An Obese Rat Model of Bariatric Surgery with Gastric Banding

Background Bariatric surgery is the only treatment that can provide effective long-term weight loss for morbid obesity. However, animal models of bariatric surgery have not yet been well established. The aims of this study were to establish an obese rat model of gastric banding and to determine whether the model would replicate the procedure of human gastric banding in terms of weight loss and metabolic parameters. Methods 27 male Zucker fatty rats were divided into 3 groups: the sham-operated control, gastric banding, and diet treatment groups. They were followed for 8 weeks after surgery, and their body weight change, cumulative food intake and metabolic parameters were examined. Results For the sham-operated control, gastric banding, and diet treatment groups, the mean body weights were 644 ± 28 g, 511 ± 77 g, and 339 ± 15 g; % change of weight at 8 weeks after operaion were + 63.7 ± 8.3%, + 33.2 ± 20%, −12.0 ± 2.0%, respectively. Absolute weekly food intake amounts were 233.8 ± 38.1 g, 157.3 ± 64 g, 80 g, and cumulative food intakes were 1862 ± 111 g, 1258 ± 375 g and 640 g, respectively. The gastric banding rats showed significant decreases in weight gain, % change of weight, absolute weekly food intake, and cumulative food intake compared to sham-operated control rats (P < 0.05). The banding group also had lower levels of all metabolic parameters compared with controls (P < 0.01), and these levels were equal to those of the diet-treated group. Conclusion The present study provides a new animal model of gastric banding using obese rats. This model may be useful in research on the biochemical and molecular mechanisms of morbid obesity.     

Weight Loss After Laparoscopic Adjustable Gastric Banding is not Caused by Altered Gastric Emptying

Background  In order to know the role of gastric emptying in the mechanism of weight loss and early satiety after a restrictive surgical procedure for treatment of morbid obesity, a consecutive series of patients were scintigraphically investigated before and after laparoscopic adjustable gastric banding. Methods  Sixteen patients undergoing laparoscopic adjustable gastric banding underwent preoperatively, and at 6 months postoperatively, a gastric emptying study (solid meal and single isotope). Esophageal retention time, lag phase, peak activity time, gastric emptying rate, fundus emptying rate, and weight loss were recorded. Upper GI symptom assessment was carried out by using a standardized questionnaire. Gastric emptying parameters were correlated with the upper GI symptoms. Results  Gastric band placement showed no significant influence on postoperative gastric emptying rate [median % (interquartile range): 42 (23.3–59) preoperatively vs 38 (31–71) postoperatively and fundus emptying rate: 59(37–91) preoperatively vs 70 (53–89) postoperatively]; however, an increase in early satiety was found. Neither gastric emptying rate nor fundus emptying rate showed a relation with early satiety or weight loss. Furthermore, no correlation was found between early satiety and lag phase, esophageal retention time, start of activity, and peak activity time in proximal stomach. Conclusion  Laparoscopic adjustable gastric banding seems not to affect gastric emptying. Neither a relation between postoperative gastric emptying rate and weight loss nor between early satiety and weight loss was found. Therefore, it is unlikely that gastric emptying plays a role in the mechanism of weight loss following laparoscopic adjustable gastric banding. The authors disclose that there was no commercial interest and declare that there was no financial or material support.     

Additional Effect of Visceral Fat Resection in an Obese Rat Model of Gastric Banding

Background  There is accumulating agreement that bariatric surgery is currently the most efficacious and enduring treatment for clinically severe obesity, and as a result, the number of bariatric surgeries performed worldwide has increased in recent years. Although the function of visceral fat has gradually become clear, the effect of visceral fat resection is still unknown. The aim of this study was to clarify the additional effect of visceral fat resection in an obese rat model of gastric banding. Methods  Forty male Zucker fatty rats were divided into four groups: the control group, visceral fat resection group, gastric banding group, and gastric banding with visceral fat resection group. They were followed for 8 weeks after surgery, and their body weight change, cumulative food intake, metabolic parameters, and adipocytokines were measured. Results  The gastric banding rats either with or without visceral fat resection showed significant decreases in weight gain, cumulative food intake, and levels of metabolic parameters compared to the control rats. There were no significant differences in weight gain and cumulative food intake between gastric banding with and without visceral fat resection. However, gastric banding with visceral fat resection resulted in lower plasma levels of free fatty acid and TNF-alpha compared to gastric banding alone, and expression of adiponectin mRNA in the adipose tissue was significantly decreased with the addition of visceral fat resection compared with banding alone. There were no significant differences in any parameters between controls and rats receiving visceral fat resection alone. Conclusion  Visceral fat resection may improve adipocytokines and free fatty acid in an obese rat model of gastric banding. However, further studies are necessary before the procedure can be considered an option on bariatric surgery.     

