A governmental program to encourage medical students to deliver primary prevention: experiment and evaluation in a French faculty of medicine.

BACKGROUND: A public health student service was set up by the French government in 2018 with the aim of increasing awareness of primary health promotion among the 47,000 students of medicine and other health professions. It is an annual program involving community-based actions on nutrition, physical activity, addiction or sexuality. Our objective was to evaluate its implementation at local level and the different experiences of the stakeholders. METHODS: A quasi-experimental study using process evaluation was performed in a Faculty of Medicine in Paris. Quantitative and qualitative data were collected from medical students who carried out preventive health actions, in the institutions in which the actions took place and from a subsample of beneficiaries. RESULTS: One hundred and eight actions were carried out by 341 students in 23 educational or social institutions, mostly high schools (n = 12, 52%). Two thirds of the students did not feel sufficiently prepared to deliver preventive health interventions (65.7%, 224/341); however the beneficiaries found that the interventions were good (278/280, 99,2%). Nineteen (83%) of the host institutions agreed to welcome health service students again, of which 9 required some modifications. For students, the reporting of a satisfactory health service experience was associated with the reporting of skills or knowledge acquisition (p < 0.01). Delivering actions in high schools and to a medium-sized number of beneficiaries per week was associated with students' satisfaction. No effect of gender or theme of prevention was observed. For 248/341 (72.7%) students, the public health service program prompts them to address prevention issues in the future. CONCLUSION: The public health service undertaken by medical students through the program is a feasible and acceptable means of delivering preventive actions. Reinforcement of training and closer interaction with the host institutions would improve results.

Senescence Alters PPARγ (Peroxisome Proliferator-Activated Receptor Gamma)-Dependent Fatty Acid Handling in Human Adipose Tissue Microvascular Endothelial Cells and Favors Inflammation.

OBJECTIVE: Adipose tissue (AT) dysfunction associated with obesity or aging is a major cause for lipid redistribution and the progression of cardiometabolic disorders. Our goal is to decipher the contribution of human AT microvascular endothelial cells (ECs) in the maintenance of fatty acid (FA) fluxes and the impact of senescence on their function. APPROACH AND RESULTS: We used freshly isolated primary microvascular ECs from human AT. Our data identified the endothelial FA handling machinery including FATPs (FA transport proteins) FATP1, FATP3, FATP4, and CD36 as well as FABP4 (FA binding protein 4). We showed that PPARγ (peroxisome proliferator-activated receptor gamma) regulates the expression of FATP1, CD36, and FABP4 and is a major regulator of FA uptake in human AT EC (hATEC). We provided evidence that endothelial PPARγ activity is modulated by senescence. Indeed, the positive regulation of FA transport by PPARγ agonist was abolished, whereas the emergence of an inflammatory response was favored in senescent hATEC. This was associated with the retention of nuclear FOXO1 (forkhead box protein O1), whereas nuclear PPARγ translocation was impaired. CONCLUSIONS: These data support the notion that PPARγ is a key regulator of primary hATEC function including FA handling and inflammatory response. However, the outcome of PPARγ activation is modulated by senescence, a phenomenon that may impact the ability of hATEC to properly respond to and handle lipid fluxes. Finally, our work highlights the role of hATEC in the regulation of FA fluxes and reveals that dysfunction of these cells with accelerated aging is likely to participate to AT dysfunction and the redistribution of lipids.

CD36 Is a Marker of Human Adipocyte Progenitors with Pronounced Adipogenic and Triglyceride Accumulation Potential.

