The relationship between weight loss and cognitive function in bariatric surgery

BACKGROUND

Previously, we reported short-term improvements in auditory attention, oromotor processing speed, and executive function during the active weight loss phase following bariatric surgery that persisted out to 3 months. In this study, our aims were to investigate the relationship between weight loss and cognitive performance in these patients 1 year following vertical sleeve gastrectomy (VSG) and Roux-en Y gastric bypass (RYGB) surgery and to determine whether preoperative cognitive performance predicted weight loss.

METHODS

Adult women ages 18-55 approved for bariatric surgery completed a cognitive battery prior to and at 2, 12, 24, and 52 weeks following VSG (N = 17) or RYGB (N = 18). Scores from each task were assigned to one of the following cognitive domains: auditory attention, processing speed, memory, and executive functioning. Weight loss and cognitive scores for each domain were calculated and compared between cohorts.

RESULTS

RYGB surgery resulted in greater weight loss at 1-year follow-up relative to VSG. Both VSG and RYGB procedures resulted in improved performance on different measures of auditory attention and both surgery groups improved across all processing speed tasks. Within the executive function domain, both groups showed improvements, but only the RYGB procedure resulted in improved performance in the Trail Making Test. Baseline auditory attention and memory performance predicted weight loss at 1 year following RYGB but not VSG surgery. Controlling for baseline cognitive performance, percent total weight loss predicted auditory attention at 1 year following RYGB but not VSG surgery.

CONCLUSIONS

Bariatric surgery type may result in selective improvements in cognition during the first year following surgery. Presurgical cognitive performance as well as surgery type appears to influence weight loss outcomes.

Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy effects on obesity comorbidities: A systematic review and meta-analysis

Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) are the most commonly used bariatric procedures. There is an increasing awareness about a comorbidity-based indication for bariatric surgery regardless of weight (metabolic surgery). The best operation to mitigate obesity-associated comorbidities is a matter of controversy. This review is aimed at comparing LRYGB and LSG for the treatment of diabetes, hypertension, dyslipidemias, obstructive sleep apnea (OSA), and gastroesophageal reflux (GERD). We searched PubMed, MEDLINE, SCOPUS, Web of Science, and Cochrane library for articles comparing these two commonly used bariatric approaches. We identified 2,457 studies, 1,468 of which stood after the removal of duplications; from them, 81 full texts were screened and only 16 studies were included in the final meta-analysis. LRYGB was equal weight to LSG for diabetes (P-value = 0.10, odd ratio, 1.24, 95% CI, 0.96-1.61, I ² for heterogeneity = 30%, P-value for heterogeneity, 0.14), and OSA (P-value = 0.38, odd ratio, 0.79, 95% CI, 0.47-1.33, I ² for heterogeneity = 0.0%, P-value for heterogeneity, 0.98). However, LRYGB was superior to LSG regarding hypertension (P-value = 0.009, odd ratio, 1.55, 95% CI, 1.20-2.0, I ² for heterogeneity = 0.0%, P-value for heterogeneity, 0.59), dyslipidemia (odd ratio, 2.18, 95% CI, 1.15-4.16, P-value for overall effect, 0.02), and GERD (P-value = 0.003, odd ratio, 3.16, 95% CI, 1.48-6.76). LRYGB was superior to LSG for gastroesophageal reflux, hypertension, and dyslipidemia remission. While the two procedures were equal regarding diabetes and obstructive sleep, further reviews comparing LSG, and one anastomosis gastric bypass are recommended.

Metabolic profiles, energy expenditures, and body compositions of the weight regain versus sustained weight loss patients who underwent Roux-en-Y gastric bypass

BACKGROUND

Weight regain (WR) has been an emerging problem after Roux-en Y gastric bypass (RYGB) and little is known about the mechanisms of WR after RYGB.

OBJECTIVE

To evaluate the mechanisms of WR after RYGB through the postprandial gut hormones response, particularly glucagon-like peptide-1 (GLP-1), which regulates appetite control, energy expenditure, body composition, physical activities, dietary intake, and psychological factors.

SETTING

Duke University Medical Center, Durham, North Carolina.

METHODS

A cross sectional study of 34 patients who underwent RYGB at least 2 years and achieved ≥50% of excess weight loss at 1year was conducted. The subjects were categorized into WR group or sustained weight loss group, based upon whether their WR was ≥15% of postoperative lowest weight.