Ghrelin and Obestatin Levels in Severely Obese Women Before and After Weight Loss After Roux-en-Y Gastric Bypass Surgery

Background  Ghrelin and obestatin are derived from the same gene but have different effects: Ghrelin stimulates appetite, and previous—albeit inconsistent—data show that obestatin may be involved in satiety. The present study was designed to test the hypothesis that Roux-en-Y gastric bypass (RYGB) surgery and/or the weight loss that reliably results from this procedure would alter levels of ghrelin and obestatin and ghrelin/obestatin ratios in a cohort of morbidly obese women. Methods  This is a longitudinal follow-up study in 18 morbidly obese women (mean weight 131.2 kg, mean body mass index [BMI] 47.4). Clinical parameters and fasting serum concentrations of ghrelin, obestatin, triglycerides, low-density lipoprotein cholesterol, glucose, and insulin were measured before and 2 years after RYGB surgery, which was associated with body weight reductions of 41.5 ± 11.6 kg (mean 62.5% excess weight loss). Results  Ghrelin concentrations (−12%, p = 0.022) and ghrelin/obestatin ratios (−14%, p = 0.017) were lower after surgery than before, while obestatin levels did not change. Changes in ghrelin concentrations correlated with changes in insulin levels (r = 0.45, p = 0.011). Most cardiovascular risk factors studied improved postsurgically (p < 0.01). Conclusion  In contrast to previous weight loss studies involving gastric banding, ghrelin levels decreased and obestatin levels remained stable after massive weight loss in long-term follow-up. The favorable gastrointestinal hormone profiles observed are likely to contribute to the long-term weight loss success rate attributed to RYGB. C.L. Roth and T. Reinehr contributed equally to this work.     

Adjustable Gastric Banding in a Morbidly Obese Patient During Liver Transplantation

The increase in morbidly obese (MO; BMI > 35) patients requiring liver transplant has mirrored the growing prevalence of obesity in the USA. However, there is considerable debate among physicians whether these patients should undergo transplantation. This is because outcome analysis shows that long-term survival following transplant is adversely affected by complications caused by MO. To date, there is little experience treating MO in transplant patients. Sustained weight reduction in MO liver transplant recipients would likely improve long-term survival and resolve the debate over whether these patients should receive a transplant. Three investigators have described good outcomes from bariatric surgical interventions following liver transplantation. But this requires a second operation with all the attendant risks of additional surgery and anesthesia. This report details an innovative step in the care of the MO transplant recipient: the placement of a gastric band at the time of transplantation. We describe the success of the combined procedure at 6 months following transplantation.     

Muscle Force and Force Control After Weight Loss in Obese and Morbidly Obese Men

BACKGROUND: Decrease in fat mass and fat-free mass have been observed with weight loss induced by a dietary intervention or surgery. There are concerns that fat-free mass decrease could have some negative functional consequences. The aim of this study was to examine how weight loss affects strength and force control in obese and morbidly obese men. METHODS: Weight loss was obtained in obese individuals by a hypocaloric diet program until resistance to lose fat and in morbidly obese individuals by bariatric surgery. Maximal force was measured for upper and lower limb and the ability to maintain 15% and 40% of that force. These measures were taken at baseline, in those dieting once resistant to weight loss and 1 year after surgery for those operated on. Normal weight individuals used for control were evaluated twice (6 to 12 months apart). RESULTS: At baseline, there was no significant difference between groups for maximal forces and capabilities to maintain force levels. Weight loss averaged 11.1% of the initial body weight after dieting and 46.3% 1 year after surgery. At the same time, there was for the lower limb a loss of 10.1% in maximal force after dieting and 33.5% after surgery. For the upper limb, there was no change in maximal force after dieting whereas a decrease of 14.4% was observed after surgery. When transformed in force related to body weight, there was no change in relative force for the lower limb after dieting whereas an increased relative force after surgery. There was no significant difference for the ability for maintaining force levels. CONCLUSION: Despite a large force loss, particularly for the lower limbs in morbidly obese individuals after surgery, this loss is relatively well tolerated because the relation between force and body weight is even improved and the ability to maintain that force is preserved.     