White adipose tissue (WAT) expands in part through adipogenesis, a process involving fat cell generation and fatty acid (FA) storage into triglycerides (TGs). Several findings suggest that inter-individual and regional variations in adipogenesis are linked to metabolic complications. We aimed to identify cellular markers that define human adipocyte progenitors (APs) with pronounced adipogenic/TG storage ability. Using an unbiased single cell screen of passaged human adipose-derived stromal cells (hADSCs), we identified cell clones with similar proliferation rates but discordant capabilities to undergo adipogenic differentiation. Transcriptomic analyses prior to induction of differentiation showed that adipogenic clones displayed a significantly higher expression of CD36, encoding the scavenger receptor CD36. CD36+ hADSCs, in comparison with CD36-cells, displayed almost complete adipogenic differentiation while CD36 RNAi attenuated lipid accumulation. Similar findings were observed in primary CD45-/CD34+/CD31-APs isolated from human WAT where the subpopulation of MSCA1+/CD36+ cells displayed a significantly higher differentiation degree/TG storage capacity than MSCA1+/CD36-cells. Functional analyses in vitro and ex vivo confirmed that CD36 conferred APs an increased capacity to take up FAs thereby facilitating terminal differentiation. Among primary APs from subcutaneous femoral, abdominal and visceral human WAT, the fraction of CD36+ cells was significantly higher in depots associated with higher adipogenesis and reduced metabolic risk (i.e., femoral WAT). We conclude that CD36 marks APs with pronounced adipogenic potential, most probably by facilitating lipid uptake. This may be of value in developing human adipocyte cell clones and possibly in linking regional variations in adipogenesis to metabolic phenotype. Stem Cells 2017;35:1799-1814.

Human white and brite adipogenesis is supported by MSCA1 and is impaired by immune cells.

Obesity-associated inflammation contributes to the development of metabolic diseases. Although brite adipocytes have been shown to ameliorate metabolic parameters in rodents, their origin and differentiation remain to be characterized in humans. Native CD45-/CD34+/CD31- cells have been previously described as human adipocyte progenitors. Using two additional cell surface markers, MSCA1 (tissue nonspecific alkaline phosphatase) and CD271 (nerve growth factor receptor), we are able to partition the CD45-/CD34+/CD31- cell population into three subsets. We establish serum-free culture conditions without cell expansion to promote either white/brite adipogenesis using rosiglitazone, or bone morphogenetic protein 7 (BMP7), or specifically brite adipogenesis using 3-isobuthyl-1-methylxanthine. We demonstrate that adipogenesis leads to an increase of MSCA1 activity, expression of white/brite adipocyte-related genes, and mitochondriogenesis. Using pharmacological inhibition and gene silencing approaches, we show that MSCA1 activity is required for triglyceride accumulation and for the expression of white/brite-related genes in human cells. Moreover, native immunoselected MSCA1+ cells exhibit brite precursor characteristics and the highest adipogenic potential of the three progenitor subsets. Finally, we provided evidence that MSCA1+ white/brite precursors accumulate with obesity in subcutaneous adipose tissue (sAT), and that local BMP7 and inflammation regulate brite adipogenesis by modulating MSCA1 in human sAT. The accumulation of MSCA1+ white/brite precursors in sAT with obesity may reveal a blockade of their differentiation by immune cells, suggesting that local inflammation contributes to metabolic disorders through impairment of white/brite adipogenesis. Stem Cells 2015;33:1277-1291.

Long-term evolution of nutritional deficiencies after gastric bypass: an assessment according to compliance to medical care.

OBJECTIVE: To study long-term nutritional deficits based on adherence to a standardized nutritional care after gastric bypass (GBP). BACKGROUND: Long-term prospective data on nutritional complications after GBP are missing. It is not known whether severe deficiencies are prevented by standard multivitamin supplementation and what parameters are influenced by patient adherence to nutritional care. DESIGN: One hundred forty-four consecutive subjects from our prospective database (90% women, initial body mass index: 48 ± 15 kg/m2, age: 43 ± 10 years) who underwent GBP more than 3 years before the study were assessed. Multivitamins were systematically prescribed after GBP, and additional supplements were introduced if deficiencies were recorded during follow-up. We identified a group of 66 compliant subjects who attended yearly medical visits and a group of 32 noncompliant subjects who were recalled because they had not attended any visit for more than 2 years. RESULTS: Weight loss was 42 ± 14 kg at 3 years or later. The number of nutritional deficits per subject was 3.2 ± 2.3 before surgery and did not significantly increase between 1 and 3 years or later after GBP (3.4 ± 2.0 and 3.5 ± 2.3, respectively). However, specific nutritional deficits occurred despite long-term multivitamin supplementation, including vitamins B1, B12, and D and iron. Noncompliant subjects had more deficits than compliant subjects (4.2 ± 1.9 vs 2.9 ± 2.0 deficits per patient, P < 0.01) and the number of deficits correlated with the time from last visit (r = 0.285, P < 0.01). CONCLUSIONS: Lifelong medical care is required to maintain a good nutritional status after GBP. Monitoring of nutritional parameters is necessary to add supplementation for deficits that are not prevented by multivitamin preparations.

