A Genetic Risk Score Is Associated with Weight Loss Following Roux-en Y Gastric Bypass Surgery

Use of polygenic risk scores to assess weight loss after bariatric surgery: a 5-year follow-up study

BACKGROUND

Bariatric surgery (BS) is currently the most effective long-term treatment of severe obesity. However, the interindividual variability observed in surgical outcomes suggests a moderating effect of several factors, including individual genetic background. This study aimed to investigate the contribution of the genetic architecture of body mass index (BMI) to the variability in weight loss outcomes after BS.

METHODS

A total of 106 patients with severe obesity who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy were followed up for 5 years. Changes in BMI (BMIchange) and percentage of total weight loss (%TWL) were evaluated during the postoperative period. Polygenic risk scores (PRSs), including 50 genetic variants, were calculated for each participant to determine their genetic risk of high BMI based on a previous genome-wide association study. Generalized estimating equation models were used to study the role of the individual's polygenic score and other factors on BMIchange and %TWL in the long term after surgery.

RESULTS

This study found an effect of the polygenic score on %TWL and BMIchange, in which patients with lower scores had better outcomes after surgery than those with higher scores. Furthermore, when analyzing only patients who underwent RYGB, the results were replicated, showing greater weight loss after surgery for patients with lower polygenic scores.

DISCUSSION

Our results indicate that genetic background assessed with PRSs, along with other individual factors, such as biological sex, age, and preoperative BMI, has an effect on BS outcomes and could represent a useful tool for estimating surgical outcomes in advance.

The AP-2 Family of Transcription Factors-Still Undervalued Regulators in Gastroenterological Disorders

Activating enhancer-binding protein 2 (AP-2) is a family of transcription factors (TFs) that play crucial roles in regulating embryonic and oncogenic development. In addition to splice isoforms, five major family members encoded by the TFAP2A/B/C/D/E genes have been identified in humans, i.e., AP-2α/β/γ/δ/ε. In general, the first three TFs have been studied more thoroughly than AP-2δ or AP-2ε. Currently, there is a relatively limited body of literature focusing on the AP-2 family in the context of gastroenterological research, and a comprehensive overview of the existing knowledge and recommendations for further research directions is lacking. Herein, we have collected available gastroenterological data on AP-2 TFs, discussed the latest medical applications of each family member, and proposed potential future directions. Research on AP-2 in gastrointestinal tumors has predominantly been focused on the two best-described family members, AP-2α and AP-2γ. Surprisingly, research in the past decade has highlighted the importance of AP-2ε in the drug resistance of gastric cancer (GC) and colorectal cancer (CRC). While numerous questions about gastroenterological disorders await elucidation, the available data undoubtedly open avenues for anti-cancer targeted therapy and overcoming chemotherapy resistance. In addition to gastrointestinal cancers, AP-2 family members (primarily AP-2β and marginally AP-2γ) have been associated with other health issues such as obesity, type 2 diabetes, liver dysfunction, and pseudo-obstruction. On the other hand, AP-2δ has been poorly investigated in gastroenterological disorders, necessitating further research to delineate its role. In conclusion, despite the limited attention given to AP-2 in gastroenterology research, pivotal functions of these transcription factors have started to emerge and warrant further exploration in the future.

MTCH2 in Metabolic Diseases, Neurodegenerative Diseases, Cancers, Embryonic Development and Reproduction

Mitochondrial carrier homolog 2 (MTCH2) is a member of the solute carrier 25 family, located on the outer mitochondrial membrane. MTCH2 was first identified in 2000. The development in MTCH2 research is rapidly increasing. The most well-known role of MTCH2 is linking to the pro-apoptosis BID to facilitate mitochondrial apoptosis. Genetic variants in MTCH2 have been investigated for their association with metabolic and neurodegenerative diseases, however, no intervention or therapeutic suggestions were provided. Recent studies revealed the physiological and pathological function of MTCH2 in metabolic diseases, neurodegenerative diseases, cancers, embryonic development and reproduction via regulating mitochondrial apoptosis, metabolic shift between glycolysis and oxidative phosphorylation, mitochondrial fusion/fission, epithelial-mesenchymal transition, etc. This review endeavors to assess a total of 131 published articles to summarise the structure and physiological/pathological role of MTCH2, which has not previously been conducted. This review concludes that MTCH2 plays a crucial role in metabolic diseases, neurodegenerative diseases, cancers, embryonic development and reproduction, and the predominant molecular mechanism is regulation of mitochondrial function. This review gives a comprehensive state of current knowledgement on MTCH2, which will promote the therapeutic research of MTCH2.