Comparison of Weight Loss and Morbidity after Gastric Bypass and Gastric Banding. A Single Center European Experience

Background Gastric bypass and gastric banding are widely used to treat morbid obesity and both procedures offer certain advantages. The indication for these two treatment options continue to be subject to debate. Methods A single-center case-controlled matched-pair cohort study was performed. Fifty-three primary gastric bypass patients (GB) operated between January 2002 and May 2005 were matched by gender, age, race, and initial bodyweight to 53 patients who underwent laparoscopic adjustable gastric banding (LAGB) in the same time period. Results Both groups were comparable regarding age, race, gender, preoperative body mass index, and excessive weight. Severe early complications occurred in six patients (11.3%) in the GB group and were not seen in the LAGB group. Severe late complications occurred in three patients (5.7%) in the GB group and one patient (1.9%) in the LAGB group. No mortality occurred in either group. Weight loss was significantly lower in the LAGB group than in the GB group at all time points during the follow-up. Significantly more patients were treated successfully (excess weight loss >50%) in the GB group than in the LAGB group. After 2 years, 76% of the patients in the GB group were treated successfully versus 40% of the patients in the LAGB group (P = 0.03). Conclusion Gastric bypass and gastric banding are safe and without mortality. Gastric bypass is more effective in terms of weight loss and the number of successfully treated patients. Gastric banding is a procedure with less severe complications.     

The Impact of Roux Limb Length on Weight Loss After Gastric Bypass

Background Extending the length of the Roux limb (RL) in gastric bypass (GBP) may improve weight loss in super obese patients (body mass index [BMI] > 50 kg/m²), but no consensus exists about the optimal length of the RL. We sought to determine the impact of RL length on weight loss in super obese patients 1 year after GBP. Materials and Methods One-year weight loss outcomes were analyzed in all super obese patients who underwent consecutive and primary laparoscopic or open GBP between January 2003 and June 2006. Patients were divided into two groups according to RL length (100 vs. 150 cm). The RL length was at the discretion of the attending surgeon. Baseline and follow-up data were collected prospectively. Multiple linear regression was used to adjust for potential confounders in the weight loss outcomes. Results Twelve-month follow-up data were available in 137 (85%) of 161 patients with a BMI ≥ 50 who underwent GBP during the study period. An RL of 100 or 150 cm was used in 102 (74.5%) and 35 patients (25.5%), respectively. In multivariate analysis, patients with the 150-cm RL lost more weight (68.5 vs. 55.3 kg, p < 0.01), had a greater change in BMI (25 vs. 21 kg/m², p = 0.01), and had greater excess weight loss (64 vs. 53%, p < 0.01). Conclusion A 150-cm RL provides better weight loss outcomes in super obese patients at 1-year follow-up.     

Hunger Control and Regular Physical Activity Facilitate Weight Loss After Laparoscopic Adjustable Gastric Banding

BACKGROUND: Bariatric surgery facilitates substantial and durable weight loss; however, outcomes vary. In addition to physiological and technical factors, weight loss efficacy is dependent on modification of behavior to maintain a long-term change in energy balance. This study aimed to assess the extent and nature of change in energy intake and physical activity and identify factors associated with percentage weight loss (%WL) 12 months after laparoscopic adjustable gastric banding (LAGB). METHODS: 129 bariatric surgery candidates (26 men/103 women, mean age 45.2 +/- 11.5, mean body mass index [BMI] 44.3 +/- 6.8, range 31.9 to 66.7) completed the study. Data were collected at baseline and 12 months. Validated questionnaires included the Cancer Council Victoria Food Frequency Questionnaire, Three Factor Eating Questionnaire, Short Form-36, Baecke Physical Activity Questionnaire, and Beck Depression Inventory. Symptoms of "non-hungry eating," "emotional eating," and "grazing" were assessed. RESULTS: Mean %WL was 20.8 +/- 8.5%, and excess weight loss was 50.0 +/- 20.7 (p < 0.001). Mean total energy intake reduced from 9,991 +/- 3,986 kj to 4,077 +/- 1,493 kj (p < 0.001). Average leisure time and sport-related physical activity scores increased (both p < 0.001). Regression analysis identified baseline BMI (beta = 0.241; p = 0.002), subjective hunger (beta = -0.275; p = 0.001), physical function (beta = 0.309; p < 0.001), and leisure time physical activity (beta = 0.213; p = 0.010) as independent predictors of %WL, total R (2) 0.34%. "Non-hungry eating" and symptoms of depression were also related to poorer %WL. CONCLUSION: LAGB affects marked behavior change and facilitates substantial weight loss in the first 12 months. However, variations in adopted behaviors can affect energy balance and weight loss success. Achievement and maintenance of favorable behaviors should be an important consideration during on-going postsurgical review and counseling. Management should include adequate band adjustment to control physical hunger, optimization of physical function and activity, and reinforcement of strategies to reduce energy intake.     