Comparison of pregnancy outcomes after bariatric surgery by sleeve gastrectomy versus gastric bypass.

Objective: Bariatric surgery has an impact on subsequent pregnancies, in particular an association between gastric bypass and small for gestational age. Knowledge is lacking on whether sleeve gastrectomy is associated with more favorable pregnancy outcomes. This study aimed to compare the impact of sleeve gastrectomy and Roux-en-Y gastric bypass on the incidence of small for gestational age (SGA), and of adverse pregnancy outcomes. Study design: We conducted a retrospective study in a single reference center, including all patients with a history of sleeve or bypass who delivered between 2004 and 2021 after their first pregnancy following bariatric surgery. We compared the incidence of SGA, intrauterine growth retardation, preterm delivery and adverse maternal outcomes between patients who had sleeve versus bypass. Results: Of 244 patients, 145 had a sleeve and 99 had a bypass. The proportion of SGA < 10th percentile did not differ between the two groups (38/145 (26.2 %) vs 22/99 (22.22 %), respectively, p = 0.48). Preterm birth < 37 WG was lower in the sleeve group (5/145 (3.45%) vs 12/99 (12.12 %) in the bypass group (p = 0.01), as well as NICU hospitalizations (3 (2.07%) vs 12/99 (12.12%), p < 0.01). There was no difference regarding adverse maternal outcomes such as gestational diabetes and hypertensive complications. The proportion of SGA was not lower in patients with bypass when adjusting for other risk factors (BMI, smoking, geographic origin, diabetes and hypertension) (aOR 0.70; 95%CI 0.01 - 2.85). Conclusion: sleeve was associated with an incidence of SGA which was as high as after bypass, however the incidence of preterm birth was lower.

Long-Term Differential Effects of Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density.

Context: The association of obesity with bone fragility fractures is complex and non-linear. Despite good efficacy on weight loss, bariatric surgery (BS) is also associated with bone loss. However, we lack information on risk factors of the long-term deleterious effects of BS on the skeleton. Objective: We aimed to assess the factors associated with low bone mineral density (BMD) performed a long time after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Methods: This cross-sectional study involved patients at a long distance from their BS that underwent dual-energy x-ray absorptiometry (DXA) with biological factors (vitamins, micronutrients, bone and inflammation biomarkers). Simple and multiple linear models (stepwise and parsimony approach) were developed. Results: A total of 131 patients (91 RYGB, 40 SG) underwent DXA (51.8 ± 11.08 years, 87.8% women). At a mean of 6.8 ± 3.7 years after surgery, the mean weight loss was -28.6 ± 9.6%, and only 6 patients (5.7%) had a T-score less than or equal to -2.5. On univariate analysis, BMD was lower in the RYGB than in the SG group (P < .001) at all sites, despite similar fat and fat-free mass and weight loss. Serum parathyroid hormone and phosphate levels were higher in RYGB than SG patients. A total of 10.1% of patients showed vascular calcifications. On multivariable analysis, BMD remained different between surgery groups after adjustment for age, body mass index, ethnicity, and sex. The model-adjusted R 2 values were 0.451 for the total hip; 0.462 the femoral neck, and 0.191 the lumbar spine for the inflammation model; 0.458, 0.462, and 0.254, respectively, for the bone marker model; and 0.372, 0.396, and 0.142 for the vitamin model. Serum zinc, ferritin, and uric acid levels were the markers associated with BMD to a low extent. Conclusion: BMD differed depending on the BS procedure. A few biological markers may be associated weakly with BMD well after the surgery.