Unveiling the connection: Long-chain non-coding RNAs and critical signaling pathways in breast cancer

Breast cancer is a complex and diverse condition that disrupts multiple signaling pathways essential for cell proliferation, survival, and differentiation. Recently, the significant involvement of long-chain non-coding RNAs (lncRNAs) in controlling key signaling pathways associated with breast cancer development has been discovered. This review aims to explore the interaction between lncRNAs and various pathways, including the AKT/PI3K/mTOR, Wnt/β-catenin, Notch, DNA damage response, TGF-β, Hedgehog, and NF-κB signaling pathways, to gain a comprehensive understanding of their roles in breast cancer. The AKT/PI3K/mTOR pathway regulates cell growth, survival, and metabolic function. Recent data suggests that specific lncRNAs can influence the functioning of this pathway, acting as either oncogenes or tumor suppressors. Dysregulation of this pathway is commonly observed in breast cancer cases. Moreover, breast cancer development has been associated with other pathways such as Wnt/β-catenin, Notch, TGF-β, Hedgehog, and NF-κB. Emerging studies have identified lncRNAs that modulate breast cancer's growth, progression, and metastasis by interacting with these pathways. To advance the development of innovative diagnostic tools and targeted treatment options, it is crucial to comprehend the intricate relationship between lncRNAs and vital signaling pathways in breast cancer. By fully harnessing the therapeutic potential of lncRNAs, there is a possibility of developing more effective and personalized therapy choices for breast cancer patients. Further investigation is necessary to comprehensively understand the role of lncRNAs within breast cancer signaling pathways and fully exploit their therapeutic potential.

Combined Effect of Genetic Variants on Long-Term Weight Response after Bariatric Surgery

The pathophysiology of body weight control involves complex interactions between hormonal, environmental, behavioral and genetic factors. The purpose of this study was to analyze the association between single nucleotide polymorphisms (SNPs) of 13 genes encoding gastrointestinal peptides, their receptors or the proteins involved in their expression, with long-term weight response in a cohort of 375 patients undergoing bariatric surgery (BS). To evaluate weight response, we combined several variables to define specific response phenotypes six years after surgery. The study protocol was registered in ISRCTN (ID80961259). The analysis of the selected SNPs was performed via allelic discrimination using Taqman^® probes (Applied Biosystems, Foster City, CA, USA). The genotype association study was performed using the SNPstat program, with comparisons adjusted for sex, age, initial body mass index, type 2 diabetes, hypertension diagnosis and the type of surgery. We identified eight genetic variants associated with the weight response to BS, independently of the presurgery patient profile and the type of surgical technique, from which we calculated the unweighted risk score (RS) for each phenotype. The highest scoring category in each RS was significantly associated with lower weight loss (p = 0.0001) and greater weight regain (p = 0.0012) at the end of the follow-up.

Parental Obesity Predisposition and Age of Onset Associate with Poor Response to Bariatric and Metabolic Surgery

INTRODUCTION

Parental predisposition and age of onset may be independently associated with 1-year total weight loss (TWL) failure (< 20%) after metabolic-bariatric surgery (MBS).

METHODS

This cohort study includes all cases of the German StuDoQ|MBE register (2015-2019) with data on parental predisposition, obesity onset, and at least 1-year follow up after primary MBS procedures (n = 14,404). We provide descriptive statistics of the cohort in terms of the main outcome and 1-year TWL failure, and provide characteristics of surgery type subgroups. Finally, we provide a multivariate logistic regression model of 1-year TWL failure.

RESULTS

58.8% and 45.7% of patients reported maternal and paternal predisposition for obesity, respectively. Average onset of obesity was 15.5 years and duration of disease 28.3 years prior to MBS. SG is the most frequently performed procedure (47.2%) followed by RYGB (39.7%) and OAGB (13.1%). Mean 1-year TWL is 32.7 ± 9.3%, and 7.8% (n = 1,119) of patients show TWL failure (< 20%). Multivariate analysis shows independent association of early onset of obesity (< 18 years), male sex, age at operation, pre-operative BMI, pre-operative weight loss, sleeve gastrectomy (SG), and type 2 diabetes (T2D) with 1-year TWL failure (p < 0.001).

CONCLUSION

The proportions of MBS patients that report on paternal and maternal predisposition for obesity are 45.7% and 58.8% respectively, and average age at onset is 15.5 years. 7.8% of patients do not meet current target criteria of successful response to surgery at 1 year. Early onset, male sex, age at operation, pre-operative BMI, pre-operative weight loss, SG, and T2D are independently associated with weight loss failure.

Changes in Eating Behaviors and Their Associations with Weight Loss in Japanese Patients Who Underwent Laparoscopic Sleeve Gastrectomy

BACKGROUND

Metabolic and bariatric surgery (MBS) has been established to provide long-term weight loss in severe obesity. In this study, we investigated the factors that affect post-operative weight loss, with a particular focus on changes in eating behaviors.

METHODS

Time-course changes in body weight and eating behaviors were examined in 49 Japanese patients who underwent laparoscopic sleeve gastrectomy from the first visit to 12 months after surgery. Each eating behavior was evaluated via the questionnaire of the Japan Society for the Study of Obesity.

RESULTS

Pre-operative weight reduction mediated by dietary and lifestyle interventions showed significant positive correlations with weight loss outcomes at 12 months after surgery. We observed significant decreases in scores for most of the eating behaviors 12 months after surgery. However, "emotional eating behavior" scores declined temporarily in the early post-operative period of one month but thereafter returned to the pre-operative level at 12 months. Furthermore, increases in the scores for "emotional eating behavior" and "sense of hunger" from 1 to 12 months post-operatively were significantly associated with poor weight loss.

