To further probe the relationship between Lactobacillus spp. and HIF2α signaling in the duodenum, we applied a customized high-fat but iron-deficient diet on mice to increase duodenal HIF2α signaling and determined alterations of gut bacteria. To explore the causal role of Lactobacillus spp. in duodenal HIF2α signaling activation, we chronically administered probiotics containing Lactobacillus spp. to high-fat-fed obese mice. Lastly, we studied the effect of lactate, the major metabolite of Lactobacilli, on HIF2α in ex vivo duodenal organoids.

RESULTS

There were pronounced increases in the abundance of Lactobacillus spp. in samples isolated from duodenal epithelium in VSG-operated mice as compared to sham-operated mice. This was accompanied by an increase in the expression of genes that are targets of HIF2α in the duodenum of VSG-treated mice. Activating HIF2α signaling with a high-fat but iron-deficient diet resulted in weight loss, improvements in glucose regulation, and increased Lactobacillus spp. richness in the duodenum as compared to mice on an iron-replete diet. Chronic administration of probiotics containing Lactobacillus spp. not only increased HIF2α signaling in the duodenum such as occurs after VSG but also resulted in reduced weight gain and improved glucose tolerance in high-fat-fed mice. Furthermore, lactate was able to activate HIF2α in ex vivo duodenal organoids.

CONCLUSIONS

These results support a model whereby VSG increases duodenal Lactobacillus richness and potentially stimulates intestinal HIF2α signaling via increased lactate production.

Consistent gut bacterial and short-chain fatty acid signatures in hypoabsorptive bariatric surgeries correlate with metabolic benefits in rats

OBJECTIVE

The study aimed at comparing how changes in the gut microbiota are associated to the beneficial effects of the most clinically efficient hypoabsorptive bariatric procedures, namely Roux-en-Y gastric bypass (RYGB), biliopancreatic diversion with duodenal switch (BPD-DS) and single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S).

METHODS

Diet-induced obese (DIO) male Wistar rats were divided into seven groups. In addition to the groups subjected to RYGB, BPD-DS and SADI-S, the following four control groups were included: SHAM-operated rats fed a high-fat diet (SHAM HF), SHAM fed a low-fat diet (SHAM LF), SHAM HF-pair-weighed to BPD-DS (SHAM HF-PW) and sleeve-gastrectomy (SG) rats. Body weight, food intake, glucose tolerance, insulin sensitivity/resistance, and L-cell secretion were assessed. The gut microbiota (16 S ribosomal RNA gene sequencing) as well as the fecal and cæcal contents of short-chain fatty acids (SCFAs) were also analyzed prior to, and after the surgeries.

RESULTS

The present study demonstrates the beneficial effect of RYGB, BPD-DS and SADI-S on fat mass gain and glucose metabolism in DIO rats. These benefits were proportional to the effect of the surgeries on food digestibility (BPD-DS > SADI-S > RYGB). Notably, hypoabsorptive surgeries led to consonant microbial signatures characterized by decreased abundance of the Ruminococcaceae (Oscillospira and Ruminococcus), Oscillospiraceae (Oscillibacter) and Christensenellaceae, and increased abundance of the Clostridiaceae (Clostridium), Sutterellaceae (Sutterella) and Enterobacteriaceae. The gut bacteria following hypoabsorptive surgeries were associated with higher fecal levels of propionate, butyrate, isobutyrate and isovalerate. Increases in the fecal SCFAs were in turn positively and strongly correlated with the levels of peptide tyrosine-tyrosine (PYY) and with the beneficial effects of the surgery.

CONCLUSION

The present study emphasizes the consistency with which the three major hypoabsorptive bariatric procedures RYGB, BPD-DS and SADI-S create a gut microbial environment capable of producing a SCFA profile favorable to the secretion of PYY and to beneficial metabolic effects.

Sleeve gastrectomy improves lipid dysmetabolism by downregulating the USP20-HSPA2 axis in diet-induced obese mice

INTRODUCTION

Obesity is a metabolic disease accompanied by abnormalities in lipid metabolism that can cause hyperlipidemia, non-alcoholic fatty liver disease, and artery atherosclerosis. Sleeve gastrectomy (SG) is a type of bariatric surgery that can effectively treat obesity and improve lipid metabolism. However, its specific underlying mechanism remains elusive.