Endoscopic Follow-Up Between 3 and 7 Years After Sleeve Gastrectomy Reveals Antral Reactive Gastropathy but no Barrett's Esophagus.

BACKGROUND: The main concerns following sleeve gastrectomy (SG) include the risk of gastroesophageal reflux disease (GERD) and its complications, such as Barrett's esophagus (BE). However, there is conflicting data on esophageal conditions, and studies on alterations of gastric mucosa after SG are lacking, despite reported cases of gastric cancer. Our aim was to assess esophageal and gastric lesions after SG. METHODS: From November 2017, an upper gastrointestinal endoscopy (UGE) was proposed at least 3 years after SG to all patients operated on in our institution. Endoscopic results and gastric histological findings were analyzed. BE was defined as endoscopically suspected esophageal metaplasia with histological intestinal metaplasia. RESULTS: Between September 2008 and August 2018, 375 patients underwent SG at our institution, of which 162 (43%) underwent at least one UGE 3 years or more after SG (91% women, mean preoperative age: 43.3±10.3 years). Despite a significant increase in the prevalence of symptomatic GERD, hiatal hernia, and esophagitis after SG (p<0.001 vs. preoperatively), no cases of BE were detected. Gastric dysplasia was not found and the prevalence of gastric atrophy tended to decrease after SG. However, 27% of patients with gastric biopsies developed antral reactive gastropathy. CONCLUSIONS: At a mean follow-up of 54 months after SG, no BE or gastric dysplasia was identified. However, reactive gastric lesions appeared, and their long-term consequences need to be further clarified. Thus, the timing of endoscopic follow-up, starting as early as 3 years after SG should be reevaluated to improve patient adherence with long-term endoscopies.

No Long-Term Mucosal Lesions in the Esophagus but More Gastric Mucosal Lesions after Sleeve Gastrectomy in Obese Rats.

Sleeve gastrectomy (SG) often induces gastroesophageal reflux, with few and discordant long-term data on the risk of Barrett's esophagus (BE) in operated patients. The aim of this study was to analyze the impact of SG on esogastric mucosa in a rat model at 24 weeks postoperatively, which corresponds to approximately 18 years in humans. After 3 months of a high-fat diet, obese male Wistar rats were subjected to SG (n = 7) or sham surgery (n = 9). Esophageal and gastric bile acid (BA) concentrations were measured at sacrifice, at 24 weeks postoperatively. Esophageal and gastric tissues were analyzed by routine histology. The esophageal mucosa of the SG rats (n = 6) was not significantly different in comparison to that of the sham rats (n = 8), with no esophagitis or BE. However, there was more antral and fundic foveolar hyperplasia in the mucosa of the residual stomach 24 weeks after SG than in the sham group (p < 0.001). Luminal esogastric BA concentrations did not differ between the two groups. In our study, SG induced gastric foveolar hyperplasia but no esophageal lesions at 24 weeks postoperatively in obese rats. Therefore, long-term endoscopic esophageal follow-up that is recommended in humans after SG to detect BE may also be useful for detecting gastric lesions.

Notch activation shifts the fate decision of senescent progenitors toward myofibrogenesis in human adipose tissue.

Senescence is a key event in the impairment of adipose tissue (AT) function with obesity and aging but the underlying molecular and cellular players remain to be fully defined, particularly with respect to the human AT progenitors. We have found distinct profiles of senescent progenitors based on AT location between stroma from visceral versus subcutaneous AT. In addition to flow cytometry, we characterized the location differences with transcriptomic and proteomic approaches, uncovering the genes and developmental pathways that are underlying replicative senescence. We identified key components to include INBHA as well as SFRP4 and GREM1, antagonists for the WNT and BMP pathways, in the senescence-associated secretory phenotype and NOTCH3 in the senescence-associated intrinsic phenotype. Notch activation in AT progenitors inhibits adipogenesis and promotes myofibrogenesis independently of TGFß. In addition, we demonstrate that NOTCH3 is enriched in the premyofibroblast progenitor subset, which preferentially accumulates in the visceral AT of patients with an early obesity trajectory. Herein, we reveal that NOTCH3 plays a role in the balance of progenitor fate determination preferring myofibrogenesis at the expense of adipogenesis. Progenitor NOTCH3 may constitute a tool to monitor replicative senescence and to limit AT dysfunction in obesity and aging.

