Networks of gut bacteria relate to cardiovascular disease in a multi-ethnic population: the HELIUS study

AIMS

Gut microbiota have been linked to blood lipid levels and cardiovascular diseases (CVDs). The composition and abundance of gut microbiota trophic networks differ between ethnicities. We aim to evaluate the relationship between gut microbiotal trophic networks and CVD phenotypes.

METHODS AND RESULTS

We included cross-sectional data from 3860 individuals without CVD history from 6 ethnicities living in the Amsterdam region participating in the prospective Healthy Life in Urban Setting (HELIUS) study. Genetic variants were genotyped, faecal gut microbiota were profiled, and blood and anthropometric parameters were measured. A machine learning approach was used to assess the relationship between CVD risk (Framingham score) and gut microbiota stratified by ethnicity. Potential causal relationships between gut microbiota composition and CVD were inferred by performing two-sample Mendelian randomization with hard CVD events from the Pan-UK Biobank and microbiome genome-wide association studies summary data from a subset of the HELIUS cohort (n = 4117). Microbial taxa identified to be associated with CVD by machine learning and Mendelian randomization were often ethnic-specific, but some concordance across ethnicities was found. The microbes Akkermansia muciniphila and Ruminococcaceae UCG-002 were protective against ischaemic heart disease in African-Surinamese and Moroccans, respectively. We identified a strong inverse association between blood lipids, CVD risk, and the combined abundance of the correlated microbes Christensenellaceae-Methanobrevibacter-Ruminococcaceae (CMR). The CMR cluster was also identified in two independent cohorts and the association with triglycerides was replicated.

CONCLUSION

Certain gut microbes can have a potentially causal relationship with CVD events, with possible ethnic-specific effects. We identified a trophic network centred around Christensenellaceae, Methanobrevibacter, and various Ruminococcaceae, frequently lacking in South-Asian Surinamese, to be protective against CVD risk and associated with low triglyceride levels.

Osteoarthritis in patients with obesity: The bariatric surgery impacts on its evolution

Obesity is one of the main modifiable risk factors for osteoarthritis (OA). Moreover, obesity is associated with greater pain intensity and functional limitation, but also with a significantly lower responder rate to intra-articular treatments. Consequently, an arthroplasty is indicated earlier and more frequently in patients with obesity. However, pain and functional symptoms improve slightly less after arthroplasty in patients with obesity, who display higher incidence of early and late complications following prosthetic surgery. Bariatric surgery (BS) has increased worldwide and is efficient to induce major and sustainable weight-loss. Importantly, BS significantly reduces pain and functional limitation in patients with symptomatic knee OA. Biomarkers analysis also revealed a decrease in catabolic factors and an increase in anabolic one after BS suggesting a structural protective effect in knee OA. Nevertheless, the impact of BS prior to arthroplasty remains unclear. BS seems to decrease short- and mid-term complications such as infections or thrombosis. However, BS does not appear to modify long-term complications rate, and may even increase it, especially revisions and infections. Although few studies have compared the symptomatic and functional outcomes of joint replacement with or without BS, these are not significantly improved by prior BS. Despite these heterogeneous results, medico-economic studies found that BS prior to arthroplasty was cost-effective. To conclude, BS could significantly reduce the symptoms of OA and potentially slow its progression, but appears more disappointing in preventing long-term complications of arthroplasties and improving their functional results.

Management of Severe Malnutrition Post-bariatric Surgery Using Artificial Nutrition

BACKGROUND

Bariatric surgery (BS) results in major and sustained weight loss and improves comorbidities in patients with obesity but can also lead to malnutrition, especially through severe malabsorption and/or surgical complications. Little is known about the efficacy of artificial nutrition (AN) in this setting.

METHODS

In this case series, we describe data from consecutive severely malnourished patients after BS (resectional and non-resectional), managed by AN at our hospital unit over a 4-year period.

RESULTS

Between January 2018 and June 2022, 18 patients (mean ± SD age 42.2 ± 10.4 years, 94% women) required AN following BS complications. At the time of AN initiation, more than half of the patients (53%) had multiple revisional surgeries (up to four). Mean BMI was 49.7 ± 11.3 kg/m2 before BS and 29.6 ± 9.6 kg/m2 when AN was initiated. Most patients (n=16, 90%) received enteral nutrition. AN management resulted in weight regain (+4.7kg ± 8.0, p=0.034), increased serum albumin (+28%, p=0.02), pre-albumin (+88%, p=0.002), and handgrip strength (+38%, p=0.078). No major AN complication nor death was observed. Median total AN duration was 4.5 months [1-12]. During follow-up, the cumulative duration of hospitalization was 33 days [4-88] with a median of 2.5 hospitalizations [1-8] per patient.

CONCLUSION

Malnutrition can occur after any BS procedure, and AN when required in this setting appears safe and effective on nutritional parameters. It is important to recognize the potential risk factors for malnutrition, which include excessive weight loss resulting from surgical complications, eating disorders, multiple revisional BS, and pregnancy.

French National Authority for Health assessment of metabolic surgery for type 2 diabetes remission-A meta-analysis in patients with class I to III obesity

OBJECTIVE

Randomized controlled trials (RCTs) have demonstrated the superiority of metabolic surgery (MS) over medical therapy (MT) in patients with obesity and type 2 diabetes, leading, to a joint statement in 2016 proposing MS to patients with class I obesity and uncontrolled glycemia. Yet, these RCTs included few patients with class I obesity (body mass index 30-35 kg/m2) and even fewer patients with overweight. Our aim was to provide an updated systematic review (SR) with meta-analysis (MA) of RCTs reporting diabetes remission (DR) after MS in these patients.

RESEARCH DESIGN AND METHODS

We included in the SR with MA only RCTs with at least 24-month follow-up found in Medline, Cochrane Library, Embase, and LiSSA between January 2008 and September 2022 comparing DR post-MT versus post-MS. We calculated relative risk (RR) and 95 % confidence intervals (CIs) using the Mantel-Haenszel random-effects approach to examine differences in DR between patients allocated to MS versus MT.

RESULTS

DR was significantly higher in MS versus MT after 36 months' follow-up in patients with obesity (RR = 6.65 [95 %CI 2.24;19.79]; I² = 27 %; 5 trials, 404 patients), but also specifically in patients with class I obesity (RR = 5.27 [1.31;21.23]; I² = 0 %; 4 trials, 80 patients). Furthermore, and in line with previous results, all additional MAs performed in patients with obesity in this work favor MS (specifically Roux-en-Y gastric bypass) over MT at 24, 36 (only) and 60 months of follow-up.

CONCLUSIONS

Although the data available in patients with class I obesity and type 2 diabetes remains limited, MA shows higher rates of DR after MS compared with MT after 36 months' follow-up in these patients. Consequently, the French National Authority for Health French (HAS) recommends MS for these patients.

Out-of-Pocket Expenses in Households of People Living with Obesity in France

BACKGROUND/OBJECTIVES

Overweight and obesity result in a substantial economic burden in both low- and high-income countries. Moreover, this burden is often underestimated because it only partially accounts for unreimbursed out-of-pocket expenses (OOPE) related to obesity. The objective of our study was not only to evaluate OOPE incurred by people with obesity in relation to their disease with respect to direct medical expenditures and direct non-medical expenditures but also the proportion of people living with obesity who have forgone obesity-related healthcare due to the costs of such care.

METHODS

An observational descriptive survey was conducted among people with class II/III obesity attending six obesity treatment centers in France. Volunteer adult participants completed a written/phone questionnaire on their related expenditures over the last 6 months for current expenditures and over the last 5 years for occasional ones. The costs were expressed in 2022 EUR.

RESULTS

299 people participated (age: 46 years [SD: 13.9], women: 72%, BMI ≥40 kg/m2: 62% and 48% with comorbidities). 65% had a professional activity. 83% declared that they had OOPE related to obesity representing annually EUR 2027/individual on average (5% of the household revenue), including weight loss and nutritional products, vitamins, meal programs, gym memberships, psychologists, but mainly adapted clothing, additional travel costs, and others. 15% of the respondents had to modify their professional activity due to obesity and 15% forwent some medical care in the last 12 months.

CONCLUSIONS

OOPE is a significant part of the economic burden of obesity. Despite some limitations due to the specificities of the participants and because some costs may be more related to social activities affected by obesity than to healthcare, it seems important to consider these expenditures in cost estimates for obesity.

Revisional Roux-en-Y Gastric Bypass After Sleeve Gastrectomy for Gastro-esophageal Reflux Disease and or Insufficient Weight-Loss: a Comparative Study

INTRODUCTION

Sleeve gastrectomy (SG) is a popular surgical weight-loss procedure, but there are increasing reports of revisional Roux-Y-gastric-bypass (R-RYGB) to manage weight-loss failure (WLF) or proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) after SG, with little data available in these settings.

METHODS

This retrospective study included all consecutive patients undergoing R-RYGB for WLF or RGERD after SG in two bariatric care centers from 2012 to 2018.