METHODS

We performed SG, and sham surgery on two groups of diet-induced obese mice. Histology and lipid analysis were used to evaluate operation effect. Immunohistochemistry, immunoblotting, real-time quantitative PCR, immunoprecipitation, immunofluorescence and mass spectrometry were used to reveal the potential mechanisms of SG.

RESULTS

Compared to the sham group, the SG group displayed a downregulation of deubiquitinase ubiquitin-specific peptidase 20 (USP20). Moreover, USP20 could promote lipid accumulation in vitro. Co-immunoprecipitation and mass spectrometry analyses showed that heat-shock protein family A member 2 (HSPA2) potentially acts as a substrate of USP20. HSPA2 was also downregulated in the SG group and could promote lipid accumulation in vitro. Further research showed that USP20 targeted and stabilized HSPA2 via the ubiquitin-proteasome pathway.

CONCLUSION

The downregulation of the USP20-HSPA2 axis in diet-induced obese mice following SG improved lipid dysmetabolism, indicating that USP20-HSPA2 axis was a noninvasive therapeutic target to be investigated in the future.

First Inventory of Access and Quality of Metabolic Surgery Across Europe

INTRODUCTION

Europe consists of 51 independent countries. Variation in healthcare regulations results in differing challenges faced by patients and professionals. This study aimed to gain more insight into the accessibility, patient pathway and quality indicators of metabolic and body contouring surgery.

METHODS AND MATERIALS

Expert representatives in the metabolic field from all 51 countries were sent an electronic self-administered online questionnaire on their data and experiences from the previous year exploring accessibility to and quality indicators for metabolic surgery and plastic surgery after weight loss.

RESULTS

Forty-five responses were collected. Sixty-eight percent of countries had eligibility criteria for metabolic surgery; 59% adhered to the guidelines. Forty-six percent had reimbursement criteria for metabolic surgery. Forty-one percent had eligibility criteria for plastic surgery and 31% reimbursement criteria. Average tariffs for a metabolic procedure varied € 800 to 16,000. MDTs were mandated in 78%, with team members varying significantly. Referral practices differed. In 45%, metabolic surgery is performed by pure metabolic surgeons, whilst re-operations were performed by a metabolic surgeon in 28%. A metabolic training programme was available in 23%. Access to metabolic surgery was rated poor to very poor in 33%. Thirty-five percent had a bariatric registry. Procedure numbers and numbers of hospitals performing metabolic surgery varied significantly. Twenty-four percent of countries required a minimum procedure number for metabolic centres, which varied from 25 to 200 procedures.

CONCLUSION

There are myriad differences between European countries in terms of accessibility to and quality indicators of metabolic surgery. Lack of funding, education and structure fuels this disparity. Criteria should be standardised across Europe with clear guidelines.

Bariatric surgery and the liver-Mechanisms, benefits, and risks

The prevalence of obesity and metabolic diseases such as type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) has risen dramatically over the past decades. At present, bariatric surgery is the most effective treatment for this global health problem, through effects on food intake, gut hormone secretion, metabolic signaling pathways, and adipose tissue dysfunction. The liver occupies a central role in carbohydrate, protein, and lipid metabolism. Notably, a reduction in hepatic fat content and an improvement in hepatic insulin resistance are among the earliest beneficial effects of bariatric surgery, which has therefore emerged as an attractive treatment option for NAFLD. However, as the scope and popularity of weight loss surgery have expanded, new questions have arisen regarding its safety in patients with liver cirrhosis, the outcome of liver transplantation in patients with a history of bariatric surgery, and over incidental reports of liver failure following surgery. Studies in humans and rodents have also linked bariatric surgery to an increased risk of developing alcohol use disorder, a major risk factor for liver disease. This review integrates data from clinical and translational research to delineate both the beneficial impact of bariatric surgery on the liver and the potential risks involved.

Reversal of Functional Brain Activity Related to Gut Microbiome and Hormones After VSG Surgery in Patients With Obesity

CONTEXT

Vertical sleeve gastrectomy (VSG) is becoming a prioritized surgical intervention for obese individuals; however, the brain circuits that mediate its effective control of food intake and predict surgical outcome remain largely unclear.

OBJECTIVE

We investigated VSG-correlated alterations of the gut-brain axis.

