Background: Improved glycemic control after RYGB may be due to changes in food-associated gut hormone signals that occur independent of weight loss. This study investigates whether effects unique to RYGB improve insulin sensitivity and beta cell function independent of simultaneous enteral nutrient passage.

The objective of this study was to quantify hormones that regulate energy and glucose homeostasis to establish possible mechanisms for the greater efficacy of Roux-en-Y gastric bypass (RYGB) compared with laparoscopic adjustable gastric banding (LAGB) in achieving weight loss and improved insulin sensitivity. Longitudinal study of patients undergoing LAGB (n=15) and RYGB (n=28) who were studied before surgery and at 2, 12, 26 and 52 weeks afterwards. Fasting blood samples were drawn at each visit. Postprandial blood samples were also obtained before surgery and at 26 and 52 weeks. Samples were assayed for peptide YY (PYY), ghrelin, glucagon-like peptide-1 (GLP-1), glucose, insulin, leptin, thyrotropic hormone, free T4 and free T3. At 1 year there was greater weight loss in RYGB compared with LAGB patients (30 vs 15%), but final body mass index was similar (34 vs 33 kg m−2). At week 52, area under the curve (AUC) for PYY in RYGB subjects was greater than LAGB (P<0.01). GLP-1 levels at 30 min after meal were threefold greater after RYGB compared with LAGB (P<0.001). Conversely, ghrelin AUC increased after LAGB at week 52 (P<0.05) but tended to decrease after RYGB. Fasting glucose, insulin, and leptin and homeostasis model of assessment (HOMA-IR) decreased in both groups over time but were significantly lower at week 52 after RYGB compared with LAGB. The change in leptin correlated significantly with weight loss in LAGB (r=0.86) and RYGB (r=0.77), however, HOMA-IR correlated significantly with weight loss only in LAGB (r=0.78), and not RYGB (r=0.15). There was a significant decrease in free T3 (P<0.01) after RYGB. Differences in levels of gut hormones may play a role in promoting greater weight loss and insulin sensitivity after RYGB compared with LAGB, however, weight loss may be limited by decreases in free T3 and leptin.

In obese patients with type 2 diabetes (T2DM), gastric bypass leads to a marked improvement in glucose homeostasis soon after surgery but before substantial weight loss has occurred. This observation supports the hypothesis that bypassing the proximal intestine is a key event in improving T2DM. The aim of this study was to study the effect of sleeve gastrectomy and duodenal-jejunal bypass on glucose homeostasis in a non-obese rodent model of T2DM and to evaluate the utility of PET scanning with [11C] dihydrotetrabenazine (DTBZ) for assessing β-cell performance.

OBJECTIVE AND METHODS: Given the profound weight loss after gastric banding and bypass we compared fat compartmentalization by whole body magnetic resonance imaging in women and men after these procedures to two groups of non-surgical controls who were either matched for age, weight and height or were of lower body mass index (BMI). RESULT: In women post-surgery (n=17; BMI 31.7 kg/m(2)) there was lower visceral adipose tissue (VAT) (1.4 vs 2.5 kg; P<0.01) compared with matched controls (n=59; BMI 32.1 kg/m(2)). In contrast, VAT (5.3 vs 5.4 kg) was nearly identical in men post-surgery (n=10; BMI 34.1 kg/m(2)) compared with matched controls (n=10; BMI 32.1 kg/m(2)) even though the degree of weight reduction was not significantly different from women (27.4 vs 32.6%). Furthermore, VAT when adjusted for total adipose tissue (TAT) was 43% less in women post-surgery (1.2 vs 2.1 kg; P=0.03) than in controls with lower BMI (25.1 kg/m(2)). After adjustment for TAT, subcutaneous adipose tissue in women post-surgery was significantly greater than matched controls (35.1 vs 34.2 kg; P=0.03). There was a significant negative correlation of VAT and the degree of weight loss in women (r=-0.57; P=0.018) but this relationship was not significant in men (r=-0.39; P=0.27). Skeletal muscle was lower in both sexes compared with matched controls (women, 21.8 vs 23.1 kg; men, 32.5 vs 35.5 kg). CONCLUSION: Prospective studies are necessary to confirm if there is a sexual dimorphism in the effects of bariatric surgery on body composition.