RESULTS

Of 720 patients, 46 (3.6%) underwent R-RYGB (RGERD, n = 25; 54.4%; WLF, n = 21; 45.6%) within 44.8 ± 27.5 months post-SG. SG had enabled 27% ± 11.6 total weight loss (TWL) in the RGERD group vs. 7.2% ± 12.5% TWL in the WLF group (p < 0.001). At R-RYGB, WLF-group patients had a higher BMI (47.8 ± 8.4 vs. 34.7 ± 6.1 kg/m2; p < 0.001) and a higher number of comorbidities (2.4 ± 1.5 vs 1.5 ± 1.2; p < 0.02) compared to RGERD-group patients, while severe morbidity (Clavien-Dindo ≥ IIIb) was not significantly different between groups (6.5% vs 2.1%, p = 0.6). %TWL was still higher in the RGERD group at 12 months post-R-RYGB (35.6% ± 10.4 vs. 23.8% ± 9.2; p < 0.01) but not after 24 months post-R-RYGB. R-RYGB corrected reflux symptoms in 32 (94%) patients and reduced PPI use in 29 (97%) patients (p < 0.001), with no significant between-group difference. A history of adjustable gastric banding (AGB) (N = 8;17.4%) prior to SG was associated with a similar prevalence of GERD at R-RYGB and a lower %TWL (AGB:13.1 ± 10.2 vs. No AGB:31.6 ± 8.5; p < 0.05) at 3 years post-R-RYGB.

CONCLUSION

R-RYGB following SG provides remission of reflux symptoms in 94% of patients and extra weight loss in patients with WLF, except in patients with a history of AGB prior to SG.

Evidence of a causal and modifiable relationship between kidney function and circulating trimethylamine N-oxide

The host-microbiota co-metabolite trimethylamine N-oxide (TMAO) is linked to increased cardiovascular risk but how its circulating levels are regulated remains unclear. We applied "explainable" machine learning, univariate, multivariate and mediation analyses of fasting plasma TMAO concentration and a multitude of phenotypes in 1,741 adult Europeans of the MetaCardis study. Here we show that next to age, kidney function is the primary variable predicting circulating TMAO, with microbiota composition and diet playing minor, albeit significant, roles. Mediation analysis suggests a causal relationship between TMAO and kidney function that we corroborate in preclinical models where TMAO exposure increases kidney scarring. Consistent with our findings, patients receiving glucose-lowering drugs with reno-protective properties have significantly lower circulating TMAO when compared to propensity-score matched control individuals. Our analyses uncover a bidirectional relationship between kidney function and TMAO that can potentially be modified by reno-protective anti-diabetic drugs and suggest a clinically actionable intervention for decreasing TMAO-associated excess cardiovascular risk.

Microbially Produced Imidazole Propionate Is Associated With Heart Failure and Mortality

BACKGROUND

Over the past years, it has become clear that the microbial ecosystem in the gut has a profound capacity to interact with the host through the production of a wide range of bioactive metabolites. The microbially produced metabolite imidazole propionate (ImP) is clinically and mechanistically linked with insulin resistance and type 2 diabetes, but it is unclear how ImP is associated with heart failure.

OBJECTIVES

The authors aimed to explore whether ImP is associated with heart failure and mortality.

METHODS

ImP serum measurements in 2 large and independent clinical cohorts of patients (European [n = 1,985] and North American [n = 2,155]) with a range of severity of cardiovascular disease including heart failure. Univariate and multivariate Cox regression analyses were performed to delineate the impact of ImP on 5-year mortality in the North American cohort, independent of other covariates.

RESULTS

ImP is independently associated with reduced ejection fraction and heart failure in both cohorts, even after adjusting for traditional risk factors. Elevated ImP was a significant independent predictor of 5-year mortality (for the highest quartile, adjusted HR: 1.85 [95% CI: 1.20-2.88]; P < 0.01).

CONCLUSIONS

The gut microbial metabolite ImP is increased in individuals with heart failure and is a predictor of overall survival.

Associations of aortic stiffness and intra-aortic flow parameters with epicardial adipose tissue in patients with type-2 diabetes

Background

It has been shown that increased aortic stiffness is related to type-2 diabetes (T2D) which is considered as a risk factor for cardiovascular disease. Among other risk factors is epicardial adipose tissue (EAT) which is increased in T2D and is a relevant biomarker of metabolic severity and adverse outcome.

Purpose

To assess aortic flow parameters in T2D patients as compared to healthy individuals and to evaluate their associations with EAT accumulation as an index of cardiometabolic severity in T2D patients.

Materials and methods

Thirty-six T2D patients as well as 29 healthy controls matched by age and sex were included in this study. Participants had cardiac and aortic MRI exams at 1.5 T. Imaging sequences included cine SSFP for left ventricle (LV) function and EAT assessment and aortic cine and phase-contrast imaging for strain and flow parameters quantification.

Results

In this study, we found LV phenotype to be characterized by concentric remodeling with decreased stroke volume index despite global LV mass within a normal range. EAT was increased in T2D patients compared to controls (p<0.0001). Moreover, EAT, a biomarker of metabolic severity, was negatively correlated to ascending aortic (AA) distensibility (p=0.048) and positively to the normalized backward flow volume (p=0.001). These relationships remained significant after further adjustment for age, sex and central mean blood pressure. In a multivariate model, presence/absence of T2D and AA normalized backward flow (BF) to forward flow (FF) volumes ratio are both significant and independent correlates of EAT.

Conclusion

In our study, aortic stiffness as depicted by an increased backward flow volume and decreased distensibility seems to be related to EAT volume in T2D patients. This observation should be confirmed in the future on a larger population while considering additional biomarkers specific to inflammation and using a longitudinal prospective study design.

Precision Bariatric/Metabolic Medicine and Surgery

Indications and techniques of bariatric surgery (BS) have constantly evolved in recent decades and now face new challenges [...].

Impaired Function of Solute Carrier Family 19 Leads to Low Folate Levels and Lipid Droplet Accumulation in Hepatocytes

Low serum folate levels are inversely related to metabolic associated fatty liver disease (MAFLD). The role of the folate transporter gene (SLC19A1) was assessed to clarify its involvement in lipid accumulation during the onset of MAFLD in humans and in liver cells by genomic, transcriptomic, and metabolomic techniques. Genotypes of 3 SNPs in a case-control cohort were initially correlated to clinical and serum MAFLD markers. Subsequently, the expression of 84 key genes in response to the loss of SLC19A1 was evaluated with the aid of an RT² profiler-array. After shRNA-silencing of SLC19A1 in THLE2 cells, folate and lipid levels were measured by ELISA and staining techniques, respectively. In addition, up to 482 amino acids and lipid metabolites were semi-quantified in SLC19A1-knockdown (KD) cells through ultra-high-performance liquid chromatography coupled with mass spectrometry. SNPs, rs1051266 and rs3788200, were significantly associated with the development of fatty liver for the single-marker allelic test. The minor alleles of these SNPs were associated with a 0.6/-1.67-fold decreased risk of developing MAFLD. When SLC19A1 was KD in THLE2 cells, intracellular folate content was four times lower than in wild-type cells. The lack of functional SLC19A1 provoked significant changes in the regulation of genes associated with lipid droplet accumulation within the cell and the onset of NAFLD. Metabolomic analyses showed a highly altered profile, where most of the species that accumulated in SLC19A1-KD-cells belong to the chemical groups of triacylglycerols, diacylglycerols, polyunsaturated fatty acids, and long chain, highly unsaturated cholesterol esters. In conclusion, the lack of SLC19A1 gene expression in hepatocytes affects the regulation of key genes for normal liver function, reduces intracellular folate levels, and impairs lipid metabolism, which entails lipid droplet accumulation in hepatocytes.

From Dyspnea to Skin Grafting: The Difficulties of Managing a Patient with Extreme Obesity

While the prevalence of severe obesity is increasing worldwide, caregivers are often challenged with the management of patients with extreme weight. A 30-year-old woman (weight 245 kg, body mass index 85 kg/m2) presented with dyspnea, for which investigations led to suspect pulmonary embolism. The patient's weight made it impossible to perform adapted imaging; thus, an empirical anticoagulant treatment was initiated. A hematoma of the thigh occurred as a consequence of a transient antivitamin K overdose, leading to a 15-cm necrotic wound worsened by a state of malnutrition. Multidisciplinary and comprehensive care was performed including wound trimming, antibiotics, skin grafting, treatment of malnutrition, and psychological support, but with marked difficulties due to the lack of adapted medical equipment and facilities as well as appropriate medical guidelines. Overall, 7 months of hospitalization including 4 months of physiotherapy and rehabilitation were needed before the patient could return home. This case highlights how difficult managing patients with extreme obesity can be and points to the importance for healthcare systems to adapt to the specific needs of these patients and to design specific guidelines for treatment dosage and malnutrition prevention and treatment in this setting.

Impairment of gut microbial biotin metabolism and host biotin status in severe obesity: effect of biotin and prebiotic supplementation on improved metabolism

OBJECTIVES

Gut microbiota is a key component in obesity and type 2 diabetes, yet mechanisms and metabolites central to this interaction remain unclear. We examined the human gut microbiome's functional composition in healthy metabolic state and the most severe states of obesity and type 2 diabetes within the MetaCardis cohort. We focused on the role of B vitamins and B7/B8 biotin for regulation of host metabolic state, as these vitamins influence both microbial function and host metabolism and inflammation.

DESIGN

We performed metagenomic analyses in 1545 subjects from the MetaCardis cohorts and different murine experiments, including germ-free and antibiotic treated animals, faecal microbiota transfer, bariatric surgery and supplementation with biotin and prebiotics in mice.