CONCLUSIONS

Our results demonstrate the beneficial effects of MBS on obesity-related eating behaviors, as well as highlighting "emotional eating behavior" as requiring particular attention.

Metabolic Profile and Metabolite Analyses in Extreme Weight Responders to Gastric Bypass Surgery

Background: Roux-en-Y gastric bypass (RYGB) surgery belongs to the most frequently performed surgical therapeutic strategies against adiposity and its comorbidities. However, outcome is limited in a substantial cohort of patients with inadequate primary weight loss or considerable weight regain. In this study, gut microbiota composition and systemically released metabolites were analyzed in a cohort of extreme weight responders after RYGB. Methods: Patients (n = 23) were categorized based on excess weight loss (EWL) at a minimum of two years after RYGB in a good responder (EWL 93 ± 4.3%) or a bad responder group (EWL 19.5 ± 13.3%) for evaluation of differences in metabolic outcome, eating behavior and gut microbiota taxonomy and metabolic activity. Results: Mean BMI was 47.2 ± 6.4 kg/m² in the bad vs. 26.6 ± 1.2 kg/m² in the good responder group (p = 0.0001). We found no difference in hunger and satiety sensation, in fasting or postprandial gut hormone release, or in gut microbiota composition between both groups. Differences in weight loss did not reflect in metabolic outcome after RYGB. While fecal and circulating metabolite analyses showed higher levels of propionate (p = 0.0001) in good and valerate (p = 0.04) in bad responders, respectively, conjugated primary and secondary bile acids were higher in good responders in the fasted (p = 0.03) and postprandial state (GCA, p = 0.02; GCDCA, p = 0.02; TCA, p = 0.01; TCDCA, p = 0.02; GDCA, p = 0.05; GUDCA, p = 0.04; TLCA, p = 0.04). Conclusions: Heterogenous weight loss response to RYGB surgery separates from patients’ metabolic outcome, and is linked to unique serum metabolite signatures post intervention. These findings suggest that the level of adiposity reduction alone is insufficient to assess the metabolic success of RYGB surgery, and that longitudinal metabolite profiling may eventually help us to identify markers that could predict individual adiposity response to surgery and guide patient selection and counseling.

Lack of Association Between 11 Gene Polymorphisms on Weight Loss One Year After Roux-en-Y Gastric Bypass Surgery in Women

BACKGROUND

Although effective, the impact of bariatric surgery on weight loss is variable, and little is known about the influence of single nucleotide polymorphisms (SNPs). This study investigated the association of eleven SNPs related to obesity with weight loss one year after Roux-Y gastric bypass (RYGB) surgery in female patients.

METHODS

This prospective study included 351 women with obesity. The genotypes for eleven SNPs (GHRL - rs26802; GHSR - rs572169; LEP - rs7799039; LEPR - rs1137101; 5HT2C - rs3813929; UCP2 - rs659366; UCP3 - rs1800849; SH2B1 - rs7498665; TAS1R2 - rs35874116; TAS1R2 - rs9701796; FTO - rs9939609) were determined using real-time polymerase chain reaction (PCR) and TaqMan assays. Anthropometric measurements were performed before and one year after RYGB surgery. To evaluate the factors that influenced the proportion of weight loss 1 year after surgery, beta regression analysis was used. The models were estimated using the SAS software GLIMMIX procedure. The level of significance adopted for the statistical tests was 5%.

RESULTS

The average percentage of total body weight loss in one year was 64.4 ± 5.8% and the median was 65.0%. In assessing the proportion of weight loss in one year after surgery, using univariate analysis (beta regression), no single nucleotide polymorphisms (SNPs) influenced weight loss. And in the multiple analysis, with stepwise process of variable selection, no variable was significant to compose the multiple model.

CONCLUSION

The 11 SNPs investigated did not influence weight loss one year after RYGB surgery in female patients. This result indicates that individual behaviors and other factors might better contribute to the magnitude of loss weight loss in a short period after bariatric surgery. This article is protected by copyright. All rights reserved.

Low-frequency Coding Variants Associated With Body Mass Index Affect the Success of Bariatric Surgery

CONTEXT

A recent study identified 14 low-frequency coding variants associated with body mass index (BMI) in 718 734 individuals predominantly of European ancestry.

OBJECTIVE

We investigated the association of 2 genetic scores (GS) with i) the risk of severe/morbid obesity, ii) BMI variation before weight-loss intervention, iii) BMI change in response to an 18-month lifestyle/behavioral intervention program, and iv) BMI change up to 24 months after bariatric surgery.

METHODS

The 14 low-frequency coding variants were genotyped or sequenced in 342 French adults with severe/morbid obesity and 574 French adult controls from the general population. We built risk and protective GS based on 6 BMI-increasing and 5 BMI-decreasing low-frequency coding variants that were polymorphic in our study.