Taste-Driven Responsiveness to Fat and Sweet Stimuli in Mouse Models of Bariatric Surgery.

A preferential consumption of healthier foods, low in fat and sugar, is often reported after bariatric surgery, suggesting a switch of taste-guided food choices. To further explore this hypothesis in well-standardized conditions, analysis of licking behavior in response to oily and sweet solutions has been realized in rats that have undergone a Roux-en-Y bypass (RYGB). Unfortunately, these studies have produced conflicting data mainly due to methodological differences. Paradoxically, whereas the vertical sleeve gastrectomy (VSG) becomes the most commonly performed bariatric surgery worldwide and is easier to perform and standardize in small animals, its putative impacts on the orosensory perception of energy-dense nutrients remains unknown. Using brief-access licking tests in VSG or RYGB mice, we found that (i) VSG induces a significant reduction in the fat mass in diet-induced obese (DIO) mice, (ii) VSG partially corrects the licking responses to lipid and sucrose stimuli which are degraded in sham-operated DIO mice, (iii) VSG improves the willingness to lick oily and sucrose solutions in DIO mice and (iv) RYGB leads to close outcomes. Altogether, these data strongly suggest that VSG, as RYGB, can counteract the deleterious effect of obesity on the orosensory perception of energy-dense nutrients in mice.

Conversion of One Anastomosis Gastric Bypass to Roux-en-Y Gastric Bypass: Results of a Retrospective Multicenter Study.

BACKGROUND: One anastomosis gastric bypass (OAGB) may expose the patient to certain specific complications. Here, we report the results of conversion of OAGB to Roux-en-Y gastric bypass (RYGB) in terms of outcomes and weight loss. METHODS: Between January 2009 and January 2019, all patients undergoing conversion of OAGB to RYGB because of complications due to OAGB (n = 23) were included. The primary efficacy endpoint was the effectiveness of converting OAGB to RYGB. The secondary endpoints were overall mortality and morbidity during the first 3 postoperative months, specific morbidity, reoperation, length of hospitalization, weight loss, and progression of comorbidities related to obesity at 2-year follow-up. RESULTS: Indications for conversion were bile reflux (n = 14; 60.9%), severe malnutrition (n = 3; 13%), gastro-gastric fistula (n = 4; 17.4%), and anastomotic leak (n = 2; 8.7%). The median time interval between OAGB and conversion to RYGB was 34 months (0-158). At the time of RYGB, median body mass index (BMI) was 28.0 kg/m2 (18.2-50.7), representing a median BMI change of 14.0 (- 1.7-43.5). Fifteen surgeries (65.1%) were completed laparoscopically. Five complications (21.7%) were recorded, including 2 major ones (8.7%). Reoperation rate was 4.3% (n = 1). At 24 months of follow-up (n = 18; 78.3%), median BMI was 28.7 kg/m2 (19.4-35.4), representing a median BMI change of 19.5 (12.2-43.1). No patient complained of bile reflux or persistent malnutrition. CONCLUSION: RYGB performed as revisional surgery for complications after OAGB is an effective procedure with no major weight regain at 2 years of follow-up.

[Nutritionnal complications and patients follow-up after bariatric surgery]. / Complications nutritionnelles de la chirurgie bariatrique et surveillance des patients opérés.

NUTRITIONNAL COMPLICATIONS AND PATIENTS FOLLOW-UP AFTER BARIATRIC SURGERYBariatric surgery is the most consistently effective method for sustained weight reduction and can result in a substantial improvement in overall survival in patients with severe obesity. Complex mechanisms underlying metabolic benefits could also drive preventable, but potentially life-threatening, long-term nutritional complications. Consequently, physicians should be familiar with the lifelong monitoring of patients after bariatric surgery and the potential long-term complications in this paradoxical situation where the long-awaited weight loss can lead to severe nutritional complications.