RESULTS

Severe obesity is associated with an absolute deficiency in bacterial biotin producers and transporters, whose abundances correlate with host metabolic and inflammatory phenotypes. We found suboptimal circulating biotin levels in severe obesity and altered expression of biotin-associated genes in human adipose tissue. In mice, the absence or depletion of gut microbiota by antibiotics confirmed the microbial contribution to host biotin levels. Bariatric surgery, which improves metabolism and inflammation, associates with increased bacterial biotin producers and improved host systemic biotin in humans and mice. Finally, supplementing high-fat diet-fed mice with fructo-oligosaccharides and biotin improves not only the microbiome diversity, but also the potential of bacterial production of biotin and B vitamins, while limiting weight gain and glycaemic deterioration.

CONCLUSION

Strategies combining biotin and prebiotic supplementation could help prevent the deterioration of metabolic states in severe obesity.

TRIAL REGISTRATION NUMBER

NCT02059538.

Epicardial adipose tissue of atrioventricular grooves is a reliable and early MRI biomarker of the effect of metabolic diseases on atrial myocardium

Introduction

Epicardial adipose tissue (EAT), the visceral adipose tissue surrounding the heart, is implicated in a host of cardiovascular diseases playing a transducer role between systemic metabolic conditions and the myocardium, as illustrated by higher risk of atrial fibrillation in patients with diabetes or obesity. MRI affords comprehensive and non-invasive insights into myocardial structure, function and tissue properties. However, the clinical usefulness of whole atrial EAT is limited by its challenging measurability in clinical routine in several imaging modalities, including MRI.

Purpose

We hypothesized that atrioventricular groove epicardial adipose tissue (GEAT) which can be measured routinely based on established anatomic landmarks may be: 1) a relevant surrogate of atrial EAT and 2) a relevant imaging biomarker to characterize atrial alterations in patients with varied degrees of metabolic disorders.

Methods

Ninety-nine patients from the METACARDIS cohort (EU FP7) who had MRI, all in sinus rhythm and without overt clinical heart disease, were divided into 4 groups based on distinct metabolic profiles: metabolic syndrome (MS, n=24), severe obesity (SO, BMI ≥35 kg/m2, n=17), type-2 diabetes (T2D, n=41) and healthy controls (n=17). Atrioventricular groove EAT volume was measured from cine SSFP MRI images in four-, three-, two-chamber and short-axis views; atrial EAT volume was measured from four- and two-chamber views. Native T1-mapping values of EAT at the anterior atrioventricular groove excluding the coronary vessels were measured from the MOLLI sequence (basal short-axis slice).

Results

We found a high correlation between GEAT and atrial EAT volumes (r=0.96; p&lt;0.0001) indicating that GEAT may reflect global atrial EAT volume. Next, we compared GEAT volume across study groups and found an increased GEAT volume in the 3 groups of patients with metabolic diseases compared to controls, with a significantly higher volume in MS (4.7±1.5 ml), SO (4.1±1.2 ml), and T2D (3.7±1.1 ml) than in Controls (2.6±0.6 ml; p≤0.001, p≤0.01, p≤0.05, respectively). In addition, T2D patients had lower native T1 values within GEAT compared to healthy controls (250±26 ms versus 280±31 ms; p≤0.01).

Conclusion

Atrioventricular groove EAT can be easily measured from conventional cine SSFP MRI images and could be used as a surrogate of global atrial EAT. Both volume and properties of GEAT are related to the metabolic status of patients. Furthermore, given its pure epicardial origin and pericoronary distribution, GEAT appears as a relevant biomarker of metabolic impacts on atrial myocardium.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Annee-recherche, Agence Regionale de Sante Ile-de-France

Persistence of severe liver fibrosis despite substantial weight loss with bariatric surgery

BACKGROUND AND AIMS

It remains unclear to what extent and which components of advanced liver disease improve after bariatric surgery. We herein describe the histological outcome in patients with advanced NASH and its relationship with weight loss and metabolic improvement.

APPROACH AND RESULTS

One hundred ninety-six patients with advanced NASH underwent bariatric surgery, 66 of whom agreed to a follow-up liver biopsy at 6 ± 3 years (36 with advanced fibrosis [AF] and 30 with high activity [HA] grade without AF). Liver biopsies LBs were centrally read and histological response was defined as the disappearance of AF or HA. Bariatric surgery induced major histological improvement: 29% of patients had normal histology at follow-up biopsy; 74% had NASH resolution without fibrosis progression; and 70% had ≥1 stage fibrosis regression. However, AF persisted in 47% of patients despite NASH resolution and some degree of fibrosis reversal, only evidenced by the EPoS seven-tier staging classification. These patients had lower weight loss and reduced hypertension or diabetes remission rates. Older age and sleeve gastrectomy were the only independent predictors for persistent AF after adjustment for duration of follow-up. All HA patients had major histological improvement: 50% normal histology, 80% NASH resolution, and 86% a ≥1 grade steatosis reduction. Patients with normal liver at follow-up had the largest weight loss and metabolic improvement. Independent predictors of normal liver were amount of weight loss, high histological activity, and the absence of AF before surgery.

CONCLUSIONS

Although bariatric surgery successfully reverses active steatohepatitis, AF can persist for many years and is associated with lesser weight loss and metabolic improvement. Weight loss alone may not be sufficient to reverse AF.

Effect of exercise training after bariatric surgery: A 5-year follow-up study of a randomized controlled trial

Background and objectives

We previously showed in a 6-month randomized controlled trial that resistance training and protein supplementation after bariatric surgery (Roux-en-Y gastric bypass, RYGB) improved muscle strength without significant effect on weight loss and body composition changes. We performed a 5-year follow-up study in these subjects with the aim 1) to assess the long-term effect of this exercise training intervention and 2) to analyze associations between habitual physical activity (PA) and weight regain at 5 years.

Methods

Fifty-four out of 76 initial participants (follow-up rate of 71%) completed the 5-year follow-up examination (controls, n = 17; protein supplementation, n = 22; protein supplementation and resistance training, n = 15). We measured body weight and composition (DXA), lower-limb strength (leg-press one-repetition maximum) and habitual PA (Actigraph accelerometers and self-report). Weight regain at 5 years was considered low when <10% of 12-month weight loss.

Results

Mean (SD) time elapse since RYGB was 5.7 (0.9) y. At 5 years, weight loss was 32.8 (10.1) kg, with a mean weight regain of 5.4 (SD 5.9) kg compared with the 12-month assessment. Moderate-to-vigorous PA (MVPA) assessed by accelerometry did not change significantly compared with pre-surgery values (+5.2 [SD 21.7] min/d, P = 0.059), and only 4 (8.2%) patients reported participation in resistance training. Muscle strength decreased over time (overall mean [SD]: -49.9 [53.5] kg, respectively, P<0.001), with no statistically significant difference between exercise training intervention groups. An interquartile increase in MVPA levels was positively associated with lower weight regain (OR [95% CI]: 3.27 [1.41;9.86]).

Conclusions

Early postoperative participation in a resistance training protocol after bariatric surgery was not associated with improved muscle strength after 5 years of follow-up; however, increasing physical activity of at least moderate intensity may promote weight maintenance after surgery. PA may therefore play an important role in the long-term management of patients with obesity after undergoing bariatric procedure.

The human gut microbiota contributes to type-2 diabetes non-resolution 5-years after Roux-en-Y gastric bypass

Roux-en-Y gastric bypass (RYGB) is efficient at inducing drastic albeit variable weight loss and type-2 diabetes (T2D) improvements in patients with severe obesity and T2D. We hypothesized a causal implication of the gut microbiota (GM) in these metabolic benefits, as RYGB is known to deeply impact its composition. In a cohort of 100 patients with baseline T2D who underwent RYGB and were followed for 5-years, we used a hierarchical clustering approach to stratify subjects based on the severity of their T2D (Severe vs Mild) throughout the follow-up. We identified via nanopore-based GM sequencing that the more severe cases of unresolved T2D were associated with a major increase of the class Bacteroidia, including 12 species comprising Phocaeicola dorei, Bacteroides fragilis, and Bacteroides caecimuris. A key observation is that patients who underwent major metabolic improvements do not harbor this enrichment in Bacteroidia, as those who presented mild cases of T2D at all times. In a separate group of 36 patients with similar baseline clinical characteristics and preoperative GM sequencing, we showed that this increase in Bacteroidia was already present at baseline in the most severe cases of T2D. To explore the causal relationship linking this enrichment in Bacteroidia and metabolic alterations, we selected 13 patients across T2D severity clusters at 5-years and performed fecal matter transplants in mice. Our results show that 14 weeks after the transplantations, mice colonized with the GM of Severe donors have impaired glucose tolerance and insulin sensitivity as compared to Mild-recipients, all in the absence of any difference in body weight and composition. GM sequencing of the recipient animals revealed that the hallmark T2D-severity associated bacterial features were transferred and were associated with the animals' metabolic alterations. Therefore, our results further establish the GM as a key contributor to long-term glucose metabolism improvements (or lack thereof) after RYGB.