RESULTS

While the risk GS was not associated with severe/morbid obesity status, BMI-decreasing low-frequency coding variants were significantly less frequent in patients with severe/morbid obesity than in French adults from the general population. Neither the risk nor the protective GS was associated with BMI before intervention in patients with severe/morbid obesity, nor did they affect BMI change in response to a lifestyle/behavioral modification program. The protective GS was associated with a greater BMI decrease following bariatric surgery. The risk and protective GS were associated with a higher and lower risk of BMI regain after bariatric surgery.

CONCLUSION

Our data indicate that in populations of European descent, low-frequency coding variants associated with BMI in the general population also affect the outcomes of bariatric surgery in patients with severe/morbid obesity.

A Clinical-Genetic Score for Predicting Weight Loss after Bariatric Surgery: The OBEGEN Study

Around 30% of the patients that undergo bariatric surgery (BS) do not reach an appropriate weight loss. The OBEGEN study aimed to assess the added value of genetic testing to clinical variables in predicting weight loss after BS. A multicenter, retrospective, longitudinal, and observational study including 416 patients who underwent BS was conducted (Clinical.Trials.gov- NCT02405949). 50 single nucleotide polymorphisms (SNPs) from 39 genes were examined. Receiver Operating Characteristic (ROC) curve analysis were used to calculate sensitivity and specificity. Satisfactory response to BS was defined as at nadir excess weight loss >50%. A good predictive model of response [area under ROC of 0.845 (95% CI 0.805–0.880), p < 0.001; sensitivity 90.1%, specificity 65.5%] was obtained by combining three clinical variables (age, type of surgery, presence diabetes) and nine SNPs located in ADIPOQ, MC4R, IL6, PPARG, INSIG2, CNR1, ELOVL6, PLIN1 and BDNF genes. This predictive model showed a significant higher area under ROC than the clinical score (p = 0.0186). The OBEGEN study shows the key role of combining clinical variables with genetic testing to increase the predictability of the weight loss response after BS. This finding will permit us to implement a personalized medicine which will be associated with a more cost-effective clinical practice.

Genetic markers of abdominal obesity and weight loss after gastric bypass surgery

Background

Weight loss after bariatric surgery varies widely between individuals, partly due to genetic differences. In addition, genetic determinants of abdominal obesity have been shown to attenuate weight loss after dietary intervention with special attention paid to the rs1358980-T risk allele in the VEGFA locus. Here we aimed to test if updated genetic risk scores (GRSs) for adiposity measures and the rs1358980-T risk allele are linked with weight loss following gastric bypass surgery.

Methods

Five hundred seventy six patients with morbid obesity underwent Roux-en-Y gastric bypass. A GRS for BMI and a GRS for waist-hip-ratio adjusted for BMI (proxy for abdominal obesity), respectively, were constructed. All patients were genotyped for the rs1358980-T risk allele. Associations between the genetic determinants and weight loss after bariatric surgery were evaluated.

Results

The GRS for BMI was not associated with weight loss (β = -2.0 kg/100 risk alleles, 95% CI -7.5 to 3.3, p = 0.45). Even though the GRS for abdominal obesity was associated with an attenuated weight loss response adjusted for age, sex and center (β = -14.6 kg/100 risk alleles, 95% CI -25.4 to -3.8, p = 0.008), it was not significantly associated with weight loss after adjustment for baseline BMI (β = -7.9 kg/100 risk alleles, 95% CI -17.5 to 1.6, p = 0.11). Similarly, the rs1358980-T risk allele was not significantly associated with weight loss (β = -0.8 kg/risk allele, 95% CI -2.2 to 0.6, p = 0.25).

Discussion

GRSs for adiposity derived from large meta-analyses and the rs1358980-T risk allele in the VEGFA locus did not predict weight loss after gastric bypass surgery. The association between a GRS for abdominal obesity and the response to bariatric surgery may be dependent on the association between the GRS and baseline BMI.

A Genetic Risk Score for the Estimation of Weight Loss After Bariatric Surgery

BACKGROUND

Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are the most frequent bariatric surgery procedures worldwide. In this prospective study, we examined the association of a genetic risk score (GRS) with loss of excess weight after bariatric surgery.

METHODS

A total of forty-seven morbidly obese Greek patients who underwent SG (81%) or RYGB were recruited, followed up for 2 years and genotyped. Weight loss after surgery was reported as the percentage of excess weight that was lost (%EWL) at 12 and 24 months after surgery. A GRS was constructed based on previously BMI- and WHR-related single nucleotide polymorphisms (SNPs) that were found significantly correlated with weight loss after bariatric surgery in our population. The level of post-surgery %EWL after 12 and 24 months was estimated through two multiple linear regression models that considered the effects of relevant genetic risk variants.

RESULTS

The first proposed model suggested that the predictor variables of GRS, age, and BMI had a significant effect on %EWL12m. GRS was significantly associated with %EWL12m, indicating a 4.618% decrease of %EWL12m per score unit. The second model indicated a positive correlation between %EWL24m and %EWL12m, suggesting that while post-surgery weight loss increased during the first 12 months, an increase was expected in the next 12 months as well. GRS was also significantly associated with %EWL24m, indicating approximately 3% decrease of %EWL24m per score unit.

CONCLUSION

GRS can be used in the future together with other preoperative parameters in order to predict the outcome of bariatric surgery.