METHODS

In this observational cohort study, 80 patients with obesity were screened. A total of 36 patients together with 26 normal-weight subjects were enrolled and evaluated using the 21-item Three-Factor Eating Questionnaire (TFEQ), MRI scanning, plasma intestinal hormone analysis, and fecal sample sequencing. Thirty-two patients underwent VSG treatment and 19 subjects completed an average of 4-month follow-up evaluation. Data-driven regional homogeneity (ReHo) coupled with seed-based connectivity analysis were used to quantify VSG-related brain activity. Longitudinal alterations of body weight, eating behavior, brain activity, gastrointestinal hormones, and gut microbiota were detected and subjected to repeated measures correlation analysis.

RESULTS

VSG induced significant functional changes in the right putamen (PUT.R) and left supplementary motor area, both of which correlated with weight loss and TFEQ scores. Moreover, postprandial levels of active glucagon-like peptide-1 (aGLP-1) and Ghrelin were associated with ReHo of PUT.R; meanwhile, relative abundance of Clostridia increased by VSG was associated with improvements in aGLP-1 secretion, PUT.R activity, and weight loss. Importantly, VSG normalized excessive functional connectivities with PUT.R, among which baseline connectivity between PUT.R and right orbitofrontal cortex was related to postoperative weight loss.

CONCLUSION

VSG causes correlated alterations of gut-brain axis, including Clostridia, postprandial aGLP-1, PUT.R activity, and eating habits. Preoperative connectivity of PUT.R may represent a potential predictive marker of surgical outcome in patients with obesity.

Obesity and Cancer: the Profile of a Population who Underwent Bariatric Surgery

INTRODUCTION

Obesity is a significant risk factor for cancer incidence and mortality. The number of patients with obesity who undergo bariatric surgery is increasing; however, the impact of such a procedure in affecting the risk of cancer is not completely understood yet.

METHODS

We conducted a retrospective unicentric cohort study to characterize the occurrence of cancer in patients who underwent bariatric surgery from January 2010 to December 2018. For cases of cancer identified after bariatric surgery, we performed a cancer-free survival analysis over time. We also performed a cross-sectional analysis of demographic and clinical characteristics at the time of surgery and compared patients with or without a cancer diagnosis.

RESULTS

Of the 2578 patients who underwent bariatric surgery, 117 patients (4.5%) were diagnosed with a cancer. Fifty-nine cases were diagnosed before surgery, and the remaining 58 cases occurred after the bariatric procedure. The prevalence of cancer was more accentuated in women (4.9%) than among men (2.7%). Thyroid and breast cancer were the most frequent before and after bariatric surgery, respectively. On average, patients with cancer diagnosis were older (49.0 vs 43.3 years, p<0.001) and with a lower level of education (7.4 vs 8.6 school years, p=0.002).

CONCLUSION

Almost all the cases of cancer identified in this study were obesity-related cancers. Further prospective studies are needed to extend the current knowledge regarding the cancer risk profile of patients who undergo bariatric surgery.

Effect of Roux-en-Y gastric bypass on the pharmacokinetic-pharmacodynamic relationships of liquid and controlled-release formulations of oxycodone

The physiological changes following Roux-en-Y gastric bypass (RYGB) surgery may impact drug release from mechanistically different controlled-release tablets, making generic substitution inappropriate. This study aimed to characterise the pharmacokinetic-pharmacodynamic relationships of oxycodone from a lipid-based and water-swellable controlled-release tablet in RYGB patients. Twenty RYGB patients received 10-mg oral solution oxycodone or 20-mg controlled-release (water-swellable or lipid-based) oxycodone in a three-way, randomised, semiblinded and cross-over study. Blood sampling and pupillary recordings were conducted over a 24-h period. A previously established pharmacokinetic-pharmacodynamic model of these three formulations in healthy volunteers was used in the analysis as a reference model. No differences in absorption kinetics were seen between controlled-release formulations in patients. However, the absorption lag time was 11.5 min in patients vs 14 min in healthy volunteers for controlled-release tablets (P < 0.001). Furthermore, oral bioavailability was 14.4% higher in patients compared to healthy volunteers regardless of formulation type (P < 0.001). Oxycodone pharmacodynamics were not significantly affected by formulation or patient status. However, baseline pupil diameter was inversely correlated with age (P < 0.001) and plasma concentrations of oxycodone at half-maximum effect were 31% lower in males compared to females (P < 0.05). Generic substitution of monophasic lipid-based and water-swellable controlled-release oxycodone tablets may be considered safe in RYGB patients.