Dysregulation of macrophage PEPD in obesity determines adipose tissue fibro-inflammation and insulin resistance

Resulting from impaired collagen turnover, fibrosis is a hallmark of adipose tissue (AT) dysfunction and obesity-associated insulin resistance (IR). Prolidase, also known as peptidase D (PEPD), plays a vital role in collagen turnover by degrading proline-containing dipeptides but its specific functional relevance in AT is unknown. Here we show that in human and mouse obesity, PEPD expression and activity decrease in AT, and PEPD is released into the systemic circulation, which promotes fibrosis and AT IR. Loss of the enzymatic function of PEPD by genetic ablation or pharmacological inhibition causes AT fibrosis in mice. In addition to its intracellular enzymatic role, secreted extracellular PEPD protein enhances macrophage and adipocyte fibro-inflammatory responses via EGFR signalling, thereby promoting AT fibrosis and IR. We further show that decreased prolidase activity is coupled with increased systemic levels of PEPD that act as a pathogenic trigger of AT fibrosis and IR. Thus, PEPD produced by macrophages might serve as a biomarker of AT fibro-inflammation and could represent a therapeutic target for AT fibrosis and obesity-associated IR and type 2 diabetes.

Fibrogenesis Marker PRO-C3 Is Higher in Advanced Liver Fibrosis and Improves in Patients Undergoing Bariatric Surgery

CONTEXT

Serum propeptides of type III and type VI collagen (PRO-C3 and PRO-C6) are elevated in advanced nonalcoholic fatty liver disease (NAFLD), but their value in patients with severe obesity and their evolution after bariatric surgery (BS) is unknown. It is unclear if these markers of fibrogenesis are affected by adipose tissue fibrosis (ATF).

OBJECTIVE

We studied the association of PRO-C3 and PRO-C6 with liver fibrosis before BS, examined their evolution after BS, and evaluated how much patients' ATF contribute to their levels.

METHODS

Serum PRO-C3 and PRO-C6 were measured in 158 BS patients and compared with liver, subcutaneous, and omental adipose tissue histology obtained during surgery. PRO-C3 and PRO-C6 levels of 63 patients were determined in follow-up at 3 and 12 months post-BS.

RESULTS

Patients in the highest quartile of PRO-C3 had a higher risk of advanced liver fibrosis (stage F3-4; odds ratio 5.8; 95% CI [1.5-29.9]; P = 0.017) vs the lowest quartile (adjustment for age, gender, and BMI). PRO-C3 was positively correlated with markers of insulin resistance and liver enzymes. After BS, PRO-C3 levels decreased in patients with high baseline liver fibrosis. This decrease correlated with improvement of metabolic and liver parameters. PRO-C6 was not related to stage of liver fibrosis. ATF did not correlate with PRO-C3 or PRO-C6 levels at baseline or after BS.

CONCLUSION

PRO-C3 was associated with advanced liver fibrosis in patients with severe obesity, and decreased after BS, without being affected by ATF. These data suggest that BS prominently eliminates drivers of hepatic fibrogenesis in NAFLD.

Intermittent Hypoxia Rewires the Liver Transcriptome and Fires up Fatty Acids Usage for Mitochondrial Respiration

Sleep Apnea Syndrome (SAS) is one of the most common chronic diseases, affecting nearly one billion people worldwide. The repetitive occurrence of abnormal respiratory events generates cyclical desaturation-reoxygenation sequences known as intermittent hypoxia (IH). Among SAS metabolic sequelae, it has been established by experimental and clinical studies that SAS is an independent risk factor for the development and progression of non-alcoholic fatty liver disease (NAFLD). The principal goal of this study was to decrypt the molecular mechanisms at the onset of IH-mediated liver injury. To address this question, we used a unique mouse model of SAS exposed to IH, employed unbiased high-throughput transcriptomics and computed network analysis. This led us to examine hepatic mitochondrial ultrastructure and function using electron microscopy, high-resolution respirometry and flux analysis in isolated mitochondria. Transcriptomics and network analysis revealed that IH reprograms Nuclear Respiratory Factor- (NRF-) dependent gene expression and showed that mitochondria play a central role. We thus demonstrated that IH boosts the oxidative capacity from fatty acids of liver mitochondria. Lastly, the unbalance between oxidative stress and antioxidant defense is tied to an increase in hepatic ROS production and DNA damage during IH. We provide a comprehensive analysis of liver metabolism during IH and reveal the key role of the mitochondria at the origin of development of liver disease. These findings contribute to the understanding of the mechanisms underlying NAFLD development and progression during SAS and provide a rationale for novel therapeutic targets and biomarker discovery.

[new recommandation for medical and surgical care of obesity]

TOWARDS NEW RECOMMANDATIONS The french NICE has produced a document describing the current limits to the optimal care of obesity, in particular concerning bariatric surgery. This document also states the perspectives and work that needs to be undergone to improve obesity care. Since october 2020, a working group appointed by the French NICE is writing the clinical recommandations for obesity care in 2nd and 3rd care referral, addressing both the medical and surgical care of obesity. This work has known some delay mainly due to the several waves of COVID-19.

Altered subcutaneous adipose tissue parameters after switching ART-controlled HIV+ patients to raltegravir/maraviroc

OBJECTIVE

To evaluate the effect on anthropometric, metabolic and adipose tissue parameters of switching ART-controlled persons living with HIV (PLWH) from a protease inhibitor regimen to raltegravir/maraviroc.

DESIGN

Sub-study of the ANRS157 ROCnRAL study with the investigation of subcutaneous abdominal adipose tissue (SCAT) biopsy at inclusion and study end.

METHODS

We performed lipoaspiration of paired SCAT samples, histology on fresh/fixed samples and examined the transcriptomic profile analyzed using Illumina microarrays after RNA extraction. Statistical analyses used the Wilcoxon-paired test.

RESULTS

The patients (n = 8) were mainly male (7/8), aged (mean ± standard error of the mean) 54.9 ± 1.2 years, BMI 26.1 ± 1.2 kg/m2, CD4+ 699 ± 56 cells/mm3, all viral load (VL) <50 copies/ml. After a follow-up of 6 ± 0.5 months, all PLWH remained with VL <50 copies/ml. BMI, trunk and limb fat amounts were unchanged yet systemic insulin resistance increased. Adipose tissue histology was unchanged except for borderline increased adipocyte diameter (P = 0.1). Among the 16 094 RNA transcripts, 458 genes were up-regulated and 244 were down-regulated. Analyses of the Kyoto Encyclopedia of Genes and Genomes and Gene Ontology databases, evaluating modifications in the main functional pathways, revealed that genes related to immune recognition/function were less expressed as were genes encoding T-cell receptor and receptor signaling pathways. The gene expression profiles indicated decreased inflammation but genes involved in adipogenesis and insulin resistance were overexpressed.

CONCLUSION

After 6 months of raltegravir/maraviroc, adipogenesis-related gene profile was enhanced in SCAT, in agreement with a tendency for increased adipocyte size. Enhanced SCAT insulin resistance-related profile was concordant with higher systemic insulin resistance. However, the immune activation/inflammation profile was globally lowered. We propose that raltegravir/maraviroc might favor SCAT gain but reduce inflammation/immune activation.

Adipose tissue fibrosis assessed by high resolution ex vivo MRI as a hallmark of tissue alteration in morbid obesity

To determine whether magnetic resonance imaging (MRI) when used in an optimal ex vivo setting can help detecting and quantifying the 3D fibrosis fraction in human subcutaneous adipose tissue (SAT) samples, as compared to histology. This prospective observational study was approved by our institutional review board 3D MRI acquisitions were performed at 4.0 T (Bruker) on XX human SAT samples (around 1 cm3) collected from biopsy in morbidly obese patients. Such acquisitions included saturation-recovery T1 mapping (spatial resolution: 200 µm, acquisition time: ~16 minutes) and DIXON imaging (spatial resolution: 200 µm, acquisition time: ~20 minutes). After MRI, histological quantification of fibrosis was performed using picrosirius staining. T1 maps were clustered based on a k-means algorithm allowing quantification of fibrosis within the adipose tissue and percentage of fibrosis over the entire sample volume was calculated. Fat maps were computed from DIXON in-phase and out-of-phase images. The 3D MRI fibrosis percentage within the SAT samples were comprised between 6% and 15%. Excellent correlations and levels of agreement were observed between single slice MRI and histology (r=0.9, P=0.08) and between 3D MRI and histology in terms fibrosis percentages within SAT samples (r=0.9, P=0.01). High Field ex vivo MRI was able to quantify fibrosis in human SAT samples with high agreement with histology and moreover to provide 3D SAT fibrosis quantification avoiding histological sampling errors.

Abdominal adipose tissue components quantification in MRI as a relevant biomarker of metabolic profile

INTRODUCTION

Abnormal accumulation of adipose tissue (AT) alters the metabolic profile and underlies cardiovascular complications. Conventional measures provide global measurements for the entire body. The purpose of this study was to propose a new approach to quantify the amount and type of truncal AT automatically from MRI in metabolic patients and controls.

MATERIALS AND METHODS

DIXON acquisitions were performed at 1.5 T in 30 metabolic syndrome (MS) (59 ± 6 years), 12 obese (50 ± 11 years), 35 type 2 diabetes (T2DM) patients (56 ± 11 years) and 19 controls (52 ± 11 years). AT was segmented into: subcutaneous AT "SAT", visceral AT "VAT", deep VAT "dVAT", peri-organ VAT "pVAT" using active contours and k-means clustering algorithms. Subsequently, organ AT infiltration index "oVAT" was calculated as the normalized fat signal magnitude in organs.