SGCG rs679482 Associates With Weight Loss Success in Response to an Intensively Supervised Outpatient Program

Weight loss in response to energy restriction is highly variable, and identification of genetic contributors can provide insights into underlying biology. Leveraging 1000 Genomes imputed genotypes, we carried out genome-wide association study (GWAS) analysis in 551 unrelated obese subjects of European ancestry who participated in an intensively supervised weight loss program with replication of promising signals in an independent sample of 1,331 obese subjects who completed the program at a later date. By single nucleotide polymorphism-based and sib-pair analysis, we show that that weight loss is a heritable trait, with estimated heritability (h ² = 0.49) within the range reported for obesity. We find rs679482, intronic to SGCG (sarcoglycan γ), highly expressed in skeletal muscle, to concordantly associate with weight loss in discovery and replication samples reaching GWAS significance in the combined meta-analysis (β = -0.35, P = 1.7 × 10^-12). Located in a region of open chromatin, rs679482 is predicted to bind DMRT2, and allele-specific transcription factor binding analysis indicates preferential binding of DMRT2 to rs679482-A. Concordantly, rs679482-A impairs native repressor activity and increases basal and DMRT2-mediated enhancer activity. These findings confirm that weight loss is a heritable trait and provide evidence by which a novel variant in SGCG, rs679482, leads to impaired diet response.

Pre-operative Predictors of Weight Loss and Weight Regain Following Roux-en-Y Gastric Bypass Surgery: a Prospective Human Study

BACKGROUND

There are currently few pre-operative predictors of initial and long-term weight loss following bariatric surgery.

OBJECTIVES

We evaluated the role of pre-operative patient characteristics and baseline gut and adipose-derived hormones in predicting maximal total body weight loss (WL_max) and risk of weight regain (WR) after Roux-en-Y gastric bypass (RYGB) surgery.

METHODS

One hundred five adult patients undergoing primary RYGB were prospectively recruited. Baseline demographics were recorded and fasting plasma glucose, glycosylated hemoglobin (A1C), insulin, glucagon, leptin, active ghrelin, glucagon-like peptide 1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) levels were measured on day of surgery.

RESULTS

Our cohort had a mean age of 44.4 ± 13.0 years, and initial BMI (body mass index) of 45.1 ± 6.7 kg/m² with mean post-operative follow-up of 40 months. Eighty patients were female and 26 had type 2 diabetes mellitus (T2D). Average WL_max was 35.3 ± 7.4%. On univariate analysis, higher baseline fasting ghrelin, lower age, lower CRP (C-reactive protein), lower A1C, and negative T2D status were associated with greater WL_max (p < 0.05). Controlling for these variables using stepwise multivariate regression, only higher fasting ghrelin and younger age were associated significantly with greater WL_max (p < 0.05). In subgroup multivariate regression analysis of T2D patients, higher ghrelin and glucagon were significantly associated with greater WL_max. Following stepwise multivariate regression, lower initial BMI and lower glucagon were associated with greater WR (p < 0.05).

CONCLUSIONS

Incorporation of baseline biological and hormonal markers may help in developing more accurate predictive models for weight loss following bariatric surgery that help inform patient counseling and decision-making.

Genetic Determinants of Weight Loss After Bariatric Surgery

BACKGROUND

The weight loss after bariatric surgery shows considerable individual variation. Twin studies of response to dietary interventions and studies of bariatric surgery patients suggest that genetic differences may play a role. This study aimed to examine the effect of three genetic risk scores on the inter-individual variation in excess body mass index loss (EBMIL) after Roux-en-Y gastric bypass. Furthermore, we searched among known adiposity-related single nucleotide polymorphisms (SNPs) for genetic determinants of the inter-individual variation in EBMIL.

METHODS

Patients with morbid obesity underwent Roux-en-Y gastric bypass and were genotyped (n = 577). Two genetic risk scores for weight loss after bariatric surgery and a genetic risk score for body mass index were calculated. Associations between the genetic risk scores and EBMIL were evaluated. Lasso regression was performed on 126 SNPs known to be associated with adiposity.

RESULTS

The average EBMIL was 76.9% (range 21.7-149.2%). EBMIL was 81.1% (SD 20.6) and 73.9% (SD 21.7) in the high and low tertile groups of a genetic risk score for weight loss. Patients with a low genetic risk score for body mass index (in the lowest 5% percentile) had an EBMIL of 68.8% (SD 20.6, p = 0.018). Thirteen adiposity-related SNPs were identified to associate with EBMIL through lasso regression.

DISCUSSION

A genetic risk score was associated with EBMIL after bariatric surgery, but may not yet be applicable to clinical practice. Patients genetically predisposed to low body mass index had lower weight loss after bariatric surgery.

Eroded Gastric Band: Where to Next? An Analysis of the Largest Contemporary Series

PURPOSE

Erosion of a laparoscopic adjustable gastric band (LAGB) is a devastating problem. There is no clear evidence in literature to guide the choice of revisional procedure following an eroded LAGB. The purpose of this study is to analyse the largest series of erosions following LAGB published to-date with an aim to share our experience with this rare complication and how we managed this cohort of patients following explantation of their LAGB.