RESULTS

The WR group had less augmented postprandial GLP-1 response but exaggerated hyperinsulinemia. Postprandial peptide YY, ghrelin, and glucose were not different between group. Patients who regained weight required less weight-adjusted energy expenditure and had more percentage body fat and less percentage lean mass. The caloric intake and diet composition were comparable between groups; however, the WR group had higher depression scores, binge eating scales, and hunger rating and spent significantly less time on vigorous exercise.

CONCLUSIONS

The mechanisms of WR in patients who were initially successful after RYGB are complex and involved not only the role of postprandial gut hormone response but are also related to energy expenditure adaptation and body composition changes. Moreover, food preference and physical activity may play roles in weight control after bariatric surgery. Further prospective controlled trial is needed to explore the mechanisms of WR.

Review of the Endoscopic, Surgical and Radiological Techniques of Treating Choledocholithiasis in Bariatric Roux-en-Y Gastric Bypass Patients and Proposed Management Algorithm

Choledocholithiasis in post-surgical bariatric Roux-en-Y gastric bypass patients presents a significant challenge secondary to altered anatomy. We aim to review the existing management options including either endoscopic, surgical, percutaneous or hybrid means. Current literature suggests reasonably successful cannulation rates for single- or double-balloon ERCP ranging from 50 to 70% and 63-83%, respectively. The hybrid technique of laparoscopic transgastric ERCP has gained popularity with success rates ranging from 90 to 100%. Conventional laparoscopic techniques like transcystic duct and transcholedochal bile duct exploration are still useful options (i.e. high success rates of 81-100% and 83-96%, respectively). The role of percutaneous transhepatic choledochography remains limited although it can help with rapid bile duct decompression. If feasible, treatment pathways should progress from least to more invasive options as required.

Inquiry into the short- and long-term effects of Roux-en-Y gastric bypass on the glomerular filtration rate

Bariatric surgery is known to attenuate glomerular hyperfiltration over the long term and thereby protect the kidney from mechanical damage. Whether this effect is directly related to weight loss or is independent of weight as are some of its other beneficial metabolic effects is not known. We explored this question in a preliminary study that directly measured glomerular filtration rate (GFR) before, immediately after, and again many months after Roux-en-Y gastric bypass after large weight loss had occurred. We simultaneously measured stimulated circulating glucagon-like peptide-1, which is upregulated after Roux-en-Y gastric bypass and is a putative mediator of GFR after bariatric surgery. We found no weight-independent effect of Roux-en-Y gastric bypass on GFR nor an association between circulating GLP-1 levels and GFR. These findings, if confirmed in larger studies, will help steer future enquiries in this area.

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.

Reappraisal learning curve of laparoscopic Roux-en Y gastric bypass: retrospective results of one hundred and eight cases from a low-volume unit

Background

This study aimed to reevaluate the learning curve of laparoscopic Roux-en Y gastric bypass (LRYGB) in the modern era while considering a single surgeon’s experience.

Methods

From the beginning of our LRYGB practice, all patients who met the regional criteria and underwent primary LRYGB were retrospectively enrolled. Patients with a body mass index (BMI) > 50 kg/m² were excluded. Those who underwent surgery in 2016–17, 2018 and 2019 by a single surgeon with 10 + years of laparoscopic experience were assigned to groups A, B and C, respectively. The patient demographics and 30-day outcome data, including the operation time, length of stay (LOS), emergency room visits, readmission, and reoperation, were compared among the groups.

Results

One hundred and eight patients met the inclusion criteria; 36, 38, and 34 patients were assigned to groups A, B and C, respectively. There were no differences in age, sex distribution or common comorbidities among the groups; however, B had a lower BMI (35.1 kg/m² vs. 37.0 kg/m²) and a higher rate of hypertension (44.7% vs. 22.2%) than group A. The operation time was markedly reduced (96.1 min and 114.9 min, p < 0.001), and the LOS was shortened (2.2 days and 2.9 days, p < 0.001) in group B compared to group A and remained stationary in group C, with no further reduction in 30-day complications.

Conclusion

The learning process of LRYGB can be shortened to approximately 30 cases if conducted selectively by experienced laparoscopic surgeons. Further follow-up is required to verify the long-term safety and applicability in other patient subgroups.