RESULTS

Excellent intra- and inter-operator reproducibility was obtained for AT segmentation. MS and obese patients had the highest amount of total AT. SAT increased in MS (1144 ± 621 g) and T2DM patients (1024 ± 634 g), and twice the level of SAT in controls (505 ± 238 g), and further increased in obese patients (1429 ± 621 g). While VAT, pVAT and dVAT increased to a similar degree in the metabolic patients compared to controls, the oVAT index was able to differentiate controls from MS and T2DM patients and to discriminate the three metabolic patient groups (p < 0.01). Local AT sub-types were not related to BMI in all groups except for SAT in controls (p = 0.03).

CONCLUSION

Reproducible truncal AT sub-types quantification using 3D MRI was able to characterize patients with metabolic diseases. It may serve in the future as a non-invasive predictor of cardiovascular complications in such patients.

Diagnostic approach to sleep disordered-breathing among patients with grade III obesity

Sleep apnea test (SAT) is a cost-effective approach to evaluate subjects without associated comorbidities suspected for obstructive sleep apnea (OSA), a disorder particularly common in obese subjects. The association of obesity with awake hypercapnia (carbon dioxide arterial pressure, PaCO₂ ≥45 mmHg) defines the obesity-hypoventilation syndrome (OHS), which in turn results in increased morbidity and mortality compared to simple OSA. Isolated hypoventilation during sleep in obese patients (obesity-related sleep hypoventilation, ORSH) is now considered as an early stage of OHS. The aim of this study was to assess the performance of SAT in diagnosing OSA and predicting the presence of ORHS among patients with grade III obesity without awake hypercapnia.

METHODS

Over a 14-months period, patients with grade III obesity (body mass index≥40 kg/m²) presenting moderate-to-severe OSA (apnea-hypopnea index [AHI]≥15) upon SAT and normal awake PaCO₂ at arterial blood gas analysis, systematically underwent in-lab nocturnal polysomnography combined with transcutaneous carbon dioxide pressure (PtcCO₂) monitoring.

RESULTS

Among 48 patients included in the study, 16 (33%) presented an AHI<15 upon polysomnography and 14 (29%) had ORSH. The test revealed no difference in ORSH prevalence between patients with AHI <15 or ≥15 (31% vs. 25%). No SAT variables were independently associated with increased PtCO₂.

CONCLUSIONS

This study shows that SAT overestimates OSA severity and ORSH affects one third of patients with grade III obesity without awake hypercapnia and with moderate-to-severe OSA at SAT, suggesting how polysomnography combined with PtCO₂ monitoring is the most appropriate diagnostic approach for OSA and ORSH in this population.

Decision Tree for the Performance of Intraoperative Liver Biopsy During Bariatric Surgery

BACKGROUND AND AIMS

Bariatric surgery provides a useful opportunity to perform intraoperative liver biopsy to screen for non-alcoholic steatohepatitis (NASH). There is currently no consensus on whether intraoperative liver biopsy should be systematically performed. The aim of this study was to develop and validate a decision tree to guide that choice.

APPROACH AND RESULTS

This prospective study included 102 consecutive patients from the severe obesity outcome network (SOON) cohort in whom liver biopsy was systematically performed during bariatric surgery. A classification and regression tree (CART) was created to identify the nodes that best classified patients with and without NASH. External validation was performed. Seventy-one biopsies were of sufficient quality for analysis (median body mass index 43.3 [40.7; 48.0] kg/m²). NASH was diagnosed in 32.4% of cases. None of the patients with no steatosis on ultrasound had NASH. The only CART node that differentiated between a "high-risk" and a "low-risk" of NASH was alanine aminotransferase (ALT). ALT>53IU/L predicted NASH with a positive predictive value (PPV) of 68% and a negative predictive value (NPP) of 89%, a sensitivity of 77%, and a specificity of 84%. In the external cohort (n=258), PPV was 68%, NPV was 62%, sensitivity was 27%, and specificity was 90%.

CONCLUSIONS

The present work supports intraoperative liver biopsy to screen for NASH in patients with ALT>53IU/L; however, patients with no steatosis on ultrasound should not undergo biopsy. The CART failed to identify an algorithm with a good sensitivity to screen for NASH in patients with ultrasonography-proven steatosis and ALT≤53IU/L.

Resting-state connectivity within the brain's reward system predicts weight loss and correlates with leptin

Weight gain is often associated with the pleasure of eating food rich in calories. This idea is based on the findings that people with obesity showed increased neural activity in the reward and motivation systems of the brain in response to food cues. Such correlations, however, overlook the possibility that obesity may be associated with a metabolic state that impacts the functioning of reward and motivation systems, which in turn could be linked to reactivity to food and eating behaviour and weight gain. In a study involving 44 female participants [14 patients with obesity, aged 20–63 years (mean: 42, SEM: 3.2 years), and 30 matched lean controls, aged 22–60 years (mean: 37, SEM: 1.8 years)], we investigated how ventromedial prefrontal cortex seed-to-voxel resting-state connectivity distinguished between lean and obese participants at baseline. We used the results of this first step of our analyses to examine whether changes in ventromedial prefrontal cortex resting-state connectivity over 8 months could formally predict weight gain or loss. It is important to note that participants with obesity underwent bariatric surgery at the beginning of our investigation period. We found that ventromedial prefrontal cortex–ventral striatum resting-state connectivity and ventromedial–dorsolateral prefrontal cortex resting-state connectivity were sensitive to obesity at baseline. However, only the ventromedial prefrontal cortex–ventral striatum resting-state connectivity predicted weight changes over time using cross-validation, out-of-sample prediction analysis. Such an out-of-sample prediction analysis uses the data of all participants of a training set to predict the actually observed data in one independent participant in the hold-out validation sample and is then repeated for all participants. In seeking to explain the reason why ventromedial pre-frontal cortex–ventral striatum resting-state connectivity as the central hub of the brain’s reward and motivational system may predict weight change over time, we linked weight loss surgery-induced changes in ventromedial prefrontal cortex–ventral striatum resting-state connectivity to surgery-induced changes in homeostatic hormone regulation. More specifically, we focussed on changes in fasting state systemic leptin, a homeostatic hormone signalling satiety, and inhibiting reward-related dopamine signalling. We found that the surgery-induced increase in ventromedial prefrontal cortex–ventral striatum resting-state connectivity was correlated with a decrease in fasting-state systemic leptin. These findings establish the first link between individual differences in brain connectivity in reward circuits in a more tonic state at rest, weight change over time and homeostatic hormone regulation.

COVID-19 and its Severity in Bariatric Surgery-Operated Patients

OBJECTIVE

Obesity is a major risk factor for severe forms of coronavirus disease (COVID-19), but little is known about the post-bariatric surgery (BS) setting. The prevalence of likely COVID-19 and its risk factors in patients followed up after BS was assessed.

METHODS

A total of 738 patients who underwent BS and were followed up at a university medical center were surveyed. A retrospective comparison of characteristics at baseline, 1 year after BS, and at the time of lockdown was performed between patients with COVID-19-likely events (CL) based on a combination of reported symptoms and those for whom COVID-19 was unlikely.

RESULTS

CL occurred in 62 (8.4%) patients, among whom 4 (6.4%) had a severe form requiring hospitalization and 1 (1.6%) died. The CL group had a higher proportion of persistent type 2 diabetes (T2D) at last follow-up (36.2% vs. 20.3%, P = 0.01). BMI at the time of lockdown was lower in the CL group (30.2 ± 5.1 vs. 32.8 ± 6.5 kg/m² ; P < 0.01) with higher percent weight loss since BS in the CL group. Severe forms of COVID-19 requiring hospitalization were associated with persistent T2D at the last follow-up visit.

CONCLUSIONS

In BS patients, CL were associated with persistent T2D and lower BMI.

Senescence-associated β-galactosidase in subcutaneous adipose tissue associates with altered glycaemic status and truncal fat in severe obesity

AIM/HYPOTHESIS

Altered adipose tissue secretory profile contributes to insulin resistance and type 2 diabetes in obesity. Preclinical studies have identified senescent cells as a cellular source of proinflammatory factors in adipose tissue of obese mice. In humans, potential links with obesity comorbidities are poorly defined. Here, we investigated adipose tissue senescent status and relationships with metabolic complications in human obesity.

METHODS

The study includes a prospective cohort of 227 individuals with severe obesity. A photometric method was used to quantify senescence-associated β-galactosidase (SA-β-gal) activity in paired subcutaneous and omental adipose tissue biopsies obtained during gastric surgery. Gene and secretory profiling was performed in adipose tissue biopsies and in human primary pre-adipocytes in the presence or absence of senolytic drugs targeting senescent cells. Participants were phenotyped for anthropometric and bioclinical variables, metabolic complications and gastric surgery-induced improvement to address relationships with adipose tissue SA-β-gal.