MATERIALS AND METHODS

This is a retrospective cohort study. Patient data is maintained prospectively in a surgical database. The study period was from January 1996 to January 2019. The outcomes of patients who underwent an erosion of LAGB were studied.

RESULTS

Gastric band erosion was encountered in 4.7% of patients. Sixty patients opted for a revisional procedure which included 37 repeat LAGBs, 6 laparoscopic sleeve gastrectomies (LSG), 7 Roux-en-Y gastric bypasses (RYGB), 1 intragastric balloon, and 9 failed revisional procedures. Re-erosions were noted in 27% of patients who underwent a repeat gastric banding. Median %TWL at a 1-year follow-up was significantly higher in LSG and RYGB groups compared with that in LAGB (P < 0.008 and P < 0.000, respectively). There was no significant difference between the LSG and RYGB groups.

CONCLUSION

The risk of re-erosion is increased in patients who undergo repeat AGB following a previous episode of erosion. Repeat LAGB should not be offered after a previous erosion. LSG and RYGB should be considered as appropriate revisional procedures in a patient who experience weight regain following explantation of an eroded LAGB.

Effects of Bariatric Surgery in Early- and Adult-Onset Obesity in the Prospective Controlled Swedish Obese Subjects Study

OBJECTIVE

Bariatric surgery is an effective treatment for obesity, but it is unknown if outcomes differ between adults with early- versus adult-onset obesity. We investigated how obesity status at 20 years of age affects outcomes after bariatric surgery later in life.

RESEARCH DESIGN AND METHODS

The Swedish Obese Subjects study is a prospective matched study performed at 25 surgical departments and 480 primary health care centers. Participants aged 37-60 years with BMI ≥34 kg/m² (men) or ≥38 kg/m² (women) were recruited between 1987 and 2001; 2,007 participants received bariatric surgery and 2,040 usual care. Self-reported body weight at 20 years of age was used to stratify patients into subgroups with normal BMI (<25 kg/m²), overweight (BMI 25-29.9 kg/m²), or obesity (BMI ≥30 kg/m²). Body weight, energy intake, and type 2 diabetes status were examined over 10 years, and incidence of cardiovascular and microvascular disease was determined over up to 26 years using data from health registers.

RESULTS

There were small but statistically significant differences in reduction of body weight among the subgroups after bariatric surgery (interaction P = 0.032), with the largest reductions among those with obesity aged 20 years. Bariatric surgery increased type 2 diabetes remission (odds ratios 4.51, 4.90, and 5.58 in subgroups with normal BMI, overweight, or obesity at 20 years of age, respectively; interaction P = 0.951), reduced type 2 diabetes incidence (odds ratios 0.15, 0.13, and 0.15, respectively; interaction P = 0.972), and reduced microvascular complications independent of obesity status at 20 years of age (interaction P = 0.650). The association between bariatric surgery and cardiovascular disease was similar in the subgroups (interaction P = 0.674). Surgical complications were similar in the subgroups.

CONCLUSIONS

The treatment benefits of bariatric surgery in adults are similar regardless of obesity status at 20 years of age.

Preoperative considerations for the pediatric patient undergoing metabolic and bariatric surgery

To ensure successful outcomes in pediatric patients with severe obesity who undergo metabolic and bariatric surgery (MBS), a number of pre-operative patient management options should be considered. This manuscript will review the indications and contraindications of MBS and special considerations for youth who might benefit from MBS. The treatment team conducts a thorough pre-operative evaluation, assessing risks and benefits of surgical intervention, and prepares patients and families to be successful with MBS by providing education about the surgical intervention and lifestyle changes that will be necessary. This article reviews the pre-operative considerations for adolescents with severe obesity who are being considered for MBS, based upon recent clinical practice guidelines.

MC4R Variant rs17782313 Associates With Increased Levels of DNAJC27, Ghrelin, and Visfatin and Correlates With Obesity and Hypertension in a Kuwaiti Cohort

Melanocortin 4 receptor (MC4R), a notable component of the melanocortin system, regulates appetite, body weight, and energy homeostasis. Genome-wide association studies have identified several MC4R variants associated with adiposity; of these, rs17782313, which is associated with increased body mass index (BMI) and overeating behavior, is of particular interest. Another gene associated with increased adiposity in global genome-wide association studies is DNAJC27, a heat shock protein known to be elevated in obesity. The detailed mechanisms underlying the role of MC4R variants in the biological pathways underlying metabolic disorders are not well-understood. To address this, we assessed variations of rs17782313 in a cohort of 282 Arab individuals from Kuwait, who are deeply phenotyped for anthropometric and metabolic traits and various biomarkers, including DNAJC27. Association tests showed that the rs17782313_C allele was associated with BMI and DNAJC27 levels. Increased levels of DNAJC27 reduced the MC4R-mediated formation of cAMP in MC4R ACTOne stable cells. In conclusion, this study demonstrated an association between the rs17782313 variant near MC4R and increased BMI and DNAJC27 levels and established a link between increased DNAJC27 levels and lower cAMP levels. We propose that regulation of MC4R activity by DNAJC27 enhances appetite through its effect on cAMP, thereby regulating obesity.