CONTEXTBariatric surgery is common and may be associated with deleterious effects on the skeleton.OBJECTIVEOur objective was to assess bone metabolism and bone mineral density (BMD) after Roux-en-Y gastric bypass.DESIGN AND SETTINGWe conducted a 1-yr prospective longitudinal study at a university hospital bariatric surgery practice and metabolic bone disease unit.PARTICIPANTSParticipants included 23 obese (mean body mass index 47 kg/m(2)) men and women, aged 20-64 yr.MAIN OUTCOME MEASURESSerum PTH, 25-hydroxyvitamin D, osteocalcin, and urinary N-telopeptide, and BMD were assessed.RESULTSPatients lost 45 +/- 2 kg 1 yr postoperatively (P < 0.01). PTH increased early (3 months, 43-50 pg/ml; P < 0.001) and urinary calcium dropped (161-92 mg/24 h; P < 0.01), despite doubling of calcium intake (1318-2488 mg/d; P < 0.001). Serum 25-hydroxyvitamin D concentrations were unchanged (23-26 ng/ml), although vitamin D intake increased by 260% (658 IU/d at baseline to 1698 IU/d at 12 months; P < 0.05). Markers of bone remodeling rose (P < 0.01 for both urinary N-telopeptide and osteocalcin), whereas BMD decreased at the femoral neck (9.2%, P < 0.005) and at the total hip (8.0%, P < 0.005). These declines were strongly associated with the extent of weight loss (femoral neck: r = 0.90, P < 0.0001; and total hip: r = 0.65, P = 0.02). Lumbar spine and distal radius sites did not change.CONCLUSIONSAfter Roux-en-Y gastric bypass, there was evidence of calcium and vitamin D malabsorption. Bone turnover increased, and hip bone density rapidly declined. The decline in hip BMD was strongly associated with weight loss itself. Vigilance for nutritional deficiencies and bone loss in patients both before and after bariatric surgery is crucial.

BACKGROUND:Esophageal dilation can occur after laparoscopic adjustable gastric banding (LAGB). There are few studies in the literature that describe the outcomes of patients with esophageal dilation. The aim of this article is to evaluate weight loss and symptomatic outcome in patients with esophageal dilation after LAGB.METHODS:We performed a retrospective chart review of all LAGBs performed at Columbia University Medical Center from March 2001 to December 2006. Patients with barium swallow (BaSw) at 1 year after surgery were evaluated for esophageal diameter. A diameter of 35 mm or greater was considered to be dilated. Data collected before surgery and at 6 months and 1, 2 and 3 years after surgery were weight, body mass index (BMI), status of co-morbidities, eating parameters, and esophageal dilation as evaluated by BaSw.RESULTS:Of 440 patients, 121 had follow-up with a clinic visit and BaSw performed at 1 year. Seventeen patients (10 women and 7 men) (14%) were found to have esophageal dilation with an average diameter of 40.9 +/- 4.6 mm. There were no significant differences in percent of excess weight lost at any time point; however, GERD symptoms and emesis were more frequent in patients with dilated esophagus than in those without dilation. Intolerance of bread, rice, meat, and pasta was not different at any time during the study.CONCLUSIONS:In our experience the incidence of esophageal dilation at 1 year after LAGB was 14%. The presence of dilation did not affect percent excess weight loss (%EWL). GERD symptoms and emesis are more frequent in patients who develop esophageal dilation.

Laparoscopic gastric bypass (LGBP) is the gold standard operation for long-term weight control in the United States. Laparoscopic adjustable silicone gastric banding (LASGB) is the preferred operative method for morbid obesity worldwide. Limited data are available comparing the two procedure in the United States. This study compares weight loss, complications, and early outcome of comorbidity resolution in patients who underwent LGBP versus LASGB. A review of prospectively collected data was performed on 392 patients undergoing primary LGBP (n = 232) and LASGB (n = 160) procedures between February 2001 and July 2004. Differences in percentage excess weight lost (%EWL) at 3, 6, 12, 18, and 24 months postop, improvement or resolution of comorbidities, and complications across procedure types were evaluated. Mean initial body mass index between groups was not significantly different (LGBP 47.2 vs LASGB 47.1, p < 0.53). There were significant differences in age, gender, and self-reported sweet-eating behavior between operative groups. There was a significantly greater %EWL in patients who underwent LGBP compared to patients of the LASGB groups 3, 6, 12, and 18 months after surgery. There were no significant differences in resolution or improvement of comorbidities between the groups. Although LGBP patients experienced more complications compared to LASGB patients (5.6 vs 4.3%, respectively; p < 0.56), this did not reach statistical significance. Early after surgery, LGBP patients lose more weight than LASGB patients but have similar improvements in comorbidities. Further follow-up is needed to determine the relative long-term efficacy of these procedures.