The Original Experimental Model in Rats to Study Gastric Banding Surgery

Background A new bariatric surgical experimental model in rats for aspects of investigation was created. Methods In 121 male Wistar rats with body mass 250–270 g, the original gastric banding (GB) operation was performed. Sixty days after the surgical procedure, we measured body mass and upper part of the alimentary tract patency (radiography with contrast medium). Results One hundred twenty one rats were operated on. In the study group, the mortality was 0%. A complication (incisional hernia) was found in only three cases. The average weight of the rat in the GB group on the 60th day after the surgery was 355.0 ± 4.12 g, and that in the sham-operation group was 394.0 ± 4.80 g (t test, t = 6,073, p < 0.001). The daily weight gain in sham-operated rats was 2.23 ± 0.07 g, whereas in the GB group, it was 1.60 ± 0.07 g (p < 0.02). Complete inhibition of weight gain was not observed. Conclusion The rat model of GB surgery that we created is easy to perform, repeatable, long-lasting, relatively cheap, and can be used in various experimental trials of diverse aspects of surgery in the field of obesity.     

The Influence of Dumping on Weight Loss After Gastric Restrictive Surgery for Morbid Obesity

Background: The dumping syndrome that follows Roux-en-Y gastric bypass for morbid obesity is considered to be the primary mechanism of improved weight loss as compared with the purely restrictive vertical banded gastroplasty. To evaluate the influence of dumping on post-operative weight loss, severity of dumping was determined using Sigstad's clinical diagnostic index. Methods: One hundred and thirty seven gastric bypass and 19 gastroplasty patients were assessed 18-24 months following surgery. Sigstad's criteria for the dumping syndrome were met by 75.9% of gastric bypass and no gastroplasty patients. Among gastric bypass patients, no relationships were found between severity of dumping and weight loss, as measured by per cent of excess body weight loss or change in body mass index. Weight loss was significantly greater with gastric bypass than gastroplasty patients (72.5 compared to 47.9% of excess body weight loss). All gastroplasty and 24.1% of gastric bypass patients were classified as nondumpers. The difference in weight loss between surgical procedures was not related to dumping: gastric bypass non-dumpers lost significantly more weight (69.1% excess body weight loss) than gastroplasty patients. Conclusions: This study fails to demonstrate a significant relationship between dumping severity and weight loss. It is inferred that the superior weight loss of gastric bypass compared to gastroplasty has some other etiology.     

Different Effect of Laparoscopic Roux-en-Y Gastric Bypass and Open Biliopancreatic Diversion of Scopinaro on Serum PYY and Ghrelin Levels

Background  The impact of bariatric surgery on levels of peptide YY (PYY) and ghrelin is still under discussion. We undertook a simultaneous evaluation of the serum changes in PYY and ghrelin depending on the specific type of bariatric surgery. Methods  Total PYY and ghrelin were analyzed in 29 healthy persons and in morbidly obese persons undergoing open biliopancreatic diversion (BPD) of Scopinaro (n = 38) or laparoscopic Roux-en-Y gastric bypass (RYGB; n = 13). Results  RYGB resulted in a significantly greater loss of weight and body mass index than BPD. Both RYGB and BPD were associated with a significant increase in PYY, significantly greater for BDP (p = 0.001). Ghrelin rose significantly after RYGB (p = 0.022) but not after BPD. After surgery, PYY correlated positively with weight (r = 0.416, p = 0.009). Ghrelin did not correlate significantly with any of the variables studied. Analysis of variance showed that only the type of surgery contributed significantly to explain the variances in the PYY (p = 0.002) and ghrelin (p = 0.018). Conclusions  BPD results in a greater increase in PYY and a lower weight loss than RYGB. However, only RYGB was associated with a significant increase in ghrelin. The differing weight loss according to the type of bariatric surgery does not seem to be explained by changes arising in PYY and ghrelin.     