RESULTS

SA-β-gal activity was sevenfold higher in subcutaneous than in omental adipose tissue and not associated with BMI or chronological age. Several factors, including insulin-like growth factor binding protein 3 (IGFBP3), plasminogen activator inhibitor 1 (PAI1), C-C motif chemokine ligand 2 (CCL2) and IL-6, were upregulated in subcutaneous adipose tissue in relation with SA-β-gal (p for linear trend across tertiles <0.05) and in pre-adipocytes cultured with inflammatory macrophage conditioned media. Senolytic treatment reduced SA-β-gal staining and normalised these alterations. In the whole population, subcutaneous adipose tissue SA-β-gal activity was positively associated with serum leptin, markers of insulin resistance and increased trunk fat mass. Metabolic complications, including type 2 diabetes and dyslipidaemia, were more prevalent in patients with high levels of SA-β-gal, but improved with bariatric surgery whatever the initial adipose tissue senescent status.

CONCLUSIONS/INTERPRETATION

This study highlights a phenotype of senescence in adipose tissue of severely obese individuals, which characterises prominently subcutaneous fat depots. Subcutaneous adipose tissue senescence is significantly linked to altered glucose metabolism and body fat distribution. Elimination of senescent cells through senolytic treatment could alleviate metabolic complications in severely obese people. Graphical abstract.

Metabolism and Metabolic Disorders and the Microbiome: The Intestinal Microbiota Associated With Obesity, Lipid Metabolism, and Metabolic Health-Pathophysiology and Therapeutic Strategies

Changes in the intestinal microbiome have been associated with obesity and type 2 diabetes, in epidemiological studies and studies of the effects of fecal transfer in germ-free mice. We review the mechanisms by which alterations in the intestinal microbiome contribute to development of metabolic diseases, and recent advances, such as the effects of the microbiome on lipid metabolism. Strategies have been developed to modify the intestinal microbiome and reverse metabolic alterations, which might be used as therapies. We discuss approaches that have shown effects in mouse models of obesity and metabolic disorders, and how these might be translated to humans to improve metabolic health.

Imidazole propionate is increased in diabetes and associated with dietary patterns and altered microbial ecology

Microbiota-host-diet interactions contribute to the development of metabolic diseases. Imidazole propionate is a novel microbially produced metabolite from histidine, which impairs glucose metabolism. Here, we show that subjects with prediabetes and diabetes in the MetaCardis cohort from three European countries have elevated serum imidazole propionate levels. Furthermore, imidazole propionate levels were increased in subjects with low bacterial gene richness and Bacteroides 2 enterotype, which have previously been associated with obesity. The Bacteroides 2 enterotype was also associated with increased abundance of the genes involved in imidazole propionate biosynthesis from dietary histidine. Since patients and controls did not differ in their histidine dietary intake, the elevated levels of imidazole propionate in type 2 diabetes likely reflects altered microbial metabolism of histidine, rather than histidine intake per se. Thus the microbiota may contribute to type 2 diabetes by generating imidazole propionate that can modulate host inflammation and metabolism.

Gut microbial metabolism of nutrients contributes to metabolic diseases, and the histidine metabolite imidazole propionate (ImP) is produced by type 2 diabetes (T2D) associated microbiome. Here the authors report that circulating ImP levels are increased in subjects with prediabetes or T2D in three European populations, and this increase associates with altered gut microbiota rather than dietary histidine.

Gut microbiota of obese subjects with Prader-Willi syndrome is linked to metabolic health

OBJECTIVE

The gut microbiota has been implicated in the aetiology of obesity and associated comorbidities. Patients with Prader-Willi syndrome (PWS) are obese but partly protected against insulin resistance. We hypothesised that the gut microbiota of PWS patients differs from that of non-genetically obese controls and correlate to metabolic health. Therefore, here we used PWS as a model to study the role of gut microbiota in the prevention of metabolic complications linked to obesity.

DESIGN

We conducted a case-control study with 17 adult PWS patients and 17 obese subjects matched for body fat mass index, gender and age. The subjects were metabolically characterised and faecal microbiota was profiled by 16S ribosomal RNA gene sequencing. The patients' parents were used as a non-obese control group. Stool samples from two PWS patients and two obese controls were used for faecal microbiota transplantations in germ-free mice to examine the impact of the microbiota on glucose metabolism.

RESULTS

The composition of the faecal microbiota in patients with PWS differed from that of obese controls, and was characterised by higher phylogenetic diversity and increased abundance of several taxa such as Akkermansia, Desulfovibrio and Archaea, and decreased abundance of Dorea. Microbial taxa prevalent in the PWS microbiota were associated with markers of insulin sensitivity. Improved insulin resistance of PWS was partly transmitted by faecal microbiota transplantations into germ-free mice.

CONCLUSION

The gut microbiota of PWS patients is similar to that of their non-obese parents and might play a role for the protection of PWS patients from metabolic complications.

Cholangiocarcinoma Following Bariatric Surgery: a Prospective Follow-Up Single-Center Audit

BACKGROUND

Cholangiocarcinoma (CC) incidence is rising worldwide. Obesity and its related metabolic impairments are associated with primitive liver malignancies including CC. While bariatric surgery (BS) is associated with decreased risk of incident cancer, few data are available regarding CC incidence, presentation, and management issues after BS.

METHODS

We retrospectively reviewed collected data on 1911 consecutive patients undergoing BS from 2010 to 2019.

RESULTS

We recorded three cases (0.16%) of CC during the postoperative follow-up. All cases underwent a Roux-en-Y gastric bypass (RYGB) for class III obesity with metabolic diseases (i.e., type 2 diabetes mellitus, hypertension, dyslipidemia, and obstructive sleep apnea) without any personal or familial history of biliary disease. The patients presented with an inaugural jaundice or pruritus at 8, 12, and 13 months after RYBG, which enabled the diagnosis of metastatic CCs in all cases. In such palliative setting without access to the pancreato-biliary system, biliary drainage was ensured by a percutaneous trans-hepatic biliary drain. Chemotherapy was initiated in two patients. All the patients died within a delay of 2, 11, and 17 months after the diagnosis, respectively.

CONCLUSION

The incidence of post-BS CC appears low, but the prognosis is poor because of advanced stages at diagnosis. These cases illustrate the difficulty to make both on-time diagnosis and optimal management of CC especially in patients operated of RYGB with limited access to the excluded anatomy.

Nonalcoholic Fatty Liver Disease: Modulating Gut Microbiota to Improve Severity?

Gut microbiota plays a role in the pathophysiology of metabolic diseases, which include nonalcoholic fatty liver diseases, through the gut-liver axis. To date, clinical guidelines recommend a weight loss goal of 7%-10% to improve features of nonalcoholic fatty liver diseases. Because this target is not easily achieved by all patients, alternative therapeutic options are currently being evaluated. This review focuses on therapeutics that aim to modulate the gut microbiota and the gut-liver axis. We discuss how probiotics, prebiotics, synbiotic, fecal microbiota transfer, polyphenols, specific diets, and exercise interventions have been found to modify gut microbiota signatures; improve nonalcoholic fatty liver disease outcomes; and detail, when available, the different mechanisms by which these beneficial outcomes might occur. Apart from probiotics that have already been tested in human randomized controlled trials, most of these potential therapeutics have been studied in animals. Their efficacy still warrants confirmation in humans using appropriate design.

Prediction of Long-Term Diabetes Remission After RYGB, Sleeve Gastrectomy, and Adjustable Gastric Banding Using DiaRem and Advanced-DiaRem Scores

PURPOSE

DiaRem is a clinical scoring system designed to predict diabetes remission (DR) 1-year post-Roux-en-Y gastric bypass (RYGB). We examined long-term (2- and 5-year) postoperative DR prediction by DiaRem and an advanced-DiaRem (Ad-DiaRem) score following RYGB, sleeve gastrectomy (SG), and gastric banding (GB).

METHODS

We accessed data from a computerized database of persons with type 2 diabetes and BMI ≥ 30 kg/m² who underwent RYGB, SG, or GB, and determined DR status 2- and 5-year postoperative according to preoperative DiaRem and the Ad-DiaRem calculated scores.

RESULTS

Among 1459 patients with 5-year postoperative diabetes status data, 53.6% exhibited DR. For RYGB, Ad-DiaRem trended to exhibit mildly improved predictive capacity 5-year postoperatively compared to DiaRem: Areas under receiver operating characteristic [AUROC] curves were 0.85 (0.76-0.93) and 0.78 (0.69-0.88), respectively. The positive predictive values (PPVs) detecting > 80% of those achieving DR (i.e., sensitivity ≥ 0.8) were 78.2% and 73.2%, respectively, and higher Ad-DiaRem scores more consistently associated with decreased DR rates. Following SG, both scores had an AUROC of 0.82, but Ad-DiaRem still had a higher PPV for predicting > 80% of those with 5-year postoperative DR (76.2% and 71.0%). Predictive capacity parameters were comparatively lower, for both scores, when considering DR 5-year post-GB (AUROC: 0.73 for both scores, PPV: 66.3% and 64.3%, respectively).

CONCLUSIONS

Ad-DiaRem provides modest improvement compared to DiaRem in predicting long-term DR 5-years post-RYGB. Both scores similarly provide fair predictive capacity for 5-year postoperative DR after SG.

Gut microbiota composition alterations are associated with the onset of diabetes in kidney transplant recipients

Background

The gut dysbiosis associated with diabetes acquired before or after kidney transplantation (KT) has not been explored.