Obesity, Cancer, and Risk Reduction with Bariatric Surgery

The prevalence of noncommunicable diseases has increased dramatically in North America and throughout the world and is expected to continue increasing in coming years. Obesity has been linked to several types of cancers and is associated with increased morbidity and mortality following cancer diagnosis. Bariatric surgery has emerged as the prominent model to evaluate the effects of intentional weight loss on cancer incidence and outcomes. Current literature, comprising prospective cohort investigations, indicates site-specific reductions in cancer risk with select bariatric procedures. Future research is required to establish evidence-based indications for bariatric surgery in the context of cancer prevention.

Bariatric surgery stirs symbionts to counteract diabesity by CA(7)Sting a liver-generated bile acid into the mix

Obesity and diabetes are major health challenges for the 21^st century. Effective treatments affect nutrient signaling along the gut microbiome-bile acid axis. In this issue of Cell, Chaudhari et al. demonstrate that a gut microbial secondary bile acid stimulates hepatic synthesis of a sulfated bile acid with anti-diabetic properties.

Ghrelin and Glucagon-Like Peptide-1: A Gut-Brain Axis Battle for Food Reward

Eating behaviors are influenced by the reinforcing properties of foods that can favor decisions driven by reward incentives over metabolic needs. These food reward-motivated behaviors are modulated by gut-derived peptides such as ghrelin and glucagon-like peptide-1 (GLP-1) that are well-established to promote or reduce energy intake, respectively. In this review we highlight the antagonizing actions of ghrelin and GLP-1 on various behavioral constructs related to food reward/reinforcement, including reactivity to food cues, conditioned meal anticipation, effort-based food-motivated behaviors, and flavor-nutrient preference and aversion learning. We integrate physiological and behavioral neuroscience studies conducted in both rodents and human to illustrate translational findings of interest for the treatment of obesity or metabolic impairments. Collectively, the literature discussed herein highlights a model where ghrelin and GLP-1 regulate food reward-motivated behaviors via both competing and independent neurobiological and behavioral mechanisms.

Adaptations in gastrointestinal physiology after sleeve gastrectomy and Roux-en-Y gastric bypass

Linked to the growing obesity epidemic, demand for bariatric and metabolic surgery has increased, the most common procedures being sleeve gastrectomy and Roux-en-Y gastric bypass. Originally, bariatric procedures were described as purely restrictive, malabsorptive, or combined restrictive-malabsorptive procedures limiting food intake, nutrient absorption, or both. Nowadays, anatomical alterations are known to affect gastrointestinal physiology, which in turn affects the digestion and absorption of nutrients and drugs. Therefore, understanding gastrointestinal physiology is crucial to prevent postoperative nutritional deficiencies and to optimise postoperative drug therapy. Preclinical and clinical research indicates that sleeve gastrectomy accelerates liquid and solid gastric emptying and small intestinal transit, and increases bile acid serum levels, whereas its effects on gastrointestinal acidity, gastric and pancreatic secretions, surface area, and colonic transit remain largely unknown. Roux-en-Y gastric bypass diminishes gastric acid secretion, accelerates liquid gastric emptying, and increases bile acid serum levels, but its effects on intestinal pH, solid gastric emptying, intestinal transit time, gastric enzyme secretions, and surface area remain largely unknown. In this Review, we summarise current knowledge of the effects of these two procedures on gastrointestinal physiology and assess the knowledge gaps.

The Phantom Satiation Hypothesis of Bariatric Surgery

The excitation of vagal mechanoreceptors located in the stomach wall directly contributes to satiation. Thus, a loss of gastric innervation would normally be expected to result in abrogated satiation, hyperphagia, and unwanted weight gain. While Roux-en-Y-gastric bypass (RYGB) inevitably results in gastric denervation, paradoxically, bypassed subjects continue to experience satiation. Inspired by the literature in neurology on phantom limbs, I propose a new hypothesis in which damage to the stomach innervation during RYGB, including its vagal supply, leads to large-scale maladaptive changes in viscerosensory nerves and connected brain circuits. As a result, satiation may continue to arise, sometimes at exaggerated levels, even in subjects with a denervated or truncated stomach. The same maladaptive changes may also contribute to dysautonomia, unexplained pain, and new emotional responses to eating. I further revisit the metabolic benefits of bariatric surgery, with an emphasis on RYGB, in the light of this phantom satiation hypothesis.