High Ghrelin Concentration is Not a Predictor of Less Weight Loss in Morbidly Obese Women Treated with Laparoscopic Adjustable Gastric Banding

Background: We analyzed the role of high plasma ghrelin concentrations at surgery as a negative predictor of weight loss in morbidly obese patients treated with laparoscopic gastric banding (LAGB). Methods: Fasting plasma ghrelin concentrations were measured in 113 women before LAGB, and 16 of them were identified as having ghrelin concentrations clearly higher than expected according to the BMI levels. The 2-year postoperative outcome of these 16 patients was compared to the outcome of the remaining subjects. Results: Mean fasting plasma ghrelin concentration in the group with hyperghrelinemia was 82.3±23.1 pg/ml and in women with normal ghrelin was 27.1±11.3 pg/ml (P <0.001). No differences in age, age at onset of obesity or degree of obesity were observed between the two groups. Women with hyperghrelinemia had a weight gain during the waiting time similar to women with normal ghrelin. The prevalence of comorbities and eating behavior disturbances was similar in the two groups, but depression was 2.5 fold more prevalent in the hyperghrelinemic women than in the women with normal ghrelin. The %EWL after LAGB surgery was similar in women with high and normal ghrelin concentrations, with no differences in levels of postoperative band filling. No differences in band-related complications or revisional surgery rate were observed between the two groups. Conclusion: A high fasting ghrelin concentration at baseline did not significantly affect the outcome after LAGB in morbidly obese women, in terms of weight loss and complications rate.     

Effect of Preoperative Knowledge on Weight Loss After Laparoscopic Gastric Bypass

INTRODUCTION: Gastric bypass surgery has been demonstrated to be an effective treatment for morbid obesity. Unfortunately, not all patients have the same weight loss after surgery. It may be that the more informed patients will have more weight loss than less informed patients. No study has investigated the relationship between initial preoperative knowledge and weight loss after laparoscopic gastric bypass surgery. METHODS: All patients who underwent laparoscopic gastric bypass for a 6-month period were included in this study. Our preoperative education process includes a 21-question true/false test given at the appointment immediately before surgery. Patients repeat the test until all questions are answered correctly. We compared percentage of excess body weight loss (EBWL) between patients who correctly answered all the questions the first time (pass patients) and patients who did not correctly answer all the questions the first time (fail patients). RESULTS: There were 104 patients involved in this study; although complete data were only available on 98 patients. The average preoperative body mass index was 48 kg/m(2). Forty-eight percent of patients answered all the questions correctly the first time. Follow-up ranged from 1 to 2 years on all 98 patients. Pass patients had an average of 73% EBWL, whereas fail patients had an average of 76% EBWL (p = NS). CONCLUSIONS: Preoperative knowledge, assessed by a test, did not predict success after laparoscopic gastric bypass surgery. Patients who do not, at first, have full knowledge of bariatric surgery should not be discriminated against undergoing surgery if they are eventually properly educated.     

Relation Between Carbohydrate Intake and Weight Loss After Bariatric Surgery

Background  Weight loss and long-term weight maintenance in bariatric surgery patients are related to maintaining satiety. It can be related to glycemic load (GL) and carbohydrate (g CHO) intake. The aim of this study was to investigate the effect of g CHO and GL and in weight loss on patients who had undergone bariatric surgery. Method  The following measurements/calculations were conducted as follows: current body weight (kg), current BMI, percentage of excess weight loss (PEWL), average monthly weight loss (AMWL), energy intake (kcal per day), and GL calculation. Correlations were found among the studied variables. A multiple linear regression analysis of diet variables executed with GL and weight loss. Results  The population presented 66% of EWL. The average of total energy intake (TEI) was 1220 ± 480, and the calculated GL resulted in an average of 73.2. Negative correlations were found between AMWL and TEI (p = 0.04), and between AMWL and GL (p = 0.009); furthermore, a negative correlation was found between carbohydrate intake in grams and AMWL (p = 0.003). A positive correlation (p = 0.017) was found between GL and TEI. Weight loss and GL were also correlated. Among the intake variables, GL and g CHO consumed are held accountable for 62 percent of AMWL. The multiple linear regression analysis showed that GL and carbohydrate grams (g CHO) account for 62% of AMWL. Conclusion  The glycemic load and grams of carbohydrate are intake factors that can be useful tools in weight loss and long-term weight maintenance on patients who have undergone Roux-en-Y Gastric Bypass (RYGB).     