Gut microbiota: a promising target against cardiometabolic diseases

Introduction: Cardiometabolic diseases (CMD) are a group of interrelated disorders such as metabolic syndrome, type 2 diabetes mellitus and cardiovascular diseases (CVD). As the prevalence of these diseases increases globally, efficient new strategies are necessary to target CMD and modifiable risk factors. In the past decade, evidence has accumulated regarding the influence of gut microbiota (GM) on CMD, providing new targets for therapeutic interventions.Areas covered: This narrative review discusses the pathophysiologic link between CMD, GM, and potential microbiota-based targets against atherosclerosis and modifiable risk factors for atherosclerosis. Low-grade inflammation can be induced through GM and its derived metabolites. CMD are influenced by GM and microbiota-derived metabolites such as short-chain fatty acids (SCFA), secondary bile acids, trimethylamine N-oxide (TMAO), and the composition of GM can modulate host metabolism. All of the above can lead to promising therapeutic targets.Expert opinion: Most data are derived from animal models or human association studies; therefore, more translational and interventional research in humans is necessary to validate these promising findings. Reproduced findings such as aberrant microbiota patterns or circulating biomarkers could be targeted depending on individual metabolic profiles, moving toward personalized medicine in CMD.

A place for vitamin supplementation and functional food in bariatric surgery?

PURPOSE OF REVIEW

This article summarizes recent literature concerning vitamin deficiency and required supplementation post-bariatric surgery, focusing on vitamin D (and associated clinical adverse effect on bone loss) and on the potential implication of the gut microbiota.

RECENT FINDINGS

Bariatric surgery induces weight loss and metabolic improvements yet with major inter-individual variability. If it is efficient in most patients, some display poor response (i.e. patients with the lowest weight loss at 1 year or weight regain afterwards, or patients without metabolic disease remission). Despite systematic vitamin supplementation, some patients develop vitamin deficiencies leading to poor clinical outcomes, among which vitamin D deficiency associated with observed bone mass loss and fractures. Recent mechanistic studies led to understand better the involved physiopathology. Furthermore, different intervention studies tested on top of bariatric surgery (using vitamin, diet, or nutrients acting as functional food) have evaluated whether nutritional adverse outcomes could be improved. Importantly, gut microbiota involved in food digestion and metabolization and vitamin synthesis is largely perturbed during severe obesity and is partially restored post-surgery, yet again with large interindividual variability. Whether differential gut microbiota modification could be associated with vitamin deficiencies is an open question.

SUMMARY

Future clinical research studies will need to evaluate whether add-on intervention to bariatric surgery using vitamin, diet, or specific food items could help prevent nutritional deficiencies and improve clinical response observed post-surgery. Importantly, personalizing the add-on intervention post-surgery upon gut microbiota composition should be tested in predicted poor-responders to surgery as already performed during diet intervention to further improve metabolic health.

The mid-infrared spectroscopy: A novel non-invasive diagnostic tool for NASH diagnosis in severe obesity

There is an urgent medical need to develop non-invasive tests for non-alcoholic steatohepatitis (NASH). This study evaluates the diagnostic performance of an innovative model based on mid-infrared (MIR) spectroscopy for the diagnosis of NASH.

Methods

Severely obese patients who underwent a bariatric procedure at the University Hospital of Nice, France (n = 395) were prospectively recruited. The clinico-biological characteristics were measured prior to surgery. Liver biopsies were collected during the surgical procedure and assessed by a pathologist. A training group (316 patients, NASH: 16.8%) and a validation group (79 patients, NASH: 16.5%) were randomly defined. MIR spectra were acquired by fiber evanescent wave spectroscopy, using chalcogenide glass fiber optic sensors and a spectrometer. This absorption spectroscopic technique delivers a spectrum that identifies the molecular composition of a sample, defining a patient's metabolic fingerprint.

Results

The areas under the receiver operating curve (AUROC) for the diagnosis of NASH were 0.82 and 0.77 in the training and validation groups, respectively. The best threshold was 0.15, which was associated with a sensitivity of 0.75 and 0.69, and a specificity of 0.72 and 0.76. Negative predictive values of 0.94 and 0.93 and positive predictive values of 0.35 and 0.36, as well as correctly classified patient rates of 72% and 75% were obtained in the training and validation groups, respectively. A composite model using aspartate aminotransferase level, triglyceride level and waist circumference alongside the MIR spectra led to an increase in AUROC (0.88 and 0.84 for the training and validations groups, respectively).

Conclusions

MIR spectroscopy provides good sensitivity and negative predictive values for NASH screening in patients with severe obesity.

Lay summary

There is an urgent need for tools to non-invasively diagnose and monitor non-alcoholic steatohepatitis (NASH). This study evaluates the performance of a new tool for fast NASH diagnosis based on mid-infrared (MIR) spectroscopy. Using serum samples from severely obese patients who underwent a bariatric procedure, which enabled a concomitant liver biopsy to be performed, the MIR spectroscopy model performed well in screening patients for NASH compared to a traditional, histological diagnosis.

•

There is no validated non-invasive diagnostic tool for NASH in routine care.

•

NASH follow-up requires a non-invasive diagnostic method.

•

Using a simple drop of serum, the mid-infrared spectrum captures a patient’s metabolic fingerprint.

•

A model based on mid-infrared spectroscopy provides efficient NASH screening for patients with severe obesity.

Elevated serum ceramides are linked with obesity-associated gut dysbiosis and impaired glucose metabolism

INTRODUCTION

Low gut microbiome richness is associated with dyslipidemia and insulin resistance, and ceramides and other sphingolipids are implicated in the development of diabetes.

OBJECTIVES

Determine whether circulating sphingolipids, particularly ceramides, are associated with alterations in the gut microbiome among obese patients with increased diabetes risk.

METHODS

This was a cross-sectional and longitudinal retrospective analysis of a dietary/weight loss intervention. Fasted serum was collected from 49 participants (41 women) and analyzed by HPLC-MS/MS to quantify 45 sphingolipids. Shotgun metagenomic sequencing of stool was performed to profile the gut microbiome.

RESULTS

Confirming the link to deteriorated glucose homeostasis, serum ceramides were positively correlated with fasting glucose, but inversely correlated with fasting and OGTT-derived measures of insulin sensitivity and β-cell function. Significant associations with gut dysbiosis were demonstrated, with SM and ceramides being inversely correlated with gene richness. Ceramides with fatty acid chain lengths of 20-24 carbons were the most associated with low richness. Diet-induced weight loss, which improved gene richness, decreased most sphingolipids. Thirty-one MGS, mostly corresponding to unidentified bacteria species, were inversely correlated with ceramides, including a number of Bifidobacterium and Methanobrevibacter smithii. Higher ceramide levels were also associated with increased metagenomic modules for lipopolysaccharide synthesis and flagellan synthesis, two pathogen-associated molecular patterns, and decreased enrichment of genes involved in methanogenesis and bile acid metabolism.

CONCLUSION

This study identifies an association between gut microbiota richness, ceramides, and diabetes risk in overweight/obese humans, and suggests that the gut microbiota may contribute to dysregulation of lipid metabolism in metabolic disorders.

Gut Microbiota Dysbiosis in Human Obesity: Impact of Bariatric Surgery

PURPOSE OF REVIEW

In this review, we summarize what is currently described in terms of gut microbiota (GM) dysbiosis modification post-bariatric surgery (BS) and their link with BS-induced clinical improvement. We also discuss how the major inter-individual variability in terms of GM changes could impact the clinical improvements seen in patients.

RECENT FINDINGS

The persisting increase in severe obesity prevalence has led to the subsequent burst in BS number. Indeed, it is to date the best treatment option to induce major and sustainable weight loss and metabolic improvement in these patients. During obesity, the gut microbiota displays distinctive features such as low microbial gene richness and compositional and functional alterations (termed dysbiosis) which have been associated with low-grade inflammation, increased body weight and fat mass, as well as type-2 diabetes. Interestingly, GM changes post-BS is currently being proposed as one the many mechanism explaining BS beneficial clinical outcomes. BS enables partial rescue of GM dysbiosis observed during obesity. Some of the GM characteristics modified post-BS (composition in terms of bacteria and functions) are linked to BS beneficial outcomes such as weight loss or metabolic improvements. Nevertheless, the changes in GM post-BS display major variability from one patient to the other. As such, further large sample size studies associated with GM transfer studies in animals are still needed to completely decipher the role of GM in the clinical improvements observed post-surgery.

Akkermansia muciniphila abundance is lower in severe obesity, but its increased level after bariatric surgery is not associated with metabolic health improvement

The gut bacterial species Akkermansia muciniphila is associated with a healthier clinical profile. The purpose of this study was to determine the association between A. muciniphila and glucose homeostasis in patients undergoing bariatric surgery (BS): gastric banding (GB) or Roux-en-Y gastric bypass (RYGB). This nonrandomized prospective study included 65 women with severe obesity. Longitudinal analysis included subjects for whom A. muciniphila data were available at follow-up [1, 3, and 12 mo; GB (n = 10) or RYGB (n = 11)]. Glucose homeostasis markers were measured under fasting conditions (glucose, insulin, and HbA1c) or during an oral glucose tolerance test. Fecal microbiota was analyzed using shotgun metagenomics, and A. muciniphila relative abundance was assessed with 16S rRNA quantitative PCR. A. muciniphila relative abundance was significantly lower in severe obesity [mean body mass index, 45.7 kg/m² (SD 5.4)] than in moderate obesity [33.2 kg/m² (SD 3.8)] but not associated with glucose homeostasis markers. A significant increase in A. muciniphila relative abundance after RYGB was not correlated with metabolic improvement. Baseline A. muciniphila abundance was correlated with bacterial gene richness and was highest in the high-richness Ruminococcaceae enterotype. A. muciniphila increased in relative abundance after BS in patients with low baseline A. muciniphila abundance, especially those with a Bacteroides type 2 enterotype classification. Although decreased in severe obesity, relative abundance of A. muciniphila was not associated with glucose homeostasis before or after BS. A certain level of A. muciniphila abundance might be required to observe a beneficial link to health. The severity of obesity and gut dysbiosis may partly explain the discrepancy with previous findings in less obese populations.