BACKGROUND:Laparoscopic adjustable silicone gastric banding (LASGB) for morbid obesity has been reported to provide long-term weight loss with a low risk of operative complications. Nevertheless, esophageal dilation leading to achalasia-like and reflux symptoms is a feared complication of LASGB. This study evaluates the clinical benefit of routine preoperative esophageal manometry in predicting outcome after LASGB in morbidly obese patients.METHOD:A review of prospectively collected data on 77 patients who underwent routine esophageal manometry prior to LASGB for morbid obesity from February 2001 to September 2003 was performed. Aberrant motility, abnormal lower esophageal sphincter (LES) pressures, and other nonspecific esophageal motility disorders noted on preoperative esophageal manometry defined patients of the abnormal manometry group. Outcome differences in weight loss, emesis, band complications, and gastroesophageal reflux disease (GERD) resolution or improvement were compared between patients of the abnormal and normal manometry groups after LASGB. Analysis of variance (ANOVA) and chi-square tests were performed to determine the significance of these outcomes.RESULTS:Of the patients tested, 14 had abnormal esophageal manometry results, whereas 63 had normal manometry results before LASGB. There was no significant difference in percent excess weight loss (%EWL) at 6 and 12 months between the groups after gastric banding. Severe postoperative emesis occurred more frequently in patients with abnormal manometry results than in those with normal manometry results. There were two band-related complications, both of which occurred in patients of the normal manometry group.CONCLUSIONS:Preoperative esophageal manometry does not predict weight loss or GERD outcomes after LASGB in morbidly obese patients. Postoperative emesis was more common in patients with abnormal manometry findings, but such symptoms were manageable and did not lead to poor weight loss or to band removal or increased band-related complications.

Roux-en-Y gastric bypass is arguably the reference standard weight loss operation at present, with a wealth of experience in operative technique and proven surgical outcomes. Since 1994, various laparoscopic versions of the operation have been described and are widely performed. The open operation, however, is still commonly practiced [ [1] Wittgrove A.C. Clark G.W. Tremblay L.J. Laparoscopic gastric bypass, Roux-en-Ypreliminary report of five cases. Obes Surg. 1994; 4: 353-357 Crossref PubMed Scopus (639) Google Scholar ]. Three cases of complications after open Roux-en-Y gastric bypass are described, each with slightly different manifestations of a shared etiology, a reverse peristaltic alimentary limb. Two of the cases were referred to us after the primary procedure, and one operation was performed at our institution. All primary procedures were performed by different surgeons using an open technique, by way of vertical midline laparotomies above the umbilicus.

Purpose: Weight loss induced by adjustable gastric banding (AGB) and Roux-en-Y gastric bypass (GBP) is associated with metabolic improvements, although GBP generally results in greater weight loss. Changes in the orexigenic peptide, ghrelin and the anorexigenic peptides, peptide YY3-36 (PYY), and leptin may contribute to the different surgical outcomes.