Preliminary Results of the Laparoscopic Adjustable Gastric Banding Procedure by a New Generation of Silicone Band: MIDBAND

Background

The surgical treatment of morbid obesity by laparoscopic adjustable gastric banding has become a “gold standard” in Europe. Currently, five types of silicone bands are used in the majority of countries performing bariatric surgery.

Methods

The MIDBAND® was introduced to the European market in 2000. It is placed around the stomach using the Pars Flaccida technique described by Forsell. A prospective multicentric study on 113 cases was carried out to evaluate technical feasibility, complications, and the midterm weight loss outcomes (2 years).

Results

The percentage of excess body weight loss was 52.58% at 2 years. Perioperative mortality was nil and the complication rate was low (slippage <2%).

Conclusion

These encouraging results require longer-term studies to validate this procedure.     

Effect of Weight Loss on Bone Mineral Density Determined by Ultrasound of Phalanges in Obese Women After Roux-en-y Gastric Bypass: Conflicting Results With Dual-Energy X-ray Absorptiometry

The rapid weight loss that occurs in obese patients submitted to Roux-en-y gastric bypass (RYGB) as well as the changes in dietary pattern and the intestinal malabsorption result in changes in bone mineral density (BMD). The objective of the present study was to assess the changes in BMD after the weight loss induced by RYGB using ultrasound of the phalanges and compare the results with those obtained by dual-energy X-ray absorptiometry (DXA). We conducted a 1-yr prospective longitudinal study on women with grade III obesity submitted to RYGB. Anthropometric (weight, height, body mass index, and abdominal circumference) and body composition measurements by electrical bioimpedance, assessment of food consumption by 24-h recall, biochemical evaluation, and assessment of BMD by ultrasonography of the phalanges and DXA (BMD values are from the 33% radius site) were performed during the preoperative period and 3, 6, and 12 mo after surgery. The mixed-effects linear regression model was used to analyze the effect of postoperative time on the variable of interest, and the kappa coefficient (p < 0.05) was used to compare the concordance of the methods used for BMD evaluation. Twenty-nine patients were included in the study. During the 1-yr follow-up, a reduction of 39 ± 8 kg (71 ± 15% of excess weight) and 29 ± 7 kg of fat mass was observed. Calcium and zinc concentrations were reduced after 12 mo. No difference in caffeine, calcium, or sodium consumption was observed between the preoperative and postoperative periods. Analysis of BMD by ultrasonography of the phalanges 1 yr after surgery showed increased values of amplitude-dependent speed of sound (2064.6 ± 59.4 vs 2154.7 ± 63 m/s; p < 0.001) and ultrasound bone profile index (0.73 ± 0.13 vs 0.76 ± 0.14; p < 0.001). Analysis of BMD by DXA showed a reduction of BMD values (0.6 ± 0.04 vs 0.57 ± 0.05 g/cm³; p < 0.001) in the sixth month and maintenance of the values from the sixth to the 12th month. At the end of the study, there was no concordance between the methods for BMD analysis. This study showed improvement in bone quality and quantity assessed by ultrasonography. However, the DXA results showed a reduction in BMD after 12 mo of RYGB. Thus, the BMD measurement methods were discordant.     