A pharmacogenetic risk score for the evaluation of major depression severity under treatment with antidepressants

The severity of symptoms as well as efficacy of antidepressants in major depressive disorder (MDD) is modified by single nucleotide polymorphisms (SNPs) in different genes, which may contribute in an additive or synergistic fashion. We aimed to investigate depression severity in participants with MDD under treatment with antidepressants in relation to the combinatory effect of selected genetic variants combined using a genetic risk score (GRS). The sample included 150 MDD patients on regular AD therapy from the population‐based Swiss PsyCoLaus cohort. We investigated 44 SNPs previously associated with antidepressant response by ranking them with regard to their association to the Center for Epidemiologic Studies Short Depression Scale (CES‐D) score using random forest. The three top scoring SNPs (rs12248560, rs878567, rs17710780) were subsequently combined into an unweighted GRS, which was included in linear and logistic regression models using the CES‐D score, occurrence of a major depressive episode (MDE) during follow‐up and regular antidepressant treatment during the 6 months preceding follow‐up assessment as outcomes. The GRS was associated with MDE occurrence (p = .02) and ln CES‐D score (p = .001). The HTR1A rs878567 variant was associated with ln CES‐D after adjustment for demographic and clinical variables [p = .02, lower scores for minor allele (G) carriers]. Additionally, rs12248560 (CYP2C19) CC homozygotes showed a six‐fold higher likelihood of regular AD therapy at follow‐up compared to minor allele homozygotes [TT; ultrarapid metabolizers (p = .03)]. Our study suggests that the cumulative consideration of pharmacogenetic risk variants more reliably reflects the impact of the genetic background on depression severity than individual SNPs.

Diagnosis of obesity and use of obesity biomarkers in science and clinical medicine

The global epidemic of obesity is a major public health problem today. Obesity increases the risk of many chronic diseases, such as type 2 diabetes, coronary heart disease, and certain types of cancer, and is associated with lower life expectancy. The body mass index (BMI), which is currently used to classify obesity, is only an imperfect measure of abnormal or excessive body fat accumulation. Studies have shown that waist circumference as a measure of fat distribution may improve disease prediction. More elaborate techniques such as magnetic resonance imaging are increasingly available to assess body fat distribution, but these measures are not readily available in routine clinical practice, and health-relevant cut-offs not yet been established. The measurement of biomarkers that reflect the underlying biological mechanisms for the increased disease risk may be an alternative approach to characterize the relevant obesity phenotype. The insulin/insulin-like growth factor (IGF) axis and chronic low-grade inflammation have been identified as major pathways. In addition, specific adipokines such as leptin, adiponectin and resistin have been related to obesity-associated health outcomes. This biomarker research, which is currently further developed with the application of high throughput methods, gives important insights in obesity-related disease etiology and pathophysiological pathways and may be used to better characterize obese persons at high risk of disease development and target disease-causing biomarkers in personalized prevention strategies.

Melanocortin-4 Receptor Signalling: Importance for Weight Regulation and Obesity Treatment

The melanocortin-4 receptor (MC4R) - embedded in the leptin-melanocortin pathway - is activated by proopiomelanocortin (POMC)-derived neuropeptides such as α- and β-melanocyte-stimulating hormone (MSH) and plays an important role in hypothalamic body-weight regulation. Accordingly, MC4R is a potential drug target to combat obesity. Previous attempts to develop MC4R agonists failed due to ineffectiveness or severe adverse events. Recently, a new generation of MC4R ligands was developed. Specifically, setmelanotide was found to be effective by inducing biased signalling of the MC4R and thereby reducing feelings of hunger and leading to substantial weight loss in patients with POMC or leptin receptor deficiency. This new potential pharmacological treatment option could be beneficial for further groups of obese patients with defects in the leptin-melanocortin signalling pathway.

Polygenic risk score for predicting weight loss after bariatric surgery

BACKGROUND

The extent of weight loss among patients undergoing bariatric surgery is highly variable. Herein, we tested the contribution of genetic background to such interindividual variability after biliopancreatic diversion with duodenal switch.

METHODS

Percentage of excess body weight loss (%EBWL) was monitored in 865 patients over a period of 48 months after bariatric surgery, and two polygenic risk scores were constructed with 186 and 11 (PRS186 and PRS11) single nucleotide polymorphisms previously associated with body mass index (BMI).

RESULTS

The accuracy of the %EBWL logistic prediction model - including initial BMI, age, sex, and surgery modality, and assessed as the area under the receiver operating characteristics (ROC) curve adjusted for optimism (AUCadj = 0.867) - significantly increased after the inclusion of PRS186 (ΔAUCadj = 0.021; 95% CI of the difference [95% CIdiff] = 0.005-0.038) but not PRS11 (ΔAUCadj= 0.008; 95% CIdiff= -0.003-0.019). The overall fit of the longitudinal linear mixed model for %EBWL showed a significant increase after addition of PRS186 (-2 log-likelihood = 12.3; P = 0.002) and PRS11 (-2 log-likelihood = 9.9; P = 0.007). A significant interaction with postsurgery time was found for PRS186 (β = -0.003; P = 0.008) and PRS11 (β = -0.008; P = 0.03). The inclusion of PRS186 and PRS11 in the model improved the cost-effectiveness of bariatric surgery by reducing the percentage of false negatives from 20.4% to 10.9% and 10.2%, respectively.