COMPLICATIONS NUTRITIONNELLES DE LA CHIRURGIE BARIATRIQUE ET SURVEILLANCE DES PATIENTS OPÉRÉS La chirurgie bariatrique est le traitement le plus efficace en termes de perte pondérale durable et de réduction de la morbi-mortalité en cas d'obésité sévère. Cependant, les modifications profondes de la physiologie digestive qui sous-tendent ces bénéfices métaboliques peuvent entraîner des carences nutritionnelles qui peuvent induire des complications sévères et irréversibles. La population des patients bariatriques étant en constante augmentation, tout médecin peut être amené à prendre un charge un patient opéré. Il devrait donc connaître les principes de la surveillance à vie et les possibles complications à long terme dans cette situation si paradoxale où la perte de poids tant attendue peut aussi s'associer à des carences potentiellement sévères.

A specific tongue microbiota signature is found in patients displaying an improvement of orosensory lipid perception after a sleeve gastrectomy.

Introduction: A preferential consumption of low-fat foods is reported by most of the patients after a vertical sleeve gastrectomy (VSG). The fact that a recent study shed light on a relationship between oral microbiota and fat taste sensitivity in obese patients prompted us to explore whether such a connection also exists in the context of a VSG. Methods: Thirty-two adult female patients with a severe obesity (BMI = 43.1 ± 0.7 kg/m2) and candidates for a VSG were selected. Oral microbiota composition surrounding the gustatory circumvallate papillae (CVP) and the lipid perception thresholds were explored before and 6 months after surgery. Results: VSG was found to be associated both with a qualitative (compositional changes) and quantitative (lower gene richness) remodeling of the peri-CVP microbiota. Analysis of the lipid perception allowed us to distinguish two subgroups: patients with a post-operative improvement of the fat taste sensitivity (i.e., with a lower threshold, n = 14) and unimproved patients (n = 18). Specific peri-CVP microbiota signatures also discriminated these two subgroups, unimproved patient being characterized by higher levels of Porphyromonas, Fusobacterium, and Haemophilus genera associated with lower levels of Atopobium and Prevotella genera as compared to the lipid-improved patients. Conclusion: Collectively, these data raise the possibility that the microbial environment surrounding gustatory papillae might play a role in the positive changes of fat taste sensitivity observed in some patients after VSG.

Subcutaneous Stromal Cells and Visceral Adipocyte Size Are Determinants of Metabolic Flexibility in Obesity and in Response to Weight Loss Surgery.

Adipose tissue (AT) expansion either through hypertrophy or hyperplasia is determinant in the link between obesity and metabolic alteration. The present study aims to profile the unhealthy subcutaneous and visceral AT (SAT, VAT) expansion in obesity and in the outcomes of bariatric surgery (BS). The repartition of adipocytes according to diameter and the numbers of progenitor subtypes and immune cells of SAT and VAT from 161 obese patients were determined by cell imaging and flow cytometry, respectively. Associations with insulin resistance (IR) prior to BS as well as with the loss of excessive weight (EWL) and IR at 1 and 3 years post-BS were studied; prior to BS, SAT and VAT, unhealthy expansions are characterized by the accumulation of adipogenic progenitors and CD4+ T lymphocytes and by adipocyte hypertrophy and elevated macrophage numbers, respectively. Such SAT stromal profile and VAT adipocyte hypertrophy are associated with adverse BS outcomes. Finally, myofibrogenic progenitors are a common determinant of weight and IR trajectories post-BS; the study suggests that adipogenesis in SAT and adipocyte hypertrophy in VAT are common determinants of metabolic alterations with obesity and of the weight loss and metabolic response to bariatric surgery. The data open up new avenues to better understand and predict individual outcomes in response to changes in energy balance.

Prevention and treatment of nutritional complications after bariatric surgery.