To help understand the mechanisms by which weight loss is maintained after Roux-en-Y gastric bypass (RYGBP), we measured circulating concentrations of total and bioactive octanoylated ghrelin, peptide YY (PYY), glucose, and insulin in the fasted state and in response to a liquid test meal in three groups of adult women: lean (n = 8); weight-stable 35 +/- 5 months after RYGBP (n = 12; mean body mass index, 33 kg/m(2)); and matched to the surgical group for body mass index and age (n = 12). Fasting plasma total ghrelin levels were nearly identical between RYGBP (425 +/- 54 pg/ml) and the matched controls (424 +/- 28 pg/ml) and highest in lean controls (564 +/- 103 pg/ml). The response to the test meal was comparable between lean and RYGBP groups, with 27% and 20% maximal suppression, respectively, whereas the magnitude of suppression was significantly diminished in the matched controls (17%) compared with the lean group. Fasting levels of octanoylated ghrelin were highest in the lean controls, 220 +/- 36 pg/ml vs. 143 +/- 27 in the RYGBP group (P = 0.05) and 127 +/- 12 pg/ml in the matched controls (P < 0.05). The magnitude of maximal postmeal suppression of octanoylated ghrelin was more marked than with total ghrelin, but similar among groups, ranging from 44-47%. In response to the test meal, there was an early exaggerated rise in PYY in the RYGBP group, such that the peak PYY concentration was 163 +/- 24 pg/ml compared with 58 +/- 17 (P < 0.01) and 77 +/- 23 (P < 0.05) in the matched and lean controls, respectively; area under the curve at 90 min was significantly greater compared with both control groups. Leptin and fasting insulin concentrations and homeostasis model of assessment insulin resistance indices were nearly identical between lean and RYGBP subjects and significantly higher in the body mass index-matched controls. In summary, the absence of a compensatory increase in ghrelin concentrations that usually occurs with diet-induced weight loss, and the exaggerated postprandial PYY response after RYGBP, may contribute to weight loss and to the ability of an individual to maintain weight loss after this surgical procedure.

BACKGROUND:Animal studies have documented significantly better preserved postoperative cell-mediated immune function, as measured by serial delayed-type hypersensitivity (DTH) challenges, after laparoscopic-assisted than after open bowel resection. Similarly, in humans, the DTH responses after open cholecystectomy have been shown to be significantly smaller than preoperative responses; whereas after laparoscopic cholecystectomy, no significant change in DTH response has been noted. The purpose of this study was to assess cell-mediated immune function via serial DTH skin testing in patients undergoing laparoscopic or open colectomy.METHODS:A total of 35 subjects underwent either laparoscopic (n = 18) or open colectomy (n = 17) in this prospective but not randomized study. Only patients who were judged to be immunoresponsive by virtue of having responded successfully to a preoperative DTH challenge were eligible for entry in the study. DTH challenges were carried out at three time points in all patients: preoperatively, immediately following surgery, and on the third postoperative day (POD 3). Responses were measured 48 h after each challenge and the area of induration calculated. There were no significant differences between the laparoscopic (LC) and open (OC) colorectal resection groups in regard to demographics, indications for surgery, or type of resection carried out. The percentage of patients transfused was similar in both groups (17%, LC; 12% OC; p = NS). In the LC group, all cases were completed without conversion using minimally invasive methods. There were no perioperative deaths, and the rate of postoperative complications was similar in both groups. The preoperative and postoperative DTH results were analyzed and compared within each surgical group using several methods.RESULTS:In regards to the OC group results, the median sum-total DTH responses for the day of surgery challenges (0.44 +/- 69 cm2) and the POD 3 challenges (0.72 +/- 3.37 cm2) were significantly smaller than the preoperative results (3.61 +/- 3.83 cm2, p <0.0005 vs op day and p <0.0003 vs POD 3 results). When the LC group results were similarly analyzed, no significant difference in DTH response was noted between the pre- and the postoperative challenge results. Additionally, when the median percent change from baseline was calculated and considered for the OC group's DTH results, both postoperative challenge time points demonstrated significantly decreased responses when compared to their preoperative results (vs day of surgery, p <0.007; vs POD 3, p <0.006). Similar analysis of the LC group's results yielded nonsignificant differences between the pre- and postoperative responses. Lastly, when the LC and the OC groups median percent change from baseline results were directly compared for each of the postoperative challenges, a significant difference was noted for the POD 0 challenge (LC, -21%; OC 88%; p <0.004) but not for the POD 3 challenge.CONCLUSIONS:The postoperative DTH responses of the open surgery patients were significantly smaller than their preoperative responses. This was not the case for the laparoscopic group (a combination of fully laparoscopic and laparoscopic-assisted resections). When the open and laparoscopic groups results are directly compared, regarding the results of the day of surgery DTH challenges, the LC groups median percent change from baseline was significantly less than that observed in the OC group. These results imply that open colorectal resection is associated with a significant suppression of cell-mediated immune response postoperatively, whereas in this study laparoscopic colorectal resection was not. Further human studies are needed to verify these findings and to determine the clinical significance, if any, of this temporary difference in immune function following colon resection.