The effects of adolescent laparoscopic adjustable gastric band and sleeve gastrectomy on markers of bone health and bone turnover

25-hydroxy vitamin D (25 OHD) deficiency and secondary hyperparathyroidism have been seen after metabolic and bariatric surgery, but data are lacking on the bone health outcomes of adolescent sleeve gastrectomy (SG). The purpose of this study was to examine bone-related nutrition after SG, compared to laparoscopic adjustable gastric band (LAGB), and trend bone turnover markers following SG. This is an observational study of 197 adolescents who underwent LAGB (n = 98) or SG (n = 99). Bone health labs were collected at baseline and 6 and/or 12 months after LAGB or SG, with additional analysis of bone turnover markers in the SG group. Calcium and 25 OHD levels increased at 6 and 12 months after LAGB and SG, with no difference between the surgeries. Parathyroid hormone levels decreased only in the SG group. SG patients had increased osteocalcin and carboxy-terminal cross-linking telopeptide of type 1 collagen (CTX) at 6 and 12 months post-SG, although CTX decreased between 6 and 12 months. Excess weight loss at 6 months predicted the rise in CTX, but the changes in osteocalcin and CTX could not be attributed to 25 OHD deficiency, hypocalcemia or hyperparathyroidism. Patients had improved 25 OHD levels post-surgery, which may be secondary to stringent vitamin supplementation guidelines. However, there were marked increases in bone turnover markers following SG. More studies are needed to evaluate the effects of SG on adolescent bone health and to correlate the early changes in bone turnover with bone mineral density and fracture risk.

Modifications of IGF2 and EGFR plasma protein concentrations in NAFLD patients after bariatric surgery

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is strictly associated with the epidemic of obesity and is becoming the most prevalent liver disease worldwide. In severe obesity, bariatric surgery (BS) is the most effective treatment not only for obesity but also for the associated metabolic co-morbidities, NAFLD, among others. To date, noninvasive diagnostic/prognostic methods cannot evaluate hepatic improvements following surgery.

OBJECTIVES

We aimed to measure plasma level of insulin-growth factor-2 protein (IGF2) and epithermal growth factor receptor (EGFR), and to assess their relationship with clinical and biochemical parameters during the 12 months follow-up.

METHODS

Demographic, clinical-biochemical data, and plasma IGF2 and EGFR were measured in 69 patients preoperatively (T0) and 6 and 12 months (T6M and T12M, respectively) after BS. Liver biopsy was performed at T0. Relationships between IGF2, EGFR, and several biochemical parameters were performed using Pearson or Spearman correlation analysis.

RESULTS

IGF2 plasma level increases during follow-up, passing from 2.5 (1.8-15.5) at baseline to 13.3 (8.6-19.1) at T12M, p < 0.001. Conversely, EGFR showed a not significant reduction. At T12M, the plasma level of both markers was comparable to those of lean subjects. The clinical-biochemical parameters (BMI, glycated hemoglobin, HOMA-IR) also return to the normal range at T12M. Correlation analysis demonstrated that IGF2 was significantly associated with total bilirubin, direct bilirubin, and albumin at T0 while with blood glucose, ALT, GGT, and AST/ALT ratio at T6M and T12M.

CONCLUSIONS

IGF2 plasma levels increase after bariatric surgery, and these changes are associated with the modification of hepatic biochemical parameters, even if other clinic or metabolic improvements cannot be excluded.

Recent advances in the mechanisms underlying the beneficial effects of bariatric and metabolic surgery

Bariatric and metabolic surgery (BMS) is the most effective treatment for obesity, type 2 diabetes and co-morbidities, including nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. The beneficial effects of BMS are beyond the primary goal of gastric restriction and nutrients malabsorption. Roux-en-Y gastric bypass and vertical sleeve gastrectomy are the 2 most commonly performed procedures of BMS. Both surgeries lead to physiologic changes in gastrointestinal tract; subsequently alter bile acids pool and composition, gut microbial activities, gut hormones, and circulating exosomes; and ultimately contribute to the improved glycemic control, insulin sensitivity, lipid metabolism, energy expenditure, and weight loss. The mechanisms underlying the benefits of BMS likely involve the bile acid-signaling pathway mediated mainly by nuclear farnesoid X receptor and the membrane Takeda G protein-coupled receptor, bile acids-gut microbiota interaction, and exosomes. In this review, we focus on recent advances in potential mechanisms and aim to learn novel insights into the molecular mechanisms underlying metabolic disorders.