Obesity and the corresponding burden of related diseases is a major public health issue worldwide that is reaching pandemic proportions. Bariatric surgery is the only intervention that has been shown to result in substantial and lasting weight loss, and a decrease in overall mortality for patients with severe obesity. Consequently, the population of patients having undergone this procedure is increasing. Multifactorial weight-dependent and independent mechanisms underlying metabolic diseases could also drive preventable, but potentially life-threatening, long-term nutritional complications. However, given post-bariatric patients are prone to functional gastrointestinal symptoms and substantial weight loss, nutritional complications might be challenging. This Review is focused on the prevention and treatment of nutritional complications after bariatric surgery in the clinical setting.

Prospective comparison of transient elastography, MRI and serum scores for grading steatosis and detecting non-alcoholic steatohepatitis in bariatric surgery candidates.

BACKGROUND & AIMS: Tools for the non-invasive diagnosis of non-alcoholic steatohepatitis (NASH) in morbidly obese patients with suspected non-alcoholic fatty liver disease (NAFLD) are an unmet clinical need. We prospectively compared the performance of transient elastography, MRI, and 3 serum scores for the diagnosis of NAFLD, grading of steatosis and detection of NASH in bariatric surgery candidates. METHODS: Of 186 patients screened, 152 underwent liver biopsy, which was used as a reference for NAFLD (steatosis [S]>5%), steatosis grading and NASH diagnosis. Biopsies were read by a single expert pathologist. MRI-based proton density fat fraction (MRI-PDFF) was measured in an open-bore, vertical field 1.0T scanner and controlled attenuation parameter (CAP) was measured by transient elastography, using the XL probe. Serum scores (SteatoTest, hepatic steatosis index and fatty liver index) were also calculated. RESULTS: The applicability of MRI was better than that of FibroScan (98% vs. 79%; p <0.0001). CAP had AUROCs of 0.83, 0.79, 0.73 and 0.69 for S>5%, S>33%, S>66% and NASH, respectively. Transient elastography had an AUROC of 0.80 for significant fibrosis (F0-F1 vs. F2-F3). MRI-PDFF had AUROCs of 0.97, 0.95, 0.92 and 0.84 for S>5%, S>33%, S>66% and NASH, respectively. When compared head-to-head in the 97 patients with all valid tests available, MRI-PDFF outperformed CAP for grading steatosis (S>33%, AUROC 0.97 vs. 0.78; p <0.0003 and S>66%, AUROC 0.93 vs. 0.75; p = 0.0015) and diagnosing NASH (AUROC 0.82 vs. 0.68; p = 0.0056). When compared in "intention to diagnose" analysis, MRI-PDFF outperformed CAP, hepatic steatosis index and fatty liver index for grading steatosis (S>5%, S>33% and S>66%). CONCLUSION: MRI-PDFF outperforms CAP for diagnosing NAFLD, grading steatosis and excluding NASH in morbidly obese patients undergoing bariatric surgery. LAY SUMMARY: Non-invasive tests for detecting fatty liver and steatohepatitis, the active form of the disease, have not been well studied in obese patients who are candidates for bariatric surgery. The most popular tests for this purpose are Fibroscan, which can be used to measure the controlled attenuation parameter (CAP), and magnetic resonance imaging, which can be used to measure the proton density fat fraction (MRI-PDFF). We found that, when taking liver biopsy as a reference, MRI-PDFF performed better than CAP for detecting and grading fatty liver as well as excluding steatohepatitis in morbidly obese patients undergoing bariatric surgery.

Orosensory Perception of Fat/Sweet Stimuli and Appetite-Regulating Peptides before and after Sleeve Gastrectomy or Gastric Bypass in Adult Women with Obesity.