The Increase in Serum Visfatin After Bariatric Surgery in Morbidly Obese Women is Modulated by Weight Loss, Waist Circumference, and Presence or Absence of Diabetes Before Surgery

BACKGROUND: Previous studies addressing the changes in serum visfatin levels after bariatric surgery yielded conflicting results. METHODS: We measured serum visfatin levels in 41 morbidly obese women before bariatric surgery and after losing at least 15% of the initial weight, and analyzed the results taking into account the type of surgery, reproductive and diabetic status, among others. Body mass index, waist circumference, lipid profile, and insulin resistance determined by homeostasis model assessment (HOMA-IR) were also measured. RESULTS: Patients lost 30.3 +/- 6.1% of the initial body weight, and serum visfatin levels increased from 22.2 +/- 20.9 to 32.2 +/- 27.6 ng/ml (P = 0.031). A multiple regression model (R (2) = 0.314, F = 3.555, P = 0.017) including the percentage of weight loss, changes in waist circumference, HOMA-IR, high-density lipoprotein-cholesterol, and triglycerides (also expressed as percentage from baseline), the surgical procedure, time elapsed since surgery, and previous diabetic status as independent variables showed that weight loss (beta = -0.670, P = 0.010), previous diabetic status (beta = -0.330, P = 0.036), and change in waist circumference (beta = 0.556, P = 0.031) were the main determinants of the percentual increase in serum visfatin levels observed after bariatric surgery. CONCLUSION: Serum visfatin increased after bariatric surgery in relation to the amount of weight lost and to the changes in waist circumference, and this increase was higher in diabetic patients.     

Predictors of Weight Loss and Effectiveness of Roux-en-Y Gastric Bypass in the Morbidly Obese Hispano-American Population

Background  Co-morbidities and the metabolic response to intervention in morbid obesity have been reported to vary among different ethnic groups. We compared the rate of weight loss, effectiveness of gastric bypass surgery, and variables influencing success after gastric bypass in Hispanics compared to Caucasians. Methods  Morbidly obese adult (>18 years old) patients (body mass index [BMI] 40 or above) evaluated by our bariatric group from 2005 to 2006 who underwent Roux-en-Y gastric bypass (RYGBP) were studied. Every patient was evaluated for height, weight, BMI, percent body fat, fat mass, serum metabolic analysis (SMA) 12, lipid profile, complete blood count (CBC), iron, ferritin, Vitamins A, D, and B1, complete urinalysis and Fibrospect score II. Weight loss was evaluated at 1, 3, 6, and 12 months. Results  Seventy-five patients underwent successful open RYGBP with no mortality. Regardless of the significant difference in age and co-morbidities, the mean percentage of total weight loss after 1 year of follow-up was 32% for Hispanics and 30% for Caucasians with no significant difference (p > .5). When comparing the percentage of excess weight lost (% EWL) at 1, 3, 6, and 12 months, there was no significant difference between both groups. Using multiple regression analysis, we found that high-density lipoprotein (HDL) and systolic blood pressure (SBP) significantly predicted EWL at 12 months in Caucasians and Fibrospect predicted significantly EWL at 1 year. Conclusion  At 1 year after RYGBP, both ethnic groups lost ∼77–80% of their EWL and BMI. All Caucasians and 95.7% of Hispanics achieved successful weight loss (>50% EWL).     

Gastric Bypass Surgery Causes Body Weight Loss Without Reducing Food Intake in Rats

Background It is a common dogma that gastric bypass (GB) induces early satiety and consequent reductions in food intake and nutrient absorption. The aim of the present study was to analyze feeding behavioral and metabolic changes in rats after GB. Methods Male Sprague–Dawley rats at the ages of 23 and 42 weeks were placed in metabolic cages connected with a comprehensive laboratory animal monitoring system. At the age of 48 weeks they were subjected to either GB or sham operation, and then placed in metabolic cages at 51 and 62 weeks (or 3 and 14 weeks postoperatively). Results GB rats lost 20% of the body weight within 2–3 weeks and remained at this lower level until the end of the study at 14 weeks postoperatively. Satiety ratio was higher during daytime than nighttime in both sham-operated and GB rats, but was not significantly different between the two groups. Neither daily accumulated food intake nor food intake per 100 g of body weight was different between sham-operated and GB rats. Apparently, GB rats ate more frequently during daytime and had smaller meal size during nighttime at 3 weeks postoperatively. These changes were not present at 14 weeks postoperatively. Energy density in the feces was the same in GB and sham-operated rats postoperatively. Energy expenditure declined with age, but increased in GB rats compared with age-matched sham-operated rats. Conclusions GB reduced the body weight without causing early satiety, reducing food intake or inducing malabsorption. It did, however, increase energy expenditure.