Preoperative predictors of early relapse/no-remission of type-2 diabetes after metabolic surgery in Chinese patients

Remission of type 2 diabetes mellitus (T2DM) after metabolic surgery in some patients is not sustained. There is limited data regarding the preoperative factors predicting early relapse of T2DM in Chinese patients. The objective of this study is to look for preoperative predictors of early T2DM relapse/no remission in patients with obesity and diabetes who underwent Roux-en-Y gastric bypass (RYGB) or loop duodeno-jejunal bypass with sleeve gastrectomy (LDJB-SG). This is a retrospective study of 113 patients who underwent RYGB or LDJB-SG for T2DM. All T2DM patients with BMI 27.5 to 37.5 kg/m² , having uncontrolled diabetes and T2DM patients with BMI > 37.5 were included in the study. A multivariate analysis with a logistic regression model was used for analysed factors. Nineteen patients (16.8%) had early relapse and 12 (10.6%) did not have remission. Mean age of patients was significantly more who relapsed/no-remission (44.9 vs 40.3 years). On univariate analysis, base line weight (86 vs 96.7 kg) was significantly lower in patients who relapsed/no-remission. Patients with sustained remission had statistically significant low glycosylated haemoglobin (P < .030), plasma glucose (120 minutes) (P < .002) on OGTT, area under curve glucose (P < .011) values and more C-peptide (P < .006) on univariate analysis. Only duration of diabetes (OR 2.78, 95% CI 1.56-4.97, P < .001) was found to be independent preoperative factor associated with early relapse/no-remission. Two years of diabetes duration was the cut-off point to predict relapse/no-remission (sensitivity 78.9, specificity 63.4, receiver operating characteristic curve 0.71). Duration of diabetes is the most probable, independent preoperative predictor of early T2DM relapse/no-remission in patient with obesity and diabetes undergoing metabolic surgery.

The learning curve of one anastomosis gastric bypass and its impact as a preceding procedure to Roux-en Y gastric bypass: initial experience of one hundred and five consecutive cases

Background

The aim of this study was to assess the learning curve of one anastomosis gastric bypass (OAGB-MGB) at the start of a low volume bariatric unit and analyze its impact as a preceding procedure to Roux-en Y gastric bypass (RYGB).

Methods

From January 2014 to December 2017, all patients who underwent bariatric surgeries in our teaching hospital that were performed by the same surgeon were enrolled. The first 47 patients who underwent OAGB-MGB were assigned to group A. RYGB has been offered as a treatment option since July 2016; thereafter, 26 patients who underwent OAGB-MGB and 32 patients who underwent RYGB at the same time interval were assigned to group B and group C, respectively. Baseline characteristics, perioperative outcomes and percentage of total weight loss (%TWL) up to 12 months postoperatively were collected and analyzed between groups.

Results

Compared to the patients in group C, those in groups A and B were older (39.4 yrs. and 42.2 yrs., respectively, vs. 34.2 yrs.; p = 0.021) and predominantly male (48.9 and 73.1%, respectively vs. 40.6%; p = 0.04), and they had a higher body mass index (41.8 kg/m² and 43.3 kg/m², respectively vs. 37.7 kg/m²; p = 0.002) and a higher incidence of hypertension (44.7 and 61.5%, respectively vs. 21.9%; p = 0.008). In addition, the operation time was significantly reduced (118.2 min and 115.8 min, respectively vs. 153.1 min; p <  0.001), and the length of stay was shortened (3.0 days and 2.9 days, respectively vs. 3.4 days; p = 0.002) in groups B and C compared to group A. No mortality, conversion or leakage was reported throughout the study period. The 30-day complication rate was decreased in group C compared to groups A and B (0% vs. 6.4 and 7.7%, respectively; p = 0.307). The %TWL at the 12-month follow-up was 36.3, 30.9 and 28.3% for groups A, B and C, respectively (p <  0.001).

Conclusion

Our study verified the early emergence of a learning curve effect for OAGB-MGB, and the proficiency acquired can be transferred to subsequent practice for RYGB in terms of acceptable operation time and length of stay without an increase in complications.

Short-term improvements in cognitive function following vertical sleeve gastrectomy and Roux-en Y gastric bypass: a direct comparison study

BACKGROUND

Cognitive deficits are observed in individuals with obesity. While bariatric surgery can reverse these deficits, it remains unclear whether surgery type differentially influences cognitive outcome. We compared the extent to which vertical sleeve gastrectomy (VSG) and Roux-en Y gastric bypass (RYGB) ameliorated cognitive impairments associated with obesity.