The aim of this study was to explore the impact of bariatric surgery on fat and sweet taste perceptions and to determine the possible correlations with gut appetite-regulating peptides and subjective food sensations. Women suffering from severe obesity (BMI > 35 kg/m2) were studied 2 weeks before and 6 months after a vertical sleeve gastrectomy (VSG, n = 32) or a Roux-en-Y gastric bypass (RYGB, n = 12). Linoleic acid (LA) and sucrose perception thresholds were determined using the three-alternative forced-choice procedure, gut hormones were assayed before and after a test meal and subjective changes in oral food sensations were self-reported using a standardized questionnaire. Despite a global positive effect of both surgeries on the reported gustatory sensations, a change in the taste sensitivity was only found after RYGB for LA. However, the fat and sweet taste perceptions were not homogenous between patients who underwent the same surgery procedure, suggesting the existence of two subgroups: patients with and without taste improvement. These gustatory changes were not correlated to the surgery-mediated modifications of the main gut appetite-regulating hormones. Collectively these data highlight the complexity of relationships between bariatric surgery and taste sensitivity and suggest that VSG and RYGB might impact the fatty taste perception differently.

The Tryptophan/Kynurenine Pathway: A Novel Cross-Talk between Nutritional Obesity, Bariatric Surgery and Taste of Fat.

Diet-induced obesity (DIO) reduces the orosensory perception of lipids in rodents and in some humans. Although bariatric surgery partially corrects this alteration, underlying mechanisms remain poorly understood. To explore whether metabolic changes might explain this fat taste disturbance, plasma metabolome analyses, two-bottle choice tests and fungiform papillae (Fun) counting were performed in vertical sleeve gastrectomized (VSG) mice and sham-operated controls. An exploratory clinic study was also carried out in adult patients undergone a VSG. In mice, we found that (i) the VSG reduces both the plasma neurotoxic signature due to the tryptophan/kynurenine (Trp/Kyn) pathway overactivation and the failure of fat preference found in sham-operated DIO mice, (ii) the activity of Trp/Kyn pathway is negatively correlated to the density of Fun, and (iii) the pharmacological inhibition of the Kyn synthesis mimics in non-operated DIO mice the positive effects of VSG (i.e., decrease of Kyn synthesis, increase of Fun number, improvement of the fat taste perception). In humans, a reduction of the plasma Kyn level is only found in patients displaying a post-surgery improvement of their fat taste sensitivity. Altogether these data provide a plausible metabolic explanation to the degradation of the orosensory lipid perception observed in obesity.

Do Preoperative Esophageal pH Monitoring and High-Resolution Manometry Predict Symptoms of GERD After Sleeve Gastrectomy?

BACKGROUND: Predictive factors of evolution or appearance of gastroesophageal reflux disease (GERD) after sleeve gastrectomy (SG) have not been identified to date. We aimed to assess the evolution of GERD symptoms 1 year after SG and to determine preoperative predictive factors using high-resolution manometry (HRM) and ambulatory 24-h esophageal pH monitoring (APM). METHODS: We included 160 patients who underwent SG between 2013 and 2017 and performed preoperative APM and HRM. Positive APM was defined according to the Lyon consensus. Symptoms of GERD, proton pump inhibitors (PPI) use, weight loss (WL), and diet were recorded in all patients before and 1 year after surgery. RESULTS: One year after surgery, 58 patients (36.3%) complained of GERD symptoms compared to 52 patients (32.5%) preoperatively (p=0.48). Among patients with preoperative GERD symptoms, only 26/52 patients (50%) still had symptoms, whereas 32/108 (29.6%) asymptomatic patients developed de novo GERD symptoms after surgery. PPI use increased after surgery reaching 36.9% of patients against 15.0% before (p<0.0001). Only preoperative symptoms of GERD were predictive of postoperative symptoms (OR= 2.47 [1.14-5.45]; p=0.023) in multivariate analysis. Preoperative manometric parameters, postoperative diet, and WL were not related to postoperative symptoms. In asymptomatic patients before surgery, silent GERD (positive APM without symptom) was predictive of postoperative GERD symptoms (OR=2.69 [1.00-7.25]; p=0.049). CONCLUSION: Evolution of GERD symptoms after SG reveals improvement for half of the patients and de novo GERD symptoms in one-third of patients. Predictive factors of postoperative symptoms are preoperative symptoms and positive preoperative APM in asymptomatic patients.