Fecal Microbiota Transplantation: a Future Therapeutic Option for Obesity/Diabetes?

PURPOSE OF REVIEW

The aim of this review is to summarize the current data available on the metabolic effects of fecal microbiota transplantation (FMT) including obesity and glucose metabolism in humans.

RECENT FINDINGS

Gut microbiota dysbiosis is a frequent characteristic observed in obesity and related metabolic diseases. Pieces of evidence mostly generated in mouse models suggest that rescuing this dysbiosis associates with improved metabolism. In humans, dietary or bariatric surgery interventions are often accompanied by complete or partial restoration of this dysbiosis together with weight reduction and metabolic amelioration. FMT is an interesting option to modify gut microbiota and has been associated with improved clinical outcomes, albeit only used in routine care for Clostridium difficile infection. However, there are only limited data on using FMT in the metabolic context. FMT from lean donors significantly improves insulin sensitivity in obese subjects with metabolic syndrome. However, there is a wide range of clinical responses. Interestingly in subjects with high microbial gene richness at baseline and when FMT donors that are metabolically compromised are used, no metabolic improvement is seen. Moreover, more studies evaluating the effect of FMT in patients with overt type 2 diabetes are warranted. Furthermore, interventions (in the receiver prior to FMT) aiming to enhance FMT response also need evaluation.

A Data Integration Multi-Omics Approach to Study Calorie Restriction-Induced Changes in Insulin Sensitivity

Background: The mechanisms responsible for calorie restriction (CR)-induced improvement in insulin sensitivity (IS) have not been fully elucidated. Greater insight can be achieved through deep biological phenotyping of subjects undergoing CR, and integration of big data. Materials and Methods: An integrative approach was applied to investigate associations between change in IS and factors from host, microbiota, and lifestyle after a 6-week CR period in 27 overweight or obese adults (ClinicalTrials.gov: NCT01314690). Partial least squares regression was used to determine associations of change (week 6 - baseline) between IS markers and lifestyle factors (diet and physical activity), subcutaneous adipose tissue (sAT) gene expression, metabolomics of serum, urine and feces, and gut microbiota composition. ScaleNet, a network learning approach based on spectral consensus strategy (SCS, developed by us) was used for reconstruction of biological networks. Results: A spectrum of variables from lifestyle factors (10 nutrients), gut microbiota (10 metagenomics species), and host multi-omics (metabolic features: 84 from serum, 73 from urine, and 131 from feces; and 257 sAT gene probes) most associated with IS were identified. Biological network reconstruction using SCS, highlighted links between changes in IS, serum branched chain amino acids, sAT genes involved in endoplasmic reticulum stress and ubiquitination, and gut metagenomic species (MGS). Linear regression analysis to model how changes of select variables over the CR period contribute to changes in IS, showed greatest contributions from gut MGS and fiber intake. Conclusion: This work has enhanced previous knowledge on links between host glucose homeostasis, lifestyle factors and the gut microbiota, and has identified potential biomarkers that may be used in future studies to predict and improve individual response to weight-loss interventions. Furthermore, this is the first study showing integration of the wide range of data presented herein, identifying 115 variables of interest with respect to IS from the initial input, consisting of 9,986 variables. Clinical Trial Registration: clinicaltrials.gov (NCT01314690).

Comparative Evaluation of Microbiota Engraftment Following Fecal Microbiota Transfer in Mice Models: Age, Kinetic and Microbial Status Matter

The intestinal microbiota and its functions are intricately interwoven with host physiology. Colonizing rodents with donor microbiota provides insights into host-microbiota interactions characterization and the understanding of disease physiopathology. However, a better assessment of inoculation methods and recipient mouse models is needed. Here, we compare the engraftment at short and long term of genetically obese mice microbiota in germ-free (GF) mice and juvenile and adult specific pathogen free (SPF) mice. We also tested the effects of initial microbiota depletion before microbiota transfer. In the present work, donor microbiota engraftment was better in juvenile SPF mice than in adult SPF mice. In juvenile mice, initial microbiota depletion using laxatives or antibiotics improved donor microbiota engraftment 9 weeks but not 3 weeks after microbiota transfer. Microbiota-depleted juvenile mice performed better than GF mice 3 weeks after the microbiota transfer. However, 9 weeks after transfer, colonized GF mice microbiota had the lowest Unifrac distance to the donor microbiota. Colonized GF mice were also characterized by a chronic alteration in intestinal absorptive function. With these collective results, we show that the use of juvenile mice subjected to initial microbiota depletion constitutes a valid alternative to GF mice in microbiota transfer studies.

Major microbiota dysbiosis in severe obesity: fate after bariatric surgery

OBJECTIVES

Decreased gut microbial gene richness (MGR) and compositional changes are associated with adverse metabolism in overweight or moderate obesity, but lack characterisation in severe obesity. Bariatric surgery (BS) improves metabolism and inflammation in severe obesity and is associated with gut microbiota modifications. Here, we characterised severe obesity-associated dysbiosis (ie, MGR, microbiota composition and functional characteristics) and assessed whether BS would rescue these changes.

DESIGN

Sixty-one severely obese subjects, candidates for adjustable gastric banding (AGB, n=20) or Roux-en-Y-gastric bypass (RYGB, n=41), were enrolled. Twenty-four subjects were followed at 1, 3 and 12 months post-BS. Gut microbiota and serum metabolome were analysed using shotgun metagenomics and liquid chromatography mass spectrometry (LC-MS). Confirmation groups were included.

RESULTS

Low gene richness (LGC) was present in 75% of patients and correlated with increased trunk-fat mass and comorbidities (type 2 diabetes, hypertension and severity). Seventy-eight metagenomic species were altered with LGC, among which 50% were associated with adverse body composition and metabolic phenotypes. Nine serum metabolites (including glutarate, 3-methoxyphenylacetic acid and L-histidine) and functional modules containing protein families involved in their metabolism were strongly associated with low MGR. BS increased MGR 1 year postsurgery, but most RYGB patients remained with low MGR 1 year post-BS, despite greater metabolic improvement than AGB patients.

CONCLUSIONS

We identified major gut microbiota alterations in severe obesity, which include decreased MGR and related functional pathways linked with metabolic deteriorations. The lack of full rescue post-BS calls for additional strategies to improve the gut microbiota ecosystem and microbiome-host interactions in severe obesity.

TRIAL REGISTRATION NUMBER

NCT01454232.

Long-term Relapse of Type 2 Diabetes After Roux-en-Y Gastric Bypass: Prediction and Clinical Relevance

OBJECTIVE

Roux-en-Y gastric bypass (RYGB) induces type 2 diabetes remission (DR) in 60% of patients at 1 year, yet long-term relapse occurs in half of these patients. Scoring methods to predict DR outcomes 1 year after surgery that include only baseline parameters cannot accurately predict 5-year DR (5y-DR). We aimed to develop a new score to better predict 5y-DR.

RESEARCH DESIGN AND METHODS

We retrospectively included 175 RYGB patients with type 2 diabetes with 5-year follow-up. Using machine learning algorithms, we developed a scoring method, 5-year Advanced-Diabetes Remission (5y-Ad-DiaRem), predicting longer-term DR postsurgery by integrating medical history, bioclinical data, and antidiabetic treatments. The scoring method was based on odds ratios and variables significantly different between groups. This score was further validated in three independent RYGB cohorts from three European countries.

RESULTS

Compared with 5y-DR patients, patients who had relapsed after 5 years exhibited more severe type 2 diabetes at baseline, lost significantly less weight during the 1st year after RYGB, and regained more weight afterward. The 5y-Ad-DiaRem includes baseline (diabetes duration, number of antidiabetic treatments, and HbA_1c) and 1-year follow-up parameters (glycemia, number of antidiabetic treatments, remission status, 1st-year weight loss). The 5y-Ad-DiaRem was accurate (area under the receiver operating characteristic curve [AUROC], 90%; accuracy, 85%) at predicting 5y-DR, performed better than the Diabetes Remission score (DiaRem) and the Advanced-DiaRem (AUROC, 81% and 84%; accuracy, 79% and 78%, respectively), and correctly reclassified 13 of 39 patients misclassified with the DiaRem. The 5y-Ad-DiaRem robustness was confirmed in the independent cohorts.

CONCLUSIONS

The 5y-Ad-DiaRem accurately predicts 5y-DR and appears relevant to identify patients at risk for relapse. Using this score could help personalize patient care after the 1st year post-RYGB to maximize weight loss, limit weight regains, and prevent relapse.