METHODS

Female participants approved for VSG (N = 18) or RYGB (N = 18) were administered cognitive measures spanning the domains of attention [Hopkins Verbal Learning Test (HVLT) Trial 1 and Letter Number Sequencing], processing speed [Stroop Color Trial, Symbol Digit Modalities Test, and Trail Making Part A], memory [HVLT Retained and HVLT Discrimination Index], and executive functioning (Stroop Color Word Trials and Trail Making Part B-A) prior to surgery and at 2 weeks and 3 months following surgery. Scores for each cognitive domain were calculated and compared between surgical cohorts using repeated measures analyses of variance.

RESULTS

Significant weight loss was observed 2 weeks and 3 months following RYGB and VSG and was accompanied by improvements in processing speed and executive functioning. Patients who received RYGB also experienced improved attention as early as 2 weeks, which persisted at 3 months. This was not observed in individuals who underwent VSG. No changes in memory were observed from baseline measures in either group.

CONCLUSIONS

This is the first report of cognitive improvements following VSG and the first direct comparison of cognitive improvements following RYGB and VSG. Short-term improvements in specific domains of cognitive function are observed at the beginning of the active weight loss phase following bariatric surgery that persisted to 3 months. The anatomical distinction between the two surgeries and resulting differential metabolic profiles may be responsible for the improvements in attention observed following RYGB but not following VSG.

Robot-assisted sleeve gastrectomy and Roux-en-y gastric bypass: results from the metabolic and bariatric surgery accreditation and quality improvement program data registry

BACKGROUND

A stronger evidence base is needed to more fully understand the precise role that robot-assisted (RA) approaches may play in bariatrics.

OBJECTIVE

To investigate the utilization and safety of RA-sleeve gastrectomy (RA-SG) and RA-Roux-en-Y gastric bypass (RA-RYGB) using data from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) registry.

SETTING

National Database.

METHODS

We queried the MBSAQIP 2015 through 2016 registry for patients who underwent primary conventional laparoscopic or RA-SG and RA-RYGB. We compared pre- and perioperative characteristics and 30-day outcomes using logistic regression where number of events met statistical guidelines.

RESULTS

We included 126,987 cases: conventional laparoscopic SG (n = 83,940), RA-SG (n = 6,780), conventional laparoscopic RYGB (n = 33,525), and RA-RYGB (n = 2,742). The RA significantly lengthened operation time by 24 and 23 minutes for SG and RYGB, respectively. Mortality and serious adverse events were similar for the 2 techniques. RA-SG was associated with higher rates of 30-day intervention (1.3% versus .8%, OR: 1.38, P < .05) and hospital stay >2 days (12.1% versus 9.3%, OR: 1.30, P < .001). RA-RYGB was associated with higher 30-day rates of reoperation (2.6% versus 2.0%, OR: 1.37, P < .05) and readmission (7.0% versus 5.8%, OR:1.21, P < .05) and lower rates of transfusion (0.62% versus 1.12%, OR: .54, P < .05) and hospital stay >2 days (15.7% versus 17%, OR: .89, P < .05).

CONCLUSION

RA is as safe as the conventional laparoscopic approach in terms of mortality and serious adverse events.

Metabolomic fingerprint of severe obesity is dynamically affected by bariatric surgery in a procedure-dependent manner

BACKGROUND

Obesity is associated with multiple diseases. Bariatric surgery is the most effective therapy for severe obesity that can reduce body weight and obesity-associated morbidity. The metabolic alterations associated with obesity and respective changes after bariatric surgery are incompletely understood.

OBJECTIVE

We comprehensively assessed metabolic alterations associated with severe obesity and distinct bariatric procedures.

DESIGN

In our longitudinal observational study, we applied a (1)H-nuclear magnetic resonance-based global, untargeted metabolomics strategy on human serum samples that were collected before and repeatedly ≤1 y after distinct bariatric procedures [i.e., a sleeve gastrectomy, proximal Roux-en Y gastric bypass (RYGB), and distal RYGB]. For comparison, we also analyzed serum samples from normal-weight and less-obese subjects who were matched for 1-y postoperative body mass index (BMI) values of the surgical groups.

RESULTS

We identified a metabolomic fingerprint in obese subjects that was clearly discriminated from that of normal-weight subjects. Furthermore, we showed that bariatric surgery (sleeve gastrectomy and proximal and distal RYGB) dynamically affected this fingerprint in a procedure-dependent manner, thereby establishing new fingerprints that could be discriminated from those of BMI-matched and normal-weight control subjects. Metabolites that largely contributed to the metabolomic fingerprints of severe obesity were aromatic and branched-chain amino acids (elevated), metabolites related to energy metabolism (pyruvate and citrate; elevated), and metabolites suggested to be derived from gut microbiota (formate, methanol, and isopropanol; all elevated).