CONCLUSION

These results revealed that genetic background has a significant impact on weight loss after biliopancreatic diversion with duodenal switch. Likewise, the improvement in weight loss prediction after addition of polygenic risk scores is cost-effective, suggesting that genetic testing could potentially be used in the presurgical assessment of patients with severe obesity.

FUNDING

Heart and Stroke Foundation of Canada (G-17-0016627) and Canada Research Chair in Genomics Applied to Nutrition and Metabolic Health (no. 950-231-580).

Localization of adaptive variants in human genomes using averaged one-dependence estimation

Statistical methods for identifying adaptive mutations from population genetic data face several obstacles: assessing the significance of genomic outliers, integrating correlated measures of selection into one analytic framework, and distinguishing adaptive variants from hitchhiking neutral variants. Here, we introduce SWIF(r), a probabilistic method that detects selective sweeps by learning the distributions of multiple selection statistics under different evolutionary scenarios and calculating the posterior probability of a sweep at each genomic site. SWIF(r) is trained using simulations from a user-specified demographic model and explicitly models the joint distributions of selection statistics, thereby increasing its power to both identify regions undergoing sweeps and localize adaptive mutations. Using array and exome data from 45 ‡Khomani San hunter-gatherers of southern Africa, we identify an enrichment of adaptive signals in genes associated with metabolism and obesity. SWIF(r) provides a transparent probabilistic framework for localizing beneficial mutations that is extensible to a variety of evolutionary scenarios.

Lyplal1 is dispensable for normal fat deposition in mice

Genome-wide association studies (GWAS) have detected association between variants in or near the Lysophospholipase-like 1 (LYPLAL1) locus and metabolic traits, including central obesity, fatty liver and waist-to-hip ratio. LYPLAL1 is also known to be upregulated in the adipose tissue of obese patients. However, the physiological role of LYPLAL1 is not understood. To investigate the function of Lyplal1 in vivo we investigated the phenotype of the Lyplal1^{tm1a(KOMP)Wtsi} homozygous mouse. Body composition was unaltered in Lyplal1 knockout mice as assessed by dual-energy X-ray absorptiometry (DEXA) scanning, both on normal chow and on a high-fat diet. Adipose tissue distribution between visceral and subcutaneous fat depots was unaltered, with no change in adipocyte cell size. The response to both insulin and glucose dosing was normal in Lyplal1^{tm1a(KOMP)Wtsi} homozygous mice, with normal fasting blood glucose concentrations. RNAseq analysis of liver, muscle and adipose tissue confirmed that Lyplal1 expression was ablated with minimal additional changes in gene expression. These results suggest that Lyplal1 is dispensable for normal mouse metabolic physiology and that despite having been maintained through evolution Lyplal1 is not an essential gene, suggesting possible functional redundancy. Further studies will be required to clarify its physiological role.

From genetics and epigenetics to the future of precision treatment for obesity

Obesity has become a major global health problem, epitomized by excess accumulation of body fat resulting from an imbalance between energy intake and expenditure. The treatments for obesity range from modified nutrition and additional physical activity, to drugs or surgery. But the curative effect of each method seems to vary between individuals. With progress in the genetics and epigenetics of obesity, personalization of the clinical management of obesity may be at our doorstep. This review presents an overview of our current understanding of the genetics and epigenetics of obesity and how these findings influence responses to treatments. As bariatric surgery is the most effective long-term treatment for morbid obesity, we pay special attention to the association between genetic factors and clinical outcomes of bariatric surgery. Finally, we discuss the prospects for precision obesity treatment.

A genetic risk score is significantly associated with statin therapy response in the elderly population

The ability of statins to strongly reduce low-density lipoprotein cholesterol (LDL-C) varies interindividually and is partially influenced by genetic variants. Based on a comprehensive analysis of 23 single nucleotide polymorphisms (SNPs) known to be associated with pharmacokinetics and dynamics of statins, we developed a genetic risk score to study its impact on the therapy outcome in elderly individuals under at least 5 years statin therapy. The study was performed in a population-based cohort of 1016 elderly individuals, which comprised 168 statin users investigated at age 75 and 80. Using random forest models, the major variants influencing LDL-C levels were summarized in a weighted GRS (wGRS). The wGRS was tested with lipid and glucose outcomes and validated in an independent population-based cohort including 221 statin users. Four SNPs within the APOE cluster (rs7412, rs4420638), ABCC2 (rs2002042) and CELSR/SORT1/PSRC1 (rs646776), displayed a major impact on statin efficacy. The wGRS was significantly associated with lower LDL-C at age 75 and 80. This association was replicated displaying similar results. GRS analysis is a powerful tool to evaluate the additive effects of genetic variants on statin response and to estimate the magnitude of LDL-C reduction to a considerable extent in the older population.