CONCLUSION

Our data indicate that bariatric surgery, irrespective of the specific kind of procedure used, reverses most of the metabolic alterations associated with obesity and suggest profound changes in gut microbiome-host interactions after the surgery. This trial was registered at clinicaltrials.gov as NCT02480322.

Effects of Roux-en-Y gastric bypass and ileal transposition surgeries on glucose and lipid metabolism in skeletal muscle and liver

BACKGROUND

Roux-en Y gastric bypass (RYGB) and ileal transposition (IT) surgeries produce weight loss and improve diabetic control; however, the mechanisms of glycemic improvements are largely unknown. Because skeletal muscle and liver play a key role in glucose homeostasis, we compared the effects of RYGB and IT surgeries on key molecules of glucose and lipid metabolism in muscle and liver.

METHODS

Sprague-Dawley rats were subjected to RYGB, IT, or sham surgeries; sham-animals were ad-lib fed or pair-fed to RYGB rats (n = 7-9/group). At 8 weeks postoperatively, blood samples were collected for glucagon-like peptide-1 (GLP-1) and insulin analyses by ELISA. Leg muscle and liver tissues were analyzed for mRNA (RT-qPCR) and/or protein abundance (immuno blotting) of important molecules of glucose and lipid metabolism [glucose transporter-4 (GLUT-4), hexokinase, phosphofructokinase (PFK), adenosine monophosphate activated protein kinase-α (AMPKα), cytochrome C oxidase-IV (COX-IV), citrate synthase, carnitine palmitoyl transferase-1 (CPT-1), medium-chain acyl-CoA dehydrogenase (MCAD), peroxisome proliferator-activated receptor gamma co-activator 1 α (PGC-1 α), PGC-1-related coactivator (PRC), uncoupling protein-3 (UCP-3)].

RESULTS

Plasma GLP-1 concentrations were increased comparably with RYGB and IT. RYGB and IT increased muscle GLUT-4 protein content, muscle hexokinase mRNA, and liver PFK mRNA. IT increased muscle AMPKα and COX-IV protein content and liver citrate synthase activity. IT increased muscle CPT-1, MCAD and PRC mRNA, whereas RYGB increased UCP-3 mRNA in muscle and liver, and PGC-1 α mRNA in liver.

CONCLUSION

The data suggest that RYGB and IT surgeries lead to enhanced GLP-1 secretion and produce similar stimulatory effects on important molecules of glucose metabolism but differential effects on key molecules of lipid oxidation in muscle and liver.

Bariatric surgery-mediated weight loss and its metabolic consequences for type-2 diabetes

The worldwide epidemic of obesity and its medical complications are being dealt with a combination of life style changes (e.g., healthier diet and exercise), medications and a variety of surgical interventions. The Roux-en Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB) are two of the most common weight loss surgeries for morbid obesity-associated metabolic syndrome and insulin resistance. A vast majority of patients that undergo RYGB and LAGB are known to experience marked weight loss and attenuation of diabetes. A number of recent studies have indicated that the rates of remission in glycemic control and insulin sensitivity are significantly greater in patients that have undergone RYGB. A plausible hypothesis to explain this observation is that the gastric bypass surgery as opposed to the gastric banding procedure impinges on glucose homeostasis by a weight loss-independent mechanism. In a recent paper, Bradley et al have experimentally explored this hypothesis. The authors compared several clinical and laboratory parameters of insulin sensitivity and β-cell function in cohorts of RYGB and LAGB patients before and after they lost approximately 20% of their body mass. After weight loss, both groups of patients underwent similar changes in their intra-abdominal and total adipose tissue volume, hepatic triglyceride and circulating leptin levels. The RYGB patients who lost 20% body mass, manifested higher postprandial output of glucose, insulin and glucagon-like peptide-1; these laboratory parameters remained unchanged in LABG patients. Irrespective of the observed differences in transient responses of RYGB and LAGB patients to mixed meal, the overall glycemic control as judged by glucose tolerance, multi-organ insulin sensitivity and β-cell function were nearly identical in the two groups. Both RYGB and LAGB patient cohorts also experienced similar changes in the expression of a number of pro- and anti-inflammatory markers. Based on these analyses, Bradley et al concluded that similar restoration of insulin sensitivity and b-cell function in non-diabetic obese patients that have undergone RYGB and LAGB were directly due to marked weight loss. These data have important implications for the risk/benefit analysis of weight loss therapy by bariatric procedures.